Governments are often accused of responding only to short-term and parochial considerations. It is therefore remarkable that representatives of 190 countries recently committed themselves at the Convention on Biological Diversity to reducing biodiversity loss. This presents conservation biologists with perhaps their greatest challenge of the decade. The authors of this Policy Forum describe approaches to identifying more of the earth's biological diversity; understanding how biological, geophysical, and geochemical processes interact; and presenting scientific knowledge in time to contribute to and achieve the 2010 target.

North Western European populations of White Storks (Ciconia ciconia) appear to have been saved from extinction by settling, i.e. stopping migration. Settled storks exposed to winter conditions must cope with periods of potentially high energy demands that would otherwise be avoided by the migration process. Doubly labeled water (DLW) was therefore used to examine the seasonal variation (summer vs winter) in daily energy expenditure (DEE) and the body composition of adult and immature storks of both sexes. Male White Storks showed a higher DEE over the winter period than in summer compared with females; in particular, immature males exhibited greater energy expenditure in winter than adult males. Thus, the DEE did not significantly differ between summer and winter (except for immature males), reflecting an absence of thermoregulation cost in winter. For both age classes, total body mass increased in winter, which was mainly due to an increase in fat mass. Adult storks were 5% heavier than immature storks. The sexes differed in body mass, with males weighing significantly more than females by 11%. Mean LBM (lean body mass) was 8.5% higher in adults than in immatures, and was 11.5% higher in males compared with females. Between their first and second summers, immatures accumulated a lean body mass to finally reach the same values as adults, indicating a phase of muscle development. The mean fat mass of the storks did not differ between age classes or between sexes. Based on physiological parameters, this study shows that settled White Storks are able to cope with mild winter periods when they are artificially provided with food. In a view to preserve favourable habitats for this species, it is therefore necessary to decide on a plan of action for breeding areas.

P-type ATPases are membrane proteins that couple ATP hydrolysis with cation transport across the membrane. Ten different subtypes have been described. In mammalia, 15 genes of P-type ATPases from subtypes II-A, II-B and II-C, that transport low-atomic-weight cations (Ca²⁺, Na⁺, K⁺ and H⁺), have been reported. They include reticulum and plasma-membrane Ca²⁺-ATPases, Na⁺/K⁺-ATPase and H⁺/K⁺-ATPases. Enterocytes and colonocytes show functional differences, which seem to be partially due to the differential expression of P-type ATPases. These enzymes have 9 structural motifs, being the phosphorylation (E) and the Mg²⁺ATP-binding (H) motifs the most preserved. These structural characteristics permitted developing a Multiplex-Nested-PCR (MN-PCR) for the simultaneous identification of different P-type ATPases. Thus, using MN-PCR, seven different cDNAs were cloned from enterocytes and colonocytes, including SERCA3, SERCA2, Na⁺/K⁺-ATPase a1-isoform, H⁺/K⁺-ATPase a2-isoform, PMCA1, PMCA4 and a cDNA-fragment that seems to be a new cassette-type splice-variant of the atp1a1 gen. PMCA4 in enterocytes and H⁺/K⁺-ATPase a2-isoform in colonocytes were differentially expressed. This cell-specific expression pattern is related with the distinctive enterocyte and colonocyte functions.

Schistosoma mansoni cathepsin B (Sm31) is a major antigen from adult worms that circulates in the blood of infected patients (Li et al., Parasitol Res 1996; 82: 14—18). An analysis of the Sm31 sequence (Klinkert et al., Mol Biochem Parasitol 1989; 33: 113—122) allowed the prediction of seven hydrophilic regions that were confirmed to be exposed on the surface of a 3D model of Sm31; the species specificity of these regions was checked using BLAST analysis. The corresponding peptides were chemically synthesized in polymerazible forms using the t-Boc technique. Rabbits developed a high humoral response against these peptides as tested by a multiple antigen blot assay; it recognized native Sm31 in crude S. mansoni extracts and as circulating antigen in sera of S. mansoni-infected patients by western blot. Relevant antigenic determinants were located at the N- and C-terminus sequences. Antibodies against these regions recognized the native enzyme in an ELISA-like assay called cysteine protease immuno assay in which the immunocaptured enzyme was revealed by the intrinsic cathepsin B hydrolytic activity of Sm31. The method successfully and specifically detected Sm31 in sera of infected individuals, most of them (83·3%) with light infections, offering a rationale for the development of parasite enzyme capture assays using anti-synthetic peptide antibodies for possible use in the diagnosis of schistoso,iasis.

Cr has been added to FeCo substituting 10 at.% of Co or Fe in the alloy. The alloys Fe₅₀Co₄₀Cr₁₀, Fe₄₀Co₅₀Cr₁₀ and Fe₅₀Co₅₀ were prepared by mechanical alloying for 2, 5, 10, 20, 40 and 60 h. The formation of the alloy and the incorporation of the elements have been followed by X-Ray Diffraction (XRD) and Mössbauer Spectroscopy. The kinetics of mixing occurs by incorporation of Co and Cr into the Fe structure. After prolonged milling it seems that Cr incorporates itself into both -Fe and -FeCo structures and a mixture of FeCoCr rich in Cr and FeCoCr rich in Co solid solutions is obtained.

Areas of resonance signals present in 12 frequency bins of the ¹H NMR spectra of the vacuum residues of five Colombian crudes and a blend were correlated with their SARA components and some physicochemical properties. The residues studied were obtained from light paraffinic to heavy aromatic Colombian crudes. Correlations between the NMR spectra and properties were obtained with partial least square PLS and multiple linear regression MLR. Prediction models for SARA obtained by PLS had R² %26gt; 0.97 while CV - q² was between 0.92 and 0.99. Models obtained with MLR for SARA showed a high for the first three components and a lower one for asphaltene. The R² of the prediction models for density, API Gravity, S, N, Ni ppm and wax %m content plus nC5- and -C7 insolubles were %26gt;0.988 while CV - q² was between 0.87 and 0.99. The proposed correlation methods are fast and less costly than the conventional ones.

Although there is evidence suggesting that statins may exert an endothelial protecting effect, recent in vitro data have shown that these compounds may induce endothelial cells (EC) apoptosis. We previously reported that the Fas-death receptor may induce apoptosis of the liver sinusoid endothelial cells (LSEC), and that TNF-a increases the susceptibility of these cells to suffer Fas-mediated apoptosis. Based on this evidence, in this study, we investigated the effect of simvastatin on Fas-mediated LSEC apoptosis. Simvastatin induced a significant reduction in LSEC viability, in a dose dependent manner, under serum-containing or serum-free conditions. This effect was prevented by mevalonate and GGPP, indicating the role of hydroxy-3-methylglutaryl-CoA reductase. The simvastatin effect on LSEC death was not associated with increased activation of caspase-3. We found that simvastatin increased the susceptibility of LSEC death mediated by Fas. Further, simvastatin increased LSEC-apoptosis induced by Fas and TNF-a. Mevalonate and GGPP partially prevented simvastatin-induced sensitization to LSEC death mediated by Jo2 and TNF-a, but not Jo2 alone. Simvastatin did not induce up-regulation of the Fas on the LSEC. Our results provide evidence of simvastatin in modulating Fas-mediated apoptosis in endothelial cells. These results may have clinical implications in those clinical conditions associated with high levels of FasL and TNF-a

Brown widow spider (BrWS) (Latrodectus geometricus) venom produces intense systemic reactions such as cramps, harsh muscle nociceptive, nauseas, vomiting and hypertension. The proposed pathogenic mechanisms resulting in these accidents have principally been damages occurring at the nervous system. However, it is suspected that there is also damage of the adrenal glands, as a result of the experimental animal's clinical manifestations, which developed symptoms compatible with acute adrenal insufficiency. We have currently found that the adrenal gland is damaged by this venom gland homogenates (VGH) producing severe alterations on cortex cells resulting in death by acute adrenal insufficiency. In general, the ultrastructural study on the glands of mice under transmission electronic microscopy observations showed alterations in the majority of the intracellular membranes within 3 to 24 h. BrWSVGH also showed specific actions on extracellular matrix proteins such as fibronectin, laminin and fibrinogen. In addition, zymogram experiments using gelatin as substrates detected gelatinolytic activity. The molecular exclusion fractionation of crude BrWSVGH resulted in 15 fractions, of which F1 and F2 presented a/ß-fibrinogenase and fibronectinolytic activities. Fractions F6, F14 and F15 showed only a-fibrinogenase activity; in contrast, the gelatinolytic action was only observed in fraction F11. Only metalloproteinase inhibitors abolished all these proteolytic activities. Our results suggest that adrenal cortex lesions may be relevant in the etiopathogenesis of severe brown widow spider envenoming. To our knowledge, this is the first report on adrenal gland damages, fibrinogenolytic activity and interrelations with cell-matrix adhesion proteins caused by L. geometricus VGH. The venom of this spider could be inducing hemostatic system damages on envenomed patients

Quantum chemistry calculations were carried out, using ONIOM2 methodology, in order to investigate the thiophene interaction with gold supported on silicoaluminophospates molecular sieves (Au/SAPO-11) catalysts. Two models were studied, one containing one Au atom per site, and the other with two Au atoms per site. Thiophene adsorption was found to be ?¹ type. This adsorption presents a ?H of -13.2 and -9.7 kcal/mol, for the models with one Au atom (Au/SAPO-11), and two Au atoms (Au₂/SAPO-11), respectively. The partial hydrogenation of the thiophene—Au/SAPO-11 and thiophene—Au₂/SAPO-11 complexes gives 2,5-dihydrothiophene (DHT), with a ?H of -23.0 and -36.8 kcal/mol, respectively. 2-Butene production was found in both models with further hydrogenation. Likewise the direct butadiene elimination is achieved, but only with the separated Au dimer (?H = -17.5 kcal/mol).

The formation of organic molecules of the type XH_n, where X is H, C, N and O and n=1-4, on the hydrogenated surface of a polycyclic aromatic hydrocarbon flake (coronene) has been examined in detail with the CATIVIC parametric quantum chemical code. Hydrogen chemisorption on different sites, surface—adsorbate bonding properties and layer formation are studied. The interactions of H, O, N and C on one-center sites of the H-saturated monolayer give rise to the formation of free H₂, OH and NH while the CH molecule remains attached to the surface. Reactions on two-center sites lead to the formation of the free triatomic molecules H₂O, NH₂ and CH₂. One-center interactions of OH, NH, NH₂, CH₂ and CH₃ also result in the respective formation of H₂O, NH₂, NH₃, CH₃ and CH₄. We find that the reactions of atoms and small molecules with the hydrogenated coronene surface in most cases must overcome relatively high energy barriers in order to lead to reaction products.

Several tissues from different animals, including the rat kidney and the freshwater rainbow trout gills, show an ouabain-insensitive, furosemide-sensitive, Na⁺-stimulated ATPase activity, which has been associated with the active control of the cell volume. This Na-ATPase is Mg²⁺ dependent and it is inhibited by vanadate, which can be taken as an indication that this enzyme is a P-type ATPase. The P-type ATPases are known to form a phosphorylated intermediate during their catalytic cycle, where the phosphate binds an aspartyl residue at the enzyme's substrate site. In the current study, we partially characterized the phosphorylated intermediate of the ouabain-insensitive Na-ATPase of rat kidney cortex homogenates and that of gill microsomes from freshwater rainbow trout. While the kidney cortex homogenates, under our assay conditions, show both Na- and Na,K-ATPase activities, the gill microsomes, when assayed at pH 5.2, only show Na-ATPase activity. Both preparations showed a Mg²⁺-dependent, Na⁺-stimulated phosphorylated intermediate, which is enhanced by furosemide. Incubation of the phosphorylated enzyme with 0.6 N hydroxylamine (NH₂OH) showed that it is acid-stable and sensitive to hydroxylamine, either when phosphorylated in the presence or absence of furosemide. Addition of ADP to the incubation medium drives the reaction cycle of the enzyme backward, diminishing its phosphorylation. Na⁺ seems to stimulate both the phosphorylation and the dephosphorylation of the enzyme, at least for the Na-ATPase from gill microsomes. In a E1—E2 reaction cycle of the Na-ATPase, furosemide seems to be blocking the transition step from Na·E1P to Na·E2-P.

This work presents the results of ¹³⁷Cs, ⁴⁰K, ²³²Th and ²³⁸U concentration (Bq kg^-1) values in coastal marine sediments collected from 38 sites along the coastline of the island of Margarita, Venezuela. The purpose was to determine baseline values for these radionuclides in surface marine sediments and to detect if there were any anomalously high concentration values. Only three of the 38 sediments analyzed had measurable values above the detection limit of 0.9 Bq kg^-1 for ¹³⁷Cs and the highest only being 1.4 Bq kg^-1. While, the concentration (Bq kg^-1) ranges for the primordial radionuclides, ⁴⁰K, ²³²Th and ²³⁸U were as follows: 12.2-211.7 Less than 1.5-9.8 and Less than 4.4-20.7, respectively. These concentration ranges for the primordial radionuclides can be considered as baseline values for surface marine sediments for areas that are considered not polluted by man or contaminated by nature. Finally, the concentration range of ¹³⁷Cs can also be employed as baseline values, which only seem to have been the result of the atmospheric testing of nuclear weapons in the past.

Trypanosoma evansi is the causative agent of equine trypanosomoses. The disease is characterized by fever, anemia, and cachexia. Peroxidative damage of the red blood cells caused by the parasite, may contribute to the pathogenesis of the anemia seen in trypanosomoses. Consequently, we evaluated the hematocrit, the osmotic fragility of the red blood cells, the level of lipid peroxidation and the activity of the Ca-ATPase of red blood cell ghosts from rats experimentally infected with T. evansi. After 72 h inoculation, the hematocrit decreased from 49.5% to 33%; the osmotic fragility of the red blood cells was approximately 40% higher as compared to the healthy animals; and the red blood cell ghosts showed a higher level of lipid peroxidation and a lower Ca-ATPase activity than the red cell ghosts from the healthy animals. In vitro incubations of red blood cells from healthy animals with T. evansi, produced also a significant increase of the osmotic fragility of the red blood cells.

Zirconia-supported nickel catalysts with different amounts of aluminum (Al/Zr = 0.2, 1 and 2) were studied in this work in order to find alternative supports for nickel-based catalysts for the partial oxidation of methane. This reaction is a promising route for producing hydrogen and syngas for different applications. Samples were prepared by precipitation and impregnation techniques, characterized by several techniques and evaluated in the partial oxidation of methane in the range of 450—750 °C and 1 atm. It was found that aluminum affects the textural and catalytic properties of zirconia-supported nickel catalysts. The tetragonal phase of zirconia was stabilized by aluminum and gamma-alumina was also found in the aluminum-richest samples. Aluminum increased the porosity and the specific surface area of the solids. The catalytic activity also increased with the amount of aluminum in solids probably due to the stronger interaction of nickel with the support, which slowly generates active sites during the reduction step. The methane conversion and hydrogen selectivity increased with temperature, indicating no deactivation. The hydrogen to carbon monoxide molar ratio decreased due to aluminum but was not significantly affected by temperature. The coke produced was not harmful to the catalysts and aluminum affected its amount, although no simple relationship was found between these parameters. The most promising catalyst was the sample with aluminum to zirconium molar ratio of 2, which showed high activity and hydrogen selectivity and was stable under the reaction condition.

The effect of passivation and presulfidation after carbiding of activated carbon-supported Fe—Mo, Co—Mo and Ni—Mo catalysts on their thiophene HDS activity was evaluated. Catalytic precursors were prepared by co-impregnation of the support with solutions of ammonium heptamolybdate and the promotor nitrates or sulfates. Carbiding was achieved by means of the carbothermal method, employing pure H₂ as reductant and the support as the carbon source. Carbided samples were submitted to one out of three types of procedures before HDS tests: (a) passivation at room temperature followed by presulfiding; (b) presulfiding (no passivation); and (c) neither passivation nor sulfiding before HDS. Samples of passivated catalysts prepared from the sulfates of Fe, Co or Ni contained variable amounts of sulfur, as shown by XPS and elemental analysis, while XRD showed only metals and mixed Fe₃Mo₃C or ?-M₆Mo₆C₂ (MCo, or Ni) phases. The nitrate-derived catalysts only presented ß-Mo₂C and metals (XRD). Sulfur containing catalysts showed high initial activities although deactivate strongly during the first 40 min on the reaction stream, while the unsulfided nitrate-derived samples showed a more stable behavior and lower activities during the 2—3 h of testing. In general, samples submitted to passivation followed by presulfiding showed the higher steady state activities and those neither passivated nor sulfided were the less active. The results show the benefits of a passivating treatment on these carbon-supported catalysts, and point out to the importance of sulfided surface phases in HDS on carbides of transition metal catalysts.

In the present work, the thermodegradative and morphological behavior of composites of high-density polyethylene and surface-treated hydroxyapatite (HDPE/HA) were studied. Composites were prepared with HDPE, 30 wt% of HA and 2 phr of an ethylene—acrylic acid copolymer (20 wt% of acrylic acid) (EAA) and melt-blended in an internal mixer at 160 °C and 50 rpm. Two sets of composites filled with different surface-treated hydroxyapatite (STHA) were prepared: one HA sample was pretreated with ethylene—acrylic acid copolymer (STHA₁) and the other one with acrylic acid (STHA₂). Thermogravimetric analyses were carried out to evaluate the thermal stability of the composites. The activation energies (Ea) were determined using a numerical method based on the Invariant Kinetic Parameters (IKP). The thermal decomposition of the HDPE/HA composites showed an Ea value of 330 kJ/mol. On the other hand, HDPE/HA/EAA and HDPE/STHA₁ composites showed a sudden decrease in Ea (272 and 270 kJ/mol, respectively). The HDPE/STHA₂ composite exhibited an Ea value of 313 kJ/mol, slightly lower than that of the HDPE/HA composite. Additionally, with the presence of EAA copolymer and acrylic acid in the composites, the nucleation and nucleus growth kinetic-model probabilities decreased compared to those of the HDPE/HA composite. However, there was an increase in the probability of the reaction order of the model. This behavior could be attributed to the morphology of the composites and to the addition of a less thermally stable component, i.e. EAA copolymer and acrylic acid. On the other hand, due to the interaction polymer/surface-treated filler, an increase in the Young Modulus and the tensile strength was observed.

The behavior of the poly(methyl methacrylate) (PMMA) under the action of gamma radiation has been sufficiently studied. In this work, we present results from melt flow index (MFI), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and electron paramagnetic resonance (EPR) of PMMA composites with hydroxyapatite (HA) and seaweed residues (SW) irradiated with gamma rays at 1.08 kGy/h. Composites of PMMA/HA and PMMA/SW with 10%, 20% and 30% of the filler were prepared. The results show an increase in the MFI values with the integral dose of radiation, being consistent with chain-scission reactions. No EPR signal was observed in pure PMMA, while in the composites, the typical EPR signal of the PMMA radicals was observed, which increased with the amount of HA or SW. When comparing the relative intensities of the EPR signals for both types of composites, a slight increase in the concentration of free radicals generated in the sample with SW respect to that of PMMA/HA composite was obtained. A decay of the total free radical concentration was observed as time elapsed.

Most forms of visceral pain generate intense referred hyperalgesia but the mechanisms of this enhanced visceral hypersensitivity are not known. The on-cells of the rostral ventromedial medulla (RVM) play an important role in descending nociceptive facilitation and can be sensitized to somatic mechanical stimulation following peripheral nerve injury or hindpaw inflammation. Here we have tested the hypothesis that visceral noxious stimulation sensitizes RVM ON-like cells, thus promoting an enhanced descending facilitation that can lead to referred visceral hyperalgesia. Intracolonic capsaicin instillation (ICI) was applied to rats in order to create a hyperalgesic state dependent on noxious visceral stimulation. This instillation produced acute pain-related behaviors and prolonged referred hyperalgesia that were prevented by the RVM microinjection of AP5, an NMDA selective antagonist. In electrophysiological experiments, ON-like RVM neurons showed ongoing spontaneous activity following ICI that lasted for and an enhanced responsiveness to von Frey and heat stimulation of the hindpaw and to colorectal distention (CRD) that lasted for at least 50 min post capsaicin administration. Moreover, ON-like cells acquired a novel response to CRD and responded to heat stimulation in the innocuous range. OFF-like neurons responded to capsaicin administration with a brief (Less Than 5min) inhibition of activity followed by an enhanced inhibition to noxious stimulation and a novel inhibition to innocuous stimulation (CRD and heat) at early time points (10 min post capsaicin). These results support the hypothesis that noxious visceral stimulation may cause referred hypersensitivity by promoting long-lasting sensitization of RVM ON-like cells.

In contrast to other metal-dithiocarbamate [DEDTC] complexes, the copper-DEDTC complex is highly cytotoxic, inducing oxidative stress, preferentially in tumor cells. Because nitric oxide (NO) forms adducts with Cu[DEDTC]₂, we investigated whether NO donors like S-nitroso-N-acetyl penicillamine (SNAP) or sodium nitroprusside (SNP), and nitrite, a NO decomposition product, modulate Cu[DEDTC]₂ cytotoxicity against human tumor cells. We show that apoptosis-associated PARP cleavage and inducible nitric oxide synthase (iNOS) down-regulation induced by nanomolar Cu[DEDTC]₂, are counteracted by 50 µM SNAP, SNP, or CoCl₂, an inducer of hypoxia and NO signaling. Nitrite was stochiometrically effective in antagonizing Cu[DEDTC]₂ cytotoxicity and inducing shifts in the absorption spectrum of the binary complex in the 280 and 450 nm regions. Subtoxic concentrations of Cu[DEDTC]₂ became lethal when tumor cells were pretreated with c-PTIO, a membrane-impermeable scavenger for extracellular NO. Our results suggest that: (a) reactive oxygen species induced by Cu[DEDTC]₂ are scavenged by nitrite released from NO, (b) the extent of lethality of Cu[DEDTC]₂ is dependent on the reciprocal formation of an inactive ternary Cu[DEDTC]₂NO copper-nitrosyl complex.

The partial molar volumes of indole(Ind) at infinite dilution () in carbon tetrachloride (CCl₄), acetonitrile (ACN) and tetrahydrofuran (THF) as solvents, were estimated from densitometry measurements at 293.15 K. The results indicate that . The values determined in this study are close to the values calculated from reported density for Ind in the solid state. In order to make a comparison the partial molecular volume of benzimidazole (Bim) and benzothiophene (BT) in solvents with appropriate solubility were measured too, and the results have revealed that in CCl₄ and in THF. In this work the role of solvent reorganization around to solute cavity, and specific and nonspecific interactions on the volumetric behavior of these molecules in solution are discussed using the Terasawa-Itsuki-Arakawa model, the Lee-Graziano model, molar volumes of solutes calculated at the DFT-B3LYP/cc-pVTZ and aug-cc-pVTZ level in the gas phase and considering solvent presence with the Onsager’s reaction field, and the van der Waals volume. This analysis suggests that the molecular volumes of solutes are overestimated by the quantum methods employed in this work and that the volumetric contribution from the van der Waals components to the limiting partial molecular volumes of solutes is important, with the exception of Ind in CCl₄ where the solvent reorganization is the dominant factor.

Hankel operators and their symbols, as generalized by V. Pták and P. Vrbová, are considered in the Krein space setting. Under a generic assumption, without which the Krein space case may be untreatable, a necessary and sufficient condition for the existence of Hankel symbols for a given Hankel operator X is given. A parametric labeling of the Hankel symbols of X by means of Schur class functions is obtained. The proof is established by associating to the data of the problem an isometry V acting on a Krein space so that there is a bijective correspondence between the symbols of X and the minimal unitary Hilbert space extensions of V . The result includes uniqueness criteria and a Schur like formula.

Temperature-programmed sulfiding (TPS) and temperature-programmed reduction of the sulfided catalysts (TPR-S) have been employed to evaluate Mo, Fe—Mo, Co—Mo and Ni—Mo carbide catalysts supported on activated carbon (AC). The carbides were prepared by carbothermal hydrogen reduction from co-impregnated precursors, and submitted to presulfiding prior to HDS. Samples of passivated catalysts prepared from the sulfates of Fe and Co contained variable amounts of sulfur, as shown by XPS and elemental analysis, while all samples showed increased sulfur contents after HDS. The TPS traces (up to 400 °C) of the Mo and Co—Mo samples exhibited two H₂S consumption peaks, the first one starting at 100 °C and the second within the 400 °C isothermal region, located immediately after a H₂S production peak centered at 400 °C for Mo and at 340 °C for Co—Mo. The Fe—Mo and Ni—Mo carbides exhibited a broad H₂S consumption signal between 100 and 400 °C. The low temperature signals can be attributed to reduction of Mo(VI) oxide into Mo(V) or Mo(IV) sulfides, while the broad, higher temperature band is assigned to further reduction to the fully sulfided surface species. The TPR-S spectra showed three H₂S evolution peaks, where the area of the first peak (assigned to reduction of sulfur species adsorbed on coordinatively unsaturated edge/corner sites) follows the order Co—Mo » Ni—Mo is approximately equal to Mo greater than Fe—Mo, which fully agrees with the order of HDS activities at steady state. Elemental analysis of the pre-sulfided AC support suggest that a large part of the sulfur consumed in sulfiding the catalysts is retained as elemental sulfur within the microporous structure of the support, although HRTEM observations confirm that MoS₂-like structures are present in these samples. These results reinforce the importance of sulfided surface phases in HDS on carbides of transition metal catalysts.

We introduce here the notion of Koszul duality for monoids in the monoidal category of species with respect to the ordinary product. To each Koszul monoid we associate a class of Koszul algebras in the sense of Priddy, by taking the corresponding analytic functor. The operad of rooted trees enriched with a monoid M was introduced by the author. One special case of that is the operad of ordinary rooted trees, called in the recent literature the permutative non-associative operad. We prove here that is Koszul if and only if the corresponding monoid M is Koszul. In this way we obtain a wide family of Koszul operads, extending a recent result of Chapoton and Livernet, and providing an interesting link between Koszul duality for associative algebras and Koszul duality for operads.

We calculate the tunneling process of a Dirac particle across two square barriers separated by a distance d, as well as the scattering by a double-cusp barrier, where the centers of the cusps are separated by a distance larger than their screening lengths. Using the scattering matrix formalism, we obtain the transmission and reflection amplitudes for the scattering processes of both configurations. We show that the presence of transmission resonances modifies the Lorentzian shape of the energy resonances and induces the appearance of additional maxima in the transmission coefficient in the range of energies where transmission resonances occur. We calculate the Wigner time delay and show how their maxima depend on the position of the transmission resonance.

This work presents the results of ¹³⁷Cs, ⁴⁰K, ²³²Th and ²³⁸U concentration (Bq kg^-1) values in coastal marine sediments collected from 38 sites along the coastline of the island of Margarita, Venezuela. The purpose was to determine baseline values for these radionuclides in surface marine sediments and to detect if there were any anomalously high concentration values. Only three of the 38 sediments analyzed had measurable values above the detection limit of 0.9 Bq kg^-1 for ¹³⁷Cs and the highest only being 1.4 Bq kg^-1. While, the concentration (Bq kg^-1) ranges for the primordial radionuclides, ⁴⁰K, ²³²Th and ²³⁸U were as follows: 12.2—211.7, Less Than 1.5—9.8 and Less Than 4.4—20.7, respectively. These concentration ranges for the primordial radionuclides can be considered as baseline values for surface marine sediments for areas that are considered not polluted by man or contaminated by nature. Finally, the concentration range of ¹³⁷Cs can also be employed as baseline values, which only seem to have been the result of the atmospheric testing of nuclear weapons in the past.

Three H-ZSM5 solids with Si/Al atomic ratios of 22, 71 and 96 were synthesized and characterized by X-ray diffraction (XRD), ICP-AES chemical analysis and nitrogen physisorption at -196 °C. These were employed as supports in the synthesis of Pt/H-ZSM5 catalysts with platinum contents around 1 wt.%, by means of the microwave-assisted polyol method: platinum salt solutions in ethylene glycol were irradiated at powers of 184 and 461 W for time periods of 30 and 60 s in order to obtain Pt nanoparticles suspensions which were mixed with the supports and ultrasonically irradiated for 30 min to obtain the catalysts. This methodology allowed the synthesis of the catalysts efficiently and in relatively short times. Characterization of the catalysts by XRD showed that the ultrasonic irradiation did not affect the support structure. X-ray photoelectron spectroscopy revealed the presence of Pt(0) species on the solids surfaces. Temperature-programmed reduction studies suggested an effect of the time and power of microwave irradiation on the reducibility of the catalysts, i.e., at the shorter times and lower irradiation powers, the reducibility of the platinum species decreases. Catalytic testing through the hydrogenation of toluene indicated that there is an effect of time and power of microwave irradiation on the initial hydrogenation activity of the Pt/H-ZSM5 catalysts. The catalyst prepared from suspensions irradiated at 461 W for 60 s showed the highest activity, which seems to be related to the lower particle size and better dispersion of Pt.

A spin filtering device based on quantum spin interference is addressed, for use with a two-dimensional GaAs/AlGaAs electron gas that has both Rashba and Dresselhaus spin—orbit (SO) couplings and an applied external magnetic field. We propose an experimentally feasible electronic Mach—Zehnder interferometer and derive a map, in parameter space, that determines perfect spin filtering conditions. We find two broad spin filtering regimes: one where filtering is achieved in the original incoming quantization basis, that takes advantage of the purely non-Abelian nature of the spin rotations; and another where one needs a tilted preferential axis in order to observe the polarized output spinor. Both solutions apply for arbitrary incoming electron polarization and energy, and are only limited in output amplitude by the randomness of the incoming spinor state. Including a full account of the beam splitter and mirror effects on spin yields solutions only for the tilted basis, but encompasses a broad range of filtering conditions.

On 11 January 2010, the United Nations inaugurated the International Year of Biodiversity in Berlin. This initiative is timely, because the environmental movement suffers from an imbalance between its sense of urgency and its intensity of activity. Center stage is now occupied by concerns for the physical environment–in particular, climate change, pollution, and depletion of nonrenewable resources. However, if the living world is to be kept in anything approaching a sustainable condition that can adapt to changes, then politicians, government officials, scientists, and the public will need to give biodiversity the urgent attention that they are starting to give to the physical environment.

Gamma irradiation effect over the properties of slow cooled and fast cooled HDPE/LDPE 10/90 blend was studied. The blend and the neat polyethylenes were irradiated at room temperature in the presence of air using the following doses (4.8 kGy/h): 0, 50, 150, 400 and 1000 kGy. Differential scanning calorimetry (DSC) experiments were carried out using the following heating rates: 5, 10 and 20 °C/min. DSC results for the slow and fast cooled blend showed traces with three melting peaks and with increasing irradiation dose two melting peaks were obtained, i.e. the high melting peak shifts toward lower temperatures to merge with the intermediate melting peak into one endotherm. No changes in crystal structure by X-ray diffraction were found as a result of samples irradiation. Radiation crosslinking prevents crystal rearrangements during heating in the DSC. Gel content and melt flow index (MFI) measurements showed that radiation induced a high degree of crosslinking for all samples; gel content values were above 50% and a drop of more than 90% in the MFI was found. Irradiation of slow cooled samples resulted in larger values of gel content and lower MFI values than for fast cooled samples, mainly because of the higher degree of crosslinking for the former.

In the present work a detailed study of the effect of pH, in the range of 0—4.5, over the mesostructure of SBA-15 and catalytic transformation of 1-butene has been carried out. Also, the effect of silica source hydrolysis on the Al incorporation at different pH was studied varying the order of addition of an aluminium salt, before and after hydrolysis. The samples were characterized by SEM, TEM, ICP and N₂ adsorption. The materials showed a highly ordered hexagonal mesostructure for all the pH range studied. A decrease in particle size with increase of pH was observed. Al incorporation was favoured as pH increased; the highest incorporation was obtained at pH 4.5. An important effect of hydrolysis on Al incorporation was observed depending of metal incorporation. Hydrolysis had also an effect on the distribution and strength of the acid sites. The materials with the highest skeletal isomerization selectivity were those synthesized at pH 4.5.

The objective of the present work is to evaluate the compatibilization of composites of polyolefins (high-density polyethylene and polypropylene) with 30 wt.% hydroxyapatite of nanoscale particle size, employing grafted polymers to improve the interaction between phases and hence, the composite's properties. The functionalization of a high-density polyethylene and a polypropylene was performed in solution, employing acrylic acid as the grafting monomer and dicumyl peroxide as the initiator. The grafting degree was determined through volumetric titration. The nanoscale hydroxyapatite was synthesized through a precipitation method using calcium hydroxide and ammonium phosphate. Polyolefin composites were melt-blended in an internal mixer, varying the amount of compatibilizing agent at 4, 6, 8, and 10 phr. The grafting degrees obtained were 0.72 and 0.38 wt% for the high-density polyethylene and polypropylene, respectively. On the other hand, the melt flow rate values of the composites slightly decreased as the grafted polymer contents increased. The crystallinity degree also decreased in the presence of grafted polymers. The incorporation of the compatibilizing agent favored the dispersion and distribution of the hydroxyapatite particles. The Young's modulus and the tensile stress slightly increased in all composites. The values of activation energy decreased with the addition of the grafted polymers, which is attributed to the less thermally stable functionalized polymer, which is prone to thermal degradation at relatively lower temperatures due to the presence of a large content of carboxylic groups. Nonetheless, the activation energy increased with the amount of functionalized polymer incorporated into the composites due to the interaction between components at the polymer/filler interface.

We describe the separation of whole IgG, IgG(T)-less IgG (called here merely IgG) and IgG(T) and the production of Fab and F(ab')₂ fragments. We studied the pharmacokinetics of these immunoglobulins and fragments in rabbits. Both, the isotypes and the whole IgG fragments were purified and/or produced from the same plasma lot from horses hyper immunized against sphingomyelinase D to produce anti-Loxosceles antivenom. The sphingomyelinase D neutralizing ability of the isotypes and their fragments was measured. Fab and F(ab')₂ PK was well described by a tri-exponential kinetics. IgG and IgG(T) PK, however, deviated from the tri-exponential kinetics 120 h after injecting a bolus of the immunotherapeutics. The departure between tri-exponential PK and the experimental data, was shown to be due to a surge of anti-horse antibodies occurring after 120 h, peaking at is approximately equal to 260 h and decaying slowly afterward.

For more than four decades the International Union for the Conservation of Nature (IUCN) has been assessing the global threat status for species and publishing the results in the periodically updated IUCN Red List of threatened species. Additionally, numerous countries have published national lists of threatened species, often based on IUCN criteria and guidelines for application of IUCN Red List criteria at regional levels. To assess how similar, or how different, national red lists are from the global red list, we compared threatened species lists of four countries (Brazil, Colombia, China, and the Philippines) with the 2008 IUCN Red List. We found notable differences falling into three categories: (1) a number of species (an average of 20% of the species pool considered in each of the four countries) have been listed nationally as threatened, but have yet to be globally assessed by IUCN, (2) some species (14% average) are considered globally threatened by IUCN, but are not listed nationally, and (3) a handful of species (2% average) are not considered threatened by IUCN, but are nationally threatened. However, for most species, the threat assessments concur. In other words, most species are either considered threatened both nationally and globally, or else not considered globally threatened and not listed nationally. Such possible comparison between national red lists and IUCN’s Red List is a high priority both for IUCN and for national red listing agencies.

Antigens present in aqueous n-butanolic extracts (BE) of Schistosoma mansoni (Venezuelan JL strain), Schistosoma intercalatum (Cameroon EDEA strain), and Schistosoma haematobium (Yemen strain) adult worm membranes were compared in immunoblot against sera of patients infected with S. mansoni, S. intercalatum, S. haematobium, Schistosoma japonicum, or Schistosoma mekongi looking for similarities (common antigens) and differences (species-specific antigens). About 17 S. mansoni BE polypeptides (M _r ~8 to greater than 80 kDa) were commonly recognized by S. mansoni-infected patient sera from Venezuela, Senegal, and Ethiopia. S. intercalatum-, S. haematobium-, or S. japonicum-infected sera were almost unreactive with S. mansoni BE. Nonetheless, S. mekongi-infected sera weakly cross-reacted with a ~10—15-kDa subset of S. mansoni BE. About 72.7% of S. intercalatum-infected patient sera reacted with a ~19—21-kDa complex in S. intercalatum BE and cross-reacted with a similar complex in S. haematobium BE. Conversely, all S. haematobium-infected patient sera reacted with a ~19—21-kDa complex in S. haematobium BE and cross-reacted with the ~19—21-kDa complex in S. intercalatum BE; S. mansoni- and S. japonicum-infected patient sera did not react with S. intercalatum or S. haematobium BE. Results showed the presence of a common membrane antigen between African schistosome species and species-specific antigens in S. mansoni BE that could be useful to discriminate between species and/or to detect Schistosoma infections.

Dengue virus (DENV) is the causative agent of dengue fever andthe more severe forms of the infection known as dengue haemorrhagicfever and dengue shock syndrome (DHF/DSS). Secondary infectionswith a serotype different from the primary infection are considereda risk factor for the development of DHF/DSS. One explanationfor the increased risk of DHF/DSS development after heterologoussecondary infections is the antibody-dependent enhancement (ADE)hypothesis. This hypothesis postulates that pre-existing non-neutralizingantibodies will form immune complexes with the new serotype-infectingvirus that in turn will have enhanced capacity to infect macrophagesand other Fc receptor (FcR)-bearing cells. Despite the evidencesupporting the ADE hypothesis, the molecular mechanisms of ADEare not fully understood. In this work, we present evidencewhich indicates that intact lipid rafts are required for theADE infection of U937 cells with DENV. Flow cytometry analysisto measure the percentage of infected cells showed that treatmentof differentiated U937 cells with nystatin (30 µgml^—1), filipin (10 µg ml^—1) or ß-methylcyclodextrin (30 mM) significantly reduces (P less than 0.05)the ADE of DENV-4 infection in vitro without any effect on viabilityor the number of FcR-bearing cells. Later cholesterol replenishmentby supplementing treated cell cultures with bovine fetal serumfor 24 h re-established lipid raft integrity and reversedthe alteration of the ADE in vitro (P less than 0.05). Our resultssuggest that ADE of U937 infection by DENV requires the presenceof cholesterol and cholesterol-rich membrane microdomains.

Distal colon absorbs K⁺ through a Na⁺-independent, ouabain-sensitive H⁺/K⁺-exchange, associated to an apical ouabain-sensitive H⁺/K⁺-ATPase. Expression of HKa2, gene associated with this ATPase, induces K⁺-transport mechanisms, whose ouabain susceptibility is inconsistent. Both ouabain-sensitive and ouabain-insensitive K⁺-ATPase activities have been described in colonocytes. However, native H⁺/K⁺-ATPases have not been identified as unique biochemical entities. Herein, a procedure to purify ouabain-sensitive H⁺/K⁺-ATPase from guinea-pig distal colon is described. H⁺/K⁺-ATPase is Mg²⁺-dependent and activated by K⁺, Cs⁺ and NH₄⁺ but not by Na⁺ or Li⁺, independently of K⁺-accompanying anion. H⁺/K⁺-ATPase was inhibited by ouabain and vanadate but insensitive to SCH-28080 and bafilomycin-A. Enzyme was phosphorylated from [³²P]-?-ATP, forming an acyl-phosphate bond, in an Mg²⁺-dependent, vanadate-sensitive process. K⁺ inhibited phosphorylation, effect blocked by ouabain. H⁺/K⁺-ATPase is an a/ß-heterodimer, whose subunits, identified by Tandem-mass spectrometry, seems to correspond to HKa2 and Na⁺/K⁺-ATPase ß1-subunit, respectively. Thus, colonic ouabain-sensitive H⁺/K⁺-ATPase is a distinctive P-type ATPase.

Mediterranean landscapes resulted from complex land uses that produced a mosaic of extensive crops, grasslands, scrublands and scattered woodlands. During the twentieth century the decrease in traditional agriculture triggered a decrease in open habitats and an increase in forests. In the meantime urban centres grew dramatically. Both spread of forest and urban areas have been suspected to participate in the decline of typical Mediterranean bird species and, in general, to cause faunal loss. However, modern cities offer a variety of landscape types and, in the Mediterranean, their value for native bird species has been little assessed. We compared the bird communities from an urban landscape, including built up and natural or semi natural units within the limits of the city of Montpellier, to the bird communities from non-urban habitats (cropland, grassland and woodland) located nearby but away from direct urban influence. Fifty four percent of the bird species recorded in the non-urban habitats also occurred in the urban landscape. On average, estimated species richness in the urban landscape was similar to values obtained for non-urban habitats. Within the urban landscape species richness was lowest in the dense historical centre and highest in the residential areas. The residential areas and urban woods were suitable habitats for most generalist species but also for several more specialized species recorded in the non-urban habitats. Some species actually reached their highest observation frequency in the urban landscape. Urban landscape was least favourable to the same farmland and open-habitat specialists that have been negatively affected by agricultural abandonment in the region. Finally, five of the species common in the urban landscape had an unfavorable conservation status in 2004 in the EU. This study emphasizes that Mediterranean urban areas have the potential to host a diverse native bird community. Finding ways to improve their carrying capacity for the local avifauna might be a worthwhile objective for animal conservation.

Since there is a reported interrelationship between vitamin A and Fe metabolism, and with immunological response, the objective was to evaluate the effect of a single dose of vitamin A administered to preschool children, on Fe and vitamin A nutritional status, anaemia and phagocytic function of neutrophils, 30 d after supplementation. A total of eighty children (sixty-eight supplemented and twelve controls) were supplemented orally with 200 000 IU (60 mg) vitamin A, and evaluated for nutritional, haematological and immunological responses at the beginning of the study and 30 d after supplementation. Parameters studied included Hb, serum ferritin, retinol and Fe concentrations, transferrin saturation, IL-4, interferon-? and phagocityc capacity of neutrophils using non-fluorescent latex microbeads. After supplementation there was a significant increase in Hb concentration ( P = 0·03), mean corpuscular Hb concentration ( P = 0·001) and serum retinol ( P = 0·0078). Prevalences of anaemia and vitamin A deficiency decreased significantly from 17·6 % to 13·2 % and from 25 % to 13·2 %, respectively. Regarding phagocytic function, there was a significant increase in the number of microbeads engulfed by neutrophils ( P Less than 0·05) and no significant changes in cytokine concentrations at 1 month after treatment. A single dose of 200 000 IU (60 mg) vitamin A administered orally to a group of preschool children with a high prevalence of vitamin A deficiency enhanced serum retinol and Hb concentrations, decreased the prevalence of anaemia and vitamin A deficiency and improved the constitutive phagocytic capacity of neutrophils. Vitamin A supplementation could help to decrease vitamin A deficiency, anaemia prevalence and to improve the innate immunity response in preschool children. The effects were obtained without Fe supplementation.

The title compound, C23H22N2, was obtained using the threecomponent imino Diels—Alder reaction via a one-pot condensation between anilines, -pyridinecarboxyaldehyde and indene using BF3OEt2 as the catalyst. The molecular structure reveals the cis-form as the unique diastereoisomer.The crystal structure comprises one-dimensional zigzag ribbons connected via N–HN hydrogen bonds. C–H%4 interactions also occur

Based in part on the previous version of this Encyclopedia of Life Sciences (ELS) article, Eicosanoid Biosynthesis by Ana Z Fernandez, Mahendra Kuramar Jain and Rafael Apitz-Castro

Eicosanoids are the major products derived from the cellular metabolism of arachidonic acid by the enzymes cyclooxygenase, lipoxygenase and epoxygenases. The eicosanoids comprise several compounds, which include prostaglandins, thromboxanes, prostacyclins, leukotrienes, lipoxins and epoxyeicosatrienoic acids. They represent the major group of metabolically active lipids, exerting their functions through different mechanisms, that is by receptor binding and intracellular signalling pathway modulation. Their effects are diverse, acting on every cell of the body, with a short half-life. A tight regulation on the processes of formation and inactivation or clearance is fundamental to prevent the exacerbation of their effects. Although initially they were strictly linked to inflammatory processes, recent evidences point out their homeostatic counterpart. Thus, there are eicosanoids involved in vasoconstriction/vasodilatation balance, thrombotic/antithrombotic balance and inflammation/anti-inflammation balance. This article will focus on the enzymes involved in the formation of these lipids.

Dwarf mangroves on peat substrate growing in eastern Puerto Rico (Los Machos, Ceiba State Forest) were analyzed for element concentration, leaf sap osmolality, and isotopic signatures of C and N in leaves and substrate. Mangrove communities behind the fringe presented poor structural development with maximum height below 1.5 m, lacked a main stem, and produced horizontal stems from which rhizophores developed. This growth form departs from other dwarf mangrove sites in Belize, Panama, and Florida. The dwarf mangroves were not stressed by salinity but by the low P availability reflected in low P concentrations in adult and senescent leaves. Low P availability was associated with reduced remobilization of N and accumulation of K in senescent leaves, contrasting with the behavior of this cation in terrestrial plants. Remobilization of N and P before leaf abscission on a weight basis indicated complete resorption of these nutrients. On an area basis, resorption was complete for P but not for N. Sulfur accumulated markedly with leaf age, reaching values up to 400%, compared with relatively modest accumulation of Na (40%) in the same leaves. This suggests a more effective rejection of Na than sulfate at the root level. Dwarf mangrove leaves had more positive d¹³C values, which were not related to salinity, but possibly to drought during the dry season due to reduced flooding, and/or reduced hydraulic conductance under P limitation. Negative leaf d¹⁵N values were associated with low leaf P concentrations. Comparison with other R. mangle communities showed that P concentration in adult leaves below 13 mmol kg^-1 is associated with negative d¹⁵N values, whereas leaves with P concentrations above 30 mmol kg^-1 in non-polluted environments had positive d¹⁵N values.

We introduce here the notion of Koszul duality for monoids in the monoidal category of species with respect to the ordinary product. To each Koszul monoid we associate a class of Koszul algebras in the sense of Priddy, by taking the corresponding analytic functor. The operad AM of rooted trees enriched with a monoid M was introduced by the author many years ago. One special case of that is the operad of ordinary rooted trees, called in the recent literature the permutative non associative operad. We prove here that AM is Koszul if and only if the corresponding monoid M is Koszul. In this way we obtain a wide family of Koszul operads, extending a recent result of Chapoton and Livernet, and providing an interesting link between Koszul duality for associative algebras and Koszul duality for operads.

A systematic improvement of parametric quantum methods (PQM) is performed by considering: (a) a new application of parameterization procedure to PQMs and (b) novel parametric functionals based on properties of elementary parametric functionals (EPF) [Ruette et al., Int J Quantum Chem 2008, 108, 1831]. Parameterization was carried out by using the simplified generalized simulated annealing (SGSA) method in the CATIVIC program. This code has been parallelized and comparison with MOPAC/2007 (PM6) and MINDO/SR was performed for a set of molecules with CC, CH, and HH bonds. Results showed better accuracy than MINDO/SR and MOPAC-2007 for a selected trial set of molecules.

We report the isolation and sequencing of CHS3, a gene that encodes one of several chitin synthases in Paracoccidioides brasiliensis, a medically important fungus restricted geographically to Latin America. The gene contains a single open reading frame of 3817 bp with two introns (71 and 86 bp) and encodes a 1220 amino acid polypeptide with high similarity to other fungal chitin synthases. Northern analysis reveals a high expression of CHS3 in the pathogenic yeast-like phase of the fungus and at the end of the mycelium-yeast transition. Expression of P. brasiliensis CHS3 in a Saccharomyces cerevisiae chs3 null mutant enhanced calcofluor white staining in parallel to an increase in total chitin synthase activity and chitin content in its cell wall. The sequence of P. brasiliensis CHS3 is available at the GenBank database under Accession No.

Human NK cells are classified into two populations according to the intensity of CD56 surface expression, as well as possession of CD16, FcRIII. CD56^dimCD16^bright make up 90% circulating NK cells, whereas CD56^brightCD16^-/dim comprises the remaining 10%. Here we report that peripheral NK cells upon CD16 cross-linking up-regulates the expression of activating markers and receptors such as CD25, CD69, NKp44, NKp30, CD40L and the intensity of CD56 expression. Additionally, co-culturing immature DCs with CD16 activated NK cells was found to significantly increase the expression of maturation markers on DCs. These results suggest that CD16 cross-linking on resting peripheral blood NK cells triggers the activation of these cells and induces the appearance of CD56^bright NK cells. The latter were found capable of producing pro-inflammatory cytokines, IFN-? and TNF-a and notably IL-12.

In the present work a detailed study of the effect of pH, in the range of 0—4.5, over the mesostructure of SBA-15 and catalytic transformation of 1-butene has been carried out. Also, the effect of silica source hydrolysis on the Al incorporation at different pH was studied varying the order of addition of an aluminium salt, before and after hydrolysis. The samples were characterized by SEM, TEM, ICP and N₂ adsorption. The materials showed a highly ordered hexagonal mesostructure for all the pH range studied. A decrease in particle size with increase of pH was observed. Al incorporation was favoured as pH increased; the highest incorporation was obtained at pH 4.5. An important effect of hydrolysis on Al incorporation was observed depending of metal incorporation. Hydrolysis had also an effect on the distribution and strength of the acid sites. The materials with the highest skeletal isomerization selectivity were those synthesized at pH 4.5.

Gamma irradiation effect over the properties of slow cooled and fast cooled HDPE/LDPE 10/90 blend was studied. The blend and the neat polyethylenes were irradiated at room temperature in the presence of air using the following doses (4.8 kGy/h): 0, 50, 150, 400 and 1000 kGy. Differential scanning calorimetry (DSC) experiments were carried out using the following heating rates: 5, 10 and 20 °C/min. DSC results for the slow and fast cooled blend showed traces with three melting peaks and with increasing irradiation dose two melting peaks were obtained, i.e. the high melting peak shifts toward lower temperatures to merge with the intermediate melting peak into one endotherm. No changes in crystal structure by X-ray diffraction were found as a result of samples irradiation. Radiation crosslinking prevents crystal rearrangements during heating in the DSC. Gel content and melt flow index (MFI) measurements showed that radiation induced a high degree of crosslinking for all samples; gel content values were above 50% and a drop of more than 90% in the MFI was found. Irradiation of slow cooled samples resulted in larger values of gel content and lower MFI values than for fast cooled samples, mainly because of the higher degree of crosslinking for the former

Three H-ZSM5 solids with Si/Al atomic ratios of 22, 71 and 96 were synthesized and characterized by X-ray diffraction (XRD), ICP-AES chemical analysis and nitrogen physisorption at -196 °C. These were employed as supports in the synthesis of Pt/H-ZSM5 catalysts with platinum contents around 1 wt.%, by means of the microwave-assisted polyol method: platinum salt solutions in ethylene glycol were irradiated at powers of 184 and 461 W for time periods of 30 and 60 s in order to obtain Pt nanoparticles suspensions which were mixed with the supports and ultrasonically irradiated for 30 min to obtain the catalysts. This methodology allowed the synthesis of the catalysts efficiently and in relatively short times. Characterization of the catalysts by XRD showed that the ultrasonic irradiation did not affect the support structure. X-ray photoelectron spectroscopy revealed the presence of Pt(0) species on the solids surfaces. Temperature-programmed reduction studies suggested an effect of the time and power of microwave irradiation on the reducibility of the catalysts, i.e., at the shorter times and lower irradiation powers, the reducibility of the platinum species decreases. Catalytic testing through the hydrogenation of toluene indicated that there is an effect of time and power of microwave irradiation on the initial hydrogenation activity of the Pt/H-ZSM5 catalysts. The catalyst prepared from suspensions irradiated at 461 W for 60 s showed the highest activity, which seems to be related to the lower particle size and better dispersion of Pt.

We describe the separation of whole IgG, IgG(T)-less IgG (called here merely IgG) and IgG(T) and the production of Fab and F(ab')₂ fragments. We studied the pharmacokinetics of these immunoglobulins and fragments in rabbits. Both, the isotypes and the whole IgG fragments were purified and/or produced from the same plasma lot from horses hyper immunized against sphingomyelinase D to produce anti-Loxosceles antivenom. The sphingomyelinase D neutralizing ability of the isotypes and their fragments was measured. Fab and F(ab')₂ PK was well described by a tri-exponential kinetics. IgG and IgG(T) PK, however, deviated from the tri-exponential kinetics 120 h after injecting a bolus of the immunotherapeutics. The departure between tri-exponential PK and the experimental data, was shown to be due to a surge of anti-horse antibodies occurring after 120 h, peaking at ˜ 260 h and decaying slowly afterward

The title compound, C₂₃H₂₂N₂, was obtained using the three-component imino Diels-Alder reaction via a one-pot condensation between anilines, -pyridinecarboxyaldehyde and indene using BF₃·OEt₂ as the catalyst. The molecular structure reveals the cis-form as the unique diastereoisomer. The crystal structure comprises one-dimensional zigzag ribbons connected via N-HN hydrogen bonds. C-H interactions also occur

The rates of gas-phase elimination of trimethyl orthovalerate and trimethyl orthochloroacetate have been determined in a static system, and the reaction Pyrex vessels have been deactivated with the product of decomposition of allyl bromide. The reactions are unimolecular and follow a first-order rate law. The working temperature and pressure ranges were 313-410 °C and 40-140 Torr, respectively. The rate coefficients for the homogeneous reaction are given by the following Arrhenius expressions: for trimethyl orthovalerate: log k (s^-1) = [(14.00 ± 0.28) - (196.3 ± 1.7) (kJ/mol)] (2.303RT)^-1, (r = 0.9999); and for trimethyl orthochloroacetate: log k (s^-1) = [(13.54 ± 0.21) - (209.3 ± 1.9)(kJ/mol)](2.303RT)^-1, (r = 0.9998). The theoretical calculations of the kinetic and thermodynamic parameters were carried out by using B3LYP, B3PW91, MPW1PW91, and PBEPBE methods. The theoretical results show reasonably good agreement with the experimental energy and enthalpy of activation values when using the B3PW91/6-31++G** method for trimethyl orthovalerate and PBEPBE /6-31++G** for trimethyl orthochloroacetate. These calculations suggest a molecular concerted nonsynchronous mechanism where C-OCH₃ bond polarization, in the sense C^d+···^d-OCH₃, is the rate-determining step. The increase in electron density of the oxygen atom at OCH₃ eases the abstraction of the hydrogen of the adjacent C-H bond in a four-membered cyclic structure to give methanol and the corresponding unsaturated ketal. The electron-donor substituent enhances decomposition rates by stabilizing the positive charge developing in the transition state at the carbon bearing the three methoxy groups, whereas the electron-withdrawing substituent destabilizes this charge, thus retarding the reaction.

The use of PMMA as dental and osseous cement and also in the fabrication of intraocular lenses has been widely reported. The combination of its excellent properties with those of hydroxyapatite (HA) to form a composite material, can result in very interesting properties as a biomaterial. The key is to obtain a good filler dispersion and interface bonding. Ultrasonic radiation seems to be a very versatile method for the synthesis of these materials, since the use of conventional initiators can be avoided, the filler dispersion improved and the interface interaction can be promoted. In the present work PMMA/HA composite materials were prepared by three different synthesis routes using ultrasonic radiation, in order to study the effect of the synthesis method on the final microstructure. Method I: in situ synthesis of PMMA and HA, under ultrasonic radiation by emulsion polymerization of MMA and HA precursors. Method II: in situ synthesis of HA, (from its precursors) by high frequency ultrasound in commercial PMMA solution Method III: in situ polymerization of MMA under high frequency ultrasonic radiation and adding HA to the solution and Method IV Mixing of hydroxyapatite nanocrystals, in different proportions, in a solution of commercial PMMA, by different periods from 10 min to 7 h, under low frequency (conventional) ultrasonic radiation, to compare the effect of high frequency and conventional ultrasound radiation. The different materials were characterized by FTIR, SEM, TEM, DRX, ¹H NMR and TGA. The results showed that, all the composites prepared by in situ synthesis showed an interaction between HA and PMMA, manifested by a bonding of the phosphate groups with the polar groups of the polymer matrix observed by FTIR. On the other hand, when the synthesis was carried out simultaneously adding HA and PMMA precursors a inhibition of the polymerization reaction of MMA was observed.

Distal colon absorbs K⁺ through a Na⁺-independent, ouabain-sensitive H⁺/K⁺-exchange, associated to an apical ouabain-sensitive H⁺/K⁺-ATPase. Expression of HKa2, gene associated with this ATPase, induces K⁺-transport mechanisms, whose ouabain susceptibility is inconsistent. Both ouabain-sensitive and ouabain-insensitive K⁺-ATPase activities have been described in colonocytes. However, native H⁺/K⁺-ATPases have not been identified as unique biochemical entities. Herein, a procedure to purify ouabain-sensitive H⁺/K⁺-ATPase from guinea-pig distal colon is described. H⁺/K⁺-ATPase is Mg²⁺-dependent and activated by K⁺, Cs⁺ and NH₄⁺ but not by Na⁺ or Li⁺, independently of K⁺-accompanying anion. H⁺/K⁺-ATPase was inhibited by ouabain and vanadate but insensitive to SCH-28080 and bafilomycin-A. Enzyme was phosphorylated from [³²P]-?-ATP, forming an acyl-phosphate bond, in an Mg²⁺-dependent, vanadate-sensitive process. K⁺ inhibited phosphorylation, effect blocked by ouabain. H⁺/K⁺-ATPase is an a/ß-heterodimer, whose subunits, identified by Tandem-mass spectrometry, seems to correspond to HKa2 and Na⁺/K⁺-ATPase ß1-subunit, respectively. Thus, colonic ouabain-sensitive H⁺/K⁺-ATPase is a distinctive P-type ATPase

For more than four decades the International Union for the Conservation of Nature (IUCN) has been assessing the global threat status for species and publishing the results in the periodically updated IUCN Red List of threatened species. Additionally, numerous countries have published national lists of threatened species, often based on IUCN criteria and guidelines for application of IUCN Red List criteria at regional levels. To assess how similar, or how different, national red lists are from the global red list, we compared threatened species lists of four countries (Brazil, Colombia, China, and the Philippines) with the 2008 IUCN Red List. We found notable differences falling into three categories: (1) a number of species (an average of 20% of the species pool considered in each of the four countries) have been listed nationally as threatened, but have yet to be globally assessed by IUCN, (2) some species (14% average) are considered globally threatened by IUCN, but are not listed nationally, and (3) a handful of species (2% average) are not considered threatened by IUCN, but are nationally threatened. However, for most species, the threat assessments concur. In other words, most species are either considered threatened both nationally and globally, or else not considered globally threatened and not listed nationally. Such possible comparison between national red lists and IUCN’s Red List is a high priority both for IUCN and for national red listing agencies

This study describes the aluminum (Al) accumulation in relation to macronutrient and micronutrient elements in 19 Melastomataceae species in the Guayana Region in Venezuela. The purpose was to investigate the Al accumulation in four tribes and different life forms. Aluminum accumulation was predicted in the basal tribes Miconieae and Merianieae in contrast to the derived tribes and herbs from any tribe, which generally do not accumulate Al. The survey was done in a vegetation continuum, which includes a savanna shrubland, a palm-swamp community, and an evergreen forest in the Guayana region in southeastern Venezuela. The highest value of soil Al concentration was found in the savanna shrubland, where ten lignified Miconiae and one Merianeae Al accumulators were present. At the forest, the site with highest soil acidity, four Al-accumulator tree species from Miconiae were found. Miconia lepidota showed similar Al foliar concentrations in the savanna shrubland and forest, but foliar Ca was lower in the forest, even though it was the site with highest Ca in the soil. At the palm-swamp community, the Melastomeae shrub Macairea pachyphylla was found with an Al concentration of 0.59 g kg^-1 in leaves and 0.16 g kg^-1 in bark. At the same site, Al accumulation occurred in one Microlicieae species, one Miconieae species, and in the Melastomeae herbs Pterogastra divaricata (13.25 g [kg dry mass]^-1) and Pterolepis trichotoma (17.83 g kg^-1). The report of Al hyperaccumulation in P. trichotoma is new for the genus, and Al accumulation in herbs is considered exceptional. The foliar Al concentration was positively correlated (p %26lt; 0.005) with Fe (r = 0.64, n = 20) and Zn (r = 0.63). The analysis of the relationships between soil Al, Fe, or Zn and the concentrations of these elements in leaves revealed they were not significantly correlated. The results indicate Al hyperaccumulation in two herbaceous Melastoamataceae species and suggest Al accumulation in this life form deserves future research. However, they also confirm the highest number of Al accumulators in lignified species of the ancient tribe Miconiae (14 out of 19 species studied).

A critical review of the development of specific chemotherapeutic approaches for the management of American Trypanosomiasis or Chagas disease is presented, including controversies on the pathogenesis of the disease, the initial efforts that led to the development of currently available drugs (nifurtimox and benznidazole), limitations of these therapies and novel approaches for the development of anti-Trypanosoma cruzi drugs, based on our growing understanding of the biology of this parasite. Among the later, the most promising approaches are ergosterol biosynthesis inhibitors such as posaconazole and ravuconazole, poised to enter clinical trials for chronic Chagas disease in the short term; inhibitors of cruzipain, the main cysteine protease of T. cruzi, essential for its survival and proliferation in vitro and in vivo; bisphosphonates, metabolic stable pyrophosphate analogs that have trypanocidal activity through the inhibition of the parasite's farnesyl-pyrophosphate synthase or hexokinase; inhibitors of trypanothione synthesis and redox metabolism and inhibitors of hypoxanthine-guanine phosphoribosyl-transferase, an essential enzyme for purine salvage in T. cruzi and related organisms.Finally, the economic and political challenges faced by development of drugs for the treatment of neglected tropical diseases, which afflict almost exclusively poor populations in developing countries, are analyzed and recent potential solutions for this conundrum are discussed.

Lepidoptera es un orden de insectos con más de 180,000 especies descritas en el ámbito mundial, con estadios larvales de mariposas conocidas como orugas parecidas a gusanos. Cerca de 12 familias de mariposas alrededor del mundo son capaces de causar lesiones graves que van desde una dermatitis hasta la insuficiencia renal, incluyendo alteraciones de la hemostasia, fallo respiratorio y síntomas neurotóxicos. Estas orugas están cubiertas de largas cerdas, parecidas a pelos, que contienen veneno y lo usan para protegerse contra sus predadores. La cerda causa una reacción dolorosa, debido a la presencia de neurotoxinas. Estas orugas se encuentran ampliamente esparcidas en Norteamérica y a menudo durante las estaciones seca y lluviosa, en regiones tropicales, pudiendo crear 2 generaciones de larvas al año. Existen varias especies de estas orugas, sin embargo, Megalopyge opercularis es la especie más extensamente distribuida en América Latina y los Estados Unidos. Este trabajo refiere, a nuestra revisión de la literatura, el primer caso descrito de envenenamiento por el “Gusano-pollo" (Megalopyge opercularis) en Venezuela. El caso en estudio presentó síntomas muy severos, incluyendo las reacciones sistémicas, así como dolor intenso en la mano, irradiado a la parte alta del miembro, edema restringido, cefalea, mareos, opresión retroesternal y síntomas parecidos al choque, que requirieron su hospitalización. La sintomatología mejoró con opiáceos y analgésicos fuertes.

Lepidoptera is a large order of insects, with more than 180,000 species word-wide, showing larval stages of butterflies andmoths known as wormlike caterpillars. Almost 12 families of butterflies around the world are capable of causing severe human injuries, varying from dermatitis, renal failure, hemostatic alterations, respiratory failure and neurotoxic symptoms. These caterpillars are coated in long, hair-like setae containing venom to protectthemselves against aggressive predators. The setae cause a painful reaction, upon contact, due to presence of neurotoxins. These caterpillars are extensively dispersed all through North America and often, during the dry and wet seasons in tropical regions, being able to sustain two annual larval generations. There exist several species of Megalopyge caterpillars; however, Megalopyge opercularis is the most widely distributed species in Latin America and the United States. This work reports, to our knowledge, the first case of envenomation by the “gusano-pollo” (Megalopyge opercularis), a stinging caterpillar, described in Venezuela. The patient in this report presented severesymptoms, including systemic reactions such as intense hand pain irradiated to the upper arm, restricted swelling, headache, dizziness, serious chest distress and shock-likesymptoms that required hospitalization. Symptoms improved upon treatment with opiaceous analgesic drugs.

In this paper, we describe a general approach to solving evolution equations for probability densities using interacting trajectory ensembles. Assuming the existence of a positive definite (probabilistic) description of the state of the system, we derive general equations of motion for the trajectories in the kinematic space (e.g., configuration or phase space). The vector field describing the time rate of change of the trajectory ensemble members depends, in general, on both external forces and on the probability density itself. The dependence of the equations of motion on the probability density lead to interactions between the ensemble members and a loss of their statistical independence. The formalism is illustrated by a number of numerical examples. For multidimensional systems, a gauge-like freedom exists in the choice of the underlying vector field, which leaves the evolution of the probability density invariant

Hydrogen adsorption in gold nanocontact electrodes in electrochemical solution is experimentally discerned. This is performed with gold nanocontact conductance histograms in an electrochemical environment in which both the electrochemical potential and the electrolyte type are varied. Different salts, acids, and hydrogen peroxide electrolytes are studied. Salts and acids exhibit at negative electrochemical potentials different fractional quantum conductance histograms peaks associated to extra stable structures due to H adsorption while these peaks do not appear for H₂O₂ where electron transfer between solution and electrodes occurs without hydrogen formation or hydrogen adsorption on the gold electrode

Las especies del género Lantana son conocidas por el alto valor comercial de sus aceites naturales, pero se sabe poco de su respuesta fotosintética a variables ambientales. El efecto del déficit hídrico sobre la actividad fotosintética se estudió en tres especies de Lantana: L. caracasana, L. canescens y L. camara, con tratamientos de suspensión del riego. L. caracasana tuvo la mayor asimilación de carbono durante el período de medida y el déficit en la disponibilidad de agua ocasionó una disminución del potencial hídrico, de la fotosíntesis y de la conductancia estomática en las tres especies. Los cambios observados en las variables de fluorescencia, en la eficiencia cuántica aparente y en la fotosíntesis a luz saturante, sugieren una regulación descendente de la actividad fotoquímica del fotosistema II durante el déficit hídrico. En plantas control se observaron pocas diferencias entre especies en la respuesta de la fotosíntesis a la concentración intercelular de CO2. La temperatura óptima para la fotosíntesis varió entre 25-26ºC. El efecto del déficit hídrico sobre el intercambio gaseoso de las tres especies fue diferente, siendo L. camara la más afectada.

The species of the Lantana genus are known by the high commercial value of its natural oils, but their photosynthetic response to environmental variables is not well known. To characterize the photosynthetic capacity and establish the effect of water deficit on photosynthesis, plants of three Lantana species (L. caracasana, L. canescens and L. camara) were submitted to water deficit by holding watering.The highest diurnal carbon assimilation was observed in L. caracasana and water deficit caused a decline in water potencial, photosynthesis and stomatal conductance of all species. Changes observed in variable fluorescence, apparent quantum yield and photosynthesis at saturated light, suggested a down regulation of photochemical activity of photosystem II during water deficit. In well irrigated plants, slight differences were observed among species in the photosynthetic response to intercellular CO2 concentration. Optimum temperature of photosynthesis was within 25-26ºC. The effect of water deficit on the photosynthetic parameters varied with the species, being L. camara the most affected.

Soil samples were collected in six South American countries in a total of 71 different 1 ha forest plots across the Amazon Basin as part of the RAINFOR project. They were analysed for total and exchangeable cations, C, N, pH with various P fractions also determined. Physical properties were also examined and an index of soil physical quality proposed. A diverse range of soils was found. For the western areas near the Andean cordillera and the southern and northern fringes, soils tend to be distributed among the lower pedogenetic levels, while the central and eastern areas of Amazonia have more intensely weathered soils. This gives rise to a large variation of soil chemical and physical properties across the Basin, with soil properties varying predictably along a gradient of pedogenic development. Nutrient pools generally increased slightly in concentration from the youngest to the intermediate aged soils after which a gradual decline was observed with the lowest values found in the most weathered soils. Soil physical properties were strongly correlated with soil fertility, with favourable physical properties occurring in highly weathered and nutrient depleted soils and with the least weathered, more fertile soils having higher incidence of limiting physical properties. Soil phosphorus concentrations varied markedly in accordance with weathering extent and appear to exert an important influence on the nitrogen cycle of Amazon forest soils.

The kinetics and mechanisms of the gas-phase elimination reaction of several alkyl and (dimethylamino)alkyl acetates were studied by means of electronic structure calculations using MP2/6-31G(d,p) and DFT B3LYP/6-31G(d,p), B3LYP/6-31++G(d,p), MPW1PW91/6-31G(d,p), MPW1PW91/6-31++G(d,p), PBEPBE/6-31G(d,p), PBEPBE/6-31++G(d,p) level of theory. Theoretical calculations demonstrated that ethyl acetate, 2-(dimethylamino)ethyl acetate, propyl acetate, 3-(dimethylamino)propyl acetate, and butyl acetate decompositions proceed through a concerted six-membered cyclic transition state to give acetic acid and the corresponding olefin. Conversely, an alternative path occurs for 4-(dimethylamino)butyl acetate, where a late transition state structure resembles the products N-methylpyrrolidine and methyl acetate. The observed products and the nature of the TS suggest that the nitrogen atom assists the elimination of the acetate. An intimate ion-pair intermediate has been considered, followed by decomposition to the final products methyl acetate and N-methyl pyrrolidine. The high reaction rate observed in 4-(dimethylamino)butyl acetate when compared to the parent compound is discussed. The nature of these reactions is examined in terms of geometrical parameters, electron distribution, and bond order analysis.

The crystallization kinetics and morphology of biodegradable and double crystalline poly(l-lactide)-b-poly(e-caprolactone) diblock copolymers (PLLA-b-PCL) was studied in a wide composition range by differential scanning calorimetry (DSC) and polarized light optical microscopy (PLOM). The two blocks were found to be partially miscible according to the variations of their thermal transitions with composition. PLOM results showed that PLLA crystallizes in a wide composition range with a spherulitic superstructural morphology. Only when the PLLA content is as low as 10 wt % are axialites formed. These results were in good agreement with the overall crystallization kinetics obtained by DSC isothermal experiments and analyzed by the Avrami equation. Both overall crystallization rates and spherulitic growth rates of the PLLA block decrease with PCL content because PCL acts as a diluent for the PLLA block in view of their miscibility. Reorganization processes revealed as double melting peaks for the PLLA block (not observed for the PLLA homopolymer) were observed during heating scans performed after isothermal crystallization. The reorganization ability of the PLLA block was found to increase with PCL content, a fact that quantified the perturbation caused by molten PCL block chains during the isothermal crystallization of the PLLA block. The PCL block crystallizes within previously formed PLLA spherulites or axialites. Despite the partial miscibility, unexpected and novel fractionated crystallization of the PCL occurs at contents of PCL between 40 and 19 wt %. For the lowest PCL content (i.e., 19%), a homogeneous nucleation process was detected, as indicated by the large supercooling needed for crystallization and by the first-order crystallization kinetics obtained (i.e., Avrami index close to 1). Because of the partial miscibility, the glass-transition temperature of the PLLA block (T_g,PLLA) decreases with PCL addition, so at PCL contents lower than 40 wt %, the T_g,PLLA values are close to or higher than the crystallization temperature of the PCL block. Therefore, PCL fractionated crystallization is induced by hard confinement of the PLLA amorphous and crystalline regions. This is the first time that a homogeneous nucleation process has been documented for a crystallizable component in a miscible or weakly segregated diblock copolymer. The PCL block can also be nucleated by previously formed PLLA crystals depending on the crystallization degree of the PLLA, which was varied by self-nucleation experiments. The crystallization rate of PCL strongly decreased with increasing PLLA content.

The role of calcium and its relevance have been deeply revised with respect to trypanosomatids, as the mechanism by which calcium enters trypanosomes was, until now, not well understood. There is evidence supporting the presence of a nAChR in another member of the trypanosomatidae family, Trypanosoma cruzi, these receptors being one entry path to calcium ions. The aims of this work were to determine if there was a nicotinic acetylcholine receptor (nAChR) in Trypanosoma evansi, and to subsequently perform a partial pharmacological characterization of this receptor. After being loaded with FURA-2AM, individual cells of T. evansi, were exposed to cholinergic compounds, and the cells displayed a dose-dependent response to carbachol. This observation indicated that a cholinergic receptor may be present in T. evansi. Although a dose-dependent response to muscarine could not be demonstrated, nicotine could promote an incremental dose-dependent response. The relative potency of this specific agonist of nAChR is in agreement with previous reports. The estimated affinity values were a K_d1 value of 29.6 ± 5.72 nM and a K_d2 value of 315.9 ± 26.6 nM, which is similar to the K_d value reported for the a4 nicotinic receptor. The Hill coefficients were determined to be an n₁ of 1.2 ± 0.3 and an n₂ of 4.2 ± 1.3. Finally, our calculations indicated that there are about 1020 receptors in each T. evansi parasite, which is approximately 15-fold lower than the number reported in Torpedo californica electric cells. These results suggest the presence of a nAChR in T. evansi, which is able to bind nicotinic ligands and induce calcium signals.

Pseudochondrostoma duriense and Achondrostoma oligolepis are two Iberian endemic cyprinid fish species that occur in sympatry over most of their distribution range and that are suspected to hybridize in nature. Here, we employed a combination of mitochondrial and microsatellite markers to explore the extent of introgressive hybridization between these fishes. Two natural hybrid zones were identified in different river basins. Introgression was bi-directional and both hybrid zones consisted mostly of parental genotypes/phenotypes (i.e. bimodal hybrid zones). Yet, they appeared to differ in the extent and direction of introgression, which supports the view that they constitute independent outcomes of different hybridization processes probably influenced by environmental features. Several discordances were found between mtDNA and microsatellite results, suggesting that this hybridization process has complex consequences and illustrating the importance of using independent markers to define accurately the hybrid status of individuals in the presence of high levels of backcrossing.

Helicobacter spp. occur in the digestive system of a broad rangeof animal taxa, including marine mammals. Only one formallyrecognized species, Helicobacter cetorum, has been describedin marine mammals. Helicobacter has not been reported in theAtlantic spotted dolphin (Stenella frontalis). The purpose ofour study was to examine the digestive tract of a stranded spotteddolphin for Helicobacter. Tissue and content samples were collectedat necropsy and examined by histopathology and molecular analysesusing Helicobacter genus-specific 16S rDNA polymerase chainreaction (PCR) and DNA sequencing. Helicobacter was detectedin all stomach divisions and the duodenal ampulla. A sequencetype of the 16S rRNA gene shared a 98—99% identity tosequences from H. cetorum. This study reports for the firsttime Helicobacter in S. frontalis.

We report the isolation and sequencing of CHS3, a gene that encodes one of several chitin synthases in Paracoccidioides brasiliensis, a medically important fungus restricted geographically to Latin America. The gene contains a single open reading frame of 3817 bp with two introns (71 and 86 bp) and encodes a 1220 amino acid polypeptide with high similarity to other fungal chitin synthases. Northern analysis reveals a high expression of CHS3 in the pathogenic yeast-like phase of the fungus and at the end of the mycelium-yeast transition. Expression of P. brasiliensis CHS3 in a Saccharomyces cerevisiae chs3 null mutant enhanced calcofluor white staining in parallel to an increase in total chitin synthase activity and chitin content in its cell wall. The sequence of P. brasiliensis CHS3 is available at the GenBank database under Accession No.

We analyzed the distributional pattern of species and environmental gradients across inland water—land palm ecotones (morichals) of the Orinoco lowlands to increase comprehension of the nature of ecotone heterogeneity. A total of 91 species (53 genera and 45 families) with aboveground phytomass %26gt; 0.1 g dry mass were recorded. Detrented canonical correspondence analysis (DCCA) indicated that vegetation phytomass was related strongly to soil properties, including gradients of silt (14.5—4.7%), exchangeable Al (1.05—3.10 cmole kg^-1), K (0.03—0.30 cmole kg^-1), Na (0.01—0.08 cmole kg^-1), Mg (0.03—0.54 cmole kg^-1) concentrations, pH (3.7—5.0 units), and soil organic matter. Cluster analysis allowed the definition of four types of ecotones on the basis of hydrogeomorphic processes. The first major group (1) encompassing the sites from Venezuelan lowlands (i.e., 3V, 4V, 5V, 6V, and 7V) was related to less acidic soils with high organic matter content. The second group (II) from Eastern Colombian llanos (i.e., sites 8C, 9C, 11C, 12C, 13C, 14C, and 15C) was located in acidic soils (3.9—4.5 units) with high Mg concentration. The third group (III) (i.e., sites IV and 10C) was located in soils with high Na content, whereas the fourth group (IV) (i.e., site 2V) was characterized by species growing in soils with low exchangeable aluminum. The results evidenced the interactive role of valley constraint, landforms, hydrological regime, and soil feature in structuring the plant community. Biogeographic and floristic considerations were also taken into account to explain differences in species composition.

A low-cost, automated apparatus has been used to perform micrometric deposition of small pendant drops onto a quiet liquid surface. The approach of the drop to the surface is obtained by means of discrete, micron-scale translations in order to achieve deposition at adiabatically zero velocity. This process is not only widely used in scientific investigations in fluid mechanics and thermal sciences but also in engineering and biomedical applications. The apparatus has been designed to produce accurate deposition onto the surface and minimize the vibrations induced in the drop by the movement of the capillary tip. Calibration tests of the apparatus have shown that a descent of the drop by discrete translational steps of ~ 5.6 µ m and duration of 150—200 ms is sufficient to minimize its penetration depth into the liquid when it touches the surface layer and reduce to a level of noise the vibrations transmitted to it by the translation of the dispenser. Different settings of the experimental setup can be easily implemented for use in a variety of other applications, including deposition onto solid surfaces, surface tension measurements of pendant drops, and wire bonding in microelectronics

Two equivalents of the chiral dibenz[b,f]azepine-derived P-alkene ligands 2-6 per metal afforded mononuclear Rh(I) and Cu(I) complexes that were used as catalysts for asymmetric conjugate addition reactions. Rh formed square-planar neutral (8-10) and cationic complexes (11, 12) of the general formulas [RhCl(?¹P-alkene)(?²P-alkene)] and cis-[Rh(?²P-alkene)₂][BF₄], respectively (P-alkene = 2, 5, 6). In both cases reversible decoordination of the alkene function of the bidentate P-alkene ligands was observed in the presence of Lewis basic solvents, and model compounds of mono- and bis-solvated species (13, 14) were isolated. Cu formed trigonal-planar neutral (15-17) and cationic complexes (18, 19) of the general formulas [CuI(?¹P-alkene)₂] and [Cu(?¹P-alkene)₂BF₄], respectively (P-alkene = 2, 4, 5). The cationic Rh species 11 catalyzed the 1,4-addition of arylboronic acids to cyclic and linear enones with high activities (TON = 62 at 40 °C) and excellent enantiocontrol (up to 99% ee) for a wide range of substrates. The cationic Cu complex 18 catalyzed the 1,4-addition of Al(C₂H₅)₃ to 2-cyclohexenone with 39% ee.

A comparative study was performed between the trypanocidal efficacy of and associated immune response to benznidazole and posaconazole in a murine model of Chagas disease. Both drugs led to 100% survival, suppression of parasitaemia and reduction of specific anti-Trypanosoma cruzi antibodies following chronic infection. All posaconazole-treated animals had negative haemocultures at 54 days post infection, whilst 50% of those treated with benznidazole had positive results. Although both drugs were effective in reducing parasitism and inflammation in the heart, posaconazole-treated animals had plasma enzymatic levels of cardiac lesion that were indistinguishable from those of uninfected mice, whilst for benznidazole the enzyme levels were significantly higher than those of uninfected controls 31 days after the start of treatment. Posaconazole was more effective than benznidazole in controlling spleen enlargement and unspecific splenocyte proliferation in the early acute phase, but allowed higher levels of activation of CD4⁺ and CD8⁺ T-cells in the late acute phase when the adaptive immune response takes control of the infection. These results support the notion that posaconazole could be superior to benznidazole for the treatment of T. cruzi infection in humans.

The physical and chemical modification of cassava starch was carried out to prepare compounds that were evaluated as corrosion inhibitors of carbon steel under alkaline conditions in 200 mg L^-1 NaCl solutions. Two species were tested: an activated starch (AS) and a carboxymethylated starch (CMS) with two different degrees of substitution (DS). The success of the chemical procedure was confirmed by ¹³C NMR. The DS was determined by back titration and products with 0.13 (CMS_0.13) and 0.24 (CMS_0.24) were obtained. The inhibitive properties were studied by means of electrochemical impedance spectroscopy. It was found that modified starches have corrosion inhibitive properties and that their protection level depends on the type and amount of active groups present in the molecules. AS showed better performance than CMS, whose inhibition ability increases with the degree of substitution. This result was explained by the strong ionic interaction between AS and ferrous cations, which was confirmed by the electrostatic potential mapping of the monomeric units. After the corrosion experiments, the surfaces also were investigated through atomic force microscopy. It was found that a densification of the inhibitive layer was responsible for the higher protection level afforded by AS after 24 h of immersion.

The effect of directionality on the information propagation in a contagion model with complex propagation, i.e., that takes into account the need for simultaneous exposure to multiple activation sources, is studied. While it is known that complex propagation is blocked with increasing network randomness, here it is shown that network directionality affects such a result, leading to several different behaviors depending on the preservation of the in-degree or out-degree. The critical points for the occurrence of complex propagation in 1D directed small world networks are determined. It is shown that these points only depend on the number of outgoing links.

The levels of several chemical elements were determined simultaneously in ten different beers of the Venezuelan market by ICP-OES. With the exception of chromium, beer does not provide important amounts of nutritional oligoelements. The average chromium content found (33 µg/L) is higher than one reported for USA's beer (10 µg/L) but smaller than another reported for Brazilian beer (66 µg/L). The average percentage of chromium RDA by beer consumption found for Venezuela (6.3%) is similar to that reported for Belgium (5%). Regarding toxic elements, one of the samples contained an elevated amount of aluminium, probably dissolved from the aluminium can.

This study represents the first report on the distribution of KIR genes in 205 unrelated healthy mestizo Venezuelan individuals. Genotyping analysis showed that all KIR genes are present in this population. Frequency of inhibitory killer cell immunoglobulin-like receptors (KIRs) exceeded 0.69, except for KIR2DL2 (0.29) and 2DL5 (0.37). Activating KIRs showed low frequencies (0.11-0.29), except for KIR2DS4 (0.68). Forty-five different KIR genotypes were identified, with a predominance of three genotypes found in 50.7% of the population of which 25.9% were individuals homozygous for haplotype A. The frequencies of KIR genes reflect the ethnic admixture existing in the mestizo Venezuelan population.

Age, growth and mortality of the toadfish, Halobatrachus didactylus, were determined by examination of the whole sagittal otoliths of fish sampled in the Bay of Cádiz (southwestern Spain) from March 1999 to March 2000. A total of 844 specimens (425 males, 416 females, and 3 of indeterminate sex), ranging from 95 to 470 mm in total length were examined. Eighty-nine percent of the otoliths could be read allowing an age estimation. The opaque zone was formed between April and May coincident with the maximum reproductive peak, while the translucent zone formed mainly in summer-fall (June to December). Maximum ages for males and females were 12 and 10 years, respectively. The samples were dominated by 2- to 6-year-old specimens. Males matured at an age of approximately 2 years and females at 3 years. Fish total length and otolith radius were closely related (r2 Greater than 0.80). The von Bertalanffy growth curve was used to describe growth. The parameters were derived from back-calculated length-at-age. Significant differences in the growth parameters were found between sexes (in males L8 = 477.06 mm, K = 0.15 and t0 = -0.59; in females L8 = 363.69 mm, K = 0.20 and t0 = -0.75). Although the growth analysis revealed that this species is slow-growing, males reached larger sizes than females. Females appeared to experience higher natural mortality rates than males.

We analyze the evolution in thickness and radius of the film formed during the collision of two deformable emulsion Brownian droplets. These variables exhibit random fluctuations due to thermal disturbances from the continuous liquid phase. As a result, the system probes a random trajectory in the configurational space until it reaches a critical film thickness, at which point the droplets coalesce. Therefore, the film is modeled as a disk with thicknesses and radi that can fluctuate. Our analysis is based on a Langevin-Brownian dynamics approach, which accounts for the thermodynamic and hydrodynamic interactions in the lubrication approximation. We examine the effect of parameters such as droplet size, interfacial mobility, and electrolyte concentration on the coalescence of small Brownian droplets. The results suggest that the coalescence times depend on a complex interplay between the thermodynamic and hydrodynamic interactions.