29,226 research outputs found

    Reduction of leukocyte microvascular adherence and preservation of blood-brain barrier function by superoxide-lowering therapies in a piglet model of neonatal asphyxia

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    Background: Asphyxia is the most common cause of brain damage in newborns. Substantial evidence indicates that leukocyte recruitment in the cerebral vasculature during asphyxia contributes to this damage. We tested the hypothesis that superoxide radical (O2â‹…_) promotes an acute post-asphyxial inflammatory response and blood-brain barrier (BBB) breakdown. We investigated the effects of removing O2â‹…_ by superoxide dismutase (SOD) or C3, the cell-permeable SOD mimetic, in protecting against asphyxia-related leukocyte recruitment. We also tested the hypothesis that xanthine oxidase activity is one source of this radical.Methods: Anesthetized piglets were tracheostomized, ventilated, and equipped with closed cranial windows for the assessment of post-asphyxial rhodamine 6G-labeled leukocyte-endothelial adherence and microvascular permeability to sodium fluorescein in cortical venules. Asphyxia was induced by discontinuing ventilation. SOD and C3 were administered by cortical superfusion. The xanthine oxidase inhibitor oxypurinol was administered intravenously.Results: Leukocyte-venular adherence significantly increased during the initial 2 h of post-asphyxial reperfusion. BBB permeability was also elevated relative to non-asphyxial controls. Inhibition of O2â‹…_ production by oxypurinol, or elimination of O2â‹…_ by SOD or C3, significantly reduced rhodamine 6G-labeled leukocyte-endothelial adherence and improved BBB integrity, as measured by sodium fluorescein leak from cerebral microvessels.Conclusion: Using three different strategies to either prevent formation or enhance elimination of O2â‹…_ during the post-asphyxial period, we saw both reduced leukocyte adherence and preserved BBB function with treatment. These findings suggest that agents which lower O2â‹…_ in brain may be attractive new therapeutic interventions for the protection of the neonatal brain following asphyxia

    Redox supercapacitor performance of nanocrystalline molybdenum nitrides obtained by ammonolysis of chloride- and amide-derived precursors

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    Reactions of MoCl5 or Mo(NMe2)4 with ammonia result in cubic ?-Mo2N or hexagonal ?1-MoN depending on reaction time and temperature. At moderate temperatures the cubic product from Mo(NMe2)4 exhibits lattice distortions. Fairly high surface areas are observed in the porous particles of the chloride-derived materials and high capacitances of up to 275 F g?1 are observed when electrodes made from them are cycled in aqueous H2SO4 or K2SO4 electrolytes. The cyclic voltammograms suggest charge is largely stored in the electrochemical double layer at the surface of these materials. Amide-derived molybdenum nitrides have relatively low surface areas and smaller capacitances, but do exhibit strong redox features in their cyclic voltammograms, suggesting that redox capacitance is responsible for a significant proportion of the charge stored

    Balancing Local Order and Long-Ranged Interactions in the Molecular Theory of Liquid Water

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    A molecular theory of liquid water is identified and studied on the basis of computer simulation of the TIP3P model of liquid water. This theory would be exact for models of liquid water in which the intermolecular interactions vanish outside a finite spatial range, and therefore provides a precise analysis tool for investigating the effects of longer-ranged intermolecular interactions. We show how local order can be introduced through quasi-chemical theory. Long-ranged interactions are characterized generally by a conditional distribution of binding energies, and this formulation is interpreted as a regularization of the primitive statistical thermodynamic problem. These binding-energy distributions for liquid water are observed to be unimodal. The gaussian approximation proposed is remarkably successful in predicting the Gibbs free energy and the molar entropy of liquid water, as judged by comparison with numerically exact results. The remaining discrepancies are subtle quantitative problems that do have significant consequences for the thermodynamic properties that distinguish water from many other liquids. The basic subtlety of liquid water is found then in the competition of several effects which must be quantitatively balanced for realistic results.Comment: 8 pages, 6 figure

    Phylogenomic and comparative genomic studies robustly demarcate two distinct clades of Pseudomonas aeruginosa strains: proposal to transfer the strains from an outlier clade to a novel species Pseudomonas paraeruginosa sp. nov

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    The strains of Pseudomonas aeruginosa exhibit considerable differences in their genotypic and pathogenic properties. To clarify their evolutionary/taxonomic relationships, comprehensive phylogenomic and comparative genomic studies were conducted on the genome sequences of 212 P. aeruginosa strains covering their genetic diversity. In a phylogenomic tree based on 118 conserved proteins, the analysed strains formed two distinct clades. One of these clades, Clade- 1, encompassing >70 % of the strains including the type strain DSM 50071T, represents the species P. aeruginosa sensu stricto. Clade- 2, referred to in earlier work as the outlier group, with NCTC 13628T as its type strain, constitutes a novel species level lineage. The average nucleotide identity, average amino acid identity and digital DNA–DNA hybridization values between the strains from Clade- 1 and Clade- 2 are in the range of 93.4–93.7, 95.1–95.3 and 52–53 %, respectively. The 16S rRNA gene of P. aeruginosa DSM 50071T also shows 98.3 % similarity to that of NCTC13628T. These values are lower than the suggested cut- off values for species distinction, indicating that the Clade- 2 strains (NCTC 13628T) constitute a new species. We also report the identification of 12 conserved signature indels in different proteins and 24 conserved signature proteins that are exclusively found in either Clade- 1 or Clade- 2, providing a reliable means for distinguishing these clades. Additionally, in contrast to swimming motility, twitching motility is only present in Clade- 1 strains. Based on earlier work, the strains from these two clades also differ in their pathogenic mechanisms (presence/absence of Type III secretion system), production of biosurfactants, phenazines and siderophores, and several other genomic characteristics. Based on the evidence from different studies, we propose that the Clade- 2 strains constitute a novel species for which the name Pseudomonas paraeruginosa is proposed. The type strain is NCTC 13628T (=PA7T=ATCC 9027T). The description of Pseudomonas aeruginosa is also emended to include information for different molecular markers specific for this species

    Design of Subsurface Geodrain for Automated Industrial Unit – Case Study

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    This paper describes the pre-construction modeling for design and post-construction evaluation of subsurface drainage systems for an industrial plant. Rajshree Polyfil Ltd has a polyester filament manufacturing plant spread over 50 hectare area in Bharuch district of Gujarat State, India. The plant is fully automatic and robotics operated. The cable duct for control system was laid below formation level. The seepage water was observed in the cable trench and nearby vicinity. This seriously affects the functioning of computer controlled production system. Preliminary investigation revealed that the ground water level was around 1.0m depth below formation level, which was more than 15m depth during the construction of unit. Detailed subsurface investigations and field permeability tests are carried out. Subsurface drainage system was designed and its performance was estimated prior to construction of drain with the help of computer modeling using software MODFLOW. The model area was divided in three to five layers having different permeability values obtained from field test. After construction of subsurface geodrain, discharge was measured and water level was also measured at few piezometers installed near the drain. It is found that the performance of the drain is well in accordance with the design

    Microscopic derivation of multi-channel Hubbard models for ultracold nonreactive molecules in an optical lattice

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    Recent experimental advances in the cooling and manipulation of bialkali dimer molecules have enabled the production of gases of ultracold molecules that are not chemically reactive. It has been presumed in the literature that in the absence of an electric field the low-energy scattering of such nonreactive molecules (NRMs) will be similar to atoms, in which a single ss-wave scattering length governs the collisional physics. However, in Ref. [1], it was argued that the short-range collisional physics of NRMs is much more complex than for atoms, and that this leads to a many-body description in terms of a multi-channel Hubbard model. In this work, we show that this multi-channel Hubbard model description of NRMs in an optical lattice is robust against the approximations employed in Ref. [1] to estimate its parameters. We do so via an exact, albeit formal, derivation of a multi-channel resonance model for two NRMs from an ab initio description of the molecules in terms of their constituent atoms. We discuss the regularization of this two-body multi-channel resonance model in the presence of a harmonic trap, and how its solutions form the basis for the many-body model of Ref. [1]. We also generalize the derivation of the effective lattice model to include multiple internal states (e.g., rotational or hyperfine). We end with an outlook to future research.Comment: 19 pages, 4 figure

    Automatic classification of eutrophication of inland lakes from spacecraft data

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    The author has identified the following significant results. Spacecraft data and computer techniques can be used to rapidly map and store onto digital tapes watershed land use information. Software is now available by which this land use information can be rapidly and economically extracted from the tapes and related to coliform counts and other lake contaminants (e.g. phosphorus). These tools are basic elements for determining those land use factors and sources of nutrients that accelerate eutrophication in lakes and reservoirs
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