Secondary water pore formation for proton transport in a ClC exchanger revealed by an atomistic molecular dynamics simulation

Several prokaryotic ClC proteins have been demonstrated to function as exchangers that transport both chloride ions and protons simultaneously in opposite directions. However, the path of the proton through the ClC exchanger and how the protein brings about the coupled movement of both ions are still unknown. In the present work, we demonstrate that a previously unknown secondary water pore is formed inside a ClC exchanger by using an atomistic molecular dynamics (MD) simulation. From the systematic simulations, it was determined that the glutamate residue exposed to the intracellular solution, E203, plays an important role as a trigger for the formation of the secondary water pore. Based on our simulation results, we conclude that protons in the ClC exchanger are conducted via a water network through the secondary water pore and we propose a new mechanism for the coupled transport of chloride ions and protons

A monolithic and flexible fluoropolymer film microreactor for organic synthesis applications

A photocurable and viscous fluoropolymer with chemical stability is a highly desirable material for fabrication of microchemical devices. Lack of a reliable fabrication method, however, limits actual applications for organic reactions. Herein, we report fabrication of a monolithic and flexible fluoropolymer film microreactor and its use as a new microfluidic platform. The fabrication involves facile soft lithography techniques that enable partial curing of thin laminates, which can be readily bonded by conformal contact without any external forces. We demonstrate fabrication of various functional channels (similar to 300 mu m thick) such as those embedded with either a herringbone micromixer pattern or a droplet generator. Organic reactions under strongly acidic and basic conditions can be carried out in this film microreactor even at elevated temperature with excellent reproducibility. In particular, the transparent film microreactor with good deformability could be wrapped around a light-emitting lamp for close contact with the light source for efficient photochemical reactions with visible light, which demonstrates easy integration with optical components for functional miniaturized systems.open1112Ysciescopu

Effect of drying methods on the rheological characteristics and colour of yam flours

The effect of drying methods (sun and oven-drying) on the rheological properties and colour of amala, a thick paste from yam flour, was investigated using two varieties of yam (Dioscorea rotundata andDioscorea alata). The yam flour produced was later reconstituted to produce amala of different pasting characteristics, textural qualities and colour. D. rotundata produced amala of higher paste viscosities,and firmer gels were produced from D. rotundata than yam flour paste produced from D. alata. A higher water binding capacity (156.7%) was observed in yam flour paste produced from D. alata as comparedwith that of D. rotundata, while no significant difference was observed in the solubility index and swelling power of the two varieties. Blanching, a unit operation in yam flour processing, has a significant effect on the pasting characteristics of the reconstituted flour. It reduces the peak viscosity, holding strength, final viscosity, set back and elasticity but it has little or no significant effect on the adhesiveness, smoothness and cohesiveness of the paste. Sun and oven drying had no effect on thepasting characteristics or physicochemical properties. However, yam flour produced using sun drying method had a more elastic paste and a higher brown-index

Solvent extraction of molybdenum (VI) from diluted and concentrated hydrochloric acid

The solvent extraction of Mo (VI) from diluted and concentrated HCl solutions with tri-n-butyl phosphate (TBP) has been studied. The percentage Mo (VI) extraction (E%) reaches maximal levels of 49.60% and 51.20% at pH 1.0 and 4.0 respectively, however, it is much higher (E% = 85.60 –90.80%) in concentrated HCl (2.0 – 7.0M) solutions and decreases with temperature. The mechanism of extraction appears to be through the formation of condensed molybdic acid n(MoO3.2H2O). mTBP at low pH but involves molybdenyl species MoO2Cl2. (H2O) 2. mTBP in concentrated acid medium and pH 4-6. Electronic and infrared spectra data have been used to deduce the nature of the extracted species. Keywords: Molybdenum (VI), extraction, TBP, molybdic acid.Global Journal of Pure and Applied Sciences Vol. 14 (3) 2008: pp. 289-29

Stroke: Critical appraissal of intensive care management

Background: Stroke is a common medical condition in the medical units.Stroke patients are usually managed on the medical wards while some that needs organ support are admitted into the intensive care unit.However there is conflicting data on the benefits or otherwise of admitting stroke patients into the intensive care unit.This necessitated this study to know how much benefit is derived from admitting stroke patients into the intensive care unit.Aim and Objective: The study aims at the benefits of admitting stroke patients into the intensive care unit.The objective included studying the prognostic factors that determines the outcome of stroke patients admitted into the intensive care unit.Methodology: The case files of all patients admitted and managed in the intensive care unit of LAUTECH teaching hospital between 2002 and 2014 were retrieved and were analysed.The factors used in analyzing included the type of stroke,the age of the patients,the Glasgow Coma scale at admission,the need for intubation and mechanical ventilation as well as the percentage mortality in each subsets.Results: A total of 48 patients were admitted over the study period of which 19 were males and 29 were females.The percentage mortality in females was 78.95 while mortality in males was 62.5%.The higher the age the worse the prognosis, the higher the GCS the better the prognosis. Patients that were intubated and ventilated had percentage mortality of 68.8%.and better than non ventilated patients.The hemorrhagic strokes also carries worse prognosis.Conclusion: The admission of stroke patients to the intensive care unit should be individualized considering the above mentioned prognostic factors.However patients that are likely to benefit from intensive care unit should be admitted early for them to derive the maximum benefits.Keywords:Stroke,Intensive care unit,prognosis,benefit

SSumM: Sparse Summarization of Massive Graphs

Given a graph G and the desired size k in bits, how can we summarize G within k bits, while minimizing the information loss? Large-scale graphs have become omnipresent, posing considerable computational challenges. Analyzing such large graphs can be fast and easy if they are compressed sufficiently to fit in main memory or even cache. Graph summarization, which yields a coarse-grained summary graph with merged nodes, stands out with several advantages among graph compression techniques. Thus, a number of algorithms have been developed for obtaining a concise summary graph with little information loss or equivalently small reconstruction error. However, the existing methods focus solely on reducing the number of nodes, and they often yield dense summary graphs, failing to achieve better compression rates. Moreover, due to their limited scalability, they can be applied only to moderate-size graphs. In this work, we propose SSumM, a scalable and effective graph-summarization algorithm that yields a sparse summary graph. SSumM not only merges nodes together but also sparsifies the summary graph, and the two strategies are carefully balanced based on the minimum description length principle. Compared with state-of-the-art competitors, SSumM is (a) Concise: yields up to 11.2X smaller summary graphs with similar reconstruction error, (b) Accurate: achieves up to 4.2X smaller reconstruction error with similarly concise outputs, and (c) Scalable: summarizes 26X larger graphs while exhibiting linear scalability. We validate these advantages through extensive experiments on 10 real-world graphs.Comment: to be published in the 26th ACM SIGKDD International Conference on Knowledge Discovery and Data Mining (KDD '20

Selective prediction of interaction sites in protein structures with THEMATICS

<p>Abstract</p> <p>Background</p> <p>Methods are now available for the prediction of interaction sites in protein 3D structures. While many of these methods report high success rates for site prediction, often these predictions are not very selective and have low precision. Precision in site prediction is addressed using Theoretical Microscopic Titration Curves (THEMATICS), a simple computational method for the identification of active sites in enzymes. Recall and precision are measured and compared with other methods for the prediction of catalytic sites.</p> <p>Results</p> <p>Using a test set of 169 enzymes from the original Catalytic Residue Dataset (CatRes) it is shown that THEMATICS can deliver precise, localised site predictions. Furthermore, adjustment of the cut-off criteria can improve the recall rates for catalytic residues with only a small sacrifice in precision. Recall rates for CatRes/CSA annotated catalytic residues are 41.1%, 50.4%, and 54.2% for Z score cut-off values of 1.00, 0.99, and 0.98, respectively. The corresponding precision rates are 19.4%, 17.9%, and 16.4%. The success rate for catalytic sites is higher, with correct or partially correct predictions for 77.5%, 85.8%, and 88.2% of the enzymes in the test set, corresponding to the same respective Z score cut-offs, if only the CatRes annotations are used as the reference set. Incorporation of additional literature annotations into the reference set gives total success rates of 89.9%, 92.9%, and 94.1%, again for corresponding cut-off values of 1.00, 0.99, and 0.98. False positive rates for a 75-protein test set are 1.95%, 2.60%, and 3.12% for Z score cut-offs of 1.00, 0.99, and 0.98, respectively.</p> <p>Conclusion</p> <p>With a preferred cut-off value of 0.99, THEMATICS achieves a high success rate of interaction site prediction, about 86% correct or partially correct using CatRes/CSA annotations only and about 93% with an expanded reference set. Success rates for catalytic residue prediction are similar to those of other structure-based methods, but with substantially better precision and lower false positive rates. THEMATICS performs well across the spectrum of E.C. classes. The method requires only the structure of the query protein as input. THEMATICS predictions may be obtained via the web from structures in PDB format at: <url>http://pfweb.chem.neu.edu/thematics/submit.html</url></p