Numerical analysis of flow in an elastic artery model.

Oscillatory and pulsatile flows of Newtonian fluids in straight elastic tubes are simulated numerically with the aid of Ling and Atabek's "local flow" assumption for the nonlinear convective acceleration terms. For the first time, a theoretical assessment of the local flow assumption is presented, and the range of validity of the assumption is estimated by comparison with perturbation solutions of the complete flow problem. Subsequent simulations with the local flow model indicate that the flow field and associated wall shear stress are extremely sensitive to the phase angle between oscillatory pressure and flow waves (impedance phase angle). This phase angle, which is a measure of the wave reflection present in the system, is known to be altered by arterial disease (e.g., hypertension) and vasoactive drugs. Thus, the paper elucidates a mechanism by which subtle changes in systemic hemodynamics (i.e., phase angles) can markedly influence local wall shear stress values.     

Antimalarial properties of imipramine and amitriptyline

Dietary riboflavin deficiency is known to diminish malarial parasitemia. In this study, we determined whether imipramine and amitriptyline, drugs which inhibit riboflavin metabolism, have antimalarial efficacy. In addition, we evaluated whether these drugs, like other antimalarial agents, increase the hemolytic response to ferriprotoporphyrin IX (FP). The growth of Plasmodium falciparum (FCR3) in the absence and presence of these drugs (10 to 75 microM) was measured by determining (3H)hypoxanthine uptake by intra-erythrocytic parasites for 48 h in RPMI 1640 medium. The uptake of (3H)hypoxanthine was significantly reduced in a dose-dependent manner by both imipramine and amitriptyline. The IC50 values of imipramine and amitriptyline at 48 h were 56 and 45 microM, respectively. Both drugs enhanced hemolysis induced by FP (10 or 20 microM). No hemolysis by these drugs was detected in the absence of FP. It is concluded that the tricyclic antidepressants, imipramine and amitriptyline, possess substantial antimalarial properties.     

Cointegration and nonlinear causality among ethanol‐related prices: evidence from Brazil

The objective of this study was to investigate the causal relationships among crude oil, ethanol and sugar prices in the context of Brazil. In doing so, we consider the application of ARDL bound tests to examine whether these variables comove in the long run. Besides, we employ a recently developed nonlinear symmetric and asymmetric test for noncausality which assists us to explore the short‐run ‘lead–lag’ associations among the price indexes under review. The results of the ARDL bound test indicate that cointegration exists only when the ethanol price is used as the dependent variable. This finding suggests that oil and sugar prices lead the Brazilian ethanol prices in the long run. Moreover, the results of nonlinear causality test also confirm the existence of a short‐term unidirectional causality running from sugar to ethanol market. We also document that the impact of sugar prices on ethanol prices appears to be positive indicating that rising sugar prices will cause a growth in the ethanol prices. Our findings further demonstrate that sugar prices are not affected by the fluctuations in ethanol price. The results carry important implications for policymakers.     

Coordination of different ligands to copper(II) and cobalt(III) metal centers enhances Zika virus and dengue virus loads in both arthropod cells and human keratinocytes

Trace elements such as copper and cobalt have been associated with virus-host interactions. However, studies to show the effect of conjugation of copper(II) or cobalt(III) metal centers to thiosemicarbazone ligand(s) derived from either food additives or mosquito repellent such as 2-acetylethiazole or citral, respectively, on Zika virus (ZIKV) or dengue virus (serotype 2; DENV2) infections have not been explored. In this study, we show that four compounds comprising of thiosemicarbazone ligand derived from 2-acetylethiazole viz., (E)-N-ethyl-2-[1-(thiazol-2-yl)ethylidene]hydrazinecarbothioamide (acetylethTSC) (compound 1), a copper(II) complex with acetylethTSC as a ligand (compound 2), a thiosemicarbazone ligand-derived from citral (compound 3) and a cobalt(III) complex with a citral-thiosemicarbazone ligand (compound 4) increased DENV2 and ZIKV replication in both mosquito C6/36 cells and human keratinocytes (HaCaT cells). Treatment of both cell lines with compounds 2 or 4 showed increased dengue viral titers at all three tested doses. Enhanced dengue viral plaque formation was also noted at the tested dose of 100 μM, suggesting higher production of infectious viral particles. Treatment with the compounds 2 or 4 enhanced ZIKV and DENV2 RNA levels in HeLa cell line and primary cultures of mouse bone marrow derived dendritic cells. Also, pre- or post treatments with conjugated compounds 2 or 4 showed higher loads of ZIKV or DENV2 envelope (E) protein in HaCaT cells. No changes in loads of E-protein were found in ZIKV-infected C6/36 cells, when compounds were treated after infection. In addition, we tested bis(1,10-phenanthroline)copper(II) chloride ([Cu(phen)₂]Cl₂, (compound 5) and tris(1,10-phenanthroline)cobalt(III) chloride ([Co(phen)₃]Cl₃, (compound 6) that also showed enhanced DENV2 loads. Also, we found that copper(II) chloride dehydrate (CuCl₂·2H₂O) or cobalt(II) chloride hexahydrate (CoCl₂·6H₂O) alone had no effects as “free” cations. Taken together, these findings suggest that use of Cu(II) or Co(III) conjugation to organic compounds, in insect repellents and/or food additives could enhance DENV2/ZIKV loads in human cells and perhaps induce pathogenesis in infected individuals or individuals pre-exposed to such conjugated complexes.

In silico studies on bacterial xylanase enzyme: Structural and functional insight

Xylans are the second most abundant form of hemicelluloses and are the second most abundant polysaccharide in nature after cellulose. To degrade xylan, microbes produce mainly xylanase enzyme. Wide range of microorganisms like fungi, bacteria, yeast, marine algae etc. are capable of producing xylanase. Main source of xylanase is fungi but industrial production of bacterial xylanase is low cost, easy downstream process and high production rate. To understand primary, secondary and tertiary structure of xylanase, in silico composition of amino acids, basic physiological characteristics; viz., pI, molecular weight, instability index, GRAVY, molar extinction coefficient, secondary structure, presence of functional domain and motifs, phylogenetic tree, salt bridge compositions are determined. In silico study of xylanase focused on 36 different bacterial sources are performed by retrieving FASTA and PDB sequences using RCSB PDB. FASTA and PDB files are proceed further in ExPASy-ProtParam, RAMPAGE, QMEAN, MEME, PSIPRED, InterProScan, MOTIF scan, ERRAT, Peptide cutter, ESBRI and MEGA 7. The instability index range (16.90–38.78) clearly indicates that the protein is highly stable. α-helix mean value (27.11%) infers the protein is dominated by α-helix region. The aliphatic index (39.80–90.68) gives information that the protein is highly thermostable, prevalence by alanine amino acid in aliphatic side chain. No transmembrane domain was found in the protein which confirms the enzyme is extracellular in nature. Ancestor chart analysis confirmed that it is a part of carbohydrate metabolic process and more specifically a member of glycoside hydrolase super family.     

On the infiltration of Golgi bodies from the follicular epithelium to the egg

Summary 1. In a well advanced oocyte of the tortoise the egg membranes besides the theca and the single-layered epithelium consist of a zona pellucida often differentiated into zona striata and a homogeneous layer; underlying these two layers is a layer of cortical fibrillae or fibrillar layer, Next to this layer, is the limiting membrane of the egg which is not present in all stages and generally disappears in a well developed oocyte. In certain animals either the homogeneous layer or fibrillar layer is absent. 2. In certain animals,Golgi bodies seem to be extruded into the follicle cells from the theca cells. 3. At a particular stage of development the follicle cells become very active and produce a large number of smallGolgi bodies. TheseGolgi granules filter through canalicular passages of the zona radiata into either the homogeneous layer and from thence into the fibrillar layer or where a homogeneous layer is not present directly to the fibrillar layer. Where a fibrillar layer is not present they are transferred directly to the limiting membrane and from thence to the egg. 4. In certain cases e. g. in Fowl, Calotes and Uromastix, fairly large lumps ofGolgi bodies are extruded from the follicle cells through the zona pellucida into the egg. Here the fine canilicular passages do not seem to form a vehicle for the passage of these comparatively larger bodies. 5. The fine canalicular passages in the zona radiata ofTestudo graeca andKachuga smithii and the fibrillar prolongation of the cytoplasm which we have called the fibrillar layer are marked features of the egg membranes at certain stages of development of the egg. During the period when infiltration ofGolgi bodies through these passages takes place slides prepared by silver nitrate and osmic methods show black beaded chains ofGolgi granules in various stages of descent. 6. It is claimed that the extrusion and infiltration ofGolgi bodies from the follicular epithelium to the egg are established phenomena at least in the Vertebrates.     

Sterols and fatty acids from three species of mangrove

The hydrolysis of steryl esters on thin-layer chromatographic plates by porcine pancreatic lipase is described. The sterols and fatty acids produced were separated on the same plate, recovered, and analysed by gas-liquid chromatography for their compositions. Synthetic cholesteryl esters containing various saturated and unsaturated fatty acids and synthetic steryl oleates with various sterols were lipolysed along with steryl esters of Acanthus ilicifolius, Bruguiera gymnorhiza and Rhizophora mucronata mangrove leaves. The major sterol was sitosterol which was accompanied by cholesterol, campesterol, stigmasterol and 28-isofucosterol. In addition, stigmast-7-en-3β-ol was present in R. mucronata leaves. The component fatty acids found in all three species were 16:0, 18:0, 18:1, 18:2 and 18:3. The relative proportions of the sterols and fatty acids were significantly different from the chemotaxonomic standpoint. The results obtained by carrying out plate lipolysis for 45 min at 40° compared well with those produced by conventional chemical hydrolysis.     

Water quality and soil properties of ponds as influenced by Makhana (Euryale ferox) cultivation

Summary Analysis of regularly collected samples of soil and water from Makhana (Euryale ferox) growing ponds indicated that pH of soil and water were established near neutrality and C/N of soil near ten. Bicarbonate dominated soil extract while chloride dominated standing water. During grand growth period (March to June), Ca²⁺+Mg²⁺, NH ₄ ⁺ K⁺ increased while Na⁺ increased during decay of the plant (July to September) both in soil and plants. The soil had high contents of micro-nutrients, K and P. S.A.R. of soil was 3 to 4 times that of water. Free energy of exchange indicated stability and spontaneity.