Evaluation of the Phytochemicals and the Antibacterial Properties of Sida Acuta Leaf Extract and their Effects on Wound Bacterial Isolates

This study was performed to evaluate the phyto-chemical and antibacterial properties of Sida acuta leaf extract against wound bacterial isolates. Standard methods were employed in the phytochemistry, the bacterial identification and the antibiotic susceptibility assay. Ethanol and acetone were used as the extraction solvents. Results obtained from the phytochemical analyses of the ethanol the acetone extracts revealed the presence of alkaloids, saponins, tannins, steroids, glycosides, polyphenols, oxalate and flavonoids. The sensitivity of the isolates to the extracts was represented by zones of inhibition at different concentrations. The highest zones of inhibition was observed at 50 mg/ml while the lowest was observed at 3.125 mg/ml. Gram-positive bacteria were found to be more sensitive to the extracts at different concentrations than the Gram-negative bacteria (p > 0.05). The minimum inhibitory concentration of both extracts against the Gram-positive and Gram-negative bacterial isolates were: 3.125 mg/ml and 6.25 mg/ml respectively. The minimum bacteriocidal concentration of both extracts against Gram-positive and Gram-negative bacterial isolates were: 12.5 mg/ml and 25 mg/ml respectively. The antibiogram of the isolates against standard antibiotics used as positive control revealed the resistant pattern of the isolates to conventional antibiotics used in medicine. The potential antibacterial effect of Sida acuta leaf extract has been revealed in this study, therefore its controlled use should be encouraged in the treatment of wounds and other infections caused by the bacterial isolates.Keywords: Antimicrobial properties, Bacteria, Phytochemical analysis, Sida acuta, Wound

A 3D model for thickness and diffusion capacitance of emitter-base junction in a bifacial polycrystalline solar cell

Through this paper, we present n+-p-p+ solar cell. Mathematical relations describing the generated carriers’ density are expressed, using among others a new approach involving both junction and back surface recombination velocities in a 3D modelling study.Based on the normalized carriers’ density versus the base depth and operating an open circuit voltage, we study the space-charge layer thickness (Z) versus various parameters such as the grain size (g) and the grain boundaries recombination velocity (Sgb). Hence, the relationship between Z and the diffusion capacitance show that junction in the n+-p-p+ solar cell, when the columnar orientation is considered, is characterized by the plane capacitor properties

Elastic Wavefield Modeling for Arbitrarily Oriented Orthotropic Media

Composite materials have gained a considerable importance, being widely applied e.g. in aerospace industries as unidirectional, layered or woven structures. Through their complex build-up these materials exhibit anisotropic elastic behavior, raising considerable difficulties for ultrasonic nondestructive testing techniques. In modeling the interaction of elastic waves with such media a simple tool of assisting analysis is available. In this respect, simulation and optimization allow for a reduction of experimental work and an increase in reliability of applied testing procedures. For materials exhibiting orthotropic elastic symmetry, fundamental plane wave characteristics are presented in this contribution. These relationships are further applied for transducer-field modeling using the Generalized Point Source Synthesis method [1]. Since for complex-shaped components the material’s natural symmetry planes are in general not identical with the component’s surfaces, a respective transformation has been applied recently to yield a compact elastic tensor representation for such configurations [2]. Based on this formulation, all analytical results are obtained in a coordinate-free form, where the material’s spatial orientation appears as an additional parameter. Since orthotropy includes the higher symmetries tetragonal, transversely isotropic, cubic and isotropic, the results presented cover most of the materials of today’s industrial interest. Numerical results cover slowness and group velocity diagrams as well as field pattern calculations for commercial transducers including time-depedent rf-impulse modeling

Functionalized α-Helical Peptide Hydrogels for Neural Tissue Engineering.

This is the final version of the article. Available from the American Chemical Society via the DOI in this record.Trauma to the central and peripheral nervous systems often lead to serious morbidity. Current surgical methods for repairing or replacing such damage have limitations. Tissue engineering offers a potential alternative. Here we show that functionalized α-helical-peptide hydrogels can be used to induce attachment, migration, proliferation and differentiation of murine embryonic neural stem cells (NSCs). Specifically, compared with undecorated gels, those functionalized with Arg-Gly-Asp-Ser (RGDS) peptides increase the proliferative activity of NSCs; promote their directional migration; induce differentiation, with increased expression of microtubule-associated protein-2, and a low expression of glial fibrillary acidic protein; and lead to the formation of larger neurospheres. Electrophysiological measurements from NSCs grown in RGDS-decorated gels indicate developmental progress toward mature neuron-like behavior. Our data indicate that these functional peptide hydrogels may go some way toward overcoming the limitations of current approaches to nerve-tissue repair.This work was supported by the Biotechnology and Biological Sciences Research Council (H01716X, D.N.W. and M.A.B.); the European Research Council (StG243261, BS; and ADG340764, D.N.W.); the Royal Society (UF051616, B.S.); the Medical Research Council (G1100623, A.D.R.); and the Engineering and Physical Sciences Research Council (Bristol Chemical Synthesis Centre for Doctoral Training, EP/G036764/1, K.L.H.). D.N.W. holds a Royal Society Wolfson Research Merit Award

Insight into greenhouse gases emissions from the two popular treatment technologies in municipal wastewater treatment processes

© 2019 Elsevier B.V. Due to the impact of methane, carbon dioxide and nitrous oxide on global warming, the quantity of these greenhouse gases (GHG) emissions from municipal wastewater treatment plants (WWTPs) has attracted more and more attention. Consequently, GHG emissions from the two popular treatment technologies: anaerobic/anoxic/oxic (AAO) process and sequencing batch reactor (SBR) should be properly identified and discussed toward the current situation in developing countries. Direct and indirect carbon dioxide (with and/or without including in Intergovernmental Panel on Climate Change (IPCC) report) are all discussed in this article. This literature study observed that a quantity of total carbon dioxide emissions from SBR (374 g/m3 of wastewater) was double that of AAO whilst 10% of these was direct carbon dioxide. Methane emitted from an SBR was 0.50 g/m3 wastewater while 0.18 g CH4/m3 wastewater was released from an AAO. The level of nitrous oxide from AAO and SBR accounted for 0.97 g/m3 wastewater and 4.20 g/m3 wastewater, respectively. Although these results were collected from different WWTPs and where influent was in various states, GHGs emitted from both biological units and other treatment units in various processes are significant. The results also revealed that aerated zone is the major contributing factor in a wastewater treatment plant to the large amount of GHG emissions

T cell receptor sequence clustering and antigen specificity

There has been increasing interest in the role of T cells and their involvement in cancer, autoimmune and infectious diseases. However, the nature of T cell receptor (TCR) epitope recognition at a repertoire level is not yet fully understood. Due to technological advances a plethora of TCR sequences from a variety of disease and treatment settings has become readily available. Current efforts in TCR specificity analysis focus on identifying characteristics in immune repertoires which can explain or predict disease outcome or progression, or can be used to monitor the efficacy of disease therapy. In this context, clustering of TCRs by sequence to reflect biological similarity, and especially to reflect antigen specificity have become of paramount importance. We review the main TCR sequence clustering methods and the different similarity measures they use, and discuss their performance and possible improvement. We aim to provide guidance for non-specialists who wish to use TCR repertoire sequencing for disease tracking, patient stratification or therapy prediction, and to provide a starting point for those aiming to develop novel techniques for TCR annotation through clustering

Maximum levels of hepatitis C virus lipoviral particles are associated with early and persistent infection

Background & Aims: Hepatitis C virus (HCV) is bound to plasma lipoproteins and circulates as an infectious lipoviral particle (LVP). Experimental evidence indicates that LVPs have decreased susceptibility to antibody-mediated neutralisation and higher infectivity. This study tested the hypothesis that LVPs are required to establish persistent infection, and conversely, low levels of LVP in recent HCV infection increase the probability of spontaneous HCV clearance. Methods: LVP in non-fasting plasma was measured using the concentration of HCV RNA bound to large >100 nm sized lipoproteins after ex vivo addition of a lipid emulsion, that represented the maximum concentration of LVP (maxi-LVP). This method correlated with LVP in fasting plasma measured using iodixanol density gradient ultracentrifugation. Maxi-LVP was measured in a cohort of 180 HCV participants with recent HCV infection and detectable HCV RNA from the Australian Trial in Acute Hepatitis C (ATAHC) and Hepatitis C Incidence and Transmission Study in prison (HITS-p) cohorts. Results: Spontaneous clearance occurred in 15% (27 of 180) of individuals. In adjusted analyses, low plasma maxi-LVP level was independently associated with spontaneous HCV clearance (≤827 IU/ml; adjusted odds ratio 3.98, 95% CI: 1.02, 15.51, P = 0.047), after adjusting for interferon lambda-3 rs8099917 genotype, estimated duration of HCV infection and total HCV RNA level. Conclusions: Maxi-LVP is a biomarker for the maximum concentration of LVP in non-fasting samples. Low maxi-LVP level is an independent predictor of spontaneous clearance of acute HCV

Increasing the frequency of hand washing by healthcare workers does not lead to commensurate reductions in staphylococcal infection in a hospital ward

Hand hygiene is generally considered to be the most important measure that can be applied to prevent the spread of healthcare-associated infection (HAI). Continuous emphasis on this intervention has lead to the widespread opinion that HAI rates can be greatly reduced by increased hand hygiene compliance alone. However, this assumes that the effectiveness of hand hygiene is not constrained by other factors and that improved compliance in excess of a given level, in itself, will result in a commensurate reduction in the incidence of HAI. However, several researchers have found the law of diminishing returns to apply to hand hygiene, with the greatest benefits occurring in the first 20% or so of compliance, and others have demonstrated that poor cohorting of nursing staff profoundly influences the effectiveness of hand hygiene measures. Collectively, these findings raise intriguing questions about the extent to which increasing compliance alone can further reduce rates of HAI. In order to investigate these issues further, we constructed a deterministic Ross-Macdonald model and applied it to a hypothetical general medical ward. In this model the transmission of staphylococcal infection was assumed to occur after contact with the transiently colonized hands of HCWs, who, in turn, acquire contamination only by touching colonized patients. The aim of the study was to evaluate the impact of imperfect hand cleansing on the transmission of staphylococcal infection and to identify, whether there is a limit, above which further hand hygiene compliance is unlikely to be of benefit. The model demonstrated that if transmission is solely via the hands of HCWs, it should, under most circumstances, be possible to prevent outbreaks of staphylococcal infection from occurring at a hand cleansing frequencies <50%, even with imperfect hand hygiene. The analysis also indicated that the relationship between hand cleansing efficacy and frequency is not linear - as efficacy decreases, so the hand cleansing frequency required to ensure R0<1 increases disproportionately. Although our study confirmed hand hygiene to be an effective control measure, it demonstrated that the law of diminishing returns applies, with the greatest benefit derived from the first 20% or so of compliance. Indeed, our analysis suggests that there is little benefit to be accrued from very high levels of hand cleansing and that in most situations compliance >40% should be enough to prevent outbreaks of staphylococcal infection occurring, if transmission is solely via the hands of HCWs. Furthermore we identified a non-linear relationship between hand cleansing efficacy and frequency, suggesting that it is important to maximise the efficacy of the hand cleansing process