113 research outputs found

    Reduction of Some Enzymes Produced by Irradiated Fungal Strains Isolated from Certain Medicinal Plants

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    Medicinal plants normally carry high bioburden due to their origin, offering potentials hazards to the consumer. Fungal extracellular enzymes play a role in biodeterioration of medicinal plants and undesirably effect human health cause immunotoxigenic diseases. Ten different medicinal plants were screened for their mold contamination. The isolates were identified as genera Aspergillus, Alternaria, Cladosporium and Penicillum, they tested for their enzymatic activities (protease, cellulase and lipase). All isolates were able to produce enzymes under study in a varying degree. Of the fungal isolates , Asp. niger and Asp. flavus showed high protease activity. Whereas P. roquefortii and Asp. parasiticus were the more potent strains producing cellulase. Lipase was found to be highly produced by Asp. fumigatus and P. italicum . The present study presumes to monitor the fungal growth and enzymatic activity in relation to gamma irradiation. The results showed that, the log number of survivors was found to be inversely proportional to the irradiation dose. 6.0 and 4.0 kGy resulted in complete inhibition the growth of  highly protease produces (Asp. niger and Asp.flavus). While,  P. roquefortii and Asp. parasiticus which highly produce cellulase were inhibited at 4.0 and 6.0 kGy, respectively. On the other hand, Asp.fumigatus and P. italicum which highly produce lipase were inhibited at dose 4.0 and 6.0 kGy, respectively. Subleathal doses of gamma- irradiation resulted in high significant reduction of enzymes production. The stability of acquired character for the strains under study which were exposed to gamma-irradiation was studied. Statistical analysis revealed that, the enzyme activities estimated after 6 months of storage gave difference data between the strains under study. This study indicates that gamma irradiation is an effective treatment for reduction of fungi contaminating medicinal plants as well as its ability to produce some enzymes. Key words: medicinal plants, fungal isolates, enzymatic activity, gamma irradiation

    Probabilistic performance modelling when using partial reconfiguration to accelerate streaming applications with non-deterministic task scheduling

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    Many streaming applications composed of multiple tasks self-adapt their tasks’ execution at runtime as response to the processed data. This type of application promises a better solution to context switches at the cost of a non-deterministic task scheduling. Partial reconfiguration is a unique feature of FPGAs that not only offers a higher resource reuse but also performance improvements when properly applied. In this paper, a probabilistic approach is used to estimate the acceleration of streaming applications with unknown task schedule thanks to the application of partial reconfiguration. This novel approach provides insights in the feasible acceleration when partially reconfiguring regions of the FPGA are partially reconfigured in order to exploit the available resources by processing multiple tasks in parallel. Moreover, the impact of how different strategies or heuristics affect to the final performance is included in this analysis. As a result, not only an estimation of the achievable acceleration is obtained, but also a guide at the design stage when searching for the highest performance

    Interface modification of clay and graphene platelets reinforced epoxy nanocomposites: a comparative study

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    The interface between the matrix phase and dispersed phase of a composite plays a critical role in influencing its properties. However, the intricate mecha-nisms of interface are not fully understood, and polymer nanocomposites are no exception. This study compares the fabrication, morphology, and mechanical and thermal properties of epoxy nanocomposites tuned by clay layers (denoted as m-clay) and graphene platelets (denoted as m-GP). It was found that a chemical modification, layer expansion and dispersion of filler within the epoxy matrix resulted in an improved interface between the filler mate-rial and epoxy matrix. This was confirmed by Fourier transform infrared spectroscopy and transmission electron microscope. The enhanced interface led to improved mechanical properties (i.e. stiffness modulus, fracture toughness) and higher glass transition temperatures (Tg) compared with neat epoxy. At 4 wt% m-GP, the critical strain energy release rate G1c of neat epoxy improved by 240 % from 179.1 to 608.6 J/m2 and Tg increased from 93.7 to 106.4 �C. In contrast to m-clay, which at 4 wt%, only improved the G1c by 45 % and Tg by 7.1 %. The higher level of improvement offered by m-GP is attributed to the strong interaction of graphene sheets with epoxy because the covalent bonds between the carbon atoms of graphene sheets are much stronger than silicon-based clay

    Peptidomimetic and Non- Peptidomimetic Derivatives as Possible SARS-CoV-2 Main Protease (Mpro) Inhibitors

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    To design novel inhibitors of the SARS-CoV-2 main protease (Mpro), we investigated the binding mode of the recently reported α-ketoamide inhibitors of this enzyme. Following, we utilized in-silico screening to identify 168 peptidomimetic and non-peptidomimetic compounds that are high probability Mpro binding candidates. The compounds were synthesized in 5 to 10 mg for initial screening for their potential inhibition of Mpro using Fluorescence Resonance Energy Transfer (FRET) assay. The study was conducted using the main protease, MBP-tagged (SARS-CoV-2) Assay Kit (BPS Bioscience, #79955-2), and the fluorescence due to enzymatic cleavage of substrate measured using BMG LABTECH CLARIOstar™, a fluorescent microplate reader, with an excited/emission wavelength of 360 nm/460 nm, respectively. The FRET assay showed 29 compounds to exhibit lower fluorescence compared to the positive control, indicating inhibitory activity, with three of the compounds exhibiting over 50% enzymatic inhibition. The assay average scores were plotted as dose inhibition curves using variable parameter nonlinear regression to calculate the IC50 values. To design more potent inhibitors, an in-silico molecular docking simulation using the SARS-CoV-2 Mpro crystal structure was conducted to investigate on a molecular level the key binding residues at the active site, as well as the possible binding modes and affinity of the lead inhibitors. Additionally, an in-silico study of the compounds\u27 molecular properties and physicochemical profiles was performed to predict their pharmacokinetic properties and assess their suitability as potential orally active drug candidates.https://scholarscompass.vcu.edu/gradposters/1139/thumbnail.jp

    Genic SNP markers and legume synteny reveal candidate genes underlying QTL for Macrophomina phaseolina resistance and maturity in cowpea [Vigna unguiculata (L) Walp.]

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    <p>Abstract</p> <p>Background</p> <p><it>Macrophomina phaseolina </it>is an emerging and devastating fungal pathogen that causes significant losses in crop production under high temperatures and drought stress. An increasing number of disease incidence reports highlight the wide prevalence of the pathogen around the world and its contribution toward crop yield suppression. In cowpea [<it>Vigna unguiculata </it>(L) Walp.], limited sources of low-level host resistance have been identified, the genetic basis of which is unknown. In this study we report on the identification of strong sources of host resistance to <it>M. phaseolina </it>and the genetic mapping of putative resistance loci on a cowpea genetic map comprised of gene-derived single nucleotide polymorphisms (SNPs) and amplified fragment length polymorphisms (AFLPs).</p> <p>Results</p> <p>Nine quantitative trait loci (QTLs), accounting for between 6.1 and 40.0% of the phenotypic variance (R<sup>2</sup>), were identified using plant mortality data taken over three years in field experiments and disease severity scores taken from two greenhouse experiments. Based on annotated genic SNPs as well as synteny with soybean (<it>Glycine max</it>) and <it>Medicago truncatula</it>, candidate resistance genes were found within mapped QTL intervals. QTL <it>Mac-2 </it>explained the largest percent R<sup>2 </sup>and was identified in three field and one greenhouse experiments where the QTL peak co-located with a SNP marker derived from a pectin esterase inhibitor encoding gene. Maturity effects on the expression of resistance were indicated by the co-location of <it>Mac-6 </it>and <it>Mac-7 </it>QTLs with maturity-related senescence QTLs <it>Mat-2 </it>and <it>Mat-1</it>, respectively. Homologs of the <it>ELF4 </it>and <it>FLK </it>flowering genes were found in corresponding syntenic soybean regions. Only three <it>Macrophomina </it>resistance QTLs co-located with delayed drought-induced premature senescence QTLs previously mapped in the same population, suggesting that largely different genetic mechanisms mediate cowpea response to drought stress and <it>Macrophomina </it>infection.</p> <p>Conclusion</p> <p>Effective sources of host resistance were identified in this study. QTL mapping and synteny analysis identified genomic loci harboring resistance factors and revealed candidate genes with potential for further functional genomics analysis.</p

    Distributed Drug Discovery, Part 1: Linking Academia and Combinatorial Chemistry to Find Drug Leads for Developing World Diseases

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    A Low-Cost High Performance Electric Vehicle Design Based on Variable Structure Fuzzy PID Control

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    This paper introduces the design steps and implementation of Electric Vehicle (EV) based on variable structure fuzzy PID control. The role of fuzzy logic is making change in the membership function to tune the fuzzy action according to the error and change of error. The control implementation was executed using a low-cost Arduino mega 2560 and had been programed by MATLAB SIMULINK.  Also, a nonlinear model for the EV was built and validated by the actual performance of the EV experimental setup. The overall EV closed loop implemented on the MATLAB SIMULINK to select the proper control parameters. The proposed variable structure fuzzy PID control had been compared to the traditional PID control to ensure robustness and reliability. The results show that the proposed control technique can deal with the EV disturbances and continuous change in the operating points

    The Effects of the Oxytocin Hormone Induction on the Value of the Composition of Etawah Crossbred Goat Milk

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    This study aims to see the extent of influence of oxytocin hormone induction on the nutritional composition of milk in the Etawah Crossbred goat. This research was conducted in December 2018 in Syiah Kuala District, Banda Aceh, Indonesia. The examined parameters were the levels of fat, nonfat dry matter (BKTL), protein content, lactose content and milk density. The research used 18 Etawah goats and oxytocin hormone. A statistical unpaired t test indicated a highly significant influence (P 0.05) in milk, i.e. 8.39%, 3.91% and 3.76%, respectively. In conclusion, hormone oxytocin injection had a highly significant effect on increasing milk fat levels and significantly affected the decrease in milk density but did not affect the level of nonfat dry matter (BKTL), lactose and protein
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