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Influence of alkaline treatment and fiber loading on the physical and mechanical properties of kenaf/polypropylene composites for variety of applications

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Progress in Natural Science:Materials International 2016年第6期26卷 657-664页

作者： Majid Niaz Akhtar abu bakar Sulong M.K.Fadzly Radzi N.F.Ismail M.R.Raza Norhamidi Muhamad Muhammad Azhar Khan Department of Physics COMSATS Institute of Information Technology Department of Mechanical and Materials Engineering Faculty of Engineering and Built EnvironmentUniversiti Kebangsaan Malaysia Department of Basic Sciences and Humanities Muhammad Nawaz Sharief University of Engineering and Technology(MNSUET) Department of Mechanical Engineering COMSATS Institute of Information Technology Department of Physics The Islamia University of Bahawalpur

Due to current trend and increasing interest towards natural based fiber products, Kenaf(Hibiscus cannabinus)fibers have been used for the developments of many products. Therefore, Kenaf fiber-reinforced composites have been widely used in engineering and industrial applications. The present work deals with the fabricating and characterization of untreated and treated kenaf/polypropylene(PP)-reinforced composites. Composites of PP reinforced with treated and untreated kenaf fibers were fabricated using the injection molding *** fiber loadings of 10, 20, 30, 40, 50 wt% treated and untreated kenaf composites were also prepared. Xray diffraction(XRD), scanning electron microscopy(SEM), Fourier transform infrared(FTIR) spectroscopy and thermo gravimetric analysis(TGA) were performed on the treated, untreated kenaf fibers and kenaf/PP composites. Moreover, the alkaline-treated kenaf composites exhibit better physical, morphological, and mechanical properties because of the compatibility of kenaf with PP. However, variations in tensile and flexural properties depend on treatment and kenaf fiber contents. The percentage increase in the mechanical properties of the treated kenaf/PP composites relative to that of PP was also measured. In addition, 40 wt%kenaf fiber loading resulted in higher mechanical properties. By contrast, kenaf/PP composite with 50% fiber loading was not successfully prepared because of improper mixing and the burning of kenaf fibers in the PP matrix. To conclude, 40% kenaf/PP composites with superior physical and mechanical properties may be used in variety of applications such as automotive, sports, construction, animal bedding, and mass production industries.

关键词： Kenaf composites Microstructures Physical properties Mechanical Testing Injection-molding

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mRNA transcriptome profiling of human hepatocellular carcinoma cells HepG2 treated with Catharanthus roseus-silver nanoparticles

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World Journal of Hepatology 2023年第3期15卷 393-409页

作者： Nur Asna Azhar Siti Aishah abu bakar Marimuthu Citartan Nor Hazwani Ahmad Department of Biomedical Science Advanced Medical and Dental InstituteUniversiti Sains MalaysiaKepala Batas 13200Pulau PinangMalaysia Liver Malignancies Research Program Advanced Medical and Dental InstituteUniversiti Sains MalaysiaKepala Batas 13200Pulau PinangMalaysia Faculty of Bioresources and Food Industry Universiti Sultan Zainal AbidinBesut CampusBesut 22200TerengganuMalaysia

BACKGROUND The demand for the development of cancer nanomedicine has increased due to its great therapeutic value that can overcome the limitations of conventional cancer ***,the presence of various bioactive compounds in crude plant extracts used for the synthesis of silver nanoparticles(AgNPs)makes its precise mechanisms of action *** To assessed the mRNA transcriptome profiling of human HepG2 cells exposed to Catharanthus roseus ***(***)-*** The proliferative activity of hepatocellular carcinoma(HepG2)and normal human liver(THLE3)cells treated with *** were measured using MTT *** RNA samples were extracted and sequenced using BGIseq500 *** is followed by data filtering,mapping,gene expression analysis,differentially expression genes analysis,Gene Ontology analysis,and pathway *** The mean IC 50 values of *** on HepG2 was 4.38±1.59μg/mL while on THLE3 cells was 800±1.55μg/*** profiling revealed an alteration of 296 *** induced the expression of stress-associated genes such as MT,HSP and *** signalling pathways were potentially activated through MAPK,TNF and TGF pathways that are responsible for apoptosis and cell cycle *** alteration of ARF6,EHD2,FGFR3,RhoA,EEA1,VPS28,VPS25,and TSG101 indicated the uptake of ***-AgNPs via both clathrin-dependent and clathrinindependent *** This study provides new insights into gene expression study of biosynthesised AgNPs on cancer *** cytotoxicity effect is mediated by the aberrant gene alteration,and more interestingly the unique selective antiproliferative properties indicate the *** as an ideal anticancer candidate.

关键词： Catharanthus roseus HepG2 Silver nanoparticles Transcriptome oxidative stress Apoptosis Cell cycle

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Effect of plant nutrition on aphid size, prey consumption, and life history characteristics of green lacewing

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Insect Science 2014年第1期21卷 74-82页

作者： Muhammad A. Aqueel Catherine M. Collins abu-bakar M. Raza Shahbaz Ahmad Muhammad Tariq Simon R. Leather Division of Ecology & Evolution Imperial College London Silwood Park Campus Ascot SL5 7PY United Kingdom Department of Entomology University College of Agriculture University of Sargodha Institute of Agricultural Sciences University of the Punjab Punjab Department of Entomology PMAS-Arid Agriculture University Rawalpindi Rawalpindi Pakistan

Plant quality can directly and indirectly affect the third trophic level. The predation by all the instars of green lacewing, Chrysoperla carnea （S.）（Neuroptera： Chrysopidae） on the cereal aphids, Rhopalosiphum padi （L.）, and Sitobion avenae （F.） at varying nitrogen fertilizer levels was calculated under laboratory conditions. Wheat plants were grown on four nitrogen fertilizer levels and aphids were fed on these plants and subsequently offered as food to the C. carnea. Aphid densities of 10, 30, and 90 were offered to first, second, and third instar larvae of green lacewing. Increased nitrogen application improved nitrogen contents of the plants and also the body weight of cereal aphids feeding on them. Aphid consumption by green lacewings was reduced with the increase in nitrogen content in the host plants of aphids. Predation of both aphid species by first, second, and third instars larvae of C. carnea was highest on aphids reared on plants with the lowest rate of fertilization, suggesting a compensatory consumption to overcome reduced biomass （lower aphid size）. Total biomass devoured by C. carnea on all nitrogen fertilizer treatments was not statistically different. Additionally, the heavier host prey influenced by the plant nutrition had an effect on the life history characteristics of green lacewings. The larval duration, pupal weight, pupal duration, fecundity, and male and female longevity were significantly affected by the level of nitrogen fertilization to the aphid＇s host plants, except for pupal duration when fed on S. avenae. This study showed that quantity of prey supplied to the larvae affects the prey consumption and thereafter the life history characteristics of green lacewings.

关键词： Chrysoperla carnea host plant nutrition tritrophic interactions

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A Mesh-Independent Brute-Force Approach for Traction-Free Corrections in Dislocation Problems

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Modeling and Numerical Simulation of Material Science 2021年第1期11卷 1-18页

作者： abu bakar Siddique Tariq Khraishi Mechanical Engineering Department University of New Mexico New Mexico USA

Simulation of dislocation dynamics opens the opportunity for researchers and scientists to observe in-depth many plastic deformation phenomena. In 2D or 3D media, modeling of physical boundary conditions accurately is one of the keys to the success of dislocation dynamics (DD) simulations. The scope of analytical solutions is restricted and applies to specific configurations only. But in dynamics simulations, the dislocations’ shape and orientation change over time thus limiting the use of analytical solutions. The authors of this article present a mesh-based generalized numerical approach based on the collocation point method. The method is applicable to any number of dislocations of any shape/orientation and to different computational domain shapes. Several verifications of the method are provided and successful implementation of the method in 3D DD simulations have been incorporated. Also, the effect of free surfaces on the Peach-Koehler force has been computed. Lastly, the effect of free surfaces on the flow stress of the material has been studied. The results clearly showed a higher force with increased closeness to the free surface and with increased dislocation segment length. The simulations’ results also show a softening effect on the flow stress results due to the effect of the free surfaces.

关键词： Free Surfaces Dislocation Theory Dislocation Dynamics Peach-Koehler Force

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Integration of Spatial Analysis for Tsunami Inundation and Impact Assessment

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Journal of Geographic Information System 2014年第1期6卷 11-22页

作者： abu bakar Sambah Fusanori Miura Graduate School of Science and Engineering Yamaguchi University Ube Japan Graduate School of Science and Engineering Yamaguchi University Ube Japan Fisheries and Marine Science Faculty Brawijaya University Malang Indonesia

Disaster mitigation and reconstruction plan due to tsunami can be implemented with various actions. An integration of spatial analysis through Geographical Information System (GIS) application and multi-criteria analysis through Analytical Hierarchy Process (AHP) is one of the methods for tsunami inundation and impact assessment. In this study, vulnerability, inundation and impact assessment due to tsunami hazard in Ofunato city, Iwate Prefecture, Japan was carried out. Appropriate input parameters were derived from Digital Elevation Model data, and satellite remote sensing and field data were analyzed through GIS. We applied the parameter of elevation and slope created from Aster GDEM version 2, coastline distance created from vector map of the study area and vegetation density created from ALOS ANVIR-2 image. We applied AHP process for weighting the parameter through pair-wise comparison using five iterations of normalized matrix. Five classes of vulnerability were defined and analyzed for tsunami inundation mapping. We used weighted overlay through spatial analyst in GIS to create the final map of tsunami vulnerability. The assessment results indicate that 7.39 square kilometer of the study area was under the high vulnerability zone due to tsunami, and 8.13 square kilometer of building area was under the inundation area. Our result showed good agreement with the observed data and historical map. The result presented here can aid as preliminary information for the coastal zone management related to disaster mitigation and for the evacuation process and management strategy during disaster.

关键词： Spatial Analysis GIS AHP Tsunami

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Transgenerational phenotypic plasticity of diapause induction and related fitness cost in a commercial strain of the parasitoid Aphidius ervi Haliday

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Insect Science 2021年第3期28卷 780-792页

作者： Muhammad Mubashir Saeed Kevin Tougeron abu bakar Muhammad Raza Muhammad Afzal Anjum Aqueel Guillaume Jean Le Goff Frangois Renoz Jennifer Pirotte Thierry Hance Department of Entomology University College of AgricultureUniversity of SargodhaSargodhaPakistan Earth and Life Institute Biodiversity Research CentreUniversite catholique de LouvainLouvain-la-Neuve1348Belgium

Diapause is an adaptation that insects have evolved to synchronize their life cycle with that of seasonal climatic changes and resources ***,cues for its induction are not always clear and,in some cases,a maternal effect may be *** the population level,just a part of the individuals may exhibit diapause with important consequences in terms of winter ***,clear indicators of diapause state are difficult to *** induction was thus investigated in the aphid parasitoid species Aphidius ervi Haliday(Hymenoptera:Braconidae)developing in the aphid Sitobion avenae(Hemiptera:Aphididae)at four crossed photothermal regimes(16℃and 8℃,16:8 h L:D and 8:16 h L:D),and during 2 successive *** analyzed the reliability of changes in mummy color to assess for the diapausing state compared to dissections,and we measured parasitoid morphological and physiological *** observed that the proportion of dark brown mummies increased after one generation under low photothermal regime compared to other *** diapause was recorded at 16℃,16:8 h L:D,while we observed 16.2%and 67.5%diapause incidence at 8℃,8:16 h L:D,at 1st and 2nd generation,*** induction is thus increased by short day-length conditions and low temperatures as well as by maternal *** parasitoid life-history traits(weight,size,fat content,water content,egg-load,and longevity)were affected by the photothermal regime and/or the *** results raise new questions on the environmental thresholds needed to induce diapause and on survival and adaptation potential of commercially available parasitoid strains in different environments.

关键词： dormancy life-history traits mummy color photothermal regimes transgenerational plasticity

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Fraud Prevention Mechanisms of Malaysian Government-Linked Companies： An Assessment of Existence and Effectiveness

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Journal of Modern Accounting and Auditing 2012年第1期8卷 15-31页

作者： Normah Omar Katerina Maria abu bakar Universiti Teknologi MARA Selangor Malaysia

Understanding the root causes of fraud and learning about the most effective fraud prevention mechanisms are critical in reducing the incidence of financial fraud. Therefore, this study solicits the views of fraud investigators on the existence and effectiveness of fraud prevention mechanisms within Government-Linked Companies （GLCs）. Specifically, effective fraud prevention mechanisms （FPM） should be undertaken by five critical groups, namely the board of directors, audit committees, external auditors, internal auditors, and anti-fraud specialists. A total of 147 questionnaires were distributed to fraud investigators of all public listed GLCs in Malaysia. Out of those, a total of 45 usable responses were received, which represents an effective response rate of 30.6%. In terms of existence, the respondents ranked ＂management review of internal controls＂ and ＂external audits of financial statements＂ as the top-most FPMs. This was followed by other mechanisms such as operational audits, internal audits and internal control review/improvements by departments. Out of the 27 fraud prevention mechanisms, fraud investigators perceiyed surprise audits, fraud hotline, fraud prevention program and training, anti-fraud policy, fraud vulnerability reviews, operational audits, whistle-blowing policy, internal audit or fraud examination department, and, imposing penalty and disciplinary action as more effective than the others. Overall, this study provides important insights to practitioners and organizations in identifying fraud prevention mechanisms that are most effective.

关键词： fraud prevention mechanism (FPM) financial fraud government-linked companies (GLCs)

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Methyl gallate isolated from Mangifera pajang kernel induces proliferation inhibition and apoptosis in MCF-7 breast cancer cells via oxidative stress

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Asian Pacific Journal of Tropical Biomedicine 2022年第4期12卷 175-184页

作者： Ranneh Yazan abu bakar Mohd Fadzelly Rahim Azlen-Che Kassim Nur Kartinee Stanslas Johnson Teh Yuan-Han Fadel Abdulmannan Ellulu Mohammed S Department of Technology and Natural Resources Faculty of Applied Science and TechnologyUniversiti Tun Hussein Onn MalaysiaPagoh CampusKM1 Panchor RoadMuar JohorMalaysia Department of Chemistry Faculty of ScienceUniversiti Putra MalaysiaSerdang 43300Malaysia Department of Medicine Faculty of Medicine and Health SciencesUniversiti Putra MalaysiaSelangorMalaysia Sport and Exercises Sciences School Faculty of ScienceLiverpool John Moores UniversityLiverpoolUK Department of Clinical Nutrition Faculty of Applied Medical SciencesAl-Azhar University of GazaGaza CityState of Palestine

Objective:To determine the lead bioactive compound in kernel extract of Mangifera pajang and its anti-cancer activity against human breast cancer cell lines with positive estrogen receptor(MCF-7).Methods:The methanolic extract of dried powder kernel of Mangifera pajang was exposed to column chromatography for *** structural elucidation of the isolated compound was characterized using infrared,nuclear magnetic resonance,mass ***,cytotoxicity,morphological changes,flow cytometry and cell cycle arrest analyses were performed to examine the mechanism of anti-proliferation and apoptosis induced by methyl gallate against ***:One compound was isolated from the methanolic extract of Mangifera pajang kernel and identified as methyl *** flow cytometric results demonstrated induction of apoptosis in MCF-7 cells by three concentrations of methyl *** cell cycle arrest showed a significant(P<0.05)decrease in cell progression at G2/M phase of MCF-7 after treatment with 100μM of methyl *** cell percentage of early and late apoptosis was significant at 10 and 100μM of methyl ***,methyl gallate treatment induced up-regulation of reactive oxygen species levels in MCF-7 cells with a reduction in superoxide dismutase ***:These findings indicate that isolated methyl gallate from Mangifera pajang kernel extracts induces growth inhibition and apoptosis in MCF-7 cells via up-regulating oxidative stress pathway.

关键词： Mangifera pajang Methyl gallate Breast cancer Cell cycle Apoptosis Oxidative stress

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Tritrophic interactions between parasitoids and cereal aphids are mediated by nitrogen fertilizer

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Insect Science 2015年第6期22卷 813-820页

作者： Muhammad A. Aqueel abu-bakar M. Raza Rashad M. Balal Muhammad A. Shahid Irfan Mustafa Muhammad M. Javaid simon R. Leather Division of Biology Imperial College London Silwood Park Campus Ascot SL5 7PY UK University College of Agriculture Department of Biological Sciences University of Sargodha Pakistan Department of Crop and Environment Sciences Harper Adams UniversityShropshire TFIO 8NB UK

Host plant nutritional quality can directly and indirectly affect the third trophic levels. The aphid-parasitoid relationship provides an ideal system to investigate tritrophic interactions （as the parasitoids are completely dependent for their development upon their hosts） and assess the bottom up forces operating at different concentrations of nitrogen applications. The effects of varying nitrogen fertilizer on the performance of Aphidius colemani （V.） reared on Sitobion avenae （E） and Aphidius rhopalosiphi （D.） reared on Rhopalosiphum padi （L.） were measured. Parasitism and percent emergence ofparasitoids were positively affected by nitrogen fertilizer treatments while developmental duration （egg, larval, and pupal stages） was not affected by increasing nitrogen inputs. In males and females of both parasitoid species, adult longevity increased with the increasing nitrogen fertilizer. Hind tibia length and mummy weight of both parasitoid species increased with nitrogen fertilizer concentrations, as a result of larger aphids. This study showed that nitrogen application to the soil can have important consequences for aboveground multitrophic interactions.

关键词： cereal aphid parasitoids nitrogen fertilization tritrophic interactions

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Void Growth and Interaction in a Structural Aluminum Alloy: Experiments and Theory

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Journal of Minerals and Materials Characterization and Engineering 2021年第1期9卷 14-37页

作者： Scott Gampert abu bakar Siddique Tariq A. Khraishi Mechanical Engineering Department University of New Mexico Albuquerque USA

The problem of void growth and interaction is of importance to understanding the mechanics of failure in metals exhibiting ductility. In this work, the growth and interaction of voids in 6061-T6 aluminum were studied experimentally. Specifically, holes of varying numbers and relative placement were investigated for their normalized area growth with applied displacement. Flat dog-bone specimens were carefully drilled in their gauge area with no (zero) holes, one hole, and two holes (arranged vertically or horizontally) for experimentation after polishing. The growth of holes, captured by video recordings, exhibited exponential behavior and was influenced greatly by the number and arrangement of holes with the horizontal voids growing the fastest and the vertical ones growing the slowest. Also, the ensuring deformation of the sample was studied using load-displacement curves, pictography and videography, SEM imaging and Atomic Force Microscopy (AFM). The methods revealed that although the major part failure is due to large crack formation, it was preceded by intense dislocation slip activity and the formation of micro cavities. Also, the AFM quantified the three-dimensional nature of crystal or grain deformation and how it is greatly influenced by distance and location from the hole. Lastly, theoretical understanding of hole growth was offered.

关键词： Voids Holes Stress Concentration Void Growth Void Interaction

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