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Chinese Journal of Chemistry 2011年第4期29卷 643-649页

作者： Ahmed, khalid Azmat, Rafia Uddin, Fahim Fatmi, M. Qaiser Department of Chemistry University of Karachi Karachi 752 70 Pakistan Department of Chemistry Jinnah University for Women Nazimabad Karachi Pakistan Department of Chemistry University of California at Riverside California 92521 USA

The reaction between the thionine （Th） and the ribose was observed spectrophotometrically and changes in absorbance of Th were recorded at variable concentration of dye, reductant and pH. A pseudo first order rate of reaction was found to establish the reduction kinetics of the dye, studied at a pH range of 0.34 to 12.8. Absorption spectrum of Th at different pH, with ribose showed a pH （12.8） dependent introversion. The reduction most probably took place with enediol intermediate of the sugar at high pH. A full geometry optimization of predominant species of Th namely, mono-deprotonated, di-deprotonated Th, and LTh （leuco thionine） respectively, at low and high pH, was performed at B3LYP level of theory. The data obtained from the energy minimization were in excellent agreement with other experimental and theoretical observations. The calculated enthalpies of formation for both reduction reactions （mono-deprotonated Th＋H＋→leucothionine and di-deprotonated Th＋2H＋→leucothionine） provided evidences for maximum reduction of the dye at high pH.

关键词： thionine ribose pH enediol geometry optimization reduction

Estimates and burden of foodborne pathogens in RTE beverages in relation to vending practices

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Food Quality and Safety 2019年第2期3卷 107-115页

作者： Asma Afreen Zaheer Ahmed Hajra Ahmad Nauman khalid Department of Home and Health Sciences Research ComplexAllama Iqbal Open UniversityIslamabadPakistan School of Food and Agricultural Sciences University of Management and TechnologyLahorePakistan

Objectives:Growing trend of street-vended food in underdeveloped countries offers low-cost food to many sections of *** it provides job opportunities to many urban dwellers,several health hazards are associated with this *** present study investigates the burden of foodborne pathogens in Ready-To-Eat(RTE)beverages in relation to vending practices among street vendors of Rawalpindi City,Pakistan according to standardized methods and *** and Methods:Six densely populated locations of Rawalpindi city were *** consumed sugar cane juice(SCJ)and tamarind prune(dried plums)drink(TPD)(locally called as Imli Alu Bukhara sherbet)from five vendors from each location were chosen in summer season where the temperature reaches above 40℃.Mean and the standard deviation were obtained by univariate and bivariate *** between the study variables was assessed through cross-tabulations,chi-square,and correlation ***:All the samples were found unsatisfactory in comparison to guidelines of aerobic plate *** coliform was observed in 86.7 per cent of SCJ and 70.0 per cent of TPD *** samples of SCJ exceeded the limit of>1100 MPN/ml value,whereas samples of TPD exceeded this limit for Escherichia *** of SCJ and 93.3 per cent of TPD samples depicted the presence of Salmonella *** *** found significantly high in 73.3 per cent samples of SCJ and 23.3 per cent samples of ***:The incidence of high bioloads attributes towards a potential reservoir of foodborne pathogens due to unhygienic vending practices.

关键词： Ready-To-Eat beverages foodborne pathogens street vendors vending practices

Managing Delivery of Safeguarding Substances as a Mitigation Against Outbreaks of Pandemics

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Computers, Materials & Continua 2021年第7期68卷 1161-1181页

作者： Said Ali Hassan khalid Alnowibet Prachi Agrawal Ali Wagdy Mohamed Department of Operations Research and Decision Support Faculty of Computers and Articial IntelligenceCairo UniversityGiza12613Egypt Department of Statistics and Operations Research College of ScienceKing Saud UniversityRiyadhSaudi Arabia Trafc Safety Technologies Chair Vice Deanship of Scientic ResearchKing Saud UniversityRiyadhSaudi Arabia Department of Mathematics and Scientic Computing National Institute of TechnologyHamirpur177005India Operations Research Department Faculty of Graduate Studies for Statistical ResearchCairo UniversityGiza12613Egypt School of Engineering and Applied Sciences Wireless Intelligent Networks Center(WINC)Nile UniversityGizaEgypt

The optimum delivery of safeguarding substances is a major part of supply chain management and a crucial issue in the mitigation against the outbreak of pandemics.A problem arises for a decision maker who wants to optimally choose a subset of candidate consumers to maximize the distributed quantities of the needed safeguarding substances within a specic time period.A nonlinear binary mathematical programming model for the problem is *** decision variables are binary ones that represent whether to choose a specic consumer,and design constraints are formulated to keep track of the chosen *** better illustrate the problem,objective,and problem constraints,a real application case study is *** case study involves the optimum delivery of safeguarding substances to several hospitals in the Al-Gharbia Governorate in *** hospitals are selected to represent the consumers of safeguarding substances,as they are the rst crucial frontline for mitigation against a pandemic outbreak.A distribution truck is used to distribute the substances from the main store to the hospitals in specied required quantities during a given working *** objective function is formulated in order to maximize the total amount of delivered quantities during the specied time *** case study is solved using a novel Discrete Binary Gaining Sharing Knowledge-based Optimization algorithm(DBGSK),which involves two main stages:discrete binary junior and senior gaining and sharing *** has the ability of nding the solutions of the introduced problem,and the obtained results demonstrate robustness and convergence toward the optimal solutions.

关键词： Safeguarding substances mitigation against pandemic outbreaks supply chain management metaheuristic optimization

Role of flavonoids in plant interactions with the environment and against human pathogens-A review

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Journal of Integrative Agriculture 2019年第1期18卷 211-230页

作者： Muhammad khalid Saeed-ur-Rahman Muhammad Bilal HUANG Dan-feng School of Agriculture and Biology Shanghai Jiao Tong University School of Life Science and Food Engineering Huaiyin Institute of Technology

Flavonoids are widely-distributed polyphenolic secondary metabolites with diverse biological activities in plants and benefit human health as protective dietary *** participate in plants' responses to harsh environmental conditions and effectively regulate the cell differentiation and *** plants,the majority of their functions are attributed to their strong antioxidative ***,dietary flavonoids protect the human body against free radicals which are associated with the development of cancer and *** rich in polyphenols have been used to cure various diseases because of their antibacterial,antiviral,antifungal and anticancer *** review summarizes the up-to-date research trends and development on flavonoids and its derivatives,working mechanisms and potential functions and applications particularly in relation to plant protection and human *** the end,notable concluding remarks with a close-up look at the future research directions have also been presented briefly.

关键词： flavonoids structure and composition biological activity plant protection human health antimicrobial

Regulating the fate of stem cells for regenerating the intervertebral disc degeneration

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World Journal of Stem Cells 2021年第12期13卷 1881-1904页

作者： Sobia Ekram Shumaila khalid Asmat Salim Irfan Khan Dr.Panjwani Center for Molecular Medicine and Drug Research International Center for Chemical and Biological SciencesUniversity of KarachiKarachi 75270SindhPakistan

Lower back pain is a leading cause of disability and is one of the reasons for the substantial socioeconomic *** etiology of intervertebral disc(IVD)degeneration is complicated,and its mechanism is still not completely *** such as aging,systemic inflammation,biochemical mediators,toxic environmental factors,physical injuries,and genetic factors are involved in the progression of its ***,no therapy for restoring degenerated IVD is available except pain management,reduced physical activities,and surgical ***,it is imperative to establish regenerative medicine-based approaches to heal and repair the injured disc,repopulate the cell types to retain water content,synthesize extracellular matrix,and strengthen the disc to restore normal spine *** therapy has gained attention for IVD management as an alternative therapeutic *** this review,we present an overview of the anatomical and molecular structure and the surrounding pathophysiology of the *** therapeutic approaches,including proteins and growth factors,cellular and gene therapy,and cell fate regulators are ***,small molecules that modulate the fate of stem cells for their differentiation into chondrocytes and notochordal cell types are highlighted.

关键词： Stem cell Intervertebral disc Degeneration Inflammation Cell therapy Gene modification

Optimum Location of Field Hospitals for COVID-19: A Nonlinear Binary Metaheuristic Algorithm

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Computers, Materials & Continua 2021年第7期68卷 1183-1202页

作者： Said Ali Hassan khalid Alnowibet Prachi Agrawal Ali Wagdy Mohamed Department of Operations Research and Decision Support Faculty of Computers and Artificial IntelligenceCairo UniversityGiza12613Egypt College of Science Department of Statistics and Operations ResearchKing Saud UniversityRiyadhSaudi Arabia Department of Mathematics and Scientific Computing National Institute of Technology HamirpurHimachal Pradesh177005India Department of Operations Research Faculty of Graduate Studies for Statistical ResearchCairo UniversityGiza12613Egypt Wireless Intelligent Networks Center(WINC) School of Engineering and Applied SciencesNile UniversityGizaEgypt

Determining the optimum location of facilities is critical in many fields,particularly in *** study proposes the application of a suitable location model for field hospitals during the novel coronavirus 2019(COVID-19)*** used model is the most appropriate among the three most common location models utilized to solve healthcare problems(the set covering model,the maximal covering model,and the P-median model).The proposed nonlinear binary constrained model is a slight modification of the maximal covering model with a set of nonlinear *** model is used to determine the optimum location of field hospitals for COVID-19 risk *** designed mathematical model and the solution method are used to deploy field hospitals in eight governorates in Upper *** this case study,a discrete binary gaining–sharing knowledge-based optimization(DBGSK)algorithm is *** DBGSK algorithm is based on how humans acquire and share knowledge throughout their *** DBGSK algorithm mainly depends on two junior and senior binary *** two stages enable DBGSK to explore and exploit the search space efficiently and effectively,and thus it can solve problems in binary space.

关键词： Facility location nonlinear binary model field hospitals for COVID-19 gaining-sharing knowledge-based metaheuristic algorithm

Synthesis and Spectral Properties of 4-（2,5-Dimethoxyphenyl- methelene）-2-phenyl-5-oxazolone （DMPO）

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Chinese Journal of Chemistry 2012年第3期30卷 563-569页

作者： EI-Daly, Samy A Asiri, Abdullah M Alamry, khalid A Hussein, Mahmoud A Chemistry Department Faculty of Science King Abdulaziz University P.O. Box 80203 Jeddah 21589 Saudi Arabia The Center of Excellence for Advanced Materials King Abdulaziz University Jeddah 21589 P.O. Box 80203 Saudi Arabia Department of Chemistry Faculty of Science Tanta University 31527 Tanta Egypt Chemistry Department Faculty of Science Assiut University Assiut 71516 Egypt

An interesting flourophore, 4-（2,5-dimethoxyphenylmethelene）-2-phenyl-5-oxazolone （DMPO） was synthesized by mixing an equivalent molar quantity of hippuric acid and 2,5-dimethoxybenzaldehyde in acetic anhydride in the presence of anhydrous sodium acetate. The absorption and fluorescence characteristics of 4-（2,5-dimethoxy-phenyl- methelene）-2-phenyl-5-oxazolone （DMPO） were investigated in different solvents. DMPO dye exhibits red shift in both absorption and emission spectra as solvent polarity increases, indicating change in the dipole moment of mole- cules upon excitation due to an intramolecular charge transfer interaction. The fluorescence quantum yield depends strongly on the properties of the solvents, which was attributed to positive and negative solvatokinetic effects. A crystalline solid of DMPO gave strong excimer like emission at 630 nm due to the excitation of molecular aggregates. This is expected from the idealized crystal structure of the dye that belongs to the B-type class of Steven＇s Classifica- tion. DMPO displayed fluorescence quenching by triethylamine via nonemissive exciplex formation.

关键词： 4-(2,5-dimethoxy-phenylmethelene)-2-phenyl-5-oxazolone (DMPO) effect of medium fluorescencequantum yield solid state emission

Impact of soil compaction on the engineering properties of potato tubers

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International Journal of Agricultural and Biological Engineering 2020年第2期13卷 163-167页

作者： Mohamed K.Edrris khalid A.Al-Gaadi Abdalhaleem A.Hassaballa ElKamil Tola khalid A.M.Ahmed Precision Agriculture Research Chair King Saud UniversityRiyadh 11451Saudi Arabia Department of Agricultural Engineering College of Food and Agriculture SciencesKing Saud UniversityRiyadh 11451Saudi Arabia Department of Agricultural&Biological Engineering Faculty of EngineeringKhartoum UniversityKhartoumSudan Chair of Dates Industry and Technology King Saud UniversityRiyadh 11451Saudi Arabia

A study on a 30 hm2 field was conducted to assess the variability in soil compaction and to investigate its effect on the engineering properties of potato tubers in terms of tuber shape and key dimensions(length,width and thickness)and resistance to penetration,rupture and shear *** soil compaction levels were spatially correlated with the engineering properties of potato tubers through linear regression and ANOVA *** three compaction levels included a low level(C1)ranging between 1.2-1.9 MPa,a medium level(C2)with compaction levels between 2.0-2.3 MPa and a high level(C3)ranging between 2.4-2.9 *** revealed that there were no significant changes in the key tuber dimensions corresponding to the variability in soil ***,inverse linear relationships were observed between soil compaction and the key tuber dimensions with R2 values of 77%,97%and 96%for length,width and thickness,***,the soil compaction was shown to have no effect on the tuber resistance to compression and shear *** contrast,the tuber resistance to penetration was significantly affected by soil compaction(p>F=0.0012).

关键词： compaction potato tubers precision agriculture potato engineering properties

A transparent, conducting tape for flexible electronics

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Nano Research 2016年第4期9卷 917-924页

作者： Ya Huang Suiyang Liao Jie Ren Bilal khalid Hailin Peng Hui Wu State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing 100084 China Center for Nanochemistry Beijing Science and Engineering Center for Nanocarbons Beijing National Laboratory for Molecular Sciences (BNLMS) College of Chemistry and Molecular Engineering Peking University Beijing 100871 China

Transparent electrodes are essential components for optoelectronic devices such as displays and thin-film solar cells. Traditionally, the deposition of transparent conducting layers and the sealing of the device are separate steps. Here we report on a highly transparent, conductive, and flexible ＂tape＂, which can be obtained by transferring silver nanowire networks to conventional transparent tape. We utilized the viscidity of the tape to reduce the junction resistance between silver nanowires and further protect the nanowires from corrosion, oxidation and mechanical damage. By this simple method, we obtained a flexible tape with high transparency （-90% at 550 nm wavelength） and low sheet resistance （approaching 22 Ω.sq^-1）. The transparent tape can be attached and stuck firmly on complex surfaces, making the surface highly conductive. We demonstrated the use of the tape as both a conducting layer and a sealing layer for flexible electronics applications including in-situ temperature monitoring and electrochromic devices.

关键词： transparent electrode silver nanowires tape flexible electronics

N1-soliton solution for Schrodinger equation with competing weakly nonlocal and parabolic law nonlinearities

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Communications in Theoretical Physics 2020年第6期72卷 129-135页

作者： Mohammed O Al-Amr Hadi Rezazadeh khalid K Ali Alper Korkmazki Department of Mathematics College of Computer Sciences and MathematicsUniversity of MosulMosul 41002Iraq Faculty of Engineering Technology Amol University of Special Modern TechnologiesAmolIran Mathematics Department Faculty of ScienceAl-Azhar UniversityNasr-CityCairoEgypt Nord StaBe 9 WeimarGermany

The nonlocal nonlinear Schr?dinger equation(NNLSE)with competing weakly nonlocal nonlinearity and parabolic law nonlinearity is explored in the current work.A powerful integration tool,which is a modified form of the simple equation method,is used to construct the dark and singular 1-soliton *** is shown that the modified simple equation method provides an effective and powerful mathematical gadget for solving various types of NNLSEs.

关键词： Schrodinger equation soliton integrability modified simple equation method