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283篇 您的检索式:作者名="Muhammad IMRAN"
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1Crosstalk of liver immune cells and cell death mechanisms in different murine models of liver injury and its clinical relevance显示文摘BACKGROUND: Liver inflammation or hepatitis is a result of pluripotent interactions of cell death molecules, cytokines, chemokines and the resident immune cells collectively called as microenvironment. The interplay of these inflammatory mediators and switching of immune responses during hepatotoxic, viral, drug-induced and immune cell-mediated hepatitis decide the fate of liver pathology. The present review aimed to describe the mechanisms of liver injury, its relevance to human liver pathology and insights for the future therapeutic interventions.DATA SOURCES: The data of mouse hepatic models and relevant human liver diseases presented in this review are systematically collected from Pub Med, Science Direct and the Web of Science databases published in English. RESULTS: The hepatotoxic liver injury in mice induced by the metabolites of CCl4, acetaminophen or alcohol represent necrotic cell death with activation of cytochrome pathway, formation of reactive oxygen species(ROS) and mitochondrial damage. The Fas or TNF-α induced apoptotic liver injury was dependent on activation of caspases, release of cytochrome c and apoptosome formation. The Con A-hepatitis demonstrated the involvement of TRAIL-dependent necrotic/necroptotic cell death with activation of RIPK1/3. The α-Gal Cer-induced liver injury was mediated by TNF-α. The LPS-induced hepatitis involved TNF-α, Fas/Fas L, and perforin/granzyme cell death pathways. The MHV3 or Poly(I:C) induced liver injury was mediated by natural killer cells and TNF-α signaling. The necrotic ischemia-reperfusion liver injury was mediated byhypoxia, ROS, and pro-inflammatory cytokines; however, necroptotic cell death was found in partial hepatectomy. The crucial role of immune cells and cell death mediators in viral hepatitis(HBV, HCV), drug-induced liver injury, non-alcoholic fatty liver disease and alcoholic liver disease in human were discussed.CONCLUSIONS: The mouse animal models of hepatitis provide a parallel approach for the study of human liver pathology. Blocking or stimulating the pathways associated with liver cell death could unveil the novel therapeutic strategies in the management of liver diseases.Hilal Ahmad Khan Muhammad Zishan Ahmad Junaid Ali Khan Muhammad Imran Arshad 2017Hepatobiliary & Pancreatic Diseases International2017,16,3:24
2长期施肥对棕壤有机碳储量及固碳速率的影响显示文摘利用棕壤肥料长期定位试验,研究了不同施肥条件下棕壤有机碳在0~60 cm土层的含量和储量特征以及土壤固碳速率.试验共设6个处理,即氮磷肥有机肥配施(M_2NP)、氮肥有机肥配施(M_2N)、单施有机肥(M_2)、单施氮肥(N)、氮磷肥配施(NP)和不施肥处理(CK).结果表明:经过31年长期不同施肥,各处理土壤有机碳(SOC)含量和储量的剖面分布均呈现随土层深度增加而显著降低的规律.本试验条件下M_2NP、M_2N、M_2、NP、N、CK处理的耕层有机碳富集系数分别为0.465、0.455、0.407、0.48_2、0.393、0.471,表明耕层土壤对有机碳的保持强度最强.在0~60 cm土层土壤有机碳储量表现为M_2NP、M_2N>M_2、NP>N>CK,有机肥和化肥配施能够显著提高土壤有机碳含量和储量.与试验前相比,CK处理各土层土壤有机碳含量和储量均显著降低.各处理碳库管理指数(CPMI)表现为M_2NP>M_2N>M_2>N>NP>CK.分析不同施肥处理土壤固碳速率可知,与试验前相比,CK处理表现为碳的净释放,固碳速率达-401.4 kg·hm^(-_2)·a^(-1);固碳速率最高的为M_2NP,M_2N,分别达到489kg·hm^(-_2)·a^(-1)、440._2 kg·hm^(-_2)·a^(-1).综合结果表明,化肥、有机肥配施所产生交互效应更有利于棕壤有机碳储量的增加及固碳速率的提高.兰宇 Muhammad Imran Asshraf 韩晓日 杨劲峰 吴正超 王月 李娜 2016环境科学学报2016,36,1:21
3Hepatitis B virus therapy:What's the future holding for us?显示文摘Hepatitis B is one of the leading causes of liver cancer worldwide and unfortunately the number of people affected with hepatitis B virus(HBV) infection is still on the rise. Although the HBV has been known to cause fatal illness since decades but the population effected by this lethal virus have still only a few options for its management. The major treatment strategies include interferons and nucleos(t)ide analogues. These agents have so far produced unsatisfactory results in terms of complete virus eradication. Interferons cannot be used for long term therapy because of their potential side effects. Prolong treatment with nucleos(t)ide analogues has also been reported to cause serious side effects besides the increasing resistance by the virus. The need for new innovative solutions for treatment of HBV has been realized by global research institutes and pharmaceutical industry. Present review focuses in detail on the new ideas that are being transformed into therapeutic tools for use as future therapies in HBV infection. Modern drug designing and screening methods have made the drug discovery process shorter and more reliable. HBV therapeutics will take a new turn in coming years owing to these intelligent drug designing and screening methods. Future therapy of HBV is aiming to include the use of vaccines(both prophylactic and therapeutic), immunomodulators such as antibodies, non-nucleoside antivirals such as RNAi and inhibitors of viral life cycle.Sobia Manzoor Muhammad Saalim Muhammad Imran Saleha Resham Javed Ashraf 2015World Journal of Gastroenterology2015,21,44:9
4Challenges against CO_(2) abatement strategies in cement industry: A review显示文摘Cement industry is an intensive source of fuel consumption and greenhouse gases(GHGs) emissions. This industry is responsible for 5% of GHGs emissions and is among the top industrial sources of carbon dioxide(CO_(2)) emissions. Therefore, CO_(2) emissions reduction from cement production process has been always an appealing subject for researches in universities and industry. Various efforts have been carried out to mitigate the huge mass of CO_(2) emissions from the cement industry. Although, majority of these strategies are technically viable, due to various barriers, the level of CO_(2) mitigation in cement industry is still not satisfactory. Among numerous researches on this topic, only a few have tried to answer why CO_(2) abatement strategies are not globally practiced yet. This work aims to highlight the challenges and barriers against widespread and effective implementation of CO_(2) mitigation strategies in the cement industry and to propose practical solutions to overcome such barriers.Emad Benhelal Ezzatollah Shamsaei Muhammad Imran Rashid 2021Journal of Environmental Sciences2021,33,6:8
5Hepatitis C virus NS5A promotes insulin resistance through IRS-1 serine phosphorylation and increased gluconeogenesis显示文摘AIM: To investigate the mechanisms of insulin resistance in human hepatoma cells expressing hepatitis C virus(HCV) nonstructural protein 5A(NS5A).METHODS: The human hepatoma cell lines,Huh7 and Huh7.5,were infected with HCV or transientlytransfected with a vector expressing HCV NS5 A. The effect of HCV NS5 A on the status of the critical players involved in insulin signaling was analyzed using realtime quantitative polymerase chain reaction and Western blot assays. Data were analyzed using Graph Pad Prism version 5.0.RESULTS: To investigate the effect of insulin treatment on the players involved in insulin signaling pathway,we analyzed the status of insulin receptor substrate-1(IRS-1) phosphorylation in HCV infected cells or Huh7.5 cells transfected with an HCV NS5 A expression vector. Our results indicated that there was an increased phosphorylation of IRS-1(Ser307) in HCV infected or NS5 A transfected Huh7.5 cells compared to their respective controls. Furthermore,an increased phosphorylation of Akt(Ser473) was observed in HCV infected and NS5 A transfected cells compared to their mock infected cells. In contrast,we observed decreased phosphorylation of Akt Thr308 phosphorylation in HCV NS5 A transfected cells. These results suggest that Huh7.5 cells either infected with HCV or ectopically expressing HCV NS5 A alone have the potential to induce insulin resistance by the phosphorylation of IRS-1 at serine residue(Ser307) followed by decreased phosphorylation of Akt Thr308,Fox01 Ser256 and GSK3β Ser9,the downstream players of the insulin signalingpathway. Furthermore,increased expression of PECK and glucose-6-phosphatase,the molecules involved in gluconeogenesis,in HCV NS5 A transfected cells was observed.CONCLUSION: Taken together,our results suggest the role of HCV NS5 A in the induction of insulin resistance by modulating various cellular targets involved in the insulin signaling pathway.Fahed Parvaiz Sobia Manzoor Jawed Iqbal Mehuli Sarkar-Dutta Muhammad Imran Gulam Waris 2015World Journal of Gastroenterology2015,21,43:7
6改革开放后我国产业转移方向实证研究显示文摘采用省际数据,实证分析了我国东部地区各省份之间的区域经济空间相关性,结论表明:东部各省份的区域经济发展一体化程度较高,同时发现相邻省份中具有共同边界的区域其经济发展相关性也较高。以此为基础,使用1978-2014年的总体工业数据,借助工业净产值份额和第二产业劳动力就业份额两个指标,研究并测度了改革开放后我国产业的转移方向,结论表明:(1)从改革开放后的1978到2003年这段时期内,我国几乎没有发生东西方向上的产业转移,但在2003—2013年则发生了由东向西的制造业产业转移现象,同时向中部转移的幅度大于向西部转移的幅度,随后这一转移趋势又发生'逆转';(2)在东部地区内部发生了由北向南的产业转移现象,此外上海作为初始工业化程度较高的地域,产业转移方向表现为南北两个方向;(3)与实证分析相对应,距离越近产业转移速度越快。最后,得出将东部地区作为我国经济运行主部的结论,而中西部则要发挥比较优势、承接相关产业、积极参与东部分工体系、推动自身经济发展。安虎森 郑文光 Muhammad Imran 2017贵州社会科学2017,,6:6
7区域经济结构转型升级机理分析显示文摘高技能劳动力的转移和空间聚集有助于提升聚集区厂商的创新能力和技术水平,使这些产业部门逐渐发展成为新兴产业部门。新兴产业部门具有较高的技术水平和劳动生产率,且单位土地产值高于传统产业部门。在优势区位竞争中,这些高单位土地产值的新兴产业部门将挤走原有的传统产业部门,使原有传统产业部门的生产区位变成高生产率的新兴产业部门的生产区位,被挤出的传统部门则转移到土地价格相对便宜的市郊或边远地区甚至被淘汰。由技术水平提升导致的区域经济总量的增加,意味着区域经济增长;原有低效率的传统产业部门被高效率的新兴产业部门取代,意味着区域经济结构的转型升级;高效率的新兴部门挤出低效率的传统产业部门,意味着产业的区际转移,这就是区域经济结构演进的基本机理。安虎森 Muhammad Imran 2017天津社会科学2017,,2:6
8Estimating the basic reproductive ratio for the Ebola outbreak in Liberia and Sierra Leone显示文摘Background:Ebola virus disease has reemerged as a major public health crisis in Africa,with isolated cases also observed globally,during the current outbreak.Methods:To estimate the basic reproductive ratio R0,which is a measure of the severity of the outbreak,we developed a SEIR(susceptible-exposed-infected-recovered)type deterministic model,and used data from the Centers for Disease Control and Prevention(CDC),for the Ebola outbreak in Liberia and Sierra Leone.Two different data sets are available:one with raw reported data and one with corrected data(as the CDC suspects under-reporting).Results:Using a deterministic ordinary differential equation transmission model for Ebola epidemic,the basic reproductive ratio R0 for Liberia resulted to be 1.757 and 1.9 for corrected and uncorrected case data,respectively.For Sierra Leone,R0 resulted to be 1.492 and 1.362 for corrected and uncorrected case data,respectively.In each of the two cases we considered,the estimate for the basic reproductive ratio was initially greater than unity leading to an epidemic outbreak.Conclusion:We obtained robust estimates for the value of R0 associated with the 2014 Ebola outbreak,and showed that there is close agreement between our estimates of R0.Analysis of our model also showed that effective isolation is required,with the contact rate in isolation less than one quarter of that for the infected non-isolated population,and that the fraction of high-risk individuals must be brought to less than 10%of the overall susceptible population,in order to bring the value of R0 to less than 1,and hence control the outbreak.Adnan Khan Mahim Naveed Muhammad Dur-e-Ahmad Mudassar Imran 2015Infectious Diseases of Poverty2015,4,1:5
9温和提取法评估老化前后土壤中菲的生物有效性显示文摘采用温和溶剂提取方法对不同老化时间土壤中的菲进行提取,研究了正丁醇、二氯甲烷、2-羟丙基-β-环糊精(2-Hydroxypropyl-beta cyclodextrin,HPCD)提取量与生物吸收之间的相关性。结果表明,温和有机溶剂(二氯甲烷、正丁醇)提取与温和HPCD提取法对菲的提取量与蚯蚓蓄积量有很好的相关性(p<0.05)。与其他温和试剂提取相比,温和正丁醇提取可以更好地预测菲在土壤中的生物有效性。张聪恺 Muhammad Imran Khan Sardar Alam Cheema 沈超峰 唐先进 申开丽 陈蕾 陈新才 施积炎 陈英旭 2011土壤学报2011,48,1:5
10Dynamic characteristics of nanoindentation in Ni:A molecular dynamics simulation study显示文摘In this work,three-dimensional molecular dynamics simulation is carried out to elucidate the nanoindentation behaviour of single crystal Ni.The substrate indenter system is modelled using hybrid interatomic potentials including the manybody potential(embedded atom method) and two-body Morse potential.The spherical indenter is chosen,and the simulation is performed for different loading rates from 10 m/s to 200 m/s.Results show that the maximum indentation load and hardness of the system increase with the increase of velocity.The effect of indenter size on the nanoindentation response is also analysed.It is found that the maximum indentation load is higher for the large indenter whereas the hardness is higher for the smaller indenter.Dynamic nanoindentation is carried out to investigate the behaviour of Ni substrate to multiple loading-unloading cycles.It is observed from the results that the increase in the number of loading unloading cycles reduces the maximum load and hardness of the Ni substrate.This is attributed to the decrease in recovery force due to defects and dislocations produced after each indentation cycle.Muhammad Imran Fayyaz Hussain Muhammad Rashid S.A.Ahmad 2012Chinese Physics B2012,21,11:4
11Synergistic antibacterial effect of honey and Herba Ocimi Basilici against some bacterial pathogens显示文摘OBJECTIVE: To evaluate the antibacterial activity of the combination of different honey brands and methanolic fraction of Herba Ocimi Basilici using agar well diffusion assay. METHODS: The antibacterial activity was determined against thirteen pathogenic bacterial clinical isolates including six gram negative(Klebsiella pneumonia, Pseudomonas aeroginosa, Escherichia coli, Salmonella typhi, Salmonella typhimirium, Xanthomonas campestris) and six gram positive strains(Enterococcus faecalis faecalis, Bacillus subtilis, Staphylococcus aureus, Clostridium perfringens type C, Clostridium perfringens type D, Clostridium chauvoei). Agar well diffusion method was used while zones of inhibition were measured with vernier scale. RESULTS: At higher concentration, all the honey brands showed good to significant activity. The highest activity was observed for Hamdard brand honey(27.60±0.40) against Enterococcus faecalis. CONCLUSION: These results revealed that combinations of plant extracts of Herba Ocimi Basilici with honey can be used for the development of potent and novel antibacterial agents.Ali Talha Khalil Imran Khan Kafeel Ahmad Yusra Ali Khan Momin Khan Muhammad Jaseem Khan 2013Journal of Traditional Chinese Medicine2013,33,6:4
12Blockchain-enabled resource management and sharing for 6G communications显示文摘The sixth-generation(6G)network must provide better performance than previous generations to meet the requirements of emerging services and applications,such as multi-gigabit transmission rate,higher reliability,and sub-1 ms latency and ubiquitous connection for the Internet of Everything(IoE).However,with the scarcity of spectrum resources,efficient resource management and sharing are crucial to achieving all these ambitious requirements.One possible technology to achieve all this is the blockchain.Because of its inherent properties,the blockchain has recently gained an important position,which is of great significance to the 6G network and other networks.In particular,the integration of the blockchain in 6G will enable the network to monitor and manage resource utilization and sharing efficiently.Hence,in this paper,we discuss the potentials of the blockchain for resource management and sharing in 6G using multiple application scenarios,namely,Internet of things,deviceto-device communications,network slicing,and inter-domain blockchain ecosystems.Hao Xu Paulo Valente Klaine Oluwakayode Onireti Bin Cao Muhammad Imran Lei Zhang 2020Digital Communications and Networks2020,6,3:4
13Mechanical strength of wheat grain varieties influenced by moisture content and loading rate显示文摘Mechanical shear resistance of wheat grain is a significant concern for the designers and researchers related to the design of threshing,handling and processing machinery of the field crops.The grain mechanical properties directly affect the machine geometry and its operational parameters.The present study was carried out to determine the shear resistance of five wheat varieties(Locally names;TD-02,Sindhu-1105,Benazir,China and SKD-118)influenced by moisture content(16.7%,18.7%and 19.5%)and loading rate(3 mm/s,6 mm/s and 9 mm/s).However,some physio-dimensional properties(length,width,thickness,slenderness ratio,surface area and sphericity)were obtained at different moisture contents.The results showed that the shear resistance reduced by increasing the moisture content and loading rate.The average shear resistance decreased from 10.45 N to 3.74 N for 3-9 mm/s loading rate at moisture content of 16.7%to 19.5%.Thus,the maximum correlation(r=0.905)of shear resistance obtained at 16.7%,whereas minimum correlation(r=0.692)obtained at 19.5%.The shear resistance of wheat grain was highly significant(p<0.05)at 9 mm/s for 19.5%.Shear resistance decreased with an increase in the moisture content in the grain whereas deformation is increasing with the increase of moisture content.However,the maximum bulk density of wheat grain obtained at 19.5%for SKD-118,while the minimum obtained at 16.7%for TD-02.It is recommended that the design and modification of wheat grain processing equipment should be executed on the physio-mechanical properties of grain varieties.Yaoming Li Farman Ali Chandio Zheng Ma Imran Ali Lakhiar Abdul Razaque Sahito Fiaz Ahmad Irshad Ali Mari Umer Farooq Muhammad Suleman 2018International Journal of Agricultural and Biological Engineering2018,11,4:4
14石墨烯纳米片增强铝基复合材料的制备与性能显示文摘采用高能球磨、放电等离子烧结以及热挤压工艺制备含量为5.0%(体积分数)的石墨烯增强铝基复合材料。分别采用X射线光电子能谱、透射电镜及拉伸试验研究挤压态复合材料的显微组织与力学性能,发现5.0%(体积分数)的石墨烯分散在铝晶界上,并且未与铝基体发生界面反应。最终,挤压态复合材料的屈服强度和抗拉强度高达462 MPa和479 MPa,分别比挤压态铝基体提高62%和60%。断口分析表明,在断裂过程中复合材料中分散的石墨烯起到明显的载荷传递的作用。上述结果表明,采用高能球磨、放电等离子烧结以及热挤压制备工艺可将高含量石墨烯分散于铝合金中,且能控制石墨烯和铝基体之间的界面反应。郑忠 杨晓霞 李建超 张学习 Imran MUHAMMAD 耿林 2021Transactions of Nonferrous Metals Society of China2021,31,4:3
15Slippery Photothermal Trap for Outstanding Deicing Surfaces显示文摘Ice accumulation is a safety and operational threat in power lines,wind turbines,and transportations.Surfaces having both passive anti-icing and active deicing functionalities are very rare.Here,we report a self-cleaning slippery photothermal trap,which is icephobic passively and deice the surfaces actively by converting sun light to heat at the ice-substrate interface.The photothermal trap consists of three layers:a candle soot layer act as solar radiation absorber,a magnetic iron oxide Fe_(3)O_(4) nanoparticles layer act as heat spreader for lateral dispersal of sun light,and Room Temperature Vulcanized(RTV)insulation to reduce the transverse heat loss.Upon illumination under microsolar 300,the temperature of the surface increased by 40℃ within 200 s.The heat confinement at the magnetic Fe_(3)O_(4) na-noparticles layer leads to rapid increase of the surface temperature,ice start to melt and silicone lubricant facilitates the ice removal.The slippery photothermal trap removed the frozen droplet(10 fiL)within 40 s upon the illumination of sun light and the frozen droplet was completely converted into water after 7 min illumination of solar light at-20℃.The developed slippery photothermal trap also melted the fully frost covered layer within 100 s at-20℃ under sunlamp.The average defrosted length(25 mm)was also observed by irradiation of laser light for 45 s.The self-cleaning slippery photothermal coating showed outstanding deicing performance at subzero temperature for long term due to the infusion of silicone oil into the nanostructures and same chemical composition with binder.Muhammad Imran Jamil Qiongyan Wang Amjad Ali Munir Hussain Tariq Aziz Xiaoli Zhan Qinghua Zhang 2021Journal of Bionic Engineering2021,18,3:3
16Phyto-Toxicity of Chromium in Maize: Oxidative Damage, Osmolyte Accumulation, Anti-Oxidative Defense and Chromium Uptake显示文摘Agricultural production systems are immensely exposed to different environmental stresses in which heavy metal stress receives serious concerns. This study was conducted to explore the deleterious effects of different chromium(Cr) stress levels, i.e., 0, 30, 6090, 120, and 150 μmol L-1, on two maize genotypes, Wandan 13 and Runnong 35. Both genotypes were evaluated by measuring their growth and yield characteristics, Cr accumulation in different plant tissues, alterations in osmolyte accumulation, generation o reactive oxygen species(ROS), and anti-oxidative enzyme activity to scavenge ROS. The results showed that Cr stress decreased the leaf area, cob formation, 100-grain weight, shoot fresh biomass, and yield formation, while Cr accumulation in different maize tissues was found in the order of roots > leaves > stem > seeds in both genotypes. The increased Cr toxicity resulted in higher free proline soluble sugars and total phenolic contents, and lower soluble protein contents. However, enhanced lipid peroxidation was noticed in the forms of malondialdehyde, hydrogen peroxide(H2O2) and thiobarbituric acid reactive substance accumulation, and electrolyte leakage. The hyperactivity of superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, especially glutathione peroxidase and glutathione reductase indicated that these anti-oxidative enzymes had a central role in protecting maize from Cr toxicity, especially for Wandan 13. Moreover, higher uptake and less translocation of Cr contents into the grains of Wandan 13 implied its importance as a potential candidate against soil Cr pollution.Shakeel Ahmad ANJUM Umair ASHRAF Imran KHAN Mohsin TANVEER Muhammad SHAHID Abdul SHAKOOR WANG Longchang 2017Pedosphere2017,27,2:3
17Degradation of methotrexate by UV/peroxymonosulfate:Kinetics,effect of operational parameters and mechanism显示文摘Methotrexate(MTX)is one of the most consumed anti-cancer drugs in the pharmaceutical market around the world.The widespread occurrence of MTX in aquatic environment through hospital effluent has attracted increasing concern due to its potential to induce water pollution.In the present study,the degradation of MTX in aqueous medium was investigated by UV-activated peroxymonosulfate(PMS).A significant improvement in degradation rate by increasing UV intensity and PMS concentration while the decrease in degradation efficiency with the increase of solution p H and initial concentration of MTX was observed.The proposed UV/PMS process could achieve more than 90%MTX degradation in 30 min with a good mineralization degree(65%).A pseudofirst order kinetic model was employed and successfully predicted the degradation of MTX.The effect of other operational parameters such as the initial concentration of the targeted compound,dosage of oxidant(PMS),solution p H and UV intensity on the degradation rate were investigated.At the last,the main transform intermediates were identified using LC–MS and possible degradation pathways were proposed.The results show that UV/PMS can be used as an efficient technology to treat pharmaceuticals such as methotrexate containing water and wastewater.Muhammad Imran Kanjal Majid Muneer Amal Abdelhaleem Wei Chu 2020Chinese Journal of Chemical Engineering2020,28,10:3
18Molecular dynamics study of the mechanical characteristics of Ni/Cu bilayer using nanoindentation显示文摘In the present work,a three-dimensional molecular dynamics simulation is carried out to perform the nanoindentation experiment on Ni single crystal.The substrate indenter system is modeled using hybrid interatomic potentials including the many-body potential embedded atom method(EAM),and two-body morse potential.To simulate the indentation process,a spherical indenter(diameter = 80 A,1 A=0.1 nm) is chosen.The results show that the mechanical behaviour of a monolithic Ni is not affected by crystalline orientation.To elucidate the effect of a heterogeneous interface, three bilayer interface systems are constructed,namely Ni(100)/Cu(111),Ni(110)/Cu(111),and Ni(111)/Cu(111).The simulations along these systems clearly describe that mechanical behaviour directly depends on the lattice mismatch. The interface with the smaller mismatch between the specified crystal planes is proved to be harder and vice versa.To describe the relationship between film thickness and interface effect,we choose various values of film thickness ranging from 20 A to 50 A to perform the nanoindentation experiment.It is observed that the interface is significant only for the relatively small thickness of film and the separation between interface and the indenter tip.It is shown that with the increase in film thickness,the mechanical behaviour of the film shifts more toward that of monolithic material.Muhammad Imran Fayyaz Hussain Muhammad Rashid S.A.Ahmad 2012Chinese Physics B2012,21,12:3
19Estimating the basic reproduction number for single-strain dengue fever epidemics显示文摘Background:Dengue,an infectious tropical disease,has recently emerged as one of the most important mosquito-borne viral diseases in the world.We perform a retrospective analysis of the 2011 dengue fever epidemic in Pakistan in order to assess the transmissibility of the disease.We obtain estimates of the basic reproduction number R0 from epidemic data using different methodologies applied to different epidemic models in order to evaluate the robustness of our estimate.Results:We first estimate model parameters by fitting a deterministic ODE vector-host model for the transmission dynamics of single-strain dengue to the epidemic data,using both a basic ordinary least squares(OLS)as well as a generalized least squares(GLS)scheme.Moreover,we perform the same analysis for a direct-transmission ODE model,thereby allowing us to compare our results across different models.In addition,we formulate a direct-transmission stochastic model for the transmission dynamics of dengue and obtain parameter estimates for the stochastic model using Markov chain Monte Carlo(MCMC)methods.In each of the cases we have considered,the estimate for the basic reproduction number R0 is initially greater than unity leading to an epidemic outbreak.However,control measures implemented several weeks after the initial outbreak successfully reduce R0 to less than unity,thus resulting in disease elimination.Furthermore,it is observed that there is strong agreement in our estimates for the pre-control value of R0,both across different methodologies as well across different models.However,there are also significant differences between our estimates for the post-control value of the basic reproduction number across the two different models.Conclusion:In conclusion,we have obtained robust estimates for the value of the basic reproduction number R0 associated with the 2011 dengue fever epidemic before the implementation of public health control measures.Furthermore,we have shown that there is close agreement between our estimates for the post-control value of R0 across the different methodologies.Nevertheless,there are also significant differences between the estimates for the post-control value of R0 across the two different models.Adnan Khan Muhammad Hassan Mudassar Imran 2014Infectious Diseases of Poverty2014,3,1:3
20Mutagenic and cytotoxic potential of Endosulfan and Lambda-cyhalothrin—In vitro study describing individual and combined effects of pesticides显示文摘Excessive use of pesticides poses increased risks to non target species including humans. In the developing countries, lack of proper awareness about the toxic potential of pesticides makes the farmer more vulnerable to pesticide linked toxicities, which could lead to diverse pathological conditions. The toxic potential of a pesticide could be determined by their ability to induce genetic mutations and cytotoxicity. Hence, determination of genetic mutation and cytotoxicity of each pesticide is unavoidable to legislate health and safety appraisal about pesticides. The objective of current investigation was to determine the genotoxic and cytotoxic potential of Endosulfan(EN) and Lambda-cyhalothrin(LC); individually and in combination. 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide(MTT) assay was utilized to determine cytotoxicity, while two mutant histidine dependent Salmonella strains(TA98, TA100) were used to determine the mutagenicity of EN and LC.Moreover, mutagenicity assay was conducted with and without S9 to evaluate the effects of metabolic activation on mutagenicity. Even though a dose dependent increase in the number of revertant colonies was detected with EN against both bacterial strains, a highly significant(p < 0.05) increase in the mutagenicity was detected in TA98 with S9. In comparison, data obtained from LC revealed less mutagenic potential than EN. Surprisingly,the non-mutagenic individual-concentrations of EN and LC showed dose dependent mutagenicity when combined. Combination of EN and LC synergistically induced mutagenicity both in TA98 and TA100. MTT assay spotlighted comparable dose dependent cytotoxicity effects of both pesticides. Interestingly, the combination of EN and LC produced increased reversion and cytotoxicity at lower doses as compared to each pesticide, concluding that pesticide exposure even at sub-lethal doses can produce cytotoxicity and genetic mutations, which could lead to carcinogenicity.Umber Saleem Sohail Ejaz Muhammad Ashraf Muhammad Ovais Omer Imran Iltaf Zainab Batool Riffat Fatima Msbah Afzal 2014Journal of Environmental Sciences2014,26,7:3
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