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molecular Plant 2013年第3期6卷 592-595页

作者： Jieun Shin muhammad usman Anwer Seth Jon Davis max Planck Institute for Plant Breeding Research 50829 Cologne Germany Department of Biology University of York York UK

The rotation of the Earth around its axis results in distinct changes in light and temperature during a 24-h day/ night cycle. Plants being sessile are constantly and predictably exposed to these environmental changes. It is therefore critical for them to properly perceive environmental signals in order to effectively manage growth and development.

关键词： Phytochrome-Interacting Factors (PIFs) Regulation

Structural and optical properties of thermally reduced graphene oxide for energy devices

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Chinese Physics B 2017年第8期26卷 346-352页

作者： Ayesha Jamil Faiza mustafa Samia Aslam.usman Arshad muhammad Ashfaq Ahmad Department of Physics COMSATS Institute of Information TechnologyLahore 54000Pakistan

Natural intercalation of the graphite oxide, obtained as a product of Hummer＇s method, via ultra-sonication of water dispersed graphite oxide has been carried out to obtain graphene oxide（GO） and thermally reduced graphene oxide（RGO）.Here we report the effect of metallic nitrate on the oxidation properties of graphite and then formation of metallic oxide（mO） composites with GO and RGO for the first time. We observed a change in the efficiency of the oxidation process as we replaced the conventionally used sodium nitrate with that of nickel nitrate Ni（NO_3）_2, cadmium nitrate Cd（NO_3）_2,and zinc nitrate Zn（NO_3）_2. The structural properties were investigated by x-ray diffraction and observed the successful formation of composite of mO–GO and mO–RGO（m = Zn, Cd, Ni）. We sought to study the effect on the oxidation process through optical characterization via UV-Vis spectroscopy and Fourier Transform Infrared（FTIR） ***, Thermo Gravimetric Analysis（TGA） was carried out to confirm 〉 90% weight loss in each process thus proving the reliability of the oxidation cycles. We have found that the nature of the oxidation process of graphite powder and its optical and electrochemical characteristics can be tuned by replacing the sodium nitrate（NaNO_3） by other metallic nitrates as Cd（NO_3）_2, Ni（NO_3）_2, and Zn（NO_3）_2. On the basis of obtained results, the synthesized GO and RGO may be expected as a promising material in antibacterial activity and in electrodes fabrication for energy devices such as solar cell, fuel cell,and super capacitors.

关键词： thermal properties of graphene oxide and reduced graphene oxide optical properties structuralproperties fuel cell composite materials

Land use/land cover classification and its change detection using multi-temporal mODIS NDVI data

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Journal of Geographical Sciences 2015年第12期25卷 1479-1506页

作者： m.usman R LIEDLI m A SHAHID A ABBAS Institute for Groundwater management TU Dresden 01069 Dresden Germany University of Agriculture Faisalabad Pakistan Leibniz Centre for Agricultural Landscape Research (ZALF) Eberswalder Str. 84 15374 Mencheberg Germany

Detailed analysis of Land Use/Land Cover （LULC） using remote sensing data in complex irrigated basins provides complete profile for better water resource management and planning. Using remote sensing data, this study provides detailed land use maps of the Lower Chenab Canal irrigated region of Pakistan from 2005 to 2012 for LULC change detection. major crop types are demarcated by identifying temporal profiles of NDVI using mODIS 250 m × 250 m spatial resolution data. Wheat and rice are found to be major crops in rabi and kharif seasons, respectively. Accuracy assessment of prepared maps is performed using three dif- ferent techniques： error matrix approach, comparison with ancillary data and with previous study. Producer and user accuracies for each class are calculated along with kappa coeffi- cients （K）. The average overall accuracies for rabi and kharif are 82.83% and 78.21%, re- spectively. Producer and user accuracies for individual class range respectively between 72.5% to 77% and 70.1% to 84.3% for rabi and 76.6% to 90.2% and 72% to 84.7% for kharif. The K values range between 0.66 to 0.77 for rabi with average of 0.73, and from 0.69 to 0.74 with average of 0.71 for kharif. LULC change detection indicates that wheat and rice have less volatility of change in comparison with both rabi and kharif fodders. Transformation be- tween cotton and rice is less common due to their completely different cropping conditions. Results of spatial and temporal LULC distributions and their seasonal variations provide useful insights for establishing realistic LULC scenarios for hydrological studies.

关键词： land use/land cover remote sensing normalized difference vegetation index accuracy assessment change detection hydrological modeling

Discovery of human coronaviruses pan-papain-like protease inhibitors using computational approaches

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Journal of Pharmaceutical Analysis 2020年第6期10卷 546-559页

作者： mubarak A.Alamri muhammad Tahir ul Qamar muhammad usman mirza Safar m.Alqahtani matheus Froeyen Ling-Ling Chen Department of Pharmaceutical Chemistry College of PharmacyPrince Sattam Bin Abdulaziz UniversityAlkarjSaudi Arabia College of Life Science and Technology Guangxi UniversityNanningChina Department of Pharmaceutical and Pharmacological Sciences Rega Institute for Medical ResearchMedicinal ChemistryUniversity of LeuvenB-3000LeuvenBelgium Hubei Key Laboratory of Agricultural Bioinformatics College of InformaticsHuazhong Agricultural UniversityWuhan430070China

The papain-like protease(PLpro)is vital for the replication of coronaviruses(Co Vs),as well as for escaping innate-immune responses of the ***,it has emerged as an attractive antiviral *** this study,computational approaches were employed,mainly the structure-based virtual screening coupled with all-atom molecular dynamics(mD)simulations to computationally identify specific inhibitors of severe acute respiratory syndrome coronavirus 2(SARS-Co V-2)PLpro,which can be further developed as potential pan-PLprobased broad-spectrum antiviral *** sequence,structure,and functional conserveness of most deadly human Co Vs PLprowere explored,and it was revealed that functionally important catalytic triad residues are well conserved among SARS-Co V,SARS-Co V-2,and middle east respiratory syndrome coronavirus(mERS-Co V).The subsequent screening of a focused protease inhibitors database composed of^7,000 compounds resulted in the identification of three candidate compounds,ADm13083841,LmG15521745,and *** three compounds established conserved interactions which were further explored through mD simulations,free energy calculations,and residual energy contribution estimated by mm-PB(GB)SA *** these compounds showed stable conformation and interacted well with the active residues of SARS-Co V-2 PLpro,and showed consistent interaction profile with SARS-Co V PLproand mERS-Co V PLproas ***,the reported SARS-Co V-2 PLprospecific compounds could serve as seeds for developing potent pan-PLprobased broad-spectrum antiviral drugs against deadly human ***,the presented information related to binding site residual energy contribution could lead to further optimization of these compounds.

关键词： COVID-19 mERS-CoV molecular dynamic simulation Pan-inhibitors Papain-like protease SARS-CoV SARS-CoV-2 Virtual screening

Geoelectrical Investigation of Groundwater Potentials of Northern Paiko,Niger State,North Central Nigeria

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Journal of Earth Science 2017年第1期28卷 103-112页

作者： usman D.Alhassan Daniel Nnaemeka Obiora Francisca Nneka Okeke Department of Physics Federal University of Technology Department of Physics and Astronomy University of Nigeria

Vertical electrical sounding（VES） was carried out in northern part of Paiko, North Central Nigeria, using Abem terrameter model SAS 4000 to determine the subsurface layer parameters（resistivities, depths and thickness） employed in delineating the groundwater potential of the area. A total of six transverses with ten VES stations along each traverse, at intervals of 50 m were investigated. It has a maximum current electrode separation（AB/2） of 100 m. Three to four distinct geoelectric layers were observed, namely, the top layer, the weathered layer, the fractured/fresh layer, and the fresh basement layer. The observed frequencies in curve types include 21% of H, 4.2% of HA, 2.4% of K, 4.2% of A, 1.67% of KH and 3% of HK. Eight VES stations were delineated as ground water potentials of the area, with third and fourth layer resistivities ranging from 191 to 398 ？·m. Depths range from 13.60 to 36.60 m and thickness varies from 9.23 to 30.51 m. A correlation of the borehole log with the VES lithology is in agreement. Viable boreholes for good portable water should be sited at VES stations J8 and J10 having a fine aquifer at a depth of 36.60 and 17.80 m respectively with thickness of 30.51 and 15.07 m, respectively.

关键词： vertical electrical sounding groundwater potential northern Paiko resistivity aquifer,geoelectric layer Abem terrameter.

Humidity Effect on Transport Properties of Titanium Dioxide Nanoparticles

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Journal of materials Science & Technology 2014年第8期30卷 748-752页

作者： muhammad usman Kamran Rasool S. S. Batool Z. Imran mushtaq Ahmad Hira Jamil m. A. Rafiq m. m. Hasan micro and Nano Devices Group Department of Metallurgy and Materials Engineering(DMME)Pakistan Institute of Engineering and Applied Sciences(PIEAS)P. O. NiloreIslamabad 45650Pakistan

Rutile TiO2 nanoparticles were synthesized using co-precipitation method with an average diameter of 30 nm TiO2 nanoparticle device was then fabricated on glass *** electrodes were defined using photolithography and vacuum evaporation.A suspension of TiO2 nanoparticles was prepared in isopropanol using ultrasonic *** nanoparticles were deposited between the *** device was tested by AC electrical measurements at 40%-90%relative humidity（RH）.The impedance of the TiO2nanoparticles decreases by about 80 times with the increase in RH from 40%to 90%at 100 *** response time and the recovery time were 4 s and 5 s,respectively between 40%and 90%*** 100 Hz,the sensitivity of the aluminum electrode TiO2 nanoparticle device in the range of 40%—90%RH was17 mΩ/%*** modulus analysis also confirms the increase in DC conductivity of TiO2 nanoparticles as RH increases.

关键词： TiO2 nanoparticles Co-precipitation Transport properties

Ultrahydrophobic melamine sponge via interfacial modification with reduced graphene oxide/titanium dioxide nanocomposite and polydimethylsiloxane for oily wastewater treatment

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Water Science and Engineering 2024年第2期17卷 139-149页

作者： Hamidatu Alhassan Ying Woan Soon Anwar usman Voo Nyuk Yoong Department of Physics Universiti Brunei DarussalamBandar Seri Begawan BE1410Brunei Department of Chemical Sciences Universiti Brunei DarussalamBandar Seri Begawan BE1410Brunei

Three-dimensional(3D)porous absorbents have attracted significant attention in the oily wastewater treatment technology due to their high porosity and *** their amphiphilic surface,they have a propensity to simultaneously absorb water and oil,which restricts their range of *** this study,a reduced graphene oxide and titanium dioxide nanocomposite(rGO/TiO_(2))was used to fabricate an ultra-hydrophobic melamine sponge(mS)through interfacial modification using a solution immersion *** further modify it,poly-dimethylsiloxane(PDmS)was grafted onto its surface to establish stronger covalent bonds with the *** water contact angle of the sponge(rGO/TiO_(2)/PDmS/mS)was 164.2°,which satisfies the condition for *** evidence of its water repellency was demonstrated by the Cassie-Baxter theory and the lotus leaf *** a result of the increased density of rGO/TiO_(2)/PDmS/mS,it recorded an initial capacity that was 2 g/g lower than the raw mS for crude oil *** raw mS retained 53% of its initial absorption capacity after 20 cycles of absorption,while rGO/TiO_(2)/PDmS/mS retained 97%,suggesting good *** oil and organic solvent recovery(90%-96%)was demonstrated by rGO/TiO_(2)/PDmS/mS in oil-water *** a continuous separation system,it achieved a remarkable separation efficiency of 2.4×10^(6)L/(m^(3)·h),and in turbulent emulsion separation,it achieved a demulsification efficiency of 90%-91%.This study provides a practical substitute for massive oil spill cleaning.

关键词： Oily wastewater Reduced graphene oxide Polydimethylsiloxane(PDmS) Emulsion separation melamine sponge

12-Tungstophosphoric acid niched in Zr-based metal-organic framework:a stable and efficient catalyst for Friedel-Crafts acylation

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Science China Chemistry 2018年第4期61卷 402-411页

作者： Latif Ullah Guoying Zhao Zichen Xu Hongyan He muhammad usman Suojiang Zhang Beijing Key Laboratory of Ionic Liquids Clean Process Key Laboratory of Green Process EngineeringState Key Laboratory of Multiphase Complex SystemsInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Center of Excellence in Nanotechnology King Fahd University of Petroleum and MineralsDhahran 3126Saudi Arabia

Heteropoly acids(HPA) are well known for their versatile solid acid catalysis in diverse chemical reactions, however they suffer from low surface area(<10 m^2/g) and leaching into the reactions media, which reduce the... 详细信息

Heteropoly acids(HPA) are well known for their versatile solid acid catalysis in diverse chemical reactions, however they suffer from low surface area(m^2/g) and leaching into the reactions media, which reduce their prospects as industrial ***, a novel hybrid material HPW@Zr-BTC,composed of 12-tungstophoric acid(HPW) and Zr^(Ⅳ)-benzene tri-carboxylate(Zr-BTC) metal-organic framework(mOF), was prepared via one-pot solvothermal method. Excellent HPW loading up to 32.3 wt% was achieved, and HPW@Zr-BTC composite proved to be highly stable, besides the crystalline morphology of Zr-BTC was intact. The catalytic activity of the hybrid composite was explored via Friedel-Crafts acylation of anisole with benzoyl *** 28.2 wt% HPW@Zr-BTC showed excellent catalytic performance, with 99.4% anisole conversion and 97.6% yield(pmethoxybenzophenone) under solvent free conditions. Excellent retention of catalytic activity was achieved after at least five consecutive runs due to non-observable HPW leaching. The promising activity and stability of the catalyst forecasted its potential industrial applications.

关键词： dodeca-tungstophosphoric acid Zr-BTC metal-organic frameworks one-pot solvothermal synthesis heterogeneouscatalysis anisole acylation high temperature XRD

Unfolding the structural features of NASICON materials for sodium-ion full cells

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Carbon Energy 2022年第5期4卷 776-819页

作者： muhammad Tayyab Ahsan Zeeshan Ali muhammad usman Yanglong Hou School of materials Science and Engineering Peking UniversityBeijingChina School of Chemical and materials Engineering National University of Sciences and Technology(NUST)IslamabadPakistan Beijing Key Laboratory for magnetoelectric materials and Devices(BKL-mmD) School of Materials Science and EngineeringPeking UniversityBeijingChina

Sodium-ion batteries(SIBs)are potential candidates for the replacement of lithium-ion batteries to meet the increasing demands of electrical storage systems due to the low cost and high abundance of *** superionic conductor(NASICON)structured materials have attracted enormous interest in recent years as electrode materials for safer and long-term performance of SIBs for electric energy storage smart *** materials have a threedimensional robust framework,high redox potential,thermal stability,and a fast Na^(+)-ion diffusion ***,NASICON has low intrinsic electronic conductivity,which limits the electrochemical *** review describes the structural features of NASICONs to illustrate the ion storage mechanism and electrochemical performance of *** of the NASICON crystal structure,the affiliated Na^(+)-ion diffusion mechanism,morphology,and electrochemical performance of these materials in sodiumion half-cells as well as full cells are *** addition to the application as electrode materials,the use of NASICONs as solid electrolytes is also elaborated in solid-state *** on these aspects,we have provided more perspectives in terms of the commercialization of SIBs and strategies to overcome the limitations of ***,this review is expected to provide the researchers of energy storage with an in-depth understanding of NASICON materials with the knowledge of structural features,which will provide a new avenue on the practicality of SIBs.

关键词： cathode materials electrical storage systems full cells NASICON materials sodium-ion batteries

Corrosion behavior of mg-Zn-Zr-RE alloys under physiological environment-Impact on mechanical integrity and biocompatibility

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Journal of magnesium and Alloys 2022年第6期10卷 1542-1572页

作者： marwa AbdelGawad Chaudhry A.usman Vasanth C.Shunmugasamy Ibrahim Karaman Bilal mansoor mechanical Engineering Program Texas A&M University at QatarEducation CityDoh1Qatar Department of mechanical Engineering Texas A&M University3123 TAMUCollege StationTX 77843United States of America Department of materials Science and Engineering Texas A&M University3003 TAMUCollege StationTX 77843United States of America

Benefits of RE addition on mg alloys strength and corrosion resistance are widely reported but their effects on biodegradability and biocompatibility are still of *** paper investigates the effect of RE additions on biodegradability of mg-Zn alloys under simulated physiological *** this context,two commercial mg-Zn-Zr-RE alloys,namely ZE41 and EZ33,with same RE addition but different concentrations are studied in Hank’s Balanced Salt Solution(HBSS)at 37℃and with pH of ***-loss,hydrogen evolution,real-time insitu drop test,electrochemical impedance spectroscopy(EIS)and potentiodynamic polarization are deployed to study corrosion *** mechanical integrity of both alloys is assessed by mechanical testing post ***,in vitro biocompatibility is evaluated by indirect cytotoxicity tests using NIH3T3 *** reveal that although both alloys showed similar microstructure,size and distribution of precipitates played a significant role on its corrosion *** and open circuit potential results show stable film formation on EZ33,while ZE41 showed passive layer formation followed by its deterioration,over the analyzed time *** real-time drop test,it was shown in ZE41 alloy that both T-phase and Zr-rich precipitates acted as micro cathodes,resulting in an unstable surface *** EZ33,Zr-rich regions did not influence corrosion response,resulting in better corrosion resistance that was corroborated by post-immersion surface morphology *** higher degradation observed in ZE41 alloy resulted in higher drop in flexural and tensile strength compared to EZ33 *** addition,cytotoxicity tests on NIH3T3 cells revealed that cell viability of EZ33 increased with increasing incubation time,contrary to ZE41,owing to its lower biodegradation behavior and despite higher concentrations of *** results show that an increase in RE concentration in EZ33,relative to ZE41,had a positive effect on

关键词： magnesium alloy Corrosion EIS mechanical integrity Cytotoxicity