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Signaling mechanisms mediated by G-protein coupled receptors in human platelets

Acta Pharmacologica Sinica 2004年第7期25卷 41-46页

作者： Sheikh Arshad SAEED,Huma RASHEED,Faisal A Wahed FECTO,Mohammad Ilyas ACHAKZAI,Rahmat ALI,John Dennis CONNOR,Anwar-ul-Hassan GILANI Department of Biological and Biomedical Sciences TheAga Khan university karachi-74800 Pakistan Department of Biological and Biomedical Sciences TheAga Khan university karachi-74800 Pakistan Department of Biological and Biomedical Sciences TheAga Khan university karachi-74800 Pakistan Department of Biological and Biomedical Sciences TheAga Khan university karachi-74800 Pakistan Department of Biological and Biomedical Sciences TheAga Khan university karachi-74800 Pakistan Department of Biological and Biomedical Sciences TheAga Khan university karachi-74800 Pakistan Department of Biological and Biomedical Sciences TheAga Khan university karachi-74800 Pakistan

AIM: The present study deals with the investigation of mechanisms involved in the synergistic interaction between epinephrine and arachidonic acid (AA). METHODS: Venous blood was taken from healthy human volunteers reported to be free of medications for one week. Platelet aggregation was monitored at 37oC using Dual-channel Lumi-aggregometer. The resulting aggregation was recorded for 5 min by the measurement of light transmission as a function of time. RESULTS: The data show that a synergism in platelet aggregation mediated by subthreshold concentrations of epinephrine (1 μmol/L) and AA (0.2 μmol/L) was inhibited by the α2-receptor antagonist (yohimbine, IC50=0.6 μmol/L) and an inhibitor of AA-cyclooxygenase (COX), indomethacin (IC50=0.25 μmol/L). In examining receptor influence on intraplatelet signalling pathways, it was found that the synergistic effect was inhibited by calcium channel blockers, verapamil (IC50=0.4 μmol/L) and diltiazem (IC50=2.5 μmol/L), as well as by low concentrations of inhibitors of phospholipase C (PLC) (U73122; IC50=0.2 μmol/L) and mitogens activated protein kinase (MAPK) (PD 98059; IC50=3.8 μmol/L). Herbimycin A, a specific inhibitor of tyrosine light chain kinase (TLCK), showed inhibition at IC50 value of 15 μmol/L, whereas chelerythrine, a protein kinase C (PKC) inhibitor, had no effect up to 20 μmol/L. CONCLUSION: These data suggest that synergism between epinephrine and AA in platelet aggregation is triggered through receptors coupled to G-protein, which in turn, activate PLC, COX, and MAP kinase-signaling pathways.

关键词： platelet aggregation epinephrine arachidonic acid cyclooxygenase phospholipase C calcium channel blockers nitric oxide MAP kinase

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Homotopy perturbation aided optimization procedure with applications to oscillatory fractional order nonlinear dynamical systems

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International Journal of Modeling, Simulation, and Scientific Computing 2019年第4期10卷 107-128页

作者： Najeeb Alam Khan Tooba Hameed Samreen Ahmed Department of Mathematics University of KarachiKarachi 75270Pakistan

This paper presents an approximate solution of nonlinear fractional differential equations(FDEs)that exhibit an oscillatory behavior by using a metaheuristic *** solutions of the governing equations are approximated by using homotopy perturbation method(HPM)along with the fractional derivative in the Caputo *** designed methodology is based on a weighted series of HPM in conjunction with a nature-inspired *** idea is instantly fascinated by the researchers on the consequent implementation of nature-inspired learning algorithms such as a Cuckoo search algorithm(CSA).The usage of CSA has accelerated the minimized search path of error to the convergent values of the *** validity and accuracy of the proposed technique are ascertained by calculating the approximate solution and the error norms which ensure the convergence of the approximation that can be further *** critical analysis is also provided by the numerical simulation of two different test *** of key points has been determined by the tabulation of numerical values and *** study of the results with known numerical technique is also performed.

关键词： Lotka-Volterra model Brusselator model Caputo fractional derivative Cuckoo search algorithm

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Monitoring the diversity of malaria and dengue vector in karachi:studying variation of genera and subgenera of mosquitoes under different ecological conditions

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Ecological Processes 2014年第1期3卷 116-124页

作者： Saima Shaikh Syed Jamil H Kazmi Salman Qureshi Department of Geography University of KarachiKarachi 75270Pakistan Department of Geography(Landscape Ecology) Humboldt University of BerlinRudower Chaussee 16Berlin 12489Germany School of Architecture Birmingham City UniversityThe Parkside Building5 Cardigan StreetBirmingham B47BDUK

Introduction:karachi,a city of unique terrain and moderate tropical climate,is home to several mosquito *** geographical distribution and density of these species may vary within the city,owing to their interaction with an ever-increasing population and urban *** a consequence,the prevalence of vector-borne diseases is unpredictable within the geographical limits of karachi *** this spatiotemporal study,1,156 mosquito samples were collected from 50 study sites with unique ecological characteristics within the city and a taxonomical exercise was conducted to investigate different vector species thriving in different months and seasons of the *** main genera of mosquitoes were identified and categorized using a pictorial key based on the standard guidelines of the Walter Reed Biosystematics Unit,substantiated with ancillary ***:Three important genera were found in karachi:Anopheles,Aedes and *** subgenera were subsequently identified,based on their susceptibility to major vector-borne *** had the highest concentration of adult mosquitoes,as the colder weather conditions were suitable for *** recorded the lowest number,owing to excessively hot weather when most of the breeding pockets had dried out;less vegetation(in pre-monsoon conditions)prevented mosquito ***:Slum areas showed an abundance of malaria and dengue vectors,owing to poor hygiene conditions caused by open sewage ***,a major precaution is to raise awareness among people about mosquito-borne *** breeding habitats of these vectors should be studied using geospatial technologies to improve spatial and temporal coverage.

关键词： landscape ecology mosquito species spatial epidemiology spatial variation urban ecology urban habitat vector-borne diseases

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Synthesized graphene oxide and fumed aerosil 380 dispersion stability and characterization with partially hydrolyzed polyacrylamide

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Chinese Journal of Chemical Engineering 2021年第6期34卷 307-322页

作者： Najeebullah Lashari Tarek Ganat Department of Petroleum Engineering Universiti Teknologi PETRONAS32610 Seri IskandarPerak Darul RidzuanMalaysia Department of Petroleum and Gas Engineering Dawood University of Engineering&TechnologyM.A Jinnah RoadKarachi 74800Pakistan

Hydrolyzed polyacrylamide(HPAM)is a commonly used polymer for the chemicals,mining and refining processes of hydrocarbon but suffers from a persistent high-temperature instability *** contrast,the nanoparticle suspension remains a technical challenge because of the strong interactions of van der Waal forces within nanoparticles,which always encourage *** research sought to improve nanoparticles(NP)stability and polymer(HPAM)rheological properties to improved hydrocarbon recovery by utilizing synthesized graphene oxide(GO)nanosheets and fumed Aerosil 380 Silica oxide(SiO_(2)).The aqueous nanocomposites based on HPAM-GO and HPAM-SiO_(2) in aqueous polymeric solutions have been developed,and its viscoelastic and static behaviour is *** results imply that by adding fumed silica NP,the viscoelastic behaviour of HPAM is marginally improved,particularly in high temperatures and salinity,however,the inclusion of GO's significantly improves the viscosity and stability of the base polymer fluid at high *** Fourier data for the transformation of the infrared spectrum confirmed that the hydrogen bonding formed between HPAM carbonyl groups and silica NP surface silanol functionality and covalent interlinking of electrostatic h-bonding between HPAM and functional GO contributed to the improved stabilization and improved rheological performance that helps to recover high salinity and temperature hydrocarbons.

关键词： Aggregation Composites Chemical enhance oil recovery Hydrocarbons Nanoparticles Polymer

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Weathering and accumulation of trace elements in the soils of the Porali Plain, Balochistan: repercussions in agriculture

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Acta Geochimica 2024年第2期43卷 214-234页

作者： Maria Kaleem Erum Bashir Shahid Naseem Tahir Rafique Bushra Shahab Department of Geology University of KarachiKarachi 75270Pakistan Applied Chemistry Research Centre PCSIR Laboratories ComplexKarachi 75280Pakistan

This study is theﬁrst attempt to assess the nature of the soil,especially on the western side of the Porali Plain in Balochistan;a new emerging agriculture hub,using weathering and pollution indices supplemented by multi-variate analysis based on geochemical *** outcomes of this study are expected to help farmers in soil manage-ment and selecting suitable crops for the ***-ﬁve soil samples were collected,mainly from the arable land of the Porali *** drying and coning-quarter-ing,soil samples were analyzed for major and trace ele-ments using the XRF technique;sieving and hydrometric methods were employed for granulometric ***-mated data were analyzed using Excel,SPSS,and Surfer software to calculate various indices,correlation matrix,and spatial *** granulometric analysis showed that 76%of the samples belonged to loam types of soil,12%to sand type,and 8%to silt *** indices:CIA,CIW,PIA,PWI,WIP,CIX,and ICV were calculated to infer the level of *** indices reﬂect mod-erate to intense weathering;supported by K_(2)O/AI_(2)O_(3),Rb/K_(2)O,Rb/Ti,and Rb/Sr *** of the geo-ac-cumulation and Nemerow Pollution indices pinpoint rela-tively high concentrations of Pb,Ni,and Cr concentration in the *** correlation matrix and Principal Compo-nent Analysis show that the soil in this study area is mainly derived from the weathering of igneous rocks of Bela Ophiolite(Cretaceous age)and Jurassic sedimentary rocks of Mor Range having SEDEX/MVT type *** may result in the undesirable accumulation of certain trace elements which adversely affects crops.

关键词： Weathering indices Pollution indices Accumulation Repercussions Trace elements Multivariate analyses Porali Plain Balochistan

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Sustainable bio-energy generation via the conversion of spent wash using dual chamber microbial fuel cell

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Waste Disposal and Sustainable Energy 2024年第2期6卷 219-231页

作者： Abdul Sattar Jatoi Jawad Ahmed Afaque Ahmed Bhutto Muhammad Shuaib Shaikh Department of Chemical Engineering Dawood University of Engineering and Technology KarachiSindhPakistan Changzhou DUBO Polymer Co. Ltd.Changzhou 213002China Department of Basic Science and Related Studies The University of LarkanoSindhPakistan Department of Chemical Engineering Mehran University of Engineering and Technology JamshoroSindhPakistan

Microbial fuel cells(MFCs)are innovative devices that combine microbial processes with electrochemical reactions to convert organic matter in wastewater into electricity while simultaneously treating the *** such application is the treatment of spent wash,a highly polluting effluent generated from the distillery industry after crude mesh is separated into ethanol and spent *** wash,also known as distillery effluent or stillage,is a highly challenging wastewater treatment method due to its high chemical oxygen demand(COD),biological oxygen demand(BOD),and total dissolved solids(TDS).These characteristics make it a complex and polluting industrial effluent that requires specialized treatment processes to reduce its environmental impact ***,MFCs have shown promise in treating spent wash,as they can utilize the organic matter in wastewater as a fuel source for microbial growth as well as for electricity *** the treatment of spent wash,Saccharomyces cerevisiae *** used as a biocatalyst along with 340 mol/L potassium ferricyanide in the cathode chamber and 170 mol/L methylene blue in the anode as a *** tests were conducted by balancing a one-liter volume for power production from spent wash in MFC with the optimal conditions of 10%agarose,pH 8.5,300 mL/min of aeration in the cathode chamber,and 40%(in weight)substrate *** an ideal concentration,the maximum current and power density are roughly 53.41 mA/m^(2)and 72.22 mW/m^(2),*** each litre of processed spent wash,a maximum voltage of 850 mV(4.5 mA)was ***,91%of COD and BOD were removed from the effluent *** findings show that MFCs are capable of producing electricity and efficiently removing COD from wasted wash at the same time.

关键词： Microbial fuel cell Chemical oxygen demand Biological oxygen demand-Current density Power density Spent wash

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Invariant of Enhanced AES Algorithm Implementations Against Power Analysis Attacks

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Computers, Materials & Continua 2022年第7期72卷 1861-1875页

作者： Nadia Mustaqim Ansari Rashid Hussain Sheeraz Arif Syed Sajjad Hussain Department of Electronic Engineering Dawood University of Engineering&TechnologyKarachiPakistan Faculty of Engineering Sciences and Technology Hamdard UniversityKarachiPakistan Faculty of Information Technology Salim Habib UniversityKarachiPakistan Faculty of Computer Sciences SZABISTKarachiPakistan

The security of Internet of Things(IoT)is a challenging task for researchers due to plethora of IoT *** Channel Attacks(SCA)are one of the major *** prime objective of SCA is to acquire the information by observing the power consumption,electromagnetic(EM)field,timing analysis,and acoustics of the ***,the attackers perform statistical functions to recover the *** Encryption Standard(AES)algorithm has proved to be a good security solution for constrained IoT *** paper implements a simulation model which is used to modify theAES algorithm using logicalmasking *** invariant of the AES algorithm hides the array of bits during substitution byte transformation of *** model is used against SCAand particularly Power Analysis Attacks(PAAs).Simulation model is designed on MATLAB *** will give better solution by hiding power profiles of the IoT devices against *** future,the lightweight AES algorithm with false key mechanisms and power reduction techniques such as wave dynamic differential logic(WDDL)will be used to safeguard IoT devices against side channel attacks by using Arduino and field programmable gate array(FPGA).

关键词： Side channel attacks power analysis attacks network security masking advance encryption standard

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Characteristic spectral studies and in vitro antifungal activity of some Schiff bases and their organotin (Ⅳ) complexes

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Chinese Science Bulletin 2004年第2期49卷 119-122页

作者： Wajid Rehman Musa Kaleem Baloch Bakhtiar Muhammad Amin Badshah Khalid M.Khan Department of Chemistry Gomal university Dera Ismail KhanPaki-stanDepartment of Chemistry Gomal UniversityDera Ismail KhanPaki-stanDepartment of Chemistry Gomal UniversityDera Ismail KhanPaki-stanDepartment of ChemistryQuaid-e-Azam UniversityIslamabadPaki-stanHEJ Research Institute University of KarachiPakistan

The synthesis and in vitro antifungal activity of some Schiff bases and their Sn (Ⅳ) complexes has been tested against plant pathogenic fungi and it is found that they possess excellent fungicidal activity. On the basis of ^1H-, ^13C-,^119Sn NMR-, ^119Sn Mǒssbauer, IR and Elemental analysis the tetrahedral geometry is proposed for the synthesized compounds.

关键词：特征光谱抗真菌活性有机锡有机金属化合物

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Data Analysis of Network Parameters for Secure Implementations of SDN-Based Firewall

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Computers, Materials & Continua 2023年第11期77卷 1575-1598页

作者： Rizwan Iqbal Rashid Hussain Sheeraz Arif Nadia Mustaqim Ansari Tayyab Ahmed Shaikh Department of Telecommunication Engineering Dawood University of Engineering&TechnologyKarachiPakistan Faculty of Engineering Sciences and Technology Hamdard UniversityKarachiPakistan Faculty of Information Technology Salim Habib UniversityKarachiPakistan Department of Electronic Engineering Dawood University of Engineering&TechnologyKarachiPakistan

Software-Defined Networking(SDN)is a new network technology that uses programming to complement the data plane with a control *** enable safe connection,however,numerous security challenges must be *** attacks have been one of the most prominent risks on the internet for decades,and they are now becoming challenging difficulties in SDN *** solve these challenges,we proposed a unique firewall application built on multiple levels of packet filtering to provide a flooding attack prevention system and a layer-based packet detection *** study offers a systematic strategy for wrapping up the examination of SDN *** Mininet simulator examines the effectiveness of SDN-based firewalls at various network *** fundamental network characteristics that specify how SDN should *** three main analytical measures of the network are jitter,response time,and *** regular operations,their behavior evaluates in the standard SDN conditions of Transmission Control Protocol(TCP)flooding and User Datagram Protocol(UDP)flooding with no SDN *** Orbit Ion Cannon(LOIC)is applied to launch attacks on the transmission by the allocated *** and MATLAB are used for the behavioral study to determine how sensitive the parameters are used in the SDN network and monitor the fluctuations of those parameters for different simulated scenarios.

关键词： Software defined networking firewall POX controller open v switch Mininet OpenFlow

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A facile synthesis of novel unsymmetrical N-(4-oxo-2-phenyl-3(4H)-quinazolinoyl)-N-(aryl) acetamidines

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Chinese Chemical Letters 2010年第8期21卷 905-910页

作者： Rasool Khan Mohammad Arfan Javeed Mahmood Shazia Anjum M.Iqbal Choudhary Department of Chemistry Abdul Wali Khan UniversityMardan-23200NWFPPakistan Institute of Chemical Sciences University of PeshawarPeshawar-25120Pakistan university of Saskatchewan Department of ChemistrySaskatoon S7N5C9Canada HEJRIC International Center for Chemical and Biological SciencesUniversity of KarachiKarachi-75270Pakistan

A series of novel unsymmetrical N-（4-oxo-2-phenyl-3（4H）-quinazolinoyl）-N-（aryl） acetamidines was synthesized by reacting ethyl（1H）-N-（4-oxo-2-phenylquinazolin-3（4H）-y1）ethanimidoate（2） and suitable reactive aromatic ***＇ determination of the synthesized compounds was carried out using spectroscopic techniques including IR,~1H NMR,and mass spectrometry. Structural effects on reactivity were also studied.

关键词： 3-Amino-2-phenyl-4(3H)-quinazolinone Triethylorthoacetate Unsymmetrical N-(4-oxo-2-phenyl-3(4H)-quinazolinoyl)-N-(aryl) acetamidines

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