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First-Principles Study of Electronic Structure and Optical Properties of Cubic Perovsk.te CsCaF_(3)

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Chinese Physics Letters 2012年第11期29卷 173-177页

作者： k.ephraim babu A.Veeraiah D.Tirupati Swamy V.Veeraiah Modelling and Simulation in Materials Science Laboratory Department of PhysicsAndhra UniversityVisakhapatnamAndhra Pradesh530003India

Electronic,structural and optical properties of the cubic perovsk.te CsCaF_(3) are calculated by using the full potential linearized augmented plane wave(FP-LAPW)plus local orbitals method with generalized gradient approximation(GGA)in the framework.of the density functional *** calculated lattice constant is in good agreement with the experimental *** electronic band structure shows that the fundamental band gap is wide and indirect at(Γ–R)*** contribution of the different bands is analyzed from the total and partial density of states *** charge density plots show strong ionic bonding in Cs-F,and ionic and weak.covalent bonding between Ca and *** of the optical spectra,viz.,the dielectric function,optical reflectivity,absorption coefficient,real part of optical conductivity,refractive index,extinction coefficient and electron energy loss,are performed for the energy range 0–30 eV.

关键词： theory bonding ionic

Premature axon-oligodendrocyte interaction contributes to stalling of experimental axon regeneration after injury to the white matter

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Neural Regeneration Research 2024年第3期19卷 469-470页

作者： ephraim F.Trak.tenberg Department of Neuroscience University of Connecticut School of MedicineFarmingtonCTUSA

Studies from nearly 3 decades ago suggested that,in the central nervous system(CNS),myelination of axons by oligodendrocytes not only helps improve axonal conductivity but also stabilizes circuitry(Colello and Schwab,1994).Over the years,myelin sheaths produced by oligodendrocytes have been found to contain multiple molecules that are inhibitory to axonal growth(e.g.,MAG,NogoA,OMgp,Semaphorins)(Yiu and He,2006;Silver et al.,2014).After white matter injury in the adult CNS,myelin debris from damaged axons and dead oligodendrocytes accumulates in the forming glial scar and exposes these myelin-associated axon growth-inhibitory molecules to the injured axonal stumps,thereby contributing to the inhibition of axonal *** development,CNS axons reach their postsynaptic targets and stop growing before oligodendrocytes appear and myelinate them(Foran and Peterson,1992;Dangata et al.,1996).Therefore,myelin-associated axon growth-inhibitory molecules interacting with already grown axons during myelination were thought to block.axons from promiscuous sprouting and miswiring,thereby stabilizing neural circuitry in the CNS(Colello and Schwab,1994).

关键词： thereby white injury

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Mitigating self-excited flame pulsating and thermoacoustic oscillations using perforated liners

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Science Bulletin 2019年第13期64卷 941-952页

作者： Dan Zhao ephraim Gutmark.Arne Reineck. Department of Mechanical Engineering College of EngineeringUniversity of CanterburyChristchurch 8140New Zealand Department of Aerospace Engineering and Engineering Mechanics University of CincinnatiCincinnatiOH 45221-0070USA School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingapore 639798Singapore

Open-loop control of self-excited flame pulsating oscillations and thermo-acoustic instability is considered in this *** performance of the control strategy is numerically evaluated in a 2 D Rij k.-type combustor with a perfo rated pipe *** is found that approximately 38 dB sound pressure level(SPL)reduction can be achieved by actively tuning the cooling flow through the perforated ***,the vorticity-induced damping performance is contributing to the break.ng up of flame-acoustics ***,the shedding of vortices is not uniformly distributed along the perforated *** apply the control strategy in practice and to validate the findings,experimental studies are performed on a customerdesigned Rij k.-type combustor with a perfo rated liner *** mimic practical engines,a cooling flow generated by a centrifugal pump is provided to pass through the perforated *** tuning the cooling flow rate is found to lead to the unstable combustor being successfully *** is red uced by approximately 35 dB at ω1/2π≈245 Hz,and harmonic thermoacoustic modes are completely *** study is conducted by suddenly re moving the perforated pipe *** combustion system is found to be associated with not only classical thermo-acoustic limit cycle oscillations with a dominant mode at 2.45 × 102 Hz,but also beating oscillations at 1.4 × 1 00 *** is revealed that increasing acoustic losses by implementing the perforated pipe is another critical mechanism contributing to attenuating flame pulsating *** present work.opens up an applicable means to attenuate both selfexcited high-frequency thermoacoustic and low-frequency flame pulsating oscillations.

关键词： Flame beating Combustion instability Thermo-acoustic instability Thermal-diffusive instability Perforated pipe Acoustic losses

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Inhibition of α-glucosidase activity by N-deoxynojirimycin analogs in several insect phloem sap feeders

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Insect Science 2016年第1期23卷 59-67页

作者： Marina k.tzman Ya'k.bovitz Terry D. Butters ephraim Cohen Department of Entomology Robert H. Smith Faculty of Agriculture Food and Environment The Hebrew University of Jerusalem RehovotIsrael Department of Biochemistry University of Oxford Oxford OX1 3QU UK

Secondary metabolites and synthetic iminosugars that structurally resemble monosaccharides are potent inhibitors of a-glucosidase activity. The enzyme is core in cleaving sucrose in phloem feeding insects and it also plays a crucial role of reducing osmotic stress via the formation of oligosaccharides. Inhibition of hydrolysis by iminosug- ars should result in nutritional deficiencies and/or disruption of normal osmoregulation. Deoxynojirimycin （DNJ） and 2 N-alk.lated analogs [N-butyl DNJ （NB-DNJ） and N-nonyl DNJ （NN-DNJ）] were the major iminosugars used throughout the study. The extensive experiments conducted with a-glucosidase of the whitefly Bemisia tabaci indicated the competitive nature of inhibition and that the hydrophilic DNJ is a potent inhibitor in com- parison to the more hydrophobic NB-DNJ and NN-DNJ compounds. The same inhibitory pattern was observed with the psyllid Cacopsylla bidens a-glucosidase. In contrast to the above pattern, enzymes of the aphids, Myzus persicae and Aphis gossypii were more sen- sitive to the hydrophobic iminosugars as compared to DNJ. In vivo experiments in which adult B. tabaci were fed dietary iminosugars, show that the hydrophilic DNJ was far less toxic than the lipophilic NB-DNJ and NN-DNJ. It is proposed that this pattern is attributed to the better accessibility of the hydrophobic NN-DNJ to the a-glucosidase membrane- bound compartment in the midgut. Based on the inhibitory effects of certain polyhydroxy N-alk.lated iminosugars, a-glucosidase of phloem feeding hemipterans could serve as an attractive target site for developing novel pest control agents.

关键词： a-glucosidase inhibition Bemisia tabaci Cacopsylla bidens iminosugars Myzuspersicae osmoregulation phloem sap feeders

A Comprehensive Review of Water Quality Monitoring and Assessment in Delta State,Southern Part of Nigeria

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Journal of Environmental & Earth Sciences 2021年第1期3卷 16-28页

作者： Moses Oghenenyoreme Eyank.are Bassey Edem ephraim Department of Geology Ebonyi State University Abakaliki P.M.B.053 Ebonyi StateNigeria Geomoses Consultancy Limited Warri DeltaNigeria Department of Geology University of CalabarP.M.B.1115CalabarCross River StateNigeria

This research presents a review on water resources in Delta state,southern part of Nigeria,with emphasis on hydrogeochemical and microbial *** evaluates factors responsible for water contamination,and their resulting health challenges within the study *** achieve the objective of this study,related articles were downloaded from Google,published article on influence of hydrogeochemical and microbial activities on water *** articles were thoroughly *** from this study,suggested that groundwater was more studied than surface wa*** also observed that groundwater within the riverine communities is much more prone to pollution when compared to groundwater in an upland *** from various authors suggested that,larger percentage of groundwater showed presence of *** findings suggested that geochemical processes such as rock.water interaction,seawater intrusion and precipitation influences groundwater quality within the study area especially within Sombreiro-Warri Deltaic Plain Deposit.

关键词： Geogenic Anthropogenic Hydrogeochemical Cause of pollution Coliform Nigeria

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Asian Pacific Journal of Tropical Medicine 2010年第2期3卷 141-144页

作者： Gyuse AN Bassey IE Udonwa NE Ok.k.n IB Philip-ephraim EE Department of Family Medicine University of Calabar Teaching Hospital Department of Pathology University of Calabar Teaching Hospital Department of Internal Medicine University of Calabar Teaching Hospital

Objective:To determine the causes of death among human immunodeficiency virus/acquired immunodeficiency syndrome(HIV/AIDS) patients as a step to planning strategies to improve mortality from this ***:This study retrospectively analyzed the mortality pattern of adult HIV/AIDS patients in the University of Calabar Teaching Hospital from January 2005 to December *** data were obtained from sexually transmitted infection/acquired immunodeficiency syndrome(STI/AIDS) clinic register,admissions and discharge/death registers as well as the patients’ case records and the hospitals monthly mortality *** obtained included age,sex,diagnosis and cause(s) of *** causes of death considered were the direct causes of death,since the originating antecedent cause of death is the same in all the patients,in this case,HIV/*** was analysed using Epi Info ***:The total number of mortalities during the study period was 350,100 were HIV positive representing 28.6%of all *** advanced HIV/AIDS disease was the leading cause of death in our study representing 27.0%,tuberculosis was the single leading cause of deaths in HIV/AIDS patients constituting about 24.0%of *** was followed by sepsis and septicaemia(13.0%), meningitis and encephalitis,and anaemia accounting for 11.0%,while respiratory diseases constituted 5.0%of the mortality *** highest number of deaths occurred in those aged between 21-50 years(82.0%).Conclusions:The study has shown that HIV/AIDS is a major cause of morbidity and mortality in our *** causes of death reflect the varied spectrum of infection and other forms of organ involvement that affect HIV/AIDS *** present dismal situation of adult patients living with HIV/AIDS calls for enhanced strategies to decrease the mortality trend observed in Nigeria and sub-Saharan Africa.

关键词： Mortality Pattern HIV/AIDS Adult Patients Tertiary health institution

RF-based location of partial discharge sources using received signal features

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High Voltage 2019年第1期4卷 28-32页

作者： ephraim T.Iork.ase Christos Tachtatzis Ian A.Glover Robert C.Atk.nson Department of Electronic and Electrical Engineering University of StrathclydeRoyal College Building204 George StreetGlasgow G11XWUK Department of Engineering and Technology University of HuddersfieldHD13DH HuddersfieldUK

Partial discharges(PDs)are symptomatic of some localised defects in the insulation system of electrical *** activity emits electrical pulses in the form of radio frequency(RF)signals which can be captured using appropriate *** analysis of the measured RF signals facilitates localisation of *** study investigates the plausibility of using purely RF received signal features of PD pulses to locate PD at low cost.A localisation approach based on the analysis of these features has been developed,with the assumption that PDs generate unique RF spatial patterns due to the complexities and nonlinearities of RF *** this approach,two distinct frequency bands which hold different PD information are *** location features are extracted from the main PD signal and the two sub-band ***-based feature selection(CFS)is employed for feature selection and dimensionality *** results show that PD location can be inferred from the features of the PD *** application of CFS to PD data reduces the memory/computational demand and improves localisation accuracy.

关键词： signal features electrical

Field-level characterization of strong coupling between excitons and surface plasmon polaritons in J-aggregate/metal hybrid nanostructures

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光电工程 2017年第2期44卷 202-208+242页

作者： Wei Wang ephraim Sommer Antonietta De Sio Parinda Vasa Juemin Yi Hong Zhang College of Physical Science and Technology Sichuan University Institut für Physik Carl von Ossietzky Universit?t k.y Laboratory of High Energy Density Physics and Technology of Ministry of Education Sichuan University Department of Physics Indian Institute of Technology

White-light broadband chirp-compensated spectral interferometry is applied to fully probe the optical response of strongly coupled excitons(Xs)and surface plasmon polaritons(SPPs)in J-aggregate/metal hybrid nanostructures at field *** impulsive excitation,amplitude and spectral phase of the sample reflectivity are measured with high precision and the time structure of the electric field emitted by the hybrid modes of the nanostructures is accurately *** description of strong X-SPP coupling is precisely obtained by fitting both measured spectra and phases simultaneously to a Fano lineshape model.

关键词： surface plasmon polaritons spectral interferometry subwavelength nanostructures strong coupling

Valproic acid and nonalcoholic fatty liver disease: A possible association?

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World Journal of Hepatology 2015年第9期7卷 1251-1257页

作者： Edoardo Farinelli David Giampaoli Anja Cenciarini ephraim Cercado Alberto Verrotti Department of Pediatrics University of Perugia General Surgery Department Lung Center of the Philippines Quezon Avenue Diliman Quezon City 1101Metro Manila Philippines

Valproic acid(VPA) is one of the most prescribed drugs in children with newly diagnosed epilepsy. Weight gain and obesity have been observed as side effects of VPA. These are often link.d with other metabolic disturbances such as development of insulin resistance, dyslipidemia, metabolic syndrome(Met S) and nonalcoholic fatty liver disease or nonalcoholic fatty liver disease(NAFLD). NAFLD refers to a group of liver disorders with mark.d hepatic steatosis. It is associated with an increased incidence of cardiovascular diseases and overall reduced life expectancy. NAFLD occurs in 20%-25% of the general population and it is k.own to be the most common cause of chronic liver disease. NAFLD therefore represents a major public health issue worldwide. This study reviews and summarizes relevant literature that supports the existence of an association between VPA therapy and the development of NAFLD in children. Long-term VPA-therapy appears to be associated with an increased risk.of developing NAFLD. Further studies are needed to clarify the pathogenic mechanisms that lie behind this association and to standardize the options for the use of this drug in overweight patients and in those with risk. for developing Met S and NAFLD.

关键词： Nonalcoholic fatty liver disease Valproicacid Obesity Insulin resistance