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External Electric Field Effect on Electrons Transport in Carbon Nanotubes

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World Journal of Condensed Matter Physics 2013年第4期3卷 169-172页

作者： Sulemana S. Abukari Samuel Y. Mensah Musah Rabiu Kofi W. Adu Natalia G. Mensah Kwadwo A. Dompreh Anthony Twum matthew amekpewu Department of Applied Physics University for Development Studies Navorongo Ghana Department of Mathematics University of Cape Coast Cape Coast Ghana Department of Physics Laser and Fibre Optics Centre University of Cape Coast Cape Coast Ghana Department of Physics The Pennsylvania State University Altoona USA Materials Research Institute The Pennsylvania State University University Park USA

We consider a simple model of carbon nanotubes (CNTs) subject to external electric field E(t). Using a tight-binding approximation for the description of energy bands of CNTs, together with the standard Boltzmann transport equation and constant relaxation time, we predict the effect of self-induced transparency and absolute negative conductivity. The predicted effects may be useful in diagnostics of carbon nanotubes as well as in the amplification and efficiency conversion of electromagnetic signals.

关键词： Carbon Nanotubes Electric Field Electric Current Density Negative Differential Conductivity

High-Frequency Electric Field Induced Nonlinear Electron Transport in Chiral Carbon Nanotubes

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World Journal of Condensed Matter Physics 2015年第4期5卷 294-300页

作者： Sulemana S. Abukari Samuel Y. Mensah Musah Rabiu Kofi W. Adu Natalia G. Mensah Anthony Twum Alfred Owusu Kwadwo A. Dompreh Patrick Mensah-Amoah matthew amekpewu Department of Physics Laser and Fibre Optics Centre University of Cape Coast Cape Coast Ghana Department of Applied Physics University for Development Studies Navorongo Ghana Department of Physics The Pennsylvania State University-Altoona Altoona USA Materials Research Institute The Pennsylvania State University University Park USA Department of Mathematics University of Cape Coast Cape Coast Ghana

We investigate theoretically the high frequency complex conductivity in carbon nanotubes that are stimulated axially by a strong inhomogeneous electric field of the form E(t)=E0+E1cos(ωt). Using the kinetic approach based on Boltzmann’s transport equation with constant relaxation time approximation and the energy spectrum of the electron in the tight-binding approximation, together with Bhatnagar-Gross-Krook collision integral, we predict high-frequency nonlinear effects along the axial and the circumferential directions of the carbon nanotubes that may be useful for the generation of high frequency radiation in the carbon nanotubes.

关键词： Carbon Nanotubes High Frequency Electric Field Electric Current Density Complex Conductivity

Domain Suppression in the Negative Differential Conductivity Region of Carbon Nanotubes by Applied AC Electric Field

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World Journal of Condensed Matter Physics 2012年第4期2卷 274-277页

作者： Sulemana S. Abukari Samuel Y. Mensah Kofi W. Adu Natalia G. Mensah Kwadwo A. Dompreh Anthony Twum Chales L. Y. Amuah matthew amekpewu Musah Rabiu Department of Applied Physics University for Development Studies Navorongo Ghana Department of Physics Laser and Fibre Optics Centre University of Cape Coast Cape Coast Ghana Department of Physics The Pennsylvania State University Altoona USA Materials Research Institute The Pennsylvania State University University Park USA National Centre for Mathematical Sciences Ghana Atomic Energy Commission Accra Ghana Department of Mathematics University of Cape Coast Cape Coast Ghana

We study theoretically the electron transport properties in achiral carbon nanotubes under the influence of an external electric field E(t) using Boltzmann’s transport equation to derive the current-density. A negative differential conductivity (NDC) is predicted in quasi-static approximation i.e., ωτ 0 is equal to the amplitude of the AC electric field E1. The peak of the NDC intensity occurs at very weaker fields than that of superlattice under the same conditions. The peak intensity decreases and shifts to right with the increase in the amplitude of the ac field. This mechanism suppresses the domain formation and therefore could be used in terahertz frequency generation.

关键词： Carbon Nanotubes Negative Differential Conductivity and Generation of Terahertz Radiation

Alterations of SARS-CoV-2 Evolutionary Dynamics by Pharmaceutical Factors

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Infectious Diseases & Immunity 2024年第1期4卷 35-40页

作者： matthew Halma EbMCsquared CIC Bath BA24BLUnited Kingdom

The outbreak of SARS-CoV-2(severe acute respiratory syndrome coronavirus 2)has been influenced by the human response to the *** responses have undoubtedly impacted the evolutionary dynamics of the virus in ways distinct from a scenario lacking a widespread *** important pharmaceutical interventions,vaccination and the utilization of medications,particularly molnupiravir,known to have mutagenic properties,were the focus of this *** impact of molnupiravir on human health was evaluated through 3 mechanisms:viral resistance,mutagenesis of SARS-CoV-2,and mutagenesis occurring in patients undergoing ***,as well as the impact of vaccination,have inadvertently given rise to unforeseen challenges in the management of the COVID-19 *** a systems view in future pandemic responses,and taking into account the evolution of the pandemic virus,may be critical to ending the pandemic at an earlier date.

关键词： COVID-19 SARS-CoV-2 Evolution Spike protein Molnupiravir Mutagenesis

Evaluation of a software positioning tool to support SMEs in adoption of big data analytics

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Journal of Electronic Science and Technology 2024年第1期22卷 13-24页

作者： matthew Willetts Anthony S.Atkins Faculty of Digital TechnologyInnovationand BusinessStaffordshire UniversityStoke-on-TrentST42DEUnited Kingdom

Big data analytics has been widely adopted by large companies to achieve measurable benefits including increased profitability,customer demand forecasting,cheaper development of products,and improved stock *** and medium sized enterprises(SMEs)are the backbone of the global economy,comprising of 90%of businesses ***,only 10%SMEs have adopted big data analytics despite the competitive advantage they could *** research has analysed the barriers to adoption and a strategic framework has been developed to help SMEs adopt big data *** framework was converted into a scoring tool which has been applied to multiple case studies of SMEs in the *** paper documents the process of evaluating the framework based on the structured feedback from a focus group composed of experienced *** results of the evaluation are presented with a discussion on the results,and the paper concludes with recommendations to improve the scoring tool based on the proposed *** research demonstrates that this positioning tool is beneficial for SMEs to achieve competitive advantages by increasing the application of business intelligence and big data analytics.

关键词： Big data analytics Evaluation Small and medium sized enterprises (SMEs) Strategic framework

Refining safety considerations for intradialytic blood flow restriction exercise. Commentary on “Concerns on the application of blood-flow restriction resistance exercise and thrombosis risk in hemodialysis patients”

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Journal of Sport and Health Science 2024年第4期13卷 455-456页

作者： matthew J.Clarkson Institute for Health and Sport Victoria UniversityMelbourneVIC 8001Australia

I read with great interest the article“Concerns on the application of blood flow restriction resistance exercise and thrombosis risk in hemodialysis patients”by Correa et al.1 The study presents complementary data from a previous randomized controlled trial,2 exploring the application of intradialytic blood flow restriction exercise for hemodialysis patients.

关键词： patients hemodialysis

Description of a novel robotic early post-prostatectomy anastomotic repair technique and institutional outcomes

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Asian Journal of Urology 2024年第3期11卷 366-372页

作者： David Strauss Eric Cho matthew Loecher matthew Lee Daniel Eun Department of Urology Lewis Katz School of MedicineTemple UniversityPhiladelphiaPAUSA

Objective:A vesicourethral anastomotic leak(VUAL)is a known complication following robotic-assisted radical *** natural history of a VUAL has been well described and is frequently managed with prolonged *** increasing emphasis on patient reported outcomes,catheter duration and VUAL are associated with significant short-term quality of life *** aimed to present a case series of our robotic early post-prostatectomy anastomotic repair technique,defined as revision within 6 weeks from index ***:A single institution prospective database identified eleven patients with a VUAL from July 2016 to October 2022 who underwent robotic early post-prostatectomy anastomotic repair by a single *** were diagnosed with a VUAL on pre-operative CT urogram or CT/fluoroscopic *** primary outcome was resolution of the anastomotic leak,defined as no contrast extravasation on post-operative *** outcomes included post-repair catheter duration and continence on the last follow-up defined as pad(s)per ***:The mean time to intervention after robotic-assisted radical prostatectomy was 21 *** of the eleven(72.7%)patients had no evidence of extravasation on postrepair *** range from intervention to first cystogram was 7e20 *** median catheter duration for those with successful intervention was 10 *** median catheter duration for those with the leak on initial post-operative cystogram was 20 *** a mean follow-up time of 25 months,eight(72.7%)patients reported using no pads per day,and three(27.3%)patients reported one pad per ***:Management of a VUAL has traditionally relied on prolonged catheter drainage and the tincture of *** the role of robotic reconstruction has been shown to be a viable modality for management of bladder neck contracture,it is important to reconsider prior dogmas of urologic *** case series suggests that an early repair is saf

关键词： Minimallyinvasive surgery Vesicourethral anastomotic leak Robotic-assisted laparoscopic reconstruction

Water quality, habitat, and fish assemblage relationships in middle-order agriculture and forest streams of the Mississippi Alluvial Plain

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Ecological Processes 2024年第01期13卷 217-236页

作者： matthew L.Skoog Michael A.Eggleton Yushun Chen Department of Aquaculture and Fisheries University of Arkansas at Pine Bluff Minnesota Department of Natural Resources State Key Laboratory of Freshwater Ecology and Biotechnology Institute of Hydrobiology Chinese Academy of Sciences University of Chinese Academy of Sciences

Background Agriculture has greatly influenced water quality, habitats, and fish assemblages in streams of the Mississippi Alluvial Plain(MAP) ecoregion. However, MAP streams have historically been understudied compared to streams in other agricultural regions of the USA. In this study, water quality, habitat, and fish assemblage composition were assessed seasonally(spring, summer, and fall) in eight representative MAP streams located across three U.S. states. The study design included four streams containing highly agricultural watersheds(herein termed “agriculture” streams) and four streams containing mostly forested watersheds(herein termed “forest” streams), which were intended to represent reference conditions for MAP *** In general, forest streams contained significantly better instream and riparian habitats than agriculture streams(P = 0.010–0.040) whereas agriculture streams contained significantly greater levels of primary nutrients(P < 0.001–0.010). Differences between agriculture and forest streams with respect to other physical and chemical variables were intermittent and season dependent. Fish assemblages in agriculture and forest streams were structured primarily along an environmental gradient reflecting instream habitat conditions, water nutrient concentrations, and benthic chlorophyll-a production. Structurally, fish assemblages in both stream types contained many regionally common species, though some species appeared to exhibit affinities for a particular stream type. Functionally, fish assemblages in agriculture streams contained more tolerant species, more omnivores, and fewer insectivores compared to forest stream assemblages, which were nearly all insectivores. Overall, one-third of the fish specimens collected in forest streams classified as intolerant *** Our results suggested that stream water quality, habitat, and fish assemblages differed between agriculture and forest streams in the MAP, with fish assemblages e

关键词： Agriculture Stream Land use Water quality Habitat Fish Multivariate statistics Mississippi Alluvial Plain

Runx2 regulates peripheral nerve regeneration to promote Schwann cell migration and re-myelination

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Neural Regeneration Research 2024年第7期19卷 1575-1583页

作者： Rong Hu Xinpeng Dun Lolita Singh matthew C.Banton School of Traditional Chinese Medicine Department of Traditional Chinese MedicineNanfang HospitalSouthern Medical UniversityGuangzhouGuangdong ProvinceChina The Co-innovation Center of Neuroregeneration Nantong UniversityNantongJiangsu ProvinceChina Faculty of Health University of PlymouthPlymouthUK

Runx2 is a major regulator of osteoblast differentiation and function;however,the role of Runx2 in peripheral nerve repair is unclea ***,we analyzed Runx2expression following injury and found that it was specifically up-regulated in Schwann ***,using Schwann cell-specific Runx2 knocko ut mice,we studied peripheral nerve development and regeneration and found that multiple steps in the regeneration process following sciatic nerve injury were *** observed in Runx2 knoc kout mice include increased prolife ration of Schwann cells,impaired Schwann cell migration and axonal regrowth,reduced re-myelination of axo ns,and a block in macrophage clearance in the late stage of *** together,our findings indicate that Runx2 is a key regulator of Schwann cell plasticity,and therefore peripheral nerve ***,our study shows that Runx2 plays a major role in Schwann cell migration,re-myelination,and peripheral nerve functional recovery following injury.

关键词： macrophage clearance migration peripheral nerve injury regeneration re-myelination Runx2 Schwann cells