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Forest Ecosystems 2022年第4期9卷 439-448页

作者： Anthony Amoah Adusei Jumah Kofi Korle School of Sustainable Development University of Environment and Sustainable DevelopmentSomanyaGhana&Africa Centre for Economics and Policy Research(ACAEP)Ghana Department of Economics Central UniversityAccraGhana

In recent years, debates on the alarming rate of forest depletion emanating from growth in urban settlement and changed urban land-use patterns have gained prominence across the globe. The present study adopts a demandside management approach to investigate household’s willingness-to-pay for the restoration and maintenance of protected forest reserves in three municipalities in Ghana. Using survey data of 733 households from the Greater Accra Region of Ghana, we model the demand for forest restoration and maintenance, respectively, by means of the contingent valuation technique. As part of the findings, the study shows evidence that a household is willing to pay Gh￠50.99($8.67) and Gh￠31.12($5.29) per annum to restore and maintain the protected forests,respectively. These amounts constitute less than one percent of the average household income per month.Consequently, critical validity tests are conducted to validate the robustness of the results. This study provides willingness-to-pay estimates for forest and forest resources, and its associated determinants. These estimates seek to bridge the information gap and inform policy decisions toward the overarching aim of ensuring sustainable forest management in Ghana.

关键词： Reserved forest Restoration Maintenance Tobit model Willingness-to-pay CVM

Constitutive STAT3 phosphorylation and IL-6/IL-10 co-expression are associated with impaired T-cell function in tuberculosis patients

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Cellular & Molecular Immunology 2019年第3期16卷 275-287页

作者： Kirstin Harling Ernest Adankwah Alptekin Güler anthony Afum-Adjei Awuah Louis Adu-amoah Ertan Mayatepek Ellis Owusu-Dabo Norman Nausch Marc Jacobsen Department of General Pediatrics Neonatologyand Pediatric CardiologyUniversity Children’s HospitalDuesseldorf 40225Germany Kumasi Centre for collaborative Research in Tropical Medicine(KCCR) KumasiGhana School of Public Health College of Health SciencesKwame Nkrumah University of Science and Technology(KNUST)KumasiGhana

T-cells critically contribute to protection against Mycobacterium tuberculosis infection,and impaired T-cell responses can lead to disease progression.Pro-inflammatory and immunosuppressive cytokines affect T-cells,and fine-tuned regulation of cytokine signaling via the Jak/STAT signaling pathways is crucial for appropriate T-cell function.Constitutive STAT3 phosphorylation as a consequence of aberrant cytokine signaling has been described to occur in pathognomonic T-cell responses in inflammatory and autoimmune diseases.We characterized blood samples from tuberculosis patients(n=28)and healthy contacts(n=28)from Ghana for M.tuberculosis-specific T-cell responses,constitutive cytokine production,and SOCS3 and pSTAT3 expression.Lentiviral modulation of primary CD4+T-cells was performed to determine the effects of SOCS3 on T-cell functions.T-cells from tuberculosis patients expressed higher levels of IL-10 and IL-6 and lower levels of T helper type(TH)17 cytokines after M.tuberculosis-specific stimulation compared to healthy contacts.In addition,tuberculosis patients had higher IL-10 and IL-6 levels in the supernatants of non-stimulated immune cells and plasma samples compared to healthy contacts.Notably,aberrant cytokine expression was accompanied by high constitutive pSTAT3 levels and SOCS3 expression in T-cells.Multivariate analysis identified an IL-6/IL-10 co-expression-based principal component in tuberculosis patients that correlated with high pSTAT3 levels.SOCS3 contributed to a regulatory component,and tuberculosis patients with high SOCS3 expression showed decreased TH1 cytokine expression and impaired IL-2-induced STAT5 phosphorylation.SOCS3 over-expression in primary CD4+T-cells confirmed the SOCS3 inhibitory function on IL-2-induced STAT5 phosphorylation.We conclude that constitutive pSTAT3 and high SOCS3 expression are influential factors that indicate impaired T-cell functions in tuberculosis patients.

关键词： tuberculosis Interleukin-6 Interleukin-10 STAT3 SOCS3

Extrauterine Pregnancy: A Nine-Year Review of Incidence, Seasonality and Management at a Tertiary Hospital in Southern Ghana

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Open Journal of Obstetrics and Gynecology 2020年第2期10卷 264-274页

作者： Evans Kofi Agbeno anthony Amanfo Ofori Joseph Osarfo Doughan Samuel Joseph amoah Adu Sebastien Ken-amoah Wisdom Klutse Azanu Department of Obstetrics and Gynaecology School of Medical Sciences University of Cape Coast Cape Coast Ghana Department of Obstetrics and Gynaecology Cape Coast Teaching Hospital Cape Coast Ghana Ghana Health Service Asante Mampong Municipal Hospital Asante Mampong Ghana Department of Obstetrics and Gynaecology School of Medicine University of Health and Allied Sciences Ho Ghana

Introduction: Most cases of extrauterine pregnancies present in the ruptured state in low-resource settings and patients with haemodynamic instability risk mortality without swift intervention. An idea of when ectopic gestations are likely to present may be useful for logistic planning and facility readiness for case management. The study sought to assess the incidence of extrauterine gestation, mode of management and any link with seasonal and/or sociocultural events within the Cape Coast metropolis of Ghana over a 9-year review period.?Methods: A retrospective review of all cases of extrauterine pregnancies managed at the Cape Coast Teaching Hospital (CCTH) from January 2010 to December 2018 was conducted. Data on patient age, parity, month of presentation, site and laterality of ectopic gestation, number of abortions and deliveries were retrieved from hospital records and analysed. Yearly and monthly aggregated incidence of extrauterine pregnancies were computed.?Result: A total of 480 ectopic pregnancies out of 26,850 total pregnancies were seen over the period, giving an overall occurence of 17.9/1000 pregnancies and almost all were managed surgically. Half of all the cases occurred in the 20?-?29 years age group while the extremes of age recorded the lowest. An average of about 53 cases per year was recorded for the period under review. The peak months of occurrence were October and November. About 83% were ruptured with the ampulla region being the commonest site. Conclusion: The data suggests increased ectopic gestation occurrence in the Cape Coast metropolis about two months after the major traditional festivals and this may have implications for instituting mitigating measures, logistic management and facility preparedness for case management.

关键词： Extrauterine Pregnancy Seasonality Incidence Ghana Management Options

Investigation of Acoustomagnetoelectric Effect in Bandgap Graphene by the Boltzmann Transport Equation

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World Journal of Condensed Matter Physics 2024年第1期14卷 10-20页

作者： Raymond Edziah Samuel S. Bentsiefi Kwadwo Dompreh anthony Twum Emmanuel Kofi Amewode Patrick Mensah-amoah Ebenezer T. Tatchie Cynthia Jebuni-Adanu Samuel Y. Mensah Department of Physics University of Cape Coast Cape Coast Ghana Department of Physics Education University of Education Winneba Ghana

We study the acoustomagnetoelectric (AME) effect in two-dimensional graphene with an energy bandgap using the semiclassical Boltzmann transport equation within the hypersound regime, (where represents the acoustic wavenumber and is the mean free path of the electron). The Boltzmann transport equation and other relevant equations were solved analytically to obtain an expression for the AME current density, consisting of longitudinal and Hall components. Our numerical results indicate that both components of the AME current densities display oscillatory behaviour. Furthermore, geometric resonances and Weiss oscillations were each defined using the relationship between the current density and Surface Acoustic Wave (SAW) frequency and the inverse of the applied magnetic field, respectively. Our results show that the AME current density of bandgap graphene, which can be controlled to suit a particular electronic device application, is smaller than that of (gapless) graphene and is therefore, more suited for nanophotonic device applications.

关键词： Boltzmann Transport Equation Acoustomagnetoelctric Effect Surface Acoustic Wave Gapless Graphene Weiss Oscillations

Temperature Dependent Resistivity of Chiral Single-Walled Carbon Nanotubes in the Presence of Coherent Light Source

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World Journal of Condensed Matter Physics 2021年第4期11卷 77-86页

作者： anthony Twum Raymond Edziah Samuel Yeboah Mensah Kwadwo Dompreh Patrick Mensah-amoah Augustine Arthur Natalia G. Mensah Kofi Adu George Nkrumah-Buandoh Department of Physics University of Cape Coast Cape Coast Ghana Department of Mathematics University of Cape Coast Cape Coast Ghana Department of Physics The Pennsylvania State University-Altoona College Altoona USA Department of Physics University of Ghana Accra Ghana

We have studied the axial resistivity of chiral single-walled carbon nanotubes (SWCNTs) in the presence of a combined direct current and high frequency alternating fields. We employed semiclassical Boltzmann equations approach and compared our results with a similar study that examined the circumferential resistivity of these unique materials. Our work shows that these materials display similar resistivity for both axial and circumferential directions and this largely depends on temperature, intensities of the applied fields and material parameters such as chiral angle. Based on these low-temperature bidirectional conductivity responses, we propose chiral SWCNTs for design of efficient optoelectronic devices.

关键词： Chiral Single-Wall Carbon Nanotubes Boltzmann Transport Equation Axial Resistivity Chiral Angle

Direct Current Generation in Carbon Nanotubes by Terahertz Field

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World Journal of Condensed Matter Physics 2016年第1期6卷 56-62页

作者： Sulemana S. Abukari Frederick Sam Samuel Y. Mensah Natalia G. Mensah Rabiu Musah anthony Twum Patrick M. amoah Alfred Owusu Department of Physics Laser and Fibre Optics Centre University of Cape Coast Cape Coast Ghana Department of Mathematics University of Cape Coast Cape Coast Ghana Department of Applied Physics University for Development Studies Navorongo Ghana

We report on a theoretical investigation of a direct current generation in carbon nanotubes (CNTs) that are stimulated axially by terahertz (THz) field. We consider the kinetic approach based on the semiclassical Boltzmann’s transport equation with constant relaxation time approximation, together with the energy spectrum of an electron in the tight-binding approximation. Our results indicate that for strong THz-fields, there is simultaneous generation of DC current in the axial and circumferential directions of the CNTs, even at room temperature. We found that a THz-field can induce a negative conductivity in the CNTs that leads to the THz field induced DC current. For varying amplitude of the THz-field, the current density decreases rapidly and modulates around zero with interval of negative conductivity. The interval decreases with increasing the amplitude of the THz-field. We show that the THz-field can cause fast switching from a zero DC current to a finite DC current due to the quasi-ballistic transport, and that electron scattering is a necessary condition for switching.

关键词： Carbon Nanotubes Terahertz Fields DC Voltage Generation Negative Conductivity Electron Scattering Ballistic Transport

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