34 research outputs found
Ecotourism Potentials in Bayelsa State
This survey was carried out in Bayelsa State in specific areas such as Ogbia, Yenagoa, Brass, Kaiama, Akassa and Amassoma to determine the ecotourism potentials in the state. Frequency distribution and percentages were used to describe the analysis. The age group distribution respondents showed that age group 41 – 50 (23.25%) had the highest response, followed by 51 – 60 (22.0%) and 61 – 70 (20.75%), 30 – 40 (20.25%) and 71 – 80 (13.75%). The occupational distribution of respondents showed that the highest number of respondents are students (24.88%) while farmers are (22.91%) followed by traders (18.72%), driving/fishing is (17.49%) and civil servants (16.01%). On awareness of ecotourism potentials in the various communities, the highest number was at Ogbia (16) and Yenagoa (15) followed by Akassa (9), Amassoma (8), Brass (7) and Kaiama (6). Since there are ecotourism potentials in Bayelsa State the Government should provide funds at the local and state level to develop them
A Predictive Analytical Model of Thermal Conductivity for Aluminum/Transition Metal High Entropy Alloys
A predictive analytical model for the thermal conductivity of aluminum/transition metal based high-entropy alloys based on contributions from the electron and lattice subsystems is presented. Lattice conductivity is modeled as an oscillator damped by electron-phonon and defect scattering. Electron subsystem conductivity is dominated by scattering from the aperiodic crystal potential arising from alloying atom induced lattice disorder; its effect was quantitatively calculated using a virtual crystal approximation. We show that model predictions agree with published values and for an exemplar high-entropy alloy largely based on transition (i.e., non-refractory) elements, AlxCoCrCuyFeNi. Within this alloy system, the crystal structure varies between face centered cubic and body centered cubic depending on composition and temperature, and it was found that thermal conductivity behaves as a weighted-average composite of the multiple phases
Inhibiting the recruitment of PLCγ1 to Kaposi's Sarcoma Herpesvirus K15 protein reduces the invasiveness and angiogenesis of infected endothelial cells.
Kaposi's sarcoma (KS), caused by Kaposi's sarcoma herpesvirus (KSHV), is a highly vascularised tumour of endothelial origin. KSHV infected endothelial cells show increased invasiveness and angiogenesis. Here, we report that the KSHV K15 protein, which we showed previously to contribute to KSHV-induced angiogenesis, is also involved in KSHV-mediated invasiveness in a PLCγ1-dependent manner. We identified βPIX, GIT1 and cdc42, downstream effectors of PLCγ1 in cell migration, as K15 interacting partners and as contributors to KSHV-triggered invasiveness. We mapped the interaction between PLCγ1, PLCγ2 and their individual domains with two K15 alleles, P and M. We found that the PLCγ2 cSH2 domain, by binding to K15P, can be used as dominant negative inhibitor of the K15P-PLCγ1 interaction, K15P-dependent PLCγ1 phosphorylation, NFAT-dependent promoter activation and the increased invasiveness and angiogenic properties of KSHV infected endothelial cells. We increased the binding of the PLCγ2 cSH2 domain for K15P by substituting two amino acids, thereby creating an improved dominant negative inhibitor of the K15P-dependent PLCγ1 activation. Taken together, these results demonstrate a necessary role of K15 in the increased invasiveness and angiogenesis of KSHV infected endothelial cells and suggest the K15-PLCγ1 interaction as a possible new target for inhibiting the angiogenic and invasive properties of KSHV
Extreme hardness at high temperature with a lightweight additively manufactured multi-principal element superalloy
Materials are needed that can tolerate increasingly harsh environments, especially ones that retain high strength at extreme temperatures. Higher melting temperature alloys, like those consisting primarily of refractory elements, can greatly increase the efficiency of turbomachinery used in grid electricity production worldwide. Existing alloys, including Ni- and Co-based superalloys, used in components like turbine blades, bearings, and seals, remain a performance limiting factor due to their propensity, despite extensive optimization efforts, for softening and diffusion-driven elongation at temperatures often well above half their melting point. To address this critical materials challenge, we present results from integrating additive manufacturing and alloy design to guide significant improvements in performance via traditionally difficult-to-manufacture refractory alloys. We present an example of a multi-principal element alloy (MPEA), consisting of five refractory elements and aluminum, that exhibited high hardness and specific strength surpassing other known alloys, including superalloys. The alloy shows negligible softening up to 800°C and consists of four compositionally distinct phases, in distinction to previous work on MPEAs. Density functional theory calculations reveal a thermodynamic explanation for the observed temperature-independent hardness and favorability for the formation of this multiplicity of phases.This article is published as Kustas, Andrew B., Morgan R. Jones, Frank W. DelRio, Ping Lu, Jonathan Pegues, Prashant Singh, A. V. Smirnov et al. "Extreme hardness at high temperature with a lightweight additively manufactured multi-principal element superalloy." Applied Materials Today 29 (2022): 101669.
DOI: 10.1016/j.apmt.2022.101669.
Copyright 2022 The Authors.
Attribution 4.0 International (CC BY 4.0).
Posted with permission.
DOE Contract Number(s): AC02-07CH11358; NA000352