1,727 research outputs found

    Coupling of Biomass Gasification and SOFC – Gas Turbine Hybrid System for Small Scale Cogeneration Applications☆

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    Abstract In this study the performances of small cogeneration power plants fed by biomass and based on conventional and advanced technologies are presented. Three system configurations have been considered and analyzed. They are characterized by: a) a biomass gasification (G) unit, based on down-draft technology; b) a power unit, based on the SOFC technology or on the micro gas turbine (MGT) technology or on a hybrid configuration SOFC-MGT; c) a thermal recovery unit. The energy analysis of the proposed power plants has been conducted by using thermochemical/thermodynamic models able to study the integrated systems and each unit in terms of operating and performance parameters

    THE EFFECTS OF WHEELCHAIR CAMBER AND HANDRIM SIZE IN WHEELCHAIR BASKETBALL MOVEMENT

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    Improving the wheelchair design can be an important determinant of high performance in the wheelchair basketball. Researchers have focused on increasing the efficiency of the wheelchair, looking at the factors such as the seat position, handrim size, and wheel camber. Most handrim and wheel chamber studies, however, have focused only on the propulsive phase. Quick turn as well as fast propulsion is essential to the success in a wheelchair basketball game and the energy efficiency becomes particularly important in a prolonged wheelchair use. The purpose of this study was to investigate the effects of wheelchair camber and handrim size on the linear propulsion, turn velocity, and efficiency

    Energy Flow Boundary Element Method for Vibration Analysis of One and Two Dimension Structures

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    In this paper, Energy Flow Boundary Element Method (EFBEM) was developed to predict the vibration behavior of one- and two-dimensional structures in the medium-to-high frequency ranges. Free Space Green functions used in the method were obtained from EFA energy equations. Direct and indirect EFBEMs were formulated for both one- and two-dimensional cases, and numerically applied to predict the energy density and intensity distributions of simple Euler-Bernoulli beams, single rectangular thin plates, and L-shaped thin plates vibrating in the medium-to-high frequency ranges. The results from these methods were compared with the EFA solutions to verify the EFBEM

    Stimulation of the Migration and Expansion of Adult Mouse Neural Stem Cells by the FPR2-Specific Peptide WKYMVm

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    Neural stem cells (NSCs) are multipotent cells capable of self-renewal and differentiation into different nervous system cells. Mouse NSCs (mNSCs) are useful tools for studying neurogenesis and the therapeutic applications of neurodegenerative diseases in mammals. Formyl peptide receptor 2 (FPR2), expressed in the central nervous system and brain, is involved in the migration and differentiation of murine embryonic-derived NSCs. In this study, we explored the effect of FPR2 activation in adult mNSCs using the synthetic peptide Trp-Lys-Tyr-Met-Val-D-Met-NH2 (WKYMVm), an agonist of FPR2. After isolation of NSCs from the subventricular zone of the adult mouse brain, they were cultured in two culture systems—neurospheres or adherent monolayers—to demonstrate the expression of NSC markers and phenotypes. Under different conditions, mNSCs differentiated into neurons and glial cells such as astrocytes, microglia, and oligodendrocytes. Treatment with WKYMVm stimulated the chemotactic migration of mNSCs. Moreover, WKYMVm-treated mNSCs were found to promote proliferation; this result was confirmed by the expansion of mNSCs in Matrigel and the increase in the number of Ki67-positive cells. Incubation of mNSCs with WKYMVm in a supplement-free medium enhanced the survival rate of the mNSCs. Together, these results suggest that WKYMVm-induced activation of FPR2 stimulates cellular responses in adult NSCs. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.1

    Evolution of ribosomal DNA-derived satellite repeat in tomato genome

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    <p>Abstract</p> <p>Background</p> <p>Tandemly repeated DNA, also called as satellite DNA, is a common feature of eukaryotic genomes. Satellite repeats can expand and contract dramatically, which may cause genome size variation among genetically-related species. However, the origin and expansion mechanism are not clear yet and needed to be elucidated.</p> <p>Results</p> <p>FISH analysis revealed that the satellite repeat showing homology with intergenic spacer (IGS) of rDNA present in the tomato genome. By comparing the sequences representing distinct stages in the divergence of rDNA repeat with those of canonical rDNA arrays, the molecular mechanism of the evolution of satellite repeat is described. Comprehensive sequence analysis and phylogenetic analysis demonstrated that a long terminal repeat retrotransposon was interrupted into each copy of the 18S rDNA and polymerized by recombination rather than transposition via an RNA intermediate. The repeat was expanded through doubling the number of IGS into the 25S rRNA gene, and also greatly increasing the copy number of type I subrepeat in the IGS of 25-18S rDNA by segmental duplication. Homogenization to a single type of subrepeat in the satellite repeat was achieved as the result of amplifying copy number of the type I subrepeat but eliminating neighboring sequences including the type II subrepeat and rRNA coding sequence from the array. FISH analysis revealed that the satellite repeats are commonly present in closely-related <it>Solanum </it>species, but vary in their distribution and abundance among species.</p> <p>Conclusion</p> <p>These results represent that the dynamic satellite repeats were originated from intergenic spacer of rDNA unit in the tomato genome. This result could serve as an example towards understanding the initiation and the expansion of the satellite repeats in complex eukaryotic genome.</p

    Strong carrier localization and diminished quantum-confined Stark effect in ultra-thin high-indium-content InGaN quantum wells with violet light emission

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    Here, we report on the optical and structural characteristics of violet-light-emitting, ultra-thin, high-Indium-content (UTHI) InGaN/GaN multiple quantum wells (MQWs), and of conventional low-In-content MQWs, which both emit at similar emission energies though having different well thicknesses and In compositions. The spatial inhomogeneity of In content, and the potential fluctuation in high-efficiency UTHI MQWs were compared to those in the conventional low-In-content MQWs. We conclude that the UTHI InGaN MQWs are a promising structure for achieving better quantum efficiency in the visible and near-ultraviolet spectral range, owing to their strong carrier localization and reduced quantum-confined Stark effect.open0

    Isolation and characterization of differentially expressed genes in the mycelium and fruit body of Pleurotus ostreatus

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    The fruiting body of one of the most widely cultivated mushrooms, the oyster mushroom (Pleurotus ostreatus) is highly interesting, both commercially and scientifically. In the present study, we performed comparative proteomic profiling of P. ostreatus at two unique developmental stages; mycelium and fruit body, using two-dimensional gel electrophoresis (2-DE). Seven hundred fourteen (714) spots were detected and 29 spots (showing a high level of difference in their expressions) were identified by tandem mass spectrometry and basic local alignment search tool (BLAST) searching of an expressed sequence tag (EST) database of P. ostreatus. Among them, six proteins (putative fatty acid oxygenase, heat shock sks2, PriA homologue, Ap-1 like transcription factor YAP7, mung bean seed albumin, and C2H2 Zinc finger domain protein) and one protein (peroxisomal biogenesis factor 6) showed increased expression levels at the fruiting process and the mycelial stage, respectively. Through reverse transcriptase-polymerase chain reaction analysis, priA homologue and AP-1 like transcription factor yap7 showed gradually increased expression from mycelia to fruit body, whereas putative fatty acid oxygenase and heat shock protein sks2 were expressed only in the fruit body. These results provide useful information for future studies of mushroom development of P. ostreatus.Keywords: Developmental stage, mushroom fruiting, Pleurotus ostreatus, protein, two-dimensional gel electrophoresisAfrican Journal of Biotechnology Vol. 12(24), pp. 3790-379

    Calcified Carcinoma of the Gallbladder with Calcified Nodal Metastasis Presenting as a Porcelain Gallbladder: A Case Report

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    Porcelain gallbladder is regarded as a risk factor of gallbladder cancer. A porcelain gallbladder with calcified regional lymph nodes was found using computed tomography (CT) and magnetic resonance imaging (MRI) in a 43-year-old man who presented with nausea, vomiting, and abdominal pain. His cholecystectomy specimen showed diffuse wall thickening and contained small gallstones. Histological examination revealed diffuse infiltrative adenocarcinoma with extensive intratumoral calcification (calcified carcinoma). The majority of the calcified material was located within or replaced the tumor glands, and was not found in the stroma. A lymph node was totally replaced with a calcified metastatic adenocarcinoma. To the best of our knowledge, only one case of calcified lymph node metastasis from a calcified carcinoma of the gallbladder has been previously reported in the literature. We herein add a case of calcified carcinoma of the gallbladder with calcified lymph node metastasis, presenting as a porcelain gallbladder on CT and MRI
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