1,174 research outputs found
Design of Direct and Indirect Wind Energy Harvest Systems
-Developing wind energy by using wind collector and
electroactive materials are proposed and investigated in this
article. Two systems will be considered to harvest energy:
direct and indirect system. In direct system, wind induced
drag force directly blow and vibrate the electroactive
materials in the duct for generating electricity. Wind flowguided
mechanism is designed to collect arbitrarily blowing
wind in environment and guide the flow direction
perpendicular to the cross section of the nozzle as much as
possible so that more uniform velocity distribution profile is
achieved. Nozzle accelerator is designed for the purpose of
increasing wind velocity. Indirect system uses gear as
additional mechanism to impact and vibrate the electroactive
materials. Two types of indirect system integrating the wind
collector with fan and roof turbine ventilator to impact and
vibrate electroactive materials are proposed
Analysis and Design of Roof Turbine Ventilator for Wind Energy Harvest
Harvesting energy using roof turbine ventilator and
electroactive material has been investigated to verify its
performance. Since electric power gained from a single piece of
regular size is usually small, auxiliary device to vibrate
multiple pieces of electroactive materials in order to harvest
more power is required. In this paper, an attempt of using the
developed nozzle wind collector associated with the popular
roof turbine ventilator employed with gear mechanism to
impact and vibrate a group of electroactive material to
generate electricity is proposed. Number of blade and blade
angle of the roof turbine ventilator are influential to the
effectiveness of wind collection. Also, number of electroactive
material employed on the turbine ventilator under the wind
speed in environment eventually determines the efficiency of
wind harvest. A simple model is derived to estimate the
minimum driving force from the wind power that needs to
overcome the inertia of the turbine ventilator mechanism and
the electromechanical energy conversion of electroactive
materials. Wind drag force is calculated by using CFD is
assumed to provide such driving force. Various combinations
of the blade angle, number of blade and electroactive material
actuators are investigated in simulations. Optimum design
concerning the environment wind resource and configuration
of turbine ventilator is discussed. According to several case
studies, a few of design trends is addressed for better efficiency
of energy harvest. Since multiple electroactive materials are
employed, circuitry design with parallel input sources is
implemented to sum up the current and integrate the power
IGF-1/IGFBP-1 increases blastocyst formation and total blastocyst cell number in mouse embryo culture and facilitates the establishment of a stem-cell line
BACKGROUND: Apoptosis occurs frequently for blastocysts cultured in vitro, where conditions are suboptimal to those found in the natural environment. Insulin-like growth factor-1 (IGF-1) plays an important role in preventing apoptosis in the early development of the embryo, as well as in the progressive regulation of organ development. We hypothesize that IGF-1 and its dephosphorylated binding protein (IGFBP-1) may be able to improve embryo culture with an associated reduced cell death, and that the resultant increase in the total cell number of the embryo could increase the chances of establishing an embryonic stem-cell line. RESULTS: In vivo fertilized zygotes were cultured in medium containing supplementary IGF-1, or IGFBP-1/IGF-1. The stages of the resultant embryos were evaluated at noon on day five post-hCG injection. The extent of apoptosis and necrosis was evaluated using Annexin V and propidium iodine staining under fluorescent microscopy. The establishment of embryonic stem-cell lines was performed using the hatching blastocysts that were cultured in the presence of IGF-1 or IGFBP-1/IGF-1. The results show that the rate of blastocyst formation in a tissue-culture system in the presence of IGF-1 was 88.7% and IGFBP-1/IGF-1 it was 94.6%, respectively, and that it was significantly greater than the figure for the control group (81.9%). IGFBP-1/IGF-1 also resulted in a higher hatching rate than was the case for the control group (68.8% vs. 48.6% respectively). IGF-1 also increased the number of Annexin V-free and propidium iodine-free blastocysts in culture (86.8% vs. 75.9% respectively). Total cell number of blastocyst in culture was increased by 18.9% for those examples cultured with dephosphorylated IGFBP-1/IGF-1. For subsequent stem-cell culture, the chances of the successful establishment of a stem-cell line was increased for the IGF-1 and IGFBP-1/IGF-1 groups (IGF-1 vs. IGFBP-1/IGF-1 vs. control: 45.8% vs. 59.6% vs. 27.3% respectively). CONCLUSION: IGF-1 or dephosphorylated IGFBP-1/IGF-1 supplement does result in an anti-apoptotic effect for early embryo development in culture, with a subsequent increased total cell number resulting from cell culture. The effect is beneficial for the later establishment of a stem-cell line
Rapid detection of epidermal growth factor receptor mutations with multiplex PCR and primer extension in lung cancer
Epidermal growth factor receptor (EGFR) kinase domain mutations hyperactivate the kinase and confer kinase addiction of the non-small-cell lung cancer (NSCLC) tumor cells. Almost all of these mutations are located within exons 18-21. The -216 single nucleotide polymorphism in the promoter region is associated with increased EGFR production. We present a method for detecting these common mutations in 81 cases of NSCLC. The protocol is based on the multiplex amplification of promoter region and exons 18-21 of the EGFR genes in a single tube, followed by primer extension of the PCR products using various sizes of primers to detect base changes at -216 promoter region and codons 719, 746-750, 790, 858 of the EGFR gene. We compared the results with that from direct sequencing for detecting EGFR mutations in 81 cases of NSCLC. The two methods identified the same 26 mutations, but our method is superior to direct sequencing in terms of the amount of work and time required. We presented a simple and fast method to detect mutations of EGFR genes in NSCLC
InGaN-based light-emitting diodes with an embedded conical air-voids structure
The conical air-void structure of an InGaN light-emitting diode (LEDs) was formed at the GaN/sapphire interface to increase the light extraction efficiency. The fabrication process of the conical air-void structure consisted of a dry process and a crystallographic wet etching process on an undoped GaN layer, followed by a re-growth process for the InGaN LED structure. A higher light output power (1.54 times) and a small divergent angle (120o) were observed, at a 20mA operation current, on the treated LED structure when compared to a standard LED without the conical air-void structure. In this electroluminescence spectrum, the emission intensity and the peak wavelength varied periodically by corresponding to the conical air-void patterns that were measured through a 100nm-optical-aperture fiber probe. The conical air-void structure reduced the compressed strain at the GaN/sapphire interface by inducing the wavelength blueshift phenomenon and the higher internal quantum efficiency of the photoluminescence spectra for the treated LED structure
Structural and cognitive deficits in chronic carbon monoxide intoxication: a voxel-based morphometry study
BACKGROUND: Patients with carbon monoxide (CO) intoxication may develop ongoing neurological and psychiatric symptoms that ebb and flow, a condition often called delayed encephalopathy (DE). The association between morphologic changes in the brain and neuropsychological deficits in DE is poorly understood. METHODS: Magnetic resonance imaging and neuropsychological tests were conducted on 11 CO patients with DE, 11 patients without DE, and 15 age-, sex-, and education-matched healthy subjects. Differences in gray matter volume (GMV) between the subgroups were assessed and further correlated with diminished cognitive functioning. RESULTS: As a group, the patients had lower regional GMV compared to controls in the following regions: basal ganglia, left claustrum, right amygdala, left hippocampus, parietal lobes, and left frontal lobe. The reduced GMV in the bilateral basal ganglia, left post-central gyrus, and left hippocampus correlated with decreased perceptual organization and processing speed function. Those CO patients characterized by DE patients had a lower GMV in the left anterior cingulate and right amygdala, as well as lower levels of cognitive function, than the non-DE patients. CONCLUSIONS: Patients with CO intoxication in the chronic stage showed a worse cognitive and morphologic outcome, especially those with DE. This study provides additional evidence of gray matter structural abnormalities in the pathophysiology of DE in chronic CO intoxicated patients
Seabed gas emissions and submarine landslides off SW Taiwan
Methane emissions out of the seabed could seriously affect Earthâs climate and are usually associated with the dissociation of gas hydrates stored in marine sediments on the continental margins. Spatially, gas emissions out of the seafloor are not evenly distributed in continental margins. Gas emissions out of the seabed generally occur through submarine mud volcanoes and gas seeps. To understand the seabed gas emissions off SW Taiwan, we investigate the distributions of active submarine mud volcanoes, gas seeps, and gas plumes off SW Taiwan. We examine all of the available sub-bottom profiler and EK echo sounder data. We identified 19 submarine mud volcanoes, 220 gas seeps, and 295 gas plumes. The gas emissions are generally distributed at the crests of mud diapiric ridges. Most of the active mud volcanoes and gas seeps cluster at the KASMVG (Kaoping submarine mud volcanoes group) area. We speculate that the intensive mud volcanism and gas seepage at the KASMVG area are ascribed to submarine channel erosion along the continental slope base. The erosion causes a deep V-shaped channel and a steep BSR (Bottom-Simulating Reflector) slope curve across the continental margin. The upward migration rate of free gas beneath the BSR is thus increased and intensifies mud volcanism and gas seepage at the KASMVG area. The gas seeps can reduce the slope stability and generate small-scale slides. The development of mud volcanoes in an area could effectively disturb the seabed morphology so that large-scale submarine landslides cannot easily happen
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