High-Efficiency Isolated Photovoltaic Microinverter Using Wide-Band Gap Switches for Standalone and Grid-Tied Applications

An isolated photovoltaic micro-inverter for standalone and grid-tied applications is designed and implemented to achieve high efficiency. System configuration and design considerations, including the proposed active-clamp forward-flyback resonant converter for the DC-DC stage and a dual-frequency full-bridge inverter for the DC-AC stage, are analyzed and discussed. A prototype microinverter system is built and tested. Experimental results verify the feasibility of the proposed system, which achieves 95% power conversion efficiency at full load

Comparison of power control schemes for relay sensor networks

[[abstract]]Three power control schemes for the space-time coded amplify-and-forward (AF) relaying scheme targeting at wireless sensor network applications are examined and compared. The opportunistic scheme performs the best by considering the signal-to-noise-ratio (SNR) of the received signal. However, if the power for the relay is limited, the performance of the opportunistic scheme degrades due to the loss of active relay nodes that have better channel conditions. Since the battery lifetime of nodes for wireless sensor networks is limited and the loss of relay nodes is critical to system performance, we propose an SNR-constrained power reduction scheme to prolong the relay lifetime for the opportunistic scheme. It is demonstrated by computer simulation that the opportunistic scheme with SNR-constrained power reduction is power efficient and the relay lifetime of dense relay networks can be significantly prolonged. © 2007 IEEE.[[fileno]]2030137030003[[department]]電機工程學

Sample entropy analysis of EEG signals via artificial neural networks to model patients' consciousness level based on anesthesiologists experience.

Electroencephalogram (EEG) signals, as it can express the human brain's activities and reflect awareness, have been widely used in many research and medical equipment to build a noninvasive monitoring index to the depth of anesthesia (DOA). Bispectral (BIS) index monitor is one of the famous and important indicators for anesthesiologists primarily using EEG signals when assessing the DOA. In this study, an attempt is made to build a new indicator using EEG signals to provide a more valuable reference to the DOA for clinical researchers. The EEG signals are collected from patients under anesthetic surgery which are filtered using multivariate empirical mode decomposition (MEMD) method and analyzed using sample entropy (SampEn) analysis. The calculated signals from SampEn are utilized to train an artificial neural network (ANN) model through using expert assessment of consciousness level (EACL) which is assessed by experienced anesthesiologists as the target to train, validate, and test the ANN. The results that are achieved using the proposed system are compared to BIS index. The proposed system results show that it is not only having similar characteristic to BIS index but also more close to experienced anesthesiologists which illustrates the consciousness level and reflects the DOA successfully.This research is supported by the Center forDynamical Biomarkers and Translational Medicine, National Central University, Taiwan, which is sponsored by Ministry of Science and Technology (Grant no. MOST103-2911-I-008-001). Also, it is supported by National Chung-Shan Institute of Science & Technology in Taiwan (Grant nos. CSIST-095-V301 and CSIST-095-V302)

Genotoxicity Assessment of Multispecies Probiotics Using Reverse Mutation, Mammalian Chromosomal Aberration, and Rodent Micronucleus Tests

Genotoxicity assessment is carried out on freeze dried powder of cultured probiotics containing Lactobacillus rhamnosus LCR177, Bifidobacterium adolescentis BA286, and Pediococcus acidilactici PA318. Ames tests, in vitro mammalian chromosome aberration assay, and micronucleus tests in mouse peripheral blood are performed. For 5 strains of Salmonella Typhimurium, the Ames tests show no increased reverse mutation upon exposure to the test substance. In CHO cells, the frequency of chromosome aberration does not increase in responding to the treatment of probiotics. Likewise, the frequency of micronucleated reticulocytes in probiotics-fed mice is indistinguishable from that in the negative control group. Taken together, the toxicity assessment studies suggest that the multispecies probiotic mixture does not have mutagenic effects on various organisms

T Oligo-Primed Polymerase Chain Reaction (TOP-PCR): A Robust Method for the Amplification of Minute DNA Fragments in Body Fluids.

Body fluid DNA sequencing is a powerful noninvasive approach for the diagnosis of genetic defects, infectious agents and diseases. The success relies on the quantity and quality of the DNA samples. However, numerous clinical samples are either at low quantity or of poor quality due to various reasons. To overcome these problems, we have developed T oligo-primed polymerase chain reaction (TOP-PCR) for full-length nonselective amplification of minute quantity of DNA fragments. TOP-PCR adopts homogeneous "half adaptor" (HA), generated by annealing P oligo (carrying a phosphate group at the 5' end) and T oligo (carrying a T-tail at the 3' end), for efficient ligation to target DNA and subsequent PCR amplification primed by the T oligo alone. Using DNA samples from body fluids, we demonstrate that TOP-PCR recovers minute DNA fragments and maintains the DNA size profile, while enhancing the major molecular populations. Our results also showed that TOP-PCR is a superior method for detecting apoptosis and outperforms the method adopted by Illumina for DNA amplification

Emergence in Taiwan of novel imipenem-resistant Acinetobacter baumannii ST455 causing bloodstream infection in critical patients

BackgroundAcinetobacter baumannii is one of the most important noscomial pathogens worldwide. The study aimed to use multilocus sequence typing (MLST) for epidemiological surveillance of A. baumannii isolates in Taiwan and analyze the clinical presentations and patients' outcomes.MethodsMLST according to both Bartual's PubMLST and Pasteur's MLST schemes was applied to characterize bloodstream imipenem-resistant A. baumannii (IRAB) infection in intensive care units in a medical center. A total of 39 clinical IRAB bloodstream isolates in 2010 were enrolled. We also collected 13 imipenem-susceptible A. baumannii bloodstream isolates and 30 clinical sputum isolates (24 IRAB and 6 imipenem-susceptible A. baumannii) for comparison. Clinical presentations and outcome of the patients were analyzed.ResultsWe found that infection by ST455B/ST2P and inappropriate initial therapy were statistically significant risk factors for mortality. More than one third of the IRAB isolates belonged to ST455B/ST2P. Most ST455B/ST2P (80%) carried ISAba1–blaOXA-23, including 10 (66.7%) with Tn2006 (ISAba1–blaOXA-23–ISAba1) in an AbaR4-type resistance island. ST455B/ST2P appears to evolve from ST208B/ST2P of clonal complex (CC) 92B/CC2P. In this hospital-based study, A. baumannii ST455 accounted for 38.5% of IRAB bacteremia, with a high mortality of 86.7%. Approximately 85% of ST455B/ST2P bacteremia had a primary source of ventilation-associated pneumonia.ConclusionWe report the emergence in Taiwan of IRAB ST455B/ST2P, which is the current predominant clone of IRAB in our hospital and has been causing bacteremia with high mortality in critical patients

Opening the Box: Survey of High Power Density Inverter Techniques From the Little Box Challenge

The Little Box Challenge (LBC) was a competition sponsored by Google and the IEEE Power Electronics Society in 2014-2015, where participants were challenged to design a high power-density single-phase 2 kVA inverter. This paper surveys the designs from eight different participating teams, including academic grant awardees, finalists, and the winners. Inverter topologies, power decoupling circuits, and thermal management strategies are overviewed for each team. Wide bandgap switches were heavily utilized in both the inverter and power decoupling circuits, particularly GaN switches. Most teams utilized a full-bridge inverter with some variations and the most common power decoupling strategy was the use of a synchronous buck converter and a power buffering capacitor. One team used a multi-level inverter approach and a number of teams proposed innovative power decoupling topologies. Heat sinks and active cooling systems, many of which were custom made, were crucial for teams to stay within the 50 ??C case temperature limit. The resulting power density of the surveyed teams ranged from 55.8 to 216 W/in3, all of which exceed the 50 W/in3 LBC requirement. This paper surveys the approaches for various teams, shares experimental results from the Taiwan Tech team, and highlights some innovations from the teams that participated in the LBC

EBV-encoded small RNA1 and nonresolving inflammation in rheumatoid arthritis

AbstractRheumatoid arthritis (RA) is a chronic autoimmune disease characterized by perpetuated inflammation in multiple joints. To date, there is no cure for RA, and the causal factor for non-resolving inflammation in RA remains unclear. In this study, we initially observed expression of Epstein–Barr virus-encoded small RNA1 (EBER1) in the synovial tissue of all five patients who showed nonresolving RA inflammation. By contrast, EBER1 was detected in the synovial tissue of only one out of seven patients with advanced osteoarthritis (OA; p < 0.01, Fisher’s exact test). To confirm this finding, we conducted a second study on synovial tissue samples taken from 23 patients with nonresolving RA inflammation and 13 patients with OA. All synovial samples from patients with nonresolving inflammation of RA showed positive expression of EBER1 (23/23, 100%), whereas none of the synovial samples from patients with OA showed expression of EBER1 (0/13, 0%; p < 0.001, by Fisher’s exact test). In vitro, transfection of RA synovial fibroblasts with EBER1 induced the production of interleukin-6. Taken together, these data strongly suggest that nonresolving RA inflammation is strongly related to the presence of EBER1, which might be, at least partially, responsible for synovial fibroblast interleukin-6 production