135 research outputs found
Two-Stage Inverter Based on Combination of High Gain DC-DC Converter and Five-Level Inverter for PV-Battery Energy Conversion
This paper proposes a new two-stage inverter based on transformer-less high gain DC-DC converter for energy conversion of a photovoltaic system. The designed system consists of a high gain DC-DC converter cascaded with a three-phase inverter. The proposed DC-DC converter has a simple structure, and it has one switch in its structure. The output voltage of the DC-DC converter supplies DC source for the inverter part of the multi-stage inverter. The advanced two-stage inverter sample was fabricated, then the findings of the acquired simulation and hardware warranted the configuration applicability. Finally, the MATLAB/SIMULINK is employed for the simulation of PV-battery system. The obtained results revel that the proposed power conversion system effectively chases the load and generation fluctuations and also properly handles the power mismatches in PV-battery system
Analysis of Switched Inductor Three-level DC/DC Converter
A non-isolated DC/DC converter with high transfer gain is proposed in this paper. The presented converter consists of the switched inductor and three-level converters. The DC/DC power converter is three-level boost converter to convert the output voltage of the DC source into two voltage sources. The main advantages of DC/DC converter are using low voltage semiconductors and high gain voltage. The steady-state operation of the suggested converter is analyzed. A prototype is developed and tested to verify the performance of the proposed converter. To sum up, the MATLAB simulation results and the experimental results have transparently approved high efficiency of proposed converter as well as its feasibility
Two Inputs Five-Level Quasi-Z-Source Inverter
This paper combines quasi-Z-source into a typical five-level inverter, which includes two dc voltage sources, two quasi-Z-sources and five switching devices. In this structure, the output voltage amplitude is not limited to dc voltage source and it can be increased by quasi-Z-source. Besides, due to nature of Z-source families, this new structure is reliable and higher efficiency. Also, in this inverter, two quasi-Z-networks can be controlled independently. This paper also proposes new switching algorithms for proposed five-level dual quasi-Z-Source inverter based on pulse width modulation (PWM) and selective harmonic elimination method (SHEM) algorithms .The performance of proposed inverter and switching algorithm are validated with simulation results using MATLAB/SIMULINK software and experimental results based PCI-1716 data acquisition system
An Isolated Off-Line High Power Factor Electrolytic Capacitor-Less LED Driver with Pulsating Output Current
One of the most efficient lighting technology is based on light-emitting diodes (LEDs). Common LED drivers with AC-input (50-60Hz) usually require a bulk electrolytic capacitor to decrease low-frequency ripple in the output. However, the critical element that limits the lifespan of the LED driver is the electrolytic capacitor. An isolated off-line LED driver is proposed in this paper, in which the required output capacitance is reduced so that the electrolytic capacitor can be omitted from the driver structure. The driver’s configuration and controlling method provide a high input power factor. Just a single switch and therefore a single controlling IC have been used in the proposed structure. The input power factor correction is implemented utilizing a boost-based method, and a novel structure is introduced for dc/dc conversion section. Power factor correction and dc/dc conversion are performed employing a simplistic and single controlling system. The output current feeding the LEDs is a high frequency pulsating current. Calculations, simulations and experimental waveforms of a laboratory prototype are presented to confirm the validity of the proposed driver
Estimation of radiation dose-reduction factor for cerium oxide nanoparticles in MRC-5 human lung fibroblastic cells and MCF-7 breast-cancer cells
In the current study, radiation dose-reduction factor (DRF) of nanoceria or cerium oxide nanoparticles (CONPs) in MRC-5 Human Lung Fibroblastic Cells and MCF-7 Breast-Cancer Cells was estimated. Characterization of CONPs was determined using scanner electron microscope (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM) and spectrophotometer. Then, six plans were designed with different radiation dose values on planning target value. The obtained MRC-5 and MCF-7 cells were treated with non-toxic concentrations of CONPs and then exposed. Finally, cell viability () of the cell lines was determined using MTT assay. The findings showed that CONPs have no significant radioprotective effect against 10 cGy radiation dose value. Nevertheless, 70 μM CONPs resulted in a significant radioprotection against 100, 200, 300, 400 and 500 cGy radiation dose values compared with the control group in MRC-5 cells. For all radiation dose values, mean cell viability () of MCF-7 had not increased significantly at the presence of nanoceria compared with control group. According to the findings, it was revealed that the use of CONPs have a significant radioprotective effect on normal lung cells, while they do not provide any protection for MCF-7 cancer cells. These properties can help to increase therapeutic ratio of radiotherapy. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group
Analysis of microRNA signatures using size-coded ligation-mediated PCR
The expression pattern and regulatory functions of microRNAs (miRNAs) are intensively investigated in various tissues, cell types and disorders. Differential miRNA expression signatures have been revealed in healthy and unhealthy tissues using high-throughput profiling methods. For further analyses of miRNA signatures in biological samples, we describe here a simple and efficient method to detect multiple miRNAs simultaneously in total RNA. The size-coded ligation-mediated polymerase chain reaction (SL-PCR) method is based on size-coded DNA probe hybridization in solution, followed-by ligation, PCR amplification and gel fractionation. The new method shows quantitative and specific detection of miRNAs. We profiled miRNAs of the let-7 family in a number of organisms, tissues and cell types and the results correspond with their incidence in the genome and reported expression levels. Finally, SL-PCR detected let-7 expression changes in human embryonic stem cells as they differentiate to neuron and also in young and aged mice brain and bone marrow. We conclude that the method can efficiently reveal miRNA signatures in a range of biological samples
Quantitative proteome landscape of the NCI-60 cancer cell lines
Here we describe a proteomic data resource for the NCI-60 cell lines generated by pressure cycling technology and SWATH mass spectrometry. We developed the DIA-expert software to curate and visualize the SWATH data, leading to reproducible detection of over 3,100 SwissProt proteotypic proteins and systematic quantification of pathway activities. Stoichiometric relationships of interacting proteins for DNA replication, repair, the chromatin remodeling NuRD complex, β-catenin, RNA metabolism, and prefoldins are more evident than that at the mRNA level. The data are available in CellMiner (discover.nci.nih.gov/cellminercdb and discover.nci.nih.gov/cellminer), allowing casual users to test hypotheses and perform integrative, cross-database analyses of multi-omic drug response correlations for over 20,000 drugs. We demonstrate the value of proteome data in predicting drug response for over 240 clinically relevant chemotherapeutic and targeted therapies. In summary, we present a novel proteome resource for the NCI-60, together with relevant software tools, and demonstrate the benefit of proteome analyses
The pancreas anatomy conditions the origin and properties of resident macrophages
We examine the features, origin, turnover, and gene expression of pancreatic macrophages under steady state. The data distinguish macrophages within distinct intrapancreatic microenvironments and suggest how macrophage phenotype is imprinted by the local milieu. Macrophages in islets of Langerhans and in the interacinar stroma are distinct in origin and phenotypic properties. In islets, macrophages are the only myeloid cells: they derive from definitive hematopoiesis, exchange to a minimum with blood cells, have a low level of self-replication, and depend on CSF-1. They express Il1b and Tnfa transcripts, indicating classical activation, M1, under steady state. The interacinar stroma contains two macrophage subsets. One is derived from primitive hematopoiesis, with no interchange by blood cells and alternative, M2, activation profile, whereas the second is derived from definitive hematopoiesis and exchanges with circulating myeloid cells but also shows an alternative activation profile. Complete replacement of islet and stromal macrophages by donor stem cells occurred after lethal irradiation with identical profiles as observed under steady state. The extraordinary plasticity of macrophages within the pancreatic organ and the distinct features imprinted by their anatomical localization sets the base for examining these cells in pathological conditions
Pleural cancer mortality in Spain: time-trends and updating of predictions up to 2020
Background
A total of 2,514,346 metric tons (Mt) of asbestos were imported into Spain from 1906 until the ban on asbestos in 2002. Our objective was to study pleural cancer mortality trends as an indicator of mesothelioma mortality and update mortality predictions for the periods 2011–2015 and 2016–2020 in Spain.Methods
Log-linear Poisson models were fitted to study the effect of age, period of death and birth cohort (APC) on mortality trends. Change points in cohort- and period-effect curvatures were assessed using segmented regression. Fractional power-link APC models were used to predict mortality until 2020. In addition, an alternative model based on national asbestos consumption figures was also used to perform long-term predictions.Results
Pleural cancer deaths increased across the study period, rising from 491 in 1976–1980 to 1,249 in 2006–2010. Predictions for the five-year period 2016–2020 indicated a total of 1,319 pleural cancer deaths (264 deaths/year). Forecasts up to 2020 indicated that this increase would continue, though the age-adjusted rates showed a levelling-off in male mortality from 2001 to 2005, corresponding to the lower risk in post-1960 generations. Among women, rates were lower and the mortality trend was also different, indicating that occupational exposure was possibly the single factor having most influence on pleural cancer mortality.Conclusion
The cancer mortality-related consequences of human exposure to asbestos are set to persist and remain in evidence until the last surviving members of the exposed cohorts have disappeared. It can thus be assumed that occupationally-related deaths due to pleural mesothelioma will continue to occur in Spain until at least 2040.The study was partially supported by a research grant from the Spanish Health Research Fund (FIS PI11/00871) and the HAR2009-07543 project of the Ministry of Science and Innovation. The Department of Labour of the Government of Catalonia provided the asbestos consumption data
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