8,965 research outputs found
Predictive Control of Cascaded H-Bridge Converters under Unbalanced Power Generation
© 1982-2012 IEEE. This paper presents a predictive control strategy for grid-connected cascaded H-bridge (CHB) converters under unbalanced power generation among each converter phase. The proposed controller belongs to the finite-control-set model predictive control (FCS-MPC) family and is designed to extract unbalanced power from each CHB converter phase while providing balanced power to the grid. The key novelty of this strategy lies in the way the unbalanced power generation among the phases is explicitly considered into the optimal control problem. Power balance is achieved by enforcing the CHB converter to work with a suitable zero-sequence voltage component. The proposed predictive controller is directly formulated in the original abc-framework to account for the common-mode voltage. Simulation and experimental results are provided to verify the effectiveness of the proposed FCS-MPC strategy
Predictive Control algorithm to achieve power balance of Cascaded H-Bridge converters
© 2015 IEEE. This work proposes a Model Predictive Control (MPC) strategy for Cascaded H-Bridge (CHB) converters under unbalanced power generation among each converter phase. Therefore, the control target is to extract unbalanced power from the dc-sources while providing balanced power to the grid. The key novelty of this proposal lies in the way the unbalanced power generation issue is explicitly considered into the optimal control problem. The power balance is achieved by enforcing the CHB to work with a suitable zero voltage components. Thus, to account for the common-mode voltage, the proposed MPC is directly formulated in the original abc-framework. To verify the effectiveness of this proposal, simulation results of the proposed MPC governing a five-level CHB converter are provided
PTEN mutations are common in sporadic microsatellite stable colorectal cancer
The tumour suppressor gene PTEN, located at chromosome sub-band 10q23.3, encodes a dual-specificity phosphatase that negatively regulates the phosphatidylinositol 3′-kinase (PI3 K)/Akt-dependent cellular survival pathway. PTEN is frequently inactivated in many tumour types including glioblastoma, prostate and endometrial cancers. While initial studies reported that PTEN gene mutations were rare in colorectal cancer, more recent reports have shown an approximate 18% incidence of somatic PTEN mutations in colorectal tumours exhibiting microsatellite instability (MSI+). To verify the role of this gene in colorectal tumorigenesis, we analysed paired normal and tumour DNA from 41 unselected primary sporadic colorectal cancers for PTEN inactivation by mutation and/or allelic loss. We now report PTEN gene mutations in 19.5% (8/41) of tumours and allele loss, including all or part of the PTEN gene, in a further 17% (7/41) of the cases. Both PTEN alleles were affected in over half (9/15) of these cases showing PTEN genetic abnormalities. Using immunohistochemistry, we have further shown that all tumours harbouring PTEN alterations have either reduced or absent PTEN expression and this correlated strongly with later clinical stage of tumour at presentation (P = 0.02). In contrast to previous reports, all but one of the tumours with PTEN gene mutations were microsatellite stable (MSI-), suggesting that PTEN is involved in a distinct pathway of colorectal tumorigenesis that is separate from the pathway of mismatch repair deficiency. This work therefore establishes the importance of PTEN in primary sporadic colorectal cancer
Seeing two faces together: preference formation in humans and rhesus macaques
Humans, great apes and old world monkeys show selective attention to faces depending on conspecificity, familiarity, and social status supporting the view that primates share similar face processing mechanisms. Although many studies have been done on face scanning strategy in monkeys and humans, the mechanisms influencing viewing preference have received little attention. To determine how face categories influence viewing preference in humans and rhesus macaques (Macaca mulatta), we performed two eye-tracking experiments using a visual preference task whereby pairs of faces from different species were presented simultaneously. The results indicated that viewing time was significantly influenced by the pairing of the face categories. Humans showed a strong bias towards an own-race face in an Asian–Caucasian condition. Rhesus macaques directed more attention towards non-human primate faces when they were paired with human faces, regardless of the species. When rhesus faces were paired with faces from Barbary macaques
(Macaca sylvanus) or chimpanzees (Pan troglodytes), the novel species’ faces attracted more attention. These results
indicate that monkeys’ viewing preferences, as assessed by a visual preference task, are modulated by several factors,
species and dominance being the most influential
InvS Coordinates Expression of PrgH and FimZ and Is Required for Invasion of Epithelial Cells by Salmonella enterica serovar Typhimurium
ABSTRACT
Deep sequencing has revolutionized our understanding of the bacterial RNA world and has facilitated the identification of 280 small RNAs (sRNAs) in
Salmonella
. Despite the suspicions that sRNAs may play important roles in
Salmonella
pathogenesis, the functions of most sRNAs remain unknown. To advance our understanding of RNA biology in
Salmonella
virulence, we searched for sRNAs required for bacterial invasion into nonphagocytic cells. After screening 75 sRNAs, we discovered that the ablation of InvS caused a significant decrease of
Salmonella
invasion into epithelial cells. A proteomic analysis showed that InvS modulated the levels of several type III secreted
Salmonella
proteins. The level of PrgH, a type III secretion apparatus protein, was significantly lower in the absence of InvS, consistent with the known roles of PrgH in effector secretion and bacterial invasion. We discovered that InvS modulates
fimZ
expression and hence flagellar gene expression and motility. We propose that InvS coordinates the increase of PrgH and decrease in FimZ that promote efficient
Salmonella
invasion into nonphagocytic cells.
IMPORTANCE
Salmonellosis continues to be the most common foodborne infection reported by the CDC in the United States. Central to
Salmonella
pathogenesis is the ability to invade nonphagocytic cells and to replicate inside host cells. Invasion genes are known to be regulated by protein transcriptional networks, but little is known about the role played by small RNAs (sRNAs) in this process. We have identified a novel sRNA, InvS, that is involved in
Salmonella
invasion. Our result will likely provide an opportunity to better understand the fundamental question of how
Salmonella
regulates invasion gene expression and may inform strategies for therapeutic intervention.
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Control of Emi2 activity and stability through Mos-mediated recruitment of PP2A.
Before fertilization, vertebrate eggs are arrested in meiosis II by cytostatic factor (CSF), which holds the anaphase-promoting complex (APC) in an inactive state. It was recently reported that Mos, an integral component of CSF, acts in part by promoting the Rsk-mediated phosphorylation of the APC inhibitor Emi2/Erp1. We report here that Rsk phosphorylation of Emi2 promotes its interaction with the protein phosphatase PP2A. Emi2 residues adjacent to the Rsk phosphorylation site were important for PP2A binding. An Emi2 mutant that retained Rsk phosphorylation but lacked PP2A binding could not be modulated by Mos. PP2A bound to Emi2 acted on two distinct clusters of sites phosphorylated by Cdc2, one responsible for modulating its stability during CSF arrest and one that controls binding to the APC. These findings provide a molecular mechanism for Mos action in promoting CSF arrest and also define an unusual mechanism, whereby protein phosphorylation recruits a phosphatase for dephosphorylation of distinct sites phosphorylated by another kinase
Design and Testing of Cesium Atomic Concentration Detection System Based on TDLAS
In order to better build the Neutral Beam Injector with Negative Ion Source
(NNBI), the pre-research on key technologies has been carried out for the
Comprehensive Research Facility for Fusion Technology (CRAFT). Cesium seeding
into negative-ion sources is a prerequisite to obtain the required negative
hydrogen ion. The performance of ion source largely depends on the cesium
conditions in the source. It is very necessary to quantitatively measure the
amount of cesium in the source during the plasma on and off periods (vacuum
stage). This article uses the absorption peak of cesium atoms near 852.1nm to
build a cesium atom concentration detection system based on Tunable Diode Laser
Absorption Spectroscopy (TDLAS) technology. The test experiment based on the
cesium cell is carried out, obtained the variation curve of cesium
concentration at different temperatures. The experimental results indicate
that: the system detection range is within 5*10E6-2.5*10E7 pieces/cm3 and the
system resolution better than 1*10E6 pieces/cm3.Comment: 8 pages,7 figures, the 20th International Symposium on Laser-Aided
Plasma Diagnostic
Analysis of energy expenditure in diet-induced obese rats
Development of obesity in animals is affected by energy intake, dietary composition, and metabolism. Useful models for studying this metabolic problem are Sprague-Dawley rats fed low-fat (LF) or high-fat (HF) diets beginning at 28 days of age. Through experimental design, their dietary intakes of energy, protein, vitamins, and minerals per kg body weight (BW) do not differ in order to eliminate confounding factors in data interpretation. The 24-h energy expenditure of rats is measured using indirect calorimetry. A regression model is constructed to accurately predict BW gain based on diet, initial BW gain, and the principal component scores of respiratory quotient and heat production. Time-course data on metabolism (including energy expenditure) are analyzed using a mixed effect model that fits both fixed and random effects. Cluster analysis is employed to classify rats as normal-weight or obese. HF-fed rats are heavier than LF-fed rats, but rates of their heat production per kg non-fat mass do not differ. We conclude that metabolic conversion of dietary lipids into body fat primarily contributes to obesity in HF-fed rats
Psychiatric Aspects of the Treatment of Mild to Moderate Facial Acne
The improvement of acne appears to be associated with decreased depression and anxiety and greater satisfaction with aspects of body image that are generally unrelated to the appearance of the skin, ie, body shape and weight. The latter emphasizes the profound effect of the appearance of the skin upon the patient's overall body image. Our preliminary findings underline the need for larger controlled studies of psychosomatic factors among patients with mild to moderate acne.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65635/1/j.1365-4362.1990.tb03777.x.pd
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