116 research outputs found
Equal Incremental Cost-Based Optimization Method to Enhance Efficiency for IPOP-Type Converters
Systematic optimization over a wide power range is often achieved through the
combination of modules of different power levels. This paper addresses the
issue of enhancing the efficiency of a multiple module system connected in
parallel during operation and proposes an algorithm based on equal incremental
cost for dynamic load allocation. Initially, a polynomial fitting technique is
employed to fit efficiency test points for individual modules. Subsequently,
the equal incremental cost-based optimization is utilized to formulate an
efficiency optimization and allocation scheme for the multi-module system. A
simulated annealing algorithm is applied to determine the optimal power output
strategy for each module at given total power flow requirement. Finally, a dual
active bridge (DAB) experimental prototype with two
input-parallel-output-parallel (IPOP) configurations is constructed to validate
the effectiveness of the proposed strategy. Experimental results demonstrate
that under the 800W operating condition, the approach in this paper achieves an
efficiency improvement of over 0.74\% by comparison with equal power sharing
between both modules
Anticipation of Uncertain Threat Modulates Subsequent Affective Responses and Covariation Bias
Uncertainty contributes to stress and anxiety-like behaviors by impairing the ability of participants to objectively estimate threat. Our study used the cue-picture paradigm in conjunction with the event-related potential (ERP) technique to explore the temporal dynamics of anticipation for and response to uncertain threat in healthy individuals. This task used two types of cue. While ācertainā cues precisely forecasted the valence of the subsequent pictures (negative or neutral), the valence of pictures following āuncertainā cues was not predictable. ERP data showed that, during anticipation, uncertain cues elicited similar Stimulus-Preceding Negativity (SPN) to certain-negative cues, while both of them elicited larger SPN than certain-neutral cues. During affective processing, uncertainty enlarged the mean amplitude of late positive potential (LPP) for both negative and neutral pictures. Behavioral data showed that participants reported more negative mood ratings of uncertain-neutral pictures relative to certain-neutral pictures and overestimated the probability of negative pictures following uncertain cues. Importantly, the enlarged anticipatory activity evoked by uncertain cues relative to that evoked by certain-neutral cues positively modulated the more negative mood ratings of uncertain-neutral pictures relative to certain-neutral pictures. Further, this more negative mood ratings and the general arousal anticipation during anticipatory stage contributed to the covariation bias. These results can provide a novel insight into understanding the neural mechanism and pathological basis of anxiety
Replication Stress Induces Micronuclei Comprising of Aggregated DNA Double-Strand Breaks
BACKGROUND: Micronuclei (MN) in mammalian cells serve as a reliable biomarker of genomic instability and genotoxic exposure. Elevation of MN is commonly observed in cells bearing intrinsic genomic instability and in normal cells exposed to genotoxic agents. DNA double-strand breaks are marked by phosphorylation of H2AX at serine 139 (Ī³-H2AX). One subclass of MN contains massive and uniform Ī³-H2AX signals. This study tested whether this subclass of MN can be induced by replication stress. PRINCIPAL FINDINGS: We observed that a large proportion of MN, from 20% to nearly 50%, showed uniform staining by antibodies against Ī³-H2AX, a marker of DNA double-strand breaks (DSBs). Such micronuclei were designated as MN-Ī³-H2AX (+). We showed that such MN can be induced by chemicals that are known to cause DNA replication stress and S phase arrest. Hydroxyurea, aphidicolin and thymidine could all significantly induce MN-Ī³-H2AX (+), which were formed during S phase and appeared to be derived from aggregation of DSBs. MN-Ī³-H2AX (-), MN that were devoid of uniform Ī³-H2AX signals, were induced to a lesser extent in terms of fold change. Paclitaxel, which inhibits the disassembly of microtubules, only induced MN-Ī³-H2AX (-). The frequency of MN-Ī³-H2AX (+), but not that of MN-Ī³-H2AX (-), was also significantly increased in cells that experience S phase prolongation due to depletion of cell cycle regulator CUL4B. Depletion of replication protein A1 (RPA1) by RNA interference resulted in an elevation of both MN-Ī³-H2AX (+) and MN-Ī³-H2AX (-). CONCLUSIONS/SIGNIFICANCE: A subclass of MN, MN-Ī³-H2AX (+), can be preferentially induced by replication stress. Classification of MN according to their Ī³-H2AX status may provide a more refined evaluation of intrinsic genomic instabilities and the various environmental genotoxicants
Ab initio identification of transcription start sites in the Rhesus macaque genome by histone modification and RNA-Seq
Rhesus macaque is a widely used primate model organism. Its genome annotations are however still largely comparative computational predictions derived mainly from human genes, which precludes studies on the macaque-specific genes, gene isoforms or their regulations. Here we took advantage of histone H3 lysine 4 trimethylation (H3K4me3)ās ability to mark transcription start sites (TSSs) and the recently developed ChIP-Seq and RNA-Seq technology to survey the transcript structures. We generated 14ā013ā757 sequence tags by H3K4me3 ChIP-Seq and obtained 17ā322ā358 paired end reads for mRNA, and 10ā698ā419 short reads for sRNA from the macaque brain. By integrating these data with genomic sequence features and extending and improving a state-of-the-art TSS prediction algorithm, we ab initio predicted and verified 17ā933 of previously electronically annotated TSSs at 500-bp resolution. We also predicted approximately 10ā000 novel TSSs. These provide an important rich resource for close examination of the species-specific transcript structures and transcription regulations in the Rhesus macaque genome. Our approach exemplifies a relatively inexpensive way to generate a reasonably reliable TSS map for a large genome. It may serve as a guiding example for similar genome annotation efforts targeted at other model organisms
Flow-time minimization for timely data stream processing in UAV-aided mobile edge computing
Unmanned Aerial Vehicle (UAV) has gained increasing attentions by both academic and industrial communities, due to its flexible deployment and efficient line-of-sight communication. Recently, UAVs equipped with base stations have been envisioned as a key technology to provide 5G network services for mobile users. In this paper, we provide timely services on the data streams of mobile users in a UAV-aided Mobile Edge Computing (MEC) network, in which each UAV is equipped with a 5G small-cell base station for communication and data processing. Specifically, we first formulate a flow-time minimization problem by jointly caching services and offloading tasks of mobile users to the UAV-aided MEC with the aim to minimize the flow-time, where the flow-time of a user request is referred to the time duration from the request issuing time point to its completion point, subject to resource and energy capacity on each UAV. We then propose a spatial-temporal learning optimization framework. We also devise an online algorithm with a competitive ratio for the problem based upon the framework, by leveraging the round-robin scheduling and dual fitting techniques. Finally, we evaluate the performance of the proposed algorithms through experimental simulation. The simulation results demonstrated that the proposed algorithms outperform their comparison counterparts, by reducing the flow-time no less than 19% on average
Successful cervicothoracic esophageal stricture treatment with partial sternectomy and a pedicled TAAP flap: A case report
Postoperative benign esophageal anastomotic leakage and stenosis are common complications after esophagectomy. Treatment options for anastomosis stenosis include endoscopic mechanical dilation, dilation-combined steroid injection, incisional therapy, stent placement, and self-bougienage. However, long-segmental cervicothoracic esophageal stenosis and cutaneous fistula are always refractory to conservative treatments and are clinically challenging. When lesions extend well below the thoracic inlet, transthoracic esophagectomy and alimentary canal reconstruction seem to be the common choice but are susceptible to perioperative mortality and donor-site sequelae, especially for patients with poor health conditions. In this report, we present a novel surgical approach for cervicothoracic esophageal stenosis and fistula via partial sternectomy and reconstruction with a pedicled thoracoacromial artery perforator flap. No recurrence or complications occurred throughout 3 months of follow-up. This case study adds new perspectives to the treatment of anastomotic stenosis
Observation of electronic nematicity driven by three-dimensional charge density wave in kagome lattice KVSb
Kagome superconductors AVSb (A = K, Rb, Cs) provide a fertile
playground for studying various intriguing phenomena such as non-trivial band
topology, superconductivity, giant anomalous Hall effect, and charge density
wave (CDW). Remarkably, the recent discovery of symmetric nematic phase
prior to the superconducting state in AVSb has drawn enormous
attention, as the unusual superconductivity might inherit the symmetry of the
nematic phase. Although many efforts have been devoted to resolve the charge
orders using real-space microscopy and transport measurements, the direct
evidence on the rotation symmetry breaking of the electronic structure in the
CDW state from the reciprocal space is still rare. The underlying mechanism is
still ambiguous. Here, utilizing the micron-scale spatially resolved
angle-resolved photoemission spectroscopy, we observed the fingerprint of band
folding in the CDW phase of KVSb, which yet demonstrates the
unconventional unidirectionality, and is indicative of the rotation symmetry
breaking from to . We then pinpointed that the interlayer coupling
between adjacent planes with -phase offset in the 222 CDW
phase would lead to the preferred twofold symmetric electronic structure.
Time-reversal symmetry is further broken at temperatures below 40 K as
characterized by giant anomalous Hall effect triggered by weak magnetic fields.
These rarely observed unidirectional back-folded bands with time-reversal
symmetry breaking in KVSb may provide important insights into its
peculiar charge order and superconductivity
Ab initio identification of transcription start sites in the Rhesus macaque genome by histone modification and RNA-Seq
Rhesus macaque is a widely used primate model organism. Its genome annotations are however still largely comparative computational predictions derived mainly from human genes, which precludes studies on the macaque-specific genes, gene isoforms or their regulations. Here we took advantage of histone H3 lysine 4 trimethylation (H3K4me3)ās ability to mark transcription start sites (TSSs) and the recently developed ChIP-Seq and RNA-Seq technology to survey the transcript structures. We generated 14ā013ā757 sequence tags by H3K4me3 ChIP-Seq and obtained 17ā322ā358 paired end reads for mRNA, and 10ā698ā419 short reads for sRNA from the macaque brain. By integrating these data with genomic sequence features and extending and improving a state-of-the-art TSS prediction algorithm, we ab initio predicted and verified 17ā933 of previously electronically annotated TSSs at 500-bp resolution. We also predicted approximately 10ā000 novel TSSs. These provide an important rich resource for close examination of the species-specific transcript structures and transcription regulations in the Rhesus macaque genome. Our approach exemplifies a relatively inexpensive way to generate a reasonably reliable TSS map for a large genome. It may serve as a guiding example for similar genome annotation efforts targeted at other model organisms
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A Phytophthora sojae effector suppresses endoplasmic reticulum stress-mediated immunity by stabilizing plant Binding immunoglobulin Proteins
Phytophthora pathogens secrete an array of specific effector proteins to manipulate host innate immunity to promote pathogen colonization. However, little is known about the host targets of effectors and the specific mechanisms by which effectors increase susceptibility. Here we report that the soybean pathogen Phytophthora sojae uses an essential effector PsAvh262 to stabilize endoplasmic reticulum (ER)-luminal binding immunoglobulin proteins (BiPs), which act as negative regulators of plant resistance to Phytophthora. By stabilizing BiPs, PsAvh262 suppresses ER stress-triggered cell death and facilitates Phytophthora infection. The direct targeting of ER stress regulators may represent a common mechanism of host manipulation by microbes.This is the publisherās final pdf. The published article is copyrighted by the author(s) and published by Nature Publishing Group. The published article can be found at: http://www.nature.com/ncomms/index.htm
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