Three-phase boost-stage coupled current source inverter concept and its space vector modulation

The current source inverter (CSI) is essentially a converter with inherent boost capability and has been preliminarily applied in the field of renewable energy generation systems. However, conventional CSIs are mostly operated independently. Several existing multilevel CSI topologies entirely rely on parallel combinations, which seems to be not very suitable for capacity expansion. To solve this issue, this paper proposes a concept of three-phase boost-stage coupled current source inverter (BSC-CSI) through the duality principle, which can output multi-level currents with a reduced number of switches as well as hardware costs. Compared with the state-of-the-art CSIs, the proposed BSC-CSI can notably simplify the implementation of the multi-level modulation scheme and meanwhile ensure the power devices switch under lower current stress. To further take full advantage of the modularity and scalability, the BSC-CSI can be constructed by hybrid using silicon-carbide (SiC) and silicon (Si) based semiconductor switches for improving efficiency. The experimental results have verified the theoretical findings

Quercetin Pretreatment Attenuates Hepatic Ischemia Reperfusion-Induced Apoptosis and Autophagy by Inhibiting ERK/NF- κ

Background. Hepatic ischemia reperfusion (IR) injury is a common phenomenon in transplantation or trauma. The aim of the present study was to determine the protective effect of quercetin (QE) on hepatic IR injury via the ERK/NF-κB pathway. Methods. Mice were randomized into the sham, IR, QE100 + IR, and QE200 + IR groups. Quercetin was administered intragastrically daily at two doses (100 mg/kg and 200 mg/kg) for 5 days prior to IR injury. The expression levels of liver enzymes, inflammatory cytokines, and other marker proteins were determined at 2, 8, and 24 hours after IR. And they were compared among these groups. Results. Compared with the IR group, the treatment of QE reduced the release of cytokines, leading to inhibition of apoptosis and autophagy via downregulation of the ERK/NF-κB pathway in this model of hepatic IR injury. Conclusion. Apoptosis and autophagy caused by hepatic IR injury were inhibited by QE following a reduction in the release of inflammatory cytokines, and the relationship between the two may be associated with inactivation of the ERK/NF-κB pathway

15-Deoxy- γ

Objective. 15-Deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) reduces inflammation and has been identified as an anti-inflammatory prostaglandin in numerous animal models. In this study, we investigated both effects of 15d-PGJ2 and its protection mechanism in concanavalin A- (ConA-) induced autoimmune hepatitis in mice. Materials and Methods. In vivo, Balb/C mice were injected with ConA (25 mg/kg) to induce acute autoimmune hepatitis, and 15d-PGJ2 (10 μg or 25 μg) was administered 1 h before the ConA injection. The histological grade, proinflammatory cytokine levels, and NF-κB and PPARγ activity were determined 6, 12, and 24 h after the ConA injection. In vitro, LO2 cells and RAW264.7 cells were pretreated with 15d-PGJ2 (2 μM) 1 h before the stimulation with ConA (30 μg/mL). The NF-κB and PPARγ activity were determined 30 min after the ConA administration. Results. Pretreatment with 15d-PGJ2 reduced the pathological effects of ConA-induced autoimmune hepatitis and significantly reduced the levels of cytokines after injection. 15d-PGJ2 activated PPARγ, blocked the degradation of IκBα, and inhibited the translocation of NF-κB into the nucleus. Conclusion. These results indicate that 15d-PGJ2 protects against ConA-induced autoimmune hepatitis by reducing proinflammatory cytokines. This reduction in inflammation may correlate with the activation of PPARγ and the reduction in NF-κB activity

Construction of a cross-species cell landscape at single-cell level.

Individual cells are basic units of life. Despite extensive efforts to characterize the cellular heterogeneity of different organisms, cross-species comparisons of landscape dynamics have not been achieved. Here, we applied single-cell RNA sequencing (scRNA-seq) to map organism-level cell landscapes at multiple life stages for mice, zebrafish and Drosophila. By integrating the comprehensive dataset of > 2.6 million single cells, we constructed a cross-species cell landscape and identified signatures and common pathways that changed throughout the life span. We identified structural inflammation and mitochondrial dysfunction as the most common hallmarks of organism aging, and found that pharmacological activation of mitochondrial metabolism alleviated aging phenotypes in mice. The cross-species cell landscape with other published datasets were stored in an integrated online portal-Cell Landscape. Our work provides a valuable resource for studying lineage development, maturation and aging

Dual Antiplatelet Treatment up to 72 Hours after Ischemic Stroke

BackgroundDual antiplatelet treatment has been shown to reduce recurrence of stroke compared to aspirin alone when initiated early after an acute stroke. The effect of clopidogrel and aspirin versus aspirin alone within 72 hours of acute cerebral ischemia from atherosclerosis has not been well studied.MethodsWe conducted a randomized, double-blind, placebo-controlled, 2-by-2 factorial trial in patients with mild ischemic stroke or high-risk transient ischemic attack (TIA) of presumed atherosclerotic cause, not receiving thrombolysis or thrombectomy in 222 hospitals in China. Patients were randomly assigned within 72 hours after symptom onset in a 1:1 ratio, to receive clopidogrel (300mg on day 1, 75mg daily on days 2-90) and aspirin (100-300mg on day1, 100mg daily on days 2-21), or clopidogrel placebo and aspirin (100-300mg on day1, 100mg daily on days 2-90). There was no interaction between this component of the factorial trial design trial and a second part that tested immediate vs delayed stain treatment and is reported separately. The primary efficacy outcome was a new stroke, and the primary safety outcome was moderate-to-severe bleeding, both within 90 days.ResultsA total of 6100 patients were enrolled, 3050 assigned to each trial group. The qualifying event for enrollment was TIA in 13%. Approximately 13% of patients were assigned to a treatment group within 24 hours and 87% were assigned between 24 and 72 hours of onset of stroke. A new stroke occurred in 222 (7.3%) in the clopidogrel-aspirin group, and 279 (9.2%) in the aspirin group (hazard ratio, 0.79; 95% confidence interval [CI], 0.66-0.94; P=0.008). Moderate-to-severe bleeding occurred in 27 (0.9%) and 13 patients (0.4%), respectively (hazard ratio, 2.08; 95% CI, 1.07-4.04, P=0.03).ConclusionsAmong patients with mild ischemic stroke or high-risk TIA of presumed atherosclerotic cause, combined clopidogrel-aspirin initiated within 72 hours of onset was superior to aspirin alone in reducing the risk of new stroke at 90 days but was associated with a low but increased risk of moderate-to-severe bleeding

A heterozygous moth genome provides insights into herbivory and detoxification

How an insect evolves to become a successful herbivore is of profound biological and practical importance. Herbivores are often adapted to feed on a specific group of evolutionarily and biochemically related host plants1, but the genetic and molecular bases for adaptation to plant defense compounds remain poorly understood2. We report the first whole-genome sequence of a basal lepidopteran species, Plutella xylostella, which contains 18,071 protein-coding and 1,412 unique genes with an expansion of gene families associated with perception and the detoxification of plant defense compounds. A recent expansion of retrotransposons near detoxification-related genes and a wider system used in the metabolism of plant defense compounds are shown to also be involved in the development of insecticide resistance. This work shows the genetic and molecular bases for the evolutionary success of this worldwide herbivore and offers wider insights into insect adaptation to plant feeding, as well as opening avenues for more sustainable pest management.Minsheng You … Simon W Baxter … et al