225 research outputs found
Power Losses Analysis of Converter for Switched Reluctance Motor Drive with Fault-Tolerant Control
Power losses of power converters are critical information related to the overall system reliability. To quantitatively assess the impact of fault-tolerant control on the reliability of switched reluctance machine (SRM) system, this paper investigates the power loss distribution of the converter for an SRM system under different controls (i.e., with and without fault-tolerant control). Besides, different mission profiles are considered to make the assessment more practical. The drive system is firstly presented under normal and fault tolerant operations, and then followed by the corresponding power losses calculation and analysis. Simulations are carried out on an SRM drive system to support the power losses analysis
β-Arrestin1 Mediates the Endocytosis and Functions of Macrophage Migration Inhibitory Factor
Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine, regulating inflammatory and immune responses. MIF binds to cell surface receptor CD74, resulting in both rapid and sustained ERK activation. It was reported that MIF-induced rapid ERK activation requires its co-receptor CD44. But the exact mechanism underlying sustained ERK activation is not well understood. In the current study, we described a detailed mechanism of MIF mediated sustained ERK activation. We found that β-arrestin1, a scaffold protein involved in the activation of the MAPK cascade, interacts with CD74 upon MIF stimulation, resulting in CD74-mediated MIF endocytosis in a chlorpromazine (CPZ)-sensitive manner. β-arrestin1 is also involved in endocytotic MIF signaling, leading to sustained ERK activation. Therefore β-arrestin1 plays a central role in coupling MIF endocytosis to sustained ERK activation
Increased Numbers of NK Cells, NKT-Like Cells, and NK Inhibitory Receptors in Peripheral Blood of Patients with Chronic Obstructive Pulmonary Disease
T cells and B cells participate in the pathogenesis of COPD. Currently, NK cells and NKT cells have gained increasing attention. In the present study, 19 COPD patients and 12 healthy nonsmokers (HNS) were recruited, and their pulmonary function was assessed. The frequencies of CD3+ T, CD4+ T, CD8+ T, B, NK, and NKT-like cells were determined using flow cytometry. The frequencies of spontaneous and inducible IFN-γ+ or CD107a+ NK and NKT-like cells as well as activating or inhibitory receptors were also detected. The potential association of lymphocyte subsets with disease severity was further analyzed. Significantly decreased numbers of CD3+ and CD4+ T cells, and the CD4+/CD8+ ratio, but increased numbers of CD3−CD56+ NK and CD3+CD56+ NKT-like cells were observed in COPD patients compared to HNS. The frequencies of inducible IFN-γ-secreting NK and NKT-like cells were less in COPD patients. The frequencies of CD158a and CD158b on NK cells and CD158b on NKT-like cells were greater. The frequency of CD158b+ NK cells was negatively correlated with FEV1% prediction and FEV1/FVC. Our data indicate that COPD patients have immune dysfunction, and higher frequencies of inhibitory NK cells and NKT-like cells may participate in the pathogenesis of COPD
Flexible heteroarotinoid (Flex-Het) SHetA2 inhibits angiogenesis in vitro and in vivo
Flexible heteroarotinoids (Flex-Hets) compounds regulate growth, differentiation and apoptosis in cancer cells. The hypothesis of this study was that the lead Flex-Het, SHetA2, inhibits angiogenesis by blocking cytokine release from cancer cells. SHetA2 altered secretion of thrombospondin-4 (TSP-4), vascular endothelial growth factor A (VEGF) and fibroblast growth factor (bFGF) proteins from normal and cancerous ovarian and renal cultures. Thymidine phosphorylase (TP) expression was inhibited in cancer, but not normal cultures. Endothelial tube formation was stimulated by conditioned media from cancer but not normal cultures, and SHetA2 reduced secretion of this angiogenic activity. SHetA2 directly inhibited endothelial cell tube formation and proliferation through G1 cell cycle arrest, but not apoptosis. Recombinant TP reversed SHetA2 anti-angiogenic activity. SHetA2 inhibition of in vivo angiogenesis was observed in Caki-1 renal cancer xenografts. In conclusion, SHetA2 inhibits angiogenesis through alteration of angiogenic factor secretion by cancer cells and through direct effects on endothelial cells
Generation of Monoclonal Antibodies against Highly Conserved Antigens
Background: Therapeutic antibody development is one of the fastest growing areas of the pharmaceutical industry. Generating high-quality monoclonal antibodies against a given therapeutic target is very crucial for the success of the drug development. However, due to immune tolerance, some proteins that are highly conserved between mice and humans are not very immunogenic in mice, making it difficult to generate antibodies using a conventional approach. Methodology/Principal Findings: In this report, the impaired immune tolerance of NZB/W mice was exploited to generate monoclonal antibodies against highly conserved or self-antigens. Using two highly conserved human antigens (MIF and HMGB1) and one mouse self-antigen (TNF-alpha) as examples, we demonstrate here that multiple clones of high affinity, highly specific antibodies with desired biological activities can be generated, using the NZB/W mouse as the immunization host and a T cell-specific tag fused to a recombinant antigen to stimulate the immune system. Conclusions/Significance: We developed an efficient and universal method for generating surrogate or therapeuti
The growing burden of generalized myasthenia gravis: a population-based retrospective cohort study in Taiwan
BackgroundThe prevalence of myasthenia gravis is increasing in many countries, including Asia. As treatment options expand, population-based information about the disease burden can inform health technology assessments.MethodsWe conducted a population-based retrospective cohort study using the Taiwan National Healthcare Insurance Research database and Death Registry to describe the epidemiology, disease burden and treatment patterns of generalized myasthenia gravis (gMG) from 2009 to 2019. Episodes of hepatitis B virus (HBV) infection or reactivation were explored.ResultsThe number of patients with gMG increased from 1,576 in 2009 to 2,638 in 2019 and the mean (standard deviation) age from 51.63 (17.32) to 55.38 (16.29) years. The female:male ratio was 1.3:1. Frequently reported co-morbidities were hypertension (32–34% of patients), diabetes mellitus (16–21%) and malignancies (12–17%). The prevalence of patients with gMG increased annually from 6.83/100,000 population in 2009 to 11.18/100,000 population in 2019 (p < 0.0001). There was no temporal trend in all-cause fatality rates (range 2.76–3.79/100 patients annually) or gMG incidence rates (2.4–3.17/100,000 population annually). First-line treatment was with pyridostigmine (82%), steroids (58%), and azathioprine (11%). There was minimal change in treatment patterns over time. Among 147 new HBV infections, 32 (22%) received ≥4 weeks of antiviral therapy suggesting chronic infection. The HBV reactivation rate was 7.2%.ConclusionThe epidemiology of gMG in Taiwan is evolving rapidly, with higher prevalence rates and increasing involvement of older age-groups suggesting a growing burden of disease and associated healthcare costs. HBV infection or reactivation may pose a previously unrecognized recognized risk for patients with gMG receiving immunosuppressants
Chromosome-level genome assembly of a high-altitude-adapted frog (Rana kukunoris) from the Tibetan plateau provides insight into amphibian genome evolution and adaptation
Background The high-altitude-adapted frog Rana kukunoris, occurring on the Tibetan plateau, is an excellent model to study life history evolution and adaptation to harsh high-altitude environments. However, genomic resources for this species are still underdeveloped constraining attempts to investigate the underpinnings of adaptation. Results The R. kukunoris genome was assembled to a size of 4.83 Gb and the contig N50 was 1.80 Mb. The 6555 contigs were clustered and ordered into 12 pseudo-chromosomes covering similar to 93.07% of the assembled genome. In total, 32,304 genes were functionally annotated. Synteny analysis between the genomes of R. kukunoris and a low latitude species Rana temporaria showed a high degree of chromosome level synteny with one fusion event between chr11 and chr13 forming pseudo-chromosome 11 in R. kukunoris. Characterization of features of the R. kukunoris genome identified that 61.5% consisted of transposable elements and expansions of gene families related to cell nucleus structure and taste sense were identified. Ninety-five single-copy orthologous genes were identified as being under positive selection and had functions associated with the positive regulation of proteins in the catabolic process and negative regulation of developmental growth. These gene family expansions and positively selected genes indicate regions for further interrogation to understand adaptation to high altitude. Conclusions Here, we reported a high-quality chromosome-level genome assembly of a high-altitude amphibian species using a combination of Illumina, PacBio and Hi-C sequencing technologies. This genome assembly provides a valuable resource for subsequent research on R. kukunoris genomics and amphibian genome evolution in general.Peer reviewe
Glycyrrhizin Ameliorates Imiquimod-Induced Psoriasis-like Skin Lesions in BALB/c Mice and Inhibits TNF-a-Induced ICAM-1 Expression via NF-κB/MAPK in HaCaT Cells
Genome sequencing and analysis of the paclitaxelproducing endophytic fungus \u3cem\u3ePenicillium aurantiogriseum\u3c/em\u3e NRRL 62431
Background
Paclitaxel (Taxolâ„¢) is an important anticancer drug with a unique mode of action. The biosynthesis of paclitaxel had been considered restricted to the Taxus species until it was discovered in Taxomyces andreanae, an endophytic fungus of T. brevifolia. Subsequently, paclitaxel was found in hazel (Corylus avellana L.) and in several other endophytic fungi. The distribution of paclitaxel in plants and endophytic fungi and the reported sequence homology of key genes in paclitaxel biosynthesis between plant and fungi species raises the question about whether the origin of this pathway in these two physically associated groups could have been facilitated by horizontal gene transfer.
Results
The ability of the endophytic fungus of hazel Penicillium aurantiogriseum NRRL 62431 to independently synthesize paclitaxel was established by liquid chromatography-mass spectrometry and proton nuclear magnetic resonance. The genome of Penicillium aurantiogriseum NRRL 62431 was sequenced and gene candidates that may be involved in paclitaxel biosynthesis were identified by comparison with the 13 known paclitaxel biosynthetic genes in Taxus. We found that paclitaxel biosynthetic gene candidates in P. aurantiogriseum NRRL 62431 have evolved independently and that horizontal gene transfer between this endophytic fungus and its plant host is unlikely.
Conclusions
Our findings shed new light on how paclitaxel-producing endophytic fungi synthesize paclitaxel, and will facilitate metabolic engineering for the industrial production of paclitaxel from fungi
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