544 research outputs found
Pseudo-Derivative-Feedback Current Control for Three-Phase Grid-Connected Inverters With LCL Filters
Diazidobis[4,4,5,5-tetramethyl-2-(1,3-thiazol-2-yl)-2-imidazoline-1-oxyl-3-oxide-κ2 O,N]manganese(II)
In the crystal structure of the title compound, [Mn(N3)2(C10H14N3O2S)2], the Mn(II) atom exhibits a roughly octahedral coordination geometry. The Mn(II) atom lies on an inversion centre, thus the asymmetric unit comprises one half-molecule. The metal center is six-coordinated by two azide anions and by two chelating 4,4,5,5-tetramethyl-2-(1,3-thiazol-2-yl)-2-imidazoline-1-oxyl-3-oxide nitronyl nitroxide radical ligands, leading to two six-membered chelate rings
Genome-wide identification, classification and analysis of heat shock transcription factor family in maize
<p>Abstract</p> <p>Background</p> <p>Heat shock response in eukaryotes is transcriptionally regulated by conserved heat shock transcription factors (Hsfs). Hsf genes are represented by a large multigene family in plants and investigation of the Hsf gene family will serve to elucidate the mechanisms by which plants respond to stress. In recent years, reports of genome-wide structural and evolutionary analysis of the entire Hsf gene family have been generated in two model plant systems, <it>Arabidopsis </it>and rice. Maize, an important cereal crop, has represented a model plant for genetics and evolutionary research. Although some Hsf genes have been characterized in maize, analysis of the entire Hsf gene family were not completed following Maize (B73) Genome Sequencing Project.</p> <p>Results</p> <p>A genome-wide analysis was carried out in the present study to identify all Hsfs maize genes. Due to the availability of complete maize genome sequences, 25 nonredundant Hsf genes, named <it>ZmHsfs </it>were identified. Chromosomal location, protein domain and motif organization of ZmHsfs were analyzed in maize genome. The phylogenetic relationships, gene duplications and expression profiles of <it>ZmHsf </it>genes were also presented in this study. Twenty-five ZmHsfs were classified into three major classes (class A, B, and C) according to their structural characteristics and phylogenetic comparisons, and class A was further subdivided into 10 subclasses. Moreover, phylogenetic analysis indicated that the orthologs from the three species (maize, <it>Arabidopsis </it>and rice) were distributed in all three classes, it also revealed diverse Hsf gene family expression patterns in classes and subclasses. Chromosomal/segmental duplications played a key role in Hsf gene family expansion in maize by investigation of gene duplication events. Furthermore, the transcripts of 25 <it>ZmHsf </it>genes were detected in the leaves by heat shock using quantitative real-time PCR. The result demonstrated that <it>ZmHsf </it>genes exhibit different expression levels in heat stress treatment.</p> <p>Conclusions</p> <p>Overall, data obtained from our investigation contributes to a better understanding of the complexity of the maize Hsf gene family and provides the first step towards directing future experimentation designed to perform systematic analysis of the functions of the Hsf gene family.</p
Green tea polyphenol induces significant cell death in human lung cancer cells
Purpose: To investigate the dose–response relationship of green tea polyphenol in an animal model of lung cancer.Methods: The effects of epigallocatechin-3-gallate (EGCG) on the inhibition of xenograft tumor growth, the accumulation of 8-hydroxy-2'-deoxyguanosine (8-OHdG), and apoptosis based on 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay were evaluated in non-small cell lung cancer (NSCLC) cell lines, namely, H1155, H661, and A427 (a human lung carcinoma-derived cell line). The dose-dependent effects of EGCG on H1155 xenograft tumor growth, as well as the levels of EGCG in plasma and tissue, were also determined in male nude mice.Results: EGCG inhibited the growth of NSCLC-derived cell lines (H1155) over a 45-day period. There was a significant reduction (57 %) in tumor weight in EGCG-fed (0.5 %) animals compared with the control group (p < 0.05). Linear regression analysis revealed a dose-dependent reduction in tumor size. MTT assay results revealed inhibition of H1155 cell growth (25 %, p < 0.05) after 24 h treatment with EGCG. The addition of superoxide dismutase (5 U/mL) and catalase (30 U/mL) reduced the inhibitory effect of EGCG. Mice administered 30 mg/kg EGCG via intraperitoneal injection exhibited the least amount of oxidative stress.Conclusion: The results demonstrate the concentration-dependent inhibitory effects of EGCG on lung cancer cells, including H1155 cells, both in vitro and in vivo. The induction of reactive oxygen species, oxidative DNA damage, and apoptosis were evident following EGCG treatment.Keywords: Green tea, Lung cancer, Catechins, Epigallocatechin-3-gallate, Oxidative stress, Oxidative DNA damag
Brain-wide functional connectivity alterations and their cognitive correlates in subjective cognitive decline
BackgroundIndividuals with subjective cognitive decline (SCD) are at risk of developing Alzheimer's Disease (AD). Traditional seed-based analysis has shown biased functional connectivity (FC) in SCD individuals. To investigate unbiased altered FC by the brain-wide association study (BWAS) and to determine its association with cognition in SCD individuals.MethodsMeasure of association (MA) analysis was applied to detect significant voxels with FC changes. Based on these changes, we identified regions of interest (ROIs) and conducted ROI-wise FC analyses. Correlation analyses were then performed between these FC circuits and cognition.ResultsMA analysis identified 10 ROIs with significantly altered voxels. ROI-wise FC analyses revealed 14 strengthened FC, predominantly parietal-occipital link alterations. The FC between the right superior occipital gyrus and the right postcentral gyrus correlated positively with executive function, while the FC between the right middle occipital gyrus and the left angular gyrus correlated positively with episodic memory in SCD individuals.ConclusionSCD involves multifocal impairments, of which regions of default mode network (DMN) and occipital lobe should be specially focused. Cross-hemispheric alterations indicate an internal interactive impairment pattern in SCD. The reduced FC between the right superior occipital gyrus and the right postcentral gyrus, and between the right middle occipital gyrus and the left angular gyrus, which correlate with specific cognitive functions, could serve as potential biomarkers for SCD diagnosis
The ACE2/Apelin Signaling, MicroRNAs, and Hypertension
The renin-angiotensin aldosterone system (RAAS) plays a pivotal role in the development of hypertension. Angiotensin converting enzyme 2 (ACE2), which primarily metabolises angiotensin (Ang) II to generate the beneficial heptapeptide Ang-(1-7), serves as a negative regulator of the RAAS. Apelin is a second catalytic substrate for ACE2 and functions as an inotropic and cardiovascular protective peptide. The physiological effects of Apelin are exerted through binding to its receptor APJ, a seven-transmembrane G protein-coupled receptor that shares significant homology with the Ang II type 1 receptor (AT1R). The deregulation of microRNAs, a class of short and small noncoding RNAs, has been shown to involve cardiovascular remodeling and pathogenesis of hypertension via the activation of the Ang II/AT1R pathway. MicroRNAs are linked with modulation of the ACE2/Apelin signaling, which exhibits beneficial effects in the cardiovascular system and hypertension. The ACE2-coupled crosstalk among the RAAS, the Apelin system, and microRNAs provides an important mechanistic insight into hypertension. This paper focuses on what is known about the ACE2/Apelin signaling and its biological roles, paying particular attention to interactions and crosstalk among the ACE2/Apelin signaling, microRNAs, and hypertension, aiming to facilitate the exploitation of new therapeutic medicine to control hypertension
Model Tests on the Retaining Walls Constructed from Geobags Filled with Construction Waste
Geobag retaining wall using construction waste is a new flexible supporting structure, and the usage of construction waste to fill geobags can facilitate the construction recycling. In this paper, model tests were performed on geobag retaining wall using construction waste. The investigation was concentrated on the slope top settlement, the distribution characteristics of the earth pressures on retaining walls and horizontal wall displacements, and slope failure modes. The results indicated that the ultimate loads that the slope tops with retaining walls could bear were 87.5%~125% higher than that of the slope top without retaining walls. The ultimate loading of strengthened slopes with different slope ratios from 1 : 0.75 to 1 : 0.25 could be reduced by 11.8% to 29.4%. The horizontal displacements of the retaining walls constructed from geobags were distributed in a drum shape, with the greatest horizontal displacements occurring about 1/3~1/2 of the wall height away from the bottom of the wall. As the slope ratio increased, the failure of the slope soil supported by geobag retaining wall using construction waste changed from sliding to sliding-toppling (dominated by sliding) and then to toppling-sliding (dominated by toppling). The range of 1/3~1/2 of wall height is the weak part of the retaining walls, which should be strengthened with certain measures during the process of design and construction
Twin-field quantum key distribution with local frequency reference
Twin-field quantum key distribution (TF-QKD) overcomes the linear rate-loss
limit, which promises a boost of secure key rate over long distance. However,
the complexity of eliminating the frequency differences between the independent
laser sources hinders its practical application. Here, taking the saturated
absorption spectroscopy of acetylene as an absolute reference, we propose and
demonstrate a simple and practical approach to realize TF-QKD without requiring
relative frequency control of the independent laser sources. Adopting the
4-intensity sending-or-not-sending TF-QKD protocol, we experimentally
demonstrate the TF-QKD over 502 km, 301 km and 201 km ultra-low loss optical
fiber respectively. We expect this high-performance scheme will find widespread
usage in future intercity and free-space quantum communication networks.Comment: 13 pages, 5 figures, 7 table
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