486 research outputs found

    An improved control method of power electronic converters in low voltage micro-grid

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    {4-[5-(4-tert-Butyl­phen­yl)-1,3,4-oxa­diazol-2-yl]phen­yl}methanol

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    In the title compound, C19H20N2O2, the 1,3,4-oxadiazole ring is almost coplanar with the two neighboring benzene rings [dihedral angles = 3.76 (4) and 5.49 (4)°]. In the crystal, mol­ecules are connected by strong inter­molecular O—H⋯N hydrogen bonds, forming chains parallel to the c axis

    Self-suppressed quantum diffusion and fundamental noise limit of soliton microcombs

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    Quantum diffusion of soliton microcombs has long been recognized as their fundamental noise limit. Here we surpass such limit by utilizing dispersive wave dynamics in multimode microresonators. Through the recoil force provided by these dispersive waves, the quantum diffusion can be suppressed to a much lower level that forms the ultimate fundamental noise limit of soliton microcombs. Our findings enable coherence engineering of soliton microcombs in the quantum-limited regime, providing critical guidelines for using soliton microcombs to synthesize ultralow-noise microwave and optical signals.Comment: 8 pages, 5 figure

    Pharmacokinetics and safety of repirinast tablets in healthy Chinese subjects

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    Repirinast is a new, synthetic, disodium cromoglycate-like antiallergic agent for oral administration in humans. This study evaluated the safety, tolerability and pharmacokinetics of repirinast tablets in healthy Chinese volunteers. This was a phase I, open-label, randomized, single- and multiple-dose study. Subjects were assigned to receive a single dose of repirinast tablet at either 150, 300, or 450 mg, or multiple doses of 150 mg twice daily for 5 days. Plasma samples were analyzed with LC-MS/MS. Pharmacokinetic parameters of active metabolite MY-1250 (deesterified repirinast) were calculated using non-compartmental analysis with WinNonlin software. Statistical analysis was performed using SPSS software. All adverse events (AEs) were mild and of limited duration. No serious adverse event (SAE), death or withdrawal from the study was observed. In the single-dose study, Cmax was reached at about 0.75 hour, and the mean t1/2 was approximately 16.21 hours. Area under curve (AUC) and Cmax increased with dose escalation, but dose proportionality was not observed over the range of 150 to 450 mg. In the multiple-dose study, the steady-state was reached within 3 days with no accumulation. Repirinast tablet was well tolerated in healthy Chinese subjects

    Health status prediction for the elderly based on machine learning

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    Health and social care services are crucial to old people. The provision of services to the elderly with care needs requires more accurate predictions of the health status of the elderly to rationalize the allocation of the limited social care resources. The traditional analytical methods have proved incapable of predicting the demands of today's society, compared to which machine learning methods can more accurately capture the nonlinear relationships between the variables. To ascertain visually the performance of these machine learning methods regarding the prediction of the elderly's care needs, we designed and verified the experiment

    Investigation of the mechanisms on the abnormal features observed in thermal-mechanical testing of AA6061 under extrusion conditions

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    Hot extrusion is the most common forming technology for aluminium alloy AA6061 due to its good extrudability, and thus it is important to study its high-temperature deformation characteristics. In this study, three abnormal features are observed in thermal-mechanical testing under extrusion conditions of AA6061 specimens from one billet: 1) Two types of specimens with grey-coloured surface or silver-coloured surface appear after solution heat treatment (SHT); 2) The silver-coloured specimens show orange peel surface after hot compression tests; 3) The silver-coloured specimens have lower flow stresses than the grey-coloured specimens. This paper investigates the mechanisms behind the above abnormal features. A laser scanning confocal microscope is employed to examine the surface roughening, and electron back scatter diffraction is used to characterise microstructural changes. It is found that the main causes of the above behaviour are due to different initial grain morphologies and the evolution of dislocation density after SHT. The silver-coloured specimens initially have smaller columnar grains which undergo recrystallisation and extensive growth during SHT, and the dislocation density decreases significantly, leading to orange peel defect and low flow stress during compression tests, respectively. The grey-coloured specimens have larger columnar grains. After SHT, some grains undergo recrystallisation, but others still maintain the shape of the large columnar grains, and the dislocation density does not change significantly, resulting in surface oxidation with smooth surface after thermal-mechanical testing and 10–25 MPa (30–50%) higher flow stress compared to the silver-coloured specimens in compression tests

    Mendelian randomization analysis revealed a gut microbiota–mammary axis in breast cancer

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    BackgroundObservational epidemiological studies suggested an association between the gut microbiota and breast cancer, but it remains unclear whether the gut microbiota causally influences the risk of breast cancer. We employed two-sample Mendelian randomization (MR) analysis to investigate this association.MethodsWe used summary statistics of the gut microbiome from a genome-wide association study (GWAS) of 18,340 individuals in the MiBioGen study. GWAS summary statistics for overall breast cancer risk and hormone receptor subtype-specific analyses were obtained from the UK Biobank and FinnGen databases, totaling 400,000 individuals. The inverse variance-weighted (IVW) MR method was used to examine the causal relationship between the gut microbiome and breast cancer and its subtypes. Sensitivity analyses were conducted using maximum likelihood, MR-Egger, and MR pleiotropic residual sums and outliers methods.ResultsThe IVW estimates indicated that an increased abundance of Genus_Sellimonas is causally associated with an increased risk of ER+ breast cancer [odds ratio (OR) = 1.09, p = 1.72E−04, false discovery rate (FDR) = 0.02], whereas an increased abundance of Genus_Adlercreutzia was protective against ER+ breast cancer (OR = 0.88, p = 6.62E−04, FDR = 0.04). For Her2+ breast cancer, an increased abundance of Genus_Ruminococcus2 was associated with a decreased risk (OR = 0.77, p = 4.91E−04, FDR = 0.04), whereas an increased abundance of Genus_Erysipelatoclostridium was associated with an increased risk (OR = 1.25, p = 6.58E−04, FDR = 0.04). No evidence of heterogeneity or horizontal pleiotropy was found.ConclusionOur study revealed a gut microbiota–mammary axis, providing important data supporting the potential use of the gut microbiome as a candidate target for breast cancer prevention, diagnosis, and treatment
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