Associations of vitamin D-related single nucleotide polymorphisms with post-stroke depression among ischemic stroke population

ObjectiveTo investigate the relationship between single nucleotide polymorphisms (SNPs) related to vitamin D (VitD) metabolism and post-stroke depression (PSD) in patients with ischemic stroke.MethodsA total of 210 patients with ischemic stroke were enrolled at the Department of Neurology in Xiangya Hospital, Central South University, from July 2019 to August 2021. SNPs in the VitD metabolic pathway (VDR, CYP2R1, CYP24A1, and CYP27B1) were genotyped using the SNPscan™ multiplex SNP typing kit. Demographic and clinical data were collected using a standardized questionnaire. Multiple genetic models including dominant, recessive, and over-dominant models were utilized to analyze the associations between SNPs and PSD.ResultsIn the dominant, recessive, and over-dominant models, no significant association was observed between the selected SNPs in the CYP24A1 and CYP2R1 genes and PSD. However, univariate and multivariate logistic regression analysis revealed that the CYP27B1 rs10877012 G/G genotype was associated with a decreased risk of PSD (OR: 0.41, 95% CI: 0.18–0.92, p = 0.030 and OR: 0.42, 95% CI: 0.18–0.98, p = 0.040, respectively). Furthermore, haplotype association analysis indicated that rs11568820-rs1544410-rs2228570-rs7975232-rs731236 CCGAA haplotype in the VDR gene was associated with a reduced risk of PSD (OR: 0.14, 95% CI: 0.03–0.65, p = 0.010), whereas no significant association was observed between haplotypes in the CYP2R1 and CYP24A1 genes and PSD.ConclusionOur findings suggest that the polymorphisms of VitD metabolic pathway genes VDR and CYP27B1 may be associated with PSD in patients with ischemic stroke

Modular Combined DC-DC Autotransformer for Offshore Wind Power Integration with DC Collection

Offshore wind farms (OWFs) integration are attractive extensively for furnishing more robust power than land wind farms. This paper introduces a modular combined DC-DC autotransformer (MCAT), which contributes to the offshore wind power integration of DC grids with different voltage levels. Traditional DC transformers contains medium- or high-frequency converter transformers, which have the disadvantages of high manufacturing difficulty and cost. These shortcomings seriously affect the progress of commercial application of DC transformers. To solve these problems, in the proposed MCAT, converter transformers are replaced with a DC-isolation capacitor and a compensation inductor in series to reduce the footprint of offshore platforms and improve economy. Theoretical analysis is carried out for the MCAT operation principle. Selection methods of main circuit parameters for the MCAT are discussed in detail. Then, corresponding control strategies of the MCAT are proposed. Finally, the effectiveness of the proposed MCAT and its control strategies are validated by time domain simulations in PSCAD/EMTDC. The time-domain simulation results show the correctness of the main circuit parameters and the rationality of the MCAT control strategies

Optimal operation strategy for subway HVAC system in transition seasons

This paper mainly studied the operation strategy for subway VAC system during transition seasons. Two modes including WF-AC (Whole Fresh air- Air Conditioning) mode and B/E-V (Back/Exhausted fan-Ventilation) mode were selected based on energy saving principle. In order to decide the optimal operation mode, the calculation method of “switching temperature” was proposed. The main influencing factors of the switching condition include indoor cooling load, COP of the chilled-water-system, temperature difference of the supply air, efficiency of fan and the resistance of air duct. Also, the transfer temperature diagram is provided based on proposed calculation method, which is suitable for engineering use. The aim of this study is to regulate the operation mode and to promote energy saving in subway station

Regulation Principles of Power Flow Gradients to Multiple Characteristic Independent Variables in UPFC Embedded Power System

The power flows in the unified power flow controller (UPFC) embedded system is mainly regulated by the two variables containing the magnitude and the phase angle of the output series inserted voltage (OSIV) of UPFC. Different value combinations of the two variables can form multiple regulation modes of OSIV, and the regulation principles and efficiencies for power flows are distinct by different regulation modes. This paper dedicates to research the regulation principles of active and reactive power flow gradients (PFG) to multiple characteristic independent variables (CIVs) at several selected critical points (SCP) of the system in different operation conditions. The CIVs contains the magnitude of OSIV, the phase angle of OSIV, and the phase difference of the system. First, multiple power flow regulation modes of OSIV are designed, the mathematical models of the PFG to each CIV at each SCP are established, and the theoretical principles for the PFG to each CIV at each SCP are analyzed and compared. Next, four typical operation conditions of the system and four regulation scenarios are assumed and case studies for the PFG to each CIV at different SCP are carried out. The test results at each SCP are analyzed both in the two-dimensional planes and three-dimensional spaces. The regulation principles and efficiencies of PFG to each CIV at different SCP are compared with each other and summarized, which can offer useful references for practical engineering and applications of UPFC

Two novel SiC phases: structure, mechanical, and transport properties

Two novel phases of SiC are put forward in this paper, in which the crystal structural, mechanical, and electronic properties, as well as effective mass and carrier mobility of SiC in the Pnnm phase ( Pnnm -SiC) and Pm phase ( Pm -SiC) are researched utilizing first principles calculations. Both of the novel SiC phases are certificated to have good mechanical and dynamic stability. Through analysis of the three-dimensional perspective of Young’s modulus, shear modulus and Poisson’s ratio, visible anisotropies of mechanical properties are found. The band structure calculations predict two wide bandgap semiconductors, that the Pnnm -SiC is an indirect with a bandgap value of 3.12 eV, While the Pm -SiC is a quasi-direct with a bandgap value of 2.64 eV, which indicates the Pm -SiC has a higher application potential in the optoelectronic device area. An extremely large electronic mobility (7200 cm ^2 V ^−1 s ^−1 ) is found in the Pnnm -SiC. Based on the wide band gap, large carrier mobility, good mechanical and dynamic stability, the Pnnm -SiC is a promising material in the field of high performance electronic device in harsh environment

First-Principles Study on III-Nitride Polymorphs: AlN/GaN/InN in the Pmn21 Phase

The structural, mechanical, and electronic properties, as well as stability, elastic anisotropy and effective mass of AlN/GaN/InN in the Pmn21 phase were determined using density functional theory (DFT). The phonon dispersion spectra and elastic constants certify the dynamic and mechanical stability at ambient pressure, and the relative enthalpies were lower than those of most proposed III-nitride polymorphs. The mechanical properties reveal that Pmn21-AlN and Pmn21-GaN possess a high Vickers hardness of 16.3 GPa and 12.8 GPa. Pmn21-AlN, Pmn21-GaN and Pmn21-InN are all direct semiconductor materials within the HSE06 hybrid functional, and their calculated energy band gaps are 5.17 eV, 2.77 eV and 0.47 eV, respectively. The calculated direct energy band gaps and mechanical properties of AlN/GaN/InN in the Pmn21 phase reveal that these three polymorphs may possess great potential for industrial applications in the future

Magnetic-actuated "capillary container" for versatile three-dimensional fluid interface manipulation

Fluid interfaces are omnipresent in nature. Engineering the fluid interface is essential to study interfacial processes for basic research and industrial applications. However, it remains challenging to precisely control the fluid interface because of its fluidity and instability. Here, we proposed a magnetic-actuated "capillary container" to realize three-dimensional (3D) fluid interface creation and programmable dynamic manipulation. By wettability modification, 3D fluid interfaces with predesigned sizes and geometries can be constructed in air, water, and oils. Multiple motion modes were realized by adjusting the container's structure and magnetic field. Besides, we demonstrated its feasibility in various fluids by performing selective fluid collection and chemical reaction manipulations. The container can also be encapsulated with an interfacial gelation reaction. Using this process, diverse free-standing 3D membranes were produced, and the dynamic release of riboflavin (vitamin B2) was studied. This versatile capillary container will provide a promising platform for open microfluidics, interfacial chemistry, and biomedical engineering.ISSN:2375-254

Tunable Fluid-Type Metasurface for Wide-Angle and Multifrequency Water-Air Acoustic Transmission

Efficient acoustic communication across the water-air interface remains a great challenge owing to the extreme acoustic impedance mismatch. Few present acoustic metamaterials can be constructed on the free air-water interface for enhancing the acoustic transmission because of the interface instability. Previous strategies overcoming this difficulty were limited in practical usage, as well as the wide-angle and multifrequency acoustic transmission. Here, we report a simple and practical way to obtain the wide-angle and multifrequency water-air acoustic transmission with a tunable fluid-type acoustic metasurface (FAM). The FAM has a transmission enhancement of acoustic energy over 200 times, with a thickness less than the wavelength in water by three orders of magnitude. The FAM can work at an almost arbitrary water-to-air incident angle, and the operating frequencies can be flexibly adjusted. Multifrequency transmissions can be obtained with multilayer FAMs. In experiments, the FAM is demonstrated to be stable enough for practical applications and has the transmission enhancement of over 20 dB for wide frequencies. The transmission enhancement of music signal across the water-air interface was performed to demonstrate the applications in acoustic communications. The FAM will benefit various applications in hydroacoustics and oceanography

Bio-inspired vertebral design for scalable and flexible perovskite solar cells

Flexible perovskite solar cells suffer huge efficiency loss upon area scale-up due to brittleness of ITO and poor perovskite film quality. Here Meng et al. solve this by inserting a conductive and glued polymer layer between ITO and perovskite layers and obtain efficiency of 17% for 30 cm2 devices