维生素D治疗全面性发育迟缓患儿的临床疗效研究

背景 除了某些有明确病因的代谢性疾病导致的全面性发育迟缓(GDD),康复治疗是GDD的主要治疗方式;维生素D通过影响神经营养因子在调节神经细胞的发育和分化方面发挥着重要的神经保护作用;但目前关于补充维生素D对GDD患儿临床疗效的研究开展较少。目的 探讨补充不同剂量的维生素D对GDD患儿康复治疗的临床效果。方法 于2020年9月—2022年6月选取在郑州大学第三附属医院康复医学科首次住院就诊的120例GDD患儿为研究对象,采用随机区组化的方法将其分为常规组(38例)、400 U组(37例)和1 200 U组(35例)。常规组仅进行常规康复治疗;400 U组在常规康复治疗的基础上给予口服400 U/d维生素D;1 200 U组在常规康复训练的基础上给予口服1 200 U/d维生素D。收集3组患儿的性别、就诊年龄等基本资料;于入院时(治疗前)及第3个疗程末(治疗后)行血清25羟维生素D[25(OH)D]水平检测和Gesell发育量表评估[评估适应能力、大运动能力、精细运动能力、语言能力和社交能力5个能区的发育商(DQ)];记录发生在患儿住院期间不良事件的次数,并对上述资料进行分析比较。结果 3组患儿性别、居住地、出生季节、分娩方式、就诊年龄、出生体质量、出生胎龄、主要就诊原因比较,差异均无统计学意义(P>0.05)。治疗前,3组患儿25(OH)D水平、Gesell量表各能区DQ值比较,差异均无统计学意义(P>0.05);治疗后,1 200 U组患儿血25(OH)D水平、Gesell量表大运动能力、精细运动能力、语言能力DQ值高于常规组(P<0.05)。第1、2疗程期间,3组患儿不良事件发生率比较,差异无统计学意义(P>0.05);第3疗程期间,1 200 U组患儿不良事件发生率低于常规组及400 U组(P<0.05)。结论 补充1 200 U维生素D对GDD患儿的康复疗效有益,且能减少康复期间不良事件的发生率。

复杂越野场景无人履带平台3D语义占据预测方法

为了理解和处理复杂越野场景中环境要素形状不规则、地形多变及路面属性复杂等问题,提出了一种基于多模态融合感知的3D语义占据预测方法.首先,基于图像和激光雷达融合网络获取初始3D语义标签;然后,对越野场景稀疏点云采用贝叶斯稠密化算法补全3D语义占据标签;最后,生成包含复杂环境要素大小、位置和语义信息的3D语义占据栅格地图.试验结果表明,该方法能够有效地提取和表示复杂越野环境中的3D信息,为复杂越野环境下无人履带平台的路径规划提供了更加准确和丰富的先验信息.

3D打印矩形粗糙通道内火箭煤油流动换热特性试验方法研究

为探究3D打印再生冷却通道在液体火箭发动机推力室中的替代应用特性,研制了具有不同内表面粗糙度的正弦波纹结构3D打印304不锈钢矩形通道。内截面名义尺寸为2.0 mm×2.0 mm,设计粗糙度分别为6.3、25.0、100.0μm,实际粗糙度Ra分别为11.88、12.70、17.53μm,通过将高温电阻率法和像素法相结合获得了3D打印通道的实际内径和壁厚,修正了火箭煤油流动换热的内壁温和热流密度,建立了3D打印粗糙通道内火箭煤油流动换热特性试验研究方法。试验参数如下:压力处于15~20 MPa范围、质量流速在12450~24900 kg·m^(-2)·s^(-1)之间、热流密度为5~15 MW·m^(-2)、流体温度为-150℃。研究结果表明:火箭煤油流动换热特性受到热流密度、流体温度和质量流速的影响;流体温度处于50~135℃范围内,换热系数增加约25%~33%;热流密度处于5.0~15.0 MW·m^(-2)范围内,换热系数增加了8.3%;质量流速为12450~24900 kg·m^(-2)·s^(-1)范围内,换热系数增加了60.2%。粗糙度增加对火箭煤油流动换热起到强化作用,粗糙度从11.88μm增加到17.53μm时,换热强化幅度超过20%以上。该研究可为3D打印通道在火箭发动机推力室中的替代应用提供参考。

绝经后女性维生素D水平与生殖特点和运动膳食情况的关系

背景:研究证明绝经后骨质疏松症与女性生殖特点和运动膳食有关,但是鲜有研究证明女性生殖特点及运动膳食是否对绝经后女性维生素D有影响。目的:探讨北京市绝经后女性维生素D水平与女性生殖特点和运动膳食情况的关系及其影响因素。方法:选取2017年9月至2018年5月北京市多个城区的17个社区现场问卷调查的727例46-75岁绝经后女性作为研究对象,问卷内容包括受试者的基本信息和月经史、绝经史、妊娠史、运动膳食情况等。采用电化学发光免疫分析仪及其配套试剂测定25-(OH)D水平;使用双能X射线骨密度检测仪测定腰椎(L1-L4、整体)和双髋关节(股骨颈、整体)的骨密度和T值;观察维生素D与生殖特点和运动膳食的相关性,并进行维生素D的影响因素分析。结果与结论:①维生素D正常组136例(18.7%),维生素D不足组389例(53.5%),维生素D缺乏组202例(27.8%);平均维生素D水平为(15.60±5.85)ng/mL。②随着维生素D水平的升高,不同部位的骨密度值及T值也随之升高。③维生素D水平与初潮年龄、月经持续天数、绝经阶段、运动情况、饮食类型、饮食偏好均呈正相关(P<0.05);与月经周期、绝经年龄、生育次数均呈负相关(P<0.05);与初孕年龄、怀孕次数无相关性(P>0.05)。④多因素有序Logistic回归分析结果显示,喝奶制品频率对绝经后女性维生素D值存在正向相关(P<0.05),且奶制品是维生素D水平的保护因素。⑤调查结果说明,北京市绝经后女性维生素D水平普遍不足、骨密度值普遍低下,维生素D水平与部分生殖特点、运动膳食情况存在关联,且其中喝奶制品是其保护因素。因此可以通过开展相关骨质疏松的健康教育,对绝经后女性膳食情况进行调整加以干预,增加体内维生素D含量,以期增加骨密度值,减少绝经后骨质疏松患病率。

一种前后台结合的Pipelined ADC校准技术

针对Pipelined模数转换器(ADC)中采样电容失配和运放增益误差带来的非线性问题,提出了一种前后台结合的Pipelined ADC校准技术。前台校准技术通过对ADC量化结果的余量分析,补偿相应流水级的量化结果,后台校准技术基于伪随机(PN)注入的方式,利用PN的统计特性校准增益误差。本校准技术在系统级建模和RTL级电路设计的基础上,实现了现场可编程门阵列(FPGA)验证并成功流片。测试结果显示,在1 GS/s采样速率下,校准精度为14 bit的Pipelined ADC的有效位数从9.30 bit提高到9.99 bit,信噪比提高约4 dB,无杂散动态范围提高9.5 dB,积分非线性(INL)降低约10 LSB。

Therapeutic Effect of Rhodopseudomonas palustris-Bioconverted Extract of Lycium barbarum on Rats with Lead Exposure

Lead is a ubiquitous pollutant and Pb pollution is a global public health problem.Lead has been reported to induce multiple adverse effects,including reproductive toxicity,neurotoxicity,carcinogenicity,nephrotoxicity,immunotoxicity,and hypertension[1].The traditional medical treatment available for Pb poisoning is chelation,which can save lives in individuals with very high blood Pb levels.The commonly used chelating agents include CaNa2EDTA and meso-2,3-dimercaptosuccinic acid.However,chelation therapy has strong short-term effects on the overall long-term management of Pb exposure.

Recent advancements in continuously scalable conversion-ratio switched-capacitor converter

Switched-capacitor(SC)DC-DC converter[1]is an impor-tant alternative to inductive DC-DC converter,in terms of removing the bulky power inductor.Hence,it is widely used in low-profile,low-power applications,such as the internet of things(IoT)sensor nodes and energy harvesting[2].Mean-while,considering that capacitor has a much higher energy density than inductor,high-power applications.

Modeling the System for Hybrid Renewable Energy Using Highly Efficient Converters and Generator

High-efficient isolated DC/DC converters with a high-efficiency synchronous reluctance generator(SRG)are the ultimate solutions in DC microgrid systems.The design and modeling of isolated DC/DC converters with the performance of SRG are carried out.On the generator side,reactive and active powers are used as pulse width modulation(PWM)control variables.Further,the flux estimator is used.Three-phase PWM rectifier is used by applying space vector modulation(SVM)with a constant switching frequency for direct power control.Further,the paper also includes the experimental validation of the results.The paper also proposes that highly efficient power converters and synchronous reluctance generators are required to achieve high performance for hybrid renewable energy systems applications.

A real-time calibration method based on time-to-digital converter for accelerator timing system

The high-intensity heavy-ion accelerator facility(HIAF)is a scientific research facility complex composed of multiple cas-cade accelerators of different types,which pose a scheduling problem for devices distributed over a certain range of 2 km,involving over a hundred devices.The white rabbit,a technology-enhancing Gigabit Ethernet,has shown the capability of scheduling distributed timing devices but still faces the challenge of obtaining real-time synchronization calibration param-eters with high precision.This study presents a calibration system based on a time-to-digital converter implemented on an ARM-based System-on-Chip(SoC).The system consists of four multi-sample delay lines,a bubble-proof encoder,an edge controller for managing data from different channels,and a highly effective calibration module that benefits from the SoC architecture.The performance was evaluated with an average RMS precision of 5.51 ps by measuring the time intervals from 0 to 24,000 ps with 120,000 data for every test.The design presented in this study refines the calibration precision of the HIAF timing system.This eliminates the errors caused by manual calibration without efficiency loss and provides data support for fault diagnosis.It can also be easily tailored or ported to other devices for specific applications and provides more space for developing timing systems for particle accelerators,such as white rabbits on HIAF.

Robust fixed-time flight controller for a dual-system convertible UAV in the cruise mode

This paper investigates the attitude tracking control problem for the cruise mode of a dual-system convertible unmanned aerial vehicle(UAV)in the presence of parameter uncertainties,unmodeled uncertainties and wind disturbances.First,a fixed-time disturbance observer(FXDO)based on the bi-limit homogeneity theory is designed to estimate the lumped disturbance of the convertible UAV model.Then,a fixed-time integral sliding mode control(FXISMC)is combined with the FXDO to achieve strong robustness and chattering reduction.Bi-limit homogeneity theory and Lyapunov theory are applied to provide detailed proof of the fixed-time stability.Finally,numerical simulation experimental results verify the robustness of the proposed algorithm to model parameter uncertainties and wind disturbances.In addition,the proposed algorithm is deployed in a open-source UAV autopilot and its effectiveness is further demonstrated by hardware-in-the-loop experimental results.

Robust optical mode converter based on topological waveguide arrays

Optical mode converters are essential for enhancing the capacity of optical communication systems. However, fabrication errors restrict the further improvement of conventional mode converters. To address this challenge, we have designed an on-chip TE0–TE1mode converter based on topologically protected waveguide arrays. The simulation results demonstrate that the converter exhibits a mode coupling efficiency of 93.5% near 1550 nm and can tolerate a relative fabrication error of 30%. Our design approach can be extended to enhance the robustness for other integrated photonic devices, beneficial for future development of optical network systems.

Energy-Efficient Implementation of BCD to Excess-3 Code Converter for Nano-Communication Using QCA Technology

Code converters are essential in digital nano communication;therefore,a low-complexity optimal QCA layout for a BCD to Excess-3 code converter has been proposed in this paper.A QCA clockphase-based design technique was adopted to investigate integration with other complicated circuits.Using a unique XOR gate,the recommended circuit’s cell complexity has been decreased.The findings produced using the QCADesigner-2.0.3,a reliable simulation tool,prove the effectiveness of the current structure over earlier designs by considering the number of cells deployed,the area occupied,and the latency as design metrics.In addition,the popular tool QCAPro was used to estimate the energy dissipation of the proposed design.The proposed technique reduces the occupied space by∼40%,improves cell complexity by∼20%,and reduces energy dissipation by∼1.8 times(atγ=1.5EK)compared to the current scalable designs.This paper also studied the suggested structure’s energy dissipation and compared it to existing works for a better performance evaluation.

Modular System of Cascaded Converters Based onModel Predictive Control

A modular system of cascaded converters based on model predictive control(MPC)is proposed to meet the application requirements ofmultiple voltage levels and electrical isolation in renewable energy generation systems.The system consists of a Buck/Boost+CLLLC cascaded converter as a submodule,which is combined in series and parallel on the input and output sides to achieve direct-current(DC)voltage transformation,bidirectional energy flow,and electrical isolation.The CLLLC converter operates in DC transformer mode in the submodule,while the Buck/Boost converter participates in voltage regulation.This article establishes a suitable mathematical model for the proposed system topology,and uses MPC to control the system based on this mathematical model.Module parameters are designed and calculated,and simulation is built in MATLAB/Simulink to complete the simulation comparison experiment between MPC and traditional proportional integral(PI)control.Finally,a physical experimental platform is built to complete the physical comparison experiment.The simulation and physical experimental results prove that the control accuracy and response speed ofMPC are better than traditional PI control strategy.

Hydrodynamic Performance of An Integrated System of Breakwater and A Multi-Chamber OWC Wave Energy Converter

A multi-chamber oscillating water column wave energy converter(OWC-WEC)integrated to a breakwater is investigated.The hydrodynamic characteristics of the device are analyzed using an analytical model based on the linear potential flow theory.A pneumatic model is employed to investigate the relationship between the air mass flux in the chamber and the turbine characteristics.The effects of chamber width,wall draft and wall thickness on the hydrodynamic performance of a dual-chamber OWC-WEC are investigated.The results demonstrate that the device,with a smaller front wall draft and a wider rear chamber exhibits a broader effective frequency bandwidth.The device with a chamber-width-ratio of 1:3 performs better in terms of power absorption.Additionally,results from the analysis of a triplechamber OWC-WEC demonstrate that reducing the front chamber width and increasing the rearward chamber width can improve the total performance of the device.Increasing the number of chambers from 1 to 2 or 3 can widen the effective frequency bandwidth.

Negative Stiffness Mechanism on An Asymmetric Wave Energy Converter by Using A Weakly Nonlinear Potential Model

Salter's duck,an asymmetrical wave energy converter(WEC)device,showed high efficiency in extracting energy from 2D regular waves in the past;yet,challenges remain for fluctuating wave conditions.These can potentially be addressed by adopting a negative stiffness mechanism(NSM)in WEC devices to enhance system efficiency,even in highly nonlinear and steep 3D waves.A weakly nonlinear model was developed which incorporated a nonlinear restoring moment and NSM into the linear formulations and was applied to an asymmetric WEC using a time domain potential flow model.The model was initially validated by comparing it with published experimental and numerical computational fluid dynamics results.The current results were in good agreement with the published results.It was found that the energy extraction increased in the range of 6%to 17%during the evaluation of the effectiveness of the NSM in regular waves.Under irregular wave conditions,specifically at the design wave conditions for the selected test site,the energy extraction increased by 2.4%,with annual energy production increments of approximately 0.8MWh.The findings highlight the potential of NSM in enhancing the performance of asymmetric WEC devices,indicating more efficient energy extraction under various wave conditions.

Harmonic Impedance Modeling and Oscillation Analysis of Modular Multilevel Converter

To facilitate rapid analysis of the oscillation stability mechanism in modular multilevel converter-based high voltage direct current(MMC-HVDC)systems and streamline the simulation process for determining MMC impedance characteristics,a simplified mathematical simulation model for MMC closed-loop impedance is developed using the harmonic state space method.This model considers various control strategies and includes both AC-side and DC-side impedance models.By applying a Nyquist criterion-based impedance analysis method,the stability mechanisms on the AC and DC sides of the MMC are examined.In addition,a data-driven oscillation stability analysis method is also proposed,leveraging a global sensitivity algorithm based on fast model results to identify key parameters influencing MMC oscillation stability.Based on sensitivity analysis results,a parameter adjustment strategy for oscillation suppression is proposed.The simulation results from the MATLAB/Simulinkbased MMC model validate the effectiveness of the proposed method.

Extracellular vesicles and angiotensin-converting enzyme 2 in COVID-19 disease

Extracellular vesicles(EVs)are membranous vesicular structures released from almost all eukaryotic cell types under different physiological or pathological conditions.Growing evidence demonstrates that EVs can serve as mediators of intercellular communication between donor and recipient cells or microorganism-infected and noninfected cells.Coronavirus disease 2019(COVID-19)disease is caused by infection of the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)of host cells in the respiratory system and various extra-pulmonary tissue/organs,resulting in complications of multiple organ systems.As the cell surface receptor,angiotensin-converting enzyme 2(ACE2)mediates cellular entry of SARS-CoV-2 into the host cells in patients with COVID-19.Recent studies have found that ACE2 can be released with EVs,which have been shown to interfere with the entry of the virus into host cells and thus may be involved in COVID-19 pathophysiology.In addition,ACE2,neprilysin(NEP),and thimet oligopeptidase(TOP)are the key enzymes that regulate angiotensin metabolism by converting angiotensin II or angiotensin I to angiotensin 1-7,the latter of which has protective effects in counterbalancing the harmful effects of angiotensin II in COVID-19 disease.This review summarizes the recent research progress regarding EV-associated ACE2,NEP,and TOP and the perspectives of their potential involvement in the pathophysiology of COVID-19 disease.

Tomographic inversion of OBS converted shear waves:case study of profile EW6 in the Dongsha area

Studies of converted S-wave data recorded on the ocean bottom seismometer(OBS)allow for the estimation of crustal S-wave velocity,from which is further derived the Vp/Vs ratio to constrain the crustal lithology and geophysical properties.Constructing a precise S-wave velocity model is important for deep structural research,and inversion of converted S-waves provides a potential solution.However,the inversion of the converted S-wave remains a weakness because of the complexity of the seismic ray path and the inconsistent conversion interface.In this study,we introduced two travel time correction methods for the S-wave velocity inversion and imaged different S-wave velocity structures in accordance with the corresponding corrected S-wave phases using seismic data of profile EW6 in the northeastern South China Sea(SCS).The two inversion models show a similar trend in velocities,and the velocity difference is<0.15 km/s(mostly in the range of 0–0.1 km/s),indicating the accuracy of the two travel time correction methods and the reliability of the inversion results.According to simulations of seismic ray tracing based on different models,the velocity of sediments is the primary influencing factor in ray tracing for S-wave phases.If the sedimentary layer has high velocities,the near offset crustal S-wave refractions cannot be traced.In contrast,the ray tracing of Moho S-wave reflections was not significantly impacted by the velocity of the sediments.The two travel time correction methods have their own advantages,and the application of different approaches is based on additional requirements.These works provide an important reference for future improvements in converted S-wave research.

Extreme Responses of An Integrated System with A Semi-Submersible Wind Turbine and Four Torus-Shaped Wave Energy Converters in Different Survival Modes

Offshore wind power is a kind of important clean renewable energy and has attracted increasing attention due to the rapid consumption of non-renewable energy.To reduce the high cost of energy,a possible try is to utilize the combination of wind and wave energy considering their natural correlation.A combined concept consisting of a semi-submersible wind turbine and four torus-shaped wave energy converters was proposed and numerically studied under normal operating conditions.However,the dynamic behavior of the integrated system under extreme sea conditions has not been studied yet.In the present work,extreme responses of the integrated system under two different survival modes are evaluated.Fully coupled time-domain simulations with consideration of interactions between the semi-submersible wind turbine and the torus-shaped wave energy converters are performed to investigate dynamic responses of the integrated system,including mooring tensions,tower bending moments,end stop forces,and contact forces at the Column-Torus interface.It is found that the addition of four tori will reduce the mean motions of the yaw,pitch and surge.When the tori are locked at the still water line,the whole integrated system is more suitable for the survival modes.

Evaluation of angiotensin converting enzyme insertion/deletion, alpha adducin (ADD1) G460W, and IL-10 gene polymorphisms, and determination of prognostic effects in idiopathic sudden sensorineural hearing loss

Objective:The aim of this study was to examine angiotensin converting enzyme(ACE)insertion/deletion,alpha adducin,and interleukin-10(IL-10)gene polymorphisms(GPs)in terms of both idiopathic sudden sensorineural hearing loss(ISSNHL)risk and their potential prognostic effects.Methods:The study group consisted of 70 patients and the control group consisted of 50 patients.Venous blood samples were analyzed for relevant GPs via kompetitive allele-specific polymerase chain reaction.Age,sex,affected side,tinnitus,and vertiginous symptom status,number of days between symptom onset and hospital admission,pure tone audiometry results at admission and after treatment were included in the study.Data were compared statistically.Results:The D allele of ACE insertion/deletion GP was significantly more frequent in patients with ISSNHL than in the control group(p=0.032).II genotype was associated with a reduced risk of ISSNHL(p=0.036).The amount of hearing loss was significantly higher in patients with the TT genotype(p=0.027)and T allele of the IL-10 GP(p=0.035)than in the patients without this allele.Severe hearing loss was a poor prognostic factor(p=0.008).Conclusions:The D allele of ACE insertion/deletion GP may be involved in the ISSNHL etiology.Due to the association of this allele with occlusive vascular pathologies,ischemia is believed to be a common pathway in the etiopathogenesis of ISSNHL.