Type Synthesis of Fully Decoupled Three Translational Parallel Mechanism with Closed-Loop Units and High Stifness

In order to solve the problem of weak stifness of the existing fully decoupled parallel mechanism, a new synthesis method of fully decoupled three translational (3T) parallel mechanisms (PMs) with closed-loop units and high stifness is proposed based on screw theory. Firstly, a new criterion for the full decoupled of PMs is presented that the reciprocal product of the transmission wrench screw matrix and the output twist screw matrix of PMs is a diagonal matrix, and all elements on the main diagonal are nonzero constants. The forms of the transmission wrench screws are determined by the criterion. Secondly, the forms of the actuated and unactuated screws can be obtained according to their relationships with the transmission wrench screws. The basic decoupled limbs are generated by combination of the above actuated and unactuated screws. Finally, a closed-loop units construction method is investigated to apply the decoupled mechanisms in a better way on the high stifness occasion. The closed-loop units are constructed in the basic decoupled limbs to generate a high-stifness fully decoupled 3T PM. Kinematic and stifness analyses show that the Jacobian matrix is a diagonal matrix, and the stifness is obviously higher than that of the coupling mechanisms, which verifes the correctness of the proposed synthesis method. The mechanism synthesized by this method has a good application prospect in vehicle durability test platform.

A Compact MEMS-Based Optical Scanning System with Large Field of View for Lidars

In this work, a design of a compact optical MEMS-based lidar scanning system with a large field of view (FOV) and small distortion is presented. The scanning system applies an off-axis structure and the length of the system can be reduced to about 10 cm in an optimized way. Simulation results show that a large FOV is achieved under a uniform scanning scheme. In addition, the spot size less than 20 cm at distance of 100 m is also realized. The optical scanning system can be used for the vehicle-mounted Lidar.

Long-term anodal block stimulation at sacral anterior roots promoted recovery of neurogenic bladder function in a rabbit model of complete spinal cord injury

A complete spinal cord injury model was established in experimental rabbits using the spinal cord clip compression method. Urodynamic examination was performed 2 weeks later to determine neurogenic bladder status. The rabbits were treated with anodal block stimulation at sacral anterior roots for 4 weeks. Electrical stimulation of sacral anterior roots improved urodynamic parameters of neurogenic bladder in rabbit models of complete spinal cord injury, effectively promoted urinary function, and relieved urinary retention. Immunohistochemistry results showed that a balance was achieved among expression of muscarinic receptor subunits M2, M3, ATP-gated ion channel P2X3 receptors, and 132-adrenergic receptor, and nerve growth factor expression decreased. These results suggested that long-term sacral anterior root stimulation of anodal block could＇be used to treat neurogenic bladder in a rabbit model of complete spinal cord injury.

Template-free synthesis of hollow TiO2 nanospheres supported Pt for selective photocatalytic oxidation of benzyl alcohol to benzaldehyde

Heterogeneous photocatalytic system are widely applied to degrade organic pollutants or converse into high value-added chemicals. Both environmental and energy aspects should be considered to improve these chemical processes, favoring reaction conditions that involve room temperature and ambient O2 pressure. In the present work, hollow titanium dioxide nanospheres were fabricated via template-free method. The prepared samples were characterized by X-ray diffraction, N2 adsorption–desorption isotherms, transmission electron microscopy, and X-ray photoelectron spectroscopy. The photocatalytic activity was evaluated by photocatalytic oxidation of benzyl alcohol to benzaldehyde with visible light under atmospheric pressure at room temperature. The designed hollow structure(2%Pt–TiO2–5) not only exhibited a very high surface area,but also promoted photonic behavior and multiple light scattering, which as an efficient photocatalyst performed moderate conversion(about 20%) and high selectivity(> 99%) for oxidation of benzyl alcohol to benzaldehyde at room temperature with visible light in solvent of toluene.This work suggests that both hollow structure and Pt nanoparticles have great potential for execution of oxidative transformations under visible light.

我国家庭养猪农场发展趋势浅析

自20世纪80年代起至2014年,一直是我国养猪业快速发展的黄金时间。在这个期间,我国的养猪业完成了从农耕附属行业向一个独立自主行业的转变,完成了初步的规模化和集约化化之路;同时也基本满足了人民生活水平不断提升后,对高质量肉制品的需求。但是新的矛盾也不断地呈现出来,比如,虽然生猪基本量供应满足了市场需求,但是整个行业的质量和生产效率依然远远落后于发达国家,低效率生产带来人猪争地的环境压力,高抗生素使用量带来食品安全压力,还有生物安全压力和“用人荒”等问题。自2014年起,我国养猪业进入一个新的发展阶段,那就是生产精细化。

Correlation between clinicopathological parameters of lung adenocarcinoma and lymph node metastasis

Objective The aim of the study was to study the correlation between the clinicopathological parameters of lung adenocarcinoma and lymph node metastasis and identify the risk factors of lymph node metastasis.Methods The data of 258 patients with postoperative lung adenocarcinoma(mainly based on their pathological data)were collected and analyzed,and their basic information was counted.Results Maximum tumor diameter was found to be an independent risk factor for lymph node metastasis.The larger the maximum diameter of the tumor in patients with lung adenocarcinoma,the higher the likelihood of lymph node metastasis.Solid predominant adenocarcinoma with mucin production is as an independent risk factor for superior mediastinal and subcarinal lymph node metastasis.Primary adenocarcinomas in the lower lobe of the lung may have a higher rate of lymph node metastasis than those in the upper lobe.Conclusion The known pathological subtypes of lung adenocarcinoma can be used for the prediction of lymph node metastasis in various regions and guide the dissection of lymph nodes that would improve patients’prognosis.

Analysis on the Effects of Shensong Yangxin Capsules and Amiodarone on Heart Rate Variability Indices and Inflammatory Factors in Patients with Arrhythmia

Objective:To study the effects of Shensong Yangxin capsules and amiodarone on heart rate variability indexes and inflammatory factors in the treatment of patients with arrhythmia.Methods:The research subjects were selected patients with arrhythmia admitted in our hospitaFs department from October 2018 to October 2019,and a total of 70 patients were divided into two groups.35 subjects in the control group were treated with amiodarone alone,and 35 subjects in the observation group were treated with Shensongyangxin capsule in combination with amiodarone for comparisons in treatment effects,heart rate variability indices,inflammatory factors,and adverse reactions.Results:After observation,the treatment efficiency in the observation group was higher than that in the control group(P<0.05).Before treatment,there was no difference in heart rate variability indices between the two groups(P>0.05),after treatment,the improvement in patients of the observation group was better than that of the control group(P<0.05).After treatment,the inflammatory factors of the two groups of patients decreased,and the indicators of the observation group were comparably lower than those of the control group(P<0.05).In the comparison of adverse reactions,the observation group showed a lower incidence of adverse reactions after treatment than the control group(P<0.05).Conclusion:In the treatment of patients with arrhythmia,the combined use of Shensong Yangxin capsules and amiodarone has more significant therapeutic effects,which can effectively improve the patient's heart rate variability indices,reduce the inflammatory factors,and relieve the symptoms in patients.The incidence of adverse reactions is low and the safety is quite high,therefore it has great value in clinical applications.

Sex-biased single-cell genetic landscape in mice with autism spectrum disorder

Autistic spectrum disorder(ASD)is a male-biased,heterogeneous neurodevelopmental disorder that affects approximately 1%e2%of the population.Prenatal exposure to valproic acid(VPA)is a recognized risk factor for ASD,but the cellular and molecular basis of VPA-induced ASD at the single-cell resolution is unclear.Here,we aim to compare the cellular and molecular differences in the hippocampus between male and female prenatal mice with ASD at the single-cell transcriptomic level.The transcriptomes of more than 45,000 cells are assigned to 12 major cell types,including neurons,glial cells,vascular cells,and immune cells.Cell type-specific genes with altered expression after prenatal VPA exposure are analyzed,and the largest number of differentially expressed genes(DEGs)are found in neurons,choroid plexus epithelial cells,and microglia.In microglia,several pathways related to inflammation are found in both males and females,including the tumor necrosis factor(TNF),nuclear factor kappa B(NF-kB),toll-like receptor(TLR),and mitogen-activated protein kinase(MAPK)signaling pathways,which are important for the induction of autistic-like behavior.Additionally,we note that several X-linked genes,including Bex1,Bex3,and Gria3,were among the male-specific DEGs of neurons.This pioneering study describes the landscape of the transcriptome in the hippocampus of autistic mice.The elucidation of sexual differences could provide innovative strategies for the prevention and treatment of ASD.

Tau Accumulation in the Spinal Cord Contributes to Chronic Inflammatory Pain by Upregulation of IL-1βand BDNF

Microtubule-associated protein Tau is responsible for the stabilization of neuronal microtubules under normal physiological conditions.Much attention has been focused on Tau’s contribution to cognition,but little research has explored its role in emotions such as pain,anxiety,and depression.In the current study,we found a significant increase in the levels of p-Tau(Thr231),total Tau,IL-1β,and brain-derived neurotrophic factor(BDNF)on day 7 after complete Freund's adjuvant(CFA)injection;they were present in the vast majority of neurons in the spinal dorsal horn.Microinjection of Mapt-shRNA recombinant adeno-associated virus into the spinal dorsal cord alleviated CFA-induced inflammatory pain and inhibited CFA-induced IL-1βand BDNF upregulation.Importantly,Tau overexpression was sufficient to induce hyperalgesia by increasing the expression of IL-1βand BDNF.Furthermore,the activation of glycogen synthase kinase 3 beta partly contributed to Tau accumulation.These findings suggest that Tau in the dorsal horn could be a promising target for chronic inflammatory pain therapy.

LH-Nts Neurons Regulate VTA Calcium Dynamics Via Releasing GABA and Nts

The peripheral and central nervous systems have numerous examples of two or more neuroactive products co-existing in the same neuron[1],which can simultaneously be released as both fast-acting neurotransmitters and slow-acting regulatory neuropeptides[2].For example,neurons in the lateral hypothalamus(LH)release both irritant neurotensin(Nts)and inhibitory-aminobutyric acid(GABA),two counterproductive substances[3].LH-Nts neurons project to the ventral tegmental area(VTA)and form synaptic connections with dopamine(DA)neurons to regulate reward[4-6].More critically,VTA-DA neurons express the Nts receptor Ntsrl and play a crucial role in cognition,anesthesia,reward,and disgust[4,7,8].Nevertheless,a mechanistic understanding of how stimulation and inhibition work together to control the output of neural circuits remains unclear.It is very difficult to selectively isolate these signaling pathways in cell and circuit-specific manners.

Insight into the growth mechanism of black phosphorus

Two-dimensional(2D)black phosphorus(BP)has attracted great attention in recent years in fundamental research as well as optoelectronics applications.The controllable synthesis of high-quality BP is vital to the investigation of its intrinsic physical properties and versatile applications.Originally,BP was mostly synthesized under high temperatures and pressures.Subsequently,metal flux,wet chemical and chemical vapor transport(CVT)methods had been appeared successively.The pulsed laser deposition(PLD)and CVT methods have been used to prepare high-quality BP thin films on silicon substrates,which is significant for its monolithic integration and practical applications.To meet the demand of the scalable applications of BP,the direct preparation of BP films on dielectric substrates that avoids additional transfer process,is crucial to high-performance device implementation.In this review,the growing methods and corresponding mechanisms of BP are summarized and analyzed.Meanwhile,the view on the controllable growth of large-area,high-quality BP films is envisioned.

Neuronal Mechanisms Govern Glioblastoma Cell Invasion

Glioblastoma(GBM)remains one of the most aggressive malignancies;it is characterized by genetic heterogeneity and resistance to treatment.One main reason is that GBM cells(GBCs)communicate with other cells in the brain environment to support tumor progression and resist therapy[1].Tumor-associated astrocytes,for example.

Sodium-Calcium Exchanger-3 Plays Critical Roles in Pain"Wind-up"

Chronic pain,broadly described as pain lasting longer than 3 months,is a classic example of gene-environment interaction[1].A couple of types of chronic pain have also been shown to have complex heritable properties with a polygenic component[2].Quantitative Sensory Testing(QST)is a formal variant of the sensory examination,including"static"sensory profiling and"dynamic"QST.QST contributes to the prediction of vulnerable subpopulations and effective mechanisms.In addition,a deficit in dynamic QST has been proposed as a predictor of chronic pain[3].

A High Spatial Resolution FBG Sensor Array for Measuring Ocean Temperature and Depth

Exploring and understanding the ocean is an important field of scientific study.Acquiring accurate and high-resolution temperature and depth profiles of the oceans over relatively short periods of time is an important basis for understanding ocean currents and other associated physical parameters.Traditional measuring instruments based on piezoelectric ceramics have a low spatial resolution and are not inherently waterproof.Meanwhile,sensing systems based on fiber Bragg grating(FBG)have the advantage of facilitating continuous measurements and allow multi-sensor distributed measurements.Therefore,in this paper,an all-fiber seawater temperature and depth-sensing array is used to obtain seawater temperature and depth profiles.In addition,by studying the encapsulation structure of the FBG sensors,this paper also solves the problem of the measurement error present in traditional FBG sensors when measuring seawater temperature.Through a theoretical analysis and seaborne test in the Yellow Sea of China,the sampling frequency of the all-fiber seawater temperature and depth profile measurement system is 1 Hz,the accuracy of the FBG sensors reaches 0.01℃,and the accuracy of the FBG depth sensors reaches 0.1%of the full scale.The resulting parameters for these sensors are therefore considered to be acceptable for most survey requirements in physical oceanography.

Oxidation and Mechanical Properties of SiC/SiC-MoSi_2-ZrB_2 Coating for Carbon/Carbon Composites

To improve oxidation resistance of carbon/carbon （C/C） composites, a SiC/SiC-MoSi2-ZrB2 double-layer ceramic coating was prepared on C/C composites by two-step pack cementation. The phase compositions and microstructures of as-prepared multilayer coating were characterized by X-ray diffraction and scanning electron microscopy. The oxidation resistance at 1773 K and the effect of thermal shock between 1773 K and room temperature on mechanical performance of coated specimens were investigated. The results show that the SiC/SiC-MoSi2-ZrB2 coating exhibits dense structure and is composed of SiC, Si, MoSi2 and ZrB2. It can protect C/C composites from oxidation at 1773 K for more than 510 h with weight loss of 0.5%. The excellent anti-oxidation performance of the coating is due to the formation of SiO2-ZrSiO4 complex glassy film. The coating can also endure the thermal shocks between 1773 K and room temperature for 20 times with residual flexural strength of 86.1%.

SiC Nanowires Toughed HfC Ablative Coating for C/C Composites

In order to improve ablation resistance of carbon/carbon(C/C) composites,SiC nanowires were prepared on C/C composites surface in prior through chemical vapor reaction before HfC coating.SiC nanowires grew randomly and had good combination with HfC coating.SiC nanowires toughed HfC coating had lower linear and mass ablation rates than original HfC coating.The surface was much flatter and exhibited smaller cracks in center region.The ablation mechanism of HfC coating has been changed by SiC nanowires.Thicker HfO2 fused layer was formed on the surface of the toughed HfC coating,which could provide efficient protection for C/C composites.Therefore,SiC nanowires toughed HfC coating behaved in better ablation resistance.

基于硫化铅量子点和氧化锌纳米颗粒异质结的高性能柔性和宽波段光电探测器（英文）

柔性和宽波段的光电探测器在可折叠显示、光通信和环境监测等方面有潜在的应用,因而引起广泛的关注.本文基于硫化铅量子点和氧化锌纳米颗粒异质结制备了柔性光电探测器.该器件表现出从紫外光到近红外光的宽波段光电响应性能.在375nm紫外光照射下,该器件的电流开关比高达7.08×10~3.与单纯的氧化锌纳米颗粒器件相比,基于异质结的光电探测器的响应度在可见光和近红外光区间增加了三个数量级,同时维持了器件在紫外光范围内的性能不变.同时,基于异质结的器件的响应度和探测率高达4.54 AW^(-1)和3.98×10^(12)Jones.此外,所研制的柔性光电探测器在经过数百次的折叠后,仍表现出了良好的机械和电学稳定性.本工作为下一代柔性和宽波段光电子器件的研究做了一个初步探索.

Dynamics of arsenic in salt marsh sediments from Dongtan wetland of the Yangtze River estuary,China

The mobility and transformation of arsenic （As） in salt marsh sediments were investigated in Dongtan wetland of the Yangtze River estuary, China. As in surface water, pore water and the rhizosphere sediments were quantified. The microcosm incubation experiments were conducted during the flooding of the sediments to examine As dynamics that occurred during changing redox conditions. The concentrations of dissolved As in pore water （0.04--0.95 ixmol/L） were significantly greater than that in surface water （0.03-0.06 lunol/L）. Under anoxic conditions, the reactive As could be initially mobilized by the reductive dissolution of Fe（III） （hydr）oxides. Subsequently, most of the dissolved As was likely to be associated with secondary iron （hydr）oxide phases and remained in solid phases. The seasonal variability of acid volatile sulfide concentrations suggest the anoxic conditions are enhanced during summer by Spartina alterniflora compared to Phragmites australis and Scirpus mariqueter, causing a notable increase in As mobility. Generally, there was a typical variation in redox conditions with season in salt marsh sediments of Dongtan wetland, in which the dynamics of As mobility and transformation possibly were controlled by iron, and all of this could be significantly influenced by the rapid spread of S. alterniflora.

A modified forward and backward reaching inverse kinematics based incremental control for space manipulators

Forward and backward reaching inverse kinematics(FABRIK)is an efficient two-stage iterative solver for inverse kinematics of spherical-joint manipulator without the calculation of Jacobian matrix.Based on FABRIK,this paper presents an incremental control scheme for a free-floating space manipulator consists of revolute joints and rigid links with the consideration of joint constraints and dynamic coupling effect.Due to the characteristics of FABRIK,it can induce large angular movements on specific joints.Apart from that,FABRIK maps three dimensional(3D)problem into two dimensional(2D)problem by a simple geometric projection.This operation can cause infinite loops in some cases.In order to overcome these issues and apply FABRIK on space manipulators,an increments allocation method is developed to constrain the angular movements as well as to re-orient the end-effector.The manipulator is re-positioned based on the momentum conservation law.Instead of pure target position tracking,the orientation control of the end-effector is also considered.Numerical simulation is performed to testify and demonstrate the effectiveness and reliability of the proposed incremental control approach.

A Specific Peptide Vaccine Against IDH1(R132H) Glioma

Malignant tumors of the central nervous system(CNS)have the poorest prognosis among the cancers.Gliomas are the most commonly occurring tumors of the CNS[1],accounting for almost 30%of all primary brain tumors and 80%of all malignant brain tumors[2].In 2016,the World Health Organization(WHO)assigned gliomas into four grades(I-IV)based on molecular parameters and light microscopic features[3];WHO grade I is the least malignant while grade IV is the worst.Glioma cells are believed to be derived from neuroglial stem or progenitor cells,and are characterized by active growth,strong invasion and rapid migration.Based on morphological similarities to the neuroglial cell types found in the normal brain,gliomas are histologically classified into astrocytomas,oligodendrogliomas,mixed oligoastrocytic gliomas,and ependymomas.