急性脑卒中患者血浆Hcy与脑白质疏松、PSCAD的相关性分析

目的探讨急性脑卒中患者血浆同型半胱氨酸(Hcy)与脑白质疏松、卒中后焦虑抑郁共病(PSCAD)的关系。方法回顾性分析270例急性脑卒中患者临床资料,按照脑白质疏松(LA)严重程度分为轻度LA组和中重度LA组,按照是否存在PSCAD状态分为PSCAD组和非PSCAD组,所有患者均于入院后第2天抽取肘静脉血检测血浆Hcy水平,分析血浆Hcy水平与LA、PSCAD的关系。结果中重度LA组患者年龄、高血压、吸烟、中重度梗死及血浆Hcy水平高于轻度LA组(P<0.05),PSCAD组高血压、饮酒、基底节区和额叶区梗死、中重度梗死及血浆Hcy水平高于非PSCAD组(P<0.05);年龄、高血压及血浆Hcy水平是中重度LA的独立危险因素(P <0.05),饮酒、血浆Hcy水平是PSCAD的独立危险因素(P <0.05)。血浆Hcy水平与LA、PSCAD呈正相关(P<0.05)。结论通过检测血浆Hcy水平能够在一定程度上反应LA病情和焦虑抑郁程度,为临床治疗和预后监测提供依据。

Olfactory ensheathing cell transplantation alters the expression of chondroitin sulfate proteoglycans and promotes axonal regeneration after spinal cord injury

Cell transplantation is a potential treatment for spinal cord injury. Olfactory ensheathing cells(OECs) play an active role in the repair of spinal cord injury as a result of the dual characteristics of astrocytes and Schwann cells. However, the specific mechanisms of repair remain poorly understood. In the present study, a rat model of spinal cord injury was established by transection of T10. OECs were injected into the site, 1 mm from the spinal cord stump. To a certain extent, OEC transplantation restored locomotor function in the hindlimbs of rats with spinal cord injury, but had no effect on the formation or volume of glial scars. In addition, OEC transplantation reduced the immunopositivity of chondroitin sulfate proteoglycans(neural/glial antigen 2 and neurocan) and glial fibrillary acidic protein at the injury site, and increased the immunopositivity of growth-associated protein 43 and neurofilament. These findings suggest that OEC transplantation can regulate the expression of chondroitin sulfate proteoglycans in the spinal cord, inhibit scar formation caused by the excessive proliferation of glial cells, and increase the numbers of regenerated nerve fibers, thus promoting axonal regeneration after spinal cord injury. The study was approved by the Animal Ethics Committee of the Medical College of Xi'an Jiaotong University, China(approval No. 2018-2048) on September 9, 2018.

Minimally invasive treatment of hepatic hemangioma by transcatheter arterial embolization combined with microwave ablation:A case report

BACKGROUND Hepatic hemangioma is the most common benign tumor of the liver.However,patients with large hemangiomas that cause compression symptoms or that are at risk of rupture may need further intervention.It is necessary to explore additional minimally invasive and personalized treatment options for hemangiomas.CASE SUMMARY A 47-year-old woman was diagnosed with a right hepatic hemangioma for more than 10 years.Abdominal contrast-enhanced computed tomography(CT)and contrast-enhanced ultrasound revealed that there was a large hemangioma in the right liver,with a size of approximately 95 mm×97 mm×117 mm.Due to the patient's refusal of surgical treatment,hepatic artery embolization was performed in the first stage.After 25 d of liver protection treatment,the liver function indexes decreased to normal levels.Then,ultrasound-guided microwave ablation of the giant hepatic hemangioma was performed.Ten days after the treatment,hepatobiliary ultrasonography showed that the hemangioma of the right liver was smaller than the previous size(the volume was reduced by approximately 30%).Then the patient was discharged from the hospital.One year after discharge,CT showed that the hepatic hemangioma had shrunk by about 80%CONCLUSION Transcatheter arterial embolization combined with microwave ablation is a safe and effective minimally invasive treatment for hepatic hemangioma.

Three-dimensional numerical simulation of wave interaction with perforated quasi-ellipse caisson

The finite difference method and the volume of fluid （VOF） method were used to develop a three-dimensional numerical model to study wave interaction with a perforated caisson. The partial cell method was adopted to solve this type of problem for the first time. The validity of the present model, with and without the presence of caisson structures, was examined by comparing the model results with experimental data. Then, the numerical model was used to investigate the effects of various wave and structure parameters on the wave force and wave runup of the perforated quasi-ellipse caisson. Compared with the solid quasi-ellipse caisson, the wave force on the perforated quasi-ellipse caisson is significantly reduced with increasing porosity of the perforated quasi-ellipse caisson. Furthermore, the perforated quasi-ellipse caisson can also reduce the wave runup, and it tends to decrease with the increase of the porosity of the perforated quasi-ellipse caisson and the relative wave height.

Synthesis and thermoelectric properties of Nd-single filled p-type skutterudites

We report the synthesis of Nd-filled and Fe substituted p-type Ndx Fe（3.2）Co（0.8）Fe（3.2）Co（0.8）Sb（12）（x=0.5,0.6,0.7,0.8,and 0.9）skutterudites by the solid-state reaction method.The influences of Nd filler on the electrical and thermal transport prop-erties are investigated in a temperature range from room temperature to 850 K.A lowest lattice thermal conductivity of 0.88 W·m^-1·K^-1 is obtained in Nd0.8Fe（3.2）Co（0.8）Fe（3.2）Co（0.8）Sb（12）at 673 K,which results from the localized vibration modes of fillers and the increase of grains boundaries.Meanwhile,the maximum power factor is 2.77 m W·m^-1·K^-2 for the Nd（0.9）Fe（3.2）Co（0.8）Fe（3.2）Co（0.8）Sb（12）sample at 668 K.Overall,the highest dimensionless figure of merit z T=0.87 is achieved at 714 Kfor Nd（0.9）Fe（3.2）Co（0.8）Fe（3.2）Co（0.8）Sb（12）.

Adult duodenal intussusception with horizontal adenoma: A rare case report

BACKGROUND Adult duodenal intussusception rarely occurs,and the majority of duodenal adenomas are located in the descending part of the duodenum.Therefore,adenomas in the horizontal part of the duodenum presenting as duodenal intussusception in adults are extremely rare.CASE SUMMARY A 36-year-old man complained of abdominal pain for 13 d.Blood analysis showed anemia.Magnetic resonance cholangiopancreatography and computed tomography revealed a tumor in the horizontal part of the duodenum as the main finding,leading to duodeno-duodenal intussusception.No obvious abnormalities were found on endoscopy or upper gastrointestinal radiography.He was diagnosed with duodenal intussusception secondary to duodenal adenoma.Laparotomy showed duodeno-duodenal intussusception and a tumor in the horizontal part of the duodenum near the ascending part.Postoperative pathology revealed tubular-villous adenoma with low-grade glandular intraepithelial neoplasia(local high-grade intraepithelial neoplasia).He was discharged without complications.CONCLUSION This case highlights that rational use of computed tomography,magnetic resonance cholangiopancreatography,endoscopy and upper gastrointestinal radiography for preoperative diagnosis and timely surgery is an effective strategy for the treatment of adult duodenal intussusception with duodenal masses.

Roles of Cu doping in YbZn_(2)Sb_(2) for thermoelectric performance enhancement

Recent research shows that increasing the carrier density after orbital alignment in AZn_(2)Sb_(2) (A=Ca,Yb,Eu,Sr,Mg)Zintl compounds yields remarkable results with regard to enhanced thermoelectric performance.However,research on carrier density increase via doping in these compounds is limited.In this study,we introduced Cu into the Zn sites in YbZn_(2)Sb_(2) and examined the thermoelectric properties.

Global cavitation and hydrodynamic characteristics of a composite propeller in non-uniform wake

The composite propeller has attracted much interest due to its excellent mechanical properties such as high specific stiffness and high specific strength,hence there is an increasing interest in utilizing the composite materials to improve the hydrodynamic and structural performance of marine propellers.The objective of this paper is to study the cavitation performance of composite propellers based on the unsteady simulation method considering the cavitation-composite structure interaction.The typical cavitation patterns around the composite propeller are studied,which include blade sheet cavitation and tip vortex cavitation.The unsteady flow characteristics of tip vortex cavitation and structural dynamic response of composite propeller are studied,and the mechanism of composite propeller for the cavitation suppression and efficiency improvement is revealed.The results show that compared with rigid propellers,composite propellers have smaller cavity volume and higher propulsion efficiency under the same conditions.The unsteady cavitating flow characteristics under non-uniform wake are periodic,and the phase lag of hydrodynamic coefficients of composite propeller can be observed compared with that of the rigid propeller.The bending-torsional coupling deformation of the composite propeller makes the pressure pulsation of the flow field gentler,which reduces the influence of the cavitation load on the composite propeller.

A review of transient flow structure and unsteady mechanism of cavitating flow

The flow structure and the unsteady mechanism of the unsteady cavitating flow are reviewed in this paper. The flow patterns and structures in different cavitation regime, for the attached cavitation and the vortical cavitation, are shown with both the visualization and the quantitative information. The attached cavitating flow around the Clark-Y hydrofoil and the vortical cavitating flow around the Tulin hydrofoil are considered. In particular, the phenomena such as the large-scale vortex structure and the re-entrant flow associated with the cloud cavitation, and the cavitating vortex street's forming and crumbling are described. The evolution of the cavitation structure in the transient sheet/cloud cavity forming, along with the cavity collapse induced by the re-entrant flow and the shock wave propagation are discussed. The perspective future research of higher fidelity simulations, and the accurate identifications of the cavitating vortex structure is commented.

Cavitation vortex dynamics of unsteady sheet/cloud cavitating flows with shock wave using different vortex identification methods

Cavitation is a complex multiphase flow phenomenon with an abrupt transient phase change between the liquid and the vapor, including multiscale vortical motions. The transient cavitation dynamics is closely associated with the evolution of the cavitation vortex structures. The present paper investigates the cavitation vortex dynamics using different vortex identification methods, including the vorticity method, the Q criterion method, the Omega method (Ω), the method and the Rortex method. The Q criterion is an eigenvalue-based criterion, and in the Ω method, the parameter is normalized, is independent of the threshold value and in most conditions Ω= 0.52 . The Rortex method is based on an eigenvector-based criterion. Numerical simulations are conducted using the implemented compressible cavitation solver in the open source software OpenFOAM for the sheet/cloud cavitating flows around a NACA66 (mod) hydrofoil fixed at a = 6°,= 1.25 and Re = 7.96 × 10^5 . The flow is characterized by the alternate interactions of the re-entrant flow and the collapse induced shock wave. Results include the vapor structures and the vortex dynamics in the unsteady sheet/cloud cavitating flows, with emphasis on the vortex structures in thecavitation region, the cavity interface, the cavity closure, the cavity wakes, and the foil wakes with the shedding cavity. The comparisons of the various methods, including that the vorticity method, the Q criterion method, the Ω method, the λ2 method and the Rortex method, show the performances of different methods in identifying the cavitation vortex structures. Generally, during the attached cavity growth stage, the Q criteria can well predict the vortex structures in the cavitation region and at the foil trailing edge in the pure liquid region, while with the Ω method and the Rortex method, the vortex structures outside the attached cavity and on the foil pressure side can also be predicted. The λ2 method can well predict the vortex structures in the cavity closure region. During the re-entrant jet development stage, the vortex structures in the re-entrant jet region is weak. During the cavity cloud shedding stage, the vortex dynamics at the foil leading edge covered by newly grown cavity sheet is different from that during the attached cavity sheet growth stage. During the shock wave formation and propagation stage, strong vortex structures with both the size and the strength are observed owing to the cavity cloud shedding and collapse behavior. The influence of the small parameter ε in the Ω method on the cavitation vortex identification is discussed.

Ultra-fine Cu clusters decorated hydrangea-like titanium dioxide for photocatalytic hydrogen production

Hydrogen,with the merits of zero emissions and high energy density,is one of the promising green energy sources.Seeking for high efficiency and low-cost catalysts is one of the key issues for hydrogen evolution and its practical applications.Nano-structured metal cocatalysts are widely used to improve the photocatalytic performance via surface electronic structure/properties optimization of the catalyst.Herein,we report ultra-fine(*1 nm)Cu clusters decorated hydrangea-like TiO_(2)systems for photocatalytic hydrogen evolution.The pristine hydrangea-like TiO_(2)support shows a promising performance of hydrogen evolution(1.8 mmol·h^(-1)·g^(-1)),which is*10.7 times higher than that of the commercial P25(168 lmol·h^(-1)·g^(-1)).After ultra-fine Cu clusters decoration,a maximal hydrogen evolution performance(3.7 mmol·h^(-1)·g^(-1))is achieved in the optimized system 6Cu–TiO_(2)(6 wt%).Experimental and theoretical studies demonstrate that the ultra-fine Cu clusters decoration could promote the charge separation and transfer process effectively.The Cu clusters also act as reaction sites for reduction of H_(2)O to H2.These results are of great importance for the study of Cu-based co-catalyst systems and also shed light on the development of other non-noble metal co-catalysts in photocatalysis hydrogen evolution.

Optimizing thermoelectric properties of BiSe through Cu additive enhanced effective mass and phonon scattering

Known as a weak topological insulator(TI),BiSe structurally exhibits alternating stacks of quantum spin Hall bilayer("Bi_(2)")and three-dimensional TI layer("Bi_(2)Se_(3)").The low lattice thermal conductivity of BiSe due to the presence of Bi2 bilayers promises potentially good thermoelectric performance.Herein,the thermoelectric properties of nominal Bi_(1-x)Cu_(x)Se samples were studied as the functions of the content of Cu additive and temperature.It is found that Cu additives in BiSe(1)profoundly affect the texture of densified polycrystalline samples by inclining the crystallographic c-axis parallel toward the pressure direction in the densification process,(2)increase considerably the effective mass and thus the Seebeck coefficient,and(3)yield point defects and Cu-Se secondary phases that effectively scatter heat-carrying phonons.As a result,the optimized electrical and thermal properties yield a thermoelectric figure of merit of zT~0.29 in Bi_(1-x)Cu_(x)Se(x=0.03)sample at 467 K in parallel to the pressure direction and a zT~0.20 at 468 K in the perpendicular direction.

Numerical studies of the hydrodynamic damping of a vibrating hydrofoil in torsional mode

The vortex-induced vibration may lead to a premature failure of hydraulic mechanical systems,especially under the resonance condition in the torsional mode.To predict the structural fatigue life,a careful consideration of the dynamic response to the hydraulic excitations is essential in the design phase.This study focuses on the numerical investigation of the relationship between the flow velocity,the added mass and the hydrodynamic damping,particularly,with respect to a Donaldson-type hydrofoil,vibrating in the first torsional mode.A two-way fluid-structure interaction(FSI)method is used to predict above two parameters.The flow velocity is in the range of 0 m/s-20m/s.To evaluate the hydrodynamic damping ratio,an identification method is proposed,based on a modified version of the logarithmic decay method.The relative deviations of the simulated natural frequencies and hydrodynamic damping ratios as compared with the experimental data for the first torsional modes,are within 8.1%and 16.6%,respectively.The analysis results show that the added mass coefficient for the first torsional mode is in the range of 1.59-1.86,and is around 44%of that for the first bending mode.The trends of the boundary layer thickness and the wake width against the reduced velocity are found to be opposite to that of the hydrodynamic damping ratio.The theoretical equation for predicting the hydrodynamic damping ratio is modified,which is shown to be more reliable due to its consideration of the velocity independent hydrodynamic damping phase.

Enhanced thermoelectric performance of ternary compound Cu_(3)PSe_(4)by defect engineering

The diamond-like compound Cu_(3)PSe_(4)with low lattice thermal conductivity is deemed to be a promising thermoelectric material,which can directly convert waste heat into electricity or vice versa with no moving parts and greenhouse emissions.However,its performance is limited by its low electrical conductivity.In this study,we report an effective method to enhance thermoelectric performance of Cu_(3)PSe_(4)by defect engineering.It is found that the carrier concentrations of Cu_(3-x)PSe_(4)(x=0,0.03,0.06,0.09,0.12)compounds are increased by two orders of magnitude as x>0.03,from 1×10^(17)to 1×10^(19)cm^(-3).Combined with the intrinsically low lattice thermal conductivities and enhanced electrical transport performance,a maximum zT value of 0.62 is obtained at 727 K for x=0.12 sample,revealing that Cu defect regulation can be an effective method for enhancing thermoelectric performance of Cu_(3)PSe_(4).

Measurement and prediction of cavitating flow-induced vibrations

The objective of this paper is to investigate the unsteady cavitation behaviors and the corresponding cavitating flow-induced vibrations. Results are presented for the modified NACA66 hydrofoils made of stainless steel and POM Polyacetate respectively at Re= 6.0×105for various cavitation regimes. The high-speed camera and the single point laser Doppler vibrometer(LDV) are used to observe the transient cavitating flow patterns and measure the vibration velocities. The results showed that the vibration amplitude increases dramatically for the cloud cavitation due to the development of large-scale cloud cavity. The main flow-induced frequencies, which are in accordance with the cavity shedding frequency, decrease with the decrease of the cavitation number. As for the effect of the hydroelastic response on the vibration behavior, the lift coefficient for the POM Polyacetate hydrofoil fluctuates more significantly with a larger mean value than that for the stainless steel hydrofoil. Compared with the vaporous cavity along the suction side of the stainless steel hydrofoil, the cavity for POM Polyacetate hydrofoil appears to be fragmentized. The main vibration frequencies for the POM Polyacetate hydrofoil are larger than that for the stainless steel hydrofoil, with the chaotic hydroelastic response with high frequency.

On study of non-spherical bubble collapse near a rigid boundary

This paper applies numerical methods to investigate the non-spherical bubble collapse near a rigid boundary. A three-dimensional model, with the mass conservation equation reformulated for considering the compressibility effect, is built to deal with the coupling between the pressure and the flow velocity in the momentum and energy equations and to simulate the temporal evolution of the single bubble oscillation and its surrounding flow structure. The investigations focus on the global bubble patterns and its schlieren contours, as well as the high-speed jet accompanied when the bubble collapses and the counter jet is generated in the rebound stage. The results show that the robust pressure waves emitted due to the bubble collapse lead to substantial changes of the flow structures around the bubble, especially the formation of the counter jet generated in the rebound stage. Furthermore, compared with the high-speed jet when the bubble collapses, the counter jet in the rebound stage emits the momentum several times greater in the magnitude and in diametrically opposite direction at the monitoring point.

Experimental Investigation of fluid-structure interaction of composite hydrofoils in cavitating flow

This paper experimentally studies the cavitating fluid-structure interaction of composite hydrofoils with different ply angles.The synchronous measurement system with high-speed camera and for laser Doppler vibrometer(LDV),the feedback pressure regulation system,and the flow rate control system are established.The experimental results of the cavitation evolution show that,compared with the rigid hydrofoil,the composite hydrofoils with+45°ply angle and 0°ply angle accelerate the cavitation inception,and the composite hydrofoil with−45°ply angle delays the cavitation inception.At the same cavitation number,the cloud cavitation of the+45°laminated hydrofoil is the most severe,followed by that of the 0°laminated hydrofoil,and that of the−45°laminated hydrofoil is relatively weak and close to that of the rigid hydrofoil.The analyses of the structural vibration of the composite hydrofoils in different cavitation stages show that the three composite hydrofoils have no significant vibration at the incipient cavitation and the supercavitation,but relatively significant vibration is observed in the sheet and cloud cavitation.The vibration amplitude of the composite hydrofoil with+45°ply angle is the largest,followed by those of the−45°,0°laminated hydrofoils.In the sheet cavitation,the dominant frequencies of the structural vibration velocity of the+45°laminated hydrofoil and the−45°laminated hydrofoil are the first and second modal frequencies,but no explicit dominant frequency is observed for the 0°laminated hydrofoil.In the cloud cavitation,the dominant frequencies of the three composite hydrofoils mainly include the first modal frequency,the second modal frequency,and the cavity shedding frequency.

Experimental investigation of regular wave propagation over an idealized reef model

The wave transformation over the deep-sea coral reefs is an essential issue in the analysis of the reef ecosystem and the design of large reef-top structures.Extensive wave flume experiments are conducted to investigate the wave transformation processes over an idealized reef model.Detailed measurements of the wave height,the wave set-up and the wave-generated flow on the reef-top are made with and without the reef-top structure at various submerged depths and under different wave conditions.It is found that the reef-top structure has a significant influence on the wave breaking,the wave set-up and the wave-generated flow.The wave set-up increases with the increasing wave height and the decreasing submergence depth.However,the relationship between the wave set-up and the wave period is complex,influenced by the reef-top structure.