超临界二氧化碳辅助挤出制备微孔醋酸纤维素

为了连续化制备泡孔结构良好的微孔二醋酸纤维素(CDA)材料,采用超临界二氧化碳(SC-CO_(2))辅助CDA挤出发泡,通过扫描电镜对微孔CDA材料断面形貌进行了观测,研究了CO_(2)注气量、螺杆转速和溶剂比对CDA泡孔形貌的影响,结果显示,随着CO_(2)注气量增加,泡孔密度从9.3×10^(7)cm^(-3)增加至1.04×10^(11)cm^(-3),平均泡孔直径从10.06μm减小至1.16μm;随着螺杆转速的提高,压降速率显著增加,泡孔密度从6.6×10^(7)cm^(-3)增加到了9.12×10^(10) cm^(-3),泡孔直径从28.1μm减小到了0.88μm;随着醇酮溶剂用量的增加,泡孔密度降低,并出现了泡孔合并现象。采用SC-CO_(2)辅助挤出发泡技术可以制备出含有致密泡孔结构的微孔CDA材料。

Effects of nursing care in fast-track surgery on postoperative pain, psychological state, and patient satisfaction with nursing for glioma

BACKGROUND The brain is the most complex organ in the human body.Treatment for a glioma always involves a multi-disciplinary team.Nursing care in fast-track surgery or enhanced recovery after surgery is such kind of work implemented by an interdisciplinary team to provide services to patients to improve their outcomes.AIM To explore the effects of nursing care in fast-track surgery on postoperative pain,psychological state,and patient satisfaction with nursing for glioma.METHODS From June 2018 to June 2020,138 patients who underwent operation for glioma at Cancer Hospital Affiliated to Chongqing University were selected.They were categorized into groups according to different nursing care that they received.Of them,69 patients receiving nursing care in fast-track surgery were included in an experimental group,and 69 patients receiving conventional postoperative nursing were included in a control group.Visual analogue scale was used to evaluate postoperative pain in the two groups immediately after the operation and at 3 d after the operation.Self-rating anxiety scale(SAS)and self-rating depression scale(SDS)were used to evaluate the psychological status of patients immediately after operation and on the 3rd postoperative day.A self-made satisfaction scale for patient satisfaction with nursing was used to evaluate and compare patient satisfaction with nursing between the two groups.RESULTS Time to excretion,time to out-of-bed activities,and length of hospital stay were significantly shorter in the observation group than in the control group(P<0.05).There was no significant difference in duration of operative time or intraoperative bleeding between the two groups(P>0.05).There was no significant difference in postoperative pain score between the two groups(P>0.05).The pain score was significantly lower in the observation group than in the control group at 3 d after the operation(P<0.05).There was no significant difference in postoperative SAS or SDS score between the two groups(P>0.05).SAS and SDS scores were significantly lower in the observation group than in the control group at 3 d after operation(P<0.05).The rate of patient satisfaction with nursing was 94.2%in the observation group,which was significantly higher than that(81.2%)of the control group(P<0.05).CONCLUSION Nursing care in fast-track surgery can relieve postoperative pain,anxiety,and depression,and improve patient satisfaction with nursing in patients with glioma,which is worthy of clinical application.

Thermal hazard assessment of TKX-50-based melt-cast explosive

In the present study, thermal hazards of TNT and DNAN used as the molten binder in TKX-50-based meltcast explosives were comparatively studied through accelerating rate calorimeter(ARC) and Cook-off experiments. Two kinds of ARC operation modes were performed to investigate the thermal safety performance under adiabatic conditions(HWS mode) and constant heating(CHR mode). The obtained results demonstrated that at both heating modes, DNAN/TKX-50 outperformed TNT/TKX-50 from the thermal safety point of view. However, the sensitivity to heat of the samples was reverse because of the different heating modes. In addition, the results of thermal hazard assessment obtained from the cookoff experiment complied with ARC analysis which indicated the molten binder TNT replaced by DNAN would reduce the hazard of the TKX-50 melt cast explosive. Furthermore, the results of cook-off experiments also showed that DNAN/TKX-50 outperformed TNT/TKX-50 from the aspect of thermal stability, which was consistent with the result of CHR mode because of the similar heating process.

Transcriptomic analysis of spinal cord regeneration after injury in Cynops orientalis

Cynops orientalis(C.orientalis)has a pronounced ability to regenerate its spinal cord after injury.Thus,exploring the molecular mechanism of this process could provide new approaches for promoting mammalian spinal cord regeneration.In this study,we established a model of spinal cord thoracic transection injury in C.orientalis,which is an endemic species in China.We performed RNA sequencing of the contused axolotl spinal cord at two early time points after spinal cord injury–during the very acute stage(4 days)and the subacute stage(7 days)–and identified differentially expressed genes;additionally,we performed Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses,at each time point.Transcriptome sequencing showed that 13,059 genes were differentially expressed during C.orientalis spinal cord regeneration compared with uninjured animals,among which 4273 were continuously downregulated and 1564 were continuously up-regulated.Down-regulated genes were most enriched in the Gene Ontology term“multicellular organismal process”and in the ribosome pathway at 10 days following spinal cord injury.We found that multiple genes associated with energy metabolism were down-regulated and multiple genes associated with the lysosome were up-regulated after spinal cord injury,indicating the importance of low metabolic activity during wound healing.Immune response-associated pathways were activated during the early acute phase(4 days),while the expression of extracellular matrix proteins such as glycosaminoglycan and collagen,as well as tight junction proteins,was lower at 10 days post-spinal cord injury than 4 days post-spinal cord injury.However,compared with 4 days post-injury,at 10 days post-injury neuroactive ligand-receptor interactions were no longer down-regulated,up-regulated differentially expressed genes were enriched in pathways associated with cancer and the cell cycle,and SHH,VIM,and Sox2 were prominently up-regulated.Immunofluorescence staining showed that glial fibrillary acidic protein was up-regulated in axolotl ependymoglial cells after injury,similar to what is observed in mammalian astrocytes after spinal cord injury,even though axolotls do not form a glial scar during regeneration.We suggest that low intracellular energy production could slow the rapid amplification of ependymoglial cells,thereby inhibiting reactive gliosis,at early stages after spinal cord injury.Extracellular matrix degradation slows cellular responses,represses the expression of neurogenic genes,and reactivates a transcriptional program similar to that of embryonic neuroepithelial cells.These ependymoglial cells act as neural stem cells:they migrate and proliferate to repair the lesion and then differentiate to replace lost glial cells and neurons.This provides the regenerative microenvironment that allows axon growth after injury.

A specialized code for operation transient analysis and its application in fluoride salt-cooled high-temperature reactors

Fluoride salt-cooled high-temperature reactors(FHRs) include many attractive features, such as high temperature, large heat capacity, low pressure and strong inherent safety. Transient characteristics of FHR are particularly important for evaluating its operation performance. Thus, a specialized code OCFHR(operation and control analysis code of FHR) issued to study an experimental FHR's operation behaviors. The geometric modeling of OCFHR is based on one-dimensional lumped parameter method, and some simplifications are taken into consideration during simulation due to the existence of complex structures such as pebble bed, intermediate heat exchanger(IHX), air radiator(AR) and multiply channels.A point neutron kinetics model is developed, and neutron physics calculation is needed to provide some key inputs including axial power density distribution, reactivity coefficients and parameters about delayed neutron precursors. For analyzing the operational performance, five disturbed transients are simulated, involving reactivity step insertion, variations of coolant mass flow rate of primary loop and intermediate loop, adjustment of air inlet temperature and mass flow rate of air cooling system.Simulation results indicate that inherent self-stability of FHR restrains severe consequences under above transients,and some dynamic features are observed, such as large negative temperature feedbacks, remarkable thermal inertia and high response delay.

Analytical Modelling and Experiment of Novel Rotary Electro-Mechanical Converter with Negative Feedback Mechanism for 2D Valve

The manufacturing of spiral groove structure of two-dimensional valve(2D valve)feedback mechanism has shortcomings of both high cost and time-consuming.This paper presents a novel configuration of rotary electro-mechanical converter with negative feedback mechanism(REMC-NFM)in order to replace the feedback mechanism of spiral groove and thus reduce cost of valve manufacturing.In order to rapidly and quantitative evaluate the driving and feedback performance of the REMC-NFM,an analytical model taking leakage flux,edge effect and permeability nonlinearity into account is formulated based on the equivalent magnetic circuit approach.Then the model is properly simplified in order to obtain the optimal pitch angle.FEM simulation is used to study the influence of crucial parameters on the performance of REMC-NFM.A prototype of REMC-NFM is designed and machined,and an exclusive experimental platform is built.The torque-angle characteristics,torque-displacement characteristics,and magnetic flux density in the working air gap with different excitation currents are measured.The experimental results are in good agreement with the analytical and FEM simulated results,which verifies the correctness of the analytical model.For torque-angle characteristics,the overall torque increases with both current and rotation angle,which reaches about 0.48 N·m with 1.5 A and 1.5°.While for torque-displacement characteristics,the overall torque increases with current yet decrease with armature displacement due to the negative feedback mechanism,which is about 0.16 N·m with 1.5 A and 0.8 mm.Besides,experimental results of conventional torque motor are compared with counterparts of REMC-NFM in order to validate the simplified model.The research indicates that the REMC-NFM can be potentially used as the electro-mechanical converter for 2D valves in civil servo areas.

Zyxin promotes hepatocellular carcinoma progression via the activation of AKT/mTOR signaling pathway

Hepatocellular carcinoma(HCC)is a common malignancy that is driven by multiple genes and pathways.The aim of this study was to investigate the role and specific mechanism of the actin-interacting protein zyxin(ZYX)in HCC.We found that the expression of ZYX was significantly higher in HCC tissues compared to that in normal liver tissues.In addition,overexpression of ZYX in hepatoma cell lines(PLC/PRF/5,HCCLM3)enhanced their proliferation,migration and invasion,whereas ZYX knockdown had the opposite effects(SK HEP-1,Huh-7).Furthermore,the change in the expression levels of ZYX also altered that of proteins related to cell cycle,migration and invasion.Similar results were obtained with xenograft models.The AKT/mTOR signaling pathway is one of the key mediators of cancer development.While ZYX overexpression upregulated the levels of phosphorylated AKT/mTOR proteins,its knockdown had the opposite effect.In addition,the AKT inhibitor MK2206 neutralized the pro-oncogenic effects of ZYX on the HCC cells,whereas the AKT activator SC79 restored the proliferation,migration and invasion of HCC cells with ZYX knockdown.Taken together,ZYX promotes the malignant progression of HCC by activating AKT/mTOR signaling pathway,and is a potential therapeutic target in HCC.

Metastatic urothelial carcinoma harboring ERBB2/3 mutations dramatically respond to chemotherapy plus anti-PD-1 antibody:A case report

BACKGROUND Immune checkpoint inhibitors(ICIs)targeting the programmed death(PD)-1 pathway have substantially changed the clinical management of metastatic urothelial carcinoma(m UC);however,the response rate remains low.There are ongoing efforts to identify robust biomarkers that can effectively predict the treatment response to ICIs.Previous studies have suggested that ERBB2/3 mutations are associated with the efficacy of ICIs in gallbladder carcinoma.CASE SUMMARY We present a 59-year-old man with m UC harboring ERBB2/3 mutations(in-frame insertion of ERBB2 and ERBB3 amplification),negative PD-ligand 1 expression,and low tumor mutation burden.He received anti-PD-1 antibodies and paclitaxel as second-line treatment.After two cycles of treatment,the lung metastases had significantly shrunk,achieving good partial remission.After six cycles of combination therapy,the patient received sindilimab 200 mg once every 3 wk as maintenance monotherapy.At the last follow-up,the patient continued to exhibit a partial response and progression-free survival for as long as 19 mo.CONCLUSION ERBB2/3 mutations may represent a predictive biomarker for selecting a subgroup of m UC patients who will benefit from ICIs.

Theoretical and experimental investigation on novel 2D maglev servo proportional valve

This paper presents a novel two-dimensional maglev servo proportional cartridge valve(2 D maglev valve),where a contactless maglev coupling is introduced between electro-mechanical converter and valve body to realize functions of force transmission,spool position feedback and linear-rotary motion conversion.Such configuration can effectively reduce cost of both valve manufacturing and electro-mechanical converter,while still maintain features of 2 D valve such as null pilot leakage,high power-to-weight ratio and excellent anti-pollution capacity.Firstly,the characteristic equation of the valve is derived using linear theory,and the stability criterion is established for parameter determination.The influences of crucial structural parameters such as initial height of overlapping area,width of high-pressure and low-pressure holes,acting radius of magnetic force,pitch angle of maglev coupling,length of sensitive chamber and system pressure on the dynamic response are investigated based on AMESim numerical simulation.The prototype valve is then designed and manufactured and a special test rig is built.The no-load flow characteristic,load flow characteristic,leakage characteristic,amplitude and phase frequency characteristics and step response under different system pressures are measured.The experimental results are in a good agreement with the simulated analysis.As an over-damped system,the prototype valve has excellent working stability,which can reach a no-load flow rate of 105.9 L/min with hysteresis of 3.51%,amplitude bandwidth of 28.7 Hz and phase bandwidth of 42.8 Hz under 21 MPa.The research indicates that the 2 D maglev valve can be a potential solution of flow rate control valve for flight control surface system of civil aircraft with high pressure and large flow rate application.

二维活塞泵用滚子-凸轮轨道机构的建模和验证（英文）

目的:由于液压行业对高速重载的要求越来越高,传统轴向柱塞泵中存在的润滑与泄漏的矛盾也越发明显。针对传统轴向柱塞泵中因结构产生的倾斜力、低功率密度、恶劣的摩擦副工况、较大的流量脉动等限制,本文旨在提出一种具有内力平衡、功率密度高、无纯粹的滑动摩擦副且工况优秀、能消除结构性流量脉动等优点的二维活塞泵,并通过对其工作原理的详细分析,探讨其具有上述优点的理论依据。创新点:1.提出二维活塞泵;该泵利用二维运动转换机构中活塞部件的二维运动,同时实现了吸排油功能和配流功能,提高了集成化;通过其活塞旋转1周可以使泵吸排油4次的结构设计,提高了功率密度;轴向与轴向对称的独特结构布局,实现了内力平衡,消除了传统轴向柱塞泵中无法消除的倾覆力偶;相对于传统轴向柱塞泵,吸排油与配流功能的集成减少了摩擦副的数量,且消除了纯粹的滑动摩擦副,打破了PV值的限制,意味着二维活塞泵有着实现更大流量压力分布的潜力。2.提出二维活塞泵运动转换机构中的锥滚子-凸轮接触结构,优化二维活塞泵运动转换机构的受力条件;3.建立二维活塞泵运动转换机构中锥滚子-凸轮接触副的通用型数学模型,通过运动学分析建立精确的凸轮表面模型(即二维活塞泵的运动学模型),为二维锥滚轮活塞泵的结构设计和进一步的静、动力学的研究提供理论基础。4.消除结构性流量脉动。方法:1.通过对二维活塞泵结构与工作原理的理论分析,讨论其相对于传统轴向柱塞泵所具有的优点。2.通过跑合实验,验证锥滚子-凸轮接触结构具有的受力条件。3.通过运动学分析与空间几何关系变换推导,得到运动转换机构中具有普遍指导意义的接触副的通用数学模型。4.通过实验曲线与理论曲线的对比,验证接触副数学模型的正确性与二维活塞泵所具有的消除结构流量脉动的潜力。5.通过滤波处理与模拟仿真,验证二维活塞泵能否消除结构性流量脉动。结论:1.二维活塞泵具有功能集成化高、内力平衡、功率密度高、无纯粹的滑动摩擦副且能消除流量脉动的优点。2.运动转换机构中锥滚子-凸轮接触结构具有更好的受力条件。3.建立的接触副数学模型可以指导二维活塞泵中运动转换机构的加工,且对二维活塞泵进一步的运动学与动力学的研究具有指导意义。4.二维活塞泵能消除结构性流量脉动。

Two-dimensional piston pump: Principle, design,and testing for aviation fuel pumps

Aviation fuel pumps of the future are required to be highly efficient and lightweight.As such,this work presents the designs of various mechanisms and structures of advanced twodimensional piston pumps for aero-engines,and their universal kinematic design methods are detailed herein.The efficiency of various piston pump prototypes was experimentally tested at various speeds in an open circuit.The experimental results indicate that two-dimensional piston pumps have a volumetric efficiency>91%and a higher power–mass ratio than conventional fuel pumps under all the conditions studied.Furthermore,the structural and material problems encountered during testing can provide a blueprint for further improvement of the design and processing of two-dimensional piston fuel pumps.

Ultra-stable and color-tunable manganese ions doped lead-free cesium zinc halides nanocrystals in glasses for light-emitting applications

All inorganic CsPbX_(3)(X=Cl,Br,and I)perovskite nanocrystals have made unprecedented radical progresses for opto-electronic applications,but their instability and toxicity of lead impede their wide applications.Herein,we report the first precipitation of leadfree Mn:Cs_(2)ZnX_(4) nanocrystals in glasses.Efficient green and red photoluminescence are realized from these Mn:Cs_(2)ZnX_(4 )nanocrystals in glasses.By adjusting the size and halide component in these nanocrystals,coordination environment of Mn^(2+)ions can be tuned,leading to tunable photoluminescence with improved quantum efficiency.It is illustrated that in-situ precipitation of these Mn:Cs_(2)ZnX_(4) nanocrystals in glasses significantly improves their thermal-,chemical-,and photo-stabilities,making them promising for light-emitting diodes with stable chromaticity coordinates.

Theoretical and experimental investigation on the efficiency of a novel roller piston pump

This study presents a novel roller piston pump,in which a cam guide-roller type rolling support is adopted to replace the sliding pair support of the swash plate-slipper pair to achieve the oil suction and discharge of the piston cavity.In addition,the shaft distribution is used to replace the original valve plate distribution and the driving shaft is used as the distribution shaft to remove the valve plate structure,which greatly simplifies the design of the axial piston pump.Such a configuration largely reduces the number of sliding friction pairs of the pump,and avoids the influence of the sliding friction pair on it under high-speed and variable-speed conditions.Firstly,mathematical models of the mechanical and volumetric efficiencies of the roller pump are deduced respectively through force analysis and the compressibility equation.Based on the numerical simulation of MATLAB and AMESim,the effects of load pressure and rotational speed on mechanical and volumetric efficiencies are studied respectively,and it is verified that the roller pump has no structural flow pulsation.The prototype pump is then designed and built,along with a special test rig.The outlet pressure,outlet flow,and torque of the pump under different load pressures and rotational speeds are measured,and the mechanical and volumetric efficiencies of the prototype pump under various load pressures and rotational speeds are obtained.The experimental results are in good agreement with the simulated analysis.When the load pressure is 8 MPa and the speed is 5000 r/min,the mechanical and the volumetric efficiencies are 85.5% and 96.8%,respectively.When the speed is increased to 10000 r/min,the mechanical and the volumetric efficiencies are 66.7% and 95.6%,respectively.The experimental results show that the proposed roller piston pump has excellent efficiency under wide-speed and high-speed conditions and can be a potential solution as a fuel pump in aerospace fuel systems.