ARRHENIUS ANALYSIS OF SINGLE-HEATED AND STEP-DOWN HEATED V_(79) AND L CELLSIN VITRO

The response to single heat treatment and Step-down heat (SDH) treatment in vitro of V79 and L cells was studied. Colony-forming ability was assayed in medium after treatment in vitro. Time-response curves were established and subjected to Arrhenius analysis. The Arrhenius curves showed inflection points at 43℃ for V79 cells and at 42℃ for L cells. The activation energies were 145 kcal/mole and 400 kcal/mole above and below 43℃ (P<0.05), respectively, for V79 cells, while 160 kcal/mole and 300 kcal/mole above and below 42℃ (P<0.05), respectively, for L cells. Thermosensitivity of L cells are markedly higher than V79 cells. Both V79 and L cells were sensitized by SDH. The SDH effect was characterized by a reduction in shoulder (an addition effect to sublethal damage), an increase in slope (thermosensitization), and the delay and disappearance of thermotolerant 'tail' for V79 and L cells at 45℃ to 40℃ and 44℃ to 42℃ SDH treatment respectively. Particularly, 42℃ to 39℃ or 42℃ to 40℃ SDH for L cells resulted in thermosensitization effect up to a factor of 7.1 or 2.7, respectively. The effect was quantified by thermorsensitization ratio (TSR), defined as T0 single heated/T0SDH-heated. The relative ratio was much higher for V79 than for L cells. Heat killing with SDH characterized by Arrhenius analysis showed that Step-down heating reduced the activation energy for heat killing more than single heating. The decrease of activation energy for L cells was markedly greater than for V79. These data suggest that greater cellular sensitivity under step-down heating conditions may reflect a different mechanism for cell killing.

Proton pump inhibitor step-down therapy for GERD:A multi-center study in Japan

AIM:To investigate the predictors of success in stepdown of proton pump inhibitor and to assess the quality of life(QOL).METHODS:Patients who had heartburn twice a week or more were treated with 20 mg omeprazole(OPZ) once daily for 8 wk as an initial therapy(study 1).Patients whose heartburn decreased to once a week or less at the end of the initial therapy were enrolled in study 2 and treated with 10 mg OPZ as maintenance therapy for an additional 6 mo(study 2).QOL was in-vestigated using the gastrointestinal symptom rating scale(GSRS)before initial therapy,after both 4 and 8 wk of initial therapy,and at 1,2,3,and 6 mo after starting maintenance therapy.RESULTS:In study 1,108 patients were analyzed.Their characteristics were as follows;median age:63(range: 20-88)years,sex:46 women and 62 men.The success rate of the initial therapy was 76%.In the patients with successful initial therapy,abdominal pain,indigestion and reflux GSRS scores were improved.In study 2,83 patients were analyzed.Seventy of 83 patients completed the study 2 protocol.In the per-protocol analysis,80%of 70 patients were successful for stepdown.On multivariate analysis of baseline demographic data and clinical information,no previous treatment for gastroesophageal reflux disease(GERD)[odds ratio (OR)0.255,95%CI:0.06-0.98]and a lower indigestion score in GSRS at the beginning of step-down therapy(OR 0.214,95%CI:0.06-0.73)were found to be the predictors of successful step-down therapy.The improved GSRS scores by initial therapy were maintained through the step-down therapy.CONCLUSION:OPZ was effective for most GERD patients.However,those who have had previous treatment for GERD and experience dyspepsia before stepdown require particular monitoring for relapse.

文冠果油对雄性小鼠记忆能力的影响

为了对文冠果油相关产品的开发提供数据支撑,将健康雄性小鼠分为4个组,即对照组(玉米油)、文冠果油低剂量组〔2.1 g/(kg·d)〕、文冠果油中剂量组〔4.2 g/(kg·d)〕和文冠果油高剂量组〔12.5 g/(kg·d)〕,分别经口给予小鼠灌胃1个月后,测定小鼠体质量,并进行跳台试验、避暗试验、水迷宫试验以评价文冠果油对雄性小鼠记忆能力的影响,试验结束后测定小鼠海马和大脑皮质组织匀浆中多巴胺(DA)、5-羟色胺(5-HT)、去甲肾上腺素(NE)、乙酰胆碱(ACh)含量及乙酰胆碱酯酶(AChE)活性,探讨文冠果油对小鼠记忆能力的影响机制。结果表明:经过1个月的灌胃试验,各组小鼠体质量及其增长率均无显著差异;文冠果油组小鼠跳台试验、避暗试验、水迷宫试验均为阳性;文冠果油高剂量组小鼠海马和大脑皮质组织匀桨中5-HT、ACh、NE、DA含量明显升高,AChE活性明显降低。综上,文冠果油具有改善小鼠记忆的功能,且是通过改善单胺类神经递质和胆碱能神经递质的代谢发挥作用的。

基于降阶梯思维的一站式急救模式对高血压脑出血患者救治情况及肢体功能、神经功能的影响

目的研究降阶梯思维的一站式急救模式对高血压脑出血患者救治情况及肢体功能、神经功能的影响。方法选取2019年1月—2021年12月于四川省人民医院进行诊断并治疗的高血压脑出血患者120例作为研究对象,按照随机数字表法分为观察组和对照组,每组60例。对照组采取常规急救模式,观察组采取基于降阶梯思维的一站式急救模式。比较两组急救效率、功能恢复情况、脑血肿出血量、急救能力评分和护理满意度。结果观察组抢救成功率高于对照组,急诊停留时间、住院时间均短于对照组,差异有统计学意义(P<0.05)。治疗前,两组NIHSS评分、BI评分、脑血肿出血量比较,差异无统计学意义(P>0.05);治疗后,两组NIHSS评分低于治疗前,BI评分高于治疗前,脑血肿出血量少于治疗前,且观察组NIHSS评分低于对照组,BI评分高于对照组,脑血肿出血量少于对照组,差异有统计学意义(P<0.05)。观察组对护理人员专业知识、快速反应能力、医护配合评分均高于对照组,差异有统计学意义(P<0.05)。观察组护理总满意度高于对照组,差异有统计学意义(P<0.05)。结论基于降阶梯思维的一站式急救模式对高血压脑出血患者的急救成功率较高,患者的肢体功能、神经功能显著改善。

泄洪消力池消力墩消能特性数值模拟研究

消力墩是常用的泄洪消力池消能结构物之一,对其消能效果与结构优化研究在枢纽结构设计中具有重要作用。为此,基于描述非恒定流运动的雷诺平均(RANS)方程和描述紊流运动的Realizableκ-ε湍流模型,采用VOF自由表面追踪方法,建立了模拟大自由表面变形流体运动的数值计算模型,对坝面泄洪引起的跌坎型消力池内复杂流体运动及消力墩的消能特性进行研究。首先,对不同坝面泄洪条件下消力池内水流运动进行模拟,通过将自由液面、水流流态及底板压强分布等的模拟结果与室内实测数据进行对比,验证了模型的模拟精度和可靠性;在此基础上,模拟分析了矩形、直角梯形和T形三种典型消力墩对消力池内水流流速、液面形态及湍动能分布的影响,探讨了长、宽、高相同、几何形状不同的消力墩的消能效果。结果表明,对水流能量的耗散作用,矩形消力墩优于直角梯形消力墩、直角梯形消力墩优于T形消力墩。

Research of Step-down Stress Accelerated Degradation Data Assessment Method of a Certain Type of Missile Tank

The performance degradation rates of the missile tank are generally time-varying functions uneasily evaluated by general classical evaluation methods. This paper develops a segmented nonlinear accelerated degradation model （SNADM） based on the equivalent method of accumulative damage theory, which tackles the problem that product life is difficult to be determined with degradation rate being a function of the variable of time. A segmented expression of the function of population accumulative degradation is derived. And combined with nonlinear function, an accelerated degradation function, i.e., SNADM is obtained. The parameters of the SNADM are identified by numerical iteration, and the statistical function of degradation track is extrapolated. The reliability function is determined through the type of random process of the degradation distribution. Then an evaluation of product storage life is undertaken by combining the statistical function of degradation track, reliability function and threshold. An example of a missile tank undergoes a step-down stress accelerated degradation test （SDSADT）, in which the results with the SNADM and the classical method are evaluated and compared. The technology introduced is validated with the resultant coincidence of both evaluated and field storage lives.

Process performance and quality attributes of temperature and step-down relative humidity controlled hot air drying of Panax notoginseng roots

The effects of temperature and step-down relative humidity controlled hot-air drying(THC-HAD)on the drying kinetics,energy efficiency and quality,i.e.,rehydration ratio(RR),color parameters(L*,a*,b*),total color difference(ΔE*),Panax notoginseng saponins(PNS)content,and ginsenosides content(R1,Rg1,Re,Rd,Rb1)of Panax notoginseng roots were evaluated.The drying time was significantly affected by the drying temperature followed by the relative humidity(RH)of the drying air.Special combination of drying conditions,i.e.,drying temperature of 50°C,relative humidity of 40%for 3 h and then continuous dehumidification from 40%to 8%allowed to shorten the drying time by 25%compared to drying at the same temperature and continuous dehumidification.The longer was the drying time under constant high RH of drying air,the lower was the RR of dried samples.The step-down RH strategy contributed to the formation of a porous structure,enhancement of drying efficiency and quality improvement.Generally,the ginsenosides content increased with the increase in temperature,while no obvious trend was recorded for ginsenoside R1.The contents of the ginsenoside R1,Rg1,Rb1 and PNS decreased with the increase in the drying time under constant high RH.Taking into account the drying time,energy consumption and quality attributes,drying at the temperature of 50°C,constant RH of 40%for 3 h and then step-down RH from 40%to 8%was proposed as the most favorable combination of drying conditions for dehydration of whole Panax notoginseng roots.

Comparison Analysis of Efficiency Between Double-Synchronous Step-Down-Stress and Step-Up-Stress Accelerated Life Tests

Double-crossed-step-stress(DCSS) accelerated life test(ALT) method is widely used for estimating the lifetime of products with high reliability and long lifetime. In order to further reduce the test time and test cost, a double-synchronous-step-stress(DSSS) ALT method which combines a double-synchronous-step-downstress(DSSDS) ALT method and a double-synchronous-step-up-stress(DSSUS) ALT method is proposed. The accelerated stresses decrease and increase in a synchronous way with one step in the DSSDS-ALT and DSSUSALT methods, respectively. Monte Carlo method is adopted to simulate the two methods, and the validity and efficiency of them are demonstrated by the simulation results. In addition, a comparison analysis of efficiency between DSSDS-ALT method and DSSUS-ALT method is carried out. The result shows that the DSSDS-ALT method compared with the DSSUS-ALT method can significantly improve the test efficiency under the same test condition.

一种适用于多场景的新型无变压器高降压比变换器

针对传统Buck变换器受最小占空比限制的影响,无法适用于高降压比场合的问题,提出了一种新型无变压器高降压DC-DC变换器。首先,详细地分析了所提变换器的工作模态和开关时序。其次,在控制层面,该变换器应用交错式脉宽调制的开关模式,不但增加了其带载能力,还极大减少了元器件的电压应力。对新型高降压比变换器的工作过程进行分析,同时在理论上进行了参数设计。最后,搭建500/26 V 430 W的样机进行实验,实验结果充分证明了理论的正确性和可行性。

微生物产表面活性剂降压增注提高采收率实验研究

针对低渗油田注水井压力高、配注不达标、注水开发效果差等问题,在研究分析储层特征、油藏条件、地面配套的基础上,从原油样品中优选能产生高效生物表面活性剂的菌株Bhj-04。通过室内毛细管驱替实验、岩石润湿性测试、油水乳化现象对比、原油沾附效果评价、岩心驱替模拟实验分析该高效微生物产表面活性剂的性能。实验表明:此菌株产高效表面活性剂具有良好的润湿反转性,经菌剂液体浸泡的岩石样品表面润湿性转变为亲水性能,能有效降低油水界面张力防止水锁导致的储层伤害;岩心驱替实验中加入菌液后能有效提高岩心驱替过程采收率6%,注水井压力降落32.9%。效果明显,研究成果可对低渗油田降压增注提高采收率提供参考意义。

某大型工业建筑中压供电方案比选

大型工业建筑的建筑面积和用电量都很大,超出单路市政10 kV回路供电容量,此类项目考虑市政35 kV进线供电或多路10 kV回路供电。35 kV进线可采用二级降压或者一级降压给末端设备供电。从技术和经济两方面比较35 kV进线二级降压、35 kV进线一级降压供电方案和多路10 kV回路供电方案的优缺点,为大型工业建筑工程提出最优中压供电方案。

基于模态分析法的群组列车牵引供电系统并联谐振频率研究

重载铁路运载量的不断增长,可采用同一供电臂增加运行列车数量来解决运能不足问题。但当列车数量增多时,多列车发出的谐波电流会分布在牵引网多位置处,且会使谐波电流叠加,引发严重的牵引供电系统并联谐振事故,因此,有必要研究多列车运行情况下系统谐波谐振频率分布。利用牵引网多导体降阶方法,得到简化的牵引网等效电路模型。通过采用模态分析方法,研究多列车在不同功率运行情况下牵引供电系统并联谐振频率的变化,得到谐波谐振的节点参与信息。研究表明:当6辆列车在牵引网以4~8 MW功率运行时,引发系统谐振的低次谐波次数为38~43次,高次谐波次数为116~118次。

浅析eSeis采集站主电源设计

随着公司自主研发的eSeis节点仪器在国内多个项目的成功应用,后期的维护和改进工作也在如期进行。本文结合eSeis采集站主电源电路,简要介绍了LTC3622芯片的特性和工作原理,并针对在电路研究过程中发现的问题提出了自己的想法。

基于EG1163S的降压开关电源设计

随着技术的进步,开关电源朝着小型、轻量及高效的方向发展。以高压大电流降压型直流/直流(Direct Current/Direct Current,DC/DC)电源管理芯片EG1163S和金属氧化物半导体场效应晶体管(Metal Oxide Semiconductor Field Effect Transistor,MOSFET)为核心器件设计的降压型开关电源具有小型、低损耗及高效率的特点。该电源由滤波电路、DC/DC转换电路、限流保护电路以及金属氧化物半导体(Metal Oxide Semiconductor,MOS)管驱动电路等搭建而成,具有对高电压降压的功能,十分适用于高压大电流场合。

半钢子午线轮胎两段一次法成型机的研制

半钢轮胎成型中两次法和一次法两种工艺一直并行,近年来一次法设备发展迅速,导致两次法工艺逐步边缘化,甚至两次法擅长的AT、MT轻卡系列轮胎都没有对应的设备支撑。本文旨在提供一种高智能化、高效率的两段成型方法和成型设备。

不同降压模式在老年高血压合并冠心病患者PCI术后的应用效果研究

目的探讨强化降压与标准降压治疗老年高血压合并冠心病患者经皮冠状动脉介入术(PCI)术后的效果及安全性。方法86例老年高血压合并冠心病PCI患者以随机数字表法分为对照组和研究组,每组43例。对照组给予标准降压治疗[目标收缩压(SBP)<135 mmHg],研究组给予强化降压治疗(目标SBP<120 mmHg),自治疗起始随访12个月观察效果。记录2组患者治疗前后的24 h SBP和舒张压(DBP)变异系数;采用超声心动图评价治疗前后心功能改变;采用欧洲五维健康评价量表(EQ-5D-3L)中的视觉模拟量表评价健康状况,采用患者健康问卷抑郁量表(PHQ-9)评价抑郁情绪,采用焦虑自评量表(SAS)评价焦虑情绪,采用国际版跌倒效能量表(FES-I)评价跌倒风险。结果2组患者治疗前24 h SBP及24 h DBP变异系数、左心室射血分数(LVEF)、左心室质量指数(LVMI)、左心房容积指数(LAVI)、EQ-5D-3L得分、PHQ-9得分、SAS得分、FES-I得分差异均无统计学意义(P>0.05);研究组治疗后的24 h SBP、24 h DBP变异系数、LAVI、PHQ-9得分、SAS得分及FES-I得分均低于对照组,LVEF、LVMI、EQ-5D-3L得分高于对照组(P<0.05);研究组、对照组治疗期间总不良反应发生率比较差异无统计学意义(P>0.05);研究组心脑血管新发事件总发生率低于对照组(P<0.05)。结论强化降压治疗在降低老年高血压合并冠心病患者PCI术后的24 h血压变异系数、改善心功能方面优于标准降压治疗,可提高患者生活质量,且安全性良好。

肝癌肝移植术前降期中载药微球经动脉化疗栓塞应用效果观察

目的:探究载药微球经动脉化疗栓塞(DEB-TACE)与常规经动脉化疗栓塞术(cTACE)在肝癌肝移植术前降期治疗中的应用价值。方法:选取2015年1月至2022年1月我院74例因肝细胞性肝癌(HCC)行经典原位肝移植患者的临床资料,开展回顾性研究。其中36例肝移植术前行DEB-TACE降期治疗,作为DTACE组,38例肝移植术前行cTACE降期治疗,作为cTACE组。比较两组降期治疗疗效、血清肿瘤标志物[甲胎蛋白(AFP)、糖类抗原199(CA199)、E-钙黏蛋白(EC)]、肝功能指标[天门冬氨酸氨基转移酶(AST)、总胆红素(TBIL)、丙氨酸氨基转移酶(ALT)]、预后相关标志物[血管内皮生长因子(VEGF)、分泌型蛋白Dickkopf-1(DKK1)、CD24]、不良反应发生率、肝移植术后1年复发转移情况,采用酶联免疫吸附法检测血清VEGF、DKK1、CD24水平。结果:DTACE组降期治疗缓解率(83.33%)与cTACE组(71.05%)对比差异无统计学意义(P>0.05);DTACE组治疗后血清AFP、CA199、EC水平均低于cTACE组,差异具有统计学意义(P<0.05);DTACE组治疗后血清AST、TBIL、ALT水平均低于cTACE组,差异具有统计学意义(P<0.05);DTACE组治疗后血清VEGF、DKK1、CD24水平均低于cTACE组,差异具有统计学意义(P<0.05);DTACE组恶心/呕吐、腹痛、发热、肝脓肿发生率(11.11%、16.67%、69.44%、2.78%)与cTACE组(18.42%、21.05%、76.32%、7.89%)对比差异无统计学意义(P>0.05);DTACE组肝移植术后1年复发率、转移率(5.56%、10.53%)与cTACE组(11.11%、18.42%)对比差异无统计学意义(P>0.05)。结论:肝癌肝移植术前降期治疗中采用DEB-TACE与cTACE均能获得良好治疗效果,其中DEB-TACE能更明显下调血清肿瘤标志物及预后相关标志物水平,在保护肝功能方面具有明显优势。

分布式储能中大降压比Buck变换器的优化设计

研究一种具有大降压比、低开关电压应力的新型Buck变换器,主要用于适配分布式储能系统中可再生能源输出与电池组之间的大压差。该变换器由低侧开关型降压单元与开关电感型降压单元级联而成。在介绍其工作模式和稳态特性的基础上,着重分析了变换器中各器件的功率损耗和电气应力,根据分析结果进行器件的优化选择和电路的优化设计。利用SIMPLIS软件进行仿真分析的同时,测试了一台峰值效率为94.6%、功率为750 W的实验样机。测试结果表明,该变换器具有极强的降压能力和较低的元件电气应力,同时能维持较高的变换效率。

基于多分类集成的降压式变换器电路故障预测算法

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