An Adaptive Sequential Replacement Method for Variable Selection in Linear Regression Analysis

With the rapid development of DNA technologies, high throughput genomic data have become a powerful leverage to locate desirable genetic loci associated with traits of importance in various crop species. However, current genetic association mapping analyses are focused on identifying individual QTLs. This study aimed to identify a set of QTLs or genetic markers, which can capture genetic variability for marker-assisted selection. Selecting a set with k loci that can maximize genetic variation out of high throughput genomic data is a challenging issue. In this study, we proposed an adaptive sequential replacement (ASR) method, which is considered a variant of the sequential replacement (SR) method. Through Monte Carlo simulation and comparing with four other selection methods: exhaustive, SR method, forward, and backward methods we found that the ASR method sustains consistent and repeatable results comparable to the exhaustive method with much reduced computational intensity.

Calcium-containing versus calcium-free replacement solution in regional citrate anticoagulation for continuous renal replacement therapy:a randomized controlled trial

Background: A simplified protocol for regional citrate anticoagulation (RCA) using a commercial calcium-containing replacement solution, without continuous calcium infusion, is more efficient for use in continuous renal replacement therapy (CRRT). We aim to design a randomized clinical trial to compare the safety and efficacy between calcium-free and calcium-containing replacement solutions in CRRT with RCA.Methods: Of the 64 patients receiving RCA-based postdilution continuous venovenous hemodiafiltration (CVVHDF) enrolled from 2017 to 2019 in West China Hospital of Sichuan University, 35 patients were randomized to the calcium-containing group and 29 to the calcium-free replacement solution group. The primary endpoint was circuit lifespan and Kaplan-Meier survival analysis was performed. Secondary endpoints included hospital mortality, kidney function recovery rate, and complications. The amount of 4% trisodium citrate solution infusion was recorded. Serum and effluent total (tCa) and ionized (iCa) calcium concentrations were measured during CVVHDF.Results: A total of 149 circuits (82 in the calcium-containing group and 67 in the calcium-free group) and 7609 circuit hours (4335 hvs. 3274 h) were included. The mean circuit lifespan was 58.1 h (95% CI 53.8-62.4 h) in the calcium-containing groupvs. 55.3 h (95% CI 49.7-60.9 h, log rankP = 0.89) in the calcium-free group. The serum tCa and iCa concentrations were slightly lower in the calcium-containing group during CRRT, whereas the postfilter iCa concentration was lower in the calcium-free group. Moreover, the mean amounts of 4% trisodium citrate solution infusion were not significantly different between the groups (171.1 ± 15.9 mL/hvs. 169.0 ± 15.1 mL/h,P = 0.49). The mortality (14/35 [40%]vs. 13/29 [45%],P = 0.70) and kidney function recovery rates of AKI patients (19/26, 73%vs. 14/24, 58%,P = 0.27) were comparable between the calcium-containing and calcium-free group during hospitalization, respectively. Six (three in each group) patients showed signs of citrate accumulation in this study.Conclusions: When compared with calcium-free replacement solution, RCA-based CVVHDF with calcium-containing replacement solution had a similar circuit lifespan, hospital mortality and kidney outcome. Since the calcium-containing solution obviates the need for a separate venous catheter and a large dose of intravenous calcium solution preparation for continuous calcium supplementation, it is more convenient to be applied in RCA-CRRT practice.

Effect of L-carnitine on Cardiomyocyte Apoptosis and Cardiac Function in Patients Undergoing Heart Valve Replacement Operation

Summary： The effects of L-carnitine, as an ingredient of cardioplegia solution, on cardiac function and cardiomyocyte apoptosis in patients undergoing heart valve replacement operation were investigated. Twenty-three cases undergoing heart valve replacement with cardiopulmonary bypass （CPB） were randomly allocated into two groups： L-carnitine group （n=12, 12 g/L L-carnitine was put in the ST. Thomas cardioplegia） and control group （n=11, identical to the L-carnitine group except that normal saline was administered instead of L-carnitine）. Serum cardial troponin I （cTnI） levels, the left ventricular ejection fraction （LVEF）, and cardiac index （CI） were measured perioperatively. A bit of myocardial tissue obtained from right atria was taken before CPB and by the end of intracardiac procedure to undergo electron microscopy examination and estimate apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling （TUNEL）. From the end of CPB to 3 days after operation, the serum levels of cTnI in the L-carnitine group was significantly lower than that in the control group （P〈0.05）. Heart color ultrasonogram showed that the CI index and LVEF at 7th day postoperatively in the L-carnitine group were significantly higher than in the control group （P〈0.05）. Compared to the control group, L-carnitine significantly alleviated the morphologic changes of cardiac muscle cells （electron microscopy examination） and decreased the amounts of apoptotic cardiac muscle cells （TUNEL）. Furthermore, the dosage of vasoactive drugs used after operation was significantly less in the L-carnitine group （P〈0.01）. It was concluded that L-carnitine cardioplegia solution could improve cardiac function in patients undergoing heart valve replacement operation and alleviate CPB-mediated apoptosis of cardiac muscle cells.

Optimal indicator for changing the filter during the continuous renal replacement therapy in intensive care unit patients with acute kidney injury:A crossover randomized trial

BACKGROUND:The study aims to investigate an optimal indicator for changing the filter during the continuous renal replacement therapy(CRRT)in intensive care unit(ICU)patients with acute kidney injury(AKI).METHODS:Patients with AKI requiring CRRT in an ICU were randomly divided into two groups for crossover trial,i.e.,groups A and B.Patients in the group A were firstly treated with continuous veno-venous hemofiltration(CVVH),followed by continuous veno-venous hemodiafiltration(CVVHDF).Patients in the group B were firstly treated with CVVHDF followed by CVVH.Delivered doses of solutes with different molecular weights at the indicated time points between groups were compared.A correlation analysis between the delivered dose and pre-filter pressure(P_(PRE))and transmembrane pressure(P_(TM))was performed.Receiver operating characteristic(ROC)curves were constructed to evaluate the accuracy of P_(TM) as an indicator for filter replacement.RESULTS:A total of 50 cases were analyzed,27 in the group A and 23 in the group B.Delivered doses of different molecular-weight solutes significantly decreased before changing the filter in both modalities,compared with those at the initiation of treatment(all P<0.05).In the late stage of CRRT,the possible rebound of serum medium-molecular-weight solute concentration was observed.P_(TM) was negatively correlated with the delivered dose of medium-molecular-weight solute in both modalities.The threshold for predicting the rebound of serum concentration of medium-molecularweight solute by P_(TM) was 146.5 mm Hg(1 mm Hg=0.133 k Pa).CONCLUSIONS:The filter can be used as long as possible within the manufacturer’s safe use time limits to remove small-molecular-weight solutes.P_(TM) of 146.5 mm Hg may be an optimal indicator for changing the filter in CRRT therapies to remove medium-molecular-weight solutes.

EXACT SOLUTION FOR FINITE DEFORMATION PROBLEMS OF CANTILEVER BEAM WITH VARIABLE SECTION UNDER THE ACTION OF ARBITRARY TRANSVERSE LOADS

This paper deals with finite deformation problems of cantilever beam with variable sec- tion under the action of arbitrary transverse loads.By the use of a method of variable replacement, the nonlinear differential equation with varied coefficient for the problem can be transformed into an equation with variable separable.The exact solution can be obtained by the integration method. Some examples are given in the paper,and the results of these examples show that this exact solution includes the existing solutions in references as special cases.

油田光热利用技术路线及解决方案研讨

在全球气候危机及全国“双碳”目标下,油气田企业加快绿色转型发展,推进低碳化油气生产。化石燃料占油气田生产过程能耗70%以上,光热利用是油气田清洁热力替代的主要方向。通过对工业光热应用领域各种主动式太阳能集热技术特点进行对比,分析油田多种用热环境的温位需求,认为光热技术多样性与油田用热需求多样性具有较高的匹配度。围绕油田多种用热环境,分析了单井拉油热电联供、小规模光热高效替代、大规模光热系统互联共享、复杂用热环境下光热梯级利用等多元化技术路线。针对光热项目在油田落地难度大的问题,从项目筛选、规模确定、系统设计、协同优化、能源管控等方面给出实施路径。油田光热利用方案制定中,因地制宜制定逐步清洁替代顺序是提高替代效益的关键,上下游系统思维及运行策略优化是设计方案优化的前提,严谨的可比性及全生命周期评估是多方案优选的基础,开展各种用热环境的研究实践是提高方案质量的重要路径。建议油田企业在实践中逐步深化认识,持续优化光热利用方案,规模化推动方案落地,进一步推动油气与新能源融合发展。

改良Del Nido与国产HTK停搏液在成人心脏瓣膜置换术中的应用效果

目的:分析改良Del Nido与国产HTK停搏液在成人心脏瓣膜置换术中的应用效果。方法:回顾性分析2022年1月—2023年7月钦州市第一人民医院收治的60例心脏瓣膜置换术患者资料。根据停搏液使用情况将其分为DN组(30例)和HTK组(30例)。HTK组使用国产HTK停搏液,DN组使用改良Del Nido停搏液。比较两组围手术期指标,术后24 h、48 h相关指标及肾功能。结果:DN组灌注次数多于HTK组,术后机械通气时间长于HTK组,主动脉阻断时间短于HTK组,自动复跳率高于HTK组,差异有统计意义(P<0.05)。两组术后24 h、48 h心肌肌钙蛋白(cTnI)、肌酸激酶同工酶(CK-MB)水平比较,差异无统计意义(P>0.05)。两组术后24 h、48 h血尿素氮(BUN)、血肌酐(Scr)水平比较,差异无统计意义(P>0.05)。结论:与国产HTK停搏液对比,改良Del Nido停搏液应用于成人心脏瓣膜置换术中能缩短主动脉阻断时间,提高自动复跳率,灌注次数较多,术后机械通气时间较长,但两者均具有良好的心肌保护作用。

两种心脏停搏液在体外循环下单纯心脏瓣膜置换术中的心肌保护效果

目的:比较两种心脏停搏液在体外循环下单纯心脏瓣膜置换术中的心肌保护效果。方法:将2019年5月至2022年7月四川省人民医院收治的108例单纯心脏瓣膜置换术患者分为两组,A组53例,使用组氨酸-色氨酸-酮戊二酸(HTK)液;B组55例,使用含血St.Thomas液。比较两组体外循环术中情况如体外循环时间、主动脉阻断时间、灌注次数、心脏复跳时间、心脏自动复跳率,主动脉阻断前以及术后2、12、24、48、72 h时血清肌钙蛋白Ⅰ(cTnⅠ)、肌酸激酶同工酶(CK-MB)、脑钠肽(BNP)、心型脂肪酸结合蛋白(HFABP)、丙二醛(MDA)、超氧化物歧化酶(SOD)水平,转流过程中血K^(+)、Na^(+)浓度,手术前后心排量与心指数,术后24 h多巴胺的用量及并发症等。结果:A、B组体外循环时间、主动脉阻断时间差异无统计学意义(P>0.05),A组灌注次数少于B组,心脏复跳时间短于B组,心脏自动复跳率高于B组(P<0.05);A组术后2、12、24、48 h时血清cTnⅠ、CK-MB、BNP、HFABP、MDA水平低于B组,SOD水平高于B组(P<0.05);A组转流中、转流后即刻血K^(+)、Na^(+)水平低于B组(P<0.05);A组术后12、24 h心排量与心指数高于B组(P<0.05);A组术后24 h多巴胺用量少于B组(P<0.05)。两组术后并发症发生率差异无统计学意义(13.2%vs 21.8%,P=0.240)。结论:相较于含血St.Thomas液,HTK液应用于体外循环下单纯心脏瓣膜置换术,心肌保护效果更佳。

2-己基癸酸改性的全溶液制备的CsPbBr_(3)量子点发光二极管

钙钛矿量子点发光二极管是极具发展潜力的新型显示技术。全无机CsPbX3(X=Cl,Br,I)钙钛矿量子点具有优异的光电性能,然而合成CsPbX3量子点时往往需要油酸(OA)和油胺(OAm)等配体的参与,这些配体和量子点之间的动态结合方式使其极易从量子点表面脱落,进而引发量子点的不稳定性现象。此外,油酸油胺的绝缘特性会阻碍发光二极管中载流子的传输并恶化器件性能。鉴于此,本文以CsPbBr_(3)量子点为研究对象,采用短链配体2-己基癸酸(DA)部分取代长链OA配体,系统探究了不同DA/OA摩尔比对CsPbBr_(3)量子点光学性能的影响。结果表明,经DA修饰的CsPbBr_(3)量子点表现出高达88.64%的光致发光量子产率。随后,将优化后的CsPbBr_(3)量子点应用到全溶液制备的发光二极管中,器件的最高亮度和最大外量子效率分别从9 cd·m^(-2)和0.04%提升至155 cd·m^(-2)和0.14%。接着,通过优化钙钛矿发光层和空穴传输层之间的能级匹配,进一步将器件的亮度和外量子效率提升至436 cd·m^(-2)和0.20%。

含胰岛素的心肌保护液在体外循环下心脏瓣膜置换术患者中的应用效果

目的 探讨含胰岛素的心肌保护液在体外循环下心脏瓣膜置换术患者中的应用效果。方法 93例接受体外循环下心脏瓣膜置换术治疗的患者根据使用心肌保护液的不同分为两组,对照组使用不含胰岛素的改良托马斯停跳液,研究组使用含胰岛素的改良托马斯停跳液,比较两组的体外循环停机后多巴胺用量、心肌指标以及并发症。结果 研究组体外循环停机后的多巴胺用量低于对照组,体外循环结束时、体外循环停机后24 h的cTnⅠ、 CK-MB水平均低于对照组,体外循环停机后48 h的CKMB水平低于对照组(P <0.05)。研究组的并发症总发生率为13.04%,低于对照组的29.79%(P <0.05)。结论 含胰岛素的心肌保护液用于体外循环下心脏瓣膜置换术患者可发挥较好的心肌保护作用,能有效减少血管活性药物用量,减少并发症的发生。

CVVH和CVVHDF对脓毒症并发急性肾损伤患者不同溶质清除能力的影响

目的探讨持续性静脉-静脉血液滤过(CVVH)和持续性静脉-静脉血液透析滤过(CVVHDF)对脓毒症并发急性肾损伤(AKI)患者不同溶质清除能力的影响。方法回顾性分析2021年4月至2022年4月该院重症监护室收治的69例进行持续性肾脏替代治疗(CRRT)的脓毒症并发AKI患者的临床资料。根据不同滤过方式分为CVVH组(35例)和CVVHDF组(34例)。统计所有患者的预后情况,比较两组患者的临床资料、治疗前后的实验室指标及不同溶质的清除率。结果治疗30 d后,CVVH组7例患者死于脓毒症引起的多器官功能衰竭,2例患者死于心力衰竭,4例患者需继续进行CRRT,3例患者肾功能部分恢复。CVVHDF组6例患者死于脓毒症引起的多器官功能衰竭,3例患者死于心力衰竭,3例患者需继续进行CRRT,4例患者肾功能部分恢复。其余患者肾功能完全恢复并转回普通病房。CVVH组超滤速度、输注泵流速均快于CVVHDF组,差异均有统计学意义(P<0.05)。两组治疗前后预估肾小球滤过率、白细胞计数、C反应蛋白、肌酐、血尿素氮水平比较,差异均无统计学意义(P>0.05)。CVVH组肌酐清除率低于CVVHDF组,白细胞介素(IL)-8、IL-6清除率均高于CVVHDF组,差异均有统计学意义(P<0.05)。结论CVVHDF对肌酐的清除能力强于CVVH,而对IL-8、IL-6的清除能力弱于CVVH。

脂血对血常规红细胞参数测定结果的干扰及处理方法

目的:探讨脂血对血常规红细胞参数测定结果的干扰及处理方法。方法:选取2021年9月—2023年8月在广西壮族自治区脑科医院行血常规检测且血脂异常增高的脂血标本128份,分析采用等量0.9%氯化钠溶液置换血浆处理前后血常规参数变化。结果:处理后,血红蛋白(HGB)、平均血红蛋白量(MCH)、平均血红蛋白浓度(MCHC)、血小板(PLT)水平低于处理前,差异有统计学意义(P<0.05);处理前后,白细胞(WBC)、红细胞(RBC)、红细胞压积(HCT)、红细胞平均体积(MCV)比较,差异无统计学意义(P>0.05);在128份脂血标本中,23份MCHC≥380g/L,占17.97%,105份MCHC<380g/L,占82.03%。处理后,350g/L≤MCHC<380g/L和MCHC≥380g/L组的HGB水平均低于处理前,差异有统计学意义(P<0.05);处理前后,MCHC<350g/L组的HGB水平比较,差异无统计学意义(P>0.05)。结论:当MCHC≥350g/L时,建议检查标本性状,若是脂血影响,可通过等量0.9%氯化钠溶液置换血浆法进行纠正,0.9%氯化钠溶液置换血浆法能有效降低脂血对血常规红细胞参数测定结果的干扰,为临床和患者提供准确的检验报告。

氯化液的海绵铜回收试验研究

本文采用石灰乳沉淀-铁粉置换法从氯化液中回收海绵铜,获得较好的效果。试验结果表明,Ca(OH)2乳液浓度为20%,沉淀反应pH=0,沉淀时间为3 h,置换时间为3 h,终点pH=0.42时,小型试验获得的产品海绵铜纯度为91.8%,二次滤液Cu浓度为4.13 mg/L;中间试验获得的产品海绵铜纯度为88.2%,二次滤液Cu浓度为15.1 mg/L。结果显示,产品海绵铜纯度均超过88%,Cu基本全部被置换,中间试验指标略低于小型试验指标。该工艺切实可行,达到预期。

高速铁路隧道盐溶角砾岩地质支护加固施工技术

西渝高铁合川东隧道长距离通过盐溶角砾岩,泥质胶结,遇水易软化,块石夹土,孤石含量大,围岩稳定性差,开挖支护安全风险高、施工工效低,隧底受施工扰动及地下水影响大,存在运营期结构安全风险。采取有效的开挖支护和基底处理措施对隧道施工安全和工期至关重要。文章从多种支护方式、隧底换填注浆、系统锚杆支护等方面试验对比分析,形成了一套成熟的铁路隧道盐溶角砾岩地质支护加固施工体系,为类似不良地质施工提供借鉴参考。

某悬索桥吊索更换方案及桥面标高调整技术研究

某桥为主缆跨径布置(33+75+33) m的钢桁梁悬索桥,针对主缆、桥塔、锚碇、索夹U形拉杆等病害,研究确定需更换主缆,对桥塔和锚碇进行加固,旧吊索更换至新主缆上,索夹U形拉杆更换为直拉杆。为选择合理的吊索更换方案,提出3种方案:方案一为从桥塔向跨中更换,方案二为从跨中向桥塔更换,方案三为从跨中和桥塔分别向1/4跨更换。与方案一和方案二相比,方案三吊索索力和旧主缆缆力变化更缓和,加劲梁线形可控,故确定采用方案三进行施工。在此基础上,提出矩阵分析和多目标向单一目标转化求解的方法,确定吊索长度调整量,进行索力和实际桥面标高调整,按照计算的吊索长度调整量进行调整后,吊索整体受力及桥面标高达到了设计要求的目标状态。

硒吸收后液的高效复用研究

针对以铜阳极泥为原料,经过回转窑硫酸化焙烧得到的硒吸收后液如何高效复用进行了分析,同时就硒吸收后液酸度对铜阳极泥处理时的脱铜效果和硒还原率进行了研究。通过调整更换吸收液周期,提高硒吸收后液酸度,降低了硒吸收后液产出量,实现了硒吸收后液完全复用到铜阳极泥处理脱铜工序,减少了硫酸等化工试剂用量,节约了生产成本。

CRRT结束后非隧道式导管封管前冲洗液使用情况现状调查

目的横断面调查连续性肾脏替代治疗(continuous renal replacement therapy,CRRT)后非隧道式导管封管前冲洗液使用现状,为导管功能维护与护理提供参考。方法采用问卷星对广东省78家医院进行调查,了解CRRT后非隧道式导管封管前冲洗液使用类型、剂量和使用注射器类型等。结果共收集问卷91份,有效问卷78份(排除来自同一医院的问卷13份),有效率85.7%。参与调查的CRRT护士的平均年龄为(33.78±5.97)岁,其中男性占19.2%,主管护师及以上职称占56.4%。生理盐水是CRRT后冲管的常见药物(97.5%),2家医院使用灭菌注射用水为冲管液。不同医院生理盐水冲管液剂量:5 ml[12(14.5%)]、10 ml[47(56.6%)]、15 ml[5(6.0%)]和20 ml[19(22.9%)];冲管使用的注射器容量类型有5 ml[1(1.2%)]、10 ml[29(35.4%)]、20 ml[45(54.9%)]和30 ml[7(8.5%)]。结论生理盐水是CRRT后非隧道式导管封管前冲洗液的主要类型,生理盐水冲洗剂量与使用注射器类型有多种形式。

铜渣辅助铁粉去除含铜砷酸性溶液中铜、砷的试验

湿法炼锌过程中,常采用铁粉置换法去除含铜砷酸性溶液中的铜、砷,但该方法要求溶液中n_(Cu):n_(As)≥3:1才能保证As的彻底沉降。正常生产的含铜砷酸性溶液中n_(Cu):n_(As)≤3:1,As沉降不彻底,容易产生砷化氢有毒有害气体。某冶炼企业在锌冶炼过程中产出含铜55%~60%的副产品铜渣,提出在铁粉置换工序中加入铜渣,并进行了试验验证。结果表明,在原料为该企业含铜砷酸性溶液前提下,当铁粉过量系数1.5倍时,不加入铜渣,铜砷去除率仅57.14%、26.73%;加入2 g/L铜渣,则铜砷去除率可达92.35%、89.85%;在较佳工艺参数反应时间1 h、温度80℃左右、铜渣添加量2 g/L、铁粉过量系数1.5倍条件下,除铜、砷率均可达到90%以上。该方法可减少铁粉消耗量、降低生产成本,为锌冶炼企业处理含铜砷酸性溶液提供了参考。

可换镶件多功能注射模优化解决方案

可换镶件多功能注射模是技工培训部为装配工程师及德国双元制学徒设计而开发,供模具设计与制造全流程工序学习,能够为工程师和学员提供系统全程参与加工和试模,从最终塑件的质量和生产效率进行分析,找出问题,并进行有效地解决。由于在试模过程中使用不同的材料,使得塑件会表现不同的问题点。介绍了注射成型出现的常见问题,提供了解决方案,为从事模具设计和装配工作的人员选择更合理更经济方案的提供借鉴。

FeCl_3蚀刻废液的除镍研究

以铁粉为置换剂 ,去除含镍 Fe Cl3 蚀刻废液中的镍组分 ,达到 Fe Cl3 蚀刻液再生利用的要求。研究了铁粉种类、铁镍比、反应温度、反应时间、溶液酸度等因素对 Fe Cl3 蚀刻废液中镍置换率的影响。结果表明 ,具有高表面活性的铁粉 ,在提高反应温度 ,Fe/Ni=1～ 3( m/m) ,反应时间约为 1 h,p H≈ 4的条件下 ,镍的置换率达