Effects of high-volume hemofiltration on alveolar- arterial oxygen exchange in patients with refractory septic shock

BACKGROUND：High-volume hemofiltration （HVHF） is technically possible in severe acute pancreatitis （SAP） patients complicated with multiple organ dysfunction syndrome （MODS）. Continuous HVHF is expected to become a beneficial adjunct therapy for SAP complicated with MODS. In this study, we aimed to explore the effects of fluid resuscitation and HVHF on alveolar- arterial oxygen exchange, the Acute Physiology and Chronic Health Evaluation II （APACHE II） score in patients with refractory septic shock. METHODS：A total of 89 refractory septic shock patients, who were admitted to ICU, the Provincial Hospital affiliated to Shandong University from August 2006 to December 2009, were enrolled in this retrospective study. The patients were randomly divided into two groups： fluid resuscitation （group A, n=41）, and fluid resuscitation plus high-volume hemofiltration （group B, n=48）, The levels of O2 content of central venous blood （CcvO2）, arterial oxygen content （CaO2）, alveolar-arterial oxygen pressure difference P（A-a）DO2, ratio of arterial oxygen pressure/alveolar oxygen pressure （PaO2/ PAO2）, respiratory index （RI） and oxygenation index （OI） were determined. The oxygen exchange levels of the two groups were examined based on the arterial blood gas analysis at different times （0, 24, 72 hours and 7 days of treatment） in the two groups. The APACHE II score was calculated before and after 7-day treatment in the two groups. The levels of CcvO2, CaO2 on day 7 in group A were significantly lower than those in group B （CcvO2：0.60±0.24 vs, 0.72±0.28, P〈0.05; CaO2：0.84±0.43 vs. 0.94±0.46, P〈0.05）. The level of oxygen extraction rate （O2ER） in group A on the 7th day was significantly higher than that in group B （ 28.7±2.4 vs. 21.7±3.4, P〈0.01）. The levels of P（A-a）DO2 and RI in group B on the 7th day were significantly lower than those in group A. The levels of PaO2/PAO2 and OI in group B on 7th day were significantly higher than those in group A （P〈0.05 or P〈0.01）. The APACHE II score in the two groups reduced gradually after 7-day treatment, and the APACHE II score on the 7th day in group B was significantly lower than that in group A （8.2±3.8 vs. 17.2±6.8, P〈0.01）. HVHF combined with fluid resuscitation can improve alveolar- arterial-oxygen exchange, decrease the APACHE II score in patients with refractory septic shock, and thus it increases the survival rate of patients.

CORRELATIONS BETWEEN OXY-HEMOGLOBIN AND RESPIRATORY EXCHANGE RATIO IN THE QUADRICEPS DURING THE EARLY PHASE OF EXERCISES

The early stage of exercises is crucial in sports training;however,its physiological mechanism is still unclear.The hemodynamic response was reported to be associated with respiratory exchange.Here,we aimed to explore the relationship between oxy-hemoglobin concentration change(HbO_(2))and respiratory exchange ratio(RER)during the early phase of exercises.Sixteen athletes of middle-distance race were selected from Wuhan Institute of Physical Education to conduct intermittent exercises on MERCURY4.0 at 80%VO_(2)peak intensity.Multiple physiological parameters were acquired by use of a near-infrared spectroscopy muscle oxygen monitor,a Cardiopulmonary Function MAX-II and a P-Lar,including HbO_(2),RER and others.A significant correlation was found between RER and HbO_(2)in quadriceps muscle in the thigh during the early phase of exercises.Thus,NIRS is capable of supervising sports training in terms of HbO_(2),which actually acted as an interpreter of RER change.

Development of high-aspect-ratio microchannel heat exchanger based on multi-tool milling process

A high-aspect-ratio microchannel heat exchanger based on multi-tool milling process was developed. Several slotting cutters were stacked together for simultaneously machining several high-aspect-ratio microchannels with manifold structures. On the basis of multi-tool milling process, the structural design of the manifold side height, microchannel length, width, number, and interval were analyzed. The heat transfer performances of high-aspect-ratio microchannel heat exchangers with two different manifolds were investigated by experiments, and the influencing factors were analyzed. The results indicate that the magnitude of heat transfer area per unit volume dominates the heat transfer performances of plate-type micro heat exchanger, while the velocity distribution between microchannels has little effects on the heat transfer performances.

Effects of Heat Exchange Tube Structural Parameters on Performance of Vehicle Radiator

In order to improve the performance of vehicle radiators, a two-dimensional heat transfer steady-state model of the radiator was set up. The influence of the structural parameters (axial ratio) of the heat exchange tube on the windward side on the heat transfer performance of the radiator was studied. With the increase of the axial ratio of the heat exchange tube on the windward side, the heat exchange capacity of the heat exchange tube surface slightly decreases. The heat exchange area increases significantly, which increases the total heat exchange of the radiator and improves the heat transfer performance of the radiator. When the axial ratio increases from 1.0 to 2.0, the average surface heat transfer capacity decreases from 5664.16 W/m2 to 5623.57 W/m2.

Delisting in Athens Stock Exchange

The scope of this paper is to contribute to the question of delisting (both voluntary and involuntary), with particular emphasis on the initial conditions leading up to the Initial Public Offering (IPO) of the firms. The case of Athens Stock Exchange (ASE) is examined, specifically the IPOs of years 1996-2004 and their subsequent performance (delisting or not) till the end of 2017. We find that the probability of delisting is positively associated with the size of the issuance and the degree of earnings’ manipulation and negatively associated with audit quality, information transparency, and market timing. The effects of audit quality, size of issuance, and earnings’ manipulation are accentuated in instances of voluntary delisting while the effect of market timing is more clearly pronounced in instances of involuntary delisting. Our results are robust to a number of confounding factors including size, profitability, leverage, liquidity, growth options, and corporate governance. Our work is not replication of existing studies;in addition, we choose ASE as in that capital market there were many delistings the last two decades.

Fluid flow and heat transfer characteristics of spiral coiled tube: Effects of Reynolds number and curvature ratio

Numerical analysis was performed to investigate flow and heat transfer characteristics in spiral coiled tube heat exchanger. Radius of curvature of the spiral coiled tube was gradually increased as total rotating angle reached 12n. As the varying radius of curvature became a dominant flow parameter, three-dimensional flow analysis was performed to this flow together with different Reynolds numbers while constant wall heat flux condition was set in thermal field. From the analysis, centrifugal force due to curvature effect is found to have significant role in behavior of pressure drop and heat transfer. The centrifugal force enhances pressure drop and heat transfer to have generally higher values in the spiral coiled tube than those in the straight tube. Even then, friction factor and Nusselt number are found to follow the proportionality with square root of the Dean number. Individual effect of flow parameters of Reynolds number and curvature ratio was investigated and effect of Reynolds number is found to be stronger than that of curvature effect.

The Golden Ratio Theorem: A Framework for Interchangeability and Self-Similarity in Complex Systems

The Golden Ratio Theorem, deeply rooted in fractal mathematics, presents a pioneering perspective on deciphering complex systems. It draws a profound connection between the principles of interchangeability, self-similarity, and the mathematical elegance of the Golden Ratio. This research unravels a unique methodological paradigm, emphasizing the omnipresence of the Golden Ratio in shaping system dynamics. The novelty of this study stems from its detailed exposition of self-similarity and interchangeability, transforming them from mere abstract notions into actionable, concrete insights. By highlighting the fractal nature of the Golden Ratio, the implications of these revelations become far-reaching, heralding new avenues for both theoretical advancements and pragmatic applications across a spectrum of scientific disciplines.

An Influencing Factor - Water-Filter Ratio on Heat Resistance of Condensate Polishing Filter Material in Water

In air-cooled condenser, high temperature condensing water m summer which approaching and exceed 60＊ C, which may result in filter materials degradation and release impurities. This paper discusses an influencing factor, water-filter ratio （soaking solution and filter quality ratio）, on leachable dissolution rate and filter material degradation rate m high temperature water. The UV absorption at 254nm （A254） and the exchange capacity ware measured after heat test as composite indicators. In addition, the Wends of A254 variation with heating time were measured in different water-filter ratio. The stability is probably due to the effect of water-filter ratio. This has been further borne out that, water-filter ratio increases, leachable concentration decreases exponentially and tends to a fLxed value.

水平挡板流场对燃料电池性能与传质的影响

在质子交换膜燃料电池(PEMFC)流道内设置微结构,可增强反应气体从流道到催化层的传质能力,并提高电池性能。建立并对比交错安装挡板与对置安装挡板的模型,得出交错安装的布置方式,更有利于电池性能的提升。建立4种不同堵塞率的模型,发现随着堵塞率的升高,电池的最大净功率密度和极限电流密度增大,95%堵塞率模型的净功率密度最高,为1.053 W/cm^(2),较无挡板模型提升了14.58%,直至电流密度2.8 A/cm^(2)时,仍未出现明显的浓差极化。调整挡板夹角,综合考虑传质能力和泵送损失情况下,夹角为15°时,电池净功率密度最高。

成品油“期货稳价订单”模式的套期保值效率研究——以柴油和汽油为例

“期货稳价订单”模式对于稳定能源化工产业链的大宗商品价格、保障能源化工供应链安全具有重要意义。研究“期货稳价订单”模式下的上海原油期货和柴油、汽油产品的跨品种套期保值效率,以2018年9月到2022年7月上海原油期货价格和柴油、汽油现货价格为样本,使用OLS、B-VAR、ECM、BEKK-GARCH模型计算套期保值效率,得到最优套期保值比率。研究发现,风险管理子公司可以通过参与“期货稳价订单”降低风险;柴油、汽油日数据中基于BEKK-GARCH模型计算得出的动态套期保值比率效果最优,周度、月度数据中基于OLS模型的效果最优;套期保值效率随着样本期限的拉长会逐渐提高,套期保值期限管理是降低成品油价格波动风险的重要渠道;通过汽油和柴油的对比研究,增强了回归结果的可信度,为该模式未来扩充油气业务品种提供了参考依据。

长期施用有机肥对松嫩平原盐碱土壤盐碱性质和化学计量比的影响

盐碱土盐碱化程度高、养分有效性低,施加有机肥可以促进土壤盐分淋洗,降低土壤盐碱化程度,增加养分含量和土壤碳、氮、磷的供应能力。根据土壤施加腐熟牛粪的年限,设置施加腐熟牛粪21(Y21)、18(Y18)、15年(Y15)和未施加腐熟牛粪(CK)共4个处理,采集各处理0—20和20—40 cm土层的土壤样品,分析土壤盐碱性质和养分含量。结果表明,0—20和20—40 cm土层Y21、Y18、Y15处理有机碳(soil organic carbon,SOC)、全氮(total-N,TN)和全磷(total-P,TP)含量显著高于CK;土壤水溶性盐离子、pH、电导率(electrical conductance,EC)、钠吸附比(sodium adsorption ratio,SAR)和碱化度(exchangeable sodium percentage,ESP)较CK显著降低。在0—20和20—40 cm土层,Y21、Y18、Y15处理碳氮比(C/N)较CK显著降低;与CK相比,Y21与Y15处理0—20 cm土层氮磷比(N/P)由0.95显著增加至1.84和2.11,20—40 cm土层N/P由1.15显著增加至2.25和2.44;土壤碳磷比(C/P)在0—20 cm土层规律不明显,在20—40 cm土层Y21、Y18、Y15处理与CK相比差异不显著。多元线性回归模型显示,C/N受SOC、TN和ESP影响,N/P和C/P主要受TP和TN影响。综上所述,松嫩平原西部草甸碱土施加有机肥后土壤盐碱程度降低,SOC、TN、TP含量和N/P增加,C/N降低,且施加有机肥改良15年的土壤供碳、供氮潜力达到最大。

土壤源热泵地埋管侧水系统优化运行研究

本文基于江苏无锡某典型厂房土壤源热泵空调项目的实测数据,以地源侧系统总能耗最低为目标,构建设备模型对地源水泵运行工况进行优化,并与两种传统控制策略的运行效果进行对比,据此提出进一步的优化建议。结果表明:基于负荷的优化控制策略,其节能效果要明显优于定频控制策略,冬夏季典型测试日平均节能率分别为28.33%和13.27%,相比于5℃温差变频策略节能了3.61%和2.21%。适当增大地埋管的埋管深度或管径,可以进一步提升该优化控制策略的节能效果。传统的定温差控制策略在负荷率大于60%时,可在5℃基础上将温差增加1~5℃以提升节能效果。

“离子交换法”测定硝酸盐氧同位素组成方法的改进

硝酸盐氮、氧同位素组成(δ^(15)N、δ^(18)O)被广泛应用于识别水体中硝酸盐的来源及其生化转化过程.离子交换技术作为主要分析方法之一,被大量应用于测定硝酸盐的氮同位素组成,然而在测定氧同位素组成时,由于该方法的样品处理过程复杂繁琐、耗时长(3~5天)等缺点限制了它的广泛应用.通过对原技术路线进行改进:将定量的BaCl_(2)直接加入到野外采集的水样中,消除含氧阴离子(SO_(4)^(2-)和PO_(4)^(3-))对测定NO_(3)^(-)离子δ^(18)O的干扰,然后再通过阴离子交换树脂吸附富集、HCl洗脱NO_(3)^(-)、Ag_(2)O中和,得到用于测试δ^(18)O的AgNO_(3)样品.与原路线相比,改进后方法的优势在于:(1)样品处理步骤由原来的5步缩短到了3步;(2)样品处理时长由3~5天缩短至1~2天;(3)减少了昂贵的化学试剂的用量;(4)减少了同位素的分馏.

稻秆生物炭对水体Pb^(2+)的吸附特性及机制定量化

采用吸附等温线和动力学等方法阐明了稻秆生物炭对水体Pb^(2+)的吸附特性,并通过元素分析、BET(Brunauer-Emmet-Teller)-N_(2)比表面积分析、Zeta电位、扫描电镜-能谱仪、傅立叶变换红外光谱、X射线衍射和X射线光电子能谱等分析手段,结合机制贡献比例计算方法,定性和定量地揭示了生物炭吸附机制。结果表明,在不同吸附温度20、30、40℃下,生物炭对Pb^(2+)的最大吸附量分别为233.48、236.00、237.50 mg/g,均符合Langmuir模型(R^(2)>0.96),属于单分子层吸附;当初始Pb^(2+)浓度为50、100、300 mg/L时,生物炭吸附平衡时间分别为30、90、360 min,均符合准二级动力学模型(R^(2)>0.95),以化学吸附为主。生物炭对Pb^(2+)吸附机制主要包括化学沉淀、离子交换、官能团络合和Cπ电子配位等4种作用,其中化学沉淀产物可能以Pb_(4)(CO_(3))_(2)(SO_(4))(OH)_(2)和PbCO_(3)为主,贡献比例为47.15%~50.81%,离子交换主要以Ca^(2+)和Mg^(2+)为主,贡献比例为32.82%~37.77%,这两者共同贡献比例范围为83.63%~84.92%,其余2种吸附机制共同占比15.03%~16.37%。生物炭对Pb^(2+)具有优良的吸附能力,可作为水体中重金属的优势吸附材料之一。

质子交换膜燃料电池引射器的设计及验证

为提高质子交换膜燃料电池系统引射器的引射性能,基于一款燃料电池系统的阳极氢气循环需求设计了一款引射器,并通过搭建CFD仿真模型,以引射器的5个关键参数为变量,结合燃料电池系统氢气子系统实际工况,分析引射器的关键尺寸参数变化对引射器性能的影响,获得了最优的引射器尺寸参数。以仿真优化结果为基础试制了一个样件,同时试制了4个对比样件进行对比测试。结果表明:混合段直径、喷嘴与混合段距离、混合段长度3个设计参数对引射器性能的影响最大,混合段直径、喷嘴与混合段的距离对应不同工况都有一个最优值;引射器二次侧入口氢气中含有的大量氮气和水蒸气,对引射器的计量比有很大的影响;相比之下,仿真优化后的引射器在不同工况都具有最优引射性能。

明代四川开中法的施行与实绩

明代四川开中法始于洪武四年(1371),沿着松潘—建昌一线展开,户部根据军情缓急,权宜开中。景泰以后开中地点集中于松潘,开中盐引种类限于川盐。商人从成都收买粮米,运至边仓上纳,然后在盐司支盐,可以获得一倍以上的利润。商人按照既定盐引官价,上纳相应价值的粮米,每年开中盐粮大约2.66万石,占松潘所需军饷的三分之一左右。开中法鼓励商人输挽粮米,减轻军民转运劳苦,缓解了边粮不足的问题,但商人纳粮价值少于纳银,官府获利不多。因此,正德元年之后,四川不再开中纳粮,户部将四川盐课全部折银征收,由商人代纳灶课,灶户偿还食盐。盐课折银共计7万余两,成为明后期四川提举司办纳岁额。

参苓白术散对腹泻幼鼠模型肠黏膜通道蛋白的影响及机制研究

目的探讨参苓白术散对腹泻幼鼠模型肠黏膜通道蛋白的影响及机制。方法将腹泻幼鼠模型(n=42,采用番泻叶药液灌胃进行建模)随机平分为三组,分别为模型组、低剂量参苓白术散组、高剂量参苓白术散组,三组分别给予参苓白术散0.0 g/kg(即0.9%氯化钠溶液)、1.2 g/kg、4.6 g/kg灌胃治疗,给药体积均为10 mL/kg,连续用药14 d,检测幼鼠肠黏膜通道蛋白-水通道蛋白8(AQP8)、跨膜转运蛋白钠氢交换体3(NHE3)囊性纤维化跨膜传导调节因子(CFTR)表达变化情况,观察幼鼠体质量、尿液乳果糖和甘露醇比值、小肠组织绒毛长度等变化情况。结果低剂量参苓白术散组、高剂量参苓白术散组治疗第7天、第14天的幼鼠体质量明显高于模型组(P<0.05),腹泻指数与模型组相比明显降低(P<0.05),高剂量参苓白术散组与低剂量参苓白术散组对比,差异有统计学意义(P<0.05)。低剂量参苓白术散组、高剂量参苓白术散组治疗第7天、第14天的尿液乳果糖和甘露醇比值明显低于模型组(P<0.05),高剂量参苓白术散组也低于低剂量参苓白术散组(P<0.05)。低剂量参苓白术散组、高剂量参苓白术散组治疗第14天的小肠组织绒毛长度高于模型组(P<0.05),隐窝深度明显低于模型组(P<0.05),高剂量参苓白术散组与低剂量参苓白术散组对比,差异有统计学意义(P<0.05)。低剂量参苓白术散组、高剂量参苓白术散组治疗第14天的小肠组织AQP8蛋白、NHE3蛋白相对表达水平高于模型组(P<0.05),CFTR蛋白相对表达水平低于模型组(P<0.05),低剂量参苓白术散组与高剂量参苓白术散组对比,差异有统计学意义(P<0.05)。结论参苓白术散在腹泻幼鼠模型中的应用能促进体质量的恢复,降低尿液乳果糖和甘露醇比值与腹泻指数,还可延长小肠组织绒毛长度与降低隐窝深度,同时可促进小肠组织AQP8蛋白、NHE3蛋白的表达,抑制CFTR蛋白的表达。

昆明市植烟土壤交换性钙镁特征分析

利用GPS定位在昆明市烤烟种植区采集了1000个代表性土壤样品,测定了其交换性钙、镁含量及钙镁比值。结果表明:①昆明市植烟土壤交换性钙、镁含量丰富,平均值分别为2728.36和294.71 mg/kg,土壤钙镁比值大于10而引起的镁潜在性缺乏比例占37.50%。②土壤交换性钙、镁含量和钙镁比随海拔高度的升高而呈下降趋势,低海拔植烟土壤的交换性钙、镁含量高于高海拔地区。③土壤质地对交换性钙、镁含量的影响不大,但总体表现出质地粘重的土壤钙镁比值相对较高。④土壤交换性钙、镁含量与土壤pH呈正相关关系。

黄河水中铅(Ⅱ)与悬浮粒子相互作用的研究

为了研究痕量金属铅在黄河水体中迁移转化规律以及黄河悬浮粒子承载铅的能力 ,进行了黄河水中铅 (Ⅱ )与悬浮粒子相互作用的实验。结果表明 :①铅以一价正离子形式与悬浮粒子进行阳离子交换 ,交换的pH范围在 3～ 7,当pH为 6时 ,离子交换率达到最大值 ;②铅离子浓度增加 ,离子交换率降低 ;③交换剂为转化沙时的离子交换率比未转化沙大 ;④可溶态痕量金属铅在黄河水中除了与悬浮粒子表面吸着交换进入固相外 。

沈阳市郊区蔬菜保护地土壤交换性钙镁含量及钙镁比值的变化

对沈阳市郊区43对蔬菜保护地与相邻的露地土壤中交换性Ca、Mg含量状况及Ca/Mg比值进行对比研究的结果表明:与露地土壤相比,保护地土壤交换性Ca平均含量下降6.38%,Ca/Mg比值下降10.34%,交换性Mg平均含量上升4.74%。蔬菜保护地及露地土壤的Ca/Mg比值与交换性Ca含量呈极显著相关(r分别为0.721和0.757,n=43,P<0.01),Ca/Mg比值与交换性Mg含量无显著相关性(r分别为-0.065和-0.117,n=43)。交换性Ca含量下降的主要原因是随蔬菜输出到系统外的Ca量相对较多、含钙肥料施用量减少及土壤pH下降;交换性Mg含量上升的主要原因是土壤中适宜的pH范围(5.0～6.5)有利于Mg以交换性形态存在,土壤中高浓度的Ca2+、K+、NH+4抑制了蔬菜对Mg2+的选择性吸收。