Determination of plasma concentrations of propofol associated with 50% reduction in postoperative nausea

BACKGROUND: Subhypnotic doses of propofol possess direct antiemetic properties. The authors sought to determine the plasma concentration of propofol needed to effectively manage postoperative nausea and vomiting. METHODS: Patients aged 18-70 yr who were classified as American Society of Anesthesiologists physical status 1 or 2 and had surgery during general anesthesia were approached for the study. Only patients who had nausea (verbal rating score > 5 on a 0- to 10-point scale), retching, or vomiting in the postanesthetic care unit participated. Propofol was administered to these patients to achieve target plasma concentrations of 100, 200, 400, and 800 ng/ml using a computer-assisted continuous infusion device. Target concentrations were increased every 15 min until patients described at least a 50% reduction in symptoms on the verbal rating score. An arterial blood sample was obtained at each step. The measured plasma propofol concentrations were used to analyze data. Blood pressure, heart and respiratory rates, arterial blood saturation, sedation score, and overall satisfaction with treatment were recorded. RESULTS: Of the 89 patients who consented to the study, 15 patients met entry criteria and were enrolled. Five of these patients also had retching or vomiting when they entered the study. Fourteen patients responded successfully to treatment. One patient did not achieve the required response at plasma concentrations of 830 ng/ml. Hence the success rate for the treatment of postoperative nausea and vomiting was 93%. Among patients who responded, the median plasma concentration associated with an antiemetic response was 343 ng/ml. There was no difference in sedation scores from baseline and no episodes of desaturation. Hemodynamic parameters were stable during the study. CONCLUSIONS: Propofol is generally efficacious in treating postoperative nausea and vomiting at plasma concentrations that do not produce increased sedation. Simulations indicate that to achieve antiemetic plasma propofol concentrations of 343 ng/ml, a bolus dose of 10 mg followed by an infusion of approximately 10 microg x kg(-1) x min(-1) are necessary.     

Molecular electronics: strategies and progress in China

The field of molecular electronics is being used to explore a new generation of electronic devices and bionic information processing systems in China. Molecular research in China covers three different levels: (1) nanotechnology for molecular assembly in both fundamental and practical applications; (2) molecular devices for sensing, memory, switching, and actuation; (3) and theoretical studies on novel computing principles. In this article the authors review the main achievements in molecular electronics, but due to space limitations, it is impossible to cover all important results     

基于数码织造技术的"织成"服装面料的创新开发

在分析传统“织成”的生产技术基础上，提出运用现代数码织造技术开发“织成”服装面料的新思路，为传统织物的保护、继承和发扬探索一条新的途径，同时围绕“织成”服装面料的设计应用与开发，讨论了纹样设计、组织选择、色卡配合等具体设计方法，并通过数码织造，进行了产品的实验，对“织成”传统的生产工艺进行优化的途径做出了初步的探讨。为了应用于“织成”服装面料，选用真丝仿真彩色织物色卡，并通过建立相应的计算机颜色与组织模型，使由色经、色纬及组织结合所表现出的织物色能够与计算机屏幕显示出的纹样色快速、准确地达成一致。     

A Novel Flow Profiling Approach Using Permanent Downhole Pressure Gauges

Flow profiling through permanent downhole pressure gauge, a novel and unique application, is proposed in the present paper. Theoretical development of the new technique is first provided. Example studies are then given to illustrate the application of the technique. Application scenarios, practical issues, as well as key impacting parameters are also addressed. Finally, a field case study implementing the new technique for a long horizontal well is performed to demonstrate how the production profiles calculated from permanent downhole gauge (PDG) data compare closely to the results from a recent production logging (PLT) survey which was expensive and mechanically risky yet turned out to be unsatisfactory.

The technique could be applied to real-time production and injection profiling for different well configurations (vertical, horizontal, deviated, and multilateral) and bring tremendous financial benefits through replacing conventional production logging surveys that could be cost-extensive for horizontal or multilateral wells offshore.     

无限稀活度系数的推算

应用ＵＮＩＦＡＣ模型导出了甲醇氯苯和苯正丙醇体系各组元的无限稀活度系数的计算式．由此回归的Ｗｉｌｓｏｎ或ＮＲＴＬ参数预测的活度系数值与根据气液平衡实验获得的结果符合良好．     

窄馏分己烷生产装置技术改造

针对工业己烷产品存在的质量问题，通过计算机工艺模拟和方案设计，确定了新的分馏流程，增设了己烷精馏塔及加氢脱苯设施，解决了己烷产品馏程和苯含量不合格的问题。改造后己烷产品质量优于GB17602－1998要求，且收率由1.4%提高到6.6%。     

铁矿地下开采对铁路路基稳定性的影响分析

分析了小王庄铁矿地下开采对大秦铁路线路基稳定性的影响因素，建立了适于采矿工程模拟的FLAC数值模拟模型，通过数值模拟分析，计算出铁路附近的应力变化数值，模拟结果表明，小王庄铁矿地下开采引起的大秦铁路附近的位移变化为10-4 m数量级，几乎无影响，这对矿山的建设和正常生产有重要的参考价值。     

造纸高岭土增白工艺研究

造纸高岭土要求具备高白度、高纯度及低黏度等良好特性，然而目前我国高岭土增白的研究多针对煤系硬质高岭土，而较少针对软质高岭土。作者选取综合质量较好但白度仍待提高的茂名软质高岭土进行增白研究，通过研磨、连二亚硫酸盐法、酸处理和煅烧等方法，可得到白度〉92％的高岭土精粉。     

多级AO+潜流湿地对生活污水中的EDCs及常规污染物的去除试验研究

针对生活污水中内分泌干扰物（EDCs）可能引起的生物生态危害问题,以类固醇类内分泌干扰物为处理对象,应用生物生态耦合技术,进行多级AO+潜流式人工湿地处理试验,考察了水力停留时间（HRT）对COD_Cr、氨氮（NH₄⁺-N）、总磷（TP）、总氮（TN）等污染物去除影响,同时,采用固相萃取法和GC-MS检测各反应器进、出水中雌酮（E1）、17β-雌二醇（E2）、雌三醇（E3）、17α-乙炔基雌二醇（EE2）4种内分泌干扰物浓度变化。结果表明,当多级AO与湿地的HRT分别为9.5 h、10.3 d时,多级AO+潜流式人工湿地对COD_Cr、NH₄⁺-N、TP、TN等污染物去除率可分别达78.64%、97.16%、91.84%、90.55%,出水浓度均低于《太湖地区城镇污水处理厂及重点工业行业主要水污染物排放限值》（DB 32/1072-2017）排放浓度限值。多级AO+人工湿地对内分泌干扰物E1、E2、E3和EE2的总去除率可分别达96.04%、92.45%、85.09%、88.38%;其中,多级AO系统对E1、E2、E3和EE2的去除率分别达到75.50%、72.00%、65.08%和63.35%,且一级好氧池对4种EDCs的去除贡献最大,均为27%以上;湿地系统对前3种EDCs的去除率约为20%、EE2为25%。Alpha多样性指数分析表明,好氧池物种数量和多样性多于未加EDCs前,门分类、属分类的微生物群落物种及其丰度分析表明,群落门水平、属水平相对丰度均发生变化,其中,增加的优势菌种可能对系统中EDCs的去除起到了促进作用。     

混凝土粗糙面形貌特征参数与节理粗糙度系数关系研究

裂缝面粗糙程度是描述其表面形貌的重要参数。基于三维扫描技术获取混凝土裂缝面的坐标点云数据,等间隔选取各裂缝面11条轮廓线,计算各轮廓线粗糙轮廓指数Rp、形貌线伸长指数δ和粗糙角i等特征参数,研究采样间隔SI对二维节理粗糙度系数JRC的影响;建立JRC与二维特征参数Rp、δ、i之间的函数关系、三维JRC3D与三维特征参数之间的关系。结果表明：JRC与SI呈二次函数关系,当SI为0.2 ～ 1.2mm时,随SI减小,JRC增大;JRC与Rp、δ分别呈二次函数和对数关系;JRC与二维特征参数中的粗糙角iZ2呈正相关关系。建议Rp作为二维节理粗糙度系数表征指标。JRC3D与三维特征参数的最大构造深度Rz相关性最好,拟合公式平方根R2为0.9109。提出的表征公式与已有成果最大平均相对误差MRE、平均绝对误差MAE和均方根误差RMSE分别为1.790%、0.316mm和0.408mm。说明提出的表征公式是合理的,适用于混凝土裂缝面粗糙度估算。