• 【Tamarix ramosissima的水热处理和酶促水解: 作为生物精炼概念中的转化方法的过程评估。】 复制标题 收藏 收藏
    DOI:10.1016/j.biortech.2012.08.143 复制DOI
    作者列表:Xiao LP,Shi ZJ,Xu F,Sun RC
    BACKGROUND & AIMS: :The present work investigated the effects of hydrothermal treatment (HTT) of Tamarix ramosissima by determination of sugar and inhibitor formation in the liquid fraction, and chemical and morphological changes of the pretreated solid material coupled with an evaluation of enzymatic hydrolysis. HTT was carried out in a batch reactor system at a maximal temperature (TMAX 180-240 °C) and evaluated for severities logRo ranging from 2.40 to 4.17. The liquid fractions were analyzed by HPLC, GPC, and GC-MS. The morphology and composition of the solid residues were characterized using an array of techniques, such as SEM, XRD, BET surface area, and CP/MAS (13)C NMR. Using a variety of tools, we have developed a better understanding of how HTT process affects biomass structure and cellulose properties that impact on its digestibility. These results provided new insights into the factors limiting enzymatic digestibility and mechanism of biomass deconstruction during hydrothermal process.
    背景与目标: : 目前的工作通过测定液体馏分中的糖和抑制剂的形成以及预处理固体材料的化学和形态变化以及酶水解的评估,研究了Tamarix ramosissima的水热处理 (HTT) 的影响。在间歇反应器系统中在最高温度 (TMAX 180-240 °C) 下进行HTT,并评估范围为2.40至4.17的严重度。通过HPLC,GPC和gc-ms分析液体级分。使用一系列技术 (例如SEM,XRD,BET表面积和CP/MAS (13)C NMR) 表征了固体残基的形态和组成。使用各种工具,我们对HTT过程如何影响生物质结构和纤维素特性 (影响其消化率) 有了更好的了解。这些结果为水热过程中限制酶消化率的因素和生物质解构的机理提供了新的见解。
  • 【快速、稳健的尿液中低浓度白蛋白测定方法。】 复制标题 收藏 收藏
    DOI: 复制DOI
    作者列表:Medcalf EA,Newman DJ,Gorman EG,Price CP
    BACKGROUND & AIMS: :We describe a rapid particle-enhanced turbidimetric immunoassay for albumin in urine. Intra- and interassay CVs were less than 5% and less than 10%, respectively, the detection limit is 2 mg/L, and the working range extends to 200 mg/L. Mean analytical recovery of albumin added to centrifuged urines was 100% (SD 10.6%), and, when results were compared with those by the Pharmacia RIA, the correlation coefficient was 0.99. The working reagents are stable for at least six months; thus this assay is suited for both batch and urgent analysis.
    背景与目标: : 我们描述了尿液中白蛋白的快速颗粒增强比浊法免疫测定。测定内和测定间CVs分别小于5% 和小于10%,检出限为2 mg/L,工作范围扩大至200 mg/L。添加到离心尿液中的白蛋白的平均分析回收率为100% (SD 10.6%),并且当将结果与通过Pharmacia RIA进行比较时,相关系数为0.99。工作试剂至少稳定六个月; 因此,该测定法适用于分批和紧急分析。
  • 【提出了一种用有限元方法模拟无骨水泥中骨向内生长过程的方法。】 复制标题 收藏 收藏
    DOI:10.1016/j.medengphy.2012.10.010 复制DOI
    作者列表:Tarala M,Janssen D,Verdonschot N
    BACKGROUND & AIMS: :In cementless total hip arthroplasty, long-term implant stability is achieved by bone ingrowth. The strength of the new bond gradually increases in time, due to bone maturation and progression of ingrowth. In finite element simulations, osseointegration generally is implemented as an instant change in the mechanical behavior of the implant-bone interface, although this is a simplified interpretation of the bone ingrowth process. The aim of the present study was to build on previous bone ingrowth simulations and propose a new methodology to simulate bone ingrowth as a time-dependent process. We developed an algorithm to calculate the strength of the local implant-bone bond based of the magnitude of interface micromotions and gaps in time. Our algorithm was subsequently tested in multiple hip reconstructions in which the bone quality and implant-bone contact area were varied. The results of the simulations showed that in the ideal situation (good bone quality and no interface gaps), 91% of implant area could achieve ingrowth, while in the worst case only 17% of implant area showed ingrowth. The initial contact area had a significant effect on ingrowth, overruling the effect of variations in bone quality. The progression of ingrowth had a stabilizing effect on adjacent regions, especially in the high contact area cases. Further development and validation of the presented algorithm requires more information on the nature of the relation between the ingrowth rate and the magnitude of micromotions and gap.
    背景与目标: : 在无骨水泥全髋关节置换术中,植入物的长期稳定性是通过骨向内生长来实现的。由于骨骼的成熟和向内生长的进展,新键的强度随时间逐渐增加。在有限元模拟中,骨整合通常是作为植入物-骨界面的机械行为的即时变化来实现的,尽管这是对骨向内生长过程的简化解释。本研究的目的是在以前的骨向内生长模拟的基础上,提出一种新的方法来模拟骨向内生长,这是一个与时间有关的过程。我们开发了一种算法,可以根据界面微动的大小和时间间隙来计算局部植入物-骨键的强度。随后,我们的算法在多次髋关节重建中进行了测试,其中骨质量和植入物-骨接触面积发生了变化。模拟结果表明,在理想情况下 (良好的骨质量和无界面间隙),植入物区域的91% 可以实现向内生长,而在最坏的情况下,只有17% 的植入物区域显示向内生长。初始接触面积对向内生长有显着影响,从而推翻了骨质量变化的影响。向内生长的进程对相邻区域具有稳定作用,尤其是在高接触面积的情况下。提出的算法的进一步开发和验证需要更多有关向内生长速率与微动和间隙大小之间关系的性质的信息。
  • 【为考虑器官捐赠选择的家庭提供支持: 一种创新的培训方法。】 复制标题 收藏 收藏
    DOI: 复制DOI
    作者列表:Jacoby L,Crosier V,Pohl H
    BACKGROUND & AIMS: :Families must make decisions about organ donation for a loved one during intensely emotional circumstances in the hospital, where support from others is crucial to their coping. Research about families' experiences during the decision-making process regarding donating their loved ones' organs has shown that quality of hospital care and receiving psychosocial support are important factors influencing their decision. Typically, a donation coordinator from the local organ procurement organization approaches the family about the option of donation, whereas the role of medical and nursing staff is to convey diagnostic and prognostic information to the family. Currently, no requirement is in place for training of professional staff in communication skills for approaching and interacting with families about organ donation. This article discusses a simulated training method in empathic communication used for supporting families who are approached about organ donation. This innovative method can be adapted to and should be tested with professional audiences.
    背景与目标: : 家庭必须在医院里情绪激动的情况下决定为亲人捐赠器官,而其他人的支持对他们的应对至关重要。对家庭在捐赠亲人器官的决策过程中的经历的研究表明,医院护理质量和接受社会心理支持是影响其决策的重要因素。通常,来自当地器官采购组织的捐赠协调员会向家人介绍捐赠的选择,而医疗和护理人员的作用是向家人传达诊断和预后信息。目前,没有要求对专业人员进行沟通技能培训,以便就器官捐赠问题与家人接触和互动。本文讨论了一种在移情交流中进行模拟训练的方法,该方法用于支持与器官捐赠有关的家庭。这种创新方法可以适应专业观众,也应该接受专业观众的测试。
  • 【改进的血浆8-异前列腺素测量方法以及与习惯性饮酒和吸烟的关联分析。】 复制标题 收藏 收藏
    DOI:10.3748/wjg.v12.i36.5846 复制DOI
    作者列表:Kitano S,Hisatomi H,Hibi N,Kawano K,Harada S
    BACKGROUND & AIMS: AIM:To develop a simple and accurate method for quantifying 8-isoprostane in plasma by employing a combination of two-step solid-phase extraction of samples and a commercially available ELISA kit, and by this method to examine the effects of drinking and smoking habits against the levels of plasma 8-isoprostane in healthy Japanese volunteers. METHODS:Plasma 8-isoprostane was extracted with ODS gel suspension followed by NH(2) Sep-Pak column. The 8-isoprostane fractions were assayed using a commercially available ELISA kit. We measured plasma 8-isoprostane levels in 157 healthy Japanese volunteers divided into three groups (64 non-habitual drinkers, 56 moderate drinkers and 37 habitual drinkers) according to their alcohol consumption per week. Genotypes of aldehyde dehydrogenase 2 (ALDH2) were also determined to investigate the plasma 8-isoprostane levels with reference to drinking habits. In addition, the plasma 8-isoprostane levels of 96 non-smokers and 61 smokers from the same subjects were compared. RESULTS:Our method fulfilled all the requirements for use in routine clinical assays with respect to sensitivity, intra- and inter-assay reproducibility, accuracy and dynamic assay range. Significant increases of plasma 8-isoprostane levels were observed in female habitual drinkers when compared with those of non-habitual drinkers (t = 5.494, P<0.0001) as well as moderate drinkers (t = 3.542, P<0.005), and 8-isoprostane levels were also significantly different between ALDH2*2/1 and ALDH2*1/1 in the female habitual drinkers (t = 6.930, P<0.0001), suggesting that excessive drinking of alcohol may increase oxidization stress, especially in females. On the contrary, no significant difference of the plasma 8-isoprostane levels was observed between non-smokers and smokers. CONCLUSION:Our present method was proved to be a simple and accurate tool for measuring plasma 8-isoprostane. However, the clinical utility of plasma 8-isoprostane for drinking and smoking habits was limited since elevated 8-isoprostane levels were observed in female heavy drinkers, and no association was found between smokers and nonsmokers.
    背景与目标:
  • 【抗逆转录病毒方案复杂性指数。一种量化方案复杂性的新方法。】 复制标题 收藏 收藏
    DOI:10.1097/QAI.0b013e31811ed1f1 复制DOI
    作者列表:Martin S,Wolters PL,Calabrese SK,Toledo-Tamula MA,Wood LV,Roby G,Elliott-DeSorbo DK
    BACKGROUND & AIMS: BACKGROUND:Individuals with HIV disease often must adhere to complex medication regimens. To date, regimen complexity has not been examined in the literature using standardized procedures incorporating all important elements of antiretroviral (ARV) regimens. OBJECTIVE:This article presents a novel method of quantifying regimen complexity using objective criteria addressing the factors that may complicate adherence to ARV regimens. METHODS:Part 1 of this article describes the development of the Antiretroviral Regimen Complexity (ARC) Index scoring system. Based on input from pediatric and adult patients, caregivers of pediatric patients, and health care professionals, this comprehensive system includes the number of medications, dosing schedules, administration methods, special instructions, and required preparations associated with ARV regimens. Weights are applied for each of these factors to produce an overall score representing the regimen's level of complexity. Part 2 of this article presents reliability and validity data for the system. RESULTS:The ARC Index demonstrates excellent test-retest and interrater reliability as well as strong construct and discriminant validity. An on-line version of this system minimizes computation errors. CONCLUSIONS:Although modifications may be necessary for patients requiring nonstandard dosing instructions, preliminary evidence supports the utility of this measure as a reliable and valid indicator of the complexity of antiretroviral treatment regimens.
    背景与目标:
  • 【胎盘摘除法对剖宫产术后感染发生率的影响。】 复制标题 收藏 收藏
    DOI:10.1016/s0002-9378(97)70342-9 复制DOI
    作者列表:Lasley DS,Eblen A,Yancey MK,Duff P
    BACKGROUND & AIMS: OBJECTIVE:Our purpose was to determine whether the incidence of postoperative endometritis and wound infection is associated with the method of placental removal at the time of cesarean section.

    STUDY DESIGN:Parturients undergoing cesarean delivery were prospectively randomized to have the placenta removed manually or spontaneously. Patients were excluded from participation if they had received intrapartum prophylactic antibiotics or had been determined to have chorioamnionitis. After delivery of the infant women in the manual group had the placenta extracted by the primary surgeon, whereas women in the spontaneous group had the placenta delivered by gentle traction on the umbilical cord. All study subjects received perioperative prophylactic antibiotics. The primary outcome variable was a postcesarean infection, defined as postecsarean endometritis or wound cellulitis requiring drainage and antibiotic therapy.

    RESULTS:A total of 333 women were enrolled in the investigation, with 165 assigned to the manual removal group and 168 allocated to have spontaneous removal. There were no statistically significant differences in mean gestational age, frequency or duration of ruptured membranes, frequency or duration of labor, or mean number of vaginal examinations between the two study groups. Postoperative infections occurred in 25 of 168 (15%) women in the spontaneous delivery group compared with 44 of 165 (27%) women in which the placenta was manually extracted (relative risk 0.6, 95% confidence interval 0.4 to 0.9, p = 0.01). Subset analysis of patients delivered with ruptured membranes similarly demonstrated a statistically significant reduction in the incidence of postoperative infections with spontaneous placental removal compared with manual extraction (20% vs. 38%, relative risk 0.5, 95% confidence interval 0.3 to 0.9, p = 0.02). There was a similar trend toward a reduction in postdelivery infections associated with spontaneous placental removal in women with intact membranes; however, this difference did not attain statistical significance.

    CONCLUSIONS:Spontaneous delivery of the placenta after cesarean delivery is associated with a decrease in the incidence of postcesarean infections.

    背景与目标: 目的 : 我们的目的是确定术后子宫内膜炎和伤口感染的发生率是否与剖宫产时胎盘摘除的方法有关。
    研究设计 : 进行剖宫产的产妇被随机分配给人工或自发摘除胎盘。如果患者接受了产时预防性抗生素治疗或已确定患有绒毛膜羊膜炎,则被排除在参与治疗之外。分娩后,手动组的婴儿妇女由初级外科医生提取胎盘,而自发组的妇女则通过脐带上的轻柔牵引来递送胎盘。所有研究对象均接受围手术期预防性抗生素治疗。主要结局变量是剖宫产后感染,定义为剖宫产后子宫内膜炎或需要引流和抗生素治疗的伤口蜂窝织炎。
    结果 : 共有333名妇女参加了调查,将165分配给手动移除组,并将168分配为具有自发移除。两个研究组之间的平均胎龄,破裂的频率或持续时间,分娩的频率或持续时间或阴道检查的平均数量没有统计学上的显着差异。自发分娩组168例 (15% 例) 妇女中有25例发生术后感染,而人工提取胎盘的165例 (27% 例) 妇女中有44例发生术后感染 (相对危险0.6,95% 置信区间0.4至0.9,p = 0.01)。类似地,对患有破裂膜的患者进行的子集分析表明,与手动拔除相比,自发胎盘的术后感染发生率在统计学上显着降低 (20% 与38%,相对风险0.5,95% 置信区间0.3 0.9,p = 0.02)。在具有完整膜的女性中,与自发胎盘摘除相关的分娩后感染减少的趋势相似; 但是,这种差异没有统计学意义。
    结论 : 剖宫产后胎盘的自发分娩与剖宫产后感染的发生率降低有关。
  • 【支原体感染和类风湿性关节炎: 使用免疫印迹和超灵敏聚合酶链反应检测方法分析它们的关系。】 复制标题 收藏 收藏
    DOI:10.1002/1529-0131(199707)40:7<1219::AID-ART5>3.0.C 复制DOI
    作者列表:Hoffman RW,O'Sullivan FX,Schafermeyer KR,Moore TL,Roussell D,Watson-McKown R,Kim MF,Wise KS
    BACKGROUND & AIMS: OBJECTIVE:To examine the relationship between infection with Mycoplasma and the development of rheumatoid arthritis (RA) and juvenile rheumatoid arthritis (JRA).

    METHODS:Immunoblotting of patient synovial fluid and sera on detergent-phase membrane protein extracts of various Mycoplasma species was carried out to learn whether patients exhibited serologic evidence of previous exposure to mycoplasmas. Moreover, an ultrasensitive polymerase chain reaction (PCR) method was developed for assessing whether Mycoplasma DNA could be detected in synovial fluid from patients and controls.

    RESULTS:Immunoblotting provided serologic evidence of previous Mycoplasma exposure in patients and controls. The genus-specific PCR detected known human Mycoplasma species and could reliably detect <5 copies of Mycoplasma hominis, Mycoplasma fermentans, or a molecular mimic control in synovial fluid. Repeat testing revealed no evidence of Mycoplasma DNA in patient synovial samples.

    CONCLUSION:This study provided serologic evidence suggesting that, while previous exposure to Mycoplasma was common, there was no detectable persistence of Mycoplasma DNA in the synovial fluid or tissue of patients with RA or JRA.

    背景与目标: 目的 : 检查支原体感染与类风湿关节炎 (RA) 和幼年类风湿性关节炎 (JRA) 的发展之间的关系。
    方法 : 对各种支原体的去污剂相膜蛋白提取物进行了患者滑液和血清的免疫印迹,以了解患者是否表现出先前暴露于支原体的血清学证据。此外,开发了一种超灵敏的聚合酶链反应 (PCR) 方法,用于评估是否可以在患者和对照组的滑液中检测到支原体DNA。
    结果 : 免疫印迹提供了患者和对照组先前暴露于支原体的血清学证据。属特异性PCR检测到已知的人类支原体物种,并且可以可靠地检测滑液中 <5个拷贝的人支原体,发酵支原体或分子模拟对照。重复测试显示患者滑膜样本中没有支原体DNA的证据。
    结论 : 这项研究提供了血清学证据,表明尽管先前暴露于支原体很常见,RA或JRA患者的滑液或组织中没有可检测到支原体DNA的持久性。
  • 【一种基于动物组织作为生物容器的用于超微结构研究的精子样品处理的新方法。】 复制标题 收藏 收藏
    DOI:10.1002/jemt.20466 复制DOI
    作者列表:Junquera C,Colás C,Martínez-Ciriano C,Serrano P,Castiella T,Cebrian-Perez JA,Muiño-Blanco T
    BACKGROUND & AIMS: :The study of the ultrastructure of spematozoa by means of transmission electron microscopy often presents with problems of interpretation according to the method employed, depending on whether samples are either centrifuged previously to the fixation or immersed in viscous gels. The major problems of interpretation are: changes in the location of vesicles originated during the maturation process and modifications in the adsorption of seminal plasma proteins to the sperm membrane surface. The aim of our study is to communicate an original new method for the treatment of spermatozoa for ultrastructural study. Our method is based on the use of animal tissues as biological containers, inside which the spermatic suspensions are included. We developed this method using fresh sperm samples taken from mature Rasa aragonesa rams. As biological container, we used 2.5-cm long segments of the intestine of 1-week-old chickens (Gallus gallus) (diameter around 4 mm). To avoid any influence of digestive enzymes of the mucosa on the sperm surface, we put each intestine fragment inside out by means of microdissection forceps under bifocal optical microscope and cold light. One of the edges was tied with thin suture silk. The sperm suspension was injected in the optimal experimental condition and amount. Finally, the still open edge of the intestine segment was tied with silk in the same way as the other segment edge. By using this technique, we can perform a suitable morphological study at an ultrastructural level. In addition, the functional relationship of the ultrastructural components of the target cells is correctly preserved.
    背景与目标: : 通过透射电子显微镜研究spematozoa的超微结构通常会根据所采用的方法出现解释问题,具体取决于样品是先离心到固定物还是浸入粘性凝胶中。解释的主要问题是: 在成熟过程中引起的囊泡位置的变化以及精浆蛋白在精子膜表面吸附的改变。我们研究的目的是为超微结构研究提供一种治疗精子的原始新方法。我们的方法基于将动物组织用作生物容器,其中包括精索悬浮液。我们使用从成熟的Rasa aragonesa公羊中采集的新鲜精子样本开发了这种方法。作为生物容器,我们使用了1周大鸡 (Gallus gallus) 的2.5厘米长的肠段 (直径约4毫米)。为了避免粘膜消化酶对精子表面的任何影响,我们在双焦点光学显微镜和冷光下通过显微解剖钳将每个肠碎片向内放置。其中一个边缘用细细的缝合丝绑着。以最佳实验条件和数量注射精子悬浮液。最后,以与另一段边缘相同的方式用丝将肠段的仍然开放的边缘绑扎。通过使用这种技术,我们可以在超微结构水平上进行适当的形态学研究。此外,正确保留了靶细胞超微结构成分的功能关系。
  • 【[酵母对氟康唑的敏感性测试: 使用25微克氟康唑纸盘的标准化琼脂扩散法的建议]。】 复制标题 收藏 收藏
    DOI:10.1111/j.1439-0507.1996.tb00524.x 复制DOI
    作者列表:Schmalreck AF,Kottmann I
    BACKGROUND & AIMS: This paper gives a proposal for a standardised agar diffusion susceptibility testing method with 25 micrograms fluconazole discs. The methodology compiles the results of several years of work to develop a reliable and reproducible routine-method for the microbiology laboratory. In this proposal, in addition, the critics and experiences of a collaborative study for susceptibility testing of fluconazole with 21 laboratories from Germany and Austria are included.

    背景与目标: 本文提出了一种使用25微克氟康唑圆盘的标准化琼脂扩散敏感性测试方法的建议。该方法汇编了几年工作的结果,为微生物实验室开发了一种可靠且可重复的常规方法。此外,在该提案中,还包括与来自德国和奥地利的21个实验室进行的氟康唑药敏试验合作研究的批评家和经验。
  • 【欢乐-悲伤: 使用解析研究方法的研究。】 复制标题 收藏 收藏
    DOI:10.1177/089431849701000208 复制DOI
    作者列表:Parse RR
    BACKGROUND & AIMS: The purpose of this research was to uncover a structure of the lived experience of joy-sorrow using the Parse research method. Eleven women over 65 years of age volunteered to participate in the study by engaging in audio- and videotaped dialogues with the researcher about the phenomenon. The structure of the lived experience of joy-sorrow was found to be pleasure amid adversity emerging in the cherished contentment of benevolent engagements. Recommendations for further research and practice are specified.

    背景与目标: 这项研究的目的是使用Parse研究方法揭示欢乐悲伤的生活体验的结构。11名65岁以上的女性自愿参加了这项研究,与研究人员就这一现象进行了录音和录像对话。人们发现,欢乐悲伤的生活经历的结构是在对仁慈参与的珍惜满足中出现的逆境中的快乐。指定了进一步研究和实践的建议。
  • 【人血清总睾酮的同位素稀释液相色谱-串联质谱候选参考方法。】 复制标题 收藏 收藏
    DOI:10.1373/clinchem.2012.190934 复制DOI
    作者列表:Botelho JC,Shacklady C,Cooper HC,Tai SS,Van Uytfanghe K,Thienpont LM,Vesper HW
    BACKGROUND & AIMS: BACKGROUND:We developed and evaluated a candidate reference measurement procedure (RMP) to standardize testosterone measurements, provide highly accurate and precise value assignments for the CDC Hormone Standardization Program, and ensure accurate and comparable results across testing systems and laboratories. METHODS:After 2 liquid/liquid extractions of serum with a combination of ethyl acetate and hexane, we quantified testosterone by isotope-dilution liquid chromatography-tandem mass spectrometry with electrospray ionization in the positive ion mode monitoring 289→97 m/z (testosterone) and 292→112 m/z ((3)C(13) testosterone). We used calibrator bracketing and gravimetric measurements to give higher specificity and accuracy to serum value assignments. The candidate RMP was evaluated for accuracy by use of NIST-certified reference material SRM971 and validated by split-sample comparison to established RMPs. We evaluated intraassay and interassay imprecision, measurement uncertainty, potential interferences, and matrix effects. RESULTS:A weighted Deming regression comparison of the candidate RMP to established RMPs showed agreement with no statistical difference (slope 0.99, 95% CI 0.98-1.00, intercept 0.54, 95% CI -1.24 to 2.32) and a bias of ≤0.3% for NIST SRM971. The candidate RMP gave maximum intraassay, interassay, and total percent CVs of 1.5%, 1.4%, and 1.7% across the concentrations of testosterone typically found in healthy men and women. We tested structural analogs of testosterone and 125 serum samples and found no interferences with the measurement. CONCLUSIONS:This RMP for testosterone can serve as a higher-order standard for measurement traceability and can be used to provide an accuracy base to which routine methods can be compared in the CDC Hormone Standardization Program.
    背景与目标:
  • 【从大肠杆菌重组菌株中表达和隔离人支原体精氨酸脱亚胺酶的改进方法。】 复制标题 收藏 收藏
    DOI:10.1016/j.jbiotec.2013.06.025 复制DOI
    作者列表:Fayura LR,Boretsky YR,Pynyaha YV,Wheatley DN,Sibirny AA
    BACKGROUND & AIMS: :Arginine deiminase is a promising anticancer drug active against melanoma, hepatocarcinoma and other tumors. Recombinant strains of Escherichia coli that express arginine deiminase from pathogenic bacteria Mycoplasma have been developed. However, production costs of heterologous arginine deiminase are high due to use of an expensive inducer and extraction buffer, as well as using diluted culture for enzyme induction. We report on a new advanced protocol for Mycoplasma hominis arginine deiminase expression, extraction and renaturation. The main improvements include manipulation with dense suspensions of E. coli, use of lactose instead of isopropyl β-D-1-thiogalactopyranoside as an inducer and a cheaper but not less efficient buffer for solubilization of arginine deiminase inclusion bodies. In addition, supplementation of the storage culture medium with glucose and substrate (arginine) significantly stabilized the recombinant arginine deiminase producer. Homogenous preparations of recombinant arginine deiminase were obtained using anion-exchange and hydrophobic chromatography. The purified enzyme retained a specific activity of 30-34 U/mg for 12 months when stored at 4°C in 20 mM sodium phosphate buffer pH 7.2 containing 1 M NaCl.
    背景与目标: 精氨酸脱亚胺酶是一种对黑色素瘤,肝癌和其他肿瘤有活性的有前途的抗癌药物。已经开发出从致病菌支原体中表达精氨酸脱亚胺酶的重组大肠杆菌菌株。然而,由于使用昂贵的诱导剂和提取缓冲液以及使用稀释的培养物进行酶诱导,异源精氨酸脱亚胺酶的生产成本很高。我们报告了一种新的先进方案,用于人型支原体精氨酸脱亚胺酶的表达,提取和复性。主要改进包括使用大肠杆菌的致密悬浮液进行操作,使用乳糖代替异丙基 β-d-1-硫代半乳糖吡喃糖苷作为诱导剂,以及更便宜但效率较低的缓冲液,用于溶解精氨酸脱亚胺酶包涵体。此外,补充葡萄糖和底物 (精氨酸) 的储存培养基可显着稳定重组精氨酸脱亚胺酶生产者。使用阴离子交换和疏水色谱法获得重组精氨酸脱亚胺酶的均质制剂。当在4 °C下储存在含有1mnacl的20 mm磷酸钠缓冲液pH 7.2中时,纯化的酶在12个月内保持30-34u/mg的比活性。
  • 【学龄前儿童数字饮食估计方法的有效性。】 复制标题 收藏 收藏
    DOI:10.1016/j.jand.2017.05.005 复制DOI
    作者列表:Nicklas T,Islam NG,Saab R,Schulin R,Liu Y,Butte NF,Apolzan JW,Myers CA,Martin CK
    BACKGROUND & AIMS: BACKGROUND:The validity of using the Remote Food Photography Method (RFPM) for measuring food intake of minority preschool children's intake is not well documented. OBJECTIVE:Our aim was to determine the validity of intake estimations made by human raters using the RFPM compared with those obtained by weighing all foods and beverages consumed by 3- to 5-year-old children (weighed method). DESIGN:We conducted a cross-sectional observational study. PARTICIPANTS/SETTINGS:A convenience sample of 54 3- to 5-year-old Hispanic and African-American children were observed during a 12-hour period at Baylor Metabolic Research Unit between June 2013 and January 2014. MAIN OUTCOME MEASURES:All foods/beverages consumed by the children were provided by Baylor research coordinators who took and wirelessly transmitted before-and-after pictures of the trays to trained human raters at the Pennington Biomedical Research Center who estimated grams consumed. Energy and macronutrients were calculated using the Food and Nutrient Database for Dietary Studies or food facts data provided by manufacturers. STATISTICAL ANALYSES:Paired t test, mean differences, and Bland-Altman limits of agreement were performed. RESULTS:Compared to the weighed method, the rater method significantly overestimated total intake by 34±71 g (P<0.0001), with a mean percent error of 2.9% (root mean square error=7.1%), and total energy intake by 75±102 kcal (P<0.0001), with a mean percent error of 7.5% (root mean square error=12.3%). The standard error for the macronutrient intakes ranged from 11.0% to 20.2%. The Bland-Altman approach demonstrated a positive slope for the rater method relative to the weighed method for total intake in grams (P=0.006), carbohydrate (P=0.01), and protein (P=0.01) (ie, magnitude of the bias increased with increasing intakes). CONCLUSIONS:The rater method overestimated total intake in grams and energy in kilocalories in minority preschool children in a well-controlled condition and needs to be further tested in a free-living environment.
    背景与目标:
  • 【教学本科生进行根管治疗的方法: 它对根充填质量的影响。】 复制标题 收藏 收藏
    DOI:10.1111/eje.12275 复制DOI
    作者列表:Baaij A,Özok AR
    BACKGROUND & AIMS: INTRODUCTION:This study aimed to assess whether the method of teaching endodontology influenced the quality of root fillings made by undergraduate students. MATERIALS AND METHODS:The method of teaching endodontology at our institution was revised. Changes concerned: the programme (ie method of clinical training and summative assessment), and the supervision whilst performing root canal treatment on patients. An intermediate cohort (N=91) comprised partly students attending the former programme (involving patients) and partly students attending the revised programme (without patients). After succeeding in the summative assessment, the quality of the first root filling made by the student in a patient under supervision of either a general dental practitioner or an endodontist was evaluated according to pre-determined criteria. Data were analysed using Cohen's Kappa, Chi-square, Fisher's exact, Mann-Whitney and Kruskal-Wallis tests. RESULTS:Sixty-two per cent (47 of 76) of root fillings made by students who attended the revised programme were of good quality, in comparison with 47% (seven of 15) of those made by students who attended the former programme (P=.274). Less complex treatments had better quality root fillings if students were supervised by endodontists (88% (14 of 16) good quality) than supervised by general dental practitioners (59% (22 of 37) good quality) (P=.045). Complex treatments did not differ in quality of root fillings for the supervision types (P=.825). CONCLUSION:The quality of root fillings made by students who attended the revised programme seems at least as high as that of those who attended the former programme. Higher quality root fillings might be obtained under supervision of endodontists than under supervision of general dental practitioners.
    背景与目标:

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