Determination of urinary 8-hydroxy-2′-deoxyguanosine by capillary electrophoresis with molecularly imprinted monolith in-tube solid phase microextraction

Urinary 8-hydroxy-2 -deoxyguanosine(8-OHdG) is an excellent marker of oxidative DNA damage.In this study,employing guanosine as dummy template a novel molecularly imprinted(MIP) monolithic capillary column had been synthesized,and that was used as medium of in-tube solid phase microextraction(SPME).Coupled with capillary electrophoresis-electrochemical detection(CE-ECD),the system of extraction and detection of 8-OHdG in urinary sample had been developed.Because of its greater phase ratio combined with conv...

QFT-GIT对儿童肺结核临床诊断价值的meta分析

目的系统评价QFT-GIT对儿童肺结核临床诊断价值。方法计算机检索中国生物医学数据库、中国知网(CNKI)全文数据库、维普数据库、万方全文数据库、EMBASE,PUBMED和Cochrane并提取数据,应用Stata软件进行meta分析。结果分析纳入的5个研究。结果显示,QFT-GIT作为儿童肺结核诊断试验,灵敏度点估计值为0.76,95%CI=0.65～0.84,特异度点估计值为0.98,95%CI=0.91～1.00。另外,阳性似然比点估计值为42.0,95%CI=8.5～207.8,阴性似然比点估计值为0.25,95%CI=0.17～0.37,诊断优势比OR=169,95%CI=37～775。结论 QFT-GIT具有排除诊断的能力,但鉴于受试儿童免疫状态和感染风险的差异会造成其检测能力表现存在差异,建议对该方法进行进一步评价。

长管呼吸器应用于深水导管架施工安全管理

在国家和海洋石油行业“深水战略”背景下,海洋石油行业得到了蓬勃发展,深水海洋石油平台项目不断增多。导管架平台作为应用最广泛的固定式平台,相比于浅水导管架,建造阶段难度更大、风险较高。文章聚焦于建造阶段安全管理,重点分析管腿内受限空间施工作业风险,以及常规通风方式的特点和存在的不足之处。并重点阐述了长管呼吸器替代常规通风模式的工作原理、实际应用效果、应急管理拓展应用及可推广性,以期更好地控制安全风险,保证作业人员安全。

Performance and correlation of QuantiFERON-TB Gold, T-SPOT.TB and tuberculin skin test in young children with or exposed to tuberculosis

Objective:To evaluate the performance of interferon gamma release assays and tuberculin skin test in Bacillus Calmette-Guerin vaccinated young children.Methods:A cross-sectional study was conducted in healthy children younger than 5 years who were recently diagnosed with tuberculosis or had recent exposure to active tuberculosis.QuantiFERON-TB Gold,T-SPOT.TB and tuberculin skin test were performed in each patient.Results:Of the 60 children,median age 3.3 years,17 had tuberculosis and 43 had recent tuberculosis exposure.Overall,15(25.0%)children had tuberculin skin test reaction≥10 mm;8(13.3%)were positive by QuantiFERON-TB Gold In-Tube test,and 12(20.0%)by T-SPOT.TB.Nineteen(31.7%)children had at least one positive test.There was a moderate agreement between interferon gamma release assays and tuberculin skin test.Conclusions:The positive rates of interferon gamma release assays and tuberculin skin test were low in young children who were infected with tuberculosis,supporting the management strategy of not testing children younger than 5 years.

Concrete-Filled Steel Tube Arch Bridges in China

In the past 20 years, great progress has been achieved in China in the construction of concrete-filled steel tube （CFST） arch bridges and concrete arch bridges with a CFST skeleton. The span of these bridges has been increasing rapidly, which is rare in the history of bridge development. The large-scale construction of expressways and high-speed railways demands the development of long-span arch bridges, and advances in design and construction techniques have made it possible to construct such bridges. In the present study, the current status, development, and major innovative technologies of CFST arch bridges and concrete arch bridges with a CFST skeleton in China are elaborated. This paper covers the key con- struction technologies of CFST arch bridges, such as the design, manufacture, and installation of steel tube arch trusses, the preparation and pouring of in-tube concrete, and the construction of the world＇s longest CFST arch bridge-the First Hejiang Yangtze River Bridge. The main construction technologies of rein- forced concrete arch bridges are also presented, which include cable-stayed fastening-hanging cantilever assembly, adjusting the load by means of stay cables, surrounding the concrete for arch rib pouring, and so forth. In addition, the construction of two CFST skeleton concrete arch bridges-the Guangxi Yongning Yong River Bridge and the Yunnan-Guangxi Railway Nanpan River Bridge--is discussed. CFST arch bridges in China have already gained a world-leading position; with the continuous innovation of key technologies, China will become the new leader in promoting the development of arch bridges.

结核菌素试验阳性的接触者随访期间γ-干扰素释放试验的研究

背景:在进行大规模接触者调查后,对结核菌素试验(TST)阳性个体提供预防性抗结核治疗。目的:研究随访期间异烟肼(INH)的治疗效果和γ-干扰素释放试验(IGRA)的时效。设计:在大规模接触者调查期间,TST检测为阳性的对象(n=122例)纳入本研究。在2年里,每6个月抽取一次血标本用来进行两种试验。结果:122例中,36例(29.5%)完成异烟肼预防性治疗,71例(58.2%)每6个月进行一次X线筛查随访,另有15例(12.3%)未完成异烟肼预防性治疗。阳性者的总百分率在2年间保持稳定,大约在45%～50%,但随着时间的推移,个体的反应有变化。大多数初始IGRA低者,随访期间其结果仍然在临界值以下,初始IGRA结果高的仍为阳性,而IGRA初始结果为中等程度者,随访期间有多种动态类型。结论:本研究显示IGRA反应随着时间推移变异较大,提示其在潜伏感染个体随访中的应用价值有限。然而,在那些初始IGRA为中等程度结果的个体表现出不同动态类型的意义,需要进一步研究。

螺旋弹簧管的成型工艺研究

螺旋弹簧管是一种使用广泛的传感器零件,其形状对测量精度影响颇大,使用传统的工艺加工该零件时,通常需要额外的工序对焊接端修整。文中修正了基本螺旋线方程,提出了一种新的加工工艺,通过倾斜螺旋线中轴线,倾斜螺旋成圈机构,直接达到使零件的固定端和自由端分别所在的平面平行的目的,不需要二次加工。此方法对螺旋线类零件的加工具有一定的参考意义,可简化工序提高生产效率。

Study of A1298C MTHFR Gene Polymorphism as a Risk Factor for Neural Tube Defects in the Eastern Algerian Population

Background: As C677T mutation, A1298C mutation in methylene tetrahydrofolate reductase (MTHFR) gene results in a decreased MTHFR activity but to a less extent, it is known as a risk factor of predisposition to human neural tube defects (NTDs), in some populations. Our objective was therefore to study, for the first time in Algerian population, if A1298C polymorphism confers risk for the occurrence of this abnormality. We have examined the distribution of the genotype and the allele frequencies of A1298C mutation, and also their influence on plasma homocysteine (Hcy) concentration. Patients and Methods: We studied this polymorphism in 38 mothers of NTD cases and 67 control individuals of an eastern Algerian population. The mutation was determined by polymerase chain reaction-restriction fragment length polymorphism analysis (PCR/RFLP). Plasma homocysteine concentration was analyzed using an automated chemiluminescence method. Results: No signi?cant association could be observed between allele and genotypes frequencies of A1298C MTHFR gene polymorphism and NTDs risk. However, we could observe that A1298C polymorphism affects homocysteine metabolism in mothers of NTD cases leading to homocysteine concentration values higher in AA genotype and lower in AC/CC genotypes (15.29 ± 11.8 μmol/l vs. 8.63 ± 3.83 μmol/l, p < 0.05). Conclusion: Data indicate that A1298C MTHFR gene polymorphism might be a risk factor by affecting homocysteine metabolism in mothers of Algerian children with NTDs.

Inositol (1,4,5)-triphosphate Modulates Pollen Tube Polar Growth

In this article, the functions of D-myo-inositol-1,4,5-trisphosphate (Ins [1,4,5] P3) in regulating pollen tube polar growth were investigated by application of caged version of the phosphoinositides. To increase the intracellular Ins（1,4,5）P3 concentration at the apical region of pollen tube, the caged Ins（1,4,5）P3 loaded by osmotic shock was activated by 10 s 360 nm UV flash at this domain （10 μm from the tip）. More than 70% pollen tubes were induced swelling at apex and/or growth axis reorientation, accompanying temporarily growth arrest, by localized increase of Ins（1,4,5）P3 concentration （n=21）. While, pollen tubes without being loaded with caged Ins（1,4,5）P3 had not response to the same dosage UV flash. With FM 1-43 fluorescent staining, it was found that growth perturbation by UV activated caged Ins（1,4,5）P3 had tight link with membrane trafficking at the apical zone of pollen tubes. Upon UV pulse, the apical V-shaped bright area where was full of secretory vesicles spread to a much broader region, which implied that actin filaments at the apical region were remodeled. It was also observed that the FM 1-43 fluorescence intensity at tip remarkably increased than that before UV flash, which demonstrated that more secretory vesicles were accumulated at this region. To estimate the role of Ins（1,4,5）P3 in modulating intracellular calcium concentration and distribution, dextran conjugated fluorescent dye Calcium Green-1 and Rhodamine B were microinjected into pollen tubes together with caged Ins（1,4,5）P3. The results showed that calcium concentration at the subapical region increased upon UV released Ins（1,4,5）P3. Consequently, the tip-focused calcium gradient under the apical dome of pollen tube was disturbed. Simultaneously, the pollen tube bulged at the apical region and its growth rate decreased. As the tip-focused calcium gradient was reestablished, the pollen tube morphology and growth recovered to the normal level. Therefore, Ins（1,4,5）P3 can modulate pollen tube growth rate and direction through mobilizing intracellular calcium and regulating vesicle trafficking during pollen tube finding its way to the ovary.

Study on Characteristics of Steady Flow Condensation Heat Transfer in a Tube under Zero－Gravitation

In this paper, the annular flow. model for in tube completed condensation is employed to predict the steady flow condensation heat transfer characteristics in a tube under zero-gravitation. In this easel it is proposed that vapor condenses on the liquid film surface. Due to the effect of surface tension, the liquid exists in the form of liquid film ring contacting wall; when the velocity of vapor core decreases to zerol the condensation process ends. Putting forward the physical and mathematical models, the problem is solved and the multi-order equation of the thickness of liquid film is obtained, which includes terms of the pressure gradient along axial direction, the friction force between vapor and liquid on interface. By computational calculation, this model can be used not only to predict the thickness of liquid film, the condensation pressure gradient along the axial direction, but also to determine the Nusselt number, the condensation length and the total flow pressure drop of condensation etc. At the end, the calculation results of the necessary condensation length are compared approximately with those from the experiments, which are obtained on the test set-up placed horizontally in gravitation field, and the deviation is analyzed.

Influence of Tube's Diameter on Boiling Heat TransferPerformance in Small Diameter Tubes

This paper reports the experiments of evaporation study in 6 mm inner copper diamter tubes us-ing HFC-134a, HCFC-22 and CFC-12 as working nuid. The results show that the evaporation heat transfer coefficient increases with the decreasing of inner diameter of tubes. A new concept of non-dimensional tube diameter U is proposed in this paper for correction of the influence of the tube diameter on the evaporation heat transfer coefficient. And further, a convnient empirical correction mehod is pented.

An Experimental Study of Condensation Heat Transfer in Sub-Millimeter Rectangular Tubes

The characteristics of local heat transfer and pressure drops were experimentally investigated using condensing R134a two-phase flow, in single rectangular tubes, with hydraulic diameter of 0.494, 0.658, and 0.972 mm. New experimental techniques were used to measure the in-tube condensation heat transfer coefficient especially for the low heat and mass flows. Tests were performed for a mass flux of 100, 200, 400, and 600 kg/m2s, a heat flux of 5 to 20 kW/m2, and a saturation temperature of 40℃. In this study, effect of heat flux, mass flux, vapor qualities, and hydraulic diameter on flow condensation were investigated and the experimental local condensation heat transfer coefficients and frictional pressure drop are shown. The experimental data of condensation Nusselt number are compared with previous correlations, most of which are proposed for the condensation of pure refrigerant in a relatively large inner diameter round tubes.