Lipoprotein (a) Cut-Off in Chronic Kidney Disease Patients with a History of Cardiovascular Disease in Center Hospital University Souro SANOU, Burkina Faso

Patients living with chronic kidney disease (CKD) are at high risk of cardiovascular events. Our aim in this study was to assess the cut-off value for lipoprotein (a) (Lp(a)) in CKD patients with a history of cardiovascular disease (CVD). This was a cross-sectional study. Variables including age, sex, history of CVD, body mass index and CKD stage, were collected during CKD patient’s first admission in the nephrology dialysis department. Blood samples were collected for quantitative determination of Lp(a) by immunoturbidimetric method. They were divided into two groups: CKD patients without history of CVD and CKD patients with history of CVD. Fisher’s exact test was used to assess associations with a significance level of 0.05%. Area under the curve (AUC) and new cut-off value for Lp(a) were identified by drawing Receiver Operating Characteristic (ROC) curve. A total of seventy CKD patients with median age of 43 years [minimum-maximum = 15 - 78 years] were included. Patients with history of CVD were 65.71% (46/70). New Lp(a) cut-off point in CKD patients with history of CVD was 66.50 nmol/L [sensitivity, 87.00%;specificity, 58.30%;AUC = 0.727;p = 0.000]. ROC curve demonstrated good performance of Lp(a) to screen CKD patients with history of CVD. Further research is needed to determine an LPA gene polymorphism’s contribution to increasing risk for CVD at each kidney disease stage.

基于cut-off方法刚性承台下群桩基础优化分析

针对刚性筏板下群桩基础优化设计问题进行分析,通过改变桩长分布来调整各桩的荷载分担,群桩分析采用基于弹性理论的积分方程方法,并通过cut-off方法来反映桩的弹塑性特性,实现群桩基础的弹塑性优化分析,改进了常规弹性分析方法的缺陷。算例分析表明,随着外荷载的不断增加,角桩首先达到极限荷载,对角桩超出极限荷载的部分进行重新分布,继而使得边桩逐渐达到极限承载状态,继续加载直至内桩也达到极限承载状态,从而引起桩筏基础的整体破坏。采用cut-off方法可以改进基础变刚度优化设计,使之与实际情况更为吻合。

利用RIBA试验确定HCV抗体检测的cut-off值及比较分析

目的利用重组蛋白免疫印迹分析(RIBA)实验,制定本实验室所用的日本希森美康公司的HISCL-5000型化学发光免疫分析仪及配套的相关试剂检测丙型肝炎病毒抗体(抗-HCV)的cut-off值。方法在2015年10月至2016年9月所检测的19341例患者标本中收集抗-HCV阳性标本80例,进行RIBA确认实验后进行分析,再利用ROC曲线计算出cut-off值。结果在本室HCV抗体阳性率为0.41%的数据中,RIBA结果可分为3种,其中25例(31.3%)为阴性,18例(22.5%)为不确定,37例(46.2%)为阳性。当截断值为3.95 COI时,灵敏度为81.1%,特异性为95.1%。另外当特异性为100%时,截断值为5.25 COI,灵敏度为73%。结论希森美康HISCL-5000型化学发光免疫分析仪及配套的相关试剂检测丙型肝炎病毒抗体(抗-HCV)与RIBA结果间呈正相关;当cut-off值为3.95 COI时,是一个适合本实验室的cut-off值。

六种国产乙型肝炎表面抗体ELISA试剂盒符合率及cut-off值探讨

探讨了六种国产乙型肝炎表面抗体(HBsAb)酶联免疫吸附法(ELISA)试剂盒的符合率、试剂盒临界(cut-off)值的合适性以及采用cut-off血清的可行性。分别用电化学发光法(ECLIA)和六种国产ELISA试剂检测HBsAb标准物质和收集的临床标本。以试剂盒cut-off值判定结果,仅试剂E和F检测10 mIU/ml的HBsAb标准物质阳性率为100%。试剂C、E的精密度最高。以10 mIU/ml HBsAb标准物质作为cut-off血清,六家试剂的cut-off值和灰区范围差别较大,试剂D的cut-off值最低,灰区范围最小,试剂F的cut-off值最高,灰区范围最大。当临床标本HBsAb浓度<10 mIU/m、10~<50 mIU/m、50~<100 mIU/ml时,大多数试剂厂家试剂用试剂盒cut-off值判定结果的阳性符合率与cut-off血清存在差异。HBsAb浓度100~1000 mIU/ml临床标本,六种试剂用两种cut-off值判定结果阳性符合率均为100%。六家国产HBsAb ELISA试剂盒检测性能存在一定差异,试剂盒推荐的cut-off值计算方式存在不足,采用cut-off血清会改变试剂盒的阴性和阳性符合率,使用前需使用临床标本充分验证。

应用GSP筛查新生儿G6PDd的性能验证及cut-off值设定

目的对全自动荧光免疫分析仪(GSP)检测干血片葡萄糖-6-磷酸脱氢酶(G6PD)的性能进行验证,并初步建立该方法筛查葡萄糖-6-磷酸脱氢酶缺乏症(G6PDd)的cut-off值。方法前期确定验证方案,对试剂盒自带标准品B、D、E 3个浓度的标本,L、H两个浓度的质控品及试剂盒自带标准品B、C、D、E、F 5个浓度标本进行GSP系统的精密度、正确度和线性范围的验证。采用GSP和目前临床常规使用的Victor2D 1420型荧光免疫分析仪(半自动荧光免疫分析仪)同步检测2742例新生儿干血片G6PD水平,比较两种仪器结果,并使用百分位数分布及受试者工作特征(ROC)曲线初步建立中山市博爱医院产前诊断中心GSP筛查G6PDd时G6PD水平的cut-off值。结果应用GSP检测G6PD时,批内变异系数分别为2.09%、1.54%和1.90%,总变异系数分别为3.08%、1.72%和2.12%,分别小于厂家声明的3.40%和3.90%;质控浓度L的25份标本的测量总均值与靶值的相对偏差为3.84%,质控浓度H的25份标本的测量总均值与靶值的相对偏差为3.44%;5个浓度标本的检测值和理论值的线性回归方程为Y=1.0082 X+0.0125,决定系数(R^(2))为0.9991,R^(2)>0.995,线性相关性良好。标本总体P_(5)的G6PD水平为20.10 U/dL。两种仪器的一致性良好。结论GSP应用于中山市新生儿G6PD检测中,精密度、准确度、线性范围均达到了厂家声明的检测性能,可常规用于新生儿G6PDd筛查。该中心初步采用的GSP新生儿G6PDd筛查的cut-off值为20.10 U/dL。

Numerical stress-deformation analysis of cut-off wall in clay-core rockfill dam on thick overburden

The cut-off wall in a clay-core rockfill dam built on a thick overburden layer is subjected to a large compressive pressure under the action of the loads such as the dead weight of both the dam and the overburden layer, the frictional force induced by the differential settlement between the cut-off wall and surrounding soils, and the water pressure. Thus, reduction of the stress of the cut-off wall has become one of the main problems for consideration in engineering design. In this paper, numerical analysis of a core rockfill dam built on a thick overburden layer was conducted and some factors influencing the stress-strain behaviors of the cut-off wall were investigated. The factors include the improvement of the overburden layer, the modeling approach for interfacial contact between the cut-off wall and surrounding soils, the modulus of the cut-off wall concrete, and the connected pattern between the cut-off wall and the clay core. The result shows that improving the overburden layer,selecting plastic concrete with a low modulus and high strength, and optimizing the connection between the cut-off wall and the clay core of the dam are effective measures of reducing the deformations and compressive stresses of the cut-off wall. In addition, both the Goodman element and the mud-layer element are suitable for simulating the interfacial contact between the cut-off wall and surrounding soils.

A case study of a Kuroshio main path cut-off event and impacts on the South China Sea in fall-winter 2013–2014

This study examines a Kuroshio main path(KMP) cut-off event east of Taiwan Island occurred in fall-winter2013–2014 and its impacts on the South China Sea(SCS) by analyzing satellite altimetry and mooring observations. Satellite altimeter sea level anomaly(SLA) images reveal a complete process that a huge cyclonic eddy(CE) from the Pacific collided with the Kuroshio and the western boundary from 15 October 2013 to 15 January 2014. Mooring observations evidenced that the Kuroshio upper ocean volume transport was cut off more than 82% from 17×106 m^3/s in September to 3×106 m^3/s in November 2013. The KMP cut-off event caused the Kuroshio branching and intruding into the SCS and strengthened the eddy kinetic energy in the northern SCS west of the Luzon Strait. Using the total momentum as a dynamic criterion to determine the role of eddy collision with the Kuroshio reasonably explains the KMP cut-off event.

柳州地区早产儿先天性肾上腺皮质增生症筛查实验cut-off值初探

目的确立柳州地区17-羟孕酮(17-OHP)对早产儿先天性肾上腺皮质增生症筛查的cut-off值。方法新生儿出生72h后采集足跟血,滴于规定滤纸上,采用时间分辨荧光免疫分析法检测17-OHP浓度。结果收集1 721例早产儿,正常体质量(≥2 500g)早产儿749例,17-OHP浓度的95%、99%分位数值分别为26.4nmol/L、38.1nmol/L;低体质量(<2 500g)早产儿为972例,17-OHP浓度的95%、99%分位数值分别为37.7nmol/L、67.0nmol/L。低体质量早产儿17-OHP浓度与正常体质量早产儿比较,差异有统计学意义(P<0.01)。正常体质量早产儿17-OHP浓度cut-off值为30.0nmol/L,低体质量早产儿的17-OHP浓度cut-off值为40.0nmol/L。结论早产儿17-OHP cut-off值确定,对先天性肾上腺皮质增生症筛查具有临床意义。

Dynamic monitoring of menopause hormone therapy and defining the cut-off value of endometrial thickness during uterine bleeding

The aim of this study was to evaluate the effects of low-dose tibolone therapy on ovarian area, uterine volume and endometrial thickness, and define the cut-off value of endometrial thickness for curettage during uterine bleeding. We followed 619 postmenopausal women, aged 40-60 years, for two years. There were 301 subjects in the low-dose tibolone treatment group and 318 subjects in the control group. The ovarian area, uterine volume and endometrial thickness in all participants were measured by transvaginal ultrasound prior to, one and two years post enrollment, respectively. Endometrial specimens were collected from all subjects with abnormal uterine bleeding during the follow-up period. We found that the uterine volume in the treatment group was greater than that in the control group, and the difference was significant （P〈0.05）, but there were no significant differences in ovarian area and endometrial thickness between the two groups （P〉0.05）. When the cut-off value for endometrial thickness was 7.35 ram, the sensitivity and specificity were 100% and 79.07%, respectively, and 85.71% and 93.02% when 7.55 mm was set as the cut-offduring tibolone therapy. The results indicate that low-dose tibolone therapy may postpone uterine atrophy and the cut-off value of endometrial thickness may be appropriately adjusted for curettage.

The Impact of Cut-off Lows on Ozone in the Upper Troposphere and Lower Stratosphere over Changchun from Ozonesonde Observations

In situ measurements of the vertical structure of ozone were made in Changchun （43.53°N, 125.13°E）, China, by the Institute of Atmosphere Physics, in the summers of 2010-13. Analysis of the 89 validated ozone profiles shows the vari- ation of ozone concentration in the upper troposphere and lower stratosphere （UTLS） caused by cut-off lows （COLs） over Changchun. During the COL events, an increase of the ozone concentration and a lower height of the tropopause are observed. Backward simulations with a trajectory model show that the ozone-rich airmass brought by the COL is from Siberia. A case study proves that stratosphere-troposphere exchange （STE） occurs in the COL. The ozone-rich air mass transported from the stratosphere to the troposphere first becomes unstable, then loses its high ozone concentration. This process usually happens during the decay stage of COLs. In order to understand the influence of COLs on the ozone in the UTLS, statistical analysis of the ozone profiles within COLs, and other profiles, are employed. The results indicate that the ozone concentrations of the in-COL profiles are significantly higher than those of the other profiles between ±4 km around the tropopause. The COLs induce an increase in UTLS column ozone by 32% on average. Meanwhile, the COLs depress the lapse-rate tropopause （LRT）/dynamical tropopause height by 1.4/1.7 km and cause the atmosphere above the tropopause to be less stable. The influence of COLs is durable because the increased ozone concentration lasts at least one day after the COL has passed over Changchun. Furthermore, the relative coefficient between LRT height and lower stratosphere （LS） column ozone is -0.62, which implies a positive correlation between COL strength and LS ozone concentration.

Collector optimization for tradeoff between breakdown voltage and cut-off frequency in SiGe HBT

As is well known, there exists a tradeoff between the breakdown voltage BVcEO and the cut-off frequency fT for a standard heterojunction bipolar transistor （HBT）. In this paper, this tradeoff is alleviated by collector doping engineering in the SiGe HBT by utilizing a novel composite of P＋ and N- doping layers inside the collector-base （CB） space-charge region （SCR）. Compared with the single N-type collector, the introduction of the thin P＋ layers provides a reverse electric field weakening the electric field near the CB metallurgical junction without changing the field direction, and the thin N layer further effectively lowers the electric field near the CB metallurgical junction. As a result, the electron temperature near the CB metallurgical junction is lowered, consequently suppressing the impact ionization, thus BVcEO is improved with a slight degradation in fT. The results show that the product of fTXBVcEo is improved from 309.51 GHz.V to 326.35 GHz.V.

Suppressing the weakly bound states in the photoassociation dynamics by using a frequency cut-off laser pulse

The photoassociation dynamics of ultracold lithium atoms controlled by a cut-off pulse has been investigated theoretically by solving numerically the time-dependent Schr6dinger equation using the mapped Fourier grid method. The frequency components of the laser pulse close to the atomic resonance are partly cut off. Compared with the typical Gauss-type pulses, the cut-off pulse is helpful to suppress efficiently the weakly bound states and prepare the associated molecules in the lower vibrational states. Especially, the dependence of photoassociation probability on the cut-off position of the laser pulse is explored.

Effect of Cut-Off Frequency of Butterworth Filter on Detectability and Contrast of Hot and Cold Regions in Tc-99m SPECT

In SPECT, noise is one of the major limitations that degrade image quality. To suppress the noisy signals in an image, digital filters are most commonly applied. However, in SPECT image reconstruction, selection of an appropriate filter and its functions has always remained a difficult task. In this work an attempt was made to investigate the effects of varying cut-off frequencies and in keeping the order of Butterworth filter constant on detectability and contrast of hot and cold re-gions images. A new insert simulating hot and cold regions which provides similar views in a reconstructed image was placed in the phantom’s cylindrical source tank and imaged. Tc-99m radionuclide was distributed uniformly in the phantom. SPECT data were collected in a 20% energy window centered at 140 keV by a Philips ADAC Forte dual head gamma camera mounted with a LEHR collimator. Images were generated by using the filtered backprojection technique. A Butterworth filter of order 5 with cut-off frequencies 0.35 and 0.45 cycles·cm-1 was applied. Images were examined in terms of hot and cold regions, detectability and contrast. Results show that the hot and cold regions’ detectability and contrast vary with the change of cut-off frequency. With a 0.45 cycles·cm-1 cut-off frequency, a significant enhancement in contrast of cold regions was achieved as compared to a 0.35 cycles·cm-1 cut-off frequency. Furthermore, the detectability of hot and cold regions improved with the use of a 0.45 cycles·cm-1 cut-off frequency. In conclusion, image quality of hot and cold regions affected in a different way with a change of cut-off frequency. Thus, care should be taken in selecting the filter cut-off frequency prior to reconstruction of images;particularly, when both types of regions are expected in the reconstructed image.

OPTIMIZATION OF CUT-OFF GRADE IN OPEN-PIT BASED ON CONTROL THEORY

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THE NUMERICAL SOLUTIONS OF CUT-OFF FREQUENCIES IN TWO-DIELECTRIC LAYERED WAVEGUIDE BY USING BOUNDARY ELEMENT METHOD

This paper diseusses the general principle of finding the cut-off frequencies in two-dielectric lay-ered waveguides by using the boundary element method,based on the fundamental solution of a twodimensional Helmholtz equation.In terms of the formulae given in the paper,some numerical resultsare obtained for two commonly used configurations.The fimal results show that the method is of an appre-ciable precision.

Determination of the Optimal Waist Circumference Cut-Off Points in Benin Adults

Obesity is an independent risk factor for chronic diseases such as diabetes, cardiovascular diseases and certain cancers. Early detection of abdominal obesity followed by appropriate interventions will prevent associated diseases. The objective was to determine optimal waist circumference (WC) cut-off points predictive of at least one other component of metabolic syndrome in Benin adults. This longitudinal and observational study included at the baseline 541 apparently healthy subjects aged 25 - 60 years randomly selected in the largest city of Cotonou (n = 200), the smaller-size city of Ouidah (n = 171) and rural surroundings of Ouidah (n = 170) in Benin. Components of the metabolic syndrome considered along with abdominal obesity were high blood pressure, high fasting glycaemia, low HDL-cholesterol and high triglycerides as defined by the Joint Interim Statement. After the baseline survey, the subjects were followed-up for four years. Complete data at baseline and four years later were available in 416 subjects. The receiver operating characteristic (ROC) curve for waist circumference to predict at least one other component of the metabolic syndrome was plotted and the Youden index was used to define the optimal cut-offs of WC. At the baseline of the study, the optimal WC cut-off point to predict the presence of at least one other component of the metabolic syndrome was 80 cm for men (sensitivity = 0.62, specificity = 0.65);the area under the ROC curve was 0.67 (IC 95%: 0.61-0.74). In women, the optimal WC cut-off point was 90 cm (sensitivity = 0.54, specificity = 0.80), and the area under the ROC curve was 0.68 (IC 95%: 0.62-0.75). These optimal cut-offs were similar four years later. Optimum WC cut-off points for both men and women in Benin differ from those currently recommended for sub-Saharan Africans. Therefore, waist circumference cut-off points for abdominal obesity need to be reconsidered for these populations.

An Experimental Method to Determine the Cut-Off Frequency of an Acoustical Free Field in a Non-Ideal Environment

The availability of ideal conditions like anechoic chamber to characterize some sound parameters, like sound intensity and sound power necessities the determination of free field and cut off frequency measurements. In this article, full experiment was executed at Wayne State University (Detroit-Michigan), to determine the cut off frequency in all directions;the obtained results showed that the free field can be determined for a specified space. So other tests can take place in this space avoiding regions where reflections and consequently noise can be found. Upon these results tests related to noise abatement in vehicles can be done in such environment.

Determination of a Cut-Off Point of a Scale for Achievement Motive in Geriatrics That Predicts the Frequency of Undertaking Instrumental Activities of Daily Living in Community-Dwelling Elderly People

Background: Among elderly people, rehabilitation is important for reducing the risk of falls and hospitalization and to maintain an independent life for longer. Motivation is a factor for elderly people to lead an active daily life and leave home more frequently. Purpose: The purposes of this study were to determine the optimal cut-off point in the Scale for Achievement Motive in Geriatrics (SAMG) that could identify individuals as inactive or active, based on the Frenchay Activities Index (FAI), and to compare characteristics between active and inactive groups classified by the cut-off point. Methods: A cross-sectional study of 285 community-dwelling elderly people measured SAMG and FAI and physical function. Receiver operating characteristic (ROC) analysis was used to calculate the area under the curve (AUC) that was the optimal cut-off point for the SAMG total score, with the associated sensitivity and 1-specificity when compared with the FAI results. Demographic parameters and physical function were compared between two groups defined by cut-off point. Results: The AUC was 0.78, the optimal cut-off for SAMG total score for indicating inactivity was ≤48, the sensitivity was 77.98% and the 1-specificity was 75.00%. The group with SAMG score >48 was characterized by a significantly higher proportion of women, fewer people sharing a house, and participation in more hobbies. Discussion: A cut-off point of 48 in the SAMG could be a predictive index of motivation toward goals for individuals with inactive daily activities. The group with score higher than the cut-off was characterized by more women, fewer people living together, and more hobbies than the group with lower scores.

Evanescent Fields inside a Cut-off Waveguide as Near Fields

Usually, electromagnetic evanescent waves are some kinds of near fields. However, it looks as if the evanescent waves inside a cut-off waveguide had nothing to do with any near field. In this paper, we will show that the evanescent waves inside a cut-off waveguide can also be regarded as the near fields of an aerial array.

45°倾斜应用的多通道干涉截止滤光片研制

光纤通信的发展对通信器件中薄膜滤光片提出了新的要求。根据45°倾斜应用的多通道干涉截止滤光片的设计指标,选择Nb2O5和SiO2为高、低折射率材料设计非规整膜系,以减少偏振效应的影响。结合APS1104型镀膜机的特点,分析了设计膜系的膜层灵敏度和薄膜生长过程中的模拟监控曲线,判断设计薄膜的可镀制性。然后采取直接光学监控方式,选择合适的镀制工艺成功镀制滤光片。测试结果表明:滤光片在45°倾斜应用条件下,1255~1365 nm、1475~1502 nm双通带最大插入损耗为0.199 dB,1547~1565 nm为反射带,通带隔离度为17.3 dB,满足系统应用需求。