Seroprevalence of SARS-CoV-2 in Croatian solid-organ transplant recipients

IntroductionThe data on the coronavirus disease (COVID-19) in solid-organ transplant recipients (SOTRs) in Croatia is unknown. The aim of this study was to analyze the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Croatian SOTRs.Materials and methodsFrom 7 September to 27 November 2020 (beginning of the second COVID-19 pandemic wave), a cross-sectional screening for COVID-19 was performed in the adult outpatient liver (LTRs; N = 280) and kidney transplant recipients (KTRs; N = 232). Serum samples were initially tested for SARS-CoV-2 IgG antibodies using a commercial enzyme-linked immunosorbent assay (ELISA; Vircell Microbiologists, Granada, Spain). All positive samples were confirmed using a virus neutralization test (VNT). Data on risk exposure and COVID-19 related symptoms were collected using a questionnaire.ResultsThe transplanted cohort’s seroprevalence detected by ELISA and VNT was 20.1% and 3.1%, respectively. Neutralizing (NT) antibodies developed in 15.6% of anti-SARS-CoV-2 ELISA IgG positive SOTRs. The difference in seropositivity rates between LTRs and KTRs was not statistically significant (ELISA 21.1% vs. 19.0%, P = 0.554; VNT 3.6% vs. 2.6%, P = 0.082). Overall VNT positivity rates were higher in patients who reported participation in large community events (5.9% vs. 1.0%; P = 0.027) as well as in patients who reported COVID-19 related symptoms in the past six months. In addition, symptomatic VNT positive patients showed significantly higher (P = 0.031) NT antibody titers (median 128, interquartile range (IQR) = 32-128) compared to asymptomatic patients (median 16, IQR = 16-48).ConclusionsThis study showed that 15.6% of anti-SARS-CoV-2 ELISA positive Croatian SOTRs developed NT antibodies indicating protective immunity. Further studies are needed to determine the dynamic of NT antibodies and COVID-19 immunity duration in immunocompromised populations such as LTRs and KTRs.     

A sensitive and economical modified method for estimation of cerebrospinal fluid proteins

Cerebrospinal fluid protein estimation is a routine diagnostic tool for various diseases. The proposed modified bromocresol green (BCG) method is applicable to automated as well as manual measurements. Protein concentrations and absorbance at 600 nm are linearly related throughout a wide range of concentrations from 10 mg % to 2000 mg %. Ninety C.S.F. samples were analyzed and results obtained by both the modified BCG method and routine pyrogallol red method were compared. An excellent co-relation was observed (n=90, g=0.996, P<0.001).     

Modification of thyroid stimulating hormone estimation method in alpha prime LS system (SFRI)

The alpha prime LS (APLS) system consists of both enzyme linked immunosorbant assay (ELISA) and chemiluminescence immunoassay (CLIA) processing arrangements. All the programmes are open and accessible to modification. But, as CLIA kits are system dedicated kits, so the option for user defined programme may only be utilized for modification as and when it is absolutely necessary. The author had, some problem during routine performances with thyroid stimulating hormone (TSH) Monobind, U.S.A, kits. So, the author modified the incubation temperature, time of decontamination, use of signal reagents and finally the calibration pattern.     

Development of a rapid and inexpensive plasma glucose estimation by two-point kinetic method based on glucose oxidase-peroxidase enzymes

A rapid and inexpensive plasma glucose estimation by two-point kinetic method based on glucose oxidase and peroxidase enzymes has been developed it takes only 11/2 minutes of time and validity of the method has been discussed.     

Standardization of a colorimetric method for the determination of fructose using o-cresol: Sulphuric acid reagent

Fructose developed a pinkish orange chromogen on treatment with o-cresol: 70% sulphuric acid at 32°C for 15 minutes with a λ max of 500nm. Fructose was 185 times more chromogenic than glucose. Total carbohydrate and fructose values in protein-free filtrate of normal serum samples were in the range, 55.4–86.3 mg/dl and 1.55–3.29 mg/dl, respectively. In diabetes, the observed values were 197–354 mg/dl and 2.91–6.81 mg/dl, respectively.     

六维球面中的SU(2)-轨道(英文)

利用标准的SU(2)不可约酉表示,构造了SU(2)到G2的实不可约表示.同时,研究了S6中不同的SU(2)-轨道类型,特别是3维CR-轨道.     

Levels of plasma soluble complement receptor 1 (sCR1) in normal Indian adult population

A decrease in the membrane anchored erythrocyte complement receptor 1 (CR1) is reported as an acquired phenomenon in a number of inflammatory and autoimmune diseases with concomitant rise in soluble CR1 (sCR1) levels in plasma. There is a need to establish the normal range of sCR1 in Indian adults to assess the function and disease association of this protein. The plasma sCR1 levels of 50 healthy individuals have been estimated by an indigenously developed sandwich ELISA. sCR1 levels from 26 patients suffering from nephropathies had also been assayed which was much higher than the normal controls. This observation suggests sCR1 as a potential market for the assessment of disease activity in nephropathies.     

A trust-region method for H2 model reduction of bilinear systems on the Stiefel manifold

This paper investigates the Riemannian trust-region method for H₂ model reduction of bilinear systems. The H₂ error norm is treated as a cost function on the Stiefel manifold such that the orthogonality constraint for the projection matrix is plainly satisfied. The property related to the Euclidean gradient is studied. Then, the inner product associated with the Riemannian Hessian is derived, which can simplify the expression of the trust-region subproblem. The trust-region method for H₂ model reduction is accordingly established and the convergence is further discussed. Finally, two numerical examples are employed to demonstrate the performance of the proposed method.     

卤素氟化物(C_2H_5OH)nH_2O分子荧光光谱的振子强度分析

卤素氟化物是一类反应活性很强的物质,在诸多领域中有重要作用。利用高分辨快电子能量损失谱仪,采用高分辨的dipole(e,e)方法可对卤素氟化物的分子荧光光谱振子强度进行了分析,其避免了光学测量过程中存在的精度低、效率低的缺陷。在21~26 e V的能量损失区域中,检测获取卤素氟化物卤素氟化物分子荧光光谱的11S→n1P跃迁以及电离过程的光学振子强度谱,并在59~67 e V和69~74 e V的能量损失区域中,分析卤素氟化物分子荧光光谱的自电离共振过程的光学振子强度谱,实验将得到的结果同前人研究成果进行对比分析,实验结果说明所提方法获取的卤素氟化物分子荧光光谱的振子强度,同前人研究结果具有较高的匹配度,具有较高的应用价值。     

锰矿石中碳酸锰(二价锰)的测定方法浅析

碳酸锰矿是具有工业价值的重要含锰矿物之一,对锰矿资源的开发和综合利用有着重要的指导意义。有关碳酸锰的选择溶剂,先后报道的有多种,对比试验了其中常用的6种。不同溶剂对碳酸锰浸取率不一样,硫酸、磷酸、高氯酸等无机酸的稀溶液因共存的高价氧化锰矿影响,浸取率都比硝酸铝溶液的高。硝酸铝溶液是利用其水解时释放酸(稀硝酸)来作用,据文献【3】报道,在极稀的无机酸对碳酸锰矿溶解作用时,只有稀硝酸对高价氧化锰矿及含锰硅酸盐矿物的溶解度最小,干扰小,这说明硝酸铝溶液是碳酸锰的选择性溶剂。     

PBL结合案例教学法在临床医学专业本科生核医学见习教学中的应用

目的：探讨PBL结合案例教学法（CM）在临床医学专业本科生核医学见习教学中的应用价值。方法：对该校2009级及2010级学生分别采用传统的见习模式和PBL结合CM的新见习模式,见习课结束时行理论测试和临床阅片能力测试,问卷调查学生对教学的综合评价。结果：采用新见习模式的实验组学生的理论及临床阅片测试成绩均高于采用传统教学方法的对照组（P〈0.05）。实验组对教学效果、学习兴趣及课堂氛围的满意度均高于对照组。实验组学生更认可见习教学对提高包括自学能力、沟通协调能力、临床思维能力在内的综合素质的帮助。结论：PBL结合CM的见习教学新模式较传统的教学模式教学效果更好,同时能提高学生的学习主动性和培养学生的多项能力,有利于培养高素质的医学影像人才。     

复格拉斯曼流形G(2,5)中的全纯2球

利用调和序列和活动标架研究了复格拉斯曼流形G(2,5)中线性满的全纯2球.利用SU(2)的不可约酉表示构造了G(2,5)中的一些齐性全纯2球.在U(5)等价意义下确定常高斯曲率为2/3和4/3的所有线性满的退化全纯2球.最后证明在某一特定条件下常高斯曲率为4/3的非退化的全纯2球一定是U(5)等价的.     

当代科研模式呼唤研究方法的变革

当代科研模式正在发生深刻的变化 ,科研中的合作模式正在成为科研的主题模式 ,这种模式变化的深刻根源是不同学科在认识原理上存在同型性 ,应该顺应时代潮流 ,进行研究方法的变革     

铬酸钡(冷)法测定硫酸根的原理与检测要点分析

通过分析铬酸钡冷法测定硫酸根的原理,从试剂配制和检测流程两方面分析了方法的检测要点,从而对方法起到补充说明的作用。     

Investigation of ABCA1 C69T polymorphism in patients with type 2 diabetes mellitus

Introduction:

Non insulin dependent diabetes mellitus is the most common type of diabetes. Genetic factors, lipid profiles, hypertension are potential risk factors for diabetes mellitus. Adenosine binding cassette transporter proteins 1 (ABCA1) plays a role in cholesterol metabolism, especially high density lipoprotein (HDL-cholesterol). There are multiple mechanisms by which HDL-cholesterol can be atheroprotective, it is clear that the relative activity of ABCA1 plays a major role. We aimed to investigate association of ABCA1 C69T gene polymorphism with lipid levels in Turkish type 2 diabetic patients.

Materials and methods:

After isolation of DNA by ethanol precipitation we determined ABCA1 gene polymorphism by using polimerase chain reaction - restriction fragment lenght polymorphism (PCR-RFLP) method in 107 type 2 diabetic patients and 50 healthy controls.

Results:

We have observed that the frequency of TT genotype is significantly higher in healthy controls compared to patients (14% vs. 3%; P = 0.008). Also frequency of T allele was higher in controls than in patients (34% vs. 21%; P = 0.020; OR (95% CI) = 0.52 (0.30–0.88)). There was no association of lipid levels and ABCA1 C69T polymorphism subgroups.

Conclusion:

We have found significantly higher frequency of both T allele and genotype in control group when compared to patients that made us think that T allele may be a protective factor against diabetes mellitus. But, we could not find a relationship between genotypes and lipid concentrations in our two groups. Larger studies will help us to understand the relationship between ABCA1 C69T genotype and lipid parameters in diabetes mellitus.     

Scaffold fabrication in a perfusion culture microchamber array chip by O(2) plasma bonding of poly(dimethylsiloxane) protected by a physical mask

Extracellular matrix (ECM) proteins are required for cell culture. In this paper, we report the use of O(2) plasma bonding to fabricate a perfusion culture microchamber array chip with identical-size ECM spots in the isolated microchambers. The chip was fabricated by assembly of two poly(dimethylsiloxane) (PDMS) layers, a microfluidic network layer, and an ECM array layer, which were aligned and then bonded by O(2) plasma oxidation with protection of the ECM microarray with a physical mask made from PDMS. We successfully cultivated Chinese hamster ovary K1 cells in the microchambers with fibronectin. In the fibronectin microchambers, the cells adhered and extended after 12 h of static culture and then grew over the course of 1 d of perfusion culture.     

Determination method for power-saved driving motions of manipulators by heuristic algorithms (in case of PTP control)

This study proposed a method for suppressing torques and consumed energy of manipulators considering an effect of inertial forces in order to achieve power-saved drive. The present paper describes the case that the start and end points of a work path of a manipulator are specified and the path between the points can be determined arbitrarily, which is so-called point-to-point (PTP) control. The proposed method determines both the initial pose of a manipulator and input motions of its joints so that the torque or consumed energy is suppressed. The input motion of the joint is expressed by a motion curve that indicates the time profiles of input displacements, velocities and accelerations. The proposed method determines the motion curve as a polynomial with appropriate coefficients. Those coefficients and their values are decided by a heuristic algorithm in order to suppress the input torques or consumed energy of a manipulator. The paper actually determines the power-saved drive motion of “PUMA560” by the proposed method and reveals its effectiveness.     

LP(a) phenotypes and levels in angiographically proven coronary heart disease patients and controls

Lipoprotein Lp(a) excess has been identified as a powerful predictor of premature atherosclerotic vascular diseases. To evaluate this in a North-Indian population, 130 CAD patients and 130 controls were analyzed. The size of the apo(a) phenotypic isoforms was inversely proportional to Lp(a) concentrations. The mean concentration of Lp(a) in the CAD patients was 42±34 mg/dl whereas in the normal subjects it was much lower, 27±27 mg/dl. 157 subjects out of the total 260 subjects showed plasma levels of >20mg/dl. The frequency of high Lp(a) levels was much higher in patients(73%) than controls (43%). These data suggest (1) that there is heterogeneity of the Lp(a) polymorphism, (2) Higher Lp(a) levels were found in patients than in the controls, (3) Patients showed 1.5 fold increase in Lp(a) levels as compared to the controls. We conclude that low molecular weight apo(a) isoforms are significantly associated with increased risk of CAD in the North-Indian population.     

从诺贝尔科学奖看20世纪科学技术的发展

诺贝尔科学奖是20世纪科学技术发展的缩影。它向我们提供了20世纪科学技术发展的全息图景:研究方法由低级向高级发展,研究手段由单一向综合转变,研究力量由个体向群体过渡,研究中心由欧洲向美国转移。正确认识这些特点和规律,对于科学把握21世纪科学技术的发展趋势,具有重要意义。