An analysis of underlying factors for seasonal variation in gonorrhoea in India: A 6-year statistical assessment

Purpose: A statistical assessment of a disease is often necessary before resources can be allocated to any control programme. No literature on seasonal trends of gonorrhoea is available from India. Objectives: The objectives were (1) to determine, if any, seasonal trends were present in India (2) to describe factors contributing to seasonality of gonorrhoea (3) to formulate approaches for gonorrhoea control at the national level. Materials and Methods: Seasonal indices for gonorrhoea were calculated quarterly in terms of a seasonal index between 2005 and 2010. Ratio-to-moving average method was used to determine the seasonal variation. The original data values in the time-series were expressed as percentages of moving averages. Results were also analyzed by second statistical method i.e. seasonal subseries plot. Results: The seasonally adjusted average for culture-positive gonorrhoea cases was highest in the second quarter (128.61%) followed by third quarter (108.48%) while a trough was observed in the first (96.05%) and last quarter (64.85%). The second quarter peak was representative of summer vacations in schools and colleges. Moreover, April is the harvesting month followed by celebrations and social gatherings. Both these factors are associated with increased sexual activity and partner change. A trough in first and last quarter was indicative of festival season and winter leading to less patients reporting to the hospital. Conclusion: The findings highlight the immediate need to strengthen sexual health education among young people in schools and colleges and education on risk-reduction practices especially at crucial points in the calendar year for effective gonorrhoea control.     

Quantitative chemical exchange saturation transfer (qCEST) MRI – omega plot analysis of RF‐spillover‐corrected inverse CEST ratio asymmetry for simultaneous determination of labile proton ratio and exchange rate

Chemical exchange saturation transfer (CEST) MRI is sensitive to labile proton concentration and exchange rate, thus allowing measurement of dilute CEST agent and microenvironmental properties. However, CEST measurement depends not only on the CEST agent properties but also on the experimental conditions. Quantitative CEST (qCEST) analysis has been proposed to address the limitation of the commonly used simplistic CEST‐weighted calculation. Recent research has shown that the concomitant direct RF saturation (spillover) effect can be corrected using an inverse CEST ratio calculation. We postulated that a simplified qCEST analysis is feasible with omega plot analysis of the inverse CEST asymmetry calculation. Specifically, simulations showed that the numerically derived labile proton ratio and exchange rate were in good agreement with input values. In addition, the qCEST analysis was confirmed experimentally in a phantom with concurrent variation in CEST agent concentration and pH. Also, we demonstrated that the derived labile proton ratio increased linearly with creatine concentration (P < 0.01) while the pH‐dependent exchange rate followed a dominantly base‐catalyzed exchange relationship (P < 0.01). In summary, our study verified that a simplified qCEST analysis can simultaneously determine labile proton ratio and exchange rate in a relatively complex in vitro CEST system. Copyright © 2015 John Wiley & Sons, Ltd.     

Impedance of a goat eye lens

The complex electrical impedance of a goat eye lens is studied in the frequency range 10mHz−10Hz at room temperature, using a computer-controlled AC impedance system. AC impedance software (model 368, version 2.2) is employed to determine the total impedance and capacitance of the eye lens at various frequencies. A Cole-Cole plot of the eye lens material is drawn between the real component of impedance Z′ and the imaginary component Z″ for each excitation frequency that shows a perfect arc of a semicircle, with its centre lying below the abscissa at an angle of 35°. The half-angle ϕ between R₀ and R_∞ is found to be 55°, which mathematically demonstrates the selective permeability of the eye lens. Using graphical analysis of the Cole-Cole plot, characteristic frequency f_c and distribution factor α are observed to be 1Hz and 0.77, respectively. At characteristic frequency, capacitance and total impedance are found to be 1.14μF and 9.08kΩ. The effect of electrode polarisation on capacitance is corrected, based on Fricke's power function. The observed electrical parameters are then used to explain the multiple current path through various tissue compartments. Further, an attempt is made to explain the results on the basis of a possible dipolar model.     

正常人血小板介电谱的实验研究

在100KHz～110MHz范围内,测量人血小板的介电谱,分析了人血小板对交流电场的介电响应的数据特征。利用频域阻抗技术首次测量了正常人血小板交流阻抗,绘制血小板的介电常数和电导率与电场频率的关系曲线。建立了人血小板的介电谱和Cole-Cole图,明确了人血小板的介电频响的数据特征。在射频电场中,人血小板的介电常数和电导率具有频率依赖性,血小板介电谱具有两个特征频率:第一特征频率fC1为6.66MHz,第二特征频率fC2为9.81MHz。     

Newly exposed immunochemically cross-reactive epitopes in sperm-specific LDH after glucosylation and gossypol interaction

PROBLEM: In a previous study, mouse lactate dehydrogenase-C4 (LDH-C4) after chemical modifications with gossypol (Gossy-LDH-C4) and glucosylation with lactose (Glu-LDH-C4) was found to induce high immunological infertility in allogenic mice. In the present study, the characterization of antibodies and cross reactivity of the antisera produced against Gossy- and Glu-LDH-C4 with purified somatic isozymes are being reported. METHODS: Allo-antisera generated in Balb/c mice (i.r. route) against one primary (50 microg) and two secondary doses (30 x 2 microg) in Al(OH)3 were tested for cross-reactivity by ELISA and antibody avidity using Scatchard plot and Sip's plot. RESULTS: Results suggested that IgG against native LDH-C4 failed to recognize somatic isozyme, while antisera against chemically modified LDH-C4 consistently reacted with purified LDH from kidney and placenta. Scatchard plots and antibody saturation curves of native and complexed LDH supported the presence of heterogenous antibodies with a mean association constant (Ka) of the order of 10(6)-10(7) M(-1), whereas diversity of heterogeneity, defined by diversity constant (a), ranged between 0.89 and 1.23. In general, anti-Glu-LDH-C4 antiserum and native LDH-C4. reacted with higher Ka (low affinity) with a diversity constant of 0.89 compared with interaction between native LDH-C4 and it's antibodies. CONCLUSIONS: It is concluded that LDH-C4 is not an immunochemically sperm-specific protein, in which crossreactive epitopes are hidden within its conformation. Due to the large intake of cotton seed (a source of gossypol) by cattle, its unrefined oil by humans in various parts of the world, and the prevelance of diabetic state all the world over, the present study warns of immunological consequences in situ following gossypol interaction and glucosylation of LDH and conformationally related proteins in circulation.     

配合物分子印迹聚合物的识别性能

以乙酸镍和2,2′-联吡啶配合物为模板、4-乙烯吡啶为功能单体、乙二醇二甲基丙烯酸酯为交联剂,合成了具有类似金属螯合抗体结合位点的金属配合物印迹聚合物,系统研究了金属离子对模板聚合物选择性结合2,2′-联吡啶的调节作用。结果表明:印迹聚合物对N i(Ⅱ)-2,2′-联吡啶配合物有选择性识别能力。采用Scatchard模型评价分子印迹聚合物的结合特性,得到高亲和力结合位点的平衡离解常数Kd1=0.082 mm o l/L,表观最大结合量Qm ax1=82.2μm o l/g,低亲和力结合位点的Kd2=0.400 mm o l/L,Qm ax2=91.3μm o l/g。     

Components of variance

Components of variance have a long history and find application in all areas of scientific investigation. This review introduces components of variance and their importance firstly by examples on blood pressure, proteomic data, breath analysers and esophageal pH monitoring devices. We then present an intuitive geometric representation of analysis of variance and explain how the components of variance can be estimated from the analysis of variance table. We conclude by suggesting practice points for studies which incorporate components of variance, and recommend commonly used statistical software to undertake such analysis.     

A Review of: “ Handbook of Adaptive Designs in Pharmaceutical and Clinical Development,by A. Pong and S.-C. Chow (Eds.)”

In practice, there exist many disease processes with three ordinal disease classes; for example, in the detection of Alzheimer’s disease (AD) a patient can be classified as healthy (disease-free stage), mild cognitive impairment (early disease stage), or AD (full disease stage). The treatment interventions and effectiveness of such disease processes will depend on the disease stage. Therefore, it is important to develop diagnostic tests with the ability to discriminate between the three disease stages. Measuring the overall ability of diagnostic tests to discriminate between the three classes has been discussed extensively in the literature. However, there has been little proposed on how to select clinically meaningful thresholds for such diagnostic tests, except for a method based on the generalized Youden index by Nakas et al. (2010). In this article, we propose two new criteria for selecting diagnostic thresholds in the three-class setting. The numerical study demonstrated that the proposed methods may provide thresholds with less variability and more balance among the correct classification rates for the three stages. The proposed methods are applied to two real examples: the clinical diagnosis of AD from the Washington University Alzheimer’s Disease Research Center and the detection of liver cancer (LC) using protein segments.     

Optimising nearest neighbour information—a simple,efficient sampling strategy for forestry plot imputation using remotely sensed data

The rapid adoption of LiDAR-assisted forest inventory, together with nearest neighbour imputation, has created new challenges for those involved in sample selection. It is not obvious a priori what type of sample will be the most efficient when used with imputation. In this paper we explore a number of sampling approaches, including conventional methods such as stratification, spatial methods based on tessellations, and balanced sampling. We introduce a new approach called nearest centroid (NC) that optimises the survey design by using the distance properties of the sample in the space defined by the auxiliary variables, and examine this and other methods across a range of survey situations and objectives. The NC method is shown to be highly efficient when compared with other methods and is very flexible in the way it can be implemented.