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This work proposes a simple method, based on the crystal rotation technique and heterodyne interferometry, to simultaneously determine the pretilt angle and cell gap of nematic liquid crystal cells. When heterodyne light passes through a nematic liquid crystal cell, the phase retardation given by the characteristic parameters of the cell can be measured accurately by heterodyne interferometry. This phase retardation relates to the pretilt angle, cell gap, and angle of incidence on the cell. By using the measured phase retardations at two incident angles, the pretilt angle and cell gap of the nematic liquid crystal cell can be estimated by numerical analysis. This method is feasible, requiring only two incident angles and prior knowledge of two characteristic parameters--extraordinary and ordinary refractive indices of the liquid crystal. It is characterized by the advantages of simplicity of installation, ease of operation, high stability, high accuracy, and high resolution.

Recently, the use of artificial intelligence based data mining techniques for massive medical data classification and diagnosis has gained its popularity, whereas the effectiveness and efficiency by feature selection is worthy to further investigate. In this paper, we presents a novel method for feature selection with the use of opposite sign test (OST) as a local search for the electromagnetism-like mechanism (EM) algorithm, denoted as improved electromagnetism-like mechanism (IEM) algorithm. Nearest neighbor algorithm is served as a classifier for the wrapper method. The proposed IEM algorithm is compared with nine popular feature selection and classification methods. Forty-six datasets from the UCI repository and eight gene expression microarray datasets are collected for comprehensive evaluation. Non-parametric statistical tests are conducted to justify the performance of the methods in terms of classification accuracy and Kappa index. The results confirm that the proposed IEM method is superior to the common state-of-art methods. Furthermore, we apply IEM to predict the occurrence of Type 2 diabetes mellitus (DM) after a gestational DM. Our research helps identify the risk factors for this disease; accordingly accurate diagnosis and prognosis can be achieved to reduce the morbidity and mortality rate caused by DM.

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Multiple sclerosis (MS) is an inflammatory neurological disease characterized by autoimmune-mediated demyelination of the central nervous system. Genetic and environmental factors may contribute to the development of MS. This has not been confirmed yet. Dental amalgam has long been controversial in MS due to its mercury content but the toxicological implications of mercury-containing amalgam fillings (AMF) for MS remain to be elucidated. We conducted a case–control study to investigate the association between AMF and the risk of MS from the Taiwanese National Health Insurance Research Database (NHIRD). Case (n = 612) and control (n = 612) groups were matched by sex, age, urbanization level, monthly income, and Charlson comorbidity index by propensity score matched with a 1:1 ratio from 2000 to 2013. Differences between cases and controls was not statistically significant (OR: 0.82, 95% CI = 0.65–1.05). In subjects stratified by gender, MS was also not associated with AMF for women (OR: 0.743, 95% CI = 0.552–1.000) and men (OR: 1.006, 95% CI = 0.670–1.509), respectively. In summary, this Taiwanese nationwide population-based case–control study did not find an association between MS and AMF.

Essential tremor (ET) is a common neurological disorder and the most common movement disorder. Low-level occupational exposure to mercury vapor is known to be a crucial factor that increases the risk of tremor. Dental amalgam is one of the main sources of mercury in those who possess amalgam restorations. However, the relationship between ET and amalgam filling (AMF) is not quite clear. The purpose of this study was to investigate the association between AMF and the risk of ET using a population-based administrative databank. The data for this study were sourced from the Taiwanese National Health Insurance Research Database (NHIRD). A retrospective case-control study was conducted using this databank from 2000 to 2013. Case and control groups were matched by sex, age, urbanization level, monthly income, and Charlson comorbidity index using the propensity score method with a 1:1 ratio. In this study, 3008 cases and 3008 controls were included. The results from this nationwide population-based case-control study did not indicate any association between ET and AMF in Taiwan. Although the results were not significantly statistical, the findings may be worthy to be valued.