Machine learning for the diagnosis of early stage diabetes using temporal glucose profiles

Machine learning shows remarkable success for recognizing patterns in data. Here we apply the machine learning (ML) for the diagnosis of early stage diabetes, which is known as a challenging task in medicine. Blood glucose levels are tightly regulated by two counter-regulatory hormones, insulin and glucagon, and the failure of the glucose homeostasis leads to the common metabolic disease, diabetes mellitus. It is a chronic disease that has a long latent period the complicates detection of the disease at an early stage. The vast majority of diabetics result from that diminished effectiveness of insulin action. The insulin resistance must modify the temporal profile of blood glucose. Thus we propose to use ML to detect the subtle change in the temporal pattern of glucose concentration. Time series data of blood glucose with sufficient resolution is currently unavailable, so we confirm the proposal using synthetic data of glucose profiles produced by a biophysical model that considers the glucose regulation and hormone action. Multi-layered perceptrons, convolutional neural networks, and recurrent neural networks all identified the degree of insulin resistance with high accuracy above $85\%$.Comment: 4 pages, 2 figur

Micromechanical characterization of single-crystalline niobium at low temperature

Due to the significant interests in application of micro-electro-mechanical system to devices used in harsh environments, small-scale mechanical behaviors in different thermal environments have been extensively studied recently. Particularly, the study on mechanical behavior of body-centered-cubic (bcc) metals has received a strong attention because of the significant temperature dependence of screw dislocation mobility and its cross-slip probability. So far, most studies have been done in either room temperature or elevated temperature, but a low temperature study is relatively scarce. In this work, we present our recent development of in-situ cryogenic micromechanical testing system and the results of cryogenic micro-tensile tests on a [0 0 1] bcc niobium single crystal. The dog-bone shaped tensile samples were fabricated via focused-ion beam milling and were tested at room temperature, 100K and 56K. The decrease in temperature increased the flow strengths. In addition, stress-strain curves at room temperature were smooth, but those at 56 and 100K showed a few distinctively large strain bursts. Post-mortem scanning electron microscopy revealed that necking region of samples tested at room temperature underwent uniform and homogeneous plastic deformation, but that at low temperature underwent highly localized plastic deformation followed by brittle fracture with limited ductility. Thus, micro-tensile tests of niobium single crystal show the ductile-to-brittle transition. All the results will be discussed in terms of the temperature dependence of cross-slip and intrinsic lattice resistance of screw dislocation. Our results will enable a deeper understanding of the combined effects of sample dimension and temperature on plasticity and fracture processes in bcc metals

Atomic arrangement and mechanical properties of chemical vapor deposited amorphous boron

Amorphous boron fiber has been widely used as a reinforcement filler in aerospace resin-matrix composites due to its high strength and high elastic modulus. However, its mechanical properties have not been measured accurately due to intrinsic issues during fabrication. Amorphous boron is most commonly produced in singlefilament reactors by chemical vapor deposition of boron on tungsten wire, and the final product is a core-shell wire with a tungsten boride core and amorphous boron shell. Traditionally, wire tension tests of the composite fiber or hollow amorphous boron fiber have been conducted but this method would underestimate the strength due to the greater probability of defects along the long wire. Micropillar compression and tension testing enable us to determine mechanical properties of small materials accurately. In addition, the local atomic arrangement in amorphous boron has not been clearly understood because of the complexity in its amorphous structure. Therefore, it is necessary to conduct advanced transmission electron microscopy (TEM) to analyze the local structure at atomic resolution. Please download the PDF file for full content

Shear localization and size-dependent strength of YCd6 quasicrystal approximant at the micrometer length scale

Mechanical properties of materials are strongly dependent of their atomic arrangement as well as the sample dimension, particularly at the micrometer length scale. In this study, we investigated the small-scale mechanical properties of single-crystalline YCd6, which is a rational approximant of the icosahedral Y-Cd quasicrystal. In situ microcompression tests revealed that shear localization always occurs on {101} planes, but the shear direction is not constrained to any particular crystallographic directions. Furthermore, the yield strengths show the size dependence with a power law exponent of 0.4. Shear localization on {101} planes and size-dependent yield strength are explained in terms of a large interplanar spacing between {101} planes and the energetics of shear localization process, respectively. The mechanical behavior of the icosahedral Y-Cd quasicrystal is also compared to understand the influence of translational symmetry on the shear localization process in both YCd6 and Y-Cd quasicrystal micropillars. The results of this study will provide an important insight in a fundamental understanding of shear localization process in novel complex intermetallic compounds

Vertical ridge augmentation feasibility using unfixed collagen membranes and particulate bone substitutes: A 1- to 7-year retrospective single-cohort observational study

AIM To determine whether vertical ridge augmentation (VRA) can be obtained through guided bone regeneration (GBR) using exclusively resorbable collagen membranes and particulate bone substitutes without additional stabilization. MATERIALS AND METHODS This study retrospectively examined 22 participants who underwent VRA with staged or simultaneous implant placement. The vertical defects of all participants were filled with particulate bone substitutes and covered with resorbable collagen membranes. The augmented sites were stabilized with unfixed collagen membranes and the flap without any additional fixation. The augmented tissue height was assessed using cone-beam computed tomography at baseline, immediately after surgery, and at annual follow-ups. RESULTS The vertical bone gain of the 22 augmented sites amounted to 6.48 ± 2.19 mm (mean ± SD) immediately after surgery and 5.78 ± 1.72 mm at 1- to 7-year follow-up. Of the 22 augmented sites, 18 exhibited changes of less than 1 mm, while the other 4 showed changes of greater than 1 mm. Histological observation of three representative cases revealed new bone apposition on the remaining material. CONCLUSION The present findings indicate that GBR procedures using exclusively collagen membranes and particulate biomaterials without any additional fixation are feasible options for VRA

Staphylococcal enterotoxin sensitization in a community-based population : a potential role in adult-onset asthma

Background: Recent studies suggest that Staphylococcus aureus enterotoxin sensitization is a risk factor for asthma. However, there is a paucity of epidemiologic evidence on adult-onset asthma in community-based populations. Objective: We sought to evaluate the epidemiology and the clinical significance of staphylococcal enterotoxin sensitization in community-based adult populations. Methods: The present analyses were performed using the baseline data set of Korean adult population surveys, consisting of 1080 adults (mean age=60.2years) recruited from an urban and a rural community. Questionnaires, methacholine challenge tests, and allergen skin tests were performed for defining clinical phenotypes. Sera were analysed for total IgE and enterotoxin-specific IgE using ImmunoCAP. Results: Staphylococcal enterotoxin sensitization (0.35kU/L) had a prevalence of 27.0%. Risk factors were identified as male sex, current smoking, advanced age (61years), and inhalant allergen sensitization. Current asthma was mostly adult onset (18years old) and showed independent associations with high enterotoxin-specific IgE levels in multivariate logistic regression tests. In multivariate linear regressions, staphylococcal enterotoxin-specific IgE level was identified as the major determinant factor for total IgE level. Conclusions and Clinical Relevance: Staphylococcal enterotoxin sensitization was independently associated with adult-onset asthma in adult community populations. Strong correlations between the enterotoxin-specific IgE and total IgE levels support the clinical significance. The present findings warrant further studies for the precise roles of staphylococcal enterotoxin sensitization in the asthma pathogenesis

Experimental and Numerical Analysis of Streamers in Pulsed Corona and Dielectric Barrier Discharges

Streamer characteristics have been experimentally and numerically analyzed for pulsed corona discharge (PCD) and dielectric barrier discharge (DBD) to find out how the discharge methods determine them and how they, in turn, affect the generation of radicals in flue gases. Experiments have been performed and compared for decomposition of a nitrogen oxide (NO) using PCD and DBD, and the electric field and average electron energy in the streamer are measured in each discharge by using line ratio of N2+ to N2*. The measured results of electron energy reasonably explain in terms of G-value how the measured NO removal efficiencies have come out. The PCD having high electron energy turns out to be more efficient for generating N radicals, whereas the DBD containing relatively low electron energy is more effective for producing O radicals. 3-D and 1-D numerical simulations have been carried out to understand the observed streamer dynamics in both the PCD and DBD reactors. The 3-D numerical simulation has successfully illustrated the images of streamer front propagation in a wire-cylinder PCD reactor. In the 1-D simulation for the DBD, the recurrence phenomena of streamers have numerically appeared during the rising phase of an AC voltage. Furthermore, these numerical models have properly predicted the electric fields that are comparable with the corresponding average electron energies estimated from the emission spectral measurements for the PCD and DBD

Occupational Factors Associated with Changes in the Body Mass Index of Korean Male Manual Workers

OBJECTIVES: This study was carried out to analyze and compare the occupational factors that could influence changes in body mass index (BMI) in male manual workers stratified into short-term and long-term work experience groups. METHODS: The subjects were 299 male manual workers (sampled systematically) from 27 workplaces, who had undergone travelling medical examinations at a university hospital between March 28 and May 10, 2013, and had also undergone medical examinations at the same hospital in 2012. Their general and occupational characteristics were investigated through a structured, self-administered questionnaire. The BMI at each point in time was calculated based on the anthropometric results of the medical examinations. Multiple regression analyses were conducted on outcomes of the BMI change and predictors composed of the general and occupational characteristics, with the subjects stratified into groups with 5 years or less (short-term) versus more than 5 years (long-term) of work experience at the present post. RESULTS: In the short-term work experience group, the BMI increases of 3-shift workers and groups reporting disagreement with feeling “insufficient job control” and “lack of reward” at work, two of the subscales of job stress, were significantly higher than those of daytime workers and high-stress groups, respectively. In the long-term work experience group, However, although the BMI increase for 3-shift workers was also significantly higher than that of daytime workers, none of the job stress factors were significantly associated with a BMI increase, whereas the social factors of education and marital status were significant, and some lifestyle factors (such as smoking and regular exercise) were also significant. CONCLUSION: This study showed that, except for 3-shift work, the factors associated with BMI increase could differ depending on the length of job experience. Consequently, different strategies may be needed for workers with short-term versus long-term job experience when designing interventions for preventing their obesity

Acute Symptoms after a Community Hydrogen Fluoride Spill

OBJECTIVES: This study was conducted to describe the demographic characteristics, and clinical signs and symptoms of patients who visited a general hospital because of the release of chemically hazardous hydrogen fluoride that occurred on September 27, 2012 in Gumi City, Korea. METHODS: The medical records at 1 general hospital 9 km from the accident site were reviewed using a standardized survey format. There were 1,890 non-hospitalized and 12 hospitalized patients exposed to hydrogen fluoride between September 27 and October 13 2012. RESULTS: Among the 12 hospitalized patients, 11 were discharged within 1 week and the other was hospitalized for 10 days. The chief complaints were respiratory symptoms such as hemoptysis and shortness of breath, gastrointestinal symptoms, neurologic symptoms, sore throat, and lip burn. The number of non-hospitalized patients exhibited a bimodal distribution, peaking on the first and twelfth days after the accident. Their chief complaints were sore throat (24.1%), headache (19.1%), cough (13.1%), and eye irritation (9.2%); some patients were asymptomatic (6.2%). Patients who visited the hospital within 3 days (early patients) of the spill more often had shortness of breath (27.0%) and nausea (6.3%) as the chief complaints than patients who visited after 3 days (late patients) (3.5% and 2.6%, respectively). However, cough and rhinorrhea were more common in the late patients (14.0% and 3.3%, respectively) than in the early patients (5.0% and 0.0%, respectively). Patients who were closer to the accident site more often had shortness of breath and sputum as the chief complaints than patients who were farther away. The mean serum calcium concentration was 9.37 mg/dL (range: 8.4–11.0 mg/dL); none of the patients had a decreased serum calcium level. Among 48 pulmonary function test results, 4 showed decreased lung function. None of the patients had abnormal urine fluoride levels on the eighth day after exposure. CONCLUSIONS: Patients hospitalized due to chemical hazard release of hydrogen fluoride had acute respiratory, gastrointestinal, and neurologic health problems. Non-hospitalized patients have acute symptoms mainly related to upper respiratory irritation

Could Fractional Exhaled Nitric Oxide Test be Useful in Predicting Inhaled Corticosteroid Responsiveness in Chronic Cough? A Systematic Review

© 2016 Background Fractional exhaled nitric oxide (FENO) is a safe and convenient test for assessing T H 2 airway inflammation, which is potentially useful in the management of patients with chronic cough. Objective To summarize the current evidence on the diagnostic usefulness of FENO for predicting inhaled corticosteroid (ICS) responsiveness in patients with chronic cough. Methods A systematic literature review was conducted to identify articles published in peer-reviewed journals up to February 2015, without language restriction. We included studies that reported the usefulness of FENO (index test) for predicting ICS responsiveness (reference standard) in patients with chronic cough (target condition). The data were extracted to construct a 2 × 2 accuracy table. Study quality was assessed with Quality Assessment of Diagnostic Accuracy Studies 2. Results We identified 5 original studies (2 prospective and 3 retrospective studies). We identified considerable heterogeneities in study design and outcome definitions, and thus were unable to perform a meta-analysis. The proportion of ICS responders ranged from 44% to 59%. Sensitivity and specificity ranged from 53% to 90%, and from 63% to 97%, respectively. The reported area under the curve ranged from abou t 0.60 to 0.87; however, studies with a prospective design and a lower prevalence of asthma had lower area under the curve values. None measured placebo effects or objective cough frequency. Conclusions We did not find strong evidence to support the use of FENO tests for predicting ICS responsiveness in chronic cough. Further studies need to have a randomized, placebo-controlled design, and should use validated measurement tools for cough. Standardization would facilitate the development of clinical evidence