72 research outputs found

    Jeong, H.; Jeon, S. Determination of Dopamine in the Presence of Ascorbic Acid by Nafion and Single-Walled Carbon Nanotube Film Modified on Carbon Fiber Microelectrode. Sensors 2008, 8, 6924-6935

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    Carbon fiber microelectrode (CFME) modified by Nafion and single-walled carbon nanotubes (SWNTs) was studied by voltammetric methods in phosphate buffer saline (PBS) solution at pH 7.4. The Nafion-SWNTs/CFME modified microelectrode exhibited strongly enhanced voltammetric sensitivity and selectivity towards dopamine (DA) determination in the presence of ascorbic acid (AA). Nafion-SWNTs film accelerated the electron transfer reaction of DA, but Nafion film as a negatively charged polymer restrained the electrochemical response of AA. Voltammetric techniques separated the anodic peaks of DA and AA, and the interference from AA was effectively excluded from DA determination. Linear calibration plots were obtained in the DA concentration range of 10 nM - 10 μM and the detection limit of the anodic current was determined to be 5 nM at a signal-to-noise ratio of 3. The study results demonstrate that DA can be determined without any interference from AA at the modified microelectrode, thereby increasing the sensitivity, selectivity, and reproducibility and stability

    Monte Carlo simulation-based defect ratio estimation approach for a chemical materials stockpile reliability program

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    A chemical material stockpile reliability program (CSRP) that determines the usability, safety, reliability, and performance of chemical equipment and materials is developed to determine the storage or disposal of chemical material stockpile (Storage Chemical Equipment and Material Reliability Evaluation Instruction, 2019). However, current inspection for current CSRP depend on test and evaluation of criteria for level of importance, and so the number of samples and acceptance quality limit (AQL) are presented based on the lot size. All the processes are conducted under KS Q ISO 2859-1, and the defect rate of the entire lot of CSRP items is generally assumed to be a distribution that is similar to a binomial distribution. However, the pass-fail test for CSRP items is based on approximately 10 test items, and the factors that cause defects in these items are also heterogeneous. We propose a new methodology for estimating the defect rates of CSRP items based on Monte Carlo simulations, which are widely used in various academic fields. In addition, we show the future applicability of the methodology by applying it to the K1 gas mask case and revealing the results of the defect rate estimation. We also present future work, including the need for a standard sample of CSRP items

    Monte Carlo simulation-based defect ratio estimation approach for a chemical materials stockpile reliability program

    Get PDF
    A chemical material stockpile reliability program (CSRP) that determines the usability, safety, reliability, and performance of chemical equipment and materials is developed to determine the storage or disposal of chemical material stockpile (Storage Chemical Equipment and Material Reliability Evaluation Instruction, 2019). However, current inspection for current CSRP depend on test and evaluation of criteria for level of importance, and so the number of samples and acceptance quality limit (AQL) are presented based on the lot size. All the processes are conducted under KS Q ISO 2859-1, and the defect rate of the entire lot of CSRP items is generally assumed to be a distribution that is similar to a binomial distribution. However, the pass-fail test for CSRP items is based on approximately 10 test items, and the factors that cause defects in these items are also heterogeneous. We propose a new methodology for estimating the defect rates of CSRP items based on Monte Carlo simulations, which are widely used in various academic fields. In addition, we show the future applicability of the methodology by applying it to the K1 gas mask case and revealing the results of the defect rate estimation. We also present future work, including the need for a standard sample of CSRP items

    Dissociation of ssDNA - Single-Walled Carbon Nanotube Hybrids by Watson-Crick Base Pairing

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    The unwrapping event of ssDNA from the SWNT during the Watson-Crick base paring is investigated through electrical and optical methods, and binding energy calculations. While the ssDNA-metallic SWNT hybrid shows the p-type semiconducting property, the hybridization product recovered metallic properties. The gel electrophoresis directly verifies the result of wrapping and unwrapping events which was also reflected to the Raman shifts. Our molecular dynamics simulations and binding energy calculations provide atomistic description for the pathway to this phenomenon. This nano-physical phenomenon will open up a new approach for nano-bio sensing of specific sequences with the advantages of efficient particle-based recognition, no labeling, and direct electrical detection which can be easily realized into a microfluidic chip format.Comment: 4 pages, 4 figure

    Sex/Gender and Socioeconomic Differences in the Predictive Ability of Self-Rated Health for Mortality

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    Background: Studies have reported that the predictive ability of self-rated health (SRH) for mortality varies by sex/gender and socioeconomic group. The purpose of this study is to evaluate this relationship in Japan and explore the potential reasons for differences between the groups. Methodology/Principal Findings: The analyses in the study were based on the Aichi Gerontological Evaluation Study's (AGES) 2003 Cohort Study in Chita Peninsula, Japan, which followed the four-year survival status of 14,668 community-dwelling people who were at least 65 years old at the start of the study. We first examined sex/gender and education-level differences in association with fair/poor SRH. We then estimated the sex/gender- and education-specific hazard ratios (HRs) of mortality associated with lower SRH using Cox models. Control variables, including health behaviors (smoking and drinking), symptoms of depression, and chronic co-morbid conditions, were added to sequential regression models. The results showed men and women reported a similar prevalence of lower SRH. However, lower SRH was a stronger predictor of mortality in men (HR = 2.44 [95% confidence interval (CI): 2.14–2.80]) than in women (HR = 1.88 [95% CI: 1.44–2.47]; p for sex/gender interaction = 0.018). The sex/gender difference in the predictive ability of SRH was progressively attenuated with the additional introduction of other co-morbid conditions. The predictive ability among individuals with high school education (HR = 2.39 [95% CI: 1.74–3.30]) was similar to that among individuals with less than a high school education (HR = 2.14 [95% CI: 1.83–2.50]; p for education interaction = 0.549). Conclusions: The sex/gender difference in the predictive ability of SRH for mortality among this elderly Japanese population may be explained by male/female differences in what goes into an individual's assessment of their SRH, with males apparently weighting depressive symptoms more than females

    Correlations between Forgetfulness and Social Participation: Community Diagnosing Indicators

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    We analyzed the relationships between forgetfulness and social participation, social contact, and social support by municipality to develop community diagnosing indicators. The analysis subjects included 105 municipalities that agreed to provide data for the 2013 Survey of Needs in Spheres of Daily Life in Japan (n = 338,659 people). Forgetfulness as a risk factor for dementia was used as the dependent variable. The variables of social environment factors were (1) social participation, (2) social contact, and (3) social support. The ratio of people responding that they experienced forgetfulness differed among municipalities, with a mean of 19.0% (7.1–35.6%). Higher levels of social participation, social contact, and social support were associated with lower levels of forgetfulness, even after adjusting for age and regional variables. The results of the present study suggest that it is appropriate to use forgetfulness and social participation at least a few times a year in any social activity as community diagnosing indicators. Municipalities could encourage their inhabitants to participate by developing and providing engaging social activities

    Did the Number of Older People Requiring Long-Term Care and Expenditure Increase after the 2011 Great East Japan Earthquake? Analysis of Changes over Six Years

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    On 11 March 2011, the great earthquake hit Japan, resulting in 15,895 deaths, 6156 serious injuries, and 2539 missing persons. This event affected the health and lives of older residents, and reports showed an increase in the number of people eligible for long-term care afterward. In this study, among the places affected by the 2011 Great East Japan Earthquake and tsunami, we focused on 15 municipalities, including designated municipalities based on the Special Act on Nuclear Evacuation in Fukushima Prefecture, and aimed to clarify the medium-term effects (six years post-disaster) on the long-term care certification rate and expenditure for provision of services. We used the Ministry of Health, Labour, and Welfare Monthly Status Report on Long-Term Care Insurance and the Ministry of Internal Affairs and Communications Population Register for 2011, 2014, and 2017. In 2011, we found no intergroup differences among the 15 Fukushima municipalities and other municipalities in either the long-term care certification rate or the per-person expenditure for use of services. In 2014, after the earthquake, the long-term care certification rate was 5.4% higher in the 15 Fukushima municipalities than in other municipalities for those aged 75 years or older. The rate of 2014–2017 has not increased significantly, partly because of stability after the disaster and change in the population structure. Nevertheless, the long-term care certification rate in the 15 Fukushima municipalities is higher than that of the other two groups even after six years since the earthquake. Similarly, the per-person expenditure for use of services for one month was 11,800 yen higher in the 15 Fukushima municipalities than in other municipalities in 2014, and this trend continued into 2017. Strong, ongoing governmental support is needed, especially for those aged 75 or older, following a disaster

    Analytic framework for understanding the competing multiple light scattering processes

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    In many complex physical phenomena such as wave propagation in scattering media, the process of interest often cannot be easily distinguished from other processes because only the total combined process is accessible. This makes it difficult to extract the precise knowledge of each subprocess. Here, we derive an analytic expression describing the way the eigenchannel coupling of the total process distributes its energy to the individual subprocesses, with only partial information on each subprocess such as the average eigenvalue γ€ˆΟ„γ€‰ and enhancement factor Ξ·. We found that the ratio of (Ξ· βˆ’ 1)γ€ˆΟ„γ€‰ between two subprocesses is a critical parameter determining the preferable subprocess in the energy coupling. This work provides a new analytic framework for understanding the effect of wavefront shaping in the control of wave propagation in disordered media. Β© 2019, The Author(s
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