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OBJECTIVES: The COVID-19 pandemic has forced people to change many behaviours, including physical distancing, hygiene measures and lifestyles. This study aimed to evaluate the indirect impact of the COVID-19 pandemic on the incidence of non-COVID-19 infections and medical care costs/visits using health insurance claims. STUDY DESIGN: This was an observational study using patient-based administrative claims covering approximately 800,000 insured persons and their dependents in the Mie Prefecture in Japan. METHODS: This study identified non-COVID-19 infectious disease incidences, number of outpatient visits and healthcare costs between 2017 and 2021. Each year was divided into quarters. The adjusted incidence rate ratios (IRRs) during the pandemic (January 2020 to September 2021) and during the prepandemic period (January 2017 to December 2019) were determined using Poisson regression. RESULTS: The adjusted influenza IRRs from April 2020 were close to zero. The incidence of upper respiratory tract infections and bacterial pneumonia was significantly reduced (IRRs range: 0.39-0.73 and 0.43-0.84, respectively). Gastrointestinal and urinary tract infection incidences decreased by approximately 30% and 10%, respectively. In contrast, sexually transmitted infections (STIs), including syphilis, gonococcal infection and Chlamydia trachomatis infection, did not decrease during the pandemic but increased significantly between April and June 2021 (adjusted IRR, 1.37; 95% confidence interval, 1.18-1.60). The adjusted IRRs for outpatient visits and healthcare costs were 0.86-0.93 and 0.91-0.97, respectively. CONCLUSIONS: In contrast to other infections, STIs did not decrease during the COVID-19 pandemic. The IRR of STIs during the pandemic period is an area of public health concern. Appropriate screening and medical consultations are strongly recommended.
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COVID-19 , Infecções Sexualmente Transmissíveis , Humanos , COVID-19/epidemiologia , COVID-19/prevenção & controle , Incidência , Pandemias , Japão/epidemiologia , Infecções Sexualmente Transmissíveis/epidemiologia , Infecções Sexualmente Transmissíveis/prevenção & controleRESUMO
OBJECTIVE: Endoscopic hydro-mastoidectomy, in which mastoidectomy is performed underwater, can be employed during transcanal endoscopic ear surgery for cholesteatoma removal. It was hypothesised that endoscopic hydro-mastoidectomy might take less time than endoscopic non-underwater mastoidectomy because the endoscope does not need to be removed for cleaning. METHODS: This study compared the mastoidectomy and total operative durations between the endoscopic hydro-mastoidectomy (n = 25) and endoscopic non-underwater drilling (control, n = 8) groups. Moreover, it compared the size of resected areas of the external auditory canal between the two groups. RESULTS: The mastoidectomy time of the endoscopic hydro-mastoidectomy group was significantly shorter than that of the control group (p < 0.01). The total operative time did not differ significantly between the endoscopic hydro-mastoidectomy and control groups (p = 0.17). The resected area was significantly larger in the endoscopic hydro-mastoidectomy group than in the control group (p < 0.05). CONCLUSION: Endoscopic hydro-mastoidectomy enables more extensive bone resection within a shorter period.
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Colesteatoma da Orelha Média , Procedimentos Cirúrgicos Otológicos , Humanos , Mastoidectomia/métodos , Colesteatoma da Orelha Média/cirurgia , Resultado do Tratamento , Procedimentos Cirúrgicos Otológicos/métodos , Endoscopia/métodos , Processo Mastoide/cirurgia , Estudos RetrospectivosRESUMO
OBJECTIVES: Extending healthy life expectancy (HALE), defined as the average number of years that a person can expect to live in "full health" by taking into account years lived in less than full health due to disease and/or injury, is a common topic worldwide. This study aims to clarify the relationships between the Mediterranean diet score (MDS) and life expectancy (LE) and HALE globally using publicly available international data. SETTING: Analyses were conducted on 130 countries with populations of 1 million or more for which all data were available. Individual countries were scored from 0 to 9 to indicate adherence to the Mediterranean diet according to the MDS scoring method. The supply of vegetables, legumes, fruits and nuts, cereals, fish, and olive oil per 1,000 kcal per country was calculated based on the Food and Agriculture Organization Corporate Statistical Database, with a score of 1 for above the median and 0 for below. The same method was used to calculate scores of presumed detrimental components (meat and dairy), with consumption below the median given a value of 1, and consumption above the median given a value of 0. For ethanol, a score of 1 was given for 10g to 50 g of consumption. We investigated the cross-sectional associations between the MDS and LE and HALE at birth in 2009, and the longitudinal associations between the MDS in 2009 and LE and HALE between 2009 and 2019, controlling for covariates at baseline using linear mixed models. RESULTS: In the cross-sectional analysis, the MDS was significantly positively associated with LE (ß=0.906 [95% confidence interval, 0.065-1.747], p=0.037) and HALE (ß=0.875 [0.207-1.544], p=0.011) after controlling for all covariates. The longitudinal analysis also revealed significantly positive associations between the MDS and LE (0.621 [0.063-1.178], p=0.030) and HALE (0.694 [0.227-1.161], p=0.004) after controlling for all covariates. CONCLUSION: The present study, based on an analysis using 10 years of international data, showed that countries with a higher MDS showed a positive association with HALE.
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Dieta Mediterrânea , Animais , Estudos Transversais , Expectativa de Vida Saudável , Humanos , Expectativa de Vida , Modelos LinearesRESUMO
Myasthenia gravis (MG) is characterized by muscle weakness and fatigue caused by the presence of autoantibodies against the acetylcholine receptor (AChR) or the muscle-specific tyrosine kinase (MuSK). Activated T, B and plasma cells, as well as cytokines, play important roles in the production of pathogenic autoantibodies and the induction of inflammation at the neuromuscular junction in MG. Many studies have focused on the role of cytokines and lymphocytes in anti-AChR antibody-positive MG. Chronic inflammation mediated by T helper type 17 (Th17) cells, the promotion of autoantibody production from B cells and plasma cells by follicular Th (Tfh) cells and the activation of the immune response by dysfunction of regulatory T (Treg ) cells may contribute to the exacerbation of the MG pathogenesis. In fact, an increased number of Th17 cells and Tfh cells and dysfunction of Treg cells have been reported in patients with anti-AChR antibody-positive MG; moreover, the number of these cells was correlated with clinical parameters in patients with MG. Regarding cytokines, interleukin (IL)-17; a Th17-related cytokine, IL-21 (a Tfh-related cytokine), the B-cell-activating factor (BAFF; a B cell-related cytokine) and a proliferation-inducing ligand (APRIL; a B cell-related cytokine) have been reported to be up-regulated and associated with clinical parameters of MG. This review focuses on the current understanding of the involvement of cytokines and lymphocytes in the immunological pathogenesis of MG, which may lead to the development of novel therapies for this disease in the near future.
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Citocinas/imunologia , Miastenia Gravis/imunologia , Linfócitos T Reguladores/imunologia , Células Th17/imunologia , Animais , Autoanticorpos/imunologia , Linfócitos B/imunologia , Citocinas/metabolismo , Humanos , Miastenia Gravis/metabolismo , Receptores Proteína Tirosina Quinases/imunologia , Receptores Colinérgicos/imunologia , Células Th17/metabolismoRESUMO
Spin-orbit interaction and structure inversion asymmetry in combination with magnetic ordering is a promising route to novel materials with highly mobile spin-polarized carriers at the surface. Spin-resolved measurements of the photoemission current from the Si-terminated surface of the antiferromagnet TbRh_{2}Si_{2} and their analysis within an ab initio one-step theory unveil an unusual triple winding of the electron spin along the fourfold-symmetric constant energy contours of the surface states. A two-band k·p model is presented that yields the triple winding as a cubic Rashba effect. The curious in-plane spin-momentum locking is remarkably robust and remains intact across a paramagnetic-antiferromagnetic transition in spite of spin-orbit interaction on Rh atoms being considerably weaker than the out-of-plane exchange field due to the Tb 4f moments.
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Tissue reactions and stochastic effects after exposure to ionising radiation are variable between individuals but the factors and mechanisms governing individual responses are not well understood. Individual responses can be measured at different levels of biological organization and using different endpoints following varying doses of radiation, including: cancers, non-cancer diseases and mortality in the whole organism; normal tissue reactions after exposures; and, cellular endpoints such as chromosomal damage and molecular alterations. There is no doubt that many factors influence the responses of people to radiation to different degrees. In addition to the obvious general factors of radiation quality, dose, dose rate and the tissue (sub)volume irradiated, recognized and potential determining factors include age, sex, life style (e.g., smoking, diet, possibly body mass index), environmental factors, genetics and epigenetics, stochastic distribution of cellular events, and systemic comorbidities such as diabetes or viral infections. Genetic factors are commonly thought to be a substantial contributor to individual response to radiation. Apart from a small number of rare monogenic diseases such as ataxia telangiectasia, the inheritance of an abnormally responsive phenotype among a population of healthy individuals does not follow a classical Mendelian inheritance pattern. Rather it is considered to be a multi-factorial, complex trait.
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Radiação Ionizante , Animais , Humanos , Neoplasias Induzidas por Radiação/epidemiologia , Proteção Radiológica , Tolerância a RadiaçãoRESUMO
OBJECTIVES: We created a Traditional Japanese Diet Score (TJDS), and to clarify the relationship between TJDS and obesity, ischemic heart disease (IHD), and healthy life expectancy (HALE). DESIGN: Ecological study. SETTING: Food (g/day/capita) and energy (kcal/day/capita) supply was determined using the Food and Agriculture Organization of the United Nations Statistics Division database. The sum of characteristic traditional Japanese foods (beneficial food components in the Japanese diet: rice, fish, soybeans, vegetables, eggs, and seaweeds; food components rarely used in the Japanese diet: wheat, milk, and red meat) was divided as tertiles (beneficial food components: -1, 0, 1; rarely used food components: 1, 0, -1). Obesity rate was determined using the World Health Organization database. Incidence of IHD, HALE and smoking rate were determined using the Global Burden of Diseases, Injuries, and Risk Factors Study 2015 database. Gross domestic product per capita, percentage of population > 65 years old, and health expenditure were determined using the World Bank database. Education years were obtained from the United Nations Educational, Scientific and Cultural Organization Institute for Statistics. Associations between TJDS and obesity, IHD and HALE were examined in 132 countries with a population of 1 million or greater using a general linear model controlled for co-variables. RESULTS: TJDS was distributed from -6 to 7. TJDS was inversely correlated to obesity (ß±SE; -0.70±0.19, p<0.001), IHD (-19.4±4.3, p<0.001), and positively correlated to HALE (0.40±0.14, p<0.01). CONCLUSIONS: TJDS is a good indicator of a healthy diet, and applies to preventing obesity, IHD and extending HALE.
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Dieta Saudável/métodos , Nível de Saúde , Expectativa de Vida/tendências , Isquemia Miocárdica/etiologia , Obesidade/etiologia , Idoso , Animais , Feminino , Humanos , Incidência , Japão , Masculino , Fatores de RiscoRESUMO
BACKGROUND: In order to remove a cholesteatoma in the mastoid under transcanal endoscopic ear surgery, it is necessary to perform transcanal endoscopic mastoidectomy. Bone dust and blood, however, obscure the surgical field. A novel endoscopic hydro-mastoidectomy technique was developed, in which the operator performs the mastoidectomy 'underwater' using a lens cleaning system that provides saline perfusion in the surgical space. METHODS: A curved round coarse diamond bur is attached to an otological drill. A lens cleaning sheath is fitted to the endoscope. The surgeon controls the infusion of saline solution by stepping on a footswitch of the power console. RESULTS: Endoscopic hydro-mastoidectomy washes out bone dust and blood from the surgical field, improving the surgical view during mastoidectomy. Additionally, the operator can easily control the flow of saline perfusion. CONCLUSION: This technique provides a clear surgical view by washing out bone dust and blood from the surgical area. The setup for endoscopic hydro-mastoidectomy technique is easy and the operator needs only to buy sheaths if they already own the power console, as many otological and rhinological surgeons do.
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Mastoidectomia/métodos , Colesteatoma da Orelha Média/cirurgia , Humanos , Masculino , Mastoidectomia/instrumentação , Pessoa de Meia-Idade , Cirurgia Endoscópica por Orifício Natural/instrumentação , Cirurgia Endoscópica por Orifício Natural/métodosRESUMO
The aim of this study was to investigate the probability of facial nerve injury (FNI) in the treatment of condylar neck and subcondylar fractures (CN/SCFs) with percutaneous approaches and to identify factors predicting FNI. The data of 80 patients with 87 CN/SCFs were evaluated retrospectively. The primary outcome was FNI occurrence. The predictor variables were age, sex, aetiology, alcohol consumption, fracture site and pattern (dislocation or not), concomitant fractures, time interval to surgery, surgeon experience, plate type, and the dual classification of percutaneous approaches. The approaches were classified based on whether subcutaneous dissection traversed the marginal mandibular branch (MMB) deeply (deep group: submandibular and retroparotid approaches) or superficially (superficial group: transparotid, transmasseteric anteroparotid (TMAP), and high cervical-TMAP approaches). Twenty-two patients (27.5%) suffered FNI, of whom two in the deep group had permanent paralysis of the MMB. In the multivariate logistic regression model, deeply traversing surgery approaches (odds ratio 12.4, P=0.025) and the presence of a dislocated fracture (odds ratio 6.66, P=0.012) were associated with an increased risk of FNI. These results suggest that percutaneous approaches in the superficial group should be recommended for the treatment of CN/SCFs to reduce the risk of FNI.
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Traumatismos do Nervo Facial , Fraturas Mandibulares , Nervo Facial , Fixação Interna de Fraturas , Humanos , Côndilo Mandibular , Estudos RetrospectivosRESUMO
AIM: To optimise cross-sectional chest imaging usage by identifying frequency and risk factors associated with thoracic metastases in cervical cancer patients after initial definitive treatment. MATERIALS AND METHODS: This study, conducted during 2004-2015, examined 361 consecutive patients with histopathologically proven cervical carcinoma with at least 1 year of follow-up. Electronic medical records and all available imaging modes were used to record and assess patient and tumour characteristics and timing of thoracic metastases. Associations with these characteristics and thoracic metastases were assessed using univariate and multivariable Cox proportional hazards modelling. RESULTS: Of the 361 patients, 31 developed thoracic metastases. Multivariate regression results showed that adeno/adenosquamous carcinomas (hazard ratio [HR], 2.46; 95% confidence interval [CI], 1.06 to 5.72), other histology (HR, 5.61; 95% CI, 1.81 to 17.42), high International Federation of Gynaecology and Obstetrics (FIGO) stage (HR, 2.84; 95% CI, 1.09 to 7.37), and presence of initial intra-abdominal lymph node metastases (HR, 2.46; 95% CI, 1.02 to 5.90) were associated significantly and independently with thoracic metastases. The second analysis among the subgroup of surgical treatment identified intermediate-high risk classification of recurrence (HR, 5.12; 95% CI, 1.14 to 22.94), high FIGO stage (HR, 2.73; 95% CI, 1.05 to 7.13), and other histology (HR, 11.51; 95% CI, 3.66 to 36.19) as independent predictors of thoracic metastases. Two of the 361 and 2/313 patients with thoracic metastases who did not correspond to the conditions above were in the respective evaluation groups. CONCLUSION: Assessment of negative prognostic factors for thoracic metastases might contribute to reduced need for chest cross-sectional chest computed tomography examinations.
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Diagnóstico por Imagem/métodos , Metástase Linfática/diagnóstico por imagem , Neoplasias Torácicas/diagnóstico por imagem , Neoplasias Torácicas/secundário , Neoplasias do Colo do Útero/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Fatores de RiscoRESUMO
A history of hypertension is a known risk factor for delirium in patients in intensive care units, but the effect of antihypertensive agents on delirium development is unclear. Nicardipine, a calcium channel blocker, is widely used in ICU as a treatment agent for hypertensive emergency. This study investigated the relationship between the administration of nicardipine hydrochloride and delirium development in patients under mechanical ventilation. We conducted a medical chart review of 103 patients, who were divided into two groups according to the use of nicardipine hydrochloride. The prevalence of delirium was compared with respect to factors such as age, sex, laboratory data, and medical history, by multivariate analysis. 21 patients (20.4 %) were treated with nicardipine hydrochloride in 103 patients. The treatment and non-treatment groups differed significantly in age (72 vs. 65 years) and history of high blood pressure (57% vs. 11%). Multivariate analysis revealed that patients in the treatment group developed delirium significantly less often than those in the non-treatment group (19% vs. 48%). These results suggested that treatment of high blood pressure with nicardipine hydrochloride is a possible method for preventing the development of delirium.
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Delírio/epidemiologia , Hipertensão/tratamento farmacológico , Nicardipino/administração & dosagem , Respiração Artificial , Adulto , Idoso , Idoso de 80 Anos ou mais , Anti-Hipertensivos/administração & dosagem , Anti-Hipertensivos/farmacologia , Bloqueadores dos Canais de Cálcio/administração & dosagem , Bloqueadores dos Canais de Cálcio/farmacologia , Delírio/etiologia , Delírio/prevenção & controle , Feminino , Humanos , Hipertensão/complicações , Unidades de Terapia Intensiva , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Nicardipino/farmacologia , Prevalência , Estudos Retrospectivos , Fatores de RiscoRESUMO
OBJECTIVES: This study describes trends in dietary diversity and food intake over 12 years according to age at first participation in the study. DESIGN: Prospective cohort study. SETTING: The National Institute for Longevity Sciences - Longitudinal Study of Aging, a community-based study. PARTICIPANTS: Participants included 922 men and 879 women who participated in the first study-wave (age, 40-79 years) and also participated in at least one study-wave from the second to seventh study-wave. Study-waves were conducted biennially. MEASUREMENTS: Dietary intake was calculated from 3-day dietary records with photographs. Dietary diversity was determined using the Quantitative Index for Dietary Diversity based on food intake. A mixed-effects model was used to estimate linear changes in dietary diversity and food intake over 12 years according to age at first study-wave. RESULTS: Mean (standard deviation (SD)) follow-up time and number of study-wave visits were 9.5 (3.7) years and 5.4 (1.8), respectively. Mean (SD, range) dietary diversity score was 0.86 (0.06, 0.52-0.96) in men and 0.88 (0.04, 0.66-0.96) in women, respectively. Fixed effects for interactions of age and time with dietary diversity score were statistically significant (p<0.05). The slope of dietary diversity among men aged 40 to 55 years increased (40-year-old slope = 0.00093/year, p<0.01; 55-year-old slope = 0.00035/year, p=0.04), with a decreasing trend started at 65 years old, although this trend was not significant (65-year-old slope = -0.00003/year, p=0.88; 79-year-old slope = -0.00057/year, p=0.21). The slope of dietary diversity among women aged 40 to 44 years increased (40-year-old slope = 0.00053/year, p=0.02; 44-year-old slope = 0.00038/year, p=0.04), whereas the slope of dietary diversity among women aged 63 to 79 years decreased (63-year-old slope = -0.00033/year, p=0.03; 79-year-old slope = -0.00092/year, p<0.001). Fruit, milk and dairy intake decreased in men around their 60s; milk and dairy intake decreased in women around their 50s; and beans and fruit intake decreased in women from their 70s. CONCLUSION: Twelve-year longitudinal data showed dietary diversity declined in women in their 60s. In terms of food intake, fruit, milk and dairy intake decreased in both sexes in their 50s and 60s; such declines would lower dietary diversity.
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Envelhecimento/psicologia , Dieta/métodos , Preferências Alimentares/psicologia , Estado Nutricional/fisiologia , Adulto , Idoso , Animais , Registros de Dieta , Feminino , Frutas , Humanos , Vida Independente , Japão , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Leite , Estudos ProspectivosRESUMO
We assessed the health state utility value (HSUV) reductions associated with vertebral fractures using data collected in the Japanese Osteoporosis Intervention Trial-03 (JOINT-03). Our analysis revealed that assessment of HSUVs after morphometric vertebral fracture is important to capture the burden of vertebral fractures. INTRODUCTION: Evaluation of the HSUV after fracture is important to calculate the quality-adjusted life years (QALYs) of osteoporosis patients, which is essential information in the context of health economic evaluation. METHODS: JOINT-03 study patients were aged ≥65 years and treated with risedronate and vitamin K2 or risedronate alone. Radiographic information and patient-reported outcomes measured by EQ-5D and a visual analogue scale (VAS) were assessed at registration and followed up after 6, 12, and 24 months. According to differences among the dates of these assessments and the radiographic information, we classified the follow-up HSUVs calculated based on EQ-5D results into before or after fracture categories regardless of clinical symptoms. RESULTS: Among 2922 follow-up HSUVs, 201 HSUVs were categorized as HSUVs that were observed after incident vertebral fractures on X-ray films. The median time from the detection of an incident vertebral fracture until the EQ-5D assessment was 53 days (25th percentile, 0 day; 75th percentile, 357 days). The impact of incident vertebral fractures on HSUVs was quantified as -0.03. Among the five health profile domains on the EQ-5D, an incident vertebral fracture had significant effects on anxiety/depression, self-care, and usual activities. CONCLUSIONS: The results suggest that incident morphometric vertebral fracture was associated with impairment of the HSUV for patients with osteoporosis not only immediately but also several months after the fracture.
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Osteoporose Pós-Menopausa/reabilitação , Fraturas por Osteoporose/reabilitação , Fraturas da Coluna Vertebral/reabilitação , Atividades Cotidianas , Idoso , Idoso de 80 Anos ou mais , Conservadores da Densidade Óssea/uso terapêutico , Quimioterapia Combinada , Feminino , Humanos , Japão/epidemiologia , Osteoporose Pós-Menopausa/complicações , Osteoporose Pós-Menopausa/tratamento farmacológico , Osteoporose Pós-Menopausa/epidemiologia , Fraturas por Osteoporose/complicações , Fraturas por Osteoporose/epidemiologia , Dor/epidemiologia , Dor/etiologia , Medição da Dor/métodos , Medidas de Resultados Relatados pelo Paciente , Anos de Vida Ajustados por Qualidade de Vida , Ácido Risedrônico/uso terapêutico , Fraturas da Coluna Vertebral/complicações , Fraturas da Coluna Vertebral/epidemiologia , Vitamina K 2/uso terapêuticoRESUMO
AIM: To clarify the natural course of prediabetes and develop predictive models for conversion to diabetes. METHODS: A retrospective longitudinal study of 2105 adults with prediabetes was carried out with a mean observation period of 4.7years. Models were developed using multivariate logistic regression analysis and verified by 10-fold cross-validation. The relationship between [final BMI minus baseline BMI] (δBMI) and incident diabetes was analyzed post hoc by comparing the diabetes conversion rate for low (< -0.31kg/m2) and high δBMI (≥ -0.31kg/m2) subjects after matching the two groups for the covariates. RESULTS: Diabetes developed in 252 (2.5%/year), and positive family history, male sex, higher systolic blood pressure, plasma glucose (fasting and 1h- and 2h-values during 75g OGTT), hemoglobin A1c (HbA1c) and alanine aminotransferase were significant, independent predictors for the conversion. By using a risk score (RS) that took account of all these variables, incident diabetes was predicted with an area under the ROC curve (95% CI) of 0.80 (0.70-0.87) and a specificity of prediction of 61.8% at 80% sensitivity. On division of the participants into high- (n=248), intermediate- (n=336) and low-risk (n=1521) populations, the conversion rates were 40.1%, 18.5% and 5.9%, respectively. The conversion rate was lower in subjects with low than high δBMI (9.2% vs 14.4%, p=0.003). CONCLUSIONS: Prediabetes conversion to diabetes could be predicted with accuracy, and weight reduction during the observation was associated with lowered conversion rate.
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Diabetes Mellitus Tipo 2/etiologia , Modelos Biológicos , Sobrepeso/fisiopatologia , Estado Pré-Diabético/fisiopatologia , Povo Asiático , Índice de Massa Corporal , Estudos de Coortes , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/epidemiologia , Diabetes Mellitus Tipo 2/etnologia , Progressão da Doença , Feminino , Hospitais Urbanos , Humanos , Incidência , Japão/epidemiologia , Estudos Longitudinais , Masculino , Programas de Rastreamento , Pessoa de Meia-Idade , Sobrepeso/complicações , Sobrepeso/diagnóstico , Sobrepeso/etnologia , Estado Pré-Diabético/complicações , Estado Pré-Diabético/diagnóstico , Estado Pré-Diabético/etnologia , Prognóstico , Estudos Retrospectivos , Fatores de Risco , Sensibilidade e Especificidade , Fatores SexuaisRESUMO
The mechanism of the two-phase Brust-Schiffrin synthesis of alkane thiol protected metal nanoparticles is known to be highly sensitive to the precursor species and reactant conditions. In this work X-ray absorption spectroscopy is used in conjunction with liquid/liquid electrochemistry to highlight the significance of Br- in the reaction mechanism. The species [AuBr4]- is shown to be a preferable precursor in the Brust-Schiffrin method as it is more resistant to the formation of Au(i) thiolate species than [AuCl4]-. Previous literature has demonstrated that avoidance of the Au(i) thiolate is critical to achieving a good yield of nanoparticles, as [Au(i)X2]- species are more readily reduced by NaBH4. We propose that the observed behavior of [AuBr4]- species described herein explains the discrepancies in reported behavior present in the literature to date. This new mechanistic understanding should enable nanoparticle synthesis with a higher yield and reduce particle size polydispersity.
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Temporally and spatially resolved soft x-ray and end-loss-electron analyses of the electron cyclotron heated plasmas are carried out by using a semiconductor detector array and an electrostatic energy analyzer in the GAMMA 10 tandem mirror. The flux and the energy spectrum of the end loss electrons are measured by a multi-grid energy analyzer. Recently, the electron cyclotron heating power modulation experiments have been started in order to generate and control the high heat flux and to make the edge localized mode-like intermittent heat load pattern for the divertor simulation studies by the use of these detectors for electron properties.
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We have developed an analysis method to improve the accuracies of electron temperature measurement by employing a fitting technique for the raw Thomson scattering (TS) signals. Least square fitting of the raw TS signals enabled reduction of the error in the electron temperature measurement. We applied the analysis method to a multi-pass (MP) TS system. Because the interval between the MPTS signals is very short, it is difficult to separately analyze each Thomson scattering signal intensity by using the raw signals. We used the fitting method to obtain the original TS scattering signals from the measured raw MPTS signals to obtain the electron temperatures in each pass.
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The enhancement of functionality of perovskite ferroelectrics by local structure is one of current interests. By the Li-doping to KTa(1-x)NbxO3 (KTN), the large piezoelectric and electro-optic effects were reported. In order to give new insights into the mechanism of doping, the microscopic origin of the Fano resonance induced by the local structure was investigated in 5%Li-doped KTN single crystals by Raman scattering. The coupling between the continuum states and the transverse optical phonon near 196 cm(-1) (Slater mode) caused a Fano resonance. In the vicinity of the cubic-tetragonal phase transition temperature, TC-T = 31 °C, the almost disappearance of the Fano resonance and the remarkable change of the central peak (CP) intensity were observed upon heating. The local symmetry of the polar nanoregions (PNRs), which was responsible for the symmetry breaking in the cubic phase, was determined to E(x, y) symmetry by the angular dependence of Raman scattering. The electric field induced the significant change in the intensity of both CP and Fano resonance. From these experimental results, it is concluded that the origin of the Fano resonance in Li-doped KTN crystals is the coupling between polarization fluctuations of PNRs and the Slater mode, both belong to the E(x, y) symmetry.