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In situ ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) combined with resistivity measurement was performed for a Pt thin-film H2 gas sensor. We experimentally demonstrate that the chemical state of the Pt surface changes under working conditions, and it directly links to the sensing performance. Moreover, the operating principle is discussed at the atomic scale. [ABSTRACT FROM AUTHOR]

H2 and NH3 detection with low power consumption was demonstrated by integrated chemiresistive Pt and PtRh nanosheet sensors on glass substrates. The self-heating effects realized low power and local heating of metal nanosheet sensors, enabling the integration of sensors with different operating temperatures. Based on different resistance changes in Pt and PtRh nanosheets toward H2 and NH3, the concentration of each gas was detected from a gas mixture by consuming around 1-mW power. For decreasing the power consumption and further integration of sensors, sensor scaling and pulsed operations were numerically and experimentally studied. In addition to good connectivity of metal nanosheet sensors to large-scale integration (LSI) circuits, improvements of the power consumption by sensor scaling were proven. The pulsed operations required for integrated sensor arrays maintained a sensor response, or a resistance change, of approximately 60%, even when the power consumption was reduced by 20%. [ABSTRACT FROM AUTHOR]

Hydrogen is an important biomarker for the human digestive system. However, accurate detection of ppm-level hydrogen in breath is difficult due to the competing detection of high concentration water. We fabricated Pt thin films that respond to hydrogen in air at concentrations as low as 500 ppb. In both dry and humid air, these films have almost identical response to hydrogen, i.e., their resistance decreases linearly with increasing hydrogen concentration regardless of relative humidity. Even at high relative humidity, these Pt thin films can detect ppm-level hydrogen. Furthermore, it was strongly suggested that these films can be applied to low-level hydrogen in the air expired by a healthy human. Based on the chemical kinetics, namely the adsorption and desorption of hydrogen and oxygen, the sensor response is quantitatively described by relating the hydrogen surface coverage to the magnitude of electron scattering at the Pt surface. The proposed model successfully reproduces the effects of hydrogen concentration and time on the sensor response, particularly at hydrogen concentrations below 20 ppm. Based on this model, these Pt thin film sensors have the potential to detect 1 ppm hydrogen in expired air within 30 s. [ABSTRACT FROM AUTHOR]

Background: Socio-economic status has been associated with diabetes in cross-sectional studies. This study aimed to evaluate associations of household income and wealth with both prevalent and incident diabetes among older adults in the UK. It also evaluated the association between obesity and socio-economic status. Methods: A cohort of people aged ≥50 years was selected from the English Longitudinal Study of Ageing. The relation of prevalent and incident self-reported physician diagnosed diabetes to household income and wealth was evaluated in logistic regression models adjusting for education, social class, housing tenure, age, ethnicity, marital status, body mass index (BMI), smoking, alcohol use and physical activity stratified by sex. The relation of prevalent obesity to household income and wealth was also evaluated using logistic regression models. Results: There were 9053 participants (4021 men and 5032 women) including 721 (8.0%) with diabetes at baseline. Among 8332 participants initially free from diabetes, 246 (3.0%) were diagnosed with diabetes during ∼4 years follow-up. The adjusted odds ratio for prevalent diabetes in the lowest quintile of wealth compared with the highest was 1.56 for men and 2.08 for women. Incident diabetes was associated with lower wealth (P for trend 0.05 for men and 0.004 for women) after adjusting for socio-economic and demographic factors, but attenuated after further adjustment for lifestyle and BMI. Prevalent obesity was significantly associated with lower wealth in women but not in men. Conclusion: Lower wealth, but not income, may be associated with prevalent and incident diabetes among older adults in UK. [ABSTRACT FROM AUTHOR]

The temperature dependence of the mobility of the two-dimensional electron gas (2DEG) in a silicon quantum well strained by Si0.7Ge0.3 relaxed buffer layer is determined precisely by a mobility spectrum analysis. The 2DEG mobility is 2780 cm2/V s at room temperature and, upon cooling, increases continuously to reach μ2DEG=7.4×104cm2/Vs at 7 K. A back gate installed on the sample changes the 2DEG concentration n successfully to establish μ2DEG∝n1.4 at the constant temperature T=10K, implying that the scattering at such low temperature is limited solely by the remote ionized impurity scattering. Based on this finding, theoretical analysis of the temperature dependence of μ2DEG is performed based on the relaxation time approximation using 2DEG wavefunctions and subband structures determined self-consistently and including three major scatterings; by intravalley acoustic phonons, intervalley g-processes of longitudinal optical (LO) phonons, and remote ionized impurities. The calculation included only three fitting parameters, the shear deformation potential (Ξu=9.5eV), LO phonon deformation potential for g-process scattering (D0=9.0×108eV/cm), and sheet density of remote ionized impurities that have been determined by quantitative comparison with our experimental results. The temperature dependence of μ2DEG calculated theoretically show excellent agreement with experimentally determined μ2DEG. [ABSTRACT FROM AUTHOR]

Aims/Introduction Recently, the prevalence of lifestyle-related disease has increased, and its associated medical costs have become considerable. Although walking is thought to prevent lifestyle-related disease, few studies have evaluated its effect on medical costs in Japanese subjects. We aimed at evaluating the effect of walking on medical costs by simulation mainly focusing on diabetes in the Japanese population. Materials and Methods A Markov model focusing on diabetes was constructed. As complications of diabetes, 'dialysis', 'ischemic heart disease' and 'stroke' were included. The model has four states: 'non-diabetes', 'diabetes', 'dialysis' and 'dead', and 'ischemic heart disease' and 'stroke' were included as events that occurred in each state. The effect of walking was included as changing the rate of transition and incident rates of events. Results After 10 years, the numbers of subjects with diabetes were 4.3 and 7.3% lower for daily increase of 3,000 and 5,000 steps, respectively. The numbers of cases of ischemic heart disease and stroke also decreased. Lower medical costs were also seen according to the daily increase in steps. In 10 years, the total medical costs were 5.2 and 8.4% lower for 3,000 and 5,000 steps increase, respectively. The cost reduction associated with a daily increase of 3,000 steps walked was calculated as ¥0.00146 for each step. Conclusions Walking is one of the most common and accessible forms of exercises. The present results suggested that walking reduced the medical costs associated with lifestyle-related disease, which will have a large impact on health policy. [ABSTRACT FROM AUTHOR]

Immobilization of a catalytically active metal complex onto an electrode surface in highly dispersed form is crucial to assure high catalytic activity observed in solution. In this report, mononuclear CoII chlorin complexes were successfully immobilized on a conductive metal-oxide electrode by using electron conducting molecular wires comprising phenylene–ethynylene-based π-conjugation covered by a linked permethylated α-cyclodextrin to enhance electrocatalysis for selective two electron reduction of molecular oxygen to hydrogen peroxide. First, the rotaxane-encapsulation effect of the molecular wire on electron transfer was examined by the comparison of electrochemical behaviors of ferrocene (Fc) molecules immobilized on an ITO substrate using the molecular wires with or without rotaxane encapsulation. Then, electrodes were modified with metalloporphyrinoids, i.e., RhIII(OEP)Cl (OEP = 2,3,7,8,12,13,17,18-octaethylporphyrin) and CoII chlorin through coordination with the molecular wires with pyridine moieties at the end. The electrocatalytic O 2 reduction was performed with CoII chlorin immobilized on an electron-conductive metal-oxide substrate by molecular wires. The turnover frequency for H 2 O 2 production using the CoII chlorin coordinated by molecular wires with rotaxane encapsulation was 331 ± 75, which is significantly higher than that of 82 ± 8 obtained for CoII chlorin immobilized by that without rotaxane encapsulation. These results clearly indicate that the molecular wires with rotaxane encapsulation are beneficial for CoII chlorin complexes to exhibit high electrocatalytic activity and selectivity to H 2 O 2. [Display omitted] • Efficient electron transfer from metal-oxide electrodes to a metal complex was realized by using molecular wires. • Molecular wires with rotaxane encapsulation was suitable for efficient electron transfer and maintaining monomeric structure. • Molecular wires with pyridyl group at the end can coordinate to various metal complexes including porphyrinoids. • Molecular wires enable the cobalt chlorine complex to maintain monomeric structure suitable for H 2 O 2 production. [ABSTRACT FROM AUTHOR]