366 research outputs found

    Statin use reduces cardiovascular events and all-cause mortality amongst Chinese patients with type 2 diabetes mellitus: a 5-year cohort study

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    Saturated electric field effect at semi-insulating GaAs-metal junctions studied with a low energy positron beam

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    The interfacial electric field established under different reverse bias conditions in Au and Ni on semi-insulating GaAs junctions has been studied by means of a low energy positron beam. The technique used is that of monitoring the positron drift to the interface through changes in the annihilation radiation lineshape as a function of incident positron beam energy at different reverse biases The data show a small but clear electric field drift of positrons towards the interface that increases more rapidly at low voltages (less than 50 V) which at higher biases tends towards saturation This confirmation of electric field saturation adds further weight to the picture of an electric field enhanced electron capture cross section for the ionized EL2 defect. Electric field values extracted from the data are compared with results from other techniques and suggest that enhanced electron capture is already occurring at the relatively low built-in fields (∼1 kV cm-1) found at the unbiased junction, with a rapid increase of EL2+ neutralization occurring for biases above 10 V. At still higher fields ∼10 kV cm-1 (biases>50 V), there appears to be an additional threshold for more complete EL2+ neutralization adjacent to the contact. The present study clearly demonstrates the often overlooked necessity of catering for built-in electric fields in positron diffusivity studies of III-V semiconductors where surface midgap Fermi-level pinning is common. © 1997 American Institute of Physics.published_or_final_versio

    Association of Hemoglobin A1c Levels With Cardiovascular Disease and Mortality in Chinese Patients With Diabetes

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    LettersAmong diabetic patients, hemoglobin A1c (HbA1c) is an important indicator of glycemic control and, together with blood pressure and cholesterol, is an indicator for risk of complications, including cardiovascular disease (CVD) and mortality. At present, there is no universal consensus on the optimal HbA1c level. Despite this, most international guidelines include a recommended HbA1c target range or level as a treatment goal. Several studies have identified a J-shaped curvilinear relationship between HbA1c and CVD incidence and all-cause mortality, but such a relationship has not yet been confirmed in a Chinese population. There are substantial differences in disease risks across racial and ethnic groups due to genetic and environmental factors including life-style and health behaviors, and thus, previous results from Western studies may not be transferable to a Chinese population. We sought to examine the association among mean HbA1c, CVD events, and mortality among Chinese primary care patients with type 2 diabetes mellitus (T2DM) in Hong Kong.postprin

    Effect of metformin monotherapy on cardiovascular diseases and mortality: a retrospective cohort study on Chinese type 2 diabetes mellitus patients

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    Background: Many factors influence whether the first-line oral anti-diabetic drug, metformin, should be initiated to a patient with type 2 diabetes mellitus (T2DM) early in the course of management in addition to lifestyle modifications. This study aims to evaluate the net effects of metformin monotherapy (MM) on the all-cause mortality and cardiovascular disease (CVD) events. Methods: A retrospective 5-year follow-up cohort study was conducted on Chinese adult patients with T2DM and without any CVD history under public primary care. Cox proportional hazard regressions were performed to compare the risk of all-cause mortality and CVD events (CHD, stroke, heart failure) between patients receiving lifestyle modifications plus MM (MM groups) and those with lifestyle modifications alone (control groups). Results: 3400 pairs of matched patients were compared. MM group had an incidence rate of 7.5 deaths and 11.3 CVD events per 1000 person-years during a median follow-up period of 62.5 months whereas control group had 11.1 deaths and 16.3 per 1000 person-years during a median follow-up period of 43.5–44.5 months. MM group showed a 29.5 and 30–35 % risk reduction of all-cause mortality and CVD events (except heart failure) than control group (P < 0.001). MM group was more prone to progress to chronic kidney disease but this was not statistically significant. Conclusions: Type 2 diabetic patients who were started on metformin monotherapy showed improvement in many of the clinical parameters and a reduction in all-cause mortality and CVD events than lifestyle modifications alone. If there is no contraindication and if tolerated, diabetic patients should be prescribed with metformin early in the course of the diabetic management to minimize their risk of having the cardiovascular events and mortality in the long run.published_or_final_versio

    Electric-field distribution in Au–semi-insulating GaAs contact investigated by positron-lifetime technique

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    Positron-lifetime spectroscopy has been used to investigate the electric-field distribution occurring at the Au–semi-insulating GaAs interface. Positrons implanted from a 22Na source and drifted back to the interface are detected through their characteristic lifetime at interface traps. The relative intensity of this fraction of interface-trapped positrons reveals that the field strength in the depletion region saturates at applied biases above 50 V, an observation that cannot be reconciled with a simple depletion approximation model. The data, are, however, shown to be fully consistent with recent direct electric-field measurements and the theoretical model proposed by McGregor et al. [J. Appl. Phys. 75, 7910 (1994)] of an enhanced EL2+ electron-capture cross section above a critical electric field that causes a dramatic reduction of the depletion region’s net charge density. Two theoretically derived electric field profiles, together with an experimentally based profile, are used to estimate a positron mobility of ∼95±35 cm2 V-1 s-1 under the saturation field. This value is higher than previous experiments would suggest, and reasons for this effect are discussed.published_or_final_versio

    Effects of the Multidisciplinary Risk Assessment and Management Program for Patients with Diabetes Mellitus (RAMP-DM) on biomedical outcomes, observed cardiovascular events and cardiovascular risks in primary care: a longitudinal comparative study

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    Background To assess whether the Multidisciplinary Risk Assessment and Management Program for Patients with Diabetes Mellitus (RAMP-DM) led to improvements in biomedical outcomes, observed cardiovascular events and predicted cardiovascular risks after 12-month intervention in the primary care setting. Methods A random sample of 1,248 people with diabetes enrolled to RAMP-DM for at least 12-months was selected and 1,248 people with diabetes under the usual primary care were matched by age, sex, and HbA1c level at baseline as the usual care group. Biomedical and cardiovascular outcomes were measured at baseline and at 12-month after the enrollment. Difference-in-differences approach was employed to measure the effect of RAMP-DM on the changes in biomedical outcomes, proportion of subjects reaching treatment targets, observed and predicted cardiovascular risks. Results Compared to the usual care group, RAMP-DM group had lower cardiovascular events incidence (1.21% vs 2.89%, P=0.003), and net decrease in HbA1c (-0.20%, P<0.01), SBP (-3.62 mmHg, P<0.01) and 10-year cardiovascular disease (CVD) risks (total CVD risk, -2.06%, P<0.01; coronary heart disease (CHD) risk, -1.43%, P<0.01; stroke risk, ?0.71%, P<0.01). The RAMP-DM subjects witnessed significant rises in the proportion of reaching treatment targets of HbA1c, and SBP/DBP. After adjusting for confounding variables, the significance remained for HbA1c, predicted CHD and stroke risks. Conclusions The RAMP-DM resulted in greater improvements in HbA1c and reduction in observed and predicted cardiovascular risks at 12-months follow-up, which indicated a risk-stratification multidisciplinary intervention was an effective strategy for managing Chinese people with diabetes in the primary care setting. Trial registryClinicalTrials.gov, NCT02034695published_or_final_versio
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