Dopant-induced crossover from 1D to 3D charge transport in conjugated polymers

The interplay between inter- and intra-chain charge transport in bulk polythiophene in the hopping regime has been clarified by studying the conductivity as a function of frequency (up to 3 THz), temperature and doping level. We present a model which quantitatively explains the observed crossover from quasi-one-dimensional transport to three-dimensional hopping conduction with increasing doping level. At high frequencies the conductivity is dominated by charge transport on one-dimensional conducting chains.Comment: 4 pages, 2 figure

Localized and Delocalized Charge Transport in Single-Wall Carbon-Nanotube Mats

We measured the complex dielectric constant in mats of single-wall carbon-nanotubes between 2.7 K and 300 K up to 0.5 THz. The data are well understood in a Drude approach with a negligible temperature dependence of the plasma frequency (omega_p) and scattering time (tau) with an additional contribution of localized charges. The dielectric properties resemble those of the best ''metallic'' polypyrroles and polyanilines. The absence of metallic islands makes the mats a relevant piece in the puzzle of the interpretation of tau and omega_p in these polymers.Comment: 4 pages including 4 figure

Microvascular complications at time of diagnosis of type 2 diabetes are similar among diabetic patients detected by targeted screening and patients newly diagnosed in general practice - The Hoorn Screening Study

OBJECTIVE - To investigate whether screening-detected diabetic patients differ from diabetic patients newly diagnosed in general practice with regard to the presence of microvascular complications. RESEARCH AND DESIGN METHODS - Diabetic patients, identified by a population-based targeted screening procedure consisting of a screening questionnaire and a fasting capillary whole-blood glucose measurement followed by diagnostic testing, were compared with patients newly diagnosed with diabetes in general practice. Retinopathy was assessed with fundus photography, impaired foot sensitivity was assessed with Semmes-Weinstein monofilaments, and the presence of microalbuminuria was measured by means of the albumin-to creatinine ratio (ACR). RESULTS - A total of 195 screening-detected type 2 diabetic patients and 60 patients newly diagnosed in general practice participated in the medical examination. The prevalence of retinopathy was higher in screening-detected type 2 diabetic patients than in patients newly diagnosed in general practice, but not significantly higher. The prevalence of retinopathy was 7.6% (95% CI 4.6-12.4) in screening-detected type 2 diabetic patients and 1.9% (0.3-9.8) in patients newly diagnosed in general practice. The prevalence of impaired foot sensitivity was similar in both groups, 48.1% (40.9-55.3) and 48.3% (36.2-60.7), respectively. The ACR was 0.61 (interquariile range 0.41-1.50) in screening-detected type 2 diabetic patients and 0.99 (0.53-2.49) in patients newly diagnosed in general practice. The difference in prevalence of microalbuminuria was not statistically significant. The prevalence of microalbuminuria was 17.2% (95% CI 12.5-23.2) and 26.7% (17.1-39.0) in screening-detected type 2 diabetic patients and patients newly diagnosed in general practice, respectively. CONCLUSIONS - Targeted screening for type 2 diabetes (with a screening questionnaire as a first step) resulted in the identification of previously undiagnosed diabetic patients with a considerable prevalence of microvascular complications

Diagnostic accuracy of depression questionnaires in adult patients with diabetes: a systematic review and meta-analysis

Importance Comorbid depression is common among patients with diabetes and has severe health consequences, but often remains unrecognized. Several questionnaires are used to screen for depression. A systematic review and meta-analysis regarding the diagnostic accuracy of depression questionnaires in adults with diabetes is unavailable. Objective To conduct a systematic review and meta-analysis to evaluate the diagnostic accuracy of depression questionnaires in adults with type 1 or type 2 diabetes. Data sources PubMed, Embase and PsycINFO were searched from inception to 28 February 2018. Study selection Studies were included when the diagnostic accuracy of depression questionnaires was assessed in a diabetes population and the reference standard was a clinical interview. Data extraction and synthesis Data extraction was performed by one reviewer and checked by another. Two reviewers independently conducted the quality assessment (QUADAS-2). Diagnostic accuracy was pooled in bivariate random effects models. This study is reported according to PRISMA-DTA and is registered with PROSPERO (CRD42018092950). Main Outcome(s) and measure(s) Diagnostic accuracy, expressed as sensitivity and specificity, of depression questionnaires in an adult diabetes population. Results A total 6,097 peer-reviewed articles were screened. Twenty-one studies (N= 5,703 patients) met the inclusion criteria for the systematic review. Twelve different depression questionnaires were identified, of which the CES-D (n=6 studies) and PHQ-9 (n=7 studies) were the most frequently evaluated. Risk of bias was unclear for multiple domains in the majority of studies. In the meta-analyses, five (N= 1,228) studies of the CES-D (≥16), five (N= 1,642) of the PHQ-9 (≥10) and four (N=822) of the algorithm of the PHQ-9 were included in the pooled analysis. The CES-D (≥16) had a pooled sensitivity of 85.0% (95%CI, 71.3-92.8%) and a specificity of 71.6% (95%CI, 62.5-79.2%); the PHQ-9 (≥10) had a sensitivity of 81.5% (95%CI, 57.1-93.5%) and a specificity of 79.7% (95%CI, 62.1-90.4%). The algorithm for the PHQ-9 had a sensitivity of 60.9% (95%CI, 52.3-50 90.8%) and a specificity of 64.0% (95%CI, 53.0-93.9%). Conclusions and relevance This review indicates that the CES-D had the highest sensitivity, whereas the PHQ-9 had the highest specificity, although confidence intervals were wide and overlapping. The algorithm for the PHQ-9 had the lowest sensitivity and specificity. Given the variance in results and suboptimal reporting of studies, further high quality studies are needed to confirm the diagnostic accuracy of these depression questionnaires in patients with diabetes

Diabetic patients detected by population-based stepwise screening already have a diabetic cardiovascular risk profile

OBJECTIVE - To describe a population-based two-step screening procedure for type 2 diabetes and to study the cardiovascular risk profile of the patients identified by the screening. RESEARCH DESIGN AND METHODS - The first step of the screening procedure consisted of the Symptom Risk Questionnaire (SRQ), and the second step was a fasting capillary glucose measurement. In subjects with an SRQ score of >6 and a capillary glucose level of >5.5 mmol/l, an oral glucose tolerance test was performed. RESULTS - A total of 11,679 inhabitants of the West-Friesland region of the Netherlands, aged 50-75 years, were invited. Of the inhabitants, 9,169 (78%) responded, and, of those, 417 had previously diagnosed diabetes. The SRQ score was calculated for 7,736 participants, and 3,301 of those had a score of >6. A total of 2,885 subjects (87.3%) attended for capillary glucose measurement. Diagnostic testing was carried out in 509 participants, and we identified 217 diabetic patients. In these patients detected by screening, mean Hb

Screening for type 2 diabetes is feasible, acceptable, but associated with increased short-term anxiety: A randomised controlled trial in British general practice

<p>Abstract</p> <p>Background</p> <p>To assess the feasibility and uptake of a diabetes screening programme; to examine the effects of invitation to diabetes screening on anxiety, self-rated health and illness perceptions.</p> <p>Methods</p> <p>Randomised controlled trial in two general practices in Cambridgeshire. Individuals aged 40–69 without known diabetes were identified as being at high risk of having undiagnosed type 2 diabetes using patient records and a validated risk score (n = 1,280). 355 individuals were randomised in a 2 to 1 ratio into non-invited (n = 238) and invited (n = 116) groups. A stepwise screening programme confirmed the presence or absence of diabetes. Six weeks after the last contact (either test or invitation), a questionnaire was sent to all participants, including non-attenders and those who were not originally invited. Outcome measures included attendance, anxiety (short-form Spielberger State Anxiety Inventory-STAI), self-rated health and diabetes illness perceptions.</p> <p>Results</p> <p>95 people (82% of those invited) attended for the initial capillary blood test. Six individuals were diagnosed with diabetes. Invited participants were more anxious than those not invited (37.6 vs. 34.1 STAI, p-value = 0.015), and those diagnosed with diabetes were considerably more anxious than those classified free of diabetes (46.7 vs. 37.0 STAI, p-value = 0.031). Non-attenders had a higher mean treatment control sub-scale (3.87 vs. 3.56, p-value = 0.016) and a lower mean emotional representation sub-scale (1.81 vs. 2.68, p-value = 0.001) than attenders. No differences in the other five illness perception sub-scales or self-rated health were found.</p> <p>Conclusion</p> <p>Screening for type 2 diabetes in primary care is feasible but may be associated with higher levels of short-term anxiety among invited compared with non-invited participants.</p> <p>Trial registration</p> <p>ISRCTN99175498</p

Cost-effectiveness of a stepped care program to prevent depression among primary care patients with diabetes mellitus type 2 and/or coronary heart disease and subthreshold depression in comparison with usual care

Background Patients with diabetes mellitus type 2 (DM2) and/or coronary heart disease (CHD) are at high risk to develop major depression. Preventing incident major depression may be an important tool in reducing the personal and societal burden of depression. The aim of the current study was to assess the cost-effectiveness of a stepped care program to prevent major depression (Step-Dep) in diabetes mellitus type 2 and/or coronary heart disease patients with subthreshold depression in comparison with usual care. Methods An economic evaluation with 12 months follow-up was conducted alongside a pragmatic cluster-randomized controlled trial from a societal perspective. Participants received care as usual (n = 140) or Step-Dep (n = 96) which consisted of four sequential treatment steps: watchful waiting, guided self-help, problem solving treatment and referral to a general practitioner. Primary outcomes were quality-adjusted life years (QALYs) and cumulative incidence of major depression. Costs were measured every 3 months. Missing data was imputed using multiple imputation. Uncertainty around cost-effectiveness outcomes was estimated using bootstrapping and presented in cost-effectiveness planes and acceptability curves. Results There were no significant differences in QALYs or depression incidence between treatment groups. Secondary care costs (mean difference €1644, 95% CI €344; €3370) and informal care costs (mean difference €1930, 95% CI €528; €4089) were significantly higher in the Step-Dep group than in the usual care group. The difference in total societal costs (€1001, 95% CI €-3975; €6409) was not statistically significant. The probability of the Step-Dep intervention being cost-effective was low, with a maximum of 0.41 at a ceiling ratio of €30,000 per QALY gained and 0.32 at a ceiling ratio of €0 per prevented case of major depression. Conclusions The Step-Dep intervention is not cost-effective compared to usual care in a population of patients with DM2/CHD and subthreshold depression. Therefore, widespread implementation cannot be recommended

Longitudinal associations between depression and diabetes complications: a systematic review and meta-analysis

Aims. To conduct a systematic review and meta-analysis of longitudinal studies assessing the bi- directional association between depression and diabetes macrovascular and microvascular complications. Methods. Embase, Medline, and PsycINFO databases were searched from inception through 27th November 2017. A total of 4,592 abstracts were screened for eligibility. Meta-analyses used multilevel random/mixed-effects models. Quality was assessed using the Newcastle-Ottawa scale. Results. 22 studies were included in the systematic review. 16 studies examined the relationship between baseline depression and incident diabetes complications, of which nine studies involving over 1 million participants were suitable for meta-analysis. Depression was associated with an increased risk for incident macrovascular (Hazard Ratio HR=1.38; 95%CI: 1.30-1.47) and microvascular disease (HR=1.33; 95%CI: 1.25-1.41). Six studies examined the association between baseline diabetes complications and subsequent depression, of which two involving over 230 000 participants were suitable for meta-analysis. The results showed that diabetes complications increased the risk of incident depressive disorder (HR=1.14; 95%CI: 1.07-1.21). The quality analysis showed increased risk of bias notably in the representativeness of selected cohorts and ascertainment of exposure and outcome. Conclusions. Depression in people with diabetes is associated with an increased risk of incident macrovascular and microvascular complications. The relationship between depression and diabetes complications appears bi-directional. However, the risk of developing diabetes complications in depressed people is higher than the risk of developing depression in people with diabetes complications. The underlying mechanisms warrant further research

Depression, Anxiety and Glucose Metabolism in the General Dutch Population: The New Hoorn Study

BACKGROUND: There is a well recognized association between depression and diabetes. However, there is little empirical data about the prevalence of depressive symptoms and anxiety among different groups of glucose metabolism in population based samples. The aim of this study was to determine whether the prevalence of increased levels of depression and anxiety is different between patients with type 2 diabetes and subjects with impaired glucose metabolism (IGM) and normal glucose metabolism (NGM). METHODOLOGY/PRINCIPAL FINDINGS: Cross-sectional data from a population-based cohort study of 2667 residents, 1261 men and 1406 women aged 40-65 years from the Hoorn region, the Netherlands. Depressive symptoms and anxiety were measured using the Centre for Epidemiologic Studies Depression Scale (CES-D, score >or=16) and the Hospital Anxiety and Depression Scale--Anxiety Subscale (HADS-A, score >or=8), respectively. Glucose metabolism status was determined by oral glucose tolerance test. In the total study population the prevalence of depressive symptoms and anxiety for the NGM, IGM and type 2 diabetes were 12.5, 12.2 and 21.0% (P = 0.004) and 15.0, 15.3 and 19.9% (p = 0.216), respectively. In men, the prevalence of depressive symptoms was 7.7, 9.5 and 19.6% (p<0.001), and in women 16.4, 15.8 and 22.6 (p = 0.318), for participants with NGM, IGM and type 2 diabetes, respectively. Anxiety was not associated with glucose metabolism when stratified for sex. Intergroup differences (NGM vs. IGM and IGM vs. type 2 diabetes) revealed that higher prevalences of depressive symptoms are mainly manifested in participants with type 2 diabetes, and not in participants with IGM. CONCLUSIONS: Depressive symptoms, but not anxiety are associated with glucose metabolism. This association is mainly determined by a higher prevalence of depressive symptoms in participants with type 2 diabetes and not in participants with IGM