Electrochemical analysis of asymmetric supercapacitors based on BiCoO3@g-C3N4 nanocomposites.

Supercapacitors are gaining popularity these days because of their good cycle stability, superior specific capacitance, high power density, and energy density. Herein, we report the synthesis of bismuth cobalt oxide (BiCoO3) combined with graphitic carbon nitride (g-C3N4) by the hydrothermal method. The BiCoO3@g-C3N4 nanocomposite was well characterized using XRD, FE-SEM, FT-IR, and DRS-UV techniques. The supercapacitor properties of the BiCoO3@g-C3N4 nanocomposite were then studied using cyclic voltammetry, galvanic charging-discharging, and impedance spectroscopy techniques. Due to the synergistic effect, BiCoO3@g-C3N4 showed a high specific capacitance value of 341 F g-1 at a current density of 1 A g-1 and excellent retention of specific capacitance (98.82%) after 1000 cycles and a high power density of 1125 W kg-1. Using the impedance spectroscopy technique, the charge transfer resistance of BiCoO3, g-C3N4, and BiCoO3@g-C3N4 was measured. BiCoO3@g-C3N4 showed a low charge transfer resistance compared with BiCoO3 and g-C3N4. The asymmetric supercapacitor (ASC) device was prepared using activated carbon (negative side) and BiCoO3@g-C3N4 (positive side) electrodes. It showed a specific capacitance of 129 F g-1 at 1 A g-1, power density 2800 W kg-1 and energy density 35 W h kg-1. Finally, we conclude that, due to the high specific capacitance, good cycle retention, fast redox activity, and low charge transfer resistance BiCoO3@g-C3N4 is a good electrode material for energy storage applications.

Early screening for gestational diabetes mellitus is not associated with improved pregnancy outcomes: an observational study including 9795 women.

AIMS: In addition to screening for hyperglycaemia during pregnancy after 24 weeks of gestation (WG), the current guidelines also suggest screening in early pregnancy and referring women with early gestational diabetes mellitus (eGDM) or overt diabetes (OD) for immediate care. Our aim was to evaluate this strategy. METHODS: This study evaluated, at our hospital (2012-2016), whether the incidence of a predefined composite outcome (preeclampsia, large-for-gestational-age infant, shoulder dystocia) and secondary outcomes was different when women were screened only after 22WG ('late screening only') or before 22WG and treated for eGDM or OD if present, with repeat screening after 22WG if absent ('early ± late screening'). RESULTS: Early ± late screening (n = 4605, 47.0%) increased between 2012 and 2016 (P < 0.0001) and was associated with more risk factors for GDM than late screening only. Glycaemic status differed in both groups (early ± late screening: eGDM 10.3%, GDM 12.1%, OD 0.9% vs. late screening only: GDM 16.8%, OD 1.2%; P < 0.001), with a higher rate of insulin therapy (8.9% vs. 6.0%; P < 0.001) and less gestational weight gain (11.1 ± 5.4 kg vs. 11.4 ± 5.5 kg; P = 0.013) in the early ± late screening group. Rates of those meeting the composite criterion were similar in both groups [11.6% vs. 12.0%, respectively; odds ratio (OR): 1.040, 95% confidence interval (CI): 0.920-1.176; P = 0.53] and remained comparable after adjusting for Propensity Scores (OR: 1.046, 95% CI: 0.924-1.185; P = 0.4790). Rates for secondary outcomes were also similar in both groups. CONCLUSION: While a strategy including early measurement of fasting plasma glucose during pregnancy increases the incidence and care of hyperglycaemia during pregnancy, it may not significantly improve pregnancy outcomes.

Are Obese Individuals with no Feature of Metabolic Syndrome but Increased Waist Circumference Really Healthy? A Cross Sectional Study.

AIM: Patients displaying the metabolically healthy but obese phenotype have an intermediate cardiometabolic prognosis compared to normal weight healthy and metabolically unhealthy obese subjects. We aimed to evaluate the proportion of patients with a definite metabolically healthy obese phenotype and better characterize them. METHODS: Definite metabolically healthy obese phenotype was defined as having none of the International Diabetes Federation metabolic syndrome criteria, excluding waist circumference. We recruited 1 159 obese patients (body mass index 38.4±6.3 kg/m(2)) including 943 women, without known diabetes. Patients were characterized for cardiometabolic disorders. RESULTS: As the 202 (17.4%) metabolically healthy obese individuals were younger and had lower body mass indexes than the 957 metabolically unhealthy obese patients, they were matched for gender, age and body mass index with 404 metabolically unhealthy obese patients. In addition to the features of metabolic syndrome, when compared to unhealthy subjects, definite metabolically healthy obese patients were less frequently found with either homeostasis model assessment of insulin resistance index>3 (23.6 vs. 38.9%, p<0.001), or abnormal oral glucose tolerance test (13.9 vs. 33.9%, p<0.001), or HbA1c value≥5.7% (43.9 vs. 54.2%, p<0.05) or pulse pressure≥60 mmHg (11.7 vs. 64.9%, p<0.001). However, there were no significant differences in the prevalence of microalbuminuria (11.1 vs. 12.3%), cardiac autonomic dysfunction (45.5 vs. 35.3%) and fatty liver index ≥ 60 (5.6 vs. 10.2%). CONCLUSION: Our data do not support the characterization of metabolically healthy obesity, even definite, as really healthy, as many patients with this phenotype have abnormal cardiovascular markers and glucose or liver abnormalities. HbA1c measurement seems to be more sensitive than OGTT to detect dysglycemia in this population.

Fetal gender is not associated with either gestational diabetes mellitus or placental weight: A cohort study.

AIM: This study assessed whether male fetal gender increases the risk of maternal gestational diabetes mellitus (GDM) and investigated the association with placental weight. METHODS: The study included 20,149 women without pregestational diabetes who delivered singletons at our hospital between January 2002 and December 2010. There was universal screening for GDM, and all placentas were weighed at delivery. RESULTS: GDM (affecting 14.2% of women) was not associated with fetal gender (male fetuses in women without and with GDM: 51.8% vs. 51.7%, respectively; P=0.957), and remained likewise after logistic-regression analysis of risk factors for GDM (OR: 1.007, 95% CI: 0.930-1.091; P=0.858). Placental weights were 600±126g, 596±123g, 584±118g and 587±181g in women with GDM/female, GDM/male, no GDM/female and no GDM/male fetuses, respectively (GDM effect: P=0.017; gender effect: P=0.41; GDM * gender effect: P=0.16). CONCLUSION: The present results suggest that fetal gender is not associated with GDM and, while placental weights were higher in cases of GDM, there were still no gender effects.

[Relationship between blood pressure, heart rate and cardiac autonomic dysfunction in non-diabetic obese patients]. / Relation entre pression artérielle, fréquence cardiaque et dysfonction autonome cardiaque chez les obèses non diabétiques.

RATIONALE: Some studies suggest that a high heart rate (HR) would be predictive of the incidence of an elevated blood pressure (BP). Cardiac autonomic dysfunction (CAD) affects a high proportion of obese patients. CAD could be involved in BP increase. Our aim was to examine the relationship between CAD, HR and BP in obese patients without known diabetes. PATIENTS AND METHODS: We included 428 overweight or obese patients. CAD was assessed by analyzing HR variations during three standard tests (Valsalva, deep breathing, lying-to-standing), which are mostly dependent on vagal control. An oral load in glucose was performed and the Matsuda index was calculated. RESULTS: The population was separated in 4 groups according to the grade of CAD (no or only one abnormal test, 2 or 3 abnormal tests) and HR (< or ≥ 75 bpm). Age was similar in the four groups. Systolic (P=0.05), diastolic (P<0.005) and mean BP (P<0.001) differed significantly between the 4 groups, and was the highest in the group of patients who had 2 or 3 abnormal tests and HR ≥ 75 bpm. Matsuda index differed across the groups (P=0.018) and was the lowest in this group. CONCLUSION: These data indicate that among overweight or obese patients with a defect in cardiac vagal activity BP is elevated only in those with a high heart rate, which is indicative of a more marked insulin resistance and probably an excess in sympathetic activity.

Optical studies of pulsed laser deposited nanostructured Pb(Zr0.52Ti0.48)O3 thin film by spectroscopic ellipsometry.

Pulsed laser deposition method was employed to grow nanostructured Pb(Zr0.52Ti0.48)O3 (PZT) thin film on Si(100) substrate. The structural and morphological properties of the thin film were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM) respectively. Optical properties of PZT thin film were studied using spectroscopic ellipsometry (SE) and a four layer model was applied. Spectra of ellipsometric parameters such as psi and delta were measured as a function of energy at room temperature. The refractive index (n), extinction coefficient (k), absorption coefficient (alpha) and the dielectric constants (epsilon(r) and epsilon(i)) of the thin film were obtained as a function of wavelength (200 to 900 nm range). The energy gap (E(g)) of the PZT thin film was estimated to be 3.65 eV. The thickness of the thin films was determined by the ellipsometric data (524 nm) and grain size is found to be in the range of 50-100 nm.

Pulsed laser deposition and ferroelectric characterization of nanostructured perovskite lead zirconate titanate (52/48) thin films.

Perovskite lead zirconate titanate nanostructured (PZT) thin films with Zr/Ti ratio of 52/48 were deposited on Pt/TiO2/SiO2/Si(100) substrate using pulsed laser deposition method. A metal/ ferroelectric/metal (MFM) structure was used for ferroelectric property measurements, formed by depositing gold electrode on top of the film. A Nd:YAG UV laser having a wavelength of 355 nm and an energy fluence of -2.7 J/cm2 was used to deposit the film. The film was deposited on platinum (Pt) coated silicon substrate at the substrate temperature of 600 degrees C and the base vacuum of 10(-6) mbar. The scanning electron microscopy (SEM) images revealed well-crystallized films with a fine microstructure and an average grain size of - 50 nm. The ferroelectric properties of the film were studied and the results were discussed. The voltage dependent Polarization versus Electric field hysteresis measurements of PZT (52/48) pellet showed a well-defined hysteresis loop with a fairly high remnant polarization (P(r)) and low coercive field (E(c)).

Haemoglobin glycation may partly explain the discordance between HbA1c measurement and oral glucose tolerance test to diagnose dysglycaemia in overweight/obese subjects.

AIM: This study assessed whether the poor correlation between HbA1c and oral glucose tolerance test (OGTT) for dysglycaemia diagnosis may be explained by haemoglobin glycation (HbG). METHODS: A total of 1033 consecutive overweight or obese patients with no known diabetes underwent OGTT and measurement of HbA1c to diagnose diabetes and dysglycaemia (American Diabetes Association criteria). For each OGTT result category, low, medium and high HbG was defined according to the mean HbA1c/fructosamine ratio and mean fructosamine. High HbG was defined as values greater than mean values in each OGTT category for both HbA1c/fructosamine ratio and fructosamine levels, and low HbG was defined as lower values of both. The remaining patients were considered medium HbG. RESULTS: Based on OGTT and HbA1c values, 267 (25.8%) and 443 (42.8%) patients had intermediate hyperglycaemia, and 66 (6.4%) and 95 (9.2%) patients had diabetes, respectively. The results were discordant for intermediate hyperglycaemia or diabetes diagnosis in 41.7% and for diabetes diagnosis in 10.0% of the patients. The proportion of patients with HbA1c≥6.5%, but without OGTT-diagnosed diabetes, was 0%, 3.8% and 32.8% in the low-HbG, medium-HbG and high-HbG groups, respectively. In contrast, the proportion of patients with HbA1c<5.7%, but with an abnormal OGTT, was 30.4%, 11.1% and 0%, respectively. The AUROC of HbA1c to detect OGTT-diagnosed diabetes was better in the medium-HbG group [0.874 (0.816-0.931)] than in those with low or high HbG [0.628 (0.489-0.768); P<0.01]. Only age was independently associated with high-HbG status [10-year OR: 1.3 (1.1-1.5); P<0.0001]. CONCLUSION: Haemoglobin glycation may explain many of the discordant results between HbA1c and OGTT when used for dysglycaemia diagnosis.

Use of clinical scores to detect dysglycaemia in overweight or obese women.

AIMS: To test if the use of either HbA(1c) level or calculated clinical scores including two published scores and a new score (the Bondy score) could help in selecting overweight or obese women who should benefit from oral glucose tolerance test (OGTT) to detect dysglycaemia. METHODS: The French Data from an Epidemiological Study on the Insulin Resistance Syndrome (DESIR) score and the Finnish Diabetes risk score (Findrisk) were calculated, whereas the Bondy score was built in a development sample of 698 women, BMI 37±7 kg/m(2), without known diabetes. External validation was performed in a validation sample of 212 women. RESULTS: A dysglycaemia (according to OGTT results, WHO criteria) was diagnosed in 161 (23.1%) patients. Sensitivity of fasting plasma glucose (FPG)≥6.1 mmol/l and HbA(1c)≥6% to identify dysglycaemia were respectively 27 and 41%. Areas under Receiver Operator Curve (AROC) of HbA(1c), DESIR score and Findrisk to detect dysglycaemia were 0.630 [95% confidence interval 0.580-0.680], 0.606 [0.561-0.652] and 0.635 [0.588-0.683], respectively. The Bondy score, based on age and waist circumference, had a better AROC (0.674 [0.626-0.721]) than the DESIR score (P<0.05). These performances were confirmed in the validation sample. Performing OGTT only in subjects with a Bondy score≥4 (41% of the sample) had a sensitivity of 61% and a better net benefit (0.128) than measuring FPG in all subjects (0.069). CONCLUSION: Performing OGTT in obese women selected on a simple clinical score is more sensitive to identify dysglycaemia than measuring FPG in all of them and may be cost-effective.

What would be the outcome if the American Diabetes Association recommendations of 2010 had been followed in our practice in 1998-2006?

AIMS: In 2010, the American Diabetes Association has published recommendations on the population to be screened for dysglycaemia; the diagnostic criteria for intermediate hyperglycaemia and diabetes using oral glucose tolerance testing and HbA(1c); and the patients eligible for treatment with metformin. We aimed to evaluate the consequences of screening with oral glucose tolerance test or HbA(1c) in an at-risk population. METHODS: Among 1177 overweight or obese consecutive adults without known diabetes who were referred to our department for weight management, we selected 1157 individuals (83% female; 80% European) fulfilling the American Diabetes Association 2010 criteria for dysglycaemia screening. RESULTS: Mean age was 41.2 ± 13 years, BMI 37.0 ± 7.2 kg/m(2), fasting plasma glucose 4.9 ± 0.8 mmol/l and HbA(1c) (turbidimetric immunoassay) 5.7 ± 0.7% (39 mmol/mol). Based on oral glucose tolerance test and HbA(1c), respectively, 76 (6.6%) and 113 (9.8%) patients had diabetes, including 34 sharing both criteria; 307 (26.5%) and 478 (41.3%) had intermediate hyperglycaemia; and 130 (11.2%) and 255 (22.0%) would be treated with metformin. The sensitivity/specificity of HbA(1c) ≥ 6.5% (48 mmol/mol) for the diagnosis of diabetes according to the oral glucose tolerance test were 44.7/92.7%. Diabetes risk scores and UK Prospective Diabetes Study cardiovascular risk score were the highest in the 130 patients having both an abnormal oral glucose tolerance test and HbA(1c) ≥ 5.7%. CONCLUSIONS: In a population at risk for diabetes, the HbA(1c) strategy could lead to diagnosing more cases of dysglycaemia and to treating more patients with metformin than the oral glucose tolerance test strategy. The consistency of either diagnostic criteria was low. The patients with the highest a priori risk of diabetes and cardiovascular disease were those fulfilling both oral glucose tolerance test and HbA(1c) criteria.

A large proportion of prediabetes and diabetes goes undiagnosed when only fasting plasma glucose and/or HbA1c are measured in overweight or obese patients.

AIMS: The purposes of the study were to determine the prevalence of unrecognized dysglycaemia in overweight (body mass index [BMI] 25-29.9 kg/m(2)) and obese (BMI ≥30 kg/m(2)) patients, to assess the extent to which measures of fasting plasma glucose (FPG) and/or HbA(1c), compared with oral glucose tolerance tests (OGTTs), misdiagnose dysglycaemia, and to determine the factors associated with an isolated abnormal post-OGTT glucose value. METHODS: OGTT was performed and HbA(1c) was measured in 1283 inpatients with BMI scores ≥ 25 kg/m(2) and no history of dysglycaemia. RESULTS: Prediabetes was found in 257 (20.0%) subjects (197 with impaired glucose tolerance, 29 with impaired fasting glucose, 31 with both) and diabetes in 77 (6.0%), including 22 with FPG ≥ 7 mmol/L (WHO definition). The sensitivity of FPG >6 mmol/L, FPG >5.5 mmol/L, HbA(1c) ≥ 6% and the recommendations of the French National Agency of Accreditation and Evaluation in Health Care (ANAES) to identify patients with abnormal OGTTs was 29.9, 41.3, 36.8 and 15.6%, respectively. The factors that were independently associated with diabetes in obese women with FPG <7 mmol/L were age (per 10 years: OR 1.54 [1.00-2.11]; P=0.049) and FPG (OR 6.1 [1.4-30.0]; P=0.014), whereas age (OR 1.26 [1.09-1.44]; P<0.01) and waist circumference (per 10 cm: OR 1.17 [1.01-1.33]; P<0.05) were independently associated with dysglycaemia in obese women with FPG <6.1 mmol/L. CONCLUSION: In overweight and obese patients: dysglycaemia is commonly seen; FPG alone, compared with OGTT, failed to diagnose 70% of dysglycaemia cases; FPG >5.5 mmol/L and HbA(1c) ≥ 6.0% are not necessarily substitutes for OGTT; and older age and larger waist circumference should be used to select those obese women with normal FPG who might further benefit from OGTTs to diagnose dysglycaemia.