24 resultados para MCM-41 type materials


Relevância:

30.00% 30.00%

Publicador:

Resumo:

Aims - A common variant, rs9939609, in the FTO (fat mass and obesity) gene is associated with adiposity in Europeans, explaining its relationship with diabetes. However, data are inconsistent in South Asians. Our aim was to investigate the association of the FTO rs9939609 variant with obesity, obesity-related traits and Type 2 diabetes in South Asian individuals, and to use meta-analyses to attempt to clarify to what extent BMI influences the association of FTO variants with diabetes in South Asians. Methods - We analysed rs9939609 in two studies of Pakistani individuals: 1666 adults aged = 40 years from the Karachi population-based Control of Blood Pressure and Risk Attenuation (COBRA) study and 2745 individuals of Punjabi ancestry who were part of a Type 2 diabetes case–control study (UK Asian Diabetes Study/Diabetes Genetics in Pakistan; UKADS/DGP). The main outcomes were BMI, waist circumference and diabetes. Regression analyses were performed to determine associations between FTO alleles and outcomes. Summary estimates were combined in a meta-analysis of 8091 South Asian individuals (3919 patients with Type 2 diabetes and 4172 control subjects), including those from two previous studies. Results - In the 4411 Pakistani individuals from this study, the age-, sex- and diabetes-adjusted association of FTO variant rs9939609 with BMI was 0.45 (95% CI 0.24–0.67) kg/m2 per A-allele (P = 3.0 × 10-5) and with waist circumference was 0.88 (95% CI 0.36–1.41) cm per A-allele (P = 0.001). The A-allele (30% frequency) was also significantly associated with Type 2 diabetes [per A-allele odds ratio (95% CI) 1.18 (1.07–1.30); P = 0.0009]. A meta-analysis of four South Asian studies with 8091 subjects showed that the FTO A-allele predisposes to Type 2 diabetes [1.22 (95% CI 1.14–1.31); P = 1.07 × 10-8] even after adjusting for BMI [1.18 (95% CI 1.10–1.27); P = 1.02 × 10-5] or waist circumference [1.18 (95% CI 1.10–1.27); P = 3.97 × 10-5]. Conclusions - The strong association between FTO genotype and BMI and waist circumference in South Asians is similar to that observed in Europeans. In contrast, the strong association of FTO genotype with diabetes is only partly accounted for by BMI.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Aim: To determine the impact of periodontitis on oxidative/inflammatory status and diabetes control in Type 2 diabetes. Materials and Methods: A comparative study of 20 Type 2 diabetes patients with periodontitis [body mass index (BMI) 31+5], 20-age/gender-matched, non-periodontitis Type 2 diabetes controls (BMI 29+6) and 20 non-diabetes periodontitis controls (BMI 25+4) had periodontal examinations and fasting blood samples collected. Oxidative stress was determined by plasma small molecule antioxidant capacity (pSMAC) and protein carbonyl levels; inflammatory status by total/differential leucocytes, fibrinogen and high sensitivity C-reactive protein (hsCRP); diabetes status by fasting glucose, HbA1c, lipid profile, insulin resistance and secretion. Statistical analysis was performed using SPSS. Results: pSMAC was lower (p=0.03) and protein carbonyls higher (p=0.007) in Type 2 diabetes patients with periodontitis compared with those without periodontitis. Periodontitis was associated with significantly higher HbA1c (p=0.002) and fasting glucose levels (p=0.04) and with lower ß-cell function (HOMA-ß; p=0.01) in diabetes patients. Periodontitis had little effect on inflammatory markers or lipid profiles, but Type 2 diabetes patients with periodontitis had higher levels of hsCRP than those without diabetes (p=0.004) and the lowest levels of HDL-cholesterol of all groups. Conclusion: Periodontitis is associated with increased oxidative stress and compromised glycaemic control in Type 2 diabetes patients.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The prevalence rates of type2 diabetes mellitus (T2DM) continues to rise among British Pakistanis. The aim of this project was to explore T2DM perceptions and any preventative intentions among British Pakistani women and to discover whether they are doing anything to prevent the onset in themselves and their families. Initially a systematic review was conducted to investigate 20 existing prevention interventions and to assess their effectiveness (n=12,419). Mixed methods approach was adopted and three studies were conducted. The first study consisted of two focus groups with T2DM mothers (n=8) and three focus groups with non-T2DM mothers (n=17). The second study consisted of four focus groups young British Pakistani females (n=11). All focus groups were transcribed verbatim and analysed using thematic analysis. Following these a quantitative study was undertaken comprising of a questionnaire survey; 12 prevention-perception items (derived from the qualitative data) and the Illness-Perception Questionnaire Revised (IPQ-R) using participants from the same populations: T2DM mothers (n=41), non-T2DM mother (n=47) and young women (n=42). Results were analysed using multiple/hierarchical regression. The systematic review highlighted that the most effective prevention programmes focussed on behaviour and lifestyle with a combination of support and education to participants. The research studies demonstrated that T2DM was seen as an older person’s disease to be dealt with if/when it happens. T2DM mothers demonstrated knowledge and prevention understanding. There were non-significant relationships between prevention perceptions and T2DM illness perceptions across all three groups. The finding of this thesis emphasised that lifestyle interventions are crucial to aiding T2DM preventions as a good healthy diet and regular physical activity are the key components to T2DM prevention, and the importance of personal experience in perceived severity and lay-beliefs regarding T2DM and on family/cultural influences in British-Pakistanis. The findings of this project can be used to design culturally specific interventions towards preventing T2DM in the British Pakistani community.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Pack aluminide coating is a useful method for conferring oxidation resistance on nickel-base superalloys. Nominally, these coatings have a matrix composed of a Ni-Al based B2-type phase (commonly denoted as Β). However, following high-temperature exposure in oxidative envi-ronments, aluminum is depleted from the coating. Aluminum depletion in turn, leads to de-stabilization of the Β phase, resulting in the formation of a characteristic lathlike Β-derivative microstructure. This article presents a transmission electron microscopy study of the formation of the lathlike Β-derivative microstructure using bulk nickel aluminides as model alloys. In the bulk nickel aluminides, the lathlike microstructure has been found to correspond to two distinct components: L10-type martensite and a new Β derivative. The new Β derivative is characterized and the conditions associated with the presence of this feature are identified and compared with those leading to the formation of the L10 martensitic phase. © 1995 The Minerals, Metals & Material Society.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The microstructural stability of aluminide diffusion coatings, prepared by means of a two-stage pack-aluminization treatment on single-crystal nickel-base superalloy substrates, is considered in this article. Edge-on specimens of coated superalloy are studied using transmission electron microscopy (TEM). The effects of coating thickness and post-coating heat treatment (duration, temperature, and atmosphere) on coating microstructure are examined. The article discusses the partial transformation of the matrix of the coating, from a B2-type phase (nominally NiAl) to a L12 phase (nominally Ni3(Al, Ti)), during exposure at temperatures of 850 °C and 950 °C in air and in vacuum for up to 138 hours. Three possible processes that can account for decom- position of the coating matrix are investigated, namely, interdiffusion between the coating and the substrate, oxidation of the coating surface, and aging of the coating. Of these processes, aging of the coating is shown to be the predominant factor in the coating transformation under the conditions considered. © 1992 The Minerals, Metals and Materials Society, and ASM International.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Simultaneous strain and temperature measurement for advanced 3-D braided composite materials using fibre-optic sensor technology is demonstrated, for the first time. These advanced 3-D braided composites can virtually eliminate the most serious problem of delamination for conventional composites. A tandem in-fibre Bragg-grating (FBG)/extrinsic Fabry-Perot interferometric sensor (EFPI) system with improved accuracy has been used to facilitate simultaneous temperature and strain measurement in this work. The non-symmetric distortion of the optical spectrum of the FBG, due to the combination of the FBG and the EFPI, is observed for the first time. Experimental and theoretical studies indicate that this type of distortion can affect the measurement accuracy seriously and it is mainly caused by the modulation of the periodic output of the EFPI. A simple method has been demonstrated to improve the accuracy for detection of the wavelength-shift of the FBG induced by temperature change. A strain accuracy of ∼ ±20 με and a temperature accuracy of ∼ ±1 °C have been achieved, which can meet the requirements for practical applications of 3-D braided composites. © 2002 Elsevier Science Ltd. All rights reserved.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

troduct I on . An observational longitudinal study. P ur P ose . Assess the relationship between obstructive sleep apnoea (OSA) and DR cross-sectionally and longitudinally. M ethods . Adults with Type 2 diabetes mellitus (T2DM), who were re - cruited from a hospital-based diabetes clinic in the UK. Patients with pre-existing OSA, end-stage renal disease and non-diabetic retinopa - thy were excluded. OSA (apnoea hypopnea index ≥ 5 events/hour) was assessed by a single overnight home-based cardio-respiratory study (Alice PDX, Philips Respironics, USA). DR was assessed us - ing retinal images between 2007 and 2012. Sight threatening diabetic retinopathy (STDR) was defined as presence of pre-proliferative or proliferative DR, maculopathy or photocoagulation. Advanced DR was defined as pre-proliferative or proliferative DR. r esults . 199 patients were included (57.3% (n=114) men, 47.7% (n=95) White Europeans). STDR and OSA prevalence were 38.7% (n=77) and 62.8% respectively. A t b A sel I ne . STR prevalence was higher in patients with OSA (OSA+) compared to those without OSA (OSA-) [48.8% n=61 vs. 21.6% n=16, p<0.001]. After adjustment for confounders, OSA remained independently associated with STR (OR 3.7, 95% CI 1.6-8.9, p=0.006), maculopathy (OR 4.5, 95% CI 1.8-11.4, p=0.002) and advanced DR (OR 3.9, 95% CI 1.02-15.3, p=0.047). Mild and moderate to severe OSA were independently associated with STR and maculopathy and only moderate to severe OSA was associated with advanced DR following adjustment for con - founders. l ong I tud I n A lly . Over the follow-up period of (4.4±1 years), more OSA+ patients progressed from no or background DR to advanced DR (15.3% (n=17) vs. 3% (n=2), p=0.01). OSA was an independent pre - dictor of advanced DR development after adjustment for confounders (OR 6.6, 95% CI 1.2-35.1, p=0.03). OSA did not predict the develop - ment of maculopathy. c onclus I ons . OSA is independently associated with STR and predicts the development of preproliferative and proliferative DR. Intervention - al studies are needed to assess the impact of OSA treatment on DR.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

CuAlO2 has been examined as a potential luminescent material by substituting Eu for Al cations in the delafossite structure. CuAlO2:Eu3+ nanofibers have been prepared via electrospinning for the ease of mitigating synthesis requirements and for future optoelectronics and emerging applications. Single-phase CuAlO2 fibers could be obtained at a temperature of 1100 °C in air. The Eu was successfully doped in the delafossite structure and two strong emission bands at ~405 and 610 nm were observed in the photoluminescence spectra. These bands are due to the intrinsic near-band-edge transition of CuAlO2 and the f-f transition of the Eu3+ activator, respectively. Further electrical characterization indicated that these fibers exhibit semiconducting behavior and the introduction of Eu could act as band-edge modifiers, thus changing the thermal activation energies. In light of this study, CuAlO2:Eu3+ fibers with both strong photoluminescence and p-type conductivity could be produced by tailoring the rare earth doping concentrations.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Background and aims: The selective SGLT2 inhibitor dapagliflozin (DAPA) reduces hyperglycaemia independently of insulin secretion or action by inhibiting renal glucose reabsorption. This study (MB102014) is a randomised double-blind, placebo (PBO)-controlled trial of DAPA added to metformin (MET) in T2DM (n=546) inadequately controlled with MET alone. Previously reported short-term data at week 24 showed significant mean reductions in the primary [HbA1c] and secondary [fasting plasma glucose (FPG) and weight] endpoints with DAPA compared to PBO. Here we report efficacy and safety results at week 102 of the long-term extension. Materials and methods: Patients aged 18-77 years with HbA1c 7-10% received DAPA 2.5 mg, 5 mg, 10 mg or PBO, plus open-label MET (≥1500mg/d). Exploratory endpoints at week 102 included changes from baseline in HbA1c, FPG and weight, and were analyzed by longitudinal repeated measures analysis. Results: Overall 71.2% of patients completed 102 weeks of the study; fewer on PBO (63.5%) than on DAPA 2.5 mg, 5 mg, and 10 mg (68.3%, 73.0%, 79.8%), due mainly to more patients on PBO discontinuing for lack of efficacy. At week 102, all DAPA groups showed greater mean reductions from baseline in HbA1c, FPG and weight compared to PBO (table), effects that were similar to those observed at week 24 and maintained throughout the trial. More patients at week 102 also achieved a therapeutic response of HbA1c<7% with DAPA 2.5 mg, 5 mg, and 10 mg (20.7%, 26.4%, 31.5%) than with PBO (15.4%). Adverse events (AEs), serious AEs and AEs leading to discontinuation were balanced across all groups. Signs and symptoms suggestive of genital infection (GenInf) were reported in 11.7%, 14.6%, 12.6% (DAPA 2.5 mg, 5 mg, 10 mg) and 5.1% (PBO) of patients, with 1 discontinuation due to GenInf. Signs and symptoms suggestive of urinary tract infection (UTI) were reported in 8.0%, 8.8%, 13.3% (DAPA 2.5 mg, 5 mg, 10 mg) and 8.0% (PBO), with 1 discontinuation due to UTI. No event of pyelonephritis was reported. Conclusion: In comparison to PBO, DAPA added to MET over 102 weeks demonstrated greater and sustained improvements in glycaemic control, clinically meaningful reduction in weight, and no increased risk of hypoglycaemia in patients with T2DM inadequately controlled with MET alone.