Improving thermal conductivity of Al/SiC composites by post-oxidization of reaction-bonded silicon carbide preforms.

High thermal conductivity aluminium-based silicon carbide (Al/SiC) composites were successfully fabricated through post-oxidization of reaction-bonded silicon carbide preforms (RS preforms), utilizing vacuum pressure infiltration technology. The study investigated the regulation of interfacial reactions in conventional sintering and reaction sintering. Conventional sintering introduced a large amount of SiO2, which negatively impacted the thermal conductivity of the Al/SiC composite, but the reaction sintering not. The proposed post-oxidization treatment of RS preforms effectively removed residual carbon from the SiC particle surfaces, thereby forestalling the formation of Al4C3. Furthermore, the post-oxidization treatment effectively formed lightweight SiO2 deposits onto the surface of SiC particles, improving Al-SiC interfacial wettability and reducing thermal resistance, thereby enhancing composite thermal conductivity. Notably, the thermal conductivity of the post-oxidized sample exhibited an increase of 6.5% compared to the untreated sample. The study also evaluated the impact of particle size distribution on volume fraction and thermal properties. The optimized Al/SiC composites yielded thermal conductivity, coefficient of thermal expansion, bending strength, and Young's modulus values of 237.3 W/m K, 8.5 × 10-6/°C, 325 MPa, and 75.9 GPa, respectively.

Patterned immobilization of polyoxometalate-loaded mesoporous silica particles via amine-ene Michael additions on alkene functionalized surfaces.

Polyoxometalates (POM) are anionic oxoclusters of early transition metals that are of great interest for a variety of applications, including the development of sensors and catalysts. A crucial step in the use of POM in functional materials is the production of composites that can be further processed into complex materials, e.g. by printing on different substrates. In this work, we present an immobilization approach for POMs that involves two key processes: first, the stable encapsulation of POMs in the pores of mesoporous silica nanoparticles (MSPs) and, second, the formation of microstructured arrays with these POM-loaded nanoparticles. Specifically, we have developed a strategy that leads to water-stable, POM-loaded mesoporous silica that can be covalently linked to alkene-bearing surfaces by amine-Michael addition and patterned into microarrays by scanning probe lithography (SPL). The immobilization strategy presented facilitates the printing of hybrid POM-loaded nanomaterials onto different surfaces and provides a versatile method for the fabrication of POM-based composites. Importantly, POM-loaded MSPs are useful in applications such as microfluidic systems and sensors that require frequent washing. Overall, this method is a promising way to produce surface-printed POM arrays that can be used for a wide range of applications.

Risk factors for peripheral artery disease and diabetic peripheral neuropathy among patients with type 2 diabetes.

AIMS: To investigate the prevalence of peripheral artery disease (PAD) and diabetic peripheral neuropathy (DPN) and the associated risk factors among Chinese patients with type 2 diabetes mellitus. METHODS: A cross-sectional study was conducted using data between November 1, 2018, and December 31, 2022. PAD was defined as ABI ≤ 0.9. DPN diagnosis involved specialized physician assessments using questionnaires and vibration perception threshold tests. Logistic regression analysis was used to identify related factors. We also evaluated the association between the clustering of risk factors and disease incidence. RESULTS: The study population comprised 13,315 patients (mean age: 63.3 years). 4.9 % of the patients had PAD and 43.9 % had DPN. Multivariate regression analysis revealed advanced age, smoking, hypertension, coronary heart disease, dyslipidemia, elevated HbA1c, and uric acid levels as independent risk factors for PAD. For DPN, independent risk factors included advanced age, female gender, hypertension, coronary heart disease, elevated total cholesterol, triglycerides, lipoprotein(a), fasting plasma glucose, HbA1c, alkaline phosphatase, cystatin C, albumin-to-creatinine ratio, and elevated homocysteine levels, whereas apolipoprotein A was a protective factor. The clustering of risk factors was prevalent and associated with higher disease risk. CONCLUSIONS: Our study contributed to identifying high-risk individuals and improving lower limb health among diabetic individuals.

Fabrication of polydimethylsiloxane (PDMS)-Based Flexible Surface-Enhanced Raman Scattering (SERS) Substrate for Ultrasensitive Detection.

This article presents a fabrication method for a flexible substrate designed for Surface-Enhanced Raman Scattering (SERS). Silver nanoparticles (AgNPs) were synthesized through a complexation reaction involving silver nitrate (AgNO3) and ammonia, followed by reduction using glucose. The resulting AgNPs exhibited a uniform size distribution ranging from 20 nm to 50 nm. Subsequently, 3-aminopropyl triethoxysilane (APTES) was employed to modify a PDMS substrate that had been surface-treated with oxygen plasma. This process facilitated the self-assembly of AgNPs onto the substrate. A systematic evaluation of the impact of various experimental conditions on substrate performance led to the development of a SERS substrate with excellent performance and an Enhanced Factor (EF). Utilizing this substrate, impressive detection limits of 10-10 M for R6G (Rhodamine 6G) and 10-8 M for Thiram were achieved. The substrate was successfully employed for detecting pesticide residues on apples, yielding highly satisfactory results. The flexible SERS substrate demonstrates great potential for real-world applications, including detection in complex scenarios.

Mortality following fragility hip fracture in China: a record linkage study.

Mortality risk declined over time. Patients with fragility hip fracture experienced an approximate ninefold excess mortality, peaking shortly after fracture, in comparison with that of the general population. Continuous efforts in lowering the occurrence of hip fracture have the potential to improve the survival of the elderly population in China. PURPOSE: Hip fractures in older adults often lead to an elevated risk of death. However, few studies investigated mortality risk following hip fracture in mainland China. This retrospective cohort study aimed to evaluate the crude mortality and excess mortality after fragility hip fractures in Lishui residents aged 50 years and older. METHODS: Patients having a fragility hip fracture between October 2013 and August 2019 were identified from the Lishui District Inpatient Data Collection and followed up until August 2020. Death information was ascertained from the linked death registry records. We calculated the follow-up mortality rate and corresponding 95% confidence intervals (CIs) as well as the standard mortality ratios (SMRs) in comparison with the mortality rates of Lishui residents. RESULTS: During the study period, a total of 808 patients (63.4% females) with an average age of 75 years were admitted for fragility hip fractures. The 1st, 2nd, and 3rd year follow-up mortality rates were 16.51, 6.06, and 5.03 per 100 person-year, respectively. The SMRs were 8.46 (6.94, 9.97), 5.74 (4.86, 6.63), and 4.63 (3.98, 5.27) for the 1st, 2nd, and 3rd year following fragility hip fracture. CONCLUSION: Although mortality risk declined over time, patients with fragility hip fracture experienced an approximate ninefold excess mortality, peaking shortly after fracture, in comparison with that of the general population. Continuous efforts in lowering the occurrence of hip fracture have the potential to improve the survival of the elderly population in China.

α-Ketoglutarate stimulates cell growth through the improvement of glucose and glutamine metabolism in C2C12 cell culture.

Introduction: Cellular adaptation to physical training and energy metabolism play an important role during physical exercise. This study sought to investigate the effects of α-KG on cell growth and energy metabolism in C2C12 cell culture. Methods: C2C12 cells were cultured in media pretreated without (control) or with α-KG at different concentrations, and cells and media were harvested every 24 h for 8 days. From cell counts, specific cell growth rate (SGR) and doubling time were calculated. The content of glucose, glutamine, lactate, and ammonia in media was determined, and the specific consumption rate (SCR) or production rate (SPR) was calculated. Additionally, cell colony-forming efficiency (CFE) was determined. Results: The control cells showed a CFE at 50%, a typical cell growth curve in the first 5 days with a mean SGR at 0.86/day, and a mean cell count doubling time at 19.4 h. In the group with α-KG at 100 mM, the cells underwent rapid cell death, and thus no further analysis was made. The treatment with α-KG at lower concentrations (0.1 mM and 1.0 mM) led to a higher CFE at 68 and 55%, respectively, whereas those in groups with higher α-KG concentration decreased (10 and 6% for 20 mM and 30 mM α-KG, respectively). The mean SGR was 0.95/day, 0.94/day, 0.77/day, 0.71/day, and 0.65/day for groups treated with α-KG at 0.1, 1.0, 10.0, 20.0, and 30.0 mM, respectively, and the corresponding cell count doubling time was 17.6, 17.8, 20.9, 24.6, and 24.7 h, respectively. In comparison with that of the control group, the mean glucose SCR decreased in all the groups treated with α-KG, while the mean glutamine SCR remained unchanged; the mean lactate SPR increased in the groups treated with α-KG ≥ 20.0 mM. Finally, the mean SPR of ammonia was lower in all α-KG groups than that in the control. Discussion and conclusion: The treatment with α-KG at lower concentrations increased cell growth whereas at higher concentrations decreased cell growth, and α-KG reduced glucose consumption and ammonia production. Therefore, α-KG stimulates cell growth in a dose-dependent manner, which is likely through the improvement of glucose and glutamine metabolism in a C2C12 culture setting.

Optical metasurfaces for multiplex high-performance grating-type structural colors.

Optical metasurfaces provide a significant approach for the production of structural colors due to their excellent optical control abilities. Herein, we propose trapezoidal structural metasurfaces for achieving multiplex grating-type structural colors with high comprehensive performance originating from the anomalous reflection dispersion in the visible band. Single trapezoidal metasurfaces with different x-direction periods can tune the angular dispersion regularly from 0.036 rad/nm to 0.224 rad/nm to generate various structural colors, and composite trapezoidal metasurfaces with three kinds of combinations can achieve multiplex sets of structural colors. The brightness can be controlled by adjusting the distance between the trapezoids in a pair accurately. The designed structural colors have higher saturation than traditional pigmentary colors, whose excitation purity can reach 1.00. The gamut is about 158.1% of the Adobe RGB standard. This research has application potential in ultrafine displays, information encryption, optical storage, and anti-counterfeit tagging.

Multiplexed Covalent Patterns on Double-Reactive Porous Coating.

We have conceptualized and demonstrated an approach based on the combination of hydrophobicity, a substrate-independent dip coating as porous material with double residual chemical reactivities for implementing multiplexed, miniaturized and unclonable bulk-infused patterns of different fluorophores following distinct reaction pathways. The embedded hydrophobicity (∼102°) restricted the unwanted spreading of beaded aqueous ink on the coating. The constructions of micropatterns on porous dip-coating via ink-jet printing or microchannel cantilever spotting offered orthogonal read-out and remained readable even after removal of the exterior of the coating.

Effectiveness of telemedicine for pregnant women with gestational diabetes mellitus: an updated meta-analysis of 32 randomized controlled trials with trial sequential analysis.

BACKGROUND: Gestational diabetes mellitus (GDM) is now a global health problem. Poor blood glucose control during pregnancy may lead to maternal and neonatal/foetal complications. Recently, the development of information and communication technology has resulted in new technical support for the clinical care of GDM. Telemedicine is defined as health services and medical activities provided by healthcare professionals through remote communication technologies. This study aimed to update the systematic review of the effectiveness of telemedicine interventions on glycaemic control and pregnancy outcomes in pregnant women with GDM. METHODS: We searched the Web of Science, PubMed, Scopus, Cochrane Central Register of Controlled Trials, Chinese National Knowledge Infrastructure, Wan-fang Database, China Biology Medicine and VIP Database for randomized controlled trials (RCTs) related to the effectiveness of telemedicine interventions for GDM from database inception to July 31st, 2019. Languages were limited to English and Chinese. Literature screening, data extraction and assessment of the risk of bias were completed independently by two reviewers. Meta-analysis and trial sequential analysis were conducted in Stata 14.0 and TSA v0.9.5.10 beta, respectively. RESULTS: A total of 32 RCTs were identified, with a total of 5108 patients. The meta-analysis showed that telemedicine group had significant improvements in controlling glycated haemoglobin (HbA1c) [mean difference (MD) = - 0.70, P < 0.01], fasting blood glucose (FBG) (MD = -0.52, P < 0.01) and 2-h postprandial blood glucose (2hBG) (MD = -1.03, P = 0.01) compared to the corresponding parameters in the standard care group. In the telemedicine group, lower incidences of caesarean section [relative risk (RR) = 0.82, P = 0.02], neonatal hypoglycaemia (RR = 0.67, P < 0.01), premature rupture of membranes (RR = 0.61, P < 0.01), macrosomia (RR = 0.49, P < 0.01), pregnancy-induced hypertension or preeclampsia (RR = 0.48, P < 0.01), preterm birth (RR = 0.27, P < 0.01), neonatal asphyxia (RR = 0.17, P < 0.01), and polyhydramnios (RR = 0.16, P < 0.01) were found. The trial sequential analyses conclusively demonstrated that the meta-analytic results of the change in HbA1c, the change in 2hBG, the change in FBG, the incidence rates of caesarean section, pregnancy-induced hypertension or preeclampsia, premature rupture of membranes, premature birth, neonatal asphyxia, and polyhydramnios were stable. CONCLUSIONS: Compared to standard care, telemedicine interventions can decrease the glycaemic levels of patients with GDM more effectively and reduce the risk of maternal and neonatal/foetal complications.

Association between circulating cell adhesion molecules and risk of type 2 diabetes: A meta-analysis.

BACKGROUND AND AIMS: Cell adhesion molecules (CAMs) are implicated in the initiation and progression of atherosclerosis, but their association with risk of type 2 diabetes remains inconsistent. This meta-analysis aimed to quantify this association with dose-response analysis in the general population without type 2 diabetes at baseline. METHODS: Prospective studies, investigating the association of circulating (plasma/serum) CAMs, such as intercellular adhesion molecule-1 (ICAM-1), E-selectin, vascular cell adhesion molecule-1 (VCAM-1), and P-selectin, with risk of type 2 diabetes, were included. The overall relative risks (RRs) with 95% confidence intervals (CIs) were calculated using a random-effects model. RESULTS: Sixteen datasets from 15 studies were included. The overall RR was 1.88 (95% CI 1.59 to 2.23) per 1-ln µg/ml increase in ICAM-1, and 2.44 (95% CI 1.90 to 3.12) per 1-ln µg/ml increase in E-selectin. These associations were log-linearly shaped (both pnon-linearity >0.05) and independent of traditional cardiovascular risk factors (all p < 0.05). ICAM-1 had comparable predictive ability as E-selectin (2.22 versus 2.66, p = 0.40). However, no significant association was observed for VCAM-1 (RR 1.20, 95% CI 0.73 to 1.98) or P-selectin (RR 1.01, 95% CI 0.64 to 1.59), and the added predictive value of circulating CAMs assessed by Integrated Discrimination Improvement to the basic prediction models was small (0.01 for ICAM-1, 0.003 for E-selectin, and 0.007 for VCAM-1). CONCLUSIONS: Elevated circulating CAMs, especially ICAM-1 and E-selectin, led to increased risk of type 2 diabetes in a dose-dependent manner, supporting the assumption that endothelial dysfunction contributes to the development of diabetes.

Association Between Cardiorespiratory Fitness and Risk of Heart Failure: A Meta-Analysis.

BACKGROUND: Evidence emerges that cardiorespiratory fitness (CRF) might be implicated in the development of heart failure (HF). This meta-analysis aimed to quantify the association between CRF exposed at baseline and HF risk with dose-response analysis and to assess whether CRF changes over time are correlated with alterations in HF risk. METHODS AND RESULTS: Cohort studies that assessed the association between CRF and risk of HF in subjects without baseline HF were included. Study-specific multivariate-adjusted relative risks (RRs) with 95% confidence intervals (CIs) were pooled using a random-effects model. Ten studies from 8 articles were included, enrolling 8987 incident HF cases from 154,598 participants. The RR of HF per 1-metabolic equivalent (MET) higher CRF at baseline was 0.82 (95% CI 0.80-0.84) in the overall population. The RRs were similar in men (0.82, 95% CI 0.80-0.85) and women (0.81, 95% CI 0.78-0.84), and remained minorly changed in patients with existing diabetes, hypertension, or cardiovascular disease at entry. No evidence of a nonlinear relationship between CRF at baseline and risk of HF was observed (Pnonlinearity = .18). The RR of HF per 1-MET increase in CRF over time was 0.79 (95% CI 0.67-0.93), and the measurement of CRF provided incremental value to the prediction of HF beyond conventional models. CONCLUSIONS: High or increased CRF resulted in reduced risk of HF in a dose-dependent manner, supporting the necessity to increase CRF to prevent HF in clinical practice.

Efficacy of Co-administration of Liuwei Dihuang Pills and Ginkgo Biloba Tablets on Albuminuria in Type 2 Diabetes: A 24-Month, Multicenter, Double-Blind, Placebo-Controlled, Randomized Clinical Trial.

Purpose: We investigated the effects of Traditional Chinese Medicine (TCM) on the occurrence and progression of albuminuria in patients with type 2 diabetes. Methods: In this randomized, double-blind, multicenter, controlled trial, we enrolled 600 type 2 diabetes without diabetic nephropathy (DN) or with early-stage DN. Patients were randomly assigned (1:1) to receive Liuwei Dihuang Pills (LWDH) (1.5 g daily) and Ginkgo biloba Tablets (24 mg daily) orally or matching placebos for 24 months. The primary endpoint was the change in urinary albumin/creatinine ratio (UACR) from baseline to 24 months. Results: There were 431 patients having UACR data at baseline and 24 months following-up in both groups. Changes of UACR from baseline to follow-up were not affected in both groups: -1.61(-10.24, 7.17) mg/g in the TCM group and -0.73(-7.47, 6.75) mg/g in the control group. For patients with UACR ≥30 mg/g at baseline, LWDH and Ginkgo biloba significantly reduced the UACR value at 24 months [46.21(34.96, 58.96) vs. 20.78(9.62, 38.85), P < 0.05]. Moreover, the change of UACR from baseline to follow-up in the TCM group was significant higher than that in the control group [-25.50(-42.30, -9.56] vs. -20.61(-36.79, 4.31), P < 0.05]. Conclusion: LWDH and Ginkgo biloba may attenuate deterioration of albuminuria in type 2 diabetes patients. These results suggest that TCM is a promising option of renoprotective agents for early stage of DN. Trial registration: The study was registered in the Chinese Clinical Trial Registry. (no. ChiCTR-TRC-07000037, chictr.org).

Association Between Cardiorespiratory Fitness and Risk of Type 2 Diabetes: A Meta-Analysis.

OBJECTIVE: This meta-analysis aimed to (1) quantify the association of cardiorespiratory fitness (CRF) with type 2 diabetes risk in the general population and statin users and (2) investigate the joint effects of CRF and fatness with type 2 diabetes risk. METHODS: Databases were searched for cohort studies reporting the association between CRF and type 2 diabetes risk. Summary hazard ratios (HRs) were obtained using random-effects models. RESULTS: Fifteen studies were included. The HRs of type 2 diabetes for every 1-metabolic equivalent increase in CRF were 0.90 (95% CI: 0.86-0.94) for the general population and 0.92 (95% CI: 0.87-0.97) for statin users, and the HRs were linearly shaped (both Pnonlinearity > 0.40). Compared with the nonstatin cohort, there was an increased risk of type 2 diabetes in statin users with the lowest and moderate CRF categories, but this was not present in the highest CRF category. The HR of type 2 diabetes for overweight/obesity-fit category versus normal weight-fit category was larger than that of the normal weight-unfit category versus the normal weight-fit category (Pinteraction   = 0.004). CONCLUSIONS: There was an inverse and dose-dependent association between CRF and type 2 diabetes risk. High CRF may eliminate the diabetogenic effect from statins, yet decreased body weight index seems superior in preventing type 2 diabetes.

Photo-responsive photonic crystals for broad wavelength shifts.

A facile method to realize photo-responsive inverse opal photonic crystal polymer (IOPP) films with an adjustable broad-wavelength-range photonic band gap (PBG) was demonstrated in this communication. When immersing the IOPP film in malachite green carbinol base (MGCB) solution, under light irradiation, the MGCB released hydroxide ions. In this way, optical signals were converted to chemical signals. As a result, the pH sensitive IOPP film expanded and the PBG changed. The band gap movement of the IOPP films with different monomer to cross-linker ratios was studied in this work.

Effects of atorvastatin on autophagy in skeletal muscles of diabetic rats.

AIMS/INTRODUCTION: Atorvastatin is usually used to decrease the amount of fatty substances in individuals with type 2 diabetes mellitus. However, it can cause side-effects, such as breakdown of skeletal muscle tissue. The present study focused on the effects of atorvastatin on autophagy of the skeletal muscles in diabetic rats. MATERIALS AND METHODS: Diabetes in rats in the diabetic (D) and atorvastatin (T) groups was induced using streptozotocin (65 mg/kg, intraperitoneal injection). Next, rats in the T group were treated with atorvastatin (10 mg/kg/day, intragastric administration), whereas rats in the control and D groups were given water. Additionally, the rats in T and D groups were fed a high-fat and high-sugar diet for 10 weeks. Subsequently, the histopathological changes, and expression levels of microtubule-associated protein 1 light chain 3 (LC3)-I/-II and p62 in the skeletal muscle specimens in the three groups were analyzed. RESULTS: Rats in the T group had reduced lipid droplets, cholesterol and low-density lipoprotein (P < 0.05) levels than those in the D group. Disordered atrophic myocytes, incrassated vascular walls and decreased cross-sectional area of type I fibers were found using hematoxylin-eosin and adenosine triphosphatase staining in the D and T groups. The messenger ribonucleic acid and protein levels of LC3-II and the LC3-II/LC3-I ratio were increased in the T group compared with those in the other groups (P < 0.05), whereas the protein level of p62 showed the opposite trend. CONCLUSIONS: Atorvastatin enhanced the autophagy level of skeletal muscles to decrease lipid deposition, which possibly exacerbated myopathy.

Facile fabrication of micro-grooves based photonic crystals towards anisotropic angle-independent structural colors and polarized multiple reflections.

In nature, many living organisms exhibit low-angle-dependent or even angle-independent structural colors for wide viewing angle, such as the blue skin of mandrill, feather of blue bird and shell of longhorn beetle, etc. To mimic these structural colors, based on periodic semicircular micro-grooved (PSMG) substrate, silica colloidal photonic crystals provide anisotropic angle-independent structural colors. The PSMG photonic crystals were fabricated by self-assembling monodispersed silica nanoparticles on a micro-grooved template, which can be easily prepared in large scale by a hot embossing method, and no additional materials are needed in the whole preparation process. The PSMG photonic crystals exhibit identical structural colors around the groove axis, whereas it is angle-dependent along the groove axis. In addition, this PSMG surface of photonic crystal also leads to color separation effect and monocolor polarization conversion. This system provides a facile and scalable means to prepare anisotropically angle-independent colloidal photonic crystal, which is considered important in applications in the field of anti-counterfeiting or the manufacture of monochromatic light reflector with wide viewing angles and other novel optical devices.

Performance of Fasting Plasma Glucose and Postprandial Urine Glucose in Screening for Diabetes in Chinese High-risk Population.

BACKGROUND: The conventional approaches to diabetes screening are potentially limited by poor compliance and laboratory demand. This study aimed to evaluate the performance of fasting plasma glucose (FPG) and postprandial urine glucose (PUG) in screening for diabetes in Chinese high-risk population. METHODS: Nine hundred and nine subjects with high-risk factors of diabetes underwent oral glucose tolerance test after an overnight fast. FPG, hemoglobin A1c, 2-h plasma glucose (2 h-PG), and 2 h-PUG were evaluated. Diabetes and prediabetes were defined by the American Diabetes Association criteria. The area under the receiver operating characteristic (ROC) curve was used to evaluate the diagnostic accuracy of 2 h-PUG, and the optimal cut-off determined to provide the largest Youden index. Spearman correlation was used for relationship analysis. RESULTS: Among 909 subjects, 33.4% (304/909) of subjects had prediabetes, and 17.2% (156/909) had diabetes. The 2 h-PUG was positively related to FPG and 2 h-PG (r = 0.428 and 0.551, respectively, both P < 0.001). For estimation of 2 h-PG ≥ 7.8 mmol/L and 2 h-PG ≥ 11.1 mmol/L using 2 h-PUG, the area under the ROC curve were 0.772 (95% confidence interval [CI ]: 0.738-0.806) and 0.885 (95% CI: 0.850-0.921), respectively. The corresponding optimal cut-offs for 2 h-PUG were 5.6 mmol/L and 7.5 mmol/L, respectively. Compared with FPG alone, FPG combined with 2 h-PUG had a higher sensitivity for detecting glucose abnormalities (84.1% vs. 73.7%, P < 0.001) and diabetes (82.7% vs. 48.1%, P < 0.001). CONCLUSION: FPG combined with 2 h-PUG substantially improves the sensitivity in detecting prediabetes and diabetes relative to FPG alone, and may represent an efficient layperson-oriented diabetes screening method.

Step counter use in type 2 diabetes: a meta-analysis of randomized controlled trials.

BACKGROUND: While step counter use has become popular among type 2 diabetes (T2D) patients, its effectiveness in increasing physical activity (PA) and improving glycemic control has been poorly defined. The aim of this meta-analysis of randomized controlled trials (RCTs) was to evaluate the association of step counter use with PA and glycemic control in T2D patients. METHODS: Articles were identified by searches of PubMed, Web of Science and Cochrane Library from January 1994 to June 2013. RCTs in the English language were included, if they had assessed the effectiveness of step counters as motivating and monitoring tools in T2D patients, with reported changes in steps per day (steps/d) or glycosylated hemoglobin A1c (HbA1c), or both. Data were independently collected by 2 authors and overall estimates were made by a random-effects model. RESULTS: Of the 551 articles retrieved, 11 RCTs were included. Step counter use significantly increased PA by 1,822 steps/d (7 studies, 861 participants; 95% confidence interval (CI): 751 to 2,894 steps/d) in patients with T2D. Step counter use with a PA goal showed a bigger increase in PA (weighted mean difference (WMD) 3,200 steps/d, 95% CI: 2,053 to 4,347 steps/d) than without (WMD 598 steps/d, 95% CI: -65 to 1,260 steps/d). Further subgroup analysis suggested step counter use with a self-set PA goal (WMD 2,816 steps/d, 95% CI: 1,288 to 4,344 steps/d) made no difference in increasing PA from a 10,000 steps/d goal (WMD 3,820 steps/d, 95% CI: 2,702 to 4,938 steps/d). However, no significant HbA1c change was observed by step counter use (10 studies, 1,423 participants; WMD 0.02%, 95% CI: -0.08% to 0.13%), either with (WMD 0.04%, 95% CI: -0.21% to 0.30%) or without a PA goal (WMD 0.01%, 95% CI: -0.10% to 0.13%). CONCLUSIONS: Step counter use is associated with a significant increase in PA in patients with T2D. However, evidence regarding its effect in improving glycemic control remains insufficient. TRIAL REGISTRATION: PROSPERO CRD42013005236.

Improved training tolerance by supplementation with α-Keto acids in untrained young adults: a randomized, double blind, placebo-controlled trial.

BACKGROUND: Exercise causes a variety of physiological and metabolic changes that can in turn reduce exercise tolerance. One of the potential mechanisms responsible for fatigue is "exercise-induced hyperammonemia". Previous studies have shown that supplementation with amino acids can increase training tolerance. The α-keto acids are biochemical analogs of amino acids and can be converted to amino acids through transamination, thus reducing the cellular ammonia level. This double blind, placebo-controlled study was designed to investigate the effects of α-keto acid supplementation (KAS) on training tolerance, training effect, and stress-recovery state. METHODS: Thirty-three untrained young male adults underwent four weeks of training (5 sessions/week; 30 minutes running at the individual anaerobic threshold followed by 3 x 3 minute sprints/each session). Throughout the 4 weeks of training and one week of recovery, subjects took α-ketoglutarate (AKG group, 0.2 g/kg/d, n = 9), branched-chain keto acids (BCKA group, 0.2 g/kg/d, n = 12) or isocaloric placebo (control group, n = 12) daily. RESULTS: The 4th week training volume, maximum power output and muscle torque were higher in the AKG group (175 ± 42 min, 412 ± 49 Watts and 293 ± 58 Newton meters, respectively, P<0.05) and the BCKA group (158 ± 35, 390 ± 29 and 273 ± 47, P<0.05) than in the control group (92 ± 70, 381 ± 67 and 233 ± 43). The general stress and emotional exhaustion as assessed by the rest-stress-questionnaire-sport after the 3rd week of training increased significantly in the control group (P<0.05), but not in the KAS groups. CONCLUSIONS: Under KAS, subjects could bear a higher training volume and reach a higher power output and peak muscle torque, accompanied by a better stress-recovery-state. Thus, KAS improves exercise tolerance and training effects along with a better stress-recovery state. Whether the improved training tolerance by KAS is associated with effects on ammonia homeostasis requires further observation.