Although biomimetic designs are expected to play a key role in exploring future structural materials, facile fabrication of bulk biomimetic materials under ambient conditions remains a major ...challenge. Here, we describe a mesoscale "assembly-and-mineralization" approach inspired by the natural process in mollusks to fabricate bulk synthetic nacre that highly resembles both the chemical composition and the hierarchical structure of natural nacre. The millimeter-thick synthetic nacre consists of alternating organic layers and aragonite platelet layers (91 weight percent) and exhibits good ultimate strength and fracture toughness. This predesigned matrix-directed mineralization method represents a rational strategy for the preparation of robust composite materials with hierarchically ordered structures, where various constituents are adaptable, including brittle and heat-labile materials.
Sarcopenia was recently classified a geriatric syndrome and is a major challenge to healthy aging. Affected patients tend to have worse clinical outcomes and higher mortality than those without ...sarcopenia. Although there is general agreement on the principal diagnostic characteristics, initial thresholds for muscle mass, strength, and physical performance were based on data from populations of predominantly Europid ancestry and may not apply worldwide. The Asian Working Group for Sarcopenia (AWGS) issued regional consensus guidelines in 2014, and many more research studies from Asia have since been published; this review summarizes recent progress. The prevalence of sarcopenia estimated by the AWGS criteria ranges between 4.1% and 11.5% of the general older population; however, prevalence rates were higher in Asian studies that used European Working Group on Sarcopenia in Older People cut-offs. Risk factors include age, sex, heart disease, hyperlipidemia, daily alcohol consumption, and low protein or vitamin intake; physical activity is protective. Adjusting skeletal muscle mass by weight rather than height is better in showing the effect of older age in sarcopenia and identifying sarcopenic obesity; however, some Asian studies found no significant skeletal muscle loss, and muscle strength might be a better indicator. Although AWGS 2014 diagnostic cut-offs were generally well accepted, some may require further revision in light of conflicting evidence from some studies. The importance of sarcopenia in diverse therapeutic areas is increasingly evident, with strong research interest in sarcopenic obesity and the setting of malignancy. Pharmacologic interventions have been unsatisfactory, and the core management strategies remain physical exercise and nutritional supplementation; however, further research is required to determine the most beneficial approaches.
Severe vitamin D deficiency (SVDD) dramatically increases the risks of mortality, infections, and many other diseases. Studies have reported higher prevalence of vitamin D deficiency in patients with ...critical illness than general population. This multicenter retrospective cohort study develops and validates a score-based model for predicting SVDD in patients with critical illness.
A total of 662 patients with critical illness were enrolled between October 2017 and July 2020. SVDD was defined as a serum 25(OH)D level of < 12 ng/mL (or 30 nmol/L). The data were divided into a derivation cohort and a validation cohort on the basis of date of enrollment. Multivariable logistic regression (MLR) was performed on the derivation cohort to generate a predictive model for SVDD. Additionally, a score-based calculator (the SVDD score) was designed on the basis of the MLR model. The model's performance and calibration were tested using the validation cohort.
The prevalence of SVDD was 16.3% and 21.7% in the derivation and validation cohorts, respectively. The MLR model consisted of eight predictors that were then included in the SVDD score. The SVDD score had an area under the receiver operating characteristic curve of 0.848 95% confidence interval (CI) 0.781-0.914 and an area under the precision recall curve of 0.619 (95% CI 0.577-0.669) in the validation cohort.
This study developed a simple score-based model for predicting SVDD in patients with critical illness.
ClinicalTrials.gov protocol registration ID: NCT03639584. Date of registration: May 12, 2022.
To compare clinical characteristics of sarcopenia defined by the International Working Group on Sarcopenia (IWGS) and European Working Group on Sarcopenia in Older People (EWGSOP) criteria among ...older people in Taiwan.
A prospective population-based community study.
I-Lan County of Taiwan.
A total of 100 young healthy volunteers and 408 elderly people.
None.
Anthropometry, skeletal muscle mass measured by dual x-ray absorptiometry, relative appendicular skeletal muscle index (RASM), percentage skeletal muscle index (SMI), 6-meter walking speed, and handgrip strength.
The prevalence of sarcopenia was 5.8% to 14.9% in men and 4.1% to 16.6% in women according to IWGS and EWGSOP criteria by using RASM or SMI as the muscle mass indices. The agreement of sarcopenia diagnosed by IWGS and EWGSOP criteria was only fair by using either RASM or SMI (kappa = 0.448 by RASM, kappa = 0.471 by SMI). The prevalence of sarcopenia was lower by the IWGS definition than the EWGSOP definition, but it was remarkably lower by using RASM than SMI in both criteria. Overall, sarcopenic individuals defined by SMI were older, had a higher BMI but similar total skeletal muscle mass, and had poorer muscle strength and physical performance than nonsarcopenic individuals. However, by using RASM, sarcopenic individuals had less total skeletal muscle mass but similar BMI than nonsarcopenic individuals. Multivariable logistic regression showed that age was the strongest associative factor for sarcopenia in both IWGS and EWGSOP criteria. Obesity played a neutral role in sarcopenia when it is defined by using RASM, but significantly increased the risk of sarcopenia in both criteria by using SMI.
The agreement of sarcopenia defined by IWGS and EWGSOP was only fair, and the prevalence varied largely by using different skeletal muscle mass indices. Proper selections for cutoff values of handgrip strength, walking speed, and skeletal muscle indices with full considerations of gender and ethnic differences were of critical importance to reach the universal diagnostic criteria for sarcopenia internationally.
Association of frailty with adverse clinical outcomes has been reported in Western countries, but data from the Asian population are scarce. This study aimed to evaluate the epidemiology of frailty ...among community-dwelling middle-aged and elderly population and to explore its association with musculoskeletal health in Taiwan.
I-Lan Longitudinal Aging Study (ILAS) data were retrieved for this study. Frailty was defined by the Fried's criteria; a comparison of demographic characteristics, physical performance, and body composition, including skeletal muscle mass and bone mineral density (BMD), as well as recent falls, history of hip fractures and the functional status of subjects with different frailty statuses were accomplished.
Overall, the data of 1,839 participants (mean age: 63.9±9.3 years, male 47.5%) were obtained for analysis. The prevalence of pre-frailty was 42.3% in men and 38.8% in women, whereas the prevalence of frailty was 6.9% and 6.7% in men and women, respectively. Frailty was significantly associated with older age, the male gender, larger waist circumference, lower skeletal muscle index, lower hip BMD, poorer physical function, poorer nutritional status, and poorer cognitive function. Also, frailty was significantly associated with osteoporosis (OR: 7.73, 95% CI: 5.01-11.90, p<0.001), history of hip fractures (OR: 8.66, 95% CI: 2.47-30.40, p = 0.001), and recent falls (O.R: 2.53, 95% CI: 1.35-4.76, p = 0.004).
Frailty and pre-frailty, in Taiwan, was closely associated with recent falls, history of hip fractures and osteoporosis among community-dwelling people 50 years of age and older. Furthermore, frailty intervention programs should take an integrated approach towards strengthening both and muscle mass, as well as prevention of falls.
To characterize the hot deformation behavior of commonly used aluminum alloy, a homogeneous Al–Mg–Si–Mn–Cr alloy was analyzed by thermal simulation test at deformation temperature range of 653–803 K ...and strain rate range of 0.01–10 s
−1
. The flow stresses were predicted by modified Johnson–Cook model, modified Zerilli–Armstrong model and strain-compensated Arrhenius model. The results show that the three models are able to predict the flow behavior of the alloy. Strain-compensated Arrhenius model has the best simulation ability in predicting flow stresses, while the modified Johnson–Cook model has lower prediction accuracy and the modified Zerilli–Armstrong model has poorer predictive ability at low strain rates. Microstructure evolution shows that subgrain boundaries form at original grain boundaries at first, moving toward to the center of the deformed grains. The dislocation density decreases, while the number and the size of subgrains increase with the decreasing Zener–Hollomon (
Z
) parameter. Both dynamic recovery (DRV) and dynamic recrystallization take place in hot deformation process. DRV is considered to be the primary dynamic softening mechanism throughout the entire hot deformation range. Continuous dynamic recrystallization and discontinuous dynamic recrystallization operate concurrently at low strain rates and high temperatures. The relationship of subgrain size and predicted flow stress is presented. Moreover, activation volume is introduced to reveal the thermal activation mechanism during hot deformation.
Background
Myostatin is a negative regulator of muscle growth but the relationship between serum myostatin levels and muscle mass is unclear. This study investigated the association between serum ...myostatin levels and skeletal muscle mass among healthy older community residents in Taiwan, to evaluate the potential of serum myostatin as a biomarker for diagnosing sarcopenia and/or evaluating the effect of its treatment.
Methods
Study data were excerpted from a random subsample of the I‐Lan Longitudinal Aging Study population. Serum myostatin levels were determined and categorized into tertiles (low, medium, high). Relative appendicular skeletal muscle mass (RASM) was calculated as appendicular lean body mass by dual‐energy X‐ray absorptiometry divided by height squared (kg/m2). Low muscle mass was defined as recommended by the Asian Working Group for Sarcopenia.
Results
The analytic study sample comprised 463 adults (mean age: 69.1 years; 49.5% men). Compared with subjects with normal RASM, those with lower RASM were older and frailer, with significantly higher prevalence of malnutrition, lower serum dehydroepiandrosterone (DHEA) levels, and were more likely to have low serum myostatin status. Multivariable logistic regression analysis showed that male sex (OR 3.60, 95% CI 1.30–9.92), malnutrition (OR 4.39, 95% CI 1.56–12.36), DHEA (OR 0.99, 95% CI 0.99–1.00), and low myostatin (OR 3.23, 95% CI 1.49–7.01) were all independent risk factors for low RASM (all P < 0.05). In men, DHEA (OR 0.99, 95% CI 0.98–1.00) and low myostatin (OR 4.89, 95% CI 1.79–13.37) were significantly associated with low RASM (both P < 0.05); however, only malnutrition was associated with low RASM in women (OR 13.59, 95% CI 2.22–83.25, P < 0.05).
Conclusions
Among healthy community‐living older adults, low serum myostatin levels were associated with low skeletal muscle mass in men, but not in women. Our results do not support using serum myostatin levels to diagnose sarcopenia, or to monitor how it responds to treatments. Further research is needed to understand why men apparently differ from women in the interrelationship between their myostatin levels and muscle mass.
A novel method is developed for constructing well-defined N-doped graphdiyne (GDY) nanostructures. This method can effectively tune the N-configurations (pyridinic N and triazine-like N cluster), ...N-content, and porous structures of GDYs, indicating good controllability. The N-configurations and structure of GDYs are well confirmed by the X-ray photoelectron spectrometer measurements, nitrogen absorption measurements and neutron pair distribution function (PDF), respectively. The as-prepared GDYs can be assembled into high-performance two-electrode supercapacitors with specific capacitance high up to 250Fg−1, delivering an energy density of 8.66Whkg−1 and power density of 19.3kWkg−1; the well-defined N-configuration in GDYs offers us an opportunity to understand the controversial nitrogen role in catalyzing the oxygen reduction reaction in sp2 carbons. Importantly, this method for creating well-defined N-doped GDYs may widely extend the GDY materials for new energy fields.
A novel method is developed for efficiently constructing well-defined N-doped graphdiyne (GDY) with microporous structure. The as-prepared GDYs have high surface area and 3D continuousness, and can be applied as promising electrodes for high-performance symmetric supercapacitors (250Fg−1) and metal-free catalysts of oxygen reduction reaction. Display omitted
•A novel method is developed for constructing well-defined N-doped graphdiyne (GDY) with microporous structure.•N-configurations, N-content, and porous structures of GDYs can be effectively tuned.•The GDYs can be assembled into high-performance two-electrode supercapacitors with high specific capacitance.•This method for creating well-defined N-doped GDYs may extend the GDY materials for new energy fields.
Sarcopenia, a newly recognized geriatric syndrome, is characterized by age-related decline of skeletal muscle plus low muscle strength and/or physical performance. Previous studies have confirmed the ...association of sarcopenia and adverse health outcomes, such as falls, disability, hospital admission, long term care placement, poorer quality of life, and mortality, which denotes the importance of sarcopenia in the health care for older people. Despite the clinical significance of sarcopenia, the operational definition of sarcopenia and standardized intervention programs are still lacking. It is generally agreed by the different working groups for sarcopenia in the world that sarcopenia should be defined through a combined approach of muscle mass and muscle quality, however, selecting appropriate diagnostic cutoff values for all the measurements in Asian populations is challenging. Asia is a rapidly aging region with a huge population, so the impact of sarcopenia to this region is estimated to be huge as well. Asian Working Group for Sarcopenia (AWGS) aimed to promote sarcopenia research in Asia, and we collected the best available evidences of sarcopenia researches from Asian countries to establish the consensus for sarcopenia diagnosis. AWGS has agreed with the previous reports that sarcopenia should be described as low muscle mass plus low muscle strength and/or low physical performance, and we also recommend outcome indicators for further researches, as well as the conditions that sarcopenia should be assessed. In addition to sarcopenia screening for community-dwelling older people, AWGS recommends sarcopenia assessment in certain clinical conditions and healthcare settings to facilitate implementing sarcopenia in clinical practice. Moreover, we also recommend cutoff values for muscle mass measurements (7.0 kg/m(2) for men and 5.4 kg/m(2) for women by using dual X-ray absorptiometry, and 7.0 kg/m(2) for men and 5.7 kg/m(2) for women by using bioimpedance analysis), handgrip strength (<26 kg for men and <18 kg for women), and usual gait speed (<0.8 m/s). However, a number of challenges remained to be solved in the future. Asia is made up of a great number of ethnicities. The majority of currently available studies have been published from eastern Asia, therefore, more studies of sarcopenia in south, southeastern, and western Asia should be promoted. On the other hand, most Asian studies have been conducted in a cross-sectional design and few longitudinal studies have not necessarily collected the commonly used outcome indicators as other reports from Western countries. Nevertheless, the AWGS consensus report is believed to promote more Asian sarcopenia research, and most important of all, to focus on sarcopenia intervention studies and the implementation of sarcopenia in clinical practice to improve health care outcomes of older people in the communities and the healthcare settings in Asia.
Insulin resistance (IR) is a known risk factor for cardiovascular disease (CVD) in non-diabetic patients through the association of hyperglycemia or associated metabolic factors. The triglyceride ...glucose (TyG) index, which was defined by incorporating serum glucose and insulin concentrations, was developed as a surrogate marker of insulin resistance. We aimed to investigate the association between the TyG index and the early phase of subclinical atherosclerosis (SA) between the sexes.
The I-Lan Longitudinal Aging Study (ILAS) enrolled 1457 subjects aged 50-80 years. For each subject, demographic data and the TyG index {lnfasting triglyceride (mg/dL) × fasting plasma glucose (mg/dL)/
} were obtained. Patients were further stratified according to sex and the 50th percentile of the TyG index (≥ 8.55 or < 8.55). SA was defined as the mean carotid intima-media thickness (cIMT) at the 75th percentile of the entire cohort. Demographic characteristics and the presence of SA were compared between the groups. Logistic regression analysis was performed to assess the relationship between TyG index and SA.
Patients with a higher TyG index (≥ 8.55) had a higher body mass index (BMI), hypertension (HTN) and diabetes mellitus (DM). They had higher lipid profiles, including total cholesterol (T-Chol) and low-density lipoprotein (LDL), compared to those with a lower TyG index (< 8.55). Gender disparity was observed in non-diabetic women who had a significantly higher prevalence of SA in the high TyG index group than in the low TyG index group. In multivariate logistic regression analysis, a high TyG index was independently associated with SA in non-diabetic women after adjusting for traditional risk factors adjusted odds ratio (OR): 1.510, 95% CI 1.010-2.257, p = 0.045 but not in non-diabetic men. The TyG index was not associated with the presence of SA in diabetic patients, irrespective of sex.
A high TyG index was significantly associated with SA and gender disparity in non-diabetic patients. This result may highlight the need for a sex-specific risk management strategy to prevent atherosclerosis.
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