Muscle density is an independent risk factor of second hip fracture: a prospective cohort study.

BACKGROUND: Patients with a first hip fracture are at high risk of fracturing their other hip. Despite this, preventive therapy is often not given. Because little is known about specific risk factors of a second hip fracture, we investigated the association with areal bone mineral density (aBMD), muscle size, and density. We also investigated whether muscle parameters predict the risk of a contralateral fracture independently of aBMD. METHODS: Three groups were included, one without hip fracture (a subcohort of the China Action on Spine and Hip Status study), one with a first, and one with a second hip fracture. Subjects with fractures were recruited from the longitudinal Chinese Second Hip Fracture Evaluation (CSHFE). Computed tomography scans of CSHFE patients, which were obtained immediately following their first fracture, were used to measure cross-sectional area and density of the gluteus maximus (G.MaxM) and gluteus medius and minimus (G.Med/MinM) muscles. Computed tomography X-ray absorptiometry was used to measure aBMD of the contralateral femur. Median follow-up time to second fracture was 4.5 years. Cox proportional hazards models were used to compute hazard ratios (HR) of second hip fracture risk in subjects with a first hip fracture. Multivariate logistic regressions were used to compare odds ratios (OR) for the risk of a first and second hip fracture. RESULTS: Three hundred and one participants (68.4 ± 6.1 years, 64% female) without and 302 participants (74.6 ± 9.9 years, 71% female) with a first hip fracture were included in the analysis. Among the latter, 45 (79.2 ± 7.1 years) sustained a second hip fracture. ORs for first hip fracture were significant for aBMD and muscle size and density. ORs for a second fracture were smaller by a factor of 3 to 4 and no longer significant for femoral neck (FN) aBMD. HRs for predicting second hip fracture confirmed the results. G.Med/MinM density (HR, 1.68; CI, 1.20-2.35) and intertrochanter aBMD (HR, 1.62; CI, 1.13-2.31) were the most significant. FN aBMD was not significant. G.Med/MinM density remained significant for predicting second hip fracture after adjustment for FN (HR, 1.66; Cl, 1.18-2.30) or total hip aBMD (HR, 1.50; 95% Cl, 1.04-2.15). CONCLUSIONS: Density of the G.Med/MinM muscle is an aBMD independent predictor of the risk of second hip fracture. Intertrochanteric aBMD is a better predictor of second hip fracture than FN and total hip aBMD. These results may trigger a paradigm shift in the assessment of second hip fracture risk and prevention strategies.

Enhanced electrochemical degradation of 2,4-dichlorophenol with the assist of hydrochar.

Effective treatment of 2,4-dichlorophenol (2,4-DCP) in wastewater is essential, as it could pose great threat to the environment. A hydrothermal biochar (hydrochar) was used to assist the electrochemical oxidation treatment of 2,4-DCP. The removal of 2,4-DCP using hydrochar in anode and cathode area with and without proton exchange membrane (PEM) under 3-9 V of electrolysis was investigated. Enhanced 2,4-DCP degradation in the anode area was achieved compared with the adsorption or electrolysis alone. The highest 2,4-DCP removal (∼76%) was obtained using the hydrochar in the anode area with PEM under 9 V. The mechanism for the 2,4-DCP removal during the electrolysis included adsorption by hydrochar and electrochemical degradation by the reactive oxygen species (ROS) generated by the electrode as well as the persistent free radicals (PFR) on hydrochar. The OH produced from anode was the predominant ROS contributing to the 2,4-DCP degradation under 9 V of electrolysis.

Assessment of health inequality between urban-to-urban and rural-to-urban migrant older adults in China: a cross-sectional study.

BACKGROUND: Many studies focused on health inequality between migrant older adults and local older adults, while few study concerned the health inequalities between urban-to-urban and rural-to-urban migrant older adults. This study aimed to compare physical health and mental health between these two groups in Hangzhou, Zhejiang Province, China, and to explore the relationship between cognitive social capital, social integration and health among migrant older adults. METHODS: A two-stage stratified sampling method was employed to recruit participants from May to August 2013 in Hangzhou. Measurement data were compared with student's t-tests and multivariate analysis of variance (MANOVA). Multiple linear regression was adopted in this study. RESULTS: A total of 1000 of participants who met the inclusion criteria were analyzed, consisting of 527 (52.7%) urban-to-urban and 473 (47.3%) rural-to-urban migrant older adults. There were no statistically significant difference in physical health and mental health between urban-to-urban and rural-to-urban groups on the whole. However, urban-to-urban migrant older adults had a higher reciprocity and social integration than did in rural-to-urban group (13.36 vs. 12.50, p < 0.01; 40.07 vs. 38.50, p < 0.01). And both of cognitive social capital and social integration were positively related to physical health (social reciprocity: t = 6.69, p < 0.01; social trust: t = 3.27, p < 0.01; social integration: t = 5.66, p < 0.01) and mental health (social reciprocity: t = 4.49, p < 0.01; social trust: t = 5.15, p < 0.01; social integration: t = 10.02, p < 0.01). Overall, the female, widowed, and the oldest among migrant older adults had a worse health. CONCLUSIONS: Social capital and social integration were played important roles in health of migrant older adults. The female rural-to-urban migrant older adults, those aged over 70 years, and older adults who were not in marriage should be especially concerned in health policy making.

Prenatal exposure to diesel exhaust PM2.5 programmed non-alcoholic fatty liver disease differently in adult male offspring of mice fed normal chow and a high-fat diet.

Air pollution is one of the leading preventable threats to public health. Emerging evidence indicates that exposure to environmental stressors is associated with abnormal foetal development. However, how prenatal exposure to diesel exhaust PM2.5 (DEP) predisposes adult offspring to the development of non-alcoholic fatty liver disease (NAFLD) remains unclear. To examine this, C57BL/6J mice were exposed to DEP or a vehicle before conception and during pregnancy and fed normal chow or a high-fat diet. Then, the hepatic fatty accumulation in the adult male offspring and possible molecular mechanisms were assessed. Our data showed that prenatal exposure to DEP on normal chow led to hepatic steatosis in adult male offspring with normal liver function. However, prenatal DEP exposure relieved the hepatic steatosis and liver function in offspring of mice fed a high-fat diet. Furthermore, prenatal exposure to DEP on normal chow increased lipogenesis and worsened fatty acid oxidation. The counteractive effect of prenatal DEP exposure on high-fat-diet-induced hepatic steatosis was produced through upregulated adenosine 5'-monophosphate-activated protein kinase, and this improved lipogenesis and fatty acid oxidation. Collectively, prenatal exposure to DEP programmed the development of NAFLD differently in the adult male offspring of mice fed normal chow and a high-fat diet, showing the pleotrophic effects of exposure to adverse environmental factors in early life.

JNK activation-mediated nuclear SIRT1 protein suppression contributes to silica nanoparticle-induced pulmonary damage via p53 acetylation and cytoplasmic localisation.

The molecular mechanism by which silica nanoparticles (SiNPs) cause cellular apoptosis in the respiratory system is unclear. Silent mating type information regulation 2 homolog 1 (SIRT1), an NAD+-dependent deacetylase, mediates the pulmonary damage associated with several environmental stimuli. However, the SIRT1 response to SiNP exposure and its role in SiNP-triggered pulmonary toxicity remains unknown. Here, SiNPs were found to downregulate nuclear rather than cytosolic SIRT1 protein levels in human bronchial epithelial cells (BEAS-2b). They did not affect SIRT1 gene expression but accelerated SIRT1 protein degradation via c-Jun N-terminal kinase (JNK) activation. SiNP-mediated SIRT1 suppression markedly increased tumour protein 53 (p53) acetylation and cytoplasmic localisation, leading to the release of cytochrome c from mitochondria to the cytosol. SIRT1 overexpression dramatically decreased p53 acetylation and its cytoplasmic localisation, and this was accompanied by attenuated apoptosis in SiNP-exposed cells. Finally, SiNPs suppressed SIRT1 and stimulated apoptosis in the lung tissues of mice. In summary, SiNPs downregulate nuclear SIRT1 via JNK activation-mediated protein degradation, which leads to apoptosis via p53 acetylation and cytoplasmic localisation. These findings improve our understanding of SiNP-induced pulmonary damage and molecular targets to antagonise it.

Comparison of access to health services among urban-to-urban and rural-to-urban older migrants, and urban and rural older permanent residents in Zhejiang Province, China: a cross-sectional survey.

BACKGROUND: While much literature reported the access of Chinese older migrants to health services, little was known about the differences among sub-groups of older adults, including urban-to-urban and rural-to-urban migrants, and urban and rural permanent residents. This study aimed to examine the access of these four groups to health services in Zhejiang Province, China and provide an evidence for the development of health services policies. METHODS: A cross-sectional survey was conducted in community-dwelling older adults (aged 60 years or above) in 2013. Participants were recruited by random sampling. Demographic information and access to health services for the elderly populations were obtained via interviews using a self-designed structured questionnaire. Pearson's chi-square tests and Cochran-Mantel-Haenszel (CMH) tests were performed to examine the differences in access to health services among the four groups. Binary logistic regression was conducted to explore the associations of participants' visits to doctors with their group status after controlling confounding factors. RESULTS: The two-week hospital visiting rates were significantly lower in migrants (55.56% in rural-to-urban and 62.50% in urban-to-urban) than that in urban and rural permanent residents (67.40 and 82.25%, respectively; p < 0.01). The majority of older adults who received a diagnosis indicating need for hospital treatment accepted the treatment, with no significant difference among the four groups after controlling for health service need (χ2 = 7.08, p = 0.07). On the other hand, 30.05% of the older adults did not visit a doctor when they got ailments in the past 2 weeks prior to the survey, and 16.42% (33/201) did not receive hospital treatment after receiving a diagnosis indicating need for hospital treatment. Factors including age, marital status, educational attainment, major financial source, and living with family members did not influence health services use. CONCLUSIONS: Targeted social and health policies integrating the strengths of government, society and families should be implemented to further improve health services use for different groups of older adults.

Two-dimensional grid optimization for sedimentation velocity analysis in the analytical ultracentrifuge.

Sedimentation velocity experiments performed in the analytical ultracentrifuge are modeled using finite-element solutions of the Lamm equation. During modeling, three fundamental parameters are optimized: the sedimentation coefficients, the diffusion coefficients, and the partial concentrations of all solutes present in a mixture. A general modeling approach consists of fitting the partial concentrations of solutes defined in a two-dimensional grid of sedimentation and diffusion coefficient combinations that cover the range of possible solutes for a given mixture. An increasing number of grid points increase the resolution of the model produced by the subsequent analysis, with denser grids giving rise to a very large system of equations. Here, we evaluate the efficiency and resolution of several regular grids and show that traditionally defined grids tend to provide inadequate coverage in one region of the grid, while at the same time being computationally wasteful in other sections of the grid. We describe a rapid and systematic approach for generating efficient two-dimensional analysis grids that balance optimal information content and model resolution for a given signal-to-noise ratio with improved calculation efficiency. These findings are general and apply to one- and two-dimensional grids, although they no longer represent regular grids. We provide a recipe for an improved grid-point spacing in both directions which eliminates unnecessary points, while at the same time providing a more uniform resolution that can be scaled based on the stochastic noise in the experimental data.

Associations of urinary polycyclic aromatic hydrocarbons with bone mass density and osteoporosis in U.S. adults, NHANES 2005-2010.

Polycyclic aromatic hydrocarbons (PAHs) are environmental endocrine disruptors, which may modify the bone mineralization. However, epidemiological evidences on this issue were scant. We aimed to investigate the associations of PAHs with bone mass density (BMD) and osteoporosis based on a nationally-representative sample from general U.S. POPULATION: Data utilized were extracted from the 2005-2010 National Health and Nutrition Examination Survey (NHANES). Nine urinary PAHs (U-PAHs) metabolites were measured as exposure biomarkers. Associations of specific U-PAHs with BMD and osteoporosis were estimated by multivariable adjusted linear regression models and logistic regression models, respectively. Compared with women at the first tertiles, those at the third tertiles of 1-Hydroxynapthalene, 2-Hydroxyfluorene, 3-Hydroxyphenanthrene, 2-Hydroxyphenanthrene and 9-Hydroxyfluorene had significantly decreased BMD levels [coefficient (ß) = -0.023 to -0.014, p < 0.05] or increased likelihoods of osteoporosis [odds ratios (ORs) = 1.86 to 3.36, p < 0.05] at different bone sites. Whereas, elevated BMD levels (ß = 0.021, p < 0.05) at trochanter and decreased likelihoods of osteoporosis (OR = 0.33, p < 0.05) at intertrochanter were observed among women at the second tertiles of 1-Hydroxypyrene and 2-Hydroxynapthalene, respectively. Similar results were found for all the population, i.e., combination of men and women. Most of the significant associations disappeared among adult men only. Furthermore, Associations between U-PAHs and BMD were stronger for postmenopausal women when compared with premenopausal group. In conclusion, associations of U-PAHs with BMD and osteoporosis varied by specific U-PAHs and bone sites, as well as menopausal status and genders in U.S. adults.

Relationships between acrylamide and glycidamide hemoglobin adduct levels and allergy-related outcomes in general US population, NHANES 2005-2006.

BACKGROUND: Acrylamide-induced immunotoxicity and allergic dermatitis have been reported in animal experiments and clinical reports, respectively. However, epidemiological evidence from the general population is limited. OBJECTIVES: The purpose of the present study was to estimate the associations between acrylamide exposure and allergy-related outcomes in the general US population. METHODS: A total of 6982 subjects were selected from the National Health and Nutrition Examination Survey 2005-2006 (NHANES). Internal exposure was measured by the hemoglobin adducts of acrylamide (HbAA) and its metabolite glycidamide (HbGA). Allergy-related outcomes including asthma, hay fever, allergy, itchy rash, sneeze, wheeze and eczema were obtained by self-administered questionnaires. Allergic sensitization was assessed by the total immunoglobulin E (IgE) levels. The associations of HbAA and HbGA quartiles with allergy-related outcomes were calculated using logistic regression models with multivariable adjustments. Analyses were additionally stratified according to age, gender and serum cotinine levels. RESULTS: When setting quartile 1 of HbAA as reference, the odds ratios (ORs) [95% confidence intervals (CIs)] of quartile 2 to 4 for eczema were 1.18 (0.79-1.76), 1.14 (0.73-1.78) and 1.58 (1.14-2.18), respectively (ptrend = 0.002). Individuals at the highest quartile of HbGA had significantly elevated likelihoods of itchy rash (OR = 1.37, 95% CI = 1.02-1.83, ptrend = 0.032) and eczema (OR = 1.45, 95% CI = 1.06-1.97, ptrend = 0.044). The stratification analyses indicated various results in different subgroups. CONCLUSIONS: This study indicated significant associations between HbAA and HbGA levels and the likelihoods of allergy-related outcomes in the general US population, depending on age, gender and smoke exposure status. These findings suggested potential public health concerns for the widespread exposure to acrylamide.

Social capital and depression: evidence from urban elderly in China.

OBJECTIVES: To study the relationship between social capital and depression among older adults from urban China and the mediating effect of social support on the influence of social capital on depression. METHODS: Data were collected from face-to-face interviews targeting older adults (N = 928, response rate = 68.1%) aged over 60 years residing in Hangzhou, China, in 2013. Indicators of social capital included both cognitive (trust and reciprocity) and structural (social network and social participation) aspects. The dependent variable depression was measured by the Geriatric Depression Scale, social support was measured by the Multidimensional Scale of Perceived Social Support, and sociodemographic variables (age, education, and household income) and physical function were controlled for analysis. The data were analyzed by factor analysis and a hierarchical regression model. RESULTS: Trust, reciprocity, and social network were significantly associated with geriatric depression after controlling. Social participation was not correlated with geriatric depression. Social support partially mediated the relationships between social capital and geriatric depression. CONCLUSION: This study provides new evidence that social capital effectively mediates geriatric depression directly and indirectly. The intervention of social capital on depression should therefore consider the two pathways. Future longitudinal studies should help further understand the mechanisms linking social capital and depression.

A two-dimensional spectrum analysis for sedimentation velocity experiments of mixtures with heterogeneity in molecular weight and shape.

We report a model-independent analysis approach for fitting sedimentation velocity data which permits simultaneous determination of shape and molecular weight distributions for mono- and polydisperse solutions of macromolecules. Our approach allows for heterogeneity in the frictional domain, providing a more faithful description of the experimental data for cases where frictional ratios are not identical for all components. Because of increased accuracy in the frictional properties of each component, our method also provides more reliable molecular weight distributions in the general case. The method is based on a fine grained two-dimensional grid search over s and f/f (0), where the grid is a linear combination of whole boundary models represented by finite element solutions of the Lamm equation with sedimentation and diffusion parameters corresponding to the grid points. A Monte Carlo approach is used to characterize confidence limits for the determined solutes. Computational algorithms addressing the very large memory needs for a fine grained search are discussed. The method is suitable for globally fitting multi-speed experiments, and constraints based on prior knowledge about the experimental system can be imposed. Time- and radially invariant noise can be eliminated. Serial and parallel implementations of the method are presented. We demonstrate with simulated and experimental data of known composition that our method provides superior accuracy and lower variance fits to experimental data compared to other methods in use today, and show that it can be used to identify modes of aggregation and slow polymerization.

Biodegradable thermogelling hydrogel of P(CL-GL)-PEG-P(CL-GL) triblock copolymer: degradation and drug release behavior.

Degradation and drug release behavior of thermogelling hydrogel of poly(epsilon-caprolactone-co-glycolide)-poly(ethylene glycol)-poly(epsilon-caprolactone-co-glycolide) [P(CL-GL)-PEG-P(CL-GL) (1880-1540-1880)] triblock copolymer were investigated. The copolymer aqueous solution (25 wt%) underwent sol-gel transition at 35 degrees C as the temperature increased and formed a stable gel at body temperature. After incubation in PBS buffer solution (0.1 M) at 37 degrees C, the gel degraded completely into a viscous liquid at 14th week. Chemical microstructural analysis of the degraded samples by (1)H-NMR revealed the degradation occurring mainly on the glycolyl sequences of the copolymer. The pH value of the gel buffer solution maintained neutral during the initial 8 weeks, which may be beneficial for the preservation of activity of pH-sensitive drugs. Incorporation of drugs into the gel was formulated at room temperature without the use of any organic solvent. The gel formed a controlled release depot with delivery times of 12, 32, and 25 days for isoniazid, rifampicin and bovine serum albumin, respectively. Controlled release of hydrophobic rifampicin was achieved with insignificant burst effect due to the distribution of the drug mainly in the hydrophobic polyester regions of the gel.

Modeling analytical ultracentrifugation experiments with an adaptive space-time finite element solution for multicomponent reacting systems.

We describe an extension of the adaptive space-time finite element method (ASTFEM) used in the solution of the Lamm equation to the case of multicomponent reacting systems. We use an operator splitting technique to decouple the sedimentation-diffusion process from the reaction process. The former is solved with an ASTFEM approach based on the Petrov-Galerkin method and on adaptive moving grids, and the latter is solved with the implicit midpoint Euler's method. Our solution can effectively eliminate the sedimentation errors for each component or species involved in the reaction, and it is free from oscillation near the cell bottom. It offers second-order accuracy, and guarantees conservation of mass without any additional postprocessing, and it permits modeling of multicomponent, equilibrating systems where the reaction rate can be kinetically controlled between an instantaneous reaction and a noninteracting mixture. The proposed ASTFEM solution provides improved efficiency and accuracy compared to classical approaches, especially when medium-sized and large molecules are modeled.

Modeling analytical ultracentrifugation experiments with an adaptive space-time finite element solution of the Lamm equation.

Analytical ultracentrifugation experiments can be accurately modeled with the Lamm equation to obtain sedimentation and diffusion coefficients of the solute. Existing finite element methods for such models can cause artifactual oscillations in the solution close to the endpoints of the concentration gradient, or fail altogether, especially for cases where somega(2)/D is large. Such failures can currently only be overcome by an increase in the density of the grid points throughout the solution at the expense of increased computational costs. In this article, we present a robust, highly accurate and computationally efficient solution of the Lamm equation based on an adaptive space-time finite element method (ASTFEM). Compared to the widely used finite element method by Claverie and the moving hat method by Schuck, our ASTFEM method is not only more accurate but also free from the oscillation around the cell bottom for any somega(2)/D without any increase in computational effort. This method is especially superior for cases where large molecules are sedimented at faster rotor speeds, during which sedimentation resolution is highest. We describe the derivation and grid generation for the ASTFEM method, and present a quantitative comparison between this method and the existing solutions.