756 research outputs found
Aggregation of microglia in 2D with string gradient weighted moving finite elements
Alzheimer's disease (AD) is a severe neurodegenerative disorder characterised by cognitive impairment and dementia. In the AD-affected brain, microglia cells are up-regulated and accumulate at senile plaques, the most prominent pathological feature of AD. In order to further study and predict the movement of activated microglia, we utilised their chemotactic properties. Specifically, we formulated the string gradient weighted moving finite element method for a system of partial differential equations in two dimensions, which includes nonlinear diffusion of a different variable found in chemotaxis models. The method was applied successfully to solve highly nonlinear chemorepulsion-chemorepellent models in two dimensions, and the results were compared with one-dimensional results found previously in the literature. We conclude that the string gradient weighted moving finite element method is easily applied to chemotaxis models, in particular movement and aggregation of microglia, resulting in the ability to study the models extended in two dimensions efficiently. Our study highlights the feasibility and power of mathematical modelling to advance our understanding of pathophysiological processes in neurodegenerative diseases, including AD
Age-dependent different action of curcumin in thyroid of rat.
The aging is associated with alterations in the hypothalamic-pituitary-thyroidal axis which can lead to hypothyreosis. Our previous investigations has shown that polyphenol curcumin can enhance the manifestation of hypothyreosis in rats simultaneous treated with propylthiouracil. The aim of the study was to investigate the relationship between age-related changes and curcumin action in the thyroid of old rats. To this end, morphometric and radioimmunological methods were used. The study was conducted on 3- and 18-month-old male Wistar rats. The experimental rats were treated daily for 30 days by gavage with 100 mg/kg b.w. of curcumin. There were observed age-related changes in morphology and endocrine function of the thyroid. It was increase in the percentages of large follicles and significant decrease in FT3 level in 18-month-old rats in comparison to 3-month ones. Curcumin treatment lead to significant increase in FT3 and FT4 levels in 3-month-old experimental rats, but the level of FT3 significantly decreased in 18-month-old rats after curcumin administration. Our results show that curcumin activity depends on the functional condition of the rat thyroid which changes with age. This compound exerts stimulatory influence on the secretory function of the thyroid gland in young rats, but has rather weak antithyroid activity in old animals
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Maternal metabolic factors during pregnancy predict early childhood growth trajectories and obesity risk: the CANDLE Study.
BackgroundWe investigated the individual and additive effects of three modifiable maternal metabolic factors, including pre-pregnancy overweight/obesity, gestational weight gain (GWG), and gestational diabetes mellitus (GDM), on early childhood growth trajectories and obesity risk.MethodsA total of 1425 mother-offspring dyads (953 black and 472 white) from a longitudinal birth cohort were included in this study. Latent class growth modeling was performed to identify the trajectories of body mass index (BMI) from birth to 4 years in children. Poisson regression models were used to examine the associations between the maternal metabolic risk factors and child BMI trajectories and obesity risk at 4 years.ResultsWe identified three discrete BMI trajectory groups, characterized as rising-high-BMI (12.6%), moderate-BMI (61.0%), or low-BMI (26.4%) growth. Both maternal pre-pregnancy obesity (adjusted relative risk [adjRR]â=â1.96; 95% confidence interval [CI]: 1.36-2.83) and excessive GWG (adjRRâ=â1.71, 95% CI: 1.13-2.58) were significantly associated with the rising-high-BMI trajectory, as manifested by rapid weight gain during infancy and a stable but high BMI until 4 years. All three maternal metabolic indices were significantly associated with childhood obesity at age 4 years (adjRR for pre-pregnancy obesityâ=â2.24, 95% CI: 1.62-3.10; adjRR for excessive GWGâ=â1.46, 95% CI: 1.01-2.09; and adjRR for GDMâ=â2.14, 95%â=â1.47-3.12). In addition, risk of rising-high BMI trajectory or obesity at age 4 years was stronger among mothers with more than one metabolic risk factor. We did not observe any difference in these associations by race.ConclusionMaternal pre-pregnancy obesity, excessive GWG, and GDM individually and jointly predict rapid growth and obesity at age 4 years in offspring, regardless of race. Interventions targeting maternal obesity and metabolism may prevent or slow the rate of development of childhood obesity
Optimality of broken extremals
In this paper we analyse the optimality of broken Pontryagin extremal for an
n-dimensional affine control system with a control parameter, taking values in
a k- dimensional closed ball. We prove the optimality of broken normal
extremals when n = 3 and the controllable vector fields form a contact
distribution, and when the Lie algebra of the controllable fields is locally
orthogonal to the singular locus and the drift does not belong to it. Moreover,
if k = 2, we show the optimality of any broken extremal even abnormal when the
controllable fields do not form a contact distribution in the point of
singularity.Comment: arXiv admin note: text overlap with arXiv:1610.0675
Participation in the special supplemental nutrition program for women, infants, and children is not associated with early childhood socioemotional development: Results from a longitudinal cohort study
AbstractSocioemotional development in early childhood has long-term impacts on health status and social outcomes, and racial and socioeconomic disparities in socioemotional skills emerge early in life. The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) is an early childhood nutrition intervention with the potential to ameliorate these disparities. Our objective was to assess the impact of WIC on early socioemotional development in a longitudinal study. We examined the association between WIC participation and scores on the Brief Infant Toddler Social Emotional Assessment (BITSEA) in 327 predominantly African American motherâchild dyads who were participants in the longitudinal Conditions Affecting Neurocognitive Development in Early Life (CANDLE) Study (Memphis, TN). To account for selection bias, we used within-child fixed effects to model the variability in each child's BITSEA scores over two measurement occasions (ages 12 and 24months). Final models were adjusted for time-varying characteristics including child age, maternal stress, mental health, child abuse potential, marital status, and food stamp participation. In fully adjusted models, we found no statistically significant effect of WIC on change in socioemotional development (β=0.22 [SD=0.39] and β=â0.58 [SD=0.79] for BITSEA Competence and Problem subdomains, respectively). Using rigorous methods and a longitudinal study design, we found no significant association between WIC and socioemotional development in a high needs population. This finding suggests that early childhood interventions that more specifically target socioemotional development are necessary if we are to reduce racial disparities in socioemotional skills and prevent poor social and health outcomes across the life course
Reâanalysis of late Quaternary dust mass accumulation rates in Serbia using new luminescence chronology for loessâpalaeosol sequence at Surduk
Despite numerous palaeoenvironmental investigations of loessâpalaeosol sequences across the Carpathian Basin, wellâdated highâresolution records are scarce. This paper presents a new highâresolution chronology for the loessâpalaeosol sequence at Surduk (Serbia), based on optically stimulated luminescence (quartz) and postâinfrared infrared stimulated luminescence (polymineral) dating. The presented record spans 53â19 ka, with primary loess deposition occurring after 52Âą2 ka, and differs from previously published chronologies that relied on less precise and now superseded dating protocols. Based on the new chronology, mass accumulation rates (MAR s) for Surduk were constructed and compared with sites in the Carpathian Basin. The results demonstrate that accumulation periods across this area are not consistent in timing or rates. The highâresolution dating strategy identifies a disturbance in sediment deposition that occurred after 45Âą2 ka and implies that site contains a hiatus. Finally, we show samples that failed routine dose recovery and preheat plateau tests, and had low fast ratios. Supported by bulk sample geochemical analysis it is proposed that a potential abrupt source shift, during the Last Glacial Maximum, may be the cause of the anomalous luminescence behaviour
Evaluating the sensitivity of hybridization-based epigenotyping using a methyl binding domain protein
Hypermethylation of CpG islands in gene promoter regions has been shown to be a predictive biomarker for certain diseases. Most current methods for methylation profiling are not well-suited for clinical analysis. Here, we report the development of an inexpensive device and an epigenotyping assay with a format conducive to multiplexed analysis.David H. Koch Institute for Integrative Cancer Research at MIT (First-year Graduate Fellowship)National Science Foundation (U.S.). Graduate Research FellowshipBurroughs Wellcome Fund (Career Award at the Scientific Interface)National Institute of Environmental Health Sciences (Grant P30-ES002109)Massachusetts Institute of Technology. James H. Ferry Fund for Innovation in Research Educatio
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