6,332 publications from this institution
Lower melatonin secretion was independently associated with a higher risk of developing type 2 diabetes. Further research is warranted to assess if melatonin secretion is a modifiable risk factor for diabetes within the general population.
Introduction: Healthful dietary patterns are associated with lower cardiometabolic risk, but the underlying mechanisms are not fully understood. Hypothesis: Healthful dietary patterns share widespread metabolomic signatures that are associated with altered risk of cardiometabolic diseases. Methods: We analyzed data from 2976 adult participants free of diabetes and CVD in the Hispanic Community Health Study/Study of Latinos. Scores of three USDA recommended dietary patterns, Healthy Eating Index (HEI)-2015, alternative Mediterranean diet (aMED), and healthful plant-based dietary index (hPDI) were calculated by averaging two 24-hour dietary recalls. Fasting serum metabolomics was performed using an untargeted approach. Dietary pattern associated metabolite modules were clustered using a weighted correlation network analysis, and their associations with 6-year incidence of diabetes and hypertension were further examined. Results: Of 624 known metabolites identified, some were uniquely associated with a single dietary score, while 51 metabolites were significantly associated with all dietary scores ( Figure A ). Eight metabolite modules were clustered based on 184 dietary pattern-related metabolites. Each dietary score was associated with one unique metabolite module, and two modules composed of antioxidants or polyunsaturated fatty acids (PUFA) were associated with all dietary scores ( Figure B ). After multivariable adjustment for demographics, socioeconomics, lifestyles, and BMI, the antioxidant module was significantly associated with lower risk of diabetes (per SD, relative risk (RR) = 0.80 [95% CI 0.69-0.96]) and risk of hypertension (per SD, RR= 0.85 [0.73-0.99]), whereas the PUFA module was not associated with either outcome. Conclusions: Metabolomic signatures positively relating to three common healthful dietary patterns are found to be associated with lower incident cardiometabolic diseases, providing some mechanistic insights into the cardioprotection of high-quality diets.
Perinatal factors during delivery might modulate fetal immunological development and thereby be associated with the development of allergic diseases and asthma later.Perinatal data was recorded during pregnancy and at the time of delivery in regard to 5823 children who were born in Northern Finland in 1985-1986. Data from self-administered questionnaires were available at the ages of 7 and 15-16 years and skin prick tests for four main allergens were carried out at the age of 15-16 years. Only singletons delivered by the vaginal route were analyzed.There was a higher prevalence of doctor-diagnosed asthma at any time of life among children who were delivered by vacuum extraction (RR 1.80, 95% CI 1.27-2.56; P < 0.001) in comparison with spontaneously delivered children. In particular, this risk was increased as regards late-onset asthma (RR 2.41, 95% CI 1.52-3.81; P < 0.001). Perinatal effects had less impact on the development of other asthma, atopy or hay fever.The delivery by vacuum extraction had significant impact on the development of late-onset asthma compared with spontaneously delivered children.
Biological systems have evolved biochemical, electrical, mechanical, and genetic networks to perform essential functions across various length and time scales. High-aspect-ratio biological nanowires, such as bacterial pili and neurites, mediate many of the interactions and homeostasis in and between these networks. Synthetic materials designed to mimic the structure of biological nanowires could also incorporate similar functional properties, and exploiting this structure–function relationship has already proved fruitful in designing biointerfaces. Semiconductor nanowires are a particularly promising class of synthetic nanowires for biointerfaces, given (1) their unique optical and electronic properties and (2) their high degree of synthetic control and versatility. These characteristics enable fabrication of a variety of electronic and photonic nanowire devices, allowing for the formation of well-defined, functional bioelectric interfaces at the biomolecular level to the whole-organ level. In this Focus Review, we first discuss the history of bioelectric interfaces with semiconductor nanowires. We next highlight several important, endogenous biological nanowires and use these as a framework to categorize semiconductor nanowire-based biointerfaces. Within this framework we then review the fundamentals of bioelectric interfaces with semiconductor nanowires and comment on both material choice and device design to form biointerfaces spanning multiple length scales. We conclude with a discussion of areas with the potential for greatest impact using semiconductor nanowire-enabled biointerfaces in the future.
The micromechanical fracture analysis of fiber-reinforced ceramics usually requires explicit consideration of sliding at the fiber-matrix interface that is resisted by frictional shear stress. But an interfacial debonding resistance may have to be overcome before frictional sliding can occur. This paper presents an approximate calculation of the stresses needed to initiate and propagate fiber-matrix debonding in the vicinity of a matrix crack. The results are used to define the parameters of a crack-bridging model that serves to determine the effects of debonding and initial stress on the matrix cracking stress of an aligned fiber composite, as well as their effects on overall composite toughness.
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Elastic fracture mechanics concepts are reexamined for a crack on the interface between dissimilar solids. A derivation by function theory is given of the form of stress and displacement fields in the vicinity of the crack tip, equivalent to complete Williams expansions of both inner and outer (external to a nonlinear or contact zone) type. The complex stress intensity factor K associated with an elastic interface crack, for which contact is ignored, is discussed and, specifically, its validity as a crack tip characterizing parameter is noted for cases of small scale nonlinear material behavior and/or small scale contact zones at the crack tip. That is, similar values of K for two cracked bodies then imply similar states as the crack tip, so that conditions for crack growth can be phrased in terms of K reaching a critical failure locus in a complex plane. The maintenance of a similar state at a crack tip under change of crack length is shown to require alteration of both the magnitude and phase angle of a combined tension and shear loading. Some possible definitions of stress intensity factors KI and KII of classical type associated with interface cracks are discussed. Also, the scaling of interface crack tip plastic zone size with load under small scale yielding conditions is found to deviate from classical scaling, in proportion to the square of the applied load level, and dependences of the field on distance from the tip and on load phase angle are found to be linked together.
: This paper presents calculations of the temperature elevations accompanying rapid plastic deformation near a crack tip. Solutions for the stress and strain distribution in non-hardening materials are employed as a basis for the heating rate distribution. Results are approximate in that temperature independent mechanical and thermal properties are assumed and thermal stressing is neglected. Two cases are considered: a stationary crack under increasing load, and a running crack with locally constant speed and plastic zone size. Numerical results are presented as based on properties of 2024 aluminum alloy, 6Al-4V titanium alloy, and mild steel. Temperature rises predicted for test conditions on these metals seldom exceed 100C. This may, nevertheless, be large enough to influence fracture and to account for the observed rise in roughness at very fast rates. Consequences are examined for the assumption that the localized tip temperature elevation alone governs fracture toughness at very fast rates. (Author)
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
