6,647 research outputs found

    Allostatic load and preterm birth

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    Preterm birth is a universal health problem that is one of the largest unmet medical needs contributing to the global burden of disease. Adding to its complexity is that there are no means to predict who is at risk when pregnancy begins or when women will actually deliver. Until these problems are addressed, there will be no interventions to reduce the risk because those who should be treated will not be known. Considerable evidence now exists that chronic life, generational or accumulated stress is a risk factor for preterm delivery in animal models and in women. This wear and tear on the body and mind is called allostatic load. This review explores the evidence that chronic stress contributes to preterm birth and other adverse pregnancy outcomes in animal and human studies. It explores how allostatic load can be used to, firstly, model stress and preterm birth in animal models and, secondly, how it can be used to develop a predictive model to assess relative risk among women in early pregnancy. Once care providers know who is in the highest risk group, interventions can be developed and applied to mitigate their risk

    A squirmer across Reynolds numbers

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    The self-propulsion of a spherical squirmer – a model swimming organism that achieves locomotion via steady tangential movement of its surface – is quantified across the transition from viscously to inertially dominated flow. Specifically, the flow around a squirmer is computed for Reynolds numbers (ReRe) between 0.01 and 1000 by numerical solution of the Navier–Stokes equations. A squirmer with a fixed swimming stroke and fixed swimming direction is considered. We find that fluid inertia leads to profound differences in the locomotion of pusher (propelled from the rear) versus puller (propelled from the front) squirmers. Specifically, pushers have a swimming speed that increases monotonically with ReRe, and efficient convection of vorticity past their surface leads to steady axisymmetric flow that remains stable up to at least Re=1000Re=1000. In contrast, pullers have a swimming speed that is non-monotonic with ReRe. Moreover, they trap vorticity within their wake, which leads to flow instabilities that cause a decrease in the time-averaged swimming speed at large ReRe. The power expenditure and swimming efficiency are also computed. We show that pushers are more efficient at large ReRe, mainly because the flow around them can remain stable to much greater ReRe than is the case for pullers. Interestingly, if unstable axisymmetric flows at large ReRe are considered, pullers are more efficient due to the development of a Hill’s vortex-like wake structure.This work was funded in part by the European Union through a CIG grant to EL. NGC acknowledges partial support from the John and Claire Bertucci Fellowship in Engineering.This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by Cambridge University Press

    Arginase from kiwifruit: properties and seasonal variation

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    The in vitro activity of arginase (EC 3.5.3.1) was investigated in youngest-mature leaves and roots (1-3 mm diameter) of kiwifruit vines (Actinidia deliciosa var. deliciosa) during an annual growth cycle, and enzyme from root material partially purified. No seasonal trend in the specific activity of arginase was observed in roots. Measurements in leaves, however, rose gradually during early growth and plateaued c. 17 weeks after budbreak. Changes in arginase activity were not correlated with changes in the concentration of arginine (substrate) or glutamine (likely end-product of arginine catabolism) in either tissue during the growth cycle. Purification was by (NH4)2SO4 precipitation and DEAE-cellulose chromatography. The kinetic properties of the enzyme, purified 60-fold over that in crude extracts, indicated a pH optimum of 8.8, and a Km (L-arginine) of 7.85 mM. Partially-purified enzyme was deactivated by dialysis against EDTA, and reactivated in the presence of Mn²⁺, Co²⁺, and Ni²⁺

    The mechanism of catalase loading into porous vaterite CaCO3 crystals by co-synthesis

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    Porous vaterite CaCO3 crystals are nowadays extensively used as high-capacity bio-friendly sacrificial templates for the fabrication of such protein-containing nano- and micro-particles as capsules and beads. The first step in the protein encapsulation is performed through loading of the protein molecules into the crystals. Co-synthesis is one of the most useful and simple methods proven to effectively load crystals with proteins; however, the loading mechanism is still unknown. To understand the mechanism, in this study, we focus on the loading of a model protein catalase into the crystals by means of adsorption into pre-formed crystals (ADS) and co-synthesis (COS). Analysis of the physico-chemical characteristics of the protein in solution and during the loading and simulation of the protein packing into the crystals are performed. COS provides more effective loading than ADS giving protein contents in the crystals of 20.3 and 3.5 w/w%, respectively. Extremely high loading for COS providing a local protein concentration of about 550 mg mL−1 is explained by intermolecular protein interactions, i.e. formation of protein aggregates induced by CaCl2 during the co-synthesis. This is supported by a lower equilibrium constant obtained for COS (5 × 105 M−1) than for ADS (23 × 105 M−1), indicating a higher affinity of single protein molecules rather than aggregates to the crystal surface. Fitting the adsorption isotherms by classical adsorption models has shown that the Langmuir and BET models describe the adsorption phenomenon better than the Freundlich model, proving the aggregation in solution followed by adsorption of the aggregates into the crystals. We believe that this study will be useful for protein encapsulation through CaCO3 crystals using the COS method

    Features of Imaging of Different Types of Hodgkin’s Lymphoma Using Combined Positron Emission and Computed Tomography

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    Background & Aims. At present, PET-CT has an important clinical significance in Hodgkin’s lymphoma (HL) and is used both for initial tumor staging and restaging and for the evaluation of treatment efficacy. Published data indicate the possible lack of radiotracer accumulation in the tumor tissue in HL before primary treatment. A low metabolic activity of the tumor tissue prior to treatment makes it difficult to assess the treatment dynamics during the anti-tumor therapy. The aim of this work is to determine the incidence of the low metabolic activity of tumor tissue in HL. Methods. Findings of 131 18F-fluorodeoxyglucose (FDG) whole body PET-CT scans of patients with histologically verified HL (over the period from 2011 to 2015) were studied retrospectively. Patterns of FDG accumulation in different histological types of HL, as well as the levels of metabolic activity in patients with tumor-related toxicity symptoms (B-symptoms) were studied. Results. The low metabolic activity was detected in 4 % of patients with de novo HL. The highest levels of metabolic activity were detected in nodular sclerosis and the lowest ones in nodular lymphocyte-predominant HL. Higher levels of radiotracer metabolic activity were observed in patients with general symptoms. Conclusion. In general, a high metabolic activity of the neoplasm is typical for HL. Primary staging before the treatment should be performed for a more accurate evaluation of dynamics of HL treatment outcomes, because in a number of cases a baseline low FDG accumulation in the neoplasm may imitate the absence of a viable tumor tissue in the affected lymph nodes at assessment of treatment results

    LEGAL CULTURE FORMATION OF A FUTURE SPECIALIST

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    Purpose: To identify Legal Culture Formation of a Future Specialist. Methodology: This is an analytical-critical research that uses content analysis and interviews to gain data. In this re-search, all the information obtained are coded, then meaningful propositions were specified and finally a list of these factors are provided. Main Findings: Results showed that knowledge about the foundations of law in the modern times becomes the primary necessity of every member in the society, including students of professional educational institutions, as the success of people in any sphere of their activity largely depends on this: in business, when working in enterprises for hiring new talents or in budgetary organizations, medical care, etc. Applications: The research implications can be used by legal training professional educational institutions and universities. Novelty/Originality: For the first time, hours devoted to the study of law subjects; unsatisfactory qualification of teachers in the legal course; lack of systematic educational and methodical literature, and documentation has been studied

    Nonlocal observables and lightcone-averaging in relativistic thermodynamics

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    The unification of relativity and thermodynamics has been a subject of considerable debate over the last 100 years. The reasons for this are twofold: (i) Thermodynamic variables are nonlocal quantities and, thus, single out a preferred class of hyperplanes in spacetime. (ii) There exist different, seemingly equally plausible ways of defining heat and work in relativistic systems. These ambiguities led, for example, to various proposals for the Lorentz transformation law of temperature. Traditional 'isochronous' formulations of relativistic thermodynamics are neither theoretically satisfactory nor experimentally feasible. Here, we demonstrate how these deficiencies can be resolved by defining thermodynamic quantities with respect to the backward-lightcone of an observation event. This approach yields novel, testable predictions and allows for a straightforward-extension of thermodynamics to General Relativity. Our theoretical considerations are illustrated through three-dimensional relativistic many-body simulations.Comment: typos in Eqs. (12) and (14) corrected, minor additions in the tex

    Relation of C-reactive protein to body fat distribution and features of the metabolic syndrome in Europeans and South Asians.

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    OBJECTIVE: To investigate the association between circulating C-reactive protein (CRP) concentrations and indices of body fat distribution and the insulin resistance syndrome in South Asians and Europeans. DESIGN: : Cross-sectional study. SUBJECTS: A total of 113 healthy South Asian and European men and women in West London (age 40-55 y, body mass index (BMI) 17-34 kg/m(2)). MEASUREMENTS: Fatness and fat distribution parameters (by anthropometry, dual-energy X-ray absorptiometry and abdominal CT scan); oral glucose tolerance test with insulin response; modified fat tolerance test; and CRP concentration by sensitive ELISA. RESULTS: Median CRP level in South Asian women was nearly double that in European women (1.35 vs 0.70 mg/1, P=0.05). Measures of obesity and CRP concentration were significantly associated in both ethnic groups. The correlation to CRP was especially strong among South Asians (P0.15). CONCLUSION: We suggest that adiposity and in particular visceral adipose tissue is a key promoter of low-grade chronic inflammation. This observation may in part account for the association of CRP with markers of the metabolic syndrome. Future studies should confirm whether CRP concentrations are elevated in South Asians and whether losing weight by exercise or diet, or reduction in visceral fat mass, is associated with reduction in plasma CRP concentrations
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