2,243 research outputs found
Quantifying the Differences in Binding Affinity of Reduced Glutathione for Glutathione S-Transferase at pH 6.5 and 8.5 Using Isothermal Titration Calorimetry
The binding affinity between an enzyme and its substrate is often dependent on the pH of the local environment. Knowing the pH at which reduced glutathione (GSH) binds with the highest affinity to the enzyme glutathione S-transferase (GST) is useful for determining the optimal pH for purification of GST-fusion proteins during GST-affinity chromatography. In this study, GST of the species Schistosoma japonicum was purified, quantified, and utilized to study its binding interaction with GSH at pH 6.5 and 8.5 via isothermal titration calorimetry (ITC). After protein expression, extraction, and purification, the GST concentration was quantified using QubitTM fluorometry. Thermodynamic properties and a dissociation constant (KD) for each experiment were obtained utilizing the MicroCal PEAQ-ITC Analysis Software for the binding of GSH to GST at pH 6.5 and 8.5. Statistical analysis of the technical replicate data was performed to obtain an average and standard deviation of the KD at each pH point. The results indicate a statistically significant difference (
Effect of high oxygen pressure annealing on superconducting Nd1.85Ce0.15CuO4 thin films by pulsed laser deposition from Cu-enriched targets
We show that the quality of Nd1.85Ce0.15CuO4 films grown by pulsed laser
deposition can be enhanced by using a non-stoichiometric target with extra
copper added to suppress the formation of a parasitic (Nd, Ce)2O3 phase. The
properties of these films are less dependent on the exact annealing procedure
after deposition as compared to films grown from a stoichiometric target. Film
growth can be followed by a 1 bar oxygen annealing, after an initial vacuum
annealing, while retaining the superconducting properties and quality. This
enables the integration of electron-doped cuprates with their hole-doped
counterparts on a single chip, to create, for example, superconducting
pn-junctions.Comment: This is an author-created, un-copyedited version of an article
accepted for publication in Superconductor Science and Technology. The
publisher is not responsible for any errors or omissions in this version of
the manuscript or any version derived from it. The Version of Record is
available online at http://dx.doi.org/10.1088/0953-2048/27/4/04401
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A parameterized approach to modeling and forecasting mortality
A new method is proposed of constructing mortality forecasts. This parameterized approach utilizes Generalized Linear Models (GLMs), based on heteroscedastic Poisson (non-additive) error structures, and using an orthonormal polynomial design matrix. Principal Component (PC) analysis is then applied to the cross-sectional fitted parameters. The produced model can be viewed either as a one-factor parameterized model where the time series are the fitted parameters, or as a principal component model, namely a log-bilinear hierarchical statistical association model of Goodman [Goodman, L.A., 1991. Measures, models, and graphical displays in the analysis of cross-classified data. J. Amer. Statist. Assoc. 86(416), 1085–1111] or equivalently as a generalized Lee–Carter model with p interaction terms. Mortality forecasts are obtained by applying dynamic linear regression models to the PCs. Two applications are presented: Sweden (1751–2006) and Greece (1957–2006)
Live imaging of tumor initiation in zebrafish larvae reveals a trophic role for leukocyte-derived PGE(2)
SummaryEpidemiology studies and clinical trials have suggested that the use of non-steroidal anti-inflammatory drugs (NSAIDs), including aspirin, can significantly reduce the incidence of and mortality associated with many cancers [1–3], and upregulation of the COX2-PGE2 pathway in tumor microenvironments might drive several aspects of cancer progression [4–6]. For these reasons, the mechanisms linking COX blockade and cancer prevention have long been an area of active investigation [7]. During carcinogenesis, COX-2 is expressed both by malignant epithelial cells [8, 9] and by tumor-associated stromal cells, including macrophages [10–12], but the observation that NSAIDs are most effective in cancer prevention in APCmin/+ mice if the mice are treated from conception [13] suggests that the COX-2/PGE2 pathway might also be critical at the earliest stages of tumor development. In this study we take advantage of the translucency and genetic tractability of zebrafish larvae to investigate the involvement of inflammatory cells at cancer initiation, when transformed cells first arise in tissues. We previously showed that innate immune cells supply early transformed cells with proliferative cues [14] and, by using complementary pharmacological and genetic experiments, we now show that prostaglandin E2 (PGE2) is the trophic signal required for this expansion of transformed cells. Our in vivo observations at these early stages of cancer initiation provide a potential mechanistic explanation for why long-term use of low doses of NSAIDs, including aspirin, might reduce cancer onset
Nebraska Population Projections: State, County, Region, and Town: 1975-2020
Many types of planning efforts depend on information about the future size and composition of the population. The projections in this report are intended for use in planning. Even under the best of circumstances, however, making projections that accurately indicate future prospects is difficult. Therefore, caution should be exercised when using these or any population projections.
The population projections in this report are the direct product of specific assumptions about future trends infertility, mortality, and migration. These assumptions, in turn, are based on information about past trends in factors which are considered to be the principal determinants of population change. It is the responsibility of the users of this report to evaluate the reasonableness of the assumptions underlying the projections and choose projections appropriate to their needs or employ additional information that may be available to them to arrive at different assumptions
Can the British Heart Foundation PocketCPR Application Improve the Performance of Chest Compressions During Bystander Resuscitation: a Randomised Crossover Manikin Study
This study aims to determine whether the British Heart Foundation (BHF) PocketCPR application can improve the depth and rate of chest compression, and therefore be confidently recommended for bystander use.
118 candidates were recruited into a randomised crossover manikin trial. Each candidate performed CPR for two-minutes without instruction, or performed chest compressions using the PocketCPR application. Candidates then performed a further two minutes of CPR within the opposite arm.
The number of chest compressions performed improved when PocketCPR was used compared to chest compressions when it was not (44.28% v40.57, P<0.001). The number of chest compressions performed to the required depth was higher in the PocketCPR group (90.86 v 66.26).
The BHF PocketCPR application improved the percentage of chest compressions that were performed to the required depth. Despite this, more work is required in order to develop a feedback device that can improve bystander CPR without creating delay
Iron bioavailability of sweet potato and moringa leaves in comparision with leafy green vegetables commonly consumed in Ghana
Introduction: Iron deficiency anaemia (IDA) is a significant public health problem in Northern Ghana especially amongst women and children. Leafy green vegetables are major contributors to iron intake in this part of the world; poor iron bioavailability from these food sources may be part of the reason for the high prevalence of IDA. Evidence suggests that sweet potato and Moringa leaves might be better sources of bioavailable iron, compared with other leafy green vegetables, as both have high levels of iron, and also beta−carotene − a dietary factor that has been suggested to improve iron bioavailability.
Aims/Hypothesis: Our research aims were to evaluate iron bioavailability of sweet potato and Moringa leaves in comparison with other leafy green vegetables commonly consumed in Ghana. We hypothesized that iron uptake from sweet potato and Moringa leaves would be higher compared with the other tested vegetables.
Methods: We used the Caco−2 cell/in vitro digestion system; Caco−2 cell ferritin formation was used as a surrogate marker of iron bioavailability. In addition, we also measured levels of other nutrients and dietary factors known to affect iron bioavailability: beta−carotene, iron, calcium, zinc, ascorbate, phytates and polyphenols.
Results: Iron bioavailability from all tested vegetables was poor despite relatively high absolute levels of iron in the leaf samples (14.5 − 24.6 mg/100 grams dry weight); there was no statistically significant difference in iron uptake between any of the tested varieties or the control sample with no added iron. Levels of phytates and polyphenols, known inhibitors of iron uptake, were high and probably accounted for the low iron bioavailability of tested leaves. As expected, beta−carotene levels were highest in the sweet potato and Moringa leaves (ranging from 47−98 micrograms retinol activity equivalent)/gram freeze dried leaf) − approximately 100% more compared with the other leafy green vegetables, with the exception of the purple leafed sweet potato variety tested that had approximately the same amount of beta−carotene as the commonly consumed vegetables.
Conclusion: In our in vitro model neither sweet potato nor Moringa leaves demonstrated good iron bioavailability suggesting that increased consumption of these vegetables would not lead to improved iron status. However, both leaves were good sources of beta−carotene, and further testing in vivo to evaluate whether they could impact on vitamin A status may be warranted
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Common mortality modeling and coherent forecasts. An empirical analysis of worldwide mortality data
A new common mortality modeling structure is presented for analyzing mortality dynamics for a pool of countries, under the framework of generalized linear models (GLM). The countries are first classified by fuzzy c-means cluster analysis in order to construct the common sparse age-period model structure for the mortality experience. Next, we propose a method to create the common sex difference age-period model structure and then use this to produce the residual age-periodmodel structure for each country and sex. The time related principal components are extrapolated using dynamic linear regression (DLR) models and coherent mortality forecasts are investigated. We make use of mortality data from the “Human Mortality Database”
Proximity-to-goal as a constraint on patterns of behaviour in attacker-defender dyads in team games
Abstract The aim of this study was to determine whether spatiotemporal interactions between footballers and the ball in 1 vs. 1 sub-phases are influenced by their proximity to the goal area. Twelve participants (age 15.3 +/- 0.5 years) performed as attackers and defenders in 1 vs. 1 dyads across three field positions: (a) attacking the goal, (b) in midfield, and (c) advancing away from the goal area. In each position, the dribbler was required to move beyond an immediate defender with the ball towards the opposition goal. Interactions of attacker-defender dyads were filmed with player and ball displacement trajectories digitized using manual tracking software. One-way repeated measures analysis of variance was used to examine differences in mean defender-to-ball distance after this value had stabilized. Maximum attacker-to-ball distance was also compared as a function of proximity-to-goal. Significant differences were observed for defender-to-ball distance between locations (a) and (c) at the moment when the defender-to-ball distance had stabilized (a: 1.69 +/- 0.64 m; c: 1.15 +/- 0.59 m; P < 0.05). Findings indicate that proximity-to-goal influenced the performance of players, particularly when attacking or advancing away from goal areas, providing implications for training design in football. In this study, the task constraints of football revealed subtly different player interactions than observed in previous studies of dyadic systems in basketball and rugby union
The relationship of dielectric response and water activity in food
This study has deduced a correlation between points of inflection of water activity and loss factor with respect to moisture content. A point of inflection in loss factor with respect to moisture content was found to coincide with the sorption isotherm point of inflection that defines the transition from multilayer to solution in every instance analysed, with an average difference of just 0.01kg.kg-1. Food can support microbial growth and chemical reactions in water activity levels above this critical transition. This correlation was discovered using published dielectric and sorption data for specific foods at similar temperatures. It was found that low sugar foods containing high levels of hydrocolloids generally exhibited different behaviour from fruits. This shows that microwave heating behaviour will be different in fruits compared to low sugar foods with high hydrocolloid content when drying to achieve a certain water activity and therefore shelf life
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