1,576 research outputs found
A parallel multistate framework for atomistic non-equilibrium reaction dynamics of solutes in strongly interacting organic solvents
We describe a parallel linear-scaling computational framework developed to
implement arbitrarily large multi-state empirical valence bond (MS-EVB)
calculations within CHARMM. Forces are obtained using the Hellman-Feynmann
relationship, giving continuous gradients, and excellent energy conservation.
Utilizing multi-dimensional Gaussian coupling elements fit to CCSD(T)-F12
electronic structure theory, we built a 64-state MS-EVB model designed to study
the F + CD3CN -> DF + CD2CN reaction in CD3CN solvent. This approach allows us
to build a reactive potential energy surface (PES) whose balanced accuracy and
efficiency considerably surpass what we could achieve otherwise. We use our PES
to run MD simulations, and examine a range of transient observables which
follow in the wake of reaction, including transient spectra of the DF
vibrational band, time dependent profiles of vibrationally excited DF in CD3CN
solvent, and relaxation rates for energy flow from DF into the solvent, all of
which agree well with experimental observations. Immediately following
deuterium abstraction, the nascent DF is in a non-equilibrium regime in two
different respects: (1) it is highly excited, with ~23 kcal mol-1 localized in
the stretch; and (2) not yet Hydrogen bonded to the CD3CN solvent, its
microsolvation environment is intermediate between the non-interacting
gas-phase limit and the solution-phase equilibrium limit. Vibrational
relaxation of the nascent DF results in a spectral blue shift, while relaxation
of its microsolvation environment results in a red shift. These two competing
effects result in a post-reaction relaxation profile distinct from that
observed when DF vibration excitation occurs within an equilibrium
microsolvation environment. The parallel software framework presented in this
paper should be more broadly applicable to a range of complex reactive systems.Comment: 58 pages and 29 Figure
Life-Time Covariation of Major Cardiovascular Diseases: A 40-Year Longitudinal Study and Genetic Studies
BACKGROUND: It is known that certain cardiovascular diseases (CVD) are associated, like atrial fibrillation and stroke. However, for other CVDs, the links and temporal trends are less studied. In this longitudinal study, we have investigated temporal epidemiological and genetic associations between different CVDs. METHODS: The ULSAM (Uppsala Longitudinal Study of Adult Men; 2322 men aged 50 years) has been followed for 40 years regarding 4 major CVDs (incident myocardial infarction, ischemic stroke, heart failure, and atrial fibrillation). For the genetic analyses, publicly available data were used. RESULTS: Using multistate modeling, significant relationships were seen between pairs of all of the 4 investigated CVDs. However, the risk of obtaining one additional CVD differed substantially both between different CVDs and between their temporal order. The relationship between heart failure and atrial fibrillation showed a high risk ratio (risk ratios, 24-26) regardless of the temporal order. A consistent association was seen also for myocardial infarction and atrial fibrillation but with a lower relative risk (risk ratios, 4-5). In contrast, the risk of receiving a diagnosis of heart failure following a myocardial infarction was almost twice as high as for the reverse temporal order (risk ratios, 16 versus 9). Genetic loci linked to traditional risk factors could partly explain the observed associations between the CVDs, but pathway analyses disclosed also other pathophysiological links. CONCLUSIONS: During 40 years, all of the 4 investigated CVDs were pairwise associated with each other regardless of the temporal order of occurrence, but the risk magnitude differed between different CVDs and their temporal order. Genetic analyses disclosed new pathophysiological links between CVDs
Risk map as a library management information dashboard: a case study in adapting a configural display
In this paper, we report on our application of Cognitive Work Analysis to create an Abstraction Hierarchy model that helps librarians identify key functional relationships for managing the overall performance of a library. By themselves, functional relationships are not as useful in providing insights into the reasons for good or poor performance. However, when these functional relationships are set against the context of system invariants and constraints, they can provide library managers information useful for diagnosis and localization of problems. We propose the Risk Map visualization technique as an information dashboard to cognitively access these functional relationships. Furthermore, when these functional relationships are portrayed over time, trends and patterns can be detected with relative ease
Left ventricular geometric patterns and adaptations to hemodynamics are similar in elderly men and women
<p>Abstract</p> <p>Background</p> <p>Common conditions such as obesity and hypertension result in hemodynamic alterations that will induce remodeling of the left ventricle (LV). However, differences between the genders in the relationship of hemodynamics to LV geometry are not well known.</p> <p>The present study aims to investigate differences between the genders in this respect, in a sample of elderly persons.</p> <p>Methods</p> <p>Echocardiography and Doppler was performed in a population-based sample aged 70 - The Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study (n = 922).</p> <p>Hemodynamic patterns obtained by echocardiography and Doppler were evaluated in relation to four LV geometric groups (normal, concentric remodeling, eccentric hypertrophy and concentric hypertrophy).</p> <p>Results</p> <p>No significant difference between the genders was observed regarding the prevalence of the LV geometric groups.</p> <p>Mean values of most evaluated echocardiography and Doppler variables differed between men and women, such as LA, IVS, LVEDD and IVRT, but the relationship of hemodynamic variables to LV geometric groups did not differ between the genders.</p> <p>Conclusions</p> <p>Although mean values of many echocardiographic variables differed between men and women, the LV geometric adaptations to a given hemodynamic load appear similar in both genders.</p
Sodium content in processed food items in Sweden compared to other countries: a cross-sectional multinational study
Background: Dietary sodium has a dose-response relationship with cardiovascular disease, and sodium intake in Sweden exceeds national and international recommendations. Two thirds of dietary sodium intake comes from processed foods, and adults in Sweden eat more processed foods than any other European country. We hypothesized that sodium content in processed foods is higher in Sweden than in other countries. The aim of this study was to investigate sodium content in processed food items in Sweden, and how it differs from Australia, France, Hong Kong, South Africa, the United Kingdom and the United States. Methods: Data were collected from retailers by trained research staff using standardized methods. Data were categorized into 10 food categories and compared using Kruskal-Wallis test of ranks. Sodium content in the food items was compared in mg sodium per 100 g of product, based on the nutritional content labels on the packages. Results: Compared to other countries, Sweden had among the highest sodium content in the âdairyâ and âconvenience foodsâ categories, but among the lowest in âcereal and grain products,â âseafood and seafood productsâ and âsnack foodsâ categories. Australia had the overall lowest sodium content, and the US the overall highest. The highest sodium content in most analyzed countries was found in the âmeat and meat productsâ category. The highest median sodium content in any category was found among âsauces, dips, spreads and dressingsâ in Hong Kong. Conclusion: The sodium content differed substantially between countries in all food categories, although contrary to our hypothesis, processed foods overall had lower sodium content in Sweden than in most other included countries. Sodium content in processed food was nonetheless high also in Sweden, and especially so in increasingly consumed food categories, such as âconvenience foodsâ
A comparison of the nutritional qualities of supermarket's own and regular brands of bread in Sweden
Processed food is associated with unhealthy qualities such as higher content of harmful fats, sugars and salt. The aim of our study was to compare the nutritional qualities of supermarket's own brands and regular brands of bread sold in Sweden. Additionally, we compared the nutritional qualities of gluten-free and gluten-containing bread. We collected information from the labels of 332 bread products available in the largest grocery store chains. The Australian Health Star Rating (HSR) system was used to quantify the nutritional quality of each bread product. We compared all supermarket's own brand products to regular brand products, and gluten-free to gluten-containing bread. The mean HSR for the supermarket's own brands was lower than the regular brands (3.6 vs. 3.7; p = 0.046). For the regular brand products, the fibre, sugar and total fat content were greater (p < 0.001, p = 0.002 and p = 0.021, respectively), while less protein (p = 0.009) compared to regular bread products. Gluten-free bread had a lower HSR than gluten-containing bread (mean 3.5 vs. 3.8, respectively; p < 0.001). The regular brand products were slightly healthier than the supermarket's own brands, primarily as a result of a higher fibre content. Gluten-free bread products were slightly unhealthier due to a lower protein content
Tri-critical point and suppression of the Shastry-Sutherland phase in CePdSn by Ni doping
Structural, magnetization and heat capacity measurements were performed on
Ce(PdNi)Sn () alloys, covering the full
range of the MoFeB structure stability. In this system, the two
transitions observed in CePdSn (at \,K and \,K
respectively) converge into a tri-critical point at \,K for
, where the intermediate antiferromagnetic AF phase is
suppressed. The phase boundary decrease is due to an incipient Kondo
screening of the Ce-4f moments and local atomic disorder in the alloy. Both
mechanisms affect the formation of Ce-magnetic dimers on which the
Shastry-Sutherland lattice (SSL) builds up. On the contrary, the
transition to the ferromagnetic ground state increases as a consequence of the
weakening of the AF-SSL phase. Applied magnetic field also suppresses the AF
phase like in the stoichiometric compound.Comment: 6 pages, 8 figure
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