1,829 research outputs found
Revisiting the Thermodynamic Stability of Indomethacin Polymorphs with Low-Frequency Vibrational Spectroscopy and Quantum Mechanical Simulations
The two major polymorphs of the active pharmaceutical ingredient indomethacin were studied using a combination of experimental low-frequency vibrational spectroscopies, theoretical solid-state density functional theory and ab initio molecular dynamics calculations. The results enable a complete spectral assignment of the low-frequency IR and Raman spectra, and yield new insight into the energetic and dynamical factors present within the solids to be understood. Ultimately, these results are used to rationalize the thermodynamic properties of the two crystals, which result in a contradiction to the long-held belief that the γ-form is the more stable polymorph at ambient conditions due to its predominant abundance. Overall, the study highlights the combined role that molecular conformation, bulk packing arrangement, and intermolecular forces have on the ultimate properties of pharmaceutical crystals, and the need for detailed analyses into all of these effects in order to predict the properties of materials
Life-course origins of social inequalities in adult immune cell markers of inflammation in a developing southern Chinese population: the Guangzhou Biobank Cohort Study
BACKGROUND: Socioeconomic position (SEP) throughout life is associated with cardiovascular disease, though the mechanisms linking these two are unclear. It is also unclear whether there are critical periods in the life course when exposure to better socioeconomic conditions confers advantages or whether SEP exposures accumulate across the whole life course. Inflammation may be a mechanism linking socioeconomic position (SEP) with cardiovascular disease. In a large sample of older residents of Guangzhou, in southern China, we examined the association of life course SEP with inflammation. METHODS: In baseline data on 9,981 adults (>/= 50 years old) from the Guangzhou Biobank Cohort Study (2006-08), we used multivariable linear regression and model fit to assess the associations of life course SEP at four stages (childhood, early adult, late adult and current) with white blood, granulocyte and lymphocyte cell counts. RESULTS: A model including SEP at all four life stages best explained the association of life course SEP with white blood and granulocyte cell count for men and women, with early adult SEP (education) making the largest contribution. A critical period model best explained the association of life course SEP with lymphocyte count, with sex-specific associations. Early adult SEP was negatively associated with lymphocytes for women. CONCLUSIONS: Low SEP throughout life may negatively impact late adult immune-inflammatory status. However, some aspects of immune-inflammatory status may be sensitive to earlier exposures, with sex-specific associations. The findings were compatible with the hypothesis that in a developing population, upregulation of the gonadotropic axis with economic development may obscure the normally protective effects of social advantage for men.published_or_final_versio
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Converting Boundary Representation Solid Models to Half-Space Representation Models for Monte Carlo Analysis
Solid modeling computer software systems provide for the design of three-dimensional solid models used in the design and analysis of physical components. The current state-of-the-art in solid modeling representation uses a boundary representation format in which geometry and topology are used to form three-dimensional boundaries of the solid. The geometry representation used in these systems is cubic B-spline curves and surfaces--a network of cubic B-spline functions in three-dimensional Cartesian coordinate space. Many Monte Carlo codes, however, use a geometry representation in which geometry units are specified by intersections and unions of half-spaces. This paper describes an algorithm for converting from a boundary representation to a half-space representation
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A keff Search Capability in MC21
The MC21 Monte Carlo code is required to permit an individual geometric component or groups of components to be tagged as ''movable'' within some permissible range. Typical examples of such movable components would be control devices such as translating rods or rotating drums. Given this geometric information, a target multiplication factor (k{sub eff}), and a convergence criterion, MC21 will iterate on movable component positions and return a final position that reflects a k{sub eff} close to the target value. An initial version of this capability is demonstrated through modifications to MC21 that sets the geometry data structures for the movable components, calls the main Fortran-95 solver to compute k{sub eff}, and converges on the final position. This approach uses an adaptive batching algorithm that continually increases the accuracy of each successive MC21 k{sub eff} result as the movable geometry approaches the converged position
Associação dos Antigos Alunos da Universidade da Madeira (AAAUMA)
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Unintended Consequences of Incentive Provision for Behaviour Change and Maintenance around Childbirth
Financial (positive or negative) and non-financial incentives or rewards are increasingly used in attempts to influence health behaviours. While unintended consequences of incentive provision are discussed in the literature, evidence syntheses did not identify any primary research with the aim of investigating unintended consequences of incentive interventions for lifestyle behaviour change. Our objective was to investigate perceived positive and negative unintended consequences of incentive provision for a shortlist of seven promising incentive strategies for smoking cessation in pregnancy and breastfeeding. A multi-disciplinary, mixed-methods approach included involving two service-user mother and baby groups from disadvantaged areas with experience of the target behaviours as study co-investigators. Systematic reviews informed the shortlist of incentive strategies. Qualitative semi-structured interviews and a web-based survey of health professionals asked open questions on positive and negative consequences of incentives. The participants from three UK regions were a diverse sample with and without direct experience of incentive interventions: 88 pregnant women/recent mothers/partners/family members; 53 service providers; 24 experts/decision makers and interactive discussions with 63 conference attendees. Maternity and early years health professionals (n = 497) including doctors, midwives, health visitors, public health and related staff participated in the survey. Qualitative analysis identified ethical, political, cultural, social and psychological implications of incentive delivery at population and individual levels. Four key themes emerged: how incentives can address or create inequalities; enhance or diminish intrinsic motivation and wellbeing; have a positive or negative effect on relationships with others within personal networks or health providers; and can impact on health systems and resources by raising awareness and directing service delivery, but may be detrimental to other health care areas. Financial incentives are controversial and generated emotive and oppositional responses. The planning, design and delivery of future incentive interventions should evaluate unexpected consequences to inform the evidence for effectiveness, cost-effectiveness and future implementation
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The MC21 Monte Carlo Transport Code
MC21 is a new Monte Carlo neutron and photon transport code currently under joint development at the Knolls Atomic Power Laboratory and the Bettis Atomic Power Laboratory. MC21 is the Monte Carlo transport kernel of the broader Common Monte Carlo Design Tool (CMCDT), which is also currently under development. The vision for CMCDT is to provide an automated, computer-aided modeling and post-processing environment integrated with a Monte Carlo solver that is optimized for reactor analysis. CMCDT represents a strategy to push the Monte Carlo method beyond its traditional role as a benchmarking tool or ''tool of last resort'' and into a dominant design role. This paper describes various aspects of the code, including the neutron physics and nuclear data treatments, the geometry representation, and the tally and depletion capabilities
Silver hake tracks changes in Northwest Atlantic circulation
Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature Communications 2 (2011): 412, doi:10.1038/ncomms1420.Recent studies documenting shifts in spatial distribution of many organisms in response
to a warming climate highlight the need to understand the mechanisms underlying species
distribution at large spatial scales. Here we present one noteworthy example of remote
oceanographic processes governing the spatial distribution of adult silver hake, Merluccius
bilinearis, a commercially important fish in the Northeast US shelf region. Changes in spatial
distribution of silver hake over the last 40 years are highly correlated with the position of the
Gulf Stream (GS). These changes in distribution are in direct response to local changes in
bottom temperature on the continental shelf that are responding to the same large scale
circulation change affecting the GS path, namely changes in the Atlantic Meridional Overturning
Circulation (AMOC). If AMOC weakens as is suggested by global climate models, silver hake
distribution will remain in a poleward position, the extent to which could be forecast at both
decadal and multidecadal scales.J.A.N. was supported by the NOAA
Fisheries and the Environment program (FATE). T.M.J. and Y.O.K. were supported by the
WHOI Ocean Climate Change Institute and Ocean Life Institute
Functional intercomparison of intraoperative radiotherapy equipment – Photon Radiosurgery System
BACKGROUND: Intraoperative Radiotherapy (IORT) is a method by which a critical radiation dose is delivered to the tumour bed immediately after surgical excision. It is being investigated whether a single high dose of radiation will impart the same clinical benefit as a standard course of external beam therapy. Our centre has four Photon Radiosurgery Systems (PRS) currently used to irradiate breast and neurological sites. MATERIALS AND METHODS: The PRS comprises an x-ray generator, control console, quality assurance tools and a mobile gantry. We investigated the dosimetric characteristics of each source and its performance stability over a period of time. We investigated half value layer, output diminution factor, internal radiation monitor (IRM) reproducibility and depth-doses in water. The half value layer was determined in air by the broad beam method, using high purity aluminium attenuators. To quantify beam hardening at clinical depths, solid water attenuators of 5 and 10 mm were placed between the x-ray probe and attenuators. The ion chamber current was monitored over 30 minutes to deduce an output diminution factor. IRM reproducibility was investigated under various exposures. Depth-dose curves in water were obtained at distances up to 35 mm from the probe. RESULTS: The mean energies for the beam attenuated by 5 and 10 mm of solid water were derived from ICRU Report 17 and found to be 18 and 24 keV. The average output level over a period of 30 minutes was found to be 99.12%. The average difference between the preset IRM limit and the total IRM count was less than 0.5%. For three x-ray sources, the average difference between the calculated and actual treatment times was found to be 0.62% (n = 30). The beam attenuation in water varied by approximately 1/r(3). CONCLUSION: The x-ray sources are stable over time. Most measurements were found to lie within the manufacturer's tolerances and an intercomparison of these checks suggests that the four x-ray sources have similar performance characteristics
Enhanced warming over the global subtropical western boundary currents
Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature Climate Change 2 (2012): 161-166, doi:10.1038/nclimate1353.Subtropical western boundary currents are warm, fast flowing currents that
form on the western side of ocean basins. They carry warm tropical water to the
mid-latitudes and vent large amounts of heat and moisture to the atmosphere
along their paths, affecting atmospheric jet streams and mid-latitude storms, as
well as ocean carbon uptake. The possibility that these highly energetic and
nonlinear currents might change under greenhouse gas forcing has raised
significant concerns, but detecting such changes is challenging owing to limited
observations. Here, using reconstructed sea surface temperature datasets and
newly developed century-long ocean and atmosphere reanalysis products, we
find that the post-1900 surface ocean warming rate over the path of these
currents is two to three times faster than the global mean surface ocean warming
rate. The accelerated warming is associated with a synchronous poleward shift
and/or intensification of global subtropical western boundary currents in
conjunction with a systematic change in winds over both hemispheres. This enhanced warming may reduce ocean's ability to absorb anthropogenic carbon
dioxide over these regions. However, uncertainties in detection and attribution of
these warming trends remain, pointing to a need for a long-term monitoring
network of the global western boundary currents and their extensions.This work is supported by China National Key Basic Research Project
(2007CB411800) and National Natural Science Foundation Projects (40788002,
40921004). WC is supported by the Australian Climate Change Science program and
the Southeast Australia Climate Initiative. HN is supported in part by the Japanese
Ministry of Education, Culture, Sports, Science and Technology through Grant-in-Aid
for Scientific Research on Innovative Areas #2205 and by the Japanese Ministry of
Environment through Global Environment Research Fund (S-5). MJM is supported by
NOAA’s Climate Program Office.2012-07-2
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