1,576 research outputs found

    Exposure to secondhand smoke and cognitive impairment in non-smokers: national cross sectional study with cotinine measurement.

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    addresses: Department of Public Health and Primary Care, University of Cambridge, Cambridge CB2 2SR. [email protected]: PMCID: PMC2643443types: Journal Article; Multicenter Study; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov'tCopyright © 2009 by the BMJ Publishing Group Ltd. This articles was first published in: BMJ, 2009, Vol. 338, pp. b462 -To examine the association between a biomarker of exposure to secondhand smoke (salivary cotinine concentration) and cognitive impairment

    Serum leptin and risk of cognitive decline in elderly italians.

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    Background: US studies suggest that leptin, a fat-derived hormone, may be protective against the development of dementia. Objective: To investigate the complex relationship between leptin levels and cognitive decline in elderly Italians. Methods: We studied circulating fasting leptin levels in 809 elderly adults free from dementia who participated in the prospective Italian population-based InCHIANTI study between 1998 and 2009 (mean follow-up of 8.0 years). Global cognitive decline was defined as a reduction of ≥5 points on the Mini-Mental State Examination (MMSE). Trail-Making Tests A and B were also incorporated, with cognitive decline defined as discontinued testing or the worst 10% of change from baseline. We also investigated whether any association could be explained by midlife weight and whether cognitive decline was associated with changing leptin levels. Results: The multivariate adjusted relative risk ([RR]; 95% confidence interval [CI]) of cognitive decline on the MMSE was 0.84 (95% CI 0.73–0.97) in relation to baseline sex-standardized log-leptin levels. High leptin levels showed a non-significant trend toward a reduced risk of decline on the Trail-Making Tests A (RR = 0.85, 95% CI 0.71–1.02) and B (RR = 0.90, 0.79–1.02). Adjusting for midlife weight or change in weight did not alter the pattern of results, and cognitive decline was not associated with changing leptin levels. Conclusions: High leptin levels were independently associated with a reduced risk of cognitive decline in elderly Italians.Italian Ministry of HealthU.S. National Institute on AgingAlzheimer’s AssociationNational Institute for Health Research (NIHR)National Institute of Health (Baltimore)National Institute of Health (Maryland)Mary Kinross Charitable TrustJames Tudor FoundationHalpin TrustSir Halley Stewart TrustAge Related Diseases and Health TrustNorman Family Charitable Trus

    Vitamin D and Risk of Neuroimaging Abnormalities.

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    Vitamin D deficiency has been linked with an increased risk of incident all-cause dementia and Alzheimer's disease. The aim of the current study was to explore the potential mechanisms underlying these associations by determining whether low vitamin D concentrations are associated with the development of incident cerebrovascular and neurodegenerative neuroimaging abnormalities. The population consisted of 1,658 participants aged ≥65 years from the US-based Cardiovascular Health Study who were free from prevalent cardiovascular disease, stroke and dementia at baseline in 1992-93. Serum 25-hydroxyvitamin D (25(OH)D) concentrations were determined by liquid chromatography-tandem mass spectrometry from blood samples collected at baseline. The first MRI scan was conducted between 1991-1994 and the second MRI scan was conducted between 1997-1999. Change in white matter grade, ventricular grade and presence of infarcts between MRI scan one and two were used to define neuroimaging abnormalities. During a mean follow-up of 5.0 years, serum 25(OH)D status was not significantly associated with the development of any neuroimaging abnormalities. Using logistic regression models, the multivariate adjusted odds ratios (95% confidence interval) for worsening white matter grade in participants who were severely 25(OH)D deficient (<25 nmol/L) and deficient (≥25-50 nmol/L) were 0.76 (0.35-1.66) and 1.09 (0.76-1.55) compared to participants with sufficient concentrations (≥50 nmol/L). The multivariate adjusted odds ratios for ventricular grade in participants who were severely 25(OH)D deficient and deficient were 0.49 (0.20-1.19) and 1.12 (0.79-1.59) compared to those sufficient. The multivariate adjusted odds ratios for incident infarcts in participants who were severely 25(OH)D deficient and deficient were 1.95 (0.84-4.54) and 0.73 (0.47-1.95) compared to those sufficient. Overall, serum vitamin D concentrations could not be shown to be associated with the development of cerebrovascular or neurodegenerative neuroimaging abnormalities in Cardiovascular Health Study participants.The Cardiovascular Health Study was supported by contracts HHSN268201200036C, HHSN268200800007C, N01 HC55222, N01HC85079, N01HC85080, N01HC85081, N01HC85082, N01HC85083, N01HC85086, and grant HL080295 from the National Heart, Lung, and Blood Institute (NHLBI), with additional contribution from the National Institute of Neurological Disorders and Stroke (NINDS). Additional support was provided by AG023629, AG20098, AG15928 and HL084443 from the National Institute on Aging (NIA). A full list of principal CHS investigators and institutions can be found at chs-nhlbi.org. Additional support was also provided by NIRG-11-200737 from the Alzheimer’s Association, the Mary Kinross Charitable Trust, the James Tudor Foundation, the Halpin Trust, the Age Related Diseases and Health Trust, and the Norman Family Charitable Trust (to D.J.L.). This research was supported by the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care South West Peninsula at the Royal Devon and Exeter NHS Foundation Trust. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. The National Institutes of Health was involved in the original design and conduct of the Cardiovascular Health Study and in the data collection methods

    Vitamin D and the risk of dementia and Alzheimer disease

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    OBJECTIVE: To determine whether low vitamin D concentrations are associated with an increased risk of incident all-cause dementia and Alzheimer disease. METHODS: One thousand six hundred fifty-eight elderly ambulatory adults free from dementia, cardiovascular disease, and stroke who participated in the US population-based Cardiovascular Health Study between 1992-1993 and 1999 were included. Serum 25-hydroxyvitamin D (25(OH)D) concentrations were determined by liquid chromatography-tandem mass spectrometry from blood samples collected in 1992-1993. Incident all-cause dementia and Alzheimer disease status were assessed during follow-up using National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association criteria. RESULTS: During a mean follow-up of 5.6 years, 171 participants developed all-cause dementia, including 102 cases of Alzheimer disease. Using Cox proportional hazards models, the multivariate adjusted hazard ratios (95% confidence interval [CI]) for incident all-cause dementia in participants who were severely 25(OH)D deficient (<25 nmol/L) and deficient (≥25 to <50 nmol/L) were 2.25 (95% CI: 1.23-4.13) and 1.53 (95% CI: 1.06-2.21) compared to participants with sufficient concentrations (≥50 nmol/L). The multivariate adjusted hazard ratios for incident Alzheimer disease in participants who were severely 25(OH)D deficient and deficient compared to participants with sufficient concentrations were 2.22 (95% CI: 1.02-4.83) and 1.69 (95% CI: 1.06-2.69). In multivariate adjusted penalized smoothing spline plots, the risk of all-cause dementia and Alzheimer disease markedly increased below a threshold of 50 nmol/L. CONCLUSION: Our results confirm that vitamin D deficiency is associated with a substantially increased risk of all-cause dementia and Alzheimer disease. This adds to the ongoing debate about the role of vitamin D in nonskeletal conditions.National Heart, Lung, and Blood InstituteNational Institute of Neurological Disorders and StrokeNational Institute on AgingAlzheimer's AssociationMary Kinross Charitable TrustJames Tudor FoundationHalpin TrustAge Related Diseases and Health TrustNorman Family Charitable TrustUK National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care (CLAHRC) for the South West Peninsul

    Multiferroicity in an organic charge-transfer salt: Electric-dipole-driven magnetism

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    Multiferroics, showing simultaneous ordering of electrical and magnetic degrees of freedom, are remarkable materials as seen from both the academic and technological points of view. A prominent mechanism of multiferroicity is the spin-driven ferroelectricity, often found in frustrated antiferromagnets with helical spin order. There, similar to conventional ferroelectrics, the electrical dipoles arise from an off-centre displacement of ions. However, recently a different mechanism, namely purely electronic ferroelectricity, where charge order breaks inversion symmetry, has attracted considerable interest. Here we provide evidence for this exotic type of ferroelectricity, accompanied by antiferromagnetic spin order, in a two-dimensional organic charge-transfer salt, thus representing a new class of multiferroics. Quite unexpectedly for electronic ferroelectrics, dipolar and spin order arise nearly simultaneously. This can be ascribed to the loss of spin frustration induced by the ferroelectric ordering. Hence, here the spin order is driven by the ferroelectricity, in marked contrast to the spin-driven ferroelectricity in helical magnets.Comment: 8 pages, 9 figures (including 4 pages and 6 figures in supplementary information). Version 2 with minor errors corrected (legend of Fig. 3c and definition of vectors e and Q

    Quantum dynamics in strong fluctuating fields

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    A large number of multifaceted quantum transport processes in molecular systems and physical nanosystems can be treated in terms of quantum relaxation processes which couple to one or several fluctuating environments. A thermal equilibrium environment can conveniently be modelled by a thermal bath of harmonic oscillators. An archetype situation provides a two-state dissipative quantum dynamics, commonly known under the label of a spin-boson dynamics. An interesting and nontrivial physical situation emerges, however, when the quantum dynamics evolves far away from thermal equilibrium. This occurs, for example, when a charge transferring medium possesses nonequilibrium degrees of freedom, or when a strong time-dependent control field is applied externally. Accordingly, certain parameters of underlying quantum subsystem acquire stochastic character. Herein, we review the general theoretical framework which is based on the method of projector operators, yielding the quantum master equations for systems that are exposed to strong external fields. This allows one to investigate on a common basis the influence of nonequilibrium fluctuations and periodic electrical fields on quantum transport processes. Most importantly, such strong fluctuating fields induce a whole variety of nonlinear and nonequilibrium phenomena. A characteristic feature of such dynamics is the absence of thermal (quantum) detailed balance.Comment: review article, Advances in Physics (2005), in pres

    Seed Germination Strategies of Mediterranean Halophytes Under Saline Condition

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    The study of the ecological strategies adopted by seed plants to ensure their success in different environments is closely related to germination ecology. This implies a careful knowledge of ecophysiology of seeds and, therefore, also of interaction between plants and the complexity of external factors. In particular, the environmental conditions of the area where a plant grows and produces seeds represent the main factors that influence successful seedling establishment. The physical-chemical features of habitats, and therefore their heterogeneity, affect the behavior of seeds in different ways. In addition to the timing of seed production, they can induce or terminate dormancy and/or germination and influence the germination pattern of different seeds in the same plant and so the composition and dispersal of soil seed banks. Salinity is a major abiotic stress affecting growth and plant productivity worldwide, constituting one of the main topics of study in the field of plant physiology. Halophytes are the plants that have the availability to survive and develop in different types of saline habitats. In this chapter, we consider some examples to illustrate the main adaptive strategies used by the seeds of halophytes on ecophysiological perspectives to survive in habitats affected by high levels of salinity. The focus is on the species that live in the brackish or salt coastal areas of the Mediterranean Basin. On these environments, the salt stress may act synergistically with intense anthropic pressure, generating profound alterations in the ecosystem and threatening the survival of the plant species very sensitive to the effects of climate change also. The results show the main diverse strategies, such as dormancy cycling, seed heteromorphism, and recovery capacity, from saline shock, favoring the chances of seed survival. The interaction between temperature and salinity during germination was also discussed assessing its crucial role as an ecological strategy

    A realist evaluation of a collaborative model to support research co-production in long-term care settings in England: the ExCHANGE protocol

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    This is the final version. Available from BMC via the DOI in this record. Background: Collaborative working between academic institutions and those who provide health and social care has been identified as integral in order to produce acceptable, relevant, and timely research, and for outputs to be useful and practical to implement. The ExCHANGE Collaboration aims to bring together researchers and people working, living in and visiting care homes to build capacity, share and mobilise knowledge, and identify key areas for future research. This paper describes an embedded, formative, realist and theory-driven evaluation which aims to gather information about how successful the ExCHANGE Collaboration is perceived to be in achieving its aims. An existing realist programme theory from the literature – Closer Collaboration – will be supplemented by two substantive theories: Co-production and Knowledge Brokering. This will result in an initial programme theory which will be tested by this formative evaluation to refine understanding of how the ExCHANGE Collaboration works. Methods: The evaluation will employ mixed qualitative methods, including: analysis of documents such as feedback forms, Knowledge Broker journal/diary, event attendance records, risk and issues logs and other relevant paperwork gathered as part of project delivery; observations of events/activities; and interviews with care home providers and staff, care home residents, residents’ family members, and researchers who are involved in the project (both project design/delivery, and also attendance or involvement in project activities/events). Framework Analysis will be used to interpret the data collected; analysis will be strategic, by focusing on particular key areas of importance in the developing theory of how the ExCHANGE Collaboration might achieve change. Results: The results of this study are expected to be published in 2022. Discussion: This evaluation will investigate how successful the ExCHANGE Collaboration is perceived to be in achieving its aims, in what way, in which contexts, and how this may differ for those involved. It will do this by testing an initial programme theory about how the collaboration works, for whom, under which circumstances, and in what way. Findings will be shared through written publication, an end of project learning event for those involved/interested in the project, and a lay summary to be made publically available.Alzheimer's SocietyDunhill Medical TrustNational Institute for Health Research Applied Research Collaboration South West Peninsul

    Cognitive health among older adults in the United States and in England

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    <p>Abstract</p> <p>Background</p> <p>Cognitive function is a key determinant of independence and quality of life among older adults. Compared to adults in England, US adults have a greater prevalence of cardiovascular risk factors and disease that may lead to poorer cognitive function. We compared cognitive performance of older adults in the US and England, and sought to identify sociodemographic and medical factors associated with differences in cognitive function between the two countries.</p> <p>Methods</p> <p>Data were from the 2002 waves of the US Health and Retirement Study (HRS) (n = 8,299) and the English Longitudinal Study of Ageing (ELSA) (n = 5,276), nationally representative population-based studies designed to facilitate direct comparisons of health, wealth, and well-being. There were differences in the administration of the HRS and ELSA surveys, including use of both telephone and in-person administration of the HRS compared to only in-person administration of the ELSA, and a significantly higher response rate for the HRS (87% for the HRS vs. 67% for the ELSA). In each country, we assessed cognitive performance in non-hispanic whites aged 65 and over using the same tests of memory and orientation (0 to 24 point scale).</p> <p>Results</p> <p>US adults scored significantly better than English adults on the 24-point cognitive scale (unadjusted mean: 12.8 vs. 11.4, P < .001; age- and sex-adjusted: 13.2 vs. 11.7, P < .001). The US cognitive advantage was apparent even though US adults had a significantly higher prevalence of cardiovascular risk factors and disease. In a series of OLS regression analyses that controlled for a range of sociodemographic and medical factors, higher levels of education and wealth, and lower levels of depressive symptoms, accounted for some of the US cognitive advantage. US adults were also more likely to be taking medications for hypertension, and hypertension treatment was associated with significantly better cognitive function in the US, but not in England (P = .014 for treatment × country interaction).</p> <p>Conclusion</p> <p>Despite methodological differences in the administration of the surveys in the two countries, US adults aged ≥ 65 appeared to be cognitively healthier than English adults, even though they had a higher burden of cardiovascular risk factors and disease. Given the growing number of older adults worldwide, future cross-national studies aimed at identifying the medical and social factors that might prevent or delay cognitive decline in older adults would make important and valuable contributions to public health.</p
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