5,632 research outputs found

    Relationship between antihypertensive medications and cognitive impairment: Part II. Review of Physiology and animal studies

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    Purpose of Review There is an established association between hypertension and increased risk of poor cognitive performance and dementia including Alzheimer’s disease; however, associations between antihypertensive medications (AHM) and dementia risk are less clear. An increased interest in AHM has resulted in expanding publications; however, none of the recent reviews provide comprehensive review. Our extensive review includes 24 mechanistic animal and human studies published over the last 5 years assessing relationship between AHM and cognitive function. Recent Findings All classes of AHM showed similar result patterns in animal studies. The mechanism by which AHM exert their effect was extensively studied by evaluating well-established pathways of AD disease process, including amyloid beta (Aβ), vascular, oxidative stress and inflammation pathways, but only few studies evaluated the blood pressure lowering effect on the AD disease process. Summary Methodological limitations of the studies prevent comprehensive conclusions prior to further work evaluating AHM in animals and larger human observational studies, and selecting those with promising results for future RCTs

    An improved atomic hydrogen frequency and time standard

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    Use of a large bulb, long-multipole magnet, automatic tuner and aluminum cavity provides an improved hydrogen maser which is accurate over long periods of time and suitable for tracking station environments

    Relationship between antihypertensive medications and cognitive impairment: Part I. review of human studies and clinical trials

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    Purpose of review: There is an established association between hypertension and increased risk of poor cognitive performance and dementia including Alzheimer’s disease; however, associations between antihypertensive medications (AHMs) and dementia risk are less consistent. An increased interest in AHM has resulted in expanding publications; however, none of the recent reviews are comprehensive. Our extensive review includes 15 observational and randomized controlled trials (RCTs) published over the last 5 years, assessing the relationship between AHM and cognitive impairment. Recent findings: All classes of AHM showed similar result patterns in human studies with the majority of study results reporting point estimates below one and only a small number of studies (N = 15) reporting statistically significant results in favor of a specific class. Summary: Only a small number of studies reported statistically significant results in favor of a specific class of AHM. Methodological limitations of the studies prevent definitive conclusions. Further work is now needed to evaluate the class of AHM and cognitive outcomes in future RCTs, with a particular focus on the drugs with the promising results in both animals and human observational studies

    Quantum Heisenberg antiferromagnetic chains with exchange and single--ion anisotropies

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    Using density matrix renormalization group calculations, ground state properties of the spin-1 Heisenberg chain with exchange and quadratic single-ion anisotropies in an external field are studied, for special choices of the two kinds of anisotropies. In particular, the phase diagram includes antiferromagnetic, spin-liquid (or spin-flop), (10), and supersolid (or biconical) phases. Especially, new features of the spin-liquid and supersolid phases are discussed. Properties of the quantum chains are compared to those of corresponding classical spin chains.Comment: 4 pages, 5 figures, ICM0

    Precision CW laser automatic tracking system investigated

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    Precision laser tracker capable of tracking a low acceleration target to an accuracy of about 20 microradians rms is being constructed and tested. This laser tracking has the advantage of discriminating against other optical sources and the capability of simultaneously measuring range

    Aging affects two modes of nanoleakage expression in bonded dentin

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    Water sorption into resin-dentin interfaces precedes hydrolytic degradation. We hypothesized that these processes are morphologically manifested by the uptake of ammoniacal silver nitrate, which is thought to trace hydrophilic domains and water-filled channels within matrices. Water sorption is thought to be nonuniform and can be traced by the use of silver nitrate. Human teeth bonded with an experimental filled-adhesive were aged in artificial saliva (experimental) or non-aqueous mineral oil (control). Specimens retrieved for up to a 12-month period were immersed in 50 wt% ammoniacal silver nitrate and examined by transmission electron microscopy for identification of the changes in their silver uptake. Reticular silver deposits initially identified within the bulk of hybrid layers in the experimental group were gradually reduced over time, but were subsequently replaced by similar deposits that were located along the hybrid layer-adhesive interface. Silver uptake in water-binding domains of the adhesive layers increased with aging, resulting in water tree formation. These water-filled channels may act as potential sites for hydrolytic degradation of resin-dentin bonds.published_or_final_versio

    Validation of the CogDrisk Instrument as Predictive of Dementia in Four General Community-Dwelling Populations

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    Background: Lack of external validation of dementia risk tools is a major limitation for generalizability and translatability of prediction scores in clinical practice and research. Objectives: We aimed to validate a new dementia prediction risk tool called CogDrisk and a version, CogDrisk-AD for predicting Alzheimer’s disease (AD) using cohort studies. Design, Setting, Participants and Measurements: Four cohort studies were identified that included majority of the dementia risk factors from the CogDrisk tool. Participants who were free of dementia at baseline were included. The predictors were component variables in the CogDrisk tool that include self-reported demographics, medical risk factors and lifestyle habits. Risk scores for Any Dementia and AD were computed and Area Under the Curve (AUC) was assessed. To examine modifiable risk factors for dementia, the CogDrisk tool was tested by excluding age and sex estimates from the model. Results: The performance of the tool varied between studies. The overall AUC and 95% CI for predicting dementia was 0.77 (0.57, 0.97) for the Swedish National study on Aging and Care in Kungsholmen, 0.76 (0.70, 0.83) for the Health and Retirement Study - Aging, Demographics and Memory Study, 0.70 (0.67,0.72) for the Cardiovascular Health Study Cognition Study, and 0.66 (0.62,0.70) for the Rush Memory and Aging Project. Conclusions: The CogDrisk and CogDrisk-AD performed well in the four studies. Overall, this tool can be used to assess individualized risk factors of dementia and AD in various population settings

    Efficacy of entomopathogenic nematodes for control of large pine weevil, Hylobius abietis: effects of soil type, pest density and spatial distribution

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    The large pine weevil Hylobius abietis (L.), LPW, is a major pest of trees in replanted coniferous forests in northern Europe. The use of entomopathogenic nematodes (EPNs) applied against developing stages for population suppression is increasingly recognized as an effective alternative to plant protection using chemical pesticides. Here, we report results from a series of trials we conducted over 2 years using two species of EPN, Steinernema carpocapsae (Weiser) and Heterorhabitis downesi (Stock, Griffin, and Burnell) with different foraging strategies. Trials were conducted at lodgepole pine sites in Ireland on both mineral and peat soil type. EPN suspension was applied to the stumps of felled pine trees, and EPN efficacy was determined afterwards by directly assessing parasitism rates after debarking one quarter of the stumps and by collecting emerging adult weevils from traps erected over other treated and control stumps. Our results suggest that both species of EPN are equally effective in suppressing LPW populations to below the current, informal thresholds of economic damage. EPN were equally efficient in controlling LPW in peat and in mineral (lithosols/regosols and acid brown earth/brown podzolics) soils. Weevil density and distribution within pine stumps in peat versus mineral sites can explain patterns of LPW parasitism and suppression. Our results also suggest that infestation level (number of weevils per stump) can be an important factor in forecasting EPN application success as there is evidence of negative density-dependent parasitism when weevil densities were high. © 2016 Springer-Verlag Berlin Heidelber
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