1,112 research outputs found

    Daily Sleep Quality is Associated with Daily Cognition in Late-Life

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    Background: Older adults often face sleep disturbance or cognitive decline that goes beyond the scope of normal aging. The present study examined the relationship between self-reported sleep quality and self-reported daytime attention in a community-dwelling sample of older men at the between-persons and within-persons levels of association. Methods: Thirty-eight participants (M age =75.36 years, SD age =7.51 years, range=66-90 years) completed a twice-daily sleep diary for one week. Sleep quality and attention were assessed using a single-item 0-10 rating scales from the morning diary (“How was the quality of your sleep last night?”) and from the evening diary (“How was your attention today?”). A two-level multilevel model was parameterized with days nested within individuals to examine whether nightly sleep quality predicts an individual’s daily attention rating. Results: A multilevel model predicting self-reported attention revealed (1) older individuals who reported better sleep quality reported having better daily attention [Beta=0.64, t(248.15)=10.12, p\u3c0.001] and (2) following a day of above-average sleep quality, older individuals experienced above-average attention [Beta=0.16, t(259.79)=2.75, p=.006]. Conclusion: Not only was overall sleep quality associated with self-reported attention, but a good night\u27s sleep was associated with better self-reported next-day attention. Results point to the potential importance of fluctuations in sleep quality for daytime functioning. Interventions aimed at improving nightly sleep consistency may be worth exploring as methods to improve daytime cognitive functioning in older adults. Support: This work was supported by the Sleep Research Society Foundation/Jazz Pharmaceuticals (001JP13, PI: Dzierzewski) and by the National Institute on Aging of the National Institutes of Health under Award Number K23AG049955 (PI: Dzierzewski), and National Heart Lung and Blood Institute at the National Institutes of Health under award number K24HL143055 (PI: Martin). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or the Department of Veterans Affairs.https://scholarscompass.vcu.edu/gradposters/1089/thumbnail.jp

    Aromatic/aliphatic diamine derivatives for advanced compositions and polymers

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    Novel compositions of matter comprise certain derivatives of 9,9-dialkyl fluorene diamine (AFDA). The resultant compositions, whether compositions of matter or monomers that are subsequently incorporated into a polymer, are unique and useful in a variety of applications. Useful applications of AFDA-based material include heavy ion radiation shielding components and components of optical and electronic devices

    Ovarian Hormones and Cerebral Hemodynamics During Upright Tilt

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    The cerebral vasculature is a specific target for ovarian hormones. Estrogens in particular activate endothelial factors that decrease vessel tone and increase blood flow. Changes in cerebral blood flow across the menstrual cycle could underlie the observation that women experience orthostatic instability more often than men, but the influence of ovarian hormone levels on cerebral hemodynamics in the upright posture is unclear. PURPOSE: To test the hypothesis that cerebral blood velocity and cerebral autoregulatory capacity change in parallel with ovarian hormone concentrations. METHODS: Nine healthy eumenorrheic women (mean age 24 ± 1 yr, height 166 ± 3 cm, weight 68 ± 2 kg; mean ± SE) were studied during the early and late follicular (EF and LF) and early and late luteal (EL and LL) phases of the menstrual cycle. We recorded the ECG, beat-by-beat arterial pressure, end-tidal CO2, and cerebral blood velocity from the middle cerebral artery (transcranial Doppler). Plasma ovarian hormone concentrations were assessed with high performance liquid chromatography. Subjects breathed in time to a metronome for 10 min (15 breaths/min) in the supine position, and were then tilted head-up to 70° for an additional 10 min of controlled breathing. Cerebral autoregulation was assessed in the frequency domain with cross-spectral analysis of mean arterial pressure (MAP) and mean CBV within the frequency range of 0.07-0.2 Hz. RESULTS: Upright tilt decreased CBV (supine 74 ± 1.7; tilt 65 ± 1.8 cm ∙ s-1; P=.005 pooled across phases) and end-tidal CO2 (P\u3c.001) but did not affect MAP. Coherence increased from .45 ± .02 to .67 ± .03 with tilt (P\u3c .001 pooled across phases) and was significantly higher during LF (.61 ± .03) compared with LL (.48 ± .03; P = .04). Lower coherence during LL compared with LF was associated with higher concentrations of progesterone (P \u3c .001). CONCLUSIONS: Upright tilt decreases CBV, and the magnitude of reduction is not related to ovarian hormone concentrations. Lower coherence during LL compared with LF suggests improved autoregulatory capacity mediated by higher concentrations of progesterone. These results have implications for orthostatic stability in women

    Sensitivity Studies of Forty-Four Strains Mastitis Producing Organisms to Chloramphenicol

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    The purpose of this investigation was to obtain an indication of the possible value of chloramphenicol in the treatment of bovine mastitis. In vitro tests were run to determine what concentrations of the antibiotic are effective in inhibiting the growth of organisms isolated from field cases of bovine mastitis

    Arterial Pulse Wave Velocities are Unchanged Following 12 Weeks of Circuit Weight Training

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    Arterial stiffness is decreased after vigorous endurance training and increased after high-intensity resistance training. The effects of a combined program of moderate endurance and resistance exercise on arterial stiffness have not been determined. PURPOSE: To determine whether12 weeks of circuit weight training will decrease both central and peripheral arterial stiffness as estimated from pulse wave velocity (PWV). METHODS: Thirteen males and eight females (age 22 ± 2, height 162 ± 8 cm, weight 78 ± 20 kg) were assigned to control (n = 10) or exercise (n = 11) groups. Aerobic capacity and muscular strength were assessed before and at the end of the 12 week period. Arterial pressures and PWV (Doppler) were recorded every four weeks. Velocities from the carotid to femoral artery and from the femoral to dorsalis pedis artery were used as estimates of central and peripheral stiffness. RESULTS: Muscular strength increased by 26% (P = .001) and VO2 max increased by 17% (P = .06) following circuit training in the exercise group, but was unchanged for controls. Circuit weight training did not affect arterial pressures, (systolic = 117 ± 3, diastolic = 74 ± 3 mmHg; pooled across groups), or central and peripheral PWV (central PWV = 6.2 ± 0.6, peripheral PWV = 9.5 ± 0.7 m ∙ s-1; pooled across groups). CONCLUSIONS: In contrast to other reports of increases in arterial stiffness following high-intensity resistance training, increases in muscular strength following moderate-intensity exercise in the current study were not associated with increased arterial stiffness. Circuit training may be an appropriate exercise prescription to increase muscular strength for patients at risk for peripheral artery disease

    Thermal Conductivity of Polymer/Nano-filler Blends

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    To improve the thermal conductivity of an ethylene vinyl acetate copolymer, Elvax 260 was compounded with three carbon based nano-fillers. Multiwalled carbon nanotubes (MWCNT), vapor grown carbon nanofibers (CNF) and expanded graphite (EG) were investigated. In an attempt to improve compatibility between the Elvax and nanofillers, MWCNTs and EGs were modified through non covalent and covalent attachment of alkyl groups. Ribbons were extruded to form samples in which the nanofillers were aligned, and samples were also fabricated by compression molding in which the nano-fillers were randomly oriented. The thermal properties were evaluated by DSC and TGA, and mechanical properties of the aligned samples were determined by tensile testing. The degree of dispersion and alignment of the nanoparticles were investigated using high-resolution scanning electron microscopy. Thermal conductivity measurements were performed using a Nanoflash technique. The thermal conductivity of the samples was measured in both the direction of alignment as well as perpendicular to that direction. The results of this study will be presented

    Major Merger Galaxy Pairs at z = 0: Dust Properties and Companion Morphology

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    We present an analysis of dust properties of a sample of close major-merger galaxy pairs selected by K_s magnitude and redshift. The pairs represent the two populations of spiral–spiral (S+S) and mixed morphology spiral–elliptical (S+E). The Code Investigating GALaxy Emission software is used to fit dust models to the Two Micron All Sky Survey, Wide-Field Infrared Survey Explorer, and Herschel flux density measurements, and to derive the parameters describing the polycyclic aromatic hydrocarbons contribution, interstellar radiation field, and photodissociation regions. Model fits verify our previous Spitzer Space Telescope analysis that S+S and S+E pairs do not have the same level of enhancement of star formation and differ in dust composition. The spirals of mixed-morphology galaxy pairs do not exhibit the enhancements in interstellar radiation field and therefore dust temperature for spirals in S+S pairs in contrast to what would be expected according to standard models of gas redistribution due to encounter torques. This suggests the importance of the companion environment/morphology in determining the dust properties of a spiral galaxy in a close major-merger pair
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