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Search Results: 1 - 10 of 212569 matches for " Lisa L. Barnes "
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Associations between Quantitative Mobility Measures Derived from Components of Conventional Mobility Testing and Parkinsonian Gait in Older Adults
Aron S. Buchman, Sue E. Leurgans, Aner Weiss, Veronique VanderHorst, Anat Mirelman, Robert Dawe, Lisa L. Barnes, Robert S. Wilson, Jeffrey M. Hausdorff, David A. Bennett
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0086262
Abstract: Objective To provide objective measures which characterize mobility in older adults assessed in the community setting and to examine the extent to which these measures are associated with parkinsonian gait. Methods During conventional mobility testing in the community-setting, 351 ambulatory non-demented Memory and Aging Project participants wore a belt with a whole body sensor that recorded both acceleration and angular velocity in 3 directions. We used measures derived from these recordings to quantify 5 subtasks including a) walking, b) transition from sit to stand, c) transition from stand to sit, d) turning and e) standing posture. Parkinsonian gait and other mild parkinsonian signs were assessed with a modified version of the original Unified Parkinson’s Disease Rating Scale (mUPDRS). Results In a series of separate regression models which adjusted for age and sex, all 5 mobility subtask measures were associated with parkinsonian gait and accounted for 2% to 32% of its variance. When all 5 subtask measures were considered in a single model, backward elimination showed that measures of walking sit to stand and turning showed independent associations with parkinsonian gait and together accounted for more than 35% of its variance. Cross-validation using data from a 2nd group of 258 older adults showed similar results. In similar analyses, only walking was associated with bradykinesia and sway with tremor. Interpretation Quantitative mobility subtask measures vary in their associations with parkinsonian gait scores and other parkinsonian signs in older adults. Quantifying the different facets of mobility has the potential to facilitate the clinical characterization and understanding the biologic basis for impaired mobility in older adults.
Systemic Inflammation in Non-Demented Elderly Human Subjects: Brain Microstructure and Cognition
Konstantinos Arfanakis, Debra A. Fleischman, Giorgia Grisot, Christopher M. Barth, Anna Varentsova, Martha C. Morris, Lisa L. Barnes, David A. Bennett
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0073107
Abstract: The purpose of this study was to test the hypothesis that higher levels of systemic inflammation in a community sample of non-demented subjects older than seventy years of age are associated with reduced diffusion anisotropy in brain white matter and lower cognition. Ninety-five older persons without dementia underwent detailed clinical and cognitive evaluation and magnetic resonance imaging, including diffusion tensor imaging. Systemic inflammation was assessed with a composite measure of commonly used circulating inflammatory markers (C-reactive protein and tumor necrosis factor-alpha). Tract-based spatial statistics analyses demonstrated that diffusion anisotropy in the body and isthmus of the corpus callosum was negatively correlated with the composite measure of systemic inflammation, controlling for demographic, clinical and radiologic factors. Visuospatial ability was negatively correlated with systemic inflammation, and diffusion anisotropy in the body and isthmus of the corpus callosum was shown to mediate this association. The findings of the present study suggest that higher levels of systemic inflammation may be associated with lower microstructural integrity in the corpus callosum of non-demented elderly individuals, and this may partially explain the finding of reduced higher-order visual cognition in aging.
Measurement of microbial activity in soil by colorimetric observation of in situ dye reduction: an approach to detection of extraterrestrial life
Ronald L Crawford, Andrzej Paszczynski, Qingyong Lang, Daniel P Erwin, Lisa Allenbach, Giancarlo Corti, Tony J Anderson, I Francis Cheng, Chien Wai, Bruce Barnes, Richard Wells, Touraj Assefi, Mohammad Mojarradi
BMC Microbiology , 2002, DOI: 10.1186/1471-2180-2-22
Abstract: Here we used Earth-derived soils to develop a related life detection system based on direct observation of a biological redox signature. We measured the ability of soil microbial communities to reduce artificial electron acceptors. Living organisms in pure culture and those naturally found in soil were shown to reduce 2,3-dichlorophenol indophenol (DCIP) and the tetrazolium dye 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide inner salt (XTT). Uninoculated or sterilized controls did not reduce the dyes. A soil from Antarctica that was determined by chemical signature and DNA analysis to be sterile also did not reduce the dyes.Observation of dye reduction, supplemented with extraction and identification of only a few specific signature redox-active biochemicals such as porphyrins or quinones, provides a simplified means to detect a signature of life in the soils of other planets or their moons.The detection of microbial life in extraterrestrial locations is an important goal of human exploration of space because of ecological and health concerns about possible contamination of other planets with earthly organisms, and vice versa [1,2]. Several indirect methods for detecting extraterrestrial life have been proposed in the prior literature. These include (a) examining the ratios of stable isotopes in important elements such as carbon and sulphur for discrimination against heavy isotopes and selective use of the lighter isotopes, (b) microscopic observations of highly organized or specifically-shaped structures [3,4], (c) examination of soils for the presence of specific types of organic moieties [5], and (d) the detection of chiral molecules in extraterrestrial samples [6-12].Previously we suggested a thermodynamic approach to the detection of life. Since living entities require a continual source of usable energy, we should be able to detect a chemical signature of life in the form of mixtures of redox molecules such as porphyrins, quinones, and
Stabilizer Codes for Continuous-variable Quantum Error Correction
Richard L. Barnes
Physics , 2004,
Abstract: A generalization of the stabilizer code construction presented by Gottesman is described, which allows for the construction of quantum error-correcting codes for continuous-variable systems. This formalism describes all continuous-variable codes presented to date, and can be used to construct new codes based on discrete-variable codes or classical codes. We use it to describe the nine-mode code given by Lloyd and Slotine, and a five-mode code described by Braunstein. In addition, we construct a new continuous-variable code based an code of Gottesman which encodes three logical modes of information into eight physical modes and corrects one error. This generalization is a step toward an independent understanding of continuous-variable quantum information and a theory of fault-tolerant quantum information processing.
Juvenile rainbow trout responses to diets containing distillers dried grain with solubles, phytase, and amino acid supplements  [PDF]
Michael E. Barnes, Michael L. Brown, Kurt A. Rosentrater
Open Journal of Animal Sciences (OJAS) , 2012, DOI: 10.4236/ojas.2012.22011
Abstract: Distillers dried grain with solubles (DDGS) was evaluated in juvenile Shasta-strain rainbow trout Oncorhynchus mykiss diets during a 36-day feeding trial. Two experimental diets containing either 10% or 20% DDGS with supplemented amino acids (lysine, methionine, isoleucine, and his-tidine) and phytase were compared to a fish meal-only control diet. Tanks of trout receiving diets containing either concentration of DDGS weighed significantly less at the end of the trial and had significantly poorer feed conversion ratios than tanks of fish being fed the fish meal- only control. There was no significant difference in individual fish length, weight, condition factor, or any fish health measurements among diet treatments. Both the hepatosomatic index and viscerosomatic index were significantly less in the fish fed 10% DDGS than those fed the control diet. Body fat was significantly greater in the fish receiving 20% DDGS compared to fish fed either of the other two diets. Fillet composition, as determined by crude protein, crude lipid, ash, and water, was not significantly different among fish reared on any of the diets. There was also no significant difference in estimated protein digestibility coefficients among fish receiving any of the diets. The results suggest that DDGS, even if supplemented with essential amino acids and phytase, will lead to decreased juvenile rainbow trout growth at dietary concentrations of at 10% or greater.
Neural entrainment to rhythmic speech in children with developmental dyslexia
Alan J. Power,Natasha Mead,Lisa Barnes,Usha Goswami
Frontiers in Human Neuroscience , 2013, DOI: 10.3389/fnhum.2013.00777
Abstract: A rhythmic paradigm based on repetition of the syllable “ba” was used to study auditory, visual, and audio-visual oscillatory entrainment to speech in children with and without dyslexia using EEG. Children pressed a button whenever they identified a delay in the isochronous stimulus delivery (500 ms; 2 Hz delta band rate). Response power, strength of entrainment and preferred phase of entrainment in the delta and theta frequency bands were compared between groups. The quality of stimulus representation was also measured using cross-correlation of the stimulus envelope with the neural response. The data showed a significant group difference in the preferred phase of entrainment in the delta band in response to the auditory and audio-visual stimulus streams. A different preferred phase has significant implications for the quality of speech information that is encoded neurally, as it implies enhanced neuronal processing (phase alignment) at less informative temporal points in the incoming signal. Consistent with this possibility, the cross-correlogram analysis revealed superior stimulus representation by the control children, who showed a trend for larger peak r-values and significantly later lags in peak r-values compared to participants with dyslexia. Significant relationships between both peak r-values and peak lags were found with behavioral measures of reading. The data indicate that the auditory temporal reference frame for speech processing is atypical in developmental dyslexia, with low frequency (delta) oscillations entraining to a different phase of the rhythmic syllabic input. This would affect the quality of encoding of speech, and could underlie the cognitive impairments in phonological representation that are the behavioral hallmark of this developmental disorder across languages.
Galaxy Mergers and the Mass-Metallicity Relation: Evidence for Nuclear Metal Dilution and Flattened Gradients from Numerical Simulations
David S. N. Rupke,Lisa J. Kewley,Joshua E. Barnes
Physics , 2010, DOI: 10.1088/2041-8205/710/2/L156
Abstract: Recent results comparing interacting galaxies to the mass-metallicity relation show that their nuclear oxygen abundances are unexpectedly low. We present analysis of N-body/SPH numerical simulations of equal-mass mergers that confirm the hypothesis that these underabundances are accounted for by radial inflow of low-metallicity gas from the outskirts of the two merging galaxies. The underabundances arise between first and second pericenter, and the simulated abundance dilution is in good agreement with observations. The simulations further predict that the radial metallicity gradients of the disk galaxies flatten shortly after first passage, due to radial mixing of gas. These predictions will be tested by future observations of the radial metallicity distributions in interacting galaxies.
Proteolysis of proBDNF Is a Key Regulator in the Formation of Memory
Philip Barnes, Kerrie L. Thomas
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0003248
Abstract: It is essential to understand the molecular processes underlying long-term memory to provide therapeutic targets of aberrant memory that produce pathological behaviour in humans. Under conditions of recall, fully-consolidated memories can undergo reconsolidation or extinction. These retrieval-mediated memory processes may rely on distinct molecular processes. The cellular mechanisms initiating the signature molecular events are not known. Using infusions of protein synthesis inhibitors, antisense oligonucleotide targeting brain-derived neurotrophic factor (BDNF) mRNA or tPA-STOP (an inhibitor of the proteolysis of BDNF protein) into the hippocampus of the awake rat, we show that acquisition and extinction of contextual fear memory depended on the increased and decreased proteolysis of proBDNF (precursor BDNF) in the hippocampus, respectively. Conditions of retrieval that are known to initiate the reconsolidation of contextual fear memory, a BDNF-independent memory process, were not correlated with altered proBDNF cleavage. Thus, the processing of BDNF was associated with the acquisition of new information and the updating of information about a salient stimulus. Furthermore, the differential requirement for the processing of proBDNF by tPA in distinct memory processes suggest that the molecular events actively engaged to support the storage and/or the successful retrieval of memory depends on the integration of ongoing experience with past learning.
The Impact of Omega-3 Fatty Acid Use on the Risk of Atrial Fibrillation in Patients with Cardiovascular Disease  [PDF]
Brian J. Barnes, Patricia A. Howard, Scott Solomon, Warren Chen, James L. Vacek
International Journal of Clinical Medicine (IJCM) , 2011, DOI: 10.4236/ijcm.2011.21006
Abstract: Fish oils containing omega-3 fatty acids (OM3FA) are widely prescribed in the management of dyslipidemia. An asso-ciation between OM3FA and reduced risk of atrial fibrillation (AF) has been proposed. We examined the impact of OM3FA exposure on the risk of developing AF in patients with cardiovascular disease. Data was obtained from elec-tronic medical records of patients seen by our cardiology service between 2005 and 2007. Patients were excluded if AF developed prior to, or on the day of, OM3FA exposure. A total of 11,360 subjects were eligible for analyses. Subjects exposed to OM3FA were at higher risk for AF. Nearly all AF risk factors were significantly more prevalent in the OM3FA exposed group. As expected, those prescribed OM3FA were also more likely to be prescribed statins, ACE in-hibitors, aspirin, and beta blockers. AF occurred in 8.5% (221/2600) of OM3FA exposed subjects and 23.5% (2054/8760) of those not exposed. After controlling for AF risk factors, OM3FA exposed subjects were 74% less likely to develop AF than those not exposed to OM3FA (odds ratio 0.26, 95%CI 0.22-0.30, p < 0.0001). After controlling for risk factors for AF, OM3FA use is significantly associated with a reduced risk for AF in patients with cardiovascular disease. Potential mechanisms which may explain the ability of OM3FAs to reduce AF include its anti-inflammatory and anti-arrhythmic properties. The optimal dose of OM3FA to prevent AF is unknown and warrants prospective as-sessment in a randomized controlled trial of OM3FAs powered to detect significant differences in AF.
An initial investigation replacing fish meal with a commercial fermented soybean meal product in the diets of juvenile rainbow trout  [PDF]
Michael E. Barnes, Michael L. Brown, Kurt A. Rosentrater, Jason R. Sewell
Open Journal of Animal Sciences (OJAS) , 2012, DOI: 10.4236/ojas.2012.24033
Abstract: The inclusion of PepSoyGen (PSG), a commercially-available fermented soybean meal product, was evaluated with juvenile rainbow trout, Oncorhynchus mykiss in an initial 70-day feeding trial, with a supplemental trial involving a subset of the experimental diets continuing for an additional 40 d. Six diets containing 0%, 10%, 20%, 30%, 40%, or 50% PSG, with the PSG directly replacing fish meal, were used in the first trial. There were no significant differences in weight gain or feed conversion ratio between the fish meal-based control diet and diets containing up to 30% PSG. However, weight gain was significantly reduced and feed conversion ratio significantly increased with the 40% and 50% PSG diets. No health assessment differences were observed in fish receiving any of the diets, and no evidence of gross gut inflammation was evident. There were no significant differences in weight gain or feed conversion ratio among the four dietary treatments ranging from 0% to 30% PSG which were fed for an additional 40 d after the initial 70-d trial (110 days total). Based on these results, juvenile rainbow trout diets can contain up to 30% PSG without any loss of rearing performance, thereby replacing at least 60% of the fish meal.
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