832 research outputs found

    Neurocognitive Functioning in Parkinsons Disease Patients: Assessing the Unique Contributions of Depression and Fatigue While Controlling for Disease Severity

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    Background: While individuals diagnosed with Parkinsons disease (PD) often experience cognitive deficits, depression, and fatigue, the relationships among these non-motor sequelae throughout the progression of the disease are unclear. Objective: To examine the relationships among disease severity, depression, and fatigue and investigate the independent contributions of depression and fatigue to a composite measure of cognitive functioning, when controlling for disease severity in PD patients. Methods: A mixed retrospective and prospective sample of PD patients completed a comprehensive neuropsychological battery, as well as self-report measures of depression and fatigue. Cognitive functioning was represented by a summary statistic, or cognitive impairment index (CII). A hierarchal linear regression model, controlling for disease severity, examined the unique contributions of depression and fatigue on cognitive functioning. A Pearson correlation examined the relationship between depression and fatigue. Results: At step one, disease severity significantly contributed to the model, F(1, 41) = 48.06, p \u3c .001, accounting for 52.8% of the variance in cognitive functioning. Introduction of depression and fatigue explained an additional 7.2% of the variance and this change in R2 was significant F(2,39) = 4.68, p \u3c 0.05. Only depression continued to be a significant contributor beyond disease severity, t = 2.21, = 0.24, p \u3c 0.05 and the change in the model was significant, F(1, 40) = 4.88, p \u3c 0.05, R2 change = 0.05Conclusions: Findings suggest that depression is uniquely associated with cognitive functioning observed in PD patients independent of disease severity or level of fatigue. Interventions targeted towards depression may improve cognitive functioning

    Screening fungi isolated from historic Discovery Hut on Ross Island, Antarctica for cellulose degradation

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    To survive in Antarctica, early explorers of Antarctica's Heroic Age erected wooden buildings and brought in large quantities of supplies. The introduction of wood and other organic materials may have provided new nutrient sources for fungi that were indigenous to Antarctica or were brought in with the materials. From 30 samples taken from Discovery Hut, 156 filamentous fungi were isolated on selective media. Of these, 108 were screened for hydrolytic activity on carboxymethyl cellulose, of which 29 demonstrated activities. Endo-1, 4-Ī²-glucanase activity was confirmed in the extracellular supernatant from seven isolates when grown at 4Ā°C, and also when they were grown at 15Ā°C. Cladosporium oxysporum and Geomyces sp. were shown to grow on a variety of synthetic cellulose substrates and to use cellulose as a nutrient source at temperate and cold temperatures. The research findings from the present study demonstrate that Antarctic filamentous fungi isolated from a variety of substrates (wood, straw, and food stuffs) are capable of cellulose degradation and can grow well at low temperatures

    Chromospheric Activity of HAT-P-11: an Unusually Active Planet-Hosting K Star

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    Kepler photometry of the hot Neptune host star HAT-P-11 suggests that its spot latitude distribution is comparable to the Sun's near solar maximum. We search for evidence of an activity cycle in the CaII H & K chromospheric emission SS-index with archival Keck/HIRES spectra and observations from the echelle spectrograph on the ARC 3.5 m Telescope at APO. The chromospheric emission of HAT-P-11 is consistent with a ā‰³10\gtrsim 10 year activity cycle, which plateaued near maximum during the Kepler mission. In the cycle that we observed, the star seemed to spend more time near active maximum than minimum. We compare the logā”RHKā€²\log R^\prime_{HK} normalized chromospheric emission index of HAT-P-11 with other stars. HAT-P-11 has unusually strong chromospheric emission compared to planet-hosting stars of similar effective temperature and rotation period, perhaps due to tides raised by its planet.Comment: 16 pages, 8 figures; accepted to the Astrophysical Journa

    Using hydrogeochemical and ecohydrologic responses to understand epikarst process in semi-arid systems, Edwards plateau, Texas, USA

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    The epikarst is a permeable boundary between surface and subsurface environments and can be conceptualized as the vadose critical zone of epigenic karst systems which have not developed under insoluble cover. From a hydrologic perspective, this boundary is often thought of as being permeable in one direction only (down), but connectivity between the flow paths of water through the epikarst and the root systems of woody plants means that water moves both up and down across the epikarst. However, the dynamics of these flows are complex and highly dependent on variability in the spatial structure of the epikarst, vegetation characteristics, as well as temporal variability in precipitation and evaporative demand. Here we summarize insights gained from working at several sites on the Edwards Plateau of Central Texas, combining isotopic, hydrogeochemical, and ecophysiological methodologies. 1) Dense woodland vegetation at sites with thin to absent soils (0-30 cm) is in part supported by water uptake from the epikarst. 2) However, tree transpiration typically becomes water-limited in dry summers, suggesting that the plant-available fraction of stored water in the epikarst depletes quickly, even when sustained cave drip rates indicate that water is still present in the epikarst. 3) Flow paths for water that feeds cave drips become rapidly disconnected from the evaporation zone of the epikarst and out of reach for plant roots. 4) Deep infiltration and recharge does not occur in these systems without heavy or continuous precipitation that exceeds some threshold value. Thresholds are strongly correlated with antecedent potential evapotranspiration and rainfall, suggesting control by the moisture status of the epikarst evapotranspiration zone. The epikarst and unsaturated zone in this region can be conceptualized as a variably saturated system with storage in fractures, matrix porosity, and in shallow perched aquifers, most of which is inaccessible to the root systems of trees, although woody vegetation may control recharge thresholds.Keywords: hydraulic disconnection, precipitation thresholds, root zone, plant water use, recharge, epikarst storage, barometric pressure.DOI: 10.3986/ac.v42i2-3.67

    IgG Responses to Tissue-Associated Antigens as Biomarkers of Immunological Treatment Efficacy

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    We previously demonstrated that IgG responses to a panel of 126 prostate tissue-associated antigens are common in patients with prostate cancer. In the current report we questioned whether changes in IgG responses to this panel might be used as a measure of immune response, and potentially antigen spread, following prostate cancer-directed immune-active therapies. Sera were obtained from prostate cancer patients prior to and three months following treatment with androgen deprivation therapy (n = 34), a poxviral vaccine (n = 31), and a DNA vaccine (n = 21). Changes in IgG responses to individual antigens were identified by phage immunoblot. Patterns of IgG recognition following three months of treatment were evaluated using a machine-learned Bayesian Belief Network (ML-BBN). We found that different antigens were recognized following androgen deprivation compared with vaccine therapies. While the number of clinical responders was low in the vaccine-treated populations, we demonstrate that ML-BBN can be used to develop potentially predictive models

    Characterizing Solid Electrolyte Interphase on Sn Anode in Lithium Ion Battery

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    Tin (Sn) nanoparticle electrodes have been prepared and battery cycling performance has been investigated with 1.2 M LiPF6 in ethylene carbonate (EC) / diethyl carbonate (DEC) electrolyte (1:1, w/w) with and without added vinylene carbonate (VC) or fluoroethylene carbonate (FEC). Incorporation of either VC or FEC improves the capacity retention of Sn nanoparticle electrodes although incorporation of VC also results in a significant increase in cell impedance. The best electrochemical performance was observed with electrolyte containing 10% of added FEC. In order to develop a better understanding of the role of the electrolyte in capacity retention and solid electrolyte interface (SEI) structure, ex-situ surface analysis has been performed on cycled electrodes with infrared (IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and Hard XPS (HAXPES). The ex-situ analysis reveals a correlation between electrochemical performance, electrolyte composition, and SEI structure

    Time-richness and phosphatic microsteinkern accumulation in the Cincinnatian (Katian) Ordovician, USA: An example of polycyclic phosphogenic condensation

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    Millimeter-scale phosphatic steinkern preservation is a feature of the taxonomically enigmatic Early Cambrian ā€œsmall shelly faunasā€, but this style of preservation is not unique to the Cambrian; it is ubiquitous, if infrequently reported, from the Phanerozoic record. The polycyclic phosphogenic condensation (PPC) model envisions both the genesis and concentration of phosphatic microsteinkerns as natural outcomes of shell bed genesis through episodic sediment starvation. This model predicts that more reworked and condensed shell bed limestones will contain more phosphatic microsteinkerns, but that even the least reworked limestones may contain some phosphatic particles. We test this model through examination of vertical thin sections densely collected through a 10-meter interval from the classic Cincinnatian (upper Katian, middle Maysvillian North American Stage) upper Fairview Formation, Miamitown Shale, and lower Grant Lake formations at four localities near Cincinnati, Ohio. For each of approximately 50 distinguishable limestone depositional units in each locality, a 2ā€ÆƗā€Æ2ā€Æcm square was selected for study. Each square was assigned a textural classification (mud content of intergranular space) and a breakage rank (pristine to comminuted). Phosphatic particle distribution was quantified both by visual estimation and by particle counting, with counts ranging from none detected to over 1000 per 4ā€Æcm2. Our analyses show a strong positive relationship between phosphate content and both textural maturity and fragmentation. This positive relationship is consistent with the PPC model and confirms that textural maturity can reflect the degree of condensation as well as depth-related environmental energy. This finding suggests that shell bed processes of repeated deposition and reworking make a significant contribution to the generation and accumulation of phosphatic particles. If local-scale sedimentary processes and conditions can control this accumulation, temporal changes in phosphatic sediment deposition rates may be linked to earth changes more complexly than through changing ocean chemistry on a global scale

    Effect of Vinylene Carbonate and Fluoroethylene Carbonate on SEI Formation on Graphitic Anodes in Li-Ion Batteries

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    Binder free (BF) graphite electrodes were utilized to investigate the effect of electrolyte additives fluoroethylene carbonate (FEC) and vinylene carbonate (VC) on the structure of the solid electrolyte interface (SEI). The structure of the SEI has been investigated via ex-situ surface analysis including X-ray Photoelectron spectroscopy (XPS), Hard XPS (HAXPES), Infrared spectroscopy (IR) and transmission electron microscopy (TEM). The components of the SEI have been further investigated via nuclear magnetic resonance (NMR) spectroscopy of D2O extractions. The SEI generated on the BF-graphite anode with a standard electrolyte (1.2 M LiPF6 in ethylene carbonate (EC) / ethyl methyl carbonate (EMC), 3/7 (v/v)) is composed primarily of lithium alkyl carbonates (LAC) and LiF. Incorporation of VC (3% wt) results in the generation of a thinner SEI composed of Li2CO3, poly(VC), LAC, and LiF. Incorporation of VC inhibits the generation of LAC and LiF. Incorporation of FEC (3% wt) also results in the generation of a thinner SEI composed of Li2CO3, poly(FEC), LAC, and LiF. The concentration of poly(FEC) is lower than the concentration of poly(VC) and the generation of LAC is inhibited in the presence of FEC. The SEI appears to be a homogeneous film for all electrolytes investigated
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