2,739 research outputs found

    Lower-rim ferrocenyl substituted calixarenes: new electrochemical sensors for anions

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    New ferrocene substituted calix[4 and 5]arenes have been prepared and the crystal structure of a lower-rim substituted bis ferrocene calix[4]arene (7) has been elucidated. The respective ferrocene/ferrocenium redox-couples of compounds 6 (a calix[4]arene tetra ferrocene amide) and 8 (a calix[5]arene pentaferrocene amide) are shown to be significantly cathodically perturbed in the presence of anions by up to 160 mV in the presence of dihydrogen phosphate

    “Fecal microbiome in epidemiologic studies” - Letter

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    We congratulate Sinha et al. on their recent report (1) comparing fecal sample collection methods for epidemiologic studies of the gut microbiome. These data contribute to the increasing body of literature describing robust methodological frameworks for specimen collection and processing (2, 3). However, their claim that fixation of stool using RNAlater® results in “considerable changes to the microbiome diversity” contrasts with previous findings (2, 3), including those from their earlier reports (4, 5). We have previously demonstrated that self-collected stool stabilized with RNAlater® or other fixatives yields high fidelity and reproducibility in compositional profiling of DNA and RNA from shotgun sequence data, compared to immediately-frozen specimens (3). Additionally, fixation offers several distinct advantages crucial for large-scale population-based studies: a straightforward self-collection procedure; sample stabilization without deep-freezing during shipping, receiving, and processing; and versatility for multiple molecular analyses. The authors’ finding that specimens preserved in RNAlater® had poor correlation with immediately frozen specimens (1) could be explained, for example, by improper fixation resulting from an excess of specimen relative to preservative volume (1–2 g:2.5 ml, compared to the manufacturer-recommended ratio of 1 g:5–10 ml; Thermo Fisher Scientific Inc., Waltham, MA)

    EC08-137 Producing and Marketing Proso Millet in the Great Plains

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    Extension Circular 08-137 discusses producing and marketing proso millet in the great plains

    https://doi.org/10.3389/fnins.2017.00219 Decreasing Sedentary Behavior: Effects on Academic Performance, Meta-Cognition, and Sleep

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    There is growing interest in using activity workstations as a method of increasing light physical activity in normally sedentary environments. The current study (N = 117) compared the effects of studying in college students while slowly pedaling a stationary bike with a desktop with studying at traditional desks across 10 weeks in an academic semester. The students were assigned to study either on the stationary bike or at a traditional desk located in the campus library for a minimum of 2 h a week. During the 10 weeks, the students studied for tests or worked on other required academic activities while working at their assigned desk. In addition, the participants completed a pre survey, weekly surveys, and a post survey. We found that although students studying at the traditional desks reported more ease of studying and more effective studying than those using the stationary bikes, the two groups performed equally well on tests in an introductory psychology course. Moreover, the students using the traditional desks reported a decrease in sleep quality later in the semester while those using the activity workstation reported stable levels of sleep quality. The current results indicate that activity workstations could be implemented in university settings to encourage light physical activity without negatively affecting academic performance while providing possible long-term health and well-being benefits. Furthermore, the results suggests that activity workstations could be a means of combating sedentary behavior in environments where individuals are expected to sit either while waiting (e.g., doctor\u27s waiting rooms, airports) or when completing a necessary task (e.g., the workplace, educational settings)

    “Fecal microbiome in epidemiologic studies” - Letter

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    We congratulate Sinha et al. on their recent report (1) comparing fecal sample collection methods for epidemiologic studies of the gut microbiome. These data contribute to the increasing body of literature describing robust methodological frameworks for specimen collection and processing (2, 3). However, their claim that fixation of stool using RNAlater® results in “considerable changes to the microbiome diversity” contrasts with previous findings (2, 3), including those from their earlier reports (4, 5). We have previously demonstrated that self-collected stool stabilized with RNAlater® or other fixatives yields high fidelity and reproducibility in compositional profiling of DNA and RNA from shotgun sequence data, compared to immediately-frozen specimens (3). Additionally, fixation offers several distinct advantages crucial for large-scale population-based studies: a straightforward self-collection procedure; sample stabilization without deep-freezing during shipping, receiving, and processing; and versatility for multiple molecular analyses. The authors’ finding that specimens preserved in RNAlater® had poor correlation with immediately frozen specimens (1) could be explained, for example, by improper fixation resulting from an excess of specimen relative to preservative volume (1–2 g:2.5 ml, compared to the manufacturer-recommended ratio of 1 g:5–10 ml; Thermo Fisher Scientific Inc., Waltham, MA)

    Multiplex giant magnetoresistive biosensor microarrays identify interferon-associated autoantibodies in systemic lupus erythematosus.

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    High titer, class-switched autoantibodies are a hallmark of systemic lupus erythematosus (SLE). Dysregulation of the interferon (IFN) pathway is observed in individuals with active SLE, although the association of specific autoantibodies with chemokine score, a combined measurement of three IFN-regulated chemokines, is not known. To identify autoantibodies associated with chemokine score, we developed giant magnetoresistive (GMR) biosensor microarrays, which allow the parallel measurement of multiple serum antibodies to autoantigens and peptides. We used the microarrays to analyze serum samples from SLE patients and found individuals with high chemokine scores had significantly greater reactivity to 13 autoantigens than individuals with low chemokine scores. Our findings demonstrate that multiple autoantibodies, including antibodies to U1-70K and modified histone H2B tails, are associated with IFN dysregulation in SLE. Further, they show the microarrays are capable of identifying autoantibodies associated with relevant clinical manifestations of SLE, with potential for use as biomarkers in clinical practice

    The Importance of Heat Flux in Quasi-Parallel Collisionless Shocks

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    Collisionless plasma shocks are a common feature of many space and astrophysical systems and are sources of high-energy particles and non-thermal emission, channeling as much as 20\% of the shock's energy into non-thermal particles. The generation and acceleration of these non-thermal particles have been extensively studied, however, how these particles feed back on the shock hydrodynamics has not been fully treated. This work presents the results of self-consistent hybrid particle-in-cell simulations that show the effect of self-generated non-thermal particle populations on the nature of collisionless, quasi-parallel shocks. They contribute to a significant heat flux density upstream of the shock. Non-thermal particles downstream of the shock leak into the upstream region, taking energy away from the shock. This increases the compression ratio, slows the shock down, and flattens the non-thermal population's spectral index for lower Mach number shocks. We incorporate this into a revised theory for the Rankine-Hugoniot jump conditions that include this effect and it shows excellent agreement with simulations. The results have the potential to explain discrepancies between predictions and observations in a wide range of systems, such as inaccuracies of predictions of arrival times of coronal mass ejections and the conflicting radio and x-ray observations of intracluster shocks. These effects will likely need to be included in fluid modeling to accurately predict shock evolution.Comment: 7 pages, 3 figures, a lot of appendi

    An evolved disk surrounding the massive main sequence star MWC 297?

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    We present the results of the interferometric observations of the circumstellar disk surrounding MWC 297 in the continuum at 230 GHz (1.3 mm) and in the (J=2-1) rotational transitions of 12^{12}CO,13^{13}CO and C18^{18}O using the Submillimeter Array. At a distance of 250 pc, MWC 297 is one of the closest, young massive stars (M_{\star} \sim10 M_{\odot}) to us. Compact continuum emission is detected towards MWC 297 from which we estimate a disk mass (gas+dust) of 0.07 M_{\odot} and a disk radius of \le 80 AU. Our result demonstrates that circumstellar disks can survive around massive stars well into their main sequence phase even after they have become optically visible. Complementing our observations with the data compiled from the literature, we find the submm dust opacity index β\beta to be between 0.1 and 0.3. If the emission is optically thin, the low value of β\beta indicates the presence of relatively large grains in the disk, possibly because of grain growth. We do not detect any CO emission associated with the continuum source. We argue that the 13^{13}CO emission from the disk is likely optically thin, in which case, we derive an upper limit to the gas mass which implies significant depletion of molecular gas in the disk. The mass of this disk and the evolutionary trends observed are similar to those found for intermediate mass Herbig Ae stars and low mass T Tauri stars.Comment: 4 pages, 3 Figures, accepted for publication in ApJ
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