Electrochemical Detection of Reactive Oxygen Species via a Platinum Microelectrode Array

Oxidative stress, an excess of endogenous or exogenous reactive oxygen species (ROS) in the body, is closely aligned with inflammatory responses. ROS such as hydrogen peroxide, superoxide, and radical hydroxyl ion serve essential functions in fighting infection, but chronic elevation of these species irreversibly damages cellular components. Given the central role of inflammation in a variety of diseases, including Alzheimer’s Disease, atherosclerosis, and rheumatoid arthritis, a low-cost, extracellular, non-invasive assay of ROS is needed. This work reports the use of a platinum microelectrode array (Pt MEA)-based ceramic probe to detect time- and concentration-dependent variations in hydrogen peroxide (H2O2) production by activated macrophages. RAW 264.7 cells were placed under oxidative stress by activation with lipopolysaccharides (LPS). Chronoamperometry was then employed to detect the quantity of H2O2 released by cells at various time intervals up to 48 hours. The most stimulatory concentration of LPS was first identified. Further experiments assessed the anti-inflammatory effect of dexamethasone (Dex), a commonly prescribed steroid medication. As expected, the probe detected significantly increased H2O2 production by LPS-doped macrophages. This pro-inflammatory effect was diminished, but not resolved, in LPS-doped cells treated with Dex. The long-term goal of this research is the development of a non-invasive, robust, multiplexed, point-of-care test of ROS and inflammation. Given the robustness of the materials and the ease of modifying additional microelectrodes within the same probe, these results indicate that the probe is a suitable candidate for further study

OA031-02. Regulatory T cells inhibit CD8 T cell proliferation in HIV-1 infection through CD39/adenosine pathway

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Copyright Education: A Study of the Impact of Formal Copyright Training for Special Librarians

This paper describes a study conducted to examine copyright knowledge among special librarians in the United States to determine factors that may promote an increased knowledge of copyright and how it operates in a particular setting. A review of the literature indicates that awareness of copyright is high, but actual knowledge of copyright is lacking. Little research has been done specifically on the special librarian population, but the literature suggests the importance of the librarian as a facilitator of copyright compliance, and demonstrates a need for copyright education. This study used an online survey to solicit the opinions of special librarians on the issue, garnering 122 usable responses. Results indicate that more than half of the librarians surveyed were not comfortable with their copyright knowledge and showed a positive correlation between comfort and training. Results may be of interest to copyright educators, library managers, librarians, and those assessing MLS curricula

Do we understand the incompressibility of neutron-rich matter?

The ``breathing mode'' of neutron-rich nuclei is our window into the incompressibility of neutron-rich matter. After much confusion on the interpretation of the experimental data, consistency was finally reached between different models that predicted both the distribution of isoscalar monopole strength in finite nuclei and the compression modulus of infinite matter. However, a very recent experiment on the Tin isotopes at the Research Center for Nuclear Physics(RCNP) in Japan has again muddled the waters. Self-consistent models that were successful in reproducing the energy of the giant monopole resonance (GMR) in nuclei with various nucleon asymmetries (such as 90Zr, 144Sm, and 208Pb) overestimate the GMR energies in the Tin isotopes. As important, the discrepancy between theory and experiment appears to grow with neutron excess. This is particularly problematic as models artificially tuned to reproduce the rapid softening of the GMR in the Tin isotopes become inconsistent with the behavior of dilute neutron matter. Thus, we regard the question of ``why is Tin so soft?'' as an important open problem in nuclear structure.Comment: 12 pages, 3 figures, and 1 table. Submitted to the "Focus issue on Open Problems in Nuclear Structure", Journal of Physics

Nonuniform Neutron-Rich Matter and Coherent Neutrino Scattering

Nonuniform neutron-rich matter present in both core-collapse supernovae and neutron-star crusts is described in terms of a semiclassical model that reproduces nuclear-matter properties and includes long-range Coulomb interactions. The neutron-neutron correlation function and the corresponding static structure factor are calculated from molecular dynamics simulations involving 40,000 to 100,000 nucleons. The static structure factor describes coherent neutrino scattering which is expected to dominate the neutrino opacity. At low momentum transfers the static structure factor is found to be small because of ion screening. In contrast, at intermediate momentum transfers the static structure factor displays a large peak due to coherent scattering from all the neutrons in a cluster. This peak moves to higher momentum transfers and decreases in amplitude as the density increases. A large static structure factor at zero momentum transfer, indicative of large density fluctuations during a first-order phase transition, may increase the neutrino opacity. However, no evidence of such an increase has been found. Therefore, it is unlikely that the system undergoes a simple first-order phase transition. It is found that corrections to the commonly used single heavy nucleus approximation first appear at a density of the order of $10^{13}$ g/cm$^3$ and increase rapidly with increasing density. Thus, neutrino opacities are overestimated in the single heavy nucleus approximation relative to the complete molecular dynamics simulations.Comment: 17 pages, 23 included ps figure

When Military Fitness Standards No Longer Apply: The High Prevalence of Metabolic Syndrome in Recent Air Force Retirees

BACKGROUND: Metabolic syndrome (MetS) is strongly associated with cardiovascular disease. With MetS prevalence rates increasing in the U.S. population, prevention efforts have largely focused on diet and exercise interventions. Before retirement, military service members have met fitness requirements for at least 20 years, and have lower MetS rates compared to age-matched U.S. population controls (23.4% vs. 39.0%), which suggests a protective effect of the lifestyle associated with military service. However, MetS rates in military retirees have not been previously reported, so it is unknown whether this protective effect extends beyond military service. The purpose of this study was to examine the prevalence of MetS and individual diagnostic criteria in a population of recent U.S. Air Force (USAF) retirees. METHODS: We obtained institutional review board approval for all participating sites at Wilford Hall Ambulatory Surgical Center. From December 2011 to May 2013, USAF retirees within 8 years of their date of retirement were recruited at five USAF bases. Consenting subjects underwent examination and laboratory studies to assess the five diagnostic criteria measures for MetS. We used binary logistic regression to examine the relationship between various factors and the presence of MetS. RESULTS: The study population (n = 381) was primarily male (81.9%), enlisted (71.1%) and had a mean age of 48.2 years. When applying the American Heart Association MetS diagnostic criteria to this population, the MetS prevalence was 37.2%. When using alternative diagnostic criteria found in other published studies that did not include the use of cholesterol medications, the MetS prevalence was 33.6%. Per American Heart Association criteria, the prevalence of each of the MetS diagnostic criteria was as follows: central obesity, 39.8%; elevated fasting glucose, 32.4%; high blood pressure, 56.8%; low-high-density lipoproteins cholesterol, 33.3%; and elevated triglycerides, 42.7%. MetS was more common among males (odds ratio [OR] = 4.05; confidence interval [CI] = 1.94, 8.48) and enlisted (OR = 2.23; CI = 1.24, 4.01). It was also strongly associated with a history of participating in the Air Force Weight Management Program (OR = 2.82; CI = 1.41, 5.63) and increased weight since retirement (OR = 4.00; CI = 1.84, 8.70). However, the study did not find an association between the presence of MetS and time since retirement or self-reported diet and exercise changes since retirement. CONCLUSIONS: The MetS prevalence among recent USAF retirees represents a shift from age-matched active duty rates toward higher rates described in the overall U.S. POPULATION: This finding suggests the protective health effects of fitness standards may be reduced shortly after retirement. This is true despite activities such as screening before and during military service and exposure to USAF health promotion efforts and fitness standards throughout a period of active duty service lasting at least 20 years. In general, military members should be counseled that on retirement, efforts to maintain a healthy weight have continued benefit and should not be forgotten. The risk of MetS after retirement is particularly increased for those identified as being overweight during their active duty careers. Interventions that prevent and reduce unhealthy weight gain may be an appropriate investment of resources and should be studied further

GSK3-mediated raptor phosphorylation supports amino acid-dependent Q2 mTORC1-directed signalling

The mammalian or mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) is a ubiquitously expressed multimeric protein kinase complex that integrates nutrient and growth factor signals for the co-ordinated regulation of cellular metabolism and cell growth. Herein, we demonstrate that suppressing the cellular activity of glycogen synthase kinase-3 (GSK3), by use of pharmacological inhibitors or shRNA-mediated gene silencing, results in substantial reduction in amino acid (AA)-regulated mTORC1-directed signalling, as assessed by phosphorylation of multiple downstream mTORC1 targets. We show that GSK3 regulates mTORC1 activity through its ability to phosphorylate the mTOR-associated scaffold protein raptor (regulatory-associated protein of mTOR) on Ser(859). We further demonstrate that either GSK3 inhibition or expression of a S859A mutated raptor leads to reduced interaction between mTOR and raptor and under these circumstances, irrespective of AA availability, there is a consequential loss in phosphorylation of mTOR substrates, such as p70S6K1 (ribosomal S6 kinase 1) and uncoordinated-51-like kinase (ULK1), which results in increased autophagic flux and reduced cellular proliferation