4,904 research outputs found

    Arms Industry

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    A summary assessment of the dimensions and concentrations of military equipment manufacture primarily in the United States and western Europe and the extent of availability of this equipment to buyers throughout the world. Treaty-based limitations are also listed

    Predicting opportunities to increase utilization of laparoscopy for rectal cancer

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    Background: Despite proven safety and efficacy, rates of laparoscopy for rectal cancer in the US are low. With reports of inferiority with laparoscopy compared to open surgery, and movements to develop accredited centers, investigating utilization and predictors of laparoscopy are warranted. Our goal was to evaluate current utilization and identify factors impacting use of laparoscopic surgery for rectal cancer. Methods: The Premier™ Hospital Database was reviewed for elective inpatient rectal cancer resections (1/1/2010–6/30/2015). Patients were identified by ICD-9-CM diagnosis codes, and then stratified into open or laparoscopic approaches by ICD-9-CM procedure codes or billing charge. Logistic multivariable regression identified variables predictive of laparoscopy. The Cochran–Armitage test assessed trend analysis. The main outcome measures were trends in utilization and factors independently associated with use of laparoscopy. Results: 3336 patients were included—43.8% laparoscopic (n = 1464) and 56.2% open (n = 1872). Use of laparoscopy increased from 37.6 to 55.3% during the study period (p < 0.0001). General surgeons performed the majority of all resections, but colorectal surgeons were more likely to approach rectal cancer laparoscopically (41.31 vs. 36.65%, OR 1.082, 95% CI [0.92, 1.27], p < 0.3363). Higher volume surgeons were more likely to use laparoscopy than low-volume surgeons (OR 3.72, 95% CI [2.64, 5.25], p < 0.0001). Younger patients (OR 1.49, 95% CI [1.03, 2.17], p = 0.036) with minor (OR 2.13, 95% CI [1.45, 3.12], p < 0.0001) or moderate illness severity (OR 1.582, 95% CI [1.08, 2.31], p < 0.0174) were more likely to receive a laparoscopic resection. Teaching hospitals (OR 0.842, 95% CI [0.710, 0.997], p = 0.0463) and hospitals in the Midwest (OR 0.69, 95% CI [0.54, 0.89], p = 0.0044) were less likely to use laparoscopy. Insurance status and hospital size did not impact use. Conclusions: Laparoscopy for rectal cancer steadily increased over the years examined. Patient, provider, and regional variables exist, with hospital status, geographic location, and colorectal specialization impacting the likelihood. However, surgeon volume had the greatest influence. These results emphasize training and surgeon-specific outcomes to increase utilization and quality in appropriate cases

    Dimethyl sulfide production: what is the contribution of the coccolithophores?

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    Surface topography of hydroxyapatite affects ROS17/2.8 cells response

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    Hydroxyapatite (HA) has been used in orthopedic, dental, and maxillofacial surgery as a bone substitute. The aim of this investigation was to study the effect of surface topography produced by the presence of microporosity on cell response, evaluating: cell attachment, cell morphology, cell proliferation, total protein content, and alkaline phosphatase (ALP) activity. HA discs with different percentages of microporosity (< 5%, 15%, and 30%) were confected by means of the combination of uniaxial powder pressing and different sintering conditions. ROS17/2.8 cells were cultured on HA discs. For the evaluation of attachment, cells were cultured for two hours. Cell morphology was evaluated after seven days. After seven and fourteen days, cell proliferation, total protein content, and ALP activity were measured. Data were compared by means of ANOVA and Duncan’s multiple range test, when appropriate. Cell attachment (p = 0.11) and total protein content (p = 0.31) were not affected by surface topography. Proliferation after 7 and 14 days (p = 0.0007 and p = 0.003, respectively), and ALP activity (p = 0.0007) were both significantly decreased by the most irregular surface (HA30). These results suggest that initial cell events were not affected by surface topography, while surfaces with more regular topography, as those present in HA with 15% or less of microporosity, favored intermediary and final events such as cell proliferation and ALP activity

    Turing instabilities in a mathematical model for signaling networks

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    GTPase molecules are important regulators in cells that continuously run through an activation/deactivation and membrane-attachment/membrane-detachment cycle. Activated GTPase is able to localize in parts of the membranes and to induce cell polarity. As feedback loops contribute to the GTPase cycle and as the coupling between membrane-bound and cytoplasmic processes introduces different diffusion coefficients a Turing mechanism is a natural candidate for this symmetry breaking. We formulate a mathematical model that couples a reaction-diffusion system in the inner volume to a reaction-diffusion system on the membrane via a flux condition and an attachment/detachment law at the membrane. We present a reduction to a simpler non-local reaction-diffusion model and perform a stability analysis and numerical simulations for this reduction. Our model in principle does support Turing instabilities but only if the lateral diffusion of inactivated GTPase is much faster than the diffusion of activated GTPase.Comment: 23 pages, 5 figures; The final publication is available at http://www.springerlink.com http://dx.doi.org/10.1007/s00285-011-0495-

    Two Directly Imaged, Wide-orbit Giant Planets around the Young, Solar Analog TYC 8998-760-1

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    Even though tens of directly imaged companions have been discovered in the past decades, the number of directly confirmed multiplanet systems is still small. Dynamical analysis of these systems imposes important constraints on formation mechanisms of these wide-orbit companions. As part of the Young Suns Exoplanet Survey we report the detection of a second planetary-mass companion around the 17 Myr-old, solar-type star TYC 8998-760-1 that is located in the Lower Centaurus Crux subgroup of the Scorpius–Centaurus association. The companion has a projected physical separation of 320 au and several individual photometric measurements from 1.1 to 3.8 microns constrain a companion mass of 6 ± 1 M Jup, which is equivalent to a mass ratio of q = 0.57 ± 0.10% with respect to the primary. With the previously detected 14 ± 3 M Jup companion that is orbiting the primary at 160 au, TYC 8998-760-1 is the first directly imaged multiplanet system that is detected around a young, solar analog. We show that circular orbits are stable, but that mildly eccentric orbits for either/both components (e > 0.1) are chaotic on gigayear timescales, implying in situ formation or a very specific ejection by an unseen third companion. Due to the wide separations of the companions TYC 8998-760-1 is an excellent system for spectroscopic and photometric follow-up with space-based observatories such as the James Webb Space Telescope

    Neuronal circuitry for pain processing in the dorsal horn

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    Neurons in the spinal dorsal horn process sensory information, which is then transmitted to several brain regions, including those responsible for pain perception. The dorsal horn provides numerous potential targets for the development of novel analgesics and is thought to undergo changes that contribute to the exaggerated pain felt after nerve injury and inflammation. Despite its obvious importance, we still know little about the neuronal circuits that process sensory information, mainly because of the heterogeneity of the various neuronal components that make up these circuits. Recent studies have begun to shed light on the neuronal organization and circuitry of this complex region

    Prioritising surveillance for alien organisms transported as stowaways on ships travelling to South Africa

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    The global shipping network facilitates the transportation and introduction of marine and terrestrial organisms to regions where they are not native, and some of these organisms become invasive. South Africa was used as a case study to evaluate the potential for shipping to contribute to the introduction and establishment of marine and terrestrial alien species (i.e. establishment debt) and to assess how this varies across shipping routes and seasons. As a proxy for the number of species introduced (i.e. 'colonisation pressure') shipping movement data were used to determine, for each season, the number of ships that visited South African ports from foreign ports and the number of days travelled between ports. Seasonal marine and terrestrial environmental similarity between South African and foreign ports was then used to estimate the likelihood that introduced species would establish. These data were used to determine the seasonal relative contribution of shipping routes to South Africa's marine and terrestrial establishment debt. Additionally, distribution data were used to identify marine and terrestrial species that are known to be invasive elsewhere and which might be introduced to each South African port through shipping routes that have a high relative contribution to establishment debt. Shipping routes from Asian ports, especially Singapore, have a particularly high relative contribution to South Africa's establishment debt, while among South African ports, Durban has the highest risk of being invaded. There was seasonal variation in the shipping routes that have a high relative contribution to the establishment debt of the South African ports. The presented method provides a simple way to prioritise surveillance effort and our results indicate that, for South Africa, port-specific prevention strategies should be developed, a large portion of the available resources should be allocated to Durban, and seasonal variations and their consequences for prevention strategies should be explored further. (Résumé d'auteur

    A Dynamic Model of Interactions of Ca^(2+), Calmodulin, and Catalytic Subunits of Ca^(2+)/Calmodulin-Dependent Protein Kinase II

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    During the acquisition of memories, influx of Ca^(2+) into the postsynaptic spine through the pores of activated N-methyl-D-aspartate-type glutamate receptors triggers processes that change the strength of excitatory synapses. The pattern of Ca^(2+) influx during the first few seconds of activity is interpreted within the Ca^(2+)-dependent signaling network such that synaptic strength is eventually either potentiated or depressed. Many of the critical signaling enzymes that control synaptic plasticity, including Ca^(2+)/calmodulin-dependent protein kinase II (CaMKII), are regulated by calmodulin, a small protein that can bind up to 4 Ca^(2+) ions. As a first step toward clarifying how the Ca^(2+)-signaling network decides between potentiation or depression, we have created a kinetic model of the interactions of Ca^(2+), calmodulin, and CaMKII that represents our best understanding of the dynamics of these interactions under conditions that resemble those in a postsynaptic spine. We constrained parameters of the model from data in the literature, or from our own measurements, and then predicted time courses of activation and autophosphorylation of CaMKII under a variety of conditions. Simulations showed that species of calmodulin with fewer than four bound Ca^(2+) play a significant role in activation of CaMKII in the physiological regime, supporting the notion that processing ofCa^(2+) signals in a spine involves competition among target enzymes for binding to unsaturated species of CaM in an environment in which the concentration of Ca^(2+) is fluctuating rapidly. Indeed, we showed that dependence of activation on the frequency of Ca^(2+) transients arises from the kinetics of interaction of fluctuating Ca^(2+) with calmodulin/CaMKII complexes. We used parameter sensitivity analysis to identify which parameters will be most beneficial to measure more carefully to improve the accuracy of predictions. This model provides a quantitative base from which to build more complex dynamic models of postsynaptic signal transduction during learning
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