4,192 research outputs found

    Integrated support structure

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    This Major Qualifying Project is part of the Advanced Space Design Program at WPI. The goal is to design a support structure for a NASA GetAway Special experimental canister. The payload integration, weight, volume, and structural integrity of the canister as specified by NASA guidelines were studied. The end result is a complete set of design drawings with interface drawings and data to specify the design and leave a base on which the next group can concentrate

    The impact of preoperative dexamethasone on the magnitude of the postoperative systemic inflammatory response and complications following surgery for colorectal cancer

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    Background: The magnitude of the postoperative systemic inflammatory response (SIR), as evidenced by C-reactive protein (CRP), is associated with both short- and long-term outcomes following surgery for colorectal cancer. The present study examined the impact of preoperative dexamethasone on the postoperative SIR and complications following elective surgery for colorectal cancer. Methods: Patients who underwent elective surgery, with curative intent, for colorectal cancer at a single center between 2008 and 2016 were included (n = 556) in this study. Data on the use of preoperative dexamethasone were obtained from anesthetic records, and its impact on CRP on postoperative days (PODs) 3 and 4, as well as postoperative complications, was assessed using propensity score matching (n = 276). Results: In the propensity score-matched cohort, preoperative dexamethasone was associated with fewer patients exceeding the established CRP threshold of 150 mg/L on POD 3 (odds ratio [OR] 0.42, 95% confidence interval [CI] 0.26–0.70, p < 0.001) and fewer postoperative complications (OR 0.53, 95% CI 0.33–0.86, p = 0.009). Similar results for both POD 3 CRP and complications were observed when using propensity score-adjusted regression (OR 0.40, 95% CI 0.28–0.57 and OR 0.57, 95% CI 0.41–0.80, respectively) and propensity score stratification (OR 0.41, 95% CI 0.25–0.57 and OR 0.53, 95% CI 0.33–0.86, respectively). Conclusions: Preoperative dexamethasone was associated with a lower postoperative SIR and fewer complications following elective surgery for colorectal cancer

    The relationship between cardiopulmonary exercise test variables, the systemic inflammatory response, and complications following surgery for colorectal cancer

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    Background: Both preoperative cardiopulmonary exercise test (CPET)-derived measures of fitness and postoperative C-reactive protein (CRP) concentrations are associated with complications following surgery for colorectal cancer. The aim of the present pilot study was to examine the relationship between CPET and postoperative CRP concentrations in this patient group. Methods: Patients who had undergone CPET prior to elective surgery for histologically confirmed colorectal cancer in a single centre between September 2008 and April 2017 were included. Preoperative VO2 at the anaerobic threshold (AT) and peak exercise were recorded, along with preoperative modified Glasgow Prognostic Score (mGPS) and CRP on each postoperative day. Results: Thirty-eight patients were included. The majority were male (30, 79%), over 65 years old (30, 79%), with colonic cancer (23, 61%) and node-negative disease (24, 63%). Fourteen patients (37%) had open surgery and 24 (63%) had a laparoscopic resection. A progressive reduction in VO2 at peak exercise was significantly associated with both increasing American Society of Anesthesiology (ASA) grade (median, ml/kg/min: ASA 1 = 22, ASA 2 = 19, ASA 3 = 15, ASA 4 = 12, p = 0.014) and increasing mGPS (median, ml/kg/min: mGPS 0 = 18, mGPS 1 = 16, mGPS 2 = 14, p = 0.039) There was no significant association between either VO2 at the AT or peak exercise and postoperative CRP. Conclusions: The present pilot study reports a possible association between preoperative CPET-derived measures of exercise tolerance, and the preoperative systemic inflammatory response, but not postoperative CRP in patients undergoing surgery for colorectal cancer

    How and why systemic inflammation worsens quality of life in patients with advanced cancer

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    Introduction: The presence of an innate host systemic inflammatory response has been reported to be a negative prognostic factor in a wide group of solid tumour types in both the operable and advanced setting, both local and distant. In addition, this host systemic inflammatory response is associated with both clinician reported patient performance status and self-reported measures of quality of life in patients with cancer. Areas covered: A variety of mechanisms are thought to underlie this, including the influence of the host immune response on physical symptoms such as pain and fatigue, its effect on organ systems associated with physical ability and well being such as skeletal muscle, and bone marrow. Furthermore, this innate inflammatory response is thought to have a direct negative impact on mood through its action on the central nervous system. Expert commentary: It is clear that the host systemic inflammatory response represents a target for intervention in terms of both improving quality of life and prognosis in patients with advanced cancer. Based on this paradigm, future research should focus both on pathways which might be targeted by novel agents, but also on whether existing anti-inflammatory drugs might be of benefit

    Parton Distributions for Event Generators

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    In this paper, conventional Global QCD analysis is generalized to produce parton distributions optimized for use with event generators at the LHC. This optimization is accomplished by combining the constraints due to existing hard-scattering experimental data with those from anticipated cross sections for key representative SM processes at LHC (by the best available theory) as joint input to the global analyses. The PDFs obtained in these new type of global analyses using matrix elements calculated in any given order will be best suited to work with event generators of that order, for predictions at the LHC. This is most useful for LO event generators at present. Results obtained from a few candidate PDF sets (labeled as CT09MCS, CT09MC1 and CT09MC2) for LO event generators produced in this way are compared with those from other approaches.Comment: 35 pages, 19 figures, and 4 table

    Staging the tumor and staging the host: A two centre, two country comparison of systemic inflammatory responses of patients undergoing resection of primary operable colorectal cancer

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    Background: How systemic inflammation-based prognostic scores such as the modified Glasgow Prognostic Score (mGPS) and neutrophil:lymphocyte ratio (NLR) differ across populations of patients with colorectal cancer (CRC) remains unknown. The present study examined the mGPS and NLR in patients from United Kingdom (UK) and Japan. Methods: Patients undergoing resection of TNM I-III CRC in two centres in the UK and Japan were included. Differences in clinicopathological characteristics and mGPS (0-CRP≤10 mg/L, 1-CRP>10 mg/L, 2-CRP>10 mg/L, albumin<35 g/L) and NLR (≤5/>5) were examined. Results: Patients from UK (n = 581) were more likely to be female, high ASA and BMI, present as an emergency (all P < 0.01) and have higher T stage compared to those from Japan (n = 559). After controlling for differences in tumor and host characteristics, patients from Japan were less likely to be systemically inflamed (OR: mGPS: 0.37, 95%CI 0.27–0.50, P < 0.001; NLR: 0.53, 95%CI 0.35–0.79, P = 0.002). Conclusion: Systemic inflammatory responses differ between populations with colorectal cancer. Given their prognostic value, reporting of systemic inflammation-based scores should be incorporated into future studies reporting patient outcomes. Summary: Although the systemic inflammatory response is recognised as a prognostic factor in patients with colorectal cancer, it is not clear how these may differ between distinct geographical populations. The present study examines differences in the prevalence of elevated systemic inflammatory responses (modified Glasgow Prognostic Score and neutrophil:lymphocyte ratio) between two populations undergoing resection of colorectal cancer in the United Kingdom and Japan

    Reactivity and Sintering Kinetics of Au/TiO2(110) Model Catalysts: Particle Size Effects

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    We review here our studies of the reactivity and sintering kinetics of model catalysts consisting of gold nanoparticles dispersed on TiO2(110). First, the nucleation and growth of vapor-deposited gold on this surface was experimentally examined using x-ray photoelectron spectroscopy and low energy ion scattering. Gold initially grows as two-dimensional islands up to a critical coverage, hcr, after which 3D gold nanoparticles grow. The results at different temperatures are fitted well with a kinetic model, which includes various energetic parameters for Au adatom migration. Oxygen was dosed onto the resulting gold nanoparticles using a hot filament technique. The desorption energy of Oa was examined using temperature programmed desorption (TPD). The Oa is bonded ~40% more strongly to smaller (thinner) Au islands. Gaseous CO reacts rapidly with this Oa to make CO2, probably via adsorbed CO. The reactivity of Oa with CO increases with increasing particle size, as expected based on Brønsted relations. Propene adsorption leads to TPD peaks for three different molecularly adsorbed states on Au/TiO2(110), corresponding to propene adsorbed on gold islands, to Ti sites on the substrate, and to the perimeter of gold islands, with adsorption energies of 40, 52 and 73 kJ/mol, respectively. Thermal sintering of the gold nanoparticles was explored using temperature-programmed low-energy ion scattering. These sintering rates for a range of Au loadings at temperatures from 200 to 700 K were well fitted by a theoretical model which takes into consideration the dramatic effect of particle size on metal chemical potential using a modified bond additivity model. When extrapolated to simulate isothermal sintering at 700 K for 1 year, the resulting particle size distribution becomes very narrow. These results question claims that the shape of particle size distributions reveal their sintering mechanisms. They also suggest why the growth of colloidal nanoparticles in liquid solutions can result in very narrow particle size distributions
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