56 research outputs found

    Toward a Consistent Description of the PNC Experiments in A=18-21 Nuclei

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    The experimental PNC results in 18^{18}F, 19^{19}F, 21^{21}Ne and the current theoretical analysis show a discrepancy . If one interprets the small limit of the experimentally extracted PNC matrix element for 21^{21}Ne as a destructive interference between the isoscalar and the isovector contribution, then it is difficult to understand why the isovector contribution in 18^{18}F is so small while the isoscalar + isovector contribution in 19^{19}F is relatively large. In order to understand the origin of this discrepancy a comparison of the calculated PNC matrix elements was performed. It is shown that the 18^{18}F and 21^{21}Ne matrix elements contain important contributions from 3ω\hbar \omega and 4ω\hbar \omega configuration and that the (0+1)ω\hbar \omega calculations give distorted results.Comment: REVTEX, 16 pages, 1 postscriptum figure uuencoded and appende

    Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.

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    Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability

    Staggering of the Nuclear Charge Radii in a Superfluid Model with Good Particle Number

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    A simple superfluid model with an effective four body interaction of monopole pairing type is used to explain the staggering of the charge radii in the isotope chains. The contribution of deformation and of the particle number projection are analyzed for the Sn isotopes. Good results are obtained for the staggering parameters and neutron pairing energies.Comment: RevTex, 19 pages and 4 postscript figures uuencoded and attached. To appear in Phys. Rev.

    Elective cancer surgery in COVID-19-free surgical pathways during the SARS-CoV-2 pandemic: An international, multicenter, comparative cohort study

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    PURPOSE As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19–free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19–free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19–free surgical pathways. Patients who underwent surgery within COVID-19–free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19–free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score–matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19–free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION Within available resources, dedicated COVID-19–free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

    Elective Cancer Surgery in COVID-19-Free Surgical Pathways During the SARS-CoV-2 Pandemic: An International, Multicenter, Comparative Cohort Study.

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    PURPOSE: As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19-free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS: This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19-free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS: Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19-free surgical pathways. Patients who underwent surgery within COVID-19-free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19-free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score-matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19-free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION: Within available resources, dedicated COVID-19-free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

    A case report: Ventriculo-peritoneal Shunt in the Presence of Chylous Ascites—Is It Safe?

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    \ua9 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG. Congenital chylous ascites (CCA) is a rare condition where there is an accumulation of chyle in the peritoneal cavity. Primary CCA due to dysplastic lymphatics is the most common cause in children. CCA discovered on ventriculopertoneal (VP) shunt insertion following previous myelomeningocele repair has only been described in a single paper before with the authors recommending a VP shunt safe to be sited in the presence of CCA. In this paper, we present a case of CCA in a term neonate with a myelomeningocele and an imperforate anus who underwent the siting of a VP shunt with no adverse effect. We provide an alternative hypothesise suggesting the link between raised intra-abdominal pressure caused by the imperforate anus as the aetiological factor in CCA

    Growth and Erosive Wear Properties of MPCVD Diamond Coatings on Sintered Tungsten Carbide Substrates

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    AbstractAdherent diamond coatings up to ∼35 um thick have been grown by microwave plasma CVD (MPCVD) on sintered tungsten carbide (WC) substrates and their erosive wear properties investigated under high velocity air-sand erosion testing. Two different sintered tungsten carbide (WC) substrates have been investigated and compared, the binder being either 6%Co or 5%Ni by weight. Coating properties are sensitive functions of surface pre-treatment and deposition procedures. Adherent coatings offer significantly better erosion resistance compared to uncoated substrates, with the erosion rate being lower by up to a factor between ∼5 and 20 for particle test velocities of 148 ms-1 and 63 ms-1 respectively. Films with low residual stress appear to exhibit longer times to failure which tends to occur catastrophically along the coating-substrate interface.</jats:p
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