681 research outputs found
Outcomes following oesophagectomy in patients with oesophageal cancer: a secondary analysis of the ICNARC Case Mix Programme Database
Introduction: This report describes the case mix and outcomes of patients with oesophageal cancer admitted to adult critical care units following elective oesophageal surgery in England, Wales and Northern Ireland.
Methods: Admissions to critical care following elective oesophageal surgery for malignancy were identified using data from the Intensive Care National Audit and Research Centre (ICNARC) Case Mix Programme Database. Information on admissions between December 1995 and September 2007 were extracted and the association between in-hospital mortality and patient characteristics on admission to critical care was assessed using multiple logistic regression analysis. The performance of three prognostic models (Simplified Acute Physiology Score (SAPS) II, Acute Physiology and Chronic Health Evaluation (APACHE) II and the ICNARC physiology score) was also evaluated.
Results: Between 1995 and 2007, there were 7227 admissions to 181 critical care units following oesophageal surgery for malignancy. Overall mortality in critical care was 4.4% and in-hospital mortality was 11%, although both declined steadily over time. Eight hundred and seventy-three (12.2%) patients were readmitted to critical care, most commonly for respiratory complications (49%) and surgical complications (25%). Readmitted patients had a critical care unit mortality of 24.7% and in-hospital mortality of 33.9%. Overall in-hospital mortality was associated with patient age, and various physiological measurements on admission to critical care (partial pressure of arterial oxygen (PaO2):fraction of inspired oxygen (FiO2) ratio, lowest arterial pH, mechanical ventilation, serum albumin, urea and creatinine). The three prognostic models evaluated performed poorly in measures of discrimination, calibration and goodness of fit.
Conclusions: Surgery for oesophageal malignancy continues to be associated with significant morbidity and mortality. Age and organ dysfunction in the early postoperative period are associated with an increased risk of death. Postoperative serum albumin is confirmed as an additional prognostic factor. More work is required to determine how this knowledge may improve clinical management
Elastic energy of polyhedral bilayer vesicles
In recent experiments [M. Dubois, B. Dem\'e, T. Gulik-Krzywicki, J.-C.
Dedieu, C. Vautrin, S. D\'esert, E. Perez, and T. Zemb, Nature (London) Vol.
411, 672 (2001)] the spontaneous formation of hollow bilayer vesicles with
polyhedral symmetry has been observed. On the basis of the experimental
phenomenology it was suggested [M. Dubois, V. Lizunov, A. Meister, T.
Gulik-Krzywicki, J. M. Verbavatz, E. Perez, J. Zimmerberg, and T. Zemb, Proc.
Natl. Acad. Sci. U.S.A. Vol. 101, 15082 (2004)] that the mechanism for the
formation of bilayer polyhedra is minimization of elastic bending energy.
Motivated by these experiments, we study the elastic bending energy of
polyhedral bilayer vesicles. In agreement with experiments, and provided that
excess amphiphiles exhibiting spontaneous curvature are present in sufficient
quantity, we find that polyhedral bilayer vesicles can indeed be energetically
favorable compared to spherical bilayer vesicles. Consistent with experimental
observations we also find that the bending energy associated with the vertices
of bilayer polyhedra can be locally reduced through the formation of pores.
However, the stabilization of polyhedral bilayer vesicles over spherical
bilayer vesicles relies crucially on molecular segregation of excess
amphiphiles along the ridges rather than the vertices of bilayer polyhedra.
Furthermore, our analysis implies that, contrary to what has been suggested on
the basis of experiments, the icosahedron does not minimize elastic bending
energy among arbitrary polyhedral shapes and sizes. Instead, we find that, for
large polyhedron sizes, the snub dodecahedron and the snub cube both have lower
total bending energies than the icosahedron
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Effectiveness of a quality improvement collaborative in reducing time to surgery for patients requiring emergency cholecystectomy.
Background:Acute gallstone disease is a high-volume emergency general surgery presentation with wide variations in the quality of care provided across the UK. This controlled cohort evaluation assessed whether participation in a quality improvement collaborative approach reduced time to surgery for patients with acute gallstone disease to fewer than 8 days from presentation, in line with national guidance. Methods:Patients admitted to hospital with acute biliary conditions in England and Wales between 1 April 2014 and 31 December 2017 were identified from Hospital Episode Statistics data. Time series of quarterly activity were produced for the Cholecystectomy Quality Improvement Collaborative (Chole-QuIC) and all other acute National Health Service hospitals (control group). A negative binomial regression model was used to compare the proportion of patients having surgery within 8 days in the baseline and intervention periods. Results:Of 13 sites invited to join Chole-QuIC, 12 participated throughout the collaborative, which ran from October 2016 to January 2018. Of 7944 admissions, 1160 patients had a cholecystectomy within 8 days of admission, a significant improvement (P < 0·050) from baseline performance. This represented a relative change of 1·56 (95 per cent c.i. 1·38 to 1·75), compared with 1·08 for the control group. At the individual site level, eight of the 12 Chole-QuIC sites showed a significant improvement (P < 0·050), with four sites increasing their 8-day surgery rate to over 20 per cent of all emergency admissions, well above the mean of 15·3 per cent for control hospitals. Conclusion:A surgeon-led quality improvement collaborative approach improved care for patients requiring emergency cholecystectomy
Offenders' Crime Narratives across Different Types of Crimes
The current study explores the roles offenders see themselves playing during an offence and their relationship to different crime types. One hundred and twenty incarcerated offenders indicated the narrative roles they acted out whilst committing a specific crime they remembered well. The data were subjected to Smallest Space Analysis (SSA) and four
themes were identified: Hero, Professional, Revenger and Victim in line with the recent theoretical framework posited for Narrative Offence Roles (Youngs & Canter, 2012). Further analysis showed that different subsets of crimes were more like to be associated with different narrative offence roles. Hero and Professional were found to be associated with property offences (theft, burglary and shoplifting), drug offences and robbery and Revenger
and Victim were found to be associated with violence, sexual offences and murder. The theoretical implications for understanding crime on the basis of offenders' narrative roles as well as practical implications are discussed
Bonding in Functionalized Aziridines: Nitrogen-15 and Carbon-13 Studies
Two isomeric pairs of cis- and trans-1-cyclohexyl-2-phenyl-3-benzoylaziridines
have been synthesized: (1) with a nitrogen-15 labelled nitrogen, and (2) with carbon-13
labelled ring carbons. The carbon-13 to X (where X=nitrogen-15, carbon-13 or
hydrogen-I) spin-spin coupling constants were measured and interpreted in terms
of stereoelectronic effects. X-ray crystallographic data (earlier determined for cisand
trans-1-cyclohexyl-2-phenyl-3-(p-toluyl)aziridines)1 appear in good agreement
with the NMR data. Bonding is discussed for the three-ring itself (NMR studies)
and for its substituents (X-ray studies). It is concluded that stereochemical interaction
of the Van der Waals type is an important determinant of aziridine bond
length. Three-ring to carbonyl hyperconjugation is correlated with stereoelectronic
interactions in the trans isomer
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PAUSED for thought? Using verbal protocol analysis to understand the situational and temporal cues in the decision-making of residential burglars
Using verbal protocol analysis (VPA) alongside semi-structured interviews, this research aimed to explicate the situational dynamics that inform the decision-making and target selection of residential burglars. Focusing on the VPA method, novel to criminological research, the paper considers the contribution of this empirical approach for studying the decision-making of offenders in situ. The findings reveal a series of cues, encapsulated in the ‘PAUSED’ model, that are drawn upon by residential burglars to assess the suitability of a target; determining whether it is profitable, accessible, uninterruptible, surveillable, escapable and/or dishonourable. The PAUSED model is unpacked to articulate a collection of visual stimuli that serve to disrupt and suspend the otherwise rapid flow of target appraisal. Discussion of the strengths and limitations of the VPA method, and how it can compliment other approaches to understanding the decision-making of residential burglars, is provided
Fullerene‐like structures of Cretaceous crinoids reveal topologically limited skeletal possibilities
There are few cases where numbers or types of possible phenotypes are known, although vast state spaces have been postulated. Rarely applied in this context, graph theory and topology enable enumeration of possible phenotypes and evolutionary transitions. Here, we generate polyhedral calyx graphs for the Late Cretaceous, stemless crinoids Marsupites testudinarius and Uintacrinus socialis (Uintacrinoidea Zittel) revealing structural similarities to carbon fullerene and fulleroid molecules (respectively). The U. socialis calyx incorporates numerous plates (e.g. graph vertices |V| ≥ 197), which are small, light, low‐density and have four to eight sides. Therefore, the corresponding number of possible plate arrangements (number of polyhedral graphs) is large (≫1 × 1014). Graph vertices representing plates with sides >6 introduce negative Gaussian curvature (surface saddle points) and topological instability, increasing buckling risk. However, observed numbers of vertices for Uintacrinus do not allow more stable pentaradial configurations. In contrast, the Marsupites calyx dual graph has 17 faces that are pentagonal or hexagonal. Therefore, it is structurally identical to a carbon fullerene, specifically C30‐D5h. Corresponding graph restrictions result in constraint to only three structural options (fullerene structures C30‐C2v 1, C30‐C2v 2 and C30‐D5h). Further restriction to pentaradial symmetry allows only one possibility: the Marsupites phenotype. This robust, stable topology is consistent with adaptation to predation pressures of the Mesozoic marine revolution. Consequently, the most plausible evolutionary pathway between unitacrinoid phenotypes was a mixed heterochronic trade‐off to fewer, larger calyx plates. Therefore, topological limitations radically constrained uintacrinoid skeletal possibilities but thereby aided evolution of a novel adaptive phenotype
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