The Cholecystectomy As A Day Case (CAAD) Score: A Validated Score of Preoperative Predictors of Successful Day-Case Cholecystectomy Using the CholeS Data Set

Background Day-case surgery is associated with significant patient and cost benefits. However, only 43% of cholecystectomy patients are discharged home the same day. One hypothesis is day-case cholecystectomy rates, defined as patients discharged the same day as their operation, may be improved by better assessment of patients using standard preoperative variables. Methods Data were extracted from a prospectively collected data set of cholecystectomy patients from 166 UK and Irish hospitals (CholeS). Cholecystectomies performed as elective procedures were divided into main (75%) and validation (25%) data sets. Preoperative predictors were identified, and a risk score of failed day case was devised using multivariate logistic regression. Receiver operating curve analysis was used to validate the score in the validation data set. Results Of the 7426 elective cholecystectomies performed, 49% of these were discharged home the same day. Same-day discharge following cholecystectomy was less likely with older patients (OR 0.18, 95% CI 0.15–0.23), higher ASA scores (OR 0.19, 95% CI 0.15–0.23), complicated cholelithiasis (OR 0.38, 95% CI 0.31 to 0.48), male gender (OR 0.66, 95% CI 0.58–0.74), previous acute gallstone-related admissions (OR 0.54, 95% CI 0.48–0.60) and preoperative endoscopic intervention (OR 0.40, 95% CI 0.34–0.47). The CAAD score was developed using these variables. When applied to the validation subgroup, a CAAD score of ≤5 was associated with 80.8% successful day-case cholecystectomy compared with 19.2% associated with a CAAD score >5 (p < 0.001). Conclusions The CAAD score which utilises data readily available from clinic letters and electronic sources can predict same-day discharges following cholecystectomy

Synthesis and properties of complexes of vanadium(V) oxide trichloride with nitrogen- and oxygen-donor ligands

Intensely coloured, extremely moisture sensitive complexes [VOCl3(L)] (L = pyridine, quinoline, Ph3PO, Ph3AsO, pyridine N-oxide), [VOCl3(L)(2)] (L=pyridine, Me3PO, pyridine N-oxide), [VOCl3(L-L)] [L-L = 2,2'-bipyridyl, 1,10-phenanthroline, Ph2P(O)CH2P(O)Ph-2, MeOCH2CH2OMe, 15-crown-5 or Me2NCH2CH2NMe2] and [Cl3OV(mu-L-L)VOCl3] [L-L=18crown-6 or Ph2P(O)CH2P(O)Ph-2] have been prepared from VOCl3 and the appropriate ligands in dichloromethane solution. These constitute the first extended series of complexes of vanadium(V) with neutral donor ligands. They have been fully characterised by analysis, IR, UV/Visible and multinuclear (H-1, P-31, V-51) NMR spectroscopy, and their solution behaviour probed as a function of temperature using 51V NMR spectroscopy. Reducing ligands including phosphanes, arsanes, thio- and selenoethers immediately reduce VOC13 to give V-IV or V-III species. Oxygen atom transfer reactions of some of the complexes with Ph3P, Ph3As, Me2Se and Bu2S, leading to the corresponding ligand oxides are also described

Zn, Fe and S isotope fractionation in a large hydrothermal system

The genesis of hydrothermal ore deposits is of crucial economic importance. This study investigates the extent, causes and consequences of zinc and iron isotope fractionation in a large hydrothermal system at the world-class Navan Zn–Pb orebody, Ireland. Large variations in Zn, Fe and S isotope compositions have been measured in microdrilled sphalerite (ZnS) at the millimetre scale. d66Zn and d56Fe display a well-defined positive correlation and both also correlate with d34S. These relationships represent the combined effects of kinetic Zn and Fe isotope fractionation during sphalerite precipitation, and S isotope variation through mixing of hot, metal-rich hydrothermal fluids and cool, bacteriogenic sulfide-bearing brines. Combined with S isotope data, d56Fe and d66Zn data on mine concentrates confirm that hydrothermal sulfide is a minor component of the overall deposit signature. Our data suggest that incoming pulses of metal-rich hydrothermal fluid triggered sulfide mineralisation, and that rapid precipitation of sphalerite from hydrothermal fluids will lead to strong kinetic fractionation of Zn and Fe isotopes at very short time and length scales, thereby limiting the use of Fe and Zn isotopes as exploration tools within deposits, but revealing the possibility of detecting new deposits from isotopically heavy Zn–Fe geochemical halos.Science Foundation IrelandDG 16/10/201

A neural mass model of spectral responses in electrophysiology

We present a neural mass model of steady-state membrane potentials measured with local field potentials or electroencephalography in the frequency domain. This model is an extended version of previous dynamic causal models for investigating event-related potentials in the time-domain. In this paper, we augment the previous formulation with parameters that mediate spike-rate adaptation and recurrent intrinsic inhibitory connections. We then use linear systems analysis to show how the model's spectral response changes with its neurophysiological parameters. We demonstrate that much of the interesting behaviour depends on the non-linearity which couples mean membrane potential to mean spiking rate. This non-linearity is analogous, at the population level, to the firing rate–input curves often used to characterize single-cell responses. This function depends on the model's gain and adaptation currents which, neurobiologically, are influenced by the activity of modulatory neurotransmitters. The key contribution of this paper is to show how neuromodulatory effects can be modelled by adding adaptation currents to a simple phenomenological model of EEG. Critically, we show that these effects are expressed in a systematic way in the spectral density of EEG recordings. Inversion of the model, given such non-invasive recordings, should allow one to quantify pharmacologically induced changes in adaptation currents. In short, this work establishes a forward or generative model of electrophysiological recordings for psychopharmacological studies