Kinetics of the Gas Phase Reaction of the Criegee Intermediate CH₂OO with SO₂ as a Function of Temperature

The kinetics of the gas phase reaction of the Criegee intermediate CH2OO with SO2 have been studied as a function of temperature in the range 223–344 K at 85 Torr using flash photolysis of CH2I2/O2/SO2/N2 mixtures at 248 nm coupled to time-resolved broadband UV absorption spectroscopy. Measurements were performed under pseudo-first-order conditions with respect to SO2, revealing a negative temperature dependence. Analysis of experimental results using the Master Equation Solver for Multi-Energy well Reactions (MESMER) indicates that the observed temperature dependence, combined with the reported lack of a pressure dependence in the range 1.5–760 Torr, can be described by a reaction mechanism consisting of the formation of a pre-reaction complex leading to a cyclic secondary ozonide which subsequently decomposes to produce HCHO + SO3. The temperature dependence can be characterised by kCH2OO+SO2 = (3.72 ± 0.13) × 10-11 (T/298)(-2.05 ± 0.38) cm3 molecule-1 s-1. The observed negative temperature dependence for the title reaction in conjunction with the decrease in water dimer (the main competitor for the Criegee intermediate) concentration at lower temperatures means that Criegee intermediate chemistry can play an enhanced role in SO2 oxidation in the atmosphere at lower temperatures

Gun-shot injuries in UK military casualties - Features associated with wound severity

Introduction: Surgical treatment of high-energy gun-shot wounds (GSWs) to the extremities is challenging. Recent surgical doctrine states that wound tracts from high-energy GSWs should be laid open, however the experience from previous conflicts suggests that some of these injuries can be managed more conservatively. The aim of this study is to firstly characterise the GSW injuries sustained by UK forces, and secondly test the hypothesis that the likely severity of GSWs can be predicted by features of the wound.Methods: The UK Military trauma registry was searched for cases injured by GSW in the five years between 01 January 2009 and 31 December 2013: only UK personnel were included. Clinical notes and radiographs were then reviewed. Features associated with energy transfer in extremity wounds in survivors were further examined with number of wound debridements used as a surrogate marker of wound severity.Results: There were 450 cases who met the inclusion criteria. 96 (21%) were fatally injured, with 354 (79%) surviving their injuries. Casualties in the fatality group had a median New Injury Severity Score (NISS) of 75 (IQR 75-75), while the median NISS of the survivors was 12 (IQR 4-48) with 10 survivors having a NISS of 75. In survivors the limbs were most commonly injured (56%). 'Through and through' wounds, where the bullet passes intact through the body, were strongly associated with less requirement for debridement (p < 0.0001). When a bullet fragmented there was a significant association with a requirement for a greater number of wound debridements (p = 0.0002), as there was if a bullet fractured a bone (p = 0.0006).Conclusions: More complex wounds, as indicated by the requirement for repeated debridements, are associated with injuries where the bullet does not pass straight through the body, or where a bone is fractured. Gunshot wounds should be assessed according to the likely energy transferred, extremity wounds without features of high energy transfer do not require extensive exploration. Crown Copyright (C) 2016 Published by Elsevier Ltd. All rights reserved

Shaping the military wound: issues surrounding the reconstruction of injured servicemen at the Royal Centre for Defence Medicine

The conflict in Afghanistan has produced injuries similar to those produced from military conflicts for generations. What distinguishes the modern casualty of the conflict in Afghanistan from those of other conflicts is the effectiveness of modern field medical care that has led to individuals surviving with injuries, which would have been immediately fatal even a few years ago. These patients present several challenges to the reconstructive surgeon. These injured individuals present early challenges of massive soft-tissue trauma, unstable physiology, complex bony and soft-tissue defects, unusual infections, limited reconstructive donor sites, peripheral nerve injuries and traumatic amputations. Late challenges to rehabilitation include the development of heterotopic ossification in amputation stumps. This paper outlines the approach taken by the reconstructive team at the Royal Centre for Defence Medicine in managing these most difficult of reconstructive challenges

Medium-term outcomes following limb salvage for severe open tibia fracture are similar to trans-tibial amputation

Extremity injuries define the surgical burden of recent conflicts. Current literature is inconclusive when assessing the merits of limb salvage over amputation. The aim of this study was to determine medium term functional outcomes in military casualties undergoing limb salvage for severe open tibia fractures, and compare them to equivalent outcomes for unilateral trans-tibial amputees.Cases of severe open diaphyseal tibia fractures sustained in combat between 2006 and 2010, as described in a previously published series, were contacted. Consenting individuals conducted a brief telephone interview and were asked to complete a SF-36 questionnaire. These results were compared to a similar cohort of 18 military patients who sustained a unilateral trans-tibial amputation between 2004 and 2010.Forty-nine patients with 57 severe open tibia fractures met the inclusion criteria. Telephone follow-up and SF-36 questionnaire data was available for 30 patients (61%). The median follow-up was 4 years (49 months, IQR 39-63). Ten of the 30 patients required revision surgery, three of which involved conversion from initial fixation to a circular frame for non-or mal-union. Twenty-two of the 30 patients (73%) recovered sufficiently to complete an age-standardised basic military fitness test.The median physical component score of SF-36 in the limb salvage group was 46 (IQR 35-54) which was similar to the trans-tibial amputation cohort (p = 0.3057, Mann-Whitney). Similarly there was no difference in mental component scores between the limb salvage and amputation groups (p = 0.1595, Mann-Whitney). There was no significant difference in the proportion of patients in either the amputation or limb salvage group reporting pain (p = 0.1157, Fisher's exact test) or with respect to SF-36 physical pain scores (p = 0.5258, Mann-Whitney).This study demonstrates that medium term outcomes for military patients are similar following trans-tibial amputation or limb salvage following combat trauma. Crown Copyright (C) 2014 Published by Elsevier Ltd. All rights reserved

Medium-term outcomes following limb salvage for severe open tibia fracture are similar to trans-tibial amputation

Extremity injuries define the surgical burden of recent conflicts. Current literature is inconclusive when assessing the merits of limb salvage over amputation. The aim of this study was to determine medium term functional outcomes in military casualties undergoing limb salvage for severe open tibia fractures, and compare them to equivalent outcomes for unilateral trans-tibial amputees. Cases of severe open diaphyseal tibia fractures sustained in combat between 2006 and 2010, as described in a previously published series, were contacted. Consenting individuals conducted a brief telephone interview and were asked to complete a SF-36 questionnaire. These results were compared to a similar cohort of 18 military patients who sustained a unilateral trans-tibial amputation between 2004 and 2010. Forty-nine patients with 57 severe open tibia fractures met the inclusion criteria. Telephone follow-up and SF-36 questionnaire data was available for 30 patients (61%). The median follow-up was 4 years (49 months, IQR 39-63). Ten of the 30 patients required revision surgery, three of which involved conversion from initial fixation to a circular frame for non- or mal-union. Twenty-two of the 30 patients (73%) recovered sufficiently to complete an age-standardised basic military fitness test. The median physical component score of SF-36 in the limb salvage group was 46 (IQR 35-54) which was similar to the trans-tibial amputation cohort (p = 0.3057, Mann-Whitney). Similarly there was no difference in mental component scores between the limb salvage and amputation groups (p = 0.1595, Mann-Whitney). There was no significant difference in the proportion of patients in either the amputation or limb salvage group reporting pain (p = 0.1157, Fisher's exact test) or with respect to SF-36 physical pain scores (p = 0.5258, Mann-Whitney). This study demonstrates that medium term outcomes for military patients are similar following trans-tibial amputation or limb salvage following combat trauma.</p