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A study of global atmospheric budget and distribution of acetone using global atmospheric model STOCHEM-CRI
No full textThe impact of including a more detailed VOC oxidation scheme (CRI v2-R5) with a multi-generational approach for simulating tropospheric acetone is investigated using a 3-D global model, STOCHEM-CRI. The CRI v2-R5 mechanism contains photochemical production of acetone from monoterpenes which account for 64\% (46.8 Tg/yr) of the global acetone sources in STOCHEM-CRI. Both photolysis and oxidation by OH in the troposphere contributes equally (42\%, each) and dry deposition contributes 16\% of the atmospheric sinks of acetone. The tropospheric life-time and the global burden of acetone are found to be 18 days and 3.5 Tg, respectively, these values being close to those reported in the study of Jacob et al. (2002). A dataset of aircraft campaign measurements are used to evaluate the inclusion of acetone formation from monoterpenes in the CRI v2-R5 mechanism used in STOCHEM-CRI. The overall comparison between measurements and models show that the parameterised approach in STOCHEM-NAM (no acetone formation from monoterpenes) underpredicts the mixing ratios of acetone in the atmosphere. However, using a detailed monoterpene oxidation mechanism forming acetone has brought the STOCHEM-CRI into closer agreement with measurements with an improvement in the vertical simulation of acetone. The annual mean surface distribution of acetone simulated by the STOCHEM-CRI shows a peak over forested regions where there are large biogenic emissions and high levels of photochemical activity. Year-long observations of acetone and methanol at the Mace Head research station in Ireland are compared with the simulated acetone and methanol produced by the STOCHEM-CRI and found to produce good overall agreement between model and measurements. The seasonal variation of model and measured acetone levels at Mace Head, California, New Hampshire and Minnesota show peaks in summer and dips in winter, suggesting that photochemical production may have the strongest effect on its seasonal trend. (C) 2015 The Authors. Published by Elsevier Ltd
The shock index predicts acute mortality outcomes in stroke.
No full textBACKGROUND: Shock index (SI) (ratio between heart rate and systolic blood pressure) has been shown to be associated with poor mortality outcomes in trauma and pneumonia; however it has yet to be examined in stroke. We aimed to examine the relationship between SI and acute outcomes of inpatient, 3-day and 7-day mortality in stroke. Secondly, we aimed to compare SI and systolic blood pressure (SBP) alone in predicting above outcomes. METHODS: Data from a multicentre prospective cohort study conducted between October 2009 and September 2012 in eight NHS trusts in East of England were analysed. The relationships between SI, SBP and study outcomes were assessed using multivariable logistic regression models using mid-quintile groups as the reference category. Receiver operating characteristic (ROC) curves assessed the discriminating ability between the SI and SBP models. RESULTS: A total of 2121 stroke patients were included (47.4% men; mean age 77.10 (sd) 12.40) years. The lowest quintile of the SI, had an increased odds of 3-day and 7-day mortality, adjusted odds ratio (AOR) 2.45 (95% CI:1.16-5.17) and 1.88 (1.01-3.49), respectively. Patients with the highest quintile of SI also had increased odds of in-patient, 3-day and 7-day mortality, AORs 1.85 (1.17-2.92), 2.18 (1.03-4.63) and 2.45 (1.34-4.49), respectively. Similarly, SBP had a U-shape relationship with mortality. All measures had an ROC area under the curve >0.8 but there was no difference in the discriminating ability between SI and SBP. CONCLUSIONS: SI at extremely high and low values appeared to predict stroke mortality and appears to be particularly useful in predicting very early (3-day) mortality
Surface Properties of Nanocrystalline PbS Films Deposited at the Water-Oil Interface: A Study of Atmospheric Aging
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The Inferior Whorl For Detecting Diabetic Peripheral Neuropathy Using Corneal Confocal Microscopy
No full textPurpose: In vivo corneal confocal microscopy (CCM) is increasingly used as a surrogate endpoint in studies of diabetic polyneuropathy (DPN). However, it is not clear whether imaging the central cornea provides optimal diagnostic utility for DPN. Therefore, we compared nerve morphology in the central cornea and the inferior whorl, a more distal and densely innervated area located inferior and nasal to the central cornea.Methods: A total of 53 subjects with type 1/type 2 diabetes and 15 age-matched control subjects underwent detailed assessment of neuropathic symptoms (NPS), deficits (neuropathy disability score [NDS]), quantitative sensory testing (vibration perception threshold [VPT], cold and warm threshold [CT/WT], and cold- and heat-induced pain [CIP/HIP]), and electrophysiology (sural and peroneal nerve conduction velocity [SSNCV/PMNCV], and sural and peroneal nerve amplitude [SSNA/PMNA]) to diagnose patients with (DPN+) and without (DPN−) neuropathy. Corneal nerve fiber density (CNFD) and length (CNFL) in the central cornea, and inferior whorl length (IWL) were quantified.Results: Comparing control subjects to DPN− and DPN+ patients, there was a significant increase in NDS (0 vs. 2.6 ± 2.3 vs. 3.3 ± 2.7, P < 0.01), VPT (V; 5.4 ± 3.0 vs. 10.6 ± 10.3 vs. 17.7 ± 11.8, P < 0.01), WT (°C; 37.7 ± 3.5 vs. 39.1 ± 5.1 vs. 41.7 ± 4.7, P < 0.05), and a significant decrease in SSNCV (m/s; 50.2 ± 5.4 vs. 48.4 ± 5.0 vs. 39.5 ± 10.6, P < 0.05), CNFD (fibers/mm2; 37.8 ± 4.9 vs. 29.7 ± 7.7 vs. 27.1 ± 9.9, P < 0.01), CNFL (mm/mm2; 27.5 ± 3.6 vs. 24.4 ± 7.8 vs. 20.7 ± 7.1, P < 0.01), and IWL (mm/mm2; 35.1 ± 6.5 vs. 26.2 ± 10.5 vs. 23.6 ± 11.4, P < 0.05). For the diagnosis of DPN, CNFD, CNFL, and IWL achieved an area under the curve (AUC) of 0.75, 0.74, and 0.70, respectively, and a combination of IWL-CNFD achieved an AUC of 0.76.Conclusions: The parameters of CNFD, CNFL, and IWL have a comparable ability to diagnose patients with DPN. However, IWL detects an abnormality even in patients without DPN. Combining IWL with CNFD may improve the diagnostic performance of CCM
Patients' perceptions and experiences of venous leg ulceration and their attitudes to larval therapy: an in-depth qualitative study.
No full textBACKGROUND: Venous leg ulcers are a common and distressing condition that can impair quality of life. Larval therapy has been widely promoted for the treatment of different types of chronic wounds, yet little is known about its acceptability to patients. OBJECTIVES: To explore patients' experiences of venous leg ulceration and of the acceptability of larval therapy as a treatment. DESIGN: Qualitative study, using semi-structured interviews alongside a randomized controlled trial. Interview data were transcribed and analysed for thematic content. Data were collected from April 2007 to July 2007. SETTING AND PARTICIPANTS: Eighteen people (12 men, 6 women), aged between 29 and 93 years (median age 64 years), with at least one venous leg ulcer, took part in the study. Fourteen people were recruited from two vascular clinics (one attached to a hospital and the other located in a community setting). A further four people were recruited through referral from a team of community nurses. FINDINGS: Participants portrayed lives blighted by the presence of one or more leg ulcers. The majority were willing to try 'maggots' (larvae) and able to overcome feelings of squeamishness because of their strong desire to heal their ulcers. Five people treated with larvae were included in the study. Initial improvements in the condition of their ulcers were not sustained, and two participants experienced severe pain. DISCUSSION AND CONCLUSIONS: Patients may hold unrealistic expectations that larval therapy will effect a longed-for cure for their leg ulcer(s) but an absence of healing may lead to feelings of disappointment or despair
