49 research outputs found

    Overview of the techniques used for the study of non-terrestrial bodies: Proposition of novel non-destructive methodology

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    Meteorites and impact glasses have been largely analysed using different techniques, but most studies have been focused on their geologicalemineralogical characterization and isotopic ratios, mainly of a destructive nature. However, much more information can be gained by applying novel non-destructive analytical procedures and techniques that have been scarcely used to analyse these materials. This overview presents some new methodologies to study these materials and compares these new approaches with the commonly used ones. Techniques such as X-Ray Fluorescence (XRF) and Laser Induced Breakdown Spectroscopy (LIBS), for elemental characterization, the hyphenated Raman spectroscopy- SEM/EDS and the combination of them, allow extracting simultaneous information from elemental, molecular and structural data of the studied sample; furthermore, the spectroscopic image capabilities of such techniques allow a better understanding of the mineralogical distribution. © 2017 Elsevier B.V. All rights reserved.Ministerio de Economía, Industria y Competitividad (project ESP2014-56138-C3-2-R

    Automated Detection of External Ventricular and Lumbar Drain-Related Meningitis Using Laboratory and Microbiology Results and Medication Data

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    OBJECTIVE: Monitoring of healthcare-associated infection rates is important for infection control and hospital benchmarking. However, manual surveillance is time-consuming and susceptible to error. The aim was, therefore, to develop a prediction model to retrospectively detect drain-related meningitis (DRM), a frequently occurring nosocomial infection, using routinely collected data from a clinical data warehouse. METHODS: As part of the hospital infection control program, all patients receiving an external ventricular (EVD) or lumbar drain (ELD) (2004 to 2009; n = 742) had been evaluated for the development of DRM through chart review and standardized diagnostic criteria by infection control staff; this was the reference standard. Children, patients dying <24 hours after drain insertion or with <1 day follow-up and patients with infection at the time of insertion or multiple simultaneous drains were excluded. Logistic regression was used to develop a model predicting the occurrence of DRM. Missing data were imputed using multiple imputation. Bootstrapping was applied to increase generalizability. RESULTS: 537 patients remained after application of exclusion criteria, of which 82 developed DRM (13.5/1000 days at risk). The automated model to detect DRM included the number of drains placed, drain type, blood leukocyte count, C-reactive protein, cerebrospinal fluid leukocyte count and culture result, number of antibiotics started during admission, and empiric antibiotic therapy. Discriminatory power of this model was excellent (area under the ROC curve 0.97). The model achieved 98.8% sensitivity (95% CI 88.0% to 99.9%) and specificity of 87.9% (84.6% to 90.8%). Positive and negative predictive values were 56.9% (50.8% to 67.9%) and 99.9% (98.6% to 99.9%), respectively. Predicted yearly infection rates concurred with observed infection rates. CONCLUSION: A prediction model based on multi-source data stored in a clinical data warehouse could accurately quantify rates of DRM. Automated detection using this statistical approach is feasible and could be applied to other nosocomial infections

    Integrating Plant Essential Oils and Kaolin for the Sustainable Management of Thrips and Tomato Spotted Wilt on Tomato

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    Thrips-vectored Tomato spotted wilt virus is one of the most devastating pest complexes affecting tomato in the southern United States and elsewhere. Field trials were conducted over 2 years to determine the effects of volatile plant essential oils and kaolin-based particle films on the incidence of tomato spotted wilt and population dynamics of Frankliniella spp. thrips. The essential oils, geraniol (a monoterpene constituent of various plant essential oils), lemongrass (Cymbopogon flexuosus) oil, and tea tree (Melaleuca alternifolii) oil, were compared with a standard insecticide treatment and an untreated control. All treatments were applied with and without kaolin, in a 5 × 2 factorial design. Although the treatments did not clearly affect the abundance of vector species, there were treatment differences in the incidence of tomato spotted wilt. When combined with kaolin, the three essential oils reduced tomato spotted wilt incidence by 32 to 51% in 2005 and by 6 to 25% in 2006 compared with the control. In both years, tea tree oil plus kaolin reduced tomato spotted wilt as well as the standard insecticide treatments. Overall, kaolin significantly increased yield by over 26% compared to treatments without kaolin. When applied with kaolin, the three essential oils produced yields similar to the insecticide standard. Therefore, naturally occurring products, such as essential oils and kaolin, could be used successfully to reduce insecticide use on tomatoes

    Surgical instrument tracking optimizes trans-sphenoidal endoscopic treatment of petrous apex cholesterol granuloma

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    During endoscopic trans-sphenoidal treatment of petrous apex cholesterol granuloma, the challenge for the surgeon is to drill the posterior wall of the sphenoid sinus to reach the lesion while attempting to avoid the internal carotid artery (ICA). A refined neuronavigation technique is presented that diminishes bonework needed for exposure and marsupialization, and simultaneously minimizes risks of accidental harm to the ICA. The technique utilizes real-time intraoperative instrument tracking of a drill, enabling safe creation of a direct canal toward the cyst just medial to the paraclival ICA and of a curette for entirely image-guided marsupialization of the cyst's deep areas through the canal

    Dynamics of cerebral tissue injury and perfusion after temporary hypoxia-ischemia in the rat : evidence for region-specific sensitivity and delayed damage

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    Background and Purpose: Selective regional sensitivity and delayed damage in cerebral ischemia provide opportunities for directed and late therapy for stroke. Our aim was to characterize the spatial and temporal profile of ischemia-induced changes in cerebral perfusion and tissue status, with the use of noninvasive MRI techniques, to gain more insight in region-specific vulnerability and delayed damage. Methods: Rats underwent 20 minutes of unilateral cerebral hypoxia-ischemia (HI). We performed combined repetitive quantitative diffusion-weighted, T2-weighted, and dynamic susceptibility contrast-enhanced MRI from before HI to 5 hours after HI. Data were correlated with parallel blood oxygenation level-dependent MRI and laser-Doppler flowmetry. Finally, MRI and histology were done 24 and 72 hours after HI. Results: Severe hypoperfusion during HI caused acute reductions of the apparent diffusion coefficient (ADC) of tissue water in the ipsilateral hemisphere. Reperfusion resulted in dynamic perfusion alterations that varied spatially. The ADC recovered completely within 1 hour in the hippocampus (from 0.68 +/- 0.07 to 0.83 +/- 0.09x10 sup -3 mm2/s), cortex (from 0.56 +/- 0.06 to 0.77 +/- 0.07x10 sup -3 mm2/s), and caudate putamen (from 0.58 +/- 0.06 to 0.75 +/- 0.06x10 sup -3 mm2/s) but only partially or not at all in the thalamus (from 0.65 +/- 0.07 to 0.68 +/- 0.12x10 sup -3 mm2/s) and substantia nigra (from 0.80 +/- 0.08 to 0.76 +/- 0.10x10 sup -3 mm2/s). Secondary ADC reductions, accompanied by significant T2 elevations and histological damage, were observed after 24 hours. Initial and secondary ADC decreases were observed invariably in the hippocampus, cortex, and caudate putamen and in approximately 70% of the animals in the thalamus and substantia nigra. Conclusions: Region-specific responses and delayed ischemic damage after transient HI were demonstrated by MRI. Acute reperfusion-induced normalization of ADCs appeared to poorly predict ultimate tissue recovery since secondary, irreversible damage developed eventually
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