Molecular and isotopic characterization of biomarkers in the Frick Swiss Jura sediments: A palaeoenvironmental reconstruction on the northern Tethys margin

Molecular and stable carbon isotope compositions of source-specific hydrocarbons have been used to reconstruct palaeoenvironmental conditions during deposition of the Middle Hettangian to Upper Sinemurian sediments on the northern epicontinental Tethys margin, Frick Swiss Jura. Increasing algal, cyanobacterial and phytoplanktonic (i.e., dinoflagellate) contributions associated with the C-13-enrichment of cyanobacteria derivatives (i.e., hopanes and monomethylalkanes) suggest enhanced primary productivity upsection. This is related to the C-13-enrichment of dissolved CO2 in the upper layers and the progressive increase of depth and oxygenation of the water column. In the Middle Hettangian shallow-water environments (lagoon), the occurrence of green sulfur bacteria (Chlorobiaceae) derivatives indicates that the lower part of the water column was strictly anoxic and rich in H2S. Since these bacteria require very low light intensity to grow, these euxinic conditions may be extended up to the photic zone, allowing for anaerobic photosynthesis. Light penetration depth is most likely reduced by high productivity and/or turbidity in the photic zone. In these sediments, C-13-depleted hopanoids (-39.5 parts per thousand) are most likely associated with phototrophic purple sulfur bacteria utilizing isotopically light organic carbon at the base of the aerobic zone. These purple sulfur bacteria may have consumed the H2S used by Chlorobiaceae in the deeper layers and thus, sustained the algae and cyanobacteria productivity in the upper layers. The C-13-depleted carbonate (-13.3 parts per thousand) may be partially related to the anaerobic oxidation of the organic matter during bacterial sulfate-reduction. (c) 2006 Elsevier Ltd. All rights reserved.

Are virtual planning and guided surgery for head and neck reconstruction economically viable?

PURPOSE: Virtual planning and guided surgery with or without prebent or milled plates are becoming more and more common for mandibular reconstruction with fibular free flaps (FFFs). Although this excellent surgical option is being used more widely, the question of the additional cost of planning and cutting-guide production has to be discussed. In capped payment systems such additional costs have to be offset by other savings if there are no special provisions for extra funding. Our study was designed to determine whether using virtual planning and guided surgery resulted in time saved during surgery and whether this time gain resulted in self-funding of such planning through the time saved. MATERIALS AND METHODS: All consecutive cases of FFF surgery were evaluated during a 2-year period. Institutional data were used to determine the price of 1 minute of operative time. The time for fibula molding, plate adaptation, and insetting was recorded. RESULTS: During the defined period, we performed 20 mandibular reconstructions using FFFs, 9 with virtual planning and guided surgery and 11 freehand cases. One minute of operative time was calculated to cost US $47.50. Multiplying this number by the time saved, we found that the additional cost of virtual planning was reduced from US $5,098 to US $1,231.50 with a prebent plate and from US $6,980 to US $3,113.50 for a milled plate. CONCLUSIONS: Even in capped health care systems, virtual planning and guided surgery including prebent or milled plates are financially viable.

Laryngotracheal reconstruction for pediatric glotto-subglottic stenosis.

BACKGROUND: The management of pediatric laryngotracheal stenosis (LTS) can be challenging, and laryngotracheal reconstruction (LTR) with cartilage interposition grafting remains the mainstay of surgical treatment for pediatric LTS in most experienced centers. The purpose of this study was to report the results of this procedure in a center where primary cricotracheal resection is frequently performed. METHODS: A retrospective chart review was performed on 45 patients who underwent LTR in our hospital between October 1997 and July 2012. Demographic characteristics and information on the preoperative status, stenosis, and operation were collected. Primary outcomes were measured as overall (ODR) and operation-specific (OSDR) decannulation rates and secondary outcomes as morbidity, mortality, and postoperative functional results. RESULTS: ODR and OSDR were 86.7% (39/45) and 66.7% (30/45), respectively. Re-stenosis was observed in 11/45 (24%) patients, all of whom were endoscopically or surgically treated. Revision surgery was performed in 10 patients, 6 for re-stenosis and 2 for peristomial tracheomalacia. Two children died of mucous obstruction of tracheostomy tube at 3 and 6 months postoperatively (4.4%). Respiratory, voice, and swallowing functions were excellent or good in 86, 75, and 84% of patients, respectively. CONCLUSIONS: LTR for pediatric LTS has high decannulation rates with acceptable morbidity and mortality in selected patients. Most LTR procedures were double-stage for lower grade subglottic stenoses associated with glottic involvement that required stenting. Careful preoperative evaluation and adequate surgical indications are extremely important to achieve high decannulation rates.

Groundwater dating and past climate reconstruction

In the past decade aquifers have increasingly become palaeoclimatic archives in their own right alongside ice cores, sediments and other proxy records. The main tool for this task has been the noble gas palaeo-thermometer in combination with quantitative groundwater dating using radionuclides. Noblegas radionuclides play a unique role as tracers in environmental studies due to their chemical inertness and low concentration making them ideal tracers. The same properties on the other hand make them difficult to measure on natural concentration levels. Therefore for decades low level counting (LLC) was the only method for detecting radioisotopes of argon and krypton at an atmospheric level. In recent times and with the increase of interest and potential applications the analytical efforts with novel detection methods have been intensified. In the talk noble gas groundwater dating techniques over times scales from decades to millions of years are discussed in relation to noble gas palaeo records at different locations in Europe and elsewhere.

La reconnaissance et le sens du travail : deux dimensions au coeur des processus de préservation de la santé mentale chez les professionnels des interventions d'urgences médicales préhospitalières

Le travail en situations d'urgence, notamment médicale, comporte de nombreux facteurs de risque pour la santé mentale. Cependant, des études récentes suggèrent que la reconnaissance de même que certains aspects relatifs au sens du travail pourraient permettre aux individus de préserver leur équilibre psychique malgré la présence de stresseurs importants.Nous avons effectué une étude portant sur la santé au travail pour des ambulanciers travaillant en Suisse romande. Dans un premier temps, une phase qualitative centrée sur l'observation du travail réel a été effectuée. Les observations ont été effectuées dans 11 services pour un total de 416 heures d'observation. Dans un second temps, un questionnaire a été développé et administré à l'ensemble des ambulanciers de Suisse romande.Notre étude a notamment permis de confirmer l'importance de la reconnaissance et du sens du travail pour les ambulanciers. [Auteurs]

A methodology to event reconstruction from trace images

The widespread use of digital imaging devices for surveillance (CCTV) and entertainment (e.g., mobile phones, compact cameras) has increased the number of images recorded and opportunities to consider the images as traces or documentation of criminal activity. The forensic science literature focuses almost exclusively on technical issues and evidence assessment [1]. Earlier steps in the investigation phase have been neglected and must be considered. This article is the first comprehensive description of a methodology to event reconstruction using images. This formal methodology was conceptualised from practical experiences and applied to different contexts and case studies to test and refine it. Based on this practical analysis, we propose a systematic approach that includes a preliminary analysis followed by four main steps. These steps form a sequence for which the results from each step rely on the previous step. However, the methodology is not linear, but it is a cyclic, iterative progression for obtaining knowledge about an event. The preliminary analysis is a pre-evaluation phase, wherein potential relevance of images is assessed. In the first step, images are detected and collected as pertinent trace material; the second step involves organising and assessing their quality and informative potential. The third step includes reconstruction using clues about space, time and actions. Finally, in the fourth step, the images are evaluated and selected as evidence. These steps are described and illustrated using practical examples. The paper outlines how images elicit information about persons, objects, space, time and actions throughout the investigation process to reconstruct an event step by step. We emphasise the hypothetico-deductive reasoning framework, which demonstrates the contribution of images to generating, refining or eliminating propositions or hypotheses. This methodology provides a sound basis for extending image use as evidence and, more generally, as clues in investigation and crime reconstruction processes.

Iterative reconstruction methods in two different MDCT scanners: Physical metrics and 4-alternative forced-choice detectability experiments - A phantom approach.

This paper characterizes and evaluates the potential of three commercial CT iterative reconstruction methods (ASIR?, VEO? and iDose(4 ()?())) for dose reduction and image quality improvement. We measured CT number accuracy, standard deviation (SD), noise power spectrum (NPS) and modulation transfer function (MTF) metrics on Catphan phantom images while five human observers performed four-alternative forced-choice (4AFC) experiments to assess the detectability of low- and high-contrast objects embedded in two pediatric phantoms. Results show that 40% and 100% ASIR as well as iDose(4) levels 3 and 6 do not affect CT number and strongly decrease image noise with relative SD constant in a large range of dose. However, while ASIR produces a shift of the NPS curve apex, less change is observed with iDose(4) with respect to FBP methods. With second-generation iterative reconstruction VEO, physical metrics are even further improved: SD decreased to 70.4% at 0.5 mGy and spatial resolution improved to 37% (MTF(50%)). 4AFC experiments show that few improvements in detection task performance are obtained with ASIR and iDose(4), whereas VEO makes excellent detections possible even at an ultra-low-dose (0.3 mGy), leading to a potential dose reduction of a factor 3 to 7 (67%-86%). In spite of its longer reconstruction time and the fact that clinical studies are still required to complete these results, VEO clearly confirms the tremendous potential of iterative reconstructions for dose reduction in CT and appears to be an important tool for patient follow-up, especially for pediatric patients where cumulative lifetime dose still remains high.