140 research outputs found
Pump-and-probe optical transmission phase shift as a quantitative probe of the Bogoliubov dispersion relation in a nonlinear channel waveguide
We theoretically investigate the dispersion relation of small-amplitude
optical waves superimposing upon a beam of polarized monochromatic light
propagating along a single-mode channel waveguide characterized by an
instantaneous and spatially local Kerr nonlinearity. These small luminous
fluctuations propagate along the waveguide as Bogoliubov elementary excitations
on top of a one-dimensional dilute Bose quantum fluid evolve in time. They
consequently display a strongly renormalized dispersion law, of Bogoliubov
type. Analytical and numerical results are found in both the absence and the
presence of one- and two-photon losses. Silicon and silicon-nitride waveguides
are used as examples. We finally propose an experiment to measure this
Bogoliubov dispersion relation, based on a stimulated four-wave mixing and
interference spectroscopy techniques.Comment: 17 pages, 7 figure
Évaluation des compétences pratiques en fin de deuxième cycle des études médicales : exemple du drainage du bas appareil urinaire
IntroductionLe drainage vésical peut, mal pratiqué, être iatrogène en se compliquant notamment d’infections et de traumatismes de l’appareil urinaire. Cette étude a pour objectif de déterminer la capacité des étudiants en médecine de fin de deuxième cycle à pratiquer les différents moyens de drainage des urines. Matériel et méthodes Entre janvier et mars 2007, un questionnaire d’autoévaluation des compétences de drainage urinaire a été envoyé par mail à un échantillon représentatif d’étudiants en médecine en dernière année d’externat, soit deux mois avant l’épreuve de l’examen national classant. Résultats Deux cent soixante-dix-sept réponses ont été reçues et analysées. Soixante-douze étudiants (26 %) jugeaient qu’ils maîtrisaient le cathétérisme urétrovésical chez l’homme et 106 étudiants (38,3 %) chez la femme à la fin de leur externat. Soixante et onze étudiants sur les 277 (25,5 %) avaient effectué un stage en urologie au cours de leur cursus. Parmi eux, 53,5 % estimaient acquis le sondage à demeure (SAD) chez l’homme (p < 0,001) et 39 (54,9 %) chez la femme (p < 0,001). Soixante-treize étudiants (26,4 %) estimaient qu’ils maîtrisaient le sondage minute d’une femme ou d’un homme et un seul considérait la pose de cathéter sus-pubien comme acquis. Conclusion L’apprentissage des gestes de drainage urinaire est enseigné de façon inappropriée au cours des études médicales puisque de jeunes médecins se sentent incapables de les reproduire au terme de leur externat. Cela est critiquable, car le sondage doit pouvoir être réalisé par tous médecins non urologues dans leur pratique quotidienne, notamment en terrain hospitalier. Cette étude doit mener à une réflexion sur l’amélioration de l’enseignement des gestes pratiques médicaux essentiels pendant l’externat
Photosynthetic pigment levels in Macroptilium lathyroides L under water deficit.
TĂtulo em espanhol: Contenido de pigmentos fotosinteticos Macroptilium lathyroides L en condiciones de sequia
Wheat amylase/trypsin inhibitors (ATIs): occurrence, function and health aspects
Amylase/trypsin inhibitors (ATIs) are widely consumed in cereal-based foods and have been implicated in adverse reactions to wheat exposure, such as respiratory and food allergy, and intestinal responses associated with coeliac disease and non-coeliac wheat sensitivity. ATIs occur in multiple isoforms which differ in the amounts present in different types of wheat (including ancient and modern ones). Measuring ATIs and their isoforms is an analytical challenge as is their isolation for use in studies addressing their potential effects on the human body. ATI isoforms differ in their spectrum of bioactive effects in the human gastrointestinal (GI), which may include enzyme inhibition, inflammation and immune responses and of which much is not known. Similarly, although modifications during food processing (exposure to heat, moisture, salt, acid, fermentation) may affect their structure and activity as shown in vitro, it is important to relate these changes to effects that may present in the GI tract. Finally, much of our knowledge of their potential biological effects is based on studies in vitro and in animal models. Validation by human studies using processed foods as commonly consumed is warranted. We conclude that more detailed understanding of these factors may allow the effects of ATIs on human health to be better understood and when possible, to be ameliorated, for example by innovative food processing. We therefore review in short our current knowledge of these proteins, focusing on features which relate to their biological activity and identifying gaps in our knowledge and research priorities
Double-J ureteral stent under local anesthesia for women
INTRODUCTION: Ureteral stent placement is a key urologic procedure used to manage ureteral obstructions. It is usually performed under general anesthesia (GA) with its inherent risks. The objective was to evaluate safety, feasibility and tolerance of ureteral stent placement under local anesthesia (LA) in women. MATERIALS AND METHODS: From January 2010 to January 2013, we prospectively and consecutively reviewed all female patients who had an urgent retrograde ureteral stent placement under LA. Only primary stent placements were included in the study. Pain was assessed after surgery by Visual Analog Scale (VAS) and pain and comfort assessment during stent placement were reported. We compared outcomes and tolerance with patients under general anesthesia (GA) matched by age and operatives indications during the same period. RESULTS: We included 36 patients (18 under LA and 18 under GA) with a mean age of 59.4 +/- 22.4 years. The mean operative time was 24.4 +/- 12.9 min and 18.8 +/- 6.5 min in LA group and GA group (p = 0.110), respectively. One patient needed GA due to a poor tolerance. The mean perioperative VAS scores under LA and GA were 5.89 +/-2.95 and 2.06 +/- 2.67 (p < 0.0001), respectively. There were no intraoperative complications in either group. The procedure was painful for 16 (88.8%) patients from the LA group and 9 (50%) patients would not accept to undergo this intervention under LA again. CONCLUSION: Ureteral stent placement under LA in women can be performed safely and effectively. However, this procedure is painful and should be proposed only to selected cases
Successful medical treatment of glans ischemia after voluntary buprenorphine injection
INTRODUCTION: The diverted use of synthetic opioid buprenorphine by drug addicts can be responsible for serious ischemic and infectious complications, particularly in the case of intravenous injection. AIM: We present a case of serious glans ischemia after buprenorphine injection directly into the deep dorsal vein of the penis. Analysis using new medical imaging techniques and treatments is detailed below. METHODS: A 26-year-old male drug addict presented with glans pain 4 days after self-injection of buprenorphine into the deep dorsal vein of the penis. The patient was apyretic and presented a urethral discharge. His glans was blue without discoloration on digital pressure. Additionally, his biologic and serologic tests were normal while bacteriology showed the presence of Enterobacter cloacae urethritis. RESULTS: After 48 hours of intravenous antibiotic treatment without improvement, a specific medical treatment using enoxaparin and ilomedin was initiated, with the assumption that there was an ischemic complication. Laser speckle contrast imaging allowed confirmation of the presence of distal penis ischemia and provided an accurate mapping of the ischemic zone. A 28-day treatment combining antibiotics, subcutaneous heparin at curative dose, antiplatelet drug, ilomedin, and hyperbaric oxygen therapy resulted in clinical improvement of the lesions with no functional complications. CONCLUSIONS: To date, no consensus exists on the proper diagnostic and treatment approach to severe glans ischemia due to buprenorphine injection into the deep dorsal vein of the penis. The results of laser speckle contrast imaging were of real interest during the process of diagnosis. In addition, the combination of ilomedin with hyperbaric oxygen therapy and anticoagulant and antiplatelet drugs appeared to be an effective therapy
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