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Stress can decrease intragastric pH and cause erosion of gastric mucosa. Because cardiac surgery and cardiopulmonary bypass represent a major stress, the effects on intragastric pH of an H2-receptor antagonist, ranitidine, and an M1-muscarinic antagonist, pirenzepine, were evaluated. Intragastric pH was measured throughout elective cardiac surgery in 60 patients by a digital pH-meter during fentanyl-diazepam-nitrous oxide (50%) anesthesia. The gastric content was sampled at closure of the chest for bacterial count. Oral preoperative medication given randomly included (n = 20 in each group) 0.3 mg/kg diazepam 1 h before induction (group 1); diazepam plus ranitidine (150 mg) 1 h before induction (group 2); and diazepam plus pirenzepine (50 mg) on the evening before surgery and 1 h before induction of anesthesia (group 3). At induction intragastric pH was higher in group 2 (mean +/- SD = 7.42 +/- 1.07) than in group 1 (5.28 +/- 2.14) (P less than 0.01) but was not significantly different in group 3 (5.78 +/- 1.89) than in group 1. In no group did intragastric pH change significantly during surgery. Gastric juice was sterile in 92% of group 1, in 25% of group 2, and in 71% of group 3 patients (P less than 0.01). Postoperatively no gastrointestinal complications occurred, but there was a trend toward more patients developing nosocomial pneumonias in groups 2 and 3 (15%) than in group 1 (0%) (P = 0.06). Intraoperative intragastric pH is relatively high after diazepam premedication, thus the preoperative addition of ranitidine or pirenzepine would not be necessary and may possibly be hazardous.

Les technologies informatiques et de la commande ne sont pas uniquement de l’ordre des techni-sciences mais interviennent dans la production de subjectivite. On ne peut pas separer ces transformations des bouleversements politiques en cours. Le primat porte sur l’information comme nouvelle categorie, a cote de l’energie, accentue la production de nouvelles subjectivites et peut transformer la societe en une societe de communication. Mais ce concept est insuffisant si on ne l’associe pas a une « fonction existentielle » qui rende compte de la desaxation generalisee des coordonnees subjectives. La problematique de la recomposition subjective doit etre posee par une re-finalisation des processus d’information, de telematisation, etc., sur d’autres systemes de valeurs, du niveau de l’ecologie mentale, jusqu’aux niveaux les plus planetaires. Nous sommes en co-pilotage avec une nature en situation. L’element etonnant de cette symbiose, c’est la transformation radicale des rapports, des uns et avec les autres. L’ecologie est un grand tournant, a condition que cette ecologie soit mariee a la dimension sociale et economique, avec toute forme d’alterite, pour former une ideologie douce, qui fasse sa place aux nouvelles connaissances.

Background A simplified alternative to the Cox maze procedure to treat atrial fibrillation with epicardial high-intensity focused ultrasound was evaluated clinically, and the initial clinical results were assessed at the 6-month follow-up visit. Methods From September 2002 through February 2004, 103 patients were prospectively enrolled in a multicenter study. Atrial fibrillation duration ranged from 6 to 240 months (mean, 44 months) and was permanent in 76 (74%) patients, paroxysmal in 22 (21%) patients, and persistent in 5 (5%) patients. All patients had concomitant operations, and ablation was performed epicardially on the beating heart before the concomitant procedure. The device automatically created a circumferential left atrial ablation around the pulmonary veins in an average of 10 minutes, and an additional mitral line was created epicardially in 35 (34%) patients with a handheld device by using the same technology. Results No complications or deaths were device or procedure related. There were 4 (3.8%) early deaths and 2 late extracardiac deaths. The 6-month follow-up was complete in all survivors. At the 6-month visit, freedom from atrial fibrillation was 85% in the entire study group (80% in patients with permanent atrial fibrillation, 88% in the 35 patients who had the additional mitral line, and 100% in patients with paroxysmal atrial fibrillation). A pacemaker was implanted in 8 patients. Only the duration and type of atrial fibrillation significantly increased the risk of recurrence. Conclusion Epicardial, off-pump, beating-heart ablation with acoustic energy is safe and cures 80% of patients with permanent atrial fibrillation associated with long-standing structural heart disease.

In the presence of ethylene glycol, poly(ethylene terephthalate) (PET) undergoes chain scissions with the formation of α,ω-hydroxyl oligomers, through classical transesterification by alcoholysis. e-Caprolactone was subsequently added on the hydroxyl end groups of PET oligomers by ring-opening polymerization at different molar ratios of e-caprolactone to PET oligomers. The chemical structure of the products was investigated by size exclusion chromatography, 1 H NMR spectroscopy, and differential scanning calorimetry. A large majority of these products are soluble in common organic solvents. The thermal and 1 H NMR analyses reveal that the transesterification between base units of PET oligomers and e-caprolactone during the synthesis is always present whatever the reaction conditions. This phenomenon leads to copolymers having thermal properties different from those of PET. However, some cooligomers present the interest of keeping properties close to those of PET. The main purpose of this study was the synthesis of PET co-oligomers that are soluble in some organic solvents that would make their use easier, and so that they can be used further as hard segment precursers for polycondensation reactions.

An inductively coupled argon plasma was evaluated as a source for the determination of oscillator strength values of several lines of Ta I and Ta II. Although there is a departure from LTE, a partial LTE between excited states of injected elements was assumed. This allowed the authors to consider an excitation temperature of 4800 K in the determination of ƒ-values of tantalum.

Resume Un nouveau generateur haute frequence de plasma fonctionnant a 40 MHz a ete concu comme source d'excitation en spectroscopie d'emission atomique et source d'atomisation en absorption atomique. De bonnes performances analytiques ont ete obtenues en emission et en absorption atomique. On peut neanmoins preferer l'emission pour sa simplicite de mise en oeuvre.

Resume Une etude des interferences chimiques et d'ionisation a ete realisee dans un plasma induit par haute frequence utilise comme source d'excitation en spectroscopie atomique. Du fait de la temperature elevee (6000 K), les interferences chimiques sont negligeables. Les interactions produites par la prese signal du phosphore et plus faiblement du chrome, non influences sur d'autres elements) ne peuvent s'expliquer par un changement de l'equilibre des particules dans le plasma (loi de Saha), la densite electronique et la temperature mesurees en fonction de la concentration en sodium ne variant pas de faccon appreciable.

Telechelic oligo(dimethylsiloxane)s 6 and 7 with chloro-, cyano- or aminopropyl end groups were synthesized from the corresponding chlorodimethylsilanes 2a–c and α-hydro-ω-hydroxyoligo(dimethylsiloxane)s 4 and 5. The ω-cyano derivatives 6b and 7b were reduced to the 4-aminobutyl derivatives 8a and 8b with LiAlH4. 8a was subsequently transformed into 1,7-bis(4-maleimidobutyl)-1,1,3,3,5,5,7,7-octamethyltetrasiloxane (10) by reaction with maleic anhydride, via the intermediate dimaleamic acid 9. The products were characterized by IR, 1H, 29Si, and 13C NMR spectroscopy.

This paper describes software for automatic qualitative and semi-quantitative analysis using inductively coupled plasma (ICP) atomic emission spectrometry with a high-resolution scanning monochromator. This software can be also used for automatic collection of wavelengths and intensities of spectral lines emitted from an ICP.

Telechelic aromatic diamines (11) containing an oligo- or polysiloxane chain were prepared in a 4-step synthesis. In the first step 1-allyloxy-4-nitrobenzene (6) was synthesized and subsequently hydrosilylated with chlorodimethylsilane. In the third step the product (7) was hydrolyzed or condensed with α-hydro-β-hydroxyoligo- or polydimethylsiloxane (9a or 9b). In the last step the nitro groups were reduced into amino groups. The steps were controlled by means of 1H and 29Si NMR spectroscopy.

In an HF plasma at 40 MHz, physical parameters such as the excitation temperature of different elements (Ar, Ti, Fe, V), the electron number density on the basis of profiles of argon (549.5 nm) and hydrogen (Hβ) lines and the ionization temperatures of Mg and V were determined. A study of the smoothing of experimental curves was made in order to apply Abel transformation. Consistent values were obtained by smoothing the curves by means of C hebyshev's orthogonal polynomial method and by the method of least squares. The experimental results showed agreement between the excitation temperatures of the elements indicated (4800 K). The electron number density obtained from the profile of lines broadened by the Stark effect is about 5.5 × 1014 cm−3. The ionization temperature of Ar derived from the Saha equation under assumption of complete LTE (7400 K) differs substantially from the excitation temperature and indicates that complete LTE does not exist. However ionization temperatures calculated by the method of the ratio of ion and atom line intensities, associated with Texc and ne values, are 7300 K for Mg and 6700 K for V but are not significantly different from each other.

Objective: The ideal substitute for the treatment of ventricle–pulmonary artery discontinuity remains a topic of controversy, because of calcifications and degeneration of biologic substitutes leading to subsequent reoperations. Because polyurethane valves used in ventricular assist devices show a satisfactory biocompatibility, the aim of this study was to evaluate a valved conduit composed of a Dacron graft incorporating a trileaflet 25 mm polyurethane valve. Methods: The conduit was implanted between the right ventricle and the main pulmonary artery in adult sheep, with ligation of the proximal pulmonary artery. The animals received no medications. Serial hemodynamic data were collected at the time of implantation and at postoperative intervals of 6 and 12 months. Results: The peak pressure gradient across the valve increased significantly between implantation (0.17 ± 5.6 mm Hg) and 6 months after operation (7.3 ± 3 mm Hg, p = 0.0007) and remained stable thereafter (6.7 ± 3 mm Hg at 12 months), whereas the cardiac output remained unchanged (4.6 ± 0.6 L/min at implantation, 4 ± 0.6 L/min at 6 months, and 3.9 ± 1.1 L/min at 12 months). At the completion of the study, valve samples were processed and vapor coated with carbon for microscopic examination. There was one instance of nonadherent thrombus formation inside a cusp but no structural failures. The other valves were free of calcium deposits and no significant amounts of phosphorus could be detected by scanning electron microscopy and energy dispersive spectrometry. Conclusions: These data demonstrate the good hemodynamic performance, low thrombogenicity, and acceptable durability of the polyurethane valves implanted in the right side of the heart in a chronic sheep model. (J Thorac Cardiovasc Surg 1998;115:898-903)

Contexte : la pandémie de Covid-19 a nécessité une réorientation des ressources humaines notamment du bloc opératoire vers les unités de soins intensifs. L'objectif de cette étude est d'évaluer l'impact de la pandémie de COVID-19 sur l'activité chirurgicale 2020, de transplantation d'organes et de soins intensifs dans un hôpital universitaire français. Méthode : une étude observationnelle rétrospective a été réalisée sur les données de chirurgie cardiaque, thoracique et digestive pour les années 2019 et 2020. Les données ont été recueillies à l'aide d'une base de données numérique pour l'activité chirurgicale et d'un recueil systématique de l'activité dans les unités de soins intensifs. Toutes les activités ont été comparées mois par mois entre 2020 et 2019. Résultats : au total, l'activité chirurgicale a diminué de -10% entre 2020 et 2019, l'activité de transplantation de -25% et l'activité de réanimation de -5%. La chirurgie ayant connu la baisse la plus importante est la chirurgie cardiaque conventionnelle avec une baisse de -18%. En ce qui concerne les chirurgies thoracique et digestive, cette baisse est principalement due au report de chirurgies mineures non urgentes. Les mois ayant connu la baisse la plus importante sont les mois de mars, avril, mai et novembre, correspondant aux deux vagues de la pandémie de Covid en France. Conclusion : une nette baisse d'activité a été observée pendant les pics de l'épidémie, tant au bloc opératoire que dans les unités de soins intensifs. Ceci représente un véritable défi pour l’avenir : réussir à prendre en charge les patients Covid sans retarder ni entraver la prise en charge des patients non-Covid.

In the context of recycling plastic matter from waste, we study here polyethylene terephthalate (PET) because of its abundance in packaging. Because of its low viscosity, we blend it with high-density polyethylene (HDPE) in order to obtain a good extrudability. The reprocessing appears as a particular case of the processing of polymer blends, with the classical problem of incompatibility which induces poor mechanical properties. In order to extrude PET, we studied the SCAMIA extrusion reprocessing and its influence on PET and PET/HDPE blends. More precisely, we worked on their rheological behaviour, on the structure development and on the mechanical properties of the extruded materials. We found good interaction between PET and HDPE (double skin/core structure of the PET, positive influence of HDPE) involving good mechanical properties. It has been shown that, by appropriate processing conditions (especially the use of a cold die) inducing double structure and morphological orientation, it is possible to extrude PET, to prepare blends with HDPE and to keep good properties.; Cette étude s'inscrit dans le cadre du recyclage des déchets de polyéthylène téréphtalate (PET) qui constitue un gisement abondant en raison de son emploi dans le secteur de l'emballage. Ce polymère étant un thermoplastique, la valorisation mécanique apparaît comme une méthode de choix pour le recycler. Toutefois, en raison de sa faible viscosité et donc de sa faible "extrudabilité", nous avons décidé de l'utiliser en mélange avec le polyéthylène haute densité (PEhd). L'enjeu de nos travaux a donc consisté à trouver des solutions pour extruder le PET et ses mélanges sous forme de profilés en assurant aux matériaux extrudés de bonnes propriétés mécaniques. Pour ce faire, nous avons étudié le procédé de mise en oeuvre SCAMIA et son impact sur les mélanges PET/PEhd, et notamment le comportement rhéologique des mélanges à l'état fondu, les mécanismes d'établissement de la morphologie et les propriétés mécaniques des pièces extrudés. Nous avons montré que le procédé SCAMIA et plus précisément l'utilisation de la filière froide permettait de contrôler la morphologie du PET et de ses mélanges. La formation d'une double structure cœur/peau du PET renforcée par la présence du PEhd leur assure des propriétés mécaniques satisfaisantes sans ajout de compatibilisant.