Polynomial approximation of quasipolynomials based on digital filter design principles

This contribution is aimed at a possible procedure approximating quasipolynomials by polynomials. Quasipolynomials appear in linear time-delay systems description as a natural consequence of the use of the Laplace transform. Due to their infinite root spectra, control system analysis and synthesis based on such quasipolynomial models are usually mathematically heavy. In the light of this fact, there is a natural research endeavor to design a sufficiently accurate yet simple engineeringly acceptable method that approximates them by polynomials preserving basic spectral information. In this paper, such a procedure is presented based on some ideas of discrete-time (digital) filters designing without excessive math. Namely, the particular quasipolynomial is subjected to iterative discretization by means of the bilinear transformation first; consequently, linear and quadratic interpolations are applied to obtain integer powers of the approximating polynomial. Since dominant roots play a decisive role in the spectrum, interpolations are made in their very neighborhood. A simulation example proofs the algorithm efficiency. © Springer International Publishing Switzerland 2016

Evaluation of the performances of a single-use duodenoscope: Prospective multi-center national study

Objectives: A single-use duodenoscope (SUD) has been recently developed to overcome issues with endoscopic retrograde cholangiopancreatography (ERCP)-related cross-infections. The aim was to evaluate SUD safety and performance in a prospective multi-centre study. Methods: All consecutive patients undergoing ERCP in six French centers were prospectively enrolled. All procedures were performed with the SUD; in case of ERCP failure, operators switched to a reusable duodenoscope. Study outcomes were the successful completion of the procedure with SUD, safety and operators’ satisfaction based on a VAS 0–10 and on 22 qualitative items. The study protocol was approved by French authorities and registered (ID-RCB: 2020-A00346-33). External companies collected the database and performed statistical analysis. Results: Sixty patients (34 females, median age 65.5 years old) were enrolled. Main indications were bile duct stones (41.7%) and malignant biliary obstruction (26.7%). Most ERCP were considered ASGE grade 2 (58.3%) or 3 (35.0%). Fifty-seven (95.0%) procedures were completed using the SUD. Failures were unrelated to SUD (one duodenal stricture, one ampullary infiltration, and one tight biliary stricture) and could not be completed with reusable duodenoscopes. Median operators’ satisfaction was 9 (7–9). Qualitative assessments were considered clinically satisfactory in a median of 100% of items and comparable to a reusable duodenoscope in 97.9% of items. Three patients (5%) reported an adverse event. None was SUD-related. Conclusions: The use of a SUD allows ERCP to be performed with an optimal successful rate. Our data show that SUD could be used for several ERCP indications and levels of complexity

Lung transplantation for pulmonary fibrosis in dyskeratosis congenita: Case Report and systematic literature review

<p>Abstract</p> <p>Background</p> <p>Dyskeratosis congenita (DC) is a progressive, multi-system, inherited disorder of telomere biology with high risks of morbidity and mortality from bone marrow failure, hematologic malignancy, solid tumors and pulmonary fibrosis. Hematopoietic stem cell transplantation (HSCT) can cure the bone marrow failure, but it does not eliminate the risks of other complications, for which life-long surveillance is required. Pulmonary fibrosis is a progressive and lethal complication of DC.</p> <p>Case presentation</p> <p>In this report, we describe a patient with DC who developed pulmonary fibrosis seven years after HSCT for severe aplastic anemia, and was successfully treated with bilateral lung transplantation. We also performed a systematic literature review to understand the burden of pulmonary disease in patients with DC who did or did not receive an HSCT. Including our patient, we identified 49 DC patients with pulmonary disease (12 after HSCT and 37 without HSCT), and 509 with no reported pulmonary complications.</p> <p>Conclusion</p> <p>Our current case and literature review indicate that pulmonary morbidity is one of the major contributors to poor quality of life and reduced long-term survival in DC. We suggest that lung transplantation be considered for patients with DC who develop pulmonary fibrosis with no concurrent evidence of multi-organ failure.</p

Douze années de pose d’endoprothèses rectocoliques : résultats et suivi chez 204 patients

Objectifs : Les buts de cette étude étaient d’évaluer la faisabilité et l’efficacité à long terme de la mise en place d’endoprothèses métalliques ou plastiques pour des sténoses recto-coliques malignes ou bénignes dans la « vraie vie ». Patients et méthodes : De septembre 1994 à septembre 2006, 204 patients consécutifs (118 femmes, 86 hommes, âge moyen : 73,2 ans, extrêmes : 49-97 ans) présentant une obstruction rectocolique partielle ou complète, étaient traités par une ou plusieurs endoprothèses métalliques ou plastiques. Une pose d’endoprothèse était tentée pour 168 patients porteurs d’une sténose colique maligne en situation palliative, pour 17 malades porteurs également d’un cancer avant un geste chirurgical curatif, pour 19 patients présentant une sténose bénigne, mais contreindiqués pour la chirurgie en raison d’un état général trop altéré. La pose des prothèses était réalisée par voie endoscopique et radioscopique. Différents modèles de prothèses étaient utilisés, incluant les Enteral Wallstent, Wallflex, Colonic Z stent, Ultraflex precision, Choo Stent, Hanarostent et Polyflex. Les données sur l’efficacité de la procédure, les complications et le devenir des patients étaient collectées rétrospectivement à partir des médecins traitants qui ont suivi leurs patients jusqu’à leur décès. Résultats : La pose d’une endoprothèse était effectuée avec succès chez 154 patients en situation palliative (91,6 %), chez les 17 patients avant la chirurgie curative (100 %) et chez 15 malades porteurs d’une sténose bénigne (78 %). Une complication survenait pour 28 patients : perforation colique (n = 8) ; inefficacité (n = 8) ; ré-obstruction par matières fécales ou progression tumorale (n = 6) ; migration (n = 4) ; douleur abdominale sévère (n = 1). Une patiente décédait. Une deuxième endoprothèse était rendue nécessaire ultérieurement chez 6 malades. Conclusions : La pose d’une prothèse rectocolique par voie endoscopique est un traitement palliatif efficace en cas d’obstruction maligne. Ce traitement est également efficace avant un geste chirurgical curatif et pour certaines sténoses bénignes en l’absence d’alternatives thérapeutiques moins agressives

Mesenchymal Stem Cells and Platelet Rich Plasma Therapy to Treat Leak After Sleeve Gastrectomy

Background: One of the most feared and life-threatening complications after sleeve gastrectomy (SG) is staple line leak, with an incidence between 1 and 4%. Stable patients may be managed conservatively, with antibiotics, percutaneous drainage and endoscopy-based treatment. We propose mesenchymal stem cells (MSC) and platelet rich plasma (PRP) therapy as an innovative technique to treat leak after SG. Material and methods: Bone marrow MSCs is obtained by centrifugation of tibial puncture specimen. A peripheral whole blood sample is retrieved from the patient and centrifuged to obtain PRP. During endoscopy, the first 10 mL are injected in 4quadrants (equal volume) in the submucosae around the internal orifice. The second 10 mL are injected in the wall of the fistula tract. Results: The immediate course following the endoscopy was uneventful in both reported cases. The leaks healed in 30 and 42 D, respectively. Oral nutrition was progressively started during the third WK and fourth WK following the injection for both patients. No adverse event was noted during the follow-up period. Conclusion: The management of fistulas post SG is controversial and actual available treatments present a relatively prolonged healing time. MSC administration retains a high potential value in the treatment of these fistulas. Further studies and wider clinical trials are mandatory to determine the impact of MSC administration

Non-Isocyanate Polythiourethanes (NIPTUs) from Cyclodithiocarbonate Telechelic Polyethers

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