University of Lorraine

About: University of Lorraine is a education organization based out in Nancy, France. It is known for research contribution in the topics: Population & Nonlinear system. The organization has 11942 authors who have published 25010 publications receiving 425227 citations. The organization is also known as: Lorraine University.

Efficient Model Learning Methods for Actor–Critic Control

Abstract: We propose two new actor-critic algorithms for reinforcement learning Both algorithms use local linear regression (LLR) to learn approximations of the functions involved A crucial feature of the algorithms is that they also learn a process model, and this, in combination with LLR, provides an efficient policy update for faster learning The first algorithm uses a novel model-based update rule for the actor parameters The second algorithm does not use an explicit actor but learns a reference model which represents a desired behavior, from which desired control actions can be calculated using the inverse of the learned process model The two novel methods and a standard actor-critic algorithm are applied to the pendulum swing-up problem, in which the novel methods achieve faster learning than the standard algorithm

Current use of vasopressors in septic shock.

Abstract: imed to evaluate the current practice and therapeutic goals regarding vasopressor use in septic shock as a basis for future studies and to provide some recommendations on their use. Methods: From November 2016 to April 2017, an anonymous web-based survey on the use of vasoactive drugs was accessible to members of the European Society of Intensive Care Medicine (ESICM). A total of 17 questions focused on the profle of respondents, triggering factors, frst choice agent, dosing, timing, targets, additional treatments, and efects of vasopressors. We investigated whether the answers complied with current guidelines. In addition, a group of 34 international ESICM experts was asked to formulate recommendations for the use of vasopressors based on 6 questions with sub-questions (total 14). Results: A total of 839 physicians from 82 countries (65% main specialty/activity intensive care) responded. The main trigger for vasopressor use was an insufcient mean arterial pressure (MAP) response to initial fuid resuscitation (83%). The frst-line vasopressor was norepinephrine (97%), targeting predominantly a MAP>60–65 mmHg (70%), with higher targets in patients with chronic arterial hypertension (79%). The experts agreed on 10 recommendations, 9 of which were based on unanimous or strong (≥80%) agreement. They recommended not to delay vasopressor treatment until fuid resuscitation is completed but rather to start with norepinephrine early to achieve a target MAP of≥65 mmHg. Conclusion: Reported vasopressor use in septic shock is compliant with contemporary guidelines. Future studies should focus on individualized treatment targets including earlier use of vasopressors.

Systematic review: The epidemiology of the hepatobiliary manifestations in patients with inflammatory bowel disease.

Abstract: SummaryBackground Extraintestinal manifestations are frequent in inflammatory bowel diseases (IBD). Most studies published so far focused on viral hepatitis and liver toxicity of IBD-related drugs. Aim To conduct a systematic review of hepatobiliary manifestations associated with IBD. We excluded viral hepatitis and liver toxicity of IBD-related drugs. Methods Studies were identified through the electronic database of MEDLINE, EMBASE and the annual meetings of Digestive Disease Week, the American College of Gastroenterology, the United European Gastroenterology Week and the European Crohn's and Colitis Organization. Results One hundred and forty six articles were included in this systematic review. Cholelithiasis is more frequent in Crohn's disease (CD) than in general population. Prevalence of cholelithiasis in CD ranged from 11% to 34%, whereas it ranges from 5.5% to 15% in non-IBD patients. PSC is more frequent in UC than in CD. Prevalence of PSC ranges from 0.76% to 5.4% in UC and from 1.2% to 3.4% in CD. There is a male predominance when PSC is associated with UC, with a male/female ratio ranging from 65/35 to 70/30. No conclusion can be made on a possible increased risk of gall-bladder carcinoma. Mean prevalence of fatty liver is 23% (range, 1.5–55%). Hepatic amyloidosis occurs in less than 1% of IBD. Liver abscess is encountered mainly in CD. Portal vein thrombosis occurs in 39% to 45% of IBD patients undergoing proctocolectomy. Conclusions Hepatobiliary manifestations associated with inflammatory bowel diseases are frequent and probably underdiagnosed.

Tensile and impact properties of microcellular isotactic polypropylene (PP) foams obtained by supercritical carbon dioxide

Abstract: Microcellular isotactic polypropylene (PP) foams with various cell sizes (1–50 μm) and relative densities (0.86–0.04) were prepared using supercritical carbon dioxide (CO 2 ) solid-state foaming to investigate the relationship between the cell morphologies and mechanical properties (tensile and impact). The tensile modulus of the PP foams decreased proportionally with the square of their relative densities and was always smaller than that of the un-foamed PP. Contrary to the tensile modulus, other properties, namely, tensile strength at break, elongation at break and impact strength of the PP foams, outperformed the un-foamed PP with margins that depended on the relative densities and cell sizes of the foams. PP foams with cell sizes less than 3 μm showed higher tensile strength at break than the un-foamed PP. During tensile deformation, cells stretched from circular shapes to elliptical ones. They collapsed or broke at very high deformation. Small cells (less than 3 μm) were found to significantly reduce the stress concentration under loading. Additionally, PP foams with cell sizes less than 10 μm showed higher elongation at break and impact strength compared with that of the un-foamed PP. During the impact, the cell size and cell density both decreased gradually along the impact direction. Furthermore, a plastic deformation zone occurred when the cell size was less than 10 μm, indicating that size reduction and collapse of cells could absorb a significant amount of impact energy.

Protein docking using case-based reasoning.

Abstract: Protein docking algorithms aim to calculate the three-dimensional (3D) structure of a protein complex starting from its unbound components. Although ab initio docking algorithms are improving, there is a growing need to use homology modeling techniques to exploit the rapidly increasing volumes of structural information that now exist. However, most current homology modeling approaches involve finding a pair of complete single-chain structures in a homologous protein complex to use as a 3D template, despite the fact that protein complexes are often formed from one or more domain-domain interactions (DDIs). To model 3D protein complexes by domain-domain homology, we have developed a case-based reasoning approach called KBDOCK which systematically identifies and reuses domain family binding sites from our database of nonredundant DDIs. When tested on 54 protein complexes from the Protein Docking Benchmark, our approach provides a near-perfect way to model single-domain protein complexes when full-homology templates are available, and it extends our ability to model more difficult cases when only partial or incomplete templates exist. These promising early results highlight the need for a new and diverse docking benchmark set, specifically designed to assess homology docking approaches.