Analyse et optimisation des procédés de conception des systèmes de transmission Nx160 Gb/s par fibre à haute densité de gestion de la dispersion

DIJON-BU Sciences Economie (212312102) / SudocSudocFranceF

Dispersive wave emission in dual concentric core fiber: the role of soliton-soliton collisions

Soliton–soliton collisions have a crucial role in enhancing the spectrum of dispersive waves in optical fibers and collisions among in-phase solitons lead to a dramatic enhancement of the dispersive wave power, as well as to its significant spectral reshaping. We obtained a simple analytical model to estimate the spectral position, width, and amplitude of the dispersive waves induced by a collision of two in-phase solitons. We tested our theory in the case of a dual concentric core microstructured fiber

Hepatic Notch2 deficiency leads to bile duct agenesis perinatally and secondary bile duct formation after weaning

("control") mice. Fetal and neonatal Notch2-cKO livers were devoid of cytokeratin19 (CK19)-, Dolichos-biflorus agglutinin (DBA)-, and SOX9-positive ductal structures, demonstrating absence of prenatal cholangiocyte differentiation. Despite extensive cholestatic hepatocyte necrosis and growth retardation, mortality was only ~15%. Unexpectedly, a slow process of secondary cholangiocyte differentiation and bile-duct formation was initiated around weaning that histologically resembled the ductular reaction. Newly formed ducts varied from rare and non-connected, to multiple, disorganized tubular structures that connected to the extrahepatic bile ducts. Jaundice had disappeared in ~30% of Notch2-cKO mice by 6 months. The absence of NOTCH2 protein in postnatally differentiating cholangiocyte nuclei of Notch2-cKO mice showed that these cells had not originated from non-recombined precursor cells. Notch2 and Hnf6 mRNA levels were permanently decreased in Notch2-cKO livers. Perinatally, Foxa1, Foxa2, Hhex, Hnf1β, Cebpα and Sox9 mRNA levels were all significantly lower in Notch2-cKO than control mice, but all except Foxa2 returned to normal or increased levels after weaning, coincident with the observed secondary bile-duct formation. Interestingly, Hhex and Sox9 mRNA levels remained elevated in icteric 6 months old Notch2-cKOs, but decreased to control levels in non-icteric Notch2-cKOs, implying a key role in secondary bile-duct formation. Conclusion: Cholangiocyte differentiation becomes progressively less dependent on NOTCH2 signaling with age, suggesting that ductal-plate formation is dependent on NOTCH2, but subsequent cholangiocyte differentiation is not

Pneumocystis pneumonia in intensive care: clinical spectrum, prophylaxis patterns, antibiotic treatment delay impact, and role of corticosteroids. A French multicentre prospective cohort study

International audiencePurposeSevere Pneumocystis jirovecii pneumonia (PJP) requiring intensive care has been the subject of few prospective studies. It is unclear whether delayed curative antibiotic therapy may impact survival in these severe forms of PJP. The impact of corticosteroid therapy combined with antibiotics is also unclear.MethodsThis multicentre, prospective observational study involving 49 adult intensive care units (ICUs) in France was designed to evaluate the severity, the clinical spectrum, and outcomes of patients with severe PJP, and to assess the association between delayed curative antibiotic treatment and adjunctive corticosteroid therapy with mortality.ResultsWe included 158 patients with PJP from September 2020 to August 2022. Their main reason for admission was acute respiratory failure (n = 150, 94.9%). 12% of them received antibiotic prophylaxis for PJP before ICU admission. The ICU, hospital, and 6-month mortality were 31.6%, 35.4%, and 40.5%, respectively. Using time-to-event analysis with a propensity score-based inverse probability of treatment weighting, the initiation of curative antibiotic treatment after 96 h of ICU admission was associated with faster occurrence of death [time ratio: 6.75; 95% confidence interval (95% CI): 1.48–30.82; P = 0.014]. The use of corticosteroids for PJP was associated with faster occurrence of death (time ratio: 2.48; 95% CI 1.01–6.08; P = 0.048).ConclusionThis study showed that few patients with PJP admitted to intensive care received prophylactic antibiotic therapy, that delay in curative antibiotic treatment was common and that both delay in curative antibiotic treatment and adjunctive corticosteroids for PJP were associated with accelerated mortality

Outcomes in Patients With COVID-19 With Acute Encephalopathy and Coma: An International Prospective Study

International audienceBackground and ObjectivesTo report the prevalence of acute encephalopathy and outcomes in patients with severe coronavirus disease 2019 (COVID-19) and to identify determinants of 90-day outcomes.MethodsData from adults with severe COVID-19 and acute encephalopathy were prospectively collected for patients requiring intensive care unit management in 31 university or university-affiliated intensive care units in 6 countries (France, United States, Colombia, Spain, Mexico, and Brazil) between March and September of 2020. Acute encephalopathy was defined, as recently recommended, as subsyndromal delirium or delirium or as a comatose state in case of severely decreased level of consciousness. Logistic multivariable regression was performed to identify factors associated with 90-day outcomes. A Glasgow Outcome Scale-Extended (GOS-E) score of 1-4 was considered a poor outcome (indicating death, vegetative state, or severe disability).ResultsOf 4,060 patients admitted with COVID-19, 374 (9.2%) experienced acute encephalopathy at or before the intensive care unit (ICU) admission. A total of 199/345 (57.7%) patients had a poor outcome at 90-day follow-up as evaluated by the GOS-E (29 patients were lost to follow-up). On multivariable analysis, age older than 70 years (odds ratio [OR] 4.01, 95% CI 2.25-7.15), presumed fatal comorbidity (OR 3.98, 95% CI 1.68-9.44), Glasgow coma scale score <9 before/at ICU admission (OR 2.20, 95% CI 1.22-3.98), vasopressor/inotrope support during ICU stay (OR 3.91, 95% CI 1.97-7.76), renal replacement therapy during ICU stay (OR 2.31, 95% CI 1.21-4.50), and CNS ischemic or hemorrhagic complications as acute encephalopathy etiology (OR 3.22, 95% CI 1.41-7.82) were independently associated with higher odds of poor 90-day outcome. Status epilepticus, posterior reversible encephalopathy syndrome, and reversible cerebral vasoconstriction syndrome were associated with lower odds of poor 90-day outcome (OR 0.15, 95% CI 0.03-0.83).DiscussionIn this observational study, we found a low prevalence of acute encephalopathy at ICU admission in patients with COVID-19. More than half of patients with COVID-19 presenting with acute encephalopathy had poor outcomes as evaluated by GOS-E. Determinants of poor 90-day outcome were dominated by older age, comorbidities, degree of impairment of consciousness before/at ICU admission, association with other organ failures, and acute encephalopathy etiology.Trial Registration InformationThe study is registered with ClinicalTrials.gov, number NCT04320472