Christian Martin

Bio: Christian Martin is an academic researcher from Claude Bernard University Lyon 1. The author has contributed to research in topics: Power module & Inductor. The author has an hindex of 27, co-authored 146 publications receiving 2552 citations. Previous affiliations of Christian Martin include University of Lyon & Lyon College.

Clinical features and prognostic factors of listeriosis: the MONALISA national prospective cohort study.

Abstract: Summary Background Listeriosis is a severe foodborne infection and a notifiable disease in France. We did a nationwide prospective study to characterise its clinical features and prognostic factors. Methods MONALISA was a national prospective observational cohort study. We enrolled eligible cases declared to the National Reference Center for Listeria (all microbiologically proven) between Nov 3, 2009, and July 31, 2013, in the context of mandatory reporting. The outcomes were analysis of clinical features, characterisation of Listeria isolates, and determination of predictors of 3-month mortality or persisting impairment using logistic regression. A hierarchical clustering on principal components was also done for neurological and bacteraemic cases. The study is registered at ClinicalTrials.gov, number NCT01520597. Findings We enrolled 818 cases from 372 centres, including 107 maternal–neonatal infections, 427 cases of bacteraemia, and 252 cases of neurolisteriosis. Only five (5%) of 107 pregnant women had an uneventful outcome. 26 (24%) of 107 mothers experienced fetal loss, but never after 29 weeks of gestation or beyond 2 days of admission to hospital. Neurolisteriosis presented as meningoencephalitis in 212 (84%) of 252 patients; brainstem involvement was only reported in 42 (17%) of 252 patients. 3-month mortality was higher for bacteraemia than neurolisteriosis (hazard ratio [HR] 0·54 [95% CI 0·41–0·69], p Interpretation The severity of listeriosis is higher than reported elsewhere. We found evidence of a significantly reduced survival in patients with neurolisteriosis treated with adjunctive dexamethasone, and also determined the time window for fetal losses. MONALISA provides important new data to improve management and predict outcome in listeriosis. Funding Programme Hospitalier Recherche Clinique, Institut Pasteur, Inserm, French Public Health Agency.

State of the art of high temperature power electronics

Abstract: High temperature power electronics has become possible with the recent availability of silicon carbide devices. This material, as other wide-bandgap semiconductors, can operate at temperatures above 500 °C, whereas silicon is limited to 150-200 °C. Applications such as transportation or a deep oil and gas wells drilling can benefit. A few converters operating above 200 °C have been demonstrated, but work is still ongoing to design and build a power system able to operate in harsh environment (high temperature and deep thermal cycling).

Prevalence of Vancomycin-Resistant Enterococci in Fecal Samples from Hospitalized Patients and Nonhospitalized Controls in a Cattle-Rearing Area of France

Abstract: Vancomycin-resistant enterococci (VRE) have emerged as nosocomial pathogens over the last decade, but little is known about their epidemiology. We report on the prevalence of VRE fecal colonization on the basis of a prospective study among patients hospitalized in a hematology intensive care unit and among nonhospitalized subjects living in the local community. A total of 243 rectal swabs from hematology patients and 169 stool samples from the control group were inoculated onto bile-esculin agar plates with and without 6 mg of vancomycin per liter and into an enrichment bile-esculin broth supplemented with 4 mg of vancomycin per liter. A total of 37% of the hospitalized patients and 11.8% of the subjects from the community were found to be VRE carriers. A total of 65 VRE strains were isolated: 12 (18.5%) E. faecium, 46 (70.7%) E. gallinarum, and 7 (10.8%) E. casseliflavus strains. No E. faecalis strains were detected. All the E. faecium strains were of the vanA genotype. Molecular typing by pulsed-field gel electrophoresis revealed a different pattern for each vanA VRE strain that originated from an individual subject. To our knowledge, this is the first study to be carried out in a cattle-rearing region of France. It reports a higher VRE prevalence than that reported in previous European or U.S. studies. A partial explanation is the use of an enrichment broth step which enabled detection of strains which would otherwise have been missed, but the fact that subjects and patients were recruited from a predominantly agricultural area where vancomycin-related antibiotics have recently been used in animal husbandry could also contribute to the high levels of VRE in patients and subjects alike.

Prospective study of positional nystagmus in 100 consecutive patients.

Abstract: Objectives:The purpose of this study was to investigate the various diagnoses of patients who present with positional nystagmus.Methods:Positional maneuvers were systematically performed in the plane of the posterior canal (PC; Dix-Hallpike maneuver) and the horizontal canal (HC; patients were rolled to either side in a supine position) on 490 consecutive patients essentially referred for vertigo and/or gait unsteadiness.Results:One hundred patients (20%) presented positional nystagmus. This nystagmus had a peripheral origin in 83 patients, including 80 patients with benign paroxysmal positional vertigo (BPPV). In BPPV, the PC was involved in 61 patients, the HC in 18 patients (geotropic horizontal nystagmus in 11 and ageotropic in 7; changing from geotropic to ageotropic or the reverse in 4 patients), and both the PC and HC in 1 patient. There was evidence of central positional nystagmus in 12 patients, including positional downbeat nystagmus during the Dix-Hallpike maneuver in 7 patients with various ne...

Community-associated methicillin-resistant Staphylococcus aureus: epidemiology and clinical consequences of an emerging epidemic.

Abstract: Summary: Staphylococcus aureus is an important cause of skin and soft-tissue infections (SSTIs), endovascular infections, pneumonia, septic arthritis, endocarditis, osteomyelitis, foreign-body infections, and sepsis. Methicillin-resistant S. aureus (MRSA) isolates were once confined largely to hospitals, other health care environments, and patients frequenting these facilities. Since the mid-1990s, however, there has been an explosion in the number of MRSA infections reported in populations lacking risk factors for exposure to the health care system. This increase in the incidence of MRSA infection has been associated with the recognition of new MRSA clones known as community-associated MRSA (CA-MRSA). CA-MRSA strains differ from the older, health care-associated MRSA strains; they infect a different group of patients, they cause different clinical syndromes, they differ in antimicrobial susceptibility patterns, they spread rapidly among healthy people in the community, and they frequently cause infections in health care environments as well. This review details what is known about the epidemiology of CA-MRSA strains and the clinical spectrum of infectious syndromes associated with them that ranges from a commensal state to severe, overwhelming infection. It also addresses the therapy of these infections and strategies for their prevention.

High Frequency of Hypermutable Pseudomonas aeruginosa in Cystic Fibrosis Lung Infection

Abstract: The lungs of cystic fibrosis (CF) patients are chronically infected for years by one or a few lineages of Pseudomonas aeruginosa These bacterial populations adapt to the highly compartmentalized and anatomically deteriorating lung environment of CF patients, as well as to the challenges of the immune defenses and antibiotic therapy These selective conditions are precisely those that recent theoretical studies predict for the evolution of mechanisms that augment the rate of variation Determination of spontaneous mutation rates in 128 P aeruginosa isolates from 30 CF patients revealed that 36% of the patients were colonized by a hypermutable (mutator) strain that persisted for years in most patients Mutator strains were not found in 75 non-CF patients acutely infected with P aeruginosa This investigation also reveals a link between high mutation rates in vivo and the evolution of antibiotic resistance

BTS guidelines for the management of community acquired pneumonia in adults: update 2009.

Abstract: A summary of the initial management of patients admitted to hospital with suspected community acquired pneumonia (CAP) is presented in fig 8. Tables 4 and 5, respectively, summarise (1) the relevant microbiological investigations and (2) empirical antibiotic choices recommended in patients with CAP. Figure 8 Hospital management of community acquired pneumonia (CAP) in the first 4 h. CXR, chest x ray; DBP, diastolic blood pressure; SBP, systolic blood pressure. View this table: Table 4 Recommendations for the microbiological investigation of community acquired pneumonia (CAP) View this table: Table 5 Initial empirical treatment regimens for community acquired pneumonia (CAP) in adults ### Investigations ( Section 5 ) #### When should a chest radiograph be performed in the community? 1. It is not necessary to perform a chest radiograph in patients with suspected CAP unless: 2. #### When should a chest radiograph be performed in hospital? 1. All patients admitted to hospital with suspected CAP should have a chest radiograph performed as soon as possible to confirm or refute the diagnosis. [D] The objective of any service should be for the chest radiograph to be performed in time for antibiotics to be administered within 4 h of presentation to hospital should the diagnosis of CAP be confirmed. #### When should the chest radiograph be repeated during recovery? 1. The chest radiograph need not be repeated prior to hospital discharge in those who have made a satisfactory clinical recovery from CAP. [D] 2. A chest radiograph should be arranged after about 6 weeks for all those patients who have persistence of symptoms or physical signs or who are at higher risk of underlying malignancy (especially smokers and those aged >50 years) whether or not they have been admitted to hospital. [D] 3. Further investigations which may include bronchoscopy should be considered in patients with persisting signs, symptoms …

Multi-level conversion : high voltage choppers and voltage-source inverters

Abstract: The authors discuss high-voltage power conversion. Conventional series connection and three-level voltage source inverter techniques are reviewed and compared. A novel versatile multilevel commutation cell is introduced: it is shown that this topology is safer and more simple to control, and delivers purer output waveforms. The authors show how this technique can be applied to either choppers or voltage-source inverters and generalized to any number of switches.<>