Non-contact torsion transducer based on the measurement of Moire patterns using plastic optical fibres

An angular and displacement sensor that uses a polymer optical fiber and Moire patterns is demonstrated. Moire fringes are generated using two transparent superimposed planar gratings placed in front of an optical mirror. Moire patterns with periods ranging from 0.4 to 2 mm have been obtained in this way with 1mm-diameter plastic optical fibers for torsion angles ranging from 10° to 20° have been compared with theoretical calculations and a good agreement has been confirmed. Measuring the period length and the number of periods, both the relative angle between the gratings and the displacement of the fiber with respect to the mirror are obtained. With this technique very low angles can be measured with a very high resolution. The sensor principle has been successfully checked in the laboratory. Finally, the effect of employing different plastic fibers is also discussed. Besides, other possible applications of this measurement technique are presented and discussed

Alarm system of optical fibre using the thermal-optical sensibility of the PNIPAAm polymer

An alarm system as extrinsic sensor on optical fibers for detecting and controlling inflammable liquids based on thermosensitive proprieties of the PNIPAAm hydrogel is presented. The changes on the optical proprieties of the PNIPAAm with the temperature (being its LCST 32ºC), induce abrupt changes on the light intensity and they act as an alarm signal, which is transmitted by optical fibers and after they will be processed by an optoelectronic circuit, responsible to active an alarm. An appropriate system consists of the hydrogel connected between its ends to two segments of plastic optical fibers (source and receiver) and they turn on the alarm when a photo detector does not receive light when the hydrogel becomes when it reaches threshold of temperature. The characterization of the hydrogel and the experimental results are presented for a prototype

Alarm system of optical fibre using the thermal-optical sensibility of the hydrogel PNIPAAm

RESUMEN: Se presenta un sistema sensor extrínseco de fibras ópticas para detectar y controlar líquidos inflamables basadas en las propiedades termo-ópticas del hidrogel PNIPAAm. Los cambios en propiedades ópticas del PNIPAAm con la temperatura (a 32ºC) inducen cambios abruptos en la intensidad de la luz propagada y actúan como una señal, que transmitidos por fibras ópticas y procesados por una unidad opto-electrónica pueden activar un sistema de alarma. Un dispositivo apropiado contiene el hidrogel que es conectado a un extremo de un trozo de fibra óptica de plástico (emisora y receptora). Cuando la temperatura del medio exterior al PNIPAAm supera los 32ºC, este deviene opaco y genera una señal transmitida al fotodetector y la unidad opto-electrónica asociada acciona una alarma. La caracterización del hidrogel y los resultados experimentales de un prototipo son presentadas.ABSTRACT: An alarm system as extrinsic sensor on optical fibers for detecting and controlling inflammable liquids based on thermosensitive proprieties of the PNIPAAm hydrogel is presented. The changes on the optical proprieties of the PNIPAAm with the temperature (being its LCST 32ºC), induce abrupt changes on the light intensity and they act as an alarm signal, which is transmitted by optical fibers and after they will be processed by an optoelectronic circuit, responsible to active an alarm. An appropriate system consists of the hydrogel connected a segment of plastic optical fiber (source and receiver) and they turn on the alarm when a photo detector does not receive light when the hydrogel becomes when it reaches threshold of temperature. The characterization of the hydrogel and the experimental results are presented for a prototype

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

Conception, validation et mise en oeuvre d’une architecture de stockage de données de très haute capacité basée sur le principe de la photographie Lippmann

Nowadays, the holographic data storage presents a renewed interest. It seems well placed to lead a new generation of optical storage capacity and playback speeds much higher than current optical discs based on the recording onto a surface. In this thesis, we propose a new architecture for optical data storage that is based on the principle of Lippmann photography interferential. Information are included in the volume of the recording material in the form of pages of data multiplexing in wavelength by exploiting the Bragg selectivity. This technique, although very similar to holography, had never been considered for high storage capacities. The aim of the thesis was to analyze this new architecture to determine the conditions that can lead to very high capacities. This analysis was based on a numerical simulation tool of diffraction process involved in this memory interferential. It allowed us to define two conditions under which these high capacities are achievable. In accordance with these conditions, we developed a demonstrator called "Lippmann’s memory" and have thus demonstrated experimentally that the capacity is proportional to the thickness of the recording material. With such an architecture, Terabyte disks of 12 cm in diameter are expected.Le stockage de données par holographie suscite un intérêt renouvelé. Il semble bien placé pour conduire à une nouvelle génération de mémoires optiques aux capacités et débits de lecture bien supérieurs à ceux des disques optiques actuels basés sur l’enregistrement dit surfacique. Dans ce travail de thèse, nous proposons une nouvelle architecture de stockage optique de données qui s’inspire du principe de la photographie interférentielle de Lippmann. Les informations y sont inscrites dans le volume du matériau d’enregistrement sous la forme de pages de données par multiplexage en longueur d’onde en exploitant la sélectivité de Bragg. Cette technique, bien que très voisine de l’holographie, n’avait jamais été envisagée pour le stockage à hautes capacités. L’objectif de la thèse a été d’analyser cette nouvelle architecture afin de déterminer les conditions pouvant conduire à de très hautes capacités. Cette analyse s’est appuyée sur un outil de simulation numérique des processus de diffraction en jeu dans cette mémoire interférentielle. Elle nous a permis de définir deux conditions sous lesquelles ces hautes capacités sont atteignables. En respectant ces conditions, nous avons conçu un démonstrateur de mémoire dit de « Lippmann » et avons ainsi démontré expérimentalement que la capacité est bien proportionnelle à l’épaisseur du matériau d’enregistrement. Avec une telle architecture, des capacités de l’ordre du Téraoctet sont attendues pour des disques de 12 cm de diamètre

Conception, validation and implementation of a new architecture of high capacity optical storage based on Lippmann's photography

Le stockage de données par holographie suscite un intérêt renouvelé. Il semble bien placé pour conduire à une nouvelle génération de mémoires optiques aux capacités et débits de lecture bien supérieurs à ceux des disques optiques actuels basés sur l’enregistrement dit surfacique. Dans ce travail de thèse, nous proposons une nouvelle architecture de stockage optique de données qui s’inspire du principe de la photographie interférentielle de Lippmann. Les informations y sont inscrites dans le volume du matériau d’enregistrement sous la forme de pages de données par multiplexage en longueur d’onde en exploitant la sélectivité de Bragg. Cette technique, bien que très voisine de l’holographie, n’avait jamais été envisagée pour le stockage à hautes capacités. L’objectif de la thèse a été d’analyser cette nouvelle architecture afin de déterminer les conditions pouvant conduire à de très hautes capacités. Cette analyse s’est appuyée sur un outil de simulation numérique des processus de diffraction en jeu dans cette mémoire interférentielle. Elle nous a permis de définir deux conditions sous lesquelles ces hautes capacités sont atteignables. En respectant ces conditions, nous avons conçu un démonstrateur de mémoire dit de « Lippmann » et avons ainsi démontré expérimentalement que la capacité est bien proportionnelle à l’épaisseur du matériau d’enregistrement. Avec une telle architecture, des capacités de l’ordre du Téraoctet sont attendues pour des disques de 12 cm de diamètre.Nowadays, the holographic data storage presents a renewed interest. It seems well placed to lead a new generation of optical storage capacity and playback speeds much higher than current optical discs based on the recording onto a surface. In this thesis, we propose a new architecture for optical data storage that is based on the principle of Lippmann photography interferential. Information are included in the volume of the recording material in the form of pages of data multiplexing in wavelength by exploiting the Bragg selectivity. This technique, although very similar to holography, had never been considered for high storage capacities. The aim of the thesis was to analyze this new architecture to determine the conditions that can lead to very high capacities. This analysis was based on a numerical simulation tool of diffraction process involved in this memory interferential. It allowed us to define two conditions under which these high capacities are achievable. In accordance with these conditions, we developed a demonstrator called "Lippmann’s memory" and have thus demonstrated experimentally that the capacity is proportional to the thickness of the recording material. With such an architecture, Terabyte disks of 12 cm in diameter are expected

Conception, validation et mise en oeuvre d'une architecture de stockage de données de très haute capacité basée sur le principe de la photographie Lippmann

Le stockage de données par holographie suscite un intérêt renouvelé. Il semble bien placé pour conduire à une nouvelle génération de mémoires optiques aux capacités et débits de lecture bien supérieurs à ceux des disques optiques actuels basés sur l enregistrement dit surfacique. Dans ce travail de thèse, nous proposons une nouvelle architecture de stockage optique de données qui s inspire du principe de la photographie interférentielle de Lippmann. Les informations y sont inscrites dans le volume du matériau d enregistrement sous la forme de pages de données par multiplexage en longueur d onde en exploitant la sélectivité de Bragg. Cette technique, bien que très voisine de l holographie, n avait jamais été envisagée pour le stockage à hautes capacités. L objectif de la thèse a été d analyser cette nouvelle architecture afin de déterminer les conditions pouvant conduire à de très hautes capacités. Cette analyse s est appuyée sur un outil de simulation numérique des processus de diffraction en jeu dans cette mémoire interférentielle. Elle nous a permis de définir deux conditions sous lesquelles ces hautes capacités sont atteignables. En respectant ces conditions, nous avons conçu un démonstrateur de mémoire dit de Lippmann et avons ainsi démontré expérimentalement que la capacité est bien proportionnelle à l épaisseur du matériau d enregistrement. Avec une telle architecture, des capacités de l ordre du Téraoctet sont attendues pour des disques de 12 cm de diamètre.Nowadays, the holographic data storage presents a renewed interest. It seems well placed to lead a new generation of optical storage capacity and playback speeds much higher than current optical discs based on the recording onto a surface. In this thesis, we propose a new architecture for optical data storage that is based on the principle of Lippmann photography interferential. Information are included in the volume of the recording material in the form of pages of data multiplexing in wavelength by exploiting the Bragg selectivity. This technique, although very similar to holography, had never been considered for high storage capacities. The aim of the thesis was to analyze this new architecture to determine the conditions that can lead to very high capacities. This analysis was based on a numerical simulation tool of diffraction process involved in this memory interferential. It allowed us to define two conditions under which these high capacities are achievable. In accordance with these conditions, we developed a demonstrator called "Lippmann s memory" and have thus demonstrated experimentally that the capacity is proportional to the thickness of the recording material. With such an architecture, Terabyte disks of 12 cm in diameter are expected.PARIS11-SCD-Bib. électronique (914719901) / SudocSudocFranceF

Characterization of new thermo-responsive hydrogels for optical sensing applications

We report the use of new hydrogels based on poly-N-isopropylacrilamide and MeOXA in order to measure temperature using optical transmittance. We have obtained thermo-responsive hydrogels based on the radical copolymerization of N-isopropylacrylamide (NIPAAm) and bis-macromonomers of 2-methyl-2-oxazoline (MeOXA). The hydrogels show conformational transitions at defined temperatures, which are a function of the molar ratio NIPAAm / MeOXA inside of the hydrogel. The temperatures of transition have been determined by means of 1H NMR spectroscopy and by turbidity measurements using an optical setup with optical fibers and a diode laser. We show the first experimental results and we discuss some future applications such as an optical switch or a device for optical sensing

Temperature fiber optic sensor using a thermosensible hydrogel

Nowdays, polymers like hydrogels that respond to well defined stimuli, have a particular interest in fields like optoelectronics, biotechnology, materials, etc. One of this polymers is the NIPAAM, that posses thermo optics properties. This work is oriented to the design and implementation of a temperature sensor using fiber optics and having as sensitive part a sintetized hydrogel of polyNIPAAM and MeOXA of reversible thermosensible characteristics. For this setup we use a glass ampoule which is coupled to two pieces of plastic, inside the ampoule it is placed the hydrogel. The working principle relies in the turbidity changes in a well known temperature called critical. We present the experimental results of the designed and implemented device