33 research outputs found
Transmission measurement at 10.6 microns of Te2As3Se5 rib-waveguides on As2S3 substrate
The feasibility of chalcogenide rib waveguides working at lambda = 10.6
microns has been demonstrated. The waveguides comprised a several microns thick
Te2As3Se5 film deposited by thermal evaporation on a polished As2S3 glass
substrate and further etched by physical etching in Ar or CF4/O2 atmosphere.
Output images at 10.6 microns and some propagation losses roughly estimated at
10dB/cm proved that the obtained structures behaved as channel waveguides with
a good lateral confinement of the light. The work opens the doors to the
realisation of components able to work in the mid and thermal infrared up to 20
microns and even more.Comment: The following article appeared in Vigreux-Bercovici et al., Appl.
Phys. Lett. 90, 011110 (2007) and may be found at
http://link.aip.org/link/?apl/90/01111
Technology challenges for space interferometry: the option of mid-infrared integrated optics
Nulling interferometry is a technique providing high angular resolution which
is the core of the space missions Darwin and the Terrestrail Planet Finder. The
first objective is to reach a deep degree of starlight cancelation in the range
6 -- 20 microns, in order to observe and to characterize the signal from an
Earth-like planet. Among the numerous technological challenges involved in
these missions, the question of the beam combination and wavefront filtering
has an important place. A single-mode integrated optics (IO) beam combiner
could support both the functions of filtering and the interferometric
combination, simplifying the instrumental design. Such a perspective has been
explored in this work within the project Integrated Optics for Darwin (IODA),
which aims at developing a first IO combiner in the mid-infrared. The solutions
reviewed here to manufacture the combiner are based on infrared dielectric
materials on one side, and on metallic conductive waveguides on the other side.
With this work, additional inputs are offered to pursue the investigation on
mid-infrared photonics devices.Comment: Accepted in Adv. in Space Researc
Intradialytic Nutrition and Hemodialysis Prescriptions: A Personalized Stepwise Approach
Dialysis and nutrition are two sides of the same coinâdialysis depurates metabolic waste that is typically produced by food intake. Hence, dietetic restrictions are commonly imposed in order to limit potassium and phosphate and avoid fluid overload. Conversely, malnutrition is a major challenge and, albeit to differing degrees, all nutritional markers are associated with survival. Dialysis-related malnutrition has a multifactorial origin related to uremic syndrome and comorbidities but also to dialysis treatment. Both an insufficient dialysis dose and excessive removal are contributing factors. It is thus not surprising that dialysis alone, without proper nutritional management, often fails to be effective in combatting malnutrition. While composite indexes can be used to identify patients with poor prognosis, none is fully satisfactory, and the definitions of malnutrition and protein energy wasting are still controversial. Furthermore, most nutritional markers and interventions were assessed in hemodialysis patients, while hemodiafiltration and peritoneal dialysis have been less extensively studied. The significant loss of albumin in these two dialysis modalities makes it extremely difficult to interpret common markers and scores. Despite these problems, hemodialysis sessions represent a valuable opportunity to monitor nutritional status and prescribe nutritional interventions, and several approaches have been tried. In this concept paper, we review the current evidence on intradialytic nutrition and propose an algorithm for adapting nutritional interventions to individual patients
Ready to change: Attitudes of an elderly CKD stage 3–5 population towards testing protein-free food
DNA damage in B and T lymphocytes of farmers during one pesticide spraying season
Purpose The effect of one pesticide spraying seasonon DNA damage was measured on B and T lymphocytesamong open-field farmers and controls.Methods At least two peripheral blood samples were collectedfrom each individual: one in a period without anypesticide application, several weeks after the last use (January,at period P0), and another in the intensive pesticidespraying period (May or June, at period P4). DNA damagewas studied by alkaline comet assay on isolated B or Tlymphocytes.Results Longitudinal comparison of DNA damageobserved at both P0 and P4 periods revealed a statisticallysignificant genotoxic effect of the pesticide spraying seasonin both B (P = 0.02) and T lymphocytes (P = 0.02) in exposed farmers. In contrast, non-farmers did not showany significant modifications. DNA damage levels in Band T lymphocytes were significantly higher in farmersthan in non-farmers during the P4 period (P = 0.003 andP = 0.001 for B and T lymphocytes, respectively) but notduring the P0 period. The seasonal effect observed amongfarmers was not correlated with either total farm area, farmarea devoted to crops or recent solar exposure. On average,farmers used pesticides for 21 days between P0 and P4.Between the two time points studied, there was a tendencyfor a potential effect of the number of days of fungicidetreatments (r2 = 0.43; P = 0.11) on T lymphocyte DNAdamage.Conclusions A genotoxic effect was found in lymphocytesof farmers exposed to pesticides, suggesting in particularthe possible implication of fungicides
In-doped gallium oxide micro- and nanostructures: morphology, structure, and luminescence properties
The influence of indium doping on morphology, structural, and luminescence properties of gallium oxide micro- and nanostructures is reported. Indium-doped gallium oxide micro- and nanostructures have been grown by thermal oxidation of metallic gallium in the presence of indium oxide. The dominant morphologies are beltlike structures, which in many cases are twisted leading to springlike structures, showing that In diffusion in Ga2O3 influences the microstructure shapes. High-resolution transmission electron microscopy has revealed the presence of twins in the belts, and energy-dispersive X-ray spectroscopy in the scanning electron microscopy (SEM) has detected a segregation of indium impurities at the edges of planar structures. These results suggest that indium plays a major role in the observed morphologies and support the assumption of a layer by layer model as growth mechanism. An additional assessment of indium influence on the defect structure has been performed by cathodoluminescence in the SEM, X-ray photoelectron microscopy, and spatially resolved Raman spectroscopy
Guides dâonde canaux Ă base de couches chalcogĂ©nures dĂ©posĂ©es par co-Ă©vaporation thermique et gravĂ©es par voie sĂšche pour des applications en optique intĂ©grĂ©e infrarouge
Les verres de chalcogĂ©nure sont des matĂ©riaux particuliĂšrement prometteurs pour lâoptique
intégrée dans le domaine infrarouge du fait de leur transparence exceptionnelle dans cette
gamme de longueurs dâonde. Un des objectifs de notre Ă©quipe MontpelliĂ©raine est de
démontrer la faisabilité de micro-composants IR par empilement et gravure de couches
Ă©paisses de verres de chalcogĂ©nure, et de les valoriser au travers dâapplications telles
que la mĂ©trologie de lâenvironnement ou lâinterfĂ©romĂ©trie spatiale. Dans le cadre dâun
projet financĂ© par LâAgence Spatiale EuropĂ©enne et pilotĂ© par Thales Alenia Space, nous
travaillons actuellement sur la rĂ©alisation de guides dâonde canaux Ă base de couches
épaisses Te-Ge. Dans cet article nous décrivons les principales phases de leur fabrication
: dĂ©pĂŽt par coĂ©vaporation thermique â mĂ©thode jamais utilisĂ©e jusquâalors pour les
matĂ©riaux chalcogĂ©nures â et modification gĂ©omĂ©trique par voie sĂšche sous plasma
réactif
Anomalous metallic lithium phases:âIdentification by ESR, ENDOR, and the bistable Overhauser effect
International audienc
Effects of acceptor and donor additives on the properties of MgTiO3 ceramics sintered under reducing atmosphere
International audienc