2,459 research outputs found
Medical information prior to invasive medical procedures in otorhinolaryngology–head and neck surgery in France
SummaryBased on a review of the medical literature (PubMed database, keywords: medical information, informed consent), the authors analyse the main medicolegal aspects concerning the patient information that must be provided in France prior to any invasive diagnostic or therapeutic medical procedures in otorhinolaryngology head and neck surgery, as well as the patient's perception and recall of the information provided, the quality of the information provided and problems encountered in providing this information. In the light of this review, several solutions are recommended to improve this essential phase prior to obtaining the patient's informed consent
Optical performance of the JWST MIRI flight model: characterization of the point spread function at high-resolution
The Mid Infra Red Instrument (MIRI) is one of the four instruments onboard
the James Webb Space Telescope (JWST), providing imaging, coronagraphy and
spectroscopy over the 5-28 microns band. To verify the optical performance of
the instrument, extensive tests were performed at CEA on the flight model (FM)
of the Mid-InfraRed IMager (MIRIM) at cryogenic temperatures and in the
infrared. This paper reports on the point spread function (PSF) measurements at
5.6 microns, the shortest operating wavelength for imaging. At 5.6 microns the
PSF is not Nyquist-sampled, so we use am original technique that combines a
microscanning measurement strategy with a deconvolution algorithm to obtain an
over-resolved MIRIM PSF. The microscanning consists in a sub-pixel scan of a
point source on the focal plane. A data inversion method is used to reconstruct
PSF images that are over-resolved by a factor of 7 compared to the native
resolution of MIRI. We show that the FWHM of the high-resolution PSFs were
5-10% wider than that obtained with Zemax simulations. The main cause was
identified as an out-of-specification tilt of the M4 mirror. After correction,
two additional test campaigns were carried out, and we show that the shape of
the PSF is conform to expectations. The FWHM of the PSFs are 0.18-0.20 arcsec,
in agreement with simulations. 56.1-59.2% of the total encircled energy
(normalized to a 5 arcsec radius) is contained within the first dark Airy ring,
over the whole field of view. At longer wavelengths (7.7-25.5 microns), this
percentage is 57-68%. MIRIM is thus compliant with the optical quality
requirements. This characterization of the MIRIM PSF, as well as the
deconvolution method presented here, are of particular importance, not only for
the verification of the optical quality and the MIRI calibration, but also for
scientific applications.Comment: 13 pages, submitted to SPIE Proceedings vol. 7731, Space Telescopes
and Instrumentation 2010: Optical, Infrared, and Millimeter Wav
The warm interstellar medium around the Cygnus Loop
Observations of the oxygen lines [OII]3729 and [OIII]5007 in the medium
immediately beyond the Cygnus Loop supernova remnant were carried out with the
scanning Fabry-P\'erot spectrophotometer ESOP. Both lines were detected in
three different directions - east, northeast and southwest - and up to a
distance of 15 pc from the shock front. The ionized medium is in the immediate
vicinity of the remnant, as evinced by the smooth brightening of both lines as
the adiabatic shock transition (defined by the X-ray perimeter) is crossed.
These lines are usually brighter around the Cygnus Loop than in the general
background in directions where the galactic latitude is above 5 degrees. There
is also marginal (but significant) evidence that the degree of ionization is
somewhat larger around the Cygnus Loop. We conclude that the energy necessary
to ionize this large bubble of gas could have been supplied by an O8 or O9 type
progenitor or the particles heated by the expanding shock front. The second
possibility, though highly atractive, would have to be assessed by extensive
modelling.Comment: 18 pages, 8 figures, ApJ 512 in pres
Ternary combination of irinotecan, fluorouracil-folinic acid and oxaliplatin: results on human colon cancer cell lines
A marked antitumour efficacy is currently obtained by oxaliplatin (LOHP)–fluorouracil (FU)–folinic acid (FA) combination and by CPT11–FU–FA combination. Logically, the triple association LOHP, CPT11 and FUFA will be soon tested in cancer patients. The aim of the present study was to compare two schedules combining SN38 (the active metabolite of CPT11, irinotecan) with FU–FA and LOHP. The two schedules differed by the SN38 position. The relative contribution of each drug in the resulting global cytotoxicity was evaluated. Two human colon cancer cell lines were used (WIDR and SW620 both p53 mutated). LOHP plus FA were applied for 2 h, just before a 48 h FU exposure. The SN38 sequence was applied for 24 h, starting either 48 h before LOHP-FA (schedule A), or just after LOHP-FA exposure (schedule B). Cytotoxicity was assessed by the 3-(4,5-demethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) test and drug interactions were analysed according to the Chou and Talalay method, based on the computation of a combination index (CI). The SN38 position significantly induces a shift from additivity-antagonism when SN38 was applied after LOHP, towards additivity-synergism when SN38 was applied first (P = 0.03). The relative contribution (RC) of each drug in the overall cytotoxicity of the triple combination was defined as the drug concentration giving 50% cell lethality (IC 50) of the double association without that drug divided by the IC 50 of the triple association. Whatever the SN38 position, the larger contribution was made by LOHP (median RC = 2.4) and the smaller by SN38 (median RC = 1.1). In addition, the contribution of FUFA was improved when SN38 was applied first (median RC = 2.2) as compared to the opposite schedule (median RC = 1.2). Results were in agreement between the two explored cell lines. The present data should be taken into account when establishing the rationale of future trials combining CPT11, LOHP and FU–FA. © 2001 Cancer Research Campaign http://www.bjcancer.co
The Mid-Infrared Instrument for the James Webb Space Telescope, V: Predicted Performance of the MIRI Coronagraphs
The imaging channel on the Mid-Infrared Instrument (MIRI) is equipped with
four coronagraphs that provide high contrast imaging capabilities for studying
faint point sources and extended emission that would otherwise be overwhelmed
by a bright point-source in its vicinity. Such bright sources might include
stars that are orbited by exoplanets and circumstellar material, mass-loss
envelopes around post-main-sequence stars, the near-nuclear environments in
active galaxies, and the host galaxies of distant quasars. This paper describes
the coronagraphic observing modes of MIRI, as well as performance estimates
based on measurements of the MIRI flight model during cryo-vacuum testing. A
brief outline of coronagraphic operations is also provided. Finally, simulated
MIRI coronagraphic observations of a few astronomical targets are presented for
illustration
Impact of thymidine phosphorylase surexpression on fluoropyrimidine activity and on tumour angiogenesis
Tumoral thymidine phosphorylase (TP) appears to play a dual role by being involved in neoangiogenesis and by activating 5FU prodrugs at the tumoral target site. The aim of the study was to investigate more thoroughly these potential physiological and pharmacological roles of TP. A rat carcinoma cell line (PROb) was transfected with TP/PD-ECGF in order to study the effect of the overexpression of this enzyme (1) on the sensitivity of cells to 5′DFUR and 5FU in vitro and (2) on tumour growth in vivo by using a syngenic tumour model in the BDIX rat (hepatic tumours, sub-cutaneous tumours). Cytotoxic effects of 5′DFUR, and to a lesser extent those of 5FU, were enhanced in TP clones as compared to control cells: there was a highly significant correlation between TP activity and in vitro sensitivity to 5’DFUR (r2= 0.91, P = 0.0002, n = 8) and, to a lesser extent, to 5FU (r2= 0.49, P = 0.053, n = 8). The impact of TP transfection on tumour growth was relatively modest and concerned only the initial stages of tumour expansion. Staining of TP tumours for endothelial (factor VIII) cells was always higher than controls. The staining ratio (TP/controls) tended to be reduced as tumours increased in size. The stability of TP expression was checked both in vitro (TP activity measurement) and in vivo (RT-PCR determinations) and there was no loss of TP expression over time which could be advanced to explain the progressive weakening of the impact of TP overexpression on both tumour growth and neoangiogenesis. © 2001 Cancer Research Campaign http://www.bjcancer.co
Anisotropic colloids through non-trivial buckling
We present a study on buckling of colloidal particles, including
experimental, theoretical and numerical developments. Oil-filled thin shells
prepared by emulsion templating show buckling in mixtures of water and ethanol,
due to dissolution of the core in the external medium. This leads to
conformations with a single depression, either axisymmetric or polygonal
depending on the geometrical features of the shells. These conformations could
be theoretically and/or numerically reproduced in a model of homogeneous
spherical thin shells with bending and stretching elasticity, submitted to an
isotropic external pressure.Comment: submitted to EPJ
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Key Performance Criteria Affecting the Most the Safety of a Nuclear Waste Long Term Storage : A Case Study Commissioned by CEA
As part of the work scope set in the French law on high level long lived waste R&D passed in 1991, CEA is conducting a research program to establish the scientific basis and assess the feasibility of long term storage as an option for the safe management of nuclear waste for periods as long as centuries. This goal is a significant departure from the current industrial practice where storage facilities are usually built to last only a few decades. From a technical viewpoint such an extension in time seems feasible provided care and maintenance is exercised. Considering such long periods of time, the risk for Society of loosing oversight and control of such a facility is real, which triggers the question of whether and how long term storage safety can be actually achieved. Therefore CEA commissioned a study (1) in which MUTADIS Consultants (2) and CEPN (3) were both involved. The case study looks into several past and actual human enterprises conducted over significant periods o f time, one of them dating back to the end of the 18th century, and all identified out of the nuclear field. Then-prevailing societal behavior and organizational structures are screened out to show how they were or are still able to cope with similar oversight and control goals. As a result, the study group formulated a set of performance criteria relating to issues like responsibility, securing funds, legal and legislative implications, economic sustainable development, all being areas which are not traditionally considered as far as technical studies are concerned. These criteria can be most useful from the design stage onward, first in an attempt to define the facility construction and operating guiding principles, and thereafter to substantiate the safety case for long term storage and get geared to the public dialogue on that undertaking should it become a reality
The Mid-Infrared Instrument for the James Webb Space Telescope, III: MIRIM, The MIRI Imager
In this article, we describe the MIRI Imager module (MIRIM), which provides
broad-band imaging in the 5 - 27 microns wavelength range for the James Webb
Space Telescope. The imager has a 0"11 pixel scale and a total unobstructed
view of 74"x113". The remainder of its nominal 113"x113" field is occupied by
the coronagraphs and the low resolution spectrometer. We present the instrument
optical and mechanical design. We show that the test data, as measured during
the test campaigns undertaken at CEA-Saclay, at the Rutherford Appleton
Laboratory, and at the NASA Goddard Space Flight Center, indicate that the
instrument complies with its design requirements and goals. We also discuss the
operational requirements (multiple dithers and exposures) needed for optimal
scientific utilization of the MIRIM.Comment: 29 pages, 9 figure
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