Diamond formation from C60 crystals heated under high pressure

X-ray Diffraction (XRD) and Raman Microspectroscopy showed that diamond is detected when solid C60 crystals are heated above 1600°C, in the 9-15 GP range. These samples are here studied by High Resolution Transmission Electron Microscopy (HRTEM) in order to allow the structural characteristics of more or less organised co-existing carbon phases

[(18)F]Fluoroethyltyrosine- positron emission tomography-guided radiotherapy for high-grade glioma

BACKGROUND: To compare morphological gross tumor volumes (GTVs), defined as pre- and postoperative gadolinium enhancement on T1-weighted magnetic resonance imaging to biological tumor volumes (BTVs), defined by the uptake of (18)F fluoroethyltyrosine (FET) for the radiotherapy planning of high-grade glioma, using a dedicated positron emission tomography (PET)-CT scanner equipped with three triangulation lasers for patient positioning. METHODS: Nineteen patients with malignant glioma were included into a prospective protocol using FET PET-CT for radiotherapy planning. To be eligible, patients had to present with residual disease after surgery. Planning was performed using the clinical target volume (CTV = GTV union or logical sum BTV) and planning target volume (PTV = CTV + 20 mm). First, the interrater reliability for BTV delineation was assessed among three observers. Second, the BTV and GTV were quantified and compared. Finally, the geometrical relationships between GTV and BTV were assessed. RESULTS: Interrater agreement for BTV delineation was excellent (intraclass correlation coefficient 0.9). Although, BTVs and GTVs were not significantly different (p = 0.9), CTVs (mean 57.8 +/- 30.4 cm(3)) were significantly larger than BTVs (mean 42.1 +/- 24.4 cm(3); p < 0.01) or GTVs (mean 38.7 +/- 25.7 cm(3); p < 0.01). In 13 (68%) and 6 (32%) of 19 patients, FET uptake extended >or= 10 and 20 mm from the margin of the gadolinium enhancement. CONCLUSION: Using FET, the interrater reliability had excellent agreement for BTV delineation. With FET PET-CT planning, the size and geometrical location of GTVs and BTVs differed in a majority of patients

Microelectronics-Based Biosensors Dedicated to the Detection of Neurotransmitters: A Review

Dysregulation of neurotransmitters (NTs) in the human body are related to diseases such as Parkinson's and Alzheimer's. The mechanisms of several neurological disorders, such as epilepsy, have been linked to NTs. Because the number of diagnosed cases is increasing, the diagnosis and treatment of such diseases are important. To detect biomolecules including NTs, microtechnology, micro and nanoelectronics have become popular in the form of the miniaturization of medical and clinical devices. They offer high-performance features in terms of sensitivity, as well as low-background noise. In this paper, we review various devices and circuit techniques used for monitoring NTs in vitro and in vivo and compare various methods described in recent publications

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Quelques propriétés mathématiques d'un modèle de flammes sphériques avec pertes de chaleur

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Le gisement paléontologique et préhistorique de la rivière souterraine de Padirac (affluent R. de Joly), commune de Miers (Lot, France) : principaux résultats de l'expédition «Padirac 1985»

In 1983, an important paleontological and prehistoric site was discovered in the karst system of Padirac (Lot, France). This paper gives the main consequences of the second scientific expedition in this cave (10 days running underground). The fauna is various and numerous. It seems to indicate a rissian age but the radiocarbon results do not correspond to this hypothesis, perhaps because of the addition of more recent bones. Stone tools give evidence of a Mousterian of the Acheulian Tradition. The genesis of the deposit is explained by the carriage of bones and prehistoric stones in the course of the successive risings of the underground river.En 1983 était découvert un important gisement paléontologique et préhistorique dans le réseau karstique de Padirac (Lot, France). La présente note donne les principaux résultats de la seconde expédition scientifique dans cette cavité (10 jours consécutifs sous terre). La faune est abondante et diversifiée. Elle semble dater du Riss mais les résultats obtenus par le radiocarbone ne concordent pas avec cette hypothèse, peut-être à cause d'un mélange d'éléments plus récents. L'industrie lithique témoigne d'une culture moustérienne de tradition acheuléenne. La genèse du gisement peut s'expliquer par l'apport d'ossements et d'objets pré-historiques lors des crues successives de la rivière souterraine.Philippe Michel, Jaubert Jacques, Rouzaud François. Le gisement paléontologique et préhistorique de la rivière souterraine de Padirac (affluent R. de Joly), commune de Miers (Lot, France) : principaux résultats de l'expédition «Padirac 1985». In: Bulletin mensuel de la Société linnéenne de Lyon, 55ᵉ année, n°8, octobre 1986. pp. 265-280

Numerical simulation of a point-source initiated flame ball with heat losses

This article is devoted to the numerical study of a flame ball model, derived by Joulin, which obeys to a singular integro-differential equation. The numerical scheme that we analyze here, is based upon a one step method, and we are interested in its long-time behaviour. We recover the same dynamics as in the continuous case: quenching, or stabilization of the flame, depending on heat losses, and an energy input parameter

Contexte géomorphologique et formation du gisement

Rouzaud François, Fabriol Jean-François, Philippe Michel. Contexte géomorphologique et formation du gisement. In: Nouvelles archives du Muséum d'histoire naturelle de Lyon, tome 31, 1994. L'autre Padirac. Spéléologie, karstologie, paléontologie et préhistoire, dans l'affluent Robert de Joly. pp. 80-98

Atlas-guided generation of pseudo-CT images for MRI-only and hybrid PET–MRI-guided radiotherapy treatment planning

Magnetic resonance imaging (MRI)-guided attenuation correction (AC) of positron emission tomography (PET) data and/or radiation therapy (RT) treatment planning is challenged by the lack of a direct link between MRI voxel intensities and electron density. Therefore, even if this is not a trivial task, a pseudo-computed tomography (CT) image must be predicted from MRI alone. In this work, we propose a two-step (segmentation and fusion) atlas-based algorithm focusing on bone tissue identification to create a pseudo-CT image from conventional MRI sequences and evaluate its performance against the conventional MRI segmentation technique and a recently proposed multi-atlas approach. The clinical studies consisted of pelvic CT, PET and MRI scans of 12 patients with loco-regionally advanced rectal disease. In the first step, bone segmentation of the target image is optimized through local weighted atlas voting. The obtained bone map is then used to assess the quality of deformed atlases to perform voxel-wise weighted atlas fusion. To evaluate the performance of the method, a leave-one-out cross-validation (LOOCV) scheme was devised to find optimal parameters for the model. Geometric evaluation of the produced pseudo-CT images and quantitative analysis of the accuracy of PET AC were performed. Moreover, a dosimetric evaluation of volumetric modulated arc therapy photon treatment plans calculated using the different pseudo-CT images was carried out and compared to those produced using CT images serving as references. The pseudo-CT images produced using the proposed method exhibit bone identification accuracy of 0.89 based on the Dice similarity metric compared to 0.75 achieved by the other atlas-based method. The superior bone extraction resulted in a mean standard uptake value bias of -1.5 +/- 5.0% (mean +/- SD) in bony structures compared to -19.9 +/- 11.8% and -8.1 +/- 8.2% achieved by MRI segmentation-based (water-only) and atlas-guided AC. Dosimetric evaluation using dose volume histograms and the average difference between minimum/maximum absorbed doses revealed a mean error of less than 1% for the both target volumes and organs at risk. Two-dimensional (2D) gamma analysis of the isocenter dose distributions at 1%/1 mm criterion revealed pass rates of 91.40 +/- 7.56%, 96.00 +/- 4.11% and 97.67 +/- 3.6% for MRI segmentation, atlas-guided and the proposed methods, respectively. The proposed method generates accurate pseudo-CT images from conventional Dixon MRI sequences with improved bone extraction accuracy. The approach is promising for potential use in PET AC and MRI-only or hybrid PET/MRI-guided RT treatment planning