543 research outputs found
Synthesis and Characterization of Highly Crystalline Vertically Aligned WSe2 Nanosheets
Here, we report on the synthesis of tungsten diselenide (WSe2) nanosheets using an atmospheric pressure chemical vapor deposition technique via the rapid selenization of thin tungsten films. The morphology and the structure, as well as the optical properties, of the so-produced material have been studied using electron microscopies, X-ray photoelectron spectroscopy, photoluminescence, UV–visible and Raman spectroscopies, and X-ray diffraction. These studies confirmed the high crystallinity, quality, purity, and orientation of the WSe2 nanosheets, in addition to the unexpected presence of mixed phases, instead of only the most thermodynamically stable 2H phase. The synthesized material might be useful for applications such as gas sensing or for hydrogen evolution reaction catalysis
IFN-gamma mediates the rejection of haematopoietic stem cells in IFN-gammaR1-deficient hosts.
International audienceBACKGROUND: Interferon-gamma receptor 1 (IFN-gammaR1) deficiency is a life-threatening inherited disorder, conferring predisposition to mycobacterial diseases. Haematopoietic stem cell transplantation (HSCT) is the only curative treatment available, but is hampered by a very high rate of graft rejection, even with intra-familial HLA-identical transplants. This high rejection rate is not seen in any other congenital disorders and remains unexplained. We studied the underlying mechanism in a mouse model of HSCT for IFN-gammaR1 deficiency. METHODS AND FINDINGS: We demonstrated that HSCT with cells from a syngenic C57BL/6 Ifngr1+/+ donor engrafted well and restored anti-mycobacterial immunity in naive, non-infected C57BL/6 Ifngr1-/- recipients. However, Ifngr1-/- mice previously infected with Mycobacterium bovis bacillus Calmette-Guérin (BCG) rejected HSCT. Like infected IFN-gammaR1-deficient humans, infected Ifngr1-/- mice displayed very high serum IFN-gamma levels before HSCT. The administration of a recombinant IFN-gamma-expressing AAV vector to Ifngr1-/- naive recipients also resulted in HSCT graft rejection. Transplantation was successful in Ifngr1-/- x Ifng-/- double-mutant mice, even after BCG infection. Finally, efficient antibody-mediated IFN-gamma depletion in infected Ifngr1-/- mice in vivo allowed subsequent engraftment. CONCLUSIONS: High serum IFN-gamma concentration is both necessary and sufficient for graft rejection in IFN-gammaR1-deficient mice, inhibiting the development of heterologous, IFN-gammaR1-expressing, haematopoietic cell lineages. These results confirm that IFN-gamma is an anti-haematopoietic cytokine in vivo. They also pave the way for HSCT management in IFN-gammaR1-deficient patients through IFN-gamma depletion from the blood. They further raise the possibility that depleting IFN-gamma may improve engraftment in other settings, such as HSCT from a haplo-identical or unrelated donor
Fruit phenology of citruses, mangoes and papayas influences egg-laying preferences of Bactrocera invadens (Diptera: Tephritidae)
Introduction. African fruit production, as well as regional and international fruit trade, have experienced heavy economic losses over the past decade due to the damage caused by fruit flies, especially B. invadens Drew Tsuruta & White (Tephritidae: Diptera). Bactrocera invadens attacks fruits belonging to numerous botanical families, several of which are of great economic importance. The females of these flies generally lay their eggs in mature fruits, but some can lay in green-immature fruits. Materials and methods. The influence of the species, variety and phenology of fruits on the fruit attractiveness to B. invadens and the elicitation of B. invadens egg-laying behaviour were studied in the laboratory. Fruits harvested regularly during the years 2008 and 2009 from orchards in the Niayes area (Senegal) were exposed to gravid females in cages set for the different factors tested. The exposed fruits were then incubated and the pupae emerging from them were counted. Results and discussion. Bactrocera invadens females laid eggs in ripe fruits. Within the same fruit species, the variety plays an important role in egg-laying preference. Hence, among the mango varieties tested, the Pêche variety hosted the highest number of pupae per fruit, while the Palmer variety hosted the lowest number. Comparison among different fruit species showed that mature papaya was more infested than mature mango or citrus. Furthermore, flies were unable to develop on lime. Conclusion. Our study showed that B. invadens can infest green and ripe host fruits, and even immature abscised fruits. Consequently, management of this pest must include preventive measures in the development and implementation of an integrated management system. (Résumé d'auteur
Role of Grasslands and Grassland Management for Biogeochemical Cycles and Biodiversity. Setting up Long-Term Manipulation Experiments in France
Land use for grassland is recognised to have some beneficial effects for biodiversity and the environment: (i) regulation of the water cycle and protection of soils against erosion, (ii) accumulation of organic matter in soil and sequestration of atmospheric C, (iii) regulation of the N cycle and attenuation of the risk for N leaching, (iv) recycling of nutrients and improvement of soil quality, (v) improvement of biodiversity of vegetation, soil microbes and micro- and meso-fauna. All these effects depend upon the management of the grassland: cutting vs. grazing, stocking density, level of N inputs. Management decisions often result from short- term objectives, whereas the soil-vegetation interactions are long-term processes. Therefore, a steady state is usually not reached, which makes it difficult to determine the overall environmental effects of changes in land use and in grassland management
Frequent EGFR Positivity and Overexpression in High-Grade Areas of Human MPNSTs
Malignant peripheral nerve sheath tumours (MPNSTs) are highly malignant and resistant. Transformation might implicate up regulation of epidermal growth factor receptor (EGFR). Fifty-two MPNST samples were studied for EGFR, Ki-67, p53, and survivin expression by immunohistochemistry and for EGFR amplification by in situ hybridization. Results were correlated with clinical data. EGFR RNA was also quantified by RT-PCR in 20 other MPNSTs and 14 dermal neurofibromas. Half of the patients had a neurofibromatosis type 1 (NF1). EGFR expression, detected in 86% of MPNSTs, was more frequent in NF1 specimens and closely associated with high-grade and p53-positive areas. MPNSTs expressed more EGFR transcripts than neurofibromas. No amplification of EGFR locus was observed. NF1 status was the only prognostic factor in multivariate analysis, with median survivals of 18 and 43 months for patients with or without NF1. Finally, EGFR might become a new target for MPNSTs treatment, especially in NF1-associated MPNSTs
Rectal cancer with synchronous unresectable metastases: arguments for therapeutic choice
Environ 4 000 patients sont pris en charge chaque année en
France pour un cancer du rectum avec des métastases synchrones
jugées non résécables en réunion de concertation pluridisciplinaire
(RCP). Il n’existe pas de consensus sur la stratégie
thérapeutique à proposer et parmi les trois options possibles, les
critères de choix restent relativement imprécis.
– La chirurgie première est certes le meilleur traitement pour
contrôler les symptômes rectaux mais elle n’a pas démontré
qu’elle augmentait la survie et la résécabilité secondaire des
métastases par rapport aux autres options et comporte un
risque de résection incomplète, de complications pouvant
retarder ou empêcher la chimiothérapie, de progression accélérée
de la maladie métastatique et de mortalité comprise
entre 1 et 5 %.
– La radio-chimiothérapie première suivie d’une chirurgie permet
le contrôle des symptômes rectaux mais retarde la chimiothérapie
pour les métastases qui dominent le pronostic ; elle
expose aux mêmes risques de complications que la chirurgie
première.
– La chimiothérapie première nous paraît intéressante en
absence de complications locales sévères (occlusion, hémorragie)
; elle est potentiellement efficace sur les métastases à
distance qui conditionnent le pronostic et sur la tumeur primitive
qui répond souvent de manière similaire ; elle ne fige pas
la stratégie et offre la possibilité de l’adapter à chaque évaluation
selon la réponse, la tolérance et les possibilités de résection
(tumeur primitive et métastases).
Dans tous les cas, il est fondamental de discuter ces dossiers au
cas par cas en RCP pour adapter la stratégie thérapeutique aux
caractéristiques du patient, de la tumeur primitive et de l’extension
métastatique, ainsi qu’à la réponse obtenue aux traitements
proposés successivement.Rectal cancers with synchronous unresectable metastases are
diagnosed in about 4 000 patients. There is yet no consensus on
the therapeutic strategy for these cases which must be discussed
during multidisciplinary meeting. Three options are available
and arguments of choice remain relatively weak.
– First-line resection of the primary rectal tumour is indeed
the best treatment to control rectal symptoms but it does
not seem to improve survival and secondary resectability
of metastases when compared to other options; moreover
incomplete resection or complications may delay chemotherapy, accelerate the metastastic process and mortality
rate ranges from 1 to 5%.
– First-line radio-chemotherapy followed by surgery allows for
controlling rectal symptoms but delays chemotherapy for
metastases dominating the prognosis; it exposes the patients
to the same morbidity and mortality as first-line surgery.
– First-line chemotherapy is the third valid option in the absence
of major rectal symptoms (occlusion, haemorrhage); chemotherapy
is potentially efficient on distant metastases bearing a
high prognosis impact and on the primary rectal tumour, which
often has a similar response. First-line chemotherapy allows
for adapting the therapeutic strategy after each evaluation
according to the tumour response, side effects and possibility
of resection (primary rectal tumour and metastases).
In all cases, medical records of such patients should be discussed
during a multidisciplinary meeting to adapt the therapeutic
strategy to the patient’s characteristics, primary rectal tumor,
metastases staging and evolution
In-pile loop irradiation studies of organic coolant materials : progress report, October 1, 1963 - December 31, 1964,
Statement of responsibility on title page reads: Report prepared by: E. A. Mason, Project Supervisor; Contributors: W.N. Bley, J.C. Kim, T.H. Timmins, J.F. Terrien, A.H. Swan"Issued: February 1, 1965.""AEC Research and Development Report"--Cover"MIT-334-12."Includes bibliographical references (leaves 21-22)Progress report; October 1, 1963 - December 31, 1964M.I.T. Project no. DSR 9819U.S. Atomic Energy Commission, Savannah River Operations Office contract no. AT(38-1)-33
Is rare cancer care organized at national health system level? Multiple case study in six EU countries
Background: As a system of European Reference Networks (ERNs) emerges, we aimed to shed light on the processes through which reference centres (RCs) for rare cancers are embedded in national health systems, and to formulate hypotheses about which national care models favour equitable access for patients. Methods We used a multiple-case-study design based on the experiences of Czechia, Finland, France, Italy, Lithuania and Spain. Using sarcoma as an example of rare cancer, 52 semi-structured interviews were conducted during six on-site visits. Results The comparative analysis showed substantial heterogeneity in the processes for formalising RCs status and in their levels of integration in the different health systems, but two models, namely, the centre-based and the network-based, can be envisaged at national level. RCs for rare cancers were legally established only in France and Spain. Expert clinicians cooperate in a structured way, using network mechanisms, in France and Italy, and these countries, plus Finland and Lithuania, had a referral system to facilitate patients' access from non-expert centres to RCs. Comparative analysis of the cases enabled the identification of key healthcare planning principles in instituting RCs at the national level, among them the need to stipulate the involvement of expert professionals in steering the rare cancer care system
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