113 research outputs found
Lattice softening effects at the Mott critical point of Cr-doped VO
We have performed sound velocity measurements in (VCr)O
in the vicinity of the critical point of the first order Mott transition line.
The pressure sweeps at constant temperature reveal a large dip in the
compression modulus, this dip sharpens as the critical point is approached. We
do not observe signs of criticality on the shear modulus which is
consistent with a transition governed by a scalar order parameter, in
accordance with the DMFT description of the transition. However, the amplitude
of the effect is an order of magnitude smaller than the one obtained from DMFT
calculations for a single band Hubbard model. We analyze our results using a
simple model with the electronic response function obtained from the scaling
relations for the conductivity
Les unités médico-psychiatriques : les soins partagés en santé mentale
Cet article dĂ©crit le fonctionnement dâune unitĂ© hospitaliĂšre originale, couplant approche somatique et psychiatrique sous rubrique gĂ©nĂ©rique dâune UnitĂ© MĂ©dico-Psycho-Sociale (UMPS) implantĂ©e au sein du CHU dâAngers depuis 1996. Nous proposons dâexaminer lâintĂ©rĂȘt de cette mixitĂ©, tout en interrogeant ses limites et ses difficultĂ©s de fonctionnement. LâintĂ©rĂȘt de la structure est de proposer une approche pluridisciplinaire, somatique et psychiatrique dans un mĂȘme lieu de soins. Cette double compĂ©tence de la part des personnels mĂ©dicaux et paramĂ©dicaux est nĂ©cessaire lorsque les avis ponctuels de la consultation-liaison ne suffisent plus et lors de situations complexes, dans lesquelles le double savoir-faire est sollicitĂ©, en lien avec les ressources dâune rĂ©animation et des services de spĂ©cialitĂ©s mĂ©dicales et chirurgicales. Ce type dâunitĂ©, fondĂ©e sur un fonctionnement mixte et Ă binĂŽme confirmĂ© est peu reprĂ©sentĂ©, tant en France quâĂ lâĂ©tranger. La frĂ©quence de la co-morbiditĂ© somatique et organique conduit pourtant Ă les considĂ©rer comme une rĂ©ponse innovante aux difficultĂ©s rencontrĂ©es dans ces prises en charge. Nous dĂ©crivons deux cas cliniques afin dâargumenter notre propos
Reduced Cancer Incidence in Huntington's Disease: Analysis in the Registry Study
BACKGROUND: People with Huntington\u27s disease (HD) have been observed to have lower rates of cancers.
OBJECTIVE: To investigate the relationship between age of onset of HD, CAG repeat length, and cancer diagnosis.
METHODS: Data were obtained from the European Huntington\u27s disease network REGISTRY study for 6540 subjects. Population cancer incidence was ascertained from the GLOBOCAN database to obtain standardised incidence ratios of cancers in the REGISTRY subjects.
RESULTS: 173/6528 HD REGISTRY subjects had had a cancer diagnosis. The age-standardised incidence rate of all cancers in the REGISTRY HD population was 0.26 (CI 0.22-0.30). Individual cancers showed a lower age-standardised incidence rate compared with the control population with prostate and colorectal cancers showing the lowest rates. There was no effect of CAG length on the likelihood of cancer, but a cancer diagnosis within the last year was associated with a greatly increased rate of HD onset (Hazard Ratio 18.94, pâ<â0.001).
CONCLUSIONS: Cancer is less common than expected in the HD population, confirming previous reports. However, this does not appear to be related to CAG length in HTT. A recent diagnosis of cancer increases the risk of HD onset at any age, likely due to increased investigation following a cancer diagnosis
Medical-psychiatric units: shared care in mental health
This paper describes a highly unusual hospital unit that combines somatic and psychiatric approaches under the generic heading of a Medico-Psycho-Social Unit (MPSU) established at Angers University Hospital since 1996. The paper examines the value of a mixed approach while highlighting its limitations. The interest of the MPSU is that it provides a multidisciplinary, somatic and psychiatric approach on the same site. The joint expertise of medical and paramedical staff is required in cases where the assessment of the consultation-liaison services is not sufficient and in complex situations requiring the resources of an intensive care unit and specific medical and surgical specialties. Based on an established partnership and joint service provision, this type of unit is relatively uncommon both in France and abroad. However, the prevalence of somatic and organic comorbidity suggests that MPSUs are an innovative solution for the challenges of this type of care. Two clinical cases will be used as examples
Antifouling activity of novel polyisoprene-based coatings made from photocurable natural rubber derived oligomers
Natural rubber is a renewable resource with a potential as precursor of a very wide range of novel
polymers, including polyisoprene-based surfaces with antifouling (AF) activity. In this work, new ionic
and non-ionic coatings were prepared by the photocrosslinking reaction of photosensitive cis-1,4-
oligoisoprenes, bearing a variable number of ammonium groups. The photochemical crosslinking was
achieved using radical (via acrylate groups) or cationic (via epoxy groups) processes. Surface properties
of these coatings were studied by static contact angle measurements and AFM imaging. Assessment of
bioactivity demonstrated that most of the resulting coatings showed AF potential against fouling organisms:
growth inhibition of marine bacteria (Pseudoalteromonas elyakovii, Shewanella putrefaciens, Cobetia
marina, Polaribacter irgensii, Vibrio aestuarianus) and fungi (Halosphaeriopsis mediosetigera, Asteromyces
cruciatus, Lulworthia uniseptata, Zalerion sp., Monodictys pelagica); decreased adhesion of microalgae
(Navicula jeffreyi, Cylindrotheca closterium, Chlorarachnion globosum, Pleurochrysis roscoffensis, Exanthemachrysis
gayraliae, Amphora coffeaeformis); inhibition of attachment and/or germination of spores
of Ulva intestinalis. The best AF activity was obtained with the ionic surfaces. These new coatings prepared
from precursors obtained from natural rubber are in essence active by contact. As the biocidal
functions are fixed covalently to the polymer chain, detectable release of biocidal products in the marine
ecosystem is prevented so that a valuable environment-friendly alternative for new AF coatings is hereby
proposed
Fast-charging high-energy lithium-ion batteries via implantation of amorphous silicon nanolayer in edge-plane activated graphite anodes
As fast-charging lithium-ion batteries turn into increasingly important components in forthcoming applications, various strategies have been devoted to the development of high-rate anodes. However, despite vigorous efforts, the low initial Coulombic efficiency and poor volumetric energy density with insufficient electrode conditions remain critical challenges that have to be addressed. Herein, we demonstrate a hybrid anode via incorporation of a uniformly implanted amorphous silicon nanolayer and edge-site-activated graphite. This architecture succeeds in improving lithium ion transport and minimizing initial capacity losses even with increase in energy density. As a result, the hybrid anode exhibits an exceptional initial Coulombic efficiency (93.8%) and predominant fast-charging behavior with industrial electrode conditions. As a result, a full-cell demonstrates a higher energy density (>= 1060 Wh l(-1)) without any trace of lithium plating at a harsh charging current density (10.2 mA cm(-2)) and 1.5 times faster charging than that of conventional graphite
Functionalized Poly(3-hexylthiophene)s via LithiumâBromine Exchange
Poly(3-hexylthiophene) (P3HT) is one of the most extensively investigated conjugated polymers and has been employed as the active material in many devices including field-effect transistors, organic photovoltaics and sensors. As a result, methods to further tune the properties of P3HT are desirable for specific applications. Herein, we report a facile postpolymerization modification strategy to functionalize the 4-position of commercially available P3HT in two simple stepsâbromination of the 4-position of P3HT (BrâP3HT) followed by lithiumâbromine exchange and quenching with an electrophile. We achieved near quantitative lithiumâbromine exchange with BrâP3HT, which requires over 100 thienyl lithiates to be present on a single polymer chain. The lithiated-P3HT is readily combined with functional electrophiles, resulting in P3HT derivatives with ketones, secondary alcohols, trimethylsilyl (TMS) group, fluorine, or an azide at the 4-position. We demonstrated that the azide-modified P3HT could undergo Cu-catalyzed or Cu-free click chemistry, significantly expanding the complexity of the structures that can be appended to P3HT using this method.National Science Foundation (U.S.) (ECCS-0939514
Artificial Intelligence to Detect Papilledema from Ocular Fundus Photographs.
BACKGROUND: Nonophthalmologist physicians do not confidently perform direct ophthalmoscopy. The use of artificial intelligence to detect papilledema and other optic-disk abnormalities from fundus photographs has not been well studied. METHODS: We trained, validated, and externally tested a deep-learning system to classify optic disks as being normal or having papilledema or other abnormalities from 15,846 retrospectively collected ocular fundus photographs that had been obtained with pharmacologic pupillary dilation and various digital cameras in persons from multiple ethnic populations. Of these photographs, 14,341 from 19 sites in 11 countries were used for training and validation, and 1505 photographs from 5 other sites were used for external testing. Performance at classifying the optic-disk appearance was evaluated by calculating the area under the receiver-operating-characteristic curve (AUC), sensitivity, and specificity, as compared with a reference standard of clinical diagnoses by neuro-ophthalmologists. RESULTS: The training and validation data sets from 6779 patients included 14,341 photographs: 9156 of normal disks, 2148 of disks with papilledema, and 3037 of disks with other abnormalities. The percentage classified as being normal ranged across sites from 9.8 to 100%; the percentage classified as having papilledema ranged across sites from zero to 59.5%. In the validation set, the system discriminated disks with papilledema from normal disks and disks with nonpapilledema abnormalities with an AUC of 0.99 (95% confidence interval [CI], 0.98 to 0.99) and normal from abnormal disks with an AUC of 0.99 (95% CI, 0.99 to 0.99). In the external-testing data set of 1505 photographs, the system had an AUC for the detection of papilledema of 0.96 (95% CI, 0.95 to 0.97), a sensitivity of 96.4% (95% CI, 93.9 to 98.3), and a specificity of 84.7% (95% CI, 82.3 to 87.1). CONCLUSIONS: A deep-learning system using fundus photographs with pharmacologically dilated pupils differentiated among optic disks with papilledema, normal disks, and disks with nonpapilledema abnormalities. (Funded by the Singapore National Medical Research Council and the SingHealth Duke-NUS Ophthalmology and Visual Sciences Academic Clinical Program.)
Effect of Temperature Gradient Direction in the Catalyst Nanoparticle on CNTs Growth Mode
To improve the understanding on CNT growth modes, the various processes, including thermal CVD, MP-CVD and ECR-CVD, have been used to deposit CNTs on nanoporous SBA-15 and Si wafer substrates with C2H2 and H2 as reaction gases. The experiments to vary process parameter of ÎT, defined as the vector quantities of temperature at catalyst top minus it at catalyst bottom, were carried out to demonstrate its effect on the CNT growth mode. The TEM and TGA analyses were used to characterize their growth modes and carbon yields of the processes. The results show that ÎT can be used to monitor the temperature gradient direction across the catalyst nanoparticle during the growth stage of CNTs. The results also indicate that the tip-growth CNTs, base-growth CNTs and onion-like carbon are generally fabricated under conditions of ÎT > 0, <0 and ~0, respectively. Our proposed growth mechanisms can be successfully adopted to explain why the base- and tip-growth CNTs are common in thermal CVD and plasma-enhanced CVD processes, respectively. Furthermore, our experiments have also successfully demonstrated the possibility to vary ÎT to obtain the desired growth mode of CNTs by thermal or plasma-enhanced CVD systems for different applications
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