Structural Relaxation of Materials with Spin-Orbit Coupling: Analytical Forces in Spin-Current DFT

Analytical gradients of the total energy are provided for local density and generalized-gradient hybrid approximations to generalized Kohn-Sham spin-current density functional theory (SCDFT). It is shown that gradients may be determined analytically, in a two-component framework, including spin-orbit coupling (SOC), with high accuracy. We demonstrate that renormalization of the electron-electron potential by SOC-induced spin-currents can account for considerable modification of crystal structures. In the case of Iodine-based molecular crystals, the effect may amount to more than half of the total modification of the structure by SOC. Such effects necessitate an SCDFT, rather than DFT, formulation, in which exchange-correlation functionals are endowed with an explicit dependence on spin-current densities. An implementation is presented in the \textsc{Crystal} program

Mid- and Far-Infrared Marker Bands of the Metal Coordination Sites of the Histidine Side Chains in the Protein Cu,Zn-Superoxide Dismutase

International audienceVibrational spectroscopy gives important information on the properties of ligand and metal–ligand bonds in metalloenzymes. Infrared spectroscopy is appealing for the study of metal active sites that are not amenable to Raman spectroscopy. We present a combined experimental and theoretical approach to analyze the mid- and far-IR spectra of Cu,Zn-superoxide dismutase (Cu,Zn-SOD) as a probe of the histidine ligands. This metalloenzyme provides a unique model to identify specific IR signatures of metal–histidine coordination and to study their alterations as a function of the metal (copper/zinc), the copper valence state (+I/+II), the histidine coordination mode (Nτ and Nπ) and the histidine protonation state. DFT calculations combined with normal mode descriptions from potential energy distribution calculations were performed on two slightly different cluster models. Differences in the constraints at the side chain of one histidine Cu ligand sensibly modify the geometric parameters and vibrational properties. Electrochemically induced FTIR difference spectroscopy provided mid- and far-IR fingerprint spectra of the Cu protein in aqueous media that are sensitive to the redox state of the Cu centre at the active site. Comparisons of the DFT predictions with the experimental IR modes of the histidine ligands at the Cu,Zn-SOD active site showed that useful mid-IR markers of histidine Nτ and Nπ coordination were predicted with good accuracy. The DFT analysis further demonstrated a link between the ν(C4–C5) mode frequency of His46 and the specific properties of the His46–Cu bond in Cu,Zn-SOD. A combined theoretical and experimental approach on samples in H2O and 2H2O or 15N-labelled samples identified the contributions from the histidine side chain modes in the 669–629 cm–1 region

CD4+CD25+ regulatory T cells inhibit natural killer cell functions in a transforming growth factor–β–dependent manner

Tumor growth promotes the expansion of CD4+CD25+ regulatory T (T reg) cells that counteract T cell–mediated immune responses. An inverse correlation between natural killer (NK) cell activation and T reg cell expansion in tumor-bearing patients, shown here, prompted us to address the role of T reg cells in controlling innate antitumor immunity. Our experiments indicate that human T reg cells expressed membrane-bound transforming growth factor (TGF)–β, which directly inhibited NK cell effector functions and down-regulated NKG2D receptors on the NK cell surface. Adoptive transfer of wild-type T reg cells but not TGF-β−/− T reg cells into nude mice suppressed NK cell–mediated cytotoxicity, reduced NKG2D receptor expression, and accelerated the growth of tumors that are normally controlled by NK cells. Conversely, the depletion of mouse T reg cells exacerbated NK cell proliferation and cytotoxicity in vivo. Human NK cell–mediated tumor recognition could also be restored by depletion of T reg cells from tumor-infiltrating lymphocytes. These findings support a role for T reg cells in blunting the NK cell arm of the innate immune system

Savoir caractériser les complémentarités entre cultures et élevage pour accompagner la reconception des systèmes de polyculture - élevage dans leurs transitions agroécologiques

International audienceIntegrated Corp-Livestock farming systems (ICLS) should be able to maximize the implementation of agro-ecologic practices. Crops feed livestock and manure fertilize crops, which creates a virtuous circle. However, integrated crop-livestock farming systems cover a diversity of agricultural systems without consensus on how to charaterize them,. As each form of ICLS has not the same aims, they also do not have the same economic and environmental performances. To archieve obtaining situations with the expected virtuous theoretical characteristics, these systems will have to implement different changes. This is wath we describe through the experience of four experimental farms and several communications made during the symposium : "Les polycultures-élevages : valoriser leurs atouts pour la transition agroécologique" in Dijon in October 2017, as well as results from analyzes and presentations of methods and tools developed for these systems.Les systèmes de polyculture-élevage ont théoriquement les moyens de maximiser la mise en oeuvre de pratiques agroécologiques : les cultures alimentent le troupeau dont les effluents fertilisent les terres selon un cercle vertueux. Cependant, le terme « polyculture-élevage » (PCE) masque une diversité de systèmes sans l’existence d’un consensus sur la façon de la caractériser. Or, chaque forme de PCE ne va pas viser les mêmes objectifs, ni avoir les mêmes performances environnementales et économiques. Pour atteindre des situations où les caractéristiques théoriques vertueuses attendues sont obtenues, ces systèmes auront des trajectoires différentes. C’est ce que nous montrons à travers l’expérience de 4 exploitations expérimentales et de présentations faites lors du colloque « Les polycultures-élevages: valoriser leurs atouts pour la transition agroécologique » à Dijon en Octobre 2017, ainsi que de résultats d’analyses et de présentations de méthodes et outils de conseil développés pour ces systèmes

The BLLAST field experiment: Boundary-Layer late afternoon and sunset turbulence

Due to the major role of the sun in heating the earth's surface, the atmospheric planetary boundary layer over land is inherently marked by a diurnal cycle. The afternoon transition, the period of the day that connects the daytime dry convective boundary layer to the night-time stable boundary layer, still has a number of unanswered scientific questions. This phase of the diurnal cycle is challenging from both modelling and observational perspectives: it is transitory, most of the forcings are small or null and the turbulence regime changes from fully convective, close to homogeneous and isotropic, toward a more heterogeneous and intermittent state. These issues motivated the BLLAST (Boundary-Layer Late Afternoon and Sunset Turbulence) field campaign that was conducted from 14 June to 8 July 2011 in southern France, in an area of complex and heterogeneous terrain. A wide range of instrumented platforms including full-size aircraft, remotely piloted aircraft systems, remote-sensing instruments, radiosoundings, tethered balloons, surface flux stations and various meteorological towers were deployed over different surface types. The boundary layer, from the earth's surface to the free troposphere, was probed during the entire day, with a focus and intense observation periods that were conducted from midday until sunset. The BLLAST field campaign also provided an opportunity to test innovative measurement systems, such as new miniaturized sensors, and a new technique for frequent radiosoundings of the low troposphere. Twelve fair weather days displaying various meteorological conditions were extensively documented during the field experiment. The boundary-layer growth varied from one day to another depending on many contributions including stability, advection, subsidence, the state of the previous day's residual layer, as well as local, meso- or synoptic scale conditions. Ground-based measurements combined with tethered-balloon and airborne observations captured the turbulence decay from the surface throughout the whole boundary layer and documented the evolution of the turbulence characteristic length scales during the transition period. Closely integrated with the field experiment, numerical studies are now underway with a complete hierarchy of models to support the data interpretation and improve the model representations.publishedVersio

Structure sociale et structure de tâche

We have studied the interaction between the social structure of task groups formed after a sociometric investigation and the structure of the functional relations determined by an a priori logical analysis of the task. The results show that in two different tasks, only the groups where the social structure is isomorphic to the functional structure can reach the maximum theoretical performance which can be expected from the logical analysis of the task.On étudie l'interaction entre la structure sociale de groupes de travail, constitués après enquête sociométrique, et la structure des relations fonctionnelles déterminées par une analyse logique a priori de la tâche. On montre que, dans deux tâches différentes, seuls les groupes dont la structure sociale est isomorphe à la structure fonctionnelle peuvent atteindre à la performance théorique maximum prévisible à partir de l'analyse logique de la tâche.Poitou J.-P., Flament Claude. Structure sociale et structure de tâche. In: L'année psychologique. 1967 vol. 67, n°2. pp. 493-512

« Observatoire du Donon » : Diagnostic de l'impact des cervidés sur l'avenir des peuplements forestiers - Base de travail pour la gestion. (Rapport final)

[Departement_IRSTEA]Territoires [TR1_IRSTEA]SEDYVINEn raison de problèmes récurrents de régénération sur le massif forestier du Donon (75 000 ha), une structure partenariale regroupant des organismes de gestion cynégétique et sylvicole se formalise en 2006 : il y a création de l'observatoire du Donon. Après s'être intéressé à l'étude du compartiment animal, un diagnostic sylvicole est mené en 2010 pour évaluer l'impact des cervidés sur les peuplements forestiers en cours de régénération. Cette démarche pilote a été réalisée à l'échelle de l'intégralité du massif en s'affranchissant des limites administratives et foncières. Le diagnostic sylvicole repose sur le recensement exhaustif des peuplements potentiellement dégradables par les cervidés, un plan d'échantillonnage, l'inventaire des dégâts dans les peuplements de l'échantillon pour aboutir à l'analyse et l'interprétation des données statistiques. Les résultats mettent en évidence des difficultés qui affectent près de 90 % des peuplements en cours de renouvellement. Pour ces peuplements, constitués principalement de Sapin pectiné, la responsabilité directe de l'abroutissement commis par les cervidés se vérifie dans 70 % des cas. Au regard des résultats de l'avenir sylvicole des peuplements, de la connaissance des populations de Cerf sur le massif et des prélèvements des saisons passées, nous sommes en mesure de proposer des orientations de gestion pour le retour d'un équilibre sylvo-cynégétiqu

Dementias in Aged People: The Neuropathological Point of View

info:eu-repo/semantics/publishe

Distribution and expression of the alpha-tubulin mRNA in the hippocampus and the temporal cortex in Alzheimer's disease.

The distribution of the messenger RNA for alpha-tubulin has been investigated by in situ hybridization in the human hippocampus and temporal cortex in normal subjects and in Alzheimer's disease. The alpha-tubulin mRNA was strongly expressed in neurons in the gyrus dentatus, in the Ammon's horn and in cortical layers of the temporal cortex. The same distribution was observed in Alzheimer's disease. An important reduction of the hybridization signal was apparent, however, in areas rich in neurofibrillary lesions, e.g. as in layer II of entorhinal cortex. Neurons containing neurofibrillary tangles exhibited a weaker hybridization signal than adjacent neurons devoid of neurofibrillary tangles. The immunoreactivity for alpha-tubulin was drastically reduced in tangles-bearing neurons. These results indicate that tubulin transcription is reduced in tangles-bearing neurons, a reduction which might play a role in the reported decrease in the number of microtubules in neurons containing neurofibrillary tangles.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe