Collisional excitation of doubly and triply deuterated ammonia ND2_2H and ND3_3 by H2_2

The availability of collisional rate coefficients is a prerequisite for an accurate interpretation of astrophysical observations, since the observed media often harbour densities where molecules are populated under non--LTE conditions. In the current study, we present calculations of rate coefficients suitable to describe the various spin isomers of multiply deuterated ammonia, namely the ND$_2$H and ND$_3$ isotopologues. These calculations are based on the most accurate NH$_3$--H$_2$ potential energy surface available, which has been modified to describe the geometrical changes induced by the nuclear substitutions. The dynamical calculations are performed within the close--coupling formalism and are carried out in order to provide rate coefficients up to a temperature of $T$ = 50K. For the various isotopologues/symmetries, we provide rate coefficients for the energy levels below $\sim$ 100 cm$^{-1}$. Subsequently, these new rate coefficients are used in astrophysical models aimed at reproducing the NH$_2$D, ND$_2$H and ND$_3$ observations previously reported towards the prestellar cores B1b and 16293E. We thus update the estimates of the corresponding column densities and find a reasonable agreement with the previous models. In particular, the ortho--to--para ratios of NH$_2$D and NHD$_2$ are found to be consistent with the statistical ratios

T-cell Apoptosis in Human Glioblastoma Multiforme: Implications for Immunotherapy

We used immunohistochemistry and flow cytometry to assess apoptosis in human glioblastoma multiforme (GBM). Our immunohistochemical study revealed apoptosis of glioma cells expressing glial fibrillary acidic protein and of CD3+ T cells infiltrating GBM. To quantify and phenotype the apoptotic T cells, we performed flow cytometry on lymphocytes separated from GBM. The cells were stained with annexin-V-FLUOS/propidium iodide to identify apoptosis. We found that high proportions of both the CD4+ and CD8+ T cells were apoptotic. In particular, we found that T cells expressing Fas ligand (Fas-L, CD95L) were eight times more vulnerable to apoptosis than those not expressing Fas-L, which suggests that the T-cell apoptosis is induced by overactivation of the T-cell receptor, possibly in the absence of appropriate costimulation. Our results have implications for the design of immunotherapies for GBM

Modelling the molecular composition and nuclear-spin chemistryof collapsing pre-stellar sources★

We study the gravitational collapse of pre-stellar sources and the associated evolution of their chemical composition. We use the University of Grenoble Alpes Astrochemical Network (UGAN), which includes reactions involving the different nuclear-spin states of H2, H+3 , and of the hydrides of carbon, nitrogen, oxygen, and sulphur, for reactions involving up to seven protons. In addition, species-to-species rate coefficients are provided for the ortho/para interconversion of the H +3 + H2 system and isotopic variants. The composition of the medium is followed from an initial steady state through the early phase of isothermal gravitational collapse. Both the freeze-out of the molecules on to grains and the coagulation of the grains were incorporated in the model. The predicted abundances and column densities of the spin isomers of ammonia and its deuterated forms are compared with those measured recently towards the pre-stellar cores H-MM1, L16293E, and Barnard B1. We find that gas-phase processes alone account satisfactorily for the observations, without recourse to grain-surface reactions. In particular, our model reproduces both the isotopologue abundance ratios and the ortho:para ratios of NH2D and NHD2 within observational uncertainties. More accurate observations are necessary to distinguish between full scrambling processes – as assumed in our gas-phase network – and direct nucleus- or atom-exchange reactions

Mapping the potential use of endectocide-treated cattle to reduce malaria transmission

Treating cattle with endectocide is a longstanding veterinary practice to reduce the load of endo and ectoparasites, but has the potential to be added to the malaria control and elimination toolbox, as it also kills malaria mosquitoes feeding on the animals. Here we used openly available data to map the areas of the African continent where high malaria prevalence in 2-10 year old children coincides with a high density of cattle and high density of the partly zoophilic malaria vector Anopheles arabiensis. That is, mapping the areas where treating cattle with endectocide would potentially have the greatest impact on reducing malaria transmission. In regions of Africa that are not dominated by rainforest nor desert, the map shows a scatter of areas in several countries where this intervention shows potential, including central and eastern sub-Saharan Africa. The savanna region underneath the Sahel in West Africa appears as the climatic block that would benefit to the largest extent from this intervention, encompassing several countries. West Africa currently presents the highest under-10 malaria prevalence and elimination within the next twenty years cannot be contemplated there with currently available interventions alone, making the use of endectocide treated cattle as a complementary intervention highly appealing

Laser structuring and functionalization of nanoscaled battery materials

Possible laser processes in battery manufacturing are quite diverse regarding the control of electrochemical characteristics: LIPSS on current collector surfaces are used to adjust the adhesion of composite electrodes to current collectors, laser surface patterning turns ceramic-coated separator materials into superwicking with regard to electrolyte wetting properties, and laser structuring of composite thick film electrodes is applied to generate 3D electrode architectures with shortened lithium-ion diffusion pathways. In the field of cathode thick film development, secondary particles with nanoscaled primary particles are used and ultrafast laser ablation is applied to pattern the composite electrodes to optimize the lithium ion diffusion kinetics by enlarging the active material surface with a view to reducing cell polarization, which develops at high battery power. This enables high energy batteries to be upgraded for operation at high power. In the field of anode development for electromotive vehicles, efforts are being made to develop silicon anodes in order to significantly increase the energy density. In addition, the issue of fast charging, mainly influenced by the anode architecture, is a major topic in research and industrial development. Silicon nanoparticles are used and combined with graphite particles in a binder matrix. The large volume change as a result of the lithiation of silicon during battery operation requires laser structuring of the composite electrodes in order to counteract mechanical degradation. Analogous to cathode materials, the lithium diffusion kinetics for anodes are also significantly enhanced by the applied 3D battery concept. The impact of laser structuring and modification of battery materials on the electrochemical performance with respect to the nanoscale is of considerable relevance for future applications in battery manufacturing

Kinematically complete experimental study of Compton scattering at helium atoms near the ionization threshold

Compton scattering is one of the fundamental interaction processes of light with matter. Already upon its discovery [1] it was described as a billiard-type collision of a photon kicking a quasi-free electron. With decreasing photon energy, the maximum possible momentum transfer becomes so small that the corresponding energy falls below the binding energy of the electron. Then ionization by Compton scattering becomes an intriguing quantum phenomenon. Here we report a kinematically complete experiment on Compton scattering at helium atoms below that threshold. We determine the momentum correlations of the electron, the recoiling ion, and the scattered photon in a coincidence experiment finding that electrons are not only emitted in the direction of the momentum transfer, but that there is a second peak of ejection to the backward direction. This finding links Compton scattering to processes as ionization by ultrashort optical pulses [2], electron impact ionization [3,4], ion impact ionization [5,6], and neutron scattering [7] where similar momentum patterns occur.Comment: 7 pages, 4 figure