Steering efficiency of a ultrarelativistic proton beam in a thin bent crystal

Crystals with small thickness along the beam exhibit top performance for steering particle beams through planar channeling. For such crystals, the effect of nuclear dechanneling plays an important role because it affects their efficiency. We addressed the problem through experimental work carried out with 400 GeV/c protons at fixed-target facilities of CERN-SPS. The dependence of efficiency vs. curvature radius has been investigated and compared favourably to the results of modeling. A realistic estimate of the performance of a crystal designed for LHC energy including nuclear dechanneling has been achieved.Comment: 16 pages, 6 figure

Environmental sustainability of Alpine livestock farms

The 2006 FAO report concerning the environmental impact of the livestock sector has generated scientific debate, especially considering the context of global warming and the need to provide animal products to a growing world population. However, this sector differs widely in terms of environmental context, production targets, degree of intensification and cultural role. The traditional breeding systems in the Alps were largely based on the use of meadows and pastures and produced not only milk and meat but also other fundamental positive externalities and ecosystem services, such as conservation of genetic resources, water flow regulation, pollination, climate regulation, landscape maintenance, recreation and ecotourism and cultural heritage. In recent decades, the mountain livestock, mainly represented by dairy cattle, has been affected by a dramatic reduction of farms, a strong increase of animals per farm, an increase in indoor production systems, more extensive use of specialised non-indigenous cattle breeds and the increasing use of extra-farm concentrates instead of meadows and pastures for fodder. This paper firstly describes the livestock sector in the Italian Alps and analyses the most important factors affecting their sustainability. Secondly, it discusses the need to assess the ecosystem services offered by forage- based livestock systems in mountains with particular attention to greenhouse gas emission and its mitigation by carbon sequestration. In conclusion, comparison between the different elements of the environmental sustainability of mountain livestock systems must be based on a comprehensive overview of the relationships among animal husbandry, environment and socio-economic context

Low temperature deactivation of Ge heavily n-type doped by ion implantation and laser thermal annealing

International audienceHeavy doping of Ge is crucial for several advanced micro-and optoelectronic applications, but, at the same time, it still remains extremely challenging. Ge heavily n-type doped at a concentration of 1 X 10(20) cm(-3) by As ion implantation and melting laser thermal annealing (LTA) is shown here to be highly metastable. Upon post-LTA conventional thermal annealing As electrically deactivates already at 350 degrees C reaching an active concentration of similar to 4 x 10(19) cm(-3). No significant As diffusion is detected up to 450 degrees C, where the As activation decreases further to similar to 3 x 10(19) cm(-3). The reason for the observed detrimental deactivation was investigated by Atom Probe Tomography and in situ High Resolution X-Ray Diffraction measurements. In general, the thermal stability of heavily doped Ge layers needs to be carefully evaluated because, as shown here, deactivation might occur at very low temperatures, close to those required for low resistivity Ohmic contacting of n-type Ge

Extended point defects in crystalline materials: Ge and Si

B diffusion measurements are used to probe the basic nature of self-interstitial 'point' defects in Ge. We find two distinct self-interstitial forms - a simple one with low entropy and a complex one with entropy ~30 k at the migration saddle point. The latter dominates diffusion at high temperature. We propose that its structure is similar to that of an amorphous pocket - we name it a 'morph'. Computational modelling suggests that morphs exist in both self-interstitial and vacancy-like forms, and are crucial for diffusion and defect dynamics in Ge, Si and probably many other crystalline solids

Synthesis of Large-Area Crystalline MoS2 by Sputter Deposition and Pulsed Laser Annealing

The wafer-scale synthesis of layered transitional metal dichalcogenides presenting good crystal quality and homogeneous coverage is a challenge for the development of next-generation electronic devices. This work explores a fairly unconventional growth method based on a two-step process consisting in sputter deposition of stochiometric MoS2 on Si/SiO2 substrates followed by nanosecond UV (248 nm) pulsed laser annealing. Large-scale 2H-MoS2 multi-layer films were successfully synthetized in a N2-rich atmosphere thanks to a fine-tuning of the laser annealing parameters by varying the number of laser pulses and their energy density. The identification of the optimal process led to the success in achieving a (002)-oriented nanocrystalline MoS2 film without performing post-sulfurization. It is noteworthy that the spatial and temporal confinement of laser annealing keeps the Si/SiO2 substrate temperature well below the back-end-of-line temperature limit of Si CMOS technology (770 K). The synthesis method described here can speed up the integration of large-area 2D materials with Si-based devices, paving the way for many important applications

Pyro-electrolytic water splitting for hydrogen generation

Water splitting by thermal cycling of a pyroelectric element that acts as an external charge source offers an alternative method to produce hydrogen from transient low-grade waste heat or natural temperature changes. In contrast to conventional energy harvesting, where the optimised load resistance is used to maximise the combination of current and voltage, for water splitting applications there is a need to optimise the system to achieve a sufficiently high potential difference for water electrolysis, whilst also maintaining a high current output. For the thermal harvesting system examined here, a high impedance 0.5 M KOH electrolyte with working electrodes connected to a rectified pyroelectric harvester produced the highest voltage of 2.34 V, which was sufficient for H2 generation. In addition to electrolyte concentration, the frequency of the temperature oscillations was examined and reducing the heating-cooling frequency led to a larger change in temperature to generate increased pyroelectric charge and a higher potential difference for pyro-water splitting. Finally, in the absence of sacrificial reagents, cyclic production of H2 (0.654 μmol/h) was demonstrated for the optimised processing parameters of electrolyte and thermal cycling frequency using the external pyroelectric element as a charge source for water splitting

Enhancement of the Inelastic Nuclear Interaction Rate in Crystals via Antichanneling

The interaction rate of a charged particle beam with the atomic nuclei of a target varies significantly if the target has a crystalline structure. In particular, under specific orientations of the target with respect to the incident beam, the probability of inelastic interaction with nuclei can be enhanced with respect to the unaligned case. This effect, which can be named antichanneling, can be advantageously used in the cases where the interaction between beam and target has to be maximized. Here we propose to use antichanneling to increase the radioisotope production yield via cyclotron. A dedicated set of experimental measurements was carried out at the INFN Legnaro Laboratories with the AN2000 and CN accelerators to prove the existence of the antichanneling effect. The variation of the interaction yield at hundreds of keV to MeV energies was observed by means of sapphire and indium phosphide crystals, achieving an enhancement of the interaction rate up to 73% and 25%, respectively. Such a result may pave the way to the development of a novel type of nozzle for the existing cyclotrons, which can exploit crystalline materials as targets for radioisotope production, especially to enhance the production rate for expensive prime materials with minor upgrades of the current instrumentation

Bone regeneration with adipose derived stem cells in a rabbit model

It has been shown that stem cells are able to calcify both in vitro and in vivo once implanted under the skin, if conveniently differentiated. Nowadays, however, a study on their efficiency in osseous regeneration does not exist in scientific literature and this very task is the real aim of the present experimentation. Five different defects of 6 mm in diameter and 2 mm in depth were created in the calvaria of 8 white New Zealand rabbits. Four defects were regenerated using 2 different conveniently modified scaffolds (Bio-Oss\uae Block and Bio-Oss Collagen\uae, Geistlich), with and without the aid of stem cells. After the insertion, the part was covered with a collagen membrane fixed by 5 modified titan pins (Altapin\uae). The defect in the front was left empty on purpose as an internal control to each animal. Two animals were sacrificed respectively after 2, 4, 6, 10 weeks. The samples were evaluated with micro-CT and histological analysis. Micro-CT analysis revealed that the quantity of new bone for samples with Bio-Oss\uae Block and stem cells was higher than for samples with Bio-Oss\uae Block alone. Histological analysis showed that regeneration occurred in an optimal way in every sample treated with scaffolds. The findings indicated that the use of adult stem cells combined with scaffolds accelerated some steps in normal osseous regeneration

Immune synapse formation promotes lipid peroxidation and MHC-I upregulation in licensed dendritic cells for efficient priming of CD8+ T cells

This study was supported by the Spanish Ministry of Science and Innovation (grants PID2020-120412RB-I00, PDC2021-121797-I00, PGC2018- 097019-BI00, PID2021-122348NB-I00, PLEC2022-009235, PLEC2022- 009298, PID2021-125415OB-I00, and PID2019-105761RB-I00); Comunidad de Madrid (INTEGRAMUNE, P2022/BMD7209 and IMMUNO-VAR, P2022/BMD-7333); Ramón Areces Foundation “Ciencias de la Vida y la Salud” (XIX Concurso-2018); “la Caixa” Banking Foundation (grants HR17-00016, HR17-00247, and HR22-00253); ProteoRed from Instituto de Salud Carlos III (PT17/0019/0003- ISCIII-SGEFI / ERDF); CIBER Cardiovascular (CB16/11/00272, CB16/11/00277); Agencia Estatal de Investigación (AEI); Fondo de Investigació n Sanitaria del Instituto de Salud Carlos III; co-funding by Fondo Europeo de Desarrollo Regional (FEDER); and European Research Council Starting Grant SYNVIVO 853179. D.C.-F. is supported by an INPhINIT Retaining Fellowship from “la Caixa” Foundation (LCF/BQ/DR19/11740010). S.I. is supported by a RYC-2016- 19463 fellowship. E.H. is supported by an FPI fellowship (PRE2019- 087509). We thank Miguel Vicente-Manzanares for critically reading the manuscript. The CNIC is supported by the Instituto de Salud Carlos III (ISCIII), the Ministerio de Ciencia e Innovación (MCIN) and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (grant CEX2020-001041-S funded by MICIN/AEI/10.13039/501100011033). The QIAGEN IPA software was used to create Figs. 3a and 5a.S