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Sizable pools of freely circulating glycosyltransferases are in blood, but understanding their physiologic contributions has been hampered because functional sources of sugar donor substrates needed to drive extracellular glycosylation have not been identified. The blood-borne ST6Gal-1 produced and secreted by the liver is the most noted among the circulatory glycosyltransferases, and decorates marrow hematopoietic progenitor cells with α2,6-linked sialic acids and restricts blood cell production. Platelets, upon activation, secrete a plethora of bioactive molecules including pro- and anti-inflammatory mediators. Cargos of sugar donor substrates for glycosyltransferase activity have also been reported in platelets. Here, we implemented a cell-based system to interrogate platelets for their ability to deliver effectively the sugar donor substrate for extracellular ST6Gal-1 to function. We report that thrombin-activated platelets, at physiologic concentration and pH, can efficiently and effectively substitute for CMP-sialic acid in extracellular ST6Gal-1-mediated sialylation of target cell surfaces. Activated platelets can also supply the sialic acid donor to sialylate the synthetic acceptor, Gal(β1,4)GlcNAcα-o-benzyl, with the product Sia(α2,6)Gal(β1,4)GlcNAcα-o-benzyl structurally confirmed confirmed by LC/MS. Platelet-secreted donor substrate was recovered in the 100,000 x g sediment, strongly suggesting the association of this otherwise soluble substrate, putatively CMP-sialic acid, within platelet microparticles. Sequestration within microparticles may facilitate delivery of glycosylation substrate at effective dosages to sites of extracellular glycosylation while minimizing excessive dilution. [ABSTRACT FROM AUTHOR]

Abstract: Most of spherical blisters formed by deuterium (D) bombardment (38eV/D) up to 3×1024 D/m2 at 300K on polycrystalline tungsten are fully elastic deformations. This has been proven by opening individual blisters with a focused ion beam and in situ observation of their complete relaxation by scanning electron microscopy. The D2 gas filling is confirmed by observing simultaneously the D2 puff. The gas pressure is causal for the stability of such spherical blisters after implantation and the gas release leads to sudden relaxation. The dilatation of the blister cap by trapped D can be excluded as cause for the blisters. [Copyright &y& Elsevier]

We performed a systematic study of the deuterium retention in the tungsten heavy alloy W-2Ni-1Fe (HPM 1850 from HC Starck, Germany). Consisting of two different phases with generally two distinctly different heats of solution, such alloys represent a special class of materials with respect to hydrogen isotope transport and retention. Deuterium was implanted from a plasma with an energy of 38 eV D−1 at sample temperatures of 100 °C, 175 °C, and 250 °C in the fluence range 1023 D m−2 to 4 × 1025 D m−2. For each combination of implantation temperature and fluence, two alloy samples were exposed together with one sample of bulk hot-rolled tungsten (from Plansee SE). The amount of retained deuterium was determined by thermal desorption with heating up to 850 °C for the alloy and 1050 °C for the bulk tungsten. The outgassed deuterium was detected by mass spectroscopy at the mass channels 3, 4, 19, and 20 corresponding to HD, D2, HDO, and D2O, respectively. The near-surface deuterium concentration was determined by 3He nuclear reaction analysis. The retention in the alloy as compared to the bulk tungsten decreases systematically with increasing implantation fluence for each of the investigated implantation temperatures. For the higher fluences the ratio decreases systematically also, as a function of implantation temperature. This means that especially for high implantation fluences and temperatures the alloy HPM 1850 systematically retains less hydrogen isotopes than bulk tungsten. This property represents an important qualification criterion as a plasma-facing material for a future fusion reactor. [ABSTRACT FROM AUTHOR]

The cross section for the combined 2D(15N,p)16N and 2D(15N,nγ)16O nuclear reactions of deuterium (2D) with incident 15N ions is evaluated and found to increase by two orders of magnitude between 3.3 and 7.0 MeV. Detecting the γ-rays at 6.1 and 7.1 MeV from these reactions allows quantifying the depth-integrated 2D content in materials in parallel with nanometer-resolved quantitative hydrogen (1H) depth profiling in surface layers through resonant 1H(15N,αγ)12C nuclear reaction analysis (NRA) using 15N ion beams. The information depth and sensitivity of 15N-2D NRA is estimated through energy loss simulations of the 15N projectiles in the analyzed material. Good agreement of the integral 2D quantitation through 2D(15N,p)16N and 2D(15N,nγ)16O NRA with 2D depth profiles obtained independently via 2D(3He,p)4He NRA is demonstrated at the example of 2D plasma-exposed tungsten samples. The simultaneous quantitation of 2D and depth-resolved 1H profiling with a single 15N ion beam promises application potential to investigate hydrogen-isotope exchange and diffusion processes in surface and thin buried layers. [ABSTRACT FROM AUTHOR]

Even though tungsten (W) is considered to be the most favored plasma-facing material (PFM) for nuclear fusion reactors thanks to its beneficial physical properties, its advantage for those plasma-facing components to be subjected to medium heat flux and high neutron irradiation dose is compromised by unfavorable nuclear behavior such as intermediate-level radioactive waste activation and embrittlement caused by lattice damage and transmutation. Chromium (Cr) or Cr-based materials may have the potential to mitigate these shortcomings while maintaining acceptable thermal and physical performances required for PFM. They could offer attractive design options, particularly for those parts where the particle fluxes are relatively low and the heat flux is not too high (≤ 5 MW/m²) while nuclear loads are high (≥ 5 dpa). In this article, we report the first results of a preliminary technology feasibility study for an engineered Cr-based material fabricated based on a powder-metallurgical route. To explore an optimal metallurgical condition ensuring reasonable mechanical properties and low deuterium retention, a novel two-phase Cr-W composite was developed via current-assisted rapid sintering at low sintering temperature. The composite showed a cell-like bimodal microstructure consisting of a coarse-grained Cr phase surrounded by a 3D interconnected network of an ultrafine-grained W phase. The composite exhibited substantial improvements in ductility as well as high-temperature strength compared to pure W and Cr. After undergoing W heavy ion irradiation, the damaged Cr-W composite with a two-phase bimodal microstructure showed a comparable deuterium retention capacity to pure W. Finally, the potential applicability as PFM is discussed. [Display omitted] [ABSTRACT FROM AUTHOR]

The current clinical assessment of fracture risk lacks information about the inherent quality of a person's bone tissue. Working toward an imaging-based approach to quantify both a bone tissue quality marker (tissue hydration as water bound to the matrix) and a bone microstructure marker (porosity as water in pores), we hypothesized that the concentrations of bound water (C bw) are lower and concentrations of pore water (C pw) are higher in patients with osteoporosis (OP) than in age- and sex-matched adults without the disease. Using recent developments in ultrashort echo time (UTE) magnetic resonance imaging (MRI), maps of C bw and C pw were acquired from the uninjured distal third radius (Study 1) of 20 patients who experienced a fragility fracture of the distal radius (Fx) and 20 healthy controls (Non-Fx) and from the tibia mid-diaphysis (Study 2) of 30 women with clinical OP (low T-scores) and 15 women without OP (normal T-scores). In Study 1, C bw was significantly lower (p = 0.0018) and C pw was higher (p = 0.0022) in the Fx than in the Non-Fx group. In forward stepwise, logistic regression models using Bayesian Information Criterion for selecting the best set of predictors (from imaging parameters, age, BMI, and DXA scanner type), the area-under-the-receiver operator characteristics-curve (AUC with 95 % confidence intervals) was 0.73 (0.56, 0.86) for hip aBMD (best predictors without MRI) and 0.86 (0.70, 0.95) for the combination of C bw and C pw (best predictors overall). In Study 2, C bw was significantly lower (p = 0.0005) in women with OP (23.8 ± 4.3 1H mol/L) than in women without OP (29.9 ± 6.4 1H mol/L); C pw was significantly higher by estimate of 2.9 1H mol/L (p = 0.0298) with clinical OP, but only when accounting for the type of UTE-MRI scan with 3D providing higher values than 2D (p < 0.0001). Lastly, C bw , but not C pw , was sensitive to bone forming osteoporosis medications over 12-months. UTE-MRI-derived measurements of bound and pore water concentrations are potential, aBMD-independent predictors of fracture risk. • UTE-MRI quantifies concentrations of bound and pore water in the radius and tibia. • These measurements of matrix hydration and cortical porosity are predictors of bone fragility. • They are likely independent of DXA-derived areal bone mineral density. [ABSTRACT FROM AUTHOR]

• HeatLMD code was used to predict and analyse tin erosion in ASDEX-Upgrage liquid metal divertor experiment. • One expected, one hypothetical and one experimental scenarios were investigated. • The resulting erosion does not match the observed core radiation increase. A liquid metal Capillary Porous System (CPS) test module filled with tin was studied in the ASDEX Upgrade (AUG) outer divertor. The CPS module was flush mounted as part of a target tile and exposed using the AUG divertor manipulator. In order to predict tin erosion from the designed module under typical AUG divertor loading conditions, the experiment was interpreted using the HeatLMD code. Preceding test exposures of the CPS in the high heat flux facility GLADIS were performed and interpreted by modelling to quantify the thermo-mechanical properties of the module. The results for the reference AUG discharge indicated a total of 2.6 × 1017 tin atoms (51 μg) would be eroded during the exposure, predominantly through temperature enhanced sputtering. The vapour cooling power was predicted to be negligible (5 kW/m2at the end of a 5 s exposure with heat flux from the plasma of 2 MW/m2). The module was expected to be compatible with plasma operation, with tin erosion too low for any significant effect on the plasma performance. However, interpretative modelling of the experimental discharge with the highest exposure time yielded significantly lower tin erosion than observed. To be attributed to tin radiation the experimentally observed increase in total radiative power (1.5 MW) would require 2 × 1018 tin atoms (peak calculated erosion rate) radiating in the core plasma. This would require every tin atom eroded, to reach the core, which is unlikely. [ABSTRACT FROM AUTHOR]

The blistering and near-surface deuterium retention of a Y 2 O 3 -doped tungsten (W) and two different pure W grades were studied after exposure to deuterium (D) plasma at elevated temperatures (370, 450 and 570 K). Samples were exposed to a deuterium fluence of 6 × 10 24 D m −2 applying a moderate ion flux of about 9 × 10 19 D m −2 s −1 at an ion energy of 38 eV/D. Morphological modifications at the surface were analyzed by confocal laser scanning microscopy and scanning electron microscopy. The D depth profiles and the accumulated D inventories within the topmost 8 μm were determined by nuclear reaction analysis. Blistering and deuterium retention were strongly dependent on the implantation temperature. In addition, blistering was sensitively influenced by the used tungsten grade, although the total amount of retained D measured by nuclear reaction analysis was comparable. Among the three different investigated tungsten grades, Y 2 O 3 -doped W exhibited the lowest degree of surface modification despite a comparable total D retention. [ABSTRACT FROM AUTHOR]