First stage strontium-graphite intercalation compound (GIC) is successfully synthesized using a recent method based on eutectic medium LiCl–KCl. The bulk compound is obtained after immersing a ...graphite platelet in strontium-molten salt solution at 450 °C for several days. Using such bulk GIC, an accurate structural study is performed by applying X-ray diffraction techniques (00l, hk0 and rotating crystal method). It is validated that SrC6, similarly to most MC6 compounds, crystallizes in a hexagonal P63/mmc space group with subsequent parameters a = b = 431 pm and c = 988 pm
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A solid-liquid method is used to synthesize the first stage bulk BaC6 graphite intercalation compound (GIC). This way of synthesis allows the preparation of bulk and massive samples useful for ...crystal structure determination. Through a eutectic medium LiCl–KCl, and by submerging a graphite platelet in barium-molten solution at 450 °C for several days, the bulk BaC6 compound is obtained and X-ray diffraction investigations allowed a complete structural study. The collected data certify that BaC6 crystallizes in the hexagonal P63/mmc space group with the following parameters a = b = 430.6 pm and c = 1058.2 pm.
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Thanks to its lamellar structure, graphite can host various chemical species between its interplanar spaces to form Graphite Intercalation Compounds (GIC). Intercalation of metals into graphite can ...lead to remarkable modifications of the physical properties of the sample with respect to pristine graphite as for instance superconductivity. In this paper, we report attempts made to intercalate strontium, barium and ytterbium into graphite, using a recent method involving a LiCl-KCl molten salt as a reaction medium. Resulting samples are characterized regarding their structure and chemical composition. We reveal the obtaining of bulk SrC
6
and BaC
6
and a superficial intercalation of ytterbium leading to superconducting YbC
6
domains only, as confirmed by dc-magnetization measurements.
The synthesis route in molten salts allows the bulk intercalation into graphite of elements hardly intercalated by themselves. XRD and ion beam analyses show for instance the possible synthesis of SrC
6
.
Greenhouse gas emissions from ruminant livestock production systems contribute significantly to the environmental footprint of agriculture. Emissions are lower for feedlot systems than for ...grass-based systems primarily because of the extra time required for grass-finished cattle to reach slaughter weight. In contrast, legume forages are of greater quality than grasses, which enhances intake and food conversion efficiencies, leading to improvements in production and reductions in environmental impacts compared with forage grasses. In addition, the presence of certain bioactives in legumes such as condensed tannins (CT) enhance the efficiency of energy and protein use in ruminants relative to grasses and other feeds and forages. Grazing tannin-containing legumes also reduce the incidence of bloat and improve meat quality. Synergies among nutrients and bioactives when animals graze diverse legume pastures have the potential to enhance these benefits. Thus, a diversity of legumes in feeding systems may lead to more economically, environmentally, and socially sustainable beef production than grass monocultures or feedlot rations.
We measured the temperature dependent resistivity, varrho(T), of the intercalated graphite superconductor CaC6 as a function of pressure up to 16 GPa. We found a large linear increase of critical ...temperature, Tc, from the ambient pressure value 11.5 K up to 15.1 K, the largest value for intercalated graphite, at 7.5 GPa. At approximately 8 GPa, a jump of varrho and a sudden drop of Tc down to approximately 5 K indicates the occurrence of a phase transition. Our data analysis suggests that a pressure-induced phonon softening related to an in-plane Ca phonon mode is responsible for the Tc increase and that higher pressures greater, similar8 GPa lead to a structural transition into a new phase with a low Tc less, similar3 K.
High-quality homoepitaxial diamond films have been grown on 100-type Ib synthetic diamond, and boron doped by diborane from 5×10
16 to 8×10
20
cm
−3. The current–temperature characteristics from 300 ...to 1000
K have been measured and fitted by the general expression of the conductivity in a compensated semiconductor in the ionisation regime. The saturation of the conductivity is observed between 680 and 1000
K for the samples doped below 2×10
17
cm
−3. In the range 10
18–10
19
cm
−3, an activation energy of 185
meV is observed between 500 and 1000
K and around 368
meV between 300 and 500
K. The activation energy of 185
meV corresponds to half the boron ionisation energy, and is related to the conduction regime in an uncompensated semiconductor. The evolution of these activation energies and of the room-temperature resistivity with the boron doping are presented.
Serum- and glucocorticoid-regulated kinase 1 (SGK1) is an aldosterone-regulated early response gene product that regulates the activity of several ion transport proteins, most notably that of the ...epithelial sodium channel (ENaC). Recent evidence has established that SGK1 phosphorylates and inhibits Nedd4-2 (neural precursor cell-expressed, developmentally down-regulated protein 4-2), a ubiquitin ligase that decreases cell surface expression of the channel and possibly stimulates its degradation. The mechanistic basis for this SGK1-induced Nedd4-2 inhibition is currently unknown. In this study we show that SGK1-mediated phosphorylation of Nedd4-2 induces its interaction with members of the 14-3-3 family of regulatory proteins. Through functional characterization of Nedd4-2-mutant proteins, we demonstrate that this interaction is required for SGK1-mediated inhibition of Nedd4-2. The concerted action of SGK1 and 14-3-3 appears to disrupt Nedd4-2-mediated ubiquitination of ENaC, thus providing a mechanism by which SGK1 modulates the ENaC-mediated Na+ current. Finally, the expression pattern of 14-3-3 is also consistent with a functional role in distal nephron Na+ transport. These results demonstrate a novel, physiologically significant role for 14-3-3 proteins in modulating ubiquitin ligase-dependent pathways in the control of epithelial ion transport.
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