173 research outputs found
First-principle solubilities of alkali and alkaline earth metals in Mg-B alloys
By devising a novel framework, we present a comprehensive theoretical study
of solubilities of alkali (Li, Na, K, Rb, Cs) and alkaline earth (Be, Ca, Sr,
Ba) metals in the he boron-rich Mg-B system. The study is based on
first-principle calculations of solutes formation energies in MgB, MgB,
MgB alloys and subsequent statistical-thermodynamical evaluation of
solubilities. The advantage of the approach consists in considering all the
known phase boundaries in the ternary phase diagram. Substitutional Na, Ca, and
Li demonstrate the largest solubilities, and Na has the highest (0.5-1 % in
MgB at K). All the considered interstitials have negligible
solubilities. The solubility of Be in MgB can not be determined because the
corresponding low-solubility formation energy is negative indicating the
existence of an unknown ternary ground state. We have performed a
high-throughput search of ground states in binary Mg-B, Mg-, and B-
systems, and we construct the ternary phase diagrams of Mg-B- alloys based
on the stable binary phases. Despite its high temperature observations, we find
that SrMg is not a low-temperature equilibrium structure. We also
determine two new possible ground states CaB and RbB, not yet
observed experimentally.Comment: 5 figure
Correlation of cutaneous tension distribution and tissue oxygenation with acute external tissue expansion
Today, the biomechanical fundamentals of skin expansion are based on viscoelastic models of the skin. Although many studies have been conducted in vitro, analyses performed in vivo are rare. Here, we present in vivo measurements of the expansion at the skin surface as well as measurement of the corresponding intracutaneous oxygen partial pressure. In our study the average skin stretching was 24%, with a standard deviation of 11%, excluding age or gender dependency. The measurement of intracutaneous oxygen partial pressure produced strong inter-individual fluctuations, including initial values at the beginning of the measurement, as well as varying individual patient reactions to expansion of the skin. Taken together, we propose that even large defect wounds can be closed successfully using the mass displacement caused by expansion especially in areas where soft, voluminous tissue layers are present
Angiotensin-(1-7) enhances LTP in the hippocampus through the G-protein-coupled receptor Mas.
The renin-angiotensin system not only plays a critical role in blood pressure control but is also involved in learning and memory mechanisms. In addition to angiotensin (Ang) II, Ang-(1-7) may also have important biological activities in the brain. Here, we show for the first time that Ang-(1-7) enhances long-term potentiation (LTP) in the CA1 region of the hippocampus. Our studies with AT1 receptor antagonists and selective Ang-(1-7) receptor antagonists demonstrate the existence of a distinct Ang-(1-7) receptor in the brain, the G-protein-coupled receptor Mas, encoded by the Mas protooncogene. We also show that the genetic deletion of this receptor abolishes the Ang-(1-7)-induced enhancement of LTP. Thus, we firstly demonstrate that Ang-(1-7) influences the induction of LTP in limbic structures implicating its distinct function in learning and memory mechanisms; secondly, we have identified Mas as a functional receptor for Ang-(1-7) in the brain
Angiotensin-(1-7) enhances LTP in the hippocampus through the G-protein-coupled receptor Mas.
The renin-angiotensin system not only plays a critical role in blood pressure control but is also involved in learning and memory mechanisms. In addition to angiotensin (Ang) II, Ang-(1-7) may also have important biological activities in the brain. Here, we show for the first time that Ang-(1-7) enhances long-term potentiation (LTP) in the CA1 region of the hippocampus. Our studies with AT1 receptor antagonists and selective Ang-(1-7) receptor antagonists demonstrate the existence of a distinct Ang-(1-7) receptor in the brain, the G-protein-coupled receptor Mas, encoded by the Mas protooncogene. We also show that the genetic deletion of this receptor abolishes the Ang-(1-7)-induced enhancement of LTP. Thus, we firstly demonstrate that Ang-(1-7) influences the induction of LTP in limbic structures implicating its distinct function in learning and memory mechanisms; secondly, we have identified Mas as a functional receptor for Ang-(1-7) in the brain
- …