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Multiple Sequence Variants in STAC3 Affect Interactions with CaV1.1 and Excitation-Contraction Coupling
Abstract not provided
Tributyltin chloride increases phenylephrine-induced contraction and vascular stiffness in mesenteric resistance arteries from female rats
Tributyltin chloride (TBT) is an organotin compound that reduces estrogen levels in female rats. We aimed to investigate the effects of TBT exposure on vascular tonus and vascular remodelling in the resistance arteries of female rats. Rats were treated daily with TBT (500 ng/kg) for 15 days. TBT did not change arterial blood pressure but did modify some morpho-physiological parameters of third-order mesenteric resistance arteries in the following ways: (1) decreased lumen and external diameters; (2) increased wall/lm ratio and wall thickness; (3) decreased distensibility and increased stiffness; (4) increased collagen deposition; and (5) increased pulse wave velocity. TBT exposure increased the phenylephrine-induced contractile response in mesenteric resistance arteries. However, vasodilatation responses induced by acetylcholine and sodium nitroprusside were not modified by TBT. It is suggested that TBT exposure reduces vascular nitric oxide (NO) production, because:(1) L-NAME incubation did not cause a leftward shift in the concentration–response curve for phenylephrine; (2) both eNOS protein expression; (3) in situ NO production were reduced. Incubation with L-NAME; and (4) SOD shifted the phenylephrine response curve to the left in TBT rats. Tiron, catalase, ML-171 and VAS2870 decreased vascular reactivity to phenylephrine only in TBT rats. Moreover, increased superoxide anion production was observed in the mesenteric resistance arteries of TBT rats accompanied by an increase in gp91phox, catalase, AT{sub 1} receptor and total ERK1/2 protein expression. In conclusion, these findings show that TBT induced alterations are most likely due to a reduction of NO production combined with increased O{sub 2}{sup −} production derived from NADPH oxidase and ERK1/2 activation. These findings offer further evidence that TBT is an environmental risk factor for cardiovascular disease. - Highlights: • Tributyltin chloride reduces estrogen levels in female rats. • Treatment with TBT resulted in increased contractile response to phenylephrine. • Collagen deposition could be responsible for vascular stiffness after TBT exposure.
Ionic Contraction across the Lanthanide Series Decreases the Temperature-Induced Disorder of the Water Coordination Sphere
In liquid, temperature affects the structures of lanthanide complexes in multiple ways that depend upon complex interactions between ligands, anions, and solvent molecules. The relative simplicity of lanthanide aqua ions (Ln 3+ ) make them well suited to determine how temperature induces structural changes in lanthanide complexes. In this work, we performed a combination of ab initio molecular dynamics (AIMD) simulations and extended X-ray absorption fine structure (EXAFS) measurements, both at 25 and 90 °C, to determine how temperature affects the first- and second-coordination spheres of three Ln 3+ (Ce 3+ , Sm 3+ , and Lu 3+ ) aqua ions. AIMD simulations show first lanthanide coordination spheres that are similar at 25 and 90 °C, more so for the Lu 3+ ion that remains as eight-coordinate than for the Ce 3+ and Sm 3+ ions that change their preferred coordination number from nine (at 25 °C) to eight (at 90 °C). The measured EXAFS spectra are very similar at 25 and 90 °C, for the Ce 3+ , Sm 3+ , and Lu 3+ ions, suggesting that the dynamical disorder of the Ln 3+ ions in liquid water is sufficient such that temperature-induced changes do not clearly manifest changes in the structure of the three ions. Both AIMD simulations and EXAFS measurements show very similar structures of the first coordination sphere of the Lu 3+ ion at 25 and 90 °C.
Accelerated Convergence of Contracted Quantum Eigensolvers through a Quasi-Second-Order, Locally Parameterized Optimization
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Unusual Non-Bulk Properties in Nanoscale Materials: Thermal Metal-Metal Bond Contraction of [gamma]-Alumina-Supported Pt Catalysts
Abstract not provided
Bonded Radii and the Contraction of the Electron Density of the Oxygen Atom by Bonded Interactions
The bonded radii for more than 550 bonded pairs of atoms, comprising more than 50 crystals, determined from experimental and theoretical electron density distributions, are compared with the effective ionic, ri(M), and crystal radii, rc(M), for metal atoms, M, bonded to O atoms. At odds with the fixed ionic radius of 1.40 Å, assumed for the O atom in the compilation of the ionic radii, the bonded radius for the atom, rb(O), is not fixed but displays a relatively wide range of values as the O atom is progressively polarized by the M-O bonded interactions: as such, rb(O) decreases systematically from 1.40 Å (the Pauling radius of the oxide anion) as bond lengths decrease when bonded to an electropositive atom like sodium, to 0.64 Å (Bragg’s atomic radius of the O atom) when bonded to an electronegative atom like nitrogen. Both rb(M) and rb(O) increase in tandum with the increasing coordination number of the M atom. The bonded radii of the M atoms are highly correlated with both ri(M) and rc(M), but they both depart systematically from rb(M) and become smaller as the electronegativity of the M atom increases and the M-O bond length decreases. The well-developed correlations between both sets of radii and rb(M) testifies to the relative precision of both sets of radii and the fact that both sets are highly correlated the M-O bond 1 lengths. On the other hand, the progressive departure of rb(O) from the fixed ionic radius of the O atom with the increasing electronegativity of the bonded M atom indicates that any compilation of sets of ionic radii, assuming that the radius for the oxygen atom is fixed in value, is problematical and impacts on the accuracy of the resulting sets of ionic and crystal radii thus compiled. The assumption of a fixed O atom radius not only results in a negative ionic radii for several atoms, but it also results in values of rb(M) that are much as ~ 0.6 Å larger than the ri(M) and rc(M) values, respectively, particularly for the more electronegative M atoms. On the other hand, the ionic radii are in closer agreement with rb(M) for the more electropositive atoms. Notwithstanding that ionic radii are typically smaller than bonded radii, particularly for the more electronegative atoms, they have been used with considerable success in understanding and rationalizing problems and properties in crystal chemistry primarily because both ionic and crystal radii are highly correlated on a one-to-one basis with both the bonded radii and the associated M-O bond lengths. The lack of agreement between the effective ionic and crystal radii and the bonded radii for the more shared bonded interactions is ascribed to the progressive increase in the polarization of the O atom by the bonded atoms with a concomitant decrease in its radius, a factor that was neglected in the compilation of ionic and crystal radii for fluorides, oxides, sulfides and nitrides. This accounts for ionic radii for these materials being smaller than the bonded radii for the more electronegative atoms.
Size and Shape Effects of Pd@Pt Core-Shell Nanoparticles: Unique Role of Surface Contraction and Local Structural Flexibility
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Anomalous thermal contraction of the first coordination shell in metallic alloy liquids
Abstract not provided
Coordination-resolved local bond contraction and electron binding-energy entrapment of Si atomic clusters and solid skins
Consistency between x-ray photoelectron spectroscopy measurements and density-function theory calculations confirms our bond order-length-strength notation-incorporated tight-binding theory predictions on the quantum entrapment of Si solid skin and atomic clusters. It has been revealed that bond-order deficiency shortens and strengthens the Si-Si bond, which results in the local densification and quantum entrapment of the core and valence electrons. Unifying Si clusters and Si(001) and (111) skins, this mechanism has led to quantification of the 2p binding energy of 96.089 eV for an isolated Si atom, and their bulk shifts of 2.461 eV. Findings evidence the significance of atomic undercoordination that is of great importance to device performance.
Fast skeletal myosin-binding protein-C regulates fast skeletal muscle contraction
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EVIDENCE FOR DARK MATTER CONTRACTION AND A SALPETER INITIAL MASS FUNCTION IN A MASSIVE EARLY-TYPE GALAXY
Stars and dark matter account for most of the mass of early-type galaxies, but uncertainties in the stellar population and the dark matter profile make it challenging to distinguish between the two components. Nevertheless, precise observations of stellar and dark matter are extremely valuable for testing the many models of structure formation and evolution. We present a measurement of the stellar mass and inner slope of the dark matter halo of a massive early-type galaxy at z = 0.222. The galaxy is the foreground deflector of the double Einstein ring gravitational lens system SDSSJ0946+1006, also known as the 'Jackpot'. By combining the tools of lensing and dynamics we first constrain the mean slope of the total mass density profile ({rho}{sub tot}{proportional_to}r{sup -{gamma}{sup '}}) within the radius of the outer ring to be {gamma}' = 1.98 {+-} 0.02 {+-} 0.01. Then we obtain a bulge-halo decomposition, assuming a power-law form for the dark matter halo. Our analysis yields {gamma}{sub DM} = 1.7 {+-} 0.2 for the inner slope of the dark matter profile, in agreement with theoretical findings on the distribution of dark matter in ellipticals, and a stellar mass from lensing and dynamics M{sup LD}{sub *} = 5.5{sub -1.3}{sup +0.4} Multiplication-Sign 10{sup 11} M{sub Sun }. By comparing this measurement with stellar masses inferred from stellar population synthesis fitting we find that a Salpeter initial mass function (IMF) provides a good description of the stellar population of the lens while the probability of the IMF being heavier than Chabrier is 95%. Our data suggest that growth by accretion of small systems from a compact red nugget is a plausible formation scenario for this object.
Exploring the market for third-party-owned residential photovoltaic systems: insights from lease and power-purchase agreement contract structures and costs in California
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Study of symmetry breaking in a relativistic Bose gas using the contraction algorithm
Not Available