Effects of calphobindin II (annexin VI) on procoagulant and anticoagulant activities of cultured endothelial cells.

Effects of human placental calphobindin II (CPB-II) on the protein C activation and prothrombin activation on the cell surface of cultured calf pulmonary arterial endothelial cells have been investigated. CPB-II inhibited thrombin generation by factor Xa bound to the surface of the cultured endothelial cells in a dose-dependent manner. The amount (IC50) of CPB-II causing the inhibition at 50% was estimated to be approximately 10 nM. CPB-II was found to be ineffective, however, in the protein C activation by thrombin-thrombomodulin (TM) complex on the cell surface. Assay using purified TM revealed that CPB-II was able to exhibit the inhibitory potency for the protein C activation exclusively in the reconstituted system with negatively charged phospholipids. These results suggest that the neutral phospholipids participate in the protein C activation through the thrombin-TM system on the endothelial cell surface. The ability of CPB-II to inhibit procoagulant activity without affecting anticoagulant activity on the cultured endothelial cells is probably related to its potential physiological function, while it is able to exert various degrees of influence upon these activities in blood coagulation by interacting with negatively charged phospholipids in vitro.     

Dynamics of iodine anions in KI and LiI aqueous solutions studied by <Superscript>127</Superscript>I nuclear resonant quasi-elastic scattering

The dynamics of iodine ions in potassium iodide (KI) and lithium iodide (LiI) aqueous solutions have been studied through ¹²⁷I nuclear resonant quasi-elastic scattering (NRQES). A newly developed Si (12 2 2) double crystal monochromator for ¹²⁷I 57.6 keV excitation is used. Broadening due to a diffusive motion is measured in the energy spectra of the NRQES from the solutions.     

Stereospecific epoxide-opening reactions of 1,1-dibromo-3,4-epoxy-1-alkenes with carbon nucleophiles

The stereospecific epoxide-opening reactions of 1,1-dibromo-3,4-epoxy-1-alkenes with allyltributylstannane and with ketene silyl acetals in the presence of a Lewis acid are described. Both the reactions occurred regioselectively at the allylic position via an S_N2 process giving rise to a single product, respectively. Treatment of the products by the latter reaction with p-TsOH afforded various 3,4-anti- and 3,4-syn-disubstituted γ-lactones in a highly stereoselective manner and high yields.     

Thermoreversible gelation with hydrogen‐bonded zipper‐like crosslink junctions

Thermoreversible gelation of polymer chains bearing hydrogen‐bonding functional groups is studied by off‐lattice Monte Carlo simulation with semiflexible bead‐and‐spring model chains. To see the formation of zipper‐like sequential crosslink junctions (domino effect), we introduce stabilization energy ?Δε between the nearest neighboring hydrogen‐bonded beads along a chain in addition to the ordinary pairwise hydrogen‐bond energy ?ε. It is found that the condition nθ/ = 2 is fulfilled at the sol/gel transition point, where is the average zipper length, θ the zipper content per chain, and n the total number of beads on a chain. It is also shown that, at low temperature, zipper growth dominates the nucleation of new zippers, and as a result, there is another transition from a three‐dimensional network to a pairwisely bound state (network/pair transition). © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3331–3336, 2005     

Amphiphilic p-sulfonatocalix[4]arene-coated CdSe/ZnS quantum dots for the optical detection of the neurotransmitter acetylcholine

Water-soluble CdSe/ZnS (core-shell) semiconductor quantum dots surface-modified with tetrahexyl ether derivatives of p-sulfonatocalix[4]arene were synthesized for the optical detection of the neurotransmitter acetylcholine.     

Homogeneous SiGe crystals grown by using the traveling liquidus-zone method

It is indispensable to estimate a diffusion coefficient in a solution zone in order to grow a homogeneous crystal by using the traveling liquidus-zone (TLZ) method. To estimate the diffusion coefficient of Ge in the SiGe solution zone, result of a two-dimensional numerical simulation is compared with an experimental result. From the comparison, the diffusion coefficient is estimated to be 9.5×10⁻⁵ cm²/s. By using this coefficient, a sample translation rate for obtaining a homogeneous SiGe crystal is determined. By translating samples with appropriate rates, homogeneous Si_0.5Ge_0.5 crystals are successfully grown. The typical Ge composition is 0.496±0.006 for more than 13 mm long. The experimental result shows the homogeneity of ±1.2% in the mole fraction. This deviation corresponds to the variation of less than ±0.03% in the lattice constant. Since this variation is negligibly small, the homogeneity is excellent. Thus it is found that the TLZ method is the universal growth technique, which is applicable to the crystal growth of not only the III–V compounds but also the IV–IV compounds.     

Discovery of (E)-9,10-dehydroepothilones through chemical synthesis: on the emergence of 26-trifluoro-(E)-9,10-dehydro-12,13-desoxyepothilone B as a promising anticancer drug candidate

We provide a full account of the discovery of the (E)-9,10-dehydro derivatives of 12,13-desoxyepothilone B (dEpoB), a new class of antitumor agents with promising in vivo preclinical properties. The compounds, which are to date not available by modification of any of the naturally occurring epothilones, were discovered through total chemical synthesis. We describe how our investigations of ring-closing metathesis reactions in epothilone settings led to the first and second generation syntheses of (E)-9,10-dehydro-12,13-desoxyepothilone congener 6. With further modifications, the synthesis was applied to reach a 26-trifluoro derivative compound (see compound 7). To conduct such studies and in anticipation of future development needs, the total synthesis which led to the initial discovery of compound 7 was simplified significantly. The total synthesis methodology used to reach compound 7 was then applied to reach more readily formulated compounds, bearing hydroxy and amino functionality on the 21-position (see compounds 45, 62, and 63). Following extensive in vitro evaluations of these new congeners, compound 7 was nominated for in vivo evaluations in xenograft models. The data provided herein demonstrate a promising therapeutic efficacy, activity against large tumors, nonrelapseability, and oral activity. These results have identified compound 7 as a particularly promising compound for clinical development. The excellent, totally synthetic, route to 7 makes such a program quite feasible.     

Synthesis and pharmacological evaluation of procaterol derivatives having a tert-amino group

A series of procaterol derivatives having a tert-amino group was synthesized. Among them, a morpholino derivative (4a, R1 = H, NR2R3 = morpholino) showed beta-selective and rather potent adrenoceptor stimulant activities in an in vivo assay using anesthetized dogs. On the other hand, a morpholinopropanol analogue (4j, R1 = CH3, NR2R3 = morpholino) showed 400 times less potent bronchodilator activity than that of 4a. Some of the compounds showed weak bronchodilator activities and weak effects on the heart. It seems that steric hindrance around the nitrogen atom of catecholamines has a significant influence on beta-adrenoceptor stimulant activities. Compound 4a also showed anti-allergic action estimated in terms of the inhibition of homologous passive cutaneous anaphylaxis in rats.     

Cache-aware volume rendering methods with dynamic data reorganization

Journal of Visualization - &nbsp;We present two cache-aware methods for accelerating volume rendering on graphics processing units (GPUs). The proposed methods extend a previous method such...     

Strong Resistivity Anomaly in a New Low-Dimensional Conductor HfTe5

Temperature dependence of the resistivity, Hall coefficient and magnetic susceptibility of HfTe₅ with 1.5 wt. %, Zr is reported. Anisotropic large diamagnetism is reported and has the peak in the vicinity of 76 K. Temperature dependence of Hall coefficient under 117 kOe elearly shows the destruction of Fermi surface at about 90 K. HfTe₅ can be considered to be a semimetal and observed resistivity anomaly may be accompanied by the CDW formation along c-axis. We also discuss the mixed crystal effect with ZrTe₅ and present the data of quantum oscillation observed at low temperature.