Structure and magnetic properties of new compounds CdYFeWO_7

The solid solutions of CdYFeWO7,which are cubic pyrochlores of the type A2B2O7,have been prepared and their structures were determined using Ab initio method.Rietveld refinement of the powder XRD data showed that CdYFeWO7 adopted cubic(Fd-3m) structure,while oxides crystallized in a defect-pyrochlore structure where both O(48f) and O'(8b) sites were partially occupied,and the frustrated cations sublattice precluded long range ordering of Fe/W in the pyrochlore structure.Charge distribution analysis also sug...     

Design and synthesis of new cross-linking agents

We have previously synthesized 6-vinylated guanosine derivatives by new Pd(0)-catalyzed cross-coupling reaction using guanosine 6-O-tosylate and vinyltributyl-stannane. Its potentials as a cross-linking agent have been demonstrated by adduct formation with guanosine and cytidine. But these 6-vinylated derivatives could not be incorporated to oligonucleotide because of chemical instability. In this paper, we report new deoxyguanosine derivatives with substituted olefin (2 and 3), which were designed to control the reactivity of vinyl functional group. Although either 2 or 3 did not formed the adducts with nucleobases, these compounds reacted with hydroxylamine hydrochloride in the presence of acid catalyst. The reactivity was in the order of 1 > 2 > 3. These results suggest that new guaosine derivatives (2 and 3) have moderate reactivity toward nucleophiles and are expected to be stable in incorporating into oligonucleotides as a cross-linking agent.     

Structural,morphological and optical properties of new Eu-doped and vacancied lead molybdato-tungstates

A new tetragonal,scheelite-type Pb_(1-3 x)■_xEU_(2 x)(MoO_4)_(1-3 x)(WO_4)_(3 x)(0 x ≤0.1970 and ■ denotes A-site vacancies) solid solution was synthesized via solid state reaction method. The X-ray diffraction(XRD) and scanning electron microscopy(SEM) results confirm the formation of single, tetragonal scheelite-type phases(space group I4_1/a) with the average crystallite size in the range of ～20-100 μm. Substitution of Pb~(2+) with Eu~(3+) is relatively easy despite the large difference in ionic radii, and the formation of vacancies is necessary to compensate the excess positive charge in PbMoO_4 framework. A change in lattice parameters(both a and c as well as lattice parameter ratio c/a) and progressive deformation of MoO_4 and WO_4 tetrahedra with increasing Eu concentration are observed. Thermal stability of Eu-doped materials strongly depends on the concentration of Eu3+ ions. The Pb_(1-3 x)■_xEu_(2 x)(MoO_4)_(1-3 x)(WO_4)_(3 x) solid solution for x=0.0098 shows the highest melting point(1057 ℃) which is slightly higher than that of pure PbMoO_4(1040 ℃). The UV-vis diffuse reflectance spectroscopy(DRS) and the Tauc plots were used to extrapolate the optical indirect band gap(E_g) of doped materials. Eu-doped ceramics are insulators(E_g 3 eV) and their band gap nonlinearly decreases with increasing dopant concentration.     

A new series of C3-aza carbocyclic influenza neuraminidase inhibitors: synthesis and inhibitory activity

The synthesis and influenza neuraminidase inhibitory activity of a new series of C3-aza carbocyclic neuraminidase inhibitors are described. Analogues 3c and 3j, bearing a 3-pentyl group, exhibit influenza A inhibitory activities comparable to that of 1.     

Design of a C/EBP-specific, dominant-negative bZIP protein with both inhibitory and gain-of-function properties

We have developed a bZIP protein, GBF-F, with both dominant-negative (DN) and gain-of-function properties. GBF-F is a chimera consisting of two components: the DNA binding (basic) region from the plant bZIP protein GBF-1 (GBF) and a leucine zipper (F) designed to preferentially heterodimerize with the C/EBP alpha leucine zipper. Biochemical studies show that GBF-F preferentially forms heterodimers with C/EBP alpha and thus binds a chimeric DNA sequence composed of the half-sites recognized by the C/EBP and GBF basic regions. Transient transfections in HepG2 hepatoma cells show that both components of GBF-F are necessary for inhibition of C/EBP alpha transactivation. When the C/EBP alpha leucine zipper is replaced with that of either GCN4 or VBP, the resulting protein can transactivate a C/EBP cis-element but is not inhibited by GBF-F, indicating that the specificity of dominant-negative action is determined by the leucine zipper. All known members of the C/EBP family contain similar leucine zipper regions and are inhibited by GBF-F. GBF-F also exhibits gain-of-function properties, since, with the essential cooperation of a C/EBP family member, it can transactivate a promoter containing the chimeric C/EBP/GBF site. This protein therefore has potential utility both as a dominant-negative inhibitor of C/EBP function and as an activator protein with novel DNA sequence specificity.     

Thio-sugars. IV: Design and synthesis of S-linked fucoside analogs as a new class of alpha-L-fucosidase inhibitors

alpha-1-Thio-L-fucose derivative 4 and 5 as new alpha-fucosidase inhibitors (K1 = 4.6, and 5.9 microM) have been synthesized in three steps by base catalyzed coupling with bromonitromethane followed by reduction of the nitro group with sodium borohydride/cobalt chloride complex and acetylation.     

Design and synthesis of a new type of non steroidal human aromatase inhibitors

The structure-activity relationship study of one of recently described aromatase inhibitors, compound 1 (MR20814), allowed us to design some related derivatives as potential new inhibitors. Among those we synthesized, chlorophenylpyridylmethylenetetrahydroindolizinone 5 (MR20492) exhibited in vitro a ten-fold higher inhibition of the enzyme (IC50 = 0.2 +/- 0.0 microM and Ki = 10.3 +/- 3.3 nM).     

Solubility of lead and zinc compounds in ammoniacal ammonium sulphate solutions

The solubilities of lead sulphide, sulphate, chloride and oxide and zinc sulphide, sulphate and oxide in ammoniacal ammonium sulphate solutions have been determined. Solubility diagrams showing the effect of varying ammonia and ammonium sulphate concentrations are presented. The presence of high levels of zinc or copper is shown to reduce lead solubility to extremely low levels (0.1 (g/l Pb). Solutions containing lead were found to be unstable when removed from contact with the initial dissolving compound and a mechanism is postulated for the dissolution of lead compounds involving the production of a metastable intermediate complex.     

Motor development: A new synthesis.

The study of the acquisition of motor skills, long moribund in developmental psychology, has seen a renaissance in the last decade. Inspired by contemporary work in movement science, perceptual psychology, neuroscience, and dynamic systems theory, multidisciplinary approaches are affording new insights into the processes by which infants and children learn to control their bodies. In particular the new synthesis emphasizes the multicausal, fluid, contextual, and self-organizing nature of developmental change, the unity of perception, action, and cognition, and the role of exploration and selection in the emergence of new behavior. Studies are concerned less with how children perform and more with how the components cooperate to produce stability or engender change. Such process approaches make moot the traditional nature–nurture debates. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Microbial inhibitory properties and stability of topotecan hydrochloride injection

The viability of five microorganisms in topotecan 1 mg/mL (as the hydrochloride salt) in sterile water and the stability of the drug were studied. Duplicate portions of topotecan 1 mg/mL were inoculated with Escherichia coli. The process was repeated for Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, and Aspergillus niger. Samples were removed from each solution initially and after 6, 16, and 24 hours and 3, 7, 14, 21, and 28 days of incubation at 20-25 degrees C. To test stability, vials of reconstituted topotecan hydrochloride injection were stored at each of three temperatures--5, 25, and 30 degrees C--and other vials were used for time zero analysis. For each temperature, vials were removed at 1, 7, and 14 days and the remaining vials at 28 days for analysis by high-performance liquid chromatography and for visual and pH assessment. P. aeruginosa, S. aureus, and E. coli lost viability at 16 hours, 24 hours, and 28 days, respectively. C. albicans and A. niger did not lose viability, but their numbers did not grow. No differences in color or clarity were observed, and pH was constant. In all solutions, the topotecan concentration was > 98% of the initial concentration. Topotecan 1 mg/mL in sterile water stored at 20-25 degrees C for up t 28 days did not support growth of the five microorganisms studied; in solutions stored at 5, 25, or 30 degrees C for up to 28 days, topotecan 1 mg/mL remained stable.     

Effect of lead on globin synthesis in vitro

A defect in heme synthesis is well documented to occur in lead intoxication. Globin synthesis and the alpha/beta globin chain synthesis ratio have been shown to be disturbed in lead poisoning. To elucidate further the nature of the inhibitory effect of lead on hemoglobin synthesis, reticulocyte-rich peripheral blood samples have been incubated with lead at concentrations of 10(-6), 10(-5), and 10(-4) M, equivalent to 20, 200, and 2,000 mug/dl (.96, 9.6 and 96.0 mumol/l), respectively. The incorporation of tritiated leucine into globin was determined. Globin chain synthesis decreased to 85, 49 and 15% of the control value with increasing lead concentrations. The effect of heme on inhibition of globin synthesis by lead was studied by incubating reticulocyte-enriched blood with lead 10(-5) M (200 mug/dl; 9.6 mumol/l) in the presence or absence of heme at a concentration of 10(-3) M. Lead alone depressed the incorporation of tritiated leucine to 45% of control, while globin synthesis with heme alone was 109% of control. Although in the presence of both heme and lead, the mean incorporation of leucine into globin was 69.2% of control, the increase was not significantly different from that obtained with lead alone. It is concluded that (1) lead has an inhibitory effect on globin synthesis at a concentration considered to be within the acceptable range encountered in environmental lead pollution, and the extent of inhibition is dose-dependent; (2) the effect of lead on globin synthesis is not significantly prevented by heme and, therefore, does not appear to be mediated through the well-documented inhibitory effect of lead on heme synthesis.     

Thermodynamic properties of scandium-copper compounds

We have determined the Gibbs energy, the enthalpy, and the entropy of formation for the compounds ScCu₄, ScCu₂, and ScCu by measuring the emf of galvanic cells in the temperature range 845–980 K. We compared the experimental results obtained with known literature data. __________ Translated from Poroshkovaya Metallurgiya, Nos. 1–2(447), pp. 87–91, January–February, 2006.     

Design and synthesis of new secretory phospholipase A2 inhibitor of a phospholipid analog

All stereoisomers of N-acyl-4,5-disubstituted oxazolidinone phospholipid analogs were synthesized by regio and stereoselective epoxide ring opening accompanied by introduction of an amino group. The (4R,5S)-derivative showed stronger inhibitory activity toward type II phospholipase A2 than the 4-substituted oxazolidinone phospholipid analog previously reported.     

Kv8.1, a new neuronal potassium channel subunit with specific inhibitory properties towards Shab and Shaw channels

Outward rectifier K+ channels have a characteristic structure with six transmembrane segments and one pore region. A new member of this family of transmembrane proteins has been cloned and called Kv8.1. Kv8.1 is essentially present in the brain where it is located mainly in layers II, IV and VI of the cerebral cortex, in hippocampus, in CA1-CA4 pyramidal cell layer as well in granule cells of the dentate gyrus, in the granule cell layer and in the Purkinje cell layer of the cerebellum. The Kv8.1 gene is in the 8q22.3-8q24.1 region of the human genome. Although Kv8.1 has the hallmarks of functional subunits of outward rectifier K+ channels, injection of its cRNA in Xenopus oocytes does not produce K+ currents. However Kv8.1 abolishes the functional expression of members of the Kv2 and Kv3 subfamilies, suggesting that the functional role of Kv8.1 might be to inhibit the function of a particular class of outward rectifier K+ channel types. Immunoprecipitation studies have demonstrated that inhibition occurs by formation of heteropolymeric channels, and results obtained with Kv8.1 chimeras have indicated that association of Kv8.1 with other types of subunits is via its N-terminal domain.