3-Nitropropions?ure in Pflanzenextrakten

Ohne Zusammenfassung     

Mixed Conduction in Tb2O3 Doped BaCeO3

BaxCe0.8Tb0.2O3-a （x=0.98-1.03） solid electrolytes were synthesized and characterized by using X-ray diffraction （XRD）. By using AC impedance spectroscopy and gas concentration cell electromotive force （EMF） measurements, the electrical conduction behavior of the specimens was investigated in different gases during 500-1000 ℃ The influence of nonstoichiometry in the specimens with x ≠ 1 on conduction properties was studied and compared with that in the specimen with x = 1. The results show that the specimens are all of perovskite-type orthorhombic structure. In 500-1000 ℃, electronic hole conduction is dominant in dry and wet oxygen, air or nitrogen. Protonic conduction is dominant in wet hydrogen and it is about two orders of magnitude higher than that in hydrogen-free atmospheres （oxygen, air and nitrogen）. The electrical conductivity of the same specimen in water vapor-saturated oxygen, air or nitrogen is slightly higher than that in corresponding gas without water vapor. The electrical conductivities of the nonstoichiometric specimens are higher than those of the stoichiometric one.     

Photosensitization of trans-Vitamin D3 to cis-Vitamin D3 in Heterogeneous System

Two modes of heterogeneous photoisomerization of trans-vitamin D3 to cis-vitamin D3 are described. The occurrence of isomerization on the substrate bounded to the polymeric support gives us the possibility in succession synthesis of 1α-hydroxyvitamin D3. The polymer-bound anthracene can sensitize isomerization of trans-vitamin D3 to cis-vitamin D3 efficiently and ease the separation process.     

Increase of Calcium Levels at Interphase in NIH 3T3 Cells

The fluorescent calcium ion indicator dye Fluo-3 and DNA-binding dye Hoechst 33342 were employed to determine, in a quantitative microspectrofluorometric study, the intracellular calcium ion concentration ([Ca~(2+)]_i) and the DNA content of individual living NIH3T3 cells. The well-separated excitation and emission properties of these dyes allowed us to establish for each cell both the phase of the cell cycle using DNA content and [Ca~(2+)]_i. We found that the transition from G_1, through S, to the G_2 phase is accompanied by a two-fold increase in [Ca~(2+)]_i. The [Ca~(2+)]_i was inhomologous in each phase of the interphase (G_1, S and G_2) although [Ca~(2+)]_i in the S and G_2 phases was never lower than certain threshold values in the G_1 and S phases respectively. [Ca~(2+)]_i in G_0 cells was lower than that in G_2 cells. These changes in [Ca~(2+)]_i suggest that [Ca~(2+)]_i may be an import regulator of cell cycle progression.     

Reactivity in Air of SbVO5 Towards MoO3 and Phase Equilibria in the SbVO5–MoO3 System in the Solid State

The use of XRD and DTA methods has allowed studies on the interaction of the SbVO₅ and MoO₃, taking place in the solid state and in the medium of ambient air. The experimental results of XRD and DTA for all the samples showed the presence of a novel phase, i.e. Sb₃V₂Mo₃O₂₁ apart from various amounts of MoO₃ and V₉Mo₆O₄₀ or SbVO₅ and V₂O_5(s.s.). The SbVO₅–MoO₃ system is not a real two-component system over the entire range of component concentrations up to the solidus line. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermodynamics of oxygen in CaMnO3 − δ

The experimental data for equilibrium oxygen content were used in order to extract increments of partial molar thermodynamic functions of oxygen with changes of oxygen stoichiometry in calcium manganite CaMnO_3???δ . It is shown that along with the oxygen exchange reaction, thermal excitation of Mn⁴⁺ cations plays an important role in equilibration of charged manganese species that appear in response to the loss of oxygen at heating. The interrelation of partial molar enthalpy and entropy of oxygen with electron and ion defect formation parameters is obtained in approximation of the point defect model. The nearly linear changes of oxygen partial molar enthalpy are shown to directly reflect thermally driven changes in concentration of Mn³⁺ cations.     

Synthesis and phosphorescence properties of Dy3+ and (Pr3+–Dy3+) in MgTiO3

Using tetra-n-butyl titanate and magnesium nitrate as raw materials, Dy³⁺ and Pr³⁺ ions in the matrix of magnesium titanate (MgTiO₃) was successfully synthesized by a modified solid-state reaction. The mixtures to achieve a solid-state reaction were heated in porcelain crucibles at 600?°C for 2?h, 900?°C for 6?h, and 1000.0?°C for 2?h. The reaction products obtained in an air atmosphere were characterized by X-ray powder diffractions. The optimization of reaction conditions were carried out by thermal gravimetry and differential thermal analysis methods. Surface and elemental analyses were performed by using on SEM instrument. The excitation and emission spectra were recorded by photoluminescence spectrophotometer.     

Formation of 3-Arylpyrazolines and 1-Aroylethyl-3-arylpyrazolines via 3-Aroylethylsydnone with HCl in Ethyl Acetate

Hydrolysisofsydnonesbystrongacidtogivesubstitutedhydrazineshasbeendevelopedasaconvenientsynthesisofotherwiseinaccessiblemonoalkylhydrazines'.Bymeansofthiskindofhydrolysis,J.Parricketal.prepared3-hydrazino-4-hydroxy-and3-hydrazino-4-methoxypyridines,whichcouldnotbeobtainedbyreductionofthecorrespondingdiazoniumsalts2.Furthermore,startingwith4-alkyl-3-arylsydnone,Yashunskiietal.obtaineda-formylarylhydrazine'.AccordingtoM.Y.Yeh'sreport,3-aryl-4-halosydnonecouldbeturnedintoa-haloformalarylhydrazi…     

Cyclin A-Cdk2 Phosphorylates BH3 only Protein Bad in vitro and in vivo

Increasing evidence suggests that Cyclin A-Cdk2 activity is required in the apoptosis process induced by various stimuli. To determine a specific substrate of Cyclin A-Cdk2 for apoptosis, in this study, we carried out anin vitro kinase assay using immunoprecipitated complex Cyclin A-Cdk2 as an enzyme source, and recombinant protein GST-Bad as a substrate. Our study showed that Bad was clearly phosphorylated by Cyclin A-Cdk2 in vitro. To examine whether protein Bad can also be phosphorylated by Cyclin A-Cdk2 kinase in vivo, we transiently overexpressed protein Bad with Cyclin A or Cdk2-dn, a dominant negative version of Cdk2, in Hela cells and determined the phosphorylation status of protein Bad. The test showed that protein Bad was clearly phosphorylated in Cyclin A overexpressed cells,but not in Cdk2-dn or mock transfectent. Moreover, etoposide also caused the phosphorylation of endogenetic Bad. In conclusion, here we provide first time evidence that protein Bad can be a substrate of Cyclin A-Cdk2 apoptosis for in vitro and in vivo.     

Site-selective spectroscopy in Eu3+ doped α-cordierite

The location of Eu³⁺ in α-cordierite, synthesized by a sol-gel route, was investigated by using both site-selective spectroscopy and time-resolved spectroscopy. ⁷F₀ → ⁵D_1,2 excitation and ⁵D₀ → ⁷F_0,1,2 emission spectra were performed at 77 K. The Eu³⁺ ions are distributed in two families : the A family in the structure channels and the B family at (4c) position of D_2h¹⁶ in substitution for Mg²⁺ Four B sub-families were characterized and understood as a difference at the second neighbours, i.e., the four possible occupations of the surrounding tetrahedra by Al and Si. The A family was characterized by anomalous spectra: strong ⁵D₀ → ⁷F₀ transition, high position of the ⁵D₀, ⁵D₁ and ⁵D₂ levels and very large ⁷F_1,2 splittings. By comparison with Eu-doped apatites, in which similar features occur, a predominant Eu-O bonding of covalent character with one of the oxygen ions bordering the channel was assumed. When the annealing temperature increases, Eu³⁺ ions migrate from the channel to the (4c) position.     

Phase Equilibria in the System Fe2O3–V2O5 –WO3 in the Solid State

DTA and X-ray phase diffraction methods were used to construct a solidus area projection onto the component concentration triangle plane of the system Fe₂ O₃-V₂ O₅-WO₃. This revised version was published online in August 2006 with corrections to the Cover Date.     

Analysis of the ν2 :ν3 + ν4 Fermi resonance in CH3CN isotopic species in solution

Infrared bands due to ν₃ + ν₄, ν₂, ν₃ and ν₄ were recorded for the species CH₃CN, ¹³CH₃CN, CH₃¹³CN and CH₃C¹⁵N in the solvents carbon tetrachloride, chloroform, benzene, pyridine and dimethyl sulphoxide. Values of W₂₃₄ were extracted by the modified Winther method, which are slightly less, 11.2–11.9 cm⁻¹, than the value in the gas, 12.15 cm⁻¹. Relative intensity measurements of ν₃ + ν₄ and ν₂ in CCl₄ are compatible with an unperturbed intensity ratio, I_{ν3 + ν4}/ I_ν2 of ∼ 0.03. The fallibility of the infrared intensity method for determining W, and the need for precise frequency data in the Winther method, are stressed.     

Defects in Tm^3＋／Yb3＋—doped YVO4 Crystals

<正>The microscopic defects have been investigated for crystal Tm3+/Yb3+:YVO4. These defects mainly include the inclusions (solid inclusions, bubbles and inclusions of the liquid phase), dendrites and growth stripes. They are caused by in-pure raw materials, unstable growth conditions, super-cooling component and so on. Tm3+/Yb3+:YVO4 crystals of large size and excellent optical quality are grown by improving the growth conditions to eliminate these defects.     

Modelling zwitterions in solution: 3-fluoro-γ-aminobutyric acid (3F-GABA)

The conformations and relative stabilities of folded and extended 3-fluoro-γ-aminobutyric acid (3F-GABA) conformers were studied using explicit solvation models. Geometry optimisations in the gas phase with one or two explicit water molecules favour folded and neutral structures containing intramolecular NH···O-C hydrogen bonds. With three or five explicit water molecules zwitterionic minima are obtained, with folded structures being preferred over extended conformers. The stability of folded versus extended zwitterionic conformers increases on going from a PCM continuum solvation model to the microsolvated complexes, though extended structures become less disfavoured with the inclusion of more water molecules. Full explicit solvation was studied with a hybrid quantum-mechanical/molecular-mechanical (QM/MM) scheme and molecular dynamics simulations, including more than 6000 TIP3P water molecules. According to free energies obtained from thermodynamic integration at the PM3/MM level and corrected for B3LYP/MM total energies, the fully extended conformer is more stable than folded ones by about -4.5 kJ mol(-1). B3LYP-computed (3)J(F,H) NMR spin-spin coupling constants, averaged over PM3/MM-MD trajectories, agree best with experiment for this fully extended form, in accordance with the original NMR analysis. The seeming discrepancy between static PCM calculations and experiment noted previously is now resolved. That the inexpensive semiempirical PM3 method performs so well for this archetypical zwitterion is encouraging for further QM/MM studies of biomolecular systems.     

Stabilization of Guanidinate Anions [CN3]5− in Calcite-Type SbCN3

The stabilization of nitrogen-rich phases presents a significant chemical challenge due to the inherent stability of the dinitrogen molecule. This stabilization can be achieved by utilizing strong covalent bonds in complex anions with carbon, such as cyanide CN⁻ and NCN²⁻ carbodiimide, while more nitrogen-rich carbonitrides are hitherto unknown. Following a rational chemical design approach, we synthesized antimony guanidinate SbCN₃ at pressures of 32–38 GPa using various synthetic routes in laser-heated diamond anvil cells. SbCN₃, which is isostructural to calcite CaCO₃, can be recovered under ambient conditions. Its structure contains the previously elusive guanidinate anion [CN₃]⁵⁻, marking a fundamental milestone in carbonitride chemistry. The crystal structure of SbCN₃ was solved and refined from synchrotron single-crystal X-ray diffraction data and was fully corroborated by theoretical calculations, which also predict that SbCN₃ has a direct band gap with the value of 2.20 eV. This study opens a straightforward route to the entire new family of inorganic nitridocarbonates.     

Hauptgruppenelemente in carbonylmetallclustern III. Rutheniumcluster mit μ3-S- und μ3-PR-Einheiten

The trinuclear ruthenium cluster (μ₃-S)(μ₃-PR)Ru₃(CO)₉ (R = C₆H₅) is obtained by reaction of the thioxophosphorane RP(S)Cl₂ with Ru₃(CO)₁₂ in the presence of activated magnesium with cleavage of the PS bond.     

S-Adenosyl-L-methionine ameliorates TNF��-induced insulin resistance in 3T3-L1 adipocytes

An association between inflammatory processes and the pathogenesis of insulin resistance has been increasingly suggested. The IκB kinase-β (IKK-β)/ nuclear factor-κB (NF-κB) pathway is a molecular mediator of insulin resistance. S-Adenosyl-L-methionine (SAM) has both antioxidative and anti-inflammatory properties. We investigated the effects of SAM on the glucose transport and insulin signaling impaired by the tumor necrosis factor α (TNFα) in 3T3-L1 adipocytes. SAM partially reversed the basal and insulin stimulated glucose transport, which was impaired by TNFα. The TNFα-induced suppression of the tyrosine phosphorylation of the insulin receptor substrate-1 (IRS-1) and Akt in 3T3-L1 adipocytes was also reversed by SAM. In addition, SAM significantly attenuated the TNFα-induced degradation of IκB-α and NF-κB activation. Interestingly, SAM directly inhibited the kinase activity of IKK-β in vitro. These results suggest that SAM can alleviate TNFα mediated-insulin resistance by inhibiting the IKK-β/NF-κB pathway and thus can have a beneficial role in the treatment of type 2 diabetes mellitus.     

Bioevaluation of 99mTc(CO)3–Guanine in vitro and in vivo

The aim of this study is to examine biological behaviour of radiolabeled guanine with [Tc(CO)₃]⁺ core in vitro and in vivo. In vitro biological behavior of ^99mTc(CO)₃–Gua was evaluated on Lung (A-549), Breast (MCF-7), Colonic (Caco) carcinoma cell lines and normal human bronchial epithelial (NHBE). ^99mTc(CO)₃–Gua compound showed high uptake on A-549 cell line when compared to NHBE cell line. Biodistribution characteristics of ^99mTc(CO)₃–Gua was evaluated using New Zeland Rabbits. Scintigraphic results showed that a high level of radioactivity was observed in the lungs and liver shortly after administration of the ^99mTc(CO)₃–Gua and excretion takes place via both renal and hepatobiliary route. It was concluded that ^99mTc(CO)₃–Gua could be used as a nucleotide radiopharmaceutical for imaging purposes.