Nepethalates A and B: Two New Phthalate Derivatives from Nepeta clarkei

The structure elucidation of two new phthalate derivatives named nepethalates A ( 1 ) and B ( 2 ) is reported. Both of these secondary metabolites were isolated from the MeOH extract of Nepeta clarkei. HR‐EI‐MS, IR and UV absorption spectrometry, and NMR experiments including COSY, HMQC, and HMBC were used for the determination of the structures and complete ¹H‐ and ¹³C‐NMR assignments.     

Ajuganane: a new phenolic compound from Ajuga bracteosa

Phytochemical investigation of Ajuga bracteosa Wall ex Benth. (Labiatae) resulted in the isolation of a new phenolic compound, ajuganane (1) and three known compounds, 3,4'-dihydroxy-3,6,7-trimethoxyflavone, 7-hydroxy-3,6,3',4'-tetramethoxyflavone and ursolic acid. The structure of the new compound was elucidated by detailed spectroscopic (1H, 13C NMR, COSY, HMQC, HMBC), and HR-EI-MS analysis.     

Distributed feedback grating fabricated from hybrid polymer precursor gel by employing short‐pulse laser interference for photopumped polymer laser applications

The application of hybrid polymer precursor gel for distributed feedback (DFB) grating laser fabricated by short‐pulse laser interference has been investigated. The precursor gel was prepared by sol–gel process from siloxane‐modified methacrylate monomer. The molecular structure characterization results show the formation of inorganic networks within the precursor gel, which further undergoes the formation of organic–inorganic polymer network by photopolymerization. The laser interference was performed by using the frequency‐tripled output of nanosecond Nd–YAG laser. The fabricated DFB gratings exhibit photopumped lasing actions with high consistency between the grating periodicity (between 380 and 1030 nm) and the lasing wavelength, which appears at the wavelength of the second‐order Bragg reflection. The atomic force microcopy measurements clearly show the formation of surface relief (corrugated) structure in those gratings. The mechanism of surface relief formation is attributed to a fast photo‐induced swelling process, which is unique property belonging to this kind of hybrid polymer precursor gel. Copyright © 2011 John Wiley & Sons, Ltd.     

Antituberculosis and cytotoxic activities of triorganotin(Ⅳ) complexes

Five triorganotin（Ⅳ）（1-5） complexes of cinnamic acid.（Z）-2-acetamido-3-phenylacrylic acid,3-methylbut-2-enoic acid,and 2,2-diphenylacetic acid have been synthesized and characterized by ¹H-¹³C-¹¹⁹Sn NMR,UV,and IR.The spectroscopic investigation demonstrated that the carboxylate group acts as a monodentate ligand in triorganotin（IV） compounds.Five triorganotin（Ⅳ） complexes were screened against the log phase culture of Mycobacterium tuberculosis H37Rv by colorimetric method using XTT dye as growth indicator.The MICs were found to be 0.08 and 1.25μg/mL.     

A hybrid forces Quantum Mechanical Charge Field Molecular Dynamics of Cs+ ion in aqueous ammonia: A solvation lability, “structure breaking” phenomenon and hydrogen bond properties

The dynamics and structure of Cs⁺ solvation in an aqueous ammonia solution have been investigated using the Quantum Mechanical Charge Field Molecular Dynamics (QMCF-MD) simulation method. The system contained 18.6% ammonia in aqueous solution at 298.15 K. The QM region was set to a radius of 7.0 Å to include the first and second solvation shells. The Hartree-Fock (HF) level was applied to calculate the ion-ligand and ligand–ligand interactions in the QM region using the LANL2DZ-ECP basis set for the ion and DZP-Dunning for the ligands. The radial distribution revealed only one solvation shell, indicating a labile solvation structure. The various coordination number of ligands suggests an instant exchange between them. The mean residence times of 1.29 and 0.9 ps were less than in the pure water and liquid ammonia system, indicating higher mobility ligands of the aqueous ammonia system. The preferential factor 0.55 supports the hypothesis that the Cs⁺ ion prefers to be dissolved in water. As the ligands moves further away from the ion, the observed number of hydrogen bonds increases, revealing the “structure-breaking” property of the Cs⁺ ion. The minimum angle ligand-ion-ligand tends to be higher near the ion, confirming this phenomenon.     

Improving the performance of solid-state dye-sensitized solar cell using MgO-coated TiO2 nanoporous film

An ultrathin overlayer of MgO on TiO2 is shown to drastically improve the stability of solid-state dye-sensitized solar cell using CuI as a hole conductor in addition to solar energy conversion efficiency.     

Determination of Al,Ca, V and Mn by INAA: Application to the Reference Material IAEA-395 “Urban Dust”

Instrumental NAA based on short-lived radionuclides implies high initial total count rates which change appreciably over the counting period. This in turn necessitates corrections for three negative biases: losses due to differences in counting time between samples and standards; pile-up losses, and (residual) influence of dead-time. The procedure is demonstrated for the determination of Al, Ca, V and Mn in the IAEA Reference Material 395 Urban Dust. The obtained data are in good agreement with the reference values for this material. By limiting the total relative dead-time to 25%, statistical uncertainties are below 5%.     

Correlation of proton MR spectroscopy and diffusion tensor imaging

Proton magnetic resonance spectroscopy ((1)H-MRS) provides indices of neuronal damage. Diffusion tensor imaging (DTI) relates to water diffusivity and fiber tract orientation. A method to compare (1)H-MRS and DTI findings was developed, tested on phantom and applied on normal brain. Point-resolved spectroscopy (T(R)/T(E)=1500/135) was used for chemical shift imaging of a supraventricular volume of interest of 8 x 8 x 2 cm(3) (64 voxels). In DTI, a segmental spin-echo sequence (T(R)/T(E)=5500/91) was used and slices were stacked to reproduce the slab used in MRS. The spatial distributions of choline and N-acetylaspartate (NAA) correlated to mean fractional anisotropy and apparent diffusion coefficient (ADC) for the inner 6 x 6=36 voxels defined in MRS, most notably NAA and ADC value (r=-.70, P<.00001; correlation across four subjects, 144 data pairs). This is the first association of neuron metabolite contents in volunteers with structure as indicated by DTI.     

Phomosines H-J, novel highly substituted biaryl ethers, isolated from the endophytic fungus Phomopsis sp. from Ligustrum vulgare

From the endophytic fungus Phomosis sp., four known phomosines A-D (1-4) and three new phomosines H-J (5-7) have been isolated. The structures of the new compounds were determined on the basis of their spectroscopic data analysis (1H, 13C, 1H-1H COSY, HMQC, and HMBC NMR, as well as mass spectrometry). The structures of phomosine H (5) and J (7) were also confirmed by semisynthesis from phomosine A (1). The remaining four known compounds [phomosines A-D (1-4)] were identified by comparing their spectroscopic data with those reported in the literature. The four known metabolites were biologically active. Of the novel metabolites, only 6 was antifungal and antibacterial.