Thermoelectrical and optical properties of double wall carbon nanotubes:polyaniline containing boron n‐type organic semiconductors

The electrical conductivity, thermoelectrical, and optical properties of the polyaniline containing boron/double wall carbon nanotubes (CNTs) composites have been investigated. The electrical conductivities of the composites prepared with 1%, 5%, and 8% CNT concentrations at 300 K were found to be 5.31 × 10^?6, 2.72 × 10^?4, and 1.12 × 10^?3 (S/cm), respectively. The thermoelectrical results indicate that all the samples exhibit n‐type electrical conductivity. The optical band gaps of the samples were found to be 3.71 eV for 0% DWNT, 3.32 eV for 1% DWNT, 3.15 eV for 5% DWNT, and 3.12 eV for 8% DWNT. The obtained results suggest that the electrical conductivity of PANI‐B polymer is improved by DWNT doping. Copyright © 2008 John Wiley & Sons, Ltd.     

Spectroscopic characterization of charge-transfer complexes of morpholine with chloranilic and picric acids in organic media: Crystal structure of bis(morpholinium 2,4,6-trinitrocyclohexanolate)

Electron donor–acceptor interaction of morpholine (morp) with chloranilic acid (cla) and picric acid (pa) as π-acceptors was investigated spectrophotometrically and found to form stable charge-transfer (CT) complexes (n–π*) of [(Hmorp)₂(cla)] and [(Hmorp)(pa)]₂. The donor site involved in CT interaction is morpholine nitrogen. These complexes are easily synthesized from the reaction of morp with cla and pa within MeOH and CHCl₃ solvents, respectively. ¹HNMR, IR, elemental analyses, and UV–vis techniques characterize the two morpholinium charge-transfer complexes. Benesi–Hildebrand and its modification methods were applied to the determination of association constant (K), molar extinction coefficient (?). The X-ray crystal structure was carried out for the interpretation the predict structure of the [(Hmorp)(pa)]₂ complex.     

An empirical many-body potential energy function constructed from pair-interactions

A new empirical potential energy function (PEF) is proposed, which is formed from pair-interactions only, and containes the many-body contributions. The PEF satisfies bulk cohesive energy and bulk stability condition. The PEF is parameterized for copper, silver, and gold elements in fcc crystal structure. The elastic constantsC ₁₁ andC ₁₂ and the bulk modulus of the elements are calculated, and the structural stability and energetics of microclusters containing 3 to 7 atoms of the same elements are investigated.     

The infrared spectra and normal coordinate analysis of syn and anti acetaldoxime

The infrared spectra of mixtures of syn and anti acetaldoxime and its deuterated analogues CH₃CHNOD, CD₃CHNOH, CD₃CDNOH and CH₃CDNOH have been recorded. The syn and anti isomers of CH₃CHNOH, CD₃CHNOH, CD₃CDNOH and CH₃CDNOH have been separated by gas chromatography [1]. The infrared spectra of separated isomers in CS₂ solution have been recorded and the assignment of ten in-plane vibrations made. From a normal coordinate analysis the Urey-Bradley force field, the potential energy distribution and additional information about assignments have been obtained.For the anti isomer the simple Urey-Bradley force field gives satisfactory agreement between the calculated and measured frequencies. For the syn isomer it is necessary to take into account the interactions between atoms separated by three bonds.     

Flow injection analysis : Part II. Ultrafast determination of phosphorus in plant material by continuous flow spectrophotometry

The effect of sample volume, tube length, tube diameter, peak height and sampling rate on the determination of phosphorus in acidic plant digests was investigated, and optimal conditions for the flow injection method are described. Sampling rates of 420 samples per hour were achieved without incurring problems from carryover of samples, and evidence was obtained that rates as high as 700 samples per hour are possible. The flow injection method was proved to be suitable for routine analyses and has obvious advantages over other automated or manual methods in sampling rate, simplicity of design and cost.     

New gold(III) chlorophenyl terpyridine complex: Biomolecular interactions and anticancer activity against human oral squamous cell carcinoma

In this work we synthesized new monofunctional gold(III) complex [Au(Cl-Ph-tpy)Cl]Cl₂ (Cl-Ph-tpy = 4′-[4-chlorophenyl]-2,2′:6′, 2″-terpyridine). This complex was characterized by UV–Vis, NMR, IR, and ESI-MS spectrometry. The kinetic study of the substitution reactions of the Au-Cl-Ph-tpy complex with biomolecules showed that the rate constants depend on the nature of the entering nucleophile. Based on the calculated values of entropy (∆H^≠ > 0) and enthalpy (∆S^≠ < 0) the proposed substitution mechanism is associative. Additionally, the relative stability and thermodynamic properties of Au-Cl-Ph-tpy complex were compared with the analogue Au-tpy complex by the B3LYP/def2-svp method. DNA/BSA binding studies showed that Au-Cl-Ph-tpy complex interacts with CT DNA through the intercalation and moderately quenches the fluorescence of tryptophan residues in serum albumin (BSA). Molecular docking confirmed results obtained by spectroscopic experiments and suggested site I (subdomain IIA) for binding of Au complex to BSA. We demonstrated that the Au chlorophenyl terpyridine complex possessed significant in vitro cytotoxic activity against human oral squamous carcinoma cells (CAL-27), induced apoptosis, inhibited proliferation of CAL-27 cells, and induced cell cycle disturbance. Treatment of CAL-27 cells with the Au complex enhanced expression of cyclin-dependent kinase inhibitors p21 and p27, resulting in cell cycle arrest in the G1 phase, reduced the percentage of CAL-27 cells in S phase and decreased expression of Ki-67. Additionally, Au complex reduced expression of phosphorylated STAT3 and downstream regulated molecules associated with cancer stemness, NANOG, and Sox2 protein.     

Use of Uracil Thin Layer for Measuring Biologically Effective UV Dose

Abstract— Dimerization of uracil monomers in a polycrystalline state by UV radiation changes the absorption characteristics of a thin layer of the material. The change in optical density, measured by spectrophotometry in the250–400 nm range, as a function of the exposure time is evaluated in terms of the biologically effective UV dose. A statistical evaluation of a great number of uracil dosimeters irradiated with a TL01 lamp from Philips establishes the possibility of evaluating the biologically effective UV dose using a uracil dosimeter. Nonlinear regression procedures were introduced to correct the absorption spectra for contributions due to light scattering and to determine the optical density values required to calculate the UV dose expressed in H^Uunits. Comparison of cumulative daily doses and long-term monitoring measured by the uracil thin-layer dosimeter and a phage T7 dosimeter are given, which allow the determination of conversion factors between various biological dosimeters under different irradiation conditions.     

Comparing Singlet Oxygen Generation of Schiff Base Substituted Novel Silicon Phthalocyanines by Sonophotochemical and Photochemical Applications

Although the sonophotodynamic method has an effective therapeutic outcome for anticancer treatment compared with the photodynamic method, there are not enough related studies in the literature and this study aims to contribute to the development of sonophotodynamic studies. For this purpose, the Schiff base substituted silicon phthalocyanines were designed and synthesized as effective sensitizer candidates and the photophysicochemical and sonophotochemical features of the phthalocyanines were examined to increase singlet oxygen efficiency. The calculated Φ_Δ values indicate that the contribution of substituent groups improved the production of singlet oxygen compared with silicon (IV) phthalocyanine dichloride (SiPcCI₂) and also the sonophotochemical applications increased the singlet oxygen yields. The Φ_Δ values (Φ_Δ = 0.76 for axially bis-{4-[(E)-(pyridin-3-ylimino)methyl]phenol} substituted silicon (IV) phthalocyanine ( 2a ), 0.68 for axially bis-4-[(E)-{[(pyridin-3-yl)methyl]imino}methyl]phenol substituted silicon (IV) phthalocyanine ( 2b ) in photochemical study) reached to Φ_Δ = 0.98 for 2a , 0.94 for 2b in sonophotochemical study. This article will enrich the literature on increasing singlet oxygen yield.