Photokilling Squamous Carcinoma Cells SCCVII with Ultrafine Particles of Selected Metal Oxides

The ability of ultrafine particles of TiO₂, WO₃ and iron-doped TiO₂ to kill cancer cells in the presence of UV irradiation was investigated. The best photokilling effect on carcinoma cells SCVII cultured in vitro showed iron-doped TiO₂ ultrafine particles synthesized by the sol-gel procedure with starting chemicals Ti(IV)-isopropoxide and anhydrous Fe(II)-acetate. It was found that a small particle size and high dispersity influenced citotoxicity and photocatalytic efficiency. The remarkable photokiling effect of highly iron-doped TiO₂ ultrafine particles (the molar ratio Fe/Ti = 0.136) in the presence of UV irradiation was observed. The influence of ultrafine metal oxide particles on the inhibition of cancer cell proliferation was measured using a ³H-thymidine incorporation test. The possible mechanism involved in the photokilling of carcinoma cells with ultrafine particles of selected metal oxides was discussed.     

Synthesis of new two-photon absorbing fluorene derivatives via Cu-mediated Ullmann condensations

The Ullmann amination reaction was utilized to provide access to a number of fluorene analogues from common intermediates, via facile functionalization at positions 2, 7, and 9 of the fluorene ring. Through variation of amine or iodofluorene derivative, analogues bearing substitutents with varying electron-donating and electron-withdrawing ability, e.g., diphenylamino, bis-(4-methoxyphenyl)amine, nitro, and benzothiazole, were synthesized in good yield. The novel fluorene derivatives were fully characterized, including absorption and emission spectra. Didecylation at the 9-position afforded remarkably soluble derivatives. Target compounds 4, 5, and 9 are potentially useful as fluorophores in two-photon fluorescence microscopy. Their UV-vis spectra display desirable absorption in the range of interest suitable for two-photon excitation by near-IR femtosecond lasers. Preliminary measurements of two-photon absorption indicate the derivatives exhibit high two-photon absorptivity, affirming their potential as two-photon fluorophores. For example, using a 1,210 nm femtosecond pump beam, diphenylaminobenzothiazolylfluorene 4 exhibited nondegenerate two-photon absorption, with two-photon absorptivity (delta) of ca. 820 x 10(-50) cm(4) s photon(-1) molecule(-1) at the femtosecond white light continuum probe wavelength of 615 nm.     

Use of dynamically coated capillaries with added cyclodextrins for the analysis of opium using capillary electrophoresis

A rapid, precise, accurate, and robust method using capillary electrophoresis (CE) with dynamically coated capillaries for the analysis of the major opium alkaloids in opium is presented. Dynamic coating of the capillary surface is accomplished using a commercially available reagent kit (polycation coating followed by polyanion coating). The addition of dual cyclodextrins (hydroxypropyl-beta-cyclodextrin and dimethyl-beta-cyclodextrin) to the run buffer imparts excellent selectivity for the opium alkaloids. For the determination of morphine, papaverine, codeine, noscapine and thebaine in opium gum and opium latex samples (using tetracaine as an internal standard) good agreement with values obtained by gradient high-performance liquid chromatography is obtained. Compared to the latter technique, CE affords better resolution with significantly faster analysis time (12 min versus 29 min). Dynamically coated capillaries, which give rise to a relatively high and robust electroosmotic flow (EOF) at the background electrolyte pH of 2.5, allow for rapid analysis and excellent migration time and peak area precision (RSDs < or = 0.12% and < or = 1.2%, respectively). Reproducible separations (relative migration times) for over 500 samples have been obtained on a single capillary. The nature of the injection solvent, the injection time and the contents of the waste vials have a profound effect on the pressure injection precision of the relatively hydrophobic solutes. The CE conditions reported in this study are also applicable to the analysis of lysergic acid diethylamide (LSD) exhibits.     

Charge-transfer complexes of indenophanes with π-acceptors

The charge-transfer (CT) spectra of the -complexes formed by a number of -acceptors with several indenophanes as well as indene as a model compound have been measured in methylene chloride at 20 °C. Association constants and transition energies of these complexes as well as ionization potentials of the -donors have been determined. The data obtained indicate the existence of transannular electronic interactions in the indenophane nucleus. Furthermore, the pseudo-para- andmeta[2.2]indenophane isomers (3 and4) show a large difference in their -base strength. A good linear relationship has been observed between the association constants and _max of the long wavelength CT bands for the -complexes of these -donors with both tetracyanoethylene (TCNE) and 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ). All CT complexes studied have a 1:1 stoichiometry.

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Charge-transfer-Komplexe aus Indenophanen und -Akzeptoren

Zusammenfassung Die Charge-transfer-Spektren (CT-Spektren) von -Komplexen aus Indenophanen bzw. der Modellverbindung Inden und verschiedenen -Akzeptoren wurden in Methylenchlorid bei 20 °C bestimmt. Die Assoziationskonstanten und Übergangsenergien dieser Komplexe sowie die Ionisationspotentiale der -Donatoren wurden ermittelt. Die Daten sprechen für das Vorliegen transannularer elektronischer Wechselwirkungen im Indenophan-System. Die isomeren pseudo-para- und -meta[2.2]indenophane3 und4 unterscheiden sich in ihrer -Basizität deutlich. Es besteht eine gute lineare Korrelation zwischen den Assoziationskonstanten und _max der langwelligen CT-Banden der verschiedenen -Donatoren mit Tetracyanoethylen (TCNE) und 2,3-Dichlor-5,6-dicyano-p-benzochinon (DDQ). Alle untersuchten CT-Komplexe besitzen 1:1-Stöchiometrie.

     

Acid-base sensors based on novel quinone-type dyes

We present a detailed study on the acid-base behaviour of a family of "potentially antiaromatic" p-benzoquinonediimine ligands. These 12pi electron molecules can be considered as constituted of two chemically connected but electronically not conjugated 6pi-electron subunits. Upon successive protonation, "mono" and "double" cyanine-type chromophores are generated in solution and allow a precise and sensitive spectrophotometric detection. These molecules represent a new class of tunable quinones whose electronic and structural properties can be triggered by proton input, as established by a complete physico-chemical study involving a combination of potentiometric and spectrophotometric methods (absorption and emission).     

Characterization by X-ray diffraction, magnetic susceptibility and Mössbauer spectroscopy of a new alluaudite-like phosphate:: Na4CaFe4(PO4)6

A single crystal of a new sodium calcium iron (III) phosphate, Na₄CaFe₄(PO₄)₆, has been synthesized by a flux method and characterized by X-ray diffraction, Mössbauer spectroscopy and magnetic susceptibility measurements. The compound crystallizes in the monoclinic space group C2/c(a=12.099(5) Å, b=12.480(5) Å, c=6.404(2) Å, β=113.77(3)°, Z=2, R₁=0.022, R_w2=0.066). The crystal structure belongs to the alluaudite type, characterized by the X(2)X(1)M(1)M(2)₂(PO₄)₃ general formula. The open framework results from Fe₂O₁₀ units of edge-sharing FeO₆ octahedra, which alternate with M(1)O₆ octahedra (M(1)=Na+Ca) that form infinite chains. These chains are linked together through the common corners of PO₄ tetrahedra yielding two distinct tunnels of sodium cation occupation. This compound is antiferromagnetic with a Néel temperature of 35 K. Mössbauer parameters are consistent with the structural results.     

Transient and steady state creep of Al-4.5 wt.% Mg during phase transformation

Transient and steady state creep of Al-4.5 wt. % Mg alloy was studied under various constant stresses ranging from 91 MPa to 117 MPa in the temperature range from 473 K to 553 K. The results of creep characteristics have shown two main deformation temperature regions (below 493 K and above 513 K as well as a transient region between these temperatures). Peak values of transient creep parametersB andn were obtained at 493 K. The transient creep parameterB was related to the steady state creep rate _st through the exponent which was found to range from 0.85 to 0.5. The stress exponentm of the steady state creep has been found to be minimum at the steady state strain peaks, which is characteristic of dislocation climb along the grain boundaries. Microstructural analysis confirmed that the above mentioned mechanism took place in the dissolution region of-phase.     

Validation of a novel very large eddy simulation method for simulation of turbulent separated flow

The paper describes the validation of a newly developed very LES (VLES) method for the simulation of turbulent separated flow. The new VLES method is a unified simulation approach that can change seamlessly from Reynolds‐averaged Navier–Stokes to DNS depending on the numerical resolution. Four complex test cases are selected to validate the performance of the new method, that is, the flow past a square cylinder at Re = 3000 confined in a channel (with a blockage ratio of 20%), the turbulent flow over a circular cylinder at Re = 3900 as well as Re = 140,000, and a turbulent backward‐facing step flow with a thick incoming boundary layer at Re = 40,000. The simulation results are compared with available experimental, LES, and detached eddy simulation‐type results. The new VLES model performs well overall, and the predictions are satisfactory compared with previous experimental and numerical results. It is observed that the new VLES method is quite efficient for the turbulent flow simulations; that is, good predictions can be obtained using a quite coarse mesh compared with the previous LES method. Discussions of the implementation of the present VLES modeling are also conducted on the basis of the simulations of turbulent channel flow up to high Reynolds number of Re_τ = 4000. The efficiency of the present VLES modeling is also observed in the channel flow simulation. From a practical point of view, this new method has considerable potential for more complex turbulent flow simulations at relative high Reynolds numbers. Copyright © 2013 John Wiley & Sons, Ltd.