Demonstration of a nanoparticle-based optical diode

We present the operation of an optical device that exhibits diodelike properties based on two adjacent layers of quantum dots (QDs) encased in a fiber-optic jacket. The possibility of a multilayered device is also discussed. A significant change in the emission spectrum of CdSe/ZnS core-shell QDs was observed when excited by the input laser and the fluorescence of other CdSe/ZnS core-shell QDs. The output of the diode can be taken to be either the incoming laser wavelength of light similar to a conventional diode, or the output may be considered to be one of the QD fluorescence wavelengths. Current work has applications in biological fluorescence monitors and sensors as well as in telecommunications applications.     

Electronic structure and optical properties of isolated and TiO2-grafted free base porphyrins for water oxidation: A challenging test case for DFT and TD-DFT

Seven free base porphyrins employed in dye-sensitized photoelectrosynthetic cells are investigated with the aim of benchmarking the ability of different density functional theory (DFT) and time-dependent DFT approaches in reproducing their structure, vertical, and E_0-0 excitation energies and the energy levels alignment (red-ox properties) at the interface with the TiO₂. We find that both vertical and E_0-0 excitation energies are accurately reproduced by range-separated functionals, among which the ω B97X-D delivers the lowest absolute deviations from experiments. When the dye/TiO₂ interface is modeled, the physical interfacial energetics is only obtained when the B3LYP functional is employed; on the other hand, M06-2X (54% of exchange) and the two long-range corrected approaches tested (CAM-B3LYP and ω B97X-D) excessively destabilize the semiconductor conduction band levels with respect to the dye's lowest unoccupied molecular orbitals (LUMOs), predicting no pathway for electron injection. © 2019 Wiley Periodicals, Inc.     

Chemical destabilization of oil-in-water emulsion by novel polymerized diethanolamines

The main objective of this study was to synthesize novel demulsifiers for resolving oil-in-water emulsions. Diethanolamine polyethers are considered as a cationic polymer type. The study describes an improved synthesis of a series of diethanolamine polyethers via condensation of 3-7 or 9 mol of diethanolamine. The structure and the molecular weights of the major components in the reaction mixture were confirmed via IR and MS analyses. The demulsifiers were used for treatment of pollution in the refinery wastewater with or without FeCl3. The flocculation efficiency of the synthesized demulsifiers was determined by turbidity measurement of the treated and untreated O/W emulsion in the Cairo Oil Refinery Company. The critical flocculation concentration (CFC) and charge density of the synthesized demulsifiers were determined. Biodegradation of diethanolamine polyethers was measured in river water within 7-8 days.     

Integrals involvingE-functions and Kampe de Feriet's functions of higher order

Summary An integral involving the product of three generalised hypergeometric functions is evaluated in terms of Kampe de Feriet's functions of higher order. Infinite integrals involving products of 3, 4, 5 and six Bessel functions are deduced as particular cases. Entrata in Redazione il 1 febbraio 1970.     

Two-wavelength and power-balanced oscillation of a CO2 laser for application to differential absorption measurements

A new technique of alternate two-wavelength oscillation of a CO₂ laser is discussed for application to various differential absorption spectroscopic measurements. Power-balanced, two-adjacent branch oscillation using a single CO₂ laser was achieved by modulating the angle of a mirror inside the laser cavity and adjusting automatically the cavity length. The two-wavelength modulation frequency was extended up to about 1.2 kHz. Line tuning and power modulation characteristics were studied. The laser was used in long-path differential absorption measurements of ethylene air pollution molecules to demonstrate the capability of this power-balanced, two-wavelength oscillation method. The minimum detectable absorption was nearly 1×10^–3 in a short-path cell experiment and 3×10^–3 in a long-path experiment.     

Studies on 5-aminoisoxazole derivatives: Synthesis of some new fused isoxazoles

Several new fused isoxazole derivatives could be obtained utilising 5-amino-4-ethoxycarbonyl-3-ethoxycarbonylmethyl and 5-amino-4-cyano-3-trichloromethyl-isoxazoles as starting components.

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Untersuchungen an 5-Aminoisoxazol-Derivaten: Synthese einiger neuer kondensierter Isoxazole

Zusammenfassung Es konnten einigen neue Isoxazolderivate über 5-Amino-4-ethoxycarbonyl-3-ethoxycarbonylmethyl-und 5-Amino-4-cyano-3-trichlormethyl-isoxazol als Ausgangsverbindungen erhalten werden.

     

Detection and semiquantitative determination of cadmium and copper using polyurethane foam loaded with selective reagents

Polyurethane foams immobilizing dithizone and lead diethyldithiocarbamate were prepared and examined, respectively, for the detection of cadmium and copper in aqueous solution. In batch tests, amounts as low as 0.1 and 0.05 μg ml^?1 of cadmium and copper are easily detected. Lower concentrations of these metal ions were detected in flow experiments using columns packed with 0.5 g of the reagent foam. Semiquantitative determination of these metals is also possible using a suitable standard color scale.     

Structure of macrocyclic alkaloids, oncinotin and isoocinotin

Two new macrocyclic alkaloids oncinotine ( 1 ) and isooncinotine ( 2 ) have been isolated from Oncinotis nitida BENTH . 1 can be converted into 2 by an amide exchange reaction. The spermidine residue was present in both bases. The structural elucidation was based mainly on (I) the determination of the functional groups, (II) degradation to compounds 12 and 13 and (III) mass spectrometric investigation of 1 and of the above mentioned degradation products.     

The profound influence of a single metal-carbon bond on the reactivity of bio-relevant cobalt(III) complexes

This Perspective reports the development of mechanistic insight over the past 6 years, on the substitution behaviour of cobalamins that contain a single Co-C bond. The effect of the alkyl group, located in the trans position, on the thermodynamic, kinetic and ground state trans effect, was studied in detail. The substitution reactions of different alkylcobalamins with CN- were investigated, the apparent mechanistic discrepancy reported for the co-enzyme B12 was resolved and a logical explanation could be offered. In addition, a complete picture of the effect of pressure on the UV-Vis spectra of different base-on and base-off cobalamins is presented, which clearly shows the role of the alkyl group in controlling the equilibrium between five- and six-coordinate species, and the possible participation of such species in the studied ligand substitution reactions. The kinetics of the base-on/base-off equilibration was studied for the first time using a pH-jump technique. All in all the novel mechanistic information adds to the understanding of the profound effect that a single metal-carbon bond can have on the reactivity of such Co(III) complexes.