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  • 1
    Electronic Resource
    Electronic Resource
    Concentration of hydrophobic organic compounds and extraction of protein using alkylammoniosulfate zwitterionic surfactant mediated phase separations (cloud point extractions) (1991)
    s.l. : American Chemical Society
    Analytical chemistry 63 (1991), S. 2520-2525 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac00021a023
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  • 2
    Electronic Resource
    Electronic Resource
    Disorder of ZnSe/ZnS strained-layer superlattices by N+ or Li+ ion implantation and low-temperature annealing (1991)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 58 (1991), S. 53-55 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We demonstrate layer disordering of ZnSe/ZnS strained-layer superlattices (SLSs) induced by low-damage N+ or Li+ ion implantation and low-temperature annealing. The interdiffusion of Se and S atoms was observed by secondary-ion mass spectrometry analyses. By reflectance measurements, a significant decrease in the refractive index, which is useful for waveguiding applications, was measured in the disordered SLS. In photoluminescence (PL) spectra, strong excitonic emission around 400 nm was observed in the disordered SLS corresponding to a damage recovery. A slight red shift of the PL peak observed in the early stages of annealing is interpreted as the relaxation of misfit strain by interdiffusion. For longer annealing times, the PL peak for an implanted SLS shifted towards the higher energy side, which clearly indicates layer disordering of the SLSs. This low-temperature planar process will be very useful for the fabrication of II-VI semiconductor optoelectronic devices.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.104442
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  • 3
    Electronic Resource
    Electronic Resource
    Reactive ion beam etching of ZnSe and ZnS epitaxial films using Cl2 electron cyclotron resonance plasma (1990)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 56 (1990), S. 839-841 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Reactive ion beam etching of ZnSe and ZnS epitaxial films was carried out using pure Cl2 as an etching gas. Electron cyclotron resonance plasma was excited at pressures of 2.5×10−4 –2.5×10−3 Torr. Chlorine ions were extracted with voltages of 0–400 V. Sputtering yields were strongly dependent on the extraction voltage and the gas pressure. The etching mechanism starts with the generation of chloride compounds, mainly ZnClx, by the chemical reaction of the surface and chlorine radicals, mainly Cl atoms. The chloride compounds are subsequently sputtered off by the accelerated ion beam. The crystalline quality of etched ZnSe films was characterized by photoluminescence measurements. We found that high quality etched films, which have almost no damage and no Cl contamination, can be obtained at an extraction voltage of about 300 V.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.102678
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  • 4
    Electronic Resource
    Electronic Resource
    Optical characterization of ZnSe/ZnS strained-layer superlattices grown on CaF2 substrates (1991)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 58 (1991), S. 1754-1756 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Growth of ZnSe/ZnS strained-layer superlattices on CaF2 substrates has been demonstrated for the first time. Optical transmission measurements at 77 K were carried out to investigate the optical property of excitons confined in ZnSe/ZnS multiquantum wells. Two exciton peaks related to the transitions between n=1 electron and heavy hole (Ee–hh) and between n=1 electron and light hole (Ee–lh) were observed in the transmission spectra. The energy seperation between Ee–hh and Ee–1h increases with decreasing the ZnSe layer thickness, which is due to the increase of strain in the ZnSe well layer. From the relationship between ZnSe well layer thickness and peak energy, the quantum size effect in the quantum well was also confirmed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.105080
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  • 5
    Electronic Resource
    Electronic Resource
    Disordering of ZnSe/ZnS strained-layer superlattices by Si ion implantation (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 55 (1989), S. 735-737 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Disordering of ZnSe/ZnS strained-layer superlattices(SLSs) induced by Si ion implantation and subsequent low-temperature thermal annealing was confirmed. Si ions were implanted (100 keV, 1×1016 ions/cm2 ) into SLSs (140 A(ring) ZnSe-140 A(ring) ZnS, ten periods). By secondary-ion mass spectrometry analyses, periodic profiles of Se and S were clearly observed just after the ion implantation; however, they disappeared after subsequent thermal annealing (450 °C, 3 h). Photoluminescence measurements showed the peak of ZnSx Se1−x alloyed crystal after thermal annealing. The disordering is mainly induced by the diffusion of defects generated by the ion implantation at the early stage of low-temperature thermal annealing. This low temperature and planar process will be very useful to the fabrication of II-VI compound semiconductor optical and electrical devices.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.101790
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  • 6
    Electronic Resource
    Electronic Resource
    Distribution of metal chelates between aqueous and surfactant phases separated from a micellar solution of a nonionic surfactant (1992)
    Springer
    Microchimica acta 106 (1992), S. 83-90 
    Details
    ISSN: 1436-5073
    Keywords: distribution equilibrium ; chelating reagents ; metal chelates ; micellar solution ; poly (oxyethylene) 4-nonylphenyl ether
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A dilute micellar solution of poly(oxyethylene) 4-nonylphenyl ether with oxyethylene units 7.5 (PONPE-7.5) was separated into two phases (aqueous and surfactant phases) at room temperature. The partition constants of several chelating reagents and their metal chelates between the two phases were determined at 293 K and ionic strength 0.1 (NaClO4). The partition constants of the neutral metal chelates depend on the kind of metal ions and were considerably smaller than those expected from the regular solution theory. These facts suggested that the chelates were incorporated into a hydrocarbon environment in the surfactant phase, whereas the chelating reagents were distributed in the poly(oxyethylene) part of PONPE-7.5. A brief review was also presented on the analytical applications to the extraction of metal ions and organic compounds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01242702
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  • 7
    Electronic Resource
    Electronic Resource
    Solute partition study in aqueous sodium dodecyl sulfate micellar solutions for some organic reagents and metal chelates (1992)
    Springer
    Microchimica acta 106 (1992), S. 91-99 
    Details
    ISSN: 1436-5073
    Keywords: sodium dodecyl sulfate ; micelles ; partition constants ; organic reagents ; metal chelates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The partition constants (K d) have been estimated for nitrophenols, thiazolylazo dyestuffs and metal chelate compounds into the sodium dodecyl sulfate (SDS) micellar phase at an ionic strength of 0.10M [(H+, Na+)Cl−] and at 20 °C. The equilibrium partition data obtained by batch-wise solution spectrophotometry (equilibrium shift method) agree well with those by the micellar electrokinetic capillary chromatography (MECC) with the SDS micellar pseudo-stationary phase. The MECC clearly discriminates a very small difference (0.03) in the logK d values of some metal chelates. The plot of theK d values with the van der Waals volume of the solute molecules obviously shows the leveling-off of theK d values over solute size near 110 ml/mol, which seems to be consistent with the results obtained in the Triton X-100 micellar system. This phenomenon arises most probably from the rigidity of the micellar pseudo-phase (a micellar volume-constraint effect) in sharp contrast with true two-phase partitioning such as solvent extraction systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01242703
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  • 8
    Electronic Resource
    Electronic Resource
    Polymer-induced phase separation in aqueous micellar solutions of octyl-β-D-thioglucoside for extraction of membrane proteins (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 56 (1997), S. 311-318 
    Details
    ISSN: 0006-3592
    Keywords: micelle ; water-soluble polymer ; protein extraction ; phase separation ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A water-soluble polymer such as polyethylene glycol (PEG), Dextran T-500 (Dx), or diethylaminoethyl-Dextran (DEAE-Dx) induced aqueous micellar solutions of octyl-β-D-thioglucoside (OTG) to phase separation at 0°C. One of the two phases thus formed is a surfactant-depleted aqueous solution (aqueous phase) of a water-soluble polymer and the other a concentrated OTG solution (surfactant-rich phase). In a combination of OTG with PEG or Dx, cytochrome P450 (P450) and cytochrome b5 (b5) were well extracted into the surfactant-rich phase. The extraction yield of P450 was slightly greater than that of b5. In contrast to PEG and Dx, DEAE-Dx markedly reduced the extraction of b5, while that of P450 remained almost unchanged. DEAE-Dx served the dual functions of inducing the phase separation and preventing the extraction of b5 into the surfactant-rich phase. This depressed extraction of b5 was reversed by the addition of potassium phosphate. DEAE-Dx and potassium phosphate proved effective in controlling the extractability of b5. The polymer-induced phase separation provides a new basis for highly efficient extraction of membrane proteins under mild conditions that should be acceptable for thermolabile membrane proteins under physiological conditions. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 56: 311-318, 1997.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Cytotoxicological aspects of organic arsenic compounds contained in marine products using the mammalian cell culture technique (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 137-143 
    Details
    ISSN: 0268-2605
    Keywords: arsenobetaine ; arsenocholine ; trimethylarsine oxide ; tetramethylarsonium iodide ; organic arsenic compound ; arsenite ; arsenate ; marine organisms ; cytotoxicity ; chromosomal aberration ; sister chromatid exchange (SCE) ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Arsenobetaine, arsenocholine, trimethylarsine oxide and tetramethylarsonium iodide, which are contained in marine fishery products, were examined for their potencies on cell growth inhibition, chromosomal aberration and sister chromatid exchange (SCE). Arseno- betaine, the major water-soluble organic arsenic compound in marine animals, exhibited very low cytotoxicity towards mammalian cells. This compound showed no cell growth inhibition at a concentration of 10 mg cm-3 and the cytotoxicity was lower than 1/14 000th of that of sodium arsenite and 1/1600th of that of sodium arsenate towards BALB/c 3T3 cells. The chromosomal aberrations caused by arsenobetaine at a concentration of 10 mg cm-3 consisted mainly of chromatid gaps and chromatid breaks, but in this concentration chromosomal breakage owing to its osmotic pressure is likely to be considerable. No SCE was observed at a concentration of 1 mg cm-3. Arsenocholine and trimethylarsine oxide also showed no cell growth inhibited at a concentration of 10 mg cm-3. However, tetramethylarsonium iodide inhibition the growth of BALB/c 3T3 at a concentration of 8 mg cm-3. These compounds exhibited a low ability to induce chromosomal aberrations at a concentration range of 2-10 mg cm-3 and no SCE was observed at a concentration of 1.0 mg cm-3. These results suggested that the major and minor organic arsenic compounds contained in marine fishery products are much less cytotoxic inorganic arsenic, methylarsonic acid and dimethylarsinic acid. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 2 Ill.
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  • 10
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    Optical characterization of ZnSe/ZnS strained‐layer superlattices grown on CaF2substrates (1991)
    American Institute of Physics
    Details
    Publication Date: 1991-04-22
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Published by American Institute of Physics
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