Fatigue effect in luminescence of glow discharge amorphous silicon at low temperatures

Fatigue in the luminescence was observed in glow discharge amorphous silicon at 4.2 K and 77 K. This fatigue was not recovered by infra-red illumination, but by heating the sample at higher temperatures. These results are interpreted in terms of enhancement of non-radiative recombination associated with dangling bonds created by high optical excitation.     

Spectrophotometric determination of boron in natural waters and rocks after specific adsorption on sephadex gel

Borate ions are adsorbed on Sephadex G-25 gel from alkaline media and desorbed reversibly into acidic media; the adsorption is ascribed to complex formation between borate and glucose units in the gel matrix. The coexistence of large amounts of salts, e.g. sodium chloride, ammonium chloride, sodium sulfate, and sodium perchlorate, has little effect on the adsorption. The effect of cations which form complexes with borate can be eliminated by the addition of EDTA. Boron present, in natural waters and rocks at lowlevels can be selectively concentrated by means of a gel column and determined spectrophotometrically by the azomethine-H method.     

Effect of substrate temperatures and annealing on optically detected magnetic resonance in glow-discharge amorphous silicon

Optically detected magnetic resonance experiments have been performed at 2 K in glow-discharge amorphous silicon with different substrate temperatures. Effects of annealing and illumination on ODMR have been examined. A broad line is interpreted in terms of a three-centre bond model.     

Organic photoconductors. VIII. Photoconductors obtained from the reaction products of poly(9-vinyl anthracene)

9-Vinyl anthracene has been polymerized by three methods in cationic systems to obtain organic photoconductors. Cationic polymerization catalysts used were titanium tetrachloride and aluminum chloride anhydride. According to the degree of conversion from poly(9-vinyl anthracene) to poly(9,10-dimethylene anthracene) the photosensitivity increased.     

Synthesis of Chiral Crownophanes Having Two Phenolic Groups via Tandem Claisen Rearrangement and Their Chiral Recognition

Asymmetric crownophanes having a chiral binaphthyl unit and two phenolic hydroxyl groups were thermally synthesized from the corresponding macrocyclic ethers via tandem Claisen rearrangement. Circular dichroism (CD) spectroscopic studies and HPLC experiments confirmed that little racemization of these crownophanes occurred during the thermal rearrangement. The association constants for the interaction of the chiral crownophanes with the enantiomers of phenylethylamine, phenylglycinol, and phenylalaninol were determined by a ¹H NMR titration method in CD₂Cl₂. As a result, the 27 membered crownophane has some chiral recognition for phenylglycinol.     

Digital holographic PTV for complicated flow in a water by two cameras and refractive index-matching method

Optical Review - A basic heat transfer promoter such as packed beds of spheres is one of the technologies of the promotion of heat transfer using the turbulent mixture. We carried out 3-D...     

Total Synthesis and Functional Evaluation of Fourteen Derivatives of Lysocin E: Importance of Cationic,Hydrophobic, and Aromatic Moieties for Antibacterial Activity

Lysocin E ( 1 ) is a structurally complex 37‐membered depsipeptide comprising 12 amino‐acid residues with an N‐methylated amide and an ester linkage. Compound 1 binds to menaquinone (MK) in the bacterial membrane to exert its potent bactericidal activity. To decipher the biologically important functionalities within this unique antibiotic, we performed a comprehensive structure‐activity relationship (SAR) study by systematically changing the side‐chain structures of l ‐Thr‐1, d ‐Arg‐2, N‐Me‐d ‐Phe‐5, d ‐Arg‐7, l ‐Glu‐8, and d ‐Trp‐10. First, we achieved total synthesis of the 14 new side‐chain analogues of 1 by employing a solid‐phase strategy. We then evaluated the MK‐dependent liposomal disruption and antimicrobial activity against Staphylococcus aureus by 1 and its analogues. Correlating data between the liposome and bacteria experiments revealed that membrane lysis was mainly responsible for the antibacterial functions. Altering the cationic guanidine moiety of d ‐Arg‐2/7 to a neutral amide, and the C7‐acyl group of l ‐Thr‐1 to the C2 or C11 counterpart decreased the antimicrobial activities four‐ or eight‐fold. More drastically, chemical mutation of d ‐Trp‐10 to d ‐Ala‐10 totally abolished the bioactivities. These important findings led us to propose the biological roles of the side‐chain functionalities.