SPONTANEOUS LOW-LEVEL CHEMILUMINESCENCE FROM CHEMICAL AND ELECTROCHEMICAL OXIDATION OF β-DEHYDRO NICOTINEAMIDE ADENINE DINUCLEOTIDE

Abstract— Oxidation of β-dehydro nicotineamide adenine dinucleotide (NADH) by oxygen catalyzed by horseradish peroxidase was accompanied by spontaneous, low-level chemiluminescence in the existence of co-oxidant 2,4-dichlorophenol. Electrochemical oxidation of NADH by the glassy carbon electrode also emitted a spontaneous low-level chemiluminescence above the potental +0.7 V vs reference electrode (Ag/AgCl) in aqueous medium in pH 7.0˜10.0. Low-level electrochemilumin-escence was observed when the NAD and oxygen species coexisted in the neighborhood of the electrode surface. The main photon emission process was supposed to be generated by the interaction of pyridine moiety of NAD and oxygen.     

OSCILLATORY LOW-LEVEL CHEMILUMINESCENCE FROM A NONEQUILIBRIUM β-NICOTINAMIDE ADENINE DINUCLEOTIDE-PEROXIDASE SYSTEM: EXPERIMENTAL OBSERVATIONS and COMPUTER SIMULATIONS

Using a highly sensitive photon counting technique, oscillatory low-level chemiluminescence was observed from a non-equilibrium oxidation of β-nicotinamide adenine dinucleotide (NADH) by horseradish peroxidase (HRP). Emergence and stability of the oscillation were affected by the concentration of HRP, 2,4-dichlorophenol and infusion rate of NADH. We also constructed a simultaneous rate equation to explain the oscillatory phenomena of this non-equilibrium system, in which the photon emission was assumed to be generated from NAD'-O₂ interaction.     

Phase-locked widely tunable optical single-frequency generator based on a femtosecond comb

We present an arbitrary optical single-frequency generator based on a femtosecond optical frequency comb. The functions of this device are comparable to those of a radio-frequency synthesizer. However, this device operates at hundreds of terahertz. The absolute frequency accuracy of this synthesizer is approximately 1 kHz at a 282 THz carrier frequency. The stability is approximately 2 x 10(-14) at 100 s, and the tuning speed exceeds 30 GHz/s. This source demonstrates the integration of a phase-locked optical comb into a versatile and easy-to-use system for the generation of tunable, absolute optical frequencies. By using downconversion, one could generate tunable terahertz frequencies that are phase locked to a microwave reference, such as a Cs atomic clock, and high-precision interferometry could benefit greatly from the stability and accuracy of this widely tunable source.     

Lasing action of active-particles dispersed in microdroplets and its enhanced characteristics by highly scattering intralipid-10% mixture

The first laser action of active-particles of 1–2 m in diameter, red fluorescent-powder (FP), dispersed in nonactive (nonlasing) 100 m-sized liquid microdroplets is reported. Lasing characteristics of FP-containing microdroplets by mixing Intralipid-10% as highly scattering turbid media are also described. Well-defined lasing thresholds can be confirmed from the FP-dispersed pure microdroplets, and lowered lasing threshold along with enhanced lasing emission is achieved by appropriately mixing the Intralipid-10% solution. Lasing threshold in these microdroplets can be determined not through the spectral narrowing features but through the input–output data. We believe that these new microdroplet configurations offer one of the new categories of lasing media and they seem also to simulate to some biological pigments or organelles contained in cells and small tissues.     

Doubly resonant photon echoes in a three-level system

This paper deals with the photon echoes associated with two optical pulses of different frequencies, resonant to a three-level system, and reveals the existence of anomalous echoes, appearing at times corresponding to the correlations between the inhomogeneous broadenings for different spectral lines. The intensities, direction of propagation and polarizations of the echoes are analyzed quantitatively.     

Atomic force microscopy study on the stability of a surface film formed on a graphite negative electrode at elevated temperatures

The stability at elevated temperatures of a solid electrolyte interphase (SEI) formed on a graphite negative electrode in lithium ion batteries was investigated by storage tests and in situ atomic force microscopy (AFM) observation. When the fully discharged graphite electrode was stored at elevated temperatures, the irreversible capacity in the following cycle increased remarkably. On the other hand, when the electrode was stored at the fully charged state at elevated temperatures, it was severely self-discharged during storage. AFM observation of the SEI layer formed on a model electrode of highly oriented pyrolytic graphite revealed two important facts on the stability of the SEI at elevated temperatures: (i) dissolution and agglomeration of the SEI layer at the discharged state and (ii) serious SEI growth at the charged state. These phenomena well explain the results of the charge and discharge tests. It was also shown that the addition of vinylene carbonate greatly improves the stability of the SEI at elevated temperatures, and gives good charge and discharge performance after storage.     

On a Theorem of Childs on Normal Bases of Rings of Integers: Addendum

Let p 3 be a prime number, F be a number field with _p F^x,and K = F(_p). In a previous paper, the author proved, undersome assumption on p and F, that an unramified cyclic extensionN/F of degree p has a normal integral basis if and only if thepushed-up extension NK/K has a normal integral basis. This addendumshows that the assertion holds without the above-mentioned assumption.