Light Scattering Changes in Isolated Brain Mitochondria during Anoxia - Magnesium Effect on Morphological Changes and Respiration -

Under pathological conditions, morphological changes of the cells and tissues may differ from those of normal conditions, which can be reflected by changes in light scattering (LS). Consequently, LS has been recognized as a potential non-invasive tool for optical diagnosis of living tissue. This paper aimed to identify the basic properties of LS of isolated brain mitochondria in vitro under normoxic and anoxic conditions in the presence and absence of Mg²⁺. An increase in LS was observed during anoxia in both the presence and absence of Mg²⁺. In both cases, the changes in LS initiated by anoxia and reoxygenation started concomitantly with the reduction of heme aa₃. The rates of LS changes were slower than those of heme aa₃, particularly in the presence of Mg²⁺. Mg²⁺ inhibited the morphological responses of mitochondria caused by the addition of ADP and ATP, and significantly reduced the oxygen consumption rate in state 4. These results are due to modulation of the K⁺/H⁺ antiporter affected by Mg²⁺. In addition, the mitochondria were well coupled, although the basal level of LS fell after addition of Mg²⁺. Therefore, the observed responses of mitochondria at anoxia were physiological and independent of the presence or absence of Mg²⁺. The relationship between LS and redox state of cytochrome c oxidase, an anoxic indicator, provides a basis to assess the tissue conditions in vivo.     

Fatigue gage utilizing slip-initiation phenomenon in electroplated copper foil

Fundamental experiments are carried out to examine the parameter that dominates the slip-band initiation in electroplated copper foil under the condition where the mean stress as well as the stress amplitude varies. In the case of constant-amplitude stressing, the relation between the critical stress for the slip-band initiation σ _p and the number of cyclesN is well represented by σ _p ^α N=C. In other words, the slip bands appear when the total hysteresis energy applied to the copper foil attains a critical value. In the case of variable stresses, the range-pair mainly dominates the occurrence of the slip bands, and Miner's linear cumulative damage rule holds for the accumulation of the fatigue damage for the slip-band initiation. Accordingly, the parameter (Σσ _i ^α n _i/Σn _i)^1/α is equivalent to the critical stress σ _p under constant amplitude stressing, where σ _i andn _i are the stress amplitude and the number of cycles counted by the range-pair method, respectively, and α is the exponent of the σ _p -N relation. Based on these results, the applicability of the copper foil to the fatigue gage that accumulates and indicates a load experience is discussed.     

On energy estimates for second order hyperbolic equations with Levi conditions for higher order regularity

We consider energy estimates for second order homogeneous hyperbolic equations with time dependent coefficients. The property of energy conservation, which holds in the case of constant coefficients, does not hold in general for variable coefficients; in fact, the energy can be unbounded as t → ∞ in this case. The conditions to the coefficients for the generalized energy conservation (GEC), which is an equivalence of the energy uniformly with respect to time, has been studied precisely for wave type equations, that is, only the propagation speed is variable. However, it is not true that the same conditions to the coefficients conclude (GEC) for general homogeneous hyperbolic equations. The main purpose of this paper is to give additional conditions to the coefficients which provide (GEC); they will be called as C ^k -type Levi conditions due to the essentially same meaning of usual Levi condition for the well-posedness of weakly hyperbolic equations.     

The Repulsion Between Localization Centers in the Anderson Model

In this note we show that, a simple combination of deep results in the theory of random Schrödinger operators yields a quantitative estimate of the fact that the localization centers become far apart, as corresponding energies are close together.     

Abietanes and a Novel 20‐Norabietanoid from Plectranthus cyaneus (Lamiaceae)

Antioxidative‐activity‐guided fractionation of extracts of the aerial parts of the title plant yielded the two novel abietanoid diterpenoids 11,20‐dihydroxysugiol (=11,12,20‐trihydroxyabieta‐8,11,13‐trien‐7‐one; 3 ) and 1,11‐epoxy‐6,12‐dihydroxy‐20‐norabieta‐1(10),5,8,11,13‐pentaen‐7‐one ( 4 ) in addition to 11‐hydroxysugiol (=12‐O‐demethylcryptojaponol=11,12‐dihydroxyabieta‐8,11,13‐trien‐7‐one; 2 ) and the main constituent carnosolon (=6,20‐epoxy‐6,11,12‐trihydroxyabieta‐8,11,13‐trien‐7‐one; 1 ). The structures were established on the basis of spectroscopic, chiroptic, and X‐ray crystallographic evidence.     

Chemistry of organosilicon compounds : LXXX. Useful modifications in the preparation of trimethylsilylsodium and trimethylsilylpotassium

New procedures for preparation of trimethylsilylsodium and trimethylsilylpotassium, which gave coupling products with primary and secondary alkyl chlorides in high yields, are reported.     

Far infrared absorption by acceptor states in tellurium

Transmission spectra of slightly antimony-doped tellurium were measured at 2K. Absorptions due to transitions of holes from the acceptor ground state to the excited state and to the valence band were observed. Reflecting the double-maximum structure of the valence band, the ground state splits into two levels, the binding energies of which are found to be 1.31 and 1.47 meV, respectively.     

A new tomato pregnane glycoside from the overripe fruits

A new pregnane glycoside has been isolated from the overripe fruits of Cherry tomato (Mini tomato), Lycopersicon esculentum var. cerasiforme (DUNAL) ALEF. The structure was determined to be 3-O-beta-lycotetraosyl 3beta-hydroxy-5alpha-pregn-16-en-20-one on the basis of spectroscopic analysis. The seasonal variation of the tomato saponin is discussed.     

A light-scattering study of deformation of liquid-crystalline spherulites of poly(γ-benzyl-L-glutamate) in an electric field

The deformation of liquid-crystalline spherulites of poly(γ-benzyl-L -glutamate) (PBLG) in an electric field was investigated by light scattering, polarized-light microscopy, and birefringence measurements. Under the polarizing microscope, the deformation was found to be dependent upon the field strength. The spherulites deformed perpendicular to the field. Above 75 V/cm in N,N-dimethylformamide or 120 V/cm in 1,1,2-trichloroethane, the deformed spherulites were transformed to rodlike textures. With increasing voltage, the rods gradually oriented parallel to the electric field. On the basis of the experimental results, models for affine deformation are proposed. With these models, light-scattering patterns are calculated. The calculated and experimental patterns agree semiquantitatively.     

Band engineering of silicon for light emission: First-principles approach to the effect of co-doping with nitrogen and fluorine

A Si-based light emitter has long been the final key component for electronic and photonic integrated circuits on Si, because Si has an indirect band gap. Atomistic and electronic structures and energy gains of formation of possible nitrogen (N) and fluorine (F) complexes in Si have been researched from first-principles, in order to engineer the band structure of Si for light emission. The calculated results show that the substitutional nitrogen N_S and bond center fluorine F_BC pair complex has large stabilization energy, and that the pair-complex-doped Si has direct band gap, which is reduced with respect to that of Si. These results lead to the possibilities of doping-based engineering of Si optical properties with introduction of deep-level impurity and charge compensation.