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.     

The effect of evanescent wave modes on scattering and near-trapping

The effect of evanescent modes on the scattering and near-trappingof small-amplitude waves over axisymmetric topography is investigated.A two-stage numerical implementation, which facilitates an examinationof the resonant frequencies associated with near-trapping, isdeveloped. This is achieved in the latter stage of the procedureby dealing with the progressing and decaying waves separately. Numerical results are given for a selection of bed shapes, andit is found that the evanescent waves can have a significanteffect on scattering. Numerical evidence is found that, forthe selection of bed profiles considered, no new resonant frequenciesare introduced by the inclusion of the decaying wave components,but that the inclusion of these decaying waves does improveprevious approximations to resonant frequencies.     

双折射光纤受激喇曼散射的研究

本文详细地研究了双折射光纤的受激喇曼散射.观测到9级斯托克斯受激喇曼谱.文中讨论和测试了阈值和频移与泵浦光偏振方向间的关系;当泵浦光偏振方向与光纤椭圆核的长轴或短轴平行时的传输损耗.并根据测得的阈值在理论上计算了各级斯托克斯线的喇曼增益系数.     

Small-angle scattering of polarized light. IV. Isotropic to birefringent transition for spheres

The Rayleigh-Gans-Debye approximation is used to investigate the small-angle, cross-polarized light scattering by a sphere of radius a, birefringence Δμ and relative index μ. If θ_max is the polar scattering angle of the intensity maxima, the quantity Û_max = 4πa/λ × sin (θ_max/2) behaves in two different ways according to the signs of Δμ and μ ? 1. When Δμ > 0, μ > 1 or Δμ < 0, μ < 1, then Û_max varies from 2.8 to 4.1 as Δμ increases from zero. If Δμ < 0, μ > 1 or Δμ > 0, μ < 1, then Û_max goes from 2.8 to about 6, thereafter decreasing to 4.1. Another interesting result is that the value of Û_max for a highly briefringent sphere is 4.1 only for large diameters. It decreases to 4.0 when the diameter decreases.     

The kink of cellular automaton rule 18 performs a random walk

We give an exact characterization of the movement of a single kink in the elementary cellular automaton Rule 18. It is a random walk with independent increments as well as independent delay times. Its statistical parameters are computed to confirm the earlier simulation results by Grassberger.     

Method of Self-Mixing in the Spectroscopy of Quasielastically Scattered Laser Radiation

Interaction of a semiconductor laser with its self-radiation quasielastically scattered in the environment is considered. It is established that at small coefficients of coupling of the laser with the scattering medium the spectral density of the power of an optoelectronic signal in the laser faithfully reproduces the shape of the scattered-radiation spectrum at the Doppler-shift frequencies. This makes it possible to measure the spectrum with a resolution characteristic for optical homodynation by recording the optoelectronic signal.     

Neutron Scattering on Magnetic Materials Under Extreme Conditions

Many materials exhibit various magnetic phenomena as a function of magnetic field, temperature and/or pressure. Usually, bulk magnetic measurements provide first information on the magnetic state of the material by measuring their response on the applied magnetic field. However, it is necessary to investigate materials also on a microscopic scale. This is often done by means of neutron scattering. In this contribution we discuss basic ideas of this method and we report on few experimental results obtained with a split-pair coil 14.5 T superconducting magnet which can be combined with dilution stick offering temperatures as low as 30 mK and/or with a small clamped-type pressure cell which offers pressure up to 1.0 GPa.     

LDS751染料的受激喇曼散射

报道了用532nm激光抽运LDS751染料产生720—780nm可调谐染料激光输出的同时,观察到喇曼频移为102和45cm-1的反斯托克斯线,前者谱线较强,后者较弱.与这两条强线对应的斯托克斯线未能观察到.另外,还观察到喇曼频移为34cm-1的一级和二级斯托克斯线与反斯托克斯线 关键词： LDS751染料 受激喇曼散射 喇曼位移 斯托克斯线 反斯托克斯线     

Light scattering by groups of spherical particles

Light scattering by groups of spherical particles is considered. It is shown that the structure of the groups and their orientational distribution can be judged from the spectrum and polarization of the scattered light. Syktyvkar State University, 55, Oktyabr'skii Ave., Syktyvkar, 167001, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 2, pp. 228–231, March–April, 1997.