阿片类药物成瘾者瞳孔光反射的检测和特征提取

建立了一种基于图像处理的快速瞳孔直径检测算法,运用此算法提取了反映阿片类药物成瘾人员与正常人对瞳孔光反射变化差异的3个特征值:绝对收缩幅度(absolute amplitude of contraction,AAC)、相对收缩幅度(relative amplitude of contraction,RAC)和收缩斜率(SCV,slope of contraction velocity);分别研究了成瘾、性别、近视、年龄、睡眠剥夺等因素对于这3个特征值的影响。不同性别、近视人员、睡眠剥夺人员与正常人之间的3个特征值均无显著差异,成瘾人员与之对比均显著减小。老年人相对于正常青年人,3个特征值都明显减小;与成瘾人员相比,仅在RAC值上有显著差异。结果表明,阿片类药物成瘾人员除了与正常人外,也与其他具有潜在影响瞳孔变化因素的非阿片成瘾人员在瞳孔对光反射的特征值上具有显著差异。该研究的实验数据为进一步建立基于检测瞳孔对光反射其直径发生变化的方法来快速、非接触地鉴别出阿片类药物成瘾人员提供了可靠的依据。

1. 快速扫视系统对瞳孔对光反射系统的调制作用2. 麻醉状态下纳洛酮对吗啡依赖大鼠的岛叶神经元的自发放的影响

一. 快速扫视系统对瞳孔对光反射系统的调制作用快速扫视系统是研究运动神经控制的一个很好的模型。瞳孔对光反射是由进入视网膜的光亮度的增加而引起的瞳孔的收缩。之前的实验研究表明这两个系统都是开放的系统。但是对快速扫视系统是否对瞳孔对光反射系统有调制作用并没有研究过。本实验研究了注视状态和快速扫视状态下的瞳孔对光反射的潜伏期和瞳孔直径的变化。结果显示在注视状态下的和出现快速扫视时瞳孔对光反射的潜伏期表现出显著不同。外展和内收会引起瞳孔对光反射的潜伏期和瞳孔相对收缩率不同变化。在出现外展运动时，瞳孔对光反射的潜伏期显著下降，而出现内收运动时，瞳孔对光反射的潜伏期表现出显著增加。而瞳孔相对收缩率在出现两种运动时与注视状态下相比也发生不同的变化：外展运动引起瞳孔对光反射的瞳孔相对收缩率的增加，而内收运动引起瞳孔相对收缩率的减少。尽管快速扫视本身会引起瞳孔的收缩，但是引起的瞳孔收缩的变化不等于在出现快速扫视时的瞳孔对光反射的瞳孔直径的变化，这个结果说明在出现快速扫视时的瞳孔对光反射的变化并不是来源于光效应和快速扫视效应的简单叠加。基于快速扫视出现时间的进一步分析说明在瞳孔对光反射周期内不同时间出现两种快速扫视引起的瞳孔对光反射的潜伏期和瞳孔相对收缩率的变化不同。这些结果说明两个系统是有相互作用的，快速扫视系统可以调节瞳孔对光反射系统。关键词：快速扫视 瞳孔对光反射 调制二. 麻醉状态下纳洛酮对吗啡依赖大鼠的岛叶神经元的自发放的影响药物成瘾是药物长期作用于脑而产生的一种慢性复吸性脑疾病。之前有研究表明岛叶参与成瘾的过程。本实验以CPP为检测手段，检测实验大鼠是否产生吗啡依赖(吗啡给药方式为隔天给药，腹腔注射(10mg/kg)，共三次。然后采用四合一电极对纳洛酮诱发戒断的麻醉大鼠的岛叶和体感皮层进行细胞外电生理记录。与对照组相比，在记录的神经元中，被激活的神经元的所占比例（71.43%）远远大于对照组。将对照组和实验组的发放显著增加的神经元在给药前后的相对平均发放进行比较，两组神经元发放增加并没有显著差异。采用卡方检验比较了对照组和实验组的发放模式，结果显示两组发放模式存在显著差异。说明岛叶参与的方式可能是有更多数目的神经元参与，而不是通过改变单个神经元的发放参与。这也在神经元水平上为岛叶参与成瘾过程提供了一个证据。

A Nanomechanical Device Based on Light-Driven Proton Pumps

In this paper, a hybrid device based on a microcantilever interfaced with bacteriorhodopsin (bR) is constructed. The microcantilever, on which the highly oriented bR film is self-assembled, undergoes controllable and reversible bending when the light-driven proton pump protein, bR, on the microcantilever surface is activated by visible light. Several control experiments are carried out to preclude the influence of heat and photothermal effects. It is shown that the nanomechanical motion is induced by the resulting gradient of protons, which are transported from the KCl solution on the cytoplasmic side of the bR film towards the extracellular side of the bR film. Along with a simple physical interpretation, the microfabricated cantilever interfaced with the organized molecular film of bR can simulate the natural machinery in converting solar energy to mechanical energy.

Evaluation of influence of multiple scattering effect in light-scattering-based applications

The extinction cross sections of a system containing two particles are calculated by the T-matrix method, and the results are compared with those of two single particles with single-scattering approximation. The necessity of the correction of the refractive indices of water and polystyrene for different incident wavelengths is particularly addressed in the calculation. By this means, the volume fractions allowed for certain accuracy requirements of single-scattering approximation in the light scattering experiment can be evaluated. The volume fractions calculated with corrected refractive indices are compared with those obtained with fixed refractive indices which have been rather commonly used, showing that fixed refractive indices may cause significant error in evaluating multiple scattering effect. The results also give a simple criterion for selecting the incident wavelength and particle size to avoid the 'blind zone' in the turbidity measurement, where the turbidity change is insensitive to aggregation of two particles.

A characteristics study on the performance of a 2-stage light gas gun

In order to obtain an overall and systematic understanding of the performance of a two-stage light gas gun (TLGG), a numerical code to simulate the process occurring in a gun shot is advanced based on the quasi-one-dimensional unsteady equations of motion with the real gas effect,;friction and heat transfer taken into account in a characteristic formulation for both driver and propellant gas. Comparisons of projectile velocities and projectile pressures along the barrel with experimental results from JET (Joint European Tons) and with computational data got by the Lagrangian method indicate that this code can provide results with good accuracy over a wide range of gun geometry and loading conditions.

Beam splitter entangler for light fields

We propose an experimentally feasible scheme to generate various types of entangled states of light fields by using beam splitters and single-photon detectors. Two beams of light fields are incident on two beam splitters respectively with each beam being asymmetrically split into two parts in which one part is supposed to be so weak that it contains at most one photon. We let the two weak output modes interfere at a third beam splitter. A conditional joint measurement on both weak output modes may result in an entanglement between the other two output modes. The conditions for the maximal entanglement are discussed based on the concurrence. Several specific examples are also examined.

Reflection and refraction of light at the interface of a uniaxial bicrystal

This paper deals with a theoretical analysis of the reflection and refraction of light at the interface of a bicrystal by use of Maxwell's equations. For a general case, the formulas of Snell's Law and the four Fresnel coefficients for the reflection and refraction of extraordinary light at the interface of a uniaxial bicrystal are derived for the first time, as well as the Brewster angle value. The condition for total reflection is presented and the electromagnetic fields distributions at both sides of a bicrystal are presented when total reflection occurs.

Group velocity of probe light pulse in an open lambda system

The group velocity of the probe light pulse (GVPLP) propagating through an open Lambda-type atomic system with a spontaneously generated coherence is investigated when the weak probe and strong driving light fields have different frequencies. It is found that adjusting the detuning or Rabi frequency of the probe light field can realize switching of the GVPLP from subluminal to superluminal. Changing the relative phase between the probe and driving light. elds or atomic exit and injection rates can lead to GVPLP varying in a wider range, but cannot induce transformation of the property of the GVPLP. The absolute value of the GVPLP always increases with Rabi frequency of the driving light field increasing. For subluminal and superluminal propagation, the system always exhibits the probe absorption, and GVPLP is mainly determined by the slope of the steep dispersion.

Incoherent subharmonic light scattering in isotropic media

Incoherent subharmonic light scattering in isotropic media is a new kind of nonlinear light scattering, which involves single input photon and multiple output photons of equal frequency. We investigate theoretically the dependence of the subharmonic scattering intensity on the hyperpolarizability of molecules and the incident intensity using nonlinear optics theory similar to that used for Hyper-Rayleigh scattering and degenerate optical parametric oscillators. It is derived that the subharmonic scattering intensities grow exponentially or superexponentially with the hyperpolarizability of molecules and the incident intensity. (C) 2004 Elsevier B.V. All rights reserved.

Controllable group velocity of the probe light in a Lambda-type system with two fold levels

The group velocities of the probe laser field are studied in a A-type system where one lower state has two fold levels coupled by a control field. It is found that the interaction of double dark states leads to controllable group velocity of the probe field in this system. It can be easily realized, due to the interacting double dark resonances, that one of the group velocities at transparency positions is much slower than the other by tuning the control field to be off resonance. In particular, when the control field is on resonance. we can obtain two equal slow group velocities with a broader EIT width, which provides potential applications in quantum storage and retrieval of light. (c) 2005 Elsevier B.V. All rights reserved.

Bi-doped BaF2 crystal for broadband near-infrared light source

Bi-doped BaF2 crystal was grown by the temperature gradient technique and its spectral properties were investigated. The absorption, emission and excitation spectra were measured at room temperature. Two broadband emissions centered at 1070 and 1500 nm were observed in Bi-doped BaF2 crystal. This extraordinary luminescence should be ascribed to Bi-related centers at distinct sites. We suggest Bi2+ or Bi+ centers adjacent to F vacancy defects are the origins of the observed NIR emissions. (C) 2009 Optical Society of America

Polarization-dependent supercontinuum generation from light filaments in air

We investigate polarization-dependent properties of the supercontinuum emission generated from filaments produced by intense femtosecond laser pulses propagating through air over a long distance. The conversion efficiency from the 800-nm fundamental to white light is observed to be higher for circular polarization than for linear polarization when the laser intensity exceeds the threshold of the breakdown of air. (C) 2005 Optical Society of America.

Group velocity of the light pulse in an open V-type system

We investigate the group velocity of the probe light pulse in an open V-type system with spontaneously generated coherence. We find that, not only varying the relative phase between the probe and driving pulses can but varying the atomic exit rate or incoherent pumping rate also can manipulate dramatically the group velocity, even make the pulse propagation switching from subluminal to superluminal; the subliminal propagation can be companied with gain or absorption, but the superluminal propagation is always companied with absorption. (c) 2006 Elsevier GmbH. All rights reserved.