Spectral luminescence properties of indotricarbocyanine dye in biological tissues

We have established that the shape and position of the maximum in the fluorescence spectrum of an indotricarbocyanine dye in tumor and normal tissues in vivo change over time after intravenous injection of the dye. Based on analysis of the spectral properties of the dye in vivo and in blood plasma, the dependence of the properties on the time since injection has shown that in the living body, the environment of the dye molecule changes as the photosensitizer goes from the skin into the tissue. We have established that in tissues in vivo, the dye molecules are localized in a region with low dielectric constant of the medium. We have shown that the change in the ratio of the concentrations of the different forms of hemoglobin in the blood has an effect on the absorption and shape of the fluorescence spectrum of the dye in tissues in vivo.     

Spectral Properties of Single BODIPY Dyes in Polystyrene Microspheres and in Solutions

The absorption, fluorescence, fluorescence quantum yield, and photostability of five BODIPY dyes are characterized and compared as single dyes in two environments, in 40-nm polystyrene spheres and in solution. The absorption and fluorescence spectra of the dyes in spheres are similar in profile but shifted to lower energies compared to those in solution. All the dyes are highly fluorescent, with three having fluorescence quantum yields of 1.0. For three of the five dyes, the yields were the same in spheres as in solution (1.00, 1.00, and 0.73). The high concentration of these dyes in spheres does not quench their fluorescence. For two other dyes the yields dropped, from 1.00 to 0.55 in one case and 0.83 to 0.50 in another, comparing the dyes in solution versus in spheres. The photodegradation of the dyes decreases in spheres compared to in solution in all but one case. For one dye, it decreases as much as 800-fold. Dyes overlooked because of low fluorescence or stability in solution could become useful fluorescent materials in the microsphere environment.     

夏秋两季洱海、太湖表层混合层的深度变化特征及其机理分析

湖泊表层混合层深度的变化不仅影响湖泊水生生态系统的演变, 而且影响流域的局地气候、降水量的时空格局等. 基于2008年夏秋两季洱海(高原湖泊)和太湖(平原湖泊)的气象与水温廓线观测资料, 分析探讨了两湖表层混合层深度的变化特征及其机制. 结果表明: 夏季洱海能维持持续的分层现象, 秋季有明显的日分层现象, 而在相应的两季中, 太湖仅可能存在日分层现象; 洱海表层混合层深度较同期太湖更浅; 太湖两季的表层混合层深度变化较洱海频繁, 即太湖水体混合与分层的交替过程对气象条件的响应较洱海更为迅速. 太湖这类浅水湖泊, 水深是抑制其存在稳定、持续分层的关键因素, 在合适的辐射条件下, 可形成日分层现象; 而洱海这类深度的湖泊, 净热量通量是影响其是否存在持续、稳定分层的主要因子. 该研究为进一步探讨湖泊与大气两种湍流运动的耦合机制及水生生态环境演替规律等提供了有力的参考.     

ICP-AES测定云南楚雄糖尿病患者发样微量元素的研究

探讨微量元素与糖尿病间的关联性及临床意义。采用ICP-AES等离子体发射光谱仪测定了楚雄地区糖尿病患者人发中11种元素,采用2,3-二氨基萘荧光法测定发样中的硒元素。选取糖尿病患者120例,对照组35例。糖尿病组发样中常量元素Ca、Mg低于对照组,P高于对照组;除Cd、Cr、Fe外,微量元素Zn、Se、Ni、Mn、Cu等5种元素低于对照组,并有显著差异(P0.01)。糖尿病组间性别比较数据显示男性除发Ni、Mn、P外,其余元素含量均低于女性,其中发锌远低于女性。3个不同年龄段糖尿病人群的微量元素含量变化显示Fe、P2种元素随年龄增加含量增高;Mg、Cd2种元素随年龄增加含量减少;其余各元素变化情况为Fe、P元素在老年组中较高,Cu、Cd、Mg较低;Mn、Cr、Cu元素含量在中年组中较高,而Zn、Se略低;Zn、Se在青年组较高,而Mn、Cr低。城市人群发中Zn、Cd、Cu、Mg、Ca含量比农村人群高;Se元素含量二者间差别也不大,其余元素含量均低于农村人群。楚雄地区糖尿病患者发中Zn、Se、Mg、Mn4种元素水平低,楚雄地区糖尿病患者致病原因可能与地区属低Se水平和患者体内硒水平低有关。     

An investigation of solid-solid phase transitions in cholesterol and in cholesteryl oleate by positron annihilation

The lifetimes of positrons annihilating in cholesterol and in cholesteryl oleate have been measured as a function of temperature in the vicinity of a previously reported solid-solid transition in each compound. The observed changes in lifetime parameters are discussed in terms of structural changes occurring in these two compounds.     

DC electric-field-induced heterophase structure on the surface of a peierls metal

A theoretical study has been made of the formation of a heterostructure of alternating metallic and semiconducting phases in atomic chains of a Peierls-metal surface monatomic layer placed in an electrostatic field normal to the surface. It is shown that an increase in the electric field results in an increase in the critical temperature of the metal-semiconductor phase transition on the sample surface, an increase in the temperature interval within which the heterostructure exists, a decrease in its spatial period, and an increase in the depth of spatial modulation of the gap in the electronic spectrum.     

动力学阿尔文波及其在太阳和空间等离子体中的应用

动力学阿尔文波是短波长的色散阿尔文波,其色散主要是由于垂直波长接近离子回旋半径或电子惯性长度等微观粒子动力学特征尺度而引起的。在频率远低于离子回旋频率的低频条件下,其平行波长通常仍然远大于离子惯性长度,这导致动力学阿尔文波在电磁偏振和传播方向上呈现显著各向异性的重要特性,并因此使其在磁等离子体的粒子能化现象和结构丝化现象中起重要作用。动力学阿尔文波早期于1970年代由Chen和Hasegawa研究聚变等离子体加热问题时首先提出。随后,在1980年代受到空间等离子体、特别是电离层-磁层耦合与极光现象研究的广泛关注。进入1990年代后,由于在空间卫星探测技术和地面等离子体实验技术的不断发展,特别是一些高分辨空间等离子体探测仪器和地面大型等离子体实验设备投入工作以来,在动力学阿尔文波的实验研究上取得了一系列突破性的重要进展。这不仅导致对动力学阿尔文波在磁等离子体动力学现象中重要作用的重新估价和正视,并再次激发了对动力学阿尔文波理论及其在实验室、空间和天体环境下各类等离子体活动现象中应用研究的广泛兴趣。自1990年代中期以来,我们在中国科学院紫金山天文台的研究小组一直致力于动力学阿尔文波及其在太阳和空间等离子体粒子能化现象中应用的研究。这篇综述性报告主要介绍了有关动力学阿尔文波非线性孤波理论及其在空间和太阳等离子体粒子能化现象中应用的研究进展,也是我们这十几年来在这一领域研究工作的一个总结。报告的第一章简要介绍动力学阿尔文波的一些主要特征及其在磁等离子体动力学现象中的重要作用。然后,在第二章中利用等离子体的双流体方程、结合有关的实验观测,系统介绍了动力学阿尔文波的色散、传播、偏振等基本特性和在一维孤波与二维涡旋等非线性结构理论方面的研究进展。接下来的第三、四、五章将聚焦在动力学阿尔文波的耗散机制及其在太阳和空间等离子体粒子能化现象中的应用研究上,分别包括：动力学阿尔文孤波的耗散结构及其在极光高能电子加速现象中的应用（第三章）;动力学阿尔文孤波中重离子的各向异性能化机制及其在延伸日冕中少量重离子反常加热现象中的应用（第四章）;以及动力学阿尔文波的反常耗散机制及其在日冕磁等离子体结构非均匀加热现象中的应用（第五章）。最后的第六章是一个简要的总结和几点进一步发展的展望。     

在NaCl和HTAB共存条件下甲基纤维素溶液凝胶化行为

利用流变仪研究了甲基纤维素(MC)溶液在NaCl、十六烷基三甲基溴化铵(HTAB)以及两者共存下MC溶液的凝胶化行为,发现其凝胶化温度随着NaCl浓度的增加而下降,随着HTAB浓度的增加而上升;但是MC/NaCl的凝胶化温度保持不变,与HTAB浓度 无关,而MC/HTAB溶液的凝胶化温度则随着NaCl浓度的增加而下降．以上的实验结果表明,在NaCl存在下,HTAB将被诱导形成胶束,因此MC/NaCl的凝胶化温度保持不变;反之,当NaCl不存在时,HTAB将优先吸附到MC上而不会在溶液中形成胶束,尽管其浓度     

On the Energy of a “Two-Dimensional” Two-Electron Atom

With the use of the known solution of the Schrödinger equation for an electron in the nucleus field in the polar coordinates, the energy of a “two-dimensional” two-electron atom in the ground state, as well as its single ionization energy, has been calculated both in perturbation theory and with an almost century-old method of variation of the parameter Z in a trial wavefunction of the ground state. Since such two-dimensional atoms, e.g., helium atoms, can in principle be implemented in experiments by “freezing” of one degree of freedom in the phase of Bose–Einstein condensate, the conclusions made in this work can be tested. Fundamental features of the calculation of the energy of “one-dimensional” two-electron atoms and the formation of their Bose–Einstein condensate have also been discussed. The results obtained in this work coincide in a number of particular cases with the results obtained in a previous work, where some results were absent.     

IR spectroscopic methods for diagnosis of oncological pathologies in human tissues (Review)

Modern problems in the diagnosis of oncological pathologies using spectroscopic methods of analysis are considered. Fourier-transform IR spectroscopy methods are illustrated by investigation of tissues of breast, thyroid gland, stomach, kidney, lung, and skin excised during surgical intervention. IR spectra of surgical material are compared with data of histological analysis. Spectra of proteins and lipids in malignant neoplasms differ from those in benign tumors and in tissues beyond the pathological focus. Differences in protein spectra are attributed to changes in the supramolecular structure due to cleavage of intramolecular C=OH–N hydrogen bonds. Differences in IR spectra of lipids in neoplasms, when compared with those in normal tissues, are caused by changes in the structure of side chains of fatty-acid radicals appearing in malignant tumors. Spectral signatures of malignant pathology are revealed.