Physical Modeling of Low-Intensity IR Radiation Influence on Biological Tissues

Russian Journal of General Chemistry - The influence of pulsed and continuous low-intensity infrared radiation on the morphology of HEK-293 cell cultures is compared. The effect of pulsed IR...     

新鲜乳腺癌组织的近红外拉曼光谱分析

采用便携式拉曼光谱仪对正常、良性和恶性的乳腺癌组织进行检测,通过对其拉曼光谱的指认,归纳了其主要区别和特征. 在3类乳腺组织中有明显的脂类的特征峰（1230,1268,1301,1440和1743 cm^-1）,而在良性和恶性的组织中,则出现了较为明显的蛋白（1246,1271,1315和1364 cm^-1）和核酸（1340 cm^-1）的特征峰. 良性和恶性组织的区别在于恶性组织特有的特征峰（1340 cm^-1）,而良性组织所特有的特征峰则应归属为蛋白. 在数据分析过程中,选择能够反映样本化学本质的特征峰,利用高斯过程的机器学习对特征峰值建立模型. 特异性（0.94）、灵敏度（0.95）和Matthews相关系数（0.86）表明在模型中3种组织有比较良好的辨别度,对于应用拉曼光谱方法辨别正常和患病乳腺组织具有参考价值.     

Characterisation of Nanohybrids of Porphyrins with Metallic and Semiconducting Carbon Nanotubes by EPR and Optical Spectroscopy

Single‐walled carbon nanotubes (SWCNTs) are noncovalently functionalised with octaethylporphyrins (OEPs) and the resulting nanohybrids are isolated from the free OEPs. Electron paramagnetic resonance (EPR) spectroscopy of cobalt(II)OEP, adsorbed on the nanotube walls by π–π‐stacking, demonstrates that the CNTs act as electron acceptors. EPR is shown to be very effective in resolving the different interactions for metallic and semiconducting tubes. Moreover, molecular oxygen is shown to bind selectively to nanohybrids with semiconducting tubes. Water solubilisation of the porphyrin/CNT nanohybrids using bile salts, after applying a thorough washing procedure, yields solutions in which at least 99 % of the porphyrins are interacting with the CNTs. Due to this purification, we observe, for the first time, the isolated absorption spectrum of the interacting porphyrins, which is strongly red‐shifted compared to the free porphyrin absorption. In addition a quasi‐complete quenching of the porphyrin fluorescence is also observed.     

The Effect of Unpolarized Laser Radiation on Organic Dielectrics

Unpolarized radiation from the active species of a copper vapor laser changed the conductivity, dielectric permittivity, and the loss tangent of 14 organic dielectrics (polymers) including PMMA and polyethylene- and poly(vinyl chloride)-based materials. Light pulses of 20 ns duration, mostly at a wavelength of 510.6 nm, illuminated an entire sample by a large spot for 3–5 s, so that the radiation intensity per pulse at the surface was as high as 1.7–8.6 kW/cm². After irradiation, the conductivity of all materials increased. The electric parameters irreversibly varied in some dielectrics, whereas slow (of many hours) relaxation back to the initial parameters or to new equilibrium values was observed in other materials.     

基于稳健统计的新鲜乳腺组织拉曼光谱分析

采用便携式拉曼光谱仪对新鲜乳腺正常组织、良性组织和恶性组织进行检测,通过稳健统计方法对拉曼光谱数据进行分析处理,建立乳腺组织拉曼光谱标准图谱,根据标准图谱特征峰归纳3类组织的主要区别和特征.在3类乳腺组织中,正常组织有明显的脂类特征峰(1078,1297,1437,1653,1746 cm-1),而在良性和恶性组织中则出现了较明显的蛋白特征峰(1259,1530,1650 cm-1),正常、良性和恶性组织的主要区别集中在1340和1534 cm-1处,应归属为蛋白和类胡萝卜素,这一结果并不能由经典统计方法得出.基于稳健统计建立的新鲜乳腺组织拉曼光谱标准图谱为构建数学模型来鉴别乳腺病灶的性质奠定了基础.     

Optical absorption and EPR studies on tenorite mineral

Optical absorption and EPR studies of the mineral tenorite, a cupric oxide which originated from Mexico and contains 54.40 wt% of CuO. EPR spectral results indicate two Cu(II) closely interacting ions to give a d² type structure. The calculated spin Hamiltonian at room temperature and liquid nitrogen temperature is g = 2.160 and D = 125 G. The intensity of resonance line is not the same in low and high field regions. The optical absorption spectrum is due to Cu(II) in which three sets of energies indicating Cu(II) in two independent tetragonal C_4v symmetry, in addition to d² structure of octahedral coordination. The octahedral and tetragonal field parameters are compared with those reported for several other copper containing minerals.     

Optical absorption and EPR studies on beaverite mineral

The behaviour of transition metal ions in beaverite mineral has been studied by spectroscopic techniques such as electron paramagnetic resonance and absorption spectroscopy in the UV-vis and NIR regions. The ground state of Cu(II) ion in beaverite is confirmed as (2)B(1g) since g(parallel)>g(perpendicular) (2.42>2.097). A resonance noticed at g=2.017 is ascribed to Fe(III) impurity. Two sets of three characteristic bands observed in the optical absorption spectra are assigned to the same transitions, (2)B(1g)-->(2)A(1g), (2)B(1g)-->(2)B(2) and (2)B(1g)-->(2)E(g) of Cu(II) ion in tetragonal field. The presence of Fe(III) bands is supportive evidence for iron impurity in the mineral. Mid infrared spectrum is due to overtones and combination tones of water and hydroxyl groups.     

Effect of Laser-Induced Optical Breakdown on the Structure of Bsa Molecules in Aqueous Solutions: An Optical Study

The influence of laser radiation of a typical surgical laser on the physicochemical properties of the Bovine Serum Albumin (BSA) protein was studied. It was established that the physicochemical characteristics of optical breakdown weakly depend on the concentration of protein molecules. At the same time, the patterns observed for an aqueous solution of BSA irradiated with a laser for different time periods were extremely similar to the classical ones. It was established that after exposure to laser radiation, the optical density of protein solutions increases. At the same time, the intensity of BSA fluorescence due to aromatic amino acid residues decreases insignificantly after exposure to laser radiation. In this case, the position of the excitation and emission maximum does not change, and the shape of the fluorescence spot on 3D maps also does not change significantly. On the Raman spectrum after exposure to laser radiation, a significant decrease in 1570 cm⁻¹ was observed, which indicates the degradation of α-helices and, as a result, partial denaturation of BSA molecules. Partial denaturation did not significantly change the total area of protein molecules, since the refractive index of solutions did not change significantly. However, in BSA solutions, after exposure to laser radiation, the viscosity increased, and the pseudoplasticity of aqueous solutions decreased. In this case, there was no massive damage to the polypeptide chain; on the contrary, when exposed to optical breakdown, intense aggregation was observed, while aggregates with a size of 400 nm or more appeared in the solution. Thus, under the action of optical breakdown induced by laser radiation in a BSA solution, the processes of partial denaturation and aggregation prevail, aromatic amino acid residues are damaged to a lesser extent, and fragmentation of protein molecules is not observed.     

Effect of Laser Radiation on InSe and GaSe Thin Films Grown via Laser Sublimation and Chemical Deposition

Russian Journal of Physical Chemistry A - The formation of indium and gallium monoselenide thin films under the action of a powerful Nd : YAG laser is described. The use of laser...     

Optical absorption and EPR spectra of fuchsite

Chromium containing mica is called fuchsite. Fuchsite originating from the Nellore district of India containing 3.37 wt.% of chromium is used in the present study. Optical absorption and EPR studies were carried out at room temperature (RT). The optical absorption spectrum gives energies at 14925, 15070, 15715, 16400, 17730 and 21740 cm(-1), which are attributed to spin-allowed transitions for Cr(3+) in an octahedral symmetry. EPR spectra show a strong resonance with g=1.98 along with two sets of weak resonances which are attributed to two sets of chromium in the sample. The zero field splitting parameter (D) is almost zero. These spectra are due to Cr(3+) in the mineral. The NIR spectrum is due to hydroxyl ions in the sample.     

Effect of Radiation Defects on the Electronic Structure of Zircon by X-Ray Photoelectron Spectroscopy Data

X-Ray photoelectron spectroscopy (XPS) is used to study the electronic structure of radiation damaged samples of ZrSiO₄ zircon mineral at early and middle stages of its radiation destruction. The effects of radiation induced atomic disordering are found to be most distinctly manifested in the spectra of O1s states and to a smaller extent in the spectra of Si2p states, and also in the zircon valence band. Based on the quantum chemical calculation results the conclusion is drawn that the observed changes in XPS lines are caused by the formation of oxygen vacancy defects and an increase in the covalency of interatomic bonds near oxygen vacancies. For zircon samples with a low/moderate degree of radiation damage these changes reflect the initial stage of the polymerization of the ZrSiO₄ structure due to the formation of Si—O—Si chain fragments.     

Radiation effects in plutonium and carbonate co-doped calcium hydroxy apatite: An EPR study

Electron paramagnetic resonance studies were conducted on synthetic calcium hydroxy apatite samples co-doped with ²³⁹Pu and carbonate ion. These investigations were carried out to assess the self-irradiation effects in bone and teeth on exposure to plutonium, as calcium hydroxy apatite is the major constituent of bone and teeth. On self-irradiation, in addition to the signal from O^- ion arising from the radiolysis of hydroxide ion, EPR signals due to CO₂ ^-, PO₂ ^2- and another signal assigned to surface O^- ions were observed in the samples. In freshly quenched gamma irradiated samples, signals from CO₃ ^-, O^- , PO₂ ^2- and O₂ ^- ions were observed. The EPR signal of O₂ ^- ion shows a doublet splitting suggesting that O₂ ^- ion gets preferentially stabilized close to Pu⁴⁺. The radiation damage due to Pu⁴⁺ at Ca²⁺ sites, in the sample appears to be lower as compared to that due to external gamma-irradiation. Moreover, the alpha-dose in ²³⁹Pu doped samples has self-annealing effects. These are attributed to localized radiation damage due to alpha-particles compared to evenly distributed radical ions produced due to gamma-irradiation.     

Bacterial Cadmium Sulfide Semiconductor Particles: An Assessment of their Photoactivity by EPR Spectroscopy

Abstract— The bacterium Klebsiella aerogenes produces extracellular particles of cadmium sulfide in the presence of cadmium ions. The photoactivity of these particles has been studied using electron paramagnetic resonance (EPR) spectroscopy. Bacterial samples containing these semiconductor particles were irradiated with visible light in the presence of a spin trap, either phenyl-tert-butylnitrone (PBN) or 5,5-dimethyl-l-pyrroline-N-oxid(eD MPO). The results obtained reveal that a number of radicals, both oxygen and carbon based, are generated. Bacterial samples grown in the absence of cadmium ions exhibit weak, irradiation-independent EPR signals. These bacterially produced radicals are quenched when CdS particles are present. The observation of light-induced radicals provides evidence that the bacterial CdS particles are photoactive, behaving in a similar manner to inorganic CdS particles, and therefore could be used to mediate photocatalytic reactions.     

Overview of Popular Techniques of Raman Spectroscopy and Their Potential in the Study of Plant Tissues

Raman spectroscopy is one of the main analytical techniques used in optical metrology. It is a vibration, marker-free technique that provides insight into the structure and composition of tissues and cells at the molecular level. Raman spectroscopy is an outstanding material identification technique. It provides spatial information of vibrations from complex biological samples which renders it a very accurate tool for the analysis of highly complex plant tissues. Raman spectra can be used as a fingerprint tool for a very wide range of compounds. Raman spectroscopy enables all the polymers that build the cell walls of plants to be tracked simultaneously; it facilitates the analysis of both the molecular composition and the molecular structure of cell walls. Due to its high sensitivity to even minute structural changes, this method is used for comparative tests. The introduction of new and improved Raman techniques by scientists as well as the constant technological development of the apparatus has resulted in an increased importance of Raman spectroscopy in the discovery and defining of tissues and the processes taking place in them.     

Research of the Properties of Gadolinium Stearate by EPR Spectroscopy

Russian Journal of Coordination Chemistry - Gadolinium stearate is synthesized in the form of a micropowder. Its composition is determined by elemental and energy dispersive X-ray analyses:...     

同步辐射及相关核分析技术在纳米材料生物效应研究中的应用

伴随纳米技术的发展,纳米材料的生物效应研究成为热点,然而这一新兴的研究领域对传统的研究方法提出了挑战,其深入研究有赖于方法学的发展。同步辐射是具有高亮度、高准直、宽频谱等优异性质的光源,其在元素分析及物质原子或分子尺度的结构表征方面具有独特的优势。本文介绍了同步辐射及相关核分析技术,主要包括同步辐射X荧光分析、同步辐射X射线吸收光谱(扩展X射线吸收精细结构EXAFS,X射线吸收近边结构XANES)、同步辐射圆二色谱、电感耦合等离子体质谱、中子活化分析、同位素示踪技术等在纳米生物效应研究中的应用,结合本实验室以及国内外的研究工作详细阐述了基于同步辐射以及相关核分析方法应用于纳米材料表征及其在生物体内的定量、分布、结构分析等方面的最新进展。     

Optical absorption and EPR studies on some natural carbonate minerals

Limestone and dolomite minerals have been investigated by EPR and optical absorption studies. The optical absorption results indicate the presence of ferrous and ferric ion in both the minerals. The bands observed at 24,750, 22,780, 19,415 and 14,450cm(-1) are assigned to 6A1-->4T2 (4D), 6A1-->4E, 4A1 (4G), 6A1-->4T2 (4G) and 6A1-->4T1 (4G) d-d transitions of Fe3+ ions, respectively. A low energy band at 10,638cm(-1) is identified as being due to Fe2+ ion and can be attributed to 5T2g-->5E(g) transition. The weak band in the region 30,000-40,000cm(-1) corresponds to Fe-O charge transfer. Crystal field and Racah parameters evaluated for the Fe2+ ion are Dq=990cm(-1), B=885cm(-1) and C=3860cm(-1) and that for Fe3+ ions are Dq=1040cm(-1), B=703cm(-1) and C=3150cm(-1). The room temperature 9 and 35GHz EPR spectra of the minerals exhibit a sextet hyperfine pattern characteristic of Mn2+. The EPR parameters obtained for Mn2+ in limestone are g=2.00399, A= -9.411mT, D= -8.19mT and these values confirm that the Mn2+ ion are located in the calcite impurity. For Mn2+ in dolomite are g=2.0004, A= -9.45mT for Mn2+ substituted in the Ca lattice site and g=2.00984, A= -9.37mT, D= -9.94mT for substitution at the Mg site. The EPR spectra of heat-treated limestone and dolomite samples at 950 degrees C show a signal corresponding to CO2(-) ion.