Bacteriochlorin <Emphasis Type="Italic">e</Emphasis><Subscript>6</Subscript> as a sensitizer for photodynamic therapy

A simple scheme of modification of the native pigment bacteriochlorophyll a, extracted from the biomass of phototropic bacteria, for the purpose of obtaining a water-soluble derivative — bacteriochlorin e ₆ — which is similar in molecular structure to the effective sensitizer chlorin e ₆ and, in addition, has an intense longwave absorption band in the near-infrared region of the spectrum where biological tissues weakly absorb light — has been developed. The ease of production of bacteriochlorin e ₆ in combination with its physicochemical and spectral properties allow it to be considered as a promising sensitizer for photodynamic therapy.Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 71, No. 6, pp. 745–748, November–December, 2004.This revised version was published online in April 2005 with a corrected cover date.     

Study of the Interaction of Hemoglobin with Ligands from Resonance Raman Spectra

By the method of resonance Raman spectroscopy the equilibrium between liganded (HbL) and deliganded (Hb) forms of human hemoglobin is studied in destabilization of the solvate protein shell by introducing a cosolvent in the solution. It is shown that the introduction of ethanol leads to a nearly fivefold decrease in the ligand affinity of hemoglobin detected from the increase in the intensity of the 1355 cm^–1 ₄ line. The conformation of the heme and of the hemic pocket remains constant on addition of ethanol to the solution. Owing to the short time spent on measurement, this method can be used for a rapid evaluation of the influence of various preparations on the ligand affinity of hemoglobin.     

Photophysical Properties and Photoreduction of 5,10,15,20-Tetrakis-(4-N-Methylpyridyl)Porphyrin in Formamide

The photophysical characteristics and photochemical conversions of 5,10,15,20-tetrakis-(4-N-methylpyridyl)porphyrin in a highly polar solvent, formamide, are investigated. It has been established that no photochemical reactions occur on excitation in the visible spectral region, while UV excitation ( = 347 nm) causes photoreduction of porphyrin molecules followed by the formation of protonated products. The solvent molecules serve as a reducing agent. Photoreduction occurs in both air-saturated and deoxygenated solutions, but the nature of the products formed is different: chlorin molecules are formed in the air-saturated solutions and the successive photoconversion porphyrinphlorinporphometheneporphyrinogene occurs in the deoxygenated solutions.     

NMR relaxation spectroscopy: Interference effects

The nuclear magnetic resonance relaxation process and the relaxation spectroscopy is considered in the presence of interference (cross terms) between different spin interactions in a weak-collision approximation. New interference effects are presented.     

Molecular thermometers based on phosphorescent porphin metal complexes

We study the temperature dependence of the radiative deactivation of triplet states of Pdand Pt-porphin molecules in n-alkane matrices in the temperature range 4.2–210 K. The nature of the thermally activated “hot” lines that are observed in phosphorescence spectra of Pdand Pt-porphin is discussed in detail. We show that, because of the degeneracy lifting of the triplet state T _{1, 2} in the crystal field of n-alkane matrices, lines of the transitions T1 → S ₀ and T ₂ → S ₀ are spectrally spaced and, in all cases, the T ₂ state is the first state that is activated with increasing temperature. We analyze the dependences of the T ₂-T ₁ splitting on the chelated metal ion and the type of the matrix. The possibility of measuring cryogenic temperatures with molecular thermometers that use the thermochromic properties of Pdand Pt-porphin in n-alkane matrices is discussed.     

RP-LC for Determination of Plastochromanol,Tocotrienols and Tocopherols in Plant Oils

An isocratic high performance liquid chromatographic method, with the application of C₁₈ and C₃₀ reverse-phase column and fluorescence detection, is described for the analysis of plastochromanol, tocotrienols and tocopherols in plant seed oils. The solvent systems have been optimized to obtain high resolution for all tocochromanols and relatively short analysis time. The use of reverse-phase columns for plastochromanol analysis, previously not reported, enables very sensitive and selective detection of plastochromanol which under the described separation conditions did not interfere with tocochromanols or any other compounds. The sample extraction method is fast, simple and highly efficient. The obtained results show that plastochromanol was present in most of the investigated seed oils. Its level was the highest in flax (17–30 mg/100 g oil), rape (8.5–9), camelina (4.3), peanut (1.95), corn (1.69) and grape (1.31) seed oils. Its level in the other investigated oils was below 1 mg/100 g oil, and only in sesame and coconut oils it was not detected. Tocotrienols were found in most of the oils but their content was usually very low (<<1 mg/100 g oil) with the exception of grape, milk thistle and corn oils where it reached >1 mg/100 g oil. Tocopherol content and isomer composition was within the earlier reported literature values for the investigated oils.

     

Application of asymptotic methods to the investigation of one-frequency nonlinear oscillations of cylindrical shells interacting with moving fluid

We demonstrate the applicability of the Bogolyubov-Mitropol’skii asymptotic method to the construction of one-frequency solutions of a system of nonlinear equations used to describe the multimode free, forced, and parametrically excited vibrations of cylindrical shells interacting with moving fluid. __________ Translated from Ukrains’kyi Matematychnyi Zhurnal, Vol. 59, No. 4, pp. 476–487, April, 2007.     

Fluorescent properties and symmetry of the monodeprotonated form of 5,10,15,20-tetrakis-(4-N-methylpyridyl)-porphyrin

The spectral and kinetic properties of the monodeprotonated form of the cationic 5,10,15,20-tetrakis(4-Nmethylpyridyl) porphyrin (H₂TMPyP) in solution are studied. The experimental results obtained are interpreted based on the four-orbital Gouterman model. It is established that the monodeprotonated form HTMPyP⁻ can be assigned to the D4h symmetry point group, and has spectral and photophysical characteristics similar to the characteristics of the fluorescent metal complexes of H₂TMPyP with relatively low electronegativity of the chelated metal ion. It is hypothesized that formation of the monodeprotonated form HTMPyP⁻ is accompanied by a decrease in the oxidation potential of the porphyrin molecule. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 5, pp. 613–619, September–October, 2006.     

On the spectrum of natural frequencies of circular cylindrical shells completely filled with a fluid

The natural frequencies of cylindrical shells filled with a fluid and having the ends either simply supported or clamped are determined. Conditions are studied under which the natural frequencies of the shell are close or multiple __________ Translated from Prikladnaya Mekhanika, Vol. 42, No. 5, pp. 42–49, May 2006.     

Tuning of the Temperature Window for Unit‐Cell and Pore‐Size Enlargement in Face‐Centered‐Cubic Large‐Mesopore Silicas Templated by Swollen Block Copolymer Micelles

The unit‐cell size and pore diameter as functions of temperature are investigated in the syntheses of FDU‐12 silicas with face‐centered cubic structure templated by Pluronic (PEO‐PPO‐PEO) block copolymer micelles swollen by toluene. The temperature range in which the unit‐cell size and pore size strongly increase as temperature decreases is correlated with the critical micelle temperature (CMT) of the surfactant. While Pluronic F127 affords a wide range of unit‐cell parameters (28–51 nm) and pore diameters (16–32 nm), it renders moderately enlarged pore sizes at 25 °C. The use of Pluronic F108 with higher CMT affords FDU‐12 with very large unit‐cell size (～49 nm) and large pore diameter (27 nm) at 23 °C. Large unit‐cell size (40–41 nm) and pore size (22 nm) were obtained even at 25 °C. The application of Pluronics F87 and F88 with much smaller molecular weights and higher CMTs also allows one to synthesize FDU‐12 with quite large unit‐cell parameters and pore sizes at room temperature. The present work demonstrates that one can judiciously select Pluronic surfactants with appropriate CMT to shift the temperature range in which the pore diameter is readily tunable.