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.     

Spectral-Luminescent Studies of the “Photolon” Photosensitizer in Model Media and in Blood of Oncological Patients

Using the methods of steady-state absorption and fluorescence spectroscopy and flash-photolysis, the new photosensitizer Photolon (Stock Company Belmedpreparaty) and its basic chromophore part — the substance chlorin e ₆ — have been studied under model conditions. It has been shown that there are no considerable differences between the spectral-luminescent characteristics of Photolon and chlorin e ₆ at a concentration not exceeding 2.5·10^–5 M in ethanol, phosphate-saline buffer (pH 8.5), and isotonic solution. That is, the polyvinyl-pyrrolidone (PVP) entering into the composition of Photolon does not influence the chromophore characteristics being investigated. It has been found that an increase in the mass fraction of PVP in the buffer solution of chlorin e ₆ leads to an increase in the degree of polarization of chlorin e ₆ fluorescence and to a change in the spectral-luminescent and kinetic characteristics, pointing to the fact that the pigment is built into the hydrophobic portions of the polymer. Using the method of multiple scattering of light, it has been shown that both Photolon and chlorin e ₆ are present in the whole blood of donors and oncological patients mainly in the monomeric form; Photolon is quickly removed from the blood of patients (after 24 h, C 10^–3 mg/ml).     

Raman spectra of tetrapyrrole photosensitizer chlorin <Emphasis Type="Italic">e</Emphasis><Subscript>6</Subscript> and their interpretation

The resonance and surface enhanced Raman scattering (SERS) spectra of chlorin e 6 trisodium salt in aqueous solutions, solid films, and adsorbed on the silver-coated surface of porous silicon are presented. Using the quantum-mechanical density functional method, the geometric structure and vibrational frequencies of the chlorin e ₆ molecule are calculated and the Raman spectrum of this molecule is interpreted for the first time. The geometry of sorption of chlorin e ₆ on the surface of a nanostructured silver film is considered based on a comparative analysis of the resonance Raman and SERS Raman spectra in the approximation of a short-range mechanism of Raman scattering enhancement.     

Formation of an Equilibrium Complex of Lactate Dehydrogenase with Chlorin e 6

Using spectrophotometric, spectral-luminescent, and polarization methods, we have detected the formation of strong equilibrium complexes of a key glycolytic enzyme — lactate dehydrogenase — with a promising photodynamic sensitizer — chlorin e ₆. It has been established that enzymes serve as the most sensitive targets destroying tumor cells subjected to photodynamic therapy.     

Influence of the sample orientation in Sn<Subscript>2</Subscript>P<Subscript>2</Subscript>S<Subscript>6</Subscript> crystals on the hydrostatic piezoelectric coefficients

The influence of the sample orientation on the effective value of the hydrostatic piezoelectric coefficients d _h ⁽ⁱ⁾ of Sn₂P₂S₆ crystals has been studied. The hydrostatic piezoelectric coefficients d _h ⁽¹⁾ and d′ _h ⁽³⁾ , were measured, d _h ⁽¹⁾ =(244±3) pC/N and d′ _h ⁽³⁾ =(92±1) pC/N. The hydrostatic piezoelectric coefficient d _h ⁽³⁾ for orthogonal axis system was calculated to be d _h ⁽³⁾ =(87±2) pC/N. The, optimal orientation of the sample has been found as (Xy l)−20°-cut. Maximal value of the effective hydrostatic piezoelectric coefficient d _h ⁽¹⁾ equals 260 pC/N. Double rotated samples were also studied. The orientation of the samples insensitive to the pressure has been found. The theoretical mean value of hydrostatic piezoelectric coefficient (d _h ) _mean corresponding to randomly oriented Sn₂P₂S₆ grains in a poled composite has been calculated to be (d _h ) _mean =136 pC/N.     

Mechanism of complexing of chlorin <Emphasis Type="Italic">e</Emphasis><Subscript>6</Subscript> and tetra(<Emphasis Type="Italic">p</Emphasis>-carboxyphenyl)porphyrin with malate dehydrogenase

The mechanism of complexing of the tetrapyrrole-nature photodynamic sensitizers chlorin e₆ and tetra(p-carboxyphenyl)porphyrin (TCPP) with the Krebs-cycle enzyme malate dehydrogenase (MDG) has been investigated by spectral-luminescence methods. It is shown that each subunit entering into the composition of the MDG dimer molecule forms an equilibrium complex with one dye molecule. However, if the sites of bonding of TCPP on a protein molecule are independent, the MDG-chlorin e₆ complex has a negative cooperativity since after the dye is incorporated into the first subunit of the macromolecule, its penetration to the second subunit becomes difficult. This is explained by the fact that conformation transformations, arising as a result of the incorporation of chlorin into one of the MDG subunits, are transferred to the site of its bonding on other MDG subunits through the intersubunit contacts of the enzyme. It has been established that photosensitizers compete with the hydrophobic fluorescent probe 8-aniline-1-naphthalenesulfonate (ANS) (whose position in the MDG macromolecule was described in detail in the literature) for the sites of bonding on the protein molecule, which allows the conclusion that TCPP and chlorin e₆ are localized in the catalytic domain of MDG. In this case, the sites of bonding of these dyes and the sites of bonding of nicotinamide-adenine dinucleotide, occupying the MDG domain that bonds coenzymes, do not interact with each other.__________Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 1, pp. 111–118, January–February, 2005.     

Regularities of Bonding of Chlorin e 6 to the Oligomeric Enzyme Lactate Dehydrogenase

Using differential-spectrophotometry, spectral-luminescence, and polarization methods, we have investigated regularities of complexing of a promising photodynamic sensitizer — chlorin e ₆ — with a key glycolytic enzyme — lactate dehydrogenase (LDH). The parameters of the dye–enzyme complex have been estimated by the difference between the spectral characteristics of the free dye and the dye bonded to the enzyme. It is shown that the tetrameric LDH molecule forms an equilibrium complex with four chlorin molecules and the sensitizer is bonded independently to each subunit entering into the composition of the tetramer. It has been established that the spectral characteristics of chlorin bonded to LDH are sensitive to the structure transformations arising in the active center of the enzyme as a result of the formation of an unproductive enzyme–coenzyme–substrate complex, which allows the conclusion that the dye is localized in the neighborhood of the active center of LDH.     

n/p-Type changeable semiconductor TiO<Subscript>2</Subscript> prepared from NTA

A novel kind of nano-sized TiO₂ (anatase) was obtained by high-temperature (400–700°C) dehydration of nanotube titanic acid (H₂Ti₂O₄(OH)₂, NTA). The high-temperature (400–700°C) dehydrated nanotube titanic acids (HD-NTAs) with a unique defect structure exhibited a p-type semiconductor behavior under visible-light irradiation ( nm, E _photon=2.95 eV), whereas exhibited an n-type semiconductor behavior irradiated with UV light ( nm, E _photon=3.40 eV).     

Dynamics and efficiency of the photosensitized singlet oxygen formation by chlorin <Emphasis Type="Italic">e</Emphasis><Subscript>6</Subscript>: The effects of the solution pH and polyvinylpyrrolidone

The effects of the solution pH and polyvinylpyrrolidone on the dynamics and efficiency of the formation of singlet oxygen ¹O₂ in buffer media (pH 6.3–8.5) photosensitized by chlorin e ₆ are studied. It is demonstrated that the quantum yield of the ¹O₂ formation photosensitized by chlorin e ₆ decreases with decreasing solution pH due to the aggregation of photosensitizer molecules. Polyvinylpyrrolidone facilitates the disaggregation of chlorin e ₆, thus increasing its photosensitizing ability. For a complex of chlorin e ₆ with this polymer, the luminescence kinetics of singlet oxygen is inverted, which should be taken into account in the determination of the lifetime of ¹O₂ in real biological systems.     

D<Subscript>s0</Subscript><Superscript>+</Superscript>(2317) as an iso-triplet four-quark meson

Although assigning D _s0 ⁺(2317) to the I ₃ = 0 component of iso-triplet four-quark mesons is favored by experiments, its neutral and doubly charged partners have not yet been observed. It is discussed why they were not observed in inclusive e ⁺ e ^-→cˉ experiment and that they can be observed in B decays.     

Dynamics of photosensitized singlet oxygen generation and photophysical characteristics of chlorin <Emphasis Type="Italic">e</Emphasis><Subscript>6</Subscript> in photolon ointment

We have used luminescence and absorption spectroscopy to study the dynamics of photosensitized singlet oxygen generation and the photophysical characteristics of chlorin e ₆ in Photolon ointment. We have shown that dimethylsulfoxide and polyethylene glycol 400, in concentrations comparable with their content in the ointment form of the drug Photolon, do not lead to appreciable changes in the spectral characteristics of chlorin e ₆. Substantial changes in the photophysical characteristics of the photosensitizer are observed at significantly higher concentrations of the excipients in the ointment. We have shown that in buffer solution, chlorin e ₆ forms a complex with polyethylene glycol 1500. For the first time, we have detected luminescence of singlet oxygen from the surface of biological tissue treated with Photolon ointment.     

<Emphasis Type="Italic">K</Emphasis><Subscript><Emphasis Type="Italic">e</Emphasis>3</Subscript> decays and CKM unitarity

We present a detailed numerical study of the K_e3 decays to in chiral perturbation theory with virtual photons and leptons. We describe the extraction of the CKM matrix element |V_us| from the experimental K_e3 decay parameters. We propose a consistency check of the K ⁺ _e3 and K⁰_e3 data that is largely insensitive to the dominating theoretical uncertainties, in particular the contributions of . Our analysis is highly relevant in view of the recent high statistics measurement of the K ⁺ _e3 branching ratio by E865 at Brookhaven which does not indicate any significant deviation from CKM unitarity but rather a discrepancy with the present K⁰_e3 data.Received: 22 January 2004, Published online: 30 April 2004Work supported in part by IHP-RTN, Contract No. HPRN-CT2002-00311 (EURIDICE) and by Acciones Integradas, Project No. 19/2003 (Austria), HU2002-0044 (MCYT, Spain)     

Magnetic field effect on free and bound excitons in chalcopyrite CuInS<Subscript>2</Subscript>

The effect of a strong magnetic field (induction up to 10 T) on free and bound excitons in CuInS₂ single crystals is studied. A diamagnetic shift to higher energies is observed in the luminescence and reflectance spectra for free-exciton lines A_LPB ≈ 1.5348 eV, A_UPB ≈ 1.5361 eV, and BC ≈ 1.557 eV. The diamagnetic shifts of free-exciton lines A_LPB, A_UPB, and BC provide a basis for estimating the exciton reduced masses = 0.131m₀, = 0.13 4m₀, and μ_BC = 0.111m₀, respectively. Bound-exciton lines in luminescence spectra are split under the influence of the magnetic field. The magnitude of the Zeeman effect (g-factor of the magnetic splitting) is estimated. __________ Translated from Zhurnal Prikladnoi Spektroskopii Vol. 74, No. 3, pp. 373–377, May–June, 2007.     

The Dynamics of Intramolecular Excited State Relaxation of <Emphasis Type="Italic">N</Emphasis>-Anthryl Substituted Pyridinium Cations

N-(1-Anthryl)-2,4,6-trimethyl-pyridinium (I), N-(2-anthryl)-2,4,6-trimethyl-pyridinium (II) and 10-(1-anthryl)-1,2,3,4,5,6,7,8-octahydro-acridinium cations (III) with anomalously high fluorescence Stokes shift have been investigated. Fluorescence kinetics analysis at various temperatures showed that in the range 293–77 K, the radiative deactivation rate constants (k_f) increase by 5.5 to 30 times. The low-temperature time-resolved emission spectra of I–III were found to be consistent with the model: A A^* B^* where A^* is the local excited twisted form and B^* is the relaxed more planar, bent conformer of the molecule. The rate constants of the excited relaxed state formation (k₁) and back reaction (k_–1) of compounds studied were estimated.     

Structural and thermoelectric properties in (Sb<Subscript>1-x</Subscript>Bi<Subscript>x</Subscript>)<Subscript>2</Subscript>Te<Subscript>3</Subscript> thin films

We have investigated the structural and thermoelectric properties of (Sb_1-xBi_x)₂Te₃ thin films on CdTe(111)B. Analysis of X-ray diffraction patterns (–2 scans and rocking curves) of the films shows that they are of high quality and that they are well aligned with their (00.1) axis normal to the substrates. Measurements of the temperature-dependent thermoelectric power, resistivity, and Hall coefficient of the films were performed with respect to the binary composition, x. For the samples in the range 0.2<x<0.3, the room-temperature thermopower values were in the range 159–184 V/K, the room-temperature carrier concentrations were 3.93–5.13×10¹⁹ cm^-3, and the room-temperature mobilities were 24.6–64.0 cm²V^-1s^-1. PACS 72.20.Pa; 72.80.Jc; 73.6l.Le     

Unusual Pathways of Triplet State Dynamic Relaxation in Meso-Aryl-Substituted Porphyrins and Their Chemical Dimers at 295 K

It was found that mono- and di-meso-phenyl substitution in octaethylporphyrins (OEP)and their chemical dimers with the phenyl ring as a spacer manifests itself in the dramatical shortening of T₁ state lifetimes at 295 K (from 1.5 ms down to 2–5 s in degassed toluene solutions). On the other hand, this substitution does not influence spectral-kinetic parameters of S₀ and S₁ states. The enhancement of the T₁ state non-radiative deactivation is explained by torsional librations of the phenyl ring around a single C-C bond in sterically encumbered OEP molecules leading to non-planar dynamic distorted conformations in the excited T₁ states. For these compounds with electron-accepting NO₂-groups in the meso-phenyl ring the strong non-radiative deactivation of S₁ and T₁ states (by 2–3 orders of magnitude) is observed upon the displacement of NO₂-group from para-to ortho-position of the phenyl ring. The S₁ state quenching is caused by the direct intramolecular electron transfer to low-lying CT state of the radical ion pair (the normal region, non-adiabatic case presumably, V = 130–190 cm^–1 in dimethylformamide). The additional deactivation of the T₁ state is connected with thermally activated transitions to upper-lying CT states as well as the strengthening of intersystem crossing probabilities.     

Applying the <Emphasis FontCategory="NonProportional">POWHEG</Emphasis> method to top-pair production and decays at the ILC

We study the effects of gluon radiation in top-pair production and their decays for e ⁺ e ⁻ annihilation at the ILC. To achieve this we apply the POWHEG method and interface our results to the Monte Carlo event generator . We consider a centre-of-mass energy of GeV and compare decay correlations and bottom-quark and -antiquark distributions before hadronisation.     

Preparation of TiO<Subscript>2</Subscript>-coated LiCo<Subscript>1/3</Subscript>Ni<Subscript>1/3</Subscript>Mn<Subscript>1/3</Subscript>O<Subscript>2</Subscript> by electrostatic self-assembly method and its properties

A precursor of TiO₂–LiCo_1/3Ni_1/3Mn_1/3O₂ was prepared by electrostatic self-assembly method. The final product was obtained by heating the precursor at 400–450 °C for 4–6 h in air. X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and electrochemical tests were used to examine the structural, morphology, elementary valence, and electrochemical characteristics. XRD indicated that the TiO₂-coated material can be indexed by α-NaFeO₂ layered structure, which belongs to hexagonal-type space group R3m. XPS results confirmed the existence of TiO₂ compound on the surface of the coated sample. The SEM image showed that the material had spherically porous morphology with the uniform size about 6 μm. The initial charge–discharge capacity of the TiO₂-coated LiCo_1/3Ni_1/3Mn_1/3O₂ material was 168.8/160.0 mAh/g. After 60 cycles, the discharge capacity of the TiO₂-coated LiCo_1/3Ni_1/3Mn_1/3O₂ sample was 147.0 mAh/g, and the coulombic efficiency was 94.0%. Compared with the uncoated sample, the electrochemical performance of TiO₂-coated LiCo_1/3Ni_1/3Mn_1/3O₂ was improved.     

Final-state polarization in <Emphasis Type="Italic">B</Emphasis><Stack><Subscript><Emphasis Type="Italic">s</Emphasis></Subscript><Superscript>0</Superscript></Stack> decays

Certain B _s ⁰→V ₁ V ₂ decays (V _i is a vector meson) can be related by flavor SU(3) symmetry to corresponding B _d ⁰→V ₃ V ₄ decays. In this paper, we show that the final-state polarization can be predicted in the B _s ⁰ decay, assuming polarization measurements of the B _d ⁰ decay. This can be done within the scenario of penguin annihilation (PA), which has been suggested as an explanation of the unexpectedly large transverse polarization in B→φ K ^*. PA is used to estimate the breaking of flavor SU(3) symmetry in pairs of decays. Two of these for which PA makes a reasonably precise prediction of the size of SU(3) breaking are (B _s ⁰→φ φ,B _d ⁰→φ K ^0*) and ( ). The polarization measurement in the B _d ⁰ decay can be used to predict the transverse polarization in the B _s ⁰ decay and will allow for testing of PA as well as the other assumptions in the analysis.     

Magnetic and transport properties of monocrystalline<Emphasis Type="Italic">Fe</Emphasis><Subscript>3</Subscript><Emphasis Type="Italic">O</Emphasis><Subscript>4</Subscript>

A monocrystal ofFe ₃ O ₄ is characterized by resistance, magnetoresistance and magnetic measurements in a temperature range from 4.2 K to 350 K and magnetic field-cycling from −9 T to 9 T. The resistance measurements revealed a metal-insulator Verwey transition (VT) atT _v =123.76 K with activation energy E=92.5 meV at T >T _v and temperature-substitute for the activation energy below the VT,T ₀=E/k _B ≈3800 K within 70 K–110K. The magnetotransport results independently verified the VT at 123.70 K, with discontinuous change in the magnetic moment ΔM≈0.21 ΔM≈0.21μ _B and resistance hysteresis, dependent on the magnetic field in a narrow temperature range of 0.4° around theT _v . The magnetic characterization established self consistentlyT _v as ≈123.67 K, the jump in the magnetization at the VT≈0.25μ _B and confirmed, that the magnetocrystalline anisotropy is the main microscopic mechanism responsible for the magnetization of the monocrystal (88%) with additional natural and imposed defects contributing as 12%.