Magnetic Circular Dichroism of -Phenyl-Substituted Pd-Octaethylporphyrins.

Absorption and magnetic circular dichroism (MCD) spectra have been measured and theoretically simulated for a series of palladium octaethylporphyrins substituted at the positions with phenyl groups ( = 0-4). Analysis of the spectra included the perimeter model and time-dependent density functional theory (TDDFT) calculations. With the increasing number of phenyl substituents, the molecule is transformed from a positive hard (ΔHOMO > ΔLUMO) to a soft (ΔHOMO ≈ ΔLUMO) chromophore.

The nature of non-FRET photoluminescence quenching in nanoassemblies from semiconductor quantum dots and dye molecules.

Nanoassemblies formed via self-assembly based on colloidal CdSe quantum dots (QDs) and porphyrin (H2P) dye molecules show Fluorescence Resonant Energy Transfer (FRET) and non-FRET quenching of QD photoluminescence (PL). We present a procedure to unravel and quantify these two relaxation pathways via dynamic and static PL quenching experiments. Accordingly, FRET amounts at maximum to 10% of the total quenching efficiency.

[IMPACT OF CASPIAN SEA LEVEL FLUCTUATIONS ON THE EPIZOOTIC ACTIVITY OF THE CASPIAN SANDY NATURAL PLAGUE FOCUS].

There is evidence that in 1923-2014 the sharp aggravations of the epizootic situation of plague in the area of its Caspian sandy natural focus after long interepizootic periods are in time with the ups of the Caspian Sea in the extrema of 11-year solar cycles. There were cases of multiple manifestations of plague in the same areas in the epizootic cycles of 1946-1954, 1979-1996, 2001, and 2013-2014. The paper considers the possible role of amebae of the genus Acanthamoeba and nematodes, the representatives of the orders Rhabditida and Tylenchida in the microfocal pattern of plague manifestations.

Tuning electronic states of a CdSe/ZnS quantum dot by only one functional dye molecule.

Self-assembly of only one functionalized porphyrin dye molecule with one CdSe/ZnS quantum dot (QD) not only modifies the photoluminescence (PL) intensity but also creates a few energetically clearly distinguishable electronic states, opening additional effective relaxation pathways. The related energy modifications are in the range of 10-30 meV and show a pronounced sensitivity to the specific nature of the respective dye. We assign the emerging energies to surface states.

Formation principles and ligand dynamics of nanoassemblies of CdSe quantum dots and functionalised dye molecules.

Functional dye molecules, such as porphyrins, attached to CdSe quantum dots (QDs) through anchoring meso-pyridyl substituents, form quasi-stable nanoassemblies. This fact results in photoluminescence (PL) quenching of the QDs both due to Förster resonance energy transfer (FRET) and the formation of non-radiative surface states under conditions of quantum confinement (non-FRET). The formation process is in competition with the ligand dynamics.

Nanoassemblies designed from semiconductor quantum dots and molecular arrays.

The formation of nanoassemblies of CdSe/ZnS quantum dots (QD) and pyridyl-substituted free-base porphyrin (H(2)P) molecules has been spectroscopically identified by static and time-resolved techniques. The formation of nanoassemblies has been engineered by controlling the type and geometry of the H(2)P molecules. Pyridyl functionalization gives rise to a strong complex formation accompanied by QD photoluminescence (PL) quenching.

Chlorin e6-liposome interaction. Investigation by the methods of fluorescence spectroscopy and inductive resonance energy transfer.

On the basis of spectral fluorescence and polarization measurements and results obtained on the luminescence quenching of the membrane fluorescent probe 1,6-diphenyl-1,3,5-hexatriene (DPH) by incorporated chlorin e6 (chl e6) molecules, it is shown that the interaction of the water-soluble pigment with smaller unilamellar lipid vesicles occurs by a mechanism of partition between the aqueous and lipid phases (partition coefficient Kp = 6.7 x 10(3) and provides rigid fixing of chl e6 monomers at the boundary between the polar and non-polar parts of the lipid membrane. In terms of inductive resonance electronic excitation energy transfer between DPH and chl e6 (R0 = 36.

[Characteristics of complex-formation of chlorine e6 with human and bovine serum albumins].

Pigment-protein complexes of chlorin e6 (Chl e6) with human (HSA) and bovine serum albumines (BSA) have been investigated by spectral-luminescent methods. Fluorescence quenching of tryptophan residues caused by the inductive-resonance energy transfer to pigment molecules and the rise of the polarization degree of Chl e6 emission were observed upon incorporation of Chl e6 in the protein globula. The obtained data on spectral-energetic parameters of protein tryptophanyls and Chl e6 permitted us to calculate the energy transfer critical distances R0 in complexes of Chl e6 with HSA (R0 = 32 A) and BSA (R0 = 35A).

[Characteristics of mixed association and deactivation of electron excitation in chlorophyll-pheophytin complexes].

The regularities of the individual and mixed association of chlorophylls (Chl a, PChl a) with pheophytin (Pheo) were investigated. The complex studies of optical activity, spectral--luminescent and energetic characteristics of aggregates were carried out in mixture of solvents aceton-water (1:49). The formation of pigment mixed associates leads to intracomplex energy transfer from Chl (or PChl) to Pheo.

[Influence of acids and metal salts on associates of pheophytin and its derivatives in binary mixtures of solvents].

The experimental investigation of the influence of HCl and Zn, Cd and Cu acetates on association of pheophytin alpha and rodin g7 was carried out in water-ethanolic (4 : 1) media. It is shown that during acidation of a binary solvent mixtures containing pheophytin alpha associate, the formation of product with the absorption maximum 702nm takes place, which is the pigment associated form. The formation of the same product is found under the action of metal acetates on pigment associated complexes.

[Spectroscopic and photochemical properties of pigments bound to proteins].

Using gel-filtration and spectral-luminescent analysis properties of artificial chlorophyll-protein and chlorine-protein complexes on the basis of human serum albumin (HSA) were analysed. It has been shown that formation of joint complexes pigments - HSA does not induce essential changes in the spectral and energetic parameters of the pigment part of the complex. A change in the rate of photosensitized reduction of methylviologen (sensitizer-pigment) was found during the variation of the relative content of the pigment mixed with HSA.

[Regularities of aggregation and excitation electronic energy transfer in associates of pheophytin and its mesoderivatives].

The spectral-luminescent characteristics of mesoderivatives of pheophytin and its analogs were investigated in binar mixtures of solvents (ethanol--water; dioxane--water). The mesoderivatives were shown not to form stable longwave selfassociates. Under similar conditions the pheophytin mesoderivatives were inclined to the formation of stable mixed associates with pigments, containing vinyl groups and free keto groups in position 9.

[Pathogenetic therapy of cobalt-induced cardiomyopathies].

The pathogenesis of damage to the heart muscle caused by exposure to the effect of cobalt compounds is demonstrated. Agents with various mechanisms of action were tested in the experiment. The most effective pharmacological agents (beta-adrenergic blocking agents, anabolic steroids) are recommended for testing in the clinic.

[Spectral-luminescent properties of separate aggregated forms of pigments in solutions].

The aggregated forms of protochlorophyll a (PChl), 4-vinyl-protochlorophyll a (4VPChl) and chlorophyll a (Chl) in binar mixtures of dioxane-water was investigated. The aggregates are oligomer particles of pigment molecules having considerable degrees of fluorescence polarisation which points to their ordered structure. Two types of fluorescent associates I and II have been discovered.

[Relationship between chlorophyll concentration and the energy reaction between protochlorophyll and chlorophyll in mixed associations].

In the paper results are presented of investigation of protochlorophyll (PChl) and chlorophyll (Chl) mixed associations and of interaction between them within the polymer molecular complex, which forms in mixture of water-dioxane (1 : 4). The initial PChl concentration in all solutions was constant (CPChl = 1 . 10(-5) m/l), and Chl concentration varied from 1.

[Aggregation of 4-vinyl-protochlerophyll and protochlorophyll in solutions].

The addition of water to dioxane solution of protochlorophyll (PChl) and 4-vinyl-protochlorophyll (4VPChl) results in a number of transformations related with pigment molecule associations into polymer formations and with their conversion. By variation of pigment concentration and composition of binar mixture of solvents a set of aggregated forms with different electronic spectra can be obtained. At the first stage the monomeric pigment converts into polymer with long-wavelenght absorption maximum of 633 nm (P633).

[Migration of electron excitation energy in mixed associates of chlorophyll and its derivatives].

The intracomplex migration is investigated of electron excitation energy between molecules which are a part of a mixed associate. Weakly fluorescent and nonfluorescent associates of chlorophyll and its analogues as well as of bacteriochlorophyll and neoxanthine have been used as donors and acceptors. The migration of excitation energy with variation of quantum yield of donor emission from 5-10(-3) to less than or equal to 10(-4) and also with very weak overlapping of luminescence and absorption spectra for the pair D leads to A is experimentally discovered by luminescence excitation spectra of mixed pigment aggregates.