Detection of nanodiamonds in biological samples by EPR spectrometry

In model experiments in vitro, the applicability of the EPR spectrometry method for the detection of modified nanodiamonds (MNDs) in blood and homogenates of mouse organs has been established. A characteristic signal (g = 2.003, ΔH ≈ 10 G) is observed in the samples of biomaterials containing MNDs, the intensity of which increases linearly with the concentration of nanoparticles in the range of 1.6–200 μg MNDs per 1 mL of the sample. The EPR method in biomaterials reveals the presence of intrinsic paramagnetic centers, signals from which are superimposed on the signal from the MNDs. However, the intensity of these signals is small, which makes it possible to register the MNDs using EPR spectrometry with the necessary accuracy. The data obtained open up the prospects of using the EPR method for studies of the interorgan distribution, accumulation, and elimination of MNDs during their intravenous injection into experimental animals.     

Selective Electroreduction of CO2 toward Ethylene on Nano Dendritic Copper Catalysts at High Current Density

In situ deposited copper nanodendrites are herein proven to be a highly selective electrocatalyst which is capable of reducing CO₂ to ethylene by reaching a Faradaic efficiency of 57% at a current density of 170 mA cm^?2. It is found that the desired structures are formed in situ under acidic pH conditions at high electrode potentials more negative than ?2 V versus Ag/AgCl. Detailed investigations on the preparation, characterization, and advancement of electrode materials and of the electrolyte have been performed. Catalyst degradation effects are intensively followed by scanning electron microscopy (SEM) and high‐resolution transmission electron microscopy (HR‐TEM) characterization methods and found to be a major root course for selectivity losses.     

Synthesis and biological properties of polysaccharide-peptide conjugates as potential antigens for a vaccine against meningococci of serogroups A and B

A new approach to the development of a vaccine against meningococci of serogroups A and B was proposed. It involves the synthesis of conjugates of high-molecular capsule polysaccharides of the serogroup A meningococcus (PsA) with earlier synthesized protective fragments of membrane proteins from serogroup B meningococci. The conjugates were synthesized using a method that consists of the generation of aldehyde groups by oxidizing free vicinal hydroxyl groups of PsA and subsequent reaction of these groups with amino groups of the peptide. The reaction proceeds with the intermediate formation of the Schiff base, which is reduced to the stable secondary amine. The main parameters of the reaction were optimized in the synthesis of a PsA conjugate with a model peptide and methods of their characterization were developed. The reproducibility and efficiency of the synthetic procedure were demonstrated by the example of synthesis of PsA conjugates with fragments of protein PorA from the outer membrane of the serogroup B meningococcus. It was shown that, when administered without adjuvant, a conjugate of PsA with a protective peptide, which represents an exposed conserved fragment 306–332 of protein PorA, stimulates the formation of antibodies to the peptide and polysaccharide moieties of the molecule and is also capable of decreasing the degree of bacteremia in animals infected with serogroup A and serogroup B meningococci. The approach can be applied to the development of a complex vaccine for serogroup A and serogroup B meningococci.     

Influence of Position and Size of Substituents on the Mechanism of Partitioning: A Thermodynamic Study on Acetaminophens,Hydroxybenzoic Acids,and Parabens

The objective of the present investigation was to study the influence of size, nature, and topology of substituents on the thermodynamic characteristics of sublimation, fusion, solubility, solvation, and partitioning processes of some drug and druglike molecules. Thermodynamic functions of sublimation process 2-acetaminophen and 3-acetaminophen were obtained on the basis of temperature dependencies of vapor pressure by the transpiration method. Thermodynamic characteristics of solubility processes in water, n-octanol, and n-hexane were calculated from the temperature dependencies of solubility using the solubility saturation method. For evaluation of fusion parameters, differential scanning calorimetry was used. A new approach to distinguishing specific and nonspecific energetic terms in the crystal lattice was developed. Specific and nonspecific solvation terms were distinguished using the transfer from the “inert” n-hexane to the other solvents. For the acetaminophen compounds and for some related drug molecules, the correlation between melting points and a parameter describing the ratio between specific and nonspecific interaction in the crystal lattices was obtained. A diagram enabling analysis of the mechanism of the partitioning process was applied. It was found that for isomers of benzoic acids and for acetaminophens, the position of substituents affects the mechanism of the partitioning process but not the extent of partitioning ( values). In contrast to this, an increased size of substituents (parabens) leads to essential changes in values, but the mechanism of the partitioning process stays the same.     

Current features of HIV-infection in St. Petersburg

Dynamics of HIV-infection epidemic in St. Petersburg was analyzed. New features of epidemic process, which were not observed in St. Petersburg earlier, whereas noted in other territories of Russia, were revealed and described.     

The seashore sedges of the Russian Kola Peninsula: How many species?

A necessary basis for environmental protection is thorough knowledge of the biodiversity to be protected. Setting conservation priorities in taxonomically complex groups is an especially difficult task. The seashore sedges of the Carex salina group (Cyperaceae) of the Russian White and Barents Seas form important parts of the coastal ecosystems and include species listed as rare and endangered. However, their taxonomy is poorly understood and supposed to be blurred by hybridization, also including the closely related C. aquatilis and possibly other species of sect. Phacocystis (C. bigelowii, C. nigra s. lat.). We address the taxonomic situation in the C. salina group in the Kola Peninsula with emphasis on taxa of supposed hybrid origin (C. salina and C. recta coll.). We analyzed 92 plants from 28 sites for 101 amplified fragment length polymorphisms (AFLPs) and 10 morphological characters. The plants referred to three supposedly “pure” species (C. aquatilis, C. paleacea and C. subspathacea) formed different extreme parts of the morphological and molecular variation. These species could be discriminated by a combination of morphological characters. The two taxa of proposed hybrid origin had extremely variable morphology and could not be clearly distinguished from each other or from the supposedly “pure” species. Our results demonstrate extensive gene flow between all taxa, suggesting that the entire C. salina group including C. aquatilis acts as a single large biological species.     

Self-organization of endoplasmic reticulum aggregates in cells with overexpression of nucleoporin POM121

The nuclear pore complexes are complex protein structures located in the nuclear envelope, where they control the nuclear-cytoplasmic transport, and inside the stacks of endoplasmic reticulum cisternae, annulate lamellae. After overexpression of some nucleoporins, numerous granules are visible in the cytoplasm. According to the published data, these granules are the annulate lamellae. In the current paper, the structural organization of POM121-containing granules was analyzed using correlative light and electron microscopy. The ultrastructural study demonstrates that POM121-containing granules are not annulate lamellae but aggregates of endoplasmic reticulum membranes. Thus, overexpressed POM121 is not able to induce the annulate lamella formation. The mechanisms of self-organization of non-functional structures (such as the aggregates of endoplasmic reticulum membranes described here) and possible involvement of these mechanisms in the formation of cellular structures are discussed.