Determination of the concentration of impurities in GaN from photoluminescence and secondary-ion mass spectrometry.

Photoluminescence (PL) was used to estimate the concentration of carbon in GaN grown by hydride vapor phase epitaxy (HVPE). The PL data were compared with profiles of the impurities obtained from secondary ion mass spectrometry (SIMS) measurements. Comparison of PL and SIMS data has revealed that apparently high concentrations of C and O at depths up to 1 µm in SIMS profiles do not represent depth distributions of these species in the GaN matrix but are rather caused by post-growth surface contamination and knocking-in impurity species from the surface.

Elucidating Binding Sites and Affinities of ERα Agonists and Antagonists to Human Alpha-Fetoprotein by In Silico Modeling and Point Mutagenesis.

Alpha-fetoprotein (AFP) is a major embryo- and tumor-associated protein capable of binding and transporting a variety of hydrophobic ligands, including estrogens. AFP has been shown to inhibit estrogen receptor (ER)-positive tumor growth, which can be attributed to its estrogen-binding ability. Despite AFP having long been investigated, its three-dimensional (3D) structure has not been experimentally resolved and molecular mechanisms underlying AFP-ligand interaction remains obscure.

Novel heterocyclic chitosan derivatives and their derived nanoparticles: Catalytic and antibacterial properties.

The metal-assisted nitrone-nitrile cycloaddition reaction is apply to empower chitosan chemistry. The ultrasonic irradiation has proven to efficiently accelerate the cycloaddition affording new heterocyclic (1,2,4-oxadiazoline) chitosan derivatives and avoiding ultrasonic degradation of the chitosan macromolecules. By varying the nitrone nature, both water- and toluene-soluble chitosan derivatives were successfully synthesized.

Treatment of Basal Cell Cancer With a Pulsed Copper Vapor Laser: A Case Series.

Basal cell carcinoma (BCC) is the most prevalent form of non-melanoma skin cancer commonly arising in elderly patients. Currently, many laser systems are applied for the treatment of BCC. However, up to the present, there have been several reports concerning ocular side effects due to the laser procedure in the borders of the periorbital area.

Ultrasound-assisted catalyst-free thiol-yne click reaction in chitosan chemistry: Antibacterial and transfection activity of novel cationic chitosan derivatives and their based nanoparticles.

In this work, we demonstrate that the thiol-yne click reaction could be efficiently mediated by ultrasonic irradiation and implement the ultrasound-assisted thiol-yne click reaction to chitosan chemistry as a polymer-analogous transformation. We optimize power and frequency of ultrasound to preserve selectivity of the click reaction and avoid ultrasonic degradation of the chitosan polymer chain. Thus, we obtain a new water-soluble betaine.

Adaptation, fitness landscape learning and fast evolution.

We consider evolution of a large population, where fitness of each organism is defined by many phenotypical traits. These traits result from expression of many genes. Under some assumptions on  fitness we prove that such model organisms  are capable, to some extent, to recognize the fitness landscape.

Oxidative Stress and Advanced Lipoxidation and Glycation End Products (ALEs and AGEs) in Aging and Age-Related Diseases.

Oxidative stress is a consequence of the use of oxygen in aerobic respiration by living organisms and is denoted as a persistent condition of an imbalance between the generation of reactive oxygen species (ROS) and the ability of the endogenous antioxidant system (AOS) to detoxify them. The oxidative stress theory has been confirmed in many animal studies, which demonstrated that the maintenance of cellular homeostasis and biomolecular stability and integrity is crucial for cellular longevity and successful aging. Mitochondrial dysfunction, impaired protein homeostasis (proteostasis) network, alteration in the activities of transcription factors such as Nrf2 and NF-B, and disturbances in the protein quality control machinery that includes molecular chaperones, ubiquitin-proteasome system (UPS), and autophagy/lysosome pathway have been observed during aging and age-related chronic diseases.

Novel non-toxic high efficient antibacterial azido chitosan derivatives with potential application in food coatings.

In this work, we developed a simple method for the preparation of N-(3-azido-2-hydroxypropyl)chitosan. We compared the antibacterial activity of N-(3-azido-2-hydroxypropyl)chitosans and previously synthesized N-(2-azidoethyl)chitosans. N-(3-azido-2-hydroxypropyl)chitosans possess higher antibacterial effect which is comparable with that of ampicillin and gentamicin.

Population genetic analysis of trematode Parasaccocoelium mugili Zhukov, 1971 (Haploporidae Nicoll, 1914) from the Russian Far East and Vietnam based on ribosomal ITS and mitochondrial COI gene partial sequence data.

Intraspecific variation of Parasaccocoelium mugili collected from mullet fish of the south of Russian Far East and Vietnam has previously been estimated on the basis of two molecular markers: ribosomal internal transcribed spacer 1 (ITS1) rDNA and mitochondrial cytochrome oxidase I (COI) gene sequences. In the present study, molecular identification of this species from the Kievka River, Primorye and from Vietnam was performed by analysis of 28S rDNA sequences. Analysis of ITS1 rDNA sequences variation revealed two highly differentiated main groups, representing trematode specimens from the two regions.

Ultrasound-assisted catalyst-free phenol-yne reaction for the synthesis of new water-soluble chitosan derivatives and their nanoparticles with enhanced antibacterial properties.

This work describes ultrasound-assisted phenol-yne addition of p-hydroxybenzaldehyde and propargylic ester of betaine hydrochloride giving only 2-((3-(4-formylphenoxy)allyl)oxy)-N,N,N-trimethyl-2-oxoethan-1-aminium chloride as a product at 100kHz 300W in water. The ultrasonic assisted phenol-yne addition was enhanced to chitosan chemistry. Phenolic chitosan derivatives were obtained by treatment of chitosan with o-, m- or p-hydroxybenzaldehyde followed by reduction of the formed CN bound by NaBH.

Rhinophyma Treatment by Copper Vapor Laser With the Computerized Scanner.

Rhinophyma is recognized as a common and severe skin disease manifested as progressive thickening of the nasal skin due to hypertrophy of the soft tissue. The most severe complication of rhinophyma is telangiectasis. So far the pathogenetic approach for the treatment of rhinophyma should be based on the removal of the dysplastic vessels to provide the appropriate revascularization of the involved skin area.

Numerical Modeling and Clinical Evaluation of Pulsed Dye Laser and Copper Vapor Laser in Skin Vascular Lesions Treatment.

Different yellow lasers have been successfully used for the treatment of vascular lesions. This study is aimed to ascertain the role and efficiency of copper vapor lasers (CVLs) and pulsed dye lasers (PDLs) for the treatment of vascular lesions using numerical modeling and to compare results with our clinical experience. In this study we aimed to develop criteria for the choice of more efficient laser exposure mode, investigate more relevant modes of laser irradiation to ensure selective photothermolysis of target vessels, and compare the CVL and PDL efficiency in the course of patients with skin vascular lesions (SVL) treatment.

[Characteristics of thinking recorded in experimental psychological studies of young people].

Aim: To identify the features of thinking of young people, whose mental development was carried out in conditions of life virtualization (in a networked society).

Material And Methods: The study included 310 mentally healthy respondents, aged from 18 to 20 years, who study in universities of St. Petersburg.

Stable Deuterium Labeling of Histidine-Rich Lysine-Based Dendrimers.

Peptide dendrimers, due to their biocompatibility and low toxicity, are highly promising candidates as nanocarriers for drugs and genes. The development of this kind of delivery system requires reliable monitoring of their metabolic and biological pathways. In this respect, hydrogen isotope labeling has tremendous importance, being a safe tool for detection of the labeled nanocarriers.

Modelling of the heat accumulation process during short and ultrashort pulsed laser irradiation of bone tissue.

An analytical model is presented that qualitatively describes the cooling of a biological tissue after irradiation with short and ultrashort laser pulses. The assumption that the distribution of temperature at the initial moment of surface cooling repeats the distribution of the absorbed laser energy allowed us to use the thermal conductivity approximation in both cases. The experimental results of irradiation of dry bone with nanosecond and femtosecond laser pulses are compared with the calculated data.

Ultrasound-assisted Cu(I)-catalyzed azide-alkyne click cycloaddition as polymer-analogous transformation in chitosan chemistry. High antibacterial and transfection activity of novel triazol betaine chitosan derivatives and their nanoparticles.

In this work, we involved ultrasound-assisted click CuAAC in chitosan chemistry. Ultrasound-mediated CuAAC between propargylic ester of betaine and azido chitosan derivative proceeds fast in water under aerobic conditions and gives rise novel water-soluble triazole betaine chitosan derivatives. Using ionic gelation technique, we prepared and characterized nanoparticles from the synthesized chitosan derivatives.

Investigation of effective media applicability for ultrathin multilayer structures.

Multilayer hyperbolic metamaterials (HMMs) are highly anisotropic media consisting of alternating metal and dielectric layers with their electromagnetic properties defined by the effective medium approximation (EMA). EMA is generally applied for a large number of subwavelength unit cells or periods of a multilayer HMM. However, in practice, the number of periods is limited.

Natural polysaccharide-based smart (temperature sensing) and active (antibacterial, antioxidant and photoprotective) nanoparticles with potential application in biocompatible food coatings.

Smart and active nanoparticles are of increasing interest in food films and coatings application. In the current study, we purpose novel nanoparticles NPs-4 and NPs-4, which possess simultaneously both smart (temperature sensitive) and active (antibacterial, light absorbing and antioxidant) properties. The obtained nanoparticles are based on PEG/MC core with anthocyanidin and sodium acetate, and chitosan/gallotannin-based shell.

Synthesis of novel 1H-tetrazole derivatives of chitosan via metal-catalyzed 1,3-dipolar cycloaddition. Catalytic and antibacterial properties of [3-(1H-tetrazole-5-yl)ethyl]chitosan and its nanoparticles.

New tetrazole derivatives of chitosan with low, moderate, and high degrees of substitution were obtained using a novel approach, i.e. metal-catalyzed 1,3-dipolar cycloaddition of azide ion to cyanoethyl chitosan in water - the most straightforward, selective and preparatively convenient route to tetrazole chitosan derivatives.

Data-Rate Constrained Observers of Nonlinear Systems.

In this paper, the design of a data-rate constrained observer for a dynamical system is presented. This observer is designed to function both in discrete time and continuous time. The system is connected to a remote location via a communication channel which can transmit limited amounts of data per unit of time.

Nicotinamide riboside has protective effects in a rat model of mesenteric ischaemia-reperfusion.

Acute mesenteric ischaemia is a syndrome caused by inadequate blood flow through the mesenteric vessels, resulting in ischaemia and eventual gangrene of the bowel wall. Although relatively rare, it is a potentially life-threatening condition. The maintenance of haemodynamic stability, along with adequate oxygen saturation, and the correction of any electrolyte imbalance, are of the utmost importance.

[Investigation of internet-communities' influence on the social inclusion of the elderly people through leisure practices.].

Modern society is characterized by the intensification of new interactions and new communities, in parallel with the interest in social exclusion-inclusion topic. As the Internet develops, the research interest is directed to studying the specifics of emerging communities in a virtual environment called as «online communities», «virtual communities» etc. The article presents the results of studying 7 online communities of older people in the social network VKontakte about leisure.

A new subfamily, Pseudohaploporinae subfam. n. (Digenea: Haploporidae), with morphometric and molecular analyses of two new species: Pseudohaploporus vietnamensis n. g., sp. n. and Pseudohaploporus planilizum n. g., sp. n. from Vietnamese mullet.

Adult specimens representing Pseudohaploporus vietnamensis n. g., sp.

Porous Inorganic Carriers Based on Silica, Calcium Carbonate and Calcium Phosphate for Controlled/Modulated Drug Delivery: Fresh Outlook and Future Perspectives.

Porous inorganic nanostructured materials are widely used nowadays as drug delivery carriers due to their adventurous features: suitable architecture, large surface area and stability in the biological fluids. Among the different types of inorganic porous materials, silica, calcium carbonate, and calcium phosphate have received significant attention in the last decade. The use of porous inorganic materials as drug carriers for cancer therapy, gene delivery etc.

Dynamics of nonlinear Schrödinger breathers in a potential trap.

We consider the evolution of the 2-soliton (breather) of the nonlinear Schrödinger equation on a semi-infinite line with the zero boundary condition and a linear potential, which corresponds to the gravity field in the presence of a hard floor. This setting can be implemented in atomic Bose-Einstein condensates, and in a nonlinear planar waveguide in optics. In the absence of the gravity, repulsion of the breather from the floor leads to its splitting into constituent fundamental solitons, if the initial distance from the floor is smaller than a critical value; otherwise, the moving breather persists.