Study of highly defective titanium dioxide prepared via pulsed laser ablation

TiO2 powder was synthesized in the following way. At first, a colloidal solution of Ti in distilled water was obtained by PLA using Nd:YAG laser (wavelength of 1064 nm, frequency of 20 Hz, pulse duration of 7 ns). Then the colloidal solution was dried at 60 °C. After that, the powder was annealed at different temperatures

Psychology of Mobbing as a Form of Conflict in the Workplace: Finding and Testing Project-Based Learning in Students’ Education

Project-based learning has long been used in universities when preparing students. However, project-based technologies are currently being increasingly used in work with students. The authors found various options for the application of these technologies in teaching psychological and pedagogical disciplines. The research aims to determine the practice of implementing project-based learning to provide a deeper practice-oriented understanding of academic disciplines. The authors use a set of methods of theoretical analysis and practical psychological techniques. The authors present the research results in the form of several generalizations. The first one concerns the fact that mobbing has recently become a stable trend in teams; a conflict often manifests itself in the form of mobbing. The study of various organizational cultures and their models shows that the optimal and morally oriented model of organizational culture is the barrier preventing the development of mobbing in the company. The practical application of the developed theory provides methodological support for training a successful specialist

Deinococcus geothermalis: The Pool of Extreme Radiation Resistance Genes Shrinks

Bacteria of the genus Deinococcus are extremely resistant to ionizing radiation (IR), ultraviolet light (UV) and desiccation. The mesophile Deinococcus radiodurans was the first member of this group whose genome was completely sequenced. Analysis of the genome sequence of D. radiodurans, however, failed to identify unique DNA repair systems. To further delineate the genes underlying the resistance phenotypes, we report the whole-genome sequence of a second Deinococcus species, the thermophile Deinococcus geothermalis, which at its optimal growth temperature is as resistant to IR, UV and desiccation as D. radiodurans, and a comparative analysis of the two Deinococcus genomes. Many D. radiodurans genes previously implicated in resistance, but for which no sensitive phenotype was observed upon disruption, are absent in D. geothermalis. In contrast, most D. radiodurans genes whose mutants displayed a radiation-sensitive phenotype in D. radiodurans are conserved in D. geothermalis. Supporting the existence of a Deinococcus radiation response regulon, a common palindromic DNA motif was identified in a conserved set of genes associated with resistance, and a dedicated transcriptional regulator was predicted. We present the case that these two species evolved essentially the same diverse set of gene families, and that the extreme stress-resistance phenotypes of the Deinococcus lineage emerged progressively by amassing cell-cleaning systems from different sources, but not by acquisition of novel DNA repair systems. Our reconstruction of the genomic evolution of the Deinococcus-Thermus phylum indicates that the corresponding set of enzymes proliferated mainly in the common ancestor of Deinococcus. Results of the comparative analysis weaken the arguments for a role of higher-order chromosome alignment structures in resistance; more clearly define and substantially revise downward the number of uncharacterized genes that might participate in DNA repair and contribute to resistance; and strengthen the case for a role in survival of systems involved in manganese and iron homeostasis

Highly defective dark nano titanium dioxide: preparation via pulsed laser ablation and application

The development of methods to synthesize and study the properties of dark titania is of the utmost interest due to prospects for its use, primarily in photocatalysis when excited by visible light. In this work, the dark titania powder was prepared by pulsed laser ablation (Nd:YAG laser, 1064 nm, 7 ns) in water and dried in air. To study the changes occurring in the material, the thermal treatment was applied. The structure, composition, and properties of the obtained powders were studied using transmission electron microscopy, low-temperature N2 adsorption/desorption, X-ray diffraction, thermogravimetry/differential scanning calorimetry, X-ray photoelectron, Raman and UV-vis spectroscopies, and photoluminescence methods. The processes occurring in the initial material upon heating were studied. The electronic structure of the semiconductor materials was investigated, and the nature of the defects providing the visible light absorption was revealed. The photocatalytic and antibacterial activities of the materials obtained were also studied. Dark titania obtained via laser ablation in liquid was found to exhibit catalytic activity in the phenol photodegradation process under visible light (>420 nm) and showed antibacterial activity against Staphylococcus aureus and bacteriostatic effect towards Escherichia coli. View Full-Tex

Effect of laser and temperature treatment on the optical properties of titanium dioxide nanoparticles prepared via pulsed laser ablation

Nanomaterials based on titanium dioxide are of considerable interest as promising photocatalysts for water and air purification and hydrogen generation. To increase the efficiency of TiO2, it is necessary to extend the spectral range of its absorption to the visible region. In this work, nanocolloids of dark titanium dioxide, initially prepared by pulsed laser ablation (Nd:YAG laser, 1064 nm, 7 ns) in water, are subjected to an additional laser treatment from the same source. Colloidal solutions are dried and TiO2 powders are annealed. A comparative analysis of the optical properties of the materials prepared with and without extra treatment by the methods of diffuse reflection spectroscopy, fluorescence, and Raman spectroscopy is carried out. The bandgap of the materials is estimated, and the nature of the defect states responsible for intense absorption in the visible region of the spectrum is determine

Experimental approach to study the effect of mutations on the protein folding pathway.

Is it possible to compare the physicochemical properties of a wild-type protein and its mutant form under the same conditions? Provided the mutation has destabilized the protein, it may be more correct to compare the mutant protein under native conditions to the wild-type protein destabilized with a small amount of the denaturant. In general, is it appropriate to compare the properties of proteins destabilized by different treatments: mutations, pH, temperature, and denaturants like urea? These issues have compelled us to search for methods and ways of presentation of experimental results that would allow a comparison of mutant forms of proteins under different conditions and lead to conclusions on the effect of mutations on the protein folding/unfolding pathway. We have studied equilibrium unfolding of wild-type bovine carbonic anhydrase II (BCA II) and its six mutant forms using different urea concentrations. BCA II has been already studied in detail and is a good model object for validating new techniques. In this case, time-resolved fluorescence spectroscopy was chosen as the basic research method. The main features of this experimental method allowed us to compare different stages of unfolding of studied proteins and prove experimentally that a single substitution of the amino acid in three mutant forms of BCA II affected the native state of the protein but did not change its unfolding pathway. On the contrary, the inserted disulfide bridge in three other mutant forms of BCA II affected the protein unfolding pathway. An important result of this research is that we have validated the new approach allowing investigation of the effect of mutations on the folding of globular proteins, because in this way it is possible to compare proteins in the same structural states rather than under identical conditions

The adoption of e-learning technology at the faculty of distance learning of Plekhanov Russian University of Economics

The authors review application of information technologies and systems at the Faculty of Distance Learning of Plekhanov Russian University of Economics. General aspects of organizing training in e-learning environment, highlighting the advantages and disadvantages of such approach are also examined. The authors study and analyze a number of surveys of students about the effectiveness of the distance learning. They were conducted in the format of Questionnaire seeking feedback on the effectiveness of various approaches in distance learning. This article helps better understand the value of e-learning and other innovative forms of delivering educational materials to students in the context of higher education and confirms the overall positive attitude of students and faculty members towards the use of online and e-learning modules/methods. The research clearly shows the trend and ongoing transition from traditional forms of learning to learning based on information technologies and systems