Old age as a basic concept of social gerontology: Linguistic-theoretical aspect

This article examines the views of modern scientists on the phenomenon of old age, as well as the range of problems and concepts of special social science –gerontology, designed to solve demographic, socio-economic problems of aging. It is noted that social gerontology, which is a branch of the abovementioned science, also relates to the group of sciences of the linguistic cycle: culture of speech, stylistics, sociolinguistics and others. It is pointed out that the speeches of elderly people are characterised by specific lexical units and idiomatic expressions. Issues related to the old age and the ageing of man since ancient times have been in the focus of philosophers' attention. The article mentions the works of the famous statesman of the Roman Empire, politician, philosopher and orator Mark Tullius Cicero (106-43). The author concludes that the integration of social gerontology with linguistic science may lead to the emergence of a new scientific field, that will possibly be named linguistic gerontology or gerontological linguistics

Anisotropic Magnetoresistance in Ga1−x_{1-x}Mnx_xAs

We have measured the magnetoresistance in a series of Ga$_{1-x}$Mn$_x$As samples with 0.033$\le x \le$ 0.053 for three mutually orthogonal orientations of the applied magnetic field. The spontaneous resistivity anisotropy (SRA) in these materials is negative (i.e. the sample resistance is higher when its magnetization is perpendicular to the measuring current than when the two are parallel) and has a magnitude on the order of 5% at temperatures near 10K and below. This stands in contrast to the results for most conventional magnetic materials where the SRA is considerably smaller in magnitude for those few cases in which a negative sign is observed. The magnitude of the SRA drops from its maximum at low temperatures to zero at T$_C$ in a manner that is consistent with mean field theory. These results should provide a significant test for emerging theories of transport in this new class of materials.Comment: 4 pages with 4 figures. Submitted to Physical Review

Creation of multiple nanodots by single ions

In the challenging search for tools that are able to modify surfaces on the nanometer scale, heavy ions with energies of several 10 MeV are becoming more and more attractive. In contrast to slow ions where nuclear stopping is important and the energy is dissipated into a large volume in the crystal, in the high energy regime the stopping is due to electronic excitations only. Because of the extremely local (< 1 nm) energy deposition with densities of up to 10E19 W/cm^2, nanoscaled hillocks can be created under normal incidence. Usually, each nanodot is due to the impact of a single ion and the dots are randomly distributed. We demonstrate that multiple periodically spaced dots separated by a few 10 nanometers can be created by a single ion if the sample is irradiated under grazing angles of incidence. By varying this angle the number of dots can be controlled.Comment: 12 pages, 6 figure

Structural and electronic properties of 2D (graphene, hBN)/H-terminated diamond (100) heterostructures

We report a first-principles study of the structural and electronic properties of two-dimensional (2D) layer/hydrogen-terminated diamond (100) heterostructures. Both the 2D layers exhibit weak van-der-Waals (vdW) interactions and develop rippled configurations with the H-diamond (100) substrate to compensate for the induced strain. The adhesion energy of the hexagonal boron nitride (hBN) layer is slightly higher, and it exhibits a higher degree of rippling compared to the graphene layer. A charge transfer analysis reveals a small amount of charge transfer from the H-diamond (100) surface to the 2D layers, and most of the transferred charge was found to be confined within the vdW gap. In the graphene/H-diamond (100) heterostructure, the semi-metallic characteristic of the graphene layer is preserved. On the other hand, the hBN/H-diamond (100) heterostructure shows semiconducting characteristics with an indirect bandgap of 3.55 eV, where the hBN layer forms a Type-II band alignment with the H-diamond (100) surface. The resultant conduction band offset and valence band offset are 0.10 eV and 1.38 eV, respectively. A thin layer of hBN offers a defect-free interface with the H-diamond (100) surface and provides a layer-dependent tunability of electronic properties and band alignment for surface-doped diamond field effect transistors

Development and characterisation of a large diameter decellularised vascular allograft

The aims of this study were to develop a biological large diameter vascular graft by decellularisation of native human aorta to remove the immunogenic cells whilst retaining the essential biomechanical, and biochemical properties for the ultimate benefit of patients with infected synthetic grafts. Donor aortas (n = 6) were subjected to an adaptation of a propriety decellularisation process to remove the cells and acellularity assessed by histological analysis and extraction and quantification of total DNA. The biocompatibility of the acellular aortas was determined using standard contact cytotoxicity tests. Collagen and denatured collagen content of aortas was determined and immunohistochemistry was used to determine the presence of specific extracellular matrix proteins. Donor aortas (n = 6) were divided into two, with one half subject to decellularisation and the other half retained as native tissue. The native and decellularised aorta sections were then subject to uniaxial tensile testing to failure [axial and circumferential directions] and suture retention testing. The data was compared using a paired t-test. Histological evaluation showed an absence of cells in the treated aortas and retention of histoarchitecture including elastin content. The decellularised aortas had less than 15 ng mg¯¹ total DNA per dry weight (mean 94% reduction) and were biocompatible as determined by in vitro contact cytotoxicity tests. There were no gross changes in the histoarchitecture [elastin and collagen matrix] of the acellular aortas compared to native controls. The decellularisation process also reduced calcium deposits within the tissue. The uniaxial tensile and suture retention testing revealed no significant differences in the material properties (p > 0.05) of decellularised aorta. The decellularisation procedure resulted in minimal changes to the biological and biomechanical properties of the donor aortas. Acellular donor aorta has excellent potential for use as a large diameter vascular graft

The epitaxy of 2D materials growth

Two dimensional (2D) materials consist of one to a few atomic layers, where the intra-layer atoms are chemically bonded and the atomic layers are weakly bonded. The high bonding anisotropicity in 2D materials make their growth on a substrate substantially different from the conventional thin film growth. Here, we proposed a general theoretical framework for the epitaxial growth of a 2D material on an arbitrary substrate. Our extensive density functional theory (DFT) calculations show that the propagating edge of a 2D material tends to align along a high symmetry direction of the substrate and, as a conclusion, the interplay between the symmetries of the 2D material and the substrate plays a critical role in the epitaxial growth of the 2D material. Based on our results, we have outlined that orientational uniformity of 2D material islands on a substrate can be realized only if the symmetry group of the substrate is a subgroup of that of the 2D material. Our predictions are in perfect agreement with most experimental observations on 2D materials&apos; growth on various substrates known up to now. We believe that this general guideline will lead to the large-scale synthesis of wafer-scale single crystals of various 2D materials in the near future. Advances in our ability to manipulate genetics leads to deeper understanding of biological systems. In this perspective, the authors argue that synthetic genomics facilitates complex modifications that open up new areas of research

Old age as a basic concept of social gerontology: Linguistic-theoretical aspect

This article examines the views of modern scientists on the phenomenon of old age, as well as the range of problems and concepts of special social science –gerontology, designed to solve demographic, socio-economic problems of aging. It is noted that social gerontology, which is a branch of the abovementioned science, also relates to the group of sciences of the linguistic cycle: culture of speech, stylistics, sociolinguistics and others. It is pointed out that the speeches of elderly people are characterised by specific lexical units and idiomatic expressions. Issues related to the old age and the ageing of man since ancient times have been in the focus of philosophers' attention. The article mentions the works of the famous statesman of the Roman Empire, politician, philosopher and orator Mark Tullius Cicero (106-43). The author concludes that the integration of social gerontology with linguistic science may lead to the emergence of a new scientific field, that will possibly be named linguistic gerontology or gerontological linguistics

Raman microscopy of phthalocyanines in cells

The results are presented of the study of intracellular localization of Co-phthalocyanines. The methods were used of Raman and fluorescence microspectroscopy