Coherent Cherenkov radiation as an intense THz source

Diffraction and Cherenkov radiation of relativistic electrons from a dielectric target has been proposed as mechanism for production of intense terahertz (THz) radiation. The use of an extremely short high-energy electron beam of a 4th generation light source (X-ray free electron laser) appears to be very promising. A moderate power from the electron beam can be extracted and converted into THz radiation with nearly zero absorption losses. The initial experiment on THz observation will be performed at CLARA/VELA FEL test facility in the UK to demonstrate the principle to a wider community and to develop the radiator prototype. In this paper, we present our theoretical predictions (based on the approach of polarization currents), which provides the basis for interpreting the future experimental measurements. We will also present our hardware design and discuss a plan of the future experiment

The role of chlorophyll in determining the resistance of soybean plants to prolonged soil flooding

Prolonged inundation of soybean plants leads to their death because of root hypoxia. Therefore, the search for markers of resistance to this factor will provide the opportunity to develop the varieties able to resist this stress. The research was aimed at the study of response of 3 varieties bred by Federal Research Center All-Russian Scientific Research Institute of Soybean to prolonged flooding according to the indicator of chlorophyll a and b content in soybean leaves. The study was carried out in 2019-2021 in laboratory experiments when growing plants on hydroponic installations with 24-day soil flooding (control - soil with optimal moisture content). In soybean varieties Evgeniya and Kukhanna, registered as resistant to overwatering soil, the response by content of chlorophyll forms in leaves under 24-day flooding of the soil surface with 1-2 cm layer of water differed. It was found that increase of chlorophyll a in leaves of Evgeniya variety under flooding was connected with providing the ability of this variety plants to resist the stressful flooding factor. The presence of chlorophyll b in the leaves of this variety before the ripeness phase indicates that it can serve as an indicator of plant resistance to root hypoxia to a greater extent, since the plants continued to grow and develop. In the Kukhanna variety, the content of both forms of chlorophyll at optimum soil moisture of the control variety was higher or at the same level as in the variant with flooding, that cannot serve as the criterion of resistance of this variety to root hypoxia. In the Kitrossa variety, the resistance of which to overwatering has not been noted by the breeders yet there were revealed wavy fluctuations in chlorophyll a/b ratio during the first 10 days of flooding. The fluctuations were caused by changes in the content of chlorophyll b, the concentration of which increased first and then decreased. This fluctuation is most clearly seen in the graph of the change in the ratio between chlorophyll a and b, that may serve as a marker for determination of resistance of soybean varieties to prolonged soil flooding

Analysis of genetic relationships of genotypes of the genus Rosa L. from the collection of Nikita Botanical Gardens using ISSR and IRAP DNA markers

In connection with the development of breeding and the creation of new plant varieties, the problem of their genotyping and identification is becoming increasingly important, therefore the use of molecular methods to identify genetic originality and assess plant genetic diversity appears to be relevant. As part of the work performed, informative ISSR and IRAP DNA markers promising for the study of genetic diversity of the Rosa L. genus were sought and applied to analysis of genetic relationships among 26 accessions of the genus Rosa L. from the gene pool collection of Nikita Botanical Gardens. They included 18 cultivated varieties and 8 accessions of wild species. The species sample included representatives of two subgenera, Rosa and Platyrhodon. The subgenus Platyrhodon was represented by one accession of the species R. roxburghii Tratt. Cultivated roses were represented by varieties of garden groups hybrid tea, floribunda, and grandiflora. The tested markers included 32 ISSRs and 13 IRAPs. Five ISSR markers (UBC 824, ASSR29, 3A21, UBC 864, and UBC 843) and three IRAPs (TDK 2R, Сass1, and Сass2) were chosen as the most promising. They were used for genotyping the studied sample of genotypes. In general, they appeared to be suitable for further use in studying the genetic diversity of the genus Rosa L. The numbers of polymorphic fragments ranged from 12 to 31, averaging 19.25 fragments per marker. For markers UBC 864 and UBC 843, unique fingerprints were identified in each accession studied. The genetic relationships of the studied species and varieties of roses analyzed by the UPGMA, PCoA, and Bayesian methods performed on the basis of IRAP and ISSR genotyping are consistent with their taxonomic positions. The genotype of the species R. roxburghii of the subgenus Platyrhodon was determined genetically as the most distant. According to clustering methods, the representative of the species R. bengalensis did not stand out from the group of cultivated varieties. When assessing the level of genetic similarity among the cultivated varieties of garden roses, the most genetically isolated varieties were ‘Flamingo’, ‘Queen Elizabeth’, and ‘Kordes Sondermeldung’; for most of the other varieties, groups of the greatest genetic similarity were identified. This assessment reflects general trends in phylogenetic relationships, both among the studied species of the genus and among cultivated varieties

The method of determining the forces in the tendon apparatus of human fingers

Being one of the most functionally loaded systems, the human hand and its anatomical structures are damaged quite often. Thus, injuries to the interphalangeal joints account for up to 60 % of all hand injuries. Post-traumatic arthrosis, contractures with persistent pain syndrome, stiffness and ankylosis of the joints are distinguished among the consequences of hand joint injuries. With the development of the endoprosthesis method, the use of which allows to restore the lost function of the organs of the musculoskeletal system, new opportunities are opening up in the rehabilitation of patients with various injuries of the joints of the hand. However, when using this method, there are certain complications associated with the wear of the implant, the reaction of the surrounding tissues to the material from which the prosthesis is made, and the design features of endoprostheses. That is, the success of treatment when using endoprostheses depends to some extent on the design of the implant. It is possible to carry out a primary analysis of the effectiveness of the proposed design of the endoprosthesis with the help of specialized software complexes. Despite the power of specialized software, building digital models of biological objects and performing calculations is quite a difficult task. In order to carry out a numerical study, in addition to knowing of the geometry of objects and their mechanical properties, it is also necessary to understand the conditions of interaction between the model fragments and the loading scheme. Aim. Develop a technique for analytical determination of forces in the tendons of the fingers. Materials and methods. The research was carried out using the provisions and methods of theoretical mechanics and resistance of materials. As a calculation case, this paper proposes to consider the determination of forces in the tendons of the index finger of the right upper limb. Results. As a result of the performed calculations, analytical expressions were obtained to determine the forces that occur in the flexor tendons of the index finger. Conclusions. The obtained analytical expressions allow us to estimate the magnitude of forces that occur in the tendons of the fingers. The results of the calculations can be used in the construction of digital models of the fingers and perform numerical studies

Expression of palmitoyl transferases in brain structures of mice genetically predisposed to depressive-like behavior

Most G-coupled receptors undergo posttranslational modifications. Among these modifications is S-palmitoylation, carried out by specialized enzymes palmitoyl transferases. Palmitoylation is the covalent attachment of a long-chain fatty acid, palmitate, to cysteine residues. It can influence receptor stability, transportation, and function. Obviously, malfunction of G-protein coupled receptors can cause various psychic disor­ders, including depression. However, no association between palmitoyl transferases and depressive-like behavior has been found hitherto. There is no informa­tion on brain structure specific features of palmitoyl transferase expression either. Here we investigate the expression of ZDHHC5, ZDHHC9, and ZDHHC21 palmi­toyl transferases in brain structures of ASC mice with genetic predisposition to depressive-like behavior in comparison with “nondepressive” CBA mice. Several brain region-specific features were detected in the immunodetection of palmitoyl transferase proteins. Western blot of the ZDHHC5 protein in the midbrain revealed two bands at 75 kDa and 55 kDa. Immuno­detection of ZDHHC21 palmitoyl transferase revealed two bands. One of them was visualized at 27 kDa in the frontal cortex and midbrain. The other, at 32 kDa in the hippocampus. Probing for ZDHHC9 also showed two bands in each of the midbrain and hippocampus, at 46 and 41 kDa. However, the expression of all investigated palmitoyl transferases in ASC mice with depressive-like behavior was almost identical to those in CBA mice. Thus, it was the first detection of brain region-specific features of the expression of investigated palmitoyl transferases. However, the study demonstrates that the genetic predisposition to depression-like behavior in ASC mice is not associated with changes in ZDHHC5, ZDHHC9, or ZDHHC21 palmitoyl transferase expression

Surface impedance anisotropy of YBa2_2Cu3_3O6.95_{6.95} single crystals: electrodynamic basis of the measurements

An electrodynamic technique is developed for determining the components of surface impedance and complex conductivity tensors of HTSC single crystals on the basis of measured quantities of a quality factor and a resonator frequency shift. A simple formula is obtained for a geometrical factor of a crystal in the form of a plate with dimensions $b\gg a>c$ in a microwave magnetic field ${\bf H_{\omega}}\perp ab$. To obtain the c-axis complex conductivity from measurements at ${\bf H_{\omega}}\parallel ab$ we propose a procedure which takes account of sample size effects. With the aid of the technique involved temperature dependences of all impedance and conductivity tensors components of YBa$_2$Cu$_3$O$_{6.95}$ single crystal, grown in BaZrO$_3$ crucible, are determined at a frequency of $f=9.4$ GHz in its normal and superconducting states. All of them proved to be linear at $T<T_c/2$, and their extrapolation to zero temperature gives the values of residual surface resistance $R_{ab}(0)\approx 40$ $\mu\Omega$ and $R_c(0)\approx 0.8$ m$\Omega$ and magnetic field penetration depth $\lambda_{ab}(0)\approx 150$ nm and $\lambda_c(0)\approx 1.55$ $\mu$m.Comment: 9 pages, 7 figures. Submitted to Phys.Rev.B 05Jun2002; accepted for publication 21Febr200

Recommended Isolated-Line Profile for Representing High-Resolution Spectroscopic Transitions (IUPAC Technical Report)

The report of an IUPAC Task Group, formed in 2011 on Intensities and line shapes in high-resolution spectra of water isotopologues from experiment and theory (Project No. 2011-022-2-100), on line profiles of isolated high-resolution rotational-vibrational transitions perturbed by neutral gas-phase molecules is presented. The well-documented inadequacies of the Voigt profile (VP), used almost universally by databases and radiative-transfer codes, to represent pressure effects and Doppler broadening in isolated vibrational-rotational and pure rotational transitions of the water molecule have resulted in the development of a variety alternative line-profile models. These models capture more of the physics of the influence of pressure on line shapes but, in general, at the price of greater complexity. The Task Group recommends that the partially Correlated quadratic-Speed-Dependent Hard-Collision profile (pCqSD-HCP) should be adopted as the appropriate model for high-resolution spectroscopy. For simplicity this should be called the Hartmann-Tran profile (HTP). The HTP is sophisticated enough to capture the various collisional contributions to the isolated line shape, can be computed in a straightforward and rapid manner, and reduces to simpler profiles, including the Voigt profile, under certain simplifying assumptions. © 2014 IUPAC & De Gruyte

Field-induced structural evolution in the spin-Peierls compound CuGeO3_3: high-field ESR study

The dimerized-incommensurate phase transition in the spin-Peierls compound CuGeO$_3$ is probed using multifrequency high-resolution electron spin resonance (ESR) technique, in magnetic fields up to 17 T. A field-induced development of the soliton-like incommensurate superstructure is clearly indicated as a pronounced increase of the ESR linewidth $\Delta B$ (magnon excitations), with a $\Delta B_{max}$ at $B_{c}\sim$ 13.8 T. The anomaly is explained in terms of the magnon-soliton scattering, and suggests that the soliton-like phase exists close to the boundary of the dimerized-incommensurate phase transition. In addition, magnetic excitation spectra in 0.8% Si-doped CuGeO$_3$ are studied. Suppression of the $\Delta B$ anomaly observed in the doped samples suggests a collapse of the long-range-ordered soliton states upon doping, that is consistent with high-field neutron scattering experiments.Comment: Accepted to Phys. Rev.

MICROSATELLITES-BASED EVALUATION OF THE PEAR CULTIVARS SELECTED FROM NIKITSKY BOTANICAL GARDENS GERMPLASM BY THEIR ECONOMICALLY VALUABLE CHARACTERISTICS

Mobilization and preservation of genetic sources of diversity of the cultivated pear varieties and their wild relatives is one of the main aspects of new cultivars breeding for modern intensive horticulture. The crucial matter during a new cultivar creation goes to the selection of parental pairs, which obtain a complex of positive features. The aim of this work is to study the Gene Fund collection of pear plantings from Nikitsky Botanical Gardens in accordance with the main economically important traits and to select the most valuable genotypes for using them in breeding programs as a starting material, as well as to conduct a DNA-fingerprinting and the analyses of genetic polymorphism of promising cultivars from the collection of pear with implementing of microsatellite analyses. As a result of long-term studies the following cultivars were selected in accordance with the complex of features promising for the breeding program: Gvardeiskaya Zimnyaya, Izuminka Kryma, Izumrudnaya, Kelmenchanka, Krymskaya Aromatnaya, Krymskaya Medovaya, Lazurnaya, Maria, Mriya, Nadezhda Stepi, Nezabudka, Novosadovskaya, Oreanda Kryma, Otechestvennaya, Tauschaya, Yakimovskaya. The samples of these cultivars were forwarded for genotyping. For the genetic polymorphism analyses of the studied cultivars, seven microsatellite DNA-markers – EMPc108, EMPc117, EMPc115, CH04e03 and CH01d09, CH01f07a, CH01d08 – grouped into 2 multiplex sets were used. The SSR-markers were significantly different according to their level of polymorphism – from 3 (CH04e03 marker) to 11 (EMPc115) alleles per a gene locus were revealed, the effective number of alleles varying from 1.37 to 4.65. Based on SSR-markers polymorphism analysis data, the rate of genetic similarity of the studied pear cultivars was estimated. This evaluation research helped estimate genetic relations inside the studied sample collection of genotypes. The SSR-fingerprints of the cultivars obtained will be used as a starting material for the creation of DNA-passports database of the “NBG – NSC” Gene Fund collection of pear cultivars

Recommended isolated-line profile for representing high-resolution spectroscopic transitions (IUPAC Technical Report)

The report of an IUPAC Task Group, formed in 2011 on "Intensities and line shapes in high-resolution spectra of water isotopologues from experiment and theory" (Project No. 2011-022-2-100), on line profiles of isolated high-resolution rotational-vibrational transitions perturbed by neutral gas-phase molecules is presented. The well-documented inadequacies of the Voigt profile (VP), used almost universally by databases and radiative-transfer codes, to represent pressure effects and Doppler broadening in isolated vibrational-rotational and pure rotational transitions of the water molecule have resulted in the development of a variety of alternative line-profile models. These models capture more of the physics of the influence of pressure on line shapes but, in general, at the price of greater complexity. The Task Group recommends that the partially Correlated quadratic-Speed-Dependent Hard-Collision profile should be adopted as the appropriate model for high-resolution spectroscopy. For simplicity this should be called the Hartmann--Tran profile (HTP). The HTP is sophisticated enough to capture the various collisional contributions to the isolated line shape, can be computed in a straightforward and rapid manner, and reduces to simpler profiles, including the Voigt profile, under certain simplifying assumptions.Comment: Accepted for publication in Pure and Applied Chemistr