The problem of determining biologically active low-molecular-weight aminothiols, such as cysteine and glutathione, requires the development of new methods and analytical reagents. Among the latter ...substances, a group of spiropyrans can be distinguished, which are photochromic organic substances reaching an equilibrium between their cyclic and open forms in solutions. We consider a possibility of using benzofuran spiropyrans as analytical reagents for aminothiols and studied the effect of various substituents in their structure on the change in optical properties in the presence of cysteine and glutathione. An equilibrium in solutions of benzofuran spiropyrans bearing a hydroxyl group in position 7 shifts in the presence of analytes towards the formation of a colored open form. The considered spiropyrans were used to create a simple, selective, and sensitive procedure for the spectrophotometric and kinetic determination of cysteine and glutathione in vitro.
Throughout history, humans have been attempting to develop the ornamental features of domestic animals in addition to their productive qualities. Many chicken breeds have developed tufts of elongated ...feathers that jut out from the sides and bottom of the beak, leading to the phenotype known as muffs and beard. It is an incomplete autosomal dominant phenotype determined by the Mb locus localised on chromosome GGA27. This project aimed to analyse the genetic diversity of chicken breeds using full genomic genotyping with the Chicken 60K BeadChip. A total of 53,313 Single Nucleotide Polymorphisms were analysed. DNA was obtained from breeds with the muffs and beard as a marker phenotype: Faverolles (n = 20), Ukrainian Muffed (n = 18), Orloff (n = 20), Novopavlov White (n = 20), and Novopavlov Coloured (n = 15). The Russian White (n = 20) was selected as an alternative breed without the muffs and beard phenotype. The chickens are owned by the Centre of Collective Use "Genetic Collection of Rare and Endangered Breeds of Chickens" (St. Petersburg region, Pushkin), and are also included in the Core Shared Research Facility (CSRF) and/or Large-Scale Research Facility (LSRF). Multidimensional scaling revealed that the Novopavlov White and the Novopavlov Coloured populations formed a separate group. The Ukrainian Muffed and the Orloff have also been combined into a separate group. Based on cluster analysis, with the cross-validation error and the most probable number of clusters K = 4 taken into account, the Orloff was singled out as a separate group. The Ukrainian Muffed exhibited a notable similarity with the Orloff under the same conditions. At K = 5, the populations of the Novopavlov White and the Novopavlov Coloured diverged. Only at K = 6, a distinct and separate cluster was formed by the Ukrainian Muffed. The Russian White had the greatest number of short (1-2 Mb) homozygous regions. If the HOXB8 gene is located between 3.402 and 3.404 Mb on chromosome GGA27, homozygous regions are rarely found in the chickens with the muffs and beard phenotype. Scanning the chicken genome with the Chicken 60K BeadChip provided enough information about the genetic diversity of the chicken breeds for the peculiarities of the development of the ornamental muffs and beard phenotypes in them to be understood. For example, Phoenix bantams, whose tail feathers grow throughout their lives, require greater consideration of husbandry conditions.
The cross section for the neutron-induced fission of
238
U nuclei has been measured using the time-of-flight spectrometer of the GNEIS neutron complex at the Petersburg Nuclear Physics Institute, ...National Research Center Kurchatov Institute, in the neutron energy range of 0.3–500 MeV. Fission fragments have been detected by low-pressure position-sensitive multiwire proportional counters. The cross section for
238
U(
n
,
f
) fission has been measured with respect to the cross section for
235
U(
n
,
f
) fission, which is an accepted international standard. Data on the energy dependence of the anisotropy of the angular distribution of fragments of neutron-induced
238
U nuclei are also presented. The data obtained have been compared to previous experiments carried out using both similar and significantly different methods.
Using the Geant4 software package, a numerical simulation of a neutron source of the time-offlight spectrometer GNEIS created on the basis of the SC-1000 synchrocyclotron with 1 GeV proton energy at ...the NRC Kurchatov Institute—PNPI (Gatchina) has been carried out. The influence of the structural features of the neutron source of the spectrometer on the spatial and energy distributions of neutrons has been studied. The intensity and spectral characteristics of the neutron flux in the range of 1–1000 MeV have been determined on the basis of the obtained information and detailed allowance for all elements of the neutron beam guide system. It is found that the best agreement between the experiment and calculation performed by means of Geant4 is observed when using the QGSP_INCLXX_HP model. In the neutron energy range of 1–200 MeV, the difference between the experimental and calculated shapes of the spectra is less than 25%.
The article presents the investigation of the influence of tree and shrub vegetation on the discharge capacity of a river bed during high water. It was traced, that the calculating methods for ...roughness code and floodplain throughput capacity are good enough in case of a simple form of a river lengthwise section, but they do not work in case of meandering channels and in case of overgrown floodplain with vegetation: calculating errors significantly exceed the permissible ones. The method for eliminating the adverse effects of vegetation is proposed. The studies use the field observations results of the processes of vegetation influence on erosion effect and the sediment deposits. The field of observation is located in the middle part of the Volga-Akhtubinskaya floodplain (Kharabalinsky district). Space images (Yandex maps, Sputnik) of this area are used to improve the results of investigation. To correct the calculations in each specific case, it is necessary to carry out additional field hydrological studies. These studies will undoubtedly be much cheaper than the reconstruction costs of the hydraulic systems, and the costs of eliminating the accident results. Based on the research results, a simple and low-cost method for eliminating the impact of vegetation is proposed.
Sequential reaction of cyclohexanone with malononitrile and 2-aminopropene-1,1,3-tricarbonitrile in the presence of potassium hydroxide or sodium ethylate in ethanol gave ...4-imino-2-(dicyanomethylene)-3-azaspiro5.5undecane-1,5-dicarbonitrile. The latter reacted with primary amines and an excess of formaldehyde to form new 2-(dicyanomethylene)-3,7-diazaspirobicyclo3.3.1non-3-ene-9,1′-cyclohexane-1.5-dicarbonitrile derivatives. Contrary to the literature data, the reaction of cyclohexanone with 2-aminopropene-1,1,3-tricarbonitrile in benzene in the presence of piperidine and glacial acetic acid led to the formation of 2,4-diamino-5,6,7,8-tetrahydronaphthalene-1,3-dicarbonitrile.
Possible isomers of the N-(3,4-dimethylphenyl)-2-(7-hydroxy-3′,3′-dimethyl-3′H-spirochromene-2,1′-isobenzofuran-8-yl)methylidinehydrazinocarbothioamide (
HL
) spiropyran of the 2-oxaindane series and ...the
M
L(H
2
O)
3
+
(
M
= Mn(II), Fe(II), Co(II)) complexes on its basis are calculated by the quantum chemical DFT (CAM-B3LYP/6-311++G(
d
,
p
)) method. It is shown that complexation inverts the relative stability of spiro- and acyclic isomers of
L
; the acyclic isomer of the ligand is the most stable one among all the complexes for all metals. The effect of ligand structural isomerism on the relative stability of high- and low-spin states of coordination compounds is estimated.
We report on the results of theoretical and experimental studies of photoluminescense of silicon nanocrystals in the proximity to plasmonic modes of different types. In the studied samples, the type ...of plasmonic mode is determined by the filling ratio of a one-dimensional array of gold stripes which covers the thin film with silicon nanocrystals on a quartz substrate. We analyze the extinction, photoluminesce spectra and decay kinetics of silicon nanocrystals and show that the incident and emitted light is coupled to the corresponding plasmonic mode. We demonstrate the modification of the extinction and photoluminesce spectra under the transition from wide to narrow gold stripes. The experimental extinction and photoluminescense spectra are in good agreement with theoretical calculations performed by the rigorous coupled wave analysis. We study the contribution of individual silicon nanocrystals to the overall photoluminescense intensity, depending on their spacial position inside the structure.
Here, the energy spectrum of prompt neutron emitted in fission (PFNS) plays a very important role in nuclear science and technology. A Coordinated Research Project (CRP) "Evaluation of Prompt Fission ...Neutron Spectra of Actinides" was established by the IAEA Nuclear Data Section in 2009, with the major goal to produce new PFNS evaluations with uncertainties for actinide nuclei.
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