X-ray transition radiation detectors (TRDs) are used for particle identification in both high energy physics and astroparticle physics. In most of the detectors, emission of the X-ray transition ...radiation (TR) starts at Lorentz factors above γ∼500 and reaches saturation at γ∼2÷3⋅103. However, many experiments require particle identification up to γ∼105, which is very difficult to achieve with conventional detectors. Semiconductor pixel detectors offer a unique opportunity for precise simultaneous measurements of spectral and angular parameters of TR photons. Test beam studies of the energy and the angular distributions of TR photons emitted by electrons and muons of different momenta crossing several types of radiators were performed at the CERN SPS with a 480 μm thick silicon detector bonded to a Timepix3 chip. High resolution images of the energy−angle phase space of the TR produced by different radiators were obtained and compared with MC simulations. The characteristic interference patterns are in agreement with the theoretical models with an unprecedented level of details. The studies presented in this paper also show that simultaneous measurements of both the energy and the emission angles of the TR X-rays could be used to enhance the particle identification performances of TRDs.
The release kinetics of afobazole from a new solid dosage form of prolonged-release film-coated tablets was studied
in vitro
. The conditions of the dissolution test were experimentally determined ...with the use of the basket apparatus type I and phosphate buffer solution pH 6.8 (Eur. Ph.) as the dissolution medium. The specification release limits were ≤25% after 1 h, 45 – 60% after 6 h, and ≥80% after 24 h of the nominal afobazole content in the tablets. The release kinetics of afobazole from the prolonged-release tablets were evaluated using the first-order, Higuchi, and Korsmeyer(Peppas mathematical models. The release mechanism of the active ingredient from the matrix could be characterized as anomalous diffusion according to the Korsmeyer(Pappas model.
We have hypothesized that the adaptive response to low doses of ionizing radiation (IR) is mediated by oxidized cell-free DNA (cfDNA) fragments. Here, we summarize our experimental evidence for this ...model. Studies involving measurements of ROS, expression of the NOX (superoxide radical production), induction of apoptosis and DNA double-strand breaks, antiapoptotic gene expression and cell cycle inhibition confirm this hypothesis. We have demonstrated that treatment of mesenchymal stem cells (MSCs) with low doses of IR (10 cGy) leads to cell death of part of cell population and release of oxidized cfDNA. cfDNA has the ability to penetrate into the cytoplasm of other cells. Oxidized cfDNA, like low doses of IR, induces oxidative stress, ROS production, ROS-induced oxidative modifications of nuclear DNA, DNA breaks, arrest of the cell cycle, activation of DNA reparation and antioxidant response, and inhibition of apoptosis. The MSCs pretreated with low dose of irradiation or oxidized cfDNA were equally effective in induction of adaptive response to challenge further dose of radiation. Our studies suggest that oxidized cfDNA is a signaling molecule in the stress signaling that mediates radiation-induced bystander effects and that it is an important component of the development of radioadaptive responses to low doses of IR.
Aim.
To study the changes of the major risk factors (RFs) and vascular status in students over six years of their education at a medical university.
Material and methods
. A total of 667 students ...aged 17,8±1,2 years were examined in the 1st year and 6th year (162 men, 505 women). Students who entered in the same year were combined into one cohort, while in total 5 cohorts were recruited. The screening examination was carried out as part of the annual intra-university events "Freshman Week", "Graduate Week" by staff of the University Health Center and included the collection of complaints and history, height, body weight, the measurement of peripheral and central blood pressure, as well as the assessment vascular stiffness and metabolic status. Statistical analysis of the material was carried out using SPSS Statistics 23.0.
Results.
Analysis of RFs in medical students over 6 years showed a significant increase of the prevalence of hypertension/prehypertension, resting tachycardia, obesity/overweight, malnutrition and physical inactivity. An assessment of central and peripheral hemodynamics, as well as vascular stiffness of students, revealed an increase in the level of aortic systolic pressure, combined with an increase in peripheral systolic blood pressure and pulse. At the same time, there was no significant increase in some parameters of vascular stiffness, against the background of a 2-fold increase in the prevalence of overweight. Analysis of the metabolic status reveals a significant change in total cholesterol and triglycerides but no alterations in capillary blood glucose.
Conclusion.
The data obtained indicate an increase in the prevalence of not only behavioral, but also biological RFs among medical students, as well as the development of preclinical vascular remodeling in them during a six-year education, which can later lead to early cardiovascular diseases. Therefore, widespread screening system of risk factors among students should be developed.
Some time ago, potato transformants expressing Agrobacterium-derived auxin synthesis gene tms1 were generated. These tms1-transgenic plants, showing enhanced productivity, were studied for their ...hormonal status, turnover and responses in comparison with control plants. For this purpose, contents of phytohormones belonging to six different classes (auxins, cytokinins, gibberellins, abscisic, jasmonic and salicylic acids) were determined by a sensitive UPLC-MS/MS method in tubers and shoots of in vitro grown plants. To date, this study represents the most comprehensive analysis of the potato hormonal system. On the basis of obtained results, several new generalizations concerning potato hormonal status were drawn. Overall, these data can serve as a framework for forthcoming integrative studies of the hormonal system in potato plants.
Starch metabolism in potato Solanum tuberosum L Sergeeva, E. M.; Larichev, K. T.; Salina, E. A. ...
Vavilovskiĭ zhurnal genetiki i selekt͡s︡ii,
06/2022, Letnik:
26, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Starch is a major storage carbohydrate in plants. It is an important source of calories in the human and animal diet. Also, it is widely used in various industries. Native starch consists of ...water-insoluble semicrystalline granules formed by natural glucose polymers amylose and amylopectin. The physicochemical properties of starch are determined by the amylose:amylopectin ratio in the granule and degrees of their polymerization and phosphorylation. Potato
Solanum tuberosum
L. is one of the main starch-producing crops. Growing industrial needs necessitate the breeding of plant varieties with increased starch content and specified starch properties. This task demands detailed information on starch metabolism in the producing plant. It is a complex process, requiring the orchestrated work of many enzymes, transporter and targeting proteins, transcription factors, and other regulators. Two types of starch are recognized with regard to their biological functions. Transitory starch is synthesized in chloroplasts of photosynthetic organs and degraded in the absence of light, providing carbohydrates for cell needs. Storage starch is synthesized and stored in amyloplasts of storage organs: grains and tubers. The main enzymatic reactions of starch biosynthesis and degradation, as well as carbohydrate transport and metabolism, are well known in the case of transitory starch of the model plant
Arabidopsis thaliana
. Less is known about features of starch metabolism in storage organs, in particular, potato tubers. Several issues remain obscure: the roles of enzyme isoforms and different regulatory factors in tissues at various plant developmental stages and under different environmental conditions; alternative enzymatic processes; targeting and transport proteins. In this review, the key enzymatic reactions of plant carbohydrate metabolism, transitory and storage starch biosynthesis, and starch degradation are discussed, and features specific for potato are outlined. Attention is also paid to the known regulatory factors affecting starch metabolism.
Growing energies of particles at modern or planned particle accelerator experiments as well as cosmic ray experiments require particle identification at gamma-factors (γ) of up to ∼105. At present ...there are no detectors capable of identifying charged particles with reliable efficiency in this range of γ. New developments in high granular pixel detectors allow one to perform simultaneous measurements of the energies and the emission angles of generated transition radiation (TR) X-rays and use the maximum available information to identify particles. First results of studies of TR energy-angular distributions using gallium arsenide (GaAs) sensors bonded to Timepix3 chips are presented. The results are compared with those obtained using a silicon (Si) sensor of the same thickness of 500 μm. The analysis techniques used for these experiments are discussed.
X-ray Transition radiation detectors (TRDs) are used for particle identification in both high energy physics and astroparticle physics. Particle identification is often achieved based on a threshold ...effect of the X-ray transition radiation (TR). In most of the detectors, TR emission starts at γ factors above ∼500 and reaches saturation at γ∼2−3⋅103. However, many experiments require particle identification up to γ∼105, which is difficult to achieve with current detectors, based only on the measurement of the photon energy together with the particle ionization losses. Additional information on the Lorentz factor can be extracted from the angular distribution of TR photons. TRDs based on pixel detectors give a unique opportunity for precise measurements of spectral and angular distributions of TR at the same time. A 500 μm thick silicon sensor bump bonded to a Timepix3 chip was used in a test beam measurement at the CERN SPS. A beam telescope was employed to separate clusters produced by the primary beam particles from the potential TR clusters. Spectral and angular distributions of TR were studied with high precision for the first time using beams of pions, electrons and muons at different momenta. In this paper, the measurement and analysis techniques are described, and first results are presented.
A method for determination of related impurities in the new anxiolytic drug substance GML-3 was developed. HPLC and TLC techniques that could identify starting materials and synthetic intermediates ...and quantify them and unidentified impurities with contents of 0.05% and less in the drug substance were developed. The proposed techniques could be used further for quality control of GML-3 drug substance.
Anovel gas-chromatographic method with static headspace extraction was developed and validated for identifying and determining quantitatively residual organic solvents in the drug substance of an ...innovative dipeptide mimetic of nerve growth factor (GK-2). The developed chromatography conditions allowed effective separation of the chromatographic peaks for all organic solvents used to synthesize and purify the drug substance, i.e., MeOH, toluene, CH
2
Cl
2
, Py, EtOH, Et
2
O, and trifluoroacetic acid. Validation of the method confirmed its specificity, linearity, accuracy, and precision.
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