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We study the sources of intense ultra-high-frequency (UHF) radiation (in the frequency range 1-6 GHz) arising during the development of high-voltage atmospheric discharges. The discharges were initiated in a long discharge gap by applying an approximately 1-MV pulse with positive or negative polarity. By employing a radio registration system based on ultrawideband antennas, we managed to localize the UHF radiation sources in the discharge with centimeter accuracy and investigate their temporal and spatial correlation with the discharge structures. The vast majority of the localized sources turned out to be concentrated in the near-electrode regions. It is found that the generation mechanism of intense UHF radiation in a laboratory discharge cannot be unambiguously associated with such basic processes as the head-on collision of opposite-polarity streamers or the interaction of single streamers with the near-electrode plasma at the surface of metal electrodes. We discovered that the observed UHF emission appears basically as a precursor of the intense plasma development in a certain discharge region, whereinto a bright counterstreamer comes a bit later. The findings were confirmed by the statistical observations and results of imaging the dynamics of the discharge structures with a nanosecond temporal resolution.

We provide comprehensive data on the spectral and temporal characteristics of low-frequency (LF) (MHz) and high-frequency (HF) (GHz) radio emissions and investigate their correlation with the streamer formation. We show that the propagation of streamers from the cathode is accompanied only by the LF radio emission (10-150 MHz). In contrast, the HF radio emission (1-4 GHz) arises during the travel of counterstreamers from the anode, which is also indicated by radio interferometric measurements. The power of the LF radio emission sharply increases almost synchronously with that of the HF radio emission. We find that the HF radio emission has a complex spectral and temporal structure and appears as multiple short (less than 1 ns) bursts characterized by various frequency components, existing in subnanosecond time intervals.

For a laboratory discharge initiated in a long air gap by a microsecond megavolt pulse, we simultaneously register wideband high-frequency microwave and hard-x-ray emissions and thoroughly analyze the temporal relationship of the emissions depending on the discharge evolution. The temporal structure of microwave radiation is found to consist of numerous short intense bursts with high-frequency components. We directly show that x-ray and microwave emissions can appear almost synchronously in the discharge but only when a complex net of countless plasma channels forms and spans the entire discharge gap. The channel formation is closely related to the intense development of multiple streamers.

Decasubstituted pillar[5]arenes containing amidopyridine fragments have been synthesized for the first time. As was shown by UV-vis spectroscopy, the pillar[5]arenes with p -amidopyridine fragments form supramolecular associates with Cu(II) and Pd(II) cations in methanol in a 2:1 ratio. Using a sol-gel approach these associates are transformed into metallo-supramolecular coordination polymers (supramolecular gels) which were characterized as amorphous powders by scanning electron microscopy (SEM) and dynamic light scattering (DLS). The powders are able to selectively adsorb up to 46% of nitrophenols from water and were incorporated into an electrochemical sensor to selectively recognize them in aqueous acidic solution.

The unusual temperature behavior of the electron spin resonance (ESR) spectra and magnetic properties are experimentally observed in copper(II) complexes with a dendritic ligand based on the Boltorn H30 polymer (Perstorp Specialty Chemicals AB, Sweden) functionalized with fumaric acid residues in a molar ratio of 1:6. The ESR spectra at low temperatures show signs of transition to higher spin states at temperatures below 8-10 K, and the temperature dependences of the integral ESR signal intensities and magnetic susceptibility show the positive deviation from the Curie-Weiss law, thereby pointing to the presence of ferromagnetic exchange interactions in the system under study. The values of the exchange interaction parameters are calculated by quantum-chemical simulation of the possible structure of the copper(II) complex when assuming the formation of trinuclear coordination sites embedded in the hyperbranched polymer structure. The results of density functional theory calculations indicate the possibility of ferromagnetic exchange through carboxylate bridges in the trinuclear magnetic clusters, and the calculated values of the exchange interaction parameters make it possible to construct theoretical curves of the temperature dependence of the effective magnetic moment, which satisfactorily fit the experimental data, especially considering that polymers are characterized by disperse molecular weights and chemical structures., Competing Interests: The authors declare no competing financial interest., (Copyright © 2019 American Chemical Society.)

Multi-junction solar cells with multiple p-n junctions made of different semiconductor materials have multiple bandgaps that allow reducing the relaxation energy loss and substantially increase the power-conversion efficiency. The choice of materials for each sub-cell is very limited due to the difficulties in extracting the current between the layers caused by the requirements for lattice- and current-matching. We propose a new vacuum multi-junction solar cell with multiple p-n junctions separated by vacuum gaps that allow using different semiconductor materials as cathode and anode, both activated to the state of effective negative electron affinity (NEA). In this work, the compact proximity focused vacuum tube with the GaAs(Cs,O) photocathode and AlGaAs/GaAs-(Cs,O) anode with GaAs quantum wells (QWs) is used as a prototype of a vacuum single-junction solar cell. The photodiode with the p-AlGaAs/GaAs anode showed the spectral power-conversion efficiency of about 1% at V bias  = 0 in transmission and reflection modes, while, at V bias  = 0.5 V, the efficiency increased up to 10%. In terms of energy conservation, we found the condition at which the energy cathode-to-anode transition was close to 1. Considering only the energy conservation part, the NEA-cell power-conversion efficiency can rich a quantum yield value which is measured up to more than 50%.

Potential clinical application of Bacillus pumulus cytotoxic ribonuclease (binase) selectively inducing the death of tumor cells makes it imperative to investigate its effect on the normal human microflora. Flow cytometry was used to determine that binase concentration causing the apoptosis of cancer cells had no effect of the viability of Escherichia coli K12. The changes in the paramagnetic centers of E. coli K12 cells in the presence of nontoxic binase concentrations revealed by EPR spectroscopy included higher EPR signals from iron-containing proteins (including those from the Fe-S clusters) and of the Mn(II) hyperfine structure. The TMTH spin probe (N-(1-hydroxy-2,2,6,6-tetramethylpiperidine-4-il)-2-methylpropanamide hydrochloride) was used to reveal a twofold increase in the levels of reactive oxygen species (ROS) in the cells, which induced oxidative stress in the enzyme-treated bacteria. Inductively coupled plasma mass spectrometry revealed elevated contents of alkaline (Li, Na, K), alkali earth (Mg, Ca), transition (Cr, Mn, Fe, Cu, Zn), and post-transition metals (Bi, Pb) in the cells. Elevated levels of Cu and Zn (which impair the activity of the respiratory chain enzymes) and of Mn, which is known as a superoxide dismutase cofactor, confirmed development of the oxidative stress in bacteria.

The study of the epidural space was performed on 362 samples of the vertebral column obtained from the fetuses aged from 16 weeks, newborns, children and adult persons aged up to 90 years, using anatomical and histological methods. Within the lateral parts of the epidural space, the lateral vaults were distinguished. A new anatomical interpretation of these structures is proposed, considering them as a complex of anatomical structures including the periosteum of the intervertebral foramen, the sleeve of dura mater, intervertebral veins, spinal arteries, adipose tissue, the system of the connective-tissue trabeculae, recurrent nerves controlling the blood flow in the vascular system of the vertebral channel and promoting the communication of the epidural space with the paravertebral areas.

The development of the epidural space was studied on 51 series of sections from embryos and early fetuses aged from four to 13 weeks using histological and embryological methods for plastic and graphic reconstruction. We found that three stages can be discriminated in the development of the epidural space: I) the primary epidural space (embryos of 16-31 mm crown-rump length (CRL); II) reduction of the primary epidural space (embryos of 35-55 mm CRL); and III) the secondary epidural space (embryos of 60-70 mm CRL and fetuses of 80-90 mm CRL). The morphogenesis of the primary epidural space is determined by the formative influence of the spinal cord and its dura mater, while that of the secondary epidural space is determined by the walls of the vertebral canal. In the spinal cord-dura mater of the spinal cord-vertebral canal correlation system, the latter two components, subjected to the inducing influence of the first, determine the morphogenesis of the epidural space via a system of morphogenetic correlations. The correlational relationships are apparent as time-linked connections between the rudiment of the dura mater of the spinal cord and the vertebral canal, resulting in the stage-by-stage formation of the epidural space in the ventrodorsal and craniocaudal directions. These same morphogenetic correlations also determine the staging of the development of the epidural space.

Variants in the structure of the upper margin of the epidural space at sites of transition from the dura mater of the spinal cord to the dura mater of the brain were studied. Stereoepidurographic (88 observations) and corrosion studies (49 observations) identified four levels for the position of the upper margin of the anterior section (intracranially located, lower edge of the occipital bone, bodies of C1 and C2) along with five levels for the posterior section (occipital bone, occipital bone-arch of C1, C1, C1-C2, C2) of the epidural space. Variants on the shape of the upper margin of the anterior (falciform, oval, and dentate in the frontal plane; pointed, flexed spurs, pointed slits, and olive-shaped in the sagittal plane) and posterior (collar-shaped, oval, and bidentate forks with prongs of equal length and forks with prongs of unequal lengths) sections of the epidural space arose as a result of asymmetry in the attachment of the upper sections of the sac of the dura mater of the spinal cord to the walls of the vertebral canal. Weak areas of the upper wall of the epidural space (sites of transition from the dura mater of the spinal cord to the dura mater of the brain, paravasal capsule of the vertebral artery, the area of the first intervertebral foramen) were seen.

A simple and efficient method for the preparation of 2-O-beta-D-ribofuranosylnucleosides, minor tRNA components, is described in this unit. The method consists of condensation of a small excess of 1-O-acetyl-2,3,5-tri-O-benzoyl-beta-D-ribofuranose activated with tin tetrachloride with N-protected 3,5-O-tetra-isopropyldisiloxane-1,3-diyl-ribonucleosides in 1,2-dichloroethane. Subsequent deprotection produces 2-O-beta-D-ribofuranosylnucleosides in an overall yield of 46% to 72%.

Variants of the structure of the superior limit of the epidural space at the sites of the spinal cord dura mater transition into cerebral dura matter were studied. Four levels of the superior limit position of the anterior (intracranial location, inferior limit of occipital bone, bodies of C(I) and C(II)) and five levels of the posterior sections (occipital bone, occipital bone-arch of C(I), C(II), C(I),-C(II), C(II)) of the epidural space were determined by the method of stereoepidurography (88 objects) and by corrosion (49 objects). Variants of the superior margin form of the anterior (in the frontal surface: falciform, oval and dentate forms and in the sagittal: pointed, flexured calcars, pointed slit and olive-shaped) and posterior portions (collar-shaped, oval, bidentate fork with equidimensional or unequidimensional teeth) of the epidural space caused by the asymmetry of fixation of the spinal cord dura matter to the walls of the spinal canal were described. Weak places of the superior wall in the epidural spaces (area of the spinal cord dura mater transition into the cerebral dura mater, paravasal capsule of the spinal artery, area of the first intervertebral foramen) were detected.

tRNA is best known for its function as amino acid carrier in the translation process, using the anticodon loop in the recognition process with mRNA. However, the impact of tRNA on cell function is much wider, and mutations in tRNA can lead to a broad range of diseases. Although the cloverleaf structure of tRNA is well-known based on X-ray-diffraction studies, little is known about the dynamics of this fold, the way structural dynamics of tRNA is influenced by the modified nucleotides present in tRNA, and their influence on the recognition of tRNA by synthetases, ribosomes, and other biomolecules. One of the reasons for this is the lack of good synthetic methods to incorporate modified nucleotides in tRNA so that larger amounts become available for NMR studies. Except of 2'-O-methylated nucleosides, only one other sugar-modified nucleoside is present in tRNA, i.e., 2'-O-beta-D-ribofuranosyl nucleosides. The T loop of tRNA often contains charged modified nucleosides, of which 1-methyladenosine and phosphorylated disaccharide nucleosides are striking examples. A protecting-group strategy was developed to introduce 1-methyladenosine and 5''-O-phosphorylated 2'-O-(beta-D-ribofuranosyl)-beta-D-ribofuranosyladenine in the same RNA fragment. The phosphorylation of the disaccharide nucleoside was performed after the assembly of the RNA on solid support. The modified RNA was characterized by mass-spectrometry analysis from the RNase T1 digestion fragments. The successful synthesis of this T loop of the tRNA of Schizosaccharomyces pombe initiator tRNA(Met) will be followed by its structural analysis by NMR and by studies on the influence of these modified nucleotides on dynamic interactions within the complete tRNA.

The formation of a disaccharide nucleoside (11) by O3'-glycosylation of 5'-O-protected 2'-deoxyadenosine or its N6-benzoylated derivative has been observed to be accompanied by anomerisation to the corresponding alpha-anomeric product (12). The latter reaction can be explained by instability of the N-glycosidic bond of purine 2'-deoxynucleosides in the presence of Lewis acids. An independent study on the anomerisation of partly blocked 2'-deoxyadenosine has been carried out. Additionally, transglycosylation has been utilized in the synthesis of 3'-O-beta-D-ribofuranosyl-2'deoxyadenosines and its alpha-anomer.

The synthesis of O-beta-D-ribofuranosyl-(1"-2')-adenosine-5"-O-phosphate and its suitably protected derivative for oligonucleotide synthesis have been developed.

The unexpected formation of trisaccharide nucleosides during synthesis of purine 5'-O-beta-D-ribofuranosylnucleosides in the presence of Lewis acids was observed.

Effect of nitrite ions on content of proteins (hemoglobin, albumin and others), peptides (AKTH and endothelin-1, 2) of total alpha-aminonitrogen and cGMP was studied in rat blood. The data obtained suggest that NO2- may be involved in regulation of these physiologically active substances because NO2- are the deposited form of nitric oxide which may regulate the inter- and intracellular signal systems.

Concentration of blood proteins, alpha-amino nitrogen, cGMP and endothelin-1,2 was studied in rat's blood at nitric hypoxia. The injection of NaNO2 (5 mg/100 g body weight) was followed by decrease in total protein, albumin and hemoglobin content and by sharp increase in methemoglobin and Hb-NO complexes concentration in rat's blood. Simultaneously, the elevation of free amino acids and peptides with m.w. 2500 D in blood was discovered. One of these peptides was the endothelin-1,2, whose concentration increased twice in plasma at nitric hypoxia. The increase in endothelin and cGMP concentrations is mostly linked with activation of compensative mechanisms, arising as a response to high concentrations of nitro compounds and NO in rats.

The results of studies are presented on the determination of aldosterone accumulation by mineralocorticoid receptors on cytoplasm and nuclei of normal rat renal tubules as well as in disturbed neurotrophic supply of the kidney including that against the background of activation and deprivation of the sympathetic nervous system function. It was shown that a pharmacological stimulation of sympathetic nervous system potentiated functional disturbances of the renal mineralocorticoid receptor apparatus in reflex dystrophy of the kidney. A simultaneous pharmacological blockade both of neural and of humoral transmission of pathological stimuli from damaged sciatic nerve to the kidney prevented the development of these disturbances. A belief is stated that there is a possibility of using adrenoceptor blockers as means to prevent or inhibit the development of dystrophic alterations in the organism which appear under the lesion of one or other part of the nervous system.

It has been established that the lesion of the sciatic nerve, accompanied by a disturbance of normal neurotrophic provision of a kidney as a result of coming to the organ of the perverted nervous stimuli (by the neuro-conductive path through sympathetic nerves and by participation of the hypothalamus--hypophysis--peripheral glands system), leads to disturbance of functioning of mineral-corticoid receptors of kidneys. It has been also established that simultaneous pharmacological blockade of neuro-conductive and humoral pathways of transmission to the kidney of pathological stimuli from the central stump of the cut sciatic nerve prevents the development of trophic organ disturbances, tested by the state of the kidney mineral-corticoid receptor apparatus, while pharmacological stimulation of sympathetic nervous system leads to the greater disturbance of aldosterone reception by the cells of kidney channels. A valid conclusion can be made that propranolol is a substance, which may weaken possible non-adequate reactions of peripheral tissues to the action of physiologically active substances during the development of the consequences of the lesion of the nervous system and thus to prevent the development of neurogenic dystrophies.

The results are presented of investigations on determining the functional state of mineralocorticoid receptor apparatus in rat kidney at diverse stages of the reflex renal dystrophy per se and that against the background of renal denervation along with propranolol injections produced at different terms following the disturbance of nervous system trophic function. It was shown that simultaneous blockade of neuroconductory and humoral pathways of pathological stimulus transmission from central end of cut ischiatic nerve to the kidney prevents the development of trophic disturbances in the organ as tested by the state of mineralocorticoid receptors, to a more extent than the blockade of neuroconductory pathway only. The activity of molecular structures which determine the mineralocorticoid reception in cells of renal tubules seems to be controlled both by central neuroconductory and humoral mechanisms.

Interaction of labeled aldosterone with rat kidney mineral corticoid cytoplasm receptors and duct cell nuclei at different dysfunctions of nervous-trophic organ supply. Dysfunction of vagus innervation leads to breakage of cytoplasm receptor apparatus and duct cell nuclei that performs aldosterone reception. Organ denervation and introduction of beta-adrenoblocking agent prevents development of kidney neurogenous dystrophy.

The spinal cord axial structures (AS) (its dura mater and vertebral canal) demonstrate the greatest growth rate during the intrauterine period and on the 18th month. After birth for the dura mater this age is 3 years, and for the spinal cord and the vertebral canal--7 years of age. The pubertal jump in growth of these formations is noted during the adolescent age (17-21 years). During the first two decades AS demonstrate asymptotic type of growth. In AS development the following periods in common have been revealed: a) intensive growth in children up to 7 years of age; b) growth stabilization (from 8 up to 16 years of age); c) period of a relative morphological stability (22-35 years); d) period of unstable compensatory-adaptive rearrangements (36-60 years); e) period of involutive changes (61-90 years).

The method is a follows: the cervical part of the vertebral column is mobilized from the inner cranial base with the preservation of the occipito-atlantic joint and with subsequent cranio-caudal extraction. This method does not disturb the epidural space and allows the extraction of the vertebral column without any assistance within 30 minutes.

A study was made of the effect of the compensatory hypertrophy of the rat kidney (on the 30th day) on the interaction of 3H-aldosterone with the receptors of the kidney cell tubules. It has been shown that the compensatory hypertrophy of the kidney is accompanied by an increased intensity of 3H-aldosterone binding with the receptors of the nephron cell cytoplasm and a decrease of the transfer of the hormonoreceptor cytoplasm and 3 receptor complex to the nucleus. These changes in the mechanism of aldosterone reception by the hypertrophic kidney can be accompanied by disturbed sensitivity of the organ to this mineralocorticoid.

The effect of reflex and denervated dystrophy of the rat kidneys on the interaction of aldosterone-3H with specific cytoplasmic receptors and nuclei of this organ was investigated in vitro and in vivo experiments. It was found that reflex dystrophy decreases the intensity of hormone binding with cytoplasmic receptors by 36% and aldosterone-3H accumulation in the renal nuclei by 51%. The influence of denervated dystrophy of the organ specific hormone accumulation in the same subcellular fractions was not observed. The more accurate data on the effect of renal reflex dystrophy on aldosterone-3H-receptor interaction were obtained in vivo experiments comparatively to those in vitro.

Dystrophy of rat kidney caused by denervation did not affect the binding of 3H-aldosterone with specific receptors of cytoplasm and nuclei in the small tubular cells. But under conditions of reflectory dystrophy the rates of 3H-aldosterone binding with cytoplasm receptors as well as the hormone transmission from cytoplasmic to nuclear receptors were decreased. The impairments observed in molecular mechanisms of the aldosterone consumption in kidney tubular cells may be responsible for alterations in the tissue sensitivity to the hormone, which was expressed primarily as deterioration of the Na+ reabsorption in the neurodystrophic injury.

Basing on our definition of the ES as a complex of peridural anatomical formations and taking into account certain peculiarities of their topographic distribution, 4 areas (anterior, posterior and two lateral) are defined. The posterior area of the ES by its sizes predominates over all the others. The ES value is determined by differences in rates of size increment of the vertebral canal and in rates of size increment of the spinal cord dura mater (SCDM). Position of the SCDM sac concerning the central axis of the canal predetermines++ the size of the ES four areas. The dimensions of the ES areas are not similar at various levels of the spinal column. For example, the dimensions of the ES posterior area in newborns are the greatest in the cervical part at CVII, in the thoracic--at ThIV-VII, in the lumbar--at LI-III, and the dimensions of the ES anterior area--at CVII, ThI-IV, LIV-V and Sr. The lateral ES areas are the widest at CI, ThIII, LV and SI. The greatest increase in the rate of increment of linear sizes and area is observed for the spinal canal and spinal cord in 5-, 8- and 9-month-old fetuses and for SCDM--in 5- and 8-month-old fetuses and for ES--in 6-, 8- and 9-month-old fetuses. The topographic peculiarities in the ES structure revealed and rearrangement of its dimensions in the fetuses and newborns can be useful in interpretation of problems on functional formation of the vertebral column, spinal cord and its tunics, and be of applied aspect at various manipulations performed in these formations in premature infants and in newborns.