Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 34
Filter
1.
Rev Sci Instrum ; 95(1)2024 Jan 01.
Article in English | MEDLINE | ID: mdl-38180346

ABSTRACT

In this paper, we present the design and commissioning results of the upgraded collective Thomson scattering diagnostic at the Wendelstein 7-X stellarator. The diagnostic has a new radiometer designed to operate between the second and third harmonics of the electron cyclotron emission from the plasma at 171-177 GHz, where the emission background has a minimum and is of order 10-100 eV. It allows us to receive the scattered electromagnetic field with a significantly improved signal-to-noise ratio and extends the set of possible scattering geometries compared to the case of the original instrument operated at 140 GHz. The elements of the diagnostic are a narrowband notch filter and a frequency stabilized probing gyrotron that will allow measuring scattered radiation spectra very close to the probing frequency. Here, we characterize the microwave components applied to the radiometer and demonstrate the performance of the complete system that was achieved during the latest experimental campaign, OP2.1.

2.
Rev Sci Instrum ; 92(12): 124704, 2021 Dec 01.
Article in English | MEDLINE | ID: mdl-34972453

ABSTRACT

The results of the concept development of the universal high-voltage power supply with the output parameters providing the reliable operation of compact THz vacuum electron devices have been presented and discussed. The low-level of high-voltage ripples less than 10 ppm at 6 kV, 250 mA was obtained with the help of the designed high-precision and fast-response stabilization scheme. Real-time stabilization of the output parameters of vacuum electron devices was realized by using the multiloop proportional-integral-differential feedback control and was tested with the continuous-wave clinotron tubes in millimeter range. The developed high-voltage power supply offers the high-voltage modulation mode that allows applying the THz tubes with electronic frequency tuning for frequency-modulated continuous wave radar applications.

3.
Chem Commun (Camb) ; 53(5): 885-888, 2017 Jan 16.
Article in English | MEDLINE | ID: mdl-28004047

ABSTRACT

For the first time, the synthesis of organosilicon derivatives of dialkyl[1]benzothieno[3,2-b][1]-benzothiophene (BTBT) capable of forming a semiconducting monolayer at the water-air interface is reported. Self-assembled monolayer organic field-effect transistors prepared from these materials using the Langmuir-Blodgett technique showed high hole mobilities and excellent air stability.

4.
Faraday Discuss ; 174: 313-39, 2014.
Article in English | MEDLINE | ID: mdl-25277550

ABSTRACT

This contribution describes recent progress in the design, synthesis and properties of solution-processible star-shaped oligomers and their application in organic photovoltaics. Even though alternative chemistry has been used to design such oligomers, the most successful approach is based on a triphenylamine donor branching center, (oligo)thiophene conjugated spacers and dicyanovinyl acceptor groups. These are mainly amorphous low band-gap organic semiconductors, though crystalline or liquid crystalline ordering can sometimes be realized. It was shown that the solubility, thermal behavior and structure of such molecules in the bulk strongly depend on the presence and position of alkyl groups, as well as on their length. The photovoltaic properties of solution-processed molecules of this type are now approaching 5% which exceeds those of vacuum-sublimed devices. The design rules and future perspectives of this class of organic photovoltaic molecules are discussed.

5.
Opt Express ; 20(16): 17816-22, 2012 Jul 30.
Article in English | MEDLINE | ID: mdl-23038332

ABSTRACT

We theoretically describe several classes of ultrashort partially coherent pulses that maintain their shape on propagation in coherent linear absorbers near optical resonance.

6.
Tsitol Genet ; 46(6): 3-11, 2012.
Article in Ukrainian | MEDLINE | ID: mdl-23285744

ABSTRACT

Original method of small regulatory si/miRNA isolation from plant cells was elaborated. PCR amplification of fragment cDNA 8H07 nematode Heterodera schachtii gene was carried out. Using Northern-blot method hybridization of plant si/miRNA with cDNA fragment of conservative region 8H07 gene the presence of their high homology is found out. The amplified cDNA fragment of nematode 8H07 gene in future will be used for creation recombinant gene with complementary antisense dsRNA sequence for increasing resistance of rape plants to parasitic nematodes.


Subject(s)
Brassica rapa/genetics , Conserved Sequence , DNA, Helminth/genetics , Genes, Helminth , MicroRNAs/genetics , RNA, Plant/genetics , Sequence Homology, Nucleic Acid , Tylenchoidea/genetics , Animals , Blotting, Northern , Brassica rapa/drug effects , Brassica rapa/parasitology , DNA, Complementary/genetics , Electrophoresis, Polyacrylamide Gel , Host-Parasite Interactions/genetics , MicroRNAs/isolation & purification , Plant Growth Regulators/pharmacology , Polymerase Chain Reaction , RNA, Plant/isolation & purification
7.
Commun Agric Appl Biol Sci ; 77(4): 779-87, 2012.
Article in English | MEDLINE | ID: mdl-23885445

ABSTRACT

Sugar beet cyst nematode Heterodera schachtii Schmidt is an economically important plant parasite of sugar beet in Ukraine. The pest control options are limited. Sugar beet cyst nematode resistant varieties are not available on the market. Carbamate and organophosphate pesticides have been banned due to the high toxicity. The problem is aggravated by continuously increasing of oilseed rape (which is suitable host for H. schachtii) growing area due to biofuel demands. Several studies' results indicate that PGRs have role in management of plant parasitic nematodes but for sugar beet it is not studied well. We had an objective- studying of the role of four compositional PGRs created based of avermectin in suppression of sugar beet cyst nematode population on sugar beet and oilseed rape caused by enhancing of endogenous si/miRNA complementary to H. schachtii mRNA. Laboratory study was conducted in 2011 with using method DOT-blot hybridization si/miRNA with mRNA and by testing inhibitory activity in cell free system protein biosynthesis. That was shown that application of the PGRs enhances sugar beet and oilseeds rape plant immune-protective properties and resistance against plant-parasitic nematode Heterodera schochtii through enhancement of synthesis of small regulatory si/miRNA related (complementary) to an mRNA structure of the parasitic organisms. As a result, translation of mRNA of the nematode is blocked and causes the mortality of plant parasite juveniles.


Subject(s)
Beta vulgaris/immunology , Brassica napus/immunology , MicroRNAs/metabolism , Plant Growth Regulators/metabolism , RNA, Plant/metabolism , RNA, Small Interfering/metabolism , Tylenchoidea/drug effects , Animals , Beta vulgaris/parasitology , Brassica napus/parasitology , Pest Control , RNA, Helminth/metabolism , RNA, Messenger/metabolism , Tylenchoidea/physiology , Ukraine
8.
Zh Evol Biokhim Fiziol ; 43(5): 391-7, 2007.
Article in Russian | MEDLINE | ID: mdl-18038634

ABSTRACT

The ATP-synthase gamma-subunit (FoF1) belongs to the rotor part of this oligomeric complex. Catalytic hydrolysis of adenosine triphosphate (ATP) is accompanied by rotation of gamma-polypeptide inside the sphere formed by six subunits (alphabeta)3 of the enzyme. The gamma-subunit regulates ATPase and ATP-synthase activities of the FoF1. In the present work, evolutionary and reverse changes of this regulatory polypeptide and their effect on properties of the enzyme are studied. It is suggested that elongation of the gamma-subunit globular part had resulted from the atpC intragene duplication in the process of adaptive evolution. The evolved fragment participates in light regulation of the chloroplast ATP-synthase.


Subject(s)
Evolution, Molecular , Photosynthesis/physiology , Proton-Translocating ATPases , Amino Acid Sequence , Base Sequence , Catalysis , Chloroplast Proton-Translocating ATPases/chemistry , Chloroplast Proton-Translocating ATPases/genetics , Chloroplast Proton-Translocating ATPases/physiology , Escherichia coli/enzymology , Escherichia coli/genetics , Escherichia coli/physiology , Models, Molecular , Molecular Sequence Data , Protein Conformation , Protein Subunits , Proton-Translocating ATPases/chemistry , Proton-Translocating ATPases/genetics , Proton-Translocating ATPases/physiology , Spinacia oleracea/enzymology , Spinacia oleracea/genetics , Spinacia oleracea/physiology
9.
Biochemistry (Mosc) ; 71(9): 1006-12, 2006 Sep.
Article in English | MEDLINE | ID: mdl-17009955

ABSTRACT

The codon 5383-5385 (CCG) in the atpC gene of the unc operon of Escherichia coli cells was replaced with the sequence encoding peptide A of human insulin. The foreign protein fused to the middle part of the gamma-subunit of ATP synthase affects neither biosynthesis of the chimeric polypeptide nor the integration of the EF(0) x F(1) enzyme into the membranes of the E. coli cells. The inserted peptide A does not inhibit the process of oxidative phosphorylation. The ATPase activity of the mutant EF(0) x F(1) enzyme was equal to that of the wild-type enzyme and was regulated by modifiers in the similar way, suggesting that the space in the stalk area of F(0)/F(1) interaction is enough for the introduction of an additional oligopeptide without changing catalytic properties of the ATP synthase.


Subject(s)
Insulin/metabolism , Mitochondrial Proton-Translocating ATPases/metabolism , Amino Acid Sequence , Base Sequence , Escherichia coli/enzymology , Humans , Mitochondrial Proton-Translocating ATPases/genetics , Molecular Sequence Data , Recombinant Fusion Proteins/metabolism
10.
Phys Rev E Stat Nonlin Soft Matter Phys ; 70(1 Pt 2): 015603, 2004.
Article in English | MEDLINE | ID: mdl-15324122

ABSTRACT

We present a general theory of partially coherent optical solitons in slow-responding nonlinear media that takes into account intensity fluctuations of the light sources generating such solitons. If intensity fluctuations of the source are negligible, the theory reduces to the previously reported mean-field theory of partially coherent solitons. However, when such fluctuations are significant, our theory shows that the properties of partially coherent solitons in saturable nonlinear media can be qualitatively different from those predicted by the mean-field theory.

11.
Opt Lett ; 29(4): 394-6, 2004 Feb 15.
Article in English | MEDLINE | ID: mdl-14971764

ABSTRACT

We introduce a new definition of the energy spectrum of a nonstationary ensemble of pulses that reduces to the usual ones in the limit of statistically stationary ensembles of signals and of fully temporarily coherent ensembles.

12.
Izv Akad Nauk Ser Biol ; (4): 438-46, 2003.
Article in Russian | MEDLINE | ID: mdl-12942750

ABSTRACT

We studied seeds of 13 species of genus Bauhinia L. They can be divided into two groups considerably differing by the macro-, micro-, and ultrastructure. The obtained data should be used for the genus taxonomy.


Subject(s)
Bauhinia/anatomy & histology , Bauhinia/classification , Seeds/anatomy & histology , Species Specificity
13.
Phys Rev E Stat Nonlin Soft Matter Phys ; 64(3 Pt 2): 036618, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11580473

ABSTRACT

We show that a certain class of spatially partially coherent solitons, namely, twisted Gaussian Schell-model solitons, exists in a logarithmically saturable nonlinear medium with a noninstantaneous temporal response. Unlike previously reported Gaussian Schell-model solitons, those discussed here carry a position-dependent twist phase, which vanishes in the fully coherent limit. We demonstrate that the presence of the twist phase provides an opportunity for controlling the degree of spatial coherence of such solitons without affecting their intensity.

14.
J Opt Soc Am A Opt Image Sci Vis ; 18(1): 150-6, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11151992

ABSTRACT

A new class of partially coherent beams with a separable phase, which carry optical vortices, is introduced. It is shown that any member of the class can be represented as an incoherent superposition of fully coherent Laguerre-Gauss modes of arbitrary order, with the same azimuthal mode index. The free-space propagation properties of such partially coherent beams are studied analytically, and their M2 quality factor is investigated numerically.

15.
Opt Lett ; 26(3): 122-4, 2001 Feb 01.
Article in English | MEDLINE | ID: mdl-18033523

ABSTRACT

We study effective spatial and angular correlations in beams of any state of spatial coherence, and we introduce a phase-space product, Q , which takes these correlations into account. This phase-space product is shown to reduce to the conventional beam-quality factor M(2) when the beam is spatially fully coherent. We also determine the lower bound for the value of Q and demonstrate that it is attained for all Gaussian Schell-model beams.

16.
Cornea ; 19(4): 433-8, 2000 Jul.
Article in English | MEDLINE | ID: mdl-10928752

ABSTRACT

PURPOSE: To determine whether visual acuity (VA) measurements performed at low levels of contrast and glare are a better diagnostic tool for determining whether corneal clouding warrants surgery. METHODS: Fifty-nine subjects were recruited from among the candidates for corneal graft. Monocular VA was measured with three Regan contrast VA charts: 96, 25, and 11%, with and without glare provided by the Brightness Acuity Tester (BAT). The discriminative ability of the tests was estimated using the area (AR) under receiver operating characteristic (ROC) curves. Associations between the different VA tests and the Visual Function Index (VF-14) score were studied, using Spearman coefficients. RESULTS: When comparing candidate eyes with contralateral eyes with corneal disease, lower contrasts VA tests provided greater discriminative power. VA measurements made with glare also tended to provide greater discrimination. In fact, discrimination was best with 11% contrast VA with glare, but "testability" was poor. The most practical test in a clinical setting, which retained high discriminative ability (0.798), was the 25% contrast VA with glare. The eye with the best VA correlated strongly with the VF-14, especially at 25% contrast without glare, resulting in an Rs of -0.729. CONCLUSION: Twenty-five percent contrast VA with BAT could help the practitioner to decide whether a corneal transplant is warranted when symptoms of reduced vision are more important than what high-contrast VA might indicate.


Subject(s)
Contrast Sensitivity/physiology , Glare , Keratoplasty, Penetrating , Preoperative Care/methods , Vision Tests/methods , Adult , Aged , Aged, 80 and over , Discriminant Analysis , Female , Humans , Male , Middle Aged , Patient Selection , Prognosis , Reproducibility of Results , Retrospective Studies , Surveys and Questionnaires
17.
Mikrobiol Z ; 62(3): 36-42, 2000.
Article in Ukrainian | MEDLINE | ID: mdl-10932541

ABSTRACT

Biostimulants ivin and emistym take positive effect on the growth characteristics of natural association of soil microorganisms: they increase the specific growth rate, the number of generations, decrease the lag-phase and duration of redoubling the number of microorganisms. Presence of fungicides in the medium inhibits the growth of microorganisms. Under combined use of biostimulants and fungicides one cannot reveal the negative effect of fungicides on the natural associations of microorganisms, however the stimulating action of growth-regulating substances decreases.


Subject(s)
Dioxolanes/pharmacology , Fungicides, Industrial/pharmacology , Growth Substances/pharmacology , Soil Microbiology , Triazoles/pharmacology , Culture Media , Depression, Chemical , Dose-Response Relationship, Drug , Drug Combinations , Stimulation, Chemical
18.
Mikrobiol Z ; 62(5): 29-36, 2000.
Article in Ukrainian | MEDLINE | ID: mdl-11247341

ABSTRACT

Natural and synthetic biostimulants have been studied for their effect on resistance of soil microbe associations to pesticides. It has been shown that in the presence of growth-stimulating preparations (ivin, emistym, agrostimulin) in the microbial groups the number of microorganisms resistant to such fungicides as phenpiclonyl, fluodioxonyl, diphenoconasol increases. The activity of redox-systems which can initiate the oxidative destruction of pesticides increased in microbial associations under the simultaneous use of biostimulants and fungicides.


Subject(s)
Fungicides, Industrial/pharmacology , Growth Substances/pharmacology , Soil Microbiology , Depression, Chemical , Dose-Response Relationship, Drug , Drug Combinations , Stimulation, Chemical
19.
Opt Lett ; 25(9): 663-5, 2000 May 01.
Article in English | MEDLINE | ID: mdl-18064144

ABSTRACT

We derive a reciprocity inequality involving the product of the effective size of a statistically stationary, planar, secondary source of any state of coherence and of the angular spread of the far-zone intensity generated by the source. We show that of all possible such sources, the fully spatially coherent lowest-order Hermite-Gaussian laser mode has the smallest possible reciprocity product.

20.
FEBS Lett ; 443(2): 136-8, 1999 Jan 25.
Article in English | MEDLINE | ID: mdl-9989591

ABSTRACT

Thylakoid energization by light causes destabilization of CF0CF1 so that the peripheral CF1 sector is more readily detached from the membrane by intermediate concentrations of the chaotropic salt NaSCN. Here we have investigated the correlation between the proton gradient-induced change of CF0CF1 interaction and CF0CF1 activation. The results indicate a close relationship between the two phenomena. The effect is most probably due to reduction of the electrostatic interaction between the two subcomplexes CF0 and CF1 as a consequence of protonations in the interface region.


Subject(s)
Chloroplasts/enzymology , Proton-Translocating ATPases/metabolism , Darkness , Enzyme Activation , Light , Protons , Sulfhydryl Compounds/metabolism
SELECTION OF CITATIONS
SEARCH DETAIL
...