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1.
Rev Sci Instrum ; 92(5): 055011, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-34243299

RESUMO

This paper presents main classes and varieties of sensors developed on the basis of the single-layer flat-coil-oscillator (SFCO) technology. The results of registration of human activity (steps and jumps) by seismic sensors based on this technology are presented and discussed in this paper. We applied some algorithms for digital processing of "RAW" data coming from vibrational seismic SFCO sensors, which made it possible to detect and mark out human steps and jumps from the background of natural ground vibrations. The unprecedented sensitivity of these sensors has been demonstrated, which, under favorable conditions (low natural ground vibrations), enables step-by-step registration of human activity at distances up to 350-370 m from the sensor installation point in the ground. The advantages of three-dimensional (3D) SFCO seismic sensors, which allow detecting human activity even with unfavorable environmental parameters and filtering features of the soil due to their anisotropy, have been demonstrated. The possibility of detecting soil features with new SFCO sensors is also shown. Possible applications of vibration seismic SFCO sensors in other areas are also discussed.


Assuntos
Algoritmos , Vibração , Movimento
2.
J Comp Pathol ; 167: 50-59, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30898298

RESUMO

There is significant evidence that pathology of the microcirculation occurs in African swine fever (ASF); however, the mechanisms by which it develops are largely unknown. In the present experimental infection study, we show that an increase in vascular permeability in the initial stages of acute ASF is dependent on viraemia and elevation of the concentration of serum nitric oxide (NO). Macrophages activated by ASF virus (ASFV) are stimulated to produce NO and simultaneously to sensitize the endothelial cells through the action of vascular endothelial growth factor Β (VEGFΒ), which is followed by an increase in VEGF-mediated endothelial permeability. In the later stages of disease, the endothelial cells undergo DNA proliferation, which may additionally provoke capillary leakage, point haemorrhages and migration of blood cells into tissues. The possible mechanism of a shift in the cell cycle from the G1 to S and G2 stages could be a direct effect of ASFV. The terminal stages of disease are characterized by triggering of compensatory mechanisms such as stimulation of the synthesis of stromal cell-derived factor-1.


Assuntos
Febre Suína Africana/patologia , Quimiocina CXCL12/sangue , Endotélio Vascular/patologia , Óxido Nítrico/sangue , Fator A de Crescimento do Endotélio Vascular/sangue , Febre Suína Africana/metabolismo , Animais , Ciclo Celular/fisiologia , Proliferação de Células/fisiologia , Células Endoteliais/metabolismo , Células Endoteliais/patologia , Endotélio Vascular/metabolismo , Suínos
3.
Chem Sci ; 6(3): 1928-1931, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25705369

RESUMO

The Cu(I)-catalyzed denitrogenative transannulation reaction of pyridotriazoles with terminal alkynes en route to indolizines was developed. Compared to the previously reported Rh-catalyzed transannulation reaction, this Cu-catalyzed method features aerobic conditions and much broader scope of pyridotriazoles and alkynes.

4.
Chem Heterocycl Compd (N Y) ; 47(12): 1516-1526, 2012 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-24501430

RESUMO

Organocuprates efficiently undergo reaction with heterocyclic propargyl mesylates at low temperature to produce N-fused heterocycles. The copper reagent plays a "double duty" in this cascade transformation, which proceeds through an SN2'-substitution followed by a consequent cycloisomerization step.

6.
Org Lett ; 3(17): 2705-7, 2001 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-11506614

RESUMO

[reaction: see text]. A highly effective protocol for allylation of secondary benzylic alcohol derivatives with allylsilanes in the presence of catalytic amounts of B(C6F5)3 has been developed. Some additional functionalities, such as bromo, acetoxy, and primary benzyloxy groups, were tolerated under these conditions.

8.
J Org Chem ; 66(8): 2743-6, 2001 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-11304196

RESUMO

Several novel types of cyclophanes were efficiently synthesized via an intermolecular palladium-catalyzed cross-benzannulation of cyclic enynes and diynes. These types of cyclophanes are not accessible through an intramolecular mode of the homo-benzannulation protocol, reported previously. Cyclic reactants (enynes and diynes) were readily prepared in reasonable yields from commercially available materials using known procedures. The fact that the cyclic Z-enyne 29, in contrast to its E-counterpart, underwent benzannulation to produce the cyclophane 28 brought additional support for the necessity of having an E-hydrogen atom at the terminal olefin moiety of nonactivated enynes, which was found previously in the benzannulation of the acyclic substrates.

9.
J Org Chem ; 66(8): 2835-41, 2001 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-11304209

RESUMO

A new concept of highly chemo- and regioselective formation of the benzene ring by a palladium-catalyzed formal [2 + 2 + 2] sequential intermolecular trimerization of alkynes is proposed. Homodimerization of terminal alkynes and subsequent [4 + 2] benzannulation with diynes gives tetrasubstituted benzenes in moderate to good yields. The introduction of two different alkynes (terminal and internal) in the first step of the sequence allows for construction of pentasubstituted benzenes from three different acyclic acetylenic units. In all cases the tetra- and pentasubstituted benzenes are formed as a single reaction product without being accompanied by any of regio- or chemoisomers. A significant acceleration of the sequential trimerization reaction in the presence of Lewis acid/phosphine combined system was observed. Mechanistic studies reveal that the Lewis acid assisted isomerization of the E-enyne formed in the first step of the sequence to the more reactive Z-isomer is responsible for the observed acceleration effect. The proposed methodology provides a conceptually new and synthetically useful route to multifunctional aromatic compounds.

10.
J Org Chem ; 66(5): 1672-5, 2001 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-11262111

RESUMO

The aliphatic carboxylic group was efficiently reduced to the methyl group by HSiEt(3) in the presence of catalytic amounts of B(C(6)F(5))(3). To the best of our knowledge, this is the first example of a direct exhaustive reduction of aliphatic carboxylic function. Aliphatic aldehydes, acyl chlorides, anhydrides, and esters also underwent complete reduction under similar reaction conditions. Aromatic carboxylic acids, as well as other carbonyl functional equivalents, underwent smooth partial reduction to the corresponding TES-protected benzylic alcohols. It was shown that, unlike the reduction of aliphatic substrates, the exhaustive reduction of aromatic substrates was not straightforward: a concurrent Friedel-Crafts-like alkylation process competed with the reduction yielding trace to notable amounts of dimeric products, thus decreasing the overall selectivity of the reduction process.

11.
J Org Chem ; 65(19): 6179-86, 2000 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-10987957

RESUMO

The primary alcohols 1a-e and ethers 4a-d were effectively reduced to the corresponding hydrocarbons 2 by HSiEt(3) in the presence of catalytic amounts of B(C(6)F(5))(3). To the best of our knowledge, this is the first example of catalytic use of Lewis acid in the reduction of alcohols and ethers with hydrosilanes. The secondary alkyl ethers 4j,k enabled cleavage and/or reduction under similar reaction conditions to produce either the silyl ethers 3m-n or the corresponding alcohol 5a upon subsequent deprotection with TBAF. It was found that the secondary alcohols 1g-i and tertiary alcohol 1j, as well as the tertiary alkyl ether 4l, did not react with HSiEt(3)/(B(C(6)F(5))(3) reducing reagent at all. The following relative reactivity order of substrates was found: primary >> secondary > tertiary. A plausible mechanism for this nontraditional Lewis acid catalyzed reaction is proposed.

12.
J Org Chem ; 65(14): 4338-4341, 2000 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-10891135

RESUMO

Polysubstituted anilines were prepared by the palladium-catalyzed cross-benzannulation of conjugated aminoenynes 1-4 with diynes 8. The reaction proceeded in a highly regioselective manner under mild conditions, and the anilines were obtained as single regioisomers. Our method complements the well-known precedures for the preparation of polysubstituted anilines which are widely used in organic synthesis.

13.
J Org Chem ; 65(2): 568-72, 2000 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-10813973

RESUMO

Alkyl-, alkoxy-, and aryloxy-substituted conjugated enynes 1 in the presence of Pd(PPh(3))(4) catalyst smoothly underwent the regiospecific [4 + 2] cycloaddition reaction with conjugated alkyl- and alkoxy-substituted symmetric diynes 2 to give multisubstituted aryl ethers 3 in good to high yields. Benzannulation of enynes 1d-g with unsymmetric diyne 6, possessing alkyl and alkoxy groups at acetylenic terminii, in most cases produced an aromatic product 8 with an alkoxy group of diyne attached to the ethynyl moiety of the aromatic product. Remarkably, alkoxy-substituted diynes 2c and 6 underwent the benzannulation reaction with 1 at an unusually low temperature of 0 degrees C! One-pot consecutive benzannulation of alkyl-substituted enynes 1d,e and alkoxy-substituted enynes 1f,g with alkoxy-substituted diynes 2c and 6 followed by protonolysis with TsOH afforded coumaranones 9a-c and 10 in reasonable to high overall yields.

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