294 research outputs found
Correction of the state of cardiovascular system of undergraduates by means of dosed constitutional walking and jogging
The study is dedicated to the issue of educational process improving of physical education of undergraduates who has abnormalities in the state of cardiovascular system. Influence of researchers technique of dosed constitutional walking and jogging for functional state of cardiovascular system of undergraduates of special medical groups has been justified and experimentally verified in the studyyesBelgorod State National Research Universit
Synthesis of new 2-[2-(dialkyl(diaryl)-phosphoryl)-2-methylpropyl]quinoline-4-carboxylic acids
© 2015 Springer Science+Business Media New York. [Figure not available: see fulltext.] A Pfitzinger reaction of isatin with 2-methyl-(4-oxopent-2-yl)dialkyl(diphenyl)phosphine oxides was used to synthesize new derivatives of 4-quinolinecarboxylic acids, containing a phosphine oxide fragment, and screening for antimicrobial activity was performed
Synthesis and Antimicrobial Activity of New Dialkyl(diaryl)-2-(5-chloro-2-hydroxyphenyl)-2-(phenylethenyl)pentylphosphonium Salts
© 2018, Pleiades Publishing, Ltd. New dialkyl(diaryl)-2-(5-chloro-2-hydroxyphenyl)-2-(phenylethenyl)pentylphosphonium salts bearing various substituents at the phosphorus atom were synthesized. Antimicrobial activity of the salts obtained was estimated. Derivatives with 2-methoxyphenyl substituents at the phosphorus atom are most active against grampositive bacteria. Herewith, dibenzyl-substituted phosphonium derivatives possess the best antifungal activity
Synthesis of 2-(2-hydroxyaryl)alkenylphosphonium salts from phosphine oxides via ring-closing ring-opening approach and their antimicrobial evaluation
© 2016 Elsevier LtdA new two-step synthesis of phosphonium salts from phosphine oxides using Grignard reagents is reported. This approach involves a cyclization of Z-dialkyl-(diaryl)[2-(5-chloro-2-hydroxyphenyl)-2-phenylvinyl]phosphine oxides under the action of sulfinyl chloride with the formation of 2,2-dialkyl(diaryl)-6-chloro-4-phenyl-2H-1,2-benzoxaphosphinin-2-ium chlorides followed by ring opening under the action of organomagnesium compounds. The method was successfully applied to prepare a series of a new phosphonium salts bearing phenolic moiety with a wide range of substituents at phosphorus atom. Synthesized phosphonium salts shows high antibacterial and antifungal in vitro activity and low toxicity towards human red blood cell
Anticorrosive effects and antimicrobial properties of alkyldimethyl(hydroxyalkyl)ammonium bromides
Quaternary ammonium compounds containing the hydroxyalkyl moiety in the head group have been synthesized. These compounds exhibit a micelle-forming ability, high anticorrosive activity, and antimicrobial action. The compounds of the formula R(CH3)2N+(CH2CH 2CH2OH)Br- with R = C14H 29-C18H37 are characterized by a protective effect higher than 90-99% at 10 mg/l with respect to hydrogen sulfide corrosion, inhibiting properties against carbon dioxide corrosion (84-98% at 10-25 mg/l), and bactericidal action on sulfate-reducing bacteria (10-50 mg/l). © 2011 Pleiades Publishing, Ltd
Wind Accretion and State Transitions in Cygnus X-1
We present the results of a spectroscopic monitoring program (from 1998 to
2002) of the H-alpha emission strength in HDE 226868, the optical counterpart
of the black hole binary, Cyg X-1. The H-alpha profiles consist of (1) a P
Cygni component associated with the wind of the supergiant, (2) emission
components that attain high velocity at the conjunctions and that probably form
in enhanced outflows both towards and away from the black hole, and (3) an
emission component that moves in anti-phase with the supergiant's motion. We
argue that the third component forms in accreted gas near the black hole, and
the radial velocity curve of the emission is consistent with a mass ratio of
M_X / M_opt = 0.36 +/- 0.05. We find that there is a general anti-correlation
between the H-alpha emission strength and X-ray flux in the sense that when the
H-alpha emission is strong (W_\lambda < -0.5 Angstroms) the X-ray flux is
weaker and the spectrum harder. On the other hand, there is no correlation
between H-alpha emission strength and X-ray flux when H-alpha is weak. During
the low/hard X-ray state, the strong wind is fast and the accretion rate is
relatively low, while in the high/soft state the weaker, highly ionized wind
attains only a moderate velocity and the accretion rate increases. We argue
that the X-ray transitions from the normal low/hard to the rare high/soft state
are triggered by episodes of decreased mass loss rate in the supergiant donor
star.Comment: 45 pages, 16 figures, ApJ, in pres
Aggregation behavior, anticorrosion effect, and antimicrobial activity of alkylmethylmorpholinium bromides
Quaternary ammonium derivatives containing a morpholinium moiety in the head group and exhibiting micelle-forming activity have been synthesized and characterized. These compounds exhibit poly-functional properties: they efficiently inhibit hydrogen sulfide and combined (H2S and CO 2) corrosion of steel, are characterized by strong bactericidal activity against sulfate-reducing bacteria, and possess pronounced bacteriostatic and fungistatic effects. © 2014 Pleiades Publishing, Ltd
On the Change of the Inner Boundary of an Optically Thick Accretion Disk around White Dwarfs Using the Dwarf Nova SS Cyg as an Example
We present the results of our studies of the aperiodic optical flux
variability for SS Cyg, an accreting binary systemwith a white dwarf. The main
set of observational data presented here was obtained with the ANDOR/iXon
DU-888 photometer mounted on the RTT-150 telescope, which allowed a record(for
CCD photometers) time resolution up to 8 ms to be achieved. The power spectra
of the source's flux variability have revealed that the aperiodic variability
contains information about the inner boundary of the optically thick flow in
the binary system. We show that the inner boundary of the optically thick
accretion disk comes close to the white dwarf surface at the maximum of the
source's bolometric light curve, i.e., at the peak of the instantaneous
accretion rate onto the white dwarf, while the optically thick accretion disk
is truncated at distances 8.5e9 cm ~10 R_{WD} in the low state. We suggest that
the location of the inner boundary of the accretion disk in the binary can be
traced by studying the parameters of the power spectra for accreting white
dwarfs. In particular, this allows the mass of the accreting object to be
estimated.Comment: 9 pages, 7 figures, Published in Astronomy Letter
- …