1,303 research outputs found
Phase diagram of 2D array of mesoscopic granules
A lattice boson model is used to study ordering phenomena in regular 2D array
of superconductive mesoscopic granules, Josephson junctions or pores filled
with a superfluid helium. Phase diagram of the system, when quantum
fluctuations of both the phase and local superfluid density are essential, is
analyzed both analytically and by quantum Monte Carlo technique. For the system
of strongly interacting bosons it is found that as the boson density is
increased the boundary of ordered superconducting state shifts to {\it lower
temperatures} and at approaches its limiting position corresponding
to negligible relative fluctuations of moduli of the order parameter (as in an
array of "macroscopic" granules). In the region of weak quantum fluctuations of
phases mesoscopic phenomena manifest themselves up to . The mean
field theory and functional integral - expansion results are shown to
agree with that of quantum Monte Carlo calculations of the boson Hubbard model
and its quasiclassical limit, the quantum XY model.Comment: 7 pages, 5 Postscript figure
New model for system of mesoscopic Josephson contacts
Quantum fluctuations of the phases of the order parameter in 2D arrays of
mesoscopic Josephson junctions and their effect on the destruction of
superconductivity in the system are investigated by means of a quantum-cosine
model that is free of the incorrect application of the phase operator. The
proposed model employs trigonometric phase operators and makes it possible to
study arrays of small superconducting granules, pores filled with superfluid
helium, or Josephson junctions in which the average number of particles
(effective bosons, He atoms, and so on) is small, and the standard approach
employing the phase operator and the particle number operator as conjugate ones
is inapplicable. There is a large difference in the phase diagrams between
arrays of macroscopic and mesoscopic objects for and ( is
the characteristic interaction energy of the particle per granule and is
the Josephson coupling constant). Reentrant superconductivity phenomena are
discussed.Comment: 4 pages, 3 Postscript figure
Josephson array of mesoscopic objects. Modulation of system properties through the chemical potential
The phase diagram of a two-dimensional Josephson array of mesoscopic objects
is examined. Quantum fluctuations in both the modulus and phase of the
superconducting order parameter are taken into account within a lattice boson
Hubbard model. Modulating the average occupation number of the sites in
the system leads to changes in the state of the array, and the character of
these changes depends significantly on the region of the phase diagram being
examined. In the region where there are large quantum fluctuations in the phase
of the superconducting order parameter, variation of the chemical potential
causes oscillations with alternating superconducting (superfluid) and normal
states of the array. On the other hand, in the region where the bosons interact
weakly, the properties of the system depend monotonically on . Lowering
the temperature and increasing the particle interaction force lead to a
reduction in the width of the region of variation in within which the
system properties depend weakly on the average occupation number. The phase
diagram of the array is obtained by mapping this quantum system onto a
classical two-dimensional XY model with a renormalized Josephson coupling
constant and is consistent with our quantum Path-Integral Monte Carlo
calculations.Comment: 12 pages, 8 Postscript figure
A New High Energy Photon Tagger for the H1 - Detector at HERA
The H1 detector at HERA has been upgraded by the addition of a new
electromagnetic calorimeter. This is installed in the HERA tunnel close to the
electron beam line at a position 8m from the interaction point in the electron
beam direction. The new calorimeter extends the acceptance for tagged
photoproduction events to the high y range, 0.85 < y < 0.95, and thus
significantly improves the capability of H1 to study high energy gamma-p
processes. The calorimeter design, performance and first results obtained
during the 1996-1999 HERA running are described.Comment: 17 pages, 16 figure
Tagging High Energy Photons in the H1 Detector at HERA
Measures taken to extend the acceptance of the H1 detector at HERA for
photoproduction events are described. These will enable the measurement of
electrons scattered in events in the high y range 0.85 < y < 0.95 in the 1998
and 1999 HERA run period. The improvement is achieved by the installation of an
electromagnetic calorimeter, the ET8, in the HERA tunnel close to the electron
beam line 8 m downstream of the H1 interaction point in the electron direction.
The ET8 will allow the study of tagged gamma p interactions at centre-of-mass
energies significantly higher than those previously attainable. The calorimeter
design and expected performance are discussed, as are results obtained using a
prototype placed as close as possible to the position of the ET8 during the
1996 and 1997 HERA running.Comment: 13 pages, 13 figure
Toxic properties and allelopathic activity of Melilotus officinalis (L.) Pall.
Melilotus officinalis (L.) Pall., known as yellow sweetclover (Fabaceae), is widely used in medicine and agriculture. At the same time, yellow sweetclover is a weed and invasive plant in Siberia. In Russia, M. officinalis is cultivated as a valuable medicinal, fodder and honey plant. Its widespread use is due to its high ecological plasticity. In recent years, an interest in cultivation of M. officinalis as a low maintenance multipurpose crop has increased in biological agriculture. The herb M. officinalis contains a rich complex of biologically active compounds. However, along with positive properties, this species, though with a rich chemical composition and high physiological activity, is toxic towards different groups of living organisms. The toxic effect of M. officinalis extracts is primarily due to the presence of coumarin. A high allelopathic activity of M. officinalis was revealed. The phytotoxic effect of herb extracts on germination of crop and weed seeds was studied in detail. Data on the fungicidal and insecticidal activity of M. officinalis were obtained. Laboratory and in situ studies showed that the aboveground part of M. officinalis is a potential source of biopesticides with a broad-spectrum effect (bioherbicidal, insecticidal and fungicidal)
Influence of vesicourethral segment reconstruction techniques in radical prostatectomy on urinary continence: evaluation of immediate and long-term outcomes
Introduction. Currently, various methods and modifications of radical prostatectomy (RP) have been developed and tested, aimed at preventing and minimizing the development of urinary incontinence (UI). However, UI remains an urgent problem in patients who undergo RP, especially at the early follow-up stages.Objective. To evaluate and compare the effectiveness of modified reconstructive techniques for vesicourethral anastomosis in radical prostatectomy for the prevention of urinary incontinence with respect to the standard technique at different follow-up periods.Materials and methods. Design: single-centre, clinical, simple, comparative, parallel-group study with retrospective and prospective material evaluation, conducted in 2017 – 2022. Patients: men with verified prostate cancer cT1a – 2cN0 – xM0 without decompensated comorbidities. Age: 45 – 78 years. Retrospective part — group (G) 1: 90 patients who underwent non-nerve-sparing open retropubic RP with a "classic" vesicourethral anastomosis (VUA). Prospective part — G2: 46 patients who underwent similar surgery with modified VUA in two variations: without and with prostatic urethra-sparing — G2a (n = 25) and G2b (n = 21), respectively. Initial examination: standard preoperative laboratory and instrumental examination, assessment of lower urinary tract symptoms (LUTS) using the IPSS-QoL questionnaire. Follow-up examination: objective evaluation of UI according to established criteria and subjective assessment using the ICIQ-SF questionnaire, tracking the dynamics of LUTS using IPSS-QoL. Follow-up periods: 0-point (after catheter removal), 1, 3, 6, and 12 months (exit-point); the dynamics of recovery of urinary continence (UC) was determined monthly. Statistical analysis: Statistica ver.10.0 (StatSoft Inc., Tulsa, OK, USA) using non-parametric methods (CL p < 0.05 at a = 0.05)Results. Preoperative demographic, questionnaire and instrumental statistics did not differ (p > 0.05) between the groups, confirming the homogeneity of the samples. After RP, the urethral catheter was removed in a period of 7 to 21 days. There was no difference (p > 0.05) in the duration of drainage between the groups. Total urinary continence (TUC) immediately after catheter removal was detected in G1, G2a and G2b in 20.0%, 44.0% and 57.1% of cases, respectively. Subsequent objective monitoring of UC recovery from 1 month showed differences (p < 0.001) between the groups in the dynamics of rehabilitation during the year. The improvement in UC over the one-year follow-up period was cumulatively achieved in G1, G2a and G2b in 48.9%, 44.0% and 33.3% of cases, respectively. Total UI persisted in G1 and G2a by month 12 in 22.2% and 8.0% of patients, respectively, and was not detected in G2b. The severity of UI by the end of the follow-up according to the ICIQ-SF data was the most pronounced (p < 0.001) in patients from G1. TUC-patients in all groups from 1 month showed a marked decrease in the severity of obstructive and irritative LUTS and improved quality of life, with no differences (0.157 < p < 0.390) in IPSS-QoL values between groups.Conclusions. The use of modified VUA reconstruction techniques made it possible, compared with the standard one, to achieve high continence rates in patients both immediately after the removal of the urethral catheter and at subsequent follow-up periods, without the formation of severe iatrogenic obstruction. Prostatic urethra-sparing modification is the most effective technique that provided the rehabilitation of UI to a complete and/or social level in all patients within a year after surgery
Pharmacovigilance system in Eurasian Economic Union
The article deals with the main provisions of the basic document — «Rules of good practice of pharmacovigilance of the Eurasian economic Union», which regulates the study and prevention of adverse reactions and other problems associated with drugs in the member States of the Union, including the Russian Federation. Also, the Rules establish requirements for the organization of pharmacovigilance system in pharmaceutical companies, detail the work of manufacturers in the field of risk management, as well as determine the procedure for informing employees of the pharmaceutical industry and specialists of medical institutions of the authorized bodies about the identified safety problems in the use of medicines
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