251 research outputs found

    Interband electron Raman scattering in a quantum wire in a transverse magnetic field

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    Electron Raman scattering (ERS) is investigated in a parabolic semiconductor quantum wire in a transverse magnetic field neglecting by phonon-assisted transitions. The ERS cross-section is calculated as a function of a frequency shift and magnetic field. The process involves an interband electronic transition and an intraband transition between quantized subbands. We analyze the differential cross-section for different scattering configurations. We study selection rules for the processes. Some singularities in the Raman spectra are found and interpreted. The scattering spectrum shows density-of-states peaks and interband matrix elements maximums and a strong resonance when scattered frequency equals to the "hybrid" frequency or confinement frequency depending on the light polarization. Numerical results are presented for a GaAs/AlGaAs quantum wire.Comment: 8 pages, 5 figure

    MODELING OF THERMOELECTRIC SYSTEM FOR LOCAL THERMAL EFFECTS ON HUMAN FOREARM ZONE

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    In this paper we consider a model of the thermoelectric system for the thermal effect on the human forearm. The model is implemented on the basis of numerical solution of differentialequations of heat conduction for bodies of complex configuration. Two-dimensional and onedimensional graphs of the temperature change in different zones of the object of exposure aregiven

    Spectropolarimetric Observations of Herbig Ae/Be Stars. II. Comparison of Spectropolarimetric Surveys: HAeBe, Be and Other Emission-Line Stars

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    The polarization of light across individual spectral lines contains information about the circumstellar environment on very small spatial scales. We have obtained a large number of high precision, high resolution spectropolarimetric observations of Herbig Ae/Be, Classical Be and other emission-line stars collected on 117 nights of observations with the HiVIS spectropolarimeter at a resolution of R=13000 on the 3.67m AEOS telescope. We also have many observations from the ESPaDOnS spectropolarimeter at a resolution of R=68000 on the 3.6m CFH telescope. In roughly ~2/3 of the so-called "windy" or "disky" Herbig Ae/Be stars, the detected H-alpha linear polarization varies from our typical detection threshold near 0.1% to over 2%. In all but one HAe/Be star the detected polarization effect is not coincident with the H-alpha emission peak but is detected in and around the obvious absorptive part of the line profile. The qu-loops are dominated by the polarization in this absorptive region. In several stars the polarization varies in time mostly in the absorptive component and is not necessarily tied to corresponding variations in intensity. This is a new result not seen at lower resolution. In the Be and emission-line stars, 10 out of a sample of 30 show a typical broad depolarization effect but 4 of these 10 show weaker effects only visible at high resolution. Another 5 of 30 show smaller amplitude, more complex signatures. Six stars of alternate classification showed large amplitude (1-3%) absorptive polarization effects. These detections are largely inconsistent with the traditional disk-scattering and depolarization models.Comment: Published in ApJS 180. 47 pages, 34 figures. Small corrections made to tex

    The microbial load and the severity of morphological changes in the prostate during infection with various titers of uropathogens: a comparison of data from an animal model study

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    Introduction. It has been established in an animal model that coagulase-negative staphylococci (Staphylococcus haemolyticus) and anaerobes (Peptococcus niger) cause the development of an acute inflammatory process in the prostate when inoculated with 103 CFU/ml. At the same time, data have been published indicating the pathogenic potential of these microorganisms on a titer of 102 CFU/ml. But it was confirmed for the model of acute obstructive pyelonephritis. In addition, the characteristics of the formation of the inflammatory response at different times were determined, which require detailed verification and comparative characteristics with those during infection with a causative uropathogen (Escherichia coli).Objective. Based on the results of the experiment, to carry out: 1) an evaluation of the relationship between the dynamics of microbial load and the degree of pathomorphological changes in prostate tissues during infection with various uropathogens in a titer of 103 CFU/ml; 2) an evaluation of the degree of microbial load and severity of histological changes in prostate tissues on follow-up day 7 with transurethral infection with various uropathogens in a subpathogenic titer of 102 CFU/ml; 3) a fundamental comparative analysis of the indicators of contamination and the severity of inflammatory changes on follow-up day 7 after the inoculation of various uropathogens in titers of 102 and 103 CFU/ml.Materials and methods. The animal model was performed using the FELASA and ARRIVE guidelines. Lab animals: 20 New Zealand rabbits. Uropathogens: E. coli, S. haemolyticus, and P. niger. Infectious titers: 102.3 cfu/ml. Uropathogen inoculation technique: topical transurethral. Randomization: all laboratory animals were divided into 4 groups depending on the uropathogen (3 experimental, 1 control). Follow-up periods: day 1, 3, 7 and 14 for a titer of 103 CFU/ml, and day 7 for a titer of 102 CFU/ml. At the end of the follow-up, euthanasia and autopsy were performed with the extraction of the urogenital organ complex. Hereafter, biopsies were taken from various parts of the prostate. Cultural and histological studies of prostate tissues were carried out using standard methods. The results were analyzed using Statistica 10.2 (StatSoft Inc., Tulsa, OK, USA) and GraphPad Prism 9 (GraphPad Software Inc., Graphpad Holdings LLC, San Diego, CA, USA) programs through descriptive and nonparametric statistics.Results. Bacterial contamination of prostate tissue was determined in all cases of infection with differences (p < 0.05) in some indicators between the E. coli and P. niger groups at different observation periods, but only in the case of inoculation of the test titer of 103 CFU/ml. Histological evaluation of prostate tissues after inoculation with 103 CFU/ml verified the presence of acute destructive changes in the prostate from the follow-up day 1, which were more pronounced in the S. haemolyticus and E. coli groups. However, similar characteristics of the development of the inflammatory process in the form of hyper-eosinophilic infiltration in the early stages and pronounced congestion of the prostatic glands were identified in the S. haemolyticus and P. niger groups. Comparison of trends in dynamic changes of microbial load (rise / decline) and severity of pathological changes (increase / resolution) in prostate tissues in established follow-up periods showed the presence of relative synchronization of trends (from days 1 to 7) in the S. haemolyticus and P. niger groups, and complete synchronization in the E. coli group. When comparing the median microbial load of the prostate on the follow-up day 7, no intergroup (p > 0.05) differences were found both in cases of infection with a titer of 103 CFU/ml, and when compared with the data on contamination for a test titer of 102 CFU/ml, at the same time observations. At once, when E. coli and S. haemolyticus were infected at a subpathogenic titer of 102 CFU/ml, inflammatory changes were recorded that had a mild diffuse character, in relation to those after inoculation of these pathogens in a titer of 103 CFU/ml. In turn, P. niger induced the development of low-intensity focal alteration in isolated areas of prostate tissues.Conclusions. Detailed analysis of culture and histological data showed that E. coli, S. haemolyticus and P. niger have significant pathogenic potential at titer of 103 CFU/ml. In turn, when the titer decreases to 102 CFU/ml, E. coli and S. haemolyticus retain their pathogenic potential, but the severity of the inflammatory reaction is significantly reduced. It was also found that a change in bacterial contamination affects the severity of the inflammatory process in all groups during seven follow-up days at a given test titer

    Influence of vesicourethral segment reconstruction techniques in radical prostatectomy on urinary continence: evaluation of immediate and long-term outcomes

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    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

    Investigation of conduction band structure, electron scattering mechanisms and phase transitions in indium selenide by means of transport measurements under pressure

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    In this work we report on Hall effect, resistivity and thermopower measurements in n-type indium selenide at room temperature under either hydrostatic and quasi-hydrostatic pressure. Up to 40 kbar (= 4 GPa), the decrease of carrier concentration as the pressure increases is explained through the existence of a subsidiary minimum in the conduction band. This minimum shifts towards lower energies under pressure, with a pressure coefficient of about -105 meV/GPa, and its related impurity level traps electrons as it reaches the band gap and approaches the Fermi level. The pressure value at which the electron trapping starts is shown to depend on the electron concentration at ambient pressure and the dimensionality of the electron gas. At low pressures the electron mobility increases under pressure for both 3D and 2D electrons, the increase rate being higher for 2D electrons, which is shown to be coherent with previous scattering mechanisms models. The phase transition from the semiconductor layered phase to the metallic sodium cloride phase is observed as a drop in resistivity around 105 kbar, but above 40 kbar a sharp nonreversible increase of the carrier concentration is observed, which is attributed to the formation of donor defects as precursors of the phase transition.Comment: 18 pages, Latex, 10 postscript figure

    PHASES High Precision Differential Astrometry of delta Equulei

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    delta Equulei is among the most well-studied nearby binary star systems. Results of its observation have been applied to a wide range of fundamental studies of binary systems and stellar astrophysics. It is widely used to calibrate and constrain theoretical models of the physics of stars. We report 27 high precision differential astrometry measurements of delta Equulei from the Palomar High-precision Astrometric Search for Exoplanet Systems (PHASES). The median size of the minor axes of the uncertainty ellipses for these measurements is 26 micro-arcseconds. These data are combined with previously published radial velocity data and other previously published differential astrometry measurements using other techniques to produce a combined model for the system orbit. The distance to the system is determined to within a twentieth of a parsec and the component masses are determined at the level of a percent. The constraints on masses and distance are limited by the precisions of the radial velocity data; we outline plans improve this deficiency and discuss the outlook for further study of this binary.Comment: Accepted by AJ. Complete versions of tables 2-7 now available at http://stuff.mit.edu/~matthew1/deltaEquTables/ (removed from astroph server

    DEFINITION OF PRODUCTS AND OUTPUT PYROLYSIS AND GASIFICATION DURING THE HEAT PROCESSING OF ORGANIC SUBSTANCES AND WASTE

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    Developed a method of yield and composition of pyrolysis gas gasification of solid carbonaceous residue in the process of thermal processing of organic substances.Разработана методика выхода и состава пиролизного газа газификации твердого углеродистого остатка в процессе термической переработки органосодержащих веществ

    Multi-stage urethroplasy for anterior urethral strictures: objective parameters of long-term efficacy and patient-reported outcomes

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    Introduction. Multi-stage urethral surgery is used in cases of the most complex urethral strictures. The evaluation of surgical treatment results given by patients is a significant criterion for the efficacy of urethroplasty along with the assessment of urethral patency through instrumental examinations.Objective. To evaluate the long-term efficacy of multistage urethroplasty for complex anterior urethral strictures considering the patients' quality of life and satisfaction with the surgical outcomes.Materials and methods. The study included 73 patients aged 18 – 84 years with anterior urethral strictures who underwent multi-stage urethroplasty in 2010 – 2019. Surgical and functional outcomes of urethroplasty were assessed through general blood and urine tests, physical examination, uroflowmetry, and retrograde urethrography and urethroscopy in case of urinary disorders.  Subjective parameters of treatment efficacy were studied using questionnaires: International Prostate Symptom Score (IPSS); Quality of life (QoL); Patient-reported Outcome Measure for Urethral Stricture Surgery (USS-PROM); Patient Global Impression of Improvement (PGI-I).Results. Recurrent urethral stricture was detected in 19 (26,0%) patients with the average follow-up period being 65 months. Independent urination was restored in 71 (97.3%) cases, including repeated interventions. After surgery, there was a significant increase in urinary flow rate parameters (Q max: 8.1 vs 19.1 ml/s, p < 0.0001; Q ave: 5.5 vs 10.7 ml/s; p = 0.0004), decrease in residual urine volume (62.4 vs 18.6 ml, p < 0.0001), decrease in total IPSS score (18.7 vs 5.7 points; p < 0.0001) and QoL index (4.3 vs 1 .8 points, p < 0.0001). A comparative analysis of preoperative and postoperative USS-PROM questionnaire results demonstrated an improvement in indicators assessing LUTS (12.9 vs 3.4 points; p < 0.0001; 3.6 vs 1.7 points; p < 0.0001), and urination-associated quality of life (2.6 vs 0.6 points; p < 0.0001) and overall health (EQ-5D index: 0.73 vs 0.91 points; p = 0.025; EQ-VAS: 68.0 vs 88.1 points, p = 0.004). Fifty-seven (81.4%) men were “very satisfied” or “satisfied” with the treatment outcomes, while nine (12.9%) respondents noted a moderate effect of residual urinary disorders on the quality of life. Significantly higher satisfaction was observed among cystostomy patients and in cases where repeated interventions were unnecessary.Conclusion. Multi-stage urethroplasty for complex anterior urethral strictures achieves efficacy in 97.3% of cases and is accompanied by high levels of quality of life and patient’s satisfaction during long-term follow-up
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