Open Hemispherical Imaging Dielectric Resonator with Whispering Gallery Modes

The imaging dielectric resonators with whispering gallery modes (WGMs) for the creation of a new class of millimeter wave solid-state oscillators, devices for the investigation of high temperature superconductors, were suggested. They contain a dielectric element as a semidisk or a cylinder or a hemisphere and a flat metal mirror. The latter is a necessary element for placing in the resonator field active elements or conductor samples of materials. There is an important question about the dependence of the resonant frequencies and Q-factor of these resonators on impedance of the resonator mirror. In the present paper new investigation results of the open hemispherical imaging dielectric resonator (HIDR) with WGMs are represented

About Resonant Modes at the Shielded Dielectric Hemisphere

The resonant modes, which are excited at the shielded dielectric hemisphere, are investigated by the theoretical and experimental methods. The low-Q-factor modes of air cavity and high-Q-factor whispering gallery modes of dielectric structure are existed together in the case of high radial index value. The Q-factor value of the whispering gallery modes of the shielded dielectric sphere with the certain correlation between the sizes of dielectric hemisphere and metal shield can be more great than the Q-factor of the whispering gallery modes of the similar open dielectric resonator

Whispering-Gallery Modes in Shielded Hemispherical Dielectric Resonators

The results of the numerical and experimental investigations of whispering-gallery (WG) modes in shielded hemispherical dielectric resonators are presented in this paper. It is shown that the Q factor of WG modes in the shielded resonator can be ten times much higher than the Q factor of the similar open hemispherical dielectric-resonator modes. Shielding the resonator can decrease the dimensions of both the dielectric hemisphere and resonator as a whole, saving the high-Q factor of WG modes. The usage of a cylindrical shield and local flat reflectors in the experiment provides the investigation of the high-Q factor of WG modes in the resonator

The Effect of Random Surface Inhomogeneities on Microresonator Spectral Properties: Theory and Modeling at Millimeter Wave Range

The influence of random surface inhomogeneities on spectral properties of open microresonators is studied both theoretically and experimentally. To solve the equations governing the dynamics of electromagnetic fields the method of eigen-mode separation is applied previously developed with reference to inhomogeneous systems subject to arbitrary external static potential. We prove theoretically that it is the gradient mechanism of wave-surface scattering which is the highly responsible for non-dissipative loss in the resonator. The influence of side-boundary inhomogeneities on the resonator spectrum is shown to be described in terms of effective renormalization of mode wave numbers jointly with azimuth indices in the characteristic equation. To study experimentally the effect of inhomogeneities on the resonator spectrum, the method of modeling in the millimeter wave range is applied. As a model object we use dielectric disc resonator (DDR) fitted with external inhomogeneities randomly arranged at its side boundary. Experimental results show good agreement with theoretical predictions as regards the predominance of the gradient scattering mechanism. It is shown theoretically and confirmed in the experiment that TM oscillations in the DDR are less affected by surface inhomogeneities than TE oscillations with the same azimuth indices. The DDR model chosen for our study as well as characteristic equations obtained thereupon enable one to calculate both the eigen-frequencies and the Q-factors of resonance spectral lines to fairly good accuracy. The results of calculations agree well with obtained experimental data.Comment: 17+ pages, 5 figure

The Schwarzian derivative and the Wiman-Valiron property

Consider a transcendental meromorphic function in the plane with finitely many critical values, such that the multiple points have bounded multiplicities and the inverse function has finitely many transcendental singularities. Using the Wiman-Valiron method it is shown that if the Schwarzian derivative is transcendental then the function has infinitely many multiple points, the inverse function does not have a direct transcendental singularity over infinity, and infinity is not a Borel exceptional value. The first of these conclusions was proved by Nevanlinna and Elfving via a fundamentally different method

ОЦЕНКА ФАКТОРОВ ПРОГНОЗА У БОЛЬНЫХ С ДИССЕМИНИРОВАННЫМ РАКОМ ПРЕДСТАТЕЛЬНОЙ ЖЕЛЕЗЫ С УЧЕТОМ ОБЪЕМА МЕТАСТАТИЧЕСКОГО ПОРАЖЕНИЯ СКЕЛЕТА

Purpose. To determine the correlation between prognostic factors (age, differentiation grade assessed using the Gleason scoring system, serum prostate specific antigen, prostate volume, and serum testosterone) and the volume of skeletal metastasis expressed as bone metastasis index (BMI) in patients with disseminated prostate cancer (DPC). Material and methods. We conducted a retrospective analysis of 157 patients with initially diagnosed DPC treated at the Khabarovsk Regional Cancer Center from 2003 to 2013. Bone metastases were revealed in all patients. The volume of skeletal metastasis was measured using a novel automated computeraided diagnosis system devised by the specialists of Computer Center of the Russian Academy of Sciences. Results. The patients were divided into four groups. Group1: BMI≤1 % and Gleason score≤5; group 2: BMI ≤1 % and Gleason Score≥3; group 3: BMI>1 % and Gleason score≤5; group 4: BMI>1 % and Gleason score>5. The median survival time was 48 months in group 1 patients, 36.5 months in group 2, 33 months in group 3 and 20 months in group 4 patients. Both log-rank and Wilcoxon tests demonstrated a statistically significant difference in survival curves between the groups 1 and 3, and between the groups 2 and 4. There was also a difference in differentiation grade assessed by the Gleason score system between these two pairs of groups. Correlation of other prognostic factors, such as age, serum prostate specific antigen, prostate volume, and serum testosterone with the volume of skeletal metastasis demonstrated that BMI predominantly influenced the survival of prostate cancer patients. Conclusion. The assessment of prognostic factors allowed the patients’ groups with the worst prognosis to be identified. The bone metastasis index and differentiation grade of the tumor appeared to be independent predictors of high death risk in patients with disseminated prostate cancer.Цель исследования – изучение взаимосвязей факторов прогноза (возраст, степень дифференцировки опухоли по Глисону, простатспецифический антиген, объем предстательной железы, сывороточный тестостерон) у больных с диссеминированным раком предстательной железы (ДРПЖ) с объемом поражения скелета, выраженного в костном метастатическом индексе (КМИ). Материал и методы. Проведен ретроспективный анализ амбулаторных карт 158 пациентов с впервые выявленным ДРПЖ, проходивших лечение на базе Хабаровского краевого клинического центра онкологии в период с 2003 по 2013 г. Костные метастазы были у всех пациентов. Объем поражения скелета рассчитан с применением системы автоматизированной компьютерной диагностики, разработанной в ВЦ ДВО РАН, основанной на принципах распознавания изображений, обладающей функциями экспертного анализа и адаптированной к среде MATLAB. результаты. Выборка пациентов была распределена на четыре группы: 1 – КМИ до 1 %, Глисон – до 5 баллов; 2 – КМИ до 1 %, Глисон – более 5 баллов; 3 – КМИ более 1 %, Глисон – до 5 баллов; 4 – КМИ более 1 %, Глисон – более 5 баллов. Медиана выживаемости первой группы составила 48 мес, второй – 36,5 мес, третьей – 33 мес, четвертой – 20 мес. Различия выжи- ваемости между первой и третьей, второй и четвертой группами достоверны по Гехана – Вилкоксона и лог-ранговому критериям. Обе сравниваемые пары различаются по критерию дифференцировки опухоли по Глисону. Комбинация других факторов прогноза (возраст, простатспецифический антиген, объем предстательной железы, сывороточный тестостерон) с объемом поражения скелета показала преобладающее влияние на выживаемость больных фактора КМИ. выводы. При прогнозировании выживаемости у больных с ДРПЖ оценка нескольких факторов прогноза позволяет выделять группы с наихудшим прогнозом. Костный метастатический индекс и степень дифференцировки опухоли являются независимыми друг от друга предикторами высокого риска смерти у больных с ДРПЖ

ИССЛЕДОВАНИЕ ВОЗМОЖНОСТЕЙ КОМПЬЮТЕРНОГО АВТОМАТИЗИРОВАННОГО АНАЛИЗА ДЛЯ ЗАДАЧ ЭФФЕКТИВНОЙ ДИАГНОСТИКИ ДИССЕМИНИРОВАННОГО РАКА ПРЕДСТАТЕЛЬНОЙ ЖЕЛЕЗЫ

The aim. The possibility of applying a unified methodological approach to the problems of pattern recognition and information modeling of the process of diagnosis of various forms of malignant tumors with the help of CAD-analysis of medical images is substantiated. Material and methods. A retrospective analysis of medical histories and results of scintigraphy from 168 patients with newly diagnosed disseminated prostate cancer treated on the basis of the Khabarovsk regional clinical Oncology center in the period from 2003 to 2016. Considered original methodological approaches to the study of metastatic lesion of the skeleton using computer-aided analysis of planar osteoscintigraphy. Results. Volume of lesions of the skeleton were calculated with the use of computer systems for automated diagnostics based on the principles of image recognition and has the features of expert analysis. and the degree of tumor differentiation are independent of each other predictors of high risk of death in patients with disseminated prostate cancer. The high efficiency of CAD-analysis in the evaluation of bone metastatic index for this form of malignant advanced tumors is shown.Цель. Обоснована возможность применения единого методологического подхода к проблемам распознавания образов и информационного моделирования процесса диагностики различных форм злокачественных опухолей с помощью CAD-анализа медицинских изображений. Материал и методы. Проведен ретроспективный анализ историй болезни и результатов сцинтиграфии 168 пациентов с впервые диагностированным диссеминированным раком предстательной железы, пролеченных на базе Хабаровского краевого клинического онкологического центра в период с 2003 по 2016 год. Рассмотрены оригинальные методологические подходы к изучению метастатического поражения скелета с использованием компьютерного анализа планарной остеосцинтиграфии. Результаты. Объем поражений скелета рассчитан с использованием компьютерных систем автоматизированной диагностики на основе принципов распознавания образов и имеет особенности экспертного анализа. а степень дифференцировки опухолей не зависят друг от друга и являются предикторами высокого риска смерти у больных диссеминированным раком предстательной железы. Показана высокая эффективность CAD-анализа при оценке костного метастатического индекса для данной формы злокачественных опухолей