Stability of the photonic band gap in the presence of disorder

The photonic eigenmodes near a band gap of a type of one-dimensional disordered photonic crystal have been investigated statistically. For the system considered, it is found that the tail of the density of states entering the band gap is characterized by a certain penetration depth, which is proportional to the disorder parameter. A quantitative relation between the relative penetration depth, the relative width of the photonic band gap, and the disorder has been found. It is apparent that there is a certain level of disorder below which the probability of the appearance of photonic eigenstates at the center of the photonic band gap essentially vanishes. Below the threshold, the ensemble-averaged transmission at the center of the photonic band gap does not change significantly with increasing disorder, but above threshold it increases much more rapidly. A simple empirical formula has been obtained which describes how the logarithm of the transmission relates to the periodic refractive index modulation and the disorde

«Неожиданные» инфекции при асептических ревизиях

Background. Data from the national registers of arthroplasty showed that about 12% of hip and knee arthroplasty undergo revision within 10 years after the primary surgery. The leading cause of hip revisions is aseptic loosening of components, knee joint periprosthetic infection (PPI). Some of the infectious complications, including those related to mechanical causes, remain out of sight. The aim of the study was to identify the frequency of unexpected infections during revision knee and hip arthroplasty performed for aseptic complications of any etiology. Materials and Methods. 839 cases of revision arthroplasty of knee and hip joints were analyzed, including 485 aseptic revisions in 450 patients. Clinical, X-ray, laboratory (complete blood count and comprehensive metabolic panel, coagulation panel) methods, synovial fluid analysis and microbiological examination of punctures, including intraoperative ones, were used. The ICM and EBJIS (European Bone and Joint Infections Society) consensus recommendations were used as criteria for assessing the presence of infection. Results. The average age of patients at the time of the revision was 61.7 years. The hip joint prevailed (59.4%), knee joint 40.6%. The growth of microorganisms in the intraoperative biomaterial was detected in 2.08% of observations: in 10 out of 287 patients after aseptic revision of the hip joints and in none of the 198 revisions of the knee joints. In 8 out of 10 cases, the causative agents were coagulase-negative staphylococci, including 6 MRSE; in two cases, anaerobic bacteria. All revisions were carried out by a one-stage method. Patients with detected PPI underwent systemic antibacterial therapy. At the stage of catamnesis, reinfection was assumed in one of the 10 identified cases of PPI, the patient did not show up for revision. In control 63% of the group of the other (aseptic) 470 patients, PPI developed in 4 cases, two-stage revisions were carried out. Conclusions. The frequency of infections accidentally detected during aseptic revisions of large joints was 2.08%. Three-time examination of joint punctures, including intraoperative, provides additional opportunities for the diagnosis of PPI during aseptic revision, and also allows you to choose the optimal stage of revision treatment. The experience gained makes it possible in certain cases to perform one-stage revision in the treatment of PPI.Актуальность. Данные мировых регистров артропластики суставов показали, что около 12% эндопротезов тазобедренного и коленного суставов подвергаются ревизионным вмешательствам в течение 10 лет после первичной операции. Лидирующая причина ревизий тазобедренного сустава асептическое расшатывание компонентов, коленного перипротезная инфекция (ППИ). Часть инфекционных осложнений, в т.ч. связанных с механическими причинами, остается вне поля зрения врачей. Целью работы является выявление частоты неожиданных инфекций при ревизионном эндопротезировании коленных и тазобедренных суставов, выполненном по поводу асептических осложнений любой этиологии. Материал и методы. Проанализировано 839 случаев ревизионного эндопротезирования коленного (КС) и тазобедренного (ТБС) суставов, в том числе 485 асептических ревизий у 450 пациентов. Применялись клинический, рентгенологический, лабораторный (общий и биохимический анализы крови, коагулограмма) методы, анализ синовиальной жидкости и микробиологическое исследование пунктатов, в т.ч. интраоперационных. В качестве критериев оценки наличия инфекции использовали рекомендации консенсуса ICM и EBJIS (Европейского общества по инфекциям костей и суставов). Результаты. Средний возраст пациентов на момент ревизии составил 61,7 года. На ТБС выполнено 59,4% ревизионных операций, на КС 40,6%. Рост микроорганизмов в интраоперационном биоматериале обнаружен в 2,08% наблюдений: у 10 из 287 пациентов после асептической ревизии тазобедренных суставов и ни в одном случае из 198 ревизий коленных суставов. В 8 из 10 случаев возбудителями были коагулазо-негативные стафилококки, в том числе в 6 MRSE; в двух случаях анаэробные бактерии. Все ревизии проведены одноэтапным методом. Пациентам с обнаруженной ППИ проведена системная антибактериальная терапия. На этапе катамнеза в одном из 10 выявленных случаев ППИ предполагалась реинфекция, пациент на ревизию не явился. При контроле 63% из группы остальных (асептических) 470 пациентов в 4 случаях развилась ППИ , проведены двухэтапные ревизии. Заключение. Частота инфекций, случайно обнаруженных при асептических ревизиях крупных суставов, составила в 2,08%. Трехкратное исследование пунктатов сустава, в т.ч. интраоперационных, предоставляет дополнительные возможности диагностики ППИ при асептической ревизии, а также позволяет избрать оптимальную этапность ревизионного лечения. Полученный опыт позволяет в определенных случаях при лечении ППИ выполнять одноэтапное реэндопротезирование

Optimal affine image normalization approach for optical character recognition

Optical character recognition (OCR) in images captured from arbitrary angles requires preliminary normalization, i.e. a geometric transformation resulting in an image as if it was captured at an angle suitable for OCR. In most cases, a surface containing characters can be considered flat, and a pinhole model can be adopted for a camera. Thus, in theory, the normalization should be projective. Usually, the camera optical axis is approximately perpendicular to the document surface, so the projective normalization can be replaced with an affine one without a significant loss of accuracy. An affine image transformation is performed significantly faster than a projective normalization, which is important for OCR on mobile devices. In this work, we propose a fast approach for image normalization. It utilizes an affine normalization instead of a projective one if there is no significant loss of accuracy. The approach is based on a proposed criterion for the normalization accuracy: root mean square (RMS) coordinate discrepancies over the region of interest (ROI). The problem of optimal affine normalization according to this criterion is considered. We have established that this unconstrained optimization is quadratic and can be reduced to a problem of fractional quadratic functions integration over the ROI. The latter was solved analytically in the case of OCR where the ROI consists of rectangles. The proposed approach is generalized for various cases when instead of the affine transform its special cases are used: scaling, translation, shearing, and their superposition, allowing the image normalization procedure to be further accelerated.This work was partially financially supported by the Russian Foundation for Basic Research, projects 18-29-26035 and 17-29-03370

Modeling of spontaneous emission in presence of cylindrical nanoobjects: the scattering matrix approach

We propose a method of analysis of spontaneous emission of a quantum emitter (an atom, a luminescence center, a quantum dot) inside or in vicinity of a cylinder. At the focus of our method are analytical expressions for the scattering matrix of the cylindrical nanoobject. We propose the approach to electromagnetic field quantization based of eigenvalues and eigenvectors of the scattering matrix. The method is applicable for calculation and analysis of spontaneous emission rates and angular dependences of radiation for a set of different systems: semiconductor nanowires with quantum dots, plasmonic nanowires, cylindrical hollows in dielectrics and metals. Relative simplicity of the method allows obtaining analytical and semi-analytical expressions for both cases of radiation into external medium and into guided modes.The work has been supported by the Russian Science Foundation 21-12-00304

Алгоритм обработки масс-спектрометрических данных для получения диагностической панели молекулярных соединений на примере поиска маркеров метастазирования при раке молочной железы

A pathology diagnostic using molecular marker is a perspective direction of clinical medicine. Mass-spectrometry (MS) is a one of methods, which are used for obtaining information about molecular profiles. Selection of species, essential for classification “case/control is an important task for data processing. Pipeline of data processing has been proposed using MS data, obtained during analysis of tumor breast tissue samples and health breast tissue samples, with the aim of metastasis marker selection. As a result, selection of lipid markers that belong to classes, related to metastasis and proliferation processes, makes it possible to create high sensitivity diagnostic model, based on logistic regression. The proposed method is applicable for data processing, obtained by MS analysis of other “omics”: metabolome, proteome, glycome.Диагностика патологии по молекулярным маркерам является перспективным направлением клинической медицины, в котором масс-спектрометрия (МС) яслужит одним из методов, используемых для получения информации о молекулярных профилях. В контексте извлечения соединений, играющих ключевую роль для классификации патология/болезнь, важное значение имеет обработка полученных данных, часто включающих несколько сотен детектированных соединений. В данной работе предложен алгоритм обработки данных на примере данных МС, полученных при анализе опухолевой ткани и здоровой молочной железы, с целью выделения липидных маркеров метастазирования. В результате его реализации получен набор соединений, относящихся к классам липидов, связанных с процессами метастазирования и пролиферации, и позволяющих построить высокочувствительную диагностическую модель на основе логистической регрессии. Предложенный метод потенциально пригоден для обработки данных МС, полученных при анализе молекулярного профиля биоматериала другого базиса (метаболом, протеом, гликом)

Current state of the research on optoacoustic fiber-optic ultrasonic transducers based on thermoelastic effect and fiber-optic interferometric receivers

The work is devoted to an overview of the current state of optoacoustic fiber-optic ultrasonic transducers based on thermoelastic effect and fiber-optic interference receivers, its scope, technologies and materials used, the advantages and disadvantages of different methods and the prospects for the development of the industry.The work has been supported by the Russian Science Foundation 21-12-00304

The triple-pomeron regime and the structure function of the pomeron in the diffractive deep inelastic scattering at very small x

Misprints and numerical coefficients corrected, a bit of phenomenology and one figure added. The case for the linear evolution of the unitarized structure functions made stronger.Comment: KFA-IKP(Th)-1993-17, Landau-16/93, 46 pages, 14 figures upon request from N.Nikolaev, [email protected]

Towards a unified framework for identity documents analysis and recognition

Identity documents recognition is far beyond classical optical character recognition problems. Automated ID document recognition systems are tasked not only with the extraction of editable and transferable data but with performing identity validation and preventing fraud, with an increasingly high cost of error. A significant amount of research is directed to the creation of ID analysis systems with a specific focus for a subset of document types, or a particular mode of image acquisition, however, one of the challenges of the modern world is an increasing demand for identity document recognition from a wide variety of image sources, such as scans, photos, or video frames, as well as in a variety of virtually uncontrolled capturing conditions. In this paper, we describe the scope and context of identity document analysis and recognition problem and its challenges; analyze the existing works on implementing ID document recognition systems; and set a task to construct a unified framework for identity document recognition, which would be applicable for different types of image sources and capturing conditions, as well as scalable enough to support large number of identity document types. The aim of the presented framework is to serve as a basis for developing new methods and algorithms for ID document recognition, as well as for far more heavy challenges of identity document forensics, fully automated personal authentication and fraud prevention.This work was partially supported by the Russian Foundation for Basic Research (Project No. 18-29-03085 and 19-29-09055)

X-ray tomography: the way from layer-by-layer radiography to computed tomography

The methods of X-ray computed tomography allow us to study the internal morphological structure of objects in a non-destructive way. The evolution of these methods is similar in many respects to the evolution of photography, where complex optics were replaced by mobile phone cameras, and the computers built into the phone took over the functions of high-quality image generation. X-ray tomography originated as a method of hardware non-invasive imaging of a certain internal cross-section of the human body. Today, thanks to the advanced reconstruction algorithms, a method makes it possible to reconstruct a digital 3D image of an object with a submicron resolution. In this article, we will analyze the tasks that the software part of the tomographic complex has to solve in addition to managing the process of data collection. The issues that are still considered open are also discussed. The relationship between the spatial resolution of the method, sensitivity and the radiation load is reviewed. An innovative approach to the organization of tomographic imaging, called “reconstruction with monitoring”, is described. This approach makes it possible to reduce the radiation load on the object by at least 2 – 3 times. In this work, we show that when X-ray computed tomography moves towards increasing the spatial resolution and reducing the radiation load, the software part of the method becomes increasingly important.This work was supported by Russian Foundation for Basic Research (Projects No.18-29-26033, 18-29-26020)