3,142 research outputs found

    Clinical mimics and diagnostic challenges in tick-borne borreliosis: a systematic review

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    Background. Ixodes tick-borne borreliosis (TBB) is a clinically multifaceted disease posing a serious threat in most territories of the Russian Federation. New TBB outbreaks emerge and spread to the country’s south.Objectives. The review highlights the TBB clinical diversity to physicians in order to improve the diagnosis quality and opportune aid. It focuses on the early and late clinical presentation of localised and disseminated polysystemic TBB.Methods. Sources were mined in the MEDLINE, PubMed and national electronic databases (Сyberleninka, eLibrary, etc.) with keywords “tick-borne borreliosis” [клещевой боррелиоз], “Lyme disease” [болезнь Лайма], “Lyme arthritis” [Лайм-артриты], neuroborreliosis [нейроборрелиоз] for the period of 2014–2020. Selected impactive publications within 2007–2013 were also included. Research was considered eligible if borreliosis was diagnosed using specific techniques like immune-enzyme assays, immunoblotting or PCR.Results. TBB is a common and cross-disciplinary situation. The disease may progress occult or manifest in a variety of forms, from annular erythema to cardiac, peripheral and central nervous system involvement or arthritis. The polysystemic nature of lesions, often long-term of the tick bite, forces multiple specialist visits ending with misdiagnoses, late aetiotropic therapy and transition into a chronic phase through ignorance of the patient’s epidemiological record. Some patients may have the acute phase followed by irreversible neurological damage associated with memory loss, cognitive decline, arthrosis and sclerotic skin change reducing the quality of life.Conclusion. TBB can be mimicked by therapeutic, neurological, skin and ophthalmic illnesses, which warrants the physician’s attention to the epidemiological record and knowledge of specific diagnostic techniques. Further research is necessary into the pathogenesis and clinical presentation of chronic TBB and its residual manifestations

    CHARACTERISTICS OF THE PROTECTIVE ANTIGEN COMPLEX OBTAINED FROM FRANCISELLA TULARENSIS SSP. NOVICIDA

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    F. tularensis ssp. novicida, considered earlier as a representative of a separate species, has been recently classed among F. tularensis variety, based on the results of comparative analysis of 16S-ribosomal RNA. Subspecies novicida can cause disease only in immunocompromised humans and is low virulent for rabbits. Despite this, high rate of homology of the nucleotide sequence of F. tularensis intraspecific taxon is established. Objective of the study is to obtain protective surface antigen complex from F. tularensis ssp. novicida Utah 112 (ATTC 15 482) cells and investigate its properties. Materials and methods. Protein, carbohydrate, and lipid content of the antigen preparation was measured using conventional colorimetric methods, SDS-PAGE was conducted according to U.Laemmli, and immunoblotting – to H.Towbin. For purification and molecular mass determination column chromatography was applied. Immune-chromatographic activity was analyzed by immune-enzyme assay. Immunogenicity of the produced preparation was tested on scrub white mice, with LD50 and ED50 calculated according to Karber’s method. Results and conclusions. Carried out has been comparative analysis of physical-chemical, antigenic and bio-chemical peculiarities of the protective antigen complex obtained from F. tularensis Utah 112 cells and equivalent antigen complex obtained from the vaccine strain – F. tularensis 15 NIIEG. Protectivity of the preparation has been tested through inoculation of the immunized white mice with virulent F. tularensis 503/840 strain. Demonstrated have been distinctive features of the new preparation, by structure and composition, as compared to similar antigen from the vaccine producer strain, as well as the slowdown of its immunochemical and protective activities

    Critical Exponents of the N-vector model

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    Recently the series for two RG functions (corresponding to the anomalous dimensions of the fields phi and phi^2) of the 3D phi^4 field theory have been extended to next order (seven loops) by Murray and Nickel. We examine here the influence of these additional terms on the estimates of critical exponents of the N-vector model, using some new ideas in the context of the Borel summation techniques. The estimates have slightly changed, but remain within errors of the previous evaluation. Exponents like eta (related to the field anomalous dimension), which were poorly determined in the previous evaluation of Le Guillou--Zinn-Justin, have seen their apparent errors significantly decrease. More importantly, perhaps, summation errors are better determined. The change in exponents affects the recently determined ratios of amplitudes and we report the corresponding new values. Finally, because an error has been discovered in the last order of the published epsilon=4-d expansions (order epsilon^5), we have also reanalyzed the determination of exponents from the epsilon-expansion. The conclusion is that the general agreement between epsilon-expansion and 3D series has improved with respect to Le Guillou--Zinn-Justin.Comment: TeX Files, 27 pages +2 figures; Some values are changed; references update

    Thermodynamic characteristics of the classical n-vector magnetic model in three dimensions

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    The method of calculating the free energy and thermodynamic characteristics of the classical n-vector three-dimensional (3D) magnetic model at the microscopic level without any adjustable parameters is proposed. Mathematical description is perfomed using the collective variables (CV) method in the framework of the ρ4\rho^4 model approximation. The exponentially decreasing function of the distance between the particles situated at the N sites of a simple cubic lattice is used as the interaction potential. Explicit and rigorous analytical expressions for entropy,internal energy, specific heat near the phase transition point as functions of the temperature are obtained. The dependence of the amplitudes of the thermodynamic characteristics of the system for T>TcT>T_c and T<TcT<T_c on the microscopic parameters of the interaction potential are studied for the cases n=1,2,3n=1,2,3 and nn\to\infty. The obtained results provide the basis for accurate analysis of the critical behaviour in three dimensions including the nonuniversal characteristics of the system.Comment: 25 pages, 5 figure

    Disorder-Induced Critical Phenomena in Hysteresis: Numerical Scaling in Three and Higher Dimensions

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    We present numerical simulations of avalanches and critical phenomena associated with hysteresis loops, modeled using the zero-temperature random-field Ising model. We study the transition between smooth hysteresis loops and loops with a sharp jump in the magnetization, as the disorder in our model is decreased. In a large region near the critical point, we find scaling and critical phenomena, which are well described by the results of an epsilon expansion about six dimensions. We present the results of simulations in 3, 4, and 5 dimensions, with systems with up to a billion spins (1000^3).Comment: Condensed and updated version of cond-mat/9609072,``Disorder-Induced Critical Phenomena in Hysteresis: A Numerical Scaling Analysis'

    Fe/Co Alloys for the Catalytic Chemical Vapor Deposition Synthesis of Single- and Double-Walled Carbon Nanotubes (CNTs). 1. The CNT−Fe/Co−MgO System

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    Mg0.90FexCoyO (x + y ) 0.1) solid solutions were synthesized by the ureic combustion route. Upon reduction at 1000 °C in H2-CH4 of these powders, Fe/Co alloy nanoparticles are formed, which are involved in the formation of carbon nanotubes, which are mostly single and double walled, with an average diameter close to 2.5 nm. Characterizations of the materials are performed using 57Fe Mo¨ssbauer spectroscopy and electron microscopy, and a well-established macroscopic method, based on specific-surface-area measurements, was applied to quantify the carbon quality and the nanotubes quantity. A detailed investigation of the Fe/Co alloys’ formation and composition is reported. An increasing fraction of Co2+ ions hinders the dissolution of iron in the MgO lattice and favors the formation of MgFe2O4-like particles in the oxide powders. Upon reduction, these particles form R-Fe/Co particles with a size and composition (close to Fe0.50Co0.50) adequate for the increased production of carbon nanotubes. However, larger particles are also produced resulting in the formation of undesirable carbon species. The highest CNT quantity and carbon quality are eventually obtained upon reduction of the iron-free Mg0.90Co0.10O solid solution, in the absence of clusters of metal ions in the starting material. Introduction Catalyti

    Rhinocerebral Form of Invasive Mycosis in COVID-19 Patients: Clinical Course, Diagnosis, Treatment Experience

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    Background. The incidence of invasive mycoses is reported to increase among patients with a history of new coronavirus infection COVID-19. Adhesion and damage of endothelial cells by zygomycetes lead to fungus angioinvasion, release of a large number of fungal proteases, lipases and mycotoxins, as well as vascular thrombosis, subsequent necrosis of tissues.Objectives. Improvement of the diagnosis and treatment for COVID-19 associated invasive mycosis.Methods. Examination and treatment of 143 patients with invasive mycosis of the maxillofacial area in the period from August 2021 to May 2022 at the Maxillofacial Unit of Regional Clinical Hospital of Emergency Medical Care, Krasnodar Krai, Russia. The diagnosis was confi rmed by cytological, culture-based methods, as well as pathomorphological study of surgical specimen. Follow-up monitoring was carried out in 1, 3, 6 months, with repeated CT and MRI investigations. The group under follow-up monitoring included 91 patients. The incidence of signs was determined via descriptive statistics methods in proportion of the total number of observations and expressed as a percentage. Statistika 12.5 and Excel 2010 (Windows 10) were used in the study, the graphical representation of the material was made in the same programs.Results. Manifestation of invasive mycoses of the maxillofacial area occurred during the early convalescent period of coronavirus infection in specialized infectious hospitals or within two weeks after discharge from the hospital. A typical clinical picture includes rhinocerebral zygomycosis with the development of fungal osteomyelitis of the upper jaw, nasal bones, zygomatic bone, ethmoidal labyrinth bones, sphenoid bone, frontal bone. 17 cases (11.9%) had a lethal outcome as a result of disseminated form of fungal infection caused by Mucorales (14 patients), Aspergillus (3 patients) with damage to the brain, lungs, kidneys and fatal massive necrotic lesions of the craniofacial area. An integrated approach embraced early antifungal therapy (Amphotericin B) as well as surgical debridement of the lesions and provided a positive effect in treatment.Conclusion. Invasive fungal infections require prompt diagnosis and early prescription of antifungal therapy (prior to histological confi rmation of diagnosis) to minimize consequences and prevent fatal outcome. Due to the nonspecifi c nature of clinical symptoms and diffi culties of early diagnosis of invasive zygomycosis and aspergillosis, it is necessary to be alert to potential invasive aggressive mycoses in immunocompromised patients who have a history of a new coronavirus infection COVID-19

    Three-loop critical exponents, amplitude functions, and amplitude ratios from variational perturbation theory

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    We use variational perturbation theory to calculate various universal amplitude ratios above and below T_c in minimally subtracted phi^4-theory with N components in three dimensions. In order to best exhibit the method as a powerful alternative to Borel resummation techniques, we consider only to two- and three-loops expressions where our results are analytic expressions. For the critical exponents, we also extend existing analytic expressions for two loops to three loops.Comment: Author Information under http://www.physik.fu-berlin.de/~kleinert/institution.html . Latest update of paper (including all PS fonts) at http://www.physik.fu-berlin.de/~kleinert/kleiner_re318/preprint.htm

    Zero modes, beta functions and IR/UV interplay in higher-loop QED

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    We analyze the relation between the short-distance behavior of quantum field theory and the strong-field limit of the background field formalism, for QED effective Lagrangians in self-dual backgrounds, at both one and two loop. The self-duality of the background leads to zero modes in the case of spinor QED, and these zero modes must be taken into account before comparing the perturbative beta function coefficients and the coefficients of the strong-field limit of the effective Lagrangian. At one-loop this is familiar from instanton physics, but we find that at two-loop the role of the zero modes, and the interplay between IR and UV effects in the renormalization, is quite different. Our analysis is motivated in part by the remarkable simplicity of the two-loop QED effective Lagrangians for a self-dual constant background, and we also present here a new independent derivation of these two-loop results.Comment: 15 pages, revtex

    ПАТОГЕНЕТИЧЕСКИЕ АСПЕКТЫ ВЗАИМОСВЯЗИ ИНФЕКЦИОННЫХ ЗАБОЛЕВАНИЙ РОТОВОЙ ПОЛОСТИ С РАЗВИТИЕМ И ПРОГРЕССИРОВАНИЕМ АТЕРОСКЛЕРОЗА И ВОЗМОЖНОСТИ ИХ КОМПЛЕКСНОЙ ПРОФИЛАКТИКИ

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    The article contains the modern literature data about impact of various infectious agents on the development and progression of atherosclerotic disease. The data are demonstrated the role of various infectious diseases, including periodontal diseases, in the development of biological degradation and destabilization of atherosclerotic plaques. The article questions of organization of primary prevention of cardiovascular disease based on the screening assessment by stomatologist the oral sanitary status. Necessary to carry out sanitation of chronic infection foci of the mouth on the basis of existing children’s health centers. The children’s health centers have a set of dental equipment, with which can perform a screening diagnosis of dental caries, periodontal diseases, non-carious lesions, diseases of the mucous membranes, and conduct preventive oral sanitation. The duties of dental hygienists is teaching children of different age groups to the rules of oral care, demonstration of skills, brushing teeth, information about the importance of prevention of dental caries and periodontal disease, as it is not only important for the preservation of the teeth, but also may prevent the development of ardiovasculardisease adulthood.В статье приводится обзор современной литературы о влиянии различных инфекционных агентов на развитие и прогрессирование атеросклероза. В частности, приводятся данные о роли некоторых возбудителей заболеваний периодонта в деструкции и дестабилизации капсулы атеросклеротических бляшек. Рассматриваются вопросы организации первичной профилактики сердечно-сосудистых заболеваний, основанной на скрининговой оценке гигиенического состояния полости рта и своевременной санации очагов инфекции на базе действующих детских центров здоровья. Детские центры здоровья оснащены комплектом стоматологического оборудования, что позволяет в режиме скринингового тестирования осуществлять диагностику кариеса зубов, болезней пародонта, некариозных поражений, болезней слизистой оболочки и проводить превентивную санацию ротовой полости. В обязанности стоматолога-гигиениста входит обучение детей разных возрастных групп правилам ухода за полостью рта, демонстрация навыков чистки зубов, информирование о важности профилактики кариеса зубов и заболеваний пародонта, так как это имеет не только важное значение для сохранения зубов, но и может предотвратить развитие сердечно-сосудистых заболеваний во взрослом возрасте
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