3,180 research outputs found
Clinical mimics and diagnostic challenges in tick-borne borreliosis: a systematic review
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
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
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
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 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 and on the microscopic parameters of the interaction
potential are studied for the cases and . 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
Kinetic-Ballooning-Limited Pedestals in Spherical Tokamak Plasmas
A theoretical model is presented that for the first time matches experimental
measurements of the pedestal width-height Diallo scaling in the
low-aspect-ratio high- tokamak NSTX. Combining linear gyrokinetics with
self-consistent pedestal equilibrium variation, kinetic-ballooning, rather than
ideal-ballooning plasma instability, is shown to limit achievable confinement
in spherical tokamak pedestals. Simulations are used to find the novel
Gyrokinetic Critical Pedestal constraint, which determines the steepest
pressure profile a pedestal can sustain subject to gyrokinetic instability.
Gyrokinetic width-height scaling expressions for NSTX pedestals with varying
density and temperature profiles are obtained. These scalings for spherical
tokamaks depart significantly from that of conventional aspect ratio tokamaks.Comment: 7 pages, 5 figures. Nuclear Fusion 202
Disorder-Induced Critical Phenomena in Hysteresis: Numerical Scaling in Three and Higher Dimensions
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
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
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
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
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
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