Bulk ferroelectric composite ceramics based on mixtures of BaTiO
3
/SrTiO
3
powders with Mg-containing additives such as Mg
2
TiO
4
, MgO in a wide range of compositions were fabricated and ...characterized. Phase relations, crystal structures, microstructures and dielectric properties of ferroelectrics were investigated. The best composition with respect to the overall combination of dielectric permittivity, tunability and loss factor was found to have ϵ = 103, tanδ ≤ 0.002 at f = 3.5 GHz and tunability 5-6% at a 15 kV/cm biasing field. This combination of electrical parameters makes these materials among the most promising candidates for the development of high power tunable components.
Collider searches for dark sectors, new particles interacting only feebly with ordinary matter, have largely focused on identifying signatures of new mediators, leaving much of dark sector structures ...unexplored. In particular, the existence of dark matter bound states (darkonia) remains to be investigated. This possibility could arise in a simple model in which a dark photon (A^{'}) is light enough to generate an attractive force between dark fermions. We report herein a search for a J^{PC}=1^{--} darkonium state, the ϒ_{D}, produced in the reaction e^{+}e^{-}→γϒ_{D}, ϒ_{D}→A^{'}A^{'}A^{'}, where the dark photons subsequently decay into pairs of leptons or pions, using 514 fb^{-1} of data collected with the BABAR detector. No significant signal is observed, and we set bounds on the γ-A^{'} kinetic mixing as a function of the dark sector coupling constant for 0.001<m_{A^{'}}<3.16 GeV and 0.05<m_{ϒ_{D}}<9.5 GeV.
The paper discusses the effect of a series of focused high-intensity ultrasound pulses from a multi-element transducer on the biological tissue. The simulation of the ultrasound intensity field in a ...homogeneous medium uses the Rayleigh integral. The thermal problem modelling is based on the numerical solution of the heat equation. The advantages of processing a given volume of tissue with pulses, whose focal points over time consistently diverge from the geometric focus of the transducer, have been demonstrated. The effect of the time delay between pulses on the nature of tissue heating and the size of the thermal ablation region is analyzed. The issues of scaling for the problem of heat distribution are discussed.
The aim of the study was to study the clinical and laboratory features of acute respiratory viral infections in hospitalized children.The analysis of medical records of 623 patients admitted to the ...clinic, aged from 1 month to 16 years 11 months 29 days, was carried out. All patients were diagnosed with ARVI on the basis of clinical symptoms with laboratory confirmation in the study of naso- or oropharyngeal smears by PCR.Three groups of children were identified: with respiratory syncytial (RSV) — 384 children (61,6%), metapneumovirus — 142 (22,8%) and bocavirus — 97 (15,6%) infections. It has been established that in the general structure of acute respiratory viral infections in hospitalized children, RSV and rhinovirus are the leading pathogens — 28,8—48,6% and 22,1—41,3%, respectively, depending on the calendar year. The main clinical form was acute bronchitis in 80,5% of cases of confirmed infection, with RS-viral etiology in 79,5% (n = 287) of cases, with metapneumo- and bocavirus infections in 85,6% (n = 95) and 77,8% (n = 56) of children, respectively. Bronchiolitis was characteristic of RSV infection in 10,5% of cases (n = 38). From 10 to 19,4% of cases, the course of these viral infections was complicated by the development of pneumonia.
The CMD-3 detector has begun to take data at the electron-positron collider VEPP-2000 since december 2010. The collected data sample corresponds to an integrated luminosity of 60 pb−1 in the c.m. ...energy range from 0.32 up to 2 GeV and about 50pb−1 for RUN2017. The integrated luminosity was measured by counting e+e− e+e− and e+e− γγ events, allowing additional photons in the final state. Preliminary results of the luminosity measurement are presented for various energy ranges and its accuracy is estimated to be 1%.
Purpose: to study the clinical and etiological features of pneumonia in children with a poor outcome of infectious diseases.
Materials and methods. The retrospective analysis of clinical, anamnestic, ...laboratory, instrumental data of 46 children who died from infectious diseases during the period from December 2009 to November 2019 was carried out, of which 26 patients had pneumonia at autopsy. The etiology of pneumonia was determined in vivo and postmortem using cultural, molecular genetic, serological methods and immunohistocytochemical examination of lung tissue. Pneumonia was classified into primary and secondary.
Results. In patients with pneumonia in the structure of generalized infections (n=26) secondary forms prevailed (septic – 14 cases, ventilator-associated (VAP) – 5, aspiration – 2); primary pneumonia was detected in 5 children. Clinical polymorphism and frequent absence of typical symptoms of pneumonia (cough, shortness of breath, auscultatory and percussion changes) were shown, that led to intravital underdiagnosis of pneumonia in 31% of patients. The probable etiology of pneumonia was detected in vivo and postmortem in 58% and 98% of cases respectively. S. pneumoniae (40%) and H. influenzae type b (40%) were main pathogens in primary pneumonia, N. meningitidis (36%) and S. pneumoniae (29%) – in septic pneumonia, commensals of naso- and oropharynx (S. salivarius) – in aspiration pneumonia, nosocomial bacteria (S. aureus and coagulase-negative staphylococci) – in VAP. In children with HIV infection, pneumonia was associated with opportunistic pathogens (P. jirovecii, C. neoformans). In 87% of cases polymicrobial associations were found in lower airways, that makes it difficult to identify the main causative agent of pneumonia.
Conclusions. Most of symptoms of pediatric pneumonia in the structure of generalized infections are nonspecific. Post-mortem study improves the etiological verification of pneumonia and allow to suggest the most pathogenetically and thanatogenetically significant pathogen.
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