Self-induced and induced transparencies of two-dimensional and three- dimensional superlattices

The phenomenon of transparency in two-dimensional and three-dimensional superlattices is analyzed on the basis of the Boltzmann equation with a collision term encompassing three distinct scattering mechanisms (elastic, inelastic and electron-electron) in terms of three corresponding distinct relaxation times. On this basis, we show that electron heating in the plane perpendicular to the current direction drastically changes the conditions for the occurrence of self-induced transparency in the superlattice. In particular, it leads to an additional modulation of the current amplitudes excited by an applied biharmonic electric field with harmonic components polarized in orthogonal directions. Furthermore, we show that self-induced transparency and dynamic localization are different phenomena with different physical origins, displaced in time from each other, and, in general, they arise at different electric fields.Comment: to appear in Physical Review

The Relationship Between Indicators of Nasal Respiratory Function and Spirometric Parameters in Children With Bronchial Asthma

Introduction: The relationship between objective indicators of nasal obstruction and airflow limitation in children with bronchial asthma (BA) and allergic rhinitis (AR) has not yet been studied. Objective: To study the relationship between objective parameters of nasal obstruction and airflow limitation, determined using the methods of anterior active rhinomanometry (AARM) and spirometry in children with BA and AR. Materials and Methods: Eighty eight children and adolescents with BA and AR, boys−65.9% (58/88), were examined. The median age was 11.09 [10.42; 11.76] years. To determine airflow limitation, the following spirometric parameters were evaluated: forced vital capacity of the lungs (FVC), forced expiratory volume in 1 s (FEV1), the ratio of FEV1/FVC, and maximum expiratory flow at the point 25% of the flow-volume loop (MEF25). Data were recorded both in absolute values and in relative units (% pred). Nasal respiratory function was determined by AARM based on the total nasal airflow (TNAF) in absolute (Pa/cm3/s) and relative units (RTNAF, % pred). Results: In the general cohort and in boys but not in girls, a statistically significant direct correlation was found between TNAF (Pa/cm3/s) and absolute spirometry parameters of bronchial patency—all had p 0.05. Additional analysis of literature was conducted to ascertain that the identified gender differences were not occasional. Conclusion: The significant positive correlation of absolute values of AARM and spirometric parameters in children with BA and AR was established, which apparently reflects the physical development of children. Of all the relative indicators of spirometry, only MEF25 (% pred), which indirectly reflects the patency of small bronchi, had a distinct direct correlation with RTNAF. These patterns are clearly expressed in boys with BA. In girls with this disease, however, the relationship between nasal respiratory function and spirometric indicators seems to be more complex and requires further study

The effect of nasal microbiota on the level of total immunoglobulin e in blood serum of children with bronchial asthma

Objective of the research: to study the relationship between the level of total IgE in serum and the nature of the nasal microbiota composition in children with bronchial asthma (BA). Materials and methods: 332 patients with BA were examined, mean age 10,34±0,4 years, 72% boys (239/332), the levels of total IgE and IgA, IgM, IgG in blood serum were determined, the composition of the nasal microbiota was studied by culture method. Results: 21,7% (72/332) of children had no St. aureus and St. epidermidis and other conditionally pathogenic flora in nasal microbiota; in 74,1% (246/332) of children S. aureus or St. epidermidis was revealed, in 40,7% (135/332) of them St. aureus was isolated; in 4,2% (14/332) another conditionally pathogenic microflora was found. The level of total IgE in blood serum in patients who had St. aureus in nasal microbiota was the highest and amounted to 218 [172,5; 264,3] IU/ml (p=0,002). Conclusion: St. aureus on the nasal mucosa of the upper respiratory tract in children with BA is accompanied by a higher level of total IgE in blood serum. © 2020, Pediatria Ltd.. All rights reserved

The Relationship Between Bronchial Patency and Parameters of ECG Supraventricular Component in Children With Bronchial Asthma

© Copyright © 2020 Gordina, Egoshina, Eliseeva, Vinogradova, Ovsyannikov, Tush, Prakhov, Daniel-Abu, Khaletskaya and Kubysheva. Background: Uncontrolled asthma (BA) can be complicated by cardiac conduction disturbances and arrhythmias. It is typical mainly for adult asthmatics patients. In asthmatics children the effect of bronchoconstriction on cardiac conduction, including the supraventricular component of the ECG, is currently under discussion. The objective of the research is to analyze ECG parameters of the atrial complex and atrioventricular conduction and to assess their relationship with spirometric indicators in children with BA. Methods: Hundred three patients with BA from the age of 6–17 years were examined. The spirometric parameters were evaluated, including the Tiffeneau index (TI): FEV1/FVC (%), according to the level of which the patient groups were distinguished. Group 1 (G1): with TI more than 85%, (n = 15); Group 2 (G2): with TI from 85 to 75%, (n = 40); Group 3 (G3): with TI <75%, (n = 48). The ECG parameters that characterize supraventricular conduction, including the PQ interval (sec) and the sPQ segment (sec), were analyzed. We had calculated relative PQ (rPQ) by the formula rPQ=PQ/PQmed, where PQ is the patient's PQ, PQmed are the median PQ values of healthy children of age selected. Results: The duration of the PQ in groups G1 and G2 was 0.13 (0.11; 0.14) s; and 0.13 (0.12; 0.14) s, respectively, which is statistically significantly less than in patients of groups G3–0.14 (0.13; 0.15] s, p = 0.01. The duration of the sPQ segment in children of groups G1 and G2 was also generally shorter than in patients of groups G3, and amounted, respectively, to 0.05 (0.04; 0.06) s, 0.04 (0.04; 0.05) s, and 0.06 (0.04; 0.07) s, p = 0.02. The rPQ increased progressively as TI decreased and amounted in G1 to 92.9 (85.7; 106.3) %, in G2 100.0 (92.9; 103.0) %, and in G3 104 (100.0; 107.7) %, p = 0.009. A statistically significant negative correlation between IT and PQ–r = −0.23, p = 0.02; with sPQ–r = −0.20, p = 0.045; and with rPQ–r = −0.25, p = 0.01 was revealed. Conclusion: A decrease in TI in asthmatics children is associated with a prolongation of the PQ. This may indicate a slowdown in supraventricular conduction in patients with uncontrolled asthma and, thus, be considered as a risk for the formation of subsequent supraventricular arrhythmias

The Relationship Between Indicators of Nasal Respiratory Function and Spirometric Parameters in Children With Bronchial Asthma

Introduction: The relationship between objective indicators of nasal obstruction and airflow limitation in children with bronchial asthma (BA) and allergic rhinitis (AR) has not yet been studied. Objective: To study the relationship between objective parameters of nasal obstruction and airflow limitation, determined using the methods of anterior active rhinomanometry (AARM) and spirometry in children with BA and AR. Materials and Methods: Eighty eight children and adolescents with BA and AR, boys−65.9% (58/88), were examined. The median age was 11.09 [10.42; 11.76] years. To determine airflow limitation, the following spirometric parameters were evaluated: forced vital capacity of the lungs (FVC), forced expiratory volume in 1 s (FEV1), the ratio of FEV1/FVC, and maximum expiratory flow at the point 25% of the flow-volume loop (MEF25). Data were recorded both in absolute values and in relative units (% pred). Nasal respiratory function was determined by AARM based on the total nasal airflow (TNAF) in absolute (Pa/cm3/s) and relative units (RTNAF, % pred). Results: In the general cohort and in boys but not in girls, a statistically significant direct correlation was found between TNAF (Pa/cm3/s) and absolute spirometry parameters of bronchial patency—all had p &lt; 0.01. Also, RTNAF and relative MEF25 values (% pred) in the general cohort were R = 0.22, p = 0.04, and in boys, R = 0.28, p = 0.03. In girls, there was no statistically significant correlation between nasal respiratory function and spirometric parameters, all p &gt; 0.05. Additional analysis of literature was conducted to ascertain that the identified gender differences were not occasional. Conclusion: The significant positive correlation of absolute values of AARM and spirometric parameters in children with BA and AR was established, which apparently reflects the physical development of children. Of all the relative indicators of spirometry, only MEF25 (% pred), which indirectly reflects the patency of small bronchi, had a distinct direct correlation with RTNAF. These patterns are clearly expressed in boys with BA. In girls with this disease, however, the relationship between nasal respiratory function and spirometric indicators seems to be more complex and requires further study. © Copyright © 2021 Krasilnikova, Khramov, Khramova, Ovsyannikov, Daniel-Abu, Novozhilov, Shahov, Kubysheva and Eliseeva

The Relationship Between Bronchial Patency and Parameters of ECG Supraventricular Component in Children With Bronchial Asthma

Background: Uncontrolled asthma (BA) can be complicated by cardiac conduction disturbances and arrhythmias. It is typical mainly for adult asthmatics patients. In asthmatics children the effect of bronchoconstriction on cardiac conduction, including the supraventricular component of the ECG, is currently under discussion. The objective of the research is to analyze ECG parameters of the atrial complex and atrioventricular conduction and to assess their relationship with spirometric indicators in children with BA. Methods: Hundred three patients with BA from the age of 6–17 years were examined. The spirometric parameters were evaluated, including the Tiffeneau index (TI): FEV1/FVC (%), according to the level of which the patient groups were distinguished. Group 1 (G1): with TI more than 85%, (n = 15); Group 2 (G2): with TI from 85 to 75%, (n = 40); Group 3 (G3): with TI <75%, (n = 48). The ECG parameters that characterize supraventricular conduction, including the PQ interval (sec) and the sPQ segment (sec), were analyzed. We had calculated relative PQ (rPQ) by the formula rPQ=PQ/PQmed, where PQ is the patient's PQ, PQmed are the median PQ values of healthy children of age selected. Results: The duration of the PQ in groups G1 and G2 was 0.13 (0.11; 0.14) s; and 0.13 (0.12; 0.14) s, respectively, which is statistically significantly less than in patients of groups G3–0.14 (0.13; 0.15] s, p = 0.01. The duration of the sPQ segment in children of groups G1 and G2 was also generally shorter than in patients of groups G3, and amounted, respectively, to 0.05 (0.04; 0.06) s, 0.04 (0.04; 0.05) s, and 0.06 (0.04; 0.07) s, p = 0.02. The rPQ increased progressively as TI decreased and amounted in G1 to 92.9 (85.7; 106.3) %, in G2 100.0 (92.9; 103.0) %, and in G3 104 (100.0; 107.7) %, p = 0.009. A statistically significant negative correlation between IT and PQ–r = −0.23, p = 0.02; with sPQ–r = −0.20, p = 0.045; and with rPQ–r = −0.25, p = 0.01 was revealed. Conclusion: A decrease in TI in asthmatics children is associated with a prolongation of the PQ. This may indicate a slowdown in supraventricular conduction in patients with uncontrolled asthma and, thus, be considered as a risk for the formation of subsequent supraventricular arrhythmias. © Copyright © 2020 Gordina, Egoshina, Eliseeva, Vinogradova, Ovsyannikov, Tush, Prakhov, Daniel-Abu, Khaletskaya and Kubysheva

POSSIBILITIES OF EARLY DIAGNOSIS OF PRIMARY CILIARY DYSKINESIA

Despite the manifestations of primary ciliary dyskinesia (PCD) in the neonatal period or in the first year of life, the diagnosis of this rare disease is usually established at the age of 4–7 years. The aim of the study was to search for reserves for early diagnosis of PCD. Materials and methods of research: 17 patients were observed with PCD, confirmed on the basis of the PICADAR scale, high-speed light video microscopy (all patients) and transmission electron microscopy (in 3 patients) of the mucous biopsy of the respiratory membrane using a genetic study (in one patient). Results: all patients were born full-term; neonatal respiratory distress syndrome (RDS) was observed in 71% of patients; the median duration of mechanical ventilation/oxygen therapy was 14 [7; 21] days; lateralization abnormalities were found in 35% of patients; all patients had persistent nasal congestion and/or rhinorrhea, 94% had chronic or recurrent sinusitis, otitis, recurrent pneumonia, chest x-ray and computed tomography (CT) scans in 71% had atelectasis with constant localization in the middle lobe, 12 of 15 patients, traced in the follow-up, – bronchiectasis (BE), also mainly in the middle lobe (in 9 patients). The average age at diagnosis was 5 [1.75; 7] years, patients with an established diagnosis over the age of 3 years were more often diagnosed with BE. The median of PICADAR scores was 7 [6; 8] points. Conclusions: to establish early diagnosis of PCD, it is important to consider neonatal RDS, lateralization of organs, difficulty in nasal breathing, starting from the first half of life. © 2022, Pediatria Ltd. All rights reserved