Decay processes of long-lived phonons in 6H-SiC.

Temperature evolution of the high-resolution far-infrared transmission spectra of 6H-SiC single crystal slab is experimentally examined in a temperature range of 5-320 K. Temperature dependences of the phonon lifetimes for long-lived phonons, namely the IR active folded transverse acoustic (FTA) phonon doublet, are determined. These dependences are interpreted in the framework of a theoretical model developed using first principle anharmonic lattice dynamics. It is shown that three-phonon anharmonic processes dominate in the FTA phonon decay at temperatures above 160 K resulting in a rapid decrease of the phonon lifetimes with increasing temperature. Contribution of four-phonon anharmonic processes is negligibly small at temperatures below 320 K.

[Polypragmasia and interdrug interactions as risk factors of falling in elderly patients.]

This article presents the results of the analysis of data from patients over 75 years of age from a multidisciplinary hospital with cardiovascular disease and comorbid conditions. Pharmacotherapy of gerontological patients with multiple risk factors for falls was analysed in terms of the presence of polypragmasy and drug-drug interactions hazardous to the risk of falls. In the group of patients who experienced a fall in hospital compared to patients without a fall, the prescription lists audit showed a predominance of medicines (drugs) and drug combinations compromised by an increased risk of this serious adverse event. An audit of prescriptions of patients at increased risk of falls as a means of combating polypharmacy and identifying drugs that may cause falls can be conducted using the «Traffic light classification of FRIDs¼ and drug checkers to identify clinically relevant combinations. The use of these clinical and pharmacological tools can improve the quality and safety of medical care in a hospital setting.

[Initiation of pharmacotherapy as a risk factor for older patients.]

The article presents the literature and original data on the problems of falls in elderly patients. The connection of the fact of falling with initiation of therapy by a number of drugs known to have a negative impact on the risk of falling is considered. The article presents data on the frequency and structure of falls on the example of patients with cardiovascular diseases older than 75 years, treated in a multidisciplinary hospital. The analysis of the data showed a tendency of prevalence of the fact of falling in 1/3 patients (33,8%) in the first 5 days of hospital stay, which may be associated with high drug burden and the appointment of «new¼ drugs for the patient. The study noted that it was on the first day that the selection of therapy took place and additional drugs were often prescribed, leading to a state of polypragmasia. Analysis of individual groups of drugs was able to reliably confirm the relationship between the appointment of drugs that increase.

Interaction of surface plasmon-phonon polaritons with terahertz radiation in heavily doped GaAs epilayers.

We report on experimental studies of the surface plasmon-phonon polariton excitations in heavily doped GaAs epitaxial layers. Reflection and emission of radiation in the frequency range of 2-19 THz were investigated for samples with surface-relief grating, as well as for samples with planar surface. The reflectivity spectrum for p-polarized radiation measured for the sample with the surface-relief grating demonstrates a set of resonances attributed to excitations of different surface plasmon-phonon polariton modes. The observed resonances lie beyond the limits of the Reststrahlen band. Terahertz radiation emission from the samples was studied in nonequilibrium conditions under the pulsed electric field excitation. Two contributions to the spectral density of the terahertz radiation have been revealed, the first being due to bulk plasmon-phonon polaritons (PPhPs), while the second originating from the surface PPhPs. A field dependence of the effective temperature of the bulk PPhPs has been established. Polarization dependence of the terahertz radiation related to surface PPhPs has been experimentally examined for the first time.

[Diagnostic and prognostic significance of study of acute phase proteins in children with appendicular peritonitis]. / Diagnosticheskoe i prognosticheskoe znachenie issledovaniia belkov ostroi fazy pri appendikuliarnom peritonite u detei.

Acute phase proteins (fibrinogen, alpha 2-macroglobulin, alpha 1-antitrypsin) were measured in 47 patients with destructive appendicitis and 203 children with local (n = 121) and disseminated (n = 82) appendicular peritonitis. The patients' ages varied from 3 to 15 years. Control group consisted of 45 age-matched children with uncomplicated umbilical and inguinal hernias. The significance of acute phase proteins in the diagnosis and preoperative and postoperative treatment planning was evaluated.

[Reversible aggregation of erythrocytes in children with appendicular peritonitis]. / Obratimaia aggregatsiia éritrotsitov pri appendikuliarnom peritonite u detei.

A microtest for quantitative evaluation of the kinetics of reversible aggregation of erythrocytes was used in 47 patients and 203 children with local (121 cases) and diffuse (82 cases) appendicular peritonitis. The patients' ages varied from 3 to 15 years. The diagnosis was confirmed clinically, intraoperatively, and morphologically during examination of removed appendices. The development of appendicular peritonitis of different dissemination was paralleled by pronounced intensification of reversible aggregation of peripheral blood erythrocytes, which suggests high diagnostic and prognostic significance of reversible aggregation of erythrocytes, determines the strategy of preoperative treatment, and helps plan the volume of intervention.

[The activity of trypsin and proteolytic inhibitors in complicated forms of appendicitis in children]. / Aktivnost' tripsina i ingibitorov proteoliza pri oslozhnennykh formakh appenditsita u detei.

The activity of trypsin, alpha 1-proteinase inhibitor, and alpha 2-macroglobulin (MG) was measured in the blood plasma of patients with destructive appendicitis and localized and generalized peritonitis during admission to hospital and for 3 weeks after surgery. A deficit of MG was found in all forms of these diseases. A decreased activity of MG in the blood plasma is apparently a risk factor for emergency inflammatory diseases of abdominal organs. After appendectomy a more demonstrative index of patient's status is trypsin activity, an increase of which is most of all expressed in generalized peritonitis. Quantitative assessment of the trypsin-inhibitor system activity before and after surgery is necessary for a more accurate diagnosis and for monitoring the quality of treatment.