Gyrotropy and Anisotropy of Rocks: Similarities and Differences

The main features of wave propagation in gyrotropic media are compared with wave propagation in anisotropic media. The results of numerical modelling are presented for three typical seismic exploration models. The first two models are azimuthally anisotropic media (of orthorombic symmetry system, group 2m) without and with gyration. The third model is a gyrotropic transversely isotropic medium with a vertical symmetry axis. The computations have been made for propagation of shear waves along the vertical symmetry axis. For sufficiently short wave paths (in our models less than 400 m) the two-component (x, y) seismograms are similar for all three models. For longer paths both signal shape and signal duration for the first and the third model differ noticeably. Some evidence (experimental data and a micromodel) is given to show that the gyrotropy of rocks does exist or, at least, can exist

Pretreatment of Wastewater from Licorice Processing—A Preliminary Evaluation

This study was performed as a preliminary investigation of anaerobic digestion and the activated sludge process as pretreatment options for highly loaded wastewater from licorice processing (approximately 8000 mg COD/L). Only 15% reduction of initial chemical oxygen demand (COD) was achieved by anaerobic digestion, whereas up to 80% reduction was attained with activated sludge process. Adsorption using powdered activated carbon (PAC) was studied for the removal of color and residual organics from the effluent of aerobic treatment. The combination of aerobic biological treatment with activated carbon adsorption offers a high-quality effluent, however only at very high carbon dosage (>2 kg PAC/m3)

Clinical features of post-COVID period. Results of an International Register "Dynamics Analysis of Comorbidities in SARS-CoV-2 Survivors (ACTIV SARS-CoV-2)" (12-month follow-up)

Aim. To investigate on post-COVID period in patients of the Eurasian region.Material and methods. A total of 9364 consecutively hospitalized patients were included in ACTIV registry. Enrollment of patients began on June 29, 2020, and was completed on March 30, 2021, corresponding to the first and second waves of the pandemic. Demographic, clinical, and laboratory data, computed tomography (CT) results, information about inhospital clinical course and complications of COVID-19 during hospitalization were extracted from electronic health records using a standardized data collection form. The design included follow-up telephone interviews with a standard questionnaire at 3, 6, and 12 months to examine the course of post-COVID period.Results. According to ACTIV register, 63% of patients after COVID-19 had new adverse symptoms or exacerbations of the existing symptoms lasting for up to 1 year. After hospital discharge, 79,8% of patients sought unscheduled medical attention in the first 3 months, 79,1% at 4-6 months, and 64,8% at 7-12 months. Readmission rate was 11,8% in the first 3 months, 10,9% at 4-6 months, and 10,1% at 7-12 months. The most common reasons for unscheduled treatment in the first 3 months were uncontrolled hypertension, decompensated type 2 diabetes, destabilization of coronary artery disease, gastrointestinal disease, AF episodes, exacerbation of asthma and chronic obstructive pulmonary disease, decompensated heart failure (HF). The 12-month mortality of COVID-19 survivors after the discharge was 3,08%. Multivariate analysis showed that independent risk factors for fatal outcome were age (direct correlation), the levels of hemoglobin (inverse correlation), oxygen saturation (inverse correlation), and aspartate aminotransferase (direct correlation), as well as class III-IV HF, prior stroke, cancer, inhospital acute kidney injury. Based on these identified risk factors, a nomogram was constructed to determine the 3-month mortality risk after discharge.Conclusion. Analysis of ACTIV register showed that end of the acute phase of COVID-19 does not imply a complete recovery

Lipid profile in hospitalized patients with COVID-19 depending on the outcome of its acute phase: data from the international registry "Dynamics analysis of comorbidities in SARS-CoV-2 infection survivors"

Aim. To study the lipid profile in hospitalized patients with coronavirus disease 2019 (COVID-19) depending on the outcome of its acute phase according to the AKTIV international registry.Material and methods. The AKTIV registry included men and women over 18 years of age with a diagnosis of COVID-19, who were treated in a hospital. A total of 9364 patients were included in the registry, of which 623 patients were analyzed for levels of total cholesterol, low-density lipoprotein cholesterol (LDL-C) and triglycerides on days 1-2 of hospitalization. The level of high-density lipoprotein cholesterol (HDL-C) was calculated using the Friedewald equation.Results. We found that a decrease in LDL-C level was significantly associated with an unfavorable prognosis for hospitalized patients with COVID-19. This pattern persisted in both univariate and multivariate analyses. LDL-C levels in the final multivariate model had a significant relationship with the prognosis (an increase in the death risk by 1,7 times with a decrease per 1 mmol/l). In addition, we found that the survival of patients with an indicator level of <2,45 mmol/l is significantly worse than in patients with an LDL-C level ≥2,45 mmol/l. All patients with high LDL-C ((≥4,9 mmol/l) survived, while among patients with low LDL-C (<2,45 mmol/l. All patients with high LDL-C ((≥4,9 mmol/l) survived, while among patients with low LDL-C (<1,4 mmol/l), mortality was 13,04%, which was significantly higher than in patients with LDL-C ≥1,4 mmol/l (6,32%, p=0,047).Conclusion. A decrease in LDL-C in the acute period is significantly associated with an unfavorable prognosis for hospitalized patients with COVID-19. Determination of LDL-C can be included in the examination program for patients with COVID-19. However, the predictive value of this parameter requires further study in prospective clinical studies