IMMUNOFLUORESCENT STUDY OF ACUTE RESPIRATORY DISEASES (ARD) SPREADED AMONG THE POPULATION OF VARNA AND DEVNYA DURING THE PERIOD SEPTEMBER 1980 - MARCH 1981

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JMMUNOFLUORESCENT DIAGNOSIS OF INFLUENZA INFECTIONS

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Study of Natural Aronia Melanocarpa Fruit Juice for Antibacterial and Antiviral Activity

Natural Aronia melanocarpa fruit juice (AMFJ) is rich in polyphenols most of which are anthocyanins. These compounds and other natural plant products are recently evaluated for their anti-infectious activity. The aim of the present study was to investigate the antibacterial and antiviral activity of AMFJ. AMFJ bacteriostatic activity on referent strains of S. aureus ATCC 25923, E. coli ATCC 25922 and P. aeruginosa ATCC 27853 was assessed by counting the number of colonies after 24h incubation at 37°C using the microbial number method. AMFJ was not bacteriostatic for P. aeruginosa. The microbial number for E. coli was 0 ,3 6xl02 CFU/ml AMFJ and for N. aureus 0,87x10s CFU/ml AMFJ. Gram-positive bacteria should mainly be used as a test for further investigation of the bacteriostatic activity of AMFJ. AMFJ antiviral activity directed to the reproduction in ovo of influenza virus type A (H3N2) was investigated. AMFJ inhibited the reproduction of influenza virus in its initial stages, most probably, due to the formation of complex compounds between the virion, on one hand, and the polyphenols, on the other hand, which influenced the adsorption of the influenza virus on the cell surface

SORPTIVE PROPERTIES OF NATURAL MINERAL SORBENT TOWARDS HEPATITIS-B-SURFACE ANTIGEN

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SORPTION OF ADENOVIRUS TYPE 7 AND ECHO-VIRUS TYPE 19 ONTO A NATURAL MINERAL SORBENT

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ETIOLOGICAL AND EPIDEMIOLOGICAL INVESTIGATIONS OF INFLUENZA IN VARNA AND VARNA DISTRICT DURING THE EPIDEMIC WAVE IN 1974—1975

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Silver Flowerlike Structures for Surface-Enhanced Raman Spectroscopy

Micro-and nanoflowers are a class of materials composed of particles with high surface-to-volume ratio. They have been extensively studied in the last decade due to simple preparation protocols and promising applications in biosensing, as drug delivery agents, for water purification, and so on. Flowerlike objects, due to their highly irregular surface, may act also as plasmonic materials, providing resonant coupling between optical waves and surface plasmon excitations. This fact allows us to infer the possibility to use micro-and nanoflowers as effective surface-enhanced Raman scattering (SERS) substrate materials. Here, we report on the design and Raman enhancement properties of silver flowerlike structures, deposited on aluminum surface. A simple and cost-effective fabrication method is described, which leads to SERS substrates of high developed surface area. The morphology of the silver flowers on a nanoscale is characterized by self-organized quasiperiodic stacks of nanosheets, which act as plasmonic cavity resonators. The substrates were tested against rhodamine-6G (R6G) water solutions of concentration varying between 10−3 M and 10−7 M. Optimal SERS enhancement factors of up to 105 were established at R6G concentrations in the 10−6–10−7 M range. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.This research was funded by the Bulgarian-Russian bilateral project through the contracts KP-06-15/27.09.2019 Russia with the Bulgarian National Fund of Scientific Research (G.G.T, N.D.T., S.C.R., and V.G.I.) and RFBR project No. 19-52-18008 Bulg (A.V.L.)

Variable Stars in Galactic Globular Clusters

Based on a search of the literature up to May 2001, the number of known variable stars in Galactic globular clusters is approximately 3000. Of these, more than 2200 have known periods and the majority (approximately 1800) are of the RR Lyrae type. In addition to the RR Lyrae population, there are approximately 100 eclipsing binaries, 120 SX Phe variables, 60 Cepheids (including population II Cepheids, anomalous Cepheids and RV Tauri) and 120 SR/red variables. The mean period of the fundamental mode RR Lyrae variables is 0.585, for the overtone variables it is 0.342 (0.349 for the first-overtone pulsators and 0.296 for the second-overtone pulsators) and approximately 30% are overtone pulsators. These numbers indicate that about 65% of RR Lyrae variables in Galactic globular clusters belong to Oosterhoff type I systems. The mean period of the RR Lyrae variables in the Oosterhoff type I clusters seems to be correlated with metal abundance in the sense that the periods are longer in the more metal poor clusters. Such a correlation does not exist for the Oosterhoff type II clusters. Most of the Cepheids are in clusters with blue horizontal branches.Comment: 45 pages, 10 figures, to be published in AJ November 200

Chronic Liver Diseases and Parenterally Transmitted Hepatitis Viruses

Hepatitis B virus (HBV), hepatitis C virus (HCV) and hepatitis D virus (HDV) are the leading cause of chronic liver diseases. The aims of the present study are to determine the etiological relationship of HBV and HCV in patients with chronic liver disease in North-Eastern Bulgaria and prevalence of dual and triple infections. A total of 434 patients were investigated for HBsAg, 402 of whom were also tested for anti-HCV. The HBsAg positive subjects were tested for anti-HDV and 32 of them also for HbeAg/anti-Hbe. Separated commercial ELISA kits were used. HBsAg was detected in 132 (30.4%); 10.6% were co-infected with HDV. Anti-HCV was detected in 15.4%. Five of 132 HbsAg positive patients (3.78%) were simultaneously HBV and HCV positive. Two patients out of 132 (1.52%) were positive to HBV, HCV and HDV. Our data indicate that HBV infection was the main cause of chronic liver diseases in North-Eastern Bulgaria, and 10.6% of the patients suffered from severe disease because of co-infection with HDV. HCV plays the same role in 15.4% of the cases. Recently, we observed dually infected (HBV and HCV) and triple infected (HBV, HCV, HDV) patients suffering from severe chronic liver diseases

HEPATITIS B VIRUS VACCINE RESPONSE IN CHILDREN 15-19 YEARS OLD

ABSTRACT To determine Hepatitis B virus vaccine response in vaccinated children 15 -19 years old. Three hundred children were vaccinated after an informed consent and after tests for Hepatitis B virus (HBV) markers (HBsAg, anti-HBc and anti-HBs) during 1999 -2000 in program INTERREG II of European Community (EC). All of them were negative before vaccination. The children were vaccinated by the classic (months 0, 1 and 6) schedule (XI, XII 1999 -V 200