Półsztywne pianki poliuretanowe z poliolem rzepakowym o różnej lepkości

The subject of research presented in this article are the semi-rigid polyurethane foams (SRFPUR) produced with a formula developed by the company FAMPUR. It consisted of replacing the petrochemical polyol with two types of rapeseed oil-based polyols of different viscosity. Foams were characterized using such techniques as infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry. With the use of scanning electron microscope changes in the structure of materials were analyzed. In addition, the apparent density, number of closed cells, and properties of materials during compression tests were determined.Na podstawie receptury opracowanej przez firmę FAMPUR wytworzono półsztywne pianki poliuretanowe (SRFPUR). Poliol petrochemiczny zastąpiono dwoma różniącymi się lepkością typami polioli z oleju rzepakowego. Pianki scharakteryzowano za pomocą spektroskopii w podczerwieni, analizy termograwimetrycznej i różnicowej kalorymetrii skaningowej. Zmiany struktury materiałów badano metodą mikroskopii skaningowej. Oznaczono też gęstość pozorną, liczbę komórek zamkniętych oraz właściwości wytworzonych pianek w próbie ściskania

Antimicrobial resistance and genotypes of staphylococci from bovine milk and the cowshed environment

Investigation of antimicrobial resistance and genetic relatedness of staphylococci from milk of cows with mastitis and cowshed environment was the aim of this study. Antimicrobial resistance against 14 antimicrobials were determined by using a disc diffusion method. Genetic similarity between the most frequently isolated species was analysed by PFGE (pulsed-field gel electrophoresis). Haemolytic activity, DNase, protease and esterase production was also investigated. Coagulase-negative Staphylococcus species were isolated from 30.8% of milk samples from cows with mastitis. The most frequently isolated species was Staphylococcus xylosus and yield of these organisms was significantly associated with milk of mastitis cows. S. epidermidis was a predominant penicillin-resistant species. High frequency of resistance to lincomycin was observed among isolates of S. sciuri (54.2%) and S. xylosus (25.9%) from cows with mastitis. PFGE (pulsed-field gel electrophoresis) analysis of 29 Staphylococcus aureus isolates showed the presence of 17 PFGE pulsotypes. Isolates of S. sciuri (n=36) had unique PFGE patterns. Some S. xylosus isolates from milk and milker’s hands had the same PFGE pulsotypes, and this observation could indicate that dairyman may be a potential source of the infection. The pulsotype of each of the remaining isolates of S. xylosus suggested that they might have come from common environmental sources; however, these isolates differed in antibiotic resistance pattern or virulence traits. Therefore, knowledge about antibiotic sensitivity pattern and virulence factors of a CNS isolate, besides its genotype, may be informative in tracking the source of the infection

Tannic acid-modified silver nanoparticles for wound healing: the importance of size

Piotr Orlowski,1 Magdalena Zmigrodzka,2 Emilia Tomaszewska,3 Katarzyna Ranoszek-Soliwoda,3 Monika Czupryn,1 Malgorzata Antos-Bielska,1 Janusz Szemraj,4 Grzegorz Celichowski,3 Jaroslaw Grobelny,3 Malgorzata Krzyzowska1 1Military Institute of Hygiene and Epidemiology, Warsaw, Poland; 2Department of Pathology and Veterinary Diagnostics, Faculty of Veterinary Medicine, Warsaw University of Life Sciences (WULS-SGGW), Warsaw, Poland; 3Department of Materials Technology and Chemistry, Faculty of Chemistry, University of Lodz, Lodz, Poland; 4Bionanopark, Lodz, Poland Introduction: Silver nanoparticles (AgNPs) have been shown to promote wound healing and to exhibit antimicrobial properties against a broad range of bacteria. In our previous study, we prepared tannic acid (TA)-modified AgNPs showing a good toxicological profile and immunomodulatory properties useful for potential dermal applications.Methods: In this study, in vitro scratch assay, antimicrobial tests, modified lymph node assay as well as a mouse splint wound model were used to access the wound healing potential of TA-modified and unmodified AgNPs.Results: TA-modified but not unmodified AgNPs exhibited effective antibacterial activity against Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli and stimulated migration of keratinocytes in vitro. The tests using the mouse splint wound model showed that TA-modified 33 and 46 nm AgNPs promoted better wound closure, epithelialization, angiogenesis and formation of the granulation tissue. Additionally, AgNPs elicited expression of VEGF-α, PDGF-β and TGF-β1 cytokines involved in wound healing more efficiently in comparison to control and TA-treated wounds. However, both the lymph node assay and the wound model showed that TA-modified AgNPs sized 13 nm can elicit strong inflammatory response not only during wound healing but also when applied to the damaged skin.Conclusion: TA-modified AgNPs sized >26 nm promote wound healing better than TA-modified or unmodified AgNPs. These findings suggest that TA-modified AgNPs sized >26 nm may have a promising application in wound management. Keywords: hydrolyzable tannin, split wound, silver, antimicrobials, inflammation, fibroblasts, monocyte