Epoxy Composites with Post-Production Gray Cast-Iron Powders.

Processing of cast-iron castings by machining is associated with a large amount of post-production waste in the form of cast-iron chips, which constitute up to about 5% of the weight of the entire casting. In the case of serial production, this generates large amounts of post-production waste, constituting a constantly growing scale of environmental problems. The aim of this research was to develop a simple and cheap method of utilizing post-production waste of gray cast-iron chips from the machining process for the production of small structural elements of water supply fittings. The analysis of the state of knowledge indicates that the simplest method of managing waste chips is to use them as a starting material in the process of manufacturing polymer composites. The most frequently chosen material for the matrix of polymer composites reinforced with metal powders is epoxy resin. The epoxy composite was produced by the vacuum-assisted casting method. This paper presents the results of tests of morphological, mechanical, and corrosion properties of epoxy composites filled with grey cast-iron powder with a grain size below 0.075 mm and a mass content in the composite of 65%. The composite cured at 130 °C for 90 min had the best mechanical properties. The sample cured at 130 °C for 90 min was observed to have the optimum effect, with a tensile strength of 28.35 MPa, a flexural strength of 55.4 MPa, and a compressive strength of 53.8 MPa. All tested composites were characterized by very good thermal resistance and, in comparison to gray cast iron, over 2.5 times lower weight and an over three times lower corrosion rate in the tap water environment.

Theromyzon maculosum (Rathke, 1862) as a vector of potentially pathogenic fungi in aquatic ecosystems.

The aim of the study was to check the integument and alimentary tract of Theromyzon for the occurrence of fungi. Moreover, the mycological purity of water sources from which leeches were collected was analyzed. The potential role of the duck leech Theromyzon maculosum in transmitting pathogenic fungi has not been studied until now. Mycological analyses were performed according to the procedure approved in mycological diagnostic laboratories, using classical diagnostic methods (macro- and microcultures, microscopic observations). In total, 22 species of yeasts were detected. The specimens belong to eight genera: Candida, Citeromyces, Debaryomyces, Kluyveromyces, Lodderomyces, Pichia, Saccharomyces and Saccharomycodes. Overall, 18 species of fungi were isolated from leeches Theromyzon maculosum, including seven species from the integument and 11 species from the gastrointestinal system. Among fungi isolated from body integument, fungi of the genus Candida were dominant, whereas in the gastrointestinal system, the genus Saccharomyces dominated. From the river waters, nine fungi species were isolated, and yeasts of the genera Candida and Kluyveromyces dominated. Isolation of the same species of microfungi from the integument of leeches and the river water suggests that Theromyzon maculosum may be a potential vector of pathogenic yeasts for vertebrates living in the same ecosystems and for humans.

Dishwashers as an Extreme Environment of Potentially Pathogenic Yeast Species.

The study aimed to compare the yeast species diversity in the specific environment of dishwashers, taking into account the potential risk for users. Yeasts were isolated from ten dishwashers and from tap water supplied to the appliances. Samples were collected for mycological analyses at the beginning of each month, from February to May 2016. Four dishwasher sites (rubber seals, detergent dispensers, sprinklers, and water drains) were analyzed. The microfungi were identified by the standard procedures applied in mycological diagnostics. To confirm species identification, molecular analysis was performed based on the sequences of the D1/D2 region. The presence of microfungi was detected in 70% of the investigated appliances. Rubber seals, detergent dispensers, and water drains were the most frequently colonized elements. Thirty-five yeast strains were isolated in this study, of which twenty-seven were obtained from dishwashers and eight from tap water. The strains belonged to six genera and six species (Candida parapsilosis, Clavispora lusitaniae, Dipodascus capitatus, Exophiala dermatitidis, Meyerozyma guilliermondii, and Rhodotorula mucilaginosa). Most of the strains came from rubber seals. In this way, it was demonstrated that the dishwashers' condition is sufficient as an ecological niche for microfungi.

Influence of Elemental Carbon (EC) Coating Covering nc-(Ti,Mo)C Particles on the Microstructure and Properties of Titanium Matrix Composites Prepared by Reactive Spark Plasma Sintering.

This paper describes the microstructure and properties of titanium-based composites obtained as a result of a reactive spark plasma sintering of a mixture of titanium and nanostructured (Ti,Mo)C-type carbide in a carbon shell. Composites with different ceramic addition mass percentage (10 and 20 wt %) were produced. Effect of content of elemental carbon covering nc-(Ti,Mo)C reinforcing phase particles on the microstructure, mechanical, tribological, and corrosion properties of the titanium-based composites was investigated. The microstructural evolution, mechanical properties, and tribological behavior of the Ti + (Ti,Mo)C/C composites were evaluated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), electron backscatter diffraction analysis (EBSD), X-ray photoelectron spectroscopy (XPS), 3D confocal laser scanning microscopy, nanoindentation, and ball-on-disk wear test. Moreover, corrosion resistance in a 3.5 wt % NaCl solution at RT were also investigated. It was found that the carbon content affected the tested properties. With the increase of carbon content from ca. 3 to 40 wt % in the (Ti,Mo)C/C reinforcing phase, an increase in the Young's modulus, hardness, and fracture toughness of spark plasma sintered composites was observed. The results of abrasive and corrosive resistance tests were presented and compared with experimental data obtained for cp-Ti and Ti-6Al-4V alloy without the reinforcing phase. Moreover, it was found that an increase in the percentage of carbon increased the resistance to abrasive wear and to electrochemical corrosion of composites, measured by the relatively lower values of the friction coefficient and volume of wear and higher values of resistance polarization. This resistance results from the fact that a stable of TiO2 layer doped with MoO3 is formed on the surface of the composites. The results of experimental studies on the composites were compared with those obtained for cp-Ti and Ti-6Al-4V alloy without the reinforcing phase.

Sucking of human blood by Placobdella costata (O. F. Müller, 1846) (Hirudinida: Glossiphoniidae): Case study with notes on body form.

Four events of Placobdella costata sucking human blood are described.Human blood was sucked by both adult and juvenile specimens of P. costata.The feeding strategies of juveniles under parental care are presented.New data on juvenile specimens' body form are presented.Information on the potential role of mammals in dispersion and habitat preferences of leeches P. costata is considered.

Phyllosphere of Submerged Plants in Bathing Lakes as a Reservoir of Fungi-Potential Human Pathogens.

This study analysed whether the littoral zone in the immediate vicinity of bathing sites retains potentially pathogenic yeasts on the phyllosphere surface and to what extent the species composition of microfungi in the phyllosphere and in surface waters is similar. The research was carried out in selected lakes located within the administrative boundaries of the city of Olsztyn, the largest city in the Masurian Lake District (NE Poland). The experiment was conducted in three summer seasons near bathing sites in three lakes, which are the most popular as recreational sites (Lake Kortowskie, Lake Tyrsko, and Lake Skanda). Microfungi isolated from the phyllosphere of 13 plant species of the littoral zone from dropped leaves of coast plants with no disease symptoms were used as the study material. The isolated fungi were identified in accordance with the accepted diagnostic procedures applied in mycological laboratories. A total of 36 yeast species of 16 genera were identified. Fungi found earlier at the bathing sites of the lakes were identified in 60% of the cases. Nine species were categorised as class BSL-2 fungi. This study provides a valuable complement of data concerning the natural composition of the littoral microbiota.

Potentially pathogenic fungi of the Candida genus isolated from the Lyna River ­ a 20-year study

This paper concerns part of a monitoring study and contains the results of 20-year observations on the species diversity and dynamics of the count Candida genus fungi which inhabit surface waters. The research material consisted of water samples collected from the Lyna River, the main river of the Warminsko-Mazurskie Voivodeship, within the administrative boundaries of the city of Olsztyn. The samples were subjected to routine diagnostic testing applied in hydromycological studies. The obtained fungi isolates were determined, documented photographically and deposited in a strain collection of the Department of Microbiology and Mycology at the University of Warmia and Mazury in Olsztyn. A total of 23s of the Candida genus were isolated, including six species in the teleomorphic stage. It was noted that over the past decade, the taxonomic diversity of the fungi had increased significantly (from 2 to 23 species). Potential anthropopathogens had also emerged. Over the twenty-year period of observations, the species that were always isolated were Candida albicans and C. guilliermondii, characterised by high pathogenicity and bioindicative properties, which are important in the epidemiology of fungal infections.

Mycological monitoring of selected aquatic ecosystems in the context of epidemiological hazards. Drinking water.

Many species of microfungi are reported in aquatic ecosystems with different frequency. Their number constantly fluctuates depending on the concentration of environmental and anthropogenic factors. Drinking water, tap and bottled, is essential for the proper functioning of the human body. It is also the main component of food and hence it should be safe for human health and free of contaminants. The mycological purity of tap water in two large cities in the region (Olsztyn and Ostroleka) and a small village (Gaglawki) as well as bottled, medium-mineralized and curative water stored under different conditions were tested. The laboratory investigations followed a pathway applied in diagnostic mycological laboratories. The conducted tests demonstrated that microfungi were found in tap water originating from the cities and in bottled water. The rural water supply system was free from contaminations. Eighteen species of microfungi were identified in tap water from Olsztyn and 9 species in tap water from Ostroleka. In bottled water, 13 fungal species were detected. Exophiala spinifera and Debaryomyces hansenii were recorded in the water supply systems of both cities, while one common species, i.e. Aspergillus fumigatus, was identified in tap water fromOstroleka and in bottled water. The conducted studies have significant practical implications, for instance in sanitary and epidemiological water evaluation and in medicine in the context of analysing the quality of drinking water in reference to health resorts and nosocomial infections.

Yeasts isolated from frequently in-patients and out-patients.

The paper is a part of a general mycological monitoring study of nosocomial infections. Differences in the species composition and drug resistance of fungi isolated from in-patients and out-patients prompted an analysis of this topic. The studies were conducted with fungi from the collection of the Department of Mycology, University of Warmia and Mazury in Olsztyn, that were isolated from the oral cavity, sputum, bronchoscopic fluid, anus and skin from 100 in-patients and 100 out-patients. Laboratory analyses, including species categorization of fungi, were performed according to routine mycological diagnostics. Drug sensitivity to fluconazole and nystatin was tested with the disc diffusion method. In the group of in-patients, a wider taxonomic diversity of fungi (12 species) was found in comparison with the out-patients (7 species) and 31 cases of multifocal infections were recorded, while in the second group the number of the latter was only six. In all patients, C. albicans were predominant, constituting the largest proportion in focal infections in all patients and in multifocal infections in the in-patients. In the latter, over a half of the examined individuals were resistant to fluconazole (C. glabrata and C. krusei ­ 80%, C. tropicalis and S. capsularis ­ 60%, C.guilliermondii ­ 50%) and nystatin (T. beigelii ­ 80%, C. krusei and C. tropicalis ­ 50%). Substantially lower drug resistance of fungi was recorded in the out-patients. The hospital environment is an abundant reservoir of different fungal species with significantly greater expansiveness and aggressiveness compared to the environment outside a hospital.

Snow in the city as a spore bank of potentially pathogenic fungi.

This study evaluates the role of snow as a specific ecological niche and a vector in fungal spreading with particular emphasis on potential pathogens in seasonally and daily changing conditions. The experimental material was fungi isolated from the atmospheric air, snow cover, and fragments of ice and soil from underneath the snow cover. The total count of microfungi in the air before snowfall, i.e. in the autumn, reached 1756.1 CFU/m(3) on average. After the first snowfalls, it dropped to 85.2 CFU/m(3). The analyzed samples of snow cover contained from 101.6 to 8500.0 CFU/m(3) of fungi. Furthermore, 26 species of yeast and yeast-like fungi were isolated from the experimental material. Amongst the analyzed species, 13 were potential anthropopathogens. Though another three species were isolated from organ ontocenoses, i.e. Candida intermedia, Saccharomyces bayanus and Zygosaccharomyces rouxii, their pathogenic potential has not yet been explicitly confirmed. The results of the presented study may be applied in predicting concentrations of fungal spores responsible for mycoses. The first snowfalls significantly reduced the number of colony-forming units of fungi in the air. Under conditions of temperate climate, snow becomes a temporary bank of yeast-like fungi spores and while it melts cells of deposited microfungi migrate to the atmosphere. Hence, individuals with impaired immunity or in the course of immunosuppression or recovery should avoid long walks during periods of snow melting. The count of fungi in urban bioaerosol during the melt may be reduced through systematic removal of snow cover, which is a significant reservoir of potential pathogens. In addition, it should be noted that even a typical psychrophilic strain, capable of surviving at a temperature of 37°C, may bear a significant pathogenic potential.

[Moulds isolated from the upper sections of the respiratory and alimentary tracts of healthy veterinary medicine students]. / Grzyby plesniowe izolowane z górnych odcinków ukladu oddechowego i pokarmowego zdrowych studentów medycyny weterynaryjnej.

BACKGROUND: The mycological studies in healthy veterinary medicine students have been prompted by the fact that only a few publications are available to date on the occurrence of moulds in people identifying themselves as generally healthy and having direct contact with ill or dead animals. MATERIAL AND METHODS: The research material comprised swabs from the oral cavity, nasal cavity and throat of one hundred students (Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn) who declared good health. Initial cultures on the Sabouraud medium were incubated for 72 h at 37 degrees C, then sieved in the Czapek-Dox medium, where they were macroscopically assessed after two weeks. Forcing preparations produced with use of adhesive tape, were stained methylene blue with lactofenol. RESULTS: The studies identified 9 species of fungi from four genera: Aspergillus and Penicillium (mould), Scopulariopsis and Trichophyton (dermatophytes). Penicillium chrysogenum was a dominant feature. Aspergillus fumigatus, Aspergillus niger, A. versicolor and Scopulariopsis brevicaulis were often isolated. Moulds were also accompanied by yeast-like fungi (Candida albicans, Candida tropicalis). Most of the fungi were isolated from the nasal cavity of nicotine abusers and those taking oral hormones. CONCLUSIONS: Isolation of potentially pathogenic fungi from people declaring good health may indicate the carrier state or a lowered resistance at the time of material collection. This indicates the need to put a greater emphasis on prevention in subsequent mycological examinations of environmental risk groups.

Results of long-standing mycological analyses of biological materials originating from selected organ ontocenoses--yeast and yeast-like fungi.

This paper reviews the results of an extensive monitoring study, spanning 20-years of observation from three medical centres in Olsztyn on the dynamics and species diversity of fungi most frequently colonizing the respiratory and digestive systems of humans. The experimental materials were swabs and specimens from the gastrointestinal tract, swabs from the oral cavity and pharynx, as well as sputum and bronchial fluid from the respiratory system. The biological material was subjected to routine mycological diagnostics, taxonomic determination and identification. In total, 41 species of yeast and yeast-like fungi were isolated, including 34 from the respiratory and 25 from the digestive system. In the last decade, a significant increase has been noticed in the counts of fungi, especially the gastrointestinal tract, reported from people. As many as 18 species were isolated from both systems--they were predominated by fungi of the genus Candida and their perfect forms. Worthy of notice are also frequent isolations of yeast (Saccharomyces spp.) and detection of an endemic species, Paracoccidioides brasiliensis, in the respiratory system, and of the sexual stages of Rhodosporidium diobovatum and Rhodosporidium kratochvilovae from the gastrointestinal tract.