Polymers – from the primeval beginning to plastics and elastomers

Polazeći od fi lozofskih misli O. Spenglera i Aristotela, utvrđeno je da su polimeri prastari, jer sežu tamo do postanka osnovnih prirodnih organskih i anorganskih polimera. Istodobno je uočeno da se riječ polimeri učestalo upotrebljava kao zajedničko ime za plastiku i elastomere. Od osnovnih prirodnih organskih polimera: bjelančevina, nukleinskih kiselina i polisaharida dug je povijesni put. Taj se put pokušalo opisati dijagramom toka, tokovnikom. Za navedeni opis potrebne su brojne defi nicije, ali i motivacijska osnova. To je učinjeno u dodatcima A i B. Zaključak je istraživanja: praoblikovanje i prastrukturiranje prirodnih polimera staro je oko 3,5 milijardi godina, a humana obradba razdvajanjem oko 3,4 milijuna godina. Svatko tko se bavi polimerima trebao bi biti obrazovan na odgovarajućoj razini potrebnog znanja s razvijenim tokovnikom.Based on the philosophic ideas of O. Spengler and Aristotle it has been determined that polymers are ancient since they reach back all the way to the origin of the basic natural organic and inorganic polymers. At the same time it has been noted that the word polymers is frequently used as a common name for plastics and elastomers. Since the basic natural organic polymers: proteins, nucleic acids, and polysaccharides there is a long historical path. An attempt was made to present this path by means of a fl ow chart. For the mentioned description numerous defi nitions are required, as well as a motivating basis. This was done in Annexes A and B. The conclusion of the research is that primary shaping and primary structuring of natural polymers is around 3.5 billion years old and human separation with natural tools about 3.4 million years. Anyone involved in polymers should be educated at an adequate level of the necessary knowledge with the developed fl owchart

Bacteriuria in Paediatric Oncology Patients: Clinical Features, Distribution and Antimicrobial Susceptibility of Bacterial Pathogens at University Hospital Centre Zagreb, Croatia over a 4-Year Period

Bacteriuria in paediatric oncology patients have not been well studied. This retrospective study analysed clinical features, distribution and antimicrobial susceptibility of bacterial pathogens cultured from urine in paediatric oncology patients over a 4-year period (2019–2022). A total of 143 episodes of bacteriuria were documented in 74 patients. Neutropenia was present in 17.5% (25/143), symptoms in 25.9% (37/143) and urinary catheter in 7.0% (10/143) episodes. Symptomatic bacteriuria episodes were statistically significantly more frequent in patients with neutropenia (p = 0.0232). The most common bacterial pathogens were Escherichia coli (n = 49; 32.2%), Klebsiella spp. (n = 34; 22.4%), Pseudomonas aeruginosa (n = 22; 14.5%) and Enterococcus spp. (n = 21; 13.8%). Extended-spectrum β-lactamases-producing (ESBL) Enterobacterales were found in 11 episodes (11/143; 7.7%) with the highest proportion among Klebsiella pneumoniae isolates (n = 7/34; 20.6%). No carbapenem-resistant Enterobacterales, multidrug-resistant P. aeruginosa or vancomycin-resistant Enterococcus spp. were found. The most important novelties are demonstrating P. aeruginosa as one of the prominent bacteriuria pathogens in this patient population, presence of ESBL isolates and carbapenem-resistant P. aeruginosa later during hospitalization highlights the need for appropriate antimicrobial treatment. However, because of the small number of symptomatic patients, further studies are needed to clarify the importance of including urine culture in the diagnostic process in patients with febrile neutropenia

Cortisol Concentrations in Hair, Blood and Milk of Holstein and Busha Cattle

Cortisol levels were measured in hair, blood and milk in two different cattle breeds, kept under different breeding conditions and with different genetic merit for milk production. Cows and heifers of Holstein and Busha breeds were selected for the study. Cortisol concentration was determined by immunoassays. Cortisol accumulation was determined in proximal (close to the skin) and distal (far from the skin) segments of the hair shaft. The influence of hair colour and washing prior to extraction and analysis was also examined in order to establish additional factors that may have an impact on hair cortisol concentrations. Concentrations of cortisol determined in the proximal and distal segments of the shaft were significantly higher in Holstein than Busha cows and heifers (P LT 0.05 and P LT 0.01, respectively). In Holstein cows, no significant difference was found between concentrations in black and white hair. In hair washed with isopropanol, cortisol concentration was significantly lower compared to unwashed hair (P LT 0.01). Thus, cortisol concentration in hair varies with the technique of hair processing (washing), but not with colour in Holstein cows. Blood serum cortisol concentrations in Holstein cows and heifers were significantly higher than in Busha cows and heifers, (P LT 0.01 and P LT 0.05, respectively). Milk cortisol in Holstein cows was significantly higher than in Busha cows (P LT 0.05). The higher cortisol concentrations in Holstein cows are assumed to be the result of intensive breeding and physiological adaptation to high milk production

Potenciali razvoja turizma na Unescovih lokacijah svetovne dediščine v Sloveniji

Turizem kot najhitreje razvijajoča se panoga skriva veliko potencialov, ki v Sloveniji še nimajo pravega mesta. Dediščinski turizem je eden tistih, ki se počasi odpira v slovenskem okolju. Morda lahko iščemo razlog v identiteti. Kljub temu, da ima Slovenija že več kot tridesetletno zgodovino prvega vpisa v Unescovo kulturno dediščino, je le-ta v nacionalnem smislu še vedno neprepoznavna ali slabo prepoznavna. Odgovornost lahko iščemo tako na državni ravni kot na lokalni ravni, saj se logotip Unesca ne uporablja dosledno na vseh lokacijah. A ko prepoznamo nevarnost, jo lahko zlahka spremenimo v potencial in spremembo z namenom razvoja. Tako je tudi z dediščinskim turizmom, ki ga predstavljajo Unescove lokacije v Sloveniji