Shungite – a carbon-mineral rock material: Its sinterability and possible applications

The paper presents results of the influence of mechanical activation of shungite, a carbon-mineral rock material rich in silica and carbon, on its sintering behaviour, and obtaining of pure SiC ceramics. The mechanical activation of the starting powder was performed in a high-energy ball mill in time intervals from 30 to 480 min. The phase composition of the starting powders and sintered samples was analysed by the X-ray diffraction method. The first traces of SiC were detected after sintering at 1350 °C for 2 h in an Ar atmosphere, along with traces of unreacted SiO2. The scanning electron microscopy was performed in order to determine changes in the microstructure. Sintering was performed at various temperatures for 2 h, in an Ar atmosphere and a vacuum. Dielectric properties of the sintered samples were measured in the frequency range from 1 to 500 MHz. The obtained results indicate that the sintered powder is a good candidate for applications as an absorber of electromagnetic waves in microwave engineering

Farmaceuti i COVID-19 u Srbiji: promocija vakcinacije u javnim apotekama u Republici Srbiji

Uvod i cilj. Pandemija COVID-19 potvrdila je važnost uloge farmaceuta u očuvanju i unap- ređenju javnog zdravlja. Cilj rada je da prikaže aktivnosti farmaceutskih udruženja u Republici Srbiji u promociji vakcinacije. Metode. Savez farmaceutskih udruženja Srbije (SFUS), Udruženje farmaceuta Beograd, Udruženje farmaceuta Vojvodine, Udruženje farmaceuta Zapadne Srbije 1836, Udruženje far- maceuta Nišavsko-pirotskog regiona, Savez privatnih apotekara Srbije i Inicijativa za farma- ciju organizovali su Webinar posvećen ulozi farmaceuta u imunizaciji. Navedena udruženja inicirala su izradu informativne brošure „Covid-19 vakcine u Srbiji”. Brošuru je izradila Katedra za mikrobiologiju i imunologiju Farmaceutskog fakulteta Univerziteta u Beogradu (FFUB) u saradnji sa Agencijom za lekove i medicinska sredstva Srbije. Dizajn brošure uradila je Nacio- nalna Asocijacija Studenata Farmacije – Srbija. Štampanje brošure omogućilo je Ministarstvo zdravlja Republike Srbije u okviru projekta „Hitan odgovor Republike Srbije na COVID-19“. Rezultati. Webinaru održanom 13.02.2021. prisustvovalo je 594 farmaceuta. Brošura je sadržala najznačajnije podatke o COVID-19 vakcinama u Srbiji, ali i odgovore na neka najče- šće postavljana pitanja od strane građana. Napisana je na osnovu najrelevantnijih dostupnih naučnih podataka, a sadržaj je ažuriran tri puta. Brošura je štampana u 150000 besplatnih primeraka i distribuirana u javne apoteke. Apoteke su bile mesto dalje distribucije brošura za- interesovanim pacijentima. Brošura je takođe bila dostupna u e-formatu na sajtu FFUB, SFUS, i na sajtovima brojnih ustanova javnog zdravlja Srbije., a izazvala je i veliko interesovanje u medijima i na društvenim mrežama. Zaključak. Organizacijom webinara, učešćem u izradi i distribuciji brošure o vakcinama, farmaceuti su aktivno učestvovali u informisanju stanovništva, promociji vakcinacije i tako potvrdili značaj farmaceutske zdravstvene zaštite u uslovima pandemije

Genomic data provide new insights on the demographic history and the extent of recent material transfers in Norway spruce

Primeval forests are today exceedingly rare in Europe, and transfer of forest reproductive material for afforestation and improvement has been very common, especially over the last two centuries. This can be a serious impediment when inferring past population movements in response to past climate changes such as the last glacial maximum (LGM), some 18,000 years ago. In the present study, we genotyped 1,672 individuals from three Picea species (P. abies, P. obovata, and P. omorika) at 400K SNPs using exome capture to infer the past demographic history of Norway spruce (P. abies) and estimate the amount of recent introduction used to establish the Norway spruce breeding program in southern Sweden. Most of these trees belong to P. abies and originate from the base populations of the Swedish breeding program. Others originate from populations across the natural ranges of the three species. Of the 1,499 individuals stemming from the breeding program, a large proportion corresponds to recent introductions from mainland Europe. The split of P. omorika occurred 23 million years ago (mya), while the divergence between P. obovata and P. abies began 17.6 mya. Demographic inferences retrieved the same main clusters within P. abies than previous studies, that is, a vast northern domain ranging from Norway to central Russia, where the species is progressively replaced by Siberian spruce (P. obovata) and two smaller domains, an Alpine domain and a Carpathian one, but also revealed further subdivision and gene flow among clusters. The three main domains divergence was ancient (15 mya), and all three went through a bottleneck corresponding to the LGM. Approximately 17% of P. abies Nordic domain migrated from P. obovata ~103K years ago, when both species had much larger effective population sizes. Our analysis of genomewide polymorphism data thus revealed the complex demographic history of Picea genus in Western Europe and highlighted the importance of material transfer in Swedish breeding program

Shungite – a carbon-mineral rock material: Its sinterability and possible applications

© 2019 University of Novi Sad, Faculty of Technology. All rights reserved. The paper presents results of the influence of mechanical activation of shungite, a carbon-mineral rock material rich in silica and carbon, on its sintering behaviour, and obtaining of pure SiC ceramics. The mechanical activation of the starting powder was performed in a high-energy ball mill in time intervals from 30 to 480 min. The phase composition of the starting powders and sintered samples was analysed by the X-ray diffraction method. The first traces of SiC were detected after sintering at 1350 °C for 2 h in an Ar atmosphere, along with traces of unreacted SiO2. The scanning electron microscopy was performed in order to determine changes in the microstructure. Sintering was performed at various temperatures for 2 h, in an Ar atmosphere and a vacuum. Dielectric properties of the sintered samples were measured in the frequency range from 1 to 500 MHz. The obtained results indicate that the sintered powder is a good candidate for applications as an absorber of electromagnetic waves in microwave engineering

New palynological and tephrochronological investigations of two salt lagoons on the island of Mljet, south Dalmatia, Croatia

In the sediments of both of the investigated lakes, the tephra from the Mercato-Ottaviano eruption (Vesuvius, southern Italy) (ca. 7900 B.P.) could be identified. The palynological investigations show that from ca. 9000-7200 B.P. (8000-6000 cal B.C.) deciduous oak forests predominated, with only a few representatives of Mediterranean vegetation. At the transition to the central European Atlantic Period those forests changed to an open vegetation type, dominated byJuniperus andPhillyrea. At about 5500 B.P. (4400 cal B.C.), theJuniperus-Phillyrea vegetation was replaced byQuercus ilex woodland that still occurs on the island of Mljet today and is considered to be the natural vegetation of the Dalmatian coastland. The associated vegetation of theQ. ilex forests changed several times. At the beginning of theQ. ilex period,Juniperus values were still high, but soon they decreased andErica spread. In more recent times theQ. ilex forests were partially replaced by plantations ofPinus halcpensis. Indicators of human impact are sparse throughout the pollen record. Clear evidence for human influence exists only from ca. 3100 B.P. (1300 cal B.C.) whenJuglans andPinus halepensis were introduced to the area. Later,Olea andSecale cultivation can be suggested and further spreading ofJuniperus indicates use of the land as pasture