Structure, magnetic and electronic properties of new 1111-type and 42622-type transition metal-based oxyarsenides

Discovery of high-temperature superconductors aroused a great interest in studies on these materials. In 1987 an yttrium-based compound YBCO (Yttrium-Barium- Copper-Oxide) was synthesised with Tc at 93 K. It was immediately evident that the BCS theory does not explain the pairing mechanism in these oxide-based superconductors, which predicted that a maximum Tc of about 30 K could be achieved. Layered copper oxides were for a long time the most studied high-Tc superconductors. With the discovery, at the beginning of 2008, by Kamihara of a new non-cuprate high-Tc superconductor a different path of studies had opened. This family of quaternary oxyarsenides LaO1-xFxFeAs was surprising due to the presence of Fe, which should lead to long-range magnetic order suppressing superconductivity. Although the parent compound LaFeAsO is not superconducting, electron doping (by partial substitution of O2- with F-) leads to superconductivity with Tc of 26 K. Since these discoveries there has been extensive research on the family of rare-earth quaternary oxypnictides with general formula REFaAsO (RE = La, Sm, Ce, Nd, Pr, Gd, Tb, Dy) and with Tc reaching 55 K for electron doped SmFeAsO. A study of new NdFeAsO family with Sr doping on Nd site was conducted. Synthesis of Nd1-xSrxFeAsO compounds and their further characterisation revealed that hole doping in these materials is a successful route to achieve superconductivity. Partial substitution of Nd3+ by Sr2+ with small doping level (x = 0.05) shows semiconducting type behaviour, while increasing doping level leads to the emergence of metallic conductivity and with level of doping 20% obtaining superconductivity at Tc = 13.5 K. These materials adopt a simple tetragonal crystal structure (space group P4/nmm), which undergoes a structural phase transition on cooling to orthorhombic symmetry (space group Cmma). The changes of structural, electronic and magnetic properties with doping level show very different behaviour – non-symmetric to the electron doped side of the phase diagram. The family of Fe-As based superconductors has expanded further by the discoveries of A1-xA’xFe2As2 (A = Alkaline Earth, A’ = Alkali metal), LiFeAs and NaFeAs phases, Sr3Sc2Fe2As2O5. A series of iron-based oxyarsenides with general formula Sr4M12O6M2 2As2 (M1 = Sc, Cr, V; M2 = Fe, Co, Ni) was synthesised and their structure was studied using powder X-ray and neutron diffraction. These materials adopt tetragonal crystal structure (space group P4/nmm) in analogy with REFeAsO systems. The Fe-As planes are sandwiched between perovskite K2NiF4-type oxide layers of Sr4M2O6 (MI = Sc, Cr, V), the large size of which creates a large distance between Fe-As planes. In spite of structural analogy with REFeAsO these new materials show a different behaviour from REFeAsO, which is absence of a structural phase transition on cooling. Both Sr4V2O6Fe2As2 and Sr4Sc2O6Ni2As2 compounds are superconducting without doping with Tc at 28 K and 2.5 K respectively. Neither Sr4Sc2O6Fe2As2 nor Sr4Cr2O6Fe2As2 show these properties, but are good parent compounds for doping, which may lead to producing compounds that achieve superconductivity. Further research was made with synthesising doped Sr4Cr2O6Fe2As2 with doping on Fe site with Co. The structure and magnetic and electrical properties of these compounds were studied and proved to show superconducting behaviour with Tc up to 17.5 K for 5% Co doping

Structural and electronic response upon hole-doping of rare-earth iron oxyarsenides Nd1-xSrxFeAsO (0 < x < 0.2)

Hole-doping of NdFeAsO via partial replacement of Nd3+ by Sr2+ is a successful route to obtain superconducting phases (Tc = 13.5 K for a Sr2+ content of 20%); however, the structural and electronic response with doping is different from and non-symmetric to that in the electron-doped side of the phase diagram.Comment: 4 pages, 4 figure

Crystal structure of the new FeSe1-x superconductor

The newly discovered superconductor FeSe1-x (x=0.08, Tconset=13.5 K at ambient pressure rising to 27 K at 1.48 GPa) exhibits a structural phase transition from tetragonal to orthorhombic below 70 K at ambient pressure - the crystal structure in the superconducting state shows remarkable similarities to that of the REFeAsO1-xFx (RE = rare earth) superconductorsComment: Chem. Commun. (2008

Serological characterization of the enterobacterial common antigen substitution of the lipopolysaccharide of "Yersinia enterocolitica" O:3

Enterobacterial common antigen (ECA) is a polysaccharide present in all members of Enterobacteriaceae anchored either via phosphatidylglycerol (PG) or LPS to the outer leaflet of the outer membrane (ECAPG and ECALPS, respectively). Only the latter form is ECAimmunogenic. We previously demonstrated that Yersinia enterocolitica O: 3 and its rough (Ospecific polysaccharide-negative) mutants were ECA-immunogenic, suggesting that they contained ECALPS; however, it was not known which part of the LPS core region was involved in ECA binding. To address this, we used a set of three deep-rough LPS mutants for rabbit immunization. The polyvalent antisera obtained were: (i) analysed for the presence of anti-LPS and anti-ECA antibodies; (ii) treated with caprylic acid (CA) to precipitate IgM antibodies and protein aggregates; and (iii) adsorbed with live ECA-negative bacteria to obtain specific anti-ECA antisera. We demonstrated the presence of antibodies specific for both ECAPG and ECALPS in all antisera obtained. Both CA treatment and adsorption with ECA-negative bacteria efficiently removed anti-LPS antibodies, resulting in specific anti-ECA sera. The LPS of the ECALPS-positive deepest-rough mutant contained only lipid A and 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo) residues of the inner core, suggesting that ECALPS was linked to the Kdo region of LPS in Y. enterocolitica O:3

Electronic book as an element of publishers offer. Project of marketing campaign of electronic book for youth

W pracy podjęto próbę omówienia specyfiki książki elektronicznej, rozumianej jako nowy trend na rynku wydawniczym. Celem jest zaproponowanie kampanii promocyjnej e-booka polskiego autora, mającej na celu przyciągnięcia zainteresowania młodzieży i przekonania jej do zaprzestania pozyskiwania książek z nielegalnych źródeł. Zebrany materiał źródłowy, publikacje wydane w języku polskim i angielskim w latach 2005-2015, został poddany analizie metodą analizy i krytyki piśmiennictwa. Uwzględniono elementy technologiczne składające się na definicję oraz genezę e-booka, czynniki wpływające na odbiór i popularność e-książki wśród młodzieży oraz opisano działalność kluczowych dystrybutorów książek elektronicznych w Polsce. Następnie zanalizowano popularnie obecnie narzędzia promocji umożliwiające kontakt z czytelnikiem: strony internetowe, blogi, portale społecznościowe i aplikacje mobilne, zwracając uwagę na zamieszczane przez instytucje książki i autorów typy treści w mediach społecznościowych. Rezultatem pracy jest projekt kampanii książki elektronicznej dla młodzieży przeprowadzony w mediach społecznościowych, z wykorzystaniem aktywizujących działań promocyjnych.This paper attempts to discuss the specificity of an electronic book, understand as a new trend in the publishing market. The aim of the paper is to propose a campaign of e-book of Polish author in order to attract youth interest and encourage them to end acquiring books from illegal sources. The collected source material, publications released in Polish and English languages between 2005-2015 year, were analyzed by the critical literature review method. It includes technological elements that concur to definition and origins of e-book, factors affecting the perception and popularity of e-books among youth and there were described activities of the most important distributors of electronic books in Poland. Next, there were analyzed currently popular tools of promotion, which enable communication with readers, such as: websites, blogs, social networks and mobile applications, paying attention to feature types of contents by book institutions and authors in social media. The result of this paper is project of marketing campaign of electronic book for youth in social media with use of active promotion measures

Aesthetic and informative function of romance book covers

W pracy podjęto próbę omówienia rozwoju oraz charakterystycznych cech książek z gatunku romans, determinujących koncepcje okładek i pełnionych przez nie funkcji. Celem jest porównanie znaczenia oraz odbioru estetycznej i informacyjnej roli okładek romansów u konsumenta i wydawcy na przykładzie wybranych oficyn. Część teoretyczna pracy, obejmująca materiał źródłowy, publikacje wydane w języku polskim i angielskim w latach 2006-2017, została poddana analizie metodą analizy i krytyki piśmiennictwa. Uwzględnia ona zagadnienia związane z definicją romansu, jako gatunku literackiego, genezę, cechy charakterystyczne i podgatunki, czytelników literatury kobiecej oraz ich motywacji konsumenckich, a także najważniejsze polskie wydawnictwa, specjalizujące się w publikowaniu romansów. Następnie przeanalizowano tematykę okładki, jej definicję i rozwój, a także pełnione funkcje estetyczną i informacyjną, rozpatrywane w kontekście okładzin książek należących do gatunku romans. Zwieńczeniem pracy jest omówienie badań przeprowadzonych wśród czytelników romansu oraz wybranych wydawnictw publikujących literaturę kobiecą. W badaniach zastosowano metodę ilościową, natomiast wykorzystaną techniką badawczą, dla potrzeb obu części badań jest ankieta internetowa.This paper attempts to discuss the development and characteristic features of books from the romance genre, determining the conception of covers and their functions. The aim of the paper is to compare the importance and reception of aesthetic and informative role of romance book covers, from readers and publishers point of views. The theoretic part of the thesis, containing source material, publications released in Polish and English language between 2006-2017, were analyzed by the critical literature review method. It includes issues related to definition of romance books as a literary genre, genesis, characteristic features, and subgenres, romance book readers and their consumer motivations, also the most important polish publishers, specializing in publishing romance books. Next, there was analysis of the subject matter of the book cover, its definition and development, fulfilled aesthetic and informative functions, considered in the context of book covers belonging to the romance genre. The culmination of the paper is discussion of research carried out among romance book readers and selected publishing houses, which publishes women’s fiction. A quantitative method was used in the research, while the research technique used in both parts of the study, is the online survey

Serological characterization of the enterobacterial common antigen substitution of the lipopolysaccharide of Yersinia enterocolitica O : 3

Enterobacterial common antigen (ECA) is a polysaccharide present in all members of Enterobacteriaceae anchored either via phosphatidylglycerol (PG) or LPS to the outer leaflet of the outer membrane (ECAPG and ECALPS, respectively). Only the latter form is ECAimmunogenic. We previously demonstrated that Yersinia enterocolitica O: 3 and its rough (Ospecific polysaccharide-negative) mutants were ECA-immunogenic, suggesting that they contained ECALPS; however, it was not known which part of the LPS core region was involved in ECA binding. To address this, we used a set of three deep-rough LPS mutants for rabbit immunization. The polyvalent antisera obtained were: (i) analysed for the presence of anti-LPS and anti-ECA antibodies; (ii) treated with caprylic acid (CA) to precipitate IgM antibodies and protein aggregates; and (iii) adsorbed with live ECA-negative bacteria to obtain specific anti-ECA antisera. We demonstrated the presence of antibodies specific for both ECAPG and ECALPS in all antisera obtained. Both CA treatment and adsorption with ECA-negative bacteria efficiently removed anti-LPS antibodies, resulting in specific anti-ECA sera. The LPS of the ECALPS-positive deepest-rough mutant contained only lipid A and 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo) residues of the inner core, suggesting that ECALPS was linked to the Kdo region of LPS in Y. enterocolitica O:3