Influence of selected dopands on the structure and microstructure of zinc and barium aluminates

Izvršena su strukturna istraživanja nanokristalnih uzoraka cinkovoga aluminata (ZnAl2O4) dopiranoga s 0-11,7 at.% Mn2+, uzoraka ZnAl2O4 dopiranoga s 0-11,6 at.% Ti4+, uzoraka barijevoga aluminata (BaAl2O4) dopiranoga s 0-8,7 at.% Eu3+ i uzoraka BaAl2O4 dopiranoga s 0-6,3 at.% Cr3+ kako bi se ispitao mehanizam ugradnje tih dopanada u ovisnosti o njihovom oksidacijskom stupnju i udjelu. Dopirani uzorci ZnAl2O4 priređeni su metodom sol-gel, a dopirani uzorci BaAl2O4 priređeni su hidrotermalnom metodom. Svi uzorci ispitani su prvenstveno pomoću rentgenske difrakcije. Rietveldovom metodom su utočnjene njihove kristalne strukture, te je ispitana i njihova mikrostruktura. Pri dopiranju cinkovoga aluminata kation Mn2+ inducira pojavu inverzne spinelne strukture cinkovoga aluminata, dok se kation Ti4+ ugrađuje isključivo na oktaedarsko mjesto strukture ZnAl2O4 zamjenjujući kation Al3+. Pri dopiranju barijevoga aluminata kation Eu3+ zamjenjuje Ba2+ s koordinacijom 9, dok kation Cr3+ samo u malom udjelu zamjenjuje Al3+ u jednom od AlO4 tetraedara strukture polaznog aluminata. Pored bitnog utjecaja na strukturu polaznih aluminata, ispitani slučajevi dopiranja imali su i znatan utjecaj na mikrostrukturu aluminata djelujući kao defekti kristalne rešetke.Structural studies of nanocrystalline samples of zinc aluminate (ZnAl2O4) doped with 0-11.7 at.% Mn2+, samples of ZnAl2O4 doped with 0-11.6 at.% Ti4+, samples of barium aluminate (BaAl2O4) doped with 0-8.7 at.% Eu3+ and samples of BaAl2O4 doped with 0-6.3 at.% Cr3+ have been performed in order to examine the dependence of dopand incorporation mechanism on its oxidation state and doping level. Doped ZnAl2O4 samples were prepared by the sol-gel method, while doped BaAl2O4 samples were prepared by the hydrothermal method. They were examined by X-ray powder diffraction. Crystal structures of samples were refined by the Rietveld method and their microstructure was determined simultaneously. Manganese doping of zinc aluminate caused an appearance of partial inverse spinel structure in zinc aluminate, Mn2+ occupying both tetrahedral and octahedral sites of the spinel structure. In doping, cation Ti4+ incorporated in the octahedral site of ZnAl2O4 structure solely, substituting for Al3+. In doping of BaAl2O4 cation Eu3+ substitutes for 9-coordinated Ba2+, while only a small content of Cr3+ substitutes for Al3+ in one of the available AlO4 tetrahedra, respectively. Besides the strong influence on structure of zinc aluminates and of barium aluminates, doping also influences their microstructure, because the dopand cations act as defects in the crystal structure lattice

Nadomjesna terapija intravenoznim imunoglobulinima kod djece oboljele od primarne imunodeficijencije: sestrinske smjernice

Primary immunodeficiency diseases are chronic disorders which are characterized by increased sensitivity of the organism to infections because one or more parts of the body\u27s immune system is missing. Immunoglobulins are normal components of the human body with the main role in the immune defense. Children with primary immunodeficiency have little or no antibodies and lifelong routine replacement therapy is the only effective treatment which represents the gold standard in treatment. The purpose of this therapy is to prevent acute infections and reduce complications resulting from infection. A nurse equipped with knowledge and competences is an indispensable link in the safe and quality administration of immunotherapy and in providing immediate psychological support to the child and the entire family. Nurses administer 90% of all intravenous immunoglobulin therapy transfusions according to the provisions of the physician. The paper presents findings of a research study into nurse´s perceptions about the Immunoglobulin replacement therapy. This paper represents nursing guidelines before, during and after administering intravenous immunoglobulin in children with primary immunodeficiency disease.Primarne imunodeficijencije stanja su koja odlikuje povećana osjetljivost organizma na infekcije zbog nedostataka jedne ili više komponenti imunološkog sustava. Imunoglobulini su normalni sastavni dijelovi ljudskog tijela s glavnom ulogom u imunološkoj obrani. Djeca koja boluju od primarne imunodeficijencije imaju ih malo ili ih uopće nemaju te kod njih cjeloživotna nadomjesna terapija imunoglobulina (IgG) predstavlja jedini učinkovit tretman kao zlatni standard u liječenju primarnih imunodeficijencija. Svrha je takve terapije prevencija akutnih infekcija te smanjenje komplikacija nastalih kao posljedica infekcije. Medicinska sestra sa svojim znanjem i kompetencijama neizostavna je spona u sigurnoj i kvalitetnoj primjeni imunoterapije, u pružanju neposredne psihičke potpore djetetu i cijeloj obitelji te je upravo ona primjenjuje u 90% slučajeva prema pisanoj odredbi liječnika. Pregledom literature prikazane su spoznaje o percepciji medicinskih sestara u vezi s terapijom imunoglobulinima. Ovaj rad predstavlja smjernice medicinskim sestrama za skrb prije, tijekom i nakon primjene intravenskih imunoglobulina kod djece s primarnom bolešću imunodeficijencije

The New Ion-Selective Electrodes Developed for Ferric Cations Determination, Modified with Synthesized Al and Fe−Based Nanoparticles

The solid-state ion-selective electrodes presented here are based on the FePO4 :Ag2S:polytetrafluoroethylene (PTFE) = 1:1:2 with an addition of (0.25–1)% microwave-synthesized hematite (α-Fe2O3 ), magnetite (Fe3O4 ), boehmite [γ-AlO(OH)], and alumina (Al2O3 ) nanoparticles (NPs) in order to establish ideal membrane composition for iron(III) cations determination. Synthesized NPs are characterized with Fourier-Transform Infrared (FTIR) spectroscopy, Powder X-Ray Diffraction (PXRD), and Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDS). The iron oxides NPs, more specifically, magnetite and hematite, showed a more positive effect on the sensing properties than boehmite and alumina NPs. The hematite NPs had the most significant effect on the linear range for the determination of ferric cations. The membrane containing 0.25% hematite NPs showed a slope of −19.75 mV per decade in the linear range from 1.2·10−6 to 10−2 mol L−1 , with a correlation factor of 0.9925. The recoveries for the determination of ferric cations in standard solutions were 99.4, 106.7, 93.6, and 101.1% for different concentrations

Magnetoelectric Coupling Springing Up in Molecular Ferroelectric: [N(C2H5)3CH3][FeCl4]

A molecule-based ferroelectric triethylmethylammonium tetrachloroferrate(III) ([N(C2H5)3CH3][FeCl4]) powder was designed as a multifunctional material exhibiting excellent multiple bistability. Prepared by the slow evaporation method at room temperature, the compound crystallizes in the non- centrosymmetric assembly of hexagonal symmetry (P63mc space group) which undergoes a reversible temperature- triggered phase transition pinpointed at 363 K to the centrosymmetric packing within the P63/mmc space group. Aside from the inseparable role of the symmetry-breaking process smoothly unveiled from the X-ray powder diffraction data, a striking change in the dielectric permittivity observed during the paraelectric-to- ferroelectric phase transition directly discloses the bistable dielectric behavior—an exceptionally high increase in the dielectric permittivity of about 360% at 100 kHz across the heating and cooling cycles is direct proof showing the highly desirable stimuli- responsive electric ordering in this improper ferroelectric architecture. Due to the magnetically modulated physical properties resulting in the coupling of magnetic and electric orderings, the flexible assembly of [N(C2H5)3CH3] [FeCl4] could be used to boost the design and development of novel magnetoelectric device

Single‐step preparation of rutile‐type CrNbO 4

Chromium niobate and tantalate (CrNbO4 and CrTaO4) were synthesized by pyrolysis of the oxalate‐based heterometallic complexes [Cr2(bpy)4(μ-O)4Nb2(C2O4)4]·3H 2O (Cr‐Nb) and [Cr(bpy)2(H2O)(μ‐O)Ta(C2O4)3]2·3.5H2O (Cr‐Ta) (bpy = 2, 2'‐bipyridine). Compared to conventional solid‐state synthesis, herein studied oxides are prepared at lower temperatures, in one step without repeating grinding procedures. The structure, morphology, and optical properties of the as‐synthesized oxides were characterized using powder X‐ray diffraction (PXRD), field emission scanning electron microscopy (SEM), the thermogravimetric and differential thermal analysis (TG/DTA) and UV‐vis diffuse reflectance spectroscopy (UV‐vis DRS). The determined band gap energies of CrNbO4 and CrTaO4 are 2.39 and 2.82 eV, respectively, which prompted us to investigate photocatalytic activity of these oxides in degradation of dyes. Microscopy studies show that the particles of both oxides began to aggregate into bigger particles, leading to an increase in grain size. Additionally, magnetization measurements on both oxides revealed spin‐glass behavior at low temperatures