31 research outputs found

    Ultrasound-assisted synthesis of nanostructured LiFePO4/C composite

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    Poster presented at the Women in Nano Winter School, Kranjska Gora, Slovenia, February 7-9, 200

    Differently shaped nanocrystalline (Fe, Y)3O4 and its adsorption efficiency toward inorganic arsenic species

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    Herein we report effects of partial substitution of Fe3+ by Y3+ in magnetite (Fe3O4) on morphology and inorganic arsenic species adsorption efficiency of the Fe3−x Y x O4 nanoparticles formed. The series of Fe3−x Y x O4 (x = 0.00, 0.042 and 0.084, labeled as Y00, Y05 and Y10, respectively) was synthesized using co-precipitation followed by microwave-hydrothermal treatment (MW) at 200 °C. With increase of yttrium content (x value), both the morphological inhomogeneity of the samples and the fraction of spinel nanorods as compared to spinel pseudospherical particles increased. By both transmission electron microscopy and x-ray powder diffraction analyses, it was determined that the direction of growth of the spinel nanorods is along the [110] crystallographic direction. The Fe3−x Y x O4 affinities of adsorption toward the inorganic arsenic species, As(III) (arsenite, AsO3 3−) and As(V) (arsenate, AsO4 3−), were investigated. Increased Y3+ content related to changes in sample morphology was followed by a decrease of As(III) removal efficiency and vice versa for As(V). The increase in Y3+ content, in addition to increasing the adsorption capacity for As(V), significantly expanded the optimum pH range for the maximum removal and decreased the contact time for necessary 50% removal (t 1/2) of As(V) (Y00: pH 2–3, t 1/2 = 3.12 min; Y05: pH 2–6, t 1/2 = 2.12 min and Y10: pH 2–10, t 1/2 = 1.12 min). The results point to incorporation of Y3+ in the crystal lattice of magnetite, inducing nanorod spinel structure formation with significant changes in sorption properties important for the removal of inorganic arsenic from waters.This is the peer-reviewed version of the article: Nanotechnology, 2019, 30, 47, 475702, [https://dx.doi.org/10.1088/1361-6528/ab3ca2]Published version: [http://cer.ihtm.bg.ac.rs/handle/123456789/3243

    Characterization of a Novel Cutaneous Human Papillomavirus Genotype HPV-125

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    The DNA genome of a novel HPV genotype, HPV-125, isolated from a hand wart of an immuno-competent 19-year old male was fully cloned, sequenced and characterized. The full genome of HPV-125 is 7,809-bp in length with a GC content of 46.4%. By comparing the nucleotide sequence of the complete L1 gene, HPV-125 is phylogenetically placed within cutaneotrophic species 2 of Alphapapillomaviruses, and is most closely related to HPV-3 and HPV-28. HPV-125 has a typical genomic organization of Alphapapillomaviruses and contains genes coding for five early proteins, E6, E7, E1, E2 and E4 and two late capsid proteins, L1 and L2. The genome contains two non-coding regions: the first located between the L1 and E6 genes (nucleotide positions 7,137–7,809, length 673-bp) and the second between genes E2 and L2 (nucleotide positions 3,757–4,216, length 460-bp). The E6 protein of HPV-125 contains two regular zinc-binding domains at amino acid positions 29 and 102, whereas the E7 protein exhibits one such domain at position 50. HPV-125 lacks the regular pRb-binding core sequence within its E7 protein. In order to assess the tissue predilection and clinical significance of HPV-125, a quantitative type-specific real-time PCR was developed. The 95% limit-of-detection of the assay was 2.5 copies per reaction (range 1.7–5.7) and the intra- and inter-assay coefficients of variation were 0.47 and 2.00 for 100 copies per reaction, and 1.15 and 2.15 for 10 copies per reaction, respectively. Testing of a representative collection of HPV-associated mucosal and cutaneous benign and malignant neoplasms and hair follicles (a total of 601 samples) showed that HPV-125 is a relatively rare HPV genotype, with cutaneous tropism etiologically linked with sporadic cases of common warts

    Characterization of Novel Cutaneous Human Papillomavirus Genotypes HPV-150 and HPV-151

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    DNA from two novel HPV genotypes, HPV-150 and HPV-151, isolated from hair follicles of immuno-competent individuals, was fully cloned, sequenced and characterized. The complete genomes of HPV-150 and HPV-151 are 7,436-bp and 7,386-bp in length, respectively. Both contain genes for at least six proteins, namely E6, E7, E1, E2, L2, L1, as well as a non-coding upstream regulatory region located between the L1 and E6 genes: spanning 416-bp in HPV-150 (genomic positions 7,371 to 350) and 322-bp in HPV-151 (genomic positions 7,213 to 148). HPV-150 and HPV-151 are phylogenetically placed within the Betapapillomavirus genus and are most closely related to HPV-96 and HPV-22, respectively. As in other members of this genus, the intergenic E2-L2 region is very short and does not encode for an E5 gene. Both genotypes contain typical zinc binding domains in their E6 and E7 proteins, but HPV-151 lacks the regular pRb-binding core sequence within its E7 protein. In order to assess the tissue predilection and clinical significance of the novel genotypes, quantitative type-specific real-time PCR assays were developed. The 95% detection limits of the HPV-150 and HPV-151 assays were 7.3 copies/reaction (range 5.6 to 11.4) and 3.4 copies/reaction (range 2.5 to 6.0), respectively. Testing of a representative collection of HPV-associated mucosal and cutaneous benign and malignant neoplasms and hair follicles (total of 540 samples) revealed that HPV-150 and HPV-151 are relatively rare genotypes with a cutaneous tropism. Both genotypes were found in sporadic cases of common warts and SCC and BCC of the skin as single or multiple infections usually with low viral loads. HPV-150 can establish persistent infection of hair follicles in immuno-competent individuals. A partial L1 sequence of a putative novel HPV genotype, related to HPV-150, was identified in a squamous cell carcinoma of the skin obtained from a 64-year old immuno-compromised male patient

    An enhanced thermoelectric figure of merit for Sr(Ti0.8Nb0.2)O3 based on a Ruddlesden–Popper-polytype-induced microstructure

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    Platelet crystals based on Ruddlesden–Popper (RP) polytypes prepared by molten-salt synthesis wereused to influence the microstructural development of Nb-doped SrTiO3(STO;Nb) perovskite and,consequently, to change the thermoelectric properties. Electron microscopy revealed intergrowth ofRP-polytypic phases within the STO;Nb solid-solution matrix phase. The morphology of the grains variedfrom isotropic to anisotropic, containing polytypic faults up to 100 �m in length. Such a microstructureincreased the thermoelectric figure of merit by 50% at 650◦C, due to substantially enhanced electricalconductivity, slightly increased Seebeck coefficient and lowered thermal conductivity

    Analysis of the Phase Transition and the Domain Structure in K\u3csub\u3e0.5\u3c/sub\u3eBi\u3csub\u3e0.5\u3c/sub\u3eTiO\u3csub\u3e3\u3c/sub\u3e Perovskite Ceramics by \u3cem\u3eIn Situ\u3c/em\u3e XRD and TEM

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    The local crystal and domain structures of K0.5Bi0.5TiO3 ceramics were investigated by transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). The individual grains showed a lamellar domain structure, and on the basis of spot splitting along the characteristic crystallographic directions, 90°a–a- and 90°a–c-type domains were identified. Furthermore, lamellar features within the 90° domains were observed, which we presumed were 180° domains; however, in the case of P4mm structures they cannot be distinguished by SAED. The 90° domain boundaries were (011) and (101) twin planes, typical for tetragonal perovskites. The domains could be designated as rotation twins, where the symmetry element describing the relationship between two twin domains is a twofold twin axis [011]/[101] and the symmetry operation is a 180° rotation. In order to determine the dynamics and the temperature of the phase transformation from the tetragonal to the cubic structures, high-temperature XRD and in situ heating TEM analyses were performed. The results showed a gradual phase transformation in the temperature range from ~280° to ~450°C, where some grains lost their polar domains at a lower temperature than others. These findings confirmed the existence of a binary stability field in which the cubic and tetragonal structures coexist
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