Cu codoping control over magnetic precipitate formation in ZnCoO nanowires

Using electrodeposition, we have grown nanowires of ZnCoO with Cu codoping concentrations varying from 4-10 at.%, controlled only by the deposition potential. We demonstrate control over magnetic Co oxide nano-precipitate formation in the nanowires via the Cu concentration. The different magnetic behavior of the Co oxide nano-precipitates indicates the potential of ZnCoO for magnetic sensor applications.Comment: 5 pages, 5 figure

Actin-based propulsion of spatially extended objects

We propose a mathematical model of the actin-based propulsion of spatially extended obstacles. It starts from the properties of individual actin filaments and includes transient attachment to the obstacle, polymerization as well as cross-linking. Two particular geometries are discussed, which apply to the motion of protein-coated beads in a cell-like medium and the leading edge of a cell protrusion, respectively. The model gives rise to both steady and saltatory movement of beads and can explain the experimentally observed transitions of the dynamic regime with changing bead radius and protein surface density. Several spatiotemporal patterns are obtained with a soft obstacle under tension, including the experimentally observed spontaneous emergence of lateral traveling waves in crawling cells. Thus, we suggest a unifying mechanism for systems that are currently described by differential concepts

NANOWIRES AND NANOTUBES PREPARED USING ION TRACK MEMBRANES AS TEMPLATES

The template method proved itself to be an interesting approach for preparing structures with low dimensionality. The paper presents a review of our results using a particular case of the method namely the preparation of nanowires and nanotubes using ion track membranes as templates. Thus, metallic or semiconductor nanowires were prepared using electrochemical deposition in membranes with cylindrical or conical pores. Similar membranes were used to prepare tubules with different morphologies using electroless deposition. In the paper the main advantages of the method will be presented

OPTICAL AND PHOTOCATALYTIC PROPERTIES OF ELECTROSPUN ZnO FIBERS

ZnO nanofibers were obtained by electrospinning a solution of zinc acetate dihydrate and polyvinylpyrrolidone in N,N-dimethylformamide, followed by calcination at 500, 650 or 800 °C for 1 h. X-ray diffraction, selected area electron diffraction, scanning electron microscopy, transmission electron microscopy, reflectance spectroscopy and photoluminescence spectroscopy were used for the characterization of the resulting fibers. The thermally treated samples exhibit ZnO single phase with polycrystalline hexagonal structure. The morphological investigation revealed an accentuated contraction process during calcination, as well as the increase of the crystallite size and the appearance of a breaking tendency with the calcination temperature enhancement. Both UV and Visible emissions under excitation at 350 nm were showed by the optical studies, which also led to band gap values slightly lower than those reported for similar one-dimensional nanostructures. In order to assess the photocatalytic activity of ZnO fibers, the photodegradation of methylene blue in aqueous medium (10 -3 M) under UV irradiation (368 nm) was analyzed

Sequential Deposition Of Multisegment Nanowires

Electrochemical replication of nanoporous membranes represents a facile approach towards the fabrication of nanostructures with tailored properties. By the template method we prepared multisegment nanowires with tailored structure. The first step of the process was the fabrication of the nanoporous template by swift heavy ion irradiation and subsequent selective etching of the ion track. The next step was to fill the pores with the desired combination of materials. In this manner, by sequential electrodeposition steps of metal and semiconductor we prepared Ni -CdTe and Ni -ZnO -Ni nanowires

Metal Oxide Nanowires as Building Blocks for Optoelectronic Devices

Metal oxide nanowires have become the new building blocks for the next generation optoelectronic devices due to their specific features such as quantum confinement and high aspect ratio. Thus, they can be integrated as active components in diodes, field effect transistors, photodetectors, sensors, solar cells and so on. ZnO, a n-type semiconductor with a direct wide band gap (3.3 eV) and CuO, a p-type semiconductor with a narrow band gap (1.2–1.5 eV), are two metal oxides which were recently in the spotlight of the researchers for applications in the optoelectronic devices area. Therefore, in this chapter we focused on ZnO and CuO nanowires, the metal oxides nanowire arrays being prepared by straightforward wet and dry methods. Further, in order to emphasize their intrinsic transport properties, lithographic and thin films deposition techniques were used to integrate single ZnO and CuO nanowires into diodes and field effect transistors

Postoperative complicated appendectomy revealing Crohn’s disease in a pediatric patient

Granulomatous appendicitis is a very rare entity in children. It is related to Crohn’s disease in only 5-10% of the cases. The diagnosis of Crohn’s disease is a real challenge in the pediatric population, especially when its initial manifestation is acute appendicitis. Herein, we present a 13-year-old boy admitted for acute appendicitis. The histopathological examination was conclusive for acute granulomatous appendicitis. The development of an entero-cutaneous fistula has complicated the postoperative evolution. The failure of the conservative management required ileocecal resection. The pathological examination revealed Crohn’s disease. The one-year follow-up on the patient din not reveal any complications. We strongly support the importance of the histopathological examination of the entirely removed appendix. Careful assessment of granulomatous appendicitis is needed in order to establish its possible etiology and to initiate the adequate treatment