Jožef Stefan Institute

About: Jožef Stefan Institute is a facility organization based out in Ljubljana, Slovenia. It is known for research contribution in the topics: Liquid crystal & Dielectric. The organization has 3828 authors who have published 12614 publications receiving 291025 citations.

Trigger and aperture of the surface detector array of the pierre auger observatory

Abstract: The surface detector array of the Pierre Auger Observatory consists of 1600 water-Cherenkov detectors, for the study of extensive air showers (EAS) generated by ultra-high-energy cosmic rays. We describe the trigger hierarchy, from the identification of candidate showers at the level of a single detector, amongst a large background (mainly random single cosmic ray muons), up to the selection of real events and the rejection of random coincidences. Such trigger makes the surface detector array fully efficient for the detection of EAS with energy above 3 x 10(18) eV, for all zenith angles between 0 degrees and 60 degrees, independently of the position of the impact point and of the mass of the primary particle. In these range of energies and angles, the exposure of the surface array can be determined purely on the basis of the geometrical acceptance. (C) 2009 Elsevier B.V. All rights reserved.

Spontaneous Growth of Superstructure α-Fe2O3 Nanowire and Nanobelt Arrays in Reactive Oxygen Plasma

Abstract: One-dimensional a-Fe2O3 is a promising nanomaterial for advanced applications in catalysis and water splitting, environmental protection, sensors, dye solar cells, magnetic storage media, bioprocessing, and controlled drug delivery and detection, especially as carriers of antigens for prion detection and PCR manipulation. a-Fe2O3 nanowires have been successfully synthesized by various methods based on templates, hydrothermal conditions, sol–gel-mediated reactions, solvothermal conditions, gas decomposition, direct thermal oxidation (in a gas atmosphere of CO2, SO2, O2, and NO2), [7] chemical vapor deposition (CVD), and plasmaenhanced chemical vapor deposition (PECVD). The methods based on direct thermal oxidation, gas decomposition, and CVD reported to date require long synthesis times and high temperatures and therefore limit the efficiency of oxide nanowire synthesis. The application and commercialization of nanowires or nanobelts requires simple synthetic methods that can be scaled for both large areas and large quantities. Recently, we discovered a new universal method for the synthesis of transition metal oxide nanowires and nanobelts by direct plasma oxidation of bulk materials. It has been successfully applied for the rapid synthesis of high-density niobium oxide nanowires. In this process, there is no

Local Polarization Distribution and Edwards-Anderson Order Parameter of Relaxor Ferroelectrics

Abstract: The temperature dependence of the Edwards-Anderson order parameter ${q}_{\mathrm{EA}}$ and the local polarization distribution function $W(\stackrel{\ensuremath{\rightarrow}}{p})$ have been determined in a PMN single crystal via 2D ${}^{93}\mathrm{Nb}$ NMR. A glasslike freezing of reorientable polar clusters occurs in the temperature range of the diffuse relaxor transition, whereas the NMR spectra corresponding to pinned nanodomains do not change with temperature. The obtained form of $W(\stackrel{\ensuremath{\rightarrow}}{p})$ as well as the temperature dependence of ${q}_{\mathrm{EA}}$ and the nonlinear dielectric susceptibility can be well described by a newly proposed spherical random bond--random field model of relaxor ferroelectrics.

Similarities and Specificities of Fungal Keratinolytic Proteases: Comparison of Keratinases of Paecilomyces marquandii and Doratomyces microsporus to Some Known Proteases

Abstract: Based on previous screening for keratinolytic nonpathogenic fungi, Paecilomyces marquandii and Doratomyces microsporus were selected for production of potent keratinases. The enzymes were purified and their main biochemical characteristics were determined (molecular masses, optimal temperature and pH for keratinolytic activity, N-terminal amino acid sequences). Studies of substrate specificity revealed that skin constituents, such as the stratum corneum, and appendages such as nail but not hair, feather, and wool were efficiently hydrolyzed by the P. marquandii keratinase and about 40% less by the D. microsporus keratinase. Hydrolysis of keratin could be increased by the presence of reducing agents. The catalytic properties of the keratinases were studied and compared to those of some known commercial proteases. The profile of the oxidized insulin B-chain digestion revealed that both keratinases, like proteinase K but not subtilisin, trypsin, or elastase, possess broad cleavage specificity with a preference for aromatic and nonpolar amino acid residues at the P-1 position. Kinetic studies were performed on a synthetic substrate, succinyl-Ala-Ala-Pro-Phe-p-nitroanilide. The keratinase of P. marquandii exhibited the lowest Km among microbial keratinases reported in the literature, and its catalytic efficiency was high in comparison to that of D. microsporus keratinase and proteinase K. All three keratinolytic enzymes, the keratinases of P. marquandii and D. microsporus as well as proteinase K, were significantly more active on keratin than subtilisin, trypsin, elastase, chymotrypsin, or collagenase.