3,648 research outputs found
Determination of the inhibitory effects of microdiets used in routine commercial feeding protocols on protease activities of Argyrosomus regius (Asso, 1801) larva
The aim of this study was to determine the inhibitory effects of feed ingredients on protease activities of Argyrosomus regius larvae using in vitro techniques. A. regius larvae fed on a commercial feeding procedure were sampled thirteen times, during the sampling period (from 3 to 32 days after hatching (DAH)). The differences observed in protease activities of meagre larvae during the sampling period were statistically significant (p<0.05). The lowest and highest protease activities of meagre larvae were 5.95±0.6 U/mg protein (15 DAH) and 211.21±12.56 U/mg protein (7 DAH), respectively. The fluctuations observed in protease activities of A. regius larvae were between 10 DAH and 32 DAH. Commercial diets such as Orange Start-S (100-200µ), Orange Start-L (200-300µ), Orange Nurse-XS (300-500µ), Orange Grow-S (300-500µ) and Orange Grow-L (500-800µ) caused the inhibitions on protease activities in meagre larvae to range from 16 to 32 DAH. The results point to the inadequacy of commercial diets such as Orange Grow-S, Orange Grow-L and suitability of Orange Start-S, Orange Start-L, Orange Nurse-XS for feeding meagre larvae during the weaning stage. For the mass production of quality juveniles, future studies should take into account the inhibitory effects of commercial diets and feed ingredients before the manufacturing process. A similar approach may be used to determine the most suitable commercial diets for use during the weaning stages of marine fish larvae to obtain the best growth performance and survival
Peptide-Mediated Constructs of Quantum Dot Nanocomposites for Enzymatic Control of Nonradiative Energy Transfer
Cataloged from PDF version of article.A bottom-up approach for constructing colloidal semiconductor quantum dot (QDot) nanocomposites that facilitate nonradiative Forster-type resonance energy transfer (FRET) using polyelectrolyte peptides was proposed and realized. The electrostatic interaction of these polypeptides with altering chain lengths was probed for thermodynamic, structural, and morphological aspects. The resulting nanocomposite film was successfully cut with the protease by digesting the biomimetic peptide layer upon which the QDot assembly was constructed. The ability to control photoluminescence decay lifetime was demonstrated by proteolytic enzyme activity, opening up new possibilities for biosensor applications
CP conserving constraints on Supersymmetric CP violation in the MSSM
We address the following question. Take the Constrained Minimal Supersymmetric Standard Model (CMSSM) with the two CP violating SUSY phases different from zero, and neglect the bound coming from the electric dipole moment of the neutron (EDM): is it possible to fully account for CP violation in the kaon and B systems using only the SUSY contributions with vanishing CKM phase? We show that the constraint, though CP conserving, forces a negative answer to the above question. This implies that, even in the regions of the CMSSM where a cancellation of different contributions to the EDM allows for large SUSY phases, it is not possible to exploit the SUSY phases to fully account for observable CP violation. Hence to have sizeable SUSY contributions to CP violation, one needs new flavor structures in the sfermion mass matrices beyond the usual CKM matrix
Quantum efficiency enhancement in film by making nanoparticles of polyfluorene
Cataloged from PDF version of article.We report on conjugated polymer nanoparticles of polyfluorene that were formed to exhibit higher fluorescence quantum efficiency in film (68%) and reduce undesired emission peak wavelength shifts in film (by 20 nm), compared to the solid-state polymer thin film made directly out of the same polymer solution without forming nanoparticles. Using the facile reprecipitation method, solutions of poly[9,9-dihexyl-9H-fluorene] in THF were added at different volume ratios to obtain different size distributions of nanoparticle dispersions in water. This allowed us to control the sizedependent optical emission of our polyfluorene nanoparticles. Such organic nanoparticles hold great promise for use as efficient emitters in optoelectronic device applications. (C) 2008 Optical Society of America
Non-radiative resonance energy transfer in bi-polymer nanoparticles of fluorescent conjugated polymers
Cataloged from PDF version of article.his work demonstrates the comparative studies of non-radiative resonance energy transfer in bi-polymer nanoparticles based on fluorescent conjugated polymers. For this purpose, poly[(9,9-dihexylfluorene) (PF) as a donor (D) and poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) as an acceptor (A) have been utilized, from which four different bi-polymer nanoparticle systems are designed and synthesized. Both, steady-state fluorescence spectra and time-resolved fluorescence measurements indicate varying energy transfer efficiencies from the host polymer PF to the acceptor polymer MEH-PPV depending on the D-A distances and structural properties of the nanoparticles. The first approach involves the preparation of PF and MEH-PPV nanoparticles separately and mixing them at a certain ratio. In the second approach, first PF and MEH-PPV solutions are mixed prior to nanoparticle formation and then nanoparticles are prepared from the mixture. Third and fourth approaches involve the sequential nanoparticle preparation. In the former, nanoparticles are prepared to have PF as a core and MEH-PPV as a shell. The latter is the reverse of the third in which the core is MEH-PPV and the shell is PF. The highest energy transfer efficiency recorded to be 35% is obtained from the last system, in which a PF layer is sequentially formed on MEH-PPV NPs. © 2010 Optical Society of America
Generalized Theory of Forster-Type Nonradiative Energy Transfer in Nanostructures with Mixed Dimensionality
Cataloged from PDF version of article.Forster-type nonradiative energy transfer (NRET) is widely used, especially utilizing nanostructures in different combinations and configurations. However, the existing well-accepted Forster theory is only for the case of a single particle serving as a donor together with another particle serving as an acceptor. There are also other special cases previously studied; however, there is no complete picture and unified understanding. Therefore, there is a strong need for a complete theory that models Forster-type NRET for the cases of mixed dimensionality including all combinations and configurations. We report a generalized theory for the Forster-type, NRET, which includes the derivation of the effective dielectric function due to the donor in different confinement geometries and the derivation of transfer rates distance dependencies due to the acceptor in different confinement geometries, resulting in a complete picture and understanding of the mixed dimensionality
Information-Theoretic Active Learning for Content-Based Image Retrieval
We propose Information-Theoretic Active Learning (ITAL), a novel batch-mode
active learning method for binary classification, and apply it for acquiring
meaningful user feedback in the context of content-based image retrieval.
Instead of combining different heuristics such as uncertainty, diversity, or
density, our method is based on maximizing the mutual information between the
predicted relevance of the images and the expected user feedback regarding the
selected batch. We propose suitable approximations to this computationally
demanding problem and also integrate an explicit model of user behavior that
accounts for possible incorrect labels and unnameable instances. Furthermore,
our approach does not only take the structure of the data but also the expected
model output change caused by the user feedback into account. In contrast to
other methods, ITAL turns out to be highly flexible and provides
state-of-the-art performance across various datasets, such as MIRFLICKR and
ImageNet.Comment: GCPR 2018 paper (14 pages text + 2 pages references + 6 pages
appendix
Avoiding Bending in Case of Uniaxial Tension with Electromagnetic Forming
During electromagnetic forming, excessive bending of the specimen takes place due to
high velocities and inertia. We show that the excessive bending can be prevented by
optimizing the coil geometry in case of uniaxial tension. The process is simulated with
various coil geometries, and the resulting amount of bending is compared to the case of
standard Nakajima Test. The comparison shows that the bending can be minimised to
acceptable levels to be able to call the method a decent way of determining forming limits.
The results should be verified experimentally
Photogeneration of hot plasmonic electrons with metal nanocrystals: Quantum description and potential applications
Cataloged from PDF version of article.he paper reviews physical concepts related to the collective dynamics of plasmon excitations in metal nanocrystals with a focus on the photogeneration of energetic carriers. Using quantum linear response theory, we analyze the wave function of a plasmon in nanostructures of different sizes. Energetic carriers are efficiently generated in small nanocrystals due to the non-conservation of momentum of electrons in a confined nanoscale system. On the other hand, large nanocrystals and nanostructures, when driven by light, produce a relatively small number of carriers with large excitation energies. Another important factor is the polarization of the exciting light. Most efficient generation and injection of high-energy carriers can be realized when the optically induced electric current is along the smallest dimension of a nanostructure and also normal to its walls and, for efficient injection, the current should be normal to the collecting barrier. Other important properties and limitations: (1) intra-band transitions are preferable for generation of energetic electrons and dominate the absorption for relatively long wavelengths (approximately >600 nm), (2) inter-band transitions efficiently generate energetic holes and (3) the carrier-generation and absorption spectra can be significantly different. The described physical properties of metal nanocrystals are essential for a variety of potential applications utilizing hot plasmonic electrons including optoelectronic signal processing, photodetection, photocatalysis and solar-energy harvesting. © 2014 Elsevier Ltd
Neobisium yozgati n. sp., and N. anaisae n. sp. (Neobisiidae, Pseudoscorpiones), from Turkey and Macedonia (FYROM), respectively
Two new species of endemic and relict cave-dwellers of genus Neobisium Chamberlin, have been described from Turkey and Macedonia (FYROM), respectively. From its phenetically close congener, N. granulatum Beier, N. yozgati n. sp. (from Yozgat, Turkey) is distinguished in many important respects. In addition, N. anaisae n. sp. (from a cave in Krapa, FYROM) differs from its closest forms (N. korabense Ćurčić, N. ohridanum Hadži, and N. vladimirpantici Ćurčić) by many morphological characters and form of different body parts. Both species are illustrated, diagnosed, and thoroughly described. They both represent endemic and relict forms
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