MTP: A Movie Transmission Protocol for Multimedia Applications

Typical color video adapters of today's PCs and workstationsuse 8 bits per pixel as an index into the color lookup table (CLUT). Full color pictures and movies have to be reduced to 256 colors. In order to avoid false colors between two frames of a digital movie, a novel technique for computing the CLUT's is proposed: A subset of the CLUT entries is reserved for new colors of the next frame. The paper presents an algorithm for the gradual adaption of the color lookup table during the transmission of a movie. First experience is reported in the framework of the XMovie project

3D X-ray Microtomography Volume Correlation to Study Fatigue Crack Growth

International audienceGlobal digital volume correlation is used to analyze a series of computed tomography images of a nodular graphite cast iron specimen subjected in situ to a fatigue test. From the obtained displacement field, a specific procedure is implemented to extract stress intensity factors all along the crack front. The proposed methodology allows one to measure key parameters in fatigue crack propagation directly from 3D images

Podosome-Driven Defect Development in Lamellar Bone under the Conditions of Senile Osteoporosis Observed at the Nanometer Scale

The degradation mechanism of human trabecular bone harvested from the central part of the femoral head of a patient with a fragility fracture of the femoral neck under conditions of senile osteoporosis was investigated by high-resolution electron microscopy. As evidenced by light microscopy, there is a disturbance of bone metabolism leading to severe and irreparable damages to the bone structure. These defects are evoked by osteoclasts and thus podosome activity. Podosomes create typical pit marks and holes of about 300-400 nm in diameter on the bone surface. Detailed analysis of the stress field caused by the podosomes in the extracellular bone matrix was performed. The calculations yielded maximum stress in the range of few megapascals resulting in formation of microcracks around the podosomes. Disintegration of hydroxyapatite and free lying collagen fibrils were observed at the edges of the plywood structure of the bone lamella. At the ultimate state, the disintegration of the mineralized collagen fibrils to a gelatinous matrix comes along with a delamination of the apatite nanoplatelets resulting in a brittle, porous bone structure. The nanoplatelets aggregate to big hydroxyapatite plates with a size of up to 10 x 20 μm2. The enhanced plate growth can be explained by the interaction of two mechanisms in the ruffled border zone: the accumulation of delaminated hydroxyapatite nanoplatelets near clusters of podosomes and the accelerated nucleation and random growth of HAP nanoplatelets due to a nonsufficient concentration of process-directing carboxylated osteocalcin cOC. © 2021 The Authors. Published by American Chemical Society

Economic Analysis of Knowledge: The History of Thought and the Central Themes

Following the development of knowledge economies, there has been a rapid expansion of economic analysis of knowledge, both in the context of technological knowledge in particular and the decision theory in general. This paper surveys this literature by identifying the main themes and contributions and outlines the future prospects of the discipline. The wide scope of knowledge related questions in terms of applicability and alternative approaches has led to the fragmentation of research. Nevertheless, one can identify a continuing tradition which analyses various aspects of the generation, dissemination and use of knowledge in the economy

Cellular nanoparticle delivery by G-protein coupled receptors

Considering the significant benefits that site-specific drug therapy offers, in this work, the potential of G-protein-coupled receptors (GPCRs) as candidates for a new class of targets in the field of drug targeting was investigated. In order to evaluate this potential at the cellular level, nanoparticles were conjugated with specific ligands for the human neuropeptide Y (hNPY) Y1 receptor and characterized according to their affinity to cells expressing this receptor. A second objective was to explore whether GPCRs provide a portal for nanoparticle delivery into cells, since GPCRs are known to internalize after agonist binding. GPCRs represent the largest class of receptors in the human genome and have, therefore, been a key area of focus in drug research for several decades. Consequently, we know a number of specifically binding ligands as well as the organ distribution of many GPCRs. This makes GPCRs extremely interesting candidates for nanoparticle drug targeting. As model colloid, quantum dots (QDs), semiconductor nanocrystals have been used. Methods for their fabrication were developed and the nanoparticles subsequently were surface-modified by several techniques using poly(ethylene glycol) (PEG) and PEGylated phospholipids. The resulting surface-modified nanocrystals were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM) and asymmetrical flow field-flow fractionation (AF4) as well as by photometric measurements. Additionally, the particles potential as traceable model nanoparticles for cellular studies was evaluated. For the investigation of targeted uptake of nanoparticles by GPCRs, ligands for the human NPY Y1-receptor were attached to QDs. The particles were tested using Y1-receptor expressing (MCF-7, SK-N-MC) and Y1-receptor lacking (MDA) human cell lines. Confocal laser scanning microscopy revealed specific binding uptake of the particles when they were linked with agonistic peptides for the Y1-receptor. In contrast, when an antagonistic ligand was conjugated with the particles, binding cellular uptake was strongly reduced. Flow-cytometric investigations showed that the ligand-modified QDs strongly and specifically bind to the cells and a multiligand binding of the QDs to the cells was suggested. Finally, the uptake of the agonist-modified QDs was compared with a fluorescent NPY and QDs modified with poly(ethylene imine)

The Measurement of Ranks and the Laws of Iterated Contraction

Ranking theory delivers an account of iterated contraction; each ranking function induces a specific iterated contraction behavior. The paper shows how to reconstruct a ranking function from its iterated contraction behavior uniquely up to multiplicative constant and thus how to measure ranks on a ratio scale. Thereby, it also shows how to completely axiomatize that behavior. The complete set of laws of iterated contraction it specifies amend the laws hitherto discussed in the literature

Phonon interaction of single excitons and biexcitons

The exciton-phonon coupling of a single zero-dimensional exciton is studied in epitaxially grown CdSe/Zn1−xCdxSe quantum dot structures by analyzing its linewidth and phonon-assisted recombination. The single excitons do not couple to only a single phonon mode, but to a distribution of phonons, here consisting of the zone-center ZnSe longitudinal optic (LO) phonon and of mixed modes with an energy statistics centered between the ZnSe and CdSe LO phonon. Both exciton and corresponding biexciton reveal LO-phonon replica intensities of ∼3% of the respective zero-phonon emission. These similar LO-phonon coupling strengths are evidence of a reduced polarity of the exciton states within the biexciton as the result of exciton-exciton correlation