Search results for "Icon"

NanoSIMS: insights into the organization of the proteinaceous scaffold within Hexactinellid sponge spicules.

2010

The giant basal spicules (GBS) from Monorhaphis chuni (Porifera [sponges], Hexactinellida) represent the largest biosilica structures on Earth and can reach lengths of 300 cm (diameter of 1.1 cm). The amorphous silica of the inorganic matrix is formed enzymatically by silicatein. During this process, the enzyme remains trapped inside the lamellar-organized spicules. In order to localize the organic silicatein scaffold, the inside of a lamella has been analyzed by nano-secondary ion mass spectrometry (NanoSIMS). It is shown that the GBSs are composed of around 245 concentrically arranged individual siliceous lamellae. These surround an internal siliceous axial cylinder. The lamellae adjacent…

A synthetic biology approach for the fabrication of functional (fluorescent magnetic) bioorganic–inorganic hybrid materials in sponge primmorphs

2020

During evolution, sponges (Porifera) have honed the genetic toolbox and biosynthetic mechanisms for the fabrication of siliceous skeletal components (spicules). Spicules carry a protein scaffold embedded within biogenic silica (biosilica) and feature an amazing range of optical, structural, and mechanical properties. Thus, it is tempting to explore the low-energy synthetic pathways of spiculogenesis for the fabrication of innovative hybrid materials. In this synthetic biology approach, the uptake of multifunctional nonbiogenic nanoparticles (fluorescent, superparamagnetic) by spicule-forming cells of bioreactor-cultivated sponge primmorphs provides access to spiculogenesis. The ingested nan…

Correlation between the Ionicity Character and the Charge Density in Semiconductors

1994

Using the electronic charge densities obtained by the empirical pseudopotential method for tetrahedrally bonded semiconductors, an ionicity scale is established that is in good agreement with the Phillips ionicity scale.

In vitro perception of low-contrast features in digital, film, and digitized dental radiographs: A receiver operating characteristic analysis

2005

Objective To compare experimentally the image quality of charged-coupled device (CCD)-based digital, flatbed scanner digitized, and dental film radiographs. Study design High-contrast standardized radiographs of an aluminum step wedge containing boreholes were obtained on dental radiographic film (F) and a CCD receptor (D). Digitization (S) was done with a flatbed scanner. Each radiograph was separated into 23 single images, 18 of which showed a dark spot. Thirty observers indicated their confidence on the visibility of the spots for a receiver operating characteristic (ROC) analysis. Results Mean Az values (area beneath the ROC curves) differed significantly (P < .05), being highest for D …

A high-resolution PET demonstrator using a silicon "magnifying glass".

2021

Abstract To assist ongoing investigations of the limits of the tradeoff between spatial resolution and noise in PET imaging, several PET instruments based on silicon-pad detectors have been developed. The latest is a segment of a dual-ring device to demonstrate that excellent reconstructed image resolution can be achieved with a scanner that uses highresolution detectors placed close to the object of interest or surrounding a small field-of-view in combination with detectors having modest resolution at larger radius. The outer ring of our demonstrator comprises conventional BGO block detectors scavenged from a clinical PET scanner and located at a 500 mm radius around a 50 mm diameter field…

Biopolitik am Computerbildschirm, in V. Borsò e M. Cometa (a cura) Die Kunst, das Leben zu Bewirtschaften. Biós zwischen Politik, Öikonomie und Äeste…

2013

Czytanie malarstwa romantycznego w szkole – aksjologiczny wymiar malarstwa Caspara Davida Friedricha

2015

Autorka szkicu podejmuje próbę diagnozy dzisiejszej sytuacji panującej w szkolnej metodyce „czytania” dzieł malarskich i kreśli idealną sytuację szkolnej egzegezy sztuk plastycznych, pozwalającą na wniknięcie w trzy wymiary dzieła: ontologiczny, semiotyczny i aksjologiczny. Jako przykład twórców, których obrazy dają szerokie możliwości interpretacyjne i umożliwiają odkrywanie metafizycznego wymiaru sztuki, podaje ikonografię romantyczną, a w niej malarstwo Kaspara Davida Friedricha. Zasadniczą część szkicu stanowi interpretacja dwóch obrazów niemieckiego artysty z motywem bohatera odwróconego plecami do widza. Pierwszy z nich to jedna z bardziej znanych jego kompozycji pt. Wędrowiec nad mor…

Coherent master equation for laser modelocking

2020

Modelocked lasers constitute the fundamental source of optically-coherent ultrashort-pulsed radiation, with huge impact in science and technology. Their modeling largely rests on the master equation (ME) approach introduced in 1975 by Hermann A. Haus. However, that description fails when the medium dynamics is fast and, ultimately, when light-matter quantum coherence is relevant. Here we set a rigorous and general ME framework, the coherent ME (CME), that overcomes both limitations. The CME predicts strong deviations from Haus ME, which we substantiate through an amplitude-modulated semiconductor laser experiment. Accounting for coherent effects, like the Risken-Nummedal-Graham-Haken multim…

Self-organization of active particles by quorum sensing rules

2018

Many microorganisms regulate their behaviour according to the density of neighbours. Such quorum sensing is important for the communication and organisation within bacterial populations. In contrast to living systems, where quorum sensing is determined by biochemical processes, the behaviour of synthetic active particles can be controlled by external fields. Accordingly they allow to investigate how variations of a density-dependent particle response affect their self-organisation. Here we experimentally and numerically demonstrate this concept using a suspension of light-activated active particles whose motility is individually controlled by an external feedback-loop, realised by a particl…

Gamma-ray position reconstruction in large lanthanum-halide crystals with SiPM readout: analytical vs. neural-network algorithms

2019

The main objective of this research was to achieve an excellent gamma-ray position reconstruction with very large monolithic scintillation crystals coupled to pixelated silicon photosensors. Analyzing the scintillation-light distribution measured along the SiPM-pixels one can get a sub-pixel accuracy for the position reconstruction. The quality of the latter depends on both the characteristics of the crystal-photosensor assembly, and the goodness of the algorithm used to reconstruct the gamma-ray hit location. We have carried out a systematic study for 511 keV gamma-rays using three different crystal thicknesses of 10 mm, 20 mm and 30 mm, all of them with planar geometry and a base size of …