310 research outputs found
Studies of irradiated AMS H35 CMOS detectors for the ATLAS tracker upgrade
Silicon detectors based on the HV-CMOS technology are being investigated as
possible candidate for the outer layers of the ATLAS pixel detector for the
High Luminosity LHC. In this framework the H35Demo ASIC has been produced in
the 350 nm AMS technology (H35). The H35Demo chip has a large area () and includes four different pixel matrices and
three test structures. In this paper the radiation hardness properties, in
particular the evolution of the depletion region with fluence is studied using
edge-TCT on test structures. Measurements on the test structures from chips
with different substrate resistivity are shown for non irradiated and
irradiated devices up to a cumulative fluence of
Spatio-temporal analysis of blood perfusion by imaging photoplethysmography
Imaging photoplethysmography (iPPG) has attracted much attention over the last years. The vast majority of works focuses on methods to reliably extract the heart rate from videos. Only a few works addressed iPPGs ability to exploit spatio-temporal perfusion pattern to derive further diagnostic statements.
This work directs at the spatio-temporal analysis of blood perfusion from videos. We present a novel algorithm that bases on the two-dimensional representation of the blood pulsation (perfusion map). The basic idea behind the proposed algorithm consists of a pairwise estimation of time delays between photoplethysmographic signals of spatially separated regions. The probabilistic approach yields a parameter denoted as perfusion speed. We compare the perfusion speed versus two parameters, which assess the strength of blood pulsation (perfusion strength and signal to noise ratio).
Preliminary results using video data with different physiological stimuli (cold pressure test, cold face test) show that all measures are in fluenced by those stimuli (some of them with statistical certainty). The perfusion speed turned out to be more sensitive than the other measures in some cases. However, our results also show that the intraindividual stability and interindividual comparability of all used measures remain critical points.
This work proves the general feasibility of employing the perfusion speed as novel iPPG quantity. Future studies will address open points like the handling of ballistocardiographic effects and will try to deepen the understanding of the predominant physiological mechanisms and their relation to the algorithmic performance
Index-aware learning of circuits
Electrical circuits are present in a variety of technologies, making their
design an important part of computer aided engineering. The growing number of
tunable parameters that affect the final design leads to a need for new
approaches of quantifying their impact. Machine learning may play a key role in
this regard, however current approaches often make suboptimal use of existing
knowledge about the system at hand. In terms of circuits, their description via
modified nodal analysis is well-understood. This particular formulation leads
to systems of differential-algebraic equations (DAEs) which bring with them a
number of peculiarities, e.g. hidden constraints that the solution needs to
fulfill. We aim to use the recently introduced dissection concept for DAEs that
can decouple a given system into ordinary differential equations, only
depending on differential variables, and purely algebraic equations that
describe the relations between differential and algebraic variables. The idea
then is to only learn the differential variables and reconstruct the algebraic
ones using the relations from the decoupling. This approach guarantees that the
algebraic constraints are fulfilled up to the accuracy of the nonlinear system
solver, which represents the main benefit highlighted in this article.Comment: 15 pages, 15 figure
2,2,2-Trifluoro-1-[3-(2,2,2-trifluoroÂacetÂyl)azulen-1-yl]ethanone
There are two molÂecules in the asymmetric unit of the title compound, C14H6F6O2, in which the azulene systems possess an almost planar geometry with maximum deviations of 0.0438 (15) and 0.0396 (14) Å. Besides intra- and interÂmolecular C—H⋯O and C—H⋯F interÂactions, the structure displays three F⋯F contacts [2.793 (2), 2.8820 (17) and 2.9181 (16) Å]. Furthermore, a characteristic azulene Ï€-stacking is observed with an alternating sequence of electron-rich five-membered rings and electron-deficient seven-membered rings [centroid–centroid distances = 3.5413 (12), 3.6847 (12), 3.5790 (12) and 3.7718 (12) Å]
Chemoprofiling as Breeding Tool for Pharmaceutical Use of Salix
Willow bark is traditionally used for pharmaceutical purposes. Evaluation is so far based on the salicylate content, however, health promoting effects of extracts might be attributed to the interaction of those salicylates with other compounds, which support and complement their action. So far, only S. purpurea, S. daphnoides, and S. fragilis are included in pharmaceutical extracts. Crossing with other species could result in a more diverse secondary metabolite profile with higher pharmacological value. With the help of targeted inter- and intraspecific crossing, new chemotypes were generated, whereby nine different Salix genotypes (S. alba, S. daphnoides, S. humboldtiana, S. lasiandra, S. nigra, S. pentandra, S. purpurea, S. x rubens, S. viminalis) were included in the study. Based on substances known for their health promoting potential and characteristic for Salix (selected phenolic compounds including salicylates), a targeted metabolomics analysis and clustering of 92 generated Salix clones was performed revealing four different cluster/chemoprofiles. In more specific, one group is formed by S. daphnoides clones and inter- and intraspecific hybrids, a second group by S. viminalis clones and inter- and intraspecific hybrids, a third group generally formed by S. alba, S. pentandra, S. x rubens, and S. lasiandra clones and hybrids, and a fourth group by S. purpurea clones and inter- and intraspecific hybrids. Clustering on the basis of the selected phenolic compounds can be used for identifying Salix clones with a different compound profile. New combinations of secondary plant metabolites offer the chance to identify Salix crosses with improved effects on human health.Peer Reviewe
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