8,888 research outputs found
Prognostic value of troponins in acute coronary syndrome depends upon patient age
Peer reviewedPostprin
Development of a triple GEM UV-photon detector operated in pure CF4 for the PHENIX experiment
Results obtained with a triple GEM detector operated in pure CF4 with and
without a reflective CsI photocathode are presented. The detector operates in a
stable mode at gains up to 10^4. A deviation from exponential growth starts to
develop when the total charge exceeds ~ 4 10^6 e leading to gain saturation
when the total charge is ~ 2 10^7 e and making the structure relatively robust
against discharges. No aging effects are observed in the GEM foils after a
total accumulated charge of ~ 10 mC/cm^2 at the anode. The ion back-flow
current to the reflective photocathode is comparable to the electron current to
the anode. However, no significant degradation of the CsI photocathode is
observed for a total ion back-flow charge of ~ 7 mC/cm^2.Comment: 14 pages, 11 figures, Submitted to NIM
Conformational Mechanics of Polymer Adsorption Transitions at Attractive Substrates
Conformational phases of a semiflexible off-lattice homopolymer model near an
attractive substrate are investigated by means of multicanonical computer
simulations. In our polymer-substrate model, nonbonded pairs of monomers as
well as monomers and the substrate interact via attractive van der Waals
forces. To characterize conformational phases of this hybrid system, we analyze
thermal fluctuations of energetic and structural quantities, as well as
adequate docking parameters. Introducing a solvent parameter related to the
strength of the surface attraction, we construct and discuss the
solubility-temperature phase diagram. Apart from the main phases of adsorbed
and desorbed conformations, we identify several other phase transitions such as
the freezing transition between energy-dominated crystalline low-temperature
structures and globular entropy-dominated conformations.Comment: 13 pages, 15 figure
Specificity characteristics of 7 commercial creatinine measurement procedures by enzymatic and jaffe method principles
Journal ArticleStandardized calibration does not change a creatinine measurement procedure?s susceptibility to potentially interfering substances
Disordered quantum wires: microscopic origins of the DMPK theory and Ohm's law
We study the electronic transport properties of the Anderson model on a
strip, modeling a quasi one-dimensional disordered quantum wire. In the
literature, the standard description of such wires is via random matrix theory
(RMT). Our objective is to firmly relate this theory to a microscopic model. We
correct and extend previous work (arXiv:0912.1574) on the same topic. In
particular, we obtain through a physically motivated scaling limit an ensemble
of random matrices that is close to, but not identical to the standard transfer
matrix ensembles (sometimes called TOE, TUE), corresponding to the Dyson
symmetry classes \beta=1,2. In the \beta=2 class, the resulting conductance is
the same as the one from the ideal ensemble, i.e.\ from TUE. In the \beta=1
class, we find a deviation from TOE. It remains to be seen whether or not this
deviation vanishes in a thick-wire limit, which is the experimentally relevant
regime. For the ideal ensembles, we also prove Ohm's law for all symmetry
classes, making mathematically precise a moment expansion by Mello and Stone.
This proof bypasses the explicit but intricate solution methods that underlie
most previous results.Comment: Corrects and extends arXiv:0912.157
SARS-CoV-2 structural features may explain limited neutralizing-antibody responses.
Neutralizing antibody responses of SARS-CoV-2-infected patients may be low and of short duration. We propose here that coronaviruses employ a structural strategy to avoid strong and enduring antibody responses. Other viruses induce optimal and long-lived neutralizing antibody responses, thanks to 20 or more repetitive, rigid antigenic epitopes, spaced by 5–10 nm, present on the viral surface. Such arrays of repetitive and highly organized structures are recognized by the immune system as pathogen-associated structural patterns (PASPs), which are characteristic for pathogen surfaces. In contrast, coronaviruses are large particles with long spikes (S protein) embedded in a fluid membrane. Therefore, the neutralizing epitopes (which are on the S protein) are loosely “floating” and widely spaced by an average of about 25 nm. Consequently, recruitment of complement is poor and stimulation of B cells remains suboptimal, offering an explanation for the inefficient and short-lived neutralizing antibody responses
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