Ortsgenaue Ablagerung von Aminosäurepartikeln für die kombinatorische Synthese von Peptidarrays auf einen Chip

Die ortsgenaue Ablagerung von Aminosäurepartikeln auf einen Chip liegt der parallelen kombinatorischen Synthese von Peptidarrays mit Spotdichten oberhalb von 104 cm-2 zugrunde. Es wurden drei miteinander wechselwirkende Bereiche betrachtet: Die Anpassung der elektrischen Eigenschaften der Partikel, der Partikeltransport zur Chipoberfläche und die Erzeugung von selektiv wirkenden Kräften auf der Chipoberfläche. Die q/m-Werte der Partikel sowie deren Ladungsverteilung wurden mit Hilfe verschiedener Methoden gemessen. Die triboelektrische Aufladung der Partikel beim Kontakt mit Plexiglas und die Abhängigkeit des q/m-Wertes vom Druckluftstrom wurden ebenfalls untersucht. Als Übertragungsmethoden wurden die ortsgenaue Ablagerung der Partikel aus dem Aerosol, die selektive Desorption von Aminosäurepartikeln und die so genannte Positionierung der Partikel evaluiert. Ein qualitatives Modell der Übertragungsprozesse in der Aerosolkammer wurde erstellt. Die kontaminationsfreie Ablagerung von Partikeln mit einem mittleren Durchmesser von 10 µm aus dem Aerosol kann an Potentialflächen mit einem Raster bis zu 50 µm und bei Spannungen oberhalb von 30 V erfolgen. Bei einer Vergrößerung der elektrischen Felder auf der Chipoberfläche wird die Ablagerungsselektivität vergrößert. Auf Basis der Übertragungsmethoden wurde ein Anforderungsprofil an das Chipdesign erstellt. Selektiv wirkende elektrische Kräfte wurden mit Hilfe eines CMOS-Chips (AMIS C07M I2T100 Prozess) erzeugt. Die Stromspannungskennlinien der Hochspannungstransistoren mit einer minimalen Breite von 1,8 - 2,0 µm wurden gemessen und simuliert. Es wurde die Möglichkeit zur Integration von Photodioden auf einem CMOS-Chip für optische Nachweise bei der Anwendung der Peptidarrays betrachtet

Die Botschaft von LUCA — der letzte universelle gemeinsame Vorfahre

The standard genetic code is the only reliable information about the first living cell on Earth called the last universal common ancestor – LUCA. The central mystery of the genetic code is the assignment of the canonical amino acids to the codons – base triplets. Simple and uniform combinatorial rules indicate that the standard genetic code arose during the fusion of four primordial single base-pair codes

Measurement of event-shape observables in Z→ℓ+ℓ− events in pp collisions at √ s=7 TeV with the ATLAS detector at the LHC

Event-shape observables measured using charged particles in inclusive $Z$-boson events are presented, using the electron and muon decay modes of the $Z$ bosons. The measurements are based on an integrated luminosity of $1.1 {\rm fb}^{-1}$ of proton--proton collisions recorded by the ATLAS detector at the LHC at a centre-of-mass energy $\sqrt{s}=7$ TeV. Charged-particle distributions, excluding the lepton--antilepton pair from the $Z$-boson decay, are measured in different ranges of transverse momentum of the $Z$ boson. Distributions include multiplicity, scalar sum of transverse momenta, beam thrust, transverse thrust, spherocity, and $\mathcal{F}$-parameter, which are in particular sensitive to properties of the underlying event at small values of the $Z$-boson transverse momentum. The Sherpa event generator shows larger deviations from the measured observables than Pythia8 and Herwig7. Typically, all three Monte Carlo generators provide predictions that are in better agreement with the data at high $Z$-boson transverse momenta than at low $Z$-boson transverse momenta and for the observables that are less sensitive to the number of charged particles in the event.Comment: 36 pages plus author list + cover page (54 pages total), 14 figures, 4 tables, submitted to EPJC, All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2014-0

Charged-particle multiplicities in pp interactions at root s=900 GeV measured with the ATLAS detector at the LHC ATLAS Collaboration

The first measurements from proton–proton collisions recorded with the ATLAS detector at the LHC are presented. Data were collected in December 2009 using a minimum-bias trigger during collisions at a centre-of-mass energy of 900 GeV. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity, and the relationship between mean transverse momentum and charged-particle multiplicity are measured for events with at least one charged particle in the kinematic range |η|500 MeVpT>500 MeV. The measurements are compared to Monte Carlo models of proton–proton collisions and to results from other experiments at the same centre-of-mass energy. The charged-particle multiplicity per event and unit of pseudorapidity at η=0η=0 is measured to be 1.333±0.003(stat.)±0.040(syst.)1.333±0.003(stat.)±0.040(syst.), which is 5–15% higher than the Monte Carlo models predict

Selecting the best performing fire weather indices for Austrian ecoregions

The interpretation and communication of fire danger warning levels based on fire weather index values are critical for fire management activities. A number of different indices have been developed for various environmental conditions, and many of them are currently applied in operational warning systems. To select an appropriate combination of such indices to work in different ecoregions in mountainous, hilly and flat terrain is challenging. This study analyses the performance of a total of 22 fire weather indices and two raw meteorological variables to predict wildfire occurrence for different ecological regions of Austria with respect to the different characteristics in climate and fire regimes. A median-based linear model was built based on percentile results on fire days and non-fire days to get quantifiable measures of index performance using slope and intercept of an index on fire days. We highlight the finding that one single index is not optimal for all Austrian regions in both summer and winter fire seasons. The summer season (May-November) shows that the Canadian build-up index, the Keetch Byram Drought Index and the mean daily temperature have the best performance; in the winter season (December-April), the M68dwd is the best performing index. It is shown that the index performance on fire days where larger fires appeared is better and that the uncertainties related to the location of the meteorological station can influence the overall results. A proposal for the selection of the best performing fire weather indices for each Austrian ecoregion is made