1,867 research outputs found
Evaluation der potenziellen Regeneratschädigung bei der Kallusumformung nach Distraktionsosteogenese der Mandibula: Eine experimentelle Untersuchung am Tiermodell
Zusammenfassung: Ziel: Bei der Korrektur dreidimensionaler Deformitäten des Gesichtsskelettes mit der Distraktionsosteogenese werden Umformungsvorgänge des Regenerates einerseits als Bestandteil des Behandlungsplans, andererseits im Falle eines Verlustes der Kontrolle über den Distraktionsvektor vorgenommen. Die vorliegende Untersuchung hatte das Ziel, die Grenzen der Kallusmanipulation zu beurteilen. Dazu wurden die Auswirkungen komprimierender sowie dehnender Einflüsse am gleichen Regenerat untersucht. Material und Methode: Bei 15Beagle-Hunden wurde mit speziell angefertigten bidirektionalen Distraktoren eine lineare Distraktion von 10mm beidseits im Unterkieferwinkel vorgenommen. Der neu gebildete Kallus wurde in einem Schritt um 20° anguliert, was im vorliegenden Modell einer Verkürzung/Verlängerung von ca. 35% der Ausgangslänge des Regenerates gleichkommt. Die Position des Rotationszentrums erlaubte es, das Regenerat gleichzeitig zu komprimieren und zu dehnen. Die Auswirkungen dieser mechanischen Einflüsse auf die Ossifikation des Regenerates wurden nach 6 bzw. 13Wochen beurteilt und mit einer Kontrollgruppe, bei der lediglich eine lineare Distraktion durchgeführt worden war, verglichen. Ergebnisse: Die radiologischen und histologischen Untersuchungen ergaben keinen statisch signifikanten Unterschied zwischen dem komprimierten und gedehnten Regenerat. Es zeigten sich jedoch im gedehnten Sektor des Kallus Zonen unvollständiger Ossifikation nach 6-wöchiger Konsolidierungszeit. Unter stabilen Verhältnissen wurde die verzögerte Knochenheilung im weiteren Verlauf kompensiert und eine vollständige Ossifikation nach 13Wochen erreicht. Schlussfolgerung: Unter stabilen Verhältnissen kann ein durch Distraktion gebildetes frisches Regenerat in einem beträchtlichen Ausmaß umgeformt werden, ohne die knöcherne Heilung bleibend zu kompromittieren. Die Dehnung des Kallus kann jedoch zu einer Verzögerung oder dem Ausbleiben des Ossifikationsprozesses führen und sollte vermieden werden. Dies lässt sich durch eine Überkorrektur der Regeneratlänge oder durch eine graduelle Angulation während des Distraktionsvorgangs erreiche
Post test investigation of the bundle test ESBU-1. On temperature escalation in PWR fuel rod simulator bundles due to zircaloy/steam reaction
Temperature escalation in PWR fuel rod simulator bundles due to the zircaloy/steam reaction: post test investigations of bundle test ESBU-2A
Phylogeography of Japanese encephalitis virus:genotype is associated with climate
The circulation of vector-borne zoonotic viruses is largely determined by the overlap in the geographical distributions of virus-competent vectors and reservoir hosts. What is less clear are the factors influencing the distribution of virus-specific lineages. Japanese encephalitis virus (JEV) is the most important etiologic agent of epidemic encephalitis worldwide, and is primarily maintained between vertebrate reservoir hosts (avian and swine) and culicine mosquitoes. There are five genotypes of JEV: GI-V. In recent years, GI has displaced GIII as the dominant JEV genotype and GV has re-emerged after almost 60 years of undetected virus circulation. JEV is found throughout most of Asia, extending from maritime Siberia in the north to Australia in the south, and as far as Pakistan to the west and Saipan to the east. Transmission of JEV in temperate zones is epidemic with the majority of cases occurring in summer months, while transmission in tropical zones is endemic and occurs year-round at lower rates. To test the hypothesis that viruses circulating in these two geographical zones are genetically distinct, we applied Bayesian phylogeographic, categorical data analysis and phylogeny-trait association test techniques to the largest JEV dataset compiled to date, representing the envelope (E) gene of 487 isolates collected from 12 countries over 75 years. We demonstrated that GIII and the recently emerged GI-b are temperate genotypes likely maintained year-round in northern latitudes, while GI-a and GII are tropical genotypes likely maintained primarily through mosquito-avian and mosquito-swine transmission cycles. This study represents a new paradigm directly linking viral molecular evolution and climate
Probing RS scenarios of flavour at LHC via leptonic channels
We study a purely leptonic signature of the Randall-Sundrum scenario with
Standard Model fields in the bulk at LHC: the contribution from the exchange of
Kaluza-Klein (KK) excitations of gauge bosons to the clear Drell-Yan reaction.
We show that this contribution is detectable (even with the low luminosities of
the LHC initial regime) for KK masses around the TeV scale and for sufficiently
large lepton couplings to KK gauge bosons. Such large couplings can be
compatible with ElectroWeak precision data on the Zff coupling in the framework
of the custodial O(3) symmetry recently proposed, for specific configurations
of lepton localizations (along the extra dimension). These configurations can
simultaneously reproduce the correct lepton masses, while generating acceptably
small Flavour Changing Neutral Current (FCNC) effects. This LHC
phenomenological analysis is realistic in the sense that it is based on fermion
localizations which reproduce all the quark/lepton masses plus mixing angles
and respect FCNC constraints in both the hadron and lepton sectors.Comment: 15 pages, 6 Figures, Latex fil
Kaon pair production in proton-nucleus collisions at 2.83 GeV kinetic energy
The production of non-phi K+K- pairs by protons of 2.83 GeV kinetic energy on
C, Cu, Ag, and Au targets has been investigated using the COSY-ANKE magnetic
spectrometer. The K- momentum dependence of the differential cross section has
been measured at small angles over the 0.2--0.9 GeV/c range. The comparison of
the data with detailed model calculations indicates an attractive K- -nucleus
potential of about -60 MeV at normal nuclear matter density at a mean momentum
of 0.5 GeV/c. However, this approach has difficulty in reproducing the
smallness of the observed cross sections at low K- momenta.Comment: 7 pages, 5 figures, 1 tabl
Minimal Universal Extra Dimensions in CalcHEP/CompHEP
We present an implementation of the model of minimal universal extra
dimensions (MUED) in CalcHEP/CompHEP. We include all level-1 and level-2
Kaluza-Klein (KK) particles outside the Higgs sector. The mass spectrum is
automatically calculated at one loop in terms of the two input parameters in
MUED: the radius of the extra dimension and the cut-off scale of the model. We
implement both the KK number conserving and the KK number violating
interactions of the KK particles. We also account for the proper running of the
gauge coupling constants above the electroweak scale. The implementation has
been extensively cross-checked against known analytical results in the
literature and numerical results from other programs. Our files are publicly
available and can be used to perform various automated calculations within the
MUED model.Comment: 32 pages, 4 figures, 6 tables, invited contribution for New Journal
of Physics Focus Issue on 'Extra Space Dimensions', the model file can be
downloaded from http://home.fnal.gov/~kckong/mued
Cosmic ray tests of the D0 preshower detector
The D0 preshower detector consists of scintillator strips with embedded
wavelength-shifting fibers, and a readout using Visible Light Photon Counters.
The response to minimum ionizing particles has been tested with cosmic ray
muons. We report results on the gain calibration and light-yield distributions.
The spatial resolution is investigated taking into account the light sharing
between strips, the effects of multiple scattering and various systematic
uncertainties. The detection efficiency and noise contamination are also
investigated.Comment: 27 pages, 24 figures, submitted to NIM
Tevatron-for-LHC Report: Preparations for Discoveries
This is the "TeV4LHC" report of the "Physics Landscapes" Working Group,
focused on facilitating the start-up of physics explorations at the LHC by
using the experience gained at the Tevatron. We present experimental and
theoretical results that can be employed to probe various scenarios for physics
beyond the Standard Model.Comment: 222 pp., additional contribution added, typos/layout correcte
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