Wavelength-selected Neutron Pulses Formed by a Spatial Magnetic Neutron Spin Resonator

AbstractWe present a novel type of spatial magnetic neutron spin resonator whose time and wavelength resolution can be de- coupled from each other by means of a travelling wave mode of operation. Combined with a pair of highly efficient polarisers such a device could act simultaneously as monochromator and chopper, able to produce short neutron pulses, whose wavelength, spectral width and duration could be varied almost instantaneously by purely electronic means with- out any mechanical modification of the experimental setup. To demonstrate the practical feasibility of this technique we have designed and built a first prototype resonator consisting of ten individually switchable modules which allows to produce neutron pulses in the microsecond regime. It was installed at a polarised 2.6Å neutron beamline at the 250kW TRIGA research reactor of the Vienna University of Technology where it could deliver pulses of 55μs duration, which is about three times less than the passage time of the neutrons through the resonator itself. In order to further improve the achievable wavelength resolution to about 3% a second prototype resonator, consisting of 48 individual modules with optimised field homogeneity and enlarged beam cross-section of 6 × 6cm2 was developed. We present the results of first measurements which demonstrate the successful operation of this device

Biomechanics and hydrodynamics of prey capture in the Chinese giant salamander reveal a high-performance jaw-powered suction feeding mechanism

During the evolutionary transition from fish to tetrapods, a shift from uni- to bidirectional suction feeding systems followed a reduction in the gill apparatus. Such a shift can still be observed during metamorphosis of salamanders, although many adult salamanders retain their aquatic lifestyle and feed by high-performance suction.Unfortunately, little is known about the interplay between jaws and hyobranchial motions to generate bidirectional suction flows. Here,we study the cranial morphology, aswell as kinematic and hydrodynamic aspects related to prey capture in the Chinese giant salamander (Andrias davidianus). Compared with fish and previously studied amphibians, A. davidianus uses an alternative suction mechanismthat mainly relies on accelerating water by separating the ‘plates’ formed by the long and broad upper and lower jaw surfaces. Computational fluid dynamics simulations, based on three-dimensional morphology and kinematical data from high-speed videos, indicate that the viscerocranial elements mainly serve to accommodate the water that was given a sufficient anterior-to-posterior impulse beforehand by powerful jawseparation.We hypothesize that this modifiedway of generating suction is primitive for salamanders, and that this behaviour could have played an important role in the evolution of terrestrial life in vertebrates by releasing mechanical constraints on the hyobranchial system

Circulating B-vitamin biomarkers and B-vitamin supplement use in relation to quality of life in patients with colorectal cancer: results from the FOCUS consortium

Background: B vitamins have been associated with the risk and progression of colorectal cancer (CRC), given their central roles in nucleotide synthesis and methylation, yet their association with quality of life in established CRC is unclear.Objectives: To investigate whether quality of life 6 months postdiagnosis is associated with: 1) circulating concentrations of B vitamins and related biomarkers 6 months postdiagnosis; 2) changes in these concentrations between diagnosis and 6 months postdiagnosis; 3) B-vitamin supplement use 6 months postdiagnosis; and 4) changes in B-vitamin supplement use between diagnosis and 6 months postdiagnosis.Methods: We included 1676 newly diagnosed stage I-III CRC patients from 3 prospective European cohorts. Circulating concentrations of 9 biomarkers related to the B vitamins folate, riboflavin, vitamin B6, and cobalamin were measured at diagnosis and 6 months postdiagnosis. Information on dietary supplement use was collected at both time points. Health-related quality of life (global quality of life, functioning scales, and fatigue) was assessed by the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire 6 months postdiagnosis. Confounder-adjusted linear regression analyses were performed, adjusted for multiple testing.Results: Higher pyridoxal 5'-phosphate (PLP) was cross-sectionally associated with better physical, role, and social functioning, as well as reduced fatigue, 6 months postdiagnosis. Associations were observed for a doubling in the hydroxykynurenine ratio [3-hydroxykynurenine: (kynurenic acid + xanthurenic acid + 3-hydroxyanthranilic acid + anthranilic acid); an inverse marker of vitamin B6] and both reduced global quality of life (beta = -3.62; 95% CI: -5.88, -1.36) and worse physical functioning (beta = -5.01; 95% CI: -7.09, -2.94). Dose-response relations were observed for PLP and quality of life. No associations were observed for changes in biomarker concentrations between diagnosis and 6 months. Participants who stopped using B-vitamin supplements after diagnosis reported higher fatigue than nonusers.Conclusions: Higher vitamin B6 status was associated with better quality of life, yet limited associations were observed for the use of B-vitamin supplements. Vitamin B6 needs further study to clarify its role in relation to quality of life

-laser polishing of polytetrafluoroethylene surfaces

The surface roughness and the optical properties of dense polytetrafluoroethylene (PTFE) can be modified by 157\un{nm} \chem{F_2}-laser irradiation in \chem{N_2} atmosphere. With PTFE foils, laser-treatment results in an improved transparency which is attributed to a smoothening of the surface. The treated foils exhibit a similar mechanical stability as the untreated ones

Alveoläre Echinokokkose bei einem Hund in Österreich

Die alveoläre Echinokokkose (AE) ist eine zoonotische Infektionskrankheit, die durch das invasiv wachsende Larvenstadium des Fuchsbandwurms Echinococcus multilocularis (Echinococcus alveolaris) zu zystischen Veränderungen in parenchymatösen Organen, meist der Leber, führt. Kanine AE ist die Folge einer Aufnahme infektiöser Eier aus dem Kot von Endwirten, vor allem Kaniden. In diesen Fällen sind Hunde nicht, wie biologisch vorgesehen, die Endwirte für den Parasiten, sondern Fehlzwischenwirte. Dieser Fall beschreibt einen dreijährigen, kastrierten Mischlingsrüden, der mit einer großen abdominalen Umfangsvermehrung an die Veterinärmedizinische Universität Wien überwiesen wurde. Mittels Röntgenuntersuchung, Ultraschalluntersuchung und Computertomographie konnte eine 14 x 13 cm große, flüssigkeitsgefüllte, dickwandige, nicht-septierte Umfangsvermehrung zwischen Leber und Magen diagnostiziert werden, deren Ursprung der Leber zugeschrieben wurde. Die Masse wurde mitsamt den betroffenen Leberlappen reseziert. In pathohistologischen und parasitologischen Untersuchungen des Resektats wurden Metazestoden von E. multilocularis nachgewiesen. Der Befund wurde mittels molekularen (PCR/Sequenzierung) und serologischen (ELISA und Westernblot) Verfahren bestätigt. Die Prognose wurde aufgrund der Veränderungen an Leber und Bauchfell als vorsichtig eingestuft. Eine Therapie mit Albendazol (10 mg/kg einmal täglich peroral) wurde eingeleitet, um der Ausbildung weiterer Echinokokkenzysten vorzubeugen. Eine Ultraschall-Kontrolluntersuchung des Abdomens sieben Monate nach dem chirurgischen Eingriff zeigte keine abweichenden Befunde. Serologische Untersuchungen sieben und neuneinhalb Monate nach der Operation ergaben negative Ergebnisse. Da die Inzidenz der AE beim Menschen in Österreich seit 2001 steigend ist, muss auch mit einer steigenden Infektionsrate bei anderen Zwischenwirten einschließlich Hunden gerechnet werden. Folglich muss die kanine AE als Differentialdiagnose für zystische raumfordernde Prozesse im Abdomen in Betracht gezogen werden