Correlated electromigration of H in the switchable mirror YH3-delta

The optical method of Den Broeder et al. was extended to study migration of hydrogen vacancies in Y

Growth trajectories of the human fetal brain in healthy and complicated pregnancies and associations with neurodevelopmental outcome in the early life course

Background There is a need for non-invasive prenatal markers of the brain to assess fetuses at risk for poor postnatal neurodevelopmental outcome. Periconceptional maternal conditions and pregnancy complications impact prenatal brain development. Aims To investigate associations between growth trajectories of fetal brain structures and neurodevelopmental outcome in children in the early life course. Study design Periconceptional prospective observational cohort. Subjects Singleton pregnancies were included in the Rotterdam periconception cohort. Two- and three-dimensional ultrasound scans at 22, 26 and 32 weeks gestational age were analysed. Outcome measures Head circumference (HC), cerebellum, corpus callosum (CC), Sylvian fissure, insula and parieto-occipital fissure (POF) were measured. Neurodevelopment was evaluated using the Age-and-Stages-questionnaire-3 (ASQ-3) and the Child-Behaviour-Checklist (CBCL) at 2 years of age. Linear mixed models, used to estimate the prenatal brain growth trajectories, and linear regression models, used to evaluate the associations between prenatal brain structures and neurodevelopmental outcomes, were applied in the total study population, and in subgroups: fetal growth restriction (FGR), preterm birth (PTB), fetal congenital heart

Evaluation of asymmetric orthogonal cyanine fluorophores

Pentamethine cyanine (Cy5) fluomphores have proven to be versatile imaging agents (i.e., tracers) for a range of micro- and macroscopic imaging applications, including image-guided surgery. In this study the relationship between the structure of asymmetric Cy5 fluorophores and their photophysical properties was studied. To this end, seven Cy5 analogues, bearing orthogonal N-indole substituents (H, SC3-, or benzene), were synthesised and evaluated. In-depth analysis revealed that introduction of sulfonates enhanced the fluorescence brightness and photostability, while reducing the lipophilicity, serum binding and stacking tendency. The addition of benzene moieties induced a bathochromic shift of 10-20 nm, increased the lipophilicity (LogP = -1.56-1.23) and serum binding (67.3-93.8% bound), as well as negatively impacted the brightness (0.74-42.9 . 10(3) M-1 cm(-1)), photostability (24.4-90.6% remaining), and stacking tendency. Chemical stability was uninfluenced by the substitution pattern. Additionally, the generation of a c[RGDyK]-based hybrid tracer based on one of these fluomphores in combination with a diethylenetriaminepentaacetic acid (DTPA) chelate and an In-111-isotope was reported. This compound was evaluated in vitro using alpha(v)beta(3)-overexpressing Ge beta 3 cells and in vivo using a 4T1 mouse tumour model. Overall, the presented results imply that alterations of the asymmetrical orthogonal Cy5 fluomphore structure have impact on the (photo)physical properties. Furthermore, the orthogonal Cy5 fluorophore framework can readily be applied in tracer development.Radiolog

Structural similarity between the magnetic-flux profile in superconductors and the surface of a 2d rice pile

We analyze the magnetic-flux profile in the critical state of an YB

Noise correction for roughening analysis of magnetic flux profiles in YBa2Cu3O7-x

The presence of experimental noise may greatly reduce the accuracy of experimentally determined growth and roughness exponents, which characterize a growing self-amne interface. A separate determination of the experimental noise enables a straightforward correction, which we demonstrate on experiments on the roughening of magnetic flux profiles in the critical state of YB

Surface roughening and self-organized criticality: The influence of quenched disorder

Self-organized criticality (SOC) has attracted considerable interest due to its possible wide ranging implications on a broad range of subjects. However, the experimental observation of SOC using stringent criteria has been difficult and the question of the critical parameters to observe SOC remains open. This is partly due to the fact that there are different criteria applied in order to claim SOC. Here we endeavour to study two aspects of this. First of all, we study the influence of the presence of quenched disorder on the appearance of SOC in the vortex dynamics in niobium by changing the amount of hydrogen impurities. Furthermore, we study whether the roughness properties of the pile surface can be used as a criterion for the appearance of SOC on a par with the observation of finite-size scaling. For this purpose, we compare the roughness and dynamic exponents of the vortex landscape to the avalanche size distribution for different amounts of disorder. The absence of a transition to SOC in the roughness exponent implies that the presence of a rough surface by itself cannot be used as a sufficient criterion for the observation of SOC. A determination of the dynamics of the surface properties, however, shows a transition similar to that of the avalanche properties. © EDP Sciences

Huge compact flux avalanches in superconducting Nb thin films

Using a magneto-optical technique we perform a quantitative analysis of magnetic flux penetration in superconducting niobium thin films on A-plane (112̄0) sapphire substrates as a function of temperature (1.5 K ≤ T ≤

Field line distribution in a mixed sensor

We have demonstrated that a very low magnetic field can be detected by a sensor combining a superconducting pick-up loop and a GMR element [1], [2]. In this device, the excitation field applied to the superconductor generates a supercurrent running through the loop. This current is driven through a constriction, where it generates high density magnetic field lines that can be detected by the GMR sensor. We have performed magneto-optical imaging on a YBCO ring with a constriction to estimate the magnetic field—enhancement and the localization of the field lines in this design for applied fields down to 1 μT. The obtained measurements give the vertical component of the local magnetic field. Locally the field lines are enhanced by a factor larger than 200 for fields small enough to induce a current lower than the critical current. A decrease of the gain for higher applied fields is observed, when the critical current is reached. We present also a calculation of the gain, taking into account the precise distribution of current in the rectangular section of the superconductor [3] and the inductance of the loop. These results are in agreement with finite element modeling. The gain for various dimensions and aspect ratio's is given and compared to the experimental results. An optimized design is given for magnetoencephalography applications, in order to replace low-Tc SQUIDs used in the present apparatus. The expected sensitivity of this system is calculated to be in the range of a few fT/ Hz