Continuous arterial spin labeling (CASL) in the monkey brain at high magnetic field using a three-coil approach

CASL experiments in the monkey brain were performed at 4.7 T and 7 T using a separate labeling coil. Increased sensitivity and SNR were achieved by a custom-made three-coil setup and high magnetic field with its increased T1. We report the development and optimization of the setup and first experiments in the monkey (macaca mulatta). Parameters for continuous labeling (label power, label duration, post label delay) were optimized to measure gray matter rCBF and fCBF changes, reporting excellent multi-slice coverage at high resolution of 0.75 – 1 mm in-plane

Perfusion-based functional imaging in the monkey brain at 7T: investigations of CASL parameters

Perfusion-based imaging in the monkey primary visual cortex was performed at 7 T applying continuous arterial spin labeling (CASL). Increased perfusion sensitivity and SNR at high magnetic field (due to larger T1) was further optimized using a custom-made three-coil setup with a separate neck labeling coil. We investigated the labeling parameters to obtain relative fCBF changes in the anaesthetized monkey. We report excellent functional activation of striate cortex at high resolution of 0.75x0.9mm2 in-plane. Interestingly, the optimal parameter set for obtaining highest signal changes of rCBF are different from the reported values for imaging gray matter CBF

Application of non-invasive central aortic pressure assessment in clinical trials: Clinical experience and value

Pressure measured with a cuff and sphygmomanometer in the brachial artery is accepted as an important predictor of future cardiovascular (CV) events. However, recent clinical evidence suggests that central aortic pressure (CAP) provides additional information for assessing CV risk than brachial blood pressure (BrBP). Central hemodynamics can now be non-invasively assessed with a number of devices, however, the methodology employed to measure CAP, in order to better identify the patients at higher CV risk in clinical practice, is still controversial. The purpose of this article is to review the technology behind the non-invasive measurement of CAP via the effects of different classes of antihypertensive drugs on CAP and the data supporting the predictive value of assessing CAP on clinical outcomes, and to foster the transfer of methodological knowledge from clinical trials into routine clinical practice

Rationale and study design of the Prospective comparison of Angiotensin Receptor neprilysin inhibitor with Angiotensin receptor blocker MEasuring arterial sTiffness in the eldERly (PARAMETER) study.

Hypertension in elderly people is characterised by elevated systolic blood pressure (SBP) and increased pulse pressure (PP), which indicate large artery ageing and stiffness. LCZ696, a first-in-class angiotensin receptor neprilysin inhibitor (ARNI), is being developed to treat hypertension and heart failure. The Prospective comparison of Angiotensin Receptor neprilysin inhibitor with Angiotensin receptor blocker MEasuring arterial sTiffness in the eldERly (PARAMETER) study will assess the efficacy of LCZ696 versus olmesartan on aortic stiffness and central aortic haemodynamics

Advanced code-division multiplexers for superconducting detector arrays

Multiplexers based on the modulation of superconducting quantum interference devices are now regularly used in multi-kilopixel arrays of superconducting detectors for astrophysics, cosmology, and materials analysis. Over the next decade, much larger arrays will be needed. These larger arrays require new modulation techniques and compact multiplexer elements that fit within each pixel. We present a new in-focal-plane code-division multiplexer that provides multiplexing elements with the required scalability. This code-division multiplexer uses compact lithographic modulation elements that simultaneously multiplex both signal outputs and superconducting transition-edge sensor (TES) detector bias voltages. It eliminates the shunt resistor used to voltage bias TES detectors, greatly reduces power dissipation, allows different dc bias voltages for each TES, and makes all elements sufficiently compact to fit inside the detector pixel area. These in-focal-plane code-division multiplexers can be combined with multi-gigahertz readout based on superconducting microresonators to scale to even larger arrays.Comment: 8 pages, 3 figures, presented at the 14th International Workshop on Low Temperature Detectors, Heidelberg University, August 1-5, 2011, proceedings to be published in the Journal of Low Temperature Physic

Resonant Steps in the Characteristics of a Josephson Junction Coupled to a Transmission Line

A novel circuit is described which functions as an electronic analog of lumped element transmission line. The circuit requires only operational amplifiers, resistors, and capacitors. This module was coupled to a Josephsonj unction simulator and current voltage characteristics of the combined system were recorded. Steps were observed at voltages determined by the appropriate line resonances. When the transmission line was terminated with loads less than the characteristic impedance, chaos was seen in the lower steps. Similar results were obtained by numerical integration of the corresponding system of differential equations

Optical detection of a single rare-earth ion in a crystal

Rare-earth-doped laser materials show strong prospects for quantum information storage and processing, as well as for biological imaging, due to their high-Q 4f↔4f optical transitions. However, the inability to optically detect single rare-earth dopants has prevented these materials from reaching their full potential. Here we detect a single photostable Pr(3+) ion in yttrium aluminium garnet nanocrystals with high contrast photon antibunching by using optical upconversion of the excited state population of the 4f↔4f optical transition into ultraviolet fluorescence. We also demonstrate on-demand creation of Pr(3+) ions in a bulk yttrium aluminium garnet crystal by patterned ion implantation. Finally, we show generation of local nanophotonic structures and cell death due to photochemical effects caused by upconverted ultraviolet fluorescence of praseodymium-doped yttrium aluminium garnet in the surrounding environment. Our study demonstrates versatile use of rare-earth atomic-size ultraviolet emitters for nanoengineering and biotechnological applications