Multimodal wide-field two-photon excitation imaging: characterization of the technique for in vivo applications

We report fast, non-scanning, wide-field two-photon fluorescence excitation with spectral and lifetime detection for in vivo biomedical applications. We determined the optical characteristics of the technique, developed a Gaussian flat-field correction method to reduce artifacts resulting from non-uniform excitation such that contrast is enhanced, and showed that it can be used for ex vivo and in vivo cellular-level imaging. Two applications were demonstrated: (i) ex vivo measurements of beta-amyloid plaques in retinas of transgenic mice, and (ii) in vivo imaging of sulfonated gallium(III) corroles injected into tumors. We demonstrate that wide-field two photon fluorescence excitation with flat-field correction provides more penetration depth as well as better contrast and axial resolution than the corresponding one-photon wide field excitation for the same dye. Importantly, when this technique is used together with spectral and fluorescence lifetime detection modules, it offers improved discrimination between fluorescence from molecules of interest and autofluorescence, with higher sensitivity and specificity for in vivo applications

High-Resolution High-Power Quasi-Optical Free-Space Spectrometer for Dielectric and Magnetic Measurements in Millimeter Waves

Abstract-This paper presents a high-resolution high-power free-space dielectric and magnetic measurement technique for evaluating the complex dielectric permittivity and complex magnetic permeability of solid materials in millimeter waves at room temperature. This method enables us to obtain broad-band highresolution transmittance spectra using a quasi-optical free-space spectrometer equipped with an extended V-band (40-90 GHz) backward-wave oscillator as a high-power tunable source of coherent radiation. Due to the sufficiently strong energy throughput in the transmission and a very fine frequency sweep step of the measurement, this instrumentation is superior in obtaining reliable complex permittivity and complex permeability of absorbing dielectrics and ferrites with great stability and reproducibility over a much broader millimeter-wave frequency range. Simultaneous determination of dielectric permittivity and magnetic permeability can be achieved from a single set of measurements. Measurement results are reported for a variety of dielectrics and ferrites and compared with previously published data

Commissioning of the ArDM experiment at the Canfranc underground laboratory: First steps towards a tonne-scale liquid argon time projection chamber for Dark Matter searches

The Argon Dark Matter (ArDM) experiment consists of a liquid argon (LAr) time projection chamber (TPC) sensitive to nuclear recoils, resulting from scattering of hypothetical Weakly Interacting Massive Particles (WIMPs) on argon targets. With an active target mass of 850 kg ArDM represents an important milestone towards developments for large LAr Dark Matter detectors. Here we present the experimental apparatus currently installed underground at the Laboratorio Subterráneo de Canfranc (LSC), Spain. We show data on gaseous or liquid argon targets recorded in 2015 during the commissioning of ArDM in single phase at zero E-field (ArDM Run I). The data confirms the overall good and stable performance of the ArDM tonne-scale LAr detector.ISSN:1475-751

Tools of the Trade: Investigations into Design Strategies of Small Molecules to Target Components in Alzheimer's Disease

The growing prevalence of Alzheimer's disease (AD) has warranted the development of effective therapeutic methods. Current available drugs for AD (i.e., acetylcholinesterase (AChE) inhibitors and N-methyl-D-aspartate (NMDA) receptor antagonists) have only offered brief symptomatic relief. Considering that the numbers affected by AD are projected to substantially rise, long-term strategies are urgently needed. The multiple series of small molecules to combat AD have been expanded, with current methods taking aim at factors, such as misfolded protein accumulation, metal ion dyshomeostasis, and oxidative stress. This concept article focuses on describing the design of compounds to target various components of AD and underlining recent advances that have been made.close0