No abstract

We measure the diffuse reflection spectrum of solid samples such as explosives (TNT, RDX, PETN), fertilizers (ammonium nitrate, urea), and paints (automotive and military grade) at a stand-off distance of 5 m using a mid-infrared supercontinuum light source with 3.9 W average output power. The output spectrum extends from 750-4300 nm, and it is generated by nonlinear spectral broadening in a 9 m long fluoride fiber pumped by high peak power pulses from a dual-stage erbium-ytterbium fiber amplifier operating at 1543 nm. The samples are distinguished using unique spectral signatures that are attributed to the molecular vibrations of the constituents. Signal-to-noise ratio (SNR) calculations demonstrate the feasibility of increasing the stand-off distance from 5 to ~150 m, with a corresponding drop in SNR from 28 to 10 dB.

We demonstrate an all-fiber supercontinuum source that generates a continuous spectrum from 1.6 μm to >11  μm with 417 mW on-time average power at 33% duty cycle. By utilizing a master oscillator power amplifier pump with three amplification stages and concatenating solid core ZBLAN, arsenic sulfide, and arsenic selenide fibers, we shift 1550 nm light to ∼4.5  μm, ∼6.5  μm, and >11  μm, respectively. With 69 mW past 7.5 μm, this source provides both high power and broad spectral expansion, while outputting a single fundamental mode.

It is argued that it is feasible to screen for intellectual disabilities in prisons and, given the inequalities to which prisoners with intellectual disabilities are subject in prison, it is time for such screening to be rolled out to all prisons.

Background: Ablative fractional laser (AFXL) is an acknowledged technique to increase uptake of topical agents in skin. Micro thermal ablation zones (MAZs) consist of ablated vertical channels surrounded by a coagulation zone (CZ). Laser scanning confocal microscopy (LSCM) images individual MAZs at 733 nm (reflectance confocal microscopy (RCM)). Further, LSCM can image sodium fluorescein (NaF) fluorescence with 488 nm excitation (fluorescence confocal microcopy (FCM)), a small hydrophilic test molecule (370 MW, log P -1.52), which may simulate uptake, bio-distribution, and kinetics of small hydrophilic drugs.Objectives: To explore LSCM for combined investigations of CZ thickness and uptake, bio-distribution, and kinetics of NaF in AFXL-exposed skin.Study Designs/Methods and materials: Excised human abdominal skin samples were exposed to AFXL (15 mJ/microbeam, 2% density) and NaF gel (1000 mg/ml, 10 ml/cm2) in six repetitions, including untreated control samples. CZ thickness and spatiotemporal fluorescence intensities (FI) were quantified up to four hours after NaF application by RCM and FCM. Test sites were scanned to a depth of 200 mm, quantifying thickness of skin compartments (stratum corneum, epidermis, upper dermis), individual CZ thicknesses and FI in CZ and surrounding skin.Results: RCM images established skin morphology to a depth of 200 mm. The CZ thickness measurements were feasible to a depth of 50 mm, and remained unchanged over time at 50 mm (P > 0.5). FI were detected to a depth of 160 mm and remained constant in CZ up to four hours after NaF application (15 minutes: 79 AU (73-92 AU), 60 minutes: 72 AU (58-82 AU), four hours: 78 AU (71-90 AU), P > 0.1). In surrounding skin, FI increased significantly over time, but remained lower than FI in CZ (15 minutes: 21 AU (17-22 AU), 60 minutes: 21 AU (19-26 AU), four hours: 42 (31-48 AU), P ¼ 0.03). AFXL-processed skin generated higher FI compared to non-laser processed skin in epidermis and upper dermis at 60 minutes and four hours (P ¼ 0.03). Conclusions: By LSCM, assessment of the AFXL-induced CZ thickness was feasible to a depth of 50 mm, and assessment of FI from a small hydrophilic test molecule, NaF in CZ and surrounding skin feasible to a depth of 160 mm.