Calibration of spectral imaging instruments is a prerequisite for many applications, in particular in the field of Earth observation. In this contribution we will present a novel traceability route to celebrate spectral imaging instruments, based on tunable radiance source that is referenced to a primary detector standard.
DOCUMENT
We have developed an SI-traceable narrow-band tunable radiance source based on an optical parametric oscillator (OPO) and an integrating sphere for the calibration of spectroradiometers. The source is calibrated with a reference detector over the ultraviolet/visible spectral range with an uncertainty of <1%. As a case study, a CubeSat spectroradiometer has been calibrated for radiance over its operating range from 370 nm to 480 nm. To validate the results, the instrument has also been calibrated with a traditional setup based on a diffuser and an FEL lamp. Both routes show good agreement within the combined measurement uncertainty. The OPO-based approach could be an interesting alternative to the traditional method, not only because of reduced measurement uncertainty, but also because it directly allows for wavelength calibration and characterization of the instrumental spectral response function and stray light effects, which could reduce calibration time and cost.
DOCUMENT
Knowledge of the time of deposition is pivotal in forensic investigations. Recent studies show that changes in intrinsic fluorescence over time can be used to estimate the age of body fluids. These changes have been attributed to oxidative modifications caused by protein–lipid interactions. This pilot study aims to explore the impact of these modifications on body fluid fluorescence, enhancing the protein–lipid model system for age estimation. Lipid and protein oxidation markers, including protein carbonyls, dityrosine, advanced glycation end-products (AGEs), malondialdehyde (MDA), and 4-hydroxynonenal (HNE), were studied in aging semen, urine, and saliva over 21 days. Surface plasmon resonance imaging (SPRi), enzyme-linked immunosorbent assay (ELISA), and fluorescence spectroscopy were applied. Successful detection of AGE, dityrosine, MDA, and HNE occurred in semen and saliva via SPRi, while only dityrosine was detected in urine. Protein carbonyls were measured in all body fluids, but only in saliva was a significant increase observed over time. Additionally, protein fluorescence loss and fluorescent oxidation product formation were assessed, showing significant decreases in semen and saliva, but not in urine. Although optimization is needed for accurate quantification, this study reveals detectable markers for protein and lipid oxidation in aging body fluids, warranting further investigation.
MULTIFILE
Fluorescence microscopy is an indispensable technique to resolve structure and specificity in many scientific areas such as diagnostics, health care, materials- and life sciences. With the development of multi-functional instruments now costing hundreds of thousands of Euros, the availability and access to high-tech instrumentation is increasingly limited to larger imaging facilities. Here, we will develop a cost-effective alternative by combining a commercially available solution for high-resolution confocal imaging (the RCM from confocal.nl) with an open-hardware microscopy framework, the miCube, developed in the Laboratory of Biophysics of Wageningen University & Research. In addition, by implementing a recent invention of the applicant for the spectral separation of different emitters, we will improve the multiplexing capabilities of fluorescence microscopy in general and the RCM in particular. Together, our new platform will help to translate expertise and know-how created in an academic environment into a commercially sustainable future supporting the Dutch technology landscape.