Pulsed, lock-in and frequency modulated thermography are three alternative nondestructive evaluation techniques. The defect imaging performance of these techniques are compared using: matched excitation energy; the same carbon fiber composite test piece and infrared camera system. The lock-in technique suffer from "blind frequencies" at which phase images for some defects disappear. It is shown that this problem can be overcome by using frequency modulated (chirp) excitation and an image fusion algorithm is presented that enhance phase imaging of defects. The signal-to-noise ratios (SNR) of defect images obtained by the three techniques are presented. For the shallowest defects (depths 0.25 and 0.5 mm, 6 mm diameter), the pulsed technique exhibits the highest SNRs. For deeper defects the SNRs of the three techniques are similar in magnitude under matched excitation energy condition.
The introduction of light sheet fluorescence microscopy (LSFM) has overcome the challenges in conventional optical microscopy. Among the recent breakthroughs in fluorescence microscopy, LSFM had been proven to provide a high three-dimensional spatial resolution, high signal-to-noise ratio, fast imaging acquisition rate, and minuscule levels of phototoxic and photodamage effects. The aforementioned auspicious properties are crucial in the biomedical and clinical research fields, covering a broad range of applications: from the super-resolution imaging of intracellular dynamics in a single cell to the high spatiotemporal resolution imaging of developmental dynamics in an entirely large organism. In this review, we provided a systematic outline of the historical development of LSFM, detailed discussion on the variants and improvements of LSFM, and delineation on the most recent technological advancements of LSFM and its potential applications in single molecule/particle detection, single-molecule super-resolution imaging, imaging intracellular dynamics of a single cell, multicellular imaging: cell-cell and cell-matrix interactions, plant developmental biology, and brain imaging and developmental biology.
High power light emitting diode (LED) arrays have been investigated as excitation sources for long pulse and lock-in thermography. Images of artificial defects in a carbon fibre reinforced plastic (CFRP) composite sample are compared, by image contrast signal-to-noise ratio estimates, with those obtained using conventional incandescent flash and lock-in excitation sources. The LED arrays had to be mounted on heat sinks with active cooling in to prevent them exceeding their thermal tolerance. Despite this cooling the LED arrays were still found to emit some IR radiation, although far less than conventional incandescent light sources.
BackgroundRifampicin or rifampin (R) is a common drug used to treat inactive meningitis, cholestatic pruritus and tuberculosis (TB), and it is generally prescribed for long-term administration under regulated dosages. Constant monitoring of rifampicin is important for controlling the side effects and preventing overdose caused by chronic medication. In this study, we present an easy to use, effective and less costly method for detecting residual rifampicin in urine samples using protein (bovine serum albumin, BSA)-stabilized gold nanoclusters (BSA-Au NCs) adsorbed on a paper substrate in which the concentration of rifampicin in urine can be detected via fluorescence quenching. The intensity of the colorimetric assay performed on the paper-based platforms can be easily captured using a digital camera and subsequently analyzed.ResultsThe decreased fluorescence intensity of BSA-Au NCs in the presence of rifampicin allows for the sensitive detection of rifampicin in a range from 0.5 to 823 µg/mL. The detection limit for rifampicin was measured as 70 ng/mL. The BSA-Au NCs were immobilized on a wax-printed paper-based platform and used to conduct real-time monitoring of rifampicin in urine.ConclusionWe have developed a robust, cost-effective, and portable point-of-care medical diagnostic platform for the detection of rifampicin in urine based on the ability of rifampicin to quench the fluorescence of immobilized BSA-Au NCs on wax-printed papers. The paper-based assay can be further used for the detection of other specific analytes via surface modification of the BSA in BSA-Au NCs and offers a useful tool for monitoring other diseases.Electronic supplementary materialThe online version of this article (doi:10.1186/s12951-015-0105-5) contains supplementary material, which is available to authorized users.
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