Application of Optical Coherence Tomography (OCT) to Evaluate the Adverse Effects of 2,4-D Dimethylammonium on Morphological Changes in Riceland Prawn (Macrobrachium lanchesteri).

2,4-D dimethylammonium, a widely used herbicide, accumulates in aquatic animals, posing risks to both their populations and human consumers. This study evaluated the effects of 2,4-D on Riceland prawn (Macrobrachium lanchesteri) using Optical Coherence Tomography (OCT) to assess morphological changes. The activity of acetylcholinesterase (AChE), catalase (CAT), and glutathione S-transferase (GST) was also measured.

Optical fiber-coupled Kretschmann SPR sensor with re-attachable gold nano-thin film sensing chip.

We designed and demonstrated a portable and reusable surface plasmon resonance (SPR) sensor based on an optical fiber-coupled Kretschmann configuration with a variable detection limit enabled by the re-attachable gold nano-thin film. The prism angle of SPR has been optimized to 63.5 degrees to enable the SPR sensor to operate in the near-infrared band.

Assessment of the effects of 2,4-D-dichlorophenoxyacetic acid-based herbicide exposure in eggs and embryos of golden apple snails using OCT.

This study aimed to evaluate the effects of herbicide 2, 4-D-dichlorophenoxy acetic acid on golden apple snail eggs and embryos. Additionally, the study assessed the applicability of optical coherence tomography (OCT), a non-invasive depth cross-sectional microscopic imaging technique, as a novel method, to the best of our knowledge, for studying morphological changes in golden apple snail eggs and embryos, in comparison to the conventional approach of using white light microscopy. The study revealed that the herbicide 2,4-D-dichlorophenoxy acetic acid affected the hatchery rate and morphological changes of the eggs and embryos.

Adverse effects of 2,4-D dimethylammonium based-herbicide on Acetylcholinesterase expression in Nile tilapia (Oreochromis niloticus).

In this study, the evaluation of a 2,4-D dimethylammonium based-herbicide impacted on Nile tilapia was done. The effects focus on Acetylcholinesterase (AChE) expression in the brain, gill, muscle, and plasma using antibody techniques. Our findings revealed a decrease in AChE expression with prolonged exposure.

Hybrid Cyanine/Methotrexate Nanoparticles for Synergistic PDT/Chemotherapy of Breast Cancer.

Typically, nanomedicine was prepared using a nanocarrier to load cargo for specific purposes. In this work, a carrier-free nanosystem for imaging and photodynamic (PDT)/chemo combination therapy was developed using simple self-assembly of a dye and a chemotherapeutic agent. The resulting nanoparticles () exhibited a spherical morphology with a size of 240.

PEGylated Aza-BODIPY Nanoparticles for Photothermal Therapy.

Photothermal therapy is a promising treatment modality in the realm of cancer therapy. Photothermal nanomaterials that absorb and emit in the near-infrared range (750-900 nm) have drawn a lot of attention recently because of the deep penetration of NIR light in biological tissue. Most nanomaterials, however, are produced by encapsulating or altering the surface of a nanoplatform, which has limited loading capacity and long-term storage.

Optical coherence tomography as an alternative tool for evaluating the effects of glyphosate on hybrid catfish ( × ).

Glyphosate contamination in fresh water is a major problem in agricultural countries. It affects many vital organs in freshwater organisms that are important in the food chain. Hence, the effects of glyphosate on living organism organs are of particular interest.

Spectral fusing Gabor domain optical coherence microscopy based on FPGA processing.

High-resolution imaging using high numerical aperture imaging optics is commonly known to cause a narrow depth of focus, which limits the depth of field in optical coherence tomography (OCT). To achieve semi-invariant high resolution in all directions, Gabor domain optical coherence microscopy (GD-OCM) combines the in-focus regions of multiple cross-sectional images that are acquired while shifting the focal plane of the objective lens. As a result, GD-OCM requires additional processes for in-focus extraction and fusion, leading to longer processing times, as compared with conventional frequency domain OCT (FD-OCT).

Reverberant 3D optical coherence elastography maps the elasticity of individual corneal layers.

The elasticity mapping of individual layers in the cornea using non-destructive elastography techniques advances diagnosis and monitoring of ocular diseases and treatments in ophthalmology. However, transient Lamb waves, currently used in most dynamic optical coherence and ultrasound elastography techniques, diminish the translation of wave speed into shear/Young's modulus. Here, we present reverberant 3D optical coherence elastography (Rev3D-OCE), a novel approach leveraging the physical properties of diffuse fields in detecting elasticity gradients not only in the lateral direction, but also along the depth axis of the cornea.

Comparative study of shear wave-based elastography techniques in optical coherence tomography.

We compare five optical coherence elastography techniques able to estimate the shear speed of waves generated by one and two sources of excitation. The first two techniques make use of one piezoelectric actuator in order to produce a continuous shear wave propagation or a tone-burst propagation (TBP) of 400 Hz over a gelatin tissue-mimicking phantom. The remaining techniques utilize a second actuator located on the opposite side of the region of interest in order to create three types of interference patterns: crawling waves, swept crawling waves, and standing waves, depending on the selection of the frequency difference between the two actuators.

Crawling wave optical coherence elastography.

Elastography is a technique that measures and maps the local elastic property of biological tissues. Aiming for detection of micron-scale inclusions, various optical elastography, especially optical coherence elastography (OCE), techniques have been investigated over the past decade. The challenges of current optical elastography methods include the decrease in elastographic resolution as compared with its parent imaging resolution, the detection sensitivity and accuracy, and the cost of the overall system.

Spectral fusing Gabor domain optical coherence microscopy.

Gabor domain optical coherence microscopy (GD-OCM) is one of many variations of optical coherence tomography (OCT) techniques that aims for invariant high resolution across a 3D field of view by utilizing the ability to dynamically refocus the imaging optics in the sample arm. GD-OCM acquires multiple cross-sectional images at different focus positions of the objective lens, and then fuses them to obtain an invariant high-resolution 3D image of the sample, which comes with the intrinsic drawback of a longer processing time as compared to conventional Fourier domain OCT. Here, we report on an alternative Gabor fusing algorithm, the spectral-fusion technique, which directly processes each acquired spectrum and combines them prior to the Fourier transformation to obtain a depth profile.

Simultaneous estimation of thickness and refractive index of layered gradient refractive index optics using a hybrid confocal-scan swept-source optical coherence tomography system.

A hybrid confocal-scan swept-source optical coherence tomography metrology system was conceived for simultaneous measurements of the refractive index and thickness profiles of polymeric layered gradient refractive index (GRIN) optics. An uncertainty analysis predicts the metrology capability of the system and guides the selection of an optimum working numerical aperture. Experimental results on both a monolithic and a GRIN layered sheet are demonstrated to be in close agreement with theoretical predictions.

Angular scan optical coherence tomography imaging and metrology of spherical gradient refractive index preforms.

The fabrication of high-performance spherical gradient refractive index (S-GRIN) optics requires nondestructive metrology techniques to inspect the samples. We have developed an angular-scan, swept-source-based, Fourier-domain optical coherence tomography (OCT) system centered at 1318 nm with 5 mm imaging depth capable of 180° polar scan and 360° azimuthal scan to investigate polymeric S-GRIN preforms. We demonstrate a method that enables simultaneous mapping of the group optical thickness, physical thickness, the radially-averaged group refractive index, and the transmitted wavefront of the S-GRIN preforms.

Virtual skin biopsy with Gabor Domain optical coherence microscopy.

We report in-vivo volumetric optical coherence microscopy images of the skin, with resolution at the cellular level. With resolution of 2 μm both laterally and axially, structures below the skin as deep as 1 mm may be imaged at various anatomic locations. Custom optical instrumentation was designed, built, and integrated to achieve this unprecedented optical imaging resolution, in three dimensions, at clinically feasible configuration and speed.

Experimental investigations of the scanning functions of galvanometer-based scanners with applications in OCT.

We analyze the three most common profiles of scanning functions for galvanometer-based scanners (GSs): the sawtooth, triangular and sinusoidal functions. They are determined experimentally with regard to the scan parameters of the input signal (i.e.

Cellular resolution optical coherence microscopy with high acquisition speed for in-vivo human skin volumetric imaging.

In this Letter, we report for the first time (to our knowledge) in-vivo volumetric optical coherence microscopy images of skin epidermal cells. We achieved micrometer-class resolution, 2 μm laterally and axially, with an acquisition speed of 23 K A-scans/s and over 90 dB sensitivity to a depth of 1 mm by employing a custom, liquid-lens-based, dynamic-focusing objective, a broadband light source, and a custom, astigmatism-corrected Czerny-Turner spectrometer with a high-speed complementary metal-oxide-semiconductor camera.

Swept-source based, single-shot, multi-detectable velocity range Doppler optical coherence tomography.

Phase-Resolved Doppler Optical Coherence Tomography (PR-DOCT) allows visualization and characterization of the location, direction, velocity, and profile of flow activity embedded in a static sample structure. The detectable Velocity Dynamic Range (VDR) of each particular PR-DOCT system is governed by a detectable Doppler phase shift, a flow angle, and an acquisition time interval used to determine the Doppler phase shift. In general, the lower boundary of the detectable Doppler phase shift is limited by the phase stability of the system, while the upper boundary is limited by the π phase ambiguity.

Doppler imaging with dual-detection full-range frequency domain optical coherence tomography.

Most of full-range techniques for Frequency Domain Optical Coherence Tomography (FD-OCT) reported to date utilize the phase relation between consecutive axial lines to reconstruct a complex interference signal and hence may exhibit degradation in either mirror image suppression performance or detectable velocity dynamic range or both when monitoring a moving sample such as flow activity. We have previously reported a technique of mirror image removal by simultaneous detection of the quadrature components of a complex spectral interference called a Dual-Detection Frequency Domain OCT (DD-FD-OCT) [Opt. Lett.

Assessment of a liquid lens enabled in vivo optical coherence microscope.

The optical aberrations induced by imaging through skin can be predicted using formulas for Seidel aberrations of a plane-parallel plate. Knowledge of these aberrations helps to guide the choice of numerical aperture (NA) of the optics we can use in an implementation of Gabor domain optical coherence microscopy (GD-OCM), where the focus is the only aberration adjustment made through depth. On this basis, a custom-designed, liquid-lens enabled dynamic focusing optical coherence microscope operating at 0.

Gabor-based fusion technique for Optical Coherence Microscopy.

We recently reported on an Optical Coherence Microscopy technique, whose innovation intrinsically builds on a recently reported - 2 microm invariant lateral resolution by design throughout a 2 mm cubic full-field of view - liquid-lens-based dynamic focusing optical probe [Murali et al., Optics Letters 34, 145-147, 2009]. We shall report in this paper on the image acquisition enabled by this optical probe when combined with an automatic data fusion method developed and described here to produce an in-focus high resolution image throughout the imaging depth of the sample.

Dual detection full range frequency domain optical coherence tomography.

It has been shown that frequency domain optical coherence tomography (FD-OCT) systems achieve higher sensitivities compared to time domain optical coherence tomography (OCT) systems. However, the obscure object structure due to the mirror image generated by the Fourier transform is one of the remaining issues in the FD-OCT. We designed and developed what we believe to be a novel full range FD-OCT system that we refer to as the dual detection full range frequency domain optical coherence tomography (DD-FDOCT) that enables the instantaneous retrieval of quadrature components of the complex interferometric signal.

Optical design of a dynamic focus catheter for high-resolution endoscopic optical coherence tomography.

The optical system design of a dynamic focus endoscopic probe for optical coherence tomography is reported. The dynamic focus capability is based on a liquid lens technology that provides variable focus by changing its curvatures in response to an electric field variation. The effects of a cylindrical exit window present, in practice, for a catheter were accounted for.

Collaborative engineering: 3-D optical imaging and gas exchange simulation of in-vitro alveolar constructs.

This paper reports on the computational simulation and modeling of an in vitro alveolar construct system along the optical coherence microscopy (OCM) methods for visualizing engineered tissue. The optical imaging methods will be compared to immunohistochemical light microscopy samples of engineered alveolar constructs. Results show depth images of the alveolar tissue construct for a bilayer construct, as well as predictions of the gas exchange process in a simple model of a bio-reactor hosting the construct.