Assessment of Maternal Macular Pigment Optical Density (MPOD) as a Potential Marker for Dietary Carotenoid Intake during Lactation in Humans.

Pregnancy and lactation can change the maternal nutrient reserve. Non-invasive, quantitative markers of maternal nutrient intake could enable personalized dietary recommendations that improve health outcomes in mothers and infants. Macular pigment optical density (MPOD) is a candidate marker, as MPOD values generally reflect carotenoid intake. We evaluated the association of MPOD with dietary and breastmilk carotenoids in postpartum women. MPOD measurements and dietary intake of five carotenoids were obtained from 80 mothers in the first three months postpartum. Breastmilk samples from a subset of mothers were analyzed to determine their nutrient composition. The association between MPOD and dietary or breastmilk carotenoids was quantitatively assessed to better understand the availability and mobilization of carotenoids. Our results showed that dietary α-carotene was positively correlated with MPOD. Of the breastmilk carotenoids, 13-cis-lutein and trans-lutein were correlated with MPOD when controlled for the total lutein in breastmilk. Other carotenoids in breastmilk were not associated with MPOD. Maternal MPOD is positively correlated with dietary intake of α-carotene in the early postpartum period, as well as with the breastmilk content of lutein. MPOD may serve as a potential marker for the intake of carotenoids, especially α-carotene, in mothers in the early postpartum period.

Simultaneous determination of organophosphorus residues on curry leaf, decontamination through household techniques and risk assessment.

A simple analytical method was developed and validated, as per SANTE 2017 guidelines, for simultaneous determination of 10 organophosphorus residues in curry leaf using gas chromatography with flame photometric detection, and confirmed using gas chromatography-mass spectrometry. Samples were extracted with ethyl acetate and cleaned up with primary secondary amine and graphitized carbon black. Average recoveries were in the range 80-108% with the RSD of less than 8%. The effects of different household cleaning techniques to reduce the concentration of pesticide residues in curry leaf were evaluated and found to remove 2-65% of residues. The method was applied to analyse sample to fresh curry leaf samples, and analysis of potential health risks estimated the residues did not pose a direct hazard. This method could be useful for routine analysis of organophosphorus residue for monitoring purposes.

A photometric stereo-based 3D imaging system using computer vision and deep learning for tracking plant growth.

BACKGROUND: Tracking and predicting the growth performance of plants in different environments is critical for predicting the impact of global climate change. Automated approaches for image capture and analysis have allowed for substantial increases in the throughput of quantitative growth trait measurements compared with manual assessments. Recent work has focused on adopting computer vision and machine learning approaches to improve the accuracy of automated plant phenotyping. Here we present PS-Plant, a low-cost and portable 3D plant phenotyping platform based on an imaging technique novel to plant phenotyping called photometric stereo (PS). RESULTS: We calibrated PS-Plant to track the model plant Arabidopsis thaliana throughout the day-night (diel) cycle and investigated growth architecture under a variety of conditions to illustrate the dramatic effect of the environment on plant phenotype. We developed bespoke computer vision algorithms and assessed available deep neural network architectures to automate the segmentation of rosettes and individual leaves, and extract basic and more advanced traits from PS-derived data, including the tracking of 3D plant growth and diel leaf hyponastic movement. Furthermore, we have produced the first PS training data set, which includes 221 manually annotated Arabidopsis rosettes that were used for training and data analysis (1,768 images in total). A full protocol is provided, including all software components and an additional test data set. CONCLUSIONS: PS-Plant is a powerful new phenotyping tool for plant research that provides robust data at high temporal and spatial resolutions. The system is well-suited for small- and large-scale research and will help to accelerate bridging of the phenotype-to-genotype gap.

Ray tracing in ellipsoidal reflectors for optical biometry of media.

In this paper, an analytical basis of ray tracing for optical biometry of media by ellipsoidal reflectors was developed. A ray-tracing algorithm was created, which involves determining the point of interaction of the incident beam with the ellipsoidal reflector, calculating the direction of the reflected beam, and determining the intersection point of the reflected ray with the second ellipsoid focal plane, taking into account the statistical weight of photons. For imaging in the optical biometry of media by ellipsoidal reflectors, the results of a real experiment and a Monte Carlo simulation for chicken muscle tissue samples of different thicknesses for the wavelength of 632.8 nm are used.

Validation of QuEChERS based method for determination of fenitrothion residues in tomatoes by gas chromatography-flame photometric detector: Decline pattern and risk assessment.

A simple and rapid gas chromatography with flame photometric detector (GC-FPD) determination method was developed to detect residue levels and investigate the dissipation pattern and safe use of fenitrothion in tomatoes. A modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) using an ethyl acetate-based extraction, followed by a dispersive solid-phase extraction (d-SPE) with primary-secondary amine (PSA) and graphite carbon black (GCB) for clean up, was applied prior to GC-FPD analysis. The method showed satisfactory linearity, recovery and precision. The limits of detection (LOD) and quantification (LOQ) were 0.005 and 0.01mg/kg, respectively. The residue levels of fenitrothion were best described by first order kinetics with a half-life of 2.2days in tomatoes. The potential health risks posed by fenitrothion were not significant, based on supervised residue trial data. The current findings could provide guidance for safe and reasonable use of fenitrothion in tomatoes and prevent health problems to consumers.

Quantitative surface topography assessment of directly compressed and roller compacted tablet cores using photometric stereo image analysis.

Surface topography, in the context of surface smoothness/roughness, was investigated by the use of an image analysis technique, MultiRay™, related to photometric stereo, on different tablet batches manufactured either by direct compression or roller compaction. In the present study, oblique illumination of the tablet (darkfield) was considered and the area of cracks and pores in the surface was used as a measure of tablet surface topography; the higher a value, the rougher the surface. The investigations demonstrated a high precision of the proposed technique, which was able to rapidly (within milliseconds) and quantitatively measure the obtained surface topography of the produced tablets. Compaction history, in the form of applied roll force and tablet punch pressure, was also reflected in the measured smoothness of the tablet surfaces. Generally it was found that a higher degree of plastic deformation of the microcrystalline cellulose resulted in a smoother tablet surface. This altogether demonstrated that the technique provides the pharmaceutical developer with a reliable, quantitative response parameter for visual appearance of solid dosage forms, which may be used for process and ultimately product optimization.

Quantitative assessment of the impact of blood pulsation on images of the pupil in infrared light.

Pulsation in the blood vessels of the eye has a big impact on the dynamics of the entire eyeball and its individual elements. Blood pulsation in the retina can be recorded by the pupil, whose size is also subject to dynamic changes. The study involved synchronous measurements of pupil size using a high-speed camera, and blood pulsation using a pulse oximeter placed on the ear lobe. In addition, there were no metrologically significant differences in the phase shift between the average brightness of the individual pupil quadrants. Blood pulsation in other ocular tissues can affect the dynamics of the optical properties of the eye. As demonstrated in this paper, it affects the pupil behavior and its parameters to a considerable extent.

Integration of novel low-cost colorimetric, laser photometric, and visual fluorescent techniques for rapid identification of falsified medicines in resource-poor areas: application to artemether-lumefantrine.

The availability of falsified antimalarial drugs can be reduced with effective drug regulatory agencies and proper enforcement. Fundamental to these agencies taking action, rapid identification must be made as soon as they appear in the market place. Since falsified antimalarials occur mostly in developing countries, performing drug analysis presents itself with unique challenges. A fundamental factor in choosing a useful technique is affordability and simplicity. Therefore, we suggest a three-tiered drug evaluation strategy for identifying a falsified drug in resource-poor areas. Tier I is a simple comparison of a tablet's weight and dimensions with official specifications. Tier II uses inexpensive photometric devices (laser and fluorescence) to evaluate a tablet. Suspicious samples from Tier I and II assessments are then subjected to a colorimetric assay for active ingredients identification and quantification. In this article, we evaluate a novel colorimetric assay for the simultaneous assessment of both lumefantrine and artemether in co-formulated Coartem™ tablets, and integrate the method with two novel, low-cost, fluorescence and laser photometric devices. Image analysis software is used for the assessments. Although artemether-lumefantrine is used as an example, the strategy may be adapted to other medicines.

A practical approach to glare assessment for train cabs.

The assessment of glare is a key consideration in the design of a railway driver's cab. However, unlike assessment of other factors, such as forward visibility, there are no standardised approaches for performing assessments of glare. This paper describes an approach for assessing the impact of glare in a full size mock-up of a railway cab. While it is unrealistic to evaluate every possible lighting condition that may potentially occur in the vehicle cab in service, a pragmatic and practical approach is taken to provide a good level of indicative information about the cab design's likely glare performance. This involves assessing internal light sources, such as internal lights and illuminated controls, and simulating external light sources (e.g. the sun, other trains' headlights) by illuminating the cab mock up windscreen, side and door windows with a single light source manually located in a sequence of discrete positions and orientations and assessing the resulting glare impacts. The paper describes a structured process for assessing and recording the impact of glare and recommending mitigations.

Review of diverse optical fibers used in biomedical research and clinical practice.

Optical fiber technology has significantly bolstered the growth of photonics applications in basic life sciences research and in biomedical diagnosis, therapy, monitoring, and surgery. The unique operational characteristics of diverse fibers have been exploited to realize advanced biomedical functions in areas such as illumination, imaging, minimally invasive surgery, tissue ablation, biological sensing, and tissue diagnosis. This review paper provides the necessary background to understand how optical fibers function, to describe the various categories of available fibers, and to illustrate how specific fibers are used for selected biomedical photonics applications. Research articles and vendor data sheets were consulted to describe the operational characteristics of conventional and specialty multimode and single-mode solid-core fibers, double-clad fibers, hard-clad silica fibers, conventional hollow-core fibers, photonic crystal fibers, polymer optical fibers, side-emitting and side-firing fibers, middle-infrared fibers, and optical fiber bundles. Representative applications from the recent literature illustrate how various fibers can be utilized in a wide range of biomedical disciplines. In addition to helping researchers refine current experimental setups, the material in this review paper will help conceptualize and develop emerging optical fiber-based diagnostic and analysis tools.

Assessment of SIAscopy in the triage of suspicious skin tumours.

BACKGROUND/PURPOSE: Spectrophotometric Intracutaneous Analysis (SIAscopy) is a non-invasive, computerized technique for the diagnosis of pigmented skin tumours. The analysis is based on the evaluation of skin chromophores, i.e. melanin, haemoglobin and collagen within the epidermis and papillary dermis. Our aim was to assess the diagnostic validity of SIAscopy in the detection of melanoma and non-melanoma skin cancers compared to the clinical-dermoscopic diagnosis and the histopathologic results of the excised lesions. METHODS: In total, 188 lesions of 180 patients were examined by dermoscopy and SIAscopy. A SIAscopy scoring system was first compared with the clinical-dermoscopic diagnosis and then with the histopathologic diagnosis of the excised lesions. RESULTS: With respect to the clinical-dermoscopic evaluation, SIAscopy had sensitivity and specificity values of 85.7% and 65.4% respectively. Of the 188 evaluated lesions, 44 were excised with histopathologic examination revealing 31 malignant tumours, including 18 melanomas. With respect to histopathology SIAscopy had a sensitivity of 83.9%. Seven of the 13 benign excised lesions were scored as malignant by SIAscopy resulting in a specificity of 46.1%. CONCLUSION: SIAscopy cannot replace the standard of care in skin cancer diagnosis, which includes clinical and dermoscopic examination. However, considering that the technique does not require specific training and expertise, it might represent an additional, relatively cost-effective tool to select lesions for referral.

A cost-effective solution for the reliable determination of cell numbers of microorganisms in liquid culture.

The concentration of microorganisms in growth medium is an important parameter in microbiological research. One of the approaches to determine this parameter is based on the physical interaction of small particles with light that results in light scattering. Table-top spectrophotometers can be used to determine the scattering properties of a sample as a change in light transmission. However, a portable, reliable, and maintenance-free instrument that can be built from inexpensive parts could provide new research opportunities. In this report, we show how to build such an instrument. This instrument consists of a low power monochromatic light-emitting diode, a monolithic photodiode, and a microcontroller. We demonstrate that this instrument facilitates the precise determination of cell concentrations for the bacteria Escherichia coli and Pseudomonas aeruginosa as well as the cyanobacterium Synechocystis sp. PCC 6803 and the green alga Chlamydomonas reinhardtii.

Effects of enamel abrasion, salivary pellicle, and measurement angle on the optical assessment of dental erosion.

The present study assessed the effects of abrasion, salivary proteins, and measurement angle on the quantification of early dental erosion by the analysis of reflection intensities from enamel. Enamel from 184 caries-free human molars was used for in vitro erosion in citric acid (pH 3.6). Abrasion of the eroded enamel resulted in a 6% to 14% increase in the specular reflection intensity compared to only eroded enamel, and the reflection increase depended on the erosion degree. Nevertheless, monitoring of early erosion by reflection analysis was possible even in the abraded eroded teeth. The presence of the salivary pellicle induced up to 22% higher reflection intensities due to the smoothing of the eroded enamel by the adhered proteins. However, this measurement artifact could be significantly minimized (p<0.05) by removing the pellicle layer with 3% NaOCl solution. Change of the measurement angles from 45 to 60 deg did not improve the sensitivity of the analysis at late erosion stages. The applicability of the method for monitoring the remineralization of eroded enamel remained unclear in a demineralization/remineralization cycling model of early dental erosion in vitro.

Assessment of wavelength dependent complex refractive index of strongly light absorbing liquids.

A practical measurement procedure for the determination of the complex refractive index of strongly absorbing liquids within a finite spectral range was developed. The method is based on separate measurements of reflectance and transmittance of the liquid sample, a property of dispersion and absorption, and exploitation of Fresnel's theory. The advantage of the method is that the knowledge of the layer thickness of the light absorbing medium, which is required typically in transmittance measurements, is not needed. In addition, both measurements, the transmittance and the reflectance, were accomplished with one spectrophotometer using a home-built reflectometer and without any sample dilution. The method is validated by numerical simulation using the Lorentz model for permittivity of an insulator, and also by experimental data obtained from three strongly absorbing offset inks, namely magenta, yellow and cyan.

Assessment of macular pigment optical density (MPOD) in patients with unilateral wet age-related macular degeneration (AMD).

PURPOSE: To compare the macular pigment optical density (MPOD) of patients with unilateral wet age-related macular degeneration (AMD) with the MPOD of bilateral dry AMD patients and healthy elderly individuals. METHODS: The MPOD of 34 patients with unilateral wet AMD was measured in their fellow eye that had the dry form of the disease (study group). The MPOD of the study group was compared with the MPOD of 33 patients with bilateral dry AMD (patients' control group) and 35 elderly subjects without any signs of retinal disease (control group). None of the subjects was under carotenoid supplementation. The MPOD was measured with Heterochromatic Flicker Photometry [QuantifEYE™- MPS 9000 (ZeaVision(©))]. The statistical package SPSS v 17.0 was used for the analysis. RESULTS: The overall mean MPOD was 0.52 (SD 0.15). Patients with unilateral wet AMD have significantly higher levels of MPOD in their fellow eye compared with patients with bilateral dry AMD (0.58 versus 0.48, p = 0.026). Mean MPOD of patients with bilateral dry AMD does not differ significantly from that of healthy elderly subjects (0.48 versus 0.50, p = 0.865). In this population sample, no correlation with age was observed, while women have slightly but significantly higher levels of MPOD (0.55 versus 0.49, p = 0.029). CONCLUSION: In the present study, the mean MPOD at the fellow eye of patients with unilateral wet AMD was found to be significantly higher than that of patients with bilateral dry AMD, while no other significant difference emerged between groups. Further investigation is demanded to clarify the role of macular pigment in AMD progression.

Hemoglobin determination with paired emitter detector diode.

Two ordinary green light-emitting diodes used as light emitter and detector coupled with simple voltmeter form a complete, cost-effective prototype of a photometric hemoglobinometer. The device has been optimized for cuvette assays of total hemoglobin (Hb) in diluted blood using three different chemical methods recommended for the needs of clinical analysis (namely Drabkin, lauryl sulfate, and dithionite methods). The utility of developed device for real analytics has been validated by the assays of total Hb content in human blood. The results of analysis are fully compatible with those obtained using clinically recommended method and clinical analyzer.

Assessment of MERIS reflectance data as processed with SeaDAS over the European seas.

The uncertainties associated with MERIS remote sensing reflectance (RRS) data derived from the SeaWiFS Data Analysis System (SeaDAS) are assessed with field observations. In agreement with the strategy applied for other sensors, a vicarious calibration is conducted using in situ data from the Marine Optical BuoY offshore Hawaii, and leads to vicarious adjustment factors departing from 1 by 0.2% to 1.6%. The three field data sets used for validation have been collected at fixed stations in the northern Adriatic Sea and the Baltic Sea, and in a variety of European waters in the Baltic, Black, Mediterranean and North Seas. Excluding Baltic waters, the mean absolute relative difference |ψ| between satellite and field data is 10-14% for the spectral interval 490-560 nm, 16-18% at 443 nm, and 24-26% at 413 nm. In the Baltic Sea, the |ψ| values are much higher for the blue bands characterized by low RRS amplitudes, but similar or lower at 560 and 665 nm. For the three validation sets, the root-mean-square differences decrease from approximately 0.0013 sr-1 at 413 nm to 0.0002 sr-1 at 665 nm, and are found similar or lower than those obtained for SeaWiFS or MODIS-Aqua. As derived from SeaDAS, the RRS records associated with these three missions thus provide a multi-mission data stream of consistent accuracy.

The Macular Assessment Profile test - a new VDU-based technique for measuring the spatial distribution of the macular pigment, lens density and rapid flicker sensitivity.

The measurement of macular pigment optical density (MPOD) in the eye is often carried out using optical techniques based on heterochromatic flicker photometry (HFP). These require the use of two spectrally-narrow beams, one at the wavelength of maximum absorption of the macular pigment (MP) and the other in the long wavelength region of the visible spectrum where MP absorption is negligible. A new technique for the measurement of MPOD spatial profiles has been developed by overcoming the current shortcomings associated with the use of visual displays. The new Macular Assessment Profile (MAP) test makes use of a 'notch' filter and a photometric model to measure and compute the peak MPOD value. Two other useful parameters are also computed from the same measurements. These describe the subject's sensitivity to rapid flicker and the absorption of blue light by the lens. MPOD profiles, lens density, rapid flicker sensitivity, and red/green (RG) and yellow/blue (YB) colour thresholds were measured in 54 normal subjects aged 18-61 years. The results confirm previous findings on ageing effects and demonstrate the complete absence of correlation between MPOD and the subject's YB chromatic thresholds. In contrast, RG chromatic sensitivity improves with higher levels of MPOD.

Deep-tissue dynamic monitoring of decubitus ulcers: wound care and assessment.

The use of deep-tissue multiwavelength imaging is of paramount importance in clinical settings as a noninvasive solution to identify and monitor the progression of decubitus ulcers. A point-of-care multiwavelength imager is being developed, whose utility results from the provision of important physiological characteristics and blood flow metrics via analysis of deep-tissue response to light. The noninvasive real-time monitoring and analysis of tissue focusing on wound imaging is integral, because it allows for quantitative in situ measurements that characterize tissue to assess the progress of either tissue healing or necrosis.

Whole blood reflectance for assessment of hematologic condition and detection of angiographic contrast media.

We present simple whole blood reflectance analyses in the range 500-900 nm, using intact whole blood to simultaneously quantify hematocrit and oxygen saturation from a single spectral reading. We applied these results for the development of an intravascular catheter-based reflectance sensing system to detect and remove contrast media injected during angiography so as to reduce the risk of complications associated with the injected contrast media. We further tested the practicality of the optical detection of angiographic contrast media in a pilot animal study in vivo. We successfully demonstrated the feasibility of real-time in vivo contrast detection and removal during angiography. Our simple method for the detection and removal of angiographic contrast media will facilitate the development of intravascular optical sensing systems.