Performance of primary diagnostic monitors (PDMs) over time.

In this work, we evaluated the change of primary monitor characteristics in two consecutive years. Sixty-six primary monitors were included in the analysis. The monitors were located at radiology physicians' offices and radiology reading rooms. All primary monitors were equipped with the manufacturer's built-in photometers and connected to the BarcoMediCalQA web service for manual and automatic quality control measurements. External photometer/illuminance meter (RaySafe Solo Light) was used to measure the luminance values. Measured luminance values of the TG18LN1-18 and TG18UNL80 test patterns were used to evaluate the primary monitors performance. In a comparison of the quality assurance (QA) measurement results for the same monitors that were performed within 2 years, the luminance of 25 displays remained statistically the same (P > 0.01). The luminance of 17 displays decreased (P < 0.01) in 2017 when compared with 2016, the luminance of 24 displays increased (P < 0.01) in 2017 when compared with 2016. For the annual measurements of the MLD in 2016 and 2017, 25 out of 66 displays showed a decrease of MLD values in 2017 compared with the same measurements in 2016 and 41 displays showed an increase of MLD in 2017. All tested primary displays had the MLD value less than 17.2%. The mean value of illuminance measured in 2016 was 5.8 lux ± 3.1 lux. In 2017, the mean value of illuminance measured was 8.7 lux ± 5.3 lux. Although it is expected that monitors luminance values will decrease over time, we found displays with increased luminance. This is possibly due to the multiple monitor calibrations that were performed between two annual monitor QA tests. Based on the findings of this work, more efficient display QA programs with a shorter time interval than 1 year are needed.

[Hygienic and environmental problems of energy-saving illumination in urbanization of Crimea].

The article considers the problems offloodlights pollution in the territory of Crimea due to the work of illumination led equipment of the key elements of the international transport artery "China-Europe". There was performed a qualitative assessment of characteristics of led floodlights pollution on the example of the sea surface of the transport crossing through the Kerch Strait. Ichthyologists and oceanographers were shown to estimate the amount of phytoplankton biomass based on sunlight illumination. The excess dose of blue light in the spectrum of led lighting was established to have an impact on phytoplankton greater than solar and lunar light, creating preconditions for the increase of biological mass of phytoplankton and consequently to the formation of the "stern stock". Arising from additional phytoplankton biomass can significantly influence on the schedule offish migration in waters of the Kerch Strait, the biomass of mosquitoes and midges, which are prey for amphibians and birds. The decline of the both light pollution and its negative impact on fauna andflora requires the development of semiconductor sources of white light with a biologically adequate spectrum in the framework of the "Lighting of the lighting equipment of Crimea".

Traceable terahertz power measurement from 1 THz to 5 THz.

The metrology institute in Germany, the Physikalisch-Technische Bundesanstalt (PTB), calibrates the spectral responsivity of THz detectors at 2.52 THz traceable to International System of Units. The Terahertz detector calibration facility is equipped with a standard detector calibrated against a cryogenic radiometer at this frequency. In order to extend this service to a broader spectral range in the THz region a new standard detector was developed. This detector is based on a commercial thermopile detector. Its absorber was modified and characterized by spectroscopic methods with respect to its absorptance and reflectance from 1 THz to 5 THz and at the wavelength of a helium-neon laser in the visible spectral range. This offers the possibility of tracing back the THz power responsivity scale to the more accurate responsivity scale in the visible spectral range and thereby to reduce the uncertainty of detector calibrations in the THz range significantly.

Maximum likelihood method for calibration of Mueller polarimeters in reflection configuration.

We address calibration of Mueller polarimeters in the presence of noise. We compare an extension of the eigenvalue calibration method (ECM) and a maximum likelihood (ML) method. The performances of these two calibration methods are investigated with numerical simulations and real experiments on a broadband infrared polarimeter. It is found that the ML method is superior to the extended ECM in terms of calibration precision and can be used at lower signal-to-noise ratio.

External evaluation of the Dimension Vista 1500® intelligent lab system.

BACKGROUND: Dimension Vista® analyzer combines four technologies (photometry, nephelometry, V-LYTE® integrated multisensor potentiometry, and LOCI® chemiluminescence) into one high-throughput system. METHODS: We assessed analytical performance of assays routinely performed in our emergency laboratory according to the VALTEC protocol, and practicability. RESULTS: Precision was good for most parameters. Analytical domain was large and suitable for undiluted analysis in most clinical settings encountered in our hospital. Data were comparable and correlated to our routine analyzers (Roche Modular DP®, Abbott AXSYM®, Siemens Dimension® RxL, and BN ProSpec®). Performance of nephelometric and LOCI modules was excellent. Functional sensitivity of high-sensitivity C-reactive protein and cardiac troponin I were 0.165 mg/l and 0.03 ng/ml, respectively (coefficient of variation; CV < 10%). The influence of interfering substances (i.e., hemoglobin, bilirubin, or lipids) was moderate, and Dimension Vista® specifically alerted for interference according to HIL (hemolysis, icterus, lipemia) indices. Good instrument performance and full functionality (no reagent or sample carryover in the conditions evaluated, effective sample-volume detection, and clot detection) were confirmed. Simulated routine testing demonstrated excellent practicability, throughput, ease of use of software and security. CONCLUSION: Performance and practicability of Dimension Vista® are highly suitable for both routine and emergency use. Since no volume detection and thus no warning is available on limited sample racks, pediatric samples require special caution to the Siemens protocol to be analyzed in secured conditions. Our experience in routine practice is also discussed, i.e., the impact of daily workload, "manual" steps resulting from dilutions and pediatric samples, maintenances, flex hydration on instrument's performance on throughput and turnaround time.

Guidelines for 1D-periodic surface microstructures for antireflective lenses.

Antireflective properties of one-dimensional periodically microstructured lens surfaces (refractive index 1.5) are studied with the Green's function surface integral equation method, and design guidelines are obtained. Special attention is given to the requirement of having practically all incident light transmitted in the fundamental transmission diffraction order. The effect of the presence of higher transmission diffraction orders is studied to determine if such more easily fabricated structures will be useful. The decrease of optimum fill factor of a periodic array of subwavelength ridges with structure period is explained as a waveguiding effect. Near-fields are calculated illustrating standing-wave interference and waveguiding effects for ridge structures, and adiabatic field transformation for tapered structures, including evanescent near-fields in in- and out-coupling regions. The antireflective properties of tapered geometries are considered for a wide range of angles of light incidence. It is found that while the reflection can be very small this rarely implies high transmission into the fundamental transmission diffraction order when higher-order transmission diffraction orders exist. This leads to the guideline that for visible and normally incident light the surface structure period should not be larger than ~300 nm, and a smaller period is needed in the case of oblique light incidence.

Intercalibration of infrared channels of polar-orbiting IRAS/FY-3A with AIRS/Aqua data.

This work intercalibrated the infrared window channels 8 (12.47 microm), 9 (11.11 microm) and 19 (3.98 microm) of the InfraRed Atmospheric Sounder (IRAS) aboard the Chinese second generation polar-orbiting meteorological satellite FengYun 3A (FY-3A) with high spectral resolution data acquired by the Atmospheric InfraRed Sounder (AIRS) aboard Aqua. A North Pole study area was selected according to the IRAS and AIRS' viewing geometry. The IRAS/FY-3A L1 data and AIRS/Aqua 1B Infrared geolocated and calibrated radiances (AIRIBRAD) in July of 2008 were used in this work. A sub-pixel registration method was developed and applied to the IRAS and AIRS images to improve the intercalibration accuracy. The co-located measurement pairs were picked out with absolute Viewing Zenith Angle differences less than 5 degrees (|Delta VZA|<5 degrees), absolute Viewing Azimuth Angle differences less than 90 degrees (|Delta VAA|<90 degrees) and absolute time differences less than 15 min (|Delta T|<15'). The results reveal that the convolved AIRS/Aqua measurements are highly linearly related to the IRAS/FY-3A measurements with correlation coefficients greater than 0.93, and calibration discrepancies exist between IRAS and AIRS channels indeed. When the brightness temperatures in IRAS/FY-3A channels change from 230.0 K to 310.0 K, the AIRS-IRAS temperature adjustment linearly varies from -3.3 K to 1.7 K for IRAS/FY-3A channel 8, from -2.9 K to 2.6 K for IRAS/FY-3A channel 9, and from -5.3 K to 1.1 K for IRAS/FY-3A channel 19.

Using 3D differential forms to characterize a pigmented lesion in vivo.

BACKGROUND/PURPOSE: After the formulation of ABCD rules, many new feature extraction methods are emerging to describe the asymmetry, border irregularity, color variation and diameter of malignant melanoma. In this paper, a new research direction orthogonal to ABCD rules that characterizes 3D local disruption of skin surfaces to realize automatic recognition of melanoma is described. METHODS: This paper examines 3D differential forms of skin surfaces to characterize the local geometrical properties of melanoma. Firstly, 3D data of skin surfaces are obtained using a photometric stereo device. Then differential forms of lesion surfaces are determined to describe the geometrical texture patterns involved. Using only these geometrical features, a simple least-squared error-based linear classifier can be constructed to realize the classification of malignant melanomas and benign lesions. RESULTS: As with the 3D data of 35 melanoma and 66 benign lesion samples collected from local pigmented lesion clinics, the optimal sensitivity and specificity of the constructed linear classifier are 71.4% and 86.4%, respectively. The total area enclosed by the corresponding receiver operating characteristics curve is 0.823. CONCLUSION: This study indicates that differential forms obtained from 3D data are very promising in characterizing melanoma. Combining these features with other skin features such as border irregularity and color variation might further improve the accuracy and reliability of the automatic diagnosis of melanoma.

Development and Validation of an Analytical Method to Quantitate Tris(chloroisopropyl)phosphate in Rat and Mouse Plasma using Gas Chromatography with Flame Photometric Detection.

Tris(chloropropyl)phosphate (TCPP) is an organophosphorus flame retardant (OPFR) and plasticizer increasingly used in consumer products and as a replacement for brominated flame retardants. Commercially available TCPP is a mixture of four structural isomers the most abundant of which is tris(1-chloro-2-propyl)phosphate (TCPP-1). Although there is a widespread use of TCPP and potential for human exposure, there is limited data on the safety or toxicity of TCPP. The National Toxicology Program is conducting long-term studies to examine the toxicity of the TCPP in rats after lifetime exposure, including perinatal oral exposure. Quantitative estimates of internal dose are essential to interpret toxicological findings in rodents. To aid in this, a method was fully validated to quantitate the most abundant isomer, TCPP-1, in female Harlan Sprague Dawley (HSD) rat and B6C3F1 mouse plasma with partial validation in male rat plasma, and male and female mouse plasma. The method used protein precipitation using trichloroacetic acid followed by the extraction with toluene, and analysis by gas chromatography with flame photometric detection. The performance of the method was evaluated over 5-70 ng TCPP-1/mL plasma. The method was linear (r ≥ 0.99), accurate (inter-day relative error: ≤ ± -7.2) and precise (inter-batch relative standard deviation: ≤27.5%). The validated method has lower limits of quantitation and detection of ~5 and 0.9 ng/mL, respectively, in female HSD rat plasma and can be used on samples as small as 50 µL demonstrating the applicability to plasma samples from toxicology studies.

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.

Analysis of the possibility of analog detectors calibration by exploiting stimulated parametric down conversion.

Spontaneous parametric down conversion (SPDC) has been largely exploited as a tool for absolute calibration of photon-counting detectors, i.e detectors registering very small photon fluxes. In [J. Opt. Soc. Am. B 23, 2185 (2006)] we derived a method for absolute calibration of analog detectors using SPDC emission at higher photon fluxes, where the beam is seen as a continuum by the detector. Nevertheless intrinsic limitations appear when high-gain regime of SPDC is required to reach even larger photon fluxes. Here we show that stimulated parametric down conversion allow one to avoid this limitation, since stimulated photon fluxes are increased by the presence of the seed beam.

Towards a uniform specification of light therapy devices for the treatment of affective disorders and use for non-image forming effects: Radiant flux.

BACKGROUND: For treating affective disorders like SAD, light therapy is used although the underlying mechanism explaining this success remains unclear. To accelerate the research on defining the light characteristics responsible for inducing a specific effect a uniform manner for specifying the irradiance at the eye should be defined. This allows a genuine comparison between light-affect studies. An important factor impacting the irradiance at the eye are the radiant characteristics of the used light therapy device. METHOD: In this study the radiant fluxes of five different light therapy devices were measured. The values were weighted against the spectral sensitivity of the five photopigments present in the human eye. A measurement was taken every five minutes to control for a potential stabilizing effect. RESULTS: The results show that all five devices show large differences in radiant flux. The devices equipped with blue LED lights have a much lower spectral radiant flux than the devices equipped with a fluorescent light source or a white LED. The devices with fluorescent lamps needed 30 min to stabilize to a constant radiant flux. LIMITATIONS: In this study only five devices were measured. Radiant flux is just the first step to identify uniform specifications for light therapy devices. CONCLUSIONS: It is recommended to provide all five α-opic radiant fluxes. Preferably, the devices should come with a spectral power distribution of the radiant flux. For the devices equipped with a fluorescent lamp it is recommended to provide information on the stabilization time.

Random uncertainty of photometric determination of hemolysis index on the Abbott Architect c16000 platform.

BACKGROUND: Automatic photometric determination of the hemolysis index (HI) on serum and plasma samples is central to detect potential interferences of in vitro hemolysis on laboratory tests. When HI is above an established cut-off for interference, results may suffer from a significant bias and undermine clinical reliability of the test. Despite its undeniable importance for patient safety, the analytical performance of HI estimation is not usually checked in laboratories. Here we evaluated for the first time the random source of measurement uncertainty of HI determination on the two Abbott Architect c16000 platforms in use in our laboratory. METHODS: From January 2016 to September 2017, we collected data from daily photometric determination of HI on a fresh-frozen serum pool with a predetermined HI value of ~100 (corresponding to ~1g/L of free hemoglobin). Monthly and cumulative CVs were calculated. RESULTS: During 21months, 442 and 451 measurements were performed on the two platforms, respectively. Monthly CVs ranged from 0.7% to 2.7% on c16000-1 and from 0.8% to 2.5% on c16000-2, with a between-platform cumulative CV of 1.82% (corresponding to an expanded uncertainty of 3.64%). Mean HI values on the two platforms were just slightly biased (101.3 vs. 103.1, 1.76%), but, due to the high precision of measurements, this difference assumed statistical significance (p<0.0001). CONCLUSIONS: Even though no quality specifications are available to date, our study shows that the HI measurement on Architect c16000 platform has nice reproducibility that could be considered in establishing the state of the art of the measurement.

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.

Massively parallel WRNN reconstructors for spectrum recovery in astronomical photometrical surveys.

The investigation of solar-like oscillations for probing star interiors has enjoyed a tremendous growth in the last decade. Once observations are over, the most notable difficulties in properly identifying the true oscillation frequencies of stars are due to the gaps in the observation time-series and the intrinsic stellar granulation noise. This paper presents an innovative neuro-wavelet reconstructor for the missing data of photometric signals. Firstly, gathered data are transformed using wavelet operators and filters, and this operation removes granulation noise, then we predict missing data by a composite of two neural networks, which together allow a "forward and backward" reconstruction. This resulting error is greatly lower than the absolute a priori measurement error. The devised reconstruction approach gives a signal that is better suited to be Fourier transformed when compared with other existing methods.

Comparison of Acid Titration, Conductivity, Flame Photometry, ICP-MS, and Accelerated Lamellae Formation Techniques in Determining Glass Vial Quality.

Certain types of glass vials used as primary containers for liquid formulations of biopharmaceutical drug products have been observed with delamination that produced small glass like flakes termed lamellae under certain conditions during storage. The cause of this delamination is in part related to the glass surface defects, which renders the vials susceptible to flaking, and lamellae are formed during the high-temperature melting and annealing used for vial fabrication and shaping. The current European Pharmacopoeia method to assess glass vial quality utilizes acid titration of vial extract pools to determine hydrolytic resistance or alkalinity. Four alternative techniques with improved throughput, convenience, and/or comprehension were examined by subjecting seven lots of vials to analysis by all techniques. The first three new techniques of conductivity, flame photometry, and inductively coupled plasma mass spectrometry measured the same sample pools as acid titration. All three showed good correlation with alkalinity: conductivity (R(2) = 0.9951), flame photometry sodium (R(2) = 0.9895), and several elements by inductively coupled plasma mass spectrometry [(sodium (R(2) = 0.9869), boron (R(2) = 0.9796), silicon (R(2) = 0.9426), total (R(2) = 0.9639)]. The fourth technique processed the vials under conditions that promote delamination, termed accelerated lamellae formation, and then inspected those vials visually for lamellae. The visual inspection results without the lot with different processing condition correlated well with alkalinity (R(2) = 0.9474). Due to vial processing differences affecting alkalinity measurements and delamination propensity differently, the ratio of silicon and sodium measurements from inductively coupled plasma mass spectrometry was the most informative technique to assess overall vial quality and vial propensity for lamellae formation. The other techniques of conductivity, flame photometry, and accelerated lamellae formation condition may still be suitable for routine screening of vial lots produced under consistent processes. LAY ABSTRACT: Recently, delamination that produced small glass like flakes termed lamellae has been observed in glass vials that are commonly used as primary containers for pharmaceutical drug products under certain conditions during storage. The main cause of these lamellae was the quality of the glass itself related to the manufacturing process. Current European Pharmacopoeia method to assess glass vial quality utilizes acid titration of vial extract pools to determine hydrolytic resistance or alkalinity. As alternative to the European Pharmacopoeia method, four other techniques were assessed. Three new techniques of conductivity, flame photometry, and inductively coupled plasma mass spectrometry measured the vial extract pool as acid titration to quantify quality, and they demonstrated good correlation with original alkalinity. The fourth technique processed the vials under conditions that promote delamination, termed accelerated lamellae formation, and the vials were then inspected visually for lamellae. The accelerated lamellae formation technique also showed good correlation with alkalinity. Of the new four techniques, inductively coupled plasma mass spectrometry was the most informative technique to assess overall vial quality even with differences in processing between vial lots. Other three techniques were still suitable for routine screening of vial lots produced under consistent processes.

Comparative Analysis of Anterior Chamber Flare Grading between Clinicians with Different Levels of Experience and Semi-automated Laser Flare Photometry.

PURPOSE: To assess correlation for anterior chamber flare grading between clinicians with different levels of experience and with semi-automated flare reading in a cohort of patients with heterogeneous uveitic entities. METHODS: Fifty-nine observations from 36 patients were recorded and analyzed for statistical association. In each patient, flare was assessed objectively using the Kowa FM-700 laser flare photometer, and subjective masked grading by two clinicians was performed. RESULTS: The study demonstrated disparity in flare readings between clinical graders with one step disagreement in clinical grading in 26 (44.06%) eyes (p < 0.001) and concordance between the flare readings by experienced grader and flare photometry. After review of semi-automated flare readings, management was changed in 11% of the patients. CONCLUSION: Laser flare photometry can be a valuable tool to remove the observer bias in grading flare for selected cohort of uveitis patients. It can be further applied to titrate therapy in intraocular inflammation.

Instrument Quality Control.

Well-defined quality control (QC) processes are used to determine whether a certain procedure or action conforms to a widely accepted standard and/or set of guidelines, and are important components of any laboratory quality assurance program (Popa-Burke et al., J Biomol Screen 14: 1017-1030, 2009). In this chapter, we describe QC procedures useful for monitoring the accuracy and precision of laboratory instrumentation, most notably automated liquid dispensers. Two techniques, gravimetric QC and photometric QC, are highlighted in this chapter. When used together, these simple techniques provide a robust process for evaluating liquid handler accuracy and precision, and critically underpin high-quality research programs.

Calibration of the Nuclear Associates 07-621 precision photometer.

The spectral response of the Nuclear Associates 07-621 photometer has been measured over an extended range (400-990 nm). The measurements reveal that the photometer shows large deviations from the standard CIE photopic response. In particular it has considerable excess response in the red (650-780 nm) and in the near infra red (780-990 nm). Although the instrument is claimed to have a photometric accuracy of +/- 7% this is only realised when measuring sources, such as tungsten lamps, which are rich in the red and near infra red regions of the spectrum. When used with sources, such as fluorescent lamps, which contain little radiation in the range 650-1200 nm it underestimates the light output by approximately 20%. As a consequence this photometer can only be used in radiology QA for such tasks as measuring view box luminance if the appropriate correction factor is used. This factor should be determined at the outset by comparing the Nuclear Associates 07-621 with a high quality photometer using the same type of light that is emitted by the boxes.