Chromatic Analysis Research Articles

Colorimetric Determination of Urinary Creatinine in Proteinuria Patients by Chromaticity Analysis of Gold Nanoparticle Colloidal Solutions.

Several scientific works have reported the use of colloidal gold nanoparticle (AuNP) solutions as a colorimetric probe for creatinine detection. Nonetheless, urinary protein is one of the primary chemical components that can interfere with creatinine detection. In this work, we developed a colorimetric probe using AuNP colloidal solution to detect creatinine in the urine of proteinuria patients. A microchamber array was prepared to minimize the sample volume and was used to simultaneously perform spectral recording and image acquisition of several samples. The analyzed volume for each sample was 15 μL. A camera coupled with liquid crystal tunable filters was used to record hyperspectral images, and the signals were then converted to localized surface plasmon resonance (LSPR) spectra. Color changes in the AuNP colloidal solution in the presence of varying concentrations of creatinine and human serum albumin (HSA) indicated different features and could be detected by a hyperspectral imaging technique. The relevant concentration ranges of creatinine and HSA were 5 - 200 and 50 - 250 mg dL-1, respectively. Furthermore, a smartphone camera was adopted to record a color mapping image of the AuNP colloidal solution in the presence of creatinine and HSA at these concentration ranges. Contour plots of red and blue chromaticity levels from color mappings were produced, and 2D fitting equations obtained from these contour plots were adopted to determine the creatinine concentration in the urine of proteinuria patients. This practical technique can be used for screening and can be further developed as a household biosensing device for urinalysis.

Spectroscopic and color chromaticity analysis of rhodamine 6G dye-doped PVA polymer composites for color tuning applications

Herein we report the successful fabrication of highly flexible, reversibly stretchable and transparent rhodamine 6G/poly(vinyl alcohol) (Rh6G/PVA) polymer composite (PC) films using a user-friendly solution casting method by adding different amounts, viz. 0, 0.5, 1, 1.5 and 2 wt%, of Rh6G dye. The FTIR studies reveal that an interaction between PVA matrix and added Rh6G dye and room-temperature photoluminescence (RTPL) emission intensity is decreased with the increase in the Tg is observed from DSC thermograms. The developed films show appreciable optical and RTPL properties as established by a UV–visible and fluorescence techniques such that the electronic spectral studies substantiate the changes in electronic band structure of PC films, leading to appreciable changes in the optoelectronic properties. These prepared films with excellent optoelectronic properties alongside appreciable flexibilities and stretchabilities aid their applications to organic light emitting diodes (OLED) with enhanced RTPL studies.

Intelligence Driven-Depression Identification of Facebook Users

Depression is a severe dispute in wide-ranging personal health for all. Every year millions of populace endures depression and some few of them receive adequate treatment. Through their Face-book postings and statuses, whatsapp statuses and shares of post, expressive words handling during they speak or post, emotional icons or pictures they post or from their browse histories, expressing user interests, feelings and daily routines can be measured. Many researchers proved that usage of User Generated Content in a proper mode helps to decide one’s depression level. Analyzing the Generated user related contents helps in prediction of depression (Marcus, M., et al., 2012. Depression: A Global Public Health Concern. WHO Dataset, pp.6–8). Leveraging Social media like Facebook, Twitter and Instagram has valuable sign for designating depression in persons. In the proposed work, potential use of Facebook to sense and identify main depressive chaos in individual is explored. Sharing or posting of images or text by an individual plays a vital role in identifying the victim with depression. Text based analysis done on posted or shared textual content, whereas Chromatic analysis done on the images along with text based analysis for the images with textual contents. Emotion features and color features of these two analyses are used to identify the depression level of the individual by psychological classification using Support Vector Machine (SVM). The performance of the SVM is compared with Naïve Bayes Classifier. The Findings and methods of the proposed work, presents a road map in developing new methodologies in identifying the major depression levels of those who suffer and to guide healthcare agencies.

Finding Structure in Time: Visualizing and Analyzing Behavioral Time Series.

The temporal structure of behavior contains a rich source of information about its dynamic organization, origins, and development. Today, advances in sensing and data storage allow researchers to collect multiple dimensions of behavioral data at a fine temporal scale both in and out of the laboratory, leading to the curation of massive multimodal corpora of behavior. However, along with these new opportunities come new challenges. Theories are often underspecified as to the exact nature of these unfolding interactions, and psychologists have limited ready-to-use methods and training for quantifying structures and patterns in behavioral time series. In this paper, we will introduce four techniques to interpret and analyze high-density multi-modal behavior data, namely, to: (1) visualize the raw time series, (2) describe the overall distributional structure of temporal events (Burstiness calculation), (3) characterize the non-linear dynamics over multiple timescales with Chromatic and Anisotropic Cross-Recurrence Quantification Analysis (CRQA), (4) and quantify the directional relations among a set of interdependent multimodal behavioral variables with Granger Causality. Each technique is introduced in a module with conceptual background, sample data drawn from empirical studies and ready-to-use Matlab scripts. The code modules showcase each technique’s application with detailed documentation to allow more advanced users to adapt them to their own datasets. Additionally, to make our modules more accessible to beginner programmers, we provide a “Programming Basics” module that introduces common functions for working with behavioral timeseries data in Matlab. Together, the materials provide a practical introduction to a range of analyses that psychologists can use to discover temporal structure in high-density behavioral data.

Quality assessment of Typhae Pollen Carbonisata based on chromaticity analysis combined with UPLC fingerprinting and thrombin activity.

Typhae pollen (TP) has been used as an anticoagulant in traditional Chinese medicine and throughout Asia. Typhae Pollen Carbonisata (TPC), a processed product of TP, has hemostatic properties. TPC is produced by frying TP, and the degree of processing can be judged by the colour change from yellow to brown. To establish a novel method for quality assessment of TPC and discriminate TPC from underdone products and overdone products. The Commission Internationale de l'Eclairage (CIE) L* a* b* colour space values of TP and TPC were measured to establish the colour model of TPC. Ultra-performance liquid chromatography was developed for fingerprinting. Thrombin activity promoting rates, clotting time, and bleeding time illustrated the difference in the hemostatic effect of the processed products. Chemometric approaches were performed to reveal the correlation between components and colour values or thrombin activity. Reference ranges of colour values and mathematical functions of TPC were established. The developed method was found to be fast, economic, sensitive, and stable. Fingerprints and thrombin activity in conjunction with partial least squares (PLS) demonstrated that peaks 2, 4, 7, 30, and 36 (isorhamnetin) were the main contributors for colour values and hemostatic activity of TPC. TPC and its unqualified products can be effectively distinguished based on chromaticity analysis, which provides a powerful tool for the comprehensive evaluation of the quality of Chinese herbal medicines.

양파껍질 분말의 첨가가 쿠키의 품질 특성, 항산화 활성 및 아크릴아마이드 형성에 미치는 영향

This study was conducted to investigate the quality characteristics, antioxidant activities and levels of acrylamide formation in cookies containing different amounts of onion peel powder. Onion peel powder was incorporated into the cookies at a level of 2–6% based on the total weight of wheat flour. The contents of moisture, ash, crude protein, total polyphenols, total flavonoids, and acrylamide content of cookies were determined, in addition to their antioxidant activities, pH values, loss rates, spread ratios, color, and texture. Upon increasing the amount of onion peel powder, the moisture and ash contents of the cookies increased, wheareas the pH, loss rate and spread ratio of the cookies decreased. In terms of the chromatic analysis, the L and b values decreased, while the a values increased as the amount of added onion peel powder increased. Furthermore, the total polyphenol and total flavonoid contents increased, while the antioxidant activities were significantly higher than that of the control, increasing proportionally with the concentration of onion peel powder. Moreover, the acrylamide contents of the cookies decreased slightly upon increasing the amount of added onion peel powder, with 6% onion peel powder being particularly effective in inhibiting acrylamide formation. These results suggest that the addition of onion peel powder to cookies will increase the value of cookies by enhancing their antioxidant activities and decreasing acrylamide formation.

Non-Destructive and Micro-Invasive Techniques for Characterizing the Ancient Roman Mosaic Fragments

The color characteristics, vibration spectra, phase and mineral composition, internal structural organization of several fragments of the ancient Roman mosaics from the Roman Mosaic Museum, Constanta, Romania were studied by non-destructive (Chromatic analysis, Neutron Diffraction, Neutron Tomography) and micro-invasive techniques (Optical Microscopy, X-ray Diffraction, Field Emission Scanning Electron Microscopy–Energy Dispersive X-ray Spectroscopy, Raman Spectroscopy, Wavelength Dispersion X-ray Fluorescence). These investigations were performed in order to characterize the original Roman mosaic fragments. The major and minor phase components of the studied mosaic fragments were determined, the crystal structure of the main phases was analyzed, and their three-dimension spatial arrangement was reconstructed. The similar composition of the major phases of all mosaic fragments can indicate a generic recipe for making mosaic elements, but minor phases were presumably added for coloring of mosaic pieces. Some degradation areas inside the volume of the mosaic fragments were found by means of neutron diffraction and neutron tomography methods. These degradation areas are probably related to the formation of iron hydroxides during chemical interactions of mosaic fragments with the sea and urban polluted atmosphere.

ХРОМАТИЧЕСКАЯ ИНТЕРПРЕТАЦИЯ ИКОНИЧЕСКИХ КОДОВ В КАРТИНАХ ТАТЬЯНЫ АПРАКСИНОЙ

Авторы осуществили актуальную для «иконического поворота» попытку представить и обосновать лингвистические возможности интерпретации иконического мышления на примере живописных работ Татьяны Апраксиной. Соотношение между сознательными и бессознательными предикатами изобразительного творчества привело к анализу понятия «образ». Показано, что сознательность с необходимостью является выборочной и частичной, тогда как образы бессознания включают множество неосознаваемой информации внешней среды и путем сублимации могут быть материализованы в цветовой среде живописных картин.
 Хроматический анализ цветовой семантики по гендеру (психологическому полу) продемонстрировал существенные отличия для фемининного и маскулинного интеллекта с еще более явной дифференциацией для нормальных и экстремальных условий существования художницы. В творчестве нормативный аспект ее женственности за счет «трансцендентного перехода» в экстремальное состояние оказался менее существенным, чем сублимирующая функция бессознания.
 Это согласовывалось с общепризнанной характеристикой творчества гениальных художников, которым приходится постоянно вынашивать свои образы идеального плана в женственном плане сознания, только после чего и рождаются истинные идеи; поэтому, именно маскулинным женщинам наряду с фемининными мужчинами удавалось достигать запредельных высот истинного творчества.
 Хроматический анализ картин художницы показал гармоничное сочетание предикатов обоих полов в образе, иконика которого изменялась в зависимости от граничных условий так, что проявлялся весь опыт интеллектуального воплощения в переживаниях духа своего времени как предиката и идеала в сублимированном сочетании материи и духа. Высказано предложение, что такое подчинение приоритетов станет способствовать плодотворному развитию живописи.
 Ключевые слова: Татьяна Апраксина, живопись, цвет, образ, иконика, хроматизм, сознание и бессознание.

Intermolecular copigmentation between five common 3-O-monoglucosidic anthocyanins and three phenolics in red wine model solutions: The influence of substituent pattern of anthocyanin B ring

In this study, intermolecular copigmentation between five primary wine monoglucosidic anthocyanins (cyanidin-3-O-glucoside, peonidin-3-O-glucoside, delphinidin-3-O-glucoside, petunidin-3-O-glucoside, and malvidin-3-O-glucoside) and three common wine phenolics (gallic acid, (−)-epicatechin, and quercetin-3-O-glucoside) were investigated through experimental and theoretical methods, and the influence of substituent pattern of anthocyanin B ring was studied emphatically. Chromatic and thermodynamic analysis showed there were great differences among these different pigment-copigment systems. Spatial conformations of the 15 copigmentation complexes were obtained through theoretical calculation, and diverse π-π stacking modes were observed. These results indicated that the substituent pattern of anthocyanin B ring had significant impact on its affinity to copigments, and more, the structures of pigments and copigments determined the color expression and stability of copigmentation together.

Effects of β-cyclodextrin, whey protein, and soy protein on the thermal and storage stability of anthocyanins obtained from purple-fleshed sweet potatoes

The effects of β-cyclodextrin (β-CD), whey protein (WP), and soy protein (SP) on the color loss and degradation of anthocyanins in purple-fleshed sweet potato anthocyanin extracts (PFSPAEs) during thermal treatment and shelf-life storage in model beverage systems by performing chromaticity, degradation kinetics, and principal component analysis. Results showed that WP and SP improved the thermal stability of the PFSPAE, but WP accelerated the color loss of the extract. However, the addition of 25 mg/L SP improved the color and thermal stability of the anthocyanins when heated at 100 °C for 30 min. With regard to the shelf-life storage, the addition of SP and WP showed non-significant effect on the storage stability of the PFSPAE. However, the addition of 2500 mg/L β-CD significantly improved the storage stability of the PFSPAE. In summary, our findings provide useful information on improving the thermal and storage stability of PFSPAEs in beverage systems using food biopolymers.

Chromaticity analysis of diffraction pattern of white light under the grating

From the D65 daylight source, the ten monochromatic lights were evenly selected to be mixed into white light. After grating diffraction, color mixing was performed by using the chromaticity method with the relative intensity as the proportionality factor. The mixed color and its chromaticity parameters at specific diffraction angle positions were obtained to calculate L*, a*, b* and dominant wavelength. The relationship between the parameters of the grating and the chromaticity parameters of the mixed color was studied separately. The results showed that the color of the white light diffraction pattern at the diffraction angle θ = 2° is most significantly affected by d, followed by N. There is well linear correlation between b and L*, a*, b* values; but the effect of b on the color is not obvious. Then the relationship between the light intensity of ten kinds of monochromatic lights and the grating constant according to the grating diffraction intensity equation were drew, and the “rainbow” phenomenon was found. Current method for calculating the average wavelength of mixed colors directly from the “rainbow” graph is verified to be equivalent to the chromaticity method.

Soluble neutral green-colored polymers based on propylenedioxythiophene, benzene and thieno[3,4-b]pyrazine, and their electrochromic properties

Three novel soluble conjugated conducting polymers PBTPT-1, PBTPT-2, and PBTPT-3 were synthesized via Suzuki coupling reaction by employed different feed ratios of the donor units to the acceptor units. 5,7-bis(5-bromo-thiophen-2-yl)-2,3- bis(4-(decyloxy)phenyl)thieno[3,4-b]pyrazine (M2) was prepared and used as the acceptor unit. Besides, benzene (M1) and propylenedioxythiophene (M3) were adopted as the donor units. The molecular structures of the polymers are confirmed by gel permeation chromatography, infrared spectrum, nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS). The optoelectric properties of the polymers were studied by cyclic voltammetry (CV), spectroelectrochemistry, switching kinetics and chromaticity analysis. The thermal stabilities of the polymers were also conducted. Three polymers have narrow band gaps at around 1.50 eV and pseudo-reversible redox activities. For PBTPT-1, the optical contrasts are 24.56 % at 440 nm, 18.96 % at 695 nm and 66.12 % at 1500 nm, and its coloration efficiencies are 196.36 cm2 C−1 at 440 nm, 199.08 cm2 C−1 at 695 nm and 243.49 cm2 C−1 at 1500 nm. Three polymers possessed multichromic property, and exhibited neutral green color with different saturation degrees. Three polymers revealed superior performances in near infrared region to that in visible region, indicating that the copolymers showed prospect applications in the fabrication of near infrared electrochromic device.

Characterization of melanic and non-melanic forms in domestic and peridomestic populations of Triatoma infestans (Hemiptera: Reduviidae)

BackgroundMelanic (dark) morphs have been barely reported in peridomestic and sylvatic conditions for Triatoma infestans, the most important vector of Chagas disease in the Southern Cone of South America. Adults with dark and small yellow markings on the connexivum were collected after manual searches conducted by technical personnel in 62 domiciliary units in Cruz del Eje, Córdoba Province, Argentina. The last community-wide insecticide spraying campaign before the study had been conducted three years earlier. We investigated if there was a measurable color morph variation (melanic and non-melanic) in wings and connexivum; we determined infestation, distribution of melanic and non-melanic forms, and correspondence of colorimetric variation with variations in morphology (wing size and shape and body length), development (wing fluctuating asymmetry), physiology (nutritional status) or behaviour (flight initiation).ResultsForty-nine females, 54 males and 217 nymphs were collected in 24 domiciliary units. House infestation and colonization were 53% and 47%, respectively. Most of the T. infestans individuals (83.2%) were collected in chicken coops; intradomicile infestation was recorded in only one case. The chromatic cluster analysis showed two well-defined groups: melanic and non-melanic. The melanic group included 17 (35%) females and 25 (46%) males. Peridomestic infestation was lower for melanic than for non-melanic adults. Melanic morphs were collected in houses from several localities. Sexual dimorphisms were confirmed by morphometric measurements. Body length was large in melanic adults (P < 0.01 only for males). Differences between groups were significant for wing size and shape, but not for weight or weight/body length ratio. Melanic females and males showed significantly higher fluctuating asymmetry (FA) indices than their non-melanic counterparts.ConclusionsThis is the second report of melanic forms of T. infestans in domestic and peridomestic habitats in the Dry Chaco region of Argentina. Although non-melanic adults exhibited a higher infestation rate, melanic adults were widespread in the area and were collected in the infested domicile and in most types of peridomestic annexes. Differences in morphometric variables between groups might be due to different ecological adaptations. The higher FA levels observed in melanic individuals suggest a higher developmental instability and a selective advantage of non-melanic individuals in domestic and peridomestic habitats.

Heat transfer analysis study for the design of the New Polychromatic Beam Neutron Reflectometer CANDOR (Chromatic Analysis Neutron Diffractometer Or Reflectometer).

A newly developed polychromatic beam neutron reflectometer CANDOR (Chromatic Analysis Neutron Diffractometer Or Reflectometer) on NG-1 at the NIST Center for Neutron research (NCNR) utilizes a wavelength-sensitive neutron detector consisting of 324 analyzing highly-oriented pyrolytic graphite (HOPG) crystals positioned sequentially in rows. Known for having a small thermal diffuse scattering cross section, HOPG crystals can lead to low signal-to-noise ratios in wavelength-sensitive detectors such as CANDOR. Even though it is possible to mathematically separate the desired signal from thermal diffuse scattering; by cooling the detector array of HOPG crystals in order to minimize the Debye Waller effect generates a better solution to this problem. In this heat transfer analysis study we show, within the instrument design constrains and thermodynamic considerations, technical feasibility and test results for the development of the New Polychromatic Beam Neutron Reflectometer CANDOR (Chromatic Analysis Neutron Diffractometer Or Reflectometer) at the NIST Center for Neutron Research.

Progressive impairment of visual function in fibromyalgia

AbstractObjectivesTo evaluate visual fuction affectation in patients with fibromyalgia during 5 years of follow‐up.MethodsOne hundred and eighteen eyes of 118 patients (96.7% women) with fibromyalgia were analysed at a baseline visit and another at 5 years of follow‐up. They underwent visual acuity (VA) measurement with the best correction and with the ETDRS test at 100% and 2.5% of saturation, contrast sensitivity evaluation with Pelli Robson and CSV1000E tests, chromatic vision analysis with the Farnsworth test 15D and Lanthony 15D (using the Color Vision Recorder software), intraocular pressure (IOPmeasurement, visual field with the Easyfield perimeter, stereopsis with TNO test and macular ganglion cell thickness with optica coherence tomography (OCT) of Fourie Domain (Cirrus, Zeiss). All measurements were made by the same observer. In addition, epidemiological and clinical variables such as age at diagnosis, duration of the disease, and quality of life scale (with EQ‐5D test), were recorded.ResultsThe average age at the baseline visit was 52.01 ± 8.81 years with an average duration of fibromyalgia of 7.88 ± 4.25 years, and an average of quality of life EQ‐5D of 45.08 ± 18.84 out of 100. When comparing the baseline visit with the 5‐year visit, no significant differences were found in VA measurements, butsignificant differences were found (p value &lt;0.05) in constrast sensitivity (with Pelli Robson and CSV1000E tests, in A, B, C and D frequencies), in stereopsis, in color vision (with AC CCi indext of the Farnsworth and the Lanthony tests), in visual field (MS and MD indexes). There were no significant differences during the 5 years follow‐up in the ganglion cell layer thickness measured with OCT.ConclusionsThe patients with fibromyalgia present an visual function reduction during the progression of the pathology, but without retinal or ganglion cell layer thinning in OCT.

A comparison between a white LED confocal imaging system and a conventional flash fundus camera using chromaticity analysis

BackgroundConventional flash fundus cameras capture color images that are oversaturated in the red channel and washed out in the green and blue channels, resulting in a retinal picture that often looks flat and reddish. A white LED confocal device was recently introduced to provide a high-quality retinal image with enhanced color fidelity. In this study, we aimed to evaluate the color rendering properties of the white LED confocal system and compare them to those of a conventional flash fundus camera through chromaticity analysis.MethodsA white LED confocal device (Eidon, Centervue, Padova, Italy) and a traditional flash fundus camera (TRC-NW8, Topcon Corporation, Tokyo, Japan) were used to capture fundus images. Color images were evaluated with respect to chromaticity. Analysis was performed according to the image color signature. The color signature of an image was defined as the distribution of its pixels in the rgb chromaticity space. The descriptors used for the analysis are the average and variability of the barycenter positions, the average of the variability and the number of unique colors (NUC) of all signatures.ResultsTwo hundred thirty-three color photographs were acquired with each retinal camera. The images acquired by the confocal white LED device demonstrated an average barycenter position (rgb = [0.448, 0.328, 0.224]) closer to the center of the chromaticity space, while the conventional fundus camera provides images with a clear shift toward red at the expense of the blue and green channels (rgb = [0.574, 0.278, 0.148] (p < 0.001). The variability of the barycenter positions was higher in the white LED confocal system than in the conventional fundus camera. The average variability of the distributions was higher (0.003 ± 0.007, p < 0.001) in the Eidon images compared to the Topcon camera, indicating a greater richness of color. The NUC percentage was higher for the white LED confocal device than for the conventional flash fundus camera (0.071% versus 0.025%, p < 0.001).ConclusionsEidon provides more-balanced color images, with a wider richness of color content, compared to a conventional flash fundus camera. The overall higher chromaticity of Eidon may provide benefits in terms of discriminative power and diagnostic accuracy.

Chromatic pupillometry for the characterization of the pupillary light reflex in Octodon degus

The common degu (Octodon degus) is an emerging model in biomedical science research due to its longevity and propensity to develop human-like conditions. However, there is a lack of standardized techniques for this non-traditional laboratory animal. In an effort to characterize the model, we developed a chromatic pupillometry setup and analysis protocol to characterize the pupillary light reflex (PLR) in our animals. The PLR is a biomarker to detect early signs for central nervous system deterioration. Chromatic pupillometry is a non-invasive and anesthesia-free method that can evaluate different aspects of the PLR, including the response of intrinsically photosensitive retinal ganglion cells (ipRGCs), the disfunction of which has been linked to various disorders. We studied the PLR of 12 degus between 6 and 48 months of age to characterize responses to LEDs of 390, 450, 500, 525 and 605 nm, and used 5 with overall better responses to establish a benchmark for healthy PLR (PLR+) and deteriorated PLR (PLR-). Degu pupils contracted up to 65% of their horizontal resting size before reaching saturation. The highest sensitivity was found at 500 nm, with similar sensitivities at lower tested intensities for 390 nm, coinciding with the medium wavelength and short wavelength cones of the degu. We also tested the post-illumination pupillary response (PIPR), which is driven exclusively by ipRGCs. PIPR was largest in response to 450 nm light, with the pupil preserving 48% of its maximum constriction 9 s after the stimulus, in contrast with 24% preserved in response to 525 nm, response driven mainly by cones. PLR- animals showed maximum constriction between 40% and 50% smaller than PLR+, and their PIPR almost disappeared, pointing to a disfunction of the iPRGCs rather than the retinal photoreceptors. Our method thus allows us to non-invasively estimate the condition of experimental animals before attempting other procedures.

Development of the Stool Color Card for Early Detection of Biliary Atresia using Multispectral Image

The stool color card for early detection of biliary atresia have been developed using multispectral images of stools of newborns. Color and its spectra were measured and analyzed spectrally first in the world and used to design the stool color card. Representative texture was selected by medical specialists from captured multispectral images and spectral information of the images was replaced and edited according to the result of spectral and chromaticity analysis. The stool color card was placed within the Maternal and Child Health Handbook that was distributed to all pregnant women by their respective local government according to the Maternal and Child Health Law in Japan.

Optimization of a magnetostatic cavity for a 3He spin analyzer on the CANDOR polychromatic reflectometer

A new instrument, the CANDOR (Chromatic Analysis Neutron Diffractometer or Reflectometer) polychromatic beam reflectometer is being built at the National Institute of Standards and Technology Center for Neutron Research. CANDOR will have a capability of polarization analysis for both specular and off-specular scattering, and allow for measuring the magnetic structures of magnetic thin films with a significantly shortened measurement time as compared to a conventional monochromatic beam reflectometer at a continuous neutron source. A critical component of the polarization analysis capability is to develop a 3He neutron spin filter (NSF) for polarization analysis for both specular and off-specular scattering for a continuous wavelength range between 4 Å and 6 Å and a large solid angle coverage for up to 20 energy dispersive detector channels. For ex-situ spin-exchange optical pumping (SEOP) operation, a magnetically shielded solenoid (MSS) will be employed to provide a volume averaged field gradient, better than 5×10−4 cm−1 to maintain 3He polarization relaxation times of at least a few hundred hours on the beam line even when there are significant stray fields from a magnet operating at a field up to 3 T at the sample position. We describe a procedure to design, construct, and optimize a MSS with non-identical compensation coil dimensions on the ends to match the scattered neutron beam rays. The volume averaged field gradient is quantified and optimized over a cell for a MSS using the finite-element software package RADIA and compared with that from the experiment.

A Ratiometric Fluorescent Nano-Probe for Rapid and Specific Detection of Tetracycline Residues Based on a Dye-Doped Functionalized Nanoscaled Metal–Organic Framework

Tetracycline (TC) residues are harmful to the environment and human body, so it is necessary to develop a highly sensitive probe for rapid detection of tetracycline residues. In the present paper, a novel dye-doped porous metal–organic framework (UiO-66)-based multi-color fluorescent nano-probe was designed for sensitive ratiometric detection of tetracycline (TC). In this probe, dye-molecules doped UiO-66 was used as a fluorescent internal standard, and the externally grafted lanthanide Eu3+ complex was used as response signals. The fluorescence of the Eu3+ complex was selectively enhanced with increasing concentrations of TC, which was accompanied by a visual blue-to-red color switch. The nano-probe had a linear response between 0.1 and 6 μM with a lowest detection limit of 17.9 nM, which was much lower than the maximum residue limits set by the United States Food and Drug Administration (676 nM) and the European Union (225 nM). The applicability of this method in the analysis of actual samples was evaluated by the determination of TC in honey and milk samples, indicating satisfactory recovery and good reproducibility. In addition, a cost-effective paper-based probe for rapid and visual detection of TC was developed by fixing the nano-probe on filter papers. With the help of a smartphone camera to capture the fluorescence color, and chromaticity analysis software, the calculation and analysis of red (R) and blue (B) values can be realized, which has the potential for real-time visual detection of TC.