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Glucose is an analyte of great importance, both in the clinical and sports fields. Since blood is the gold standard biofluid used for the analytical determination of glucose, there is high interest in finding alternative non-invasive biofluids, such as sweat, for its determination. In this research, we present an alginate-based bead-like biosystem integrated with an enzymatic assay for the determination of glucose in sweat. The system was calibrated and verified in artificial sweat, and a linear calibration range was obtained for glucose of 10–1000 µM. The colorimetric determination was investigated, and the analysis was carried out both in the black and white and in the Red:Green:Blue color code. A limit of detection and quantification of 3.8 µM and 12.7 µM, respectively, were obtained for glucose determination. The biosystem was also applied with real sweat, using a prototype of a microfluidic device platform as a proof of concept. This research demonstrated the potential of alginate hydrogels as scaffolds for the fabrication of biosystems and their possible integration in microfluidic devices. These results are intended to bring awareness of sweat as a complementary tool for standard analytical diagnosis.

Determining the presence of gunshot residue is an important analysis in forensic chemistry. The residue itself is composed of multiple elements and compounds that can be individually detected by various methods. Some of the most common elements found in gunshot residue are metals such as lead, barium, and antimony. In an attempt identify the traces of some of these metals left behind in the residue, laser-induced breakdown spectroscopy (LIBS) and colorimetric analysis using rhodizonic acid will be used for the detection of lead and barium. In these experiments, calibration curves for lead and barium on surfaces by LIBS will be constructed in units of micrograms/cm 2 . In addition, standards of lead and barium will be used to determine the sensitivity of the rhodizonic acid test. Then, gunshot residue will be produced through detonation of shotgun primers near a surface for analysis. A polydimethylsiloxane (PDMS) membrane will be used as a test surface to substitute for skin as it is widely used in the field of analytical chemistry. Then, this surface will be sampled using tape stripping technique. LIBS will be used to identify lead and barium components on the medical adhesive tape that gathers gunshot residue from an artificial skin membrane via the tape-stripping method. Colorimetric analysis will also be used to detect the presence of lead components found in gunshot residue.

Current procedures for the assessment of chronic wound infection are time-consuming and require complex instruments and trained personnel. The incidence of chronic wounds worldwide, and the associated economic burden, urge for simple and cheap point-of-care testing (PoCT) devices for fast on-site diagnosis to enable appropriate early treatment. The enzyme myeloperoxidase (MPO), whose activity in infected wounds is about ten times higher than in non-infected wounds, appears to be a suitable biomarker for wound infection diagnosis. Herein, we develop a single-component foldable paper-based device for the detection of MPO in wound fluids. The analyte detection is achieved in two steps: (i) selective immunocapture of MPO, and (ii) reaction of a specific dye with the captured MPO, yielding a purple color with increasing intensity as a function of the MPO activity in infected wounds in the range of 20–85 U/mL. Ex vivo experiments with wound fluids validated the analytic efficiency of the paper-based device, and the results strongly correlate with a spectrophotometric assay., Peer Reviewed, Postprint (published version)

Lactate is present in sweat at high concentrations, being a metabolite of high interest in sport science and medicine. Therefore, the potential to determine lactate concentrations in physiological fluids, at the point of need with minimal invasiveness, is very valuable. In this work, the synthesis and performance of an alginate bead biosystem was investigated. Artificial sweat with different lactate concentrations was used as a proof of concept. The lactate detection was based on a colorimetric assay and an image analysis method using lactate oxidase, horseradish peroxidase and tetramethyl benzidine as the reaction mix. Lactate in artificial sweat was detected with a R² = 0.9907 in a linear range from 10 mM to 100 mM, with a limit of detection of 6.4 mM and a limit of quantification of 21.2 mM. Real sweat samples were used as a proof of concept to test the performance of the biosystem, obtaining a lactate concentration of 48 ± 3 mM. This novel sensing configuration, using alginate beads, gives a fast and reliable method for lactate sensing, which could be integrated into more complex analytical systems.

Lactate is present in sweat at high concentrations, being a metabolite of high interest in sport science and medicine. Therefore, the potential to determine lactate concentrations in physiological fluids, at the point of need with minimal invasiveness, is very valuable. In this work, the synthesis and performance of an alginate bead biosystem was investigated. Artificial sweat with different lactate concentrations was used as a proof of concept. The lactate detection was based on a colorimetric assay and an image analysis method using lactate oxidase, horseradish peroxidase and tetramethyl benzidine as the reaction mix. Lactate in artificial sweat was detected with a R² = 0.9907 in a linear range from 10 mM to 100 mM, with a limit of detection of 6.4 mM and a limit of quantification of 21.2 mM. Real sweat samples were used as a proof of concept to test the performance of the biosystem, obtaining a lactate concentration of 48 ± 3 mM. This novel sensing configuration, using alginate beads, gives a fast and reliable method for lactate sensing, which could be integrated into more complex analytical systems.

The analysis of the eye fundus is critical to prevent retinal and choroidal diseases since most of them cause no symptoms at early stages. Treating them when the very first signs appear is crucial to avoid vision losses. To this end, the color of eye fundus structures of healthy and diseased patients was assessed from images acquired with a novel multispectral fundus camera (400 nm – 1300 nm) with high spectral and spatial resolution. Characteristic color traits were found: in healthy eyes, large CIEDE2000 color differences were reported between arteries and veins due to different blood oxygenation; the contrast of nerve fibers/fovea was enhanced, giving rise to relevant color differences; in eyes with age related macular degeneration, lesions such as drusen could be better distinguished than with traditional color retinography; alterations of the optic disk in patients with glaucoma were also assessed, showing remarkable CIEDE2000 values when compared to healthy patients, This project has received funding from the European Union's Horizon 2020 research and innovation programme under Marie Skłodowska-Curie grant agreement No. 801342 (Tecniospring INDUSTRY) and the Government of Catalonia's Agency for Business Competitiveness (ACCIÓ). This research was also supported by the Ministerio de Economía, Industria y Competitividad (MINECO), the Agencia Estatal de Investigación (AEI) and the European Regional Development Fund (FEDER) under the grant DPI2017-89414-R., Peer Reviewed, Postprint (published version)

Lactate is present in sweat at high concentrations, being a metabolite of high interest in sport science and medicine. Therefore, the potential to determine lactate concentrations in physiological fluids, at the point of need with minimal invasiveness, is very valuable. In this work, the synthesis and performance of an alginate bead biosystem was investigated. Artificial sweat with different lactate concentrations was used as a proof of concept. The lactate detection was based on a colorimetric assay and an image analysis method using lactate oxidase, horseradish peroxidase and tetramethyl benzidine as the reaction mix. Lactate in artificial sweat was detected with a R² = 0.9907 in a linear range from 10 mM to 100 mM, with a limit of detection of 6.4 mM and a limit of quantification of 21.2 mM. Real sweat samples were used as a proof of concept to test the performance of the biosystem, obtaining a lactate concentration of 48 ± 3 mM. This novel sensing configuration, using alginate beads, gives a fast and reliable method for lactate sensing, which could be integrated into more complex analytical systems.

Nowadays, water quality monitoring is an essential task since environmental contamination and human exposure to heavy metals increased. Sensors that are able to detect ever lower concentrations of heavy metal ions with greater accuracy and speed are needed to effectively monitor water quality and prevent poisoning. This article shows studies of the modification of flexible track-etched membranes as the basis for the sensor with various polymers and their influence on the accuracy of detection of copper, cadmium, and lead ions in water. We report the UV-induced graft (co)polymerization of acrylic acid (AA) and 4-vinylpyridine (4-VPy) on poly(ethylene terephthalate) track-etched membrane (PET TeMs) and use them after platinum layer sputtering in square wave anodic stripping voltammetry (SW-ASV) for detection of Cu2+, Cd2+, and Pb2+. Optimal conditions leading to functionalization of the surface and retention of the pore structure were found. Modified membranes were characterized by SEM, FTIR, X-ray photoelectron spectroscopy (XPS) and colorimetric analysis. The dependence of the modification method on the sensitivity of the sensor was shown. Membrane modified with polyacrylic acid (PET TeMs-g-PAA), poly(4-vinylpyridine) (PET TeMs-g-P4VPy), and their copolymer (PET TeMs-g-P4VPy/PAA) with average grafting yield of 3% have been found to be sensitive to μg/L concentration of copper, lead, and cadmium ions. Limits of detection (LOD) for sensors based on PET TeMs-g-PAA are 2.22, 1.05, and 2.53 μg/L for Cu2+, Pb2+, and Cd2+, respectively. LODs for sensors based on PET TeMs-g-P4VPy are 5.23 μg/L (Cu2+), 1.78 μg/L (Pb2+), and 3.64 μg/L (Cd2+) μg/L. PET TeMs-g-P4VPy/PAA electrodes are found to be sensitive with LODs of 0.74 μg/L(Cu2+), 1.13 μg/L (Pb2+), and 2.07 μg/L(Cd2+). Thus, it was shown that the modification of membranes by copolymers with carboxylic and amino groups leads to more accurate detection of heavy metal ions, associated with the formation of more stable complex

Two commercial waterborne wood acrylic paints were applied to wood samples and the weathering resistance of samples was tested using four different weathering methods: outdoor exposure in Arizona (USA), Florida (USA), and the province of Quebec (Canada), and accelerated weathering in a QUV (fluorescent) weatherometer. Degradation was characterised by colorimetric and FTIR analyses. FTIR confirmed the importance of paint composition in the resistance of samples to weathering. Polymer sensitivity to UV radiation was clearly evident. An interpretation of discoloration in terms of either the energy received by the samples or the length of exposure is presented. Strong differences existed between the four weathering methods. Particularities of each method are discussed and recommendations regarding their application for effective testing are proposed. Overall, in addition to accelerated weathering tests, we conclude that it is necessary to test paints in an end-use environment for accurate assessment of their likely performance. This study confirms the multifactorial aspect of the weathering process

Two commercial waterborne wood acrylic paints were applied to wood samples and the weathering resistance of samples was tested using four different weathering methods: outdoor exposure in Arizona (USA), Florida (USA), and the province of Quebec (Canada), and accelerated weathering in a QUV (fluorescent) weatherometer. Degradation was characterised by colorimetric and FTIR analyses. FTIR confirmed the importance of paint composition in the resistance of samples to weathering. Polymer sensitivity to UV radiation was clearly evident. An interpretation of discoloration in terms of either the energy received by the samples or the length of exposure is presented. Strong differences existed between the four weathering methods. Particularities of each method are discussed and recommendations regarding their application for effective testing are proposed. Overall, in addition to accelerated weathering tests, we conclude that it is necessary to test paints in an end-use environment for accurate assessment of their likely performance. This study confirms the multifactorial aspect of the weathering process.

© 2018 Elsevier B.V. The mining industry produces an earth-derived silicate mineral, called mica, which is included in many cosmetic formulations. Mica minerals produce a shimmering effect on the skin and simultaneously provide physical protection against the harmful effects of the sun. On the other hand, the corn wet-milling industry produces an effluent that contains a natural extract with antioxidant and biosurfactant properties, which could possibly be used to increase the protective effect of mica minerals against ultraviolet light (UV light). In this study, we determined the sunscreen protection factor (SPF) of different biocomposites based on different mica minerals alone or mixed with a biosurfactant extract obtained from the corn industry. The SPF values of water-based formulations containing mica with and without the biosurfactant extract were determined by means of a standardized method in which the absorbance was determined at wavelengths between 290 and 320 nm. The SPF values obtained for the mica minerals in the absence of biosurfactant ranged between 0.2 and 11, and in some cases the addition of biosurfactant increased the SPF values of the micas by more than 2000%., Peer Reviewed, Postprint (author's final draft)

We report a microfluidic sample preparation platform called "Slipdisc" based on slipchip technology. Slipdisc is a rotational slipchip that uses a unique hand-wound clockwork mechanism for precise movement of specially fabricated polycarbonate discs. In operation, the microchannels and microchambers carved on the closely aligned microfluidic discs convert from continuous filled paths to defined compartments using the slip movement. The clockwork mechanism introduced here is characterised by a food dye experiment and a conventional HRP TMB reaction before measuring lactate dehydrogenase (LDH) enzyme levels, which is a crucial biomarker for neonatal diagnostics. The colorimetry based detection of LDH was performed with an unmodified camera and an image analysis procedure based on normalising images and observing changes in red channel intensity. The analysis showed a close to unity coefficient of determination (R2 = 0.96) in detecting the LDH concentration when compared with a standard Chemical Analyser, demonstrating the excellent performance of the slipdisc platform with colorimetric detection. The versatile point of care sample preparation platform should ideally be suited for a multitude of applications at resource-limited settings., QC 20171201

Our purpose was to improve the thermal, mechanical and optimal properties of an epoxy bioresin using optimum hybrid natural pigments previously synthesised in our lab. Next, we searched for the best combinations of factors in the synthesis of natural hybrid nanopigments and then incorporated them into the bioresin. We combined three structural modifiers in the nanopigment synthesis, surfactant, coupling agent (silane) and a mordant salt (alum), selected to replicate mordant textile dyeing with natural dyes. We used Taguchi s design L8 to seek final performance optimisation. We selected three natural dyes, chlorophyll, beta-carotene and beetroot extract, and used two laminar nanoclay types, montmorillonite and hydrotalcite. The thermal, mechanical and colorimetric characterisation of the composite obtained by mixing natural hybrid nanopigments (bionanocomposite) was made. The natural dye interactions with both nanoclays improved the thermal stabilities, colour performance and UV VIS light exposure stability of natural dyes and bioresins. The best bionanocomposite materials were found in an acidic pH [3, 4] environment and by modifying nanoclays with mordant and surfactant during the nanopigment synthesis process

Our purpose was to improve the thermal, mechanical and optimal properties of an epoxy bioresin using optimum hybrid natural pigments previously synthesised in our lab. Next, we searched for the best combinations of factors in the synthesis of natural hybrid nanopigments and then incorporated them into the bioresin. We combined three structural modifiers in the nanopigment synthesis, surfactant, coupling agent (silane) and a mordant salt (alum), selected to replicate mordant textile dyeing with natural dyes. We used Taguchi s design L8 to seek final performance optimisation. We selected three natural dyes, chlorophyll, beta-carotene and beetroot extract, and used two laminar nanoclay types, montmorillonite and hydrotalcite. The thermal, mechanical and colorimetric characterisation of the composite obtained by mixing natural hybrid nanopigments (bionanocomposite) was made. The natural dye interactions with both nanoclays improved the thermal stabilities, colour performance and UV VIS light exposure stability of natural dyes and bioresins. The best bionanocomposite materials were found in an acidic pH [3, 4] environment and by modifying nanoclays with mordant and surfactant during the nanopigment synthesis process

The fabrication of microfluidic chips can be simplified and accelerated by three-dimensional (3D) printing. However, all of the current designs of 3D printed microchips require off-chip bulky equipment to operate, which hindered their applications in the point-of-care (POC) setting. In this work, we demonstrate a new class of movable 3D printed microfluidic chip components, including torque-actuated pump and valve, rotary valve, and pushing valve, which can be operated manually without any off-chip bulky equipment such as syringe pump and gas pressure source. By integrating these components, we developed a user-friendly 3D printed chip that can perform general colorimetric assays. Protein quantification was performed on artificial urine samples as a proof-of-concept model with a smartphone used as the imaging platform. The protein was quantified linearly and was within the physiologically relevant range for humans. We believe that the demonstrated components and designs can expand the functionalities and potential applications of 3D printed microfluidic chip and thus provoke more investigation on manufacturing lab-on-a-chip devices by 3D printers.

The fabrication of microfluidic chips can be simplified and accelerated by three-dimensional (3D) printing. However, all of the current designs of 3D printed microchips require off-chip bulky equipment to operate, which hindered their applications in the point-of-care (POC) setting. In this work, we demonstrate a new class of movable 3D printed microfluidic chip components, including torque-actuated pump and valve, rotary valve, and pushing valve, which can be operated manually without any off-chip bulky equipment such as syringe pump and gas pressure source. By integrating these components, we developed a user-friendly 3D printed chip that can perform general colorimetric assays. Protein quantification was performed on artificial urine samples as a proof-of-concept model with a smartphone used as the imaging platform. The protein was quantified linearly and was within the physiologically relevant range for humans. We believe that the demonstrated components and designs can expand the functionalities and potential applications of 3D printed microfluidic chip and thus provoke more investigation on manufacturing lab-on-a-chip devices by 3D printers.

The fabrication of microfluidic chips can be simplified and accelerated by three-dimensional (3D) printing. However, all of the current designs of 3D printed microchips require off-chip bulky equipment to operate, which hindered their applications in the point-of-care (POC) setting. In this work, we demonstrate a new class of movable 3D printed microfluidic chip components, including torque-actuated pump and valve, rotary valve, and pushing valve, which can be operated manually without any off-chip bulky equipment such as syringe pump and gas pressure source. By integrating these components, we developed a user-friendly 3D printed chip that can perform general colorimetric assays. Protein quantification was performed on artificial urine samples as a proof-of-concept model with a smartphone used as the imaging platform. The protein was quantified linearly and was within the physiologically relevant range for humans. We believe that the demonstrated components and designs can expand the functionalities and potential applications of 3D printed microfluidic chip and thus provoke more investigation on manufacturing lab-on-a-chip devices by 3D printers.

In the current study, the quantification of different model proteins in the presence of typical aqueous two-phase system components was investigated by using the Bradford and bicinchoninic acid (BCA) assays. Each phase-forming component above 1 and 5 wt% had considerable effects on the protein quantification in both assays, respectively, resulting in diminished protein recoveries/absorption values by increasing poly(ethylene glycol) (PEG)/salt concentration and PEG molecular weight. Therefore, a convenient dilution of both components (up to 1 and 5 wt%) before protein quantification is recommended in both assays, respectively, where the BCA assay is favored in comparison with the Bradford assay.

Oxygen plays an important role in wound healing, as it is essential to biological functions such as cell proliferation, immune responses and collagen synthesis. Poor oxygenation is directly associated with the development of chronic ischemic wounds, which affect more than 6 million people each year in the United States alone at an estimated cost of $25 billion. Knowledge of oxygenation status is also important in the management of burns and skin grafts, as well as in a wide range of skin conditions. Despite the importance of the clinical determination of tissue oxygenation, there is a lack of rapid, user-friendly and quantitative diagnostic tools that allow for non-disruptive, continuous monitoring of oxygen content across large areas of skin and wounds to guide care and therapeutic decisions. In this work, we describe a sensitive, colorimetric, oxygen-sensing paint-on bandage for two-dimensional mapping of tissue oxygenation in skin, burns, and skin grafts. By embedding both an oxygensensing porphyrin-dendrimer phosphor and a reference dye in a liquid bandage matrix, we have created a liquid bandage that can be painted onto the skin surface and dries into a thin film that adheres tightly to the skin or wound topology. When captured by a camera-based imaging device, the oxygen-dependent phosphorescence emission of the bandage can be used to quantify and map both the pO2 and oxygen consumption of the underlying tissue. In this proof-of-principle study, we first demonstrate our system on a rat ischemic limb model to show its capabilities in sensing tissue ischemia. It is then tested on both ex vivo and in vivo porcine burn models to monitor the progression of burn injuries. Lastly, the bandage is applied to an in vivo porcine graft model for monitoring the integration of full- and partial thickness skin grafts., Published in Biomedical Optics Express, v5 n11 p3748-3764, 1 Oct 2014.

Monitoring aspects of human performance during various activities has recently become a highly investigated research area. Many new commercial products are available now to monitor human physical activity or responses while performing activities ranging from playing sports, to driving, and even sleeping. However, monitoring cognitive performance biomarkers, such as neuropeptides, is still an emerging field due to the complicated sample collection and processing, as well as the need for a clinical lab to perform analysis. Enzyme-linked immunosorbent assays (ELISAs) provide specific detection of biomolecules with high sensitivity (pM concentrations). Even with the advantage of high sensitivity, most ELISAs need to be performed in a laboratory setting and require around six hours to complete. Transitioning this assay to a platform where it reduces cost, shortens assay time, and is able to be performed outside a lab is invaluable. Recently developed paper diagnostics provide an inexpensive platform to perform ELISAs on; however, the major limiting factor for moving out of the laboratory environment is the measurement and analysis instrumentation. Using something as simple as a digital camera or camera-enabled Windows- or Android-based tablets, we are able to image a paper-based ELISAs (P-ELISAs), perform image analysis, and produce response curves with high correlation to target biomolecule concentration in the 10 pM range. Neuropeptide Y detection was performed Additionally, silver enhancement of Au NPs conjugated with IgG antibodies showed concentration dependent response to IgG; thus, eliminating the need for an enzyme-substrate system. Automated image analysis and quantification of antigen concentrations are able to be performed on Windows- and Android-based mobile platforms., To be published in Analytical Chemistry.

Colourimetric sensors and indicators are widely used because of their low cost and simplicity. A significant challenge associated with the design of this type of device is that the sensing mechanism must be simultaneously optimised for the sensitivity of the response and a visually perceptible colour change. Structural colour, derived from coherent scattering rather than molecular absorption, is a promising route to colourimetric sensor design because colour shifts are tied to changes in one of many physical properties of a material, rather than a specific chemical process. This Feature Article presents an overview of the development of low-cost sensors and indicators that exploit structural colour. Building upon recent advances in structurally adaptive materials design, structural colour sensors have been developed for a wide variety of previously inaccessible physical (e.g. temperature, strain, electric fields) and chemical stimuli (e.g. small organic molecules, charged species, biomacromolecules and metabolites). These devices, often exceeding the state of the art in performance, simplicity or both, have bright prospects for market impact in areas such as environmental monitoring, workplace hazard identification, threat detection, and point-of-care diagnostics. Finding the ideal balance between performance (e.g. sensitivity, specificity, reproducibility, etc.) and simplicity (e.g. colourimetric vs. spectroscopic readout) will be one of the most critical elements in the further development of structural colour sensors. This balance should be driven largely by the market demands and competing technologies., Published in Journal of Materials Chemistry C, 2013.

During this project the Boston University team developed novel approaches to enhance light-matter coupling in optical devices by engineering photonic-plasmonic resonances in aperiodically ordered nanostructures. In particular, they designed, fabricated and characterized a large number of active photonic nanomaterials and structures and demonstrated unique optical properties such as broadband enhanced local field intensity, scattering, radiative (i.e., light emission) and nonlinear responses (i.e., second harmonic generation, nonlinear refractive index) using Si compatible materials and processing. Fabricated metal-dielectric devices have been integrated with planar Si chips for applications of aperiodic order to light emission, optical sensing, on-chip nonlinear generation, solar energy conversion, and singular optics. The fabrication and experimental characterization of materials and device demonstrators have been partnered with the development of efficient computational design tools based on semi-analytical multiple scattering theory, which allowed the rigorous study and optimization of large-scale aperiodic media for the first time., The original document contains color images.

A portable, wireless system capable of in-situ reagent-based colorimetric analysis is demonstrated. The system is based on a reconfigurable low cost optical detection method employing a paired emitter detector diode device, which allows a wide range of centrifugal microfluidic layouts to be implemented. Due to the wireless communication, acquisition parameters can be controlled remotely and results can be downloaded in distant locations and displayed in real time. The stand-alone capabilities of the system, combined with the portability and wireless communication, provide the flexibility crucial for on-site water monitoring. The centrifugal microfluidic disc presented here is designed for nitrite detection in water samples, as a proof of principle. A limit of detection of 9.31 ppb, along with similar coefficient of correlation and precision, were obtained from the Centrifugal Microfluidic Analysis System compared with the same parameters measured using a UV-Vis spectrophotometer.

A portable, wireless system capable of in-situ reagent-based colorimetric analysis is demonstrated. The system is based on a reconfigurable low cost optical detection method employing a paired emitter detector diode device, which allows a wide range of centrifugal microfluidic layouts to be implemented. Due to the wireless communication, acquisition parameters can be controlled remotely and results can be downloaded in distant locations and displayed in real time. The stand-alone capabilities of the system, combined with the portability and wireless communication, provide the flexibility crucial for on-site water monitoring. The centrifugal microfluidic disc presented here is designed for nitrite detection in water samples, as a proof of principle. A limit of detection of 9.31 ppb, along with similar coefficient of correlation and precision, were obtained from the Centrifugal Microfluidic Analysis System compared with the same parameters measured using a UV-Vis spectrophotometer.

Brazil is known for its sugar cane production. Raw sugar is produced by artisanal farmers. As a result of artisanal production, raw sugar is diverse in color. The aim of this study was to analyze raw sugar color and its sensory acceptance in the market of Viçosa, Minas Gerais, Brazil. Colorimetric tests (CIELAB) were done. The results were analyzed by multivariate analysis, similarity and dissimilarity measurements and clustering techniques (GENES software). Two samples of raw sugar commercialized by Associação Riobranquense de Produtores de Rapadura, Áçucar Mascavo, Aguardente e Melado (ARPRAM), eleven samples produced of his associates and six samples from commercial brands were colorimetrically analyzed. Three representative samples of dark, semi-dark and light color were chosen to test color sensory acceptance. This assessment used a nine point hedonic scale. Of the 19 samples analyzed, 13 had visible color differences. Samples with the highest dissimilarity were from a producer and from ARPRAM, with 16.47 Euclidean distance. Samples with greatest similarity were from ARPRAM and from a commercial brand with 0.44 Euclidean distance. There was no significant difference in color sensory acceptance among the tested raw sugar samples. Colorimetric analysis confirmed a lack of color uniformity among the samples produced and marketed by ARPRAM and from the commercial brand. However, differences in color did not influence the sensory acceptance of raw sugar among consumers., O Brasil destaca-se pela sua produção de cana-de-açúcar. O açúcar mascavo é um nutritivo e saudável subproduto, obtido artesanalmente por agricultores familiares. Entretanto, como resultado de sua produção artesanal, o açúcar mascavo apresenta diversidade na cor. O objetivo deste estudo foi analisar a cor do açúcar mascavo e sua aceitação no mercado de Viçosa, Minas Gerais. Foram realizadas análises colorimétricas (CIELAB) e os resultados avaliados mediante análise multivariada, medidas de dissimilaridade e similaridade, e técnicas de agrupamento (programa GENES). Para a análise colorimétrica foram avaliadas duas amostras de açúcar mascavo comercializadas pela Associação Riobranquense de Produtores de Rapadura, Açúcar Mascavo, Aguardente e Melado (ARPRAM), onze obtidas de seus associados e seis amostras de marcas comerciais. Para teste de aceitação da cor pelos consumidores foram escolhidas três amostras representativas das cores: escura, semi-escura e clara. Para esta avaliação foi usada uma escala hedônica de nove pontos. Das 19 amostras analisadas, 13 apresentaram diferenças de cor visível. As amostras com maior dissimilaridade foram as de um produtor e da ARPRAM, apresentando distância euclidiana média de 16,47. As amostras com maior similaridade foram obtidas de um associado da ARPRAM e de uma marca comercial com distância de 0,44. Não houve diferença significativa no teste de aceitação de cor das amostras de açúcar mascavo. Com a análise colorimétrica foi comprovado que não há uniformidade da cor entre as amostras produzidas e comercializadas pela ARPRAM, bem como as obtidas comercialmente. Entretanto, para o consumidor as diferenças na cor não influenciam na aceitação do açúcar mascavo., Brasil es destacado por su producción en caña de azúcar. El azúcar mascavo es un nutritivo y saludable subproducto obtenido artesanalmente por agricultores familiares, lo que hace que presente variedad en su color. El objetivo del presente estudio fue analizar el color del azúcar mascavo y su aceptación en el mercado de Viçosa, Minas Gerais. Se realizó análisis colorimétrico (CIELAB) y los resultados fueron evaluados mediante análisis multivariada, medidas de disimilaridad y similaridad, y técnicas de agrupamiento (programa GENES). Para el análisis colorimétrico se evaluaron dos muestras de azúcar mascavo comercializadas por la Asociación Riobranquense de Productores de Panela, Azúcar Mascavo, Aguardiente y Melado (ARPRAM), once obtenidas de sus asociados y seis muestras de marcas comerciales. Para la prueba de aceptación del color por parte de los consumidores se seleccionaron tres muestras representativas de los colores: oscura, semi-oscura y clara, evaluadas mediante escala hedónica de nueve puntos. De las 19 muestras analizadas, 13 presentaron diferencias de color visible. Las muestras con mayor disimilaridad fueron las de un productor y una de las comercializadas por ARPRAM, presentando distancia euclidiana media de 16,47. Las muestras con mayor similaridad fueron las de un productor y la de una marca comercial con distancia de 0,44. No hubo diferencia significativa en la prueba de aceptación del color de las muestras de azúcar mascavo. Con el análisis colorimétrico se comprobó que no hay uniformidad en el color entre las muestras producidas y comercializadas por la ARPRAM y las de marcas comerciales. Por otra parte, para el consumidor las diferencias en el color no influyen en la aceptación del azúcar mascavo.

Brazil is known for its sugar cane production. Raw sugar is produced by artisanal farmers. As a result of artisanal production, raw sugar is diverse in color. The aim of this study was to analyze raw sugar color and its sensory acceptance in the market of Viçosa, Minas Gerais, Brazil. Colorimetric tests (CIELAB) were done. The results were analyzed by multivariate analysis, similarity and dissimilarity measurements and clustering techniques (GENES software). Two samples of raw sugar commercialized by Associação Riobranquense de Produtores de Rapadura, Áçucar Mascavo, Aguardente e Melado (ARPRAM), eleven samples produced of his associates and six samples from commercial brands were colorimetrically analyzed. Three representative samples of dark, semi-dark and light color were chosen to test color sensory acceptance. This assessment used a nine point hedonic scale. Of the 19 samples analyzed, 13 had visible color differences. Samples with the highest dissimilarity were from a producer and from ARPRAM, with 16.47 Euclidean distance. Samples with greatest similarity were from ARPRAM and from a commercial brand with 0.44 Euclidean distance. There was no significant difference in color sensory acceptance among the tested raw sugar samples. Colorimetric analysis confirmed a lack of color uniformity among the samples produced and marketed by ARPRAM and from the commercial brand. However, differences in color did not influence the sensory acceptance of raw sugar among consumers., O Brasil destaca-se pela sua produção de cana-de-açúcar. O açúcar mascavo é um nutritivo e saudável subproduto, obtido artesanalmente por agricultores familiares. Entretanto, como resultado de sua produção artesanal, o açúcar mascavo apresenta diversidade na cor. O objetivo deste estudo foi analisar a cor do açúcar mascavo e sua aceitação no mercado de Viçosa, Minas Gerais. Foram realizadas análises colorimétricas (CIELAB) e os resultados avaliados mediante análise multivariada, medidas de dissimilaridade e similaridade, e técnicas de agrupamento (programa GENES). Para a análise colorimétrica foram avaliadas duas amostras de açúcar mascavo comercializadas pela Associação Riobranquense de Produtores de Rapadura, Açúcar Mascavo, Aguardente e Melado (ARPRAM), onze obtidas de seus associados e seis amostras de marcas comerciais. Para teste de aceitação da cor pelos consumidores foram escolhidas três amostras representativas das cores: escura, semi-escura e clara. Para esta avaliação foi usada uma escala hedônica de nove pontos. Das 19 amostras analisadas, 13 apresentaram diferenças de cor visível. As amostras com maior dissimilaridade foram as de um produtor e da ARPRAM, apresentando distância euclidiana média de 16,47. As amostras com maior similaridade foram obtidas de um associado da ARPRAM e de uma marca comercial com distância de 0,44. Não houve diferença significativa no teste de aceitação de cor das amostras de açúcar mascavo. Com a análise colorimétrica foi comprovado que não há uniformidade da cor entre as amostras produzidas e comercializadas pela ARPRAM, bem como as obtidas comercialmente. Entretanto, para o consumidor as diferenças na cor não influenciam na aceitação do açúcar mascavo., Brasil es destacado por su producción en caña de azúcar. El azúcar mascavo es un nutritivo y saludable subproducto obtenido artesanalmente por agricultores familiares, lo que hace que presente variedad en su color. El objetivo del presente estudio fue analizar el color del azúcar mascavo y su aceptación en el mercado de Viçosa, Minas Gerais. Se realizó análisis colorimétrico (CIELAB) y los resultados fueron evaluados mediante análisis multivariada, medidas de disimilaridad y similaridad, y técnicas de agrupamiento (programa GENES). Para el análisis colorimétrico se evaluaron dos muestras de azúcar mascavo comercializadas por la Asociación Riobranquense de Productores de Panela, Azúcar Mascavo, Aguardiente y Melado (ARPRAM), once obtenidas de sus asociados y seis muestras de marcas comerciales. Para la prueba de aceptación del color por parte de los consumidores se seleccionaron tres muestras representativas de los colores: oscura, semi-oscura y clara, evaluadas mediante escala hedónica de nueve puntos. De las 19 muestras analizadas, 13 presentaron diferencias de color visible. Las muestras con mayor disimilaridad fueron las de un productor y una de las comercializadas por ARPRAM, presentando distancia euclidiana media de 16,47. Las muestras con mayor similaridad fueron las de un productor y la de una marca comercial con distancia de 0,44. No hubo diferencia significativa en la prueba de aceptación del color de las muestras de azúcar mascavo. Con el análisis colorimétrico se comprobó que no hay uniformidad en el color entre las muestras producidas y comercializadas por la ARPRAM y las de marcas comerciales. Por otra parte, para el consumidor las diferencias en el color no influyen en la aceptación del azúcar mascavo.

The aim of this study was to investigate the effect of different carotenoid sources on goldfish (Carassius auratus) skin pigmentation. The value of goldfish depends on the intensity of the skin color. In the red variety of goldfish, an orange-red hue is desirable. Juvenile goldfish were fed one of five diets for five months to determine the effects of carotenoids on skin pigmentation, growth, feed efficiency, and survival: (1) astaxanthin (carophyll pink at 75 mg/kg), (2) canthaxanthin (carophyll red at 75 mg/kg), (3) Gammarus spp. (75 mg/kg), (4) Oleoresin paprika (180 mg/kg), and (5) an unsupplemented control. Growth and feed efficiency did not significantly differ among groups. Initial and final samples of head skin were measured by colorimetric analysis for lightness (L*), redness (a*), yellowness (b*), hue (Hºab), and chroma (Cab*). The best red color (a* and Hºab) was obtained with the astaxanthin, canthaxanthin, and paprika diets.

The aim of this study was to investigate the effect of different carotenoid sources on goldfish (Carassius auratus) skin pigmentation. The value of goldfish depends on the intensity of the skin color. In the red variety of goldfish, an orange-red hue is desirable. Juvenile goldfish were fed one of five diets for five months to determine the effects of carotenoids on skin pigmentation, growth, feed efficiency, and survival: (1) astaxanthin (carophyll pink at 75 mg/kg), (2) canthaxanthin (carophyll red at 75 mg/kg), (3) Gammarus spp. (75 mg/kg), (4) Oleoresin paprika (180 mg/kg), and (5) an unsupplemented control. Growth and feed efficiency did not significantly differ among groups. Initial and final samples of head skin were measured by colorimetric analysis for lightness (L*), redness (a*), yellowness (b*), hue (Hºab), and chroma (Cab*). The best red color (a* and Hºab) was obtained with the astaxanthin, canthaxanthin, and paprika diets.

A quantitative analytical imaging approach for determining the nickel content of metallic meteorites is proposed. The approach uses a digital image of a series of standard solutions of the nickel-dimethylglyoxime coloured chelate and a meteorite sample solution subjected to the same treatment as the nickel standards for quantitation. The image is processed with suitable software to assign a colour-dependent numerical value (analytical signal) to each standard. Such a value is directly proportional to the analyte concentration, which facilitates construction of a calibration graph where the value for the unknown sample can be interpolated to calculate the nickel content of the meteorite. The results thus obtained were validated by comparison with the official, ISO-endorsed spectrophotometric method for nickel. The proposed method is fairly simple and inexpensive; in fact, it uses a commercially available digital camera as measuring instrument and the images it provides are processed with highly user-friendly public domain software (specifically, ImageJ, developed by the National Institutes of Health and freely available for download on the Internet). In a scenario dominated by increasingly sophisticated and expensive equipment, the proposed method provides a cost-effective alternative based on simple, robust hardware that is affordable and can be readily accessed worldwide. This can be especially advantageous for countries were available resources for analytical equipment investments are scant. The proposed method is essentially an adaptation of classical chemical analysis to current, straightforward, robust, cost-effective instrumentation. © 2010 Elsevier B.V. All rights reserved.

The aim of this study was to investigate the effect of different carotenoid sources on goldfish (Carassius auratus) skin pigmentation. The value of goldfish depends on the intensity of the skin color. In the red variety of goldfish, an orange-red hue is desirable. Juvenile goldfish were fed one of five diets for five months to determine the effects of carotenoids on skin pigmentation, growth, feed efficiency, and survival: (1) astaxanthin (carophyll pink at 75 mg/kg), (2) canthaxanthin (carophyll red at 75 mg/kg), (3) Gammarus spp. (75 mg/kg), (4) Oleoresin paprika (180 mg/kg), and (5) an unsupplemented control. Growth and feed efficiency did not significantly differ among groups. Initial and final samples of head skin were measured by colorimetric analysis for lightness (L*), redness (a*), yellowness (b*), hue (Hºab), and chroma (Cab*). The best red color (a* and Hºab) was obtained with the astaxanthin, canthaxanthin, and paprika diets.

A detection system for theophylline that combined the recognition properties of an aptamer and that plasmonic response of gold nanoparticles (AuNPs) is presented. The aptamer was used as a linker for AuNPs functionalized with complementary sequences to the aptamer (DNA-AuNPs), producing supramolecular complexes that disassemble when exposed to theophylline due to aptamer binding. The detection event was reported as a change in the AuNPs plasmonic peak and intensity. Addition of a spacer on the DNA immobilized on the AuNPs facing the aptamer binding site improved the aggregates' response, doubling the detection range of system response to theophylline. Modification of the oligonucleotides immobilized on the AuNPs that reduced the interparticle distance in the aggregated state suppressed their response to theophylline and addition of the spacer recovered it. This work demonstrated that the design of oligonucleotides immobilized on the AuNPs could be used to improve their plasmonic response without affecting aptamer performance., Published in Biosensors & Bioelectronics, v26 n1 p23-28, 16 Sep 2010; available online 7 May 2010. The original document contains color images. All DTIC reproductions will be in black and white.

Across many environments, nitrate ( $\mbox{NO}_{3}^-$ ) is an important form of N available for microorganisms and photosynthetic organisms. Accurate $\mbox{NO}_{3}^-$ measurements are important for examining N cycling and retention in terrestrial and aquatic ecosystems, but a common method of $\mbox{NO}_{3}^-$ analysis can underestimate $\mbox{NO}_{3}^-$ concentrations when soluble iron is present (iron > 10 mg L − 1). The basic method is robust, using copperized cadmium to reduce $\mbox{NO}_{3}^-$ and then diazotizing the resulting $\mbox{NO}_{2}^-$ in a two-step process to form an easily measured colored product. We show that iron interference is unique to using an NH4Cl and ethylenediaminetetraacetic acid (EDTA) buffer. We hypothesize that interference is through iron-catalyzed reduction of the intermediate color product, a diazonium ion. We examine three historical buffers as alternatives to NH4Cl/EDTA and recommend replacement of EDTA with diethylenetriaminepentaacetic acid, which chelates metals much like EDTA, but unlike EDTA, it does not cause interference in the presence of iron.

Across many environments, nitrate ( $\mbox{NO}_{3}^-$ ) is an important form of N available for microorganisms and photosynthetic organisms. Accurate $\mbox{NO}_{3}^-$ measurements are important for examining N cycling and retention in terrestrial and aquatic ecosystems, but a common method of $\mbox{NO}_{3}^-$ analysis can underestimate $\mbox{NO}_{3}^-$ concentrations when soluble iron is present (iron > 10 mg L − 1). The basic method is robust, using copperized cadmium to reduce $\mbox{NO}_{3}^-$ and then diazotizing the resulting $\mbox{NO}_{2}^-$ in a two-step process to form an easily measured colored product. We show that iron interference is unique to using an NH4Cl and ethylenediaminetetraacetic acid (EDTA) buffer. We hypothesize that interference is through iron-catalyzed reduction of the intermediate color product, a diazonium ion. We examine three historical buffers as alternatives to NH4Cl/EDTA and recommend replacement of EDTA with diethylenetriaminepentaacetic acid, which chelates metals much like EDTA, but unlike EDTA, it does not cause interference in the presence of iron.

La consolidación textil se encuentra entre los procedimientos de mayor compromiso técnico y ético en la intervención de tejidos históricos. Dicho tratamiento plantea siempre cuestiones acerca de la reversibilidad de materiales y métodos especialmente en aquellos casos en los que la extrema degradación del tejido requiere la aplicación de una sustancia adhesiva que refuerce las fibras y restablezca su consistencia desde su interior. Sin embargo, los sistemas mediante costura ofrecen una alternativa válida y eficiente en el caso de piezas levemente degradadas que apenas necesitan un refuerzo mínimo adicional. Así mismo, la aplicación de piezas de refuerzo mediante costura es igualmente útil en el caso de los tratamientos de reposición de faltantes del tejido original, donde se evidencia la necesidad de asemejar tanto las características textiles como su naturaleza química, color, etc. entre añadidos y original. Durante años ha venido siendo habitual el empleo de sustancias naturales tintóreas en el teñido de textiles, tal es el caso del café. El presente trabajo pretende ser una primera aproximación al uso del café como sustancia tintórea y a su vez establecer su efectividad en la tinción de tejidos de seda utilizados como piezas de refuerzo en los tratamientos de consolidación textil. Para ello, se ha optimizado el proceso de tinción con este colorante natural usando distintas recetas procedentes de tratados especializados (tanto en lo referente a métodos de tinción directa y con pretratamiento con agentes mordientes como alumbre,m dicromato potásico o sulfato de cobre). Posteriormente, se han evaluado los efectos de las distintas variantes de los procesos de tinción mediante análisis colorimétrico, microscopia óptica y microscopia electrónica (SEM/EDX). Los resultados obtenidos establecen que se ha alcanzado una óptima gama de tonalidades muy similares a los tejidos de seda históricos, con lo que podrían ser utilizados en los tratamientos de consolidación textil., Textile consolidation is one of the most technically and ethically awkward procedures in the intervention on ancient fabrics. This treatment always brings up issues about the reversibility of materials and methods, particularly in cases in which the extreme degradation of the fabric requires the application of an adhesive substance to reinforce the fibres and re-establish their consistency from the inside. Sewing systems nevertheless constitute a valid and efficient alternative in the case of slightly deteriorated items that barely need any further minimum reinforcement. Hence, the application of reinforcement pieces by sewing these on is similarly useful in the case of treatments for replacement of missing pieces of the original fabric, where one can see a need for likening both the textile characteristics and their chemical nature, colour, etc. of the items added and the original. The use of natural substances for dyeing fabrics, as is the case of coffee, has been a common practice for years. This work sets out to be a first approach to the use of coffee as a dye and in turn to establish its effectiveness in dyeing silk fabrics used as reinforcement items in textile consolidation processes. This was done by optimising the dyeing process with this natural colorant, using different recipes from specialised treatises (both as regards direct dyeing methods and those applying a pre-treatment with mordant agents such as alum, potassium dichromate or copper sulphate). Later on, the effects of the different variants in the dyeing processes were assessed by means of colorimetric analysis, optical microscopy and electronic microscopy (SEM/EDX). The results obtained establish that an optimum range of tones very similar to historic silk fabrics has been attained, thus meaning that these can be used in textile consolidation treatments.

La consolidación textil se encuentra entre los procedimientos de mayor compromiso técnico y ético en la intervención de tejidos históricos. Dicho tratamiento plantea siempre cuestiones acerca de la reversibilidad de materiales y métodos especialmente en aquellos casos en los que la extrema degradación del tejido requiere la aplicación de una sustancia adhesiva que refuerce las fibras y restablezca su consistencia desde su interior. Sin embargo, los sistemas mediante costura ofrecen una alternativa válida y eficiente en el caso de piezas levemente degradadas que apenas necesitan un refuerzo mínimo adicional. Así mismo, la aplicación de piezas de refuerzo mediante costura es igualmente útil en el caso de los tratamientos de reposición de faltantes del tejido original, donde se evidencia la necesidad de asemejar tanto las características textiles como su naturaleza química, color, etc. entre añadidos y original. Durante años ha venido siendo habitual el empleo de sustancias naturales tintóreas en el teñido de textiles, tal es el caso del café. El presente trabajo pretende ser una primera aproximación al uso del café como sustancia tintórea y a su vez establecer su efectividad en la tinción de tejidos de seda utilizados como piezas de refuerzo en los tratamientos de consolidación textil. Para ello, se ha optimizado el proceso de tinción con este colorante natural usando distintas recetas procedentes de tratados especializados (tanto en lo referente a métodos de tinción directa y con pretratamiento con agentes mordientes como alumbre,m dicromato potásico o sulfato de cobre). Posteriormente, se han evaluado los efectos de las distintas variantes de los procesos de tinción mediante análisis colorimétrico, microscopia óptica y microscopia electrónica (SEM/EDX). Los resultados obtenidos establecen que se ha alcanzado una óptima gama de tonalidades muy similares a los tejidos de seda históricos, con lo que podrían ser utilizados en los tratamientos de consolidación textil., Textile consolidation is one of the most technically and ethically awkward procedures in the intervention on ancient fabrics. This treatment always brings up issues about the reversibility of materials and methods, particularly in cases in which the extreme degradation of the fabric requires the application of an adhesive substance to reinforce the fibres and re-establish their consistency from the inside. Sewing systems nevertheless constitute a valid and efficient alternative in the case of slightly deteriorated items that barely need any further minimum reinforcement. Hence, the application of reinforcement pieces by sewing these on is similarly useful in the case of treatments for replacement of missing pieces of the original fabric, where one can see a need for likening both the textile characteristics and their chemical nature, colour, etc. of the items added and the original. The use of natural substances for dyeing fabrics, as is the case of coffee, has been a common practice for years. This work sets out to be a first approach to the use of coffee as a dye and in turn to establish its effectiveness in dyeing silk fabrics used as reinforcement items in textile consolidation processes. This was done by optimising the dyeing process with this natural colorant, using different recipes from specialised treatises (both as regards direct dyeing methods and those applying a pre-treatment with mordant agents such as alum, potassium dichromate or copper sulphate). Later on, the effects of the different variants in the dyeing processes were assessed by means of colorimetric analysis, optical microscopy and electronic microscopy (SEM/EDX). The results obtained establish that an optimum range of tones very similar to historic silk fabrics has been attained, thus meaning that these can be used in textile consolidation treatments.

La consolidación textil se encuentra entre los procedimientos de mayor compromiso técnico y ético en la intervención de tejidos históricos. Dicho tratamiento plantea siempre cuestiones acerca de la reversibilidad de materiales y métodos especialmente en aquellos casos en los que la extrema degradación del tejido requiere la aplicación de una sustancia adhesiva que refuerce las fibras y restablezca su consistencia desde su interior. Sin embargo, los sistemas mediante costura ofrecen una alternativa válida y eficiente en el caso de piezas levemente degradadas que apenas necesitan un refuerzo mínimo adicional. Así mismo, la aplicación de piezas de refuerzo mediante costura es igualmente útil en el caso de los tratamientos de reposición de faltantes del tejido original, donde se evidencia la necesidad de asemejar tanto las características textiles como su naturaleza química, color, etc. entre añadidos y original. Durante años ha venido siendo habitual el empleo de sustancias naturales tintóreas en el teñido de textiles, tal es el caso del café. El presente trabajo pretende ser una primera aproximación al uso del café como sustancia tintórea y a su vez establecer su efectividad en la tinción de tejidos de seda utilizados como piezas de refuerzo en los tratamientos de consolidación textil. Para ello, se ha optimizado el proceso de tinción con este colorante natural usando distintas recetas procedentes de tratados especializados (tanto en lo referente a métodos de tinción directa y con pretratamiento con agentes mordientes como alumbre,m dicromato potásico o sulfato de cobre). Posteriormente, se han evaluado los efectos de las distintas variantes de los procesos de tinción mediante análisis colorimétrico, microscopia óptica y microscopia electrónica (SEM/EDX). Los resultados obtenidos establecen que se ha alcanzado una óptima gama de tonalidades muy similares a los tejidos de seda históricos, con lo que podrían ser utilizados en los tratamientos de consolidación textil., Textile consolidation is one of the most technically and ethically awkward procedures in the intervention on ancient fabrics. This treatment always brings up issues about the reversibility of materials and methods, particularly in cases in which the extreme degradation of the fabric requires the application of an adhesive substance to reinforce the fibres and re-establish their consistency from the inside. Sewing systems nevertheless constitute a valid and efficient alternative in the case of slightly deteriorated items that barely need any further minimum reinforcement. Hence, the application of reinforcement pieces by sewing these on is similarly useful in the case of treatments for replacement of missing pieces of the original fabric, where one can see a need for likening both the textile characteristics and their chemical nature, colour, etc. of the items added and the original. The use of natural substances for dyeing fabrics, as is the case of coffee, has been a common practice for years. This work sets out to be a first approach to the use of coffee as a dye and in turn to establish its effectiveness in dyeing silk fabrics used as reinforcement items in textile consolidation processes. This was done by optimising the dyeing process with this natural colorant, using different recipes from specialised treatises (both as regards direct dyeing methods and those applying a pre-treatment with mordant agents such as alum, potassium dichromate or copper sulphate). Later on, the effects of the different variants in the dyeing processes were assessed by means of colorimetric analysis, optical microscopy and electronic microscopy (SEM/EDX). The results obtained establish that an optimum range of tones very similar to historic silk fabrics has been attained, thus meaning that these can be used in textile consolidation treatments.

La consolidación textil se encuentra entre los procedimientos de mayor compromiso técnico y ético en la intervención de tejidos históricos. Dicho tratamiento plantea siempre cuestiones acerca de la reversibilidad de materiales y métodos especialmente en aquellos casos en los que la extrema degradación del tejido requiere la aplicación de una sustancia adhesiva que refuerce las fibras y restablezca su consistencia desde su interior. Sin embargo, los sistemas mediante costura ofrecen una alternativa válida y eficiente en el caso de piezas levemente degradadas que apenas necesitan un refuerzo mínimo adicional. Así mismo, la aplicación de piezas de refuerzo mediante costura es igualmente útil en el caso de los tratamientos de reposición de faltantes del tejido original, donde se evidencia la necesidad de asemejar tanto las características textiles como su naturaleza química, color, etc. entre añadidos y original. Durante años ha venido siendo habitual el empleo de sustancias naturales tintóreas en el teñido de textiles, tal es el caso del café. El presente trabajo pretende ser una primera aproximación al uso del café como sustancia tintórea y a su vez establecer su efectividad en la tinción de tejidos de seda utilizados como piezas de refuerzo en los tratamientos de consolidación textil. Para ello, se ha optimizado el proceso de tinción con este colorante natural usando distintas recetas procedentes de tratados especializados (tanto en lo referente a métodos de tinción directa y con pretratamiento con agentes mordientes como alumbre,m dicromato potásico o sulfato de cobre). Posteriormente, se han evaluado los efectos de las distintas variantes de los procesos de tinción mediante análisis colorimétrico, microscopia óptica y microscopia electrónica (SEM/EDX). Los resultados obtenidos establecen que se ha alcanzado una óptima gama de tonalidades muy similares a los tejidos de seda históricos, con lo que podrían ser utilizados en los tratamientos de consolidación textil., Textile consolidation is one of the most technically and ethically awkward procedures in the intervention on ancient fabrics. This treatment always brings up issues about the reversibility of materials and methods, particularly in cases in which the extreme degradation of the fabric requires the application of an adhesive substance to reinforce the fibres and re-establish their consistency from the inside. Sewing systems nevertheless constitute a valid and efficient alternative in the case of slightly deteriorated items that barely need any further minimum reinforcement. Hence, the application of reinforcement pieces by sewing these on is similarly useful in the case of treatments for replacement of missing pieces of the original fabric, where one can see a need for likening both the textile characteristics and their chemical nature, colour, etc. of the items added and the original. The use of natural substances for dyeing fabrics, as is the case of coffee, has been a common practice for years. This work sets out to be a first approach to the use of coffee as a dye and in turn to establish its effectiveness in dyeing silk fabrics used as reinforcement items in textile consolidation processes. This was done by optimising the dyeing process with this natural colorant, using different recipes from specialised treatises (both as regards direct dyeing methods and those applying a pre-treatment with mordant agents such as alum, potassium dichromate or copper sulphate). Later on, the effects of the different variants in the dyeing processes were assessed by means of colorimetric analysis, optical microscopy and electronic microscopy (SEM/EDX). The results obtained establish that an optimum range of tones very similar to historic silk fabrics has been attained, thus meaning that these can be used in textile consolidation treatments.

La consolidación textil se encuentra entre los procedimientos de mayor compromiso técnico y ético en la intervención de tejidos históricos. Dicho tratamiento plantea siempre cuestiones acerca de la reversibilidad de materiales y métodos especialmente en aquellos casos en los que la extrema degradación del tejido requiere la aplicación de una sustancia adhesiva que refuerce las fibras y restablezca su consistencia desde su interior. Sin embargo, los sistemas mediante costura ofrecen una alternativa válida y eficiente en el caso de piezas levemente degradadas que apenas necesitan un refuerzo mínimo adicional. Así mismo, la aplicación de piezas de refuerzo mediante costura es igualmente útil en el caso de los tratamientos de reposición de faltantes del tejido original, donde se evidencia la necesidad de asemejar tanto las características textiles como su naturaleza química, color, etc. entre añadidos y original. Durante años ha venido siendo habitual el empleo de sustancias naturales tintóreas en el teñido de textiles, tal es el caso del café. El presente trabajo pretende ser una primera aproximación al uso del café como sustancia tintórea y a su vez establecer su efectividad en la tinción de tejidos de seda utilizados como piezas de refuerzo en los tratamientos de consolidación textil. Para ello, se ha optimizado el proceso de tinción con este colorante natural usando distintas recetas procedentes de tratados especializados (tanto en lo referente a métodos de tinción directa y con pretratamiento con agentes mordientes como alumbre,m dicromato potásico o sulfato de cobre). Posteriormente, se han evaluado los efectos de las distintas variantes de los procesos de tinción mediante análisis colorimétrico, microscopia óptica y microscopia electrónica (SEM/EDX). Los resultados obtenidos establecen que se ha alcanzado una óptima gama de tonalidades muy similares a los tejidos de seda históricos, con lo que podrían ser utilizados en los tratamientos de consolidación textil., Textile consolidation is one of the most technically and ethically awkward procedures in the intervention on ancient fabrics. This treatment always brings up issues about the reversibility of materials and methods, particularly in cases in which the extreme degradation of the fabric requires the application of an adhesive substance to reinforce the fibres and re-establish their consistency from the inside. Sewing systems nevertheless constitute a valid and efficient alternative in the case of slightly deteriorated items that barely need any further minimum reinforcement. Hence, the application of reinforcement pieces by sewing these on is similarly useful in the case of treatments for replacement of missing pieces of the original fabric, where one can see a need for likening both the textile characteristics and their chemical nature, colour, etc. of the items added and the original. The use of natural substances for dyeing fabrics, as is the case of coffee, has been a common practice for years. This work sets out to be a first approach to the use of coffee as a dye and in turn to establish its effectiveness in dyeing silk fabrics used as reinforcement items in textile consolidation processes. This was done by optimising the dyeing process with this natural colorant, using different recipes from specialised treatises (both as regards direct dyeing methods and those applying a pre-treatment with mordant agents such as alum, potassium dichromate or copper sulphate). Later on, the effects of the different variants in the dyeing processes were assessed by means of colorimetric analysis, optical microscopy and electronic microscopy (SEM/EDX). The results obtained establish that an optimum range of tones very similar to historic silk fabrics has been attained, thus meaning that these can be used in textile consolidation treatments.

Badger Army Ammunition Plant (BAAAP), in Sauk County, Wisconsin, is one of many inactive Army ammunition plants currently under the control of the Department of Defense (DoD) with transitioning missions in place. These plants are in varying stages of transfer out of DoD control. In order to transfer these properties, DoD must characterize and decontaminate the properties to a level protective of human health and the environment. To accomplish this task, many buildings used in the production, loading, handling, and storage of explosives will have to be demolished or characterized and decontaminated. BAAAP alone has more than 1,400 buildings on the installation that have to be addressed. The contaminants of concern associated with the buildings at BAAAP include nitrocellulose (NC), nitroglycerine (NG), dinitrotoluene (DNT), and common environmental compounds such as asbestos-containing material (ACM), solvents, and metals. A previous Environmental Security Technology Certification Program (ESTCP) demonstration was performed between April 28, 2002, and May 13, 2002, to demonstrate candidate field test methods for NC and NG. The methods evaluated were Raman spectroscopy, EXPRAYTM colorimetric indicator, and the Cold Regions Research and Engineering Laboratory (CRREL) Royal Demolition Xplosive (RDX) colorimetric field screening method. The methods were used to test for the presence and/or concentration of NC or NG in soil samples and concrete slabs. Attempts were made to compare the results from these field measurements to laboratory analyses of NC and NG in the same materials to evaluate the reliability of the field screening and analytical methods for identifying and quantifying NC and NG in buildings and soils.

Digital images of overcast skies as seen from the earth's surface open new windows onto the angular details of overcast colors and visible-wavelength spectra. After calibration with a spectroradiometer, a commercial CCD camera equipped with a fisheye lens can produce colorimetrically accurate all-sky maps of overcast spectra. Histograms and azimuthally averaged curves of the resulting chromaticities show consistent, but unexpected, patterns in time-averaged overcast colors. Although widely used models such as LOWTRAN7 and MODTRAN4 cannot explain these characteristic patterns, a simple semiempirical model based on the radiative transfer equation does, and it provides insights into the visible consequences of absorption and scattering both within and beneath overcasts., Published in Applied Optics, v47 n34 pH106-H115, December 2008.

This paper describes the use of cochineal natural dye in old cotton textiles. Cochineal-dyed cotton samples were prepared in the laboratory with the use of old materials and formulas. Firstly, the characterization of samples through chemical and mechanical tests helped establish standards for comparisons with current textiles. The identification of carminic acid and mordant agents was performed by spectrophotometric, microscopic and chromatographic techniques. Secondly, tensile tests were run in a weft direction. Stress-strained curves helped determine the stiffness and flexibility of each sample as well as their elongation and their probability of tearing under specific environmental conditions. The objective of this research is to determine the effects of dyeing and mordanting on the mechanical properties of cotton fabrics. Cochineal was used to represent natural dyes for experimental testing purposes. The mordants selected included Tin(IV) chloride, Copper sulphate, Potassium dichromate, Ferrous sulphate and Alum., La presente investigación detalla el empleo de la cochinilla como tinte natural de tejidos de algodón en piezas textiles de valor histórico. A partir del volcado y optimización de recetarios y fórmulas tradicionales son elaboradas muestras de referencia mediante procesos de tinción directa y con mordientes. La fibra de algodón, el ácido carmínico presente en la cochinilla así como los mordientes son caracterizados mediante técnicas espectroscópicas (Espectrofotometría UV-Vis), cromatográficas (HPLC-DAD) y microscópicas (MO y SEM/EDX). Así mismo, han sido desarrollados ensayos de tracción en sentido trama para cada una de las muestras. A partir de las curvas esfuerzo deformación obtenidas, el estudio plantea la comparación entre el comportamiento de cada una de las muestras atendiendo a cuestiones tales como la flexibilidad y rigidez así como su capacidad de elongación y resistencia máxima en determinadas condiciones de temperatura y humedad. Los resultados obtenidos demuestran que los diversos procesos de tinción provocan diferente respuesta en las propiedades mecánicas y dimensionales del tejido tratado, observándose una gradación de comportamiento dependiendo del agente de mordentado empleado.

This paper describes the use of cochineal natural dye in old cotton textiles. Cochineal-dyed cotton samples were prepared in the laboratory with the use of old materials and formulas. Firstly, the characterization of samples through chemical and mechanical tests helped establish standards for comparisons with current textiles. The identification of carminic acid and mordant agents was performed by spectrophotometric, microscopic and chromatographic techniques. Secondly, tensile tests were run in a weft direction. Stress-strained curves helped determine the stiffness and flexibility of each sample as well as their elongation and their probability of tearing under specific environmental conditions. The objective of this research is to determine the effects of dyeing and mordanting on the mechanical properties of cotton fabrics. Cochineal was used to represent natural dyes for experimental testing purposes. The mordants selected included Tin(IV) chloride, Copper sulphate, Potassium dichromate, Ferrous sulphate and Alum., La presente investigación detalla el empleo de la cochinilla como tinte natural de tejidos de algodón en piezas textiles de valor histórico. A partir del volcado y optimización de recetarios y fórmulas tradicionales son elaboradas muestras de referencia mediante procesos de tinción directa y con mordientes. La fibra de algodón, el ácido carmínico presente en la cochinilla así como los mordientes son caracterizados mediante técnicas espectroscópicas (Espectrofotometría UV-Vis), cromatográficas (HPLC-DAD) y microscópicas (MO y SEM/EDX). Así mismo, han sido desarrollados ensayos de tracción en sentido trama para cada una de las muestras. A partir de las curvas esfuerzo deformación obtenidas, el estudio plantea la comparación entre el comportamiento de cada una de las muestras atendiendo a cuestiones tales como la flexibilidad y rigidez así como su capacidad de elongación y resistencia máxima en determinadas condiciones de temperatura y humedad. Los resultados obtenidos demuestran que los diversos procesos de tinción provocan diferente respuesta en las propiedades mecánicas y dimensionales del tejido tratado, observándose una gradación de comportamiento dependiendo del agente de mordentado empleado.

This paper describes the use of cochineal natural dye in old cotton textiles. Cochineal-dyed cotton samples were prepared in the laboratory with the use of old materials and formulas. Firstly, the characterization of samples through chemical and mechanical tests helped establish standards for comparisons with current textiles. The identification of carminic acid and mordant agents was performed by spectrophotometric, microscopic and chromatographic techniques. Secondly, tensile tests were run in a weft direction. Stress-strained curves helped determine the stiffness and flexibility of each sample as well as their elongation and their probability of tearing under specific environmental conditions. The objective of this research is to determine the effects of dyeing and mordanting on the mechanical properties of cotton fabrics. Cochineal was used to represent natural dyes for experimental testing purposes. The mordants selected included Tin(IV) chloride, Copper sulphate, Potassium dichromate, Ferrous sulphate and Alum., La presente investigación detalla el empleo de la cochinilla como tinte natural de tejidos de algodón en piezas textiles de valor histórico. A partir del volcado y optimización de recetarios y fórmulas tradicionales son elaboradas muestras de referencia mediante procesos de tinción directa y con mordientes. La fibra de algodón, el ácido carmínico presente en la cochinilla así como los mordientes son caracterizados mediante técnicas espectroscópicas (Espectrofotometría UV-Vis), cromatográficas (HPLC-DAD) y microscópicas (MO y SEM/EDX). Así mismo, han sido desarrollados ensayos de tracción en sentido trama para cada una de las muestras. A partir de las curvas esfuerzo deformación obtenidas, el estudio plantea la comparación entre el comportamiento de cada una de las muestras atendiendo a cuestiones tales como la flexibilidad y rigidez así como su capacidad de elongación y resistencia máxima en determinadas condiciones de temperatura y humedad. Los resultados obtenidos demuestran que los diversos procesos de tinción provocan diferente respuesta en las propiedades mecánicas y dimensionales del tejido tratado, observándose una gradación de comportamiento dependiendo del agente de mordentado empleado.

This paper describes the use of cochineal natural dye in old cotton textiles. Cochineal-dyed cotton samples were prepared in the laboratory with the use of old materials and formulas. Firstly, the characterization of samples through chemical and mechanical tests helped establish standards for comparisons with current textiles. The identification of carminic acid and mordant agents was performed by spectrophotometric, microscopic and chromatographic techniques. Secondly, tensile tests were run in a weft direction. Stress-strained curves helped determine the stiffness and flexibility of each sample as well as their elongation and their probability of tearing under specific environmental conditions. The objective of this research is to determine the effects of dyeing and mordanting on the mechanical properties of cotton fabrics. Cochineal was used to represent natural dyes for experimental testing purposes. The mordants selected included Tin(IV) chloride, Copper sulphate, Potassium dichromate, Ferrous sulphate and Alum., La presente investigación detalla el empleo de la cochinilla como tinte natural de tejidos de algodón en piezas textiles de valor histórico. A partir del volcado y optimización de recetarios y fórmulas tradicionales son elaboradas muestras de referencia mediante procesos de tinción directa y con mordientes. La fibra de algodón, el ácido carmínico presente en la cochinilla así como los mordientes son caracterizados mediante técnicas espectroscópicas (Espectrofotometría UV-Vis), cromatográficas (HPLC-DAD) y microscópicas (MO y SEM/EDX). Así mismo, han sido desarrollados ensayos de tracción en sentido trama para cada una de las muestras. A partir de las curvas esfuerzo deformación obtenidas, el estudio plantea la comparación entre el comportamiento de cada una de las muestras atendiendo a cuestiones tales como la flexibilidad y rigidez así como su capacidad de elongación y resistencia máxima en determinadas condiciones de temperatura y humedad. Los resultados obtenidos demuestran que los diversos procesos de tinción provocan diferente respuesta en las propiedades mecánicas y dimensionales del tejido tratado, observándose una gradación de comportamiento dependiendo del agente de mordentado empleado.

This paper describes the use of cochineal natural dye in old cotton textiles. Cochineal-dyed cotton samples were prepared in the laboratory with the use of old materials and formulas. Firstly, the characterization of samples through chemical and mechanical tests helped establish standards for comparisons with current textiles. The identification of carminic acid and mordant agents was performed by spectrophotometric, microscopic and chromatographic techniques. Secondly, tensile tests were run in a weft direction. Stress-strained curves helped determine the stiffness and flexibility of each sample as well as their elongation and their probability of tearing under specific environmental conditions. The objective of this research is to determine the effects of dyeing and mordanting on the mechanical properties of cotton fabrics. Cochineal was used to represent natural dyes for experimental testing purposes. The mordants selected included Tin(IV) chloride, Copper sulphate, Potassium dichromate, Ferrous sulphate and Alum., La presente investigación detalla el empleo de la cochinilla como tinte natural de tejidos de algodón en piezas textiles de valor histórico. A partir del volcado y optimización de recetarios y fórmulas tradicionales son elaboradas muestras de referencia mediante procesos de tinción directa y con mordientes. La fibra de algodón, el ácido carmínico presente en la cochinilla así como los mordientes son caracterizados mediante técnicas espectroscópicas (Espectrofotometría UV-Vis), cromatográficas (HPLC-DAD) y microscópicas (MO y SEM/EDX). Así mismo, han sido desarrollados ensayos de tracción en sentido trama para cada una de las muestras. A partir de las curvas esfuerzo deformación obtenidas, el estudio plantea la comparación entre el comportamiento de cada una de las muestras atendiendo a cuestiones tales como la flexibilidad y rigidez así como su capacidad de elongación y resistencia máxima en determinadas condiciones de temperatura y humedad. Los resultados obtenidos demuestran que los diversos procesos de tinción provocan diferente respuesta en las propiedades mecánicas y dimensionales del tejido tratado, observándose una gradación de comportamiento dependiendo del agente de mordentado empleado.

Colorimetric and spectral characteristics of pyrimidinylformazanes and their complexes with transition-metal ions are studied in solution and on solids. Reagents suitable for the visual determination of copper(II) and silver(I) ions and for the sorption spectroscopic determination of copper(II) ions are recognized. © Pleiades Publishing, Inc., 2006., This work was supported by the Russian Foundation for Basic Research, project no. 05-03-32023.

Colorimetric and spectral characteristics of pyrimidinylformazanes and their complexes with transition-metal ions are studied in solution and on solids. Reagents suitable for the visual determination of copper(II) and silver(I) ions and for the sorption spectroscopic determination of copper(II) ions are recognized. © Pleiades Publishing, Inc., 2006., This work was supported by the Russian Foundation for Basic Research, project no. 05-03-32023.

This curriculum unit from Cornell Science Inquiry Partnerships aims to teach students about colorimetric analysis by using a calibration curve to determine the concentration of iron in liquid vitamin supplements. The lab was intended for use with honors or AP high school chemistry classes and gives them experience working with real world samples in the lab.

Previous aqueous studies using HD pre-dissolved in isopropanol have shown that the effectiveness of HD enzymatic degradation is a function of the homogeneity of the HD-water system. In this study, a microtiter plate assay was developed for the purpose of screening a series of compounds with the potential to increase the solubility or dispersion of HD in an aqueous matrix. The assay used meta-cresol purple dye as a pH indicator in a series of buffer concentrations to monitor the acid produced from HD hydrolysis. The extent of hydrolysis could be observed colorimetrically in a time-controlled series of reactions that allowed simultaneous comparison of numerous compounds or conditions on a single microtiter plate. Sixty-seven different detergents, surfactants, or different concentrations thereof were screened to determine their effect on HD hydrolysis rate. All were observed to inhibit HD hydrolysis. The simplest explanation of the results observed was probably that the micelles effectively sequestered the HD molecules from water in a hydrophobic environment., The original document contains color images.

Time-series measurements of daylight (skylight plus direct sunlight) spectra beneath overcast skies reveal an unexpectedly wide gamut of pastel colors. Analyses of these spectra indicate that at visible wavelengths, overcasts are far from spectrally neutral transmitters of the daylight incident on their tops. Colorimetric analyses show that overcasts make daylight bluer and that the amount of bluing increases with cloud optical depth. Simulations using the radiative-transfer model MODTRAN4 help explain the observed bluing: multiple scattering within optically thick clouds greatly enhances spectrally selective absorption by water droplets. However, other factors affecting overcast colors seen from below range from minimal (cloud-top heights) to moot (surface colors)., Published in Applied Optics, v44 n27 p5712-5722, 20 September 2005.