Color Strips Research Articles

Association between Vaginal Micro-environment Disorder and Cervical Intraepithelial Neoplasia in a Community Based Population in China.

There are other factors that contribute to cervical carcinogenesis except HPV infection. This study aimed to investigate the association between vaginal micro-environment factors, including H2O2, vaginal PH value, vagina cleanness, β-glucuronidase, coagulase, neuraminidase and leukocyte esterase and cervical intraeipithelial neoplasia (CIN). In total 1019 participants, including 623 normal cervical (NC) women, 303 patients with low-grade cervical intraepithelial neoplasia (CIN1) and 93 patients with high-grade cervical intraepithelial neoplasia (CIN2/3), were enrolled into the study. HPV genotyping was detected by flow-through hybridization and gene chip. Vaginal H2O2, β-glucuronidase, coagulase, neuraminidase and leukocyte esterase were detected by Aerobic Vaginitis (AV) / Bacterial Vaginal Disease (BV) Five Joint Test Kit. Vaginal PH was measured on the glass slide after microscopy, using color strips with a PH range of 3.8-5.4. Vagina cleanness was determined according to the National Clinical Laboratory Practice Guideline. χ2test and Logistic regression were operated using SPSS 22.0 software. Our results showed that HPV16 infection rate and the abnormal rates of H2O2, PH, vagina cleanness, β-glucuronidase or neuraminidase increased gradually along with the severity of CIN (P<0.05). Abnormities of H2O2, cleanness, β-glucuronidase and neuraminidase were risk factors for CIN regardless of HPV16 infection, furthermore, abnormities of PH value, leukocyte esterase could also increase the risk of CIN in HPV16 positive group. In addition, women with abnormal vaginal micro-environment factors in HPV16 positive group had a significantly higher risk of developing CIN than HPV16 negative group. The results from generalized multifactor dimensionality reduction (GMDR) model showed that there was interaction effect with abnormities of vagina cleanness, H2O2, β-glucuronidase and neuraminidase on CIN2/3 in HPV16 negative group, while, there was interaction effect with abnormities of vagina cleanness, β-glucuronidase and neuraminidase on CIN1 and with abnormities of vagina cleanness, PH, H2O2, β-glucuronidase, neuraminidase and leukocyte esterase on CIN2/3 in HPV16 positive group. Our results suggested that vaginal micro-environment disorder could increase the risk of CIN, especially, the abnormality of H2O2, cleanness, β-glucuronidase and neuraminidase. There were interaction effects with abnormities of H2O2, vagina cleanness, β-glucuronidase and neuraminidase on CIN whether HPV16 was infected or not.

Comparison of Current–Voltage Response to Diagnostic X-rays of Five Light-Emitting Diode Strips

Light-emitting diodes (LEDs) have miscellaneous applications owing to their low cost, small size, flexibility, and commercial availability. Furthermore, LEDs have dual applicability as light emitters and detectors. This study explores the current–voltage (C–V) response of LED strips exposed to diagnostic x-rays. Cold white, warm white, red, green, and blue LED strip colors were tested. Each strip consisted of 12 LED chips and was connected to a multimeter. The variable diagnostic x-ray parameters evaluated were kilovoltage peak (kVp), milliampere-seconds (mAs), and source-to-image distance (SID). The radiation dose was also measured using a dosimeter simultaneously exposed to x-rays perpendicularly incident on the strips. Lastly, the consistency of C–V responses, and any possible degradation after 1–2 months was also analyzed. Each LED strip color was ranked according to its C–V response in each of the investigated parameters. The LED strip color with the best cumulative rank across all the tested parameters was then examined for reproducibility. Our findings revealed that the C–V responses of LED strips are (a) generally low but measurable, (b) inconsistent and fluctuating as a consequence of kVp variations, (c) positively correlated to mAs, (d) negatively correlated to SID, and (e) positively correlated to dose. Overall results suggested cold white LED strip as most feasible for x-ray detection—in comparison to examined colors. Additionally, the reproducibility study using the cold white LED strip found a similar trend of C–V response to all variables except kVp. Outcomes indicate that LED strips have the potential to be exploited for detecting low dose (~0–100 mGy) diagnostic x-rays. However, future studies should be carried out to increase the low C–V signal.

Application of Ozone in Stripping of Cotton Fabric Dyed with Reactive Dyes

ABSTRACT This paper discusses the color stripping of cotton fabric dyed with four reactive dyes using ozone. An ozone color stripping process has been optimized in terms of pH, ozone dose, treatment time and dye concentration. Color stripping efficiency of the process is evaluated in light of the color properties including Lightness (L*), Lightness Difference (∆L*), and Color Difference (∆E*) in addition to strength properties, i.e., copper number and degree of polymerization as well as compared with a control method (conventional reductive color stripping method). The results demonstrate maximum color stripping at an ozone dose of 10 g/h, exposure time of 45 min, and pH maintained at 5. The Stripping Efficiency, however, decreases with increasing dye concentration from 0.5% to 4%, which implies that decolorization of dyed fabric with higher initial dye concentration requires higher ozone dose and/or longer exposure time. The strength of the ozone-stripped fabric sample is almost similar to that of control. The chemical oxygen demand of effluent generated by ozone stripping process is 97% lower than the effluent produced by the conventional stripping method. The Ozone Stripping Process hence proves to be environment-friendly as it consumes less water, energy, and chemicals.

American Society of Cinematographers Motion Imaging Technology Council Progress Report 2019

Since its formation 100 years ago on 8 January 1919, the American Society of Cinematographers (ASC) has been consistently focused on the motion imaging technologies that underpin and enable the cinematographer’s creative toolset essential to artistic expression in narrative storytelling. From cameras, lenses, lighting, exposure metering and camera support equipment to the evolution of film stocks from BW (orthochromatic/panchromatic) to color (2 strip/3 strip Technicolor and eventually integral tri-pack single strip color from Eastman Kodak, the ASC and its cinematographer members have consistently been at the forefront of critical technology developments that have influenced the advancement of their art form.

Evolution of Using Color Guides in Offset Lithography Printing

Research subject: Design Color Chart for Spot Pre-colored Inks as a guide for Offset Lithography Printing. Objetive: Studying the types of color guides and Its efficiency and importance in the print production. - Explain the importance of using Pantone Color Manager program in print production. - Using of the global language of color production. The problem: neglecting the role of color guides as a basic partner in all steps of print production as a tool that coordinates color standards through a special numbering system, color strips and a global language for color characterization, to achieve the high level of print quality in the Egyptian market.

Electro-Optical Gas Sensor Consisting of Nanostructured Paper Coating and an Ultrathin Sensing Element

This work describes the use of a paper substrate for electro-optical detection of toxic hydrogen sulfide (H2S) gas. For electrical detection, a chemiresistive type of gas sensor was developed. Ultrathin gold film electrodes (UTGFE) were produced by physical vapor deposition of gold on nanostructured latex-coated paper substrate. The gas-sensing film was deposited on the electrodes by inkjet printing. The sensing films were characterized by atomic force microscopy, X-ray photoelectron spectroscopy and conductometry. The sensing films showed more than seven orders of magnitude change in resistance when exposed to as low as 1 part per million (ppm) H2S gas at room temperature. Besides resistive response, the change in color of the sensing films was studied on a paper substrate, both as a function of print density of the sensing material and H2S concentration. For quantification of the analyte the red, green and blue color deconvolution was performed on the pictures of the paper strip indicator using an open source software. A clear response was obtained from the blue channel. The inexpensive disposable color strips produced on the paper substrate can be used for qualitative and quantitative detection (as low as 1.5 ppm) of H2S gas.

CORRELATIONS BETWEEN FRUIT’S YIELD WITH HORTICULTURAL TRAITS AND INHERITANCE OF MORPHOLOGICAL TRAITS OF SPONGE GOURD (LUFFA CYLINDRICA)

Abstract: Enhancing the production yield fornew generations of each horticultural crop needseffective selecting programs to find outexcellent traits forming thisfruit yield. Therefore,this study aims to investigate the correlations between the fruit yield withhorticultural traits, mainly with yield’s components and inheritance of some morphological traitsofsponge gourd (Luffa cylindrica). An F2 population was generated from a cross between sponge gourds GBVN006904 (male) and GBVN005333 (female) at University of Agriculture and Forestry, Hue University,Vietnam. The positive correlations are observed between the fruit yield per plant andthe fruit diameter, fruit weight, and number of fruits per plant (0.901**). The male first flower appearance time showsa significant positive correlation with female first flower appearance one. The peduncle length correlates positively with the fruit length. The fruit length is enhanced when fruit weight increases. The total soluble solids and fruit diameter show a slightly negative correlation. Chi-square analysis for the leaf shape, depth of lobing, leaf color, and leaf pubescence shows a good fit to a ratio of 9:6:1, thus being controlled by duplicate genes interaction. The fruit color (dark-green:light-green) fits well to a ratio of 15:1, giving its control to duplicate genes with dark-green color being dominant, whereas the fruit shape assorts independently according toa ratio of 9:3:3:1. The fruit stripe color exhibits monogenic incomplete dominance, and the curvature of the fruit is a monogenic recessive trait. Fruit yield components, such as the number of fruit per plant, the fruit weight, and the fruit diameter,strongly affect the fruit yield of sponge gourd. The inheritance of morphological traits indicates that most of the traits are controlled by complete dominance at both gene pairs excepted for fruit strip color and curvature of fruit.Keywords: correlation, inheritance, morphological traits, sponge gourd, yield components

The Diagnostic Value of Leukocyte Esterase Reagent Dip-stick in Spontaneous Bacterial Peritonitis Diagnosis in Patients with Liver Cirrhosis

Background: Spontaneous bacterial peritonitis (SBP) is a serious complication of advanced liver cirrhosis which requires rapid diagnosis for the initiation of proper antibiotic therapy. Manual examination of ascetic fluid is a rather time-consuming procedure. The leukocyte esterase (LE) reagent dipstick is based on the esterase activity of activated granulocytes which reacts with an ester‑releasing hydroxyphenylpyrrole causing a color change in the azo dye of reagent strip. Aim: the aim of this study was to evaluate the diagnostic value of leukocyte esterase reagent dipstick in SBP diagnosis in patients with liver cirrhosis attending Suez Canal University Hospital. Methods: ascetic fluid cell count using the counting chamber method was compared to Leucocyte Esterase strip rapid test in two groups of patients (65 ABP vs 65 non-SBP). The strips were read in 120 seconds using colorimetric 5-grade scale (from 0 to 4). The grades (0-2) were considered a negative test while grades (3-4) were considered a positive one. Results: Comparison of the SBP +ve and -ve groups showed a sensitivity of LE strips of (82%) with a high specificity (94 %), PPV (93 %) and NPV (84 %) for the diagnosis of SBP. A good correlation between the LE strip color grade and the ascetic fluid PMNL cell count number (P<0.05) Conclusion: the leukocyte esterase reagent dipstick test is a rather specific, rapid, inexpensive and simple bedside method for diagnosis of SBP method for. A negative LE test result excludes SBP with a high accuracy.

Color stripping of reactive-dyed cotton fabric in a UV/sodium hydrosulfite system with a dipping manner at low temperature

Color stripping is one of the most convenient approaches for amending various shade faults during dyeing and printing processes. However, conventional stripping processes usually bring a serious risk of environment pollution. The purpose of this work is to develop a novel, sustainable and energy-conserving method for stripping of reactive-dyed cotton substrate by employing a UV/Na2S2O4 system, in which low dosage of sodium hydrosulfite (Na2S2O4) was involved and induced by UV photocatalysis at atmospheric temperature. The effects of stripping parameters such as initial pH value of working solution, temperature and stripping duration on color stripping efficiency and fabric tensile strength were investigated. The results show that the fixed reactive dyes on cotton could be efficiently stripped in the UV/Na2S2O4 system with a photocatalytic initiation and a dipped stripping manner, along with relatively high tensile strength retention by the substrate. Moreover, an optimized photocatalytic color stripping process was recommended for degradation or stripping of the fixed reactive dye molecules in cotton fibers. Furthermore, a successful application of the proposed system was also achieved for stripping a series of the Evercion/Everlight and Megafix reactive dyes fixed on cotton. In addition, the color stripping was further successfully investigated and validated via the variations in structures and surface morphologies of the cotton fibers by utilizing Fourier transform infrared spectrometry, wide-angle X-ray diffraction and scanning electron microscopy analysis.

The Spectral Analysis of Labor Force and Profit of Construction Materials Distribution Companies in Romania Analogue Spectrum of Light in Physics

In physics, spectral studies have been observed and quantified since 1822 when Fourier J. (1822) used them in his analysis of thermal conduction. Further, Balmer (1885), studying the hydrogen atom, noticed the existence of the four lengths waveform which characterize the spectrum of the hydrogen atom. Following the research, it determined the number of 364.6 nm that was identified in each hydrogen spectral line. Therefore, Balmer determined the equation to determine the wavelength of the emission or absorption lines. Three years later, physicist Johannes Rydberg generalized Balmer's equation, thus determining the constant Rydberg. Rutherford's model was later improved and in 1913 was introduced Bohr's model and converts justify empirical results in terms of fundamental physical constants. Subsequently, a significant number of physicists approached the spectral analyzes of electromagnetic radiation (in different fields: ultraviolet, X-rays, infrared) and analyzed their characteristics: frequency, amplitude, spectral density. In the economy, the first papers that dealt with spectral analysis emerged in 1960 and consisted of the analysis of seasonal adjustment procedures for time series at macroeconomic level. Starting from the cross-spectral methods were developed methods such as analysis of the movement in the series, the time-frequency methods, etc. The fluctuating nature of the activities of different sectors of activity involves different oscillations in terms of amplitude and frequency, but also oscillations characterized by a higher or lower propagation period, which determines the evolution of economic indicators. We can classify the propagation periods of activities according to the level of the characteristics that determine them in time units (time intervals). Thus, the oscillation frequency will be given by the number of periods of propagation activities. Depending on the oscillation period will determine their average, and the amplitude of oscillation is determined by peak line and the average determined. Starting from the ultraviolet spectrum in physics and the spectral analyzes made by physicists, analogy we find in the economy elements that refer to the fervent oscillations and form "color strips" and "spectrum". To make "spectral analysis" of such a fluctuating process in terms of frequency and amplitude need a sufficient number of numerical data on the evolution of an economic process.

Colisión de aves en ventanas del Centro Universitario Victoria, Tamaulipas, México

Las colisiones de las aves con diversas construcciones humanas (e.g., ventanales de cristal) son el segundo factor de mortalidad más importante en paisajes urbanos después de la depredación por gatos. Se ha estimado que alrededor de 988 millones de aves mueren anualmente solamente en los Estados Unidos y Canadá por estos factores. Entre agosto de 2015 y septiembre de 2016 evaluamos la frecuencia de colisiones aves-ventanas en el Centro Universitario Victoria de la Universidad Autónoma de Tamaulipas en el noreste de México. Para detectar aves muertas por colisiones realizamos recorridos en busca de cadáveres dentro de una franja perimetral (tres metros de ancho) alrededor de cuatro edificios durante dos sesiones diarias de muestreo (09:00-10:00 h y 16:00- 17:00 h). Identificamos 21 aves en el suelo de 16 especies, de éstas el 50% de las especies fueron residentes y del total de colisiones 16 fueron fatales. Las especies con mayor incidencia fueron la paloma ala blanca (Zenaida asiatica) con cuatro individuos y el colibrí pico ancho (Cynanthus latirostris) con tres. Durante el muestreo también detectamos cinco especies de aves residentes con conducta agonística contra su reflejo en las ventanas con vidrio reflejante de los edificios del campus universitario. Proponemos algunas medidas para mitigar el número de colisiones de aves en el CUV (e.g., colocación de bandas de colores en las ventanas). Las especies que colisionaron representaron el 5.2% de las especies descritas para el municipio de Victoria. Determinamos mayor frecuencia de colisión en los edificios con vidrios reflejantes. Es necesario seguir desarrollando más estudios de colisiones de aves usando metodologías sistemáticas, que incluyan puntos de conteo simultáneos para considerar la prevalencia de las especies en el sitio de estudio con el fin de documentar el impacto de la urbanización en las poblaciones y comunidades de aves en diferentes centros y paisajes urbanos de México. La determinación de los factores que más influyen en las tasas de colisión de aves-ventanas ayudará en el desarrollo de acciones efectivas de manejo para reducir las colisiones en diferentes escalas espaciales y temporales.

Process severity affects texture and color of potato strips baked in pilot-scale infrared Radiant Wall Oven

Frozen par-fried potato strips were baked in an infrared radiant wall oven (RWO) at temperatures of 290–365 °C with different processing times to reduce fat content of the final product in contrast to deep fat fried strips. Product characteristics in terms of cutting force, puncture force, lightness, chroma, hue, moisture and fat content of the RWO-baked potato strips were measured and compared to that of deep-fat fried samples (177 °C for 3 min). Instrumental and sensory assessment of the texture of the potato strips indicated that RWO-baked potato strips at 365 °C for 6.5 min had similar texture as deep-fat fried potato strips, yet contained 72% less fat. However, those potato strips were lighter and less brown in color, and had 18% more moisture than the fried counterparts. RWO processing, as a surface treatment, achieved dramatic fat reduction because the potato strips were not submerged into oil. Increase in the severity of the RWO processing resulted in potato strips with higher cutting force, puncture force, darker and more brown color and lower moisture content.

Recycling of colored office paper. Part II: Post-bleaching with formamidine sulfinic acid and hydrogen peroxide

In this study, the optimization of formamidine sulfinic acid (FAS) and hydrogen peroxide (P) bleaching stages of pre-bleached blue, red, yellow, green, and mixed colored office papers was investigated. The FAS was performed as a strong color stripping reagent on blue and green colored samples. However, due to reduced amine compounds FAS was not found to be effective on the red colored samples. In contrast, effective results were obtained with hydrogen peroxide on the red and yellow colored samples. These results showed that the two reagents must be used together in a sequence. Therefore, in this study, FASP and PFAS bleaching sequences were also investigated and the optical properties (absorbance (k/s) spectra, CIE L*a*b* color values, and ISO brightness) of these sequences were compared. The color differences (CIE ΔE) of FASP and PFAS bleaching sequences of the mixed colored samples were calculated as 18.2% and 16.1%, respectively. The FASP bleaching sequence was determined to be more effective than the PFAS sequence for the bleaching of all samples. As a result, this study showed that FAS, a strong reducing agent, and hydrogen peroxide, an effective oxidative decolorizer, can be used together to obtain white writing papers from waste direct dye colored office papers.

Electrochemical stripping of cotton fabrics dyed with Reactive Black 5 in water and wastewater

Cotton fabrics dyed with Reactive Black 5 (RB5) was electrochemically stripped using Ti/TiO2-RuO2-IrO2 anode in water, pyridine and phenol solution. The results showed that RB5 dye could be easily stripped from the surface of cotton fabrics through the cleavage of chromophoric group (NN) under the attack of hydroxyl radicals (OH) and active chlorines generated in situ. Efficient stripping performance could be obtained in water and pyridine solution, whilst the stripping percent was not obviously affected by pyridine concentration and layers of dyed cotton fabrics. Whereas, phenol existing in water slowed the stripping rate due to the competition between the stripping of RB5 dye and the degradation of phenol. In the case of multi-layer dyed cotton fabrics, the stripping performance of the inner layer is superior to that of the outer layer owing to that the cotton fabrics hinder the diffusion of active chlorines and OH. The FTIR analysis of stripped cotton fabrics showed that the effect of electrochemical process and the existence of pollutant in water on the stripped cotton fabrics could be negligible. Electrochemical oxidation could also successfully strip various dyes from waste cotton fabrics in the investigated stripping solutions. Therefore, electrochemical oxidation provides an environmentally friendly alternative for color stripping of dyed cotton fabrics. The removal of dye from cotton fabrics and the degradation of pollutant in water could occur simultaneously, implying that wastewater containing chloride ions may replace the fresh water as stripping solution.

Smartphone-Based Point-of-Care Urinalysis Under Variable Illumination.

Urine tests are performed by using an off-the-shelf reference sheet to compare the color of test strips. However, the tabular representation is difficult to use and more prone to visual errors, especially when the reference color-swatches to be compared are spatially apart. Thus, making it is difficult to distinguish between the subtle differences of shades on the reagent pads. This manuscript represents a new arrangement of reference arrays for urine test strips (urinalysis). Reference color swatches are grouped in a doughnut chart, surrounding each reagent pad on the strip. The urine test can be evaluated using naked eye by referring to the strip with no additional sheet necessary. Along with this new strip, an algorithm for smartphone based application is also proposed as an alternative to deliver diagnostic results. The proposed colorimetric detection method evaluates the captured image of the strip, under various color spaces and evaluates ten different tests for urine. Thus, the proposed system can deliver results on the spot using both naked eye and smartphone. The proposed scheme delivered accurate results under various environmental illumination conditions without any calibration requirements, exhibiting performances suitable for real-life applications and an ease for a common user.

Nanomolar Level Detection of Uric Acid in Blood Serum and Pest-Infested Grain Samples by an Amphiphilic Probe.

A pyrene based amphiphilic receptor has been utilized in the nanomolar detection of uric acid at physiological pH in water. The compound shows a unique concentration-dependent modulation in optical response toward uric acid. In intramolecular/static excimer form (low concentration range), it displays a ratiometric response, while a "turn-off" sensing is observed specifically in the presence of intermolecular/dynamic excimer (high concentration range). The present protocol is then employed for the estimation of uric acid in blood serum samples of healthy individuals. Bland-Altman analysis in comparison to clinically approved uricase assay indicated the high accuracy of the present method. Additionally, the extent of insect infestation in stored grain samples was determined by measuring the uric acid content of their aqueous extracts. Low-cost color strips were developed for on-site detection of uric acid without involving any sophisticated instrument or trained personnel.

Photocatalitic stripping of fixed Reactive Red X-3B dye from cotton with nano-TiO2/UV system

A novel, green and Ecofriendly method for photocatalitic stripping of fixed Reactive Red X-3B dye on cotton substrate was developed at the first time by employing a nano-TiO2/UV system in a self-built photoreactor. The effects of photocatalitic stripping parameters such as the initial pH value of working solution, temperature and stripping duration, on color stripping efficiency and fabric tensile strength were investigated. Moreover, the photocatalitic stripping of the fixed reactive dye on cotton substrate in the nano-TiO2/UV system was further explored by Attenuated total reflection-Fourier transform infrared spectrometry (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM). The results show that the fixed Reactive Red X-3B dye on cotton could be photocatalitically stripped or decolorized efficiently by employing the nano-TiO2/UV system with a dipped stripping manner in which the substrate was immersed into working solution. The tested stripping parameters of temperature and treatment duration presented notably positive effects on the color stripping efficiency, while an inappropriate control of all the parameters could result in a deterioration of the tensile strength of the substrate. Furthermore, a heterogeneous photocatalitic color stripping mechanism was also supposed for the fixed Reactive dye molecules on cotton substrate in nano-TiO2/UV system with the dipped stripping manner.

Sage Russet: a New High Yielding Russet Potato Variety with Cold-Sweetening Resistance, High Vitamin C and Protein Contents and Excellent Fresh Pack and Processing Potential

Sage Russet was released in 2009 by Oregon State University, in cooperation with the USDA-ARS and the Agricultural Experiment Stations of Idaho and Washington. It is a product of the Northwest Potato Variety (Tri-State) Development Program. Sage Russet has a medium-early maturity and produces long, somewhat flattened tubers with medium russeting of the skin. Total yields of Sage Russet are similar to those of Russet Burbank and Ranger Russet, but are significantly higher than those of Russet Norkotah. Sage Russet has significantly higher U.S. No.1 yields than Russet Burbank, Russet Norkotah, and Ranger Russet. It can be grown as an early or late crop with high U.S. No.1 yields and minimal internal defects. It achieved very high merit scores in processing and fresh market in Western Regional trials and can be considered for both markets. Sage Russet has a medium to high fertility requirements with high nitrogen use efficiency and medium storage capability. Sage Russet has moderate specific gravity and produces lighter fry color than the industry standard varieties. The color of fried strips following tuber storage at 4.4 °C and 7.2 °C is significantly lighter for Sage Russet than the control varieties, indicating good cold sweetening resistance. Chemical analyses have shown that Sage Russet has higher protein and vitamin C content than control varieties. Sage Russet is moderately resistant to early dying, early blight, and common scab, is resistant to tuber late blight, but susceptible to Fusarium wilt and is prone to shatter bruise.

Fluorescent Strips of Electrospun Fibers for Ratiometric Sensing of Serum Heparin and Urine Trypsin

"Turn-on" or "turn-off" probes remain challenges in the establishment of sensitive, easily operated, and reliable methods for in situ monitoring bioactive substances. In the current study, electrospun fibrous strips are designed to provide straightforward observations of ratiometric color changes with the naked eye in the presence of serum heparin or urine trypsin. A tetraphenylethene (TPE) derivative is constructed and along with phloxine B is grafted on fibers, followed by protamine adsorption to induce static quenching of phloxine B and aggregation-induced emission of the TPE derivative. The presence of heparin or trypsin removes protamine to restore the fluorescence of phloxine B at 574 nm (I574) and relieve the emission of the TPE derivative at 472 nm (I472). The grafting densities of phloxine B and the TPE derivative are essential to achieve the optimal fluorescence-intensity ratio of I574/I472 for the ratiometric detection of heparin and trypsin. Under illumination by an ultraviolet lamp, the fibrous mats turn from cyan to green in the presence of heparin at 0.4 U/mL and to a bright yellow at 0.8 U/mL, which is feasible in sensing serum heparin levels during postoperative and long-term care of patients after cardiovascular surgery. The protamine digestion results in similar color transitions with increasing trypsin levels up to 8 μg/mL, indicating the potential for monitoring urine trypsin levels of pancreas transplant patients. The color strips based on the ratiometric fluorescent response indicate advantages in lowering the detection limit and improving the accuracy and reproducibility, bearing great potential for a real-time and naked-eye detection of bioactive substances as self-test devices.

Smartphone-based colorimetric detection via machine learning.

We report the application of machine learning to smartphone-based colorimetric detection of pH values. The strip images were used as the training set for Least Squares-Support Vector Machine (LS-SVM) classifier algorithms that were able to successfully classify the distinct pH values. The difference in the obtained image formats was found not to significantly affect the performance of the proposed machine learning approach. Moreover, the influence of the illumination conditions on the perceived color of pH strips was investigated and further experiments were conducted to study the effect of color change on the learning model. Non-integer pH levels are identified as their nearest integer pH values, whereas the test results for integer pH levels using JPEG, RAW and RAW-corrected image formats captured under different lighting conditions lead to perfect classification accuracy, sensitivity and specificity, which proves that colorimetric detection using machine learning based systems is able to adapt to various experimental conditions and is a great candidate for smartphone-based sensing in paper-based colorimetric assays.