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A most common problem encountered in radiosterilization of solid drugs is discoloration or yellowing. By pharmacopoeia method, discoloration can be assessed by measuring absorbance of solutions of irradiated solid samples at 450 nm. We propose to evaluate discoloration of solid samples directly by recording their diffuse reflectance spectra. Furthe...
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... subscript n refers to the tristimulus values of the perfect diffuser for the given illuminant and standard observer. The exponent 1/3 in equation for tristimulus values greater than 0.008856 provides the nonlinearity mentioned earlier. For values less than 0.008856, linearity piece is kept so as to avoid difficulty during conversion of Lab to XYZ Also, L * designates lightness which is equivalent to luminance like aspect of reflective color. The chrominance is described by two variables a * and b * representing red vs. green and yellow vs. blue axes, respectively. The spatial representation of CIE Lab color space is shown in Fig. 3. From CIE Lab values of unirradiated and irradiated samples color difference ( $ E Ã ab ) was calculated using following equation (13) The subscripts 1 and 2 refer to the irradiated and unirradiated samples, respectively. The $ E Ã ab value is useful for quantitation of color difference and for defining color tolerance limit. The dominant wavelength of a color correlates in an approximate way with what would be called as the hue of the color as observed under everyday conditions. It can also be defined as the wavelength of the spectrum band, which, when mixed with some specified achromatic stimulus, matches the given color. The derivation of dominant wavelength form the chromaticity coordinate is carried out by drawing a straight line through the point representing the achromatic color D65 and the point S representing the color to be evaluated, and this line is produced in the direction D65 to S to intersect the spectrum locus. The wavelength of the intersection is the required dominant wavelength ( λ d ) of the given color as depicted in Fig. 4. The excitation purity of any color possessing a dominant wavelength is an exactly defined ratio of distances in the chromaticity diagram indicating how far the given color is displaced from the achromatic color toward the spectrum color (Fig. 4). Excitation purity is the degree of saturation relative to the most concentrated form. The excitation purity calculated from trichromatic values is defined by The yellowness index shows a degree where the hue leaves white or achromatic color toward yellow. If it takes a negative value, it moves in the blue direction. The yellowness index for 2° observer and D65 illuminant is calculated by following ...
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Most of the studies on sunlight-induced pigmentation of skin are mainly focused on ultraviolet (UV) radiation-induced pigmentation and ways to prevent it. Recent studies have shown that the visible component of sunlight can also cause significant skin pigmentation. In the current study, the extent of pigmentation induced by UV and visible regions o...
Citations
... The coordinate L* stands for lightness, the a* value indicates the red-green component of color, and the yellow and blue components are represented by the b* value. The color change is evaluated using the total color difference ∆ ab * , which considers both the lightness difference and the difference in the chromatic plane (Singh et al. 2009). ...
This study focuses on the effectiveness of a new substance in stabilizing paper information carriers - hydrotalcite applied to the paper in a partially polar environment. The effect of modification on the stabilization of paper during accelerated aging was investigated by measuring chemical (surface pH, rate of glycosidic bond cleavage), mechanical (coefficient of the relative increase of the lifetime for folding endurance), optical (colorimetry - CIE L*a*b*), and spectral (FTIR) properties. Three types of hydrotalcites differing in composition, particle size, and preparation conditions, were tested and compared. After the modification, all the properties of acidic test papers improved. The most promising type of hydrotalcite was prepared under the nucleation action of citric acid. The atomic ratio of Mg2+ to Al3+ of this hydrotalcite was equal to 5. Modification by this hydrotalcite led to an increase in surface pH by 1.3 to 2.7 units.
... The coordinate L* stands for brightness, the a* value indicates the red-green component of color, and the yellow and blue components are represented by the b* value. The color change is evaluated using the total color difference ∆ ab * , which takes into account both the lightness difference and the difference in the chromatic plane (Singh et al. 2009). As a result of aging, the L* coordinate decreases, at the same time the a* and b* coordinates also change. ...
Stabilization and deacidification of paper information carriers is still a highly discussed topic. It is very important to continue in searching for new, more effective, and affordable methods of paper stabilization because none of the currently known processes is ideal. This study focuses on the effectiveness of a new substance in stabilizing paper information carriers - hydrotalcite, applied to the paper in a partially polar environment. The effect of modification on the stabilization of paper during accelerated aging was investigated by measuring chemical (surface pH, rate of glycosidic bond cleavage), mechanical (coefficient of the relative increase of the lifetime for folding endurance), optical (colorimetry - CIE L*a*b*), and spectral (FTIR) properties. Three types of hydrotalcites differing in composition, particle size, and preparation conditions, were tested and compared. After the modification, all the properties of acidic test papers improved. The most promising type of hydrotalcite was prepared under nucleation action of citric acid. The atomic ratio of Mg2+ to Al3+ of this hydrotalcite was equal to 5. Modification by this hydrotalcite led to an increase in surface pH by 1.3 to 2.7 units.
... Para evaluar el color, se obtiene el Delta-E con la calculadora Cie94. Para comprender los ejes en las tres dimensiones del color con las coordenadas X, Y, Z, es necesario indicar lo mencionado por Singh et al. (2009) ...
La búsqueda de alternativas más sostenibles y menos contaminantes para la industria textil ha llevado a explorar el uso de pigmentos naturales y orgánicos para el teñido de tejidos. El objetivo de esta investigación es analizar la formación de nanopigmentos con extracto de achiote para su uso en el teñido de algodón 100%. El método científico utilizado es el experimental y la observación, además se utiliza varias técnicas cualitativas y para la extracción pasa por la maceración dinámica, rotavapor, separación con hidróxidos y de los extractos se toma una muestra al azar y por conveniencia se realiza la mezcla homogénea con la nanoarcilla donde se obtuvieron los nanopigmentos mediante un proceso de síntesis en el cual se utilizó arcilla hidratada de Trimethyl Estearil Ammonium como soporte, y se insertaron moléculas orgánicas de achiote. Luego se procede a Tinturar varias muestras de algodón mediante receta prevista, para posterior realizar el lavado. Los nanopigmentos obtenidos se caracterizaron mediante diversas técnicas, como microscopía electrónica de barrido SEM y con el espectrofotómetro se evalúa la solidez del color al lavado y mediante la calculadora Cie94 se obtiene el Delta-E. Entre los hallazgos SEM la muestra Co_9 Trimethyl + P tiene una valoración (2)= presencia de NP, con un color anaranjado rojizo ladrillo con (∆E = 58.61) lo contrario sucede con la muestra Co_5 Trimethyl + R, se valora como (1) = reducida presencia NC, tiene un color: Amarillento pálido muy débil (∆E = 3.46) y se evaluó la solidez del colorante y también se valora el frote en seco y húmedo con la escala de grises. Asimismo, se obtiene el rendimiento promedio de 9.09%, obteniéndose resultados en términos de solidez 1 y cambio de color 5 en los tejidos teñidos con pigmento solido contrario a la baja solidez en los tejidos con colorante líquido. Por ello se concluye que los nanopigmentos de achiote obtenidos son una alternativa viable y sostenible para el teñido de textiles y su aplicación en la industria textil.
... Reproduced with permission. [160] Copyright 2009, Springer Nature. ...
The use of smartphone‐based analysis systems has been increasing over the past few decades. Among the important reasons for its popularity are its ubiquity, increasing computing power, relatively low cost, and capability to acquire and process data simultaneously in a point‐of‐need fashion. Furthermore, smartphones are equipped with various sensors, especially a complementary metal–oxide–semiconductor (CMOS) sensor. The high sensitivity of the CMOS sensor allows smartphones to be used as a colorimeter, fluorimeter, and spectrometer, constituting the essential part of point‐of‐care testing contributing to E‐health and beyond. However, despite its myriads of merits, smartphone‐based diagnostic devices still face many challenges, including high susceptibility to illumination conditions, difficulty in adapter uniformization, low interphone repeatability, and et al. These problems may hinder smartphone‐enabled diagnosis from passing the FDA regulations of medical devices. This review discusses the design and application of current smartphone‐based diagnostic devices and highlights challenges associated with existent methods and perspectives on how to deal with those challenges from engineering aspects on constant color signal acquisition, including smartphone adapter design, color space transformation, machine learning classification, and color correction. This review discusses the design and application of current smartphone‐based diagnostic devices and highlights challenges associated with existent methods and perspectives on how to deal with those challenges from engineering aspects on the constant color signal acquisition, including smartphone adapter design, color space transformation, machine learning classification, and color correction.
... In other interpretations, DW represents the principal wavelength of the colour, i.e. DW correlates with the colour's hue [40]. In general, the larvae processing resulted in fluctuations in DW around the steady-state value of 577 nm (Table 3), pointing to the presence of yellow pigments. ...
... Therefore, it can be concluded that these parameters are not suitable for mealworms differentiation. The excitation purity of any colour possessing a DW is an exactly defined ratio of distances in the chromaticity diagram indicating how far the given colour is displayed from the achromatic colour toward the spectrum colour [40]. Values of excitation purity differed significantly from each other (p < 0.05). ...
The colour of processed mealworms is an important attribute that affects their utilization in food industry. Totally 15 colour and related spectral variables of powders prepared from differently processed (oven drying, freeze-drying, microwave drying, blanching, and their combinations) mealworms larvae (Tenebrio molitor) were evaluated by UV/Vis spectroscopy and multivariate analysis. The results obtained confirmed deterioration of mealworms colour after processing. In general, processing led to a decrease of lightness (L*), hue angle (h°), whiteness-blue-reflectance, whiteness index (WI) and tinting index coinciding with an increase in the yellowness index (YI), redness (a*), browning index (BI) and total colour difference (ΔE) compared to untreated larvae. Oven drying at higher temperature caused the pronounced darkening described by the highest BI and ΔE values (ΔE = 28.54 ± 0.37, BI = 53.78 ± 0.31). On the other hand, freeze-drying was the most suitable colour protection method. Based on lower BI and ΔE values, the combination of 3 min blanching with microwave and oven drying can be recommended as a proper alternative to freeze-drying. Most of the colour descriptors of processed larvae differed significantly from each other (p < 0.05). Absolute discrimination of processed mealworms larvae was achieved through principal component analysis and discriminant analysis. Values of L*, yellowness (b*), chroma, BI, ΔE and whiteness-blue-reflectance were identified as the most discriminating. Moreover, mutual correlations of monitored parameters, e.g. tinting and WI; a*, b* and C* values; or L* and ΔE were revealed by principal component factoring.
... Distribution of the colors in the CIE Lab system[13] ...
The aim of this paper is to analyze the effect of replacing part of wheat flour (4, 8, 16, 24 and 32% for cookies and 4, 6, 8 and 10% for sponge cake) and to measure influence on the color of the cookies and the sponge cake with apple skin powder and grape pomace powder, respectively. The cookies were produced according to the AACC 10-50D method with some modifications, and the sponge cake was produced according to the method presented by Velioğlu et al., 2017 with some modifications. Digital image analysis and colorimeter were used to determine the colour change of the samples. Results show that by increasing food by-products (apple skin powder and grape pomace powder), the colour difference between the control sample and other samples was bigger. The colour of the sample measured by digital image analysis covers the entire sample and is more representative and more objective regarding colour measurement.
... Several studies have reported the chemical stability of pharmaceutical drugs or antibiotics after irradiation. [20,21] However, there are no reports on the effects of ionizing radiation on biological activities (antimicrobial and cytotoxicity) of pharmaceuticals. Therefore, in this study, value addition of E‑beam radiation on biological properties of mouth rinses was evaluated. ...
... This can be manifested by change in color or precipitation or sedimentation of the irradiated substance. [20] A gradual discoloration in mouth rinses irradiated from 250 Gy to 750 Gy and a complete discoloration at 1000 Gy of irradiation indicated the changes in chemical properties of mouth rinses upon E‑beam radiation [Figure 3]. However, there were no changes in pH, as it was observed to be 6 for CP and 4 for LS before and after irradiation. ...
Background: Oral health diseases are common in all regions of the world. Mouth rinses are widely used generally by population as a port of daily oral care regimen. In addition to antimicrobial activity, mouth rinses possess certain cytotoxic effects. Electron-beam (E-beam) radiation is a form of ionizing energy known to induce structural, physical, and chemical changes in irradiated products. In this study, the modulatory effects of E-beam in irradiated mouth rinses were evaluated for its biological activities.
Materials and Methods: The antimicrobial activities of nonirradiated and irradiated mouth rinses were evaluated for its antimicrobial and antibiofilm activities against oral pathogens, Enterococcus faecalis, Streptococcus mutans, Staphylococcus aureus, and Candida albicans. The antimicrobial activity was evaluated by disc diffusion method and antibiofilm activity was evaluated by O'Toole method. The cytotoxicity was evaluated against human gingival fibroblast (HGF) cells by 3-(4, 5 Dimethythiazol-yl)-2,5-Diphenyl-tetrazolium bromide assay.
Results: Colgate Plax (CP) exhibited the antimicrobial activity against the tested pathogens, and a significant (P< 0.05) increase was observed against S. aureus at 750 Gy irradiation. Further, CP significantly (P< 0.05) suppressed S. mutans, S. aureus, and C. albicans biofilm. Listerine (LS) inhibited S. mutans and C. albicans biofilm. Whereas irradiated CP and LS significantly (P< 0.05) suppressed the biofilm formed by oral pathogens. The suppression of biofilm by irradiated mouth rinses was dose- and species-dependent. There was no significant (P > 0.05) difference in the cytotoxicity of irradiated and nonirradiated mouth rinses on HGF cells. However, an increased percentage viability of HGF cells was observed by mouth rinses irradiated at 750 Gy.xs
Conclusion: The E-beam irradiation enhanced the antibiofilm activity of mouth rinses without modifying the cytotoxicity.
... The main concern of using e-beam radiation is the degradation of the native compound leading to formation of new radiolytic intermediate or free radicals, which manifested by change in color of the irradiated substance [19]. The unchanged color of irrigants and nonappearance of sediments or precipitation following the exposure to e-beam radiation on day1 and after 180 d storage at 4 o C illustrates the absence of radiolytic compounds in irradiated dental irrigants. ...
... We found that e-beam irradiation increased the antimicrobial activity of 1.25% NaOCl and 1% CHX on E. faecalis and of 1.25% NaOCl, 2.5% NaOCl, 1% CHX and 2% CHX on S. aureus. In contrary, the previous studies conducted on antibiotics did not show any significant changes in their biological property after exposure to gamma irradiation [1,19]. This difference might be either due to the state of the substance used for radiation or the source of radiation. ...
The electron beam (e-beam) radiation is considered as an effective means of sterilization of healthcare products as well as to induce the structural changes in the pharmaceutical agents/drug molecules. In addition to structural changes of pharmaceutical it also induces the formation of low molecular weight compounds with altered microbiological, physicochemical and toxicological properties. Among the several known medicaments, sodium hypochlorite (NaOCl) and chlorhexidine digluconate (CHX) are used as irrigants in dentistry to kill the pathogenic microorganisms like Enterococcus faecalis, Staphylococcus aureus, Streptococcus mutans and Candida albicans inhabiting the oral cavity.
The aim of this study was to evaluate the antimicrobial activity and stability of e-beam irradiated dental irrigants, NaOCl and CHX.
Two dental irrigants NaOCl (1.25% and 2.5%) and CHX (1% and 2%) were exposed to various doses of e-beam radiation. The antimicrobial activities of e-beam irradiated irrigants were compared with the non-irradiated (control) irrigants against E. faecalis, S. aureus, S. mutans and C. albicans by disc diffusion method. Following the storage, physico-chemical properties of the irrigants were recorded and the cytotoxic effect was evaluated on human gingival fibroblast cells.
The irrigants, 1.25% NaOCl and 1% CHX showed significantly increased antimicrobial activity against both E. faecalis, (16+0.0) and S. aureus (25+0.0) after irradiation with 1 kGy e-beam. Whereas, 2.5% NaOCl and 2% CHX showed slightly increased antimicrobial activity only against S. aureus (28+0.0). The significant difference was noticed in the antimicrobial activity and cytotoxicity of irradiated and non-irradiated irrigants following the storage for 180 d at 4(0)C.
The e-beam irradiation increased the antimicrobial activity of irrigants without altering the biocompatibility.
... On fluoroquinolone and cephalosporin antibiotics, followed by various doses of radiation sterilisation process, the optical and colorimetric parameters were examined; all of the flurokinolon antibiotics were radiation resistant and only Cefdinir was found to be resistant from the cephalosporins (79). ...
Nowadays, sterilization process is used for the benefit of humans in different areas of daily life. This includes the sterilisation of medical supplies and pharmaceuticals, in particular agent and auxiliary materials, decontamination of medical equipment, and decontamination of industry, for example drug-herb and vegetable products are used in broad areas. Gamma irradiation sterilisation methods stand out, with numerous advantages. Day by day, those who use this method are applying them in more fields, and the product has gained increasingly widespread use. In fact, according to official authorities in many countries, it has been accepted as a method and has become routine since it was introduced. With regard to pharmaceutical products, gamma irradiation sterilisation has been used and records show the continuous development of the method for sterilisation. Recent studies have focused on many different pharmaceutical products, active and auxiliary substances, active ingredients in drugs, and new drug delivery systems, and discuss the effects of radiation sterilisation on the work. Especially after irradiation, which is much used in the control of analytical studies and reviews, and sterility controls over time, these methods are developing rapidly. The investigation into the use of gamma radiation continues; a new development began to attract attention: the use of e-beam irradiation sterilisation. Increased attention in the developments and studies of this subject, with focus on gamma radiation sterilisation of pharmaceuticals, will become more important in the future.
Aims
The present study aimed to evaluate the antibacterial effectiveness of newly formulated root canal irrigants derived from natural sources. In particular, this study investigated how these irrigants’ antimicrobial properties were affected by gamma radiation activation.
Materials and Methods
Fifty-three single-rooted extracted human teeth with straight canals were selected, fully prepared, and sterilized. The roots were then infected with Escherichia coli, Enterococcus faecalis, and Candida albicans for 21 days at 37°C. Based on the irrigating solution utilized, the roots were divided into seven groups: Group I: chitosan irrigant, Group II: chitosan irrigant gamma irradiated, Group III: curcumin irrigant, Group IV: curcumin irrigant gamma irradiated, Group V: sodium hypochlorite (NaOCl) 5% irrigant, Group VI: positive control (infected roots without treatment), and Group VII: negative control (uncontaminated roots). After cleaning and shaping, microbiological sampling was performed. The samples were then transferred to sterile centrifuge tubes containing 1 mL of saline to determine the microbial growth. Colony-forming unit counts were employed for assessing the antimicrobial action. Statistical analysis was conducted to compare the percentage reduction in the microbial count from the initial count.
Results
Group V and Group IV showed significantly higher values in microbial reduction than Group III and Group I. In addition, the results showed that Group II and Group III have significantly higher values than Group I.
Conclusion
Natural irrigating solutions exposed to gamma radiation exhibited promising antimicrobial activity that is comparable to that of NaOCl and may be used as effective antimicrobial agents in endodontic treatment.
