NBS Units Research Articles

Designing iron‐ethyl cellulose microparticles to prevent unwanted color changes during iron fortification of milk tea

AbstractIron deficiency affects an estimated 1.62 billion individuals worldwide, while Asia and Africa bearing the highest burden. The widespread consumption, unique sensory properties and cultural significance of tea make it an appealing avenue for iron fortification. Obtaining microparticles for food fortification with acceptable organoleptic properties is key for consumer acceptability. Microcapsules were prepared with Aquacoat and various iron salts. The experiments were designed to understand the effect of formulation variables, i.e. type of iron salt, ratio of iron‐to‐coating, temperature and flow rate of the process. The iron compound significantly impacted yield, particle formation, and size distribution (5‐15 μm). Post treatment by curing at specified relative humidity and temperature improved the colour in milk tea with ΔE reduced from 7 to 2 in NBS units. Microparticles from FeCl3 exhibited superior morphology and colour‐masking efficacy, inhibiting iron‐polyphenol interaction in tea and show promise as iron fortificants for milky black tea.Practical applicationsMicroencapsulation is a highly effective technique for encapsulating active iron cores within inert coating materials, ensuring the desired chemical and physical properties. Using spray drying, we can produce small and uniformly sized particles ranging from 1 to 20 μm. This can easily be utilized for fortification of beverage like hot tea/coffee or similar products. The success of the current process is evaluated based on several key factors, including process yield, encapsulation efficiency, and sensory properties of fortified tea.

Color stability of aligner materials on exposure to indigenous food products: An in-vitro study.

In the recent day, there has been an exponential growth in the usage of clear aligners for orthodontic treatment. As with any removable appliance, the compliance of patients to remove it during ingestion of food is, at times, poor. Thus, the stability of the clear aligner to be "clear" becomes questionable. This in-vitro study examined how the clear aligners changed colour on exposure to various indigenous food products used in everyday life. Aligners from 5 different companies (K Line, Clearbite Aligners, The Aligner Company, iAligners and MaxDent CA Digital) were exposed for 12 hours and 24 hours to various indigenous substances (tea, green tea, coffee, turmeric, saffron and Kashmiri red chili powder) and a control solution (distilled water) in-vitro. The color change was assessed with the help of VITA Easyshade compact colorimeter based on Commission Internationale de I'Eclairage L*a*b* color system. Values were then modified to NBS units for clinical relevance. The hue of the transparent aligners was noticed to change in a statistically meaningful way when exposed to turmeric, saffron, Kashmiri red chili powder and coffee in decreasing order and mild color change in tea and green tea at both 12 hours and 24 hours intervals. Aligners are prone to color change when exposed to indigenous foods that contain staining properties.

Color changes in bulk-fill resin composites as a result of visible light-curing.

We evaluated twelve commercially available bulk-fill resin composites to determine the colorimetric changes that occurred as a result of the photo-polymerization reaction. Samples of the resin composites were prepared as disks 8 mm in diameter and 3 mm in thickness. A colorimeter was used to measure the color of samples on a black background before and after the polymerization processed had been initiated. As results, each of the photo-initiated bulk-fill resin composites tested except for Beautifil Bulk A showed a significant color difference more than that of conventional resin composites. Bulk Base Flow became darker, whereas Beautifil Bulk Flow became clearly lighter. All resin composites except for Bulk Base Flow became less yellow. Thus, Beautifil Bulk A exhibited the least color change among all the bulk-fill resin composites. However, this color change showed a marked change (NBS units) as observed by the human naked eye.

Influence of Different Beverages on the Color Stability of Nanocomposite Denture Base Materials.

Background The effect of beverages on nanocomposite denture base materials is neglected. Therefore, this study aimed to investigate the influence of different beverages (coffee, tea, cola, and mineral water) on the color stability of nanoparticles-modified denture base materials (DBMs). Materials and Methods A total of 280 specimens (n = 10/group) were prepared from heat-polymerized acrylic resin modified with different concentrations (3% and 7%) of zirconium dioxide (nano-ZrO2), titanium dioxide (nano-TiO2), and silicon dioxide (nano-SiO2) nanoparticles, while 0% was taken as a control. Color change (∆E) of the specimens was evaluated after simulating 6-month immersion time in four commonly used beverages, coffee, tea, cola, and mineral water, as experimental groups. Color stability was measured using a spectrophotometer, and then values were converted to National Bureau of Standards units (NBS units). The one-way ANOVA test was applied to compare color change (ΔE) results followed by Bonferroni's post hoc test (α = 0.05). Results The results showed that the heat-polymerized acrylic resin modified with different types of nanoparticles showed lower color changes after being immersed in beverage solutions compared to the unmodified group (P < 0.001), so the color stability of heat-polymerized acrylic resin was significantly enhanced by the addition of several nanoparticles; nano-ZrO2 showed the lowest ΔE followed by nano-TiO2 and then nano-SiO2. Regardless of the filler type, 3% concentration showed lower mean ΔE than 7% concentration. Regarding the beverage solutions, the greatest color change was found in the coffee group followed by tea and cola, while water showed the least changes. Conclusion Modification of heat-polymerized acrylic resin with certain amounts of nano-ZrO2, nano-TiO2, and nano-SiO2 may be useful in improving color stability.

Comparison of color stability of different coated esthetic orthodontic archwires using spectrocolorimeter – An invitro study

Aim: The aim of this study was to evaluate and compare the colour stability of three different esthetic archwires (rhodium, teflon and epoxy coated) immersed in three different staining solutions (tea, coffee and artificial aerated orange drink) at different time intervals (0, 7, 14, 21, 45 day) using spectrocolorimeter and also to determine the most chromogenic agent. Materials and Methods: A total of 54 esthetic coated archwires (rhodium, teflon and epoxy) were evaluated. They were divided into 3 groups (archwires) with each group having 3 subgroups (staining solutions) and six samples in each sub group. The baseline value (T0) was measured before the samples were immersed in the staining solutions. The samples were immersed in the staining solution for 3 hours a day for 45 days. The ?E values were recorded on 7, 14, 21 and 45 day using spectrocolorimeter. Using these values NBS units were calculated. The experimental data were analyzed using descriptive statistics, analysis of variance, and post hoc Bonferroni test. Results: It was found that teflon coated esthetic archwires were the least colour stable when compared with rhodium and epoxy coated esthetic archwires. Artificial aerated orange drink caused higher ?E* values than tea and coffee. The ?E* value increases as the time interval increases. Conclusions: All esthetic archwires evaluated in the present study were stained the most by an artificial aerated orange drink in comparison with coffee and tea. The overall study outcome indicates that archwires coated with epoxy resin are more advisable for patients because of their colour stability. Keywords : Colour stability, Esthetic archwires, Staining solutions, Spectrocolorimeter.

Sensitive detection of DMSO/DMF in water, human urine and blood plasma using novel 1,8-naphthalimide-based amphiphilic spectroscopic probes

Dimethyl sulfoxide (DMSO) and dimethylformamide (DMF) are industrial toxins that need to be sensed. We synthesized 1,8-naphthalimide-m-benzenesulfonamide (NBS)-bearing probes (1–5) with different pendant chains for sensitive detection of DMSO and DMF. These probes exhibited aggregation-induced emission enhancement with increasing water concentration in ethanol. Among these, monopod probes with a single NBS unit (1–4) selectively showed large fluorescence quenching upon addition of DMSO/DMF in water. Based on this result, we prepared two water-soluble probes (8 and 9) bearing the NBS unit. These probes displayed enhanced sensitivity in detecting DMSO/DMF in water compared to probe 1, showing an extraordinary low LOD of 0.0025% for DMSO and DMF detection in water. Probe 9 was similarly effective at sensitively sensing DMSO/DMF when tap or lake water was used as the medium, and the LOD of this probe was 0.05% when biological fluids such as diluted human urine and blood plasma were used instead of water. According to DLS, FE-SEM and zeta potential studies as well as DFT calculations, disaggregation of probe aggregates and electron transfer from the photo-excited probe to DMSO/DMF are likely both responsible for the high selectivity and sensitivity of this probe in detecting the organic solvents containing a sulfoxide/amide group.

The influence of cigarette smoke on colour stability and friction property of aesthetic orthodontic wires—In vitro study

To evaluate the colour stability and friction property of aesthetic orthodontic wires when exposed to cigarette smoke. Forty-eight samples of aesthetic orthodontic wires (0.019″×0.025″) were allocated to three experimental groups according to their brand (n=8): GAD (Aditek™); GTP (TP Orthodontics™); GRM (Rocky Mountain™) and their respective control groups (GC) (n=8). Samples were exposed to 2cycles of smoke in a hermetic chamber while GCs were stored in artificial saliva at 37°C. Colour analysis (CIEL*a*b* colour space and NBS units) was performed on 5mm wire segments with the Vita Easyshade Compact spectrophotometer. The friction analysis was performed in a universal test machine, in segments of 5cm wires tied to ceramic brackets with maximum values recorded in N/cm. The comparison between groups was performed with the ANOVA/Tukey test (a=0.05) and the effect of the time evaluated with ANOVA-MR with Bonferroni correction (a=0.016). GTP and GRM did not show significant colour and friction property variations and did not differ from GC during the study (P>0.05). However, GAD was significantly sensitive to colour changes (T1-T0-L*: -4.09±1.06; a*: 2.25±0.39; b*: 1.70±0, (T2-T0-L* 0.66±0.92; a*: 2.76±0.35) and friction (T2-T0: 2.07±1.00N/cm) (P<0.016). Exposure to cigarette smoke may alter the mechanical and optical properties of aesthetic orthodontic wires.

Study of ceramics color development on the basis of Nizhneuvelsky Kaolin clay

Aim: They analyzed the influence of iron-containing phases on the ceramics color development made of Kaolin clay of Nizhneuvelsky deposit. Materials and Methods: The result of the complex application of modern study methods - thermal, electron microscopic, radiographic, Mossbauer, optical - it was established that the change of kaolin clay calcination temperature from 1000°C to 1200°C leads to the increase of L* luminance from 75 to 79 NBS units (National Bureau of Standards, USA), which correlates with the analysis of Mossbauer spectra, reflecting the decrease of the strongly staining phase of hematite. The crystallization of the mullite mineral is the consequence of ceramics clarification process based on Kaolin clay with the calcination temperature increase from 1000°C to 1200°C. Results: It was found that the absorption bands in the calcined clay of the Nizhneuvelsk deposit with the wavelengths of 432 and 480 nm, baked at 1000°C, are associated with spin-forbidden transitions 6A1 (6S) →4A1,4E (4G) in Fe3+ ions that have an octahedral environment. Conclusion: It was found that Fe3+ ions could produce the absorption lines at the wavelengths of 432 and 480 nm, only being in the structure of mullite. At 1200°C, the partial amorphization of the mineral composition of clay takes place, which leads to the averaging and broadening of the absorption band in the area of 400–550 nm.

Optimal generation units start-up sequence during restoration of power system considering network reliability using bi-level optimization

During recent years power systems are operated near the nominal capacity of system equipment with low stability margin. Operation of power systems in this condition is extremelyrisky and power systems lose their stability with any intense failure of system equipment. In bulk power system, it is more critical and may cause a partial or overall blackout. The capability of black start to bring back system to a normal condition in the case of partial or overall shut down is very important in each power system. When a shutdown occurs, power plants with black start capability supply cranking power for non-black start power plants, pick up critical loads and energize required transmission lines. These actions should be done in minimum time interval to maximize system provided energy during the restoration process. Most important decision making during restoration process is the determination of start-up sequence of generation units. During the restoration process, units with black start capability (BS units) start at the beginning of the process to provide cranking power for non-black start units (NBS units). Hence the determination of NBS units is decision variable in the restoration problem. In this paper, this problem has been described as a bi-level optimization problem which in upper level determines the optimal start-up sequence of NBS units by using a Teaching-Learning Based Optimization algorithm and in lower level determines the optimal transmission path with minimum number of switching and maximum reliability between any two necessary buses using the searching path graph-based algorithm. The proposed approach has been implemented successfully on IEEE 24-bus RTS and IEEE 118-bus test systems.

Expert aspects of information technologies for evaluation of spectral characteristics of textile materials

Expert aspects of information technologies for evaluation of the spectral characteristics of textile materials are considered in the paper. The main research goal is to develop recommendations on evaluating the results of color reproduction on fabrics with different textures based on the analysis of the results, obtained using computerized evaluation systems, mathematical description and reproduction of color and solving production coloistics problems. To achieve this goal, the empirical results are analyzed, and the main task, namely, to establish an objective quantitative relationship between the fabric texture and spectral characteristics of colors, obtained with direct dyes is solved. It is found that the Gurevich-Kubelka-Munk function values increase when decreasing the thinness of fabric and weaving, which provides a higher reflection coefficient of undyed fabric, in this case, a twill weave. It is shown that color deviation definition in NBS units does not accurately reveal color discrimination. During the examination of the spectral characteristics of textile materials to meet the standards, it is recommended to assess color discrimination not only in NBS units, but also according to the hue. The considered expert aspects of information technologies for evaluation of the spectral characteristics of textile materials allow not only to improve the examination methodology, but also the technological regimes to enhance the production efficiency of textile materials.

Soak Colored Zirconia Ceramics and its Colorimetric Plate

Objective: To test specimens of soak-colored Vita In-Ceram YZ zirconia ceramics and the colorimetric data of staining solution colorimetric plate. Methods: five sets of specimens were prepared, soaking and coloring them with LL1 to LL5 staining solution for 2 min respectively. Specimens were sintered for 2 h at 1530°C, and grinded one side of the specimens to 1.5 mm in thickness. The colors of the specimens and staining solution colorimetric plate were tested by spectrophotometer in black background. The chromatic aberration between the specimens and colorimetric plate were calculated as well as measured the lightness difference, hue angle difference, and saturation difference. Results: the colorimetric data of the dyed specimens are L: 59.81 ~ 78.93; a: 0.36 ~ 9.36; b: 19.62 ~ 26.91. The color space of the specimens and staining solution colorimetric plate was similar and the chromatic aberration was 4.02-6.96 NBS units. The biggest difference between them was the hue angle difference, mean 7.38, followed by the saturation difference, mean 2.31; minimum lightness difference, mean 2.29. Conclusion: staining solution colorimetric plate was suitable to be colorimetric reference for the color-matching of the basic layer of the ceramic. Proper chromatic aberration leaves color revision space for the translucent porcelain veneer.

The influence of mineralogical composition on the colour of clay body

By using methods of Mössbauer spectroscopy, X-ray diffraction and colorimetrics analysis, the dependence of the colour of a ceramic body on its mineralogical composition was determined. In order to achieve this objective, the mineralogical composition and colour parameters of the Girininkai deposit (Lithuania) easily fusible clay and its mixture with the glauconite rock during firing at 600, 800, 1000, and 1025 °C were investigated in detail. By changing firing temperature from 600 to 1025 °C and duration of isothermal exposure from 0.5 to 4 h the amount of iron in hematite increases 5 times, whereas the amount of Fe 3+ incorporated into the crystal lattice of other compounds diminishes 3–4 times if compared with natural clay. For this reason, the value of red colour coordinate increases from 18.44 to 23.65 NBS units and the ceramic body darkens and becomes redish brown. The colour can be intensified even more by adding to the forming mass finely ground glauconite.

The features of the correlation between the pH values and the dissolved oxygen at the Chistaya Balka test area in the Northern Caspian Sea

Abnormally high pH values (up to 9 NBS units and over) were registered by different expeditions at the seaward edge of the Volga River delta. Within the report, the relationship of the pH values, the dissolved oxygen content, and the water temperature are considered using the equations of the thermodynamic theory of carbonate equilibrium. It is shown that the changes of the pH values are nonlinear relative to the content of oxygen. The nonlinearity is most pronounced at high values of the water saturation with oxygen (over 110–120%). A pH value over 9 may be reached in well heated waters at a dissolved oxygen content of 8–9 ml/l. The oxygen content as such is of course high but not excessive and might be caused by the high intensity of the production processes in the waters.

光重合型硬質レジンの厚さが色調変化に及ぼす影響

The purpose of this study was to investigate the influnece of thickness of visible light-cured crown and bridge resins on its color changes.Tristimulus colorimeter was used for color measurement. Disc specimens measuring 5.0mm in diameter, 1.0, 1.5 and 2.0mm in thickness were prepared with enamel, dentin and cervical color paste of each resin. The color changes between before and immediately after irradiation was measured. Color changes were expressed as L*, a* and b* uniform color space (CIE 1976 L*a*b* color difference formula) and total color difference value (ΔEab*, NBS unit) were calculated.ΔEab* value of each resin between before and immediately after irradiation was large and this change was attributable mainly to that of L* and b*.Δ value and ΔEab* value mainly increased according to the increase of speacimen thickness.1.0 vs 1.5 ΔEab* value, except NM, was larger than 1.5 vs 2.0 ΔEab* value.

Resumé of Values of the Faraday.

A resumé is given of the determinations of the value of the Faraday. Values obtained by silver deposition, iodide oxidation, oxalate oxidation, the omegatron, and silver dissolution are reviewed. All values are converted to the unified 12C international scale of atomic weights using the international atomic weights of 1967. Values of the Faraday are given in terms of both the NBS (legal) and absolute units of electrical measure. In the latter the new value for the acceleration due to gravity is used in computing the absolute value of electric current. On this basis and using the atomic weight of silver determined by Shields, Craig, and Dibeler, and converting to the 12C scale, the value of the Faraday is 96,486.9 ± 1.6 absolute coulombs per gram-equivalent which differs by only 1 part per million from the value recommended by the National Academy of Sciences - National Research Council. If the atomic weight of silver recommended in 1967 by the International Atomic Weight Commission is used, the Faraday on the new gravity value is 96,486.5 ± 1.6 absolute coulombs per gram-equivalent which differs by 5 parts per million from that recommended by the National Academy of Sciences - National Research Council. No change in the value of the Faraday adopted by the NAS - NRC Committee is recommended.

織物の色彩設計における色の許容差

By means of Color Difference Meter, I measured the degrees of the color differences, which textile designers tolerate as to the dyed yarns, to be used as shadow fabrics.As a result, it became clear that the color tolerance between color samples and dyed yarns is generally about 1. 0 NBS unit and that the limit of the tolerance is about 4. 0 NBS unit.Whether color matching is good or bad is deter mined regardless of the uses of dyed yarns.It is possible, therefore, to determine with Color Difference Meter instead of with the naked eye of designers.

Colour Differences in Azo Pigments I—The Effect of Precipitation Conditions

The variability in colouring properties, both hue and strength, between batches of the same dye or pigment is a constant source of difficulty to colorant manufacturers, but there is very little published information on the subject. Three azo pigments (Toluidine Red, Hansa Yellow G, and Parachlor Red) were selected for an investigation of the effects of changes in the coupling conditions used in their preparation on the hue of the resulting pigments. The colour differences were measured instrumentally in NBS units. The effect of a given change in conditions differed from pigment to pigment. The differences in colouring properties found between samples of the same pigment made under various conditions are ascribed to physical and not chemical causes.

塗料の色差の肉眼判定とNBS単位値との関係 (第1報)

日常色合わせ作業, または色の検査に従事している者とそうでない者との2群に分けて, 各群10人ずつに淡彩ラッカーエナメル塗板と白ラッカーエナメル塗板との問の色差を肉眼判定させた結果とNBS単位値との関係について調べた。色の取扱いをしている者はそうでない者に比べて色差の肉眼判定の個人差はかなり少ない。赤系統の淡彩色は他の色相の淡彩色に比べて, 肉眼の方がNBS単位値よりも色差を大きく感じる傾向がある。この実験の範囲では肉眼判定による色差はNBS単位値の平方根に比例するという結果を得た。11NBS単位以内の色差では3段階程度に分けて判別すると個人差の少ない判別ができ, その色差段階とNBS単位値の範囲は次のとおりである。1.ほとんど同じ～0.7NBS単位2.わずか違う0.7～4NBS単位3.かなり違う4～11NBS単位

Evaluation of the NBS Unit of Resistance Based on a Computable Capacitor.

An evaluation of the unit of resistance maintained at the National Bureau of Standards, based on the prototype standards of length and time, is described. The evaluation is based on a nominally one-picofarad capacitor whose value may be calculated from its mechanical dimensions to high accuracy. This capacitor is used to calibrate an 0.01-microfarad capacitor. A frequency-dependent bridge involving this capacitor establishes the value of a 104-ohm resistor. Comparison of that resistor with the bank of one-ohm resistors maintaining the NBS unit of resistance establishes that this unit is ΩEU=1.0000023ohms±2.1ppm.The indicated uncertainty is an estimated 50 percent error of the reported value based on the statistical uncertainty of the measurements and allowing for known sources of possible systematic errors other than in the speed of light, assuming that the speed of light c=2.997925×1010cm/sec.

Use of a Digital Readout Unit in Converting Spectrophotometric Data to Color Coordinates

Spectrophotometric data are automatically entered on IBM punched cards by means of a Librascope Digital Readout Unit for the General Electric Recording Spectrophotometer. Conversion to color coordinates is subsequently carried out on an IBM 650 computer. The over-all precision of the spectrophotometer-digitizer-computer system corresponds to 95% confidence limits of about 0.001 in trichromatic coefficients x and y or about 0.7 NBS units of color difference (Adams chromatic value formula, normalized as in ASTM Method D1482-57T). Taking results of the National Bureau of Standards as correct, the accuracy of the average of several measurements is within 0.0005 in trichromatic coefficients or 0.4 NBS units of color difference. The error frequency of the digitizer is currently below 1 in 7000 readouts, and can be reduced to less than 1 in 200 000 readouts.