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Objectives Materials and Methods Results Conclusions Clinical Significance To evaluate the influence of preheating and water storage on color, whiteness, and translucency of one‐shaded, group‐shaded, and multi‐shaded resin‐based composites.A total of 270 samples were fabricated from one‐shaded (Omnichroma), group‐shaded (Optishade MD), and multi‐shaded (Enamel Plus HRI) resin‐based composites and divided into six groups: no heating (control) and 1–5 heatings (test) (n = 15). The CIE L*, a*, b*, C*, and h° color coordinates were registered over white, black, and gray backgrounds with a spectrophotometer before and after 24, 72, 144 h water storage. Kruskal–Wallis test was used to evaluate differences in the color coordinates, whiteness index, and translucency parameter (α = 0.05). The Mann–Whitney U test was performed with a Bonferroni correction (p < 0.001) for pairwise comparisons. CIEDE2000 color, whiteness, and translucency differences between groups and subgroups were evaluated using their respective 50%:50% perceptibility and acceptability thresholds.Preheating influenced color coordinates, whiteness index, and relative translucency parameters (p < 0.001). Although color differences were below the acceptability threshold for all materials, translucency differences were above the acceptability threshold for Omnichroma. Water storage significantly influenced the whiteness index of Optishade MD (p < 0.001).Preheating had a more considerable effect on the color, whiteness, and translucency of one‐shaded resin‐based composite, while water storage influenced group‐shaded resin‐based composite more importantly.Preheating influences the color, whiteness level, and translucency of the resin‐based composites, but the variations remain generally clinically acceptable; however, practitioners should be aware that the modifications in translucency for one‐shaded resin‐based composites could be more important than for group‐shaded and multi‐shaded resin‐based composites. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the influence of air‐abrasion of enamel with three different desensitizing powders on the whitening effect of a bleaching gel containing 40% H2O2, which was used for in‐office tooth bleaching. Materials and Methods: Forty human incisors, extracted and prepared, were acquired for this study and subsequently randomized into four groups (n = 10). The control group specimens underwent no pretreatment prior to the bleaching procedure, whereas the remaining three groups underwent air abrasion using distinct desensitizing powders; (a) Sylc, which contains bioglass 45S5; (b) BioMinF, which contains calcium phospho‐fluoro‐silicate glass; and (c) MI Pearls, which contains nano‐hydroxyapatite, 1 h preceding the Opalescence Boost PF 40% bleaching procedure. Color measurements were conducted using a double‐beam UV–Vis spectrophotometer at four distinct time points (prior to bleaching, 24 h, 15 days, and 30 days post‐bleaching). Results: Tooth color change outcomes revealed that there were no statistically significant results with respect to the interaction of the two criteria (treatments and time) (p = 0.990). Additionally, there were no statistically significant results with respect to the main effects of treatments (p = 0.385), while there were statistically significant effects with respect to the time criterion (p = 0.013). Conclusions: The use of the tested desensitizing powders prior the bleaching procedure did not affect the tooth color change induced by the tested bleaching agent. Clinical Significance: Tooth color change and whiteness are not affected by air‐abrasion desensitizing treatments when applied prior to in‐office bleaching procedures. [ABSTRACT FROM AUTHOR]

ABSTRACT Objective Materials and Methods Results Conclusion Clinical Significance This systematic review and meta‐analysis compared the accuracy of intraoral scanners and spectrophotometers in determining tooth shade.An electronic search of five databases (PubMed, Scopus, Embase, Web of Science, CENTRAL) was conducted on October 19, 2023. A total of 163 studies were identified from the databases, of which 23 articles were eligible for inclusion. In vivo and in vitro quasi‐experimental studies were included. After data extraction, a quantitative analysis was performed to determine the accuracy of the intraoral scanner in subgroups using four outcomes: trueness and precision with different measurement locations. A random‐effects model was used to pool effect sizes. The pooled proportion with a 95% confidence interval (CI) was used for the effect size measure.Eleven articles were included in the meta‐analysis. Trueness with the intraoral scanner was between 0.28 (CI: 0.09–0.60) and 0.38 (CI: 0.24–0.53). Repeatability was between 0.81 (CI: 0.64–0.91) and 0.85 (CI: 0.74–0.92). Trueness showed low, and precision had moderate certainty of evidence.The trueness of shade matching with intraoral scanners is low compared to spectrophotometers, although the precision is considered high and is similar to spectrophotometers.Shade determination with intraoral scanners is not recommended. [ABSTRACT FROM AUTHOR]

Objective: To compare the color change, the risk and intensity of tooth sensitivity (TS), and gingival irritation (GI) of at‐home bleaching applied on the buccal surface only or the buccal and lingual surfaces. Materials and Methods: Sixty patients with canines A2 or darker were selected and their superior arches were randomized in two groups: at‐home bleaching on the buccal‐only or on the buccal and lingual surfaces, with 7.5% hydrogen peroxide, for 1 h daily/2 weeks. The color change was evaluated at baseline, 7, 14 days, and 1 month after bleaching using shade guides scales (ΔSGU) and a spectrophotometer (ΔEAB, ΔE00, and ΔWID). Risk and intensity of TS and GI were recorded daily using visual analogic scale (0–10). Patient satisfaction was evaluated with the orofacial esthetics. Paired t‐test, McNemar's, and Wilcoxon signed‐rank test were used for data analysis (α = 5%). Results: Neither the color change nor the risk/intensity of TS was statistically different between groups (p > 0.05). Patient satisfaction increased after bleaching for both groups (p < 0.05). Conclusion: The addition of one contact surface does not result in an increased whitening degree compared to bleaching applied solely on the buccal surface. Clinical Significance: Understanding the influence of surfaces interacting with the bleaching agent is crucial for comprehending the bleaching mechanism and avoiding unnecessary material expenses. Notably, employing the buccal‐only technique is sufficient to achieve the desired efficacy. [ABSTRACT FROM AUTHOR]

ABSTRACT Objective Material and Methods Result Conclusion Clinical Implication New shade‐matching devices are available for clinical use, but their accuracy and reliability have not been investigated. This in vitro study compared the accuracy and reliability of a shade‐matching colorimeter (Optishade), a spectrophotometer (VITA Easyshade V), and visual shade matching in simulated clinical conditions.Shade matching was conducted with two digital devices; (Optishade and Vita Easyshade) and the visual shade selection method, with a new 16‐tab Vita Classical shade guide. Shade tabs were placed within a gingival matrix and measurements were taken from the central area of each shade tab enclosed in a black box to simulate the oral cavity. Visual assessments were conducted independently by two examiners. For the reliability assessment, each shade tab was measured 20 times by each examiner. Accuracy was calculated as a percentage of the matching readings with the actual shade per each tab. Data were analyzed with the one‐way ANOVA test (α = 0.05) and Pairwise Comparison (Bonferroni Post hoc Test) to assess accuracy. The reliability evaluation was conducted by comparison between both examiners using mean and standard deviation; by a two‐tailed t‐test for the independent samples for all the three groups included in the study.The shade matching accuracy of Optishade was 97.50%, Vita Easyshade 89.38%, and visual method 62.19%. Statistically, high significant difference in accuracy (p < 0.001) was found when comparing both Optishade and VITA Easyshade with the visual method. Additionally, there was statistically significant difference in accuracy (p < 0.05) when Optishade was compared to Vita Easyshade. The reliability of the Optishade was 99.6% and Vita Easy shade was 99.38%. Statistically, showed no statistically significant difference in the reliability of shade match obtained within the same group when comparing the readings of Examiner 1 and Examiner 2 (p > 0.05).The colorimeter demonstrated the highest accuracy, followed by the spectrophotometer, and the visual shade selection method. Both digital methods investigated in this study showed comparable reliability.The results of this study emphasize the clinical advantage of digital shade‐matching devices over visual shade‐matching. The colorimeter offers high accuracy for shade matching and should be considered to use for shade matching especially with restorations in the esthetic zone. [ABSTRACT FROM AUTHOR]

Background: Gestational Diabetes Mellitus (GDM) poses significant risks to maternal and fetal health. Current diagnostic methods based on glucose tolerance tests have limitations for early detection. tRNA‐derived small RNAs (tsRNAs) have emerged as potential molecular regulators in various diseases, including metabolic disorders. However, the diagnostic value of tsRNAs in plasma for early GDM or postpartum remains unclear. Methods: This longitudinal study profiled the expression of tsRNAs across different gestational stages and postpartum in women with GDM (n = 40) and healthy control gestational women (HCs, n = 40). High‐throughput small RNA sequencing identified candidate tsRNAs, which were then validated and correlated with clinical biochemical markers such as fasting blood glucose (FBG), HOMA‐IR, and GHbA1c. Results: tRF‐1:32‐Val‐AAC‐1‐M6, tRF‐1:31‐Glu‐CTC‐1‐M2, and tRF‐1:30‐Gly‐CCC‐1‐M4 were consistently upregulated in the GDM group compared to HCs during the second trimester (p < 0.05). Only tRF‐1:31‐Glu‐CTC‐1‐M2 was highly expressed during the first trimester, and tRF‐1:30‐Gly‐CCC‐1‐M4 increased during postpartum. tRF‐1:31‐Glu‐CTC‐1‐M2 showed a significant correlation with FBG levels in the first trimester (R = 0.317, p = 0.047). The expression of tRF‐1:30‐Gly‐CCC‐1‐M4 was significantly correlated with HOMA‐IR (r = 0.65, p < 0.001) and GHBA1c (r = 0.33, p = 0.037) during postpartum. A joint diagnostic model incorporating tsRNAs expression and clinical markers demonstrated enhanced predictive power for GDM (ROC AUC = 0.768). Conclusion: Our results revealed distinct expression patterns of specific tsRNAs in GDM, showcasing their correlation with key metabolic parameters. This underscores their promising role as biomarkers for early prediction and diagnosis of GDM. The integration of tRFs into a composite biomarker panel holds the potential to improve clinical outcomes by enabling personalized risk assessment and targeted interventions. [ABSTRACT FROM AUTHOR]

Objectives: Chlorhexidine (CHX)‐based products are the most effective chemical agents used in plaque control and oral disinfection. One of their side effects is tooth and restoration staining. For this reason, CHX products with anti‐discolouration systems (ADS) have been developed. The aim of this in vitro study was to compare different CHX‐based products (gel and mouthwash) with or without ADS in composite colour modification. Methods: Two hundred specimens were created, 100 of which were made of packable composite and 100 of flowable composite. After 24 h, colour coordinates (L*, a*, b*, C*, h°) were recorded using a spectrophotometer (T0). Then, all samples were subjected to a CHX/tea staining model and immersed in human saliva for 2 min. Composite specimens were divided in 10 groups (N = 20). Control groups (PC, FC) were soaked in distilled water and test groups (PG, PGads, FG, FGads, PM, PMads, FM and FMads) were immersed in CHX‐based solutions or brushed with CHX gel. Then the cycle was repeated 6 times, and colour differences (ΔEab and ΔE00) were finally calculated. Results: Through flowable composites, FC and FG showed the highest colour differences, respectively ΔEab = 3.48 ± 1.0, ΔE00 = 2.24 ± 0.6 and ΔEab = 2.95 ± 1.3, ΔE00 = 1.53 ± 0.6. In the composite groups instead, PM and PMads showed the highest colour differences, respectively ΔEab = 2.78 ± 1.3, ΔE00 = 1.94 ± 0.8 and ΔEab = 2.71 ± 1.4, ΔE00 = 1.84 ± 0.9. Conclusions: CHX‐containing products are able to cause stains on restorative composite materials. Discolouration is more likely to occur in flowable composites than packable composites, and ADS‐containing products cause fewer pigmentations than CHX products without ADS. Packable composites showed more staining after mouthwash treatment, whereas flowable composites underwent higher discolouration after treatment with gels. [ABSTRACT FROM AUTHOR]

Recognising the need for objective imaging‐based technologies to assess wound healing in clinical studies, the suction blister wound model offers an easily accessible wound model that creates reproducible epidermal wounds that heal without scarring. This study provides a comprehensive methodology for implementing and evaluating photography‐based imaging techniques utilising the suction blister wound model. Our method encompasses a protocol for capturing consistent, high‐quality photographs and procedures for quantifying these images via a visual wound healing score and a computer‐assisted colour analysis of wound exudation and wound redness. We employed this methodology on 16 suction blister wounds used as controls in a clinical phase‐1 trial. Our method enabled us to discern and quantify subtle differences between individual wounds concerning healing progress, erythema and wound exudation. The wound healing score exhibited a high inter‐rater agreement. There was a robust correlation between the spectrophotometer‐measured erythema index and photography‐based wound redness, as well as between dressing protein content and photography‐based dressing yellowness. In conclusion, this study equips researchers conducting clinical wound studies with reproducible methods that may support future wound research and aid in the development of new treatments. [ABSTRACT FROM AUTHOR]

Objectives: Evaluate the bleaching efficacy (BE) and tooth sensitivity (TS) of in‐office bleaching using different application tips. Methods: Forty‐eight participants were selected (split‐mouth), one to receive bleaching with an attached brush tip and one with a conventional tip. The procedure was performed with Whiteness Automixx Plus 35%. The BE was evaluated at the beginning, weekly, one and 12 months post‐bleaching with a Vita Easyshade spectrophotometer (ΔE*ab, ΔE00, and WID) and with Vita classical A1‐D4 and Vita Bleachedguide shade guides units (ΔSGU). Absolute risk and intensity of TS were recorded using the Visual Analogue Scale. The equivalence of BE was analyzed using the two one‐sided t‐tests for paired samples. The absolute risk of TS was evaluated using the McNemar test, and the TS intensity was measured with the paired t test (α = 0.05). Results: The equivalence of BE was observed for both groups in all color evaluations (p > 0.05). A lower absolute risk and intensity of TS were observed for the attached brush tip when compared with the conventional tip (p < 0.003 and p < 0.0001). Conclusion: Using an attached brush tip showed the same BE as a conventional tip. However, for the attached brush tip, there was a reduction in TS. Clinical Significance: The applicator‐attached brush tip is recommended for in‐office dental bleaching, because of the possible reduction in risk and intensity of TS. [ABSTRACT FROM AUTHOR]

Infrared (IR) filters and screens find application in energy‐efficient buildings, windows, and solar panels. Such filters benefit solar cells by preventing efficiency losses caused by heating. Polymer‐nanocomposite films are good candidates for developing IR screens. Compared to prior research on IR filters, we show how the addition of silver nanoparticles (AgNPs) can improve the material's IR reflective nature while retaining high transmittance in the visible region. Polydimethylsiloxane (PDMS) film with AgNPs (~100 μm thick) is made using the doctor blade technique. We observe no transparency loss over the 0.005–0.02 vol% loading of AgNPs in PDMS, indicating the promising application of this transparent film. Furthermore, the distribution of AgNPs is found to be uniform, ensuring consistency, and preventing agglomeration. A contact angle of ~1120 is observed for these films, which is comparable to pristine PDMS film. Using a UV–Vis–NIR spectrophotometer, greater than 7.66% weighted average reflectance is observed in the near‐infrared (NIR) region and above 91.5% transmittance in the visible region. The precise role and influence of the functional group's presence were revealed by Fourier transform infrared (FTIR) spectroscopy. The thermal analysis (TGA) of the films revealed thermal stability of up to 400°C, which is comparable to pristine PDMS. Overall, the synergistic combination of AgNPs and PDMS produces a hydrophobic IR filter with enhanced optical characteristics and thermal stability. [ABSTRACT FROM AUTHOR]

The current research article has investigated the synthesis and characterization of novel iron nanoparticles (INPs) from neem and betel leaves extract combination using response surface methodology–central composite design and coated with chitosan–curcumin (CCINPs) as a biocompatible and contrast agent for magnetic resonance imaging (MRI). The coating of INPs with chitosan and curcumin (CCINPs) was carried out using a simple, easy, chemical‐free ultrasonication method and characteristics were confirmed by UV–visible (Vis) spectrophotometer (UV–Vis), Fourier‐transform infrared spectroscopy, X‐ray diffraction, scanning electron microscope, atomic force microscopy, and vibrating sample magnetometer. The biocompatibility of the particles was ensured by conducting hemolytic and cell viability assays. The nanoparticle was found to be nonhemolytic (<5%) up to 150 μg/mL for both INPs and CCINPs. The cell viability was stable (peripheral blood mononuclear cells‐PBMCs) till 48 h at 150 μg/mL of INPs and CCINPs. Both the test results produced were found to be biocompatible and additionally, an in vitro MRI study of INPs and CCINPs demonstrated the efficiency of the nanoparticle as a negative contrast agent with enhanced contrast nature in CCINPs. Thus, overall results indicate that the green synthesized chemical‐free novel CCINPs could be a potential candidate for a wide range of applications such as MRI, drug delivery, and in magnetic fluid hyperthermia. [ABSTRACT FROM AUTHOR]

BODIPY based molecules functionalized with water soluble moieties have been developed and recognized as liable triplet photosensitizers for phototherapeutic applications. In this work, we have prepared BODIPY analogues with dicarboxylic acid groups and bearing iodine or fullerene moieties for efficient intersystem crossing which display far‐red absorption band and high singlet oxygen production both in organic and aqueous media. In this perspective by using similar design the effect of the halogenation of the dyes versus spin converter on the skeleton were compared. The structures of the synthesized BODIPYs and BODIPY‐C60 (6–10) were elucidated by mass, 1H and 13C NMR spectroscopic techniques. Photophysical and photochemical properties of the compounds were examined using UV‐Vis. absorption and fluorescence emission spectrophotometers. The absorption intensities of the trap molecules (DPBF and ADBA) reduced because of singlet oxygen generation in the media. This study may provide useful infrastructure to elucidate the relationship between the use of fullerene (9) or iodine (10) where singlet oxygen quantum yield of 9 and 10 are determined as 0.87 and 0.97 respectively. [ABSTRACT FROM AUTHOR]

This study illustrates at‐line application of hyperspectral imaging in the visible range for quality control of large‐scale offset printing. In particular, the measurement stability of a competitive device is assessed and compared to traditional handheld and desktop spectrophotometers. The performance of the commercially available instruments was assessed based on collected spectra and their corresponding L*, a*, and b* values. The printing process was described by hyperspectral images (in visible range) of selected regions from template color fields acquired at 17 sampling occasions. Spectra constituting hyperspectral images were visualized and evaluated in the space of significant principal components obtained from the principal component analysis. Furthermore, confidence ellipses were constructed for each set of spectra characterizing a specific moment of the printing process. Comparing their mutual locations, shapes, orientations, and sizes enabled effective visualization of process variability and was more comprehensive regarding the classic approach based on information provided by desktop and handheld spectrometers. This study demonstrates the effectiveness of hyperspectral imaging for real‐time quality control in large‐scale offset printing, in particular by studying sampling distributions. By assessing measurement stability and comparing competitive devices with traditional spectrophotometers, it reveals the advantages of hyperspectral imaging in measurement speed, spatial dimension inclusion, and process variability visualization. Chemometric analysis aids in effective color assessment, while local segmentation can offer insights into color perception, crucial for process monitoring and detection of various sources of variation. [ABSTRACT FROM AUTHOR]

Summary Colorimetric determination of nitrate with a detection method adapted to field conditions and portable, digital measuring devices. A highly sensitive method for the determination of nitrate in lentic waters in the field has been established. The nitrate detection works analogous to the color reaction known from the Grieß reagent. The procedure has been modified in a way that it can be carried out on site on the water body under field conditions. For this purpose, a measuring device has also been developed that allows simple colorimetric evaluation. This so‐called "boxometer" consists of two mobile phones and a few everyday items and can be easily rebuilt by everyone. The colorimetric analysis is carried out using the RGB system of digital devices in an epi‐illumination setting, which allows a sensitive investigation of the absorption of the samples within narrow limits. This method can also be used in many ways in teaching or where colorimetric measurements should be carried out but no spectrophotometer is available. [ABSTRACT FROM AUTHOR]

Objective: The objective was to assess the repeatability of three spectrophotometers, based on the CIELCh factors and shadeguide reference measurements. Materials and Methods: Color analysis was performed using three devices: Rayplicker, Easyshade 4, and Easyshade V. Five repeated measures were performed by the same operator, on the right central maxillary incisor of 30 patients. The CIELCh factors were retrieved and the intra‐class correlation was calculated. The Vita Classical and Vita 3D Master shadeguides were used to evaluate the respective Fleiss' Kappa factors. Results: Rayplicker and Easyshade V demonstrated strong intra‐class correlation based on the CIELCh factors: 0.98, 0.99, and 0.91 for Rayplicker, and 0.95, 0.99, and 0.93 for Easyshade V, for the L*, C*, and h* parameters, respectively. Regarding the repeatability of the shadeguide data, while Easyshade 4 had the best repeatability when using the Vita Classical as a reference, Rayplicker and Easyshade V showed better repeatability when using the Vita 3D Master. Conclusion: These findings suggest that both Rayplicker and Easyshade V are reliable devices for measuring CIELCh parameters. In terms of shadeguide references, the reliability of spectrophotometers is generally lower compared to the CIELCh measurements. Clinical Significance: Given their good repeatability, both the Rayplicker and the Easyshade V spectrophotometers are reliable tools for prosthetic dental practices. [ABSTRACT FROM AUTHOR]

Objective: Measure and compare the mechanical properties, translucency, and fluoride‐releasing capabilities of EQUIA Forte HT against Fuji IX GP and ChemFil Rock. Materials and Methods: Ten specimens of each material were fabricated for compressive strength (CS), flexural strength (FS), and surface hardness analysis at 24 h and 7 days. The L*a*b* values were measured against a black‐and‐white background using a spectrophotometer to analyze the translucency parameter (TP). Fluoride release was recorded after 2 months of immersion in distilled water. The mean data was analyzed by 1‐ and 2‐way ANOVA (α = 0.5). Results: EQUIA Forte HT showed higher CS, surface hardness, and FS values (p < 0.05) compared with Fuji IX GIC, while no significant difference was found in FS values between EQUIA Forte HT and Chemfil Rock (p > 0.05). The EQUIA Forte HT exhibited significantly higher translucency in comparison to both ChemFil Rock (p < 0.001) and Fuji IX GICs (p < 0.05). An increase (p > 0.05) of fluoride release was observed for EQUIA Forte HT. Conclusion: The EQUIA Forte HT Glass‐ionomer cements (GIC) offers enhanced translucency, improved strength, and enhanced fluoride‐releasing properties compared to the traditionally used Fuji IX GIC and ChemFil Rock GICs. This material might have a wide range of clinical applications due to its improved strength and optical properties. Clinical Significance: Glass‐ionomer dental restorative materials possess unique advantageous characteristics. However, its poor mechanical and optical properties have typically limited its clinical applications. Efforts to improve these properties have resulted in enhanced GICs. EQUIA Forte HT GIC offers enhanced mechanical and optical properties with potential applications in posterior and anterior restorative procedures. [ABSTRACT FROM AUTHOR]

Background: The discoloration potential of dental materials and applications such as vital pulp therapy also cause discoloration due to the presence of blood. Dentin tubule sealing methods could be used for the prevention of discoloration. Aim: The purpose of this study was to evaluate the effect of sealing pulp chamber walls with Nd:YAG laser against discoloration caused by tricalcium silicate‐based materials in the presence and absence of blood contamination. Design: Eighty‐one extracted human maxillary incisors were prepared and randomly divided into nine groups according to the Nd:YAG laser application, the cement to be used (NeoMTA Plus/Biodentine), and the presence or absence of blood. The color measurements were obtained with a spectrophotometer at baseline and then at the sixth (T1) and 12th (T2) months thereafter. Results: Sealing with Nd:YAG laser and placing NeoMTA Plus or Biodentine on human blood significantly increased discoloration at T1 and T2 (p <.05). Similarly, without sealing the cavity and placing NeoMTA Plus or Biodentine on human blood significantly increased discoloration at T1 and T2 (p <.05). Conclusion: Regardless of sealing the dentin tubules with Nd:YAG laser, NeoMTA Plus and Biodentine caused more discoloration in the presence of blood contamination. [ABSTRACT FROM AUTHOR]

Motivated from the extraordinary properties of CeO2 nanomaterial, this article is directed toward the synthesis of recyclable polyvinyl alcohol–CeO2 polymer nanocomposite with variable wt% of CeO2 and investigating their improvements in structural, electrical, optical, and surface properties. The crystalline size and micro‐strain are measured using X‐ray diffraction (XRD) data. Ultraviolet–visible–near‐infrared spectrophotometer is used to study the optical characteristics. Absorbance with redshift is found to enhance; while optical bandgap is reduced from 2.51 to 2.36 eV on increasing wt% of CeO2 nanofiller. The mechanism of reduction in bandgap is supported by the XRD analysis. Refractive index is found to vary from 2.54 to 2.59 and the range of Urbach energy varies from 1.19 to 0.42 eV on increasing the amount of nanofillers. Surface morphology, dielectric constant, and electrical conductivity are also found to improve with increasing wt% of nanofiller. The dielectric constant is improved from 60 to 120 at 1.5 Hz. The rise in conductivity with increasing wt% of CeO2 and rising frequency is due to the enhancement of mobility of the charge carriers and ionic hopping mechanism in conduction process. Characterization outcomes suggest that the prepared composites can be claimed as useful in fabricating the flexible optoelectronic devices. [ABSTRACT FROM AUTHOR]

This clinical trial investigated the effects of pre‐application enamel moistening on the impact of a 37% carbamide peroxide whitener on tooth color changes and the influence of repositioning guide colors. Forty participants were randomly assigned to in‐office tooth bleaching with either moistened enamel (experimental) or dry enamel (control). The whitener was applied for 45 min over two sessions. Tooth color was visually measured or assessed using a spectrophotometer with purple or green silicone guides. Tooth bleaching was assessed using CIE76 (ΔEab) and CIEDE2000 (ΔE00) formulas and by whitening and bleaching index score changes. Moistening the enamel did not significantly affect tooth color. However, the guide color choice only impacted tooth color when measured instrumentally. At baseline, the green guide resulted in statistically significantly whiter teeth than the purple guide. Less pronounced differences in the b* coordinate between baseline and final measurements were found using the green guide. The green guide also produced lower ΔEab values and less change in indexes. In conclusion, moistening the enamel did not significantly impact tooth color changes. However, the repositioning guide color influenced the tooth bleaching measured instrumentally, except for ΔE00. [ABSTRACT FROM AUTHOR]

Plant‐based nanoparticles (NPs) have found great interest among various scientist in the present era and used in various sector including medicine, agriculture, and food industry. The various chemical constituents of plants aid in the bioreduction of metal ions to a nanoscale. Among the various NPs synthesized, zinc oxide (ZnO) NPs hold a premier position. ZnO NPs have use in textile, cosmetic, diagnostics, optoelectronics, photocatalysis, diodes, and many other areas. NPs synthesized through green synthesis have a potentially greater role in treating clinical pathogens. Present investigations show a simple eco‐friendly method for the synthesis of ZnO NPs from the husk of sunflower seeds. Sunflower is an economically important crop, for the formation of edible oil. The husk is considered to be a waste, product in oil industry, however, the biomolecules present in sunflower husk can be used to produce ZnO NPs. Present investigations reveal formation of ZnO NPs and investigations of their structure through scanning electron microscope (SEM), X‐ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. Their optical properties have been studied by ultraviolet–visible spectrophotometer (UV–Vis) and fluorophotometer. ZnO NPs have also been investigated for their potential phytoremedial properties. [ABSTRACT FROM AUTHOR]

Aim: The use of cannabis, which contains multiple antimicrobials, may be a risk factor for periodontitis. We hypothesized that multiple oral spirochetes would be phytocannabinoid‐resistant and that cannabidiol (CBD) would act as an environmental stressor to which Treponema denticola would respond transcriptionally, thereby providing first insights into spirochetal survival strategies. Materials and Methods: Oral spirochete growth was monitored spectrophotometrically in the presence and absence of physiologically relevant phytocannabinoid doses, the transcriptional response to phytocannabinoid exposure determined by RNAseq, specific gene activity fluxes verified using qRT‐PCR and orthologues among fully sequenced oral spirochetes identified. Results: Multiple strains of oral treponemes were resistant to CBD (0.1–10 μg/mL), while T. denticola ATCC 35405 was resistant to all phytocannabinoids tested (CBD, cannabinol [CBN], tetrahydrocannabinol [THC]). A total of 392 T. denticola ATCC 35405 genes were found to be CBD‐responsive by RNAseq. A selected subset of these genes was independently verified by qRT‐PCR. Genes found to be differentially activated by both methods included several involved in transcriptional regulation and toxin control. Suppressed genes included several involved in chemotaxis and proteolysis. Conclusions: Oral spirochetes, unlike some other periodontal bacteria, are resistant to physiological doses of phytocannabinoids. Investigation of CBD‐induced transcriptomic changes provided insight into the resistance mechanisms of this important periodontal pathogen. These findings should be considered in the context of the reported enhanced susceptibility to periodontitis in cannabis users. [ABSTRACT FROM AUTHOR]

A novel chiroptical spectrophotometer, Multichannel (MC)‐circular dichroism (CD), which does not require a wavelength scan and provides artifact‐free CD spectra in seconds, was developed by solving the incompatibility problem between data acquisition and modulation timescales. The design and instrumentation are compared with the Universal Chiroptical Spectrophotometer (UCS)‐1, which can measure artifact‐free CD spectra in the solid state. Enantiomeric single crystals composed of achiral components, α‐Ni(H2O)6・SO4, and achiral films with substantial macroscopic anisotropies were measured on both MC‐CD and UCS‐1 and compared. [ABSTRACT FROM AUTHOR]

Precise spectral ultraviolet (UV) measurements are needed to ensure human protection as well as to support scientific research. Quantifying the uncertainty of the UV spectra recorded is crucial to evaluate the quality of the measurements which is needed, in turn, for the assessment of their reliability. However, for double‐monochromator spectroradiometers, the analytical derivation of this uncertainty is a challenging task due to the difficulties involved in propagating individual uncertainties. Under these circumstances, a Monte Carlo simulation is a reliable alternative as it does not require the calculation of partial derivatives and considers both nonlinear effects and correlations in the data. In the present study, the uncertainty of the spectral UV irradiance measured by a Brewer MKIII spectrophotometer is evaluated using a Monte Carlo approach. This instrument belongs to the National Institute of Aerospace Technology and has successfully participated in several international campaigns, which ensures its precise calibration. The average expanded uncertainty (k = 2) of the global UV irradiance measured by this instrument varies between 10% at 300 nm and 7% at 363 nm. At shorter wavelengths, it increases sharply due to thermal and electronic noise as well as wavelength misalignment. The results indicate that a Brewer spectrophotometer is suitable for climatological studies and model validation. Nevertheless, a substantial reduction of these uncertainties might be required for accurately detecting long‐term UV trends. Although the study focused on a Brewer spectrometer, the methodology used for the uncertainty analysis is general and can be adapted to most UV spectroradiometers. Plain Language Summary: The solar ultraviolet (UV) spectrum covers the wavelength range from 100 to 400 nm. Although it represents less than 10% of the total radiation reaching the earth's surface, it is of great importance as it can be harmful to humans, aquatic, and terrestrial ecosystems. To study its effects, high‐quality measurements are needed. To determine the quality of the irradiance recorded its uncertainty must be first evaluated. Most techniques used for uncertainty estimation rely on the calculation of partial derivatives, which are difficult to obtain for most instruments measuring UV irradiance. The reason for this is that the mathematical expression relating some uncertainty sources and the measured irradiance is complex, with unknown correlations between the different uncertainty sources. To solve this problem, the Monte Carlo technique was used instead of the analytical one. The Monte Carlo approach is easier to implement and needs no calculation of partial derivatives. The method was implemented for a Brewer spectrometer, one of the preferred devices to measure UV irradiance. The results indicate that the Brewer is suitable for model validation, but a substantial reduction of its uncertainty might be needed to accurately detect spectral UV trends. Key Points: A Monte Carlo technique has been implemented to obtain the uncertainty of the spectral ultraviolet recorded by a Brewer MKIII spectrometerThe methodology used for the uncertainty propagation is general and can be adapted to most spectroradiometers used in ultraviolet (UV) researchBrewer spectrometers are suitable for model and satellite validation but might be limited in the determination of spectral UV trends [ABSTRACT FROM AUTHOR]

Objective: This study assessed how the distance from the composite interface and the underlying chromatic substrate affect the color adjustment potential (CAP) of two single‐shade composites. Materials and Methods: Cylinder‐shaped specimens were created using Vittra APS Unique (VU), Charisma Diamond One (DO), and a shaded (A3) composite. Some single‐shade specimens were surrounded by the A3 composite, forming dual specimens. Color measurements of simple specimens were taken against a gray background using a spectrophotometer. All specimens were positioned at a 45° angle in a viewing booth under illuminant D65, and images were captured with a DSLR camera against gray or A3 backgrounds. Image colors were measured using image processing software and converted to CIELAB coordinates. Color differences (ΔE00) between the single‐shade composites and the A3 composite were calculated. CAP was determined by comparing data from simple and dual specimens. Results: No clinically significant differences were observed between color measurements obtained from images and the spectrophotometer. CAP was higher for DO compared to VU and increased as the distance from the composite interface decreased and when specimens were positioned against an A3 background. Conclusion: The color adjustment potential increased with decreased distance from the composite interface and against a chromatic background. Clinical Significance: Achieving satisfactory color match in restorations using single‐shade composites is crucial, and selecting an appropriate underlying substrate is essential. The color adjustment gradually decreases from the restoration margins towards its center. [ABSTRACT FROM AUTHOR]

Assessment of milk fatty acids has been proposed to support farm management practices including adjustment of feeding regimes and monitoring animal status. This study assessed the performance of a miniaturised near infrared (NIR) sensor for assessment of fatty acids in milk. Samples (n = 483) were from 114 farms, varying in lactation stages within two production seasons and included different dairy breeds. The fatty acids (C4:0, C6:0, C14:0, C16:0, C18:1 c9, SFA, MUFA, SCFA, BCFA) showed Ratio of performance to deviation values higher than two. The performance was equivalent to other independent studies utilising NIR. However, in this study, we used a low‐cost NIR spectrophotometer suitable for on‐the‐farm use. [ABSTRACT FROM AUTHOR]

A method is described for determining and calibrating the CIE Whiteness Index (WI) of an OBA‐treated specimen without incorporating into the measurement system a mechanically adjustable UV filter. The method requires spectrophotometric measurement of the specimen under two lights: UV‐excluded to infer the reflectance r(λ) and UV to infer the fluorescence profile f(λ). Also required is a stored illuminant spectrum Iin(λ) that covers at least the whole visible wavelengths. Only one scalar value k is then needed to mathematically characterize the total spectral radiance factor (TSRF) of the same specimen under Iin(λ). Calibration uses a reference specimen with known WI, and adjusts k until the computed WI matches the reference WI value. If Iin(λ) is the illuminant chosen from ASTM E313 to define the WI, the k adjustment reduces to solving a single quadratic equation for k that involves the reference WI. In general, relative to directly measuring a specimen's TSRF, it is more instrument‐independent to use the current method to characterize TSRF. Therefore, if a fluorescent specimen is measured using UV and UV‐excluded illuminants, a complete, instrument‐stable characterization of the specimen's TSRF can be derived by adjusting k, which can be done through a closed‐form relation of k to the WI. [ABSTRACT FROM AUTHOR]

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has greatly affected all aspect of life. Although several vaccines and pharmaceuticals have been developed against SARS-CoV-2, the emergence of mutated variants has raised several concerns. The angiotensin-converting enzyme (ACE2) receptor cell entry mechanism of this virus has not changed despite the vast mutation in emerging variants. Inhibiting the spike protein by which the virus identifies the host ACE2 receptor is a promising therapeutic countermeasure to keep pace with rapidly emerging variants. Here, we synthesized two ACE2-derived peptides, P1 and P25, to target and potentially inhibit SARS-CoV-2 cell entry. These peptides were evaluated in vitro using pseudoviruses that contained the SARS-CoV-2 original spike protein, the Delta-mutated spike protein, or the Omicron spike protein. An in silico investigation was also done for these peptides to evaluate the interaction of the synthesized peptides and the SARS-CoV-2 variants. The P25 peptide showed a promising inhibition potency against the tested pseudoviruses and an even higher inhibition against the Omicron variant. The IC50 of the Omicron variant was 60.8 μM, while the IC50s of the SARS-CoV-2 original strain and the Delta variant were 455.2 μM and 546.4 μM, respectively. The in silico experiments also showed that the amino acid composition design and structure of P25 boosted the interaction with the spike protein. These findings suggest that ACE2-derived peptides, such as P25, have the potential to inhibit SARS-CoV-2 cell entry in vitro. However, further in vivo studies are needed to confirm their therapeutic efficacy against emerging variants. [ABSTRACT FROM AUTHOR]

Sensors that use ultraviolet (UV) light absorption to measure nitrate in seawater at in situ temperatures require a correction to the calibration coefficients if the calibration and sample temperatures are not identical. This is mostly due to the bromide molecule, which absorbs more UV light as temperature increases. The current correction applied to in situ ultraviolet spectrophotometer (ISUS) and submersible ultraviolet nitrate analyzer (SUNA) nitrate sensors generally follows Sakamoto et al. (2009, Limnol. Oceanogr. Methods 7, 132–143). For waters warmer than the calibration temperature, this correction model can lead to a 1–2 μmol kg−1 positive bias in nitrate concentration. Here we present an updated correction model, which reduces this small but noticeable bias by at least 50%. This improved model is based on additional laboratory data and describes the temperature correction as an exponential function of wavelength and temperature difference from the calibration temperature. It is a better fit to the experimental data than the current model and the improvement is validated using two populations of nitrate profiles from Biogeochemical Argo floats navigating through tropical waters. One population is from floats equipped with ISUS sensors while the other arises from floats with SUNA sensors on board. Although this model can be applied to both ISUS and SUNA nitrate sensors, it should not be used for OPUS UV nitrate sensors at this time. This new approach is similar to that used for OPUS sensors (Nehir et al., 2021, Front. Mar. Sci. 8, 663800) with differing model coefficients. This difference suggests that there is an instrumental component to the temperature correction or that there are slight differences in experimental methodologies. [ABSTRACT FROM AUTHOR]

Objective: This controlled randomized clinical trial determined the whitening efficacy and the intensity and absolute risk of tooth sensitivity in dual whitening when prefilled at‐home whitening trays were used between in‐office whitening intervals. Materials and Methods: An in‐office whitening agent containing 35% hydrogen peroxide was used. A prefilled tray with a whitening agent containing 6% hydrogen peroxide was used for at‐home whitening. Sixty‐six subjects were randomly assigned to three groups. Group I: at‐home whitening was performed 10 times between the in‐office whitening treatments. Group II: at‐home whitening was performed five times between the in‐office whitening treatments. Group III: only in‐office whitening was performed. The tooth color changes were evaluated using a spectrophotometer. A visual analog scale was used to express the pain intensity. Results: All the groups showed increased ΔE*ab, ΔE00, and ΔWID with increased whitening sessions. Group I at the 3rd whitening session showed significantly higher ΔE*ab, ΔE00, and ΔWID than group III. Tooth sensitivity showed higher values up to 24 h after whitening. Conclusions: Although dual whitening with the prefilled tray and in‐office whitening had higher whitening ability than in‐office whitening alone, the intensity and absolute risk of tooth sensitivity was similar. Clinical Relevance: The dual whitening might produce faster and stronger whitening effects than in‐office whitening alone. [ABSTRACT FROM AUTHOR]

Introduction: There is a lack of standardized tool to monitor treatment outcome of acanthosis nigricans. To meet this end, we developed the Acanthosis Nigricans Scoring Chart (ANSC) that evaluates skin color (score range of 1–8) and skin texture (score range of 1–6), which adds up to a total ANSC score (score range of 2–14). We aimed to determine the correlation of ANSC to narrowband reflectance spectrophotometry and to evaluate its reliability. Methods: A cross‐sectional study was conducted in adult acanthosis nigricans patients. Two raters independently graded participants using ANSC twice, in which scores were correlated to readings from Mexameter MX18. Intra‐ and interrater reliability were also evaluated via intraclass correlation coefficient (ICC). Results: Participants had mean (sd) melanin and erythema indices of 615.8 (176.2) and 451.4 (53.4), respectively. Mean (sd) total ANSC score was 9.43 (2.43). The total ANSC score and skin color subdomain demonstrated strong correlations (r > 0.6) with spectrophotometric results, whereas skin texture showed a moderate correlation (r = 0.4–0.6). Total ANSC score generally had excellent intra‐ and interrater reliabilities (ICC > 0.85). Conclusion: The total ANSC score and its subdomains strongly correlate with spectrophotometer and demonstrate excellent reliability in assessing acanthosis nigricans. [ABSTRACT FROM AUTHOR]

The Spectro‐Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer (SPHEREx) was selected in 2019 as a NASA Astrophysics Medium Class Explorer mission to perform the first infrared all‐sky spectral survey. The mission consists of a single wide field of view telescope mounted on top of a Ball Configurable Platform (BCP) spacecraft bus. Over the course of its two‐year mission, the SPHEREx observatory will perform four all‐sky surveys and provide spectroscopic measurements of hundreds of millions of galaxies and a diversity of astronomical phenomena. SPHEREx is currently in phase C, post‐Critical Design Review (CDR) and is in the process of building and testing hardware in preparation for observatory Assembly, Test, and Integration (AI&T) in early 2024. The observatory is expected to launch on a Falcon 9 rocket no earlier than February 2025. Project level systems engineering support is provided by the Jet Propulsion Laboratory (JPL) and oversees the technical development of the observatory and its ground operations. Systems engineers are staffed throughout all the systems and act as a key interface between the mission's many partners. This paper focuses on the systems engineering approach for the SPHEREx mission including its architecture, verification and validation methodology, and its risk and resource management approach. [ABSTRACT FROM AUTHOR]

Purpose: To compare the accuracies of three intraoral scanners for shade determination function in vitro, and to preliminarily investigate the shade‐matching characteristics of the three intraoral scanners. Materials and Methods: The shade of the middle third region of each shade tab on the Vita Classical A1‐D4 shade guide (VC) was measured with a spectrophotometer (Vita Easyshade V, VE) and three intraoral scanners, including CEREC Omnicam (OM), 3Shape TRIOS 3 (T3), and TRIOS 4 (T4). A conversion table between VC values and CIELAB values was established from the database of VE to analyze the trueness. The reproducibility of the instruments was then compared by repeating the measurements five times. Results: The mean color difference for each instrument was highest in the OM, followed by the T4, and lowest in the T3 and VE, respectively. The L* and a* value for OM, and the b* value for T4, were significantly different from those for VE (p <0.05). The reproducibility of the instrument was highest in the VE (Fleiss' kappa: 0.95), followed by the T3 (Fleiss' kappa: 0.89), T4 (Fleiss' kappa: 0.87), and OM (Fleiss' kappa: 0.78). Conclusions: Of the three intraoral scanners, the trueness was best on the T3. The reproducibility of all the instruments was excellent. [ABSTRACT FROM AUTHOR]

Objective: Few studies evaluated low concentrations of hydrogen peroxide protocols. The aim of this paper was evaluated two application protocols using 4% hydrogen peroxide in at‐home bleaching. Materials and Methods: Eighty‐six patients with upper canines' shade A2 or darker were randomly allocated under two experimental conditions: two daily applications of 1 h each or a 2‐h single application. Color change was evaluated using Vita Classical, Vita Bleachedguide, and digital spectrophotometer weekly and 1 month after the bleaching procedure through one‐way ANOVA. The risk and intensity of tooth sensitivity (TS) was assessed through visual and numeric rating scale and measured by Fisher's exact test, Mann–Whitney test and one‐way ANOVA respectively. Results: After 3 weeks, the mean difference for the ΔSGU Vita Classical (1.0; 95% CI −0.1 to 2.0), ΔEab (0.7; 95% CI −1.4 to 2.8), ΔE00 (0.1; 95% CI −1.4 to 1.6) and Wi (1.8; 95% CI ‐1.9 to 5.5) presented no difference (p > 0.08). The relative risk for TS was 0.91 (0.72 to 1.14) without significant difference neither in the risk (p = 0.6) nor in the TS intensity for both pain scales (p > 0.65). Conclusions: The application protocols evaluated (two daily applications of 1 h each or a 2‐h single application) for at‐home bleaching with 4% hydrogen peroxide did not showed differences in color change and tooth sensitivity. Clinical Relevance: Higher amount of active hydrogen peroxide in two daily applications for at‐home bleaching neither accelerate bleaching nor increase the risk or intensity of tooth sensibility. [ABSTRACT FROM AUTHOR]

Objective: Define the color of anterior teeth of a selected population and correlate it (by using coverage error [CE] and the frequency of best match) with the final color of all possible enamel‐dentine combinations of three different resin composite systems. Materials and methods: Color of 636 vital unrestored anterior teeth (central incisors, lateral incisors and canines; n = 212) and disk specimens (12 mm diameter, varying thickness) corresponding to enamel‐dentin combinations of all available enamel (0.5 mm and 1.0 mm thickness) and dentin shades (3.0 mm thickness) of Essentia, Enamel Plus HRi and IPS Empress Direct composite systems was measured using a clinical dental spectrophotometer (Spectroshade Micro). CE and frequency of best match for all composite systems were calculated for the measured in‐vivo teeth color space. Results: Natural in‐vivo teeth exhibit higher lightness when compared to enamel‐dentin composite combinations, independently of the enamel thickness used. The best (lowest) CE was found for IPS Empress, while the highest values were found for Enamel Plus Hri independently of tooth type and enamel thickness (p < 0.001). The use of 0.5 mm instead of 1.0 mm enamel thickness within enamel‐dentin composite combinations resulted in a lower CE for in‐vivo tooth color (p < 0.001). Conclusions: The color space defined by all possible enamel‐dentin combinations of the studied resin composite systems does not fully match the color range of anterior teeth. All composite systems examined lack combinations with lightness values as high as the population's. IPS Empress Direct composite system represented better the in‐vivo teeth color. Clinical significance: The use of 0.5 mm enamel shade thickness is suggested when building layered restorations, as it provided better color coverage than using 1.0 mm thickness. [ABSTRACT FROM AUTHOR]

This work explores the potential of a compact hyperspectral camera, Specim IQ, for the remote colorimetric study of polychrome surfaces in controlled environments. These measurements are generally made with dedicated instruments, such as colorimeters or spectrophotometers, which require contact with the surface and coverage areas of the order of 10s of mm2. These two characteristics, contact and a very small analysis area, can severely limit the study of polychrome surfaces, since the measured areas are not necessarily representative of the entire surface. In addition, it is not always possible to touch the objects being analyzed. A possible alternative is the use of compact hyperspectral cameras, such as Specim IQ, for the in situ study of the spectral and colorimetric characteristics of these surfaces. To better address this research, which is still in the preliminary phase, a 2 × 45°/0° geometry measuringement was used. The illumination of the image plane at 45° with respect to the camera made it possible to eliminate the components reflected specularly on the camera lens. With this shooting geometry, Labsphere Color and Gray Reflectance Standards (eight color and four gray standards) were analyzed and placed on seven different color backgrounds. With the spectral data acquired, it was possible to calculate the color of the targets and display the colorimetric values by means of three commonly used image processing software packages. In this way, it was possible to define for this hyperspectral camera a measurement‐data processing procedure applicable to measurements in the laboratory aimed at studying the color of polychrome surfaces. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to evaluate the accuracy of machine learning regression models in predicting the final color of leucite‐reinforced glass CAD/CAM ceramic veneer restorations based on substrate shade, ceramic shade, thickness and translucency. Methods: Leucite‐reinforced glass ceramics in four different shades were sectioned in thicknesses of 0.3, 0.5, 0.7, and 1.2 mm. The CIELab coordinates of each specimen were obtained over four different backgrounds (black, white, A1, and A3) interposed with an experimental translucent resin cement using a calibrated spectrophotometer. The color change (CIEDE2000) values, as well as all the CIELab values for each one of the experimental groups, were submitted to 28 different regression models. Each regression model was adjusted according to the weights of each dependent variable to achieve the best‐fitting model. Results: Different substrates, ceramic shades, and thicknesses influenced the L, a, and b of the final restoration. Of all variables, the substrate influenced the final ceramic shade most, followed by the ceramic thickness and the L, a, and b of the ceramic. The decision tree regression model had the lowest mean absolute error and highest accuracy to predict the shade of the ceramic restoration according to the substrate shade, ceramic shade and thickness. Clinical Significance: The machine learning regression model developed in the study can help clinicians predict the final color of the ceramic veneers made with leucite‐reinforced glass CAD/CAM ceramic HT and LT when cemented with translucent cements, based on the color of the substrate and ceramic thicknesses. [ABSTRACT FROM AUTHOR]

The study examines aerosol optical depth (AOD) measurements at 320 nm wavelength by a Brewer MKIII spectrophotometer located in Hobart, Australia. A climatology was developed from records encompassing the period April 4, 2002, to February 27, 2019. A methodology is described to extract cloudless episodes and cloudless half‐days. Extraterrestrial irradiances are obtained using a travelling calibration standard and are supplemented by Langley analyses on cloudless and stable half‐days. AODs are obtained by applying Beer's law to every reading and subtracting known values of ozone optical depth and Rayleigh scatter. Statistics are provided on the daily, monthly and interannual variability. Concurrent measurements from a Multifilter Rotating Shadowband Radiometer (MFRSR) operating in the visible band enabled the spectral variability of AOD to be determined. They showed the dominance of oceanic aerosols but with some input from land‐based aerosols originating mostly from biomass burning. [ABSTRACT FROM AUTHOR]

Background: To investigate the intrinsic mechanism that causes the darkening of liquid foundations. Materials and method: A total of 36 commercial liquid foundations were firstly studied for preliminary screening of influencing factors. A basic liquid foundation was developed for controlling variables to study the influence of each single factor. These samples were evenly spread on the standard opacity charts with the thickness of 100 μm and applied onto human inner forearm skin with the dosage of 2 mg/cm2. The discoloration of each sample was continuously recorded using spectrophotometers and reported in the CIE 1976 L*a*b* color space for at least 120 min, and ΔE was calculated to describe the severity of darkening. Results: One hundred twenty‐minute ΔE of all commercial foundations was highly negatively correlated with their 120‐min ΔITA° (R2 = 0.88, p < 0.01). A strong positive correlation was found between the severity of darkening and the volatilization of the basic foundations (R2 = 0.83, p < 0.01). And the darkening of silicone‐based basic foundations using pigment coating with silicon is weaker than those without silicon (p < 0.05). Conclusion: The process of the discoloration of liquid foundation is accompanied by the decrease of ITA° and manifested as darkening. The volatilization rate of the product and the coating method of the pigments used in the formula can noticeably affect the darkening of the liquid foundation. [ABSTRACT FROM AUTHOR]

Objective: Our randomized, parallel and single‐blinded clinical trial evaluated patient level of discomfort during at‐home bleaching testing the equivalence between two different protocols for the use of bleaching trays (simultaneous vs. single arch), as well as tooth sensitivity (TS), gingival irritation, (GI) and bleaching efficacy (BE). Materials and Methods: We randomized 100 patients into: simultaneous (n = 50) and single arch (n = 50). At‐home bleaching was performed with 10% hydrogen peroxide (HP) for 2 weeks for simultaneous group and 4 weeks for single arch group. We assessed patient level of discomfort using 9‐item questionnaire. The TS and GI, as well as BE using spectrophotometer and color guide were assessed using the visual analog scale (0–10). Data from level of discomfort and BE were evaluated by Student's t test. The TS and GI were compared using the relative risk and confidence interval (α = 0.05). Results: Only tray adaptation showed a significant effect after the second week (p < 0.002). There was equivalence between groups for level of discomfort (p < 0.01). We found no significant intergroup differences for the risk of TS or GI, nor for intensity. We observed no significant differences between them regarding bleaching efficacy (p > 0.21). Conclusions: A simultaneous‐use protocol for customized at‐home dental bleaching trays proved to be equivalent to using single arch for patient level of discomfort and bleaching efficacy, with no significant increase in adverse effects. Clinical Significance: Clinicians may decide whether to use a simultaneous or single arch protocol for tray usage; however, bleaching was achieved more quickly when the trays were worn simultaneously. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of layering strategy and substrate color on the masking ability of resin composites. Materials and Methods: A1‐shaded specimens from Charisma Diamond and Filtek Z350XT were produced using different layering strategies. Color measurements were made by a reflectance spectrophotometer over A2, C2, A3.5, C3, C4 substrates. Color differences were calculated and interpreted by the 50%:50% perceptibility and acceptability visual thresholds. Data was analyzed by Kruskal–Wallis and Dunn post hoc test. Chi‐square test was used to determine the association between masking ability, and independent variables. Results: Color differences were significantly lower on A2 and C2 in comparison with C4 for the majority of the layering strategies. Acceptable matches were observed on most of the combinations over A2. Moderately unacceptable mismatches were observed in most of the combinations over C2 and A3.5. Clearly unacceptable mismatches were observed on the C3 and C4. The ΔE00 color shifts were predominantly influenced by ΔL00 for all layering strategies and substrate colors. Conclusion: Masking ability was affected by the layering strategy and substrate color. Acceptable masking was associated with A2 and C2, and with layering strategy composed of 0.5 mm enamel opacity and 1.0 mm dentin opacity thicknesses, using the Filtek Z350XT. Clinical Significance: Resin composites—shade A1—applied by different layering strategies with a final thickness of 1.5 mm were able to mask mild and moderately discolored substrates. Severely discolored substrates were not masked effectively. [ABSTRACT FROM AUTHOR]

The concentration of nine heavy metals in Oreochromis niloticus inhabiting Agodi reservoir, Nigeria, was investigated. Samples were collected at the inlet, centre and outlet of the reservoir. The concentration of the metals was determined with Atomic Absorption Spectrophotometer. Ecological Risk Quotient (ERQ) was used to numerically quantify the ecological risks associated with the mineral, while Box Plot was used to evaluate the tolerance of the fish to heavy metals. The ERQ, which was in the order of Mn > Fe > Zn > Cu > Cd > Pb > Cr > Co > Ni, showed that Ni, Co, Cr and Pb had values of less than one, implying that they did not constitute an ecological threat to the environment, while Mn, Fe, Zn, Cu and Cd were of ecological risk. Results revealed that the concentration of Cd, Co and Ni exceeded the bio‐tolerance of the fish at the inlet, while Cd, Pb, Cu and Ni were beyond the tolerability of the fish at the centre. Similarly, the concentration of Co, Cu, Cr, Pb, Zn and Ni was above the tolerance limit of the fish. This showed that Fe and Mn were within the tolerance range of the fish and that the tolerability of the fish in relation to the location was inlet < Centre < Outlet. [ABSTRACT FROM AUTHOR]

Level of toxic heavy metal concentration like lead (Pb), chromium (Cr), cadmium (Cd), iron (Fe), copper (Cu), zinc (Zn), and nickel (Ni) in thirty-six soft and hard organs and their impact on lipid profile of Hypophthalmichthys molitrix and Catla catla fish species inhibiting in Tanda Dam reservoir were investigated. The heavy metal concentrations in water, sediment, and fish of the different regions in the reservoir were determined with atomic absorption spectrophotometer. Lipid profile was carried out by AOAC official methods. The results showed that Pb was dominant among all the heavy metals in six organs, and its maximum concentration of Pb (22.5 mg kg-1 and 32.9 mg kg-1) was observed in scales in Hypophthalmichthys molitrix and tail of Catla catla, respectively. The maximum concentrations of Cd were observed in the head, scales, fins, and gills of Catla catla. The bioaccumulation of heavy metals was significantly different at (p ≤ 0.01) within the organs and between the fish species. The lipid concentration was minimum in those organs where the concentrations of heavy metals were maximum. It is clear from the findings that heavy metal accumulation reduces the lipid content of fish. It is inevitable to monitor the Tanda Dam reservoir to safeguard human health. [ABSTRACT FROM AUTHOR]

In this study, a 96‐well microplates‐based spectrophotometer with the aid of the partial least squares (PLS) approach was used for the simultaneous determination of more common benzodiazepines, clonazepam, and nitrazepam, in human saliva samples. For this purpose, a hydrophobic deep eutectic solvent (DES) based on choline chloride and 1‐phenylethanol in the mole ratio of 1:4 was prepared and utilized in the ultrasound‐assisted emulsification‐microextraction (USAEME) method followed by back‐extraction to retrieve the drugs from the DES phase to 200 μL of 0.1 M NaOH solution. Central composite design (CCD) in combination with the desirability function was used for multi‐response optimization of different parameters and the optimum values were found to be: pH 2.06; DES volume, 247.1 μL; NaCl, 1.55% (w/v); sonication time, 5.33 min. The DES‐based USAEME method showed wide linear ranges of 0.1–6 and 0.2‐8 μg/mL and good limits of detection of 0.02 and 0.05 μg/mL for clonazepam and nitrazepam, respectively. Furthermore, the method was successfully used for determining the drugs in human saliva samples. [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate the exchange reaction taking place among the bovine serum albumin (BSA), 5,5 ′ -dithiobis-(2-nitrobenzoic acid (ESSE), reduced glutathione, N-acetylcysteine, D-penicillamine (thiolates), and silver metal (AgI). For this purpose, stock solutions of BSA and Ellman's reagent were prepared by dissolving 264 mg of BSA in 5 ml of reaction buffer (0.1 M KH2PO4 at pH 7.8) and 23.8 mg of ESSE in 1.0 ml of reaction buffer which were mixed together. Mixture of BSA-AgI was prepared in a separate procedure by dissolving 0.17 mg of silver nitrate in 1 ml of reaction buffer and then dissolving BSA (200 mg) in the same solution of silver nitrate. Blocking of Cys-34 of BSA with AgI was confirmed by treating different dilutions of BSA-AgI (500 μM) solutions with the solutions of ESSE (85 μM) and ES- (85 μM) and recording the spectra (300-450) with a UV-visible spectrophotometer. The chromatographed AgI-modified BSA ((BSA-S)AgI)) samples (typically 500 μM) were subsequently mixed with thiolates (reduced glutathione, N-acetylcysteine, and D-penicillamine). AgI and modified BSA (typically 500 μM each) were treated with these low molecular weight thiolates and allowed to react overnight followed by chromatographic separation (Sephadex G25). The redox reactions of AgI-modified BSA with various low molecular weight thiols revealed a mechanically important phenomenon. In the case of reduced glutathione and N-acetylcysteine, we observed the rapid release of a commensurate amount of Ellman's anion, indicating that an exchange has taken place and low molecular weight thiols (RSH) substituted AgI species at the Cys-34 of BSA eventually forming disulfide (BSA-SSR) at Cys-34. It can be anticipated from the phase of study involving bovine serum albumin that low molecular weight thiolates (reduced glutathione and N-acetylcysteine) take off AgI which are attached to proteins elsewhere in the physiological system, making these toxic metals free for toxic action. [ABSTRACT FROM AUTHOR]

Background. The aging process can induce a change in the surface microstructure of materials, the chemical compositions of matrices, and the filler particles of resin composites. This study is aimed at evaluating the effects of accelerated artificial aging (AAA) on the color change, translucency parameter (TP), and surface hardness of resin composites. Methods. Five resin composite materials (Tetric N-Ceram, Filtek Z250, Charisma Smart, Herculite Classic, and Escom100) were evaluated. A spectrophotometer was used for color measurements (L ∗ , a ∗ , and b ∗). TP and color changes (Δ E 00 ) were calculated using the CIEDE2000 formula. The resin materials were subjected to aging for 300 hours. The hardness and TP values were measured before and after AAA. One- and two-way ANOVA and the Tukey test were used. The significance level was accepted as p < 0.05. Results. Escom100 had significantly higher Δ E 00 values than the other resin composites, and Charisma Smart had significantly lower Δ E 00 values than the other tested materials (p < 0.05). Before and after AAA, Charisma Smart had the lowest TP values, and Filtek Z250 exhibited the highest hardness values (p < 0.05). For TP and surface hardness, the effect size value of the composite material was found to be higher than that of AAA. Conclusions. After AAA, the investigated resin composites had Δ E 00 values that were above clinically acceptable thresholds. After aging, the tested materials generally exhibited decreases in L ∗ values and a ∗ values, while increases in b ∗ values were observed. The ΔTP values of the resin composites were similar. AAA significantly increased the surface hardness of the tested materials. [ABSTRACT FROM AUTHOR]

The present study aimed to determine how spectrophotometer type and background blackness affect the optical evaluation of resin composites. Cylindrical specimens were built using one resin composite, provided with translucencies named Effect, Enamel, Body, and Dentin (n = 3). The CIELAB color coordinates were assessed over black and white backgrounds using a handheld spectrophotometer designed for laboratory readings (SP60, X‐Rite) and a spectrophotometer designed for clinical application (Easyshade V5, Vita Zahnfabrik). The black portion of a grayscale target (ColorChecker) and the black trap portion of the calibration reference of the spectrophotometer were used. Color differences between the devices were calculated, as well as the translucency parameter and contrast ratio. Data were analyzed by repeated‐measures ANOVA and linear regressions (α =.05). In general, Easyshade resulted in higher values for all color coordinates than the SP60, irrespective of the background. Easyshade was unable to measure the color of composite Effect over black backgrounds. For other composite translucencies, both spectrophotometers yielded similar values of translucency parameter and contrast ratio, and the blackness of the black background did not affect these results. The highest agreement for the translucency parameter and contrast ratio values was observed for the composite Dentin. High agreement was observed between the two spectrophotometers regarding the translucency parameter and contrast ratio values. However, the clinical spectrophotometer was unable to measure the color of the more translucent composite over a black background and overestimated the color coordinates. [ABSTRACT FROM AUTHOR]

The purpose of this study is to verify whether the spectrophotometer makes similar color readings when subjected to the use of biosafety barriers. Eighty specimens were made in four colors of the Llis composite resin (EA1, DA1, EA3, DA3) and four of the Filtek Z350 XT (A1E, A1D, A3E e A3D) (n = 10). The specimens were subjected to color analysis with a VITA Easyshade device according to the groups regarding the physical barrier: the protector supplied with the VITA device, polyvinyl chloride plastic film, high‐density polyethylene bag, and without protection as a control. The color difference (ΔE00) between control and groups was evaluated and compared with the perceptibility and acceptability thresholds. In the Filtek Z350 XT, there was a significant ΔE00 in color A3E, in the polyethylene bag (P <.001), and in color A1D, in the supplied protector (P =.01) in relation to the other groups. For Llis, in color EA1 for all protective barriers (P =.014), and in color DA1 only for polyethylene bag in relation to the other barriers (P =.02). ΔE00 was higher than the perceptible threshold for all groups, colors, and brands. The results below the threshold of acceptability in relation to the ΔE00 did not demonstrate consistency between barriers, colors, and resins. It was not possible to identify a statistically significant pattern of ΔE00 between the barriers. The ΔE00 were above the perceptibility threshold, and few were below the acceptability threshold. It was not possible to suggest that one biosafety barrier was superior to another or could be indicated. [ABSTRACT FROM AUTHOR]

Background. Aesthetic restorations should be able to mimic the natural colour depth of teeth, affected by several factors including material properties. There is a lack of information regarding the effect of cement shade and material thickness on the final colour of ultratranslucent multilayered zirconia veneers. Objectives. This study evaluated the effect of ceramic thickness and resin cement shade on the final colour of different layers of ultratranslucent multilayered (UTML) zirconia veneers. Methods. This in vitro study produced 90 rectangular-shaped specimens with nonsintered Katana UTML monolithic zirconia (Kuraray Noritake Dental, Tokyo, Japan), shade A1 blocks. Ceramic samples were prepared in two groups of 0.7 mm and 0.5 mm thicknesses, 45 of each (a: 8 × 11 × 0.5 mm ; b: 8 × 11 × 0.7 mm). Specimens of each thickness were further divided into 5 groups: universal, clear, brown, white, and opaque (n = 9). Each adhesive resin cement (Panavia V5) was applied between the ceramic samples and composite substrate. The colour values were measured using a spectrophotometer in baseline and after resin cement application according to the CIELab system. For all samples, Δ E 00 values were obtained. Data were evaluated with SPSS 25 using the three-way ANOVA test (p < 0.05). Results. The factors of cement shade, ceramic thickness, and ceramic layers have statistically significant effect on Δ E 00 values (p < 0.001). The results showed lower Δ E 00 values with thicker ceramic veneers. Tukey test results showed that the opaque and brown shade had a significantly greater Δ E 00 values comparing to universal (p = 0.004), clear, and white shades (p < 0.001). Conclusion. The colour change was greater in lower ceramic thickness. Different shades of resin cement and layers of UTML zirconia differently affected the final colour. [ABSTRACT FROM AUTHOR]

A simple, eco-friendly four analytical methods were established by improving the selectivity through the application of mathematical processing of UV absorption spectra for concurrent quantification of chlorthalidone (CTL) and azelnidipine (AZE). The UV absorption spectra were recorded using environment-friendly ethanol (10% v/v) and were mathematically processed using simple software provided with a UV spectrophotometer. The analytes' peak amplitude was determined using zero-crossing point first derivative spectra and ratio first derivative spectra of CTL and AZE, which were measured at 238.5 nm and 239.5 nm for CTL and 272.1 nm and 342.1 nm for AZE, respectively. The peak amplitude difference was determined from the ratio spectra of CTL and AZE by measuring the peak amplitudes at 211.8 and 267.2 nm for CTL and 328.4 and 286.1 nm for AZE. Further, ratio spectra of CTL and AZE were converted into zero-order spectra by subtracting the constant followed by multiplication with divisor spectra, and the peak amplitudes were measured at 226.9 nm and 257.3 nm for CTL and AZE zero-order spectra, respectively. Further, validation results of all the four methods confirmed the accuracy and precision of the methods by displaying good recovery (98.37–100.34%) and percentage relative standard deviation (0.397–1.758%), respectively. Good linearity was observed in the range of 1–15 μg/mL for both analytes with less than a 1 μg/mL limit of quantification. Further, the greenness and whiteness of the methods were evaluated by recently proposed AGREEness, complexGAPI, and white analytical chemistry techniques. The proposed UV spectroscopic methods were environmentally friendly, safe, economic, and effective, hence, could be used for regular quality control study of a formulation containing CTL and AZE. [ABSTRACT FROM AUTHOR]

The recent progress of machine learning and microfluidics in the chemical and biological sciences has motivated the development of new online techniques to interrogate the (bio)chemical contents within moving droplets. To accelerate the optical characterization of new materials and chemical reactions, we combine a line‐scan hyperspectral imaging system with a droplet‐based microfluidic reactor. We demonstrate the performance of this platform on a model chemistry – silver nanoparticle synthesis. The platform can image the spectral signature of ∼400 individual droplets in only 15 s, with droplet flow speeds exceeding 4 cm/s in the reaction tube. After correction of the keystone and smile effects on the hyperspectral images, the absorbance spectra are extracted from the droplets with an accuracy comparable to industrial spectrophotometers. The time evolution of the UV/Vis absorbance spectra during the reactive synthesis can be tracked either by scanning all the droplets present in the reaction tube or by following a subset of the droplet ensemble at frame rates up to 92 fps. This high‐throughput and high‐speed platform is particularly interesting for screening large parameter spaces and imaging fast reactions with a high resolution, for eventual coupling with advanced machine learning techniques to infer kinetic models and obtain detailed mechanistic insights. [ABSTRACT FROM AUTHOR]