Significant Color Change Research Articles

Development and Evaluation of Carrot Powder-Enriched Pasta for Improved Dietary Health

Pasta is gaining popularity in the diet of an individual specially among the young. Due to increased awareness about food components for health consciousness, it is important to enhance the nutritional quality of pasta. However, the present study was designed to developed nutrient rich pasta by using carrot powder and refined wheat flour. The developed products analyzed for their nutritional quality, sensory characteristics and storability using standard procedures. It was observed that the nutritional quality of all developed enriched pasta increased significantly (p<0.05) by increasing the level of supplementation of carrot powder with refined wheat flour. In sensory characteristics evaluation it was found that there was a significant (p<0.05) difference among the formulated pastas. Results indicated CP4 (refined wheat flour 65% with carrot powder 35%) pasta higher nutritional value i.e. moisture (8.72%), ash (2.26%), crude protein (11.85%), crude fat (1.39%), crude fiber (4.43%), carbohydrate (71.35%), calcium (84.32 mg/100g), iron (3.62 mg/100g), zinc (1.25 mg/100g), magnesium (71.56 mg/100g), phosphorus (114.17 mg/100g) and potassium (626.49 mg/100g) and CP1 had higher overall acceptability than all the formulated pasta and control (100% refined wheat flour) pasta. Formulated pasta products were obtained in acceptable category even after 60th days of keeping and stored in laminated pouch which showed lower significant changes in color.

Design and Study of Azobenzene‐Modified AESO Photopolymerization Coating for Information Reversible Storage Performance

ABSTRACTThe photo‐induced cis‐trans isomerization of azobenzene molecules, known for their significant color changes, is extensively utilized in the functional modification of polymeric materials. However, the research on the functionalization of biomass‐based polyesters with azobenzene is limited. A key raw material for biomass‐based coatings possess reactive double bonds and excellent film‐forming capabilities, offering significant advantages for azobenzene functionalization in biomass‐based polyester applications. In this study, AESO served as the polyester matrix and acrylate azobenzene derivatives as the functional molecules. Under ultraviolet radiation, AESO underwent a carbon–carbon crosslinking reaction with the azobenzene derivatives to synthesize a novel resin. The coating of this resin on a PET substrate exhibited excellent pencil hardness (3B), adhesion (5B), and solvent resistance. By alternating exposure to ultraviolet and blue light, the coating displayed reversible switching between cis and trans isomers, enabling reversible writing and erasing of patterns. Even after 20 cycles of writing and erasing, high‐resolution patterns could still be observed (clearly visible under a 12x microscope). Furthermore, the image could be retained for up to 2 h under sunlight irradiation. This study presents a new method for functionalizing biobased polyesters.

Facile bio-inspired fabrication of AgNPs from Salvia elegans leaf extract and determination of their cytotoxic DNA photocleavage potential

This study introduces a sustainable method for producing silver nanoparticles (AgNPs), focusing on sustainability and environmental protection. The technique includes the use of Salvia elegans aqueous leaf extract as a reducing agent. In addition, the research investigates the dose-dependent degradation of pUC19 DNA by silver nanoparticles, which is facilitated by the generation of singlet oxygen. The presence of S. elegans extract results in significant color changes, going from a colorless state to a dark brown hue, serving as an indication of the synthesis of AgNPs. A range of experimental methods were employed to analyze the biogenic silver nanoparticles, such as UV–visible absorption spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The meticulously produced AgNPs demonstrate a high level of uniformity, featuring a spherical shape and a particle size of 60 nm. DNA photo-cleavage studies show that singlet oxygen plays a crucial role in triggering DNA damage caused by AgNPs indicates their potential as powerful cytotoxic agents specifically aimed at cancer cells. Additional studies are required to clarify the effectiveness and specificity of AgNPs against various cancer cell types to assess their therapeutic potential. The cytotoxic effects of AgNPs, particularly in relation to DNA photocleavage, are of considerable interest in cancer research. This research holds promise for developing novel and sustainable cancer therapies based on the unique properties of biogenic silver nanoparticles.

Effect of olive leaf extract on the quality of Cantal cheese

This study aimed to evaluate the impact of olive leaf extract (OLE) on the quality of Cantal cheese. The cheeses were fortified with different concentrations (Control, 1, 2, and 3 %) of OLE and analysed for quality during storage. The cheeses were evaluated on days 1, 28, and 63 for physicochemical, compositional, textural, rheological parameters, colour, microbiological analysis, and antioxidant activity. The MIR and fluorescence spectroscopies were used to study the changes in the cheese structure. A positive impact of OLE was observed on the antioxidant capacity. A mild inhibitory effect was observed against some beneficial bacteria (such as Lactococcus and Lactobacillus), while a strong inhibitory effect was found against pathogen microorganisms. No negative impact was found on the texture and chemical composition. Significant colour and structural changes were observed. The results indicate the potential of OLE to be used as bioactive ingredient to improve the quality of cheese.

PH-sensitive intelligent packaging films from Kodo millet (Paspalum scrobiculatum) starch and gum tragacanth incorporated with beetroot peel extract for monitoring shrimp freshness

This study aims to develop intelligent pH-sensitive food packaging films based on kodo millet starch (KMS), gum tragacanth (GT), and zinc oxide nanoparticles (ZNP) incorporated with betalain-rich beetroot (Beta vulgaris L.) peel extract (BPE). The physical, mechanical, optical, microstructural, thermal, barrier, and functional properties of films with different BPE concentrations (50, 100, and 200 % of dry matter weight) were studied. The results proved betalain to be the major component in the BPE, which showed significant color change under alkaline conditions. Field emission scanning electron microscopy demonstrated good compatibility among the film constituents. Fourier transform infrared spectroscopy suggested hydrogen bonding interactions between the betalain-BPE and KMS/GT/ZNP-based film matrix. Incorporating the extract at different concentrations enhanced the ultraviolet-visible light barrier, antioxidant properties, and antimicrobial properties. The betalain-rich films showed color variation from pink in an acidic medium to yellow in an alkaline medium. The film with a 200 % concentration of BPE represented the highest color change when exposed to ammonia compared to other films. During the freshness indicator study of shrimp, the total volatile basic nitrogen concentration increased. The film with a 200 % concentration of betalain extract showed visible color changes from pink to pale yellow. Overall, our results suggest that the film containing a 200 % extract concentration can be used as an active pH-responsive packaging in the food industry.

An intelligent chitosan/polyvinyl alcohol film with two types of anthocyanins for improved color recognition accuracy and monitoring fresh-cut pineapple freshness

In this study, chitosan (CS), polyvinyl alcohol (PVA), and sodium tripolyphosphate (STPP) were used as bases to introduce a blend of black wolfberry (BW) and red cabbage (RC) anthocyanins. The chelation reaction of CS, PVA, and STPP resulted in the composite anthocyanins being fixed within the matrix with an appropriate ratio of composite anthocyanins stably distributed in the film. The FTIR and X-ray analyses revealed that the addition of both types of anthocyanins strengthened hydrogen bond interactions. Moreover, the CP/BR-4 film exhibited excellent antioxidant, mechanical, and antibacterial properties, as well as a sensitive and rapid response to acidic substances. The freshness of pineapples stored under refrigeration for 6 d was also evaluated, showing more significant color changes with the CP/BR-4 film than the other treatment groups. Therefore, the composite anthocyanin film can potentially serve as an intelligent film for the detection of postharvest freshness in practical applications.

Durable colorful superhydrophobic cotton fabric constructed from modified microcrystalline cellulose prepared by Schiff base reaction

Cotton fabric is widely used for its excellent wearability but often suffers from drawbacks such as poor stain resistance, susceptibility to corrosion, and low colorfastness. Here, we introduce a novel method to create colorful superhydrophobic cotton fabric using octadecylamine-modified dialdehyde cellulose (DAC/ODA) particles as building units, which are synthesized via a Schiff base reaction and subsequently dyed with active dyes. Leveraging the film-forming ability of ODA and the affinity between cellulose materials, DAC/ODA formed a robust coating on the cotton surface, with its microstructure precisely controlled through thermal induction. The resulting fabric (DAC/ODA/Cotton) exhibited exceptional superhydrophobicity, with a water contact angle of 155° and an osmotic pressure of 426.2 mm. The uniform coverage of DAC/ODA on cotton fibers also ensured high air permeability (33.1 mm/s). Additionally, DAC/ODA/Cotton demonstrated outstanding antifouling performance against various common liquids and water can easily remove dust from its surface. Importantly, the fabric maintains its superhydrophobicity under extreme conditions such as high temperature, UV radiation, and acid-base exposure. Even after 100 abrasion cycles, no significant changes in surface morphology and color on DAC/ODA/Cotton were observed. This fluorine-free, environmentally friendly approach offers significant potential for developing multifunctional textiles and coatings with broad applications while reducing environmental impact.

An investigation on structural, morphological, thermal, optical, and antibacterial properties of chitosan-oleic acid (CH-OA) composite thin films

Recent researches show an increasing interest in developing polymer composite films to improve their properties for use in biodegradable food packaging and optoelectronic applications. For this purpose, this study aims to fabricate and characterize chitosan-oleic acid (CH-OA) composite films for different optical applications. Solution casting process was used to prepare CH-OA composite films. XRD patterns of the films showed that the addition of OA up to 3.0 % (v/w) reduced their crystalline structure. The morphology of the composites was studied using SAED and SEM. SAED patterns indicated good mixing ability between OA and CH, while SEM analysis revealed the heterogeneous surface of the films and proved the incorporation of OA into the CH matrix. The thermal stability of the films was studied using DSC and TGA analyses of the composites, and their thermograms indicated the interactions between CH and OA which improved their thermal stability. The optical properties of the films were performed in the spectral region of 250–2500 nm. The near-infrared results showed that increasing the OA concentration can lead to strong local interactions between OA and other groups in the CH matrix. The transmittance spectra of CH-OA composites at UV wavelength ≤ 400 nm showed values ​​close to 0 %, indicating that all the films have UV-blocking features. Significant changes in color and opacity parameters were detected. In the visible range (400–700 nm), the absorption coefficients, absorption indices and refractive indices of the films were evaluated. The absorption edges, Urbach energies, direct and indirect energy band gaps were in the ranges of 2.491–1.849 eV, 0.591–2.008 eV, 2.698–2.578 eV and 2.167–1.422 eV, respectively, as well as the refractive index decreased from 1.837 to 1.735 to 1.149–1.119 by increasing the OA concentration to 3.0 % (v/w). The produced composites have high optical conductivities up to 1010S−1 indicating good photoresponse and enhanced electronic excitation due to increased absorption coefficient of the film. The Wemple-DiDomenico model was used to evaluate the dispersion energies and related parameters. The values ​​of dispersion energy and oscillator energy decreased from 12.388 to 1.327 eV and 6.7268 to 5.7525 eV, respectively, with the OA content increasing to 3.0 % (v/w). The swelling degree and degradation rate were also determined and the results showed an improvement in the swelling and degradation ability of the films. The composites showed the appearance of inhibition zones indicating antibacterial activity against Bacillus cereus, Staphylococcus aureus, and Escherichia coli. These obtained results indicate that CH-OA composite films exhibited better physico-chemical properties with significant improvement and thus can be used in biodegradable food packaging and optoelectronic devices.

Mesalamine loaded ethyl cellulose nanoparticles: optimization and in vivo evaluation of antioxidant potential in ulcerative colitis

This study aimed to optimize mesalamine (MES)-nanoparticles (NPs) using Box Behnken Design and investigate itsin vivoantioxidant potential in colon drug targeting. The formulation was prepared using oil/water (O/W) emulsion solvent evaporation technique for time dependent colonic delivery. The optimal formulation with the following parameters composition was selected: polymer concentration (% w/w) (A) = 0.63, surfactant concentration (% w/w) (B) = 0.71, sonication duration (min) (C) = 6. The outcomes showed that ethyl cellulose (EC) NP containing MES has particles size of 142 ± 2.8 nm, zeta potential (ZP) of -24.8 ± 2.3 mV, % EE of 87.9 ± 1.6%, and PDI of 0.226 ± 0.15. Scanning electron microscopy revealed NPs has a uniform and spherical shape. Thein-vitrorelease data disclosed that the EC NPs containing MES showed bursts release of 52% ± 1.6% in simulated stomach media within 2 h, followed by a steady release of 93% ± 2.9% in simulated intestinal fluid that lasted for 48 h. The MES release from NP best match with the Korsmeyer-Peppas model (R2= 0.962) and it followed Fickian diffusion case I release mechanism. The formulation stability over six-months at 25 °C ± 2 °C with 65% ± 5% relative humidity, and 40 °C ± 2 °C with 75% ± 5% relative humidity showed no significant changes in colour, EE, particle sizes and ZP. As perin vivoresults, MES-NP effectively increased glutathione, SOD level and reduces the LPO level as compared to other treatment groups. The findings hold promise that the developed formulation can suitably give in ulcerative colitis.

Flexural strength, surface roughness, and color stability of various CAD-CAM denture teeth materials.

To assess the flexural strength (FS), surface roughness, and color stability of additive manufactured (AM) and subtractive manufactured (SM) denture teeth materials, as well as the effect of thermocycling on these properties. Eighty strips (20/material type; 64×10×3.3mm) and 60 discs (15/material type; 12×4mm) were fabricated from four different denture teeth materials (Straumann, Flexcera, Ivoclar, and Candulor). The specimens were divided into two subgroups (nonthermal cycled and 5000 thermal cycled,10 per subgroup), and subjected to a 3-point test for FS using a universal testing machine at a crosshead speed of 5.0mm/min. Surface roughness (Ra, µm) and color differences (ΔE00) of disc specimens were measured before and after thermocycling using a noncontact optical profilometer and a spectrophotometer, respectively. The CIEDE2000 formula was used to calculate the color differences (ΔE00) before and after thermocycling. Data were analyzed using 2-way ANOVA followed by post hoc multiple comparison tests (α=0.05). There was no significant difference in flexural strength between nonthermal cycled SM materials (p=0.15), which were significantly higher than AM materials (p<0.001). The flexural strength values of all tested materials weresignificantly reduced after thermocycling (p<0.05). The material type had a significant effect on the Ra values (p<0.001), whereas thermocycling did not (p=0.81). After thermocycling, all materials exhibited color changes lower than the clinical perceptible threshold (ΔE00=2.7). Thermocycling decreased the FS of denture teeth materials manufactured with AM and SM, but did not affect the surface roughness. The FS values of SM groups were significantly higher than AM materials, irrespective of thermocycling. No clinically significant color changes of the denture teeth material were noted.

Assessment of Packaging Materials for Bulk Packaging of Mustard

A study was conducted to develop effective bulk packaging solutions for mustard, focusing on testing various packaging materials with liners and analysing shelf life for export purposes. To maintain the quality of spices, it is crucial to have oxygen and gas barrier properties to preserve aroma. To address this, a novel liner combination has been introduced to evaluate its effectiveness in extending the shelf life of mustard. Mustard was packed in nine types of packaging materials selected based on sustainability aspects and subjected to accelerated climatic conditions (38±1°C and 90±2% RH) for six months. Physico-chemical parameters were measured in triplicate. Throughout the exposure period, moisture content and water activity in the mustard increased exponentially. Significant changes in colour, aroma, and microbial growth were observed in samples packaged in PP woven bags without liners and multiwall paper bags. However, no damage to the packaging materials was noted during transport testing. The maximum shelf life was recorded for mustard packed in PP woven bags with liners and multiwall paper bags with aluminium foil. Hence, the results indicated that exploring advanced liner combinations can significantly enhance the shelf life and maintain the quality of mustard.

Investigating the Effect of Polyetheretherketone (PEEK) Veneers on Bond Strength and Discoloration When Repairing Various Composites.

This study aimed to examine the impact of the strength and color change of composite materials that could be utilized in the repair of polyetheretherketone (PEEK) veneer fractures. The 220 nanoceramic-filled PEEK specimens used in the study were divided into four groups, and color measurements were made on a gray background (n=55): Group N, 1-mm-thick monochromatic composite; Group NN, 2-mm-thick monochromatic composite; Group F, 1-mm-thick 2-mm-diameter short fiber-reinforced composite, placed in the center and polymerized; and Group FF, 2-mm-thick 2-mm-diameter short fiber-reinforced composite, placed in the center and polymerized. The remaining mating surfaces were restored by filling with monochromatic composite and adhesion strength testing by re-measuring the color. The results of the two-way ANOVA indicated that there was a significant color change caused by both thickness and composite type (p<0.001). Additionally, a significant difference in bond strength was observed between the groups. In PEEK restorations, short fiber-reinforced composites significantly increase bond strength, while the use of monochromatic composites of a certain thickness ensures that color change remains within acceptable limits. Although PEEK has a superior mechanical structure, it does not meet the aesthetic expectations and needs to be veneered. However, fractures are frequently seen due to low bond strength. Therefore, this study is important because it aims to provide guidance to clinicians on aesthetic and mechanical methods that can be used in PEEK prosthesis repair.

Tuning the reversible mechanochromic luminescence of triphenylethylenes by rational introduction of functionalized thiophenes substituents

Four triphenylethylene derivatives have been designed and synthesized in this work. Compared to traditional tetraphenylethene (TPE) compounds, it was found that the obtained compounds could exhibit potential isomerism in chemical and spatial structures due to their unique asymmetry, which revealed that the subtle structural changes directly influence the packing modes of the compounds in aggregated state, tuning their mechanochromic luminescence properties. Moreover, the emission wavelength of mono-substituted triphenylethylene derivatives showed a blue-shift trend when stimulated by external mechanical forces. After fuming or recrystallization, they can recover to long-wavelength emission. Among them, compound TTC-2 exhibited the most significant color changes and the largest wavelength variation.

Citric acid functionalized neomycin carbon dots for cytotoxicity and sensing application

Carbon nanomaterials have been applied in various fields. Currently, functionalized carbon nanomaterial with practical tuning and surface functionalization is a tremendously used method. Herein, neomycin-based fluorescent carbon quantum dots were synthesized via hydrothermal method using neomycin and citric acid as a source for selective sensing of Fe3+ metal ions. The as-prepared Neo-CA-CQDs exhibited blue fluorescence, successfully characterized and utilized for sensing various metal ions. The carbon dots showed excellent sensing properties towards Fe3+ metal ions and optical properties were characterized by a fluorescence spectrofluorometer. In addition, pH and biocompatibility studies were investigated for the Neo-CA-CQDs. The average size of the Neo-CA-CQDs was 3–5.7 nm. The quantum yield of the as-prepared Neo-CA-CQDs was 29.3 %. The limit of detection for Fe3+ sensing was determined to be 6.09 μM. The sensing of Fe3+ ions was also confirmed through visual detection, as a significant color change of the CQDs was observed. Additionally, a competitive study was conducted to verify the selectivity of the neomycin citric acid-mediated CQDs towards Fe3+. The in vitro cytotoxicity study was performed on a mouse fibroblast cell line (L929) and Human cervical cancer cell line (HeLa).

Functionalization of cellulose by facile Dissolution-Regeneration in A novel CS2/DBU/DMSO solvent system for detection of metal ions and antibacterial

The high value-added utilization of cellulose with various functions is a hot topic in the field of bio-based materials. The existing high value-added utilization methods mainly rely on the dissolution and functionalization of cellulose in two steps in a homogeneous system. Herein, a new CS2/DBU/DMSO solvent system was successfully designed by combining viscose and CO2 switchable solvent, and then obtained regenerated product (DCC) with metal ion detection and antibacterial functions through a simple process from dissolution to regeneration. Cellulose dissolves mildly and efficiently in this system. In addition, the metal ion test paper prepared from DCC can quickly respond to Co2+, Cu2+, and Fe3+ ions and produce significant visual color changes in a short period of time. Finally, the experiment showed that the DCC film has good antibacterial activity against S. aureus and E. coli. This study lays the foundation for the dissolution, derivation, and processing of cellulose, and provides new ideas for the production of functional materials using cellulose in the future.

Tailoring the Optical and Color Properties of Gamma Irradiated Polycarbonate/Cerium Oxide Nanocomposite Films for Their Application in Optoelectronic Devices

Nanocomposites (NC) of amorphous polycarbonate (PC) and cerium oxide (CeO2) nanoparticles (NPs) were prepared. The synthesized CeO2 had a nanonature of average particle size 22 nm, as indicated from their high resolution transmission electron microscopy images (HTEM). Samples of the PC/CeO2 NC films were irradiated with several γ ray doses (10-80 kGy). The resultant outcome of the γ irradiation on the optical properties of the NC films was studied using ultraviolet spectroscopy (UV-vis). Upon raising the γ ray dose up to 80 kGy, the maximum dose used, the direct bandgap decreased from 4.92 to 3.91 eV. The Urbach energy showed an opposite trend; it increased from 0.46 to 0.92 eV. This could be attributed to the domination of chain crosslinks. Also, the optical dielectric loss (ε”) assisted in identifying the nature of the microelectronic transitions. It was found that the PC/CeO2 NC films had direct allowed transitions. Additionally, the γ induced changes in the optical conductivity were studied. Moreover, the optical color changes between the pristine and the irradiated films were evaluated. The pristine NC film was uncolored. It showed significant color changes when irradiated with γ radiation up to 80 kGy. The induced modifications in the optical properties suggest that the γ radiation is an effective means for modifying the properties that allows the use of PC/CeO2 NC in optoelectronic devices.

Inactivation of foodborne pathogens on fruit juice with different solid contents by using pilot-scale 915 MHz microwave heating system

Fruit juices are often distributed in the form of concentrate for the sake of quality conservation and cost-reduction during distribution. The objective of this study is to investigate the effect of solid content on heating rate, dielectric properties, and foodborne pathogen inactivation in fruit juices when subjected to 915 MHz microwave heating. 50 mL of fruit juice with different solid contents were exposed to 915 MHz microwave at 3.0 kW for up to 60 s. Solid content was found to be an important factor for heating rate. The fastest heating rate was observed when concentrates were diluted by 50% (36 ° Brix apple and 30 °Brix orange juice). Though dielectric constant decreased along with increase in solid contents, different trends were observed for the dielectric loss factor. Especially, the fruit juices with higher magnitudes of the dielectric loss factor presented faster heating rate. Inactivation of the pathogens inoculated in the fruit juices was investigated by using E.coli O157:H7 and L.monocytogenes. In case of apple juice, 915 MHz microwave heating was most effective for 72 °Brix as 20 s operation resulted in over 5-log reduction for both pathogens. However, in orange juice, 30 °Brix was found to be most effective for 915 MHz microwave heating. In the inactivation mechanism analysis, cell membrane damage was observed when cells were exposed to higher solid contents due to low water activity. 915 MHz microwave heating did not include significant quality changes in terms color and total phenolic contents, except for 60 ° Brix of orange juice. The obtained results highlight the potential application of 915 MHz microwave heating for fruit juice processing

Selection of novel ssDNA aptamer for ultra-sensitive colorimetric detection of acetamiprid using ultra-small dot assay

An innovative ssDNA aptamer-mediated colorimetric biosensor utilizing an ultra-small dot assay has been developed for the ultra-sensitive detection of acetamiprid, a hazardous insecticide widely used in agriculture. This “Dot assay” leverages ultra-low volumes of less than 20 µL, allowing for rapid visual detection within seconds and addressing the urgent need for accessible and efficient detection methods. Through a non-immobilized graphene oxide-based systematic evolution of ligands by exponential enrichment (SELEX) approach, a specific 79-mer aptamer (Apt-SS5) was identified after 15 enrichment cycles. The Apt-SS5 aptamer demonstrated a remarkable binding affinity for acetamiprid, with a melting temperature (Tm) of 53 °C and a Gibbs free energy (ΔG) of −7.24 kcal/mol at 37 °C. Notably, the binding pocket is formed by nucleotides C-16 to T-32, with critical interactions occurring at C-10, C-16, G-25, A-26, G-27, G-28, and A-29. The optimized colorimetric assay achieved an impressive limit of detection (LOD) of 0.039 ppb and resulted in a significant reduction in assay costs. The target specificity and cross-reactivity of Apt-SS5 were tested against other pesticides, including imidacloprid, thiachloprid, thiamethoxam, chlorpyrifos, pyriproxyfen, and chlorantraniliprole, with no significant color change observed for these non-targets. In contrast, a clear visual color change was noted in the presence of acetamiprid, confirming the aptamer’s high specificity. Additionally, the aptasensor proved effective for testing river and water samples, yielding recovery rates of 84.40 % to 101.66 %. This innovative approach enhances sensitivity and simplifies the detection process, paving the way for rapid screening of pesticide residues in various samples.

The Effect of Hybrid Nano Addition on the Color Stability of Maxillofacial Rehabilitation Silicone Material after Weathering

Abstract Background: Facial prostheses may get discolored and change color from intrinsic and extrinsic coloring due to external factors. This is related to the inherent color stability of elastomers and colorants. Objectives: We aimed to evaluate the effect of hybrid nano additives on the color stability of Tech-Sil25 room-temperature vulcanized silicones used for maxillofacial prosthesis after artificial weathering. Materials and Methods: A total of 70 samples were fabricated for fourteen groups. Seven groups contained 0.2 wt% burnt sienna, and another seven groups contained 0.2 wt% cobalt blue. The seven groups were the control groups. Each group consists of five samples. The samples were exposed to artificial weathering for 300 h. The CIELAB color system was used to record the color values. It aids in the numerical classification of color differences by describing the three color coordinates (or color values) x, y, and z in three unique corresponding values of L, a, and b, respectively. Results: Burnt sienna pigment samples with hybrid nano 1%NS+1%NA show the highest color stability, followed by 2% NS and 2% NA; the least color change was observed (ΔE* about = 1.1) by the visual system as the threshold was seen. The cobalt blue pigment shows the most significant color change. The color shift observed in all groups was within the clinically acceptable level. Conclusion: It can be concluded that a 2% hybrid nano additive can improve the color stability for both pigment groups (burnt sienna and cobalt blue). The variation in color in the burnt sienna group was less than that in the cobalt blue groups. The color change in each group came within an acceptable range for clinical purposes.

Stability of Antibiotics for Use in the Testing of Immediate Drug Allergy Reactions

BackgroundLimited information is available regarding the physicochemical stability of penicillins-based preparations for skin testing purposes and no information is currently available for other classes of antibiotics. ObjectiveTo perform chemical and physical stability studies on 16 parenteral antibiotics for skin testing purposes, with an overall aim to provide practical recommendations to clinicians on suitable components, storage, and optimal shelf-life of such preparations. MethodsChemical stability was assessed via validated stability-indicating high performance liquid chromatography with ultraviolet detection assays, while absence of precipitations or haziness, significant pH shift and colour change were used to determine physical stability. ResultsOther than amoxicillin/clavulanic acid, all of the parenteral antibiotics were found to have adequate physicochemical stability between 2 to 7 days. Amoxicillin in Water for Injection BP retained >90% stability, while amoxicillin/clavulanic acid dropped to <80%. Ampicillin remained >90% stable for 2 days, and benzylpenicillin, flucloxacillin, and piperacillin/tazobactam were stable for ≥2 days at ∼95%. Cephalosporins were stable for 2 days, except ceftazidime, which increased to >110%. Aztreonam, ciprofloxacin, and vancomycin retained >95% stability for 7 days, while meropenem was stable for 2 days. Sulfamethoxazole/trimethoprim lost 15% but stabilized at ∼85% for 7 days. No precipitation occurred, but amoxicillin/clavulanic acid changed colour by day 7. pH decreases of ≤1.0 unit were observed in penicillins, while cefepime dropped below acceptable pH limits by day 7. Absorbance shifts >100 units were seen in several antibiotics by day 7. ConclusionsThis study has generated practical stability information for clinicians, allowing 15 parenteral antibiotics from 7 different classes to be aseptically prepared in advance for use in the testing of drug allergy reactions.