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This work presents a comprehensive study on the dielectric properties of shellac-based composites with varying filler concentrations of (SiC) and iron (Fe) particles, complemented by scanning electron microscopy (SEM) analysis. Shellac, a natural biopolymer known for its excellent film-forming abilities, biodegradability, and insulating properties, was chosen as the matrix material. The dielectric properties, including permittivity and dielectric loss, are measured by LCR Meter across a frequency range from 100 Hz to 8 MHz to evaluate the effects of filler concentration. This study reveals that the incorporation of SiC and Fe particles significantly enhances the dielectric constant and exhibits complex frequency-dependent behavior in dielectric loss. SEM analysis provided insights into the microstructural changes induced by the fillers, correlating with the observed dielectric properties. The results indicate that the dielectric performance of shellac composites can be effectively tailored through the precise control of SiC and Fe particle concentrations, attributed to interfacial polarization and Maxwell-Wagner-sillars effects. This work underscores the potential of shellac composites as sustainable, high performance dielectric materials for advanced electronic applications, contributing to the development of eco-friendly electronic devices. [ABSTRACT FROM AUTHOR]

ZnAl2O4 and CuAl2O4 spinel nanoparticles were prepared by a modified Pechini method and used with the natural chitosan (CS) and shellac (SH) polymers to form novel composite membranes as promising food packaging materials. The selection of ZnAl2O4 and CuAl2O4 spinel nanoparticles was based on their antibacterial characteristics, availability, and economy. Using a straightforward and adaptable solution mixing and casting method, the bio-composites were created. The mechanical, physical, antibacterial, homogeneity and air permeability properties of composite films were investigated. The film structure was evaluated in terms of component interactions using FTIR spectra. The addition of 10% SH increased the tensile strength, percentage strain at maximum load, Young's modulus, and burst strength by 114–101%, 3.6–8.4, 103–119, and 179–153% for low and middle M.wt./CS respectively. Chitosan/shellac-CuAl2O4 composite has superior properties compared to ZnAl2O4 composite. In general, 0.05% spinel provides a composite having better qualities than that of 0.1 additions. Middle M.wt. chitosan provides a composite with superior properties compared to that of low M.wt. The incorporation of ZnAl2O4 or CuAl2O4 enhanced the thermal stability of the SH/CS composite. ZnAl2O4 provides superior thermal stability than CuAl2O4. When shellac/CS film structure is treated with the previously indicated ZnAl2O4 or CuAl2O4 formulation, the % swelling decreases along with an increasing in the gel fraction. The antimicrobial assessment using inhibition zone diameter and shake flask methods showed that a composite of 1:9 shellac/chitosan/0.05% of CuAl2O4 exerted the highest Gram-positive antibacterial activity against B. mycoides (21 mm), and C. albicans (22 mm). So, these enhancements make chitosan/shellac/ZnAl2O4 or CuAl2O4 composite films a good alternative to producing food packaging materials. [ABSTRACT FROM AUTHOR]

The increasing use of electronic devices raises concerns about resource availability and end‐of‐life management, particularly regarding conductors for interconnects and sensing elements. While gold and silver are the leading materials for interconnects, they pose challenges related to scarcity, cost, and toxicity. Zinc offers a promising alternative due to its good electrical conductivity, non‐toxicity, abundance, and affordability. However, challenges in achieving high conductivity and waste generation from processing techniques like screen‐printing remain. To address this, a zinc ink optimizes for 3D printing is proposed, using active zinc particles in a shellac matrix. The methods, including chemical and photonic sintering, achieve conductivities of up to 8.74•104 S m⁻¹ on paper substrates, with stable performance over a range of 30%–70% relative humidity at 15, 20, 25, and 30 °C respectively. Potential applications in high‐conductivity transducers for humidity sensing and metal‐air batteries are demonstrated, achieving a maximum power output of 3.5 mW and an open‐circuit voltage of 1.25 V. The integration of digital material assembly of zinc, reliable high‐performance operation, and non‐toxicity pave the way for innovative advancements in sustainable electronics, including applications in environmental sensing, e‐textiles, and healthcare. [ABSTRACT FROM AUTHOR]

The food of the future aims to offer several essential qualities: i) environmental respect in sourcing raw materials; ii) sustainable transformation processes; iii) enrichment with probiotic microorganisms; iv) biocompatible natural matrices. These features both enhance the nutritional value of the food and improve its pharmacological and immunological properties. When probiotics are introduced into gut in adequate densities through diet, they symbiotically promote health by boosting immune defense, producing beneficial organic molecules, and providing essential metabolic pathways for better nutrient assimilation and biotransformation. A major challenge with probiotics is their low resistance to gastrointestinal (GI) transit due to pH and other adverse hydro‐ionic conditions affecting their viability. Here, diatom microalgae (Coscinodiscus granii) is presented as a natural source of micro‐pills, functionalized with biopolymers (Shellac and Chitosan) for enteric protection, with a loading value of 71 ± 7%, higher in comparison with the loading capacity tested for two other commercial polymers. Moreover, biosilica embedded and sealed with the enteric polymers best‐protected probiotics under pH changes, and thermal and storage stresses by one‐fold more than the control probiotics without or with the lone shielding polymers. These work outcomes describe envisaging silica hybrid microcarriers obtained from living microalgae, effectively protecting probiotics in an entirely biological formulation. [ABSTRACT FROM AUTHOR]

Edible polymers are safe for consumption by humans and use in society. Shellac is a derivative of Lac, which has been used for a long time in many different industries due to its remarkable properties, which include film-forming, water resistance, thermoplastic, adhering, bonding, and simple solubility in spirit and aqueous alkali solvents. A paradigm shift has been observed in the variety of applications and uses of shellac due to the growing desire for natural products, particularly in the food, pharmaceutical, 3D printing, stealth technology, green electronics, and intelligent sensor industries. It is commonly used as an enteric coating in the pharmaceutical sector and as a preservative coating or confectioners glaze in the food industry. Being a natural and eco-friendly substance, shellac has a great deal of potential for more sustainable technologies. Due to the film's strength and polymerization, shellac, however, has limitations. The low stability and mechanical brittleness of shellac, which result from self-polymerization reactions, limit its application even though it has great potential as an environmentally benign protective covering. This review offers a comprehensive understanding of lac, encompassing its characteristics, its uses, and its prospects for the future. This study aims to investigate a new method that may mitigate some of the disadvantages of shellac coating whilst improving the material's stability and mechanical properties. [ABSTRACT FROM AUTHOR]

Abstract ZnAl2O4 and CuAl2O4 spinel nanoparticles were prepared by a modified Pechini method and used with the natural chitosan (CS) and shellac (SH) polymers to form novel composite membranes as promising food packaging materials. The selection of ZnAl2O4 and CuAl2O4 spinel nanoparticles was based on their antibacterial characteristics, availability, and economy. Using a straightforward and adaptable solution mixing and casting method, the bio-composites were created. The mechanical, physical, antibacterial, homogeneity and air permeability properties of composite films were investigated. The film structure was evaluated in terms of component interactions using FTIR spectra. The addition of 10% SH increased the tensile strength, percentage strain at maximum load, Young’s modulus, and burst strength by 114–101%, 3.6–8.4, 103–119, and 179–153% for low and middle M.wt./CS respectively. Chitosan/shellac-CuAl2O4 composite has superior properties compared to ZnAl2O4 composite. In general, 0.05% spinel provides a composite having better qualities than that of 0.1 additions. Middle M.wt. chitosan provides a composite with superior properties compared to that of low M.wt. The incorporation of ZnAl2O4 or CuAl2O4 enhanced the thermal stability of the SH/CS composite. ZnAl2O4 provides superior thermal stability than CuAl2O4. When shellac/CS film structure is treated with the previously indicated ZnAl2O4 or CuAl2O4 formulation, the % swelling decreases along with an increasing in the gel fraction. The antimicrobial assessment using inhibition zone diameter and shake flask methods showed that a composite of 1:9 shellac/chitosan/0.05% of CuAl2O4 exerted the highest Gram-positive antibacterial activity against B. mycoides (21 mm), and C. albicans (22 mm). So, these enhancements make chitosan/shellac/ZnAl2O4 or CuAl2O4 composite films a good alternative to producing food packaging materials.

In order to improve the water-resistance and ultraviolet (UV) barrier properties of pullulan (PL) film, edible composite films were prepared by solution casting based on PL and shellac (SH). The physical properties, thermal stability, mechanical properties, water vapor permeability and UV barrier of the composite films were characterized. The analysis of the functional properties revealed that the composite films had good compatibility, water-resistance (33.50˚–60.15˚), and strong UV-blocking properties (84.60%–0.00%). The addition of SH improved the water-resistance and mechanical properties of the films, but the thermal stability was slightly reduced. These films can be used as an edible coating on Chinese cherries. According to the characteristics of weight loss, decay incidence and other indicators of cherries, the PL-SH composite films can keep Chinese cherries fresh at room temperature at least for 7 days. Therefore, PL-SH composite films may be an environmentally friendly packaging material with application prospects in the fruit preservation industry.

Extraction of graphene and graphene derivatives from non‐toxic, biocompatible, eco‐friendly, and biodegradable resources with a one‐step production process is a challenge. This work is the first attempt at the one‐step graphenization of Shellac, a biopolymer derived from natural resources, achieved using direct laser patterning. Interestingly, the process highlights substrate independence by producing reduced graphene oxide (rGO) from multiple substrates, such as glass slides, Copper (Cu) adhesive tape, and overhead projector (OHP) plastic films. The produced rGO is fully characterized, and it is found that the sheet resistance is as low as 5.4., 24.65, and 8.4 Ω Sq−1. on the glass slide, OHP plastic sheet, and Cu adhesive, respectively. Moreover, developing various logos on resin‐coated ceramic tiles demonstrated the possibility of patterning desired conductive rGO patterns. Furthermore, a recyclable flexible rGO/Shellac heater is fabricated to validate its electrothermal performance (117.3 °C at 9.5 V) with foldable stability. The proposed one‐step substrate independent two‐material fabrication will revolutionize the process, potentially replacing conventional toxic routes of graphene production. [ABSTRACT FROM AUTHOR]

The present opinion deals with the re‐evaluation of shellac (E 904) when used as a food additive and with the new application on the extension of use of shellac (E 904) in dietary foods for special medical purposes. The Panel derived an acceptable daily intake (ADI) of 4 mg/kg body weight (bw) per day for wax‐free shellac (E 904) produced by physical decolouring, based on a NOAEL of 400 mg/kg bw per day and applying an uncertainty factor of 100. The Panel concluded that the ADI of 4 mg/kg bw per day should be considered temporary for wax‐free shellac (E 904) produced by chemical bleaching, while new data are generated on the identity and levels of the organochlorine impurities in E 904. This ADI is not applicable for wax‐containing shellac as a food additive. For several age groups, the ADI was exceeded at the 95th percentile in the non‐brand‐loyal exposure assessment scenario and maximum level exposure assessment scenario. Considering the low exceedance and the fact that both the exposure estimation and the toxicological evaluation of shellac were conservative, the panel concluded that the calculated exceedance of the ADI does not indicate a safety concern. The Panel recommended to the European Commission separating specifications for E 904 depending on the manufacturing process, chemical bleaching and physical decolouring, because they result in different impurities; revising the definition of the food additive to include a description of each manufacturing process; deleting information on wax‐containing shellac from the EU specifications; revising the acid value for wax‐free shellac produced by chemical bleaching; lowering the maximum limit for lead; to consider introducing limits for other toxic elements potentially present in shellac; including a maximum limit for chloroform and total inorganic chloride in the EU specification for shellac produced by chemical bleaching. [ABSTRACT FROM AUTHOR]

Lacquered brass objects are widely present in scientific and technical heritage collections. Localized atmospheric corrosion occurs on the metal when the coating fails to play its protective role. Although lacquered brass objects are not necessarily endangered by this phenomenon, the presence of dark, unpleasant corrosion spots alters the surface appearance, affecting the readability of the objects. Conservators are therefore frequently asked to clean these surfaces. We hereby present the results of a study conducted in the framework of the CleanLaB (Cleaning of Lacquered Brass) project at the Haute Ecole Arc of Neuchâtel for the cleaning of lacquered brass. This work investigates the effects of several gelled cleaning systems applied on artificially aged, lacquered brass samples to remove the corrosion products without affecting the integrity of the coating. The performance of complexing agents commonly used in conservation was compared on lacquered brass mock-ups coated with shellac resin by means of multiple non-invasive characterization and imaging techniques. The tests included conventional complexing agents like sodium citrate and disodium ethylenediaminetetraacetic acid, as well as a bio-originated system based on deferoxamine, a microbial metal chelator investigated as a green alternative in cleaning formulations.

Abstract A pipe with red coating on the surface was excavated from an archaeological site in Sweden, which is supposed to be a lacquer ware imported from China due to the admiration and pursue of lacquer wares from Asia by Europeans during sixteenth to eighteenth centuries. However, materials such as shellac and resins were often used to imitate lacquer during that time in Europe. To determine whether the pipe was Chinese lacquer ware or not, attenuated total reflection of fourier transform infrared spectroscopy (ATR-FTIR), thermally-assisted hydrolysis and methylation pyrolysis gas chromatography-mass spectrometry (THM-Py-GC/MS) were conducted. The detection of significant amount of aleuritic acid, laccijalaric acid, laccishellolic acid, shellolic acid and jalaric acid represents that shellac is the main material used for the pipe coating rather than Chinese lacquer. Long chain fatty alcohols were found in the sample, indicating that the shellac is un-dewaxed. In addition, pine resin and turpentine were also found as additives in the pipe coating. Furthermore, pigments in the coating were determined as cinnabar and carbon black by scanning electron microscopy with element energy dispersive spectroscopy (SEM–EDS) and Raman spectroscopy. The results could definitely support the conservation of the pipe, and also provide the evidence of the cultural exchange between Europe and Asia.

Lacquered brass objects are widely present in scientific and technical heritage collections. Localized atmospheric corrosion occurs on the metal when the coating fails to play its protective role. Although lacquered brass objects are not necessarily endangered by this phenomenon, the presence of dark, unpleasant corrosion spots alters the surface appearance, affecting the readability of the objects. Conservators are therefore frequently asked to clean these surfaces. We hereby present the results of a study conducted in the framework of the CleanLaB (Cleaning of Lacquered Brass) project at the Haute Ecole Arc of Neuchâtel for the cleaning of lacquered brass. This work investigates the effects of several gelled cleaning systems applied on artificially aged, lacquered brass samples to remove the corrosion products without affecting the integrity of the coating. The performance of complexing agents commonly used in conservation was compared on lacquered brass mock-ups coated with shellac resin by means of multiple non-invasive characterization and imaging techniques. The tests included conventional complexing agents like sodium citrate and disodium ethylenediaminetetraacetic acid, as well as a bio-originated system based on deferoxamine, a microbial metal chelator investigated as a green alternative in cleaning formulations. [ABSTRACT FROM AUTHOR]

Background: This review examines the application of shellac in orthodontics, focusing on its properties, advantages, and potential as an alternative to conventional materials. In orthodontics, where bond strength, ease of application, and removal are paramount, shellac's capabilities meet these needs while supporting environmentally friendly practices. Methods: With objectives centered on evaluating shellac's effectiveness, biocompatibility, and impact on patient outcomes, a comprehensive search across multiple databases was conducted, including PubMed, Scopus, and Web of Science. This study's selection criteria targeted studies assessing shellac's use in orthodontic applications, measuring treatment effectiveness, biocompatibility, and patient satisfaction while excluding those not directly involving orthodontic applications or lacking empirical data. Results: Through a qualitative synthesis of the extracted data—encompassing study design, sample size, treatment outcomes, and adverse effects—the findings reveal shellac's potential benefits in orthodontics, such as enhanced patient comfort and comparable treatment outcomes to traditional materials. However, the review also notes variability in study designs and outcomes, indicating the need for further research. Conclusions: This study concluded that shellac presents a promising alternative in orthodontic materials, recommending additional studies to standardize assessment methodologies and confirm its long-term advantages. [ABSTRACT FROM AUTHOR]

This research aims to improve the natural rubber compound (NR) for the complex rubber molding process using shellac flake from Lac as a retarder in the vulcanization process. To reduce some chemicals, steric acid which is a retarder in the vulcanization process was replaced by shellac to reduce the risk of health problems and to make the environmentally friendly. The effect of shellac on the mechanical and physical properties of rubber compounds was studied. Steric acid and shellac were mixed into five ratios as follows; 100:0, 75:25, 50:50, 25:75, and 0:100. (NR/shellac0, NR/shellac25, NR/shellac50, NR/shellac75 and NR/shellac100). Tensile strength, elongation at break, and modulus of elasticity were investigated using the Ultimate tensile test. It emerged that NR/shellac0 showed a higher modulus of elastic and maximum tensile strength than NR/shellac100 but NR/shellac0 exhibited lower viscosity, scorch time, and optimum time (tc90) than NR/shellac100. When considering NR/Shellac25, NR/Shellac50, and NR/Shellac75, it was found that scorch time (ts2), cure time (tc90), molecular weight between crosslink, maximum tensile strength, and elongation at break increased with increasing shellac ratio. On the other hand, crosslink density and modulus of elasticity decreased with increasing shellac ratio. Shellac has a large structure with hydrogen bonding between the carbonyl group and hydroxyl group in their structure so it can interrupt the mixing of shellac and zinc oxide. Consequently, the combination of stearic acid/shellac with zinc oxide (ZnO) slows down the action of the sulfur in the curing process. Compatibility of other inorganic and organic substances including the rubber molecules in the crosslinking system slowly occurred so shellac could act as an inhibitor in the curing process. However, despite this delay, the compatibility of organic and inorganic substances together with rubber molecules in the cross-linking system remained, although at a slower rate. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to enhance the functional properties of Hessian fabric through resin finishing. Hessian bags made of lignocellulosic jute fiber are commonly used to pack, store and transport agro-commodities, including horticultural crops such as rice, potato, onion and wheat. However, because of high water affinity, these bags undergo degradation in properties due to moisture release by the stored commodities themselves. Exposure to natural elements, e.g. rain and dew, also causes moisture absorption in hessian bags. Once the bag gets moistened, degradation of jute bags starts due to microbial attack, leading to loss in tensile strength and change in extensibility, leading to ultimate breakage in warp and weft directions of the fabric. Design/methodology/approach: To overcome the degradation in the functional properties of hessian fabric due to exposure to moisture and microbial attack, the application of semi-synthetic polymeric materials was carried out. Findings: Tenacity, bursting strength, puncture resistance, tear strength and breaking load, as well as life cycle of resin-treated jute fabric was found to be better than control jute. Originality/value: To the best of the authors' knowledge, no recent reports of resin finishing on jute (hessian) fabric with semi-synthetic resins are presently available, other than coating with rubber. [ABSTRACT FROM AUTHOR]

Various edible polymers [sodium alginate, carboxyl methylcellulose, sodium oleate, liquid paraffin, pectin, pullulan, polyvinyl acetate, and shellac (SHE)] as potato-coating materials and their effect on extending the shelf life of potatoes when combined with an edible coating and UV-C irradiation treatments were evaluated. As a result of the characterization of the edible polymers, SHE was selected as the optimal coating material because it had the best moisture and light barrier properties. SHE coating successfully prevented the greening, respiration, and sprouting of potatoes caused by exposure to light and oxygen. Additionally, it reduced weight loss by inhibiting transpiration on the potato surface. While the SHE coating did not exhibit antimicrobial effects, a significant effect was observed when combined with UV-C irradiation. This study suggests the potential of combined treatment of SHE coating and UV-C irradiation in extending the postharvest quality of potatoes. [ABSTRACT FROM AUTHOR]

Abstract Extraction of graphene and graphene derivatives from non‐toxic, biocompatible, eco‐friendly, and biodegradable resources with a one‐step production process is a challenge. This work is the first attempt at the one‐step graphenization of Shellac, a biopolymer derived from natural resources, achieved using direct laser patterning. Interestingly, the process highlights substrate independence by producing reduced graphene oxide (rGO) from multiple substrates, such as glass slides, Copper (Cu) adhesive tape, and overhead projector (OHP) plastic films. The produced rGO is fully characterized, and it is found that the sheet resistance is as low as 5.4., 24.65, and 8.4 Ω Sq−1. on the glass slide, OHP plastic sheet, and Cu adhesive, respectively. Moreover, developing various logos on resin‐coated ceramic tiles demonstrated the possibility of patterning desired conductive rGO patterns. Furthermore, a recyclable flexible rGO/Shellac heater is fabricated to validate its electrothermal performance (117.3 °C at 9.5 V) with foldable stability. The proposed one‐step substrate independent two‐material fabrication will revolutionize the process, potentially replacing conventional toxic routes of graphene production.

Abstract The present opinion deals with the re‐evaluation of shellac (E 904) when used as a food additive and with the new application on the extension of use of shellac (E 904) in dietary foods for special medical purposes. The Panel derived an acceptable daily intake (ADI) of 4 mg/kg body weight (bw) per day for wax‐free shellac (E 904) produced by physical decolouring, based on a NOAEL of 400 mg/kg bw per day and applying an uncertainty factor of 100. The Panel concluded that the ADI of 4 mg/kg bw per day should be considered temporary for wax‐free shellac (E 904) produced by chemical bleaching, while new data are generated on the identity and levels of the organochlorine impurities in E 904. This ADI is not applicable for wax‐containing shellac as a food additive. For several age groups, the ADI was exceeded at the 95th percentile in the non‐brand‐loyal exposure assessment scenario and maximum level exposure assessment scenario. Considering the low exceedance and the fact that both the exposure estimation and the toxicological evaluation of shellac were conservative, the panel concluded that the calculated exceedance of the ADI does not indicate a safety concern. The Panel recommended to the European Commission separating specifications for E 904 depending on the manufacturing process, chemical bleaching and physical decolouring, because they result in different impurities; revising the definition of the food additive to include a description of each manufacturing process; deleting information on wax‐containing shellac from the EU specifications; revising the acid value for wax‐free shellac produced by chemical bleaching; lowering the maximum limit for lead; to consider introducing limits for other toxic elements potentially present in shellac; including a maximum limit for chloroform and total inorganic chloride in the EU specification for shellac produced by chemical bleaching.

The paper shows the possibilities of increasing the hydrophobicity of the paper surface by applying layers of hydrophobic material to the surface. Various application techniques and the following substances were tested: stearic acid, shellac and zinc-hydroxide. Hydrophobicity was tested using the modified Cobb method, measuring the contact angle and drop retention time. The presence of hydrophobizing agents was confirmed by FTIR spectroscopy. It was found that the methods of applying the hydrophobizing agent, used in this work, give much better results with stearic acid, compared to shellac. This manuscript presents novel possibilities of increasing paper surface hydrophobicity by applying layers of hydrophobic material to the surface. Various layer application techniques were examined, as well as substances including: stearic acid, shellac and zinc-hydroxide. Hydrophobicity was tested using the modified Cobb method, measuring the contact angle and drop retention time. The presence of hydrophobizing agents was confirmed by FTIR spectroscopy. Based on the results achieved, it can be concluded that the methods of applying the hydrophobizing agent, used in this work, give much better results with stearic acid, compared to shellac.

Intragastric floating‐retention drug delivery system (IFRDDS) could effectively prolong drug‐releasing time, achieving a good clinical efficacy of encapsulated drug. In this research, the green amphiphilic resin, shellac was adopted to fabricate a continuous network as the matrix of IFRRDS by their self‐assembly behavior triggered by H+. Meanwhile, the NaHCO3 and hydroxypropyl methyl cellulose (HPMC) acted as a forming agent and a precipitating agent to control the floating behavior, respectively, which could create a porous structure for lowering the true density of the tablet and continuously absorb water to enhance the density of tablet, respectively. Interestingly, the synergistic effect of NaHCO3 and HPMC was beneficial to the initiation of the floating of the complex tablet. By regulating tablet's constitution, we could tune the floating lag time, floating time, and drug‐release behavior of the tablet. For example, the drug‐releasing curve of the shellac‐based tablet containing 3 wt% HPMC and 10 wt% NaHCO3 presented a typical linear model, which was an ideal linear drug‐releasing system, and could float in 3 min and last for 16 h. Therefore, we successfully employed a facile strategy to fabricate a biobased IFRRDS with controlled drug‐release and tunable intragastric floating‐retention properties, which has great potential for the advanced medical industry. [ABSTRACT FROM AUTHOR]

Single-fluid electrospinning creates nanofibers from molten polymer solutions with active ingredients. This study utilized a combination of a fractional factorial design and a Box–Behnken design to examine crucial factors among a multitude of parameters and to optimize the electrospinning conditions that impact fiber mats' morphology and the entrapment efficiency of Senna alata leaf extract. The findings indicated that the shellac content had the greatest impact on both fiber diameter and bead formation. The optimum electrospinning conditions were identified as a voltage of 24 kV, a solution feed rate of 0.8 mL/h, and a shellac–extract ratio of 38.5:3.8. These conditions produced nanosized fibers with a diameter of 306 nm, a low bead-to-fiber ratio of 0.29, and an extract entrapment efficiency of 96% within the fibers. The biphasic profile of the optimized nanofibers was confirmed with an in vitro release study. This profile consisted of an initial burst release of 88% within the first hour, which was succeeded by a sustained release pattern surpassing 90% for the next 12 h, as predicted with zero-order release kinetics. The optimized nanofibers demonstrated antimicrobial efficacy against diverse pathogens, suggesting promising applications in wound dressings and protective textiles. [ABSTRACT FROM AUTHOR]

The pigments consumed in grazing give the milk from dual-purpose cows raised in tropical conditions a yellowish color, affecting the quality and price of the milk. This study aimed to develop an economical method with supplementary pectin to antagonize the availability of carotenes by designing microparticles with shellac and palm oil as a viable alternative to protect pectin degradation against rumen microbes. Three preparations of microparticles based on citrus pectin were synthesized: unprotected (PnP), protected with palm oil (PwP), and protected with palm oil and shellac (PwPL) microparticles. Samples were roughly characterized by spectroscopy and electron microscopy techniques. The effect of PnP, PwP, and PwPL on blood metabolites and physicochemical characteristics of the milk of grazing lactating cows was evaluated through in vivo assays. The release of citrus pectin from microparticles was determined as uronic acids using solutions with distinct pH, whereas its degradation was studied using in situ tests. Results revealed that PnP, PwP, and PwPL are amorphous structures with sizes that range from 60 to 265 nm or 750 to 3570 µm and have surface charges that range from −11.5 to −50.2 mV. Samples exhibited characteristic peaks during FTIR analyses that corresponded to O-H, C=O, and COOCH3 groups and bands within the UV-vis region that indicated the absorption of pectin. The EDS analysis revealed the presence of carbon, oxygen, or calcium in samples. The release of uronic acids was higher at pH 2–3 with PwPL. The in situ degradability of PnP, PwP, and PwPL was 99, 28.4, and 17.7%, respectively. Moreover, PwPL decreased the blood concentration of glucose, cholesterol, and lactate. In contrast, 100 g of pectin per animal daily during the feed process reduced yellow coloring. In conclusion, designing particles protected with lipids and polymers as shellac is an economical method that resists degradation at pH levels greater than five. [ABSTRACT FROM AUTHOR]

This work aims to construct nanoparticles using different stabilizers of low-toxic natural polymers. These polymers derived from two natural substances, shellac (SH) and chitosan (CH) which formulated together by a linkage, then loaded with ampicillin. The dynamic light scattering (DLS) technique was used to calculate the size of amp-SH-CH NPs and was (60.63 ±1.87nm) with zeta potential of (+28.2 mV). The shape of amp-SH-CH NPs was evaluated using FESEM and TEM techniques. The formation SH-CH NPs loaded with ampicillin were characterized using FTIR and 1HNMR. According to the results, SH-CH NPs loaded with ampicillin can be exploited as potential Nano carriers with low toxicity and good antibacterial performance against positively and negatively bacteria. The nanocomposite's minimum inhibitory concentration (MIC) against Staphylococcus aurius and Klebsiella pneumonia was reported to be 0.001 mg.mL-1, in comparison to 0.1 mg.mL-1 for the antibiotic nonleaded ampicillin. Ampicillin loaded on shellac-chitosan nanoparticles (Amp-SH-CH NPs) have the opportunity to reduce bacterial resistance and thus increase the antimicrobial activity of ampicillin. [ABSTRACT FROM AUTHOR]

Introduction: Shellac is a known allergen present mainly in cosmetics used on the eyelids and lips, although new sources of exposure have recently been described. Our objective was to assess the use of shellac as a contact allergen in Spain and the clinical profile of patients allergic to shellac. Methods: This retrospective cross-sectional study included patients patch tested for shellac between 2018 and 2021 from the Spanish Registry of Contact Dermatitis and Cutaneous Allergy (REIDAC). Results: A total of 980 patients were patch tested for shellac (20% in ethanol), and 37 (3.77%, 95% confidence interval [CI], 2.58–3.97%) showed positive results. Most of these patients were tested for shellac due to a suspicion of cosmetic contact dermatitis. Seven patients with present relevance were found, five with relation to cosmetics, and the other two with an occupational background of food handling. The reaction index for shellac was 0.51 and the positivity ratio was 67.56% (95% CI, 52.48–82.65%). Conclusions: Shellac appears to be a prevalent allergen in patients with suspected contact dermatitis related with cosmetics or foodstuff. However, further studies are needed to validate its use in other patients. Resumen: Introducción: El shellac es un alérgeno conocido por su presencia en cosméticos para labios y párpados, aunque en los últimos años se han descrito nuevas fuentes de exposición. El objetivo de nuestro trabajo fue evaluar cómo se está usando el shellac, como alérgeno de contacto en España, y las características clínicas de los pacientes alérgicos al shellac. Métodos: Se realizó un estudio retrospectivo transversal con los pacientes incluidos en el Registro Español de Dermatitis de Contacto y Alergia Cutánea en los que se realizaron pruebas epicutáneas con shellac desde 2018 a 2021. Resultados: El shellac (20% en etanol) fue usado en 980 pacientes, con resultados positivos en 37 de ellos (3,77%; intervalo de confianza [IC] del 95%: 2,58-3,97%). La mayoría de estos pacientes realizaron las pruebas epicutáneas por una sospecha de dermatitis de contacto por cosméticos. Se encontraron 7 pacientes con una relevancia presente, 5 de ellos en relación con el uso de cosméticos, y los otros 2 fueron dermatitis de contacto ocupacionales en el contexto de la manipulación de alimentos. El índice de reacción para el shellac fue del 0,51% y la ratio de positividad del 67,56% (IC 95%: 52,48-82,65%). Conclusiones: El shellac parece un alérgeno frecuente en los pacientes con sospecha de dermatitis de contacto por cosméticos o alimentos. Sin embargo, se necesitan más estudios para validar su uso en otros pacientes.

We demonstrate in this work the practical use of uniform mixtures of a bioresin shellac and four natural clays, i.e. montmorillonite, sepiolite, halloysite and vermiculate as dielectrics in organic field effect transistors (OFETs). We present a thorough characterization of their processability and film forming characteristic, surface characterization, elaborate dielectric investigation and the fabrication of field effect transistors with two classic organic semiconductors, i.e. pentacene and fullerene C60. We show that low operating voltage of approximately 4 V is possible for all the OFETs using several combinations of clays and shellac. The capacitance measurements show an improvement of the dielectric constant of shellac by a factor of 2, to values in excess of 7 in the uniform mixtures of sepiolite and montmorillonite with this bioresin. [ABSTRACT FROM AUTHOR]

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The research aimed to dye silk satin textiles with a plant-derived colorant in the presence of additives of natural origins, such as chitosan and shellac, to investigate whether they can dye silk textiles with satisfactory results. In this study, a series of mechanical properties (Young modulus, elongation at break, and tensile strength), and colorfastness following exposure to UVC irradiation and 6 months of storage of dyed silk textiles samples were tested. Colorimetric measurements and scanning electron microscopy (SEM) images were performed and FTIR spectra were registered. Results indicated that the plant-derived colorant used in this research had the potential to dye silk satin textiles with satisfactory results. Colorant with the addition of chitosan and shellac dyed silk textiles more intensely, shellac covering ensured their color stability following UVC irradiation and during storage while the addition of chitosan did not particularly affect the color stability under the influence of UVC irradiation. However, pre-treatment with low molecular weight chitosan improves colorfastness during storage. Both additives influenced the mechanical properties of dyed silk textiles. [ABSTRACT FROM AUTHOR]

To improve and increase drug permeation efficiency and hydrogel stability, a gelatin/shellac (Gel/SL) hydrogel was prepared for use in transdermal patches. Gallic acid (Gal) was selected as a model active pharmaceutical ingredient (API). Gel/SL hydrogels were prepared with various amounts of SL (0–30% w/w SL). The swelling and permeation behavior of Gel/SL hydrogels were studied. The rigidity and hydrophobic aliphatic groups of SL affect the swelling characteristics of hydrogels, and the percentage of swelling decreases with increasing SL ratio. The permeation characteristic experiments were carried out at pH 7.4 and 37 °C for 48 h. To enhance the amount of Gal permeation, an external voltage (0–3 V) was applied. The amount of Gal permeation into tissue from Gel/SL hydrogels increased rapidly at the initial state before reaching time equilibrium, TEP (< 8 h). When a voltage was applied, the amount of Gal permeation increased due to the stronger electrorepulsive force, micro pathway generation and transappendageal route expansion. To improve the mechanical properties of the hydrogel, Gel/SL was prepared with various amounts of crosslinking agent. The physical properties and mechanical properties of the hydrogels were studied. The hardness and tensile strength were improved when the amount of crosslink agent increased due to the higher number of hydrogel strands. The amount of permeated Gal increases with decreasing amounts of crosslinking agent due to the higher free volume in the matrix. The % cell viability (of fibroblast cells) was higher than 80%. Thus, these Gel/SL hydrogels could serve as an alternative hydrogel for user-friendly and controllable transdermal patch applications. [ABSTRACT FROM AUTHOR]

The removal of aged varnish on artistic paintings is a delicate intervention and the use of UV laser for this purpose is of special relevance. In particular, the use of nanosecond-pulsed lasers operating at 213 nm has been noted to produce good results in mock-up samples, but it has not been tested in real artworks. In this paper, we report on the application of this procedure for the first time on a contemporary oil easel painting with naturally aged varnish. The obtained results were compared with those achieved using traditional solvents, specifically a mixture of ligroin:acetone. Additionally, hot water was used to remove surface dirt. The performance of the different cleaning procedures was assessed with a range of techniques, including low-power microscopy, UV lamp illumination, laser-induced fluorescence (LIF), and laser-induced breakdown spectroscopy (LIBS). Of the tested treatments, the best performance is obtained by nanosecond laser irradiation at 213 nm using an adequate laser fluence (typically 0.14 J/cm2) that allows controlled and efficient removal of the outermost aged varnish layer without affecting the underlying non-aged varnish and paint layers.

Development of new approaches for oral delivery of an existing antiviral drug aimed to enhance its permeability and hence bioavailability. Ganciclovir (GC) is an antiviral drug that belongs to class III in biopharmaceutical classification. The encapsulation of poorly absorbed drugs within nanosized particles offers several characteristics to drug due to their acquired surface properties. In the following study, the solvent evaporation technique was used to incorporate GC, within elegant nanosize particles using cyclodextrin and shellac polymers for enhancing its permeability and release pattern. Formulation variables were optimized using 23 full factorial design. The prepared formulations were assessed for yield, particle size, content, and micromeritics behavior. The optimized formula (F6) was identified through differential scanning calorimetry and Fourier transform infrared. In vitro release and stability were also assessed. Pharmacokinetic parameters of optimized nano GC solid dispersion particles (NGCSD-F6) were finally evaluated. The optimized formula (F6) showed a mean particle size of 288.5 ± 20.7 nm, a zeta potential of about 23.87 ± 2.27, and drug content 95.77 ± 2.1%. The in vitro drug release pattern of F6 showed an initial burst release followed by a sustained release over the next 12 h. The optimized formula showed accepted stability upon storage at room and refrigerator temperatures for 6 months with good flowing properties (Carr’s index = 18.28 ± 0.44). In vivo pharmacokinetic study in rabbits revealed 2.2 fold increases in the bioavailability of GC compared with commercial convention tablets. The study affords evidence for the success of the solid dispersion technique under specified conditions in improvement of bioavailability of GC.

Dentures are prosthetic devices built to imitate the function of natural teeth and are commonly produced from materials, such as metal, porcelain, and acrylic resin. Although those made from porcelain have good strength, their manufacture requires high skill and accuracy, which results in high selling price. This has led to the development of inexpensive natural biomaterials, as a suitable replacement in the dentistry field. Therefore, this study aims to explore the use of biocomposite (Bovine Hydroxyapatite (BHA)/Agave Cantula fiber/shellac) as a dental material. The mixture of BHA/Agave Cantula fiber was in various ratios, namely, 100/0, 90/10, 80/20, and 70/30 (%wt), where shellac was used as a binder at a proportion of 10% wt. The specimens were compacted at 20 bar for 10 min, and then sintered at 200°C for 2 h. The results of the FTIR test showed that the functional groups were hydroxyl, carbonate, phosphate, and methylene. Moreover, the results of the Vickers hardness test and density rate were recorded as the highest at the 30:70% variation, at (124.03 HVN) and (1,661 g/cm3), respectively. These results showed that biocomposite has the potential to be used as a dental material after further development.

The lack of biopolymer filament has been recognized as a significant challenge to fused filament fabrication (FFF) or fused deposition modeling (FDM) 3D printing. According to the restricted choice, shellac is a natural polymer of interest due to its thermoplastic property at a low temperature. The purpose of this study was to evaluate the feasibility of applying shellac as a candidate biopolymer for FFF 3D printing filaments. Shellac matrices and plasticized shellac matrices of varying grades of polyethylene glycol (PEG) were prepared using hot melt processes, and their physicochemical properties and filament properties were investigated. The results showed that a shellac matrix could be easily prepared at 80°C and stayed stable for up to 12 h. The addition of PEG could improve the stability of the shellac matrix as demonstrated by a slight deviation in acid value, percent insoluble solid, and FTIR spectra after annealing for 24 h. The shellac filaments with acceptable appearance and mechanical properties were also produced at 80 ± 5°C by the incorporation of 10–20% w/w of PEG 4000 or PEG 10000. Therefore, SHL‐PEG might be a good candidate material for the fabrication of 3D printing filament, especially at low extrusion temperature. [ABSTRACT FROM AUTHOR]

Featured Application: Design and development of smart food supplements and fortified foods for colon-targeted delivery of pre- and probiotics, nutraceuticals, and other bioactive agents. The development of food-grade carriers based on EFSA and/or FDA-approved polymeric materials is an area of growing interest for the targeted delivery of bioactive compounds to the colon. Many nutraceuticals have shown promise in the local treatment of conditions that threaten quality of life, such as ulcerative colitis, Crohn's disease, colorectal cancer, dysbiosis and other problems affecting the gut and colon. Nevertheless, their bioavailability is often limited due to poor solubility, rapid metabolism and low permeability, as well as undesirable local side effects. Encapsulation in carriers, which can protect the active ingredient from degradation and improve absorption and targeted administration in the colon, is one way to overcome these limitations. The technological characterization of these systems is important to assess their efficacy, safety and stability. In particular, morphology, size and surface properties influence their actions and interaction with the bio-phase. Meanwhile, encapsulation efficiency, profile and in vitro release kinetics are key parameters to assess the ability to reach the target site. This paper proposes a recent review of food-grade polymer-based systems for colorectal targeting of bioactive substances, focusing on their technological characterization and assessment of stability and biological activity, which are important in determining their full bench-to-bed potential. [ABSTRACT FROM AUTHOR]

The development of functional edible films is promising for the food industry, and improving the water barrier of edible films has been a research challenge in recent years. In this study, curcumin (Cur) was added to zein (Z) and shellac (S) to prepare an edible composite film with a strong water barrier and antioxidant properties. The addition of curcumin significantly reduced the water vapor permeability (WVP), water solubility (WS), and elongation at break (EB), and it clearly improved the tensile strength (TS), water contact angle (WCA), and optical properties of the composite film. The ZS–Cur films were characterized by SEM, FT-IR, XRD, DSC, and TGA; the results indicated that hydrogen bonds were formed among the curcumin, zein, and shellac, which changed the microstructure and improved the thermal stability of the film. A test of curcumin release behavior showed controlled release of curcumin from the film matrix. ZS–Cur films displayed remarkable pH responsiveness, strong antioxidant properties, and inhibitory effects on E. coli. Therefore, the insoluble active food packaging prepared in this study provides a new strategy for the development of functional edible films and also provides a possibility for the application of edible films to extend the shelf life of fresh food. [ABSTRACT FROM AUTHOR]

Resumen: Introducción: El shellac es un alérgeno conocido por su presencia en cosméticos para labios y párpados, aunque en los últimos años se han descrito nuevas fuentes de exposición. El objetivo de nuestro trabajo fue evaluar cómo se está usando el shellac, como alérgeno de contacto en España, y las características clínicas de los pacientes alérgicos al shellac. Métodos: Se realizó un estudio retrospectivo transversal con los pacientes incluidos en el Registro Español de Dermatitis de Contacto y Alergia Cutánea en los que se realizaron pruebas epicutáneas con shellac desde 2018 a 2021. Resultados: El shellac (20% en etanol) fue usado en 980 pacientes, con resultados positivos en 37 de ellos (3,77%; intervalo de confianza [IC] del 95%: 2,58-3,97%). La mayoría de estos pacientes realizaron las pruebas epicutáneas por una sospecha de dermatitis de contacto por cosméticos. Se encontraron 7 pacientes con una relevancia presente, 5 de ellos en relación con el uso de cosméticos, y los otros 2 fueron dermatitis de contacto ocupacionales en el contexto de la manipulación de alimentos. El índice de reacción para el shellac fue del 0,51% y la ratio de positividad del 67,56% (IC 95%: 52,48-82,65%). Conclusiones: El shellac parece un alérgeno frecuente en los pacientes con sospecha de dermatitis de contacto por cosméticos o alimentos. Sin embargo, se necesitan más estudios para validar su uso en otros pacientes. Abstract: Introduction: Shellac is a known allergen present mainly in cosmetics used on the eyelids and lips, although new sources of exposure have recently been described. Our objective was to assess the use of shellac as a contact allergen in Spain and the clinical profile of patients allergic to shellac. Methods: This retrospective cross-sectional study included patients patch tested for shellac between 2018 and 2021 from the Spanish Registry of Contact Dermatitis and Cutaneous Allergy (REIDAC). Results: A total of 980 patients were patch tested for shellac (20% in ethanol), and 37 (3.77%, 95% confidence interval [CI], 2.58–3.97%) showed positive results. Most of these patients were tested for shellac due to a suspicion of cosmetic contact dermatitis. Seven patients with present relevance were found, five with relation to cosmetics, and the other two with an occupational background of food handling. The reaction index for shellac was 0.51 and the positivity ratio was 67.56% (95% CI, 52.48–82.65%). Conclusions: Shellac appears to be a prevalent allergen in patients with suspected contact dermatitis related with cosmetics or foodstuff. However, further studies are needed to validate its use in other patients.

Polyacrylonitrile (PAN) films blended with shellac, biodegradable polymer, were prepared via simple solution casting method. The miscibility of PAN with shellac polymer was investigated and the optimal concentration of shellac in terms of hydrogen bonding between shellac and PAN chain was determined to be used as a novel biomass carbon precursor. Shellac and PAN chain could exert interaction and the interaction facilitates to loose the crystalline structure of the PAN chain, suggesting that the decrease of the oxidation temperature of the PAN chain in the PAN/shellac blends film by the introduction of shellac segments. The optimal PAN/shellac blends film exhibited outstanding mechanical performances (73.8% higher tensile strength, 60% higher storage modulus compared with control PAN film) showing homogeneous blending state.

Shellac and aleuritic acid manufacturing industries generate a lot of alkaline aqueous effluent during the process of manufacture of shellac and aleuritic acid from the seedlac/sticklac. The generated effluent contains lac resin, lac wax, lac dye and other water-soluble organic acids. Shellac industries in India face problems with the disposal of aqueous effluent due to the presence of considerable amounts of natural organic molecules and the dark colour solution. To address these problems, we have developed a novel method for the selective recovery of the lac resin from the alkaline aqueous effluent of shellac manufacturing industry. The recovered lac resin has been characterized by 13C-NMR, FT-IR and melting point and the data were compared with standard industrial-grade resin. The recovered lac resin was evaluated by the lac manufacturing industry for commercial applications. [ABSTRACT FROM AUTHOR]

The aim of this study was to develop bio-based adhesives that can be used for various packaging papers. In addition to commercial paper samples, papers produced from harmful plant species in Europe, such as Japanese Knotweed and Canadian Goldenrod, were used. In this research, methods were developed to produce bio-based adhesive solutions in combinations of tannic acid, chitosan, and shellac. The results showed that the viscosity and adhesive strength of the adhesives were best in solutions with added tannic acid and shellac. The tensile strength with adhesives of tannic acid and chitosan was 30% better than with commercial adhesives and 23% for combinations of shellac and chitosan. For paper from Japanese Knotweed and Canadian Goldenrod, the most durable adhesive was pure shellac. Because the surface morphology of the invasive plant papers was more open and had numerous pores compared to the commercial papers, the adhesives penetrated the paper structure and filled the voids. There was less adhesive on the surface and the commercial papers achieved better adhesive properties. As expected, the bio-based adhesives also showed an increase in peel strength and exhibited favorable thermal stability. In summary, these physical properties support the use of bio-based adhesives use in different packaging applications. [ABSTRACT FROM AUTHOR]

Increasing environmental concerns raised by the accumulation of electronic waste draws attention to the development of sustainable materials for short‐lived electronics. In this framework, printed capacitive humidity sensors and temperature resistive detectors composed exclusively of biodegradable materials: shellac, carbon‐derived particles, and egg‐albumin are reported. The sensor platform comprises interdigitated electrodes serving as a capacitive transducer for humidity sensing, and a serpentine used as a resistive temperature detector. Both the interdigitated and serpentine electrodes are manufactured by screen‐printing carbon ink on a shellac substrate. The humidity sensors are constructed by drop‐coating egg albumin on the interdigitated carbon electrodes and the temperature detector is prepared by encapsulating the serpentine design with shellac. Shellac is shown to be a biodegradable alternative to hydrophilic cellulose‐derived substrates, with the capacitive humidity sensors demonstrating a sensitivity of 0.011% RH−1. The response and recovery times on shellac are 12 and 20 times faster than on cellulose‐based substrate, and the serpentine resistive temperature detectors have a temperature coefficient of 5300 ppm K−1. At the end of their service‐life, the sensors produced are home compostable and can be environmentally friendly disposed, potentially enabling their future use for sustainable and environmentally friendly smart‐packaging, agricultural sensing, or point‐of‐care testing. [ABSTRACT FROM AUTHOR]

Due to poor barrier properties and high sensitivity to moisture, the applications of paper‐based food packaging remain limited. While gaining high barrier performance and surface durability, laminating papers with binders and other materials often leads to reduced recyclability and sustainability. Herein, we present a promising approach to improve the barrier properties and surface oil resistance of bagasse moulded pulp while preserving its green profile. A bio‐nanocomposite layer, combining nanocellulose and shellac (natural polyester), was coated on the surface of moulded pulp. This nanocomposite coating layer provides excellent gas barrier and water barrier performance simultaneously, thanks to the ester modification of nanocellulose to improve its hydrophobicity. With a good compatibility and dispersion in the shellac matrix phase, the modified nanofibrillated cellulose demonstrated an improved barrier performance compared with the unmodified nanofibrillated cellulose. Oxygen transmission rate and water vapour transmission rate of the coated pulps were in the range 60–300 cm3 m−2 day−1 and 10–30 g m−2 day−1, respectively, comparable to those of conventional food packaging materials. The surface resistance of the coated pulps was also greatly improved, indicated by the water contact angle, oil contact angle, Kit test and oil resistance test in a bowl model. The nanocomposite was able to enhance the tensile strength of the moulded pulp by 23%. In summary, the current sustainable nanocomposite coating layer demonstrated great potential in converting paper‐based materials to high barrier and sustainable food packaging. © 2022 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

Recently, terms such as sustainable, bio-based, biodegradable, non-toxic, or environment-benign are being found in the literature, suggesting an increase in green materials for various applications in the future, particularly in the packaging application. The unavoidable shift from conventional polymers to green materials is difficult, as most bio-sourced materials are not water-resistant. Nonetheless, Shellac, a water-resistant resin secreted by a lac insect, used as a varnish coat, has been underutilized for packaging applications. Here, we review Shellac's potential in the packaging application to replace conventional polymers and biopolymers. We also discuss Shellac's isolation, starting from the lac insect and its conversion to Sticklac, Seedlac, and Shellac. Further, the chemistry of shellac resin, the chemical structure, and its properties are examined in detail. One disadvantage of Shellac is that it becomes stiff over time. To enable the usage of Shellac for an extended time in the packaging application, a modification of Shellac via physical and chemical means is conferred. Furthermore, the usage of Shellac in other polymer matrices and its effect are reviewed. Lastly, the non-toxic and biodegradable nature of Shellac and its potential in packaging are explored by comparing it with traditional crude-based polymers and conventional bio-based materials. [ABSTRACT FROM AUTHOR]

The removal of aged varnish on artistic paintings is a delicate intervention and the use of UV laser for this purpose is of special relevance. In particular, the use of nanosecond-pulsed lasers operating at 213 nm has been noted to produce good results in mock-up samples, but it has not been tested in real artworks. In this paper, we report on the application of this procedure for the first time on a contemporary oil easel painting with naturally aged varnish. The obtained results were compared with those achieved using traditional solvents, specifically a mixture of ligroin:acetone. Additionally, hot water was used to remove surface dirt. The performance of the different cleaning procedures was assessed with a range of techniques, including low-power microscopy, UV lamp illumination, laser-induced fluorescence (LIF), and laser-induced breakdown spectroscopy (LIBS). Of the tested treatments, the best performance is obtained by nanosecond laser irradiation at 213 nm using an adequate laser fluence (typically 0.14 J/cm2) that allows controlled and efficient removal of the outermost aged varnish layer without affecting the underlying non-aged varnish and paint layers. [ABSTRACT FROM AUTHOR]

In-depth studies of the manufacture and composition of late nineteenth century Korean lacquerware from the Joseon dynasty are underrepresented in the English-language literature. This article, the first to offer a comprehensive layer-by-layer analysis of late Joseon dynasty lacquerware, shows that these objects are made using a mixture of traditional lacquerware techniques and materials together with new materials and methods. Through conservation and analysis of four lacquerware objects from the exhibition Mother-of-Pearl Lacquerware from Korea at the Asian Art Museum (29 April–23 October 2016), we identify the materials and techniques used in manufacture and present a new technique to allow conservators to compensate for losses of ray skin inlay. Our discovery that artists used shellac at multiple stages during manufacture calls into question the assumption that shellac was used only as a surface coating. Our findings demonstrate the material and technological complexity of Korean lacquerware from this period and can inform efforts at conservation and analysis of similar objects. [ABSTRACT FROM AUTHOR]

This study aimed to develop a Kaempferia parviflora (KP) extract based on electrospun shellac fibers capable of transporting methoxyflavones. This study used a Box–Behnken design to determine the optimal production parameters that influence the fiber diameter and bead-to-fiber ratio responses. The optimization step produced fibers with a small diameter (574 nm) and a lower bead-to-fiber ratio (0.48 beads per fiber) by combining 37.25% w/w shellac and 1.50% w/w KP extract with a solution feed rate of 0.8 mL/h and an electrical voltage of 18 kV. The KP extract was found to be dispersed throughout the electrospun shellac fibers during the characterization study. The results were highly correlated with the theoretical values, indicating that the regression models used to predict the response variables were adequate. A study of in vitro dissolution confirmed that KP extract-loaded electrospun shellac fibers could produce a sustained-release profile within 10 h. Additionally, KP-infused shellac fibers demonstrated antibacterial activity against Staphylococcus aureus. This KP loading method combined with shellac properties provided a new delivery system and could be used to explore novel biomedical materials. [ABSTRACT FROM AUTHOR]

In this paper, crude flakes (CFs) of shellac were converted into purified, nonwoven, thermospun fibers (shellac floss) using two devices, namely, an electric thermospinner (ETS) and a microwave thermospinner (MTS). This conversion was achieved by the action of heating and the centrifugal forces that arose toward the outside of the spinner-head cavity. The dissolved MTS floss was bleached using hydrogen peroxide to produce the bleached MTS floss. The unbleached shellac (CFs, ETS floss, and MTS floss) and the bleached MTS floss were characterized physically and chemically. There was no deterioration in the floss properties due to the heating tools or bleaching process. For the unbleached shellac, although there were no statistical differences in properties among the three shellac types (CFs, ETS floss, and MTS floss), except for insolubility in hot alcohol, acid value, and moisture content, the MTS floss exhibited superior values compared with the other types for nearly all the properties studied. Bleaching the MTS floss produced the greatest color change among other studies, caused a high reduction in insoluble solid matter due to increasing the solubility of some of the solid constituents of shellac, and slightly decreased its Young's modulus (E). The important dental applications were surveyed and it was suggested that the suitability was enhanced by using the bleached MTS floss, based on its superior whiteness, along with the unique properties detected. [ABSTRACT FROM AUTHOR]

Patch testing shellac in consecutive patients - Data of the Information Network of Departments of Dermatology (IVDK) 2021 Keywords: allergic contact dermatitis; cosmetics; epidemiology; patch test; shellac; tattoo EN allergic contact dermatitis cosmetics epidemiology patch test shellac tattoo 77 80 4 12/21/22 20230101 NES 230101 INTRODUCTION Shellac ("lac resin", "lacca", "gum lac", CAS: 9000-59-3) is purified by alcoholic extraction from a resin secreted by female I Laccifer lacca i (Coccidae).[1] Shellac is mainly produced in Thailand, China, Myanmar, and India and is used in a wide range of applications as a binder (e.g., in lacquers, tattoo inks), emollient (e.g., in lipstick), for hair fixing (hair spray), as a film forming agent in several types of coatings, for example, of food (E904) and oral medication, as well as thickener in cosmetics like mascara and eyeliner.[1] Terpenic acids are main constituents (~50%) of shellac without substantial variation between samples of different origin.[2] In the literature, allergic contact dermatitis to shellac was recently described from using hair spray,[3] a mouthguard,[4] tattoo ink[5] and in the occupational context of food handlers.[6] In two cross-sectional patch test (PT) studies of the North American Contact Dermatitis Group from 2009-2010 and 2011-2012, positive reactions to shellac were detected in 1.6% and 1.7% of the patients, respectively.[[7]] METHODS To investigate the diagnostic performance of the PT preparation (20% alc, Chemotechnique Diagnostics, Vellinge, Sweden) and to identify potential risk factors of sensitization, shellac was patch tested in a subset of 21 departments joining the IVDK (www.ivdk.org) in an extension of the German Contact Dermatitis Research Group (DKG) baseline series in 2021. Sixty-eight of 76 patients with positive PTs to shellac were tested with colophony, 56 with propolis, all 3 preparations in 53 patients. [Extracted from the article]

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