scholarly journals Effect of Yerba Mate and Silk Fibroin Nanoparticles on the Migration Properties in Ethanolic Food Simulants and Composting Disintegrability of Recycled PLA Nanocomposites

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1925
Author(s):  
Freddys R. Beltrán ◽  
Marina P. Arrieta ◽  
Diego Elena Antón ◽  
Antonio A. Lozano-Pérez ◽  
José L. Cenis ◽  
...  
Keyword(s):  
Silk Fibroin ◽  
Accelerated Aging ◽  
Melt Processing ◽  
Yerba Mate ◽  
Scale Level ◽  
Hydrothermal Aging ◽  
Contact Materials ◽  
Food Simulants ◽  
Before And After ◽  
Silk Fibroin Nanoparticles

The main objective of the present research is to study the effect of the incorporation of low amounts of silk fibroin nanoparticles (SFNs) and yerba mate nanoparticles (YMNs) on the migration phenomenon into ethanolic food simulants as well as on the disintegrability under composting conditions of mechanically recycled polylactic acid (PLA). Recycled PLA was obtained under simulated recycling conditions by melt processing virgin PLA into films and further subjecting them to an accelerated aging process, which involved photochemical, thermal, and hydrothermal aging steps followed by an intense washing step. SFNs were extracted from Bombyx mori cocoons and YMNs from yerba mate waste. Then, recycled PLA was melted, reprocessed, and reinforced with either 1%wt. of SFNs or YMNs, by melt extrusion, and further processed into films by compression molding. The obtained nanocomposites were exposed to ethanolic food simulants (ethanol 10% v/v, simulant A and ethanol 50% v/v, simulant D1) and the structural, thermal, and mechanical properties were studied before and after the exposure to the food simulants. The migration levels in both food simulants were below the overall migration limits required for food contact materials. The materials were disintegrated under simulated composting conditions at the laboratory scale level and it was observed that the nanoparticles delayed the disintegration rate of the recycled PLA matrix, but nanocomposites were fully disintegrated in less than one month.

scholarly journals Accelerated ageing of paper: effect of lignin content and humidity on tensile properties

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Edyta Małachowska ◽  
Marcin Dubowik ◽  
Piotr Boruszewski ◽  
Piotr Przybysz
Keyword(s):  
Tensile Properties ◽  
Ph Value ◽  
Lignin Content ◽  
Accelerated Aging ◽  
Strength Properties ◽  
Accelerated Ageing ◽  
Hydrothermal Aging ◽  
Paper Properties ◽  
Factors Affecting ◽  
Before And After

AbstractPaper degradation menaces the useful lifetime of books, manuscripts, and works on paper during storage, circulation, and display in libraries, archives, and museums. Severe damages such as embrittlement, decay, and mold often occur to the paper that might threaten to lose cultural heritage. However, the shelf life of papers stored in suitable conditions can be extended by hundreds of years. The most important external factors affecting the deterioration of paper-based materials include, in particular, changes in temperature and air humidity. In this study, the effects of accelerated aging under different conditions, including substantially different relative humidity, were considered relative to the strength properties of the paper sheets. These include the mechanical strength, such as breaking length, tear resistance, and bursting strength of the paper samples before and after dry heat aging and hydrothermal aging. Samples with various content of lignin produced in neutral pH were examined to exclude the adverse influence of acidity on paper properties. The results indicate that impact of moisture on tensile properties and pH-value of paper is much greater than the effect of increased temperature. The results of this work are intended to consolidate and expand the theoretical foundation and provide technical support for the conservators and library staff on the storage of paper cultural relics.

Assessment of Color Stability of Treated Leathers with Silicone Oil and Polyethylene Glycol

2014 ◽  
Vol 1 (1) ◽  
pp. 24-34
Author(s):  
Alireza K. ◽  
Hossein Ahmadi ◽  
Mohsen Mohammadi
Keyword(s):  
Ascorbic Acid ◽  
Polyethylene Glycol ◽  
Treatment Process ◽  
Color Change ◽  
Silicone Oil ◽  
Accelerated Aging ◽  
Color Stability ◽  
Antioxidant Additive ◽  
Before And After ◽  
Aesthetic Values

Lubricants and leather dressings are the most common treatments of dry and water logged historical leathers. Color change has a great importance during the time and treatment process, due to visual and aesthetic values of historic leather relics. Polyethylene glycol (PEG) and silicone oil (SiO) are frequently used leather dressings in the conservation procedures. Therefore, color stability of treated leathers with PEG and SiO were investigated before and after heat accelerated aging. Moreover, application of ascorbic acid was evaluated as an antioxidant additive for PEG (PEG+AA).Color change after treatment and aging were studied by colorimetry technique in the CIE *L*a*b system. Results indicated to severe color alteration in PEG treated and aged leathers with or without ascorbic acid. Whereas, SiO treated samples showed better stability and minimum color shift after aging. Silicone oil was characterized as the best dressing for historical leathers with compared to PEG and PEG+AA, due to its high stability and aesthetical properties.

scholarly journals Development and Validation of a UHPLC-qTOF MS Method for the Determination of Sorbitol-Based Nuclear Clarifying Agents in Food Simulants after Migration from Food Contact Materials

2021 ◽  
Vol 11 (9) ◽  
pp. 3789
Author(s):  
Emmanouil D. Tsochatzis ◽  
Georgios Theodoridis ◽  
Helen G. Gika
Keyword(s):  
A Posteriori ◽  
Contact Materials ◽  
Food Contact ◽  
Food Simulants ◽  
Target Analytes ◽  
Commission Regulation ◽  
Development And Validation ◽  
Migration Testing ◽  
Analytical Standards

Nuclear clarifying agents (NCAs) are a class of substances frequently used as additives in the production of polymers to improve their physical properties. Some are EU regulated under Commission Regulation (EU) no. 10/2011 can be used as additives in the production of food contact plastics. However, limited analytical methods for their analysis are currently available, in part due to poor solubility in most common organic solvents and lack of analytical standards of known purity. In this work, a simple and sensitive method was developed to analyze 4 EU-regulated sorbitol-based nucleating agents in food simulants, following solubility studies to establish effective solvents. The method was shown to be accurate and precise and can be used with official food simulant D1 (50% v/v ethanol/H2O). Application to other ethanolic simulants is also possible, but due to solubility issues, a posteriori conversion of those simulants into simulant D1 is required. Finally, the method was applied to quantify the target analytes in simulants after migration testing with polypropylene (PP) beverage cups.

scholarly journals Silk fibroin nanoparticles enhance quercetin immunomodulatory properties in DSS-induced mouse colitis

2021 ◽  
pp. 120935
Author(s):  
Patricia Diez-Echave ◽  
Antonio Jesús Ruiz-Malagón ◽  
José Alberto Molina-Tijeras ◽  
Laura Hidalgo-García ◽  
Teresa Vezza ◽  
...  
Keyword(s):  
Silk Fibroin ◽  
Silk Fibroin Nanoparticles ◽  
Immunomodulatory Properties

scholarly journals Effect of Accelerated Aging on Some Mechanical Properties and Wear of Different Commercial Dental Resin Composites

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2769
Author(s):  
Jonne Oja ◽  
Lippo Lassila ◽  
Pekka K. Vallittu ◽  
Sufyan Garoushi
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Accelerated Aging ◽  
Wear Depth ◽  
Resin Composites ◽  
Expiration Date ◽  
Dental Resin ◽  
Hydrothermal Aging ◽  
Dental Resin Composites

The aim of current in vitro research was to determine the effect of hydrothermal accelerated aging on the mechanical properties and wear of different commercial dental resin composites (RCs). In addition, the effect of expiration date of the composite prior its use was also evaluated. Five commercially available RCs were studied: Conventional RCs (Filtek Supreme XTE, G-aenial Posterior, Denfil, and >3y expired Supreme XTE), bulk-fill RC (Filtek Bulk Fill), and short fiber-reinforced RC (everX Posterior). Three-point flexural test was used for determination of ultimate flexural strength (n = 8). A vickers indenter was used for testing surface microhardness. A wear test was conducted with 15,000 chewing cycles using a dual-axis chewing simulator. Wear pattern was analyzed by a three-dimensional (3D) noncontact optical profilometer. Degree of C=C bond conversion of monomers was determined by FTIR-spectrometry. The specimens were either dry stored for 48 h (37 °C) or boiled (100 °C) for 16 h before testing. Scanning electron microscopy (SEM) was used to evaluate the microstructure of each material. Data were analyzed using ANOVA (p = 0.05). Hydrothermal aging had no significant effects on the surface wear and microhardness of tested RCs (p > 0.05). While flexural strength significantly decreased after aging (p < 0.05), except for G-aenial Posterior, which showed no differences. The lowest average wear depth was found for Filtek Bulk Fill (29 µm) (p < 0.05), while everX Posterior and Denfil showed the highest wear depth values (40, 39 µm) in both conditions. Passing the expiration date for 40 months did not affect the flexural strength and wear of tested RC. SEM demonstrated a significant number of small pits on Denfil’s surface after aging. It was concluded that the effect of accelerated aging may have caused certain weakening of the RC of some brands, whereas no effect was found with one brand of RC. Thus, the accelerated aging appeared to be more dependent on material and tested material property.

scholarly journals Formulation, characterization, and cellular toxicity assessment of tamoxifen-loaded silk fibroin nanoparticles in breast cancer

Drug Delivery ◽  
2021 ◽  
Vol 28 (1) ◽  
pp. 1626-1636
Author(s):  
Afrasim Moin ◽  
Shahid Ud Din Wani ◽  
Riyaz Ali Osmani ◽  
Amr S. Abu Lila ◽  
El-Sayed Khafagy ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Silk Fibroin ◽  
Toxicity Assessment ◽  
Cellular Toxicity ◽  
Silk Fibroin Nanoparticles

Targeted Delivery System Based on Gemcitabine-Loaded Silk Fibroin Nanoparticles for Lung Cancer Therapy

2017 ◽  
Vol 9 (37) ◽  
pp. 31600-31611 ◽  
Author(s):  
Fatemeh Mottaghitalab ◽  
Melika Kiani ◽  
Mehdi Farokhi ◽  
Subhas C. Kundu ◽  
Rui L. Reis ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Cancer Therapy ◽  
Silk Fibroin ◽  
Delivery System ◽  
Targeted Delivery ◽  
Silk Fibroin Nanoparticles ◽  
Lung Cancer Therapy ◽  
Targeted Delivery System

Bioconjugation of Neutral Protease on Silk Fibroin Nanoparticles and Application in the Controllable Hydrolysis of Sericin

2011 ◽  
Vol 59 (18) ◽  
pp. 10298-10302 ◽  
Author(s):  
Lin Zhu ◽  
Ren-Ping Hu ◽  
Hai-Yan Wang ◽  
Yuan-Jing Wang ◽  
Yu-Qing Zhang
Keyword(s):  
Silk Fibroin ◽  
Neutral Protease ◽  
Silk Fibroin Nanoparticles ◽  
Hydrolysis Of

scholarly journals Accelerated Aging Effects on Surface Hardness and Roughness of Lingual Retainer Adhesives

2008 ◽  
Vol 78 (1) ◽  
pp. 140-144 ◽  
Author(s):  
Sabri Ilhan Ramoglu ◽  
Serdar Usumez ◽  
Tamer Buyukyilmaz
Keyword(s):  
Surface Roughness ◽  
Vickers Hardness ◽  
Statistical Significance ◽  
Accelerated Aging ◽  
Aging Effects ◽  
Surface Microhardness ◽  
Halogen Light ◽  
Before And After ◽  
The Mean ◽  
Lingual Retainer

Abstract Objective: To test the null hypothesis that accelerated aging has no effect on the surface microhardness and roughness of two light-cured lingual retainer adhesives. Materials and Methods: Ten samples of light-cured materials, Transbond Lingual Retainer (3M Unitek) and Light Cure Retainer (Reliance) were cured with a halogen light for 40 seconds. Vickers hardness and surface roughness were measured before and after accelerated aging of 300 hours in a weathering tester. Differences between mean values were analyzed for statistical significance using a t-test. The level of statistical significance was set at P &lt; .05. Results: The mean Vickers hardness of Transbond Lingual Retainer was 62.8 ± 3.5 and 79.6 ± 4.9 before and after aging, respectively. The mean Vickers hardness of Light Cure Retainer was 40.3 ± 2.6 and 58.3 ± 4.3 before and after aging, respectively. Differences in both groups were statistically significant (P &lt; .001). Following aging, mean surface roughness was changed from 0.039 μm to 0.121 μm and from 0.021 μm to 0.031 μm for Transbond Lingual Retainer and Light Cure Retainer, respectively. The roughening of Transbond Lingual Retainer with aging was statistically significant (P &lt; .05), while the change in the surface roughness of Light Cure Retainer was not (P &gt; .05). Conclusions: Accelerated aging significantly increased the surface microhardness of both light-cured retainer adhesives tested. It also significantly increased the surface roughness of the Transbond Lingual Retainer.

scholarly journals Silk Fibroin Nanoparticles for Drug Delivery: Effect of Bovine Serum Albumin and Magnetic Nanoparticles Addition on Drug Encapsulation and Release

Separations ◽  
2018 ◽  
Vol 5 (2) ◽  
pp. 25 ◽  
Author(s):  
Olga Gianak ◽  
Eleni Pavlidou ◽  
Charalambos Sarafidis ◽  
Vassilis Karageorgiou ◽  
Eleni Deliyanni
Keyword(s):  
Drug Delivery ◽  
Magnetic Nanoparticles ◽  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Silk Fibroin ◽  
Bovine Serum ◽  
Drug Encapsulation ◽  
Silk Fibroin Nanoparticles
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