Dissolution and Enzymatic Degradation Studies Before and After Artificial Ageing of Silk- or Linen-Reinforced Gelatin Laminates, 1

2003 ◽  
Vol 288 (5) ◽  
pp. 399-406 ◽  
Author(s):  
M. Boyanova ◽  
N. Stambolieva ◽  
A. A. Apostolov ◽  
S. Fakirov
Keyword(s):  
Enzymatic Degradation ◽  
Artificial Ageing ◽  
Before And After ◽  
Degradation Studies

scholarly journals Characterization and Identification of Varnishes on Copper Alloys by Means of UV Imaging and FTIR

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 298
Author(s):  
Miriam Truffa Giachet ◽  
Julie Schröter ◽  
Laura Brambilla
Keyword(s):  
Copper Alloys ◽  
Analytical Techniques ◽  
Experimental Methodology ◽  
Artificial Ageing ◽  
Non Invasive ◽  
Uv Imaging ◽  
Before And After ◽  
The Comparative Study ◽  
The 19Th Century ◽  
Analytical Tools

The application of varnishes on the surface of metal objects has been a very common practice since antiquity, both for protective and aesthetic purposes. One specific case concerns the use of tinted varnishes on copper alloys in order to mimic gilding. This practice, especially flourishing in the 19th century for scientific instruments, decorative objects, and liturgical items, results in large museum collections of varnished copper alloys that need to be preserved. One of the main challenges for conservators and restorers deals with the identification of the varnishes through non-invasive and affordable analytical techniques. We hereby present the experimental methodology developed in the framework of the LacCA and VERILOR projects at the Haute École ARC of Neuchâtel for the identification of gold varnishes on brass. After extensive documentary research and analytical campaigns on varnished museum objects, various historic shellac-based varnishes were created and applied by different methods on a range of brass substrates with different finishes. The samples were then characterized by UV imaging and infrared spectroscopy before and after artificial ageing. The comparative study of these two techniques was performed for different thicknesses of the same varnish and for different shellac grades in order to implement an identification methodology based on simple non-invasive examination and analytical tools, which are accessible to conservators.

scholarly journals Transformation Mechanisms of Chemical Ingredients in Steaming Process of Gastrodia elata Blume

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3159 ◽  
Author(s):  
Yun Li ◽  
Xiao-Qian Liu ◽  
Shan-Shan Liu ◽  
Da-hui Liu ◽  
Xiao Wang ◽  
...  
Keyword(s):  
Enzymatic Degradation ◽  
Chemical Constituents ◽  
Relative Content ◽  
Ester Bond ◽  
Gastrodia Elata ◽  
Before And After ◽  
Transformation Mechanisms ◽  
First Time ◽  
Hydroxybenzyl Alcohol ◽  
Tof Ms

To explore the transformation mechanisms of free gastrodin and combined gastrodin before and after steaming of Gastrodia elata (G. elata), a fresh G. elata sample was processed by the traditional steaming method prescribed by Chinese Pharmacopoeia (2015 version), and HPLC-ESI-TOF/MS method was used to identify the chemical composition in steamed and fresh G. elata. Finally, 25 components were identified in G. elata based on the characteristic fragments of the compounds and the changes of the 25 components of fresh and steamed G. elata were compared by the relative content. Hydrolysis experiments and enzymatic hydrolysis experiments of 10 monomer compounds simulating the G. elata steaming process were carried out for the first time. As a result, hydrolysis experiments proved that free gastrodin or p-hydroxybenzyl alcohol could be obtained by breaking ester bond or ether bond during the steaming process of G. elata. Enzymatic experiments showed that steaming played an important role in the protection of gastrodin, confirming the hypothesis that steaming can promote the conversion of chemical constituents of G. elata—inhibiting enzymatic degradation. This experiment clarified the scientific mechanism of the traditional steaming method of G. elata and provided reference for how to apply G. elata decoction to some extent.

scholarly journals Microleakage at enamel and dentin margins with a bulk fills flowable resin

2014 ◽  
Vol 08 (01) ◽  
pp. 001-008 ◽  
Author(s):  
Nicola Scotti ◽  
Allegra Comba ◽  
Alberto Gambino ◽  
Davide Salvatore Paolino ◽  
Mario Alovisi ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Resin Composite ◽  
In Vitro Study ◽  
Artificial Ageing ◽  
Resin Composites ◽  
Class V ◽  
Dye Penetration ◽  
Before And After ◽  
Blue Solution

ABSTRACT Objective: The aim of this in vitro study was to evaluate the marginal sealing ability of a bulk fill flowable resin composite on both enamel and dentin substrates. Materials and Methods: 48 non-carious molars were selected and four Class-V cavities were prepared at the CEJ of each sample. Cavities were filled with Venus Diamond (Heraeus Kulzer); Venus Diamond Flow (Heraeus Kulzer) and Surefil SDR (Dentsply). Samples were divided into two groups: First group samples were immersed in a methylene blue solution for 30 min at 25°C. Second group samples were artificially aged and then treated with methylene blue. Samples were sectioned in the center of the restoration and observed with a 40x stereomicroscope, and the percentage of cavity infiltration was calculated. Results: Results were analyzed statistically by ANOVA (P < 0.05). The amount of infiltration was significantly lower for the enamel substrate compared with dentin (P = 0.0001) and in samples immediately immersed in methylene blue compared with those that were artificially aged (P = 0.011). The interaction between the composite material and the marginal substrate significantly affected dye penetration (P = 0.006). Conclusions: Bulk fill flowable resins provided significantly better marginal seal in dentin, both before and after artificial ageing. Nanohybrid resin composites and bulk fill flowable resins showed similar microleakage values at enamel margins. Bulk fills flowable resins provided significantly better marginal seal in dentin, both before and after artificial ageing. Nanohybrid resin composites and bulk fill flowable resins showed similar microleakage values at enamel margins.

Segmented Polyurethanes for Medical Applications: Synthesis, Characterization andin vitro Enzymatic Degradation Studies

2001 ◽  
Vol 169 (1) ◽  
pp. 261-272 ◽  
Author(s):  
Gianluca Ciardelli ◽  
Alfonsina Rechichi ◽  
Piero Cerrai ◽  
Mario Tricoli ◽  
Niccoletta Barbani ◽  
...  
Keyword(s):  
Enzymatic Degradation ◽  
Medical Applications ◽  
Segmented Polyurethanes ◽  
Degradation Studies

Hydrolytic and enzymatic degradation studies of aliphatic 10-undecenoic acid-based polyesters

2018 ◽  
Vol 155 ◽  
pp. 84-94 ◽  
Author(s):  
Carmen Valverde ◽  
Gerard Lligadas ◽  
Juan C. Ronda ◽  
Marina Galià ◽  
Virginia Cádiz
Keyword(s):  
Enzymatic Degradation ◽  
Degradation Studies ◽  
Undecenoic Acid

scholarly journals Preventing the Undesired Surface Veiling after Nanolime Treatments on Wall Paintings: Preliminary Investigations

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1083
Author(s):  
Teresa López-Martínez ◽  
Jorge Otero
Keyword(s):  
Ethylenediaminetetraacetic Acid ◽  
Significant Advance ◽  
Artificial Ageing ◽  
Wall Paintings ◽  
Chemical Cleaning ◽  
Conservation Practice ◽  
Before And After ◽  
Non Destructive ◽  
Mechanical Cleaning ◽  
Destructive Methods

During the last decades, the discovery of nanolime and its introduction in the field of Cultural Heritage has entailed a significant advance for the consolidation of historic wall paintings. Nevertheless, its use is not completely generalized yet within the conservation practitioner’s community due to its undesired white veiling deposit on the surface after treatment which usually covers the pictorial layer. Given the scarcity of existing literature which specify how to mitigate this undesired side-effect, the aim of this work is to carry out the first assessment of possible cleaning and treatment methods to eliminate those deposits and, at the same time, to analyse their effects on the consolidation properties. To do that, we have developed laboratory fresco wall paintings specimens. After applying an artificial ageing cycle to all of them, we consolidated them with CaloSil IP25, one of the most currently used commercial product in the practice. The elimination of the whitish deposits has been investigated with different methods: (1) wiping off the superficial excess of product immediately after each application during the treatment; (2) mechanical cleaning (scalpel) after consolidation; chemical cleaning with rigid gels of water (3), ethylenediaminetetraacetic acid (EDTA) (4) and citric acid (5) after consolidation. The effectiveness of each cleaning method has been assessed by non-destructive methods before and after the consolidation, and repeated after cleaning, by measuring differences in colour, water absorption by capillarity (i.e., sponge test), superficial adhesion (i.e., Scotch Tape Test) and by quantifying the thickness of the deposits eliminated by means of photogrammetry. Results show that both the mechanical cleaning and the removal of the excess of product after each application during the treatment yielded the most promising results for conservation practice.

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