Adhesives for leather and footwear materials. Determination of colour change of white or bright coloured leather surfaces by migration

2011 ◽  
Keyword(s):  
Colour Change

scholarly journals Influence of a Natural Plant Antioxidant on the Ageing Process of Ethylene-norbornene Copolymer (Topas)

2021 ◽  
Vol 22 (8) ◽  
pp. 4018
Author(s):  
Anna Masek ◽  
Angelika Plota
Keyword(s):  
Mechanical Properties ◽  
Food Packaging ◽  
Colour Change ◽  
Good Alternative ◽  
Plant Origin ◽  
Aging Behavior ◽  
Current State ◽  
Ft Ir ◽  
Potential Use

In the field of polymer technology, a variety of mainly synthetic additives are used to stabilize the materials during processing. However, natural compounds of plant origin can be a green alternative to chemicals such as synthetic polyphenols. An analysis of the effect of hesperidin on the aging behavior of ethylene-norbornene copolymer was performed. The evaluation of changes in the tested samples was possible by applying the following tests: determination of the surface energy and OIT values, mechanical properties analysis, colour change measurements, FT-IR and TGA analyses. The obtained results proved that hesperidin can be effectively used as natural stabilizer for polymers. Furthermore, as a result of this compound addition to Topas-silica composites, their surface and physico-mechanical properties have been improved and the resistance to aging significantly increased. Additionally, hesperidin can act as a dye or colour indicator and only few scientific reports describe a possibility of using flavonoids to detect changes in products during their service life, e.g., in food packaging. In the available literature, there is no information about the potential use of hesperidin as a stabilizer for cycloolefin copolymers. Therefore, this approach may contribute not only to the current state of knowledge, but also presents an eco-friendly solution that can be a good alternative to synthetic stabilizers.

scholarly journals Determination of pulp necrosis based on periapical digital radiography histogram and pulp histopathology

2017 ◽  
Vol 29 (3) ◽  
Author(s):  
Emi Khoironi ◽  
Ria Noerianingsih Firman ◽  
Azhari A ◽  
Fahmi Oscandar
Keyword(s):  
Tooth Extraction ◽  
Colour Change ◽  
Descriptive Study ◽  
Visual Observation ◽  
Radiographic Examination ◽  
Apical Region ◽  
Pulp Chamber ◽  
Grey Scale ◽  
Teeth Extraction

Introduction: Radiographic examination is needed to determine the diagnosis of pulp necrosis in addition to a clinical examination. Visual observation was limited in seeing the colour change degree and hence an effort taken by assessing the histogram value. The purpose of this study was to obtain the pulp chamber histogram pattern which reveals its grey scale value, trend, intensity average, histogram variation, and histograms maximum regional of interest (ROI) through digital periapical radiograph. Methods: This study was a descriptive study of the total of nine pulp chamber periapical radiograph data samples. The samples were divided into three groups, the 1st group was the data taken prior to the tooth extraction, the 2nd group was the data collected after the teeth extraction, and the 3rd group was the data of priorly pulpless teeth. Results: There was a tendency of histogram graphic shifting to the left side, likely towards the radiolucent area on ROI of the pulp at the apical region, whilst histopathologically, a massive infiltration of a round PMN cells was found in the area. This finding supported the determination of pulp necrosis diagnose. Conclusion: The tooth with a pulp necrosis showed a tendency that led to radiolucency on periapical radiograph histogram, and histopathologic examination showed massive infiltration of a round PMN cells, thus supported the pulp necrosis diagnose.

scholarly journals Two novel colorimetric probes (5-HMBA-FH and 3-HMBA-FH) based on fluorescein for copper(II) ion detection

2018 ◽  
Vol 96 (12) ◽  
pp. 1037-1045 ◽  
Author(s):  
Guanhong Liu ◽  
Peipei Ren ◽  
Fan Yang ◽  
Xuekai Dou ◽  
Jun Wang ◽  
...  
Keyword(s):  
Infrared Spectrum ◽  
Simultaneous Determination ◽  
Copper Ions ◽  
Colour Change ◽  
High Sensitivity ◽  
Medical Applications ◽  
H Nmr ◽  
Determination Of Copper ◽  
C Nmr

Two novel isomeric colorimetric probes are established for simultaneous determination of copper ions using 2-hydroxy-5-methoxybenzaldehyde fluorescein hydrazone (5-HMBA-FH) and 2-hydroxy-3-methoxybenzaldehyde fluorescein hydrazone (3-HMBA-FH). They are synthesized by reacting fluorescein hydrazide with 2-hydroxy-5-methoxybenzaldehyde and 2-hydroxy-3-methoxybenzaldehyde, respectively, and then characterized by 1H-NMR, 13C-NMR, and infrared spectrum. The addition of copper ions to the solutions of two novel colorimetric probes can generate the obviously peaks at 498 nm in UV–vis absorption spectra along with a rapid colour change from colourless to dark yellow. The detection limits of the method for Cu2+ ion were 3.442 × 10−6 mol/L and 3.682 × 10−6 mol/L separately for 5-HMBA-FH and 3-HMBA-FH, respectively. The additions of other metal ions hardly affect the determination of copper ions. The proposed method was successfully applied to the analysis of Cu2+ ions in various samples. This method possesses high sensitivity, high simplicity, and minimized interference and will provide a great advantage in detecting copper ions in the environment, food, and medical applications.

scholarly journals Determination of Lignin Modifying Enzymes from Pleurotus ostreatus and Lentinus squarrosulus

2021 ◽  
pp. 39-45
Author(s):  
S. B. Chuku ◽  
E. O. Nwachukwu ◽  
I. O. Agbagwa ◽  
H. O. Stanley
Keyword(s):  
Pleurotus Ostreatus ◽  
Large Scale ◽  
Extracellular Enzymes ◽  
Colour Change ◽  
White Rot Fungi ◽  
White Rot ◽  
Scale Production ◽  
Large Scale Production ◽  
Physiological Group

Fungi play vital roles as decomposers. White rot fungi are an eco-physiological group that degrades wood by the secretion of specialized extracellular enzymes including lignin-modifying enzymes. There is growing interest in the use of extracellular enzymes for bioremediation. This study determined the Lignin Modifying Enzymes (LMEs) associated with two species of mushroom, Pleurotus ostreatus and Lentinus squarrosulus. The qualitative study was conducted using agar medium substituted with chromogenic substances to determine the production of LMEs by the species. The appearance of colour change and clearance due to reaction with chromogenic substrates were used to determine LMEs production by the fungi. The results showed that Pleurotus ostreatus and Lentinus squarrosulus tested positive by the appearance of light brown colouration, reddish-brown colouration and discolouration of media for overall polyphenol oxidase, Laccase and Peroxidase activity, respectively. The study showed that the species studied are candidates for large scale production of LMEs that can be utilized as an eco-friendly solution for bioremediation of contaminated sites.

scholarly journals DETERMINATION OF THE EFFECT OF SOCIALLY ACCEPTABLE BEVERAGES ON THE COLOUR STABILITY OF COMPOSITE RESTORATIONS

2019 ◽  
Vol 8 (5) ◽  
Author(s):  
Vandana James ◽  
Sundaresan Balagopal ◽  
Manishaa. V ◽  
Sunil Chandy Varghese ◽  
Vaishnavi. I ◽  
...  
Keyword(s):  
Red Wine ◽  
Resin Composite ◽  
Colour Change ◽  
Alcoholic Beverages ◽  
Control Group ◽  
Distilled Water ◽  
Colour Stability ◽  
Composite Restorations ◽  
Time Period

Introduction: Esthetic failure is the commonest reason for replacement of restorations. Consumption of certain beverages may affect the esthetic and physical properties of the resin composite, thereby undermining the quality of restorations. Aim: To determine and evaluate the colour stability of composite restorations when immersed in socially acceptable and commonly consumed alcoholic beverages for 14 days. Materials and method: 50 composite disks were prepared with the help of a mould made of rubber base impression material and later finished and polished. The samples were divided into 5 groups (n=10) and immersed in distilled water (as control), red wine, beer, brandy and whisky for fifteen minutes every day for fourteen days. The colour change of the samples was measured using a spectrophotometer on the first (24hrs) and fourteenth day. Results: Comparing all the beverages, red wine showed the maximum colour change with a ΔE* value of 12.08. The least colour change among the beverages was seen in whisky that had a ΔE* value = 5.45. Even the control group in distilled water showed a ΔE* value of 0.89. Conclusion: At the end of this study, it was evident that alcoholic beverages do produce discolouration. The rate of this discolouration depends upon the characteristics of the beverage and the composite material as well as the time period of immersion. Hence it is imperative to educate the patients regarding the effects of alcoholic beverages on their restorations too.  Keywords:  Composite, esthetics, alcoholic beverages, discolouration

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