Changes to the Collagen Structure using Vibrational Spectroscopy and Chemometrics: A Comparison between Chemical and Sulfide-Free Leather Process

2021 ◽  
Vol 116 (11) ◽  
Author(s):  
Megha Mehta ◽  
Yang Liu ◽  
Rafea Naffa ◽  
Mark Waterland ◽  
Geoff Holmes
Keyword(s):  
Principal Component Analysis ◽  
Environmental Impact ◽  
Proteolytic Enzyme ◽  
Structural Changes ◽  
Principal Component ◽  
Collagen Structure ◽  
Enzymatic Method ◽  
Leather Processing ◽  
Biochemical Approach ◽  
Physical Changes

Chemical and physical changes take place when hides and skins are processed to leather that affect the quality and strength of the material. Understanding the structure at each leather-making stage is the basis of this study but also intend to improve the process through a biochemical approach, employing a proteolytic enzyme for processing leather more cleanly with reduced environmental impact. Raman and ATR-FTIR spectroscopy in conjunction with chemometrics was used to investigate each leather-making stage from fresh green cattle hide to dry crust leather. The changes in proteins, lipids, nucleic acids and other biomolecules with leather processing was measured and reported using three novel Raman ratiometric markers, 920/1476, 1345/1259 and 1605/1476 cm-1, to discriminate the structural changes in collagen of hide using standard chemical and enzymatic method. Amide I band was deconvoluted to investigate thecollagen secondary structures using curve fitting by Gaussians function. The results of Principal Component Analysis are well-corroborated with the ratiometric markers of structural changes.

Reflectance FTIR Microspectroscopy for Studying Effect of Xylan Removal on Unbleached and Bleached Birch Kraft Pulps

Holzforschung ◽  
2002 ◽  
Vol 56 (5) ◽  
pp. 513-521 ◽  
Author(s):  
M. Ristolainen ◽  
R. Alén ◽  
P. Malkavaara ◽  
J. Pere
Keyword(s):  
Principal Component Analysis ◽  
Fiber Surface ◽  
Principal Component ◽  
Component Analysis ◽  
Pulp Fiber ◽  
Kraft Pulps ◽  
Partial Removal ◽  
Ftir Microspectroscopy ◽  
Reflectance Ftir ◽  
Physical Changes

Summary The effect of the partial removal of xylan on unbleached and bleached birch kraft pulps was investigated by Fourier transform infrared (FTIR) microspectroscopy and the resulting data were analyzed by multivariate data analysis, i.e., principal component analysis (PCA) and maximum likelihood principal component analysis (MLPCA). Isolated model substances (xylan, cellulose and lignin) were used to calibrate these methods. Clear chemical changes in the relative proportions of the main constituents and functional groups on the pulp fiber surface were observed as a function of the amount of xylan removed. In addition, due to the partial removal of xylan, indications of some physical changes were observed.

scholarly journals Principal Component Analysis of the Potential for Increased Rail Competitiveness in East-Central Europe

2019 ◽  
Vol 11 (15) ◽  
pp. 4181 ◽  
Author(s):  
Szabolcs Duleba ◽  
Bálint Farkas
Keyword(s):  
Principal Component Analysis ◽  
Latent Variable ◽  
Structural Changes ◽  
Principal Component ◽  
Component Analysis ◽  
Factor Space ◽  
Market Liberalization ◽  
East Central Europe ◽  
East Central ◽  
Rail Freight

Increased rail competitiveness has been the objective of many countries around the world, including member states of the EU. Although railway market liberalization has always been accompanied by high expectations of increased efficiency and competitiveness, the overall impact of such decisions can be considered controversial. This paper aims to contribute to the scientific debate by conducting a factor analysis of some East-Central European countries from the aspect of rail freight competitiveness. Since many highly correlated factors influence competitiveness, its mathematical–statistical representation and analysis is difficult due to the high number of dimensions of the factor space. Moreover, competitiveness cannot be measured directly only as a latent variable which is a feature of Principal Component Analysis (PCA). The introduced PCA, model by way of reducing the number of dimensions, can highlight the relations among the attributes and determine the most crucial issues capable of increasing rail competitiveness in the given countries and also of clustering those national railway markets. Recommendations for structural changes in national rail freight markets of the region are also supplied. Our results show that international rail competitiveness depends rather on market efficiency than on market liberalization due to the fact that the Global Competitiveness Index and Export/Import attributes did not significantly correlate with market concentration. As for the larger domestic rail freight sectors, small freight forwarders—spawned by liberalization—are shown to play a significant role in increasing competitiveness.

Structural performance assessment considering both observed and latent environmental and operational conditions: A Gaussian process and probability principal component analysis method

2022 ◽  
pp. 147592172110620
Author(s):  
Yi-Chen Zhu ◽  
Wen Xiong ◽  
Xiao-Dong Song
Keyword(s):  
Principal Component Analysis ◽  
Gaussian Process ◽  
Performance Assessment ◽  
Structural Changes ◽  
Principal Component ◽  
Component Analysis ◽  
Assessment Model ◽  
Monitoring Data ◽  
Model Parameters ◽  
Structural Responses

Structural faults like damage and degradations will cause changes in structure response data. Performance assessment can be conducted by investigating such changes. In real implementations however, structural responses are affected by environmental and operational variations (EOVs) as well. Such variation should be well captured by the assessment model when detecting structural changes. It should be noted that not all EOVs can be measured by the monitoring system. When both observed and latent EOVs have significant effects on the monitored structural responses, these two effects should be considered properly. Furthermore, uncertainties can be significant for the monitoring data since loads and EOVs cannot be directly controlled under working conditions. To address these problems, this work proposes a performance assessment method considering both observed and latent EOVs. A Gaussian process is used to model the functional behaviour between structural response and observed EOVs whilst principal component analysis is used to eliminate the effect of latent EOVs. These two methods are combined using a Bayesian formulation and the effect of both observed and latent EOVs are modelled. The associated model parameters are inferred through probability density functions to account for the uncertainties. A synthetic data example is presented to validate the proposed method. It is also applied to the monitoring data of a long-span cable-stayed bridge with different damage scenarios considered, illustrating its capability of real implementations in structural health monitoring.

Studies on Collagen Structure using X-Ray Scattering on a Closed-Loop Leather Process

2020 ◽  
Vol 115 (10) ◽  
pp. 373-379
Author(s):  
Yi Zhang ◽  
Jenna Buchanan ◽  
Jiasheng Su ◽  
Zhuangdou Zhang ◽  
Geoff Holmes ◽  
...  
Keyword(s):  
Structural Changes ◽  
Closed Loop ◽  
Collagen Matrix ◽  
Collagen Structure ◽  
Leather Industry ◽  
Scattering Intensity ◽  
X Ray ◽  
Leather Processing ◽  
X Ray Scattering ◽  
Ray Scattering

Waste management in leather processing is crucial in limiting the excess use of hazardous materials that lead to environmental pollution and health concerns. A closed-loop approach was developed to recycle the spent solutions from leather processing to reduce waste in the effluent. The structural changes of collagen that accompany such processing are yet to be studied and is crucial in understanding the closed-loop process and its subsequent leather properties. In this study, we analysed the collagen structure at different processing stages across the closed-loop approach using synchrotron small-angle X-ray scattering. An increased filling effect in the collagen matrix was observed and attributed to the residual organic component and chromium species in recycled spent solutions. A high uptake of chromium was also observed from the increased scattering intensity from leathers treated with recycled chrome solution, indicating its efficient use. Additionally, the changes in scattering intensity from keratin and lipids indicated an effective unhairing process. Such findings on collagen structure changes will support the development of more environmentally and economically sustainable processing methods to benefit the leather industry.

scholarly journals Evaluation of the Potential Use of Levan Polysaccharide in Paper Conservation

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Rumeysa Ozen Saglam ◽  
Seval Genc ◽  
Ebru Toksoy Oner
Keyword(s):  
Principal Component Analysis ◽  
Principal Component ◽  
Gap Filling ◽  
Specific Kind ◽  
Factors Affecting ◽  
Color Shift ◽  
Physical Changes ◽  
First Time ◽  
Potential Use ◽  
Accelerated Thermal Aging

Conservation of paper-based materials, namely, manuscripts, includes repair of tears, gap filling, consolidation, and fixation, which requires the use of adhesives. The adhesive in use for these purposes should be compatible with the chemical and physical properties of paper and should present good aging characteristics. In this study, we conducted a set of experiments with paper samples on which fructan-based biopolymer Halomonas levan (Hlevan) was applied for the first time and compared with glucan-based adhesive starch. Adhesive-applied samples were initially prepared by the application of different historical recipes of sizing and ink. Then, they underwent accelerated thermal aging. Chemical and physical changes of paper samples (crystallinity, pH, and color) were analyzed. Finally, Principal Component Analysis was performed to identify dominating factors affecting sample behavior with applied adhesives. This study demonstrates the aging characteristics of Hlevan on cellulose-based materials. The results showed that there is a color shift from blue to yellow for all samples after aging, but it is more pronounced for some samples with Hlevan. In addition, Hlevan is slightly less acidic than starch in all cases and acted as a plasticizer for a specific kind of sizing material. The methodology of this research is also efficacious in terms of understanding the interaction of paper media with the adhesives and their effects on aging.

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