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1. Modified Fibrous Mass of Leather and Paper Waste for the Production of Packaging Paper and Cardboard

Author

Adham Rafikov, Nargis Kadirova, and Gulnoza Jurayeva

Subjects
leather, paper, waste, packaging paper, cardboard, alkaline modification, collagen, Textile bleaching, dyeing, printing, etc., TP890-933, Large industry. Factory system. Big business, HD2350.8-2356
Abstract

Recycling leather waste, which accumulates in large quantities in tanneries, and producing packaging paper with improved properties reduces the environmental burden and is at the same time economically efficient. A modified fibrous mass of waste from tanned and untanned leather scraps, waste paper, and acrylic emulsion was obtained and packaging paper based on them was produced. Alkaline modification of tanned leather waste - chrome shavings - leads to an increase in the electrokinetic potential and, accordingly, the stability of the fibrous suspension, partial hydrolysis of skin collagen occurs with the formation of new polar groups, and at the same time, the degree of cross-linking of the skin increases. In the paper composition, new intermolecular bonds are formed between cellulose and skin collagen. The microstructure, elemental composition, morphology, thermal and physical-mechanical properties of modified chrome shavings and composite paper were determined. A significant improvement has been achieved in the main parameters of paper: surface density (decrease by 16-25%), breaking load and breaking length (increase by 15-23%), number of double bends (increase by 2-6 times) in comparison with paper obtained from pure waste paper, and also to a greater extent compared to paper obtained from unmodified leather waste.

Published
2024
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2. Journal of Biomedical Optics

Author

Adriana C, Salazar Coariti, Maurice S, Fabien, Johnny, Guzman, Jeffrey A, McGuire, Raffaella, De Vita, and Kimani C, Toussaint

Subjects
Paper, collagen, Biomaterials, Microscopy, fluid mechanics, Biomedical Engineering, vector fields, waviness, Atomic and Molecular Physics, and Optics, Extracellular Matrix, Skin, second-harmonic generation, Electronic, Optical and Magnetic Materials
Abstract

Significance: The spatial organization of collagen fibers has been used as a biomarker for assessing injury and disease progression. However, quantifying this organization for complex structures is challenging. Aim: To quantify and classify complex collagen fiber organizations. Approach: Using quantitative second-harmonic generation (SHG) microscopy, we show that collagen-fiber orientation can be viewed as pseudovector fields. Subsequently, we analyze them using fluid mechanic metrics, such as energy U, enstrophy E, and tortuosity tau. Results: We show that metrics used in fluid mechanics for analyzing fluid flow can be adapted to analyze complex collagen fiber organization. As examples, we consider SHG images of collagenous tissue for straight, wavy, and circular fiber structures. Conclusions: The results of this study show the utility of the chosen metrics to distinguish diverse and complex collagen organizations. We find that the distribution of values for E and U increases with collagen fiber disorganization, where they divide between low and high values corresponding to uniformly aligned fibers and disorganized collagen fibers, respectively. We also confirm that the values of tau cluster around 1 when the fibers are straight, and the range increases up to 1.5 when wavier fibers are present. (C) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 International License. Published version

Published
2022

3. Quantifying optical anisotropy in soft tissue membranes using Mueller matrix imaging

Author

Alexander W. Dixon, Martyn P. Nash, Andrew J. Taberner, and Poul M. F. Nielsen

Subjects
Diagnostic Imaging, Paper, collagen, bioprosthetic heart valves, Materials science, optical polarization, Mueller matrix imaging, Biomedical Engineering, Imaging, Biomaterials, Animals, Mueller calculus, Anisotropy, Birefringence, Optical Imaging, Soft tissue, Optical polarization, Polarimeter, Polarization (waves), Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Membrane, tissue anisotropy, Cattle, Biomedical engineering
Abstract

Significance: A non-destructive technique for accurately characterizing the spatial distribution of optical properties of soft tissue membranes may give improved outcomes in many tissue engineering applications. Aim: This study aimed to develop a non-destructive macroscopic imaging technique that is sensitive to optical anisotropy, typical of fibrous components in soft tissue membranes, and can address some of the difficulties caused by the complex turbid nature of these tissues. Approach: A near-infrared Mueller matrix imaging polarimeter employing logarithm decomposition was developed and used to conduct transmission measurements of all the polarization properties across the full thickness of bovine pericardium tissue. Results: The full Mueller matrix was measured across a 70 mm×70 mm sample of calf bovine pericardium and revealed significant retardance (linear and circular) and depolarization in this tissue. Regions with a uniform axis of optical anisotropy were identified. Mueller matrix imaging demonstrated that the exhibited circular retardance was sufficient to lead to possible misinterpretation of apparent fiber orientation when using conventional polarization imaging techniques for such tissues. Conclusions: Mueller matrix imaging can identify regional distributions of optical anisotropy in calf bovine pericardium. This new capability is a promising development in non-destructive imaging for tissue selection.

Published
2021