Monitoring of Wool Stretching Process Using Polarized Second Harmonic Generation

This revised book is an expanded and updated version of the Australian Sheep and Wool Handbook published in 1991 and focuses on the sheep wool and meat industry. The book is divided in 5 sections, each including several chapters written by well-known and qualified researchers and industry representatives from many countries. The first section on Major sheep and wool industries, in my opinion, is particularly interesting because it explores the sheep and wool industries of leading countries (e.g. Australia, South Africa and New Zealand) and continents (Europe and South America), and those of emerging countries (e.g. China).....

Two-photon polymerization (TPP) based on laser direct writing is currently one of the most prevailing 3D micro/nano fabrication techniques. Nanomaterials can be doped in resins and assembled by TPP for developing advanced 3D functional devices. However, there lacks an effective visualization tool to determine the distribution and orientation of the nanomaterials as-doped in the composite resins. Herein, we present a nondestructive, in situ, and rapid characterization method to determine the orientation and distribution of the nanomaterials within cured resins using polarized second-harmonic generation (p-SHG). The directional assembly of the ZnO nanowires within micro/nanostructures fabricated by TPP is, for the first time to the best of our knowledge, characterized by p-SHG optical microscopy with a fast imaging speed by two orders of magnitude higher than that of the Raman mapping technique. Our method opens a window for nondestructive, rapid, in situ, and polarization-resolved characterization of functional devices made by TPP micro/nanofabrication.

We determined inhomogeneity of strains around discontinuities as well as changes in orientation of collagen fibrils under applied load in skin. Second Harmonic Generation (SHG) images of collagen fibrils were obtained at different strain magnitudes. Changes in collagen orientation were analyzed using Fast Fourier Transforms (FFT) while strain inhomogeneity was determined at different distances from hair follicles using Digital Image Correlation (DIC). A parameter, defined as the Collagen Orientation Index (COI), is introduced that accounts for the increasingly ellipsoidal nature of the FFT amplitude images upon loading. We show that the COI demonstrates two distinct mechanical regimes, one at low strains (0%, 2.5%, 5% strain) in which randomly oriented collagen fibrils align in the direction of applied deformation. In the second regime, beginning at 5% strain, collagen fibrils elongate in response to applied deformation. Furthermore, the COI is also found to be linearly correlated with the applied stress indicating that collagen fibrils orient to take the applied load. DIC results indicated that major principal strains were found to increase with increased load at all locations. In contrast, minimum principal strain was dependent on distance from hair follicles. These findings are significant because global and local changes in collagen deformations are expected to be changed by disease, and could affect stem cell populations surrounding hair follicles, including mesenchymal stem cells within the outer root sheath.

PURPOSE: Significant remodeling of the extracellular matrix (ECM) occurs in human ovarian cancer and has been observed in both high grade and low grade tumors as well as ovaries from high risk patients with BRCA mutations. Uniquely quantifying alterations in the tumor microenvironment (TME) could be used as a new diagnostic tool, e.g. to complement histology; provide insight into disease etiology; and assess treatment efficacy through minimally invasive in vivo imaging. Current clinical modalities (CT, MRI, PET) lack the resolution for this purpose. Our efforts have focused on examining collagen alterations across a spectrum of human ovarian tumors, where the changes can serve as quantitative biomarkers. Alterations can be reflected in increased collagen concentration, changes in alignment of collagen molecules within fibrils and/or fibers and/or up-regulation of different collagen isoforms, e.g. Col III. METHODS AND RESULTS: We used the collagen specific/sensitive Second Harmonic Generation (SHG) imaging microscopy to probe collagen architecture over size scales that range from the macromolecular structural properties to fibril/fiber morphology. First, we used SHG polarization analyses to probe collagen macromolecular/supramolecular properties to discriminate ex vivo human tissues (normal stroma, benign tumors, and high grade serous tumors) by determination of: i) collagen alpha helical pitch angle, ii) alignment of collagen molecules within fibrils, and iii) collagen helical chirality via SHG circular dichroism (SHG-CD). The largest differences were between normal stroma and benign tumors, consistent with gene expression data showing Col III is up-regulated in the latter. The different tissues also displayed differing collagen alignment within fibrils and SHG-CD responses, consistent with either Col III incorporation or randomization of Col I alignment within benign and high-grade tumors fibrils. These results collectively indicate the fibril assemblies are distinct in all tissues and likely result from synthesis of new collagen rather than remodeling of existing collagen. Importantly, these techniques do not require exogenous labels, and additionally, provide sub-resolution structural information previously obtained through ultrastructural analysis that cannot be performed on intact tissues. We next implemented a novel form of 3D texture analysis and machine learning to delineate the fibrillar morphology observed in SHG images of normal stroma, high risk stroma, benign tumors, and a spectrum of malignant tumors (high grade serous, low grade serous, and endometrioid). We extracted textural features in the 3D image sets to build statistical models of each class and we achieved clinically significant 83-91% classification accuracies for the six classes. Importantly, the 3D analysis significantly outperformed our prior 2D methods. This classification based on collagen morphology will complement conventional classification based on genetic profiles and can serve as an additional biomarker. CONCLUSIONS: Taken together, the combination of the macro/supramolecular probes and the fiber morphology classification will greatly increase our understanding of the TME evolution in human ovarian cancer. These methods and their findings have clinical translational significance in terms of understanding disease etiology, and also by enhancing prognostic and diagnostic capabilities. Citation Format: Kirby R. Campbell, Rajeev Chaudhary, Julia Handel, Bruce Wen, Vikas Singh, Manish Patankar and Paul J. Campagnola. COLLAGEN ALTERATIONS IN HUMAN OVARIAN CANCER PROBED BY SECOND HARMONIC GENERATION (SHG) IMAGING MICROSCOPY [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr AP19.

Influence of Neem oil pretreatment on the dyeing and antimicrobial properties of wool and silk fibers with some natural dyes

Collagen is critical to the structure and function of skin tissues, with the collagen I/III ratios influencing fibrillogenesis, fiber organization, and skin mechanics. Abnormal collagen organization, such as in fibrosis or scar tissue, compromises both skin functionality and aesthetics. In this study, we employed label-free polarization resolved second harmonic generation (PSHG) microscopy to investigate collagen structure in artificial collagen matrices with various Col I/III ratios at the fibril scale (∼1 to 3μm) and in ex vivo human healthy and scarred skin at the fiber scale (∼10 to 20μm). Complementary third harmonic generation (THG) microscopy provided additional structural information. Our results indicate that an increasing Col I/III ratio is associated with longer fibril length, higher PSHG intensity, and a reduced effective α-helix pitch angle of fibrils. In pure Col I, the effective α-helix pitch angle is determined to be 47.72∘. These observations indicate alterations in fibril assembly. Furthermore, although the α-helix pitch angle of fibers in both healthy and scarred skin was approximately 46.7∘, healthy skin exhibited 24% greater variability in fiber orientation, suggesting a more randomized organization compared to scar tissue. THG imaging further revealed a higher cellular density in scar tissue, consistent with the inflammatory activity associated with wound healing. Immunohistochemical (IHC) staining using dermatansulphate and Col III-specific antibodies confirmed that the Col I/III ratio is higher in healthy skin (2.2) than in scarred skin (1.6). These findings underscore the potential of PSHG microscopy for label-free, quantitative assessment of collagen structure across multiple scales, with THG offering complementary cellular insights. This integrated approach represents a promising strategy for real-time, in vivo monitoring and automated quantification of collagen organization in clinical applications, including dermatology, burn treatment, and fibrosis monitoring.

The poly(lactic acid) (PLA)/ramie fiber biocomposites were fabricated, which exhibited considerable reinforcement effect comparable to the glass fiber at the same loading. The attempts were made to understand the flow-induced morphology of ramie fibers and PLA crystals in the injection-molded PLA/ramie fiber biocomposites, thus revealing its relationship to biocomposite mechanical properties. The polarized optical microscopy (POM) and two-dimensional wide-angle X-ray diffraction (2D-WAXD) were for the first time used to determine the distribution of nature fibers, which interestingly showed the ramie fibers aligned well along the flow direction over the whole thickness of injection-molded parts, instead of skin-core structure. This easy alignment of ramie fibers during the common processing was ascribed to the intrinsically high flexibility of ramie fibers and strong interfacial interaction between PLA chains and cellulose molecules of ramie fibers. Both 2D-WAXD and differential scanning calorimeter (DSC) measurements suggested that the PLA matrix in its ramie biocomposites had rather high orientation degree and crystallinity, which was attributed to effective heterogeneous nucleation induced by ramie fibers and local shearing field in the vicinity of fiber surface. Remarkable improvement of mechanical and thermo-mechanical properties was achieved for PLA/ramie fiber biocomposites, without sacrifice of toughness and ductility. Addition of 30wt% ramie fibers increased the tensile strength and modulus of PLA/ramie fiber biocomposites from 65.6 and 1468 MPa for pure PLA to 91.3 and 2977 MPa, respectively. These superior mechanical properties were ascribed to easy alignment of ramie fibers, high crystallinity of PLA, and favorable interfacial adhesion as revealed by scanning electron microscopy (SEM) observation and theoretical analysis based on dynamic mechanical analysis (DMA) data.

Knowledge about the size and distribution of returns from alternative broad types of R&D and promotion investments permit strategic-level decisions about resource allocation, both within and across research programs. The Australian sheep meat and wool industries are characterised by strong cross-commodity relationships due to the joint product nature of the industries. An equilibrium displacement model of the Australian sheep meat and wool industries was developed to account for these relationships and any indirect benefits and costs arising from spill-over and feedback effects between the industries as a result of research-induced innovation or promotion. The potential annual returns and their distribution among the various industry sectors were estimated from different hypothetical investment scenarios to demonstrate the model's relevance to R&D and promotion policy and decision-making.

In recent years, people have begun to apply computer technology to various fields, which has led to the rapid development of computer image analysis. Computer image analysis can fully reflect the structural characteristics of the surface of an object, and can perform objective judgments and recognition, which is a relatively ideal detection method. It is very important to analyze and study the commonalities and characteristics of objects reasonably and accurately, and extract effective indicators to improve the ability of discrimination. The purpose of this article is to study the application of computer technology in image recognition. This paper proposes a detection method based on gray scale transformation and supplemented by frequency domain transformation. Comprehensive use of image segmentation, edge extraction, and image restoration technology. This paper analyzes and compares the surface morphology of cashmere and wool fibers, and finds indicators that can effectively distinguish the two, such as fiber diameter, diameter-to-height ratio, visible height of scales, etc., and compares the obtained fiber images under the scanning electron microscope. Carry out a series of processing in order to obtain the above-mentioned characteristic parameters, so as to carry out analysis and research, establish a characteristic database, use the statistical model of BP neural network, carry out sample training, achieve the purpose of effective identification, and finally establish a set of automatic wool and cashmere fibers. The analysis and recognition system provides a strong theoretical basis. Experimental research shows that this paper can calculate from the measurement data that the average diameters of cashmere fiber and wool fiber are 14.5ìm and 18.46ìm, respectively, and the average scale heights are 16.27ìm and 11.52ìm, which can prove that the measured data are within tolerance. Therefore, it can be explained that the index extraction method used in this article is effective.

Mineralization and collagen orientation throughout aging at the vertebral endplate in the human lumbar spine

Second harmonic generation (SHG) microscopy is widely used to image collagen fiber microarchitecture due to its high spatial resolution, optical sectioning capabilities and relatively nondestructive sample preparation. Quantification of SHG images requires sensitive methods to capture fiber alignment. This article presents a two-dimensional discrete Fourier transform (DFT)-based method for collagen fiber structure analysis from SHG images. The method includes integrated periodicity plus smooth image decomposition for correction of DFT edge discontinuity artefact, avoiding the loss of peripheral image data encountered with more commonly used windowing methods. Outputted parameters are as follows: the collagen fiber orientation distribution, aligned collagen content and the degree of collagen fiber dispersion along the principal orientation. We demonstrate its application to determine collagen microstructure in the human optic nerve head, showing its capability to accurately capture characteristic structural features including radial fiber alignment in the innermost layers of the bounding sclera and a circumferential collagen ring in the mid-stromal tissue. Higher spatial resolution rendering of individual lamina cribrosa beams within the nerve head is also demonstrated. Validation of the method is provided in the form of correlative results from wide-angle X-ray scattering and application of the presented method to other fibrous tissues.

Advanced quantitative imaging and biomechanical analyses of periosteal fibers in accelerated bone growth

Collagen fiber architecture within the skeletal muscle extracellular matrix (ECM) is significant to passive muscle mechanics. While it is thought that collagen fibers re-orient themselves in response to changes in muscle length, this has not been dynamically visualized and quantified within a muscle. The goal of this study was to measure changes in collagen alignment across a range of muscle lengths and compare the corresponding alignment to muscle mechanics. We hypothesized that collagen fibers dynamically increase alignment in response to muscle stretching, and this change in alignment is related to passive muscle stiffness. Further, we hypothesized that digesting collagen fibers with collagenase would reduce the re-alignment response to muscle stretching. Using DBA/2J and D2.mdx mice, we isolated extensor digitorum longus (EDL), soleus, and diaphragm muscles for collagenase or sham treatment and decellularization to isolate intact or collagenase-digested decellularized muscles (DCMs). These DCMs were mechanically tested and imaged using second harmonic generation microscopy to measure collagen alignment across a range of strains. We found that collagen alignment increased in a strain-dependent fashion, but collagenase did not significantly affect the strain-dependent change in alignment. We also saw that the collagen fibers in the diaphragm epimysium (surface ECM) and perimysium (deep ECM) started at different angles, but still re-oriented in the same direction in response to stretching. These robust changes in collagen alignment were weakly related to passive DCM stiffness. Overall, we demonstrated that the architecture of muscle ECM is dynamic in response to strain and is related to passive muscle mechanics. Statement of significanceOur study presents a unique visualization and quantification of strain-induced changes in muscle collagen fiber alignment as they relate to passive mechanics. Using dynamic imaging of collagen in skeletal muscle we demonstrate that as skeletal muscle is stretched, collagen fibers re-orient themselves along the axis of stretch and increase their alignment. The degree of alignment and the increase in alignment are each weakly related to passive muscle stiffness. Collagenase treatments further demonstrate that the basis for muscle Extracellular matrix stiffness is dependent on factors beyond collagen crosslinking and alignment. Together the study contributes to the knowledge of the structure-function relationships of muscle extracellular matrix to tissue stiffness relevant to conditions of fibrosis and aberrant stiffness.

We have used second harmonic generation (SHG) imaging to quantify a strong intrinsic SHG-signal from cellular and subcellular muscle fibre preparations. In isolated single muscle cells,the intrinsic SHG-signal periodically follows the striation pattern and strongly depends on the sarcomere length and the polarization of the illuminating laser beam. At the subcellular level,the SHG signal seems to be located mainly at the overlapping region of the (thin) actin and (thick) myosin filaments. Thus,SHG imaging resolves the arrangement of the contractile structures with high resolution non-invasively and without chromophores. It may also allow to study dynamic molecular interactions of the motor protein myosin with actin filaments during force production and muscle shortening.

A deep learning approach to estimate chemically-treated collagenous tissue nonlinear anisotropic stress-strain responses from microscopy images.