Sample records for cartilage surface structure

  1. Cartilage. (United States)

    Caplan, Arnold I.


    Cartilage is a fundamental biological material that helps to shape the body and then helps to support it. Its fundamental properties of strength and resilience are explained in terms of the tissue's molecular structure. (JN)

  2. Aggrecan structure in amphibian cartilage

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    Covizi D.Z.


    Full Text Available The structure of the large proteoglycan present in the bullfrog epiphyseal cartilage was studied by immunochemical and biochemical methods. The isolated monomer showed a polydisperse behavior on Sepharose CL2B, with a peak at Kav = 0.14. Chondroitin sulfate chains were identified by HPLC analysis of the products formed by chondroitinase digestion and mercuric acetate treatment. These chains have approximately 38 disaccharides, a Di45:Di68 ratio of 1.6 and GalNAc4S + GalNAc4,6S are the main non-reducing terminals. Keratan sulfate was identified by the use of two monoclonal antibodies in Western blots after chondroitinase ABC treatment. A keratan sulfate-rich region (~110 kDa was isolated by sequential treatment with chondroitinase ABC and proteases. We also employed antibodies in Western blotting experiments and showed that the full length deglycosylated core protein is about 300 kDa after SDS-PAGE. Domain-specific antibodies revealed the presence of immunoreactive sites corresponding to G1/G2 and G3 globular domains and the characterization of this large proteoglycan as aggrecan. The results indicate the high conservation of the aggrecan domain structure in this lower vertebrate.

  3. Association of 3-Dimensional Cartilage and Bone Structure with Articular Cartilage Properties in and Adjacent to Autologous Osteochondral Grafts after 6 and 12 Months in a Goat Model (United States)

    Chan, Elaine F.; Liu, I-Ling; Semler, Eric J.; Aberman, Harold M.; Simon, Timothy M.; Chen, Albert C.; Truncale, Kate G.


    Objective: The articular cartilage of autologous osteochondral grafts is typically different in structure and function from local host cartilage and thereby presents a remodeling challenge. The hypothesis of this study was that properties of the articular cartilage of trochlear autografts and adjacent femoral condyle are associated with the 3-dimensional (3-D) geometrical match between grafted and contralateral joints at 6 and 12 months after surgery. Design: Autografts were transferred unilaterally from the lateral trochlea (LT) to the medial femoral condyle (MFC) in adult Spanish goats. Operated and contralateral nonoperated joints were harvested at 6 and 12 months and analyzed by indentation testing, micro–computed tomography, and histology to compare 1) histological indices of repair, 2) 3-D structure (articular surface deviation, bone-cartilage interface deviation, cartilage thickness), 3) indentation stiffness, and 4) correlations between stiffness and 3-D structure. Results: Cartilage deterioration was present in grafts at 6 months and more severe at 12 months. Cartilage thickness and normalized stiffness of the operated MFC were lower than the nonoperated MFC within the graft and proximal adjacent host regions. Operated MFC articular surfaces were recessed relative to the nonoperated MFC and exhibited lower cartilage stiffness with increasing recession. Sites with large bone-cartilage interface deviations, both proud and recessed, were associated with recessed articular surfaces and low cartilage stiffness. Conclusion: The effectiveness of cartilage repair by osteochondral grafting is associated with the match of 3-D cartilage and bone geometry to the native osteochondral structure. PMID:24224069

  4. Alteration of cartilage surface collagen fibers differs locally after immobilization of knee joints in rats (United States)

    Nagai, Momoko; Aoyama, Tomoki; Ito, Akira; Tajino, Junichi; Iijima, Hirotaka; Yamaguchi, Shoki; Zhang, Xiangkai; Kuroki, Hiroshi


    The purpose of this study was to examine the ultrastructural changes of surface cartilage collagen fibers, which differ by region and the length of the experimental period in an immobilization model of rat. Male Wistar rats were randomly divided into histological or macroscopic and ultrastructural assessment groups. The left knees of all the animals were surgically immobilized by external fixation for 1, 2, 4, 8 or 16 weeks (n = 5/time point). Sagittal histological sections of the medial mid-condylar region of the knee were obtained and assessed in four specific regions (contact and peripheral regions of the femur and tibia) and two zones (superficial and deep). To semi-quantify the staining intensity of the collagen fibers in the cartilage, picrosirius red staining was used. The cartilage surface changes of all the assessed regions were investigated by scanning electron microscopy (SEM). From histological and SEM observations, the fibrillation and irregular changes of the cartilage surface were more severe in the peripheral region than in the contact region. Interestingly, at 16 weeks post-immobilization, we observed non-fibrous structures at both the contact and peripheral regions. The collagen fiber staining intensity decreased in the contact region compared with the peripheral region. In conclusion, the alteration of surface collagen fiber ultrastructure and collagen staining intensity differed by the specific cartilage regions after immobilization. These results demonstrate that the progressive degeneration of cartilage is region specific, and depends on the length of the immobilization period. PMID:25939458

  5. Automatic quantification of local and global articular cartilage surface curvature

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    Folkesson, Jenny; Dam, Erik B; Olsen, Ole F


    The objective of this study was to quantitatively assess the surface curvature of the articular cartilage from low-field magnetic resonance imaging (MRI) data, and to investigate its role in populations with varying radiographic signs of osteoarthritis (OA), cross-sectionally and longitudinally. ...

  6. Ultrasonic reflection coefficient and surface roughness index of OA articular cartilage: relation to pathological assessment

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    Niu Hai-jun


    Full Text Available Abstract Background Early diagnosis of Osteoarthritis (OA is essential for preventing further cartilage destruction and decreasing severe complications. The aims of this study are to explore the relationship between OA pathological grades and quantitative acoustic parameters and to provide more objective criteria for ultrasonic microscopic evaluation of the OA cartilage. Methods Articular cartilage samples were prepared from rabbit knees and scanned using ultrasound biomicroscopy (UBM. Three quantitative parameters, including the roughness index of the cartilage surface (URI, the reflection coefficients from the cartilage surface (R and from the cartilage-bone interface (Rbone were extracted. The osteoarthritis grades of these cartilage samples were qualitatively assessed by histology according to the grading standards of International Osteoarthritis Institute (OARSI. The relationship between these quantitative parameters and the osteoarthritis grades was explored. Results The results showed that URI increased with the OA grade. URI of the normal cartilage samples was significantly lower than the one of the OA cartilage samples. There was no significant difference in URI between the grade 1 cartilage samples and the grade 2 cartilage samples. The reflection coefficient of the cartilage surface reduced significantly with the development of OA (p Conclusion High frequency ultrasound measurements can reflect the changes in the surface roughness index and the ultrasound reflection coefficients of the cartilage samples with different OA grades. This study may provide useful information for the quantitative ultrasonic diagnosis of early OA.

  7. Diagnosis of osteoarthritis by cartilage surface smoothness quantified automatically from knee MRI

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    Tummala, Sudhakar; Bay-Jensen, Anne-Christine; Karsdal, Morten A.


    Objective: We investigated whether surface smoothness of articular cartilage in the medial tibiofemoral compartment quantified from magnetic resonance imaging (MRI) could be appropriate as a diagnostic marker of osteoarthritis (OA). Method: At baseline, 159 community-based subjects aged 21 to 81......, specifically cartilage volume from MRI, joint space width (JSW) from radiographs, and pain scores. Results: A total of 140 subjects concluded the 21-month study. Cartilage smoothness provided diagnostic ability in all compartments (P ... with pain severity (e.g., r = -0.32). The longitudinal change in smoothness was correlated with cartilage loss (r up to 0.60, P cartilage smoothness markers for diagnosis of moderate radiographic OA. Furthermore...

  8. Regeneration of Articular Cartilage Surface: Morphogens, Cells, and Extracellular Matrix Scaffolds. (United States)

    Sakata, Ryosuke; Iwakura, Takashi; Reddi, A Hari


    The articular cartilage is a well-organized tissue for smooth and friction-free joint movement for locomotion in animals and humans. Adult articular cartilage has a very low self-regeneration capacity due to its avascular nature. The regeneration of articular cartilage surface is critical to prevent the progression to osteoarthritis (OA). Although various joint resurfacing procedures in experimental articular cartilage defects have been developed, no standardized clinical protocol has yet been established. The three critical ingredients for tissue regeneration are morphogens and growth factors, cells, and scaffolds. The concepts based on the regeneration triad have been extensively investigated in animal models. However, these studies in animal models have demonstrated variable results and outcomes. An optimal animal model must precisely mimic and model the sequence of events in articular cartilage regeneration in human. In this article, the progress and remaining challenges in articular cartilage regeneration in animal models are reviewed. The role of individual morphogens and growth factors in cartilage regeneration has been investigated. In normal articular cartilage homeostasis, morphogens and growth factors function sequentially in tissue regeneration. Mesenchymal stem cell-based repair of articular cartilage defects, performed with or without various growth factors and scaffolds, has been widely attempted in animal models. Stem cells, including embryonic and adult stem cells and induced pluripotent stem cells, have also been reported as attractive cell sources for articular cartilage surface regeneration. Several studies with regard to scaffolds have been advanced, including recent investigations based on nanomaterials, functional mechanocompatible scaffolds, multilayered scaffolds, and extracellular matrix scaffolds for articular cartilage surface regeneration. Continuous refinement of animal models in chondral and osteochondral defects provide opportunities

  9. Solute Transport of Negatively Charged Contrast Agents Across Articular Surface of Injured Cartilage. (United States)

    Kokkonen, H T; Chin, H C; Töyräs, J; Jurvelin, J S; Quinn, T M


    Solute transport through the extracellular matrix (ECM) is crucial to chondrocyte metabolism. Cartilage injury affects solute transport in cartilage due to alterations in ECM structure and solute-matrix interactions. Therefore, cartilage injury may be detected by using contrast agent-based clinical imaging. In the present study, effects of mechanical injury on transport of negatively charged contrast agents in cartilage were characterized. Using cartilage plugs injured by mechanical compression protocol, effective partition coefficients and diffusion fluxes of iodine- and gadolinium-based contrast agents were measured using high resolution microCT imaging. For all contrast agents studied, effective diffusion fluxes increased significantly, particularly at early times during the diffusion process (38 and 33% increase after 4 min, P solute. These findings may help in developing clinical methods of contrast agent-based imaging to detect cartilage injury.

  10. Noninvasive assessment of articular cartilage surface damage using reflected polarized light microscopy (United States)

    Huynh, Ruby N.; Nehmetallah, George; Raub, Christopher B.


    Articular surface damage occurs to cartilage during normal aging, osteoarthritis, and in trauma. A noninvasive assessment of cartilage microstructural alterations is useful for studies involving cartilage explants. This study evaluates polarized reflectance microscopy as a tool to assess surface damage to cartilage explants caused by mechanical scraping and enzymatic degradation. Adult bovine articular cartilage explants were scraped, incubated in collagenase, or underwent scrape and collagenase treatments. In an additional experiment, cartilage explants were subject to scrapes at graduated levels of severity. Polarized reflectance parameters were compared with India ink surface staining, features of histological sections, changes in explant wet weight and thickness, and chondrocyte viability. The polarized reflectance signal was sensitive to surface scrape damage and revealed individual scrape features consistent with India ink marks. Following surface treatments, the reflectance contrast parameter was elevated and correlated with image area fraction of India ink. After extensive scraping, polarized reflectance contrast and chondrocyte viability were lower than that from untreated explants. As part of this work, a mathematical model was developed and confirmed the trend in the reflectance signal due to changes in surface scattering and subsurface birefringence. These results demonstrate the effectiveness of polarized reflectance microscopy to sensitively assess surface microstructural alterations in articular cartilage explants.

  11. Study of the collagen structure in the superficial zone and physiological state of articular cartilage using a 3D confocal imaging technique

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    Zheng Ming H


    Full Text Available Abstract Introduction The collagen structure in the superficial zone of articular cartilage is critical to the tissue's durability. Early osteoarthritis is often characterized with fissures on the articular surface. This is closely related to the disruption of the collagen network. However, the traditional histology can not offer visualization of the collagen structure in articular cartilage because it uses conventional optical microscopy that does not have insufficient imaging resolution to resolve collagen from proteoglycans in hyaline articular cartilage. This study examines the 3D collagen network of articular cartilage scored from 0 to 2 in the scoring system of International Cartilage Repair Society, and aims to develop a 3D histology for assessing early osteoarthritis. Methods Articular cartilage was visually classified into five physiological groups: normal cartilage, aged cartilage, cartilage with artificial and natural surface disruption, and fibrillated. The 3D collagen matrix of the cartilage was acquired using a 3D imaging technique developed previously. Traditional histology was followed to grade the physiological status of the cartilage in the scoring system of International Cartilage Repair Society. Results Normal articular cartilage contains interwoven collagen bundles near the articular surface, approximately within the lamina splendens. However, its collagen fibres in the superficial zone orient predominantly in a direction spatially oblique to the articular surface. With age and disruption of the articular surface, the interwoven collagen bundles are gradually disappeared, and obliquely oriented collagen fibres change to align predominantly in a direction spatially perpendicular to the articular surface. Disruption of the articular surface is well related to the disappearance of the interwoven collagen bundles. Conclusion A 3D histology has been developed to supplement the traditional histology and study the subtle changes in


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    T. A. Stupina


    Full Text Available Purpose of the study — to analyze the changes in knee articular cartilage and synovial membrane during distraction external fixation of the tibia in combination with plating.Material and methods. Articular cartilage and synovial membrane of the knee joint were studied using histomorphometry methods in 9 mongrel dogs during distraction external fixation of the tibia combined with plating. Tibia and fibula osteotomies were performed at the border of middle and upper third, plate was fixed on tibia diaphysis. Lengthening was achieved at rate of 1 mm per day in four stages during 21–28 days. Animals were withdrawn from experiment in 30 and 90 days. After autopsy of knee joints the authors excised sections of synovial membrane from suprapatellar area, articular cartilage with underlying subchondral bone from loadable surface of femoral condyles. Thickness of articular cartilage, its area and volumetric density of chondrocytes was measured, proportion of chondrocytes within isogenic groups from the overall number of chondrocytes as well as proportion of empty lacunae. In synovial membrane the authors measured thickness of surface layer and numeric density of micro vessels. Articular cartilage of 5 intact animals was used as a control group.Results. After 30 days of plate fixation a hyperplasia of the integument layer, mild synovitis, and hypervascularization were observed in synovial membrane. Density of micro vessels increased to 363.93±33.71 (control group — 335.05±28.88. The authors also observed subperineural and endoneural edema as well as destruction of nerve fibers in subsynovial layer. Articular cartilage retained the zonal structure. Destructive changes were manifested by fibers separation in the superficial part of surface zone and by partial loss of chondrocytes. The following parameters were reduced: cartilage thickness, area and volumetric density of chondrocytes, proportion of isogenic groups; empty lacunae exceeded the values in

  13. Surface modification of polycaprolactone scaffolds fabricated via selective laser sintering for cartilage tissue engineering. (United States)

    Chen, Chih-Hao; Lee, Ming-Yih; Shyu, Victor Bong-Hang; Chen, Yi-Chieh; Chen, Chien-Tzung; Chen, Jyh-Ping


    Surface modified porous polycaprolactone scaffolds fabricated via rapid prototyping techniques were evaluated for cartilage tissue engineering purposes. Polycaprolactone scaffolds manufactured by selective laser sintering (SLS) were surface modified through immersion coating with either gelatin or collagen. Three groups of scaffolds were created and compared for both mechanical and biological properties. Surface modification with collagen or gelatin improved the hydrophilicity, water uptake and mechanical strength of the pristine scaffold. From microscopic observations and biochemical analysis, collagen-modified scaffold was the best for cartilage tissue engineering in terms of cell proliferation and extracellular matrix production. Chondrocytes/collagen-modified scaffold constructs were implanted subdermally in the dorsal spaces of female nude mice. Histological and immunohistochemical staining of the retrieved implants after 8 weeks revealed enhanced cartilage tissue formation. We conclude that collagen surface modification through immersion coating on SLS-manufactured scaffolds is a feasible scaffold for cartilage tissue engineering in craniofacial reconstruction. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Nanocomposite scaffold for chondrocyte growth and cartilage tissue engineering: effects of carbon nanotube surface functionalization. (United States)

    Chahine, Nadeen O; Collette, Nicole M; Thomas, Cynthia B; Genetos, Damian C; Loots, Gabriela G


    The goal of this study was to assess the long-term biocompatibility of single-wall carbon nanotubes (SWNTs) for tissue engineering of articular cartilage. We hypothesized that SWNT nanocomposite scaffolds in cartilage tissue engineering can provide an improved molecular-sized substrate for stimulation of chondrocyte growth, as well as structural reinforcement of the scaffold's mechanical properties. The effect of SWNT surface functionalization (-COOH or -PEG) on chondrocyte viability and biochemical matrix deposition was examined in two-dimensional cultures, in three-dimensional (3D) pellet cultures, and in a 3D nanocomposite scaffold consisting of hydrogels+SWNTs. Outcome measures included cell viability, histological and SEM evaluation, GAG biochemical content, compressive and tensile biomechanical properties, and gene expression quantification, including extracellular matrix (ECM) markers aggrecan (Agc), collagen-1 (Col1a1), collagen-2 (Col2a1), collagen-10 (Col10a1), surface adhesion proteins fibronectin (Fn), CD44 antigen (CD44), and tumor marker (Tp53). Our findings indicate that chondrocytes tolerate functionalized SWNTs well, with minimal toxicity of cells in 3D culture systems (pellet and nanocomposite constructs). Both SWNT-PEG and SWNT-COOH groups increased the GAG content in nanocomposites relative to control. The compressive biomechanical properties of cell-laden SWNT-COOH nanocomposites were significantly elevated relative to control. Increases in the tensile modulus and ultimate stress were observed, indicative of a tensile reinforcement of the nanocomposite scaffolds. Surface coating of SWNTs with -COOH also resulted in increased Col2a1 and Fn gene expression throughout the culture in nanocomposite constructs, indicative of increased chondrocyte metabolic activity. In contrast, surface coating of SWNTs with a neutral -PEG moiety had no significant effect on Col2a1 or Fn gene expression, suggesting that the charged nature of the -COOH surface

  15. MRI based knee cartilage assessment (United States)

    Kroon, Dirk-Jan; Kowalski, Przemyslaw; Tekieli, Wojciech; Reeuwijk, Els; Saris, Daniel; Slump, Cornelis H.


    Osteoarthritis is one of the leading causes of pain and disability worldwide and a major health problem in developed countries due to the gradually aging population. Though the symptoms are easily recognized and described by a patient, it is difficult to assess the level of damage or loss of articular cartilage quantitatively. We present a novel method for fully automated knee cartilage thickness measurement and subsequent assessment of the knee joint. First, the point correspondence between a pre-segmented training bone model is obtained with use of Shape Context based non-rigid surface registration. Then, a single Active Shape Model (ASM) is used to segment both Femur and Tibia bone. The surfaces obtained are processed to extract the Bone-Cartilage Interface (BCI) points, where the proper segmentation of cartilage begins. For this purpose, the cartilage ASM is trained with cartilage edge positions expressed in 1D coordinates at the normals in the BCI points. The whole cartilage model is then constructed from the segmentations obtained in the previous step. An absolute thickness of the segmented cartilage is measured and compared to the mean of all training datasets, giving as a result the relative thickness value. The resulting cartilage structure is visualized and related to the segmented bone. In this way the condition of the cartilage is assessed over the surface. The quality of bone and cartilage segmentation is validated and the Dice's coefficients 0.92 and 0.86 for Femur and Tibia bones and 0.45 and 0.34 for respective cartilages are obtained. The clinical diagnostic relevance of the obtained thickness mapping is being evaluated retrospectively. We hope to validate it prospectively for prediction of clinical outcome the methods require improvements in accuracy and robustness.

  16. Gelatin Scaffolds with Controlled Pore Structure and Mechanical Property for Cartilage Tissue Engineering. (United States)

    Chen, Shangwu; Zhang, Qin; Nakamoto, Tomoko; Kawazoe, Naoki; Chen, Guoping


    Engineering of cartilage tissue in vitro using porous scaffolds and chondrocytes provides a promising approach for cartilage repair. However, nonuniform cell distribution and heterogeneous tissue formation together with weak mechanical property of in vitro engineered cartilage limit their clinical application. In this study, gelatin porous scaffolds with homogeneous and open pores were prepared using ice particulates and freeze-drying. The scaffolds were used to culture bovine articular chondrocytes to engineer cartilage tissue in vitro. The pore structure and mechanical property of gelatin scaffolds could be well controlled by using different ratios of ice particulates to gelatin solution and different concentrations of gelatin. Gelatin scaffolds prepared from ≥70% ice particulates enabled homogeneous seeding of bovine articular chondrocytes throughout the scaffolds and formation of homogeneous cartilage extracellular matrix. While soft scaffolds underwent cellular contraction, stiff scaffolds resisted cellular contraction and had significantly higher cell proliferation and synthesis of sulfated glycosaminoglycan. Compared with the gelatin scaffolds prepared without ice particulates, the gelatin scaffolds prepared with ice particulates facilitated formation of homogeneous cartilage tissue with significantly higher compressive modulus. The gelatin scaffolds with highly open pore structure and good mechanical property can be used to improve in vitro tissue-engineered cartilage.

  17. Arthroscopic Fixation of Cell Free Polymer-Based Cartilage Implants with a Bioinspired Polymer Surface on the Hip Joint: A Cadaveric Pilot Study

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    Matthias Lahner


    Full Text Available This study investigates the adhesion capacity of a polyglycolic acid- (PGA- hyaluronan scaffold with a structural modification based on a planar polymer (PM surface in a cadaver cartilage defect model. Two cadaver specimens were used to serially test multiple chondral matrices. In a cadaver hip model, cell free polymer-based cartilage implants with a planar bioinspired PM surface (PGA-PM-scaffolds were implanted arthroscopically on 10 mm × 15 mm full-thickness femoral hip cartilage lesions. Unprocessed cartilage implants without a bioinspired PM surface were used as control group. The cartilage implants were fixed without and with the use of fibrin glue on femoral hip cartilage defects. After 50 movement cycles and removal of the distraction, a rearthroscopy was performed to assess the outline attachment and integrity of the scaffold. The fixation techniques without and with fibrin fixation showed marginal differences for outline attachment, area coverage, scaffold integrity, and endpoint fixation after 50 cycles. The PGA-PM-scaffolds with fibrin fixation achieved a higher score in terms of the attachment, integrity, and endpoint fixation than the PGA-scaffold on the cartilage defect. Relating to the outline attachment, area coverage, scaffold integrity, and endpoint fixation, the fixation with PGA-PM-scaffolds accomplished significantly better results compared to the PGA-scaffolds (P=0.03752, P=0.03078, P=0.00512, P=0.00512. PGA-PM-scaffolds demonstrate increased observed initial fixation strength in cadaver femoral head defects relative to PGA-scaffold, particularly when fibrin glue is used for fixation.

  18. Compositional and structural studies of the bone-cartilage interface using PIXE and SAXS techniques

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    Kaabar, W., E-mail: [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Laklouk, A. [Al-Fateh University, Tripoli-Libya (Libyan Arab Jamahiriya); Bunk, O. [Swiss Light Source, Paul Scherrer Institute, 5232 Villigen (Switzerland); Baily, M. [Department of Medical Physics and Applied Radiation Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada, L8S 4K1 (Canada); Farquharson, M.J. [Surrey Ion Beam Centre, University of Surrey, Guildford, GU2 7XH (United Kingdom); Bradley, David [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom)


    Micro-proton-induced X-ray emission ({mu}-PIXE) analysis has been employed in investigating the presence of number of essential anions and cations in thin sections of diseased human articular cartilage affected by osteoarthritis (OA). Distribution maps for Ca, P, K and S in diseased sections show marked alterations in the concentrations of these at the bone-cartilage interface compared to normal tissue. For a decalcified section of human articular cartilage, organisational changes of the collagen network were investigated by small-angle X-ray scattering (SAXS). The established gradual reorientation of collagen fibres from vertical to the surface of the joint to normal to the bone-cartilage interface is observed to be heavily disrupted in OA.

  19. Accuracy evaluation of automatic quantification of the articular cartilage surface curvature from MRI

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    Folkesson, Jenny; Dam, Erik B; Olsen, Ole F


    RATIONALE AND OBJECTIVES: To study the articular cartilage surface curvature determined automatically from magnetic resonance (MR) knee scans, evaluate accuracy of the curvature estimates on digital phantoms, and an evaluation of their potential as disease markers for different stages of osteoart......RATIONALE AND OBJECTIVES: To study the articular cartilage surface curvature determined automatically from magnetic resonance (MR) knee scans, evaluate accuracy of the curvature estimates on digital phantoms, and an evaluation of their potential as disease markers for different stages...... for intersubject comparisons. Digital phantoms were created to establish the accuracy of the curvature estimation methods. RESULTS: A comparison of the two curvature estimation methods to ground truth yielded absolute pairwise differences of 1.1%, and 4.8%, respectively. The interscan reproducibility for the two...

  20. Microstructural analysis of collagen and elastin fibres in the kangaroo articular cartilage reveals a structural divergence depending on its local mechanical environment. (United States)

    He, B; Wu, J P; Chim, S M; Xu, J; Kirk, T B


    To assess the microstructure of the collagen and elastin fibres in articular cartilage under different natural mechanical loading conditions and determine the relationship between the microstructure of collagen and its mechanical environment. Articular cartilage specimens were collected from the load bearing regions of the medial femoral condyle and the medial distal humerus of adult kangaroos. The microstructure of collagen and elastin fibres of these specimens was studied using laser scanning confocal microscopy (LSCM) and the orientation and texture features of the collagen were analysed using ImageJ. A zonal arrangement of collagen was found in kangaroo articular cartilage: the collagen fibres aligned parallel to the surface in the superficial zone and ran perpendicular in the deep zone. Compared with the distal humerus, the collagen in the femoral condyle was less isotropic and more clearly oriented, especially in the superficial and deep zones. The collagen in the femoral condyle was highly heterogeneous, less linear and more complex. Elastin fibres were found mainly in the superficial zone of the articular cartilage of both femoral condyle and distal humerus. The present study demonstrates that the collagen structure and texture of kangaroo articular cartilage is joint-dependent. This finding emphasizes the effects of loading on collagen development and suggests that articular cartilage with high biochemical and biomechanical qualities could be achieved by optimizing joint loading, which may benefit cartilage tissue engineering and prevention of joint injury. The existence of elastin fibres in articular cartilage could have important functional implications. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  1. Unsaturated phosphatidylcholines lining on the surface of cartilage and its possible physiological roles

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    Crawford Ross W


    Full Text Available Abstract Background Evidence has strongly indicated that surface-active phospholipid (SAPL, or surfactant, lines the surface of cartilage and serves as a lubricating agent. Previous clinical study showed that a saturated phosphatidylcholine (SPC, dipalmitoyl-phosphatidylcholine (DPPC, was effective in the treatment of osteoarthritis, however recent studies suggested that the dominant SAPL species at some sites outside the lung are not SPC, rather, are unsaturated phosphatidylcholine (USPC. Some of these USPC have been proven to be good boundary lubricants by our previous study, implicating their possible important physiological roles in joint if their existence can be confirmed. So far, no study has been conducted to identify the whole molecule species of different phosphatidylcholine (PC classes on the surface of cartilage. In this study we identified the dominant PC molecule species on the surface of cartilage. We also confirmed that some of these PC species possess a property of semipermeability. Methods HPLC was used to analyse the PC profile of bovine cartilage samples and comparisons of DPPC and USPC were carried out through semipermeability tests. Results It was confirmed that USPC are the dominant SAPL species on the surface of cartilage. In particular, they are Dilinoleoyl-phosphatidylcholine (DLPC, Palmitoyl-linoleoyl-phosphatidylcholine, (PLPC, Palmitoyl-oleoyl-phosphatidylcholine (POPC and Stearoyl-linoleoyl-phosphatidylcholine (SLPC. The relative content of DPPC (a SPC was only 8%. Two USPC, PLPC and POPC, were capable of generating osmotic pressure that is equivalent to that by DPPC. Conclusion The results from the current study confirm vigorously that USPC is the endogenous species inside the joint as against DPPC thereby confirming once again that USPC, and not SPC, characterizes the PC species distribution at non-lung sites of the body. USPC not only has better anti-friction and lubrication properties than DPPC, they also

  2. Chondroitin sulfate immobilization at the surface of electrospun nanofiber meshes for cartilage tissue regeneration approaches (United States)

    Piai, Juliana Francis; da Silva, Marta Alves; Martins, Albino; Torres, Ana Bela; Faria, Susana; Reis, Rui L.; Muniz, Edvani Curti; Neves, Nuno M.


    Aiming at improving the biocompatibility of biomaterial scaffolds, surface modification presents a way to preserve their mechanical properties and to improve the surface bioactivity. In this work, chondroitin sulfate (CS) was immobilized at the surface of electrospun poly(caprolactone) nanofiber meshes (PCL NFMs), previously functionalized by UV/O3 exposure and aminolysis. Contact angle, SEM, optical profilometry, FTIR, X-ray photoelectron spectroscopy techniques confirmed the success of CS-immobilization in PCL NFMs. Furthermore, CS-immobilized PCL NFMs showed lower roughness and higher hydrophilicity than the samples without CS. Human articular chondrocytes (hACs) were cultured on electrospun PCL NFMs with or without CS immobilization. It was observed that hACs proliferated through the entire time course of the experiment in both types of nanofibrous scaffolds, as well as for the production of glycosaminoglycans. Quantitative-PCR results demonstrated over-expression of cartilage-related genes such as Aggrecan, Collagen type II, COMP and Sox9 on both types of nanofibrous scaffolds. Morphological observations from SEM and LSCM revealed that hACs maintained their characteristic round shape and cellular agglomeration exclusively on PCL NFMs with CS immobilization. In conclusion, CS immobilization at the surface of PCL NFMs was achieved successfully and provides a valid platform enabling further surface functionalization methods in scaffolds to be developed for cartilage tissue engineering.

  3. Development of a Spring-Loaded Impact Device to Deliver Injurious Mechanical Impacts to the Articular Cartilage Surface (United States)

    Alexander, Peter G.; Song, Yingjie; Taboas, Juan M.; Chen, Faye H.; Melvin, Gary M.; Manner, Paul A.


    Objective: Traumatic impacts on the articular joint surface in vitro are known to lead to degeneration of the cartilage. The main objective of this study was to develop a spring-loaded impact device that can be used to deliver traumatic impacts of consistent magnitude and rate and to find whether impacts cause catabolic activities in articular cartilage consistent with other previously reported impact models and correlated with the development of osteoarthritic lesions. In developing the spring-loaded impactor, the operating hypothesis is that a single supraphysiologic impact to articular cartilage in vitro can affect cartilage integrity, cell viability, sulfated glycosaminoglycan and inflammatory mediator release in a dose-dependent manner. Design: Impacts of increasing force are delivered to adult bovine articular cartilage explants in confined compression. Impact parameters are correlated with tissue damage, cell viability, matrix and inflammatory mediator release, and gene expression 24 hours postimpact. Results: Nitric oxide release is first detected after 7.7 MPa impacts, whereas cell death, glycosaminoglycan release, and prostaglandin E2 release are first detected at 17 MPa. Catabolic markers increase linearly to maximal levels after ≥36 MPa impacts. Conclusions: A single supraphysiologic impact negatively affects cartilage integrity, cell viability, and GAG release in a dose-dependent manner. Our findings showed that 7 to 17 MPa impacts can induce cell death and catabolism without compromising the articular surface, whereas a 17 MPa impact is sufficient to induce increases in most common catabolic markers of osteoarthritic degeneration. PMID:26069650

  4. Importance of Patella, Quadriceps Forces, and Depthwise Cartilage Structure on Knee Joint Motion and Cartilage Response During Gait. (United States)

    Halonen, K S; Mononen, M E; Jurvelin, J S; Töyräs, J; Klodowski, A; Kulmala, J-P; Korhonen, R K


    In finite-element (FE) models of the knee joint, patella is often omitted. We investigated the importance of patella and quadriceps forces on the knee joint motion by creating an FE model of the subject's knee. In addition, depthwise strains and stresses in patellar cartilage with different tissue properties were determined. An FE model was created from subject's magnetic resonance images. Knee rotations, moments, and translational forces during gait were recorded in a motion laboratory and used as an input for the model. Three material models were implemented into the patellar cartilage: (1) homogeneous model, (2) inhomogeneous (arcadelike fibrils), and (3) random fibrils at the superficial zone, mimicking early stages of osteoarthritis (OA). Implementation of patella and quadriceps forces into the model substantially reduced the internal-external femoral rotations (versus without patella). The simulated rotations in the model with the patella matched the measured rotations at its best. In the inhomogeneous model, maximum principal stresses increased substantially in the middle zone of the cartilage. The early OA model showed increased compressive strains in the superficial and middle zones of the cartilage and decreased stresses and fibril strains especially in the middle zone. The results suggest that patella and quadriceps forces should be included in moment- and force-driven FE knee joint models. The results indicate that the middle zone has a major role in resisting shear forces in the patellar cartilage. Also, early degenerative changes in the collagen network substantially affect the cartilage depthwise response in the patella during walking.

  5. Robust and general method for determining surface fluid flow boundary conditions in articular cartilage contact mechanics modeling. (United States)

    Pawaskar, Sainath Shrikant; Fisher, John; Jin, Zhongmin


    Contact detection in cartilage contact mechanics is an important feature of any analytical or computational modeling investigation when the biphasic nature of cartilage and the corresponding tribology are taken into account. The fluid flow boundary conditions will change based on whether the surface is in contact or not, which will affect the interstitial fluid pressurization. This in turn will increase or decrease the load sustained by the fluid phase, with a direct effect on friction, wear, and lubrication. In laboratory experiments or clinical hemiarthroplasty, when a rigid indenter or metallic prosthesis is used to apply load to the cartilage, there will not be any fluid flow normal to the surface in the contact region due to the impermeable nature of the indenter/prosthesis. In the natural joint, on the other hand, where two cartilage surfaces interact, flow will depend on the pressure difference across the interface. Furthermore, in both these cases, the fluid would flow freely in non-contacting regions. However, it should be pointed out that the contact area is generally unknown in advance in both cases and can only be determined as part of the solution. In the present finite element study, a general and robust algorithm was proposed to decide nodes in contact on the cartilage surface and, accordingly, impose the fluid flow boundary conditions. The algorithm was first tested for a rigid indenter against cartilage model. The algorithm worked well for two-dimensional four-noded and eight-noded axisymmetric element models as well as three-dimensional models. It was then extended to include two cartilages in contact. The results were in excellent agreement with the previous studies reported in the literature.

  6. Tensorial Electrokinetics in Articular Cartilage (United States)

    Reynaud, Boris; Quinn, Thomas M.


    Electrokinetic phenomena contribute to biomechanical functions of articular cartilage and underlie promising methods for early detection of osteoarthritic lesions. Although some transport properties, such as hydraulic permeability, are known to become anisotropic with compression, the direction-dependence of cartilage electrokinetic properties remains unknown. Electroosmosis experiments were therefore performed on adult bovine articular cartilage samples, whereby fluid flows were driven by electric currents in directions parallel and perpendicular to the articular surface of statically compressed explants. Magnitudes of electrokinetic coefficients decreased slightly with compression (from ∼−7.5 μL/As in the range of 0–20% compression to −6.0 μL/As in the 35–50% range) consistent with predictions of microstructure-based models of cartilage material properties. However, no significant dependence on direction of the electrokinetic coupling coefficient was detected, even for conditions where the hydraulic permeability tensor is known to be anisotropic. This contrast may also be interpreted using microstructure-based models, and provides insights into structure-function relationships in cartilage extracellular matrix and physical mediators of cell responses to tissue compression. Findings support the use of relatively simple isotropic modeling approaches for electrokinetic phenomena in cartilage and related materials, and indicate that measurement of electrokinetic properties may provide particularly robust means for clinical evaluation of cartilage matrix integrity. PMID:16798804

  7. Development of Scaffold-Free Elastic Cartilaginous Constructs with Structural Similarities to Auricular Cartilage (United States)

    Giardini-Rosa, Renata; Joazeiro, Paulo P.; Thomas, Kathryn; Collavino, Kristina; Weber, Joanna


    External ear reconstruction with autologous cartilage still remains one of the most difficult problems in the fields of plastic and reconstructive surgery. As the absence of tissue vascularization limits the ability to stimulate new tissue growth, relatively few surgical approaches are currently available (alloplastic implants or sculpted autologous cartilage grafts) to repair or reconstruct the auricle (or pinna) as a result of traumatic loss or congenital absence (e.g., microtia). Alternatively, tissue engineering can offer the potential to grow autogenous cartilage suitable for implantation. While tissue-engineered auricle cartilage constructs can be created, a substantial number of cells are required to generate sufficient quantities of tissue for reconstruction. Similarly, as routine cell expansion can elicit negative effects on chondrocyte function, we have developed an approach to generate large-sized engineered auricle constructs (≥3 cm2) directly from a small population of donor cells (20,000–40,000 cells/construct). Using rabbit donor cells, the developed bioreactor-cultivated constructs adopted structural-like characteristics similar to native auricular cartilage, including the development of distinct cartilaginous and perichondrium-like regions. Both alterations in media composition and seeding density had profound effects on the formation of engineered elastic tissue constructs in terms of cellularity, extracellular matrix accumulation, and tissue structure. Higher seeding densities and media containing sodium bicarbonate produced tissue constructs that were closer to the native tissue in terms of structure and composition. Future studies will be aimed at improving the accumulation of specific tissue constituents and determining the clinical effectiveness of this approach using a reconstructive animal model. PMID:24124666

  8. Structural reorganization of the knee joint cartilage and synovium during diaphyseal femoral fracture management using intramedullary locked nails ^perime^al and morphological study

    Directory of Open Access Journals (Sweden)

    A. A. Emanov


    Full Text Available The purpose - to study structural changes in knee articular cartilage and synovial membrane during locking intramedullary osteosynthesis of femoral fractures. Material and methods. The study tested structural changes in the articular cartilage of the femoral condyles and synovium during femoral fracture repair under the conditions of intramedullary locked nailing. Transverse diaphyseal femoral fractures were modeled in 12 adult mongrel dogs. Synovitis severity was assessed with a V. Krenn scale. Wilcoxon Test was used for testing hypothesis. Results. In the first group (n = 6 fractures were fixed with locked intramedullary nails ILoc (Biomedtrix, USA, while the same type of fixation in group 2 (n = 6 was performed on 4th day postoperatively after reduction by skeletal traction. It was revealed that in the first group a unified medullary cavity was seen by day 70 and the cortical layer at the fracture site approximated to the condition of the uninjured bone in intensity of bone formation and thickness. These featured were observed in the second group only by day 100. The histological study showed that the structure of the femoral condyle articular cartilage was regular in the first group but its changes were reduced thickness and reduced volumetric density of chondrocytes that might result due to disturbed trophical condition. In the second group the articular cartilage fibres tended to disintegrate on the surface that was accompanied by disturbed integrity of the basophil line and penetration of the vessels into the cartilage. Moreover, the cartilage destruction progressed as the experiment continued and chondrocyte proliferation sharply decreased. Synovitis was considerably expressed. The data obtained in the second group proved high risk of developing osteoarthrosis.

  9. Chondroitin sulfate immobilization at the surface of electrospun nanofiber meshes for cartilage tissue regeneration approaches

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    Piai, Juliana Francis [3B’s Research Group − Biomaterials, Biodegradables and Biomimetics, Department of Polymer Engineering, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, 4805-017 Barco, Guimarães (Portugal); ICVS/3B’s − PT Government Associate Laboratory, Braga/Guimarães (Portugal); Grupo de Materiais Poliméricos e Compósitos, GMPC – Departamento de Química- Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900, Maringá, Paraná (Brazil); Alves da Silva, Marta; Martins, Albino; Torres, Ana Bela [3B’s Research Group − Biomaterials, Biodegradables and Biomimetics, Department of Polymer Engineering, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, 4805-017 Barco, Guimarães (Portugal); ICVS/3B’s − PT Government Associate Laboratory, Braga/Guimarães (Portugal); Faria, Susana [Research Center Officinal Mathematical, Department of Mathematics for Science and Technology, University of Minho, Campus de Azurém, 4800-058 Guimarães (Portugal); and others


    Highlights: • Chemical immobilization of chondroitin sulfate at the surface of nanofiber meshes. • CS-immobilized NFMs showed lower roughness and higher hydrophilicity. • CS-immobilized NFMs offer a highly effective substrate for hACs phenotypic stability. - Abstract: Aiming at improving the biocompatibility of biomaterial scaffolds, surface modification presents a way to preserve their mechanical properties and to improve the surface bioactivity. In this work, chondroitin sulfate (CS) was immobilized at the surface of electrospun poly(caprolactone) nanofiber meshes (PCL NFMs), previously functionalized by UV/O{sub 3} exposure and aminolysis. Contact angle, SEM, optical profilometry, FTIR, X-ray photoelectron spectroscopy techniques confirmed the success of CS-immobilization in PCL NFMs. Furthermore, CS-immobilized PCL NFMs showed lower roughness and higher hydrophilicity than the samples without CS. Human articular chondrocytes (hACs) were cultured on electrospun PCL NFMs with or without CS immobilization. It was observed that hACs proliferated through the entire time course of the experiment in both types of nanofibrous scaffolds, as well as for the production of glycosaminoglycans. Quantitative-PCR results demonstrated over-expression of cartilage-related genes such as Aggrecan, Collagen type II, COMP and Sox9 on both types of nanofibrous scaffolds. Morphological observations from SEM and LSCM revealed that hACs maintained their characteristic round shape and cellular agglomeration exclusively on PCL NFMs with CS immobilization. In conclusion, CS immobilization at the surface of PCL NFMs was achieved successfully and provides a valid platform enabling further surface functionalization methods in scaffolds to be developed for cartilage tissue engineering.

  10. Growth factor stimulation improves the structure and properties of scaffold-free engineered auricular cartilage constructs.

    Directory of Open Access Journals (Sweden)

    Renata G Rosa

    Full Text Available The reconstruction of the external ear to correct congenital deformities or repair following trauma remains a significant challenge in reconstructive surgery. Previously, we have developed a novel approach to create scaffold-free, tissue engineering elastic cartilage constructs directly from a small population of donor cells. Although the developed constructs appeared to adopt the structural appearance of native auricular cartilage, the constructs displayed limited expression and poor localization of elastin. In the present study, the effect of growth factor supplementation (insulin, IGF-1, or TGF-β1 was investigated to stimulate elastogenesis as well as to improve overall tissue formation. Using rabbit auricular chondrocytes, bioreactor-cultivated constructs supplemented with either insulin or IGF-1 displayed increased deposition of cartilaginous ECM, improved mechanical properties, and thicknesses comparable to native auricular cartilage after 4 weeks of growth. Similarly, growth factor supplementation resulted in increased expression and improved localization of elastin, primarily restricted within the cartilaginous region of the tissue construct. Additional studies were conducted to determine whether scaffold-free engineered auricular cartilage constructs could be developed in the 3D shape of the external ear. Isolated auricular chondrocytes were grown in rapid-prototyped tissue culture molds with additional insulin or IGF-1 supplementation during bioreactor cultivation. Using this approach, the developed tissue constructs were flexible and had a 3D shape in very good agreement to the culture mold (average error <400 µm. While scaffold-free, engineered auricular cartilage constructs can be created with both the appropriate tissue structure and 3D shape of the external ear, future studies will be aimed assessing potential changes in construct shape and properties after subcutaneous implantation.

  11. Micrometer scale guidance of mesenchymal stem cells to form structurally oriented cartilage extracellular matrix. (United States)

    Chou, Chih-Ling; Rivera, Alexander L; Sakai, Takao; Caplan, Arnold I; Goldberg, Victor M; Welter, Jean F; Baskaran, Harihara


    Tissue engineering is a possible method for long-term repair of cartilage lesions, but current tissue-engineered cartilage constructs have inferior mechanical properties compared to native cartilage. This problem may be due to the lack of an oriented structure in the constructs at the microscale that is present in the native tissue. In this study, we utilize contact guidance to develop constructs with microscale architecture for improved chondrogenesis and function. Stable channels of varying microscale dimensions were formed in collagen-based and polydimethylsiloxane membranes via a combination of microfabrication and soft-lithography. Human mesenchymal stem cells (MSCs) were selectively seeded in these channels. The chondrogenic potential of MSCs seeded in these channels was investigated by culturing them for 3 weeks under differentiating conditions, and then evaluating the subsequent synthesized tissue for mechanical function and by type II collagen immunohistochemistry. We demonstrate selective seeding of viable MSCs within the channels. MSC aligned and produced mature collagen fibrils along the length of the channel in smaller linear channels of widths 25-100 μm compared to larger linear channels of widths 500-1000 μm. Further, substrates with microchannels that led to cell alignment also led to superior mechanical properties compared to constructs with randomly seeded cells or selectively seeded cells in larger channels. The ultimate stress and modulus of elasticity of constructs with cells seeded in smaller channels increased by as much as fourfolds. We conclude that microscale guidance is useful to produce oriented cartilage structures with improved mechanical properties. These findings can be used to fabricate large clinically useful MSC-cartilage constructs with superior mechanical properties.

  12. Structural and Anatomic Restoration of the Anterior Cruciate Ligament Is Associated With Less Cartilage Damage 1 Year After Surgery: Healing Ligament Properties Affect Cartilage Damage (United States)

    Kiapour, Ata M.; Fleming, Braden C.; Murray, Martha M.


    Background: Abnormal joint motion has been linked to joint arthrosis after anterior cruciate ligament (ACL) reconstruction. However, the relationships between the graft properties (ie, structural and anatomic) and extent of posttraumatic osteoarthritis are not well defined. Hypotheses: (1) The structural (tensile) and anatomic (area and alignment) properties of the reconstructed graft or repaired ACL correlate with the total cartilage lesion area 1 year after ACL surgery, and (2) side-to-side differences in anterior-posterior (AP) knee laxity correlate with the total cartilage lesion area 1 year postoperatively. Study Design: Controlled laboratory study. Methods: Sixteen minipigs underwent unilateral ACL transection and were randomly treated with ACL reconstruction or bridge-enhanced ACL repair. The tensile properties, cross-sectional area, and multiplanar alignment of the healing ACL or graft, AP knee laxity, and cartilage lesion areas were assessed 1 year after surgery. Results: In the reconstructed group, the normalized graft yield and maximum failure loads, cross-sectional area, sagittal and coronal elevation angles, and side-to-side differences in AP knee laxity at 60° of flexion were associated with the total cartilage lesion area 1 year after surgery (R 2 > 0.5, P 0.5, P ligament or graft and AP laxity values were closer to those of the contralateral ACL-intact knee. Reconstructed grafts had a significantly larger normalized cross-sectional area and sagittal elevation angle (more vertical) when compared with repaired ACLs (P < .02). Conclusion: The tensile properties, cross-sectional area, and multiplanar alignment of the healing ACLs or grafts and AP knee laxity in reconstructed knees were associated with the extent of tibiofemoral cartilage damage after ACL surgery. Clinical Relevance: These data highlight the need for novel ACL injury treatments that can restore the structural and anatomic properties of the torn ACL to those of the native ACL in an

  13. Study on nano-structured hydroxyapatite/zirconia stabilized yttria on healing of articular cartilage defect in rabbit

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    Amir Sotoudeh


    Full Text Available PURPOSE: Articular Cartilage has limited potential for self-repair and tissue engineering approaches attempt to repair articular cartilage by scaffolds. We hypothesized that the combined hydroxyapatite and zirconia stabilized yttria would enhance the quality of cartilage healing. METHODS: In ten New Zealand white rabbits bilateral full-thickness osteochondral defect, 4 mm in diameter and 3 mm depth, was created on the articular cartilage of the patellar groove of the distal femur. In group I the scaffold was implanted into the right stifle and the same defect was created in the left stifle without any transplant (group II. Specimens were harvested at 12 weeks after implantation, examined histologically for morphologic features, and stained immunohistochemically for type-II collagen. RESULTS: In group I the defect was filled with a white translucent cartilage tissue In contrast, the defects in the group II remained almost empty. In the group I, the defects were mostly filled with hyaline-like cartilage evidenced but defects in group II were filled with fibrous tissue with surface irregularities. Positive immunohistochemical staining of type-II collagen was observed in group I and it was absent in the control group. CONCLUSION: The hydroxyapatite/yttria stabilized zirconia scaffold would be an effective scaffold for cartilage tissue engineering.

  14. Cartilage constructs from human cord blood stem cells seeded in structurally-graded polycaprolactone scaffolds

    DEFF Research Database (Denmark)

    Munir, Samir; Koch, Thomas Gadegaard; Foldager, Casper Bindzus

    stimulation. This study demonstrated the chondrogenic potential of human cord blood-derived Multi-Lineage Progenitor Cells (MLPCs) under normoxic and hypoxic culture conditions. Second, MLPCs were seeded in a novel, structurally graded polycaprolactone (SGS-PCL) scaffold and chondrogenesis was evaluated......, safranin O), glycosaminoglycan (GAG) protein secretion, and gene expression of cartilage markers. Based on this data, MLPCs were seeded in SGS-PCL scaffolds and cultured under optimal oxygen tension for 21 days followed by chondrogenic evaluation as above. Porous SGS-PCL scaffolds were provided by i...... tensions. Histological sections revealed a cartilaginous struc¬ture as recognized by chondrocyte-like cells embedded in lacunae. Histological sections of control pellets did not stain for GAG nor show a cartilage-like morphology. Gene expression analyses (qRT-PCR), GAG protein secretion, and histology...

  15. Structure and composition of arytenoid cartilage of the bullfrog (Lithobates catesbeianus) during maturation and aging. (United States)

    Laureano, Priscila Eliane dos Santos; Oliveira, Kris Daiana Silva; de Aro, Andrea Aparecida; Gomes, Laurecir; Pimentel, Edson Rosa; Esquisatto, Marcelo Augusto Marretto


    The aging process induces progressive and irreversible changes in the structural and functional organization of animals. The objective of this study was to evaluate the effects of aging on the structure and composition of the extracellular matrix of the arytenoid cartilage found in the larynx of male bullfrogs (Lithobates catesbeianus) kept in captivity for commercial purposes. Animals at 7, 180 and 1080 days post-metamorphosis (n=10/age) were euthanized and the cartilage was removed and processed for structural and biochemical analysis. For the structural analyses, cartilage sections were stained with picrosirius, toluidine blue, Weigert's resorcin-fuchsin and Von Kossa stain. The sections were also submitted to immunohistochemistry for detection of collagen types I and II. Other samples were processed for the ultrastructural and cytochemical analysis of proteoglycans. Histological sections were used to chondrocyte count. The number of positive stainings for proteoglycans was quantified by ultrastructural analysis. For quantification and analysis of glycosaminoglycans were used the dimethyl methylene blue and agarose gel electrophoresis methods. The chloramine T method was used for hydroxyproline quantification. At 7 days, basophilia was observed in the pericellular and territorial matrix, which decreased in the latter over the period studied. Collagen fibers were arranged perpendicular to the major axis of the cartilaginous plate and were thicker in older animals. Few calcification areas were observed at the periphery of the cartilage specimens in 1080-day-old animals. Type II collagen was present throughout the stroma at the different ages. Elastic fibers were found in the stroma and perichondrium and increased with age in the two regions. Proteoglycan staining significantly increased from 7 to 180 days and reduced at 1080 days. The amount of total glycosaminoglycans was higher in 180-day-old animals compared to the other ages, with marked presence of

  16. Synthesis and characterization of a lubricin mimic (mLub) to reduce friction and adhesion on the articular cartilage surface. (United States)

    Lawrence, Alexandra; Xu, Xin; Bible, Melissa D; Calve, Sarah; Neu, Corey P; Panitch, Alyssa


    The lubricating proteoglycan, lubricin, facilitates the remarkable low friction and wear properties of articular cartilage in the synovial joints of the body. Lubricin lines the joint surfaces and plays a protective role as a boundary lubricant in sliding contact; decreased expression of lubricin is associated with cartilage degradation and the pathogenesis of osteoarthritis. An unmet need for early osteoarthritis treatment is the development of therapeutic molecules that mimic lubricin function and yet are also resistant to enzymatic degradation common in the damaged joint. Here, we engineered a lubricin mimic (mLub) that is less susceptible to enzymatic degradation and binds to the articular surface to reduce friction. mLub was synthesized using a chondroitin sulfate backbone with type II collagen and hyaluronic acid (HA) binding peptides to promote interaction with the articular surface and synovial fluid constituents. In vitro and in vivo characterization confirmed the binding ability of mLub to isolated type II collagen and HA, and to the cartilage surface. Following trypsin treatment to the cartilage surface, application of mLub, in combination with purified or commercially available hyaluronan, reduced the coefficient of friction, and adhesion, to control levels as assessed over macro-to micro-scales by rheometry and atomic force microscopy. In vivo studies demonstrate an mLub residency time of less than 1 week. Enhanced lubrication by mLub reduces surface friction and adhesion, which may suppress the progression of degradation and cartilage loss in the joint. mLub therefore shows potential for treatment in early osteoarthritis following injury. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Structural changes in cartilage and collagen studied by high temperature Raman spectroscopy. (United States)

    Fields, Mark; Spencer, Nicholas; Dudhia, Jayesh; McMillan, Paul F


    Understanding the high temperature behavior of collagen and collagenous tissue is important for surgical procedures and biomaterials processing for the food, pharmaceutical, and cosmetics industries. One primary event for proteins is thermal denaturation that involves unfolding the polypeptide chains while maintaining the primary structure intact. Collagen in the extracellular matrix of cartilage and other connective tissue is a hierarchical material containing bundles of triple-helical fibers associated with water and proteoglycan components. Thermal analysis of dehydrated collagen indicates irreversible denaturation at high temperature between 135°C and 200°C, with another reversible event at ∼60-80°C for hydrated samples. We report high temperature Raman spectra for freeze-dried cartilage samples that show an increase in laser-excited fluorescence interpreted as conformational changes associated with denaturation above 140°C. Spectra for separated collagen and proteoglycan fractions extracted from cartilage indicate the changes are associated with collagen. The Raman data also show appearance of new features indicating peptide bond hydrolysis at high temperature implying that molecular H2 O is retained within the freeze-dried tissue. This is confirmed by thermogravimetric analysis that show 5-7 wt% H2 O remaining within freeze-dried cartilage that is released progressively upon heating up to 200°C. Spectra obtained after exposure to high temperature and re-hydration following recovery indicate that the capacity of the denatured collagen to re-absorb water is reduced. Our results are important for revealing the presence of bound H2 O within the collagen component of connective tissue even after freeze-drying and its role in denaturation that is accompanied by or perhaps preceded by breakdown of the primary polypeptide structure. © 2017 Wiley Periodicals, Inc.

  18. Effects of phototherapy on cartilage structure and inflammatory markers in an experimental model of osteoarthritis (United States)

    Oliveira, Poliani; Santos, Anderson Amaro; Rodrigues, Tamara; Tim, Carla Roberta; Pinto, Karina Zambone; Magri, Angela Maria Paiva; Fernandes, Kelly Rossetti; Mattiello, Stela M.; Parizotto, Nivaldo Antonio; Anibal, Fernanda Freitas; Rennó, Ana Claudia Muniz


    The aim of this study was to evaluate the effects of laser phototherapy on the degenerative modifications on the articular cartilage after the anterior cruciate ligament transection (ACLT) in the knee of rats. Eighty male rats (Wistar) were distributed into four groups: intact control group (IG), injured control group (CG), injured laser treated group at 10 J/cm2 (L10), and injured laser treated group at 50 J/cm2 (L50). Animals were distributed into two subgroups, sacrificed in 5 and 8 weeks postsurgery. The ACLT was used to induce knee osteoarthritis in rats. After 2 weeks postsurgery, laser phototherapy initiated and it was performed for 15 and 30 sessions. The histological findings revealed that laser irradiation, especially at 10 J/cm2, modulated the progression of the degenerative process, showing a better cartilage structure and lower number of condrocytes compared to the other groups. Laser phototherapy was not able to decrease the degenerative process measured by Mankin score and prevent the increase of cartilage thickness related to the degenerative process. Moreover, it did not have any effect in the biomodulation of the expression of markers IL1β, tumor necrosis factor-α, and metalloprotein-13. Furthermore, laser irradiated animals, at 50 J/cm2 showed a lower amount of collagen type 1.

  19. The C-terminal domain of connexin43 modulates cartilage structure via chondrocyte phenotypic changes. (United States)

    Gago-Fuentes, Raquel; Bechberger, John F; Varela-Eirin, Marta; Varela-Vazquez, Adrian; Acea, Benigno; Fonseca, Eduardo; Naus, Christian C; Mayan, Maria D


    Chondrocytes in cartilage and bone cells population express connexin43 (Cx43) and gap junction intercellular communication (GJIC) is essential to synchronize cells for coordinated electrical, mechanical, metabolic and chemical communication in both tissues. Reduced Cx43 connectivity decreases chondrocyte differentiation and defective Cx43 causes skeletal defects. The carboxy terminal domain (CTD) of Cx43 is located in the cytoplasmic side and is key for protein functions. Here we demonstrated that chondrocytes from the CTD-deficient mice, K258stop/Cx43KO and K258stop/K258stop, have reduced GJIC, increased rates of proliferation and reduced expression of collagen type II and proteoglycans. We observed that CTD-truncated mice were significantly smaller in size. Together these results demonstrated that the deletion of the CTD negatively impacts cartilage structure and normal chondrocyte phenotype. These findings suggest that the proteolytic cleavage of the CTD under pathological conditions, such as under the activation of metalloproteinases during tissue injury or inflammation, may account for the deleterious effects of Cx43 in cartilage and bone disorders such as osteoarthritis.

  20. Engineering superficial zone features in tissue engineered cartilage. (United States)

    Chen, Tony; Hilton, Matthew J; Brown, Edward B; Zuscik, Michael J; Awad, Hani A


    A major challenge in cartilage tissue engineering is the need to recreate the native tissue's anisotropic extracellular matrix structure. This anisotropy has important mechanical and biological consequences and could be crucial for integrative repair. Here, we report that hydrodynamic conditions that mimic the motion-induced flow fields in between the articular surfaces in the synovial joint induce the formation of a distinct superficial layer in tissue engineered cartilage hydrogels, with enhanced production of cartilage matrix proteoglycan and Type II collagen. Moreover, the flow stimulation at the surface induces the production of the surface zone protein Proteoglycan 4 (aka PRG4 or lubricin). Analysis of second harmonic generation signature of collagen in this superficial layer reveals a highly aligned fibrillar matrix that resembles the alignment pattern in native tissue's surface zone, suggesting that mimicking synovial fluid flow at the cartilage surface in hydrodynamic bioreactors could be key to creating engineered cartilage with superficial zone features. Copyright © 2012 Wiley Periodicals, Inc.

  1. Evaluation of influence of proteoglycans on hydration of articular cartilage with the use of ultrasound

    Directory of Open Access Journals (Sweden)

    Yi-yi YANG


    Full Text Available Objective To monitor the changes in hydration behaviour of articular cartilage induced by degradation of proteoglycans, and to explore the effect of proteoglycans on hydration behaviour of articular cartilage by using high-frequency ultrasound. Methods Twelve porcine patellae with smooth cartilage surface were prepared and equally divided into two groups: normal group without any enzyme treatment, and trypsin group they were treated with 0.25% trypsin for 8h to digest proteoglycan in the cartilage. The hydration behaviour of the cartilage tissue was scanned by high-frequency ultrasound system with a central frequency of 25MHz. Parameters including cartilage hydration strain and cartilage thickness were measured. The histopathological changes in the articular cartilage were observed under a light microscope. Results It took approximately 20min to reach equilibrium during the hydration process in the normal cartilages, while proteoglycan-degraded cartilage took only about 5min to achieve equilibrium. The equilibrium strain of normal cartilage was 3.5%±0.5%. The degradation of proteoglycans induced a significant decrease in equilibrium strain (1.8%±0.2%, P0.05. Conclusion Proteoglycans play an important role in hydration behaviour of articular cartilage. The degradation of proteoglycans could induce degeneration of cartilage structure and decrease in hydration behaviour after dehydration. DOI: 10.11855/j.issn.0577-7402.2015.03.03

  2. Boundary conditions for cartilage regeneration

    NARCIS (Netherlands)

    Auw Yang, K.G.


    Cartilage defects generally do not heal and may result in osteoarthritis (OA) development. Unfortunately, current treatment strategies result in repair tissue with insufficient structural and mechanical properties as compared to native cartilage, and, therefore, are thought to provide merely a

  3. Clinical significance of cartilage biomarkers for monitoring structural joint damage in rheumatoid arthritis patients treated with anti-TNF therapy. (United States)

    Niki, Yasuo; Takeuchi, Tsutomu; Nakayama, Masanori; Nagasawa, Hayato; Kurasawa, Takahiko; Yamada, Harumoto; Toyama, Yoshiaki; Miyamoto, Takeshi


    With the current use of biologics in rheumatoid arthritis (RA), there is a need to monitor ongoing structural joint damage due to the dissociation of articular cartilage damage from disease activity of RA. This study longitudinally analyzed levels of serum cartilage biomarkers during 54 weeks of infliximab therapy, to evaluate the feasibility of biomarkers for monitoring structural joint damage. Subjects comprised 33 patients with early RA and 33 patients with established RA. All patients received 3 mg/kg of infliximab and methotrexate for 54 weeks. Levels of the following serum cartilage markers were measured at baseline and at weeks 14, 22, and 54: hyaluronan (HA); cartilage oligometric matrix protein (COMP); type II collagen (CII)-related neoepitope (C2C); type II procollagen carboxy-propeptide (CPII); and keratin sulfate (KS). Time courses for each biomarker were assessed, and relationships between these biomarkers and clinical or radiographic parameters generally used for RA were investigated. Levels of CRP, MMP-3, DAS28-CRP, and annual progression of TSS were improved to similar degrees in both groups at week 54. HA and C2C/CPII were significantly decreased compared to baseline in the early RA group (pstructural joint damage with the least association with CRP, and that irreversible cartilage damage in established RA limits restoration of the C2C/CPII level, even with tight control of joint inflammation. The temporal course of C2C/CPII level during anti-TNF therapy indicates that CII turnover shifts toward CII synthesis in early RA, but not in established RA, potentially due to irreversible cartilage damage. ΔC2C/CPII appears to offer a useful marker reflecting ongoing structural joint damage, dissociated from inflammatory indices such as CRP and MMP-3.


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    Full Text Available INTRODUCTION: A variety of organic and inorganic materials is used as grafts in Ossiculoplasty and reconstruction of the outer attic wall and posterior wall of External Auditory Meatus. Tragal cartilage, Conchal cartilage and septal cartilages are frequently used as auto grafts during Tympanoplasty surgery for reconstruction of Ossicular chain. Cartilage grafts used for Ossicular replacement should be thick, sturdy, easily sculpted and without much elasticity. If the graft has elastic nature it tends to reduce the conduction of sound vibrations. Auricular cartilage is accessible through the same post aural incision used for the mastoid surgery. If the auricular cartilage is palpated for the thickness, one would find that the thickest part is the isthmus. It is felt below and posterior to the inter tragal sulcus. The present study is to measure the thickness of the isthmus part of the auricle cartilage. It also includes study of histology of the cartilage of isthmus to observe the stacks of cells present between the two layers of the perichondrium. MATERIALS AND METHODS: The cartilage of isthmus from 36 cadavers is dissected to measure its thickness and for histology study. Cartilage of isthmus from 36 patients undergoing Modified Radical Mastoidectomy is measured for their thickness and histology is studied. A sterile steel calipers is used to measure the thickness of the cartilage, after exposing the cartilage from posterior aspect during surgery. The tips of the calipers are kept touching the perichondrium on both sides. Thin histology sections are taken after embedding the cartilage in paraffin moulds. Hematoxyline and Eosin stain is used to study the histology. The thickest portion of the cartilage is sculpted to be used as a strut in Type III Tympanoplasty. OBSERVATIONS: The thickness of the cartilage varied from 2.1 to 3mm. The number of stacks of chondrocytes varied from 5 to 7. The physical nature of the cartilage is sturdy and easily

  5. Laser-induced micropore formation and modification of cartilage structure in osteoarthritis healing

    Energy Technology Data Exchange (ETDEWEB)

    Sobol, Emil [Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod, RussiabFederal Scientific Research Centre “Crystallography and Photonics” of the Russian Academy of Sciences, Institute of Photonic Technologies, Moscow, Russia; Baum, Olga [Federal Scientific Research Centre “Crystallography and Photonics” of the Russian Academy of Sciences, Institute of Photonic Technologies, Moscow, Russia; Shekhter, Anatoly [Sechenov First Medical University of Moscow, Institute of Regenerative Medicine, Moscow, Russia; Wachsmann-Hogiu, Sebastian [University of California, Center for Biophotonics, Department of Pathology and Laboratory Medicine, Sacramento, California, United StateseMcGill University, Department of Bioengineering, Montreal, Canada; Shnirelman, Alexander [Concordia University, Department of Mathematics and Statistics, Montreal, Canada; Alexandrovskaya, Yulia [Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod, RussiabFederal Scientific Research Centre “Crystallography and Photonics” of the Russian Academy of Sciences, Institute of Photonic Technologies, Moscow, Russia; Sadovskyy, Ivan [Argonne National Laboratory, Materials Science Division, Argonne, Illinois, United States; Vinokur, Valerii [Argonne National Laboratory, Materials Science Division, Argonne, Illinois, United States


    Pores are vital for functioning of avascular tissues. Laser-induced pores play an important role in the process of cartilage regeneration. The aim of any treatment for osteoarthritis is to repair hyaline-type cartilage. The aims of this study are to answer two questions: (1) How do laser-assisted pores affect the cartilaginous cells to synthesize hyaline cartilage (HC)? and (2) How can the size distribution of pores arising in the course of laser radiation be controlled? We have shown that in cartilage, the pores arise predominately near chondrocytes, which promote nutrition of cells and signal molecular transfer that activates regeneration of cartilage. In vivo laser treatment of damaged cartilage of miniature pig joints provides cellular transformation and formation of HC. We propose a simple model of pore formation in biopolymers that paves the way for going beyond the trial-anderror approach when choosing an optimal laser treatment regime. Our findings support the approach toward laser healing of osteoarthritis.

  6. Automated hexahedral meshing of knee cartilage structures - application to data from the osteoarthritis initiative. (United States)

    Rodriguez-Vila, B; Sánchez-González, P; Oropesa, I; Gomez, E J; Pierce, D M


    We propose a fully automated methodology for hexahedral meshing of patient-specific structures of the human knee obtained from magnetic resonance images, i.e. femoral/tibial cartilages and menisci. We select eight patients from the Osteoarthritis Initiative and validate our methodology using MATLAB on a laptop computer. We obtain the patient-specific meshes in an average of three minutes, while faithfully representing the geometries with well-shaped elements. We hope to provide a fundamentally different means to test hypotheses on the mechanisms of disease progression by integrating our patient-specific FE meshes with data from individual patients. Download both our meshes and software at .

  7. [Therapeutic algorithm for traumatic cartilage injuries]. (United States)

    Miltner, Oliver; Hagemann, Lars; Ristan, Steven; Siebert, Christian H


    Reports regarding sport injuries frequently pertain to the knee. Although ligament and meniscus damage are the most common, cartilage injuries are of great interest. Even with the great variety of treatment modalities available, the healing of these cartilage injuries remains problematic. Due to the complex structure of hyaline cartilage joint surface, repair has proven to be very difficult. The conservative treatment options range from orthotic devices and physical therapy to systemic and intraarticular medication. In case of failure, a wide variety of surgical interventions exist. Among these surgical treatment forms, one must differentiate between the repair and the reconstruction of hyaline joint surfaces. In the latter group only the osteochondral autologous transplantation procedures allow for the reconstruction of a cartilaginous lesion with hyaline cartilage as part of a single procedure. This paper will provide an overview of most common therapeutic approaches to cartilage injuries available today. Even with the ongoing discussions with regard to cartilage healing, the basics such as the ligamentous stability of the affected joint, the mechanical axis of the extremity and good neuromuscular control must always be part of the algorithm.

  8. Swelling and curling behaviors of articular cartilage. (United States)

    Setton, L A; Tohyama, H; Mow, V C


    A new experimental method was developed to quantify parameters of swelling-induced shape change in articular cartilage. Full-thickness strips of cartilage were studied in free-swelling tests and the swelling-induced stretch, curvature, and areal change were measured. In general, swelling-induced stretch and curvature were found to increase in cartilage with decreasing ion concentration, reflecting an increasing tendency to swell and "curl" at higher swelling pressures. An exception was observed at the articular surface, which was inextensible for all ionic conditions. The swelling-induced residual strain at physiological ionic conditions was estimated from the swelling-induced stretch and found to be tensile and from 3-15 percent. Parameters of swelling were found to vary with sample orientation, reflecting a role for matrix anisotropy in controlling the swelling-induced residual strains. In addition, the surface zone was found to be a structurally important element, which greatly limits swelling of the entire cartilage layer. The findings of this study provide the first quantitative measures of swelling-induced residual strain in cartilage ex situ, and may be readily adapted to studies of cartilage swelling in situ.

  9. Unique Biology of Shoulder Cartilage in Comparison to the Cartilage Obtained from the Knee and Ankle Joints (United States)

    Chubinskaya, Susan; Meyer, Maximilian A.; Urita, Atsushi; Verma, Nikhil N.; Romeo, Anthony A.; Yanke, Adam Blair; Cole, Brian J.


    Objectives: Glenohumeral joint (GHJ) arthritis in relatively young active patients presents a considerable clinical challenge. Little is known regarding the biology and reparative capacity of GHJ articular cartilage and how it compares to other diarthrodial joints. The objectives of the current study were to 1) describe the histological and morphological appearance of human normal GHJ cartilage; and 2) investigate cellular responses of GHJ cartilage to interleukin-1β (IL-1β), in comparison to cartilage obtained from the knee and ankle of the same donors. Methods: GHJ, knee (femoral condyle) and ankle (talus) cartilage was obtained through the Gift of Hope Organ and Tissue Donor Network (Itasca, IL) from nine human donors with no documented history of joint diseases (58-75 yo, both genders). Gross morphology of each joint was assessed using Collins grading on a scale 0 to 4. Cartilage explants (3 mm diameter) were removed from each joint, cultured for 48 hours with or without interleukin-1β (IL-1β; 0.1ng/ml or 10ng/ml), and processed for histology with Safranin O, proteoglycan (PG) synthesis/content, and PCR for key extracellular matrix (ECM) genes: Col2, Agg, and SOX9. Results were compared between uncultured and cultured controls and across all three included joints. Results: Unlike grossly normal (Collins grades 0-1) knee and ankle cartilage, grossly normal GHJ cartilage with an intact surface displayed signs of subtle structural changes: loss of Safranin O in the upper layer and in the ECM and increased staining around chondrocytes suggesting elevated metabolic activity. Differences became more apparent with higher Collins grades or in the presence of IL-1β. Treatment with IL-1β (both doses) resulted in more than 2-fold inhibition of PG synthesis in GHJ cartilage (p<0.05), while only high dose IL-1β had the same effect on the knee or ankle cartilage. At the control level, expression of Col2 and Sox9 was comparable between all types of cartilages; Agg

  10. Regional dGEMRIC analysis in patients at risk of osteoarthritis provides additional information about activity related changes in cartilage structure

    DEFF Research Database (Denmark)

    Hawezi, Z K; Lammentausta, E; Svensson, J


    . PURPOSE: To improve the knowledge about exercise effects on cartilage structure by re-analyzing previous images with regional dGEMRIC analysis. MATERIAL AND METHODS: Thirty patients (age range, 38-50 years) with a previous medial meniscus resection were divided into three groups according to self......BACKGROUND: Previously, a positive effect of exercise on cartilage structure was indicated with delayed gadolinium-enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC). However, in that study only one full-thickness region of interest (ROI) in the medial femoral condyle was analyzed...... load) ROIs of medial and lateral femoral condyles were analyzed, as well as superficial and deep cartilage regions. RESULTS: Group I increased the dGEMRIC index in the posterior cartilage (P = 0.004). The increase was larger in the lateral (P = 0.005) than the medial compartment in both superficial...

  11. Mechanical properties and structure-function relationships of human chondrocyte-seeded cartilage constructs after in vitro culture. (United States)

    Middendorf, Jill M; Griffin, Darvin J; Shortkroff, Sonya; Dugopolski, Caroline; Kennedy, Stephen; Siemiatkoski, Joseph; Cohen, Itai; Bonassar, Lawrence J


    Autologous Chondrocyte Implantation (ACI) is a widely recognized method for the repair of focal cartilage defects. Despite the accepted use, problems with this technique still exist, including graft hypertrophy, damage to surrounding tissue by sutures, uneven cell distribution, and delamination. Modified ACI techniques overcome these challenges by seeding autologous chondrocytes onto a 3D scaffold and securing the graft into the defect. Many studies on these tissue engineered grafts have identified the compressive properties, but few have examined frictional and shear properties as suggested by FDA guidance. This study is the first to perform three mechanical tests (compressive, frictional, and shear) on human tissue engineered cartilage. The objective was to understand the complex mechanical behavior, function, and changes that occur with time in these constructs grown in vitro using compression, friction, and shear tests. Safranin-O histology and a DMMB assay both revealed increased sulfated glycosaminoglycan (sGAG) content in the scaffolds with increased maturity. Similarly, immunohistochemistry revealed increased lubricin localization on the construct surface. Confined compression and friction tests both revealed improved properties with increased construct maturity. Compressive properties correlated with the sGAG content, while improved friction coefficients were attributed to increased lubricin localization on the construct surfaces. In contrast, shear properties did not improve with increased culture time. This study suggests the various mechanical and biological properties of tissue engineered cartilage improve at different rates, indicating thorough mechanical evaluation of tissue engineered cartilage is critical to understanding the performance of repaired cartilage. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2298-2306, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  12. Engineering Cartilage (United States)

    ... Research Matters NIH Research Matters March 3, 2014 Engineering Cartilage Artistic rendering of human stem cells on ... situations has been a major goal in tissue engineering. Cartilage contains water, collagen, proteoglycans, and chondrocytes. Collagens ...

  13. Collagen Scaffolds with Controlled Insulin Release and Controlled Pore Structure for Cartilage Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Himansu Sekhar Nanda


    Full Text Available Controlled and local release of growth factors and nutrients from porous scaffolds is important for maintenance of cell survival, proliferation, and promotion of tissue regeneration. The purpose of the present research was to design a controlled release porous collagen-microbead hybrid scaffold with controlled pore structure capable of releasing insulin for application to cartilage tissue regeneration. Collagen-microbead hybrid scaffold was prepared by hybridization of insulin loaded PLGA microbeads with collagen using a freeze-drying technique. The pore structure of the hybrid scaffold was controlled by using preprepared ice particulates having a diameter range of 150–250 μm. Hybrid scaffold had a controlled pore structure with pore size equivalent to ice particulates and good interconnection. The microbeads showed an even spatial distribution throughout the pore walls. In vitro insulin release profile from the hybrid scaffold exhibited a zero order release kinetics up to a period of 4 weeks without initial burst release. Culture of bovine articular chondrocytes in the hybrid scaffold demonstrated high bioactivity of the released insulin. The hybrid scaffold facilitated cell seeding and spatial cell distribution and promoted cell proliferation.

  14. Cartilage imaging in sports medicine. (United States)

    Black, Brandon R; Chong, Le Roy; Potter, Hollis G


    Magnetic resonance imaging (MRI) using cartilage-sensitive sequences has been shown to be an accurate, noninvasive method by which to detect articular cartilage injury and early degeneration. These are important management considerations in an athletic population. The advantages of MRI include the lack of ionizing radiation, direct multiplanar capabilities and high-contrast resolution of articular soft tissue structures. The present review details imaging strategies for assessing cartilage in the athletic population, defines the normal MRI appearance of articular cartilage, and illustrates the spectrum of articular cartilage lesions seen in various joints of the body.

  15. Evaluation of structural and mechanical properties of electrospun nano-micro hybrid of poly hydroxybutyrate-chitosan/silk scaffold for cartilage tissue engineering. (United States)

    Karbasi, Saeed; Fekrat, Farnoosh; Semnani, Daryoush; Razavi, Shahnaz; Zargar, Elham Naghash


    One of the new methods of scaffold fabrication is a nano-micro hybrid structure in which the properties of the scaffold are improved by introducing nanometer and micrometer structures. This method could be suitable for scaffold designing if some features improve. In this study, electrospun nanofibers of 9% weight solution of poly (3-hydroxybutyrate) (P3HB) and a 15% weight of chitosan by trifluoroacetic acid were coated on both the surface of a silk knitted substrate in the optimum condition to improve the mechanical properties of scaffolds for cartilage tissue engineering application. These hybrid nano-micro fibrous scaffolds were characterized by structural and mechanical evaluation methods. Scanning electron microscopy values and porosity analysis showed that average diameter of nanofibers was 584.94 nm in electrospinning part and general porosity was more than 80%. Fourier transform infrared spectroscopy results indicated the presence of all elements without pollution. The tensile test also stated that by electrospinning, as well as adding chitosan, both maximum strength and maximum elongation increased to 187 N and 10 mm. It means that the microfibrous part of scaffold could affect mechanical properties of nano part of the hybrid scaffold, significantly. It could be concluded that P3HB-chitosan/silk hybrid scaffolds can be a good candidate for cartilage tissue engineering.

  16. Laser-induced micropore formation and modification of cartilage structure in osteoarthritis healing (United States)

    Sobol, Emil; Baum, Olga; Shekhter, Anatoly; Wachsmann-Hogiu, Sebastian; Shnirelman, Alexander; Alexandrovskaya, Yulia; Sadovskyy, Ivan; Vinokur, Valerii


    Pores are vital for functioning of avascular tissues. Laser-induced pores play an important role in the process of cartilage regeneration. The aim of any treatment for osteoarthritis is to repair hyaline-type cartilage. The aims of this study are to answer two questions: (1) How do laser-assisted pores affect the cartilaginous cells to synthesize hyaline cartilage (HC)? and (2) How can the size distribution of pores arising in the course of laser radiation be controlled? We have shown that in cartilage, the pores arise predominately near chondrocytes, which promote nutrition of cells and signal molecular transfer that activates regeneration of cartilage. In vivo laser treatment of damaged cartilage of miniature pig joints provides cellular transformation and formation of HC. We propose a simple model of pore formation in biopolymers that paves the way for going beyond the trial-and-error approach when choosing an optimal laser treatment regime. Our findings support the approach toward laser healing of osteoarthritis.

  17. Laser-structured bacterial nanocellulose hydrogels support ingrowth and differentiation of chondrocytes and show potential as cartilage implants. (United States)

    Ahrem, Hannes; Pretzel, David; Endres, Michaela; Conrad, Daniel; Courseau, Julien; Müller, Hartmut; Jaeger, Raimund; Kaps, Christian; Klemm, Dieter O; Kinne, Raimund W


    The small size and heterogeneity of the pores in bacterial nanocellulose (BNC) hydrogels limit the ingrowth of cells and their use as tissue-engineered implant materials. The use of placeholders during BNC biosynthesis or post-processing steps such as (touch-free) laser perforation can overcome this limitation. Since three-dimensionally arranged channels may be required for homogeneous and functional seeding, three-dimensional (3-D) laser perforation of never-dried BNC hydrogels was performed. Never-dried BNC hydrogels were produced in different shapes by: (i) the cultivation of Gluconacetobacter xylinus (DSM 14666; synonym Komagataeibacter xylinus) in nutrient medium; (ii) the removal of bacterial residues/media components (0.1M NaOH; 30 min; 100 °C) and repeated washing (deionized water; pH 5.8); (iii) the unidirectional or 3-D laser perforation and cutting (pulsed CO2 Rofin SC × 10 laser; 220 μm channel diameter); and (iv) the final autoclaving (2M NaOH; 121 °C; 20 min) and washing (pyrogen-free water). In comparison to unmodified BNC, unidirectionally perforated--and particularly 3-D-perforated - BNC allowed ingrowth into and movement of vital bovine/human chondrocytes throughout the BNC nanofiber network. Laser perforation caused limited structural modifications (i.e. fiber or globular aggregates), but no chemical modifications, as indicated by Fourier transform infrared spectroscopy, X-ray photoelectron scattering and viability tests. Pre-cultured human chondrocytes seeding the surface/channels of laser-perforated BNC expressed cartilage-specific matrix products, indicating chondrocyte differentiation. 3-D-perforated BNC showed compressive strength comparable to that of unmodified samples. Unidirectionally or 3-D-perforated BNC shows high biocompatibility and provides short diffusion distances for nutrients and extracellular matrix components. Also, the resulting channels support migration into the BNC, matrix production and phenotypic stabilization of

  18. Laser-induced modification of structure and shape of cartilage in otolaryngology and orthopaedics (United States)

    Sobol’, E. N.; Baum, O. I.; Omel’chenko, A. I.; Soshnikova, Yu. M.; Yuzhakov, A. V.; Kas’yanenko, E. M.; Tokareva, A. V.; Baskov, A. V.; Svistushkin, V. M.; Selezneva, L. V.; Shekhter, A. B.


    We present the results of basic research in laser modification of tissues in otolaryngology (correcting the shape of nasal septum and larynx cartilages), cosmetology (correcting ear and nose shape), orthopaedics and spinal surgery (treatment of diseases of spine disc and joints). The physical processes and mechanisms of laser-induced relaxation of stresses and regeneration of tissues are considered. New results of studies in this fast-developing field of laser surgery are presented, in particular, the results of laser correction of costal cartilage shape in the process of making implants for the treatment of larynx stenosis and controlled regeneration of the hyaline articular cartilage. Presented at the Fundamentals of Laser Assisted Micro- and Nanotechnologies (FLAMN-2016) International Symposium (Pushkin, Leningrad oblast, 27 June to 1 July 2016).

  19. Research trends in biomimetic medical materials for tissue engineering: 3D bioprinting, surface modification, nano/micro-technology and clinical aspects in tissue engineering of cartilage and bone. (United States)

    Chen, Cen; Bang, Sumi; Cho, Younghak; Lee, Sahnghoon; Lee, Inseop; Zhang, ShengMin; Noh, Insup


    This review discusses about biomimetic medical materials for tissue engineering of bone and cartilage, after previous scientific commentary of the invitation-based, Korea-China joint symposium on biomimetic medical materials, which was held in Seoul, Korea, from October 22 to 26, 2015. The contents of this review were evolved from the presentations of that symposium. Four topics of biomimetic medical materials were discussed from different research groups here: 1) 3D bioprinting medical materials, 2) nano/micro-technology, 3) surface modification of biomaterials for their interactions with cells and 4) clinical aspects of biomaterials for cartilage focusing on cells, scaffolds and cytokines.

  20. Zn deposition at the bone-cartilage interface in equine articular cartilage

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, D.A. [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom)], E-mail:; Moger, C.J.; Winlove, C.P. [School of Physics, University of Exeter, Exeter, EX4 4QL (United Kingdom)


    In articular cartilage metalloproteinases, a family of enzymes whose function relies on the presence of divalent cations such as Zn and Ca plays a central role in the normal processes of growth and remodelling and in the degenerative and inflammatory processes of arthritis. Another important enzyme, alkaline phosphatase, involved in cartilage mineralisation also relies on metallic cofactors. The local concentration of divalent cations is therefore of considerable interest in cartilage pathophysiology and several authors have used synchrotron X-ray fluorescence (XRF) to map metal ion distributions in bone and cartilage. We report use of a bench-top XRF analytical microscope, providing spatial resolution of 10 {mu}m and applicable to histological sections, facilitating correlation of the distribution with structural features. The study seeks to establish the elemental distribution in normal tissue as a precursor to investigation of changes in disease. For six samples prepared from equine metacarpophalangeal joint, we observed increased concentration of Zn and Sr ions around the tidemark between normal and mineralised cartilage. This is believed to be an active site of remodelling but its composition has hitherto lacked detailed characterization. We also report preliminary results on two of the samples using Proton-Induced X-ray Emission (PIXE). This confirms our previous observations using synchrotron-based XRF of enhanced deposition of Sr and Zn at the surface of the subchondral bone and in articular cartilage.

  1. Cartilage tissue engineering on the surface of a novel gelatin-calcium-phosphate biphasic scaffold in a double-chamber bioreactor. (United States)

    Chang, Chih-Hung; Lin, Feng-Huei; Lin, Chien-Cheng; Chou, Cheng-Hung; Liu, Hwa-Chang


    Tissue engineering is a new approach to articular cartilage repair; however, the integration of the engineered cartilage into the host subchondral bone is a major problem in osteochondral injury. The aim of the present work, therefore, was to make a tissue-engineered osteochondral construct from a novel biphasic scaffold in a newly designed double-chamber bioreactor. This bioreactor was designed to coculture chondrocytes and osteoblasts simultaneously. The aim of this study was to prove that engineered cartilage could be formed with the use of this biphasic scaffold. The scaffold was constructed from gelatin and a calcium-phosphate block made from calcined bovine bone. The cartilage part of the scaffold had a uniform pore size of about 180 microm and approximate porosity of 75%, with the trabecular pattern preserved in the bony part of the scaffold. The biphasic scaffolds were seeded with porcine chondrocytes and cultured in a double-chamber bioreactor for 2 or 4 weeks. The chondrocytes were homogeneously distributed in the gelatin part of the scaffold, and secretion of the extracellular matrix was demonstrated histologically. The chondrocytes retained their phenotype after 4 weeks of culture, as proven immunohistochemically. After 4 weeks of culture, hyaline-like cartilage with lacuna formation could be clearly seen in the gelatin scaffold on the surface of the calcium phosphate. The results show that this biphasic scaffold can support cartilage formation on a calcium-phosphate surface in a double-chamber bioreactor, and it seems reasonable to suggest that there is potential for further application in osteochondral tissue engineering. (c) 2004 Wiley Periodicals, Inc.

  2. Effects of antiinflammatory drugs on arthritic cartilage: a high-frequency quantitative ultrasound study in rats. (United States)

    Jaffré, Britta; Watrin, Astrid; Loeuille, Damien; Gillet, Pierre; Netter, Patrick; Laugier, Pascal; Saïed, Amena


    To evaluate the ability of 55-MHz quantitative ultrasound (US) to detect the in vivo effects of experimental arthritis, as well as those of two antiinflammatory drugs, naproxen (NPX) and dexamethasone (DEX), on cartilage and subchondral bone. Arthritis was induced in both knees of 108 rats by intraarticular injection of zymosan (ZYM). Two groups of arthritic rats (n = 36 per group) were treated daily with either NPX (10 mg/kg/day) or DEX (0.1 mg/kg/day). Using a 3-dimensional US microscope, patellae were explored in vitro on days 5, 14, and 21 after injections. US assessment included the analysis of quantitative indices of local modifications involving cartilage and bone: integrated reflection coefficient (IRC) from the cartilage surface and apparent integrated backscatter from the cartilage internal structure (cartilage matrix) (AIB(cartilage)) and the cartilage-bone interface (AIB(bone)). ZYM induced articular surface fibrillation that resulted in a decrease in IRC at all times (P < 0.02) and in an increase in AIB(bone) on days 5 and 14 (P < 0.005). Fibrillation was not changed by NPX administration, while it disappeared following DEX treatment. Cartilage-bone interface alterations were prevented by DEX and partially compensated for by NPX. Cartilage matrix echogenicity decreased with time in all groups due to maturation (P < 0.05), except in DEX-treated rats. Quantitative 55 MHz US allowed detection of early cartilage and bone lesions due to experimental arthritis, and also allowed detection of the effects of antiinflammatory drugs. NPX seemed to have an effect on subchondral bone lesions, but not on cartilage. DEX appeared to repair articular surface and bone, but prevented animal growth and cartilage maturation.


    African Journals Online (AJOL)

    1: Tilting table apparatus for the determination of friction coefficient. The friction surface with the cylinder resting on was gradually lifted (inclined) with the bolt and nut-arrangement until the cylinder, along with the sample just began to slide down. At this point, the bolt adjustment was stopped and the. ' angle which was made ...

  4. Microstructural and compositional features of the fibrous and hyaline cartilage on the medial tibial plateau imply a unique role for the hopping locomotion of kangaroo. (United States)

    He, Bo; Wu, Jian Ping; Xu, Jiake; Day, Robert E; Kirk, Thomas Brett


    Hopping provides efficient and energy saving locomotion for kangaroos, but it results in great forces in the knee joints. A previous study has suggested that a unique fibrous cartilage in the central region of the tibial cartilage could serve to decrease the peak stresses generated within kangaroo tibiofemoral joints. However, the influences of the microstructure, composition and mechanical properties of the central fibrous and peripheral hyaline cartilage on the function of the knee joints are still to be defined. The present study showed that the fibrous cartilage was thicker and had a lower chondrocyte density than the hyaline cartilage. Despite having a higher PG content in the middle and deep zones, the fibrous cartilage had an inferior compressive strength compared to the peripheral hyaline cartilage. The fibrous cartilage had a complex three dimensional collagen meshwork with collagen bundles parallel to the surface in the superficial zone, and with collagen bundles both parallel and perpendicular to the surface in the middle and deep zones. The collagen in the hyaline cartilage displayed a typical Benninghoff structure, with collagen fibres parallel to the surface in the superficial zone and collagen fibres perpendicular to the surface in the deep zone. Elastin fibres were found throughout the entire tissue depth of the fibrous cartilage and displayed a similar alignment to the adjacent collagen bundles. In comparison, the elastin fibres in the hyaline cartilage were confined within the superficial zone. This study examined for the first time the fibrillary structure, PG content and compressive properties of the central fibrous cartilage pad and peripheral hyaline cartilage within the kangaroo medial tibial plateau. It provided insights into the microstructure and composition of the fibrous and peripheral hyaline cartilage in relation to the unique mechanical properties of the tissues to provide for the normal activities of kangaroos.

  5. Microstructural and compositional features of the fibrous and hyaline cartilage on the medial tibial plateau imply a unique role for the hopping locomotion of kangaroo.

    Directory of Open Access Journals (Sweden)

    Bo He

    Full Text Available Hopping provides efficient and energy saving locomotion for kangaroos, but it results in great forces in the knee joints. A previous study has suggested that a unique fibrous cartilage in the central region of the tibial cartilage could serve to decrease the peak stresses generated within kangaroo tibiofemoral joints. However, the influences of the microstructure, composition and mechanical properties of the central fibrous and peripheral hyaline cartilage on the function of the knee joints are still to be defined. The present study showed that the fibrous cartilage was thicker and had a lower chondrocyte density than the hyaline cartilage. Despite having a higher PG content in the middle and deep zones, the fibrous cartilage had an inferior compressive strength compared to the peripheral hyaline cartilage. The fibrous cartilage had a complex three dimensional collagen meshwork with collagen bundles parallel to the surface in the superficial zone, and with collagen bundles both parallel and perpendicular to the surface in the middle and deep zones. The collagen in the hyaline cartilage displayed a typical Benninghoff structure, with collagen fibres parallel to the surface in the superficial zone and collagen fibres perpendicular to the surface in the deep zone. Elastin fibres were found throughout the entire tissue depth of the fibrous cartilage and displayed a similar alignment to the adjacent collagen bundles. In comparison, the elastin fibres in the hyaline cartilage were confined within the superficial zone. This study examined for the first time the fibrillary structure, PG content and compressive properties of the central fibrous cartilage pad and peripheral hyaline cartilage within the kangaroo medial tibial plateau. It provided insights into the microstructure and composition of the fibrous and peripheral hyaline cartilage in relation to the unique mechanical properties of the tissues to provide for the normal activities of kangaroos.

  6. Joint degeneration following meniscal allograft transplantation in a canine model: mechanical properties and semiquantitative histology of articular cartilage. (United States)

    Elliott, Dawn M; Jones, Relief; Setton, Lori A; Scully, Sean P; Vail, T Parker; Guilak, Farshid


    This study examined the hypothesis that meniscal allograft transplantation serves a "chondroprotective" role and prevents the histological and biomechanical changes of the articular cartilage following meniscectomy. Skeletally mature mongrel dogs underwent total medial meniscectomy and received either a fresh meniscal allograft ( n=10) or no further treatment ( n=10). Semiquantitative histology and biomechanical analysis of the femoral articular cartilage was used to assess cartilage pathology 12 weeks following surgery. Histological analysis showed significant changes in cartilage structure that did not differ between the meniscectomy and allograft transplantation groups. Similarly, the tensile modulus of the surface zone cartilage was significantly lower than that in unoperated controls following either meniscectomy or allograft transplantation. A significant correlation was observed between the biomechanical and histological changes, suggesting that degenerative changes in cartilage structure and mechanical function are interrelated. Our findings do not support the hypothesis that meniscal allograft transplantation provides chondroprotection of the femoral condyle and also suggest that it does not lead to increased degenerative changes.

  7. Fabrication and characterization of a novel microparticle with gyrus-patterned surface and growth factor delivery for cartilage tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Huang Sha [Department of Oral Histology and Pathology, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi' an 710032 (China); Wang Yijuan [Key Laboratory for Macromolecular Science of Shaanxi Province, Shaanxi Normal University, Xi' an 710062 (China); Liang Tang [Department of Oral Histology and Pathology, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi' an 710032 (China); Jin Fang [Department of Orthodontics, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Liu Shouxin [Key Laboratory for Macromolecular Science of Shaanxi Province, Shaanxi Normal University, Xi' an 710062 (China); Jin Yan, E-mail: [Department of Oral Histology and Pathology, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi' an 710032 (China)


    Microparticles can serve as substrates for cell amplification and deliver the expanded cells to the site of the defect. It was hypothesized that a novel microparticle combined of sustained and localized delivery of proliferative growth factors and gyrus-patterned surface would influence the cell behaviours of adherence and expansion on the microparticle in the present study. To test the hypothesis, gelatin particles with diameter ranging from 280 to 350 {mu}m were fabricated and were modified by cryogenic freeze-drying treatment and basic fibroblast growth factor (bFGF) incorporation. The results of in vitro chondrocyte culture illustrated that cells could proliferate more obviously on the microparticles with bFGF addition, but no correlation between attachment rate and bFGF was observed. On the other hand, microparticles with gyrus-patterned surface demonstrated the highest cell attachment rate and higher rate of cell growth, in particular on bFGF combined ones. It seems to be a promising candidate as a chondrocyte microparticle and could be the potential application in cartilage tissue engineering.

  8. Comparison of EMG signals recorded by surface electrodes on endotracheal tube and thyroid cartilage during monitored thyroidectomy

    Directory of Open Access Journals (Sweden)

    Feng-Yu Chiang


    Full Text Available A variety of electromyography (EMG recording methods were reported during intraoperative neural monitoring (IONM of recurrent laryngeal nerve (RLN in thyroid surgery. This study compared two surface recording methods that were obtained by electrodes on endotracheal tube (ET and thyroid cartilage (TC. This study analyzed 205 RLNs at risk in 110 patients undergoing monitored thyroidectomy. Each patient was intubated with an EMG ET during general anesthesia. A pair of single needle electrode was inserted obliquely into the TC lamina on each side. Standard IONM procedure was routinely followed, and EMG signals recorded by the ET and TC electrodes at each step were compared. In all nerves, evoked laryngeal EMG signals were reliably recorded by the ET and TC electrodes, and showed the same typical waveform and latency. The EMG signals recorded by the TC electrodes showed significantly higher amplitudes and stability compared to those by the ET electrodes. Both recording methods accurately detected 7 partial loss of signal (LOS and 2 complete LOS events caused by traction stress, but only the ET electrodes falsely detected 3 LOS events caused by ET displacement during surgical manipulation. Two patients with true complete LOS experienced temporary RLN palsy postoperatively. Neither permanent RLN palsy, nor complications from ET or TC electrodes were encountered in this study. Both electrodes are effective and reliable for recording laryngeal EMG signals during monitored thyroidectomy. Compared to ET electrodes, TC electrodes obtain higher and more stable EMG signals as well as fewer false EMG results during IONM.

  9. A technique for visualization and mapping of local cartilage thickness changes in MR images of osteoarthritic knee

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Quanxu, E-mail: [Department of Radiology, Weihai Municipal Hospital, Weihai City, Shandong Province, 164200 (China); Cheng, Yuanzhi, E-mail: [School of Computer Science and Technology, Harbin Institute of Technology, Harbin, 150001 (China); Bi, Kesen, E-mail: [Department of Radiology, Weihai Municipal Hospital, Weihai City, Shandong Province, 164200 (China); Guo, Changyong, E-mail: [School of Computer Science and Technology, Harbin Institute of Technology, Harbin, 150001 (China); Bai, Jing, E-mail: [Department of Biomedical Engineering, School of Medicine, Tsinghua University, China B209, Medical School Building, Tsinghua University, Beijing, 100084 (China); Tamura, Shinichi, E-mail: [Center for Advanced Medical Engineering and Informatics, Osaka University, D11, 2-2, Yamadaoka, Suita, Osaka 565-0871 (Japan)


    Purpose: The aim of this paper is to describe a technique for the visualization and mapping of focal, local cartilage thickness changes over time in magnetic resonance images of osteoarthritic knee. Methods: Magnetic resonance imaging was performed in 25 fresh frozen pig knee joints and 15 knees of patients with borderline to mild osteoarthritis (51.2 {+-} 6.3 years). Cartilage and corresponding bone structures were extracted by semi-automatic segmentation. Each point in the bone surface which was part of the bone-cartilage interface was assigned a cartilage thickness value. Cartilage thicknesses were computed for each point in the bone-cartilage interfaces and transferred to the bone surfaces. Moreover, we developed a three dimensional registration method for the identification of anatomically corresponding points of the bone surface to quantify local cartilage thickness changes. One of the main advantages of our method compared to other studies in the field of registration is a global optimization algorithm that does not require any initialization. Results and conclusion: The registration accuracy was 0.93 {+-} 0.05 mm (less than a voxel of magnetic resonance data). Local cartilage thickness changes were seen as having follow-up clinical study for detecting local changes in cartilage thickness. Experiment results suggest that our method was sufficiently accurate and effective for monitoring knee joint diseases.

  10. [Bionic design of articular cartilage]. (United States)

    Qin, Jun; Zhang, Wenguang; Wu, Gang; Wang, Chengtao


    Natural articular cartilage is well known as a special connective tissue with multiple effects and functions, which are important and irreplaceable, in human synovial joints. Biomedical, histological and pathological characteristics of articular cartilage, as well as biomaterial, biomechanical and bio-tribological properties thereof, are summarized from a novel aspect of bionics. Bionic design of articualr cartilage at macro-level and micro-level is carried out from three aspects, i.e., structure, material, and function; and a bionic design model of articular cartilage is set up. As a result, this basic research would be helpful to providing theoretical and practical basis for innovational design and manufacturing of new-style artificial joint with "soft-cushion bearing", and of bionic artificial cartilage.

  11. Structure of the moon's surface

    CERN Document Server

    Fielder, Gilbert


    Structure of the Moon's Surface aims to assemble and marshal relevant matter, and to produce a largely unprejudiced text which brings lunar studies up to date and stresses the importance of certain features of the Moon which have frequently been disregarded in the past, largely because of lack of knowledge about them. The book contains 14 chapters organized into two parts. Part I reviews and summarizes important physical problems. These include the liberations of the moon; height determinations of points of the moon's surface; the figure of the moon; and the moon's temperature and atmosphere.

  12. High-resolution diffusion tensor imaging of human patellar cartilage: feasibility and preliminary findings. (United States)

    Filidoro, L; Dietrich, O; Weber, J; Rauch, E; Oerther, T; Wick, M; Reiser, M F; Glaser, C


    MR diffusion tensor imaging (DTI) was used to analyze the microstructural properties of articular cartilage. Human patellar cartilage-on-bone samples were imaged at 9.4T using a diffusion-weighted SE sequence (12 gradient directions, resolution = 39 x 78 x 1500 microm(3)). Voxel-based maps of the mean diffusivity, fractional anisotropy (FA), and eigenvectors were calculated. The mean diffusivity decreased from the surface (1.45 x 10(-3) mm(2)/s) to the tide mark (0.68 x 10(-3) mm(2)/s). The FA was low (0.04-0.28) and had local maxima near the surface and in the portion of the cartilage corresponding to the radial layer. The eigenvector corresponding to the largest eigenvalue showed a distinct zonal pattern, being oriented tangentially and radially in the upper and lower portions of the cartilage, respectively. The findings correspond to current scanning electron microscopy (SEM) data on the zonal architecture of cartilage. The eigenvector maps appear to reflect the alignment of the collagenous fibers in cartilage. In view of current efforts to develop and evaluate structure-modifying therapeutic approaches in osteoarthritis (OA), DTI may offer a tool to assess the structural properties of cartilage. Copyright 2005 Wiley-Liss, Inc.

  13. Surface structure determines dynamic wetting (United States)

    Shiomi, Junichiro; Wang, Jiayu; Do-Quang, Minh; Cannon, James; Yue, Feng; Suzuki, Yuji; Amberg, Gustav


    Dynamic wetting, the spontaneous spreading process after droplet contacts a solid surface, is important in various engineering processes, such as in printing, coating, and lubrication. In the recent years, experiments and numerical simulations have greatly progressed the understanding in the dynamic wetting particularly on ``flat'' substrates. To gain further insight into the governing physics of the dynamic wetting, we perform droplet-wetting experiments on microstructured surfaces, just a few micrometers in size, with complementary numerical simulations, and investigate the dependence of the spreading rate on the microstructure geometries and fluid properties. We reveal that the influence of microstructures can be quantified in terms of a line friction coefficient for the energy dissipation rate at the contact line, and that this can be described in a simple formula in terms of the geometrical parameters of the roughness and the line-friction coefficient of the planar surface. The systematic study is also of practical importance since structures and roughness are omnipresent and their influence on spreading rate would give us additional degrees of freedom to control the dynamic wetting. This work was financially supported in part by, the Japan Society for the Promotion of Science (J.W., J.C., and J.S) and Swedish Governmental Agency for Innovation Systems (M.D.-Q. and G.A.).

  14. Structural and mechanical properties of the proliferative zone of the developing murine growth plate cartilage assessed by atomic force microscopy. (United States)

    Prein, Carina; Warmbold, Niklas; Farkas, Zsuzsanna; Schieker, Matthias; Aszodi, Attila; Clausen-Schaumann, Hauke


    The growth plate (GP) is a dynamic tissue driving bone elongation through chondrocyte proliferation, hypertrophy and matrix production. The extracellular matrix (ECM) is the major determinant of GP biomechanical properties and assumed to play a pivotal role for chondrocyte geometry and arrangement, thereby guiding proper growth plate morphogenesis and bone elongation. To elucidate the relationship between morphology and biomechanics during cartilage morphogenesis, we have investigated age-dependent structural and elastic properties of the proliferative zone of the murine GP by atomic force microscopy (AFM) from the embryonic stage to adulthood. We observed a progressive cell flattening and arrangement into columns from embryonic day 13.5 until postnatal week 2, correlating with an increasing collagen density and ECM stiffness, followed by a nearly constant cell shape, collagen density and ECM stiffness from week 2 to 4 months. At all ages, we found marked differences in the density and organization of the collagen network between the intracolumnar matrix, and the intercolumnar matrix, associated with a roughly two-fold higher stiffness of the intracolumnar matrix compared to the intercolumnar matrix. This difference in local ECM stiffness may force the cells to arrange in a columnar structure upon cell division and drive bone elongation during embryonic and juvenile development. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  15. Surface structure of AU3Cu(001)

    DEFF Research Database (Denmark)

    Eckstein, G.A.; Maupai, S.; Dakkouri, A.S.


    The surface morphology, composition, and structure of Au3Cu(001) as determined by scanning tunneling microscopy and surface x-ray diffraction are presented. Atomic resolution STM images reveal distinctive geometric features. The analysis of the surface x-ray diffraction data provides clear evidence...... for the surface structure. [S0163-1829(99)04535-X]....

  16. Change in Knee Cartilage Volume in Individuals Completing a Therapeutic Exercise Program for Knee Osteoarthritis (United States)

    Woollard, Jason D.; Gil, Alexandra B.; Sparto, Patrick; Kwoh, C. Kent; Piva, Sara R.; Farrokhi, Shawn; Powers, Christopher M.; Fitzgerald, G. Kelley


    STUDY DESIGN Prospective cohort study OBJECTIVES To characterize knee cartilage change in individuals with knee osteoarthritis (KOA) who have completed a therapeutic exercise program. BACKGROUND While therapeutic exercise is frequently used successfully to improve pain and function in individuals with KOA, no studies have reported the volume of cartilage change, or individual factors that may impact volume of cartilage change, in those completing an exercise program for KOA. METHODS 13 individuals with KOA underwent magnetic resonance imaging (MR) to quantify cartilage volume change for the weight-bearing regions of the medial and lateral femoral condyles and the entire surface of the tibial plateaus from baseline to 1-year follow-up. Measurements of body structure and function and activity levels/limitations such as the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Physical Activity Scale for the Elderly (PASE) were performed prior to the therapeutic exercise program. At 6 months from baseline follow-up clinical measurements of knee strength and motion were performed. At 1-year from baseline, imaging of the knee cartilage, knee alignment, and the WOMAC and PASE questionnaires were completed. RESULTS The central region of the medial femoral condyle (cMF) had a median volume of cartilage loss of 3.8%. The other 3 knee tibiofemoral articular surfaces had minimal median cartilage volume change. Individuals were dichotomized into progressors (n=6) and non-progressors (n=7) based on the standard error of measurement (SEM) of cartilage volume change for the cMF. Progressors were younger, had a larger body mass index, had a higher Kellgren-Lawrence grade in the medial compartment of the knee, and had a greater increase in knee varus alignment from baseline to 1-year follow-up. The progressors also had frontal plane hip and knee kinetics during baseline gait analysis that potentially increase medial knee joint loading. CONCLUSION The loss of c

  17. On real structures on rigid surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kulikov, Vik S [Steklov Mathematical Institute, Russian Academy of Sciences (Russian Federation); Kharlamov, V M [Institut de Recherche Matematique Avanee Universite Louis Pasteur et CNRS 7 rue Rene Descartes (France)


    We construct examples of rigid surfaces (that is, surfaces whose deformation class consists of a unique surface) with a particular behaviour with respect to real structures. In one example the surface has no real structure. In another it has a unique real structure, which is not maximal with respect to the Smith-Thom inequality. These examples give negative answers to the following problems: the existence of real surfaces in each deformation class of complex surfaces, and the existence of maximal real surfaces in every complex deformation class that contains real surfaces. Moreover, we prove that there are no real surfaces among surfaces of general type with p{sub g}=q=0 and K{sup 2}=9. These surfaces also provide new counterexamples to the 'Dif = Def' problem.

  18. Advances in treatment of articular cartilage injuries

    Directory of Open Access Journals (Sweden)

    Yuan-cheng LI


    Full Text Available Cartilage is a kind of terminally differentiated tissue devoid of vessel or nerve, and it is difficult to repair by itself after damage. Many studies for the treatment of cartilage injuries were performed in recent years aiming at repair of the structure and restoration of its function for injured joint. This article reviews the traditional methods of treatment for cartilage injuries, such as joint lavage with the aid of arthroscope, abrasion chondroplasty, laser abrasion and chondroplasty, and drilling of the subchondral bone-marrow space. The research advances in treatment of articular cartilage injuries with tissue engineering were summarized.

  19. A comparison of 3-T magnetic resonance imaging and computed tomography arthrography to identify structural cartilage defects of the fetlock joint in the horse. (United States)

    Hontoir, Fanny; Nisolle, Jean-François; Meurisse, Hubert; Simon, Vincent; Tallier, Max; Vanderstricht, Renaud; Antoine, Nadine; Piret, Joëlle; Clegg, Peter; Vandeweerd, Jean-Michel


    Articular cartilage defects are prevalent in metacarpo/metatarsophalangeal (MCP/MTP) joints of horses. The aim of this study was to determine and compare the sensitivity and specificity of 3-Tesla magnetic resonance imaging (3-T MRI) and computed tomography arthrography (CTA) to identify structural cartilage defects in the equine MCP/MTP joint. Forty distal cadaver limbs were imaged by CTA (after injection of contrast medium) and by 3-T MRI using specific sequences, namely, dual-echo in the steady-state (DESS), and sampling perfection with application-optimised contrast using different flip-angle evolutions (SPACE). Gross anatomy was used as the gold standard to evaluate sensitivity and specificity of both imaging techniques. CTA sensitivity and specificity were 0.82 and 0.96, respectively, and were significantly higher than those of MRI (0.41 and 0.93, respectively) in detecting overall cartilage defects (no defect vs. defect). The intra and inter-rater agreements were 0.96 and 0.92, respectively, and 0.82 and 0.88, respectively, for CT and MRI. The positive predictive value for MRI was low (0.57). CTA was considered a valuable tool for assessing cartilage defects in the MCP/MTP joint due to its short acquisition time, its specificity and sensitivity, and it was also more accurate than MRI. However, MRI permits assessment of soft tissues and subchondral bone and is a useful technique for joint evaluation, although clinicians should be aware of the limitations of this diagnostic technique, including reduced accuracy. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Surface magnetic structures in amorphous ferromagnetic microwires

    Energy Technology Data Exchange (ETDEWEB)

    Usov, N.A., E-mail: [National University of Science and Technology «MISIS», 119049 Moscow (Russian Federation); Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Russian Academy of Sciences, IZMIRAN, 108840 Troitsk, Moscow (Russian Federation); Serebryakova, O.N.; Gudoshnikov, S.A. [National University of Science and Technology «MISIS», 119049 Moscow (Russian Federation); Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Russian Academy of Sciences, IZMIRAN, 108840 Troitsk, Moscow (Russian Federation); Tarasov, V.P. [National University of Science and Technology «MISIS», 119049 Moscow (Russian Federation)


    The spatial period of magnetization perturbations that occur near the surface of magnetic nanotube or nanowire under the influence of surface magnetic anisotropy is determined by means of numerical simulation as a function of the sample geometry and material parameters. The surface magnetization distribution obtained is then used to estimate the period of the surface magnetic texture in amorphous microwire of several micrometers in diameter by means of appropriate variational procedure. The period of the surface magnetic texture in amorphous microwire is found to be significantly smaller than the wire diameter. - Highlights: • Magnetic structure may arise near the magnetic nanotube surface under the influence of surface magnetic anisotropy. • The period of the surface magnetization pattern is calculated as a function of the sample geometry. • Similar magnetic structure may exist in amorphous microwire of several micrometers in diameter. • The period of the surface magnetic structure in amorphous wire is found to be significantly smaller than the wire diameter.

  1. Brain Surface Conformal Parameterization Using Riemann Surface Structure (United States)

    Wang, Yalin; Lui, Lok Ming; Gu, Xianfeng; Hayashi, Kiralee M.; Chan, Tony F.; Toga, Arthur W.; Thompson, Paul M.; Yau, Shing-Tung


    In medical imaging, parameterized 3-D surface models are useful for anatomical modeling and visualization, statistical comparisons of anatomy, and surface-based registration and signal processing. Here we introduce a parameterization method based on Riemann surface structure, which uses a special curvilinear net structure (conformal net) to partition the surface into a set of patches that can each be conformally mapped to a parallelogram. The resulting surface subdivision and the parameterizations of the components are intrinsic and stable (their solutions tend to be smooth functions and the boundary conditions of the Dirichlet problem can be enforced). Conformal parameterization also helps transform partial differential equations (PDEs) that may be defined on 3-D brain surface manifolds to modified PDEs on a two-dimensional parameter domain. Since the Jacobian matrix of a conformal parameterization is diagonal, the modified PDE on the parameter domain is readily solved. To illustrate our techniques, we computed parameterizations for several types of anatomical surfaces in 3-D magnetic resonance imaging scans of the brain, including the cerebral cortex, hippocampi, and lateral ventricles. For surfaces that are topologically homeomorphic to each other and have similar geometrical structures, we show that the parameterization results are consistent and the subdivided surfaces can be matched to each other. Finally, we present an automatic sulcal landmark location algorithm by solving PDEs on cortical surfaces. The landmark detection results are used as constraints for building conformal maps between surfaces that also match explicitly defined landmarks. PMID:17679336

  2. Contact area measurements on structured surfaces

    DEFF Research Database (Denmark)

    Kücükyildiz, Ömer Can; Jensen, Sebastian Hoppe Nesgaard; De Chiffre, Leonardo

    In connection with the use of brass specimens featuring structured surfaces in a tribology test, an algorithm was developed for automatic measurement of the contact area by optical means.......In connection with the use of brass specimens featuring structured surfaces in a tribology test, an algorithm was developed for automatic measurement of the contact area by optical means....

  3. Differences in tibial subchondral bone structure evaluated using plain radiographs between knees with and without cartilage damage or bone marrow lesions. The Oulu knee osteoarthritis study

    Energy Technology Data Exchange (ETDEWEB)

    Hirvasniemi, Jukka [University of Oulu, Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, Oulu (Finland); Oulu University Hospital and University of Oulu, Medical Research Center Oulu, Oulu (Finland); Thevenot, Jerome; Podlipska, Jana [University of Oulu, Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, Oulu (Finland); University of Oulu, Infotech Oulu, Oulu (Finland); Guermazi, Ali [Boston University School of Medicine, Quantitative Imaging Center, Department of Radiology, Boston, MA (United States); Roemer, Frank W. [Boston University School of Medicine, Quantitative Imaging Center, Department of Radiology, Boston, MA (United States); University of Erlangen-Nuremberg, Department of Radiology, Erlangen (Germany); Nieminen, Miika T.; Saarakkala, Simo [University of Oulu, Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, Oulu (Finland); Oulu University Hospital and University of Oulu, Medical Research Center Oulu, Oulu (Finland); University of Oulu, Infotech Oulu, Oulu (Finland); Oulu University Hospital, Department of Diagnostic Radiology, Oulu (Finland)


    To investigate whether subchondral bone structure from plain radiographs is different between subjects with and without articular cartilage damage or bone marrow lesions (BMLs). Radiography-based bone structure was assessed from 80 subjects with different stages of knee osteoarthritis using entropy of Laplacian-based image (E{sub Lap}) and local binary patterns (E{sub LBP}), homogeneity index of local angles (HI{sub Angles,mean}), and horizontal (FD{sub Hor}) and vertical fractal dimensions (FD{sub Ver}). Medial tibial articular cartilage damage and BMLs were scored using the magnetic resonance imaging osteoarthritis knee score. Level of statistical significance was set to p < 0.05. Subjects with medial tibial cartilage damage had significantly higher FD{sub Ver} and E{sub LBP} as well as lower E{sub Lap} and HI{sub Angles,mean} in the medial tibial subchondral bone region than subjects without damage. FD{sub Hor}, FD{sub Ver}, and E{sub LBP} were significantly higher, whereas E{sub Lap} and HI{sub Angles,mean} were lower in the medial trabecular bone region. Subjects with medial tibial BMLs had significantly higher FD{sub Ver} and E{sub LBP} as well as lower E{sub Lap} and HI{sub Angles,mean} in medial tibial subchondral bone. FD{sub Hor}, FD{sub Ver}, and E{sub LBP} were higher, whereas E{sub Lap} and HI{sub Angles,mean} were lower in medial trabecular bone. Our results support the use of bone structural analysis from radiographs when examining subjects with osteoarthritis or at risk of having it. (orig.)

  4. Assessment of chemical species of lead accumulated in tidemarks of human articular cartilage by X-ray absorption near-edge structure analysis

    Energy Technology Data Exchange (ETDEWEB)

    Meirer, Florian [Atominstitut, Vienna University of Technology, 1020 Wien (Austria); MiNALab, CMM-Irst, Fondazione Bruno Kessler, Via Sommarive 18, 38123 Trento (Italy); Pemmer, Bernhard, E-mail: [Atominstitut, Vienna University of Technology, 1020 Wien (Austria); Pepponi, Giancarlo [MiNALab, CMM-Irst, Fondazione Bruno Kessler, Via Sommarive 18, 38123 Trento (Italy); Zoeger, Norbert; Wobrauschek, Peter [Atominstitut, Vienna University of Technology, 1020 Wien (Austria); Sprio, Simone; Tampieri, Anna [Istituto di Scienza e Tecnologia dei Materiali Ceramici CNR, Faenca (Italy); Goettlicher, Joerg; Steininger, Ralph; Mangold, Stefan [Institute for Synchrotron Radiation, Karlsruhe Institute of Technology, Campus South, 76344 Eggenstein-Leopoldshafen (Germany); Roschger, Paul [Ludwig Boltzmann Institute of Osteology, Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 4th Medical Department, Hanusch Hospital, Vienna (Austria); Berzlanovich, Andrea [Department of Forensic Medicine, Medical University of Vienna, A-1090 Vienna (Austria); Hofstaetter, Jochen G. [Ludwig Boltzmann Institute of Osteology, Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 4th Medical Department, Hanusch Hospital, Vienna (Austria); Department of Orthopaedics, Vienna General Hospital, Medical University of Vienna, A-1090 Vienna (Austria); Streli, Christina [Atominstitut, Vienna University of Technology, 1020 Wien (Austria)


    Lead is a toxic trace element that shows a highly specific accumulation in the transition zone between calcified and non-calcified articular cartilage, the so-called ‘tidemark’. Excellent agreement has been found between XANES spectra of synthetic Pb-doped carbonated hydroxyapatite and spectra obtained in the tidemark region and trabecular bone of normal human samples, confirming that in both tissues Pb is incorporated into the hydroxyapatite crystal structure of bone. During this study the µ-XANES set-up at the SUL-X beamline at ANKA was tested and has proven to be well suited for speciation of lead in human mineralized tissue samples. A highly specific accumulation of the toxic element lead was recently measured in the transition zone between non-calcified and calcified normal human articular cartilage. This transition zone, the so-called ‘tidemark’, is considered to be an active calcification front of great clinical importance. However, little is known about the mechanisms of accumulation and the chemical form of Pb in calcified cartilage and bone. Using spatially resolved X-ray absorption near-edge structure analysis (µ-XANES) at the Pb L{sub 3}-edge, the chemical state of Pb in the osteochondral region was investigated. The feasibility of the µ-XANES set-up at the SUL-X beamline (ANKA synchrotron light source) was tested and confirmed by comparing XANES spectra of bulk Pb-reference compounds recorded at both the XAS and the SUL-X beamline at ANKA. The µ-XANES set-up was then used to investigate the tidemark region of human bone (two patella samples and one femoral head sample). The spectra recorded at the tidemark and at the trabecular bone were found to be highly correlated with the spectra of synthetic Pb-doped carbonated hydroxyapatite, suggesting that in both of these very different tissues Pb is incorporated into the hydroxyapatite structure.

  5. Thickness Distribution of Glenohumeral Joint Cartilage. (United States)

    Schleich, Christoph; Bittersohl, Bernd; Antoch, Gerald; Krauspe, Rüdiger; Zilkens, Christoph; Kircher, Jörn


    High-resolution 3-dimensional cartilage-specific magnetic resonance imaging (MRI) was performed at 3 T to test the following hypotheses: (1) there is a nonuniform cartilage thickness distribution both on the proximal humerus and on the glenoid surface and (2) the glenohumeral joint as a combined system is congruent with the level of the joint cartilage surface without substantial radial mismatch. Inclusion of 38 volunteers (19 females, mean age 24.34 ± 2.22 years; range 21-29 years) in a prospective study. Measurements of: cartilage thickness in 3 regions and 3 zones; radius of both circles (glenoid and humeral cartilage) for congruency calculation using 3-T MRI with 3-dimensional dual-echo steady-state sequence with water excitation. A homogenous mean cartilage thickness (1.2-1.5 mm) and slightly higher values for the glenoidal articulating surface radii both in the mid-paracoronar section (2.4 vs. 2.1 cm, P cartilage changes at the shoulder for future studies.

  6. Atomic and electronic structures of novel silicon surface structures

    Energy Technology Data Exchange (ETDEWEB)

    Terry, J.H. Jr.


    The modification of silicon surfaces is presently of great interest to the semiconductor device community. Three distinct areas are the subject of inquiry: first, modification of the silicon electronic structure; second, passivation of the silicon surface; and third, functionalization of the silicon surface. It is believed that surface modification of these types will lead to useful electronic devices by pairing these modified surfaces with traditional silicon device technology. Therefore, silicon wafers with modified electronic structure (light-emitting porous silicon), passivated surfaces (H-Si(111), Cl-Si(111), Alkyl-Si(111)), and functionalized surfaces (Alkyl-Si(111)) have been studied in order to determine the fundamental properties of surface geometry and electronic structure using synchrotron radiation-based techniques.

  7. Numerical simulation of condensation on structured surfaces. (United States)

    Fu, Xiaowu; Yao, Zhaohui; Hao, Pengfei


    Condensation of liquid droplets on solid surfaces happens widely in nature and industrial processes. This phase-change phenomenon has great effect on the performance of some microfluidic devices. On the basis of micro- and nanotechnology, superhydrophobic structured surfaces can be well-fabricated. In this work, the nucleating and growth of droplets on different structured surfaces are investigated numerically. The dynamic behavior of droplets during the condensation is simulated by the multiphase lattice Boltzmann method (LBM), which has the ability to incorporate the microscopic interactions, including fluid-fluid interaction and fluid-surface interaction. The results by the LBM show that, besides the chemical properties of surfaces, the topography of structures on solid surfaces influences the condensation process. For superhydrophobic surfaces, the spacing and height of microridges have significant influence on the nucleation sites. This mechanism provides an effective way for prevention of wetting on surfaces in engineering applications. Moreover, it suggests a way to prevent ice formation on surfaces caused by the condensation of subcooled water. For hydrophilic surfaces, however, microstructures may be submerged by the liquid films adhering to the surfaces. In this case, microstructures will fail to control the condensation process. Our research provides an optimized way for designing surfaces for condensation in engineering systems.

  8. A surface measure for probabilistic structural computations. (United States)

    Schmidt, J P; Chen, C C; Cooper, J L; Altman, R B


    Computing three-dimensional structures from sparse experimental constraints requires method for combining heterogeneous sources of information, such as distances, angles, and measures of total volume, shape, and surface. For some types of information, such as distances between atoms, numerous methods are available for computing structures that satisfy the provided constraints. It is more difficult, however, to use information about the degree to which an atom is on the surface or buried as a useful constraint during structure computations. Surface measures have been used as accept/reject criteria for previously computed structures, but this is not an efficient strategy. In this paper, we investigate the efficacy of applying a surface measure in the computation of molecular structure, using a method of probabilistic least square computations which facilitates the introduction of multiple, noisy, heterogeneous data sources. For this purpose, we introduce a simple purely geometrical measure of surface proximity called maximal conic view (MCV). MCV is efficiently computable and differentiable, and is hence well suited to driving a structural optimization method based, in part, on surface data. As an initial validation, we show that MCV correlates well with known measures for total exposed surface area. We use this measure in our experiments to show that information about surface proximity (derived from theory or experiment, for example) can be added to a set of distance measurements to increase significantly the quality of the computed structure. In particular, when 30 to 50 percent of all possible short-range distances are provided, the addition of surface information improves the quality of the computed structure (as measured by RMS fit) by as much as 80 percent. Our results demonstrate that knowledge of which atoms are on the surface and which are buried can be used as a powerful constraint in estimating molecular structure.

  9. Relationships Between Quantitative Pulse-Echo Ultrasound Parameters from the Superficial Zone of the Human Articular Cartilage and Changes in Surface Roughness, Collagen Content or Collagen Orientation Caused by Early Degeneration. (United States)

    Kiyan, Wataru; Ito, Akira; Nakagawa, Yasuaki; Mukai, Shogo; Mori, Koji; Arai, Tatsuo; Uchino, Eiichiro; Okuno, Yasushi; Kuroki, Hiroshi


    We aimed to quantitatively investigate the relationship between amplitude-based pulse-echo ultrasound parameters and early degeneration of the knee articular cartilage. Twenty samples from six human femoral condyles judged as grade 0 or 1 according to International Cartilage Repair Society grading were assessed using a 15-MHz pulsed-ultrasound 3-D scanning system ex vivo. Surface roughness (R q ), average collagen content (A 1 ) and collagen orientation (A 12 ) in the superficial zone of the cartilage were measured via laser microscopy and Fourier transform infrared imaging spectroscopy. Multiple regression analysis with a linear mixed-effects model (LMM) revealed that a time-domain reflection coefficient at the cartilage surface (R c ) had a significant coefficient of determination with R q and A 12 (R LMMm 2 =0.79); however, R c did not correlate with A 1 . Concerning the collagen characteristic in the superficial zone, R c was found to be a sensitive indicator reflecting collagen disorganization, not collagen content, for the early degeneration samples. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  10. Structural effects of sprifermin in knee osteoarthritis: a post-hoc analysis on cartilage and non-cartilaginous tissue alterations in a randomized controlled trial. (United States)

    Roemer, Frank W; Aydemir, Aida; Lohmander, Stefan; Crema, Michel D; Marra, Monica Dias; Muurahainen, Norma; Felson, David T; Eckstein, Felix; Guermazi, Ali


    A recent publication on efficacy of Sprifermin for knee osteoarthritis (OA) using quantitatively MRI-defined central medial tibio-femoral compartment cartilage thickness as the structural primary endpoint reported no statistically significant dose response. However, Sprifermin was associated with statistically significant, dose-dependent reductions in loss of total and lateral tibio-femoral cartilage thickness. Based on these preliminary promising data a post-hoc analysis of secondary assessment and endpoints was performed to evaluate potential effects of Sprifermin on semi-quantitatively evaluated structural MRI parameters. Aim of the present analysis was to determine effects of sprifermin on several knee joint tissues over a 12 month period. 1.5 T or 3 T MRIs were acquired at baseline and 12 months follow-up using a standard protocol. MRIs were read according to the Whole-Organ Magnetic Resonance Imaging Score (WORMS) scoring system (in 14 articular subregions) by four muskuloskeletal radiologists independently. Analyses focused on semiquantitative changes in the 100 μg subgroup and matching placebo of multiple MRI-defined structural alterations. Analyses included a delta-subregional and delta-sum approach for the whole knee and the medial and lateral tibio-femoral (MTFJ, LTFJ), and patello-femoral (PFJ) compartments, taking into account number of subregions showing no change, improvement or worsening and changes in the sum of subregional scores. Mann-Whitney - Wilcoxon tests assessed differences between groups. Fifty-seven and 18 patients were included in the treatment and matched placebo subgroups. Less worsening of cartilage damage was observed from baseline to 12 months in the PFJ (0.02, 95 % confidence interval (CI) (-0.04, 0.08) vs. placebo 0.22, 95 % CI (-0.05, 0.49), p = 0.046). For bone marrow lesions (BMLs), more improvement was observed from 6 to 12 months for whole knee analyses (-0.14, 95 % CI (-0.48, 0.19) vs. placebo 0.44, 95

  11. Magnetic Resonance Imaging of Cartilage Repair (United States)

    Trattnig, Siegfried; Winalski, Carl S.; Marlovits, Stephan; Jurvelin, Jukka S.; Welsch, Goetz H.; Potter, Hollis G.


    Articular cartilage lesions are a common pathology of the knee joint, and many patients may benefit from cartilage repair surgeries that offer the chance to avoid the development of osteoarthritis or delay its progression. Cartilage repair surgery, no matter the technique, requires a noninvasive, standardized, and high-quality longitudinal method to assess the structure of the repair tissue. This goal is best fulfilled by magnetic resonance imaging (MRI). The present article provides an overview of the current state of the art of MRI of cartilage repair. In the first 2 sections, preclinical and clinical MRI of cartilage repair tissue are described with a focus on morphological depiction of cartilage and the use of functional (biochemical) MR methodologies for the visualization of the ultrastructure of cartilage repair. In the third section, a short overview is provided on the regulatory issues of the United States Food and Drug Administration (FDA) and the European Medicines Agency (EMEA) regarding MR follow-up studies of patients after cartilage repair surgeries. PMID:26069565

  12. Intrinsic Structure, Surface Properties, and Dissociation Reactions on Metal Surfaces. (United States)

    Liyanage, Lalantha Saman

    The original Surface Embedded Green Function (SEGF) method has been used to perform self-consistent calculations of the surface electronic structure of (1x1)Pt(001), O/Pt(001) and (1x5)Pt(001). Calculated work functions, surface state and surface resonance bands, and densities of states are compared with experiment and with earlier slab calculations. The calculated work function for all three surfaces is in excellent agreement with experiment. In general, other results are also consistent with experiment. Total and difference charge density plots are used to illustrate details of O-Pt bonding. Analysis of the surface charge density of (1x1)Pt(001) shows an increase in sp bonding charge which leads to a compressive surface stress, and may help explain the surface reconstruction. The stress is reduced in the O/Pt(001) surface, indicating oxygen stabilization of the (1x1) phase. The calculated difference-DOS curve between (1x1)Pt(001) and (1x5)Pt(001) reveals a reduction of the DOS near the Fermi level for the (1x5) phase, which helps explain the low chemical activity of the reconstructed surface. The method of removing the two-dimensional inversion symmetry requirement from the original SEGF technique is discussed in detail. The generalized SEGF method is tested by applying it to the Al(111) surface. The results obtained by the study are in excellent agreement with experiment and with slab calculations.

  13. Structure and functions of fungal cell surfaces (United States)

    Nozawa, Y.


    A review with 24 references on the biochemistry, molecular structure, and function of cell surfaces of fungi, especially dermatophytes: the chemistry and structure of the cell wall, the effect of polyene antibiotics on the morphology and function of cytoplasmic membranes, and the chemical structure and function of pigments produced by various fungi are discussed.

  14. Coherent flow structures at earth's surface

    National Research Council Canada - National Science Library

    Venditti, J.G; Best, J.L; Church, M; Hardy, R.J


    This book reviews the recent progress in the study of the turbulent flows that sculpt the Earth's surface, focusing in particular on the organized structures that have been identified in recent years...

  15. Designing visual appearance using a structured surface

    DEFF Research Database (Denmark)

    Johansen, Villads Egede; Thamdrup, Lasse Højlund; Smitrup, Christian


    We present an approach for designing nanostructured surfaces with prescribed visual appearances, starting at design analysis and ending with a fabricated sample. The method is applied to a silicon wafer structured using deep ultraviolet lithography and dry etching and includes preliminary design...... followed by numerical and experimental verification. The approach comprises verifying all design and fabrication steps required to produce a desired appearance. We expect that the procedure in the future will yield structurally colored surfaces with appealing prescribed visual appearances....

  16. Deginerative changes of femoral articular cartilage in the knee : comparative study of specimen sonography and pathology

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ju Youn; Hong, Sung Hwan; Sohn, Jin Hee; Wee, Young Hoon; Chang, Jun Dong; Park, Hong Seok; Lee, Eil Seoung; Kang Ik Won [Hallym Univ. College of Medicine, Seoul (Korea, Republic of)


    To determine the sonographic findings of degenerative change in femoral articular cartilage of the knee by comparative study of specimen sonography and pathology. We obtained 40 specimens of cartilage of the femur (20 medial and 20 lateral condylar) from 20 patients with osteoarthritis of the knee who had undergone total knee replacement. The specimens were placed in a saline-filled container and sonography was performed using a 10-MHz linear transducer. Sonographic abnormalities were evaluated at the cartilage surface, within the cartilage, and at the bone-cartilage interface, and were compared with the corresponding pathologic findings. In addition, cartilage thickness was measured at a representative portion of each femoral cartilage specimen and was compared with the thickness determined by sonography. 'Dot' lesions, irregularity or loss of the hyperechoic line, were demonstrated by sonography at the saline-cartilage interface of 14 cartilages. Pathologic examination showed that these findings corresponded to cleft, detachment, erosion, and degeneration. Irregularities in the hyperechoic line at the bone-cartilage interface were revealed by sonography in eight cartilages and were related to irregularity or loss of tidemark, downward displacement of the cartilage, and subchondral callus formation. Dot lesions, corresponding to cleft and degeneration, were noted within one cartilage. Cartilage thickness measured on specimen and by sonography showed no significant difference (p=0.446). Specimen sonography suggested that articular cartilage underwent degenerative histopathological change. Cartilage thickness measured by sonography exactly reflected real thickness.

  17. Induction of mesenchymal stem cell chondrogenic differentiation and functional cartilage microtissue formation for in vivo cartilage regeneration by cartilage extracellular matrix-derived particles. (United States)

    Yin, Heyong; Wang, Yu; Sun, Zhen; Sun, Xun; Xu, Yichi; Li, Pan; Meng, Haoye; Yu, Xiaoming; Xiao, Bo; Fan, Tian; Wang, Yiguo; Xu, Wenjing; Wang, Aiyuan; Guo, Quanyi; Peng, Jiang; Lu, Shibi


    We propose a method of preparing a novel cell carrier derived from natural cartilage extracellular matrix (ECM), designated cartilage ECM-derived particles (CEDPs). Through a series of processes involving pulverization, sieving, and decellularization, fresh cartilage was made into CEDPs with a median diameter of 263 ± 48 μm. Under microgravity culture conditions in a rotary cell culture system (RCCS), bone marrow stromal cells (BMSCs) can proliferate rapidly on the surface of CEDPs with high viability. Histological evaluation and gene expression analysis indicated that BMSCs were differentiated into mature chondrocytes after 21 days of culture without the use of exogenous growth factors. Functional cartilage microtissue aggregates of BMSC-laden CEDPs formed as time in culture increased. Further, the microtissue aggregates were directly implanted into trochlear cartilage defects in a rat model (CEDP+MSC group). Gait analysis and histological results indicated that the CEDP+MSC group obtained better and more rapid joint function recovery and superior cartilage repair compared to the control groups, in which defects were treated with CEDPs alone or only fibrin glue, at both 6 and 12 weeks after surgery. In conclusion, the innovative cell carrier derived from cartilage ECM could promote chondrogenic differentiation of BMSCs, and the direct use of functional cartilage microtissue facilitated cartilage regeneration. This strategy for cell culture, stem cell differentiation and one-step surgery using cartilage microtissue for cartilage repair provides novel prospects for cartilage tissue engineering and may have further broad clinical applications. We proposed a method to prepare a novel cell carrier derived from natural cartilage ECM, termed cartilage ECM-derived particles (CEDPs), which can support proliferation of MSCs and facilitate their chondrogenic differentiation. Further, the direct use of functional cartilage microtissue of MSC-laden CEDP aggregates for

  18. Surface and deep structures in graphics comprehension. (United States)

    Schnotz, Wolfgang; Baadte, Christiane


    Comprehension of graphics can be considered as a process of schema-mediated structure mapping from external graphics on internal mental models. Two experiments were conducted to test the hypothesis that graphics possess a perceptible surface structure as well as a semantic deep structure both of which affect mental model construction. The same content was presented to different groups of learners by graphics from different perspectives with different surface structures but the same deep structure. Deep structures were complementary: major features of the learning content in one experiment became minor features in the other experiment, and vice versa. Text was held constant. Participants were asked to read, understand, and memorize the learning material. Furthermore, they were either instructed to process the material from the perspective supported by the graphic or from an alternative perspective, or they received no further instruction. After learning, they were asked to recall the learning content from different perspectives by completing graphs of different formats as accurately as possible. Learners' recall was more accurate if the format of recall was the same as the learning format which indicates surface structure influences. However, participants also showed more accurate recall when they remembered the content from a perspective emphasizing the deep structure, regardless of the graphics format presented before. This included better recall of what they had not seen than of what they really had seen before. That is, deep structure effects overrode surface effects. Depending on context conditions, stimulation of additional cognitive processing by instruction had partially positive and partially negative effects.

  19. Diffusion of Paramagnetically Labeled Proteins in Cartilage: Enhancement of the 1-D NMR Imaging Technique (United States)

    Foy, Brent D.; Blake, Joseph


    Quantifying the diffusive transport of large molecules in avascular cartilage tissue is important both for planning potential pharamacological treatments and for gaining insight into the molecular-scale structure of cartilage. In this work, the diffusion coefficients of gadolinium-DTPA and Gd-labeled versions of four proteins-lysozyme, trypsinogen, ovalbumin, and bovine serum albumin (BSA) with molecular weights of 14,300, 24,000, 45,000, and 67,000, respectively-have been measured in healthy and degraded calf cartilage. The experimental technique relies on the effect of the paramagnetic on the relaxation properties of the surrounding water, combined with the time course of a 1-dimensional spatial profile of the water signal in the cartilage sample. The enhanced technique presented here does not require a prior measurement of the relaxivity of the paramagnetic compound in the sample of interest. The data are expressed as the ratio of the diffusion coefficient of a compound in cartilage to its diffusion coefficient in water. For healthy cartilage, this ratio was 0.34 ± 0.07 for Gd-DTPA, the smallest compound, and fell to 0.3 ± 0.1 for Gd-lysozyme, 0.08 ± 0.04 for Gd-trypsinogen, and 0.07 ± 0.04 for Gd-ovalbumin. Gd-BSA did not appear to enter healthy cartilage tissue beyond a surface layer. After the cartilage had been degraded by 24-h trypsinization, these ratios were 0.60 ± 0.03 for Gd-DTPA, 0.40 ± 0.08 for Gd-lysozyme, 0.42 ± 0.09 for Gd-trypsinogen, 0.16 ± 0.14 for Gd-ovalbumin, and 0.11 ± 0.05 for Gd-BSA. Thus, degradation of the cartilage led to increases in the diffusion coefficient of up to fivefold for the Gd-labeled proteins. These basic transport parameters yield insights on the nature of pore sizes and chemical-matrix interactions in the cartilage tissue and may prove diagnostically useful for identifying the degree and nature of damage to cartilage.

  20. The structure of reconstructed chalcopyrite surfaces (United States)

    Thinius, Sascha; Islam, Mazharul M.; Bredow, Thomas


    Chalcopyrite (CuFeS2) surfaces are of major interest for copper exploitation in aqueous solution, called leaching. Since leaching is a surface process knowledge of the surface structure, bonding pattern and oxidation states is important for improving the efficiency. At present such information is not available from experimental studies. Therefore a detailed computational study of chalcopyrite surfaces is performed. The structures of low-index stoichiometric chalcopyrite surfaces {hkl} h, k, l ∈ {0, 1, 2} have been studied with density functional theory (DFT) and global optimization strategies. We have applied ab initio molecular dynamics (MD) in combination with simulated annealing (SA) in order to explore possible reconstructions via a minima hopping (MH) algorithm. In almost all cases reconstruction involving substantial rearrangement has occurred accompanied by reduction of the surface energy. The analysis of the change in the coordination sphere and migration during reconstruction reveals that S-S dimers are formed on the surface. Further it was observed that metal atoms near the surface move toward the bulk forming metal alloys passivated by sulfur. The obtained surface energies of reconstructed surfaces are in the range of 0.53-0.95 J/m2.

  1. Study of physical, chemical and structural effects caused by ionizing radiation and preservation on human costal cartilage; Estudo dos efeitos fisicos, quimicos e estruturais ocasionados pela radiacao ionizante e preservacao em cartilagem costal humana

    Energy Technology Data Exchange (ETDEWEB)

    Martinho Junior, Antonio Carlos


    Tissue Banks around the world have stored human cartilages obtained from cadaver donors for use in several kinds of reconstructive surgeries. To ensure that such tissues are not contaminated, they have been sterilized with ionizing radiation. However, high doses of gamma radiation may cause undesirable changes in the tissues, decreasing the mechanical properties of the grafts. In this work, we evaluate physical/chemical and structural changes in deep-frozen (-70 deg C) or high concentration of glycerol (> 98%) preserved costal cartilage, before and after sterilization by ionizing radiation at 3 different doses (15, 25 and 50 kGy). Samples of human costal cartilage were obtained from 20 cadaver donors ranging between 18 and 55 years old. A {sup 60}Co irradiator was used as irradiation source. Thermogravimetry (TG), Optical Coherence Tomography (OCT) and mechanical tension and compression tests were carried out to evaluate the changes in the cartilage. Regarding the thermogravimetric results, the obtained data has shown that the TG curves have the same pattern independently of the sample irradiated or not. On the other hand, non-irradiated samples showed great variability of thermogravimetric curves among different donors and for the same donor. Concerning the mechanical tests, when cartilages were irradiated with 15 kGy, their mechanical strength to tension was increased about 24%, in both deep-froze and preserved in glycerol samples. Samples deep-frozen, when irradiated with 25 and 50 kGy, presented a decrease of their mechanical behavior smaller than those preserved in high concentrations of glycerol and irradiated with the same dose. Therefore, deep-frozen cartilages can be sterilized with doses until 50 kGy and cartilages preserved in high concentrations of glycerol can be sterilized with doses until 25 kGy without significant changes in their bio-mechanical properties.(author)

  2. Cartilage tissue engineering: its potential and uses. (United States)

    Kuo, Catherine K; Li, Wan-Ju; Mauck, Robert L; Tuan, Rocky S


    The prevalent nature of osteoarthritis, a cartilage degenerative disease that results in the erosion of joint surfaces and loss of mobility, underscores the importance of developing functional articular cartilage replacement. Recent research efforts have focused on tissue engineering as a promising approach for cartilage regeneration and repair. Tissue engineering is a multidisciplinary research area that incorporates both biological and engineering principles for the purpose of generating new, living tissues to replace the diseased/damaged tissue and restore tissue/organ function. This review surveys and highlights the current concepts and recent progress in cartilage tissue engineering, and discusses the challenges and potential of this rapidly advancing field of biomedical research. Cartilage tissue engineering is critically dependent on selection of appropriate cells (differentiated or progenitor cells); fabrication and utilization of biocompatible and mechanically suitable scaffolds for cell delivery; stimulation with chondrogenically bioactive molecules introduced in the form of recombinant proteins or via gene transfer; and application of dynamic, mechanical loading regimens for conditioning of the engineered tissue constructs, including the design of specialized biomechanically active bioreactors. Cell selection, scaffold design and biological stimulation remain the challenges of function tissue engineering. Successful regeneration or replacement of damaged or diseased cartilage will depend on future advances in our understanding of the biology of cartilage and stem cells and technological development in engineering.

  3. Sub-µm structured lotus surfaces manufacturing

    DEFF Research Database (Denmark)

    Worgull, Matthias; Heckele, Mathias; Mappes, Timo


    Sub-lm structured surfaces allow modifying the behavior of polymer films or components. Especially in micro-fluidics a lotus-like characteristic is requested for many applications. Structure details with a high aspect ratio are necessary to decouple the bottom and the top of the functional layer....

  4. Sub-µ structured Lotus Surfaces Manufacturing

    DEFF Research Database (Denmark)

    Worgull, Matthias; Heckele, Mathias; Mappes, Timo


    Sub-micro structured surfaces allow modifying the behavior of polymer films or components. Especially in micro fluidics a lotus-like characteristic is requested for many applications. Structure details with a high aspect ratio are necessary to decouple the bottom and the top of the functional lay...

  5. Colloids with high-definition surface structures (United States)

    Chen, Hsien-Yeh; Rouillard, Jean-Marie; Gulari, Erdogan; Lahann, Joerg


    Compared with the well equipped arsenal of surface modification methods for flat surfaces, techniques that are applicable to curved, colloidal surfaces are still in their infancy. This technological gap exists because spin-coating techniques used in traditional photolithographic processes are not applicable to the curved surfaces of spherical objects. By replacing spin-coated photoresist with a vapor-deposited, photodefinable polymer coating, we have now fabricated microstructured colloids with a wide range of surface patterns, including asymmetric and chiral surface structures, that so far were typically reserved for flat substrates. This high-throughput method can yield surface-structured colloidal particles at a rate of ≈107 to 108 particles per operator per day. Equipped with spatially defined binding pockets, microstructured colloids can engage in programmable interactions, which can lead to directed self-assembly. The ability to create a wide range of colloids with both simple and complex surface patterns may contribute to the genesis of previously unknown colloidal structures and may have important technological implications in a range of different applications, including photonic and phononic materials or chemical sensors. PMID:17592149

  6. Stress relaxation and cartilage shaping under laser radiation (United States)

    Sobol, Emil N.; Sviridov, Alexander P.; Bagratashvili, Victor N.; Omelchenko, Alexander I.; Ovchinnikov, Yuriy M.; Shekhter, Anatoliy B.; Downes, S.; Howdle, Steven; Jones, Nicholas; Lowe, J.


    The problem of a purposeful change of the shape of cartilage is of great importance for otolaryngology, orthopaedics, and plastic surgery. In 1992 we have found a possibility of controlled shaping of cartilage under moderate laser heating. This paper presents new results in studies of that phenomenon. We have measured temperature and stress in a tissue undergoing to irradiation with a Holmium laser. Study of cartilage structure allowed us to find conditions for laser shaping without pronounced alterations in the structure of matrix.

  7. Semi-automatic 3D segmentation of costal cartilage in CT data from Pectus Excavatum patients (United States)

    Barbosa, Daniel; Queirós, Sandro; Rodrigues, Nuno; Correia-Pinto, Jorge; Vilaça, J.


    One of the current frontiers in the clinical management of Pectus Excavatum (PE) patients is the prediction of the surgical outcome prior to the intervention. This can be done through computerized simulation of the Nuss procedure, which requires an anatomically correct representation of the costal cartilage. To this end, we take advantage of the costal cartilage tubular structure to detect it through multi-scale vesselness filtering. This information is then used in an interactive 2D initialization procedure which uses anatomical maximum intensity projections of 3D vesselness feature images to efficiently initialize the 3D segmentation process. We identify the cartilage tissue centerlines in these projected 2D images using a livewire approach. We finally refine the 3D cartilage surface through region-based sparse field level-sets. We have tested the proposed algorithm in 6 noncontrast CT datasets from PE patients. A good segmentation performance was found against reference manual contouring, with an average Dice coefficient of 0.75±0.04 and an average mean surface distance of 1.69+/-0.30mm. The proposed method requires roughly 1 minute for the interactive initialization step, which can positively contribute to an extended use of this tool in clinical practice, since current manual delineation of the costal cartilage can take up to an hour.

  8. A Triphasic Orthotropic Laminate Model for Cartilage Curling Behavior: Fixed Charge Density vs. Mechanical Properties Inhomogeneity (United States)

    Wan, Leo Q.; Guo, X. Edward; Mow, Van C.


    Osmotic pressure and associated residual stresses play important roles in cartilage development and biomechanical function. The curling behavior of articular cartilage was believed to be the combination of results from the osmotic pressure derived from fixed negative charges on proteoglycans and the structural and compositional and material property inhomogeneities within the tissue. In the present study, the in vitro swelling and curling behaviors of thin strips of cartilage were analyzed with a new structural model using the triphasic mixture theory with a collagen-proteoglycan solid matrix composed of a three-layered laminate with each layer possessing a distinct set of orthotropic properties. A conewise linear elastic matrix was also incorporated to account for the well-known tension-compression nonlinearity of the tissue. This model can account, for the first time, for the swelling-induced curvatures found in published experimental results on excised cartilage samples. The results suggest that for a charged hydrated soft tissue, such as articular cartilage, the balance of proteoglycan swelling and the collagen restraining within the solid matrix is the origin of the in situ residual stress, and that the layered collagen ultrastructure, e.g., relatively dense and with high stiffness at the articular surface, play the dominate role in determining curling behaviors of such tissues. PMID:20370250

  9. A triphasic orthotropic laminate model for cartilage curling behavior: fixed charge density versus mechanical properties inhomogeneity. (United States)

    Wan, Leo Q; Guo, X Edward; Mow, Van C


    Osmotic pressure and associated residual stresses play important roles in cartilage development and biomechanical function. The curling behavior of articular cartilage was believed to be the combination of results from the osmotic pressure derived from fixed negative charges on proteoglycans and the structural and compositional and material property inhomogeneities within the tissue. In the present study, the in vitro swelling and curling behaviors of thin strips of cartilage were analyzed with a new structural model using the triphasic mixture theory with a collagen-proteoglycan solid matrix composed of a three-layered laminate with each layer possessing a distinct set of orthotropic properties. A conewise linear elastic matrix was also incorporated to account for the well-known tension-compression nonlinearity of the tissue. This model can account, for the first time, for the swelling-induced curvatures found in published experimental results on excised cartilage samples. The results suggest that for a charged-hydrated soft tissue, such as articular cartilage, the balance of proteoglycan swelling and the collagen restraining within the solid matrix is the origin of the in situ residual stress, and that the layered collagen ultrastructure, e.g., relatively dense and with high stiffness at the articular surface, play the dominate role in determining curling behaviors of such tissues.

  10. Articular Cartilage Regeneration: An Update of Possible Treatment Approaches

    Directory of Open Access Journals (Sweden)

    Ray Marks


    Full Text Available BACKGROUND: Osteoarthritis, a widespread chronically disabling disorder primarily affecting articular cartilage is said to be irreversible. Researchers have however, been examining processes and methods of promoting articular cartilage repair for some time. QUESTIONS: Can a case be made for the possibility of restoring osteoarthritic cartilage? How advanced is this undertaking? What barriers exist in translating basic studies in the clinical realm? What physical modalities are deemed efficacious in promoting cartilage structure? METHODS: All relevant publications detailing articular cartilage repair themes in the leading databases were examined. Specific emphasis was placed on a broad array of efforts and observations concerning articular cartilage and its repair. Articles of historic significance and more current strategies designed to foster cartilage repair were focused on, and reported in narrative form. Ideas extracted from the voluminous literature were those that answered one or more of the key questions driving this research. RESULTS: Numerous attempts have been made over time to foster cartilage repair, using a variety of approaches such as creating artificial cartilage, and transplanting stem cells into damaged cartilage to promote repair. Most current strategies are forged in laboratories and do not always account for the complex disease process, and the importance mechanical and inflammatory determinants play in the disease. However, manipulating biophysical, and biomechanical stimuli favorably is likely to hold promise for attenuating destruction of/or for fostering cartilage viability and repair, even in the presence of adverse osteoarthritic cartilage tissue changes. CONCLUSION: More work is needed to examine the key upstream determinants leading to articular cartilage destruction, and to enhancing the viability of the tissue. Employing carefully construed therapeutic strategies known to impact articular cartilage homeostasis

  11. The acutely ACL injured knee assessed by MRI: changes in joint fluid, bone marrow lesions, and cartilage during the first year

    DEFF Research Database (Denmark)

    Frobell, R B; Le Graverand, M-P; Buck, R


    OBJECTIVES: To investigate changes in the knee during the first year after acute rupture of the anterior cruciate ligament (ACL) of volumes of joint fluid (JF), bone marrow lesions (BMLs), and cartilage volume (VC), and cartilage thickness (ThCcAB) and cartilage surface area (AC). To identify...... treated with ACL reconstruction followed by a structured rehabilitation program and 24 subjects were treated with structured rehabilitation only. Morphometric data were acquired from computer-assisted segmentation of MR images. Morphometric cartilage change was reported as mean change divided...... (TrF), while an increase of VC and ThCcAB was found in the central medial femur (cMF) (SRM greater than 0.477). ACL reconstruction was directly and significantly related to increased JF volume at 3 and 6 months (P

  12. Nanomechanics of the Cartilage Extracellular Matrix (United States)

    Han, Lin; Grodzinsky, Alan J.; Ortiz, Christine


    Cartilage is a hydrated biomacromolecular fiber composite located at the ends of long bones that enables proper joint lubrication, articulation, loading, and energy dissipation. Degradation of extracellular matrix molecular components and changes in their nanoscale structure greatly influence the macroscale behavior of the tissue and result in dysfunction with age, injury, and diseases such as osteoarthritis. Here, the application of the field of nanomechanics to cartilage is reviewed. Nanomechanics involves the measurement and prediction of nanoscale forces and displacements, intra- and intermolecular interactions, spatially varying mechanical properties, and other mechanical phenomena existing at small length scales. Experimental nanomechanics and theoretical nanomechanics have been applied to cartilage at varying levels of material complexity, e.g., nanoscale properties of intact tissue, the matrix associated with single cells, biomimetic molecular assemblies, and individual extracellular matrix biomolecules (such as aggrecan, collagen, and hyaluronan). These studies have contributed to establishing a fundamental mechanism-based understanding of native and engineered cartilage tissue function, quality, and pathology.

  13. The minor collagens in articular cartilage

    DEFF Research Database (Denmark)

    Luo, Yunyun


    Articular cartilage is a connective tissue consisting of a specialized extracellular matrix (ECM) that dominates the bulk of its wet and dry weight. Type II collagen and aggrecan are the main ECM proteins in cartilage. However, little attention has been paid to less abundant molecular components......, especially minor collagens, including type IV, VI, IX, X, XI, XII, XIII, and XIV, etc. Although accounting for only a small fraction of the mature matrix, these minor collagens not only play essential structural roles in the mechanical properties, organization, and shape of articular cartilage, but also...... fulfil specific biological functions. Genetic studies of these minor collagens have revealed that they are associated with multiple connective tissue diseases, especially degenerative joint disease. The progressive destruction of cartilage involves the degradation of matrix constituents including...

  14. Cell-nanofiber-based cartilage tissue engineering using improved cell seeding, growth factor, and bioreactor technologies. (United States)

    Li, Wan-Ju; Jiang, Yi Jen; Tuan, Rocky S


    Biodegradable nanofibrous scaffolds serving as an extracellular matrix substitute have been shown to be applicable for cartilage tissue engineering. However, a key challenge in using nanofibrous scaffolds for tissue engineering is that the small pore size limits the infiltration of cells, which may result in uneven cell distribution throughout the scaffold. This study describes an effective method of chondrocyte loading into nanofibrous scaffolds, which combines cell seeding, mixing, and centrifugation to form homogeneous, packed cell-nanofiber composites (CNCs). When the effects of different growth factors are compared, CNCs cultured in medium containing a combination of insulin-like growth factor-1 and transforming growth factor-beta1 express the highest mRNA levels of collagen type II and aggrecan. Radiolabeling analyses confirm the effect on collagen and sulfated-glycosaminoglycans (sGAG) production. Histology reveals chondrocytes with typical morphology embedded in lacuna-like space throughout the entire structure of the CNC. Upon culturing using a rotary wall vessel bioreactor, CNCs develop into a smooth, glossy cartilage-like tissue, compared to a rough-surface tissue when maintained in a static environment. Bioreactor-grown cartilage constructs produce more total collagen and sGAG, resulting in greater gain in net tissue weight, as well as express cartilage-associated genes, including collagen types II and IX, cartilage oligomeric matrix protein, and aggrecan. In addition, dynamic culture enhances the mechanical property of the engineered cartilage. Taken together, these results indicate the applicability of nanofibrous scaffolds, combined with efficient cell loading and bioreactor technology, for cell-based cartilage tissue engineering.

  15. Surface and mineral structure of ferrihydrite

    NARCIS (Netherlands)

    Hiemstra, T.


    Ferrihydrite (Fh) is an yet enigmatic nano Fe(III)-oxide material, omnipresent in nature that can bind ions in large quantities, regulating bioavailability and ion mobility. Although extensively studied, to date no proper view exists on the surface structure and composition, while it is of vital

  16. Melamine structures on the Au(111) surface

    NARCIS (Netherlands)

    Silly, Fabien; Shaw, Adam Q.; Castell, Martin R.; Briggs, G. A. D.; Mura, Manuela; Martsinovich, Natalia; Kantorovich, Lev


    We report on a joint experimental and theoretical study of the ordered structures of melamine molecules formed on the Au(111)-(22 x root 3) surface. Scanning tunneling microscopy (STM) images taken under UHV conditions reveal two distinct monolayers one of which has never been reported before on

  17. Multiresolution Computation of Conformal Structures of Surfaces

    Directory of Open Access Journals (Sweden)

    Xianfeng Gu


    Full Text Available An efficient multiresolution method to compute global conformal structures of nonzero genus triangle meshes is introduced. The homology, cohomology groups of meshes are computed explicitly, then a basis of harmonic one forms and a basis of holomorphic one forms are constructed. A progressive mesh is generated to represent the original surface at different resolutions. The conformal structure is computed for the coarse level first, then used as the estimation for that of the finer level, by using conjugate gradient method it can be refined to the conformal structure of the finer level.

  18. Cartilage Engineering and Microgravity (United States)

    Toffanin, R.; Bader, A.; Cogoli, A.; Carda, C.; Fantazzini, P.; Garrido, L.; Gomez, S.; Hall, L.; Martin, I.; Murano, E.; Poncelet, D.; Pörtner, R.; Hoffmann, F.; Roekaerts, D.; Ronney, P.; Triebel, W.; Tummers, M.


    The complex effects of mechanical forces and growth factors on articular cartilage development still need to be investigated in order to identify optimal conditions for articular cartilage repair. Strictly controlled in vitro studies under modelled or space microgravity conditions can improve our understanding of the fundamental role of gravity in articular cartilage development. The main objective of this Topical Team is to use modelled microgravity as a tool to elucidate the fundamental science of cartilage regeneration. Particular attention is, therefore, given to the effects of physical forces under altered gravitational conditions, applied using controlled bioreactor systems, on cell metabolism, cell differentiation and tissue development. Specific attention is also directed toward the potential advantages of using magnetic resonance methods for the non-destructive characterisation of scaffolds, chondrocytes-polymer constructs and tissue engineered cartilage.

  19. Mesenchymal Stem Cells for Cartilage Regeneration of TMJ Osteoarthritis


    Dixin Cui; Hongyu Li; Xin Xu; Ling Ye; Xuedong Zhou; Liwei Zheng; Yachuan Zhou


    Temporomandibular joint osteoarthritis (TMJ OA) is a degenerative disease, characterized by progressive cartilage degradation, subchondral bone remodeling, synovitis, and chronic pain. Due to the limited self-healing capacity in condylar cartilage, traditional clinical treatments have limited symptom-modifying and structure-modifying effects to restore impaired cartilage as well as other TMJ tissues. In recent years, stem cell-based therapy has raised much attention as an alternative approach...

  20. Cartilage Tissue Engineering: the effect of different biomaterials, cell types and culture methods

    NARCIS (Netherlands)

    W.J.C.M. Marijnissen (Willem)


    textabstractChapter 1 outlines the normal structure and composition of articular cartilage and the inefficient spontaneous healing response after focal damage. Current surgical treatment options are briefly discussed and tissue engineering techniques for the repair of articular cartilage defects

  1. [Physiology and pathology of the epiphyseal cartilage (author's transl)]. (United States)

    Cotta, H; Rauterberg, K


    Knowledge of the physiology of the epiphyseal cartilage, respectively epiphyseal plate, is essential for an understanding of defective growth and abnormal modeling of the long bones. The epiphyseal cartilage develops from the embryonal, cartilaginous long bone structure. The histology of the epiphyseal cartilage is characterised by definable zones representing the individual differentiation steps from the reformation of cartilage to chondrolysis. Modeling of the ends of the long bones is also influenced by a transversal and longitudinal direction of growth in the epiphyseal cartilage. The intercellular substance mainly contains collagin, proteoglycanes and non-collagenic proteins. These macromolecules are compounded by means of physicochemical bonds and are responsible for the special mechanical qualities of the hyaline cartilage. The process of mineralisation at the base of the epiphyseal cartilage is an essential differentiating step for the ossification processes which take place in the metaphysis. Two pathogenetic principles at the epiphyseal cartilage appear to be important for the defective growth of the long bones. On the one hand, the flowing equilibrium between the differentiation steps of cartilage reformation, transformation of the hyaline cartilage into a mineralised cartilaginous tissue and chondrolysis is changed, whereas on the other hand the turnover of these differentiation steps is retarded or accelerated.

  2. Surface structure of oriented PET films

    CERN Document Server

    Kirov, K


    crystallinity and the level of molecular orientation of the polymer are highest at the film surface and gradually decrease away from it. The same trend for an increase in structural order nearer the film surface was observed in a series of PET films drawn uniaxially in laboratory conditions. The observed strong dependence of stratification in the oriented films on drawing ratio, lead to the conclusion, that the structural gradients arise as a result of viscous flow. The molecular mechanism of stratification is discussed and leads to the idea of enhanced chain mobility at the PET film surface. The idea is in line with recent studies showing a depression of the glass transition temperature of free polymer surfaces. In addition, the results on structure formation in PET films during drawing, give support to the existing view that polymer crystallisation is assisted by a spinodal-decomposition nucleation process. Polymer films are widely used as substrates in nano-composite materials and therefore have to possess...

  3. New Techniques for Cartilage Magnetic Resonance Imaging Relaxation Time Analysis: Texture Analysis of Flattened Cartilage and Localized Intra- and Inter-subject Comparisons


    Carballido-Gamio, Julio; Link, Thomas M.; Majumdar, Sharmila


    MR relaxation time measurements of knee cartilage have shown potential to characterize knee osteoarthritis (OA). In this work, techniques that allow localized intra- and inter-subject comparisons of cartilage relaxation times, as well as cartilage flattening for texture analysis parallel and perpendicular to the natural cartilage layers, are presented. The localized comparisons are based on the registration of bone structures and the assignment of relaxation time feature vectors to each point...

  4. Surface electronic structure of rare earth metals

    Energy Technology Data Exchange (ETDEWEB)

    Blyth, R.I.R.; Dhesi, S.S.; Gravil, P.A.; Newstead, K.; Cosso, R.; Cole, R.J.; Patchett, A.J.; Mitrelias, T. (Surface Science Research Centre, Univ. of Liverpool (United Kingdom)); Prince, N.P.; Barrett, S.D. (Surface Science Research Centre, Univ. of Liverpool (United Kingdom) Oliver Lodge Lab., Univ. of Liverpool (United Kingdom))


    Angle-resolved UV photoemission has been used to investigate the electronic structure of the (0001) surfaces of scandium, yttrium, praseodymium and gadolinium. Off-normal emission spectra were recorded with high angular resolution, enabling detailed mapping of the dispersion of valence band features. Yttrium and gadolinium show similar results to published data from Ho(0001), suggesting minimal 4f influence in the lanthanide bandstructures. Differences seen on praseodymium and scandium may be due to 4f-derived states and surface states respectively. (orig.).

  5. In Vitro Models For Cell-Based Cartilage Regeneration

    NARCIS (Netherlands)

    M.L. de Vries-Van Melle (Marloes)


    markdownabstract__Abstract__ Covering the ends of the long bones in articular joints, cartilage allows smooth, gliding movement of the joints and distributes load evenly across the joint surface. Lesions in the articular cartilage are a major cause of discomfort and disability, especially in

  6. Cartilage Tissue Engineering: What Have We Learned in Practice? (United States)

    Doran, Pauline M


    Many technologies that underpin tissue engineering as a research field were developed with the aim of producing functional human cartilage in vitro. Much of our practical experience with three-dimensional cultures, tissue bioreactors, scaffold materials, stem cells, and differentiation protocols was gained using cartilage as a model system. Despite these advances, however, generation of engineered cartilage matrix with the composition, structure, and mechanical properties of mature articular cartilage has not yet been achieved. Currently, the major obstacles to synthesis of clinically useful cartilage constructs are our inability to control differentiation to the extent needed, and the failure of engineered and host tissues to integrate after construct implantation. The aim of this chapter is to distil from the large available body of literature the seminal approaches and experimental techniques developed for cartilage tissue engineering and to identify those specific areas requiring further research effort.

  7. Electronic Structure of Regular Bacterial Surface Layers (United States)

    Vyalikh, Denis V.; Danzenbächer, Steffen; Mertig, Michael; Kirchner, Alexander; Pompe, Wolfgang; Dedkov, Yuriy S.; Molodtsov, Serguei L.


    We report photoemission and near-edge x-ray absorption fine structure measurements of the occupied and unoccupied valence electronic states of the regular surface layer of Bacillus sphaericus, which is widely used as the protein template for the fabrication of metallic nanostructures. The two-dimensional protein crystal shows a semiconductorlike behavior with a gap value of ˜3.0 eV and the Fermi energy close to the bottom of the lowest unoccupied molecular orbital. We anticipate that these results will open up new possibilities for the electric addressability of biotemplated low-dimensional hybrid structures.

  8. Surface Structure of Acrylate Polymer Adhesives. (United States)

    Roy, Sandra; Freiberg, Stephan; Leblanc, Claude; Hore, Dennis K


    Total internal reflection infrared (IR) absorption and visible-IR sum-frequency spectroscopies were used to study the role of acrylic acid in the evolution of surface structure in a poly(butyl acrylate)-based pressure-sensitive adhesive during the drying process. By monitoring these spectral responses and calculating the heterospectral correlation coefficients, we established that acrylic acid alters the nature of the molecular interactions at the surface. In the absence of acrylic acid, butyl acrylate orientation is driven by the packing of the polymer as the water evaporates. When acrylic acid is present, a rapid ordering of the copolymer takes place as a result of favorable hydrogen-bonding interactions with the surface.

  9. Laser radiation effect on chondrocytes and intercellular matrix of costal and articular cartilage impregnated with magnetite nanoparticles. (United States)

    Soshnikova, Yulia M; Shekhter, Anatoly B; Baum, Olga I; Shcherbakov, Evgeniy M; Omelchenko, Alexander I; Lunin, Valeriy V; Sobol, Emil N


    Magnetic nanoparticles with the ability to absorb laser radiation are the perspective agents for the early diagnostics and laser therapy of degenerative cartilage. The effect of starch stabilized magnetite nanoparticles (SSNPs) on the cartilage structure components has never been studied before. The aim of the work is to establish the Erbium:glass laser effect on costal and articular cartilage impregnated with SSNPs. Porcine articular and costal cartilage disks (2.0 mm in diameter and 1.5-2 mm in thickness) were impregnated with SSNPs and irradiated using a 1.56 μm laser in therapeutic laser setting. The one sample group underwent the second irradiation after the SSNPs impregnation. The samples were analyzed by the means of histology, histochemistry and transmission electron microscopy (TEM) to reveal the alterations of cells, glycosaminoglycans and collagen network. The irradiated cartilage demonstrates the higher content of cell alterations than the intact one due to the heat and mechanical affection in the course of laser irradiation. However the alterations are localized at the areas near the irradiated surfaces and not dramatic. The impregnation of SSNPs does not cause any additional cell alterations. For both costal and articular cartilage the matrix alterations of irradiated samples are not critical: there is the slight decrease in acid proteoglycan content at the irradiated areas while the collagen network is not altered. Distribution and localization of impregnated SSNPs is described: agglomerates of 150-230 nm are observed located at the borders between matrix and cell lacunas of articular cartilage; SSNPs of 15-45 nm are found in the collagen network of costal cartilage. It was shown that SSNPs do not appreciably affect the structural components of both articular and costal cartilage and can be safely used for the laser diagnostics and therapy. The area of structural alterations is diffuse and local as the result of the mechanical and heat

  10. Human elastic cartilage engineering from cartilage progenitor cells using rotating wall vessel bioreactor. (United States)

    Takebe, T; Kobayashi, S; Kan, H; Suzuki, H; Yabuki, Y; Mizuno, M; Adegawa, T; Yoshioka, T; Tanaka, J; Maegawa, J; Taniguchi, H


    Transplantation of bioengineered elastic cartilage is considered to be a promising approach for patients with craniofacial defects. We have previously shown that human ear perichondrium harbors a population of cartilage progenitor cells (CPCs). The aim of this study was to examine the use of a rotating wall vessel (RWV) bioreactor for CPCs to engineer 3-D elastic cartilage in vitro. Human CPCs isolated from ear perichondrium were expanded and differentiated into chondrocytes under 2-D culture conditions. Fully differentiated CPCs were seeded into recently developed pC-HAp/ChS (porous material consisted of collagen, hydroxyapatite, and chondroitinsulfate) scaffolds and 3-D cultivated utilizing a RWV bioreactor. 3-D engineered constructs appeared shiny with a yellowish, cartilage-like morphology. The shape of the molded scaffold was maintained after RWV cultivation. Hematoxylin and eosin staining showed engraftment of CPCs inside pC-HAp/ChS. Alcian blue and Elastica Van Gieson staining showed of proteoglycan and elastic fibers, which are unique extracellular matrices of elastic cartilage. Thus, human CPCs formed elastic cartilage-like tissue after 3-D cultivation in a RWV bioreactor. These techniques may assist future efforts to reconstruct complicate structures composed of elastic cartilage in vitro. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Role of Chondrocytes in Cartilage Formation, Progression of Osteoarthritis and Cartilage Regeneration

    Directory of Open Access Journals (Sweden)

    Hemanth Akkiraju


    Full Text Available Articular cartilage (AC covers the diarthrodial joints and is responsible for the mechanical distribution of loads across the joints. The majority of its structure and function is controlled by chondrocytes that regulate Extracellular Matrix (ECM turnover and maintain tissue homeostasis. Imbalance in their function leads to degenerative diseases like Osteoarthritis (OA. OA is characterized by cartilage degradation, osteophyte formation and stiffening of joints. Cartilage degeneration is a consequence of chondrocyte hypertrophy along with the expression of proteolytic enzymes. Matrix Metalloproteinases (MMPs and A Disintegrin and Metalloproteinase with Thrombospondin Motifs (ADAMTS are an example of these enzymes that degrade the ECM. Signaling cascades involved in limb patterning and cartilage repair play a role in OA progression. However, the regulation of these remains to be elucidated. Further the role of stem cells and mature chondrocytes in OA progression is unclear. The progress in cell based therapies that utilize Mesenchymal Stem Cell (MSC infusion for cartilage repair may lead to new therapeutics in the long term. However, many questions are unanswered such as the efficacy of MSCs usage in therapy. This review focuses on the role of chondrocytes in cartilage formation and the progression of OA. Moreover, it summarizes possible alternative therapeutic approaches using MSC infusion for cartilage restoration.

  12. From gristle to chondrocyte transplantation: treatment of cartilage injuries. (United States)

    Lindahl, Anders


    This review addresses the progress in cartilage repair technology over the decades with an emphasis on cartilage regeneration with cell therapy. The most abundant cartilage is the hyaline cartilage that covers the surface of our joints and, due to avascularity, this tissue is unable to repair itself. The cartilage degeneration seen in osteoarthritis causes patient suffering and is a huge burden to society. The surgical approach to cartilage repair was non-existing until the 1950s when new surgical techniques emerged. The use of cultured cells for cell therapy started as experimental studies in the 1970s that developed over the years to a clinical application in 1994 with the introduction of the autologous chondrocyte transplantation technique (ACT). The technology is now spread worldwide and has been further refined by combining arthroscopic techniques with cells cultured on matrix (MACI technology). The non-regenerating hypothesis of cartilage has been revisited and we are now able to demonstrate cell divisions and presence of stem-cell niches in the joint. Furthermore, cartilage derived from human embryonic stem cells and induced pluripotent stem cells could be the base for new broader cell treatments for cartilage injuries and the future technology base for prevention and cure of osteoarthritis. © 2015 The Author(s).

  13. Structural and spectroscopic studies of surfaces

    CERN Document Server

    Laitenberger, P


    and on a 10ML thick Ar spacer layer, a remarkable substrate dependence is revealed. A new STM-based technique for fabricating simple metal-structures with dimensions in the 10-100nm regime which are partially electrically isolated from their environment was developed in collaboration with Dr. L. A. Silva. This technique employs the STM tip as a mechanical nanofabrication tool to machine gaps into a thin metallic film deposited on an insulating substrate, which laterally confine and electrically isolate the desired metal regions. Several metal structures, such as nanoscale wires and pads, were successfully created. Finally, the conceptual basis and present stage of construction of a new surface analytical tool, the Scanning Probe Energy Loss Spectrometer (SPELS), is discussed. The SPELS offers the exciting prospect of collecting structural as well as spectroscopic information with a spatial resolution of a few nanometres. Once successfully developed, it will be ideally suited for spectroscopic studies of nanos...

  14. Architectural Surfaces and Structures from Circular Arcs

    KAUST Repository

    Shi, Ling


    In recent decades, the popularity of freeform shapes in contemporary architecture poses new challenges to digital design. One of them is the process of rationalization, i.e. to make freeform skins or structures affordable to manufacture, which draws the most attention from geometry researchers. In this thesis, we aim to realize this process with simple geometric primitives, circular arcs. We investigate architectural surfaces and structures consisting of circular arcs. Our focus is lying on how to employ them nicely and repetitively in architectural design, in order to decrease the cost in manufacturing. Firstly, we study Darboux cyclides, which are algebraic surfaces of order ≤ 4. We provide a computational tool to identify all families of circles on a given cyclide based on the spherical model of M ̈obius geometry. Practical ways to design cyclide patches that pass through certain inputs are presented. In particular, certain triples of circle families on Darboux cyclides may be suitably arranged as 3-webs. We provide a complete classification of all possible 3-webs of circles on Darboux cyclides. We then investigate the circular arc snakes, which are smooth sequences of circu- lar arcs. We evolve the snakes such that their curvature, as a function of arc length, remains unchanged. The evolution of snakes is utilized to approximate given surfaces by circular arcs or to generated freeform shapes, and it is realized by a 2-step pro- cess. More interestingly, certain 6-arc snake with boundary constraints can produce a smooth self motion, which can be employed to build flexible structures. Another challenging topic is approximating smooth freeform skins with simple panels. We contribute to this problem area by approximating a negatively-curved 5 surface with a smooth union of rational bilinear patches. We provide a proof for vertex consistency of hyperbolic nets using the CAGD approach of the rational B ́ezier form. Moreover, we use Darboux transformations for the

  15. Neisserial surface lipoproteins: structure, function and biogenesis. (United States)

    Hooda, Yogesh; Shin, Hyejin E; Bateman, Thomas J; Moraes, Trevor F


    The surface of many Gram-negative bacteria contains lipidated protein molecules referred to as surface lipoproteins or SLPs. SLPs play critical roles in host immune evasion, nutrient acquisition and regulation of the bacterial stress response. The focus of this review is on the SLPs present in Neisseria, a genus of bacteria that colonise the mucosal surfaces of animals. Neisseria contains two pathogens of medical interest, namely Neisseria meningitidis and N. gonorrhoeae. Several SLPs have been identified in Neisseria and their study has elucidated key strategies used by these pathogens to survive inside the human body. Herein, we focus on the identification, structure and function of SLPs that have been identified in Neisseria. We also survey the translocation pathways used by these SLPs to reach the cell surface. Specifically, we elaborate on the strategies used by neisserial SLPs to translocate across the outer membrane with an emphasis on Slam, a novel outer membrane protein that has been implicated in SLP biogenesis. Taken together, the study of SLPs in Neisseria illustrates the widespread roles played by this family of proteins in Gram-negative bacteria. © FEMS 2017. All rights reserved. For permissions, please e-mail:

  16. Comparison of equine articular cartilage thickness in various joints. (United States)

    Lee, Hyeon; Kirkland, W Grant; Whitmore, Ryan N; Theis, Kelcie M; Young, Hannah E; Richardson, Ashton J; Jackson, Robert L; Hanson, R Reid


    Thicknesses of fresh equine articular cartilage surfaces from the fetlock, carpal and stifle joints were measured employing a needle probe test. Eighty-seven samples used in measurement were cultivated from fetlock, carpal and stifle joints of 12 deceased within 4 h of death. After approximately three minutes of exposure to air during dissection, all cartilage samples were preserved in a saline solution to keep the articular cartilage hydrated for testing. The thickness was measured on five different spots on the same sample. The thicknesses of the fetlock, carpus and stifle were compared. The articular cartilage of the stifle was thicker than the fetlock and carpus, while the fetlock and the carpus had similar thickness values. The average thickness of the fetlock, carpal and stifle joint are 0.86, 0.87 and 2.1 mm, respectively. They were statistically compared using the Student t-test. The differences on the articular cartilage thicknesses between the fetlock and stifle, and carpus and stifle were "very highly significant" (p fetlock and carpus. Four different surfaces in the fetlock and four in the carpal joint were also compared. Significant differences between each set of the four surfaces were not observed. In the carpus, the difference in thickness between the distal radius and proximal third carpal bone articular cartilage surfaces as well as the proximal radial carpal bone and distal radial carpal bone articular cartilage surfaces were statistically significant.

  17. Mesenchymal Stem Cells for Treating Articular Cartilage Defects and Osteoarthritis. (United States)

    Wang, Yu; Yuan, Mei; Guo, Quan-yi; Lu, Shi-bi; Peng, Jiang


    Articular cartilage damage and osteoarthritis are the most common joint diseases. Joints are prone to damage caused by sports injuries or aging, and such damage regularly progresses to more serious joint disorders, including osteoarthritis, which is a degenerative disease characterized by the thinning and eventual wearing out of articular cartilage, ultimately leading to joint destruction. Osteoarthritis affects millions of people worldwide. Current approaches to repair of articular cartilage damage include mosaicplasty, microfracture, and injection of autologous chondrocytes. These treatments relieve pain and improve joint function, but the long-term results are unsatisfactory. The long-term success of cartilage repair depends on development of regenerative methodologies that restore articular cartilage to a near-native state. Two promising approaches are (i) implantation of engineered constructs of mesenchymal stem cell (MSC)-seeded scaffolds, and (ii) delivery of an appropriate population of MSCs by direct intra-articular injection. MSCs may be used as trophic producers of bioactive factors initiating regenerative activities in a defective joint. Current challenges in MSC therapy are the need to overcome current limitations in cartilage cell purity and to in vitro engineer tissue structures exhibiting the required biomechanical properties. This review outlines the current status of MSCs used in cartilage tissue engineering and in cell therapy seeking to repair articular cartilage defects and related problems. MSC-based technologies show promise when used to repair cartilage defects in joints.

  18. Electronic structure and catalysis on metal surfaces. (United States)

    Greeley, Jeff; Nørskov, Jens K; Mavrikakis, Manos


    The powerful computational resources available to scientists today, together with recent improvements in electronic structure calculation algorithms, are providing important new tools for researchers in the fields of surface science and catalysis. In this review, we discuss first principles calculations that are now capable of providing qualitative and, in many cases, quantitative insights into surface chemistry. The calculations can aid in the establishment of chemisorption trends across the transition metals, in the characterization of reaction pathways on individual metals, and in the design of novel catalysts. First principles studies provide an excellent fundamental complement to experimental investigations of the above phenomena and can often allow the elucidation of important mechanistic details that would be difficult, if not impossible, to determine from experiments alone.

  19. Structure and thermodynamics of surface recognition

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, G.


    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Interactions of the surface glycoprotein, gp120, with the receptors of host cells define the pathogenesis of HIV-1, the virus that causes AIDS. gp120 is made of several disulfide-bridged loops--the amino acid sequences of some of these loops are fairly conserved whereas the rest are variable. The third variable (V3) loop has been the target of vaccine design for quite some time since this loop is involved in various steps of viral pathogenesis. However, this loop also happens to be the most variable one. The authors have carried out structural and immunological studies to determine the sequence-structure-antigenicity correlations of the HIV-1 V3 loops. This resulted in the identification of a secondary structure at the tip of the V3 loop that remains invariant in spite of the sequence variation. The authors designed a multi-valent V3-based antigen that presents multiple copies of the same tip element several times in the same structure. During the course of this project, they realized that the protective epitopes of gp120 should be judged in the context of the native structure. Therefore, the authors developed a method to obtain a model of gp120 that is consistent with all the immunology and virology data. This model is useful in choosing or designing gp120 subdomains for vaccine development.

  20. Repair of osteochondral defects with allogeneic tissue engineered cartilage implants. (United States)

    Schreiber, R E; Ilten-Kirby, B M; Dunkelman, N S; Symons, K T; Rekettye, L M; Willoughby, J; Ratcliffe, A


    The objective of this study was to evaluate the effect of allogeneic tissue engineered cartilage implants on healing of osteochondral defects. Rabbit chondrocytes were cultured in monolayer, then seeded onto biodegradable, three-dimensional polyglycolic acid meshes. Cartilage constructs were cultured hydrodynamically to yield tissue with relatively more (mature) or less (immature) hyalinelike cartilage, as compared with adult rabbit articular cartilage. Osteochondral defects in the patellar grooves of both stifle joints either were left untreated or implanted with allogeneic tissue engineered cartilage. Histologic samples from in and around the defect sites were examined 3, 6, 9, and 12, and 24 months after surgery. By 9 months after surgery, defects sites treated with cartilage implants contained significantly greater amounts of hyalinelike cartilage with high levels of proteoglycan, and had a smooth, nonfibrillated articular surface as compared to untreated defects. In contrast, the repair tissue formed in untreated defects had fibrillated articular surfaces, significant amounts of fibrocartilage, and negligible proteoglycan. These differences between treated and untreated defects persisted through 24 months after surgery. The results of this study suggest that the treatment of osteochondral lesions with allogenic tissue engineered cartilage implants may lead to superior repair tissue than that found in untreated osteochondral lesions.

  1. Effect of disulfide bonding and multimerization on proteoglycan 4's cartilage boundary lubricating ability and adsorption. (United States)

    Abubacker, Saleem; Ponjevic, Dragana; Ham, Hyun O; Messersmith, Phillip B; Matyas, John R; Schmidt, Tannin A


    The objectives of this study were to assess the cartilage boundary lubricating ability of (1) nonreduced (NR) disulfide-bonded proteoglycan 4 (PRG4) multimers versus PRG4 monomers and (2) NR versus reduced and alkylated (R/A) PRG4 monomers and to assess (3) the ability of NR PRG4 multimers versus monomers to adsorb to an articular cartilage surface. PRG4 was separated into two preparations, PRG4 multimer enriched (PRG4Multi+) and PRG4 multimer deficient (PRG4Multi-), using size exclusion chromatography (SEC) and characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The cartilage boundary lubricating ability of PRG4Multi+ and PRG4Multi- was compared at a physiological concentration (450 μg/mL) and assessed over a range of concentrations (45, 150, and 450 μg/mL). R/A and NR PRG4Multi- were evaluated at 450 μg/mL. Immunohistochemistry with anti-PRG4 antibody 4D6 was performed to visualize the adsorption of PRG4 preparations to the surface of articular cartilage explants. Separation into enriched populations of PRG4Multi+ and PRG4Multi- was achieved using SEC and was confirmed by SDS-PAGE. PRG4Multi+ and PRG4Multi- both functioned as effective friction-reducing cartilage boundary lubricants at 450 μg/mL, with PRG4Multi+ being more effective than PRG4Multi-. PRG4Multi+ lubricated in a dose-dependent manner, however, PRG4Multi- did not. R/A PRG4Multi- lubricated similar to NR PRG4Multi-. PRG4-containing solutions showed 4D6 immunoreactivity at the articular surface; the immunoreactive intensity of PRG4Multi+ appeared to be similar to SF, whereas PRG4Multi- appeared to have less intensity. These results demonstrate that the intermolecular disulfide-bonded multimeric structure of PRG4 is important for its ability to adsorb to a cartilage surface and function as a boundary lubricant. These findings contribute to a greater understanding of the molecular basis of cartilage boundary lubrication of PRG4. Elucidating the PRG4 structure

  2. Electronic structure of bacterial surface protein layers (United States)

    Maslyuk, Volodymyr V.; Mertig, Ingrid; Bredow, Thomas; Mertig, Michael; Vyalikh, Denis V.; Molodtsov, Serguei L.


    We report an approach for the calculation of the electronic density of states of the dried two-dimensional crystalline surface protein layer ( S layer) of the bacterium Bacillus sphaericus NCTC 9602. The proposed model is based on the consideration of individual amino acids in the corresponding conformation of the peptide chain which additively contribute to the electronic structure of the entire protein complex. The derived results agree well with the experimental data obtained by means of photoemission (PE), resonant PE, and near-edge x-ray absorption spectroscopy.

  3. Nanoscale surface topographies for structural colors

    DEFF Research Database (Denmark)

    Clausen, Jeppe Sandvik

    The thesis describes and demonstrates the possibilities for utilization of structural colors in mass fabricated plastic products as replacement for or in combination with pigments and inks. The motivation is the possible advantages related to re-cycling and re-use of plastic by limiting the number...... of materials in a given plastic part. Also, the reduction of process steps and materials leads to a reduction of the fabrication costs. In the thesis only surfaces, which may be fabricated using replication based methods, such as injection molding, are considered. Nanostructures with sizes comparable......-polymer interface is suppressed. This improves the ability to see through a clear plastic in the presence of specular reflection. The tapered nanostructures are also utilized to enhance the chroma of pigmented polymers. Larger tapered structures fabricated in a similar manor are shown to work as color filters...

  4. Experimentally induced cartilage degeneration treated by pulsed electromagnetic field stimulation; an in vitro study on bovine cartilage. (United States)

    Veronesi, Francesca; Fini, Milena; Giavaresi, Gianluca; Ongaro, Alessia; De Mattei, Monica; Pellati, Agnese; Setti, Stefania; Tschon, Matilde


    Osteoarthritis (OA) is the final result of progressive alterations to articular cartilage structure, composition and cellularity, followed by an increase in the concentration of pro-inflammatory cytokines in joint synovial fluid. Even though the effect of pulsed electromagnetic field (PEMF) stimulation in counteracting OA progression and inflammation is of increasing interest, because of its anabolic and anti-inflammatory properties, the present study aimed to improve the knowledge on cartilage extracellular matrix (ECM) and chondrocyte changes related to the exposure of PEMF, from a histological and histomorphometric point of view. An in vitro OA model was realized, culturing bovine cartilage explants with a high dose of interleukin 1β (IL1β, 50 ng/ml) at different experimental times (24 h, and 7 and 21 days). The effects of PEMFs (75 Hz, 1.5 mT) were evaluated in cartilage explants treated with IL1β or not (control), in terms of cartilage structure, cellularity and proteoglycans, glycosaminoglycans, collagen II and transforming growth factor β1 synthesis by using histology, histomorphometry and immunohistochemistry. Making a comparison with control cartilage, IL1β-treated explants showed a decrease in cartilage matrix, structure and cellularity parameters. PEMFs were able to counteract the progression of OA acting on both cartilage cellularity and ECM in cartilage previously treated with IL1β. Normal distribution (Kolmogroc-Smirnov test) and homoscedasticity (Levene test) of data were verified, then, the non-parametric Kruskal Wallis test followed by Mann-Whiteny U test for pairwise comparisons were performed. The p-value was adjusted according to the Dunn-Sidak correction. These results, obtained by culturing and treating cartilage explants from two different joints, confirmed that PEMF stimulation can be used as adjuvant therapy to preserve cartilage from detrimental effects of high inflammatory cytokine levels during OA.

  5. Transforming growth factor β-induced superficial zone protein accumulation in the surface zone of articular cartilage is dependent on the cytoskeleton. (United States)

    McNary, Sean M; Athanasiou, Kyriacos A; Reddi, A Hari


    The phenotype of articular chondrocytes is dependent on the cytoskeleton, specifically the actin microfilament architecture. Articular chondrocytes in monolayer culture undergo dedifferentiation and assume a fibroblastic phenotype. This process can be reversed by altering the actin cytoskeleton by treatment with cytochalasin. Whereas dedifferentiation has been studied on chondrocytes isolated from the whole cartilage, the effects of cytoskeletal alteration on specific zones of cells such as superficial zone chondrocytes are not known. Chondrocytes from the superficial zone secrete superficial zone protein (SZP), a lubricating proteoglycan that reduces the coefficient of friction of articular cartilage. A better understanding of this phenomenon may be useful in elucidating chondrocyte dedifferentiation in monolayer and accumulation of the cartilage lubricant SZP, with an eye toward tissue engineering functional articular cartilage. In this investigation, the effects of cytoskeletal modulation on the ability of superficial zone chondrocytes to secrete SZP were examined. Primary superficial zone chondrocytes were cultured in monolayer and treated with a combination of cytoskeleton modifying reagents and transforming growth factor β (TGFβ) 1, a critical regulator of SZP production. Whereas cytochalasin D maintains the articular chondrocyte phenotype, the hallmark of the superficial zone chondrocyte, SZP, was inhibited in the presence of TGFβ1. A decrease in TGFβ1-induced SZP accumulation was also observed when the microtubule cytoskeleton was modified using paclitaxel. These effects of actin and microtubule alteration were confirmed through the application of jasplakinolide and colchicine, respectively. As Rho GTPases regulate actin organization and microtubule polymerization, we hypothesized that the cytoskeleton is critical for TGFβ-induced SZP accumulation. TGFβ-mediated SZP accumulation was inhibited by small molecule inhibitors ML141 (Cdc42), NSC23766 (Rac1

  6. Preliminary investigation of intrinsic UV fluorescence spectroscopic changes associated with proteolytic digestion of bovine articular cartilage (United States)

    Lewis, William; Padilla-Martinez, Juan-Pablo; Ortega-Martinez, Antonio; Franco, Walfre


    Degradation and destruction of articular cartilage is the etiology of osteoarthritis (OA), an entity second only to cardiovascular disease as a cause of disability in the United States. Joint mechanics and cartilage biochemistry are believed to play a role in OA; an optical tool to detect structural and chemical changes in articular cartilage might offer benefit for its early detection and treatment. The objective of the present study was to identify the spectral changes in intrinsic ultraviolet (UV) fluorescence of cartilage that occur after proteolytic digestion of cartilage. Bovine articular cartilage samples were incubated in varying concentrations of collagenase ranging from 10ug/mL up to 5mg/mL for 18 hours at 37°C, a model of OA. Pre- and post-incubation measurements were taken of the UV excitation-emission spectrum of each cartilage sample. Mechanical tests were performed to determine the pre- and post-digestion force/displacement ratio associated with indentation of each sample. Spectral changes in intrinsic cartilage fluorescence and stiffness of the cartilage were associated with proteolytic digestion. In particular, changes in the relative intensity of fluorescence peaks associated with pentosidine crosslinks (330 nm excitation, 390 nm emission) and tryptophan (290 nm excitation, 340 nm emission) were found to correlate with different degrees of cartilage digestion and cartilage stiffness. In principle, it may be possible to use UV fluorescence spectral data for early detection of damage to articular cartilage, and as a surrogate measure for cartilage stiffness.

  7. "Changes in cartilage of rats after treatment with Quinolone and in Magnesium-deficient diet "

    Directory of Open Access Journals (Sweden)

    Shakibaei M


    Full Text Available Ultrastructural changes in immature articular carilage were studied after treatment of 5-weeks-old rats with ofloxacin, a fluoroquinolone, and in magnesium deficiency.We concluded that quinolone-induced arthropathy is probably due to chelation of functionally available magnesium in joint cartilage as magnesium deficiency in joint cartilage could impair chondrocyte-matrix- interaction which is mediated by cation-dependent integrin-receptors of the β1-subfamily. With immuno-histochemical methods using monoclonal and polyclonal antibodies we showed that B1 integrins were expressed in rat joint cartilage. Joint cartilage lesions were detected in ofloxacin-treated and magnesium-deficient rats. Lesions were more pronounced in the quinolone-treated group. Expression of several integrins was reduced in the vicinity of lesions after oral treatment with 2×600 mg ofloxacin/kg body wt for one day. Gross-structural lesions (e.g. cleft formation, unmasked collagen fibres in magnesium deficient rats were very similar but changes in intergrin expression were less pronounced. Alterations observed on the ultrastructural level showed striking similarities in magnesium-deficient rats and in rats treated with single doses of 600 mg ofloxacin per kg body wt.Typical observation were: bundle shaped, electron-dense aggregates on the surface and in the cytoplasm of chondrocytes, detachement of the cell membrance from the matrix and necrotic chondrocytes, reduced synthesis and/or reduced of extracellular matrix and swelling of cell organelles such as mitochondria.The results of this study confirm our previously reported finding that quinolone-induced arthropathy probably is caued by a reduction of functionally available magnesium (ionized Mg2+ in cartilage. Furthermore, they provide a basis for aimed studies with human cartilage samples from quinolone-treated patients which might be available postmortal or after hip replacement surgery

  8. Repair of massively defected hemi-joints using demineralized osteoarticular allografts with protected cartilage. (United States)

    Li, Siming; Yang, Xiaohong; Tang, Shenghui; Zhang, Xunmeng; Feng, Zhencheng; Cui, Shuliang


    Surgical replacement of massively defected joints necessarily relies on osteochondral grafts effective to both of bone and cartilage. Demineralized bone matrix (DBM) retains the osteoconductivity but destroys viable chondrocytes in the cartilage portion essential for successful restoration of defected joints. This study prepared osteochondral grafts of DBM with protected cartilage. Protected cartilage portions was characterized by cellular and molecular biology and the grafts were allogenically used for grafting. Protected cartilage showed similar histomorphological structure and protected proteins estimated by total proteins and cartilage specific proteins as in those of fresh controls when DBMs were generated in bone portions. Such grafts were successfully used for simultaneously repair of bone and cartilage in massively defected osteoarticular joints within 16 weeks post-surgery. These results present an allograft with clinical potential for simultaneous restoration of bone and cartilage in defected joints.

  9. Learning surface molecular structures via machine vision (United States)

    Ziatdinov, Maxim; Maksov, Artem; Kalinin, Sergei V.


    Recent advances in high resolution scanning transmission electron and scanning probe microscopies have allowed researchers to perform measurements of materials structural parameters and functional properties in real space with a picometre precision. In many technologically relevant atomic and/or molecular systems, however, the information of interest is distributed spatially in a non-uniform manner and may have a complex multi-dimensional nature. One of the critical issues, therefore, lies in being able to accurately identify (`read out') all the individual building blocks in different atomic/molecular architectures, as well as more complex patterns that these blocks may form, on a scale of hundreds and thousands of individual atomic/molecular units. Here we employ machine vision to read and recognize complex molecular assemblies on surfaces. Specifically, we combine Markov random field model and convolutional neural networks to classify structural and rotational states of all individual building blocks in molecular assembly on the metallic surface visualized in high-resolution scanning tunneling microscopy measurements. We show how the obtained full decoding of the system allows us to directly construct a pair density function—a centerpiece in analysis of disorder-property relationship paradigm—as well as to analyze spatial correlations between multiple order parameters at the nanoscale, and elucidate reaction pathway involving molecular conformation changes. The method represents a significant shift in our way of analyzing atomic and/or molecular resolved microscopic images and can be applied to variety of other microscopic measurements of structural, electronic, and magnetic orders in different condensed matter systems.

  10. Magnetic resonance imaging of the femoral trochlea: evaluation of anatomical landmarks and grading articular cartilage in cadaveric knees

    Energy Technology Data Exchange (ETDEWEB)

    Muhle, Claus [Marienhospital Vechta, Department of Radiology, Vechta (Germany); Veterans Affairs Medical Center, Department of Radiology, San Diego, CA (United States); Mo Ahn, Joong [University of Iowa, Department of Radiology, Iowa, IA (United States); Trudell, Debra; Resnick, Donald [Veterans Affairs Medical Center, Department of Radiology, San Diego, CA (United States)


    The purpose of the study was to define magnetic resonance imaging (MRI) findings before and after contrast medium opacification of the knee joint in cadaveric specimens to demonstrate anatomical landmarks of the trochlear surface in relation to the neighboring structures, and to evaluate different MRI sequences in the detection of cartilage defects of the trochlear and patellar surface of the knee. The morphology and relationship of the proximal trochlear surface to the prefemoral fat of the distal femur were investigated by use of different MR sequences before and after intra-articular gadolinium administration into the knee joint in ten cadaveric knees. Anatomic sections were subsequently obtained. In addition, evaluation of the articular surface of the trochlea was performed by two independent observers. The cartilage surfaces were graded using a 2-point system, and results were compared with macroscopic findings. Of 40 cartilage surfaces evaluated, histopathologic findings showed 9 normal surfaces, 20 containing partial-thickness defects, and 11 containing full-thickness defects. Compared with macroscopic data, sensitivity of MR sequences for the two reviewers was between 17 and 90%; specificity, 75 and 100%; positive predictive value, 75 and 100%; negative predictive value, 20 and 100%, depending on patellar or trochlea lesions. Interobserver variability for the presence of disease, which was measured using the kappa statistic, was dependent on the MR sequence used between 0.243 and 0.851. Magnetic resonance imaging sequences can be used to evaluate the cartilage of the trochlear surface with less accuracy when compared with the results of grading the articular cartilage of the patella. (orig.)


    Directory of Open Access Journals (Sweden)

    S. A. Demkin


    Full Text Available According to current concepts, the influence of autologous platelet-rich plasma (PRP and high molecular hyaluronates (HA on the repair of hyaline cartilage during its inflammatory and degenerative changes has been insufficiently studied yet. The objective of the work was to evaluate the morphological changes in the structure of hyaline cartilage in experimental osteoarthritis after intra-articular injection of PRP and/or HA. Material and methods. The authors used 50 adult rats of Wistar line, weighing 250±2,2 g., distributed into five groups of 10 animals (two control and three experimental groups. An experimental gonarthosis was simulated on four groups of animals. Animals of the first experimental group received intra-articular injection of PRP, the second group – HA, the third – both PRP and HA. Results. No morphological signs of degenerative and inflammatory changes in the first control group were identified. Following osteoarthritis simulation the articular cartilage thinned to 121±20,4 microns (p<0,05 and the volume fraction of chondrocyte decreased to 1,2±0,6% (p<0,05. The authors observed an uneven coloration of collagen fibers with severe tinctorial properties disorder of the articular cartilage matrix. After the RPR introduction the authors observed tickening of the articular cartilage up to 275±18,9 micron (p<0,05 and the volume fraction of chondrocytes up to 18,4±2,0% (p<0,05. The contour of the cartilage surface became smoother with the formation of a cell-free zone. Collagen fibers demonstrated a uniform distribution, tinctorial properties of cartilage matrix in all areas were preserved, no signs of inflammation were noted. After HA introduction the authors observed thickening of the cartilage plate up to 264±21,3 microns (p<0,05 and the volume fraction of chondrocytes up to 11,6±1,2% (p<0,05. The surface of the cartilage featured uneven contours due to multiple areas of pulping. Uneven tinctorial properties of cartilage

  12. Femtosecond laser surface structuring technique for making human enamel and dentin surfaces superwetting (United States)

    Vorobyev, A. Y.; Guo, Chunlei


    It is known that good wettability of enamel and dentin surfaces is a key factor in enhancing adhesion of restorative materials in dentistry. Here, we report on a femtosecond laser surface texturing approach that makes both the enamel and dentine surfaces superwetting. In contrast to the traditional chemical etching that yields random surface structures, this new approach produces engineered surface structures. The surface structure engineered and tested here is an array of femtosecond laser-produced parallel microgrooves that generates a strong capillary force. Due to the powerful capillary action, water is rapidly sucked into this engineered surface structure and spreads even on a vertical surface.

  13. Cartilage Health in Knees Treated with Metal Resurfacing Implants or Untreated Focal Cartilage Lesions: A Preclinical Study in Sheep. (United States)

    Martinez-Carranza, Nicolas; Hultenby, Kjell; Lagerstedt, Anne Sofie; Schupbach, Peter; Berg, Hans E


    Background Full-depth cartilage lesions do not heal and the long-term clinical outcome is uncertain. In the symptomatic middle-aged (35-60 years) patient, treatment with metal implants has been proposed. However, the cartilage health surrounding these implants has not been thoroughly studied. Our objective was to evaluate the health of cartilage opposing and adjacent to metal resurfacing implants. Methods The medial femoral condyle was operated in 9 sheep bilaterally. A metallic resurfacing metallic implant was immediately inserted into an artificially created 7.5 mm defect while on the contralateral knee the defect was left untreated. Euthanasia was performed at 6 months. Six animals, of similar age and study duration, from a previous study were used for comparison in the evaluation of cartilage health adjacent to the implant. Cartilage damage to joint surfaces within the knee, cartilage repair of the defect, and cartilage adjacent to the implant was evaluated macroscopically and microscopically. Results Six animals available for evaluation of cartilage health within the knee showed a varying degree of cartilage damage with no statistical difference between defects treated with implants or left untreated ( P = 0.51; 95% CI -3.7 to 6.5). The cartilage adjacent to the implant (score 0-14; where 14 indicates no damage) remained healthy in these 6 animals showing promising results (averaged 10.5; range 9-11.5, SD 0.95). Cartilage defects did not heal in any case. Conclusion Treatment of a critical size focal lesion with a metal implant is a viable alternative treatment.

  14. Ex vivo culture platform for assessment of cartilage repair treatment strategies. (United States)

    Schwab, Andrea; Meeuwsen, Annick; Ehlicke, Franziska; Hansmann, Jan; Mulder, Lars; Smits, Anthal; Walles, Heike; Kock, Linda


    There is a great need for valuable ex vivo models that allow for assessment of cartilage repair strategies to reduce the high number of animal experiments. In this paper we present three studies with our novel ex vivo osteochondral culture platform. It consists of two separated media compartments for cartilage and bone, which better represents the in vivo situation and enables supply of factors specific to the different needs of bone and cartilage. We investigated whether separation of the cartilage and bone compartments and/or culture media results in the maintenance of viability, structural and functional properties of cartilage tissue. Next, we evaluated for how long we can preserve cartilage matrix stability of osteochondral explants during long-term culture over 84 days. Finally, we determined the optimal defect size that does not show spontaneous self-healing in this culture system. It was demonstrated that separated compartments for cartilage and bone in combination with tissue-specific medium allow for long-term culture of osteochondral explants while maintaining cartilage viability, matrix tissue content, structure and mechanical properties for at least 56 days. Furthermore, we could create critical size cartilage defects of different sizes in the model. The osteochondral model represents a valuable preclinical ex vivo tool for studying clinically relevant cartilage therapies, such as cartilage biomaterials, for their regenerative potential, for evaluation of drug and cell therapies, or to study mechanisms of cartilage regeneration. It will undoubtedly reduce the number of animals needed for in vivo testing.

  15. Recent advances in hydrogels for cartilage tissue engineering. (United States)

    Vega, S L; Kwon, M Y; Burdick, J A


    Articular cartilage is a load-bearing tissue that lines the surface of bones in diarthrodial joints. Unfortunately, this avascular tissue has a limited capacity for intrinsic repair. Treatment options for articular cartilage defects include microfracture and arthroplasty; however, these strategies fail to generate tissue that adequately restores damaged cartilage. Limitations of current treatments for cartilage defects have prompted the field of cartilage tissue engineering, which seeks to integrate engineering and biological principles to promote the growth of new cartilage to replace damaged tissue. To date, a wide range of scaffolds and cell sources have emerged with a focus on recapitulating the microenvironments present during development or in adult tissue, in order to induce the formation of cartilaginous constructs with biochemical and mechanical properties of native tissue. Hydrogels have emerged as a promising scaffold due to the wide range of possible properties and the ability to entrap cells within the material. Towards improving cartilage repair, hydrogel design has advanced in recent years to improve their utility. Some of these advances include the development of improved network crosslinking (e.g. double-networks), new techniques to process hydrogels (e.g. 3D printing) and better incorporation of biological signals (e.g. controlled release). This review summarises these innovative approaches to engineer hydrogels towards cartilage repair, with an eye towards eventual clinical translation.

  16. The Influence of Articular Cartilage Thickness Reduction on Meniscus Biomechanics. (United States)

    Łuczkiewicz, Piotr; Daszkiewicz, Karol; Chróścielewski, Jacek; Witkowski, Wojciech; Winklewski, Pawel J


    Evaluation of the biomechanical interaction between meniscus and cartilage in medial compartment knee osteoarthritis. The finite element method was used to simulate knee joint contact mechanics. Three knee models were created on the basis of knee geometry from the Open Knee project. We reduced the thickness of medial cartilages in the intact knee model by approximately 50% to obtain a medial knee osteoarthritis (OA) model. Two variants of medial knee OA model with congruent and incongruent contact surfaces were analysed to investigate the influence of congruency. A nonlinear static analysis for one compressive load case was performed. The focus of the study was the influence of cartilage degeneration on meniscal extrusion and the values of the contact forces and contact areas. In the model with incongruent contact surfaces, we observed maximal compressive stress on the tibial plateau. In this model, the value of medial meniscus external shift was 95.3% greater, while the contact area between the tibial cartilage and medial meniscus was 50% lower than in the congruent contact surfaces model. After the non-uniform reduction of cartilage thickness, the medial meniscus carried only 48.4% of load in the medial compartment in comparison to 71.2% in the healthy knee model. We have shown that the change in articular cartilage geometry may significantly reduce the role of meniscus in load transmission and the contact area between the meniscus and cartilage. Additionally, medial knee OA may increase the risk of meniscal extrusion in the medial compartment of the knee joint.

  17. Lunar surface structural concepts and construction studies (United States)

    Mikulas, Martin

    The topics are presented in viewgraph form and include the following: lunar surface structures construction research areas; lunar crane related disciplines; shortcomings of typical mobile crane in lunar base applications; candidate crane cable suspension systems; NIST six-cable suspension crane; numerical example of natural frequency; the incorporation of two new features for improved performance of the counter-balanced actively-controlled lunar crane; lunar crane pendulum mechanics; simulation results; 1/6 scale lunar crane testbed using GE robot for global manipulation; basic deployable truss approaches; bi-pantograph elevator platform; comparison of elevator platforms; perspective of bi-pantograph beam; bi-pantograph synchronously deployable tower/beam; lunar module off-loading concept; module off-loader concept packaged; starburst deployable precision reflector; 3-ring reflector deployment scheme; cross-section of packaged starburst reflector; and focal point and thickness packaging considerations.


    Energy Technology Data Exchange (ETDEWEB)

    Harris, Alan W.; Drube, Line, E-mail: [German Aerospace Center (DLR) Institute of Planetary Research, Rutherfordstrasse 2, D-12489 Berlin (Germany)


    Knowledge of the surface thermal inertia of an asteroid can provide insight into its surface structure: porous material has a lower thermal inertia than rock. We develop a means to estimate thermal inertia values of asteroids and use it to show that thermal inertia appears to increase with spin period in the case of main-belt asteroids (MBAs). Similar behavior is found on the basis of thermophysical modeling for near-Earth objects (NEOs). We interpret our results in terms of rapidly increasing material density and thermal conductivity with depth, and provide evidence that thermal inertia increases by factors of 10 (MBAs) to 20 (NEOs) within a depth of just 10 cm. Our results are consistent with a very general picture of rapidly changing material properties in the topmost regolith layers of asteroids and have important implications for calculations of the Yarkovsky effect, including its perturbation of the orbits of potentially hazardous objects and those of asteroid family members after the break-up event. Evidence of a rapid increase of thermal inertia with depth is also an important result for studies of the ejecta-enhanced momentum transfer of impacting vehicles (“kinetic impactors”) in planetary defense.

  19. Protein-mediated surface structuring in biomembranes

    Directory of Open Access Journals (Sweden)

    Maggio B.


    Full Text Available The lipids and proteins of biomembranes exhibit highly dissimilar conformations, geometrical shapes, amphipathicity, and thermodynamic properties which constrain their two-dimensional molecular packing, electrostatics, and interaction preferences. This causes inevitable development of large local tensions that frequently relax into phase or compositional immiscibility along lateral and transverse planes of the membrane. On the other hand, these effects constitute the very codes that mediate molecular and structural changes determining and controlling the possibilities for enzymatic activity, apposition and recombination in biomembranes. The presence of proteins constitutes a major perturbing factor for the membrane sculpturing both in terms of its surface topography and dynamics. We will focus on some results from our group within this context and summarize some recent evidence for the active involvement of extrinsic (myelin basic protein, integral (Folch-Lees proteolipid protein and amphitropic (c-Fos and c-Jun proteins, as well as a membrane-active amphitropic phosphohydrolytic enzyme (neutral sphingomyelinase, in the process of lateral segregation and dynamics of phase domains, sculpturing of the surface topography, and the bi-directional modulation of the membrane biochemical reactivity.

  20. Effect of psychological stress on the structure of the temporomandibular joint and the expression of MMP-3 and TIMP-3 in the cartilage in rats. (United States)

    Huang, Xu; Liu, Haixia; Xiao, Peng; Wang, Yan; Zhang, Hongyu


    Our aim was to observe the effects of psychological stress on the structure of the temporomandibular joint (TMJ), and to evaluate the expression of matrix metallopeptidase-3 (MMP-3) and tissue inhibitor of metalloproteinase-3 (TIMP-3) in condylar chondrocytes in rats. The rats were divided into 3 groups of 12 according to the duration of psychological stress: 3 weeks or 6 weeks, and 6 weeks of recovery. A fourth group of 12 rats was used as controls. Each rat was evaluated by the open-field test and the weight measured. The results confirmed psychological stress in 24 of the 36 rats (67%). The tissues of the TMJ were stained with haematoxylin and eosin and pathological changes were studied under a light microscope. MMP-3 and TIMP-3 expression was investigated using the SP kit. The experimental groups showed thinning of articular cartilage, shedding of collagen fibres, cracks in the articular discs, and other structural changes that were aggravated with time, from three weeks to six weeks. The 6-week recovery group showed an improvement in these changes, which indicated the initiation of joint repair. The MMP-3 expression rate correlated with the degree of joint lesion, while the TIMP-3 rate showed an opposite trend and was highest in the 6-week recovery group. Our findings clearly indicate that psychological stress may play an important part in the development of TMJ diseases in rats; further studies should be made to extrapolate the results to other models before clinical use. Copyright © 2014 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  1. Spatially resolved elemental distributions in articular cartilage

    Energy Technology Data Exchange (ETDEWEB)

    Reinert, T. E-mail:; Reibetanz, U.; Vogt, J.; Butz, T.; Werner, A.; Gruender, W


    In this study, the nuclear microprobe technique is employed to analyse the chemistry of joint cartilage in order to correlate internal structures of the collagen network with the elemental distribution. The samples were taken from pig's knee joint. 30 {mu}m thick coronar cross-sections were prepared by means of cryosectioning and freeze-drying. We performed simultaneously particle induced X-ray emission (PIXE), Rutherford backscattering spectrometry (RBS) and elastic recoil detection analysis (ERDA). Thus we obtained spatially resolved distributions of the elements H, C, N, O, P, S, Cl, K and Ca. The main components of the organic matrix are H, C, N and O. It was shown that their relations vary with the cartilage structures. It could be shown that zones with aligned collagen fibrils contain less sulphur and potassium but more chlorine. The higher chlorine concentration is remarkable because newest biochemical studies found that hypochloric acid is involved in cartilage degradation. Furthermore, the calcium distribution is still of great interest. Its correlation to structural changes inside the cartilage is still being discussed. It could be disproved that zones of higher calcium concentration are related to the aligned structures of the collagen network.

  2. Spatially resolved elemental distributions in articular cartilage (United States)

    Reinert, T.; Reibetanz, U.; Vogt, J.; Butz, T.; Werner, A.; Gründer, W.


    In this study, the nuclear microprobe technique is employed to analyse the chemistry of joint cartilage in order to correlate internal structures of the collagen network with the elemental distribution. The samples were taken from pig's knee joint. 30 μm thick coronar cross-sections were prepared by means of cryosectioning and freeze-drying. We performed simultaneously particle induced X-ray emission (PIXE), Rutherford backscattering spectrometry (RBS) and elastic recoil detection analysis (ERDA). Thus we obtained spatially resolved distributions of the elements H, C, N, O, P, S, Cl, K and Ca. The main components of the organic matrix are H, C, N and O. It was shown that their relations vary with the cartilage structures. It could be shown that zones with aligned collagen fibrils contain less sulphur and potassium but more chlorine. The higher chlorine concentration is remarkable because newest biochemical studies found that hypochloric acid is involved in cartilage degradation. Furthermore, the calcium distribution is still of great interest. Its correlation to structural changes inside the cartilage is still being discussed. It could be disproved that zones of higher calcium concentration are related to the aligned structures of the collagen network.

  3. Principles of cartilage repair

    CERN Document Server

    Erggelet, Christoph; Mandelbaum, Bert R


    Cartilage defects affect patients of all age groups. Surgeons, teamdoctors, general practitioners and physiotherapists alike are expected to provide adequate care. Only individual treatment plans combining a well balanced choice of various options will be successful. Background knowledge, operative and non-operative therapies are described in concise chapters: Articular cartilage biology - Diagnostics - Surgical techniques - Symptomatic and alternative medications - Physiotherapy. Diagnostic findings and surgical procedures are generously illustrated by aquarelles and colour photographs. Recommendations for additional reading, description of important clinical scoring systems and a listing of analytic tools are added for further information.

  4. Photoelectron spectroscopy bulk and surface electronic structures

    CERN Document Server

    Suga, Shigemasa


    Photoelectron spectroscopy is now becoming more and more required to investigate electronic structures of various solid materials in the bulk, on surfaces as well as at buried interfaces. The energy resolution was much improved in the last decade down to 1 meV in the low photon energy region. Now this technique is available from a few eV up to 10 keV by use of lasers, electron cyclotron resonance lamps in addition to synchrotron radiation and X-ray tubes. High resolution angle resolved photoelectron spectroscopy (ARPES) is now widely applied to band mapping of materials. It attracts a wide attention from both fundamental science and material engineering. Studies of the dynamics of excited states are feasible by time of flight spectroscopy with fully utilizing the pulse structures of synchrotron radiation as well as lasers including the free electron lasers (FEL). Spin resolved studies also made dramatic progress by using higher efficiency spin detectors and two dimensional spin detectors. Polarization depend...

  5. Culturing functional cartilage tissue under a novel bionic mechanical condition. (United States)

    Sun, Minglin; Lv, Dan; Zhang, Chunqiu; Zhu, Lei


    Bioreactor, which is used for in vitro construction of tissue-engineered cartilage, has been extensively studied by researchers. The growth and development of articular cartilage tissue are affected by biomechanical and biochemical factors, especially mechanical condition. Kinds of mechanical conditions including compressive and shear force, fluid flow, hydrostatic pressure, and tissue deformation, were developed in the past years. However, most mechanical conditions of improved bioreactor involve only one or two external force, which is merely partial for engineering cartilage tissue. No bioreactor which can simulate a normal articular cartilage in terms of structure and function has been reported. Consequently, simulation of bionic mechanical environment of a normal articular cartilage is considered to be the optimal environment for culturing the functional articular cartilage in vitro. Based upon this purpose, we designed a rolling-compression loading bioreactor. It could provide cultures with multi-mechanical stimulations and sufficiently mimic the complex mechanical environment of a normal articular cartilage. We propose that this comprehensive rolling-compression loading bioreactor can enhance the cultivation of functional cartilage constructs in vitro. Copyright © 2010 Elsevier Ltd. All rights reserved.

  6. Biochemical effects on long-term frozen human costal cartilage

    Energy Technology Data Exchange (ETDEWEB)

    Santin, Stefany P.; Martinho Junior, Antonio C.; Yoshito, Daniele; Soares, Fernando A.N.; Mathor, Monica B., E-mail: mathor@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)


    Currently, the progresses on treatment of musculoskeletal diseases with the evolving of artificial implants and the success of tissue transplantation between genetically different individuals have conducted to an increase in radiosterilization. Regarding to tissue transplantation, it is essential to have sterile tissue and many tissue banks use radiosterilization as an effective method to sterilize these tissues. However, high doses of ionizing radiation and the preservation method may induce structural modifications in the tissues, as degradation of structural scaffold, decreasing its mechanical properties. Particularly, cartilage have been preserved in high concentrations of glycerol or deep-frozen at -70 degree C for storage after radiosterilization. Therefore, it is important to study the modifications induced in cartilage by preservation methods and by radiosterilization to determine the appropriated parameters for high quality of human allografts. Costal cartilages were obtained from cadaveric donors and were frozen at -20 degree C for 2 years long in order to compare with previous studies for fresh, deep-frozen and glycerolised cartilages. The mechanical tests were carried out in a universal testing machine until sample failure. According our results, there is no significant statistical difference between stress at break of fresh, long-term - 20 degree C frozen cartilages and deep-frozen cartilage. This early result suggests, regarding to tensile property, that long-term - 20 degree C frozen cartilages corresponds to glycerolised costal cartilages irradiated with 25 kGy or deep-frozen cartilages irradiated with 25 and 50 kGy. Thus, this long-term frozen cartilages may be used for tissue banks, but more studies about effects of ionizing radiation are necessary. (author)

  7. An immunohistochemical study of matrix proteins in the craniofacial cartilage in midterm human fetuses

    Directory of Open Access Journals (Sweden)

    S. Shibata


    Full Text Available Immunohistochemical localization of collagen types I, II, and X, aggrecan, versican, dentin matrix protein (DMP-1, martix extracellular phosphoprotein (MEPE were performed for Meckel’s cartilage, cranial base cartilage, and mandibular condylar cartilage in human midterm fetuses; staining patterns within the condylar cartilage were compared to those within other cartilaginous structures. Mandibular condylar cartilage contained aggrecan; it also had more type I collagen and a thicker hypertrophic cell layer than the other two types of cartilage; these three characteristics are similar to those of the secondary cartilage of rodents. MEPE immunoreactivity was first evident in the cartilage matrix of all types of cartilage in the human fetuses and in Meckel’s cartilage of mice and rats. MEPE immunoreactivity was enhanced in the deep layer of the hypertrophic cell layer and in the cartilaginous core of the bone trabeculae in the primary spongiosa. These results indicated that MEPE is a component of cartilage matrix and may be involved in cartilage mineralization. DMP-1 immunoreactivity first became evident in human bone lacunae walls and canaliculi; this pattern of expression was comparable to the pattern seen in rodents. In addition, chondroid bone was evident in the mandibular (glenoid fossa of the temporal bone, and it had aggrecan, collagen types I and X, MEPE, and DMP-1 immunoreactivity; these findings indicated that chondroid bone in this region has phenotypic expression indicative of both hypertrophic chondrocytes and osteocytes.


    Directory of Open Access Journals (Sweden)

    Ariana Barlič


    Surveys show that the most frequently used surgical methods are mosaicplasty and bonemarrow stimulation with microfracturing. The efficacy of the autologous chondrocyte implantationmethod should be superior to microfracturing on a long run. Especially when(regeneration of the hyaline cartilage instead of fibrous tissue (fibrocartilage is concerned.However, it has not been scientifically proved yet

  9. Evaluation of acoustical parameter sensitivity to age-related and osteoarthritic changes in articular cartilage using 50-MHz ultrasound. (United States)

    Chérin, E; Saïed, A; Laugier, P; Netter, P; Berger, G


    The current study reports the sensitivity of acoustical parameters estimated at high frequency to the osteoarthritic morphological and structural changes in patellar cartilage in rat knees. Osteoarthritis (OA) was induced by a single intra-articular injection of mono-iodo-acetic acid in right knees. OA patellas and their contralateral controls were excised at regular intervals after injection and were examined in vitro with a scanning acoustical microscope operating with a poly(vinylidene di-fluoride) (PVDF) 80-MHz focused transducer. Cartilage thickness was estimated using B-scan images. The quantitative analysis of the radiofrequency signal backscattered by the cartilage was performed using integrated reflection coefficient (IRC) and apparent integrated backscatter (AIB), which were estimated in the 20-60-MHz frequency range. One week after injection, a cartilage thickness decrease was detected (-6%, on average) that preceded the significant hypertrophy (20.1%) that occurred 2 weeks after injection and could be due to tissue repair. From 1 week to 3 weeks after injection, the IRC of OA patellas was significantly lower than that of control patellas. The IRC difference increased with time from -3.3 +/- 2.4 dB at 1 week to -8.4 +/- 1.7 dB at 3 weeks. An AIB decrease was observed with time for both OA and control patellas (-2.9 to -4.2 dB per week). An AIB difference between OA and control patellas was detected from 1 week to 3 weeks after injection. This difference decreased with time. IRC variation reflects a change in acoustical impedance of the superficial layer of the cartilage and could be linked to a change in constituent content and/or to a disruption of fibers of the collagen network that led to the fibrillation of the cartilage surface. AIB variation reflects a change in shape, size and/or density of the scatterers and could be related to changes in the constituent content and in the organization of the matrix in the internal layer of the cartilage. IRC and

  10. Elementary structural building blocks encountered in silicon surface reconstructions

    Energy Technology Data Exchange (ETDEWEB)

    Battaglia, Corsin; Monney, Claude; Didiot, Clement; Schwier, Eike Fabian; Garnier, Michael Gunnar; Aebi, Philipp [Institut de Physique, Universite de Neuchatel, 2000 Neuchatel (Switzerland); Gaal-Nagy, Katalin; Onida, Giovanni [Dipartimento di Fisica and European Theoretical Spectroscopy Facility (ETSF), Universita di Milano, 20133 Milano (Italy)], E-mail:


    Driven by the reduction of dangling bonds and the minimization of surface stress, reconstruction of silicon surfaces leads to a striking diversity of outcomes. Despite this variety even very elaborate structures are generally comprised of a small number of structural building blocks. We here identify important elementary building blocks and discuss their integration into the structural models as well as their impact on the electronic structure of the surface. (topical review)

  11. Image-guided smart laser system for precision implantation of cells in cartilage (United States)

    Katta, Nitesh; Rector, John A.; Gardner, Michael R.; McElroy, Austin B.; Choy, Kevin C.; Crosby, Cody; Zoldan, Janet; Milner, Thomas E.


    State-of-the-art treatment for joint diseases like osteoarthritis focus on articular cartilage repair/regeneration by stem cell implantation therapy. However, the technique is limited by a lack of precision in the physician's imaging and cell deposition toolkit. We describe a novel combination of high-resolution, rapid scan-rate optical coherence tomography (OCT) alongside a short-pulsed nanosecond thulium (Tm) laser for precise cell seeding in cartilage. The superior beam quality of thulium lasers and wavelength of operation 1940 nm offers high volumetric tissue removal rates and minimizes the residual thermal footprint. OCT imaging enables targeted micro-well placement, precise cell deposition, and feature contrast. A bench-top system is constructed using a 15 W, 1940 nm, nanosecond-pulsed Tm fiber laser (500 μJ pulse energy, 100 ns pulse duration, 30kHz repetition rate) for removing tissue, and a swept source laser (1310 ± 70 nm, 100 kHz sweep rate) for OCT imaging, forming a combined Tm/OCT system - a "smart laser knife". OCT assists the smart laser knife user in characterizing cartilage to inform micro-well placement. The Tm laser creates micro-wells (2.35 mm diameter length, 1.5 mm width, 300 μm deep) and micro-incisions (1 mm wide, 200 μm deep) while OCT image-guidance assists and demonstrates this precision cutting and cell deposition with real-time feedback. To test micro-well creation and cell deposition protocol, gelatin phantoms are constructed mimicking cartilage optical properties and physiological structure. Cell viability is then assessed to illustrate the efficacy of the hydrogel deposition. Automated OCT feedback is demonstrated for cutting procedures to avoid important surface/subsurface structures. This bench-top smart laser knife system described here offers a new image-guided approach to precise stem cell seeding that can enhance the efficacy of articular cartilage repair.

  12. Articulation of Native Cartilage Against Different Femoral Component Materials. Oxidized Zirconium Damages Cartilage Less Than Cobalt-Chrome. (United States)

    Vanlommel, Jan; De Corte, Ronny; Luyckx, Jean Philippe; Anderson, Melissa; Labey, Luc; Bellemans, Johan


    Oxidized zirconium (OxZr) is produced by thermally driven oxidization creating an oxidized surface with the properties of a ceramic at the top of the Zr metal substrate. OxZr is much harder and has a lower coefficient of friction than cobalt-chrome (CoCr), both leading to better wear characteristics. We evaluated and compared damage to the cartilage of porcine patella plugs, articulating against OxZr vs CoCr. Our hypothesis was that, owing to its better wear properties, OxZr would damage cartilage less than CoCr. If this is true, OxZr might be a better material for the femoral component during total knee arthroplasty if the patella is not resurfaced. Twenty-one plugs from porcine patellae were prepared and tested in a reciprocating pin-on-disk machine while lubricated with bovine serum and under a constant load. Three different configurations were tested: cartilage-cartilage as the control group, cartilage-OxZr, and cartilage-CoCr. Macroscopic appearance, cartilage thickness, and the modified Mankin score were evaluated after 400,000 wear cycles. The control group showed statistically significant less damage than plugs articulating against both other materials. Cartilage plugs articulating against OxZr were statistically significantly less damaged than those articulating against CoCr. Although replacing cartilage by an implant always leads to deterioration of the cartilage counterface, OxZr results in less damage than CoCr. The use of OxZr might thus be preferable to CoCr in case of total knee arthroplasty without patella resurfacing. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Intra-Articular Injections of Polyphenols Protect Articular Cartilage from Inflammation-Induced Degradation: Suggesting a Potential Role in Cartilage Therapeutics (United States)

    Natarajan, Venkatachalam; Madhan, Balaraman; Tiku, Moti L.


    Arthritic diseases, such as osteoarthritis and rheumatoid arthritis, inflict an enormous health care burden on society. Osteoarthritis, a degenerative joint disease with high prevalence among older people, and rheumatoid arthritis, an autoimmune inflammatory disease, both lead to irreversible structural and functional damage to articular cartilage. The aim of this study was to investigate the effect of polyphenols such as catechin, quercetin, epigallocatechin gallate, and tannic acid, on crosslinking type II collagen and the roles of these agents in managing in vivo articular cartilage degradation. The thermal, enzymatic, and physical stability of bovine articular cartilage explants following polyphenolic treatment were assessed for efficiency. Epigallocatechin gallate and tannic acid-treated explants showed >12 °C increase over native cartilage in thermal stability, thereby confirming cartilage crosslinking. Polyphenol-treated cartilage also showed a significant reduction in the percentage of collagen degradation and the release of glycosaminoglycans against collagenase digestion, indicating the increase physical integrity and resistance of polyphenol crosslinked cartilage to enzymatic digestion. To examine the in vivo cartilage protective effects, polyphenols were injected intra-articularly before (prophylactic) and after (therapeutic) the induction of collagen-induced arthritis in rats. The hind paw volume and histomorphological scoring was done for cartilage damage. The intra-articular injection of epigallocatechin gallate and tannic acid did not significantly influence the time of onset or the intensity of joint inflammation. However, histomorphological scoring of the articular cartilage showed a significant reduction in cartilage degradation in prophylactic- and therapeutic-groups, indicating that intra-articular injections of polyphenols bind to articular cartilage and making it resistant to degradation despite ongoing inflammation. These studies establish

  14. Cartilage extracellular matrix as a biomaterial for cartilage regeneration. (United States)

    Kiyotake, Emi A; Beck, Emily C; Detamore, Michael S


    The extracellular matrix (ECM) of various tissues possesses the model characteristics that biomaterials for tissue engineering strive to mimic; however, owing to the intricate hierarchical nature of the ECM, it has yet to be fully characterized and synthetically fabricated. Cartilage repair remains a challenge because the intrinsic properties that enable its durability and long-lasting function also impede regeneration. In the last decade, cartilage ECM has emerged as a promising biomaterial for regenerating cartilage, partly because of its potentially chondroinductive nature. As this research area of cartilage matrix-based biomaterials emerged, investigators facing similar challenges consequently developed convergent solutions in constructing robust and bioactive scaffolds. This review discusses the challenges, emerging trends, and future directions of cartilage ECM scaffolds, including a comparison between two different forms of cartilage matrix: decellularized cartilage (DCC) and devitalized cartilage (DVC). To overcome the low permeability of cartilage matrix, physical fragmentation greatly enhances decellularization, although the process itself may reduce the chondroinductivity of fabricated scaffolds. The less complex processing of a scaffold composed of DVC, which has not been decellularized, appears to have translational advantages and potential chondroinductive and mechanical advantages over DCC, without detrimental immunogenicity, to ultimately enhance cartilage repair in a clinically relevant way. © 2016 New York Academy of Sciences.

  15. Thickening of the knee joint cartilage in elite weightlifters as a potential adaptation mechanism. (United States)

    Grzelak, Piotr; Domzalski, Marcin; Majos, Agata; Podgórski, Michal; Stefanczyk, Ludomir; Krochmalski, Marek; Polguj, Michal


    Thickening and increase of area of cartilage have been proposed as two alternative mechanisms of cartilage functional adaptation. The latter has been reported in endurance sportsmen. In weightlifters, extreme strain applied to the articular surfaces can result in other forms of adaptation. The aim of this research is to determine whether cartilage thickness is greater in elite weightlifters than in physically inactive men. Weightlifters (13) and 20 controls [age and body mass index (BMI) matched] underwent knee Magnetic Resonance Imaging (MRI). A single sagittal slice of the knee was taken and cartilage thickness was measured in five and six regions of the medial and lateral femoral condyles, respectively. The analyzed segments represented weight-bearing and nonweight-bearing regions. The tibia cartilage in the weight-bearing area was also measured. The time of training onset and its duration in the weightlifter group were recorded. The cartilage was found to be significantly thicker in weightlifters in most of the analyzed regions. The distribution of cartilage thickness on the medial and lateral femoral condyles was similar in both groups. The duration of training was not associated with cartilage thickness, but the time of training onset correlated inversely with cartilage thickness. It is possible that in high-strain sports, joint cartilage can undergo functional adaptation by thickening. Thus, mechanical loading history could exert a postnatal influence on cartilage morphology. © 2014 Wiley Periodicals, Inc.

  16. Label-free characterization of articular cartilage in osteoarthritis model mice by Raman spectroscopy (United States)

    Oshima, Yusuke; Akehi, Mayu; Kiyomatsu, Hiroshi; Miura, Hiromasa


    Osteoarthritis (OA) is very common joint disease in the aging population. Main symptom of OA is accompanied by degenerative changes of articular cartilage. Cartilage contains mostly type II collagen and proteoglycans, so it is difficult to access the quality and morphology of cartilage tissue in situ by conventional diagnostic tools (X-ray, MRI and echography) directly or indirectly. Raman spectroscopy is a label-free technique which enables to analyze molecular composition in degenerative cartilage. In this study, we generated an animal OA model surgically induced by knee joint instability, and the femurs were harvested at two weeks after the surgery. We performed Raman spectroscopic analysis for the articular cartilage of distal femurs in OA side and unaffected side in each mouse. In the result, there is no gross findings in the surface of the articular cartilage in OA. On the other hand, Raman spectral data of the articular cartilage showed drastic changes in comparison between OA and control side. The major finding of this study is that the relative intensity of phosphate band (960 cm-1) increases in the degenerative cartilage. This may be the result of exposure of subchondral bone due to thinning of the cartilage layer. In conclusion, Raman spectroscopic technique is sufficient to characterize articular cartilage in OA as a pilot study for Raman application in cartilage degeneration and regeneration using animal models and human subjects.

  17. Advances in cartilage tissue engineering : in vitro

    NARCIS (Netherlands)

    E.W. Mandl (Erik)


    textabstractWithin the body three subtypes of cartilage can be distinguished: hyaline cartilage, elastic cartilage and fibrocartilage. Hyaline cartilage is the predominant subtype and is mainly located in articular joints and in less extent in the nasal septum and cricoid. Elastic cartilage can be

  18. Fourier-transform infrared anisotropy in cross and parallel sections of tendon and articular cartilage

    Directory of Open Access Journals (Sweden)

    Bidthanapally Aruna


    Full Text Available Abstract Background Fourier Transform Infrared Imaging (FTIRI is used to investigate the amide anisotropies at different surfaces of a three-dimensional cartilage or tendon block. With the change in the polarization state of the incident infrared light, the resulting anisotropic behavior of the tissue structure is described here. Methods Thin sections (6 μm thick were obtained from three different surfaces of the canine tissue blocks and imaged at 6.25 μm pixel resolution. For each section, infrared imaging experiments were repeated thirteen times with the identical parameters except a 15° increment of the analyzer's angle in the 0° – 180° angular space. The anisotropies of amide I and amide II components were studied in order to probe the orientation of the collagen fibrils at different tissue surfaces. Results For tendon, the anisotropy of amide I and amide II components in parallel sections is comparable to that of regular sections; and tendon's cross sections show distinct, but weak anisotropic behavior for both the amide components. For articular cartilage, parallel sections in the superficial zone have the expected infrared anisotropy that is consistent with that of regular sections. The parallel sections in the radial zone, however, have a nearly isotropic amide II absorption and a distinct amide I anisotropy. Conclusion From the inconsistency in amide anisotropy between superficial to radial zone in parallel section results, a schematic model is used to explain the origins of these amide anisotropies in cartilage and tendon.

  19. Hip joint geometry effects on cartilage contact stresses during a gait cycle. (United States)

    Hui-Hui Wu; Dong Wang; An-Bang Ma; Dong-Yun Gu


    The cartilage surface geometry of natural human hip joint is commonly regarded as sphere. It has been widely applied in computational simulation and hip joint prosthesis design. Some new geometry models have been developed and the sphere assumption has been questioned recently. The objective of this study was to analyze joint geometry effects on cartilage contact stress distribution and investigate contact patterns during a whole gait cycle. Hip surface was reconstructed from CT data of a healthy volunteer. Three finite element (FE) models of hip joint were developed from different cartilage geometries: natural geometry, sphere and rotational ellipsoid. Loads at ten instants of gait cycle were applied to these models based on published in-vivo data. FE predictions of peak contact pressure during gait of natural hip were compared with sphere and rotational ellipsoid replaced hip joint. Contact occurs mainly in upper anterior region of both acetabulum and femur distributing along sagittal plane of human body. It moves towards inferolateral aspect as the resultant joint reaction force changes during walking for natural hip. Peak pressures at the instant with maximum contact force were 7.48 MPa, 14.97 MPa and 13.12 MPa for models with natural hip surface, sphere replaced and rotational ellipsoid replaced surface respectively. During the whole gait cycle, contact pressure of natural hip ranked lowest in most of the instants, followed by rotational ellipsoid replaced and sphere replaced hip. The results indicate that rotational ellipsoid is more consistent with natural hip cartilage geometry than sphere during normal walking. This means rotational ellipsoid prosthesis could give a better description of physiological structure compared with standard sphere prosthesis. Therefore, rotational ellipsoid would be a better choice for prosthesis design.

  20. Regulation of complement by cartilage oligomeric matrix protein allows for a novel molecular diagnostic principle in rheumatoid arthritis

    DEFF Research Database (Denmark)

    Happonen, Kaisa E; Saxne, Tore; Aspberg, Anders


    Cartilage oligomeric matrix protein (COMP) is a structural component of cartilage, where it catalyzes collagen fibrillogenesis. Elevated amounts of COMP are found in serum during increased turnover of cartilage associated with active joint disease, such as rheumatoid arthritis (RA) and osteoarthr...

  1. Synthesis, structure and Hirshfeld surface analysis, vibrational and ...

    Indian Academy of Sciences (India)

    -dimensional architecture. Hirshfeld surface analysis for visually analysing intermolecular interactions in crystal structures employing molecular surfacecontours and 2D fingerprint plots has been used to scrutinize molecular shapes.

  2. Induced collagen cross-links enhance cartilage integration.

    Directory of Open Access Journals (Sweden)

    Aristos A Athens

    Full Text Available Articular cartilage does not integrate due primarily to a scarcity of cross-links and viable cells at the interface. The objective of this study was to test the hypothesis that lysyl-oxidase, a metalloenzyme that forms collagen cross-links, would be effective in improving integration between native-to-native, as well as tissue engineered-to-native cartilage surfaces. To examine these hypotheses, engineered cartilage constructs, synthesized via the self-assembling process, as well as native cartilage, were implanted into native cartilage rings and treated with lysyl-oxidase for varying amounts of time. For both groups, lysyl-oxidase application resulted in greater apparent stiffness across the cartilage interface 2-2.2 times greater than control. The construct-to-native lysyl-oxidase group also exhibited a statistically significant increase in the apparent strength, here defined as the highest observed peak stress during tensile testing. Histology indicated a narrowing gap at the cartilage interface in lysyl-oxidase treated groups, though this alone is not sufficient to indicate annealing. However, when the morphological and mechanical data are taken together, the longer the duration of lysyl-oxidase treatment, the more integrated the interface appeared. Though further data are needed to confirm the mechanism of action, the enhancement of integration may be due to lysyl-oxidase-induced pyridinoline cross-links. This study demonstrates that lysyl-oxidase is a potent agent for enhancing integration between both native-to-native and native-to-engineered cartilages. The fact that interfacial strength increased manifold suggests that cross-linking agents should play a significant role in solving the difficult problem of cartilage integration. Future studies must examine dose, dosing regimen, and cellular responses to lysyl-oxidase to optimize its application.

  3. Tailored PVA/ECM Scaffolds for Cartilage Regeneration

    Directory of Open Access Journals (Sweden)

    Elena Stocco


    Full Text Available Articular cartilage lesions are a particular challenge for regenerative medicine due to cartilage low self-ability repair in case of damage. Hence, a significant goal of musculoskeletal tissue engineering is the development of suitable structures in virtue of their matrix composition and biomechanical properties. The objective of our study was to design in vitro a supporting structure for autologous chondrocyte growth. We realized a biohybrid composite scaffold combining a novel and nonspecific extracellular matrix (ECM, which is decellularized Wharton’s jelly ECM, with the biomechanical properties of the synthetic hydrogel polyvinyl alcohol (PVA. Wharton’s jelly ECM was tested for its ability in promoting scaffold colonization by chondrocytes and compared with polyvinyl alcohol itself and the more specific decellularized cartilage matrix. Our preliminary evidences highlighted the chance of using Wharton’s jelly ECM in combination with PVA hydrogels as an innovative and easily available scaffold for cartilage restoration.

  4. Multimodal nonlinear optical imaging of cartilage development in mouse model (United States)

    He, Sicong; Xue, Wenqian; Sun, Qiqi; Li, Xuesong; Huang, Jiandong; Qu, Jianan Y.


    Kinesin-1 is a kind of motor protein responsible for intracellular transportation and has been studied in a variety of tissues. However, its roles in cartilage development are not clear. In this study, a kinesin-1 heavy chain (Kif5b) knockout mouse model is used to study the functions of kinesin-1 in the cartilage development. We developed a multimodal nonlinear optical (NLO) microscope system integrating stimulated Raman scattering (SRS), second harmonic generation (SHG) and two-photon excited fluorescence (TPEF) to investigate the morphological and biomedical characteristics of fresh tibial cartilage from normal and mutant mice at different developmental stages. The combined forward and backward SHG imaging resolved the fine structure of collagen fibrils in the extracellular matrix of cartilage. Meanwhile, the chondrocyte morphology in different zones of cartilage was visualized by label-free SRS and TPEF images. The results show that the fibrillar collagen in the superficial zone of cartilage in postnatal day 10 and 15 (P10 and P15) knockout mice was significantly less than that of control mice. Moreover, we observed distorted morphology and disorganization of columnar arrangement of chondrocytes in the growth plate cartilage of mutant mice. This study reveals the significant roles of kinesin-1 in collagen formation and chondrocyte morphogenesis.

  5. Fragmentation pathways of nanofractal structures on surfaces

    DEFF Research Database (Denmark)

    Dick, Veronika V.; Solov'yov, Ilia; Solov'yov, Andrey V.


    We present a theoretical analysis of the post-growth processes occurring in nanofractals grown on a surface. For this study we have developed a method that accounts for the internal dynamics of particles in a fractal. We demonstrate that the detachment of particles from the fractal...... and their diffusion within the fractal and over the surface determines the shape of the islands remaining on a surface after the fractal fragmentation. We consider different scenarios of fractal post-growth relaxation and analyze the time evolution of the island's morphology. The results of our calculations...

  6. Infrapatellar fat pad aggravates degeneration of acute traumatized cartilage: a possible role for interleukin-6. (United States)

    He, J; Jiang, Y; Alexander, P G; Ulici, V; Zhu, Y; Wu, S; Tuan, R S


    The infrapatellar fat pad (IPFP), which is located underneath the patella, close to cartilage surfaces, functions in distributing mechanical load and has been shown to produce cytokines. This study aims to assess the involvement of the IPFP in the progression of post-traumatic osteoarthritis (OA) through investigating the crosstalk between the IPFP and injured cartilage in vitro. A single blunt impact (36 MPa) on healthy bovine articular cartilage explants was used to generate traumatized cartilage. Conditioned media from IPFP and traumatized cartilage (FP-CM and TC-CM) were prepared separately. After culturing in FP-CM, the posttraumatic cartilage explants were analyzed for expression of cartilage degeneration associated genes and secretion of the interleukin (IL)-6, into the culture medium. The effect of traumatized cartilage on IPFP was studied by treating IPFP-derived adipocytes and IPFP adipose-derived stromal cells (ADSC) with TC-CM followed by analysis of cytokine expression. FP-CM aggravated glycosaminoglycan (GAG) release in traumatized cartilage, but did not significantly affect healthy cartilage. FP-CM raised gene expression of cyclooxygenase-2, inducible nitric oxide synthase, and IL-6 in traumatized cartilage explants, and lowered expression of tissue inhibitor of metalloproteinases-1, 2, 3, compared to non-conditioned medium. Of particular significance is that medium IL-6 levels increased substantially in both FP-CM and FP-CM treated traumatized cartilage cultures. Extrinsic IL-6 treatment of traumatized cartilage simulated part of the effects of FP-CM. TC-CM elevated levels of IL-6 expression in IPFP derived adipocytes and ADSCs. IPFP aggravates post-traumatized cartilage degeneration, and IL-6 is a candidate tissue degeneration mediator. Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  7. Mechanical Testing of Cartilage Constructs. (United States)

    Olvera, Dinorath; Daly, Andrew; Kelly, Daniel John


    A key goal of functional cartilage tissue engineering is to develop constructs with mechanical properties approaching those of the native tissue. Herein we describe a number of tests to characterize the mechanical properties of tissue engineered cartilage. Specifically, methods to determine the equilibrium confined compressive (or aggregate) modulus, the equilibrium unconfined compressive (or Young's) modulus, and the dynamic modulus of tissue engineered cartilaginous constructs are described. As these measurements are commonly used in both the articular cartilage mechanics literature and the cartilage tissue engineering literature to describe the mechanical functionality of cartilaginous constructs, they facilitate comparisons to be made between the properties of native and engineered tissues.

  8. Hydroxyl migration disorders the surface structure of hydroxyapatite nanoparticles (United States)

    Cheng, Xiajie; Wu, Hong; Zhang, Li; Ma, Xingtao; Zhang, Xingdong; Yang, Mingli


    The surface structure of nano-hydroxyapatite (HAP) was investigated using a combined simulated annealing and molecular dynamics method. The stationary structures of nano-HAP with 4-7 nm in diameter and annealed under different temperatures were analyzed in terms of pair distribution function, structural factor, mean square displacement and atomic coordination number. The particles possess different structures from bulk crystal. A clear radial change in their atomic arrangements was noted. From core to surface the structures change from ordered to disordered. A three-shell model was proposed to describe the structure evolution of nano-HAP. Atoms in the core zone keep their arrangements as in crystal, while atoms in the surface shell are in short-range order and long-range disorder, adopting a typically amorphous structure. Atoms in the middle shell have small displacements and/or deflections but basically retain their original locations as in crystal. The disordered shell is about 1 nm in thickness, in agreement with experimental observations. The disordering mainly stems from hydroxyl migration during which hydroxyls move to the surface and bond with the exposed Ca ions, and their left vacancies bring about a rearrangement of nearby atoms. The disordering is to some extent different for particles unannealed under different temperatures, resulting from fewer number of migrated hydroxyls at lower temperatures. Particles with different sizes have similar surface structures, and their surface energy decreases with increasing size. Moreover, the surface energy is reduced by hydroxyl migration because the exposed Ca ions on the surface are ionically bonded with the migrated hydroxyls. Our calculations proposed a new structure model for nano-HAP, which indicates a surface structure with activities different from those without surface reorganization. This is particularly interesting because most bioactivities of biomaterials are dominated by their surface activity.

  9. Smooth structure of some symplectic surfaces


    Vidussi, Stefano


    In this note we present a new definition of the 4-manifold admitting inequivalent symplectic structures constructed by McMullen-Taubes which leads to the identification of a new symplectic structure. We prove moreover that it is diffeomorphic to one of the link surgery manifolds introduced by Fintushel-Stern.

  10. Structural Changes in the Surface Friction Layer of a Polymeric Endoprosthesis Cup (United States)

    Tsvetkova, E. A.; Kadolich, Zh. V.; Goldade, V. A.; Pinchuk, L. S.


    A concept of creation of a polymeric insert for hip joint endoprostheses with the physiological and biomechanical properties typical of natural cartilage is proposed. The spherical friction surface of the insert is coated with a microporous layer imitating cartilage. This layer carries an electret charge, which improves the lubrication of the endoprosthesis with synovia and serves as a carrier of drugs, thus ensuring their prolonged discharge into the operation wound. Tribotechnical characteristics of an endoprosthesis with such an insert are investigated. It is shown that a drop in the friction coefficient of such a pair is accompanied by a change in the microrelief of the friction surface and in the degree of crystallinity of the material of the porous layer.

  11. Detection of a periodic structure embedded in surface roughness, for ...

    Indian Academy of Sciences (India)

    Abstract. This paper deals with surface profilometry, where we try to detect a periodic structure, hidden in randomness using the matched filter method of analysing the intensity of light, scattered from the surface. From the direct problem of light scattering from a composite rough surface of the above type, we find that the ...

  12. Metrology of sub-micron structured polymer surfaces

    DEFF Research Database (Denmark)

    Quagliotti, Danilo; Tosello, Guido; Salaga, J.

    surface replication of the tool insert component when moulding the polymer melt [1]. This aspect is particularly critical when dealing with increasingly small dimensional scales in micro- and nano-structured surfaces [2, 3].In this context, a metrological investigation of polymer replicated surfaces using...

  13. Structural optimization of super-repellent surfaces

    DEFF Research Database (Denmark)

    Cavalli, Andrea; Bøggild, Peter; Okkels, Fridolin


    Micro-patterning is an effective way to achieve surfaces with extreme liquid repellency. This technique does not rely on chemical coatings and is therefore a promising concept for application in food processing and bio-compatibile coatings. This super-repellent behaviour is obtained by suspending...

  14. Polymer Mechanics as a Model for Short-Term and Flow-Independent Cartilage Viscoelasticity (United States)

    June, R. K.; Neu, C. P.; Barone, J. R.; Fyhrie, D. P.


    Articular cartilage is the load bearing soft tissue that covers the contacting surfaces of long bones in articulating joints. Healthy cartilage allows for smooth joint motion, while damaged cartilage prohibits normal function in debilitating joint diseases such as osteoarthritis. Knowledge of cartilage mechanical function through the progression of osteoarthritis, and in response to innovative regeneration treatments, requires a comprehensive understanding of the molecular nature of interacting extracellular matrix constituents and interstitial fluid. The objectives of this study were therefore to (1) examine the timescale of cartilage stress-relaxation using different mechanistic models and (2) develop and apply a novel (termed “sticky”) polymer mechanics model to cartilage stress-relaxation based on temporary binding of constituent macromolecules. Using data from calf cartilage samples, we found that different models captured distinct timescales of cartilage stress-relaxation: monodisperse polymer reptation best described the first second of relaxation, sticky polymer mechanics best described data from ∼1-100 seconds of relaxation, and a model of inviscid fluid flow through a porous elastic matrix best described data from 100 seconds to equilibrium. Further support for the sticky polymer model was observed using experimental data where cartilage stress-relaxation was measured in either low or high salt concentration. These data suggest that a complete understanding of cartilage mechanics, especially in the short time scales immediately following loading, requires appreciation of both fluid flow and the polymeric behavior of the extracellular matrix. PMID:21552375

  15. Repair of articular cartilage defects by tissue-engineered cartilage constructed with adipose-derived stem cells and acellular cartilaginous matrix in rabbits. (United States)

    Wang, Z J; An, R Z; Zhao, J Y; Zhang, Q; Yang, J; Wang, J B; Wen, G Y; Yuan, X H; Qi, X W; Li, S J; Ye, X C


    After injury, inflammation, or degeneration, articular cartilage has limited self-repair ability. We aimed to explore the feasibility of repair of articular cartilage defects with tissue-engineered cartilage constructed by acellular cartilage matrices (ACMs) seeded with adipose-derived stem cells (ADSCs). The ADSCs were isolated from 3-month-old New Zealand albino rabbit by using collagenase and cultured and amplified in vitro. Fresh cartilage isolated from adult New Zealand albino rabbit were freeze-dried for 12 h and treated with Triton X-100, DNase, and RNase to obtain ACMs. ADSCs were seeded in the acellular cartilaginous matrix at 2x10(7)/mL, and cultured in chondrogenic differentiation medium for 2 weeks to construct tissue-engineered cartilage. Twenty-four New Zealand white rabbits were randomly divided into A, B, and C groups. Engineered cartilage was transplanted into cartilage defect position of rabbits in group A, group B obtained ACMs, and group C did not receive any transplants. The rabbits were sacrificed in week 12. The restored tissue was evaluated using macroscopy, histology, immunohistochemistry, and transmission electron microscopy (TEM). In the tissue-engineered cartilage group (group A), articular cartilage defects of the rabbits were filled with chondrocyte-like tissue with smooth surface. Immunohistochemistry showed type II-collagen expression and Alcian blue staining was positive. TEM showed chondrocytes in the recesses, with plenty of secretary matrix particles. In the scaffold group (group B), the defect was filled with fibrous tissue. No repaired tissue was found in the blank group (group C). Tissue-engineered cartilage using ACM seeded with ADSCs can help repair articular cartilage defects in rabbits.

  16. One-Step Cartilage Repair Technique as a Next Generation of Cell Therapy for Cartilage Defects: Biological Characteristics, Preclinical Application, Surgical Techniques, and Clinical Developments. (United States)

    Zhang, Chi; Cai, You-Zhi; Lin, Xiang-Jin


    To provide a comprehensive overview of the basic science rationale, surgical technique, and clinical outcomes of 1-step cartilage repair technique used as a treatment strategy for cartilage defects. A systematic review was performed in the main medical databases to evaluate the several studies concerning 1-step procedures for cartilage repair. The characteristics of cell-seed scaffolds, behavior of cells seeded into scaffolds, and surgical techniques were also discussed. Clinical outcomes and quality of repaired tissue were assessed using several standardized outcome assessment tools, magnetic resonance imaging scans, and biopsy histology. One-step cartilage repair could be divided into 2 types: chondrocyte-matrix complex (CMC) and autologous matrix-induced chondrogenesis (AMIC), both of which allow a simplified surgical approach. Studies with Level IV evidence have shown that 1-step cartilage repair techniques could significantly relieve symptoms and improve functional assessment (P step cartilage repair technique, with its potential for effective, homogeneous distribution of chondrocytes and multipotent stem cells on the surface of the cartilage defect, is able to regenerate hyaline-like cartilage tissue, and it could be applied to cartilage repair by arthroscopy. Level IV, systematic review of Level II and IV studies. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  17. Biochemical composition of the superficial layer of articular cartilage. (United States)

    Crockett, R; Grubelnik, A; Roos, S; Dora, C; Born, W; Troxler, H


    To gain more information on the mechanism of lubrication in articular joints, the superficial layer of bovine articular cartilage was mechanically removed in a sheet of ice that formed on freezing the cartilage. Freeze-dried samples contained low concentrations of chondroitin sulphate and protein. Analysis of the protein by SDS PAGE showed that the composition of the sample was comparable to that of synovial fluid (SF). Attenuated total reflection infrared (ATR-IR) spectroscopy of the dried residue indicated that the sample contained mostly hyaluronan. Moreover, ATR-IR spectroscopy of the upper layer of the superficial layer, adsorbed onto silicon, showed the presence of phospholipids. A gel could be formed by mixing hyaluronan and phosphatidylcholine in water with mechanical properties similar to those of the superficial layer on cartilage. Much like the superficial layer of natural cartilage, the surface of this gel became hydrophobic on drying out. Thus, it is proposed that the superficial layer forms from hyaluronan and phospholipids, which associate by hydrophobic interactions between the alkyl chains of the phospholipids and the hydrophobic faces of the disaccharide units in hyaluronan. This layer is permeable to material from the SF and the cartilage, as shown by the presence of SF proteins and chondroitin sulphate. As the cartilage dries out after removal from the joint, the phospholipids migrate towards the surface of the superficial layer to reduce the surface tension. It is also proposed that the highly efficient lubrication in articular joints can, at least in part, be attributed to the ability of the superficial layer to adsorb and hold water on the cartilage surface, thus creating a highly viscous boundary protection. Copyright 2007 Wiley Periodicals, Inc.

  18. Surface Nano-Structuring by Adsorption and Chemical Reactions

    Directory of Open Access Journals (Sweden)

    Ken-ichi Tanaka


    Full Text Available Nano-structuring of the surface caused by adsorption of molecules or atoms and by the reaction of surface atoms with adsorbed species are reviewed from a chemistry viewpoint. Self-assembly of adsorbed species is markedly influenced by weak mutual interactions and the local strain of the surface induced by the adsorption. Nano-structuring taking place on the surface is well explained by the notion of a quasi-molecule provided by the reaction of surface atoms with adsorbed species. Self-assembly of quasi-molecules by weak internal bonding provides quasi-compounds on a specific surface. Various nano-structuring phenomena are discussed: (i self-assembly of adsorbed molecules and atoms; (ii self-assembly of quasi-compounds; (iii formation of nano-composite surfaces; (iv controlled growth of nano-materials on composite surfaces. Nano-structuring processes are not always controlled by energetic feasibility, that is, the formation of nano-composite surface and the growth of nano-particles on surfaces are often controlled by the kinetics. The idea of the “kinetic controlled molding” might be valuable to design nano-materials on surfaces.

  19. The architecture of cartilage: Elemental maps and scanning transmission ion microscopy/tomography

    Energy Technology Data Exchange (ETDEWEB)

    Reinert, Tilo E-mail:; Reibetanz, Uta; Schwertner, Michael; Vogt, Juergen; Butz, Tilman; Sakellariou, Arthur


    Articular cartilage is not just a jelly-like cover of the bone within the joints but a highly sophisticated architecture of hydrated macromolecules, collagen fibrils and cartilage cells. Influences on the physiological balance due to age-related or pathological changes can lead to malfunction and subsequently to degradation of the cartilage. Many activities in cartilage research are dealing with the architecture of joint cartilage but have limited access to elemental distributions. Nuclear microscopy is able to yield spatially resolved elemental concentrations, provides density information and can visualise the arrangement of the collagen fibres. The distribution of the cartilage matrix can be deduced from the elemental and density maps. The findings showed a varying content of collagen and proteoglycan between zones of different cell maturation. Zones of higher collagen content are characterised by aligned collagen fibres that can form tubular structures. Recently we focused on STIM tomography to investigate the three dimensional arrangement of the collagen structures.

  20. Structural and electronic properties of hydrosilylated silicon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Baumer, A.


    The structural and electronic properties of alkyl-terminated Si surfaces prepared by thermallyinduced hydrosilylation have been studied in detail in the preceding chapters. Various surfaces have been used for the functionalization ranging from crystalline Si over amorphous hydrogenated Si to nanoscaled materials such as Si nanowires and nanoparticles. In each case, the alkyl-terminated surfaces have been compared to the native oxidized and H-terminated surfaces. (orig.)

  1. Starch-modified magnetite nanoparticles for impregnation into cartilage (United States)

    Soshnikova, Yulia M.; Roman, Svetlana G.; Chebotareva, Natalia A.; Baum, Olga I.; Obrezkova, Mariya V.; Gillis, Richard B.; Harding, Stephen E.; Sobol, Emil N.; Lunin, Valeriy V.


    The paper presents preparation and characterization of starch-modified Fe3O4 nanoparticles (NPs) in aqueous dispersion after impregnation into healthy and damaged types of cartilage. We show that starch-modified dispersion has a narrower size distribution than a non-stabilized one. The average hydrodynamic radius of magnetite NPs in a dispersion used for impregnation into cartilage is (48 ± 1) nm with the width of the distribution from 5 to 200 nm. We investigate stability of aqueous magnetite NPs dispersions during storage and with increase in temperature (up to 70 °C). We find that polydisperse magnetite NPs can penetrate into cartilage and the size and concentration of impregnated particles depend on the organization of the tissue structure. The results confirm the possibility of application of magnetite NPs in diagnostics and laser treatment of degenerative cartilage deceases.

  2. Structured surfaces for a giant liquid slip. (United States)

    Lee, Choongyeop; Choi, Chang-Hwan; Kim, Chang-Jin Cj


    We study experimentally how two key geometric parameters (pitch and gas fraction) of textured hydrophobic surfaces affect liquid slip. The two are independently controlled on precisely fabricated microstructures of posts and grates, and the slip length of water on each sample is measured using a rheometer system. The slip length increases linearly with the pitch but dramatically with the gas fraction above 90%, the latter trend being more pronounced on posts than on grates. Once the surfaces are designed for very large slips (>20 microm), however, further increase is not obtained in regular practice because the meniscus loses its stability. By developing near-perfect samples that delay the transition from a dewetted (Cassie) to a wetted (Wenzel) state until near the theoretical limit, we achieve giant slip lengths, as large as 185 microm.

  3. On the structure of Si(100) surface

    DEFF Research Database (Denmark)

    Back, Seoin; Schmidt, Johan Albrecht; Ji, Hyunjun


    )]. Interestingly, however, the MRCI + Q, MRAQCC, and MRACPF results (which give a more refined description of electron correlation effects) suggest that the buckled dimer is marginally more stable than its symmetric counterpart. The present study underlines the significance of having an accurate description...... density functional based calculations predict the dimers to be buckled, while most wavefunction based correlated treatments prefer the symmetric configurations. Here, we use the doubly hybrid density functional (DHDF) geometry optimizations, in particular, XYGJ-OS, complete active space self...... of the electron-electron correlation as well as proper multireference wave functions when exploring the extremely delicate potential energy surfaces of the reconstructed Si(100) surface. (C) 2013 AIP Publishing LLC....

  4. Biomimetic surface structuring using cylindrical vector femtosecond laser beams


    Evangelos Skoulas; Alexandra Manousaki; Costas Fotakis; Emmanuel Stratakis


    We report on a new, single-step and scalable method to fabricate highly ordered, multi-directional and complex surface structures that mimic the unique morphological features of certain species found in nature. Biomimetic surface structuring was realized by exploiting the unique and versatile angular profile and the electric field symmetry of cylindrical vector (CV) femtosecond (fs) laser beams. It is shown that, highly controllable, periodic structures exhibiting sizes at nano-, micro- and d...

  5. Surface Structure Enhanced Microchannel Flow Boiling


    Zhu, Yangying; Antao, Dion Savio; Chu, Kuang-Han; Chen, Siyu; Hendricks, Terry J.; Zhang, Tiejun; Wang, Evelyn N.


    We investigated the role of surface microstructures in two-phase microchannels on suppressing flow instabilities and enhancing heat transfer. We designed and fabricated microchannels with well-defined silicon micropillar arrays on the bottom heated microchannel wall to promote capillary flow for thin film evaporation while facilitating nucleation only from the sidewalls. Our experimental results show significantly reduced temperature and pressure drop fluctuation especially at high heat fluxe...

  6. Structure of Solids Surfaces in Wear Situations. (United States)


    lactones , respectively. As pointed out by Greenler 12J, the most intense emission bands from a material adsorbed in a thin layer on a metal surface...peroxides are formed instead of hydroper-.,. .," ", oxides. The decomposition of these peroxides then leads to unsaturates , aldehydes, ketones and...around 1100 cm-1 (OH and unsaturation ) and at 730 cm-1 (CH2 rock). weeIt is clear that such analyses are difficult, but can yield a welthof information

  7. Cartilage Injuries in the Adult Knee (United States)

    Moyad, Thomas F.


    Cartilage injuries are frequently recognized as a source of significant morbidity and pain in patients with previous knee injuries. The majority of patients who undergo routine knee arthroscopy have evidence of a chondral defect. These injuries represent a continuum of pathology from small, asymptomatic lesions to large, disabling defects affecting a major portion of one or more compartments within the knee joint. In comparison to patients with osteoarthritis, individuals with isolated chondral surface damage are often younger, significantly more active, and usually less willing to accept limitations in activities that require higher impact. At the present time, a variety of surgical procedures exist, each with their unique indications. This heterogeneity of treatment options frequently leads to uncertainty regarding which techniques, if any, are most appropriate for patients. The purpose of this review is to describe the workup and discuss the management techniques for cartilage injuries within the adult knee. PMID:26069581

  8. First shark from the Late Devonian (Frasnian Gogo Formation, Western Australia sheds new light on the development of tessellated calcified cartilage.

    Directory of Open Access Journals (Sweden)

    John A Long

    Full Text Available Living gnathostomes (jawed vertebrates comprise two divisions, Chondrichthyes (cartilaginous fishes, including euchondrichthyans with prismatic calcified cartilage, and extinct stem chondrichthyans and Osteichthyes (bony fishes including tetrapods. Most of the early chondrichthyan ('shark' record is based upon isolated teeth, spines, and scales, with the oldest articulated sharks that exhibit major diagnostic characters of the group--prismatic calcified cartilage and pelvic claspers in males--being from the latest Devonian, c. 360 Mya. This paucity of information about early chondrichthyan anatomy is mainly due to their lack of endoskeletal bone and consequent low preservation potential.Here we present new data from the first well-preserved chondrichthyan fossil from the early Late Devonian (ca. 380-384 Mya Gogo Formation Lägerstatte of Western Australia. The specimen is the first Devonian shark body fossil to be acid-prepared, revealing the endoskeletal elements as three-dimensional undistorted units: Meckel's cartilages, nasal, ceratohyal, basibranchial and possible epibranchial cartilages, plus left and right scapulocoracoids, as well as teeth and scales. This unique specimen is assigned to Gogoselachus lynnbeazleyae n. gen. n. sp.The Meckel's cartilages show a jaw articulation surface dominated by an expansive cotylus, and a small mandibular knob, an unusual condition for chondrichthyans. The scapulocoracoid of the new specimen shows evidence of two pectoral fin basal articulation facets, differing from the standard condition for early gnathostomes which have either one or three articulations. The tooth structure is intermediate between the 'primitive' ctenacanthiform and symmoriiform condition, and more derived forms with a euselachian-type base. Of special interest is the highly distinctive type of calcified cartilage forming the endoskeleton, comprising multiple layers of nonprismatic subpolygonal tesserae separated by a cellular matrix

  9. Characterisation of mineralisation of bone and cartilage: X-ray diffraction and Ca and Sr K{sub {alpha}} X-ray fluorescence microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, D.A. [Centre for Nuclear and Radiation Physics, Department of Physics, University of Surrey, Guildford, Surrey, GU2 7XH (United Kingdom)], E-mail:; Muthuvelu, P.; Ellis, R.E.; Green, E.M.; Attenburrow, D. [Biomedical Physics Group, School of Physics, University of Exeter, Exeter (United Kingdom); Barrett, R. [ESRF, BP 220, F-38043 Grenoble Cedex (France); Arkill, K.; Colridge, D.B.; Winlove, C.P. [Biomedical Physics Group, School of Physics, University of Exeter, Exeter (United Kingdom)


    Bone is a dynamic structure, constantly remodelling in response to changing mechanical and environmental factors. This is particularly evident in the mineral component encrusting the collagenous framework. The mineral is principally in the form of calcium apatite, but calcium can exchange with strontium, both during the cellular processes of mineralisation and resorption and by passive exchange with the deposited crystals. Mineralisation is generally characterized by densitometry, but because of the differences in absorption cross sections of calcium and strontium it can be misleading in studies of composition. In this work we have used X-ray diffraction to identify calcium and strontium apatite and X-ray fluorescence to quantify strontium and calcium distribution. With the beam characteristics available from synchrotron radiation, this has enabled us to obtain microscopic resolution on thin sections of bone and cartilage from the equine metacarpophalangeal joint. Two issues have been investigated; the first is the distribution of mineral in the bone-cartilage interface and within individual trabeculae. In trabecular bone the ratio of strontium to calcium concentration was typically 0.0035 {+-} 0.0020, and higher by a factor of {approx}3 at the periphery than in the centre of a trabeculum (possibly reflecting the more rapid turnover of mineral in the surface layer). In the dense subchondral bone the ratio was similar, approximately doubling in the calcified cartilage. The second objective was to explore the changes in mineralisation associated with development of osteoarthrosis. We analysed lesions showing cartilage thinning and changes in the trabecular organization and density of the underlying bone. At the centre of the lesion the ratio of strontium to calcium was much lower than that in normal tissue, although the calcified cartilage still showed a higher ratio than the underlying bone. In the superficially normal tissue around the lesion the calcified

  10. First shark from the Late Devonian (Frasnian) Gogo Formation, Western Australia sheds new light on the development of tessellated calcified cartilage. (United States)

    Long, John A; Burrow, Carole J; Ginter, Michal; Maisey, John G; Trinajstic, Kate M; Coates, Michael I; Young, Gavin C; Senden, Tim J


    Living gnathostomes (jawed vertebrates) comprise two divisions, Chondrichthyes (cartilaginous fishes, including euchondrichthyans with prismatic calcified cartilage, and extinct stem chondrichthyans) and Osteichthyes (bony fishes including tetrapods). Most of the early chondrichthyan ('shark') record is based upon isolated teeth, spines, and scales, with the oldest articulated sharks that exhibit major diagnostic characters of the group--prismatic calcified cartilage and pelvic claspers in males--being from the latest Devonian, c. 360 Mya. This paucity of information about early chondrichthyan anatomy is mainly due to their lack of endoskeletal bone and consequent low preservation potential. Here we present new data from the first well-preserved chondrichthyan fossil from the early Late Devonian (ca. 380-384 Mya) Gogo Formation Lägerstatte of Western Australia. The specimen is the first Devonian shark body fossil to be acid-prepared, revealing the endoskeletal elements as three-dimensional undistorted units: Meckel's cartilages, nasal, ceratohyal, basibranchial and possible epibranchial cartilages, plus left and right scapulocoracoids, as well as teeth and scales. This unique specimen is assigned to Gogoselachus lynnbeazleyae n. gen. n. sp. The Meckel's cartilages show a jaw articulation surface dominated by an expansive cotylus, and a small mandibular knob, an unusual condition for chondrichthyans. The scapulocoracoid of the new specimen shows evidence of two pectoral fin basal articulation facets, differing from the standard condition for early gnathostomes which have either one or three articulations. The tooth structure is intermediate between the 'primitive' ctenacanthiform and symmoriiform condition, and more derived forms with a euselachian-type base. Of special interest is the highly distinctive type of calcified cartilage forming the endoskeleton, comprising multiple layers of nonprismatic subpolygonal tesserae separated by a cellular matrix, interpreted

  11. Growth factors and cartilage repair.

    NARCIS (Netherlands)

    Berg, W.B. van den; Kraan, P.M. van der; Scharstuhl, A.; Beuningen, H.M. van


    Growth factors are obvious tools to enhance cartilage repair. Understanding of reactivities in normal and arthritic cartilage and potential side effects on other compartments in the joint will help to identify possibilities and limitations. Growth factor responses have been evaluated in normal and

  12. Regulators of articular cartilage homeostasis

    NARCIS (Netherlands)

    Leijten, Jeroen Christianus Hermanus


    Prevention of hypertrophic differentiation is essential for successful cartilage repair strategies. Although this process is essential for longitudinal growth, it also is part of degenerative cartilage diseases such as osteoarthiritis. Moreover, it limits the use of cell types prone to this process

  13. Surface Structure of Hydroxyapatite from Simulated Annealing Molecular Dynamics Simulations. (United States)

    Wu, Hong; Xu, Dingguo; Yang, Mingli; Zhang, Xingdong


    The surface structure of hydroxyapatite (HAP) is crucial for its bioactivity. Using a molecular dynamics simulated annealing method, we studied the structure and its variation with annealing temperature of the HAP (100) surface. In contrast to the commonly used HAP surface model, which is sliced from HAP crystal and then relaxed at 0 K with first-principles or force-field calculations, a new surface structure with gradual changes from ordered inside to disordered on the surface was revealed. The disordering is dependent on the annealing temperature, Tmax. When Tmax increases up to the melting point, which was usually adopted in experiments, the disordering increases, as reflected by its radial distribution functions, structural factors, and atomic coordination numbers. The disordering of annealed structures does not show significant changes when Tmax is above the melting point. The thickness of disordered layers is about 10 Å. The surface energy of the annealed structures at high temperature is significantly less than that of the crystal structure relaxed at room temperature. A three-layer model of interior, middle, and surface was then proposed to describe the surface structure of HAP. The interior layer retains the atomic configurations in crystal. The middle layer has its atoms moved and its groups rotated about their original locations. In the surface layer, the atomic arrangements are totally different from those in crystal. In particular for the hydroxyl groups, they move outward and cover the Ca(2+) ions, leaving holes occupied by the phosphate groups. Our study suggested a new model with disordered surface structures for studying the interaction of HAP-based biomaterials with other molecules.

  14. Articular cartilage bioreactors and bioprocesses. (United States)

    Darling, Eric M; Athanasiou, Kyriacos A


    This review summarizes the major approaches for developing articular cartilage, using bioreactors and mechanical stimuli. Cartilage cells live in an environment heavily influenced by mechanical forces. The development of cartilaginous tissue is dependent on the environment that surrounds it, both in vivo and in vitro. Chondrocytes must be cultured in a way that gives them the proper concentration of nutrients and oxygen while removing wastes. A mechanical force must also be applied during the culturing process to produce a phenotypically correct tissue. Four main types of forces are currently used in cartilage-culturing processes: hydrostatic pressure, direct compression, "high"-shear fluid environments, and "low"-shear fluid environments. All these forces have been integrated into culturing devices that serve as bioreactors for articular cartilage. The strengths and weaknesses of each device and stimulus are explored, as is the future of cartilage bioreactors.

  15. Synthesis, structural and surface morphological characterizations of ...

    African Journals Online (AJOL)

    Sulfated zirconia (SZ) nanoparticles (NPs) were successfully synthesized and deposited via chemical route called sol-gel technique. The structural, morphological, and optical properties the samples were investigated by X-ray diffraction (XRD), Energy Dispersive X-ray Spectrometry (EDX), Scanning Electron Microscopy ...

  16. Iridescent flowers? : Contribution of surface structures to optical signaling

    NARCIS (Netherlands)

    van der Kooi, Casper J.; Wilts, Bodo D.; Leertouwer, Hein L.; Staal, Marten; Elzenga, J. Theo M.; Stavenga, Doekele G.

    The color of natural objects depends on how they are structured and pigmented. In flowers, both the surface structure of the petals and the pigments they contain determine coloration. The aim of the present study was to assess the contribution of structural coloration, including iridescence, to

  17. Self-collimation phenomena of surface waves in structured perfect electric conductors and metal surfaces. (United States)

    Oh, Sang Soon; Lee, Sun-Goo; Kim, Jae-Eun; Park, Hae Yong


    We demonstrate that surface waves in structured perfect electric conductor surfaces can be self-collimated using the finite-difference time-domain method. The self-collimation frequency is obtained from the equi-frequency contours of a perfect electric conductor patterned with an array of square holes. The field patterns of the self-collimated surface wave, obtained using the periodic boundary conditions, show that the surface waves propagate with almost no spreading. We also show that self-collimation phenomena can be observed for the hybrid surface plasmon waves in structured metal surfaces using the finite-difference time-domain method with the Drude model. It is shown that for a structured silver surface the self-collimation can be achieved at the frequencies in the infrared region.

  18. Transplantation of rib cartilage reshaped with 1.56 μm laser radiation in rabbits (United States)

    Sobol, E.; Baum, O.; Alexandrovskaya, Yu.; Shekhter, A.; Selezneva, L.; Svistuskin, V.


    As cartilage is an ideal natural material for transplantation, its use in the ENT surgery is limited by a difficulty to get proper shape of cartilage implants. Aim of the work is to make ring-shaped cartilage implants, to check their stability after laser reshaping and to perform transplantation into rabbits in vivo. We experimented with costal cartilages of 1-2 mm in thickness obtained from 3rd and 4rd ribs of a rabbit. 1.56 μm laser (Arcuo Medical Inc.) was used for cartilage reshaping. The laser settings were established taking into account anisotropy of cartilage structure for different orientation of the implants. The reshaped cartilage implants were surgically sewn to rib cartilages of the other rabbits. The rabbits were slaughtered in 3.5-4 months after surgery. The results have shown that (1) all reshaped implants kept circular form, and (2) the implants were adhered to the native rabbit cartilage sites (3) pronounced signs of regeneration in the intermediate zones were observed. The prospects of the cartilage implants use in larynx stenosis surgery are discussed.

  19. Surfaces of Microparticles in Colloids: Structure and Molecular Adsorption Kinetics (United States)

    Dai, Hai-Lung


    Surfaces of micron and sub-micron size particles in liquid solution are probed by second harmonic generation (SHG) facilitated with femtosecond laser pulses. The particles probed include inorganic objects such as carbon black and color pigments, polymeric species like polystyrene beads, and biological systems such as blood cells and ecoli. In the experiments, dye molecules are first adsorbed onto the particle surface to allow generation of second harmonics upon light irradiation. Competition for adsorption between these surface dye molecules and the molecules of interest in the solution is then monitored by the SHG signal to reveal the molecular adsorption kinetics and surface structure. Specifically, surfactant adsorption on polymer surfaces, the structure of carbon black surface, and protein adsorption on biological surfaces, monitored by this technique, will be discussed.

  20. The Influence of Articular Cartilage Thickness Reduction on Meniscus Biomechanics.

    Directory of Open Access Journals (Sweden)

    Piotr Łuczkiewicz

    Full Text Available Evaluation of the biomechanical interaction between meniscus and cartilage in medial compartment knee osteoarthritis.The finite element method was used to simulate knee joint contact mechanics. Three knee models were created on the basis of knee geometry from the Open Knee project. We reduced the thickness of medial cartilages in the intact knee model by approximately 50% to obtain a medial knee osteoarthritis (OA model. Two variants of medial knee OA model with congruent and incongruent contact surfaces were analysed to investigate the influence of congruency. A nonlinear static analysis for one compressive load case was performed. The focus of the study was the influence of cartilage degeneration on meniscal extrusion and the values of the contact forces and contact areas.In the model with incongruent contact surfaces, we observed maximal compressive stress on the tibial plateau. In this model, the value of medial meniscus external shift was 95.3% greater, while the contact area between the tibial cartilage and medial meniscus was 50% lower than in the congruent contact surfaces model. After the non-uniform reduction of cartilage thickness, the medial meniscus carried only 48.4% of load in the medial compartment in comparison to 71.2% in the healthy knee model.We have shown that the change in articular cartilage geometry may significantly reduce the role of meniscus in load transmission and the contact area between the meniscus and cartilage. Additionally, medial knee OA may increase the risk of meniscal extrusion in the medial compartment of the knee joint.

  1. Techniques and Applications of in vivo Diffusion Imaging of Articular Cartilage (United States)

    Raya, José G.


    Early in the process of osteoarthritis (OA) the composition (water, proteoglycan [PG], and collagen) and structure of articular cartilage is altered leading to changes in its mechanical properties. A technique that can assess the composition and structure of the cartilage in vivo can provide insight in the mechanical integrity of articular cartilage and become a powerful tool for the early diagnosis of OA. Diffusion tensor imaging (DTI) has been proposed as a biomarker for cartilage composition and structure. DTI is sensitive to the PG content through the mean diffusivity (MD) and to the collagen architecture through the fractional anisotropy (FA). However, the acquisition of DTI of articular cartilage in vivo is challenging due to the short T2 of articular cartilage (~40 ms at 3 T) and the high resolution needed (0.5–0.7 mm in plane) to depict the cartilage anatomy. We describe the pulse sequences used for in vivo DTI of articular cartilage and discus general strategies for protocol optimization. We provide a comprehensive review of measurements of DTI of articular cartilage from ex vivo validation experiments to its recent clinical applications. PMID:25865215

  2. Influence of surface structure and chemistry on water droplet splashing. (United States)

    Koch, Kerstin; Grichnik, Roland


    Water droplet splashing and aerosolization play a role in human hygiene and health systems as well as in crop culturing. Prevention or reduction of splashing can prevent transmission of diseases between animals and plants and keep technical systems such as pipe or bottling systems free of contamination. This study demonstrates to what extent the surface chemistry and structures influence the water droplet splashing behaviour. Smooth surfaces and structured replicas of Calathea zebrina (Sims) Lindl. leaves were produced. Modification of their wettability was done by coating with hydrophobizing and hydrophilizing agents. Their wetting was characterized by contact angle measurement and splashing behaviour was observed with a high-speed video camera. Hydrophobic and superhydrophilic surfaces generally showed fewer tendencies to splash than hydrophobic ones. Structuring amplified the underlying behaviour of the surface chemistries, increasing hydrophobic surfaces' tendency to splash and decreasing splash on hydrophilic surfaces by quickly transporting water off the impact point by capillary forces. The non-porous surface structures found in C. zebrina could easily be applied to technical products such as plastic foils or mats and coated with hydrophilizing agents to suppress splash in areas of increased hygiene requirements or wherever pooling of liquids is not desirable.This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'. © 2016 The Author(s).

  3. The Dynamics and Structures of Adsorbed Surfaces

    DEFF Research Database (Denmark)

    Nielsen, M; Ellenson, W. D.; McTague, J. P.


    . Elastic neutron diffraction measurements, determining the two-dimensional structural ordering of the adsorbed films, have been performed on layers of N2, Ar, H2, D2, O2, Kr, and He. Measurements on layers of larger molecules such as CD4 and ND3 have also been reported. Inelastic neutron scattering...... of molecules such as NH3 or the internal modes of adsorbed molecules such as C4H10. Neutron scattering measurements where substrates other than graphite products are used as the adsorbents will not be reviewed here. However, the power of the technique will be demonstrated in an example of H2 physisorbed...

  4. Structure sensitivity of CO dissociation on Rh surfaces

    DEFF Research Database (Denmark)

    Mavrikakis, Manos; Baumer, M.; Freund, H.J.


    Using periodic self-consistent density functional calculations it is shown that the barrier for CO dissociation is similar to120 kJ/mol lower on the stepped Rh(211) surface than on the close-packed Rh(111) surface. The stepped surface binds molecular CO and the dissociation products more strongly...... than the flat surface, but the effect is considerably weaker than the effect of surface structure on the dissociation barrier. Our findings are compared with available experimental data, and the consequences for CO activation in methanation and Fischer-Tropsch reactions are discussed....

  5. Correlation between polarization sensitive optical coherence tomography and SHG microscopy in articular cartilage (United States)

    Zhou, Xin; Ju, Myeong Jin; Huang, Lin; Tang, Shuo


    Polarization-sensitive optical coherence tomography (PS-OCT) and second harmonic generation (SHG) microscopy are two imaging modalities with different resolutions, field-of-views (FOV), and contrasts, while they both have the capability of imaging collagen fibers in biological tissues. PS-OCT can measure the tissue birefringence which is induced by highly organized fibers while SHG can image the collagen fiber organization with high resolution. Articular cartilage, with abundant structural collagen fibers, is a suitable sample to study the correlation between PS-OCT and SHG microscopy. Qualitative conjecture has been made that the phase retardation measured by PS-OCT is affected by the relationship between the collagen fiber orientation and the illumination direction. Anatomical studies show that the multilayered architecture of articular cartilage can be divided into four zones from its natural surface to the subchondral bone: the superficial zone, the middle zone, the deep zone, and the calcified zone. The different zones have different collagen fiber orientations, which can be studied by the different slopes in the cumulative phase retardation in PS-OCT. An algorithm is developed based on the quantitative analysis of PS-OCT phase retardation images to analyze the microstructural features in swine articular cartilage tissues. This algorithm utilizes the depth-dependent slope changing of phase retardation A-lines to segment structural layers. The results show good consistency with the knowledge of cartilage morphology and correlation with the SHG images measured at selected depth locations. The correlation between PS-OCT and SHG microscopy shows that PS-OCT has the potential to analyze both the macro and micro characteristics of biological tissues with abundant collagen fibers and other materials that may cause birefringence.

  6. Regional Articular Cartilage Abnormalities of the Hip. (United States)

    Link, Thomas M; Schwaiger, Benedikt J; Zhang, Alan L


    Imaging of hip cartilage is challenging because of its limited thickness and complex geometry and therefore requires advanced MRI techniques. However, cartilage abnormalities are found in a number of disease entities, and their diagnosis may impact patient management. This article will provide pertinent information about the motivation to image hip cartilage, which imaging techniques to use, and how to analyze cartilage; finally, we will discuss disease entities with regional cartilage lesions, including the typical MRI findings. Because the detection and quantification of regional cartilage abnormalities are critical for guidance of operative and nonoperative management of hip disorders, radiologists should be familiar with imaging and analysis techniques for assessing hip cartilage.

  7. Mesenchymal Stem Cells for Cartilage Regeneration of TMJ Osteoarthritis

    Directory of Open Access Journals (Sweden)

    Dixin Cui


    Full Text Available Temporomandibular joint osteoarthritis (TMJ OA is a degenerative disease, characterized by progressive cartilage degradation, subchondral bone remodeling, synovitis, and chronic pain. Due to the limited self-healing capacity in condylar cartilage, traditional clinical treatments have limited symptom-modifying and structure-modifying effects to restore impaired cartilage as well as other TMJ tissues. In recent years, stem cell-based therapy has raised much attention as an alternative approach towards tissue repair and regeneration. Mesenchymal stem cells (MSCs, derived from the bone marrow, synovium, and even umbilical cord, play a role as seed cells for the cartilage regeneration of TMJ OA. MSCs possess multilineage differentiation potential, including chondrogenic differentiation as well as osteogenic differentiation. In addition, the trophic modulations of MSCs exert anti-inflammatory and immunomodulatory effects under aberrant conditions. Furthermore, MSCs combined with appropriate scaffolds can form cartilaginous or even osseous compartments to repair damaged tissue and impaired function of TMJ. In this review, we will briefly discuss the pathogenesis of cartilage degeneration in TMJ OA and emphasize the potential sources of MSCs and novel approaches for the cartilage regeneration of TMJ OA, particularly focusing on the MSC-based therapy and tissue engineering.

  8. Surface structure of polymer Gels and emerging functions

    CERN Document Server

    Kobiki, Y


    We report the surface structure of polymer gels on a submicrometer scale during the volume phase transition. Sponge-like domains with a mesoscopic scale were directly observed in water by using at atomic force microscope (AFM). The surface structure characterized by the domains is discussed in terms of the root-mean-square roughness and the auto-correlation function, which were calculated from the AFM images. In order to demonstrate the role of surface structure in determining the macroscopic properties of film-like poly (N-isopropylacrylamide: NIPA) gels. It was found that the temperature dependence, as well as the absolute values of the static contact angle, were strongly dependent on the bulk network inhomogeneities. The relation between the mesoscopic structure and the macroscopic properties is qualitatively discussed in terms of not only the changes in the chemical, but also in the physical, surface properties of the NIPA gels in response to a temperature change.

  9. Domain Structures in Nematic Liquid Crystals on a Polycarbonate Surface

    Directory of Open Access Journals (Sweden)

    Vasily F. Shabanov


    Full Text Available Alignment of nematic liquid crystals on polycarbonate films obtained with the use of solvents with different solvations is studied. Domain structures occurring during the growth on the polymer surface against the background of the initial thread-like or schlieren texture are demonstrated. It is established by optical methods that the domains are stable formations visualizing the polymer surface structures. In nematic droplets, the temperature-induced transition from the domain structure with two extinction bands to the structure with four bands is observed. This transition is shown to be caused by reorientation of the nematic director in the liquid crystal volume from the planar alignment to the homeotropic state with the pronounced radial configuration of nematic molecules on the surface. The observed textures are compared with different combinations of the volume LC orientations and the radial distribution of the director field and the disclination lines at the polycarbonate surface.

  10. Electronic structure of disordered alloys, surfaces and interfaces

    CERN Document Server

    Turek, Ilja; Kudrnovský, Josef; Šob, Mojmír; Weinberger, Peter


    At present, there is an increasing interest in the prediction of properties of classical and new materials such as substitutional alloys, their surfaces, and metallic or semiconductor multilayers. A detailed understanding based on a thus of the utmost importance for fu­ microscopic, parameter-free approach is ture developments in solid state physics and materials science. The interrela­ tion between electronic and structural properties at surfaces plays a key role for a microscopic understanding of phenomena as diverse as catalysis, corrosion, chemisorption and crystal growth. Remarkable progress has been made in the past 10-15 years in the understand­ ing of behavior of ideal crystals and their surfaces by relating their properties to the underlying electronic structure as determined from the first principles. Similar studies of complex systems like imperfect surfaces, interfaces, and mul­ tilayered structures seem to be accessible by now. Conventional band-structure methods, however, are of limited use ...

  11. Simulation of the surface structure of lithium manganese oxide spinel.

    Energy Technology Data Exchange (ETDEWEB)

    Benedek, R.; Thackeray, M. M. (Chemical Sciences and Engineering Division)


    Simulations of the surface structure of low-index surfaces of LiMn{sub 2}O{sub 4} (LMO), a candidate Li-ion battery electrode material, have been performed within the GGA+U approximation, using the VASP code. Surfaces of (001), (110), and (111) orientation were considered, with at least two terminations treated in each case. A slab geometry was employed, with termination-layer vacancies introduced to remove the bulk dipole moment while maintaining ideal stoichiometry. To complement static-structure relaxation calculations, molecular-dynamics simulations were performed to explore the phase space of possible surface reconstructions. A reconstruction is predicted for the Mn-terminated (111) surface, in which the top layers mix in stoichiometric proportions to form an LMO termination layer with square-planar-coordinated Mn. Average surface Mn oxidation states are reduced, relative to the bulk, for all surfaces considered, as a consequence of the lower-energy cost of Jahn-Teller distortion at the surface. Threefold-coordinated surface Mn, found for two terminations, is divalent, which may enhance its vulnerability to dissolution. The Li-terminated (001) surface is lowest in energy, consistent with previous classical-potential simulations for MgAl{sub 2}O{sub 4} that showed the Mg-terminated (001) surface to be lowest in energy.

  12. Simulation of the surface structure of lithium manganese oxide spinel (United States)

    Benedek, R.; Thackeray, M. M.


    Simulations of the surface structure of low-index surfaces of LiMn2O4 (LMO), a candidate Li-ion battery electrode material, have been performed within the GGA+U approximation, using the VASP code. Surfaces of (001), (110), and (111) orientation were considered, with at least two terminations treated in each case. A slab geometry was employed, with termination-layer vacancies introduced to remove the bulk dipole moment while maintaining ideal stoichiometry. To complement static-structure relaxation calculations, molecular-dynamics simulations were performed to explore the phase space of possible surface reconstructions. A reconstruction is predicted for the Mn-terminated (111) surface, in which the top layers mix in stoichiometric proportions to form an LMO termination layer with square-planar-coordinated Mn. Average surface Mn oxidation states are reduced, relative to the bulk, for all surfaces considered, as a consequence of the lower-energy cost of Jahn-Teller distortion at the surface. Threefold-coordinated surface Mn, found for two terminations, is divalent, which may enhance its vulnerability to dissolution. The Li-terminated (001) surface is lowest in energy, consistent with previous classical-potential simulations for MgAl2O4 that showed the Mg-terminated (001) surface to be lowest in energy.

  13. Dimers on Surface Graphs and Spin Structures. I

    DEFF Research Database (Denmark)

    Cimasoni, David; Reshetikhin, Nicolai


    Partition functions for dimers on closed oriented surfaces are known to be alternating sums of Pfaffians of Kasteleyn matrices. In this paper, we obtain the formula for the coefficients in terms of discrete spin structures.......Partition functions for dimers on closed oriented surfaces are known to be alternating sums of Pfaffians of Kasteleyn matrices. In this paper, we obtain the formula for the coefficients in terms of discrete spin structures....

  14. Surface structure of coherently strained ceria ultrathin films (United States)

    Shi, Yezhou; Stone, Kevin H.; Guan, Zixuan; Monti, Matteo; Cao, Chuntian; El Gabaly, Farid; Chueh, William C.; Toney, Michael F.


    Cerium oxide, or ceria, is an important material for solid oxide fuel cells and water splitting devices. Although the ceria surface is active in catalytic and electrochemical reactions, how its catalytic properties are affected by the surface structure under operating conditions is far from understood. We investigate the structure of the coherently strained Ce O2 ultrathin films on yttria-stabilized zirconia (001) single crystals by specular synchrotron x-ray diffraction (XRD) under oxidizing conditions as a first step to study the surface structure in situ. An excellent agreement between the experiment data and the model is achieved by using a "stacks and islands" model that has a two-component roughness. One component is due to the tiny clusters of nanometer scale in lateral dimensions on each terrace, while the other component is due to slightly different Ce O2 thickness that span over hundreds of nanometers on neighboring terraces. We attribute the nonuniform thickness to step depairing during the thin film deposition that is supported by the surface morphology results on the microscopic level. Importantly, our model also shows that the polarity of the ceria surface is removed by a half monolayer surface coverage of oxygen. The successful resolution of the ceria surface structure using in situ specular synchrotron XRD paves the way to study the structural evolution of ceria as a fuel cell electrode under catalytically relevant temperatures and gas pressures.

  15. Laser-induced nanoscale superhydrophobic structures on metal surfaces

    NARCIS (Netherlands)

    Radhakrishnan, J.; Pathiraj, B.; Karatay, Elif; Römer, Gerardus Richardus, Bernardus, Engelina; Huis in 't Veld, Bert


    The combination of a dual-scale (nano and micro) roughness with an inherent low-surface energy coating material is an essential factor for the development of superhydrophobic surfaces. Ultrashort pulse laser (USPL) machining/structuring is a promising technique for obtaining the dual-scale

  16. Ultrastructure of calcified cartilage in the endoskeletal tesserae of sharks. (United States)

    Kemp, N E; Westrin, S K


    The tesserate pattern of endoskeletal calcification has been investigated in jaws, gill arches, vertebral arches and fins of the sharks Carcharhinus menisorrah, Triaenodon obesus and Negaprion brevirostris by techniques of light and electron microscopy. Individual tesserae develop peripherally at the boundary between cartilage and perichondrium. An inner zone, the body, is composed of calcified cartilage containing viable chondroxytes separated by basophilic contour lines which have been called Liesegang waves or rings. The outer zone of tesserae, the cap, is composed of calcified tissue which appears to be produced by perichondrial fibroblasts more directly, i.e., without first differentiating as chondroblasts. Furthermore, the cap zone is penetrated by acidophilic Sharpey fibers of collagen. It is suggested that scleroblasts of the cap zone could be classified as osteoblasts. If so, the cap could be considered a thin veneer of bone atop the calcified cartilage of the body of a tessera. By scanning electron microscopy it was observed that outer and inner surfaces of tesserae differ in appearance. Calcospherites and hydroxyapatite crystals similar to those commonly seen on the surface of bone are present on the outer surface of the tessera adjacent to the perichondrium. On the inner surface adjoining hyaline cartilage, however, calcospherites of variable size are the predominant surface feature. Transmission electron microscopy shows calcification in close association with coarse collagen fibrils on the outer side of a tessera, but such fibrils are absent from the cartilaginous matrix along the under side of tesserae. Calcified cartilage as a tissue type in the endoskeleton of sharks is a primitive vertebrate characteristic. Calcification in the tesserate pattern occurring in modern Chondrichthyes may be derived from an ancestral pattern of a continuous bed of calcified cartilage underlying a layer of perichondral bone, as theorized by Orvig ('51); or the tesserate

  17. Structures of multidomain proteins adsorbed on hydrophobic interaction chromatography surfaces. (United States)

    Gospodarek, Adrian M; Sun, Weitong; O'Connell, John P; Fernandez, Erik J


    In hydrophobic interaction chromatography (HIC), interactions between buried hydrophobic residues and HIC surfaces can cause conformational changes that interfere with separations and cause yield losses. This paper extends our previous investigations of protein unfolding in HIC chromatography by identifying protein structures on HIC surfaces under denaturing conditions and relating them to solution behavior. The thermal unfolding of three model multidomain proteins on three HIC surfaces of differing hydrophobicities was investigated with hydrogen exchange mass spectrometry (HXMS). The data were analyzed to obtain unfolding rates and Gibbs free energies for unfolding of adsorbed proteins. The melting temperatures of the proteins were lowered, but by different amounts, on the different surfaces. In addition, the structures of the proteins on the chromatographic surfaces were similar to the partially unfolded structures produced in the absence of a surface by temperature as well as by chemical denaturants. Finally, it was found that patterns of residue exposure to solvent on different surfaces at different temperatures can be largely superimposed. These findings suggest that protein unfolding on various HIC surfaces might be quantitatively related to protein unfolding in solution and that details of surface unfolding behavior might be generalized. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Full-Length Recombinant Human Proteoglycan 4 Interacts with Hyaluronan to Provide Cartilage Boundary Lubrication. (United States)

    Abubacker, Saleem; Dorosz, Samuel G; Ponjevic, Dragana; Jay, Gregory D; Matyas, John R; Schmidt, Tannin A


    Proteoglycan 4 (PRG4) is a mucin-like glycoprotein present in synovial fluid and at the surface of articular cartilage. The objectives of this study were to (1) assess the articular cartilage surface adsorption and in vitro cartilage boundary lubricating ability of full-length recombinant human PRG4 (rhPRG4), and (2) cartilage boundary lubricating ability of purified rhPRG4, both alone and in combination with hyaluronan (HA). rhPRG4 adsorption onto articular cartilage explants was assessed by immunohistochemistry and dot blot. An in vitro cartilage-cartilage friction test was used to assess rhPRG4's cartilage boundary lubricating ability compared to bovine PRG4, and that of purified rhPRG4 both alone and in combination with HA. rhPRG4 was able to adsorb to the articular surface, as well as the cut surface, of cartilage explants. The kinetic coefficient of friction of rhPRG4 was similar to that of PRG4 (p = 0.16) and lower than phosphate-buffered saline (p < 0.05), while that of purified rhPRG4 + HA was significantly lower than rhPRG4 alone (p < 0.05). This study demonstrates that rhPRG4 can adsorb to an intact articular cartilage surface and functions as an effective boundary lubricant, both alone and with HA, and provides the foundation for in vivo evaluation of this clinically relevant full-length rhPRG4 for treatment of osteoarthritis.

  19. Color effects from scattering on random surface structures in dielectrics

    DEFF Research Database (Denmark)

    Clausen, Jeppe; Christiansen, Alexander B; Garnæs, Jørgen


    We show that cheap large area color filters, based on surface scattering, can be fabricated in dielectric materials by replication of random structures in silicon. The specular transmittance of three different types of structures, corresponding to three different colors, have been characterized...

  20. Numerical simulations of drop impact on superhydrophobic structured surfaces (United States)

    Guzzetti, Davide; Larentis, Stefano; Pugno, Nicola


    During the last decade drop impact dynamics on superhydrophobic surfaces has been intensively investigated because of the incredible properties of water repellency exhibited by this kind of surfaces, mostly inspired by biological examples such as Lotus leave. Thanks to the recent progress in micro-fabrication technology is possible to tailor surfaces wettability defining specific pillar-like structured surfaces. In this work, the behavior of impinging drops on these pillar-like surfaces is simulated, characterizing temporal evolution of droplets contact radius and drop maximal deformation dependence on Weber number. Numerical simulations results are compared with theoretical and experimental results guaranteeing simulation reliability. Fingering patterns obtained from drop impact has been studied obtaining a correlation between number of fingers and Weber number. Drop fragmentation pattern obtained from simulations supports the proposed correlation. Different drop impact outcomes (e.g. rebound, fragmentation) on structured superhydrophobic surfaces are simulated, focusing on the influence of micro-structured surface geometrical pattern. This investigation is relevant in order to define design rules for possible reliable non wettable surfaces. Financial support by Alta Scuola Politecnica.

  1. Delayed Gadolinium-Enhanced MRI of Cartilage (dGEMRIC) of Cadaveric Shoulders: Comparison of Contrast Dynamics in Hyaline and Fibrous Cartilage after Intraarticular Gadolinium Injection

    Energy Technology Data Exchange (ETDEWEB)

    Wiener, E. (Dept. of Radiology, Charite Universitaetsmedizin Berlin (Germany)); Hodler, J.; Pfirrmann, C.W.A. (Dept. of Radiology, Orthopedic Univ. Hospital Balgrist, Zuerich (Switzerland))


    Background: Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is a novel method to investigate cartilaginous and fibrocartilaginous structures. Purpose: To investigate the contrast dynamics in hyaline and fibrous cartilage of the glenohumeral joint after intraarticular injection of gadopentetate dimeglumine. Material and Methods: Transverse T1 maps were acquired on a 1.5T scanner before and after intraarticular injection of 2.0 mmol/l gadopentetate dimeglumine in five cadaveric shoulders using a dual flip angle three-dimensional gradient echo (3D-GRE) sequence. The acquisition time for the T1 maps was 5 min 5 s for the whole shoulder. Measurements were repeated every 15 min over 2.5 hours. Regions of interest (ROIs) covering the glenoid cartilage and the labrum were drawn to assess the temporal evolution of the relaxation parameters. Results: T1 of unenhanced hyaline cartilage of the glenoid was 568+-34 ms. T1 of unenhanced fibrous cartilage of the labrum was 552+-38 ms. Significant differences (P=0.002 and 0.03) in the relaxation parameters were already measurable after 15 min. After 2 to 2.5 hours, hyaline and fibrous cartilage still demonstrated decreasing relaxation parameters, with a larger range of the T1(Gd) values in fibrous cartilage. T1 and ?R1 values of hyaline and fibrous cartilage after 2.5 hours were 351+-16 ms and 1.1+-0.09/s, and 332+-31 ms and 1.2+-0.1/s, respectively. Conclusion: A significant decrease in T1(Gd) was found 15 min after intraarticular contrast injection. Contrast accumulation was faster in hyaline than in fibrous cartilage. After 2.5 hours, contrast accumulation showed a higher rate of decrease in hyaline cartilage, but neither hyaline nor fibrous cartilage had reached equilibrium

  2. Surface Monitoring of CFRP Structures for Adhesive Bonding (United States)

    Ledesma, Rodolfo; Palmieri, Frank L.; Yost, William T.; Connell, John W.; Fitz-Gerald, James M.


    Adhesive bonding of composite materials requires reliable monitoring and detection of surface contaminants to assure robust and durable bonded structures. Surface treatment and effective monitoring prior to bonding is essential in order to obtain a surface free from contaminants that may degrade structural performance. Two techniques which monitor the effectiveness of the laser surface treatment of carbon fiber reinforced polymer (CFRP) materials are being investigated: laser induced breakdown spectroscopy (LIBS) and optically stimulated electron emission (OSEE). The applicability of LIBS to detect silicone contaminants on CFRP composites is studied using 35 ns Nd:YAG laser pulses at 355 nm with a pulse energy of 45 mJ. The LIBS regime in which pulse energies are treatment by laser ablation on specimens contaminated with PDMS coatings from 8 nm to 1311 nm in thickness. The results showed a significant increase in the OSEE photocurrent after laser surface treatment.

  3. Effect of silver nanoparticles and hydroxyproline, administered in ovo, on the development of blood vessels and cartilage collagen structure in chicken embryos

    DEFF Research Database (Denmark)

    Beck, Iwona; Hotowy, Anna; Sawosz, Ewa


    . Experiments were performed on Ross 308 chicken embryos from 160 fertilised eggs. Experimental solutions of silver nanoparticles (Ag), hydroxyproline solution (Hyp) and a complex of silver nanoparticles with hydroxyproline (AgHyp) were injected into albumen, and embryos were incubated until day 20...... microscopy was performed. Our results clearly indicate that Hyp, Ag and AgHyp administered in ovo to chicken embryos did not harm embryos. Comparing to the control group, Hyp, Ag and the AgHyp complex significantly upregulated expression of the FGF-2 at the mRNA and protein levels. Moreover, Hyp, Ag and......, in particular, the complex of AgHyp significantly increased blood vessel size, cartilage collagen fibre lattice size and bundle thickness. The general conclusion from this study is that AgHyp treatment may help to build a stronger and longer lasting form of collagen fibres....

  4. A genetic algorithm approach in interface and surface structure optimization

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jian [Iowa State Univ., Ames, IA (United States)


    The thesis is divided into two parts. In the first part a global optimization method is developed for the interface and surface structures optimization. Two prototype systems are chosen to be studied. One is Si[001] symmetric tilted grain boundaries and the other is Ag/Au induced Si(111) surface. It is found that Genetic Algorithm is very efficient in finding lowest energy structures in both cases. Not only existing structures in the experiments can be reproduced, but also many new structures can be predicted using Genetic Algorithm. Thus it is shown that Genetic Algorithm is a extremely powerful tool for the material structures predictions. The second part of the thesis is devoted to the explanation of an experimental observation of thermal radiation from three-dimensional tungsten photonic crystal structures. The experimental results seems astounding and confusing, yet the theoretical models in the paper revealed the physics insight behind the phenomena and can well reproduced the experimental results.

  5. Formation of Surface Corrosion-Resistant Nanocrystalline Structures on Steel (United States)

    Nykyforchyn, Hryhoriy; Kyryliv, Volodymyr; Maksymiv, Olha; Slobodyan, Zvenomyra; Tsyrulnyk, Oleksandr


    Engineering materials with nanocrystalline structure could be exploited under simultaneous action of mechanical loading and corrosion environments; therefore, their corrosion resistance is important. Surface nanocrystalline structure was generated on middle carbon steels by severe plastic deformation using the method of mechanical pulse friction treatment. This treatment additionally includes high temperature phase transformation and alloying. Using a complex of the corrosive, electrochemical and physical investigations, it was established that nanocrystalline structures can be characterized by lower or increased corrosion resistance in comparison with the reference material. It is caused by the action of two confronting factors: arising energy level and anticorrosive alloying of the surface layer.

  6. Sliding surface searching method for slopes containing a potential weak structural surface

    Directory of Open Access Journals (Sweden)

    Aijun Yao


    Full Text Available Weak structural surface is one of the key factors controlling the stability of slopes. The stability of rock slopes is in general concerned with set of discontinuities. However, in soft rocks, failure can occur along surfaces approaching to a circular failure surface. To better understand the position of potential sliding surface, a new method called simplex-finite stochastic tracking method is proposed. This method basically divides sliding surface into two parts: one is described by smooth curve obtained by random searching, the other one is polyline formed by the weak structural surface. Single or multiple sliding surfaces can be considered, and consequently several types of combined sliding surfaces can be simulated. The paper will adopt the arc-polyline to simulate potential sliding surface and analyze the searching process of sliding surface. Accordingly, software for slope stability analysis using this method was developed and applied in real cases. The results show that, using simplex-finite stochastic tracking method, it is possible to locate the position of a potential sliding surface in the slope.

  7. Accuracy of magnetic resonance imaging to detect cartilage loss in severe osteoarthritis of the first carpometacarpal joint: comparison with histological evaluation. (United States)

    Saltzherr, Michael S; Coert, J Henk; Selles, Ruud W; van Neck, Johan W; Jaquet, Jean-Bart; van Osch, Gerjo J V M; Oei, Edwin H G; Luime, Jolanda J; Muradin, Galied S R


    Magnetic resonance imaging (MRI) is increasingly used for research in hand osteoarthritis, but imaging the thin cartilage layers in the hand joints remains challenging. We therefore assessed the accuracy of MRI in detecting cartilage loss in patients with symptomatic osteoarthritis of the first carpometacarpal (CMC1) joint. Twelve patients scheduled for trapeziectomy to treat severe symptomatic osteoarthritis of the CMC1 joint underwent a preoperative high resolution 3D spoiled gradient (SPGR) MRI scan. Subsequently, the resected trapezium was evaluated histologically. The sections were scored for cartilage damage severity (Osteoarthritis Research Society International (OARSI) score), and extent of damage (percentage surface area). Each MRI scan was scored for the area of normal cartilage, partial cartilage loss and full cartilage loss. The percentages of the total surface area with any cartilage loss and full-thickness cartilage loss were calculated using MRI and histological evaluation. MRI and histological evaluation both identified large areas of overall cartilage loss. The median (IQR) surface area of any cartilage loss on MRI was 98% (82-100%), and on histological assessment 96% (87-98%). However, MRI underestimated the extent of full-thickness cartilage loss. The median (IQR) surface area of full-thickness cartilage loss on MRI was 43% (22-70%), and on histological evaluation 79% (67-85%). The difference was caused by a thin layer of high signal on the articulating surface, which was interpreted as damaged cartilage on MRI but which was not identified on histological evaluation. Three-dimensional SPGR MRI of the CMC1 joint demonstrates overall cartilage damage, but underestimates full-thickness cartilage loss in patients with advanced osteoarthritis.

  8. Scale-adaptive surface modeling of vascular structures

    Directory of Open Access Journals (Sweden)

    Ma Xin


    Full Text Available Abstract Background The effective geometric modeling of vascular structures is crucial for diagnosis, therapy planning and medical education. These applications require good balance with respect to surface smoothness, surface accuracy, triangle quality and surface size. Methods Our method first extracts the vascular boundary voxels from the segmentation result, and utilizes these voxels to build a three-dimensional (3D point cloud whose normal vectors are estimated via covariance analysis. Then a 3D implicit indicator function is computed from the oriented 3D point cloud by solving a Poisson equation. Finally the vessel surface is generated by a proposed adaptive polygonization algorithm for explicit 3D visualization. Results Experiments carried out on several typical vascular structures demonstrate that the presented method yields both a smooth morphologically correct and a topologically preserved two-manifold surface, which is scale-adaptive to the local curvature of the surface. Furthermore, the presented method produces fewer and better-shaped triangles with satisfactory surface quality and accuracy. Conclusions Compared to other state-of-the-art approaches, our method reaches good balance in terms of smoothness, accuracy, triangle quality and surface size. The vessel surfaces produced by our method are suitable for applications such as computational fluid dynamics simulations and real-time virtual interventional surgery.

  9. Glucose Gradients Influence Zonal Matrix Deposition in 3D Cartilage Constructs

    NARCIS (Netherlands)

    Spitters, T.W.; Mota, C.M.D.; Uzoechi, S.C.; Slowinska, B.; Martens, D.E.; Moroni, L.; Karperien, M.


    Reproducing the native collagen structure and glycosaminoglycan (GAG) distribution in tissue-engineered cartilage constructs is still a challenge. Articular cartilage has a specific nutrient supply and mechanical environment due to its location and function in the body. Efforts to simulate this

  10. Atomic structure of the SbCu surface alloy: A surface X-ray diffraction study

    DEFF Research Database (Denmark)

    Meunier, I.; Gay, J.M.; Lapena, L.


    The dissolution at 400 degrees C of an antimony layer deposited at room temperature on a Cu(111) substrate leads to a surface alloy with a p(root 3x root 3)R 30 degrees x 30 degrees superstructure and a Sb composition of 1/3.We present here a structural study of this Sb-Cu compound by surface X...

  11. Protein structural perturbation and aggregation on homogeneous surfaces. (United States)

    Sethuraman, Ananthakrishnan; Belfort, Georges


    We have demonstrated that globular proteins, such as hen egg lysozyme in phosphate buffered saline at room temperature, lose native structural stability and activity when adsorbed onto well-defined homogeneous solid surfaces. This structural loss is evident by alpha-helix to turns/random during the first 30 min and followed by a slow alpha-helix to beta-sheet transition. Increase in intramolecular and intermolecular beta-sheet content suggests conformational rearrangement and aggregation between different protein molecules, respectively. Amide I band attenuated total reflection/Fourier transformed infrared (ATR/FTIR) spectroscopy was used to quantify the secondary structure content of lysozyme adsorbed on six different self-assembled alkanethiol monolayer surfaces with -CH3, -OPh, -CF3, -CN, -OCH3, and -OH exposed functional end groups. Activity measurements of adsorbed lysozyme were in good agreement with the structural perturbations. Both surface chemistry (type of functional groups, wettability) and adsorbate concentration (i.e., lateral interactions) are responsible for the observed structural changes during adsorption. A kinetic model is proposed to describe secondary structural changes that occur in two dynamic phases. The results presented in this article demonstrate the utility of the ATR/FTIR spectroscopic technique for in situ characterization of protein secondary structures during adsorption on flat surfaces.

  12. Superhydrophobicity of biological and technical surfaces under moisture condensation: stability in relation to surface structure. (United States)

    Mockenhaupt, Bernd; Ensikat, Hans-Jürgen; Spaeth, Manuel; Barthlott, Wilhelm


    The stability of superhydrophobic properties of eight plants and four technical surfaces in respect to water condensation has been compared. Contact and sliding angles were measured after application of water drops of ambient temperature (20 degrees C) onto cooled surfaces. Water evaporating from the drops condensed, due to the temperature difference between the drops and the surface, on the cooled samples, forming "satellite droplets" in the vicinity of the drops. Surface cooling to 15, 10, and 5 degrees C showed a gradual decrease of superhydrophobicity. The decrease was dependent on the specific surface architecture of the sample. The least decrease was found on hierarchically structured surfaces with a combination of a coarse microstructure and submicrometer-sized structures, similar to that of the Lotus leaf. Control experiments with glycerol droplets, which show no evaporation, and thus no condensation, were carried out to verify that the effects with water were caused by condensation from the drop (secondary condensation). Furthermore, the superhydrophobic properties after condensation on cooled surfaces from a humid environment for 10 min were examined. After this period, the surfaces were covered with spherical water droplets, but most samples retained their superhydrophobicity. Again, the best stability of the water-repellent properties was found on hierarchically structured surfaces similar to that of the Lotus leaf.

  13. Phase structure of a surface model with many fine holes. (United States)

    Koibuchi, H


    We study the phase structure of a surface model by using the canonical Monte Carlo simulation technique on triangulated, fixed connectivity, and spherical surfaces with many fine holes. The size of a hole is assumed to be of the order of lattice spacing (or bond length) and hence can be negligible compared to the surface size in the thermodynamic limit. We observe in the numerical data that the model undergoes a first-order collapsing transition between the smooth phase and the collapsed phase. Moreover the Hasudorff dimension H remains in the physical bound, i.e., H model in this paper and the previous one with many holes, whose size is of the order of the surface size, because the previous surface model with large-sized holes has only the collapsing transition and no transition of surface fluctuations.

  14. SurfCut: Surfaces of Minimal Paths From Topological Structures

    KAUST Repository

    Algarni, Marei Saeed Mohammed


    We present SurfCut, an algorithm for extracting a smooth, simple surface with an unknown 3D curve boundary from a noisy 3D image and a seed point. Our method is built on the novel observation that certain ridge curves of a function defined on a front propagated using the Fast Marching algorithm lie on the surface. Our method extracts and cuts these ridges to form the surface boundary. Our surface extraction algorithm is built on the novel observation that the surface lies in a valley of the distance from Fast Marching. We show that the resulting surface is a collection of minimal paths. Using the framework of cubical complexes and Morse theory, we design algorithms to extract these critical structures robustly. Experiments on three 3D datasets show the robustness of our method, and that it achieves higher accuracy with lower computational cost than state-of-the-art.

  15. Cartilage tissue engineering: From biomaterials and stem cells to osteoarthritis treatments. (United States)

    Vinatier, C; Guicheux, J


    Articular cartilage is a non-vascularized and poorly cellularized connective tissue that is frequently damaged as a result of trauma and degenerative joint diseases such as osteoarthrtis. Because of the absence of vascularization, articular cartilage has low capacity for spontaneous repair. Today, and despite a large number of preclinical data, no therapy capable of restoring the healthy structure and function of damaged articular cartilage is clinically available. Tissue-engineering strategies involving the combination of cells, scaffolding biomaterials and bioactive agents have been of interest notably for the repair of damaged articular cartilage. During the last 30 years, cartilage tissue engineering has evolved from the treatment of focal lesions of articular cartilage to the development of strategies targeting the osteoarthritis process. In this review, we focus on the different aspects of tissue engineering applied to cartilage engineering. We first discuss cells, biomaterials and biological or environmental factors instrumental to the development of cartilage tissue engineering, then review the potential development of cartilage engineering strategies targeting new emerging pathogenic mechanisms of osteoarthritis. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  16. Understanding surface structure and chemistry of single crystal lanthanum aluminate

    KAUST Repository

    Pramana, Stevin S.


    The surface crystallography and chemistry of a LaAlO3 single crystal, a material mainly used as a substrate to deposit technologically important thin films (e.g. for superconducting and magnetic devices), was analysed using surface X-ray diffraction and low energy ion scattering spectroscopy. The surface was determined to be terminated by Al-O species, and was significantly different from the idealised bulk structure. Termination reversal was not observed at higher temperature (600 °C) and chamber pressure of 10−10 Torr, but rather an increased Al-O occupancy occurred, which was accompanied by a larger outwards relaxation of Al from the bulk positions. Changing the oxygen pressure to 10−6 Torr enriched the Al site occupancy fraction at the outermost surface from 0.245(10) to 0.325(9). In contrast the LaO, which is located at the next sub-surface atomic layer, showed no chemical enrichment and the structural relaxation was lower than for the top AlO2 layer. Knowledge of the surface structure will aid the understanding of how and which type of interface will be formed when LaAlO3 is used as a substrate as a function of temperature and pressure, and so lead to improved design of device structures.

  17. Treatment of knee cartilage defect in 2010. (United States)

    Versier, G; Dubrana, F


    Treatment of knee cartilage defect, a true challenge, should not only reconstruct hyaline cartilage on a long-term basis, but also be able to prevent osteoarthritis. Osteochondral knee lesions occur in either traumatic lesions or in osteochondritis dissecans (OCD). These lesions can involve all the articular surfaces of the knee in its three compartments. In principle, this review article covers symptomatic ICRS grade C or D lesions, depth III and IV, excluding management of superficial lesions, asymptomatic lesions that are often discovered unexpectedly, and kissing lesions, which arise prior to or during osteoarthritis. For clarity sake, the international classifications used are reviewed, for both functional assessment (ICRS and functional IKDC for osteochondral fractures, Hughston for osteochondritis) and morphological lesion evaluations (the ICRS macroscopic evaluation for fractures, the Bedouelle or SOFCOT for osteochondritis, and MOCART for MRI). The therapeutic armamentarium to treat these lesions is vast, but accessibility varies greatly depending on the country and the legislation in effect. Many comparative studies have been conducted, but they are rarely of high scientific quality; the center effect is nearly constant because patients are often referred to certain centers for an expert opinion. The indications defined herein use algorithms that take into account the size of the cartilage defect and the patient's functional needs for cases of fracture and the vitality, stability, and size of the fragment for cases of osteochondritis dissecans. Fractures measuring less than 2 cm(2) are treated with either microfracturing or mosaic osteochondral grafting, between 2 and 4 cm(2) with microfractures covered with a membrane or a culture of second- or third-generation chondrocytes, and beyond this size, giant lesions are subject to an exceptional allografting procedure, harvesting from the posterior condyle, or chondrocyte culture on a 3D matrix to restore

  18. Articular calcified cartilage canals in the third metacarpal bone of 2-year-old thoroughbred racehorses (United States)

    Boyde, A; Firth, E C


    We describe morphological aspects of the articular calcified cartilage mineralizing front ‘tidemark’ in the distal joint surface of the third metacarpal bone from 14 horses. Compositional backscattered electron scanning electron microscopy and confocal scanning light microscopy were conducted on polymethylmethacrylate (PMMA)-embedded medio-lateral slices. After maceration, scanning electron microscopy (SEM) was used to study the calcified cartilage surface in the ‘wedges’ intervening between the slices. An anatomically reproducible clustering of canals in the calcified cartilage was found at one site on the sagittal ridge in all the horses. The site is one that is relatively less loaded during joint function. These canals through calcified cartilage result from osteoclastic resorption (cutting cones) penetrating from bone through to the non-mineralized hyaline articular cartilage. Their presence may indicate a pathway for connection between bone and cartilage extracellular fluid. In one horse, repair of such canals by plugging with new calcified cartilage was demonstrated. Differences in the degree of mineralization of regions of cartilage were seen in the combined compositional-cum-topographical backscattered SEM images of the macerated ‘tidemark’ front. More-or-less circular patches of lower mineralization density were frequently centred on (and may possibly originate from) canals. These microanatomical features should be searched for in other joints, at other ages and in other species to discover their frequency and significance. PMID:15610396

  19. Patellar articular cartilage lesions: in vitro MR imaging evaluation after placement in gadopentetate dimeglumine solution. (United States)

    Woertler, Klaus; Buerger, Horst; Moeller, Jens; Rummeny, Ernst J


    To evaluate T1-weighted magnetic resonance (MR) imaging after diffusion of gadopentetate dimeglumine for visualization of articular cartilage lesions. MR imaging was performed in eight human cadaveric patella specimens immediately and 4 hours after placement into a vessel filled with gadopentetate dimeglumine solution (2.5 mmol/L). T1-weighted spin-echo and inversion-recovery turbo spin-echo MR sequences with nulled cartilage signal (inversion time of 300 msec) were used. In a total of 128 articular cartilage areas, MR imaging findings were compared with macroscopic and histopathologic findings. Pathologic evaluation was performed by one musculoskeletal pathologist. With knowledge of pathologic observations, MR images were analyzed by one musculoskeletal radiologist with regard to intrinsic signal intensity characteristics and surface abnormalities of articular cartilage. Histopathologic findings demonstrated 67 areas of normal articular cartilage and 66 cartilage lesions (grade 1, n = 19; grade 2, n = 15; grade 3, n = 26; grade 4, n = 6). All grade 3 and 4 lesions could be identified on MR images obtained immediately after submersion and after 4 hours. Ninety-four percent of grade 1 and 2 lesions were identified as areas of predominantly decreased contrast enhancement on delayed MR images obtained with both sequences. MR images obtained immediately after submersion demonstrated abnormal signal intensity in only 9% and 12% of grade 1 and 2 lesions, respectively. T1-weighted MR images obtained in vitro after gadopentetate dimeglumine diffusion allow demonstration of articular cartilage surface lesions and early stages of cartilage degradation. Copyright RSNA, 2004

  20. Condensation and Wetting Dynamics on Micro/Nano-Structured Surfaces (United States)

    Olceroglu, Emre

    Because of their adjustable wetting characteristics, micro/nanostructured surfaces are attractive for the enhancement of phase-change heat transfer where liquid-solid-vapor interactions are important. Condensation, evaporation, and boiling processes are traditionally used in a variety of applications including water harvesting, desalination, industrial power generation, HVAC, and thermal management systems. Although they have been studied by numerous researchers, there is currently a lack of understanding of the underlying mechanisms by which structured surfaces improve heat transfer during phase-change. This PhD dissertation focuses on condensation onto engineered surfaces including fabrication aspect, the physics of phase-change, and the operational limitations of engineered surfaces. While superhydrophobic condensation has been shown to produce high heat transfer rates, several critical issues remain in the field. These include surface manufacturability, heat transfer coefficient measurement limitations at low heat fluxes, failure due to surface flooding at high supersaturations, insufficient modeling of droplet growth rates, and the inherent issues associated with maintenance of non-wetted surface structures. Each of these issues is investigated in this thesis, leading to several contributions to the field of condensation on engineered surfaces. A variety of engineered surfaces have been fabricated and characterized, including nanostructured and hierarchically-structured superhydrophobic surfaces. The Tobacco mosaic virus (TMV) is used here as a biological template for the fabrication of nickel nanostructures, which are subsequently functionalized to achieve superhydrophobicity. This technique is simple and sustainable, and requires no applied heat or external power, thus making it easily extendable to a variety of common heat transfer materials and complex geometries. To measure heat transfer rates during superhydrophobic condensation in the presence of non

  1. Crystallography and surface structure an introduction for surface scientists and nanoscientists

    CERN Document Server

    Hermann, Klaus


    A valuable learning tool as well as a reference, this book provides students and researchers in surface science and nanoscience with the theoretical crystallographic foundations, which are necessary to understand local structure and symmetry of bulk crystals, including ideal and real single crystal surfaces. The author deals with the subject at an introductory level, providing numerous graphic examples to illustrate the mathematical formalism. The book brings together and logically connects many seemingly disparate structural issues and notations used frequently by surface scientists and nanoscientists. Numerous exercises of varying difficulty, ranging from simple questions to small research projects, are included to stimulate discussions about the different subjects.

  2. Surface and Core Electronic Structure of Oxidized Silicon Nanocrystals

    Directory of Open Access Journals (Sweden)

    Noor A. Nama


    Full Text Available Ab initio restricted Hartree-Fock method within the framework of large unit cell formalism is used to simulate silicon nanocrystals between 216 and 1000 atoms (1.6–2.65 nm in diameter that include Bravais and primitive cell multiples. The investigated properties include core and oxidized surface properties. Results revealed that electronic properties converge to some limit as the size of the nanocrystal increases. Increasing the size of the core of a nanocrystal resulted in an increase of the energy gap, valence band width, and cohesive energy. The lattice constant of the core and oxidized surface parts shows a decreasing trend as the nanocrystal increases in a size that converges to 5.28 Ǻ in a good agreement with the experiment. Surface and core convergence to the same lattice constant reflects good adherence of oxide layer at the surface. The core density of states shows highly degenerate states that split at the oxygenated (001-(1×1 surface due to symmetry breaking. The nanocrystal surface shows smaller gap and higher valence and conduction bands when compared to the core part, due to oxygen surface atoms and reduced structural symmetry. The smaller surface energy gap shows that energy gap of the nanocrystal is controlled by the surface part. Unlike the core part, the surface part shows a descending energy gap that proves its obedience to quantum confinement effects. Nanocrystal geometry proved to have some influence on all electronic properties including the energy gap.

  3. Laser Surface Preparation for Adhesive Bonding of Aerospace Structural Composites (United States)

    Belcher, M. A.; Wohl, C. J.; Hopkins, J. W.; Connell, J. W.


    Adhesive bonds are critical to the integrity of built-up structures. Disbonds can often be detected but the strength of adhesion between surfaces in contact is not obtainable without destructive testing. Typically the number one problem in a bonded structure is surface contamination, and by extension, surface preparation. Standard surface preparation techniques, including grit blasting, manual abrasion, and peel ply, are not ideal because of variations in their application. Etching of carbon fiber reinforced plastic (CFRP) panels using a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser appears to be a highly precise and promising way to both clean a composite surface prior to bonding and provide a bond-promoting patterned surface akin to peel ply without the inherent drawbacks from the same (i.e., debris and curvature). CFRP surfaces prepared using laser patterns conducive to adhesive bonding were compared to typical pre-bonding surface treatments through optical microscopy, contact angle goniometry, and post-bonding mechanical testing.

  4. Bioactive Nano-Fibrous Scaffolds for Bone and Cartilage Tissue Engineering (United States)

    Feng, Kai

    technique to support a more parallel ECM orientation to the cartilage surface. The lower layer was fabricated using a phase-separation technique to support a more isotropic ECM distribution. Human bone marrow-derived mesenchymal stem cells (hMSCs) were seeded on this complex scaffold and cultured under chondrogenic conditions. The results showed that the composite scaffold was indeed able to support anisotropic cartilage tissue structure formation.

  5. Injection of Compressed Diced Cartilage in the Correction of Secondary and Primary Rhinoplasty: A New Technique with 12 Years' Experience. (United States)

    Erol, O Onur


    There are instances where small or large pockets are filled with diced cartilage in the nose, without use of wrapping materials. For this purpose, 1-cc commercial syringes were used. The obtained results were partial and incomplete. For better and improved results, the author designed new syringes, with two different sizes, which compress the diced cartilage for injection. The author presents his experience accrued over the past 12 years with 2366 primary, 749 secondary, 67 cleft lip and nose, and a total of 3182 rhinoplasties, using his new syringe design, which compresses diced cartilage and injects the diced cartilages as a conglutinate mass, simulating carved costal cartilage, but a malleable one. In 3125 patients, the take of cartilage graft was complete (98.2 percent) and a smooth surface was obtained, giving them a natural appearance. In 21 patients (0.65 percent), there was partial resorption of cartilage. Correction was performed with touch-up surgery by reinjection of a small amount of diced cartilage. In 36 patients (1.13 percent), there was overcorrection that, 1 year later, was treated by simple rasping. Compared with diced cartilage wrapped with Surgicel or fascia, the amount of injected cartilage graft is predictable because it consists purely of cartilage. The injected diced cartilage, because it is compressed and becomes a conglutinated mass, resembles a wood chip and simulates carved cartilage. It is superior to carved cartilage in that it is moldable, time saving, and gives a good result with no late show or warping. The injection takes only a few minutes.

  6. Photonic structures in diamond based on femtosecond UV laser induced periodic surface structuring (LIPSS). (United States)

    Granados, Eduardo; Martinez-Calderon, Miguel; Gomez, Mikel; Rodriguez, Ainara; Olaizola, Santiago M


    We study the fabrication of photonic surface structures in single crystal diamond by means of highly controllable direct femtosecond UV laser induced periodic surface structuring. By appropriately selecting the excitation wavelength, intensity, number of impinging pulses and their polarization state, we demonstrate emerging high quality and fidelity diamond grating structures with surface roughness below 1.4 nm. We characterize their optical properties and study their potential for the fabrication of photonic structure anti-reflection coatings for diamond Raman lasers in the near-IR.

  7. Compact surface structures for the efficient excitation of surface plasmon-polaritons

    Energy Technology Data Exchange (ETDEWEB)

    De la Cruz, S.; Mendez, E.R. [Division de Fisica Applicada, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Carretera Ensenada-Tijuana No. 3918, Ensenada 22860, BC (Mexico); Macias, D.; Salas-Montiel, R.; Adam, P.M. [Laboratoire de Nanotechnologie et d' Instrumentation Optique, Universite de Technologie de Troyes, 12 rue Marie Curie, BP-2060, 10010 Troyes Cedex (France)


    We present calculations of the efficiency of excitation of surface plasmon-polaritons (SPPs) with surface structures illuminated by focussed beams. First, it is shown that the low reflectivity observed with broad highly directional beams and periodic gratings does not necessarily imply an efficient coupling to SPPs. We then consider the coupling through surface features like steps, grooves and angled steps, and calculate efficiency maps for these structures as functions of the parameters that define them. Finally, we explore the possibilities of improving the coupling efficiency using periodic structures consisting of a small number of rectangular grooves. We find that a surface section with a length of about four wavelengths can couple as much as 45% of the incident light into a directional SPP. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Sulfur-induced structural motifs on copper and gold surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Walen, Holly [Iowa State Univ., Ames, IA (United States)


    The interaction of sulfur with copper and gold surfaces plays a fundamental role in important phenomena that include coarsening of surface nanostructures, and self-assembly of alkanethiols. Here, we identify and analyze unique sulfur-induced structural motifs observed on the low-index surfaces of these two metals. We seek out these structures in an effort to better understand the fundamental interactions between these metals and sulfur that lends to the stability and favorability of metal-sulfur complexes vs. chemisorbed atomic sulfur. The experimental observations presented here—made under identical conditions—together with extensive DFT analyses, allow comparisons and insights into factors that favor the existence of metal-sulfur complexes, vs. chemisorbed atomic sulfur, on metal terraces. We believe this data will be instrumental in better understanding the complex phenomena occurring between the surfaces of coinage metals and sulfur.

  9. Robust biomimetic-structural superhydrophobic surface on aluminum alloy. (United States)

    Li, Lingjie; Huang, Tao; Lei, Jinglei; He, Jianxin; Qu, Linfeng; Huang, Peiling; Zhou, Wei; Li, Nianbing; Pan, Fusheng


    The following facile approach has been developed to prepare a biomimetic-structural superhydrophobic surface with high stabilities and strong resistances on 2024 Al alloy that are robust to harsh environments. First, a simple hydrothermal treatment in a La(NO3)3 aqueous solution was used to fabricate ginkgo-leaf like nanostructures, resulting in a superhydrophilic surface on 2024 Al. Then a low-surface-energy compound, dodecafluoroheptyl-propyl-trimethoxylsilane (Actyflon-G502), was used to modify the superhydrophilic 2024 Al, changing the surface character from superhydrophilicity to superhydrophobicity. The water contact angle (WCA) of such a superhydrophobic surface reaches up to 160°, demonstrating excellent superhydrophobicity. Moreover, the as-prepared superhydrophobic surface shows high stabilities in air-storage, chemical and thermal environments, and has strong resistances to UV irradiation, corrosion, and abrasion. The WCAs of such a surface almost remain unchanged (160°) after storage in air for 80 days, exposure in 250 °C atmosphere for 24 h, and being exposed under UV irradiation for 24 h, are more than 144° whether in acidic or alkali medium, and are more than 150° after 48 h corrosion and after abrasion under 0.98 kPa for 1000 mm length. The remarkable durability of the as-prepared superhydrophobic surface can be attributed to its stable structure and composition, which are due to the existence of lanthanum (hydr)oxides in surface layer. The robustness of the as-prepared superhydrophobic surface to harsh environments will open their much wider applications. The fabricating approach for such robust superhydrophobic surface can be easily extended to other metals and alloys.

  10. Surface Plasmon Coupling and Control Using Spherical Cap Structures

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Yu; Joly, Alan G.; Zhang, Xin; El-Khoury, Patrick Z.; Hess, Wayne P.


    Propagating surface plasmons (PSPs) launched from a protruded silver spherical cap structure are investigated using photoemission electron microscopy (PEEM) and finite difference time domain (FDTD) calculations. Our combined experimental and theoretical findings reveal that PSP coupling efficiency is comparable to conventional etched-in plasmonic coupling structures. Additionally, plasmon propagation direction can be varied by a linear rotation of the driving laser polarization. A simple geometric model is proposed in which the plasmon direction selectivity is proportional to the projection of the linear laser polarization on the surface normal. An application for the spherical cap coupler as a gate device is proposed. Overall, our results indicate that protruded cap structures hold great promise as elements in emerging surface plasmon applications.

  11. Structure and properties of GMA surfaced armour plates


    A. Klimpel; K. Luksa; Burda, M.


    Purpose: In the combat vehicles many materials can be used for the armour. Application of the monolithic armour plates in light combat vehicles is limited by the high armour weigh. Introduction of the layered armour plates is a way to limit the vehicle weight. In the paper test results of graded and nanostructural GMA surfaced armour plates are presented.Design/methodology/approach: Metallographic structure, chemical composition and hardness of surfaced layers were investigated in order to ex...

  12. Antireflective surface structures on optics for high energy lasers (United States)

    Busse, Lynda E.; Florea, Catalin M.; Shaw, L. Brandon; Frantz, Jesse; Bayya, Shyam; Poutous, Menelaos K.; Joshi, Rajendra; Aggarwal, Ishwar D.; Sanghera, Jas S.


    We report results for antireflective surface structures (ARSS) fabricated directly into the surface of optics and lenses which are important as high energy (multi-kW) laser components, including fused silica windows and lenses, YAG crystals and ceramics and spinel ceramics. Very low reflection losses as well as high laser damage thresholds have been measured for optics with ARSS. Progress to scale up the process for large size windows will also be presented..

  13. Structure determination of surface adsorption and surface alloy phases using medium energy ion scattering

    Energy Technology Data Exchange (ETDEWEB)

    Woodruff, D.P. E-mail:; Brown, D.; Quinn, P.D.; Noakes, T.C.Q.; Bailey, P


    Through a series of investigations of the quantitative structure of monolayer surface alloy phases of Cu(1 0 0)/Au, Cu(1 0 0)/Mn, Cu(1 1 1)/Sb and Ni(1 1 1)/Pb a number of aspects of the methodology of medium energy ion scattering (MEIS) have been investigated. These include the form of reliability-factors (R-factors) used to provide an objective test of the fit of experimental blocking curves and those simulated for different model structures, and the criteria used to define the precision and uniqueness of such models. The role of absolute calibration of the scattered ion yields and the appropriate choice of scattering geometry are also discussed in the context of these specific studies. The quantitative results for these surface alloy structures also cast some light on the effective atomic radii in such structures and highlight the general trend for phases with low surface corrugation or rumpling.

  14. Structural and surface changes of copper modified manganese oxides (United States)

    Gac, Wojciech; Słowik, Grzegorz; Zawadzki, Witold


    The structural and surface properties of manganese and copper-manganese oxides were investigated. The oxides were prepared by the redox-precipitation method. X-ray diffraction and electron microscopy studies evidenced transformation of cryptomelane-type nanoparticles with 1-D channel structure into the large MnO crystallites with regular rippled-like surface patterns under reduction conditions. The development of Cu/CuO nanorods from strongly dispersed species was evidenced. Coper-modified manganese oxides showed good catalytic performance in methanol steam reforming reaction for hydrogen production. Low selectivity to CO was observed in the wide range of temperatures.

  15. Structure of free surface crystallization of Hg: a first attempt

    Directory of Open Access Journals (Sweden)

    Bomont J.-M.


    Full Text Available Oscillatory density profiles (DP are a well-known feature occurring at the free surfaces of liquid metals. We analyse first the layered structure of Hg at or below the melting temperature with a simple interaction model [J.-M. Bomont and J.-L. Bretonnet, J. Chem. Phys. 124, 054504 (2006], by molecular dynamics simulation in slab geometry. Then, by investigating the in-plane structure, some state transitions are observed. In particular, crystalline planes, whose axes are tilted by several degrees from the surface normal, appear and seem to be signalized by flat DP.

  16. Surface plasmon polariton amplification in semiconductor-graphene-dielectric structure

    Energy Technology Data Exchange (ETDEWEB)

    Dadoenkova, Yuliya S. [Ulyanovsk State University, Ulyanovsk (Russian Federation); Novgorod State University, Veliky Novgorod (Russian Federation); Donetsk Institute for Physics and Technology, Donetsk (Ukraine); Moiseev, Sergey G. [Ulyanovsk State University, Ulyanovsk (Russian Federation); Kotelnikov Institute of Radio Engineering and Electronics, Russian Academy of Sciences, Ulyanovsk (Russian Federation); Abramov, Aleksei S. [Ulyanovsk State University, Ulyanovsk (Russian Federation); Kadochkin, Aleksei S.; Zolotovskii, Igor O. [Ulyanovsk State University, Ulyanovsk (Russian Federation); Institute of Nanotechnologies of Microelectronics of the Russian Academy of Sciences, 32A Leninskiy Prosp., 119991, Moscow (Russian Federation); Fotiadi, Andrei A. [Ulyanovsk State University, Ulyanovsk (Russian Federation); Universite de Mons (Belgium)


    A mechanism of amplification of surface plasmon polaritons due to the transfer of electromagnetic energy from a drift current wave into a far-infrared surface wave propagating along a semiconductor-dielectric boundary in waveguide geometry is proposed. A necessary condition of the interaction of these waves is phase matching condition, i. e., when the phase velocity of the surface wave approaches the drift velocity of charge carriers. It is shown that in the spectral region of the surface plasmon polariton slowing-down its amplification coefficient can reach values substantially exceeding the ohmic loss coefficient of the surface wave in the structure. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Surface forces between rough and topographically structured interfaces

    DEFF Research Database (Denmark)

    Thormann, Esben


    on the interaction between interfaces. This paper presents a review of the current state of understanding of the effect of surface roughness on DLVO forces, as well as on the interactions between topographically structured hydrophobic surfaces in water. While the first case is a natural choice because it represents......Within colloidal science, direct or indirect measurements of surface forces represent an important tool for developing a fundamental understanding of colloidal systems, as well as for predictions of the stability of colloidal suspensions. While the general understanding of colloidal interactions...... has developed significantly since the formulation of the DLVO theory, many problems still remain to be solved. One concrete problem is that the current theory has been developed for interaction between flat and chemically homogenous surfaces, which is in contrast to the surfaces of most natural...

  18. Waveguiding in surface plasmon polariton band gap structures

    DEFF Research Database (Denmark)

    Bozhevolnyi, S.I.; Østergaard, John Erland; Leosson, Kristjan


    Using near-held optical microscopy, we investigate propagation and scattering of surface plasmon polaritons (SPP's) excited in the wavelength range of 780-820 nm at nanostructured gold-film surfaces with areas of 200-nm-wide scatterers arranged in a 400-nm-period triangular lattice containing line...... defects. We observe the SPP reflection by such an area and SPP guiding along line defects at 782 nm, as well as significant deterioration of these effects is 815 nm, thereby directly demonstrating the SPP band gap effect and showing first examples of SPP channel waveguides in surface band gap structures....

  19. Ocular surface inflammation impairs structure and function of meibomian gland. (United States)

    Mizoguchi, Shin; Iwanishi, Hiroki; Arita, Reiko; Shirai, Kumi; Sumioka, Takayoshi; Kokado, Masahide; Jester, James V; Saika, Shizuya


    Dysfunction of the meibomian glands alters secreted meibum quantitatively and qualitatively that can lead to damage to the ocular surface epithelium. In response to an unstable tear film cause by meibomian gland dysfunction, ocular surface epithelium is damaged and expresses inflammatory cytokines leading to secondary ocular inflammation. In turn, inflammatory disorders of the palpebral conjunctiva and lid margin may affect the structure and function of meibomian gland. The disorders include allergic conjunctivitis, long-term usage of contact lenses, dermatological diseases that affect conjunctival homeostasis, Stevens-Johnson's syndrome or chemical burning of the ocular surface and lid margin. Copyright © 2017. Published by Elsevier Ltd.

  20. Thermodynamics and structure of liquid surfaces investigated directly with surface analytical tools

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Gunther [Flinders Univ., Adelaide, SA (Australia). Centre for NanoScale Science and Technology; Morgner, Harald [Leipzig Univ. (Germany). Wilhelm Ostwald Inst. for Physical and Theoretical Chemistry


    Measuring directly the composition, the distribution of constituents as function of the depth and the orientation of molecules at liquid surfaces is essential for determining physicochemical properties of liquid surfaces. While the experimental tools that have been developed for analyzing solid surfaces can in principal be applied to liquid surfaces, it turned out that they had to be adjusted to the particular challenges imposed by liquid samples, e.g. by the unavoidable vapor pressure and by the mobility of the constituting atoms/molecules. In the present work it is shown, how electron spectroscopy and ion scattering spectroscopy have been used for analyzing liquid surfaces. The emphasis of this review is on using the structural information gained for determining the physicochemical properties of liquid surfaces. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Radiocarbon dating reveals minimal collagen turnover in both healthy and osteoarthritic human cartilage

    DEFF Research Database (Denmark)

    Heinemeier, Katja M; Schjerling, Peter; Heinemeier, Jan


    The poor regenerative capacity of articular cartilage presents a major clinical challenge and may relate to a limited turnover of the cartilage collagen matrix. However, the collagen turnover rate during life is not clear, and it is debated whether osteoarthritis (OA) can influence it. Using......, no replacement of the collagen matrix happened after skeletal maturity and that neither OA nor tissue damage, per se, influenced collagen turnover. Regional differences in (14)C content across the joint surface showed that cartilage collagen located centrally on the joint surface is formed several years earlier...

  2. Studies on electronic structure of GaN(0001) surface

    CERN Document Server

    Xie Chang Kun; Xu Fa Qiang; Deng Rui; Liu Feng; Yibulaxin, K


    An electronic structure investigation on GaN(0001) is reported. The authors employ a full-potential linearized augmented plane-wave (FPLAPW) approach to calculate the partial density of state, which is in agreement with previous experimental results. The effects of the Ga3d semi-core levels on the electronic structure of GaN are discussed. The valence-electronic structure of the wurtzite GaN(0001) surface is investigated using synchrotron radiation excited angle-resolved photoemission spectroscopy. The bulk bands dispersion along GAMMA A direction in the Brillouin zones is measured using normal-emission spectra by changing photon-energy. The band structure derived from authors' experimental data is compared well with the results of authors' FPLAPW calculation. Furthermore, off-normal emission spectra are also measured along the GAMMA K and GAMMA M directions. Two surface states are identified, and their dispersions are characterized

  3. Structural and dynamical properties of water on chemically modified surfaces: The role of the instantaneous surface (United States)

    Bekele, Selemon; Tsige, Mesfin

    Surfaces of polymers such as atactic polystyrene (aPS) represent very good model systems for amorphous material surfaces. Such polymer surfaces are usually modified either chemically or physically for a wide range of applications that include friction, lubrication and adhesion. It is thus quite important to understand the structural and dynamical properties of liquids that come in contact with them to achieve the desired functional properties. Using molecular dynamics (MD) simulations, we investigate the structural and dynamical properties of water molecules in a slab of water in contact with atactic polystyrene surfaces of varying polarity. We find that the density of water molecules and the number distribution of hydrogen bonds as a function of distance relative to an instantaneous surface exhibit a structure indicative of a layering of water molecules near the water/PS interface. For the dynamics, we use time correlation functions of hydrogen bonds and the incoherent structure function for the water molecules. Our results indicate that the polarity of the surface dramatically affects the dynamics of the interfacial water molecules with the dynamics slowing down with increasing polarity. This work was supported by NSF Grant DMR1410290.

  4. In vivo measurement of localized tibiofemoral cartilage strains in response to dynamic activity. (United States)

    Sutter, E Grant; Widmyer, Margaret R; Utturkar, Gangadhar M; Spritzer, Charles E; Garrett, William E; DeFrate, Louis E


    Altered local mechanical loading may disrupt normal cartilage homeostasis and play a role in the progression of osteoarthritis. Currently, there are limited data quantifying local cartilage strains in response to dynamic activity in normal or injured knees. To directly measure local tibiofemoral cartilage strains in response to a dynamic hopping activity in normal healthy knees. We hypothesized that local regions of cartilage will exhibit significant compressive strains in response to hopping, while overall compartmental averages may not. Controlled laboratory study. Both knees of 8 healthy subjects underwent magnetic resonance imaging before and immediately after a dynamic hopping activity. Images were segmented and then used to create 3-dimensional surface models of bone and cartilage. These pre- and postactivity models were then registered using an iterative closest point technique to enable site-specific measurements of cartilage strain (defined as the normalized change in cartilage thickness before and after activity) on the femur and tibia. Significant strains were observed in both the medial and lateral tibial cartilage, with each compartment averaging a decrease of 5%. However, these strains varied with location within each compartment, reaching a maximum compressive strain of 8% on the medial plateau and 7% on the lateral plateau. No significant averaged compartmental strains were observed in the medial or lateral femoral cartilage. However, local regions of the medial and lateral femoral cartilage experienced significant compressive strains, reaching maximums of 6% and 3%, respectively. Local regions of both the femur and tibia experienced significant cartilage strains as a result of dynamic activity. An understanding of changes in cartilage strain distributions may help to elucidate the biomechanical factors contributing to cartilage degeneration after joint injury. Site-specific measurements of in vivo cartilage strains are important because altered

  5. Feedback-controlled laser-mediated cartilage reshaping. (United States)

    Wong, B J; Milner, T E; Harrington, A; Ro, J; Dao, X; Sobol, E N; Nelson, J S


    To demonstrate feedback-controlled laser-mediated cartilage reshaping using dynamic measurements of tissue optical properties and radiometric surface temperatures. Flat cartilage specimens were reshaped into curved configurations using a feedback-controlled laser device. Fresh porcine nasal septum, stripped of perichondrium and cut into uniform strips (25 x 10 x 1.5-2.1 mm) with a custom guillotine microtome. Cartilage specimens secured in a cylindrical reshaping jig (2.5 cm in diameter) and irradiated with an Nd:YAG laser (lambda = 1.32 microns, 25 W/cm2, 50-Hz pulse repetition rate). During laser irradiation, radiometric surface temperature was measured along with changes in forward-scattered light from a diode probe laser (lambda = 650 nm, 5 mW), using a lock-in detection technique. Sequential irradiation of the specimen outer surface was made (3 laser passes). Characteristic changes in tissue temperature and light-scattering signals were used to terminate laser irradiation. Effective reshaping was accomplished for both thin (1.5-mm) and thick (2.1-mm) specimens. Following reshaping, specimens were stored in saline solution at 4 degrees C for 21 days. No return to the original flat configuration was noted during this period. The prototype device effectively reshapes flat native porcine cartilage into curve configurations. The use of optical and thermal signals provides effective feedback control for optimizing the reshaping process.

  6. The determination of turbulent structures in the atmospheric surface layer

    NARCIS (Netherlands)

    Schols, J.L.J.


    The turbulent flow in the atmospheric surface layer (ASL) contains turbulent structures, which are defined as spatially coherent, organized flow motions. 'Organized' means that characteristic patterns, observed at a point in space, occur almost simultaneously in more than one turbulence signal and

  7. Visual evaluation of beef tenderness by using surface structural ...

    African Journals Online (AJOL)

    The steaks were evaluated by visual analysis for colour, marbling, fibre separation, surface texture and structure integrity by a 10-member trained panel. Colour was also measured by the CIE L*, a*, b* system using a Minolta meter, and tenderness was measured by means of Warner-Bratzler shear force. High negative ...

  8. Probing surface structures of Shewanella spp. by microelectrophoresis

    NARCIS (Netherlands)

    Dague, E.; Duval, J.F.L.; Jorand, R.; Thomas, F.; Gaboriaud, F.


    Long-range electrostatic forces substantially influence bacterial interactions and bacterial adhesion during the preliminary steps of biofilm formation. The strength of these forces depends strongly on the structure of the bacterium surfaces investigated. The latter may be addressed from appropriate

  9. Fracture Resistance, Surface Defects and Structural Strength of Glass

    NARCIS (Netherlands)

    Rodichev, Y.M.; Veer, F.A.


    This paper poses the theory that the fracture resistance of basic float glass is dependent on it physicochemical properties and the surface defects fonned under the float glass production, glass processing and handling at the service conditions compose the aggregate basis for structural glass

  10. Synthesis, structure and Hirshfeld surface analysis, vibrational and ...

    Indian Academy of Sciences (India)

    The water molecule is placed between the layers formed by organic cations along the b axis. Net- work hydrogen-bonding and π–π interactions lead to the formation of a three-dimensional architecture. Hirshfeld surface analysis for visually analysing intermolecular interactions in crystal structures employing molecular sur-.

  11. Visual evaluation of beef tenderness by using surface structural ...

    African Journals Online (AJOL)

    Kedibone KY. Modika


    Aug 1, 2015 ... The steaks were evaluated by visual analysis for colour, marbling, fibre separation, surface texture and structure integrity by a 10-member trained panel. Colour was also measured by the CIE L*, a*, b* system using a Minolta meter, and tenderness was measured by means of Warner-Bratzler shear force.

  12. Structural analysis and surface morphology of quartz | Jamo ...

    African Journals Online (AJOL)

    -ray diffraction (XRD) and scanning electron microscopy (SEM) were used to observe the surface and internal structure of the quartz. The results among other things revealed that the quartz consist of mainly silica (SiO2), with crystalline ...

  13. Metabolism of Cartilage Proteoglycans in Health and Disease (United States)

    Vynios, Demitrios H.


    Cartilage proteoglycans are extracellular macromolecules with complex structure, composed of a core protein onto which a variable number of glycosaminoglycan chains are attached. Their biosynthesis at the glycosaminoglycan level involves a great number of sugar transferases well-orchestrated in Golgi apparatus. Similarly, their degradation, either extracellular or intracellular in lysosomes, involves a large number of hydrolases. A deficiency or malfunction of any of the enzymes participating in cartilage proteoglycan metabolism may lead to severe disease state. This review summarizes the findings regarding this topic. PMID:25105124

  14. Metabolism of Cartilage Proteoglycans in Health and Disease

    Directory of Open Access Journals (Sweden)

    Demitrios H. Vynios


    Full Text Available Cartilage proteoglycans are extracellular macromolecules with complex structure, composed of a core protein onto which a variable number of glycosaminoglycan chains are attached. Their biosynthesis at the glycosaminoglycan level involves a great number of sugar transferases well-orchestrated in Golgi apparatus. Similarly, their degradation, either extracellular or intracellular in lysosomes, involves a large number of hydrolases. A deficiency or malfunction of any of the enzymes participating in cartilage proteoglycan metabolism may lead to severe disease state. This review summarizes the findings regarding this topic.

  15. Bio-Inspired Functional Surfaces Based on Laser-Induced Periodic Surface Structures

    Directory of Open Access Journals (Sweden)

    Frank A. Müller


    Full Text Available Nature developed numerous solutions to solve various technical problems related to material surfaces by combining the physico-chemical properties of a material with periodically aligned micro/nanostructures in a sophisticated manner. The utilization of ultra-short pulsed lasers allows mimicking numerous of these features by generating laser-induced periodic surface structures (LIPSS. In this review paper, we describe the physical background of LIPSS generation as well as the physical principles of surface related phenomena like wettability, reflectivity, and friction. Then we introduce several biological examples including e.g., lotus leafs, springtails, dessert beetles, moth eyes, butterfly wings, weevils, sharks, pangolins, and snakes to illustrate how nature solves technical problems, and we give a comprehensive overview of recent achievements related to the utilization of LIPSS to generate superhydrophobic, anti-reflective, colored, and drag resistant surfaces. Finally, we conclude with some future developments and perspectives related to forthcoming applications of LIPSS-based surfaces.

  16. Transcriptomic profiling of cartilage ageing

    Directory of Open Access Journals (Sweden)

    Mandy Jayne Peffers


    Full Text Available The musculoskeletal system is severely affected by the ageing process, with many tissues undergoing changes that lead to loss of function and frailty. Articular cartilage is susceptible to age related diseases, such as osteoarthritis. Applying RNA-Seq to young and old equine cartilage, we identified an over-representation of genes with reduced expression relating to extracellular matrix, degradative proteases, matrix synthetic enzymes, cytokines and growth factors in cartilage from older donors. Here we describe the contents and quality controls in detail for the gene expression and related results published by Peffers and colleagues in Arthritis Research and Therapy 2013 associated with the data uploaded to ArrayExpress (E-MTAB-1386.

  17. Local structural ordering in surface-confined liquid crystals (United States)

    Śliwa, I.; Jeżewski, W.; Zakharov, A. V.


    The effect of the interplay between attractive nonlocal surface interactions and attractive pair long-range intermolecular couplings on molecular structures of liquid crystals confined in thin cells with flat solid surfaces has been studied. Extending the McMillan mean field theory to include finite systems, it has been shown that confining surfaces can induce complex orientational and translational ordering of molecules. Typically, local smectic A, nematic, and isotropic phases have been shown to coexist in certain temperature ranges, provided that confining cells are sufficiently thick, albeit finite. Due to the nonlocality of surface interactions, the spatial arrangement of these local phases can display, in general, an unexpected complexity along the surface normal direction. In particular, molecules located in the vicinity of surfaces can still be organized in smectic layers, even though nematic and/or isotropic order can simultaneously appear in the interior of cells. The resulting surface freezing of smectic layers has been confirmed to occur even for rather weak surface interactions. The surface interactions cannot, however, prevent smectic layers from melting relatively close to system boundaries, even when molecules are still arranged in layers within the central region of the system. The internal interfaces, separating individual liquid-crystal phases, are demonstrated here to form fronts of local finite-size transitions that move across cells under temperature changes. Although the complex molecular ordering in surface confined liquid-crystal systems can essentially be controlled by temperature variations, specific thermal properties of these systems, especially the nature of the local transitions, are argued to be strongly conditioned to the degree of molecular packing.

  18. Advances in Application of Mechanical Stimuli in Bioreactors for Cartilage Tissue Engineering. (United States)

    Li, Ke; Zhang, Chunqiu; Qiu, Lulu; Gao, Lilan; Zhang, Xizheng


    often ignore the importance of biochemical factors to the growth and development of engineered cartilage. In our point of view, only by fully considering synergistic effects of mechanical and biochemical factors can we find appropriate culture conditions for functional cartilage constructs. Once again, rolling-sliding-compression load under appropriate biochemical conditions may be conductive to realize the adaptive development between the structure and function of engineered cartilage in vitro.

  19. Microwave treatment of xenogeneic cartilage transplants

    NARCIS (Netherlands)

    Visser, C. E.; Boon, M. E.; Visser, P. E.; Kok, L. P.


    Human rib cartilage was irradiated with microwaves according to six different methods and transplanted into rabbits. Untreated rib cartilage preserved in Cialit served as a control. After 12 and 40 wk of implantation, the microscopic appearance of these xenogeneic cartilage transplants was given a

  20. Plant Surfaces: Structures and Functions for Biomimetic Innovations (United States)

    Barthlott, Wilhelm; Mail, Matthias; Bhushan, Bharat; Koch, Kerstin


    An overview of plant surface structures and their evolution is presented. It combines surface chemistry and architecture with their functions and refers to possible biomimetic applications. Within some 3.5 billion years biological species evolved highly complex multifunctional surfaces for interacting with their environments: some 10 million living prototypes (i.e., estimated number of existing plants and animals) for engineers. The complexity of the hierarchical structures and their functionality in biological organisms surpasses all abiotic natural surfaces: even superhydrophobicity is restricted in nature to living organisms and was probably a key evolutionary step with the invasion of terrestrial habitats some 350-450 million years ago in plants and insects. Special attention should be paid to the fact that global environmental change implies a dramatic loss of species and with it the biological role models. Plants, the dominating group of organisms on our planet, are sessile organisms with large multifunctional surfaces and thus exhibit particular intriguing features. Superhydrophilicity and superhydrophobicity are focal points in this work. We estimate that superhydrophobic plant leaves (e.g., grasses) comprise in total an area of around 250 million km2, which is about 50% of the total surface of our planet. A survey of structures and functions based on own examinations of almost 20,000 species is provided, for further references we refer to Barthlott et al. (Philos. Trans. R. Soc. A 374: 20160191, 1). A basic difference exists between aquatic non-vascular and land-living vascular plants; the latter exhibit a particular intriguing surface chemistry and architecture. The diversity of features is described in detail according to their hierarchical structural order. The first underlying and essential feature is the polymer cuticle superimposed by epicuticular wax and the curvature of single cells up to complex multicellular structures. A descriptive terminology

  1. Novel Genetic Variants for Cartilage Thickness and Hip Osteoarthritis

    NARCIS (Netherlands)

    M.C. Castaño Betancourt (Martha); D.S. Evans (Daniel); Y.F.M. Ramos (Yolande); Boer, C.G. (Cindy G.); S. Metrustry (Sarah); Liu, Y. (Youfang); W. den Hollander (Wouter); J. Van Rooij (Jeroen); Kraus, V.B. (Virginia B.); Yau, M.S. (Michelle S.); B.D. Mitchell (Braxton); Muir, K. (Kenneth); A. Hofman (Albert); M. Doherty (Michael); S. Doherty (Sally); W. Zhang (Weiya); R. Kraaij (Robert); F. Rivadeneira Ramirez (Fernando); Barrett-Connor, E. (Elizabeth); R.A. MacIewicz (Rose); N.K. Arden (Nigel); R.G.H.H. Nelissen (Rob); M. Kloppenburg (Margreet); Jordan, J.M. (Joanne M.); M.C. Nevitt (Michael); E. Slagboom (Eline); D. Hart (Deborah); F.P.J.G. Lafeber (Floris); U. Styrkarsdottir (Unnur); E. Zeggini (Eleftheria); E. Evangelou (Evangelos); T.D. Spector (Timothy); A.G. Uitterlinden (André); N.E. Lane; I. Meulenbelt (Ingrid); A.M. Valdes (Ana Maria); J.B.J. van Meurs (Joyce)


    textabstractOsteoarthritis is one of the most frequent and disabling diseases of the elderly. Only few genetic variants have been identified for osteoarthritis, which is partly due to large phenotype heterogeneity. To reduce heterogeneity, we here examined cartilage thickness, one of the structural

  2. Structural coloration of metallic surfaces with micro/nano-structures induced by elliptical vibration texturing (United States)

    Yang, Yang; Pan, Yayue; Guo, Ping


    Creating orderly periodic micro/nano-structures on metallic surfaces, or structural coloration, for control of surface apparent color and optical reflectivity has been an exciting research topic over the years. The direct applications of structural coloration include color marking, display devices, and invisibility cloak. This paper presents an efficient method to colorize metallic surfaces with periodic micro/nano-gratings using elliptical vibration texturing. When the tool vibration is coupled with a constant cutting velocity, controlled periodic ripples can be generated due to the overlapping tool trajectory. These periodic ripples with a wavelength near visible spectrum can act as micro-gratings to introduce iridescent colors. The proposed technique also provides a flexible method for color marking of metallic surfaces with arbitrary patterns and images by precise control of the spacing distance and orientation of induced micro/nano-ripples. Theoretical analysis and experimental results are given to demonstrate structural coloration of metals by a direct mechanical machining technique.

  3. Novel genetic algorithm search procedure for LEED surface structure determination. (United States)

    Viana, M L; dos Reis, D D; Soares, E A; Van Hove, M A; Moritz, W; de Carvalho, V E


    Low Energy Electron Diffraction (LEED) is one of the most powerful experimental techniques for surface structure analysis but until now only a trial-and-error approach has been successful. So far, fitting procedures developed to optimize structural and nonstructural parameters-by minimization of the R-factor-have had a fairly small convergence radius, suitable only for local optimization. However, the identification of the global minimum among the several local minima is essential for complex surface structures. Global optimization methods have been applied to LEED structure determination, but they still require starting from structures that are relatively close to the correct one, in order to find the final structure. For complex systems, the number of trial structures and the resulting computation time increase so rapidly that the task of finding the correct model becomes impractical using the present methodologies. In this work we propose a new search method, based on Genetic Algorithms, which is able to determine the correct structural model starting from completely random structures. This method-called here NGA-LEED for Novel Genetic Algorithm for LEED-utilizes bond lengths and symmetry criteria to select reasonable trial structures before performing LEED calculations. This allows a reduction of the parameter space and, consequently of the calculation time, by several orders of magnitude. A refinement of the parameters by least squares fit of simulated annealing is performed only at some intermediate stages and in the final step. The method was successfully tested for two systems, Ag(1 1 1)(4 × 4)-O and Au(1 1 0)-(1 × 2), both in theory versus theory and in theory versus experiment comparisons. Details of the implementation as well as the results for these two systems are presented.

  4. Research progress of the types and preparation techniques of scaffold materials in cartilage tissue engineering (United States)

    Fu, Na; Dong, Tengzhe; Meng, Ai; Meng, Zhaosong; Zhu, Bofeng; Lin, Yunfeng


    The management of chondral defects has been a challenge for a long time because of the poor self-healing capacity of articular cartilage. Many approaches ranging from symptomatic treatment to structural cartilage regeneration are not that successful with very limited satisfactory results. Chondral defects caused by tumor, trauma, infection, congenital malformations are very common in clinical trials. It seriously affects the patient's physical function and quality of life. Cartilage tissue engineering, which involves novel natural scaffolds, has emerged as a promising strategy for cartilage regeneration and repair. In this review, we are aimed at reviewing the application of scaffolds in cartilage tissue engineering,including the conditions required to meet the desired scaffold, the preparation of scaffold materials, preparation methods and so on. Copyright© Bentham Science Publishers; For any queries, please email at

  5. Surface and Structure: Transcribing Intonation within and across Languages

    Directory of Open Access Journals (Sweden)

    Sónia Frota


    Full Text Available Intonation is the phonologically structured variation in phonetic features, primarily pitch, to express phrase-level meanings. As in other speech sound domains, analyzing intonation involves mapping continuously variable physical parameters to categories. The categories of intonation are organized in a set of relations and rule-governed distributions that define the intonation system of a language. From physical realizations, as shown by pitch tracks, surface or phonetic tonal patterns can be identified in terms of tonal targets. Whether surface patterns correspond or not to categories within a given intonation system requires looking at their distributions and contrastiveness. In this paper, I assume the view that a transcription is an analysis of the intonation system, which ultimately aims to identify the contrastive intonation categories of a given language and establish how they signal meaning. Under this view, it is crucial to discuss the ways surface pitch patterns and structural pitch patterns (or phonological categories are related. Given that intonational analysis is driven by system-internal considerations and that cues to a given category can vary across languages, it is also important to address the issue of how a language-specific transcription can be reconciled with the need and ability to do cross-language comparison of intonation. Bearing on these two issues, I discuss surface and structure in intonational analysis, drawing on mismatches between (dissimilarities in the phonetics and phonology of pitch contours, across languages and language varieties.

  6. Valgus Stress Radiographs Predict Lateral-Compartment Cartilage Thickness but Not Cartilage Degeneration in Varus Osteoarthritis. (United States)

    Waldstein, Wenzel; Schmidt-Braekling, Tom; Perino, Giorgio; Kasparek, Maximilian F; Windhager, Reinhard; Boettner, Friedrich


    Intact cartilage in the lateral compartment is an important requirement for medial unicompartmental knee arthroplasty. This study sought to determine how measurements of joint space width in the lateral compartment on valgus stress radiographs compare to cartilage thickness as measured with a precise needle test, and whether cartilage thickness is a predictor of cartilage degeneration. A consecutive series of 100 knees undergoing total knee arthroplasty for end-stage varus osteoarthritis was studied. Twenty-eight knees were retrospectively excluded because not all data were available, leaving 72 knees (61 patients; mean age, 67 years [49-87]). On calibrated valgus stress radiographs, lateral-compartment joint space width was measured. During surgery, osteochondral samples of the distal lateral femur and the lateral tibia plateau were harvested. Cartilage thickness and histology were assessed. Cartilage thickness of tibia and femur was defined as lateral-compartment cartilage thickness. Lateral-compartment joint space width on valgus stress radiographs and lateral-compartment cartilage thickness correlated well (rs = 0.671, P cartilage histology according to the osteoarthritis cartilage histopathology assessment system, and cartilage thickness on the lateral tibia plateau (rs = -0.060, P = .614) and cartilage thickness on the distal lateral femur (rs = -0.128, P = .282) was observed. Valgus stress radiographs can assess combined cartilage thickness in the lateral compartment of the knee. Cartilage thickness, however, is a poor predictor of cartilage degeneration. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Can atom-surface potential measurements test atomic structure models? (United States)

    Lonij, Vincent P A; Klauss, Catherine E; Holmgren, William F; Cronin, Alexander D


    van der Waals (vdW) atom-surface potentials can be excellent benchmarks for atomic structure calculations. This is especially true if measurements are made with two different types of atoms interacting with the same surface sample. Here we show theoretically how ratios of vdW potential strengths (e.g., C₃(K)/C₃(Na)) depend sensitively on the properties of each atom, yet these ratios are relatively insensitive to properties of the surface. We discuss how C₃ ratios depend on atomic core electrons by using a two-oscillator model to represent the contribution from atomic valence electrons and core electrons separately. We explain why certain pairs of atoms are preferable to study for future experimental tests of atomic structure calculations. A well chosen pair of atoms (e.g., K and Na) will have a C₃ ratio that is insensitive to the permittivity of the surface, whereas a poorly chosen pair (e.g., K and He) will have a ratio of C₃ values that depends more strongly on the permittivity of the surface.

  8. Cell Therapy and Tissue Engineering Approaches for Cartilage Repair and/or Regeneration (United States)

    Mardones, Rodrigo; Jofré, Claudio M.; Minguell, José J.


    Articular cartilage injuries caused by traumatic, mechanical and/or by progressive degeneration result in pain, swelling, subsequent loss of joint function and finally osteoarthritis. Due to the peculiar structure of the tissue (no blood supply), chondrocytes, the unique cellular phenotype in cartilage, receive their nutrition through diffusion from the synovial fluid and this limits their intrinsic capacity for healing. The first cellular avenue explored for cartilage repair involved the in situ transplantation of isolated chondrocytes. Latterly, an improved alternative for the above reparative strategy involved the infusion of mesenchymal stem cells (MSC), which in addition to a self-renewal capacity exhibit a differentiation potential to chondrocytes, as well as a capability to produce a vast array of growth factors, cytokines and extracellular matrix compounds involved in cartilage development. In addition to the above and foremost reparative options up till now in use, other therapeutic options have been developed, comprising the design of biomaterial substrates (scaffolds) capable of sustaining MSC attachment, proliferation and differentiation. The implantation of these engineered platforms, closely to the site of cartilage damage, may well facilitate the initiation of an ‘in situ’ cartilage reparation process. In this mini-review, we examined the timely and conceptual development of several cell-based methods, designed to repair/regenerate a damaged cartilage. In addition to the above described cartilage reparative options, other therapeutic alternatives still in progress are portrayed. PMID:26019754

  9. Biomimetic surface structuring using cylindrical vector femtosecond laser beams (United States)

    Skoulas, Evangelos; Manousaki, Alexandra; Fotakis, Costas; Stratakis, Emmanuel


    We report on a new, single-step and scalable method to fabricate highly ordered, multi-directional and complex surface structures that mimic the unique morphological features of certain species found in nature. Biomimetic surface structuring was realized by exploiting the unique and versatile angular profile and the electric field symmetry of cylindrical vector (CV) femtosecond (fs) laser beams. It is shown that, highly controllable, periodic structures exhibiting sizes at nano-, micro- and dual- micro/nano scales can be directly written on Ni upon line and large area scanning with radial and azimuthal polarization beams. Depending on the irradiation conditions, new complex multi-directional nanostructures, inspired by the Shark’s skin morphology, as well as superhydrophobic dual-scale structures mimicking the Lotus’ leaf water repellent properties can be attained. It is concluded that the versatility and features variations of structures formed is by far superior to those obtained via laser processing with linearly polarized beams. More important, by exploiting the capabilities offered by fs CV fields, the present technique can be further extended to fabricate even more complex and unconventional structures. We believe that our approach provides a new concept in laser materials processing, which can be further exploited for expanding the breadth and novelty of applications.

  10. Distraction osteogenesis combined with tissue-engineered cartilage in the reconstruction of condylar osteochondral defect. (United States)

    Yu, Hongbo; Yang, Xin; Cheng, Jie; Wang, Xudong; Shen, Steve Guofang


    Surgical rehabilitation of condylar osteochondral defect remains a challenge for surgeons. The aim of this study was to explore the feasibility of combining distraction osteogenesis with tissue-engineered cartilage in the reconstruction of condylar osteochondral defect. A condylar defect model was established in 18 goats that were randomly divided into 2 groups: the experimental group and the control group. Mandibular ramus osteotomies were performed and distractors were implanted in all animals. The mixture of chondrocytes and Pluronic F-127 (Sigma-Aldrich, St Louis, MO) was injected on the notched surface of a transport disc in the experimental group, whereas a scaffold without cells was transplanted into the control group. After a 5-day latency period, distraction was activated at a rate of 0.5 mm twice per day for 15 days. The goats were killed at the end of the fourth, eighth, or twelfth week in the consolidation period. Specimens were harvested and macroscopic evaluation, as well as Masson trichrome and immunohistochemical staining, were performed to compare the results between the 2 groups. Osteogenesis was found in all animals with no evidence of infection. Condyle-like structures were formed at the upper end of the transport segment in all animals. The neocondylar surface was covered with a layer of smooth lustrous fibrocartilage in the experimental group. Collagen was shown in the reparative tissue by Masson trichrome staining. Immunohistochemistry staining indicated that type II collagen was positive, whereas type I collagen was negative on the neocondylar surface in the experimental group. No cartilage-like tissue was seen, but fibrous tissue was identified at the bony surface in the control group. In the experimental group, immunofluorescent semiquantitative analysis showed that the positive rate of type II collagen was 1.62% ± 0.53% after the fourth week of consolidation, and it increased to 12.39% ± 3.27% after the twelfth week. There was a

  11. Endothelial plasmalemmal vesicles have a characteristic striped bipolar surface structure. (United States)

    Peters, K R; Carley, W W; Palade, G E


    Capillary endothelial cells have a large population of small (65-80 nm diameter in transmission electron microscopy) vesicles of which a large fraction is associated with the plasmalemma of the luminal and abluminal side. We studied the fine structure and distribution of these plasmalemmal vesicles by high resolution scanning electron microscopy in cultured endothelial cells obtained from bovine adrenal cortical capillaries. Cell monolayers were covered with polylysine-coated silicon chips, split in high potassium buffer, fixed in aldehyde mixtures, and then treated with OsO4 and thiocarbohydrazide. After critical point drying, the specimens were coated with a thin (less than 2 nm) continuous film of chromium. On the cytoplasmic aspect of the dorsal plasmalemmal fragments seen in such specimens, plasmalemmal vesicles appear as uniform vesicular protrusions approximately 70-90 nm in diameter, preferentially concentrated in distinct large fields in which they occur primarily as single units. Individual plasmalemmal vesicles exhibit a striped surface fine structure which consists of ridges approximately 10 nm in diameter, separated by furrows and oriented as meridians, often ending at two poles on opposite sides of the vesicles in a plane parallel to the plasmalemma. This striped surface structure is clearly distinct from the cage structure of coated pits found, at low surface density, on the same specimens. The cytoplasmic aspect of the plasmalemma proper is covered by a fibrillar infrastructure which does not extend over plasmalemmal vesicles but on which the latter appear to be anchored by fine filaments.

  12. Enhanced perfume surface delivery to interfaces using surfactant surface multilayer structures. (United States)

    Bradbury, Robert; Penfold, Jeffrey; Thomas, Robert K; Tucker, Ian M; Petkov, Jordan T; Jones, Craig


    Enhanced surface delivery and retention of perfumes at interfaces are the keys to their more effective and efficient deployment in a wide range of home and personal care related formulations. It has been previously demonstrated that the addition of multivalent counterions, notably Ca(2+), induces multilayer adsorption at the air-water interface for the anionic surfactant, sodium dodecyl-6-benzenesulfonate, LAS-6. Neutron reflectivity, NR, measurements are reported here which demonstrate that such surfactant surface multilayer structures are a potentially promising vehicle for enhanced delivery of perfumes to interfaces. The data show that the incorporation of the model perfumes, phenylethanol, PE, and linalool, LL, into the surface multilayer structure formed by LAS-6/Ca(2+) results in the surface structures being retained up to relatively high perfume mole fractions. Furthermore the amount of perfume at the surface is enhanced by at least an order of magnitude, compared to that co-adsorbed with a surfactant monolayer. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. The bio in the ink : cartilage regeneration with bioprintable hydrogels and articular cartilage-derived progenitor cells

    NARCIS (Netherlands)

    Levato, Riccardo; Webb, William R; Otto, Iris A; Mensinga, Anneloes; Zhang, Yadan; van Rijen, Mattie|info:eu-repo/dai/nl/304817856; van Weeren, P. René; Khan, Ilyas M.; Malda, Jos


    Cell-laden hydrogels are the primary building blocks for bioprinting, and, also termed bioinks, are the foundations for creating structures that can potentially recapitulate the architecture of articular cartilage. To be functional, hydrogel constructs need to unlock the regenerative capacity of

  14. Electrostatic cloaking of surface structure for dynamic wetting (United States)

    Shiomi, Junichiro; Nita, Satoshi; Do-Quang, Minh; Wang, Jiayu; Chen, Yu-Chung; Suzuki, Yuji; Amberg, Gustav


    Dynamic wetting problems are fundamental to the understanding of the interaction between liquids and solids. Even in a superficially simple experimental situation, such as a droplet spreading over a dry surface, the result may depend not only on the liquid properties but also strongly on the substrate-surface properties; even for macroscopically smooth surfaces, the microscopic geometrical roughness can be important. In addition, as surfaces may often be naturally charged, or electric fields are used to manipulate fluids, electric effects are crucial components that influence wetting phenomena. Here we investigate the interplay between electric forces and surface structures in dynamic wetting. While surface microstructures can significantly hinder the spreading, we find that the electrostatics can ``cloak'' the microstructures, i.e. deactivate the hindering. We identify the physics in terms of reduction in contact-line friction, which makes the dynamic wetting inertial force dominant and insensitive to the substrate properties. This work was financially supported in part by, the Japan Society for the Promotion of Science, Swedish Governmental Agency for Innovation Systems, and the Japan Science and Technology Agency.

  15. Enhanced water repellency of surfaces coated with multiscale carbon structures (United States)

    Marchalot, Julien; Ramos, Stella. M. M.; Pirat, Christophe; Journet, Catherine


    Low cost and well characterized superhydrophobic surfaces are frequently required for industrial applications. Materials are commonly structured at the micro or nano scale. Surfaces decorated with nanotube derivatives synthesized by plasma enhanced chemical vapor deposition (PECVD) are of particular interest, since suitable modifications in the growth parameters can lead to numerous designs. In this article, we present surfaces that are selected for their specific wetting features with patterns ranging from dense forests to jungles with concave (re-entrant) surface such as flake-like multiscale roughness. Once these surfaces are functionalized adequately, their wetting properties are investigated. Their ability to sustain a superhydrophobic state for sessile water drops is examined. Finally, we propose a design to achieve a robust so-called ;Fakir; state, even for micrometer-sized drops, whereas with classic nanotubes forests it is not achievable. Thus, the drop remains on the apex of the protrusions with a high contact angle and a low contact angle hysteresis, while the surface features demonstrate good mechanical resistance against capillary forces.

  16. The increased swelling and instantaneous deformation of osteoarthritic cartilage is highly correlated with collagen degradation. (United States)

    Bank, R A; Soudry, M; Maroudas, A; Mizrahi, J; TeKoppele, J M


    To provide evidence for the hypothesis that the loss of tensile strength of osteoarthritic (OA) cartilage (resulting in swelling-the hallmark of OA) is due to an impaired collagen network and not to loss or degradation of proteoglycans. The amount of degraded collagen molecules, the fixed charge density (FCD) on a dry-weight basis, the degree of swelling in saline, and the instantaneous deformation (ID; a test reflecting the tensile stiffness of the collagen network) were measured in full-depth OA femoral condyle samples. In addition, levels of the crosslink hydroxylysylpyridinoline (HP), the amount of degraded collagen molecules, and the degree of swelling were determined in the 3 zones (surface, middle, and deep) of OA cartilage. We also compared the ID of normal and OA cartilage. In full-depth OA cartilage, a close relationship was found between swelling and ID. Swelling and ID correlated strongly with the amount of degraded collagen molecules, and were not related to FCD. OA cartilage showed the same zonal pattern in HP levels as normal cartilage (i.e., an increase with depth). No relationship was found between collagen crosslinking and swelling of the surface, middle, and deep zones. In all 3 zones, swelling was proportional to the amount of degraded collagen molecules. Compared with that of normal cartilage, the change in ID of OA cartilage was most pronounced at the surface in a direction parallel to the direction of the collagen fibrils. The decreased stiffness of the OA collagen network (as measured by swelling and ID) is strongly related to the amount of degraded collagen molecules. The anisotropy in ID parallel and perpendicular to the direction of the fibrils revealed that the impairment of strength resides mainly in, and not between, the fibrils. Proteoglycans play only a minor role in the degeneration of the tensile stiffness of OA cartilage.

  17. T1rho mapping of entire femoral cartilage using depth- and angle-dependent analysis

    Energy Technology Data Exchange (ETDEWEB)

    Nozaki, Taiki; Kaneko, Yasuhito; Yu, Hon J.; Yoshioka, Hiroshi [University of California Irvine, Department of Radiological Sciences, Orange, CA (United States); Kaneshiro, Kayleigh [University of California Irvine, School of Medicine, Irvine, CA (United States); Schwarzkopf, Ran [University of California Irvine, Department of Orthopedic Surgery, Irvine, CA (United States); Hara, Takeshi [Gifu University Graduate School of Medicine, Department of Intelligent Image Information, Division of Regeneration and Advanced Medical Sciences, Gifu (Japan)


    To create and evaluate normalized T1rho profiles of the entire femoral cartilage in healthy subjects with three-dimensional (3D) angle- and depth-dependent analysis. T1rho images of the knee from 20 healthy volunteers were acquired on a 3.0-T unit. Cartilage segmentation of the entire femur was performed slice-by-slice by a board-certified radiologist. The T1rho depth/angle-dependent profile was investigated by partitioning cartilage into superficial and deep layers, and angular segmentation in increments of 4 over the length of segmented cartilage. Average T1rho values were calculated with normalized T1rho profiles. Surface maps and 3D graphs were created. T1rho profiles have regional and depth variations, with no significant magic angle effect. Average T1rho values in the superficial layer of the femoral cartilage were higher than those in the deep layer in most locations (p < 0.05). T1rho values in the deep layer of the weight-bearing portions of the medial and lateral condyles were lower than those of the corresponding non-weight-bearing portions (p < 0.05). Surface maps and 3D graphs demonstrated that cartilage T1rho values were not homogeneous over the entire femur. Normalized T1rho profiles from the entire femoral cartilage will be useful for diagnosing local or early T1rho abnormalities and osteoarthritis in clinical applications. (orig.)

  18. Characteristics of turbulent structures in the unstable atmospheric surface layer (United States)

    Schols, J. L. J.; Jansen, A. E.; Krom, J. G.


    An atmospheric surface-layer (ASL) experiment conducted at a meteorological site in the Oostelijk-Flevoland polder of the Netherlands is described. Turbulent fluctuations of wind velocity, air temperature and static pressure were measured, using three 10 m towers. Simultaneous turbulent signals at several heights on the towers were used to investigate the properties of the turbulent structures which contribute most significantly to the turbulent vertical transports in the unstable ASL. These turbulent structures produce between 30 and 50% of the mean turbulent vertical transport of horizontal alongwind momentum and they contribute to between 40 and 50% of the mean turbulent vertical heat transport; in both cases this occurs during 15 to 20% of the total observation time. The translation speed of the turbulent structures equals the wind speed averaged over the depth of the ASL, which scales on the surface friction velocity. The inclination angle of the temperature interface at the upstream edge of the turbulent structures to the surface is significantly smaller than that of the internal shear layer, which is associated with the temperature interface. The turbulent structures in the unstable ASL are determined by a large-scale temperature field: Convective motions, which encompass the whole depth of the planetary boundary layer (PBL), penetrate into the ASL. The curvature of the vertical profile of mean horizontal alongwind velocity forces the alignment of the convective cells in the flow direction (Kuettner, 1971), which have an average length of several hundreds of metres and an average width of a few tens of metres. This mechanism leads to the formation of turbulent structures, which extend throughout the depth of the ASL.

  19. Effect of articular cartilage proteoglycan depletion on high frequency ultrasound backscatter. (United States)

    Pellaumail, B; Watrin, A; Loeuille, D; Netter, P; Berger, G; Laugier, P; Saïed, A


    To study the effect of variations of articular cartilage proteoglycans (PG) on high-frequency ultrasound backscatter. The study was performed on patellar cartilages of immature and mature rats (N=36). The variation of PG content was induced by enzyme digestion. Control and treated cartilages were explored in vitro using a 55MHz scanning acoustic microscopy, then assessed by histology for the fibrillar collagen organization analysis. The variations of proteoglycan and collagen content were evaluated. Thickness measurements performed on both B-scan images and histologic sections were compared. Ultrasonic radio-frequency signals reflected by the cartilage surface and backscattered from its internal matrix were processed to estimate the integrated reflection coefficient (IRC) and apparent integrated backscatter (AIB). Although hyaluronidase treatment of immature and mature cartilages removed approximately 50% of the proteoglycans, the echogenicity level of ultrasound images of degraded cartilages was similar to that of controls. IRC and AIB parameters did not significantly vary. Histologic sections of degraded cartilage displayed no change in collagen fiber organization. The thickness mean values measured by ultrasound in PG-depleted groups were significantly higher than in controls, whereas no significant difference in thickness was detected by histological measurement. The increase in cartilage thickness may potentially be explained by a decrease of speed of sound in PG-depleted cartilages that is more likely subsequent to an increase of water content. Current results indicate that PG depletion has no significant effect on high frequency ultrasound backscattered from rat patellar cartilage. Ultrasound may provide information about variations of PG content via speed of sound measurement. Copyright 2002 OsteoArthritis Research Society International. Published by Elsevier Science Ltd. All rights reserved.

  20. The study on the mechanical characteristics of articular cartilage in simulated microgravity (United States)

    Niu, Hai-Jun; Wang, Qing; Wang, Yue-Xiang; Li, Ang; Sun, Lian-Wen; Yan, Yan; Fan, Fan; Li, De-Yu; Fan, Yu-Bo


    The microgravity environment of a long-term space flight may induce acute changes in an astronaut's musculo-skeletal systems. This study explores the effects of simulated microgravity on the mechanical characteristics of articular cartilage. Six rats underwent tail suspension for 14 days and six additional rats were kept under normal earth gravity as controls. Swelling strains were measured using high-frequency ultrasound in all cartilage samples subject to osmotic loading. Site-specific swelling strain data were used in a triphasic theoretical model of cartilage swelling to determine the uniaxial modulus of the cartilage solid matrix. No severe surface irregularities were found in the cartilage samples obtained from the control or tail-suspended groups. For the tail-suspended group, the thickness of the cartilage at a specified site, as determined by ultrasound echo, showed a minor decrease. The uniaxial modulus of articular cartilage at the specified site decreased significantly, from (6.31 ± 3.37)MPa to (5.05 ± 2.98)MPa ( p < 0.05). The histology-stained image of a cartilage sample also showed a reduced number of chondrocytes and decreased degree of matrix staining. These results demonstrated that the 14 d simulated microgravity induced significant effects on the mechanical characteristics of articular cartilage. This study is the first attempt to explore the effects of simulated microgravity on the mechanical characteristics of articular cartilage using an osmotic loading method and a triphasic model. The conclusions may provide reference information for manned space flights and a better understanding of the effects of microgravity on the skeletal system.

  1. Porous micropillar structures for retaining low surface tension liquids. (United States)

    Agonafer, Damena D; Lee, Hyoungsoon; Vasquez, Pablo A; Won, Yoonjin; Jung, Ki Wook; Lingamneni, Srilakshmi; Ma, Binjian; Shan, Li; Shuai, Shuai; Du, Zichen; Maitra, Tanmoy; Palko, James W; Goodson, Kenneth E


    The ability to manipulate fluid interfaces, e.g., to retain liquid behind or within porous structures, can be beneficial in multiple applications, including microfluidics, biochemical analysis, and the thermal management of electronic systems. While there are a variety of strategies for controlling the disposition of liquid water via capillarity, such as the use of chemically modified porous adhesive structures and capillary stop valves or surface geometric features, methods that work well for low surface tension liquids are far more difficult to implement. This study demonstrates the microfabrication of a silicon membrane that can retain exceptionally low surface tension fluorinated liquids against a significant pressure difference across the membrane via an array of porous micropillar structures. The membrane uses capillary forces along the triple phase contact line to maintain stable liquid menisci that yield positive working Laplace pressures. The micropillars have inner diameters and thicknesses of 1.5-3 μm and ∼1 μm, respectively, sustaining Laplace pressures up to 39 kPa for water and 9 kPa for Fluorinert™ (FC-40). A theoretical model for predicting the change in pressure as the liquid advances along the porous micropillar structure is derived based on a free energy analysis of the liquid meniscus with capped spherical geometry. The theoretical prediction was found to overestimate the burst pressure compared with the experimental measurements. To elucidate this deviation, transient numerical simulations based on the Volume of Fluid (VOF) were performed to explore the liquid pressure and evolution of meniscus shape under different flow rates (i.e., Capillary numbers). The results from VOF simulations reveal strong dynamic effects where the anisotropic expansion of liquid along the outer micropillar edge leads to an irregular meniscus shape before the liquid spills along the micropillar edge. These findings suggest that the analytical prediction

  2. Nanostructured 3D Constructs Based on Chitosan and Chondroitin Sulphate Multilayers for Cartilage Tissue Engineering

    NARCIS (Netherlands)

    Silva, J.M.; Georgi, Nicole; Costa, R.; Sher, P.; Reis, R L; van Blitterswijk, Clemens; Karperien, Hermanus Bernardus Johannes; Mano, J.F.


    Nanostructured three-dimensional constructs combining layer-by-layer technology (LbL) and template leaching were processed and evaluated as possible support structures for cartilage tissue engineering. Multilayered constructs were formed by depositing the polyelectrolytes chitosan (CHT) and

  3. Development of laminar flow control wing surface porous structure (United States)

    Klotzsche, M.; Pearce, W.; Anderson, C.; Thelander, J.; Boronow, W.; Gallimore, F.; Brown, W.; Matsuo, T.; Christensen, J.; Primavera, G.


    It was concluded that the chordwise air collection method, which actually combines chordwise and spanwise air collection, is the best of the designs conceived up to this time for full chord laminar flow control (LFC). Its shallower ducting improved structural efficiency of the main wing box resulting in a reduction in wing weight, and it provided continuous support of the chordwise panel joints, better matching of suction and clearing airflow requirements, and simplified duct to suction source minifolding. Laminar flow control on both the upper and lower surfaces was previously reduced to LFC suction on the upper surface only, back to 85 percent chord. The study concludes that, in addition to reduced wing area and other practical advantages, this system would be lighter because of the increase in effective structural wing thickness.

  4. Atomic and electronic structure of surfaces theoretical foundations

    CERN Document Server

    Lannoo, Michel


    Surfaces and interfaces play an increasingly important role in today's solid state devices. In this book the reader is introduced, in a didactic manner, to the essential theoretical aspects of the atomic and electronic structure of surfaces and interfaces. The book does not pretend to give a complete overview of contemporary problems and methods. Instead, the authors strive to provide simple but qualitatively useful arguments that apply to a wide variety of cases. The emphasis of the book is on semiconductor surfaces and interfaces but it also includes a thorough treatment of transition metals, a general discussion of phonon dispersion curves, and examples of large computational calculations. The exercises accompanying every chapter will be of great benefit to the student.

  5. Analysis and design of functional micro/nano structured surfaces (United States)

    Xu, Zhenzhen; Kong, Lingbao; Xu, Min


    In recent years, more and more attention has been paid to the bionic structure and functional materials. The theoretical research and fabricating ways of the Super-hydrophobic surface have sound achievements. However, the existing methods largely depend on the precision of the equipment and complex chemical substances, and it is hard to ensure the consistence of the material surface. Therefore, construction of microstructure on the surface of the material by using the method of mechanical processing to make the scale of the Super-hydrophobic surface to promote the popularization and application of Super-hydrophobic surface is of great significance. In order to put forward the innovative microstructure and to provide theoretical basis for the subsequent mechanical processing, based on the analysis of the classical theory of Super-hydrophobic, the super-hydrophobic film was by sol gel method. To explore the effects of different ratio of materials on the hydrophobicity, a micro/nano-structured super-hydrophobic coating was obtained by coating a film improved by hexamethyldisilazane (HMDS) after a film improved by polyethylene glycol (PEG) was coated. The microstructure of bilayer films is analyzed, and the double-layer film structure is simplified to design two kinds of microstructure models. For the design of the two models based on the Wenzel and Cassie equations, a roughness factor is adopted to establish the quantitative relationship between the contact angle and the microstructure parameters, and the microstructure parameters is also analyzed by using MATLAB software, and hence the optimized microstructure parameters is obtained.

  6. Strategies for Stratified Cartilage Bioprinting

    NARCIS (Netherlands)

    Schuurman, W.


    Multiple materials, cells and growth factors can be combined into one construct by the use of a state–of-the-art bioprinter. This technique may in the future make the fabrication of complete tissues or organs possible. In this thesis the feasibility of the bioprinting of cartilage and the

  7. Postnatal development of articular cartilage

    NARCIS (Netherlands)

    Turnhout, van M.C.


    Articular cartilage (AC) is the thin layer of tissue that covers the ends of the bones in the synovial joints in mammals. Functional adult AC has depth-dependent mechanical properties that are not yet present at birth. These depth-dependent mechanical properties in adult life are the result of a

  8. Femoral head cartilage disarticulation disorder (United States)

    Femoral head cartilage disarticulation disorder and necrosis is a major skeletal problem in broiler breeders since they are maintained for a long time in the farm. The etiology of this disease is not well understood. A field study was conducted to understand the basis of this metabolic disease. Six ...

  9. Visual evaluation of beef tenderness by using surface structural ...

    African Journals Online (AJOL)

    Kedibone KY. Modika


    Aug 1, 2015 ... Visual evaluation of beef tenderness by using surface structural observations and its relationship to meat colour. K.Y. Modika1,2#, L. Frylinck1, K.W. Moloto1, P.E. Strydom1,. P.H. Heinze1 & E.C. Webb2. 1 Department of Meat Science, Agricultural Research Council – Animal Production Institute, Private Bag ...

  10. Site-specific electronic structure of bacterial surface protein layers (United States)

    Vyalikh, D. V.; Kummer, K.; Kade, A.; Blüher, A.; Katzschner, B.; Mertig, M.; Molodtsov, S. L.


    We applied resonant photoemission and X-ray absorption spectroscopy for a detailed characterization of the valence electronic structure of the regular two-dimensional bacterial surface protein layer of Bacillus sphaericus NCTC 9602. Using this approach, we detected valence electron emission from specific chemical sites. In particular, it was found that electrons from the π clouds of aromatic systems make large contributions to the highest occupied molecular orbitals.

  11. Curved hierarchically micro-micro structured polypropylene surfaces by injection molding (United States)

    Mielonen, K.; Suvanto, M.; Pakkanen, T. A.


    Structural hierarchy of polymer surfaces has been of central interest due to its diverse surface functionalities. However, the research on hierarchically structured polymer surfaces has been focused on planar surfaces even though applications may also be variously curved. This study demonstrates the fabrication of curved rigid polymer surfaces with precisely controlled hierarchical microstructures. The surface structuration was made on an aluminum foil with a microworking robot, and polypropylene replicas were produced by injection molding. Depending on the mold structuration procedure, the curved mold can have either radially or vertically oriented structures. Both convex and concave curvatures were here applied to spherically and cylindrically curved surfaces. A simple structure protection technique was applied to support the structures during mechanical bending of the foil. The planar hierarchically microstructured polypropylene surfaces were characterized to exhibit superhydrophobicity, and similar structures were obtained on the curved surfaces. Introducing the curvature to the hierarchically structured surfaces may further widen the applicability of functionalized polymer surfaces.

  12. Biofabricated soft network composites for cartilage tissue engineering. (United States)

    Bas, Onur; De-Juan-Pardo, Elena M; Meinert, Christoph; D'Angella, Davide; Baldwin, Jeremy G; Bray, Laura J; Wellard, R Mark; Kollmannsberger, Stefan; Rank, Ernst; Werner, Carsten; Klein, Travis J; Catelas, Isabelle; Hutmacher, Dietmar W


    Articular cartilage from a material science point of view is a soft network composite that plays a critical role in load-bearing joints during dynamic loading. Its composite structure, consisting of a collagen fiber network and a hydrated proteoglycan matrix, gives rise to the complex mechanical properties of the tissue including viscoelasticity and stress relaxation. Melt electrospinning writing allows the design and fabrication of medical grade polycaprolactone (mPCL) fibrous networks for the reinforcement of soft hydrogel matrices for cartilage tissue engineering. However, these fiber-reinforced constructs underperformed under dynamic and prolonged loading conditions, suggesting that more targeted design approaches and material selection are required to fully exploit the potential of fibers as reinforcing agents for cartilage tissue engineering. In the present study, we emulated the proteoglycan matrix of articular cartilage by using highly negatively charged star-shaped poly(ethylene glycol)/heparin hydrogel (sPEG/Hep) as the soft matrix. These soft hydrogels combined with mPCL melt electrospun fibrous networks exhibited mechanical anisotropy, nonlinearity, viscoelasticity and morphology analogous to those of their native counterpart, and provided a suitable microenvironment for in vitro human chondrocyte culture and neocartilage formation. In addition, a numerical model using the p-version of the finite element method (p-FEM) was developed in order to gain further insights into the deformation mechanisms of the constructs in silico, as well as to predict compressive moduli. To our knowledge, this is the first study presenting cartilage tissue-engineered constructs that capture the overall transient, equilibrium and dynamic biomechanical properties of human articular cartilage.

  13. Antireflective surface structures on infrared optics (Conference Presentation) (United States)

    Busse, Lynda E.; Frantz, Jesse A.; Shaw, L. Brandon; Bayya, Shyam; Villalobos, Guillermo; Aggarwal, Ishwar D.; Sanghera, Jas S.


    Infrared-transmitting optics used in imaging systems have high refractive indices (n=1.4 to n > 3) that require antireflective (AR) coatings. These coatings have limitations in that they can delaminate in operational environments, which is a problem particularly for broadband coatings that consist of multiple layers of dissimilar materials. In addition, residual reflections within an imaging system can cause ghost reflections, degrading performance. Recently, new methods have been developed for fabrication of anti-reflective surface structures (ARSS) on optics that significantly reduce reflection losses at the surface. The ARSS approach provides a more robust solution by using surface structures built directly into the actual surface of the optics, without the need for a coating with extraneous materials. We present recent results that demonstrate superior ARSS performance on a variety of optics for use in the infrared spectral region. These materials have been successfully patterned with ARSS using reactive ion etching (RIE) or using photolithography and etching. We report on reflection losses as low as 0.02% for fused silica at 1.06 microns, and have also demonstrated low reflection losses for ARSS on germanium, spinel ceramic, and sapphire, all of which are important for mid- to long-wave infrared imaging applications.

  14. The Challenge in Using Mesenchymal Stromal Cells for Recellularization of Decellularized Cartilage. (United States)

    Huang, Zhao; Godkin, Owen; Schulze-Tanzil, Gundula


    Some decellularized musculoskeletal extracellular matrices (ECM)s derived from tissues such as bone, tendon and fibrocartilaginous meniscus have already been clinical use for tissue reconstruction. Repair of articular cartilage with its unique zonal ECM architecture and composition is still an unsolved problem, and the question is whether allogenic or xenogeneic decellularized cartilage ECM could serve as a biomimetic scaffold for this purpose.Hence, this survey outlines the present state of preparing decellularized cartilage ECM-derived scaffolds or composites for reconstruction of different cartilage types and of reseeding it particularly with mesenchymal stromal cells (MSCs).The preparation of natural decellularized cartilage ECM scaffolds hampers from the high density of the cartilage ECM and lacking interconnectivity of the rather small natural pores within it: the chondrocytes lacunae. Nevertheless, the reseeding of decellularized ECM scaffolds before implantation provided superior results compared with simply implanting cell-free constructs in several other tissues, but cartilage recellularization remains still challenging. Induced by cartilage ECM-derived scaffolds MSCs underwent chondrogenesis.Major problems to be addressed for the application of cell-free cartilage were discussed such as to maintain ECM structure, natural chemistry, biomechanics and to achieve a homogenous and stable cell recolonization, promote chondrogenic and prevent terminal differentiation (hypertrophy) and induce the deposition of a novel functional ECM. Some promising approaches were proposed including further processing of the decellularized ECM before recellularization of the ECM with MSCs, co-culturing of MSCs with chondrocytes and establishing bioreactor culture e.g. with mechanostimulation, flow perfusion pressure and lowered oxygen tension. Graphical Abstract Synopsis of tissue engineering approaches based on cartilage-derived ECM.

  15. Cartilage-selective genes identified in genome-scale analysis of non-cartilage and cartilage gene expression

    Directory of Open Access Journals (Sweden)

    Cohn Zachary A


    Full Text Available Abstract Background Cartilage plays a fundamental role in the development of the human skeleton. Early in embryogenesis, mesenchymal cells condense and differentiate into chondrocytes to shape the early skeleton. Subsequently, the cartilage anlagen differentiate to form the growth plates, which are responsible for linear bone growth, and the articular chondrocytes, which facilitate joint function. However, despite the multiplicity of roles of cartilage during human fetal life, surprisingly little is known about its transcriptome. To address this, a whole genome microarray expression profile was generated using RNA isolated from 18–22 week human distal femur fetal cartilage and compared with a database of control normal human tissues aggregated at UCLA, termed Celsius. Results 161 cartilage-selective genes were identified, defined as genes significantly expressed in cartilage with low expression and little variation across a panel of 34 non-cartilage tissues. Among these 161 genes were cartilage-specific genes such as cartilage collagen genes and 25 genes which have been associated with skeletal phenotypes in humans and/or mice. Many of the other cartilage-selective genes do not have established roles in cartilage or are novel, unannotated genes. Quantitative RT-PCR confirmed the unique pattern of gene expression observed by microarray analysis. Conclusion Defining the gene expression pattern for cartilage has identified new genes that may contribute to human skeletogenesis as well as provided further candidate genes for skeletal dysplasias. The data suggest that fetal cartilage is a complex and transcriptionally active tissue and demonstrate that the set of genes selectively expressed in the tissue has been greatly underestimated.

  16. Surface structure feature matching algorithm for cardiac motion estimation. (United States)

    Zhang, Zhengrui; Yang, Xuan; Tan, Cong; Guo, Wei; Chen, Guoliang


    Cardiac diseases represent the leading cause of sudden death worldwide. During the development of cardiac diseases, the left ventricle (LV) changes obviously in structure and function. LV motion estimation plays an important role for diagnosis and treatment of cardiac diseases. To estimate LV motion accurately for cine magnetic resonance (MR) cardiac images, we develop an algorithm by combining point set matching with surface structure features of myocardium. The structure features of myocardial wall are described by estimating the normal directions of points locating on the myocardium contours using an approximation approach. The Gaussian mixture model (GMM) of structure features is used to represent LV structure feature distribution. A new cost function is defined to represent the differences between two Gaussian mixture models, which are the GMM of structure features and the GMM of positions of two point sets. To optimize the cost function, its gradient is derived to use the Quasi-Newton (QN). Furthermore, to resolve the dis-convergence issue of Quasi-Newton for high-dimensional parameter space, Stochastic Gradient Descent (SGD) is used and SGD gradient is derived. Finally, the new cost function is solved by optimization combining SGD with QN. With the closed form expression of gradient, this paper provided a computationally efficient registration algorithm. Three public datasets are employed to verify the performance of our algorithm, including cardiac MR image sequences acquired from 33 subjects, 14 inter-subject heart cases, and the data obtained in MICCAI 2009s 3D Segmentation Challenge for Clinical Applications. We compare our results with those of the other point set registration methods for LV motion estimation. The obtained results demonstrate that our algorithm shows inherent statistical robustness, due to the combination of SGD and Quasi-Newton optimization. Furthermore, our method is shown to outperform other point set matching methods in the

  17. T2 mapping of articular cartilage of the glenohumeral joint at 3.0 T in healthy volunteers: a feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Yusuhn [Seoul National University Bundang Hospital, Department of Radiology, Seongnam-si, Gyeonggi-do (Korea, Republic of); Choi, Jung-Ah [Seoul National University Bundang Hospital, Department of Radiology, Seongnam-si, Gyeonggi-do (Korea, Republic of); Hallym University Dongtan Sacred Heart Hospital, Department of Radiology, Hwaseong, Gyeonggi-do (Korea, Republic of)


    The purpose of this study was to assess the T2 values of the glenohumeral joint cartilage in healthy asymptomatic individuals at 3.0 T and to analyze the T2 profile of the humeral cartilage. This prospective study was approved by our institutional review board and written informed consent was obtained. Thirteen subjects (mean age, 28.6 years; age range, 24-33 years) were included and underwent multiecho spin-echo T2-weighted MR imaging and T2 mapping was acquired. Regions of interest were placed on the humeral cartilage and glenoid cartilage on oblique coronal images. T2 profiles of humeral cartilage were measured from the bone-cartilage interface to the articular surface. Intra-observer agreement was analyzed using intraclass correlation coefficient (ICC). All 13 joints showed normal appearance on conventional T2-weighted images. The mean T2 values of humeral and glenoid cartilage were 50.5 ± 12.1 and 49.0 ± 9.9 ms, respectively. Intra-observer agreement was good, as determined by ICC (0.736). Longer T2 values were observed at the articular surface with a tendency to decrease toward the bone-cartilage interface. The mean cartilage T2 value was 69.03 ± 21.2 ms at the articular surface and 46.99 ± 19.6 ms at the bone-cartilage interface. T2 values of the glenohumeral joint cartilage were similar to reported values of cartilage in the knee. The T2 profile of normal humeral cartilage showed a spatial variation with an increase in T2 values from the subchondral bone to the articular surface. (orig.)

  18. Novel electrospun nanofibers of modified gelatin-tyrosine in cartilage tissue engineering. (United States)

    Agheb, Maria; Dinari, Mohammad; Rafienia, Mohammad; Salehi, Hossein


    In natural cartilage tissues, chondrocytes are linked to extracellular matrix (ECM) through cell-surface binding proteins. Surface modification of gelatin can provide a new generation of biopolymers and fibrous scaffolds with chemical, mechanical, and biological properties. In this study tyrosine protein and 1,2,3-triazole ring were utilized to functionalize gelatin without Cu catalyst. Their molecular structure was characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (1HNMR). Chemical cross-linkers such as glutaraldehyde (GA) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)/N-hydroxysulfosuccinimide (NHS) were used to electrospin the modified gelatin. The modification of gelatin and cross-linking effects were confirmed by scanning electron microscopy (SEM), contact angle measurement, and mechanical tests. MTT assay using chondrocyte cells showed cell viability of electrospun modified gelatin scaffolds. In vitro cell culture studies showed that electrospun engineered protein scaffolds would support the attachment and growth of cells. The results also showed that cross-linked nanofibers with EDC/NHS could be considered excellent matrices in cell adhesion and proliferation before electrospinning process and their potential substrate in tissue engineering applications, especially in the field of cartilage engineering. Copyright © 2016. Published by Elsevier B.V.

  19. Deformation of Nasal Septal Cartilage During Mastication (United States)

    Dayeh, Ayman A. Al; Rafferty, Katherine L.; Egbert, Mark; Herring, Susan W.


    The cartilaginous nasal septum plays a major role in structural integrity and growth of the face, but its internal location has made physiologic study difficult. By surgically implanting transducers in 10 miniature pigs (Sus scrofa), we recorded in vivo strains generated in the nasal septum during mastication and masseter stimulation. The goals were (1) to determine whether the cartilage should be considered as a vertical strut supporting the nasal cavity and preventing its collapse, or as a damper of stresses generated during mastication and (2) to shed light on the overall pattern of snout deformation during mastication. Strains were recorded simultaneously at the septo-ethmoid junction and nasofrontal suture during mastication. A third location in the anterior part of the cartilage was added during masseter stimulation and manipulation. Contraction of jaw closing muscles during mastication was accompanied by anteroposterior compressive strains (around −1,000 με) in the septo-ethmoid junction. Both the orientation and the magnitude of the strain suggest that the septum does not act as a vertical strut but may act in absorbing loads generated during mastication. The results from masseter stimulation and manipulation further suggest that the masticatory strain pattern arises from a combination of dorsal bending and/or shearing and anteroposterior compression of the snout. J. Morphol. PMID:19434723

  20. Injectable and 3D Bioprinted Polysaccharide Hydrogels: From Cartilage to Osteochondral Tissue Engineering. (United States)

    Radhakrishnan, Janani; Subramanian, Anuradha; Krishnan, Uma Maheswari; Sethuraman, Swaminathan


    Biomechanical performance of functional cartilage is executed by the exclusive anisotropic composition and spatially varying intricate architecture in articulating ends of diarthrodial joint. Osteochondral tissue constituting the articulating ends comprise superfical soft cartilage over hard subchondral bone sandwiching interfacial soft-hard tissue. The shock-absorbent, lubricating property of cartilage and mechanical stability of subchondral bone regions are rendered by extended chemical structure of glycosaminoglycans and mineral deposition, respectively. Extracellular matrix glycosaminoglycans analogous polysaccharides are major class of hydrogels investigated for restoration of functional cartilage. Recently, injectable hydrogels have gained momentum as it offers patient compliance, tunable mechanical properties, cell deliverability, and facile administration at physiological condition with long-term functionality and hyaline cartilage construction. Interestingly, facile modifiable functional groups in carbohydrate polymers impart tailorability of desired physicochemical properties and versatile injectable chemistry for the development of highly potent biomimetic in situ forming scaffold. The scaffold design strategies have also evolved from single component to bi- or multilayered and graded constructs with osteogenic properties for deep subchondral regeneration. This review highlights the significance of polysaccharide structure-based functions in engineering cartilage tissue, injectable chemistries, strategies for combining analogous matrices with cells/stem cells and biomolecules and multicomponent approaches for osteochondral mimetic constructs. Further, the rheology and precise spatiotemporal positioning of cells in hydrogel bioink for rapid prototyping of complex three-dimensional anisotropic cartilage have also been discussed.

  1. Chitosan-Based Hyaluronic Acid Hybrid Polymer Fibers as a Scaffold Biomaterial for Cartilage Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Shintarou Yamane


    Full Text Available An ideal scaffold material is one that closely mimics the natural environment in the tissue-specific extracellular matrix (ECM. Therefore, we have applied hyaluronic acid (HA, which is a main component of the cartilage ECM, to chitosan as a fundamental material for cartilage regeneration. To mimic the structural environment of cartilage ECM, the fundamental structure of a scaffold should be a three-dimensional (3D system with adequate mechanical strength. We structurally developed novel polymer chitosan-based HA hybrid fibers as a biomaterial to easily fabricate 3D scaffolds. This review presents the potential of a 3D fabricated scaffold based on these novel hybrid polymer fibers for cartilage tissue engineering.

  2. hWJECM-Derived Oriented Scaffolds with Autologous Chondrocytes for Rabbit Cartilage Defect Repairing. (United States)

    Zhao, Peng; Liu, Shuyun; Bai, Yuhe; Lu, Shibi; Peng, Jiang; Zhang, Li; Huang, Jingxiang; Zhao, Bin; Xu, Wenjing; Guo, Quanyi


    Previously, we synthesized an articular cartilage extracellular matrix (ECM)-derived oriented scaffold for cartilage tissue engineering, which was biomimetic in terms of structure and biochemical composition. However, the limit resource of the cartilage-derived ECM is a hindrance for its application. In this study, we developed a new material for cartilage tissue engineering-human umbilical cord Wharton's jelly-derived ECM (hWJECM). The hWJECM has an abundant resource and similar biochemistry with cartilage ECM, and the use of it is not associated with ethical controversy. We adopted the method previously used in cartilage ECM-derived oriented scaffold preparation to generate the oriented hWJECM-derived scaffold, and the scaffold properties were tested in vitro and in vivo. The three-dimensional scaffold has a porous and well-oriented structure, with a mean pore diameter of ∼104 μm. Scanning electron microscopy and cell viability staining results demonstrated that the oriented scaffold has good biocompatibility and cell alignment. In addition, we used functional autologous chondrocytes to seed the hWJECM-derived oriented scaffold and tested the efficacy of the cell-scaffold constructs to repair the full-thickness articular cartilage defect in a rabbit model. Defects of 4 mm diameter were generated in the patellar grooves of the femurs of both knees and were implanted with chondrocyte-scaffold constructs (group A) or scaffolds alone (group B); rabbits with untreated defects were used as a control (group C). Six months after surgery, all defects in group A were filled completely with repaired tissue, and most of which were hyaline cartilage. In contrast, the defects in group B were filled partially with repaired tissue, and approximately half of these repaired tissues were hyaline cartilage. The defects in group C were only filled with fibrotic tissue. Histological grading score of group A was lower than those of groups B and C. Quantification of

  3. A study of crystalline biomaterials for articular cartilage bioengineering

    Energy Technology Data Exchange (ETDEWEB)

    Gross-Aviv, Talia [Department of Biotechnology Engineering, Ben-Gurion University of the Negev, Beer Sheva, 84105 (Israel)], E-mail:; DiCarlo, Bryan B. [Department of Bioengineering, Rice University, Houston, TX 77003 (United States)], E-mail:; French, Margaret M. [Department of Bioengineering, Rice University, Houston, TX 77003 (United States)], E-mail:; Athanasiou, Kyriacos A. [Department of Bioengineering, Rice University, Houston, TX 77003 (United States)], E-mail:; Vago, Razi [Department of Biotechnology Engineering, Ben-Gurion University of the Negev, Beer Sheva, 84105 (Israel)], E-mail:


    This study examines the suitability of marine origin coral species, Porites lutea (POR) and the hydrozoan Millepora dichotoma (MIL), for use as novel three dimensional growth matrices in the field of articular cartilage tissue engineering. Therefore, mesenchymal stem cells (MSCs) and chondrocytes were grown on the skeletal material obtained from each of these two organisms to investigate their potential use as three dimensional scaffolding for cartilage tissue growth. Chondrogenic induction of MSCs was achieved by addition of transforming growth factor-{beta}1 (TGF-{beta}1) and insulin growth factor-I (IGF-I). Cell adherence, proliferation, differentiation and tissue development were investigated through six weeks of culture. Cartilage tissue growth and chondrocytic phenotype maintenance of each cell type were examined by cell morphology, histochemical analyses, expression of collagen type II and quantitative measures of glycosaminoglycan (GAG) content. The MSCs and the chondrocytes were shown good adherence to the scaffolds and maintenance of the chondrocytic phenotype in the initial stages of culture. However after two weeks of culture on MIL and three weeks on POR these cultures began to exhibit signs of further differentiation and phenotypic loss. The shown results indicated that POR was a better substrate for chondrocytes phenotype maintenance than MIL. We believe that surface modification of POR combined with mechanical stimuli will provide a suitable environment for chondrogenic phenotype maintenance. Further investigation of POR and other novel coralline biomatrices is indicated and warranted in the field of cartilage tissue engineering applications.

  4. 3.0 T MR imaging of the ankle: Axial traction for morphological cartilage evaluation, quantitative T2 mapping and cartilage diffusion imaging—A preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Jungmann, Pia M., E-mail: [Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich (Germany); Baum, Thomas, E-mail: [Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich (Germany); Schaeffeler, Christoph, E-mail: [Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich (Germany); Musculoskeletal Imaging, Kantonsspital Graubuenden, Loestrasse 170, CH-7000 Chur (Switzerland); Sauerschnig, Martin, E-mail: [Department of Trauma Surgery, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich (Germany); Department of Orthopaedic Sports Medicine, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich (Germany); Brucker, Peter U., E-mail: [Department of Orthopaedic Sports Medicine, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich (Germany); Mann, Alexander, E-mail: [Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich (Germany); Department of Orthopaedic Sports Medicine, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich (Germany); Ganter, Carl, E-mail: [Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich (Germany); Bieri, Oliver, E-mail: [Division of Radiological Physics, Department of Radiology, University of Basel Hospital, Petersgraben 4, 4031 Basel (Switzerland); and others


    Highlights: • Axial traction is applicable during high resolution MR imaging of the ankle. • Axial traction during MR imaging oft the ankle improves cartilage surface delineation of the individual tibial and talar cartilage layer for better morphological evaluation without the need of intraarticular contrast agent application. • Coronal T1-weighted MR images with a driven equilibrium pulse performed best. • Axial traction during MR imaging of the ankle facilitates compartment discrimination for segmentation purposes resulting in better reproducibility. - Abstract: Purpose: To determine the impact of axial traction during high resolution 3.0 T MR imaging of the ankle on morphological assessment of articular cartilage and quantitative cartilage imaging parameters. Materials and Methods: MR images of n = 25 asymptomatic ankles were acquired with and without axial traction (6 kg). Coronal and sagittal T1-weighted (w) turbo spin echo (TSE) sequences with a driven equilibrium pulse and sagittal fat-saturated intermediate-w (IMfs) TSE sequences were acquired for morphological evaluation on a four-point scale (1 = best, 4 = worst). For quantitative assessment of cartilage degradation segmentation was performed on 2D multislice-multiecho (MSME) SE T2, steady-state free-precession (SSFP; n = 8) T2 and SSFP diffusion-weighted imaging (DWI; n = 8) images. Wilcoxon-tests and paired t-tests were used for statistical analysis. Results: With axial traction, joint space width increased significantly and delineation of cartilage surfaces was rated superior (P < 0.05). Cartilage surfaces were best visualized on coronal T1-w images (P < 0.05). Differences for cartilage matrix evaluation were smaller. Subchondral bone evaluation, motion artifacts and image quality were not significantly different between the acquisition methods (P > 0.05). T2 values were lower at the tibia than at the talus (P < 0.001). Reproducibility was better for images with axial traction. Conclusion

  5. Polymer masks for structured surface and plasma etching

    Energy Technology Data Exchange (ETDEWEB)

    Vital, Alexane [Centre de Recherche sur la Matière Divisée (CRMD), 1b rue de la Férollerie, F45071 Orléans Cedex (France); Groupe de Recherches sur l’Énergétique des Milieux Ionisés (GREMI), Polytech’Orléans, 14 rue d’Issoudun, B.P. 6744, F45067 Orléans Cedex 2 (France); Vayer, Marylène, E-mail: [Centre de Recherche sur la Matière Divisée (CRMD), 1b rue de la Férollerie, F45071 Orléans Cedex (France); Sinturel, Christophe [Centre de Recherche sur la Matière Divisée (CRMD), 1b rue de la Férollerie, F45071 Orléans Cedex (France); Tillocher, Thomas; Lefaucheux, Philippe; Dussart, Rémi [Groupe de Recherches sur l’Énergétique des Milieux Ionisés (GREMI), Polytech’Orléans, 14 rue d’Issoudun, B.P. 6744, F45067 Orléans Cedex 2 (France)


    Graphical abstract: - Highlights: • Sub-micrometric silicon structures were prepared by cryogenic plasma etching. • Polymer templates based on phase-separated films of PS/PLA were used. • Silica structured masks were prepared by filling the polymer templates. • Etching of underlying silicon through silica templates gave original structures. - Abstract: Silica and silicon structures have been prepared at the sub-micrometer length-scale, using laterally phase-separated thin films of poly(styrene) (PS) and poly(lactic acid) (PLA) homopolymer blends. The selective removal of one polymer and the filling of the released space by silica precursor solution led, after calcination, to silica structures on silicon such as arrays of bowl-shape features or pillars, layers with through or non-through cylindrical holes, which has not been observed for some of them. The control of the morphology of the initial polymer film was a key point to achieve such type of structures. Particularly relevant was the use of solvent vapor annealing (vs thermal annealing) of the initial spin-coated films that favored and stabilized laterally phase-separated morphologies. Characteristic dimension of the domains were shown to be coupled with the thickness of the film, thinner films giving smaller domain sizes. Despite a relatively high incompatibility of the two polymers, a macro-phase separation was prevented in all the studied conditions. Sub-micrometric domains were formed, and for the thinner films, nanometric domains as small as 74 nm in size can be obtained. The silica structures formed by the infiltration of the polymer templates were used as hard masks for the cryogenic etching of underlying silicon. New structured surfaces, arrays of silicon pillars which can be plain or hollow at the upper part or arrays of cylindrical holes were formed. A selectivity as high as 21 was obtained using this type of mask for 1.5 μm deep holes having a typical diameter of 200 nm.

  6. Changes in growth patterns in mouse condylar cartilage associated with skeletal maturation and senescence

    Energy Technology Data Exchange (ETDEWEB)

    Livne, E.; Weiss, A.; Silbermann, M. (Technion-Israel Inst. of Tech., Haifa (Israel))

    The squamoso-mandibular joint (SMJ) represents one of the most active joints in the mouse. In the young animal the main function of condylar cartilage in the SMJ is to serve as a growth center for the developing mandible. This first phase of skeletal growth lasts up to the age of 6-8 weeks, and is manifested by appositional growth of cartilage followed by endochondral ossification. Thereafter, the condylar cartilage gradually changes its function and serves mainly as an articulating surface for the joint. Consequently, the cartilage changes from a calcifying hyaline cartilage to a fibrous non-calcifying cartilage. The latter phase lasts through the stage of maturation (6 months of age) and it is manifested by a combination of appositional and interstitial patterns of cellular growth. Thereafter, the third phase develops which is characterized by degenerative changes that typify the aging process. In vivo autoradiography with ({sup 3}H)-thymidine indicated that in the very young animal labeled cells are confined to the chondroprogenitor (proliferative) zone of the condylar cartilage. With maturation, the dimension of this zone as well as the number of labeled cells decrease, so that by 3 months of age the labeling index decreases by 30%. By the age of 6, 12 and 18 months, almost no cells take up the radioisotope while the total number of cells declines. During senescence only a very limited interstitial growth is taking place, a feature that might be associated with the repair processes that accompany the onset of osteoarthritic lesions.

  7. Hydrogel design for cartilage tissue engineering: a case study with hyaluronic acid. (United States)

    Kim, Iris L; Mauck, Robert L; Burdick, Jason A


    Hyaline cartilage serves as a low-friction and wear-resistant articulating surface in load-bearing, diarthrodial joints. Unfortunately, as the avascular, alymphatic nature of cartilage significantly impedes the body's natural ability to regenerate, damage resulting from trauma and osteoarthritis necessitates repair attempts. Current clinical methods are generally limited in their ability to regenerate functional cartilage, and so research in recent years has focused on tissue engineering solutions in which the regeneration of cartilage is pursued through combinations of cells (e.g., chondrocytes or stem cells) paired with scaffolds (e.g., hydrogels, sponges, and meshes) in conjunction with stimulatory growth factors and bioreactors. A variety of synthetic and natural materials have been employed, most commonly in the form of hydrogels, and these systems have been tuned for optimal nutrient diffusion, connectivity of deposited matrix, degradation, soluble factor delivery, and mechanical loading for enhanced matrix production and organization. Even with these promising advances, the complex mechanical properties and biochemical composition of native cartilage have not been achieved, and engineering cartilage tissue still remains a significant challenge. Using hyaluronic acid hydrogels as an example, this review will follow the progress of material design specific to cartilage tissue engineering and propose possible future directions for the field. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Genipin crosslinking of cartilage enhances resistance to biochemical degradation and mechanical wear. (United States)

    McGann, Megan E; Bonitsky, Craig M; Jackson, Mariah L; Ovaert, Timothy C; Trippel, Stephen B; Wagner, Diane R


    Collagen crosslinking enhances many beneficial properties of articular cartilage, including resistance to chemical degradation and mechanical wear, but many crosslinking agents are cytotoxic. The purpose of this study was to evaluate the effectiveness of genipin, a crosslinking agent with favorable biocompatibility and cytotoxicity, as a potential treatment to prevent the degradation and wear of articular cartilage. First, the impact of genipin concentration and treatment duration on the viscoelastic properties of bovine articular cartilage was quantified. Next, two short-term (15 min) genipin crosslinking treatments were chosen, and the change in collagenase digestion, cartilage wear, and the friction coefficient of the tissue with these treatments was measured. Finally, chondrocyte viability after exposure to these genipin treatments was assessed. Genipin treatment increased the stiffness of healthy, intact cartilage in a dose-dependent manner. The 15-min crosslinking treatments improved cartilage's resistance to both chemical degradation, particularly at the articular surface, and to damage due to mechanical wear. These enhancements were achieved without sacrificing the low coefficient of friction of the tissue and at a genipin dose that preserved chondrocyte viability. The results of this study suggest that collagen crosslinking via genipin may be a promising preventative treatment to slow the degradation of cartilage. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  9. Simultaneous measurements of top surface and its underlying film surfaces in multilayer film structure. (United States)

    Ghim, Young-Sik; Rhee, Hyug-Gyo; Davies, Angela


    With the growth of 3D packaging technology and the development of flexible, transparent electrodes, the use of multilayer thin-films is steadily increasing throughout high-tech industries including semiconductor, flat panel display, and solar photovoltaic industries. Also, this in turn leads to an increase in industrial demands for inspection of internal analysis. However, there still remain many technical limitations to overcome for measurement of the internal structure of the specimen without damage. In this paper, we propose an innovative optical inspection technique for simultaneous measurements of the surface and film thickness corresponding to each layer of multilayer film structures by computing the phase and reflectance over a wide range of wavelengths. For verification of our proposed method, the sample specimen of multilayer films was fabricated via photolithography process, and the surface profile and film thickness of each layer were measured by two different techniques of a stylus profilometer and an ellipsometer, respectively. Comparison results shows that our proposed technique enables simultaneous measurements of the top surface and its underlying film surfaces with high precision, which could not be measured by conventional non-destructive methods.

  10. Structure of aqueous electrolyte solutions near a hydrophobic surface

    Directory of Open Access Journals (Sweden)



    Full Text Available The structure of aqueous solutions of 1:1 salts (KCl, NaCl, KF,and CsI near a hydrophobic surface is analysed using the angle-dependent integral equation theory. Water molecules are taken to be hard spheres imbedded with multipolar moments including terms up to octupole order, and hard spherical ions are immersed in this model water. The many-body interactions associated with molecular polarizability are treated at the self-consistent mean field level. The effects of cationic and anionic sizes and salt concentration in the bulk are discussed in detail. As the salt concentration increases, the layer of water molecules next to the surface becomes denser but its orientational order remains almost unchanged. The concentration of each ion at the surface can be drastically different from that in the bulk. Asa striking example, at sufficiently low salt concentrations, the concentration of I- is about 500 times higher than that of F- at the surface.

  11. Preservation of Archaeal Surface Layer Structure During Mineralization (United States)

    Kish, Adrienne; Miot, Jennyfer; Lombard, Carine; Guigner, Jean-Michel; Bernard, Sylvain; Zirah, Séverine; Guyot, François


    Proteinaceous surface layers (S-layers) are highly ordered, crystalline structures commonly found in prokaryotic cell envelopes that augment their structural stability and modify interactions with metals in the environment. While mineral formation associated with S-layers has previously been noted, the mechanisms were unconstrained. Using Sulfolobus acidocaldarius a hyperthermophilic archaeon native to metal-enriched environments and possessing a cell envelope composed only of a S-layer and a lipid cell membrane, we describe a passive process of iron phosphate nucleation and growth within the S-layer of cells and cell-free S-layer “ghosts” during incubation in a Fe-rich medium, independently of metabolic activity. This process followed five steps: (1) initial formation of mineral patches associated with S-layer; (2) patch expansion; (3) patch connection; (4) formation of a continuous mineral encrusted layer at the cell surface; (5) early stages of S-layer fossilization via growth of the extracellular mineralized layer and the mineralization of cytosolic face of the cell membrane. At more advanced stages of encrustation, encrusted outer membrane vesicles are formed, likely in an attempt to remove damaged S-layer proteins. The S-layer structure remains strikingly well preserved even upon the final step of encrustation, offering potential biosignatures to be looked for in the fossil record.

  12. Response surface reconciliation method of bolted joints structure

    Directory of Open Access Journals (Sweden)

    Yunus Mohd Azmi


    Full Text Available Structural joining methods such as bolted joints are commonly used for the assembly of structural components due to their simplicity and easy maintenance. Understandably, the dynamic characteristic of bolted joined structure is mainly influenced by the properties of their joints such as preload on the bolts and joints stiffness which alter the measured dynamics response of the structure. Therefore, the need to include the local effect of the bolted joints into the numerical model of the bolted joined structure is vitally important in order to represent the model accurately. In this paper, a few types of connector elements that can be used to represent the bolted joints such as CBAR, CBEAM and CELAS have been investigated numerically and experimentally. The initial numerical results of these element connectors are compared with the experimental results in term of natural frequencies and mode shapes. The comparative evaluation of numerical and the experimental data are performed in order to provide some insights of inaccuracies in the numerical model due to invalid assumption in the numerical modelling such as geometry, material properties, and boundary conditions. The discrepancies between both results (numerical and experimental data are then corrected using the response surface reconciliation method (RSRM through which the finite element model is altered in order to provide closer agreement with the measured data so that it can be used for subsequence analysis.

  13. Knee cartilage morphologic characteristics and muscle status of professional weight lifters and sprinters: a magnetic resonance imaging study. (United States)

    Gratzke, Christian; Hudelmaier, Martin; Hitzl, Wolfgang; Glaser, Christian; Eckstein, Felix


    Whereas muscle and bone mass have been shown to strongly depend on mechanical stimulation (loading history), this relationship has not been established for articular cartilage. Subjects with high muscle strength display thicker knee cartilage and larger joint surface areas than nonathletic volunteers, and knee cartilage morphologic characteristics correlate more strongly with muscle force than with muscle cross-sectional areas. Cross-sectional study; Level of evidence, 3. Fourteen young, healthy adult professional athletes (7 weight lifters and 7 bobsled sprinters) were examined and compared with 14 adult nonathletic volunteers who had never performed strength training. Muscle moments were measured with a dynamometer and muscle cross-sectional areas and knee cartilage morphologic characteristics with magnetic resonance imaging. Weight lifters and sprinters displayed significantly (P < .001) larger extensor muscle moments and cross-sectional areas. They showed significantly greater (P < .01) patellar cartilage thickness than nonathletic volunteers (+14% [95% confidence interval, 6% to 22%] and +17% [95% confidence interval, 9% to 26%], respectively) but no significant differences in the cartilage thickness of the other knee joint cartilage plates or joint surface areas. Muscle moments did not correlate more strongly with knee cartilage volume or thickness than muscle cross-sectional areas of the thigh. Direct measurements of muscle forces do not predict cartilage thickness more accurately than muscle cross-sectional areas. These findings suggest that cartilage thickness has much less ability, if any, to adapt to mechanical loading than muscle. Large cohorts of athletes will need to be studied to detect potentially significant differences in cartilage versus nonathletic controls.

  14. Roles of the Fibrous Superficial Zone in the Mechanical Behavior of TMJ Condylar Cartilage. (United States)

    Ruggiero, Leonardo; Zimmerman, Brandon K; Park, Miri; Han, Lin; Wang, Liyun; Burris, David L; Lu, X Lucas


    In temporomandibular joints (TMJs), the cartilage on the condylar head displays a unique ultrastructure with a dense layer of type I collagen in the superficial zone, different from hyaline cartilage in other joints. This study aims to elucidate the roles of this fibrous zone in the mechanical behaviors, particularly lubrication, of TMJ under physiological loading regimes. Mechanical tests on porcine condylar cartilage demonstrated that the superficial and middle-deep zones exhibit tension-compression nonlinearity. The tensile and compressive moduli of the superficial zone are 30.73 ± 12.97 and 0.028 ± 0.016 MPa, respectively, while those for the middle-deep zone are 2.43 ± 1.75 and 0.14 ± 0.09 MPa. A nonlinear finite element model of condylar cartilage was built to simulate sliding of a spherical probe over the articular surface. The presence of the superficial zone significantly promoted interstitial fluid pressurization (IFP) inside the loaded cartilage and reduced the friction force on the surface, compared to the case without the superficial zone. Finite element simulations showed that IFP depends on sliding speed but not normal load, which matches the experimental results. This study revealed the presence of the fibrous zone can significantly reduce the deformation of condylar cartilage under compression and the friction force on its surface during sliding.

  15. Origin and function of cartilage stem/progenitor cells in osteoarthritis. (United States)

    Jiang, Yangzi; Tuan, Rocky S


    Articular cartilage is a physiologically non-self-renewing avascular tissue with a singular cell type, the chondrocyte, which functions as the load-bearing surface of the arthrodial joint. Injury to cartilage often progresses spatiotemporally from the articular surface to the subchondral bone, leading to development of degenerative joint diseases such as osteoarthritis (OA). Although lacking intrinsic reparative ability, articular cartilage has been shown to contain a population of stem cells or progenitor cells, similar to those found in many other adult tissues, that are thought to be involved in the maintenance of tissue homeostasis. These so-called cartilage-derived stem/progenitor cells (CSPCs) have been observed in human, equine and bovine articular cartilage, and have been identified, isolated and characterized on the basis of expression of stem-cell-related surface markers, clonogenicity and multilineage differentiation ability. However, the origin and functions of CSPCs are incompletely understood. We review here the current status of CSPC research and discuss the possible origin of these cells, what role they might have in cartilage repair, and their therapeutic potential in OA.

  16. Deformable structure registration of bladder through surface mapping. (United States)

    Xiong, Li; Viswanathan, Akila; Stewart, Alexandra J; Haker, Steven; Tempany, Clare M; Chin, Lee M; Cormack, Robert A


    Cumulative dose distributions in fractionated radiation therapy depict the dose to normal tissues and therefore may permit an estimation of the risk of normal tissue complications. However, calculation of these distributions is highly challenging because of interfractional changes in the geometry of patient anatomy. This work presents an algorithm for deformable structure registration of the bladder and the verification of the accuracy of the algorithm using phantom and patient data. In this algorithm, the registration process involves conformal mapping of genus zero surfaces using finite element analysis, and guided by three control landmarks. The registration produces a correspondence between fractions of the triangular meshes used to describe the bladder surface. For validation of the algorithm, two types of balloons were inflated gradually to three times their original size, and several computerized tomography (CT) scans were taken during the process. The registration algorithm yielded a local accuracy of 4 mm along the balloon surface. The algorithm was then applied to CT data of patients receiving fractionated high-dose-rate brachytherapy to the vaginal cuff, with the vaginal cylinder in situ. The patients' bladder filling status was intentionally different for each fraction. The three required control landmark points were identified for the bladder based on anatomy. Out of an Institutional Review Board (IRB) approved study of 20 patients, 3 had radiographically identifiable points near the bladder surface that were used for verification of the accuracy of the registration. The verification point as seen in each fraction was compared with its predicted location based on affine as well as deformable registration. Despite the variation in bladder shape and volume, the deformable registration was accurate to 5 mm, consistently outperforming the affine registration. We conclude that the structure registration algorithm presented works with reasonable accuracy and

  17. Evaluation of multilayered pavement structures from measurements of surface waves (United States)

    Ryden, N.; Lowe, M.J.S.; Cawley, P.; Park, C.B.


    A method is presented for evaluating the thickness and stiffness of multilayered pavement structures from guided waves measured at the surface. Data is collected with a light hammer as the source and an accelerometer as receiver, generating a synthetic receiver array. The top layer properties are evaluated with a Lamb wave analysis. Multiple layers are evaluated by matching a theoretical phase velocity spectrum to the measured spectrum. So far the method has been applied to the testing of pavements, but it may also be applicable in other fields such as ultrasonic testing of coated materials. ?? 2006 American Institute of Physics.

  18. Plasmonic nanopillar structures for surface-enhanced raman scattering applications

    DEFF Research Database (Denmark)

    Rindzevicius, Tomas; Schmidt, Michael Stenbæk; Wu, Kaiyu


    experimentally and theoretically. Simulations show that that a single Agcoated NP supports two LSPR modes, i.e. the particle mode and the Ag cap resonant cavity mode. The Ag cap resonant cavity mode contributes most to the enhancement of the Raman scattering signal. The electric field distribution calculations...... have been utilized in surfaceenhanced Raman spectroscopy (SERS) for biological and chemical sensing. We present Au nanopillar (NP) SERS structures that are excellent for molecular detection. The NP structures can be fabricated using a simple two-step process. We analyze NP optical properties...... show that the EM hot spots are located at the bottom of the Ag cap which is important observation for practical SERS sensing. Reproducible and repeatable SERS signal intensities can be obtained across large surface areas (>mm2). Application examples include detection of TAMRA-labeled vasopressin...

  19. Cell patterning via laser micro/nano structured silicon surfaces. (United States)

    Yiannakou, Ch; Simitzi, Ch; Manousaki, A; Fotakis, C; Ranella, A; Stratakis, E


    The surface topography of biomaterials can have an important impact on cellular adhesion, growth and proliferation. Apart from the overall roughness, the detailed morphological features, at all length scales, significantly affect the cell-biomaterial interactions in a plethora of applications including structural implants, tissue engineering scaffolds and biosensors. In this study, we present a simple, one-step direct laser patterning technique to fabricate nanoripples and dual-rough hierarchical micro/nano structures to control SW10 cell attachment and migration. It is shown that, depending on the laser processing conditions, distinct cell-philic or cell-repellant patterned areas can be attained with a desired motif. We envisage that our technique could enable spatial patterning of cells in a controllable manner, giving rise to advanced capabilities in cell biology research.

  20. Healing Osteoarthritis: Engineered Proteins Created for Therapeutic Cartilage Regeneration

    Directory of Open Access Journals (Sweden)

    Kevin M. Cherry


    Full Text Available Millions of people worldwide are afflicted with painfulosteoarthritis, which is characterized by degradationof articular cartilage found in major joints such as thehip or knee. Symptoms include inflammation, pain,and decreased mobility. Because cartilage has a limitedability to self-heal, researchers have focused efforts onmethods that trigger cartilage regeneration. Our approachis to develop an injectable, protein-based hydrogel withmechanical properties analogous to healthy articularcartilage. The hydrogel provides an environment for cellgrowth and stimulates new tissue formation. We utilizedrecombinant DNA technology to create multifunctional,elastomeric proteins. The recombinant proteins weredesigned with biologically active domains to influence cellbehavior and resilin structural domains that mimic thestiffness of native cartilage. Resilin, a protein found in thewing and leg joints of mosquitoes, provided inspiration forthe mechanical domain in the recombinant protein. Thenew resilin-based protein was expressed in E. coli bacteria.Forming hydrogels requires a large quantity of engineeredprotein, so parameters such as bacterial host, incubationtemperature, expression time, and induction method wereoptimized to increase the protein yield. Using salt toprecipitate the protein and exploiting resilin’s heat stability,27 mg/L of recombinant protein was recovered at 95%purity. The protein expression and purification protocolswere established by analyzing experimental samples onSDS-PAGE gels and by Western blotting. The mechanicalproperties and interactions with stem cells are currentlybeing evaluated to assess the potential of the resilin-basedhydrogel as a treatment for osteoarthritis.

  1. Preclinical Studies for Cartilage Repair (United States)

    Hurtig, Mark B.; Buschmann, Michael D.; Fortier, Lisa A.; Hoemann, Caroline D.; Hunziker, Ernst B.; Jurvelin, Jukka S.; Mainil-Varlet, Pierre; McIlwraith, C. Wayne; Sah, Robert L.; Whiteside, Robert A.


    Investigational devices for articular cartilage repair or replacement are considered to be significant risk devices by regulatory bodies. Therefore animal models are needed to provide proof of efficacy and safety prior to clinical testing. The financial commitment and regulatory steps needed to bring a new technology to clinical use can be major obstacles, so the implementation of highly predictive animal models is a pressing issue. Until recently, a reductionist approach using acute chondral defects in immature laboratory species, particularly the rabbit, was considered adequate; however, if successful and timely translation from animal models to regulatory approval and clinical use is the goal, a step-wise development using laboratory animals for screening and early development work followed by larger species such as the goat, sheep and horse for late development and pivotal studies is recommended. Such animals must have fully organized and mature cartilage. Both acute and chronic chondral defects can be used but the later are more like the lesions found in patients and may be more predictive. Quantitative and qualitative outcome measures such as macroscopic appearance, histology, biochemistry, functional imaging, and biomechanical testing of cartilage, provide reliable data to support investment decisions and subsequent applications to regulatory bodies for clinical trials. No one model or species can be considered ideal for pivotal studies, but the larger animal species are recommended for pivotal studies. Larger species such as the horse, goat and pig also allow arthroscopic delivery, and press-fit or sutured implant fixation in thick cartilage as well as second look arthroscopies and biopsy procedures. PMID:26069576

  2. Supporting Biomaterials for Articular Cartilage Repair (United States)

    Duarte Campos, Daniela Filipa; Drescher, Wolf; Rath, Björn; Tingart, Markus


    Orthopedic surgeons and researchers worldwide are continuously faced with the challenge of regenerating articular cartilage defects. However, until now, it has not been possible to completely mimic the biological and biochemical properties of articular cartilage using current research and development approaches. In this review, biomaterials previously used for articular cartilage repair research are addressed. Furthermore, a brief discussion of the state of the art of current cell printing procedures mimicking native cartilage is offered in light of their use as future alternatives for cartilage tissue engineering. Inkjet cell printing, controlled deposition cell printing tools, and laser cell printing are cutting-edge techniques in this context. The development of mimetic hydrogels with specific biological properties relevant to articular cartilage native tissue will support the development of improved, functional, and novel engineered tissue for clinical application. PMID:26069634

  3. Cartilage regeneration and repair testing in a surrogate large animal model. (United States)

    Simon, Timothy M; Aberman, Harold M


    The aging human population is experiencing increasing numbers of symptoms related to its degenerative articular cartilage (AC), which has stimulated the investigation of methods to regenerate or repair AC. However, the seemingly inherent limited capacity for AC to regenerate persists to confound the various repair treatment strategies proposed or studied. Animal models for testing AC implant devices and reparative materials are an important and required part of the Food and Drug Administration approval process. Although final testing is ultimately performed in humans, animal testing allows for a wider range of parameters and combinations of test materials subjected to all the biological interactions of a living system. We review here considerations, evaluations, and experiences with selection and use of animal models and describe two untreated lesion models useful for testing AC repair strategies. These created lesion models, one deep (6 mm and through the subchondral plate) the other shallow (to the level of the subchondral bone plate) were placed in the middle one-third of the medial femoral condyle of the knee joints of goats. At 1-year neither the deep nor the shallow full-thickness chondral defects generated a repair that duplicated natural AC. Moreover, progressive deleterious changes occurred in the AC surrounding the defects. There are challenges in translation from animals to humans as anatomy and structures are different and immobilization to protect delicate repairs can be difficult. The tissues potentially generated by proposed cartilage repair strategies must be compared with the spontaneous changes that occur in similarly created untreated lesions. The prevention of the secondary changes in the surrounding cartilage and subchondral bone described in this article should be addressed with the introduction of treatments for repairs of the articulating surface.

  4. Computational biomechanics of articular cartilage of human knee joint: effect of osteochondral defects. (United States)

    Shirazi, R; Shirazi-Adl, A


    Articular cartilage and its supporting bone functional conditions are tightly coupled as injuries of either adversely affects joint mechanical environment. The objective of this study was set to quantitatively investigate the extent of alterations in the mechanical environment of cartilage and knee joint in presence of commonly observed osteochondral defects. An existing validated finite element model of a knee joint was used to construct a refined model of the tibial lateral compartment including proximal tibial bony structures. The response was computed under compression forces up to 2000 N while simulating localized bone damage, cartilage-bone horizontal split, bone overgrowth and absence of deep vertical collagen fibrils. Localized tibial bone damage increased overall joint compliance and substantially altered pattern and magnitude of contact pressures and cartilage strains in both tibia and femur. These alterations were further exacerbated when bone damage was combined with base cartilage split and absence of deep vertical collagen fibrils. Local bone boss markedly changed contact pressures and strain patterns in neighbouring cartilage. Bone bruise/fracture and overgrowth adversely perturbed the homeostatic balance in the mechanical environment of articulate cartilage surrounding and opposing the lesion as well as the joint compliance. As such, they potentially contribute to the initiation and development of post-traumatic osteoarthritis.

  5. Supramolecular Organization of Collagen Fibrils in Healthy and Osteoarthritic Human Knee and Hip Joint Cartilage.

    Directory of Open Access Journals (Sweden)

    Riccardo Gottardi

    Full Text Available Cartilage matrix is a composite of discrete, but interacting suprastructures, i.e. cartilage fibers with microfibrillar or network-like aggregates and penetrating extrafibrillar proteoglycan matrix. The biomechanical function of the proteoglycan matrix and the collagen fibers are to absorb compressive and tensional loads, respectively. Here, we are focusing on the suprastructural organization of collagen fibrils and the degradation process of their hierarchical organized fiber architecture studied at high resolution at the authentic location within cartilage. We present electron micrographs of the collagenous cores of such fibers obtained by an improved protocol for scanning electron microscopy (SEM. Articular cartilages are permeated by small prototypic fibrils with a homogeneous diameter of 18 ± 5 nm that can align in their D-periodic pattern and merge into larger fibers by lateral association. Interestingly, these fibers have tissue-specific organizations in cartilage. They are twisted ropes in superficial regions of knee joints or assemble into parallel aligned cable-like structures in deeper regions of knee joint- or throughout hip joints articular cartilage. These novel observations contribute to an improved understanding of collagen fiber biogenesis, function, and homeostasis in hyaline cartilage.

  6. Tissue engineering of autologous cartilage for craniofacial reconstruction by injection molding. (United States)

    Chang, Sophia C N; Tobias, Geoffrey; Roy, Amit K; Vacanti, Charles A; Bonassar, Lawrence J


    Each year, more than one million patients undergo some type of procedure involving cartilage reconstruction. Polymer hydrogels such as alginate have been demonstrated to be effective carriers of chondrocytes for subcutaneous cartilage formation. The goal of this study was to develop a simple method to create complex structures with good three-dimensional tolerance in order to form cartilage in specific shapes in an autologous animal model. Six alginate implants that had been seeded with autologous chondrocytes through an injection molding process were implanted subcutaneously in sheep, harvested after 6 months, and analyzed histologically, biochemically, and biomechanically, in comparison with original auricular cartilage. Molds of craniofacial implants were prepared with Silastic E RTV (Dow Corning, Midland, Mich.). Chondrocytes were harvested from sheep auricular cartilage and suspended in 2% alginate at a concentration of 50 x 10(6) cells/ml. The mixture of cells and gel was injected into the Silastic molds and removed after 20 minutes. Chondrocyte-alginate constructs were implanted subcutaneously in the necks of the sheep from which the cells had originally been harvested, and the constructs were removed after 30 weeks. Analyses of the implanted constructs indicated cartilage formation with three-dimensional shape retention. The proteoglycan and collagen contents of the constructs increased with time to approximately 80 percent of the values for native tissue. The equilibrium modulus and the hydraulic permeability were 74 and 105 percent of those of native sheep auricular cartilage, respectively.

  7. Microscopically derived potential energy surfaces from mostly structural considerations

    Energy Technology Data Exchange (ETDEWEB)

    Ermamatov, M.J. [Instituto de Física, Universidade Federal Fluminense, 24210-340, Niterói, Rio de Janeiro (Brazil); Institute of Nuclear Physics, Ulughbek, Tashkent 100214 (Uzbekistan); Hess, Peter O., E-mail: [Instituto de Ciencias Nucleares, UNAM, Circuito Exterior, C.U., A.P. 70-543, 04510, Mexico D.F. (Mexico)


    A simple procedure to estimate the quadrupole Potential-Energy-Surface (PES) is presented, using mainly structural information, namely the content of the shell model space and the Pauli exclusion principle. Further microscopic properties are implicitly contained through the use of results from the Möller and Nix tables or experimental information. A mapping to the geometric potential is performed yielding the PES. The General Collective Model is used in order to obtain an estimate on the spectrum and quadrupole transitions, adjusting only the mass parameter. First, we test the conjecture on known nuclei, deriving the PES and compare them to known data. We will see that the PES approximates very well the structure expected. Having acquired a certain confidence, we predict the PES of several chain of isotopes of heavy and super-heavy nuclei and at the end we investigate the structure of nuclei in the supposed island of stability. One of the main points to show is that simple assumptions can provide already important information on the structure of nuclei outside known regions and that spectra and electromagnetic transitions can be estimated without using involved calculations and assumptions. The procedure does not allow to calculate binding energies. The method presented can be viewed as a starting point for further improvements.

  8. Izogenic cartilage transfer in rhinoplasty procedure. (United States)

    Yigit, Baris; Bicer, Ahmet; Aytop, Derya


    Cartilage is commonly grafted during primary and secondary rhinoplasties as a means of addressing both functional and esthetic issues. Generally, such grafts are taken from the nasal septum, but auricular conchae or ribs may serve as donor sites if needed. However, the latter often entail considerable morbidity and graft mismatch. To circumvent these drawbacks, use of implants or processed cartilage (allogenic or xenogenic in origin) has been proposed. Herein, the isogenic transfer of nasal septal cartilage between identical twins is reported.

  9. A high throughput mechanical screening device for cartilage tissue engineering. (United States)

    Mohanraj, Bhavana; Hou, Chieh; Meloni, Gregory R; Cosgrove, Brian D; Dodge, George R; Mauck, Robert L


    Articular cartilage enables efficient and near-frictionless load transmission, but suffers from poor inherent healing capacity. As such, cartilage tissue engineering strategies have focused on mimicking both compositional and mechanical properties of native tissue in order to provide effective repair materials for the treatment of damaged or degenerated joint surfaces. However, given the large number design parameters available (e.g. cell sources, scaffold designs, and growth factors), it is difficult to conduct combinatorial experiments of engineered cartilage. This is particularly exacerbated when mechanical properties are a primary outcome, given the long time required for testing of individual samples. High throughput screening is utilized widely in the pharmaceutical industry to rapidly and cost-effectively assess the effects of thousands of compounds for therapeutic discovery. Here we adapted this approach to develop a high throughput mechanical screening (HTMS) system capable of measuring the mechanical properties of up to 48 materials simultaneously. The HTMS device was validated by testing various biomaterials and engineered cartilage constructs and by comparing the HTMS results to those derived from conventional single sample compression tests. Further evaluation showed that the HTMS system was capable of distinguishing and identifying 'hits', or factors that influence the degree of tissue maturation. Future iterations of this device will focus on reducing data variability, increasing force sensitivity and range, as well as scaling-up to even larger (96-well) formats. This HTMS device provides a novel tool for cartilage tissue engineering, freeing experimental design from the limitations of mechanical testing throughput. © 2013 Published by Elsevier Ltd.

  10. Can Glucosamine Supplements Protect My Knee Cartilage from Osteoarthritis? (United States)

    ... Can glucosamine supplements protect my knee cartilage from osteoarthritis? Answers from Brent A. Bauer, M.D. Study results on this question have ... build cartilage. The most common type of arthritis, osteoarthritis wears away the slick cartilage that covers the ...

  11. X-ray standing wave studies of surface adsorption structures

    CERN Document Server

    Kariapper, M S


    13 deg from the surface normal. The three F atoms appeared to deviate from the gas phase geometry by having an increased F-P-F angle. conclusion confirms the results of a recent near-edge and surface extended x-ray absorption fine structure study, but contrasts with the established adsorbate-induced reconstruction produced by this species on Cu(111). The asymmetry parameter Q arising from dipole-quadrupole interference in core-level photoemission from F 1s and P 1s states at photon energies 3430 eV and 2975 eV have been determined to be 0.31 +- 0.02 and 0.18 +- 0.02, respectively, via NIXSW experiments conducted on multilayer films of perfluorohexane, C sub 6 F sub 1 sub 4 and phosphorous tribromide, PBr sub 3 , grown on Cu(100). The structure of the PF sub 3 molecule adsorbed on Cu(100) (dosed with the crystal kept at around 110 K and then annealed briefly to 180 K) has been studied by P K-edge NEXAFS and NIXSW at both (200) and (111) reflections using absorption at both the P and F atoms of the adsorbate mo...

  12. Surface plasmon interference lithography using Al grating structure on glass (United States)

    Kim, Yong Min; Choi, Kyung Cheol


    Photolithography is used in the important technologies of the device fabrication process in the semiconductor industry. However, photolithography has a pattern resolution limit because of the diffraction of light. Using surface plasmon (SP) is one of the ways to overcome this limit, which is a recently proposed nanolithography technology. Using SP, we developed a fabrication process using an Al grating structure on glass (glass/Al grating/PR structure). A perfect contact between the photoresist and the Al grating increased the effects of the SP because the contact gap was reduced in the photolithography process. The pattern pitch of lithography result was 120 nm (simulation results) and 115 nm (fabrication results). In surface plasmon interference lithography (SPIL) it is possible to use SP in the photolithography area. And we analyzed irregular pattern trends in the shape of random horizontal patterns and found that the patterns result from Al line edge roughness. Therefore, techniques that reduce the Al line edge roughness could enable clearer Al line patterns in SPIL.

  13. MRI of Native Knee Cartilage Delamination Injuries. (United States)

    White, Candace L; Chauvin, Nancy A; Waryasz, Gregory R; March, Bradford T; Francavilla, Michael L


    The purpose of this article is to describe the normal imaging appearance of cartilage and the pathophysiologic findings, imaging appearance, and surgical management of cartilage delamination. Delamination injuries of knee cartilage signify surgical lesions that can lead to significant morbidity without treatment. These injuries may present with clinical symptoms identical to those associated with meniscal injury, and arthroscopic identification can be difficult, thereby creating a role for imaging diagnosis. A low sensitivity of imaging identification of delamination injury of the knee is reported in the available literature, although vast improvements in MRI of cartilage have since been introduced.

  14. Cartilage thickness measurements from optical coherence tomography (United States)

    Rogowska, Jadwiga; Bryant, Clifford M.; Brezinski, Mark E.


    We describe a new semiautomatic image processing method for detecting the cartilage boundaries in optical coherence tomography (OCT). In particular, we focus on rabbit cartilage since this is an important animal model for testing both chondroprotective agents and cartilage repair techniques. The novel boundary-detection system presented here consists of (1) an adaptive filtering technique for image enhancement and speckle reduction, (2) edge detection, and (3) edge linking by graph searching. The procedure requires several steps and can be automated. The quantitative measurements of cartilage thickness on OCT images correlated well with measurements from histology.

  15. Cellular and Acellular Approaches for Cartilage Repair (United States)


    There are several choices of cells to use for cartilage repair. Cells are used as internal or external sources and sometimes in combination. In this article, an analysis of the different cell choices and their use and potential is provided. Embryonic cartilage formation is of importance when finding more about how to be able to perfect cartilage repair. Some suggestions for near future research based on up-to-date knowledge on chondrogenic cells are given to hopefully stimulate more studies on the final goal of cartilage regeneration. PMID:27340516

  16. Hyaluronan protects against cartilage damage by decreasing stiffness and changing3-D microarchitecture of subchondral bone in guinea pig primary osteoarthrosis

    DEFF Research Database (Denmark)

    Ding, Ming

    volume fraction, and surface density. In the long-term study, both HA groups had greater volume fraction and cortical thickness. HA groups had greater bone mineral concentration and mineral density, lower collagen to mineral ratio, and preserved the mechanical properties of cancellous bone. The effects...... of HA on cartilage and subchondral bone were maintained when HA treatment was discontinued (Table 1).   Discussion: The current study has investigated the effects of HA on the properties of subchondral bone tissues in a primary guinea pig OA model. Significant positive effects of high molecular weight...... of cancellous bone. The most striking features are the microarchitectural changes in the subchondral cancellous bone that lead to lower bone density and markedly rod-like structure, and thus reducing cartilage stress during impact loading. Still, the subchondral bone has a greater mineral concentration...

  17. The effect of sodium hyaluronate–chondroitin sulfate combined solution on cartilage formation in osteochondral defects of the rabbit knee: an experimental study (United States)

    Tosun, Haci Bayram; Gürger, Murat; Gümüştaş, Seyit Ali; Uludag, Abuzer; Üçer, Özlem; Serbest, Sancar; Çelik, Suat


    Objective In focal cartilage lesions, multipotent mesenchymal stem cells in bone marrow are aimed to be moved into the defect area using subchondral drilling or microfracture method. However, repaired tissue insufficiently fills the defect area or cannot meet natural hyaline tissue functions, due to fibrous structure. We investigated the effect of a combined solution of sodium hyaluronate + chondroitin sulfate (HA+CS) administered intra-articularly after subchondral drilling on newly formed cartilage in rabbits with focal osteochondral defects. Materials and methods A total of 32 New Zealand White mature rabbits, whose weights ranged from 2.5 to 3 kg, were randomly divided into four groups. Full-thickness osteochondral defect was formed in the left-knee medial femur condyles of all rabbits. Subchondral drilling was then performed. The following treatment protocol was administered intra-articularly on knee joints on days 7, 14, and 21 after surgery: group 1, 0.3 mL combined solution of HA+CS (20 mg CS combined with 16 mg HA/mL); group 2, 0.3 mL HA (16 mg/mL); group 3, 0.3 mL CS (20 mg/mL); and group 4 (control group), 0.3 mL saline solution. In the sixth week, all animals were killed and then evaluated histopathologically and biochemically. Results There was significant articular cartilage formation in the HA+CS group compared to the HA, CS, and control groups. Hyaline cartilage formation was observed only in the HA+CS group. Cartilage-surface continuity and smoothness were significantly higher in the HA+CS and HA groups compared to the other groups. Normal cartilage mineralization was found to be significantly higher in the HA+CS group compared to the other groups. Increased levels of VEGFA and IL-1β in synovial fluid were observed in the HA+CS group. Conclusion After subchondral drilling, intra-articular HA-CS combination therapy is a good choice to promote better quality new cartilage-tissue formation in the treatment of focal osteochondral defects. PMID

  18. The effect of sodium hyaluronate-chondroitin sulfate combined solution on cartilage formation in osteochondral defects of the rabbit knee: an experimental study. (United States)

    Tosun, Haci Bayram; Gürger, Murat; Gümüştaş, Seyit Ali; Uludag, Abuzer; Üçer, Özlem; Serbest, Sancar; Çelik, Suat


    In focal cartilage lesions, multipotent mesenchymal stem cells in bone marrow are aimed to be moved into the defect area using subchondral drilling or microfracture method. However, repaired tissue insufficiently fills the defect area or cannot meet natural hyaline tissue functions, due to fibrous structure. We investigated the effect of a combined solution of sodium hyaluronate + chondroitin sulfate (HA+CS) administered intra-articularly after subchondral drilling on newly formed cartilage in rabbits with focal osteochondral defects. A total of 32 New Zealand White mature rabbits, whose weights ranged from 2.5 to 3 kg, were randomly divided into four groups. Full-thickness osteochondral defect was formed in the left-knee medial femur condyles of all rabbits. Subchondral drilling was then performed. The following treatment protocol was administered intra-articularly on knee joints on days 7, 14, and 21 after surgery: group 1, 0.3 mL combined solution of HA+CS (20 mg CS combined with 16 mg HA/mL); group 2, 0.3 mL HA (16 mg/mL); group 3, 0.3 mL CS (20 mg/mL); and group 4 (control group), 0.3 mL saline solution. In the sixth week, all animals were killed and then evaluated histopathologically and biochemically. There was significant articular cartilage formation in the HA+CS group compared to the HA, CS, and control groups. Hyaline cartilage formation was observed only in the HA+CS group. Cartilage-surface continuity and smoothness were significantly higher in the HA+CS and HA groups compared to the other groups. Normal cartilage mineralization was found to be significantly higher in the HA+CS group compared to the other groups. Increased levels of VEGFA and IL-1β in synovial fluid were observed in the HA+CS group. After subchondral drilling, intra-articular HA-CS combination therapy is a good choice to promote better quality new cartilage-tissue formation in the treatment of focal osteochondral defects.

  19. In situ friction measurement on murine cartilage by atomic force microscopy. (United States)

    Coles, Jeffrey M; Blum, Jason J; Jay, Gregory D; Darling, Eric M; Guilak, Farshid; Zauscher, Stefan


    Articular cartilage provides a low-friction, wear-resistant surface for the motion of diarthrodial joints. The objective of this study was to develop a method for in situ friction measurement of murine cartilage using a colloidal probe attached to the cantilever of an atomic force microscope. Sliding friction was measured between a chemically functionalized microsphere and the cartilage of the murine femoral head. Friction was measured at normal loads ranging incrementally from 20 to 100 nN with a sliding speed of 40 microm/s and sliding distance of 64 microm. Under these test conditions, hydrostatic pressurization and biphasic load support in the cartilage were minimized, providing frictional measurements that predominantly reflect boundary lubrication properties. Friction coefficients measured on murine tissue (0.25+/-0.11) were similar to those measured on porcine tissue (0.23+/-0.09) and were in general agreement with measurements of boundary friction on cartilage by other researchers. Using the colloidal probe as an indenter, the elastic mechanical properties and surface roughness were measured in the same configuration. Interfacial shear was found to be the principal mechanism of friction generation, with little to no friction resulting from plowing forces, collision forces, or energy losses due to normal deformation. This measurement technique can be applied to future studies of cartilage friction and mechanical properties on genetically altered mice or other small animals.

  20. SOX trio decrease in the articular cartilage with the advancement of osteoarthritis. (United States)

    Lee, Jai-Sun; Im, Gun-Il


    SOX trio (SOX-5, SOX-6, and SOX-9) maintain the chondrocytic phenotypes and are vital for chondrogenesis in embryonic development. The purpose of this study is to investigate the change in the expression of SOX trio with the advancement of osteoarthritis (OA) in human articular cartilage (AC). Human OA samples from eight patients were obtained from the distal femoral condyles during total knee arthroplasty. Minimally OA cartilage taken from areas with no obvious surface defects on lateral condyles was compared with advanced OA cartilage obtained from areas within 1 cm of overt lesion located on medial condyle surface. SOX-5, SOX-6, and SOX-9 gene expressions significantly decreased by 41% (p = 0.047), 46% (p = 0.047), and 56% (p = 0.029) in advanced OA area compared with the minimally OA area. There was a significant decrease in aggrecan and type II collagen (COL2A1) gene expressions by 73% (p = 0.029) and 65% (p = 0.029), respectively, in advanced OA area compared with the minimally OA area. From Western blotting and immunohistochemistry, SOX-5, SOX-6, SOX-9, type II collagen, and aggrecan protein expressions also significantly decreased in advanced OA cartilage compared with minimally OA cartilage. DNA methylation study of SOX-9 promoter regions revealed no difference in the epigenetic status between the two areas. It is concluded that SOX trio gene and protein decreased with advancement of OA in human articular cartilage.

  1. Novel Genetic Variants for Cartilage Thickness and Hip Osteoarthritis.

    Directory of Open Access Journals (Sweden)

    Martha C Castaño-Betancourt


    Full Text Available Osteoarthritis is one of the most frequent and disabling diseases of the elderly. Only few genetic variants have been identified for osteoarthritis, which is partly due to large phenotype heterogeneity. To reduce heterogeneity, we here examined cartilage thickness, one of the structural components of joint health. We conducted a genome-wide association study of minimal joint space width (mJSW, a proxy for cartilage thickness, in a discovery set of 13,013 participants from five different cohorts and replication in 8,227 individuals from seven independent cohorts. We identified five genome-wide significant (GWS, P≤5·0×10-8 SNPs annotated to four distinct loci. In addition, we found two additional loci that were significantly replicated, but results of combined meta-analysis fell just below the genome wide significance threshold. The four novel associated genetic loci were located in/near TGFA (rs2862851, PIK3R1 (rs10471753, SLBP/FGFR3 (rs2236995, and TREH/DDX6 (rs496547, while the other two (DOT1L and SUPT3H/RUNX2 were previously identified. A systematic prioritization for underlying causal genes was performed using diverse lines of evidence. Exome sequencing data (n = 2,050 individuals indicated that there were no rare exonic variants that could explain the identified associations. In addition, TGFA, FGFR3 and PIK3R1 were differentially expressed in OA cartilage lesions versus non-lesioned cartilage in the same individuals. In conclusion, we identified four novel loci (TGFA, PIK3R1, FGFR3 and TREH and confirmed two loci known to be associated with cartilage thickness.The identified associations were not caused by rare exonic variants. This is the first report linking TGFA to human OA, which may serve as a new target for future therapies.

  2. Novel Genetic Variants for Cartilage Thickness and Hip Osteoarthritis (United States)

    Metrustry, Sarah; Liu, Youfang; den Hollander, Wouter; Kraus, Virginia B.; Yau, Michelle S.; Mitchell, Braxton D.; Muir, Kenneth; Hofman, Albert; Doherty, Michael; Doherty, Sally; Zhang, Weiya; Kraaij, Robert; Rivadeneira, Fernando; Barrett-Connor, Elizabeth; Maciewicz, Rose A.; Arden, Nigel; Nelissen, Rob G. H. H.; Kloppenburg, Margreet; Jordan, Joanne M.; Nevitt, Michael C.; Slagboom, Eline P.; Hart, Deborah J.; Lafeber, Floris; Styrkarsdottir, Unnur; Zeggini, Eleftheria; Evangelou, Evangelos; Spector, Tim D.; Uitterlinden, Andre G.; Lane, Nancy E.; Meulenbelt, Ingrid; Valdes, Ana M.; van Meurs, Joyce B. J.


    Osteoarthritis is one of the most frequent and disabling diseases of the elderly. Only few genetic variants have been identified for osteoarthritis, which is partly due to large phenotype heterogeneity. To reduce heterogeneity, we here examined cartilage thickness, one of the structural components of joint health. We conducted a genome-wide association study of minimal joint space width (mJSW), a proxy for cartilage thickness, in a discovery set of 13,013 participants from five different cohorts and replication in 8,227 individuals from seven independent cohorts. We identified five genome-wide significant (GWS, P≤5·0×10−8) SNPs annotated to four distinct loci. In addition, we found two additional loci that were significantly replicated, but results of combined meta-analysis fell just below the genome wide significance threshold. The four novel associated genetic loci were located in/near TGFA (rs2862851), PIK3R1 (rs10471753), SLBP/FGFR3 (rs2236995), and TREH/DDX6 (rs496547), while the other two (DOT1L and SUPT3H/RUNX2) were previously identified. A systematic prioritization for underlying causal genes was performed using diverse lines of evidence. Exome sequencing data (n = 2,050 individuals) indicated that there were no rare exonic variants that could explain the identified associations. In addition, TGFA, FGFR3 and PIK3R1 were differentially expressed in OA cartilage lesions versus non-lesioned cartilage in the same individuals. In conclusion, we identified four novel loci (TGFA, PIK3R1, FGFR3 and TREH) and confirmed two loci known to be associated with cartilage thickness.The identified associations were not caused by rare exonic variants. This is the first report linking TGFA to human OA, which may serve as a new target for future therapies. PMID:27701424

  3. Chondrocalcinosis of the hyaline cartilage of the knee: MRI manifestations

    Energy Technology Data Exchange (ETDEWEB)

    Beltran, J.; Marty-Delfaut, E.; Bencardino, J.; Rosenberg, Z.S. [Department of Radiology, Hospital for Joint Diseases, New York, NY (United States); Steiner, G. [Department of Pathology, Hospital for Joint Diseases, New York, NY (United States); Aparisi, F. [Department of Radiology, Residencia Sanitaria ``La Fe``, Valencia (Spain); Padron, M. [Clinica San Camilo, Madrid (Spain)


    Purpose. To determine the ability of MRI to detect the presence of crystals of calcium pyrophosphate in the articular cartilage of the knee. Design and patients. The MR studies of 12 knees (11 cases) were reviewed retrospectively and correlated with radiographs (12 cases) and the findings at arthroscopy (2 cases) and surgery (1 case). A total of 72 articular surfaces were evaluated. Radiographic, surgical or arthroscopic demonstration of chondrocalcinosis was used as the gold standard. Additionally, two fragments of the knee of a patient who underwent total knee replacement and demonstrated extensive chondrocalcinosis were studied with radiography and MRI using spin-echo T1-, T2- and proton-density-weighted images as well as two- and three-dimensional fat saturation (2D and 3D Fat Sat) gradient recalled echo (GRE) and STIR sequences. Results. MRI revealed multiple hypointense foci within the articular cartilage in 34 articular surfaces, better shown on 2D and 3D GRE sequences. Radiographs showed 12 articular surfaces with chondrocalcinosis. In three cases with arthroscopic or surgical correlation, MRI demonstrated more diffuse involvement of the articular cartilage than did the radiographs. The 3D Fat Sat GRE sequences were the best for demonstrating articular calcification in vitro. In no case was meniscal calcification identified with MRI. Hyperintense halos around some of the calcifications were seen on the MR images. Conclusion. MRI can depict articular cartilage calcification as hypointense foci using GRE techniques. Differential diagnosis includes loose bodies, post-surgical changes, marginal osteophytes and hemosiderin deposition. (orig.) With 4 figs., 14 refs.

  4. Genipin crosslinking decreases the mechanical wear and biochemical degradation of impacted cartilage in vitro. (United States)

    Bonitsky, Craig M; McGann, Megan E; Selep, Michael J; Ovaert, Timothy C; Trippel, Stephen B; Wagner, Diane R


    High energy trauma to cartilage causes surface fissures and microstructural damage, but the degree to which this damage renders the tissue more susceptible to wear and contributes to the progression of post-traumatic osteoarthritis (PTOA) is unknown. Additionally, no treatments are currently available to strengthen cartilage after joint trauma and to protect the tissue from subsequent degradation and wear. The purposes of this study were to investigate the role of mechanical damage in the degradation and wear of cartilage, to evaluate the effects of impact and subsequent genipin crosslinking on the changes in the viscoelastic parameters of articular cartilage, and to test the hypothesis that genipin crosslinking is an effective treatment to enhance the resistance to biochemical degradation and mechanical wear. Results demonstrate that cartilage stiffness decreases after impact loading, likely due to the formation of fissures and microarchitectural damage, and is partially or fully restored by crosslinking. The wear resistance of impacted articular cartilage was diminished compared to undamaged cartilage, suggesting that mechanical damage that is directly induced by the impact may contribute to the progression of PTOA. However, the decrease in wear resistance was completely reversed by the crosslinking treatments. Additionally, the crosslinking treatments improved the resistance to collagenase digestion at the impact-damaged articular surface. These results highlight the potential therapeutic value of collagen crosslinking via genipin in the prevention of cartilage degeneration after traumatic injury. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:558-565, 2017. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  5. Technical Report: Correlation Between the Repair of Cartilage and Subchondral Bone in an Osteochondral Defect Using Bilayered, Biodegradable Hydrogel Composites. (United States)

    Lu, Steven; Lam, Johnny; Trachtenberg, Jordan E; Lee, Esther J; Seyednejad, Hajar; van den Beucken, Jeroen J J P; Tabata, Yasuhiko; Kasper, F Kurtis; Scott, David W; Wong, Mark E; Jansen, John A; Mikos, Antonios G


    The present work investigated correlations between cartilage and subchondral bone repair, facilitated by a growth factor-delivering scaffold, in a rabbit osteochondral defect model. Histological scoring indices and microcomputed tomography morphological parameters were used to evaluate cartilage and bone repair, respectively, at 6 and 12 weeks. Correlation analysis revealed significant associations between specific cartilage indices and subchondral bone parameters that varied with location in the defect (cortical vs. trabecular region), time point (6 vs. 12 weeks), and experimental group (insulin-like growth factor-1 only, bone morphogenetic protein-2 only, or both growth factors). In particular, significant correlations consistently existed between cartilage surface regularity and bone quantity parameters. Overall, correlation analysis between cartilage and bone repair provided a fuller understanding of osteochondral repair and can help drive informed studies for future osteochondral regeneration strategies.

  6. A new nose tip-defining technique for Asians using autologous cartilage prefabricated with octyl-2-cyanoacrylate adhesive. (United States)

    Seo, Jeong-Ok; Kwon, Jang-Woo; Kim, Sung-Kyun; Lim, Joo-Sin; Park, Dong-Joon


    To form and test a prefabricated, 3-dimensional tip graft structure from autologous cartilage pieces and octyl-2-cyanoacrylate adhesive (Dermabond). Displacement and instability of grafted cartilage are common drawbacks of endonasal tip surgery, and we evaluated the feasibility and efficacy of octyl-2-cyanoacrylate adhesive for clinical use. Three New Zealand rabbits were examined in this study. We cut auricular cartilage into pieces of approximately 1 x 2 cm and glued them together with octyl-2-cyanoacrylate. Three months after subcutaneous implantation in the rabbits, we histopathologically analyzed foreign body reactions, histotoxic effects, and the structure of the regenerative tissue in the implanted cartilage. Furthermore, from human patients we harvested small pieces of autologous cartilage and cemented them together with octyl-2-cyanoacrylate adhesive to prefabricate 3-dimensional tip grafts, which we then inserted into the nasal tips of patients via an endonasal approach to project and contour the nasal tip. The changes in tip definition of 42 Asian patients were analyzed. Octyl-2-cyanoacrylate adhesive interacts well with cartilage tissues with no systemic or local adverse effects. Its ability to bond cartilage instantaneously allows for the fabrication of intricate cartilage implant components. The aesthetic results in 42 cases were excellent, and the implants were both safe and effective. Our results demonstrate that octyl-2-cyanoacrylate can be safely used in endonasal tip surgery to produce excellent cosmetic outcomes in Asian subjects.

  7. Predicting knee cartilage loss using adaptive partitioning of cartilage thickness maps

    DEFF Research Database (Denmark)

    Jørgensen, Dan Richter; Dam, Erik B.; Lillholm, Martin


    This study investigates whether measures of knee cartilage thickness can predict future loss of knee cartilage. A slow and a rapid progressor group was determined using longitudinal data, and anatomically aligned cartilage thickness maps were extracted from MRI at baseline. A novel machine learning...... framework was then trained using these maps. Compared to measures of mean cartilage plate thickness, group separation was increased by focusing on local cartilage differences. This result is central for clinical trials where inclusion of rapid progressors may help reduce the period needed to study effects...

  8. Electronic structure of benzene adsorbed on Ni and Cu surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Weinelt, M.; Nilsson, A.; Wassdahl, N. [Uppsala Univ. (Sweden)] [and others


    Benzene has for a long time served as a prototype adsorption system of large molecules. It adsorbs with the molecular plane parallel to the surface. The bonding of benzene to a transition metal is typically viewed to involve the {pi} system. Benzene adsorbs weakly on Cu and strongly on Ni. It is interesting to study how the adsorption strength is reflected in the electronic structure of the adsorbate-substrate complex. The authors have used X-ray Emission (XE) and X-ray Absorption (XA) spectroscopies to selectively study the electronic states localized on the adsorbed benzene molecule. Using XES the occupied states can be studies and with XAS the unoccupied states. The authors have used beamline 8.0 and the Swedish endstation equipped with a grazing incidence x-ray spectrometer and a partial yield absorption detector. The resolution in the XES and XAS were 0.5 eV and 0.05 eV, respectively.

  9. Formation and structure of surface films: captive bubble surfactometry. (United States)

    Schürch, S; Green, F H; Bachofen, H


    transmission electron microscopy, the surface film frequently appears multilaminated, not only in the alveolar corners or crevices, but also at the thin air-blood barrier above the capillaries. Disk-like structures or multilamellar vesicles appear partially integrated into the planar multilayered film. In corners and crevices, tubular myelin appears closely associated with the surface film. Tubular myelin, however, is not necessary for the generation of a multilaminated film. This is demonstrated in vitro by the fixation for electron microscopy of a film formed from lipid extract surfactant on a captive bubble. Films formed from relatively high surfactant concentration (1 mg/ml of phospholipid) are of variable thickness and frequent multilayers are seen. In contrast, at 0.3 mg/ml, only an amorphous film can be visualized. Although near zero minimum surface tensions can be obtained for both surfactant concentrations, film compressibility and mechanical stability are substantially better at the higher concentrations. This appears to be related to the multilaminated structure of the film formed at the higher concentration.

  10. Influence of Proteoglycan on Time-Dependent Mechanical Behaviors of Articular Cartilage under Constant Total Compressive Deformation (United States)

    Murakami, Teruo; Sakai, Nobuo; Sawae, Yoshinori; Tanaka, Koji; Ihara, Maki

    Articular cartilage has biphasic property based on high water content. It is generally believed that the proteoglycan supports the compressive load, but the detailed loading mechanism has not yet been clarified. In this study, first we observed the changes in compressive stress and strain of articular cartilage under constant total compressive deflection. We evaluated the changes in modulus of elasticity, which was estimated from the stress-strain relation in equilibrium state. To examine the role of proteoglycan in compressed articular cartilage, we compared the time-dependent viscoelastic behaviors in both the intact cartilage and the cartilage treated with chondoroitinase ABC under constant total compressive deformation. We could confirm that the peak stress after compression and the modulus of elasticity at equilibrium were reduced after the digestion of proteoglycan. Next, we observed the changes in local strain in both articular cartilage specimens with and without chondroitinase treatment by monitoring the position of stained chondrocyte in the confocal laser scanning microscope. These visualized images indicated that the local strain changed time-dependently and depth-dependently. The digested cartilage showed the quicker change in movement and larger thinning in surface layer than the intact cartilage. These results indicate that the proteoglycan contributes to the compressive load-carrying capacity and controls the permeability.

  11. Oxalate oxidases and differentiating surface structure in wheat: germins. (United States)

    Lane, B G


    Oxalate oxidases (OXOs) have been found to be concentrated in the surface tissues of wheat embryos and grains: germin is concentrated in root and leaf sheaths that surround germinated embryos; pseudogermin (OXO-psi) is concentrated in the epidermis and bracts that 'encircle' mature grains. Most strikingly, the epidermal accumulation of OXO-psi was found to presage the transition of a delicate 'skin', similar to the fragile epidermis of human skin, into the tough shell (the miller's 'beeswing') that is typical of mature wheat grains. A narrow range of oxalate concentration (1--2 mM) in the hydrated tissues of major crop cereals (barley, maize, oat, rice, rye and wheat) contrasted with wide variations in their OXO expression, e.g. cold-tolerant and cold-sensitive varieties of maize have similar oxalate contents but the former was found to contain approx. 20-fold more germin than did the latter. Well-known OXOs in sorghum, a minor cereal, and beet, a dicotyledon, were found to have little antigenic relatedness to the germins, but the beet enzyme did share some of the unique stability properties that are peculiar to the germin-like OXOs that are found only in the major crop cereals. Their concentration in surface structures of domesticated wheat suggests a biochemical role for germin-like OXOs: programmed cell death in surface tissues might be a constitutive as well as an adaptive form of differentiation that helps to produce refractory barriers against tissue invasion by predators. Incidental to the principal investigation, and using an OXO assay (oxalate-dependent release of CO(2)) that did not rely on detecting H(2)O(2), which is often fully degraded in cell extracts, it was found that OXO activity in soluble extracts of wheat was manifested only in standard solution assays if the extract was pretreated in a variety of ways, which included preincubation with pepsin or highly substituted glucuronogalactoarabinoxylans (cell-wall polysaccharides).

  12. Andrew Liehr and the structure of Jahn-Teller surfaces (United States)

    Chibotaru, Liviu F.; Iwahara, Naoya


    The present article is an attempt to draw attention to a seminal work by Andrew Liehr “Topological aspects of conformational stability problem” [1, 2] issued more than half century ago. The importance of this work stems from two aspects of static Jahn-Teller and pseudo-Jahn-Teller problems fully developed by the author. First, the work of Liehr offers an almost complete overview of adiabatic potential energy surfaces for most known Jahn-Teller problems including linear, quadratic and higher-order vibronic couplings. Second, and most importantly, it identifies the factors defining the structure of Jahn-Teller surfaces. Among them, one should specially mention the minimax principle stating that the distorted Jahn-Teller systems tend to preserve the highest symmetry consistent with the loss of their orbital degeneracy. We believe that the present short reminiscence not only will introduce a key Jahn-Teller scientist to the young members of the community but also will serve as a vivid example of how a complete understanding of a complex problem, which the Jahn-Teller effect certainly was in the beginning of 1960s, can be achieved.

  13. Micropatterned Azopolymer Surfaces Modulate Cell Mechanics and Cytoskeleton Structure. (United States)

    Rianna, Carmela; Ventre, Maurizio; Cavalli, Silvia; Radmacher, Manfred; Netti, Paolo A


    Physical and chemical characteristics of materials are important regulators of cell behavior. In particular, cell elasticity is a fundamental parameter that reflects the state of a cell. Surface topography finely modulates cell fate and function via adhesion mediated signaling and cytoskeleton generated forces. However, how topographies alter cell mechanics is still unclear. In this work we have analyzed the mechanical properties of peripheral and nuclear regions of NIH-3T3 cells on azopolymer substrates with different topographic patterns. Micrometer scale patterns in the form of parallel ridges or square lattices of surface elevations were encoded on light responsive azopolymer films by means of contactless optical methods. Cell mechanics was investigated by atomic force microscopy (AFM). Cells and consequently the cell cytoskeleton were oriented along the linear patterns affecting cytoskeletal structures, e.g., formation of actin stress fibers. Our data demonstrate that topographic substrate patterns are recognized by cells and mechanical information is transferred by the cytoskeleton. Furthermore, cytoskeleton generated forces deform the nucleus, changing its morphology that appears to be related to different mechanical properties in the nuclear region.

  14. Femtosecond laser surface structuring of molybdenum thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kotsedi, L., E-mail: [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); Mthunzi, P. [Council for Scientific and Industrial Research (CSIR), Biophotonics Lab: National Laser Centre Pretoria, 0001 (South Africa); Nuru, Z.Y. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); Eaton, S.M. [Physics Department, Politecnico di Milano, Piazza Leonardo Da Vinci, 32, 20133 Milano (Italy); Center for Nano Science and Technology, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Itala (Italy); Sechoghela, P.; Mongwaketsi, N. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); Ramponi, R. [Institute for Photonics and Nanotechnologies (IFN)–CNR, Piazza Leanardo Da Vinci, 32, 20133 Milano (Italy); Maaza, M. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape Province (South Africa)


    Highlights: • Color change of the molybdenum thin film from shinny to violet–yellowish color after laser irradiation at various laser powers. • Formation of the molybdenum dioxide coating after laser exposure, as confirmed by the X-ray diffraction spectrometry. • Selective solar absorbing nature of the laser exposed films. • Study of the binding energies is presented in this contribution using the XPS spectrometry. - Abstract: This contribution reports on the femtosecond surface structuring of molybdenum thin coatings deposited by electron beam evaporation onto Corning glass substrates. The 1-D type periodic grating lines created by such an ablation showed that the widths of the shallow grooves followed a logarithmic dependence with the laser energy incident on the molybdenum film. The electronic valence “x” of the created oxide surface layer MoO{sub x} was found to be incident laser power dependent via Rutherford backscattering spectrometry, X-ray photoelectron spectroscopy and X-ray diffraction investigations. Such a photo-induced MoO{sub x}–Mo nanocomposite exhibited effective selective solar absorption in the UV–vis–IR spectral range.

  15. Changes in the Chondrocyte and Extracellular Matrix Proteome during Post-natal Mouse Cartilage Development* (United States)

    Wilson, Richard; Norris, Emma L.; Brachvogel, Bent; Angelucci, Constanza; Zivkovic, Snezana; Gordon, Lavinia; Bernardo, Bianca C.; Stermann, Jacek; Sekiguchi, Kiyotoshi; Gorman, Jeffrey J.; Bateman, John F.


    Skeletal growth by endochondral ossification involves tightly coordinated chondrocyte differentiation that creates reserve, proliferating, prehypertrophic, and hypertrophic cartilage zones in the growth plate. Many human skeletal disorders result from mutations in cartilage extracellular matrix (ECM) components that compromise both ECM architecture and chondrocyte function. Understanding normal cartilage development, composition, and structure is therefore vital to unravel these disease mechanisms. To study this intricate process in vivo by proteomics, we analyzed mouse femoral head cartilage at developmental stages enriched in either immature chondrocytes or maturing/hypertrophic chondrocytes (post-natal days 3 and 21, respectively). Using LTQ-Orbitrap tandem mass spectrometry, we identified 703 cartilage proteins. Differentially abundant proteins (q cartilage development (tenascin X, vitrin, Urb, emilin-1, and the sushi repeat-containing proteins SRPX and SRPX2). Meta-analysis of cartilage development in vivo and an in vitro chondrocyte culture model (Wilson, R., Diseberg, A. F., Gordon, L., Zivkovic, S., Tatarczuch, L., Mackie, E. J., Gorman, J. J., and Bateman, J. F. (2010) Comprehensive profiling of cartilage extracellular matrix formation and maturation using sequential extraction and label-free quantitative proteomics. Mol. Cell. Proteomics 9, 1296–1313) identified components involved in both systems, such as Urb, and components with specific roles in vivo, including vitrin and CILP-2 (cartilage intermediate layer protein-2). Immunolocalization of Urb, vitrin, and CILP-2 indicated specific roles at different maturation stages. In addition to ECM-related changes, we provide the first biochemical evidence of changing endoplasmic reticulum function during cartilage development. Although the multifunctional chaperone BiP was not differentially expressed, enzymes and chaperones required specifically for collagen biosynthesis, such as the prolyl 3-hydroxylase 1

  16. Quantitative characterization of articular cartilage using Mueller matrix imaging and multiphoton microscopy. (United States)

    Ellingsen, Pål Gunnar; Lilledahl, Magnus Borstad; Aas, Lars Martin Sandvik; Davies, Catharina de Lange; Kildemo, Morten


    The collagen meshwork in articular cartilage of chicken knee is characterized using Mueller matrix imaging and multiphoton microscopy. Direction and degree of dispersion of the collagen fibers in the superficial layer are found using a Fourier transform image-analysis technique of the second-harmonic generated image. Mueller matrix images are used to acquire structural data from the intermediate layer of articular cartilage where the collagen fibers are too small to be resolved by optical microscopy, providing a powerful multimodal measurement technique. Furthermore, we show that Mueller matrix imaging provides more information about the tissue compared to standard polarization microscopy. The combination of these techniques can find use in improved diagnosis of diseases in articular cartilage, improved histopathology, and additional information for accurate biomechanical modeling of cartilage.

  17. Investigation of polarization-sensitive optical coherence tomography towards the study of microstructure of articular cartilage (United States)

    Kasaragod, Deepa; Lu, Zenghai; Le Maitre, Christine; Wilkinson, J. Mark; Matcher, Stephen


    This paper highlights the extended Jones matrix calculus based multi-angle study carried out to understand the depth dependent structural orientation of the collagen fibers in articular cartilage using polarization-sensitive optical coherence tomography (PS-OCT). A 3D lamellar model for the collagen fiber orientation, with a quadratic profile for the arching of the collagen fibers in transitional zone which points towards an ordered arrangement of fibers in that zone is the basis of the organization architecture of collagen fibers in articular cartilage. Experimental data for both ex-vivo bovine fetlock and human patellar cartilage samples are compared with theoretical predictions, with a good quantitative agreement for bovine and a reasonable qualitative agreement for human articular cartilage samples being obtained

  18. Injectable hydrogels for cartilage tissue engineering

    NARCIS (Netherlands)

    Jin, R.


    Tissue engineering is a promising method for the regeneration of cartilage defects. This approach generally involves the use of a three-dimensional scaffold which can act as a temporary artificial extracellular matrix (ECM) for healthy cartilage cells, chondrocytes. Hydrogels represent a class of

  19. Secondary Impacts on Structures on the Lunar Surface (United States)

    Christiansen, Eric; Walker, James D.; Grosch, Donald J.


    The Altair Lunar Lander is being designed for the planned return to the Moon by 2020. Since it is hoped that lander components will be re-used by later missions, studies are underway to examine the exposure threat to the lander sitting on the Lunar surface for extended periods. These threats involve both direct strikes of meteoroids on the vehicle as well as strikes from Lunar regolith and rock thrown by nearby meteorite strikes. Currently, the lander design is comprised of up to 10 different types of pressure vessels. These vessels included the manned habitation module, fuel, cryogenic fuel and gas storage containers, and instrument bays. These pressure vessels have various wall designs, including various aluminum alloys, honeycomb, and carbon-fiber composite materials. For some of the vessels, shielding is being considered. This program involved the test and analysis of six pressure vessel designs, one of which included a Whipple bumper shield. In addition to the pressure vessel walls, all the pressure vessels are wrapped in multi-layer insulation (MLI). Two variants were tested without the MLI to better understand the role of the MLI in the impact performance. The tests of performed were to examine the secondary impacts on these structures as they rested on the Lunar surface. If a hypervelocity meteor were to strike the surface nearby, it would throw regolith and rock debris into the structure at a much lower velocity. Also, when the manned module departs for the return to Earth, its rocket engines throw up debris that can impact the remaining lander components and cause damage. Glass spheres were used as a stimulant for the regolith material. Impact tests were performed with a gas gun to find the V50 of various sized spheres striking the pressure vessels. The impacts were then modeled and a fast-running approximate model for the V50 data was developed. This model was for performing risk analysis to assist in the vessel design and in the identification of ideal

  20. Cherenkov emission of terahertz surface plasmon polaritons from a superluminal optical spot on a structured metal surface. (United States)

    Bakunov, M I; Tsarev, M V; Hangyo, M


    We propose to launch terahertz surface plasmon polaritons on a structured metal surface by using a femtosecond laser pulse obliquely incident on a strip of an electro-optic material deposited on the surface. The laser pulse creates a nonlinear polarization that moves along the strip with a superluminal velocity and emits surface terahertz waves via the Cherenkov radiation mechanism. We calculate the radiated fields and frequency distribution of the radiated energy for a grooved perfect-conductor surface with a GaAs strip illuminated by Ti:sapphire laser. This technique can be used to perform surface terahertz spectroscopy.

  1. The interior structure of Ceres as revealed by surface topography (United States)

    Fu, Roger R.; Ermakov, Anton I.; Marchi, Simone; Castillo-Rogez, Julie C.; Raymond, Carol A.; Hager, Bradford H.; Zuber, Maria T.; King, Scott D.; Bland, Michael T.; Cristina De Sanctis, Maria; Preusker, Frank; Park, Ryan S.; Russell, Christopher T.


    Ceres, the largest body in the asteroid belt (940 km diameter), provides a unique opportunity to study the interior structure of a volatile-rich dwarf planet. Variations in a planetary body's subsurface rheology and density affect the rate of topographic relaxation. Preferential attenuation of long wavelength topography (≥150 km) on Ceres suggests that the viscosity of its crust decreases with increasing depth. We present finite element (FE) geodynamical simulations of Ceres to identify the internal structures and compositions that best reproduce its topography as observed by the NASA Dawn mission. We infer that Ceres has a mechanically strong crust with maximum effective viscosity ∼1025 Pa s. Combined with density constraints, this rheology suggests a crustal composition of carbonates or phyllosilicates, water ice, and at least 30 volume percent (vol.%) low-density, high-strength phases most consistent with salt and/or clathrate hydrates. The inference of these crustal materials supports the past existence of a global ocean, consistent with the observed surface composition. Meanwhile, we infer that the uppermost ≥60 km of the silicate-rich mantle is mechanically weak with viscosity avoided igneous differentiation due to late accretion or efficient heat loss through hydrothermal processes.

  2. Insights into interstitial flow, shear stress, and mass transport effects on ECM heterogeneity in bioreactor-cultivated engineered cartilage hydrogels. (United States)

    Chen, Tony; Buckley, Mark; Cohen, Itai; Bonassar, Lawrence; Awad, Hani A


    Interstitial flow in articular cartilage is secondary to compressive and shear deformations during joint motion and has been linked with the well-characterized heterogeneity in structure and composition of its extracellular matrix. In this study, we investigated the effects of introducing gradients of interstitial flow on the evolution of compositional heterogeneity in engineered cartilage. Using a parallel-plate bioreactor, we observed that Poiseuille flow stimulation of chondrocyte-seeded agarose hydrogels led to an increase in glycosaminoglycan and type II collagen deposition in the surface region of the hydrogel exposed to flow. Experimental measurements of the interstitial flow fields based on the fluorescence recovery after photobleaching technique suggested that the observed heterogeneity in composition is associated with gradients in interstitial flow in a boundary layer at the hydrogel surface. Interestingly, the interstitial flow velocity profiles were nonlinearly influenced by flow rate, which upon closer examination led us to the original observation that the apparent hydrogel permeability decreased exponentially with increased interfacial shear stress. We also observed that interstitial flow enhances convective mass transport irrespective of molecular size within the boundary layer near the hydrogel surface and that the convective contribution to transport diminishes with depth in association with interstitial flow gradients. The implications of the nonlinearly inverse relationship between the interfacial shear stress and the interstitial flux and permeability and its consequences for convective transport are important for tissue engineering, since porous scaffolds comprise networks of Poiseuille channels (pores) through which interstitial flow must navigate under mechanical stimulation or direct perfusion.

  3. Cartilage tissue engineering for degenerative joint disease. (United States)

    Nesic, Dobrila; Whiteside, Robert; Brittberg, Mats; Wendt, David; Martin, Ivan; Mainil-Varlet, Pierre


    Pain in the joint is often due to cartilage degeneration and represents a serious medical problem affecting people of all ages. Although many, mostly surgical techniques, are currently employed to treat cartilage lesions, none has given satisfactory results in the long term. Recent advances in biology and material science have brought tissue engineering to the forefront of new cartilage repair techniques. The combination of autologous cells, specifically designed scaffolds, bioreactors, mechanical stimulations and growth factors together with the knowledge that underlies the principles of cell biology offers promising avenues for cartilage tissue regeneration. The present review explores basic biology mechanisms for cartilage reconstruction and summarizes the advances in the tissue engineering approaches. Furthermore, the limits of the new methods and their potential application in the osteoarthritic conditions are discussed.

  4. Structural analysis of hepatitis B surface antigen by monoclonal antibodies. (United States)

    Ben-Porath, E; Wands, J R; Marciniak, R A; Wong, M A; Hornstein, L; Ryder, R; Canlas, M; Lingao, A; Isselbacher, K J


    A method has been developed for the analysis of hepatitis B surface antigen (HBsAg) antigenic structure at the molecular level that creates "fingerprints" or "signatures" of various hepatitis B viral (HBV) strains. This technique employs high affinity IgM and IgG monoclonal antibodies (anti-HBs) directed against distinct and separate determinants on HBsAg. In performing this antigenic structural analysis, separate binding curves for different monoclonal anti-HBs are generated by measuring immunoreactivity in serial dilutions of HBsAg-positive serum by radioimmunoassay. Since the HBsAg concentration in serum is unknown, the binding profiles of groups of samples are aligned by an iterative least-squares procedure to generate the numerical signature characteristic of the viral strain. The numerical signatures are then displayed on a computer-graphic plot. The signature profiles of HBsAg subtypes are a true reflection of their antigenic structure, and in vertical and horizontal transmission studies the molecular characteristics of the viral epitopes are conserved. By signature analysis we found substantial antigenic heterogeneity among the ayw3 strain both in the U.S. and France, as well as in populations of the Far East and Africa. Populations in Ethiopia, Gambia, and the Philippines were infected with two antigenically distinct HBV strains. In some newly identified HBV strains, it was found that epitopes identified by some monoclonal antibodies were absent or substantially reduced, which suggested that a genetic mutation may have occurred. Thus this study suggests that there is far more antigenic heterogeneity in HBV than previously recognized. These variants are antigenically distinct from each other at the epitope level, and were heretofore unrecognized by polyvalent anti-HBsAg antibodies.

  5. Superhydrophobic hierarchically structured surfaces in biology: evolution, structural principles and biomimetic applications. (United States)

    Barthlott, W; Mail, M; Neinhuis, C


    A comprehensive survey of the construction principles and occurrences of superhydrophobic surfaces in plants, animals and other organisms is provided and is based on our own scanning electron microscopic examinations of almost 20 000 different species and the existing literature. Properties such as self-cleaning (lotus effect), fluid drag reduction (Salvinia effect) and the introduction of new functions (air layers as sensory systems) are described and biomimetic applications are discussed: self-cleaning is established, drag reduction becomes increasingly important, and novel air-retaining grid technology is introduced. Surprisingly, no evidence for lasting superhydrophobicity in non-biological surfaces exists (except technical materials). Phylogenetic trees indicate that superhydrophobicity evolved as a consequence of the conquest of land about 450 million years ago and may be a key innovation in the evolution of terrestrial life. The approximate 10 million extant species exhibit a stunning diversity of materials and structures, many of which are formed by self-assembly, and are solely based on a limited number of molecules. A short historical survey shows that bionics (today often called biomimetics) dates back more than 100 years. Statistical data illustrate that the interest in biomimetic surfaces is much younger still. Superhydrophobicity caught the attention of scientists only after the extreme superhydrophobicity of lotus leaves was published in 1997. Regrettably, parabionic products play an increasing role in marketing.This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'. © 2016 The Author(s).

  6. Superhydrophobic hierarchically structured surfaces in biology: evolution, structural principles and biomimetic applications (United States)

    Mail, M.; Neinhuis, C.


    A comprehensive survey of the construction principles and occurrences of superhydrophobic surfaces in plants, animals and other organisms is provided and is based on our own scanning electron microscopic examinations of almost 20 000 different species and the existing literature. Properties such as self-cleaning (lotus effect), fluid drag reduction (Salvinia effect) and the introduction of new functions (air layers as sensory systems) are described and biomimetic applications are discussed: self-cleaning is established, drag reduction becomes increasingly important, and novel air-retaining grid technology is introduced. Surprisingly, no evidence for lasting superhydrophobicity in non-biological surfaces exists (except technical materials). Phylogenetic trees indicate that superhydrophobicity evolved as a consequence of the conquest of land about 450 million years ago and may be a key innovation in the evolution of terrestrial life. The approximate 10 million extant species exhibit a stunning diversity of materials and structures, many of which are formed by self-assembly, and are solely based on a limited number of molecules. A short historical survey shows that bionics (today often called biomimetics) dates back more than 100 years. Statistical data illustrate that the interest in biomimetic surfaces is much younger still. Superhydrophobicity caught the attention of scientists only after the extreme superhydrophobicity of lotus leaves was published in 1997. Regrettably, parabionic products play an increasing role in marketing. This article is part of the themed issue ‘Bioinspired hierarchically structured surfaces for green science’. PMID:27354736

  7. Cartilage repair in the degenerative ageing knee (United States)

    Brittberg, Mats; Gomoll, Andreas H; Canseco, José A; Far, Jack; Lind, Martin; Hui, James


    Background and purpose Cartilage damage can develop due to trauma, resulting in focal chondral or osteochondral defects, or as more diffuse loss of cartilage in a generalized organ disease such as osteoarthritis. A loss of cartilage function and quality is also seen with increasing age. There is a spectrum of diseases ranging from focal cartilage defects with healthy surrounding cartilage to focal lesions in degenerative cartilage, to multiple and diffuse lesions in osteoarthritic cartilage. At the recent Aarhus Regenerative Orthopaedics Symposium (AROS) 2015, regenerative challenges in an ageing population were discussed by clinicians and basic scientists. A group of clinicians was given the task of discussing the role of tissue engineering in the treatment of degenerative cartilage lesions in ageing patients. We present the outcomes of our discussions on current treatment options for such lesions, with particular emphasis on different biological repair techniques and their supporting level of evidence. Results and interpretation Based on the studies on treatment of degenerative lesions and early OA, there is low-level evidence to suggest that cartilage repair is a possible treatment for such lesions, but there are conflicting results regarding the effect of advanced age on the outcome. We concluded that further improvements are needed for direct repair of focal, purely traumatic defects before we can routinely use such repair techniques for the more challenging degenerative lesions. Furthermore, we need to identify trigger mechanisms that start generalized loss of cartilage matrix, and induce subchondral bone changes and concomitant synovial pathology, to maximize our treatment methods for biological repair in degenerative ageing joints. PMID:27910738

  8. Relationship between patellar mobility and patellofemoral joint cartilage degeneration after anterior cruciate ligament reconstruction. (United States)

    Ota, Susumu; Kurokouchi, Kazutoshi; Takahashi, Shigeo; Yoda, Masaki; Yamamoto, Ryuichiro; Sakai, Tadahiro


    Patellofemoral cartilage degeneration is a potential complication of anterior cruciate ligament reconstruction (ACLR) surgery. Hypomobility of the patella in the coronal plane is often observed after ACLR. Few studies, however, have examined the relationship between cartilage degeneration in the patellofemoral joint and mobility after ACLR. The present study investigated 1) the coronal mobility of the patella after ACLR, 2) the relationship between patellar mobility and cartilage degeneration of the patellofemoral joint, and 3) the relationship between patellar mobility and knee joint function after ACLR. Forty patients who underwent medial hamstring-based ACLR participated in the study. Lateral and medial patellar displacements were assessed with a modified patellofemoral arthrometer, and the absolute values of the displacements were normalized to patient height. The International Cartilage Repair Society (ICRS) cartilage injury classification of the patellar and femoral (trochlear) surfaces, and the Lysholm Knee Scoring Scale were used to evaluate knee function. Lateral and medial patellar displacements were reduced compared with the non-operated knee at the second-look arthroscopy and bone staple extraction operation (second operation; 24.4 ± 7.9 months after ACLR, Pmobility, however, were significantly correlated with the ICRS grade or the Lysholm score. Although patellar mobility at approximately 2 years after ACLR was decreased compared to the non-operated knee, small displacement of the patella was not related to cartilage degeneration or knee joint function at the time of the second operation.

  9. Osteoarthritis-derived chondrocytes are a potential source of multipotent progenitor cells for cartilage tissue engineering. (United States)

    Oda, Tomoyuki; Sakai, Tadahiro; Hiraiwa, Hideki; Hamada, Takashi; Ono, Yohei; Nakashima, Motoshige; Ishizuka, Shinya; Matsukawa, Tetsuya; Yamashita, Satoshi; Tsuchiya, Saho; Ishiguro, Naoki


    The natural healing capacity of damaged articular cartilage is poor, rendering joint surface injuries a prime target for regenerative medicine. While autologous chondrocyte or mesenchymal stem cell (MSC) implantation can be applied to repair cartilage defects in young patients, no appropriate long-lasting treatment alternative is available for elderly patients with osteoarthritis (OA). Multipotent progenitor cells are reported to present in adult human articular cartilage, with a preponderance in OA cartilage. These facts led us to hypothesize the possible use of osteoarthritis-derived chondrocytes as a cell source for cartilage tissue engineering. We therefore analyzed chondrocyte- and stem cell-related markers, cell growth rate, and multipotency in OA chondrocytes (OACs) and bone marrow-derived MSCs, along with normal articular chondrocytes (ACs) as a control. OACs demonstrated similar phenotype and proliferation rate to MSCs. Furthermore, OACs exhibited multilineage differentiation ability with a greater chondrogenic differentiation ability than MSCs, which was equivalent to ACs. We conclude that chondrogenic capacity is not significantly affected by OA, and OACs could be a potential source of multipotent progenitor cells for cartilage tissue engineering. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Middle ear mechanics of cartilage tympanoplasty evaluated by laser holography and vibrometry. (United States)

    Aarnisalo, Antti A; Cheng, Jeffrey T; Ravicz, Michael E; Hulli, Nesim; Harrington, Ellery J; Hernandez-Montes, Maria S; Furlong, Cosme; Merchant, Saumil N; Rosowski, John J


    To assess the effects of thickness and position of cartilage used to reconstruct the tympanic membrane (TM) using a novel technique, time-averaged laser holography. Cartilage is commonly used in TM reconstruction to prevent formation of retraction pockets. The thickness, position, and shape of the cartilage graft may adversely affect TM motion and hearing. We sought to systematically investigate these parameters in an experimental setting. Computer-assisted optoelectronic laser holography was used in 4 human cadaveric temporal bones to study sound-induced TM motion for 500 Hz to 8 kHz. Stapes velocity was measured with a laser Doppler vibrometer. Baseline (control) measurements were made with the TM intact. Measurements were repeated after a 0.5- or 1.0-mm-thick oval piece of conchal cartilage was placed on the medial TM surface in the posterior-superior quadrant. The cartilage was rotated so that it was either in contact with the bony tympanic rim and manubrium or not. At frequencies less than 4 kHz, the cartilage graft had only minor effects on the overall TM fringe patterns. The different conditions had no effects on stapes velocity. Greater than 4 kHz, TM motion was reduced over the grafted TM, both with 0.5- and 1.0-mm-thick grafts. No significant differences in stapes velocity were seen with the 2 different thicknesses of cartilage compared with control. Computer-assisted optoelectronic laser holography is a promising technique to investigate middle ear mechanics after tympanoplasty. Such positioning may prevent postoperative TM retraction. These findings and conclusions apply to cartilage placed in the posterior-superior TM quadrant.

  11. Arthroscopic optical coherence tomography provides detailed information on articular cartilage lesions in horses. (United States)

    te Moller, N C R; Brommer, H; Liukkonen, J; Virén, T; Timonen, M; Puhakka, P H; Jurvelin, J S; van Weeren, P R; Töyräs, J


    Arthroscopy enables direct inspection of the articular surface, but provides no information on deeper cartilage layers. Optical coherence tomography (OCT), based on measurement of reflection and backscattering of light, is a diagnostic technique used in cardiovascular surgery and ophthalmology. It provides cross-sectional images at resolutions comparable to that of low-power microscopy. The aim of this study was to determine if OCT is feasible for advanced clinical assessment of lesions in equine articular cartilage during diagnostic arthroscopy. Diagnostic arthroscopy of 36 metacarpophalangeal joints was carried out ex vivo. Of these, 18 joints with varying degrees of cartilage damage were selected, wherein OCT arthroscopy was conducted using an OCT catheter (diameter 0.9 mm) inserted through standard instrument portals. Five sites of interest, occasionally supplemented with other locations where defects were encountered, were arthroscopically graded according to the International Cartilage Repair Society (ICRS) classification system. The same sites were evaluated qualitatively (ICRS classification and morphological description of the lesions) and quantitatively (measurement of cartilage thickness) on OCT images. OCT provided high resolution images of cartilage enabling determination of cartilage thickness. Comparing ICRS grades determined by both arthroscopy and OCT revealed poor agreement. Furthermore, OCT visualised a spectrum of lesions, including cavitation, fibrillation, superficial and deep clefts, erosion, ulceration and fragmentation. In addition, with OCT the arthroscopically inaccessible area between the dorsal MC3 and P1 was reachable in some cases. Arthroscopically-guided OCT provided more detailed and quantitative information on the morphology of articular cartilage lesions than conventional arthroscopy. OCT could therefore improve the diagnostic value of arthroscopy in equine orthopaedic surgery. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Distribution of Basement Membrane Molecules, Laminin and Collagen Type IV, in Normal and Degenerated Cartilage Tissues (United States)

    Toh, Wei Seong; Gomoll, Andreas H.; Olsen, Bjørn Reino; Spector, Myron


    Objective: The objective of the present study was to investigate the presence and distribution of 2 basement membrane (BM) molecules, laminin and collagen type IV, in healthy and degenerative cartilage tissues. Design: Normal and degenerated tissues were obtained from goats and humans, including articular knee cartilage, the intervertebral disc, and meniscus. Normal tissue was also obtained from patella-tibial enthesis in goats. Immunohistochemical analysis was performed using anti-laminin and anti–collagen type IV antibodies. Human and goat skin were used as positive controls. The percentage of cells displaying the pericellular presence of the protein was graded semiquantitatively. Results: When present, laminin and collagen type IV were exclusively found in the pericellular matrix, and in a discrete layer on the articulating surface of normal articular cartilage. In normal articular (hyaline) cartilage in the human and goat, the proteins were found co-localized pericellularly. In contrast, in human osteoarthritic articular cartilage, collagen type IV but not laminin was found in the pericellular region. Nonpathological fibrocartilaginous tissues from the goat, including the menisci and the enthesis, were also positive for both laminin and collagen type IV pericellularly. In degenerated fibrocartilage, including intervertebral disc, as in degenerated hyaline cartilage only collagen type IV was found pericellularly around chondrocytes but with less intense staining than in non-degenerated tissue. In calcified cartilage, some cells were positive for laminin but not type IV collagen. Conclusions: We report differences in expression of the BM molecules, laminin and collagen type IV, in normal and degenerative cartilaginous tissues from adult humans and goats. In degenerative tissues laminin is depleted from the pericellular matrix before collagen type IV. The findings may inform future studies of the processes underlying cartilage degeneration and the functional

  13. Effects of Surface Chemistry on the Porous Structure of Coal

    Energy Technology Data Exchange (ETDEWEB)

    Radovic, Ljubisa R; Hatcher, Patrick G


    In this report, 129 Xe nuclear magnetic resonance spectroscopy of xenon gas adsorbed in coal is used to describe some poorly understood features of coal microporous structure, particularly in establishing that a connected network exists, the type of connectivity, and its changes with the rank of coal. Micropore size scale and distribution are also considered. Two methods are developed which are new and versatile tools for the investigation of porous structure. Both utilize xenon gas that is in motion, while undergoing diffusion or exchange in coal, to describe the connectivity of the micropore structure of coal. Time tracking of the adsorption process by NMR, selective saturation, and saturation transfer techniques were used to obtain new information on the coal rank dependence of porous structure. In addition, an existing 129 Xe chemical shift-pore diameter model was used to calculate micropore diameters for coals, as well as for a microporous carbon, before and after pore-size alteration. In the initial study performed, straightforward 129 Xe NMR spectra at equilibrium xenon adsorption at a series of pressures were acquired for a rank-varied set of six coals. Acquisition of the NMR signal as an echo was tested and found to improve spectral quality. The spectra were used to calculate micropore diameters for the six coals. These range from 5.6 to 7.5 and exhibit a minimum value for the intermediate coal rank. The smallest pores occur in coals of about 82-85% carbon; at both lower and higher coal ranks, the average micropore size tends to be larger. The changes in the spectra with coal rank and surface area were explored. Signal linewidths were found to decrease with increasing coal rank and were interpreted in terms of increasing chemical or physical homogeneity of the coal as rank increases. The packing density of powdered coal was found to alter the spectral appearance in a high volatile bituminous coal, which is preliminary evidence that exchange affects the

  14. Cartilage stem/progenitor cells are activated in osteoarthritis via interleukin-1β/nerve growth factor signaling. (United States)

    Jiang, Yangzi; Hu, Changchang; Yu, Shuting; Yan, Junwei; Peng, Hsuan; Ouyang, Hong Wei; Tuan, Rocky S


    Interleukin-1β (IL-1β) and nerve growth factor (NGF) are key regulators in the pathogenesis of inflammatory arthritis; specifically, IL-1β is involved in tissue degeneration and NGF is involved in joint pain. However, the cellular and molecular interactions between IL-1β and NGF in articular cartilage are not known. Cartilage stem/progenitor cells (CSPCs) have recently been identified in osteoarthritic (OA) cartilage on the basis of their migratory properties. Here we hypothesize that IL-1β/NGF signaling is involved in OA cartilage degeneration by targeting CSPCs. NGF and NGF receptor (NGFR: TrkA and p75NTR) expression in healthy and OA human articular cartilage and isolated chondrocytes was determined by immunostaining, qRT-PCR, flow cytometry and western blot. Articular cartilage derived stem/progenitor cells were collected and identified by stem/progenitor cell characteristics. 3D-cultured CSPC pellets and cartilage explants were treated with NGF and NGF neutralizing antibody, and extracellular matrix changes were examined by sulfated glycosaminoglycan (GAG) release and MMP expression and activity. Expression of NGF, TrkA and p75NTR was found to be elevated in human OA cartilage. Cellular changes upon IL-1β and/or NGF treatment were then examined. NGF mRNA and NGFR proteins levels were upregulated in cultured chondrocytes exposed to IL-1β. NGF was chemotactic for cells isolated from OA cartilage. Cells isolated on the basis of their chemotactic migration towards NGF demonstrated stem/progenitor cell characteristics, including colony-forming ability, multi-lineage differentiation potential, and stem cell surface markers. The effects of NGF perturbation in cartilage explants and 3D-cultured CSPCs were next analyzed. NGF treatment resulted in extracellular matrix catabolism indicated by increased sGAG release and MMP expression and activity; conversely, treatment with NGF neutralizing antibody inhibited increased MMP levels, and enhanced tissue inhibitor of

  15. Development of an Electromechanical Grade to Assess Human Knee Articular Cartilage Quality. (United States)

    Sim, Sotcheadt; Hadjab, Insaf; Garon, Martin; Quenneville, Eric; Lavigne, Patrick; Buschmann, Michael D


    Quantitative assessments of articular cartilage function are needed to aid clinical decision making. Our objectives were to develop a new electromechanical grade to assess quantitatively cartilage quality and test its reliability. Electromechanical properties were measured using a hand-held electromechanical probe on 200 human articular surfaces from cadaveric donors and osteoarthritic patients. These data were used to create a reference electromechanical property database and to compare with visual arthroscopic International Cartilage Repair Society (ICRS) grading of cartilage degradation. The effect of patient-specific and location-specific characteristics on electromechanical properties was investigated to construct a continuous and quantitative electromechanical grade analogous to ICRS grade. The reliability of this novel grade was assessed by comparing it with ICRS grades on 37 human articular surfaces. Electromechanical properties were not affected by patient-specific characteristics for each ICRS grade, but were significantly different across the articular surface. Electromechanical properties varied linearly with ICRS grade, leading to a simple linear transformation from one scale to the other. The electromechanical grade correlated strongly with ICRS grade (r = 0.92, p < 0.0001). Additionally, the electromechanical grade detected lesions that were not found visually. This novel grade can assist the surgeon in assessing human knee cartilage by providing a quantitative and reliable grading system.

  16. Cartilage-like electrostatic stiffening of responsive cryogel scaffolds (United States)

    Offeddu, G. S.; Mela, I.; Jeggle, P.; Henderson, R. M.; Smoukov, S. K.; Oyen, M. L.


    Cartilage is a structural tissue with unique mechanical properties deriving from its electrically-charged porous structure. Traditional three-dimensional environments for the culture of cells fail to display the complex physical response displayed by the natural tissue. In this work, the reproduction of the charged environment found in cartilage is achieved using polyelectrolyte hydrogels based on polyvinyl alcohol and polyacrylic acid. The mechanical response and morphology of microporous physically-crosslinked cryogels are compared to those of heat-treated chemical gels made from the same polymers, as a result of pH-dependent swelling. In contrast to the heat-treated chemically-crosslinked gels, the elastic modulus of the physical cryogels was found to increase with charge activation and swelling, explained by the occurrence of electrostatic stiffening of the polymer chains at large charge densities. At the same time, the permeability of both materials to fluid flow was impaired by the presence of electric charges. This cartilage-like mechanical behavior displayed by responsive cryogels can be reproduced in other polyelectrolyte hydrogel systems to fabricate biomimetic cellular scaffolds for the repair of the tissue.

  17. Application of an acoustofluidic perfusion bioreactor for cartilage tissue engineering


    Li, Siwei; Glynne-Jones, Peter; Andriotis, Orestis G.; Ching, Kuan Y.; Jonnalagadda, Umesh S.; Oreffo, Richard O.C.; Hill, Martyn; Tare, Rahul S.


    Cartilage grafts generated using conventional static tissue engineering strategies are characterised by low cell viability, suboptimal hyaline cartilage formation and, critically, inferior mechanical competency, which limit their application for resurfacing articular cartilage defects. To address the limitations of conventional static cartilage bioengineering strategies and generate robust, scaffold-free neocartilage grafts of human articular chondrocytes, the present study utilised custom-bu...

  18. Surface Structure Study of Crystal Hydroxy-Apatite from Fluorosis Enamels


    Abdillah Imron Nasution; Harun Asyiq Gunawan; Sri Angky Soekanto


    Fluorosis is a condition due to ingestion of excessive amounts of fluor which can cause the change in tooth structure and strength. However, there is still lack of explanation on the surface structure of crystal hydroxyapatite that influences the microscopic characteristic of fluorosis enamel. Objectives: To investigate the surface structure of crystal hydroxy-apatite in fluorosis enamel. Materials and Methods: Determination of fluor concentration and the surface structure of normal and fluor...

  19. Effects of Chondroitinase ABC-Mediated Proteoglycan Digestion on Decellularization and Recellularization of Articular Cartilage.

    Directory of Open Access Journals (Sweden)

    Catherine A Bautista

    Full Text Available Articular cartilage has a limited capacity to heal itself and thus focal defects often result in the development of osteoarthritis. Current cartilage tissue engineering strategies seek to regenerate injured tissue by creating scaffolds that aim to mimic the unique structure and composition of native articular cartilage. Decellularization is a novel strategy that aims to preserve the bioactive factors and 3D biophysical environment of the native extracellular matrix while removing potentially immunogenic factors. The purpose of this study was to develop a procedure that can enable decellularization and recellularization of intact articular cartilage matrix. Full-thickness porcine articular cartilage plugs were decellularized with a series of freeze-thaw cycles and 0.1% (w/v sodium dodecyl sulfate detergent cycles. Chondroitinase ABC (ChABC was applied before the detergent cycles to digest glycosaminoglycans in order to enhance donor chondrocyte removal and seeded cell migration. Porcine synovium-derived mesenchymal stem cells were seeded onto the decellularized cartilage scaffolds and cultured for up to 28 days. The optimized decellularization protocol removed 94% of native DNA per sample wet weight, while collagen content and alignment were preserved. Glycosaminoglycan depletion prior to the detergent cycles increased removal of nuclear material. Seeded cells infiltrated up to 100 μm into the cartilage deep zone after 28 days in culture. ChABC treatment enhances decellularization of the relatively dense, impermeable articular cartilage by reducing glycosaminoglycan content. ChABC treatment did not appear to affect cell migration during recellularization under static, in vitro culture, highlighting the need for more dynamic seeding methods.

  20. {mu}-PIXE and SAXS studies at the bone-cartilage interface

    Energy Technology Data Exchange (ETDEWEB)

    Kaabar, W. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom)], E-mail:; Gundogdu, O. [Umuttepe Campus, University of Kocaeli, 41380, Kocaeli (Turkey); Laklouk, A. [Food Science Department, Al-Fateh Unversity, Tripoli (Libyan Arab Jamahiriya); Bunk, O. [Swiss Light Source, Paul Scherrer Institute, 5232 Villigen (Switzerland); Pfeiffer, F. [Swiss Light Source, Paul Scherrer Institute, 5232 Villigen (Switzerland); Ecole Polytechnique Federale de Lausanne, 1015 Lausanne (Switzerland); Farquharson, M.J. [Department of Radiography, City University, London EC1V OHB (United Kingdom); Bradley, D.A. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom)


    Micro Proton Induced X-ray Emission ({mu}-PIXE) analysis has been employed herein in investigating and quantifying the distribution of a number of essential elements in thin human diseased articular cartilage sections affected by osteoarthritis (OA). Various cations Ca, P and Zn have been reported to play an important role both in the normal growth and remodelling of articular cartilage and subchondral bone as well as in the degenerative and inflammatory processes associated with the disease; they act as co-factors of a class of enzymes known as metalloproteinases which are believed to be active during the initiation, progress and remodelling processes associated with osteoarthritis. Other important enzymes such as alkaline phosphatase are associated with cartilage mineralization. Synchrotron radiation X-ray fluorescence (SR-XRF) for mapping of elemental distributions in bone and cartilage has also been employed by the present group and others. In the current investigations using the cSAXS beamline at the Swiss light source, Small-Angle X-ray Scattering (SAXS) was carried out on decalcified human articular cartilage to explore the structural and organizational changes of collagen networks in diseased articular cartilage.

  1. Macroscopical, Histological, and Characterization of Nonosteoarthritic Versus Osteoarthritic Hip Joint Cartilage

    Directory of Open Access Journals (Sweden)

    Jessica Badendick


    Full Text Available Osteoarthritis (OA might affect chondrocyte culture characteristics and complement expression. Therefore, this study addressed the interrelation between macroscopical and microscopical structure, complement expression, and chondrocyte culture characteristics in non-OA and OA cartilage. Femoral head cartilage samples harvested from patients with femoral neck fractures (FNFs and OA were analyzed for macroscopical alterations using an in-house scoring system, graded histologically (Mankin score, and immunolabeled for complement regulatory proteins (CRPs and receptors. Morphology of monolayer cultured chondrocytes isolated from a subset of samples was assessed. The macroscopical score distinguished the FNF and OA cartilage samples and correlated significantly with the histological results. Chondrocyte phenotype from FNF or OA cartilage differed. Complement receptor C5aR, CRPs CD55 and CD59, and weakly receptor C3AR were detected in the investigated FNF and OA cartilage, except for CD46, which was detected in only two of the five investigated donors. The in-house score also allows inexperienced observers to distinguish non-OA and OA cartilage for experimental purposes.

  2. Environmental temperature impact on bone and cartilage growth. (United States)

    Serrat, Maria A


    Environmental temperature can have a surprising impact on extremity growth in homeotherms, but the underlying mechanisms have remained elusive for over a century. Limbs of animals raised at warm ambient temperature are significantly and permanently longer than those of littermates housed at cooler temperature. These remarkably consistent lab results closely resemble the ecogeographical tenet described by Allen's "extremity size rule," that appendage length correlates with temperature and latitude. This phenotypic growth plasticity could have adaptive significance for thermal physiology. Shortened extremities help retain body heat in cold environments by decreasing surface area for potential heat loss. Homeotherms have evolved complex mechanisms to maintain tightly regulated internal temperatures in challenging environments, including "facultative extremity heterothermy" in which limb temperatures can parallel ambient. Environmental modulation of tissue temperature can have direct and immediate consequences on cell proliferation, metabolism, matrix production, and mineralization in cartilage. Temperature can also indirectly influence cartilage growth by modulating circulating levels and delivery routes of essential hormones and paracrine regulators. Using an integrated approach, this article synthesizes classic studies with new data that shed light on the basis and significance of this enigmatic growth phenomenon and its relevance for treating human bone elongation disorders. Discussion centers on the vasculature as a gateway to understanding the complex interconnection between direct (local) and indirect (systemic) mechanisms of temperature-enhanced bone lengthening. Recent advances in imaging modalities that enable the dynamic study of cartilage growth plates in vivo will be key to elucidating fundamental physiological mechanisms of long bone growth regulation. © 2014 American Physiological Society.

  3. Tribology approach to the engineering and study of articular cartilage. (United States)

    Wimmer, Markus A; Grad, Sibylle; Kaup, Thomas; Hänni, Markus; Schneider, Erich; Gogolewski, Sylwester; Alini, Mauro


    This study has been based on the assumption that articular motion is an important aspect of mechanotransduction in synovial joints. For this reason a new bioreactor concept, able to reproduce joint kinematics more closely, has been designed. The prototype consists of a rotating scaffold and/or cartilage pin, which is pressed onto an orthogonally rotating ball. By oscillating pin and ball in phase difference, elliptical displacement trajectories are generated that are similar to the motion paths occurring in vivo. Simultaneously, dynamic compression may be applied with a linear actuator, while two-step-motors generate the rotation of pin and ball. The whole apparatus is placed in an incubator. The control station is located outside. Preliminary investigations at the gene expression level demonstrated promising results. Compared with free-swelling control and/or simply compression-loaded samples, chondrocyte-seeded scaffolds as well as nasal cartilage explants exposed to interface motion both showed elevated levels of cartilage oligomeric matrix protein mRNA. The final design of the bioreactor will include four individual stations in line, which will facilitate the investigation of motion-initiated effects at the contacting surfaces in more detail.

  4. Photonic bandgap structures for long-range surface plasmon polaritons

    DEFF Research Database (Denmark)

    Bozhevolnyi, Sergey I.; Boltasseva, Alexandra; Søndergaard, Thomas


    Propagation of long-range surface plasmon polaritons (LR-SPPs) along periodically thickness-modulated metal stripes embedded in dielectric is studied both theoretically and experimentally for light wavelengths in the telecom range. We demonstrate that symmetric (with respect to the film surface) nm...... of achieving a full bandgap (in the surface plane) for LR-SPPs are also discussed....

  5. Importance of surface structure on dissolution of fluorite

    DEFF Research Database (Denmark)

    Godinho, Jose; Piazolo, Sandra; Balic Zunic, Tonci


    of dissolution. Results are analyzed in terms of changes in surface area, surface reactivity and dissolution rates. All surfaces studied present fast changes in topography during the initial 200 h of dissolution. The controlling factors that cause the development of topography are the stability of the step edges...

  6. Structural characterisations of AlN/diamond structures used for surface acoustic wave device applications (United States)

    Mortet, V.; Elmazria, O.; Nesládek, M.; Elhakiki, M.; Vanhoyland, G.; D'Haen, J.; D'Olieslaeger, M.; Alnot, P.


    Diamond based surface acoustic wave (SAW) devices are extremely versatile devices that are just beginning to realize their commercial potential for use from sensors till high frequency (HF) filters for wireless telecommunications. One of the most promising piezoelectric materials for diamond based HF-SAW devices is aluminium nitride (AlN) thin film. The ability of AlN and diamond to be used for SAW applications depends both on the piezoelectric AlN layer properties and the diamond substrate properties. In this work, optimised piezoelectric (002) oriented AlN layers have been deposited on polycrystalline diamond substrates aiming at HF-SAW filter applications. CVD Polycrystalline diamond layers were deposited on silicon substrates by microwave plasma enhanced chemical vapour deposition (MW-PECVD). SAW filters with unique characteristics have been obtained due to exceptional diamond's mechanical properties [1, 2]. One of the important characteristics of CVD diamond substrate is concerns its surface roughness. Smooth diamond surfaces were obtained without polishing by a wet chemical etching of the silicon substrate at the diamond layer nucleation side. Very low surface roughness (RMS 1 nm) can be achieved by this technique for bias enhanced nucleated (BEN) (BEN) samples. In this paper, we report the structural characterization of the AlN films and diamond substrates by X-ray diffraction, atomic force microscopy, and transmission electron microscopy methods. (

  7. Structural characterisations of AlN/diamond structures used for surface acoustic wave device applications

    Energy Technology Data Exchange (ETDEWEB)

    Mortet, V.; Vanhoyland, G. [Institute for Materials Research (IMO), Limburgs Universitair Centrum, Wetenschapspark 1, B-3590 Diepenbeek (Belgium); Elmazria, O.; Elhakiki, M.; Alnot, P. [LPMIA - Universite H. Poincare - Nancy I, F-54506 Vandoeuvre-les-Nancy Cedex (France); Nesladek, M.; D' Olieslaeger, M. [Institute for Materials Research (IMO), Limburgs Universitair Centrum, Wetenschapspark 1, B-3590 Diepenbeek (Belgium); Division IMOMEC, IMEC vzw, Wetenschapspark 1, B-3590 Diepenbeek (Belgium); D' Haen, J. [Division IMOMEC, IMEC vzw, Wetenschapspark 1, B-3590 Diepenbeek (Belgium)


    Diamond based surface acoustic wave (SAW) devices are extremely versatile devices that are just beginning to realize their commercial potential for use from sensors till high frequency (HF) filters for wireless telecommunications. One of the most promising piezoelectric materials for diamond based HF-SAW devices is aluminium nitride (AlN) thin film. The ability of AlN and diamond to be used for SAW applications depends both on the piezoelectric AlN layer properties and the diamond substrate properties. In this work, optimised piezoelectric (002) oriented AlN layers have been deposited on polycrystalline diamond substrates aiming at HF-SAW filter applications. CVD Polycrystalline diamond layers were deposited on silicon substrates by microwave plasma enhanced chemical vapour deposition (MW-PECVD). SAW filters with unique characteristics have been obtained due to exceptional diamond's mechanical properties [1, 2]. One of the important characteristics of CVD diamond substrate is concerns its surface roughness. Smooth diamond surfaces were obtained without polishing by a wet chemical etching of the silicon substrate at the diamond layer nucleation side. Very low surface roughness (R{sub MS} {<=}1 nm) can be achieved by this technique for bias enhanced nucleated (BEN) (BEN) samples. In this paper, we report the structural characterization of the AlN films and diamond substrates by X-ray diffraction, atomic force microscopy, and transmission electron microscopy methods. (copyright 2003 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Does intraarticular inflammation predict biomechanical cartilage properties? (United States)

    Waldstein, Wenzel; Perino, Giorgio; Jawetz, Shari T; Gilbert, Susannah L; Boettner, Friedrich


    Intact cartilage in the lateral compartment is an important requirement for medial unicompartmental knee arthroplasty (UKA). Progression of cartilage degeneration in the lateral compartment is a common failure mode of medial UKA. Little is known about factors that influence the mechanical properties of lateral compartment cartilage. The purposes of this study were to answer the following questions: (1) Does the synovial fluid white blood cell count predict the biomechanical properties of macroscopically intact cartilage of the distal lateral femur? (2) Is there a correlation between MRI grading of synovitis and the biomechanical properties of macroscopically intact cartilage? (3) Is there a correlation between the histopathologic assessment of the synovium and the biomechanical properties of macroscopically intact cartilage? The study included 84 patients (100 knees) undergoing primary TKA for varus osteoarthritis between May 2010 and January 2012. All patients underwent preoperative MRI to assess the degree of synovitis. During surgery, the cartilage of the distal lateral femur was assessed macroscopically using the Outerbridge grading scale. In knees with an Outerbridge grade of 0 or 1, osteochondral plugs were harvested from the distal lateral femur for biomechanical and histologic assessment. The synovial fluid was collected to determine the white blood cell count. Synovial tissue was taken for histologic evaluation of the degree of synovitis. The mean aggregate modulus and the mean dynamic modulus were significantly greater in knees with 150 or less white blood cells/mL synovial fluid compared with knees with greater than 150 white blood cells/mL synovial fluid. There was no correlation among MRI synovitis grades, histopathologic synovitis grades, and biomechanical cartilage properties. The study suggests that lateral compartment cartilage in patients with elevated synovial fluid white blood cell counts has a reduced ability to withstand compressive loads

  9. An equine joint friction test model using a cartilage-on-cartilage arrangement. (United States)

    Noble, Prisca; Collin, Bernard; Lecomte-Beckers, Jacqueline; Magnée, Adrien; Denoix, Jean M; Serteyn, Didier


    This study describes an equine joint friction test using a cartilage-on-cartilage arrangement and investigates the influence of age and load on the frictional response. Osteochondral plugs were extracted from equine shoulder joints (2-5 years, n=12; 10-14 years, n=15), and mounted in a pin-on-disc tribometer. The frictional response was then measured under constant conditions (2N; 20 degrees C; 5 mm/s), and with increasing load (2N, 5N, 10N). In all experiments, the friction coefficient of young cartilage was significantly (Plubrication remained stable, cartilage ageing may have been responsible for lubrication regime change. The cartilage-on-cartilage model could be used to better understand lubrication regime disturbances in healthy and diseased equine joints, and to test the efficacy of various bio-lubricant treatments. Copyright (c) 2008 Elsevier Ltd. All rights reserved.

  10. Does the epiphyseal cartilage of the long bones have one or two ossification fronts? (United States)

    Delgado-Martos, María Jesús; Touza Fernández, Alberto; Canillas, Fernando; Quintana-Villamandos, Begoña; Santos del Riego, Sergio; Delgado-Martos, Emilio; Martos-Rodriguez, Antonia; Delgado-Baeza, Emilio


    the juxtaposed bone plate and the epiphyseal cartilage, in which the chondrocytes that migrate from the germinal area play an important role in the mineralisation and ossification process of the juxtaposed bone plate, supports the hypothesis of a new ossification front in the epiphyseal layer of the epiphyseal plate. This hypothesis has several implications: (a) epiphyseal cartilage is a morphological entity with two different ossification fronts and two different functions, (b) epiphyseal cartilage may be a morphological structure with three parts: perichondrial ring, metaphyseal ossification front or growth plate, and epiphyseal ossification front, (c) all disease (traumatic or dysplastic) that affects some of these parts can have an impact on the morphology of the epiphyseal region of the bone, (d) there is a certain analogy between metaphyseal cartilage in amphibians and mammalian epiphyseal cartilage, although the former is not responsible for bone growth, (e) comparative histological and anatomy studies are also warranted, to shed light on the phylogenetic study of epiphyseal cartilage throughout the changes that occur in the animal species. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Three-dimensional polycaprolactone-hydroxyapatite scaffolds combined with bone marrow cells for cartilage tissue engineering. (United States)

    Wei, Bo; Yao, Qingqiang; Guo, Yang; Mao, Fengyong; Liu, Shuai; Xu, Yan; Wang, Liming


    The goal of this study was to investigate the chondrogenic potential of three-dimensional polycaprolactone-hydroxyapatite (PCL-HA) scaffolds loaded with bone marrow cells in vitro and the effect of PCL-HA scaffolds on osteochondral repair in vivo. Here, bone marrow was added to the prepared PCL-HA scaffolds and cultured in chondrogenic medium for 10 weeks. Osteochondral defects were created in the trochlear groove of 29 knees in 17 New Zealand white rabbits, which were then divided into four groups that underwent: implantation of PCL-HA scaffolds (left knee, n = 17; Group 1), microfracture (right knee, n = 6; Group 2), autologous osteochondral transplantation (right knee, n = 6; Group 3), and no treatment (right knee, n = 5; Control). Extracellular matrix produced by bone marrow cells covered the surface and filled the pores of PCL-HA scaffolds after 10 weeks in culture. Moreover, many cell-laden cartilage lacunae were observed, and cartilage matrix was concentrated in the PCL-HA scaffolds. After a 12-week repair period, Group 1 showed excellent vertical and lateral integration with host bone, but incomplete cartilage regeneration and matrix accumulation. An uneven surface of regenerated cartilage and reduced distribution of cartilage matrix were observed in Group 2. In addition, abnormal bone growth and unstable integration between repaired and host tissues were detected. For Group 3, the integration between transplanted and host cartilage was interrupted. Our findings indicate that the PCL-HA scaffolds loaded with bone marrow cells improved chondrogenesis in vitro and implantation of PCL-HA scaffolds for osteochondral repairenhanced integration with host bone. However, cartilage regeneration remained unsatisfactory. The addition of trophic factors or the use of precultured cell-PCL-HA constructs for accelerated osteochondral repair requires further investigation. © The Author(s) 2015.

  12. Calcite surface structure and reactivity: molecular dynamics simulations and macroscopic surface modelling of the calcite-water interface

    NARCIS (Netherlands)

    Wolthers, M.; Di Tommaso, D.; Du, Z.; de Leeuw, N.H.


    Calcite–water interactions are important not only in carbon sequestration and the global carbon cycle, but also in contaminant behaviour in calcite-bearing host rock and in many industrial applications. Here we quantify the effect of variations in surface structure on calcite surface reactivity.

  13. The effect of surface structure on Ag atom adsorption over CuO(111) surfaces: A first principles study (United States)

    Hu, Riming; Zhou, Xiaolong; Yu, Jie


    The interactions of Ag atom with different types of CuO(111) surface, including the perfect, oxygen-vacancy and precovered oxygen surfaces, have been systematically investigated using density functional theory (DFT) calculations to examine the effect of surface structures on Ag atom adsorption. The calculated results indicate that the Cu1-Cu1 bridge site and the oxygen-vacancy site are the active centres for atomic Ag adsorption on the perfect surface and the oxygen-vacancy surface respectively, while atomic Ag preferentially adsorbs at the Op site on the precovered oxygen surface. The activity of the CuO(111) surface for atomic Ag adsorption can be improved both on the perfect and oxygen-vacancy surfaces, while the activity of the CuO(111) surface for atomic Ag adsorption will be suppressed on precovered oxygen surfaces. Furthermore, the adsorption of NO on different CuO(111) surfaces with Ag adsorption was investigated, and the calculation results show that the adsorption of NO on an Ag-loaded CuO(111) surface is greater than that on the pure CuO(111) surface.

  14. Structure, biomimetics, and fluid dynamics of fish skin surfaces* (United States)

    Lauder, George V.; Wainwright, Dylan K.; Domel, August G.; Weaver, James C.; Wen, Li; Bertoldi, Katia


    The interface between the fluid environment and the surface of the body in swimming fishes is critical for both physiological and hydrodynamic functions. The skin surface in most species of fishes is covered with bony scales or toothlike denticles (in sharks). Despite the apparent importance of fish surfaces for understanding aquatic locomotion and near-surface boundary layer flows, relatively little attention has been paid to either the nature of surface textures in fishes or possible hydrodynamic effects of variation in roughness around the body surface within an individual and among species. Fish surfaces are remarkably diverse and in many bony fishes scales can have an intricate surface texture with projections, ridges, and comblike extensions. Shark denticles (or scales) are toothlike and project out of the skin to form a complexly textured surface that interacts with free-stream flow. Manufacturing biomimetic foils with fishlike surfaces allows hydrodynamic testing and we emphasize here the importance of dynamic test conditions where the effect of surface textures is assessed under conditions of self-propulsion. We show that simple two-dimensional foils with patterned cuts do not perform as well as a smooth control surface, but that biomimetic shark skin foils can swim at higher self-propelled speeds than smooth controls. When the arrangement of denticles on the foil surface is altered, we find that a staggered-overlapped pattern outperforms other arrangements. Flexible foils made of real shark skin outperform sanded controls when foils are moved with a biologically realistic motion program. We suggest that focus on the mechanisms of drag reduction by fish surfaces has been too limiting and an additional role of fish surface textures may be to alter leading edge vortices and flow patterns on moving surfaces in a way that enhances thrust. Analysis of water flow over an artificial shark skin foil under both static and dynamic conditions shows that a shear layer

  15. Cartilage invasion patterns in laryngeal cancer. (United States)

    Gómez Serrano, Manuel; Iglesias Moreno, María Cruz; Gimeno Hernández, Jesús; Ortega Medina, Luis; Martín Villares, Cristina; Poch Broto, Joaquín


    The cartilaginous invasion determines the T and is one of the most common sources of mistake in tumor staging. Also it is of great importance when planning any therapeutic alternative. In the latest revision of the TNM classification a clear distinction is made between infiltration of cartilage without going through it, considered a T3 recently and that would be a T4 according to the previous classification, and those going through the cartilage, classified as T4a. While this classification makes the difference in depth of infiltration, it does not emphasize the extent of invasion. This paper provides a detailed description of the laryngeal cartilage tumor infiltration by whole organ serial section in which the invasion is considered both horizontal (transcartilaginous) and vertical (extent of invasion) and establishing patterns of three-dimensional infiltration of the cartilage. This is a cross-sectional study of prevalence. 275 records of patients treated for laryngeal squamous cell carcinoma between 1995 and 2000 were reviewed. The pathological processing of laryngectomy surgical specimens was performed following the method of whole organ serial section described by G. F. Tucker. The following patterns of cartilaginous infiltration were defined: (1) transcartilaginous infiltration; (2a) partial focal infiltration of the cartilage: infiltration not going through the cartilage but occupying one third or less of its extent; (2b) partial extensive infiltration of the cartilage: infiltration occupying two thirds or more of its length and (3) no cartilage infiltration: tumor in contact with the cartilage (paraglottic space) but without affecting it. 161 patients met the inclusion criteria. The most frequent tumor location was supraglottic (58 cases) followed by glottic (47). 109 patients (67.7 %) were treated with total laryngectomy. Partial surgical techniques were performed in the remaining cases. TNM tumor staging was performed according to the results of

  16. Computational fluid dynamics modeling of momentum transport in rotating wall perfused bioreactor for cartilage tissue engineering. (United States)

    Cinbiz, Mahmut N; Tığli, R Seda; Beşkardeş, Işil Gerçek; Gümüşderelioğlu, Menemşe; Colak, Uner


    In this study, computational fluid dynamics (CFD) analysis of a rotating-wall perfused-vessel (RWPV) bioreactor is performed to characterize the complex hydrodynamic environment for the simulation of cartilage development in RWPV bioreactor in the presence of tissue-engineered cartilage constructs, i.e., cell-chitosan scaffolds. Shear stress exerted on chitosan scaffolds in bioreactor was calculated for different rotational velocities in the range of 33-38 rpm. According to the calculations, the lateral and lower surfaces were exposed to 0.07926-0.11069 dyne/cm(2) and 0.05974-0.08345 dyne/cm(2), respectively, while upper surfaces of constructs were exposed to 0.09196-0.12847 dyne/cm(2). Results validate adequate hydrodynamic environment for scaffolds in RWPV bioreactor for cartilage tissue development which concludes the suitability of operational conditions of RWPV bioreactor. Copyright © 2010 Elsevier B.V. All rights reserved.

  17. Cell-Based Treatment for the Management of Articular Cartilage Injuries Where Are We? (United States)

    Rossy, William; Strauss, Eric


    Articular cartilage is a specialized tissue that lines the surface of joints. Injuries to articular cartilage pose challenges due to poor healing potential. Focal cartilage defects are typically the result of high impact or repetitive loads to the articular surface. They tend to occur in the younger, active population and have been shown to cause swelling, pain, and joint dysfunction. Although the natural history of these lesions has never been definitively elucidated in the literature, clinical experience suggests that if left untreated, these lesions will demonstrate an inability to heal and may lead to prolonged increased articular peak stresses, which in turn may lead to pain and significant limitations in the future. The purpose of the present review is to provide the most current treatment options for these injuries and review the literature supporting their use.

  18. Surface structures from low energy electron diffraction: Atoms, small molecules and an ordered ice film on metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Materer, Nicholas F. [Univ. of California, Berkeley, CA (United States)


    We investigated the surface bonding of various adsorbates (0, S, C2H3 and NO) along with the resulting relaxation of the Pt(111) surface using low energy electron diffiraction (LEED). LEED experiments have been performed on these ordered overlayers along with theoretical structural analysis using automated tensor LEED (ATLEED). The resulting surface structures of these ordered overlayers exhibit similar adsorbate-induced relaxations. In all cases the adsorbate occupies the fcc hollow site and induces an approximately 0.1 A buckling of the metal surface. The three metal atoms directly bonded to the adsorbate are ``pulled`` out of the surface and the metal atom that is not bound to the adsorbate is `pushed`` inward. In order to understand the reliability of such details, we have carried out a comprehensive study of various non-structural parameters used in a LEED computation. We also studied the adsorption of water on the Pt(lll) surface. We ordered an ultra thin ice film on this surface. The film`s surface is found to be the (0001) face of hexagonal ice. This surface is apparently terminated by a full-bilayer, in which the uppermost water molecules have large vibrational amplitudes even at temperatures as low as 90 K. We examined two other metal surfaces besides Pt(111): Ni(111) and Fe(lll). On Ni(111), we have studied the surface under a high coverage of NO. On both Ni(111) and Pt(111) NO molecules occupy the hollow sites and the N-0 bond distances are practically identical. The challenging sample preparation of an Fe(111) surface has been investigated and a successful procedure has been obtained. The small interlayer spacing found on Fe(111) required special treatment in the LEED calculations. A new ATLEED program has been developed to handle this surface.

  19. Structural and spectroscopic studies of surfaces on the nanometre scale

    CERN Document Server

    Festy, F


    We have designed, built and tested a novel surface sensitive instrument, the Scanning Probe Energy Loss Spectrometer (SPELS). Based on a Scanning Tunnelling Microscope (STM) operating in field emission mode, it is capable of detecting and analysing the energy loss of the electrons emitted from the STM tip and backscattered from the sample surface. We have performed electron trajectory simulations of the emitted and backscattered electron for different tip radius and tip-sample separations. We discovered that the escaping trajectory of the backscattered electron is parallel to the sample surface. Operating at primary beam energy lower than 200V and tip- sample distance lower than 200nm, the SPELS have successfully recorded spectrum on different surfaces: contaminated Si(111), Si(111)-7x7, Highly Oriented Pyrolitic Graphite (HOPG) and gold evaporated on mica. The surface damages on HOPG and gold surfaces have been investigated. We have obtained backscattered electrons images and energy loss electron images on c...

  20. Structural health monitoring and remote sensing of transportation infrastructure using embedded frequency selective surfaces. (United States)


    The objective of this project was to investigate the use of Frequency Selective Surfaces (FSS) for structural health monitoring applications. Frequency Selective Surfaces (FSS) have long been used in the RF/microwave community to control scattering f...

  1. Reinforcement Toolbox, a Parametric Reinforcement Modelling Tool for Curved Surface Structures

    NARCIS (Netherlands)

    Lauppe, J.; Rolvink, A.; Coenders, J.L.


    This paper presents a computational strategy and parametric modelling toolbox which aim at enhancing the design- and production process of reinforcement in freeform curved surface structures. The computational strategy encompasses the necessary steps of raising an architectural curved surface model

  2. Effects of surface plasmons in subwavelength metallic structures


    Iyer, Srinivasan


    The study of optical phenomena related to the strong electromagnetic response of noble metals (silver (Ag) and gold (Au) being most popular) over the last couple of decades has led to the emergence of a fast growing research area called plasmonics named after 'surface plasmons' which are electron density waves that propagate along the interface of a metal and a dielectric medium. Surface plasmons are formed by the coupling of light to the electrons on the metal surface subject to the fulfillm...

  3. The normal human chondro-osseous junctional region: evidence for contact of uncalcified cartilage with subchondral bone and marrow spaces

    Directory of Open Access Journals (Sweden)

    Stoddart Robert W


    Full Text Available Abstract Background The chondro-osseous junctional region of diarthrodial joints is peculiarly complex and may be considered to consist of the deepest layer of non-calcified cartilage, the tidemark, the layer of calcified cartilage, a thin cement line (between the calcified cartilage and the subchondral bone and the subchondral bone. A detailed knowledge of the structure, function and pathophysiology of the normal chondro-osseous junction is essential for an understanding of the pathogenesis of osteoarthrosis. Methods Full thickness samples from human knee joints were processed and embedded in paraffin wax. One hundred serial sections (10 μm thick were taken from the chondro-osseous junctional region of a block from the medial tibial plateau of a normal joint. They were stained with haematoxylin and eosin and photographed. For a simple physical reconstruction images of each 10th sequential tissue section were printed and the areas of the photomicrographs containing the chondro-osseous junctional region were cut out and then overlaid so as to create a three-dimensional (3D model of this region. A 3D reconstruction was also made using computer modelling. Results Histochemical staining revealed some instances where prolongations of uncalcified cartilage, delineated by the tidemark, dipped into the calcified cartilage and, in places, abutted onto subchondral bone and marrow spaces. Small areas of uncalcified cartilage containing chondrocytes (virtual islands were seen, in two-dimensional (2D sections, to be apparently entombed in calcified matrix. The simple physical 3D reconstruction confirmed that these prolongations of uncalcified cartilage were continuous with the cartilage of zone IV and demonstrated that the virtual islands of uncalcified cartilage were cross-sections of these prolongations. The computer-generated 3D reconstructions clearly demonstrated that the uncalcified prolongations ran through the calcified cartilage to touch bone and

  4. Morphological abnormalities in vitamin B6 deficient tarsometatarsal chick cartilage. (United States)

    Masse, P G; Colombo, V E; Gerber, F; Howell, D S; Weiser, H


    The aim of this study was to test the hypothesis that deficiency of vitamin B6 would produce morphological characteristics of osteochondral lathyrism. To accomplish this goal, morphological characteristics of chick cartilage in which lathyrism was produced by two separate dietary regimens was compared to morphological changes encountered in vitamin B6 deficiency. Vitamin B6 deficiency should reduce activity of lysyloxidase needed for producing intermolecular cross-links. The question to be addressed was: would this latter deficiency impair collagen morphological features and secondarily other structures indirectly by reducing collagen molecular assembly? Failure of cross-linking of collagen in the positive controls was related to a lack of functional aldehyde cross-link intermediates which are blocked by homocysteine and aminoacetonitrile. Day-old-male Lohmann chicks were fed adequate (6 mg/kg) or vitamin B6-deficient diets. Cross-link defects were induced by homocysteine-rich diets (0.6% w/w) or a diet containing aminoacetonitrile (0.1% w/w). Animals were sacrificed at 6 weeks of age and Ossa tarsalia articular cartilage specimens, as well as the proximal end of tarsometatarsus were dissected from the tibial metatarsal joint, a major weight-bearing site. Light microscopic observations revealed reduction of subarticular trabecular bone formation, concurrent with overexpansion of the hypertrophic cell zone. Ultrastructural electron microscopy observation of articular fibro-cartilage indicated significant thickening of collagen fibers in vitamin B6 deficient birds, as well as the positive controls in comparison to that of cage-matched control birds. It was concluded that vitamin B6 deficient cross-linking may be responsible for the observed delay in bone development and aforementioned cartilage histological alterations.

  5. A new injectable biphasic hydrogel based on partially hydrolyzed polyacrylamide and nano hydroxyapatite, crosslinked with chromium acetate, as scaffold for cartilage regeneration (United States)

    Koushki, N.; Tavassoli, H.; Katbab, A. A.; Katbab, P.; Bonakdar, S.


    Polymer scaffolds are applied in the field of tissue engineering as three dimensional structures to organize cells and present stimuli to direct generation of a desired damaged tissue. In situ gelling scaffolds have attracted great attentions, as they are structurally similar to the extra cellular matrix (ECM). In the present work, attempts have been made to design and fabricate a new injectable and crosslinkable biphasic hydrogel based on partially hydrolyzed polyacrylamide (HPAM), chromium acetate as crosslink agent and nanocrystalline hydroxyapatite (nHAp) as reinforcing and bioactive agent for repair and regeneration of damaged cartilage. The distinct characteristic of HPAM is the presence of carboxylate anion groups on its backbone which allows to engineer the structure of the hydrogel for the desired bioactivity with appropriate cells differentiation towards both soft and hard (bone) tissues. The synthesized hydrogel exhibited bifunctional behavior which was derived by its biphasic structure in which one phase was loaded with nano hydroxyapatite to provide integration capability by subchondral bones and fix the hydrogel at cartilage defect without a need for suturing. The other phase differentiates the rabbit adipogenic mesenchymal stem cells (MSCs) towards soft tissue. Rheomechanical spectrometry (RMS) was employed to study the kinetic of the gelation including induction time and rate, as well as to measure the ultimate elastic modulus of the optimum crosslinked hydrogel. Surface tension measurement was also performed to tailor the surface characteristics of the gels. In vitro culturing of the cells inside the crosslinked hydrogel revealed high viability and high differentiation of the encapsulated rabbit stem cells, providing that the chromium acetate level was kept below 0.2 wt%. Based on the obtained results, the designed and fabricated biphasic hydrogel exhibited high potential as carrier for the stem cells for cartilage tissue engineering application

  6. Adsorption of hydrogen sulfide onto activated carbon fibers: effect of pore structure and surface chemistry. (United States)

    Feng, Wenguo; Kwon, Seokjoon; Borguet, Eric; Vidic, Radisav


    To understand the nature of H2S adsorption onto carbon surfaces under dry and anoxic conditions, the effects of carbon pore structure and surface chemistry were studied using activated carbon fibers (ACFs) with different pore structures and surface areas. Surface pretreatments, including oxidation and heattreatment, were conducted before adsorption/desorption tests in a fixed-bed reactor. Raw ACFs with higher surface area showed greater adsorption and retention of sulfur, and heat treatment further enhanced adsorption and retention of sulfur. The retained amount of hydrogen sulfide correlated well with the amount of basic functional groups on the carbon surface, while the desorbed amount reflected the effect of pore structure. Temperature-programmed desorption (TPD) and thermal gravimetric analysis (TGA) showed that the retained sulfurous compounds were strongly bonded to the carbon surface. In addition, surface chemistry of the sorbent might determine the predominant form of adsorbate on the surface.

  7. PRP and Articular Cartilage: A Clinical Update

    National Research Council Canada - National Science Library

    Marmotti, Antonio; Rossi, Roberto; Castoldi, Filippo; Roveda, Eliana; Michielon, Gianni; Peretti, Giuseppe M


      The convincing background of the recent studies, investigating the different potentials of platelet-rich plasma, offers the clinician an appealing alternative for the treatment of cartilage lesions and osteoarthritis...

  8. Quantitative Imaging Biomarkers of Knee Cartilage Composition

    NARCIS (Netherlands)

    J. van Tiel (Jasper)


    markdownabstractFor a long time, radiography and subsequently conventional magnetic resonance imaging (MRI) were used as imaging biomarkers for evaluating cartilage morphological disease state in osteoarthritis (OA). Because research is switching its focus towards disease modification or even

  9. Cartilage Repair in Football (Soccer) Athletes (United States)

    Bekkers, J.E.J.; de Windt, Th.S.; Brittberg, M.


    The prevalence of focal articular cartilage lesions among athletes is higher than in the general population. Treatment goals differ considerably between the professional and recreational athlete. High financial stakes and the short duration of a professional career influence the treatment selection for the professional athlete, while such parameters weigh differently in recreational sports. This article describes our investigation of the relation between sports and a high prevalence of focal cartilage lesions. In addition, we provide a critical review of the best available evidence for cartilage surgery and treatment selection, evaluate specific patient profiles for professional and recreational athletes, and propose a treatment algorithm for the treatment of focal cartilage lesions in football (soccer) players. PMID:26069606

  10. Observations of Brine Pool Surface Characteristics and Internal Structure Through Remote Acoustic and Structured Light Imaging (United States)

    Smart, C.; Roman, C.; Michel, A.; Wankel, S. D.


    Observations and analysis of the surface characteristics and internal structure of deep-sea brine pools are currently limited to discrete in-situ observations. Complementary acoustic and structured light imaging sensors mounted on a remotely operated vehicle (ROV) have demonstrated the ability systematically detect variations in surface characteristics of a brine pool, reveal internal stratification and detect areas of active hydrocarbon activity. The presented visual and acoustic sensors combined with a stereo camera pair are mounted on the 4000m rated ROV Hercules (Ocean Exploration Trust). These three independent sensors operate simultaneously from a typical 3m altitude resulting in visual and bathymetric maps with sub-centimeter resolution. Applying this imaging technology to 2014 and 2015 brine pool surveys in the Gulf of Mexico revealed acoustic and visual anomalies due to the density changes inherent in the brine. Such distinct changes in acoustic impedance allowed the high frequency 1350KHz multibeam sonar to detect multiple interfaces. For instance, distinct acoustic reflections were observed at 3m and 5.5m below the vehicle. Subsequent verification using a CDT and lead line indicated the acoustic return from the brine surface was the signal at 3m, while a thicker muddy and more saline interface occurred at 5.5m, the bottom of the brine pool was not located but is assumed to be deeper than 15m. The multibeam is also capable of remotely detecting emitted gas bubbles within the brine pool, indicative of active hydrocarbon seeps. Bubbles associated with these seeps were not consistently visible above the brine while using the HD camera on the ROV. Additionally, while imaging the surface of brine pool the structured light sheet laser became diffuse, refracting across the main interface. Analysis of this refraction combined with varying acoustic returns allow for systematic and remote detection of the density, stratification and activity levels within and

  11. Medial meniscal posterior root/horn radial tears correlate with cartilage degeneration detected by T1ρ relaxation mapping

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Kenji, E-mail: [Department of Orthopaedic Surgery, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603 (Japan); Hashimoto, Sanshiro, E-mail: [Minami-Shinjuku Orthopaedic Rehabilitation Clinic, 2-16-7 Yoyogi, Shibuya-ku, Tokyo 151-0053 (Japan); Nakamura, Hiroshi, E-mail: [Department of Orthopaedic Surgery, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603 (Japan); Mori, Atsushi, E-mail: [Department of Orthopaedic Surgery, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603 (Japan); Sato, Akiko, E-mail: [Department of Orthopaedic Surgery, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603 (Japan); Majima, Tokifumi, E-mail: [Department of Orthopaedic Surgery, International University of Health and Welfare Hospital, 537-3 Iguchi, Nasu-shiobara, Tochigi 329-2763 (Japan); Takai, Shinro, E-mail: [Department of Orthopaedic Surgery, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603 (Japan)


    Highlights: • Posterior radial tears in medial meniscus associate T1ρ values of cartilage. • Posterior radial tears relate to cartilage degeneration even in early-stage osteoarthritis. • Abnormalities in meniscus on MRI are useful for screening early-stage osteoarthritis. - Abstract: Objective: This study aimed to identify factors on routine pulse sequence MRI associated with cartilage degeneration observed on T1ρ relaxation mapping. Materials and methods: This study included 137 subjects with knee pain. T1ρ values were measured in the regions of interest on the surface layer of the cartilage on mid-coronal images of the femorotibial joint. Assessment of cartilage, subchondral bone, meniscus and ligaments was performed using routine pulse sequence MRI. Radiographic evaluation for osteoarthritis was also performed. Results: Multiple regression analysis revealed posterior root/horn tears to be independent factors increasing the T1ρ values of the cartilage in the medial compartment of the femorotibial joint. Even when adjusted for radiographically defined early-stage osteoarthritis, medial posterior meniscal radial tears significantly increased the T1ρ values. Conclusions: This study showed that posterior root/horn radial tears in the medial meniscus are particularly important MRI findings associated with cartilage degeneration observed on T1ρ relaxation mapping. Morphological factors of the medial meniscus on MRI provide findings useful for screening early-stage osteoarthritis.

  12. Priming Adipose-Derived Mesenchymal Stem Cells with Hyaluronan Alters Growth Kinetics and Increases Attachment to Articular Cartilage

    Directory of Open Access Journals (Sweden)

    Peter Succar


    Full Text Available Background. Biological therapeutics such as adipose-derived mesenchymal stem cell (MSC therapy are gaining acceptance for knee-osteoarthritis (OA treatment. Reports of OA-patients show reductions in cartilage defects and regeneration of hyaline-like-cartilage with MSC-therapy. Suspending MSCs in hyaluronan commonly occurs in animals and humans, usually without supporting data. Objective. To elucidate the effects of different concentrations of hyaluronan on MSC growth kinetics. Methods. Using a range of hyaluronan concentrations, we measured MSC adherence and proliferation on culture plastic surfaces and a novel cartilage-adhesion assay. We employed time-course and dispersion imaging to assess MSC binding to cartilage. Cytokine profiling was also conducted on the MSC-secretome. Results. Hyaluronan had dose-dependent effects on growth kinetics of MSCs at concentrations of entanglement point (1 mg/mL. At higher concentrations, viscosity effects outweighed benefits of additional hyaluronan. The cartilage-adhesion assay highlighted for the first time that hyaluronan-primed MSCs increased cell attachment to cartilage whilst the presence of hyaluronan did not. Our time-course suggested patients undergoing MSC-therapy for OA could benefit from joint-immobilisation for up to 8 hours. Hyaluronan also greatly affected dispersion of MSCs on cartilage. Conclusion. Our results should be considered in future trials with MSC-therapy using hyaluronan as a vehicle, for the treatment of OA.

  13. miR-322 stabilizes MEK1 expression to inhibit RAF/MEK/ERK pathway activation in cartilage. (United States)

    Bluhm, Björn; Ehlen, Harald W A; Holzer, Tatjana; Georgieva, Veronika S; Heilig, Juliane; Pitzler, Lena; Etich, Julia; Bortecen, Toman; Frie, Christian; Probst, Kristina; Niehoff, Anja; Belluoccio, Daniele; Van den Bergen, Jocelyn; Brachvogel, Bent


    Cartilage originates from mesenchymal cell condensations that differentiate into chondrocytes of transient growth plate cartilage or permanent cartilage of the articular joint surface and trachea. MicroRNAs fine-tune the activation of entire signaling networks and thereby modulate complex cellular responses, but so far only limited data are available on miRNAs that regulate cartilage development. Here, we characterize a miRNA that promotes the biosynthesis of a key component in the RAF/MEK/ERK pathway in cartilage. Specifically, by transcriptome profiling we identified miR-322 to be upregulated during chondrocyte differentiation. Among the various miR-322 target genes in the RAF/MEK/ERK pathway, only Mek1 was identified as a regulated target in chondrocytes. Surprisingly, an increased concentration of miR-322 stabilizes Mek1 mRNA to raise protein levels and dampen ERK1/2 phosphorylation, while cartilage-specific inactivation of miR322 in mice linked the loss of miR-322 to decreased MEK1 levels and to increased RAF/MEK/ERK pathway activation. Such mice died perinatally due to tracheal growth restriction and respiratory failure. Hence, a single miRNA can stimulate the production of an inhibitory component of a central signaling pathway to impair cartilage development. © 2017. Published by The Company of Biologists Ltd.

  14. Surface structure determinations of crystalline ionic thin films grown on transition metal single crystal surfaces by low energy electron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Joel Glenn [Univ. of California, Berkeley, CA (United States)


    The surface structures of NaCl(100), LiF(100) and alpha-MgCl2(0001) adsorbed on various metal single crystals have been determined by low energy electron diffraction (LEED). Thin films of these salts were grown on metal substrates by exposing the heated metal surface to a molecular flux of salt emitted from a Knudsen cell. This method of investigating thin films of insulators (ionic salts) on a conducting substrate (metal) circumvents surface charging problems that plagued bulk studies, thereby allowing the use of electron-based techniques to characterize the surface.

  15. Bend loss in surface plasmon polariton band-gap structures

    DEFF Research Database (Denmark)

    Bozhevolnyi, S.I.; Volkov, V.S.; Leosson, Kristjan


    Using near-field optical microscopy, we investigate propagation of surface plasmon polaritons (SPPs) excited in the wavelength range of 720-830 nm at a corrugated gold-film surface with areas of 200-nm-wide and 45-nm-high scatterers arranged in a 410-nm-period triangular lattice containing line...

  16. Imprinted and injection-molded nano-structured optical surfaces

    DEFF Research Database (Denmark)

    Christiansen, Alexander Bruun; Højlund-Nielsen, Emil; Clausen, Jeppe Sandvik


    . In this paper, nanostructured polymer surfaces suitable for up-scalable polymer replication methods, such as imprinting/embossing and injection-molding, are discussed. The limiting case of injection-moulding compatible designs is investigated. Anti-reflective polymer surfaces are realized by replication...

  17. Assessment of Wind Turbine Structural Integrity using Response Surface Methodology

    DEFF Research Database (Denmark)

    Toft, Henrik Stensgaard; Svenningsen, Lasse; Moser, Wolfgang


    Highlights •A new approach to assessment of site specific wind turbine loads is proposed. •The approach can be applied in both fatigue and ultimate limit state. •Two different response surface methodologies have been investigated. •The model uncertainty introduced by the response surfaces...

  18. Materials science: Like cartilage, but simpler

    DEFF Research Database (Denmark)

    Skov, Anne Ladegaard


    The properties of articular cartilage, which lines bones in joints, depend partlyon repulsion between components of the material. A new synthetic gel that mimics this feature has rare, direction-dependent properties.......The properties of articular cartilage, which lines bones in joints, depend partlyon repulsion between components of the material. A new synthetic gel that mimics this feature has rare, direction-dependent properties....

  19. Animal Models for Cartilage Regeneration and Repair (United States)

    Szczodry, Michal; Bruno, Stephen


    Articular cartilage injury and degeneration are leading causes of disability. Animal studies are critically important to developing effective treatments for cartilage injuries. This review focuses on the use of animal models for the study of the repair and regeneration of focal cartilage defects. Animals commonly used in cartilage repair studies include murine, lapine, canine, caprine, porcine, and equine models. There are advantages and disadvantages to each model. Small animal rodent and lapine models are cost effective, easy to house, and useful for pilot and proof-of-concept studies. The availability of transgenic and knockout mice provide opportunities for mechanistic in vivo study. Athymic mice and rats are additionally useful for evaluating the cartilage repair potential of human cells and tissues. Their small joint size, thin cartilage, and greater potential for intrinsic healing than humans, however, limit the translational value of small animal models. Large animal models with thicker articular cartilage permit study of both partial thickness and full thickness chondral repair, as well as osteochondral repair. Joint size and cartilage thickness for canine, caprine, and mini-pig models remain significantly smaller than that of humans. The repair and regeneration of chondral and osteochondral defects of size and volume comparable to that of clinically significant human lesions can be reliably studied primarily in equine models. While larger animals may more closely approximate the human clinical situation, they carry greater logistical, financial, and ethical considerations. A multifactorial analysis of each animal model should be carried out when planning in vivo studies. Ultimately, the scientific goals of the study will be critical in determining the appropriate animal model. PMID:19831641

  20. 3D silicon breast surface mapping via structured light profilometry (United States)

    Vairavan, R.; Ong, N. R.; Sauli, Z.; Kirtsaeng, S.; Sakuntasathien, S.; Shahimin, M. M.; Alcain, J. B.; Lai, S. L.; Paitong, P.; Retnasamy, V.


    Digital fringe projection technique is one of the promising optical methods for 3D surface imaging as it demonstrates non contact and non invasive characteristics. The potential of this technique matches the requirement for human body evaluation, as it is vital for disease diagnosis and for treatment option selection. Thus, the digital fringe projection has addressed this requirement with its wide clinical related application and studies. However, the application of this technique for 3D surface mapping of the breast is very minimal. Hence, in this work, the application of digital fringe projection for 3D breast surface mapping is reported. Phase shift fringe projection technique was utilized to perform the 3D breast surface mapping. Maiden results have confirmed the feasibility of using the digital fringe projection method for 3D surface mapping of the breast and it can be extended for breast cancer detection.

  1. Effect of Surface Oxidation on Interfacial Water Structure at a Pyrite (100) Surface as Studied by Molecular Dynamics Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Jiaqi; Miller, Jan D.; Dang, Liem X.; Wick, Collin D.


    In the first part of this paper, a Scanning Electron Microscopy and contact angle study of a pyrite surface (100) is reported describing the relationship between surface oxidation and the hydrophilic surface state. In addition to these experimental results, the following simulated surface states were examined using Molecular Dynamics Simulation (MDS): fresh unoxidized (100) surface; polysulfide at the (100) surface; elemental sulfur at the (100) surface. Crystal structures for the polysulfide and elemental sulfur at the (100) surface were simulated using Density Functional Theory (DFT) quantum chemical calculations. The well known oxidation mechanism which involves formation of a metal deficient layer was also described with DFT. Our MDS results of the behavior of interfacial water at the fresh and oxidized pyrite (100) surfaces without/with the presence of ferric hydroxide include simulated contact angles, number density distribution for water, water dipole orientation, water residence time, and hydrogen-bonding considerations. The significance of the formation of ferric hydroxide islands in accounting for the corresponding hydrophilic surface state is revealed not only from experimental contact angle measurements but also from simulated contact angle measurements using MDS. The hydrophilic surface state developed at oxidized pyrite surfaces has been described by MDS, on which basis the surface state is explained based on interfacial water structure. The Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences (BES), of the DOE funded work performed by Liem X. Dang. Battelle operates the Pacific Northwest National Laboratory for DOE. The calculations were carried out using computer resources provided by BES.

  2. Mechanical characterization of articular cartilage by combining magnetic resonance imaging and finite-element analysis-a potential functional imaging technique

    Energy Technology Data Exchange (ETDEWEB)

    Julkunen, P; Korhonen, R K; Nissi, M J; Jurvelin, J S [Department of Physics, University of Kuopio, PO Box 1627, FI-70211 Kuopio (Finland)], E-mail:


    Magnetic resonance imaging (MRI) provides a method for non-invasive characterization of cartilage composition and structure. We aimed to see whether T{sub 1} and T{sub 2} relaxation times are related to proteoglycan (PG) and collagen-specific mechanical properties of articular cartilage. Specifically, we analyzed whether variations in the depthwise collagen orientation, as assessed by the laminae obtained from T{sub 2} profiles, affect the mechanical characteristics of cartilage. After MRI and unconfined compression tests of human and bovine patellar cartilage samples, fibril-reinforced poroviscoelastic finite-element models (FEM), with depthwise collagen orientations implemented from quantitative T{sub 2} maps (3 laminae for human, 3-7 laminae for bovine), were constructed to analyze the non-fibrillar matrix modulus (PG specific), fibril modulus (collagen specific) and permeability of the samples. In bovine cartilage, the non-fibrillar matrix modulus (R = -0.64, p < 0.05) as well as the initial permeability (R = 0.70, p < 0.05) correlated with T{sub 1}. In bovine cartilage, T{sub 2} correlated positively with the initial fibril modulus (R = 0.62, p = 0.05). In human cartilage, the initial fibril modulus correlated negatively (R = -0.61, p < 0.05) with T{sub 2}. Based on the simulations, cartilage with a complex collagen architecture (5 or 7 laminae), leading to high bulk T{sub 2} due to magic angle effects, provided higher compressive stiffness than tissue with a simple collagen architecture (3 laminae). Our results suggest that T{sub 1} reflects PG-specific mechanical properties of cartilage. High T{sub 2} is characteristic to soft cartilage with a classical collagen architecture. Contradictorily, high bulk T{sub 2} can also be found in stiff cartilage with a multilaminar collagen fibril network. By emerging MRI and FEM, the present study establishes a step toward functional imaging of articular cartilage.

  3. The comparison between the absorption rate of rib cartilage graft with conchal cartilage graft in rabbit

    Directory of Open Access Journals (Sweden)

    Soraya Shahrokh


    Full Text Available Background: Cartilage grafts is one integral component in the various fields of plastic surgery particular rhinoplasty. Surgeons usually use from various sources, including the septum of the nose, ears and rib. Complications such deformity and reabsorbtion may be created with use of the cartilage. Area of the removal of cartilage can prevent these complications. The aim of this study was to compare the absorption rate and viability of cartilage autograft between two common donor site, the rib and the concha. Methods: This experimental study was performed on October 2014 in animal laboratory of Hazrat Fatima Hospital, Tehran, Iran. In this study, 15 New Zealand white male rabbits, weighing 2000-2500 g, approximately 12 to 16 weeks of age were used. In each rabbit, a piece of one ear and one cartilage was excised. After careful weighting of grafts, we implanted the rib cartilage graft into the left pocket and the conchal cartilage graft into the right one. After 8 weeks, the grafts were removed and weighed precisely and photography was carried out. The specimens were fixed in 10% formalin solution for histologic examination was. An example of hematoxylin and eosin staining and cut (H&E were performed and samples of live chondrocytes and fibrosis were examined by a pathologist. Results: We lost 3 rabbits during our study. The results showed that the average weight of a graft from the ear within 2 months, but this increase was not statistically significant (P= 0.152. In the rib graft weight loss over 2 months, and this reduction was statistically significant (P= 0.009. The resorption between two group was not significant but the amount of fibrosis was more in conchal cartilage graft. Conclusion: According to the study it can be concluded that absorption rib cartilage is somewhat better results than the cartilage of the ear. More studies, in addition to cartilage implants longer human studies can contribute to more accurate conclusions.

  4. Inorganic polyphosphate stimulates cartilage tissue formation. (United States)

    St-Pierre, Jean-Philippe; Wang, Qishan; Li, Shu Qiu; Pilliar, Robert M; Kandel, Rita A


    Clinical utilization of tissue-engineered cartilage constructs has been limited by their inferior mechanical properties compared to native articular cartilage. A number of strategies have been investigated to increase the accumulation of major extracellular matrix components within in vitro-formed cartilage, including the administration of growth factors and mechanical stimulation. In this study, the anabolic effect of inorganic polyphosphates, a linear polymer of orthophosphate residues linked by phosphoanhydride bonds, was demonstrated in both chondrocyte cultures and native articular cartilage cultured ex