50 research outputs found
Approximation to the application of the Bougard process on the ceramics of Dolni Vestonice I
Full text linkEste trabajo recoge la propuesta que realiza Bougard en su trabajo de 2011 sobre la forma
de producción de las figuras cerámicas que se encuentran en el yacimiento checo de Dolni
Vestonice I, cuya cronología se encuadra en el Gravetiense de Europa Central y la
importancia técnica del trato de la arcilla en una etapa del Paleolítico Superior con pocos
ejemplos parecidos. La configuración de la experimentación se realizará en el Laboratorio
Experimental de la Universidad Autónoma y con materiales de la Península IbéricaThis work reflects the proposal made by Bougard in his work in 2011 on the form of
production of the ceramic figures found in the Czech deposit of Dolni Vestonice I, whose
chronology is in the Gravetian of Central Europe and the technical importance of the
treatment Of the clay in a stage of the Upper Paleolithic with few similar examples. The
configuration of the experimentation will be carried out in the Experimental Laboratory
of the UAM and with materials of the Iberian Peninsul
Regional Mechanical Properties and Regeneration of the Mandibular Condylar Cartilage
Get PDFThe temporomandibular joint (TMJ) is one of the most complex articulating joints in the body. In addition, the surface of the condyle is mandibular condylar cartilage (MCC), which consists of different populations of cells within each of its layers. Damage or displacement to the disc and other abnormalities of the jaw can lead to eventual degeneration of the MCC. If downstream degeneration of the cartilage continues to progress, the avascular nature of the joint renders the tissue unable to regenerate on its own.
Prior studies have attempted regeneration of the mandibular condyle with limited success. Regional viscoelastic properties of the MCC are also not well characterized, making the target of regeneration therapies unclear for this tissue. This dissertation aims to elucidate the regional mechanical properties, and providing a tissue engineering alternative through the use of soft biomaterials for the MCC.
First, the regional compressive properties of the porcine TMJ disc and MCC were evaluated through the use of the transversely isotropic biphasic theory. Mechanical and viscoelastic properties of the five different regions of these tissues were evaluated and compared with one another. The results demonstrated higher compressive properties in the posterior region of the disc and also estimated the moduli in different planes, the Poisson’s ratio, and permeability of the MCC. Next, the focus shifted to determining the efficacy of using various soft biomaterials for the mandibular condyle regeneration of an osteochondral defect in the goat model. Acellular polyglycol sebacate and gelatin sponge scaffolds demonstrated cartilage regeneration with presence of collagen II and glycosaminoglycans after 3 months of healing. In hopes of using a cell-laden therapy, in vitro studies with BMSCs and also native cells of the mandibular condyle were conducted. Gelatin hydrogels supported differentiation of BMSCs towards a cartilage lineage, and a gelatin hydrogel composite supported chondrogenesis, and inhibited both mineralization and chondrocyte hypertrophy. Compressive properties of the in vitro scaffolds were also comparable to the measured values of the native MCC. The results of this dissertation give rise to an understanding of the viscoelastic properties of the MCC and give insight on promising soft biomaterials
A Comparison of the Mechanical Properties of the Goat Temporomandibular Joint Disc to the Mandibular Condylar Cartilage in Unconfined Compression
Get PDFThe aim of this study was to make a comparison of the compressive properties of the goat temporomandibular joint (TMJ) disc to the mandibular condylar cartilage (MCC) and to explore the transversely isotropic biphasic model. Samples taken mediolaterally from three regions of the TMJ disc and MCC were tested in unconfined compression at strain levels ranging from 10% to 50% and then assessed for biochemical content. The results indicated that the TMJ disc exhibits a significantly greater tangent modulus than the MCC from 20% to 50% strain with values ranging from 729 ± 267 to 2413 ± 406 kPa and 363 ± 169 to 1677 ± 538 kPa, respectively (P < .05). The collagen content of the TMJ disc was significantly greater than the MCC, while the opposite held for the glycosaminoglycan (GAG) and DNA content. The results emphasize fundamental differences between the articulating tissues of the TMJ
Propuesta para el rediseño de sistemas de aspiración por extracción localizada
Get PDFEl presente trabajo desarrolla un método enfocado en establecer una guía de diagnóstico para una posterior etapa de diseño. La metodología se enfoca en sistemas de extracción de diámetro progresivo que disponen de separadores de tejido como elementos de filtración. La labor de “rediseñar” puede presentar mayores incertidumbres que un nuevo prototipo dada la variedad de factores derivados de utilizar herramientas ya existentes; en muchos casos, inclusive actualmente instaladas y ya en operación. Con el objetivo de plantear directrices que encaminen el análisis integral e individual de los componentes, se presenta una estructura para un proceso ordenado y claro soportado en una base de cálculo que considera a cada uno de los componentes. De esta forma se combinan elementos cuantitativos y cualitativos de diseño para un análisis detallado. Asimismo, se considera un método gráfico para los cálculos de caída de presión como instrumento de análisis del sistema en el tiempo
Patient-Specific Prosthetic Fingers by Remote Collaboration - A Case Study
Get PDFThe concealment of amputation through prosthesis usage can shield an amputee
from social stigma and help improve the emotional healing process especially at
the early stages of hand or finger loss. However, the traditional techniques in
prosthesis fabrication defy this as the patients need numerous visits to the
clinics for measurements, fitting and follow-ups. This paper presents a method
for constructing a prosthetic finger through online collaboration with the
designer. The main input from the amputee comes from the Computer Tomography
(CT) data in the region of the affected and the non-affected fingers. These
data are sent over the internet and the prosthesis is constructed using
visualization, computer-aided design and manufacturing tools. The finished
product is then shipped to the patient. A case study with a single patient
having an amputated ring finger at the proximal interphalangeal joint shows
that the proposed method has a potential to address the patient's psychosocial
concerns and minimize the exposure of the finger loss to the public.Comment: Open Access articl
Comparison of Two Methods for In Vivo Estimation of the Glenohumeral Joint Rotation Center (GH-JRC) of the Patients with Shoulder Hemiarthroplasty
Get PDFDetermination of an accurate glenohumeral-joint rotation center (GH-JRC) from marker data is essential for kinematic and dynamic analysis of shoulder motions. Previous studies have focused on the evaluation of the different functional methods for the estimation of the GH-JRC for healthy subjects. The goal of this paper is to compare two widely used functional methods, namely the instantaneous helical axis (IHA) and symmetrical center of rotation (SCoRE) methods, for estimating the GH-JRC in vivo for patients with implanted shoulder hemiarthroplasty. The motion data of five patients were recorded while performing three different dynamic motions (circumduction, abduction, and forward flexion). The GH-JRC was determined using the CT-images of the subjects (geometric GH-JRC) and was also estimated using the two IHA and SCoRE methods. The rotation centers determined using the IHA and SCoRE methods were on average 1.47±0.62 cm and 2.07±0.55 cm away from geometric GH-JRC, respectively. The two methods differed significantly (two-tailed p-value from paired t-Test ∼0.02, post-hoc power ∼0.30). The SCoRE method showed a significant lower (two-tailed p-value from paired t-Test ∼0.03, post-hoc power ∼0.68) repeatability error calculated between the different trials of each motion and each subject and averaged across all measured subjects (0.62±0.10 cm for IHA vs. 0.43±0.12 cm for SCoRE). It is concluded that the SCoRE appeared to be a more repeatable method whereas the IHA method resulted in a more accurate estimation of the GH-JRC for patients with endoprostheses
The morphometry of soft tissue insertions on the tibial plateau: Data acquisition and statistical shape analysis
Get PDFThis study characterized the soft tissue insertion morphometrics on the tibial plateau and their inter-relationships as well as variabilities. The outlines of the cruciate ligament and meniscal root insertions along with the medial and lateral cartilage on 20 cadaveric tibias (10 left and 10 right knees) were digitized and co-registered with corresponding CT-based 3D bone models. Generalized Procrustes Analysis was employed in conjunction with Principal Components Analysis to first create a geometric consensus based on tibial cartilage and then determine the means and variations of insertion morphometrics including shape, size, location, and inter-relationship measures. Step-wise regression analysis was conducted in search of parsimonious models relating the morphometric measures to the tibial plateau width and depth, and basic anthropometric and gender factors. The analyses resulted in statistical morphometric representations for Procrustes-superimposed cruciate ligament and meniscus insertions, and identified only a few moderate correlations (R 2: 0.37-0.49). The study provided evidence challenging the isometric scaling based on a single dimension frequently employed in related morphometric studies, and data for evaluating cruciate ligament reconstruction strategies in terms of re-creating the native anatomy and minimizing the risk of iatrogenic injury. It paved the way for future development of computer-aided personalized orthopaedic surgery applications improving the quality of care and patient safety, and biomechanical models with a better population or average representation
Control of Cell Migration and Inflammatory Mediators Production by CORM-2 in Osteoarthritic Synoviocytes
Get PDFBackgroundOsteoarthritis (OA) is the most widespread degenerative joint disease. Inflamed synovial cells contribute to the release of inflammatory and catabolic mediators during OA leading to destruction of articular tissues. We have shown previously that CO-releasing molecules exert anti-inflammatory effects in animal models and OA chondrocytes. We have studied the ability of CORM-2 to modify the migration of human OA synoviocytes and the production of chemokines and other mediators sustaining inflammatory and catabolic processes in the OA joint.Methodology/Principal FindingsOA synoviocytes were stimulated with interleukin(IL)-1β in the absence or presence of CORM-2. Migration assay was performed using transwell chambers. Gene expression was analyzed by quantitative PCR and protein expression by Western Blot and ELISA. CORM-2 reduced the proliferation and migration of OA synoviocytes, the expression of IL-8, CCL2, CCL20, matrix metalloproteinase(MMP)-1 and MMP-3, and the production of oxidative stress. We found that CORM-2 reduced the phosphorylation of extracellular signal-regulated kinase1/2, c-Jun N-terminal kinase1/2 and to a lesser extent p38. Our results also showed that CORM-2 significantly decreased the activation of nuclear factor-κB and activator protein-1 regulating the transcription of chemokines and MMPs in OA synoviocytes.Conclusion/SignificanceA number of synoviocyte functions relevant in OA synovitis and articular degradation can be down-regulated by CORM-2. These results support the interest of this class of agents for the development of novel therapeutic strategies in inflammatory and degenerative conditions
Elastogenic Protein Expression of a Highly Elastic Murine Spinal Ligament: The Ligamentum Flavum
Get PDFSpinal ligaments, such as the ligamentum flavum (LF), are prone to degeneration and iatrogenic injury that can lead to back pain and nerve dysfunction. Repair and regeneration strategies for these tissues are lacking, perhaps due to limited understanding of spinal ligament formation, the elaboration of its elastic fibers, maturation and homeostasis. Using immunohistochemistry and histology, we investigated murine LF elastogenesis and tissue formation from embryonic to mature postnatal stages. We characterized the spatiotemporal distribution of the key elastogenic proteins tropoelastin, fibrillin-1, fibulin-4 and lysyl oxidase. We found that elastogenesis begins in utero with the microfibril constituent fibrillin-1 staining intensely just before birth. Elastic fibers were first detected histologically at postnatal day (P) 7, the earliest stage at which tropoelastin and fibulin-4 stained intensely. From P7 to P28, elastic fibers grew in diameter and became straighter along the axis. The growth of elastic fibers coincided with intense staining of tropoelastin and fibulin-4 staining, possibly supporting a chaperone role for fibulin-4. These expression patterns correlated with reported skeletal and behavioral changes during murine development. This immunohistochemical characterization of elastogenesis of the LF will be useful for future studies investigating mechanisms for elastogenesis and developing new strategies for treatment or regeneration of spinal ligaments and other highly elastic tissues
Increased Risk of Temporomandibular Joint Closed Lock: A Case-Control Study of ANKH Polymorphisms
Get PDFObjectives: This study aimed to carry out a histological examination of the temporomandibular joint (TMJ) in ank mutant mice and to identify polymorphisms of the human ANKH gene in order to establish the relationship between the type of temporomandibular disorders (TMD) and ANKH polymorphisms.\ud
\ud
Materials and Methods: Specimens from the TMJ of ank mutant and wild-type mice were inspected with a haematoxylin and eosin staining method. A sample of 55 TMD patients were selected. Each was examined with standard clinical procedures and genotyping techniques.\ud
\ud
Results: The major histological finding in ank mutant mice was joint space narrowing. Within TMD patients, closed lock was more prevalent among ANKH-OR homozygotes (p = 0.011, OR = 7.7, 95% CI 1.6–36.5) and the elder (p = 0.005, OR = 2.4, 95% CI 1.3–4.3).\ud
\ud
Conclusions: Fibrous ankylosis was identified in the TMJ of ank mutant mice. In the human sample, ANKH-OR polymorphism was found to be a genetic marker associated with TMJ closed lock. Future investigations correlating genetic polymorphism to TMD are indicated
