Generation of a Biomimetic Substitute of the Corneal Limbus Using Decellularized Scaffolds

Patients with severe limbal damage and limbal stem cell deficiency are a therapeutic challenge. We evaluated four decellularization protocols applied to the full-thickness and half-thickness porcine limbus, and we used two cell types to recellularize the decellularized limbi. The results demonstrated that all protocols achieved efficient decellularization. However, the method that best preserved the transparency and composition of the limbus extracellular matrix was the use of 0.1% SDS applied to the half-thickness limbus. Recellularization with the limbal epithelial cell line SIRC and human adipose-derived mesenchymal stem cells (hADSCs) was able to generate a stratified epithelium able to express the limbal markers p63, pancytokeratin, and crystallin Z from day 7 in the case of SIRC and after 14–21 days of induction when hADSCs were used. Laminin and collagen IV expression was detected at the basal lamina of both cell types at days 14 and 21 of follow-up. Compared with control native limbi, tissues recellularized with SIRC showed adequate picrosirius red and alcian blue staining intensity, whereas limbi containing hADSCs showed normal collagen staining intensity. These preliminary results suggested that the limbal substitutes generated in this work share important similarities with the native limbus and could be potentially useful in the future.

OPTIMIZATION OF THE KNIFE PROFILE SHAPE FOR RESOURCE-SAVING PRIMARY FISH PROCESSING

Показана актуальность оптимизации формы профиля ножа для ресурсосберегающего резания рыбы. Мышечная ткань сырья описана реологической моделью МаксвеллаТомсона. Для описания формы криволинейных передних граней использован многочлен третьей степени. Путем решения дифференциального уравнения состояния вязкоупругого материала получены выражения для размерной и безразмерной сил сопротивления при резании рыбы. В результате решения оптимизационной задачи получено выражение для оптимального половинного угла заточки, с которым нож испытывает минимальное вредное сопротивление. Исследованы зависимости безразмерной силы сопротивления формы от геометрических параметров фаски режущего органа. Установлены зависимости оптимального половинного угла заточки бZ1 от безразмерной скорости резания, угла сопряжения, безразмерной половинной толщины ножа и меры эластичности рыбы e01. Оптимальный угол бZ1 зависит от безразмерной половинной толщины ножа , угла сопряжения и безразмерной скорости. Определено, что при резании рыбы ножом с минимальным углом сопряжения граней оптимальный половинный угол заточки составляет 1725 градусов. The relevance of knife profile shape optimization for resource-saving fish cutting has been shown. The muscle tissue of the raw material has been described by the MaxwellThomson rheological model. To describe the shape of the curved front edges, a polynomial of the third degree has been used. Expressions for dimensional and dimensionless resistance forces during cutting fish were obtained by solving the differential equation of state of a viscoelastic material. As a result of solving the optimization problem, an expression for the optimal half sharpening angle with which the knife experiences minimal harmful resistance has been obtained. The dependences of the dimensionless shape resistance force on the geometric parameters of the chamfer of the cutting tool have been investigated. The dependences of the optimal half sharpening angle бZ1 on the dimensionless cutting speed, the mating angle, the dimensionless half knife thickness д and the measure of fish elasticity e01 have been established. The indicated optimal angle бZ1 substantially depends on the dimensionless half thickness of the knife, the mating angle, and dimensionless speed. It was determined that when cutting fish with a knife with a minimum angle of mating of the edges, the optimal half sharpening angle is in the range of 1725 degrees.

Calculation of Shielding Parameters of Fast Neutrons for Some Composite Materials

In this paper ,Shielding parameters of fast neutrons like removal cross section , half thickness , and mean free path were calculated for polymer composite whish consisted of paraffin wax as basic material (P) with various reinforced materials (B, B2O3, Fe2O3, W, Clay) with different reinforced concentration (5, 15, 25, 35, 45) % . Results have been shown that , with increasing the reinforced materials concentrations , removal cross section increases while half thickness and mean free path decreased.

Effect of wood species, adhesive type, and annual ring directions on the stiffness of rail to leg mortise and tenon furniture joints

The effects of selected factors, wood species (Fagus sylvatica L. and Picea abies L.), type of joint (haunched mortise and tenon, and haunched dovetail mortise and tenon), tenon thickness (one-third and half-joint thickness), type of adhesive (polyvinyl acetate and polyurethane adhesive), loading type (compressive and tensile), and direction of the annual rings were evaluated relative to the elastic stiffness. The testing samples were loaded by bending moment with tensile and compressive forces in the angular plane. The wood species, type of joint, tenon dimension, and type of adhesive all had a statistically significant effect on the elastic stiffness. However, the interaction of those factors was statistically insignificant. The loading type and direction of the annual rings did not have a significant effect on the elastic stiffness. For spruce, the use of mortise and tenon with a toothed feather (MTTF) was found to be disadvantageous, whereas the use of a toothed feather was favorable for beech. Half thickness of the joint was always an advantage, such that the stiffness increased. For spruce joints, the type of glue was not important, whereas for beech, the stiffness of joints glued with PVAc was significantly higher than with PUR adhesive.

Initiation of a major calving event on the Bowdoin Glacier captured by UAV photogrammetry

In this paper, we analyse the calving activity of the Bowdoin Glacier, north-western Greenland, in 2015 by combining satellite images, UAV (unmanned aerial vehicle) photogrammetry and ice flow modelling. In particular, a high-resolution displacement field is inferred from UAV orthoimages taken immediately before and after the initiation of a large fracture, which induced a major calving event. A detailed analysis of the strain rate field allows us to accurately map the path taken by the opening crack. Modelling results reveal (i) that the crack was more than half-thickness deep, filled with water and getting irreversibly deeper when it was captured by the UAV and (ii) that the crack initiated in an area of high horizontal shear caused by a local basal bump immediately behind the current calving front. The asymmetry of the bed at the front explains the systematic calving pattern observed in May and July–August 2015. As a corollary, we infer that the calving front of the Bowdoin Glacier is currently stabilized by this bedrock bump and might enter into an unstable mode and retreat rapidly if the glacier keeps thinning in the coming years. Beyond this outcome, our study demonstrates that the combination of UAV photogrammetry and ice flow modelling is a promising tool to horizontally and vertically track the propagation of fractures responsible for large calving events.

Tibialis Anterior Tendon Reconstruction Using Augmented Half-Thickness Tendon Segment Transposition

Tibialis anterior tendon rupture causes substantial morbidity. The present study describes the outcomes of augmented, half-thickness tibialis anterior tendon segment transposition, a novel reconstruction technique. This was an institutional review board–approved retrospective review of 3 patients with surgically treated attritional distal rupture with 1-year follow-up. The postdebridement tendon defect prohibited primary repair and was managed by distal transposition of a half-thickness healthy segment. This repair was augmented with human acellular dermal matrix allograft (Graftjacket, Wright Medical Technology, Memphis, TN). The mean age was 68 years (range, 59-73 years). Mean interval between injury and surgery was 59.3 days (range, 15-146 days). All patients regained symmetrical range of motion, motor power, and the ability to heel walk. Mean pain scores improved from 4.6 (range, 2.5-8.5) preoperatively to 0.7 (range, 0-2) postoperatively. Mean Foot and Ankle Ability Measure scores increased from 30.6 (range, 23.8-43.8) preoperatively to 78.7 (range, 72.6-97.6) postoperatively. No postoperative complications occurred. One patient was satisfied and 2 were very satisfied with their outcome. Although limited, the present findings appear to indicate that this technique produces short-term clinical results comparable to those described for other techniques for tibialis anterior tendon reconstruction. Levels of Evidence: Therapeutic, Level IV

Initiation of a major calving event on Bowdoin Glacier captured by UAV photogrammetry

In this paper, we analyse the calving activity of Bowdoin Glacier, north-west Greenland, in 2015 by combining satellite images, UAV (Unmanned Aerial Vehicles) photogrammetry and ice flow modelling. In particular, a high-resolution displacement field is inferred from UAV orthoimages taken immediately before and after the initiation of a large fracture, which induced a major calving event. A detailed analysis of the strain rate field allows us to map accurately the path taken by the opening crack. Modelling results reveal i) that the crack was more than half-thickness deep, filled with water, and getting irreversibly deeper when it was captured by the UAV and ii) that the crack initiated in an area of high horizontal shear caused by a local basal bump immediately behind the current calving front. The asymmetry of the bed at the front explains the systematic calving pattern observed in May and July–August 2015. As a corollary, we infer that the calving front of Bowdoin Glacier is currently stabilized by this bedrock bump and might enter in an unstable mode and retreat rapidly if the glacier keeps thinning in the coming years. Beyond this outcome, our study demonstrates that the combination of UAV photogrammetry and ice flow modelling is a promising tool to track horizontally and vertically the propagation of fractures responsible for large calving events.