Influence of Living Plant Roots and Mycorrhizal Hyphae on Soil Hydraulic Properties

The interrelationships between vegetation, soil, and water are fundamental in evaluating the projected impacts of global climate change. Many predictive models require soil hydraulic parameters as inputs. As most hydraulic parameter datasets are for repacked soil, the influence of vegetation on hydraulic parameters is not thoroughly understood. Living roots and mycorrhizal fungi cause physicochemical alterations in soils. Quantifying how vegetation influences soil hydraulic parameters is necessary to more accurately simulate soil water dynamics in climate models. Laboratory experiments were conducted to test if the presence of roots and roots inoculated with mycorrhizal fungi have a significant effect on the saturated and unsaturated hydraulic conductivity, and water retention properties of two soils with contrasting textures: Flint sand and Hamblen silt loam soil. Cores were seeded with Switchgrass (Panicum virgatum) and grown in a greenhouse over three separate growth periods. Serendipita indica was injected as liquid inoculant into designated mycorrhizal cores. In both soil types, the presence of roots with mycorrhizal fungi increased total biomass. Saturated hydraulic conductivity measurements were obtained with a soil permeameter using the constant head method. Analysis of variance (ANOVA) found that saturated hydraulic conductivity was reduced (due to pore clogging) by the presence of plant roots when grown under nutrient-deficient conditions in comparison to bare soil. In contrast, no significant differences were found between treatments for unsaturated hydraulic conductivity curve parameters obtained using the evaporation method. Soil water retention curves were also obtained using the evaporation method, and supplemented at the dry end for the Hamblen silt loam by water activity meter data. Retention curve parameters were obtained by fitting the van Genuchten equation to the resulting measurements. ANOVA indicated the presence of roots changed the shape of the water retention curve in two ways: (i) by increasing water content at saturation, and (ii) and by reducing the slope of the curve. These changes suggested roots created additional porosity and broadened the pore size distribution. The presence of mycorrhizal fungi further accentuated these effects. Future research should investigate the effect of root-mycorrhizal interactions on soil hydraulic parameters for more soil types, plant-fungal associates, and time periods

Tissue engineering for total meniscal substitution : Animal study in sheep model

Objective: The aim of the study was to investigate the use of a novel hyaluronic acid/polycaprolactone material for meniscal tissue engineering and to evaluate the tissue regeneration after the augmentation of the implant with expanded autologous chondrocytes. Two different surgical implantation techniques in a sheep model were evaluated. Methods: Twenty-four skeletally mature sheep were treated with total medial meniscus replacements, while two meniscectomies served as empty controls. The animals were divided into two groups: cell-free scaffold and scaffold seeded with autologous chondrocytes. Two different surgical techniques were compared: in 12 animals, the implant was sutured to the capsule and to the meniscal ligament; in the other 12 animals, also a transtibial fixation of the horns was used. The animals were euthanized after 4 months. The specimens were assessed by gross inspection and histology. Results: All implants showed excellent capsular ingrowth at the periphery. Macroscopically, no difference was observed between cell-seeded and cell-free groups. Better implant appearance and integrity was observed in the group without transosseous horns fixation. Using the latter implantation technique, lower joint degeneration was observed in the cell-seeded group with respect to cell-free implants. The histological analysis indicated cellular infiltration and vascularization throughout the implanted constructs. Cartilaginous tissue formation was significantly more frequent in the cell-seeded constructs. Conclusion: The current study supports the potential of a novel HYAFF/polycaprolactone scaffold for total meniscal substitution. Seeding of the scaffolds with autologous chondrocytes provides some benefit in the extent of fibrocartilaginous tissue repair

Novel nano-composite multi-layered biomaterial for the treatment of multifocal degenerative cartilage lesions

We report on a 46-year-old athletic patient, previously treated with anterior cruciate ligament reconstruction, with large degenerative chondral lesions of the medial femoral condyle, trochlea and patella, which was successfully treated with a closing-wedge high tibial osteotomy and the implant of a newly developed biomimetic nanostructured osteochondral bioactive scaffold. After 1 year of follow-up the patient was pain-free, had full knee range of motion, and had returned to his pre-operation level of athletic activity. MRI evaluation at 6 months showed that the implant gave a hyaline-like signal as well as a good restoration of the articular surface, with minimal subchondral bone oedema. Subchondral oedema was almost non-visible at 12 months

A NEW METHOD FOR EVALUATION OF THE CARRYING ANGLE IN-VIVO SET UP

The "carrying angle" is defined as the angle formed by the long axis of the humerus and the long axis of the ulna(1.2J. This angle was measured in-vitro by several methodsl1j but few authors accomplished this measurements in vivo [2J probably due to the difficulties related to the identification of repere points. The goal of this work was to define an easy, fast and accurate new method for evaluation of the carrying angle in an in-vivo set up usable in rehabilitation and sport fields. In this work we present the method, analyse its repeatability and we compare the results with measures performed using a goniometer

A PRELIMINARY STUDY TO MODEL CARRYING ANGLE VARIATIONS DURING FLEXION-EXTENSION OF THE ELBOW

The aim of this work was to identify an accurate method to evaluate the variability of the carrying angle during the flexion extension of the elbow and to define a mathematical description of this movement applicable in sport and rehabilitation field. In order to develop this objective, we marked the arm and the forearm by six reflective markers of six healthy subjects performing the flexion extension movement and acquired the coordinates using six infrared cameras (VICON Motion System). Five repeated measures were performed for each subject in order to verify the reliability of the measures. Our results demonstrated that this movement can be easily modelled as a linear variation of the carrying angle in function of the flexion angle. The reliability between repeated measures was high and adopting a linear fit the accuracy was more than 94% in all cases. This is the first study to compute the flexion-extension movement by a carrying angle evaluation

EQUATION REGRESSION MODEL FOR THE 50 M FREESTYLE PERFORMANCE IN ELITE MASTER SWIMMERS

This study was conducted during the 10th World Masters Championships, held in Riccione, Italy, June 3-11, 2004. The aim was to investigate, in male and female elite master swimmers, the relationships between performance time and age, anthropometric characteristics (weight, stature, arm and forearm lengths and forearm volume) and muscle strength (hand grip). Performance times were recorded during 50 m freestyle events. Anthropometric values and hand grip were collected the same day the competition in a field laboratory organised beside the swimming pool. For this study we considered twenty eight volunteers: 15 men aged 42-81 years and 13 women aged 4173 years. Firstly, the anthropometrical characteristics. the hand grip strength and the performance time were used for a simple correlation analysis. Subsequently a multiple regression analysis was carried out to create a swimming time prediction model for the 50 freestyle performances. It revealed that in 50 m freestyle women race, age, weight and strength explained about 97% of the variance in performance. This study provided novel information which could be useful in designing training programs, optimizing swimmer's resources or capabilities