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

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

Fibrin glue improves osteochondral scaffold fixation: study on the human cadaveric knee exposed to continuous passive motion

SummaryObjectiveTo evaluate stability and integrity of bi-layer and three-layer collagen-hydroxyapatite (C-HA) osteochondral scaffolds in a human cadaveric knee exposed to continuous passive motion (CPM) with and without loading and the role of added fibrin glue to improve the press-fit fixation of C-HA scaffolds.DesignOsteochondral lesions (2.0 × 1.5 cm) were chiseled out on both condyles and trochlea in eight human cadaveric knees. A total of 24 bi-layer (5 mm, four in each condyle) or three-layer C-HA scaffolds (8 mm, eight in the trochlea, four in each condyle) were first press-fit implanted and underwent testing with CPM, 90 cycles, 0°–90°. The second set of 24 scaffolds was implanted in cleaned lesions with the addition of fibrin glue. Two knees with fibrin glue fixation were additionally exposed to 15 kg loading, with 30 cycles of CPM, 0°–30°. Then, the knees were reopened and the scaffolds were evaluated using semi-quantitative Drobnic and modified Bekkers scores.ResultsAll but two scaffolds remained in the lesions site throughout CPM. Two implants failed: both were bi-layer osteochondral scaffolds, press-fit implanted at the lateral femoral condyle (LFC). A statistically significant difference was obtained between press-fit and fibrin glue implants with both Drobnic (2.9 ± 0.7 vs 4.3 ± 0.1, P < 0.0005) and Bekkers (3.3 ± 1.0 vs 5.0 ± 0.1, P < 0.0005) scores. Additional knee loading did not affect fibrin glue scaffold fixation or integrity.ConclusionThis cadaveric study showed fibrin glue notably improved bi-layer or three-layer C-HA scaffold press-fit fixation regardless of lesion location. It is therefore recommended that fibrin glue be used during surgery to improve early post-operative C-HA scaffold stability and integrity

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

A Risk-Based Methodology and Tool Combining Threat Analysis and Power System Security Assessment

A thorough investigation of power system security requires the analysis of the vulnerabilities to natural and man-related threats which potentially trigger multiple contingencies. In particular, extreme weather events are becoming more and more frequent due to climate changes and often cause large load disruptions on the system, thus the support for security enhancement gets tricky. Exploiting data coming from forecasting systems in a security assessment environment can help assess the risk of operating power systems subject to the disturbances provoked by the weather event itself. In this context, the paper proposes a security assessment methodology, based on an updated definition of risk suitable for power system risk evaluations. Big data analytics can be useful to get an accurate model for weather-related threats. The relevant software (SW) platform integrates the security assessment methodology with prediction systems which provide short term forecasts of the threats affecting the system. The application results on a real wet snow threat scenario in the Italian High Voltage grid demonstrate the effectiveness of the proposed approach with respect to conventional security approaches, by complementing the conventional "N - 1" security criterion and exploiting big data to link the security assessment phase to the analysis of incumbent threat

INFLUENCE OF AGE AND HAND GRIP STRENGTH ON FREESTYLE PERFORMANCES IN MASTER SWIMMERS

The aim of our work was to examine whether age and hand grip strength are correlated with 50m, 100m, 200m, 400m, 800m swimming performance times in Master swimmers and how correlation varies considering short, middle or long distances. The main finding of this work was that hand grip strength and age correlated significantly at each distance. Hand grip strength showed a relevant influence on performance time and explained 52% of variance of performance time in 50m race freestyle and only 15% in 800m race. Increasing age was a disadvantageous factor for performance time, and explained 45% of variance of performance time in 800m race freestyle and only 20% in 50 m race