The addition of p-perfluoro-ethylbenzoic acid as capping reagent yields stable size-selected MOF-5 colloids and suggests a general concept for controlled particle formation of carboxylic acid based MOFs in solution.

SUMMARY Biomechanical studies often employ optical motion capture systems for the determination of the position of an object in a room-based coordinate system. This is not ideal for many types of study in locomotion since only a few strides may be collected per `trial', and outdoor experiments are difficult with some systems. Here, we report and evaluate a novel approach that enables the user to determine linear displacements of a proprietary orientation sensor during cyclical movement. This makes experiments outside the constraints of the laboratory possible, for example to measure mechanical energy fluctuations of the centre of mass during over-ground locomotion. Commercial orientation sensors based on inertial sensing are small and lightweight and provide a theoretical framework for determining position from acceleration. In practice,the integration process is difficult to implement because of integration errors, integration constants and the necessity to determine the orientation of the measured accelerations. Here, by working within the constraints of cyclical movements, we report and evaluate a method for determining orientation and relative position using a modified version of a commercial inertial orientation sensor that combines accelerometers, gyroscopes and magnetometers, thus giving a full set of movement parameters (displacement,velocity and acceleration in three dimensions). The 35 g sensor was attached over the spine of a horse exercising on a treadmill. During canter locomotion(9.0 m s-1), the amplitudes of trunk movement in the x(craniocaudal), y (mediolateral) and z (dorsoventral)directions were 99.6, 57.9 and 140.2 mm, respectively. Comparing sensor displacement values with optical motion capture values for individual strides,the sensor had a median error (25th, 75th percentile) in the x, y and z directions of 0.1 (–9.7, +10.8), –3.8(–15.5, +13.7) and –0.1 (–6.3, +7.1) mm, respectively. High-pass filtering of the displacement data effectively separated non-cyclical from cyclical components of the movement and reduced the interquartile ranges of the errors considerably to (–3.6, 6.2),(–4.0, 3.8) and (–4.5, 5.1) for x, y and z displacement, respectively, during canter locomotion. This corresponds to (–3.2, 5.5)%, (–6.7, 6.3)% and (–3.3, 3.7)%of the range of motion.

Measurement of peak vertical ground reaction force (GRFz) from multiple limbs simultaneously during highspeed, over-ground locomotion would enhance our understanding of the locomotor mechanics of cursorial animals. Here, we evaluate the accuracy of predicting peak GRFz from duty factor (the proportion of the stride for which the limb is in contact with the ground). Footmounted uniaxial accelerometers, combined with UHF FM telemetry, are shown to be practical and accurate for the field measurement of stride timing variables, including duty factor. Direct comparison with the force plate produces a mean error of 2.3·ms and 3.5·ms for the timing of foot on and foot off, respectively, across all gaits. Predictions of peak GRFz from duty factor show mean errors (with positive values indicating an overestimate) of 0.8±0.04·N·kg -1 (13%; N=42; mean ± S.E.M.) at walk, -0.3±0.06·N·kg -1 (3%; N=75) at trot, -2.3±0.27·N·kg -1 (16%; N=18) for the non-lead limb at canter and +2.1±0.7·N·kg -1 (19%; N=9) for the lead limb at canter. The substantial over-and underestimate seen at canter, in the lead and non-lead limbs, respectively, is attributed to the different functions performed by the two limbs in the asymmetrical gaits. The difference in load experienced by the lead and non-lead limbs decreased with increasing speed.

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SUMMARY Stride duration, stance duration and protraction duration are key variables when describing the gaits of terrestrial animals. Together, they determine the duty factor (the fraction of the stride for which the limb maintains contact with the ground surface), from which the peak vertical force can be estimated. When an animal changes speed, these variables change at different proportions. Limited measurements of these variables and predictions of peak limb force have been undertaken for large mammals performing high-speed over-ground exercise. This study set out to make such measurements, employing a previously validated system consisting of limb-mounted accelerometers and a Global Positioning System data logger. Measurements were made on nine elite Thoroughbred racehorses during gallop locomotion over a range of speeds from 9 to 17 m s-1. No statistically significant differences were seen in any variables between the lead and non-lead limbs for either the fore or hind pairs of limbs. Mean stance durations of 131 and 77 ms in the forelimbs and 143 and 94 ms in the hindlimbs were recorded at speeds of 9 and 17 ms-1, respectively. Equivalent values for protraction duration were 364 and 342 (fore) and 355 and 326 ms (hind). Peak limb forces (from duty factor) at 17 ms-1 were 24.7 N kg-1 body weight (range 22.6 to 26.0 N kg-1 body weight) for the forelimbs and 15.3 N kg-1 (range 13.7-16.2 N kg-1 body weight) for the hindlimbs. The duration of the aerial phase of the stride (when no limbs are in contact with the ground) was independent of speed. Overlap time (when more than one leg is on the ground) dropped with speed and approached zero at maximum speed.

SUMMARY During locomotion cyclical interchange between different forms of mechanical energy enhances economy; however, 100% efficiency cannot be achieved and ultimately some mechanical work must be performed de novo. There is a metabolic cost associated with fluctuations in mechanical energy, even in the most efficient animals. In this study we investigate the exchanges between different forms of mechanical energy involved in high-speed gallop locomotion in Thoroughbred race horses during over-ground locomotion using innovative, mobile data collection techniques. We use hoof-mounted accelerometers to capture foot contact times, a GPS data logger to monitor speed and an inertial sensor mounted over the dorsal spinous processes of the fourth to sixth thoracic vertebrae (the withers) of the horse to capture trunk movement with six degrees of freedom. Trunk movement data were used to estimate the movement of the centre of mass (CoM). Linear(craniocaudal, mediolateral and dorsoventral) and rotational (roll, pitch and heading) kinematic parameters (displacement, velocity and acceleration) were calculated for seven horses at gallop speeds ranging from 7 to 17 m s-1 during their regular training sessions. These were used to estimate external mechanical energy (potential energy and linear kinetic energy of the CoM) as well as selected components of internal energy (angular kinetic energy). Elastic energy storage in the limbs was estimated from duty factor, sine wave assumptions and published leg stiffness values. External mechanical energy changes were dominated by changes in craniocaudal velocity. Potential energy change, which was in phase with craniocaudal energy during the front limb stances, was small. Elastic energy storage in the limbs was small compared to the overall amplitude of fluctuation of external mechanical energy. Galloping at high speeds does not therefore fit classical spring mass mechanics.

Laryngoplasty should be recommended for all TB racehorses with grade III RLN to maximise return to racing at a high level. This contradicts the common approach of waiting for complete paralysis.

Summary Reasons for performing study Biological treatments for osteoarthritis (OA) are an important component of disease control. Understanding the expression of catabolic and anabolic genes during osteoarthritis progression should help to identify the major mediators of the disease. Objective To compare the cytokine and anabolic marker concentrations in synovium, synovial fluid, and cartilage between normal and osteoarthritic joints. Methods Equine carpi from horses age 2–11 years were used. Tissues were harvested at the time of surgery or euthanasia, and RNA was isolated for RT-PCR analysis. Tumor necrosis factor alpha (TNFα), interleukin-1beta (IL-1β), aggrecanase 1 (ADAMTS-4), aggrecanase 2 (ADAMTS-5), matrix metalloproteinase-13 (MMP-13), interleukin 17 (IL-17), and collagen I alpha 1(Col-1) expression was determined in synovium. TNFα, IL-1β, ADAMTS-4, ADAMTS-5, MMP-13, IL-17, collagen IIB (Col-2B), and aggrecan expression was determined in cartilage. TNFα concentration in the synovial fluid was determined by enzyme-linked immunosorbent assay (ELISA). Results Expression of TNFα, ADAMTS-5, and MMP-13 was significantly increased in synovial tissue from OA joints. Synovial membrane IL-1β abundance showed only moderate elevations in OA, without reaching significant levels. Cytokine expression was increased in OA cartilage samples, particularly for TNFα (p=0.0007), IL-1β (p<0.0001), ADAMTS-4 (p=0.0011), and MMP-13 (p<0.0001). Collagen type I expression was significantly increased in synovial tissues from OA groups. Collagen type II message was diminished in mild and moderate stages of OA, but rebounded to significant elevations in severely degenerate joints. Conversely, aggrecan levels significantly declined in all OA cartilage groups (p<0.001). Synovial fluid TNFα peptide concentration was significantly increased in severe OA cases (p=0.021). Conclusion TNFα was significantly increased in all degrees of equine OA, and was abundantly expressed in synovial membrane and cartilage. Similarly, IL-1β was overexpressed in OA cartilage, but not to a significant extent in synovium. ADAMTS-4 was more abundant in OA cartilage while ADAMTS-5 predominated in OA synovium. IL-17 expression was not observed in osteoarthritic equine synovium nor cartilage. Potential relevance Control of TNFα should be considered further as a target in the treatment of OA. ADAMTS-4 may be the primary aggrecanase causing cartilage breakdown in OA.