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The objectives for this study were to (1) describe the pathogen profile in quarters from cows with clinical mastitis and in cows with subclinical mastitis in southeastern Australia; and (2) describe antimicrobial susceptibility among isolated pathogens. As a secondary objective, we aimed to compare antimicrobial resistance prevalence in pathogens isolated from clinical and subclinical mastitis samples. A convenience sample of dairy herds (n = 65) from 4 regions in southeastern Australia (Gippsland, Northern Victoria, Tasmania, Western Victoria) were invited to submit milk samples from cows with clinical and subclinical mastitis over a 14-mo period (January 2011 to March 2012). Farmers were instructed to collect aseptic quarter milk samples from the first 10 cases of clinical mastitis for each month of the study. In addition, farmers submitted composite milk samples from cows with subclinical mastitis at 1 or 2 sampling occasions during the study period. Aerobic culture and biochemical tests were used to identify isolates. Isolates were classified as susceptible, intermediate, or resistant to a panel of antimicrobial agents based on the zone of growth inhibition around antimicrobial-impregnated disks, with antimicrobial resistance (AMR) classified as nonsusceptibility by combining intermediate and resistant groups into a single category. Generalized linear mixed models were used to compare the prevalence of AMR between clinical and subclinical mastitis isolates. For clinical mastitis samples (n = 3,044), 472 samples (15.5%) were excluded for contamination. Of the remaining samples (n = 2,572), the most common results were Streptococcus uberis (39.2%), no growth (27.5%), Staphylococcus aureus (10.6%), Escherichia coli (8.4%), and Streptococcus dysgalactiae (6.4%). For subclinical mastitis samples (n = 1,072), 425 (39.6%) were excluded due to contamination. Of the remaining samples (n = 647), the most common results were no growth (29.1%), Staph. aureus (29.1%), and Strep. uberis (21.6%). The prevalence of AMR among common isolates was low for the majority of antimicrobial agents. Exploratory analysis found that the probability of Staph. aureus demonstrating resistance to penicillin was 5.16 times higher (95% confidence interval: 1.68, 15.88) in subclinical isolates relative to clinical Staph. aureus isolates. A similar association was observed for amoxicillin with subclinical Staph. aureus isolates being 4.70 times (95% confidence interval: 1.49, 14.75) more likely to be resistant than clinical Staph. aureus isolates. We concluded that the most common bacteria causing clinical mastitis in dairy herds in Australia is likely to be Strep. uberis , whereas Staph. aureus is likely to be the most common cause of subclinical mastitis. Despite decades of antimicrobial use to control these organisms, AMR appears to be uncommon. [ABSTRACT FROM AUTHOR]

Suspended fibres significantly alter fluid rheology, as exhibited in for example solutions of DNA, RNA and synthetic biological nanofibres. It is of interest to determine how this altered rheology affects flow stability. Motivated by the fact thermal gradients may occur in biomolecular analytic devices, and recent stability results, we examine the problem of Rayleigh–Bénard convection of the transversely isotropic fluid of Ericksen. A transversely isotropic fluid treats these suspensions as a continuum with an evolving preferred direction, through a modified stress tensor incorporating four viscosity-like parameters. We consider the linear stability of a stationary, passive, transversely isotropic fluid contained between two parallel boundaries, with the lower boundary at a higher temperature than the upper. To determine the marginal stability curves the Chebyshev collocation method is applied, and we consider a range of initially uniform preferred directions, from horizontal to vertical, and three orders of magnitude in the viscosity-like anisotropic parameters. Determining the critical wave and Rayleigh numbers, we find that transversely isotropic effects delay the onset of instability; this effect is felt most strongly through the incorporation of the anisotropic shear viscosity, although the anisotropic extensional viscosity also contributes. Our analysis confirms the importance of anisotropic rheology in the setting of convection. [ABSTRACT FROM AUTHOR]

Very low Reynolds number propulsion is a topic of enduring interest due to its importance in biological systems such as sperm migration in the female reproductive tract. Motivated by the fibrous nature of cervical mucus, several recent studies have considered the effect of anisotropic rheology; these studies have generally employed the classical swimming sheet model of G. I. Taylor. The models of Cupples et al. (J. Fluid Mech. vol. 812, 2017, pp. 501-524) and Shi & Powers (Phys. Rev. Fluids vol. 2, 2017, 123102) consider related problems which in a common limit (passive, slightly anisotropic) make different predictions regarding how swimming speed depends on alignment angle. In the present paper we find that this discrepancy is due to missing terms in the analysis of Cupples et al., and that when these terms are correctly included, the models agree in their common limit. We further explore the predictions of the corrected model for both passive and active cases; it is found that for certain combinations of alignment angle and activity parameter, propulsion is halted; in other cases the small amplitude asymptotic expansion is no longer valid, motivating future numerical study. [ABSTRACT FROM AUTHOR]

Taylor’s swimming sheet is a classical model of microscale propulsion and pumping. Many biological fluids and substances are fibrous, having a preferred direction in their microstructure; for example, cervical mucus is formed of polymer molecules which create an oriented fibrous network. Moreover, suspensions of elongated motile cells produce a form of active oriented matter. To understand how these effects modify viscous propulsion, we extend Taylor’s classical model of small-amplitude zero-Reynolds-number propulsion of a ‘swimming sheet’ via the transversely isotropic fluid model of Ericksen, which is linear in strain rate and possesses a distinguished direction. The energetic costs of swimming are significantly altered by all rheological parameters and the initial fibre angle. Propulsion in a passive transversely isotropic fluid produces an enhanced mean rate of working, independent of the initial fibre orientation, with an approximately linear dependence of the energetic cost on the extensional and shear enhancements to the viscosity caused by fibres. In this regime, the mean swimming velocity is unchanged from the Newtonian case. The effect of the constant term in Ericksen’s model for the stress, which can be identified as a fibre tension or alternatively a stresslet characterising an active fluid, is also considered. This stress introduces an angular dependence and dramatically changes the streamlines and flow field; fibres aligned with the swimming direction increase the energetic demands of the sheet. The constant fibre stress may result in a reversal of the mean swimming velocity and a negative mean rate of working if it is sufficiently large relative to the other rheological parameters. [ABSTRACT FROM AUTHOR]

Background: Despite massage being widely used by athletes, little scientific evidence exists to confirm the efficacy of massage for promoting both physiological and psychological recovery after exercise and massage effects on performance.Aim: To investigate the effect of massage on perceived recovery and blood lactate removal, and also to examine massage effects on repeated boxing performance.Methods: Eight amateur boxers completed two performances on a boxing ergometer on two occasions in a counterbalanced design. Boxers initially completed performance 1, after which they received a massage or passive rest intervention. Each boxer then gave perceived recovery ratings before completing a second performance, which was a repeated simulation of the first. Heart rates and blood lactate and glucose levels were also assessed before, during, and after all performances.Results: A repeated measures analysis of variance showed no significant group differences for either performance, although a main effect was found showing a decrement in punching force from performance 1 to performance 2 (p<0.05). A Wilcoxon matched pairs test showed that the massage intervention significantly increased perceptions of recovery (p<0.01) compared with the passive rest intervention. A doubly multivariate multiple analysis of variance showed no differences in blood lactate or glucose following massage or passive rest interventions, although the blood lactate concentration after the second performance was significantly higher following massage (p<0.05).Conclusions: These findings provide some support for the psychological benefits of massage, but raise questions about the benefit of massage for physiological restoration and repeated sports performance. [ABSTRACT FROM AUTHOR]

Preterm birth is common and the associated short-term morbidity well described. The adult-onset consequences of preterm birth are less clear, but cardiovascular and metabolic health may be adversely affected. Although large animal models of preterm birth addressing important short-term issues exist, long-term studies are hampered by significant logistical constraints. Current small animal models of prematurity require terminal caesarean section of the mother; both caesarean birth and early maternal care modify offspring adult cardio-metabolic function.We describe a novel method for inducing preterm labour in guinea pigs. With support comparable to that received by moderately preterm human infants, preterm pups are viable. Growth trajectories between preterm and term-born pups differ significantly; between term equivalent age and weaning ex-preterm animals demonstrate increased weight and ponderal index.We believe this novel paradigm will significantly improve our ability to investigate the cardio-metabolic sequelae of preterm birth throughout the life course and into the second generation. [ABSTRACT FROM PUBLISHER]

Understanding the processes that underlie pollen release is a prime target for controlling fertility to enable selective breeding and the efficient production of hybrid crops. Pollen release requires anther opening, which involves changes in the biomechanical properties of the anther wall. In this research, we develop and use a mathematical model to understand how these biomechanical processes lead to anther opening., Our mathematical model describing the biomechanics of anther opening incorporates the bilayer structure of the mature anther wall, which comprises the outer epidermal cell layer, whose turgor pressure is related to its hydration, and the endothecial layer, whose walls contain helical secondary thickening, which resists stretching and bending. The model describes how epidermal dehydration, in association with the thickened endothecial layer, creates forces within the anther wall causing it to bend outwards, resulting in anther opening and pollen release., The model demonstrates that epidermal dehydration can drive anther opening, and suggests why endothecial secondary thickening is essential for this process (explaining the phenotypes presented in the myb26 and nst1nst2 mutants)., The research hypothesizes and demonstrates a biomechanical mechanism for anther opening, which appears to be conserved in many other biological situations where tissue movement occurs. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to investigate whether suspension seats (SS) fitted to rigid inflatable boats (RIB) could help maritime boarding teams maintain running performance during the high-risk posttransit phase.Background: High-speed RIB transits have been reported to cause reductions in the running performance of boarding teams posttransit.Method: In this experiment, two pairs of teams completed a 3-hr transit in either calm or rough seas (calm, 5 vs. 5; rough, 6 vs. 6) in an RIB fitted with either fixed (FS) or Suspension seats (SS). Exhaustive shuttle run distance was measured pre- and immediately posttransit. Transit heart rate and perceived exertion (RPE) were measured and deck and seat pan acceleration recorded; the latter were reported as impacts count and peak magnitude.Results: Distance run was reduced for the FS teams following both transits (calm,-250 m,-20%, p < .07; rough, -398 m, -26%, p < .05), whereas it was unchanged for the SS teams. All transit heart rates and RPE indicated light exertion levels. Seat pan impacts were similarly reduced during the calm transit (FS, -42%; SS, -30%); however, during the rough transit, the SS was more than twice as effective (FS, -32%; SS, -71%). Peak impact magnitudes were reduced by the SS (calm, -38%; rough, -57%) and amplified by the FS (calm, +3%; rough, +28%).Conclusion: Suspension seats effectively maintained posttransit running performance by reducing magnitude of the vertical shocks imposed on the passengers.Application: High-speed RIB transits followed immediately by high-intensity activity are intrinsic to contemporary maritime operations; suspension seats can maintain post-transit physical performance, thereby enhancing safety and operational effectiveness. [ABSTRACT FROM AUTHOR]

The article features Countdown MAX, a veterinary service promoting improvements in the management of risks involving mastitis and milk quality. As an extension of the Countdown Downunder programme, the national mastitis and milk quality programme of Australia, it was co-developed by the Countdown Downunder programme team and a group of veterinarians, farmers and social researchers. The risk management modules developed are to be used at the drying-off and calving periods, and during lactation.

Many growing plant cells undergo rapid axial elongation with negligible radial expansion. Growth is driven by high internal turgor pressure causing viscous stretching of the cell wall, with embedded cellulose microfibrils providing the wall with strongly anisotropic properties. We present a theoretical model of a growing cell, representing the primary cell wall as a thin axisymmetric fibre-reinforced viscous sheet supported between rigid end plates. Asymptotic reduction of the governing equations, under simple sets of assumptions about the fibre and wall properties, yields variants of the traditional Lockhart equation, which relates the axial cell growth rate to the internal pressure. The model provides insights into the geometric and biomechanical parameters underlying bulk quantities such as wall extensibility, and shows how either dynamical changes in wall material properties or passive fibre reorientation may suppress cell elongation. [ABSTRACT FROM AUTHOR]

PURPOSE: To test the hypothesis that ankles with functional instability will demonstrate slower muscular reaction times than their contralateral stable ankle (SA) and stable healthy controls to a simulated nonpathological ankle sprain mechanism. METHODS: Nineteen male volunteers with a history of unilateral ankle sprain and functional ankle instability (FAI) and 19 healthy male controls performed reaction time tests on a purpose-built platform that simulated a nonpathological combined inversion/plantarflexion ankle sprain mechanism. Participants provided informed written consent. Reaction time and muscle activity magnitude data were reported for the FAI group's unstable (UA) and stable ankles (SA) and the control group's dominant (DA) and nondominant ankles (NDA) to unilateral simulated ankle sprain (USAS). RESULTS: The reaction times of the peroneus longus (PL), peroneus brevis (PB), and tibialis anterior (TA) in the UA were significantly slower (P < 0.025) than the SA and control group's DA in the limb experiencing USAS. The reaction times of the support limb PL, TA, and extensor digitorum longus (EDL) muscles of the UA were slower than the DA (P < 0.025). The magnitude of EMG response was not different between the SA and UA (P > 0.025). CONCLUSIONS: Results demonstrate a deficit (slower reaction time) in ankles with FAI when acting in support and when exposed to a simulated sprain compared to stable healthy controls. As a result of slower reaction times, acting to support the UA may put the contralateral SA at an increased risk of ankle sprain. This suggests that rehabilitation of a lateral ankle sprain should include strengthening the evertors (peroneals and EDL) at the subtalar joint and the dorsiflexors (TA and EDL) at the talocrural joint. [ABSTRACT FROM AUTHOR]

PURPOSE:: To test the hypothesis that ankles with functional instability will demonstrate greater single-limb postural sway (PS) than their contralateral stable joint and stable healthy controls and to examine the relationship between single-limb postural sway and muscular reaction time to a simulated ankle sprain mechanism. METHODS:: Nineteen male volunteers with a history of unilateral ankle sprain and functional ankle instability (FAI) and 19 healthy male controls performed 12 single-limb PS tests, 3 on each leg with and without vision. Participants provided informed consent. Postural sway data are reported on the FAI group's unstable (UA) and stable ankles (SA), and the control group's dominant (DA) and nondominant ankles (NDA). RESULTS:: With vision, the UA and SA revealed similar postural control; however, the UA showed greater (P < 0.05) anteroposterior PS than the DA (0.46 cm) and the NDA (0.51 cm). Without vision, the UA showed greater (P < 0.05) medial (2.41 cm) and lateral (2.59 cm) PS than the SA and also showed greater (P < 0.05) medial (2.05 and 2.10 cm, respectively) and lateral (2.28 and 2.26 cm, respectively) than the DA and NDA. The relationship between PS and muscle reaction times, derived from the previous article was calculated. Significant correlations (P < 0.05) were found between the unstable ankle peroneus longus (PL) and peroneus brevis (PB) reaction time and lateral (r = 0.63 and r = 0.81, respectively), medial (r = 0.74 and r = 0.76, respectively), and anterior PS (r = 0.56 and r = 0.55, respectively; P < 0.01). CONCLUSIONS:: Results reveal postural sway deficits in ankles with FAI. They also demonstrate a significant relationship between PL and PB reaction times and postural sway in UA. Individuals who sustain an acute ankle sprain and those with FAI require rehabilitation that improves proprioception, strengthens the evertors and dorsiflexors, and restores peroneal reaction time. [ABSTRACT FROM AUTHOR]

Potential damage to natural turf by the penetrating metal spikes of the traditional golf shoe has promoted the development of golf shoes with alternative designs and inserts on the outer sole. The mechanical performance characteristics of three golf shoe outer soles were assessed on a natural grass turf surface to determine the amount of traction the designs provided. A golf shoe rig utilising a prosthetic leg and foot was built and the shoe to grass interface was exposed to increasing levels of differential linear and rotatory force to determine for each shoe the limiting level of traction preventing slip. Measurements were made by a force platform system located beneath a plate to which natural grass turf was adhered. In the golf swing movement usually the complete foot is in ground contact, though sometimes only forefoot contact occurs. The mean linear traction coefficients at the shoe sole-turf interface for the forefoot and complete foot contact were 0.97 and 1.01 for the traditional seven spike (8 mm) golf shoe. Comparable figures for the design sole with seven moulded spikes were 0.91 and 1.01 and for the flat sole golf shoe with no mouldings the equivalent figures were 0.66 and 0.88. Rotational traction was assessed for the golf swing specific movements of forefoot inward rotation, complete foot inward and complete foot outward rotation. In comparison with the alternative spike shoe design, the traditional metal spike shoe limiting torque provided significantly more forefoot linear (7%) and rotational (31%) traction (P<0.05). The traditional metal spike shoe complete foot traction provided greater inward (11%) and outward (18%) rotatory traction. [ABSTRACT FROM AUTHOR]

Presents various topics related to biomechanics. Use of digital camera for data synchronization; Speed and muscular coordination during the karate punch; Relationship between rearfoot movement and medical forces during barefoot running.

Presents the results of researches related to biomechanics. Display of greater force at the biceps femoris during turning kicks of martial arts performers; Benefit of cumulative effect participation for student dance teachers.

Six male cricket bowlers (mean ± s[sub x] : age 23.5 ± 1.3 years; height 1.83 ± 0.04 m; body weight 826 ± 20 N) performed their typical bowling action at a set of stumps positioned at standard pitch length (20.1 m). A specially designed force platform rig allowed the correct positioning of two force platforms to be achieved beneath an outdoor polyflex runway (0.017 m depth) for each player's delivery stride pattern. For the back foot, the peak vertical ground reaction force was 1.95 ± 0.08 kN (2.37 ± 0.14 BW) and the braking force was 0.77 ± 0.12 kN (0.94 ± 0.16 BW). For the front foot, the peak vertical force was 4.80 ± 0.92 kN (5.75 ± 0.98 BW) and the braking force was 2.93 ± 0.56 kN (3.54 ± 0.67 BW). The mean peak vertical loading rate for front foot contact was 205 ± 52.8 kN·s[sup -1] (249 ± 64 BW·s[sup -1]) with mean values ranging from 81 to 446 kN·s[sup -1] (98 to 540 BW·s-1). The range for back foot contact was much smaller, 25-70 kN·s[sup -1] (30-85 BW·s[sup -1]), with a mean of 41.7 ± 7.10 kN·s[sup -1] (50.6 ± 8.6 BW·s[sup -1]). Mean peak impact occurred 24 ms after touchdown for the back foot and 16 ms after touchdown for the front foot. At impact, mean peak loading rates were greater for the front foot at 246 kN·s[sup -1] (298 BW·s[sup -1]), with a range of 80-483 kN·s[sup -1] (98-534 BW·s[sup -1]), than for the back foot at 65 kN·s[sup -1] (79 BW·s[sup -1]), with a range of 40-84 kN·s[sup -1] (49-110 BW·s[sup -1]). [ABSTRACT FROM AUTHOR]