External mechanical work in the galloping racehorse.

Horse locomotion is remarkably economical. Here, we measure external mechanical work of the galloping horse and relate it to published measurements of metabolic cost. Seven Thoroughbred horses were galloped (ridden) over force plates, under a racing surface. Twenty-six full strides of force data were recorded and used to calculate the external mechanical work of galloping. The mean sum of decrements of mechanical energy was -876 J (±280 J) per stride and increments were 2163 J (±538 J) per stride as horses were accelerating. Combination with published values for internal work and metabolic costs for galloping yields an apparent muscular efficiency of 37-46% for galloping, which would be reduced by energy storage in leg tendons. Knowledge about external work of galloping provides further insight into the mechanics of galloping from both an evolutionary and performance standpoint.

The scaling or ontogeny of human gait kinetics and walk-run transition: The implications of work vs. peak power minimization.

A simple model is developed to find vertical force profiles and stance durations that minimize either limb mechanical work or peak power demands during bipedal locomotion. The model predicts that work minimization is achieved with a symmetrical vertical force profile, consistent with previous models and observations of adult humans, and data for 487 participants (predominantly 11-18 years old) required to walk at a range of speeds at a Science Fair. Work minimization also predicts the discrete walk-run transition, familiar for adult humans. In contrast, modeled peak limb mechanical power demands are minimized with an early skew in vertical ground reaction force that increases with speed, and stance durations that decrease steadily with speed across the work minimizing walk-run transition speed. The peak power minimization model therefore predicts a continuous walk-run gait transition that is quantitatively consistent with measurements of younger children (1.1-4.7 years) required to locomote at a range of speeds but free to select their own gaits.

Acceptability and benefit of rectal irrigation in patients with Low Anterior Resection Syndrome: a qualitative study.

AIM: Low Anterior Resection Syndrome (LARS) following rectal cancer surgery impairs the patient's quality of life (QoL). Rectal Irrigation has been demonstrated to be effective for anterior resection syndrome but many surgeons do not suggest it as a treatment. This feasibility study aimed to explore treatment acceptability and the benefit of rectal irrigation in patients who developed LARS following an anterior resection for rectal cancer. METHODS: This was a qualitative study, involving semi-structured interviews. Twenty-one patients diagnosed with LARS following anterior resection for rectal cancer in a single tertiary centre were offered rectal irrigation as a treatment option. Qualitative interviews (n=17) were conducted at baseline to explore patient reported impact of LARS on QoL, treatment acceptability and factors influencing the decision to accept/decline treatment. Follow up interviews were carried out at six months for the treatment group only (n=12), to assess its practicality and impact on QoL. RESULTS: Qualitative interview findings suggest rectal irrigation is an acceptable method of treatment for LARS. Participants who perceived their symptoms to be more severe or poorly controlled were most likely to consider rectal irrigation as a treatment option. The patients who completed treatment reported improvements in their QoL, the ability to control the time of defaecation being the key benefit CONCLUSION: Clinicians should consider offering rectal irrigation as a treatment option to patients presenting with bowel dysfunction following anterior resection as it can improve symptoms. Patients who perceive that their symptoms are severe are more likely to consider treatment. This article is protected by copyright. All rights reserved.

Hughes Abdominal Repair Trial (HART) - Abdominal wall closure techniques to reduce the incidence of incisional hernias: study protocol for a randomised controlled trial.

BACKGROUND: Incisional hernias are common complications of midline closure following abdominal surgery and cause significant morbidity, impaired quality of life and increased health care costs. The 'Hughes Repair' combines a standard mass closure with a series of horizontal and two vertical mattress sutures within a single suture. This theoretically distributes the load along the incision length as well as across it. There is evidence to suggest that this technique is as effective as mesh repair for the operative management of incisional hernias; however, no trials have compared the Hughes Repair with standard mass closure for the prevention of incisional hernia formation following a midline incision. METHODS/DESIGN: This is a 1:1 randomised controlled trial comparing two suture techniques for the closure of the midline abdominal wound following surgery for colorectal cancer. Full ethical approval has been gained (Wales REC 3, MREC 12/WA/0374). Eight hundred patients will be randomised from approximately 20 general surgical units within the United Kingdom. Patients undergoing open or laparoscopic (more than a 5-cm midline incision) surgery for colorectal cancer, elective or emergency, are eligible. Patients under the age of 18 years, those having mesh inserted or undergoing musculofascial flap closure of the perineal defect in abdominoperineal wound closure, and those unable to give informed consent will be excluded. Patients will be randomised intraoperatively to either the Hughes Repair or standard mass closure. The primary outcome measure is the incidence of incisional hernias at 1 year as assessed by standardised clinical examination. The secondary outcomes include quality of life patient-reported outcome measures, cost-utility analysis, incidence of complete abdominal wound dehiscence and C-POSSUM scores. The incidence of incisional hernia at 1 year, assessed by computerised tomography, will form a tertiary outcome. DISCUSSION: A feasibility phase has been completed. The results of the study will be used to inform current and future practice and potentially reduce the risk of incisional hernia formation following midline incisions. TRIAL REGISTRATION NUMBER: ISRCTN 25616490 . Registered on 1 January 2012.

Soil surface temperatures reveal moderation of the urban heat island effect by trees and shrubs.

Urban areas are major contributors to air pollution and climate change, causing impacts on human health that are amplified by the microclimatological effects of buildings and grey infrastructure through the urban heat island (UHI) effect. Urban greenspaces may be important in reducing surface temperature extremes, but their effects have not been investigated at a city-wide scale. Across a mid-sized UK city we buried temperature loggers at the surface of greenspace soils at 100 sites, stratified by proximity to city centre, vegetation cover and land-use. Mean daily soil surface temperature over 11 months increased by 0.6 °C over the 5 km from the city outskirts to the centre. Trees and shrubs in non-domestic greenspace reduced mean maximum daily soil surface temperatures in the summer by 5.7 °C compared to herbaceous vegetation, but tended to maintain slightly higher temperatures in winter. Trees in domestic gardens, which tend to be smaller, were less effective at reducing summer soil surface temperatures. Our findings reveal that the UHI effects soil temperatures at a city-wide scale, and that in their moderating urban soil surface temperature extremes, trees and shrubs may help to reduce the adverse impacts of urbanization on microclimate, soil processes and human health.

Long-term treatment with oral N-acetylcysteine: affects lung function but not sputum inflammation in cystic fibrosis subjects. A phase II randomized placebo-controlled trial.

PURPOSE: To evaluate the effects of oral N-acetylcysteine (NAC), which replenishes systemic glutathione, on decreasing inflammation and improving lung function in CF airways. METHODS: A multicenter, randomized, double-blind proof of concept study in which 70 CF subjects received NAC or placebo orally thrice daily for 24 weeks. ENDPOINTS: primary, change in sputum human neutrophil elastase (HNE) activity; secondary, FEV(1) and other clinical lung function measures; and safety, the safety and tolerability of NAC and the potential of NAC to promote pulmonary hypertension in subjects with CF. RESULTS: Lung function (FEV(1) and FEF(25-75%)) remained stable or increased slightly in the NAC group but decreased in the placebo group (p=0.02 and 0.02). Log(10) HNE activity remained equal between cohorts (difference 0.21, 95% CI -0.07 to 0.48, p=0.14). CONCLUSIONS: NAC recipients maintained their lung function while placebo recipients declined (24 week FEV1 treatment effect=150 mL, p<0.02). However no effect on HNE activity and other selected biomarkers of neutrophilic inflammation were detected. Further studies on mechanism and clinical outcomes are warranted.

Effects of stone chewing by outdoor sows on their teeth and stomachs.

Stone chewing is a common behaviour in outdoor sows, but its effects on their teeth and stomachs have not been investigated. Tooth wear and damage was assessed by examining the heads of 58 sows culled from outdoor units and 23 culled from indoor units. Tooth damage was found in 28 per cent of outdoor and 30 per cent of the indoor sows, and tooth wear affected 88 per cent of the outdoor and 91 per cent of the indoor sows. The outdoor sows were more prone to wear on the lower molars and premolars, a pattern of wear associated with stone chewing. The stomachs of 152 outdoor sows and 47 indoor sows were examined. Stones were found in 59 of the outdoor sows but in none of those kept indoors. There was no evidence that the presence of stones damaged the stomach, or that stone chewing affected the health of the sows. The teeth of the outdoor sows were worn, but probably not sufficiently to affect their ability to eat during their relatively short productive lives.

Ecological and evolutionary processes at expanding range margins.

Many animals are regarded as relatively sedentary and specialized in marginal parts of their geographical distributions. They are expected to be slow at colonizing new habitats. Despite this, the cool margins of many species' distributions have expanded rapidly in association with recent climate warming. We examined four insect species that have expanded their geographical ranges in Britain over the past 20 years. Here we report that two butterfly species have increased the variety of habitat types that they can colonize, and that two bush cricket species show increased fractions of longer-winged (dispersive) individuals in recently founded populations. Both ecological and evolutionary processes are probably responsible for these changes. Increased habitat breadth and dispersal tendencies have resulted in about 3- to 15-fold increases in expansion rates, allowing these insects to cross habitat disjunctions that would have represented major or complete barriers to dispersal before the expansions started. The emergence of dispersive phenotypes will increase the speed at which species invade new environments, and probably underlies the responses of many species to both past and future climate change.

Efficient improvement of silage additives by using genetic algorithms.

The enormous variety of substances which may be added to forage in order to manipulate and improve the ensilage process presents an empirical, combinatorial optimization problem of great complexity. To investigate the utility of genetic algorithms for designing effective silage additive combinations, a series of small-scale proof of principle silage experiments were performed with fresh ryegrass. Having established that significant biochemical changes occur over an ensilage period as short as 2 days, we performed a series of experiments in which we used 50 silage additive combinations (prepared by using eight bacterial and other additives, each of which was added at six different levels, including zero [i.e. , no additive]). The decrease in pH, the increase in lactate concentration, and the free amino acid concentration were measured after 2 days and used to calculate a "fitness" value that indicated the quality of the silage (compared to a control silage made without additives). This analysis also included a "cost" element to account for different total additive levels. In the initial experiment additive levels were selected randomly, but subsequently a genetic algorithm program was used to suggest new additive combinations based on the fitness values determined in the preceding experiments. The result was very efficient selection for silages in which large decreases in pH and high levels of lactate occurred along with low levels of free amino acids. During the series of five experiments, each of which comprised 50 treatments, there was a steady increase in the amount of lactate that accumulated; the best treatment combination was that used in the last experiment, which produced 4.6 times more lactate than the untreated silage. The additive combinations that were found to yield the highest fitness values in the final (fifth) experiment were assessed to determine a range of biochemical and microbiological quality parameters during full-term silage fermentation. We found that these combinations compared favorably both with uninoculated silage and with a commercial silage additive. The evolutionary computing methods described here are a convenient and efficient approach for designing silage additives.

Diagnostic and therapeutic aspects of fine-wire localization biopsy for impalpable breast cancer.

During the first 2 years (July 1989 to July 1991) of the Avon Breast Screening Service, fine-wire localization biopsy was indicated in 213 impalpable breast lesions. A total of 144 lesions were benign and 69 malignant. Only four of 213 lesions (1.9 per cent) were not excised at the first localization. Factors influencing reoperation in the 69 patients with malignant impalpable lesions were examined. There was a significant association (P < 0.001) between parenchymal disturbances on mammography and invasive carcinoma, and between non-invasive carcinoma and microcalcification (P < 0.001). In 31 patients the localization biopsy was the only surgical procedure. Thirty-eight patients required further surgery: 12 underwent further local excision and 26 mastectomy. Reoperation was more frequent in patients with calcification than in those with parenchymal disturbance (P < 0.001). The most frequent indications for mastectomy were inadequate excision of widespread comedo ductal carcinoma in situ or invasive ductal carcinoma combined with extensive ductal carcinoma in situ. Fine-wire localization biopsy was a combined therapeutic and diagnostic procedure in 31 of 69 women with impalpable screen-detected lesions. The majority of patients required further surgery because radiological abnormalities underestimated the extent of disease.

In vitro suppression of segmentation in Echinococcus multilocularis with morphological transformation of protoscoleces into monozoic adults.

When protoscoleces of Echinococcus multilocularis were cultured in vitro, under axenic conditions in either monophasic or diphasic media, segmentation was suppressed in most organisms, some 70-80% of which developed into unsegmented, monozoic forms with a complete set of sexually mature male and female genitalia. The most striking feature of monozoic worms was the large lateral swelling produced by the cirrus sac the effect being to produce organisms with an unusual asymmetric shape. Worms which did not become monozoic either (a) underwent some somatic growth, developed two sets of genitalia and became 'pseudo-segmented', i.e. with the inter-proglottid membranes absent or poorly defined, or (b) became vesicular or abnormal. The mechanisms which could be involved in the suppression of somatic growth and the induction of the monozoic condition, are examined in terms of cell lineage. The possible significance of these results in understanding the evolution of the cestodes is discussed.

Renal parenchymal radiographic measurement in infants and children.

An analysis of the urograms of 433 pairs of normal human kidneys performed on patients ranging from birth to 80 years was carried out with the object of relating the mass of the renal parenchyma to the overall size of the kidney at different ages. Statistical analysis of the results showed that there was a highly significant difference in the ratio of mass to overall size in the age periods of 0-5 and 5-10 years, with a significant difference in the third quinquenium. Adult proportions are not reached until the latter half of the second decade of life. Recognition of this aspect of the process of maturation of normal kidneys is essential if radiographic measurement is to be used as a means of estimating kidney damage in the very young.