1,851 research outputs found

    Does Dietary-Induced Obesity in Old Age Impair the Contractile Performance of Isolated Mouse Soleus, Extensor Digitorum Longus and Diaphragm Skeletal Muscles?

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    Ageing and obesity independently have been shown to significantly impair isolated muscle contractile properties, though their synergistic effects are poorly understood. We uniquely examined the effects of 9 weeks of a high-fat diet (HFD) on isometric force, work loop power output (PO) across a range of contractile velocities, and fatigability of 79-week-old soleus, extensor digitorum longus (EDL) and diaphragm compared with age-matched lean controls. The dietary intervention resulted in a significant increase in body mass and gonadal fat pad mass compared to the control group. Despite increased muscle mass for HFD soleus and EDL, absolute isometric force, isometric stress (force/CSA), PO normalised to muscle mass and fatigability was unchanged, although absolute PO was significantly greater. Obesity did not cause an alteration in the contractile velocity that elicited maximal PO. In the obese group, normalised diaphragm PO was significantly reduced, with a tendency for reduced isometric stress and fatigability was unchanged. HFD soleus isolated from larger animals produced lower maximal PO which may relate to impaired balance in older, larger adults. The increase in absolute PO is smaller than the magnitude of weight gain, meaning in vivo locomotor function is likely to be impaired in old obese adults, with an association between greater body mass and poorer normalised power output for the soleus. An obesity-induced reduction in diaphragm contractility will likely impair in vivo respiratory function and consequently contribute further to the negative cycle of obesity

    Potassium Soil Test Correlation and Calibration for Burley Tobacco Grown on an Allegheny Loam Soil

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    Burley tobacco removes large amounts of potassium (K) from soil. A 2,600 pound/A cured leaf crop removes around 200 lbs K/A/yr, with about 110 lbs of that in the leaf and 90 lbs in the stalk. Because of such a heavy soil demand for K, growers are always concerned that application of fertilizer K be sufficient for top production. The University of Kentucky\u27s Soil Testing Laboratory (Division of Regulatory Services) provides a statewide soil testing service. The Mehlich-3 soil extractant is used by the UK lab, and soil test K values from use of this extractant (reported as lbs K/A) are categorized as follows for burley tobacco: Very High, over 450; High, 450-301; Medium, 300-201; Low, 200-91; Very Low, less than 91. The amount of potash fertilizer (K2O) recommended varies from 400 lbs/A for soil test K levels below 91 to 0 when soil test K levels are above 450

    How are coastal benthos fed?

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    Water movement can influence the distribution of benthos, in part, by increasing food delivery; however, the impact of advective transport and turbulent diffusion on organic matter flux to nearshore benthic communities is not well quantified. In this study, we measured the vertical particulate organic carbon (POC) and particulate phosphorus (PP) flux in nearshore Lake Michigan using two naturally occurring daughter/parent radionuclide pairs (234Th/238U and 90Y/90Sr) and compared these fluxes to coincident benthic chamber estimates of respiration and total phosphorus efflux by quagga mussels on the lakebed. We found that advective onshore transport and vertical convective mixing increased POC and PP flux to the nearshore benthos by a factor of ~15 and ~30 over offshore trap-derived estimates of flux. From these results, we hypothesize that high benthos population densities are related to an edge effect created when the dominant mechanism of particle delivery transitions from gravitational settling to convection

    The Effect of Increasing Age on the Concentric and Eccentric Contractile Properties of Isolated Mouse Soleus and Extensor Digitorum Longus Muscles

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    There is currently a limited amount of literature investigating the age-related changes in eccentric muscle function in vitro. The present study uniquely uses the work loop technique, to better replicate in vivo muscle function, in the assessment of the age and muscle-specific changes in acute and sustained concentric and eccentric power and recovery. Whole soleus or EDL muscles were isolated from 10-week and 78-week old mice, and acute and sustained concentric and eccentric work loop power assessed. Despite an age-related increase in body and muscle mass, peak absolute power for both muscles was unaffected by age. Peak concentric power normalised to muscle mass declined significantly for each muscle, whilst peak normalised eccentric power declined only for soleus. Fatigue resistance and recovery for the soleus did not differ between age or contraction type. Older EDL was less resistant to concentric fatigue, but was better able to withstand sustained eccentric activity than young EDL. We have shown that age-related changes in muscle quality are more limited for eccentric function than concentric function. A greater bodily inertia is likely to further reduce in vivo locomotor performance in older animals.</p

    Comparing care at walk-in centres and at accident and emergency departments: an exploration of patient choice, preference and satisfaction

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    Objectives: To explore the impact of establishing walk-in centres alongside emergency departments on patient choice, preference and satisfaction. Methods: A controlled, mixed-method study comparing eight emergency departments with co-located walk-in centres with the same number of ‘traditional’ emergency departments. This paper focuses on the results of a cross-sectional questionnaire survey of users. Results: Survey data demonstrated that patients were frequently unable to distinguish between being treated at a walk-in centre or an A&E department, and even where this was the case, opportunities to exercise choice about their preferred care provider were often limited. Few made an active choice to attend a co-located walk-in centre. Patients attending walk-in centres were just as likely to be satisfied overall with the care they received as their counterparts who were treated in the co-located A&E facility, although a small proportion of walk-in centre users did report greater satisfaction with some specific aspects of their care and consultation. Conclusions: Whilst one of the key policy goals underpinning the co-location of walk-in centres next to an A&E department was to provide patients with more options for accessing healthcare and greater choice, leading in turn to increased satisfaction, this evaluation was able to provide little evidence to support this. The high percentage of patients expressing a preference for care in an established emergency department compared to a new walk-in centre facility raises questions for future policy development. Further consideration should therefore be given to the role that A&E focused walk-in centres play in the Department of Health’s current policy agenda, as far as patient choice is concerned

    Clinical and cost effectiveness of a multi-professional medication reviews in care homes (CAREMED)

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    Objectives With 70% of care home residents experiencing a medication error every day in the UK, better multi‐professional working between medical practitioners, pharmacists and care homes was recommended. The aim of this study was to determine the effectiveness (falls reduction) and cost‐effectiveness, of a multi‐professional medication review (MPMR) service in care homes for older people. Method A total of care homes in the East of England were cluster randomised to ‘usual care’ or two multi‐professional (General practitioner, clinical pharmacist and care homes staff) medication reviews during the 12‐month trial period. Target recruitment was 900 residents with 10% assumed loss to follow‐up. Co‐primary outcome measures were number of falls and potentially inappropriate prescribing assessed by the Screening Tool of Older Persons Prescriptions. Key findings A total of 826 care home residents were recruited with 324 lost to follow‐up for at least one primary outcome measure. The mean number of falls per resident per annum was 3.3 for intervention and 3.0 for control (P = 0.947). Each resident was found to be prescribed 0.69 (intervention) and 0.85 (control) potentially inappropriate medicines after 12 months (P = 0.046). No significant difference identified in emergency hospital admissions or deaths. Estimated unadjusted incremental mean cost per resident was £374.26 higher in the intervention group. Conclusions In line with other medication review based interventions in care homes, two MPMRs improved medication appropriateness but failed to demonstrate improvements in clinical outcomes. From a health system perspective costs where estimated to increase overall and therefore a different model of medicines management is required

    Gradients of glucose metabolism regulate morphogen signalling required for specifying tonotopic organisation in the chicken cochlea

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    In vertebrates with elongated auditory organs, mechanosensory hair cells (HCs) are organised such that complex sounds are broken down into their component frequencies along a proximal-to-distal long (tonotopic) axis. Acquisition of unique morphologies at the appropriate position along the chick cochlea, the basilar papilla, requires that nascent HCs determine their tonotopic positions during development. The complex signalling within the auditory organ between a developing HC and its local niche along the cochlea is poorly understood. Using a combination of live imaging and NAD(P)H fluorescence lifetime imaging microscopy, we reveal that there is a gradient in the cellular balance between glycolysis and the pentose phosphate pathway in developing HCs along the tonotopic axis. Perturbing this balance by inhibiting different branches of cytosolic glucose catabolism disrupts developmental morphogen signalling and abolishes the normal tonotopic gradient in HC morphology. These findings highlight a causal link between graded morphogen signalling and metabolic reprogramming in specifying the tonotopic identity of developing HCs

    Static output-feedback stabilization of discrete-time Markovian jump linear systems: a system augmentation approach

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    This paper studies the static output-feedback (SOF) stabilization problem for discrete-time Markovian jump systems from a novel perspective. The closed-loop system is represented in a system augmentation form, in which input and gain-output matrices are separated. By virtue of the system augmentation, a novel necessary and sufficient condition for the existence of desired controllers is established in terms of a set of nonlinear matrix inequalities, which possess a monotonic structure for a linearized computation, and a convergent iteration algorithm is given to solve such inequalities. In addition, a special property of the feasible solutions enables one to further improve the solvability via a simple D-K type optimization on the initial values. An extension to mode-independent SOF stabilization is provided as well. Compared with some existing approaches to SOF synthesis, the proposed one has several advantages that make it specific for Markovian jump systems. The effectiveness and merit of the theoretical results are shown through some numerical example
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