363 research outputs found

    Comparing placentas from normal and abnormal pregnancies

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    This report describes work carried out at a Mathematics-in-Medicine Study Group. It is believed that placenta shape villous network characteristics are strongly linked to the placenta’s efficiency, and hence to pregnancy outcome. We were asked to consider mathematical ways to describe the shape and other characteristics of a placenta, as well as forming mathematical models for placenta development. In this report we propose a number of possible measure of placental shape, form, and efficiency, which can be computed from images already obtained. We also consider various models for the early development of placentas and the growth of the villous tree

    Analysis of the Effect of Tilling and Crop Type on Soil Structure Using 3D Laser Profilometry

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    Background and aim: Soil structure is an important indicator of the quality of soil, but detecting the early signs of soil degradation from soil structure is difficult. Developing precise instruments able to diagnose soil structure quickly is therefore critical to improve management practices. Here, the objective is to develop an instrument analysing the roughness of surfaces resulting from the fracture of soil cores, and to test the instrument’s ability to detect changes in soil structure cause by crop type and tillage. We have designed and constructed a 3D laser profilometer suitable for analysing standard soil cores. The 3D soil profiles were first assembled into a 3D surface using image analysis before roughness indicators could be computed. The method was tested by analysing how soil surface roughness was affected by crop varieties (barley and bean) and tillage (conventional tillage and no tillage). Results showed the method is precise and could reliably detect an influence of crop type and tillage on the roughness indicator. It was also observed that tillage reduced the difference in soil structure between the different cultures. Also, the soil in which barley grew had significantly lower roughness, irrespective of the tillage method. This could indicate that the roughness indicator is affected by biopores created by the root system. In conclusion, roughness indicators obtained from the fracture of soil cores can be easily obtained by laser profilometry and could offer a reliable method for assessing the effect of crop types and soil management on soil quality.</p

    Analysis of the Effect of Tilling and Crop Type on Soil Structure Using 3D Laser Profilometry

    Get PDF
    Background and aim: Soil structure is an important indicator of the quality of soil, but detecting the early signs of soil degradation from soil structure is difficult. Developing precise instruments able to diagnose soil structure quickly is therefore critical to improve management practices. Here, the objective is to develop an instrument analysing the roughness of surfaces resulting from the fracture of soil cores, and to test the instrument’s ability to detect changes in soil structure cause by crop type and tillage. We have designed and constructed a 3D laser profilometer suitable for analysing standard soil cores. The 3D soil profiles were first assembled into a 3D surface using image analysis before roughness indicators could be computed. The method was tested by analysing how soil surface roughness was affected by crop varieties (barley and bean) and tillage (conventional tillage and no tillage). Results showed the method is precise and could reliably detect an influence of crop type and tillage on the roughness indicator. It was also observed that tillage reduced the difference in soil structure between the different cultures. Also, the soil in which barley grew had significantly lower roughness, irrespective of the tillage method. This could indicate that the roughness indicator is affected by biopores created by the root system. In conclusion, roughness indicators obtained from the fracture of soil cores can be easily obtained by laser profilometry and could offer a reliable method for assessing the effect of crop types and soil management on soil quality.</p

    New perspectives on bioactivity of olive oil: evidence from animal models, human interventions and the use of urinary proteomic biomarkers

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    Olive oil (OO) is the primary source of fat in the Mediterranean diet and has been associated with longevity and a lower incidence of chronic diseases, particularly CHD. Cardioprotective effects of OO consumption have been widely related with improved lipoprotein profile, endothelial function and inflammation, linked to health claims of oleic acid and phenolic content of OO. With CVD being a leading cause of death worldwide, a review of the potential mechanisms underpinning the impact of OO in the prevention of disease is warranted. The current body of evidence relies on mechanistic studies involving animal and cell-based models, epidemiological studies of OO intake and risk factor, small- and large-scale human interventions, and the emerging use of novel biomarker techniques associated with disease risk. Although model systems are important for mechanistic research nutrition, methodologies and experimental designs with strong translational value are still lacking. The present review critically appraises the available evidence to date, with particular focus on emerging novel biomarkers for disease risk assessment. New perspectives on OO research are outlined, especially those with scope to clarify key mechanisms by which OO consumption exerts health benefits. The use of urinary proteomic biomarkers, as highly specific disease biomarkers, is highlighted towards a higher translational approach involving OO in nutritional recommendations

    Skeletal Muscle Myofibrillar and Sarcoplasmic Protein Synthesis Rates Are Affected Differently by Altitude-Induced Hypoxia in Native Lowlanders

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    As a consequence to hypobaric hypoxic exposure skeletal muscle atrophy is often reported. The underlying mechanism has been suggested to involve a decrease in protein synthesis in order to conserve O2. With the aim to challenge this hypothesis, we applied a primed, constant infusion of 1-13C-leucine in nine healthy male subjects at sea level and subsequently at high-altitude (4559 m) after 7–9 days of acclimatization. Physical activity levels and food and energy intake were controlled prior to the two experimental conditions with the aim to standardize these confounding factors. Blood samples and expired breath samples were collected hourly during the 4 hour trial and vastus lateralis muscle biopsies obtained at 1 and 4 hours after tracer priming in the overnight fasted state. Myofibrillar protein synthesis rate was doubled; 0.041±0.018 at sea-level to 0.080±0.018%⋅hr−1 (p<0.05) when acclimatized to high altitude. The sarcoplasmic protein synthesis rate was in contrast unaffected by altitude exposure; 0.052±0.019 at sea-level to 0.059±0.010%⋅hr−1 (p>0.05). Trends to increments in whole body protein kinetics were seen: Degradation rate elevated from 2.51±0.21 at sea level to 2.73±0.13 ”mol⋅kg−1⋅min−1 (p = 0.05) at high altitude and synthesis rate similar; 2.24±0.20 at sea level and 2.43±0.13 ”mol⋅kg−1⋅min−1 (p>0.05) at altitude. We conclude that whole body amino acid flux is increased due to an elevated protein turnover rate. Resting skeletal muscle myocontractile protein synthesis rate was concomitantly elevated by high-altitude induced hypoxia, whereas the sarcoplasmic protein synthesis rate was unaffected by hypoxia. These changed responses may lead to divergent adaptation over the course of prolonged exposure

    Experimental Assessment of the Role of Acetaldehyde in Alcoholic Cardiomyopathy

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    Alcoholism is one of the major causes of non-ischemic heart damage. The myopathic state of the heart due to alcohol consumption, namely alcoholic cardiomyopathy, is manifested by cardiac hypertrophy, compromised ventricular contractility and cardiac output. Several mechanisms have been postulated for alcoholic cardiomyopathy including oxidative damage, accumulation of triglycerides, altered fatty acid extraction, decreased myofilament Ca(2+ )sensitivity, and impaired protein synthesis. Despite intensive efforts to unveil the mechanism and ultimate toxin responsible for alcohol-induced cardiac toxicity, neither has been clarified thus far. Primary candidates for the specific toxins are ethanol, its first and major metabolic product - acetaldehyde (ACA) and fatty acid ethyl esters. Evidence from our lab suggests that ACA directly impairs cardiac function and promotes lipid peroxidation resulting in oxidative damage. The ACA-induced cardiac contractile depression may be reconciled with inhibitors of Cytochrome P-450 oxidase, xanthine oxidase and lipid peroxidation Unfortunately, the common methods to investigate the toxicity of ACA have been hampered by the fact that direct intake of ACA is toxic and unsuitable for chronic study, which is unable to provide direct evidence of direct cardiac toxicity for ACA. In order to overcome this obstacle associated with the chemical properties of ACA, our laboratory has used the chronic ethanol feeding model in transgenic mice with cardiac over-expression of alcohol dehydrogenase (ADH) and an in vitro ventricular myocyte culture model. The combination of both in vivo and in vitro approaches allows us to evaluate the role of ACA in ethanol-induced cardiac toxicity and certain cellular signaling pathways leading to alcoholic cardiomyopathy
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