21 research outputs found
Module-based multiscale simulation of angiogenesis in skeletal muscle
<p>Abstract</p> <p>Background</p> <p>Mathematical modeling of angiogenesis has been gaining momentum as a means to shed new light on the biological complexity underlying blood vessel growth. A variety of computational models have been developed, each focusing on different aspects of the angiogenesis process and occurring at different biological scales, ranging from the molecular to the tissue levels. Integration of models at different scales is a challenging and currently unsolved problem.</p> <p>Results</p> <p>We present an object-oriented module-based computational integration strategy to build a multiscale model of angiogenesis that links currently available models. As an example case, we use this approach to integrate modules representing microvascular blood flow, oxygen transport, vascular endothelial growth factor transport and endothelial cell behavior (sensing, migration and proliferation). Modeling methodologies in these modules include algebraic equations, partial differential equations and agent-based models with complex logical rules. We apply this integrated model to simulate exercise-induced angiogenesis in skeletal muscle. The simulation results compare capillary growth patterns between different exercise conditions for a single bout of exercise. Results demonstrate how the computational infrastructure can effectively integrate multiple modules by coordinating their connectivity and data exchange. Model parameterization offers simulation flexibility and a platform for performing sensitivity analysis.</p> <p>Conclusions</p> <p>This systems biology strategy can be applied to larger scale integration of computational models of angiogenesis in skeletal muscle, or other complex processes in other tissues under physiological and pathological conditions.</p
Functional outcomes in symptomatic versus asymptomatic patients undergoing incisional hernia repair: Replacing one problem with another? A prospective cohort study in 1312 patients
Background: Incisional hernias can be associated with pain or discomfort. Surgical repair especially mesh reinforcement, may likewise induce pain. The primary objective was to assess the incidence of pain after hernia repair in patients with and without pre-operative pain or discomfort. The secondary objectives were to determine the preferred mesh type, mesh location and surgical technique in minimizing postoperative pain or discomfort. Materials and methods: A registry-based prospective cohort study was performed, including patients undergoing incisional hernia repair between September 2011 and May 2019. Patients with a minimum follow-up of 3â6 months were included. The incidence of hernia related pain and discomfort was recorded perioperatively. Results: A total of 1312 patients were included. Pre-operatively, 1091 (83%) patients reported pain or discomfort. After hernia repair, 961 (73%) patients did not report pain or discomfort (mean follow-up = 11.1 months). Of the pre-operative asymptomatic patients (n = 221), 44 (20%, moderate or severe pain: n = 14, 32%) reported pain or discomfort after mean follow-up of 10.5 months. Of those patients initially reporting pain or discomfort (n = 1091), 307 (28%, moderate or severe pain: n = 80, 26%) still reported pain or discomfort after a mean follow-up of 11.3 months postoperatively. Conclusion: In symptomatic incisional hernia patients, hernia related complaints may be resolved in the majority of cases undergoing surgical repair. In asymptomatic incisional hernia patients, pain or discomfort may be induced in a considerable number of patients due to surgical repair and one should be aware if this postoperative complication
Orientation de la production communautaire de viande bovine. Facteurs ayant une incidence sur la décision des agriculteurs de produire de la viande bovine = Trend of the Community production of beef. Factors affecting the decision of farmers to produce beef. Internal information on agriculture 60, June 1970. 6667/VI/70-F
Electrokinetic leakage as a tool to probe internal fouling in MF and UF membranes
International audienceTangential electrokinetic measurements are widely used to characterize membrane fouling as the membrane zeta potential is partly governed by the presence of foulant materials on its surface. However, in the case of porous materials as micro- (MF) and ultrafiltration (UF) membranes, a part of the streaming current flows through the porosity of the membrane during measurements. This electrokinetic leakage, is directly impacted by the presence of foulant materials inside the membrane porosity. Hence, this paper investigates for the first time the possibility of using electrokinetic leakage as a probe for detecting internal fouling, taking lipid fouling as example. Firstly, a lab-scale methodology combining "upside-down" fouling experiments with electrokinetic measurements demonstrated that the intensity of the electrokinetic leakage was related to the presence of internal fouling. Secondly, the concept was applied to the pilot-scale MF and UF of an oil-in-water emulsion under various transmembrane pressures (TMP). A significant impact of the TMP on the internal fouling of a MF PES membrane was highlighted, whereas almost no impact of the TMP was noticed in the case of an UF PAN membrane. The developed methodology using the quantification of the electrokinetic leakage phenomenon allows distinguishing the contributions of internal and external (surface) fouling. These findings offer new application of tangential electrokinetic measurements to gain more insight into the characterization of membrane fouling
A legitimidade da polĂtica de segurança democrĂĄtica e a doutrina de segurança nacional na ColĂŽmbia
Evaluation of Endogenous Allergens for the Safety Evaluation of Genetically Engineered Food Crops: Review of Potential Risks, Test Methods, Examples and Relevance
The safety of food produced from genetically engineered (GE) crops is assessed for potential risks of food allergy on the basis of an international consensus guideline outlined by the Codex Alimentarius Commission (2003). The assessment focuses on evaluation of the potential allergenicity of the newly expressed protein(s) as the primary potential risk using a process that markedly limits risks to allergic consumers. However, Codex also recommended evaluating a second concern, potential increases in endogenous allergens of commonly allergenic food crops that might occur due to insertion of the gene. Unfortunately, potential risks and natural variation of endogenous allergens in non-GE varieties are not understood, and risks from increases have not been demonstrated. Because regulatory approvals in some countries are delayed due to increasing demands for measuring endogenous allergens, we present a review of the potential risks of food allergy, risk management for food allergy, and test methods that may be used in these evaluations. We also present new data from our laboratory studies on the variation of the allergenic lipid transfer protein in non-GE maize hybrids as well as data from two studies of endogenous allergen comparisons for three GE soybean lines, their nearest genetic soy lines, and other commercial lines. We conclude that scientifically based limits of acceptable variation cannot been established without an understanding of natural variation in non-GE crops. Furthermore, the risks from increased allergen expression are minimal as the risk management strategy for food allergy is for allergic individuals to avoid consuming any food containing their allergenic source, regardless of the crop variety