191 research outputs found
Biology of Epitrix (flea beetle) and techniques for detection
Success story of the Euphresco project 'Epitrix (flea beetle) species, life cycles and detection method
Dynamic modelling and optimisation of the batch enzymatic synthesis of amoxicillin
Amoxicillin belongs to the β-lactam family of antibiotics, a class of highly consumed pharmaceutical products used for the treatment of respiratory and urinary tract infections, and is listed as a World Health Organisation (WHO) “Essential Medicine”. The demonstrated batch enzymatic synthesis of amoxicillin is composed of a desired synthesis and two undesired hydrolysis reactions of the main substrate (6-aminopenicillanic acid (6-APA)) and amoxicillin. Dynamic simulation and optimisation can be used to establish optimal control policies to attain target product specification objectives for bioprocesses. This work performed dynamic modelling, simulation and optimisation of the batch enzymatic synthesis of amoxicillin. First, kinetic parameter regression at different operating temperatures was performed, followed by Arrhenius parameter estimation to allow for non-isothermal modelling of the reaction network. Dynamic simulations were implemented to understand the behaviour of the design space, followed by the formulation and solution of a dynamic non-isothermal optimisation problem subject to various product specification constraints. Optimal reactor temperature (control) and species concentration (state) trajectories are presented for batch enzymatic amoxicillin synthesis
Invasion dynamics of Asian hornet, Vespa velutina (Hymenoptera: Vespidae) : a case study of a commune in south-west France
Asian hornet, Vespa velutina Lepeletier nests were discovered in 2007 in Andernos-les-Bains on the south-west coast of France, 3 years after the first reported sightings in France. The number of nests increased in the commune over the following 7 years, despite local authorities enacting a destruction policy. The nests existed in close proximity to one another leading to a high density of over 10 nests per square kilometre in urban areas. New information on the chosen habitat for nests is presented, and the differences between primary and secondary locations are evident, with primary nests mostly occupying buildings and man-made structures, while secondary nests were found on trees. Using Bayesian inference methods, we fit a basic model to the observational data, which allows us to estimate key demographic parameters. This model fit is highly informative for predicting V. velutina spread and colonisation of other at-risk regions, and suggests that local control has a limited impact on the spread of V. velutina once established within a region
Obesity-induced insulin resistance in human skeletal muscle is characterised by defective activation of p42/p44 MAP kinase
Insulin resistance (IR), an impaired cellular, tissue and whole body response to insulin, is a major pathophysiological defect of type 2 diabetes mellitus. Although IR is closely associated with obesity, the identity of the molecular defect(s) underlying obesity-induced IR in skeletal muscle remains controversial; reduced post-receptor signalling of the insulin receptor substrate 1 (IRS1) adaptor protein and downstream effectors such as protein kinase B (PKB) have previously been implicated. We examined expression and/or activation of a number of components of the insulin-signalling cascade in skeletal muscle of 22 healthy young men (with body mass index (BMI) range, 20–37 kg/m2). Whole body insulin sensitivity (M value) and body composition was determined by the hyperinsulinaemic (40 mU. min−1.m−2.), euglycaemic clamp and by dual energy X-ray absorptiometry (DEXA) respectively. Skeletal muscle (vastus lateralis) biopsies were taken before and after one hour of hyperinsulinaemia and the muscle insulin signalling proteins examined by western blot and immunoprecipitation assay. There was a strong inverse relationship between M-value and BMI. The most striking abnormality was significantly reduced insulin-induced activation of p42/44 MAP kinase, measured by specific assay, in the volunteers with poor insulin sensitivity. However, there was no relationship between individuals' BMI or M-value and protein expression/phosphorylation of IRS1, PKB, or p42/44 MAP kinase protein, under basal or hyperinsulinaemic conditions. In the few individuals with poor insulin sensitivity but preserved p42/44 MAP kinase activation, other signalling defects were evident. These findings implicate defective p42/44 MAP kinase signalling as a potential contributor to obesity-related IR in a non-diabetic population, although clearly multiple signalling defects underlie obesity associated IR
The entomopathogenic fungus, Metarhizium anisopliae for the European grapevine moth, Lobesia botrana Den. & Schiff. (Lepidoptera: Tortricidae) and its effect to the phytopathogenic fungus, Botrytis cinerea
The European grapevine moth, Lobesia botrana Den. & Schiff. (Lepidoptera: Tortricidae) and the gray rot fungus(Botrytis cinerea) are two important factors that cause elevated losses of productivity in vineyards globally. TheEuropean grapevine moth is one of the most important pests in vineyards around the world, not only because ofits direct damage to crops, but also due to its association with the gray rot fungus; both organisms are highlydetrimental to the same crop. Currently, there is no effective, economic, and eco-friendly technique that can beapplied for the control of both agents. On the other hand, Metarhizium anisopliae belongs to a diverse group ofentomopathogenic fungi of asexual reproduction and global distribution. Several Metarhizium isolates have beendiscovered causing large epizootics to over 300 insects? species worldwide. In this study, a simple design wasconducted to evaluate the potential of native M. anisopliae isolates as one of biological control agents against L.botrana and as possible growth inhibitors to B. cinerea. Entomopathogenic fungal strains were isolated from aridsoils under vine (Vitis vinifera) culture. Results suggest that the three entomopathogenic strains (CEP413, CEP589,and CEP591) were highly efficient in controlling larval and pupal stages of L. botrana, with mortality rates rangingfrom 81 to 98% (within 4?6 days). Also, growth inhibition over B. cinerea strains resulted in percentages rangedfrom 47 to 64%. Finally, the compatibility of the entomopathogenic strains, with seven commercial fungicides, wasevaluated. The potential of the entomopathogenic fungal strains to act as control agents is discussed.Centro de Estudios Parasitológicos y de Vectore
Control of Bemisia tabaci by entomopathogenic fungi isolated from arid soils in Argentina
Entomopathogenic Hypocreales were isolated from arid soils in Argentina using Tenebrio molitor as bait and tested for their biological performance at 30°C and 45–65% RH. Conidial germination was tested in three vegetable oils (sunflower, olive and maize) at two concentrations (1% and 10%) to evaluate their compatibility for further liquid formulations. According to radial growth and germination results, we selected four isolates to test their pathogenicity against second instar B. tabaci nymphs with the selected oil formulations at 30°C. CEP381 and CEP401 showed the highest radial growth. Isolates CEP381, CEP401, CEP413 and CEP409 (Metarhizium spp.) had similar germination percentages as compared with water control when germinated on either sunflower, olive or maize oils at 10% v/v. The highest mortality of B. tabaci was observed for the isolates CEP381 in sunflower oil and CEP401 in olive oil. Molecular identification of isolates was performed using ITS4–5 primers. All isolates belong to the Metarhizium core group. Tested isolates could grow and infect B. tabaci nymphs at 30°C in some of the vegetable oils as carriers, providing new possibilities for integrated pest management of Bemisia tabaci.Fil: Aguilera Sammaritano, Juan Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; ArgentinaFil: Lopez Lastra, Claudia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Leclerque, Andreas. Hochschule Geisenheim University; AlemaniaFil: Vazquez, Fabio. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; ArgentinaFil: Toro, Maria Eugenia. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Biotecnología; ArgentinaFil: D´Alessandro, Celeste Paola. Universidade de Sao Paulo; BrasilFil: Cuthbertson, Andrew G.S.. Independent Science Advisor; Reino UnidoFil: Lechner, Bernardo Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; Argentin
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Family status and mutual fund performance
Using a large and long sample of US and European mutual funds, we examine the impact that membership of a fund family has on performance. We test for strategic and competitive behaviours among family funds and whether this affects performance persistence and risk-taking. While we do not find evidence of stronger performance persistence among family funds versus non-family funds, we do find some significant differences in the future performance of portfolios of family and non-family funds formed on the basis of past performance. We find strong evidence that a fund's mid-year ranking within its family and within its sector affects its risk-taking over the remainder of the year. However, most interestingly, we find evidence to suggest differences in the ways in which the US and European fund management industries operate, although future microstructure research would be required to identify the industry practices and cultures that may be the source of these differences
Redox-neutral organocatalytic Mitsunobu reactions
Nucleophilic substitution reactions of alcohols are amongst the most fundamental and strategically important transformations in organic chemistry. For over half a century these reactions have been achieved using stoichiometric, and often hazardous, reagents to activate the otherwise unreactive alcohols. Here we demonstrate that a specially designed phosphine oxide promotes nucleophilic substitution reactions of primary and secondary alcohols within a redoxneutral catalysis manifold that produces water as the sole by-product. The scope of the catalytic coupling process encompasses a range of acidic pronucleophiles that allow stereospecific construction of carbon-oxygen and carbon-nitrogen bonds
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