128 research outputs found

    Method Families Concept: Application to Decision-Making Methods

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    International audienceThe role of variability in Software engineering grows increasingly as it allows developing solutions that can be easily adapted to a specific context and reusing existing knowledge. In order to deal with variability in the method engineering (ME) domain, we suggest applying the notion of method families. Method components are organized as a method family, which is configured in the given situation into a method line. In this paper, we motivate the concept of method families by comparing the existing approaches of ME. We detail then the concept of method families and illustrate it with a family of decision-making (DM) methods that we call MADISE

    A perspective of solutions for membrane instabilities in olefin/paraffin separations: a review

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    Light olefins are mainly produced by naphtha steam cracking, which is among the more energy intensive processes in the petrochemical industry. To save energy, some alternatives have been proposed to partially replace or combine with cryogenic distillation the conventional technology to separate olefins and paraffins. Within this aim, facilitated transport membranes, mainly with Ag+cations as selective carriers, have received great attention owing to the high selectivity and permeance provided. However, to be used industrially, the undesirable instability associated with the Ag+ cation should be considered. Poisonous agents and polymer membrane materials are sources of Ag+ deactivation. In recent years, great achievements on the separation performance have been reported, but the current challenge is to maintain the selectivity in long-term separation processes. This work presents a critical analysis of the potential causes of Ag+ deactivation and points out some alternatives that have been proposed to overcome the hurdle. This review highlights and critically analyses some perspectives of the ongoing development and application of facilitated transport membranes.The authors thank the Brazilian Federal Agency for Support and Evaluation of Graduate Education − CAPES (PDSE Grant 88881.134232/2016-01) and the Spanish Ministry of Economy, Industry and Competitiveness (CTQ2015-66078-R and CTQ2016-75158-R projects, Spain-FEDER 2014-2020) for financial support

    Expression and Membrane Topology of Anopheles gambiae Odorant Receptors in Lepidopteran Insect Cells

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    A lepidopteran insect cell-based expression system has been employed to express three Anopheles gambiae odorant receptors (ORs), OR1 and OR2, which respond to components of human sweat, and OR7, the ortholog of Drosophila's OR83b, the heteromerization partner of all functional ORs in that system. With the aid of epitope tagging and specific antibodies, efficient expression of all ORs was demonstrated and intrinsic properties of the proteins were revealed. Moreover, analysis of the orientation of OR1 and OR2 on the cellular plasma membrane through the use of a novel ‘topology screen’ assay and FACS analysis demonstrates that, as was recently reported for the ORs in Drosophila melanogaster, mosquito ORs also have a topology different than their mammalian counterparts with their N-terminal ends located in the cytoplasm and their C-terminal ends facing outside the cell. These results set the stage for the production of mosquito ORs in quantities that should permit their detailed biochemical and structural characterization and the exploration of their functional properties

    Computational Model of the Insect Pheromone Transduction Cascade

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    A biophysical model of receptor potential generation in the male moth olfactory receptor neuron is presented. It takes into account all pre-effector processes—the translocation of pheromone molecules from air to sensillum lymph, their deactivation and interaction with the receptors, and the G-protein and effector enzyme activation—and focuses on the main post-effector processes. These processes involve the production and degradation of second messengers (IP3 and DAG), the opening and closing of a series of ionic channels (IP3-gated Ca2+ channel, DAG-gated cationic channel, Ca2+-gated Cl− channel, and Ca2+- and voltage-gated K+ channel), and Ca2+ extrusion mechanisms. The whole network is regulated by modulators (protein kinase C and Ca2+-calmodulin) that exert feedback inhibition on the effector and channels. The evolution in time of these linked chemical species and currents and the resulting membrane potentials in response to single pulse stimulation of various intensities were simulated. The unknown parameter values were fitted by comparison to the amplitude and temporal characteristics (rising and falling times) of the experimentally measured receptor potential at various pheromone doses. The model obtained captures the main features of the dose–response curves: the wide dynamic range of six decades with the same amplitudes as the experimental data, the short rising time, and the long falling time. It also reproduces the second messenger kinetics. It suggests that the two main types of depolarizing ionic channels play different roles at low and high pheromone concentrations; the DAG-gated cationic channel plays the major role for depolarization at low concentrations, and the Ca2+-gated Cl− channel plays the major role for depolarization at middle and high concentrations. Several testable predictions are proposed, and future developments are discussed

    Quantitative genetic variation in carbonic anhydrase isozymes from tissues of the pig-tailed macaque, Macaca nemestrina

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    Two isozymes of carbonic anhydrase (CA I and CA II) were quantified by a radio-immunoassay in 10 different tissues of the pig-tailed macaque. There were clearly differences in relative amounts of the two isozymes, indicating a differential regulation of these two different gene products. An inherited deficiency variant reduced red cell CA I and CA II 5000-fold and 2.7-fold, respectively. In nine other tissues, CA I was reduced from approximately twofold to 110-fold, and CA II was essentially unchanged. The CA I in deficient red cells was immunochemically and electrophoretically identical to common electrophoretic variants of CA I in the pig-tailed macaque and was enzymatically active.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44174/1/10528_2004_Article_BF00485860.pd

    DNA polymorphism in the 5′ flanking region of the human carbonic anhydrase II gene on chromosome 8

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    A restriction-fragment-length polymorphism (RFLP) is described which is associated with the human carbonic anhydrase II gene ( CA2 ) that codes for one of the three genetically distinct carbonic anhydrase isozymes, CA I, CA II, and CA III. The isolated DNA was cleaved with several restriction enzymes and subjected to Southern blot hybridization analysis using a DNA probe containing the 5′ end of the human CA II gene. A two allele RFLP which was detected with the restriction endonuclease, Taq I, is expressed phenotypically on Southern blots as either a 5.4 kilobase (kb) fragment or as 4.0 and 1.4 kb fragments. These fragments result from the presence or absence of a Taq I recognition site in the 5′ flanking region approximately 1.0kb from the initiation codon of the CA II gene. Segregation analysis showed that the alleles are inherited in a Mendelian fashion, with a frequency of 50%.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47613/1/439_2004_Article_BF00291652.pd

    Sibling recognition in thirteen-lined ground squirrels: effects of genetic relatedness, rearing association, and olfaction

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    I investigated sibling-sibling recognition in captive thirteen-lined ground squirrels ( Spermophilus tridecemlineatus ) by cross-fostering lab-born pups shortly after birth. When young reached about 45 days of age, I observed dyadic interactions in a test arena of pairs from four relatedness X rearing groups, and recorded the frequency of “exploratory” encounters between individuals. Sibs-reared together and nonsibs-reared together exhibited significantly fewer exploratory encounters than either sibs-reared apart or nonsibsreared apart. Young reared together were equally exploratory, regadless of relatedness; similarly, young reared apart, whether they were sibs or nonsibs, showed similar levels of exploration. Thus, the differential treatment of siblings in the lab appears to be based on rearing association and not genetic relatedness per se. I interpret this recognition based on association (rearing familiarity) in the context of the species' social organization and compare my results on S. tridecemlineatus with similar studies on S. beldingi, S. parryii , and S. richardsonii . I also used an olfactory impairment technique (zinc sulfate) and found that differential treatment in thirteen-lined ground squirrels was influenced by olfactory cues.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46871/1/265_2004_Article_BF00299622.pd
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