Microsatellite Loci in the Gypsophyte Lepidium subulatum (Brassicaceae), and Transferability to Other Lepidieae

Polymorphic microsatellite markers were developed for the Ibero-North African, strict gypsophyte Lepidium subulatum to unravel the effects of habitat fragmentation in levels of genetic diversity, genetic structure and gene flow among its populations. Using 454 pyrosequencing 12 microsatellite loci including di- and tri-nucleotide repeats were characterized in L. subulatum. They amplified a total of 80 alleles (2–12 alleles per locus) in a sample of 35 individuals of L. subulatum, showing relatively high levels of genetic diversity, H_O = 0.645, H_E = 0.627. Cross-species transferability of all 12 loci was successful for the Iberian endemics Lepidium cardamines, Lepidium stylatum, and the widespread, Lepidium graminifolium and one species each of two related genera, Cardaria draba and Coronopus didymus. These microsatellite primers will be useful to investigate genetic diversity, population structure and to address conservation genetics in species of Lepidium.     

Development of 22 Polymorphic Microsatellite Loci for the Critically Endangered Morato��s Digger Toad, Proceratophrys moratoi

The Morato’s digger toad (Proceratophrys moratoi) inhabits Brazilian moist savannas and is critically endangered due to its very limited geographic distribution, reduced number of isolated populations, and evidence of population decline and local extinctions. With the objective of providing tools for the genetic study of the species, 22 polymorphic microsatellite loci were isolated and screened using DNA extracted from samples of oral mucosa cells obtained from 113 individuals representing five remnant P. moratoi populations in the Brazilian state of São Paulo. These markers presented 2–18 alleles per locus, polymorphism information content (PIC) of 0.02–0.87, observed heterozygosity of 0.02–0.96 and expected heterozygosity of 0.02–0.87. Three of the loci deviated significantly from Hardy–Weinberg equilibrium in one of the populations, possibly due to the presence of null alleles. Significant linkage disequilibrium was also detected between three pairs of loci. The molecular markers developed in this study were able to discriminate each of the individuals sampled (identity analysis). This means that they will be extremely useful for future genetic studies applied to the conservation of P. moratoi, providing a baseline for estimating the levels of genetic diversity, pedigrees, inbreeding, and population structure, which will be essential for the development of effective genetic management programs.     

Improved Production of Cyclodextrins by Alkalophilic Bacilli Immobilized on Synthetic or Loofa Sponges

This study aimed to improve the production of β-cyclodextrin (β-CD) by microbial cells immobilized on synthetic or loofa sponges both with and without the use of alginate or chitosan. The most suitable matrix for the immobilization of Bacillus firmus strain 7B was synthetic sponge and for Bacillus sphaericus strain 41 was loofa sponge. After 330 days of storage, the β-CD production by Bacillus firmus and Bacillus sphaericus remained at around 41% and 49%, respectively, of initial levels. After 24 days of immobilization on loofa sponge, Bacillus sphaericus strain 41 achieved an improved operational stability, reaching 86.6 mM β-CD after 20 days of production, compared to only 32.8 mM of β-CD produced by free Bacillus sphaericus strain 41 cells. The expected increase in β-CD production by immobilized cells of Bacillus firmus strain 7B on synthetic sponge for 4 days was not statistically different to that for cells immobilized for 24 days. The application of this process on an industrial scale using loofa sponge, an inexpensive and renewable matrix, will allow the stable production of β-CD.     

The Impact of Halogenated Phenylalanine Derivatives on NFGAIL Amyloid Formation

The hexapeptide hIAPP_22–27 (NFGAIL) is known as a crucial amyloid core sequence of the human islet amyloid polypeptide (hIAPP) whose aggregates can be used to better understand the wild-type hIAPP′s toxicity to β-cell death. In amyloid research, the role of hydrophobic and aromatic-aromatic interactions as potential driving forces during the aggregation process is controversially discussed not only in case of NFGAIL, but also for amyloidogenic peptides in general. We have used halogenation of the aromatic residue as a strategy to modulate hydrophobic and aromatic-aromatic interactions and prepared a library of NFGAIL variants containing fluorinated and iodinated phenylalanine analogues. We used thioflavin T staining, transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) to study the impact of side-chain halogenation on NFGAIL amyloid formation kinetics. Our data revealed a synergy between aggregation behavior and hydrophobicity of the phenylalanine residue. This study introduces systematic fluorination as a toolbox to further investigate the nature of the amyloid self-assembly process.     

Intrinsic deformable joints

This paper addresses the problem of reducing the constitutive behavior of relatively complex mechanical systems to lumped deformable components that connect two nodes of a multibody system. It is common practice, both in finite element and multibody system dynamics analysis, to refer the constitutive properties of lumped components to one of the nodes they connect. It is shown that this practice, here termed “attached,” could result in either underestimating or overestimating the couplings related to the finiteness of the relative rotation between the connected nodes. This work proposes an alternative formulation, here termed “intrinsic” that allows to correlate very well the behavior of general lumped deformable components with that resulting from the nonlinear finite element analysis of three-dimensional models of the components. Numerical examples, including the analysis of components that are widely used in the mechanical and aerospace industry, show how the proposed formulation can easily and accurately account for nonlinear geometrical effects, and thus deliver compact and accurate models suitable for the analysis of the global behavior of rather complex components.     

CAD-based cost calculation of mould cavities

This article introduces a method for generating and analyzing CAD models of mould cavities to compute the tool accessibility. Using information about the surface curvature, a determination of working areas for different milling head geometries becomes possible. Relating groups of surfaces with milling heads and specific cutting data allows calculating the manufacturing time of roughing and finishing operations, including the tool change time. Determining the working areas, inaccessible for milling heads, enables to estimate the volume of material that needs to be eroded. A CAD-based application of the calculation tool `Visual Form Calculator’ (VFC), developed at IFW, is presented. Using the VFC, companies of the tool and form making industry are able to generate a virtual model of the contour element in order to analyze the accessibility of the working areas of the cavity and calculate manufacturing costs.     

High Temperature Oxidation of a Work Roll Grade High Speed Steel

High speed steels are used for the manufacture of the work rolls used in hot rolling steel mills. An understanding of the degradation phenomena of work rolls is essential, particularly in fields related to the oxidation of the surface, given the importance of the surface quality of the rolled product at the end of the process and its close relation with the changes experienced by the surface of the rolls. The high temperature oxidation behaviour of a work roll grade high speed steel was studied using gravimetric means under isothermal conditions at 550 and 615 °C in dry air and in a mixture of dry air and water vapour. At both temperatures, the mass gain of the samples exposed to the mixture of dry air and water vapour was considerably higher than that of the samples exposed to dry air. For all the experimental conditions, oxide growth was better described by the parabolic rate law. The composition of the oxide layer was influenced by the oxidant atmosphere, as the layer in the water vapour containing environment included an iron-chromium spinel (M₃O₄), magnetite and hematite, whereas the layer in the dry air condition consisted of iron?Cchromium spinel, hematite and vanadium oxide. The effect of composition of the oxidant atmosphere on the rate of oxidation of the steel and the components of the oxide scale is discussed.     

Improving Powder Injection in Plasma Spraying by Optical Diagnostics of the Plasma and Particle Characterization

Powder injection parameters such as gas flow, injection angle, and injector position strongly influence the particle beam and thus coating properties. The interaction of the injection conditions on particle properties based on DPV-2000 measurements using the single-cathode F4 torch is presented. Furthermore, the investigation of the plasma plume by emission computer tomography is described when operating the three-cathode TriplexPro? torch. By this imaging technology, the three-dimensional shape of the radiating plasma jet is reproduced based on images achieved from three CCD cameras rotating around the plume axis. It is shown how the formation of the plasma jet changes with plasma parameters and how this knowledge can be used to optimize particle injection.