Synthesis of dahllite through a cement setting reaction

Dahllite is a synthetic carbonated hydroxyapatite with a carbonate ion content similar to bone mineral. The first objective of this study was to investigate the stoichiometric conditions under which dahllite formation occurs in a powder mixture of -Ca3(PO4)2, Ca(H2PO4)2 and CaCO3. The second objective was to identify how these conditions apply to commercially available cement, Skeletal Repair System (SRSTM), and other -Ca3(PO4)2-based cements currently under investigation. The stoichiometric coefficients were found to be a function of both the percentage of carbonate ions incorporated into the hydroxyapatite structure, and the amount of CO2 released during the reaction. As a consequence, a stability field has been obtained where different initial proportions of the reactants in the powder mixture should give the same reaction product if sufficient CO2 is released into the solution. However, increasing amounts of CaCO3 in the initial mixture have been shown to affect the solution pH in such a way that only partial reaction of the reactants takes place. SRSTM and other -Ca3(PO4)2-based cements have been located inside the stability field and a comparison between their reported setting and hardening properties has been performed. © 1998 Kluwer Academic Publishers     

Distinct annexin subfamilies in plants and protists diverged prior to animal annexins and from a common ancestor

Annexin homologues in the kingdoms of Planta and Protista were characterized by molecular sequence analysis to determine their phylogenetic and structural relationship with annexins of Animalia. Sequence fragments from 19 plant annexins were identified in sequence databases and composite sequences were also assembled from expressed sequence tags for Arabidopsis thaliana. Length differences in protein aminotermini and evidence for unique exon splice sites indicated that plant annexins were distinct from those of animals. A third annexin gene of Giardia lamblia (Anx21-Gla) was identified as a distant relative to other protist annexins and to those of higher eukaryotes, thus providing a suitable outgroup for evolutionary reconstruction of the family tree. Rooted evolutionary trees portrayed protist, plant, and Dictyostelium annexins as early, monophyletic ramifications prior to the appearance of closely related animal annexin XIII. Molecular phylogenetic analyses of DNA and protein sequence alignments revealed at least seven separate plant subfamilies, represented by Anx18 (alfalfa, previously classified), Anx22 (thale cress), Anx23 (thale cress, cotton, rape and cabbage), Anx24 (bell pepper and tomato p34), Anx25 (strawberry, horseradish, pea, soybean, and castor bean), Anx26-Zma, and Anx27-Zma (maize). Other unique subfamilies may exist for rice, tomato p35, apple, and celery annexins. Consensus sequences compiled for each eukaryotic kingdom showed some breakdown of the "annexin-fold" motif in repeats 2 and 3 of protist and plant annexins and a conserved codon deletion in repeat 3 of plants. The characterization of distinct annexin genes in plants and protists reflects their comparable diversity among animal species and offers alternative models for the comparative study of structure-function relationships within this important gene family.     

Toward Diffusion Measurements of Colloidal Nanoparticles in Biological Environments by Nuclear Magnetic Resonance

Protein corona formation on the surface of nanoparticles (NPs) is observed in situ by measuring diffusion coefficients of the NPs under the presence of proteins with a ¹⁹F nuclear magnetic resonance (NMR) based methodology. Formation of a protein corona reduces the diffusion coefficient of the NPs, based on an increase in their effective hydrodynamic radii. With this methodology it is demonstrated that the apparent dissociation constant of protein–NP complexes may vary over at least nine orders of magnitude for different types of proteins, in line with the Vroman effect. Using this methodology, the interaction between one type of protein and one type of nanoparticle can be studied quantitatively. Due to the NMR‐based detection, this methodology has no interference by absorption/scattering effects, by which optical detection schemes are affected. By using the potential of the NMR chemical shift, the detection of multiple ¹⁹F signals simultaneously opens the possibility to study the diffusion of several NPs at the same time. The ¹⁹F labeling of the NPs has negligible effect on their acute toxicity and moderate effect on NPs uptake by cells.     

Industrial use of HiPIMS and the hiP‐V hiPlus technology

It has been demonstrated by several groups that HiPIMS is a state of the art tool for applying demanding coatings with superior film properties. The real industrial breakthrough for the HiPIMS‐technology, has not yet happened. On the other hand, the up till now available HiPIMS‐PS were mainly been up‐scaled “prototypes”, far away from industrial work horses. With the hiP‐V HiPIMS power system, a direct derivative of a robust power supply technology already in commercial use for public transportation systems, another milestone is set to make the HiPIMS technology go mainstream. HiPIMS is not a revolution that will make all other technologies obsolete, yet it is a very powerful complement. With a reliable, multi‐functional power supply and with a rapid arc‐handling, it could possibly be a start of a new era in thin film production. Just consider the possibility of etching and implantation to increase cleanliness and adhesion of the samples. Until now, most of the R&D work done in HiPIMS, has been dedicated to hard coatings and tool coatings. Here, HiPIMS is surely useful but not the expected technological breakthrough. For the future, the implementation of the new positive reverse pulse, the hiP‐V hiPlus HiPIMS technology, is opening a whole new field of possible applications for i.e. nonconductive substrates where no bias can be applied. Glass and plastics can be processed with remarkable results in hardness, enhanced film properties and additionally, it is achieved at lower substrate temperatures. It has been a slow start for HiPIMS, but the future looks bright.     

Application of security reference architecture to Big Data ecosystems in an industrial scenario

Big Data environments are typically very complex ecosystems; this means that implementing them is complicated. One possible technique with which to address this complexity is the use of abstraction. Reference architecture (RA) can be useful for an improved understanding of the main components of Big Data. Herein, we propose a security RA that includes the management of security concerns and provides the main elements of a Big Data ecosystem. Application of this architecture to real-world scenarios facilitates its refinement and improves its usefulness. In this article, we present a case study of a real-world Big Data ecosystem implemented in a banking environment. This ecosystem was developed by everis, an NTT company with which we collaborated for this study. To conduct this validation case study, a map was established between the elements of the Big Data ecosystem implemented and our proposal. Consequently, a series of valuable lessons that can improve both our architecture and the security of the Big Data environment were obtained. These include recommendations for a set of best practices such as the use of security patterns.     

Assessing and discovering parallelism in C$$$$ code for heterogeneous platforms

Massively parallel architectures are mainly based on a parallel heterogeneous setup. They are composed by different computing devices that speed up specific code regions, named kernels. These kernels are usually executed offline in the corresponding devices. Porting applications to a specific heterogeneous platform is a costly task in terms of time and human resources. The key points in the porting process are the manual analysis of the source code and kernel detection. Each device of these heterogeneous platforms has their own restrictions, such as the memory allocation support. Kernels must be mapped with suitable computing devices. We introduced AKI as an automatic kernel identification and annotation tool that aims to identify potential kernels on C\(++\) sequential applications. AKI identifies those kernels that can be offlined on heterogeneous computing devices. To annotate these kernels, REPARA C++ attributes have been defined. This annotation mechanism can aid future automatic source-to-source transformation tools to facilitate the work for parallel heterogeneous platforms. AKI has been evaluated over all benchmarks included in the NAS suite. The benchmark suite incorporates a big set of realistic high performance applications. The evaluation results demonstrate that AKI is a competitive solution for identifying and annotating parallel code fragments (aka kernels).     

A multi-sequences MRI deep framework study applied to glioma classfication

Multimedia Tools and Applications - Glioma is one of the most important central nervous system tumors, ranked 15th in the most common cancer for men and women. Magnetic Resonance Imaging (MRI)...     

Grafting of vinyl acetate–methyl acrylate mixture onto cellulose. Effect of inorganic salts

The effect of the addition of NaNO₃ and NaCl on the graft copolymerization of a mixture of vinyl acetate–methyl acrylate onto cellulose, using ceric ion as initiator, is examined. Several grafting parameters were measured. Presence of NaNO₃ affects the graft copolymerization by enhancing the cellulose oxidation, but it leaves almost unaffected the homopolymerization reaction. NaCl works similarly to NaNO₃. As a consequence of salt presence, ligand changes in the ceric ion complexes, as well increase in the ionic strength of the medium, are expected.     

Evaluation of the aromatic structure of coal tar pitch by solid and solution state n.m.r.

Rapid magic angle spinning has been used to obtain sideband-free high field ¹³C n.m.r. spectra of coal tar pitches in the solid state. However, the unfavourable cross-polarization and ¹H relaxation characteristics make it difficult to accurately estimate concentrations of quaternary aromatic carbon using the dipolar dephasing method. The concentrations of bridgehead aromatic carbon in the whole pitch and toluene-insoluble fraction investigated were deduced using a combination of solid and solution state n.m.r. and elemental analyses.     

Part grasping for automated disassembly

A robot grasp synthesis algorithm for automated disassembly is presented. The goal is to select grasping points in each part to be disassembled so that a previously planned disassembly sequence can be performed holding the parts firmly and avoiding collisions. The algorithm is structured in five steps in order to make it general enough to cope with different robot grippers and different geometrical data (2D or 3D). The system is learning based, and behaviour rules are automatically extracted from grasping examples given by the user, using mainly decision trees and nearest neighbour techniques. Some simulation experiments have been carried out and results with a two fingered robot gripper are presented.