Effect of mass transfer on biodesulfurization kinetics of alkylated forms of dibenzothiophene by Pseudomonas putida CECT5279

BACKGROUND: An important problem exists for the implementation of biodesulfurization technology of fuels related to the influence of mass transfer on the overall reaction rate and process yield. Pseudomonas putida CECT5279 has been shown to be one of the most promising biocatalysts, but most kinetic studies were done at small scale and their capability for the transformation of alkyl substituted forms (Cx–DBTs) has not yet been reported. RESULTS: Conversion yields and kinetic parameters were calculated under aqueous and biphasic resting cell conditions in a 2 L stirred tank reactor. In aqueous reaction media, 100% conversion of DBT, 4MDBT and 4,6DMDBT was achieved while the conversions in the presence of an organic liquid were 38% for DBT, 19.5% for 4MDBT and 16.5% for 4,6DMDBT, showing that the process is strongly affected by mass transfer between liquids. Laboratory scale–up of P. putida CECT5279 growing step was successfully carried out using a 15 L stirred tank, on the basis of the volumetric mass transfer coefficient (k_La). CONCLUSIONS: P. putida CECT5279 is capable of removing Cx–DBT compounds successfully in aqueous resting cell conditions using stirred tank reactors, but in biphasic media, mass transfer between liquids controls the process, increasing time of reaction and lowering process yield. © 2012 Society of Chemical Industry     

Multiplexed Biosensing Diagnostic Platforms Detecting Autoantibodies to Tumor-Associated Antigens from Exosomes Released by CRC Cells and Tissue Samples Showed High Diagnostic Ability for Colorectal Cancer

Colorectal cancer (CRC) is the second leading cause of cancer-related death worldwide. The five-year survival rate of CRC patients depends on the stage at diagnosis, being higher than 80% when CRC is diagnosed in the early stages but lower than 10% when CRC is diagnosed in advanced stages. Autoantibodies against specific CRC autoantigens (tumor-associated antigens (TAAs)) in the sera of patients have been widely demonstrated to aid in early diagnosis. Thus, we herein aim to identify autoantigens target of autoantibodies specific to CRC that possess a significant ability to discriminate between CRC patients and healthy individuals by means of liquid biopsy. To that end, we examined the protein content of the exosomes released by five CRC cell lines and tissue samples from CRC patients by means of immunoprecipitation coupled with mass spectrometry analysis. A total of 103 proteins were identified as potential autoantigens specific to CRC. After bioinformatics and meta-analysis, we selected 15 proteins that are more likely to be actual CRC autoantigens in order to evaluate their role in CRC prognosis by Western blot (WB) and immunohistochemistry (IHC). We found dysregulation at the protein level for 11 of these proteins in both tissue and plasma exosome samples from patients, along with an association of nine of these proteins with CRC prognosis. After validation, all but one showed a statistically significant high diagnostic ability to distinguish CRC patients and individuals with premalignant lesions from healthy individuals, either by luminescence Halotag-based beads, or by a multiplexed biosensing platform involving the use of magnetic microcarriers as solid support modified with covalently immobilized Halotag fusion proteins constructed for CRC detection. Taken together, our results highlight the usefulness of the approach defined here to identify the TAAs specific to chronic diseases; they also demonstrate that the measurement of autoantibody levels in plasma against the TAAs identified here could be integrated into a point-of-care (POC) device for CRC detection with high diagnostic ability.     

Time dependence of linear stability parameters of a BWR

In this work we present several tools to study the time dependence of the linear stability parameters of a BWR using neutron noise analysis. Particularly, we have studied the variation in time of the fundamental frequency of a signal using the short-time Fourier transform and we have compared this method with the calculation of a time dependent Power Spectral Density (PSD) function. The temporal variation of the decay ratio is analysed using a method based on an autoregressive model to fit the different blocks of the signal. The performance of the tools presented is compared analysing analytic signals and a real signal of Forsmark 1&2 Stability Benchmark.     

High surface area Mo–V–Te–Nb–O catalysts: Preparation, characterization and catalytic behaviour in ammoxidation of propane

Mo–V–Te–Nb mixed oxides with a molar ratio of 1:0.30:0.20:0.15 were prepared by citrate and dry-up method, both associated with hydrothermal treatments in the presence of a cationic surfactant (cetyl trimethylammonium bromide, CTAB), and tested in the ammoxidation of propane. The catalysts were characterized by adsorption–desorption isotherms of nitrogen at 77 K, particle size measurements, XRD, and XPS. By using the surfactant, the surface area increased significantly, and samples with surface area between 110 and 239 m²/g were obtained. These catalysts exhibited a propane conversion near 48% with selectivity to acrylonitrile of about 32% for a space velocity 30 times higher than generally reported.     

Biological tolerance of different materials in bulk and nanoparticulate form in a rat model: sarcoma development by nanoparticles.

In order to study the pathobiological impact of the nanometre-scale of materials, we evaluated the effects of five different materials as nanoparticulate biomaterials in comparison with bulk samples in contact with living tissues. Five groups out of 10 rats were implanted bilaterally for up to 12 months with materials of the same type, namely TiO2, SiO2, Ni, Co and polyvinyl chloride (PVC), subcutaneously with bulk material on one side of the vertebral column and intramuscularly with nanoparticulate material on the contralateral side. At the end of each implantation time, the site was macroscopically examined, followed by histological processing according to standard techniques. Malignant mesenchymal tumours (pleomorphic sarcomas) were obtained in five out of six cases of implanted Co nanoparticle sites, while a preneoplastic lesion was observed in an animal implanted with Co in bulk form. In the Ni group, all animals rapidly developed visible nodules at the implanted sites between 4 and 6 months, which were diagnosed as rhabdomyosarcomas. Since the ratio of surface area to volume did not show significant differences between the Ni/Co group and the TiO2/SiO2/PVC group, we suggested that the induction of neoplasia was not mediated by physical effects, but was mediated by the well-known carcinogenic impact of Ni and Co. The data from the Co group show that the physical properties (particulate versus bulk form) could have a significant influence on the acceleration of the neoplastic process.     

High Order Finite Element Method for the Lambda modes problem on hexagonal geometry

A High Order Finite Element Method to approximate the Lambda modes problem for reactors with hexagonal geometry has been developed. This method is based on the expansion of the neutron flux in terms of the modified Dubiner’s polynomials on a triangular mesh. This mesh is fixed and the accuracy of the method is improved increasing the degree of the polynomial expansions without the necessity of remeshing. The performance of method has been tested obtaining the dominant Lambda modes of different 2D reactor benchmark problems.     

On the impact of the choice of model VOC in the evaluation of V-based catalysts for the total oxidation of dioxins: Furan vs. chlorobenzene

V-based catalysts, widely developed for the catalytic abatement of dioxins, are usually studied and optimized by investigating the oxidation of model chlorinated aromatic compounds (e.g. chlorobenzene). Even though the oxygenated function included in the central aromatic ring of the molecular structure of a dioxin could influence major aspects of the catalytic process, it has never been taken into account in the reported works. In this study, furan is chosen as a model for the central oxygenated ring of a polychlorinated dibenzo furan (PCDF) and its oxidation is compared to the case of chlorobenzene. The strategy was to check systematically if the improvements of formulations enlightened from our previous investigation on chlorobenzene also remain beneficial with furan. It turned out that the use of a sulfate containing TiO₂ as support for the active VO_x phase as well as the doping of the formulation with Mo or W oxides had very different impacts in the two cases. Some improvement strategies prove to be inefficient or deleterious in the case of furan. Competition tests further suggest that the adsorption behavior of dioxin could be better imitated by furan than by chlorobenzene. These observations highlight, in the case for which working with the target pollutant is difficult (as with dioxins), that the choice of the model molecule is critical.     

Nanometer range: A new theoretical challenge for microelectronics and optoelectronics

The equation is identified, from a couple of odd percussions, which yields the pilot wave forming the aura of a particle in the space conjugate to the four-dimensional space of direct experience. This leads to a substitute of the Copenhagen Interpretation providing the frame for demonstrating Heisenberg's uncertainty principle through a theorem of Fourier analysis. Revisiting the method of space-time domain paves the way to a new era of developments, by considering that a trapped particle located in a bounded bi-dimensional space, having less than 1 eV of kinetic energy, should have an associated wavelength representing a fraction of a wave cycle. In order to face the challenge, a new optoelectronics concept is proposed to contend with the broadening of the frequency bandwidth for a particle-wave trapped in a single-electron box: quasi-virtual electrons, trapped in nanometric single-electron thin boxes, interact by absorption-emission processes with coherent electromagnetic radiations. The migration is proposed for nanoelectronic transistor fabrication from semiconductor to semi-refractor materials.     

Influence of test protocol in determining the blood response to model polymers

A multi-parametric, multi-center evaluation of three polymers was performed measuring their response to blood contact. The purpose of this study was to pinpoint differences in tests performed for assessing basic hemocompatibility on identical materials at different centers and attempt to rationalize. Assays for platelet adhesion, activation, aggregability and activation of the coagulation system in addition to an ex vivo patency assay were performed at four centers across Europe, using protocols favored by each center for determining the blood-contacting performance of a biomaterial. Three polymers were chosen for their expected blood response spanning the range of undesirable to desirable: ethylenevinylacetate (EVA), polyvinylchloride (PVC) and PVC modified with polyethylene oxide (PEO). The assays were ranked in terms of their efficacy compared to cost and simplicity. A correlation between assays was calculated, indicating the ability of one test to correctly determine the blood response compared to another. Some assays were unable to distinguish between materials, but of the assays which could, the materials were ranked in the following order: EVA; PVC; PVC-PEO, EVA producing the most undesirable response. It is concluded that many commonly used assays for determining hemocompatibility are inappropriate, but there are simple and reliable test methods available which correlate well with the more sophisticated protocols.     

Equlibrium between Liquid Fe‐Ti‐O Slags and Metallic Iron

The compositions of Fe‐Ti‐O melts in equilibrium with molten iron have been determined by melting mixtures of TiO₂, metallic iron and various additions of either Fe₂O₃ or metallic titanium in a high‐frequency induction furnace. The furnace had a vertically segmented water‐cooled copper crucible which enabled the mixture to be melted with vigorous stirring inside a freeze‐lining of about 1 mm thickness. The slag compositions were found to form a curved line in the ternary diagram FeTiO₃ – TiO₂ – Ti₂O₃ with its highest TiO₂ content slightly higher than the pseudobrookite (M₃O₅) composition FeTi₂O₅ ‐ Ti₃O₅. The slags were examined by X‐ray diffraction and microprobe analyses. For all slags the main phase was pseudobrookite (M₃O₅) solid solution with some rutile or Magnéli phase (Ti_nO_2n‐1). The most iron‐rich and the most titanium‐rich slags contained also some FeTiO₃, respectively Ti₂O₃ phase. A melting point diagram is suggested with a eutectic groove running between the M₃O₅ phase and the TiO₂ or Magnéli phase from about 1665°C for the iron‐free to the less than 1500°C for the titanium‐free slags.