Purification of coagulation factor VIII using chromatographic methods. Direct chromatography of plasma in anion exchange resins

Coagulation factor VIII (FVIII) concentrates are used in the treatment of patients with Hemophilia A. Human FVIII was purified directly from plasma using anion exchange chromatography followed by gel filtration. Three Q-Sepharose resins were tested, resulting in 40% recovery of FVIII activity using Q-Sepharose XL resin, about 80% using Q-Sepharose Fast Flow and 70% using the Q-Sepharose Big Beads. The vitamin K-dependent coagulation factors co-eluted with FVIII from the anion exchange columns. In the second step of purification, when Sepharose 6FF was used, 70% of FVIII activity was recovered free from vitamin K-dependent factors.

Direct effect of PGF2 alpha pulses on PRL pulses, based on inhibition of PRL or PGF2 alpha secretion in heifers

The relationships between PRL and PGF(2 alpha) and their effect on luteolysis were studied. Heifers were treated with a dopamine-receptor agonist (bromocriptine; Bc) and a Cox-1 and -2 inhibitor (flunixin meglumine [FM]) to inhibit PRL and PGF(2 alpha), respectively. The Bc was given (Hour 0) when ongoing luteolysis was indicated by a 12.5% reduction in CL area (cm(2)) from the area on Day 14 postovulation, and FM was given at Hours 0, 4, and 8. Blood samples were collected every 8-h beginning on Day 14 until Hour 48 and hourly for Hours 0 to 12. Three groups of heifers in ongoing luteolysis were used: control (n = 7), Bc (n = 7), and FM (n = 4). Treatment with Bc decreased (P < 0.003) the PRL concentrations averaged over Hours 1 to 12. During the greatest decrease in PRL (Hours 2-6), LH concentrations were increased. Progesterone concentrations averaged over hours were greater (P < 0.05) in the Bc group than in the controls. In the FM group, no PGFM pulses were detected, and PRL concentrations were reduced. Concentrations of PGFM were not reduced in the Bc group, despite the reduction in PRL. Results supported the hypothesis that a decrease (12.5%) in CL area (cm(2)) is more efficient in targeting ongoing luteolysis (63%) than using any day from Days 14 to >= 19 (efficiency/day, 10-24%). The hypothesis that PRL has a role in luteolysis was supported but was confounded by the known positive effect of LH on progesterone. The hypothesis was supported that the synchrony of PGFM and PRL pulses represents a positive effect of PGF(2 alpha), on PRL, rather than an effect of PRL on PGF(2 alpha). (C) 2012 Elsevier Inc. All rights reserved.

An optimization study of PtSn/C catalysts applied to direct ethanol fuel cell: Effect of the preparation method on the electrocatalytic activity of the catalysts

The aim of this work was to perform a systematic study of the parameters that can influence the composition, morphology, and catalytic activity of PtSn/C nanoparticles and compare two different methods of nanocatalyst preparation, namely microwave-assisted heating (MW) and thermal decomposition of polymeric precursors (DPP). An investigation of the effects of the reducing and stabilizing agents on the catalytic activity and morphology of Pt75Sn25/C catalysts prepared by microwave-assisted heating was undertaken for optimization purposes. The effect of short-chain alcohols such as ethanol, ethylene glycol, and propylene glycol as reducing agents was evaluated, and the use of sodium acetate and citric acid as stabilizing agents for the MW procedure was examined. Catalysts obtained from propylene glycol displayed higher catalytic activity compared with catalysts prepared in ethylene glycol. Introduction of sodium acetate enhanced the catalytic activity, but this beneficial effect was observed until a critical acetate concentration was reached. Optimization of the MW synthesis allowed for the preparation of highly dispersed catalysts with average sizes lying between 2.0 and 5.0 nm. Comparison of the best catalyst prepared by MW with a catalyst of similar composition prepared by the polymeric precursors method showed that the catalytic activity of the material can be improved when a proper condition for catalyst preparation is achieved. (C) 2012 Elsevier B.V. All rights reserved.

Phototransients of 2-ethylaminodiphenylborinate generated by direct photolysis and photosensitization

Ground state interactions and excited states and transients formed after photolysis and photosensitization of 2-ethylaminodiphenylborinate (2APB) were studied by various techniques. The UV spectrum shows a large absorption band at 235 nm (epsilon = 14,500 M-1 cm(-1)) with a shoulder at 260 nm. The fluorescence spectra show increasing emission intensity with maximum at 300 nm, which shifts to the red up to 10(-3) M concentrations. At higher concentrations, the emission intensity decreases, probably due to the formation of aggregates. UV excitation in deareated solutions shows the formation of two transients at 300 and 360 nm. The latter has a lifetime of 5.7 mu s in ethanol and is totally quenched in the presence of oxygen and assigned to the triplet state of 2APB. The 300 nm peak is not affected by oxygen, has a lifetime in the order of milliseconds, and corresponds to a boron-centered radical species originated from the singlet state. A boron radical can also be obtained by electron transfer from triplet Safranine to the borinate (k(q) = 9.7 x 10(7) M-1 s(-1)) forming the semioxidized form of the dye. EPR experiments using DMPO show that dye-sensitized and direct UV-photolysis of 2ABP renders initially arylboron-centered radicals. (C) 2012 Elsevier B.V. All rights reserved.

A direct D-bar reconstruction algorithm for recovering a complex conductivity in 2D

A direct reconstruction algorithm for complex conductivities in W-2,W-infinity(Omega), where Omega is a bounded, simply connected Lipschitz domain in R-2, is presented. The framework is based on the uniqueness proof by Francini (2000 Inverse Problems 6 107-19), but equations relating the Dirichlet-to-Neumann to the scattering transform and the exponentially growing solutions are not present in that work, and are derived here. The algorithm constitutes the first D-bar method for the reconstruction of conductivities and permittivities in two dimensions. Reconstructions of numerically simulated chest phantoms with discontinuities at the organ boundaries are included.

Investigation of a Pt3Sn/C Electro-Catalyst in a Direct Ethanol Fuel Cell Operating at Low Temperatures for Portable Applications

A 20% Pt3Sn/C catalyst was prepared by reduction with formic acid and used in a direct ethanol fuel cell at low temperatures. The electro-catalytic activity of this bimetallic catalyst was compared to that of a commercial 20% Pt/C catalyst. The PtSn catalyst showed better results in the investigated temperature range (30 degrees-70 degrees C). Generally, Sn promotes ethanol oxidation by adsorption of OH species at considerably lower potentials compared to Pt, allowing the occurrence of a bifunctional mechanism. The bimetallic catalyst was physico-chemically characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses. The presence of SnO2 in the bulk and surface of the catalyst was observed. It appears that SnO2 can enhance the ethanol electro-oxidation activity at low potentials due to the supply of oxygen-containing species for the oxidative removal of CO and CH3CO species adsorbed on adjacent Pt active sites.

Direct assembly of a metallodendrimer encompassing seven triruthenium clusters units

A general strategy for the assembly of dendrimeric metallo-cluster species based on tritopic trinuclear ruthenium acetate complexes is demonstrated. First, a central core consisting of a [Ru3O(CH3COO)(6)(TPEB)(3)]PF6 complex (G0), where TPEB is the tripodal 1,3,5-tri-4-pyridyl-1,2-ethenylbenzene ligand, was synthesized and then reacted with the end-capping complex [Ru3O(CH3COO)(6)(py)(2)(MeOH)]PF6, thus composing the first generation shell of a dendrimer encompassing twenty-one ruthenium ions (G1). The core and dendrimeric complexes were characterized by elemental analysis, UV-Vis, H-1 NMR, ESI-MS spectrometry and Differential pulse voltammetry. All results were consistent with the structure of that multinuclear cationic dendrimeric species. The isotopologic profile of daughter fragments and the strength of the metal-ligand bonds were carefully investigated providing the fragmentation pathway for the metallo-dendrimer upon ESI-MS dissociation conditions. (C) 2012 Elsevier B.V. All rights reserved.

Direct Access to Oxidation-Resistant Nickel Catalysts through an Organometallic Precursor

The synthesis of nickel catalysts for industrial applications is relatively simple; however, nickel oxidation is usually difficult to avoid, which makes it challenging to optimize catalytic activities, metal loadings, and high-temperature activation steps. A robust, oxidation-resistant and very active nickel catalyst was prepared by controlled decomposition of the organometallic precursor [bis(1,5-cyclooctadiene)nickel(0)], Ni(COD)(2), over silica-coated magnetite (Fe3O4@SiO2). The sample is mostly Ni(0), and surface oxidized species formed after exposure to air are easily reduced in situ during hydrogenation of cyclohexene under mild conditions recovering the initial activity. This unique behavior may benefit several other reactions that are likely to proceed via Ni heterogeneous catalysis.

PtSnIr/C Anode Electrocatalysts: Promoting Effect in Direct Ethanol Fuel Cells

This study investigates the promoting effect of PtSnIr/C (1:1:1) electrocatalyst anode, prepared by polymeric precursor method, on the ethanol oxidation reaction in a direct ethanol fuel cell (DEFC). All of the materials used were 20% metal m/m on carbon. X-ray photoelectron spectroscopy (XPS) analysis showed the presence of Pt, PtOH2, PtO2, SnO2 and IrO2 at the electrocatalyst surface, indicating a possible decorated particle structure. X-ray diffractometry (XRD) analysis indicated metallic Pt and Ir as well as the formation of an alloy with Sn. Using the PtSnIr/C electrocatalyst prepared here with two times lower loading of Pt than PtSn/C E-tek electrocatalyst, it was possible to obtain the same maximum power density found for the commercial material. The main reaction product was acetic acid probably due to the presence of oxides, in this point the bifunctional mechanism is predominant, but an electronic effect should not be discarded.

Mathematical modeling and analysis of the particle interactions in the direct filtration using the colloidal theory

This work used the colloidal theory to describe forces and energy interactions of colloidal complexes in the water and those formed during filtration run in direct filtration. Many interactions of particle energy profiles between colloidal surfaces for three geometries are presented here in: spherical, plate and cylindrical; and four surface interactions arrangements: two cylinders, two spheres, two plates and a sphere and a plate. Two different situations were analyzed, before and after electrostatic destabilization by action of the alum sulfate as coagulant in water studies samples prepared with kaolin. In the case were used mathematical modeling by extended DLVO theory (from the names: Derjarguin-Landau-Verwey-Overbeek) or XDLVO, which include traditional approach of the electric double layer (EDL), surfaces attraction forces or London-van der Waals (LvdW), esteric forces and hydrophobic forces, additionally considering another forces in colloidal system, like molecular repulsion or Born Repulsion and Acid-Base (AB) chemical function forces from Lewis.

Metabolic oligosaccharide engineering of Plasmodium falciparum intraerythrocytic stages allows direct glycolipid analysis by mass spectrometry

A recent addition to the arsenal of tools for glycome analysis is the use of metabolic labels that allow covalent tagging of glycans with imaging probes. In this work we show that N-azidoglucosamine was successfully incorporated into glycolipidic structures of Plasmodium falciparum intraerythrocytic stages. The ability to tag glycoconjugates selectively with a fluorescent reporter group permits TLC detection of the glycolipids providing a new method to quantify dynamic changes in the glycosylation pattern and facilitating direct mass spectrometry analyses. Presence of glycosylphosphatidylinositol and glycosphingolipid structures was determined in the different extracts. Furthermore, the fluorescent tag was used as internal matrix for the MALDI experiment making even easier the analysis. (C) 2012 Elsevier B.V. All rights reserved.

Direct ethanol fuel cell: Electrochemical performance at 90 degrees C on Pt and PtSn/C electrocatalysts

Carbon-supported Pt-based electrocatalysts were synthesized by Pechini method for the ethanol oxidation (EOR). Physicochemical characterizations were helpful to estimate the diameters of the obtained materials ranging from 2 nm to 5 nm. Main electrochemical experiments were carried out at 90 degrees C i.e. under the working conditions of performing the single 5 cm(2) direct ethanol fuel cell (DEFC). Pt(80)Sn(20)/C was the anode catalyst which has given the highest power density of 37 mW cm(-2). Importantly, the IR spectroscopy measurements associated with the qualitative analysis done at the output of the anodic compartment of the fuel cell have shown that ethanol oxidation on Pt(80)Sn(20)/C was mainly a two-electron sustainable process. (C) 2011 Elsevier B.V. All rights reserved.

Within-plant isoprene oxidation confirmed by direct emissions of oxidation products methyl vinyl ketone and methacrolein

Isoprene is emitted from many terrestrial plants at high rates, accounting for an estimated 1/3 of annual global volatile organic compound emissions from all anthropogenic and biogenic sources combined. Through rapid photooxidation reactions in the atmosphere, isoprene is converted to a variety of oxidized hydrocarbons, providing higher order reactants for the production of organic nitrates and tropospheric ozone, reducing the availability of oxidants for the breakdown of radiatively active trace gases such as methane, and potentially producing hygroscopic particles that act as effective cloud condensation nuclei. However, the functional basis for plant production of isoprene remains elusive. It has been hypothesized that in the cell isoprene mitigates oxidative damage during the stress-induced accumulation of reactive oxygen species (ROS), but the products of isoprene-ROS reactions in plants have not been detected. Using pyruvate-2-13C leaf and branch feeding and individual branch and whole mesocosm flux studies, we present evidence that isoprene (i) is oxidized to methyl vinyl ketone and methacrolein (iox) in leaves and that iox/i emission ratios increase with temperature, possibly due to an increase in ROS production under high temperature and light stress. In a primary rainforest in Amazonia, we inferred significant in plant isoprene oxidation (despite the strong masking effect of simultaneous atmospheric oxidation), from its influence on the vertical distribution of iox uptake fluxes, which were shifted to low isoprene emitting regions of the canopy. These observations suggest that carbon investment in isoprene production is larger than that inferred from emissions alone and that models of tropospheric chemistry and biotachemistryclimate interactions should incorporate isoprene oxidation within both the biosphere and the atmosphere with potential implications for better understanding both the oxidizing power of the troposphere and forest response to climate change.

Mouse Housing System Using Pressurized Cages Intraventilated by Direct-Current Microfans

We performed the initial assessment of an alternative pressurized intraventilated (PIV) caging system for laboratory mice that uses direct-current microfans to achieve cage pressurization and ventilation. Twenty-nine pairs of female SPF BALB/c mice were used, with 19 experimental pairs kept in Ply cages and 10 control pairs kept in regular filter-top (FT) cages. Both groups were housed in a standard housing room with a conventional atmospheric control system. For both systems, intracage temperatures were in equilibrium with ambient room temperature. PIV cages showed a significant difference in pressure between days 1 and 8. Air speed (and consequently airflow rate) and the number of air changes hourly in the PIV cages showed decreasing trends. In both systems, ammonia concentrations increased with time, with significant differences between groups starting on day 1. Overall, the data revealed that intracage pressurization and ventilation by using microfans is a simple, reliable system, with low cost, maintenance requirements, and incidence of failures. Further experiments are needed to determine the potential influence of this system on the reproductive performance and pulmonary integrity in mice.

Measurement of Direct Photons in Au plus Au Collisions at root s(NN)=200 GeV

We report the measurement of direct photons at midrapidity in Au + Au collisions at root s(NN) = 200 GeV. The direct photon signal was extracted for the transverse momentum range of 4 GeV/c < pT < 22 GeV/c, using a statistical method to subtract decay photons from the inclusive photon sample. The direct photon nuclear modification factor R-AA was calculated as a function of p(T) for different Au + Au collision centralities using the measured p + p direct photon spectrum and compared to theoretical predictions. R-AA was found to be consistent with unity for all centralities over the entire measured pT range. Theoretical models that account for modifications of initial direct photon production due to modified parton distribution functions in Au and the different isospin composition of the nuclei predict a modest change of R-AA from unity. They are consistent with the data. Models with compensating effects of the quark-gluon plasma on high-energy photons, such as suppression of jet-fragmentation photons and induced-photon bremsstrahlung from partons traversing the medium, are also consistent with this measurement.