In situ and ex situ spectroscopic study of poly(3-hexylthiophene) electrochemically synthesized

In this work, poly(3-hexylthiophene) (P3HT) film was synthesized electrochemically in non-aqueous media through the oxidation of the 3-hexylthiophene monomer using a standard three-electrode cell in acetonitrile with 0.100 mol L^?1 LiClO₄. The polymeric thick film was deposited on platinum plates for best quality control of the process. Cyclic voltammetry of this material showed two bands of oxidation and two bands of reduction attributed to radical cation and dication segments in the polymer chain. These were characterized by reflectance and Raman spectra, of the reduced (chemically de-doped) and oxidized (electrochemically doped) films. The generated film was subjected to anodic potentials of 1.00 and 1.45 V and characterized by an in situ Raman technique, which indicated the stabilization of the radical cation segments. In addition Raman ex situ spectra of as-prepared film was obtained. The increase in the irradiation time of the sample was enough to alter the nature of the constituent species of the oxidized film, preferably favoring the aromatic chains, together with the dication segments. Photoluminescence spectra showed a larger contribution of dication than radical cation segments for the chemically de-doped sample and under this condition showed good stability, even with variation in laser power. SEM images of P3HT film with indication of the thickness and spherical shape of the sample studied were obtained. Aided by these data it was possible to verify the Stokes shift and ionization potential (I _p), electron affinity (E.A.) and energy gap (E _g) parameters.     

Using finite element modeling to examine the temperature distribution in quasi-constrained high-pressure torsion

Processing by quasi-constrained high-pressure torsion (HPT) is important for achieving substantial grain refinement in bulk solids, but very little information is available at present on the rise in temperature that occurs in the HPT specimens during the processing operation. This problem was addressed by using finite element modeling with an analytical component to evaluate the thermal characteristics in quasi-constrained HPT. The analysis incorporates the effects of various parameters, including the material strength, the rotation rate, the applied pressure and the volume of the anvils. The calculations show that the temperature rise varies directly with the material strength and the rotation rate, but depends only slightly on the applied pressure. Using this analysis, a normalized master curve is constructed that may be used to predict the rise in temperature during HPT processing. It is demonstrated that the predictions from this curve are in good agreement with experimental data for three different materials.     

Influence of the relative amounts of crystalline and amorphous phases on the mechanical properties of polyamide-6 nanocomposites

The relative amounts of amorphous and crystalline γ- and α-phases in polyamide-6 nanocomposites, estimated from the deconvolution of X-ray diffraction peaks using Gaussian functions, correlates with their mechanical, thermomechanical, and barrier properties. The incorporation of organoclay platelets (Cloisite 15A and 30B) induced the crystallization of the polymer in the γ form at expense of the amorphous phase, such that 1–2 wt % of Cloisite is enough to enhance the mechanical and the thermomechanical properties. However, higher nanofiller loads were necessary to achieve good barrier effects, because this property is mainly dependent on the tortuous path permeation mechanism of the gas molecules through the nanocomposite films. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Adaptation for tandem cold mill models

The ideal conditions for the operation of tandem cold mills are connected to a set of references generated by models and used by dynamic regulators. Aiming at the optimization of the friction and yield stress coefficients an adaptation algorithm is proposed in this paper. Experimental results obtained from an industrial cold rolling mill are presented.     

Dynamic simulation and experimental evaluation of EPDM synthesis with ET(IND)2ZRCL2/MAO catalyst system

A mathematical model for the homogeneous terpolymerization of ethylene–propylene–diene (EPDM) in a semibatch reactor using Et(Ind)₂ZrCl₂/MAO as a catalyst system was developed and reported herein. In this study, we developed a kinetic model in order to explain the catalyst and EPDM properties such as catalyst activity, weight‐average molecular weight, and terpolymer composition, which were experimentally and theoretically obtained. For this system, a lower E/P feed ratio leads to a lower molecular weight and a broader initial molecular weight distribution, while the increase in diene concentration leads to a decrease in the catalyst activity without broadening the MWD of the resulting polymers. The proposed model accounts for these experimental trends and for some data in the literature.     

Intersecting and trimming parametric meshes on finite element shells

We present an algorithm for intersecting finite element meshes defined on parametric surface patches. The intersection curves are modelled precisely and both meshes are adjusted to the newly formed borders, without unwanted reparametrizations. The algorithm is part of an interactive shell modelling program that has been used in the design of large offshore oil structures. To achieve good interactive response, we represent meshes with a topological data structure that stores its entities in spatial indexing trees instead of linear lists. These trees speed up the intersection computations required to determine points of the trimming curves; moreover, when combined with the topological information, they allow remeshing using only local queries. Copyright © 2000 John Wiley & Sons, Ltd.     

Proteomic Landscape of Extracellular Vesicles for Diffuse Large B-Cell Lymphoma Subtyping

The role of extracellular vesicles (EVs) proteome in diffuse large B-cell lymphoma (DLBCL) pathology, subclassification, and patient screening is unexplored. We analyzed by state-of-the-art mass spectrometry the whole cell and secreted extracellular vesicles (EVs) proteomes of different molecular subtypes of DLBCL, germinal center B cell (GCB subtype), and activated B cell (ABC subtype). After quality control assessment, we compared whole-cell and secreted EVs proteomes of the two cell-of-origin (COO) categories, GCB and ABC subtypes, resulting in 288/1115 significantly differential expressed proteins from the whole-cell proteome and 228/608 proteins from EVs (adjust p-value < 0.05/p-value < 0.05). In our preclinical model system, we demonstrated that the EV proteome and the whole-cell proteome possess the capacity to separate cell lines into ABC and GCB subtypes. KEGG functional analysis and GO enrichment analysis for cellular component, molecular function, and biological process of differential expressed proteins (DEP) between ABC and GCB EVs showed a significant enrichment of pathways involved in immune response function. Other enriched functional categories for DEPs constitute cellular signaling and intracellular trafficking such as B-cell receptor (BCR), Fc_gamma R-mediated phagocytosis, ErbB signaling, and endocytosis. Our results suggest EVs can be explored as a tool for patient diagnosis, follow-up, and disease monitoring. Finally, this study proposes novel drug targets based on highly expressed proteins, for which antitumor drugs are available suggesting potential combinatorial therapies for aggressive forms of DLBCL. Data are available via ProteomeXchange with identifier PXD028267.     

Recovery and purification of lactose from whey

One of the main problems associated with the manufacturing of cheese is the production of whey, which causes environmental pollution due to its high concentration of dissolved organic substances, mostly proteins, fat and lactose. The search for economically viable and appropriate alternative uses of whey proteins and lactose is of fundamental importance. This work investigated four integrated processes, incorporating microfiltration, ultrafiltration, ion exchange, reverse osmosis and spray-drying, for the separation and purification of lactose from whey. The recovery and the purity of the final lactose product recovered were evaluated. It was shown that the process comprising of microfiltration (nominal pore size 0.2 μm), ultrafiltration UF3 (molecular weight cut-off 5 kDa), ion exchange and reverse osmosis, a lactose purity of 99.8% (including 4.2% of galactose/glucose) and an overall lactose recovery of 74% were obtained. The lactose left over in the retentate and trapped in the membrane modules and ion exchange columns could be further recovered to improve the overall recovery.     

Bond Strength and Interfacial Ultramorphology of Current Adhesive Systems

This study evaluated the bond strength and ultramorphology of the resin-dentin interfaces produced by current dental adhesive systems. Nine dentin bonding agents were investigated. Restored teeth were vertically, serially sectioned to obtain bonded slices for interfacial TEM analysis or to produce bonded beams for the microtensile bond strength test. The one-step self-etching adhesives (Futurabond® NR and Hybrid Bond®) showed lower bond strength values than the three-step etch-&-rinse adhesive system All-Bond 3. Most bonding agents presented statistically similar mean bond strength values, which ranged from 41.3 ± 17.9 to 35.0 ± 5.3 MPa. The thickness of the hybrid layer varied according to the type of adhesive system used. While the etch and rinse adhesives with alcohol as organic solvent showed bond strength means higher than 40 MPa, the self-etching systems showed bond strength lower than 40 MPa. Resin-dentin interdifusion zone and resin tags were noted in all bonded interfaces.