The magnetic field effect during preparation of an interpenetrated hybrid polymeric composite

An interpenetrated structure based on poly(aspartic acid), poly(ethylene glycol), and collagen was realized to be used as matrix for future coupling of bioactive substances. The magnetic field influence on the interpenetrated network formation is investigated by dynamic rheology. The results were correlated with zeta potential, conductivity, and also optical microscopy observations. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Dihydropyrimidine dehydrogenase but not thymidylate synthase expression is associated with resistance to 5-fluorouracil in colorectal cancer

BACKGROUND/AIMS: In planning adjuvant treatment of colorectal cancer, it is of critical importance to optimize the treatment by identifying subsets of patients that will respond or not to chemotherapy. Thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) are key enzymes involved in the biochemical functions of the antimetabolite 5-fluorouracil (5-FU). In searching for the factors determining the 5-FU sensitivity of colorectal cancer, TS and DPD were analyzed in relation to the inhibitory effect of 5-FU on cell proliferation in a series of human colorectal cancer cell lines. METHODOLOGY: TS and DPD protein expressions were quantified in 5 human colorectal cancer cell lines, using TS binding assay and Western blotting, respectively. Cellular growth inhibition was assessed by MTT assay after 48 hours of continuous exposure to 5-FU or cisplatin (CDDP). RESULTS: TS protein expression was detected in all but one of the cell lines studied and varied within a 17-fold range, while DPD protein expression was detectable in only one cell line (CaR1). CaR1, which expressed the highest level of DPD and no detectable TS, showed remarkable resistance to 5-FU. The other colorectal cancer cell lines with undetectable DPD expression were sensitive to 5-FU. There was no correlation between TS expression and 5-FU sensitivity. All of the cell lines studied showed similar sensitivity to CDDP. CONCLUSIONS: These data suggest that DPD, but not TS, expression predicts 5-FU sensitivity in colorectal cancer cell lines.     

Hyperbranched polyhedral oligomeric silsesquioxane (HB‐POSS) nanomaterials for high transmission and radiation‐resistant space and solar applications

Hyperbranched polycarbosiloxanes and polysiloxanes with octafunctional polyhedral oligomeric silsesquioxane (POSS) branchpoints and curable alkoxysilane or silanol end‐groups were formulated with linear polysiloxanes to fabricate transparent and robust nanostructured POSS‐containing materials for use in a range of high performance space and solar applications. The effect of methyl vs. phenyl content, architecture and linear polysiloxane mass on transmission, thermal, physical, and proton, electron and UV radiation resistance properties was determined, and the physical properties of the nanomaterials were tailored to produce adhesives, or rigid or flexible coatings as desired. The methyl formulations showed superior electron resistance relative to a commercial space control material and to a POSS‐free HB polymer control material, even when directly exposed to radiation in coating form, whereas the phenyl formulations were shown to have inferior electron and UV resistance. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3849–3861, 2013     

Enabling High-Performance NASICON-Based Solid-State Lithium Metal Batteries Towards Practical Conditions

Solid-state lithium metal batteries (SSLMBs) are promising next-generation high-energy rechargeable batteries. However, the practical energy densities of the reported SSLMBs have been significantly overstated due to the use of thick solid-state electrolytes, thick lithium (Li) anodes, and thin cathodes. Here, a high-performance NASICON-based SSLMB using a thin (60 µm) Li_1.5Al_0.5Ge_1.5(PO₄)₃ (LAGP) electrolyte, ultrathin (36 µm) Li metal, and high-loading (8 mg cm⁻²) LiFePO₄ (LFP) cathode is reported. The thin and dense LAGP electrolyte prepared by hot-pressing exhibits a high Li ionic conductivity of 1 × 10⁻³ S cm⁻¹ at 80 °C. The assembled SSLMB can thus deliver an increased areal capacity of ≈1 mAh cm⁻² at C/5 with a high capacity retention of ≈96% after 50 cycles under 80 °C. Furthermore, it is revealed by synchrotron X-ray absorption spectroscopy and in situ high-energy X-ray diffraction that the side reactions between LAGP electrolyte and LFP cathode are significantly suppressed, while rational surface protection is required for Ni-rich layered cathodes. This study provides valuable insights and guidelines for the development of high-energy SSLMBs towards practical conditions.     

Analysis of rotating membrane emulsification performance for oil droplet production based on the Taylor vortices approach

Membrane emulsification processes generally employ a cross flow of the continuous phase in order to produce shear stress. Modification of membrane emulsification for the o/w emulsion using the rotating system has been introduced such as the use of stirred cells or a rotating tubular membrane in a stationary liquid. This paper presents an examination of membrane rotation speed on droplet characteristics. The performance of rotating membrane emulsification on o/w droplet size, the coefficient of variation, and size distribution was investigated. In addition, the operated flow regime in the rotating membrane emulsification is addressed. It has been found that overall the droplet size decreased with the increase of membrane rotation speed. The droplet size below the pore size could be produced when operating at a high rotation speed (1500?rpm). The decrease of droplet size was believed due to the action of Taylor vortices on droplet detachment. Analysis of membrane rotation speed proposed that action of Taylor vortices facilitates droplet detachment. Calculation of Taylor numbers (having a value of 0–629) confirmed that the rotating membrane emulsification produced laminar flow with vortices.     

An in vitro release study of indomethacin from nanoparticles based on methyl methacrylate/glycidyl methacrylate copolymers

Indomethacin was coupled onto some macromolecular nanostructures based on methyl methacrylate copolymers with glycidyl methacrylate and tested as a model drug. The polymeric matrices were synthesized by radical emulsion copolymerization with and without the presence of a continuous external magnetic field of 1500 Gs intensity. Mathematical analysis of the release data was performed using Higuchi, Peppas–Korsmeyer equations. NIR chemical imaging (NIR-CI) was used to provide information about the spatial distribution of the components in the studied nanostructures. This opportunity was used to visualize the spatial distribution of bioactive substances (indomethacin) into the polymeric matrix, as well as to evaluate the degree of chemical and/or physical heterogeneity of the bioactive samples. The release rate dependence on the synthesis conditions as well as on the chemical compositions of the tested polymeric systems, it was also evidenced.     

Cauliflower‐shaped ternary nanocomposites with enhanced power and energy density for supercapacitors

The present research work aimed to study the electrochemical performance of the rGO/PPY/PANI ternary nanocomposite electrodes for supercapacitor applications. The nanocomposites have been prepared by physical blending of rGO with conducting polymers PANI and PPY in five different ratios. The prepared nanocomposites were examined by XRD, IR, Raman, SEM, and XAS characterizations, and from the results, it was found that ternary nanocomposites formed in cauliflower shape, in which PPY and PANI nanoparticles are decorated on to the rGO matrix. In addition, the electrochemical performance of the prepared nanocomposites were studied using cyclic voltammetry, galvanostatic charge‐discharge, and electrochemical impedance spectroscopic studies. The highest values of capacitance, energy density, and power density values achieved were 317.5 F/g, 254 Wh/kg, and 1508.9 W/kg for nanocomposite, respectively, as expected from the synergistic properties of two types of electrode materials resulting in the nanocomposites with hybrid and improved properties. Further, the cyclic stability was also analyzed by performing 4000 long cycles, and the retained capacitance during such long cycles indicates the high potential of rGO/PPY/PANI ternary nanocomposites as electrodes for future energy requirement.     

Measurements and correlations of physico-chemical properties to composition of pseudo-binary mixtures with biodiesel

Biodiesel + diesel fuel mixtures are commonly used in the last years especially in the transport area, in order to reduce environment pollution, and the dependency on the imported fossil fuels. Some of the basic properties of these mixtures, especially density and viscosity, strongly influence spray properties, atomization and combustion processes, engine deposits formation, engine behavior in cold weather conditions, being used as input data for predictive engine combustion models. In this study pseudo-binary biodiesel + diesel fuel and biodiesel + benzene mixtures were prepared and densities, viscosities, and refractive indices of mixtures were measured at 298.15 K. The accuracy of different mixing rules and empirical equations used to estimate these properties was evaluated. The density of the studied mixtures can be predicted with a very good accuracy using Kay’s mixing rule or empirical equations obtained from regression analysis. The viscosity of biodiesel + petroleum diesel fuel can be predicted with a very good accuracy using the empirical equations. The viscosities of the two types of biodiesel mixtures are predicted with lower accuracy using Grunberg–Nissan modified equation or one equation developed for petroleum fractions. Density-refractive index and viscosity-refractive index correlations have been developed.     

DeltaE effect for polycrystalline ferromagnetic rods.

We performed experimental and computational studies of the acoustic transfer power coefficient for carbon steel cylindric bars placed in axial magnetic field. By experiment, the transmission coefficients of velocity were measured for ferromagnetic bars during the first magnetization curve below saturation. Using the magnetic and magnetostriction material measurements we obtained the profile of the magnetostriction along the distance for a ferromagnetic cylindrical rod placed in a magnetic field parallel with its axis. The data were compared with numerical results obtained by computer simulation, under the assumption of spatial dependent acoustic impedance and phase velocity, leading to the conclusion that the Young modulus is affected by the magnetoelastic interaction according to a linear decrease.