Improved Extraction and Sample Cleanup of Tri-glycoalkaloids α-Solanine and α-Chaconine in Non-denatured Potato Protein Isolates

Glycoalkaloids in potato-derived products result in bitter taste and potentially toxic effects at high intakes. Generally, extraction of glycoalkaloids prior to HPLC analysis is carried out by dilute acetic acid. For most potato-derived extracts including heat-coagulated potato proteins, this extraction method is sufficient to achieve satisfying tri-glycoalkaloid (TGA) recoveries. Soluble potato proteins obtained by non-denaturing processes show different requirements for glycoalkaloid extraction. TGA extraction was optimized for two commercially available native potato protein isolates and compared to heat-coagulated potato protein. The highest TGA levels were determined in the extract when extraction was carried out at 40 °C by at least 5 % acetic or propionic acid supplemented with 20 mM Na-1-heptanesulfonate (HSA). Addition of HSA results in substantially improved TGA extraction and induces precipitation of soluble protein which enhanced sample cleanup. On the contrary, extraction of TGA from coagulated potato protein in the presence of HSA showed a reduced TGA extraction efficiency. This improved TGA extraction procedure for soluble non-denatured potato protein isolates results in reliable quantification of bitter tasting and toxic glycoalkaloid levels. This contributes to a non-bitter and safe use of the nutritional and functional benefits of this plant protein in food applications.     

Controlling micro‐ and nanofibrillar morphology of polymer blends in low‐speed melt spinning process. Part II: Influences of extrusion rate on morphological changes of a PLA/PVA blend through a capillary die

The effects of the extrusion rate on the morphological changes of poly(lactic acid) (PLA)/poly(vinyl alcohol) (PVA) blend through a capillary die were investigated. In this study, the extrusion rate or mass flow rate is altered from 0.5 g min^?1 to 2 g min^?1 with an increment of 0.5 g min^?1. The PLA/PVA blend with a composition of 30/70 (wt %) exhibits a particle matrix morphology with dispersed PLA droplets within the PVA matrix. It is found that, the spherical or ellipsoidal dispersed PLA droplets are elongated and coalesced into rod‐like or longer ellipsoidal droplets when they pass through the capillary die. When the extrusion rate increases, the coalescence between the large PLA droplets occurs more intense. However, the changes of the extrusion rate have no strong effect on the coalescence of small droplets having diameter less than about 150 nm. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44257.     

Melt spun matrix fibers of toughened polypropylene copolymers modified by high energy electrons

Binary blends of polypropylene (PP) and ethylene‐octene copolymer (EOC) are prepared by continuous electron‐induced reactive processing at various mass ratios of the blend components and various doses without adding of any grafting agents. The influence of mass ratio and dose is investigated in order to get the optimum processing behavior of toughened PP as well as optimum properties of resulting fibers. It is found that toughened PP with a PP/EOC blend ratio of 97.5–2.5  mass % can be used advantageously as a matrix component for the process of online spinning of glass fiber/toughened PP hybrid yarns. Such hybrid yarns belong to one of the most advanced production methods for the manufacturing of fiber reinforced thermoplastic composites with an increased mechanical performance. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44011.     

11C‐ and 18F‐Labeled Radioligands for P‐Glycoprotein Imaging by Positron Emission Tomography

P‐Glycoprotein (P‐gp) is an efflux transporter widely expressed at the human blood–brain barrier. It is involved in xenobiotics efflux and in onset and progression of neurodegenerative disorders. For these reasons, there is great interest in the assessment of P‐gp expression and function by noninvasive techniques such as positron emission tomography (PET). Three radiolabeled aryloxazole derivatives: 2‐[2‐(2‐methyl‐(¹¹C)‐5‐methoxyphenyl)oxazol‐4‐ylmethyl]‐6,7‐dimethoxy‐1,2,3,4‐tetrahydroisoquinoline ([¹¹C]‐ 5 ); 2‐[2‐(2‐fluoromethyl‐(¹⁸F)‐5‐methoxyphenyl)oxazol‐4‐ylmethyl]‐6,7‐dimethoxy‐1,2,3,4‐tetra‐hydroisoquinoline ([¹⁸F]‐ 6 ); and 2‐[2‐(2‐fluoroethyl‐(¹⁸F)‐5‐methoxyphenyl)oxazol‐4‐ylmethyl]‐6,7‐dimethoxy‐1,2,3,4‐tetrahydroisoquinoline ([¹⁸F]‐ 7 ), were tested in several in vitro biological assays to assess the effect of the aryl substituent in terms of potency and mechanism of action toward P‐gp. Methyl derivative [¹¹C]‐ 5 is a potent P‐gp substrate, whereas the corresponding fluoroethyl derivative [¹⁸F]‐ 7 is a P‐gp inhibitor. Fluoromethyl compound [¹⁸F]‐ 6 is classified as a non‐transported P‐gp substrate, because its efflux increases after cyclosporine A modulation. These studies revealed a promising substrate and inhibitor, [¹¹C]‐ 5 and [¹⁸F]‐ 7 , respectively, for in vivo imaging of P‐gp by using PET.     

Filler Wetting in Miscible ESBR/SSBR Blends and Its Effect on Mechanical Properties

The selective wetting behavior of silica in emulsion styrene butadiene rubber (ESBR)/solution styrene butadiene rubber (SSBR) blends is characterized by the wetting concept, which is further developed for filled blends based on miscible rubbers. It is found that not only the chemical rubber–filler affinity but also the topology of the filler surface significantly influences the selective filler wetting in rubber blends. The nanopore structure of the silica surface has been recognized as the main reason for the difference in the wetting behavior of the branched ESBR molecules and linear SSBR molecules. However, the effect of nanopore structure becomes more significant in the presence of silane. It is discussed that the adsorption of silane on silica surface constricts the nanopore to some extent that hinders effectively the space filling of the nanopores by the branched ESBR molecules but not by the linear SSBR molecules. As a result, in silanized ESBR/SSBR blends the dominant wetting of silica surface by the tightly bonded layer of SSBR molecules causes a low‐energy dissipation in the rubber–filler interphase. That imparts the low rolling resistance to the blends similar to that of a silica‐filled SSBR compound, while the ESBR‐rich matrix warrants the good tensile behavior, i.e., good abrasion and wear resistance of the blends.

     

Carbon nanotubes‐filled thermoplastic polyurethane–urea and carboxylated acrylonitrile butadiene rubber blend nanocomposites

This article reports the preparation and characterization of multiwalled carbon nanotubes (MWCNTs)‐filled thermoplastic polyurethane–urea (TPUU) and carboxylated acrylonitrile butadiene rubber (XNBR) blend nanocomposites. The dispersion of the MWCNTs was carried out using a laboratory two roll mill. Three different loadings, that is, 1, 3, and 5 wt % of the MWCNTs were used. The electron microscopy image analysis proves that the MWCNTs are evenly dispersed along the shear flow direction. Through incorporation of the nanotubes in the blend, the tensile modulus was increased from 9.90 ± 0.5 to 45.30 ± 0.3 MPa, and the tensile strength at break was increased from 25.4 ± 2.5 to 33.0 ± 1.5 MPa. The wide angle X‐ray scattering result showed that the TPUU:XNBR blends were arranged in layered structures. These structures are formed through chemical reactions of ? NH group from urethane and urea with the carboxylic group on XNBR. Furthermore, even at a very low loading, the high degree of nanotubes dispersion results in a significant increase in the electrical percolation threshold. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40341.     

Influence of a cyclic butylene terephthalate oligomer on the processability and thermoelectric properties of polycarbonate/MWCNT nanocomposites

The thermoelectric properties of melt-processed nanocomposites consisting of a polycarbonate (PC) thermoplastic matrix filled with commercially available carboxyl (–COOH) functionalized multi-walled carbon nanotubes (MWCNTs) were evaluated. MWCNTs carrying carboxylic acid moieties (MWCNT-COOH) were used due the p-doping that the carboxyl groups facilitate, via electron withdrawing from the electron-rich π-conjugated system. Preliminary thermogravimetric analysis (TGA) of MWCNT-COOH revealed that the melt-mixing was limited at low temperatures due to thermal decomposition of the MWCNT functional groups. Therefore, PC was mixed with 2.5 wt% MWCNT-COOH (PC/MWCNT-COOH) at 240 °C and 270 °C. In order to reduce the polymer melt viscosity, a cyclic butylene terephthalate (CBT) oligomer was utilized as an additive, improving additionally the electrical conductivity of the nanocomposites. The melt rheological characterization of neat PC and PC/CBT blends demonstrated a significant decrease of the complex viscosity by the addition of CBT (10 wt%). Optical and transmission electron microscopy (OM, TEM) depicted an improved MWCNT dispersion in the PC/CBT polymer blend. The electrical conductivity was remarkably higher for the PC/MWCNT-COOH/CBT composites compared to the PC/MWCNT-COOH ones. Namely, the PC/MWCNT-COOH/CBT processed at 270 °C exhibited the best values with electrical conductivity; σ = 0.05 S/m, Seebeck coefficient; S = 13.55 μV/K, power factor; PF = 7.60 × 10⁻⁶μW/m K⁻², and thermoelectric figure of merit; ZT = 7.94 × 10⁻⁹. The PC/MWCNT-COOH/CBT nanocomposites could be ideal candidates for large-scale thermal energy harvesting, even though the presently obtained ZT values are still too low for commercial applications.     

污泥作为污水厂内碳源的水解特性及工艺选择

随着各地污水厂出水水质对氮、磷要求的日益提高,强化脱氮除磷成为必然要求,但是我国多数污水厂由于多种原因导致进水碳源不足,尤其是进水SCOD、VFAs的匮乏,直接影响了生物脱氮除磷的效率,甚至不得已采用人工投加外碳源脱氮或者化学除磷方式以满足严格的出水氮、磷要求,但这无疑大大提高了污水厂的产泥率及运行成本.充分挖掘污水厂的“内碳源”,利用污泥水解产生VFAs,不仅能有效提高除磷脱氮效率,而且可以降低污水厂的污泥产量,是可持续的资源化技术.比较了初沉污泥和活性污泥的水解特性差异,介绍了污泥水解工艺的常用构型及参数选择,以及国内外一些成功的实施案例.     

Monte Carlo uncertainty quantification of the effective delayed neutron fraction

The applicability of Monte Carlo techniques, namely the Monte Carlo sensitivity method and the random-sampling method, for uncertainty quantification of the effective delayed neutron fraction β_eff is investigated using the continuous-energy Monte Carlo transport code, MCNP, from the perspective of statistical convergence issues. This study focuses on the nuclear data as one of the major sources of β_eff uncertainty. For validation of the calculated β_eff, a critical configuration of the VENUS-F zero-power reactor was used. It is demonstrated that Chiba's modified k-ratio method is superior to Bretscher's prompt k-ratio method in terms of reducing the statistical uncertainty in calculating not only β_eff but also its sensitivities and the uncertainty due to nuclear data. From this result and a comparison of uncertainties obtained by the Monte Carlo sensitivity method and the random-sampling method, it is shown that the Monte Carlo sensitivity method using Chiba's modified k-ratio method is the most practical for uncertainty quantification of β_eff. Finally, total β_eff uncertainty due to nuclear data for the VENUS-F critical configuration is determined to be approximately 2.7% with JENDL-4.0u, which is dominated by the delayed neutron yield of ²³⁵U.