Autoproteolytic fragments are intermediates in the oligomerization/aggregation of the Parkinson's disease protein alpha-synuclein as revealed by ion mobility mass spectrometry

Gas-phase protein separation by ion mobility: With its ability to separate the Parkinson's disease protein α-synuclein and its autoproteolytic products-despite the small concentrations of the latter-ion-mobility MS has enabled the characterization of intermediate fragments in in vitro oligomerization-aggregation. In particular, a possible key fragment, the highly aggregating C-terminal fragment, αSyn(72-140), has been revealed.     

On‐line LC‐NMR‐MS characterization of sesame oil extracts and assessment of their antioxidant activity

Sesame lignans were isolated by solvent extraction and subsequently purified by solvent crystallization from crude, unroasted sesame oil, and a sesame oil deodorizer distillate. In addition, an aliquot of the purified sesame oil extract was treated with camphorsulfonic acid to obtain a sesaminol‐enriched extract. The sesame lignan composition of the extracts was characterized by on‐line liquid chromatography nuclear magnetic resonance spectroscopy mass spectrometry coupling (LC‐NMR‐MS). The effect of the sesame oil extracts as well as pure sesame lignans and γ‐tocopherol on the oxidative stability of sunflower oil (lignan‐free) was studied by the Rancimat assay. The Rancimat assay revealed the following oxidative stability order: sesame oil extract < sesame oil deodorizer distillate < sunflower oil (no added sesame oil extracts) < sesamol < sesaminol‐enriched sesame oil extract. In addition, the radical‐scavenging capacity of these extracts was assessed by the Trolox® equivalent antioxidant capacity (TEAC) assay. The TEAC assay revealed a slightly different AOX activity order: sesamin < sesame oil extract < sesaminol‐enriched sesame oil extract < sesamol. In conclusion, the sesaminol‐enriched extract revealed strong antioxidant activity and is therefore suitable to increase the oxidative stability of edible oils high in polyunsaturated fatty acids.     

Orientational order and mechanical properties of poly(amide-block-aramid) alternating block copolymer films and fibers

Mechanical properties and orientational order of a series of uniaxially oriented block copolymer films and fibers comprised of alternating rigid aramid blocks of poly(p-phenylene terephthalamide) (PPTA) and flexible blocks of polyamide 6,6 (PA 6,6) have been investigated. The prepared block copolymer films differ in aramid content and average block length. The films were prepared by shearing the polymer solutions (in sulphuric acid) followed by rapid coagulation of the solutions in water. From wide angle X-ray scattering (WAXS) and optical polarisation microscopy (OPM) it was found that films with a mole fraction of PPTA of at least 0.5 show a liquid crystalline (LC) phase. It was found that the mechanical properties of LC block copolymer films are similar to the properties of isotropic films, as determined with dynamical mechanical analyses (DMAs) and from tensile tests. This was attributed to the relative low parameter of the LC films obtained by using WAXS. Copolymerisation of the PPTA blocks with the flexible polyamide blocks resulted in an increase of storage and Young's modulus, a decrease of the elongation at break while the tensile strength was unaffected compared to normal PA 6,6. Block copolymer fibers have been spun from liquid crystalline solutions by means of a dry-jet wet spinning process. The only variable parameter was the imposed draw-ratio in the air-gap of the spinning process. Increasing the draw-ratio resulted in an increased molecular orientation, Young's modulus and tensile strength of the fibers while its effect on the maximum elongation at break was small. Heat treatment at 300 °C of the fibers resulted in an increase of the Young's modulus, a minor increase of the strength and a decrease of the elongation at break. Scanning electron microscopic (SEM) photographs of the fractured surfaces of the block copolymer fibers do not show a fibrillar fracture surface, which is typically observed for pure PPTA fibers.     

Phase Characterization of High Basicity Manganese Slags

Slag chemistry applied in the AlloyStream process differs from that used in the production of high carbon ferromanganese in the submerged arc furnace. In process development of the AlloyStream process, several pilot plant and demonstration plant campaigns were completed. Slag samples were selected from the samples collected at each tap, throughout the four month pilot plant campaign. Phase characterization of these samples is reported here, and the results are interpreted in terms of the slag chemistry operational options in the AlloyStream process.     

Development of a Reliable Kinetic Model for Ladle Refining

Metallurgical and Materials Transactions B - Kinetic modeling of ladle refining can be used by steel plants to improve steelmaking and to produce cleaner steels. It can also help researchers to...     

1H‐ and 13C‐NMR spectroscopic study of chemical equilibria in the system acetaldehyde + water

Acetaldehyde is an important intermediate in the chemical industry and often used in mixtures with water. These mixtures are reactive multicomponent systems, as acetaldehyde forms oligomers with water. Quantitative studies of the resulting speciation are scarce in the literature and limited to the formation of the smallest oligomer, ethane‐1,1‐diol. Therefore, in the present work, a comprehensive study of chemical equilibria in mixtures of acetaldehyde and water was carried out by quantitative ¹H‐ and ¹³C‐NMR spectroscopy. The study covers temperatures between 275 and 338 K and overall acetaldehyde mole fractions between about 0.05 and 0.95 mol/mol. The peak assignment is given for both the ¹H‐ and ¹³C‐NMR spectra. From the speciation data, obtained from the peak area fractions, numbers for the chemical equilibrium constants of the oligomer formation are obtained and a correlation is presented. © 2014 American Institute of Chemical Engineers AIChE J, 61: 177–187, 2015     

Heterogeneous Teams of Modular Robots for Mapping and Exploration

In this article, we present the design of a team of heterogeneous, centimeter-scale robots that collaborate to map and explore unknown environments. The robots, called Millibots, are configured from modular components that include sonar and IR sensors, camera, communication, computation, and mobility modules. Robots with different configurations use their special capabilities collaboratively to accomplish a given task. For mapping and exploration with multiple robots, it is critical to know the relative positions of each robot with respect to the others. We have developed a novel localization system that uses sonar-based distance measurements to determine the positions of all the robots in the group. With their positions known, we use an occupancy grid Bayesian mapping algorithm to combine the sensor data from multiple robots with different sensing modalities. Finally, we present the results of several mapping experiments conducted by a user-guided team of five robots operating in a room containing multiple obstacles.     

Effects of increasing internal end-point temperatures on physicochemical and sensory properties of meat: A review

Although many efforts have been made to improve and control the eating quality of meat, there is still high variability in palatability, which may ultimately result in customer dissatisfaction. Beef meat is especially intricate to study since consumers have specific preferences for degrees of doneness. The degrees of doneness in beef is known to affect its physicochemical properties and have a subsequent effect on palatability. Nevertheless, an in-depth investigation into the exact changes that occur with increasing internal end-point temperatures of meat is yet to be explored. With researchers implementing various cooking methods and cooking conditions (i.e., sample preparation and internal end-point temperatures), the results of studies are often impossible to compare. This review provides an overview of the various benefits and drawbacks of the cooking methods commonly used at home, in commercial enterprises, and research on meat. Furthermore, the physicochemical changes in meat with increasing degrees of doneness are discussed in detail with considerations of the subsequent changes in the sensory properties of meat.