Isolation and characterization of ganglioside 9-O-acetyl-GD3 from bovine buttermilk

Bovine buttermilk contains a unique ganglioside, 9-O-acetyl-GD₃. In order to isolate large quantities of this ganglioside, a simplified isolation scheme which consists of several ion-exchange and silica gel column chromatographic procedures was devised. The isolated 9-O-acetyl-GD₃ was characterized on the basis of its thin-layer chromatographic behavior, its immunoreactivity with a specific monoclonal antibody, JONES, and by conversion to authentic GD₃ by mild base treatment.     

A model for studying LCAT reaction: In vitro cholesterol esterification in pig ovarian follicular fluid

Phosphatidylcholine acyltransferase (lecithin:cholesterol acyltransferase or LCAT; EC 2.3.1.43) activity was found to be present in pig ovarian follicular fluid (POFF), in addition to pig serum (PS). The cholesterol esterification rate in both POFF and PS is linear with incubation time up to 2 hr. The mean absolute rate of POFF-cholesterol esterification was 8.1±0.4 nmoles per ml per hr approximately one-fourth of that in PS. However, the fractional rate (percent of labeled cholesterol esterified per hr) of POFF-cholesterol esterification was similar to that observed in PS. There was little variation of absolute rate of cholesterol esterification in the fluid obtained from different sizes of follicles. Fatty acid or triacylglycerol did not participate in the reaction of cholesterol esterification in POFF. No appreciable change in enzymatic activity was found from storing POFF at 4 C for periods of time up to 24 hr or at −70 C up to 2 months, but activity was lost thereafter. On the other hand, PS showed a much longer period of stability (5 days at 4 C and 9 months at −70 C). A discrepancy between the fatty acid composition of cholesteryl esters formed by the LCAT reaction and the fatty acid composition at the C-2 position of phosphatidylcholine led us to propose a two-step mechanism for the LCAT reaction. It is concluded that the LCAT of POFF, as well as that of plasma, is specific for individual fatty acids rather than for the fatty acid composition of phosphatidylcholine. The fatty acid concentration of lysophosphatidylcholine decreased during prolonged incubation times (6 to 21 hr) suggesting that the increased lysophosphatidylcholine formed as a product of the LCAT reaction may be reused as substrate for the LCAT reaction or for hydrolysis by lysophosphatidylcholine hydrolase. Presented at the AOCS Meeting, New York, May 1977.     

Microstructure of high modulus solid state extruded polyethylene: 2. X-ray scattering studies of 12, 24 and 36 extrusion draw ratio

The microstructure of a series of solid state extruded polyethylene fibres was examined by wide- and small-angle X-ray scattering. By measuring absolute intensities using a two dimensional position sensitive detector, accurate values of the small-angle invariant for anisotropic samples were obtained. This measurement coupled with wide-angle X-ray scattering and d.s.c. permitted determination of the density of the noncrystalline component. The use of a two phase model for solid state extruded polyethylene is justified if consideration is given to the effective densities of the crystalline and noncrystalline phases, which change with deformation. The effective density of the crystalline phase decreases by 1% (0.999–0.990 g cm^?3) from the unextruded billet compared to a 36 draw ratio extrudate, while the noncrystalline phase density increases by 6% (0.84–0.89 g cm^?3). These changes lead to an overall decrease in the mean squared electron density fluctuation of 63%. The average axial crystallite length measured by wide-angle X-ray scattering increases with extrusion draw ratio while the SAXS long period decreases and weakens considerably. These observations and the electron microscopy results from the previous paper, (Polymer, 1982, 23, 1069), are fully consistent with the key features of the Peterlin model of fibre microstructure.     

Radical entry mechanisms in redox-initiated emulsion polymerizations

The mechanisms and kinetics of radical entry in emulsion polymerizations utilizing redox initiation are investigated using polymerization rate data obtained by reaction calorimetry and electrospray mass spectroscopy analysis of initiator-derived aqueous-phase products. These data have been used to evaluate an initiation scheme for redox-initiated emulsion polymerizations of common monomers such as styrene and methyl methacrylate based around the oxidant, tert-butyl hydroperoxide. Redox initiators are broadly classed by the solubility of their radical products: Hydrophilic radicals enter by propagating to a critical degree of polymerization to become surface-active whilst more hydrophobic radicals may enter particles directly. When direct entry is applicable (the hydrophobic case), initiation efficiency will always be very high.     

Fluorescence of poly(di-n-alkylsilane)s in room-temperature solution

A comprehensive study of the electronic absorption and emission spectra and the fluorescence quantum yield and lifetime of seven poly(di-n-alkylsilane)s and of three isotopically labelled poly(di-n-hexylsilane)s in hydrocarbon solution at room temperature is reported. Also reported are fluorescence polarization and carbon tetrachloride quenching of fluorescence of poly(di-n-hexylsilane). The observed fluorescence spectra, quantum yield, and polarization depend on the selected excitation energy in a very characteristic fashion, whereas the fluorescence lifetime does not; however, it depends on the selected emission energy. These characteristic dependencies are qualitatively accounted for by the previously proposed segment distribution model if one assumes that the photophysical behavior at higher excitation energies is strongly affected by the presence of a low-lying weakly allowed state in short-segment chromophores and the behavior at lower excitation energies is dictated by the selective excitation of emitting long-segment chromophores.     

Study of UAV tracking based on CNN in noisy environment

Multimedia Tools and Applications - Recently, there are lots of tracking methods proposed to improve the performance of visual tracking in videos with challenging situations, such as background...     

A high-temperature oxidation-resistant Fe-Mn-Al-Si alloy

To develop satisfactory alloys without Cr or Ni for high-temperature application up to 1100C, three alloys based on Fe-10%Al-Si with differing fourth (or fifth) element additions were oxidized in air at 1100°Cfor 24 hr. A low carbon, Fe-30Mn-10Al-Si alloy exhibited excellent high-temperature oxidation resistance. The total weight gain for 24 hr oxidation in air at 1100°C was only 1.03 mg/cm ². After air oxidation for 6 days at 1100°C, no nodule formation or breakthrough oxidation occurred. Post-oxidation SEM and EDAX examination showed that a thin, compact, protective alumina scale formed on the alloy.Visiting Scientist (People's Republic of China).     

Thermal spraying of biomaterials

Osteoconductive hydroxyapatite coatings for metallic endoprostheses for hip and knee joint replacement provide a state-of-the-art template for enhanced in-growth of bone cells. However, the high temperature of the plasma jet leads to large scale dehydroxylation and decomposition of the starting powder. A model is being developed to explain the formation of chemically and mechanically inhomogeneous porous calcium phosphate coatings deposited by atmospheric plasma spraying onto titanium alloy substrates. In addition the biofunctionality is being discussed of titania bond coats and their influence on the in vivo performance of hydroxyapatite-titania duplex coating systems.     

Production of niobium powder by magnesiothermic reduction of niobium oxides in a cyclone reactor

In the last years, a variety of processes respectively process steps have been investigated for the production of niobium powder. This is due to the fact that niobium capacitors could be a viable alternative to tantalum capacitors from a performance, availability, and price point of view. The reduction of niobium pentoxide by magnesium results in fine powders with high specific surface area but has the disadvantages of a very exothermic nature and the formation of magnesium niobate. It is shown in this work that the application of a continuously operating cyclone reactor and the use of niobium(IV) oxide as raw material solve these problems. A good control of the highly exothermic reaction within the cyclone reactor was achieved in the cyclone reactor by the ratio between gas flow rate and powder flow rate as well as by a proper preheating of the gas.     

Debugging mixed‐environment programs with Blink

Programmers build large‐scale systems with multiple languages to leverage legacy code and languages best suited to their problems. For instance, the same program may use Java for ease of programming and C to interface with the operating system. These programs pose significant debugging challenges, because programmers need to understand and control code across languages, which often execute in different environments. Unfortunately, traditional multilingual debuggers require a single execution environment. This paper presents a novel composition approach to building portable mixed‐environment debuggers, in which an intermediate agent interposes on language transitions, controlling and reusing single‐environment debuggers. We implement debugger composition in Blink, a debugger for Java, C, and the Jeannie programming language. We show that Blink is (i) simple: it requires modest amounts of new code; (ii) portable: it supports multiple Java virtual machines, C compilers, operating systems, and component debuggers; and (iii) powerful: composition eases debugging, while supporting new mixed‐language expression evaluation and Java native interface bug diagnostics. To demonstrate the generality of interposition, we build prototypes and demonstrate debugger language transitions with C for five of six other languages (Caml, Common Lisp, C#, Perl 5, Python, and Ruby) without modifications to their debuggers. Using real‐world case studies, we show that diagnosing language interface errors require prior single‐environment debuggers to restart execution multiple times, whereas Blink directly diagnoses them with one execution. Copyright © 2014 John Wiley & Sons, Ltd.