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121.
Andrés F Cubillos Bojacá María C García Muñoz Ana M Calvo Salamanca Guillermo H Carvajal Rojas Martha P Tarazona-Díaz 《Journal of the science of food and agriculture》2019,99(13):i-i
The cover image is based on the Research Article Study of the physical and chemical changes during the maturation of three cocoa clones, EET8, CCN51, and ICS60 by Andrés F Cubillos Bojacá et al., DOI: 10.1002/jsfa.9882 . Cover image ©AGROSAVIA Images.
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123.
Martha Hernández-Orta Elías Pérez Luis Emilio Cruz-Barba Marco A. Sánchez-Castillo 《Journal of Materials Science》2018,53(12):8766-8785
Plasma-based technology is an alternative to produce universal polymer coatings with the appropriate requirements of robustness and stability for antibacterial applications. Here, we proposed a sequential two-step alternative to synthesize antibacterial polymer coatings. A non-isothermal plasma reactor, operated at atmospheric pressure (Patm) and room temperature (Troom), was used to induce free radical polymerization of 4-vinyl pyridine (4VP) on high-density polyethylene (PE). In a subsequent step, the poly-4VP (P4VP) films were treated with a bromoethane/He gas stream to produce quaternized P4VP (P4VPQ) films. Chemical structure of polymer films was validated by infrared and UV–visible spectroscopy, and morphology was evaluated by optical and atomic force microscopy; scanning electron microscopy was used to determine films thickness, which was then used to estimate the surface charge density. The bactericidal capacity was determined with a standard test by using Escherichia coli. Both types of films had an estimated charge density in the order of 1016 positive charges per cm2; P4VP films removed about 95–99% of bacteria, whereas 4PVPQ films eliminated 100%. The methodology proposed for the synthesis of antibacterial polymer coatings is simpler, faster, and more environmentally friendly than other plasma-based methods; operation at Troom and Patm may also have a significant effect on the economics and the ease of implementation of the process at commercial scale. The suggested approach may facilitate the development of new universal coatings, and operating plasma conditions could be extrapolated for engineering antibacterial coatings in industrial areas where bacterial attachment is of concern. 相似文献
124.
Martha L. Carlson Mazur Jeff Schaeffer Jennifer E. Granneman Natalie Goldstrohm Faith A. Fitzpatrick James H. Larson Paul C. Reneau Kurt P. Kowalski Paul W. Seelbach 《Journal of Great Lakes research》2019,45(3):651-663
Rivermouth ecosystems in the Laurentian Great Lakes represent complex hydrologic mixing zones where lake and river water combine to form biologically productive areas that are functionally similar to marine estuaries. As urban, industrial, shipping, and recreational centers, rivermouths are the focus of human interactions with the Great Lakes and, likewise, may represent critical habitat for larval fish and other biota. The hydrology and related geomorphology in these deltaic systems form the basis for ecosystem processes and wetland habitat structure but are poorly understood. To this end, we examined hydrogeomorphic structure and lake-tributary mixing in three rivermouths of intermediate size using water chemistry, stable isotopes, and current profiling over a five-month period. In rivermouths of this size, the maximum depth of the rivermouth ecosystem influenced water mixing, with temperature-related, density-dependent wedging and layering that isolated lake water below river water occurring in deeper systems. The inherent size of the rivermouth ecosystem, local geomorphology, and human modifications such as shoreline armoring and dredging influenced mixing by altering the propensity for density differences to occur. The improved scientific understanding and framework for characterizing hydrogeomorphic processes in Great Lakes rivermouths across a disturbance gradient is useful for conservation, management, restoration, and protection of critical habitats needed by native species. 相似文献
125.
The biological activity, including metabolism and modulation of ornithine decarboxylase activity and DNA synthesis, of arachidonic
acid (AA) and eicosapentaenoic acid (EPA) were compared in epidermal cells from SENCAR mice. Radiolabelled AA and EPA were
found to be similarly incorporated into and released from membrane phospholipids of unstimulated cultures. However, when cells
were stimulated with the tumor promoter 12-0-tetradecanoylphorbol-13-acetate (TPA), the release of AA was significantly higher
than the release of EPA. The extent of metabolism of AA and EPA to prostaglandins was determined in both freeze-thawed cell
preparations and in viable cultured cells. In the freeze-thawed preparations, use of AA as a substrate resulted in significantly
more PGF than when EPA was used as the substrate. However, more PGE3 was formed than PGE2. PGD levels were the same for either fatty acid precursor. Prostaglandin production was also determined in viable cultured
cells since other influences such as phospholipase A2 activity can modify prostaglandin production. Control cultures prelabelled with either AA or EPA produced similar amounts
of the respective PGF, PGE, and PGD. However, TPA-stimulated cultures produced significantly higher amounts of each prostaglandin
in cultures prelabelled with AA compared to cells prelabelled with EPA. HETE or HEPE production was the same both for cultured
cells prelabelled with AA or EPA and for homogenates from uncultured cells incubated directly with the radiolabelled fatty
acids. TPA-induced ornithine decarboxylase (ODC) was significantly higher in AA-treated cultures compared to EPA-treated cultures.
AA supports DNA synthesis to a greater extent than EPA, either alone or in the presence of TPA. These findings suggest that
AA and EPA do not have equivalent biological activity in mouse epidermal cells. 相似文献
126.
Cynomolgus monkeys were fed oils high in linoleic acid or with half of the linoleic acid replaced by either (n−3) linolenic
acid or marine fatty acids. When the diet contained similar quantities of linoleic and (n−3) linolenic acid, erythrocyte fatty
acids maintained a ratio of (n−6) to (n−3) fatty acids of approximately 2∶4. Fatty acids from menhaden oil enhanced the incorporation
of eicosapentaenoic and docosahexaenoic acids into the monkey erythrocytes, the composition of which was not altered by additional
α-tocopherol. 相似文献
127.
David Kok Shikhar Krishn Jha Rishi Raj Martha L. Mecartney 《Journal of the American Ceramic Society》2017,100(7):3262-3268
Three‐phase ceramic composites constituted from equal volume fractions of α‐Al2O3, MgAl2O4 spinel, and cubic 8 mol% Y2O3‐stabilized ZrO2 (8YSZ) were flash‐sintered under the influence of DC electric fields. The temperature for the onset of rapid densification (flash sintering) was measured using a constant heating rate at fields of 50‐500 V/cm. The experiments were carried out by heating the furnace at a constant rate. Flash sintering occurred at a furnace temperature of 1350°C at a field of 100 V/cm, which dropped to 1150°C at a field of 500 V/cm. The sintered densities ranged from 90% to 96%. Higher electric fields inhibited grain growth due to the lowering of the flash temperature and an accelerated sintering rate. During flash sintering, alumina reacted with the spinel phase to form a high‐alumina spinel solid solution, identified by electron dispersive spectroscopy and from a decrease in the spinel lattice parameter as measured by X‐ray diffraction. It is proposed that the solid solution reaction was promoted by a combination of electrical field and Joule heating. 相似文献
128.
Dawid Stawski Priyanka Sahariah Martha Hjálmarsdóttir Dorota Wojciechowska Michał Puchalski Már Másson 《纺织学会志》2017,108(6):1041-1049
The paper presents a method of depositing N,N,N-trimethyl chitosan (TMC) layers onto polypropylene and polylactide nonwovens. A two-step modification procedure is applied: first, grafting the nonwovens with acrylic acid and next layer-by-layer deposition. Turbidimetric measurements confirm the creation of polycomplexes between grafted poly(acrylic acid) and deposited TMC. The created material structure is evaluated using gravimetric analysis, reflectance Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy measurements and pH-metric titration. The modified material exhibits good antibacterial properties against Gram-positive bacteria Staphylococcus aureus. 相似文献
129.
130.
The toxicities to marine animals of nine oil dispersants, three oil emulsions with Corexit and of a dispersion of Oman crude oil, have been studied in continuous flow aquarium systems at 96-h exposures followed by a recovery period in clean sea-water. New types of dispersants were found to be less toxic than older types and oil emulsions more toxic than dispersants alone or crude oil alone. Fishes and bivalves were found most sensitive. Crustaceans were the most resistant to dispersants but very susceptible to oil emulsions. The tolerance of different species was found to be related to their mode of life, more active species being more susceptible. Delayed mortality of bivalves increased their susceptibility if the recovery period was included. Effects on locomotory behaviour of fishes and crustaceans, breathing rate of fish, valve-closure of bivalves and byssal thread formation of common mussels have been demonstrated for both dispersants and oil emulsions. The general sequence of such effects was: increased activity; successively impaired activity; immobilization; and death. Recovery is good for fish and crustaceans but poor for bivalves due to the delayed effects. Ecological consequences of dispersants and oil pollution in the marine environment are discussed. 相似文献