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排序方式: 共有1243条查询结果,搜索用时 15 毫秒
91.
92.
Charmasson S Le Faouder A Loyen J Cosson RP Sarradin PM 《The Science of the total environment》2011,409(4):771-777
The hydrothermal deep-sea vent fauna is naturally exposed to a highly specific environment enriched in potentially toxic species such as sulfides, metals and natural radionuclides due to the convective seawater circulation inside the oceanic crust and its interaction with basaltic or ultramafic host rocks. However, data on radionuclides in biota from such environment are very limited. An investigation was carried out on tissue partitioning of 210Po and 210Pb, two natural radionuclides within the 238U decay chain, in Bathymodiolus azoricus specimens from the Mid-Atlantic Ridge (Menez Gwen field). These two elements showed different distributions with high 210Pb levels in gills and high 210Po levels in both gills and especially in the remaining parts of the body tissue (including the digestive gland). Various factors that may explain such partitioning are discussed. However, 210Po levels encountered in B. azoricus were not exceptionally high, leading to weighted internal dose rate in the range 3 to 4 μGy h− 1. These levels are slightly higher than levels characterizing coastal mussels (~ 1 μGy h− 1). 相似文献
93.
Roxane Detry Vera Van Hoed Jérôme Sterckx Catherine Deledicque Kiyotaka Sato Christophe Blecker Sabine Danthine 《European Journal of Lipid Science and Technology》2021,123(1):2000155
Developing trans-free alternative fat solutions suitable for specific applications remains a challenge in edible fats and other domains. This is particularly true for palm oil-based puff pastry margarines, which suffer from post crystallization problems, leading to dramatic loss of functionality. This research is aimed at investigating the influence of triacylglycerol (TAG) compositions of palm oil-based puff pastry margarines on the physical properties of the fat crystal network, which determine the functionality of such products. Three model puff pastry margarines are produced at pilot scale under the same crystallization conditions. They share the same fatty acid composition and close solid fat content (SFC) profiles, whereas the proportions of major TAG (tripalmitoylglycerol (PPP), 1,3-di-palmitoyl-2-oleoylglycerol (POP), 1,2-di-palmitoyl-3-oleoylglycerol (PPO), 1,2-dioleoyl-3-palmitoylglycerol (POO)) are different. Polymorphism, melting profile, hardness, microscopic structures, and baking performance (puffing effect) of the model fats are examined during a period of 6 months. The following results are obtained: 1) The TAG composition significantly influences the post crystallization processes occurring in palm oil-based margarines. 2) High amounts of POP show negative influences. 3) The proportions of POP, PPO, and PPP should be carefully balanced to prevent detrimental crystal network rearrangements, leading to textural modifications (hardness increase) and significant reduction in baking performance. Practical Applications : The results presented in this work could be helpful for edible fat products developers, especially for roll-in fat applications. This research provides an overview of the relevant properties to study for the assessment of puff pastry margarine functionality. It also highlights the importance of ensuring long-term stability of palm oil-based fat products. Finally, it emphasizes that certain combinations of fat materials should be avoided to maintain the quality of palm oil-based puff pastry margarines. 相似文献
94.
Katharina Nekolla Sabine Sellner Marc Praetner Karina Mildner Dagmar Zeuschner Fritz Krombach 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(14):1882-1890
So‐called membrane nanotubes are cellular protrusions between cells whose functions include cell communication, environmental sampling, and protein transfer. It has been previously reported that systemically administered carboxyl‐modified quantum dots (cQDs) are rapidly taken up by perivascular macrophages in skeletal muscle of healthy mice. Expanding these studies, it is found, by means of in vivo fluorescence microscopy on the mouse cremaster muscle, rapid uptake of cQDs not only by perivascular macrophages but also by tissue‐resident cells, which are localized more than 100 μm distant from the closest vessel. Confocal microscopy on muscle tissue, immunostained for the membrane dye DiI, reveals the presence of continuous membranous structures between MHC‐II‐positive, F4/80‐positive cells. These structures contain microtubules, components of the cytoskeleton, which clearly colocalize with cQDs. The cQDs are exclusively found inside endosomal vesicles. Most importantly, by using in vivo fluorescence microscopy, this study detected fast (0.8 μm s?1, mean velocity), bidirectional movement of cQDs in such structures, indicating transport of cQD‐containing vesicles along microtubule tracks by the action of molecular motors. The findings are the first to demonstrate membrane nanotube function in vivo and they suggest a previously unknown route for the distribution of nanomaterials in tissue. 相似文献
95.
96.
Maria Immaculata Arifin Samia Hannaoui Sheng Chun Chang Simrika Thapa Hermann M. Schatzl Sabine Gilch 《International journal of molecular sciences》2021,22(5)
Chronic wasting disease (CWD) is a prion disease found in both free-ranging and farmed cervids. Susceptibility of these animals to CWD is governed by various exogenous and endogenous factors. Past studies have demonstrated that polymorphisms within the prion protein (PrP) sequence itself affect an animal’s susceptibility to CWD. PrP polymorphisms can modulate CWD pathogenesis in two ways: the ability of the endogenous prion protein (PrPC) to convert into infectious prions (PrPSc) or it can give rise to novel prion strains. In vivo studies in susceptible cervids, complemented by studies in transgenic mice expressing the corresponding cervid PrP sequence, show that each polymorphism has distinct effects on both PrPC and PrPSc. It is not entirely clear how these polymorphisms are responsible for these effects, but in vitro studies suggest they play a role in modifying PrP epitopes crucial for PrPC to PrPSc conversion and determining PrPC stability. PrP polymorphisms are unique to one or two cervid species and most confer a certain degree of reduced susceptibility to CWD. However, to date, there are no reports of polymorphic cervid PrP alleles providing absolute resistance to CWD. Studies on polymorphisms have focused on those found in CWD-endemic areas, with the hope that understanding the role of an animal’s genetics in CWD can help to predict, contain, or prevent transmission of CWD. 相似文献
97.
98.
Marc J. Ledoux Cuong Pham-Huu Nicolas Keller Jean-B. Nougayr de Sabine Savin-Poncet Jacques Bousquet 《Catalysis Today》2000,61(1-4):157-163
Very high activity and selectivity could be achieved for the direct oxidation of H2S into elemental sulfur at low reaction temperature (40–60°C), on nickel sulfide supported SiC catalyst. The heterogeneous nature of the support surface (hydrophilic and hydrophobic areas) could explain the important role played by water to maintain a high and stable H2S conversion level. The formation of a very active superficial nickel oxysulfide phase was proposed in order to explain the activation period necessary at reaction temperatures <60°C. Total selectivity for sulfur was attributed to the very low reaction temperature and the absence of any microporosity in the support. 相似文献
99.
We consider supplier-credit contracting between a manufacturer and a liquidity-constrained dealer. We show that the timeliness according to which the dealer receives demand information has a significant impact on the optimal contract. If the manufacturer cannot be sure that a dealer without liquidity has demand information when the contract is written, the optimal contract assigns the same quantity to an ignorant dealer and a dealer who knows that there are unfavorable demand conditions. However, dealers with favorable demand information are screened. If the dealer??s liquidity rises, the manufacturer proposes a contract that resembles the solution of a classic adverse selection model in the spirit of Harris et?al. (Manag Sci 28:604?C620, 1982). For high liquidity, the optimal supplier-credit contract assigns the same quantity to an ignorant dealer and dealers who have favorable demand information whereas dealers with unfavorable demand information are screened. 相似文献
100.
Nadja Straue Martin Rauscher Sabine Walther Hendrik Faber Andreas Roosen 《Journal of Materials Science》2009,44(22):6011-6019
The production of printed electronics exhibits an enormous economical potential due to the possibility to manufacture innovative
products at low cost. At the moment, one of the major challenges for the fabrication of printed electronics is the controllability
of the material properties during processing and the miniaturization of the deposited structures. In this context, the application
of soft lithographic techniques appears promising, because they allow a defined patterning of the materials in the range of
few nanometers, which is far below the limits of other printing techniques like inkjet-printing or screen printing. This work
proves the applicability of the soft lithographic technique micro-molding in capillaries (MIMIC) for the manufacture of conductive
indium tin oxide (ITO) electrodes. For the creation of stable dispersions of ITO nano-sized particles, steric as well as electrostatic
stabilization concepts are applied. The prepared dispersions are characterized with regard to the later processing via MIMIC.
The geometry and the electrical properties of the soft lithographically deposited structures are determined to prove their
functionality. Special attention is paid to the influence of the wetting behavior of the dispersions on the resulting geometry
of the structures. Finally, the applicability of the optimized structures is demonstrated by the assembly of a thin film transistor
(TFT), in which the deposited structures serve as source and drain electrodes. 相似文献