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Toudic B Garcia P Odin C Rabiller P Ecolivet C Collet E Bourges P McIntyre GJ Hollingsworth MD Breczewski T 《Science (New York, N.Y.)》2008,319(5859):69-71
Numerous crystalline materials, including those of bioorganic origin, comprise incommensurate sublattices whose mutual arrangement is described in a superspace framework exceeding three dimensions. We report direct observation by neutron diffraction of superspace symmetry breaking in a solid-solid phase transition of an incommensurate host-guest system: the channel inclusion compound of nonadecane/urea. Strikingly, this phase transition generates a unit cell doubling that concerns only the modulation of one substructure by the other-an internal variable available only in superspace. This unanticipated pathway for degrees of freedom to rearrange leads to a second phase transition, which again is controlled by the higher dimensionality of superspace. These results reveal nature's capacity to explore the increased number of phases allowed in aperiodic crystals. 相似文献
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M. Odin A. Feurtet-Mazel F. Ribeyre A. Boudou 《Water, air, and soil pollution》1995,80(1-4):1003-1006
Accumulation of HgCl2 and CH3HgCl byHexagenia rigida nymphs from contaminated sediment and water column was investigated experimentally, taking into account 3 abiotic factors (temperature, pH and photoperiod). When the contamination of the experimental units was based on sediment compartment, Hg concentrations at the whole organism level revealed very high bioaccumulation differences between the two chemical forms of Hg (ratio close to 20 in favour of MeHg). When Hg compounds were added to the water column, the highest Hg accumulation rates were observed for MeHg, but with a small difference between the 2 compounds (ratio close to 2.0–3.0). These bioaccumulation processes were very dependent on the 3 abiotic factors taken into account, especially temperature and water column pH. 相似文献
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Ferrari Samuel Seródio Mettifogo Odin Luís Oliveira Cunha Matheus Fernando dos Santos Cordeiro Luis do Valle Polycarpo Gustavo Tropaldi Leandro 《Gesunde Pflanzen》2021,73(3):297-306
The use of herbicides and growth regulators in agricultural crops to reduce vegetative growth is widely studied worldwide. This study aimed to evaluate the agronomic traits of upland rice subjected to low doses of glufosinate-ammonium applied at different development stages. The treatments consisted of five low doses (0; 15; 30; 60; and 100?g a.i. ha?1; a.i.: active ingredient) of glufosinate-ammonium herbicide: a single low dose between active tillering (AT) and floral differentiation (FD); a single low dose after FD; low dose divided into two applications, the first at the beginning of the AT and the second between AT and FD; low dose divided into three applications, the first at the beginning of the AT, the second between AT and FD and the third after the FD, with four replications. The agronomic traits of upland rice were negatively affected due to the application of low doses of glufosinate-ammonium, with reduction in grain yield, 1000-grain weight, number of panicles, full spikelets and spikelets per panicle. Glufosinate-ammonium has no potential to be used as hormesis effect in rice plants due to loss in grain yield.
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The mineral series glaucony supplies 40% of the absolute-age database for the geologic time scale of the last 250 million years. However, glauconies have long been suspected of giving young potassium-argon ages on bulk samples. Laser-probe argon-argon dating shows that glaucony populations comprise grains with a wide range of ages, suggesting a period of genesis several times longer ( approximately 5 million years) than previously thought. An estimate of the age of their enclosing sediments (and therefore of time scale boundaries) is given by the oldest nonrelict grains in the glaucony populations, whereas the formation times of the younger grains appear to be modulated by global sea level. 相似文献
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Growth and feed conversion were monitored in triplicate groups of the African catfish Heterobranchus longifilis (mean weight 11 ± 1.8 g) fed small (2.5–5.54 cm) tilapia (Oreochromis niloticus) and artificial feeds at various rates (treatments 1, 2, and 3), and tilapia or artificial feed (treatments 4 and 5, respectively). Artificial feed was a 42% crude protein commercial pellet. Live O. niloticus were fed at a rate of 4 g live tilapia/catfish/day. Pelleted feeding rate was 2%, 1%, 0.5%, and 1% of body weight thrice daily in treatments 1, 2, 3, and 5, respectively. After 70 days, mean weight was 180 ± 9.5 g, 157 ± 15.7 g, 147 ± 2.6 g, 77 ± 10.9 g, and 74 ± 10 g, in treatments 1, 2, 3, 4, and 5, respectively. Treatment significantly affected SGR (% day?1) (P < 0.03) and pelleted feed conversion ratio (P < 0.0003). FCR was 1.09 ± 0.01, 0.63 ± 0.08, 0.42 ± 0.11, and 1.12 ± 0.13 in treatments 1, 2, 3, and 5, respectively. Profit was highest (P < 0.01) in treatment 2. Tilapia consumption seems to improve utilization of artificial feed and may be a way for some catfish farmers to save money. 相似文献
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Regulation of phagocytosis and [Ca2+]i flux by distinct regions of an Fc receptor. 总被引：13，自引：0，他引：13
J A Odin J C Edberg C J Painter R P Kimberly J C Unkeless 《Science (New York, N.Y.)》1991,254(5039):1785-1788
The binding of multivalent immunoglobulin G complexes to Fc receptors (Fc gamma Rs) on macrophages activates multiple immune functions. A murine macrophage cell line, but not a fibroblast cell line, that was transfected with human Fc gamma RIIA mediated phagocytosis and an intracellular Ca2+ concentration ([Ca2+]i) flux upon cross-linking of human Fc gamma RIIA. Transfected macrophages that expressed a truncated receptor lacking 17 carboxy-terminal amino acids phagocytosed small antibody complexes. However, only wild-type transfectants phagocytosed labeled erythrocytes and fluxed [Ca2+]i. Thus, the cytoplasmic domain of human Fc gamma RIIA contains distinct functional regions. 相似文献
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