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141.
Landscape Ecology - Current diversity and species composition of ecological communities can often not exclusively be explained by present land use and landscape structure. Historical land use may...  相似文献   
142.
143.
Lipopolysaccharide (LPS) was obtained from Pasteurella haemolytica serotype 1, using phenol-water extraction, and was evaluated for its ability to modify the biological activity of bovine leukocytes. The LPS was not toxic to polymorphonuclear leukocytes (PMN). The LPS preparation had little effect on random migration of PMN or mononuclear leukocytes (MNL), but caused a 2.5- to 3- fold increase in migration of cells within a whole peripheral blood leukocyte preparation. Phagocytosis of [125I]-labeled Staphylococcus aureus by PMN decreased with low (2.5 micrograms/10(6) cells) and high (65 micrograms/10(6) cells) concentrations of LPS and increased with moderate concentrations of LPS (5 to 25 micrograms/10(6) cells). The LPS enhanced nitroblue tetrazolium reduction by PMN. Moderate LPS concentrations (25 to 50 micrograms/10(6) cells) were mitogenic for MNL, whereas high LPS concentrations (300 micrograms/10(6) inhibited [3H]thymidine incorporation by MNL.  相似文献   
144.
Soybeans were germinated on a kilogram-scale, by the application of malting technology used in the brewing industry, and concomitantly challenged with Rhizopus microsporus var. oryzae. In a time-course experiment, samples were taken every 24 h for 10 days, and the isoflavonoid profile was analyzed by RP-UHPLC-MS. Upon induction with R. microsporus, the isoflavonoid composition changed drastically with the formation of phytoalexins belonging to the subclasses of the pterocarpans and coumestans and by prenylation of the various isoflavonoids. The pterocarpan content stabilized at 2.24 mg of daidzein equivalents (DE) per g after ~9 days. The levels of the less common glyceofuran, glyceollin IV, and V/VI ranged from 0.18 to 0.35 mg DE/g and were comparable to those of the more commonly reported glyceollins I, II, and III (0.22-0.32 mg DE/g) and glycinol (0.42 mg DE/g). The content of prenylated isoflavones after the induction process was 0.30 mg DE/g. The total isoflavonoid content increased by a factor of 10-12 on DW basis after 9 days, which was suggested to be ascribable to de novo synthesis. These changes were accompanied by a gradual increase in agonistic activity of the extracts toward both the estrogen receptor α (ERα) and ERβ during the 10-day induction, with a more pronounced activity toward ERβ. Thus, the induction process yielded a completely different spectrum of isoflavonoids, with a much higher bioactivity toward the estrogen receptors. This, together with the over 10-fold increase in potential bioactives, offers promising perspectives for producing more, novel, and higher potency nutraceuticals by malting under stressed conditions.  相似文献   
145.
Objective To determine the severity and distribution of structural changes in the brains of adult sheep stunned by penetrating captive bolt.
Procedure The unconstrained heads of ten, anaesthetised, unhorned, 2-year-old Merino sheep were impacted at the summit of the head with a penetrating captive bolt pistol. Six sheep were ventilated and four received no respiratory support. Two hours after impact, brains from the six ventilated sheep were perfusion-fixed with 4% paraformaldehyde. Sixteen whole, serial coronal sections from each brain were stained with haematoxylin and eosin and immunohistochemi-cally for amyloid precursor protein, a sensitive marker of axonal and neuronal reaction in the brain after trauma. Pathological changes in these brains were then quantified by morphometric analysis.
Results Structural change in all impacted brains was a mixture of focal injury around the wound track and more widely distributed damage in the cerebral hemispheres, cerebellum and brainstem, but varied considerably in severity between individual sheep. All nonventilated sheep died rapidly following respiratory arrest.
Conclusions After penetrating captive bolt stunning, damage to the central reticular formation, axonal connections, and the cortical mantle is the likely reason for failure of respiratory control and traumatic loss of consciousness.  相似文献   
146.
Osmium isotopic analyses of picritic lavas from Hawaii show enrichments in the osmium-186/osmium-188 ratio (186Os/188Os) of 0. 008 to 0.018%, relative to a chondritic upper mantle, that are positively correlated with enrichments in 187Os/188Os of 5.4 to 9.0%. The most viable mechanism to produce these coupled 186Os and 187Os enrichments is by addition of 0.5 to 1 weight percent of outer core metal to a portion of the D" layer and subsequent upwelling of the mixture. These data suggest that some plumes originate at the core-mantle boundary and that Os isotopes may be used to distinguish plumes derived from shallow versus deep mantle sources.  相似文献   
147.
Pinto beans were milled and then air-classified to obtain a raw high protein fraction (RHPF) followed by extrusion to texturize the protein fraction. The texturized high protein fraction (THPF) was then milled to obtain flour, and combined with wheat flour at 5, 10, and 15 % levels to make bread. The air-classification process produced flour with high concentration of lipids and phytic acid in the protein-rich fraction. However, extrusion significantly reduced hexane extractable lipid and phytic acid. However, the reduction observed may simply indicate a reduction in recovery due to bind with other components. Total protein and lysine contents in composite flours increased significantly as THPF levels increased in composite flour. Bread made with 5 % THPF had 48 % more lysine than the 100 % wheat flour (control). The THPF helped to maintain dough strength by reducing mixing tolerance index (MTI), maintaining dough stability and increasing departure time on Farinograph. Bread loaf volume was significantly reduced above 5 % THPF addition. THPF increased water absorption causing an increase in bread weights by up to 6 %. Overall, loaf quality deteriorated at 10 and 15 % THPF levels while bread with 5 % THPF was not significantly different from the control. These results support the addition of 5 % THPF as a means to enhance lysine content of white pan bread.  相似文献   
148.
Splitting of the sun's global oscillation frequencies by large-scale flows can be used to investigate how rotation varies with radius and latitude within the solar interior. The nearly uninterrupted observations by the Global Oscillation Network Group (GONG) yield oscillation power spectra with high duty cycles and high signal-to-noise ratios. Frequency splittings derived from GONG observations confirm that the variation of rotation rate with latitude seen at the surface carries through much of the convection zone, at the base of which is an adjustment layer leading to latitudinally independent rotation at greater depths. A distinctive shear layer just below the surface is discernible at low to mid-latitudes.  相似文献   
149.
Helioseismology is probing the interior structure and dynamics of the sun with ever-increasing precision, providing a well-calibrated laboratory in which physical processes can be studied under conditions that are unattainable on Earth. Nearly 10 million resonant modes of oscillation are observable in the solar atmosphere, and their frequencies need to be known with great accuracy in order to gauge the sun's interior. The advent of nearly continuous imaged observations from the complementary ground-based Global Oscillation Network Group (GONG) observatories and the space-based Solar and Heliospheric Observatory instruments augurs a new era of discovery. The flow of early results from GONG resolves some issues and raises a number of theoretical questions whose answers are required for understanding how a seemingly ordinary star actually operates.  相似文献   
150.
New specimens of middle Eocene Basilosaurus isis from Egypt include the first functional pelvic limb and foot bones known in Cetacea. These are important in corroborating the intermediate evolutionary position of archaeocetes between generalized Paleocene land mammals that used hind limbs in locomotion and Oligocene-to- Recent whales that lack functional pelvic limbs. The foot is paraxonic, consistent with derivation from mesonychid Condylarthra. Hind limbs of Basilosaurus are interpreted as copulatory guides.  相似文献   
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