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Effects of coralline lime on yield and nutrient uptake by sweet corn (Zea mays saccharata Sturt.) and peanut (Arachis hypogea) were studied at three locations in Western Samoa. Coarse (0-10 mm) coralline material containing 31.1% Ca and 1.67% Mg was used as lime. There were two modes of application: band and broadcast, and three rates: 6, 12 and 18 ton ha–1. In the highest rainfall location, marketable yields were increased by 250% for peanut and 160% for sweet corn by liming at 6 ton ha–1, relative to the unamended control. Peanut yield increases were associated with reduced Mn toxicity and/or with Ca and Mg deficiency. Sweet corn was less susceptible to Mn toxicity, but more responsive to exchangeable Ca. The critical level of exchangeable Ca was found to be about 2.0 cmol(+)kg–1. Applying lime to a band of 0.25-m wide did not reduce yield relative to broadcast. Soil cultivation caused the lime to spread over a wider band, diluting the applied calcium with a larger soil volume, suggesting that less than 6 ton ha–1 broadcast coarse coralline lime could still be adequate for most Samoan soils.  相似文献   
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Conformational changes in the prion protein (PrP) seem to be responsible for prion diseases. We have used conformation-dependent chemical-shift measurements and rotational-resonance distance measurements to analyze the conformation of solid-state peptides lacking long-range order, corresponding to a region of PrP designated H1. This region is predicted to undergo a transformation of secondary structure in generating the infectious form of the protein. Solid-state NMR spectra of specifically 13C-enriched samples of H1, residues 109-122 (MKHMAGAAAAGAVV) of Syrian hamster PrP, have been acquired under cross-polarization and magic-angle spinning conditions. Samples lyophilized from 50% acetonitrile/50% water show chemical shifts characteristic of a beta-sheet conformation in the region corresponding to residues 112-121, whereas samples lyophilized from hexafluoroisopropanol display shifts indicative of alpha-helical secondary structure in the region corresponding to residues 113-117. Complete conversion to the helical conformation was not observed and conversion from alpha-helix back to beta-sheet, as inferred from the solid-state NMR spectra, occurred when samples were exposed to water. Rotational-resonance experiments were performed on seven doubly 13C-labeled H1 samples dried from water. Measured distances suggest that the peptide is in an extended, possibly beta-strand, conformation. These results are consistent with the experimental observation that PrP can exist in different conformational states and with structural predictions based on biological data and theoretical modeling that suggest that H1 may play a key role in the conformational transition involved in the development of prion diseases.  相似文献   
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Explored several psychological factors assumed, on the basis of clinical observation, to be related to undesired pregnancy because of failure to take contraceptive precautions. Differences in risk taking, use of denial as a defense, masochism, and sex guilt were explored among 3 groups of White college women: 33 who had voluntarily sought an abortion, 25 using medically prescribed contraceptive methods, and 26 unselected with regard to their sexual activity or contraceptive practices. Measures used included the Choice Dilemmas Questionnaire, Defense Mechanisms Inventory, and Mosher Forced-Choice Guilt Inventory. Significantly higher scores on scales reflecting use of denial and masochism were found in the abortion group, but no support was found for greater risk taking or sex guilt. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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This paper deals with the problem of limited natural and non-renewable resources and their impact on the construction sector. A demonstration is given of how quantitative influences can be determined by means of an appropriate life-cycle approach. An input/output flow diagram and a simple formula are presented and discussed in order to obtain more knowledge of the problem being investigated. Besides the theoretical work, the paper also covers some of the practical implications and methods of reducing the consumption of limited resources and environmental losses in the field of construction.  相似文献   
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This paper focuses on the use of modified nano-clay particles as a controlled release system for biocides from building materials. Different (model) biocides were incorporated in a biocide/nano-clay composite and subsequently the release of the biocides was monitored under different environmental conditions. In addition, the biocide/clay material was formulated into a model finishing material (gypsum) to evaluate the antifungal activity. Intercalation of biocides in modified nano-clays was found to significantly prolong the release of the biocide and prevent premature leaching of the biocide from the building material. Release rate of the biocide could be tuned by selection of the type of modification used for the nano-clay platelets. Even after prolonged leaching up to 45 days in artificial rain tests, gypsum samples containing biocide/clay composites did not show any fungal growth, whereas gypsum samples containing pure biocide had lost their antifungal activity after exposure to artificial rain for 7 days or more, demonstrating the potential of this technology for practical applications. The presented approach is very versatile, and may be used for a large variety of biocides and is envisioned to be applicable to different construction and finishing materials, including waterborne paints. To optimize the performance in a specific application area, the leaching or release process of the nano-clays should be known in the different application materials, and consequently requires alternative testing methods, e.g. methods which characterize the fungal growth as a function of release in more detail. Although correlation with practice requires further investigation, the presented method gives a good first indication for prolonged protection of building materials.  相似文献   
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A variation on the unreacted shrinking core model has been developed for calcination and similar non-catalytic solid-to-gas decomposition reactions in which no gaseous reactant is involved and the reaction rate decreases with increasing product gas concentration. The numerical solution of the model has been validated against an analytical solution for the isothermal case. The model parameters have been tuned using literature data for the thermal dehydration (calcination) of gibbsite to alumina over a wide range of temperatures, from 490 to 923 K. The model results for gibbsite conversion agreed well with the published experimental data. A reaction order with respect to water vapor concentration of n = ?1 was found to give a good fit to the data and yield activation energies consistent with literature values. Predictions of the non-isothermal unreacted shrinking core model compare well with a more complex distributed model developed previously by the authors.  相似文献   
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An open-label, multicenter study was conducted to determine the efficacy and safety of oral risedronate (a pyridinyl bisphosphonate) in 162 patients (102 men, 60 postmenopausal women; mean age, 68 years) with moderate to severe Paget's disease of bone (mean serum alkaline phosphatase [ALP] approximately seven times the upper limit of normal). Patients were treated with oral risedronate, 30 mg/day for 84 days, followed by 112 days without treatment. This 196-day cycle was repeated once if serum ALP did not normalize or increased from the nadir value by > or = 25%. At the end of the first and second cycles, the mean percentage decreases for serum ALP were 65.7% and 69.1%, and for urinary hydroxyproline/creatinine 50.4% and 66.9%, respectively. The decreases from baseline in ALP and urinary hydroxyproline/creatinine were significant (p < 0.001). Normalization of serum ALP was observed in 86 patients (53.8%): 53 during the first treatment cycle and 33 during the second. There was a significant proportion of patients reporting a decrease in the pagetic bone pain at days 84 and 196 (p < 0.001). Overall, risedronate was well tolerated. Five patients withdrew due to adverse events, none of which were considered to be drug related. In conclusion, 30 mg of oral risedronate administered daily for 84 days significantly reduced the biochemical indices of disease activity and was associated with pain reduction in patients with moderate to severe Paget's disease of bone. Normalization of ALP was observed in the majority of patients. Repeated administration of risedronate was shown to be beneficial. In general, risedronate was well tolerated and demonstrated a good safety profile.  相似文献   
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