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A. Wolf R. Aeckersberg H. W. Scherer A. Moeller W. Amelung 《Soil Use and Management》2012,28(2):177-184
The slow alteration of the surface of charred biomass (biochar) over time may contribute to an improved nutrient retention and thus fertility of tropical soils. Here, we investigated soils from temperate climates and investigated whether a technical steam activation of biochar could accelerate its positive effects on nutrient retention and uptake by plants relative to nonactivated biochar. To this aim, we performed microcosm experiments with sandy or silty soil, mixed with 2.0, 7.5 and 15.0 g/kg soil of fine (<2 mm) or coarse‐sized (2–10 mm) biochar from beech wood (Fagus sp.). After initial fertilizer (NPK), ashes and excess nutrients were leached with water, and the microcosms were planted for 142 days with Italian Ryegrass (Lolium multiflorum ssp. italicum). Thereafter, leachate, soil and plant samples were analysed for their nutrient contents. The results showed that biochar additions of ≤15 g/kg soil left elevated contents of available P and N in the surface soil but reduced their uptake into the plants. As a result, total biomass production was unchanged. Different particle size and application amounts influenced these findings only marginally. Nitrate leaching was enhanced in the sandy soil (+41% for nitrate, but reduced in the silty soil ?17%) and P was immobilized. Hence, the fertility of the temperate soils under study was only marginally affected by pure biochar amendments. Steam activation, however, almost doubled the positive effects of biochars in all instances, thus being an interesting option for future biochar applications. 相似文献
3.
SW PAGE 《Australian veterinary journal》1991,68(1):5-8
The use of chloramphenicol in the horse is now prohibited as horses are classified as food-producing animals. However, chloramphenicol has until recently been widely available for oral, intramuscular or intravenous administration. A critical appraisal of the published literature on the use of chloramphenicol in the horse clearly demonstrates that there are sound pharmacokinetic and microbiological reasons for concluding that chloramphenicol is not an appropriate antibiotic for systemic use. The short half-life of chloramphenicol in the horse, together with the broad range of minimum inhibitory concentrations of target pathogens, preclude the use of practical dosage regimens. It can be concluded that the withdrawal of chloramphenicol will have no adverse effects on chemotherapy in the horse. 相似文献
4.
R. Scherer P. Urfer M.R. Mayol L.D. Belingheri F. Marx M.J.J. Janssens 《Euphytica》2002,126(2):203-210
In order to start a genetic improvement program for quality in the Mate crop (Ilex paraguariensis), it was attempted to estimate the actual genetic parameters of caffeine, theobromine and related quality traits, using available
progeny tests in Misiones, Argentina. Using cluster analysis, eight groups of similar characteristics could be identified,
and individual within full-sib family selection for quality was performed. Additive effects were strong for caffeine but weak
for theobromine. Co-heritability between caffeine and theobromine was positive, suggesting that additive genetic correlations
and dominance correlations are concurring. The strong influence of paternal progenitors regarding caffeine needs more research.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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The uptake of N by ryegrass grown in pot culture on a range of soils differing widely in content of nonexchangeable NH4-N (topsoils: 117 to 354 mg kg?1 soil; subsoils: 117 to 270 mg kg?1 soil) was measured to indicate whether the amounts of NH4-N released from clay minerals were correlated with soil NH4-N. After two cuts soil analysis revealed that the amounts of mobilized nonexchangeable NH4-N were between 3.5 and 25.2 mg kg?1 from topsoils and between 0 and 8.2 mg kg?1 from subsoils. There was no correlation between soil nonexchangeable NH4-N content and release. The NH4-N extracted with 1 N HCl and the actual N uptake of the plants correlated highly significant. Assuming that the whole of the NH4-N released was taken up by ryegrass, NH4-N accounted for 11.2 to 75.0% of total N uptake from topsoils and 0 to 37.3% from subsoils. The release of nonexchangeable NH4-N was increased by the application of nitrate. 相似文献
7.
Soft lithography is an alternative to silicon-based micromachining that uses replica molding of nontraditional elastomeric materials to fabricate stamps and microfluidic channels. We describe here an extension to the soft lithography paradigm, multilayer soft lithography, with which devices consisting of multiple layers may be fabricated from soft materials. We used this technique to build active microfluidic systems containing on-off valves, switching valves, and pumps entirely out of elastomer. The softness of these materials allows the device areas to be reduced by more than two orders of magnitude compared with silicon-based devices. The other advantages of soft lithography, such as rapid prototyping, ease of fabrication, and biocompatibility, are retained. 相似文献
8.
The molecular basis of the sparse fur mouse mutation 总被引:30,自引:0,他引:30
The ornithine transcarbamylase-deficient sparse fur mouse is an excellent model to study the most common human urea cycle disorder. The mutation has been well characterized by both biochemical and enzymological methods, but its exact nature has not been revealed. A single base substitution in the complementary DNA for ornithine transcarbamylase from the sparse fur mouse has been identified by means of a combination of two recently described techniques for rapid mutational analysis. This strategy is simpler than conventional complementary DNA library construction, screening, and sequencing, which has often been used to find a new mutation. The ornithine transcarbamylase gene in the sparse fur mouse contains a C to A transversion that alters a histidine residue to an asparagine residue at amino acid 117. 相似文献
9.
Scherer SW Cheung J MacDonald JR Osborne LR Nakabayashi K Herbrick JA Carson AR Parker-Katiraee L Skaug J Khaja R Zhang J Hudek AK Li M Haddad M Duggan GE Fernandez BA Kanematsu E Gentles S Christopoulos CC Choufani S Kwasnicka D Zheng XH Lai Z Nusskern D Zhang Q Gu Z Lu F Zeesman S Nowaczyk MJ Teshima I Chitayat D Shuman C Weksberg R Zackai EH Grebe TA Cox SR Kirkpatrick SJ Rahman N Friedman JM Heng HH Pelicci PG Lo-Coco F Belloni E Shaffer LG Pober B Morton CC Gusella JF Bruns GA Korf BR 《Science (New York, N.Y.)》2003,300(5620):767-772
10.
Feng L Ayache M Huang J Xu YL Lu MH Chen YF Fainman Y Scherer A 《Science (New York, N.Y.)》2011,333(6043):729-733
Optical communications and computing require on-chip nonreciprocal light propagation to isolate and stabilize different chip-scale optical components. We have designed and fabricated a metallic-silicon waveguide system in which the optical potential is modulated along the length of the waveguide such that nonreciprocal light propagation is obtained on a silicon photonic chip. Nonreciprocal light transport and one-way photonic mode conversion are demonstrated at the wavelength of 1.55 micrometers in both simulations and experiments. Our system is compatible with conventional complementary metal-oxide-semiconductor processing, providing a way to chip-scale optical isolators for optical communications and computing. 相似文献