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71.
Ernst RK Yi EC Guo L Lim KB Burns JL Hackett M Miller SI 《Science (New York, N.Y.)》1999,286(5444):1561-1565
Cystic fibrosis (CF) patients develop chronic airway infections with Pseudomonas aeruginosa (PA). Pseudomonas aeruginosa synthesized lipopolysaccharide (LPS) with a variety of penta- and hexa-acylated lipid A structures under different environmental conditions. CF patient PA synthesized LPS with specific lipid A structures indicating unique recognition of the CF airway environment. CF-specific lipid A forms containing palmitate and aminoarabinose were associated with resistance to cationic antimicrobial peptides and increased inflammatory responses, indicating that they are likely to be involved in airway disease. 相似文献
72.
Ernst Knippel Röhrl Schüpster Schaile und Fabricius 《Forstwissenschaftliches Centralblatt》1927,49(19):687-703
Ohne Zusammenfassung 相似文献
73.
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75.
Many forest ecosystems in Germany are strongly influenced by emissions of pollutants like SO2 and alkaline dusts. To quantify and evaluate the consequences of long‐term fly ash deposition on forest soils, a study was conducted in pine stands (Pinus sylvestris) in the Dübener Heide in Northeastern Germany. This forest area has been influenced mainly by emissions from coal‐fired power plants and the chemical industry of the industrial region Bitterfeld‐Wolfen‐Zschornewitz since the early 1900. The study sites are located along a fly ash deposition gradient of 8, 16, 14, 18, and 25 km away from the main emission source in Bitterfeld (sites 1, 2, 3, 4, and 5, respectively). Samples of the organic horizons (Oi, Oe, and Oa) and mineral topsoil (0—10 cm) were taken in fall 1998 and analyzed for their ferromagnetic susceptibility and total ash content. Scanning electron microscopy (SEM) and energy dispersive X‐ray microanalysis (EDX) were performed on selected samples to differentiate between the pedogenic and atmospheric origin of the mineral components in the organic horizons. As a result of the long‐term deposition, ferromagnetic fly ash components are mainly accumulated in the Oe and Oa horizons of the forest soils studied. Ferromagnetic susceptibility was significantly higher (p ≤ 0.05) in the Oe horizon of sites 1 and 2 compared to sites 3, 4, and 5. Unusually high total ash contents for organic horizons of > 74 % were determined in the Oa at all sites. SEM revealed 3 distinct features of persistent fly ash deposits from coal‐fired power plants within the organic horizons that can be defined as ”︁stable glasses” with magnetic properties, aluminum‐silicate‐minerals, and slag fragments. SEM and EDX indicated that a great portion of the mineral particles found in the organic horizons of forests soils influenced by fly ash are from atmospheric sources. For detection of atmospheric lignite‐derived deposition into forest soils, the Oe and Oa horizons have to be considered as specific diagnostic horizons because they show indicative properties for such soils. 相似文献
76.
Ferralsols have high structural stability, although structural degradation has been observed to result from forest to tillage or pasture conversion. An experimental series of forest skidder passes in an east Amazonian natural forest was performed for testing the effects of mechanical stress during selective logging operations on a clay‐rich Ferralsol under both dry and wet soil conditions. Distinct ruts formed up to 25 cm depth only under wet conditions. After nine passes the initially very low surface bulk density of between 0.69 and 0.80 g cm?3 increased to 1.05 g cm?3 in the wet soil and 0.92 g cm?3 in the dry soil. Saturated hydraulic conductivities, initially >250 mm h?1, declined to a minimum of around 10 mm h?1 in the wet soil after the first pass, and in the dry soil more gradually after nine passes. The contrasting response of bulk density and saturated hydraulic conductivity is explained by exposure of subsoil material at the base of the ruts where macrostructure rapidly deteriorated under wet conditions. We attribute the resultant moderately high hydraulic conductivities to the formation of stable microaggregates with fine sand to coarse silt textures. We conclude that the topsoil macrostructure of Ferralsols is subject to similar deterioration to that of Luvisols in temperate zones. The stable microstructure prevents marked compaction and decrease in hydraulic conductivity under wetter and more plastic soil conditions. However, typical tropical storms may regularly exceed the infiltration capacity of the deformed soils. In the deeper ruts water may concentrate and cause surface run‐off, even in gently sloping areas. To avoid soil erosion, logging operations in sloping areas should therefore be restricted to dry soil conditions when rut formation is minimal. 相似文献
77.
Hildebrand B Boguhn J Dänicke S Rodehutscord M 《Journal of animal physiology and animal nutrition》2012,96(2):307-318
In this study, the effect of Fusarium toxin-contaminated triticale (FUS) at high (60%) and low (30%) concentrate proportion in ruminant rations on ruminal fermentation, microbial protein synthesis and digestibility was investigated, using in vivo and in vitro methods. Significant effects of the forage-to-concentrate ratio on ruminal degradation and digestibility of crude nutrients and detergent fibre fractions as well as on the pH value and the concentration of short chain fatty acids (SCFA) in rumen fluid were found. The production of SCFA was affected, and the degradation of crude fibre and neutral detergent fibre in the rumen was reduced by the inclusion of FUS at high concentrate proportion. The efficiency of microbial crude protein synthesis was higher in diets with 60% than in diets with 30% concentrates, but was impaired in the presence of FUS in vitro at the high concentrate level. Marginal effects of FUS on the amino acid pattern of microbial protein were detected. It was concluded that the use of FUS in high concentrate diets can influence ruminal fermentation and microbial protein synthesis at a dietary deoxynivalenol concentration below 5 mg/kg dry matter. 相似文献
78.
79.
Watchareewan Jamboonsri Timothy D. Phillips Robert L. Geneve Joseph P. Cahill David F. Hildebrand 《Genetic Resources and Crop Evolution》2012,59(2):171-178
Chia, Salvia hispanica L., was well developed into a cultivated crop and an important component of Mesoamerican cultures and nutrition. Early Mesoamerican
breeders produced lines with well developed agronomic characteristics including good, uniform seed yield and retention. Seed
retention in particular is disadvantageous for survival in the wild. Maize, beans and squash were developed into important
crops concomitant with chia in Mesoamerica but unlike these other crops lack of photoperiodic variability in floral induction
limited the spread of chia cultivation into North America. There has been renewed interest in chia as an excellent source
of ω3 fatty acids and dietary fiber for healthy diets. Such highly unsaturated oils also are useful starting materials for
many renewable chemicals. Further we find chia grows very well in Midwestern and Eastern USA but flowers too late in the season
for seeds to mature before killing frosts. We set out to develop the genetic diversity in floral induction to provide germplasm
for production in the US and other temperate areas of the world. We demonstrate that new early flowering lines are able to
flower under a photoperiod of 15 h under greenhouse conditions. In field conditions, some selected new lines flowered at a
photoperiod of 14 h and 41 min during the 2009 growing season in Kentucky and can produce seeds in a range of environments
in temperate areas. 相似文献
80.
Pancuronium bromide was administered to calves to define the dosage level necessary to produce surgical relaxation (90% to 99% reduction of base-line evoked, hindlimb digital-extensor muscle twitch tension). Initial dosage level requirement was 43 +/- 9 micrograms/kg of body weight. Calves with this degree of relaxation required 26 +/- 14 minutes to achieve 50% recovery and 43 +/- 19 minutes to achieve complete return of base-line muscle twitch. Calves given a repeat injection of pancuronium at base-line muscle twitch required 27 +/- 9 micrograms/kg to achieve relaxation similar to that of the 1st dose. The 2nd dose did not last as long as the 1st, with complete recovery occurring in 37 +/- 12 minutes. Maximum evoked tension occurred at 200- to 400-g resting tension on the hoof. There was an absence of heart rate or blood pressure changes after injection of relaxant and a variable and inconsistent fade response to train-of-four and tetanic stimulus of the facial muscles. Acid-base values were alkalemic (pHa 7.5 +/- 0.08) when ventilation was controlled at eucapnia (PaCO2, 25 to 45 mm of Hg). 相似文献