The geologically recent giant impact basins at Vesta's south pole     

Schenk P  O'Brien DP  Marchi S  Gaskell R  Preusker F  Roatsch T  Jaumann R  Buczkowski D  McCord T  McSween HY  Williams D  Yingst A  Raymond C  Russell C 《Science (New York, N.Y.)》2012,336(6082):694-697

Dawn's global mapping of Vesta reveals that its observed south polar depression is composed of two overlapping giant impact features. These large basins provide exceptional windows into impact processes at planetary scales. The youngest, Rheasilvia, is 500 kilometers wide and 19 kilometers deep and finds its nearest morphologic analog among large basins on low-gravity icy satellites. Extensive ejecta deposits occur, but impact melt volume is low, exposing an unusual spiral fracture pattern that is likely related to faulting during uplift and convergence of the basin floor. Rheasilvia obliterated half of another 400-kilometer-wide impact basin, Veneneia. Both basins are unexpectedly young, roughly 1 to 2 billion years, and their formation substantially reset Vestan geology and excavated sufficient volumes of older compositionally heterogeneous crustal material to have created the Vestoids and howardite-eucrite-diogenite meteorites.  相似文献   

The Importance of Therapeutic Farriery in Equine Practice     

Harry W. Werner 《Veterinary Clinics of North America: Equine Practice》2012

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Application of RVA and Time‐Lapse Photography to Explore Effects of Extent of Chlorination,Milling Extraction Rate,and Particle‐Size Reduction of Flour on Cake‐Baking Functionality     

Meera Kweon  Louise Slade  Harry Levine  Edward Souza 《Cereal Chemistry》2010,87(5):409-414

Three factors (extent of chlorination, milling extraction rate, and particle‐size reduction) in cake‐baking functionality of Croplan 594W flour were explored using a Rapid Visco‐Analyser (RVA) and time‐lapse photography. The extent of chlorination and milling extraction rate showed dramatic effects, but postmilling to reduce flour particle size was a less significant factor. RVA results showed that starch pasting was accelerated, and both peak and set‐back viscosities were enhanced, with increasing extent of chlorination. These effects were exaggerated by the high sugar concentration relevant to cake baking, compared to the same effects in water. Cake baking with chlorinated flours, in a formulation with 50% sugar (%S) and 275 parts total solvent (TS), showed that, as the extent of chlorination increased, cake moisture content and edge height decreased. Cake center height and shape factor were curvilinear, with maxima near flour with pH 4.6. Dramatic collapse occurred for cakes baked with unchlorinated flour samples, due to delayed starch pasting, as documented by time‐lapse photography and comparison to the geometry of the final cooled cakes. Starch pasting and egg white setting occurred too early for the cakes baked with excessively chlorinated flour (pH ≤4.0), but too late for the cakes baked with unchlorinated or insufficiently chlorinated flours (pH ≥4.9), compared to the ideal starch pasting and egg white setting behavior with appropriately chlorinated flours (pH >4.0 and <4.9). Informal sensory texture evaluation showed that cake mouthfeel was related to both moisture content per se and the relationship between moisture content and cake relative humidity (%RH). Excessive flour chlorination resulted in unacceptably dry cake mouthfeel.  相似文献   

Influence of cambial age and climate on ring width and wood density in Pinus radiata families     

Miloš Ivković  Washington Gapare  Harry Wu  Sergio Espinoza  Philippe Rozenberg 《Annals of Forest Science》2013,70(5):525-534

? Context

The correlation between tree ring width and density and short-term climate fluctuations may be a useful tool for predicting response of wood formation process to long-term climate change.

? Aims

This study examined these correlations for different radiata pine genotypes and aimed at detecting potential genotype by climate interactions.

? Methods

Four data sets comprising ring width and density of half- and full-sib radiata pine families were used. Correlations with climate variables were examined, after the extraction of the effect of cambial age.

? Results

Cambial age explained the highest proportion of the ring to ring variation in all variables. Calendar year and year by family interaction explained a smaller but significant proportion of the variation. Rainfall had a positive correlation with ring width and, depending on test site, either a negative or positive correlation with ring density. Correlations between temperature during growing season and ring density were generally negative.

? Conclusion

Climate variables that influence ring width and wood density can be identified from ring profiles, after removing the cambial age effect. Families can be selected that consistently show desirable response to climate features expected to become prevalent as a result of climate change.  相似文献   

Identification of strong aggregating regions in soy glycinin upon enzymatic hydrolysis     

Kuipers BJ  Gruppen H 《Journal of agricultural and food chemistry》2008,56(10):3818-3827

Upon hydrolysis with chymotrypsin, soy glycinin has a strong tendency to aggregate. The regions of glycinin from which the aggregating peptides originate were identified by accumulative-quantitative peptide mapping. To this end, the aggregating peptides were further hydrolyzed with trypsin to obtain peptides of which the sequence can be identified using RP-HPLC-MS/MS. This resulted in a hydrolysate in which 90% of the proteinaceous material was dissolved. The soluble fraction was analyzed using the method of accumulative-quantitative peptide mapping: fractionation using ion exchange chromatography, followed by identification of peptides by RP-HPLC-MS/MS, quantification based on the absorbance at 214 nm, and finally peptide mapping. For the peptide mapping the proportions in which each of the five glycinin subunits are present, as determined by Edman degradation, were taken into account. The results showed that mainly the basic polypeptide and a part of the acidic polypeptide, close to the location of the disulfide bridge between the basic and acidic polypeptides, are present in the aggregating peptide fraction. On the basis of the results obtained, an aggregation mechanism was proposed. The hydrophilic acidic polypeptides shield the hydrophobic basic polypeptides, and the former are preferentially degraded upon hydrolysis. This results in a net increase in hydrophobicity of the remaining material, which mainly consists of the basic polypeptide fragments. This increase in hydrophobicity is proposed to be the driving force in the aggregation of chymotrypsin-derived peptides of glycinin.  相似文献   

PI3K/AKT, JNK, and ERK pathways are not crucial for the induction of cholesterol biosynthesis gene transcription in intestinal epithelial cells following treatment with the potato glycoalkaloid alpha-chaconine     

Mandimika T  Baykus H  Poortman J  Garza C  Kuiper H  Peijnenburg A 《Journal of agricultural and food chemistry》2008,56(18):8745-8752

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Pesticide contamination of the upper Elbe River and an adjacent floodplain area     

Karlsson  Anneli S.  Lesch  Michael  Weihermüller  Lutz  Thiele  Björn  Disko  Ulrich  Hofmann  Diana  Vereecken  Harry  Spielvogel  Sandra 《Journal of Soils and Sediments》2020,20(4):2067-2081

Journal of Soils and Sediments - Pesticide contamination of river waters is a global problem, and therefore, authorities regularly monitor the water quality status. Especially, flood events might...  相似文献   

Phage display selection and characterization of single-chain recombinant antibodies against Eimeria tenella sporozoites     

Abi-Ghanem D  Waghela SD  Caldwell DJ  Danforth HD  Berghman LR 《Veterinary immunology and immunopathology》2008,121(1-2):58-67

A single-chain antibody library against Eimeria tenella sporozoites was constructed by phage display. Antibody-displaying phage was selected in five panning rounds against cryopreserved E. tenella sporozoites. A 1000-fold increase in phage output and a 3000-fold enrichment were obtained after three rounds of panning, as the binding clones became the dominant population in the library. Ten clones were randomly selected from the last selection round, and their nucleotide sequences were aligned and compared to chicken germ-line sequences. Analysis of the light chain variable regions revealed possible donor pseudogenes which act as donors in gene conversion events, and contribute to the diversification of the V(L) immune repertoire. Possible somatic hypermutation events, a consequence of affinity maturation, were also identified. Soluble antibody was produced in a non-suppressor E. coli strain, purified by nickel affinity chromatography, and characterized by immunoblotting. In an immunofluorescence assay, this recombinant antibody showed specific binding to E. tenella sporozoites.  相似文献   

Isolation of Escherichia fergusonii from the feces and internal organs of a goat with diarrhea          下载免费PDF全文

Hariharan H  López A  Conboy G  Coles M  Muirhead T 《The Canadian veterinary journal. La revue veterinaire canadienne》2007,48(6):630-631

A fecal sample from a 42-year-old goat with a 2-month history of poor weight gain and diarrhea yielded a moderate growth of an organism resembling Salmonella spp. on MacConkey agar. The organism was identified as Escherichia fergusonii. The animal was euthanized. Samples of intestine, lung, liver, and kidney yielded the same organism, E. fergusonii.  相似文献   

Kinetic modeling of the thermal aggregation of patatin.     

A M Pots  H Gruppen  H H de Jongh  M A van Boekel  P Walstra  A G Voragen 《Journal of agricultural and food chemistry》1999,47(11):4593-4599

A kinetic model of the thermal aggregation of patatin is presented based on chromatographic analysis of the proportions of nonaggregated and aggregated patatin. It was observed that the decrease of the amount of nonaggregated patatin proceeded initially quickly and was followed by slower aggregation at longer incubation times. It was shown that this behavior was not due to heterogeneity of the starting material. It was noted that overestimation of the amount of native molecules after a heat treatment, caused by refolding of the unfolded protein during the cooling step prior to the analysis, was significant and could not be neglected. Hence, corrections based on information on the structural properties of patatin were applied. Taking this into account, a model was proposed consisting of a first-order formation of reactive particles, followed by a second-order aggregation reaction. This model described the thermal aggregation of patatin rather accurately and was confirmed by experiments at various protein concentrations.  相似文献