Estimating biomass     

Botkin DB  Simpson LG  Schenk HJ 《Science (New York, N.Y.)》1992,257(5067):146

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Characteristics of phosphorus uptake kinetics of poinsettia and marigold     

Azizollah Khandan-Mirkohi  Manfred K. Schenk 《Scientia Horticulturae》2009

In a previous experiment it has been found that maximum uptake rate (I_max), Michaelis constant (K_m), and minimum nutrient concentration (C_min) as plant physiological characteristics may be important for phosphorus (P) uptake in peat-substrate. Thus, variation of P uptake parameters was evaluated with a series of depletion studies for poinsettia (Euphorbia pulcherrima) and marigold (Tagetes patula) under fluctuating climatic conditions and different developmental stages.  相似文献   

Primary intestinal lymphangiectasia in three dogs: a morphological and immunopathological investigation     

M M Suter  D G Palmer  H Schenk 《Veterinary pathology》1985,22(2):123-130

Morphological and immunological findings of three dogs with primary lymphangiectasia are described and compared with three normal dogs. Scanning electron microscopy showed distended and fused intestinal villi in dogs with intestinal lymphangiectasia, and morphometric evaluation revealed deeper crypts in the small intestine of dogs with intestinal lymphangiectasia. Although plasma cells of all classes were diminished in the cranial parts of the small intestine, there was an absolute and relative increase of immunoglobulin G-containing plasma cells in the caudal small intestine in dogs with intestinal lymphangiectasia.  相似文献   

Accurate Dereplication of Bioactive Secondary Metabolites from Marine-Derived Fungi by UHPLC-DAD-QTOFMS and a MS/HRMS Library     

Sara Kildgaard  Maria Mansson  Ina Dosen  Andreas Klitgaard  Jens C. Frisvad  Thomas O. Larsen  Kristian F. Nielsen 《Marine drugs》2014,12(6):3681-3705

In drug discovery, reliable and fast dereplication of known compounds is essential for identification of novel bioactive compounds. Here, we show an integrated approach using ultra-high performance liquid chromatography-diode array detection-quadrupole time of flight mass spectrometry (UHPLC-DAD-QTOFMS) providing both accurate mass full-scan mass spectrometry (MS) and tandem high resolution MS (MS/HRMS) data. The methodology was demonstrated on compounds from bioactive marine-derived strains of Aspergillus, Penicillium, and Emericellopsis, including small polyketides, non-ribosomal peptides, terpenes, and meroterpenoids. The MS/HRMS data were then searched against an in-house MS/HRMS library of ~1300 compounds for unambiguous identification. The full scan MS data was used for dereplication of compounds not in the MS/HRMS library, combined with ultraviolet/visual (UV/Vis) and MS/HRMS data for faster exclusion of database search results. This led to the identification of four novel isomers of the known anticancer compound, asperphenamate. Except for very low intensity peaks, no false negatives were found using the MS/HRMS approach, which proved to be robust against poor data quality caused by system overload or loss of lock-mass. Only for small polyketides, like patulin, were both retention time and UV/Vis spectra necessary for unambiguous identification. For the ophiobolin family with many structurally similar analogues partly co-eluting, the peaks could be assigned correctly by combining MS/HRMS data and m/z of the [M + Na]⁺ ions.  相似文献   

Cyanidadsorption an Sesquioxiden,Tonmineralen und Huminstoffen     

Birgit Schenk  B. M. Wilke 《植物养料与土壤学杂志》1984,147(6):669-679

Cyanide adsorption on sesquioxides, clay-minerals and humic substances The adsorption of cyanide (KCN) on sesquioxides, clay minerals, and humic substances at different pH-values was studied. Moreover we looked for the CN-adsorption on L-layers of the humus forms mull, moder and mor. Cyanide was only adsorbed by humic acid. The amount of CN adsorbed increased with increasing pH of the reaction solution. IR-spectroscopic investigations of CN treated humic acids revealed that the cyanide was adsorbed at low pH (<7) as HCN-molecules by formation of hydrogen bonds with COOH-, COH-, OH- and NH₂-groups of the humic acid. At pH > 7 the cyanide was mainly adsorbed as CN^? by charge transfer with acceptor-molecules such as chinones. The cyanide adsorption of L-layers of humus forms decreased in the order mor > mull > moder. It is surmised that the HCN-molecules were not only adsorbed by humic acids in these layers but also by oxidation products of lignin, pectin, protein, cellulose, and carbon-hydrates of fulvic acids. Solutions of K₂HPO₄ did not desorb cyanides from humic acids to any great extent.  相似文献   

New horizons mapping of Europa and Ganymede     

Grundy WM  Buratti BJ  Cheng AF  Emery JP  Lunsford A  McKinnon WB  Moore JM  Newman SF  Olkin CB  Reuter DC  Schenk PM  Spencer JR  Stern SA  Throop HB  Weaver HA;New Horizons Team 《Science (New York, N.Y.)》2007,318(5848):234-237

The New Horizons spacecraft observed Jupiter's icy satellites Europa and Ganymede during its flyby in February and March 2007 at visible and infrared wavelengths. Infrared spectral images map H2O ice absorption and hydrated contaminants, bolstering the case for an exogenous source of Europa's "non-ice" surface material and filling large gaps in compositional maps of Ganymede's Jupiter-facing hemisphere. Visual wavelength images of Europa extend knowledge of its global pattern of arcuate troughs and show that its surface scatters light more isotropically than other icy satellites.  相似文献   

Io volcanism seen by new horizons: a major eruption of the Tvashtar volcano     

Spencer JR  Stern SA  Cheng AF  Weaver HA  Reuter DC  Retherford K  Lunsford A  Moore JM  Abramov O  Lopes RM  Perry JE  Kamp L  Showalter M  Jessup KL  Marchis F  Schenk PM  Dumas C 《Science (New York, N.Y.)》2007,318(5848):240-243

Jupiter's moon Io is known to host active volcanoes. In February and March 2007, the New Horizons spacecraft obtained a global snapshot of Io's volcanism. A 350-kilometer-high volcanic plume was seen to emanate from the Tvashtar volcano (62 degrees N, 122 degrees W), and its motion was observed. The plume's morphology and dynamics support nonballistic models of large Io plumes and also suggest that most visible plume particles condensed within the plume rather than being ejected from the source. In images taken in Jupiter eclipse, nonthermal visible-wavelength emission was seen from individual volcanoes near Io's sub-Jupiter and anti-Jupiter points. Near-infrared emission from the brightest volcanoes indicates minimum magma temperatures in the 1150- to 1335-kelvin range, consistent with basaltic composition.  相似文献   

Apple mealiness detection using fluorescence and self-organising maps     

Dimitrios Moshou  Stijn Wahlen  Reto Strasser  Ann Schenk  Herman Ramon 《Computers and Electronics in Agriculture》2003,40(1-3):103

The chlorophyll fluorescence kinetics of ‘Jonagold’ and ‘Cox’ apples, stored under different conditions to induce mealiness, were measured. Three different storage conditions were considered causing three mealiness levels: not mealy, moderately and strongly mealy. Also destructive measurements of the texture (firmness, hardness, juice content and soluble solids content) were done. Classification into different mealiness levels based on the fluorescence measurements was more performant than a classification based on the destructive measurements. To estimate the mealiness level in a non-destructive way from the fluorescence features, a number of different classifiers were constructed. Quadratic discriminants and supervised and unsupervised neural networks were tested and compared. The self-organising map gives promising results when compared with the multi-layer perceptrons and quadratic discriminant analysis. The different advantages of the constructed classifiers suggest that fluorescence can be used in an automatic sorting line to assess certain types of mealiness.  相似文献   

Hardrot van Gladiolen,veroorzaakt doorSeptoria gladioli     

P. K. Schenk 《European journal of plant pathology / European Foundation for Plant Pathology》1960,66(3):205-227

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Finite mixture model analysis of microarray expression data on samples of uncertain biological type with application to reproductive efficiency     

Bing N  Hoeschele I  Ye K  Eilertsen KJ 《Veterinary immunology and immunopathology》2005,105(3-4):187-196

Common goals of microarray experiments are the detection of genes that are differentially expressed between several biological types and the construction of classifiers that predict biological type of samples. Here we consider a situation where there is no training data. There is considerable interest in comparing expression profiles associated with successful pregnancies (SP) and unsuccessful pregnancies (UP) in model and farm animals. Successful pregnancy rate is known to be much higher in embryos generated by in vitro fertilization (IVF) than in nuclear transfer (NT) embryos, and higher under induced ovulation for large follicles (LF) than for small follicles (SF). The tasks of identifying genes differentially expressed between SP and UP, and predicting SP for future samples are not well accomplished by comparing IVF and NT, or LF and SF. A suitable method is finite mixture model analysis (FMMA), which models each observed class (IVF and NT, or LF and SF) as a mixture of two distributions, one for SP and one for UP, with different known or unknown proportions (here known to be 0.50 SP for IVF and 0.02 SP for NT). The means of the two distributions differ for the differentially expressed genes, which we identify via a likelihood ratio test. We confirm by simulation that FMMA strongly outperforms hierarchical clustering and linear discriminant analysis using the known class labels (NT, IVF). We apply FMMA to a real data set on IVF and NT embryos, and compute their posterior probabilities of SP, which confirm our prior knowledge of the SP proportions for IVF and NT.  相似文献