Longitudinal trends in pH and aluminum chemistry of the Coxing Kill,Ulster County,New York     

Alexandra M. Shultz  Marianne H. Begemann  Denise A. Schmidt  Kathleen C. Weathers 《Water, air, and soil pollution》1993,69(1-2):113-125

The purpose of this work was to characterize the Al chemistry along the longitudinal pH gradient of the Coxing Kill and thereby provide a basis for an in depth study of aluminum chemistry and transport as a function of pH. Water samples were collected along the pH gradient and analyzed for monomeric Al species, strong acid anions, base cations, ammonium, dissolved organic C and dissolved silica. Inorganic monomeric Al, organic momonmeric Al and dissolved organic C decreased in concentration as the stream's drainage area and pH increased. The ratio of organic to inorganic monomeric Al and the concentration of all other species increased with increasing pH. An abrupt change in stream chemistry occurred in conjunction with the gradual changes expected for a low order stream draining an acid sensitive watershed impacted by acid deposition. This abrupt change partially resulted from geological characteristics of the watershed.  相似文献   

Factors affecting the collection and fitting of nuclear magnetic cross-relaxation spectroscopy data with application to waxy corn starch   总被引：2，自引：0，他引：2  

Lewen KS  McCormick IH  Molitor P  Schmidt SJ  Eads TM 《Journal of agricultural and food chemistry》2000,48(10):4469-4476

An examination of the methods for nuclear magnetic cross-relaxation spectroscopy (CRS) data collection and analysis was conducted using water and an aqueous waxy corn starch suspension to better perform and interpret the results obtained using CRS. The CRS data collection properties evaluated were the time to achieve steady state saturation, the direct saturation of liquid protons, generation of transverse magnetization, and dependence of the offset frequency and radio frequency (RF) field strength of longitudinal relaxation in the presence of RF saturation. Effects were evaluated for variations of input values of RF saturation field strength, apparent cross-relaxation rate, and solid longitudinal relaxation rate on the results for solid content and solid internal mobility from fitting NMR data to modified theoretical expressions. Discrepancies between fitted and stoichiometric values for the solid to liquid proton ratio were investigated. The fitting procedure used a Gaussian line shape for RF saturation of the solid-like spin system and a Lorentzian line shape for RF saturation of the liquid-spin system. Conditions under which acceptable results can be obtained with limited data sets are discussed.  相似文献   

Nutrient Seepage from Operating Turkey Buildings with a Litter System     

Zhu  Jun  Luo  Ancheng  Zhou  Yan  Ndegwa  Pius M.  Schmidt  David 《Water, air, and soil pollution》2004,151(1-4):87-101

The effect of selected nutrient amendments and temperature on the biodegradation of pentachlorophenol (PCP) within a soil biopile was studied on a laboratory scale. This was accomplished by monitoring microbial populations, the concentration of PCP and the release of inorganic chloride ions in the contaminated soil. It was found that temperatures of 10, 15 and 20 °C had no significant effect on microbial populations and the percentage of PCP remaining in the soil. However, the nutrient amendments did have a significant effect on the parameters measured. The dairy manure, ammonium nitrate fertilizer and control treatments all experienced some fluctuations in the amount of PCP remaining in the soil over the incubation period and may have been due to the release of initially unextractable bound residues. PCP decreased by 76% in the municipal solid waste compost amended soil, while the concentration of inorganic chloride ions increased. The municipal solid waste compost treatment had significantly higher bacterial and fungal populations. Based on the results of this study municipal solid waste compost may be used as an effective supplemental nutrient amendment for the degradation of PCP in soil biopiles.  相似文献   

Novel fatty acid esters of p-coumaryl alcohol in epicuticular wax of apple fruit     

Whitaker BD  Schmidt WF  Kirk MC  Barnes S 《Journal of agricultural and food chemistry》2001,49(8):3787-3792

Hexane extracts of epicuticular wax from cv. Gala apples were noted to have an unusual, broad absorbance maximum at approximately 258 nm, which led us to isolate and identify the primary UV-absorbing compounds. Column and thin-layer chromatography yielded a fraction that gave a series of paired, 260-nm-absorbing peaks on C(18) HPLC. These were shown to be a family of phenolic fatty acid esters, for which retention times increased with increasing fatty acid chain length, and paired peaks were esters of two related phenolics with the same fatty acid moiety. Alkaline hydrolysis of the esters released two water-soluble phenolics separable by C(18) HPLC. Electrospray ionization mass spectrometry gave a molecular mass of 150 for both, and (1)H NMR plus UV absorbance spectra identified them as E and Z isomers of p-coumaryl alcohol. Alkaline cleavage of the fatty acid esters in the presence of methanol or ethanol resulted in partial derivatization of E-p-coumaryl alcohol to the corresponding gamma-O-methyl or O-ethyl ether. Gradient HMQC NMR of the HPLC-purified stearate ester of E-p-coumaryl alcohol indicated that fatty acid esterification occurs at the gamma-OH rather than at the 4-OH on the phenyl ring. This is the first report of fatty acid esters of monolignols as a natural plant product.  相似文献   

Detailed physicochemical characterization of the 2S storage protein from rape (Brassica napus L.)     

Schmidt I  Renard D  Rondeau D  Richomme P  Popineau Y  Axelos MA 《Journal of agricultural and food chemistry》2004,52(19):5995-6001

Chromatographic, chemical, and spectroscopic techniques were used to characterize the physicochemical properties of napin purified by preparative chromatography. The molar extinction coefficient was determined (epsilon = 0.56), and static and dynamic light scattering measurements enabled the average molecular weight (M(w) = 13919), the second virial coefficient (A(2) = 23.95 x 10(-)(5) mol cm(3) g(-)(2)), and the hydrodynamic radius (R(H) = 1.98 nm) to be determined. No conformational changes were observed by fluorescence and circular dichroism measurements in different buffers at pH 3, 4.6, 7, and 12, confirming the high pH stability of this protein. From MALDI-TOF analysis and after enzymatic digestion, it was found that this purified sample, extracted from the rapeseed variety Express, contained mainly isoform 2SS3_BRANA.  相似文献   

Chicken egg antibodies for prophylaxis and therapy of infectious intestinal diseases. II. In vitro studies on gastric and enteric digestion of egg yolk antibodies specific against pathogenic Escherichia coli strains     

P Schmidt  V Wiedemann  R Kühlmann  R Wanke  E Linckh  U L?sch 《Zentralblatt für Veterin?rmedizin. Reihe B. Journal of veterinary medicine. Series B》1989,36(8):619-628

Specific antibodies directed against enterotoxic E. coli strains from the yolk of immunized hens were exposed in vitro to the influence of varying digestive phenomena like reduction of pH and proteolytic digestion. The remaining antibody activity was tested in a specific ELISA system. It could be shown that already within the stomach a considerable loss in antibody activity caused by a lowering of pH and peptic cleavage can be expected. A further loss in antibody activity is due to the proteolytic effect of the pancreas proteases trypsin and chymotrypsin. It was found that antibodies in protein rich solutions like egg or yolk suspensions were more resistant than mere globulin fractions or antibodies isolated by affinity chromatography. Prospects for further in vivo tests are discussed.  相似文献   

Diabetic neuropathy in dogs and cats--a bioptic electron microscopic study     

E Dahme  A Hafner  C Reusch  P Schmidt 《Tier?rztliche Praxis》1989,17(2):177-188

Electron microscopic examination of peripheral nerves within dermal corium based upon skin biopsies (punch diameter = 6 mm) of chronic diabetic dogs and cats in comparison with normal controls revealed that more than 90% of the diabetic animals (31/34 dogs, 9/10 cats) had developed characteristic neuropathies. The main features were of axonal atrophy of myelinated and unmyelinated fibers, demyelination and - to a lesser degree - intraaxonal accumulation of glycogen (about 25%). In contrast with human diabetic polyneuropathy vascular basement membranes were throughout of normal appearance. Thickening of the perineural basement membranes were observed in a few canine cases only. Diagnostic procedures as well as questions on pathogenesis are discussed in detail.  相似文献   

Inheritance of associated ocular and skeletal dysplasia in Labrador retrievers     

C B Carrig  D P Sponenberg  G M Schmidt  H W Tvedten 《Journal of the American Veterinary Medical Association》1988,193(10):1269-1272

A breeding colony was established to investigate the inheritance of associated ocular and skeletal dysplasia in Labrador Retrievers; 124 pups were produced. These pups were evaluated for the presence of ocular lesions, including cataracts, vitreous strands, persistent hyaloid remnants, retinal folds, retinal dysplasia, peripapillary hyperreflectivity, and rhegmatogenous retinal detachments, and skeletal abnormality, which was recognized by shorter than normal forelimbs and an abnormal morphologic appearance of the radius and ulna. Analysis of the distribution of lesions in pups indicated that the syndrome is caused by one abnormal gene, which has recessive effects on the skeleton and incompletely dominant effects on the eye. This would suggest that suspect carrier dogs could be identified by test matings with a known homozygote.  相似文献   

Neuroendocrine tumor (paraganglioma) in an adult bovine.     

S P Schmidt  A J Cooley 《Journal of veterinary diagnostic investigation》1992,4(2):215-217

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Toe- and footpad ulcers in fattening turkeys]     

V Schmidt  H Lüders 《Berliner und Münchener tier?rztliche Wochenschrift》1976,89(3):47-50

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