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41.
In a suspension of reverse micelles, in which the surfactant sodium dioctyl sulfosuccinate (AOT) separates a water nanodroplet from a bulk nonpolar CCl4 phase, ultrafast vibrational spectroscopy was used to study vibrational energy transfer from the nanodroplet through the AOT interfacial monolayer to the surrounding CCl4. Most of the vibrational energy from the nanodroplet was transferred to the polar AOT head group within 1.8 picoseconds and then out to the CCl4 within 10 picoseconds. Vibrational energy pumped directly into the AOT tail resulted in a slower 20- to 40-picosecond transfer of energy to the CCl4. 相似文献
42.
Elisabete Yurie Sataque Ono Elaine Cunha Moreno Mario Augusto Ono Carolina Nachi Rossi Gervásio Hitoshi Saito Édio Vizoni Yoshitsugu Sugiura Elisa Yoko Hirooka 《European journal of plant pathology / European Foundation for Plant Pathology》2011,131(4):653-660
In this study the effect of different cropping systems and crop successions was evaluated on natural Fusarium sp. contamination and fumonisin levels in corn. The cropping systems consisted of a conventional and no-tillage area cultivated
with corn in the summer following either oats or fallow in the winter (2006 and 2007 growing seasons). In addition, the effect
of applying nitrogen fertilizer (0, 22.5, 45.0, 90.0 and 90.0 kg ha−1 nitrogen supplemented with potassium oxide) on fumonisin contamination was evaluated in the 2006 growing season. Fusarium sp. was detected in 90% samples in 2006 and in 100% samples in 2007. In both growing seasons, no-till corn following oats
showed the highest mean fumonisin levels and differed significantly (P < 0.05) from all the others (2006) and from conventional till corn following either oats or fallow in the winter (2007).
Fumonisin levels ranged from 0.13 to 19.52 μg g−1 (mean 6.97 μg g−1) and from 3.70 to 7.75 μg g−1 (mean 6.29 μg g−1) in no-till corn following oats from the 2006 and 2007 growing seasons, respectively. Plots treated with 0 kg ha−1 and 22.5 kg ha−1 nitrogen showed the highest mean fumonisin levels and differed significantly from those with 45.0 and 90 kg ha−1 nitrogen. Fumonisin levels correlated negatively (P < 0.05) with the nitrogen fertilization rates. Although no-till is advantageous from a soil conservation standpoint, it may
enhance the potential for fumonisin contamination in corn. 相似文献
43.
Emanuela Manno Massimo Vassallo Daniela Varrica Gaetano Dongarrà Sergio Hauser 《Water, air, and soil pollution》2007,178(1-4):179-193
In the study area physical and chemical factors control the composition of surface and groundwaters, which in turn determine the water quality of the “Biviere di Gela” lake. These factors combine to create diverse water types which change their compositional character spatially as rainfall infiltrates the soil zone, moves down a topographically defined flow path, and interacts with bedrock minerals. Low-salinity waters, which represent the initial stage of underground circulation, start dissolving calcium carbonate from the local rocks. The progressive increase in salinity, characterized by substantially higher Ca, SO4, Na and Cl concentrations, suggests that dissolution of CaSO4 and NaCl is an important process during water–rock interactions. The “Biviere di Gela” lake is often separated into two units (Lago Grande and Lago Piccolo). “Lago Grande” water is generally of Na-SO4-Cl-type, whereas “Lago Piccolo” water is of Na-Cl-SO4-type. Their total content of dissolved salts varies with season, the amount of rainfall, and inflow of ground and drainage water. Over time, an increasing trend towards greater salinity and also sudden changes in the relative abundances of Cl and SO4 have been recorded for the “Lago Grande.” The isotope composition of the lake water appears to be affected by inflow of ground and surface waters and also by evaporative loss. The nitrate content of waters from the recharge basin is of particular concern because it contributes to lake eutrophication. The trace element contents do not evidence the presence of any significant metal contamination of lake waters, although a future potential hazard of metals bioaccumulation by the aquatic biota must be taken into consideration. Finally, a water balance for the basin shows that a drop in precipitation of about 20% might be critical for lake survival. 相似文献
44.
Comparative contents of dietary fiber, total phenolics, and minerals in persimmons and apples 总被引:3,自引:0,他引:3
Gorinstein S Zachwieja Z Folta M Barton H Piotrowicz J Zemser M Weisz M Trakhtenberg S Màrtín-Belloso O 《Journal of agricultural and food chemistry》2001,49(2):952-957
Dietary fibers, major phenolics, main minerals, and trace elements in persimmons and apples were analyzed and compared in order to choose a preferable fruit for an antiatherosclerotic diet. Fluorometry and atomic absorption spectrometry following microwave digestion were optimized for the determination of major phenolics and minerals. Total, soluble, and insoluble dietary fibers, total phenols, epicatechin, gallic and p-coumaric acids, and concentrations of Na, K, Mg, Ca, Fe, and Mn in whole persimmons, their pulps, and peels were significantly higher than in whole apples, pulps, and peels (P < 0.01-0.0025). Conversely, the contents of Cu and Zn were higher in apples than in persimmons. In persimmons and apples all of the above components were higher in their peels than in whole fruits and pulps. The relatively high contents of dietary fibers, total and major phenolics, main minerals, and trace elements make persimmon preferable for an antiatherosclerotic diet. 相似文献
45.
Robson Thiago Xavier de Sousa Gaspar Henrique Korndörfer Rogério Augusto Brem Soares Patrícia Rezende Fontoura 《Journal of plant nutrition》2015,38(9):1444-1455
Phosphate applications are still rare in sugarcane cultivation and can be done with phosphorus fertilizers of residual over. This study aims to evaluate the agronomic efficiency of phosphate fertilization before sugarcane planting and its effect on sugarcane yield. The study was carried out over three crop cycles at the Jalles Machado sugar-mill in Goianésia, GO, Brazil. The treatments consisted of five different phosphorus sources (soluble and insoluble) applied at a rate of 300 kg ha?1 phosphorus pentoxide (P2O5). The phosphorus fertilizers used were: triple superphosphate, mono-ammonium phosphate (MAP), Arad rock phosphate, Itafós rock phosphate, and magnesium term phosphate. The effects of these fertilizers were evaluated by plant height (ground to Top Visible Dewlap; TVD), leaf phosphorus content, agronomic efficiency, and sugarcane yield from cane-plants, first ratoon, and second ratoon. Magnesium term phosphate and triple superphosphate resulted in greater plant-cane height. Leaf phosphorus concentrations were highest with applications of MAP, magnesium term phosphate, and triple superphosphate. Phosphate applications did not affect sugarcane plant yield, but did increase ratoon yield. In general, the residual effect of insoluble phosphate increased over the years. The agronomic efficiency (AE) of phosphate was (in descending order): triple superphosphate (100%), term phosphate (89%), MAP (80%), Itafós rock phosphate (67%), and Arad rock phosphate (60%). 相似文献
46.
47.
Silvana Creste Augusto Tulmann Neto Roland Vencovsky Sebastião de Oliveira Silva Antonio Figueira 《Genetic Resources and Crop Evolution》2004,51(7):723-733
Banana (Musa spp.) is one of the most consumed fruits worldwide. Production is based mainly on triploid cultivars, and most genetic improvement programs aim to generate tetraploid hybrids obtained from the crossing of established triploid cultivars with a diploid parent genotype, improved or wild, exhibiting the trait of interest, normally resistance to biotic factors. Microsatellites were used to investigate the genetic variability and relationships between 58 Musa genotypes, including 49 diploids and nine triploid cultivars maintained at the Musa germplasm collection of the Brazilian dessert banana breeding program. Thirty-three primer pairs developed for banana were tested, and nine amplified reproducible and discrete fragments, producing a total of 115 alleles. The average number of alleles amplified per primer was 12.8, ranging from 10 to 15. The diploid genotypes presented the largest genetic variability, demonstrated by the large number of alleles detected, and the low similarity between the clones. The phenetic analysis clustered the triploid cultivars in a separated group, with the exception of the Nanica and Gros Michel cultivars, which showed high similarity with the diploid cultivar Mambee Thu. It was not possible to separate the wild diploid genotypes from the cultivated ones, indicating a common origin of these genotypes. A high proportion of duplicated alleles and/or loci was observed for diploid and triploid genotypes. The information gathered about the similarity between diploid and triploid accessions will help to define potential crosses to maximize the recovery of the typical fruit qualities required in Brazil (AAB, Pome and Silk dessert banana). 相似文献
48.
Regula G Lo Fo Wong DM Ledergerber U Stephan R Danuser J Bissig-Choisat B Stärk KD 《Preventive veterinary medicine》2005,70(1-2):29-43
An ideal national resistance monitoring program should deliver a precise estimate of the resistance situation for a given combination of bacteria and antimicrobial at a low cost. To achieve this, decisions need to be made on the number of samples to be collected at each of different possible sampling points. Existing methods of sample size calculation can not be used to solve this problem, because sampling decisions do not only depend on the prevalence of resistance and sensitivity and specificity of resistance testing, but also on the prevalence of the bacteria, and test characteristics of isolation of these bacteria. Our aim was to develop a stochastic simulation model that optimized a national resistance monitoring program, taking multi-stage sampling, imperfect sensitivity and specificity of diagnostic tests, and cost-effectiveness considerations into account. The process of resistance testing of Campylobacter spp. isolated from cloacal swab samples from poultry was modeled using a Markov Chain Monte Carlo model. Different sampling scenarios on the number of flocks to be tested, the number of birds from each flock, and the number of campylobacter colonies submitted to susceptibility testing were evaluated regarding the precision of the resulting prevalence estimate. Precision of the prevalence estimate was defined as the absolute difference between apparent and true prevalence of resistance. A partial budget approach was utilized to find the most cost-effective combination of samples to obtain a defined precision of the prevalence estimate. For a sampling scenario testing 100 flocks, five birds per flock, and one campylobacter colony per sample, the median error of the prevalence estimate was 2.5%, and 95% of the simulations resulted in an error of 7% or less. When the total number of samples was kept constant, maximizing the number of flocks tested, and only testing one bird per flock resulted in the most precise prevalence estimate. Submitting more than one campylobacter colony to resistance testing did not improve the prevalence estimate. Partial budget analysis indicated that the most cost-effective strategy was testing of two birds per flock, and submitting one colony per sample to resistance testing. 相似文献
49.
Rita?MusettiEmail author Luigi?Sanità?di Toppi Marta?Martini Francesca?Ferrini Alberto?Loschi Maria?Augusta?Favali Ruggero?Osler 《European journal of plant pathology / European Foundation for Plant Pathology》2005,112(1):53-61
Hydrogen peroxide (H2O2) localization and roles of peroxidases, malondialdehyde and reduced glutathione were compared in leaves of apricot (Prunus armeniaca) plants asymptomatic, European Stone Fruits Yellows (ESFY)-symptomatic and recovered. Nested PCR analysis revealed that Candidatus Phytoplasma prunorum, is present in asymptomatic, symptomatic and recovered apricot trees, confirming previous observations on this species, in which recovery does not seem to be related to the disappearance of phytoplasma from the plant.H2O2was detected cytochemically by its reaction with cerium chloride, which produces electron-dense deposits of cerium perhydroxides. H2O2was present in the plasmalemma of the phloem cells of recovered apricot plant leaves, but not in the asymptomatic or symptomatic material. Furthermore, by labelling apricot leaf tissues with diaminobenzidine DAB, no differences were found in the localization of peroxidases.Protein content in asymptomatic, symptomatic and recovered leaves was not significantly different from one another. In contrast, guaiacol peroxidase activity had the following trend: symptomatic > recovered > asymptomatic, whereas reduced glutathione content followed the opposite trend: asymptomatic > recovered > symptomatic. Moreover, no differences were observed in malondialdehyde concentrations between asymptomatic, symptomatic and recovered leaves. The overall results suggest that H2O2 and related metabolites and enzymes appear to be involved in lessening both pathogen virulence and disease symptom expression in ESFY-infected apricot plants. 相似文献
50.
Pecinali NR Gomes RN Amendoeira FC Bastos AC Martins MJ Pegado CS Bastos OM Bozza PT Castro-Faria-Neto HC 《Veterinary parasitology》2005,134(1-2):121-130
Toxocara canis is a nematode of the Ascaridae family that normally parasites the small intestine of canid species. Humans are accidentally infected upon ingestion of embryonated eggs, and can manifest several clinical alterations such as fever, hepatomegaly, splenomegaly, respiratory symptoms, muscle pain and anorexia. In the present work, we investigated the kinetics of tissue distribution of L2 larva in lungs, liver, kidney, brain, skeletal muscle and myocardium. Also, we analyzed the blood and bronchoalveolar lavage fluid (BAL) for levels of IL-6, IFN-gamma, eotaxin and Regulated on Activation Normal T Cell Expressed and Secreted (RANTES) in experimental murine T. canis infection. We observed liver, lung and kidney lesions correlated to larva migration as early as the first day of infection. After the seventh post-infection day, larva could also be detected in brain, skeletal muscle and heart, as an indicator of biphasic migration pattern. Increased inflammatory activity was detected in BAL and plasma of infected animals, as was an intense eosinophil migration associated with an increase in the levels of all the cytokines studied. In conclusion, our results establish a tight correlation between tissue lesions caused by larva migration and increased plasma levels of pro-inflammatory and eosinophil chemotactic cytokines. Thus, murine T. canis infection may prove to be useful in understanding the role of cytokines in infection. 相似文献