Headspace sorptive extraction (HSSE), stir bar sorptive extraction (SBSE), and solid phase microextraction (SPME) applied to the analysis of roasted Arabica coffee and coffee brew.     

Carlo Bicchi  Cristina Iori  Patrizia Rubiolo  Pat Sandra 《Journal of agricultural and food chemistry》2002,50(3):449-459

Headspace sorptive extraction (HSSE) and stir bar sorptive extraction (SBSE), two recently introduced solventless enrichment techniques, have been applied to the analysis of the headspace of Arabica roasted coffee and of the headspace of the brew and of the brew itself. In both HSSE and SBSE enrichment is performed on a thick film of poly(dimethylsiloxane) (PDMS) coated onto a magnet incorporated in a glass jacket. Sampling is done by placing the PDMS stir bar in the headspace (gas phase extraction or HSSE) or by immersing it in the liquid (liquid phase extraction or SBSE). The stir bar is then thermally desorbed on-line with capillary GC-MS. The performance of HSSE and SBSE have been compared through the determination of the recoveries and relative abundances of 16 components of the coffee volatile fraction to classical static headspace (S-HS) and to headspace and in-sample solid phase microextraction (HS-SPME and IS-SPME, respectively) applying the fibers PDMS 100 microm, Carbowax/divinylbenzene 65 microm (CW/DVB), Carboxen/PDMS 75 microm(CAR/PDMS), polyacrylate 85 microm(PA), PDMS/divinylbenzene 65 microm(PDMS/DVB), and Carboxen/divinylbenzene/PDMS 50-30 microm(CAR/PDMS/DVB). In all cases, HSSE and SBSE gave higher recoveries, and this is entirely due to the high amount of PDMS applied.  相似文献   

Hydrolases extracted from soil: Their properties and activities     

P. Nannipieri  B. Ceccanti  C. Conti  D. Bianchi 《Soil biology & biochemistry》1982,14(3):257-263

The pH optima and stabilities of some hydrolases extracted by pyrophosphate from two different soils were determined for phosphatase, urease, casein and benzoylargininamide-hydrolysing proteases. Hydrolases activities of soil extracts were more resistant to thermal denaturation than their respective commercial preparations. Extracted phosphatases exhibited a marked stability to temperature and to proteolysis.By exhaustively ultrafiltering soil extracts against 0.1 M pyrophosphate at pH 7.1 fractions of mol. wt higher and lower than 100,000 were obtained. Ultrafiltration increased the total activities of extracted ureases and phosphatases while those of casein and benzoylargininamide-hydrolysing proteases were decreased. Both on an organic C and an N basis, specific activities of ureases and phosphatases increased after ultrafiltration.  相似文献   

Presence of allergenic proteins in different peach (Prunus persica) cultivars and dependence of their content on fruit ripening   总被引：1，自引：0，他引：1  

Brenna OV  Pastorello EA  Farioli L  Pravettoni V  Pompei C 《Journal of agricultural and food chemistry》2004,52(26):7997-8000

It has been reported that various cultivars of fruits and vegetables may present a different pattern for the contained allergens. Here, we report on the different content in allergenic proteins for different peach (Prunus persica) cultivars, sampled during two consecutive harvest seasons. Fruits from six cultivars of peaches were harvested fully ripe, and the proteins extracted from whole or chemically peeled fruits were analyzed by SDS-PAGE and immunoblotting. All the protein extracts from whole fruit contained a 9 kDa protein. This protein proved to be absent in the extracts taken from chemically peeled fruit. In four cultivars, this protein corresponds to the allergen Pru p3, a lipid transfer protein that causes the oral allergy syndrome (OAS) in sensitized people. In the following year, fruits from four of the six cultivars of peaches studied previously were harvested at different times, at one and two weeks before the commercial ripening time and when fully ripe, to ascertain whether the presence of the 9 kDa allergen might be related to the ripening process. Two cultivars out of four produced an intense allergenic band corresponding to a 9 kDa protein already two weeks before the commercial ripening date, while the others showed a progressive increment of the 9 kDa allergen during ripening.  相似文献   

Effect of rotation, nitrogen fertilization and management of crop residues on some chemical, microbiological and biochemical properties of soil   总被引：4，自引：0，他引：4  

P. Perucci  U. Bonciarelli  R. Santilocchi  A. A. Bianchi 《Biology and Fertility of Soils》1997,24(3):311-316

A long-term experiment, which started in 1971 near Perugia, central Italy, was performed to investigate the effect of different crop residue management practices and rotation systems on some soil properties. Twenty years after the beginning of the experiment, chemical (organic C, total N, humified organic C, humic and fulvic acids), microbiological and biochemical parameters (microbial biomass, global hydrolase activity, dehydrogenase and catalase activities) were investigated. Two crop residue management practices were used in the experiment, i.e. removal (RCR soils) and burial (BCR soils). These treatments were factorially combined with eight rotation systems, i.e. five maize-wheat rotations of different lengths (M-1W, M-2W, M-3W, M-4W and M-5W) and three continuous wheat systems with different fertilization inputs, from 150 to 250 kg N ha^–1. Soil samples were collected in the spring of 1991 for chemical determinations, and in the spring and autumn of 1992, 1993 and 1994, for microbiological and biochemical determinations. All soil chemical, microbiological and biochemical parameters investigated showed significant differences depending on the management of the crop residues. The BCR soils showed more favourable characteristics. In contrast, few significant effects were observed in relation to rotation and N-fertilization treatment. Significant correlations were found between organic-C content and all microbiological and biochemical parameters, as well as between the microbiological and biochemical parameters themselves, indicating that organic-C content plays an important role in determining the level of soil enzyme activity and, consequently, of soil fertility. This experiment showed that burying crop residues in soil can be considered good agronomic practice, which may help limit the gradual depletion of soil organic matter and improve the chemical properties of the soil. Received: 11 January 1996  相似文献   

Erratum to: Comparative analysis of a wood-adhesive bondline     

G. Modzel  F. A. Kamke  F. De Carlo 《Wood Science and Technology》2011,45(1):159-158

The wood–adhesive interface was analyzed using five methods with the objective of quantitatively assessing penetration of adhesive into the porous wood network. Methods included fluorescence microscopy, scanning electron microscopy, backscatter electron imaging, wavelength dispersive spectroscopy, and X-ray microtomography (XMT). Each method provided a visual inspection, and all of the analysis methods were applied to the same field of view. XMT was the primary technique of interest. Rubidium hydroxide was used in place of sodium hydroxide in the formulation of phenol–formaldehyde adhesive. Rubidium was found to increase the X-ray attenuation of the adhesive. However, rubidium migrated beyond the adhesive interphase during specimen preparation, thus reducing its effectiveness for image contrast enhancement. The wood species studied included red oak (Quercus rubra), Douglas-fir (Pseudotsuga menziesii), and hybrid poplar (Populus deltoides × Populus trichocarpa). All techniques used for this study were useful, but each presented some limitations for bondline analysis. Despite the problem with rubidium migration, XMT for this application was promising.  相似文献   

Locomotor primitives in newborn babies and their development   总被引：1，自引：0，他引：1  

Dominici N  Ivanenko YP  Cappellini G  d'Avella A  Mondì V  Cicchese M  Fabiano A  Silei T  Di Paolo A  Giannini C  Poppele RE  Lacquaniti F 《Science (New York, N.Y.)》2011,334(6058):997-999

How rudimentary movements evolve into sophisticated ones during development remains unclear. It is often assumed that the primitive patterns of neural control are suppressed during development, replaced by entirely new patterns. Here we identified the basic patterns of lumbosacral motoneuron activity from multimuscle recordings in stepping neonates, toddlers, preschoolers, and adults. Surprisingly, we found that the two basic patterns of stepping neonates are retained through development, augmented by two new patterns first revealed in toddlers. Markedly similar patterns were observed also in the rat, cat, macaque, and guineafowl, consistent with the hypothesis that, despite substantial phylogenetic distances and morphological differences, locomotion in several animal species is built starting from common primitives, perhaps related to a common ancestral neural network.  相似文献   

The genome of the kinetoplastid parasite, Leishmania major     

Ivens AC  Peacock CS  Worthey EA  Murphy L  Aggarwal G  Berriman M  Sisk E  Rajandream MA  Adlem E  Aert R  Anupama A  Apostolou Z  Attipoe P  Bason N  Bauser C  Beck A  Beverley SM  Bianchettin G  Borzym K  Bothe G  Bruschi CV  Collins M  Cadag E  Ciarloni L  Clayton C  Coulson RM  Cronin A  Cruz AK  Davies RM  De Gaudenzi J  Dobson DE  Duesterhoeft A  Fazelina G  Fosker N  Frasch AC  Fraser A  Fuchs M  Gabel C  Goble A  Goffeau A  Harris D  Hertz-Fowler C  Hilbert H  Horn D  Huang Y  Klages S  Knights A  Kube M  Larke N  Litvin L  Lord A 《Science (New York, N.Y.)》2005,309(5733):436-442

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Zorrimidazolone, a bioactive alkaloid from the non-indigenous mediterranean stolidobranch Polyandrocarpa zorritensis     

Aiello A  Fattorusso E  Imperatore C  Irace C  Luciano P  Menna M  Santamaria R  Vitalone R 《Marine drugs》2011,9(6):1157-1165

Chemical analysis of the Mediterranean ascidian Polyandrocarpa zorritensis (Van Name 1931) resulted in the isolation of a series of molecules including two monoindole alkaloids, 3-indolylglyoxylic acid (3) and its methyl ester (4), 4-hydroxy-3-methoxyphenylglyoxylic acid methyl ester (1) and a new alkaloid we named zorrimidazolone (2). The structure of the novel compound 2 has been elucidated by spectroscopic analysis and bioactivity of all compounds has been investigated. Zorrimidazolone (2) showed a modest cytotoxic activity against C6 rat glioma cell line.  相似文献   

Slow fertilization of stickleback eggs: the result of sexual conflict?     

Theo CM Bakker  Marc Zbinden  Joachim G Frommen  Alexander Weiss  Carlo R Largiadèr 《BMC ecology》2006,6(1):7-8

Background  

The fertilization success in sperm competition in externally fertilizing fish depends on number and quality of sperm. The time delay between sequential ejaculations may further influence the outcome of sperm competition. Such a time interval can load the raffle over fertilization if fertilization takes place very fast. Short fertilization times are generally assumed for externally fertilizing fish such as the three-spined stickleback (Gasterosteus aculeatus). In this pair-spawning fish, territorial males often try to steal fertilizations in nests of neighbouring males. This sneaking behaviour causes sperm competition. Sneakers will only get a share of paternity when eggs are not fertilized immediately after sperm release. Contrary to males, females may be interested in multiple paternity of their clutch of eggs. There thus may be a sexual conflict over the speed of fertilization.  相似文献   

Soil Olsen P response to different phosphorus fertilization strategies in long-term experiments in NW Italy     

Michela Battisti  Barbara Moretti  Dario Sacco  Carlo Grignani  Laura Zavattaro 《Soil Use and Management》2022,38(1):549-563

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