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51.
Ericson LM Fan H Peng H Davis VA Zhou W Sulpizio J Wang Y Booker R Vavro J Guthy C Parra-Vasquez AN Kim MJ Ramesh S Saini RK Kittrell C Lavin G Schmidt H Adams WW Billups WE Pasquali M Hwang WF Hauge RH Fischer JE Smalley RE 《Science (New York, N.Y.)》2004,305(5689):1447-1450
Well-aligned macroscopic fibers composed solely of single-walled carbon nanotubes (SWNTs) were produced by conventional spinning. Fuming sulfuric acid charges SWNTs and promotes their ordering into an aligned phase of individual mobile SWNTs surrounded by acid anions. This ordered dispersion was extruded via solution spinning into continuous lengths of macroscopic neat SWNT fibers. Such fibers possess interesting structural composition and physical properties. 相似文献
52.
Christin Selige Monike Quirino Filip Schröter Matteo Aepli Martin Schulze 《Reproduction in domestic animals》2021,56(8):1152-1155
Egg yolk (EY, control) is an essential ingredient of diluents for boar semen cryopreservation. Pasteurized egg yolk (PEY) reduces hygienic risks in processing and is easier to standardize. The aim of this study was to evaluate the in vitro effect of PEY (treatment) on frozen-thawed boar semen. In a split-sample approach (n = 13 boars), it could be shown that there is neither an influence (p > .05) on post-thawing motility (PTM: 5, 30 and 120 min) nor on morphologically intact sperm, percentage of acrosome defects and membrane fluidity using a PEY extender compared to the control. Mitochondrial activity (p = .043), membrane integrity (p = .015) and PTM 300 min (p = .023) were slightly affected in the treatment group. Overall, sperm quality was at a high level in both experimental groups. Further studies are needed to determine the impact of PEY on the fertilizing capacity of boar ejaculates. 相似文献
53.
Fast determination of catechins and xanthines in tea beverages by micellar electrokinetic chromatography 总被引:2,自引:0,他引:2
Bonoli M Colabufalo P Pelillo M Gallina Toschi T Lercker G 《Journal of agricultural and food chemistry》2003,51(5):1141-1147
Antioxidant properties and stimulating effects of green tea are related to its content of cathechins and xanthines; tea quality evaluation is based on organoleptic tests and on the presence of those components. In this work, by a MEKC method, eight cathechins and three xanthines were quantified in some tea-based beverages. The best separation was realized using a phosphate-borate running buffer, with sodium dodecyl sulfate as micellar agent. A 40 cm capillary, a temperature of 29 degrees C, a voltage of 30 kV, and UV detection at 200 nm were used. The method showed a very good sensitivity (limit of detection ranging from 0.0011 to 0.0051 microg/mL) and was applied to real tea samples to characterize their antioxidant content. Statistical studies were performed and showed a satisfactory reliability of the data. 相似文献
54.
John. W. Snape M. John Foulkes James Simmonds Michelle Leverington Lesley J Fish Yingkun Wang Matteo Ciavarrella 《Euphytica》2007,154(3):401-408
Crops frequently display genotype × environment interaction for yield and end-use quality in response to different environments,
particularly when stresses such as water limitation and temperature are components of the interaction. Plant breeders usually
exploit this variation via phenotypic selection to develop varieties with both general and specific adaptation. However the
individual genes and physiological processes underlying the basis of general and specific adaptation have rarely been elucidated.
We are combining large-scale QTL analysis of several doubled haploid populations of wheat, grown over different environments
and seasons, with detailed physiological analysis, to dissect the genes and mechanisms responsible for yield and yield × environment
variation in adapted European winter germplasm. Analysis of populations grown under irrigated and non-irrigated conditions
on drought-prone soils has revealed individual genes showing stable and differential expression over environments, and the
analysis has also identified physiological traits that contribute to differential yield performance. Genes on the homoeologous
group 2 chromosomes were associated with flag leaf senescence (stay-green) variation and were the most significant in drought
interactions. Variation for stem soluble carbohydrate reserves was associated with the 1RS arm of the 1BL/1RS translocated
chromosome, and was positively correlated with yield under both irrigated and non-irrigated conditions, and thus general adaptability.
Separate analyses of populations grown over three seasons in England, Scotland, France and Germany revealed QTL for yield
performance showing both general and specific effects. A stable QTL on chromosome 6A, consistent in different populations,
showed significant effects over seasons and environments, whilst other QTL were specific to season and/or environments. 相似文献
55.
56.
Brian Paterson David Mann Beverley Kelly & Matteo Barchiesi 《Aquaculture Research》2007,38(14):1569-1579
Limb‐loss in crustaceans can reduce moult increment and delay or advance the timing of moulting, both aspects that are likely to impact upon soft‐shell crab production. Pond‐reared blue swimmer crabs Portunus pelagicus were harvested and maintained in a crab shedding system. The wet weight, carapace width (CW) and the occurrence of limb‐loss were assessed before stocking in the shedding system and after each of the next three moults. Many of the crabs were initially missing one or two limbs and these did not grow as much as the crabs that were intact at the start of the trial. Despite its strong correlation with wet weight, CW changes proved to be misleading. Limb‐loss reduced the %CW increment but not the per cent weight increment (where the later is calculated from the actual pre‐moult weight). Pre‐moult weight explained much of the variation in post‐moult weight, with crabs moulting to approximately double their weight. Limb‐loss reduced ‘growth’ and production from the pond because it reduced pre‐moult weight but limb‐loss did not alter the weight change on shedding a given weight of crabs, although some of that change now included regeneration of limbs. One can hypothesize that much of the size variation seen in pond‐reared crabs may be due to accumulated effects of repeated limb‐loss, rather than genetic variation. 相似文献
57.
Bonoli M Verardo V Marconi E Caboni MF 《Journal of agricultural and food chemistry》2004,52(16):5195-5200
Phenolic compounds are found in both free and bound forms in cereals. The majority is in the insoluble bound form, that is, bound to cell wall material, such as ferulic acid and its derivatives. The antioxidant properties of the phenolic compounds in grains are associated with the health benefits of grains and grain products. The extraction capacity of several solvent mixtures, for extracting free phenols from barley flours, and the possibility of employing a rapid automated solvent extraction method were studied. The extraction yield of each method was evaluated by correlating several spectrophotometric indices (absorption at 280, 320, and 370 nm and total phenolic compounds by the Folin-Ciocalteu method) with the antioxidant activities of the barley extracts (scavenging activity by the 2,2-diphenyl-1-picrylhydrazyl method). Interesting results were obtained when ethanol and acetone-based extraction mixtures were employed to extract free phenols. A comparison was made between alkaline and acid hydrolysis. The extraction yield of bound phenolic compounds increased when the digestion time for alkaline hydrolysis was prolonged. 相似文献
58.
Marangon M Sauvage FX Waters EJ Vernhet A 《Journal of agricultural and food chemistry》2011,59(6):2652-2662
Consumers expect white wines to be clear. During the storage of wines, grape proteins can aggregate to form haze. These proteins, particularly chitinases and thaumatin-like proteins (TL-proteins), need to be removed, and this is done through adsorption by bentonite, an effective but inefficient wine-processing step. Alternative processes are sought, but, for them to be successful, an in-depth understanding of the causes of protein hazing is required. This study investigated the role played by ionic strength (I) and sulfate toward the aggregation of TL-proteins and chitinases upon heating. Purified proteins were dissolved in model wine and analyzed by dynamic light scattering (DLS). The effect of I on protein aggregation was investigated within the range from 2 to 500 mM/L. For chitinases, aggregation occurred during heating with I values of 100 and 500 mM/L, depending on the isoform. This aggregation immediately led to the formation of large particles (3 μm, visible haze after cooling). TL-protein aggregation was observed only with I of 500 mM/L; it mainly developed during cooling and led to the formation of finite aggregates (400 nm) that remained invisible. With sulfate in the medium chitinases formed visible haze immediately when heat was applied, whereas TL-proteins aggregated during cooling but not into particles large enough to be visible to the naked eye. The data show that the aggregation mechanisms of TL-proteins and chitinases are different and are influenced by the ionic strength and ionic content of the model wine. Under the conditions used in this study, chitinases were more prone to precipitate and form haze than TL-proteins. 相似文献
59.
Multivariate approach to evaluate the penetrometer resistance in different tillage systems 总被引:1,自引:0,他引:1
At present, the penetrometer is the most widely used instrument for assessing in situ soil strength, one of the extrinsic factors affecting plant growth and crop productivity. In this paper we propose a method that discriminates penetrometer resistance due to different soil treatments, by means of Principal Component (PC) analysis. We hypothesized and demonstrated that penetrometer resistance values measured at different soil depths are correlated among themselves (multicollinearity). Considering measurements at each depth as different variables, PC analysis restructured data sets containing these correlated variables into a smaller number of components, whose scores were utilized in univariate analysis of variance (ANOVA) to test differences among imposed soil treatments. We applied the procedure to penetrometer resistance values measured by means of a hand-held cone penetrometer in two long-term experiments conducted in southern Italy, on durum wheat (Triticum durum Desf.) under continuous cropping. In the first trial, four different soil tillage treatments were compared; in the second, two different tillages and two residue management systems were examined. In both trials, PC analysis reduced the original 14 depths of measurements into only 4 PC's, based on correlations of their resistance values, explaining more than 80% of the total variation. Furthermore, ANOVA applied to the scores of each PC, clearly indicated treatment effects on soil strength.
The proposed method has thus allowed assemblage a posteriori of penetration resistance data into only a few significative intervals, using correlations among the measurements made at the different depths. This way, the possible resistance differences due to tillage and/or management treatments have been more easily and more unambiguously showed. 相似文献
60.
Effects of a selection of additives on in vitro ruminal methanogenesis and in situ and in vivo NDF digestibility 下载免费PDF全文
Mario Pirondini Stefania Colombini Luca Malagutti Luca Rapetti Gianluca Galassi Raffaella Zanchi Gianni Matteo Crovetto 《Animal Science Journal》2015,86(1):59-68
The effects of 18 essential oils, yeast, Quebracho tannin and Quillaja saponin on ruminal methane and gas production (GP) were studied in vitro. A lactating cow diet was incubated with rumen inoculum. Doses of the additives (mg/L) were: essential oils = 500; tannin = 67; yeast = 8.35 and 16.7; and saponin = 300. Lemongrass, estragole, eugenol, geraniol, limonen, thyme oil and thymol produced less gas (overall mean 33.8 mL/200 mg dry matter (DM)) than control (43.6 mL/200 mg DM; P < 0.001). Methane produced (mL/200 mg DM) by guaiacol (10.7), lemongrass (9.6), limonene (11.4), thyme oil (10.9) and thymol (2.1) was lower than control (12.5) (P < 0.001). Methane percentage on total GP was lower (P < 0.001) for cinnamic alcohol (25.4), guaiacol (24.5), thymol (19.7) and vanillin (26.3) than control (28.8). In a second experiment, thymol, guaiacol and yeast were added to the diet of dry fistulated cows to determine in situ neutral detergent fiber digestibility (NDFD) of six forages and in vivo dietary NDFD. Thymol and yeast decreased in situ NDFD after 24 h (33.9% and 33.5% vs. 38.1%; P = 0.008). Thymol decreased in vivo total tract NDFD (40.8% vs. 51.4%; P = 0.02). Differences in GP and methane levels were registered within classes of additives. A careful selection of additives may allow for the manipulation of ruminal fermentation. 相似文献