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排序方式: 共有683条查询结果,搜索用时 31 毫秒
91.
Sacchi P Chessa S Budelli E Bolla P Ceriotti G Soglia D Rasero R Cauvin E Caroli A 《Journal of dairy science》2005,88(4):1561-1568
The aim of this work was to investigate the genetic structure of the casein gene cluster in 5 Italian goat breeds and to evaluate the haplotype variability within and among populations. A total of 430 goats from Vallesana, Roccaverano, Jonica, Garganica, and Maltese breeds were genotyped at alphas1-casein (CSN1S1), alphas2-casein, (CSN1S2), beta-casein (CSN2), and kappa-casein (CSN3) loci using several genomic techniques and milk protein analysis. Casein haplotype frequencies were estimated for each breed. Principal component analysis was carried out to highlight the relationship among breeds. Allele and haplotype distributions indicated considerable differences among breeds. The haplotype CSN1S1*F- CSN1S2*F-CSN3*D occurred in all breeds with frequencies >0.100 and was the most common haplotype in the Southern breeds. A high frequency of CSN1S1*0-CSN1S2*C-CSN3*A haplotype was found in Vallesana population (0.162). Principal component analysis clearly separated the Northern and Southern breeds by the first component. The variability of the caprine casein loci and variety of resulting haplotypes should be exploited in the future using specific breeding programs aiming to preserve biodiversity and to select goat genetic lines for specific protein production. 相似文献
92.
The recent resurgence of growth studies has clearly established that technological progress and knowledge accumulation are
among the most important factors in determining the performance of regional and national economic systems. In this paper we
propose new evidence on knowledge flows across European regions based on patenting at the European Patent Office. We examine
in- and out-flows of patent citations as a proxy of knowledge connections, while looking also at their dynamics through time.
The econometric analysis is based on a model where the exchange of knowledge across regions is mainly affected by geographical
distance together with a set of spatial variables. The main result is that knowledge flows decrease as the geographical distance
between the origin and the destination region increase. Furthermore, knowledge flows tend to be higher among contiguous regions
and areas within the same country. These results prove to be robust with respect to the inclusion of other characteristics
of the origin and destination regions (production structure, economic conditions and technological efforts) as well as different
estimation methods. 相似文献
93.
Eleonora Polo Fabrizio Forlini Valerio Bertolasi Antonella Caterina Boccia Maria Carmela Sacchi 《Advanced Synthesis \u0026amp; Catalysis》2008,350(10):1544-1556
We report here the synthesis of new tethered biscyclopentadienyl and bisindenyl zirconocenes, bearing one unsaturation on the interannular bridge, and their use as self‐immobilizing catalysts. They proved to be active catalysts towards ethylene polymerization in solution, with activities comparable to those displayed by commercial rac‐Et(Ind)2ZrCl2. When tested as self‐polymerization catalysts under suitable experimental conditions, they gave colored precipitates that, once reactivated with MAO, were significantly active in ethylene polymerization, although lower than those of the corresponding catalytic systems in solution. The molecular weights of the produced polymers were similar to those obtained with the same catalysts in solution, but their distribution resulted to be broader, with values typical of heterogeneous catalytic systems. From 13C NMR studies we had the first spectroscopic evidence of the actual incorporation of a metallocene of this type into a polymeric chain. 相似文献
94.
Lucente M. Rossi T. Jebril A. Ruggieri M. Pulitano S. Iera A. Molinaro A. Sacchi C. Zuliani L. 《Systems Journal, IEEE》2008,2(1):90-103
W-band (75-110 GHz) is proposed nowadays as a valuable alternative to intensively-exploited Ku- and Ka-bands for high-speed transmission over satellite networks. In such a framework, some experiments are being carried out, which are targeted to verify the feasibility of exploitation of W-band for broadband service deployment. From a theoretical viewpoint, the large bandwidth availability and the scarce amount of interference typical of W-band should guarantee high capacities. Nevertheless, many crucial aspects are still to be carefully investigated, e.g., signal propagation issues, RF impairments, choice of modulation and coding, efficient antenna design, etc. In this paper, an overview is made on the low Earth orbit (LEO) nano-satellite mission in-orbit key-test and validation of W-band (IKNOW). IKNOW mission is an ongoing advanced feasibility study part of an Italian Space Agency Project, named W-band analysis and verification (WAVE), coordinated by the Department of Electronic Engineering, University of Rome ldquoTor Vergatardquo. The main objective of the IKNOW mission is to tackle some of the unexplored critical aspects concerning W-band satellite transmission. In such a perspective, IKNOW should be regarded as a ldquopilot mission,rdquo whose results will be used for a first uplink-downlink satellite channel characterization, in-orbit validation of W-band technology, and space qualification processes. This paper is focused on the research work carried out in a preliminary phase of the IKNOW study and will also consider a number of elements related to the mission configuration, payload architecture, link analysis, potential RF impairment factors, and atmospheric effects. Proposed analysis and preliminary results shown can provide to interested readers the basic guidelines that will drive the practical implementation of IKNOW mission, as well as the most relevant issues to be faced by future developers of W-band missions using small LEO satellites. 相似文献
95.
Chiara Agrati Alessandra Sacchi Eleonora Tartaglia Alessandra Vergori Roberta Gagliardini Alessandra Scarabello Michele Bibas 《International journal of molecular sciences》2021,22(15)
In severe COVID-19, which is characterized by blood clots and neutrophil-platelet aggregates in the circulating blood and different tissues, an increased incidence of cardiovascular complications and venous thrombotic events has been reported. The inflammatory storm that characterizes severe infections may act as a driver capable of profoundly disrupting the complex interplay between platelets, endothelium, and leukocytes, thus contributing to the definition of COVID-19-associated coagulopathy. In this frame, P-selectin represents a key molecule expressed on endothelial cells and on activated platelets, and contributes to endothelial activation, leucocyte recruitment, rolling, and tissue migration. Briefly, we describe the current state of knowledge about P-selectin involvement in COVID-19 pathogenesis, its possible use as a severity marker and as a target for host-directed therapeutic intervention. 相似文献
96.
Policicchio Alfonso Putz Ana-Maria Conte Giuseppe Stelitano Sara Bonaventura Carlo Poselle Ianăşi Cătălin Almásy László Wacha András Horváth Zsolt Endre Agostino Raffaele G. 《Journal of Porous Materials》2021,28(4):1049-1058
Journal of Porous Materials - The present study reports a systematic analysis of morphology and hydrogen sorption capacity of mesoporous organic-inorganic silica prepared by varying the silica... 相似文献
97.
98.
Matteo Bordiga Raffaele Guzzon Roberto Larcher Fabiano Travaglia Marco Arlorio Jean Daniel Coïsson 《International Journal of Food Science & Technology》2020,55(2):559-568
Wine is a fermented beverage that could be affected by high concentrations of biogenic amines, thus altering organoleptic and health properties. In this work, the capacity of different selected yeast strains regarding to affect the content of tyramine, histamine, 2-phenylethylamine, tryptamine and their precursor amino acids (pAA) during fermentation has been described. Overall, biogenic amines (BAs) and pAA contents appeared significantly related both to the strain and to the nutrient supplementation applied. Among BAs, without and (with) nitrogen source addition, the concentrations covered a range between 0.1 and 9.5 (0.1–10.3) mg L−1 for tyramine; 0.1 and 4.4 (0.1–4.6) mg L−1 for histamine; 0.4 and 1.1 (0.4–1.4) mg L−1 for 2-phenylethylamine; and 0.02 and 0.14 (0.01–0.12) mg L−1 for tryptamine, respectively. Considering that also wine yeast species are responsible for BAs formation, the evidence from fermentation trials underlined the relevance of a careful choice of ADY strains and nitrogen sources in the management of alcoholic fermentation in wine. 相似文献
99.
Raffaele Romano Alessandra Aiello Fabiana Pizzolongo Andrea Rispoli Lucia De Luca Paolo Masi 《International Journal of Food Science & Technology》2020,55(10):3334-3342
Tomato waste is characterised by high amounts of bioactive compounds, such as carotenoids, polyphenols and essential fatty acids. In this work, oleoresins were produced from tomato waste (skins + seeds) and skins using carbon dioxide under liquid and supercritical conditions. The use of ethanol as a co-solvent was also evaluated. Compositions of the oleoresins were analysed and compared to oleoresin obtained by means of an organic solvent, which was used as the control. Oleoresin extraction from the waste by liquid and supercritical CO2 provided the highest yields (12.5%–12.9%). The extracts obtained from the skins with supercritical CO2 without ethanol had the highest content of α- and γ-tocopherols (80 and 575 mg/100 g oleoresin, respectively), while lycopene and β-carotene were found at 205 and 75 mg/100 g oleoresin, respectively. The highest quantity of polyphenols (9305 mg GAE/100 g oleoresin) was found in the oleoresin extracted from skin by supercritical CO2 with ethanol. All oleoresins were characterised by a high antioxidant activity, which improved with the synergy of carotenoids, tocopherols and polyphenols. 相似文献
100.
Orsini F Santacroce M Perego C Lenardi C Castagna M Mari SA Sacchi VF Poletti G 《Microscopy research and technique》2006,69(10):826-834
We used atomic force microscopy (AFM) to characterize the plasma membrane of Xenopus laevis oocytes. The samples were prepared according to novel protocols, which allowed the investigation of the extra- and intracellular sides of the membrane, both of which showed sparsely distributed spherical-like protrusions. Regions with comparably sized and densely packed structures arranged in an orderly manner were visualized and dimensionally characterized. In particular, two different arrangements, hexagonal and square packing, were recognizable in ordered regions. The lateral dimension of structures visualized on the external side had a normal distribution centered on 25.5 +/- 0.3 nm (mean value +/- SE), whereas that on the intracellular side showed a normal distribution centered on 30.2 +/- 0.8 nm. The height of the protrusions was 2-5 nm on the external side and 1-3 nm on the intracellular side. The mean number of structures on the external and intracellular sides of the plasma membrane was about 1000 microm(-2) and 850 microm(-2) respectively. Trypsin treatment greatly decreased the size of the membrane protrusions, thus confirming the proteic nature of the structures. These results show that AFM is a useful tool for structural characterization of proteins in a native eukaryotic membrane. 相似文献