Templating organic semiconductors via self-assembly of polymer colloids     

Mezzenga R  Ruokolainen J  Fredrickson GH  Kramer EJ  Moses D  Heeger AJ  Ikkala O 《Science (New York, N.Y.)》2003,299(5614):1872-1874

A route for producing semiconducting polymer blends is demonstrated in which a doped pi-conjugated polymer is forced into a three-dimensionally continuous minor phase by the self-assembly of colloidal particles and block copolymers. The resulting cellular morphology can be viewed as a high-internal phase polymeric emulsion. Compared with traditional blending procedures, this process reduces the percolation threshold for electrical conductivity by a factor of 10, increases the conductivity by several orders of magnitude, and simultaneously improves thermal stability. Following this route, new applications can be envisaged for semiconducting polymer blends that require only minimal concentrations of doped pi-conjugated polymer.  相似文献   

Ocean science. A frontal challenge for climate models     

Ferrari R 《Science (New York, N.Y.)》2011,332(6027):316-317

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Mechanized thinning of walnut plantations established on ex-arable land     

Natascia Magagnotti  Carla Nati  Gianni Picchi  Raffaele Spinelli 《Agroforestry Systems》2011,82(1):77-86

The study compares two product strategies—chips versus firewood—and two technological levels—manual versus mechanized—as applied to the thinning of walnut agroforestry plantations, established on ex-arable land. Such plantations are widespread all across Europe, and their establishment was subsidized under the provisions of EU Directive 2080/90, and of regional grant schemes. Field test data were used to build a simple deterministic model for estimating thinning productivity and cost under varying work and economic conditions. This model can assist prospective users when checking the profitability of an operation, or when assessing the competitiveness of alternative options. Removing nurse alder from young walnut plantations yields between 25 and 50 t of fresh biomass per hectare and is crucial to the good development of the stand. The study shows that the removal of nurse alder from walnut plantations is economically viable, and it can also offer some profits if stand and market conditions are favourable. As a rule, the average DBH of removal trees should not be smaller than 12 cm. Best results are obtained with mechanized harvesting, which does not seem to cause heavier stand and soil damage than manual harvesting. Manual harvesting is preferable only if the annual utilization of machinery is very low, and in this case it should be geared to firewood production. The manual whole-tree harvesting (WTH) method used in this study offers the lowest performance under all conditions, and should be replaced with some other manual alternative to WTH. Mechanized WTH offers a significant cost reduction over mechanized short-wood (SWS) harvesting, but this difference is still rather limited: hence, other parameters come into play when deciding what system to apply, and namely product price and mass output. In this respect, one also has to consider the cost of managing the harvesting residue, and that of fertilizing, if soil nutrient depletion is to be feared.  相似文献   

Wheat flour enzymatic amylolysis monitored by in situ (1)H NMR spectroscopy     

Amato ME  Ansanelli G  Fisichella S  Lamanna R  Scarlata G  Sobolev AP  Segre A 《Journal of agricultural and food chemistry》2004,52(4):823-831

Starch enzymatic degradation caused by endogenous hydrolases is studied by in situ NMR spectroscopy on a set of hard and soft wheat flours. The results obtained by two different techniques (HR-MAS and (1)H NMR in solution) are analyzed in terms of a Michaelis-Menten kinetic phenomenological model taking into account the presence of endogenous enzymes and their eventual inactivation. The parameters resulting from the best fit of all experimental data to the kinetic model equations are submitted to a multivariate statistical analysis to assess the role of the oligosaccharides release in distinguishing between hard and soft wheats.  相似文献   

Structure-activity relationships of derivatives of fusapyrone, an antifungal metabolite of Fusarium semitectum     

Altomare C  Pengue R  Favilla M  Evidente A  Visconti A 《Journal of agricultural and food chemistry》2004,52(10):2997-3001

Fusapyrone (1) and deoxyfusapyrone (2) are two 3-substituted-4-hydroxy-6-alkyl-2-pyrones isolated from Fusarium semitectum that have considerable antifungal activity against molds. Because of their low zootoxicity and selective action they are potentially utilizable along with biocontrol yeasts for control of postharvest crop diseases. Seven derivatives of 1 (3 and 5-10) and one derivative of 2 (4) were obtained by chemical modifications of the glycosyl residue, the 2-pyrone ring, the aliphatic chain, or a combination thereof, and a structure-activity correlation study was carried out with regard to their zootoxicity and antifungal activity. Derivatives 7-10, as well as 1, were slightly zootoxic in Artemia salina (brine shrimp) bioassays, whereas pentaacetylation of 1 into 3, 5, and 6 resulted in a strong increase in toxicity. Compound 4, the tetraacetyl derivative of 2, was as toxic as 2. Because the structural changes of 1 that resulted in an increase of biological activity in A. salina bioassay were those that affected mainly the water solubility of the molecule, it appears that toxicity is related to hydrophobicity. Compounds 1 and 2 showed strong antifungal activity toward Botrytis cinerea, Aspergillus parasiticus, and Penicilliun brevi-compactum (minimum inhibitory concentration at 24 h = 0.78-6.25 microg/mL). Among derivatives 3-10, only compounds 7, 9, and 10 retained some activity, limited to B. cinerea and at high concentration (25-50 microg/mL). None of the compounds 1-10 inhibited the growth of the biocontrol yeasts Pichia guilliermondii and Rhodotorula glutinis at the highest concentration tested (50 microg/mL).  相似文献   

Metabolite profiling of grape: Flavonols and anthocyanins     

Mattivi F  Guzzon R  Vrhovsek U  Stefanini M  Velasco R 《Journal of agricultural and food chemistry》2006,54(20):7692-7702

Flavonols are products of the flavonoid biosynthetic pathway, which also give rise to anthocyanins and condensed tannins in grapes. We investigated their presence in the berry skins of 91 grape varieties (Vitis vinifera L.), in order to produce a classification based on the flavonol profile. The presence of laricitrin 3-O-galactoside and syringetin 3-O-galactoside in red grapes is reported here for the first time. In red grapes, the main flavonol was quercetin (mean = 43.99%), followed by myricetin (36.81%), kaempferol (6.43%), laricitrin (5.65%), isorhamnetin (3.89%), and syringetin (3.22%). In white grapes, the main flavonol was quercetin (mean = 81.35%), followed by kaempferol (16.91%) and isorhamnetin (1.74%). The delphinidin-like flavonols myricetin, laricitrin, and syringetin were missing in all white varieties, indicating that the enzyme flavonoid 3',5'-hydroxylase is not expressed in white grape varieties. The pattern of expression of flavonols and anthocyanins in red grapes was compared, in order to gain information on the substrate specificity of enzymes involved in flavonoid biosynthesis.  相似文献   

Performance,Capability and Costs of Small-Scale Cable Yarding Technology     

Raffaele Spinelli  Natascia Magagnotti  Carolina Lombardini 《Small-Scale Forestry》2010,9(1):123-135

The authors tested two mini-yarders, one for uphill and the other for downhill extraction. The two machines were modern commercial models, offering state-of-the-art yarding technology on a miniature scale and at a much lower cost than required for purchasing a full-size tower yarder. The two units must not be regarded as alternative, but rather as complementary, since they offer different capabilities and advantages. Both machines were tested while harvesting firewood from the thinning of young beech stands in Central Italy. The tests indicated that both units can reach a productivity between 1.5 and 2.4 m³ SMH⁻¹, including all delays, as well as set-up and dismantle time. Calculated extraction cost ranged between 24 and over 30€ m⁻³. The authors calculated a set of regression equations for estimating machine productivity as a function of the main work conditions. The performance of the studied mini-yarders does not seem much inferior to that achieved by professional light tower yarder under the same work conditions, but the lighter construction of the small-scale units may result in a lower resistance to wear and abuse. In any case, mini-yarders seem ideal for deployment under the typical conditions of small-scale forestry, offering a good solution to wood extraction on steep terrain, competitive with animal and winch logging in terms of productivity, cost and operator comfort.  相似文献   

Performance and cost of a new mini-forwarder for use in thinning operations     

Raffaele Spinelli  Natascia Magagnotti 《Journal of Forest Research》2010,15(6):358-364

Two tests were conducted with a new model of mini-forwarder, specifically designed for thinning operations. The tested machine resembles a conventional industrial forwarder, with tandem bogies and central articulation, but is much smaller and lighter. The machine was tested on forest plantations established on ex-farm land: such plantations offer favorable and homogeneous work conditions, which allowed reasonably accurate productivity figures to be obtained with a relatively small number of observation hours (about 10.5 h). Despite the relative inexperience of the driver, the tests indicated a productivity of between 3.1 and 3.8 m³ per scheduled machine hour (SMH) over an extraction distance of about 400 m. Extraction costs ranged from 12.4 to 15.1 € m⁻³ at the calculated machine rate of 47.6 € h⁻¹. Compared to older models derived from recreation vehicles or tracked wheelbarrows, the machine tested in this study offers a better performance and a much more comfortable workplace, with the operator sitting inside an enclosed and insulated cab. Fitted with four bogies and provided with a much longer wheelbase, the new forwarder is likely to be safer than tracked machines when surmounting obstacles, and it certainly offers a much smoother ride to the operator. Nevertheless, the tested machine is still much narrower than industrial forwarders and does not enjoy the same lateral stability. Hence, the machine is ideal for sneaking between trees and climbing over obstacles, but once on a slope it must be driven straight along the grade and never across it, unless with much caution. Like all hydrostatically driven vehicles, the tested mini-forwarder is not suited to long-distance extraction (>1 km): if run at high speed for too long, its hydrostatic transmission tends to overheat, forcing the operator to make frequent stops.  相似文献   

Benefits and well-being perceived by people visiting green spaces in periods of heat stress     

Raffaele Lafortezza  Giuseppe Carrus  Giovanni Sanesi  Clive Davies 《Urban Forestry & Urban Greening》2009,8(2):97-108

In urban environments, green spaces have proven to act as ameliorating factors of some climatic features related to heat stress, reducing their effects and providing comfortable outdoor settings for people. In addition, green spaces have demonstrated greater capacity, compared with built-up areas, for promoting human health and well-being. In this paper, we present results of a study conducted in Italy and the UK with the general goal to contribute to the theoretical and empirical rationale for linking green spaces with well-being in urban environments. Specifically, the study focused on the physical and psychological benefits and the general well-being associated with the use of green spaces on people when heat stress episodes are more likely to occur. A questionnaire was set up and administered to users of selected green spaces in Italy and the UK (n=800). Results indicate that longer and frequent visits of green spaces generate significant improvements of the perceived benefits and well-being among users. These results are consistent with the idea that the use of green spaces could alleviate the perception of thermal discomfort during periods of heat stress.  相似文献   

Characterization and pathogenicity of Pestalotiopsis uvicola causing black leaf spot on carob (Ceratonia siliqua L.) in Italy     

Raffaele Carrieri  Gennaro Carotenuto  Ernesto Lahoz 《European journal of plant pathology / European Foundation for Plant Pathology》2013,137(4):655-661

During spring 2013, several carob plants (Ceratonia siliqua L.), showing symptoms of necrotic black lesions on leaves, were observed in Capri Island, Southern Italy. Acervuli, producing conidia with septa and appendages, appeared in the centre of the lesions. In this report, the identification of the causal agent of this disease was made applying Koch’s postulates. Morphological characteristics of colony (colour and mycelium appearance) and conidia (size, shape, number of septa, length and number of apical and basal appendages) were characterized to identify the pathogen. Moreover, for a rapid and unambiguous identification of the fungal species, the internal transcribed spacers, comprising the 5.8 rDNA gene (ITS1-5.8-ITS2), were amplified by PCR, using the genomic DNA extracted from the isolated colonies, and sequenced. The fungus isolated was ascribed to the species Pestalotiopsis uvicola (Speg.) Bissett. Phylogenetic analysis, performed with sequences present in GenBank database, showed that carob isolates clustered with P. uvicola isolates from North America and Italy, separately from Australian, Indian and Chinese isolates. P. uvicola isolates were pathogenic when artificially inoculated on carob leaves. To the best of our knowledge, this is the first report of P. uvicola on carob.  相似文献