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排序方式: 共有111条查询结果,搜索用时 15 毫秒
1.
The control of the fungal contamination on crops is considered a priority by the sanitary authorities of an increasing number of countries, and this is also due to the fact that the geographic areas interested in mycotoxin outbreaks are widening. Among the different pre- and post-harvest strategies that may be applied to prevent fungal and/or aflatoxin contamination, fungicides still play a prominent role; however, despite of countless efforts, to date the problem of food and feed contamination remains unsolved, since the essential factors that affect aflatoxins production are various and hardly to handle as a whole. In this scenario, the exploitation of bioactive natural sources to obtain new agents presenting novel mechanisms of action may represent a successful strategy to minimize, at the same time, aflatoxin contamination and the use of toxic pesticides. The Aflatox® Project was aimed at the development of new-generation inhibitors of aflatoxigenic Aspergillus spp. proliferation and toxin production, through the modification of naturally occurring molecules: a panel of 177 compounds, belonging to the thiosemicarbazones class, have been synthesized and screened for their antifungal and anti-aflatoxigenic potential. The most effective compounds, selected as the best candidates as aflatoxin containment agents, were also evaluated in terms of cytotoxicity, genotoxicity and epi-genotoxicity to exclude potential harmful effect on the human health, the plants on which fungi grow and the whole ecosystem.  相似文献   
2.
Systems based on the service-oriented architecture (SOA) principles have become an important cornerstone of the development of enterprise-scale software applications. They are characterized by separating functions into distinct software units, called services, which can be published, requested and dynamically combined in the production of business applications. Service-oriented systems (SOSs) promise high flexibility, improved maintainability, and simple re-use of functionality. Achieving these properties requires an understanding not only of the individual artifacts of the system but also their integration. In this context, non-functional aspects play an important role and should be analyzed and modeled as early as possible in the development cycle. In this paper, we discuss modeling of non-functional aspects of service-oriented systems, and the use of these models for analysis and deployment. Our contribution in this paper is threefold. First, we show how services and service compositions may be modeled in UML by using a profile for SOA (UML4SOA) and how non-functional properties of service-oriented systems can be represented using the non-functional extension of UML4SOA (UML4SOA-NFP) and the MARTE profile. This enables modeling of performance, security and reliable messaging. Second, we discuss formal analysis of models which respect this design, in particular we consider performance estimates and reliability analysis using the stochastically timed process algebra PEPA as the underlying analytical engine. Last but not least, our models are the source for the application of deployment mechanisms which comprise model-to-model and model-to-text transformations implemented in the framework VIATRA. All techniques presented in this work are illustrated by a running example from an eUniversity case study.  相似文献   
3.
Preserving individual privacy when publishing data is a problem that is receiving increasing attention. Thanks to its simplicity the concept of k-anonymity, introduced by Samarati and Sweeney [1], established itself as one fundamental principle for privacy preserving data publishing. According to the k-anonymity principle, each release of data must be such that each individual is indistinguishable from at least k−1 other individuals.  相似文献   
4.
The experiments on the capillary breakup of slag jets at high temperatures are presented in this article. The impact of external excitations on the disintegration process was investigated in a furnace with optical access filmed at frame rates up to 10,000 fps. A synthetic calcia‐alumina slag was used to form jets at different temperatures (1570–1660°C) and jet velocities (0.6–1.4 ms?1). The impact of external vibration on the breakup was evident: for low jet velocities, the jet length decreased, the droplet size increased, satellite droplet formation was hindered, and a distinct “pumping mechanism” was observed. For jets with higher velocity, the jet length decreased by 30%, the droplet generation frequency increased from 20 to 250 droplets per second, the drop sizes were uniform, and satellite formation was also suppressed. In this case, the ideal case in which the volume of one wave instability forms one droplet was achieved. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3350–3361, 2014  相似文献   
5.
Gut microbiota encompasses a wide variety of commensal microorganisms consisting of trillions of bacteria, fungi, and viruses. This microbial population coexists in symbiosis with the host, and related metabolites have profound effects on human health. In this respect, gut microbiota plays a pivotal role in the regulation of metabolic, endocrine, and immune functions. Bacterial metabolites include the short chain fatty acids (SCFAs) acetate (C2), propionate (C3), and butyrate (C4), which are the most abundant SCFAs in the human body and the most abundant anions in the colon. SCFAs are made from fermentation of dietary fiber and resistant starch in the gut. They modulate several metabolic pathways and are involved in obesity, insulin resistance, and type 2 diabetes. Thus, diet might influence gut microbiota composition and activity, SCFAs production, and metabolic effects. In this narrative review, we discuss the relevant research focusing on the relationship between gut microbiota, SCFAs, and glucose metabolism.  相似文献   
6.
This work concerns with metal oxide (MOX) gas sensors based on nanowires and thin films. We focus on chemical warfare agents (CWAs) detection to compare these materials from the functional point-of-view. We work with different chemicals including simulants for Sarin nerve agents, vescicant gases, cyanide agents, and analytes such as ethanol, acetone, ammonia, and carbon monoxide that can be produced by everyday activities causing false alarms. Explorative data analysis has been used to demonstrate the different sensing performances of nanowires and thin films. Within the chosen application, our analysis reveal that the introduction of nanowires inside the array composed by thin films can improve its sensing capability. Cyanide simulants have been detected at concentrations close to 1 ppm, lower than the Immediately Dangerous for Life and Health (IDLH) value of the respective warfare agent. Higher sensitivity has been obtained to simulants for Sarin and vescicant gases, which have been detected at concentrations close or even lower than 100 ppb. Results demonstrate the suitability of the proposed array to selectively detect CWA simulants with respect to some compounds produced by everyday activities.  相似文献   
7.
The knowledge of the drop rise velocity in dispersed systems is of fundamental importance. Especially, the residence time is needed for calculation of mass transfer rates in extraction columns. This work deals with fluid dynamic measurements of toluene droplets rising in water ranging from 1.0 to 7.0 mm, with the premise of high purity of the used chemicals. The toluene/water‐system is widely used as a test system with high interfacial tension. A semiempirical correlation for pure systems to predict the terminal velocity of single rising/falling droplets based on experimental data is presented. Results show that a distinction between maximum and characteristic mean values of the drop rise velocity is necessary, especially in the diameter range 2.4–3.0 mm where unexpected velocity fluctuations occur. Two distinct terminal rise velocities were observed for 3 mm droplets. Furthermore, comparisons of the Weber‐Reynolds‐correlation and the drag coefficient with correlations from literature show good agreement. © 2009 American Institute of Chemical Engineers AIChE J, 2009  相似文献   
8.
Advanced treatment techniques, like ozone, activated carbon and TiO2 in combination with UV, are proposed to improve removal efficiency of micropollutants during wastewater treatment. In a meta-analysis of peer-reviewed literature, we found significantly reduced overall ecotoxicity of municipal wastewaters treated with either ozone (n = 667) or activated carbon (=113), while TiO2 and UV was not yet assessed. As comparative investigations regarding the detoxification potential of these advanced treatment techniques in municipal wastewater are scarce, we assessed them in four separate Gammarus-feeding trials with 20 replicates per treatment. These bioassays indicate that ozone concentrations of approximately 0.8 mg ozone/mg DOC may produce toxic transformation products. However, referred effects are removed if higher ozone concentrations are used (1.3 mg ozone/mg DOC). Moreover, the application of 1 g TiO2/l and ambient UV consistently reduced ecotoxicity. Although activated carbon may remove besides micropollutants also nutrients, which seemed to mask its detoxification potential, this treatment technique reduced the ecotoxicity of the wastewater following its amendment with nutrients. Hence, all three advanced treatment techniques are suitable to reduce the ecotoxicity of municipal wastewater mediated by micropollutants and may hence help to meet the requirements of the European Water Framework Directive.  相似文献   
9.
Bundschuh M  Schulz R 《Water research》2011,45(13):3999-4007
Ozone application is an effective tool to reduce loads of (micro)pollutants in wastewater, however, its ecotoxicological implications are largely unknown. Therefore, the feeding rates of a leaf-shredding invertebrate (Gammarus fossarum) exposed to secondary (=non-ozone) or ozone treated wastewater were investigated to assess potential ecotoxicological effects. Two repetitive experiments resulted in significantly higher feeding rates for gammarids exposed to ozone compared to non-ozone treated wastewater sampled from a treatment plant equipped with a full-scale ozonation. A further experiment confirmed these results also for wastewater from the same treatment plant, when ozonation was conducted at the lab-scale. However, the deviations in dissolved organic carbon profiles of ozone and non-ozone wastewater did not seem to be the driving factor for the effects observed. Two additional experiments displayed on the one hand a higher feeding rate of G. fossarum if exposed to ten-fold enriched eluates from solid phase extraction cartridges loaded with ozone compared to non-ozone treated wastewater. On the other hand, the mean feeding rate of gammarids exposed to non-ozone treated wastewater, which contained hardly any (micro)pollutants (i.e. pharmaceuticals), was at the same level as wastewater from the same source additionally treated with ozone. These results suggest that not an alteration in the organic matrix but a reduction in the load of micropollutants most likely triggered the effects in the bioassay applied. Hence, the feeding rate of G. fossarum appears to be a well-suited bioassay to indicate alterations in ecotoxicological properties of wastewater due to the application of advanced oxidation processes like ozonation.  相似文献   
10.
The natural history and management of gastric lymphomas of mucosa-associated lymphoid tissue (MALTomas) are not completely understood. Most stage I cases are now entered into prospective trials to confirm the excellent results obtained with conservative treatment, whereas current therapeutic policies are based on accumulated experience. The limits of staging work-ups may have a significant impact on prospective trials and ordinary clinical practice. The authors explore the sensitivity of computed tomography scanning in detecting perigastric adenopathy in 20 patients with gastric MALToma treated by gastrectomy. Clinical staging identified 17 patients as having stage I MALTomas and three patients as having stage II1 MALTomas. Histopathologic staging showed that 8 of 17 patients formerly diagnosed with stage I MALToma had perigastric nodal involvement, whereas the three patients with clinical stage II1 were confirmed as such. Computed tomography scanning has low sensitivity in detecting perigastric lymphadenopathy in gastric MALTomas. This leads to understaging, with a significant impact on therapeutic decision, and distorts newly acquired knowledge about the disease's natural history and management, introducing a bias in prospective clinical trials. Endoscopic ultrasonography should be tested as a staging procedure both in prospective trials and in ordinary clinical practice.  相似文献   
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