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81.
Sergei Zinovyev Andrei Shelepchikov Pietro Tundo 《Applied catalysis. B, Environmental》2007,72(3-4):289-298
A multipurpose study deals with the transfer hydrogenolysis of 1,3,5-trichlorobenzene to benzene in the 2-propanol–Raney nickel system in the presence of KOH. At 70 °C, no reaction occurs without KOH or with weaker bases, e.g. amines or poorly soluble inorganic bases; however saturated KOH as well as water over 1% suppress the reaction rate, presumably due to the competitive adsorption of these species on the catalyst. The catalytic activity also drops with time because of the deposition of the solid KCl on the catalyst but can be recovered at washing the catalyst with water. The deactivation by KCl can be mitigated with the addition of promoters, e.g. quaternary ammonium salts (Aliquat 336, CTAC) or trioctylamine. Aliquat 336 also promotes hydrodechlorination in the hydrothermal system using a 10% solution of 2-propanol in water, Raney nickel and potassium carbonate as base at 150–200 °C and 10–20 bar. Under these conditions, hexachlorobenzene was also selectively dechlorinated to benzene. 相似文献
82.
High-dielectric constant oxides are the focus of intense current research. As a contribution to the rationalization of the search for candidate materials, we compare the dielectric properties obtained from first-principles linear-response calculations for two phases—the ground state bixbyite and the competing hexagonal structures—of the crystalline oxide Lu2O3. The dielectric constants of bixbyite is about 12 and that of hexagonal is about 19 (the electronic constant being about 4.5 in both cases). This difference is due almost exclusively to the vibrational properties, with minor or no influence of charge anomaly differences; as these are related mainly to oxygen vibrations, we argue that the dielectric properties of sesquioxides will be determined mostly by their preferred structure, i.e. they will be poorer for bixbyite (e.g. Y2O3) than for hexagonal (e.g. La2O3) sesquioxides. 相似文献
83.
Reports an error in the original article by G. P. Lombardo and R. Foschi (History of Psychology, 2003, 2, 123-142). In the reference list, several works by Pierre Janet were identified as being Paul Janet. The correct references are provided, where Paul Janet is identified by the initial P. and Pierre Janet is identified by the initials P. M. F.. (The following abstract of this article originally appeared in record 2003-03729-003.) Since the 1920s, the road to the acknowledgment of personality psychology as a field of scientific psychology that has individuality as its object began with the founding of the discipline by Gordon W. Allport. Historians of psychology have made serious attempts to reconstruct the cultural, political, institutional, and chronological beginnings of this field in America in the 20th century. In this literature, however, an important European tradition of psychological studies of personality that developed in France in the 2nd half of the 19th century has been overlooked. The aim of this article is to cast some light on this unexplored tradition of psychological personality studies and to discuss its influence on the development of the scientific study of personality in the United States. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
84.
This paper presents the results of an experimental and numerical study of the properties of a high-performance Portland cement paste (w/c ratio 0.37; 5% silica fume) cured at 20 °C in sealed conditions for 5 days. Properties such as electrical conductivity, strength, stiffness, porosity, Vicat penetration, and autogenous deformation were measured and modelled. The kinetics of hydration was studied by means of isothermal calorimetry. The numerical simulations were performed with CEMHYD3D, developed at the National Institute of Standards and Technology, and HYMOSTRUC, developed at the Delft University of Technology. The results of the simulations were compared with experimental data, and the match was good. Clear correlations were found among electrical conductivity, autogenous shrinkage, and connectivity of solids. 相似文献
85.
86.
Marco Gabella Riccardo Notarpietro Stefano Turso Giovanni Perona 《International journal of remote sensing》2013,34(10):2869-2878
A computer program for meteorological radar siting, previously developed for pencil‐beam antenna, long‐range, C‐band radars, has been adapted for fan‐beam antenna, short‐range, X‐band radars. The simulator uses topographic information in the form of a raster digital elevation model and a surface backscattering cross‐section per unit area at grazing angles derived from the literature. It is independent of specific radar sites and radar systems. Its use will enhance optimized scanning strategies, antenna design tailored to mountainous terrain and knowledge of land‐clutter measurements at low grazing angles. The raster‐based approach used in implementing the program makes it compatible with any desired spatial resolution. Simplicity and short simulation times have been pursued as primary goals during the planning and implementation phases of the routines. A preliminary validation of the simulator using backscattering data acquired in the Alps is presented in this letter. 相似文献
87.
Antonio Coronato Massimo Esposito Giuseppe De Pietro 《Personal and Ubiquitous Computing》2009,13(7):527-538
This paper presents semantic models, mechanisms and a service to locate mobile entities in Smart and Intelligent Environments. The key feature of the service is the semantic integration of different positioning systems that not only enables the environment to handle transparently such physical positioning systems, but also to reason on location information coming from different systems and to combine it to obtain higher context information. Indeed, the service relies on the use of ontologies and rules to define a uniform, unambiguous and well-defined model for the location information, independently of the particular positioning system. Moreover, the location service performs logic and reasoning mechanisms to provide both physical and semantic locations of mobile objects and to infer the finest granularity in the case when a mobile object is located by more than one positioning system. Finally, we present an application of the proposed approach to the case of a Smart Hospital. 相似文献
88.
Marco Riccardi Roberto Di Pietro Marta Palanques Jorge Aguilà Vila 《Computer Networks》2013,57(2):422-435
Malware is one of the main threats to the Internet security in general, and to commercial transactions in particular. However, given the high level of sophistication reached by malware (e.g. usage of encrypted payload and obfuscation techniques), malware detection tools and techniques still call for effective and efficient solutions. In this paper, we address a specific, dreadful, and widely diffused financial malware: Zeus.The contributions of this paper are manifold: first, we propose a technique to break the encrypted malware communications, extracting the keystream used to encrypt such communications; second, we provide a generalization of the proposed keystream extraction technique. Further, we propose Cronus, an IDS that specifically targets Zeus malware. The implementation of Cronus has been experimentally tested on a production network, and its high quality performance and effectiveness are discussed. Finally, we highlight some principles underlying malware—and Zeus in particular—that could pave the way for further investigation in this field. 相似文献
89.
Davide Barbagallo Angela Caponnetto Cristina Barbagallo Rosalia Battaglia Federica Mirabella Duilia Brex Michele Stella Giuseppe Broggi Roberto Altieri Francesco Certo Rosario Caltabiano Giuseppe Maria Vincenzo Barbagallo Carmelina Daniela Anfuso Gabriella Lupo Marco Ragusa Cinzia Di Pietro Thomas Birkballe Hansen Michele Purrello 《International journal of molecular sciences》2021,22(4)
Circular RNAs (circRNAs) are a large class of RNAs with regulatory functions within cells. We recently showed that circSMARCA5 is a tumor suppressor in glioblastoma multiforme (GBM) and acts as a decoy for Serine and Arginine Rich Splicing Factor 1 (SRSF1) through six predicted binding sites (BSs). Here we characterized RNA motifs functionally involved in the interaction between circSMARCA5 and SRSF1. Three different circSMARCA5 molecules (Mut1, Mut2, Mut3), each mutated in two predicted SRSF1 BSs at once, were obtained through PCR-based replacement of wild-type (WT) BS sequences and cloned in three independent pcDNA3 vectors. Mut1 significantly decreased its capability to interact with SRSF1 as compared to WT, based on the RNA immunoprecipitation assay. In silico analysis through the “Find Individual Motif Occurrences” (FIMO) algorithm showed GAUGAA as an experimentally validated SRSF1 binding motif significantly overrepresented within both predicted SRSF1 BSs mutated in Mut1 (q-value = 0.0011). U87MG and CAS-1, transfected with Mut1, significantly increased their migration with respect to controls transfected with WT, as revealed by the cell exclusion zone assay. Immortalized human brain microvascular endothelial cells (IM-HBMEC) exposed to conditioned medium (CM) harvested from U87MG and CAS-1 transfected with Mut1 significantly sprouted more than those treated with CM harvested from U87MG and CAS-1 transfected with WT, as shown by the tube formation assay. qRT-PCR showed that the intracellular pro- to anti-angiogenic Vascular Endothelial Growth Factor A (VEGFA) mRNA isoform ratio and the amount of total VEGFA mRNA secreted in CM significantly increased in Mut1-transfected CAS-1 as compared to controls transfected with WT. Our data suggest that GAUGAA is the RNA motif responsible for the interaction between circSMARCA5 and SRSF1 as well as for the circSMARCA5-mediated control of GBM cell migration and angiogenic potential. 相似文献
90.
Marta Guerini Pietro Grisoli Cristina Pane Paola Perugini 《International journal of molecular sciences》2021,22(2)
The aim of this work was the development of microstructured lipid carriers (MLC) based on chitosan (CH) and containing N-acetylcysteine (NAC), a mucolytic and antioxidant agent, to inhibit the formation of Pseudomonas aeruginosa biofilm. MLC were prepared using the high shear homogenization technique. The MLC were characterized for morphology, particle size, Z potential, encapsulation efficiency and drug release. The antioxidant properties of NAC-loaded microstructured carriers were evaluated through an in vitro spectrophotometer assay. Finally, the activity of NAC-CH-MLC on biofilm production by Pseudomonas aeruginosa was also evaluated. Results obtained from this study highlighted that the use of chitosan into the inner aqueous phase permitted to obtain microstructured particles with a narrow size range and with good encapsulation efficiency. NAC-loaded MLC showed higher antioxidant activity than the free molecule, demonstrating how encapsulation increases the antioxidant effect of the molecule. Furthermore, the reduction of biofilm growth resulted extremely high with MLC being 64.74% ± 6.2% and 83.74% ± 9.95%, respectively, at 0.5 mg/mL and 2 mg/mL. In conclusion, this work represents a favorable technological strategy against diseases in which bacterial biofilm is relevant, such as cystic fibrosis. 相似文献