Institution
Polytechnic University of Valencia
Education•Valencia, Spain•
About: Polytechnic University of Valencia is a education organization based out in Valencia, Spain. It is known for research contribution in the topics: Catalysis & Population. The organization has 16282 authors who have published 40162 publications receiving 850234 citations.
Papers published on a yearly basis
Papers
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TL;DR: An unsupervised robust clustering approach based on fuzzy methods is presented, which is applied to three point clouds acquired with different terrestrial laser scanners and scenarios and shows promising results.
Abstract: Terrestrial laser scanning is becoming a common surveying technique to measure quickly and accurately dense point clouds in 3-D. It simplifies measurement tasks on site. However, the massive volume of 3-D point measurements presents a challenge not only because of acquisition time and management of huge volumes of data, but also because of processing limitations on PCs. Raw laser scanner point clouds require a great deal of processing before final products can be derived. Thus, segmentation becomes an essential step whenever grouping of points with common attributes is required, and it is necessary for applications requiring the labelling of point clouds, surface extraction and classification into homogeneous areas. Segmentation algorithms can be classified as surface growing algorithms or clustering algorithms. This paper presents an unsupervised robust clustering approach based on fuzzy methods. Fuzzy parameters are analysed to adapt the unsupervised clustering methods to segmentation of laser scanner data. Both the Fuzzy C-Means (FCM) algorithm and the Possibilistic C-Means (PCM) mode-seeking algorithm are reviewed and used in combination with a similarity-driven cluster merging method. They constitute the kernel of the unsupervised fuzzy clustering method presented herein. It is applied to three point clouds acquired with different terrestrial laser scanners and scenarios: the first is an artificial (synthetic) data set that simulates a structure with different planar blocks; the second a composition of three metric ceramic gauge blocks (Grade 0, flatness tolerance ± 0.1 μm) recorded with a Konica Minolta Vivid 9i optical triangulation digitizer; the last is an outdoor data set that comes up to a modern architectural building collected from the centre of an open square. The amplitude-modulated-continuous-wave (AMCW) terrestrial laser scanner system, the Faro 880, was used for the acquisition of the latter data set. Experimental analyses of the results from the proposed unsupervised planar segmentation process are shown to be promising.
195 citations
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TL;DR: In this article, three-dimensional flow calculations of the intake and compression stroke of a four-valve direct-injection Diesel engine have been carried out with different combustion chambers.
195 citations
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TL;DR: In this article, the effect of conventional and microwave pasteurization on the main bioactive compounds of grapefruit juice and their stability during 2 months' refrigerated and frozen storage was evaluated.
195 citations
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TL;DR: The computational study indicates that the mechanism of Sn-beta and Zr-beta catalysis is similar, and involves the following steps: adsorption of both the ketone and the alcohol on the Lewis acid center, deprotonation of the alcohol, carbon-to-carbon hydride transfer, proton transfer from the catalyst, and products exchange.
Abstract: The mechanism of the Meerwein-Ponndorf-Verley (MPV) reduction of cyclohexanone with 2-butanol catalyzed by Sn-beta and Zr-beta zeolites has been theoretically investigated using density functional theory (DFT) and the cluster approach. An experimental catalytic study has shown that the active sites in the MPV reaction catalyzed by Sn-beta are the same partially hydrolyzed Sn-OH groups that were found to be active for the Baeyer-Villiger (BV) reaction. The computational study indicates that the mechanism of Sn-beta and Zr-beta catalysis is similar, and involves the following steps: adsorption of both the ketone and the alcohol on the Lewis acid center, deprotonation of the alcohol, carbon-to-carbon hydride transfer, proton transfer from the catalyst, and products exchange. As in the aluminum alkoxide catalyzed reaction, the hydride shift occurs through a six-membered transition state, and the role of the hydrolyzed and therefore more flexible M-OH bond is just to facilitate the initial deprotonation of the alcohol.
195 citations
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Abstract: Nitration of tyrosine (Y) residues of proteins is a low abundant post-translational modification that modulates protein function or fate in animal systems. However, very little is known about the in vivo prevalence of this modification and its corresponding targets in plants. Immunoprecipitation, based on an anti-3-nitroY antibody, was performed to pull-down potential in vivo targets of Y nitration in the Arabidopsis thaliana proteome. Further shotgun liquid chromatography-mass spectrometry (LC-MS/MS) proteomic analysis of the immunoprecipitated proteins allowed the identification of 127 proteins. Around 35% of them corresponded to homologues of proteins that have been previously reported to be Y nitrated in other non-plant organisms. Some of the putative in vivo Y-nitrated proteins were further confirmed by western blot with specific antibodies. Furthermore, MALDI-TOF (matrix-assisted laser desorption ionization-time of flight) analysis of protein spots, separated by two-dimensional electrophoresis from immunoprecipitated proteins, led to the identification of seven nitrated peptides corresponding to six different proteins. However, in vivo nitration sites among putative targets could not be identified by MS/MS. Nevertheless, an MS/MS spectrum with 3-aminoY318 instead of the expected 3-nitroY was found for cytosolic glyceraldehyde-3-phosphate dehydrogenase. Reduction of nitroY to aminoY during MS-based proteomic analysis together with the in vivo low abundance of these modifications made the identification of nitration sites difficult. In turn, in vitro nitration of methionine synthase, which was also found in the shotgun proteomic screening, allowed unequivocal identification of a nitration site at Y287.
195 citations
Authors
Showing all 16503 results
Name | H-index | Papers | Citations |
---|---|---|---|
Avelino Corma | 134 | 1049 | 89095 |
Bruce D. Hammock | 111 | 1409 | 57401 |
Geoffrey A. Ozin | 108 | 811 | 47504 |
Wolfgang J. Parak | 102 | 469 | 43307 |
Hermenegildo García | 97 | 792 | 46585 |
María Vallet-Regí | 95 | 711 | 41641 |
Albert Ferrando | 87 | 419 | 36793 |
Rajendra Prasad | 86 | 945 | 29526 |
J.J. Garcia-Luna-Aceves | 86 | 602 | 25151 |
George W. Huber | 84 | 280 | 37964 |
Juan J. Calvete | 81 | 458 | 22646 |
Juan M. Feliu | 80 | 544 | 23147 |
Amparo Chiralt | 78 | 298 | 18378 |
Michael Tsapatsis | 77 | 375 | 20051 |
Josep Redon | 77 | 488 | 81395 |