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  • 1
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    Sensors, Vol. 15, Pages 31069-31082: A New Missing Data Imputation Algorithm Applied to Electrical Data Loggers (2015)
    MDPI Publishing
    In: Sensors
    Details
    Publication Date: 2015-12-11
    Description: Nowadays, data collection is a key process in the study of electrical power networks when searching for harmonics and a lack of balance among phases. In this context, the lack of data of any of the main electrical variables (phase-to-neutral voltage, phase-to-phase voltage, and current in each phase and power factor) adversely affects any time series study performed. When this occurs, a data imputation process must be accomplished in order to substitute the data that is missing for estimated values. This paper presents a novel missing data imputation method based on multivariate adaptive regression splines (MARS) and compares it with the well-known technique called multivariate imputation by chained equations (MICE). The results obtained demonstrate how the proposed method outperforms the MICE algorithm.
    Electronic ISSN: 1424-8220
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Published by MDPI Publishing
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  • 2
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    [Report] Photon recycling in lead iodide perovskite solar cells (2016)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publication Date: 2016-03-25
    Description: Lead-halide perovskites have emerged as high-performance photovoltaic materials. We mapped the propagation of photogenerated luminescence and charges from a local photoexcitation spot in thin films of lead tri-iodide perovskites. We observed light emission at distances of ≥50 micrometers and found that the peak of the internal photon spectrum red-shifts from 765 to ≥800 nanometers. We used a lateral-contact solar cell with selective electron- and hole-collecting contacts and observed that charge extraction for photoexcitation 〉50 micrometers away from the contacts arose from repeated recycling between photons and electron-hole pairs. Thus, energy transport is not limited by diffusive charge transport but can occur over long distances through multiple absorption-diffusion-emission events. This process creates high excitation densities within the perovskite layer and allows high open-circuit voltages. Authors: Luis M. Pazos-Outón, Monika Szumilo, Robin Lamboll, Johannes M. Richter, Micaela Crespo-Quesada, Mojtaba Abdi-Jalebi, Harry J. Beeson, Milan Vrućinić, Mejd Alsari, Henry J. Snaith, Bruno Ehrler, Richard H. Friend, Felix Deschler
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 3
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    Sensors, Vol. 16, Pages 1467: A Hybrid Algorithm for Missing Data Imputation and Its Application to Electrical Data Loggers (2016)
    MDPI Publishing
    In: Sensors
    Details
    Publication Date: 2016-09-11
    Description: The storage of data is a key process in the study of electrical power networks related to the search for harmonics and the finding of a lack of balance among phases. The presence of missing data of any of the main electrical variables (phase-to-neutral voltage, phase-to-phase voltage, current in each phase and power factor) affects any time series study in a negative way that has to be addressed. When this occurs, missing data imputation algorithms are required. These algorithms are able to substitute the data that are missing for estimated values. This research presents a new algorithm for the missing data imputation method based on Self-Organized Maps Neural Networks and Mahalanobis distances and compares it not only with a well-known technique called Multivariate Imputation by Chained Equations (MICE) but also with an algorithm previously proposed by the authors called Adaptive Assignation Algorithm (AAA). The results obtained demonstrate how the proposed method outperforms both algorithms.
    Electronic ISSN: 1424-8220
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Published by MDPI Publishing
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  • 4
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    Sensors, Vol. 12, Pages 11811-11852: Sensor-Generated Time Series Events: A Definition Language (2012)
    MDPI Publishing
    In: Sensors
    Details
    Publication Date: 2012-08-30
    Description: There are now a great many domains where information is recorded by sensors over a limited time period or on a permanent basis. This data flow leads to sequences of data known as time series. In many domains, like seismography or medicine, time series analysis focuses on particular regions of interest, known as events, whereas the remainder of the time series contains hardly any useful information. In these domains, there is a need for mechanisms to identify and locate such events. In this paper, we propose an events definition language that is general enough to be used to easily and naturally define events in time series recorded by sensors in any domain. The proposed language has been applied to the definition of time series events generated within the branch of medicine dealing with balance-related functions in human beings. A device, called posturograph, is used to study balance-related functions. The platform has four sensors that record the pressure intensity being exerted on the platform, generating four interrelated time series. As opposed to the existing ad hoc proposals, the results confirm that the proposed language is valid, that is generally applicable and accurate, for identifying the events contained in the time series.
    Electronic ISSN: 1424-8220
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Published by MDPI Publishing
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  • 5
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    Charge extraction via graded doping of hole transport layers gives highly luminescent and stable metal halide perovskite devices (2019)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2019
    Description: 〈p〉One source of instability in perovskite solar cells (PSCs) is interfacial defects, particularly those that exist between the perovskite and the hole transport layer (HTL). We demonstrate that thermally evaporated dopant-free tetracene (120 nm) on top of the perovskite layer, capped with a lithium-doped Spiro-OMeTAD layer (200 nm) and top gold electrode, offers an excellent hole-extracting stack with minimal interfacial defect levels. For a perovskite layer interfaced between these graded HTLs and a mesoporous TiO〈sub〉2〈/sub〉 electron-extracting layer, its photoluminescence yield reaches 15% compared to 5% for the perovskite layer interfaced between TiO〈sub〉2〈/sub〉 and Spiro-OMeTAD alone. For PSCs with graded HTL structure, we demonstrate efficiency of up to 21.6% and an extended power output of over 550 hours of continuous illumination at AM1.5G, retaining more than 90% of the initial performance and thus validating our approach. Our findings represent a breakthrough in the construction of stable PSCs with minimized nonradiative losses.〈/p〉
    Electronic ISSN: 2375-2548
    Topics: Natural Sciences in General
    Published by American Association for the Advancement of Science (AAAS)
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  • 6
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    Retraction (2010)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2010-11-13
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Beloqui, Ana -- Guazzaroni, Maria Eugenia -- Pazos, Florencio -- Vieites, Jose M -- Godoy, Marta -- Golyshina, Olga V -- Chernikova, Tatyana N -- Waliczek, Agnes -- Silva-Rocha, Rafael -- Al-Ramahi, Yamal -- La Cono, Violetta -- Mendez, Carmen -- Salas, Jose A -- Solano, Roberto -- Yakimov, Michail M -- Timmis, Kenneth N -- Golyshin, Peter N -- Ferrer, Manuel -- New York, N.Y. -- Science. 2010 Nov 12;330(6006):912. doi: 10.1126/science.330.6006.912-a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21071648" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 7
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    Altered reactivity of superoxide dismutase in familial amyotrophic lateral sclerosis (1996)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1996-01-26
    Description: A subset of individuals with familial amyotrophic lateral sclerosis (FALS) possesses dominantly inherited mutations in the gene that encodes copper-zinc superoxide dismutase (CuZnSOD). A4V and G93A, two of the mutant enzymes associated with FALS, were shown to catalyze the oxidation of a model substrate (spin trap 5,5'-dimethyl-1-pyrroline N-oxide) by hydrogen peroxide at a higher rate than that seen with the wild-type enzyme. Catalysis of this reaction by A4V and G93A was more sensitive to inhibition by the copper chelators diethyldithiocarbamate and penicillamine than was catalysis by wild-type CuZnSOD. The same two chelators reversed the apoptosis-inducing effect of mutant enzymes expressed in a neural cell line. These results suggest that oxidative reactions catalyzed by mutant CuZnSOD enzymes initiate the neuropathologic changes in FALS.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wiedau-Pazos, M -- Goto, J J -- Rabizadeh, S -- Gralla, E B -- Roe, J A -- Lee, M K -- Valentine, J S -- Bredesen, D E -- AG12282/AG/NIA NIH HHS/ -- DK46828/DK/NIDDK NIH HHS/ -- GM28222/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1996 Jan 26;271(5248):515-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry and Biochemistry, University of California, Los Angeles 90095, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8560268" target="_blank"〉PubMed〈/a〉
    Keywords: Amyotrophic Lateral Sclerosis/*enzymology/genetics ; Animals ; Apoptosis/drug effects ; Binding Sites ; Catalysis ; Cell Line ; Chelating Agents/pharmacology ; Copper/metabolism ; Cyclic N-Oxides/metabolism ; Ditiocarb/pharmacology ; Humans ; Hydrogen Peroxide/metabolism ; Mutation ; Oxidation-Reduction ; Penicillamine/pharmacology ; Rats ; Superoxide Dismutase/genetics/*metabolism
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 8
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    Materials, Vol. 11, Pages 1154: Surface Modifications of Nanoparticles for Stability in Biological Fluids (2018)
    MDPI Publishing
    In: Materials
    Details
    Publication Date: 2018-07-07
    Description: Materials, Vol. 11, Pages 1154: Surface Modifications of Nanoparticles for Stability in Biological Fluids Materials doi: 10.3390/ma11071154 Authors: Luca Guerrini Ramon A. Alvarez-Puebla Nicolas Pazos-Perez Due to the high surface: volume ratio and the extraordinary properties arising from the nanoscale (optical, electric, magnetic, etc.), nanoparticles (NPs) are excellent candidates for multiple applications. In this context, nanoscience is opening a wide range of modern technologies in biological and biomedical fields, among others. However, one of the main drawbacks that still delays its fast evolution and effectiveness is related to the behavior of nanomaterials in the presence of biological fluids. Unfortunately, biological fluids are characterized by high ionic strengths which usually induce NP aggregation. Besides this problem, the high content in biomacromolecules—such as lipids, sugars, nucleic acids and, especially, proteins—also affects NP stability and its viability for some applications due to, for example, the formation of the protein corona around the NPs. Here, we will review the most common strategies to achieve stable NPs dispersions in high ionic strength fluids and, also, antifouling strategies to avoid the protein adsorption.
    Electronic ISSN: 1996-1944
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by MDPI Publishing
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  • 9
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    Reactome array: forging a link between metabolome and genome (2009)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2009-10-10
    Description: We describe a sensitive metabolite array for genome sequence-independent functional analysis of metabolic phenotypes and networks, the reactomes, of cell populations and communities. The array includes 1676 dye-linked substrate compounds collectively representing central metabolic pathways of all forms of life. Application of cell extracts to the array leads to specific binding of enzymes to cognate substrates, transformation to products, and concomitant activation of the dye signals. Proof of principle was shown by reconstruction of the metabolic maps of model bacteria. Utility of the array for unsequenced organisms was demonstrated by reconstruction of the global metabolisms of three microbial communities derived from acidic volcanic pool, deep-sea brine lake, and hydrocarbon-polluted seawater. Enzymes of interest are captured on nanoparticles coated with cognate metabolites, sequenced, and their functions unequivocally established.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Beloqui, Ana -- Guazzaroni, Maria-Eugenia -- Pazos, Florencio -- Vieites, Jose M -- Godoy, Marta -- Golyshina, Olga V -- Chernikova, Tatyana N -- Waliczek, Agnes -- Silva-Rocha, Rafael -- Al-Ramahi, Yamal -- La Cono, Violetta -- Mendez, Carmen -- Salas, Jose A -- Solano, Roberto -- Yakimov, Michail M -- Timmis, Kenneth N -- Golyshin, Peter N -- Ferrer, Manuel -- New York, N.Y. -- Science. 2009 Oct 9;326(5950):252-7. doi: 10.1126/science.1174094.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉CSIC, Institute of Catalysis, 28049 Madrid, Spain.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19815770" target="_blank"〉PubMed〈/a〉
    Keywords: Archaea/genetics/metabolism ; Bacteria/genetics/*metabolism ; Bacterial Proteins/metabolism ; Computational Biology ; Ecosystem ; Enzymes/*metabolism ; Enzymes, Immobilized ; Genome, Archaeal ; *Genome, Bacterial ; Hot Springs/microbiology ; *Metabolic Networks and Pathways ; *Metabolome ; Metabolomics/*methods ; Microarray Analysis/*methods ; Nanoparticles ; Pseudomonas putida/genetics/metabolism ; Seawater/microbiology ; Streptomyces coelicolor/genetics/metabolism ; Water Microbiology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 10
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    Photon recycling in lead iodide perovskite solar cells (2016)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2016-03-26
    Description: Lead-halide perovskites have emerged as high-performance photovoltaic materials. We mapped the propagation of photogenerated luminescence and charges from a local photoexcitation spot in thin films of lead tri-iodide perovskites. We observed light emission at distances of 〉/=50 micrometers and found that the peak of the internal photon spectrum red-shifts from 765 to 〉/=800 nanometers. We used a lateral-contact solar cell with selective electron- and hole-collecting contacts and observed that charge extraction for photoexcitation 〉50 micrometers away from the contacts arose from repeated recycling between photons and electron-hole pairs. Thus, energy transport is not limited by diffusive charge transport but can occur over long distances through multiple absorption-diffusion-emission events. This process creates high excitation densities within the perovskite layer and allows high open-circuit voltages.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pazos-Outon, Luis M -- Szumilo, Monika -- Lamboll, Robin -- Richter, Johannes M -- Crespo-Quesada, Micaela -- Abdi-Jalebi, Mojtaba -- Beeson, Harry J -- Vrucinic, Milan -- Alsari, Mejd -- Snaith, Henry J -- Ehrler, Bruno -- Friend, Richard H -- Deschler, Felix -- New York, N.Y. -- Science. 2016 Mar 25;351(6280):1430-3. doi: 10.1126/science.aaf1168.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, CB3 0HE Cambridge, UK. ; Department of Chemistry, University of Cambridge, CB2 1EW Cambridge, UK. ; Clarendon Laboratory, Department of Physics, University of Oxford, OX1 3PU Oxford, UK. ; Center for Nanophotonics, FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, Netherlands. ; Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, CB3 0HE Cambridge, UK. rhf10@cam.ac.uk fd297@cam.ac.uk.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/27013728" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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