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  1. Article ; Online: Evidence of carbon-supported porphyrins pyrolyzed for the oxygen reduction reaction keeping integrity.

    Orellana, Walter / Loyola, César Zúñiga / Marco, José F / Tasca, Federico

    Scientific reports

    2022  Volume 12, Issue 1, Page(s) 8072

    Abstract: Fe(III) 5,10,15,20-(tetraphenyl)porphyrin chloride (FeTPP) and Co(III) 5,10,15,20-(tetraphenyl)porphyrin chloride (CoTPP) were adsorbed on carbon Vulcan and studied as electrocatalysts for the oxygen reduction reaction (ORR) before and after pyrolysis. ... ...

    Abstract Fe(III) 5,10,15,20-(tetraphenyl)porphyrin chloride (FeTPP) and Co(III) 5,10,15,20-(tetraphenyl)porphyrin chloride (CoTPP) were adsorbed on carbon Vulcan and studied as electrocatalysts for the oxygen reduction reaction (ORR) before and after pyrolysis. The pyrolysis process was also simulated through ab initio molecular dynamic simulations and the minimum energy path for the O
    MeSH term(s) Carbon ; Chlorides ; Ferric Compounds/chemistry ; Oxidation-Reduction ; Oxygen/chemistry ; Porphyrins/chemistry
    Chemical Substances Chlorides ; Ferric Compounds ; Porphyrins ; Carbon (7440-44-0) ; Oxygen (S88TT14065)
    Language English
    Publishing date 2022-05-16
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-022-11820-6
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Energetics and diffusion of liquid water and hydrated ions through nanopores in graphene: ab initio molecular dynamics simulation.

    Guerrero-Avilés, Raúl / Orellana, Walter

    Physical chemistry chemical physics : PCCP

    2017  Volume 19, Issue 31, Page(s) 20551–20558

    Abstract: The energetics and diffusion of water molecules and hydrated ions ( ... ...

    Abstract The energetics and diffusion of water molecules and hydrated ions (Na
    Language English
    Publishing date 2017-08-09
    Publishing country England
    Document type Journal Article
    ZDB-ID 1476244-4
    ISSN 1463-9084 ; 1463-9076
    ISSN (online) 1463-9084
    ISSN 1463-9076
    DOI 10.1039/c7cp03449k
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: FoxA1/2-dependent epigenomic reprogramming drives lineage switching in lung adenocarcinoma.

    Gillis, Katherine / Orellana, Walter A / Wilson, Emily / Parnell, Timothy J / Fort, Gabriela / Dadzie, Headtlove Essel / Zhang, Xiaoyang / Snyder, Eric L

    bioRxiv : the preprint server for biology

    2023  

    Abstract: The ability of cancer cells to alter their identity is essential for tumor survival and progression. Loss of the pulmonary lineage specifier NKX2-1 within KRAS-driven lung adenocarcinoma (LUAD) enhances tumor progression and results in a pulmonary-to- ... ...

    Abstract The ability of cancer cells to alter their identity is essential for tumor survival and progression. Loss of the pulmonary lineage specifier NKX2-1 within KRAS-driven lung adenocarcinoma (LUAD) enhances tumor progression and results in a pulmonary-to-gastric lineage switch that is dependent upon the activity of pioneer factors FoxA1 and FoxA2; however, the underlying mechanism remains largely unknown. Here, we show that FoxA1/2 reprogram the epigenetic landscape of NKX2-1-negative LUAD to facilitate a gastric identity. After
    Language English
    Publishing date 2023-11-02
    Publishing country United States
    Document type Preprint
    DOI 10.1101/2023.10.30.564775
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Self-compensation in chlorine-doped CdTe.

    Orellana, Walter / Menéndez-Proupin, Eduardo / Flores, Mauricio A

    Scientific reports

    2019  Volume 9, Issue 1, Page(s) 9194

    Abstract: Defect energetics, charge transition levels, and electronic band structures of several Cl-related complexes in CdTe are studied using density-functional theory calculations. We investigate substitutional chlorine ( ... ...

    Abstract Defect energetics, charge transition levels, and electronic band structures of several Cl-related complexes in CdTe are studied using density-functional theory calculations. We investigate substitutional chlorine (Cl
    Language English
    Publishing date 2019-06-24
    Publishing country England
    Document type Journal Article
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-019-45625-x
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  5. Article: Noncovalent functionalization of carbon nanotubes and graphene with tetraphenylporphyrins: stability and optical properties from ab initio calculations

    Orellana, Walter / Correa, Julián D

    Journal of materials science. 2015 Jan., v. 50, no. 2

    2015  

    Abstract: The stability, electronic and optical properties of single-walled carbon nanotubes (CNTs) and graphene noncovalently functionalized with free-base tetraphenylporphyrin (TPP) molecules is addressed by density functional theory calculations, including ... ...

    Abstract The stability, electronic and optical properties of single-walled carbon nanotubes (CNTs) and graphene noncovalently functionalized with free-base tetraphenylporphyrin (TPP) molecules is addressed by density functional theory calculations, including corrections to dispersive interactions. We study the TPP physisorption on 42 CNT species, particularly those with chiral indices (n,m), where 5≤n≤12 and 0≤m≤n. Our results show a quite strong π-π interaction between TPP and the CNT surface, with binding energies ranging from 1.1 to 1.8 eV, where higher energies can be associated with increasing CNT diameters. We also find that the TPP optical absorptions would not be affected by the CNT diameter or chirality. Results for the TPP physisorption on graphene show a remarkable stability with binding energy of 3.2 eV, inducing a small redshift on the π-stacked TPP absorption bands. The strong graphene-TPP interaction also induces a charge transfer from TPP to graphene, indicating a n-type doping mechanism without compromising the graphene structure.
    Keywords absorption ; carbon nanotubes ; energy ; graphene ; optical properties ; stereoisomerism
    Language English
    Dates of publication 2015-01
    Size p. 898-905.
    Publishing place Springer-Verlag
    Document type Article
    ZDB-ID 2015305-3
    ISSN 1573-4803 ; 0022-2461
    ISSN (online) 1573-4803
    ISSN 0022-2461
    DOI 10.1007/s10853-014-8650-0
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  6. Article: Cluster Assembled Silicon-Lithium Nanostructures: A Nanowire Confined Inside a Carbon Nanotube.

    Orellana, Walter / Pino-Rios, Ricardo / Yañez, Osvaldo / Vásquez-Espinal, Alejandro / Peccati, Francesca / Contreras-García, Julia / Cardenas, Carlos / Tiznado, William

    Frontiers in chemistry

    2021  Volume 9, Page(s) 767421

    Abstract: We computationally explore an alternative to stabilize one-dimensional (1D) silicon-lithium nanowires (NWs). The ... ...

    Abstract We computationally explore an alternative to stabilize one-dimensional (1D) silicon-lithium nanowires (NWs). The Li
    Language English
    Publishing date 2021-11-12
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2711776-5
    ISSN 2296-2646
    ISSN 2296-2646
    DOI 10.3389/fchem.2021.767421
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  7. Article: Insights into the electronic structure of Fe penta-coordinated complexes. Spectroscopic examination and electrochemical analysis for the oxygen reduction and oxygen evolution reactions

    Loyola, César Zúñiga / Abarca, Gabriel / Ureta-Zañartu, Soledad / Aliaga, Carolina / Zagal, Jose H. / Sougrati, Moulay Tahar / Jaouen, Frédéric / Orellana, Walter / Tasca, Federico

    Journal of materials chemistry A. 2021 Nov. 2, v. 9, no. 42

    2021  

    Abstract: Fe phthalocyanine was coordinated to pyridine-modified carbon nanotubes and studied as a catalyst for the oxygen reduction (ORR) and oxygen evolution reactions (OER). X-ray photoelectron spectroscopy (XPS), Mössbauer, and electron paramagnetic resonance ... ...

    Abstract Fe phthalocyanine was coordinated to pyridine-modified carbon nanotubes and studied as a catalyst for the oxygen reduction (ORR) and oxygen evolution reactions (OER). X-ray photoelectron spectroscopy (XPS), Mössbauer, and electron paramagnetic resonance spectroscopy (EPR) analysis supported that pyridine acts as an axial ligand to yield penta-coordinated catalytic active Fe sites. The impedance analyses show an increase in the double-layer capacitance (Cdₗ) value, corroborating the adsorption of the complexes to give FePc-Py-CNT. The evaluation of the electrocatalytic activity for the ORR was performed in both acid (0.1 M H₂SO₄) and basic (0.1 M KOH) media, while the evaluation of the OER activity was investigated only in alkaline medium. DFT studies revealed an increased length in the Fe–N binding of the pentacoordinate Fe-based site, leading to a decreased O₂–Fe binding energy, explaining the higher ORR and OER activity of FePc-Py-CNT relative to FePc-CNT.
    Keywords X-ray photoelectron spectroscopy ; adsorption ; capacitance ; carbon nanotubes ; catalysts ; electrochemistry ; electron paramagnetic resonance spectroscopy ; energy ; ligands ; oxygen ; oxygen production ; pyridines ; spectral analysis
    Language English
    Dates of publication 2021-1102
    Size p. 23802-23816.
    Publishing place The Royal Society of Chemistry
    Document type Article
    ZDB-ID 2702232-8
    ISSN 2050-7496 ; 2050-7488
    ISSN (online) 2050-7496
    ISSN 2050-7488
    DOI 10.1039/d1ta05991b
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  8. Article ; Online: (Li

    Yañez, Osvaldo / Garcia, Victor / Garza, Jorge / Orellana, Walter / Vásquez-Espinal, Alejandro / Tiznado, William

    Chemistry (Weinheim an der Bergstrasse, Germany)

    2019  Volume 25, Issue 10, Page(s) 2467–2471

    Abstract: Extensive explorations of their potential energy surfaces, combined with high-level quantum chemical computations, strikingly show that the lowest energy structures of the ( ... ...

    Abstract Extensive explorations of their potential energy surfaces, combined with high-level quantum chemical computations, strikingly show that the lowest energy structures of the (Li
    Language English
    Publishing date 2019-01-25
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 1478547-x
    ISSN 1521-3765 ; 0947-6539
    ISSN (online) 1521-3765
    ISSN 0947-6539
    DOI 10.1002/chem.201805677
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  9. Article: In search of the most active MN4 catalyst for the oxygen reduction reaction. The case of perfluorinated Fe phthalocyanine

    Abarca, Gabriel / Aliaga, Carolina / Marco, José F / Orellana, Walter / Tasca, Federico / Viera, Marco / Zagal, José H

    Journal of materials chemistry A. 2019 Nov. 5, v. 7, no. 43

    2019  

    Abstract: Iron macrocyclic complexes (MN4) are promising catalysts for replacing platinum (the industrial standard) in electrocatalysis. In particular, FeN4 complexes have shown lower overpotential than Pt for the oxygen reduction reaction (ORR) in alkaline media. ...

    Abstract Iron macrocyclic complexes (MN4) are promising catalysts for replacing platinum (the industrial standard) in electrocatalysis. In particular, FeN4 complexes have shown lower overpotential than Pt for the oxygen reduction reaction (ORR) in alkaline media. To predict the electrochemical activity of metal electrodes and molecular catalysts towards the ORR, reactivity descriptors with typical volcano correlation have been demonstrated. The most important are M–O2 binding energy and M(n)+/M(n−1)+ redox potentials for the complexes. We studied a new Fe complex, which possesses powerful electron-withdrawing fluorine residues at the periphery of the phthalocyanine ring. Fe hexadecafluorophthalocyanine (16(F)FePc) was characterized by electron paramagnetic resonance (EPR), and X-ray photoelectron spectroscopy (XPS) in the presence and in absence of O2. Experimental and calculated O2–Fe binding energies, as well as electrochemical characterization confirms the excellent activity of this complex for the ORR placing this complex at the top of the MN4 volcano correlation.
    Keywords catalysts ; catalytic activity ; electrochemistry ; electrodes ; energy ; fluorine ; iron ; oxygen ; platinum ; redox potential ; X-ray photoelectron spectroscopy
    Language English
    Dates of publication 2019-1105
    Size p. 24776-24783.
    Publishing place The Royal Society of Chemistry
    Document type Article
    ZDB-ID 2702232-8
    ISSN 2050-7496 ; 2050-7488
    ISSN (online) 2050-7496
    ISSN 2050-7488
    DOI 10.1039/c9ta09125d
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  10. Article ; Online: Bowl-shaped Cluster CuB

    Solar-Encinas, José / Leyva-Parra, Luis / Yáñez, Osvaldo / Inostroza, Diego / Barrios-Llacuachaqui, Julio R / Vásquez-Espinal, Alejandro / Orellana, Walter / Tiznado, William

    Chemphyschem : a European journal of chemical physics and physical chemistry

    2022  Volume 23, Issue 19, Page(s) e202200366

    Abstract: A low-lying structure is revealed for the ... ...

    Abstract A low-lying structure is revealed for the CuB
    Language English
    Publishing date 2022-07-19
    Publishing country Germany
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2025223-7
    ISSN 1439-7641 ; 1439-4235
    ISSN (online) 1439-7641
    ISSN 1439-4235
    DOI 10.1002/cphc.202200366
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