1
|
Saavedra E, Tejo F, Vidal-Silva N, Escrig J. Symmetry Breaking-Induced Resonance Dynamics in Bloch Point Nanospheres: Unveiling Magnetic Volume Effects and Geometric Parameters for Advanced Applications in Magnetic Sensing and Spintronics. ACS Appl Mater Interfaces 2024. [PMID: 38754391 DOI: 10.1021/acsami.4c01963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
This study explores the impact of symmetry breaking on the ferromagnetic resonance of Bloch point (BP) nanospheres. Through standard Fourier analysis, we unveil two distinct oscillation mode groups characterized by low and high frequencies, respectively. Our findings emphasize the pivotal role of magnetic volume in shaping resonance amplitudes, providing new insights into the intricate dynamics of BP states. The investigation of geometric parameters reveals a quasi-monotonic decrease in resonance frequencies as a function of the asymmetry degree attributed to symmetry-breaking induced by geometric modifications. Spatial distribution analysis showcases unique resonance frequencies for the upper and lower BP hemispheres, highlighting the nuanced impact of the geometry on mode excitation. As the radius increases, additional modes emerge, demonstrating a compelling relationship between the magnetic volume and frequency. Phase analysis unveils coherent oscillations within each BP hemisphere, offering valuable insights into the rotational directions of the excitation poles. Beyond fundamental understanding, our study opens avenues for innovative applications, suggesting the potential use of nanospheres in advanced magnetic sensing, data storage, and nanoscale spintronic devices.
Collapse
Affiliation(s)
- Eduardo Saavedra
- Departamento de Física, Universidad de Santiago de Chile, Santiago 9170124, Chile
| | - Felipe Tejo
- Escuela de Ingenieria, Universidad Central de Chile, Santiago 8330601, Chile
| | - Nicolas Vidal-Silva
- Departamento de Ciencias Físicas, Universidad de La Frontera, Temuco 4811186, Chile
| | - Juan Escrig
- Departamento de Física, Universidad de Santiago de Chile, Santiago 9170124, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Santiago 9170124, Chile
| |
Collapse
|
2
|
Mélica FN, Saavedra E, Escrig J, Bajales N, Linarez Pérez OE, Arciniegas Jaimes DM. Static and dynamic magnetic properties of circular and square cobalt nanodots in hexagonal cells. Phys Chem Chem Phys 2024; 26:5621-5632. [PMID: 38288508 DOI: 10.1039/d3cp05432b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
In this work we performed a detailed numerical analysis to investigate the static and dynamic magnetic properties of hexagonal cells of square and circular cobalt nanodots as a function of the distance between them and the external magnetic field to which they are subjected. By simulating hysteresis curves with the external magnetic field applied parallel and perpendicular to the plane of these nanostructures, we can conclude that the cobalt nanodots presented a significant perpendicular magnetic anisotropy. We also obtained that the coercivity increases with decreasing volume, which implies that the circular dots have a higher coercivity than the square dots. Furthermore, we studied the dynamic susceptibility of these systems and found that it is possible to control both the position and the number of resonance peaks by controlling the geometry and the distance between the magnetic nanodots. This work provides useful information on the behaviour of cobalt nanodot arrays, opening paths for the design and improvement of two-dimensional technological devices.
Collapse
Affiliation(s)
- Franco N Mélica
- Universidad Nacional de Córdoba (UNC), Facultad de Ciencias Químicas, Departamento de Fisicoquímica, Haya de la Torre esq. Medina Allende, X5000HUA Córdoba, Argentina.
| | - Eduardo Saavedra
- Universidad de Santiago de Chile (USACH), Departamento de Física, Av. Víctor Jara 3493, 9170124 Santiago, Chile
| | - Juan Escrig
- Universidad de Santiago de Chile (USACH), Departamento de Física, Av. Víctor Jara 3493, 9170124 Santiago, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago, Chile
| | - Noelia Bajales
- Universidad Nacional de Córdoba (UNC), FAMAF, 5000 Córdoba, Argentina
- CONICET, IFEG, Av. Medina Allende s/n, 5000 Córdoba, Argentina
| | - Omar E Linarez Pérez
- Universidad Nacional de Córdoba (UNC), Facultad de Ciencias Químicas, Departamento de Fisicoquímica, Haya de la Torre esq. Medina Allende, X5000HUA Córdoba, Argentina.
- CONICET, INFIQC, Haya de la Torre esq. Medina Allende, X5000HUA, Córdoba, Argentina
| | - Diana M Arciniegas Jaimes
- Universidad Nacional de Córdoba (UNC), Facultad de Ciencias Químicas, Departamento de Fisicoquímica, Haya de la Torre esq. Medina Allende, X5000HUA Córdoba, Argentina.
- CONICET, INFIQC, Haya de la Torre esq. Medina Allende, X5000HUA, Córdoba, Argentina
| |
Collapse
|
3
|
Pereira A, Sáez G, Saavedra E, Escrig J. Tunable Magnetic Properties of Interconnected Permalloy Nanowire Networks. Nanomaterials (Basel) 2023; 13:1971. [PMID: 37446487 DOI: 10.3390/nano13131971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/22/2023] [Accepted: 06/25/2023] [Indexed: 07/15/2023]
Abstract
In this study, we investigate the magnetic properties of interconnected permalloy nanowire networks using micromagnetic simulations. The effects of interconnectivity on the hysteresis curves, coercivity, and remanence of the nanowire networks are analyzed. Our results reveal intriguing characteristics of the hysteresis curves, including nonmonotonic behaviors of coercivity as a function of the position of horizontal nanowires relative to vertical nanowires. By introducing horizontal nanowires at specific positions, the coercivity of the nanowire networks can be enhanced without altering the material composition. The normalized remanence remains relatively constant regardless of the position of the horizontal wires, although it is lower in the interconnected nanowire arrays compared to nonconnected arrays. These findings provide valuable insights into the design and optimization of nanowire networks for applications requiring tailored magnetic properties.
Collapse
Affiliation(s)
- Alejandro Pereira
- Department of Sciences, Faculty of Liberal Arts, Adolfo Ibañez University, Santiago 7941169, Chile
| | - Guidobeth Sáez
- Department of Physics, Faculty of Physical and Mathematical Sciences, University of Chile, Santiago 8370448, Chile
| | - Eduardo Saavedra
- Department of Physics, University of Santiago de Chile (USACH), Santiago 9170124, Chile
| | - Juan Escrig
- Department of Physics, University of Santiago de Chile (USACH), Santiago 9170124, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Santiago 9170124, Chile
| |
Collapse
|
4
|
Pusiol EF, Saavedra E, Pereira A, Palma JL, Bajales N, Escrig J. Dynamic susceptibility of Fe 3O 4 nanotubes. Discov Nano 2023; 18:61. [PMID: 37382777 PMCID: PMC10409952 DOI: 10.1186/s11671-023-03841-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Accepted: 03/28/2023] [Indexed: 06/30/2023]
Abstract
In this work we performed a detailed numerical analysis to investigate the dynamic susceptibility of 1000 nm long Fe3O4 nanotubes by varying the diameter, the tube wall thickness and the magnitude of the external magnetic field applied along the tube axis. We found two well-defined modes, one of low frequency associated with the caps of the nanotubes, and another of high frequency associated with the central area of the nanotubes, which can be controlled by varying the geometry of the tubes or the external magnetic field to which they are subjected. These results allow us to suggest the use of these nanotubes in applications that require controlling the resonant frequency in the GHz range.
Collapse
Affiliation(s)
| | - Eduardo Saavedra
- Department of Physics, University of Santiago de Chile (USACH), 9170124, Santiago, Chile
| | - Alejandro Pereira
- Department of Sciences, Faculty of Liberal Arts, Adolfo Ibáñez University, 7941169, Santiago, Chile
| | - Juan Luis Palma
- School of Engineering, Central University of Chile, 8330601, Santiago, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124, Santiago, Chile
| | - Noelia Bajales
- FAMAF, Universidad Nacional de Córdoba, 5000, Córdoba, Argentina
- CONICET, IFEG, Av. Medina Allende s/n, 5000, Córdoba, Argentina
| | - Juan Escrig
- Department of Physics, University of Santiago de Chile (USACH), 9170124, Santiago, Chile.
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124, Santiago, Chile.
| |
Collapse
|
5
|
Olea de la Hoz F, Saavedra E, Pereira A, Escrig J. Static and Dynamic Magnetic Properties of Fe 3O 4 Nanotubes. Nanomaterials (Basel) 2023; 13:1265. [PMID: 37049358 PMCID: PMC10097039 DOI: 10.3390/nano13071265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 03/22/2023] [Accepted: 03/23/2023] [Indexed: 06/19/2023]
Abstract
In this paper, our objective was to investigate the static and dynamic magnetic properties of Fe3O4 nanotubes that are 1000 nm long, by varying the external radius and the thickness of the tube wall. We performed a detailed numerical analysis by simulating hysteresis curves with an external magnetic field applied parallel to the axis of the tubes (along the z-axis). Our findings indicate that nanotubes with an external radius of 30 nm exhibit non-monotonic behavior in their coercivity due to a change in the magnetization reversal mechanism, which was not observed in nanotubes with external radii of 80 nm. Additionally, we explored the dynamic susceptibility of these nanotubes and found that the position and number of resonance peaks can be controlled by manipulating the nanotube geometry. Overall, our study provides valuable insights into the behavior of Fe3O4 nanotubes, which can aid in the design and improvement in pseudo-one-dimensional technological devices.
Collapse
Affiliation(s)
| | - Eduardo Saavedra
- Department of Physics, University of Santiago de Chile (USACH), Santiago 9170124, Chile
| | - Alejandro Pereira
- Department of Sciences, Faculty of Liberal Arts, Adolfo Ibañez University (UAI), Santiago 7941169, Chile
| | - Juan Escrig
- Department of Physics, University of Santiago de Chile (USACH), Santiago 9170124, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Santiago 9170124, Chile
| |
Collapse
|
6
|
Corona RM, Saavedra E, Castillo-Sepulveda S, Escrig J, Altbir D, Carvalho-Santos VL. Curvature-induced stabilization and field-driven dynamics of magnetic hopfions in toroidal nanorings. Nanotechnology 2023; 34:165702. [PMID: 36689765 DOI: 10.1088/1361-6528/acb557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 01/23/2023] [Indexed: 06/17/2023]
Abstract
Three dimensional magnetic textures are a cornerstone in magnetism research. In this work, we analyze the stabilization and dynamic response of a magnetic hopfion hosted in a toroidal nanoring with intrinsic Dzyaloshinskii-Moriya interaction simulating FeGe. Our results evidence that unlike their planar counterparts, where perpendicular magnetic anisotropies are necessary to stabilize hopfions, the shape anisotropy originated on the torus symmetry naturally yields the nucleation of these topological textures. We also analyze the magnetization dynamical response by applying a magnetic field pulse to differentiate among several magnetic patterns. Finally, to understand the nature of spin wave modes, we analyze the spatial distributions of the resonant mode amplitudes and phases and describe the differences among bulk and surface modes. Importantly, hopfions lying in toroidal nanorings present a non-circularly symmetric poloidal resonant mode, which is not observed in other systems hosting hopfions.
Collapse
Affiliation(s)
- R M Corona
- Universidad de Santiago de Chile, Departamento de Física, Avda. Víctor Jara 3493, 9170124 Santiago, Chile
- Center for the Development of Nanoscience and Nanotechnology, CEDENNA, Avda. Libertador Bernardo O'Higgins 3363, 9170124 Santiago, Chile
| | - E Saavedra
- Universidad de Santiago de Chile, Departamento de Física, Avda. Víctor Jara 3493, 9170124 Santiago, Chile
- Center for the Development of Nanoscience and Nanotechnology, CEDENNA, Avda. Libertador Bernardo O'Higgins 3363, 9170124 Santiago, Chile
| | - S Castillo-Sepulveda
- Departamento de Ingeniería, Universidad Autónoma de Chile, Avda. Pedro de Valdivia 425, Providencia, Chile
| | - J Escrig
- Universidad de Santiago de Chile, Departamento de Física, Avda. Víctor Jara 3493, 9170124 Santiago, Chile
- Center for the Development of Nanoscience and Nanotechnology, CEDENNA, Avda. Libertador Bernardo O'Higgins 3363, 9170124 Santiago, Chile
| | - D Altbir
- Universidad de Santiago de Chile, Departamento de Física, Avda. Víctor Jara 3493, 9170124 Santiago, Chile
- Center for the Development of Nanoscience and Nanotechnology, CEDENNA, Avda. Libertador Bernardo O'Higgins 3363, 9170124 Santiago, Chile
| | - V L Carvalho-Santos
- Universidade Federal de Viçosa, Departamento de Física, Avenida Peter Henry Rolfs s/n, 36570-000, Viçosa, MG, Brasil
| |
Collapse
|
7
|
Márquez P, Patiño Vidal C, Pereira A, Vivas L, Palma JL, López de Dicastillo C, Escrig J. Hollow Iron Oxide Nanospheres Obtained through a Combination of Atomic Layer Deposition and Electrospraying Technologies. Nanomaterials (Basel) 2022; 12:3180. [PMID: 36144968 PMCID: PMC9505163 DOI: 10.3390/nano12183180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 09/01/2022] [Accepted: 09/07/2022] [Indexed: 06/16/2023]
Abstract
In the present study, we report on the successful synthesis of hollow iron oxide nanospheres. The hollow Fe3O4 nanospheres were synthesized following a four-step procedure: electrospraying spherical PVP particles, coating these particles with alumina (Al2O3) and hematite (Fe2O3) through atomic layer deposition and, finally, a thermal reduction process to degrade the polymer (PVP) and convert hematite (Fe2O3) into magnetite (Fe3O4). A structural analysis using X-ray diffraction (XRD) confirmed the effectiveness of the thermal reduction process. A morphological analysis confirmed that the four-step procedure allowed for the obtainment of hollow iron oxide nanospheres, even though the reduction process caused a contraction in the diameter of the particles of almost 300 nm, but did not affect the thickness of the walls of the hollow spheres that remained at approximately 15 nm. Magnetic properties of the hollow iron oxide nanospheres enable their use in applications where the agglomeration of magnetic nanostructures in liquid media is commonly not allowed, such as in drug encapsulation and delivery.
Collapse
Affiliation(s)
- Paulina Márquez
- School of Engineering, Central University of Chile, Santiago 8330601, Chile
| | - Cristian Patiño Vidal
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Santiago 9170124, Chile
- Packaging Innovation Center (LABEN), University of Santiago de Chile (USACH), Santiago 9170201, Chile
| | - Alejandro Pereira
- Departament of Sciences, Faculty of Liberal Arts, Adolfo Ibañez University, Santiago 7941169, Chile
| | - Leonardo Vivas
- Department of Physics, University of Santiago de Chile (USACH), Santiago 9170124, Chile
| | - Juan Luis Palma
- School of Engineering, Central University of Chile, Santiago 8330601, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Santiago 9170124, Chile
| | - Carol López de Dicastillo
- Packaging Laboratory, Institute of Agrochemistry and Food Technology (IATA-CSIC), 46980 Paterna, Spain
| | - Juan Escrig
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Santiago 9170124, Chile
- Department of Physics, University of Santiago de Chile (USACH), Santiago 9170124, Chile
| |
Collapse
|
8
|
Navarro E, González MU, Béron F, Tejo F, Escrig J, García-Martín JM. Large-Area Nanopillar Arrays by Glancing Angle Deposition with Tailored Magnetic Properties. Nanomaterials 2022; 12:nano12071186. [PMID: 35407304 PMCID: PMC9000416 DOI: 10.3390/nano12071186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 03/27/2022] [Accepted: 03/28/2022] [Indexed: 02/04/2023]
Abstract
Ferromagnetic films down to thicknesses of tens of nanometers and composed by polycrystalline Fe and Fe2O3 nanopillars are grown in large areas by glancing angle deposition with magnetron sputtering (MS-GLAD). The morphological features of these films strongly depend on the growth conditions. Vertical or tilted nanopillars have been fabricated depending on whether the substrate is kept rotating azimuthally during deposition or not, respectively. The magnetic properties of these nanopillars films, such as hysteresis loops squareness, adjustable switching fields, magnetic anisotropy and coercivity, can be tuned with the specific morphology. In particular, the growth performed through a collimator mask mounted onto a not rotating azimuthally substrate produces almost isolated well-defined tilted nanopillars that exhibit a magnetic hardening. The first-order reversal curves diagrams and micromagnetic simulations revealed that a growth-induced uniaxial anisotropy, associated with an anisotropic surface morphology produced by the glancing angle deposition in the direction perpendicular to the atomic flux, plays an important role in the observed magnetic signatures. These results demonstrate the potential of the MS-GLAD method to fabricate nanostructured films in large area with tailored structural and magnetic properties for technological applications.
Collapse
Affiliation(s)
- Elena Navarro
- Instituto de Magnetismo Aplicado, Universidad Complutense de Madrid-ADIF-CSIC, P.O. Box 155, Las Rozas, 28230 Madrid, Spain
- Departamento de Física de Materiales, Universidad Complutense de Madrid, 28040 Madrid, Spain
- Correspondence:
| | - María Ujué González
- Instituto de Micro y Nanotecnología, IMN-CNM, CSIC (CEI UAM+CSIC), Isaac Newton 8, Tres Cantos, 28760 Madrid, Spain; (M.U.G.); (J.M.G.-M.)
| | - Fanny Béron
- Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas (UNICAMP), Campinas 13083-859, SP, Brazil;
| | - Felipe Tejo
- Departamento de Física, Facultad de Ciencia, Universidad de Santiago de Chile (USACH), Santiago 9170124, Chile; (F.T.); (J.E.)
- Instituto de Ciencia de Materiales de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - Juan Escrig
- Departamento de Física, Facultad de Ciencia, Universidad de Santiago de Chile (USACH), Santiago 9170124, Chile; (F.T.); (J.E.)
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Santiago 9170124, Chile
| | - José Miguel García-Martín
- Instituto de Micro y Nanotecnología, IMN-CNM, CSIC (CEI UAM+CSIC), Isaac Newton 8, Tres Cantos, 28760 Madrid, Spain; (M.U.G.); (J.M.G.-M.)
| |
Collapse
|
9
|
Sáez G, Díaz P, Cisternas E, Vogel EE, Escrig J. Information storage in permalloy modulated magnetic nanowires. Sci Rep 2021; 11:20811. [PMID: 34675243 PMCID: PMC8531287 DOI: 10.1038/s41598-021-00165-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Accepted: 10/01/2021] [Indexed: 11/09/2022] Open
Abstract
A long piece of magnetic material shaped as a central cylindrical wire (diameter [Formula: see text] nm) with two wider coaxial cylindrical portions (diameter [Formula: see text] nm and thickness [Formula: see text] nm) defines a bimodulated nanowire. Micromagnetism is invoked to study the equilibrium energy of the system under the variations of the positions of the modulations along the wire. The system can be thought of as composed of five independent elements (3 segments and 2 modulations) leading to [Formula: see text] possible different magnetic configurations, which will be later simplified to 4. We investigate the stability of the configurations depending on the positions of the modulations. The relative chirality of the modulations has negligible contributions to the energy and they have no effect on the stability of the stored configuration. However, the modulations are extremely important in pinning the domain walls that lead to consider each segment as independent from the rest. A phase diagram reporting the stability of the inscribed magnetic configurations is produced. The stability of the system was then tested under the action of external magnetic fields and it was found that more than 50 mT are necessary to alter the inscribed information. The main purpose of this paper is to find whether a prototype like this can be complemented to be used as a magnetic key or to store information in the form of firmware. Present results indicate that both possibilities are feasible.
Collapse
Affiliation(s)
- Guidobeth Sáez
- Department of Physics, Universidad de La Frontera, Casilla 54-D, Temuco, Chile.
| | - Pablo Díaz
- Department of Physics, Universidad de La Frontera, Casilla 54-D, Temuco, Chile
| | - Eduardo Cisternas
- Department of Physics, Universidad de La Frontera, Casilla 54-D, Temuco, Chile
| | - Eugenio E Vogel
- Department of Physics, Universidad de La Frontera, Casilla 54-D, Temuco, Chile.,Center of Nanoscience and Nanotechnology (CEDENNA), 9170124, Santiago, Chile
| | - Juan Escrig
- Center of Nanoscience and Nanotechnology (CEDENNA), 9170124, Santiago, Chile.,Departamento de Física, Universidad de Santiago de Chile (USACH), Avda. Ecuador 3493, 9170124, Santiago, Chile
| |
Collapse
|
10
|
Carbajo-García MC, Corachán A, Segura M, Monleón J, Escrig J, Faus A, Pellicer A, Cervelló I, Ferrero H. P–543 Inhibition of cell proliferation and extracellular matrix formation in human uterine leiomyomas by 5-aza–2’-deoxycitidine via Wnt/ β-catenin pathway. Hum Reprod 2021. [DOI: 10.1093/humrep/deab130.542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
Study question
Is DNA methylation reversion through DNA methyltransferases (DNMT) inhibitors, such as 5-aza–2’-deoxycitidine, a potential therapeutic option for treatment of patients with uterine leiomyomas (UL)?
Summary answer
5-aza–2’-deoxycitidine reduces proliferation and extracellular matrix (ECM) formation by inhibition of Wnt/ β-catenin pathway on UL cells, suggesting DNMT inhibitors as an option to treat UL. What is known already: UL is a multifactorial disease with an unclear pathogenesis and inaccurate treatment. Aberrant DNA methylation have been found in UL compared to myometrium (MM) tissue, showing hypermethylation of tumor suppressor genes, which contributes to the development of this tumor. The use of DNMT inhibitors, such as 5-aza–2’-deoxycytidine (5-aza-CdR), has been suggested to treat tumors in which altered methylation pattern is related to tumor progression, as occurs in UL. Based on this, we aimed to evaluate whether DNA methylation reversion through 5-aza-CdR reduces cell proliferation and ECM formation in UL cells, being a potential option for UL medical treatment.
Study design, size, duration
Prospective study comparing UL versus MM tissue and human uterine leiomyoma primary (HULP) cells treated with/without 5-aza-CdR at 0 µM (control), 2 µM, 5 µM and 10 µM for 72 hours. UL and MM tissue were collected from women without any hormonal treatment for the last 3 months (n = 16) undergoing myomectomy or hysterectomy due to symptomatic leiomyoma pathology. Participants were recruited between January 2019 and February 2020 at Hospital Universitario y Politecnico La Fe (Spain).
Participants/materials, setting, methods
Samples were collected from Caucasian premenopausal women aged 31–48 years, with a body mass index of < 30 and without hormonal treatment. DNMT1 gene expression was analysed in UL vs MM tissue by qRT-PCR and activity of DNMT was measured in UL and MM tissue and cells by ELISA. 5-aza-CdR effect on proliferation was assessed by CellTiter test and Western blot (WB), apoptosis and ECM analyzed by WB and Wnt/ β-catenin pathway by qRT-PCR and WB. Main results and the role of chance: DNMT1 gene expression was increased in UL compared to MM tissue (fold change [FC]=2.49, p-value [p]=0.0295). Similarly, DNMT activity was increased in both UL compared to MM tissue and HULP cells versus MM cells (6.50 vs 3.76 OD/h/mg, p = 0.026; 211.30 vs 63.67 OD/h/mg, p = 0.284, respectively). After 5-aza-CdR treatment, cell viability of HULP cells was reduced in a dose dependent manner, being statistically significant at 10 µM (85.25%, p = 0.0001). Accordantly, PCNA protein expression was significantly decreased at 10 µM in HULP cells (FC = 0.695, p = 0.034), demonstrating cell proliferation inhibition. Additionally, 5-aza-CdR inhibited ECM protein expression in HULP cells in a dose-dependent manner being statistically significant at 10 µM for COLLAGEN I (FC = 0.654, p = 0.023) and PAI–1 (FC = 0.654, p = 0.023), and at 2 µM and 10 µM for FIBRONECTIN (FC = 0.812, p = 0.020; FC = 0.733, p = 0.035; respectively). Final targets of Wnt/ β-catenin pathway were decreased after 5-aza-CdR treatment, protein expression of WISP1 was significantly inhibited at 10 µM (FC = 0.699, p = 0.026), while expression levels of Wnt/ β-catenin target genes C-MYC (FC = 0.745, p = 0.028 at 2 µM; FC = 0.728, p = 0.019 at 10 µM) and MMP7 (FC = 0.520, p = 0.003 at 5 µM, FC = 0.577, p = 0.007 at 10 µM) were also significantly downregulated in HULP-treated cells vs untreated cells. Limitations, reasons for caution: This study has strict inclusion criteria to diminish epigenetic variability, thereby we should be cautious extrapolating our results to general population. Besides, this is a proof of concept with the inherent cell culture limitations. Further studies are necessary to determine 5-aza-CdR dose and adverse effects on UL in vivo.
Wider implications of the findings: 5-aza-CdR treatment reduces cell proliferation and ECM formation through Wnt/ β-catenin pathway inhibition, suggesting that inhibition of DNA methylation could be a promising new therapeutic approach to treat UL.
Trial registration number
Not applicable
Collapse
Affiliation(s)
- M C Carbajo-García
- Instituto de Investigación Sanitaria La Fe, IVI Foundatoin, Valencia, Spain
- University of Valencia, Department of Pediatrics- Obstetrics and Gynecology, Valencia, Spain
| | - A Corachán
- Instituto de Investigación Sanitaria La Fe, IVI Foundatoin, Valencia, Spain
- University of Valencia, Department of Pediatrics- Obstetrics and Gynecology, Valencia, Spain
| | - M Segura
- Instituto de Investigación Sanitaria La Fe, IVI Foundatoin, Valencia, Spain
- University of Valencia, Department of Pediatrics- Obstetrics and Gynecology, Valencia, Spain
| | - J Monleón
- Hospital Universitario y Politécnico La Fe, Department of Gynecology, Valencia, Spain
| | - J Escrig
- Hospital Universitario y Politécnico La Fe, Department of Gynecology, Valencia, Spain
| | - A Faus
- Instituto de Investigación Sanitaria La Fe, IVI Foundatoin, Valencia, Spain
| | - A Pellicer
- Instituto de Investigación Sanitaria La Fe, IVI Foundatoin, Valencia, Spain
- IVIRMA, Rome, Rome, Italy
| | - I Cervelló
- Instituto de Investigación Sanitaria La Fe, IVI Foundatoin, Valencia, Spain
| | - H Ferrero
- Instituto de Investigación Sanitaria La Fe, IVI Foundatoin, Valencia, Spain
| |
Collapse
|
11
|
Abstract
AbstractIn this work we performed a detailed numerical analysis on the static and dynamic properties of magnetic antidot arrays as a function of their geometry. In particular, we explored how by varying the shape of these antidot arrays from circular holes to stadium-shaped holes, we can effectively control the magnetic properties of the array. Using micromagnetic simulations we evidenced that coercivity is very sensitive to the shape of antidots, while the remanence is more robust to these changes. Furthermore, we studied the dynamic susceptibility of these systems, finding that it is possible to control both the position and the number of resonance peaks simply by changing the geometry of the holes. Thus, this work provides useful insights on the behavior of antidot arrays for different geometries, opening routes for the design and improvement of two-dimensional technologies.
Collapse
|
12
|
Roumiguie M, Brisuda A, Burger M, Escrig J, Hammerer P, Mccracken S, Mostafid H, Muto G, Redorta J, de Reijke T, Shariat S, Ströck V, Malavaud B. Un patient sur quatre ressent un inconfort significatif lors des cystoscopies de surveillance (TVNIM) dans une étude observationnelle européenne. Prog Urol 2020. [DOI: 10.1016/j.purol.2020.07.228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
13
|
Abstract
In this work we study the oscillations of the skyrmion cores in a multilayer nanodot as a function of the number of skyrmions hosted in the system. When all the skyrmions in the nanodot have the same core radius, and after applying a perpendicular spin-polarized current, a relaxation process takes place towards an equilibrium configuration that is accompanied by coherent damped oscillations of the skyrmion cores, whose frequency depends on the number of skyrmions present in the nanodot. Additionally, we found that the oscillation frequency is directly related to the total energy of the system.
Collapse
Affiliation(s)
- Felipe Tejo
- Departamento de Física, Universidad de Santiago de Chile, 9170124, Santiago, Chile. .,Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049, Madrid, Spain.
| | - Felipe Velozo
- Departamento de Física, Universidad de Santiago de Chile, 9170124, Santiago, Chile
| | - Ricardo Gabriel Elías
- Departamento de Física, Universidad de Santiago de Chile, 9170124, Santiago, Chile.,Center for the Development of Nanoscience and Nanotechnology, 9170124, Santiago, Chile
| | - Juan Escrig
- Departamento de Física, Universidad de Santiago de Chile, 9170124, Santiago, Chile.,Center for the Development of Nanoscience and Nanotechnology, 9170124, Santiago, Chile
| |
Collapse
|
14
|
Escrig J, Woolley E, Simeone A, Watson N. Monitoring the cleaning of food fouling in pipes using ultrasonic measurements and machine learning. Food Control 2020. [DOI: 10.1016/j.foodcont.2020.107309] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
|
15
|
Guerrero Correa M, Martínez FB, Vidal CP, Streitt C, Escrig J, de Dicastillo CL. Antimicrobial metal-based nanoparticles: a review on their synthesis, types and antimicrobial action. Beilstein J Nanotechnol 2020; 11:1450-1469. [PMID: 33029474 PMCID: PMC7522459 DOI: 10.3762/bjnano.11.129] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 08/24/2020] [Indexed: 05/26/2023]
Abstract
The investigation of novel nanoparticles with antimicrobial activity has grown in recent years due to the increased incidence of nosocomial infections occurring during hospitalization and food poisoning derived from foodborne pathogens. Antimicrobial agents are necessary in various fields in which biological contamination occurs. For example, in food packaging they are used to control food contamination by microbes, in the medical field the microbial agents are important for reducing the risk of contamination in invasive and routine interventions, and in the textile industry, they can limit the growth of microorganisms due to sweat. The combination of nanotechnology with materials that have an intrinsic antimicrobial activity can result in the development of novel antimicrobial substances. Specifically, metal-based nanoparticles have attracted much interest due to their broad effectiveness against pathogenic microorganisms due to their high surface area and high reactivity. The aim of this review was to explore the state-of-the-art in metal-based nanoparticles, focusing on their synthesis methods, types, and their antimicrobial action. Different techniques used to synthesize metal-based nanoparticles were discussed, including chemical and physical methods and "green synthesis" methods that are free of chemical agents. Although the most studied nanoparticles with antimicrobial properties are metallic or metal-oxide nanoparticles, other types of nanoparticles, such as superparamagnetic iron-oxide nanoparticles and silica-releasing systems also exhibit antimicrobial properties. Finally, since the quantification and understanding of the antimicrobial action of metal-based nanoparticles are key topics, several methods for evaluating in vitro antimicrobial activity and the most common antimicrobial mechanisms (e.g., cell damage and changes in the expression of metabolic genes) were discussed in this review.
Collapse
Affiliation(s)
- Matías Guerrero Correa
- Center of Innovation in Packaging (LABEN), University of Santiago de Chile (USACH), Obispo Umaña 050, 9170201 Santiago, Chile
| | - Fernanda B Martínez
- Center of Innovation in Packaging (LABEN), University of Santiago de Chile (USACH), Obispo Umaña 050, 9170201 Santiago, Chile
| | - Cristian Patiño Vidal
- Center of Innovation in Packaging (LABEN), University of Santiago de Chile (USACH), Obispo Umaña 050, 9170201 Santiago, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago, Chile
| | - Camilo Streitt
- Center of Innovation in Packaging (LABEN), University of Santiago de Chile (USACH), Obispo Umaña 050, 9170201 Santiago, Chile
| | - Juan Escrig
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago, Chile
- Department of Physics, University of Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago, Chile
| | - Carol Lopez de Dicastillo
- Center of Innovation in Packaging (LABEN), University of Santiago de Chile (USACH), Obispo Umaña 050, 9170201 Santiago, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago, Chile
| |
Collapse
|
16
|
Saavedra E, Burr JP, Alburquenque D, Palma JL, García-Martín JM, Escrig J. Co/Ni multilayers ordered according to a periodic, Fibonnacci and Thue Morse sequence obtained by Atomic Layer Deposition. Nano Ex 2020. [DOI: 10.1088/2632-959x/ab9f07] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
Co/Ni multilayers ordered according to a periodic, Fibonnacci and Thue Morse sequence have been obtained by Atomic Layer Deposition and a subsequent process of thermal reduction. The morphology of the multilayers was investigated by scanning electron microscopy, while longitudinal hysteresis curves were obtained by magneto-optical magnetometry of Kerr effect. The morphology of the films varies as a function of their sequence and thickness. Multilayers exhibit coercivities much higher than expected from samples synthesized with other methods. The control of the magnetic properties of multilayers, as a function of their sequence, may allow their use in spintronic devices.
Collapse
|
17
|
Alburquenque D, Márquez P, Troncoso L, Pereira A, Celis F, Sánchez-Arenillas M, Marco J, Gautier J, Escrig J. LiM0.5Mn1.5O4-δ (M = Co or Fe) spinels with a high oxidation state obtained by ultrasound-assisted thermal decomposition of nitrates. Characterization and physicochemical properties. J SOLID STATE CHEM 2020. [DOI: 10.1016/j.jssc.2020.121175] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
18
|
López de Dicastillo C, Patiño Vidal C, Falcó I, Sánchez G, Márquez P, Escrig J. Antimicrobial Bilayer Nanocomposites Based on the Incorporation of As-Synthetized Hollow Zinc Oxide Nanotubes. Nanomaterials (Basel) 2020; 10:nano10030503. [PMID: 32168893 PMCID: PMC7153247 DOI: 10.3390/nano10030503] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 03/04/2020] [Accepted: 03/06/2020] [Indexed: 11/30/2022]
Abstract
An antimicrobial polymeric bilayer structure based on the application of an acrylic coating containing hollow zinc oxide nanotubes over a polymeric substrate was developed in this work. Firstly, zinc oxide nanotubes (ZnONT) were obtained by an atomic layer deposition (ALD) process over electrospun polyvinyl alcohol nanofibers followed by polymer removal through calcination with the purpose of obtaining antimicrobial nanostructures with a high specific area. Parameters of electrospinning, ALD, and calcination processes were set in order to obtain successfully hollow zinc oxide nanotubes. Morphological studies through scanning electron microscopy (SEM) and transmission electron microscopy (TEM) microscopies confirmed the morphological structure of ZnONT with an average diameter of 180 nm and thickness of approximately 60 nm. Thermal and X-ray diffraction (XRD) analyses provided evidence that calcination completely removed the polymer, resulting in a crystalline hexagonal wurtzite structure. Subsequently, ZnONT were incorporated into a polymeric coating over a polyethylene extruded film at two concentrations: 0.5 and 1 wt. % with respect to the polymer weight. An antimicrobial analysis of developed antimicrobial materials was performed following JIS Z2801 against Staphylococcus aureus and Escherichia coli. When compared to active materials containing commercial ZnO nanoparticles, materials containing ZnONT presented higher microbial inhibition principally against Gram-negative bacteria, whose reduction was total for films containing 1 wt. % ZnONT. Antiviral studies were also performed, but these materials did not present significant viral reduction.
Collapse
Affiliation(s)
- Carol López de Dicastillo
- Center of Innovation in Packaging (LABEN), Department of Food Science and Technology, Technology Faculty, University of Santiago de Chile (USACH), Santiago 9170201, Chile;
- CEDENNA (Center for the Development of Nanoscience and Nanotechnology), Santiago 9170124, Chile; (P.M.); (J.E.)
- Correspondence:
| | - Cristian Patiño Vidal
- Center of Innovation in Packaging (LABEN), Department of Food Science and Technology, Technology Faculty, University of Santiago de Chile (USACH), Santiago 9170201, Chile;
- CEDENNA (Center for the Development of Nanoscience and Nanotechnology), Santiago 9170124, Chile; (P.M.); (J.E.)
| | - Irene Falcó
- Department of Preservation and Food Safety Technologies, Institute of Agrochemistry and Food technology (IATA-CSIC), 46980 Paterna, Valencia, Spain; (I.F.); (G.S.)
| | - Gloria Sánchez
- Department of Preservation and Food Safety Technologies, Institute of Agrochemistry and Food technology (IATA-CSIC), 46980 Paterna, Valencia, Spain; (I.F.); (G.S.)
| | - Paulina Márquez
- CEDENNA (Center for the Development of Nanoscience and Nanotechnology), Santiago 9170124, Chile; (P.M.); (J.E.)
- Department of Physics, University of Santiago de Chile (USACH), Santiago 9170124, Chile
| | - Juan Escrig
- CEDENNA (Center for the Development of Nanoscience and Nanotechnology), Santiago 9170124, Chile; (P.M.); (J.E.)
- Department of Physics, University of Santiago de Chile (USACH), Santiago 9170124, Chile
| |
Collapse
|
19
|
Flewett S, Mori TJA, Ovalle A, Oyarzún S, Ibáñez A, Michea S, Escrig J, Denardin J. Soft X-ray magnetic scattering studies of 3D magnetic morphology along buried interfaces in NiFe/CoPd/NiFe nanostructures. Sci Rep 2019; 9:14823. [PMID: 31616007 PMCID: PMC6794309 DOI: 10.1038/s41598-019-51098-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 09/24/2019] [Indexed: 11/29/2022] Open
Abstract
With the continuing interest in new magnetic materials for sensor devices and data storage applications, the community needs reliable and sensitive tools for the characterization of such materials. Soft X-rays tuned to elemental absorption edges are a depth and element sensitive probe of magnetic structure at the nanoscale, and scattering measurements have the potential to provide 3D magnetic structural information of the material. In this work we develop a methodology in transmission geometry that allows one to probe the spatial distribution of the magnetization along the different layers of magnetic heterostructures. We study the in-plane/out-of-plane transition of magnetic domains in multilayer thin film systems consisting of two layers of NiFe top and bottom, and a 50 repeat Co/Pd multilayer in the centre. The experimental data are analysed by simulating scattering data starting from micromagnetic simulations, and we find that the out of plane domains of the Co/Pd multilayer intrude into the NiFe layers to a greater extent than would be expected from micromagnetic simulations performed using the standard magnetically isotropic input parameters for the NiFe layers.
Collapse
Affiliation(s)
- Samuel Flewett
- Instituto de Física, Pontificia Universidad Católica de Valparaíso, Avenida Universidad 330, Valparaíso, Chile.
| | - Thiago J A Mori
- Laboratório Nacional de Luz Síncrotron, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP, 13083-970, Brazil
| | - Alexandra Ovalle
- Instituto de Física, Pontificia Universidad Católica de Valparaíso, Avenida Universidad 330, Valparaíso, Chile
| | - Simón Oyarzún
- Departamento de Física, CEDENNA,, Universidad de Santiago de Chile, USACH, Av. Ecuador, 3493, Santiago, Chile
| | - Antonio Ibáñez
- Departamento de Física, CEDENNA,, Universidad de Santiago de Chile, USACH, Av. Ecuador, 3493, Santiago, Chile
| | - Sebastián Michea
- Instituto de Ciencias Químicas Aplicadas. Facultad de Ingeniería. Universidad Autónoma de Chile. Av. El Llano Subercaseaux, 2801, San Miguel, Chile
| | - Juan Escrig
- Departamento de Física, CEDENNA,, Universidad de Santiago de Chile, USACH, Av. Ecuador, 3493, Santiago, Chile
| | - Juliano Denardin
- Departamento de Física, CEDENNA,, Universidad de Santiago de Chile, USACH, Av. Ecuador, 3493, Santiago, Chile
| |
Collapse
|
20
|
de Dicastillo CL, Patiño C, Galotto MJ, Vásquez-Martínez Y, Torrent C, Alburquenque D, Pereira A, Escrig J. Novel hollow titanium dioxide nanospheres with antimicrobial activity against resistant bacteria. Beilstein J Nanotechnol 2019; 10:1716-1725. [PMID: 31501743 PMCID: PMC6720579 DOI: 10.3762/bjnano.10.167] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 07/30/2019] [Indexed: 05/19/2023]
Abstract
The search for and synthesis of new antimicrobial nanostructures is important to reduce microbial incidence that induces infectious diseases and to aid in the antibiotic resistance crisis, which are two of the most pressing issues in global public health. In this work, novel, hollow, calcined titanium dioxide nanospheres (CSTiO2) were successfully synthesized for the first time through the combination of electrospinning and atomic layer deposition techniques. Poly(vinylpyrrolidone) (PVP) electrosprayed spherical particles were double-coated with alumina and titanium dioxide, and after a calcination process, hollow nanospheres were obtained with a radius of approximately 345 nm and shell thickness of 17 nm. The structural characterization was performed using electron microscopy, and X-ray diffraction and small-angle X-ray diffraction evidenced an anatase titanium dioxide crystalline structure. Thermogravimetric analysis and Fourier-transform infrared spectroscopy studies demonstrated the absence of polymer residue after the calcination process. The antimicrobial properties of the developed CSTiO2 hollow nanospheres were evaluated against different bacteria, including resistant E. coli and S. aureus strains, and when compared to commercial TiO2 nanoparticles, CSTiO2 nanospheres exhibited superior performance. In addition, the positive effect of UV irradiation on the antimicrobial activity was demonstrated.
Collapse
Affiliation(s)
- Carol López de Dicastillo
- Food Packaging Laboratory (Laben-Chile), Department of Science and Food Technology, Faculty of Technology, Universidad de Santiago de Chile (USACH), Obispo Umaña 050, 9170201 Santiago, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago, Chile
| | - Cristian Patiño
- Food Packaging Laboratory (Laben-Chile), Department of Science and Food Technology, Faculty of Technology, Universidad de Santiago de Chile (USACH), Obispo Umaña 050, 9170201 Santiago, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago, Chile
| | - María José Galotto
- Food Packaging Laboratory (Laben-Chile), Department of Science and Food Technology, Faculty of Technology, Universidad de Santiago de Chile (USACH), Obispo Umaña 050, 9170201 Santiago, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago, Chile
| | - Yesseny Vásquez-Martínez
- Program Center for Applied Biomedical Research, School of Medicine, Faculty of Medical Sciences, University of Santiago de Chile, 9170022 Santiago, Chile
- Department of Biology, Faculty of Chemistry and Biology, University of Santiago de Chile, Santiago 9170022, Chile
| | - Claudia Torrent
- Department of Biology, Faculty of Chemistry and Biology, University of Santiago de Chile, Santiago 9170022, Chile
| | - Daniela Alburquenque
- Department of Physics, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago, Chile
| | - Alejandro Pereira
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago, Chile
- Department of Sciences, Faculty of Liberal Arts, University Adolfo Ibáñez, 7941169 Santiago, Chile
| | - Juan Escrig
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago, Chile
- Department of Physics, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago, Chile
| |
Collapse
|
21
|
Palma JL, Pereira A, Álvaro R, García-Martín JM, Escrig J. Magnetic properties of Fe 3O 4 antidot arrays synthesized by AFIR: atomic layer deposition, focused ion beam and thermal reduction. Beilstein J Nanotechnol 2018; 9:1728-1734. [PMID: 29977706 PMCID: PMC6009290 DOI: 10.3762/bjnano.9.164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Accepted: 05/14/2018] [Indexed: 06/08/2023]
Abstract
Magnetic films of magnetite (Fe3O4) with controlled defects, so-called antidot arrays, were synthesized by a new technique called AFIR. AFIR consists of the deposition of a thin film by atomic layer deposition, the generation of square and hexagonal arrays of holes using focused ion beam milling, and the subsequent thermal reduction of the antidot arrays. Magnetic characterizations were carried out by magneto-optic Kerr effect measurements, showing the enhancement of the coercivity for the antidot arrays. AFIR opens a new route to manufacture ordered antidot arrays of magnetic oxides with variable lattice parameters.
Collapse
Affiliation(s)
- Juan L Palma
- Departamento de Ciencias Básicas, Centro de Ingeniería y Desarrollo Sustentable, Facultad de Ingeniería, Universidad Central de Chile, Santa Isabel 1186, 8330601 Santiago, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago, Chile
| | - Alejandro Pereira
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago, Chile
- Departamento de Física, Universidad de Santiago de Chile (USACH), Avda. Ecuador 3493, 9170124 Santiago, Chile
| | - Raquel Álvaro
- Instituto de Micro y Nanotecnología, IMN-CNM, CSIC (CEI UAM+CSIC), Isaac Newton 8, 28760 Tres Cantos, Madrid, Spain
| | - José Miguel García-Martín
- Instituto de Micro y Nanotecnología, IMN-CNM, CSIC (CEI UAM+CSIC), Isaac Newton 8, 28760 Tres Cantos, Madrid, Spain
| | - Juan Escrig
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago, Chile
- Departamento de Física, Universidad de Santiago de Chile (USACH), Avda. Ecuador 3493, 9170124 Santiago, Chile
| |
Collapse
|
22
|
López de Dicastillo C, Patiño C, Galotto MJ, Palma JL, Alburquenque D, Escrig J. Novel Antimicrobial Titanium Dioxide Nanotubes Obtained through a Combination of Atomic Layer Deposition and Electrospinning Technologies. Nanomaterials (Basel) 2018; 8:E128. [PMID: 29495318 PMCID: PMC5853759 DOI: 10.3390/nano8020128] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 02/10/2018] [Accepted: 02/13/2018] [Indexed: 01/23/2023]
Abstract
The search for new antimicrobial substances has increased in recent years. Antimicrobial nanostructures are one of the most promising alternatives. In this work, titanium dioxide nanotubes were obtained by an atomic layer deposition (ALD) process over electrospun polyvinyl alcohol nanofibers (PVN) at different temperatures with the purpose of obtaining antimicrobial nanostructures with a high specific area. Electrospinning and ALD parameters were studied in order to obtain PVN with smallest diameter and highest deposition rate, respectively. Chamber temperature was a key factor during ALD process and an appropriate titanium dioxide deposition performance was achieved at 200 °C. Subsequently, thermal and morphological analysis by SEM and TEM microscopies revealed hollow nanotubes were obtained after calcination process at 600 °C. This temperature allowed complete polymer removal and influenced the resulting anatase crystallographic structure of titanium dioxide that positively affected their antimicrobial activities. X-ray analysis confirmed the change of titanium dioxide crystallographic structure from amorphous phase of deposited PVN to anatase crystalline structure of nanotubes. These new nanostructures with very large surface areas resulted in interesting antimicrobial properties against Gram-positive and Gram-negative bacteria. Titanium dioxide nanotubes presented the highest activity against Escherichia coli with 5 log cycles reduction at 200 μg/mL concentration.
Collapse
Affiliation(s)
- Carol López de Dicastillo
- Food Packaging Laboratory (Laben-Chile), Department of Science and Food Technology, Faculty of Technology, Universidad de Santiago de Chile (USACH), Obispo Umaña 050, 9170201 Santiago, Chile.
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago, Chile.
| | - Cristian Patiño
- Food Packaging Laboratory (Laben-Chile), Department of Science and Food Technology, Faculty of Technology, Universidad de Santiago de Chile (USACH), Obispo Umaña 050, 9170201 Santiago, Chile.
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago, Chile.
| | - María Jose Galotto
- Food Packaging Laboratory (Laben-Chile), Department of Science and Food Technology, Faculty of Technology, Universidad de Santiago de Chile (USACH), Obispo Umaña 050, 9170201 Santiago, Chile.
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago, Chile.
| | - Juan Luis Palma
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago, Chile.
- Department of Basic Sciences, Engineering Faculty, CIDES, Universidad Central de Chile, Santa Isabel 1186, 8330601 Santiago, Chile.
| | - Daniela Alburquenque
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago, Chile.
- Department of Physics, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago, Chile.
| | - Juan Escrig
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), 9170124 Santiago, Chile.
- Department of Physics, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago, Chile.
| |
Collapse
|
23
|
Salem MS, Tejo F, Zierold R, Sergelius P, Moreno JMM, Goerlitz D, Nielsch K, Escrig J. Composition and diameter modulation of magnetic nanowire arrays fabricated by a novel approach. Nanotechnology 2018; 29:065602. [PMID: 29226847 DOI: 10.1088/1361-6528/aaa095] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Straight magnetic nanowires composed of nickel and permalloy segments having different diameters are synthesized using a promising approach. This approach involves the controlled electrodeposition of each magnetic material into specially designed diameter-modulated porous alumina templates. Standard alumina templates are exposed to pore widening followed by a protective coating of the pore wall with ultrathin silica and further anodization. Micromagnetic simulations are employed to investigate the process of magnetization reversal in the fabricated nanowires when the magnetic materials exchange their places in the thick and thin segments. It is found that the magnetization reversal occurs by the propagation of transverse domain wall (DW) when the thick segment is composed of permalloy. However, the reversal process proceeds by the propagation of vortex DW when permalloy is located at the thin segment.
Collapse
|
24
|
Pereira A, Palma JL, Denardin JC, Escrig J. Temperature-dependent magnetic properties of Ni nanotubes synthesized by atomic layer deposition. Nanotechnology 2016; 27:345709. [PMID: 27454022 DOI: 10.1088/0957-4484/27/34/345709] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Highly-ordered and conformal Ni nanotube arrays were prepared by combining atomic layer deposition (ALD) in a porous alumina matrix with a subsequent thermal reduction process. In order to obtain NiO tubes, one ALD NiCp2/O3 cycle was repeated 2000 times. After the ALD process, the sample is reduced from NiO to metallic Ni under hydrogen atmosphere. Their magnetic properties such as coercivity and squareness have been determined in a vibrating sample magnetometer in the temperature range from 5-300 K for applied magnetic fields parallel and perpendicular to the nanotube axis. Ni nanotubes synthesized by ALD provide a promising opportunity for potential applications in spintronics, data storage and bio-applications.
Collapse
Affiliation(s)
- Alejandro Pereira
- Department of Physics, Universidad de Santiago de Chile and Center for the Development of Nanoscience and Nanotechnology, 9170124 Santiago, Chile
| | | | | | | |
Collapse
|
25
|
Espejo AP, Zierold R, Gooth J, Dendooven J, Detavernier C, Escrig J, Nielsch K. Magnetic and electrical characterization of nickel-rich NiFe thin films synthesized by atomic layer deposition and subsequent thermal reduction. Nanotechnology 2016; 27:345707. [PMID: 27454574 DOI: 10.1088/0957-4484/27/34/345707] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Nickel-rich NiFe thin films (Ni92Fe8, Ni89Fe11 and Ni83Fe17) were prepared by combining atomic layer deposition (ALD) with a subsequent thermal reduction process. In order to obtain Ni x Fe1-x O y films, one ALD supercycle was performed according to the following sequence: m NiCp2/O3, with m = 1, 2 or 3, followed by one FeCp2/O3 cycle. The supercycle was repeated n times. The thermal reduction process in hydrogen atmosphere was investigated by in situ x-ray diffraction studies as a function of temperature. The metallic nickel iron alloy thin films were investigated and characterized with respect to crystallinity, morphology, resistivity, and magnetism. As proof-of-concept magnetic properties of an array of Ni83Fe17, close to the perfect Permalloy stoichiometry, nanotubes and an isolated tube were investigated.
Collapse
Affiliation(s)
- A P Espejo
- Departamento de Física, Universidad de Santiago de Chile and Center for the Development of Nanoscience and Nanotechnology, 9170124 Santiago, Chile. Institute of Nanostructure and Solid State Physics, Universität Hamburg, Jungiusstr. 11, D-20335 Hamburg, Germany
| | | | | | | | | | | | | |
Collapse
|
26
|
Pereira A, Palma JL, Vázquez M, Denardin JC, Escrig J. A soft/hard magnetic nanostructure based on multisegmented CoNi nanowires. Phys Chem Chem Phys 2015; 17:5033-8. [PMID: 25597517 DOI: 10.1039/c4cp05665e] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this paper we have introduced a new soft/hard nanostructure based on multisegmented CoNi nanowire arrays having diameters of around 110 nm and made of five segments with nominal compositions of Co, Co66Ni33, Co50Ni50, Co33Ni66 and Ni, each of which has a length of 800 nm, so that the total length of the multisegmented nanowire is 4 μm. These arrays have been synthesized by means of potentiostatic electrodeposition into the pores of hard-anodic alumina templates. The morphology, chemical composition and microstructure of the multisegmented CoNi nanowires were determined by high-resolution scanning electron microscopy, energy dispersive X-ray microanalysis, and powder X-ray diffraction method, respectively. The room temperature magnetic behavior of the multisegmented nanowire arrays is also studied and compared with CoNi nanowire arrays with homogeneous composition (non-segmented nanowires), synthesized in the same templates and having the same dimensions as the segmented ones. These nanostructures could be used to control the movement of magnetic domain walls. In this way, these nanostructures can be an alternative to store information or even perform logic functions.
Collapse
Affiliation(s)
- A Pereira
- Avenida Ecuador 3493, Departamento de Física, Universidad de Santiago de Chile, 9170124 Santiago, Chile.
| | | | | | | | | |
Collapse
|
27
|
Salem MS, Sergelius P, Corona RM, Escrig J, Görlitz D, Nielsch K. Magnetic properties of cylindrical diameter modulated Ni80Fe20 nanowires: interaction and coercive fields. Nanoscale 2013; 5:3941-3947. [PMID: 23535951 DOI: 10.1039/c3nr00633f] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Magnetic properties of cylindrical Ni80Fe20 nanowires with modulated diameters are investigated theoretically as a function of their geometrical parameters and compared with those produced inside the pores of anodic alumina membranes by pulsed electrodeposition. We observe that the Ni80Fe20 nanowires with modulated diameters reverse their magnetization via the nucleation and propagation of a vortex domain wall. The system begins generating vortex domains in the nanowire ends and in the transition region between the two segments to minimize magnetostatic energy generated by surfaces perpendicular to the initial magnetization of the sample. Besides, we observed an increase of the coercivity for the sample with equal volumes in relation to the sample with equal lengths. Finally, the interaction field is stronger in the case of constant volume segments. These structures could be used to control the motions of magnetic domain walls. In this way, these nanowires with modulated diameters can be an alternative to store information or even perform logic functions.
Collapse
|
28
|
Pitzschel K, Bachmann J, Montero-Moreno JM, Escrig J, Görlitz D, Nielsch K. Reversal modes and magnetostatic interactions in Fe3O4/ZrO2/Fe3O4 multilayer nanotubes. Nanotechnology 2012; 23:495718. [PMID: 23164751 DOI: 10.1088/0957-4484/23/49/495718] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Reversal modes and magnetostatic interactions of multilayered Fe(3)O(4)/ZrO(2)/Fe(3)O(4) nanotubes consisting of a ferromagnetic internal tube, an intermediate non-magnetic spacer and an external magnetic shell are investigated as a function of their geometric parameters and compared with those produced inside the pores of anodic alumina membranes by atomic layer deposition. Based on a continuum approach we obtained analytical expressions that underline the first experimental results and support their interpretation that the system of multilayer tubes behaves as the reversal of two isolated systems. It is observed that the magnetostatic interaction between both phases depends on the magnetic configurations in each phase and also on the geometrical parameters considered. These structures have potential applications in novel spintronics devices, ultra-small magnetic media and other nano-devices.
Collapse
|
29
|
Priego P, Rivadulla I, Daroca J, Escrig J, Salvador Sanchís JL. [Laparoscopic resection of heterotopic pancreatic tissue in the gastric antrum]. Rev Esp Enferm Dig 2010; 101:732-3. [PMID: 19899943 DOI: 10.4321/s1130-01082009001000011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
30
|
Pitzschel K, Moreno JMM, Escrig J, Albrecht O, Nielsch K, Bachmann J. Controlled introduction of diameter modulations in arrayed magnetic iron oxide nanotubes. ACS Nano 2009; 3:3463-8. [PMID: 19803498 DOI: 10.1021/nn900909q] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
To date, no large-scale preparative method for arrays of nanotube enables the experimentalist to arbitrarily define changes in the tubes' diameter along their length. To this goal, we start with anodic alumina substrates displaying controlled modulations in pore diameter obtained by alternating "mild" and "hard" electrochemical etching conditions. We then utilize atomic layer deposition (ALD) to coat the internal pore walls with conformal layers of an oxide. Ferromagnetic Fe(3)O(4) tubes of 10 nm wall thickness and 10-30 microm in length are thus prepared, which replicate the modulated silhouette of the template. Their magnetic properties strongly depend on the presence of diameter modulations. Introducing one or several very short segments of large diameter (150 nm) into an otherwise thin tube (70 nm diameter) brings its initially large coercive field down to a value close to the case of a homogeneously thick tube. Theoretical modeling emphasizes the major influence of the magnetostatic interactions between neighboring tubes. They are enhanced locally at the sites of diameter modulations, which directly translates into a reduction in coercive field.
Collapse
|
31
|
Abstract
The hysteresis of multilayer nanowires composed by a soft magnetic cylindrical wire, a non-magnetic spacer layer and an external hard magnetic shell is investigated. The external magnetic shell originates a non-homogeneous magnetic field on the inner wire, which is responsible for a displacement and a change of the width of the hysteresis curve of the wire. Moreover, different reversal modes occur at each branch of the hysteresis loop, which can be understood by analyzing the interaction magnetostatic field along the wire. Our results open the possibility of controlling two parameters of the hysteresis loop, the coercivity and the bias, providing an interesting system to be investigated.
Collapse
Affiliation(s)
- S Allende
- Departamento de Física, Universidad de Santiago de Chile (USACH), Avenida Ecuador 3493, 917-0124 Santiago, Chile
| | | | | | | | | |
Collapse
|
32
|
Abstract
The magnetic configurations of barcode-type magnetic nanostructures consisting of alternate ferromagnetic and nonmagnetic layers arranged within a multilayer nanotube structure are investigated as a function of their geometry. Based on a continuum approach we have obtained analytical expressions for the energy which lead us to obtain phase diagrams giving the relative stability of characteristic internal magnetic configurations of the barcode-type nanostructures.
Collapse
Affiliation(s)
- B Leighton
- Departamento de Física, Universidad de Santiago de Chile, Avenida Ecuador 3493, 917-0124 Santiago, Chile
| | | | | | | |
Collapse
|
33
|
Escrig J, Lavín R, Palma JL, Denardin JC, Altbir D, Cortés A, Gómez H. Geometry dependence of coercivity in Ni nanowire arrays. Nanotechnology 2008; 19:075713. [PMID: 21817661 DOI: 10.1088/0957-4484/19/7/075713] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Magnetic properties of arrays of nanowires produced inside the pores of anodic alumina membranes have been studied by means of vibrating sample magnetometer techniques. In these systems the length of the wires strongly influences the coercivity of the array. A simple model for the coercivity as a function of the geometry is presented which exhibits good agreement with experimental results. Magnetostatic interactions between the wires are responsible for a decrease of the coercive field.
Collapse
Affiliation(s)
- J Escrig
- Departamento de Física, Universidad de Santiago de Chile, USACH, Avenida Ecuador 3493, 917-0124 Santiago, Chile
| | | | | | | | | | | | | |
Collapse
|
34
|
Boldó E, Perez de Lucia G, Aracil JP, Martin F, Escrig J, Martinez D, Miralles JM, Armelles A. Trocar site hernia after laparoscopic ventral hernia repair. Surg Endosc 2006; 21:798-800. [PMID: 17177087 DOI: 10.1007/s00464-006-9015-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Revised: 05/10/2006] [Accepted: 06/11/2006] [Indexed: 11/26/2022]
Abstract
BACKGROUND The incidence of trocar site hernia (TSH) after laparoscopic ventral hernia repair (LVHR) is reported to be low. The present study investigates the associated risk factors, with a view to preventing this complication. METHODS A retrospective study was made of the incidence of TSH in a personal series of LVHR, recording anthropometric and clinical data on the patients. Risk factors were assessed by bivariate and multivariate analyses. The patients were subjected to clinical and telephone follow-up. RESULTS In a series of 27 LVHR, the incidence of TSH was 22% (6 patients). The use of meshes larger than 10 x 15 cm for LVHR was the only TSH risk factor to reach statistical significance. Female gender and diabetes showed a higher incidence in the TSH group. CONCLUSIONS The use of large meshes may be a risk factor for TSH. We believe this to be due to dilatation of the trocar orifice during introduction of the mesh, and also to postoperative retraction of the mesh.
Collapse
Affiliation(s)
- E Boldó
- Consorcio Hospitalario Provincial de Castellon, Avenida Ferrandis Salvador 50, 12100, Castellon, Spain.
| | | | | | | | | | | | | | | |
Collapse
|
35
|
Gamón R, Escrig J, Salvador J, Marcote E, Lara A, De Lera J. El rendimiento diagnóstico del 99mTc-sestamibi cambia según la localización y el tipo de hiperparatiroidismo. Análisis multivariante. Cir Esp 2002. [DOI: 10.1016/s0009-739x(02)71945-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
36
|
Asencio F, Aguiló J, Salvador JL, Villar A, De la Morena E, Ahamad M, Escrig J, Puche J, Viciano V, Sanmiguel G, Ruiz J. Video-laparoscopic staging of gastric cancer. A prospective multicenter comparison with noninvasive techniques. Surg Endosc 1997; 11:1153-8. [PMID: 9373284 DOI: 10.1007/s004649900559] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND The high proportion of gastric carcinomas present in an unresectable stage, together with the emergence of multimodal treatments, increases the usefulness of objective staging methods that avoid unnecessary laparotomies. METHODS A prospective evaluation of the accuracy of laparoscopy in the staging of 71 patients with gastric adenocarcinoma is presented. Serosal infiltration, retroperitoneal fixation, metastasis to lymph nodes, peritoneal and liver metastasis, and ascites were determined in the staging workup. Sensitivity, specificity, and predictive values were calculated and compared with those obtained with ultrasonography (US) and computed tomography (CT). RESULTS The diagnostic accuracy of laparoscopy in the determination of resectability was 98.6%. Consequently, over 40% of patients were spared unnecessary laparotomies. Laparoscopy yielded diagnostic indices superior to US and CT for all the tumoral attributes studied. Our technique permits accurate assessment and pathologic verification of liver and the peritoneal and retroperitoneal extent of tumor invasion in the majority of patients. CONCLUSIONS Laparoscopy in gastric adenocarcinoma is a reliable technique that provides accurate assessment of resectability and stage, thus avoiding unnecessary laparotomies in patients in whom surgical palliation is not indicated. A stepwise diagnostic workup combining imaging and minimally invasive techniques is proposed.
Collapse
Affiliation(s)
- F Asencio
- Hospital Arnau de Vilanova, Valencia, Spain
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|