1
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Adambukulam C, Johnson BC, Morello A, Laucht A. Hyperfine Spectroscopy and Fast, All-Optical Arbitrary State Initialization and Readout of a Single, Ten-Level ^{73}Ge Vacancy Nuclear Spin Qudit in Diamond. Phys Rev Lett 2024; 132:060603. [PMID: 38394595 DOI: 10.1103/physrevlett.132.060603] [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] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 01/11/2024] [Indexed: 02/25/2024]
Abstract
A high-spin nucleus coupled to a color center can act as a long-lived memory qudit in a spin-photon interface. The germanium vacancy (GeV) in diamond has attracted recent attention due to its excellent spectral properties and provides access to the ten-dimensional Hilbert space of the I=9/2 ^{73}Ge nucleus. Here, we observe the ^{73}GeV hyperfine structure, perform nuclear spin readout, and optically initialize the ^{73}Ge spin into any eigenstate on a μs timescale and with a fidelity of up to ∼84%. Our results establish ^{73}GeV as an optically addressable high-spin quantum platform for a high-efficiency spin-photon interface as well as for foundational quantum physics and metrology.
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Affiliation(s)
- C Adambukulam
- School of Electrical Engineering and Telecommunications, University of New South Wales, Kensington, NSW 2052, Australia
| | - B C Johnson
- School of Science, RMIT University, Melbourne, VIC 3001, Australia
| | - A Morello
- School of Electrical Engineering and Telecommunications, University of New South Wales, Kensington, NSW 2052, Australia
| | - A Laucht
- School of Electrical Engineering and Telecommunications, University of New South Wales, Kensington, NSW 2052, Australia
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2
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Adambukulam C, Sewani VK, Stemp HG, Asaad S, Mądzik MT, Morello A, Laucht A. An ultra-stable 1.5 T permanent magnet assembly for qubit experiments at cryogenic temperatures. Rev Sci Instrum 2021; 92:085106. [PMID: 34470423 DOI: 10.1063/5.0055318] [Citation(s) in RCA: 1] [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] [Received: 04/27/2021] [Accepted: 07/14/2021] [Indexed: 06/13/2023]
Abstract
Magnetic fields are a standard tool in the toolbox of every physicist and are required for the characterization of materials, as well as the polarization of spins in nuclear magnetic resonance or electron paramagnetic resonance experiments. Quite often, a static magnetic field of sufficiently large, but fixed, magnitude is suitable for these tasks. Here, we present a permanent magnet assembly that can achieve magnetic field strengths of up to 1.5 T over an air gap length of 7 mm. The assembly is based on a Halbach array of neodymium magnets, with the inclusion of the soft magnetic material Supermendur to boost the magnetic field strength inside the air gap. We present the design, simulation, and characterization of the permanent magnet assembly, measuring an outstanding magnetic field stability with a drift rate of |D| < 2.8 ppb/h. Our measurements demonstrate that this assembly can be used for spin qubit experiments inside a dilution refrigerator, successfully replacing the more expensive and bulky superconducting solenoids.
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Affiliation(s)
- C Adambukulam
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, New South Wales 2052, Australia
| | - V K Sewani
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, New South Wales 2052, Australia
| | - H G Stemp
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, New South Wales 2052, Australia
| | - S Asaad
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, New South Wales 2052, Australia
| | - M T Mądzik
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, New South Wales 2052, Australia
| | - A Morello
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, New South Wales 2052, Australia
| | - A Laucht
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, New South Wales 2052, Australia
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3
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Yoneda J, Huang W, Feng M, Yang CH, Chan KW, Tanttu T, Gilbert W, Leon RCC, Hudson FE, Itoh KM, Morello A, Bartlett SD, Laucht A, Saraiva A, Dzurak AS. Coherent spin qubit transport in silicon. Nat Commun 2021; 12:4114. [PMID: 34226564 PMCID: PMC8257656 DOI: 10.1038/s41467-021-24371-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [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: 11/05/2020] [Accepted: 05/23/2021] [Indexed: 11/09/2022] Open
Abstract
A fault-tolerant quantum processor may be configured using stationary qubits interacting only with their nearest neighbours, but at the cost of significant overheads in physical qubits per logical qubit. Such overheads could be reduced by coherently transporting qubits across the chip, allowing connectivity beyond immediate neighbours. Here we demonstrate high-fidelity coherent transport of an electron spin qubit between quantum dots in isotopically-enriched silicon. We observe qubit precession in the inter-site tunnelling regime and assess the impact of qubit transport using Ramsey interferometry and quantum state tomography techniques. We report a polarization transfer fidelity of 99.97% and an average coherent transfer fidelity of 99.4%. Our results provide key elements for high-fidelity, on-chip quantum information distribution, as long envisaged, reinforcing the scaling prospects of silicon-based spin qubits.
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Affiliation(s)
- J Yoneda
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, Australia. .,Tokyo Tech Academy for Super Smart Society, Tokyo Institute of Technology, Tokyo, Japan.
| | - W Huang
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, Australia.,Solid State Physics Laboratory, ETH Zurich, Zurich, Switzerland
| | - M Feng
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, Australia
| | - C H Yang
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, Australia
| | - K W Chan
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, Australia
| | - T Tanttu
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, Australia
| | - W Gilbert
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, Australia
| | - R C C Leon
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, Australia
| | - F E Hudson
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, Australia
| | - K M Itoh
- School of Fundamental Science and Technology, Keio University, Yokohama, Japan
| | - A Morello
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, Australia
| | - S D Bartlett
- Centre for Engineered Quantum Systems, School of Physics, University of Sydney, Sydney, NSW, Australia
| | - A Laucht
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, Australia
| | - A Saraiva
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, Australia
| | - A S Dzurak
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, Australia.
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4
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Leon RCC, Yang CH, Hwang JCC, Lemyre JC, Tanttu T, Huang W, Chan KW, Tan KY, Hudson FE, Itoh KM, Morello A, Laucht A, Pioro-Ladrière M, Saraiva A, Dzurak AS. Coherent spin control of s-, p-, d- and f-electrons in a silicon quantum dot. Nat Commun 2020; 11:797. [PMID: 32047151 PMCID: PMC7012832 DOI: 10.1038/s41467-019-14053-w] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 12/11/2019] [Indexed: 11/09/2022] Open
Abstract
Once the periodic properties of elements were unveiled, chemical behaviour could be understood in terms of the valence of atoms. Ideally, this rationale would extend to quantum dots, and quantum computation could be performed by merely controlling the outer-shell electrons of dot-based qubits. Imperfections in semiconductor materials disrupt this analogy, so real devices seldom display a systematic many-electron arrangement. We demonstrate here an electrostatically confined quantum dot that reveals a well defined shell structure. We observe four shells (31 electrons) with multiplicities given by spin and valley degrees of freedom. Various fillings containing a single valence electron-namely 1, 5, 13 and 25 electrons-are found to be potential qubits. An integrated micromagnet allows us to perform electrically-driven spin resonance (EDSR), leading to faster Rabi rotations and higher fidelity single qubit gates at higher shell states. We investigate the impact of orbital excitations on single qubits as a function of the dot deformation and exploit it for faster qubit control.
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Affiliation(s)
- R C C Leon
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia.
| | - C H Yang
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - J C C Hwang
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
- Research and Prototype Foundry, The University of Sydney, Sydney, NSW, 2006, Australia
| | - J Camirand Lemyre
- Institut Quantique et Département de Physique, Université de Sherbrooke, Sherbrooke, Québec, J1K 2R1, Canada
| | - T Tanttu
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - W Huang
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - K W Chan
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - K Y Tan
- QCD Labs COMP Centre of Excellence, Department of Applied Physics, Aalto University, 00076, Aalto, Finland
| | - F E Hudson
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - K M Itoh
- School of Fundamental Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohokuku, Yokohama, 223-8522, Japan
| | - A Morello
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - A Laucht
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - M Pioro-Ladrière
- Institut Quantique et Département de Physique, Université de Sherbrooke, Sherbrooke, Québec, J1K 2R1, Canada
- Quantum Information Science Program, Canadian Institute for Advanced Research, Toronto, ON, M5G 1Z8, Canada
| | - A Saraiva
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia.
| | - A S Dzurak
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia.
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5
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Zhao R, Tanttu T, Tan KY, Hensen B, Chan KW, Hwang JCC, Leon RCC, Yang CH, Gilbert W, Hudson FE, Itoh KM, Kiselev AA, Ladd TD, Morello A, Laucht A, Dzurak AS. Single-spin qubits in isotopically enriched silicon at low magnetic field. Nat Commun 2019; 10:5500. [PMID: 31796728 PMCID: PMC6890755 DOI: 10.1038/s41467-019-13416-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 11/06/2019] [Indexed: 11/09/2022] Open
Abstract
Single-electron spin qubits employ magnetic fields on the order of 1 Tesla or above to enable quantum state readout via spin-dependent-tunnelling. This requires demanding microwave engineering for coherent spin resonance control, which limits the prospects for large scale multi-qubit systems. Alternatively, singlet-triplet readout enables high-fidelity spin-state measurements in much lower magnetic fields, without the need for reservoirs. Here, we demonstrate low-field operation of metal-oxide-silicon quantum dot qubits by combining coherent single-spin control with high-fidelity, single-shot, Pauli-spin-blockade-based ST readout. We discover that the qubits decohere faster at low magnetic fields with [Formula: see text] μs and [Formula: see text] μs at 150 mT. Their coherence is limited by spin flips of residual 29Si nuclei in the isotopically enriched 28Si host material, which occur more frequently at lower fields. Our finding indicates that new trade-offs will be required to ensure the frequency stabilization of spin qubits, and highlights the importance of isotopic enrichment of device substrates for the realization of a scalable silicon-based quantum processor.
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Affiliation(s)
- R Zhao
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia.
- National Institute of Standards and Technology, 325 Broadway, Boulder, CO, 80305, USA.
| | - T Tanttu
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia
| | - K Y Tan
- QCD Labs, QTF Centre of Excellence, Department of Applied Physics, Aalto University, 00076, Aalto, Finland
- IQM Finland Oy, Vaisalantie 6 C, 02130, Espoo, Finland
| | - B Hensen
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia
| | - K W Chan
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia
| | - J C C Hwang
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia
- Research and Prototype Foundry, The University of Sydney, Sydney, NSW, 2006, Australia
| | - R C C Leon
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia
| | - C H Yang
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia
| | - W Gilbert
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia
| | - F E Hudson
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia
| | - K M Itoh
- School of Fundamental Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, 223-8522, Japan
| | - A A Kiselev
- HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA, 90265, USA
| | - T D Ladd
- HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA, 90265, USA
| | - A Morello
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia
| | - A Laucht
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia
| | - A S Dzurak
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia.
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6
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Minehart J, Eguchi T, Morello A, Adusumilli P. OA14.03 Clinical Rationale and Preclinical Evidence for Chimeric Antigen Receptor (CAR) T Cell Therapy Clinical Trial in KRAS-Mutant Lung Cancer. J Thorac Oncol 2019. [DOI: 10.1016/j.jtho.2019.08.485] [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: 11/30/2022]
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7
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Monsellato I, Morello A, Argenio G, Canepa MC, Lenti LM, Priora F. Spontaneous bladder rupture mimicking a jejuno-ileal perforation. G Chir 2018; 34:315-318. [PMID: 30444481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Spontaneous urinary bladder perforation is a very rare disease. The main cause of urinary perforation, indeed, is a damage to the urinary bladder wall by blunt or penetrating trauma. There are only few idiopathic spontaneous rupture of urinary bladder (ISRUB) cases reported in the literature. Pre-operative diagnosis is very difficult due to similar symptoms, laboratory and imaging findings of a gastrointestinal perforation that is usually excluded intraoperatively. Herein we report a case of a 91-year-old man presented to the emergency department with a spontaneous bladder perforation mimicking an ileal perforation.
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8
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Lamberti M, Gagliano A, Italiano D, Morello A, Guerriero L, D’Amico G, Germanò E, Calabrò M, Persico A, Spina E. EKG Parameters in Children and Adolescents Treated with Second-Generation Antipsychotics: A 24-Months Prospective Follow-Up Study. Clin Ther 2017. [DOI: 10.1016/j.clinthera.2017.05.135] [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: 11/16/2022]
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9
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Laucht A, Kalra R, Simmons S, Dehollain JP, Muhonen JT, Mohiyaddin FA, Freer S, Hudson FE, Itoh KM, Jamieson DN, McCallum JC, Dzurak AS, Morello A. A dressed spin qubit in silicon. Nat Nanotechnol 2017; 12:61-66. [PMID: 27749833 DOI: 10.1038/nnano.2016.178] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Accepted: 08/17/2016] [Indexed: 06/06/2023]
Abstract
Coherent dressing of a quantum two-level system provides access to a new quantum system with improved properties-a different and easily tunable level splitting, faster control and longer coherence times. In our work we investigate the properties of the dressed, donor-bound electron spin in silicon, and assess its potential as a quantum bit in scalable architectures. The two dressed spin-polariton levels constitute a quantum bit that can be coherently driven with an oscillating magnetic field, an oscillating electric field, frequency modulation of the driving field or a simple detuning pulse. We measure coherence times of and , one order of magnitude longer than those of the undressed spin. Furthermore, the use of the dressed states enables coherent coupling of the solid-state spins to electric fields and mechanical oscillations.
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Affiliation(s)
- Arne Laucht
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Australia, Sydney, New South Wales 2052, Australia
| | - Rachpon Kalra
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Australia, Sydney, New South Wales 2052, Australia
| | - Stephanie Simmons
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Australia, Sydney, New South Wales 2052, Australia
| | - Juan P Dehollain
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Australia, Sydney, New South Wales 2052, Australia
| | - Juha T Muhonen
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Australia, Sydney, New South Wales 2052, Australia
| | - Fahd A Mohiyaddin
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Australia, Sydney, New South Wales 2052, Australia
| | - Solomon Freer
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Australia, Sydney, New South Wales 2052, Australia
| | - Fay E Hudson
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Australia, Sydney, New South Wales 2052, Australia
| | - Kohei M Itoh
- School of Fundamental Science and Technology, Keio University, 3-14-1 Hiyoshi, Kanagawa 223-8522, Japan
| | - David N Jamieson
- Centre for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Jeffrey C McCallum
- Centre for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Andrew S Dzurak
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Australia, Sydney, New South Wales 2052, Australia
| | - A Morello
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Australia, Sydney, New South Wales 2052, Australia
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10
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Seguel V, Castro L, Reigada C, Cortes L, Díaz MV, Miranda MR, Pereira CA, Lapier M, Campos-Estrada C, Morello A, Kemmerling U, Maya JD, López-Muñoz R. Pentamidine antagonizes the benznidazole's effect in vitro, and lacks of synergy in vivo: Implications about the polyamine transport as an anti-Trypanosoma cruzi target. Exp Parasitol 2016; 171:23-32. [DOI: 10.1016/j.exppara.2016.10.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 09/02/2016] [Accepted: 10/06/2016] [Indexed: 12/19/2022]
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11
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van Donkelaar J, Yang C, Alves ADC, McCallum JC, Hougaard C, Johnson BC, Hudson FE, Dzurak AS, Morello A, Spemann D, Jamieson DN. Single atom devices by ion implantation. J Phys Condens Matter 2015; 27:154204. [PMID: 25783169 DOI: 10.1088/0953-8984/27/15/154204] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
To expand the capabilities of semiconductor devices for new functions exploiting the quantum states of single donors or other impurity atoms requires a deterministic fabrication method. Ion implantation is a standard tool of the semiconductor industry and we have developed pathways to deterministic ion implantation to address this challenge. Although ion straggling limits the precision with which atoms can be positioned, for single atom devices it is possible to use post-implantation techniques to locate favourably placed atoms in devices for control and readout. However, large-scale devices will require improved precision. We examine here how the method of ion beam induced charge, already demonstrated for the deterministic ion implantation of 14 keV P donor atoms in silicon, can be used to implant a non-Poisson distribution of ions in silicon. Further, we demonstrate the method can be developed to higher precision by the incorporation of new deterministic ion implantation strategies that employ on-chip detectors with internal charge gain. In a silicon device we show a pulse height spectrum for 14 keV P ion impact that shows an internal gain of 3 that has the potential of allowing deterministic implantation of sub-14 keV P ions with reduced straggling.
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Affiliation(s)
- Jessica van Donkelaar
- Centre for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Melbourne, Victoria 3010, Australia
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12
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Muhonen JT, Laucht A, Simmons S, Dehollain JP, Kalra R, Hudson FE, Freer S, Itoh KM, Jamieson DN, McCallum JC, Dzurak AS, Morello A. Quantifying the quantum gate fidelity of single-atom spin qubits in silicon by randomized benchmarking. J Phys Condens Matter 2015; 27:154205. [PMID: 25783435 DOI: 10.1088/0953-8984/27/15/154205] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Building upon the demonstration of coherent control and single-shot readout of the electron and nuclear spins of individual (31)P atoms in silicon, we present here a systematic experimental estimate of quantum gate fidelities using randomized benchmarking of 1-qubit gates in the Clifford group. We apply this analysis to the electron and the ionized (31)P nucleus of a single P donor in isotopically purified (28)Si. We find average gate fidelities of 99.95% for the electron and 99.99% for the nuclear spin. These values are above certain error correction thresholds and demonstrate the potential of donor-based quantum computing in silicon. By studying the influence of the shape and power of the control pulses, we find evidence that the present limitation to the gate fidelity is mostly related to the external hardware and not the intrinsic behaviour of the qubit.
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Affiliation(s)
- J T Muhonen
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Australia, Sydney, NSW 2052, Australia
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13
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Veldhorst M, Hwang JCC, Yang CH, Leenstra AW, de Ronde B, Dehollain JP, Muhonen JT, Hudson FE, Itoh KM, Morello A, Dzurak AS. An addressable quantum dot qubit with fault-tolerant control-fidelity. Nat Nanotechnol 2014; 9:981-985. [PMID: 25305743 DOI: 10.1038/nnano.2014.216] [Citation(s) in RCA: 199] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 08/28/2014] [Indexed: 06/04/2023]
Abstract
Exciting progress towards spin-based quantum computing has recently been made with qubits realized using nitrogen-vacancy centres in diamond and phosphorus atoms in silicon. For example, long coherence times were made possible by the presence of spin-free isotopes of carbon and silicon. However, despite promising single-atom nanotechnologies, there remain substantial challenges in coupling such qubits and addressing them individually. Conversely, lithographically defined quantum dots have an exchange coupling that can be precisely engineered, but strong coupling to noise has severely limited their dephasing times and control fidelities. Here, we combine the best aspects of both spin qubit schemes and demonstrate a gate-addressable quantum dot qubit in isotopically engineered silicon with a control fidelity of 99.6%, obtained via Clifford-based randomized benchmarking and consistent with that required for fault-tolerant quantum computing. This qubit has dephasing time T2* = 120 μs and coherence time T2 = 28 ms, both orders of magnitude larger than in other types of semiconductor qubit. By gate-voltage-tuning the electron g*-factor we can Stark shift the electron spin resonance frequency by more than 3,000 times the 2.4 kHz electron spin resonance linewidth, providing a direct route to large-scale arrays of addressable high-fidelity qubits that are compatible with existing manufacturing technologies.
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Affiliation(s)
- M Veldhorst
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - J C C Hwang
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - C H Yang
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - A W Leenstra
- University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - B de Ronde
- University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - J P Dehollain
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - J T Muhonen
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - F E Hudson
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - K M Itoh
- School of Fundamental Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
| | - A Morello
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - A S Dzurak
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
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Muñoz OM, Maya JD, Ferreira J, Christen P, Martin JS, López-Muñoz R, Morello A, Kemmerling U. Medicinal Plants of Chile: Evaluation of their Anti-Trypanosoma cruzi Activity. ACTA ACUST UNITED AC 2014. [DOI: 10.1515/znc-2013-5-605] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [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]
Abstract
The extracts of several plants of Central Chile exhibited anti-Trypanosoma cruzi trypomastigotes activity. Most active extracts were those obtained from Podanthus ovatifolius, Berberis microphylla, Kageneckia oblonga, and Drimys winteri. The active extract of Drimys winteri (IC50 51.2 μg/mL) was purifi ed and three drimane sesquiterpenes were obtained: polygodial, drimenol, and isodrimenin. Isodrimenin and drimenol were found to be active against the trypomastigote form of T. cruzi with IC50 values of 27.9 and 25.1 μM, respectively.
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Affiliation(s)
- Orlando M. Muñoz
- Department of Chemistry, Faculty of Science, University of Chile, Santiago, Chile. Fax: 56-2 2713888
| | - Juan D. Maya
- Institute of Biological Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Jorge Ferreira
- Institute of Biological Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Philippe Christen
- School of Pharmaceutical Sciences, EPGL, University of Geneva, University of Lausanne, 30, Quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | - José San Martin
- Instituto de Biología Vegetal y Biotecnología, Universidad de Talca, Talca, Chile
| | - Rodrigo López-Muñoz
- Institute of Biological Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Antonio Morello
- Institute of Biological Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Ulrike Kemmerling
- Institute of Biological Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
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15
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Morello A, Millán A, de Jongh LJ. Observation of zero-point quantum fluctuations of a single-molecule magnet through the relaxation of its nuclear spin bath. Phys Rev Lett 2014; 112:117202. [PMID: 24702408 DOI: 10.1103/physrevlett.112.117202] [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] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Indexed: 06/03/2023]
Abstract
A single-molecule magnet placed in a magnetic field perpendicular to its anisotropy axis can be truncated to an effective two-level system, with easily tunable energy splitting. The quantum coherence of the molecular spin is largely determined by the dynamics of the surrounding nuclear spin bath. Here we report the measurement of the nuclear spin-lattice relaxation rate 1/T1n in a single crystal of the single-molecule magnet Mn12-ac, at T ≈ 30 mK in perpendicular fields B⊥ up to 9 T. The relaxation channel at B ≈ 0 is dominated by incoherent quantum tunneling of the Mn12-ac spin S, aided by the nuclear bath itself. However for B⊥>5 T we observe an increase of 1/T1n by several orders of magnitude up to the highest field, despite the fact that the molecular spin is in its quantum mechanical ground state. This striking observation is a consequence of the zero-point quantum fluctuations of S, which allow it to mediate the transfer of energy from the excited nuclear spin bath to the crystal lattice at much higher rates. Our experiment highlights the importance of quantum fluctuations in the interaction between an "effective two-level system" and its surrounding spin bath.
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Affiliation(s)
- A Morello
- Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300RA Leiden, The Netherlands and Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Australia, Sydney, New South Wales 2052, Australia
| | - A Millán
- Instituto de Ciencia de Materiales de Aragón, C.S.I.C. Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - L J de Jongh
- Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300RA Leiden, The Netherlands
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Jara JA, Castro-Castillo V, Saavedra-Olavarría J, Peredo L, Pavanni M, Jaña F, Letelier ME, Parra E, Becker MI, Morello A, Kemmerling U, Maya JD, Ferreira J. Antiproliferative and uncoupling effects of delocalized, lipophilic, cationic gallic acid derivatives on cancer cell lines. Validation in vivo in singenic mice. J Med Chem 2014; 57:2440-54. [PMID: 24568614 DOI: 10.1021/jm500174v] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Tumor cells principally exhibit increased mitochondrial transmembrane potential (ΔΨ(m)) and altered metabolic pathways. The therapeutic targeting and delivery of anticancer drugs to the mitochondria might improve treatment efficacy. Gallic acid exhibits a variety of biological activities, and its ester derivatives can induce mitochondrial dysfunction. Four alkyl gallate triphenylphosphonium lipophilic cations were synthesized, each differing in the size of the linker chain at the cationic moiety. These derivatives were selectively cytotoxic toward tumor cells. The better compound (TPP(+)C10) contained 10 carbon atoms within the linker chain and exhibited an IC50 value of approximately 0.4-1.6 μM for tumor cells and a selectivity index of approximately 17-fold for tumor compared with normal cells. Consequently, its antiproliferative effect was also assessed in vivo. The oxygen consumption rate and NAD(P)H oxidation levels increased in the tumor cell lines (uncoupling effect), resulting in a ΔΨ(m) decrease and a consequent decrease in intracellular ATP levels. Moreover, TPP(+)C10 significantly inhibited the growth of TA3/Ha tumors in mice. According to these results, the antineoplastic activity and safety of TPP(+)C10 warrant further comprehensive evaluation.
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Affiliation(s)
- José A Jara
- Clinical and Molecular Pharmacology Program, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, University of Chile , Independencia 1027, Santiago 8380453, Chile
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17
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Büch H, Mahapatra S, Rahman R, Morello A, Simmons MY. Spin readout and addressability of phosphorus-donor clusters in silicon. Nat Commun 2013; 4:2017. [DOI: 10.1038/ncomms3017] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2012] [Accepted: 05/16/2013] [Indexed: 11/09/2022] Open
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18
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Molina-Berríos A, Campos-Estrada C, Lapier M, Duaso J, Kemmerling U, Galanti N, Ferreira J, Morello A, López-Muñoz R, Maya JD. Protection of vascular endothelium by aspirin in a murine model of chronic Chagas' disease. Parasitol Res 2013; 112:2731-9. [PMID: 23681190 DOI: 10.1007/s00436-013-3444-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [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: 11/30/2012] [Accepted: 04/26/2013] [Indexed: 12/22/2022]
Abstract
Chronic Chagas' disease affects 10-30 % of patients infected with Trypanosoma cruzi, and it mainly manifests as cardiomyopathy. Important pathophysiological mechanisms involved in the cardiac lesions include activation of the endothelium and induced microvascular alterations. These processes involve the production of endothelial adhesion molecules and thromboxane A2, which are involved in inflammatory cell recruitment and platelet aggregation, respectively. Cyclooxygenase inhibitors such as aspirin decrease thromboxane production and alter the course of Chagas' disease, both in the acute and chronic phases. We studied the effects of the administration of low and high doses of aspirin during the early phase of T. cruzi infection, following microvascular damage in the context of a chronic murine model of Chagas' disease. The effects of both schedules were assessed at 24 and 90 days postinfection by evaluating parasitemia, mortality, and cardiac histopathological changes as well as the expression of ICAM, VCAM, and E-selectin in cardiac tissue. Thromboxane A2, soluble ICAM, and E-selectin blood levels were also measured. While aspirin did not affect parasitemia or mortality in the infected mice, it decreased both cardiac inflammatory infiltrates and thromboxane levels. Additionally, at 90 days postinfection, aspirin normalized sICAM and sE-selectin levels. Considering the improved endothelial function induced by aspirin, we propose the possibility of including this drug in clinical therapy to treat chronic Chagas' disease.
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Affiliation(s)
- Alfredo Molina-Berríos
- Molecular and Clinical Pharmacology Program, Biomedical Sciences Institute (ICBM), Faculty of Medicine, University of Chile, Independencia 1027, Santiago, Chile
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19
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Muñoz OM, Maya JD, Ferreira J, Christen P, San Martin J, López-Muñoz R, Morello A, Kemmerling U. Medicinal plants of Chile: evaluation of their anti-Trypanosoma cruzi activity. Z NATURFORSCH C 2013; 68:198-202. [PMID: 23923616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The extracts of several plants of Central Chile exhibited anti-Trypanosoma cruzi trypomastigotes activity. Most active extracts were those obtained from Podanthus ovatifolius, Berberis microphylla, Kageneckia oblonga, and Drimys winteri. The active extract of Drimys winteri (IC50 51.2 microg/mL) was purified and three drimane sesquiterpenes were obtained: polygodial, drimenol, and isodrimenin. Isodrimenin and drimenol were found to be active against the trypomastigote form of T. cruzi with IC50 values of 27.9 and 25.1 microM, respectively.
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Affiliation(s)
- Orlando M Muñoz
- Department of Chemistry, Faculty of Science, University of Chile, Santiago, Chile.
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20
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Molina-Berríos A, Campos-Estrada C, Henriquez N, Faúndez M, Torres G, Castillo C, Escanilla S, Kemmerling U, Morello A, López-Muñoz RA, Maya JD. Protective role of acetylsalicylic acid in experimental Trypanosoma cruzi infection: evidence of a 15-epi-lipoxin A₄-mediated effect. PLoS Negl Trop Dis 2013; 7:e2173. [PMID: 23638194 PMCID: PMC3630130 DOI: 10.1371/journal.pntd.0002173] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 03/08/2013] [Indexed: 01/03/2023] Open
Abstract
Chagas' disease, produced by Trypanosoma cruzi, affects more than 8 million people, producing approximately 10,000 deaths each year in Latin America. Migration of people from endemic regions to developed countries has expanded the risk of infection, transforming this disease into a globally emerging problem. PGE₂ and other eicosanoids contribute to cardiac functional deficits after infection with T. cruzi. Thus, the inhibition of host cyclooxygenase (COX) enzyme emerges as a potential therapeutic target. In vivo studies about the effect of acetylsalicylic acid (ASA) upon T. cruzi infection are controversial, and always report the effect of ASA at a single dose. Therefore, we aimed to analyze the effect of ASA at different doses in an in vivo model of infection and correlate it with the production of arachidonic acid metabolites. ASA decreased mortality, parasitemia, and heart damage in T. cruzi (Dm28c) infected mice, at the low doses of 25 and 50 mg/Kg. However, this effect disappeared when the high ASA doses of 75 and 100 mg/Kg were used. We explored whether this observation was related to the metabolic shift toward the production of 5-lipoxygenase derivatives, and although we did not observe an increase in LTB4 production in infected RAW cells and mice infected, we did find an increase in 15-epi-LXA₄ (an ASA-triggered lipoxin). We also found high levels of 15-epi-LXA₄ in T. cruzi infected mice treated with the low doses of ASA, while the high ASA doses decreased 15-epi-LXA₄ levels. Importantly, 15-epi-LXA₄ prevented parasitemia, mortality, and cardiac changes in vivo and restored the protective role in the treatment with a high dose of ASA. This is the first report showing the production of ASA-triggered lipoxins in T. cruzi infected mice, which demonstrates the role of this lipid as an anti-inflammatory molecule in the acute phase of the disease.
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Affiliation(s)
- Alfredo Molina-Berríos
- Molecular and Clinical Pharmacology Program, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad Diego Portales, Santiago, Chile
| | - Carolina Campos-Estrada
- Molecular and Clinical Pharmacology Program, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Natalia Henriquez
- Molecular and Clinical Pharmacology Program, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Mario Faúndez
- Departamento de Farmacia, Facultad de Química. Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Gloria Torres
- Molecular and Clinical Pharmacology Program, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Christian Castillo
- Anatomy and Developmental Biology Program, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Sebastián Escanilla
- Molecular and Clinical Pharmacology Program, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Ulrike Kemmerling
- Anatomy and Developmental Biology Program, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Antonio Morello
- Molecular and Clinical Pharmacology Program, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Rodrigo A. López-Muñoz
- Molecular and Clinical Pharmacology Program, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
- * E-mail: (RALM); (JDM)
| | - Juan D. Maya
- Molecular and Clinical Pharmacology Program, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
- * E-mail: (RALM); (JDM)
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Abstract
The intense interest in spin-based quantum information processing has caused an increasing overlap between the two traditionally distinct disciplines of magnetic resonance and nanotechnology. In this work we discuss rigorous design guidelines to integrate microwave circuits with charge-sensitive nanostructures, and describe how to simulate such structures accurately and efficiently. We present a new design for an on-chip, broadband, nanoscale microwave line that optimizes the magnetic field used to drive a spin-based quantum bit (or qubit) while minimizing the disturbance to a nearby charge sensor. This new structure was successfully employed in a single-spin qubit experiment, and shows that the simulations accurately predict the magnetic field values even at frequencies as high as 30 GHz.
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Affiliation(s)
- J P Dehollain
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney NSW 2052, Australia.
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22
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Muñoz OM, Maya JD, Ferreira J, Christen P, Martin JS, López-Muñoz R, Morello A, Kemmerling U. Medicinal Plants of Chile: Evaluation of their Anti-Trypanosoma cruzi Activity. Z NATURFORSCH C 2013. [DOI: 10.5560/znc.2013.68c0198] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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23
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Ramírez G, Valck C, Aguilar L, Kemmerling U, López-Muñoz R, Cabrera G, Morello A, Ferreira J, Maya JD, Galanti N, Ferreira A. Roles of Trypanosoma cruzi calreticulin in parasite-host interactions and in tumor growth. Mol Immunol 2012; 52:133-40. [PMID: 22673211 DOI: 10.1016/j.molimm.2012.05.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 05/05/2012] [Accepted: 05/07/2012] [Indexed: 12/14/2022]
Abstract
In Latin America, there are about 10-12 million people infected with Trypanosoma cruzi, the agent of Chagas' disease, one of the most important neglected tropical parasitism. Identification of molecular targets, specific for the aggressor or host cells or both, may be useful in the development of pharmacological and/or immunological therapeutic tools. Classic efforts in Chagas' disease explore those strategies. Although the immune system frequently controls parasite aggressions, sterile immunity is seldom achieved and chronic interactions are thus established. However, laboratory-modified immunologic probes aimed at selected parasite targets, may be more effective than their unmodified counterparts. Calreticulin (CRT) from vertebrates is a calcium binding protein, present mainly in the endoplasmic reticulum (ER), where it directs the conformation of proteins and controls calcium levels. We have isolated, gene-cloned, expressed and characterized T. cruzi calreticulin (TcCRT). Upon infection, the parasite can translocate this molecule from the ER to the surface, where it inhibits both the classical and lectin complement pathways. Moreover, by virtue of its capacity to bind and inactivate first complement component C1, it promotes parasite infectivity. These two related properties reside in the central domain of this molecule. A different domain, amino terminal, binds to endothelial cells, thus inhibiting their angiogenic capacity. Since tumor growth depends, to a large extent on angiogenesis, their growth is also inhibited.
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Affiliation(s)
- Galia Ramírez
- Department of Preventive Animal Medicine, University of Chile, Santiago, Chile
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24
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Salas CO, Faúndez M, Morello A, Maya JD, Tapia RA. Natural and synthetic naphthoquinones active against Trypanosoma cruzi: an initial step towards new drugs for Chagas disease. Curr Med Chem 2011; 18:144-61. [PMID: 21110810 DOI: 10.2174/092986711793979779] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Accepted: 11/15/2010] [Indexed: 11/22/2022]
Abstract
Chagas disease is one of the most important endemic diseases in Latin America, caused by Trypanosoma cruzi. The drugs used for the treatment of this disease, nifurtimox and benznidazole, are toxic and present severe side effects. The need of effective drugs, without adverse effects, has stimulated the search for new compounds with potential clinical utility. An overview of a number of natural naphthoquinones tested against T. cruzi parasites is provided. Among natural naphthoquinones, lapachol, β-lapachone and its α-isomer have demonstrated useful trypanocidal activities. In the search for new trypanocidal agents, this review outlines different structural modifications of natural quinones, as well as synthetic quinones, which have been subjected to trypanocidal studies. This review summarizes the mechanism of action and structure-activity relationships of the quinone derivatives, including some theoretical calculations that discuss the correlation of stereo electronic properties with the trypanocidal activity. In this context, this review will be useful for the development of new antichagasic drugs based mainly on structural modification of natural quinones.
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Affiliation(s)
- Cristian O Salas
- Facultad de Química, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 6094411, Chile
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25
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Maya JD, Orellana M, Ferreira J, Kemmerling U, López-Muñoz R, Morello A. Chagas disease: Present status of pathogenic mechanisms and chemotherapy. Biol Res 2010; 43:323-331. [PMID: 21249304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023] Open
Abstract
There are approximately 7.8 million people in Latin America, including Chile, who suffer from Chagas disease and another 28 million who are at risk of contracting it. Chagas is caused by the flagellate protozoan Trypanosoma cruzi. It is a chronic disease, where 20%-30% of infected individuals develop severe cardiopathy, with heart failure and potentially fatal arrhythmias. Currently, Chagas disease treatment is more effective in the acute phase, but does not always produce complete parasite eradication during indeterminate and chronic phases. At present, only nifurtimox or benznidazole have been proven to be superior to new drugs being tested. Therefore, it is necessary to find alternative approaches to treatment of chronic Chagas. The current treatment may be rendered more effective by increasing the activity of anti-Chagasic drugs or by modifying the host's immune response. We have previously shown that glutathione synthesis inhibition increases nifurtimox and benznidazole activity. In addition, there is increasing evidence that cyclooxygenase inhibitors present an important effect on T. cruzi infection. Therefore, we found that aspirin reduced the intracellular infection in RAW 264.7 cells and, decreased myocarditis extension and mortality rates in mice. However, the long-term benefit of prostaglandin inhibition for Chagasic patients is still unknown.
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Affiliation(s)
- Juan Diego Maya
- Programa de Farmacología Molecular y Clínica, ICBM, Facultad de Medicina, Universidad de Chile, Chile.
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Duaso J, Rojo G, Cabrera G, Galanti N, Bosco C, Maya J, Morello A, Kemmerling U. Trypanosoma cruzi induces tissue disorganization and destruction of chorionic villi in an ex vivo infection model of human placenta. Placenta 2010; 31:705-11. [DOI: 10.1016/j.placenta.2010.05.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 05/03/2010] [Accepted: 05/04/2010] [Indexed: 11/27/2022]
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Abstract
We present a systematic review of features due to resonant electron tunnelling, observable in transport spectroscopy experiments on quantum dots and single donors. The review covers features attributable to intrinsic properties of the dot (orbital, spin and valley states) as well as extrinsic effects (phonon/photon emission/absorption, features in the charge reservoirs, coupling to nearby charge centres). We focus on the most common operating conditions, neglecting effects due to strong coupling to the leads. By discussing the experimental signatures of each type of feature, we aim at providing practical methods to distinguish between their different physical origins. The correct classification of the resonant tunnelling features is an essential requirement to understand the details of the confining potential or to predict the performance of the dot for quantum information processing.
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Affiliation(s)
- C C Escott
- Australian Research Council Centre of Excellence for Quantum Computer Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW 2052, Australia
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28
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Maya JD, Orellana M, Ferreira J, Kemmerling U, López-Muñoz R, Morello A. Chagas disease: Present status of pathogenic mechanisms and chemotherapy. Biol Res 2010. [DOI: 10.4067/s0716-97602010000300009] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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29
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Plaza C, Pavani M, Araya-Maturana R, Pezoa J, Maya JD, Morello A, Becker MI, DE Ioannes A, Ferreira J. Chemosensitizing effect of nordihydroguaiaretic acid and its tetra-acetylated derivative on parental and multiresistant TA3 mouse mammary adenocarcinoma cells. In Vivo 2009; 23:959-967. [PMID: 20023240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
BACKGROUND Multidrug resistance (MDR) continues being the major obstacle for successful anticancer chemotherapy. MATERIALS AND METHODS The action of nordihydroguaiaretic acid (NDGA) and its tetra-acetylated derivative (NDGATA) on TA3 mouse mammary adenocarcinoma cells and their ability to restore doxorubicin (DOX), cisplatin (CPT) and methotrexate (MTX) sensitivity of the multiresistant variant TA3-MTX-R was examined. RESULTS Both NDGA and NDGATA synergistically enhanced the cytotoxicity of DOX, CPT and MTX, with a more evident effect in the TA3-MTX-R than in the TA3 cells. NDGATA was more effective than NDGA, as analyzed by the isobologram method. The combination of NDGATA and DOX also reduced the tumor growth rate in mice. Although it did not prolong the median survival time, 30% of mice showed no vestiges of tumor 200 days after implantation with either TA3 or TA3-MTX-R cells. Moreover, NDGA and NDGATA increased the accumulation of DOX and rhodamine (RHO) 123 in both cell lines. CONCLUSION NDGA and NDGATA are able to chemosensitize tumor cells and combination therapy with NDGATA and DOX is effective at inhibiting tumor growth in mice.
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Affiliation(s)
- Claudio Plaza
- Programa de Farmacología Molecular y Clínica, ICBM, Facultad de Medicina, Universidad de Chile, Casilla, Santiago, Chile
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Olea-Azar C, Rigol C, Mendizabal F, Morello A, Diego Maya J, Moncada C, Cabrera E, di Maio R, González M, Cerecetto H. ESR Spin Trapping Studies of Free Radicals Generated from Nitrofuran Derivative Analogues of Nifurtimox by Electrochemical andTrypanosoma cruziReduction. Free Radic Res 2009; 37:993-1001. [DOI: 10.1080/10715760310001598141] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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31
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Vieites M, Otero L, Santos D, Olea-Azar C, Norambuena E, Aguirre G, Cerecetto H, González M, Kemmerling U, Morello A, Diego Maya J, Gambino D. Platinum-based complexes of bioactive 3-(5-nitrofuryl)acroleine thiosemicarbazones showing anti-Trypanosoma cruzi activity. J Inorg Biochem 2009; 103:411-8. [DOI: 10.1016/j.jinorgbio.2008.12.004] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Revised: 12/09/2008] [Accepted: 12/10/2008] [Indexed: 11/27/2022]
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Brain-Isasi S, Quezada C, Pessoa H, Morello A, Kogan MJ, Álvarez-Lueje A. Determination and characterization of new benzimidazoles with activity against Trypanosoma cruzi by UV spectroscopy and HPLC. Bioorg Med Chem 2008; 16:7622-30. [DOI: 10.1016/j.bmc.2008.07.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Revised: 06/30/2008] [Accepted: 07/06/2008] [Indexed: 11/30/2022]
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Plaza C, Pavani M, Faundez M, Maya JD, Morello A, Becker MI, De Ioannes A, Cumsille MA, Ferreira J. Inhibitory effect of nordihydroguaiaretic acid and its tetra-acetylated derivative on respiration and growth of adenocarcinoma TA3 and its multiresistant variant TA3MTX-R. In Vivo 2008; 22:353-361. [PMID: 18610748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The effects of nordihydroguaiaretic acid (NDGA) and its tetraacetylated derivative (NDGATA) on the growth, oxygen consumption, adenosine 5'-triphosphate (ATP) level and viability of mouse mammary adenocarcinoma TA3 and its multiresistant variant TA3-MTX-R cell lines were determined. NDGA inhibited mitochondrial carbonyl cyanide m-chlorophenylhydrazone (CCCP)-stimulated oxygen consumption in mouse liver and tumor cells when glutamate plus malate or succinate was added as substrate. The effects were considerably weaker when respiration was supported by duroquinol, indicating that NDGA inhibited primarily mitochondrial electron flow located at some point before ubiquinone. Although NDGATA only inhibited the electron flow through complex I, it was more efficient and selective than NDGA because mouse liver mitochondria were significantly less sensitive to it than both tumor cell lines tested. NDGA and NDGATA inhibited mitochondrial ATP synthesis and, consequently, cell viability and growth rate were also decreased. NDGA and NDGATA inhibited the growth of intramuscularly implanted tumor cells, indicating that NDGATA was also antineoplastic in vivo. In conclusion, NDGATA is cytotoxic to tumor cells, provoking selective induction of mitochondrial dysfunctions, which could be interesting as potential antitumoral agent.
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Affiliation(s)
- Claudio Plaza
- Programa de Farmacología Molecular y Clínica, ICBM, Universidad de Chile, Santiago
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34
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Vieites M, Otero L, Santos D, Toloza J, Figueroa R, Norambuena E, Olea-Azar C, Aguirre G, Cerecetto H, González M, Morello A, Maya JD, Garat B, Gambino D. Platinum(II) metal complexes as potential anti-Trypanosoma cruzi agents. J Inorg Biochem 2008; 102:1033-43. [DOI: 10.1016/j.jinorgbio.2007.12.005] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Revised: 12/04/2007] [Accepted: 12/05/2007] [Indexed: 12/19/2022]
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Minutolo V, Gagliano G, Angirillo G, Minutolo O, Morello A, Rinzivillo C. Intestinal obstruction due to idiopathic sclerosing encapsulating peritonitis. Clinical report and review of literature. G Chir 2008; 29:173-176. [PMID: 18419984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The sclerosing peritonitis (SP) is a rare illness secondary to the peritoneal dialysis or due to intraperitoneal chemotherapy or the positioning of a peritoneal-jugular shunt in cirrhotic patient with refractory ascites or due to unknown other factors (idiopathic form) like in our patient. The clinical pattern is various and insidious, but when an intestinal occlusive symptomatology is presents an urgent operation is mandatory. The surgical operation is often not easy and asks for a lot of attention especially in the dialyzed subject or in patients with cirrhosis, due to the possibility of postoperative bleeding and other serious complications that can result in fatal outcome. In this report we describe surgical treatment, pathologic pattern and clinical findings of this rare disease.
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Affiliation(s)
- V Minutolo
- Dipartimento Scienze Chirurgiche, Trapianti d'Organo, Università degli Studi di Catania
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36
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Gambino D, Otero L, Maya J, Morello A, Rigol C, Barriga G, Rodriguez J, Folch C, Norambuena E, Gonzalez M, Azar C, Cerecetto H. Insight into the Bioreductive Mode of Action of Antitrypanosomal 5- Nitrofuryl Containing Thiosemicarbazones. Med Chem 2008; 4:11-7. [DOI: 10.2174/157340608783331470] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Salas C, Tapia RA, Ciudad K, Armstrong V, Orellana M, Kemmerling U, Ferreira J, Maya JD, Morello A. Trypanosoma cruzi: Activities of lapachol and α- and β-lapachone derivatives against epimastigote and trypomastigote forms. Bioorg Med Chem 2008; 16:668-74. [DOI: 10.1016/j.bmc.2007.10.038] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Revised: 10/05/2007] [Accepted: 10/15/2007] [Indexed: 11/28/2022]
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Salman Z, Chow KH, Miller RI, Morello A, Parolin TJ, Hossain MD, Keeler TA, Levy CDP, MacFarlane WA, Morris GD, Saadaoui H, Wang D, Sessoli R, Condorelli GG, Kiefl RF. Local magnetic properties of a monolayer of Mn12 single molecule magnets. Nano Lett 2007; 7:1551-5. [PMID: 17488049 DOI: 10.1021/nl070366a] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The magnetic properties of a monolayer of Mn12 single molecule magnets grafted onto a silicon (Si) substrate have been investigated using depth-controlled beta-detected nuclear magnetic resonance. A low-energy beam of spin-polarized radioactive 8Li was used to probe the local static magnetic field distribution near the Mn12 monolayer in the Si substrate. The resonance line width varies strongly as a function of implantation depth as a result of the magnetic dipolar fields generated by the Mn12 electronic magnetic moments. The temperature dependence of the line width indicates that the magnetic properties of the Mn12 moments in this low-dimensional configuration differ from bulk Mn12.
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Affiliation(s)
- Z Salman
- Clarendon Laboratory, Department of Physics, Oxford University, Parks Road, Oxford OX1 3PU, UK.
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Maya JD, Cassels BK, Iturriaga-Vásquez P, Ferreira J, Faúndez M, Galanti N, Ferreira A, Morello A. Mode of action of natural and synthetic drugs against Trypanosoma cruzi and their interaction with the mammalian host. Comp Biochem Physiol A Mol Integr Physiol 2007; 146:601-20. [PMID: 16626984 DOI: 10.1016/j.cbpa.2006.03.004] [Citation(s) in RCA: 219] [Impact Index Per Article: 12.9] [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: 10/28/2005] [Revised: 03/09/2006] [Accepted: 03/09/2006] [Indexed: 01/07/2023]
Abstract
Current knowledge of the biochemistry of Trypanosoma cruzi has led to the development of new drugs and the understanding of their mode of action. Some trypanocidal drugs such as nifurtimox and benznidazole act through free radical generation during their metabolism. T. cruzi is very susceptible to the cell damage induced by these metabolites because enzymes scavenging free radicals are absent or have very low activities in the parasite. Another potential target is the biosynthetic pathway of glutathione and trypanothione, the low molecular weight thiol found exclusively in trypanosomatids. These thiols scavenge free radicals and participate in the conjugation and detoxication of numerous drugs. Inhibition of this key pathway could render the parasite much more susceptible to the toxic action of drugs such as nifurtimox and benznidazole without affecting the host significantly. Other drugs such as allopurinol and purine analogs inhibit purine transport in T. cruzi, which cannot synthesize purines de novo. Nitroimidazole derivatives such as itraconazole inhibit sterol metabolism. The parasite's respiratory chain is another potential therapeutic target because of its many differences with the host enzyme complexes. The pharmacological modulation of the host's immune response against T. cruzi infection as a possible chemotherapeutic target is discussed. A large set of chemicals of plant origin and a few animal metabolites active against T. cruzi are enumerated and their likely modes of action are briefly discussed.
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Affiliation(s)
- Juan Diego Maya
- Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, P.O. Box 70000, Santiago 7, Santiago, Chile
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Otero L, Aguirre G, Boiani L, Denicola A, Rigol C, Olea-Azar C, Maya JD, Morello A, González M, Gambino D, Cerecetto H. Nitrofurylsemicarbazone Rhenium and Ruthenium Complexes as Anti-trypanosomal Agents. Eur J Med Chem 2006; 41:1231-9. [PMID: 16828524 DOI: 10.1016/j.ejmech.2006.05.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 05/11/2006] [Accepted: 05/18/2006] [Indexed: 11/29/2022]
Abstract
Rhenium and ruthenium complexes of the type [Re(V)OCl(2)(PPh(3))L] and [Ru(II)Cl(2)(DMSO)(2)L], where L are 5-nitrofurylsemicarbazone derivatives, were prepared in an effort to obtain new anti-trypanosomal agents combining the recognized biological activity of these metals and the trypanocidal activity of the free ligands. Rhenium complexes resulted unstable in aqueous solution not allowing their use as potential drugs. On the other hand, complexation to ruthenium of the bioactive ligands lead to the lack of antiprotozoa activity even though free radical production and redox cycling induction were detected when the compounds were incubated in presence of Trypanosoma cruzi cells. The lack of anti-trypanosomal activity of ruthenium complexes could be explained on the basis of their high protein binding capacity and their high hydrophilicity.
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Affiliation(s)
- Lucía Otero
- Cátedra de Química Inorgánica, DEC, Facultad de Química, Universidad de la República, Montevideo, Uruguay
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41
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Otero L, Vieites M, Boiani L, Denicola A, Rigol C, Opazo L, Olea-Azar C, Maya JD, Morello A, Krauth-Siegel RL, Piro OE, Castellano E, González M, Gambino D, Cerecetto H. Novel Antitrypanosomal Agents Based on Palladium Nitrofurylthiosemicarbazone Complexes: DNA and Redox Metabolism as Potential Therapeutic Targets. J Med Chem 2006; 49:3322-31. [PMID: 16722651 DOI: 10.1021/jm0512241] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.1] [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: 11/30/2022]
Abstract
In the search for new therapeutic tools against American Trypanosomiasis palladium complexes with bioactive nitrofuran-containing thiosemicarbazones as ligands were obtained. Sixteen novel palladium (II) complexes with the formulas [PdCl2(HL)] and [Pd(L)2] were synthesized, and the crystal structure of [Pd(5-nitrofuryl-3-acroleine thiosemicarbazone)2] x 3DMSO was solved by X-ray diffraction methods. Most complexes showed higher in vitro growth inhibition activity against Trypanosoma cruzi than the standard drug Nifurtimox. In most cases, the activity of the ligand was maintained or even increased as a result of palladium complexation. In addition, the complexes' mode of antitrypanosomal action was investigated. Although the complexes showed strong DNA binding, all data strongly suggest that the main trypanocidal mechanism of action is the production of oxidative stress as a result of their bioreduction and extensive redox cycling. Moreover, the complexes were found to be irreversible inhibitors of trypanothione reductase.
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Affiliation(s)
- Lucía Otero
- Departamento Estrella Campos, Facultad de Química, Universidad de la República, Montevideo, Uruguay
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42
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Gerpe A, Aguirre G, Boiani L, Cerecetto H, González M, Olea-Azar C, Rigol C, Maya JD, Morello A, Piro OE, Arán VJ, Azqueta A, de Ceráin AL, Monge A, Rojas MA, Yaluff G. Indazole N-oxide derivatives as antiprotozoal agents: Synthesis, biological evaluation and mechanism of action studies. Bioorg Med Chem 2006; 14:3467-80. [PMID: 16483783 DOI: 10.1016/j.bmc.2006.01.007] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [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: 12/05/2005] [Revised: 12/30/2005] [Accepted: 01/03/2006] [Indexed: 11/17/2022]
Abstract
A series of indazole N-oxide derivatives have been synthesized and their antichagasic and leishmanocidal properties studied. 3-Cyano-2-(4-iodophenyl)-2H-indazole N1-oxide exhibited interesting antichagasic activity on the two parasitic strains and the two parasitic stages evaluated. Furthermore, besides its trypanocidal activity, 3-cyano-2-(4-nitrophenyl)-2H-indazole N1-oxide showed leishmanocidal activity in the three parasitic strains evaluated. To gain insight into the mechanism of action, electrochemical behaviour, ESR experiment, inhibition of parasitic respiration and QSAR were performed.
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Affiliation(s)
- Alejandra Gerpe
- Departamento de Química Orgánica, Facultad de Química-Facultad de Ciencias, Universidad de la República, Iguá 4225, Montevideo 11400, Uruguay
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Frey C, Pavani M, Cordano G, Muñoz S, Rivera E, Medina J, Morello A, Diego Maya J, Ferreira J. Comparative cytotoxicity of alkyl gallates on mouse tumor cell lines and isolated rat hepatocytes. Comp Biochem Physiol A Mol Integr Physiol 2006; 146:520-7. [PMID: 16707268 DOI: 10.1016/j.cbpa.2006.03.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [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: 08/17/2005] [Revised: 03/22/2006] [Accepted: 03/23/2006] [Indexed: 11/24/2022]
Abstract
Alkyl esters of gallic acid inhibited the respiration rate of mouse sarcoma 786A and mouse mammary adenocarcinoma TA3 cell lines and its multiresistant variant TA3-MTX-R more effectively than gallic acid, both in the absence and in the presence of the uncoupler CCCP. The order of inhibition of the respiration rate by gallates in intact cells was n-octyl- approximately iso-amyl- approximately n-amyl- approximately iso-butyl->n-butyl->iso-propyl->n-propyl-gallate>>gallic acid. Sarcoma 786A was significantly more susceptible to all seven esters than the TA3 cell line. Respiration rates of the TA3-MTX-R cell line showed almost the same sensitivity to these esters as the TA3 cell line. However, hepatocytes were significantly less sensitive than all tumor cells tested. These alkyl gallates blocked mitochondrial electron flow, mainly at the NADH-CoQ segment, preventing ATP synthesis, which would lead to cellular death. These esters also inhibited, in the same order of potencies as respiration, the growth of 786A, TA3 and TA3-MTX-R cells in culture. In mice carrying TA3 or TA3-MTX-R tumor cells, an important decrease of the tumor growth rate and an increase of survival were observed when mice were treated with iso-butyl gallate alone or in combination with doxorubicin. These results indicate that alkyl gallates are selectively cytotoxic to tumor cells, which may be due to the mitochondrial dysfunctions of these cells.
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Affiliation(s)
- Christian Frey
- Department of Organic and Physical Chemistry, Faculty of Chemical and Pharmaceutical Sciences, Olivos 1007, Santiago-7, Chile
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44
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Alobid I, Benitez P, Pujols L, Maldonado M, Bernal-Sprekelsen M, Morello A, Picado C, Mullol J. Severe nasal polyposis and its impact on quality of life. The effect of a short course of oral steroids followed by long-term intranasal steroid treatment. Rhinology 2006; 44:8-13. [PMID: 16550943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
OBJECTIVES Nasal polyposis is not a life-threatening disorder but has a great impact on the quality of life. Steroids constitute the first line of treatment of nasal polyps. The aims of this study were to evaluate the quality of life in nasal polyp patients after: (1) a short course of oral steroids; and (2) a long-term treatment with intranasal steroids. METHODS Patients with severe nasal polyps received either oral prednisone (n = 60) or no steroid treatment (control group, n = 18) for 2 weeks. Patients treated with steroids were also followed-up and evaluated after 12, 24, and 48 additional weeks with intranasal budesonide treatment. RESULTS Patients with nasal polyps showed worse scores on all SF-36 domains, except for physical functioning, compared to the Spanish general population. After two weeks, patients treated with oral prednisone demonstrated a significant improvement (p < 0.05) in all impaired QoL domains compared to both control group and baseline. The mental component summary (51.0 +/- 1.2, p < 0.05) and physical component summary (51.0 +/- 0.9, p < 0.05) were improved compared to both control group and baseline. The improvement of all SF-36 domains was sustained by intranasal budesonida (p < 0.05) after 12, 24, and 48 weeks. Nasal obstruction, sense of smell, and polyp size also improved after both the oral short course and the intranasal long-term steroids treatment (p < 0.05). CONCLUSION These results suggest that the treatment with a short-course of oral steroids improves the quality of life of patients with severe nasal polyps and that this effect is maintained by a long-term treatment with intranasal steroids.
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Affiliation(s)
- Isam Alobid
- Rhinology Unit, Department of Otorhinolaryngology (ICEMEQ), Hospital Clinic, Universitat de Barcelona, Spain
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45
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Olea-Azar C, Rigol C, Mendizabal F, Cerecetto H, Maio R, Gonzalez M, Porcal W, Morello A, Repetto Y, Maya J. Novel Benzo[1,2-c]1,2,5-Oxadiazole N-Oxide Derivatives as Antichagasic Agents: Chemical and Biological Studies. LETT DRUG DES DISCOV 2005. [DOI: 10.2174/1570180054038341] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Abstract
Peripheral primitive neuroectodermal tumors are highly malignant small cell neoplasms. A 27-year-old female presented with a 6-month history of right-sided facial pain and progressive weakness of the facial muscles. She had non-pulsative tinnitus, progressive right hearing loss and facial palsy. T2-weighted MRI showed a heterogeneous hyperintense lesion invading the right internal auditory canal. Surgical removal was performed. Pathological examination showed sheets of small cells with irregular nuclei. Immunohistochemical studies demonstrated positive immunoreactivity for neuron-specific enolase, synaptophysin, chromogranin, vimentin, S-100 protein and p30-32 MIC-2 gene product. The patient was treated with chemotherapy (etoposide, vincristine, adriamycin, ifosfamide and actinomycin D) and radiotherapy. After 65 months of follow-up, the patient presented with cervical metastasis. Radical cervical dissection was performed and the patient was treated with a second course of chemotherapy. At control MRI after 29 months of follow-up the patient showed no signs of local recurrence or distant metastasis.
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MESH Headings
- Adult
- Biomarkers, Tumor/analysis
- Cerebellar Neoplasms/pathology
- Cerebellar Neoplasms/therapy
- Cerebellopontine Angle/pathology
- Cerebellopontine Angle/surgery
- Ear, Inner/pathology
- Ear, Inner/surgery
- Female
- Follow-Up Studies
- Head and Neck Neoplasms/pathology
- Head and Neck Neoplasms/therapy
- Humans
- Magnetic Resonance Imaging
- Neoplasm Invasiveness
- Neoplasms, Second Primary/pathology
- Neoplasms, Second Primary/therapy
- Neuroectodermal Tumors, Primitive, Peripheral/pathology
- Neuroectodermal Tumors, Primitive, Peripheral/surgery
- Neuroectodermal Tumors, Primitive, Peripheral/therapy
- Retreatment
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Affiliation(s)
- Isam Alobid
- Department of Otorhinolaryngology, Hospital Clínic, Barcelona, Spain.
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Abstract
The high prevalence of habitual snoring (35% of the general population) and the increasing demand for an effective treatment have led, in the last decade, to the generalisation of laser-assisted uvulopalatoplasty (LAUP). However, acceptable studies on its effectiveness are lacking. The present randomised, placebo-controlled study included 25 nonapnoeic and mild obstructive sleep apnoea snorers to evaluate LAUP effectiveness for snoring. Group I received a one-stage LAUP treatment and group II a placebo (simulated snore surgery followed by an oral placebo). Before each treatment and 3 months after, the variables and procedures assessed were: body weight; sleepiness (Epworth sleepiness scale); quality of life (SF-36); subjective snoring intensity (0-10 analogue scale); objective snoring intensity (average decibel intensity); snoring index (number of snores per hour); and apnoea/hypopnea index. No differences were observed in body weight, sleepiness, quality of life, subjective and objective intensity, and frequency of snoring, and apnoea/hypopnea index between the groups before and 3 months after treatment. In conclusion, this study provides evidence of the lack of effectiveness of one-stage laser-assisted uvulopalatoplasty for snoring in nonapnoeic and mild obstructive sleep apnoea patients, with the result that it does not meet the expectations generated by the procedure.
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Affiliation(s)
- F Larrosa
- Otorhinolaryngology Service, Institut d'Investigacions Biomediques August Pi Sunyer, University of Barcelona, Barcelona, Spain
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48
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Faundez M, Pino L, Letelier P, Ortiz C, López R, Seguel C, Ferreira J, Pavani M, Morello A, Maya JD. Buthionine sulfoximine increases the toxicity of nifurtimox and benznidazole to Trypanosoma cruzi. Antimicrob Agents Chemother 2005; 49:126-30. [PMID: 15616285 PMCID: PMC538915 DOI: 10.1128/aac.49.1.126-130.2005] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [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: 07/16/2004] [Revised: 08/09/2004] [Accepted: 09/05/2004] [Indexed: 11/20/2022] Open
Abstract
l-Buthionine (S,R)-sulfoximine (BSO) increased the toxicity of nifurtimox and benznidazole toward the epimastigote, trypomastigote, and amastigote forms of Trypanosoma cruzi. BSO at 500 muM decreased total glutathione-derived thiols by 70 to 80% in 48 h. In epimastigotes, 500 muM BSO decreased the concentration of nifurtimox needed to inhibit constant growth of the parasites by 50%, from 14.0 to 9.0 muM, and decreased that of benznidazole from 43.6 to 24.1 muM. The survival of epimastigotes or trypomastigotes treated with nifurtimox or benznidazole, as measured by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) reduction, was significantly decreased by 500 muM BSO. In Vero cells infected with amastigotes, 25 muM BSO was able to potentiate the effect of nifurtimox and benznidazole as measured by the percentage of infected Vero cells multiplied by the average number of intracellular amastigotes (endocytic index). At 0.5 muM nifurtimox, the proportion of Vero cells infected decreased from 27 to 20% and the endocytic index decreased from 2,500 to 980 when 25 muM BSO was added. Similar results were obtained with benznidazole- and BSO-benznidazole-treated cells. This study indicates that potentiation of nifurtimox or benznidazole by BSO could decrease the clinical dose of both drugs and diminish the side effects or the length of therapy.
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Affiliation(s)
- Mario Faundez
- University of Chile, Faculty of Medicine, Molecular and Clinical Pharmacology Program, P.O. Box 70000, Santiago 7, Chile
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Tapia RA, López C, Morello A, Maya JD, Valderrama JA. A Convenient Synthesis of Benzo[g]pyrrolo[3,2-c]quinoline-6,11-diones. SYNTHESIS-STUTTGART 2005. [DOI: 10.1055/s-2005-861802] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Morello A, Bakharev ON, Brom HB, Sessoli R, de Jongh LJ. Nuclear spin dynamics in the quantum regime of a single-molecule magnet. Phys Rev Lett 2004; 93:197202. [PMID: 15600873 DOI: 10.1103/physrevlett.93.197202] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2003] [Indexed: 05/24/2023]
Abstract
We show that the nuclear spin dynamics in the single-molecule magnet Mn12-ac below 1 K is governed by quantum tunneling fluctuations of the cluster spins, combined with intercluster nuclear spin diffusion. We also obtain the first experimental proof that-surprisingly-even deep in the quantum regime the nuclear spins remain in good thermal contact with the lattice phonons. We propose a simple model for how T-independent tunneling fluctuations can relax the nuclear polarization to the lattice that may serve as a framework for more sophisticated theories.
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Affiliation(s)
- A Morello
- Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300RA Leiden, The Netherlands.
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