1
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Chen Y, Bâldea I, Yu Y, Liang Z, Li MD, Koren E, Xie Z. CP-AFM Molecular Tunnel Junctions with Alkyl Backbones Anchored Using Alkynyl and Thiol Groups: Microscopically Different Despite Phenomenological Similarity. Langmuir 2024; 40:4410-4423. [PMID: 38348971 PMCID: PMC10906003 DOI: 10.1021/acs.langmuir.3c03759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/24/2024] [Accepted: 01/24/2024] [Indexed: 02/28/2024]
Abstract
In this paper, we report results on the electronic structure and transport properties of molecular junctions fabricated via conducting probe atomic force microscopy (CP-AFM) using self-assembled monolayers (SAMs) of n-alkyl chains anchored with acetylene groups (CnA; n = 8, 9, 10, and 12) on Ag, Au, and Pt electrodes. We found that the current-voltage (I-V) characteristics of CnA CP-AFM junctions can be very accurately reproduced by the same off-resonant single-level model (orSLM) successfully utilized previously for many other junctions. We demonstrate that important insight into the energy-level alignment can be gained from experimental data of transport (processed via the orSLM) and ultraviolet photoelectron spectroscopy combined with ab initio quantum chemical information based on the many-body outer valence Green's function method. Measured conductance GAg < GAu < GPt is found to follow the same ordering as the metal work function ΦAu < ΦAu < ΦPt, a fact that points toward a transport mediated by an occupied molecular orbital (MO). Still, careful data analysis surprisingly revealed that transport is not dominated by the ubiquitous HOMO but rather by the HOMO-1. This is an important difference from other molecular tunnel junctions with p-type HOMO-mediated conduction investigated in the past, including the alkyl thiols (CnT) to which we refer in view of some similarities. Furthermore, unlike in CnT and other junctions anchored with thiol groups investigated in the past, the AFM tip causes in CnA an additional MO shift, whose independence of size (n) rules out significant image charge effects. Along with the prevalence of the HOMO-1 over the HOMO, the impact of the "second" (tip) electrode on the energy level alignment is another important finding that makes the CnA and CnT junctions different. What ultimately makes CnA unique at the microscopic level is a salient difference never reported previously, namely, that CnA's alkyne functional group gives rise to two energetically close (HOMO and HOMO-1) orbitals. This distinguishes the present CnA from the CnT, whose HOMO stemming from its thiol group is well separated energetically from the other MOs.
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Affiliation(s)
- Yuhong Chen
- Department
of Materials Science and Engineering, Technion-Israel
Institute of Technology, Haifa 3200003, Israel
- Department
of Materials Science and Engineering, Guangdong Provincial Key Laboratory
of Materials and Technologies for Energy Conversion (MATEC), Guangdong Technion-Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong 515063, China
| | - Ioan Bâldea
- Theoretical
Chemistry, Heidelberg University, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany
| | - Yongxin Yu
- Department
of Materials Science and Engineering, Guangdong Provincial Key Laboratory
of Materials and Technologies for Energy Conversion (MATEC), Guangdong Technion-Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong 515063, China
| | - Zining Liang
- Department
of Materials Science and Engineering, Guangdong Provincial Key Laboratory
of Materials and Technologies for Energy Conversion (MATEC), Guangdong Technion-Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong 515063, China
| | - Ming-De Li
- Department
of Chemistry and Key Laboratory for Preparation and Application of
Ordered Structural Materials of Guangdong Province, Shantou University, Shantou 515063, China
| | - Elad Koren
- Department
of Materials Science and Engineering, Technion-Israel
Institute of Technology, Haifa 3200003, Israel
| | - Zuoti Xie
- Department
of Materials Science and Engineering, Technion-Israel
Institute of Technology, Haifa 3200003, Israel
- Department
of Materials Science and Engineering, Guangdong Provincial Key Laboratory
of Materials and Technologies for Energy Conversion (MATEC), Guangdong Technion-Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong 515063, China
- Quantum
Science Center of Guangdong-Hong Kong-Macao Greater Bay Area (Guangdong), Shenzhen-Hong Kong International Science and Technology
Park, No. 3 Binglang
Road, Futian District, Shenzhen, Guangdong 518048, China
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2
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Mukherjee S, Dutta D, Ghosh A, Koren E. Graphene-In 2Se 3 van der Waals Heterojunction Neuristor for Optical In-Memory Bimodal Operation. ACS Nano 2023; 17:22287-22298. [PMID: 37930899 DOI: 10.1021/acsnano.3c03820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
Functional diversification at the single-device level has become essential for emerging optical neural network (ONN) development. Stable ferroelectricity harnessed with strong light sensitivity in α-In2Se3 holds great potential for developing ultrathin neuromorphic devices. Herein, we demonstrated an all-2D van der Waals heterostructure-based programmable synaptic field effect transistor (FET) utilizing a ferroelectric α-In2Se3 nanosheet and monolayer graphene. The devices exhibited reconfigurable, multilevel nonvolatile memory (NVM) states, which can be successively modulated by multiple dual-mode (optical and electrical) stimuli and thereby used to realize energy-efficient, heterosynaptic functionalities in a biorealistic fashion. Furthermore, under light illumination, the prototypical device can toggle between volatile (photodetector) and nonvolatile optical random-access memory (ORAM) logic operation, depending upon the ferroelectric-dipole induced band adjustment. Finally, plasticity modulation from short-term to prominent long-term characteristics over a wide dynamic range was demonstrated. The inherent operation mechanism owing to the switchable polarization-induced electronic band alignment and bidirectional barrier height modulation at the heterointerface was revealed by conjugated electronic transport and Kelvin-probe force microscopy (KPFM) measurements. Overall, robust (opto)electronic weight controllability for integrated in-sensor and in-memory logic processors and multibit ORAM systems was readily accomplished by the synergistic ferrophotonic heterostructure properties. Our presented results facilitate the technological implementation of versatile all-2D heterosynapses for next-generation perception, optoelectronic logic systems, and Internet-of-Things (IoT) entities.
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Affiliation(s)
- Subhrajit Mukherjee
- Nanoscale Electronic Materials and Devices Laboratory, Faculty of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Debopriya Dutta
- Nanoscale Electronic Materials and Devices Laboratory, Faculty of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Anurag Ghosh
- Nanoscale Electronic Materials and Devices Laboratory, Faculty of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Elad Koren
- Nanoscale Electronic Materials and Devices Laboratory, Faculty of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
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3
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Duan X, Wang B, Rong K, Liu CL, Gorovoy V, Mukherjee S, Kleiner V, Koren E, Hasman E. Valley-addressable monolayer lasing through spin-controlled Berry phase photonic cavities. Science 2023; 381:1429-1432. [PMID: 37769087 DOI: 10.1126/science.adi7196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 08/25/2023] [Indexed: 09/30/2023]
Abstract
The spin-valley coupling between circularly polarized light and valley excitons in transition metal dichalcogenides provides the opportunity to generate and manipulate spin information by exploiting the valley degree of freedom. Here, we demonstrate a room-temperature valley-addressable tungsten disulfide monolayer laser in which the spin of lasing is controlled by the spin of pump without magnetic fields. This effect was achieved by integrating a tungsten disulfide monolayer into a photonic cavity that supports two orthogonal spin modes with high quality factors. The spin-pumped lasing effectively broke the population symmetry of valley excitons, resulting in highly coherent emission with valley-switchable radiation modes due to distinct laser thresholds. Our scheme provides a nanophotonic platform to develop versatile coherent spin-light sources operating at room temperature by actively manipulating spin-valley coupling in light-matter interactions.
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Affiliation(s)
- Xiaoyang Duan
- Atomic-Scale Photonics Laboratory, Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Bo Wang
- State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Kexiu Rong
- Atomic-Scale Photonics Laboratory, Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Chieh-Li Liu
- Atomic-Scale Photonics Laboratory, Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Vladi Gorovoy
- Atomic-Scale Photonics Laboratory, Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Subhrajit Mukherjee
- Faculty of Materials Science and Engineering, Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Vladimir Kleiner
- Atomic-Scale Photonics Laboratory, Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Elad Koren
- Faculty of Materials Science and Engineering, Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Erez Hasman
- Atomic-Scale Photonics Laboratory, Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion - Israel Institute of Technology, Haifa 3200003, Israel
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4
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Rong K, Duan X, Wang B, Reichenberg D, Cohen A, Liu CL, Mohapatra PK, Patsha A, Gorovoy V, Mukherjee S, Kleiner V, Ismach A, Koren E, Hasman E. Spin-valley Rashba monolayer laser. Nat Mater 2023; 22:1085-1093. [PMID: 37414946 DOI: 10.1038/s41563-023-01603-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 06/07/2023] [Indexed: 07/08/2023]
Abstract
Direct-bandgap transition metal dichalcogenide monolayers are appealing candidates to construct atomic-scale spin-optical light sources owing to their valley-contrasting optical selection rules. Here we report on a spin-optical monolayer laser by incorporating a WS2 monolayer into a heterostructure microcavity supporting high-Q photonic spin-valley resonances. Inspired by the creation of valley pseudo-spins in monolayers, the spin-valley modes are generated from a photonic Rashba-type spin splitting of a bound state in the continuum, which gives rise to opposite spin-polarized ±K valleys due to emergent photonic spin-orbit interaction under inversion symmetry breaking. The Rashba monolayer laser shows intrinsic spin polarizations, high spatial and temporal coherence, and inherent symmetry-enabled robustness features, enabling valley coherence in the WS2 monolayer upon arbitrary pump polarizations at room temperature. Our monolayer-integrated spin-valley microcavities open avenues for further classical and non-classical coherent spin-optical light sources exploring both electron and photon spins.
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Affiliation(s)
- Kexiu Rong
- Atomic-Scale Photonics Laboratory, Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion - Israel Institute of Technology, Haifa, Israel
| | - Xiaoyang Duan
- Atomic-Scale Photonics Laboratory, Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion - Israel Institute of Technology, Haifa, Israel
| | - Bo Wang
- State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
| | - Dror Reichenberg
- Atomic-Scale Photonics Laboratory, Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion - Israel Institute of Technology, Haifa, Israel
| | - Assael Cohen
- Department of Materials Science and Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Chieh-Li Liu
- Atomic-Scale Photonics Laboratory, Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion - Israel Institute of Technology, Haifa, Israel
| | - Pranab K Mohapatra
- Department of Materials Science and Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Avinash Patsha
- Department of Materials Science and Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Vladi Gorovoy
- Atomic-Scale Photonics Laboratory, Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion - Israel Institute of Technology, Haifa, Israel
| | - Subhrajit Mukherjee
- Faculty of Materials Science and Engineering, Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion-Israel Institute of Technology, Haifa, Israel
| | - Vladimir Kleiner
- Atomic-Scale Photonics Laboratory, Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion - Israel Institute of Technology, Haifa, Israel
| | - Ariel Ismach
- Department of Materials Science and Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Elad Koren
- Faculty of Materials Science and Engineering, Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion-Israel Institute of Technology, Haifa, Israel
| | - Erez Hasman
- Atomic-Scale Photonics Laboratory, Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion - Israel Institute of Technology, Haifa, Israel.
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5
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Dutta D, Mukherjee S, Uzhansky M, Mohapatra PK, Ismach A, Koren E. Edge-Based Two-Dimensional α-In 2Se 3-MoS 2 Ferroelectric Field Effect Device. ACS Appl Mater Interfaces 2023; 15:18505-18515. [PMID: 37000129 DOI: 10.1021/acsami.3c00590] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Heterostructures based on two-dimensional materials offer the possibility to achieve synergistic functionalities, which otherwise remain secluded by their individual counterparts. Herein, ferroelectric polarization switching in α-In2Se3 has been utilized to engineer multilevel nonvolatile conduction states in a partially overlapping α-In2Se3-MoS2-based ferroelectric semiconducting field effect device. In particular, we demonstrate how the intercoupled ferroelectric nature of α-In2Se3 allows to nonvolatilely switch between n-i and n-i-n type junction configurations based on a novel edge state actuation mechanism, paving the way for subnanometric scale nonvolatile device miniaturization. Furthermore, the induced asymmetric polarization enables enhanced photogenerated carriers' separation, resulting in an extremely high photoresponse of ∼1275 A/W in the visible range and strong nonvolatile modulation of the bright A- and B- excitonic emission channels in the overlaying MoS2 monolayer. Our results show significant potential to harness the switchable polarization in partially overlapping α-In2Se3-MoS2 based FeFETs to engineer multimodal, nonvolatile nanoscale electronic and optoelectronic devices.
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Affiliation(s)
- Debopriya Dutta
- Nanoscale Electronic Materials and Devices Laboratory, Faculty of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Subhrajit Mukherjee
- Nanoscale Electronic Materials and Devices Laboratory, Faculty of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Michael Uzhansky
- Nanoscale Electronic Materials and Devices Laboratory, Faculty of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Pranab K Mohapatra
- Department of Materials Science and Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv 6997801, Israel
| | - Ariel Ismach
- Department of Materials Science and Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv 6997801, Israel
| | - Elad Koren
- Nanoscale Electronic Materials and Devices Laboratory, Faculty of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
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6
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Oz A, Dutta D, Nitzan A, Hod O, Koren E. Edge State Quantum Interference in Twisted Graphitic Interfaces. Adv Sci (Weinh) 2022; 9:e2102261. [PMID: 35285174 PMCID: PMC9108635 DOI: 10.1002/advs.202102261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 12/30/2021] [Indexed: 06/14/2023]
Abstract
Zigzag edges in graphitic systems exhibit localized electronic states that drastically affect their properties. Here, room-temperature charge transport experiments across a single graphitic interface are reported, in which the interlayer current is confined to the contact edges. It is shown that the current exhibits pronounced oscillations of up to ≈40 µA with a dominant period of ≈5 Å with respect to lateral displacement that do not directly correspond to typical graphene lattice spacing. The origin of these features is computationally rationalized as quantum mechanical interference of localized edge states showing significant amplitude and interlayer coupling variations as a function of the interface stacking configuration. Such interference effects may therefore dominate the transport properties of low-dimensional graphitic interfaces.
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Affiliation(s)
- Annabelle Oz
- Department of Physical ChemistrySchool of ChemistryThe Raymond and Beverly Sackler Faculty of Exact Sciences and The Sackler Center for Computational Molecular and Materials ScienceTel Aviv UniversityTel Aviv6997801Israel
| | - Debopriya Dutta
- Faculty of Materials Science and Engineering and the Russell Berrie Nanotechnology InstituteTechnion – Israel Institute of TechnologyHaifa3200003Israel
| | - Abraham Nitzan
- Department of Physical ChemistrySchool of ChemistryThe Raymond and Beverly Sackler Faculty of Exact Sciences and The Sackler Center for Computational Molecular and Materials ScienceTel Aviv UniversityTel Aviv6997801Israel
- Department of ChemistryUniversity of PennsylvaniaPhiladelphiaPA19103USA
| | - Oded Hod
- Department of Physical ChemistrySchool of ChemistryThe Raymond and Beverly Sackler Faculty of Exact Sciences and The Sackler Center for Computational Molecular and Materials ScienceTel Aviv UniversityTel Aviv6997801Israel
| | - Elad Koren
- Faculty of Materials Science and Engineering and the Russell Berrie Nanotechnology InstituteTechnion – Israel Institute of TechnologyHaifa3200003Israel
- The Nancy and Stephen Grand Technion Energy ProgramTechnion – Israel Institute of TechnologyHaifa3200003Israel
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7
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Katznelson S, Cohn B, Sufrin S, Amit T, Mukherjee S, Kleiner V, Mohapatra P, Patsha A, Ismach A, Refaely-Abramson S, Hasman E, Koren E. Bright excitonic multiplexing mediated by dark exciton transition in two-dimensional TMDCs at room temperature. Mater Horiz 2022; 9:1089-1098. [PMID: 35083477 DOI: 10.1039/d1mh01186c] [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] [Indexed: 06/14/2023]
Abstract
2D-semiconductors with strong light-matter interaction are attractive materials for integrated and tunable optical devices. Here, we demonstrate room-temperature wavelength multiplexing of the two-primary bright excitonic channels (Ab-, Bb-) in monolayer transition metal dichalcogenides (TMDs) arising from a dark exciton mediated transition. We present how tuning dark excitons via an out-of-plane electric field cedes the system equilibrium from one excitonic channel to the other, encoding the field polarization into wavelength information. In addition, we demonstrate how such exciton multiplexing is dictated by thermal-scattering by performing temperature dependent photoluminescence measurements. Finally, we demonstrate experimentally and theoretically how excitonic mixing can explain preferable decay through dark states in MoX2 in comparison with WX2 monolayers. Such field polarization-based manipulation of excitonic transitions can pave the way for novel photonic device architectures.
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Affiliation(s)
- Shaul Katznelson
- Nanoscale Electronic Materials and Devices Laboratory, Faculty of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel.
- Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Bar Cohn
- Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion - Israel Institute of Technology, Haifa 3200003, Israel
- Atomic-Scale Photonics Laboratory, Faculty of Mechanical Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Shmuel Sufrin
- Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion - Israel Institute of Technology, Haifa 3200003, Israel
- Atomic-Scale Photonics Laboratory, Faculty of Mechanical Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Tomer Amit
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Subhrajit Mukherjee
- Nanoscale Electronic Materials and Devices Laboratory, Faculty of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel.
| | - Vladimir Kleiner
- Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion - Israel Institute of Technology, Haifa 3200003, Israel
- Atomic-Scale Photonics Laboratory, Faculty of Mechanical Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Pranab Mohapatra
- Department of Materials Science and Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv, 6997801, Israel
| | - Avinash Patsha
- Department of Materials Science and Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv, 6997801, Israel
| | - Ariel Ismach
- Department of Materials Science and Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv, 6997801, Israel
| | - Sivan Refaely-Abramson
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Erez Hasman
- Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion - Israel Institute of Technology, Haifa 3200003, Israel
- Atomic-Scale Photonics Laboratory, Faculty of Mechanical Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Elad Koren
- Nanoscale Electronic Materials and Devices Laboratory, Faculty of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel.
- Russell Berrie Nanotechnology Institute, and Helen Diller Quantum Center, Technion - Israel Institute of Technology, Haifa 3200003, Israel
- The Nancy and Stephen Grand Technion Energy Program, Technion - Israel Institute of Technology, Haifa 3200003, Israel
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8
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Mukherjee S, Koren E. Indium Selenide (In
2
Se
3
) – An Emerging Van‐der‐Waals Material for Photodetection and Non‐Volatile Memory Applications. Isr J Chem 2022. [DOI: 10.1002/ijch.202100112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Subhrajit Mukherjee
- Nanoscale Electronic Materials & Devices Laboratory, Faculty of Materials Science and Engineering, Technion – Israel Institute of Technology 3200003 Haifa Israel
| | - Elad Koren
- Nanoscale Electronic Materials & Devices Laboratory, Faculty of Materials Science and Engineering, Technion – Israel Institute of Technology 3200003 Haifa Israel
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9
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Brill AR, Kafri A, Mohapatra PK, Ismach A, de Ruiter G, Koren E. Modulating the Optoelectronic Properties of MoS 2 by Highly Oriented Dipole-Generating Monolayers. ACS Appl Mater Interfaces 2021; 13:32590-32597. [PMID: 34190537 DOI: 10.1021/acsami.1c09035] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The noncovalent functionalization of two-dimensional materials (2DMs) with bespoke organic molecules is of central importance for future nanoscale electronic devices. Of particular interest is the incorporation of molecular functionalities that can modulate the physicochemical properties of the 2DMs via noninvasive external stimuli. In this study, we present the reversible modulation of the photoluminescence, spectroscopic properties (Raman), and charge transport characteristics of molybdenum disulfide (MoS2)-based devices via photoisomerization of a self-assembled monolayer of azobenzene-modified triazatriangulene molecules. The observed (opto)electronic modulations are explained by the n-type doping of the MoS2 lattice induced by the photoisomerization of the highly ordered azobenzene monolayer. This novel behavior could have profound effects on future composite 2DM-based (opto)electronics.
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Affiliation(s)
- Adam R Brill
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Technion City, Haifa 3200008, Israel
- Faculty of Materials Science and Engineering, Technion - Israel Institute of Technology, Technion City, Haifa 3200008, Israel
| | - Alonit Kafri
- Faculty of Materials Science and Engineering, Technion - Israel Institute of Technology, Technion City, Haifa 3200008, Israel
| | - Pranab K Mohapatra
- Department of Materials Science and Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv 6997801, Israel
| | - Ariel Ismach
- Department of Materials Science and Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv 6997801, Israel
| | - Graham de Ruiter
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Technion City, Haifa 3200008, Israel
| | - Elad Koren
- Faculty of Materials Science and Engineering, Technion - Israel Institute of Technology, Technion City, Haifa 3200008, Israel
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10
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Hui F, Liu P, Hodge SA, Carey T, Wen C, Torrisi F, Galhena DTL, Tomarchio F, Lin Y, Moreno E, Roldan JB, Koren E, Ferrari AC, Lanza M. In Situ Observation of Low-Power Nano-Synaptic Response in Graphene Oxide Using Conductive Atomic Force Microscopy. Small 2021; 17:e2101100. [PMID: 34081416 DOI: 10.1002/smll.202101100] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/27/2021] [Indexed: 06/12/2023]
Abstract
Multiple studies have reported the observation of electro-synaptic response in different metal/insulator/metal devices. However, most of them analyzed large (>1 µm2 ) devices that do not meet the integration density required by industry (1010 devices/mm2 ). Some studies emploied a scanning tunneling microscope (STM) to explore nano-synaptic response in different materials, but in this setup there is a nanogap between the insulator and one of the metallic electrodes (i.e., the STM tip), not present in real devices. Here, it is demonstrated how to use conductive atomic force microscopy to explore the presence and quality of nano-synaptic response in confined areas <50 nm2 . Graphene oxide (GO) is selected due to its easy fabrication. Metal/GO/metal nano-synapses exhibit potentiation and paired pulse facilitation with low write current levels <1 µA (i.e., power consumption ≈3 µW), controllable excitatory post-synaptic currents, and long-term potentiation and depression. The results provide a new method to explore nano-synaptic plasticity at the nanoscale, and point to GO as an important candidate for the fabrication of ultrasmall (<50 nm2 ) electronic synapses fulfilling the integration density requirements of neuromorphic systems.
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Affiliation(s)
- Fei Hui
- Department of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa, 3200003, Israel
| | - Peisong Liu
- Institute of Functional Nano & Soft Materials, Collaborative Innovation Center of Suzhou Nanoscience and Technology, Soochow University, 199 Ren-Ai Road, Suzhou, 215123, China
| | - Stephen A Hodge
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, CB3 0FA, UK
| | - Tian Carey
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, CB3 0FA, UK
| | - Chao Wen
- Institute of Functional Nano & Soft Materials, Collaborative Innovation Center of Suzhou Nanoscience and Technology, Soochow University, 199 Ren-Ai Road, Suzhou, 215123, China
| | - Felice Torrisi
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, CB3 0FA, UK
| | - D Thanuja L Galhena
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, CB3 0FA, UK
| | - Flavia Tomarchio
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, CB3 0FA, UK
| | - Yue Lin
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, CB3 0FA, UK
| | - Enrique Moreno
- UJM-Saint-Etienne, CNRS, Institute of Optics Graduate School, University of Lyon, Laboratoire Hubert Curien UMR5516, St-Etienne, F-42023, France
| | - Juan B Roldan
- Departamento de Electrónica y Tecnología de Computadores, Universidad de Granada, Facultad de Ciencias, Avd. Fuentenueva s/n, Granada, 18071, Spain
| | - Elad Koren
- Department of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa, 3200003, Israel
| | - Andrea C Ferrari
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, CB3 0FA, UK
| | - Mario Lanza
- Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
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11
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Brill AR, Biswas S, Caspary Toroker M, de Ruiter G, Koren E. Dipole-Induced Raman Enhancement Using Noncovalent Azobenzene-Functionalized Self-Assembled Monolayers on Graphene Terraces. ACS Appl Mater Interfaces 2021; 13:10271-10278. [PMID: 33591709 DOI: 10.1021/acsami.0c20454] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Graphene is a promising material in the field of interface science, especially for noncovalent functionalization, sensing, and for applications in catalysis and nanoelectronics. The noncovalent self-assembly of aromatic molecules on graphene promotes electronic coupling through π-π interactions that allows for quenching of the fluorescence of adsorbent molecules and the enhancement of their Raman spectra via graphene-enhanced Raman spectroscopy (GERS). Although recent work has explored the Raman enhancement on mono- and bilayer graphene, the layer dependence of both electronic phenomena (i.e., fluorescence quenching and Raman enhancement) has largely remained underexplored. Similarly, the effect of near-surface molecular dipoles on GERS has sparsely been examined. In this work, we employ self-assembled monolayers of azobenzene-decorated triazatriangulene molecules (AzoTATA) on graphene terraces to examine the effect of switchable molecular dipoles on the GERS effect, which occurs as a function of azobenzene photoisomerization. Furthermore, using empirical and computational methods, we present a systematic study for deriving the mechanism of GERS enhancement and fluorescence quenching on graphene terraces.
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Affiliation(s)
- Adam R Brill
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 3200008, Israel
- Faculty of Materials Science and Engineering, Technion-Israel Institute of Technology, Technion City, Haifa 3200008, Israel
| | - Santu Biswas
- Faculty of Materials Science and Engineering, Technion-Israel Institute of Technology, Technion City, Haifa 3200008, Israel
| | - Maytal Caspary Toroker
- Faculty of Materials Science and Engineering, Technion-Israel Institute of Technology, Technion City, Haifa 3200008, Israel
- The Nancy and Stephen Grand Technion Energy Program, Technion-Israel Institute of Technology, Haifa 3200008, Israel
| | - Graham de Ruiter
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 3200008, Israel
| | - Elad Koren
- Faculty of Materials Science and Engineering, Technion-Israel Institute of Technology, Technion City, Haifa 3200008, Israel
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12
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Kafri A, Dutta D, Mukherjee S, Mohapatra PK, Ismach A, Koren E. Maskless Device Fabrication and Laser-Induced Doping in MoS 2 Field Effect Transistors Using a Thermally Activated Cyclic Polyphthalaldehyde Resist. ACS Appl Mater Interfaces 2021; 13:5399-5405. [PMID: 33464810 DOI: 10.1021/acsami.0c19194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We present a novel maskless device fabrication technique for rapid prototyping of two-dimensional (2D)-based electronic materials. The technique is based on a thermally activated and self-developed cyclic polyphthalaldehyde (c-PPA) resist using a commercial Raman system and 532 nm laser illumination. Following the successful customization of electrodes to form field effect transistors based on MoS2 monolayers, the laser-induced electronic doping of areas beneath the metal contacts that were exposed during lithography was investigated using both surface potential mapping and device characterization. An effective change in the doping level was introduced depending on the laser intensity, i.e., low laser powers resulted in p-doping, while high laser powers resulted in n-doping. Fabricated devices present a low contact resistance down to 10 kΩ·μm at a back-gate voltage of VG = 80 V, which is attributed to the laser-induced n-type doping at the metal contact regions.
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Affiliation(s)
- Alonit Kafri
- Faculty of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Debopriya Dutta
- Faculty of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Subhrajit Mukherjee
- Faculty of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Pranab K Mohapatra
- Department of Materials Science and Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv 6997801, Israel
| | - Ariel Ismach
- Department of Materials Science and Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv 6997801, Israel
| | - Elad Koren
- Faculty of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
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13
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Mukherjee S, Dutta D, Mohapatra PK, Dezanashvili L, Ismach A, Koren E. Scalable Integration of Coplanar Heterojunction Monolithic Devices on Two-Dimensional In 2Se 3. ACS Nano 2020; 14:17543-17553. [PMID: 33210905 DOI: 10.1021/acsnano.0c08146] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The formation of lateral heterojunction arrays within two-dimensional (2D) crystals is an essential step to realize high-density, ultrathin electro-optical integrated circuits, although the assembling of such structures remains elusive. Here we demonstrated a rapid, scalable, and site-specific integration of lateral 2D heterojunction arrays using few-layer indium selenide (In2Se3). We use a scanning laser probe to locally convert In2Se3 into In2O3, which shows a significant increase in carrier mobility and transforms the metal-semiconductor junctions from Schottky to ohmic type. In addition, a lateral p-n heterojunction diode within a single nanosheet is demonstrated and utilized for photosensing applications. The presented method enables high-yield, site-specific formation of lateral 2D In2Se3-In2O3-based hybrid heterojunctions for realizing nanoscale devices with multiple advanced functionalities.
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Affiliation(s)
- Subhrajit Mukherjee
- Nanoscale Electronic Materials and Devices Laboratory, Faculty of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa, 3200003, Israel
| | - Debopriya Dutta
- Nanoscale Electronic Materials and Devices Laboratory, Faculty of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa, 3200003, Israel
| | - Pranab K Mohapatra
- Department of Materials Science and Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv, 6997801, Israel
| | - Lital Dezanashvili
- Department of Materials Science and Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv, 6997801, Israel
| | - Ariel Ismach
- Department of Materials Science and Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv, 6997801, Israel
| | - Elad Koren
- Nanoscale Electronic Materials and Devices Laboratory, Faculty of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa, 3200003, Israel
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14
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Rong K, Wang B, Reuven A, Maguid E, Cohn B, Kleiner V, Katznelson S, Koren E, Hasman E. Photonic Rashba effect from quantum emitters mediated by a Berry-phase defective photonic crystal. Nat Nanotechnol 2020; 15:927-933. [PMID: 32839591 DOI: 10.1038/s41565-020-0758-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 07/27/2020] [Indexed: 06/11/2023]
Abstract
Heterostructures combining a thin layer of quantum emitters and planar nanostructures enable custom-tailored photoluminescence in an integrated fashion. Here, we demonstrate a photonic Rashba effect from valley excitons in a WSe2 monolayer, which is incorporated into a photonic crystal slab with geometric phase defects, that is, into a Berry-phase defective photonic crystal. This phenomenon of spin-split dispersion in momentum space arises from a coherent geometric phase pickup assisted by the Berry-phase defect mode. The valley excitons effectively interact with the defects for site-controlled excitation, photoluminescence enhancement and spin-dependent manipulation. Specifically, the spin-dependent branches of photoluminescence in momentum space originate from valley excitons with opposite helicities and evidence the valley separation at room temperature. To further demonstrate the versatility of the Berry-phase defective photonic crystals, we use this concept to separate opposite spin states of quantum dot emission. This spin-enabled manipulation of quantum emitters may enable highly efficient metasurfaces for customized planar sources with spin-polarized directional emission.
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Affiliation(s)
- Kexiu Rong
- Micro and Nanooptics Laboratory, Faculty of Mechanical Engineering and Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa, Israel
| | - Bo Wang
- Micro and Nanooptics Laboratory, Faculty of Mechanical Engineering and Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa, Israel
| | - Avi Reuven
- Micro and Nanooptics Laboratory, Faculty of Mechanical Engineering and Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa, Israel
| | - Elhanan Maguid
- Micro and Nanooptics Laboratory, Faculty of Mechanical Engineering and Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa, Israel
| | - Bar Cohn
- Micro and Nanooptics Laboratory, Faculty of Mechanical Engineering and Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa, Israel
| | - Vladimir Kleiner
- Micro and Nanooptics Laboratory, Faculty of Mechanical Engineering and Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa, Israel
| | - Shaul Katznelson
- Faculty of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Elad Koren
- Faculty of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Erez Hasman
- Micro and Nanooptics Laboratory, Faculty of Mechanical Engineering and Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa, Israel.
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15
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Dutta D, Oz A, Hod O, Koren E. The scaling laws of edge vs. bulk interlayer conduction in mesoscale twisted graphitic interfaces. Nat Commun 2020; 11:4746. [PMID: 32958749 PMCID: PMC7506013 DOI: 10.1038/s41467-020-18597-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 09/02/2020] [Indexed: 11/09/2022] Open
Abstract
The unusual electronic properties of edges in graphene-based systems originate from the pseudospinorial character of their electronic wavefunctions associated with their non-trivial topological structure. This is manifested by the appearance of pronounced zero-energy electronic states localized at the material zigzag edges that are expected to have a significant contribution to the interlayer transport in such systems. In this work, we utilize a unique experimental setup and electronic transport calculations to quantitatively distinguish between edge and bulk transport, showing that their relative contribution strongly depends on the angular stacking configuration and interlayer potential. Furthermore, we find that, despite of the strong localization of edge state around the circumference of the contact, edge transport in incommensurate interfaces can dominate up to contact diameters of the order of 2 μm, even in the presence of edge disorder. The intricate interplay between edge and bulk transport contributions revealed in the present study may have profound consequences on practical applications of nanoscale twisted graphene-based electronics.
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Affiliation(s)
- Debopriya Dutta
- Faculty of Materials Science and Engineering and the Russell Berrie Nanotechnology Institute, Technion - Israel Institute of Technology, 3200003, Haifa, Israel
| | - Annabelle Oz
- Department of Physical Chemistry, School of Chemistry, The Raymond and Beverly Sackler Faculty of Exact Sciences and The Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv, IL, 6997801, Israel
| | - Oded Hod
- Department of Physical Chemistry, School of Chemistry, The Raymond and Beverly Sackler Faculty of Exact Sciences and The Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv, IL, 6997801, Israel
| | - Elad Koren
- Faculty of Materials Science and Engineering and the Russell Berrie Nanotechnology Institute, Technion - Israel Institute of Technology, 3200003, Haifa, Israel.
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16
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Brill AR, Kuntumalla MK, de Ruiter G, Koren E. Formation of Highly Ordered Self-Assembled Monolayers on Two-Dimensional Materials via Noncovalent Functionalization. ACS Appl Mater Interfaces 2020; 12:33941-33949. [PMID: 32589020 DOI: 10.1021/acsami.0c09722] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Functionalized two-dimensional materials (2DMs) are attracting much attention due to their promising applications in nanoscale devices. Producing continuous and homogeneous surface assemblies with a high degree of order has been challenging. In this work, we demonstrate that by noncovalently self-assembling molecular platforms on 2DMs, high-quality and highly ordered monolayers can be generated. The high degree of order and uniformity of the self-assembled monolayer layers were confirmed by a variety of analytic techniques including time-of-flight secondary ion mass spectrometry, scanning tunnelling microscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. Furthermore, by selectively enhancing the molecular vibrations of the molecular platform, via a combination of graphene-enhanced Raman spectroscopy (GERS) and surface-enhanced Raman spectroscopy (SERS), we were able to determine the orientation of self-assembled molecular platforms with respect to the surface normal. The selective enhancement of the vibrational modes occurs by taking advantage of the distance dependence of the Raman enhancement either by the graphene surface (GERS) or the silver nanoparticules (SERS) that are located on top of the self-assembled monolayer.
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Affiliation(s)
- Adam R Brill
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Technion City, Haifa 3200008, Israel
- Faculty of Materials Science and Engineering, Israel Institute of Technology, Technion City, Haifa 3200008, Israel
| | - Mohan Kumar Kuntumalla
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Technion City, Haifa 3200008, Israel
| | - Graham de Ruiter
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Technion City, Haifa 3200008, Israel
| | - Elad Koren
- Faculty of Materials Science and Engineering, Israel Institute of Technology, Technion City, Haifa 3200008, Israel
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17
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Van Tiggelen H, LeBlanc K, Campbell K, Woo K, Baranoski S, Chang Y, Dunk A, Gloeckner M, Hevia H, Holloway S, Idensohn P, Karadağ A, Koren E, Kottner J, Langemo D, Ousey K, Pokorná A, Romanelli M, Santos V, Smet S, Tariq G, Van den Bussche K, Van Hecke A, Verhaeghe S, Vuagnat H, Williams A, Beeckman D. Standardizing the classification of skin tears: validity and reliability testing of the International Skin Tear Advisory Panel Classification System in 44 countries. Br J Dermatol 2020; 183:146-154. [PMID: 31605618 PMCID: PMC7384145 DOI: 10.1111/bjd.18604] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/06/2019] [Indexed: 01/21/2023]
Abstract
BACKGROUND Skin tears are acute wounds that are frequently misdiagnosed and under-reported. A standardized and globally adopted skin tear classification system with supporting evidence for diagnostic validity and reliability is required to allow assessment and reporting in a consistent way. OBJECTIVES To measure the validity and reliability of the International Skin Tear Advisory Panel (ISTAP) Classification System internationally. METHODS A multicountry study was set up to validate the content of the ISTAP Classification System through expert consultation in a two-round Delphi procedure involving 17 experts from 11 countries. An online survey including 24 skin tear photographs was conducted in a convenience sample of 1601 healthcare professionals from 44 countries to measure diagnostic accuracy, agreement, inter-rater reliability and intrarater reliability of the instrument. RESULTS A definition for the concept of a 'skin flap' in the area of skin tears was developed and added to the initial ISTAP Classification System consisting of three skin tear types. The overall agreement with the reference standard was 0·79 [95% confidence interval (CI) 0·79-0·80] and sensitivity ranged from 0·74 (95% CI 0·73-0·75) to 0·88 (95% CI 0·87-0·88). The inter-rater reliability was 0·57 (95% CI 0·57-0·57). The Cohen's Kappa measuring intrarater reliability was 0·74 (95% CI 0·73-0·75). CONCLUSIONS The ISTAP Classification System is supported by evidence for validity and reliability. The ISTAP Classification System should be used for systematic assessment and reporting of skin tears in clinical practice and research globally. What's already known about this topic? Skin tears are common acute wounds that are misdiagnosed and under-reported too often. A skin tear classification system is needed to standardize documentation and description for clinical practice, audit and research. What does this study add? The International Skin Tear Advisory Panel Classification System was psychometrically tested in 1601 healthcare professionals from 44 countries. Diagnostic accuracy was high when differentiating between type 1, 2 and 3 skin tears using a set of validated photographs.
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18
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Bessler R, Duerig U, Koren E. The dielectric constant of a bilayer graphene interface. Nanoscale Adv 2019; 1:1702-1706. [PMID: 36134207 PMCID: PMC9417051 DOI: 10.1039/c8na00350e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 03/07/2019] [Indexed: 05/30/2023]
Abstract
The interlayer relative dielectric constant, ε r, of 2-dimensional (2D) materials in general and graphitic materials in particular is one of their most important physical properties, especially for electronic applications. In this work, we study the electromechanical actuation of nano-scale graphitic contacts. We find that beside the adhesive forces there are capacitive forces that scale parabolically with the potential drop across the sheared interface. We use this phenomena to measure the intrinsic dielectric constant of the bilayer graphene interface i.e. ε r = 6 ± 2, which is in perfect agreement with recent theoretical predictions for multi-layer graphene structures. Our method can be generally used to extract the dielectric properties of 2D materials systems and interfaces and our results pave the way for utilizing graphitic and other 2D materials in electromechanical based applications.
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Affiliation(s)
- Ron Bessler
- Department of Materials Science and Engineering, The Russell Berrie Nanotechnology Institute, Technion - Israel Institute of Technology 3200003 Haifa Israel
| | - Urs Duerig
- SwissLitho AG Technopark 8005 Zurich Switzerland
| | - Elad Koren
- Department of Materials Science and Engineering, The Russell Berrie Nanotechnology Institute, Technion - Israel Institute of Technology 3200003 Haifa Israel
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19
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Fuchs Y, Yosefzon Y, Soteriou D, Kostic L, Koren E, Sedov E, Glaser F. SPOT-002 Caspase-3 regulates YAP-dependent organ size and tumour development. ESMO Open 2018. [DOI: 10.1136/esmoopen-2018-eacr25.36] [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: 11/04/2022] Open
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20
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Koren E, Leven I, Lörtscher E, Knoll A, Hod O, Duerig U. Coherent commensurate electronic states at the interface between misoriented graphene layers. Nat Nanotechnol 2016; 11:752-7. [PMID: 27271963 DOI: 10.1038/nnano.2016.85] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 04/26/2016] [Indexed: 05/13/2023]
Abstract
Graphene and layered materials in general exhibit rich physics and application potential owing to their exceptional electronic properties, which arise from the intricate π-orbital coupling and the symmetry breaking in twisted bilayer systems. Here, we report room-temperature experiments to study electrical transport across a bilayer graphene interface with a well-defined rotation angle between the layers that is controllable in situ. This twisted interface is artificially created in mesoscopic pillars made of highly oriented pyrolytic graphite by mechanical actuation. The overall measured angular dependence of the conductivity is consistent with a phonon-assisted transport mechanism that preserves the electron momentum of conduction electrons passing the interface. The most intriguing observations are sharp conductivity peaks at interlayer rotation angles of 21.8° and 38.2°. These angles correspond to a commensurate crystalline superstructure leading to a coherent two-dimensional (2D) electronic interface state. Such states, predicted by theory, form the basis for a new class of 2D weakly coupled bilayer systems with hitherto unexplored properties and applications.
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Affiliation(s)
- Elad Koren
- IBM Research - Zurich, Rueschlikon 8803, Switzerland
| | - Itai Leven
- Department of Physical Chemistry, School of Chemistry, The Raymond and Beverly Sackler Faculty of Exact Sciences and The Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv 6997801, Israel
| | | | - Armin Knoll
- IBM Research - Zurich, Rueschlikon 8803, Switzerland
| | - Oded Hod
- Department of Physical Chemistry, School of Chemistry, The Raymond and Beverly Sackler Faculty of Exact Sciences and The Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Urs Duerig
- IBM Research - Zurich, Rueschlikon 8803, Switzerland
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21
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Moallem E, Koren E, Ulmansky R, Pizov G, Barlev M, Barenholz Y, Naparstek Y. A liposomal steroid nano-drug for treating systemic lupus erythematosus. Lupus 2016; 25:1209-16. [DOI: 10.1177/0961203316636468] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 02/01/2016] [Indexed: 11/16/2022]
Abstract
Background Glucocorticoids have been known for years to be the most effective therapy in systemic lupus erythematosus. Their use, however, is limited by the need for high doses due to their unfavorable pharmacokinetics and biodistribution. We have previously developed a novel liposome-based steroidal (methylprednisolone hemisuccinate (MPS)) nano-drug and demonstrated its specific accumulation in inflamed tissues, as well as its superior therapeutic efficacy over that of free glucocorticoids (non-liposomal) in the autoimmune diseases, including the adjuvant arthritis rat model and the experimental autoimmune encephalomyelitis mouse model. Objectives In the present work we have evaluated the therapeutic effect of the above liposome-based steroidal (MPS) nano-drug in the MRL-lpr/lpr murine model of SLE and compared it with similar doses of the free MPS. Methods MRL-lpr/lpr mice were treated with daily injections of free MPS or weekly injections of 10% dextrose, empty nano-liposomes or the steroidal nano-drug and the course of their disease was followed up to the age of 24 weeks. Results Treatment with the steroidal nano-drug was found to be significantly superior to the free MPS in suppressing anti-dsDNA antibody levels, proliferation of lymphoid tissue and renal damage, and in prolonging survival of animals. Conclusion This significant superiority of our liposome based steroidal nano-drug administered weekly compared with daily injections of free methylprednisolone hemisuccinate in suppressing murine lupus indicates this glucocorticoid nano-drug formulation may be a good candidate for the treatment of human SLE.
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Affiliation(s)
- E Moallem
- Department of Medicine-Hadassah University Hospital, Jerusalem, Israel
| | - E Koren
- The Laboratory of Membrane and Liposome Research, Department of Biochemistry, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - R Ulmansky
- Department of Medicine-Hadassah University Hospital, Jerusalem, Israel
| | - G Pizov
- Department of Medicine-Hadassah University Hospital, Jerusalem, Israel
| | - M Barlev
- The Laboratory of Membrane and Liposome Research, Department of Biochemistry, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Y Barenholz
- The Laboratory of Membrane and Liposome Research, Department of Biochemistry, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Y Naparstek
- Department of Medicine-Hadassah University Hospital, Jerusalem, Israel
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22
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23
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Koren E, Knoll AW, Lörtscher E, Duerig U. Direct experimental observation of stacking fault scattering in highly oriented pyrolytic graphite meso-structures. Nat Commun 2014; 5:5837. [PMID: 25510583 DOI: 10.1038/ncomms6837] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 11/11/2014] [Indexed: 11/09/2022] Open
Abstract
Stacking fault defects are thought to be the root cause for many of the anomalous transport phenomena seen in high-quality graphite samples. In stark contrast to their importance, direct observation of stacking faults by diffractive techniques has remained elusive due to fundamental experimental difficulties. Here we show that the stacking fault density and resistance can be measured by analyzing the non-Gaussian scatter observed in the c-axis resistivity of mesoscopic graphite structures. We also show that the deviation from Ohmic conduction seen at high electrical field strength can be fit to a thermally activated transport model, which accurately reproduces the stacking fault density inferred from the statistical analysis. From our measurements, we conclude that the c-axis resistivity is entirely determined by the stacking fault resistance, which is orders of magnitude larger than the inter-layer resistance expected from a Drude model.
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Affiliation(s)
- E Koren
- IBM Research-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - A W Knoll
- IBM Research-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - E Lörtscher
- IBM Research-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - U Duerig
- IBM Research-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
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24
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Andriyanov A, Koren E, Ahmed M, Barenholtz Y, Goldberg S. Combined radiofrequency (RF) ablation with nanodrug delivered doxorubicin: effect of liposome composition and ablation strategy on drug delivery and survival in an animal model. J Vasc Interv Radiol 2013. [DOI: 10.1016/j.jvir.2013.01.102] [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: 11/29/2022] Open
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25
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Koren E, Kupriyanova T. 1641 – Family burden-focused psychosocial therapy with parents and social functioning of children and adolescents with schizophrenic spectrum disorders. Eur Psychiatry 2013. [DOI: 10.1016/s0924-9338(13)76632-x] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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26
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Affiliation(s)
- I Ginsburg
- The Faculty of Dental Medicine, Institute for Dental Sciences, Hebrew University, Hadassah Medical Center, PO Box 12065, Jerusalem, 91120, Israel.
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27
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Koren E, Elias G, Boag A, Hemesath ER, Lauhon LJ, Rosenwaks Y. Direct measurement of individual deep traps in single silicon nanowires. Nano Lett 2011; 11:2499-2502. [PMID: 21591656 DOI: 10.1021/nl201019b] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The potential of the metal nanocatalyst to contaminate vapor-liquid-solid (VLS) grown semiconductor nanowires has been a long-standing concern, since the most common catalyst material, Au, is known to induce deep gap states in several semiconductors. Here we use Kelvin probe force microscopy to image individual deep acceptor type trapping centers in single undoped Si nanowires grown with an Au catalyst. The switching between occupied and empty trap states is reversibly controlled by the back-gate potential in a nanowire transistor. The trap energy level, i.e., E(C) - E(T) = 0.65 ± 0.1 eV was extracted and the concentration was estimated to be ∼2 × 10(16) cm(-3). The energy and concentration are consistent with traps resulting from the unintentional incorporation of Au atoms during the VLS growth.
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Affiliation(s)
- E Koren
- Department of Physical Electronics, School of Electrical Engineering, Tel-Aviv University, Tel-Aviv 69978, Israel
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Koren E, Hyun JK, Givan U, Hemesath ER, Lauhon LJ, Rosenwaks Y. Obtaining uniform dopant distributions in VLS-grown Si nanowires. Nano Lett 2011; 11:183-187. [PMID: 21126102 DOI: 10.1021/nl103363c] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Semiconducting nanowires grown by the vapor-liquid-solid method commonly develop nonuniform doping profiles both along the growth axis and radially due to unintentional surface doping and diffusion of the dopants from the nanowire surface to core during synthesis. We demonstrate two approaches to mitigate nonuniform doping in phosphorus-doped Si nanowires grown by the vapor-liquid-solid process. First, the growth conditions can be modified to suppress active surface doping. Second, thermal annealing following growth can be used to produce more uniform doping profiles. Kelvin probe force microscopy and scanning photocurrent microscopy were used to measure the radial and the longitudinal active dopant distribution, respectively. Doping concentration variations were reduced by 2 orders of magnitude in both annealed nanowires and those for which surface doping was suppressed.
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Affiliation(s)
- E Koren
- Department of Physical Electronics, School of Electrical Engineering, Tel-Aviv University, Tel-Aviv, Israel
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29
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Koren E. The place for emotions in professional carers' thinking: reflections on two cases. Med Law 2010; 29:537-546. [PMID: 22145549] [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] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
How do carers know what is right for their patient? What can they do further to relying on the two pillars of knowledge and ethics? Knowledge foregrounds rational decision-making based on scientific evidence. It allows cost-benefit rationalization and the choice of the best feasible objective. The steady advance of medical science drives responsible carers to keep their knowledge and skills up-to-date. Bioethics grants primary attention to the prevention of causing harm in general, to pursuant of patients' subjective wellbeing and to allow the latter enjoy their autonomy and to guarantee them the sense of justice. There are, however, cases where these values collide and any care decision violates one principle or another. How are carers expected to act then? This article concerns the choices made by carers, as presented and discussed in two cases. These cases deal with a clash between two principles: parenthood vs. fertility, religious rite vs. social affiliation. This class has generated an ethical dilemma. In each case carers try to justify their choices by expert knowledge and other ethical values, but later reflection reveals that the predominant element in 'solving' these dilemmas was "emotions." Professional training submits that: 'Set aside feelings in order to keep your thinking 'straight.' However, reality proves this simply infeasible. The more complex the medical-ethical situation, it is more likely that "emotions" take over. We have no choice as responsible carers but to allow our emotions the status of a factor of influence in their own right. Nowadays, a basic medical training for doctors and nurses offers an integrated body of knowledge and therapeutic skills. In addition, trainees are introduced to bioethics, supposedly sufficient to guide their future steps in their chosen profession. But how does this training in fact shape their future ethical conduct, if at all? How does it affect their ability to maintain ethical responsibility throughout therapeutic interactions? Perhaps there are other factors which govern the individual's conduct and his/her ethical responsibility? Simulation exercises were conducted, designed to induce healthcare professionals to reflect on the ethics of their own decision-making. The results demonstrated that therapeutic skills and familiarity with bioethical principles are not the sole factors governing the individual's ethical conduct. It turns out that emotions and feelings play a key part; this at once raises the question as to whether a medical training for doctors and nurses, in its current format, concerns itself with emotions and with how emotions shape a therapeutic personality. If not, then our training designers have food for thought. How can such training make trainees more aware of the power of their emotions? And, what are the ramifications on daily practice concerning ethical responsibility? Another question concerns the possible proper methods for mastering the theoretical materials and the practical techniques that promote emotional self-development?
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Affiliation(s)
- E Koren
- Nursing Division, The Israeli Ministry of Health, Jerusalem.
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Abstract
We have measured the radial distribution and diffusion of active dopant atoms in individual silicon nanowires grown by the vapor-liquid-solid (VLS) method. Our method is based on successive surface etching of a portion of a contacted nanowire, followed by measurement of the potential difference between the etched and unetched areas using Kelvin probe force microscopy (KPFM). The radial dopant distribution is obtained by fitting the measured potentials with a three-dimensional solution of Poisson equation. We find that the radial active dopant distribution decreases by almost 2 orders of magnitude from the wire surface to its core even when there is no indication for tapering. In addition, the dopant profile is consistent with a very large diffusion coefficient of D approximately 1 x 10(-19) m(2) s(-1). This implies that phosphorus (P) diffusion during the VLS growth is remarkably high and subsequent thermal annealing must be used when a homogeneous dopant distribution is required.
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Affiliation(s)
- Elad Koren
- School of Electrical Engineering, Tel-Aviv University, Tel-Aviv, Israel
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31
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Koren E, Lipkin J, Klar A, Hershkovitz E, Ginsburg I, Kohen R. Total oxidant-scavenging capacities of plasma from glycogen storage disease type Ia patients as measured by cyclic voltammetry, FRAP and luminescence techniques. J Inherit Metab Dis 2009; 32:651. [PMID: 19728140 DOI: 10.1007/s10545-009-1242-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Revised: 07/09/2009] [Accepted: 07/13/2009] [Indexed: 12/14/2022]
Abstract
It has been suggested that the very low incidence of atherosclerosis in glycogen storage disease type Ia (GSD Ia) subjects might be attributed to elevated levels of uric acid, one of the potent low molecular- weight antioxidants found in plasma. The present communication describes a use of two analytical methods-cyclic voltammetry and ferric reducing ability of plasma-and also two chemiluminescence methods to evaluate the total oxidant-scavenging capacities (TOSC) of plasma from GSD Ia patients. Our results verified the elevation of TOSC in GSD Ia patients and we propose the inclusion of luminescence and cyclic voltammetry assays as reliable methods for estimating TOSC in a variety of clinical disorders. Our findings with the cyclic voltammetry method add support to the assumption that the elevated uric acid levels might be the main contributor to plasma antioxidant capacity and possible protection against atherosclerosis.
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Affiliation(s)
- E Koren
- Department of Pharmaceutics, School of Pharmacy, Richard and Jean Zarbin Chair in Medical Studies, Hebrew University, Hadassah Faculty of Medicine, Jerusalem, 91120, Israel
| | - J Lipkin
- Department of Pediatrics, Bikur Cholim General Hospital, Jerusalem, Israel
| | - A Klar
- Department of Pediatrics, Bikur Cholim General Hospital, Jerusalem, Israel
| | - E Hershkovitz
- Pediatric Endocrinology & Metabolic Unit, Soroka Medical University Center, Beer Sheva, Israel
| | - I Ginsburg
- Faculty of Dental Medicine, Institute for Dental Sciences, Hebrew University, Hadassah Medical Center, Jerusalem, Israel
| | - R Kohen
- Department of Pharmaceutics, School of Pharmacy, Richard and Jean Zarbin Chair in Medical Studies, Hebrew University, Hadassah Faculty of Medicine, Jerusalem, 91120, Israel.
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Ginsburg I, Koren E, Horani A, Mahamid M, Doron S, Muhanna N, Amer J, Safadi R. Amelioration of hepatic fibrosis via Padma Hepaten is associated with altered natural killer T lymphocytes. Clin Exp Immunol 2009; 157:155-64. [PMID: 19659781 DOI: 10.1111/j.1365-2249.2009.03936.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Hepatic fibrosis is the end-stage consequence of chronic liver disease, affecting many people worldwide. Unlike the anti-fibrotic effect of natural killer (NK) cells, CD8 and NK T subsets are considered as profibrogenic subsets. Padma Hepaten is a multi-compound herbal preparation derived from Tibetan medicine and has proven efficacy in some clinical trials and tests at the cellular level. In this study, we evaluate the immune efficacy of Padma Hepaten administered intraperitoneally (i.p.) and/or orally in a mice model of hepatic fibrosis. Hepatic fibrosis was induced by 6 weeks of biweekly i.p. carbon tetrachloride (CCl4) injections in male C57Bl6 mice. There were four groups, including naive mice, non-treated fibrotic mice and fibrotic mice treated by Padma Hepaten at weeks 5-6 of fibrosis induction either orally or by i.p. injections. Padma Hepaten was prepared at 10 mg/ml in saline and 250 microl (2.5 mg) were administered four times per week. After week 6, animals were killed. To isolate a Padma Hepaten-associated effect on lymphocytes, splenocytes were harvested from either naive or Padma Hepaten-treated non-fibrotic donors. Isolated splenocytes were therefore reconstituted into two groups of irradiated recipients. Recipients were then administered the same CCl4 regimen. Hepatic fibrosis was determined by sirius red staining of liver sections and by assessment of alpha smooth muscle actin expression compared with beta-actin (both by mRNA as well as the protein liver extract western blotting). Hepatic fibrosis and alanine aminotransferase serum levels were decreased significantly in both Padma Hepaten-treated groups compared with the non-treated fibrotic group. Padma Hepaten treatment was associated with attenuation of lymphocyte subsets in both treated groups. Using a chemiluminescence technique to assess total anti-oxidant capacities (TAC), it was found that both the plasmas and livers of mice treated by CCl4 had significantly higher TAC compared with controls. However, the levels of TAC in animals treated either by CCl4 alone or CCl4 with Padma Hepaten were similar. Adoptive transfer of Padma Hepaten-treated lymphocytes was associated with fibrosis amelioration compared with recipients with naive lymphocytes. CCl4 generates higher levels of anti-oxidant capacities, probably as a response to oxidative stress. Padma Hepaten administration attenuated hepatic fibrogenesis significantly, accompanied by attenuation of lymphocyte but not anti-oxidant capacities.
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Affiliation(s)
- I Ginsburg
- Institute of Dental Research, Faculty of Dental Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
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Abstract
Enhanced light to electric power conversion efficiency of photovoltaic cells with a low absorbance was achieved using waveguide integration. We present a proof of concept using a very thin dye-sensitized solar cell which absorbed only a small fraction of the light at normal incidence. The glass substrate in conjunction with the solar cells reflecting back contact formed a planar waveguide, which lead to more than four times higher conversion efficiency compared to conventional illumination at normal incidence. This illumination concept leads to a new type of multi-junction PV systems based on enforced spectral splitting along the waveguide.
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Affiliation(s)
- Sven Rühle
- Department of Chemistry, Bar Ilan University, Ramat Gan, 52900, Israel.
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Koren E, Mytych D, Koscec M, Ferbas J, Gupta S, Moxness M, Swanson S. Strategies for the preclinical and clinical characterization of immunogenicity. Dev Biol (Basel) 2005; 122:195-200. [PMID: 16375262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Affiliation(s)
- E Koren
- Department of Clinical Immunology, Amgen Inc, Thousand Oaks, California 91320, USA.
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35
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Koren E. From characterization of antibodies to prediction of immunogenicity. Dev Biol (Basel) 2003; 109:87-95. [PMID: 12434917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Affiliation(s)
- E Koren
- Bioanalytical Research and Development, Genentech, Inc, South San Francisco, CA, USA
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36
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Abstract
There is a large and increasing number of therapeutic proteins approved for clinical use and many more undergoing preclinical studies and clinical trials in humans. Most of them are human or 'humanized' recombinant molecules. Virtually all therapeutic proteins elicit some level of antibody response, which in some cases, can lead to potentially serious side effects. Therefore, immunogenicity of therapeutic proteins is a concern for clinicians, manufacturers and regulatory agencies. In order to assess immunogenicity of these molecules, appropriate detection, quantitation and characterization of antibody responses are necessary. Immune responses to therapeutic proteins in conventional animal models has not been, except in rare cases, predictive of the response in humans. In recent years there has been a considerable progress in development of computational methods for prediction of epitopes in protein molecules that have the potential to induce an immune response in a recipient. Initial attempts to apply such tools in early development of therapeutic proteins have already been reported. It is expected that computer driven prediction followed by in vitro and/or in vivo testing of any potentially immunogenic epitopes will help in avoiding, or at least minimizing, immune responses to therapeutic proteins.
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37
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Koren E. Lasting armed conflict in Chechnaya and mental health of children. Eur Psychiatry 2002. [DOI: 10.1016/s0924-9338(02)80516-8] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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38
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Abstract
Thyroid hormone deficient osteoblastic cells in cell culture released a significantly higher amount of alkaline phosphate (ALP) activity following T3 replacement. T3 increased the release of total and membrane-bound ALP activity in these cells significantly more than T4 or inactive thyroid hormone metabolite, DIT. The effect of T3 on the membrane-bound ALP fraction was dose and time dependent; higher concentrations of T3 and longer incubation time with T3 proportionally increased the enzyme activity. T3 had no effect on the release of soluble fraction of ALP. Our results indicate that in "hypothyroid" osteoblastic cells the total release of ALP is decreased and that the secreted fraction of ALP is predominantly in soluble form, whereas the addition of T3 stimulates ALP release and mainly increases the membrane-bound fraction. T3 also increased formation of actin cytoskeleton in hypothyroid osteoblastic cells. Cytochalasin treatment, through its inhibition of actin polymerization, produced a significant decrease of membrane-bound ALP release induced by T3. These data suggest that the regulatory role of T3 in skeletal development can partly be due to its stimulatory effect on the release of membrane-bound ALP by osteoblastic cells which is thought to be an important factor in the initiation of biological calcification.
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Affiliation(s)
- K Banovac
- Department of Orthopaedics and Rehabilitation, University of Miami School of Medicine, Florida, USA
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39
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Koren E. P01.114 Mental health and modern armed conflict in the chechen republic. Eur Psychiatry 2000. [DOI: 10.1016/s0924-9338(00)94520-6] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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40
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Neethling FA, Koscec M, Oriol R, Cooper DK, Koren E. A reliable, rapid and inexpensive two-color fluorescence assay to monitor serum cytotoxicity in xenotransplantation. J Immunol Methods 1999; 222:31-44. [PMID: 10022370 DOI: 10.1016/s0022-1759(98)00175-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Removal and/or neutralization of preformed anti-pig antibodies in non-human primate blood have been shown to prevent the hyperacute rejection of transplanted pig organs. The purpose of this study was to establish a suitable in vitro method that would allow for screening and comparison of various agents and methods potentially useful in the prevention of hyperacute rejection. The pig kidney cell line (PK15), pig aortic endothelial cell line (AG08472), and a primary culture of endothelial cells explanted from a pig aorta were incubated with either human or baboon sera. Complement-dependent cytotoxic activity of human and baboon sera was determined on all three types of pig cells using a two-color fluorescence assay and compared with the conventional 51Chromium (51Cr)-release assay. The assay was also performed on PK15 cells as a 2-chambered slide assay and compared with a microcytotoxicity assay performed in Terasaki trays. Using the microcytotoxicity assay, a 1-step assay utilizing endogenous complement was compared with a 2-step assay where rabbit complement was added. Of the three types of cells studied, PK15 cells were the most sensitive to cytotoxic injury, followed by AG cells and the primary endothelial culture. Good correlation between the 51Cr-release and the two-color fluorescence method was documented. There was good agreement between the results obtained using the 2-chambered slide method and the microcytotoxicity assay, as there was between the 1- and the 2-step assays. The 1- and 2-step assays provided information on the level and efficacy of endogenous complement. We conclude that the two-color fluorescence assay is suitable for the rapid and inexpensive screening of therapeutic interventions that might be useful in the prevention of hyperacute xenograft rejection, and that PK15 cells are suitable for use in this assay.
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Affiliation(s)
- F A Neethling
- Oklahoma Transplantation Institute, Integris Baptist Medical Center, Oklahoma City, USA
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41
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Koren W, Koren E, Nacasch N, Ehrenfeld M, Gur H. Rhabdomyolysis associated with clozapine treatment in a patient with decreased calcium-dependent potassium permeability of cell membranes. Clin Neuropharmacol 1998; 21:262-4. [PMID: 9704170] [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: 02/08/2023]
Abstract
A 21-year-old patient developed rhabdomyolysis during his nineteenth week of treatment with clozapine for drug-resistant schizophrenia. No risk factors for rhabdomyolysis were found, but the calcium-dependent potassium efflux, normally responsible for membrane hyperpolarization and muscle refractoriness, was severely decreased in the patient's red blood cells. Clozapine is speculated to cause rhabdomyolysis in patients with defective calcium-activated K+ channels.
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Affiliation(s)
- W Koren
- Department of Medicine, Chaim Sheba Medical Center, Tel-Hashomer, Israel
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42
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Koscec M, Koren E, Wolfson-Reichlin M, Fugate RD, Trieu E, Targoff IN, Reichlin M. Autoantibodies to ribosomal P proteins penetrate into live hepatocytes and cause cellular dysfunction in culture. The Journal of Immunology 1997. [DOI: 10.4049/jimmunol.159.4.2033] [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] [Indexed: 01/02/2023]
Abstract
Abstract
Abs to ribosomal P protein have been shown to bind a membrane form of the P0 38-kDa ribosomal phosphoprotein. This study shows that after affinity-purified Abs to ribosomal P proteins bind living HepG2 cells, they then penetrate these live cells and cause cellular dysfunction. Binding and penetration of anti-P Abs is the property of F(ab')2 fragments as well as whole IgG molecules showing that neither binding nor penetration depends on Fc fragments or their cognate receptors. Confocal microscopy shows that internalized Ab concentrates in perinuclear vesicles (presumably lysosomes), but substantial quantities of Ab are also found in the cytosol. This intracellular Ab adversely affects the synthesis of apolipoprotein B resulting in a threefold increase in cellular cholesterol with lipid droplet accumulation as seen in some chronic liver diseases. It also has a profound inhibitory effect on global protein synthesis as measured by [35S]methionine incorporation. These studies therefore describe a model of cellular injury effected by specific Ab to ribosomal "P" protein that may underlie certain forms of autoimmune hepatic diseases.
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Affiliation(s)
- M Koscec
- Arthritis/Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City 73104, USA
| | - E Koren
- Arthritis/Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City 73104, USA
| | - M Wolfson-Reichlin
- Arthritis/Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City 73104, USA
| | - R D Fugate
- Arthritis/Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City 73104, USA
| | - E Trieu
- Arthritis/Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City 73104, USA
| | - I N Targoff
- Arthritis/Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City 73104, USA
| | - M Reichlin
- Arthritis/Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City 73104, USA
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43
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Koscec M, Koren E, Wolfson-Reichlin M, Fugate RD, Trieu E, Targoff IN, Reichlin M. Autoantibodies to ribosomal P proteins penetrate into live hepatocytes and cause cellular dysfunction in culture. J Immunol 1997; 159:2033-41. [PMID: 9257871] [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] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Abs to ribosomal P protein have been shown to bind a membrane form of the P0 38-kDa ribosomal phosphoprotein. This study shows that after affinity-purified Abs to ribosomal P proteins bind living HepG2 cells, they then penetrate these live cells and cause cellular dysfunction. Binding and penetration of anti-P Abs is the property of F(ab')2 fragments as well as whole IgG molecules showing that neither binding nor penetration depends on Fc fragments or their cognate receptors. Confocal microscopy shows that internalized Ab concentrates in perinuclear vesicles (presumably lysosomes), but substantial quantities of Ab are also found in the cytosol. This intracellular Ab adversely affects the synthesis of apolipoprotein B resulting in a threefold increase in cellular cholesterol with lipid droplet accumulation as seen in some chronic liver diseases. It also has a profound inhibitory effect on global protein synthesis as measured by [35S]methionine incorporation. These studies therefore describe a model of cellular injury effected by specific Ab to ribosomal "P" protein that may underlie certain forms of autoimmune hepatic diseases.
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Affiliation(s)
- M Koscec
- Arthritis/Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City 73104, USA
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44
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Koren W, Koren E, Sidi Y. [Does the effort syndrome have a right to be?]. Harefuah 1997; 132:293-5. [PMID: 9153903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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45
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Koren E, Milotic F, Neethling FA, Cooper DKC. Neutralization of the Cytotoxic Effect of Anti-αGal Antibodies with Monoclonal Anti-idiotypic Antibodies. Xenotransplantation 1997. [DOI: 10.1007/978-3-642-60572-7_27] [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: 10/17/2022]
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46
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Taniguchi S, Neethling FA, Korchagina EY, Bovin N, Ye Y, Kobayashi T, Niekrasz M, Li S, Koren E, Oriol R, Cooper DK. In vivo immunoadsorption of antipig antibodies in baboons using a specific Gal(alpha)1-3Gal column. Transplantation 1996; 62:1379-84. [PMID: 8958260 DOI: 10.1097/00007890-199611270-00001] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The major role of anti-alphaGal antibodies in the hyperacute rejection of pig organs by humans and baboons has been clearly demonstrated. Spacered alpha-galactose disaccharide (Gal(alpha1)-3Gal) hapten was produced by chemical synthesis and covalently attached to a flexible, hydrophilic polymer (PAA), which in turn was covalently coupled to macroporous glass beads, forming an immunoadsorbent that is mechanically and chemically stable and can be sterilized. The extracorporeal immunoadsorption (EIA) of anti-alphaGal antibodies using this column has been investigated in vivo in 3 baboons. In Baboon 1 (which had hyperacutely rejected a pig heart transplant 4 months previously, was not splenectomized, and did not receive any pharmacologic immunosuppression) the levels of anti-alphaGal antibody and antipig IgM and IgG, as well as serum cytotoxicity, fell significantly after each of 3 EIAs but were not eliminated. Serum cytotoxicity, antipig immunoglobulin and anti-alphaGal antibody rose steeply within 24 hr of the final EIA, suggesting that the return of cytotoxicity was associated with anti-alphaGa1 antibody. In Baboons 2 and 3 (which were immunologically naive and splenectomized, and received triple drug immunosuppressive therapy) serum cytotoxicity was totally eliminated and anti-alphaGal antibody and antipig IgM and IgG levels were greatly reduced by courses of EIA. In Baboon 2, cytotoxicity and all antibody levels remained negligible for approximately one week after the final (fourth) daily EIA. In Baboon 3, cytotoxicity and antibody levels were maintained low by intermittent EIA (over a period of 13 days) for almost 3 weeks, although antipig IgM began to rebound 4 days after the final EIA. We conclude that, in an immunosuppressed, splenectomized baboon, repeated EIA using a specific alphaGal disaccharide column will reduce antipig and anti-alphaGal antibody levels and serum cytotoxicity significantly for several days. This reduction in cytotoxicity will almost certainly be sufficient to delay the hyperacute rejection of a transplanted pig organ, but further studies are required to investigate whether it will be sufficient to allow accommodation to develop.
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Affiliation(s)
- S Taniguchi
- Oklahoma Transplantation Institute, Baptist Medical Center, Oklahoma City, USA
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47
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Li SF, Neethling FA, Taniguchi S, Yeh JC, Kobayashi T, Ye Y, Koren E, Cummings RD, Cooper DK. Glycans derived from porcine stomach mucin are effective inhibitors of natural anti-alpha-galactosyl antibodies in vitro and after intravenous infusion in baboons. Transplantation 1996; 62:1324-31. [PMID: 8932280 DOI: 10.1097/00007890-199611150-00026] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The current shortage of donor organs has stimulated investigation of pig-to-human xenotransplantation as a practical alternative to allotransplantation. However, a major obstacle to this xenotransplantation is hyperacute rejection, which is believed to be initiated by the interaction of natural anti-alpha-galactosyl (alphaGal) antibodies with alphaGal epitopes on pig vascular endothelium. Previously, we reported that neutral oligosaccharides derived from porcine stomach mucin (PSM) are effective inhibitors of human anti-alphaGal IgG in vitro. We now report that O-glycans derived from PSM by beta-elimination (PSMO) reduce the cytotoxicity of both baboon and human sera to pig kidney (PK15) cells in vitro. Crude PSM had some inhibitory effect in vitro, but PSMO were more than 100 times more potent. Moreover, 1 microg/ml of beta-eliminated PSMO that bound to an immunoaffinity column of anti-alphaGal antibodies were four times more efficient than total PSMO in protecting PK15 cells from the cytotoxic effect of baboon or human sera. Blood recovered from baboons after intravenous infusion of PMSO also showed significant protection of PK15 cells. We conclude that PSMO eluted from an anti-alphaGal immunoaffinity column demonstrate potent inhibitory effects against baboon and human serum cytotoxicity to PK15 cells in vitro and when administered intravenously. PSM may provide a cheap and readily available source of glycans that will be of therapeutic value in the prevention of hyperacute rejection.
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Affiliation(s)
- S F Li
- Oklahoma Transplantation Institute, Baptist Medical Center, Oklahoma City, USA
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48
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Koren E, Milotic F, Neethling FA, Koscec M, Fei D, Kobayashi T, Taniguchi S, Cooper DK. Monoclonal antiidiotypic antibodies neutralize cytotoxic effects of anti-alphaGal antibodies. Transplantation 1996; 62:837-43. [PMID: 8824486 DOI: 10.1097/00007890-199609270-00023] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The aims of this study were to produce and characterize mouse monoclonal antiidiotypic antibodies (AIAs) that specifically bind human antipig (anti-alphaGal) antibodies and to select those AIAs that neutralize the cytotoxicity of human or baboon serum to pig (PK15) cells. Mice were immunized with human anti-pig antibodies, and hybridomas were produced using conventional techniques. From a total of 480 clones, 11 produced AIAs that bound with high affinity to human anti-alpha Gal IgG and F(ab')2 fragments, and individually reduced serum cytotoxicity to pig cells by 40 - 90%. Seven of the AIAs also bound to human peripheral B lymphocytes (that express the same idiotypes as the antibodies produce). Several combinations of two or three AIAs provided 100% protection of PK15 cells. Selected AIAs injected intravenously into baboons reduced the cytotoxicity of subsequently drawn sera by 50--80% for >48 hr. The cytotoxicity studies also indicated that there are at least two dominant idiotypes expressed in the human anti-alphaGal population. We conclude that AIAs against anti-alphaGal antibodies could be successfully used in 1) preoperative characterization of a recipient's anti-alphaGal profile, (2) prevention of hyperacute rejection of a pig organ, and (3) specific immunosuppression through elimination of anti-alphaGal-producing B lymphocytes.
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Affiliation(s)
- E Koren
- Oklahoma Medical Research Foundation, Oklahoma City, USA
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Kobayashi T, Neethling F, Taniguchi S, Ye Y, Niekrasz M, Koren E, Hancock W, Takagi H, Cooper D. Investigation of the anti-complement agents, FUT-175 and K76COOH, in discordant xenotransplantation. Xenotransplantation 1996. [DOI: 10.1111/j.1399-3089.1996.tb00143.x] [Citation(s) in RCA: 16] [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: 11/24/2022]
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Taniguchi S, Neefhling F, Oriol R, Kobayashis T, Ye Y, Niekrasz M, Peters L, Kosanke S, Koren E, Cooper D. Ratites (ostrich, emu) as potential heart donors for humans: Immunologic, anatomic, and physiologic considerations. Xenotransplantation 1996. [DOI: 10.1111/j.1399-3089.1996.tb00145.x] [Citation(s) in RCA: 5] [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: 11/30/2022]
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