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Madenli O, Akarsu C, Adigüzel AO, Altuntepe A, Zan R, Deveci EÜ. Synthesis of graphite/rGO-modified fungal hyphae for chromium (VI) bioremediation process. Environ Technol 2024; 45:811-826. [PMID: 36152299 DOI: 10.1080/09593330.2022.2128892] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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: 06/10/2022] [Accepted: 09/02/2022] [Indexed: 06/16/2023]
Abstract
Bioremediation is a promising technology that can eliminate the drawbacks of conventional treatment methods in removing harmful toxic metals including chromium(VI). Therefore, in this study, fungal hyphae modified with graphite and reduced graphene oxide were synthesized and assessed for their potential to bioremediate heavy metals for the first time in the literature. The effects of the carbon-based materials on microbial structure were characterized using scanning electron microscopy analysis. Thermogravimetric, RAMAN, X-ray diffraction, and enzymatic analyzes were performed to determine the role of functional groups. In addition, batch adsorption experiments utilizing response surface methodology were conducted to optimize operating parameters such as time (1-11 h), chromium (10-50 mg/L), and graphite/reduced graphene oxide (0.1-1 g/L). The maximum adsorption capacity with the graphene fungal hyphae was determined to be 568 mg.g-1, which is 9.7 times that of the crude fungal hyphae. The Cr(VI) removal for fungal hyphae-graphite and fungal hyphae-reduced graphene oxide biocomposites was 98.25% and 98.49%, respectively. The isothermal and kinetic results perfectly matched the 2nd order pseudo-model and Langmuir model in terms of the nature of the adsorption process. The laboratory scale test results indicate that fungal hyphae modified with graphite and reduced graphene oxide have a high adsorption capacity, suitable for the removal of chromium (VI) from wastewater.
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Affiliation(s)
- Ozgecan Madenli
- Niğde Ömer Halisdemir University, Enviromental Engineering Deparment, Niğde, Turkey
| | - Ceyhun Akarsu
- Istanbul University-Cerrahpasa, Department of Environmental Engineering, Istanbul, Turkey
| | - Ali Osman Adigüzel
- Ondokuz Mayıs University, Moleculer Biology and Genetics, Samsun, Turkey
| | - Ali Altuntepe
- Niğde Ömer Halisdemir University, Nanotechnology Research Center, Niğde, Turkey
| | - Recep Zan
- Niğde Ömer Halisdemir University, Nanotechnology Research Center, Niğde, Turkey
- Niğde Ömer Halisdemir University, Faculty of Arts and Sciences Department, Niğde, Turkey
| | - Ece Ümmü Deveci
- Niğde Ömer Halisdemir University, Enviromental Engineering Deparment, Niğde, Turkey
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Zan R, Topcuoglu HS, Hubbezoglu I, Gorler O, Altunbas D, Ayhan M. Effect of different irrigation activation methods on non-infected dentinal tubule penetration of medicaments: A CLSM study. Niger J Clin Pract 2022; 25:895-902. [DOI: 10.4103/njcp.njcp_1932_21] [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]
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Olgar M, Çiriş A, Tomakin M, Zan R. Impact of in/ex situ annealing and reaction temperature on structural, optical and electrical properties of SnS thin films. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.130631] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Muratçobanoğlu H, Gökçek ÖB, Mert RA, Zan R, Demirel S. The impact of reduced graphene oxide (rGO) supplementation on cattle manure anaerobic digestion: Focusing on process performance and microbial syntrophy. Biochem Eng J 2021. [DOI: 10.1016/j.bej.2021.108080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Latychevskaia T, Zan R, Morozov S, Novoselov KS. Symmetry of diffraction patterns of two-dimensional crystal structures. Ultramicroscopy 2021; 228:113336. [PMID: 34174662 DOI: 10.1016/j.ultramic.2021.113336] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/28/2021] [Accepted: 06/09/2021] [Indexed: 10/21/2022]
Abstract
Conventionally, theoretical considerations in electron microscopy employ the weak phase approximation (WPA), which is only valid for weak scattering atomic elements (C, B, N) but not for transition metal dichalcogenide (TMD) materials. This leads to many exciting phenomena being overlooked. The present theoretical study goes beyond the weak phase approximation and thus the obtained results can be applied for two-dimensional (2D) crystals made of weakly as well of strongly scattering atoms, including the TMD materials. We show that the symmetry of an electron diffraction pattern, characterized by the Friedel's pairs, is governed by the symmetry of the exit wave distribution. For an infinite periodic crystal, the exit wave is an infinite and periodic 2D distribution which can be assigned an exit wave unit cell. The latter is determined by both the chemical composition of the crystallographic unit cell and the distance between the atomic layers. For 2D crystals of identical atoms, such as graphene, the exit wave unit cell is symmetrical and, thus, a symmetrical diffraction pattern is expected. For TMD materials, the exit wave unit cell is not symmetrical and a non-symmetrical diffraction pattern is expected for both monolayer and bilayer. Conventionally asymmetry in diffraction patterns has been explained by presence of dynamical (multiple) scattering effects. Our study shows that the asymmetry of a diffraction pattern can be explained solely by the asymmetry of the exit wave unit cell. The exit wave unit cell can be asymmetrical even in kinematic (single) scattering model. Therefore, conclusions about dynamical (multiple) scattering effects in 2D materials cannot be made based solely on asymmetry of a diffraction pattern. We also show that for hexagonally arranged atoms the second-order diffraction peaks show perfectly symmetrical intensities independently on the symmetry of the exit wave unit cell distribution.
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Affiliation(s)
| | - Recep Zan
- Nanotechnology Application and Research Center, Niǧde Ömer Halisdemir University, 51240 Niǧde, Turkey
| | - Sergey Morozov
- Institute of Microelectronics Technology and High Purity Materials, Russian Academy of Sciences, Chernogolovka, Russia
| | - Kostya S Novoselov
- National Graphene Institute, University of Manchester, Oxford Road, Manchester, M13 9PL, UK; Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore; Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 117546, Singapore; Chongqing 2D Materials Institute, Liangjiang New Area, Chongqing, 400714, China
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Olgar M, Altuntepe A, Erkan S, Zan R. Fabrication of Cu-rich CZTS thin films by two-stage process: Effect of gas flow-rate in sulfurization process. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.129922] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Muratçobanoğlu H, Gökçek ÖB, Mert RA, Zan R, Demirel S. Simultaneous synergistic effects of graphite addition and co-digestion of food waste and cow manure: Biogas production and microbial community. Bioresour Technol 2020; 309:123365. [PMID: 32305850 DOI: 10.1016/j.biortech.2020.123365] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [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: 02/14/2020] [Revised: 04/07/2020] [Accepted: 04/08/2020] [Indexed: 06/11/2023]
Abstract
The effects of graphite on the anaerobic digestion of food waste (FW), cow manure (CM) and its mixture (FW/CM) via batch experiments under mesophilic conditions have been investigated in this study. Maximum biogas production with graphite addition for FW + 1 g/L, CM + 1.5 g/L and FW/CM + 0.75 g/L are 1128.46, 829.6 and 1471.1 mL/gVS respectively. Additionally, this study investigates the link between microbial community structure and biogas production when graphite addition of anaerobic digester was conducted. Based on 16S rRNA gene amplicon sequencing results, Aminiphilus (13-14%), Actinobaculum (13-15%) and Clostridium (12-18%) were the predominant bacterial genera in graphite-added FW, CM and FW/CM reactors, respectively. Comparatively higher biogas production of FW/CM synergistically affected by abundances of Clostridium as well as co-digestion in this anaerobic digestion setup. Methanosaeta was the most abundant methanogen in the graphite added digesters; however, the relative abundance of these genera was different.
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Affiliation(s)
- Hamdi Muratçobanoğlu
- Faculty of Engineering, Department of Environmental Engineering, Nigde Ömer Halisdemir University, Nigde, Turkey.
| | - Öznur Begüm Gökçek
- Faculty of Engineering, Department of Environmental Engineering, Nigde Ömer Halisdemir University, Nigde, Turkey
| | - Ruhullah Ali Mert
- Faculty of Engineering, Department of Environmental Engineering, Nigde Ömer Halisdemir University, Nigde, Turkey
| | - Recep Zan
- Nanotechnology Application and Research Center, Nigde Ömer Halisdemir University, Nigde, Turkey
| | - Sevgi Demirel
- Faculty of Engineering, Department of Environmental Engineering, Nigde Ömer Halisdemir University, Nigde, Turkey
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Ulgey M, Zan R, Gorler O, Yesilyurt G, Cotur F. Evaluating efficacy of different post materials and lengths on bonding strength between root canal dentin and post restorations: An experimental study. Niger J Clin Pract 2020; 23:950-956. [PMID: 32620724 DOI: 10.4103/njcp.njcp_481_19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Background During post restoration, different root structures require several types of posts to increase duration of their clinical use. Several materials have been investigated to enhance their quality and optimize their length according to the available root canal. Aims The aim of this study was to determine the effect of zirconia, fiber, and ceromer posts with 3- and 6-mm post sizes on the bonding strength of them to root canal dentinal wall with the means of pull-out bond strength test. Methods Forty-eight single-rooted mandibular human premolar teeth were collected and prepared for this in vitro study. With resin cement, 3- and 6-mm study posts including zirconia, fiber, and ceromer were luted to prepare teeth. For the retention testing, the pull-out force was applied to each specimen parallel to longitudinal axis of both the post and tooth. Results Both type of materials and size of posts changed the value of bonding strength. In all the post types, 6-mm ones performed better. Overall, the best bonding strength was obtained with fiber posts and the better bonding strength was obtained with zirconia; however, ceromer provided the least bonding strength. Conclusion Current experiments supported that 6-mm post size can increase the bonding between root canal dentin and studied posts. When considering post materials, fiber provided the best bonding strength in current laboratory setup. Second, zirconia had meaningfully acceptable bonding strength; however, the bonding strength of ceromer posts was not favorable. Further studies optimizing post fabrication techniques of root materials may increase the bonding strength of posts to human dentin to an acceptable clinical degree.
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Affiliation(s)
- M Ulgey
- Department of Prosthodontics, Faculty of Dentistry, Sivas Cumhuriyet University, Sivas, Turkey
| | - R Zan
- Department of Endodontics, Faculty of Dentistry, Sivas Cumhuriyet University, Sivas, Turkey
| | - O Gorler
- Department of Prosthodontics, Faculty of Dentistry, Sivas Cumhuriyet University, Sivas, Turkey
| | - G Yesilyurt
- Department of Prosthodontics, Faculty of Dentistry, Sivas Cumhuriyet University, Sivas, Turkey
| | - F Cotur
- Department of Endodontics, Faculty of Dentistry, Sivas Cumhuriyet University, Sivas, Turkey
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Ni J, Ling H, Zhang S, Wang Z, Peng Z, Benyshek C, Zan R, Miri A, Li Z, Zhang X, Lee J, Lee KJ, Kim HJ, Tebon P, Hoffman T, Dokmeci M, Ashammakhi N, Li X, Khademhosseini A. Three-dimensional printing of metals for biomedical applications. Mater Today Bio 2019; 3:100024. [PMID: 32159151 PMCID: PMC7061633 DOI: 10.1016/j.mtbio.2019.100024] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [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: 05/12/2019] [Revised: 08/08/2019] [Accepted: 08/12/2019] [Indexed: 12/21/2022] Open
Abstract
Three-dimensional (3D) printing technology has received great attention in the past decades in both academia and industry because of its advantages such as customized fabrication, low manufacturing cost, unprecedented capability for complex geometry, and short fabrication period. 3D printing of metals with controllable structures represents a state-of-the-art technology that enables the development of metallic implants for biomedical applications. This review discusses currently existing 3D printing techniques and their applications in developing metallic medical implants and devices. Perspective about the current challenges and future directions for development of this technology is also presented.
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Affiliation(s)
- J. Ni
- Department of Bioengineering, University of California-Los Angeles, Los Angeles, CA 90095, USA
- Center for Minimally Invasive Therapeutics (C-MIT), University of California-Los Angeles, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - H. Ling
- Center for Minimally Invasive Therapeutics (C-MIT), University of California-Los Angeles, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA
- Department of Mechanical and Aerospace Engineering, University of California-Los Angeles, Los Angeles, CA 90095, USA
| | - S. Zhang
- Department of Bioengineering, University of California-Los Angeles, Los Angeles, CA 90095, USA
- Center for Minimally Invasive Therapeutics (C-MIT), University of California-Los Angeles, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA
| | - Z. Wang
- Department of Bioengineering, University of California-Los Angeles, Los Angeles, CA 90095, USA
- Center for Minimally Invasive Therapeutics (C-MIT), University of California-Los Angeles, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA
| | - Z. Peng
- Department of Orthopaedic Surgery, Ningbo Medical Treatment Center Lihuili Hospital, PR China
| | - C. Benyshek
- Department of Bioengineering, University of California-Los Angeles, Los Angeles, CA 90095, USA
- Center for Minimally Invasive Therapeutics (C-MIT), University of California-Los Angeles, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA
| | - R. Zan
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - A.K. Miri
- Department of Bioengineering, University of California-Los Angeles, Los Angeles, CA 90095, USA
- Center for Minimally Invasive Therapeutics (C-MIT), University of California-Los Angeles, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA
| | - Z. Li
- Department of Bioengineering, University of California-Los Angeles, Los Angeles, CA 90095, USA
- Center for Minimally Invasive Therapeutics (C-MIT), University of California-Los Angeles, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA
- School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, 710049, China
| | - X. Zhang
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - J. Lee
- Department of Bioengineering, University of California-Los Angeles, Los Angeles, CA 90095, USA
- Center for Minimally Invasive Therapeutics (C-MIT), University of California-Los Angeles, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA
| | - K.-J. Lee
- Department of Bioengineering, University of California-Los Angeles, Los Angeles, CA 90095, USA
- Center for Minimally Invasive Therapeutics (C-MIT), University of California-Los Angeles, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA
| | - H.-J. Kim
- Department of Bioengineering, University of California-Los Angeles, Los Angeles, CA 90095, USA
- Center for Minimally Invasive Therapeutics (C-MIT), University of California-Los Angeles, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA
| | - P. Tebon
- Department of Bioengineering, University of California-Los Angeles, Los Angeles, CA 90095, USA
- Center for Minimally Invasive Therapeutics (C-MIT), University of California-Los Angeles, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA
| | - T. Hoffman
- Department of Bioengineering, University of California-Los Angeles, Los Angeles, CA 90095, USA
- Center for Minimally Invasive Therapeutics (C-MIT), University of California-Los Angeles, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA
| | - M.R. Dokmeci
- Department of Bioengineering, University of California-Los Angeles, Los Angeles, CA 90095, USA
- Center for Minimally Invasive Therapeutics (C-MIT), University of California-Los Angeles, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA
- Department of Radiology, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA 90095, USA
| | - N. Ashammakhi
- Department of Bioengineering, University of California-Los Angeles, Los Angeles, CA 90095, USA
- Center for Minimally Invasive Therapeutics (C-MIT), University of California-Los Angeles, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA
- Department of Radiology, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA 90095, USA
| | - X. Li
- Department of Mechanical and Aerospace Engineering, University of California-Los Angeles, Los Angeles, CA 90095, USA
- Department of Materials Science and Engineering, University of California-Los Angeles, Los Angeles, CA 90095, USA
| | - A. Khademhosseini
- Department of Bioengineering, University of California-Los Angeles, Los Angeles, CA 90095, USA
- Center for Minimally Invasive Therapeutics (C-MIT), University of California-Los Angeles, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA
- Department of Radiology, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA 90095, USA
- Department of Chemical and Biomolecular Engineering, University of California-Los Angeles, Los Angeles, CA 90095, USA
- Department of Bioindustrial Technologies, College of Animal Bioscience and Technology, Konkuk University, Seoul, Republic of Korea
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Hage FS, Hardcastle TP, Gjerding MN, Kepaptsoglou DM, Seabourne CR, Winther KT, Zan R, Amani JA, Hofsaess HC, Bangert U, Thygesen KS, Ramasse QM. Local Plasmon Engineering in Doped Graphene. ACS Nano 2018; 12:1837-1848. [PMID: 29369611 DOI: 10.1021/acsnano.7b08650] [Citation(s) in RCA: 8] [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: 06/07/2023]
Abstract
Single-atom B or N substitutional doping in single-layer suspended graphene, realized by low-energy ion implantation, is shown to induce a dampening or enhancement of the characteristic interband π plasmon of graphene through a high-resolution electron energy loss spectroscopy study using scanning transmission electron microscopy. A relative 16% decrease or 20% increase in the π plasmon quality factor is attributed to the presence of a single substitutional B or N atom dopant, respectively. This modification is in both cases shown to be relatively localized, with data suggesting the plasmonic response tailoring can no longer be detected within experimental uncertainties beyond a distance of approximately 1 nm from the dopant. Ab initio calculations confirm the trends observed experimentally. Our results directly confirm the possibility of tailoring the plasmonic properties of graphene in the ultraviolet waveband at the atomic scale, a crucial step in the quest for utilizing graphene's properties toward the development of plasmonic and optoelectronic devices operating at ultraviolet frequencies.
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Affiliation(s)
| | - Trevor P Hardcastle
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, U.K
- School of Chemical and Process Engineering, University of Leeds , Leeds LS2 9JT, U.K
| | - Morten N Gjerding
- CAMD and Center for Nanostructured Graphene (CNG), Technical University of Denmark , Fysikvej 1, Building 307, 2800 Kgs. Lyngby, Denmark
| | - Demie M Kepaptsoglou
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, U.K
- York NanoCentre, University of York , Heslington, York YO10 5BR, U.K
| | - Che R Seabourne
- School of Chemical and Process Engineering, University of Leeds , Leeds LS2 9JT, U.K
| | - Kirsten T Winther
- CAMD and Center for Nanostructured Graphene (CNG), Technical University of Denmark , Fysikvej 1, Building 307, 2800 Kgs. Lyngby, Denmark
| | - Recep Zan
- Nanotechnology Application and Research Center, Niğde Omer Halisdemir University , Niğde 51000, Turkey
| | - Julian Alexander Amani
- II Physikalisches Institut, Georg-August-Universität Göttingen , Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Hans C Hofsaess
- II Physikalisches Institut, Georg-August-Universität Göttingen , Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Ursel Bangert
- Bernal Institute and Department of Physics, University of Limerick , Limerick, Ireland
| | - Kristian S Thygesen
- CAMD and Center for Nanostructured Graphene (CNG), Technical University of Denmark , Fysikvej 1, Building 307, 2800 Kgs. Lyngby, Denmark
| | - Quentin M Ramasse
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, U.K
- School of Chemical and Process Engineering, University of Leeds , Leeds LS2 9JT, U.K
- School of Physics, University of Leeds , Leeds LS2 9JT, U.K
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Topçuoğlu HS, Zan R, Akpek F, Topçuoğlu G, Ulusan Ö, Aktı A, Düzgün S, Ağırnaslıgil M. Apically extruded debris during root canal preparation using Vortex Blue, K3XF, ProTaper Next and Reciproc instruments. Int Endod J 2015; 49:1183-1187. [DOI: 10.1111/iej.12572] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 11/02/2015] [Indexed: 11/28/2022]
Affiliation(s)
- H. S. Topçuoğlu
- Department of Endodontics; Faculty of Dentistry; Erciyes University; Kayseri Turkey
| | - R. Zan
- Department of Endodontics; Faculty of Dentistry; Cumhuriyet University; Sivas Turkey
| | - F. Akpek
- Department of Endodontics; Faculty of Dentistry; Erciyes University; Kayseri Turkey
| | - G. Topçuoğlu
- Department of Pedodontics; Faculty of Dentistry; Erciyes University; Kayseri Turkey
| | - Ö. Ulusan
- Department of Endodontics; Faculty of Dentistry; Erciyes University; Kayseri Turkey
| | - A. Aktı
- Department of Endodontics; Faculty of Dentistry; Erciyes University; Kayseri Turkey
| | - S. Düzgün
- Department of Endodontics; Faculty of Dentistry; Erciyes University; Kayseri Turkey
| | - M. Ağırnaslıgil
- Department of Endodontics; Faculty of Dentistry; Erciyes University; Kayseri Turkey
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Kepaptsoglou D, Hardcastle TP, Seabourne CR, Bangert U, Zan R, Amani JA, Hofsäss H, Nicholls RJ, Brydson RMD, Scott AJ, Ramasse QM. Electronic Structure Modification of Ion Implanted Graphene: The Spectroscopic Signatures of p- and n-Type Doping. ACS Nano 2015; 9:11398-11407. [PMID: 26446310 DOI: 10.1021/acsnano.5b05305] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A combination of scanning transmission electron microscopy, electron energy loss spectroscopy, and ab initio calculations is used to describe the electronic structure modifications incurred by free-standing graphene through two types of single-atom doping. The N K and C K electron energy loss transitions show the presence of π* bonding states, which are highly localized around the N dopant. In contrast, the B K transition of a single B dopant atom shows an unusual broad asymmetric peak which is the result of delocalized π* states away from the B dopant. The asymmetry of the B K toward higher energies is attributed to highly localized σ* antibonding states. These experimental observations are then interpreted as direct fingerprints of the expected p- and n-type behavior of graphene doped in this fashion, through careful comparison with density functional theory calculations.
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Affiliation(s)
- Demie Kepaptsoglou
- SuperSTEM Laboratory , SciTech Daresbury Campus, Daresbury WA4 4AD, United Kingdom
| | - Trevor P Hardcastle
- Institute for Materials Research, SCaPE, University of Leeds , Leeds LS2 9JT, United Kingdom
| | - Che R Seabourne
- Institute for Materials Research, SCaPE, University of Leeds , Leeds LS2 9JT, United Kingdom
| | - Ursel Bangert
- School of Materials, University of Manchester , Manchester M13 9PL, United Kingdom
| | - Recep Zan
- School of Materials, University of Manchester , Manchester M13 9PL, United Kingdom
| | - Julian Alexander Amani
- II. Physikalisches Institut, Georg-August-Universität Göttingen , Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Hans Hofsäss
- II. Physikalisches Institut, Georg-August-Universität Göttingen , Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Rebecca J Nicholls
- Deparment of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
| | - Rik M D Brydson
- Institute for Materials Research, SCaPE, University of Leeds , Leeds LS2 9JT, United Kingdom
| | - Andrew J Scott
- Institute for Materials Research, SCaPE, University of Leeds , Leeds LS2 9JT, United Kingdom
| | - Quentin M Ramasse
- SuperSTEM Laboratory , SciTech Daresbury Campus, Daresbury WA4 4AD, United Kingdom
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Kashtiban RJ, Dyson MA, Nair RR, Zan R, Wong SL, Ramasse Q, Geim AK, Bangert U, Sloan J. Atomically resolved imaging of highly ordered alternating fluorinated graphene. Nat Commun 2014; 5:4902. [DOI: 10.1038/ncomms5902] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2014] [Accepted: 08/01/2014] [Indexed: 11/09/2022] Open
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Susi T, Kotakoski J, Kepaptsoglou D, Mangler C, Lovejoy TC, Krivanek OL, Zan R, Bangert U, Ayala P, Meyer JC, Ramasse Q. Silicon-carbon bond inversions driven by 60-keV electrons in graphene. Phys Rev Lett 2014; 113:115501. [PMID: 25259987 DOI: 10.1103/physrevlett.113.115501] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Indexed: 05/08/2023]
Abstract
We demonstrate that 60-keV electron irradiation drives the diffusion of threefold-coordinated Si dopants in graphene by one lattice site at a time. First principles simulations reveal that each step is caused by an electron impact on a C atom next to the dopant. Although the atomic motion happens below our experimental time resolution, stochastic analysis of 38 such lattice jumps reveals a probability for their occurrence in a good agreement with the simulations. Conversions from three- to fourfold coordinated dopant structures and the subsequent reverse process are significantly less likely than the direct bond inversion. Our results thus provide a model of nondestructive and atomically precise structural modification and detection for two-dimensional materials.
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Affiliation(s)
- Toma Susi
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria
| | - Jani Kotakoski
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria and Department of Physics, University of Helsinki, P.O. Box 43, FI-00014 Helsinki, Finland
| | - Demie Kepaptsoglou
- SuperSTEM Laboratory, STFC Daresbury Campus, Daresbury WA4 4AD, United Kingdom
| | - Clemens Mangler
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria
| | | | | | - Recep Zan
- School of Materials, The University of Manchester, Manchester M13 9PL, United Kingdom and Department of Physics, Faculty of Arts and Sciences, Niğde University, 51000 Niğde, Turkey
| | - Ursel Bangert
- School of Materials, The University of Manchester, Manchester M13 9PL, United Kingdom and Department of Physics and Energy, University of Limerick, Limerick, Ireland
| | - Paola Ayala
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria
| | - Jannik C Meyer
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria
| | - Quentin Ramasse
- SuperSTEM Laboratory, STFC Daresbury Campus, Daresbury WA4 4AD, United Kingdom
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Zan R, Ramasse QM, Jalil R, Georgiou T, Bangert U, Novoselov KS. Control of radiation damage in MoS(2) by graphene encapsulation. ACS Nano 2013; 7:10167-74. [PMID: 24116975 DOI: 10.1021/nn4044035] [Citation(s) in RCA: 124] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Recent dramatic progress in studying various two-dimensional (2D) atomic crystals and their heterostructures calls for better and more detailed understanding of their crystallography, reconstruction, stacking order, etc. For this, direct imaging and identification of each and every atom is essential. Transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) are ideal and perhaps the only tools for such studies. However, the electron beam can in some cases induce dramatic structure changes, and radiation damage becomes an obstacle in obtaining the desired information in imaging and chemical analysis in the (S)TEM. This is the case of 2D materials such as molybdenum disulfide MoS2, but also of many biological specimens, molecules, and proteins. Thus, minimizing damage to the specimen is essential for optimum microscopic analysis. In this article we demonstrate, on the example of MoS2, that encapsulation of such crystals between two layers of graphene allows for a dramatic improvement in stability of the studied 2D crystal and permits careful control over the defect nature and formation in it. We present STEM data collected from single-layer MoS2 samples prepared for observation in the microscope through three distinct procedures. The fabricated single-layer MoS2 samples were either left bare (pristine), placed atop a single-layer of graphene, or finally encapsulated between single graphene layers. Their behavior under the electron beam is carefully compared, and we show that the MoS2 sample "sandwiched" between the graphene layers has the highest durability and lowest defect formation rate compared to the other two samples, for very similar experimental conditions.
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Affiliation(s)
- Recep Zan
- School of Physics and Astronomy, University of Manchester , Manchester, M13 9PL, U.K
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Bangert U, Pierce W, Kepaptsoglou DM, Ramasse Q, Zan R, Gass MH, Van den Berg JA, Boothroyd CB, Amani J, Hofsäss H. Ion implantation of graphene-toward IC compatible technologies. Nano Lett 2013; 13:4902-7. [PMID: 24059439 DOI: 10.1021/nl402812y] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Doping of graphene via low energy ion implantation could open possibilities for fabrication of nanometer-scale patterned graphene-based devices as well as for graphene functionalization compatible with large-scale integrated semiconductor technology. Using advanced electron microscopy/spectroscopy methods, we show for the first time directly that graphene can be doped with B and N via ion implantation and that the retention is in good agreement with predictions from calculation-based literature values. Atomic resolution high-angle dark field imaging (HAADF) combined with single-atom electron energy loss (EEL) spectroscopy reveals that for sufficiently low implantation energies ions are predominantly substitutionally incorporated into the graphene lattice with a very small fraction residing in defect-related sites.
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Affiliation(s)
- U Bangert
- School of Materials, The University of Manchester , Manchester M13 9PL, United Kingdom
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Ramasse QM, Seabourne CR, Kepaptsoglou DM, Zan R, Bangert U, Scott AJ. Probing the bonding and electronic structure of single atom dopants in graphene with electron energy loss spectroscopy. Nano Lett 2013; 13:4989-95. [PMID: 23259533 DOI: 10.1021/nl304187e] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
A combination of scanning transmission electron microscopy, electron energy loss spectroscopy, and ab initio calculations reveal striking electronic structure differences between two distinct single substitutional Si defect geometries in graphene. Optimised acquisition conditions allow for exceptional signal-to-noise levels in the spectroscopic data. The near-edge fine structure can be compared with great accuracy to simulations and reveal either an sp(3)-like configuration for a trivalent Si or a more complicated hybridized structure for a tetravalent Si impurity.
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Affiliation(s)
- Quentin M Ramasse
- SuperSTEM Laboratory, STFC Daresbury Campus , Daresbury WA4 4AD, United Kingdom
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21
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Abstract
Nanoholes, etched under an electron beam at room temperature in single-layer graphene sheets as a result of their interaction with metal impurities, are shown to heal spontaneously by filling up with either nonhexagon, graphene-like, or perfect hexagon 2D structures. Scanning transmission electron microscopy was employed to capture the healing process and study atom-by-atom the regrown structure. A combination of these nanoscale etching and reknitting processes could lead to new graphene tailoring approaches.
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Affiliation(s)
- Recep Zan
- School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, United Kingdom
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Ramasse QM, Zan R, Bangert U, Boukhvalov DW, Son YW, Novoselov KS. Direct experimental evidence of metal-mediated etching of suspended graphene. ACS Nano 2012; 6:4063-4071. [PMID: 22533553 DOI: 10.1021/nn300452y] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Atomic resolution high angle annular dark field imaging of suspended, single-layer graphene, onto which the metals Cr, Ti, Pd, Ni, Al, and Au atoms had been deposited, was carried out in an aberration-corrected scanning transmission electron microscope. In combination with electron energy loss spectroscopy, employed to identify individual impurity atoms, it was shown that nanoscale holes were etched into graphene, initiated at sites where single atoms of all the metal species except for gold come into close contact with the graphene. The e-beam scanning process is instrumental in promoting metal atoms from clusters formed during the original metal deposition process onto the clean graphene surface, where they initiate the hole-forming process. Our observations are discussed in the light of calculations in the literature, predicting a much lowered vacancy formation in graphene when metal ad-atoms are present. The requirement and importance of oxygen atoms in this process, although not predicted by such previous calculations, is also discussed, following our observations of hole formation in pristine graphene in the presence of Si-impurity atoms, supported by new calculations which predict a dramatic decrease of the vacancy formation energy, when SiO(x) molecules are present.
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Affiliation(s)
- Quentin M Ramasse
- SuperSTEM Laboratory, STFC Daresbury Campus , Daresbury WA4 4AD, United Kingdom.
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Zan R, Muryn C, Bangert U, Mattocks P, Wincott P, Vaughan D, Li X, Colombo L, Ruoff RS, Hamilton B, Novoselov KS. Scanning tunnelling microscopy of suspended graphene. Nanoscale 2012; 4:3065-3068. [PMID: 22495597 DOI: 10.1039/c2nr30162h] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Suspended graphene has been studied by STM for the first time. Atomic resolution on mono- and bi-layer graphene samples has been obtained after ridding the graphene surface of contamination via high-temperature annealing. Static local corrugations (ripples) have been observed on both types of structures.
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Affiliation(s)
- Recep Zan
- School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK.
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Zan R, Bangert U, Ramasse Q, Novoselov KS. Interaction of Metals with Suspended Graphene Observed by Transmission Electron Microscopy. J Phys Chem Lett 2012; 3:953-958. [PMID: 26286426 DOI: 10.1021/jz201653g] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this Perspective, we present an overview of how different metals interface with suspended graphene, providing a closer look into the metal-graphene interaction by employing high-resolution transmission electron microscopy, especially using high-angle dark field imaging. All studied metals favor sites on the omnipresent hydrocarbon surface contamination rather than on the clean graphene surface and present nonuniform distributions, which never result in continuous films but instead in clusters or nanocrystals, indicating a weak interaction between the metal and graphene. This behavior can be altered to some degree by surface pretreatment (hydrogenation) and high-temperature vacuum annealing. Graphene etching is observed in a scanning transmission electron microscope (STEM) under high vacuum and 60 kV electron beam acceleration voltage conditions for all metals, except for Au. This unusual metal-mediated etching sheds new light on the metal-graphene interaction; it might explain the observed higher frequency of cluster nucleation for certain transition metals and might have implications regarding controlled nanomanipulation, that is, for self-assembly and sculpturing of future graphene-based devices.
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Affiliation(s)
| | | | - Quentin Ramasse
- §SuperSTEM Laboratory, STFC Daresbury, Daresbury WA4 4AD, United Kingdom
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Affiliation(s)
- Recep Zan
- School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, UK
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Zan R, Bangert U, Ramasse Q, Novoselov KS. Metal-graphene interaction studied via atomic resolution scanning transmission electron microscopy. Nano Lett 2011; 11:1087-1092. [PMID: 21271746 DOI: 10.1021/nl103980h] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [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
Distributions and atomic sites of transition metals and gold on suspended graphene were investigated via high-resolution scanning transmission electron microscopy, especially using atomic resolution high angle dark field imaging. All metals, albeit as singular atoms or atom aggregates, reside in the omni-present hydrocarbon surface contamination; they do not form continuous films, but clusters or nanocrystals. No interaction was found between Au atoms and clean single-layer graphene surfaces, i.e., no Au atoms are retained on such surfaces. Au and also Fe atoms do, however, bond to clean few-layer graphene surfaces, where they assume T and B sites, respectively. Cr atoms were found to interact more strongly with clean monolayer graphene, they are possibly incorporated at graphene lattice imperfections and have been observed to catalyze dissociation of C-C bonds. This behavior might explain the observed high frequency of Cr-cluster nucleation, and the usefulness as wetting layer, for depositing electrical contacts on graphene.
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Affiliation(s)
- Recep Zan
- School of Physics, The University of Manchester , Manchester, M13 9PL, United Kingdom
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Atik E, Moromizato JH, Zan R, Ajzenberg M, Esher R, Diniz EM, Souza AT, Martins CO, Bastos JC. [Efficacy of indomethacin in the closure of patent ductus arteriosus in premature newborn infants with cardiac insufficiency. Analysis of 14 cases]. Arq Bras Cardiol 1984; 43:185-9. [PMID: 6535546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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