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Swamy NK, Mohana KNS, Hegde MB, Madhusudana AM. Fabrication of 1D graphene nanoribbon and malenized linseed oil-based nanocomposite: a highly impervious bio-based anti-corrosion coating material for mild steel. J APPL ELECTROCHEM 2022. [DOI: 10.1007/s10800-022-01692-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Uzundal CB, Sahin O, Gokturk PA, Wu H, Mugele F, Ulgut B, Suzer S. X-ray Photoelectron Spectroscopy with Electrical Modulation Can Be Used to Probe Electrical Properties of Liquids and Their Interfaces at Different Stages. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:16989-16999. [PMID: 31794669 DOI: 10.1021/acs.langmuir.9b03134] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Operando X-ray photoelectron spectroscopy (o-XPS) has been used to record the binding energy shifts in the C 1s peak of a pristine poly(ethylene glycol) (PEG) liquid drop in an electrowetting on dielectric (EWOD) geometry and after exposing it to several high-voltage breakdown processes. This was achieved by recording XPS data while the samples were subjected to 10 V dc and ac (square-wave modulation) actuations to extract electrical information related to the liquid and its interface with the dielectric. Through analysis of the XPS data under ac actuation, a critical frequency of 170 Hz is extracted for the pristine PEG, which is translated to a resistance value of 14 MΩ for the liquid and a capacitance value of 60 pF for the dielectric, by the help of simulations using an equivalent circuit model and also by XPS analyses of a mimicking device under similar conditions. The same measurements yield an increased value of 23 MΩ for the resistance of the liquid after the breakdown by assuming that the capacitance of the dielectric stays constant. In addition, an asymmetry in polarity dependence is observed with respect to both the onset of the breakdown voltage and also the leakage behavior of the deteriorated (PEG + dielectric) system such that deviations are more pronounced at positive voltages. Both dc and ac behaviors of the postbreakdown system can also be simulated, but only by introducing an additional element, a diode or a polarity- and magnitude-dependent voltage source (VCVS), which might be attributed to negative charge accumulation at the interface. Measurements for a liquid mixture of PEG with 8% ionic liquid yields an almost 2 orders of magnitude smaller resistance for the drop as a result of the enhanced conductivity by the ions. Coupled with modeling, XPS measurements under dc and ac modulations enable probing unique electrochemical properties of liquid/solid interfaces.
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Affiliation(s)
- Can Berk Uzundal
- Department of Chemistry , Bilkent University , 06800 Ankara , Turkey
| | - Ozgur Sahin
- Department of Chemistry , Bilkent University , 06800 Ankara , Turkey
| | | | - Hao Wu
- Physics of Complex Fluids , University of Twente , 7522 NB , Enschede , The Netherlands
| | - Frieder Mugele
- Physics of Complex Fluids , University of Twente , 7522 NB , Enschede , The Netherlands
| | - Burak Ulgut
- Department of Chemistry , Bilkent University , 06800 Ankara , Turkey
| | - Sefik Suzer
- Department of Chemistry , Bilkent University , 06800 Ankara , Turkey
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Ren X, Kim CY, Canavero S. Bridging the gap: Spinal cord fusion as a treatment of chronic spinal cord injury. Surg Neurol Int 2019; 10:51. [PMID: 31528389 PMCID: PMC6743693 DOI: 10.25259/sni-19-2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 02/06/2019] [Indexed: 12/15/2022] Open
Abstract
Despite decades of animal experimentation, human translation with cell grafts, conduits, and other strategies has failed to cure patients with chronic spinal cord injury (SCI). Recent data show that motor deficits due to spinal cord transection in animal models can be reversed by local application of fusogens, such as Polyethylene glycol (PEG). Results proved superior at short term over all other treatments deployed in animal studies, opening the way to human trials. In particular, removal of the injured spinal cord segment followed by PEG fusion of the two ends along with vertebral osteotomy to shorten the spine holds the promise for a cure in many cases.
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Affiliation(s)
- Xiaoping Ren
- Hand and Microsurgery Center, Second Affiliated Hospital of Harbin Medical University, Nangang, Harbin, China
- State-Province Key Laboratories of Biomedicine-Pharmaceutics, Harbin Medical University, Nangang, Harbin, China
- Heilongjiang Medical Science Institute, Harbin Medical University, Nangang, Harbin, China
| | - C-Yoon Kim
- Department of Stem Cell Biology, School of Medicine, Konkuk University, Seoul, Korea
| | - Sergio Canavero
- HEAVEN-GEMINI International Collaborative Group, Turin, Italy
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Ausman JI. Is it time to perform the first human head transplant? Comment on the CSA (CephaloSomatic Ansatomisis) paper by Ren, Canavero, and colleagues. Surg Neurol Int 2018; 9:28. [PMID: 29492328 PMCID: PMC5820846 DOI: 10.4103/sni.sni_472_17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 12/12/2017] [Indexed: 01/13/2023] Open
Affiliation(s)
- James I Ausman
- Emeritus Editor-in-Chief and Publisher, SNI Publications, Professor, Neurosurgery, David Geffen School of Medicine at UCLA, Los Angeles, CA and Harbor-UCLA Medical Center, Torrance, CA, USA
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Kim CY, Sikkema WKA, Kim J, Kim JA, Walter J, Dieter R, Chung HM, Mana A, Tour JM, Canavero S. Effect of Graphene Nanoribbons (TexasPEG) on locomotor function recovery in a rat model of lumbar spinal cord transection. Neural Regen Res 2018; 13:1440-1446. [PMID: 30106057 PMCID: PMC6108198 DOI: 10.4103/1673-5374.235301] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
A sharply transected spinal cord has been shown to be fused under the accelerating influence of membrane fusogens such as polyethylene glycol (PEG) (GEMINI protocol). Previous work provided evidence that this is in fact possible. Other fusogens might improve current results. In this study, we aimed to assess the effects of PEGylated graphene nanoribons (PEG-GNR, and called “TexasPEG” when prepared as 1wt% dispersion in PEG600) versus placebo (saline) on locomotor function recovery and cellular level in a rat model of spinal cord transection at lumbar segment 1 (L1) level. In vivo and in vitro experiments (n = 10 per experiment) were designed. In the in vivo experiment, all rats were submitted to full spinal cord transection at L1 level. Five weeks later, behavioral assessment was performed using the Basso Beattie Bresnahan (BBB) locomotor rating scale. Immunohistochemical staining with neuron marker neurofilament 200 (NF200) antibody and astrocytic scar marker glial fibrillary acidic protein (GFAP) was also performed in the injured spinal cord. In the in vitro experiment, the effects of TexasPEG application for 72 hours on the neurite outgrowth of SH-SY5Y cells were observed under the inverted microscope. Results of both in vivo and in vitro experiments suggest that TexasPEG reduces the formation of glial scars, promotes the regeneration of neurites, and thereby contributes to the recovery of locomotor function of a rat model of spinal cord transfection.
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Affiliation(s)
- C-Yoon Kim
- Department of Stem Cell Biology, School of Medicine, Konkuk University; Department of Laboratory Animal Medicine, College of Veterinary Medicine, Seoul National University, Seoul, Korea
| | - William K A Sikkema
- Department of Chemistry, Department of Materials Science and NanoEngineering, and The NanoCarbon Center, Rice University, Houston, TX, USA
| | - Jin Kim
- Department of Laboratory Animal Medicine, College of Veterinary Medicine, Seoul National University, Seoul, Korea
| | - Jeong Ah Kim
- Biomedical Omics Group, Korea Basic Science Institute, Cheongju-si, Chungbuk, Korea
| | - James Walter
- Research Service, Hines Veterans Administration Hospital, Hines, IL, USA
| | - Raymond Dieter
- Research Service, Hines Veterans Administration Hospital, Hines, IL, USA
| | - Hyung-Min Chung
- Department of Stem Cell Biology, School of Medicine, Konkuk University, Seoul, Korea
| | - Andrea Mana
- HEAVEN/GEMINI International Collaborative Group, Turin, Italy
| | - James M Tour
- Department of Chemistry, Department of Materials Science and NanoEngineering, and The NanoCarbon Center, Rice University, Houston, TX, USA
| | - Sergio Canavero
- HEAVEN/GEMINI International Collaborative Group, Turin, Italy
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