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Fast Ion-Chelate Dissociation Rate for MRI of Labile Zinc with Frequency-Specific Encodability.

J Am Chem Soc 2021 Jul 23. Epub 2021 Jul 23.

Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel.

Fast ion-chelate dissociation rates and weak ion-chelate affinities are desired kinetic and thermodynamic features for imaging probes to allow reversible binding and to prevent deviation from basal ionic levels. Nevertheless, such properties often result in poor readouts upon ion binding, frequently result in low ion specificity, and do not allow the detection of a wide range of concentrations. Herein, we show the design, synthesis, characterization, and implementation of a Zn-probe developed for MRI that possesses reversible Zn-binding properties with a rapid dissociation rate ( = 845 ± 35 s) for the detection of a wide range of biologically relevant concentrations. Read More

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Detection of Cholera Toxin with Surface Plasmon-Field Enhanced Fluorescent Spectroscopy (SPFS).

Biotechnol Appl Biochem 2021 Jul 23. Epub 2021 Jul 23.

Department of Material Science and Engineering, Gebze Technical University, Kocaeli, Turkey.

In this work, a biosensor based on Surface Plasmon-Field Enhanced Florescence Spectroscopy (SPFS) method was successfully constructed to detect the truncated form of cholera toxin, i.e., its beta subunit (CTX-B). Read More

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Quantification of tumor microenvironment acidity in glioblastoma using principal component analysis of dynamic susceptibility contrast enhanced MR imaging.

Sci Rep 2021 Jul 22;11(1):15011. Epub 2021 Jul 22.

Department of Radiology, Perelman School of Medicine, Hospital of University of Pennsylvania, University of Pennsylvania, Philadelphia, PA, USA.

Glioblastoma (GBM) has high metabolic demands, which can lead to acidification of the tumor microenvironment. We hypothesize that a machine learning model built on temporal principal component analysis (PCA) of dynamic susceptibility contrast-enhanced (DSC) perfusion MRI can be used to estimate tumor acidity in GBM, as estimated by pH-sensitive amine chemical exchange saturation transfer echo-planar imaging (CEST-EPI). We analyzed 78 MRI scans in 32 treatment naïve and post-treatment GBM patients. Read More

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Measuring radiofrequency fields in NMR spectroscopy using offset-dependent nutation profiles.

J Magn Reson 2021 Jul 6;330:107032. Epub 2021 Jul 6.

Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India. Electronic address:

The application of NMR spectroscopy for studying molecular and reaction dynamics relies crucially on the measurement of the magnitude of radiofrequency (RF) fields that are used to nutate or lock the nuclear magnetization. Here, we report a method for measuring RF field amplitudes that leverages the intrinsic modulations observed in offset-dependent NMR nutation profiles of small molecules. Such nutation profiles are exquisitely sensitive to the magnitude of the RF field, and B values ranging from 1 to 2000 Hz, as well the inhomogeneity in B distributions, can be determined with high accuracy and precision using this approach. Read More

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Hyperpolarized MRI, functional MRI, MR spectroscopy and CEST to provide metabolic information in vivo.

Curr Opin Chem Biol 2021 Jul 20;63:209-218. Epub 2021 Jul 20.

Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Medical Radiation Physics, Lund University, Lund, Sweden.

Access to metabolic information in vivo using magnetic resonance (MR) technologies has generally been the niche of MR spectroscopy (MRS) and spectroscopic imaging (MRSI). Metabolic fluxes can be studied using the infusion of substrates labeled with magnetic isotopes, with the use of hyperpolarization especially powerful. Unfortunately, these promising methods are not yet accepted clinically, where fast, simple, and reliable measurement and diagnosis are key. Read More

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Lanthanide complexes of DOTA-nitroxide conjugates for redox imaging: spectroelectrochemistry, CEST, relaxivity, and cytotoxicity.

Dalton Trans 2021 Jul 22. Epub 2021 Jul 22.

Univ. Grenoble Alpes, CNRS, DCM, 38000 Grenoble, France.

The lanthanide(iii) complexes (Gd, Eu, Dy, and Yb) of DOTA tris(amide) and bis(amide) derivatives (L1 and L2) featuring one redox active TEMPO arm were prepared. Ligand L2 harbours an alkyne fragment for further functionalization. The X-ray crystal structure of ligand L2 in complexation with Na+ was solved. Read More

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Chemical Exchange Saturation Transfer MRI in Central Nervous System Tumours on a 1.5T MR-Linac.

Radiother Oncol 2021 Jul 16. Epub 2021 Jul 16.

Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada; Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.

Purpose: To describe the implementation and initial results of using Chemical Exchange Saturation Transfer (CEST) for monitoring patients with central nervous system (CNS) tumours treated using a 1.5 tesla MR-guided radiotherapy system.

Methods: CNS patients were treated with up to 30 fractions (total dose up to 60 Gy) using a 1. Read More

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Multi-parametric Z-spectral MRI may have a good performance for glioma stratification in clinical patients.

Eur Radiol 2021 Jul 17. Epub 2021 Jul 17.

Department of Radiology College of Medicine, University of Illinois at Chicago, Chicago, IL, USA.

Objectives: To comprehensively and noninvasively risk-stratify glioma grade, isocitrate dehydrogenase (IDH) genotype, and 1p/19q codeletion status using multi-contrast Z-spectral magnetic resonance imaging (MRI).

Methods: One hundred and thirteen patients with glioma were retrospectively included. Multiple contrasts contributing to Z-spectra, including direct saturation of water (DSW), semi-solid magnetization transfer contrast (MTC), amide proton transfer (APT) effect, aliphatic nuclear Overhauser effect, and the 2-ppm chemical exchange saturation transfer peak ([email protected]), were fitted with five individual Lorentzian functions. Read More

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Therapeutic Use of Microbubbles and Ultrasound in Acute Peripheral Arterial Thrombosis: A Systematic Review.

Ultrasound Med Biol 2021 Jul 13. Epub 2021 Jul 13.

Department of Surgery, Amsterdam University Medical Centers (VUmc), Amsterdam, The Netherlands; Department of Physiology, Amsterdam University Medical Centers (VUmc), Amsterdam, The Netherlands.

Catheter-directed thrombolysis (CDT) for acute peripheral arterial occlusion is time consuming and carries a risk of major hemorrhage. Contrast-enhanced sonothrombolysis (CEST) might enhance outcomes compared with standard CDT. In the study described here, we systematically reviewed all in vivo studies on contrast-enhanced sonothrombolysis in a setting of arterial thrombosis. Read More

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Volumetric glutamate imaging (GluCEST) using 7T MRI can lateralize nonlesional temporal lobe epilepsy: A preliminary study.

Brain Behav 2021 Jul 13:e02134. Epub 2021 Jul 13.

Penn Epilepsy Center, Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA, USA.

Introduction: Drug-resistant epilepsy patients show worse outcomes after resection when standard neuroimaging is nonlesional, which occurs in one-third of patients. In prior work, we employed 2-D glutamate imaging, Glutamate Chemical Exchange Saturation Transfer (GluCEST), to lateralize seizure onset in nonlesional temporal lobe epilepsy (TLE) based on increased ipsilateral GluCEST signal in the total hippocampus and hippocampal head. We present a significant advancement to single-slice GluCEST imaging, allowing for three-dimensional analysis of brain glutamate networks. Read More

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Magnetization Transfer to Enhance NOE Cross-Peaks among Labile Protons: Applications to Imino-Imino Sequential Walks in SARS-CoV-2-Derived RNAs.

Angew Chem Weinheim Bergstr Ger 2021 May 1;133(21):11991-11998. Epub 2021 May 1.

Department of Chemical and Biological Physics Weizmann Institute of Science 7610001 Rehovot Israel.

2D NOESY plays a central role in structural NMR spectroscopy. We have recently discussed methods that rely on solvent-driven exchanges to enhance NOE correlations between exchangeable and non-exchangeable protons in nucleic acids. Such methods, however, fail when trying to establish connectivities within pools of labile protons. Read More

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CryptoCEST: A promising tool for spatially resolved identification of fungal brain lesions and their differentiation from brain tumors with MRI.

Neuroimage Clin 2021 Jun 24;31:102737. Epub 2021 Jun 24.

Biomedical MRI, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium. Electronic address:

Infectious brain lesions caused by the pathogenic fungi Cryptococcus neoformans and C. gattii, also referred to as cryptococcomas, could be diagnosed incorrectly as cystic brain tumors if only based on conventional magnetic resonance (MR) images. Previous MR spectroscopy (MRS) studies showed high local concentrations of the fungal disaccharide trehalose in cryptococcomas. Read More

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Identification of extracellular nanoparticle subsets by nuclear magnetic resonance.

Chem Sci 2021 Apr 29;12(24):8311-8319. Epub 2021 Apr 29.

NMR Research Unit, University of Oulu Finland

Exosomes are a subset of secreted lipid envelope-encapsulated extracellular vesicles (EVs) of 50-150 nm diameter that can transfer cargo from donor to acceptor cells. In the current purification protocols of exosomes, many smaller and larger nanoparticles such as lipoproteins, exomers and microvesicles are typically co-isolated as well. Particle size distribution is one important characteristics of EV samples, as it reflects the cellular origin of EVs and the purity of the isolation. Read More

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Photosensitive MRI biosensor for BCRP-Targeted uptake and light-induced inhibition of tumor cells.

Talanta 2021 Oct 17;233:122501. Epub 2021 May 17.

Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan, 430071, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China; Wuhan National Laboratory for Optoelectronics, Wuhan, 430074, PR China. Electronic address:

Riboflavin and its derivatives are the most important coenzymes in vivo metabolism, and are closely related to life activities. In this paper, the first photolysis Xe biosensor was developed by combining cryptophane-A with riboflavin moiety, which showed photosensitivity recorded by hyperpolarized Xe NMR/MRI technology with an obvious chemical shift change of 5.3 ppm in aqueous solution. Read More

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October 2021

Monitoring of Rolling Circle Amplification on a Solid Support by Surface Plasmon Resonance and Optical Waveguide Spectroscopy.

ACS Appl Mater Interfaces 2021 Jul 2;13(27):32352-32362. Epub 2021 Jul 2.

Biosensor Technologies, AIT-Austrian Institute of Technology GmbH, Konrad-Lorenz-Straße 24, 3430 Tulln an der Donau, Austria.

The growth of surface-attached single-stranded deoxyribonucleic acid (ssDNA) chains is monitored using an evanescent wave optical biosensor that combines surface plasmon resonance (SPR) and optical waveguide spectroscopy (OWS). The "grafting-from" growth of ssDNA chains is facilitated by rolling circle amplification (RCA), and the gradual prolongation of ssDNA chains anchored to a gold sensor surface is optically tracked in time. At a sufficient density of the polymer chains, the ssDNA takes on a brush architecture with a thickness exceeding 10 μm, supporting a spectrum of guided optical waves traveling along the metallic sensor surface. Read More

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MoS Decoration Followed by P Inclusion over Ni-Co Bimetallic Metal-Organic Framework-Derived Heterostructures for Water Splitting.

Inorg Chem 2021 Jul 1;60(14):10772-10780. Epub 2021 Jul 1.

Department of BioNano Technology, Gachon University, GyeongGi -Do 13120, Republic of Korea.

Demonstrating a highly efficient non-noble bifunctional catalyst for complete water electrolysis remains challenging because of kinetic limitations and crucial importance for future energy harvesting. Herein, a low-cost, integrated composite of a Ni-Co metal-organic framework decorated with thin MoS nanosheets was synthesized by a simple hydrothermal method followed by carbonization and phosphorization for electrochemical oxygen and hydrogen evolution reactions. Such a composite heterostructure exhibits outstanding performance in the electrocatalysis process with a lower overpotential of 184 mV for the oxygen evolution reaction (OER) and 84 mV for the hydrogen evolution reaction (HER) in 1. Read More

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Low duty cycle pulse trains for exchange rate insensitive chemical exchange saturation transfer MRI.

Magn Reson Med 2021 Jul 1. Epub 2021 Jul 1.

Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.

Purpose: To introduce and validate a pulse scheme that uses low duty cycle trains of π-pulses to achieve saturation that is relatively insensitive to exchange rate yet linearly dependent on labile proton concentration.

Methods: Simulations were performed to explore the exchange rate sensitivity of π-pulse trains and continuous wave chemical exchange saturation transfer (CEST) signals. Creatine phantoms with varying pH and varying concentrations were imaged to demonstrate pH insensitivity and concentration dependence of low duty cycle π-pulse saturation. Read More

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Comparison of Amino Acid PET to Advanced and Emerging MRI Techniques for Neurooncology Imaging: A Systematic Review of the Recent Studies.

Mol Imaging 2021 20;2021:8874078. Epub 2021 Jan 20.

Virginia Tech Carilion School of Medicine, Roanoke, VA, USA.

Introduction: Standard neuroimaging protocols for brain tumors have well-known limitations. The clinical use of additional modalities including amino acid PET (aaPET) and advanced MRI (aMRI) techniques (including DWI, PWI, and MRS) is emerging in response to the need for more accurate detection of brain tumors. In this systematic review of the past 2 years of the literature, we discuss the most recent studies that directly compare or combine aaPET and aMRI for brain tumor imaging. Read More

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January 2021

Optimization of the Electrode Properties for High-Performance Ni-Rich Li-Ion Batteries.

ACS Appl Mater Interfaces 2021 Jul 27;13(26):30643-30652. Epub 2021 Jun 27.

Center of Excellence for Energy Storage Technology (CEST), Department of Chemical and Biomolecular Engineering, School of Energy Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Rayong 21210, Thailand.

The microstructure of the electrodes in lithium-ion batteries (LIBs) strongly affects their gravimetric and volumetric energy and power as well as their cycle life. Especially, the effect of the microstructure in the case of next-generation Ni-rich cathode materials has not yet been investigated. A comprehensive understanding of the calendering process is therefore necessary to find an optimal level of the electrode microstructure that can enhance lithium-ion transportation, minimize plastic deformation, and improve conductivity. Read More

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Accelerated multi-target chemical exchange saturation transfer magnetic resonance imaging of the mouse heart.

Phys Med Biol 2021 Jul 16;66(14). Epub 2021 Jul 16.

Department of Bioengineering, UC Berkeley, Berkeley CA, United States of America.

Cardiac chemical exchange saturation transfer-magnetic resonance imaging (CEST-MRI) has been used to probe levels of various metabolites that provide insight into myocardial structure and function. However, imaging of the heart using CEST-MRI is prolonged by the need to repeatedly acquire multiple images for a full Z-spectrum and to perform saturation and acquisition around cardiac and respiratory cycles. Compressed sensing (CS) reconstruction of sparse data enables accelerated acquisition, but reconstruction artifacts may bias subsequently derived measures of CEST contrast. Read More

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Dimerization of Cadherin-11 involves multi-site coupled unfolding and strand swapping.

Structure 2021 Jun 22. Epub 2021 Jun 22.

Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, 701 West 168th Street, New York, NY 10032, USA. Electronic address:

Cadherin extracellular domain 1 (EC1) mediates homophilic dimerization in adherens junctions. Conserved Trp2 and Trp4 residues in type II cadherins anchor the EC1 A strand intermolecularly in strand-swapped dimers. Herein, NMR spectroscopy is used to elucidate the roles of Trp2 and Trp4 in Cadherin-11 dimerization. Read More

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Scalable 18,650 aqueous-based supercapacitors using hydrophobicity concept of anti-corrosion graphite passivation layer.

Sci Rep 2021 Jun 22;11(1):13082. Epub 2021 Jun 22.

Centre of Excellence for Energy Storage Technology (CEST), Department of Chemical and Biomolecular Engineering, School of Energy Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Rayong, 21210, Thailand.

Scalable aqueous-based supercapacitors are ideal as future energy storage technologies due to their great safety, low cost, and environmental friendliness. However, the corrosion of metal current collectors e.g. Read More

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Quasi-steady-state chemical exchange saturation transfer (QUASS CEST) MRI analysis enables T normalized CEST quantification - Insight into T contribution to CEST measurement.

Authors:
Phillip Zhe Sun

J Magn Reson 2021 Aug 8;329:107022. Epub 2021 Jun 8.

Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, United States; Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta GA, United States. Electronic address:

Chemical exchange saturation transfer (CEST) MRI depends not only on the labile proton concentration and exchange rate but also on relaxation rates, particularly T relaxation time. However, T normalization has shown to be not straightforward under non-steady-state conditions and in the presence of radiofrequency spillover effect. Our study aimed to test if the combined use of the new quasi-steady-state (QUASS) analysis and inverse CEST calculation facilitates T normalization for improved CEST quantification. Read More

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Acid-catalyzed proton exchange as a novel approach for relaxivity enhancement in Gd-HPDO3A-like complexes.

Chem Sci 2020 Jul 6;11(30):7829-7835. Epub 2020 Jul 6.

Department of Science and Technological Innovation, Università del Piemonte Orientale Viale T. Michel 11 15121 Alessandria Italy

A current challenge in medical diagnostics is how to obtain high MRI relaxation enhancement using Gd-based contrast agents (CAs) containing the minimum concentration of Gd ions. We report that in GdHPDO3A-like complexes a primary amide group located in close proximity to the coordinated hydroxyl group can provide a strong relaxivity enhancement at slightly acidic pH. A maximum relaxivity of = 9. Read More

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Effect of fluoroethylene carbonate on the transport property of electrolytes towards Ni-rich Li-ion batteries with high safety.

Chem Commun (Camb) 2021 Jul 10;57(55):6732-6735. Epub 2021 Jun 10.

Centre of Excellence for Energy Storage Technology (CEST), Department of Chemical and Biomolecular Engineering, School of Energy Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Rayong 21210, Thailand.

Transport phenomena and the solvation structure of lithium ions (Li) and hexafluorophosphate anions (PF) in electrolytes with different fluoroethylene carbonate (FEC) concentrations as well as the electrochemical performance and safety of Ni-rich Li-ion battery cells at the 18650 cylindrical cell level are investigated. We have found that the electrolyte with an optimized FEC concentration (25% v/v) can effectively enhance the transport property in terms of the Li transference number and contact ion pair (CIP) ratio leading to high performance and safety of practical 18650 cylindrical LIBs. Read More

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Visualization of Spatial Distribution of Spermatogenesis in Mouse Testes Using Creatine Chemical Exchange Saturation Transfer Imaging.

J Magn Reson Imaging 2021 May 30. Epub 2021 May 30.

Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.

Background: When determining treatment strategies for male infertility, it is important to evaluate spermatogenesis and its spatial distribution in the testes.

Purpose: To investigate the usefulness of creatine chemical exchange saturation transfer (CrCEST) imaging for evaluating spermatogenesis and its spatial distribution.

Study Type: Prospective. Read More

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Chemical exchange saturation transfer for detection of antiretroviral drugs in brain tissue.

AIDS 2021 May 27. Epub 2021 May 27.

Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198 USA Department of Radiology, University of Nebraska Medical Center, Omaha, NE 68198 USA.

Objective: Antiretroviral drug (ARV) theranostics facilitates the monitoring of biodistribution and efficacy of therapies designed to target human immunodeficiency virus type-1 (HIV-1) reservoirs. To this end, we have now deployed intrinsic drug chemical exchange saturation transfer (CEST) contrasts to detect ARVs within the central nervous system (CNS).

Design And Methods: CEST effects for lamivudine (3TC) and emtricitabine (FTC) were measured by asymmetric magnetization transfer ratio analyses. Read More

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Chemical exchange saturation transfer imaging for epilepsy secondary to tuberous sclerosis complex at 3 T: Optimization and analysis.

NMR Biomed 2021 May 27:e4563. Epub 2021 May 27.

Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China.

The homeostasis of various metabolites is impaired in epilepsy secondary to the tuberous sclerosis complex (TSC). Chemical exchange saturation transfer (CEST) imaging is an emerging molecular MRI technique that can detect various metabolites and proteins in vivo. However, the role of CEST imaging for TSC-associated epilepsy has not been assessed. Read More

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Imaging of Allografted Glial-Restricted Progenitor Cell Survival and Hydrogel Scaffold Biodegradation.

ACS Appl Mater Interfaces 2021 May 12;13(20):23423-23437. Epub 2021 May 12.

The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins School of Medicine, Baltimore, Maryland 21205, United States.

Transplanted glial-restricted progenitor (GRP) cells have potential to focally replace defunct astrocytes and produce remyelinating oligodendrocytes to avert neuronal death and dysfunction. However, most central nervous system cell therapeutic paradigms are hampered by high initial cell death and a host anti-graft immune response. We show here that composite hyaluronic acid-based hydrogels of tunable mechanical strengths can significantly improve transplanted GRP survival and differentiation. Read More

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The electrochemistry of size dependent graphene liquid phase exfoliation: capacitance and ionic transport.

Phys Chem Chem Phys 2021 May;23(20):11616-11623

Department of Applied physics, Faculty of Sciences and Liberal Arts, Rajamangala University of Technology Isan, Nakhon Ratchasima 30000, Thailand.

Recently, graphene-based materials have become ubiquitous in electrochemical devices including electrochemical sensors, electrocatalysts, capacitive and membrane desalination and energy storage devices. However, many of the electrochemical properties of graphene (particularly the capacitance and ionic transport) are not yet fully understood. This paper explores the capacitance and ionic transport properties of size dependent graphene (from 100 nm to 1 μm) prepared through the liquid phase exfoliation of graphite in which the size of graphene was finely selected using a multi-step centrifugation technique. Read More

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