bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Glucose Sensor Prepared By the Immobilization of Glucose Oxidase Together with Nanocarbons and Prussian Blue Using Electrodeposition Method
Authors: Yasuzawa Mikito , Jhong Huan-Ping , Kurashina Masashi , Wang Chen-Hao , Chiang Wei-Hung 
Published: February 2020

A variety of approaches have been explored in the immobilization of enzyme onto the electrodes. Electrochemical deposition and electropolymerization procedure are interesting, since it allows localization of enzymes onto extremely small electrode surfaces, and permits the formation of multilayer structures. The purpose of these strategies are to immobilize enzyme in a highly active state and, at the same time, provide a membrane preferentially permeable to hydrogen peroxide over endogenous electroactive species, such as uric and ascorbic acids. Improvement of sensor sensitivities are of great attention, since it allow minimizing the size of the sensor and are desirable for the fabrication of implantable biosensor for continuous glucose monitoring. Nanocarbon, such as carbon nanotube and graphene are known to have high electroconductivity. Moreover, Prussian blue (PB) is an efficient redox mediator with the highest catalytic activity toward hydrogen peroxide reduction. In this study, we attempt to prepare an electrode, which both nanocarbon and Prussian blue are immobilized together with enzyme, glucose oxidase, to obtain a glucose sensor with high sensitivity.
In order to immobilize the enzyme together with nanocarbon and Prussian blue, firstly, dispersed aqueous solution of nanocarbon and Prussian blue were prepared using gelling agent Gallen gum. Secondly, electrodeposition was performed using this solution on the platinum electrode, by applying a constant potential of 1.3 V (vs. Ag/AgCl). Finally, the electropolymerization of 0-phenylenediamine was carried out by applying a constant potential of 0.7 V (vs. Ag/AgCl), which will increase the stability of the electrodeposited film by comprehensive polymer film formation. After the enzyme immobilization, the electrode was soaked in phosphate buffer solution (PBS) with stirring for three days in order to remove weakly absorbed enzyme on the electrode. In contrast, electrodes without PB and/or nanocarbon were also prepared in the same procedure for comparison.
A Quartz Crystal Microbalance (QCM) was employed to investigate the behavior of film formation on the electrode during the electrodeposition. It was evident to see that the electrodeposition of the solution with PB showed ten times higher deposit amount than that without it. The glucose response measurement was performed at an applied potential of 0.6V (vs. Ag/AgCl) in 0.1 M PBS containing 0.1 M sodium chloride at 40 ˚C. All prepared GOx-immobilized electrodes showed good response toward the addition of glucose, while the electrode containing both PB and carbon nanotube provided the highest response current with good long-term stability.
Crystallization of Atomic Layer Deposited MgO Thin Filmsas a Buffer Layer for Rocksalt Beo Film Growth
Authors: Lee Hoin , Wang Bowen , Hwang Cheol Seong 
Published: February 2020

Rocksalt structure beryllium oxide (BeO) thin film has been highlighted as an exceptional high-k dielectric material for various semiconductor device application because it can have a very high-k value of > 200 and high band gap of ~ 10 eV simultaneously. However, this was an only theoretical expectation based on the first-principles calculation. Also, the stable crystal structure of BeO is wurtzite at normal thermal Atomic Layer Deposition (ALD) processing conditions of which k-value is only ~8, whereas the rocksalt structure BeO could be stabilized only under an extremely high-pressure condition (> 100 GPa). Therefore, it is expected that the usual ALD process of BeO film may result in the wurtzite structure film.
Considering the interfacial tensile strain offered by the larger MgO lattice parameter with a cubic-based rocksalt crystal structure, which is 4.21 Å while BeO lattice parameter is 2.70 Å for hexagonal-based wurtzite crystal structure and 3.62 Å for cubic-based rocksalt crystal structure, the adoption of cubic-based MgO as a buffer layer may enable the transition of BeO crystal structure from wurtzite to quasi-rocksalt. This work reported the optimization of both Thermal and Plasma-Enhanced ALD (TALD, and PEALD) process and post-annealing conditions of MgO and their influences on the crystallization properties of BeO on top of the MgO buffer layer, observed by X-Ray Diffraction (Figure 1 (a), (b)), Transmission Electron Microscope Selected Area Diffraction. Moreover, the electronic properties of MgO and BeO thin films, especially leakage current and dielectric constant, were verified through the measurement of Metal-Insulator-Metal (MIM) device (Figure 1 (c)).
This work, thus, attempted to grow MgO film by TALD, and PEALD as a buffer layer for the rocksalt BeO film growth. Although the growth of the BeO film on top of the rocksalt MgO film is ongoing project, this work can provide a fundamental step toward the final goal of rocksalt BeO film growth by an ALD method.

Figure 1
Investigation on Electrical Properties of Hydrogen Doped Sputtered Boron Carbon Nitride Thin Films
Authors: Nehate Shraddha Dhanraj , Sundaram Kalpathy B. 
Published: February 2020

Interlayer dielectric materials (ILD) play a crucial role of isolating electrically conductive and semiconducting features on the devices [1]. Due to constant scaling down of device dimensions, the interconnect delay (τ = R x C) can be reduced by decreasing resistance of conductor and capacitance of ILD. Reduced capacitance can be achieved by high quality insulating film with low dielectric constant. Boron carbon nitride (BCN) films have achieved attention due to their complicated crystalline structure and unique properties. Atomic bonding similarities amongst boron, carbon and nitrogen allow formation of compounds with wide compositional range. BCN compounds are expected to combine the excellent properties of diamond, B4C and BN with their properties adaptable depending on their composition and structure [2, 3].
In this study, electrical properties of hydrogen doped BCN thin films will be investigated. BCN films are sputtered by B4C and BN targets. Films are deposited at different temperatures in presence of hydrogen/argon to investigate the influence of temperature and hydrogen gas on the electrical properties of BCN thin films.
References
[1] S. P. Muraka, M. Eizenberg, and A. K. Sinha, Interlayer dielectrics for semiconductor technologies vol. 1: Elsevier, 2003.
[2] A. Prakash and K. B. Sundaram, "Studies on electrical properties of RF sputtered deposited boron carbon nitride thin films," ECS Journal of Solid State Science and Technology, vol. 4, pp. N25-N29, 2015.
[3] M. K. Mazumder, R. Moriyama, D. Watanabe, C. Kimura, H. Aoki, and T. Sugino, "Ag diffusion in low-k materials (BCN and SiOC) and its challenges for future interconnection," Japanese journal of applied physics, vol. 46, p. 2006, 2007.
Thermodynamically Controlled Microstructure of Binary Alloy for Efficient Electrochemical Conversion of CO2 to C2H4
Authors: Kim Jeong Eun , Yang Ki Dong , Jang Jun Ho , Im Sang Won , Yeo Jia Bin , Nam Ki Tae 
Published: February 2020

Since the first development of synthetic plastics, people have been getting a variety of plastics mainly from petroleum, which drove modern civilization. Typically, polyethylene is the most frequently and widely used plastic. But the depletion of fossil fuels and the simultaneous increase in the concentration of carbon dioxide(CO2), which is at a dangerous level, have led to the need to reduce petroleum use and to reduce CO2. The conversion of CO2 to ethylene, the raw material for polyethylene, is a very promising strategy for achieving that. Electrochemically, ethylene can be obtained by reducing CO2 using sustainable electricity.
Cu is reported to be the only single element catalyst that is capable of producing hydrocarbons with more than one carbon such as ethylene(C2H4) from CO2. It is because Cu has moderate intermediate binding energy. However, pure Cu catalyst represents poor C2H4 production efficiency because of the activity and selectivity problem. Therefore, alloying Cu with other elements can be one of the best strategy to enhance the activity and selectivity of the catalysis. However, conventional strategy to alloy Cu with other elements and modify the d-orbital energy failed to enhance selectivity for C2H4 because of the scaling relationship between binding energy of intermediates.
In this work, controlled microstructure of binary alloy was investigated as a new strategy for selective C2H4 production. Based on the thermodynamic database, the microstructure of Cu-X alloy was carefully designed. By adopting the terminal solid solution system, in which phase segregation take place, unlike conventional homogeneous solid solution system, the microstructure of the alloy consisting of lamellar structure could be controlled. In that system, different binding affinities with intermediates of segregated phases were taken advantage of. The synergetic effect between different phases was investigated by controlling the density of phase boundaries based on the understanding on metallurgy of alloy system. As the result, the selectivity for C2H4 increased with the increase of the density of phase boundary, which suggests the CO spillover between CO-selective phase and Cu and the following CO-CO dimerization. This work provided new catalyst design strategy for efficient electrochemical CO2 conversion to targeted chemicals.
Perspectives on the Development and Evaluation of Electrode Materials for Electrochemical Deionization Processes
Authors: Shanbhag Sneha , Liu Xitong , Whitacre Jay , Mauter Meagan 
Published: February 2020

Electrochemical de-ionization processes offer great promise in complementing existing water desalination technologies in purifying water over a range of salinity values.1, 2 Theoretical evaluations have demonstrated that these methods demonstrate higher energy efficiency and lower energy requirements in de-ionizing low salinity waters.3, 4 In practical use, the efficiency of these systems can depend on various factors such as operating conditions, salinity of waters, occurrence of parasitic reactions, to name a few. Furthermore, the utility of deionization methods depends on their relative cost at materials, energy and lifecycle levels.
In this work, we first use an assessment of electrochemical deionization methods to emphasize the need for materials research to improve the viability of these processes. We then develop a framework to evaluate efficacy of electrode materials, in these systems. We discuss the advantages and disadvantages of both capacitive and faradaic electrode materials classes used in electrochemical deionization processes.
We demonstrate that solution composition largely influences the performance of each of these electrode materials classes. Specifically, the ion removal capacity and charge efficiency of these electrodes is influenced by solution composition. This reduction in performance results from a combination of several factors such as slow transport in the electrode, competing parasitic reactions or formation of surface films that reduce ion diffusion rates. Despite these challenges, the ion removal capacities achieved with faradaic electrodes often exceeds those offered by capacitive or pseudocapacitive materials. Finally, we propose alternatives such as proper selection of operating conditions, electrode structure and coatings to overcome some of the above-mentioned challenges and achieve improved removal of ions from complex water streams.
References

M. A. Anderson, A. L. Cudero and J. Palma, Electrochim. Acta, 55, 3845 (2010).

S. Porada, R. Zhao, A. van der Wal, V. Presser and P. M. Biesheuvel, Prog. Mater. Sci., 58, 1388 (2013).

J. Landon, X. Gao, J. K. Neathery and K. Liu, ECS Transactions, 53, 235 (2013).

Y. Oren, Desalination, 228, 10 (2008).
Exploration of Flash Sintering Mechanisms and Increase Mechanical Strength of YSZ for Dental Application
Authors: Chan Ho-Wei , Chen Hsun-Yi 
Published: February 2020

Flash sintering is a rapid ceramics sintering method with an external electric field assistance. Compared to conventional sintering by which YSZ should be heated to 1200~1400OC and hold for 2~4 hours to be sintered, flash sintering can lower the sintering temperature and shorten the sintering time markedly. In addition, the grain size of YSZ observed after flash sintering is often smaller than those sintered by conventional sintering approach. However, it is still not well understood how ceramics could be sintered in a few seconds and accompanied by a sudden increase of electric conductivity of the ceramic material. One proposed explanation of the electric field effect during flash sintering is the Joule heat generation within the sample, leading to significantly higher local temperature that in turn enhances mass transfer. However, the in-situ observed temperature of flash-sintered samples in literatures suggests a diffusion rate based on Arrhenius equation insufficient to meet the required mass transfer rate for rapid densification.
Flash sintering process is commonly divided into three stages. Stage I is considered an incubation time while a constant voltage is applied. Stage II is the period during which the flash event occurred, accompanied by a sharp increase of current. Stage III is the constant-current period after flash sintering when the pre-set limiting power is reached. In order to understand how electric field affects the sintering exactly, we performed flash sintering on 3YSZ compact and investigated the sample at the end of each aforementioned stages: case A, before the flash event; case B, at flash event and cut off the electric field instantly; case C, constant current mode for 300 s, as illustrated in figure (d). All of the samples are flash sintered at 850OC with an applied field of 150 V/cm and a current limit of 0.5 A.
SEM images are shown in figure (a), (b), and (c), which correspond to case A, B, and C, respectively. As shown in figure (a) and (b), very little grain growth is observed under constant voltage, and then grain growth accelerated after the flash event. If we extend the holding time of constant current period, as demonstrated in figure (c), the grain boundaries merging is more obvious and larger grain sizes are observed. However, too large a grain size of YSZ could lead to phase transformation from tetragonal to monoclinic structure and in turn reduce its mechanical strength. In this work, we focus on enlarging current limit and shorten holding time to sinter YSZ of smaller grain sizes and elevate uniformity of grain distribution by improving the electric contact. The goal is to raising the hardness of sintered YSZ to 1200 HV in Vickers hardness and density to 6 g/cm3 while controlling the proportion of phase transformation to be less than 5%. We aim to flash sinter YSZ of smaller grain size and higher mechanical strength for the dental application while reducing energy consumption during its manufacture.

Figure 1
Revealing the Dynamics of Single-Molecule Reactions in a Single-Molecule Nanoreactor
Authors: Qiu Kaipei , Yuan Bo , Zhang Wei-Wei , Wang Pei-Yao , Long Yi-Tao 
Published: February 2020

The dynamics of bond breaking and formation at the single-molecule level are of both fundamental importance and practical significance. Tremendous efforts have been made over the last decade toward the visualization of such transient phenomenon, with quite a few amazing single-molecule techniques being designed and developed [1-3]. However, it remains a major challenge to realize the truly single-molecule (cascade) reactions largely due to the stochastic nature of, e.g. molecular motions. Inspired by the enzymatic biosynthesis, the authors consider that a nanoscale confined space, or nanoreactor, must be essential to the highly ordered single-molecule reactions. Moreover, an ideal nanoreactor also needs to possess a well defined structure that is of comparable size to the individual reactant molecules. Hence, the rationally-mutated biological nanopores may be applied as a new brand of single-molecule nanoreactors, where the entry of reactants and exit of products are voltage-driven.
Herein, a mutant areolysin was adopted to study the unique confinement induced selectivity of nanopore reactor. In addition to regio- or stereo-selectivity, it is hypothesized that the mismatch between the bond formation kinetics of reactant molecules and their translocation speeds can offer an extra level of control on reaction selectivity. To prove this concept, the reaction dynamics of three constitutional isomers, 2-, 3-, and 4-mercaptobenzoic acid, at seven identical reaction sites (i.e. at the same position on each monomer) were examined in this work. Surprisingly, those tiny structural variations of three isomers could be easily distinguished by not only the different current blockades caused by each tethered molecule, but also the most frequent and prolonged current levels as well. This observation shed light on the transient dynamics of single-molecule reactions within a single-molecule nanoreactor, providing a crucial first step to the ultimate objective of 100% yield of targeted product at ambient conditions.

Scheme 1 Illustration of the single-molecule nanoreactor presented in this work, the mutant aerolysin nanopore.

Keywords: Single-Molecule Reactions, Single-Molecule Nanoreactor, Mutant Aerolysin Nanopore, Confinement Induced Selectivity, Electroanalytical Chemistry

References:

[1] D.G. de Oteyza, P. Gorman, Y.C. Chen, S. Wickenburg, A. Riss, D.J. Mowbray, G. Etkin, Z. Pedramrazi, H.-Z. Tsai, A. Rubio, M.F. Crommie and F.R. Fischer, Science 340 (2013): 1434.
[2] N.V. Voigt, T. Tørring, A. Rotaru, M.F. Jacobsen, J.B. Ravnsbæk, R. Subramani, W. Mamdouh, J. Kjems, A. Mokhir, F. Besenbacher and K.V. Gothelf, Nat. Nanotech. 5 (2010): 200.
[3] W. Xu, J.S. Kong, Y.-T.E. Yeh and P. Chen, Nat. Mater. 7 (2008): 992.

Figure 1
Graphene and Carbon Supported Manganese(IV)-Cobalt(II/III) Oxides Nanoparticles As High-Performance Electrochemical Supercapacitors
Authors: Jablonskiene Jolita , Vaičiūnienė Jūratė , Pakštas Vidas , Stalnionis Giedrius , Drabavičius Audrius , Jasulaitienė Vitalija , Tamašauskaitė-Tamašiūnaitė Loreta , Norkus Eugenijus 
Published: February 2020

The search for cleaner energy sources is required to shift focus to the generation of energy from electrochemical systems, batteries, fuel cells, solar cells, and super capacitors, among others. In this study we report a simple approach for preparation of the graphene (GR) and carbon (C) supported manganese(IV) and cobalt(II/III) oxides using microwave-assisted synthesis. The X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) methods were used for the characterization of morphology, structure and composition of the prepared the graphene and carbon supported MnO2-Co3O4 nanocomposites. Electrochemical performance of the MnO2-Co3O4/GR and MnO2-Co3O4/C nanocomposites was evaluated using long life cyclic voltammetry (CV) and galvanostatic charge-discharge.
The MnO2-Co3O4/GR and MnO2-Co3O4/C nanocomposites which have different morphologies, have been prepared by microwave synthesis. It was found that the graphene supported MnO2-Co3O4 nanoparticles has significant influence on the electrochemical performance of composites electrodes compared with that of the carbon supported MnO2-Co3O4 nanoparticles. The maximum specific capacitance was achieved at the MnO2-Co3O4/GR electrode in the 1 M Na2SO4 aqueous solution at the scan rate of 10 mV s-1. After 1000 charge/discharge cycles at the scan rate 100 mV s-1 the capacitance of all the materials synthesized in this study remains over 94 %, suggesting great potential for supercapacitors.
(Invited) Graphene for Bioapplications: Toxicological Studies and Integration in 3D-Scaffolds
Authors: Vazquez Ester 
Published: February 2020

The biological applications of graphene materials are strongly conditioned by the need to handle these nanostructures under physiological conditions, essentially complex aqueous media. While the water stabilization of Graphene Oxide (GO) can be easily achieved, this material do not possess the electrical properties of graphene. On the other hand, the mechanical exfoliation of graphite has led to the efficient separation and stabilization of graphene sheets in water when water-soluble dispersant species are used in the exfoliation process. However, many surfactants may cause toxicity problems if they are not thoroughly removed.
Our group has developed a facile and inexpensive ball milling process to exfoliate graphite and to prepare graphene dispersions in water. These aqueous suspensions can be freeze-dried, resulting in a soft powder that can be easily re-suspended in aqueous media, including cell culture media, at the desired concentration. We have also made sure that the redispersed solid retains the original properties of graphene.
During this talk, we will discuss (i) studies of interaction of so-prepared solutions with cells; (ii) the use of graphene in hybrid hydrogels for drug delivery purposes and for 3D cell culture media.
Oxygen-Doped Carbon Nanotubes for Near-Infrared Imaging Probes
Authors: Okazaki Toshiya 
Published: February 2020

Optical imaging is one of the most important techniques in biomedical studies. Recently, usage of near-infrared light has been extensively tried because of the higher transparency in biomaterials than the visible light. Single-walled carbon nanotubes (SWCNTs) are nanocarbon materials that show optical absorption and fluorescence in the near infrared (NIR) wavelength region. Especially, due to the bright fluorescence in NIR, SWCNTs have been expected as imaging probes.
In this talk, we show our recent results about the bio-application of oxygen-doped SWCNTs [1,2]. Interestingly, covalent doping of the nanotube surface with a low concentration of oxygen atoms can create a new optically allowed defect state [3]. Consequently, nanotube fluorescence is red-shifted and can be over 10 times brighter. Fluorescence vascular angiography and observation of the intestinal contractile activity of mice are demonstrated by using the produced oxygen-doped SWCNTs as infrared fluorescent labels and imaging agents [1]. Further, the biodistribution analysis after the administration of the oxygen-doped SWCNTs in mice is also discussed by the resonance Raman spectroscopy and NIR fluorescence microscopy [2].
[1] Y. Iizumi, M. Yudasaka, J. Kim, H. Sakakita, T. Takeuchi, T. Okazaki, Sci. Rep., 8, 6272 (2018).
[2] T. Takeuchi, Y. Iizumi, M. Yudasaka, S. Kondoh, T. Okazaki, in preparation.
[3] S. Ghosh, S. M. Bachilo, R. A. Simonette, K. M. Beckingham, R. B. Weisman, Science 330, 1656-1659 (2010).