bluuebunny/crossref_metadata_2025_split huggingface dataset:
First-Principles Study of the Crystal-Field and Racah Parameters of Cr3+ in Alumina
Authors: Ogasawara Kazuyoshi , Mishra Kailash C , Collins John 
Published: December 2020

The development of blue LEDs [1] enabled one to construct white LEDs by combining them with appropriate phosphors. Recently Mn4+-doped fluorides have been put into commercial use as the red phosphors for high color-rendering white LEDs [2]. However, in order to suppress the degradation due to high humidity and high temperature, a special surface treatment is required for these phosphors. Therefore, the search of other red phosphors activated by Mn4+ is still desired. For theoretical design of novel phosphors, non-empirical prediction of optical parameters such as the crystal-field and Racah parameters is quite important. The purpose of this study is to establish a first-principles approach to predict these parameters of transition metal ions in crystals.
In this work, the crystal-field and Racah parameters of ruby (Cr3+ doped α-Al2O3) were evaluated based on the first-principles calculations using the relationship between the ligand-field theory and the molecular orbital (MO) theory derived by Sambe and Felton [3]. Two types of first-principles methods were adopted. One is the discrete-variational (DV)-Xα method [4], which is an MO calculation method based on the one-electron approximation. The other is the discrete variational multi-electron (DVME) method [5], which is a configuration-interaction (CI) calculation method based on the explicit many-electron wave functions. The estimation of the crystal-field and Racah parameters were performed in the following three approaches.
(1) Estimation based only on the DV-Xα method
(2) Estimation based only on the DVME method
(3) Estimation based on the combination of the DVME method and the DV-Xα method
The results show that the values of the crystal-field and Racah parameters obtained by the approach (3) are in the best agreement with the values obtained by fitting to the experimental data [6], indicating that CI calculations using some corrections based on the one-electron MO calculations are effective for the non-empirical estimation of the crystal-field and Racah parameters [7]. These results also provide theoretical basis for the configuration-dependent correction and the correlation correction introduced in our previous CI calculations of ruby [5]. This approach could be applied to prediction of d-d transitions of Mn4+ in crystals to find a suitable host for novel Mn4+-activated red phosphors for white LEDs.
[1] I. Akasaki and H. Amano, Jpn. J. Appl. Phys. 45, 9001 (2006).
[2] J. E. Murphy, F. Garcia-Santamaria, A. A. Setlur, and S. Sista, SID 2015 DIGEST, 927 (2015).
[3] H. Sambe and R. Felton, Int. J. Quant. Chem., 10, 155 (1976).
[4] H. Adachi, M. Tsukada, and C. Satoko, J. Phys. Soc. Jpn. 45, 875 (1978).
[5] K. Ogasawara T. Ishii, I. Tanaka, and H. Adachi, Phys. Rev. B 61, 143 (2000).
[6] W. M. Fairbank, Jr., G. K. Klauminzer, and A. L. Schawlow, Phys. Rev. B 11, 60 (1975).
[7] K. Ogasawara, K.C. Mishra, and J. Collins, ECS J. Solid State Sci. Technol. 9, 016011 (2020).
Passivation to Improve the Efficiency and Reliability of III-Nitride Micro-Light-Emitting Diode
Authors: Lee Da , Seong Tae-Yeon , Amano Hiroshi 
Published: December 2020

Because group III-V and nitride-based micro light-emitting diodes (micro-LEDs) exhibit excellent performance, such as fast response, low power consumption, and thermal stability, they have been widely applied for display and biomedical applications, including optogenetics and multi-site neuron. However, unlike conventional LEDs (> 300 × 300 µm2), micro-LEDs (> 100 × 100 µm2) suffer from severe Shockley Read-Hall (SRH) non-radiative recombination, which is related to sidewall damage introduced by ICP-RIE dry-etching process for LED isolation. As the size of LEDs decreases, such non-radiative recombination phenomenon increases due to the increase in the sidewall surface ratio. Many attempts have been made to improve such defect-related recombination in micro-LEDs. In other words, sidewall passivation using dielectric materials was reported to be effective in alleviation sidewall-related leakage characteristics.
In this study, we investigated the electrical and optical properties of GaN-based micro-LEDs (blue) as a function of the number of passivation layers. The passivation layers were deposited using plasma enhanced chemical vapor deposition (PECVD) or/and atomic layer deposition (ALD). It is shown that by employing combined deposition techniques of ALD and PECVD, the optical and electric performance of 10 µm-size micro-LEDs are significantly improved. Compared with the conventional PECVD passivation method, the combined ALD/PECVD passivation showed the smaller ideality factor. For the 10 µm-size micro-LEDs, maximum external quantum efficiency (EQE) was obtained at 35 A/cm2 when the stacked ALD/PECVD passivation layer was used, whereas it was attained at 79 A/cm2 when the PECVD passivation was used. Based on the emission microscopy results, leakage paths were observed. The results show that the use of stacked ALD/PECVD passivation layer could serve as a potentially important process for the fabrication of high-performance micro-LEDs (< 10 × 10 µm2).
Electro-Oxidation of Oligosaccharides
Authors: Neha Neha , Coutanceau Christophe , Baranton Stève 
Published: December 2020

Keywords: electrocatalytic oxidation, glucose, methylglucoside, cellobiose, trehalose, electrolysis, platinum, bismuth, selectivity
Different catalysts (Pt/C, Pt9Bi1/C, Pt9Sn1/C, Pt7Ni3/C, Pt7Sn3/C and Pd3Au7/C) have been synthesized by a “water in oil” micro-emulsion method with nominal metal loading of 40 wt% and further characterised by physicochemical methods: thermogravimetric analysis, transmission electron microscopy, X-Ray diffraction, etc., to assess the metal loading, composition and size of nanoparticles. Linear scan voltammograms (Fig.1) have been performed to study the electrocatalytic behaviour of the catalysts towards electro-oxidation of glucose, methylglucoside, cellobiose and trehalose in 0.1 M NaOH as background electrolyte at 0.05 V s-1 scan rate. Pt9Bi1/C, most active one, leads to the lowest onset potentials of ca. 0.050 V, 0.100 V, 0.050 V and 0.200 V vs RHE for glucose, methylglucoside, cellobiose and trehalose oxidation respectively. To further gain an insight about the mechanism and species formed, in situ Fourier transform infrared spectroscopy has been used which demonstrated that in the case of glucose and methylglucoside oxidation, different reaction products were formed, i.e. gluconate and methyglucuronate, respectively1. In the case of cellobiose, a reducing disaccharide, transformation of C1 anomeric function to carboxylic acid occurred, while in the case of trehalose, a non-reducing disaccharide, mono and dicarboxylic acids were formed from C6 oxidation.
Chronoamperometry measurements were carried out for 6 hours in a 25 cm2 electrolysis cell with Pt9Bi1/C as anode catalyst for the electro-oxidation of 0.1 M glucose, methylglucoside, cellobiose and trehalose and Pt/C as cathode catalyst with simultaneous production of hydrogen at different potentials. The reaction products formed every hour for 6 hours were neutralized, identified and quantified by HPLC, MS and 1H and 13C NMR. At low cell voltages, high selectivity and significant conversion yields to monocarboxylic acids of these saccharides were obtained.

Acknowledgements: the authors gratefully acknowledge the INCREASE Federation (FR CNRS 3707), the technogreen chair, the European communities (FEDER) through the ECONAT project, the “Région Nouvelle Aquitaine” and the PEPS CNRS Energie for financial supports.

N. Neha, S. R. B. Kouamé, T. Rafaïdeen, S. Baranton, C. Coutanceau. Remarkably Efficient Carbon-Supported Nanostructured Platinum-Bismuth Catalysts for the Selective Electrooxidation of Glucose and Methyl-glucoside, Electrocatalysis (2020) DOI : 10.1007/s12678-020-00586-y.

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Use of TiO2-WO3 architecture for Photoelectrochemical Alcohol Oxidation
Authors: Hosseini Seyyedamirhossein , Peters Dennis G 
Published: December 2020

Ethanol, the major component of biofuel mixture, has significantly lower heat capacity compared to that of longer-chain alcohols such as butanol. As a result, oligomerization of ethanol has gained much attention. A three-step process that includes transition metal catalyzed C-alkylation was proposed for alcohol oligomerization. This cycle includes: (I) alcohol oxidation to the corresponding carboxylic acid, (II) dimerization via carboxylic acid terminals, and (III) further reduction of the oligomer to form the saturated alcohol. In this context, TEMPO has been vastly utilized for the electrochemical oxidation of alcohols. This process suffers from shortcomings such as limited turnover frequency of the reagent and small conversion yield of the synthesis. There have been some reports on the application of semiconductor electrodes for oxidizing certain types of alcohols. This approach, however, has shown some pitfalls such as high oxidation overpotential, low reaction yield, and low stability of the working electrode.
The goal of this research is to fabricate a novel photoanode for oxidizing alcohols to their corresponding carboxylic acids. In this work, we aimed at fabricating an architecture shown in Fig. 1. To prepare such an electrode, a 10 nm layer of Ti was first deposited over fused silica substrate via thermal deposition method. Then, TiO2 with thickness of 500-µm was deposited with application of sol-gel technique, and finally WO3 was loaded onto the TiO2 with application of controlled-potential pulse deposition. Our experimental results have shown that this electrode have great stability toward photoelectron corrosion and the yield of conversion is the function of the deposited tungsten oxide.

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Exploring the Synergistic Relationship between Organic Synthesis and Electrochemistry
Authors: Jing Qiwei , Moeller Kevin D 
Published: December 2020

Electrochemistry has long held potential as a tool for constructing organic molecules, and the organic chemistry community is both recognizing and impressively exploiting that potential with increasing regularity. Those efforts have taught us a great deal about how to think about electrochemical reactions, how to use the technique to accomplish new transformations that enrich the synthetic enterprise, and when to employ those methods.
Interestingly, the relationship between organic synthesis and electrochemistry can also be viewed in the opposite direction with the new synthetic chemistry being developed serving as a tool to facilitate and dramatically expand the scope of electrochemical methods. For example, new synthetic chemistry that allows for the site-selective generation of chemical reagents on an array have enabled the construction of complex, addressable molecular surfaces that can in turn be used to probe small molecule interactions with a variety of biological targets. The efforts set the stage for using microelectrode arrays as analytical devices for rapidly screening small molecule libraries in "real-time". The methods allow for the construction of libraries with tunable surfaces, careful control of surface concentrations, and previously unknown levels of quality control over the molecular library. The development of an even greater arsenal of synthetic tools for use on the arrays is underway, an effort that aims to expand the nature and size of the addressable libraries that can be used to probe the world around us.
Not surprisingly, the exploration of these new electrochemical tools is beginning to “give back” to the synthetic arena. A number of preparative scale synthetic applications have now arisen based on the concept of site-selective reagent generation. Chief among these is the use of paired electrochemical reactions for more sustainable reagent generation and the recent discovery that chemical reagents can be confined to specific regions within a preparative reaction; a development that potentially offers a new strategy for controlling the selectivity of a chemical reaction.
In the talk to be given, the interplay between organic synthesis and electrochemistry will be highlighted with a particular emphasis on how the interplay is shaping new avenues of research moving forward.
References:

For reviews see Moeller, K. D. Chem. Rev.
2018, 118, 4817-4833 and Jing, Q; Moeller, K. D. Accounts of Chem. Res.
2020,
53, 135-143.
(Invited) Electrochemical Dehydrogenative Cyclization Using a Halogen Mediator for the Synthesis of Thienoacene Derivatives
Authors: Suga Seiji , Mitsudo Koichi , Yonezawa Toki , Matsuo Ren 
Published: December 2020

The formation of carbon–sulfur bond is one of the fundamental and important transformations in organic synthesis because C–S bonds are abundant and important skeleton in the field of pharmaceuticals and material science. For example, the antidepressant vortioxetine, and an antifungal medication sertaconazole are useful medicines. π-Expanded benzo[b]thiophene derivatives, such as [1]benzothieno[3,2-b][1]benzothiophene (BTBT) and dinaphtho[2,3-b:2’,3’-d]thiophene (DNT), have received considerable attention as key building blocks for use in organic field effect transistors.
The electrochemical carbon–heteroatom bond formation is known to be as an environmentally benign strategy that proceeds under mild conditions. Recently, several novel electrochemical carbon–heteroatom coupling reactions, such as those for C–N and C–O, have been reported. For instance, Lin and co-workers reported the 1,2-diazidation of alkenes, and Baran reported electrochemical allylic oxidations. Lei reported electro-oxidative intermolecular C–S bond formation via C–H/S–H bond cleavage. Intramolecular dehydrogenative coupling between an arene and a thiocarbonyl group was also effective for constructing C–S bonds. While electrochemical transformations have been studied intensively, to the best of our knowledge, there has been no report on electrochemical carbon–heteroatom bond formation for the construction of π-expanded thienoacene derivatives, which are potent candidates for useful organic materials.
From this perspective, we are focusing on an electrochemical C–S bonds formation for the synthesis of thienoacene derivatives, such as [1]benzothieno[3,2-b]benzo[2,3-d]furan (BTBF) and [1]benzothieno[3,2-b]benzo[2,3-d]thiophene (BTBT). We first assumed that intramolecular dehydrogenative C–H/S–H coupling of 2-arylbenzene-1-thiol would form π-expanded thiophenes, but the desired product was not obtained. During the course of further study, we found that the desired dehydrogenative C–S bond formation proceeded smoothly in the presence of electrogenerated [Br+] as a promoter. This strategy was effective for the synthesis of π-expanded thienoacenes such as BTBF and BTBT. We report here the first electro-oxidative dehydrogenative C–S bond formation promoted by electrogenerated [Br+] for the synthesis of BTBFs and BTBTs.
[1] Koichi Mitsudo, Ren Matsuo, Toki Yonezawa, Haruka Inoue, Hiroki Mandai, Seiji Suga, Angew. Chem., Int. Ed.
2020, 59, 7803–7807.

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Realtime Transepithelial/Endothelial Electrical Resistance Measurements in Multiple Transwell Culture Inserts
Authors: Kaji Hirokazu , Raut Bibek , Hori Takeshi 
Published: December 2020

Epithelial and endothelial cells line the surface of the body. Adjacent cells of both epithelial and endothelial cells are connected to each other via intercellular junction called tight junction that regulates the diffusion of molecules and ions between the apical and basolateral side of the body. Quantification of this barrier is important to evaluate the suitability of in vitro cellular barrier models for drug toxicity or transport studies. Transepithelial/endothelial electrical resistance (TEER), a quantitative technique to access electrical resistance of the cellular monolayer during culture has become one of the most popular quantitative techniques to evaluate the integrity of tight junction. The major advantage of the TEER technique over traditional permeability measurements is that it is quick, label-free, and non-invasive. As such, the TEER technique has been widely used to evaluate in vitro models such as the blood-brain barrier, the intestine epithelial barrier, the alveolar epithelial barrier, and the blood-retina barrier.
However, the reported normalized TEER values of a specific cell type in transwell inserts are inconsistent between different research groups. A major cause of data variation is the manual technique that is used for measuring TEER. Typically, a “chopstick” like electrode pair is immersed inside a cell cultured semi-porous transwell insert membrane to measure TEER. Due to the variation in the alignment of the electrodes every time a TEER value is measured, the actual values vary significantly between measurements. A second problem with the conventional manual measurement process is time gap between each measurement (typically 12h or 24h) since a more frequent measurement requires frequent opening and closing of cell culture incubator door that can disturb the cells and introduce potential contamination.
Thus, to enable consistency in TEER measurement, and allow automated real-time data acquisition in multiple samples, we built an add-on device (used atop EVOM®, a commercially available TEER instrument) consisting of a 3D printed electrode holder, a temperature sensor, and a custom designed data logger. The 3D printed electrode holder allowed data variation to be minimized by allowing perfect alignment of electrodes during measurement. The real-time data acquisition and in-situ temperature measurement allowed detection and correction of data offset during medium replacement process. The concept and device demonstration presented here should enable research labs to minimize data variations allowing them to produce consistent TEER results without having to spend extra time manually measuring multiple samples.
(Invited) Glucose/Oxygen Wearable Biofuel Cells Based on Poly(glycidyl methacrylate)-Grafted MgO-Templated Porous Carbon
Authors: Shitanda Isao , Fujimura Yuki , Kato Takanao , Suzuki Ryo , Loew Noya , Hoshi Yoshinao , Watanabe Hikari , Itagaki Masayuki , Tsujimura Seiya 
Published: December 2020

There are a lot of recent researches on high power enzymatic glucose/O2 biofuel cells (BFCs). We have reported that the use of MgO-templated porous carbon (MgOC) at the electrodes of biofuel cells dramatically improves the output power [1-4]. Using MgOC can improve the effective electrode surface area, leading to increased current density and output density. Supporting enzymes on these types of porous materials is expected to lead to increased output density. In the past researches [1-4], the enzymes physically adsorbed inside the porous carbon gradually leach from the carbon surface after long-term operation or during the replacement of the fuel solution.
In this study, to prevent enzyme leakage, the enzyme or mediator were immobilized on the MgOC surface via multipoint covalent bonding; the grafting of polymers bearing pendant glycidyl groups was achieved by the polymerization of glycidyl methacrylate (GMA), initiated by electron beam irradiation on the carbon surface. Poly(glycidyl methacrylate) (poly(GMA)) bearing pendant glycidyl groups, grafted on the surface of MgO-templated carbon, is useful for forming strong multipoint covalent bonds with amino functional groups on the surface of flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH), Azure A and aminoferrocene.
For example, the immobilized FAD-GDH can generate glucose-oxidation catalytic current using 1,2-naphthoquinone (12NQ) as the redox mediator, which is also captured on the electrode surface. The catalytic current is more stable than that obtained using the FAD-GDH-MgOC electrode without poly(GMA) because the leaching of FAD-GDH and 12NQ is suppressed by the enzyme capping effect.
The BFC performance using the anode measured in 1.0 M phosphate buffer (PBS) containing 100 mM glucose exhibited the open circuit voltage of 0.8 V, maximum power density of 1.4 mW/cm2, and maximum current density of 4.25 mA/cm2.
In the present paper, we totally discuss three types glucose/oxygen biofuel cells based on the poly(glycidyl methacrylate)-grafted MgO-templated porous carbon.

References

[1] S. Tsujimura et al., Electrochemistry 83 (2015) 372.
[2] I. Shitanda et al., Electrochemistry, 83 (2015) 329.
[3] I. Shitanda et al., Journal of Electrochemical Society, 166 (2019) B1063.
[4] I. Shitanda et al., Journal of Power Sources, 436 (2019) 226844.

Acknowledgement

This work was partially supported by JST-ASTEP Grant Number JPMJTS1513, JSPS Grant Number 17H02162 and Private University Research Branding Project (2017-2019) from Ministry of Education, Culture, Sports, Science and Technology, and Tokyo University of Science Grant for President's Research Promotion．
(Invited) Peptide Screening for the Regulation of Gold Nano-Biomineralization Using Peptide Array Technology
Authors: Tanaka Masayoshi 
Published: December 2020

Some peptides have been utilized in the functionalization of nanomaterials, the control of nanoparticle (NP) synthesis, as biotemplating for morphological control, and biocatalysts for the NP crystallization. The catalytic peptides used for NP synthesis, named biomineralisation peptides, generally demonstrate high specific binding to a target material, and are screened from a peptide library (e.g. phage display library). However, the properties of NPs synthesized, using such biomineralization peptides, cannot be predicted from screening process; thus the development of a rational peptide screening method which can be used to synthesize NPs with specific morphological and optical properties would greatly expand the potential of biomineralization peptides.
Herein, we focused on gold, which is also used as an electrode material for sensors, and developed an efficient method for identifying peptides that bind to gold nanoparticles (AuNPs). Using the spot synthesis-based peptide array technique, AuNP binding activities of approximately 1,800 peptides were firstly evaluated and revealed various activities ranging from positive (high-affinity binding peptides) to negative (weak- or null-affinity binding peptides). Among 50 peptides showing the highest AuNP binding activity, 46 sequences showed the presence of tryptophan-based motifs including W[Xn]W, H[Xn]W, and W[Xn]H (W: tryptophan, X: any amino acid, n: 1 to 8 amino acid residues), whereas none of these motifs was found in the WORST50 peptides. Notably, by using peptide array comprising high-binding peptides, more than 100 sequences were discovered at once to have AuNP synthetic ability on the peptide array. In addition, the image analysis of peptide array disclosed the optical property information from synthesized AuNPs at each peptide spot. Subsequently, screened peptides were demonstrated as suitable agents for the one-pot aqueous-phase synthesis of AuNPs and optical properties shown in the solution were consistent with that of array. Furthermore, obtained AuNPs were characterized to three types regarding to their optical properties, which are red, green and blue. The particle sizes were around 8.9, 2.6 and 34.7 nm respectively. These techniques are show potential not only in improved AuNP biomineralizations, but also could be used in the synthesis of other inorganic nanomaterials, such as semiconductor and magnetic particles in ambient condition. In this talk, I will also present some research examples using peptide array technology for biosensor development.

References

Tanaka, M., et al., (2017) Acta Biomaterialia, 49, 495-506.

Tanaka, M., et al., (2019) Nanoscale Adv., 1, 71-75.

Tanaka, M., et al., (2020) Int. J. Mol. Sci., 21(7), 2377

Komikawa, T., et al., (2020) Biosens. Bioelectron., 153, p112030

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