bluuebunny/crossref_metadata_2025 huggingface dataset:
Lived experience of pedagogical boomerang in mathematics teaching-learning
Authors: Rawat Sher Singh , Luitel Bal Chandra , Belbase Shashidhar
Published: March 2021

The purpose of this study was to explore the critical life-events of the first author's journey of learning and teaching mathematics that prompted critical thinking about his past experiences as a student and teacher. It portrays a paradigmatic shift from a traditionalist thinker to a constructivist actor in the classroom from the critical life-events within and out of classroom experiences by using autoethnography as the writing and research genre by connecting his personal experiences in the social, cultural, and teaching/learning contexts of Nepal. The major themes emerged from the autoethnography were-- Thinking Narratively: Joining a School and Dropping Out; Thinking Narratively: Back to School and Dropping In; Thinking Interpretively: Dropping out of School; Thinking Poetically: Dropping in School; and Nightmare of the First Teaching: A Pedagogical Boomerang. These themes portrayed a pedagogical boomerang in learning and teaching mathematics from a remote village in Western Nepal to the neighborhood of the capital city Kathmandu.
How far have we gone? Integration of intercultural language learning principles in Philippine ESL classrooms
Authors: Ayunon Chirbet Cariño , Haloc Lysel Ildefonso
Published: March 2021

Intercultural education is firmly rooted on the notion that language and culture are intrinsically linked. Several studies have looked into the importance of understanding different languages and cultures in language teaching; however, studies on the integration of principles intercultural language learning (IcLL) in Philippine ESL classrooms seem to be lacking. This is what the article addresses as it looked into the extent of integration of IcLL principles in two higher educational institution in Region 2, Cagayan Valley, Northern Philippines. Anchored on the principles of IcLL and through the employment of survey to elicit responses of the language teachers as to the integration of IcLL principles in language classrooms, results revealed that teachers perceive IcLL to be integrated in their classrooms to a great extent. Specifically, the principles of active construction and social interaction are integrated to a very high extent while the principles making connections, reflection, and responsibility were perceived to be integrated to a high extent. As regards classroom activities, the teachers favored the employment of discussions, lectures, writing tasks, oral reports, role plays, small group tasks, simulations or skits and collaborative learning activities in transmitting the target culture.
The Development of Values Education under the Integrated Learning Subject in the Philippines: Islamic Concepts and Peace Building
Authors: Nagahama Hirofumi
Published: March 2021

This research on the Philippine values education clarifies how much their understandings on values have been diversified, especially between Christians and Muslims.
Grammar Consciousness-Raising Activities and Iranian EFL Learners' Attitudes toward English Language
Authors: Heidari Farrokhlagha , Mansourzadeh Nurullah
Published: March 2021

The first purpose of this study was to investigate the effect of consciousness-raising (C-R) activities on learning grammatical structures by Iranian EFL learners. The second one was to investigate the effect of gender through C-R activities and tasks. Finally, this study wanted to investigate the Iranian students’ attitudes toward learning English prior to and after applying the C-R activities. An attitude questionnaire was use to investigate the participants' attitudes toward learning English before and after applying C-R activities. Data analysis indicated that using C-R activities in is significantly more effective than the traditional approaches. Regarding gender, male outperformed females. Therefore, it is recommended that other teachers consider C-R activities as useful options in teaching other aspects of language. Based on the statistics and findings, Iranian students’ attitudes toward learning English language were not much different prior to and after applying C-R activities.
Direct Cardiac Actions of the Sodium Glucose Co‐Transporter 2 Inhibitor Empagliflozin Improve Myocardial Oxidative Phosphorylation and Attenuate Pressure‐Overload Heart Failure
Authors: Li Xuan , Lu Qingguo , Qiu Yunguang , do Carmo Jussara M. , Wang Zhen , da Silva Alexandre A. , Mouton Alan , Omoto Ana C. M. , Hall Michael E. , Li Ji , Hall John E.
Published: March 2021

Background

We determined if the sodium glucose co‐transporter 2 inhibitor empagliflozin attenuates pressure overload‐induced heart failure in non‐diabetic mellitus mice by direct cardiac effects and the mechanisms involved.

Methods and Results

Male C57BL/6J mice (4–6 months of age) were subjected to sham surgeries or transverse aortic constriction to produce cardiac pressure overload. Two weeks after transverse aortic constriction, empagliflozin (10 mg/kg per day) or vehicle was administered daily for 4 weeks. Empagliflozin increased survival rate and significantly attenuated adverse left ventricle remodeling and cardiac fibrosis after transverse aortic constriction. Empagliflozin also attenuated left ventricular systolic and diastolic dysfunction, evaluated by echocardiography, and increased exercise endurance by 36% in mice with transverse aortic constriction‐induced heart failure. Empagliflozin significantly increased glucose and fatty acid oxidation in failing hearts, while reducing glycolysis. These beneficial cardiac effects of empagliflozin occurred despite no significant changes in fasting blood glucose, body weight, or daily urine volume. In vitro experiments in isolated cardiomyocytes indicated that empagliflozin had direct effects to improve cardiomyocyte contractility and calcium transients. Importantly, molecular docking analysis and isolated perfused heart experiments indicated that empagliflozin can bind cardiac glucose transporters to reduce glycolysis, restore activation of adenosine monophosphate‐activated protein kinase and inhibit activation of the mammalian target of rapamycin complex 1 pathway.

Conclusions

Our study demonstrates that empagliflozin may directly bind glucose transporters to reduce glycolysis, rebalance coupling between glycolysis and oxidative phosphorylation, and regulate the adenosine monophosphate‐activated protein kinase mammalian target of rapamycin complex 1 pathway to attenuate adverse cardiac remodeling and progression of heart failure induced by pressure‐overload in non‐diabetic mellitus mice.
Mission Impossible: Karl Neufeld’s Holy War Propaganda Trip to Medina (1915)
Authors: Strohmeier Martin
Published: March 2021

This article deals with Karl Neufeld’s trip to Medina, undertaken in the framework of German efforts to incite insurrections with the aim of destabilizing British rule in the Muslim world. His specific task was to spread propaganda in the Hijaz and the Sudan; he made it only to Medina, from where he was expelled by the Ottoman government after a stay of six weeks. Neufeld’s diary on which this article is mainly based is the only source about how Holy War propaganda was actually disseminated. Therefore, it goes beyond the existing literature and adds new insight into the discussion of German expeditions organized to counter British influence in the Middle East during the First World War. In contrast to most of the other enterprises, Neufeld accomplished certain goals, which does not, however, change the overall picture that the “jihād made in Germany” was a failure.

Materials used include files from the archive of the German Foreign Office (Politisches Archiv, Auswärtiges Amt: pa-aa), the Sudan Archive Durham (Durham University Library: sad), and narrative sources, as well as the pertinent research literature.
The Normativity of Musical Works
Authors: Arbo Alessandro
Published: March 2021

The cases of copyright infringement that occasionally crop up in the world of music raise many interesting questions: what do we mean when we talk about the identity of a musical work and what does such an identity involve? What in fact are the properties that make it something worth protecting and preserving? These issues are not only of legal relevance, they are central to a philosophical discipline that has seen considerable advances over the last few decades: musical ontology. Taking into account its main theoretical models, this essay argues that an understanding of the ontological status of musical works should acknowledge the irreducible ambivalence of music as an “art of the trace” and as a “performative art.” It advocates a theory of the musical work as a “social object” and, more specifically, as a sound artefact that functions aesthetically and which is based on a trace informed by a normative value. Such a normativity is further explored in relation to three primary ways of conceiving and fixing the trace: orality, notation and phonography.
Review of the leucotela species-group of Conura (Hymenoptera: Chalcididae) from Amazon rainforest
Authors: DE AGUIAR BROTTO THALES RENAN , TAVARES MARCELO TEIXEIRA
Published: March 2021

The leucotela species-group of Conura Spinola (Hymenoptera: Chalcididae) was initially proposed to include C. leucotela (Walker 1862) within the subgenus Spilochalcis Thomson. Despite this treatment, the accurate identification of C. leucotela is not possible based on the literature. In this paper, C. leucotela is redescribed and two new species, C. paraleucotela sp. nov. and C. pseudoleucotela sp. nov., are described within the leucotela group, with all the species based on female singletons. Additionally, diagnoses and illustrations are presented for two other unnamed species based on males. The taxonomic concept of the species group is discussed, and new diagnostic characters are proposed. An identification key and illustration of species are provided. The morphology of the coupling mechanism of the propodeum and gaster of some species of the leucotela group and its relation with possible hosts is discussed. A short discussion of rarity of the leucotela group is presented.
A new species of genus Homoeoxipha Saussure, 1874 from China (Orthoptera: Trigonidiidae: Trigonidiinae)
Authors: LI SHI-YU , PENG HUI-LING , SHEN CHU-ZE , HE ZHU-QING
Published: March 2021

The genus Homoeoxipha contains 11 species worldwide with 4 recorded from China. In this study, we reconstructed the gene tree based on COI gene, and reported one new species, H. oscillantenna He sp. nov. The new species is similar to H. eurylobus Ma, Liu & Zhang, but differs in the color of fore femur and the structure of male genitalia. Calling songs and nymph morphology are also provided. The type specimens are deposited in the Museum of Biology, East China Normal University (ECNU).
Two new species of the genus Odochilus Harold, 1877 (Coleoptera: Scarabaeidae: Aphodiinae: Odochilini)
Authors: RAKOVIČ MILOSLAV , ANICHTCHENKO ALEXANDER
Published: March 2021

Two new species of the genus Odochilus Harold, 1877 (Coleoptera: Scarabaeidae: Aphodiinae: Odochilini) from the Oriental Region are described as follows: O. shavrini Rakovič & Anichtchenko, new species from the Philippines (Mindanao) and O. borneensis Rakovič & Anichtchenko, new species from Malaysia (Sarawak). Photographs of their habitus are presented. Differential diagnoses are mentioned.
Bioactivity Improvement of Zirconia Substrate by Hydroxyapatite Coating Using Room Temperature Spray Processing
Authors: Kim Jeong Jun , Lee Jong Kook
Published: March 2021

Zirconia ceramics has a bioinert property with low bioactivity. So, it is necessary to improve its low bioactivity by the surface modification using effective coating methods. In this study, we fabricated the hydroxyapatite-coated zirconia substrate by room temperature spray processing
to improve the bioactivity of the zirconia implant and investigated its coating effect on the biological performance of zirconia substrate via an in vitro test in simulated body fluid (SBF) solution. Before the room temperature spray coating was completed, size-controlled hydroxyapatite
powder that had an average size of 4.5 μm, was obtained by the calcination and milling of a commercial powder. By controlling the processing parameters, such as spraying distance, and deposition cycles, we fabricated homogeneous and dense hydroxyapatite coatings on zirconia substrate.
Surface morphology, coating thickness, and microstructure were dependent on deposition cycles, and were related to surface roughness and bioactivity. Zirconia substrates with wave-patterned and roughened hydroxyapatite coatings demonstrated high bioactivity in their in vitro tests.
Via the immersion test in an SBF solution, surface dissolution and new precipitates of hydroxyapatite were observed on coated zirconia substrate, indicating the degree of bioactivity.
Sol–Gel Coating of Hydroxyapatite on Zirconia Substrate
Authors: Yun Yu Hyeon , Lee Jong Kook
Published: March 2021

The zirconia used in dental implants requires excellent mechanical and chemical properties such as high strength, high biological performance, corrosion resistance, and phase stability. In this study, after we prepared a highly fluidized solution of calcium phosphate, we fabricated
a hydroxyapatite (HA) coating layer on a zirconia substrate using the sol–gel method to enhance its biocompatibility and bone-bonding ability. We dipped the zirconia substrate into the calcium phosphate sol to obtain the HA-coated film, which was dried at room temperature. The phase
change and microstructural evolution were examined while the coating dried and during heat treatment. The biological activity of the coated and as-received substrates was evaluated using an in vitro experiment and the results were compared. The HA-coated film showed a highly dense and
uniform layer structure, while its physical and biological properties depended on the starting substrate, coating times, and processing conditions.
Passband-Flattened Frequency-Tunable Optical Fiber Multiwavelength Filter with Composite Combination of Waveplates
Authors: Jung Jaehoon , Lee Yong Wook
Published: March 2021

We propose a passband-flattened frequency-tunable optical multiwavelength filter with a composite combination of waveplates, which is realized by harnessing a polarization-diversified loop structure. The proposed filter comprises a polarization beam splitter (PBS), two polarization-maintaining
fiber (PMF) segments of equal length, an ordered waveplate combination (OWC) of a half-wave plate (HWP) and a quarter-wave plate (QWP) before the first PMF segment, and an OWC of a QWP and an HWP before the second PMF segment. The second PMF segment is butt-coupled to one port of the PBS so
that its slow axis is oriented at 22.5° for the horizontal axis of the PBS. Based on the filter transmittance derived through the Jones calculus, we found the orientation angle (OA) sets of the four waveplates, which could induce an extra phase shift Φ from 0° to 360°
in the passband-flattened transmittance function. From the transmission spectra calculated at the eight selected OA sets, which caused Φ to increase from 0° to 315° by steps of 45°, it was confirmed that the passband-flattened multiwavelength spectrum can be continuously
tuned by properly controlling the OAs. This indicates continuous wavelength tunability based on composite OWCs. Then, this theoretical prediction was verified by experimental demonstration.
Optical Analysis of Hole Patterned Ag Nanoparticle Structure
Authors: Jeon Hyun-Ji , Kim Ji-Yeon , Choi Jinnil
Published: March 2021

A structure with periodic sub-wavelength nanohole patterns interacts with incident light and causes extraordinary optical transmission (EOT), with metal nanoparticles leading to localized surface plasmon resonance (LSPR) phenomena. To explore the effects of metal nanoparticles (NPs),
optical analysis is performed for metal NP layers with periodic hole patterns. Investigation of Ag NP arrangements and comparisons with metal film structures are presented. Ag NP structures with different hole configuration are explored. Also, the effects of increasing light incident angle
are investigated for metal NP structures where EOT peak at 460 nm wavelength is observed. Moreover, electric field distributions at each transmittance peak wavelengths and optical noise are analyzed. As a result, optical characteristics of metal NP structures are obtained and differences in
resonance at each wavelength are highlighted.
Characteristics of Self-Nanostructured Growth of 4,6-Bis(3,5-di(pyridin-3-yl)phenyl)-2-Methylpyrimidine (B3PyMPM)
Authors: Bae Eun Jeong , Baek Dong-Hyun , Park Young Wook
Published: March 2021

In this study, we report the self-nanostructured growth of 4,6-bis(3,5-di(pyridin-3-yl)phenyl)-2-methylpyrimidine (B3PyMPM), which is widely used as an electron transport layer for organic light-emitting diodes (OLEDs). B3PyMPM nanostructures were formed on the surface of a substrate
using vacuum thermal evaporation, and parameters such as substrate rotation speed and evaporation angle were altered to study their effect on the growth of nanostructures. Moreover, it was proven that the growth of nanostructures was dependent on the underneath materials. This self-nanostructured
growth of B3PyMPM would affect the outcoupling and the efficiency improvement of OLEDs.
Effect of Threshold Voltage Window and Variation of Organic Synaptic Transistor for Neuromorphic System
Authors: Hwang Yeongjin , Jeon Jeong Hoon , Lee Juhyun , Yoon Jonghyuk , Kim Felix Sunjoo , Kim Hyungjin
Published: March 2021

Synaptic devices, which are considered as one of the most important components of neuromorphic system, require a memory effect to store weight values, a high integrity for compact system, and a wide window to guarantee an accurate programming between each weight level. In this regard,
memristive devices such as resistive random access memory (RRAM) and phase change memory (PCM) have been intensely studied; however, these devices have quite high current-level despite their state, which would be an issue if a deep and massive neural network is implemented with these devices
since a large amount of current-sum needs to flow through a single electrode line. Organic transistor is one of the potential candidates as synaptic device owing to flexibility and a low current drivability for low power consumption during inference. In this paper, we investigate the performance
and power consumption of neuromorphic system composed of organic synaptic transistors conducting a pattern recognition simulation with MNIST handwritten digit data set. It is analyzed according to threshold voltage (VT) window, device variation, and the number of available
states. The classification accuracy is not affected by VT window if the device variation is not considered, but the current sum ratio between answer node and the rest 9 nodes varies. In contrast, the accuracy is significantly degraded as increasing the device variation; however,
the classification rate is less affected when the number of device states is fewer.
Effect of Electrode Materials on the Electrical Characteristics of Amorphous Indium-Tin-Gallium-Zinc Oxide Thin-Film Transistors
Authors: Lee Hosang , Cho Kyoungah , Kim Sangsig
Published: March 2021

In this study, we investigated the effect of electrode materials on the electrical characteristics of coplanar top-gate a-ITGZO thin-film transistors, in which the gate, source, and drain electrodes were made of the same metal, Ti or Al. The field-effect mobilities of the a-ITGZO thin-film
transistors with Ti and Al electrodes were 35.2 and 20.1 cm2/V·s, respectively, and the threshold voltage of the a-ITGZO thin-film transistor with Ti electrodes was −0.4 V, whereas that of the transistor with Al electrodes was −1.8; this shift is attributed to
the fact that Ti has a higher work function than Al. When Ti was used as the source and drain electrode material, the channel resistance and effective channel length were reduced owing to the penetration of metal atoms into the channel region from the edge of the source/drain electrodes.
Highly Efficient 7,7-Dimethyl-9-(10-phenylanthracen-9-yl)-7H-Benzo[6,7]Indeno[1,2-f]Quinoline Derivatives for Blue Fluorescent Organic Light-Emitting Diodes
Authors: Han Ju Hee , Park Jinho , Han Giwoong , Kim Ki Ju , Lee Hakjun , Kim Young Kwan , Yoon Seung Soo
Published: March 2021

Highly efficient blue fluorescent 7,7-dimethyl-9-(10-phenylanthracen-9-yl)-7H-benzo[6,7]indeno[1,2- f]quinoline derivatives, based on benzo-indeno-quinoline and phenylanthracene were designed and synthesized. To test their electroluminescent properties, organic light-emitting diodes
(OLEDs) were fabricated with the configuration of indium-tin-oxide (ITO) (150 nm)/4,4′,4″-Tris[2- naphthyl(phenyl)amino]triphenylamine (2-TNATA) (30 nm)/N,N′-di(1-naphthyl)-N,N′-diphenyl-1,1′- biphenyl)4,4′-diamine (NPB) (20 nm)/blue emitting materials (20
nm)/bathophenanthroline (Bphen) (30 nm)/Liq (2 nm)/Al (100 nm). The devices using these blue materials as emitters showed efficient blue emission. Particularly, a device employing 7,7-dimethyl-9-(10-phenylanthracen-9-yl)-7Hbenzo[ 6,7]indeno[1,2-f]quinoline as an emitting layer yielded the
best performance with a luminous efficiency (LE), power efficiency (PE), and external quantum efficiency (EQE) and the Commission International de L’Eclairge (CIE) coordinates of 4.60 cd/A, 3.07 lm/W, 4.32% at 20 mA/cm2, and (0.16, 0.12) at 8.0 V, respectively.
Simultaneous Measurement of Torsion and Temperature Based on π-Phase-Shifted Long-Period Fiber Grating Inscribed on Double-Clad Fiber
Authors: Han Jinsil , Kim Jihoon , Lee Seul-Lee , Choi Sungwook , Lee Yong Wook
Published: March 2021

In this work, we experimentally demonstrated an optical fiber sensor capable of performing simultaneous measurement of torsion and temperature using a π-phase-shifted long-period fiber grating (LPFG) inscribed on double-clad fiber (DCF), referred to as a PS-DC-LPFG. The fabricated
PSDC- LPFG showed split attenuation bands near its resonance wavelength, and the two dips in these bands were selected as sensor indicators, denoted as Dips A and B, for the simultaneous measurement of torsion and temperature. The torsion and temperature responses of the two indicators were
investigated in a twist angle range from −360° to 360° and a temperature range from 30 to 120 °C, respectively. When the twist angle increased from 0° to 360° (clockwise) at room temperature, both Dips A and B showed redshifts. On the contrary, when the twist angle
decreased from 0° to −360° (counterclockwise), the two dips showed blueshifts. In terms of temperature responses, both dips showed redshifts with increasing ambient temperature while the sensor head (i.e., the PS-DC-LPFG) remained straight without any applied torsion. Owing to
their linear and independent responses to torsion and temperature, the changes in torsion and temperature applied to the PSDC- LPFG could be simultaneously estimated from the measured wavelength shifts and calculated sensitivities of the two indicator dips.
Ge Solar Cells with Micro-Rod Arrays: Structural and Optical Properties
Authors: Yun Yeojun , Kim Kangho , Lee Jaejin
Published: March 2021

Ge single-junction solar cell structures are grown on micro-patterned Ge substrates using lowpressure metalorganic chemical vapor deposition. 300 nm high micro-rod arrays are formed on the p-Ge substrates using photolithography and dry etching techniques. The micro-rod arrays
are designed with rod diameter varying from 5 to 15 μm and arranged in a hexagonal geometry with rod spacing varying from 2 to 12 μm. Ge p–n junction structures are fabricated by phosphorus atomic diffusion process on the micro-patterned Ge substrates. 100
nm thick InGaP window and 300 nm thick GaAs cap layers are grown to reduce the surface recombination and the ohmic contact resistivity, respectively. Our results indicate that the micro-rod structures improve the performance of the Ge solar cells. An improvement of 16.1% in the photocurrent
of the Ge micro-rod solar cell is observed compared to that of a reference Ge solar cell with planar surface. The improvement in the short circuit current density can be attributed to the light trapping effect, enlarged p–n junction area, and enhanced carrier collection efficiency.
As a result, the conversion efficiency of the Ge solar cell with micro-rod arrays (5 μm diameter, 2 μm spacing, and 300 nm height) is improved from 3.84 to 4.78% under 1 sun AM 1.5G conditions.
Overgrowth of Single Crystal Diamond Using Defect-Selective Etching and Epitaxy Technique in Chemical Vapor Deposition
Authors: Lee Jonggeon , Kwak Taemyung , Yoo Geunho , Kim Seongwoo , Nam Okhyun
Published: March 2021

In this study, we demonstrated the defect-selective etching and epitaxy technique for defect reduction of a heteroepitaxial chemical vapor deposition (CVD) diamond substrate. First, an 8 nm layer of nickel was deposited on the diamond surface using an e-beam evaporator. Then, defect-selective
etching was conducted through an in situ single process using microwave plasma chemical vapor deposition (MPCVD). After defect-selective etching, the diamond layer was overgrown by MPCVD. The defect density measured from the atomic force microscope image decreased from 3.27×108
to 2.02×108 cm−2. The first-order Raman peak of diamond shifted from 1340 to 1336 cm−1, and the full width at half maximum (FWHM) decreased from 9.66 to 7.66 cm−1. Through the defect-selective etching and epitaxy technique,
it was confirmed that the compressive stress was reduced and the crystal quality improved.
Demonstration of TiO2 Based Ultra High-k (k = 30) Metal-Insulator–Semiconductor Capacitor and Its Electrical Properties
Authors: Kang Bohyeon , Choi Kyeong-Keun , An Jehyun , Baek Rock-Hyun
Published: March 2021

In this paper, we investigated TiO2 as gate dielectric to achieve the large dielectric constant. The ultra high-k value over 30 was obtained by Capacitance–Voltage measurement of Al/Ti/TiO2/Si Metal-Insulator–Semiconductor (MIS) capacitor. Among
as deposited, rapid thermal annealing (RTA) at 750 °C and 1000 °C, the RTA at 750 °C showed the lowest gate leakage current. It implies that TiO2 has optimum RTA temperature having the lowest leakage current. When TiO2 is annealed at 750 °C, the phase
of TiO2 changes to anatase and interfacial layer between TiOx and Si was formed. While TiO2 is annealed at 1000 °C, the phase of TiO2 changes to rutile and diffusion of silicon atoms was clearly observed and it causes the silicide formation. Based on measurement
data, we proposed the energy band diagram of Al/TiO2/Si MIS capacitors. This diagram shows that the energy band gap of RTA at 750 °C is expanded while that of RTA at 1000 °C is contracted. In addition, TiO2 with RTA at 550 °C was tested to confirm leakage
current and it shows lower leakage current than RTA at 750 °C as we expected. This result confirmed that optimum RTA temperature of TiO2 would exist under 750 °C.
Thermal Behavior of an AlGaN/GaN-Based Schottky Barrier Diode on Diamond and Silicon Substrates
Authors: Kim Zin-Sig , Lee Hyung-Seok , Bae Sung-Bum , Ahn Hokyun , Lee Sang-Heung , Lim Jong-Won , Kang Dong Min
Published: March 2021

Devices based on AlGaN/GaN heterostructures, for example, Schottky barrier diodes (SBDs) and high electron mobility transistors (HEMTs), have been intensively investigated for applications to high-frequency and high-power areas. Presently, the substrates widely distributed are AlGaN/GaN
on SiC for its high performance in radio frequency (RF) applications, for examples high cutoff frequency (fT) or high maximum oscillation frequency (fmax), and AlGaN/GaN on Si for its high power performance, for examples high breakdown voltage or high voltage
operation. Chemical vapor deposition (CVD) diamond substrates have a thermal conductivity of 12 W/cm·K, and this is a remarkable point because HEMTs or SBDs on AlGaN/GaN on CVD diamonds are one of the promising alternatives for power and RF applications. In comparison, the thermal conductivity
of AlGaN/GaN on a sapphire substrate is 0.33 W/cm·K while that of AlGaN/GaN on a Si substrate is 1.3 W/cm·K and that of AlGaN/GaN on a SiC substrate is 4.9 W/cm·K. In this work, we fabricated SBDs with a 137 mm Schottky channel length on AlGaN/GaN on Si and also on a CVD
diamond substrate. We also compared the thermal behaviors of these fabricated large scale SBDs on Si and a CVD diamond substrate.
Study on Cyclic Compressive and Dynamic Mechanical Properties of Porous Polyurethane Composites Prepared with Hollow Silica Microspheres
Authors: Kwak Bomin , Kwon Younghwan
Published: March 2021

Porous polycaprolactone-based polyurethane composites containing hollow silica microspheres were synthesized by one-step bulk polymerization. The effects of incorporated hollow silica microspheres on the cyclic compressive and dynamic mechanical properties of the composites were examined.
Cyclic compression testing was carried out to record the accumulated stress versus strain profiles during 100 continuous loading and unloading cycles and to study the compressive behavior and time-dependent recovery of the composites. The effects of frequency on the dynamic mechanical properties
of the composites was also investigated using a dynamic mechanical analyzer. Cole–Cole and Wicket plots were drawn to check the validity of the time-temperature supposition of the composites in the temperature and frequency ranges considered. Master curves of the composites were constructed
based on the time-temperature superposition principle to obtain the long-term dynamic mechanical behavior of the composites.
Addition of Cellulose Nanofibers to Control Surface Roughness for Hydrophobic Ceramic Coatings
Authors: Shin Eun Ae , Kim Gye Hyeon , Jung Jeyoung , Lee Sang Bong , Lee Chang Kee
Published: March 2021

Hydrophobic ceramic coatings are used for a variety of applications. Generally, hydrophobic coating surfaces are obtained by reducing the surface energy of the coating material or by forming a highly textured surface. Reducing the surface energy of the coating material requires additional
costs and processing and changes the surface properties of the ceramic coating. In this study, we introduce a simple method to improve the hydrophobicity of ceramic coatings by implementing a textured surface without chemical modification of the surface. The ceramic coating solution was first
prepared by adding cellulose nanofibers (CNFs) and then applied to a polypropylene (PP) substrate. The surface roughness increased as the amount of added CNFs increased, increasing the water contact angle of the surface. When the amount of CNFs added was corresponding to 10% of the solid content,
the surface roughness average of the area was 43.8 μm. This is an increase of approximately 140% from 3.1 μm (the value of the surface roughness of the surface without added CNFs). In addition, the water contact angle of the coating with added CNF increased to 145.0°,
which was 46% higher than that without the CNFs. The hydrophobicity of ceramic coatings with added CNFs was better because of changes in the surface topography. After coating and drying, the CNFs randomly accumulated inside the ceramic coating layer, forming a textured surface. Thus, hydrophobicity
was improved by implementing a rugged ceramic surface without revealing the surface of the CNFs inside the ceramic layer.
Effect of the Electroless Nickel, Electroless Palladium, and Immersion Gold Multilayer as a Diffusion Barrier on the Bonding Strength of BiTe-Based Thermoelectric Modules
Authors: Nguyen Yen Ngoc , Dang Khanh Quoc , Son Injoon
Published: March 2021

An effective diffusion barrier layer was coated onto the surface of BiTe-based materials to avoid the formation of brittle intermetallic compounds (IMCs) by the diffusion of the constituents of Sn-based solder alloys into the BiTe-based alloys. In this study, the electrochemical deposition
of multi-layers, i.e., electroless nickel/electroless palladium/immersion gold (ENEPIG) was explored to enhance the bonding strength of BiTe materials with Cu electrodes. The thermoelectric modules with the ENEPIG plating layer exhibited high bonding strengths of 8.96 MPa and 7.28 MPa for
the n- and p-type, respectively that increased slightly to 9.26 MPa and 7.76 MPa, respectively after the thermoelectric modules were heated at 200 °C for 200 h. These bonding strengths were significantly higher than that of the thermoelectric modules without a plating layer.
Effect of Plating Layers on the Bonding Strength of p-Type Bi–Te Thermoelectric Elements
Authors: Yun Seong Min , Son Injoon , Bae Sung Hwa
Published: March 2021

In thermoelectric modules, multiple n-type and p-type thermoelectric elements are electrically connected in series on a Cu electrode that is bonded to a ceramic substrate. Defects in the bond between the thermoelectric elements and the Cu electrode could impact the performance
of the entire thermoelectric module. This study investigated the effect of plating layers on the bonding strength of p-type Bi–Te thermoelectric elements. Ni and Pd electroplating was applied to Bi–Te thermoelectric elements; further, electroless Ni–P immersion gold
(ENIG) plating was applied to Cu electrodes bonded to ceramic substrates. Forming a Pd/Ni electroplating layer on the surface of thermoelectric elements and an ENIG plating layer on the surface of the Cu electrode improved the bonding strength by approximately 3.5 times. When the Pd/Ni and
ENIG plating layers were formed on Bi–Te elements and Cu substrates, respectively, the solderability greatly increased; as the solderability increased, the thickness of the diffusion layer formed with the solder layer increased. The improved bonding strength of the Pd/Ni plated thermoelectric
element bonded on the ENIG plated substrate is attributed to the enhanced solderability due to the rapid inter-diffusion of Pd and Au into the solder layer and the formation of a stable and non-defected solder reaction interface layer.
Photocatalytic Decomposition of Organic Dyes Using a Rotating Cylinder System
Authors: Cho Young-Sang , Sung Sohyeon
Published: March 2021

In this study, a rotating cylinder system was used in the photocatalytic decomposition of organic dyes in aqueous medium for water purification. To this end, the titania nanoparticle dispersion was mixed with an organic dye solution under a rotating inner cylinder at controlled speed.
The rate constant was adjusted by changing the speed of rotation to determine the optimal circulating velocity. Since nanoparticle dispersion is a secondary contaminant after wastewater treatment, the titania paste was deposited on the inner surface of the stationary outer cylinder to form
a photocatalytic film. During repeated batch-mode operation, the deactivation of the deposited film was analyzed by measuring the rate constant as a function of time. Continuous operation was also used to remove organic dye in the water to study factors affecting the removal efficiency of
methylene blue. Higher rotating velocity and slow feed rate facilitated the removal of contaminants via desorption of adsorbed dyes with adequate retention time.
Synthesis of Macro-Porous De-NOx Catalysts for Poly-Tetra-Fluoro-Ethylene Membrane Bag Filter
Authors: Kwon Byung Chan , Kang Dohyung , Lee Seung Woo , Park No-Kuk , Lee Jang Hun , Hwang Sang Yeon , Seo Myoung Jo , Lim Dong-Ha
Published: March 2021

This study examined the effects of the porosity of catalytic bag-filter materials for applications to the SNCR (selective noncatalytic reduction)-SCR (selective catalytic reduction) hybrid process for highly treating nitrogen Oxides (NOx) in the exhaust gas of a combustion
process. A V2O5/TiO2 catalyst was dispersed in a PTFE (poly-tetra-fluoro-ethylene) used as the catalytic bag-filter material to remove particulate matter and nitrogen oxides contained in the combustion exhaust gas. Macroporous alumina was added into a V2O5/TiO2-dispersed
PTFE to improve the catalytic activity of V2O5/TiO2 dispersed in the PTFE material. In this study, the textural properties and denitrification performances of the V2O5/TiO2-dispersed PTFE materials were examined according to
the addition of macro-porous alumina. When the denitrification catalyst was solely dispersed in the PTFE material, the catalyst inside the PTFE backbone had low gas-solid contact efficiency owing to the low porosity of the PTFE materials, resulting in low denitrification efficiency. On the
other hand, the catalytic activity of V2O5/TiO2 dispersed inside the macro-porous PTFE material was significantly enhanced by adding macro-porous alumina into the PTFE matrix. The enhanced textural properties of the macro-porous PTFE material where V2O5/TiO2
was uniformly dispersed proved the facilitated diffusion of combustion exhaust gas into the PTFE material.
Effect of intra-articular injection of adipose stem cells on traumatic osteoarthritis cartilage defects
Authors: Wang Qian , Yang Na , Zhang Kun , Li Zhong , Zhu Yangjun , Song Zhe
Published: March 2021

Traumatic osteoarthritis with cartilage defects can lead to mobility problems. Mitotic activity in cartilage is extremely low, and once damaged, repairing can be difficult. The commonly used autologous or allogeneic cartilage transplantation techniques also have certain limitations.
In recent years, directed induction of osteoblastic differentiation using adipocytes has been shown to be effective in repairing cartilage defects. However, it is often induced in vitro and is prone to incomplete or over-differentiation. In addition, because of the large differences
in the in vivo and in vitro microenvironment, exploring the influence of these differences in the in vivo microenvironment on the directional differentiation of adipose-derived stem cells (ADSCs) and their effect on cartilage repair is necessary. In this study, a cartilage
defect model in rabbits with traumatic osteoarthritis of the left knee was established, and different interventions were conducted in different groups. We determined the effect of directly injecting ADSCs into the joints on repairing cartilage defects in rabbits with traumatic osteoarthritis
and analyzed the differences in repair time of newly developed cartilage defects and old cartilage frontal defects. The results indicated that the placement of a stent and injection of ADSCs improved the knee joint activity, increased the expression of BMP and TGF-β protein, and
reduced the expression of inflammatory factors, including IL-1β, IL-6, IL-17, and TNF-α. No difference was found between the new cartilage defect and the old one. By directly observing the cartilage defect, intervention with ADSCs + scaffold increased the connection
between the cartilage defect and the normal tissue and improved the cartilage repair effect. These results indicated that directly injecting ADSCs into the joints is an effective approach for repairing cartilage defects in traumatic osteoarthritis, and it was not affected by the age of the
defect.
Effects of ergosterone on lipopolysaccharideinduced acute lung injury and nucleo side-binding oligomerization domain, leucine-rich repeats and pyrin domain containing protein 3 inflammatory signaling pathway in mice
Authors: Zhang Yue , Zhao Tianyi , Wang Huan , Wang Jia , Wang Renguang , Bu Hongshi , Hu Liming , Hu De , Wang Shumin
Published: March 2021

Ergosterone has been found to have a diversity of pharmacological effects, but the effect on lipopolysaccharide (LPS) induced Acute Lung Injury (ALI) is not very clear. This study is aimed at assessing the action of ergosterone on LPS-induced ALI. Mice on the 7th day of ergosterone
prophylactic treatment were intranasally administered with an appropriate amount of LPS one hour before administration. After 12 hours, W/D ratio, TNF-α, IL-6, IL-1β, P-selectin, ICAM-1, NO, SOD and MDA levels were tested by ELISA in the obtained tissues. Besides,
western blot was used to detect NLRP3, ASC, pro-caspase-1, caspase-1, pro-IL-1β and IL-1β leves. The results indicated that ergosterone pretreatment apparently brought down W/D ratio, TNF-α, IL-6, IL-1β, NO and MDA in lung tissues, and significantly
increased SOD levels. Furthermore, ergosterone significantly inhibited the activation of NLRP3 induced by LPS. The results indicated that ergosterone has a significant protective action on ALI induced by LPS, and may inhibit the activation of the NLRP3 signaling pathway.
Osteocyte-derived exosomes inhibit osteoblast activity and induce osteoclast formation
Authors: Sun Xiaodi , Wang Yanying , Gu Ke , Wang Qingfu , Yang Jing , Mao Yupu , Deng Huanze , Zhang Jian
Published: March 2021

Osteocytes, which are the most abundant cell type in bone, regulate osteoblasts and osteoclasts via both cell–cell interactions and paracrine signaling, and osteocyte-derived exosomes might contribute to this paracrine action. In this study, we investigated the effects of osteocyte-derived
exosomes on regulating osteoblasts and osteoclasts and studied the potential mechanism. Materials and Methods: Osteocyte-derived exosomes were extracted and identified. PKH67-labeled exosomes were incubated with MC3T3-E1 cells and RAW264.7 cells, and fluorescence confocal microscopy
was used to analyze the uptake of exosomes. ALP stain- ing and TRAP staining were used to analyze osteoblast activity and osteoclast formation. The level of miR-214-3p in exosomes was analyzed by qPCR and the incorporation of FAM-labeled miR-214-3p from exosomes into MC3T3-E1 cells was evaluated.
The expressions of ephrinA2 and RANKL in exosomes were studied. Results: Our results demonstrated that osteocyte-derived exosomes might recognize osteoblasts through the ephrinA2 protein; thus, miR-214-3p in exosomes was transferred into osteoblasts to inhibit osteoblast activity. Meanwhile,
we found that osteocyte-derived exosomes could be transferred into osteoclasts to induce osteoclast formation by releasing RANKL. Conclusion: These findings suggest that osteocyte-derived exosomes play an important role in the regulation of osteoblast and osteoclast activity, which
might occur via miR-214-3p and RANKL.
Preparation and characterization of polyurethane-Rheum rhabarbarum-zirconium phosphate composite fiber with antibacterial and antioxidant properties
Authors: Luo Hao , Gong Dakai , Yang Feng , Zeng Rui , Zhang Yong , Tan Lin
Published: March 2021

Antibacterial and antioxidant fibers that prevent bacterial infection and oxidative damage have attracted great scientific interest in the textile industry and biomedical fields. The present study reports a novel composite fiber (TPU/ZrP/Rr) prepared by incorporating zirconium phosphate
(ZrP) with antibacterial property and natural Rheum rhabarbarum (Rr) powder possessing antioxidant activity into thermoplastic polyurethane (TPU) matrix via wet-spinning technology. The prepared fibers were systematically characterized for their structure, morphologies, mechanical properties,
surface wettability, antioxidant activity and antibacterial performance. The antioxidant activity of TPU/ZrP/Rr was evaluated according to the scavenging rates on three types of radicals of DPPH (2,2-diphenyl-1-picrylhydrazyl), superoxide anion and hydroxyl, and determined as 95.4%, 18.6%
and 20.7%, respectively; In addition, TPU/ZrP/Rr fibers exhibited high biocidal efficacy up to 99.99% according to the growth inhibition of Gram positive S. aureus and Gram negative E. coli through contact model. Collectively, the desirable antibacterial and antioxidant performance
as well as other properties enable the TPU/ZrP/Rr fibers to be very promising for biomedical textiles and food packaging applications.
Preparation of oxidized corn starch in dry method assisted by kneader
Authors: Li Ying , Zhang Kang , Song Ya-Lu , Cheng Fei , Zhou Mi , Lin Yi , Zhu Pu-Xin
Published: March 2021

In this study, oxidized starch (OCS) with different carboxyl content was prepared by the dry method, with H2O2 as the oxidant and CuCl2 as the catalyst. The optimum conditions were obtained by an orthogonal experiment, under the carboxyl and carbonyl
content of 0.6813 and 1.0416% respectively. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction and gel permeation chromatography characterized the structures of OCS, and the thermal, gelatinization, viscosity property and its viscosity stability were measured. The results demonstrated
that the crystallinity decreased slightly and the A-type crystal remained unchanged after oxidation, and the molecular weight of OCS decreased greatly. The thermal decomposition temperature, apparent viscosity and setback viscosity also decreased. With the increase of carboxyl content in OCS,
the cold-water solubility and paste transparency of OCS paste increased gradually, while the viscosity of OCS paste decreased, and the viscosity stability displayed a trend of first increasing and then reducing. The OCS obtained by a kneader had low solution viscosity and high viscosity stability,
suitable for sizing high count warp yarns.
Is it discriminatory to require hospital staff to be clean shaven to facilitate the effective wearing of personal protective equipment?
Authors: Steadman Amanda
Published: March 2021

National Health Service employers are subject to legal duties to protect the health and safety of their employees and third parties who come into contact with their staff. In order to discharge these duties, National Health Service employers must implement a range of protective measures to mitigate risk. One such measure is to require staff to wear personal protective equipment, including respiratory protective equipment, in certain circumstances. This is of particular importance during the Covid-19 pandemic. However, the presence of facial hair has a negative impact on the effectiveness of respiratory protective equipment. This article discusses whether a requirement to be clean shaven could amount to discrimination under the Equality Act 2010.
Internet regression and the meaning of self
Authors: Sharma Manoj Kumar , Anand Nitin , Srivastava Kalpana , Sunil Shweta
Published: March 2021

The internet provides a platform for expression of a new self that a user finds it difficult to achieve in the real world. This quality mediates disinhibited or regressive expression of self. The online disinhibited expression is also found to have to a direct correlation with a person’s self-concept, including their self-worth and self-control, which also contributes to lowering their social control through the social inadequacies they perceive themselves to have. The low self-control is being associated with engagement in bullying or cybercrime through online modalities. The report implicates for evolving intervention to manage cybercrimes from a psychological and legal perspective.
Mapping transnational commercial surrogacy arrangements in South and Southeast Asia
Authors: Attawet Jutharat
Published: March 2021

Transnational commercial surrogacy is a form of medical tourism undertaken by intended parents in an attempt to seek surrogates in other countries. Most intended parents are from developed countries and seek their surrogates from developing countries, predominantly from South and Southeast Asia. This arrangement led to the establishment of surrogacy businesses in South and Southeast Asia, in countries such as India and Thailand. Subsequently, the business was banned in these countries, which led to a trend of moving it to neighbouring countries where there were no regulations or restrictions. This paper maps the movement of the industry and calls for attention to re-consider or re-frame commercial surrogacy in an international framework.