Implications for Activating 3D printer Use for Education in Elementary and Secondary Schools

This research aims at analysing the usage of 3D Printing in education for school grades and suggest a way to encourage schools to use 3D Printers in Education. For this, a survey was done for 3,247 teachers in Gyeonggi Province on September. Usually schools are trying to buy 3D Printers to use it with software education courses. However with this survey, it turns out that teachers use 3D Printer with after school activities, creativity and experiential activities more than a regular courses. This is because there are not many teaching and learning materials for 3D Printers to be used with regular courses and it is hard for teachers to use 3D printers with professionality due to the fact that lack of the training. Therefore, to activate 3D printers in schools, not only budget support but also trainings for teachers and developing teaching and learning materials should be involved

Improvement of Diagnosis-Supplement System for Basic Academic Skill based on Affordance Theory in the Context of HCI

The purpose of this study is to apprehend a problem of user affordance and to suggest an improvement plan to make the better usability of Diagnosis-Supplement System for basic academic skill. Starting in 2013, from 5 cities and provinces, this system was developed, and in 2015, it was completed construction in all (17) provinces. Now, this system serves diagnosis test and supplement study materials for underachievement students from 3rd grade to 8th grade. As of 2015, the role of this system is gradually increased that 16 million students, about 4% of pupils throughout the country are now using it. In turn, this study tries to analyze various ranging requirements of teachers and experts by doing focus group interview in terms of user affordance and try to suggest the way to improve this system for the sustainable use. Henceforth the results of this study, which includes specific problems of physical, cognitive, sensual affordance and a design prototype to improve these problems, can be an important base material for the process of improving Diagnosis Supplement System for Basic Academic Skill with the effective and intuitive syste

Synthesis of Molybdenum Sulfide/Tellurium Hetero-Composite by a Simple One-Pot Hydrothermal Technique for High-Performance Supercapacitor Electrode Material

It is necessary to investigate effective energy storage devices that can fulfill the requirements of short-term and long-term durable energy outputs. Here, we report a simple one-pot hydrothermal technique through which to fabricate the MoS2/Te nanocomposite to be used as an effective electrode material for high-performance supercapacitors. Comprehensive characterization of the as-fabricated nanomaterial was performed using FESEM, HRTEM, XRD, FTIR, XPS, etc., as well as electrochemical characterizations. The electrochemical characterization of the as-fabricated nanocomposite electrode material showed a high specific capacitance of 402.53 F g−1 from a galvanostatic charge-discharge (GCD) profile conducted at 1 A g−1 current density. The electrode material also showed significant rate performance with high cyclic stability reaching up to 92.30% under 4000 cycles of galvanostatic charge-discharge profile at a current density of 10 A g−1. The highly encouraging results obtained using this simple synthetic approach demonstrate that the hetero-structured nanocomposite of MoS2/Te electrode material could serve as a promising composite to use in effective supercapacitors or energy storage devices

Controlled Thin Polydimethylsiloxane Membrane with Small and Large Micropores for Enhanced Attachment and Detachment of the Cell Sheet

Polydimethylsiloxane (PDMS) membranes can allow the precise control of well-defined micropore generation. A PDMS solution was mixed with a Rushton impeller to generate a large number of microbubbles. The mixed solution was spin-coated on silicon wafer to control the membrane thickness. The microbubbles caused the generation of a large number of small and large micropores in the PDMS membranes with decreased membrane thickness. The morphology of the thinner porous PDMS membrane induced higher values of roughness, Young’s modulus, contact angle, and air permeability. At day 7, the viability of cells on the porous PDMS membranes fabricated at the spin-coating speed of 5000 rpm was the highest (more than 98%) due to their internal networking structure and surface properties. These characteristics closely correlated with the increased formation of actin stress fibers and migration of keratinocyte cells, resulting in enhanced physical connection of actin stress fibers of neighboring cells throughout the discontinuous adherent junctions. The intact detachment of a cell sheet attached to a porous PDMS membrane was demonstrated. Therefore, PDMS has a great potential for enhancing the formation of cell sheets in regenerative medicine

Refined fabrication of mechano-stimulating micro-platform for on-chip analyses of complex platelet behavior

Platelets can sense their surroundings as they crawl in search of optimal surface to adhere before activation, but the detailed mechanism has not been fully explored in different microenvironments. Herein, various aspects of platelet behavior, including morphology, movement and biomarker expression, were multilaterally examined on mechanically stimulating surfaces, with controlled rigidity and roughness, to elucidate the effect of microenvironment without chemical stimulus. The platelets demonstrated different movement behavior (e.g. back-and-forth and forward crawling), and motility, as well as varying degrees of spreading with lamellipodial and filopodial projections, based on varying mechanical microenvironments. Furthermore, after initial activation, the platelets all became stationary and the cell spreading became more prominent, while still maintaining their movement potential. P-selectin expression, along with alpha-granule and open canalicular system (OCS) distributions, all supported the morphological and movement behavior. These results strongly indicated that the mechanical microenvironment played a key role in the regulation of complex platelet activities. (C) 2020 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved

Femtosecond Laser-Inscripted Direct Ultrafast Fabrication of a DNA Distributor Using Microfluidics

A femtosecond laser can be used for single or multiple writing processes to create sub 10-μm lines or holes directly without the use of masks. In this study, we characterized the depth and width of micro-channels created by femtosecond laser micro-scribing in polydimethylsiloxane (PDMS) under various energy doses (1%, 5%, 10%, 15% and 20%) and laser beam passes (5, 10 and 15). Based on a microfluidic simulation in a bio-application, a DNA distributor was designed and fabricated based on an energy dose of 5% and a laser beam pass of 5. The simulated depth and width of the micro-channels was 3.58 and 5.27 μm, respectively. The depth and width of the micro-channels were linearly proportional to the energy dose and the number of laser beam passes. In a DNA distribution experiment, a brighter fluorescent intensity for YOYO-1 Iodide with DNA was observed in the middle channels with longer DNA. In addition, the velocity was the lowest as estimated in the computational simulation. The polymer processability of the femtosecond laser and the bio-applicability of the DNA distributor were successfully confirmed. Therefore, a promising technique for the maskless fabrication of sub 10-μm bio-microfluidic channels was demonstrated

Comprehensive tuning of bioadhesive properties of polydimethylsiloxane (PDMS) membranes with controlled porosity

Polydimethylsiloxane (PDMS)-based elastomers have become the de facto platform for various biomedical applications. But the stable attachment of biomolecules to PDMS for more robust and longterm performance of the PDMS-based devices has been a significant challenge, owing to its unique physical properties (e.g. hydrophobicity, dynamic molecular mobility). Herein, the PDMS membrane with tunable surface porosity is developed via high-pressure saturated steam technology in order to promote a strong and lasting bioadhesion to the PDMS membrane without additional processing steps. The resulting porous PDMS membranes demonstrate enhanced physical properties (e.g. Young???s modulus, roughness, and air permeability), which is dependent on the membrane thickness. The bioactivity of porous PDMS membranes, evaluated by measuring the adhesion of various biomolecules and bioactivity of cells, shows significant improvement over conventional non-porous control. This effect can be attributed to the strong physical adsorption on the porous PDMS membrane by increased surface roughness and stiffness. In sum, the porous PDMS membrane provides a simple and yet highly effective platform to create bioactive surface for various biomedical devices

Facile Synthesis of alpha-Boryl-Substituted Allylboronate Esters Using Stable Bis[(pinacolato)boryl]methylzinc Reagents

Reported herein is the utilization of bis[(pinacolato)boryl]methylzinc halides, whose structures are characterized via single-crystal X-ray analysis, as solid storable reagents for copper-catalyzed coupling with vinyliodonum salts. The reaction proceeds under mild conditions and shows broad scope with respect to vinyliodonium salts, affording various alpha-boryl-substituted allylboronate esters in good yields. Synthetic applications of the obtained products are also demonstrated.11Nsciescopu