Mechanical Properties of Surface-Charged Poly(Methyl Methacrylate) as Denture Resins

The aim of this study was to examine the mechanical properties of a new surface-modified denture resin for its suitability as denture base material. This experimental resin is made by copolymerization of methacrylic acid (MA) to poly(methyl methacrylate) (PMMA) to produce a negative charge. Four experimental groups consisted of Orthodontic Dental Resin (DENTSPLY Caulk) as a control and three groups of modified PMMA (mPMMA) produced at differing ratios of methacrylic acid (5 : 95, 10 : 90, and 20 : 80 MA : MMA). A 3-point flexural test using the Instron Universal Testing Machine (Instron Corp.) measured force-deflection curves and a complete stress versus strain history to calculate the transverse strength, transverse deflection, flexural strength, and modulus of elasticity. Analysis of Variance and Scheffe Post-test were performed on the data. Resins with increased methacrylic acid content exhibited lower strength values for the measured physical properties. The most significant decrease occurred as the methacrylic acid content was increased to 20% mPMMA. No significant differences at P < .05 were found in all parameters tested between the Control and 5% mPMMA

Usability of the Stylus Pen in Mobile Electronic Documentation

Stylus pens are often used with mobile information devices. However, few studies have examined the stylus’ simple movements because the technical expertise to support documentation with stylus pens has not been developed. This study examined the usability of stylus pens in authentic documentation tasks, including three main tasks (sentence, table, and paragraph making) with two types of styluses (touchsmart stylus and mobile stylus) and a traditional pen. The statistical results showed that participants preferred the traditional pen in all criteria. Because of inconvenient hand movements, the mobile stylus was the least preferred on every task. Mobility does not provide any advantage in using the stylus. In addition, the study also found inconvenient hand support using a stylus and different feedback between a stylus and a traditional pen.This study was supported by the Dongguk University Research Fund of 2015. Support for the University Jaume-I (UJI) Robotic Intelligence Laboratory is provided in part by Ministerio de Economía y Competitividad (DPI2011-27846), by Generalitat Valenciana (PROMETEOII/2014/028) and by Universitat Jaume I (P1-1B2014-52)

Can Large Educational Institutes Become Free from Grid Systems? Determination of Hybrid Renewable Energy Systems in Thailand

In some countries, renewable energy resources have become one of the mainstreams of energy savings and sustainable development. Thailand is one of the major countries to use renewable energy generation facilities in public buildings. In particular, public educational institutes consume large amounts of electricity from the grid. To reduce the electricity dependency on the national grid connection and greenhouse gas emissions, this paper introduces potential optimized solutions of renewable energy generation systems for a public university in Thailand, Chiang Mai University. Based on the simulation results from HOMER software, the potential configuration organized by PV panels, batteries and converters is proposed. The suggested configuration achieves 100% of the renewable fraction with $0.728 of the cost of energy for per electricity. Moreover, the greenhouse gas emissions are significantly reduced. Both the implications and limitations are presented based on simulation results

Exceptional rigidity and biomechanics of amyloid revealed by 4D electron microscopy

Amyloid is an important class of proteinaceous material because of its close association with protein misfolding disorders such as Alzheimer’s disease and type II diabetes. Although the degree of stiffness of amyloid is critical to the understanding of its pathological and biological functions, current estimates of the rigidity of these β-sheet–rich protein aggregates range from soft (10^8 Pa) to hard (10^(10) Pa) depending on the method used. Here, we use time-resolved 4D EM to directly and noninvasively measure the oscillatory dynamics of freestanding, self-supporting amyloid beams and their rigidity. The dynamics of a single structure, not an ensemble, were visualized in space and time by imaging in the microscope an amyloid–dye cocrystal that, upon excitation, converts light into mechanical work. From the oscillatory motion, together with tomographic reconstructions of three studied amyloid beams, we determined the Young modulus of these highly ordered, hydrogen-bonded β-sheet structures. We find that amyloid materials are very stiff (10^9 Pa). The potential biological relevance of the deposition of such a highly rigid biomaterial in vivo are discussed

Determinants of Behavioral Intention to Use South Korean Airline Services: Effects of Service Quality and Corporate Social Responsibility

Since the introduction of corporate social responsibility (CSR), it has become an important duty of companies and organizations. In addition, academic and industry researchers have attempted to explore the effects of corporate social responsibility on firm performance. To this end, this study examined how corporate social responsibility and service quality are notably associated with customer satisfaction and behavioral intention to use by employing a structural equation modeling method. A research model with nine constructs was introduced and the findings revealed that economic, social, and environmental responsibility, as well as in-flight service quality, significantly determined customer satisfaction, while there were notable connections between customer satisfaction and behavioral intention to use. However, service quality at airports did not have a significant effect on satisfaction. The practical and theoretical implications of the current study are discussed

Task complexity interacts with state-space uncertainty in the arbitration between model-based and model-free learning

It has previously been shown that the relative reliability of model-based and model-free reinforcement-learning (RL) systems plays a role in the allocation of behavioral control between them. However, the role of task complexity in the arbitration between these two strategies remains largely unknown. Here, using a combination of novel task design, computational modelling, and model-based fMRI analysis, we examined the role of task complexity alongside state-space uncertainty in the arbitration process. Participants tended to increase model-based RL control in response to increasing task complexity. However, they resorted to model-free RL when both uncertainty and task complexity were high, suggesting that these two variables interact during the arbitration process. Computational fMRI revealed that task complexity interacts with neural representations of the reliability of the two systems in the inferior prefrontal cortex

Antecedents of Behavioral Intention to Use Mobile Telecommunication Services: Effects of Corporate Social Responsibility and Technology Acceptance

The concepts of corporate social responsibility (CSR) and user experience have been identified as core determinants of the success of service providers. Accordingly, practitioners and researchers have investigated the effects of service providers’ CSR and user experience on behavioral intention to use a particular service. Based on the importance of these concepts, the current study integrates subjective dimensions of CSR with the technology acceptance model (TAM) to explore whether the CSR efforts of mobile telecommunication services providers and the service acceptance of their customers have significant effects on behavioral intention to use a service. We apply structural equation modeling and find that two factors from the TAM (i.e., usefulness and ease of use) as well as economic, social, and environmental responsibility are significantly related to customer attitude and satisfaction. Moreover, our results show that there are significantly positive relationships between customer attitude and behavioral intention to use a service, as well as between customer satisfaction and intention. Practical and theoretical implications along with notable limitations of the current study are presented

Pressure-induced polarization reversal in multiferroic YMn2O5YMn_2O_5

The low-temperature ferroelectric polarization of multiferroic $YMn_2O_5$ is completely reversed at a critical pressure of 10 kbar and the phase transition from the incommensurate to the commensurate magnetic phase is induced by pressures above 14 kbar. The high-pressure data correlate with thermal expansion measurements indicating a significant lattice strain at the low-temperature transition into the incommensurate phase. The results support the exchange striction model for the ferroelectricity in multiferroic $RMn_2O_5$ compounds and they show the importance of magnetic frustration as well as the spin-lattice coupling

Economic and environmental benefits of optimized hybrid renewable energy generation systems at Jeju National University, South Korea

In order to minimize the social and environmental concerns arising from the use of traditional energy resources such as fossil fuels and nuclear energy, the South Korean government has attempted to develop alternative energy resources. In particular, the large educational institutes and islands in South Korea—which have the motivation and potential to provide electrical services—are required to install renewable electricity generation facilities to reduce the burden on the local grid systems. With this trend, the current study investigates potential configurations of renewable electricity generation systems to supply the electrical demand of Jeju National University, located on the largest island in South Korea. The potential configurations suggested by the simulation results are evaluated by renewable fraction, cost of energy (COE), and total net present cost (NPC). The suggested configurations show a renewable fraction of 1.00 with COE of $0.356–$0.402 per kWh and NPC of $54,620,352–$51,795,040. Based on the results, both implications and limitations are examined.This study was supported by the Dongguk University Research Fund of 2015. Support for the UJI Robotic Intelligence Laboratory is provided in part by Ministerio de Economía y Competitividad (DPI2015-69041-R), by Generalitat Valenciana (PROMETEOII/2014/028) and by Universitat Jaume I (P1-1B2014-52)

Heat transport study of the spin liquid candidate 1T-TaS2

We present the ultra-low-temperature thermal conductivity measurements on single crystals of the prototypical charge-density-wave material 1$T$-TaS$_2$, which was recently argued to be a candidate for quantum spin liquid. Our experiments show that the residual linear term of thermal conductivity at zero field is essentially zero, within the experimental accuracy. Furthermore, the thermal conductivity is found to be insensitive to the magnetic field up to 9 T. These results clearly demonstrate the absence of itinerant magnetic excitations with fermionic statistics in bulk 1$T$-TaS$_2$ and, thus, put a strong constraint on the theories of the ground state of this material.Comment: 5 pages, 3 figure