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Electroencephalography (EEG) captures minute electrical signals emanating from the brain. These signals are vulnerable to interference from external noise and dynamic artifacts; hence, accurately recording such signals is challenging. Although dry electrodes are convenient, their signals are of limited quality; consequently, wet electrodes are predominantly used in EEG. Therefore, developing dry electrodes for accurately and stably recording EEG signals is crucial. In this study, we developed flexible dry electrodes using polydimethylsiloxane (PDMS)/carbon-nanotube (CNT) composites with isotropically wrinkled surfaces that effectively combine the advantages of wet and dry electrodes. Adjusting the PDMS crosslinker ratio led to good adhesion, resulting in a highly adhesive CNT/PDMS composite with a low Young’s modulus that exhibited excellent electrical and mechanical properties owing to its ability to conformally contact skin. The isotropically wrinkled surface also effectively controls dynamic artifacts during EEG signal detection and ensures accurate signal analysis. The results of this study demonstrate that dry electrodes based on flexible CNT/PDMS composites and corrugated structures can outperform wet electrodes. The introduction of such electrodes is expected to enable the accurate analysis and monitoring of EEG signals in various scenarios, including clinical trials.

As the three largest central hub cities in the Pearl River Delta (PRD) region, Hong Kong, Guangzhou, and Shenzhen have played critical roles in regional growth. Nevertheless, these ports face many challenges, such as port handling capacity, environmental problems, and the expansion of the complex transportation system owing to the large volume of goods. Therefore, this study used the slacks-based measure–data envelopment analysis (SBM-DEA) and DEA-undesirable models to evaluate the efficiency of the major container terminals in these three cities between 2018 and 2019. Based on the decision-making unit values of the terminals for the past two years, Yantian and Container Terminal 9 (South) were the most efficient, followed by container terminals 6 and 7. Moreover, the efficiency of the major container terminals in Guangzhou was less satisfactory than that of terminals in Shenzhen and Hong Kong. The results provide a reliable reference for future port investment, and regional development policy in the PRD region.

Background/Aims The preventive role of hydroxychloroquine (HCQ) on coronavirus disease 2019 (COVID-19) remains unclear. The aim of this study was to examine the effects of HCQ and other immunosuppressive drugs on the incidence of COVID-19. Methods The data were collected from the South Korea National Health Insurance Sharing-COVID-19 database. All individuals who underwent nasopharyngeal and oropharyngeal swab tests for COVID-19 from January 2020 to May 2020 are included. The association between COVID-19 risk and HCQ use was examined in a propensity score-matched population. Factors associated with COVID-19 were identified using multiple logistic regression analysis. Results Total 8,070 patients with COVID-19 and 121,050 negative controls were included from the database. Among all participants, 381 were HCQ users. In a propensity score-matched population, the incidence of COVID-19 was 7.1% in HCQ users and 6.8% in non-users. The odds ratio (OR) for HCQ use was 1.05 with a 95% confidence interval (CI) of 0.58 to 1.89. Among the subpopulation of patients with rheumatoid arthritis (RA), 33 were diagnosed with COVID-19 and 478 were not. Use of HCQ, glucocorticoids, or other immunosuppressive drugs was not associated with COVID-19 risk, whereas abatacept use was. Chronic lung disease was an independent risk factor for COVID-19 diagnosis in patients with RA (adjusted OR, 6.07; 95% CI, 1.10 to 33.59). Conclusions The risk of COVID-19 did not differ between HCQ users and non-users. Glucocorticoids, conventional disease-modifying antirheumatic drugs (DMARDs), and biological DMARDs other than abatacept did not increase the risk of COVID-19.

Although Sn has been intensively studied as one of the most promising anode materials to replace commercialized graphite, its cycling and rate performances are still unsatisfactory owing to the insufficient control of its large volume change during cycling and poor electrochemical kinetics. Herein, we propose a Sn-TiO2-C ternary composite as a promising anode material to overcome these limitations. The hybrid TiO2-C matrix synthesized via two-step high-energy ball milling effectively regulated the irreversible lithiation/delithiation of the active Sn electrode and facilitated Li-ion diffusion. At the appropriate C concentration, Sn-TiO2-C exhibited significantly enhanced cycling performance and rate capability compared with its counterparts (Sn-TiO2 and Sn-C). Sn-TiO2-C delivers good reversible specific capacities (669 mAh g−1 after 100 cycles at 200 mA g−1 and 651 mAh g−1 after 500 cycles at 500 mA g−1) and rate performance (446 mAh g−1 at 3000 mA g−1). The superiority of Sn-TiO2-C over Sn-TiO2 and Sn-C was corroborated with electrochemical impedance spectroscopy, which revealed faster Li-ion diffusion kinetics in the presence of the hybrid TiO2-C matrix than in the presence of TiO2 or C alone. Therefore, Sn-TiO2-C is a potential anode for next-generation Li-ion batteries.

Polymers mixed with conductive fillers hold significant potential for use in stretchable and wearable sensor devices. Enhancing the piezoresistive effect and mechanical stability is critical for these devices. To explore the changes in the electrical resistance under high strains, typically unachievable in single-layer composites, bi-layer structures were fabricated from carbon nanotubes (CNTs) and EcoFlex composites to see unobservable strain regions. Spherical types of non-conductive fillers composed of polystyrene and conductive filler, coated with Ni and Au on non-conductive fillers, were used as secondary fillers to improve the piezoresistive sensitivity of composites, and their respective impact on the conductive network was compared. The electrical and mechanical properties were examined in the static state to understand the impact of these secondary fillers. The changes in the electrical resistance under 100% and 300% tensile strain, and their dependence on the inherent electrical properties of the secondary fillers, were also investigated. Single-layer CNT composites proved incapable of withstanding 300% strain, whereas the bi-layer structures proved resilient. By implementing cyclic stretching tests, contrary to non-conductive fillers, reduced piezoresistive influence of the conductive secondary filler under extreme strain conditions could be observed.

Southern Vietnam is a key economic region for the country, producing 45% of Vietnam’s GDP, despite only accounting for 9% of the country’s total landmass and 21% of its population. Specifically, the Southern Region dominates seaport-based container transportation, contributing 55% of Vietnam’s total vessel calls and 74% of its total container cargo volume, with the North and Central regions trailing far behind. However, despite the sector’s importance, the efficiency of container terminals in Southern Vietnam has not been evaluated by the literature in recent years. This study fills this research gap by using data envelopment analysis (DEA) to evaluate the efficiency of major container terminals in Southern Vietnam. The results of the DEA Malmquist analysis show that most container terminals demonstrated productivity growth between 2017 and 2019, and that this mainly derived from advancements in catch-up operational efficiency and in technological innovation. Moreover, the DEA slack-based measure and DEA undesirable output analyses demonstrate that three container terminals (Cai Mep International Terminal, Tan Cang Cat Lai, and Tan Cang–Cai Mep International Terminal) achieved the maximum efficiency level when both applying and not applying the undesirable output variable. However, other container terminals displayed severe operational inefficiency, with these terminals’ efficiency values decreasing by between 9% and 40% when considering undesirable outputs. The ineffective terminals can therefore be categorized as consuming excessive inputs and lacking in the production of desirable outputs or creating large amounts of undesirable outputs. Therefore, using these results, port authorities and policymakers should be better placed to develop appropriate strategies for managing container terminals in Southern Vietnam.

The Northern Sea Route (NSR) has gradually become viable because of sea ice melting in the Artic. There is a large and diverse body of research on the NSR, investigating aspects such as weather, the environment, legal security, infrastructure and technologies, shipping transportation, and economic issues. However, there has been scant research carried out from a macroscopic perspective on NSR research trends. The purpose of this study is to analyze the trends in research about the NSR by applying a social network analysis. By collecting keywords from academic papers on the NSR, a network of keywords and two indexes (degree centrality and betweenness centrality) are accessed and analyzed. The results show that the trends can be divided into three periods (1899–1999, 2000–2009, 2010–2019). Throughout all periods, the issue of climate change causing the ice in the Arctic to melt has been a consideration for many scholars. In addition, “national security” and “oil exploitation” were important keywords in the first period. In the second period (2000–2010), in addition to words related to the environment, such as “sea ice” and “climate change,” the term “ocean transport” appears and becomes a central topic of research. This is because when the NSR has a non-icy period, ocean transport through the NSR can be deployed. The research trends become obvious in the third period (2011–2019) with two primary research areas: climate change and shipping area, which accurately measure the benefit and cost. This paper shows the importance of the NSR, reviews the main research topics involving the NSR, and informs researchers and authorities as to the trends in academic research on the NSR.

Sourdough bread fermented with yeast and lactic acid bacteria (LAB) is thought to have various beneficial health effects. However, its beneficial effects were not fully evaluated with in vivo mouse model. To evaluate these effects in vivo, a mouse feeding study and microbiome analysis of white bread containing 40% sourdough (WBS) and yeast-leavened white bread (WB) were performed. Although feed consumption and body weight increased with WBS, the glycemic index was reduced, suggesting a diabetes-lowering effect, probably due to the presence of dietary fiber and short-chain fatty acids (SCFA). In addition, a mineral absorption test showed that WBS increased magnesium absorption owing to phytate degradation during fermentation. Interestingly, WBS decreased total cholesterol and triglycerides, probably due to the dietary fiber and SCFA in LAB. In addition, the ratio of low- and high-density lipoprotein was decreased in WBS, implying potential risk reduction for cardiovascular disease. An immunomodulatory assay of WBS revealed that pro-inflammatory cytokines TNF-α and IL-6 were decreased, suggesting anti-inflammatory activity. Gluten degradation by fermentation and antioxidation activity of menaquinol/ubiquinol by gut microbiota also supported the anti-inflammatory activity of sourdough bread. Furthermore, some beneficial gut bacteria, including Akkermansia, Bifidobacterium, and Lactobacillus, were increased in WBS. In particular, Akkermansia has been associated with anti-inflammatory properties. Consequently, WBS has beneficial effects on health, including decreased glycemic index and cholesterol, increased mineral availability and absorption, anti-inflammatory properties, and establishment of healthy gut microbiota.

As the penetration of distributed energy resources (DER) has increased, research on direct current (DC) power transmission and distribution has been actively performed. The DC system has the advantage of high-power transmission efficiency. However, it has a very large and rapid increase in fault current in the DC system directly after a fault occurs. As one of the countermeasures, studies on the application of the superconducting fault current limiter (SFCL) into the DC system have been conducted to protect major facilities from DC fault current, which is expected to alleviate the power burden on the DC circuit breaker through its quench operation. Among the studied DC SFCLs, the trigger-type DC SFCL using a transformer, which can achieve the peak DC fault current-limiting operation, has been suggested. However, the DC fault current-limiting operation, in the case of the DC SFCL with a current-limiting reactor (CLR), was analyzed to not be effectively executed in the steady state since the transient state directly follows the fault occurrence. In this paper, the DC fault current-limiting operation of a twice-quench trigger type SFCL using a transformer considering magnetizing current and its CLR was analyzed. Through DC fault current-limiting experiments according to the inductance of its current-limiting reactor (CLR), the effective current-limiting design of twice-quench trigger type SFCL using a transformer was described.

We investigate the impact of observability of contracts between a plaintiff and his attorney on both the efficiency of the environmental conflict and the fairness of the resulting outcome from the environmental conflict. By including two specific game-theoretic models (an observable-contract game and an unobservable-contract game), we find two key results: (i) The unobservability of a contract may increase inefficiency of the environmental conflict in terms of legal efforts; however, (ii) the unobservability of a contract may increase the fairness of the outcome in terms of the plaintiff’s probability of winning the contest.

Despite the dominance of the Caribbean as the leading cruise destination in the world, research that focuses on the network of cruise ports in the region is limited. To fill this research gap, the current study carried out social network analysis (SNA) to inquire into cruise port interconnections and their influence on the operation of the entire Caribbean port network. The results are summarized as follows: First, in terms of connections among ports linked to the Caribbean region, a European port and a Southampton harbor exhibit the most significant in-degree and out-degree centrality. Nevertheless, ports within the Caribbean region are still significantly represented as regards both indexes. Second, in the matter of port influence, Caribbean ports are considerably the most important with respect to hub and authority centrality (HAC), especially those located in Florida and the eastern Caribbean. This research contributes to industry through its presentation of an extended panorama of the cruise network in the region, subjecting several ports to respective analyses that describe their principal characteristics and attractiveness in the industry.

Objectives: Osteoporosis and fracture are known complications of systemic lupus erythematosus (SLE). We assessed the prevalence and risk factors for osteoporosis in patients with SLE. Methods: A total of 155 female SLE patients were recruited retrospectively in 5 university hospitals. The bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry, and the fracture risk assessment tool (FRAX) for high-risk osteoporotic fractures was calculated with and without BMD. Results: The mean age was 53.7 ± 6.8 years, and osteoporotic fractures were detected in 19/127 (15.0%) patients. The proportion of patients having a high-risk for osteoporotic fractures in the FRAX with and without BMD, and osteoporosis by the World Health Organization (WHO) criteria were 25 (16.1%), 24 (15.5%), and 51 (32.9%), respectively, and 48.0–68.6% of them were receiving treatment. On multivariate logistic analysis, nephritis (odds ratio [OR] 11.35) and cumulative dose of glucocorticoid (OR 1.1) were associated with high-risk by the FRAX with BMD, and low complement levels (OR 4.38), erythrocyte sedimentation rate (ESR) (OR 1.04), and cumulative dose of glucocorticoid (OR 1.05) were associated with osteoporosis by the WHO criteria in patients with SLE. Conclusions: Among Korean female patients with SLE, the proportion of patients having a high-risk of osteoporotic fractures by the FRAX tool was 15.5%–16.1% and the proportion of patients having osteoporosis by the WHO criteria was 32.9%. In SLE, nephritis, low level of complement, ESR, and cumulative dose of glucocorticoids may contribute to fracture risk.

Telemedicine, particularly telerehabilitation for patients with chronic conditions such as spinal cord injury (SCI), has greatly evolved in the 21st century and expanded rapidly during the COVID-19 pandemic. Rehabilitation programs aiming to improve motor functions after SCI are important in reducing disability, promoting independence, and alleviating burden of caretakers. An appropriate intervention is limited to many patients due to requirements of periodic access to a location with appropriate equipment as well as a therapist to facilitate a one-on-one session to improve upper limb functions. Therefore, telerehabilitation can increase access to appropriate interventions to improve upper limb functions. This paper shows the limitations and benefits as well as the potential future of telerehabilitation based on a summertime experience of a rising 2nd year medical student.

Compression and tension sensors with a porous structure have attracted attention recently. Porous sponge sensors have the advantage of a wide deformation range owing to their structural characteristics. In this study, a porous sponge structure was prepared by absorbing polydimethylsiloxane (PDMS) into the matrix of porous commercial sugar cubes. A conductive network was formed by coating the outside of the sponge skeleton with silver nanowires (AgNWs), which have a high aspect ratio. In addition, a liquid metal (LM), which does not directly form an electrical network but changes from zero-dimensional to one-dimensional under an external force was introduced into this porous sponge structure. The effects of the LM on the sensor sensitivity to pressure and strain were analyzed by comparing the electrical resistance changes of PDMS/AgNW and LM/PDMS/AgNW sponge sensors under tension and pressure. This study shows that the use of a porous structure and an LM may be useful for future wearable sensor design.

Conducting polymer composites consisting of carbon nanotubes (CNTs) as a conductive filler and polydimethylsiloxane (PDMS) as a polymer matrix were fabricated to investigate their capacitive and piezoresistive effects as pressure sensors. The pressure-sensing behavior and mechanism of the composites were compared in terms of basic configuration with a parallel plate structure. Various sensing experiments, such as sensitivity, repeatability, hysteresis, and temperature dependence according to the working principle, were conducted with varying filler contents. The hysteresis and repeatability of the pressure-sensing properties were investigated using cyclic tensile tests. In addition, a temperature test was performed at selected temperatures to monitor the change in the resistance/capacitance.

Background/Aims To define standard reference values for musculoskeletal ultrasonography (MSUS) in Korea. Methods A total of 251 healthy adults were recruited for this study. Ultrasonography was performed by experienced rheumatologists who had undergone four appropriate training programs in Korea. A General Electric LOGIQ electronic ultrasound device fitted with a 12 MHz linear transducer was employed. Mean values ± standard deviations (SDs) were defined as standard reference values. Intraclass correlation coefficients was employed to evaluate the extent of inter- and intraobserver agreement when MSUS measurements were made. Results The 251 study participants included 122 males. Mean subject age was 28.6 years. The average bone-to-capsule distance of the right-side second and third metacarpophalangeal (MCP) joints were 0.68 and 0.72 mm respectively, and those of the left-side joints 0.62 and 0.68 mm. The cartilage thicknesses of the right-side second and third MCP joints were 0.55 and 0.55 mm, and those of the left-side joints were 0.55 and 0.56 mm, respectively. The bone-to-capsule distances of the right and left wrists were 0.80 and 0.82 mm. In 12.4% of participants (31/251), the erosion score of the humeral head was 1.71. In the right-side knee joint, mean cartilage thicknesses of the medial and lateral condyles were 1.86 and 2.03 mm in longitudinal scans. High overall interobserver agreement was evident after appropriate training that included instruction on standard MSUS methodology. Conclusions We defined standard reference values for MSUS in healthy Korean adults. The reliabilities of interobserver agreements were high after appropriate training program.

Carbon nanotube–polymer composites containing secondary fillers are thought to possess enhanced electrical and mechanical properties. Here the authors combine Monte Carlo calculations with resistivity experiments to study the effect of filler size and shape on electrical conductivity.

Background/Aims Rheumatology in Korea has rapidly advanced in the 24 years since the subspecialty board certification program was established in 1992. The objective of this investigation was to analyze the distribution of rheumatology practices in Korea in order to better understand the rheumatology workforce. Methods Using a membership list from the Korean College of Rheumatology (KCR), we obtained information on practicing rheumatologists. We mapped the ratio of rheumatologists to the general population and to patients with rheumatologic disease using data from Statistics Korea and the 2015 Health Insurance Review & Assessment Service (HIRA). Results In the 16 administrative districts of Korea in 2015, there were 311 practicing rheumatologists on the list of KCR members. There were 218 members practicing in metropolitan areas and 93 members in the provinces. The mean number of rheumatologists per 100,000 people was 0.60, with 0.33/100,000 in the provinces, but 0.92/100,000 in metropolitan areas, a 2.7-fold difference. The number of rheumatologists per 100,000 patients with chronic rheumatic disease was 17.21 in metropolitan areas but 6.57 in the provinces, according to 2015 HIRA data. This geographic maldistribution emerged as a problem; indeed, the regional disparity in the distribution of Korean rheumatologists was striking when compared to the published medical professional distribution in 2014. Conclusions Because of the uneven distribution of rheumatologists, it is likely that some patients with chronic rheumatic conditions have limited access to rheumatology care. Thus, a policy-based approach is needed to alleviate this disparity.

In recent years, flexible and wearable strain sensors, consisting of a polymer matrix and a conducting filler, have received extensive attention owing to their physical advantages, such as being lightweight, stretchable, and having the potential for application to complex forms. However, achieving a low hysteresis of the relative change in resistance, wide sensing range, and reduced plastic deformation is still challenging. To address these issues, in this study, we developed hybrid conducting composites with a wide range of sensing abilities and low hysteresis. The bi-layer composites, comprising a carbon nanotube (CNT) composite layer with reinforced/conducting properties, and a natural rubber-based layer with extreme strain properties, could effectively circumvent their limitations. Compared to single-layer CNT composites, the bi-layer structure could increase the tensile strain with reduced plastic deformation, resulting in the prevention of surface cracks on the CNT composite. In addition, it has the benefit of measuring a wider sensing range, which cannot be measured in a single-CNT composite system. A cyclic stretching/releasing test was performed to demonstrate that the strain sensor exhibited excellent reproducibility. Our results can function as a useful design guide for stretchable sensor applications.

Through the installation of electron gun and photon detector, an in-situ photoemission and damage-free sputtering integrated analysis system is completely constructed. Therefore, this system enables to accurately characterize the energy level alignments including unoccupied/occupied molecular orbital (LUMO/HOMO) levels at interface region of organic semiconductor/electrode according to depth position. Based on Ultraviolet Photoemission Spectroscopy (UPS), Inverse Photoemission Spectroscopy (IPES), and reflective electron energy loss spectroscopy, the occupied/unoccupied state of in-situ deposited Tris[4-(carbazol-9-yl)phenyl]amine (TCTA) organic semiconductors on Au (ELUMO: 2.51 eV and EHOMO: 1.35 eV) and Ti (ELUMO: 2.19 eV and EHOMO: 1.69 eV) electrodes are investigated, and the variation of energy level alignments according to work function of electrode (Au: 4.81 eV and Ti: 4.19 eV) is clearly verified. Subsequently, under the same analysis condition, the unoccupied/occupied states at bulk region of TCTA/Au structures are characterized using different Ar gas cluster ion beam (Ar GCIB) and Ar ion sputtering processes, respectively. While the Ar ion sputtering process critically distorts both occupied and unoccupied states in UPS/IPES spectra, the Ar GCIB sputtering process does not give rise to damage on them. Therefore, we clearly con?rm that the in-situ photoemission spectroscopy in combination with Ar GCIB sputtering allows of investigating accurate energy level alignments at bulk/interface region as well as surface region of organic semiconductor/electrode structure. [ABSTRACT FROM AUTHOR]

A crack growth simulation program based on the advanced iterative-finite element method (AI-FEM) was developed to predict realistic crack growth of structures. The developed program was suggested to calculate the exact stress intensity factor for arbitrary structures by regenerating the crack tip mesh as the crack grows. The main advantages of the developed program are to estimate each different crack growths along the crack tip line and to simulate the cracking transition from a surface crack to a through-wall crack under a complex stress field. For these purposes, the sensitivity analyses were performed for various influence variables on stress intensity factors, such as element types and crack dimensions. Based on the results of sensitivity analyses, the appropriate criteria for crack tip modeling to be used in AI-FEM were suggested to calculate sufficient converged SIF. The program developed in this research was validated through stress corrosion crack growth and natural crack growth examples including cracking transition, and it was confirmed that the program simulates crack growth well and has reasonable methods for cracking transition.

Polymer composites containing conductive fillers that utilize the piezoresistive effect can be employed in flexible pressure sensors. Depending on the filler used, different characteristics of a pressure sensor such as repeatability, sensitivity, and hysteresis can be determined. To confirm the variation of the pressure sensing tendency in accordance with the dimensions of the filler, carbon black (CB) and carbon nanotubes (CNTs) were used as representative 0-dimension and 1-dimension conductive fillers, respectively. The piezoresistive effect was exploited to analyze the process of resistance change according to pressure using CB/PDMS (polydimethylsiloxane) and CNT/PDMS composites. The electrical characteristics observed for each filler were confirmed to be in accordance with its content. The pressure sensitivity of each composite was optimized, and the pressure-sensing mechanism that explains the difference in sensitivity is presented. Through repeated compression experiments, the hysteresis and repeatability of the pressure-sensing properties were examined.

In response to the rising need for flexible and lightweight materials capable of efficient heat transport, many studies have been conducted to improve the thermal properties of polymers via nanofillers. Among the various nanofillers, carbon nanotubes (CNTs) are considered as the most promising, owing to their excellent thermal and electrical properties. Accordingly, CNT/polymer composites can be used as flexible and lightweight heat transfer materials, owing to their low density. In this study, we fabricated multi-walled CNT (MWCNT)/polymer composites with different aspect ratios to investigate their effects on electrical and thermal properties. Through a three-roll milling process, CNTs were uniformly dispersed in the polymer matrix to form a conductive network. Enhanced electrical and thermal properties were observed in MWCNT composite with a high aspect ratio as compared to those with a low aspect ratio. The thermal conductivity of composites obtained as a function of the filler content was also compared with the results of a theoretical prediction model.

The key characteristics of bending sensors are piezoresistive effect, hysteresis, and durability. In this study, to investigate the influence of the aspect ratio and contents of multi-walled nanotubes (MWNTs) on the properties of bending sensors, MWNT/polydimethylsiloxane (PDMS) composites were fabricated with various aspect ratios and filler contents. The MWNTs were uniformly dispersed in the composites using the three-roll milling method. By increasing the bending angle gradually, the sensitivity of each composite was analyzed. Furthermore, discontinuous cyclic bending tests were conducted to investigate the piezoresistive effect and hysteresis. In addition, stable repeatability of the composites was confirmed through continuous cyclic bending tests. As a result, optimal aspect ratios and filler contents have been presented for application in bending sensors of MWNT composites.

Highly aligned multi-walled carbon nanotube (MWCNT) polymer composites were fabricated via a roll-to-roll milling process; the alignment of the MWCNTs could be controlled by varying the speed of the rotating rolls. The effect of MWCNT alignment on the polymer matrix was morphologically observed and quantitatively characterized using polarized Raman spectroscopy. To provide a more detailed comparison, MWCNT composites with alignment in the transverse direction and random alignment were fabricated and tested. Enhanced mechanical and electrical properties were obtained for the aligned MWCNT composite, which can be attributed to the efficient electrical network and load transfer, respectively. In addition, a cyclic stretching test was conducted to evaluate the piezo-resistive characteristics of the aligned MWCNT composites. The composites with an aligned filler configuration showed an exceptionally high degree of strain sensitivity compared to the other composites.

For filler composite systems used in strain sensor applications, piezoresistive effect, strain hysteresis, and repeatability are critical factors, which have to be clearly evaluated and understood. To investigate the effects of the aspect ratio and content of a multi-walled carbon nanotube (MWCNT) on the strain sensor properties of the composite, MWCNT/Polydimethylsiloxane (PDMS) composites with varying filler contents and aspect ratios were fabricated. In order to uniformly disperse MWCNTs on the polymer matrix, we used a three-roll milling method to generate high shear force for de-bundling MWCNTs. Mechanical and electrical properties of the MWCNT composites were evaluated for each case. In addition, through the cyclic stretching test, we optimized the strain-sensing properties of the MWCNT composites by considering their piezoresistive effects and strain hysteresis.

Amylose-lipid complex (ALC) was prepared with corn starch and stearic acid and used as a shortening replacement in white pan bread preparation. ALCs were prepared using various concentrations of stearic acid to corn starch (1%, 3%, 5%, and 7%) under different temperatures (55, 65, and 75 °C) and for different durations of time (30, 60, and 120 min); then, their complexing properties were assessed using iodine reagent and X-ray diffraction. The complexing reaction at 75 °C for 60 min showed the highest complexing index of the tested conditions; the in vitro digestibility of ALC was lower than that of corn starch. White pan bread was prepared with ALCs and their characteristics, including appearance, loaf volume, and starch retrogradation during storage at room temperature for four days, were compared with those of control bread. With increasing ALC replacement concentrations, loaf volume and shape were significantly affected; however, starch retrogradation was significantly retarded and energy value decreased by ALC replacement. Overall, 50% replacement of shortening by ALC appeared to be a reasonable level for retaining the basic characteristics of the bread while retarding the staling process. These results indicate that ALCs may be potentially useful in the bakery industry for preparing low calorie and low-fat products.

For practical use of carbon nanotube (CNT) composites, especially in electronic applications, uniform dispersion of a high concentration of CNTs in a polymer matrix is a critical challenge. Three-roll milling is one of most reliable dispersion techniques. We investigate the effect of three-roll milling time on CNT length and the electrical properties of a CNT/polydimethylsiloxane composite film with 10 wt% CNTs. During the milling process, the CNT length is decreased from 10 to 1−4 μm by mechanical shear forces. The electrical conductivity increases after 1.5 min of milling owing to dispersion of the CNTs but decreases with increasing milling time owing to the decrease in the CNT length. Considering the changes in the electrical conductivity of the CNT composite and CNT length, we determined how to optimize the three-roll milling time to obtain a suitable dispersion state.

The uniform temperature distribution, one of the requirements for long-term durability, is essential for composite heaters. An analytical model for temperature distribution of a tube-type heater was derived, and it revealed that thickness uniformity is one order more important than intrinsic material properties such as density, heat capacity, and electrical conductivity of the heating tube. We introduced a circumferential shearing process to fabricate a flexible, seamless tube-type heating layer of carbon nanotube/silicone rubber composite with outstanding uniform distribution of thickness and temperature, which may be attributed to a shorter characteristic dimension in the circumferential direction than in the axial direction. The temperature uniformity was experimentally verified at various temperatures under heating. The difference in measured thickness and temperature in circumferential direction was within ±1.3~3.0% (for tavg = 352.7 μm) and ±1.1% (for Tavg = 138.8 °C), respectively, all over the heating tube. Therefore, the circumferential shearing process can be effective for cylindrical heaters, like a heating layer of a laser printer, which fuse toners onto papers during printing.

We report the enhanced electromagnetic interference (EMI) shielding properties of hybrid carbon nanotube (CNT) composites consisting of more than two kinds of fillers through the use of segregate conducting networks. An excluded volume was created by micro-sized silica particles that concentrate the CNT network, resulting in improved electrical conductivity and microwave properties. To achieve the optimal dispersion of CNTs and silica particles, high shear force was applied to the pre-cured composite mixture via three-roll milling. Depending on the micro-silica content ratio, we observed improved electrical conductivity and EMI shielding properties. For a quantitative comparison to observe the excluded-volume effects, a CNT composite without micro-silica was measured in parallel with the other sample.

In this study, analysis of sensing signal profiles was conducted focusing on the close relationship between electrical conductivity and signal intensity in surface treated poly(dimethylsiloxane)/carbon nanotube (PDMS/CNT) composite patches for the purpose of their practical application as flexible chemical sensors. The flexible PDMS/CNT composite patches were prepared from a PDMS/CNT mixture with a two-roll apparatus. It was found that the PDMS/CNT pads showed a high electrical conductivity (10−1 S/m) even at low CNT loading (0.6 wt %) and a contact angle range of 105–118°. The surface of the obtained PDMS/CNT composite patches was treated using a simple bio-conjugation method to incorporate beta-cyclodextrin (beta-CD) molecules onto the surface as a sensing medium, in order to detect a model compound (Methyl Paraben, MePRB). FT-IR spectra indicated that beta-cyclodextrin molecules were effectively introduced on the surface of the PDMS/CNT patches. It was shown that the sensor signal intensity was substantially dependent on the base current value, which increased with increasing CNT loading. Accordingly, the base current value was intimately associated with the electrical conductivity of the composite patches. On the other hand, the increase in current over the base current (ΔI/I0) obtained after the addition of the model compound was inversely proportional to the CNT content. In this way, analysis on the sensing signal profiles of the flexible chemical sensor system was conducted to determine a process window. This study is a very useful springboard for future research activities, as more profound studies are necessary to fully understand sensing signal profiles.

This paper investigates possible paths of East Asian Monetary Integration. After a brief analysis of current discussions on East Asian economic and monetary integration, the paper presents possible implications of Europe's EMU project for East Asia and the political economy of East Asia as constraints on East Asia's way towards monetary integration. The paper argues that whichever paths East Asia selects, countries in the region have to devise measures that can lead to stability convergence, which was the main success factor for the introduction of single currency in Europe. The paper also presents seven possible paths for East Asian monetary integration, and argues that only four of them are feasible strategic choices. The paper concludes that although all these four paths are potential candidates, they have to be complemented by additional policy instruments. The paper suggests these additional measures be targeted at intensifying stability convergence in East Asia, which was the most important prerequisite for a successful introduction of Euro, the single currency for twelve member countries of the European Union. After a brief efficiency and feasibility test the paper selected the option of "developing the Chiang Mai Initiative to a Multilateral Financing Scheme" as the best short- and medium-term strategy towards monetary integration.

Catalytic fast pyrolysis over HZSM-5 of red pepper stems, a representative agricultural residue material in the southern area of South Korea, was carried out. The SiO2/Al2O3 ratio of the catalyst were 23 and 280. Pyrolysis-gas chromatography/mass spectrometry was used to pyrolyze the pepper stem samples at 550 °C and directly analyze the product distribution. The main product species of the non-catalytic pyrolysis of pepper stems were phenolics, followed by oxygenates and acids. The production of aliphatic and aromatic hydrocarbons was marginal. On the contrary, catalytic pyrolysis over HZSM-5 reduced the fractions of phenolics and acids significantly, while considerably increasing the fractions of aliphatic and aromatic hydrocarbons. The catalytic activity of the HZSM-5 with a SiO2/Al2O3 ratio of 23 was much higher, owing to its much larger amount of strong Brønsted acid sites, than the one with a SiO2/Al2O3 ratio of 280. Conversion of carbohydrate via furans to aromatics over strong acid sites was observed, which was in good agreement with previous studies. This study suggests that the catalytic pyrolysis of lignin-rich biomass over acidic zeolite catalysts can be a promising method to produce valuable chemicals such as aromatic compounds. [ABSTRACT FROM AUTHOR]

The catalytic copyrolysis of waste particle board (WPB) and polypropylene (PP) was investigated for the first time over HY (5.1), HY (30), H-Beta and Ga/H-Beta catalysts. The catalysts were characterized by BET and NH3-TPD analyses. The catalytic pyrolysis of the WPB increased the production of gas products (CO, CO2, C1-C4) compared to non-catalytic pyrolysis. Acids and levoglucosan, which are the main components of bio-oil produced from non-catalytic pyrolysis, were converted to more valuable aromatics, phenolics, and furans through dehydration, deoxygenation and aromatization. The most abundant products from the copyrolysis of WPB and PP were large-molecular-mass hydrocarbons (=C10). However, catalytic copyrolysis increased the yields of small-molecular-mass hydrocarbons in the gasoline range, aromatics and phenolics. The water content in bio-oil was reduced significantly by copyrolysis with PP, contributing to the improvement in oil quality. HY (5.1) with the largest number of acid sites showed higher catalytic activity than HY (30) and H-Beta because the decomposition and reforming reactions during catalytic copyrolysis occurred on the acid sites of the catalysts. Ga/H-Beta showed even higher selectivity toward the aromatics than H-Beta despite the smaller quantity of acid sites, suggesting that Ga promoted the dehydrocyclization of the reaction intermediates. [ABSTRACT FROM AUTHOR]

Mutants with deletion mutations in the glg and mal gene clusters of Escherichia coli MC4100 were used to gain insight into glycogen and maitodextrin metabolism. Glycogen content, molecular mass, and branch chain distribution were analyzed in the wild type and in ΔmalP (encoding maltodextrin phosphorylase), ΔmalQ (encoding amylomaltase), ΔglgA (encoding glycogen synthase), and ΔglgA ΔmalP derivatives. The wild type showed increasing amounts of glycogen when grown on glucose, maltose, or maltodextrin. When strains were grown on maltose, the glycogen content was 20 times higher in the ΔmalP strain (0.97 mg/mg protein) than in the wild type (0.05 mg/mg protein). When strains were grown on glucose, the ΔmalP strain and the wild type had similar glycogen contents (0.04 mg/mg and 0.03 mg/mg protein, respectively). The ΔmalQ mutant did not grow on maltose but showed wild-type amounts of glycogen when grown on glucose, demonstrating the exclusive function of GlgA for glycogen synthesis in the absence of maltose metabolism. No glycogen was found in the ΔglgA and ΔglgA ΔmalP strains grown on glucose, but substantial amounts (0.18 and 1.0 mg/mg protein, respectively) were found when they were grown on maltodextrin. This demonstrates that the action of MalQ on maltose or maltodextrin can lead to the formation of glycogen and that MalP controls (inhibits) this pathway. In vitro, MalQ in the presence of GlgB (a branching enzyme) was able to form glycogen from maltose or linear maltodextrins. We propose a model of maltodextrin utilization for the formation of glycogen in the absence of glycogen synthase. [ABSTRACT FROM AUTHOR]