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Traditional indoor localization techniques typically rely on a single communication source such as RF signals, ultrasound, inertial sensors, and geomagnetic fields. In wireless sensor network (WSN), received signal strength (RSS) based approach is one of the most commonly used localization techniques. It is simple to implement and costly efficient, but the estimation accuracy is significantly reduced in non-line-of-sight (NLOS) conditions. pedestrian dead reckoning (PDR) uses inertial measurement unit (IMU) for location tracking. Its tracking accuracy is not affected by the interference in NLOS conditions, but the location error is accumulated in long distance tracking. We propose the RSS-based indoor localization algorithm combined with PDR location tracking for wireless sensor networks. The objective is to compensate the NLOS localization error by using PDR, while mitigating the accumulated error of PDR by using RSS-based localization method in LOS conditions. Lab scale experiment and large scale simulation results show that the proposed algorithm significantly reduce the location estimation errors in wireless sensor networks.

The advent of soft robotics has led to great advancements in robots, wearables, and even manufacturing processes by employing entirely soft-bodied systems that interact safely with any random surfaces while providing great mechanical compliance. Moreover, recent developments in soft robotics involve advances in transparent soft actuators and sensors that have made it possible to construct robots that can function in a visually and mechanically unobstructed manner, assisting the operations of robots and creating more applications in various fields. In this aspect, imperceptible soft robotics that mainly consist of optically transparent imperceptible hardware components is expected to constitute a new research focus in the forthcoming era of soft robotics. Here, the recent progress regarding extended imperceptible soft robotics is provided, including imperceptible transparent soft robotics (transparent soft actuators/sensors) and imperceptible nontransparent camouflage skins. Their principles, materials selections, and working mechanisms are discussed so that key challenges and perspectives in imperceptible soft robotic systems can be explored.

Copper nanowires (Cu NWs) are suitable material as an electrode for flexible, stretchable and wearable devices due to their excellent mechanical properties, high transparency, good conductivity, and low cost, but oxidation problem limits their practical use and application. In order to use Cu NWs as an electrode for advanced flexible, stretchable and wearable devices attached directly to the skin, the influence of the body temperature on the oxidation of Cu NWs needs to be investigated. In this paper, the oxidation behavior of Cu NWs at high temperature (more than 80 °C) as well as body temperature is studied which has been remained largely questionable to date, and an effective encapsulation method is proposed to prevent the oxidation of Cu NWs electrode in the range of body temperatures.

Selective laser sintering of metal nanoparticle ink is an attractive technology for the creation of metal layers at the microscale without any vacuum deposition process, yet its application to elastomer substrates has remained a highly challenging task. To address this issue, we introduced the shear-assisted laser transfer of metal nanoparticle ink by utilizing the difference in thermal expansion coefficients between the elastomer and the target metal electrode. The laser was focused and scanned across the absorbing metal nanoparticle ink layer that was in conformal contact with the elastomer with a high thermal expansion coefficient. The resultant shear stress at the interface assists the selective transfer of the sintered metal nanoparticle layer. We expect that the proposed method can be a competent fabrication route for a transparent conductor on elastomer substrates.

Background This study aimed to evaluate the current overall preventable trauma death rate (PTDR) in Korea and identify factors associated with preventable trauma death (PTD). Methods The target sample size for review was designed to be 1,131 deaths in 60 emergency medical institutions nationwide. The panels for the review comprised trauma specialists working at the regional trauma centers (RTCs); a total of 10 teams were formed. The PTDR and factors associated with PTD were analyzed statistically. Results Of the target cases, 943 were able to undergo panel review and be analyzed statistically. The PTDR was 30.5% (6.1% preventable and 24.4% possibly preventable). Those treated at a RTC showed a significantly lower PTDR than did those who were not (21.9% vs. 33.9%; P = 0.002). The PTDR was higher when patients were transferred from other hospitals than when they directly visited the last hospital (58.9% vs. 28.4%; P = 0.058; borderline significant). The PTDR increased gradually as the time from accident to death increased; a time of more than one day had a PTDR 14.99 times higher than when transferred within one hour (95% confidence interval, 4.68 to 47.98). Conclusion Although the PTDR in Korea is still high compared to that in developed countries, it was lower when the time spent from the accident to the death was shorter and the final destined institution was the RTC. To reduce PTDR, it is necessary to make an effort to transfer trauma patients to RTCs directly within an appropriate time., Graphical Abstract

In this Letter, we report the development of a continuously tunable color filter based on a self-assembled isotropically stretchable microbead monolayer. Spreading equidistantly upon the application of lateral strain, the isotropically stretchable monolayer serves as a dynamic diffraction grating whose diffraction angle can be mechanically modulated. Combined with a simple spatial filtering scheme, the spectra of the filtered light are solely controlled by external strain (up to 32% radial strain) to cover a broad visible spectrum. Through a finite-difference time-domain far-field diffraction simulation, we validate the working principle of the proposed color filter. The proposed continuously tunable color filter is expected to open original applications in next-generation display field.

The rapid and sensitive detection of pathogen DNA (Deoxyribonucleic acid) would be essential for diagnosis and appropriate antibiotic treatment time. Herein, we report a novel direct DNA detectable impedimetric sensor. Direct assay of the amplified target DNA (mecA gene from methicillin-resistant Staphylococcus aureus (MRSA)) was performed using the PCR (polymerase chain reaction) product without any purification. Even though there are lots of PCR reagents and excess salts in sample PCR product, the nanogap electrode-based impedimetric sensor was able to detect DNA amplification fast in 5th PCR cycle which had 260 fM mecA gene in sample originally. The 70 nm gap electrode sensor yielded over 20% signal increase at the 5th PCR cycle and the impedance change grew up to about 60% at 25th in case of sample with 260 fM mecA gene template originally. The increased concentration of target DNA template led to the rise in impedance change such as 60% up at 5th and 120% up at 25th cycle with 260 pM, respectively. It is very outstanding result as compared with the traditional PCR agarose gel. Besides, it is 7-fold superior sensitivity to the microgap electrode. Furthermore, genomic DNA sample extracted from MRSA was detected rapidly. The nanogap electrode-based impedimetric sensor could be a good candidate for a rapid, sensitive, and low-cost electrical biosensor for DNA characterization in diagnostics and disease monitoring.

A highly stretchable and transparent electrical heater is demonstrated by constructing a partially embedded silver nanowire percolative network on an elastic substrate. The stretchable network heater is applied on human wrists under real-time strain, bending, and twisting, and has potential for lightweight, biocompatible, and versatile wearable applications.

Polymerase chain reaction (PCR) has been widely used for major definite diagnostic tool, but very limited its place used only indoor such as hospital or diagnosis lab. For the rapid on-site detection of pathogen in an outdoor environment, a low-power cordless polymerase chain reaction (PCR) thermal cycler is crucial module. At this point of view, we proposed a low-power PCR thermal cycler that could be operated in an outdoor anywhere. The disposable PCR chip was made of a polymeric (PI/PET) film to reduce the thermal mass. A dual arrangement of the Pt heaters, which were positioned on the top and bottom of the PCR chip, improved the temperature uniformity. The temperature sensor, which was made of the same material as the heater, utilized the temperature dependence of the Pt resistor to ensure simple fabrication of the temperature sensor. Cooling the PCR chip using dual blower fans enabled thermal cycling to operate with a lower power than that of a Peltier element with a high power consumption. The PCR components were electrically connected to a control module that could be operated with a Li-ion battery (12 V), and the PCR conditions (temperature, time, cycle, etc.) were inputted on a touch screen. For 30 PCR cycles, the accumulated power consumption of heating and cooling was 7.3 Wh, which is easily available from a compact battery. Escherichia coli genomic DNA (510 bp) was amplified using the proposed PCR thermal cycler and the disposable PCR chip. A similar DNA amplification capability was confirmed using the proposed portable and low-power thermal cycler compared with a conventional thermal cycler.

Air quality has become a major public health issue in Asia including China, Korea, and India. Particulate matters are the major concern in air quality. We present the first environmental application demonstration of Ag nanowire percolation network for a novel, electrical type transparent, reusable, and active PM2.5 air filter although the Ag nanowire percolation network has been studied as a very promising transparent conductor in optoelectronics. Compared with previous particulate matter air filter study using relatively weaker short-range intermolecular force in polar polymeric nanofiber, Ag nanowire percolation network filters use stronger long-range electrostatic force to capture PM2.5, and they are highly efficient (>99.99%), transparent, working on an active mode, low power consumption, antibacterial, and reusable after simple washing. The proposed new particulate matter filter can be applied for a highly efficient, reusable, active and energy efficient filter for wearable electronics application.

Selective laser sintering enables the facile production of metal nanoparticle-based conductive layers on flexible substrates, but its application towards large-area electronics has remained questionable due to the limited throughput of the laser process that originates from the direct writing nature. In this study, modified optical schemes are introduced for the fabrication of (1) a densely patterned conductive layer and (2) a thin-film conductive layer without any patterns. In detail, a focusing lens is substituted by a micro lens array or a cylindrical lens to generate multiple beamlets or an extended focal line. The modified optical settings are found to be advantageous for the creation of repetitive conducting patterns or areal sintering of the silver nanoparticle ink layer. It is further confirmed that these optical schemes are equally compatible with plastic substrates for its application towards large-area flexible electronics.

Here we tried to show the possibility of mechanical milling method for fabrication of SiC nanoparticles and ink-jet printing method to make SiC patterns for use as several applications, e.g., micro hotplates. Planetary milling was employed to fabricate the nano-scale SiC particles from coarse powders. After 100 hours of milling, the size of the SiC particles decreased to about 100 nm, which was sufficient for the formulation of ink for ink-jet printing. The SiC particles were dispersed in an ink system consisted of ethylene glycol and ethanol with a small amount of additives. The ink with SiC nanoparticles could be successfully printed on an alumina substrate by the ink-jet printing method.

ROOT HAIR SPECIFIC (RHS) genes, which contain the root hair-specific cis-element (RHE) in their regulatory regions, function in root hair morphogenesis. Here, we demonstrate that an Arabidopsis thaliana basic helix-loop-helix transcription factor, ROOT HAIR DEFECTVE SIX-LIKE4 (RSL4), directly binds to the RHE in vitro and in vivo, upregulates RHS genes, and stimulates root hair formation in Arabidopsis. Orthologs of RSL4 from a eudicot (poplar [Populus trichocarpa]), a monocot (rice [Oryza sativa]), and a lycophyte (Selaginella moellendorffii) each restored root hair growth in the Arabidopsis rsl4 mutant. In addition, the rice and S. moellendorffii RSL4 orthologs bound to the RHE in in vitro and in vivo assays. The RSL4 orthologous genes contain RHEs in their promoter regions, and RSL4 was able to bind to its own RHEs in vivo and amplify its own expression. This process likely provides a positive feedback loop for sustainable root hair growth. When RSL4 and its orthologs were expressed in cells in non-root-hair positions, they induced ectopic root hair growth, indicating that these genes are sufficient to specify root hair formation. Our results suggest that RSL4 mediates root hair formation by regulating RHS genes and that this mechanism is conserved throughout the tracheophyte (vascular plant) lineage.

In Korea, water supply and drainage noises result in one of the main noise complaints because more than 50% of people reside in multi-residential buildings. In this study, a series of field measurements were therefore carried out to examine the current noise situation. The noise levels were measured in the bathrooms of the upper and lower floors, as well as in habitable rooms. The measurement results for the bathrooms of the lower floor (N = 113) are 47.8 dBA (water closet), 42.7 dBA (basin), and 33.9 dBA (bathtub) for water drainage, while values vary between 33.7 dBA and 37.0 dBA for the water supply. The results suggest that the water drainage noise needs to be controlled first. The system bathroom (42.8 dBA) produced lower noise levels than the wet construction method (48.2 dBA) for all of the sanitary wares. The highest noise levels in the living rooms (N = 11) and bedrooms (N = 8) of the lower floor are 34.3 dBA and 39.1 dBA, respectively. The average noise level in the rooms (N = 19) is 37.8 dBA. The overall result suggests that it is necessary to develop an acoustic guideline to satisfy the higher Class of the 2nd ISO/CD 19488, although the current noise level satisfies Class C (living room) and Class D (bedroom).

A fundamental approach to fabricating a nonstick replica mold with high performance for the manufacturing of high-resolution nanostructures using mold-based lithography is presented. Low-viscosity liquid blends consisting of methacrylate multi-functionalized silsesquioxane (SSQMA), difunctional acrylics, and a small amount of silicone diacrylate (Si-DA) with low surface tension were used as nonstick replica-mold materials. The cured SSQMA/acrylic/Si-DA networks showed a high resistance to organic solvents ( 90% at 365 nm), hydrophobicity (water contact angle >90°), high modulus and wide-range modulus tunability (0.6–4.42 GPa) and small shrinkage (

Pluripotent stem cell–derived cardiomyocyte grafts can remuscularize substantial amounts of infarcted myocardium and beat in synchrony with the heart, but in some settings cause ventricular arrhythmias. It is unknown whether human cardiomyocytes can restore cardiac function in a physiologically relevant large animal model. Here we show that transplantation of ~750 million cryopreserved human embryonic stem cell–derived cardiomyocytes (hESC-CMs) enhances cardiac function in macaque monkeys with large myocardial infarctions. One month after hESC-CM transplantation, global left ventricular ejection fraction improved 10.6±0.9% vs. 2.5±0.8% in controls, and by 3 months there was an additional 12.4% improvement in treated vs. a 3.5% decline in controls. Grafts averaged 11.6% of infarct size, formed electromechanical junctions with the host heart and by 3 months contained ~99% ventricular myocytes. A subset of animals experienced graft-associated ventricular arrhythmias, shown by electrical mapping to originate from a point-source acting as an ectopic pacemaker. Our data demonstrate that remuscularization of the infarcted macaque heart with human myocardium provides durable improvement in left ventricular function.

To date, solar energy generation devices have been widely studied to meet a clean and sustainable energy source. Among them, water splitting photoelectrochemical cell is regarded as a promising energy generation way for splitting water molecules and generating hydrogen by sunlight. While many nanostructured metal oxides are considered as a candidate, most of them have an improper bandgap structure lowering energy transition efficiency. Herein, we introduce a novel wet-based, successive photoreduction process that can improve charge transfer efficiency by surface plasmon effect for a solar-driven water splitting device. The proposed process enables to fabricate ZnO/CuO/Ag or ZnO/CuO/Au hierarchical nanostructure, having an enhanced electrical, optical, photoelectrochemical property. The fabricated hierarchical nanostructures are demonstrated as a photocathode in the photoelectrochemical cell and characterized by using various analytic tools.

The interface between yttrium oxide partially stabilized tetragonal zirconia polycrystalline (Y-TZP) core and veneering porcelain is the site of most clinical failures. Many efforts have focused on increasing the bond strength between Y-TZP core and veneering porcelain, and such approaches include increasing the surface roughness and providing undercuts. However, each surface roughening method carries limitations. The specific aim of this study was to test the bond strengths of Y-TZP subjected to different methods (sandblasting, fine polising, and rough polising) and of veneering porcelain. Presintered zirconia blocks with rectangular parallelepiped shape were prepared, and the surfaces were roughened with different methods before sintering. Shear strength of each zirconia-veneer interface was measured from 15 specimens. The surface at the fractured areas after shear test was investigated using an optical microscope. In conclusion, Y-TZP subjected to sandblasting showed inferior shear strength compared to other groups. Cohesive fracture was observed in the sandblasting group; combination of cohesive and adhesive fracture was observed in the control, fine polishing, and rough polishing groups.

We report a new approach to fabricate nanochannels on silicon-on-insulator (SOI) wafers using conventional micromachining techniques. Proper selection of the size of the photomask-window and the thickness of the top silicon layer is necessary to obtain nano-sized regions. Silicon anisotropic wet etching followed by an additional reactive-ion-etching (RIE) process and a second silicon wet etching step resulted in long channels (1 cm) of about 200 nm width and 100 nm depth. Finally, we demonstrated the ability of the nanochannels to stretch random coiled DNA by applying YOYO-1 stained lamda-DNA to the nanochannel sealed by PDMS polymer using fluorescence microscopy. This fabrication method provides a basis for simple and cost-effective mass production of nanochannels with controllable dimensions. It is therefore expected that the nanochannels fabricated have great potential for biological applications.

Using a solenoid-driven fast sampling system and gas chromatography (GC), the profiles of unburned hydrocarbons (HCs) and non-fuel HCs in a propane-fueled-engine were obtained at several positions in the exhaust port during the exhaust process. Changes in the total HC concentration and HC fractions of major components along the exhaust port are discussed and compared with other research results. The results show that the stratification of HC concentration exists around the exhaust valve. The increase of 10% in the fraction of non-fuel components along the exhaust port reflects significant HC oxidation. The results also show that a bulk gas with relatively high HC concentration comes out through the bottom of the exhaust valve. A cycle simulation and plug flow modeling were used to estimate the mass-averaged percentage of the HC oxidation in the exhaust port. Model predictions of HC oxidation are consistent with current and previous experimental results. The percentage of the HC oxidation in the exhaust po...

SiC nanoparticles were successfully fabricated by a high energy ball milling method, so that can be used in the printed electronics to make SiC thin film patterns. Here we utilized the waste of Si sludge for making the SiC nanoparticles. In order to achieve uniform thin film from the nanoparticle ink, fine sized SiC nanoparticles less than 100 nm has to be uniformly dispersed. In this study, we employed the ultra apex milling (UAM) system for particle comminution and dispersion. We investigated the effects of milling parameters, e.g., size of ZrO2 bead and milling time. The size of the SiC particles reached about 103 nm after 4 hours of UAM, when the ZrO2 beads of 50 microm were used. Then SiC ink was formulated with organic solvents and a dispersing agent. A specially designed pattern was printed by an ink-jet printer for evaluating the feasibility of the SiC nanoparticle inks.

Copper is a promising electronic material due to low cost and high electrical conductivity. However, the oxidation problem in an ambient condition creates a crucial issue in practical applications. In this paper, a simple and cost-effective Cu patterning method has been developed on flexible PET film by combining a solution processable Cu nanoparticle patterning and a low-temperature postprocessing with acetic acid treatment, laser sintering process, and acid-assisted laser sintering process. The acid-assisted laser sintering processed Cu electrode shows superior characteristics in electrical, mechanical, and chemical stability over other postprocessing methods. Finally, the Cu electrode is applied to flexible electronics applications such as flexible and transparent heaters and touch screen panels.

A novel maskless fabrication method for highly flexible Cu random network transparent conductor has been developed by random nanocrack generation and subsequent Cu nanoparticle ink filling, transfer, and oxidation-free laser sintering without the aid of conventional photolithography or vacuum metal deposition steps. Use of random nanocrack on a silicon as a transfer printing template enables large area, high resolution network patterning, and fabrication in a simple maskless manner. At the same time, the laser sintering process allows low temperature, fast processing time, and oxidation suppression of Cu nanoparticle under ambient atmosphere. The fabricated Cu metal network establishes strong adhesion to plastic substrates, thus mechanical stability against tensile and compressive bending is attainable. Moreover, the template-assisted Cu metal network fabrication method minimizes waste of Cu nanoparticle as compared with other methods. A simple touch screen using Cu metal network-based transparent conductor is also demonstrated.

As our global society has been more complex and connected closely, infectious diseases could be easily and fast propagated to everywhere. And it makes early diagnostic detection be necessary with various ways based on optical, electrical and electrochemical methods. Real-time PCR (Polymerase Chain Reaction) has been powerful detection technology to recognize the amplified target DNA fragments that would be essential to diagnostic assays, but it needs optical labels and apparatus to detect the amplification of DNA. A variety of electric/electrochemical methods have been applied for label-free detection. Impedance assay is attractive tool for biomolecule real-time sensing, however, most of impedance studies are based on the immobilization of biomolecules on the electrode surface. That ascribes to additional steps and makes impossible to reuse electrode chip and biological samples. In this study, we aimed to develop the electrical impedance detection not optical method measuring the bulk impedance of PCR product solution by nanogap electrode. Electrical impedimetric nanogap devices could be very useful for detecting slight changes of amplifying DNA fragments in PCR cycling due to double layer capacitance and charge transfer resistance between two opposing nanogap electrodes. The electrode chip was fabricated using gold thin film by easy photolithography designed the nanogapped Si/SiO2 substrate by evaporation of oxide materials. Applying electric impedance measuring in nanogap chip avoiding the use of optical labels and immobilization on the electrode surface would be very impact detection system on DNA real-time screening.

We introduce a scanometric detection method for the analysis of DNA microarrays using DNA intercalator-conjugated gold nanoparticles that can be analyzed with the naked eye or with an optical scanner after the enhancement of the AuNPs. Moreover, we successfully detected a hemagglutinin-subtyping DNA array using this method.

For the electrical detection of target DNA (partial avian influenza virus/H1N1/HA sequence) prepared via asymmetric PCR, we fabricated DNA-templated conducting gold nanowire bridges on planar nanogap electrodes using positively charged gold nanoparticles.

As the first study which introduce and examine supervisor knowledge sharing, this study investigated both the positive and negative aspects of supervisor knowledge sharing. Our findings, from field...

This field study investigated the interaction effects of an employee personality trait (learning goal orientation) and a social exchange relationship (psychological contract breach) on knowledge sh...

Utilizing a gold enhancement process after inducing electrostatic interaction between positively charged gold nanoparticles and negatively charged target DNA hybridized to neutral PNA capture probes, a new method for label-free detection of DNA was developed and successfully applied to detect H5-type DNA.

We demonstrate nanogap biosensors for electrical and label-free detection of biomolecular interactions. Parallel fabrication of nanometer distance gaps has been achieved using a silicon anisotropic wet etching technique on a silicon-on-insulator (SOI) wafer with a finely controllable silicon device layer. Since silicon anisotropic wet etching resulted in a trapezoid-shaped structure whose end became narrower during the etching, the nanogap structure was simply fabricated on the device layer of a SOI wafer. The nanogap devices were individually addressable and a gap size of less than 60 nm was obtained. We demonstrate that the nanogap biosensors can electrically detect biomolecular interactions such as biotin/streptavidin and antigen/antibody pairs. The nanogap devices show a current increase when the proteins are bound to the surface. The current increases proportionally depending upon the concentrations of the molecules in the range of 100 fg ml(-1)-100 ng ml(-1) at 1 V bias. It is expected that the nanogap developed here could be a highly sensitive biosensor platform for label-free detection of biomolecular interactions.

A new equalization method for Blu-ray (BR) recording channels is proposed. The proposed equalizer incorporates the Gaussian sum approximation (GSA) into a Kalman filtering framework to mitigate intersymbol interference in BR recording systems. The proposed equalizer consists of a bank of linear equalizers using the Kalman filtering algorithm and its output is obtained by combining the outputs of linear equalizers through the GSA. The proposed equalizer shows a better performance than the conventional equalizers and a similar performance with the only equalization technique to the partial response maximum likelihood methods in terms of bit-error-rate.

International audience; We developed a reusable magnetic surface plasmon resonance (SPR) sensor chip for detecting various target molecules repeatedly in a conventional SPR system. Here, ferromagnetic patterns on a SPR sensor chip were utilized to trap a layer of magnetic particles, and they were utilized as a solid substrate for SPR sensing in a conventional SPR system. After a sensing experiment, the used magnetic particles were removed by external magnetic fields, and a new layer of magnetic particles was immobilized to the SPR sensor chip for additional sensing measurements. Since magnetic particles were trapped on the ferromagnetic patterns, we could use our reusable SPR chip for SPR sensing measurements in a traditional SPR system without any applied magnetic fields. Significantly, ferromagnetic patterns on the sensor chip surface deflected the strong external fields, so that the large aggregation of magnetic particles on the sensor surface was reduced. We demonstrated using a single reusable SPR sensor chip to measure the nucleoprotein (NP) of H1N1 influenza virus solution ranging repeatedly for more than 7 times without significant signal degradation. Also, different target molecules could be repeatedly measured in a single SPR chip. Since our reusable SPR sensor chip can be repeatedly used in a conventional SPR system without any chemical processes for refreshment, the cost for SPR sensing should be significantly reduced. In this case, our reusable SPR sensor chip can be a major breakthrough and can be used for versatile practical applications of SPR sensors.