A Multilayered GaAs IPD Resonator with Five Airbridges for Sensor System Application.

This work proposes a microwave resonator built from gallium arsenide using integrated passive device (IPD) technology. It consists of a three-layered interlaced spiral structure with airbridges and inner interdigital structures. For integrated systems, IPD technology demonstrated outstanding performance, robustness, and a tiny size at a low cost. The airbridges were made more compact, with overall dimensions of 1590 × 800 µm2 (0.038 × 0.019 λg2). The designed microwave resonator operated at 1.99 GHz with a return loss of 39 dB, an insertion loss of 0.07 dB, and a quality factor of 1.15. Additionally, an experiment was conducted on the properties of the airbridge and how they affected resistance, inductance, and S-parameters in the construction of the resonator. To investigate the impact of airbridges on the structure, E- and H-field distributions of the resonator were simulated. Furthermore, its use in sensing applications was explored. Various concentrations of glucose solutions were used in the experiment. The proposed device featured a minimum detectable concentration of 0.2 mg/mL; high sensitivity, namely, 14.58 MHz/mg·mL-1, with a linear response; and a short response time. Thus, this work proposes a structure that exhibits potential in integrated systems and real-time sensing systems with high sensitivity.

Measurement of Complex Permittivity for Rapid Detection of Liquid Concentration Using a Reusable Octagon-Shaped Resonator Sensor.

Substrate-integrated waveguides (SIWs) are widely used in microwave systems owing to their low cost and ease of integration. In this study, an SIW-based resonator that reacts to the complex permittivity variation of solutions with dimensions of 79.2 mm × 59.8 mm is introduced. This octagon-shaped sensor can be installed on a preliminary monitoring system to test water quality by observing the parameter variations caused by external factors. The resonant structure was used to test different concentrations of ethanol-water and acetone-water mixtures for verification. The resonant frequency and quality factor (Q-factor) were found to vary with the relative complex permittivity of the liquid in the S-band, and the electric field distribution varied when liquid droplets were placed in the center of the substrate. The designed sensor operates at 2.45 GHz in the air, and the observed minimum resonant frequency shift with liquid was 15 MHz. The measurement error was approximately 3.1%, and the results reveal a relationship between the resonant frequency and temperature as well. Considering the observed sources of error, the measured relative permittivity is consistent with the actual values. The proposed sensor is economically convenient and suitable for various test environments.

Incorporating Wireless Strategies to Wearable Devices Enabled by a Photocurable Hydrogel for Monitoring Pressure Information.

Advances in emerging technologies for wireless collection and the timely analysis of various information captured by wearable devices are of growing interest. Herein, a crosslinked ionic hydrogel prepared by a facile photocuring process is proposed, which allows wearable devices to be further incorporated into two wireless integrated systems for pressure monitoring applications. The device exhibits a simplified structure by effectively sharing functional layers, rather than conventional two separate combinations, offering the salient performance of iontronic sensing and electrochromic properties to simultaneously quantify and visualize pressure. The developed smart patch system is demonstrated to monitor physiological signals in real-time utilizing the user interface of remote portable equipment with the Bluetooth protocol and on-site electrochromic displays. Moreover, a passive wireless system based on the magnetic coupling effect is designed, which can operate free from the battery and simultaneously acquire multiple pressure information. It is envisioned that the strategies would hold enormous potential for flexible electronics, versatile sensing platforms, and wireless on-body networks.

The mitochondrial genome of Stereolepis doederleini (Pempheriformes: Polyprionidae) and mitogenomic phylogeny of Pempheriformes.

The complete mitochondrial (mt) genome of Stereolepis doederleini was sequenced from a specimen collected in a commercial aquarium in Jeju Island. The sequence was 16,513 base pairs in length and, similar to other vertebrate mt genomes, included 37 mt genes and a noncoding control region; the gene order was identical to that of typical vertebrate mt genome. Mitochondrial genome sequences of 17 species from 12 families were used to reconstruct phylogenetic relationships within the order Pempheriformes. The phylogenetic trees were constructed with three methods (neighbor joining [NJ], maximum likelihood [ML], and Bayesian method) using 12 protein coding genes, but not ND6. In all phylogenetic trees, Pempheriformes were clustered into three strongly supported clades. Two Acropomatidae species (Synagrops japonicus in clade-Ⅰ and Doederleinia berycoides in clade-Ⅲ) were polyphyletic; S. japonicus was close to Lateolabracidae and was the sister of Glaucosomatidae + (Pempheridae/(Percophidae+Creediidae)), and D. berycoides was sister to Howellidae + Epigonidae. All phylogenetic trees supported a sister relationship between Creediidae and Percophidae in clade-Ⅰ. Glaucosomatidae formed a sister clade with Pempheridae. The relationships within clade-Ⅱ, which was composed of four families (Pentacerotidae, Polyprionidae, Banjosidae, and Bathyclupeidae), slightly differed between NJ/ML and BI tree topologies. In clade-Ⅲ, the relationships among Howellidae, Epigonidae, and Acropomatidae were strongly supported.

Report on a New Truffle Species, Tuber koreanum sp. nov., from Korea.

The truffle and ectomycorrhizal roots formed by Tuber sp. were collected from the rhizosphere of Quercus aliena in Korea. The morphological characteristics of the ascoma, and molecular phylogenetic analysis using sequences from the internal transcribed spacer (ITS) and large subunit (LSU) of ribosomal DNA, translation elongation factor 1-alpha (TEF), and RNA polymerase second largest subunit (RPB2) regions confirmed the distinct morphology of the truffle. This truffle belongs to a monophyletic clade among the other Tuber species in the phylogeny. This study describes the truffle, Tuber koreanum, as a new species reported from Korea.

Computations on the Thermal Characteristics of SF6 and CO2 Switching Arcs on a Microscopic Scale.

Pure sulfur hexafluoride is a colorless, odorless, non-toxic, inflammable, chemically inert and thermally stable gas and has proven its worth as an excellent interruption and dielectric medium. SF6 has been successfully used for interruption and insulation purposes as interrupters and circuit-breakers in gas-insulated substations. Due to its long lifetime and high global warming potential, this gas was put on the list of fluorinated greenhouse gases in the Kyoto Protocol aimed at controlling the emission of man-made greenhouse gases. This factor makes the search for an environmentally friendly alternative to SF6 all the more urgent. In this paper, we conducted computations on the thermal and aerodynamic behaviors of SF6 and an alternative CO2 switching arcs in a self-blast chamber in order to compare the switching phenomena and the thermal reignition from an engineering point of view. Through the complete work, the 3,000 K isotherm of the remnant arc column within microseconds after a current zero was used to evaluate the thermal reignition of SF6 and CO2 switching arcs with the slope of the tangential line of the transient recovery voltage on a microscopic scale.

Preparation of Pyridylamido Hafnium Complexes for Coordinative Chain Transfer Polymerization.

The pyridylamido hafnium complex (I) discovered at Dow is a flagship catalyst among postmetallocenes, which are used in the polyolefin industry for PO-chain growth from a chain transfer agent, dialkylzinc. In the present work, with the aim to block a possible deactivation process in prototype compound I, the corresponding derivatives were prepared. A series of pyridylamido Hf complexes were prepared by replacing the 2,6-diisopropylphenylamido part in I with various 2,6-R2C6H3N-moieties (R = cycloheptyl, cyclohexyl, cyclopentyl, 3-pentyl, ethyl, or Ph) or by replacing 2-iPrC6H4C(H)- in I with the simple PhC(H)-moiety. The isopropyl substituent in the 2-iPrC6H4C(H)-moiety influences not only the geometry of the structures (revealed by X-ray crystallography), but also catalytic performance. In the complexes bearing the 2-iPrC6H4C(H)-moiety, the chelation framework forms a plane; however, this framework is distorted in the complexes containing the PhC(H)-moiety. The ability to incorporate α-olefin decreased upon replacing 2-iPrC6H4C(H)-with the PhC(H)-moiety. The complexes carrying the 2,6-di(cycloheptyl)phenylamido or 2,6-di(cyclohexyl)phenylamido moiety (replacing the 2,6-diisopropylphenylamido part in I) showed somewhat higher activity with greater longevity than did prototype catalyst I.

Polystyrene Chain Growth Initiated from Dialkylzinc for Synthesis of Polyolefin-Polystyrene Block Copolymers.

Polyolefins (POs) are the most abundant polymers. However, synthesis of PO-based block copolymers has only rarely been achieved. We aimed to synthesize various PO-based block copolymers by coordinative chain transfer polymerization (CCTP) followed by anionic polymerization in one-pot via conversion of the CCTP product (polyolefinyl)2Zn to polyolefinyl-Li. The addition of 2 equiv t-BuLi to (1-octyl)2Zn (a model compound of (polyolefinyl)2Zn) and selective removal or decomposition of (tBu)2Zn by evacuation or heating at 130 °C afforded 1-octyl-Li. Attempts to convert (polyolefinyl)2Zn to polyolefinyl-Li were unsuccessful. However, polystyrene (PS) chains were efficiently grown from (polyolefinyl)2Zn; the addition of styrene monomers after treatment with t-BuLi and pentamethyldiethylenetriamine (PMDTA) in the presence of residual olefin monomers afforded PO-block-PSs. Organolithium species that might be generated in the pot of t-BuLi, PMDTA, and olefin monomers, i.e., [Me2NCH2CH2N(Me)CH2CH2N(Me)CH2Li, Me2NCH2CH2N(Me)Li·(PMDTA), pentylallyl-Li⋅(PMDTA)], as well as PhLi⋅(PMDTA), were screened as initiators to grow PS chains from (1-hexyl)2Zn, as well as from (polyolefinyl)2Zn. Pentylallyl-Li⋅(PMDTA) was the best initiator. The Mn values increased substantially after the styrene polymerization with some generation of homo-PSs (27-29%). The Mn values of the extracted homo-PS suggested that PS chains were grown mainly from polyolefinyl groups in [(polyolefinyl)2(pentylallyl)Zn]-[Li⋅(PMDTA)]+ formed by pentylallyl-Li⋅(PMDTA) acting onto (polyolefinyl)2Zn.

Quasi-Three-Dimensional Computations of the Microscopic Thermal and Dielectric Characteristics of an SF6 Rotating Switching Arc.

Pure sulfur hexafluoride (SF6) is chemically inert, non-flammable, non-toxic and thermally stable, and it has excellent dielectric strength and arc-quenching and control properties. The switching-off process of SF6 arc discharges occurs at the region between the contacts during the opening sequence to interrupt the flow of excessive current in a faulty network. The arc is tolerated in a controlled manner until a natural current zero when the arc discharge is rapidly quenched to restrict the thermal and dielectric reignition to the interruption. An SF6 self-blast switching chamber combines two advantages of blowing by heat expansion of the SF6 and arc rotation by electromagnetic effect of coil to improve the switching performance on thermal and dielectric reignition. The thermal and aerodynamic behaviors of an SF6 rotating switching arc in the chamber physically are complex and difficult to understand only by measurement due to their three-dimensional effects. Since the late nineteen-eighties, significant progress has been made in the method of computational fluid dynamics describing the physical processes occurring in the switching arc. The final goal of computer simulation technology on the arc switching is to predict the switching phenomena on the thermal and dielectric reignition from an engineering point of view. In this paper, we have conducted quasi-three dimensional computations to predict the thermal and dielectric reignition of SF6 rotating arcs occurring after a current zero in the self-blast switching chamber. Through the complete work, the microscopic thermal and aerodynamic behaviors of the remnant arc column after a current zero should be good criteria to predict the thermal and dielectric reignition of the rotating switching arc in the chamber.

Feasibility Study on a Segmented Ferrofluid Flow Linear Generator for Increasing the Time-Varying Magnetic Flux.

Nanoparticles and nanofluids have been implemented in energy harvesting devices, and energy harvesting based on magnetic nanofluid flow was recently achieved by using a layer-built magnet and micro-bubble injection to induce a voltage on the order of 10-1 mV. However, this is not yet suitable for some commercial purpose. In order to further increase the amount of electric voltage and current from this energy harvesting the air bubbles must be segmented in the base fluid, and the magnetic flux of the segmented flow should be materially altered over time. The focus of this research is on the development of a segmented ferrofluid flow linear generator that would scavenge electrical power from waste heat. Experiments were conducted to obtain the induced voltage, which was generated by moving a ferrofluid-filled capsule inside a multi-turn coil. Computations were then performed to explain the fundamental physical basis of the motion of the segmented flow of the ferrofluids and the air-layers.

Numerical Simulation on the Induced Voltage Across the Coil Terminal by the Segmented Flow of Ferrofluid and Air-Layer.

Nanoparticles and nanofluids have been implemented in energy harvesting devices, and energy harvesting based on magnetic nanofluid flow was recently achieved by using a layer-built magnet and microbubble injection to induce a voltage on the order of 10-1 mV. However, this is not yet suitable for some commercial purpose. The air bubbles must be segmented in the base fluid, and the magnetic flux of the ferrofluids should change over time to increase the amount of electric voltage and current from energy harvesting. In this study, we proposed a novel technique to achieve segmented flow of the ferrofluids and the air layers. This segmented ferrofluid flow linear generator can increase the magnitude of the induced voltage from the energy harvesting system. In our experiments, a ferrofluid-filled capsule produced time-dependent changes in the magnetic flux through a multi-turn coil, and the induced voltage was generated on the order of about 101 mV at a low frequency of 2 Hz. A finite element analysis was used to describe the time-dependent change of the magnetic flux through the coil according to the motion of the segmented flow of the ferrofluid and the air-layer, and the induced voltage was generated to the order of 102 mV at a high frequency of 12.5 Hz.

Interaction Model Between an Electrical Arc and a Material for Arc Discharge Synthesis of Metal Nanoparticles.

Metal nanoparticles are used in applications ranging from bio-diagnostics to catalysis due to the expectation to improve attributes or the performance of specific products or processes. The electric arc can be used to produce metal nanoparticles by evaporating the anode and forming the anode vapor. In order to synthesize the nanoparticles of the desired properties, the influence of various input parameters on the growth kinetics has to be fully understood. In this study, we presented two and three dimensional results of numerical simulation of the transferred electric arc taking into account the interaction model between an electric arc and two electrodes. It was found that the predicted temperature of the arc column with two electrodes was in good agreement with the measured data, and the main advantage of this model over our previous one was to predict the temperature distribution of the arc column with two electrodes by two- and three-dimensional computations.

Two-Dimensional Computations on the Thermal Behaviors Between Arc Plasmas and Their Electrodes for the Switching Chamber Design.

A SF6 self-blast switching chamber belongs to a new generation of high-voltage switching devices, which take advantage of the auto-expansion principle and arc rotation to improve the switching performance on thermal and dielectric interruptions. The thermal behaviors between the arc plasma and the electrodes in the device are very complex to understand only through experimental studies. Since the late nineteen-eighties, significant progress has been made in computational methods describing the physical processes occurring in thermal plasmas. The final goal of a computer simulation on thermal plasmas is to predict the switching performance on thermal and dielectric interruptions from an engineering point of view. In this paper, we have conducted computations to predict the thermal and dielectric breakdown capabilities of a SF6 self-blast switching chamber from the results of the thermal behaviors during the entire switching process, such as a high-current period, pre-current zero period, and current-zero period. Through the complete work, the temperature of the residual thermal plasmas as well as the breakdown index after the current zero should be good criteria to predict the thermal and dielectric capabilities of the switching chambers.

Numerical Study on Alternating Current Breakdown Mechanism Between Sphere-Sphere Electrodes in Transformer Oil-Based Magnetic Nanofluids.

A numerical simulation was developed for magnetic nanoparticles in a liquid dielectric to investigate the AC breakdown voltage of the magnetic nanofluids according to the volume concentration of the magnetic nanoparticles. In prior research, we found that the dielectric breakdown voltage of the transformer oil-based magnetic nanofluids was positively or negatively affected according to the amount of magnetic nanoparticles under a testing condition of dielectric fluids, and the trajectory of the magnetic nanoparticles in a fabricated chip was visualized to verify the related phenomena via measurements and computations. In this study, a numerical simulation of magnetic nanoparticles in an insulating fluid was developed to model particle tracing for AC breakdown mechanisms happened to a sphere-sphere electrode configuration and to propose a possible mechanism regarding the change in the breakdown strength due to the behavior of the magnetic nanoparticles with different applied voltages.

Evaluation of Infection after Anterior Cruciate Ligament Reconstruction during a Short Period.

PURPOSE: We encountered 7 cases (7.1%) of infection (5 deep and 2 superficial) in 98 cases of anterior cruciate ligament (ACL) reconstruction using hamstring autografts in a 17-month period. The aim of this study was to analyze the causes of infection and to introduce our treatment strategy. MATERIALS AND METHODS: We investigated the shelf-life of the fixation implants, the order of surgery, previous knee surgery, infectious pathogen, treatment of infection, and results of treatment. RESULTS: There was no problem with the expiration date of the fixation implants. The order of surgery was either the last or second to the last of all those performed on the same day. One patient had undergone knee surgery 8 months previously. The treatment after infection included aggressive debridement in all cases. Revision ACL reconstruction with graft removal was performed in 1 case of persistent infection with methicillin-resistant Staphylococcus aureus. All cases had satisfactory clinical results without recurrence during a mean 24.9 months of follow-up. CONCLUSIONS: We could not verify the exact cause of the high incidence of infection during the 17-month period. However, preventive measures are important to decrease the incidence of infection after ACL reconstruction.

Anti-inflammatory activities of Dangyuja (Citrus grandis Osbeck) in concanavalin A stimulated murine splenocytes and 12-O-tetradecanoylphorbol-13-acetate-induced murine skin edema.

Dangyuja (Citrus grandis Osbeck), a citrus cultivated in southern Korea, has been used in traditional medicine for its anti-inflammatory effect. In this study, we investigated the anti-inflammatory potential of extract of Citrus grandis Osbeck (ECGO). In in vitro assays, ECGO treatment of concanavalin A (10µg/ml, for 24h) stimulated splenocytes showed significant reduction in CD44/CD62L+ T cell population and a marked decrease in the production of inflammatory cytokines IL-2, IFN-γ and IL-4. Interestingly, in vivo assays of ECGO topical treatment (100µg/20µl/ear) significantly mitigated the TPA (4µg/20µl/ear) induced edema induction and Myeloperoxidase activity. Anti-inflammatory potential of ECGO were further evidenced through its potent decrease in expression of inducible nitric oxide, cyclooxygenase-2, IL-1ß and TNF-α and suppressed homing of CD3+ T cells and F4/80+ macrophages to site of inflammation. This study emphasizes the possibility of developing ECGO as an alternative natural topical agent to combat inflammatory diseases.

Citrus hallabong [(Citrus unshiu × C. sinensis) × C. reticulata)] exerts potent anti-inflammatory properties in murine splenocytes and TPA-induced murine ear oedema model.

CONTEXT: Hallabong [(Citrus unshiu × C. sinensis) X C. reticulata)] (Rutaceae) is a hybrid citrus cultivated in temperate regions of South Korea. Its fruit is well-known for pharmacological properties. OBJECTIVE: This study examined the anti-inflammatory effect of 80% ethanol extract of Hallabong (HE) on concanavalin A (Con A)-stimulated splenocytes and mouse oedema model induced by 12-O-tetradecanoylphorbal acetate (TPA). MATERIALS AND METHODS: Murine splenocytes treated with HE were stimulated with Con A (10 µg/mL, for 24 h) were evaluated for T-cell population and production of inflammatory cytokines IL-2, IL-4 and IFN-γ. Anti-inflammatory effect of topically applied HE (100 µg/20 µL) on TPA (4 µg/20 µL/ear)-induced ear oedema was investigated in mouse model. RESULTS: HE-treated Con A-stimulated murine splenocytes showed a marked decrease in CD44/CD62L+ memory T-cell population, an important marker for anti-inflammatory activity, and a significant inhibition in the production of IL-2 and IFN-γ. HE treatment had reduced the mouse skin oedema (47%) and myeloperoxidase (MPO) activity significantly (40%) in TPA-challenged tissues. More importantly, immunohistochemical localization revealed the suppressed (p < 0.05) expression of inducible nitric oxide (iNOS), cyclooxygenase-2 (COX2). HE decreased the infiltration of CD3+ T cells and F4/80+ macrophages to the site of inflammation and a topical application of HE significantly suppressed the expression of TNF-α (20.2%). DISCUSSION AND CONCLUSION: A topical application of HE can exert a potential anti-inflammatory effect and HE can be explored further as a putative alternative therapeutic agent for inflammatory oedema.

Elastic nailing of tibia shaft fractures in young children up to 10 years of age.

INTRODUCTION: Although tibia shaft fractures in children usually have satisfactory results after closed reduction and casting, there are several surgical indications, including associated fractures and soft tissue injuries such as open fractures. Titanium elastic nails (TENs) are often used for pediatric tibia fractures, and have the advantage of preserving the open physis. However, complications such as delayed union or nonunion are not uncommon in older children or open fractures. In the present study, we evaluated children up to 10 years of age with closed or open tibial shaft fractures treated with elastic nailing technique. METHODS: A total of 16 tibia shaft fractures treated by elastic nailing from 2001 to 2013 were reviewed. The mean patient age at operation was 7 years (range: 5-10 years). Thirteen of 16 cases were open fractures (grade I: 4, grade II: 6, grade IIIA: 3 cases); the other cases had associated fractures that necessitated operative treatments. Closed, antegrade intramedullary nailing was used to insert two nails through the proximal tibial metaphysis. All patients were followed up for at least one year after the injury. Outcomes were evaluated using modified Flynn's criteria, including union, alignment, leg length discrepancies, and complications. RESULTS: All fractures achieved union a mean of 16.1 weeks after surgery (range: 11-26 weeks). No patient reported knee pain or experienced any loss of knee or ankle motion. There was a case of superficial infection in a patient with grade III open fracture. Three patients reported soft tissue discomfort due to prominent TEN tips at the proximal insertion site, which required cutting the tip before union or removing the nail after union. At the last follow-up, there were no angular or rotational deformities over 10° in either the sagittal or coronal planes. With the exception of one case with an overgrowth of 15 mm, no patient showed shortening or overgrowth exceeding 10mm. Among final outcomes, 15 were excellent and 1 was satisfactory. SUMMARY: Even with open fractures or soft tissue injuries, elastic nailing can achieve satisfactory results in young children, with minimal complications of delayed bone healing, or infection.

Numerical Study on the Particle Trajectory Tracking in a Micro-UV Bio-Fluorescence Sensor.

A micro-UV bio-fluorescence sensor was developed to detect primary biological aerosols including bacteria, bacterial spores, fungal spores, pollens, viruses, algae, etc. In order to effectively detect the bio-particles in a micro-UV bio-fluorescence sensor, numerical calculations were performed to adjust for appropriate flow conditions of the sensor by regulating the sample aerosols and sheath flow. In particular, a CFD-based model of hydrodynamic processes was developed by computing the trajectory of particles using commercially available ANSYS CFX-14 software and the Lagrangian tracking model. The established model was evaluated with regard to the variation of sheath flow rate and particle size. Results showed that the sheath flow was changed rapidly at the end of nozzle tip, but the sample particles moved near the center of aerosol jet for aerodynamic focusing with little deviation from the axis.

Temperature Prediction in a Free-Burning Arc and Electrodes for Nanostructured Materials and Systems.

Temperature in a free-burning arc used for synthesis of nanoparticles and nanostructured materials is generally around 20,000 K just below the cathode, falling to about 15,000 K just above the anode, and decreasing rapidly in the radial direction. Therefore, the electrode erosion is indispensable for these atmospheric plasma systems, as well as for switching devices, due to the high heat flux transferred from high temperature arcs to electrodes, but experimental and theoretical works have not identified the characteristic phenomena because of the complex physical processes. To the previous study, we have focused on the arc self-induced fluid flow in a free-burning arc using the computational fluid dynamics (CFD) technique. At this time, our investigation is concerned with the whole region of free-burning high-intensity arcs including the tungsten cathode, the arc plasma and the anode using a unified numerical model for applying synthesis of nanoparticles and nanostructured materials practically.