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Artificial synapses for neuromorphic computing have been increasingly highlighted, owing to their capacity to emulate brain activity. In particular, solid-state electrolyte-gated electrodes have garnered significant attention because they enable the simultaneous achievement of outstanding synaptic characteristics and mass productivity by adjusting proton migration. However, the inevitable interface traps restrict the protons at the channel–electrolyte interface, resulting in the deterioration of synaptic characteristics. Herein, we propose a solid-state electrolyte-based artificial synaptic device with magnesium oxide (MgO) to achieve outstanding synaptic characteristics in humanlike mechanisms by reducing the interface trap density via dangling bond passivation. In addition, the feasibility of utilizing MgO as a proton reservoir, capable of supplying protons stably and maintaining the proton–electron coupling effect, is demonstrated. With the proton reservoir layer, a significantly greater number of conductance weight states, as well as long-term plasticity over 200 s, is achieved at a low operating power (250 fJ). Furthermore, a pattern recognition simulation is performed based on the synaptic characteristics of the proposed synaptic device, yielding a high pattern recognition accuracy of 94.03%. These results imply the potential for advancing high-performance neuromorphic computing systems.

Two-dimensional (2D) transition metal dichalcogenides (TMDCs) known for their exceptional electrical and optical properties have emerged as promising channel materials for next-generation electronics. However, as strong Fermi-level pinning (FLP) between the metal and the 2D TMDC material at the source/drain (S/D) contact decides the Schottky barrier height (SBH), the transistor polarity is fixed to a certain type, which remains a challenge for the 2D TMDC field-effect transistors (FETs). Here, a S/D contact structure with a quasi-zero-dimensional (quasi-0D) contact interface, in which the dimensionality reduction effect alleviates FLP, was developed to gain controllability over the polarity of the 2D TMDC FET. As a result, conventional metal contacts on the WSe2FET showed n-type characteristics due to strong FLP (pinning factor of 0.06) near the conduction band, and the proposed quasi-0D contact enabled by the Ag conductive filament on the WSe2FET exhibited p-type characteristics with a SBH very close to the Schottky–Mott rule (pinning factor of 0.95). Furthermore, modeling of Schottky barriers of conventional contacts, one-dimensional (1D) contacts, and quasi-0D contacts revealed that the SBH of the quasi-0D contact is relatively less subject to interface dipoles that induce FLP, owing to more rapid decaying of dipole energy. The proposed contact in this study provided a method that progressed beyond the alleviation of FLP to achieve controllable polarity. Moreover, reducing the contact dimensionality to quasi-0D will enable high compatibility with the further scaled-down nanoscale device contact structure.

Panic disorder is characterized by uncontrollable fear accompanied by somatic symptoms that distinguish it from other anxiety disorders. Neural mechanisms underlying these unique symptoms are not completely understood. Here, we report that the pituitary adenylate cyclase-activating polypeptide (PACAP)-expressing neurons in the lateral parabrachial nucleus projecting to the dorsal raphe are crucial for panic-like behavioral and physiological alterations. These neurons are activated by panicogenic stimuli but inhibited in conditioned fear and anxiogenic conditions. Activating these neurons elicits strong defensive behaviors and rapid cardiorespiratory increase without creating aversive memory, whereas inhibiting them attenuates panic-associated symptoms. Chemogenetic or pharmacological inhibition of downstream PACAP receptor-expressing dorsal raphe neurons abolishes panic-like symptoms. The pontomesencephalic PACAPergic pathway is therefore a likely mediator of panicogenesis, and may be a promising therapeutic target for treating panic disorder.

Negative differential resistance (NDR) based on the band-to-band tunneling (BTBT) mechanism has recently shown great potential in improving the performance of various electronic devices. However, the applicability of conventional BTBT-based NDR devices is restricted by their insufficient performance due to the limitations of the NDR mechanism. In this study, we develop an insulator-to-metal phase transition (IMT)-based NDR device that exploits the abrupt resistive switching of vanadium dioxide (VO2) to achieve a high peak-to-valley current ratio (PVCR) and peak current density (Jpeak) as well as controllable peak and valley voltages (Vpeak/valley). When a phase transition is induced in VO2, the effective voltage bias on the two-dimensional channel is decreased by the reduction in the VO2resistance. Accordingly, the effective voltage adjustment induced by the IMT results in an abrupt NDR. This NDR mechanism based on the abrupt IMT results in a maximum PVCR of 71.1 through its gate voltage and VO2threshold voltage tunability characteristics. Moreover, Vpeak/valleyis easily modulated by controlling the length of VO2. In addition, a maximum Jpeakof 1.6 × 106A/m2is achieved through light-tunable characteristics. The proposed IMT-based NDR device is expected to contribute to the development of various NDR devices for next-generation electronics.

•The OSL MIS contact structure was applied to a-IGZO FETs, resulting in an on-current enhancement.•In-depth analysis elucidated the mechanism of OSL MIS contact, demonstrating how OAD modulation enhances the electrical properties at the a-IGZO contact interface.•The OAD modulated OSL MIS contact structure induces interlayer doping, generation of shallow donors in a-IGZO, and an interface dipole, which together contribute to lowering the Schottky barrier height (SBH).•To confirm the superiority of the OSL MIS contact structure as a source/drain contact in a-IGZO FETs, SBH and contact resistivity values were extracted.

This research was initiated to track the hardening and fracture behaviors of mortar cement utilizing a more convenient and cost-effective method compared to other non-destructive evaluation techniques. In pursuit of this aim, we selected the graphite paper sensor (GPS) to track the hardening and fracture behaviors. The GPS was manufactured using A4-sized paper and 4B grade pencil. Probes were set to copper wire and silver particle adhesive. Adhesive tape was used to protect graphite lines and probes. Optimized condition of GPS was set with different graphite line lengths and drawing times. The optimized condition was set to 10 mm of graphite line length and five times of drawing. As the drawing time increased, the graphite line was cracked and delaminated, while graphite was covered in the broader area. The hardening process was tracked using GPS with different water ratios in the mortar cement mixture. The electrical resistance (ER) behavior of GPS was analyzed during the hardening process, and humidity in mortar cement decreased. We tracked the humidity using GPS in mortar cement, and the optimized condition of the cement mixture ratio can be determined. After the hardening of mortar cement, the mechanical property was evaluated using the splitting tensile test to evaluate the optimized condition of water contents in the cement mixture. We determined The complete hardening of the mortar cement was confirmed when the electrical resistance (ER) of the GPS returned to zero. We suggested that this comprehensive approach facilitated a thorough understanding of the hardening and fracture behaviors of mortar cement, and this data contributed to the development of more efficient and effective tracking techniques in this field.

Titanium Silicide (TiSi2 is a primary contact material with low-resistance contact characteristics used in nanodevices. However, the rapid scaling trend requires further improvement to achieve both high thermal stability and low contact resistivity. Herein, a method for simultaneously improving the contact resistivity and thermal stability of the TiSi2 /Si interface is proposed by inserting a Ta interlayer into Ti/p-Si. The Ta-interlayered TiSi2 (Ta IL TiSi2) achieves an improved contact resistivity by approximately 7.9 times compared to that without the Ta interlayer. This remarkable improvement is due to the smooth contact morphology resulting from the suppressed excess diffusion of Ti and Si and dopant segregation at the TiSi2/Si interface. Particularly, because additional reaction during post annealing is minimized by the Ta interlayer, Ta IL TiSi2 shows a low sheet resistance of $3.71~\Omega /\Box $ even after post annealing at 600 °C & 30 min, which is much lower than the conventional TiSi2 scheme under the same annealing conditions. These results are expected to provide insights into state-of-the-art CMOS-based devices that require both low contact resistivity and better thermal margins.

Given the limitations imposed by the physical properties of silicon semiconductors, various wide-bandgap-based semiconductor materials are being actively developed and utilized. Also, the use of crystalline materials such as diamond has been increasing in recent years. An understanding of crystal quality and the extent of internal defects is becoming increasingly important for the development and application of such crystalline materials. X-ray topography (XRT) nondestructively yields information on crystal surfaces and internal defects. In particular, XRT using synchrotron X-rays quickly provides high-resolution images of defects in single crystals. Here, we confirmed the utility of synchrotron white-beam XRT (SWXRT). We established the technique and used it to evaluate the characteristics of a representative, wide-bandgap-based semiconductor material. The SWXRT installed in the 9D beamline of the Pohang accelerator laboratory has an eight-axis sample stage and three-axis detector motion and thus defects in wafers several inches in size in various XRT measurement modes. The SWXRT device not only accepts analog X-ray film, but also yields large-area panel images and data for high-resolution X-ray cameras. We used high-resolution X-ray film and a digital detector to rapidly acquire and analyze the diffraction image of the SiC substrate, which is a representative single-crystal power semiconductor. We expect the quality and defect information of various monocrystalline materials to increase in the near future.

In this article, we introduce physical-layer security enhancement technique based on artificial noise for secure device-to-device (D2D) communications within a platoon in vehicular platooning networks. In particular, we consider a scenario that two D2D-enabled platoons are on the same way. All the vehicles in one platoon are used to generate artificial noise to enhance the secrecy of D2D communications within the other platoon against information leakage to a potential eavesdropping vehicle. We propose artificial noise generation strategies by the platoon according to the assumption on channel state information (CSI): full-CSI and partial CSI assumptions. We further analyze the effect of artificial noise depending on the relationship between the number of vehicles in two platoons. We finally evaluate the performance of our proposed schemes in terms of secrecy rate through extensive simulations and provide useful intuitions for secure platooning.

The emergence of microfluidic devices and computational fluid dynamics (CFD) has propelled the need for next-generation biomimetic cell culture platforms that are flexible for monitoring and regulation. Therefore, this study evaluated a CFD application in an in silico-designed and spheroid-based flow integration 3D cell culture chip (SFI chip) to illustrate cell culture, drug screening, cytokine delivery, and differentiation of cells in a platform that partially recapitulates the natural environment. Our results show that a flow rate of 0.05 mL h−1or less induced no physical stress in the SFI chip (15 mm), and uniform cell spheroids (approximately 200 μm) were formed across the platform. The cultured cells were tested in several experimental contexts (co-culture, drug screening, cytokine delivery, and differentiation), demonstrating the usefulness of computational simulation in expediting discovery and simple and effective means to scale the production of standardized cell spheroids cultured under dynamic and natural conditions. Advanced cell culture technologies can be used to accelerate research and discovery and the preclinical and clinical development of cell and cell-free therapies for urgent medical needs.

This study was designed to evaluate the effectiveness of a newly developed quality assurance system for electromagnetic field therapy called tumor treating fields therapy, which uses an alternating electric field to treat cancer based on an intermediate frequency of 100–300 kHz. The quality assurance system for electromagnetic field therapy consisted of a water phantom, a probe, and a digital data acquisition (DAQ) board. Low intensity alternating electric fields (200 kHz, 0–.1 V/cm) were created within the water phantom using a function generator and a high voltage amplifier. The electric potential formed inside the water phantom was measured using the probe and DAQ board. The electric field intensity was derived by measuring the electric potential at the 190 points (19 × 10 cm2) of the midplane. Accuracy was evaluated by gamma index analysis, which compared the measured electric field and the simulation result. The mean difference between the simulation result and the measured electric potentials within the water phantom was 0.31 V. The gamma passing rate for the tolerance levels of 0.5 V/5 mm was 95.5% for electric potential comparison showing good agreement between simulation and experimental results. The mean difference between the electric field distribution within the water phantom and the simulated values was 0.09 V/cm and the gamma passing rate for the tolerance levels of (0.2 V/cm)/5 mm was ~ 97.3%. These results confirmed the feasibility of the quality assurance system for electromagnetic field therapy.

ABSTRACTIn order to investigate the impact of social media monitoring on a firm’s market understanding and performance, and how to manage online rumors, two complementary studies are conducted on visitors’ engagement and three aspects of engagement. The first study indicates that conversations and inbound traffic positively affect visitors’ engagement, which, along with referrals, influences social media monitoring’s impact on market understanding. Next, the impact of social media monitoring on a firm’s performance is affected by social media monitoring’s impact on market understanding. The second study indicates that first, online rumors from direct engagement are more likely to be true than those from indirect engagement, second, online rumors’ spreading shows similar engagement patterns, third, a firm’s quick and frank reaction to rumors can reduce their influence, and fourth, adding contents to online rumors increases cognitive engagement, and a company’s support or denial of online rumors affects all engagement dimensions.

This work presents an illustration of Nagra’s AMAC (Advanced Methodology for Activation Characterization) approach to the South Korean pressurized water reactor Kori-1 decommissioning. The results achieved are supported by the existing experience from the detailed AMAC applications to Swiss NPPs and are used not only for a demonstration of the applicability of AMAC to South Korean NPPs, but also for a first approximation of the activated waste volumes to be expected from Kori-1. A packaging concept based on the above activation characterization is also presented, using the AMAC algorithmic optimization software ALGOPACK leading to the minimum number of waste containers needed given the selected packaging constraints. Nagra’s AMAC enables effective planning before and during NPP decommissioning, including recommendations for cutting profiles for diverse reactor components and building structures. Finally, it is expected to lead to significant cost savings by reducing the number of expensive waste containers, by optimizing a potential melting strategy for metallic waste as well as by significantly limiting the number of radiological measurements. All information about Kori-1 used for the purpose of this study was collected from publicly available sources.

IMPORTANCE: There is limited information describing the full spectrum of coronavirus disease 2019 (COVID-19) and the duration of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA detection in children. OBJECTIVE: To analyze the full clinical course and the duration of SARS-CoV-2 RNA detectability in children confirmed with COVID-19 in the Republic of Korea, where rigorous public health interventions have been implemented. DESIGN, SETTING, AND PARTICIPANTS: This case series of children with COVID-19 was conducted in 20 hospitals and 2 nonhospital isolation facilities across the country from February 18, 2020, to March 31, 2020. Children younger than 19 years who had COVID-19 were included. EXPOSURES: Confirmed COVID-19, detected via SARS-CoV-2 RNA in a combined nasopharyngeal and oropharyngeal swab or sputum by real-time reverse transcription–polymerase chain reaction. MAIN OUTCOMES AND MEASURES: Clinical manifestations during the observation period, including the time and duration of symptom occurrence. The duration of SARS-CoV-2 RNA detection was also analyzed. RESULTS: A total of 91 children with COVID-19 were included (median [range] age, 11 [0-18] years; 53 boys [58%]). Twenty children (22%) were asymptomatic during the entire observation period. Among 71 symptomatic cases, 47 children (66%) had unrecognized symptoms before diagnosis, 18 (25%) developed symptoms after diagnosis, and only 6 (9%) were diagnosed at the time of symptom onset. Twenty-two children (24%) had lower respiratory tract infections. The mean (SD) duration of the presence of SARS-CoV-2 RNA in upper respiratory samples was 17.6 (6.7) days. Virus RNA was detected for a mean (SD) of 14.1 (7.7) days in asymptomatic individuals. There was no difference in the duration of virus RNA detection between children with upper respiratory tract infections and lower respiratory tract infections (mean [SD], 18.7 [5.8] days vs 19.9 [5.6] days; P = .54). Fourteen children (15%) were treated with lopinavir-ritonavir and/or hydroxychloroquine. All recovered, without any fatal cases. CONCLUSIONS AND RELEVANCE: In this case series study, inapparent infections in children may have been associated with silent COVID-19 transmission in the community. Heightened surveillance using laboratory screening will allow detection in children with unrecognized SARS-CoV-2 infection.

ABSTRACTThis study was conducted to assess the nasopharyngeal (NP) carriage and acute otitis media (AOM) occurrence in Korean children who received pneumococcal conjugate vaccines (PCVs). The longitudinal study was conducted through four consecutive visits. At each visit, NP aspirates were obtained and subjects were asked to visit if AOM occurred. A total of 305 subjects were enrolled and received PCV13 (n = 182) or PCV10 (n = 123). In the PCV13 group, the NP carriage of Streptococcus pneumoniaeat each visit was 2.7%, 14.8%, 18.7%, and 15.9%, respectively. Non-typeable Haemophilus influenzae(NTHi) was 3.3%, 2.7%, 2.7%, and 5.5%, and that of Moraxella catarrhaliswas 1.1%, 9.3%, 4.9%, and 0.5%. In the PCV10 group, the NP carriage of S. pneumoniaeat each visit was 3.3%, 7.3%, 6.5%, and 4.1%, respectively. That of NTHi was 2.4%, 4.1%, 1.6%, and 0.8%, and that of M. catarrhaliswas 4.1%, 0.8%, 0.8%, and 0.0%. AOM occurrence in the PCV13 group observed after the primary dose and before booster dose was 20.9%, occurrence after booster dose was 11.0%, and the incidence of two or more AOM was 11.0%. In the PCV10 group, AOM occurrence was 9.8%, 7.3%, respectively, and the incidence of two or more AOM was 2.4%. The predominant S. pneumoniaeisolated were non-vaccine type (10A, 15A, and 15B). In this study, AOM occurrence was lower in the PCV10 group than in the PCV13 group. This seems to be related to ecological changes that lead to differences in NP carriage, especially S. pneumoniaeand NTHi.

Despite considerable academical and practical interests on separation of water-in-oil emulsion via special wettable membranes, fundamental understanding on microscale dynamics of water droplets on under-oil-hydrophilic membranes (UOHMs) at early stages during separation is still very preliminary due to temporal and spatial resolution of existing visualization techniques. To this end, we here succeed in a direct microscopic visualization of separation processes of water droplets on the UOHMs by employing a high-speed, two-dimensional synchrotron white-beam X-ray microimaging technique. During the separation of water-in-oil emulsion, microscale dynamic behaviors of water droplets on hydrophilic membrane surfaces immersed in the different oil media (i.e., hexane, kerosene, and light and heavy mineral oils) and oil films between water droplets and membrane surfaces are visualized and analyzed.

Fungi cause serious nosocomial infections including candidiasis and aspergillosis, some of which display reduced susceptibility to current antifungals. Inorganic compounds have been found to be beneficial against various medical ailments but have yet to be applied to fungal infections. Here, we explore the activity of linear and square-planar gold(I)−phosphine complexes against a panel of 28 fungal strains including Candidaspp., Cryptococcusspp., Aspergillusspp., and Fusariumspp. Notably, two square-planar gold(I) complexes with excellent broad-spectrum activity display potent antifungal effects against strains of Candida auris, an emerging multidrug-resistant fungus that presents a serious global health threat. To characterize the biological activity of these gold(I) complexes, we used a series of time–kill studies, cytotoxicity and hemolysis assays, as well as whole-cell uptake and development of resistance studies.

We report experimental results on the microfabrication of three types of folded waveguide circuits with a high aspect ratio by using a high-energy X-ray LIGA technique. A W-band folded waveguide with a total of 80 periods was designed for a traveling-wave-tube (TWT) amplifier operating at 90 GHz–100 GHz. The measured return loss and insertion loss of the W-band fabricated circuit were–10 dB and 0.42 dB/cm, respectively. A G-band circuit showed a higher insertion loss of 1.57 dB/cm. An additional circuit fabrication for a 850-GHz folded waveguide TWT was also successfully carried out. The broad-wall angle measured with respect to the narrow wall of the rectangular waveguide was very close to 90◦, indicating an excellent resolution compared to that of other microfabrication techniques, such as deep reactive ion etching (DRIE) and ultraviolet (UV) lithography, electroplating, and polymer replication (LIGA).

Colloidal arrays show structural colors through wavelength-selective diffraction. The structural colors are dynamically tunable with mechanical deformation for a non-close-packed colloidal array embedded in an elastic matrix. However, such compositions usually render photonic materials transparent and structural color low saturated. In this work, we formulate colloidal inks to produce mechanochromic films and patterns that show consistent structural colors with high saturation. The inks are composed of a high-volume fraction of silica particles and a low fraction of polydopamine nanoparticles dispersed in an elastomer-forming resin. The silica particles have repulsive interparticle potential and form a non-close-packed array, whereas polydopamine nanoparticles are positioned in the interstitial areas. The colloidal arrays are captured in the elastomer by photopolymerization of the resin. As polydopamine nanoparticles reduce incoherent scattering and make the materials opaque, the structural color arisen from the colloidal array is pronounced and independent of the background. Moreover, the photonic materials show a dynamic and reversible change of structural color according to deformation. For large strains, the photonic effect is overwhelmed by absorption of polydopamine nanoparticles, rendering the materials dark brown. This unique mechanochromic property is used to make patterns that are reversibly color-tunable and hidable, which are appealing for user-interactive anti-counterfeiting and active camouflage.

ABSTRACTThere have been significant changes in global energy initiatives following the shale gas developments, predominantly in North America. Due to the over-supply of shale gas, local gas prices are steadily declining in North America. In the case of continuous decreasing prices of gas, it is expected that the increase in the economic efficiency of gas power generation will lead global oil companies to enter the gas power generation sector in developing and under-developed countries possessing gas reserves. Global oil companies co-develop natural gas and electricity concurrently in developing/under-developed countries. Global oil companies now feature electricity generation as a key business area. Global electric utilities respond to global oil companies’ entry into electricity production by cross-enter into gas development. This paper examines recent industrial dynamics that could considerably influence future natural gas and power generation markets due to the co-development strategy of global oil companies and electric utilities. This paper shows the boundary of energy business concerning electricity and gas is blurring.

To increase the efficiency of jumping-droplet condensation, this study proposes a hierarchical superhydrophobic surface that promotes coalescence-induced jumping. Inspired by the phenomenon in which a growing droplet moves spontaneously within a superhydrophobic V structure, we fabricated nanograssed zigzag structures on the surface to induce the spontaneous motion of condensed droplets. The direction of the motion was parallel to the surface, so the condensed droplets easily coalesced on it. Compared with a conventional nanograssed superhydrophobic surface, the proposed surface increased the frequency of coalescence-induced jumping by ≥17 times and increased the cumulative volume of jumping droplets by ∼1.8 times. The proposed surface has great potential to increase the efficiency of applications such as water- and energy-harvesting and cooling systems that exploit jumping-droplet condensation.

ABSTRACTWe assessed the immunogenicity and safety of a three-dose primary vaccination schedule with the combined diphtheria-tetanus-acellular pertussis-inactivated poliovirus/Haemophilus influenzae type b vaccine (DTPa-IPV/Hib) in Korean infants.In this phase III open-label, multicenter study (NCT01309646), healthy infants aged 42–69 days (randomized 1:1) received three doses of either pentavalent DTPa-IPV/Hib (DTPa-IPV/Hib group) or DTPa-IPV and Hib vaccines administered separately (DTPa-IPV+Hib group) at 2, 4, 6 months of age. The primary objective was to demonstrate non-inferiority of DTPa-IPV/Hib compared to DTPa-IPV+Hib vaccines in terms of immune responses to all vaccine antigens, 1 month post-dose 3. Solicited symptoms (local and general) were recorded during 4 days, and unsolicited adverse events (AEs) during 31 days, after each vaccination. Serious AEs (SAEs) were recorded throughout the study duration.The immunogenicity of the pentavalent DTPa-IPV/Hib vaccine was non-inferior compared to concomitant administration of DTPa-IPV+Hib vaccines. One month post-dose 3, nearly all infants had antibody levels above the seroprotective thresholds for anti-diphtheria toxoid, anti-tetanus toxoid, anti-polyribosyl-ribitol phosphate, and anti-poliovirus type 1, 2 and 3, and had antibody levels above the seropositive thresholds for anti-pertussis toxoid (PT), anti-filamentous hemagglutinin (FHA) and anti-pertactin (PRN) antibodies. A vaccine response for PT, FHA and PRN was observed in at least 96.7% of study participants. Anti-PRP geometric mean concentrations appeared lower for the DTPa-IPV/Hib group (8.456 µg/mL) than for the DTPa-IPV+Hib group (18.700 µg/mL). In both groups, the most common solicited symptoms were injection site redness and irritability. Fifty-seven SAEs were reported throughout the study; none were considered to be vaccination related.

Printing structurally colored patterns is of great importance for providing customized graphics for various purposes. Although a direct writing technique has been developed, the use of colloidal dispersions as photonic inks requires delicate printing conditions and restricts the mechanical and optical properties of printed patterns. In this work, we produce elastic photonic microbeads through scalable bulk emulsification and formulate photonic inks containing microbeads for direct writing. To produce the microbeads, a photocurable colloidal dispersion is emulsified into a highly concentrated sucrose solution via vortexing, which results in spherical emulsion droplets with a relatively narrow size distribution. The microbeads are produced by photopolymerization and are then suspended in urethane acrylate resin at volume fractions of 0.35–0.45. The photonic inks retain high color saturation of the microbeads and offer enhanced printability and dimensional control on various target substrates including fabrics, papers, and even skins. Importantly, the printed graphics show high mechanical stability as the elastic microbeads are embedded in the polyurethane matrix. Moreover, the colors show a wide viewing angle and low-angle dependency due to the optical isotropy of individual microbeads and light refraction at the air–matrix interface. We postulate that this versatile direct writing technique is potentially useful for structural color coating and printing on the surfaces of arbitrary 3D objects.

ObjectiveTransmissibility of COVID-19 by children in the household is not clear. Herein, we describe children’s role in household transmission of COVID-19.Design and settingAll paediatric COVID-19 index cases and their household members reported from 20 January to 6 April 2020 in South Korea were reviewed. The secondary attack rate (SAR) from child index case to household secondary case was calculated. Epidemiological and clinical findings of child index case-household secondary case pair was assessed.ResultsA total of 107 paediatric COVID-19 index cases and 248 of their household members were identified. One pair of paediatric index-secondary household case was identified, giving a household SAR of 0.5% (95% CI 0.0% to 2.6%). The index case was self-quarantined at home after international travel, stayed in her room, but shared a meal table with the secondary case.ConclusionThe SAR from children to household members was low in the setting of social distancing, underscoring the importance of rigorous contact tracing and early isolation in limiting transmission within households.

A monolayer Ca2Nb3O10(CNO) nanosheet was deposited on a Pt/Ti/SiO2/Si substrate using the Langmuir–Blodgett method. This monolayer CNO nanosheet with a (001) surface termination was used as a seed layer to reduce the growth temperature of the crystalline (Na1–xKx)NbO3(NKN) film. The crystalline NKN film was preferentially grown along the [001] direction at 400 °C. The ferroelectric and piezoelectric properties of this NKN film were influenced by the postannealing atmosphere due to the variations in the amounts of oxygen vacancies in the NKN film. The crystalline NKN film annealed at 300 °C under 50 Torr O2atmosphere showed promising ferroelectric and piezoelectric properties; εrof 303 and tan δ of 2.0% at 100 kHz, Psof 15.3 μC/cm2, Prof 11.7 μC/cm2, and Ecof 78 kV/cm, and d33of 139 pm/V. This NKN film showed the lowest leakage current, which can be explained by the Schottky emission mechanism. The Schottky barrier heights of the Pt/NKN and NKN/CNO/Pt interfaces were calculated to be 0.97 and 0.28 eV, respectively. The results of this work suggest a new method to grow crystalline thin films at low temperatures by using metal-oxide nanosheets as the seed layer.

The objective of this study was to determine the effect of ionizing radiation (IR) exposure of parents on carcinogenesis of the next generation focusing on the epigenetic perspective to clarify the relationship between radiation dose and carcinogenesis in F1 generation SD rats. F1 generations from pregnant rats (F0) who were exposed to gamma rays were divided into three groups according to the dose of radiation: 10 rad, 30 rad, and untreated. They were intraperitoneally injected with 50 mg/kg of diethylnitrosamine (DEN). Carcinogenesis was analyzed by examining expression levels of tumor suppressor genes (TSG) and other related genes by methylation-specific polymerase chain reaction (MSP). DNA methylation in liver tissues was evaluated to discern epigenetic regulation of transgenerational carcinogenesis vulnerability following IR exposure. Numerous studies have proved that transcriptional inactivation due to hypermethylation of TSG preceded carcinogenesis. Results of this study revealed hypermethylation of tumor suppressor gene SOCS1 in group treated with 30 rad. In addition, genes related to DNA damage response pathway (GSTP1, ATM, DGKA, PARP1, and SIRT6) were epigenetically inactivated in all DEN treated groups. In the case of proto-oncogene c-Myc, DNA hypermethylation was identified in the group with low dose of IR (10 rad). Results of this study indicated that each TSG had different radiation threshold level (dose-independent way) and DEN treatment could affect DNA methylation profile irrelevant of ionizing radiation dose.

A new radiation scale is proposed. With empathy toward the vast majority of people who are not well versed in radiation and related matters, and thus suffering from misunderstanding that breeds unnecessary fear of radiation, the aim of proposing a new radiation scale, radiation index(RAIN), is to put the general public at ease with the concept of radiation. RAIN is defined in dimensionless numbers that relate any specific radiation dose to a properly defined reference level. As RAIN is expressed in plain numbers without an attached scientific unit, the public will feel comfortable with its friendly look, which in turn should help them understand radiation dose levels easily and allay their anxieties about radiation. The expanded awareness and proper understanding of radiation will empower the public to feel that they are not hopeless victims of radiation. The correspondence between RAIN and the specific accumulated dose is established. The equivalence will allow RAIN to serve as a common language of communication for the general public with which they can converse with radiation experts to discuss matters related to radiation safety, radiation diagnosis and therapy, nuclear accidents, and other related matters. Such fruitful dialogues will ultimately enhance public acceptance of radiation and associated technologies.

A new reduced-dose tetanus–diphtheria (Td) vaccine was developed in Korea, and phase I and II clinical trials were successfully undertaken. We conducted this double-blind, randomized, multicenter phase III clinical trial to assess the immunogenicity and safety of the new Td vaccine.

This study evaluated the productivity on the market of olive flounder, Paralichthys olivaceus, raised in biofloc. The marketability evaluation was measured by morphology, body composition, hematological parameters, and sensory evaluation in P. olivaceus(biofloc fish; mean weight 1142 ± 260 g, mean length 43.40 ± 2.9 cm, and control fish; mean weight 1121 ± 173 g, mean length 44.60 ± 1.8 cm) raised in biofloc for 8 months. Morphologically, P. olivaceusraised in biofloc showed a significant decrease in head depth and head depth-head length ratio (P < 0.05). Hematological parameters (hematocrit and hemoglobin) and plasma components (calcium, magnesium, glucose, cholesterol, and alanine aminotransferase) were not significantly different between P. olivaceusraised in the biofloc and the control. No significant differences were discovered in the proximate composition (moisture, crude protein, crude fat, crude fiber, and ash) of P. olivaceusraised in the biofloc compared with the control group. In amino acid composition, valine and isoleucine in P. olivaceusraised in biofloc were significantly higher than in the control group (P < 0.05). The saturated fatty acids (capric acid and palmitic acid) in P. olivaceusraised in the biofloc were significantly increased (P < 0.05). The unsaturated fatty acids (linoleic acid and dihomo-γ-linoleic acid) in P. olivaceusraised in the biofloc were significantly decreased (P < 0.05); however, docosahexaenoic acid was significantly increased (P < 0.05). No significant differences were noted in other sensory evaluations, including fishy odor, chewiness, moisture, viscosity, elasticity, hardness, meaty gloss, meat-colored transparency, smell, flavor, texture, and appearance. However, the comprehensive preference of P. olivaceusraised in biofloc was significantly increased (P < 0.05). This study showed that fish products of P. olivaceusraised in a biofloc system had approximately the same nutritional value as commercial fish products of P. olivaceus, suggesting a marketability potential as food.

ABSTRACTIn 2005, a single-dose varicella vaccination was incorporated into the national immunization program in Korea. Although the Oka strain is the most commonly circulating Varicella zoster virus (VZV) genotype in Korea, a domestically manufactured vaccine based on the MAV strain is widely distributed in Korea. High vaccination coverage was achieved, but breakthrough infections were frequently reported. Therefore, in this study, we aimed to analyze the maintenance of immunity after single-dose vaccination and to compare the immunity provided by the MAV and Oka vaccines. Enzyme-linked immunosorbent assays of samples from 715 vaccinated Korean children were used to assess seropositivity rates against VZV. Additionally, fluorescent-antibody-to-membrane-antigen (FAMA) tests were performed in 35 individuals in the MAV vaccine group, and seropositivity rates against the Oka strain were determined. The progressive decrease of the seropositivity rate was demonstrated from ages 1 to 4 as follows: 65% in age 1, 59% in age 2, 53% in age 3, 49% in age 4. It then increased to 62% in age 5 and 70% in age 6. Both the MAV and Oka vaccine groups showed a progressive decrease of the seropositivity rate from the age of 1 to 4 years, but the MAV vaccine group had higher seropositivity rates. In FAMA test, the MAV group demonstrated 71% seropositivity against the Oka strain. This study indicates that immunity wanes after single-dose varicella vaccination and that the MAV vaccine is not inferior to the Oka vaccine in providing immunity against VZV. The MAV vaccine also induced cross-immunity against circulating Oka strain.

ABSTRACTNaegleria fowleri, known as the brain-eating amoeba, causes acute primary amoebic meningoencephalitis. During swimming and other recreational water activities, N. fowleritrophozoites penetrate the nasal mucosa and invade the olfactory bulbs, resulting in intense inflammatory reactions in the forebrain tissue. To investigate what kinds of inflammasome molecules are expressed in target cells due to N. fowleriinfection, human macrophage cells (THP-1 cells) were cocultured with N. fowleritrophozoites in a noncontact system, and consequently, interleukin-1β (IL-1β) production was estimated. Caspase-1 activation and IL-1β production from THP-1 cells by Western blotting and the culture supernatant by enzyme-linked immunosorbent assay analysis were observed at 3 h after cocultivation. In addition, the increased expression of ASC and NLRP3, which make up an inflammasome complex, was also observed at 3 h after cocultivation. To confirm the caspase-1 activation and IL-1β production via the NLRP3 inflammasome in THP-1 cells triggered by N. fowleritrophozoites, THP-1 cells were pretreated with several inhibitors. The inhibition assay showed that CA-074 (a cathepsin B inhibitor), glybenclamide (an NLRP3 molecule inhibitor), and N-benzyloxycarbony-Val-Ala-Asp(O-methyl)-fluoromethylketone (Z-VAD-FMK; a caspase-1 inhibitor) reduced the levels of caspase-1 activation and IL-1β production from THP-1 cells. This study suggests that N. fowleriinfection induces the NLRP3 inflammasome, which activates caspase-1 and subsequently produces IL-1β, thus resulting in inflammation.

Although previous studies suggest that nanotopographical features influence properties and behaviors of stem cells, only a few studies have attempted to derive clinically useful somatic cells from human pluripotent stem cells using nanopatterned surfaces. In the present study, we report that polystyrene nanopore-patterned surfaces significantly promote the pancreatic differentiation of human embryonic and induced pluripotent stem cells. We compared different diameters of nanopores and showed that 200 nm nanopore-patterned surfaces highly upregulated the expression of PDX1, a critical transcription factor for pancreatic development, leading to an approximately 3-fold increase in the percentage of differentiating PDX1+pancreatic progenitors compared with control flat surfaces. Furthermore, in the presence of biochemical factors, 200 nm nanopore-patterned surfaces profoundly enhanced the derivation of pancreatic endocrine cells producing insulin, glucagon, or somatostatin. We also demonstrate that nanopore-patterned surface-induced upregulation of PDX1 is associated with downregulation of TAZ, suggesting the potential role of TAZ in nanopore-patterned surface-mediated mechanotransduction. Our study suggests that appropriate cytokine treatments combined with nanotopographical stimulation could be a powerful tool for deriving a high purity of desired cells from human pluripotent stem cells.

We report a measurement of the effective refractive index of a nematic liquid crystal (NLC) inside a Fabry-Perot (FP) etalon according to the applied electric fields. The effective refractive index of the NLC depends on the intensity of the applied electric field. A wavelength-swept laser with a polygon-scanner-based wavelength filter is used as a wide-band optical source to measure the effective refractive index of the NLC. The bandwidth of the optical source is greater than 90 nm around 1300 nm. The fabricated NLC FP etalon consists of glass substrates, gold layers as the electrodes with highly reflective surfaces, polyimide layers as the planar alignment layers, and an LC layer. Furthermore, we measured the Freedericksz transition voltages for three types of NLC FP etalons having thicknesses of $30.6{\mu}m$, $55.4{\mu}m$, and $108.8{\mu}m$. The Freedericksz transition voltages in the three cases are nearly equal. The measured effective refractive indices in the three cases decreased from 1.67 to 1.51 as the applied electric field intensity was increased. Beyond the threshold electric field, the effective refractive indices quickly decreased and eventually saturated at a value of 1.51 for all cases.

A multicenter, double-blind, randomized, active-control phase III clinical trial was performed to assess the immunogenicity and safety of a trivalent, inactivated split influenza vaccine. Korean children between the ages of 6 months and 18 y were enrolled and randomized into a study (study vaccine) or a control vaccine group (commercially available trivalent, inactivated split influenza vaccine) in a 5:1 ratio. Antibody responses were determined using hemagglutination inhibition assay, and post-vaccination immunogenicity was assessed based on seroconversion and seroprotection rates. For safety assessment, solicited local and systemic adverse events up to 28 d after vaccination and unsolicited adverse events up to 6 months after vaccination were evaluated. Immunogenicity was assessed in 337 and 68 children of the study and control groups. In the study vaccine group, seroconversion rates against influenza A/H1N1, A/H3N2, and B strains were 62.0% (95% CI: 56.8–67.2), 53.4% (95% CI: 48.1–58.7), and 54.9% (95% CI: 48.1–60.2), respectively. The corresponding seroprotection rates were 95.0% (95% CI: 92.6–97.3), 93.8% (95% CI: 91.2–96.4), and 95.3% (95% CI: 93.0–97.5). The lower 95% CI limits of the seroconversion and seroprotection rates were over 40% and 70%, respectively, against all strains. Seroconversion and seroprotection rates were not significantly different between the study and control vaccine groups. Furthermore, the frequencies of adverse events were not significantly different between the 2 vaccine groups, and no serious vaccination-related adverse events were noted. In conclusion, the study vaccine exhibited substantial immunogenicity and safety in Korean children and is expected to be clinically effective.

Sustainability is essential for magneto-mechano-electric (MME) energy harvesters that convert low-frequency magnetic noise into useful electrical energy to be considered a practical power source for implementing real-life Internet of Things (IoT) sensor networks. In this study, we propose a vertically installed MME energy harvester based on a piezoelectric lead magnesium niobate-lead zirconate titanate (Pb(Mn1/3Nb2/3)O3-Pb(Zr,Ti)O3, PMN-PZT) single-crystal macro fiber composite cantilever. The MME harvester generates 12.2 mW output power from a low-amplitude stray magnetic field of 2.5 Oe and exhibits a long-term usable lifetime of 2.5 ×109cycles while maintaining over 90 % of its output. An accelerated life test method is employed to predict the usable lifetime of the MME harvester using an inverse power law-Weibull model with accelerating stress of magneto-mechanical vibration-induced strain. In addition, a standalone wireless environmental monitoring system is demonstrated to operate for 10 weeks by exploiting the harvested power from stray magnetic fields (~2.2 Oe) near the power cables of home appliances. This study paves the way for lifetime assessment and prediction of sustainable MME harvesters to increase the practicability of self-powered IoT devices in smart infrastructures.

A new live attenuated Japanese encephalitis chimeric virus vaccine (JE-CV) has been developed based on innovative technology to give protection against JE with an improved immunogenicity and safety profile. In this phase 3, observer-blind study, 274 children aged 12−24 months were randomized 1:1 to receive one dose of JE-CV (Group JE-CV) or the SA14–14–2 vaccine currently used to vaccinate against JE in the Republic of Korea (Group SA14–14–2). JE neutralizing antibody titers were assessed using PRNT50before and 28 days after vaccination. The primary endpoint of non-inferiority of seroconversion rates on D28 was demonstrated in the Per Protocol analysis set as the difference between Group JE-CV and Group SA14–14–2 was 0.9 percentage points (95% confidence interval [CI]: −2.35; 4.68), which was above the required −10%. Seroconversion and seroprotection rates 28 days after administration of a single vaccine dose were 100% in Group JE-CV and 99.1% in Group SA14–14–2; all children except one (Group SA14–14–2) were seroprotected. Geometric mean titers (GMTs) increased in both groups from D0 to D28; GM of titer ratios were slightly higher in Group JE-CV (182 [95% CI: 131; 251]) than Group SA14–14–2 (116 [95% CI: 85.5, 157]). A single dose of JE-CV was well tolerated and no safety concerns were identified. In conclusion, a single dose of JE-CV or SA14–14–2 vaccine elicited a comparable immune response with a good safety profile. Results obtained in healthy Korean children aged 12−24 months vaccinated with JE-CV are consistent with those obtained in previous studies conducted with JE-CV in toddlers.