Search

During the COVID-19 pandemic, the patterns of visiting commercial areas have changed due to numerous factors, including the risk of infection and the government's state of emergency. This study investigated human mobility changes in commercial areas of 21 cities in Japan by applying time-series clustering of mobile big data during the COVID-19 pandemic. First, the analysis revealed that the human mobility changes were found to be area-specific and were classified into five patterns according to population change captured by mobile data: decreased cluster, slightly decreased cluster, no change cluster, slightly increased cluster, and increased cluster. There were some commercial areas, which were visited by more people, compared with the pre-COVID-19 period. Second, the increased clusters revealed a high proportion of commercial facilities that provide essential services. This finding suggests that the local-scale commercial areas were essential for supporting everyday life during the COVID-19 pandemic. Third, human mobility in commercial areas was temporarily altered, but ultimately returned to the pre-COVID-19 level. Overall, the proposed method and results provide basic information for resilient urban structures in Japan. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess changes in bone mineral density (BMD) and cadmium (Cd) levels in blood and urine in individuals living in a Cd-contaminated area according to the type of osteoporosis medication over a three-year period. This follow-up study included 204 residents living in the vicinity of a closed copper refinery, who had been found to have elevated urinary or blood Cd levels. Cd levels in the blood and urine, as well as BMD, were measured every 6 months. After the first BMD measurement, individuals were prescribed antiresorptives such as alendronate or vitamin D and calcium, according to their BMD. Subjects were classified according to the type of medicine provided over the previous 6 months. General linear models controlling for other factors were used to evaluate the effects of each type of medication on the participants' Cd levels and BMD. Spinal BMD showed a significant increase in the antiresorptive group compared to the nontreatment group. Significant decreases in blood Cd levels were found in the vitamin D and calcium group, in comparison to the nontreatment group, as well as a marginally significant decrease in the antiresorptive group. The vitamin D and calcium group showed a significantly greater decrease in urinary Cd levels than the nontreatment group. In contrast, antiresorptive medication was found to have a negative effect on urinary Cd excretion. These results suggest that vitamin D and calcium treatment for osteoporosis lowers blood Cd levels more effectively and improves urinary Cd excretion. [ABSTRACT FROM AUTHOR]

Arsenic (As) is widely distributed in the environment, and humans can be exposed to As from various sources such as air, water, soil, and food. This study was performed to evaluate the As exposure levels in Korean adults by measuring total As in urine and its relation with the consumption of seafood, a favorite food in Korea. A total of 2077 adults were the study subjects; they ranged in age from 19 to 83, and they were recruited by probability sampling stratified by area, sex, and age. None of the subjects had been exposed to As occupationally. We collected information about the demographic characteristics, lifestyles, and food consumption of study subjects using a questionnaire and followed urine sampling. Diet was assessed in individual interviews using the 24-h recall method. Total As in urine was analyzed using inductively coupled plasma mass spectrometry (PerkinElmer NEXION 300S; Concord, Ontario, Canada). The geometric mean concentration of total As in urine was observed to be 97.6 μg/L and was higher in males (103.9 μg/L) than in females (93.0 μg/L). Total As levels in urine were affected by sex, age, seafood intake, and geographic location. In this study, total As in urine was positively correlated with fish and shellfish consumption, and was mainly determined by As intake through fish and shellfish/grains/flavors. These findings suggest that seafood consumption might be a major contributor to urinary As levels in Korean adults. [ABSTRACT FROM AUTHOR]

The Six Sigma principle is a set of techniques and tools for measuring the defect rate in a process. It seeks to improve the quality of process outputs by identifying and removing the causes of defects. It has a significant advantage in quality improvement and can evaluate the process capability and statistical quality control. Since it was introduced in the 1980s, it has spread to almost all industries. However, it was not effective in the construction industry, where it was completed onsite by personnel rather than in a factory by machines. Therefore, few studies have been conducted on its application in the construction industry. This study was conducted to control slab cracks in the framework in the construction stage through the application of the Six Sigma principle. Using the Define-Measure-Analyze-Improve-Control (DMAIC) methodology, the study was conducted after the 'Critical To Quality' (CTQ) was defined to improve the accuracy of the slab rebar arrangement. The Big Ys from the CTQ were defined as the covering depth deviation (Y1) and the rebar spacing deviation (Y2). In four sample projects, five potential causes of the Y1 and Y2 were identified in four areas, and corresponding improvement and validation methods were proposed. Then six solutions were abstracted, and their corresponding manual, checklist, and slab control plan were prepared. The validation was carried out through two projects, both with high achievements, with the application of the Six Sigma principle. The authors believe this paper offers valuable insights on how the Six Sigma principle can be effectively applied to the construction industry. [ABSTRACT FROM AUTHOR]

LaCoO fibers were synthesized through the calcination of an electrospun polymer-metal precursor fiber. The electrochemical performance of these fibers for oxygen reduction and evolution reactions was characterized in a KOH solution. Additionally, the electrochemical properties were compared with those of a conventional PtRu/C catalyst and a LaCoO powder, which was synthesized using the Pechini method. The LaCoO fibers had a greater surface area compared with the powder, whereas the crystal structures of the fibers and powder were notably similar. The LaCoO fibers demonstrated better electrochemical properties compared with the LaCoO powder, which was attributed to the increased surface area and number of active sites in the fibers. [ABSTRACT FROM AUTHOR]

Four transition metals, namely cobalt, iron, manganese, and nickel, were separately combined with lanthanum metal to synthesize LaMO (M = Co, Fe, Mn, and Ni) perovskites using a sol-gel method. Electrodes for zinc-air rechargeable batteries were prepared with these perovskites and evaluated in terms of their morphology, crystal structure, electric conductivity, surface area, and particle size distribution. The electrochemical properties of the perovskites were characterized as catalysts of bifunctional electrodes for Hgen reduction reaction and oxygen evolution reaction in alkaline solution. Additionally, partially substituted LaNi(M1, M2, or M3)O ( x = 0.25 or 0.5, and M1, 2, 3 = Co, Fe, Mn) perovskites were synthesized to evaluate the effect of partial substitution of a metal in the Ni site, and improved physical and electrochemical properties were obtained. [ABSTRACT FROM AUTHOR]

A study of printed cross‐dipole antenna with slow‐wave parasitic elements used to achieve high efficiency and directivity is presented. The proposed antenna is designed to operate at WLAN channels (5.15–5.85 GHz), and can produce dual‐orthogonal polarisation through a crossed structure. The printed slow‐wave elements play a role that concentrates on travelling wave and delays propagation of electromagnetic wave. Measurement results of this antenna show that it has high gain, low side‐lobe level and wide bandwidth. This proposed design has advantages in terms of manufacturing the antenna easily and optimising the radiation characteristics. [ABSTRACT FROM AUTHOR]

This study was aimed to evaluate whether renal tubular function is impaired by exposure to relatively low concentrations of arsenic. Mean urinary arsenic concentrations and N-acetyl-β-d-glucosaminidase (NAG) activities were compared among 365 and 502 Korean men and women, respectively, in relation to gender, smoking, alcohol consumption, and recent seafood consumption. The study subjects were divided into 4 groups according to urinary NAG activity and seafood consumption prior to urine sampling, and the correlation between arsenic concentration and urinary NAG activity was tested for each group. The mean urinary arsenic level was higher in women, non-smokers, and non-drinkers in comparison to men, smokers, and drinkers, respectively. Individuals who consumed seafood within 3 days prior to urine sampling showed a higher mean urinary arsenic level than those who did not. The correlation between urinary arsenic concentration and NAG activity in urine was significant only in subjects who did not consume seafood within 3 days prior to urine sampling and whose urinary NAG activity was 7.44 U/g creatinine (75th percentile) or higher. The urinary arsenic concentration was a significant determinant of urinary NAG activity in subjects with NAG activity higher than 7.44 U/g creatinine and especially in those who had not consumed seafood recently. These facts suggest that a relatively low-level exposure to inorganic arsenic produces renal tubular damage in humans. [ABSTRACT FROM AUTHOR]

In this paper, we present a cylindrical shaped-reflector antenna which is spatially fed by an off-set linear feed array to form complex beam patterns. The linear feed array consists of twelve microstrip patch elements and forms a flat-topped beam pattern with a beam-width of ±45° in the azimuth plane. The vertical curve on the cylindrical reflector with the linear feed array is shaped to form a cosecant beam pattern within the range of -5° to -25° in the elevation plane. By using the proposed design procedure to form complex beam patterns, a hybrid antenna with a cylindrical reflector aperture of 140 cm x 50 cm is designed to be operated within the IMT 2000 service band, and a prototype antenna is also fabricated. Its electrical performance is measured and compared with simulation results. [ABSTRACT FROM AUTHOR]

Background and objective: CYP2C19 is clinically important in Korea because of the relatively high incidence of poor metabolizers in the population. To fully understand the genetic mechanism of the CYP2C19 defect in poor metabolizers, all variants need to be studied simultaneously. The aim of this study was to investigate the usefulness of CYP2C19 haplotypes as a marker of CYP2C19 enzyme activity in Koreans. Methods: We analysed the single nucleotide polymorphisms and haplotypes of the CYP2C19 gene in 150 healthy Koreans and found three major (frequency > 0·1) haplotypes (H1, H2 and H3). One oral dose of 40 mg omeprazole (Losec®) was administered to 30 subjects grouped as H1/H1, H2/H2, H1/H2, H1/H3 and H2/H3. The pharmacokinetics of omeprazole and its metabolites, 5-hydroxyomeprazole and omeprazole sulphone, in those groups was analysed. Results and discussion: The area under the plasma concentration–time curve (AUC0→∞) and elimination half-life ( T1/2) of omeprazole were significantly greater in the H2/H2 and H2/H3 groups than in the H1/H1 group ( P < 0·05), whereas the metabolic ratios of omeprazole to 5-hydroxyomeprazole were also markedly higher. Conclusion: Although a specific SNP of CYP2C19 may be predictive of enzyme activity, haplotyping is more reliable for identifying poor metabolizers in populations with variant alleles other than CYP2C19*2 and *3 alleles. [ABSTRACT FROM AUTHOR]

Aluminium foams were produced by applying powder metallurgy technology. The process began by making aluminium powder and mixing it with alloy powder (Al5Si4Cu4Mg) and foaming agent (TiH[sub 2]). The mix was compacted to the form of a billet by cold pressing and then it was hot extruded to a dense foamable strip, which was cold rolled to give 40% thickness reduction. The resulting precursor composites of both the extruded strip and the extruded plus rolled strip were then freely foamed without a mould at a constant temperature of 700°C for different foaming times. The effects of aluminium powder content and cold rolling on the foaming characteristics of the foamable composite strip were studied. It is noted that aluminium powder fibre in the extruded composite strip acts as a barrier to pore initiation and evolution due to the higher melting point of pure aluminium fibre than that of the alloy matrix. Cold rolling promotes foaming of the composite strip due to the TiH[sub 2] cracking and debonding between TiH[sub 2] particles and metal matrix. The morphological and microstructural evolution of composite foams was also investigated. The foaming mechanism can be described by the following sequence: cracklike pore nucleation between elongated powder fibres; ellipsoidal, spherical, and polygonal pore growth; and the collapse of pores as a result of coalescence. [ABSTRACT FROM AUTHOR]

The microstructure and mechanical properties of rapidly solidified Al-18 wt% Si and Al-18 wt% Si-5 wt% Fe alloys were investigated by a combination of optical microscopy, scanning electron microscopy, transmission electron microscopy, x-ray diffraction, tensile testing, and wear testing. The centrifugally atomized binary alloy powder consisted of the α-Al (slightly supersaturated with Si) and Si phases and the ternary alloy powder consisted of the α-Al (slightly supersaturated with Si), silicon, and needle-like metastable Al-Fe-Si intermetallic phases. During extrusion the metastable δ-AlFeSi phase in the as-solidified ternary alloy transformed to the equilibrium β-AlFeSi phase. The tensile strength of both the binary and the ternary alloys decreased with a high-temperature exposure, but a significant fraction of the strength was retained up to 573 K. The specific wear gradually increased with increasing sliding speed but decreased with the addition of 5 wt% Fe to the Al-18 wt% Si alloy. The wear resistance improved with annealing due to coarsening of the silicon particles. [ABSTRACT FROM AUTHOR]

A horn antenna having dual-band and dual-polarisation operation is proposed. To implement a small-sized structure providing circular polarisations in the Ka- and K-band, the antenna is designed using the horn radiator on the basis of a conical helix which is exited by two ports for TX and RX in both ends. Through a design optimisation process, a compact dual-band and dual-polarised horn antenna having high gain and high isolation performance was realised. [ABSTRACT FROM AUTHOR]

A study of printed cross-dipole antenna with slow-wave parasitic elements used to achieve high efficiency and directivity is presented. The proposed antenna is designed to operate at WLAN channels (5.15-5.85 GHz), and can produce dual-orthogonal polarisation through a crossed structure. The printed slow-wave elements play a role that concentrates on travelling wave and delays propagation of electromagnetic wave. Measurement results of this antenna show that it has high gain, low side-lobe level and wide bandwidth. This proposed design has advantages in terms of manufacturing the antenna easily and optimising the radiation characteristics. [ABSTRACT FROM AUTHOR]

A hybrid structure consisting of a printed cross dipole and annular ring antennas with a pattern and polarisation diversity for a four‐channel multiple input multiple output system operating in a wireless local area network (LAN) (2.34–2.54 GHz) is presented. The entire antenna size is only 88 × 88 × 44 mm. The envelope correlation coefficient and mean effective gain are computed using measured far‐field radiation patterns. The measured − 10 dB impedance frequency bandwidths of the proposed antenna cover the whole operation bandwidths of wireless LAN with an isolation of less than − 15 dB. [ABSTRACT FROM AUTHOR]

Proposed is a novel way of inserting a propagation stop frequency band for dual-band operation of a leaky wave antenna (LWA). To make the LWA resonate at two frequencies, the stopband is introduced into an existing passband, which induces two specific conditions giving maximum radiation towards a boresight direction at the resonant frequencies locating on both sides of the stopband edge. All experiment results show good agreement with theoretical predictions, which proves the validity and effectiveness of the approaches. [ABSTRACT FROM AUTHOR]

Presented are tunable electrically small antennas composed of split ring resonators (SRRs), which are used to reduce antenna size. To control the resonance frequency, a lumped inductor is inserted between the SRRs and the ground. The proposed antenna operates within Korean personal communication services (PCS) frequency bands of 1750-1870 MHz, and the size of the antenna is 1/33λ0×1/33λ0 with an operating frequency of 1800 MHz. In spite of its small size, the radiation efficiency and -10 dB bandwidth were measured as 82% and 2.4%, respectively. Good agreement between the predicted and measured results ensures the validity of the design method to provide a frequency adjustment using lumped inductors in small SRR antennas. [ABSTRACT FROM AUTHOR]

Synopsis Crinum asiaticum Linne var. japonicum has long been used as a rheumatic remedy, as an anti-pyretic and as an anti-ulcer treatment, and for the alleviation of local pain and fever in Korea and Malaysia. In order to investigate the possibility of Crinum asiaticum Linne var. japonicum extract as a cosmetic ingredient, we measured its anti-inflammatory effect by its inhibition of iNOS (inducible nitric oxide synthase) and the release of PGE2, IL-6, and IL-8. We also measured its anti-allergic effect by its inhibition of beta-hexosamidase release. An HPLC experiment after extraction with 95% EtOH at pH 3.5 showed that Crinum asiaticum Linne var. japonicum was mainly composed of lycorine (up to 1%), a well-known immunosuppressor. The content of lycorine varied, depending on the type of plant tissue analysed and the extraction method. In an anti-inflammatory assay for inhibition of nitric oxide formation on lipopolysaccharide (LPS)-activated mouse macrophage RAW 264.7 cells, the ethanol extract of Crinum asiaticum showed an inhibitory activity of NO production in a dose-dependent manner (IC50 = 58.5 μg ml-1). Additional study by RT-PCR demonstrated that the extract of Crinum asiaticum significantly suppressed the expression of the iNOS gene. Moreover, the extract of Crinum asiaticum did not show any cytotoxicity, but did show a cell proliferation effect against LPS (a 10–60% increase in cell viability). In an assay to determine inhibition of the H2O2-activated release of PGE2, IL-6, and IL-8 in human normal fibroblast cell lines, the release of PGE2 and IL-6 was almost completely inhibited above concentrations of 0.05% and 1%, respectively. Moreover, the release of IL-8 was completely inhibited over the entire range of concentration (> 0.0025%). In order to investigate the skin-sensitizing potentials of the extract of Crinum asiaticum, a human clinical test was performed after repeated epicutaneous 48-h applicaticons under an occlusive patch (RIPT). The repeated and single cutaneous applications of Crinum asiaticum Linne var. japonicum extract under the occlusive patch did not provoke any cumulative irritation and sensitization reactions. The result showed that the extract of Crinum asiaticum Linne var. japonicum has a sufficient anti-inflammatory effect. Therefore, Crinum asiaticum Linne var. japonicum extract may be useful for development as an ingredient in cosmetic products. [ABSTRACT FROM AUTHOR]

Dual roles of calsequestrin (CSQ-1) being the Ca2+ donor and Ca2+ acceptor make it an excellent Ca2+-buffering protein within the sarcoplasmic reticulum (SR). We have isolated and characterized a calsequestrin (csq-1)-null mutant in Caenorhabditis elegans. To our surprise, this mutant csq-1(jh109) showed no gross defects in muscle development or function but, however, is highly sensitive to perturbation of Ca2+ homeostasis. By taking advantage of the viable null mutant, we investigated the domains of CSQ-1 that are important for polymerization and cellular localization, and required for its correct buffering functions. In transgenic animals rescued with various CSQ-1 constructs, the in vivo patterns of polymerization and localization of several mutated calsequestrins were observed to correlate with the structure-function relationship. Our results suggest that polymerization of CSQ-1 is essential but not sufficient for correct cellular localization and function of CSQ-1. In addition, direct interaction between CSQ-1 and the ryanodine receptor (RyR) was found for the first time, suggesting that the cellular localization of CSQ-1 in C. elegans is indeed modulated by RyR through a physical interaction. [ABSTRACT FROM AUTHOR]