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Recently, ferroelectric memory utilizing hafnium oxide has emerged as an attractive option compared to existing memory technologies, primarily due to its scalability and energy-efficient advantages. Among them, hafnium zirconium oxide (HZO) is examined for its short-term memory characteristics to achieve a reservoir computing system known to exhibit remarkable polarization properties, being able to switch between distinct polarization states under the influence of an electric field. These unique properties are of utmost importance in ferroelectric memory applications, where they play a pivotal role in the storage and retrieval of binary data. In this study, we identify and experiment with the electrical characteristics of a ferroelectric tunnel junction (FTJ) device with a metal-ferroelectric-semiconductor (MFS) structure using TiN as the top electrode and HZO as the ferroelectric layer. Moreover, we assess the performance of the device by evaluating its maximum 2 P r (remnant polarization) and tunneling electro resistance (TER) values in different conditions of cell area. Furthermore, we analyze and show short-term memory (STM) characteristics and synaptic properties with 5 cycles of potentiation and depression under conditions of stable dynamic range by coordinating identical and incremental pulses. In the case of incremental pulses (>95 %), the MNIST pattern recognition accuracy is higher than in the case of identical pulses (>94 %). Through a sequence of procedures, the synaptic characteristics of FTJs are confirmed to assess their suitability for use as an artificial synaptic device. [ABSTRACT FROM AUTHOR]

Herein, a hybrid support of Nb-doped TiO 2 and carbon nanotubes (Nb x TO@CNT, x = Nb wt%) was successfully prepared by a facile hydrothermal method. Controlling the annealing temperature to form either anatase (ANb x TO@CNT) or rutile (RNb x TO@CNT) changed the effect of the Nb dopant in the TiO 2 structure. The Pt/RNb 10 TO@CNT electrocatalyst exhibits excellent oxygen reduction reaction activity and durability (E onset : 0.945 V vs. RHE; E 1/2 : 0.888 V vs. RHE; j L : −6.260 mA cm−2). Theoretical calculations predicted that the synergetic effect of Pt/RNb 10 TO@CNT improves the electrochemical performance. The strong metal-support interaction (SMSI) effect and the formation of oxygen vacancies due to the increased amount of Ti3+ was observed. Band-gap reorganization by the distortion of electronic structures was further confirmed by UV–visible spectrometry. Single-stack polymer electrolyte membrane fuel cell measurements showed the highly improved current density of Pt/RNb 10 TO@CNT (1.913 A cm−2 at 0.6 V) and low current degradation (6.3%) under identical conditions. We report a Nb-doped rutile TiO 2 @CNT hybrid catalyst support prepared by a facile method, namely RNb 10 TO@CNT, which exhibits enhanced activity and ultra-durability of Pt towards ORR by improved SMSI effect caused by Nb doping. [Display omitted] • Nb-doped rutile TiO 2 @CNT hybrid support was designed by a facile synthesis process. • Pt/Nb-doped rutile TiO 2 @CNT ORR catalyst showed reasonable activity and durability. • Nb doping not only controlled electronic structures but also enhanced SMSI effect. • Significantly improved sustainability was exhibited in a single-stack PEMFC cell. [ABSTRACT FROM AUTHOR]

[Display omitted] • Conjugated ladder polymer (cLP) synthesized in a flow reactor for the first time. • Multi-step synthesis was conducted in a single flow system. • Soluble cLPs obtained with controlled molecular weights (M n = 9.8–54.0 kDa) • Molecular weight-dependent material properties were characterized. The coplanar backbone of conjugated ladder polymers (cLPs) enhances electron transfer and π-π interactions, making cLPs promising materials for various applications in organic electronics and optoelectronics. Nevertheless, the limited solubility and intricate synthetic processes for cLPs make it challenging to control their molecular weight and corresponding properties, and pose as significant obstacles to their widespread application. Here, an n -type cLP, PNDI-2BocL, was synthesized using a flow reactor for the first time, with controlled molecular weights. The polymerization reaction conditions to synthesize a precursor polymer, PNDI-2Boc, were first optimized in flow, followed by sequential ladderization in batch through the injection of an acid solution. The reaction time of polymerization was varied from 7.5 to 15 min, yielding soluble PNDI-2BocL with a number-averaged molecular weight (M n) ranging from 9.8 to 54.0 kg/mol with a deviation of 11 %. Additionally, 15 min of polymerization and ladderization were successfully conducted in a single flow system sequentially for the first time. In the molecular weight-dependent studies, higher optical absorption at longer wavelengths, increased degrees of crystallinity, and higher electron mobilities in organic field-effect transistors (OFETs) were observed for higher molecular weight PNDI-2BocL. Our results highlight the importance of controlling the molecular weights of cLPs and demonstrate that the flow synthesis technique provides a viable solution for synthesizing soluble cLPs in a controlled, reproducible, and rapid manner. [ABSTRACT FROM AUTHOR]

• Soil depth affects the erosion-entrainment process of debris flow. • This study assesses and suggest soil depth mapping methods under limited data. • The uniformly set method, though efficient, risks unstable results. • Soil depth mapping affects the flow height and erosion in debris flow simulation. Soil depth is essential in studying natural disasters such as landslides and debris flow hazards. Despite the importance of soil depth in the mechanism of erosion-entrainment during the debris flow process, research on soil-depth data for analyzing debris flows is limited. Therefore, this study focused on the Gallam-ri area with a watershed of 0.9 km2 to evaluate the soil depth mapping under limited data and significance of these maps for debris flow simulations. Based on the knocking pole test data, two-dimensional distribution soil depth maps were constructed using the S and Z models, the Kriging method, and a method that applies some values uniformly as the soil depth (U model). The accuracy of soil depth mapping methods was quantitatively evaluated using R2 and root mean squared error analysis. Since soil depth demonstrated independent patterns with land-surface data, soil depth maps using S and Z models have structural limitations showing R2 of 0.0003 and 0.002, respectively. The debris flows were analyzed through numerical model Deb2D, and the soil depth most significantly influenced the erosion volume and the damaged area. Analyses using S and U models showed 94 % and 98 % high similarity to the simulation results through the Kriging method, respectively. However, considering overall analyses, the S model was analyzed to be the most stable in constructing soil depth maps and simulating debris flows for ungauged basins. [ABSTRACT FROM AUTHOR]

• A chemo-mechanical model that rigorously accounts for anisotropic features is proposed. • Anisotropic cathode materials generate four times higher stress than isotropic materials. • Anisotropic diffusivity plays a key role in higher stress of anisotropic materials. • The effect of anisotropic stress-induced diffusion on stress level is not significant. In the context of lithium-ion battery technology, LiNi x Mn y Co z O 2 (x ≥ 0.8) (Ni-rich NMC) is considered a promising cathode material for next-generation batteries due to its high energy density. However, rapid capacity fade caused by mechanical failure hinders commercialization in the battery market. Anisotropic deformation in the basal and normal directions is the main source of mechanical damage to Ni-rich NMC. In this study, we developed a fully coupled chemo-mechanical model that rigorously accounts for the anisotropic features of anisotropic diffusivity, anisotropic stress-induced diffusion and anisotropic mechanical deformation. Using the model, we investigate the effects of anisotropic and concentration-dependent lattice strains on the chemo-mechanical behavior of a single-crystalline Ni-rich NMC particle through a comparative study with the cases of a fully isotropic model, constant properties and an isotropic diffusion approximation. Numerical simulations reveal that due to the anisotropic features, Ni-rich NMC materials generate larger concentration gradients and associated higher stresses than isotropic materials, thereby enhancing the possibility of mechanical fractures. The comparative study reveals that the anisotropy in diffusivity plays an important role in high stress generation of anisotropic electrode materials. On the other hand, the anisotropy in stress-induced diffusion has small effect on the stress level of anisotropic materials; thus, isotropic approximation of the stress-induced diffusion term is reasonably allowed in the anisotropic chemo-mechanical models. The simulation results indicate that although anisotropic electrode materials are used in a single crystal structure, they are not advantageous compared to isotropic materials in terms of mechanical stability. This study provides fundamental insight into the role of the anisotropic chemo-mechanical behavior of Ni-rich cathode materials, which will help in the better design of robust, high-capacity batteries. [Display omitted] [ABSTRACT FROM AUTHOR]

Following the construction of a bacterial pan-genome from the whole genome sequences on a web-based pipeline, all coding DNA sequences (CDSs) can be clustered into pan-genome orthologous groups (POGs), which is a similar approach to comparative genome hybridization on glass microscope slides. We aimed to clarify the genomic characteristics of Streptococcus agalactiae based on the POG analysis. Sixty-six S. agalactiae isolates obtained from invasive specimens (blood and cerebrospinal fluid) and non-invasive specimens (urine and vaginal discharge) between 2010 and 2017 in Korea were subjected to whole genome sequencing (WGS). Based on the WGS data, we conducted the POG analysis and constructed a phylogenetic tree along with capsular polysaccharide (CPS) genotyping. We compared the genomics of invasive vs. non-invasive isolates, as well as CPS III vs. non-CPS III genotypes. Predicted pan- and core-genome sizes were 3416 and 1658 genes, respectively. We found four clusters consisting of CPS genotypes (III, VIII, Ib/VI, and Ia) in the phylogenetic tree. There were significant differences in two metabolic pathways specific to invasiveness, and in six metabolic pathways specific to CPS III type produced by CDSs. Our observations reveal the pan- and core-genome sizes, four clusters of genomes distributed by CPS genotypes, and unique CDS features of S. agalactiae by comparative genomics in terms of invasiveness and CPS genotype. [ABSTRACT FROM AUTHOR]

• SARS-CoV-2 was detected from various surfaces surrounding COVID-19 patients. • Extensive viral contamination was found especially around an intubated patient. • Therefore, strict contact precaution is needed in managing COVID-19 patients. Although contact precaution is generally recommended in situations where coronavirus disease 2019 (COVID-19) is suspected, there is limited evidence on environmental contamination of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Therefore, we conducted environmental surveillance on SARS-CoV-2 contamination in 2 different healthcare settings. Viral contamination was investigated on the environment of 2 hospitals that had admitted 13 COVID-19 patients. In hospital A, 5 patients with pneumonia occupied negative pressure rooms. In hospital B, 8 asymptomatic patients shared 2 common 4-bed rooms. Most rooms were poorly cleaned or disinfected. Environmental swab were collected from inside and outside the rooms and were tested using real-time RT-PCR for the detection of SARS-CoV-2. In hospital A, SARS-CoV-2 was detected in 10 of 57 (17.5%) samples from inside the rooms including the Ambu bag and infusion pump. Two samples obtained at more than 2 m from the patients showed positive results. In hospital B, 3 of 22 (13.6%) samples from inside the rooms were positive. Areas outside the rooms, such as the anteroom, corridor, and nursing station, were all negative in both hospitals. Hospital surfaces surrounding patients were contaminated by SARS-CoV-2. Our findings support the value of strict contact precaution, routine cleaning, and disinfection in the management of COVID-19 patients. [ABSTRACT FROM AUTHOR]

Highlights • We performed a cross-sectional study to evaluate syphilis serodiagnosis algorithms. • The diagnostic accuracy of reverse algorithm is superior to the traditional algorithm. • The ECDC algorithm has very good agreement with the reverse algorithm. • The ECDC algorithm has diagnostic performance enough for syphilis serodiagnosis. Abstract Objectives With the development of the automated treponemal test, new syphilis serodiagnosis algorithms, reverse algorithm, and European Centre for Disease Prevention and Control (ECDC) algorithm have been recommended recently. We investigated the efficacy of an electrochemiluminescence immunoassay (ECLIA) as an initial screening test in the reverse and ECDC algorithms. Methods Samples from 4,771 subjects were included in this study. We performed rapid plasma reagin (RPR), ECLIA, and Treponema pallidum particle agglutination (TPPA) according to these three algorithms. The fluorescent treponemal antibody absorbed (FTA-ABS) test was additionally applied for discordant cases between the RPR and ECLIA results. The FTA-ABS results and the consensus of three algorithms were considered a gold standard. Results A total of 208 subjects were diagnosed with syphilis. The traditional algorithm had a sensitivity of 25.96%, specificity of 100%, and accuracy of 96.77%. Both the reverse and ECDC algorithms showed the same diagnostic performance, sensitivity of 95.19%, specificity of 99.96%, and accuracy of 99.75%. The agreements between the traditional algorithm and the other algorithms were 96.9% with a kappa value of 0.415. Conclusions The diagnostic accuracy of the reverse and ECDC algorithms using the ECLIA as a first-line screening test was superior to that of the traditional algorithm. [ABSTRACT FROM AUTHOR]

In cyanotoxin measurements, effective release of intracellular cyanotoxins through cell lysis is pivotal. The conventional method for cell lysis is repeated freeze-thaw (F-T), which has several disadvantages, including poor reproducibility since it is operator and equipment dependency and time-consuming. In this study, a rapid and sensitive method was developed using irreversible electroporation, reducing quantification time by over 6 h compared to F-T. Focusing on microcystins (MCs), we developed the most optimal electroporation medium (50 mM Tris (pH 7.0) with 0.5 % SDS) and determined the optimal intensity of electroporation using Microcystis culture. Microcystis cell rupture was validated by scanning electron microscopy. COMSOL simulations mirrored experimental conditions. Compared to F-T, this new method generated an average 13.7 % (6.7 ppb) more MCs from lake water samples (p ≥ 0.05). This innovation, surpassing the time-consuming F-T process, emerges as a valuable tool for timely decision-making in water safety advisory and cyanotoxin management in various settings. [Display omitted] • Rapid method to release intracellular cyanotoxin is needed for bloom monitoring. • Irreversible electroporation expedites toxin release by inducing rapid cell lysis. • Electroporated cells were more ruptured than the freeze-thaw-treated cells. • Adding surfactants is effective in enhancing cell lysis during electroporation. [ABSTRACT FROM AUTHOR]

Abstract Vehicular drag coefficients in road-tunnel systems are complexly affected by traffic conditions, in terms of vehicle speed and density. Using computational fluid dynamics (CFD)-based factorial design, this study evaluates factors influencing the drag coefficient of a sedan in the Korean double-deck tunnel (KDDT) system, which divides the roadway into upper and lower levels within a single-tube tunnel. The tested factors included blockage ratio, Reynolds number, spacing ratio, and roughness height of the vehicular surface. Results showed that the blockage ratio had the most significant effect in the KDDT system, followed by the spacing ratio and the Reynolds number. A negative interaction effect was observed between the Reynolds number and spacing ratio, thereby indicating that dense traffic scenarios with fast-moving dense vehicles serve to reduce the averaged drag coefficient. In conjunction with the face-centered cube design, a response surface model (RSM) was constructed using a second-order polynomial model. For various tunnel configurations, data predicted by RSM were compared against results obtained from CFD simulations. A good agreement was observed between CFD and RSM with relative errors not exceeding 8.3% in most tunnel configurations investigated. Findings of this study suggest that the RSM can provide accurate estimates of the drag coefficient. Highlights • Factors on drag coefficient were tested systematically using numerical simulations. • We used 3D Reynolds-averaged Navier-Stokes models and factorial design method. • The blockage ratio was most significant in the Korean double-deck tunnel system. • The interaction between Reynolds number and vehicle spacing ratio was significant. • Numerical results for various tunnel configurations agreed with predicted data. [ABSTRACT FROM AUTHOR]

Fabrication of metallic matrix boron nitride nanotubes (BNNT) composites have remained challenging due to their high reactivity of metals at elevated processing temperatures. Recently, however, the successful fabrication of BNNT-metal composites has been reported using a plasma technique. Since carbon nanotubes (CNT), which are a structural analogy of BNNTs, easily react with aluminum to form aluminum carbides at the interface, serving as mechanically weak points, BNNTs can be a good alternative for the reinforcing component of metal-matrix composites (MMC). In this study, we conducted several molecular dynamics (MD) simulations to investigate the mechanical behaviors of BNNT-Al composites under tensile loading. The simulations provided quantitative information on the mechanical properties of the BNNT composite, revealing the effect of various BNNT diameters and volume fractions. The contributions of the BNNT and Al component to the total improvement of mechanical properties were quantified through a component analysis. The analysis revealed that the effect of the volume fraction of BNNTs is more significant than that of the size. In addition, the quantified relation between the volume fraction of BNNTs and the enhancement in elasticity can be effectively used for the engineering design of BNNT-Al MMCs. [ABSTRACT FROM AUTHOR]

The generation of molecular active species on the surface of nano-materials has become promising routes to produce efficient electrocatalysts. Development of cost-effective catalysts with high performances for oxygen reduction reaction (ORR) is an important challenge for fuel cell and metal-air battery applications. In this work, we report a novel hybrid produced by room-temperature solution processes using Ni-based organometallic molecules and N -doped graphene-based materials. Chemical and structural characterizations reveal that Ni-containing species are well-dispersed on the surface of graphene network as molecular entity. The hybrid shows excellent electrocatalytic performances for ORR in basic medium with an onset potential of 0.87 V (vs. RHE), superior durability and good methanol tolerance. [ABSTRACT FROM AUTHOR]

Chemical investigation of the EtOAc extract of a marine-derived fungal isolate Penicillium sp. SF-5292 yielded a new polyketide-type metabolite, penicillospirone ( 1 ). The structure of 1 was determined by analysis of spectroscopic data such as 1D and 2D NMR spectra and MS data, and the final structure including absolute configuration was unambiguously established by single-crystal X-ray diffraction analysis. In the evaluation of its anti-inflammatory effects, 1 inhibited the overproduction of nitric oxide (NO) and prostaglandin E 2 (PGE 2 ) in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and BV2 microglia, and these inhibitory effects were correlated with the suppressive effect of 1 against overexpressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Furthermore, 1 also inhibited the production of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, and IL-12. Overall, the anti-inflammatory effect of 1 was suggested to be mediated through the negative regulation of NF-κB pathway. [ABSTRACT FROM AUTHOR]

Chlorinated volatile organic compounds (CVOCs) have received attention as hazardous air contaminants for decades, and a complete oxidation process of CVOCs using an efficient catalyst should be most effective to handle such hazardous materials. A series of CuO x -supported on Al-Ti mixed oxide catalysts were prepared by sol-gel method for the mixed oxide support and followed by wet impregnation method for the CuO x nanoparticles formation on the support. These Cu/Al-Ti composite catalysts were investigated for catalytic complete oxidation of 1,2-dichloroethane (DCE), which is one representative CVOCs. Through combining each transition metal components that having different catalytic properties with appropriate composition, excellent catalytic performances in terms of activity and selectivity for the catalytic oxidation of DCE were obtained on the resultant Cu/Al-Ti composite catalysts. The design strategy of composite catalyst studied in this work should suggest the way for efficient and sustainable removal of CVOCs using nonprecious catalytic materials. [Display omitted] • Cu/Al-Ti catalysts were used for complete oxidation of 1,2-dichloroethane. • Synergy effect of acidic and redox properties enhanced catalytic performances. • According to the amount of Cu contents, systematic tendencies were observed. • Appropriate composition was needed for effective and desirable CVOCs destruction. [ABSTRACT FROM AUTHOR]

Fe-based hybrid systems have been suggested as promising candidates for oxygen reduction reaction (ORR) catalysts owing to their good catalytic performances and feasibilities for mass production at low cost. In this work, we develop means of producing novel hybrids containing FeOOH particles well-dispersed on graphene-based materials using a one-pot solution process. The hybrid materials show good electrochemical catalytic activity for ORR, such as, an on-set potential of 0.76 V (vs. the reversible hydrogen electrode), a near four electron pathway, and excellent stability against methanol poisoning during durability test. This is the first report of the use of FeOOH/reduced graphene oxide hybrid materials as ORR catalysts. [ABSTRACT FROM AUTHOR]