Structural characteristics of sediment humins from South Korean lakes and their phenanthrene binding compared to other carbon sources.

Sediment humins are extremely important for binding hydrophobic organic contaminants in rivers and lakes. Nonetheless, little is known about their structure and binding. We, therefore, examined the structure and phenanthrene sorption affinity of sediment humin samples upstream, midstream, and downstream from two artificial lakes in South Korea by using the elemental 13C-NMR analysis, Freundlich model, and Langmuir model. The characteristics and phenanthrene sorption affinity of sediment humins were also compared with those of sediment humic acids from similar origins as well as soil humins/humic acids in South Korea from previous studies by using principal component analysis. In both lakes, downstream sediment humins exhibited lower N/C, O/C, and (N + O)/C ratios, lower internal oxidation, and higher aliphaticity due to the presence of long-chain aliphatic compounds generated during anaerobic decomposition. The principal component analysis results also showed that C,H-alkyl, O-alkyl, and polar organic carbon contents were significantly different when comparing the up-mid stream and downstream sediment samples in Daecheong Lake. In addition, midstream sediment humin in Andong Lake presented higher C,H-alkyl and lower polar organic carbon contents compared to those of up-downstream samples. In both lakes, the sorption coefficient and adsorption isotherm linearity were positively correlated with the C,H-alkyl content and negatively correlated with the O-aryl content. Similar to C,H-alkyl and POC, C,H-alkyl, and (N + O)/C had an extremely high correlation coefficient when predicting the sorption coefficient (Freundlich model) and the maximum adsorption capacity (Langmuir model) of sediment humins. Sediment humins had higher C,H-alkyl contents and lower sorption coefficients than those of sediment humic acids and soil humins/humic acids. These findings provide key information for monitoring water quality and polycyclic aromatic hydrocarbon contamination in South Korean lake sediments.

Improved synaptic functionalities of Li-based nano-ionic synaptic transistor with ultralow conductance enabled by Al2O3barrier layer.

In this study, we investigated the effect of an Al2O3barrier layer in an all-solid-state inorganic Li-based nano-ionic synaptic transistor (LST) with Li3PO4electrolyte/WOxchannel structure. Near-ideal synaptic behavior in the ultralow conductance range (∼50 nS) was obtained by controlling the abrupt ion migration through the introduction of a sputter-deposited thin (∼3 nm) Al2O3interfacial layer. A trade-off relationship between the weight update linearity and on/off ratio with varying Al2O3layer thickness was also observed. To determine the origin of the Al2O3barrier layer effects, cyclic voltammetry analysis was conducted, and the optimal ionic diffusivity and mobility were found to be key parameters in achieving ideal synaptic behavior. Owing to the controlled ion migration, the retention characteristics were considerably improved by the Al2O3barrier. Finally, a highly improved pattern recognition accuracy (83.13%) was achieved using the LST with an Al2O3barrier of optimal thickness.

Competitive adsorption of heavy metals onto modified biochars: Comparison of biochar properties and modification methods.

Various biochars (BCs) have been developed to remove heavy metals contained in road runoff; however, there is insufficient information regarding the competitive adsorption efficiency of modified BC with regard to heavy metals due to a lack of comparative evaluation based on BC properties and modification methods. In this study, three different types of BC (RBC: rice husk, WBC: wood chip, MBC: mixture) were modified following five different methods: acidic, alkaline, oxidic, and manganese oxide (MnOx) and iron oxide (FeOx) impregnation. The changes in the physicochemical and morphological properties of the modified BC were investigated, and the adsorption characteristics of three heavy metals (Cd, Pb, and Zn) under single and mixed conditions were compared and evaluated. The improvements in the BC properties varied for different BC types and modification methods; in particular, alkaline and manganese modification caused substantial the changes in the surface area and functional groups (such as aromatic ring, -OH, and Mn-O groups). The BC prepared by manganese oxide impregnation absorbed a high amount of heavy metals (>9.15 mg/g) even under mixed conditions through cation exchange and surface complexation. The distribution coefficient (Kd) of heavy metals was high in the order of Pb > Cd > Zn; thus, the adsorption of Pb replaced that of Zn in competitive adsorption due to the difference in their affinity to BC. Therefore, the results suggest that BC prepared by manganese oxide impregnation is suitable for removing heavy metals from road runoff, as it maintained high heavy metals adsorption regardless of the BC material, even under competitive conditions.

Combined dual-size foam glass media filtration process with micro-flocculation for simultaneous removal of particulate and dissolved contaminants in urban road runoff.

In this study, a combined media filtration process with micro-flocculation (CMF) was developed, to simultaneously treat particulate and dissolved contaminants in urban road runoff. Dual-size foam glass media with stone and sand layers were applied and the efficiency of road runoff treatment was investigated according to filtration and micro-flocculation under various experimental conditions (stone/sand layer ratio, linear velocity, and coagulant types). Moreover, the removal efficiencies of suspended solids (SS), phosphorus, organic carbon, and heavy metals (Zn, Cu, Pb, Cd) by CMF were evaluated. The removal rate of SS was maintained to be above 84.1% for 1 h filtration by the dual-size foam glass, regardless of increasing pressure. The removal of phosphorus by micro-flocculation was more suitable in alum than ferric due to a higher initial floc growth rate and an increased particle size. The performance of the CMF was significantly improved over media filtration only process (MF) in removing both particulate and dissolved contaminants. The removal efficiency of all particulate pollutants by CMF was found to be more than 90%, and notably, the dissolved phosphorus, which was mostly not removed by MF, was also removed by 97.4%. Meanwhile, the backwash efficiency of CMF was half that of MF. Physical removal mechanisms, such as internal diffusion, dominated MF, whereas chemical removal mechanisms, such as adsorption and surface precipitation, dominated CMF. These results show the potential of the CMF process for the treatment of urban road runoff and identify the removal mechanisms of the filtration process that use micro-flocculation with dual-size foam glass.

Enhancing the total organic carbon measurement efficiency for water samples containing suspended solids using alkaline and ultrasonic pretreatment methods.

In this study, we investigated the effect of sample pretreatments (ultrasonication and alkaline extraction) on total organic carbon (TOC) measurements for water samples containing suspended solids (SS) of four different origins (algae, soil, sewage sludge, and leaf litter) to more clearly assess the impact of particulate organic carbon (POC) in water. The effects each of ultrasonication (power, pulse, etc.) and alkaline extraction condition (concentration, time, etc.) on the TOC recovery and precision were investigated, and the results were compared with those of a new sample pretreatment method combining both methods. Alkaline treatment (0.01 mol/L NaOH) showed higher precision than ultrasonication (100/5 on/off pulse), and notably, the differences among the measured TOC values in samples of different origins were also further reduced in the alkaline treatment. This suggests that the ultrasonic pretreatment results can be mainly attributed to the increase in POC recovery through particle size reduction, whereas the alkaline treatment results are achieved through the enhancement of POC solubilization. It is also particularly noteworthy that a higher TOC recovery of 87.6% ± 7.4% with a higher precision of 8.4% could be obtained using the combined method, compared to each treatment (ultrasonic: TOC recovery 34.7%, relative standard deviation 63.1%; alkaline: 49.6% and 23.0%, respectively). Thus, simultaneous pretreatment with ultrasonication and alkaline extraction is expected to increase the oxidation rate of organic matter and the homogeneity of the samples, minimizing the loss of POC measurement values, and thereby improving the reliability of the TOC measurements of water samples containing SS.

Construction of the safe neutralizing assay system using pseudotyped Nipah virus and G protein-specific monoclonal antibody.

Nipah virus (NiV) is a recently emerged paramyxovirus that causes acute respiratory illness and fatal encephalitis in a broad spectrum of vertebrates, including humans. Due to its high pathogenicity and mortality rates, NiV requires handling in biosafety level-4 (BSL-4) containment facilities and no effective vaccines or therapeutic agents are currently available. Since current diagnostic tests for detecting serum neutralizing antibodies against NiV mainly employ live viruses, establishment of more safe and robust alternative diagnostic methods is an essential medical requirement. Here, we have developed a pseudotyped NiV and closely related Hendra virus (HeV) expressing envelope attachment (G) and fusion (F) glycoproteins using the Moloney murine leukemia virus (MuLV) packaging system. We additionally generated polyclonal antibodies (pAbs) against NiV-G and HeV-G and assessed their neutralizing activities for potential utilization in the pseudovirus-based neutralization assay and further application in the serum diagnostic test. To enhance the specificity of neutralizing antibody and sensitivity of the serological diagnostic test, monoclonal antibodies (mAbs) against NiV-G were generated, and among which four out of six mAb clones showed significant reactivity. Specifically, the 7G9 clone displayed the highest sensitivity. The selected mAb clones showed no cross-reactivity with HeV-G and efficient neutralizing activities against pseudotyped NiV. These results validate the safety and specificity of neutralization assays against NiV and HeV and present a useful tool to design effective vaccines and serological diagnosis.

The difference of morphological characteristics and population structure in PAO and DPAOgranular sludges.

We examined how long-term operation of anaerobic-oxic and anaerobic-anoxic sequencing batch reactors (SBRs) affects the enhanced biological phosphorus removal (EBPR) performance and sludge characteristics. The microbial characteristics of phosphorus accumulating organism (PAO) and denitrifying PAO (DPAO) sludge were also analyzed through a quantitative analysis of microbial community structure. Compared with the initial stage of operation characterized by unstable EBPR, both PAO and DPAO SBR produced a stable EBPR performance after about 100-day operation. From day 200 days (DPAO SBR) and 250 days (PAO SBR) onward, sludge granulation was observed, and the average granule size of DPAO SBR was approximately 5 times larger than that of PAO SBR. The DPAO granular sludge contained mainly rod-type microbes, whereas the PAO granular sludge contained coccus-type microbes. Fluorescence in situ hybridization analysis revealed that a high ratio of Accumulibacter clade I was found only in DPAO SBR, revealing the important role of this organism in the denitrifying EBPR system. A pyrosequencing analysis showed that Accumulibacter phosphatis was present in PAO sludge at a high proportion of 6%, whereas it rarely observed in DPAO sludge. Dechloromonas was observed in both PAO sludge (3.3%) and DPAO sludge (3.2%), confirming that this organism can use both O2 and NO3- as electron acceptors. Further, Thauera spp. was identified to have a new possibility as denitrifier capable of phosphorous uptake under anoxic condition.

Bioconverted Orostachys japonicas Extracts Suppress Angiogenic Activity of Ms-1 Endothelial Cells.

Orostachys japonicus A. Berger (), known as Wa-song in Korea, has been reported to exert various biological effects, such as anti-tumor, anti-oxidant, and anti-febrile effects. However, the anti-angiogenic effects of O.japonicus extracts remain to be investigated. In the present study, we demonstrated the anti-angiogenic effects of bioconverted O. japonicus extract (BOE) in Ms-1 mouse endothelial cells and compared them with the bioactivities of O. japonicus extract (OE). BOE, but not OE, were found to exert anti-angiogenic effects, including inhibition of cell migration, cell adhesion, tube formation of Ms-1 cells, and blood vessel formation of matrigel plug assay in vivo. Furthermore, protein levels of phosphorylated Src kinase were lower in BOE-treated cells than in OE-treated cells. Treatment with OE or BOE did not influence cell viability during the experimental period. Bioconverted extract of O.japonicus have anti-angiogenic effects in vitro and vivo, but non-bioconverted extract do not. We suggest that these observed anti-angiogenic effects are caused by the changes in the composition of bioactive compounds in the extracts as a result of biological conversion.

Comparison of Antibiotic Resistance Removal Efficiencies Using Ozone Disinfection under Different pH and Suspended Solids and Humic Substance Concentrations.

This study mainly evaluated the effectiveness of ozonation toward the enhancement of the removal efficiencies of antibiotic-resistant bacteria (ARB), pB10 plasmid transfer, and pB10 plasmids under different pH and suspended solids (SS) and humic acid concentrations. First, chlorination was tested as a reference disinfection process. Chlorination at a very high dose concentration of Cl2 (75 mg L(-1)) and a long contact time (10 min) were required to achieve approximately 90% ARB and pB10 plasmid transfer removal efficiencies. However, even these stringent conditions only resulted in a 78.8% reduction of pB10 plasmid concentrations. In case of ozonation, the estimated CT (concentration × contact time) value (at C0 = 7 mg L(-1)) for achieving 4-log pB10 plasmid removal efficiency was 127.15 mg·min L(-1), which was 1.04- and 1.25-fold higher than those required for ARB (122.73 mg·min L(-1)) and a model nonantibiotic resistant bacterial strain, E. coli K-12, (101.4 mg·min L(-1)), respectively. In preventing pB10 plasmid transfer, ozonation achieved better performance under conditions of higher concentrations of humic acid and lower pH. Our study results demonstrated that the applicability of CT concept in practice, conventionally used for disinfection, might not be appropriate for antibiotic resistance control in the wastewater treatment process. Further studies should be conducted in wastewater engineering on how to implement multiple barriers including disinfection to prevent ARB and ARG discharge into the environment.

Comparison of biochemical characteristics between PAO and DPAO sludges.

A successful enhanced biological phosphorus removal (EBPR) was observed in both anaerobic-aerobic sequencing batch reactor (An-Ox SBR) to induce growth of phosphorus accumulating organism (PAO) and anaerobic-anoxic (An-Ax) SBR to induce growth of denitrifying PAO (DPAO). Although the EBPR performance of An-Ox SBR was higher by 11.3% than that of An-Ax SBR, specific phosphorus release rates in the An-Ax SBR (22.8 ± 3.5 mg P/(g VSS·hr)) and the An-Ox SBR (22.4 ± 4.8 mg P/(g VSS·hr)) were similar. Specific phosphorus uptake rates under anoxic and aerobic conditions were 26.3 ± 4.8 mg P/(g VSS·hr) (An-Ax SBR) and 25.6 ± 2.8 mg P/(g VSS·hr) (An-Ox SBR), respectively, which were also similar. In addition, an analysis of relationship of poly-ß-hydroxyalkanoates (PHA) synthesized under anaerobic conditions with phosphorous release (Preleased/PHA synthesized) and of PHA utilized under anoxic and aerobic conditions with phosphorous uptake (Puptaked/PHAutilized) verified that biological activities of EBPR per unit biomass between DPAO and PAO were similar. An analysis of the specific denitrification rate of DPAO showed that NO(-)3-N can be denitrified at a rate that does not substantially differ from that of an ordinary denitrifier without additional consumption of organic carbon when the PHA stored inside the cell under anaerobic conditions is sufficiently secured.

Anoxic gas recirculation system for fouling control in anoxic membrane reactor.

Anoxic gas recirculation system was applied to control the membrane fouling in pilot-scale 4-stage anoxic membrane bioreactor (MBR). In the anaerobic-anoxic-anoxic-aerobic flow scheme, hydrophilic polytetrafluoroethylene (PTFE) membrane (0.2 µm, 7.2 m(2)/module) was submerged in the second anoxic zone. During 8 months operation, the average flux of the membrane was 21.3 L/(m(2)·hr). Chemical cleaning of the membrane was conducted only once with sodium hydroxide and sodium hypochlorite. Dissolved oxygen (DO) concentration in the second anoxic zone was maintained with an average of 0.19 ± 0.05 mg/L. Gas chromatography analysis showed that the headspace gas in the second anoxic reactor was mainly consisted of N2 (93.0% ± 2.5%), O2 (3.8% ± 0.6%), and CO2 (3.0% ± 0.5%), where the saturation DO concentration in liquid phase was 1.57 mg/L. Atmospheric O2 content (20.5% ± 0.8%) was significantly reduced in the anoxic gas. The average pH in the reactor was 7.2 ± 0.4. As a result, the recirculation of the anoxic gas was successfully applied to control the membrane fouling in the anoxic MBR.

Characterization of high-affinity antibodies against the surface Gc protein of Dabie bandavirus / severe fever with thrombocytopenia syndrome virus.

Severe fever with thrombocytopenia syndrome virus (SFTSV) or Dabie bandavirus is an emerging pathogen responsible for SFTS. It is considered a novel threat to human health, given the high associated fatality. SFTSV is a segmented negative-strand RNA virus containing three single-stranded RNAs, with the M segment encoding the glycoproteins Gn and Gc. Gc is vital for viral entry into the host cell surface, along with the Gn protein. As the Gc is the surface-exposable antigen from virions, it is a critical diagnostic marker of infection. Although various SFTSV Gn or N protein-based sero-diagnostic methods have been developed, there are no commercially available sero-diagnostic kits. Therefore, we generated monoclonal antibodies (mAbs) against SFTSV Gc and explored their application in serum diagnostic tests to develop sensitive serodiagnostic tools covering broad-range genotypes (A to F). First, 10 SFTSV Gc antibody-binding fragments (Fabs) were isolated using a phage display system and converted into human IgGs. Enzyme-linked immunosorbent assays (ELISA) of the SFTSV and Rift Valley fever virus (RVFV: same genus as SFTSV) Gc antigens showed that all antibodies attached to the SFTSV Gc protein had high affinity. An immunofluorescence assay (IFA), to verify the cross-reactivity of seven antibodies with high affinities for various SFTSV genotypes (A, B2, B3, D, and F) and detect mAb binding with intact Gc proteins, revealed that five IgG type mAbs were bound to intact Gc proteins of various genotypes. Six high-affinity antibodies were selected using ELISA and IFA. The binding capacity of the six antibodies against the SFTSV Gc antigen was measured using surface plasmon resonance. All antibodies had high binding capacity. Consequently, these antibodies serve as valuable markers in the serological diagnosis of SFTSV.

Highly Reliable Magnetic Memory-Based Physical Unclonable Functions.

Magnetic random-access memory (MRAM), which stores information through control of the magnetization direction, offers promising features as a viable nonvolatile memory alternative, including high endurance and successful large-scale commercialization. Recently, MRAM applications have extended beyond traditional memories, finding utility in emerging computing architectures such as in-memory computing and probabilistic bits. In this work, we report highly reliable MRAM-based security devices, known as physical unclonable functions (PUFs), achieved by exploiting nanoscale perpendicular magnetic tunnel junctions (MTJs). By intentionally randomizing the magnetization direction of the antiferromagnetically coupled reference layer of the MTJs, we successfully create an MRAM-PUF. The proposed PUF shows ideal uniformity and uniqueness and, in particular, maintains performance over a wide temperature range from -40 to +150 °C. Moreover, rigorous testing with more than 1584 challenge-response pairs of 64 bits each confirms resilience against machine learning attacks. These results, combined with the merits of commercialized MRAM technology, would facilitate the implementation of MRAM-PUFs.

Photochemical and microbial transformation of particulate organic matter depending on its source and size.

Particulate organic matter (POM) in water systems can be converted into dissolved organic matter (DOM) through various pathways depending on its properties and transformation. Thus, information on the behavior of POM is crucial for fully understanding water systems and the carbon cycle. In this study, the effects of particle size and the source of POM, as well as photochemical and microbial changes in DOM characteristics subsequently released from POM were evaluated using various spectral indices, excitation-emission matrix combined with parallel factor analysis components, and principal component analysis. The amount of dissolved organic carbon (DOC) released from POM during suspension was significantly associated with the carbon content of POM (p < 0.05). The amount of DOC (mg-C/g-SS) decreased in mineral-bound POM as a result of microbial degradation but increased in biogenic POM as a result of microbial dissolution, owing to the structural differences in organic matter from different sources. Mineral-bound POM showed more DOC production by photochemical desorption than microbial degradation, whereas biogenic POM displayed the opposite trend. The DOM derived from fine POM had more humified terrestrial humic-like substances than those derived from coarse POM. Principal components 1 and 2 were associated with DOC production and degree of humification, respectively. The increase in the degree of aromaticity and humification of organic matter was higher in mineral-bound POM by photochemical desorption of highly humified organic matter and in the biogenic POM by microbial dissolution. In conclusion, this study was able to provide basic information on the transformation of POM, thus, it is expected to broaden the knowledge of the biogeochemical cycle of organic matter.

Proposal for a new customization process for a data-based water quality index using a random forest approach.

As the water quality index (WQI) represents water quality, it is crucial to customize the WQI for a specific purpose. In this study, to better represent water quality data using WQI, a random forest (RF) approach was used to derive the parameter weight and calculate the WQI according to the watershed and its use. Eight parameters (water temperature, dissolved oxygen, pH, electrical conductivity, suspended solids, total nitrogen, total phosphorus, and total organic carbon) were evaluated using a total of 220,103 data points collected from 900 monitoring sites throughout South Korea between 2011 and 2020. The estimation of parameter weights, key elements in developing the WQI model, was performed through the variable importance estimation method that can be derived from the RF model. The parameter weights were derived based on various spatiotemporal datasets, and it was confirmed that the spatiotemporal differences in weights according to data characteristics represented the regional and seasonal water quality characteristics. Consequently, a customized WQI representing water quality characteristics could be calculated using data-based weights, and it is expected that a data-based customized WQI could be developed to better match the previous WQI to the purpose and target source.

Identification of the cause of the difference among TOC quantitative methods according to the water sample characteristics.

Total organic carbon (TOC) analysis with accurate determination of particulate organic carbon (POC) content in suspended solids (SS) containing water is critical for evaluating the environmental impact of particulate organic pollutants in water and calculating the carbon cycle mass balance. TOC analysis is divided into the non-purgeable organic carbon (NPOC) and differential (known as TC-TIC) methods; although the selection of method is greatly affected by the sample matrix characteristics of SS, no studies have investigated this. This study quantitatively evaluates the effect of SS containing inorganic carbon (IC) and purgeable organic carbon (PuOC), as well as that of sample pretreatment, on the accuracy and precision of TOC measurement in both methods for various environmental water sample types (12 wastewater influents and effluents and 12 types of stream water). For influent and stream water with high SS, the TC-TIC method expressed 110-200 % higher TOC recovery than that for the NPOC method due to POC component losses in SS owing to its conversion into PuOC during sample pretreatment (using ultrasonic) and subsequent loss in the NPOC purging process. Correlation analysis confirmed that particulated organic matter (POM, mg/L) content in SS directly affected this difference (r > 0.74, p < 0.01, n = 24); for POC water samples (those containing >10 mg/L of POM) featuring purgeable dissolved organic matter, TC-TIC was appropriate in securing TOC measurement accuracy. In constrast, in effluent and stream water with low SS (i.e., < ∼5 mg/L) and high IC (> 70 %) contents, the TOC measurement ratios (TC-TIC/NPOC) of both methods were similar, between 0.96 and 1.08, suggesting that NPOC is appropriate for improving precision. Our results provide useful basic data to establish the most reliable TOC analysis method considering SS contents and its properties along with the matrix characteristics of the sample.

Investigating the different transformations of tetracycline using birnessite under different reaction conditions and various humic acids.

Prior studies have successfully used manganese oxides to facilitate the transformation of tetracycline in aqueous solution. To further understand the kinetic and the transformation pathway of tetracycline via birnessite (δ-MnO2) under different conditions, experiments were conducted at pH levels of 3, 6, and 9 in the presence or absence of Aldrich humic acid (ADHA). Tetracycline removal followed the pseudo-second-order reaction model in all investigated cases, and the removal efficiency (g mg-1 h -1) followed the following trend: pH 3 (0.45/0.27) > pH 6 (0.036/0.087) > pH 9 (0.036/0.103) in the absence/presence of ADHA. Liquid chromatography-mass spectrometry/mass spectrometry results identified five main transformation products at m/z 495, 477, 493, 459, and 415, produced by the transformation reactions, including hydration, oxidation, desaturation, and oxy reduction. Notably, in the presence of ADHA at pH 3, products with higher toxicity secondary (m/z 477 and 495) were reduced, while less toxicity products (m/z 459 and 415) were enhanced. The experiments utilizing tetracycline and δ-MnO2 with varied humic acids (HA) revealed that HA with high polar organic carbon groups, such as O-alkyl, exhibited higher removal efficiency at pH 6. This research offers the first comprehensive insights into the pathway transformations of tetracycline via δ-MnO2 under different pH conditions and HA types. For further understanding, future work should investigate the binding of HA, TTC, and/or Mn2+ and the oxidation capacity of MnO2 after the reaction to clarify Mn2+ elution mechanisms.

Comparing the Immunogenicity and Protective Effects of Three MERS-CoV Inactivation Methods in Mice.

The Middle East respiratory syndrome (MERS) is a fatal acute viral respiratory disease caused by MERS-coronavirus (MERS-CoV) infection. To date, no vaccine has been approved for MERS-CoV despite continuing outbreaks. Inactivated vaccines are a viable option when developed using the appropriate inactivation methods and adjuvants. In this study, we evaluated the immunogenicity and protective effects of MERS-CoV vaccine candidates inactivated by three different chemical agents. MERS-CoV was effectively inactivated by formaldehyde, hydrogen peroxide, and binary ethylene imine and induced humoral and cellular immunity in mice. Although inflammatory cell infiltration was observed in the lungs four days after the challenge, the immunized hDPP4-transgenic mouse group showed 100% protection against a challenge with MERS-CoV (100 LD50). In particular, the immune response was highly stimulated by MERS-CoV inactivated with formaldehyde, and all mice survived a challenge with the minimum dose. In the adjuvant comparison test, the group immunized with inactivated MERS-CoV and AddaVax had a higher immune response than the group immunized with aluminum potassium sulfate (alum). In conclusion, our study indicates that the three methods of MERS-CoV inactivation are highly immunogenic and protective in mice and show strong potential as vaccine candidates when used with an appropriate adjuvant.

Spatiotemporal Evaluation of Water Quality and Hazardous Substances in Small Coastal Streams According to Watershed Characteristics.

In this study, spatial and temporal changes of eight water quality indicators and 30 types of hazardous substances including volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), pesticides, and inorganic matters for the small coastal streams along the West Coast of South Korea were investigated. In coastal streams with clear seasonal changes in water quality, larger watershed areas led to greater contamination by particulate matter (i.e., suspended solids, r = 0.89), and smaller watershed areas led to greater contamination by organic matter (i.e., BOD, r = -0.78). The concentration of VOCs and pesticides was higher in agricultural areas, and those of SVOCs and metals were often higher in urban areas. According to the principal component analysis (PCA), during the wet season, the fluctuation in the water quality of coastal streams was higher in urban areas than in agricultural areas. Furthermore, coastal streams in residential areas exhibited higher levels of SVOCs, and those in industrial areas exhibited higher levels of metallic substances. Based on these results, the spatial and temporal trends of water quality and hazardous substances were obtained according to watershed characteristics, thereby clarifying the pollution characteristics of small-scale coastal streams and the major influencing factors.

J2N-k hamster model simulates severe infection caused by severe acute respiratory syndrome coronavirus 2 in patients with cardiovascular diseases.

Considering the global impact of the coronavirus disease 2019 (COVID-19) pandemic, generating suitable experimental models is imperative. For pre-clinical studies, researchers require animal models displaying pathological features similar to those observed in patients; therefore, establishing animal models for COVID-19 is crucial. The golden Syrian hamster model mimics conditions observed in humans with mild severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, a golden Syrian hamster model of severe infection has not been reported. J2N-k hamsters are utilized as a cardiomyopathy model; therefore, we used cardiomyopathic J2N-k hamsters showing conditions similar to those of severe COVID-19 complicated with cardiovascular diseases, as patients with cardiovascular diseases exhibit a higher risk of morbidity and mortality due to COVID-19 than patients without cardiovascular diseases. Unlike that in golden Syrian hamsters, SARS-CoV-2 infection was lethal in J2N-k hamsters, with a median lethal dose of 104.75 plaque-forming units for the S clade of SARS-CoV-2 (A, GenBank: MW466791.1). High viral titers and viral genomes were detected in the lungs of J2N-k and golden Syrian hamster models harvested 3 days after infection. Pathological features of SARS-CoV-2-associated lung injury were observed in both models. The J2N-k hamster model can aid in developing vaccines or therapeutics against COVID-19.