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The primary moisture separator—a key component in the PWR nuclear power plant—determines the quality of supplied steam to a turbine. Investigating its characteristics is important because supplying steam with excessive droplet entrainment results in damages to pipes, valves, and turbines in power plant circuits. In this numerical study, the particle tracking method in the Eulerian–Lagrangian methodology is used to investigate the characteristics of a primary moisture separator. Various swirl vanes with different bending angles, vane quantities, and vane locations are chosen to investigate the effect of design parameters on characteristics of the primary moisture separator. Additionally, the water droplet size is considered to vary from 0.01 to 50 μm in this study. The pressure drop between the inlet and outlet, the steam quality at the orifice outlet, and the particle collection ratio are discussed in this paper. The results show that steam quality increases as the bending angle decreases, and increasing the number of swirl vanes increases both the pressure drop and the steam quality.

Clostridium botulinum produces one of the most potent biological toxins and causes botulism, a rare but potentially fatal neuroparalytic disease. In 2014, a foodborne botulism case was reported in Korea, and a strain (CB-2014001) was isolated. Initial characterization identified it as a BoNT/B-producing strain based on mouse bioassay and conventional PCR. However, subsequent genomic analysis revealed the presence of dual BoNT gene clusters, bont/B and bont/F, corresponding to subtypes B5 and F2, respectively. Therefore, we aimed to analyze the genetic characteristics and toxin expression profiles of the isolated strain. The strain showed high sequence identity with Bf-type strains such as CDC 3281 and An436. Functional assays confirmed simultaneous expression of both BoNT/B and /F toxins at 35 °C, and temperature-dependent assays revealed predominant expression of BoNT/F at 30 °C and BoNT/B at 37 °C, indicating that toxin expression is influenced by environmental temperature. These findings highlight the potential for differential pathogenicity based on culture conditions and underscore the importance of developing diagnostic tools capable of detecting multiple bont genes. To our knowledge, this is the first report of a dual-toxin-producing C. botulinum strain associated with foodborne botulism in Korea, providing important insights into botulism diagnosis, treatment strategies, and public health preparedness.

•The immunogenicity and efficacy of GC1109 were tested using A/J mice model.•A booster dose of GC1109 after 3 serial vaccinations enhanced the level of anti-PA IgG and toxin-neutralizing capacity.•Correlation between TNA NF50 titer and survival was observed.•A TNA NF50 of 0.21 corresponded to 70 % probability of protection in A/J mice. A recombinant protective antigen anthrax vaccine (GC1109) is being developed as a new-generation vaccine by the Korea Disease Control and Prevention Agency. In accordance with the ongoing step 2 of phase II clinical trials, the immunogenicity and protective efficacy of the booster dose of GC1109 were evaluated in A/J mice after 3 serial vaccinations at 4-week intervals. The results indicated that the booster dose significantly increased the production of anti-protective antigen (PA) IgG and toxin-neutralizing antibody (TNA) compared with those of the group without booster. An enhanced protective effect of the booster dose was not observed because the TNA titers of the group without booster were high enough to confer protection against spore challenge. Additionally, the correlation between TNA titers and probability of survival was determined for calculating the threshold TNA titer levels associated with protection. The threshold 50 % neutralization factor (NF50) of TNA showing 70 % probability of protection was 0.21 in A/J mice with 1,200 LD50 Sterne spores challenge. These results indicate that GC1109 is a promising candidate as a new-generation anthrax vaccine and that a booster dose might provide enhanced protection by producing toxin-neutralizing antibodies.

Background: Botulinum neurotoxins (BoNTs), produced by Clostridium botulinum, are potent protein toxins that can cause botulism, which leads to death or neuroparalysis in humans by targeting the nervous system. BoNTs comprise three functional domains: a light-chain enzymatic domain (LC), a heavy-chain translocation domain (HCN), and a heavy-chain receptor-binding domain (HCC). The HCC domain is critical for binding to neuronal cell membrane receptors and facilitating BoNT internalization via endocytosis. Accordingly, it may serve as a vaccine candidate, inducing anti-BoNT-neutralizing antibodies in animals. Here, we aimed to develop a vaccine capable of simultaneously defending against both BoNT/A and B. Methods: We combined the HCC domains of botulinum neurotoxin type A (BoNT/A) and botulinum neurotoxin type B (BoNT/B) in Escherichia coli to produce a recombinant protein (rHCCB-L-HCCArHCcB) that offers dual protection against both toxins by inhibiting their receptor binding. To evaluate the efficacy of the vaccine, mice were immunized intramuscularly with rHCCB-L-HCCA plus alum thrice at 2-week intervals, followed by the assessment of immunogenicity and protective efficacy. Results: The antibody titer in mice immunized with rHCCB-L-HCCA was significantly higher than that in mice immunized with alum alone, protecting them from the lethal challenges of BoNT/A (105 50% lethal dose, LD50) and B (103 LD50). Conclusion: These findings suggest that rHCCB-L-HCCA may simultaneously be an effective vaccine candidate against BoNT/A and B.

This study was undertaken to evaluate the effect of 3D printed polycaprolactone (PCL)/β-tricalcium phosphate (β-TCP) scaffold containing bone demineralized and decellularized extracellular matrix (bdECM) and human recombinant bone morphogenetic protein-2 (rhBMP-2) on bone regeneration. Scaffolds were divided into PCL/β-TCP, PCL/β-TCP/bdECM, and PCL/β-TCP/bdECM/BMP groups. In vitro release kinetics of rhBMP-2 were determined with respect to cell proliferation and osteogenic differentiation. These three reconstructive materials were implanted into 8 mm diameter calvarial bone defect in male Sprague-Dawley rats. Animals were sacrificed four weeks after implantation for micro-CT, histologic, and histomorphometric analyses. The findings obtained were used to calculate new bone volumes (mm3) and new bone areas (%). Excellent cell bioactivity was observed in the PCL/β-TCP/bdECM and PCL/β-TCP/bdECM/BMP groups, and new bone volume and area were significantly higher in the PCL/β-TCP/bdECM/BMP group than in the other groups ( p < . 05 ). Within the limitations of this study, bdECM printed PCL/β-TCP scaffolds can reproduce microenvironment for cells and promote adhering and proliferating the cells onto scaffolds. Furthermore, in the rat calvarial defect model, the scaffold which printed rhBMP-2 loaded bdECM stably carries rhBMP-2 and enhances bone regeneration confirming the possibility of bdECM as rhBMP-2 carrier.

Rapid and sensitive detection of botulinum neurotoxins (BoNTs) is important for immediate treatment with proper antitoxins. However, it is difficult to detect BoNTs at the acute phase of infection, owing to its rarity and ambiguous symptoms. To resolve this problem, we developed a surface-enhanced Raman scattering (SERS)-based immunoassay technique for the rapid and sensitive detection of BoNTs. Magnetic beads and SERS nanotags as capture substrates and detection probes, respectively, and Nile Blue A (NBA) and malachite green isothiocyanate (MGITC) as Raman reporter molecules were used for the detection of two different types of BoNTs (types A and B), respectively. The corresponding limits of detection (LODs) were determined as 5.7 ng/mL (type A) and 1.3 ng/mL (type B). Total assay time, including that for immunoreaction, washing, and detection, was less than 2 h.

Although the diverse effects of ionizing radiation on biological and pathological processes at various levels ranging from molecular to whole body are well studied, the effects on adult stem cells by ionizing radiation remain largely unknown. In this study, we characterized the functional modifications of adult Drosophila midgut intestinal stem cells after ionizing radiation treatment. A dose of 10 Gy of radiation decreased the proliferative capacity of intestinal stem cells. Interestingly, after irradiation at 2 Gy, the intestinal stem cells exhibited increased proliferative activity, misdifferentiation and γH2AvD and 8-oxo-dG levels. In addition, the guts irradiated with 2 Gy showed increased JNK and AKT activities. Furthermore, we showed that 2 Gy of ionizing radiation induced centrosome amplification in intestinal stem cells of adult midguts. Our data gives molecular insights into the effects of ionizing radiation on functional modifications of stem cells. The adult Drosophila midgut intestinal stem cells offer a potentially rich new system for the exploration of the biological effects of ionizing radiation.

Lipoteichoic acid (LTA) and peptidoglycan (PGN) are considered as key virulence factors of Staphylococcus aureus , which is a representative sepsis-causing Gram-positive pathogen. However, cooperative effect of S. aureus LTA and PGN on nitric oxide (NO) production is still unclear despite the pivotal roles of NO in initiation and progression of sepsis. We here evaluated the cooperative effects of S. aureus LTA (SaLTA) and muramyl dipeptide (MDP), the minimal structure of PGN, on NO production in both a mouse macrophage-like cell line, RAW 264.7 and mouse bone marrow-derived macrophages (BMMs). Although MDP alone did not affect NO production, MDP potently enhanced SaLTA-induced NO production via the expression of inducible NO synthases. The enhanced NO production was ameliorated in BMMs from TLR2-, CD14-, MyD88-, and NOD2-deficient mice. Moreover, the augmented SaLTA-induced NO production by MDP was attenuated by inhibitors specific for PAFR and MAP kinases. Furthermore, MDP also potently increased SaLTA-induced activities of STAT1, NF-κB, and AP-1 transcription factors, and specific inhibitors for these transcription factors suppressed the elevated NO production. Collectively, these results demonstrated that MDP potentiates SaLTA-induced NO production via TLR2/NOD2/PAFR, MAP kinases signaling axis, resulting in the activation of NF-κB, AP-1 and STAT1 transcription factors.

Background Bacillus ancthracis causes cutaneous, pulmonary, or gastrointestinal forms of anthrax . B. anthracis is a pathogenic bacterium that is potentially to be used in bioterrorism because it can be produced in the form of spores. Currently, protective antigen (PA)-based vaccines are being used for the prevention of anthrax, but it is necessary to develop more safe and effective vaccines due to their prolonged immunization schedules and adverse reactions. Methods We selected the lipoprotein GBAA0190, a potent inducer of host immune response, present in anthrax spores as a novel potential vaccine candidate. Then, we evaluated its immune-stimulating activity in the bone marrow-derived macrophages (BMDMs) using enzyme-linked immunosorbent assay (ELISA) and Western blot analysis. Protective efficacy of GBAA0190 was evaluated in the guinea pig (GP) model. Results The recombinant GBAA0190 (r0190) protein induced the expression of various inflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and macrophage inflammatory protein-1α (MIP-1α) in the BMDMs. These immune responses were mediated through toll-like receptor 1/2 via activation of mitogen-activated protein (MAP) kinase and Nuclear factor-κB (NF-κB) pathways. We demonstrated that not only immunization of r0190 alone, but also combined immunization with r0190 and recombinant PA showed significant protective efficacy against B. anthracis spore challenges in the GP model. Conclusions Our results suggest that r0190 may be a potential target for anthrax vaccine.

Muscle aging is closely related to unhealthy late-life and organismal aging. Recently, the state of differentiated cells was shown to be critical to tissue homeostasis. Thus, understanding how fully differentiated muscle cells age is required for ensuring healthy aging. Adult Drosophila muscle is a useful model for exploring the aging process of fully differentiated cells. In this study, we investigated age-related changes of γH2AX, an indicator of DNA strand breaks, in adult Drosophila muscle to document whether its changes are correlated with muscle degeneration and lifespan. The results demonstrate that γH2AX accumulation increases in adult Drosophila thoracic and leg muscles with age. Analyses of short-, normal-, and long-lived strains indicate that the age-related increase of γH2AX is closely associated with the extent of muscle degeneration, cleaved caspase-3 and poly-ubiquitin aggregates, and longevity. Further analysis of muscle-specific knockdown of heterochromatin protein 1a revealed that the excessive γH2AX accumulation in thoracic and leg muscles induces accelerated degeneration and decreases longevity. These data suggest a strong correlation between age-related muscle damage and lifespan in Drosophila . Our findings indicate that γH2AX may be a reliable biomarker for assessing muscle aging in Drosophila .