본 연구는 제주도 모슬포 해역에서 채집된 대형 포식성 복족류인 붉은입두꺼비고둥(Tutufa bufo) 두 개체를 대상 으로 테트로도톡신(TTX) 존재 여부를 조사하였다. 일본에 서 채집된 붉은입두꺼비고둥의 내장에서 TTX가 검출된 사례가 보고된 바 있으며, 최근 제주도 남부 해역에서 해 당 종이 혼획되고 있으나, 한국 해역에 분포하는 붉은입 두꺼비고둥의 TTX 축적에 대한 정보는 부족하다. 이에 본 연구에서는 경쟁적 효소면역분석법(cELISA) 을 사용하여 붉은입두꺼비고둥의 주요 연조직(전타액선, 구강부, 소화 선, 생식소, 아가미, 신장, 근육, 후타액선)을 분석하였다. 분석 결과, 모든 조직에서 TTX 농도는 검출 한계 미만으 로 나타났다. 그러나 TTX 축적에는 개체 간, 지역적, 계 절적 변동 가능성이 존재할 수 있으므로, 한국 해역에서 붉은입두꺼비고둥의 TTX 축적 위험을 정확하게 평가하기 위해서는 추가적인 시료 확보와 계절별 연구가 요구된다.

본 연구에서는 국내산 양식 자주복의 테트로도톡신 및 그 유사체를 UHPLC-QqQ MS를 이용하여 분석하였다. 테 트로도톡신 분석법의 직선성과 일내 및 일간 정확도와 정 밀성, 검출 한계, 정량 한계를 구한 결과 CODEX 가이드라 인 기준에 적합하였다. 국내산 양식 자주복의 부위별 테트 로도톡신 함량을 분석한 결과 일부 시료의 간과 근육 부위 를 제외한 대부분의 시료에서 테트로도톡신이 검출되지 않 았으며, 검출된 시료도 간과 근육 부위에서는 각각 0.07 mg/ kg, 0.06 mg/kg의 낮은 농도로 테트로도톡신이 검출되었다. 테트로도톡신 유사체의 경우 국내산 양식 자주복에서 dideoxyTTX, trideoxyTTX, norTTX가 검출되었다. 이 중 dideoxyTTX는 국내산 양식 자주복의 모든 부위에서 주요 테트로도톡신 유사체로 확인되었다. 본 연구를 통해 국내산 양식 자주복의 테트로도톡신 및 그 유사체 분포를 이해 하는데 도움을 줄 수 있으며 국내 해양생물 독소 데이터베 이스 구축에 기여할 수 있을 것으로 사료된다.

본 연구에서는 국내산 검복의 테트로도톡신 및 그 유사체 를 UHPLC-QqQ MS를 이용하여 분석하였다. 테트로도톡신 분석법의 직선성, 검출 한계, 정량 한계, 정확성 및 정밀성을 확인한 뒤 국내산 검복의 부위별 테트로도톡신 함량을 분석 한 결과 대부분의 시료에서 테트로도톡신이 검출되었으며 정 소를 제외한 모든 부위에서 테트로도톡신이 검출되었다. 검 복의 테트로도톡신 함량은 난소에서 0.27-67.7mg/kg으로 가 장 높았으며 껍질과 간에서도 가식 부위인 정소와 근육에 비 해 높은 농도의 테트로도톡신이 검출되었다. 테트로도톡신 유 사체의 경우, 국내산 검복에서 4,9-anhydroTTX, deoxyTTX, dideoxyTTX, trideoxyTTX, norTTX가 검출되었으며 이 중 trideoxyTTX는 국내산 검복의 모든 부위에서 주요 테트로도 톡신 유사체로 확인되었다. 본 연구를 통해 국내산 검복의 테 트로도톡신 및 그 유사체 함량 및 조성을 이해하고, 국내 해 양생물 독소 연구에 해당정보가 활용될 수 있을 것으로 기대된다.

Today, the principles of green chemistry are being fundamentally applied in the chemical industry, such as the nitrobenzene industry, which is an essential intermediate for various commercial products. Research on the application of response surface methodology (RSM) to optimize nitrobenzene synthesis was conducted using a sulfated silica (SO4/SiO2) catalyst and batch microwave reactor. The nitrobenzene synthesis process was carried out according to RSM using a central composite design (CCD) design for three independent variables, consisting of sulfuric acid concentration on the silica (%), stirring time (min), and reaction temperature (°C), and the response variable of nitrobenzene yield (%). The results showed that a three-factorial design using the response surface method could determine the optimum conditions for obtaining nitrobenzene products in a batch microwave reactor. The optimum condition for a nitrobenzene yield of 63.38 % can be obtained at a sulfuric acid concentration on the silica of 91.20 %, stirring time of 140.45 min, and reaction temperature of 58.14 °C. From the 20 experiments conducted, the SO4/SiO2 catalyst showed a selectivity of 100 %, which means that this solid acid catalyst can potentially work well in converting benzene to nitrobenzene.

Graphene-based materials modified with transition metals, and their potential utilization as hydrogen storage devices, are extensively studied in the last decades. Despite this widespread interest, a comprehensive understanding of the intricate interplay between graphene-based transition metal systems and H2 molecules remains incomplete. Beyond fundamental H2 adsorption, the activation of H2 molecule, crucial for catalytic reactions and hydrogenation processes, may occur on the transition metal center. In this study, binding modes of H2 molecules on the circumcoronene (CC) decorated with Cr or Fe atoms are investigated using the DFT methods. Side-on (η2-dihydrogen bond), end-on and dissociation modes of H2 binding are explored for high (HS) and low (LS) spin states. Spin state energetics, reaction energies, QTAIM and DOS analysis are considered. Our findings revealed that CC decorated with Cr (CC-Cr) emerges as a promising material for H2 storage, with the capacity to store up to three H2 molecules on a single Cr atom. End-on interaction in HS is preferred for the first two H2 molecules bound to CC-Cr, while the side-on LS is favored for three H2 molecules. In contrast, CC decorated with Fe (CC-Fe) demonstrates the capability to activate H2 through H–H bond cleavage, a process unaffected by the presence of other H2 molecules in the vicinity of the Fe atom, exclusively favoring the HS state. In summary, our study sheds light on the intriguing binding and activation properties of H2 molecules on graphene-based transition metal systems, offering valuable insights into their potential applications in hydrogen storage and catalysis.

In this paper, iron ore tailings (IOT) were separated from the tailings field and used to prepare cement stabilized macadam (CSM) with porous basalt aggregate. First, the basic properties of the raw materials were studied. Porous basalt was replaced by IOT at ratios of 0, 20 %, 40 %, 60 %, 80 %, and 100 % as fine aggregate to prepare CSM, and the effects of different cement dosage (4 %, 5 %, 6 %) on CSM performance were also investigated. CSM’s durability and mechanical performance with ages of 7 d, 28 d, and 90 d were studied with the unconfined compression strength test, splitting tensile strength test, compressive modulus test and freeze-thaw test, respectively. The changes in Ca2+ content in CSM of different ages and different IOT ratios were analyzed by the ethylene diamine tetraacetic acid (EDTA) titration method, and the micro-morphology of CSM with different ages and different IOT replaced ratio were observed by scanning electron microscopy (SEM). It was found that with the same cement dosage, the strengths of the IOT-replaced CSM were weaker than that of the porous basalt aggregate at early stage, and the strength was highest at the replaced ratio of 60 %. With a cement dosage of 4 %, the unconfined compressive strength of CSM without IOT was increased by 6.78 % at ages from 28 d to 90 d, while the splitting tensile strength increased by 7.89 %. However, once the IOT replaced ratio reached 100 %, the values increased by about 76.24 % and 17.78 %, which was better than 0 % IOT. The CSM-IOT performed better than the porous basalt CSM at 90 d age. This means IOT can replace porous basalt fine aggregate as a pavement base.

Background: In healthy dentin conditions, odontoblasts have an important role such as protection from invasion of pathogens. In mammalian teeth, progenitors such as mesenchymal stem cells (MSCs) can migrate and differentiate into odontoblast-like cells, leading to the formation of reparative dentin. For differentiation using stem cells, it is crucial to provide conditions similar to the complex and intricate in vivo environment. The purpose of this study was to evaluate the potential of differentiation into odonto/ osteoblasts, and compare co-culture with/without epithelial cells. Methods: MSCs and epithelial cells were successfully isolated from dental tissues. We investigated the influences of epithelial cells on the differentiation process of dental pulp stem cells into odonto/osteoblasts using co-culture systems. The differentiation potential with/without epithelial cells was analyzed for the expression of specific markers and calcium contents. Results: Differentiated odonto/osteoblast derived from dental pulp tissue-derived mesenchymal stem cells with/without epithelial cells were evaluated by qRT-PCR, immunostaining, calcium content, and ALP staining. The expression of odonto/ osteoblast-specific markers, calcium content, and ALP staining intensity were significantly increased in differentiated cells. Moreover, the odonto/osteogenic differentiation capacity with epithelial cells co-culture was significantly higher than without epithelial cells co-culture. Conclusions: These results suggest that odonto/osteogenic differentiation co-cultured with epithelial cells has a more efficient application.

The study aimed to investigate the impact of varying levels of neutral detergent-soluble fiber (NDSF) in Hanwoo growing cattle diets on rumen fermentation and methane (CH4) emissions. An in vitro rumen fermentation experiment utilized feeds with different NDSF levels, incorporating ingredients such as corn grain, soybean meal, soybean hulls, palm kernel meal, beet pulp and timothy hay. The NDSF contents in the diets were 9.02% (T1), 10.09% (T2), 12.42% (T3) and 14.63% (T4). In vitro dry matter digestibility (IVDMD) at 48 h was 7.4% higher for T4 compared to T1 (p<0.05). Total gas production at 48 h was 6.6% higher for T4 than T1 (p<0.05). CH4 production significantly decreased at 9 h and 12 h for T1 and T2 (p<0.05). At 48 h, CH4 production was 5.6% higher for T4 compared to T1 and 6.7% higher compared to T2 (p<0.05). At 12 h ans 24 h, the ammonia nitrogen concentration of T4 was approximately 33.1% and 40.4% lower, respectively, compared to T1 (p<0.05). The acetate to propionate ratio at 48 h was approximately 18.8% higher for T4 than T1 (p<0.05). From 9 h to 48 h, the proportions of butyrate and valerate were significantly higher for T4 (p<0.05). At 48 h, the dominant phylum in T4's rumen microbial community was Candidatus Thermoplasmatota Methanomassiliicoccus, an Archaea. Therefore, this study confirmed that increasing the NDSF content in growing Hanwoo cattle diets up to 12.42% increases IVDMD without increasing CH4 emissions, which is expected to positively impact Hanwoo productivity.

본 연구에서는 간담도 조영제를 사용하는 간 검사에 있어서 동맥기 검사에서의 원인 미상의 이유로 인하여 일시적 호흡곤란이 발생하고, 호흡정지가 실패하여 영상의 질을 저하하는 경우가 있는데, 이에 있어 기존의 고안된 여러 방법이 아닌 백신 기법을 사용하여 호흡정지의 성공률을 높이고 영상의 질을 향상해 임상의 유용성을 평가하고자 한다. 간 검사를 시행하는 65세 이상 또는 의사소통이 명확히 되는 간병증 환자 20명을 대상으로 진행하였으며, 동맥기 검사 직전에 백신 개념의 조영제 0.1 ml를 주입하여 환자 신체가 조영제에 적응하게 한 후, 조영제 9.9 ml를 주입하여 동맥기 검사를 진행하였다. 영상의학과 전문의 1명과 전문방사선사 4명이 영상을 평가하고, 환자로부터 조영제 주입 후의 신체적 평가를 직접 확인하였다. 그 결과로 정성적 평가인 5점 리커트 척도를 통하여 대응 표본 T-검정으로 유의한 차이가 있었고, 시행된 환자 본인에 있어서 조영제의 주입 시, 체감에 있어 대부분 느낌도 받을 수 없었으며, 환자의 조영제에 대한 두려움과 만족도 측면에서 약 3배 높은 결과를 보여주었다. 그리고 이에 대한 영향으로 영상 측면에서도 일시적 호흡곤란이 발생하지 않고 검사에 방해 요소가 줄어든바, 약 1.78배 높아진 평가 를 얻을 수 있었고 동맥기 검사에서 호흡정지 실패 발생 빈도가 줄어드는 것을 확인할 수 있었으며, 임상에서 높은 질의 영상을 얻을 수 있을 것이라 사료된다.

Gas identification techniques using pattern recognition methods were developed from four micro-electronic gas sensors for noxious gas mixture analysis. The target gases for the air quality monitoring inside vehicles were two exhaust gases, carbon monoxide (CO) and nitrogen oxides (NOx), and two odor gases, ammonia (NH3) and formaldehyde (HCHO). Four MEMS gas sensors with sensing materials of Pd-SnO2 for CO, In2O3 for NOX, Ru-WO3 for NH3, and hybridized SnO2-ZnO material for HCHO were fabricated. In six binary mixed gas systems with oxidizing and reducing gases, the gas sensing behaviors and the sensor responses of these methods were examined for the discrimination of gas species. The gas sensitivity data was extracted and their patterns were determined using principal component analysis (PCA) techniques. The PCA plot results showed good separation among the mixed gas systems, suggesting that the gas mixture tests for noxious gases and their mixtures could be well classified and discriminated changes.

Metal-free N–S- and N–P-doped nanocarbon (SCNP and PCNP) electrocatalysts prepared through sustainable microwaveassisted synthesis using hemigraphis alternata plant leaves. The prepared heteroatom-doped nanocarbon materials are active catalysts for the two-electron oxygen reduction reaction (ORR) to produce 65–70% of hydrogen peroxide. As evidenced from the XPS, most proportion of the doped heteroatoms contain the oxygen functional groups in the nanocarbons. These attributes are the critical factors to see the selective two-electron transfer ORR for the PCNP and SCNP. This approach shed light on the critical role of dual heteroatoms doping and the oxygen functionalities in nanocarbon towards the selectivity of ORR. We believe that this method would allow the preparation of heteroatom that contains oxygen functionalities. Our work paves a sustainable way of preparation of nanocarbon based ORR catalysts that are only selective for two-electron transfer process.

The most significant threat to the ecosystem is emerging pollutants, which are becoming worse each year and harming the planet severely and permanently. Many organic and inorganic contaminants are present and persistent due to various world events and population growth. As a result, there is a greater need for new technology and its application to address the problems caused by developing pollutants. Carbon composite nanomaterials have significant potential in the fight against numerous environmental contaminants due to their distinctive attributes. This review discusses the reports of customized carbon composite nanomaterials to meet the need for specific elimination of emerging contaminants. Physical and chemical features such as high surface area, conductivity (thermal and electrical), and vibroelectronic properties, size, shape, porosity, and composite nature are making these tailored materials of carbon-based nanomaterials an emerging and sustainable tool to remove persistent compounds like emerging contaminants in aqueous solution. Different composite materials are well discussed in this review, along with their adsorption efficiency of diverse emerging contaminants, including Bisphenol A, estradiol, metformin, etc. This review provides insight into the recent trends limited to 2017–2023. The limitations of carbon-based nanomaterials, such as regeneration and cost-effectiveness, have also been overcome in recent years by diverse modifications in the production process, which can be further improved to make these materials well suited for an extended group of emerging contaminants.