많은 연구에 따르면 Tenebrio molitor은 유충 단계에서 플라스틱을 섭취할 수 있다고 보고되었다. 이 연구의 목적은 T. molitor 유충의 성장과 발달에 발포폴리스티렌 섭취가 미치는 영향을 조사하는 것이다. 밀기울을 섭취한 유충의 성장률은 발포폴리스티렌을 섭취한 유충의 성장률보다 더 좋았고(p < 0.001) 발포폴리스티렌을 섭취한 유 충의 번데기로 전환되는 기간은 밀기울을 섭취한 유충의 번데기로 전환되는 기간보다 더 빨랐다(p < 0.001). 하지만 두 처리구간 생존율은 유의미한 차이가 없었다(p = 0.786). 이 결과에 따르면 발포폴리스티렌을 섭취한 유충은 체중 감소와 짧은 발육기간이 특징이지만 생존하는 것에는 문제가 없었다. 따라서 우리는 T. molitor가 플라스틱 폐기물 의 지속 가능하고 친환경적인 제거를 위한 주요 자원이라는 결론을 내렸다.
One of the key challenges for the commercialization of carbon nanotube fibers (CNTFs) is their large-scale economic production. Among CNTF spinning methods, surfactant-based wet spinning is one of the promising techniques for mass producing CNTFs. Here, we investigated how the coagulation bath composition affects the spinnability and the properties of CNTFs in surfactant-based wet spinning. We used acetone, DMAc, ethanol, and IPA as coagulants and analyzed the relationship between coagulation bath composition and the properties of CNTFs in terms of kinetic and thermodynamic coagulation parameters. From a kinetic perspective, we found that a low mass transfer rate difference (MTRD) is favorable for wet spinning. Based on this finding, we mixed the coagulant bath with solvent in a proper ratio to reduce the MTRD, which generally improved the wet spinning. We also showed that the coagulation strength, a thermodynamic parameter, should be considered. We believe that our research can contribute to establishment of surfactant-based wet spinning of CNTFs.
Haemaphysalis longicornis는 사람과 동물에게 여러 심각한 병원체를 전달하는 주요 매개체로, 한반도에 널리 분포하고 있다. H. longicornis는 Rickettsia spp., Borrelia spp., Francisella spp., Coxiella spp., 그리고 중증열성혈소판 감소증후군 바이러스 (SFTS virus) 등을 매개하는 것으로 알려져 있다. 국내에 서식하는 H. longicornis의 미생물 군집과 관련된 연구는 많이 진행되지 않은 것으로 확인되었다. 이 연구는 한반도 내 다양한 지역에서 채집된 H. longicornis의 미생물군집 다양성을 지역별, 성장 단계 및 성별에 따라 분석하였다. 2019년 6월부터 7월까지 질병관리청 권역별기후변화매개체감시거점센터 16개 지역에서 채집한 H. longicornis의 16S rRNA 유전자 V3-V4 영역을 PCR로 증폭 후 Illumina MiSeq 플랫폼으로 시퀀싱하였다. Qiime2를 활용한 미생물 다양성 분석을 통해 총 46개의 샘플에서 1,754,418개의 non-chimeric reads를 얻었으며, 평균 126개 의 operating taxonmic unit (OTU) 을 식별하여 총 1,398개의 OTU를 확인하였다. 대부분의 지역에서 Coxiella spp.가 우점종으로 나타났으며, 특히 Coxiella endosymbiont는 가장 높은 우점도를 보이며, Coxiella burnetii와 계통 발생 학적으로 유사한 것으로 확인되었다. 이 연구를 통해 분석된 결과는 각 지역의 H. longicornis 미생물군집 데이터 베이스 구축에 활용되었으며, 이를 통해 지역별 미생물군집의 특이성을 식별할 수 있게 하였다. 이는 한반도의 H. longicornis에 의한 질병 전파 연구와 이를 통한 공중보건 개선에 기여할 것으로 기대된다.
금번 연구를 통해 외래산림해충 확산 분석 플랫폼 K-SDM (K-SDM)의 해충 분포 기능이 개발되었다. 해충 분포를 보여주는 기능은 2가지로 구현되며, 조사 자료를 바탕으로 현재 국내의 해충 분포를 나타내는 “외래산림 해충분포”기능과 데이터를 분석하여 예측되는 미래의 해충 분포를 제공하는 “외래산림해충예측”기능이 있다. “외래산림해충분포”는 조사자에 의해 현장에서 구축된 DB 현황을 지도상에 수치로 나타내며, 입력 기간, 해충 종 별로 구분이 가능하여 원하는 해충종의 분포를 선택하여 볼 수 있다. 지도 좌측에는 각 도별로 조사된 해충 개체수의 통계를 도표로 제공하여 수치상으로도 해충 분포를 파악할 수 있다. “외래산림해충예측”은 DB를 분석 하고 미래 기후 시나리오를 적용하여 도출한 미래의 해충 예측 분포도를 사용자에게 제공되며, 미리보기 이미지 와 함께 원본자료가 첨부되어 좀 더 자세한 정보를 열람할 수 있다. 본 플랫폼의 해충 분포 기능은 최근 기후변화 등으로 외래산림해충의 발생이 증가하는 추세에 맞춰 이들의 현재 분포와 미래의 분포양상을 조기 파악하여 이를 통한 추후 조기 방제 및 대응책 마련 등에 크게 기여할 것으로 기대된다.
최근 국내에서는 꿀벌 대량소실 현상이 2022년부터 전국적으로 발생하고 있다. 우리나라 뿐 만 아니라, 전세계 적으로 양봉산업에 큰 위협이 되고 있는 봉군붕괴현상은 2016년 미국에서 세계 최초로 보고되었다. 국내에서는 2022년 민관 합동조사 결과, 이상기온, 응애, 말벌 등이 주요 원인으로 지목되었다. 대량소실 현상을 보인 양봉농 가와 정상 농가의 병원체 검출 비교 결과, 유의성있게 검출이 증가되는 병원체는 발견되지 않았다. 그러나, Tyrophagus mite, Trypanosome, Lake Sinai virus, Apis mellifera filamentous virus 등의 신종 응애, 원충 및 바이러 스 감염이 추가로 확인되었다. 국내에서 새롭게 감염이 확인된 기생충과 병원체가 대량소실, 나아가 봉군붕괴현 상에 직간접적으로 영향을 주었을 것으로 사료되며, 지속적인 조사와 연구개발을 통해 기후등 환경변화에 따른 신종 질병 검색과 대책을 마련해야 할 것이다.
Nanostructured ZnO materials have been studied extensively because of their functional properties. This paper presents a composite material of zinc oxide quantum dots (ZnO QDs) and porous carbon using a one-step carbonization process. The direct carbonization of a metal–organic complex generates mesostructured porous carbon with a homogeneous distribution of ZnO QDs. The structural and morphological properties are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The resulting ZnO QDs@porous carbon composite delivers a high specific capacity of 990 mAh g−1 at 100 mA g−1, 357 mAh g−1 at 2 A g−1, and high reversibility when evaluated as an anode for lithium ion batteries.
We report the discovery of a giant exoplanet in the microlensing event OGLE-2017-BLG-1049, with a planet―host star mass ratio of q = 9.53 ± 0.39 × 10-3 and a caustic crossing feature in Korea Microlensing Telescope Network (KMTNet) observations. The caustic crossing feature yields an angular Einstein radius of θE = 0.52 ± 0.11 mas. However, the microlens parallax is not measured because the time scale of the event, tE ≃ 29 days, is too short. Thus, we perform a Bayesian analysis to estimate physical quantities of the lens system. We find that the lens system has a star with mass Mh = 0.55+0.36 -0.29 M⊙ hosting a giant planet with Mp = 5.53+3.62 -2.87 MJup, at a distance of DL = 5.67+1.11 -1.52 kpc. The projected star{planet separation is aㅗ = 3.92+1.10 -1.32 au. This means that the planet is located beyond the snow line of the host. The relative lens{source proper motion is μrel ~ 7 mas yr-1, thus the lens and source will be separated from each other within 10 years. After this, it will be possible to measure the flux of the host star with 30 meter class telescopes and to determine its mass.
In this study, epoxy composites were reinforced with multi-walled carbon nanotubes and fused silica particles, dispersing the fillers within the epoxy resin based on a simple physical method using only shear mixing and ultrasonication. The hybrid composite specimens with 0.6 wt% of carbon nanotubes and 50 wt% of silica particles showed improved mechanical properties, with increase in tensile strength and Young’s modulus up to 12 and 37%, respectively, with respect to those of the baseline specimens. The experimental results showed that the low thermal expansion of the silica particles improved the thermal stability of the composites compared with that of the baseline specimen, whereas the thermal expansion slightly increased, due to the increased heat transfer from the exterior to the interior of specimens by the carbon nanotube filler. The coefficient of thermal expansion of the hybrid composite specimen reinforced with 0.6 wt% of carbon nanotubes and 50 wt% of silica particles was decreased by 25%, and the thermal conductivity was increased by about 84%, compared with those of the baseline specimen.
We studied the infection rate of and various metacercariocidal approaches to controlling Gymnophalloides seoi for prevention of human infection in cultured and natural oysters in Korea. The selected survey areas were Aphae-do (Shinan-gun, Jeollanam-do), which is an endemic area for G. seoi, and Tongyeong (Geonsangnam-do), which is the main production area of oysters in Korea. In the Tongyeong area, the metacercariae of G. seoi were not detected in cultured oysters (0/201) or wild oysters (0/134). Seventy-two G. seoi metacercariae were observed in 33 of 265 natural oysters collected from Aphae-do; however, metacercariae were not detected in the cultured oysters (0/1101) purchased from the Daejeon Fish Market. To investigate the viability of G. seoi metacercariae, various metacercariocidal treatments were used with 3.5% saline and oyster juice used as positive controls. The metacercariae survived for 75.4 h in 3.5% saline and 112.6 h in oyster juice. After the metacercariocidal treatment, G. seoi metacercariae were survived for 13.29 min in tap water, < 20 sec in 4.3% vinegar, no effect in a rinse of the whole oyster body in 70°C water for 1 sec, but 1 sec in a rinse of the whole oyster body in 90°C water for 1 sec. The greatest metacercariocidal effect on G. seoi was from rinsing oysters in 90°C water followed by those from treatment with 20% ethyl alcohol, 4.3% vinegar, and tap water. However, we suggest that the most actual prevention to G. seoi human infection is rinsing the oysters with tap water for at least 30 min.
Chamaecyparis obtusa is one of the economical conifers planted in Korea due to its good quality timber and wood characteristics. Individuals of C. obtusa containing high terpenes (HT) and low terpenes (LT) were selected for by colorimetric method. The HT of C. obtusa was delayed in wilting against various abiotic stresses compared to the LT plants. The HT group exposed to UV did not significant influence the chlorophyll content, and the chlorophyll value was higher in the HT group than the LT group. Also, chilling treatment (5℃) did not significant influence on the chlorophyll content. However treatment at -4℃ showed relatively low chlorophyll content in the LT group than the HT group. Plants exposure to high temperature was not a difference between the HT and the LT group. However, treatment at 38℃ influenced the chlorophyll content that was increased exposure time-dependently. In salt treatments, chlorophyll in the HT group was lower at high concentrations (300 and 500 mM) of NaCl. However, chlorophyll content increased to slightly in treatment time-dependently, which is 6.7% to 40%. H2O2 treatment has been a negative effect on the chlorophyll content in the HT group. All concentration of H2O2 decreased the chlorophyll content of 5% to 35%. Plants containing high terpenoids were resisted against some abiotic stress such as salt and H2O2. Our results implied that terpenoids could cause various abiotic stress resistance. These results could be utilized for efficient management and biomass production during forest silvicultures.
The present study was conducted to evaluate the effects of high levels of nutrients on the growth performance, blood metabolites and carcass characteristics of Hanwoo cattle. Eighteen Hanwoo steers were fed two types of diets: 1) Nine animals were fed the conventional diet including typical levels of crude protein (CP) and total digestive nutrients (TDN), and 2) Nine animals were fed the treatment diet including high levels of CP and TDN. The average body weight (BW) and dry matter intake (DMI) were greater (P < 0.05) in the treatment group than in the conventional group at early and late fattening stages. Also, in the treatment group, the average daily gain (ADG) was greater (P < 0.05) at the late fattening stage. The serum total lipid and cholesterol levels were higher (P < 0.05) in the late fattening stage of treatment group. The carcass weight, total fat weight, longissimus muscle area and the grade of meat quality were also greater (P < 0.05) in the treatment group than the conventional diet group. This study demonstrates that high levels of CP and TDN exhibit a positive effect on the growth performance and carcass characteristics, indicating that high levels of CP and TDN can be used as a cost-effective feeding program for Hanwoo cattle by shortening the feeding period.