The AlSi10Mg alloy has garnered significant attention for its application in laser powder bed fusion (L-PBF), due to its lightweight properties and good printability using L-PBF. However, the low production speed of the L-PBF process is the main bottleneck in the industrial commercialization of L-PBF AlSi10Mg alloy parts. Furthermore, while L-PBF AlSi10Mg alloy exhibits excellent mechanical properties, the properties are often over-specified compared to the target properties of parts traditionally fabricated by casting. To accelerate production speed in L-PBF, this study investigated the effects of process parameters on the build rate and mechanical properties of the AlSi10Mg alloy. Guidelines are proposed for high-speed additive manufacturing of the AlSi10Mg alloy for use in automotive parts. The results show a significant increase in the build rate, exceeding the conventional build rate by a factor of 3.6 times or more, while the L-PBF AlSi10Mg alloy met the specifications for automotive prototype parts. This strategy can be expected to offer significant cost advantages while maintaining acceptable mechanical properties of topology-optimized parts used in the automobile industry.

The emergence of ferrous-medium entropy alloys (FeMEAs) with excellent tensile properties represents a potential direction for designing alloys based on metastable engineering. In this study, an FeMEA is successfully fabricated using laser powder bed fusion (LPBF), a metal additive manufacturing technology. Tensile tests are conducted on the LPBF-processed FeMEA at room temperature and cryogenic temperatures (77 K). At 77 K, the LPBF-processed FeMEA exhibits high yield strength and excellent ultimate tensile strength through active deformation-induced martensitic transformation. Furthermore, due to the low stability of the face-centered cubic (FCC) phase of the LPBFprocessed FeMEA based on nano-scale solute heterogeneity, stress-induced martensitic transformation occurs, accompanied by the appearance of a yield point phenomenon during cryogenic tensile deformation. This study elucidates the origin of the yield point phenomenon and deformation behavior of the FeMEA at 77 K.

해충방제용 미생물 선발을 위해 2018년도에 공원·산림·유기농 근권 토양 87지점을 수집하여 갈색거저리를 이용한 insect-bait법 및 자연조건에서의 감염사충으로부터 곤충병원성 곰팡이를 132균주 분리하였다. 분리된 균주는 점박이응 애, 복숭아혹진딧물에 대한 살충활성 스크리닝을 통하여 각 해충별 살충활성을 보이는 56균주를 선발하였다. 선발된 균주들은 rDNA의 ITS영역을 이용하여 분류동정 하였다. 추가 적용범위 확대를 위해 무잎벌(종령 유충), 거세미나방류 (3~6령 유충)와 같은 지하부 이동성 해충의 방제 가능성을 탐색하기 위해 선발 곤층병원성 곰팡이의 포자 현탁액의 관주처리 방법으로 살충활성을 검정 중이다.

Spotted wing drosophila (SWD), Drosophila suzukii (Diptera: Drosophilidae), is an important quarantine insect pest on blueberry and strawberry exportation in Korea. Due to IPPC recommendations of replacement of methyl bromide (MB) and recent critical issue about its chronic inhalation toxicity to fumigator and related workers along with post-fumigation, alternatives to MB is urgently required. Thus, we evaluated efficacies of ethyl formate (EF) to SWD eggs using two different bioassay methods; using eggs oviposited on artificial diet and on blueberries naturally infested with SWD adults. In results, there was no differences between two bioassay methods in terms of LCT99 value of EF.

Ethyl formate (EF) fumigation under green house condition is a new concept. Its concentrations inside and surrounding of the glass house (GH) and vinyl house (VH) were evaluated for 4 h (during daytime) and 12 h (during nighttime) after fumigation along with the evaluation of post-fumigation EF concentrations. The cumulative EF concentration × time (Ct) value of the 6 sampling positions in VH were 22.67 and 17.53 g·h/m3, respectively for day and night fumigation, which were 2.62 and 4.53 g·h/m3 respectively for day and night application in GH. The EF level (PPM) outside the VH and GH as well as after 20-min post fumigation were < 50 ppm revealing its safety level as its’ threshold limit value (TLV) is 100 ppm. The new technology using liquid EF fomulation could be a key option in smart-farm technologies in future. (Supported by PJ0133562018, RDA)

경기지역에 발생하는 돌발 및 남방계 해충의 발생실태 조사결과, 겨울철 경기지역 평균기온이 전년보다 3.7℃, 평년보다는 1.2℃ 낮게 경과함에 따라 포도 재배지 꽃매미 평균 월동난 부화율은 35.6%로 전년 대비 60% 감소하였음. 블루베리 재배지 갈색날개매미충의 평균 월동난 부화율은 26.9%로 전년 대비 50% 감소하였으며, 겨울철 피해가지 제거로 부화약충의 밀도는 매우 낮았음. 저온 적응성이 강한 미국선녀벌레의 경우 6월 중순 안성지역 평야 블루베리에서 약충이 가지당 최대 6.64마리 발견되었으나, 하절기 고온 등으로 성충의 밀도는 크게 감소되었음. 남방계 해충인 볼록총채벌레는 포도 재배지에서 5월 하순부터 발견되기 시작하여 7월 상순부터 급격히 증가하는 양상을 보인 가운데 지역별로는 남부지역(안성), 지대별로는 중산간지 > 산간지 > 평야지 순으로 높은 경향을 보였음.

The current protocols of methyl bromide (MeBr) fumigation on imported nursery plants, which are seriously infested with quarantine mealy bugs and scales, could be reevaluated because there were no limited uses of loading ratio, packing types etc. Another emerging issues is that the workplace health issues on MeBr fumigation are related with poor ventilation etc as well as well-known phytotoxic damages on them. In previous report, we have evaluated the efficacies of ethyl formate (EF) and phosphine (PH3) on different types of mealybugs. Herein, the phytotoxic damages of EF and PH3 on Alocasia, Sansevieria, Cactaceae and Croton genera were evaluated in terms of chlorophyll contents, color changes etc. This study showed that EF and PH3 fumigation on imported plants could be applicable to replacement of MeBr with further confirmation trials.

Ethyl formate (EF) and methyl salicylate (MS) are naturally occurring and generally safe substances for use. Sub-lethaldoses of EF and MS were evaluated to find synergistic fumigation action against azuki bean beetle (ABB), Callosobruchuschinensis (L.). Susceptibility of the ABB to EF was in the order of eggs =adults >larvae >pupae. Adults was most sensitiveto MS, and followed by eggs. Larvae and pupae were highly tolerant to MS. However, in synergistic effects of EF andMS showed that all the stages of ABB were highly sensitive in the order of adults >eggs >larvae >pupae. Highest synergisticratio was found against adults when using LC10 of both EF and MS as compared to other stages. Notably, MS synergizedthe EF exposure to all stages of ABB. This finding paves the way to exploiting synergistic activity of MS and EF againstABB for the safeguard of stored azuki bean grains.

To determine sugars content of agricultural products and foods, simultaneous quantitative analysis was carried out on fructose, glucose, sucrose, maltose, and lactose by HPLC-RI. Analysis conditions were set as column ZORBAX carbohydrate (4.6 mm ID×250 mm, 5 μm), the mobile phase of 75% ACN, the column temperature of 35oC, sample injection amount of 10 μL and the flow rate of 1 mL/min. Five standard solutions were isolated without interfering peak within 30 minutes and the calibration curves of standard were confirmed excellent linearity from 0.10% to 1.00% with R2≥0.999. Based on the chromatogram of the standard solution, the limit of quantification (LOQ) and the limit of detection (LOD) values were calculated. The accuracy of the analytical values were highest at 100% water extraction method to the fructose 95.7%, sucrose 98.7%, lactose 102.7% respectively, compared with reference value of a certified reference material (BCR644), by applying the four solvent extraction methods. Using an in-house quality control material (infant formula), repeatability and reproducibility values of this experiment were verified on the basis of AOAC guideline and reference values were set up at 1.17 g/100g of glucose, 0.85 g/100g of maltose, and 45.54 g/100g of lactose. Quality control charts were drawn up and used for sugars analysis of agricultural products.

Graphene was grown on molybdenum (Mo) foil by a chemical vapor deposition method at different growth temperatures (1000°C, 1100°C, and 1200°C). The properties of graphene were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy, and Raman spectroscopy. The results showed that the quality of the deposited graphene layer was affected by the growth temperature. XRD results showed the presence of a carbide phase on the Mo surface; the presence of carbide was more intense at 1200°C. Additionally, a higher I2D/IG ratio (0.418) was observed at 1200°C, which implies that there are fewer graphene layers at this temperature. The lowest ID/IG ratio (0.908) for the graphene layers was obtained at 1200°C, suggesting that graphene had fewer defects at this temperature. The size of the graphene domains was also calculated. We found that by increasing the growth temperature, the graphene domain size also increased.

Traditionally, Centella asiatica leaf extracts are used to treat neurodegenerative diseases in India. Centella asiatica is reportedly used to enhance memory and treat dementia, but its promoting effect on neural stem cell differentiation has not been studied yet. In the present study, we investigated whether or not Centella asiatica leaf extracts act on neuronal precursor cells and neuronal cell lines to induce neuronal differentiation, neurite outgrowth, and neuroprotection. The neurogenesis-promoting potential of Centella asiatica leaf extracts was determined by differentiation assay on neural stem cells isolated from mouse embryos and PC12 cell lines. To understand the contribution of specific neural cell types towards increase after Centella asiatica treatment, neural stem cells were differentiated into various neural subtypes and checked by Western blotting using neural cell lineage-specific antibody markers. Neuroprotective activity of Centella asiatica was analyzed in PC12 cells exposed to 100 μM of H2O2. Cell growth was analyzed by MTT assay while cell death was analyzed by Western blotting detection of apoptosis-related proteins. Cells treated with Centella asiatica had significantly longer primary and secondary neurites as well as a higher number of neurites per cell compared to control cells. Expression levels of TUBBIII, TH, NF, and BDNF increased upon Centella asiatica treatment, suggesting that Centella asiatica has a neurogenesis-promoting effect. Centella asiatica also inhibited oxidative stress-induced neural cell damage through regulation of apoptosis- and cell cycle-related proteins. Thus, leaf extracts of Centella asiatica might promote neurogenesis, neuroregeneration, and neuroprotection in the context of neurodegenerative diseases.

The oocyte undergoes various events during maturation and requires many substances for the maturation process. Various intracellular organelles are also involved in maturation of the oocyte. During the process glucose is essential for nuclear and cytoplasmic maturation, and adenosine triphosphate is needed for reorganization of the organelles and cytoskeleton. If mitochondrial function is lost, several developmental defects in meiotic chromosome segregation and maturation cause fertilization failure. The endoplasmic reticulum, a store for Ca2+, releases Ca2+ into the cytoplasm in response to various cellular signaling molecules. This event stimulates secretion of hormones, growth factors and antioxidants in oocyte during maturation. Also, oocyte nuclear maturation is stimulated by growth factors such as epidermal growth factor. This review summarizes roles of organelles with focus on the Golgi apparatus during maturation in oocyte.