• 대한화학회지
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• 제48권1호
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• pp.28-32
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• 2004

초임계 이산화탄소 용매에서의 (벤질렌)삼페닐 인 일리드 화합물의 카르보닐 화합물과의 Wittig 반응을 연구하였다. 소량의 조용매 (THF, 5%)를 첨가한 이산화탄소 (24 mL 용기)에 녹인 (벤질렌)삼페닐 인 일리드 (약 1 mmol)를 여러 방향족 알데히드와 초임계 조건(80 $^{\circ}C$, 2,000 psi) 에서 2시간 반응시켜 올레핀 화합물을 좋은 수율로 얻을 수 있었다. 새로운 조건에서의 반응은 기존 용매 (THF)에서의 반응보다는 약간 느리게 나타났으나 생성물의 (E)- 와 (Z)-이성체 비율에 차이가 있었다. 두 이성체가 함께 생성되는 반응의 경우 (Z)-이성체의 비율이 증가하였다. 반면 t-butylcyclohexanone과 같은 케톤과의 반응은 두 조건에서 모두 낮은 전환을 보였다. 이 연구를 통하여 이산화탄소에서의 Wittig 반응이 초임계 조건에서 좋은 수율로 이루어지며 이 새로운 용매의 사용으로 반응선택성의 변화가 가능할 수 있다는 초기 결과를 얻었다. 이 결과는 Wittig 반응과 같은 유용한 유기반응을 친환경 용매 (이산화탄소)에서 수행할 수 있도록 전환하는데 좋은 자료가 될 수 있다고 본다.

• 한국결정성장학회지
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• 제8권3호
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• pp.508-512
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• 1998

마이크로파(2.45GHz) 에너지를 이용한 소결법으로 $1100^{\circ}C$~$1300^{\circ}C$의 온도범위에서 반도체 세라믹스인 $Mn_3O_4{\cdot}Co_3O_4{\cdot}3NiO$ 조성의 NTC 서미스터를 소결하였으며, 그 전기적 특성을 조사하였다. 소결온도가 높아질수록 소결밀도가 높은 치밀한 소결체를 얻을 수 있었으며, 25~$85^{\circ}C$ 범위의 온도변화에 따른 전기저항변화 특성으로부터 구한 비저항 $B_{25^{\circ/85^{\circ}}$ 정수는 3100~3200K이었다. 마이크로파 하이브리드, 소결법으로 소결된 시편과 일반소결법으로 소결된 시편을 비교하면 소결특성과 전기적물성에서 비슷한 결과를 얻을 수 있었다. 마이크로파 에너지를 이용한 소결공정은 20분 안에 완료되는 짧은 시간의 급속소결법으로 공정 시간과 에너지를 크게 절감할 수 있었다.

• Journal of Ginseng Research
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• 제44권3호
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• pp.435-441
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• 2020

Background: As a process of aging, skeletal muscle mass and function gradually decrease. It is reported that ginsenoside Rb1 and Rb2 play a role as AMP-activated protein kinase activator, resulting in regulating glucose homeostasis, and Rb1 reduces oxidative stress in aged skeletal muscles through activating the phosphatidylinositol 3-kinase/Akt/Nrf2 pathway. We examined the effects of Rb1 and Rb2 on differentiation of the muscle stem cells and myotube formation. Methods: C2C12 myoblasts treated with Rb1 and/or Rb2 were differentiated and induced to myotube formation, followed by immunoblotting for myogenic marker proteins, such as myosin heavy chain, MyoD, and myogenin, or immunostaining for myosin heavy chain or immunoprecipitation analysis for heterodimerization of MyoD/E-proteins. Results: Rb1 and Rb2 enhanced myoblast differentiation through accelerating MyoD/E-protein heterodimerization and increased myotube hypertrophy, accompanied by activation of Akt/mammalian target of rapamycin signaling. In addition, Rb1 and Rb2 induced the MyoD-mediated transdifferentiation of the rhabdomyosarcoma cells into myoblasts. Furthermore, co-treatment with Rb1 and Rb2 had synergistically enhanced myoblast differentiation through Akt activation. Conclusion: Rb1 and Rb2 upregulate myotube growth and myogenic differentiation through activating Akt/mammalian target of rapamycin signaling and inducing myogenic conversion of fibroblasts. Thus, our first finding indicates that Rb1 and Rb2 have strong potential as a helpful remedy to prevent and treat muscle atrophy, such as age-related muscular dystrophy.

• 한국축산식품학회지
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• 제37권5호
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• pp.735-742
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• 2017

This study was conducted to isolate and characterize Paenibacillus sp. MBT213 possessing ${\beta}$-glucosidase activity from raw milk, and examine the enzymatic capacity on the hydrolysis of a major ginsenoside ($Rb_1$). Strain MBT213 was found to have a high hydrolytic ability on ginsenoside $Rb_1$ by Esculin Iron Agar test. 16S rDNA analysis revealed that MBT213 was Paenibacillu sp. Crude enzyme of MBT213 strain exhibited high conversion capacity on ginsenoside $Rb_1$ into ginsenoside Rd proven by TLC and HPLC analyses. The API ZYM kit confirmed that Paenibacillu sp. MBT213 exerted higher ${\beta}$-glucosidase and ${\beta}$-galactosidase activity than other strains. Optimum pH and temperature for crude enzyme were found at 7.0 and $35^{\circ}C$ in hydrolysis of ginsenoside $Rb_1$. After 10 d of optimal reaction conditions for the crude enzyme, ginsenoside $Rb_1$ fully converted to ginsenoside Rd. Ginseng roots (20%) were fermented for 14 d, and analyzed by HPLC showed that amount of ginsenoside $Rb_1$ significantly decreased, while that of ginsenoside Rd was significantly increased. The study confirmed that the ${\beta}$-glucosidase produced by Paenibacillus sp. MBT213 can hydrolyze the major ginsenoside $Rb_1$ and convert to Rd during fermentation of the ginseng. The ${\beta}$-glucosidase activity of this novel Paenibacillus sp. MBT213 strain may be utilized in development of variety of health foods, dairy foods and pharmaceutical products.

• Asian-Australasian Journal of Animal Sciences
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• 제29권10호
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• pp.1470-1476
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• 2016

Octacosanol, which has prominent physiological activities and functions, has been recognized as a potential growth promoter in animals. A total of 392 1-d-old male Arbor Acres broiler chicks with similar body weight were randomly distributed into four dietary groups of seven replicates with 14 birds each supplemented with 0, 12, 24, or 36 mg octacosanol (extracted from rice bran, purity >92%)/kg feed. The feeding trial lasted for six weeks and was divided into the starter (day 1 to 21) and the grower (day 22 to 42) phases. The results showed that the feed conversion ratio (FCR) was significantly improved in broilers fed a diet containing 24 mg/kg octacosanol compared with those fed the control diet in the overall phase (day 1 to 42, p = 0.042). The average daily gain and FCR both showed linear effects in response to dietary supplementation of octacosanol during the overall phase (p = 0.031 and 0.018, respectively). Broilers fed with 24 or 36 mg/kg octacosanol diet showed a higher eviscerated yield, which increased by 5.88% and 4.26% respectively, than those fed the control diet (p = 0.030). The breast muscle yield of broilers fed with 24 mg/kg octacosanol diet increased significantly by 12.15% compared with those fed the control diet (p = 0.047). Eviscerated and breast muscle yield increased linearly with the increase in dietary octacosanol supplementation (p = 0.013 and 0.021, respectively). Broilers fed with 24 or 36 mg/kg octacosanol diet had a greater (p = 0.021) $pH_{45min}$ value in the breast muscle, which was maintained linearly in response to dietary octacosanol supplementation (p = 0.003). There was a significant decrease (p = 0.007) in drip loss value between the octacosanol-added and the control groups. The drip loss showed linear (p = 0.004) and quadratic (p = 0.041) responses with dietary supplementation of octacosanol. These studies indicate that octacosanol is a potentially effective and safe feed additive which may improve feed efficiency and meat quality, and increase eviscerated and breast muscle yield, in broiler chicks. Dietary supplementation of octacosanol at 24 mg/kg diet is regarded as the recommended dosage in the broilers' diet.

• 한국전자파학회논문지
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• 제19권6호
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• pp.621-629
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• 2008

본 논문에서는 위성 탑재 부품의 중요한 요구 특성 중의 하나인 부품의 소형화를 위해 LTCC를 이용하여 Ka-대역 OBS 위성 중계기용 주파수 상향 변환기를 개발하였다. 주파수 상향 변환기 내에 적층으로 S-대역 저역통과 여파기와 K-대역 대역 통과 여파기를 배치 하였으며, 주파수 상향 변환 MMIC 혼합기를 조립 하였다. S-대역 저역 통과 여파기 설계에서는 수정된 엘립틱(Elliptic) 저역 통과 여파기 구조를 이용하여 임의의 주파수에 폴을 형성함으로써 임의의 스퓨리어스 신호를 선택적으로 제거할 수 있는 방법을 제시하였다. K-대역 대역 통과 여파기의 경우, 층간 커플링을 이용한 구조를 채택하였다. 주파수 상향 변환 혼합기에는 MMIC 이중 평형 다이오드 혼합기를 사용하였다. 제작된 LTCC 주파수 상향 변환기의 삽입 손실은 9 dB, 격리도는 51 dBc이며, 크기는 $8{\times}7{\times}0.6mm^3$로 기 개발된 Ka-대역 OBS 위성 중계기용 주파수 상향 변환기에 비해 1/3 크기의 소형화를 이룰 수 있었다.

• 한국식품영양과학회지
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• 제33권8호
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• pp.1343-1347
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• 2004

국내에서 시판 중인 요구르트의 CLA 함량과 상업용 dairy starter 유산균의 CLA 생산능을 조사하였다. 시판 요구르트 중의 CLA 함량은 4.1∼14.8 mg/100 g이었으며, 원료 우유사용비율이 낮아질수록 제품에 함유된 CLA 함량도 낮아지는 경향을 보였다. CLA 함량과 stearic acid, oleic acid, linoleic acid 및 linolenic acid의 함량, CLA 함량과 지방함량간에는 정의 상관관계를 보였다. 상업용 dairy starter 유산균 67균주 중 L. acidophilus 1종, L. casei 1종 및 Streptococcus thermophilus 3종 등 모두 5 균주가 기질로 첨가한 linoleic acid로부터 CLA를 생성하였다 또한 생성된 CLA는 cis-9, trans-11 이성체가 70% 이상으로 대부분을 차지하였다. 이들을 이용한 발효유는 대조구에 비해서 1.7∼2.6 mg/100 g의 CLA 함량의 증가를 보였으며, CLA 전환율은 6.1∼8.6%였다.

• Journal of Astronomy and Space Sciences
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• 제24권4호
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• pp.349-366
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• 2007

천체관측용 고효율 CCD 카메라 시스템과 제어소프트웨어의 독자개발의 시도로 KODAK사의 KAF-0401E($768\;{\times}\;512$), KAF-1602E($1536\;{\times}\;1024$), KAF-3200E($2184\;{\times}\;1472$) 등 세 종류의 CCD를 바꾸어 가며 장착할 수 있는 범용 CCD 카메라 시스템을 개발하였다. 기본적인 자료 입출력과 제어는 병렬 포트뿐만 아니라 입출력 속도가 상대적으로 바른 USB 포트로도 가능하도록 만들었다. ${\pm}18V$를 전원공급기로부터 공급받아 ${\pm}15V$와 +5V로 정류시켜서 시스템의 전원으로 사용하고 열전냉각소자 및 셔터는 ${\pm}12V$와 +5V로 동작되도록 하였다. 개발된 CCD 카메라는 전자회로기판을 2단으로 구성해서 공간 효율을 높였고, 전자회로의 구성은 컴퓨터에서 만들어진 클락 신호를 입력받아 CCD 동작을 위한 신호패턴을 만들어 주는 부분, CCD로부터 받은 신호를 증폭해서 디지털 신호로 바꿔주는 부분, 이 신호를 4비트씩 나누어서 병렬 포트에 전달하는 CCD 제어 부분과, 온도 센서의 신호를 디지털 신호로 바꾸어서 컴퓨터로 전달하는 온도제어 부분으로 이루어져 있다. 최대 냉각능력은 상온대비 ${\Delta}33^{\circ}C$이고, 이 온도 범위에서 약 $0.4^{\circ}C$의 정밀도로 제어 할 수 있다. 제작된 CCD 카메라 시스템의 읽기잡음은 $6e^-$이고, 이득은 $5e^-/ADU$이다. 모두 10대의 카메라가 만들어졌으며, CCD 카메라들은 작동시험에서 모두 만족한 결과를 얻었다.

• Journal of Ecology and Environment
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• 제44권3호
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• pp.126-142
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• 2020

Background: Most of the Pinus densiflora forests, occupying the largest area, have been restored in South Korea since the 1970s. As young pioneer forests, the succession process is under way. Since the forests are distributed nationwide and are vulnerable to disturbances, the process may differ depending on the geography and/or site conditions. Therefore, we reviewed the direction, the seral communities, and the late-successional species of progressive and disturbance-driven succession nationwide in the cool-temperate zone through meta-analysis and empirical observations. Main text: As a result of a meta-analysis of the direct succession and vertical structure, we found that the P. densiflora forest is in a directionally progressive succession, changing to the broadleaved forest after forming a mixed forest with its overwhelming successor, Quercus species (particularly Q. mongolica and Q. serrata). In dry stands in a relative sense, the Quercus species was favored occupying over 80% of the abundance of the succeeding species. Therefore, in dry stands, it is presumed that Quercus-dominated stage would last for a long time due to the current dominance and long life span, and eventually, it settles as Quercus-broadleaved forest with a site change. Contrary to this, it is presumed that in mesic stands where Quercus species do not occur or have low abundance, the late-successional broadleaved species settle early to form a co-dominant forest with multiple species. Due to geographical limits, the species composition of the two late-successional forests is different. Disturbances such as insect pests and fire retrogressed vulnerable P. densiflora forest for a while. However, it was mostly restored to the Quercus forest and is expected to be incorporated in the pathway of the dry stand. Conclusions: We revealed the succession process of P. densiflora forests according to geography and moisture and found that stand moisture had a decisive effect on the species and abundance of the successor. Although the P. densiflora forest is undergoing structural changes, the forest is still young; so within a few decades, physiognomy is not likely to change. Therefore, the decrease in the forest area may be due to other causes such as disturbances and forest conversion rather than due to succession.

• Asian-Australasian Journal of Animal Sciences
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• 제28권7호
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• pp.1006-1013
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• 2015

Heat-stress remains a costly issue for animal production, especially for poultry as they lack sweat glands, and alleviating heat-stress is necessary for ensuring animal production in hot environment. A high ${\gamma}$-aminobutyric acid (GABA)-producer Lactobacillus strain was used to investigate the effect of dietary GABA-producer on laying performance and egg quality in heat-stressed Hy-line brown hens. Hy-Line brown hens (n = 1,164) at 280 days of age were randomly divided into 4 groups based on the amount of freeze-dried GABA-producer added to the basal diet as follows: i) 0 mg/kg, ii) 25 mg/kg, iii) 50 mg/kg, and iv) 100 mg/kg. All hens were subjected to heat-stress treatment through maintaining the temperature and the relative humidity at $28.83{\pm}3.85^{\circ}C$ and 37% to 53.9%, respectively. During the experiment, laying rate, egg weight and feed intake of hens were recorded daily. At the 30th and 60th day after the start of the experiment, biochemical parameters, enzyme activity and immune activity in serum were measured. Egg production, average egg weight, average daily feed intake, feed conversion ratio and percentage of speckled egg, soft shell egg and misshaped egg were significantly improved (p<0.05) by the increasing supplementation of the dietary GABA-producer. Shape index, eggshell thickness, strength and weight were increased linearly with increasing GABA-producer supplementation. The level of calcium, phosphorus, glucose, total protein and albumin in serum of the hens fed GABA-producing strain supplemented diet was significantly higher (p<0.05) than that of the hens fed the basal diet, whereas cholesterol level was decreased. Compared with the basal diet, GABA-producer strain supplementation increased serum level of glutathione peroxidase (p = 0.009) and superoxide dismutase. In conclusion, GABA-producer played an important role in alleviating heat-stress, the isolated GABA-producer strain might be a potential natural and safe probiotic to use to improve laying performance and egg quality in heat-stressed hens.