• Macromolecular Research
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• 제14권3호
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• pp.373-382
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• 2006

A series of crosslinkable, waterborne polyurethanes (I-WBPUs) were prepared by in-situ polymerization using isophorone diisocyanate (IPDI)/poly(tetramethylene oxide) glycol (PTMG, $M_n$=2,000)/dimethylol propionic acid (DMPA)/ethylene diamine (EDA)/triethylamine (TEA)/aminoplast[hexakis(methoxymethyl)melamine (HMMM)] as a crosslinking agent. Typical crosslinkable, waterborne polyurethanes (B-WBPUs) blended from WBPU dispersion and aqueous HMMM solution was also prepared to compare with the I-WBPUs. The crosslinking reaction between WBPU and HMMM was verified using FTIR and XPS analysis. The effect of the HMMM contents on the dynamic mechanical thermal, thermal, mechanical, and adhesion properties of the I-WBPU and B-WBPU films were investigated. The storage modulus(E'), glass transition temperatures of the soft segment ($T_{gs}$) and the amorphous regions of higher order ($T_{gh}$), melting temperature ($T_m$), integral procedural decomposition temperature (IPDT), residual weight, $T_{10%}$ and $T_{50%}$ (the temperature where 10 and 50% weight loss occurred), tensile strength, initial modulus, hardness, and adhesive strength of both I-WBPU and B-WBPU systems increased with increasing HMMM content. However, these properties of the I-WBPU system were higher than those of the B-WBPU system at the same HMMM content. These results confirmed the in-situ polymerization used in this study to be a more effective method to improve the properties of the WBPU materials compared to the simple blending process.

• Asian-Australasian Journal of Animal Sciences
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• 제16권10호
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• pp.1397-1401
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• 2003

The aim of this study was to determine genotypes of four genetic markers and to investigate their association with milk production traits in Brown Swiss cattle imported to Slovakia. The bovine $\kappa$-casein, $\beta$-lactoglobulin, growth hormone and prolactin genotypes of 107 cows were identified by polymerase chain reaction. Effects all four genetic markers on milk, fat, protein and lactose yields and fat, protein and lactose percentage were estimated from a data set of 249 lactations. The frequency of desirable B allele of $\kappa$-casein gene to milk production was 0.46, alleles A of $\beta$-lactoglobulin gene was 0.55, allele and L of growth hormone gene was 0.45 and allele A and B of bovine prolactin gene were 0.61 and 0.39. The results of milk production obtained in our work showed that BB genotypes of $\kappa$-CN gene, AA genotypes of $\beta$-LG gene, LL genotypes of bGH gene were significantly associated with better milk production traits, mainly about the fat content. Association of a bovine prolactin genotypes with milk production were not found.

• 한국환경보건학회지
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• 제46권4호
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• pp.368-375
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• 2020

Objectives: Some animal studies have reported that methyl mercury causes developmental toxicities such as placental and fetal weight loss, but the mechanism is still unclear. This study aimed to investigate the developmental toxicities of methyl mercury, focusing on placental endocrine function and fetal growth retardation in rats. Methods: Positively same-time-mated female Sprague-Dawley rats were purchased on gestational day (GD) eight and treated with 0, 5, 10 and 20 ppm of methyl mercury (n=5) dissolved in tap water from GD eight through 19. During treatment, the drinking water (methyl mercury) intake and body weight of each pregnant rat was measured daily. On day 19, caesarean sections were performed and blood samples were collected. Developmental data such as placental and fetal weights, fetus numbers, and placental efficiency (fetal weight/placental weight) were also collected. Placental prolactin-growth hormone (PRL-GH) family, such as placental lactogen (PL) -Iv, II, and prolactin-like protein (PLP) -B, levels in serum were analyzed by ELISA. Also, placental tissues were assigned to histochemistry. Results: The mean cumulative methyl mercury exposure for the 5, 10, and 20 ppm groups were 2.37, 4.63, and 9.66 mg, respectively. The mean daily exposure of the 5, 10, and 20 ppm groups were 0.24, 0.47, and 0.97 mg, respectively. Maternal body weight increased in accordance with GD. There was no significant difference in weight gain among the experimental groups. Histopathologic changes were not observed in placental tissues among the experimental groups. However, mean placental and fetal weights were lower in the 10 and 20 ppm exposed groups compared to the control. Placental efficiency was also lower in the 10 and 20 ppm exposed groups compared to the control. Serum PL-Iv and II levels were lower in the 10 and 20 ppm exposed groups than the control, in accordance with the changing pattern of placental and fetal weights and placental efficiency. Conclusion: The inhibitory effects of methyl mercury on the serum levels of placental PRL-GH family such as PL-Iv and II may be secondary leads to the reduction of placental efficiency and fetal growth retardation in rats.

• Asian-Australasian Journal of Animal Sciences
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• 제33권5호
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• pp.848-855
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• 2020

Objective: Shearing is one of the practices that is applied periodically to fiber producing animals, which can also alter resistance of animals to high temperatures in especially summer months. This study aimed to investigate effects of shearing on some physiological and hormonal parameters in Akkaraman sheep during summer season. Methods: This study was carried out on 39 non-pregnant Akkaraman ewes (aged 1.5 years at the beginning of experiment). The 39 ewes were chosen randomly from the flock belonging to the Erciyes University and they were assigned to two groups as follows: i) group A (n = 20) designed as the control group, they were shorn and group B (n = 19) designed as the experimental group, they were unshorn. Prior to the shearing (-1 day) and on days 1, 7, 15, 30, 45, 60, 75, and 90 following the shearing, blood samples were taken from the vena jugularis of each sheep. Cortisol, β-endorphin, growth hormone (GH), thyroxine (T₄), triiodothyronine (T₃), and heat shock protein 70 (HSP-70) concentrations were determined using the enzyme immunoassay method. Body weight (BW), rectal temperature (RT), pulse rate (PR), and respiratory rate (RR) of each sheep were recorded at the same time. The data obtained were analyzed using two-way repeated measures analysis of variance. Results: Statistical analysis showed a significant effect of shearing×period interaction (p<0.01) and a significant effect of period (p<0.01) on BW, HSP-70, cortisol, T₄ and RT, PR, GH, β-endorphin, T₃, respectively. Also these analysis showed no significant effect of shearing×period interaction or period on RR. Conclusion: The results showed that the thermoregulation abilities of sheep were affected by shearing treatment and the shorn ewes were less affected by heat stress. In conclusion, based on the data of this study, shearing can be considered as a necessary management practice that requires protection for sheep from the effect of heat stress.

• KSBB Journal
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• 제16권5호
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• pp.500-504
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• 2001

Sepharose CL-6B 의 기능기를 aldehyderl로 활성화시킨 후 urokinase와 공유결합 시켜 고정화하는 방법을 6mL 규모에서 250 mL 규모로 스케일업한 결과 고정화 수율 및 고정화 된 UK에 의한 절단반응 수율 등에서 스케일업 전후의 결과에 차이가 없었다. 따라서 위의 고정화 방법의 scale-up 효능은 매우 우수한 것으로 나타났다. hGH와 GST 절편으로 구성된 융합 단백질의 고정화 UK 컬럼에 의한 절단 반응 후 용출액의 pH를 3.5로 낮춤으로써 이물질들을 침전시키고 이를 expanded bed chromatography zf칼럼에 통과시킨 결과, 이 물질들의 제거와 hGH 단량체의 흡착분리가 동시에 이루어졌다. 흡착된 단량체는 NaCL에의해 용출되었으며 이 단계의 수율은 거의 100%이었다. 따라서 칼럼에 의한 절단 반응과 t산 침전에 의한 이물질 침전 바능, EBA에 의한 이물질 제거 및 단량체 회수 반응을 연속적으로 진행할 수 있는 기초를 제시하였다. 또한 고정화된 UK는 guanidine HCl(6 M)을 이용하여 unfolding 시키고 이를 세적하여 refolding 시킨 결과 20회의 반복적인 처리 후에도 초기 활성의 약 80% 수준을 유지하였다. 이는 UK 가 공유결합된 상태에서 solid-phase refolding이 가능하다는 증거이며, 고정화 효소 칼럼의 수명을 크게 향상시켜 경제성을 확보하는 방안으로 이용될 것으로 기대된다.

• KSBB Journal
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• 제15권1호
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• pp.42-48
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• 2000

본 연구에서는 고정화 UK를 이용한 융합단백질의 절단방응에 대해 UK의 고정화, 고정화 UK의 특성과 절단방응, 절단반응 후의 분리정제 그리고 고정화 UK으 재생에 대해 실험하였다. 고정화 수율은 99% 이상이였고 고정화 후의 효소활성은 80%를 유지하였다. 융합단백질 전단반응에서 액상 UK와 고정화 UK를 이용한 회분식 반응 모두 약 70%의 절단반응을 얻었고, 특히 고정화 UK의 사용시 부반응이 매우 낮은 이점이 있었다. 컬럼식 절단반응에서는 기절의 주입속도에 따라 절단수율은 크게 변화하였다. 최적의 유속은 50%의 절단수율을 얻은 1 bed volume/h로 설정하였다. 고정화 효소반응의 이점인 안정성과 반복사용 측면에서는 액상 UK 대비 고정화 UK가 높은 열안정성을 보였고 낮은 pH에서는 10% 이상 높은 활성을 유지하였다. 반복사용을 위해 6M GuHCl을 사용하여 인위적으로 풀림, 재접힘을 한 경우 98%의 활성을 얻음으로 타당성이 있음을 제시하였다. 또한 목적 단백질의 분리를 위하여 산침전 후 expanded bed adsorption 크로마토그래피를 이용함으로써 연속화된 고수율의 정제공정을 가능하게 하였다. 이러한 고정화 UK를 이용한 절단방응 및 정제시스템을 구축함으로써 융합단백지의 생산공정에 매우 유용하게 사용될 것으로 생각되어진다.

• BMB Reports
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• 제53권2호
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• pp.100-105
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• 2020

While liver histopathology is heterogeneous in diabetes, the underlying mechanisms remain unclear. We investigated whether glycemic variation resulting from differential diets can induce heterogeneity in diabetic liver and the underlying molecular mechanisms. We generated end-stage non-obese diabetic model rats by subtotal-pancreatectomy in male Sprague-Dawley rats and ad libitum diet for 7 weeks (n = 33). The rats were then divided into three groups, and fed a standard- or a low-protein diet (18 or 6 kcal%, respectively), for another 7 weeks: to maintain hyperglycemia, 11 rats were fed ad libitum (18AL group); to achieve euglycemia, 11 were calorie-restricted (18R group), and 11 were both calorie- and protein-restricted with the low-protein diet (6R group). Overnight-fasted liver samples were collected after the differential diets together with sham-control (18S group), and histology and molecular changes were compared. Hyperglycemic-18AL showed glycogenic hepatopathy (GH) without steatosis, with the highest GSK-3β inactivation because of Akt activation during hyperglycemia; mitochondrial function was not impaired, compared to the 18S group. Euglycemic-18R showed neither GH nor steatosis, with intermediate GSK-3β activation and mitochondrial dysfunction. However, euglycemic-6R showed both GH and steatosis despite the highest GSK-3β activity and no molecular evidence of increased lipogenesis or decreased ApoB expression, where mitochondrial dysfunction was highest among the groups. In conclusion, heterogeneous liver histopathology developed in end-stage non-obese diabetic rats as the glycemic levels varied with differential diets, in which protein content in the diets as well as glycemic levels differentially influenced GSK-3β activity and mitochondrial function in insulin-deficient state.

• 전기전자학회논문지
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• 제21권3호
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• pp.219-226
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• 2017

본 논문에서는 Mu-negative Metamaterial 단일 셀을 사용하여 700MHz대역과 2.45GHz 대역에서 동작하는 이중대역 모노폴 안테나 설계에 관하여 연구하였다. Mu-negative metamaterial 단일셀은 interdigital capacitor 구조를 사용하였고, 안테나 방사부에 삽입함으로써 이중대역 안테나를 구현하였다. 또한 기생도체를 안테나 방사부 뒷면에 있도록 구현하여 안테나의 공진점을 제어할 수 있고, 대역폭을 개선하였다. 최종적으로 750MHz UHD대역과 2.45GHz WiFi 대역에서 동작하는 안테나를 구현하였다. 설계제작한 안테나의 크기는 $200{\times}100mm^2$이고, 실험 결과 750MHz 대역에서 8dB 대역폭과 이득특성은 각각 320MHz(42.8%), 5.28dB, 2.45GHz에서 6dB 대역폭과 이득은 540MHz(21.6%), -0.46dB이다. 공진점은 이론값과 실험값이 일치하였으며, 방사패턴은 두 대역에서 전방향 특성을 갖고 있음을 확인하였다.

• 한국식품저장유통학회지
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• 제24권2호
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• pp.206-214
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• 2017

본 연구에서는 긴병꽃풀의 항산화 효과와 기능성을 활용한 양갱을 제조하여 기계적 특성을 측정하고, 관능적 기호도 평가를 실시하였다. 생리활성 물질의 양을 측정하기 위하여 페놀성 화합물 정량을 실시한 결과 긴병꽃풀 열수추출물에서 $12.99{\pm}0.30mg/g$, 70% ethanol 추출물에서 $3.14{\pm}0.07mg/g$으로 나타내었다. $50-200{\mu}g/mL$의 농도에서 항산화 효과를 측정한 결과, 전자공여능은 열수추출물과 70% ethanol 추출물에서 각각 77.16-78.24%, 73.04-77.00%로 나타내었으며, ABTS는 84.35-99.75%, 83.74-99.55%로 나타내었다. Antioxidant protection factor(PF)는 1.54-1.62, 1.62-2.09 PF를 나타내었으며, TBARs는 42.93-94.09%, 91.05-95.19%로 나타내었다. 긴병꽃풀 추출물의 열수추출물과 70% ethanol 추출물은 거의 비슷한 항산화 효과를 나타내었으나, PF와 TBARs에서는 70% ethanol 추출물에서 더 우수한 항산화 효과를 나타내었다. Tyrosinase 저해활성은 열수추출물에서는 효과가 나타나지 않았으며, 70% ethanol 추출물에서는 30.32-40.56%의 저해활성을 나타내었다. Hyaluronidase 저해활성은 14.23-40.93%, 57.45-72.88%로 70% ethanol 추출물이 더 우수한 저해활성을 나타내었으며, $50-100{\mu}g/mL$의 저농도에서는 positive control로 사용한 PDTC보다 우수한 저해활성을 나타내었다. 색도는 긴병꽃풀 분말의 첨가량이 증가할수록 L 값과 a 값은 감소하는 경향을 나타내었고 b 값은 일정하게 나타내었다. 기계적 조직감은 경도와 탄력성에서 긴병꽃풀 분말의 첨가량이 증가할수록 감소하는 경향을 나타내었고, 응집성은 첨가량과 관계없이 일정한 값을 나타내었다. 씹힘성은 2.0%에서 가장 높은 수치를 나타내었으나 대조군과 첨가군 간의 유의적 차이는 나타나지 않았고, 긴병꽃풀 분말이 양갱의 기계적 조직감에 영향을 준다는 것을 확인할 수 있었다. 긴병꽃풀 분말 첨가 양갱의 관능적 기호도는 점도, 경도, 씹힘성, 탄력성, 맛, 향, 전반적인 기호도 항목에서 대조군을 제외하고 1.0% 이하 첨가군에서 기호도가 높게 나타내었으며 2.0% 첨가군은 모든 항목에서 가장 낮은 기호도를 나타내었다. 위 결과에 따라 긴병꽃풀 분말을 이용한 양갱 제조에는 1.0% 이하의 농도를 사용하여 제조하는 것이 가장 적합하다고 판단되었다.

• 한국식품위생안전성학회:학술대회논문집
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• 한국식품위생안전성학회 1994년도 추계 학술 심포지움
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• pp.15-26
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• 1994

Bovine somatotropin(bST) or bovine growth hormone (bGH) is a protein of 191 amino acids produced by the anterior pituitary gland of cattle. Recombinant bovine somatotropin(rbST) is biosynthetic versions of the naturally occurring pituitary hormone in cows. The use of rbST in dairy cows promises to improve the efficiency of milk production around the world. Using recombinant DNA technology, bST can now be produced in commercial quantities. The recombinant bST(rbST) is biologically identical to the found in the bovine pituitary. Milk from rbST-treated cows has been found to have the same nutritional value and composition as milk from untreated cows. In November of 1993, rbST finally was approved by the FDA, nearly 10 years after filing a licence applica-tion. rbST has been one of the most extensively studied animal drug products to be reviewed by the agency. Three scientific facts will help to reassure the public about the safety of the milk suppy.: 1. rbST has no biological activity in humans when indigested orally or when given by intramuscular injection. 2. Insulin-like growth factor 1(IGF-1) is not orally active. Any changes in IGF-1 levels in milk are well within normal variation and are lower than those reported in human milk. 3. All cow's milk contains bST, and no significant change in bST levels in milk occurs as a result of giving cows supplemental bST. Based on the scientific evidence, the public can be confident that milk and meat from rbST-treated cows is safe to consumers.