• 한국연소학회지
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• 제22권4호
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• pp.1-8
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• 2017

This study was conducted to evaluate the fire retardant performance of exfoliated graphite nanoplatelets (xGnP) applied for particleboard. This work measured heat release rate(HRR), total heat release(THR) and smoke production rate(SPR) of xGnP added particleboard, using cone calorimeter to assess its fire characteristics according to the KS F ISO 5660-1 standard code. Heat release rates of all specimens treated by xGnP were less than the $200kW/m^2$ for a total experiment period of five minutes. Heat release rates of the specimens coated with xGnP were lower than those of the specimens made by mixing wood particles with xGnP directly. Meanwhile, the total heat release rates of xGnP coated specimen maintained quite lower level than the uncoated so the xGnP coating were effective in improving the fire retardant performance of particleboard. However, the smoke emission peaking problem at the initial combustion period, which was caused by adding base coating materials, should be resolved for further satisfaction as a fire retardant materials.

• Journal of Electrochemical Science and Technology
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• 제14권1호
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• pp.51-58
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• 2023

The effective detection of human chorionic gonadotropin (HCG) is considerably important for the clinical diagnosis of both of early pregnancy and nonpregnancy-related diseases. In this work, a simple and sensitive electrochemical sandwich-type immunosensing platform was designed by synthesizing b-cyclodextrin (CD) functionalized graphene (CD/GN) hybrid as simultaneously sensing platform and signal transducer coupled with rhodamine b (RhB) as probe. In brief, GN offers large surface area and high conductivity, while CD exhibits superior host-guest recognition capability, thus the primary antibody (Ab1) of HCG can be bound into the cavities of CD/GN to form stable Ab1/CD/GN inclusion complex; meanwhile, the secondary antibody (Ab2) and RhB can also enter into the cavities, producing RhB/Ab2/CD/GN complex. Then, by using Ab1/CD/GN as sensing platform and RhB/Ab2/CD/GN as signal transducer (in which RhB was signal probe), a simple sandwich-type immunosensor was constructed. Under the optimum parameters, the designed immunosensor exhibited a considerable low analytical detection of 1.0 pg mL^-1 and a wide linearity of 0.002 to 10.0 ng mL^-1 for HCG, revealing the developed sandwich-type electrochemical immunosensing platform offered potential real applications for the determination of HCG.

• 한국태양에너지학회 논문집
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• 제33권1호
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• pp.73-78
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• 2013

Hexadecane and exfoliated graphite nanoplate (xGnP)composite was prepared as a shape-stabilized phase change material (SSPCM) in a vacuum to develope thermal energy storage. The Hexadecane as an organic phase change material (PCM) is very stable against phase separation of PCM and has a melting point at $18^{\circ}C$ that is under the thermally comfortable temperature range in buildings. The xGnP is a porous carbon nanotube material with high thermal conductivity. Scanning electron microscope (SEM) and Fourier transformation infrared spectrophotometer (FT-IR)were used to confirm the chemical and physical stability of Hexadecane/xGnP SSPCM. In addition, thermal properties were determined by Deferential scanning calorimeter(DSC) and Thermogravimetric analysis (TGA). The specific heat of Hexadecane/xGnPSSPCM was $10.0J/g{\cdot}K$ at $21.8^{\circ}C$. The melting temperature range of melting and freezing were found to be $16-25^{\circ}C$ and $17-12^{\circ}C$. At this time, the laten heats of melting and freezing were 96.4J/g and 94.8J/g. The Hexadecane was impregnated into xGnP as much about 48.8% of Hexadecane/xGnP SSPCM's mass fraction.

• 대한수의학회지
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• 제21권1호
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• pp.59-64
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• 1981

Holstein-Friesian cows(n=284) were given $100{\mu}g$ of gonadotropin-releasing hormone(GnRH) or saline solution by intramuscular injection at 10 to 22 days after parturition, and were investigated their reproductive performance and frequency of ovarian cysts. Among them 28 cystic cows were injected with $150{\mu}g$ of GnRH intramuscularly and examined the recovery rate. The results obtained in this study were summarized as follows: 1. The interval from calving to 1st ovulation was reduced from 28.2 days in controls to 16.5 days for cows given GnRH (p<0.01). 2. The intervals from calving to 1st estrus and from calving to conception were extended significantly in control group (p<0.05). 3. Inseminations per conception and conception rate at 1st insemination did not reveal difference between two groups. 4. Frequency of ovarian cysts was reduced from 14.0% in control to 4.20% for cows given GnRH (p<0.05). 5. Of the 28 cystic cows receiving $150{\mu}g$ of GnRH, 23(82.1%) responded to 1st treatment and returned to estrus $24.2{\pm}4.3$ days after treatment. 6. These data provide evidence for reduction in infertility and reproductive disorders in early postpartum dairy cows given GnRH as a prophylactic.

• 대한수의학회지
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• 제63권2호
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• pp.14.1-14.4
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• 2023

This study evaluated the effect of resynchronization programs on pregnancies in dairy cows. Of 1,342 cows confirmed not pregnant after their first artificial insemination (AI), those with a corpus luteum (CL) were resynchronized using Ovsynch or PG-GnRH-Ovsynch and those without a CL were resynchronized using GnRH-Ovsynch or modified Double-Ovsynch. There were no differences (p > 0.05) in the pregnancies per AI either between the Ovsynch (31.3%) and PG-GnRH-Ovsynch (34.0%) or between the GnRH-Ovsynch (38.7%) and modified Double-Ovsynch (39.5%). In conclusion, Ovsynch and GnRH-Ovsynch programs could be preferred to resynchronize cows with and without a CL, respectively, from the perspective of reducing costs and labor.

• 한국발생생물학회지:발생과생식
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• 제7권1호
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• pp.35-40
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• 2003

성선자극호르몬 분비호르몬은 시상하부에서 분비되며, 포유동물의 생식에 중추적인 역할을 담당한다. 골든 햄스터는 계절적으로 번식하는 포유동물이며, 생식 활동은 광주기(하루 중 낮의 길이)에 의해 결정된다. 장주기(12.5 시간 이상의 빛)는 생식 능력을 유지시키지만, 단주기(12시간 이하의 빛)는 생식 기능을 억제한다. 성선자극호르몬 분비호르몬과 광주기의 상호 관계를 자세히 조사하기 위하여 랫트 성선자극호르몬 분비호르몬 cDNA를 포함하는 벡터를 여러 농도로 골든 햄스터의 수컷에 주입하고 단주기에 유지하여 생식 활동을 개별적으로 조사하였다. 벡터를 고농도로 처리한 그룹의 골든 햄스터는 기타 실험 그룹에 비해 정소 퇴화가 의미있게(P<0.05) 가속되었다. GnRH의 맥동적 분비가 생식 능력을 유지하는 관점에서 보면, GnRH-cDNA를 포함하는 벡터는 GnRH를 일정하게 고농도로 분비했다고 사료된다. 이 결과는 GnRH를 포함하는 벡터가 뇌하수체 전엽을 desensitization시켜 정소 퇴화를 가속시켰음을 암시한다.

• 대한약리학회지
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• 제30권1호
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• pp.19-28
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• 1994

흰쥐의 뇌하수체 전엽배양세포에 gonadotropin-releasing hormone (GnRH)을 처리하였을 때 시간이 경과함에 따라 GnRH농도에 비례하여 luteinizing hormone(LH)의 분비가 증가하였으며, 2시간까지 급격하게 증가하였다. 또한 GnRH를 처리하였을때 ${\alpha}$ subunit mRNA의 농도는 증가하지 않았으나 $LH{\beta}$ subunit mRNA의 농도는 GnRH 농도에 비례하여 증가하였으며, GnRH 처리후 6시간 이후부터 유의하게 증가하였다. 특히 최종농도가 $2{\times}10^{-10}M$이 되도록 GnRH를 처리하였을 때 $LH{\beta}$ subunit mRNA 농도가 2.7배 정도 최대로 증가하였다. 또한 estradiol을 단독으로 또는 GnRH와 동시에 처리하였을때 LH분비가 증가하지 않았으나 progesterone을 GnRH와 동시에 처리하였을때 LH분비가 유의하게 증가하였다. 또한 $LH{\beta}$ subunit mRNA의 농도는 estradiol및 progesterone을 단독으로 또는 GnRH와 동시에 처리하였을때 난소호르몬 농도에 의존적으로 $LH{\beta}$ subunit mRNA의 농도가 증가하였다. Estradiol에 의한 $LH{\beta}$ subunit mRNA의 증가양상은 estrogen 길항제인 LY117018에 의하여 유의하게 감소하였다. 이러한 결과로 보아 GnRH는 steady state $LH{\beta}$ subunit mRNA 농도에 영향을 미치므로써 LH분비 및 LH subunit 생합성을 조절하며 난소호르몬은 뇌하수체에 직접 작용하여 LH분비 및 LH subunit 생합성에 영향을 주는 것으로 보인다.

• 한국임상수의학회지
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• 제21권4호
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• pp.384-394
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• 2004

This study was carried out to monitor the response of ovaries and cyst according to treatment with GnRH or combination of GnRH and $PGF_2{\alpha}$ in dairy cows with ovarian follicular cysts. Thirty cows were diagnosed as having follicular cysts by rectal palpation, ultrasonography and progesterone (P4) assays. Ten cows were treated with GnRH (control), and the other twenty were treated with $PGF_2{\alpha}$ at 10 days after GnRH treatment. All the animals were re-examined by ultrasonography and blood was collected for the measurement of plasma P4 concentration at day 0 (the day of treatment), day 7, day 10, day 13, day 24 and day 34, respectively. In 30 cows that were diagnosed with follicular cysts, mean plasma P 4 concentrations on day -II and day -I were 0.3 ng/ml and 0.4 ng/ml. On day 10 increased as 2.7$\pm$0.2 ng/ml. Mean cystic wall thickness by ultrasonography on day -11 and day -I were 2.1 mm and 2.2 mm. In 9 cows responded on luteinization of cystic wall, cystic wall thickness was 3.9$\pm$0.5 mm at day 10 after GnRH treatment. The responses of ovaries until day 10 after GnRH treatment included development of corpus luteum in the ovary bearing the cyst or in the contralateral ovary (12 cows), luteinization of cystic wall (6 cows) and clouding of the anechoic antrum of cysts (2 cows). The ovarian responses according to the combination of GnRH and $PGF_2{\alpha}$ included regression of the corpus luteum (12 cows), increase (1 cow) and no change (1 cow) of cyst size until last examination, and complete disappearance on day 13 (6 cows), 23 (6 cows) and 34 (4 cows). Combination treatment group of GnRH and $PGF_2{\alpha}$ showed a higher pregnancy rate within 100 days after initial treatment (40.0 vs 65.0%) and shorter intervals from the treatment to conception (45.4$\pm$25.8 vs 53.5$\pm$31.4 days) compared with control. It was concluded that the administration of $PGF_2{\alpha}$ following GnRH treatment is effective in shortening the interval from treatment to conception in cows with follicular cyst. Also, this study suggested that the response of the cyst according to treatment revealed various types. Therefore, veterinarians should pay attention to monitor of the response of cystic ovaries after treatment, specially no change, slowly decrease or increasement of cyst size after treatment.

• 한국발생생물학회지:발생과생식
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• 제1권2호
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• pp.189-202
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• 1997

The hypothalamic peptide GnRH plays a central role in the regulation of the mammalian reproductive axis. Recent studies suggested that GnRH stimulates or inhibits the ovarian steroidogenesis and gametogenesis directly. Our previous report indicated that GnRH gene is expressed in adult rat ovary as well as in hypothalamus and that the expressed GnRH may induce the follicular atresia and apoptosis of ovarian granulosa cells in rat. Therfore, we studied whether GnRH gene is expressed in the mouse fetal ovary, when the germ cells are degenerating by apoptosis during gonad diffeerentiation. Mouse fetal gonads were obtained on the 12, 15,18 and 20th day of gestation from the mother mice superovulated (10 IU PMSG and 10 IU hCG) and mated. The morphological changes of fetal ovaries were examined histochemically by hematoxylin-eosin staining. The fetal sex was confirmed by PCR methods for sexing. RT-PCR methods were used to examine the expression of GnRH gene and the sex steroid hormones were determined by conventional radioimmunoassays. The levels of estradiol (E) and progesterone (P) were increaseduntil 18th day of gestation and then E was decreased just before parturition. The morphological changes of fetal gonadal tissue sections showed the ovarian development and coincided with the result of PCR analysis for sexing using ovary- or testis- specific oligonucleotide primers. Immunoreactive GnRH in placenta was decreased gradually until the end of gestation but fetal brain and ovarian GnRH were increased. The level of GnRH gene expression was increased during fetal ovarian development from 12 till 18th day and decreased suddenly on 20th day just before birth. From these results, it is suggested that ovarian GnRh may play a regulatory role on the germ cell differentiation of fetal ovary.

• 한국수정란이식학회지
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• 제23권2호
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• pp.109-114
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• 2008

This study examined pregnancy and fetal loss rates according to different estrus synchronization protocols and injection of gonadotropin releasing hormone (GnRH) after transfer of Korean Native Cattle embryos to Holstein recipients. In Experiment 1, recipients received no treatment (Control, n = 119); two injections of prostaglandin$F_{2{\alpha}}$ ($PGF_{2{\alpha}}$ ) 11 days apart (PGF group, n = 120); GnRH (day 0)-$PGF_{2{\alpha}}$ (day 7)-GnRH (day 9) (Ovsynch group, n = 120); and CIDR (day 0)-$PGF_{2{\alpha}}$ and CIDR removal (day 7)-GnRH (day 9) (CIDR group, n = 110). In Experiment 2, the control group was received no treatment of GnRH. The treatment groups were received GnRH at embryo transfer (ET) (day 0), 7 days later, 14 days later, ET and 7 days later, 7 and 14 days later, or ET, 7 and 14 days later. Recipients were assigned to treatment randomly and received two in vitro produced blastocysts. Pregnancy was diagnosed at day 60 by palpation per rectum. Fetal loss to term was determined by palpation every 90 days thereafter. In Experiment 1, the pregnancy rate in the CIDR group (59.1%) were higher than in the Control group (42.0%) (p<0.01); fetal loss rates were similar for all groups (12.0 to 18.5%). In Experiment 2, the pregnancy rate in Day 0+7+14 group was higher (60.2%) than the control (40.2%) (p<0.01) and resulted in a lower fetal loss (p<0.05) than the control (4.6 vs. 11.4%). There were no significant difference between other treatment and the control (p>0.05). These results show that pregnancy rates of bovine embryos can be enhanced by CIDR insertion or GnRH $3{\times}$ treatment. Additionally, fetal loss may be reduced with GnRH treatment after ET.