• 한국측량학회지
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• 제38권6호
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• pp.717-723
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• 2020

VLBI, SLR, DORIS, GNSS와 같은 우주측지기술 사이의 3차원 벡터를 결정하는 작업은 ITRF에 중요한 요소이다. 따라서 각각의 우주측지기술에 해당되는 IVP를 정확하게 계산할 필요가 있다. 본 연구에서는 기존 모델에 비해 업데이트된 수학모델을 사용하여 세종시에 위치한 VLBI의 IVP 위치를 계산함으로써 계산의 효율과 신뢰성을 높였다. 관측값으로는 안테나에 부착된 반사타겟의 좌표가 사용되었으며 이때 관측오차크기는 1.5 mm로 설정하였다. 조정계산을 통해 VLBI IVP 좌표와 정확도를 계산했으며 기존 연구에서 제시한 값과 비교했을 때 성공적으로 계산이 된 것으로 판단된다. 하지만 실제 관측오차가 고려된 VLBI IVP를 계산하기 위해서는 향후 VLBI IVP 계산을 위한 추가적인 지상측량이 필요하다.

• 한국수정란이식학회지
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• 제15권3호
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• pp.255-261
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• 2000

The objective of this study was to improve the efficiency of bovine embryo transfer by transferring of Hanwoo embryos into Hanwoo or Holstein recipients. The cryopreserved or fresh in vitro produced(IVP) embryos were transferred into uterine horn contralaterally or ipsilaterally to the corpus luteum. The recipients were inseminated by artificially on the next day of estrus. The pregnancy was diagnosed by rectal palpation at 60∼90 days after transfer of the embryos. The pregnancy rate by transfer of one or two embryos was 78%(7/9) and 74%(31/42), respectively. The pregnancy rates according to the grade of corpus lutea of recipients was 75% (20/27) and 82.0%(18/22) at the grade of A and B, respectively. Ten(67.0%) of 15 Holstein recipients transferred with IVP Hanwoo embryos and 5(42.0%) of 12 Holstein recipients transferred with frozen IVP Hanwoo embryos were pregnant. The single and twin calving ratio in Hanwoos was 77.0%(10/13) and 23.0%(3.13) in the recipients transferred with IVP embryos and 64.0%(7/10) and 27.0%(3/10) in the recipients transferred with frozen IVP embryos, respectively. Twenty-four pregnant cows following transfer of IVP embryos, 21(88.0%) calved the normal calves, and 2(8.3%) aborted. When the frozen IVP embryos were transferred, 16 pregnant cows calved 14(88.0%) normal calves and 2(13.0%) aborted. In conclusion, when one or two IVP bovine embryos were transferred into recipients, the A and B grade of corpus luteum resulted in high pregnancy rates. For the production of twin calves, transfer of the IVP or frozen IVP embryos could be suitable.

• Educational Technology International
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• 제23권2호
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• pp.129-155
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• 2022

This study sought to design and develop an interactive video player (IVP) capable of promoting student engagement through the use of online video content. We designed features built upon interactive, constructive, active, passive (ICAP), and crowd learning frameworks. In the development stage of this study, we integrated numerous interactive features into the IVP intended to help learners shift from passive to interactive learning activities. We then explored the effectiveness and usability of the developed IVP by conducting an experiment in which we evaluated students' exam scores after using either our IVP or a conventional video player. There were 158 college students who participated in the study; 76 students in the treatment group used the IVP and 82 students in the control group used a conventional video player. Results indicate that the participants in the experiment group demonstrated better achievement than the participants in the control group. We further discuss the implications of this study based on an additional survey that was administered to disclose how usable the participants perceived the IVP to be.

• 한국동물생명공학회지
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• 제38권2호
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• pp.47-53
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• 2023

Despite numerous advances in in-vitro embryo production (IVP), many documented factors have been shown to influence the development of mammalian preimplantation embryos and the success of IVP. In this sense, elevated levels of reactive oxygen species (ROS) correlate with poor outcomes in assisted reproductive technologies (ART) due to oxidative stress (OS), which results from an imbalance between ROS production and neutralization. Indeed, excessive production of ROS compromises the structural and functional integrity of gametes and embryos both in vivo and in vitro. In particular, OS damages proteins, lipids, and DNA and accelerates cell apoptosis. Several in-vivo and in-vitro studies report an improvement in qualityrelevant parameters after the use of various antioxidants. In this review, we focus on OS and the source of free radicals and their effects on oocytes, sperm, and the embryo during IVP. In addition, antioxidants and their important role in IVP, supplementation during oocyte in vitro maturation (IVM), in vitro culture (IVC), and semen extenders were discussed. Nevertheless, various methods for determining the level of ROS in germ cells have been briefly described. Still, it is crucial to develop standardized antioxidant supplement systems to improve overall IVP success. Further studies should explore the safety, efficacy, mechanism of action, and combination of different antioxidants to improve IVP outcomes.

• 대한의용생체공학회:의공학회지
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• 제18권1호
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• pp.25-36
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• 1997

To regulate cardiac output of the Total Artificial Heart(TAH) physiologically, the hemodynamic information must be toed back to the controller. So far, our group has developed an automatic cardiac output control algorithm using the motor current waveform, It is, however difficult to detect the preload level such as a filling status of ventricular inflow and the variation of atrial pressures within normal physiologic range(0-15 mmHg) by analyzing the motor current which simultaneously reflects the afterload effect. On the other hin4 the interventricular volume pressure(IVP) which is not influenced by arterload but by preload is a good information source for the estimation of preload states. In order to find the relationship between preload and IVP waveform, we set up the artificial heart system on the Donovan type mock circulatory system and measured the IVP waveform, right and left atrial pressures, inflow and outflow waveforms and the signals represented the information of moving actuator's position. We shows the feasibility of estimating the hemodynamic changes of inflow by using IVP waveform. fife found that the negative peak value of IVP waveform is linearly related to atrial pressures. And we also found that we could use the time to reach the negative peak in IVP waveform, the time to open outflow valve, the area enclosed IVP waveform as unfu parameters to estimate blood filling volume of diastole ventricle. The suggested method has advantages of avoiding thrombogenesis, bacterial niche formation and increasing longterm reliability of sensor by avoiding direct contact to blood.

• 한국수정란이식학회지
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• 제16권1호
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• pp.29-34
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• 2001

To investigate the effect of co-transfer of trophoblastic vesicle (TV) with frozen-thawed in vitro Produced (IVP) bovine embryo on pregnancy rate, IVP blastocysts were transferred to synchronized recipients. Elongated blastocysts were recovered at Day 13 to 15, and dissected more than 4 pieces to removed the embryonic disc. Throphoblastic fragments were cultured for 48 hours to make throphoblastic vesicles (TVs). TVs were cryopreserved in ethylene glycol or vitrification solution and frozen-thawed TVs were co-transferred to recipients with frozen-thawed IVP embryos. 1 The recovery rate of elongated blastocyst on Day 13 to 15 was 22.5% (18/80) and the size of recovered elongated blastocysts was 0.2∼5.0mm. 2. Eighteen elongated blastocysts were dissected into 88 pieces and 61.4% of those pieces were formed to TV (54/88) 3. The viability of frozen-thawed TV in ethylene glycol was higher than in vitrified solution (92.8% vs. 68.8%) 4. The pregnancy rate in co-transfer with frozen-thawed TV and IVP blastocyst was better than transfer only IVP blastocysts (50.0% vs. 23.1%).

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2002년도 국제심포지엄
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• pp.8-17
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• 2002

There have been intensive attempts to establish reliable methods far in vitro production (IVP) methods for of porcine embryos. Although a great deal of progress has been made, our current IVP systems still need to be improved. In this review, we focused on studies about in vitro maturation and fertilization (IVM-IVF) of porcine oocytes and their in vitro culture (IVC), especially on an excellent piglets production system using modified IVP system producing porcine blastocysts with high Quality.

• 한국수정란이식학회지
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• 제30권3호
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• pp.149-159
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• 2015

This study was designed to know the possibility in repeat uses of elite donor cows for getting mass production of OPU-derived embryo production (OPU-IVP). Ultrasound transvaginal ovum pick-up (OPU) performed in 6 Korean native cows was aged 4 to 10 years old. The aspiration of immature oocytes for OPU derived embryo was carried out 2 times per week, and OPU-IVP of $1^{st}$ period was carried out 22~48 sessions from each donors. And the break time for OPU-IVP of $2^{nd}$ period after $1^{st}$ OPU from each donors were 2~25 months. The OPU-IVP of $2^{nd}$ period each donors conducted total 15~65 times for 2~8 months by an ultrasonographic, was guided follicular aspiration system. The average numbers of collected oocytes, grade 1 + grade 2(G1+G2) oocytes and cleavage embryo from $1^{st}$ period OPU-IVP were significantly differences between donors (p<0.05). Total collected oocytes of donor D were significantly higher compared with donors of A, B, C, E and F (average 17.0 per session vs. 11.2, 10.1, 8.5, 10.2 and 9.6; p<0.05) and also oocytes of G1+G2 were significantly higher compared with r A and D and subsequently to donors of B, C, E and F (average 7.9 and 8.5 per session vs. 5.0, 2.7, 6.0 and 1.6; p<0.05). Cleavage rate of donor D was significantly higher compared with donors of A, B, C, E and F (average 13.1 per session vs. 10.1, 9.1, 6.9, 8.9 and 6.7; p<0.05). The average numbers of OPU-IVP for $1^{st}$ period was significantly higher from donors of B, D and E than those from donors of A, C and F (average 6.5, 7.1 and 6.5 per session vs. 3.5, 4.2 and 2.8; p<0.05). The possibility investigation of $2^{nd}$ OPU-IVP was carried out after 2~25 months rest periods from $1^{st}$ period OPU session. Total average numbers of collected oocytes, cleavages and blastocyst development rates were significantly higher from $1^{st}$ period OPU compared with $2^{nd}$ period one (p<0.05). The OPU-IVP efficiency by break for more embryo production from elite cow was analysis comparing without rest of donor A, under 6 months rest period as B and over 6 months rest period as C and then the average numbers of collected oocytes, cleavages and blastocysts were significantly higher from A group (11.8, 9.5 and 5.2 per session) than those from B and C groups (7.9, 6.2 and 2.6 vs. 9.2, 7.5 and 3.9, p<0.05), and also C group was significantly higher than B group. In conclusion, $1^{st}$ period OPU-IVP was more efficient compared with $2^{nd}$ period repeated uses of donor, and the break times for additional production of embryo on donor were needed more than over 6 months after $1^{st}$ period OPU-IVP. This repeating uses of elite donor cows given more emphasis for getting the opportunity on mass production of elite cow OPU-IVP embryo should be increased G1+G2 possibility of genetic improvement of livestock within short period.

• Reproductive and Developmental Biology
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• 제39권2호
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• pp.29-36
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• 2015

Pigs are considered an ideal source of human disease model due to their physiological similarities to humans. However, the low efficiency of in vitro embryo production (IVP) is still a major barrier in the production of pig offspring with gene manipulation. Despite ongoing advances in the associated technologies, the developmental capacity of IVP pig embryos is still lower than that of their in vivo counterparts, as well as IVP embryos of other species (e.g., cattle and mice). The efficiency of IVP can be influenced by many factors that affect various critical steps in the process. The previous relevant reviews have focused on the in vitro maturation system, in vitro culture conditions, in vitro fertilization medium, issues with polyspermy, the utilized technologies, etc. In this review, we concentrate on factors that have not been fully detailed in prior reviews, such as the oocyte morphology, oocyte recovery methods, denuding procedures, first polar body morphology and embryo quality.

• 천문학회지
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• 제51권5호
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• pp.143-153
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• 2018

We present the first results of the invariant point (IVP) coordinates of the KVN Ulsan and Tamna radio telescopes. To determine the IVP coordinates in the geocentric frame (ITRF2014), a coordinate transformation method from the local frame, in which it is possible to survey using the optical instrument, to the geocentric frame was adopted. The least-square circles are fitted in three dimensions using the Gauss-Newton method to determine the azimuth and elevation axes in the local frame. The IVP in the local frame is defined as the mean value of the intersection points of the azimuth axis and the orthogonal vector between the azimuth and elevation axes. The geocentric coordinates of the IVP are determined by obtaining the seven transformation parameters between the local frame and the east-north-up (ENU) geodetic frame. The axis-offset between the azimuth and elevation axes is also estimated. To validate the results, the variation of coordinates of the GNSS station installed at KVN Ulsan was compared to the movement of the IVP coordinates over 9 months, showing good agreement in both magnitude and direction. This result will provide an important basis for geodetic and astrometric applications.