• Clinical and Experimental Reproductive Medicine
• /
• 제27권3호
• /
• pp.275-282
• /
• 2000

Objective: This study was to determine the effect of different concentration of calcium III medium on the preimplantational development of zygotes and early 2 cell embryos. Methods: Female mice of ICR strain ($5{\sim}8$ weeks old) were superovulated and mated with fertile males. Zygotes or early 2-cell embryos were collected by flushing the oviducts $31{\sim}32$ hours after hCG injection. The embryos were cultured in various concentrations of $Ca^{2+}$ in medium or with EDTA, EGTA and $Ni^{2+}$. Result and Conclusion: Treatment of high concentraion of $Ca^{2+}$ (3.42 mM $(2X){\sim}17.l$ mM (10X)) in medium didn't develop well compared to the control. Low concentrations of $Ca^{2+}$ (0.214mM $(1/8X){\sim}0.855$ mM (1/2X) were deterimental to development beyond 2-cell stage. EDTA, $Ca^{2+}$ chelating agent was treated with ranged concentrations of EDTA (0.014 $mM{\sim}0.107$ mM) to medium contaning 1.71 mM $Ca^{2+}$ showed beneficial effect to development to blastocyst compared to the control. EGTA, extracellular $Ca^{2+}$ chelator, was treated with ranged concentrations of EGTA ($0.014{\sim}0.107$ mM) to the medium contaning 1.71 mM $Ca^{2+}$. There is no significant difference with the control. $Ni^{2+}$ (50 ${\mu}M$), T-type $Ca^{2+}$-channel blocker was treated to medium contaning low concentration of $Ca^{2+}$. It overcame 2-cell block significantly. Rate of degenerated embryos decreased and developmental rate to morula and blastocyst increased more than low $Ca^{2+}$ concentration alone. Further studies are needed for the overcoming effect of 2-cell block by $Ni^{2+}$.

• 에너지공학
• /
• 제2권1호
• /
• pp.75-82
• /
• 1993

상용 모사기인 ASPEN PLUS를 이용하여 천연가스를 사용하는 50 ㎾ 인산형 연료전지시스템의 정상상태 전산모사를 실시하였다. 연료전지 본체의 모사를 위하여 USER 블럭과 FORTRAN 블럭을 작성하였다. 여러가지 조업조건에 따른 수소의 수율 변화를 살펴봄으로써 개질기의 효율을 최대로 하는 조업범위를 찾았고, 실제 경우와 근사한 결과를 얻었다. 이로부터 향후 실용화될 국내의 연료전지시스템에 대한 기본 자료와 최적조건을 제시할 수 있다. 기존의 발전효율을 얻기 위하여는 수소이용률이 50%, 이상으로 유지되어야 하며, 고온으로 조작되는 개질기와 연료전지 본체에서 발생되는 고온의 열을 효율적으로 회수하여 이용함으로써 공정의 에너지효율을 높일 수 있다.

• International Journal of Internet, Broadcasting and Communication
• /
• 제5권2호
• /
• pp.11-14
• /
• 2013

This paper describes the sigma-delta ADC/DAC digital block with two channels. The ADC block has comb filter and three half band filters. And the DAC block has 5th Cascaded-of-Integrators Feedback DSM. The ADC and DAC support I2S, RJ, LJ and selectable input data modes of 24bit, 20bit, and 16bit. It is fabricated with 0.35um Hynix standard CMOS cell library. The chip size is 3700*3700um. It has been verified using NC Verilog Simulator and Matlab Tool.

• Bulletin of the Korean Chemical Society
• /
• 제31권8호
• /
• pp.2265-2271
• /
• 2010

In this study, wormorm-like polymeric micelles were construted from poly(L-lactic acid)-b-poly(ethyelen glycol) (PLLA-b-PEG) block copolymers via worm-like (or cylindrical) self- assembly that consisted of a relatively long PLLA block ($M_n$ 7K Daltons) at the core and a relatively short PEG block ($M_n$ 2K Daltons) as the shell. Several cancer-targeting moieties (such as folate, cobalamin, and cyclic arginine-glycine-aspartic (RGD) peptide) were chemically coupled with the succinylated or maleimided PEG block of PLLA-b-PEG to act as a cancer cell-specific targeting ligand for breast cancer. The worm-like micelles with muplite cancer cell-specific ligands proved to be successful in recognizing different breast cancer cells at once. This has the potential to aid in cancer-specific drug delivery and to be used as an effective treatment for breast cancer.

• The Korean Journal of Physiology and Pharmacology
• /
• 제3권3호
• /
• pp.305-313
• /
• 1999

To explore whether $Cl^-$ channel blockers interact with the ATP-sensitive $K^+\;(K_{ATP})$ channel, I have examined the effect of two common $Cl^-$ channel blockers on the $K_{ATP}$ channel activity in isolated rat ventricular myocytes using patch clamp techniques. In inside-out patches, 4,4'-diisothio-cyanatostilbene- 2,2'-disulfonic acid (DIDS) and niflumic acid applied to bath solution inhibited the $K_{ATP}$ channel activity in a concentration-dependent manner with $IC_{50}$ of 0.24 and 927 ${\mu}M,$ respectively. The inhibitory action of DIDS was irreversible whereas that of niflumic acid was reversible. Furthermore, DIDS-induced block was not recovered despite exposure to ATP (1 mM). In cell-attached and inside-out patches, DIDS blocked the pinacidil- or 2,4-dinitrophenol (DNP)-induced $K_{ATP}$ channel openings. In contrast, niflumic acid did not block the pinacidil-induced $K_{ATP}$ channel openings in inside-out patches, but inhibited it in cell-attached patches. DIDS and niflumic acid produced additional block in the presence of ATP and did not affect current-voltage relationship and channel kinetics. All these results indicate that DIDS among $Cl^-$ channel blockers specifically blocks the cardiac $K_{ATP}$ channel.

• The Korean Journal of Pain
• /
• 제8권2호
• /
• pp.331-335
• /
• 1995

Asthma is a disease of the airways that is characterized by increased responsiveness of the tracheobronchial tree to a multiplicity of stimuli. A number of causes have been postulated for the increased airway reactivity of asthma is conservative as beta-adrenergic agonist, methylxanthines, glucocorticoids, anticholinergics and mast cell stabilizing agent. Stellate ganglion block for the treatment of bronchial asthma has its controversies. Stellate ganglion block was performed for the treatment of 3 patients with bronchial asthma. After stellate ganglion blocks, dyspnea, coughing and wheezing was markedly reduced. Lung function test improved with 1 st case. Two asthma cases were able to discontinue medication for asthma. No severe aggrevation of bronchial symptoms were noted after stellate ganglion blocks. It suggested that stellate ganglion block can be safely performed on bronchial asthmatic patients.

• 정보보호학회논문지
• /
• 제12권2호
• /
• pp.53-64
• /
• 2002

This paper describes a design of cryptographic processor that implements the AES (Advanced Encryption Standard) block cipher algorithm, "Rijndael". An iterative looping architecture using a single round block is adopted to minimize the hardware required. To achieve high throughput rate, a sub-pipeline stage is added by dividing the round function into two blocks, resulting that the second half of current round function and the first half of next round function are being simultaneously operated. The round block is implemented using 32-bit data path, so each sub-pipeline stage is executed for four clock cycles. The S-box, which is the dominant element of the round block in terms of required hardware resources, is designed using arithmetic circuit computing multiplicative inverse in GF($2^8$) rather than look-up table method, so that encryption and decryption can share the S-boxes. The round keys are generated by on-the-fly key scheduler. The crypto-processor designed in Verilog-HDL and synthesized using 0.25-$\mu\textrm{m}$ CMOS cell library consists of about 23,000 gates. Simulation results show that the critical path delay is about 8-ns and it can operate up to 120-MHz clock Sequency at 2.5-V supply. The designed core was verified using Xilinx FPGA board and test system.

• 농업과학연구
• /
• 제38권2호
• /
• pp.315-324
• /
• 2011

Riparian vegetation distribution patterns and diversity relative to various fluvial geomorphic channel patterns, stream bank stabilization methods, and stream flow processes are described and interpreted for selected nature-friendly small stream bank protection of Goesan, central Korea. Idong Stream Pilot Project, which began in May 2003 and finished in December 2003, was selected to develop effective methods which was nature-friendly stream bank protection. The project aim to maintain or increase stream bank stabilization ecosystem goods and services while protecting downstream and stream bank ecosystem. A number of protecting methods which were a Flight of fieldstone, Vegetation block, Green river block, Stone net, Green environment block, Eco friendly cobble, Vegetation mat and Geo-green cell and Firefly block were applied on the bank of Idong stream. The stream sites have been monitored about vegetation conditions each method in 2007. We selected six points to separately investigate in left and right bank. The main purpose of this study was to find out suitable methods and to improve stream restoration techniques for ecosystem. On the stream bank, H environment block method (9.7) was the highest average of vegetation coverage and Firefly block method (3.87) was the lowest average in applied methods.

• 한국발생생물학회:학술대회논문집
• /
• 한국발생생물학회 2003년도 제3회 국제심포지움 및 학술대회
• /
• pp.109-109
• /
• 2003

Even though success in birth of live offspring from nuclear transfer(NT) using somatic cells in many species, detailed information on processes or mechanisms of development are not well known. Cytoplasm of bovine oocyte has been known to support the development of nuclear transferred embryos using nuclear donor cells from different species. Therefore, interspecies NT might be used to find answers of some questions in basic aspect of nuclear transfer In this study, we examined the developmental potential of reconstructed embryos when bovine oocyte as a cytoplasm recipient and mouse embryonic fibroblast as a nuclear donor were used. The nuclear transfer units were aliocated in Group 1 (murine block media and normal media) and Group 2. (bovine block media and normal media). NT units were not blocked at 2-cell stage regardless of types of medium. On mouse media, poor development of interspecies NT units was observed compared to bovine media. However, as NT units cultured in bovine normal medium, embryos developed over 8-cell stage. Further studies performed to increase the developmental rate in condition of antioxidant treatment. Despite low development, bovine-murine interspecies nuclear transferred embryos could develop to blastocysts and they showed that blastocyts rate of antioxidant group was superior to those of non-antioxidant group. Next, we investigated gene expression pattern which is carried out for zygotic activation. The Xist gene is expressed in female mouse embryo after zygotic activation of 4-cell stage. But interspecies nuclear transferred embryos do not express Xist gene at 4-cell stage. As a result, it is suggested that the bovine cytoplasm controls the early preimplantation development in interspecies NT However, the development of later stages might require genomic control from transferred donor nucleus. Therefore, even though the involvement of several other factors such as mitochondrial incompatibility, effective development of embryos produced by interspecies NT requires proper genomic activation of donor nucleus after overcoming the cytoplasmic control of recipient oocytes.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제9권6호
• /
• pp.598-612
• /
• 2017

The recently developed Harmonic Polynomial Cell (HPC) method has been proved to be a promising choice for solving potential-flow Boundary Value Problem (BVP). In this paper, a flux method is proposed to consistently deal with the Neumann boundary condition of the original HPC method and enhance the accuracy. Moreover, fixed mesh algorithm with free surface immersed is developed to improve the computational efficiency. Finally, a two dimensional (2D) multi-block strategy coupling boundary-fitted mesh and fixed mesh is proposed. It limits the computational costs and preserves the accuracy. A fully nonlinear 2D numerical wave tank is developed using the improved HPC method as a verification.