Jong-im Park

A Continuous Strategy Game for Power Transactions Analysis in Competitive Electricity Markets

This article presents a game theory application for analyzing power transactions in a deregulated energy marketplace such as PoolCo, where participants, especially generating entities, maximize their net profits through optimal bidding strategies (i.e., bidding prices and bidding generations). In this article, the electricity market for power transactions is modeled as a noncooperative game with complete information, where the solution is determined in a continuous strategy domain having recourse to the Nash equilibrium idea. In order to provide more apprehensible analysis, we suggest a new hybrid solution approach employing a two-dimensional graphical approach as well as an analytical method. Finally, the proposed approach is demonstrated on a sample power system.

Radiographic and computed tomographic evaluation of experimentally induced lung aspiration sites in dogs.

This study was performed to radiographically examine the prevalence of aspiration sites and to evaluate their atomical correlation with the bronchial pattens. Ten healthy beagle dogs were repeatedly radiographed, at weekly intervals, in the left and right lateral, ventrodorsal (VD) and dorsoventral (DV) positions. Three mililiters of iohexol distilled with same volume of saline was infused into the tracheal inlet. Which lung lobe was aspirated was decided upon by the presence of a significant alveolar pattern due to the contrast medium. Alveolar patterns were identified at the left (100%) and right cranial lung lobes (77%) with the dogs in dependant lateral recumbency, at the right caudal lung lobe (71%) with the dogs in VD recumbency and at the right middle lung lobe (59%) with the dogs in DV recumbency, respectively. The anatomical correlation was evaluated by performing computed tomography. The right principal bronchus (165.8 ± 1.6°) was more straightly bifurcated than was the left principal bronchus (142.7 ± 1.8°, p < 0.01). In VD position, the right side lung had a greater opertunity to become aspirated. The ventrally positioned right middle lobar bronchial origin was more easily to be aspirated the other laterally positioned ones. We think that these anatomical characteristics can be one of the causes for aspiration pneumonia to occur more frequently in the right side lung.

Rapamycin treatment during in vitro maturation of oocytes improves embryonic development after parthenogenesis and somatic cell nuclear transfer in pigs

This study was conducted to investigate the effects of rapamycin treatment during in vitro maturation (IVM) on oocyte maturation and embryonic development after parthenogenetic activation (PA) and somatic cell nuclear transfer (SCNT) in pigs. Morphologically good (MGCOCs) and poor oocytes (MPCOCs) were untreated or treated with 1 nM rapamycin during 0-22 h, 22-42 h, or 0-42 h of IVM. Rapamycin had no significant effects on nuclear maturation and blastocyst formation after PA of MGCOCs. Blastocyst formation after PA was significantly increased by rapamycin treatment during 22-42 h and 0-42 h (46.6% and 46.5%, respectively) relative to the control (33.3%) and 0-22 h groups (38.6%) in MPCOCs. In SCNT, blastocyst formation tended to increase in MPCOCs treated with rapamycin during 0-42 h of IVM relative to untreated oocytes (20.3% vs. 14.3%, 0.05 < p < 0.1), while no improvement was observed in MGCOCs. Gene expression analysis revealed that transcript abundance of Beclin 1 and microtubule-associated protein 1 light chain 3 mRNAs was significantly increased in MPCOCs by rapamycin relative to the control. Our results demonstrated that autophagy induction by rapamycin during IVM improved developmental competence of oocytes derived from MPCOCs.

Colcemid treatment during oocyte maturation improves preimplantation development of cloned pig embryos by influencing meiotic progression and cytoplasmic maturation

The objective of this study was to examine the effects of colcemid treatment during oocyte in vitro maturation (IVM) and embryonic development after parthenogenetic activation (PA) and somatic‐cell nucleus transfer (SCNT) in pigs. Immature oocytes were treated with colcemid from 0 to 22, 38 to 42, or 0 to 22 hr followed by 38 to 42 hr during IVM (designated as COL0‐22, COL38‐42, and COL0‐22/38‐42, respectively). The proportion of oocytes reaching the germinal vesicle (GV)/GV breakdown (GVBD) stage after 22 hr of IVM was higher in COL0‐22 (98.4%) than in controls not exposed to colcemid (68.7%). The proportion of metaphase‐II (MII) oocytes after 30 hr of IVM was higher in control (79.6%) than in COL0‐22 oocytes (61.7%); overall nuclear progression to the MII stage was not influenced by colcemid treatment by the end of the IVM period (93.8, 86.7, 86.8, and 84.8% for control, COL0‐22, COL38‐42, and COL0‐22/38‐42, respectively). COL0‐22 oocytes showed higher intra‐oocyte glutathione content (1.7 vs. 1.0–1.3 pixels/oocyte) and increased blastocyst formation after PA (68.7% vs. 42.5–52.2%) and SCNT (39.4% vs. 16.3–28.6%) than control, COL38‐42, and COL0‐22/38‐42 oocytes. Colcemid treatment for 0–22 and 0–22/38‐42 hr of IVM also stimulated the expression of cyclin‐dependent kinase 1 (CDK1), proliferating cell nuclear antigen (PCNA), and extracellular signal‐regulated kinase 2 (ERK2) mRNAs. Our results thus demonstrate that the presence of colcemid during the early stage of IVM stimulates preimplantation development of PA and SCNT porcine embryos by improving the cytoplasmic microenvironment. Mol. Reprod. Dev. 82: 489–497, 2015.

A simplified one-step nuclear transfer procedure alters the gene expression patterns and developmental potential of cloned porcine embryos

Various somatic cell nuclear transfer (SCNT) techniques for mammalian species have been developed to adjust species-specific procedures to oocyte-associated differences among species. Species-specific SCNT protocols may result in different expression levels of developmentally important genes that may affect embryonic development and pregnancy. In the present study, porcine oocytes were treated with demecolcine that facilitated enucleation with protruding genetic material. Enucleation and donor cell injection were performed either simultaneously with a single pipette (simplified one-step SCNT; SONT) or separately with different pipettes (conventional two-step SCNT; CTNT) as the control procedure. After blastocysts from both groups were cultured in vitro, the expression levels of developmentally important genes (OCT4, NANOG, EOMES, CDX2, GLUT-1, PolyA, and HSP70) were analyzed by real-time quantitative polymerase chain reaction. Both the developmental rate according to blastocyst stage as well as the expression levels CDX2, EOMES, and HSP70 were elevated with SONT compared to CTNT. The genes with elevated expression are known to influence trophectoderm formation and heat stress-induced arrest. These results showed that our SONT technique improved the development of SCNT porcine embryos, and increased the expression of genes that are important for placental formation and stress-induced arrest.

Improvement of pregnancy rate by intrauterine administration of dexamethasone and recombinant human leukemia inhibitory factor at the time of embryo transfer in cattle.

Bovine embryos (day 5) were cultured to day 10 with or without 100 ng/mL PGF2α in medium supplemented with control; 100 nM Dex; 1,000 U/mL recombinant human leukemia inhibitory factor (rhLIF); or Dex+rhLIF. Although the rates to development to the blastocyst were not significantly different among groups, the hatching rate after additional culture with Dex +/or rhLIF was significantly higher in all supplemented groups than the control (p < 0.05). In the presence of PGF2α, the hatching rate was significantly restored in all supplemented groups relative to the group treated with only PGF2α and the control (p < 0.05). Embryo transfer (ET) was performed with blastocysts (day 7). PGF2α levels of control recipient cows were significantly higher in the circulatory blood samples collected 60 min after ET than in samples collected 60 min before ET (p < 0.005), and were decreased in cows injected with loading medium supplemented with Dex+rhLIF (p < 0.005). Pregnancy rate was significantly higher in the ET group that received supplemented embryo-loading medium than in the non-supplemented control (p < 0.05). The intrauterine administration of Dex and rhLIF at ET prevented increased PGF2α in circulatory blood and resulted in enhanced pregnancy rate.