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An Analysis of the Geometrical and Optical Characteristics of Prisms Used in Elementary Schools
Jhun Youngseok 한국물리학회 2023 새물리 Vol.73 No.1
In this report, I describe investigations of the dispersive prisms used in elementary-school science classes to determine the extent to which they are uniform and accurate. As samples, I selected eight prisms that are widely used in schools, and I measured their refractive indices as functions of the wavelength of the light as well as their physical properties, such as shape and density. I measured the refractive index at each wavelength using a red He–Ne laser and yellow, green, and blue laser pointers. To ensure the precision of the measurements, I employed a threaded needle fixed to a stand as an indicator to determine the exact path of the light. In addition, rather than measuring the vertex, incident, and deviation angles directly, I obtained them by measuring the side lengths of a triangle drawn along the light path and then calculating the angles using the cosine law. As a result of this investigation, I found that prisms typically used in schools are neither right nor regular and that a variety of widely used materials—especially plastics—have varying densities and refractive index distributions. I also confirmed that some prisms had narrow dispersion, making it difficult to produce a clear spectrum.
Evidence for the Ras-Independent Signaling Pathway Regulating Insulin-Induced DNA Synthesis
Jhun, Byung-H. Korean Society for Biochemistry and Molecular Biol 1999 Journal of biochemistry and molecular biology Vol.32 No.2
The existence of the Ras-independent signal transduction pathway of insulin leading to DNA synthesis was investigated in Rat-1 fibroblasts overexpressing human insulin receptor (HIRc-B) using the single-cell microinjection technique. Microinjection of a dominant-negative mutant $Ras^{N17}$ protein into quiescent HIRc-B cells inhibited the DNA synthesis stimulated by insulin. Microinjection of oncogenic H-$Ras^{V12}$ protein ($H-Ras^{V12}$) (0.1 mg/ml) induced DNA synthesis by 35%, whereas that of control-injected IgG was induced by 20%. When the marginal amount of oncogenic H-$Ras^{V12}$ protein was coinjected with a dominant-negative mutant of the H-Ras protein ($Ras^{N17}$), DNA synthesis was 35% and 74% in the absence and presence of insulin, respectively. This full recovery of DNA synthesis by insulin suggests the existence of the Ras-independent pathway. The same recovery was observed in the cells coinjected with either H-$Ras^{V12}$ plus H-$Ras^{N17}$ plus SH2 domain of the p85 subunit of PI3-kinase ($p85^{SH2-N}$) or H-$Ras^{V12}$ plus H-$Ras^{N17}$ plus interfering anti-Shc antibody. When co-injected with a dominant-negative H-$Ras^{N17}$, the DNA synthesis induced by the Ras-independent pathway was blocked. These results indicate that the Ras-independent pathway of insulin leading to DNA synthesis exists, bypassing the p85 of PI3-kinase and Shc protein, and requires Rac1 protein.
Evidence for the Ras-Independent Signaling Pathway Regulating Insulin-Induced DNA Synthesis
Jhun, Byung H . 생화학분자생물학회 2000 BMB Reports Vol.32 No.2
The existence of the Ras-independent signal transduction pathway of insulin leading to DNA synthesis was investigated in Rat-1 fibroblasts overexpressing human insulin receptor (HIRc-B) using the single-cell microinjection technique. Microinjection of a dominant-negative mutant Ras^(N17) protein into quiescent HIRc-B cells inhibited the DNA synthesis stimulated by insulin. Microinjection of oncogenic HRas^(V12) protein (H-Ras^(V12)) (0.1 ㎎/㎖) induced DNA synthesis by 35%, whereas that of control-injected IgG was induced by 20%. When the marginal amount of oncogenic H-Ras^(V12) protein was coinjected with a dominant-negative mutant of the H-Ras^(V12) protein (H-Ras^(N17)), DNA synthesis was 35% and 74% in the absence and presence of insulin, respectively. This full recovery of DNA synthesis by insulin suggests the existence of the Ras-independent pathway. The same recovery was observed in the cells coinjected with either H-Ras^(V12) plus H-Ras^(V12) plus SH2 domain of the p85 subunit of PI3-kinase (p85^(SH2-N)) or H-Ras^(V12) plus H-Ras^(N17) plus interfering anti-Shc antibody. When coinjected with a dominant-negative Rac1^(N17), the DNA synthesis induced by the Ras-independent pathway was blocked. These results indicate that the Rasindependent pathway of insulin leading to DNA synthesis exists, bypassing the p85 of PI3-kinase and Shc protein, and requires Rac1 protein.
Jhun, Hyung-Joon,Seo, Hong-Gwan,Lee, Do-Hoon,Sung, Moon-Woo,Kang, Yoon-Dan,Syn, Hee Chul,Jun, Jong Kwan The Korean Academy of Medical Sciences 2010 JOURNAL OF KOREAN MEDICAL SCIENCE Vol.25 No.5
<P>This study examined urinary cotinine levels and self-reported smoking among pregnant women in Korea and the factors associated with smoking during pregnancy. The subjects were selected from pregnant women who visited 30 randomly sampled obstetric clinics and prenatal care hospitals in Korea in 2006. Smoking status was determined by self-reporting and urinary cotinine measurement. A total of 1,090 self-administered questionnaires and 1,057 urine samples were analyzed. The percentage of smoking revealed by self-reporting was 0.55% (95% confidence interval [CI], 0.11-0.99) and that revealed by urinary cotinine measurement (>100 ng/mL) was 3.03% (95% CI, 1.99-4.06). The kappa coefficient of agreement between self-reported smoking status and urinary cotinine measurement was 0.20 (95% CI, 0.03-0.37). Multiple logistic regression analysis revealed that early gestational period, low educational level, and being married to a smoker were significant risk factors for smoking during pregnancy. Smoking among pregnant women in Korea is not negligible, and those who are concerned to maternal and child health should be aware of this possibility among pregnant women in countries with similar cultural background.</P>
Evidence for the Ras-Independent Signaling Pathway Regulating Insulin-Induced DNA Synthesis
Jhun, Byung H. The Korea Science and Technology Center 1999 BMB Reports Vol.32 No.2
The existence of the Ras-independent signal transduction pathway of insulin leading to DNA synthesis was investigated in Rat-1 fibroblasts overexpressing human insulin receptor (HIRc-B) using the single-cell microinjection technique. Microinjection of a dominant-negative mutant Ras protein into quiescent HIRc-B cells inhibited the DNA synthesis stimulated by insulin. Microinjection of oncogenic H-Ras protein (H-Ras) (0.1㎎/ml) induced DNA synthesis by 35%, whereas that of control-injected IgG was induced by 20%. When the maginal amount of oncogenic H-Ras protein was coinjected with a dominant-negative mutant of the H-Ras protein(H-Ras), DNA synthesis was 35% and 74% in the absence and presence of insulin, respectively. This full recovery of DNA synthesis by insulin suggests the existence of the Ras-independent pathway. The same recovery was observed in the cells coinjected with either H-Ras H-Ras plus SH2 domain of the p85 subunit of PI3-kinase(p85) or H-Ras plus H-Ras plus interfering anti-Shc antibody. When coinjected with a dominant-negative Rac1, the DNA synthesis induced by the Ras-independent pathway was blocked. These results indicate that the Ras-independent pathway of insulin leading to DNA synthesis exists, bypassing the p85 of PI3-kinse and Shc protein, and requires Rac1 protein.