• Biomolecules & Therapeutics
• /
• v.26 no.3
• /
• pp.313-321
• /
• 2018

Anti-cancer drug resistance is a major problem in colorectal cancer (CRC) research. Although several studies have revealed the mechanism of cancer drug resistance, molecular targets for chemotherapeutic combinations remain elusive. To address this issue, we focused on the expression of cellular prion protein ($PrP^C$) in 5-FU-resistant CRC cells. In 5-FU-resistant CRC cells, $PrP^C$ expression is significantly increased, compared with that in normal CRC cells. In the presence of 5-FU, $PrP^C$ increased CRC cell survival and proliferation by maintaining the activation of the PI3K-Akt signaling pathway and the expression of cell cycle-associated proteins, including cyclin E, CDK2, cyclin D1, and CDK4. In addition, $PrP^C$ inhibited the activation of the stress-associated proteins p38, JNK, and p53. Moreover, after treatment of 5-FU-resistant CRC cells with 5-FU, silencing of $PrP^C$ triggered apoptosis via the activation of caspase-3. These results indicate that $PrP^C$ plays a key role in CRC drug resistance. The novel strategy of combining chemotherapy with $PrP^C$ targeting may yield efficacious treatments of colorectal cancer.

• Polymer(Korea)
• /
• v.36 no.6
• /
• pp.693-698
• /
• 2012

In this study aluminum isopropyl oxide ($Al(O-i-Pr)_3$) was supported on the amine-functionalized surface of silica to synthesize high molecular weight (MW) polylactide (PLA), and it was tested for PLA polymerization behaviors. A silica was funtionalized with silane compound having amine groups, then in-situ treated with $Al(O-i-Pr)_3$. $Al(O-i-Pr)_3$ attached to amine group on silica showed activity only in the presence of MAO (methyl aluminoxane). At the polymerization temperature of $115^{\circ}C$, the conversion and the MW of PLA were increased as the amount of silane was increased. At the polymerization temperature of $130^{\circ}C$, the conversion was decreased while the MW was increased drastically and reached to MW 44000 g/mol when the amine concentration was 3.0 mmol/g. A bimodal type GPC curve was shown at the polymerization temperature of $115^{\circ}C$. As the amount of amine group increased, the peaks of GPC curve were merged. At the polymerization of $130^{\circ}C$, a unimodal GPC curve was shown. $Al(O-i-Pr)_3$ supported on amine-functionalized silica was able to produce higher MW PLA with enhanced activity compared to homogeneous $Al(O-i-Pr)_3$.

• Journal of the Korean Ceramic Society
• /
• v.48 no.2
• /
• pp.183-188
• /
• 2011

In this article, the effect of the crystal structural environment of $Pr^{3+}$ ions on the photoluminescence (PL) characteristics of double tungstates, such as $A(M_{1-X}Pr_X)W_2O_8$ (A=Li, Cs, M = In, Y, Sc, La; $0.007{\leq}x{\leq}0.1$) and $La_{1.96}Pr_{0.04}W_3O_{12}$ are characterized. By varying the ion radius in A and M sites, the structural environment of $Pr^{3+}$ ions were modified. The structural criteria, that is, the point charge electrostatic potentials V around the $Pr^{3+}$ activator, were calculated using the crystal structural parameters. The point charge potential V can be a valid criterion for $^3P_o$ quenching in various double tungstates. When the calculated V values are large (> 6.0), the luminescence from the $^3P_0$ level becomes dominant. When the calculated V values are about 3.8, the $^1D_2$ line appears weakly but $^3P_0$-level luminescence is absent. When the calculated V values are small (< 2.0), the luminescence from the $^1D_2$ level becomes dominant and $^3P_0$-level luminescence is absent. At 2.0$^3P_o$ quenching to $^1D_2$ level occurs substantially in accordance with the structural criterion of the point charge potential model.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.22 no.3
• /
• pp.360-372
• /
• 1998

This study deals with the interaction between buoyancy-induced convection and externally imposed excitation in the form of harmonic rocking and the effect of the interaction upon heat transfer in low-Pr liquids. A wide array of system responses are discussed using the spectral collocation numerical technique. The superposition of buoyancy and Coriolis forces leads to complex fluid flow and heat transfer. The transition to chaotic convection is accelerated, and heat transfer rates are reduced as the enclosure is excited at the fundamental frequency of oscillation associated with the pure buoyancy-driven case. Average heat transfer rates are correlated for Pr=0.02 and 0.03. The heat transfer is affected more in the Pr=0.03 liquid than the case of Pr=0.02.

• Journal of Venture Innovation
• /
• v.3 no.2
• /
• pp.129-145
• /
• 2020

The purpose of this study was to examine the effects of the job characteristics of the PR practitioner on flourishing and to identify the mediating effect of the meaning of work and job engagement. This study used a survey of 353 PR practitioners from PR firms and the hypothesis was verified by gathering the data of the job characteristics, the meaning of work, the job engagement and the flourishing by conducting hierarchical regression analysis and SPSS Process Macro bootstrapping analysis. The results showed that the job characteristics of the PR practitioner were found to influence the flourishing with the double-mediation effect, the meaning of the work and job engagement. The more PR practitioners regard their work affects their surroundings, the higher the degree of autonomy is, and the more they get feedbacks they engaged more, as they valued their job more thereby experience flourish more. Moreover, when PR practitioners valued their job more, they more engaged in their work and experience flourish. The meaning of work revealed to be the important factor to affect flourish regardless of the job characteristics and the job engagement so that gained the results that PR firms' effort to elevate the meaning of work of PR practitioners has is important. The study findings suggest that PR practitioners' flourishing is manageable in the organization by paying attention to oneself in the aspect of the organization, not leaving in individual areas. Limitaions and implications for future studies were discussed.

• Proceedings of the Optical Society of Korea Conference
• /
• 2008.02a
• /
• pp.403-405
• /
• 2008

Solid state lighting 용 적색 형광체로 적용하기 위하여 $BaTiO_3$:$Pr^{3+}$:$Ga^{3+}$를 다음과 같이 합성하였다. 출발 물질로 $BaCO_3$,$Pr(NO_3)_3$ $6H_2O$, $TiO_2$, $Ga_2O_3$을 사용 하였으며, $BaTiO_3$:$Pr^{3+}\;_x$(x=$0.001{\sim}0.2$):$Ga^{3+}\;_y$(y=0.05, 0.1, 0.5 1, 2, 3)를 각각의 조성대로 혼합한 후 $600^{\circ}C$에서 10시간 전처리 하였다. 전처리한 시료를 시편으로 제조하여 $1200^{\circ}C$ 공기중에 4시간 소성하여 최종물질인 $BaTiO_3$:$Pr^{3+}\;_x$:$Ga^{3+}\;_y$을 얻었다. 이 화합물을 X-선 회절 분석 결과 공간군 P4MM을 갖는 페로브스카이트임을 알 수 있었다. 이 화합물을 적색형광체로 적용하기 위해 PL과 PLE측정을 통하여 형광특성을 알아본 결과 618nm에서 x=0.011, y=1.0 일 때 특성이 가장 우수한 것으로 나타났다.

• Journal of the Korean Ceramic Society
• /
• v.38 no.2
• /
• pp.107-111
• /
• 2001

Sr$_{(1-x)}$Ca$_{x}$TiO$_3$: Pr$^{3+}$ , Ga$^{3+}$ (0$\leq$x$\leq$1) 형광체의 여기 및 발광 스펙트럼과 분광 반사율을 조사하여 발광 메커니즘을 규명하고자 하였다. 발광 스펙트럼에서는 611~614nm 사이에서 peak을 가지는 하나의 적색 발광 밴드가 관찰되었으며, 조성에 따라 발광밴드의 모양이 달랐다. 이는 조성에 따른 모체의 결정 구조 변화 때문으로 생각된다. 여기 스펙트럼 끝단과 분광 반사율 스펙트럼의 흡수단은 서로 일치하였으며, 이 결과로부터 모체에 흡수된 에너지가 Pr$^{3+}$ 에 전달되어 적색광을 방출하는 것이 주된 메커니즘으로 생각된다. 한편 120$0^{\circ}C$에서 4시간동안 열처리하여 합성한 Sr$_{0.4}$Ca$_{0.6}$TiO$_3$:(0.1 mol%)Pr$^{3+}$ , (0.2 mol%)Ga$^{3+}$ 는 우수한 색순도와 휘도를 나타내었다.다.

• Journal of the Semiconductor & Display Technology
• /
• v.17 no.4
• /
• pp.37-41
• /
• 2018

$Y_3A_{l5}O_{12}:Ce^{3+},Pr^{3+}$ single crystal phosphor was prepared by floating zone method. single crystal was confirmed to have a Ia-3d (230) space group of cubic structure and showed regular morphology. The optical properties, single crystal exhibited a emission band from green, yellow wide wavelength and 610nm, 640nm red wavelength vicinity. The luminance maintenance rate was decreased by phonon with increasing temperature, but high luminance is maintained more than powder phosphor. In addition, $Y_3A_{l5}O_{12}:Ce^{3+},Pr^{3+}$ single crystal phosphor was applied to a high power blue laser diode, we implemented high power white laser lightings. and it was confirmed that thermal properties over time, due to the effective heat transfer of complete crystal structure. We confirmed that excellent radiant heat properties than powder phosphor was applied to a high power white laser diode.

• The Transactions of the Korea Information Processing Society
• /
• v.3 no.1
• /
• pp.63-76
• /
• 1996

In this paper, we propose a new dynamic spatial index structure, called PR -file, for handling spatial objects and the modified hierarchical variance which measures the degree of spatial locality at each level. Under the assumption that a multidimensional search space has a circular domain, PR-file uses the modified hierarchical variance for clustering spatially adjacent objects. The insertion and splitting algorithms of PR_file preserve and index which has a low hierarchical variance regardless of object distributions. The simulation result shows that PR- file has a high hit ratio during a retrieval of objects by using an index with low hierarchical variance. And it shows a characteristic that the larger the bucket capacity, the higher the bucket utilization.

• Journal of Biomedical and Translational Research
• /
• v.19 no.4
• /
• pp.73-78
• /
• 2018

Osteoporosis is a major worldwide public health problem that poses a great economic burden to society. Puerariae Radix, the dried root of Pueraria lobata (Wild.) Ohwi, has been widely used in Asia. This study investigated the effects of Puerariae Radix (PR) on bone loss in ovariectomized (OVX) mice. C3H/HeN mice (10 weeks old) were divided into sham and OVX groups. The OVX mice were treated with vehicle, $17{\beta}-estradiol$ ($E_2$), PR (oral administration, 250 mg/kg/day) or PR (intraperitoneal administration, 50 mg/kg/every other day) for 6 weeks. Grip strength, uterus weight, serum alkaline phosphatase (ALP), estradiol concentration and osteoclast surface levels were measured. Tibiae were analyzed using microcomputed tomography. There were no significant differences in the degree of grip strength, body weight and uterine weight between OVX group and PR-treated group. As compared with the OVX group, the serum estradiol levels were significantly increased in the PR-treated group. PR (i.p.) significantly preserved trabecular bone volume, trabecular bone number, structure model index and bone mineral density of proximal tibiae metaphysic. The administration of PR lowered serum ALP and osteoclast surface levels in OVX mice, suggesting that PR can reduce the bone turnover rate in mice. The results indicate that the supply of PR can prevent OVX-induced bone loss in mice.