• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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• pp.8093-8100
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• 2016

Background: Genetic and environmental factors play important roles in pathogenesis of digestive tract cancers like those in the esophagus, stomach and colorectum. Folate deficiency and methylenetetrahydrofolate reductase (MTHFR) as an important enzyme of folate and methionine metabolism are considered crucial for DNA synthesis and methylation. MTHFR variants may cause genomic hypomethylation, which may lead to the development of cancer, and MTHFR gene polymorphisms (especially C677T and A1298C) are known to influence predispositions for cancer development. Several case control association studies of MTHFR C677T polymorphisms and colorectal cancer (CRC) have been reported in different populations with contrasting results, possibly reflecting inadequate statistical power. Aim: The present meta-analysis was conducted to investigate the association between the C677T polymorphism and the risk of colorectal cancer. Materials and Methods: A literature search of the PubMed, Google Scholar, Springer link and Elsevier databases was carried out for potential relevant articles. Pooled odds ratio (OR) with corresponding 95 % confidence interval (95 % CI) was calculated to assess the association of MTHFR C677T with the susceptibility to CRC. Cochran's Q statistic and the inconsistency index (I2) were used to check study heterogeneity. Egger's test and funnel plots were applied to assess publication bias. All statistical analyses were conducted by with MetaAnalyst and MIX version 1.7. Results: Thirty four case-control studies involving a total of 9,143 cases and 11,357 controls were retrieved according to the inclusion criteria. Overall, no significant association was found between the MTHFR C677T polymorphism and colorectal cancer in Asian populations (for T vs. C: OR=1.03; 95% CI= 0.92-1.5; p= 0.64; for TT vs CC: OR=0.88; 95%CI= 0.74-1.04; p= 0.04; for CT vs. CC: OR = 1.02; 95%CI= 0.93-1.12; p=0.59; for TT+ CT vs. CC: OR=1.07; 95%CI= 0.94-1.22; p=0.87). Conclusions: Evidence from the current meta-analysis indicated that the C677T polymorphism is not associated with CRC risk in Asian populations. Further investigations are needed to offer better insight into any role of this polymorphism in colorectal carcinogenesis.

• Asian Pacific Journal of Cancer Prevention
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• 제16권7호
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• pp.2725-2729
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• 2015

Background: Transitional cell carcinoma (TCC) and prostate cancer are the most frequent cancers in the male genitourinary tract. Measurement of biological biomarkers may facilitate clinical monitoring and aid early diagnosis of TCC. The aim of the present investigation was to detect the mRNA levels of S100A12 and RAGE (receptor for advanced glycation end products) in patients suffering from bladder TCC. Materials and Methods: To explore the involvement of S100A12 and RAGE genes, total RNA was harvested from cancer tissues and samples obtained from normal non-tumorized urothelium of the same patients. Quantitative PCR (qPCR) was subsequently employed to determine the mRNA levels of S100A12 and RAGE. Results: The results showed that mRNA expression of S100A12 and RAGE was significantly up-regulated in the cancer tissue. Conclusions: According to the results presented in the current study, mRNA expression of S100A12 and RAGE might be as a useful biomarker for TCC. Therefore, this ligand-receptor axis possibly plays important roles in the development of TCC and may serve either as an early diagnostic marker or as a key factor in monitoring of response to treatment. More research is required concerning inhibition of the S100A12-RAGE axis in different cancer models.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제20권9호
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• pp.961-966
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• 2009

In this paper, a novel voltage-controlled oscillator(VCO) using the metamaterial broadside coupled spiral resonators(BC-DSRs) is presented for reducing the phase noise. For reducing of the phase noise, the series spiral structures have been applied for the signal plane and ground plane at each in order to have the large coupling. Compared with the conventional VCO, the proposed VCO has the larger coupling coefficient constant, which makes a higher Q-factor and has reduced the phase noise of the VCO. The proposed VCO has the phase noise of $-121{\sim}-117.16\;dBc$/Hz at 100 kHz in the tuning range, $5.749{\sim}5.853\;GHz$. The figure of merit(FOM) of this VCO is $-198.45{\sim}-194.77\;dBc$/Hz at 100 Hz in the same tuning range, respectively.

• Journal of the Korean Ceramic Society
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• 제52권1호
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• pp.77-82
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• 2015

The effect of the electrode type on the dielectric and piezoelectric properties of $Pb(Mg_{1/3}Nb_{2/3})O_3-PbZrO_3-PbTiO_3$ (PMN-PZT) single crystals was investigated in an effort to improve their properties for various piezoelectric applications. First, three different types of PMN-PZT single crystals [PMN-PZT-A (piezoelectrically soft type; dielectric constant ~ 10,000), PMN-PZT-B (piezoelectrically soft type; phase-transition temperature between the rhombohedral and tetragonal phases ($T_{RT}$) ~ $145^{\circ}C$), PMN-PZT-C (piezoelectrically hard type; high mechanical quality factor ($Q_m$) ~ 1,000)] were fabricated using the solid-state single crystal growth (SSCG) method. Then, four different types of electrodes [sputtered Au, sputtered Cr/Au, sputtered Ti/Au, and fired Ag] were formed on the single crystals, and their dielectric and piezoelectric properties were measured. The single crystals with a sputtered Ti/Au electrode showed the highest dielectric and piezoelectric constants but the lowest coercive electric field ($E_C$). The single crystals with a fired Ag electrode showed the lowest dielectric and piezoelectric constants but the highest coercive electric field ($E_C$). This dependence on the type of electrode was most significant in the piezoelectrically hard PMN-PZT-C single crystals. However, the effects of the electrode type on the phase transition temperatures ($T_C$, $T_{RT}$) and dielectric loss were negligible. These results clearly demonstrate that it is important to select an appropriate electrode so as to maximize the dielectric and piezoelectric properties of single crystals in each type of piezoelectric application.

• Journal of the Korean Ceramic Society
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• 제55권2호
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• pp.166-173
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• 2018

In order to investigate the effect of Mn on the dielectric and piezoelectric properties of PMN-PT [$Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3$], four different types of 71PMN-29PT samples were prepared using the solid-state single crystal growth (SSCG) method: (1) Undoped single crystals, (2) undoped polycrystalline ceramics, (3) Mn-doped single crystals, and (4) Mn-doped polycrystalline ceramics. In the case of single crystals, the addition of 0.5 mol% Mn to PMN-PT decreased the dielectric constant ($K_3{^T}$), piezoelectric charge constant ($d_{33}$), and dielectric loss (tan ${\delta}$) by about 50%, but increased the coercive electric field ($E_C$) by 50% and the electromechanical quality factor ($Q_m$) by 500%, respectively. The addition of Mn to PMN-PT induced an internal bias electric field ($E_I$) and thus specimens changed from piezoelectrically soft-type to piezoelectrically hard-type. This Mn effect was more significant in single crystals than in ceramics. These results demonstrate that Mn-doped 71PMN-29PT single crystals, because they are piezoelectrically hard and simultaneously have high piezoelectric and electromechanical properties, have great potential for application in fields of SONAR transducers, high intensity focused ultrasound (HIFU), and ultrasonic motors.

• Journal of Korean Academy of Nursing
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• 제30권1호
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• pp.137-147
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• 2000

The purpose of this study was to investigate characteristics of teenagers' perceptions to bullies according to the classification types of Q-methodology. The results of the analysis were classified in 5 types. Type 1, which was the type geared foward solution, showed that they expressed a strong attitude of sympathy and protection towards the victim. However, they had harbored rage and hostile feelings against the assaulter. For example, when they witnessed the bully in action, they positively intervened in the situation. Type 2, which was the observer type, showed that they thought the victims were to blame for their misfortune. Also, when a friend who was left out in the cold by his classmates, they were just watched without showing any special interest. Type 3, which was the type of conflict, indicated that they believed that the both the victim and the assaulter should have responsibility. In contrast to the previous type, they had sympathy for the friend who was left out in the cold by his classmates, they had the dual feeling that intended to use the bully under the situation with his friend. Type 4, which was the type of assenting, indicated that they assumed an indifferent attitude to the situation, while they implied assenting to the situation of the friend who had a bad relationship with them. Type 5, which was the negative type, showed that they had the negative view to the situation of bully itself so that they did not recognize the bully as the method of revenge for whatever reason. The results of the study showed that the bully increased the factor of stress to school life of the victim or assaulter, even in the subjective position. The perception of the bully should change according to the characteristics of the types of people and it is necessary to study how to cope with the situations.

• Korean Journal of Child Studies
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• 제13권2호
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• pp.217-228
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• 1992

The purpose of this study is to examine the effects of early full-time nonparental care during infancy/toddlerhood on children's socioemotional behaviors during the preschool period. Subjects for this study were 105 three- to five-year-olds from middle-class families in the U. S. A. Children were assigned to one of three groups according to their early care history. Children's social interactions with peers and caregivers during indoor free-play sessions in day care centers were observed for 20 minutes. The head teachers rated the children's social and emotional behaviors on two questionnaires. Mothers completed the Attachment Q-sort for attachment assessment for the preschoolers. In addition, mothers were asked to fill out a questionnaire on their parenting practices. Children who had received full-time nonparental care during infancy and/or toddlerhood were rated by their teachers as being more intellectually competent than children who did not receive full-time nonparental care during first three years of life. They were, however, rated by teachers and were observed by the researcher as being more aggressive than children with no full-time nonparental care. These children were observed to engage in less wandering/onlooking behaviors than children who had not had any full-time nonparental care. Children's attachment security scores and dependency scores did not differ as a function of early nonparental care histories. When the effects of early care patterns, sex of child, and current attachment security to mothers on aggressive behaviors of the preschoolers were examined by a hierarchical regression model, then any "pure" effects of nonparental care and of attachment security on child aggression were minimal after controlling for family background, child care center quality, and maternal childrearing practices. Strong buffering factors for the preschool children (family characteristics, parenting styles, and high quality nonparental care) mediated a possible risk factor of early nonparental care and promoted optimal outcomes for the children.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.131-134
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• 2002

The effect of the addition on the densification, low temperature sintering, and microwave dielectric properties of the Ca[($Li_{1/3}Nb_{2/3}$)$_{1-x}$$Ti_{x}$]$O_{3-{\delta}}$/(CLNT) was investigated. $Bi_2O_3$ additives improved the dencification and reduced the sintering temperature from $1150^{\circ}C$ to $900^{\circ}C$ of CLNT microwave dielectric ceramics. As increasing $Bi_2O_3$ contents, the dielectric constants and bulk density were increased. The quality factor, however, was decreased slighty. The temperature coefficients of the resonant frequency shifted positive value as increasing $Bi_2O_3$ contents. The dielectric properties of Ca[($Li_{1/3}Nb_{2/3}$)$_{1-x}$$Ti_{x}$]$O_{3-{\delta}}$ and Ca[($Li_{1/3}Nb_{2/3}$)$_{0.8}Ti_{0.2}$]$O_{3-{\delta}}$ with 5wt% $Bi_2O_3$ sintered at $900^{\circ}C$ for 3h were $\varepsilon_{r}$=20, 35 Q.$f_{0}$=6500, 11,000 GHz, $\tau_{f}$=4, 13 ppm/$^{\circ}C$, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제17권8호
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• pp.840-845
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• 2004

The microstructure and microwave dielectric properties of $(1-x){Mg}_4{Ta}_2{O}_9-xTi{O}_2(x=0\sim0.9)$ ceramics were investigated. The specimens were prepared by the conventional mixed oxide method with sintering temperature of 140$0^{\circ}C$∼150$0^{\circ}C$. To improve the quality factor and the temperature coefficient of resonant frequency,$ Ti{O}_2(\varepsilon\Gamma=100, Q\times f_\Gamma=40,000 GHz,\ta_f= +450 ppm\diagup^{\circ}C $ was added in ${Mg}_4{Ta}_2{O}_9$ceramics. The dielectric and structural properties were investigated. According to the XRD patterns, $(1-x){Mg}_4{Ta}_2{O}_9-xTi{O}_2(x=0\sim0.9)$ ceramics had the ${Mg}_4{Ta}_2{O}_9$ phase(hexagonal) and ${MgTi}_2{O}_5$phase(orthorhombic). The dielectric constant($\varepsilon_r$). quality($Qtimes{f}_r$${\tau}_f$) of the $(1-x){Mg}_4{Ta}_2{O}_9-xTi{O}_2(x=0\sim0.9)$ ceramics were 8.12∼18.59, 18,750∼186,410 GHz and －36.02∼＋3.46 ppm/$^{\circ}C$, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제25권7호
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• pp.516-520
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• 2012

In this paper, we have theoretically analyzed and designed a dielectric multi-layer sensor with a SPR (surface plasmon resonance) using analytical calculation and FDTD (finite difference time-domain) methods. The proposed structure is composed of periodic layer and thin metal film. It has many advantages. One of that is a high sensitivity of the SPR. Another is a high Q-factor of the characteristics in the PhC (photonic crystals) micro-cavity structure. The incident light has double resonance characteristics, because the filtered light by PhC structure, dielectric multi-layer, is met the thin metal film for SPR effect. We have also observed the change of resonance characteristics according to the variation of effective index on the metal film.