• 생태와환경
• /
• 제45권2호
• /
• pp.242-251
• /
• 2012

본 연구는 탄소 및 질소 안정동위원소비를 이용하여 하천에서 환경변화의 지표로 활용할 수 있는 부착조류의 먹이원으로서 기여도를 파악하고자 하였다. 연구지역인 탐진강은 지류를 통해 유입되는 외래기원물질의 영향으로 상류에서 하류로 갈수록 높은 영양염의 농도를 나타냈으며 이와 더불어 상위섭식자인 어류의 질소 안정동위원소비의 증가가 관찰되었다. 또한 탐진강에서 채집된 저서성대형무척추동물과 어류의 ${\delta}^{13}C$ 값이 상류에서 하류로 이동하면서 무거워지는 경향을 나타내었다. 이는 탐진강 하류 수역에서 무거운 ${\delta}^{13}C$ 값을 보였던 암석 부착조류가 먹이원으로서의 기여도가 높아진 결과로 판단된다.

• Journal of Ginseng Research
• /
• 제41권3호
• /
• pp.403-410
• /
• 2017

Background: Prenyltransferases catalyze the sequential addition of isopentenyl diphosphate units to allylic prenyl diphosphate acceptors and are classified as either trans-prenyltransferases (TPTs) or cis-prenyltransferases (CPTs). The functions of CPTs have been well characterized in bacteria, yeast, and mammals compared to plants. The characterization of CPTs also has been less studied than TPTs. In the present study, molecular cloning and functional characterization of a CPT from a medicinal plant, Panax ginseng Mayer were addressed. Methods: Gene expression patterns of PgCPT1 were analyzed by quantitative reverse transcription polymerase chain reaction. In planta transformation was generated by floral dipping using Agrobacterium tumefaciens. Yeast transformation was performed by lithium acetate and heat-shock for $rer2{\Delta}$ complementation and yeast-two-hybrid assay. Results: The ginseng genome contains at least one family of three putative CPT genes. PgCPT1 is expressed in all organs, but more predominantly in the leaves. Overexpression of PgCPT1 did not show any plant growth defect, and its protein can complement yeast mutant $rer2{\Delta}$ via possible protein-protein interaction with PgCPTL2. Conclusion: Partial complementation of the yeast dolichol biosynthesis mutant $rer2{\Delta}$ suggested that PgCPT1 is involved in dolichol biosynthesis. Direct protein interaction between PgCPT1 and a human Nogo-B receptor homolog suggests that PgCPT1 requires an accessory component for proper function.

• Mass Spectrometry Letters
• /
• 제10권1호
• /
• pp.11-17
• /
• 2019

Drosophila melanogaster (fruits fly) is a representative model system widely used in biological studies because its brain function and basic cellular processes are similar to human beings. The whole head of the fly is often used to obtain the key function in brain-related diseases like degenerative brain diseases; however the biomolecular distribution of the head may be slightly different from that of a brain. Herein, lipid profiles of the head and dissected brain samples of Drosophila were studied using electrospray ionization-mass spectrometry (ESI-MS). According to the sample types, the detection of phospholipid ions was suppressed by triacylglycerol (TAG), or the specific phospholipid signals that are absent in the mass spectrum were measured. The lipid distribution was found to be different in the wild-type and the microRNA-14 deficiency model ($miR-14{\Delta}^1$) with abnormal lipid metabolism. A few phospholipids were also profiled by comparison of the head and the brain in two fly model systems. The mass spectra showed that the phospholipid distributions in the $miR-14{\Delta}^1$ model and the wild-type were different, and principal component analysis revealed a correlation between some phospholipids (phosphatidylethanolamine (PE), phosphatidylinositol (PI), and phosphatidylserine (PS)) in $miR-14{\Delta}^1$. The overall results suggested that brain-related lipids should be profiled using fly samples after dissection for more accurate analysis.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제1권1호
• /
• pp.40-49
• /
• 2001

We have developed a repeatable process of forming uniform, small-size and high-density self-assembled Si nano-crystals. The Si nano-crystals were fabricated in a conventional LPCVD (low pressure chemical vapor deposition) reactor at $620^{\circ}c$ for 15 sec. The nano-crystals were spherical shaped with about 4.5 nm in diameter and density of $5{\times}l0^{11}/$\textrm{cm}^2$. More uniform dots were fabricated on nitride film than on oxide film. To take advantage of the above-mentioned characteristics of nitride film while keeping the high interface quality between the tunneling dielectrics and the Si substrate, nitride-oxide tunneling dielectrics is proposed in n-channel device. For the first time, the single electron effect at room temperature, which shows a saturation of threshold voltage in a range of gate voltages with a periodicity of ${\Delta}Ｖ_{GS}\;{\approx}\;1.7{\;}V$, corresponding to single and multiple electron storage is reported. The feasibility of p-channel nano-crystal memory with thin oxide in direct tunneling regime is demonstrated. The programming mechanisms of p-channel nano-crystal memory were investigated by charge separation technique. For small gate programming voltage, hole tunneling component from inversion layer is dominant. However, valence band electron tunneling component from the valence band in the nano-crystal becomes dominant for large gate voltage. Finally, the comparison of retention between programmed holes and electrons shows that holes have longer retention time.

• Bulletin of the Korean Chemical Society
• /
• 제25권2호
• /
• pp.271-279
• /
• 2004

The aroma component of Hallabong peel has been characterized by GC-MS with two different extraction techniques: solid-phase trapping solvent extraction (SPTE) and headspace solid-phase microextraction (HSSPME). Aroma components emitted from Hallabong peel were compared with those of other citrus varieties: lemon, orange and grapefruit by SPTE and GC-MS. d-Limonene (96.98%) in Hallabong was the main component, and relatively higher peaks of cis- ${\beta}$-ocimene, valencene and -farnesene were observed. Other volatile aromas, such as sabinene, isothujol and ${\delta}$-elemene were observed as small peaks. Also, principal components analysis was employed to distinguish citrus aromas based on their chromatographic data. For HSSPME, the fiber efficiency was evaluated by comparing the partition coefficient ($K_{gs}$Kgs) between the HS gaseous phase and HS-SPME fiber coating, and the relative concentration factors (CF) of the five characteristic compounds of the four citrus varieties. 50/30 ${\mu}$m DVB/CAR/PDMS fiber was verified as the best choice among the four fibers evaluated for all the samples.

• 한국결정성장학회지
• /
• 제16권5호
• /
• pp.203-209
• /
• 2006

For $P_B=50,\;{\Delta}T=10K$, Ar=5, Pr=2.36, Le=0.015, Pe=1.26, Cv=1.11, the intensity of solutal convection (solutal Grashof number $Grs=3.44x10^4$) is greater than that of thermal convection (thermal Grashof number $Grt=1.81x10^3$) by one order of magnitude, which is based on the solutally buoyancy-driven convection due to the disparity in the molecular weights of the component A($Hg_2Cl_2$) and B(He). With increasing the partial pressure of component B from 10 up to 200 Torr, the rate is decreased exponentially. The convective transport decreases with lower g level and is changed to the diffusive mode at 0.1 $g_0$. In other words, for regions in which the g level is 0.1 $g_0$ or less, the diffusion-driven convection results in a parabolic velocity profile and a recirculating cell is not likely to occur. Therefore a gravitational acceleration level of less than 0.1 $g_0$ can be adequate to ensure purely diffusive transport.

• 한국세라믹학회지
• /
• 제49권1호
• /
• pp.56-65
• /
• 2012

Functional materials are often exposed to high temperatures and inherent temperature gradients. These temperature gradients act as thermodynamic driving forces for the diffusion of mobile components. The detailed consequences of thermodiffusion depend on the boundary conditions of the non-isothermal sample: Once the boundaries of the sample are inert and closed for exchange of the mobile components, thermodiffusion leads to their pile-up in the stationary state (the so called Soret effect). Once the system is open for an exchange of the mobile component, chemical diffusion adds to the Soret effect, and stationary non-zero component fluxes are additionally observed in the stationary state. In this review, the essential aspects of thermodiffusion and Soret effect in inorganic functional materials are briefly summarized and our current practical knowledge is reviewed. Major examples include nonstoichiometric binary compounds (oxides and other chalcogenides) and ternary solid solutions. The potential influence of the Soret effect on the long term stability of high temperature thermoelectrics is briefly discussed. Typical Soret coefficients for nonstoichiometric compounds are found to be of the order of (d${\delta}$/dT) ${\approx}$ 1%/K.

• 한국시뮬레이션학회논문지
• /
• 제9권4호
• /
• pp.51-58
• /
• 2000

The control of the data retention time is a main issue for realizing future high density dynamic random access memory. The novel junction process scheme in sub-micron DRAM cell with STI(Shallow Trench Isolation) has been investigated to improve the tail component in the retention time distribution which is of great importance in DRAM characteristics. In this' paper, we propose the new implantation scheme by gate-related ion beam shadowing effect and buffer-enhanced ${\Delta}Rp$ (projected standard deviation) increase using buffered N-implantation with tilt and 4X(4 times)-rotation that is designed on the basis of the local-field-enhancement model of the tail component. We report an excellent tail improvement of the retention time distribution attributed to the reduction of electric field across the cell junction due to the redistribution of N-concentration which is Intentionally caused by ion Beam Shadowing and Buffering Effect using tilt implantation with 4X-rotation. And also, we suggest the least requirements for adoption of this new implantation scheme and the method to optimize the key parameters such as tilt angle, rotation number, Rp compensation and Nd/Na ratio. We used MEDICI Simulator to confirm the junction device characteristics. And measured the refresh time using the ADVAN Probe tester.

• 한국식품과학회지
• /
• 제35권4호
• /
• pp.648-652
• /
• 2003

본 실험은 순수참기름과 혼합참기름의 구별 및 순도판별을 용이하게 하기 위한 분석방법을 제시하고자 실행되었다. 순수참기름과 옥수수기름을 95 : 5, 90 : 10, 80 : 20(w/w)의 비율로 각각 비율을 달리해서 혼합참기름을 제조한 후 GC, SPME-GC/MS, 전자코를 이용한 분석을 실시하였다. 지방산조성(mole%)을 비교한 결과 옥수수기름이 10%이상 함유된 혼합참기름과 순수참기름 간에는 stearic acid와 linoleic acid의 함량의 변화로 구별이 가능하였으나 5%내로 옥수수유가 함유된 혼합참기름과 순수참기름과의 구별은 용이하지 않았다. 향기성분동정을 위해 SPME-GC/MS 분석을 실시한 결과순수참기름과 혼합참기름은 같은 향기성분 패턴을 보여 구별하기 어려웠다. 반면, MOS 유형의 전자코를 이용하여 향기성분패턴 분석결과 제1주성분 값의 기여율이 98.76%로 구별이 가능하였으며 이로써 신속하고 편리하게 비파괴적 분석 방법인 전자코를 활용하여 순수참기름과 혼합참기름을 구별할 수 있었다.

• 한국결정성장학회지
• /
• 제17권6호
• /
• pp.256-263
• /
• 2007

For $P_B=50Torr,\;P_T=5401Torr,\;T_S=450^{\circ}C,\;{\Delta}T=20K$, Ar=5, Pr=3.34, Le=0.01, Pe=4.16, Cv=1.05, adiabatic and linear thermal profiles at walls, the intensity of solutal convection (solutal Grashof number $Grs=7.86{\times}10^6$) is greater than that of thermal convection (thermal Grashof number $Grt=4.83{\times}10^5$) by one order of magnitude, which is based on the solutally buoyancy-driven convection due to the disparity in the molecular weights of the component A ($Hg_2Cl_2$) and B (He). With increasing the partial pressure of component B from 20 up to 800 Torr, the rate is decreased exponentially. It is also interesting that as the partial pressure of component B is increased by a factor of 2, the rate is approximately reduced by a half. For systems under consideration, the rate increases linearly and directly with the dimensionless Peclet number which reflects the intensity of condensation and sublimation at the crystal and source region. The convective transport decreases with lower g level and is changed to the diffusive mode at $0.1g_0$. In other words, for regions in which the g level is $0.1g_0$ or less, the diffusion-driven convection results in a parabolic velocity profile and a recirculating cell is not likely to occur. Therefore a gravitational acceleration level of less than $0.1g_0$ can be adequate to ensure purely diffusive transport.