Relationship Between K_trans and K₁ with Simultaneous Versus Separate MR/PET in Rabbits with VX2 Tumors

Lee, K. H.,Kang, S. K.,Goo, J. M.,Lee, J. S.,Cheon, G. J.,Seo, S.,Hwang, E. J. INTERNATIONAL INSTITUTE OF ANTICANCER RESEARCH 2017 Anticancer research Vol.37 No.3

<P>Background/Aim: To compare the relationship between Ktrans from DCE-MRI and K1 from dynamic (NNH3)-N-13- PET, with simultaneous and separate MR/PET in the VX-2 rabbit carcinoma model. Materials and Methods: MR/PET was performed simultaneously and separately, 14 and 15 days after VX-2 tumor implantation at the paravertebral muscle. The Ktrans and K-1 values were estimated using an in-house software program. The relationships between Ktrans and K-1 were analyzed using Pearson's correlation coefficients and linear/non-linear regression function. Results: Assuming a linear relationship, Ktrans and K-1 exhibited a moderate positive correlations with both simultaneous ( r=0.54-0.57) and separate ( r=0.53-0.69) imaging. However, while the Ktrans and K-1 from separate imaging were linearly correlated, those from simultaneous imaging exhibited a non-linear relationship. The amount of change in K-1 associated with a unit increase in Ktrans varied depending on Ktrans values. Conclusion: The relationship between K-trans and K-1 may be mis-interpreted with separate MR and PET acquisition.</P>

Solubility of oxcarbazepine in eight solvents within the temperature range T=(288.15-308.15)K

Nam, K.,Ha, E.S.,Kim, J.S.,Kuk, D.H.,Ha, D.H.,Kim, M.S.,Cho, C.W.,Hwang, S.J. Academic Press 2017 The Journal of chemical thermodynamics Vol.104 No.-

In this study, the solubility of oxcarbazepine in pure methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, acetone, acetonitrile, and tetrahydrofuran was analysed across the temperature range of 288.15-308.15K under atmospheric pressure by using a solid-liquid equilibrium method. The experimental values obtained data were correlated using the modified Apelblat model at each temperature. The mole fraction solubility of oxcarbazepine in all eight pure solvents increased gradually in a temperature-dependent manner. The highest mole fraction solubility of 3.08x10<SUP>-3</SUP> at 308.15K was observed for tetrahydrofuran, followed by acetone (1.82x10<SUP>-3</SUP> at 308.15K), acetonitrile (1.22x10<SUP>-3</SUP> at 308.15K), methanol (1.11x10<SUP>-3</SUP> at 308.15K), ethanol (6.17x10<SUP>-4</SUP> at 308.15K), 1-butanol (6.17x10<SUP>-4</SUP> at 308.15K), 1-propanol (6.16x10<SUP>-4</SUP> at 308.15K), and 2-propanol (4.13x10<SUP>-4</SUP> at 308.15K). The experimental solubility in all solvents correlated well with that calculated using the modified Apelblat equation across the temperature range of (288.15-308.15)K. Therefore, the experimental solubility and correlation equations established in this study could be useful during the crystallization/purification, pre-formulation, and formulation stages of oxcarbazepine production in laboratories and related industries.

Novel signaling axis for ROS generation during K-Ras-induced cellular transformation

Park, M-T,Kim, M-J,Suh, Y,Kim, R-K,Kim, H,Lim, E-J,Yoo, K-C,Lee, G-H,Kim, Y-H,Hwang, S-G,Yi, J-M,Lee, S-J Macmillan Publishers Limited 2014 CELL DEATH AND DIFFERENTIATION Vol.21 No.8

Reactive oxygen species (ROS) are well known to be involved in oncogene-mediated cellular transformation. However, the regulatory mechanisms underlying ROS generation in oncogene-transformed cells are unclear. In the present study, we found that oncogenic K-Ras induces ROS generation through activation of NADPH oxidase 1 (NOX1), which is a critical regulator for the K-Ras-induced cellular transformation. NOX1 was activated by K-Ras-dependent translocation of p47<SUP>phox</SUP>, a subunit of NOX1 to plasma membrane. Of note, PKCδ, when it was activated by PDPK1, directly bound to the SH3-N domain of p47<SUP>phox</SUP> and catalyzed the phosphorylation on Ser348 and Ser473 residues of p47<SUP>phox</SUP> C-terminal in a K-Ras-dependent manner, finally leading to its membrane translocation. Notably, oncogenic K-Ras activated all MAPKs (JNK, ERK and p38); however, only p38 was involved in p47<SUP>phox</SUP>-NOX1-dependent ROS generation and consequent transformation. Importantly, K-Ras-induced activation of p38 led to an activation of PDPK1, which then signals through PKCδ, p47<SUP>phox</SUP> and NOX1. In agreement with the mechanism, inhibition of p38, PDPK1, PKCδ, p47<SUP>phox</SUP> or NOX1 effectively blocked K-Ras-induced ROS generation, anchorage-independent colony formation and tumor formation. Taken together, our findings demonstrated that oncogenic K-Ras activates the signaling cascade p38/PDPK1/PKCδ/p47<SUP>phox</SUP>/NOX1 for ROS generation and consequent malignant cellular transformation.

Effects of catalpalactone on dopamine biosynthesis and L-DOPA-induced cytotoxicity in PC12 cells

Huang, H.S.,Han, X.H.,Hwang, B.Y.,Park, J.I.,Yoo, S.K.,Lee, H.J.,Lim, S.C.,Lee, M.K. Elsevier Science B.V 2008 Environmental toxicology and pharmacology Vol.26 No.1

The effects of catalpalactone on dopamine biosynthesis and L-DOPA-induced cytotoxicity in PC12 cells were investigated. Catalpalactone at 5-30μM decreased intracellular dopamine content with the IC<SUB>50</SUB> value of 22.1μM. Catalpalactone at 5-20μM, but not 30μM, did not alter cell viability. Catalpalactone at 20μM inhibited tyrosine hydroxylase (TH) and aromatic-l-amino acid decarboxylase (AADC) activities. Catalpalactone also decreased cyclic AMP levels and inhibited TH phosphorylation. In addition, catalpalactone at 20μM reduced the increases in dopamine levels induced by L-DOPA (20-50μM). Catalpalactone (5-30μM) associated with L-DOPA (50-100μM) enhanced L-DOPA-induced cytotoxicity at 48h, which was prevented by N-acetyl-l-cysteine. These results suggest that catalpalactone inhibited dopamine biosynthesis by reducing TH and AADC activities and enhanced L-DOPA-induced cytotoxiciy in PC12 cells.

Experimental study of flow boiling heat transfer and dryout characteristics at low mass flux in helically-coiled tubes

Hwang, K.W.,Kim, D.E.,Yang, K.H.,Kim, J.M.,Kim, M.H.,Park, H.S. North-Holland Pub. Co 2014 Nuclear engineering and design Vol.273 No.-

The goals of this study were to understand flow boiling phenomena in helically-coiled tubes and to predict their flow boiling heat transfer coefficients (HTC) and dryout qualities. Flow heat transfer and dryout were experimentally investigated in coiled tubes of 12-mm inside diameter and 17-mm outside diameter. The helical diameters D<SUB>h</SUB> of the coiled tubes used were 606mm and 977mm for the HTC experiments and 606mm, 977mm, and 1290mm for the dryout experiments. In flow boiling experiments mass flux G was 88.4-530.5kg/(m<SUP>2</SUP>s), system pressure P was 1-6MPa, and heat flux q'' to the tube wall was 30.0-1145.3kW/m<SUP>2</SUP>. For dryout experiments, q'' was 131.3-1764.9kW/m<SUP>2</SUP>. Flow boiling heat transfer in the coiled tubes was significantly affected by nucleate boiling and convective boiling, and not by secondary flow due to the helical coiling. HTC in the coiled tubes were accurately predicted (standard deviation 29%) by Steiner and Taborek HTC correlation for straight vertical tubes. Dryout qualities were significantly influenced by the coiled tubes. The effects of D<SUB>h</SUB>, G, and P were greatly affected by secondary flow caused by the coiled tubes. Dryout in the coiled tubes can be only predicted using dryout correlations for them. The dryout map proposed by Berthoud and Jayanti was modified to consider the effects of redeposition and gravity; this modified correlation accurately predicted dryout qualities (standard deviation 10.1%) within the range of experimental conditions. These results will help guide design of cooling systems that use helical coils.

분만년도, 계절 및 산차가 한우의 비유곡선에 미치는 영향

황정미,최재관,전기준,나기준,여인서,양부근,이채영,김종복 한국동물자원과학회 2002 한국축산학회지 Vol.44 No.6

축산기술연구소 대관령지소에서 사육된 한우 암소 118두에 대해 산유량 및 비유곡선을 추정하고자 하였다. 분만 후 1, 2, 3 및 4개월의 일일 평균 산유량은 3.74±0.96㎏, 3.64±0.97㎏, 3.26±1.15㎏ 및 2.99±1.08㎏ 이었으며 4개월간의 일일 평균 산유량은 3.52±0.84㎏이었다. 일반적인 비유곡선의 상수 추정치는 A(분만 직후 첫유량)가 2.4845, b(상향경사도)가 0.1734 및 c(하향경사도)가 0.0060이었다. 최고 추정유량은 3.75㎏이었고 최고 유량 도달시기는 29.03일이었는데 초산우 보다는 경산우가 최고 추정 유량이 높고 최고 유량 도달시기가 늦어지는 것으로 나타났으며 봄철 분만우가 가을철 분만우에 비해 최고 추정 유량이 높고 최고 유량 도달시기가 늦어지는 것으로 나타났으며 봄철 분만우가 가을철 분만우에 비해 최고 추정 유량이 높고 최고 유량 도달시기도 빨라지는 경향을 보였다. This study was conducted to investigate the effect of environmental factor on milk yield and to estimate lactation curve in Korean cattle. The data for milk yields were collected from 118 cows from 1997 to 2000 at National Livestock Research Institute in Daekwanryoung, Kangwon-do. Average daily milk yields for 1st, 2nd, 3rd and 4th month after calving were 3.74㎏, 3.64㎏, 3.26㎏ and 2.99㎏. Average daily milk yield for the four months was 3.52㎏. The milk yields for cows calved in spring were larger than those calved in fall. Lactation curve of Korean cattle was y_n=2.4845n^0.1734e^-0.0060n. Peak milk yield was 3.75㎏ on 29.03 day after calving. The peak milk yields for multi-parous cows were larger than those of primiparous cows. The peak milk yields for multi-parous cows reached later than those for primiparous cows. The cows calved in spring had higher and earlier peak milk yields than those calved in fall had.

OGLE‐2009‐BLG‐023/MOA‐2009‐BLG‐028: characterization of a binary microlensing event based on survey data

Hwang, K.‐,H.,Han, C.,Udalski, A.,Sumi, T.,Gould, A.,Jaroszyń,ski, M.,Kubiak, M.,Szymań,ski, M. K.,Pietrzyń,ski, G.,Soszyń,ski, I.,Szewczyk, O.,Ulaczyk, K.,Wyrzykowski,  Blackwell Publishing Ltd 2011 MONTHLY NOTICES- ROYAL ASTRONOMICAL SOCIETY Vol.413 No.2

<P><B>ABSTRACT</B></P><P>We report the result of the analysis of the light curve of a caustic‐crossing binary‐lens microlensing event OGLE‐2009‐BLG‐023/MOA‐2009‐BLG‐028. Even though the event was observed solely by survey experiments, we could uniquely determine the mass of the lens and distance to it by simultaneously measuring the Einstein radius and lens parallax. From this, we find that the lens system is composed of M‐type dwarfs with masses (0.50 ± 0.07) and (0.15 ± 0.02) M<SUB>⊙</SUB> located in the Galactic disc with a distance of ∼1.8 kpc toward the Galactic bulge direction. The event demonstrates that physical lens parameters of binary‐lens events can be routinely determined from future high‐cadence lensing surveys and thus microlensing can provide a new way to study Galactic binaries.</P>

SQUIDs in biomagnetism: a roadmap towards improved healthcare

Kö,rber, Rainer,Storm, Jan-Hendrik,Seton, Hugh,Mä,kelä,, Jyrki P,Paetau, Ritva,Parkkonen, Lauri,Pfeiffer, Christoph,Riaz, Bushra,Schneiderman, Justin F,Dong, Hui,Hwang, Seong-min,You, Lixi IOP 2016 Superconductor science & technology Vol.29 No.11

<P>Globally, the demand for improved health care delivery while managing escalating costs is a major challenge. Measuring the biomagnetic fields that emanate from the human brain already impacts the treatment of epilepsy, brain tumours and other brain disorders. This roadmap explores how superconducting technologies are poised to impact health care. Biomagnetism is the study of magnetic fields of biological origin. Biomagnetic fields are typically very weak, often in the femtotesla range, making their measurement challenging. The earliest <I>in vivo</I> human measurements were made with room-temperature coils. In 1963, Baule and McFee (1963 <I>Am</I>. <I>Heart J</I>. <A HREF='http://dx.doi.org/10.1016/0002-8703(63)90075-9'> <B>55</B> 95−6</A>) reported the magnetic field produced by electric currents in the heart (‘magnetocardiography’), and in 1968, Cohen (1968 <I>Science</I> <A HREF='http://dx.doi.org/10.1126/science.161.3843.784'> <B>161</B> 784−6</A>) described the magnetic field generated by alpha-rhythm currents in the brain (‘magnetoencephalography’). Subsequently, in 1970, Cohen <I>et al</I> (1970 <I>Appl. Phys. Lett.</I> <A HREF='http://dx.doi.org/10.1063/1.1653195'> <B>16</B> 278–80</A>) reported the recording of a magnetocardiogram using a Superconducting QUantum Interference Device (SQUID). Just two years later, in 1972, Cohen (1972 <I>Science</I> <A HREF='http://dx.doi.org/10.1126/science.175.4022.664'> <B>175</B> 664–6</A>) described the use of a SQUID in magnetoencephalography. These last two papers set the scene for applications of SQUIDs in biomagnetism, the subject of this roadmap.</P> <P>The SQUID is a combination of two fundamental properties of superconductors. The first is flux quantization—the fact that the magnetic flux Φ in a closed superconducting loop is quantized in units of the magnetic flux quantum, Φ<SUB>0</SUB> ≡ <I>h</I>/2<I>e</I>, ≈ 2.07 × 10<SUP>−15</SUP> Tm<SUP>2</SUP> (Deaver and Fairbank 1961 <I>Phys. Rev. Lett.</I> <A HREF='http://dx.doi.org/10.1103/PhysRevLett.7.43'> <B>7</B> 43–6</A>, Doll R and Näbauer M 1961 <I>Phys. Rev. Lett.</I> <A HREF='http://dx.doi.org/10.1103/PhysRevLett.7.51'> <B>7</B> 51–2</A>). Here, <I>h</I> is the Planck constant and <I>e</I> the elementary charge. The second property is the Josephson effect, predicted in 1962 by Josephson (1962 <I>Phys. Lett.</I> <A HREF='http://dx.doi.org/10.1016/0031-9163(62)91369-0'> <B>1</B> 251–3</A>) and observed by Anderson and Rowell (1963 <I>Phys. Rev. Lett.</I> <A HREF='http://dx.doi.org/10.1103/PhysRevLett.10.230'> <B>10</B> 230–2</A>) in 1963. The Josephson junction consists of two weakly coupled superconductors separated by a tunnel barrier or other weak link. A tiny electric current is able to flow between the superconductors as a supercurrent, without developing a voltage across them. At currents above the ‘critical current’ (maximum supercurrent), however, a voltage is developed. In 1964, Jaklevic <I>et al</I> (1964 <I>Phys. Rev. Lett.</I> <A HREF='http://dx.doi.org/10.1103/PhysRevLett.12.159'> <B>12</B> 159–60</A>) observed quantum interference between two Josephson junctions connected in series on a superconducting loop, giving birth to the dc SQUID. The essential property of the SQUID is that a steady increase in the magnetic flux threading the loop causes the critical current to oscillate with a period of one flux quantum. In today’s SQUIDs, using conventional semiconductor readout electronics, one can typically detect a change in Φ corresponding to 10<SUP>−6</SUP> Φ<SUB>0</SUB> in one second. Although early practical SQUIDs were usually made from bulk superconductors, for example, niobium or Pb-Sn solder blobs, today’s devices are invariably made from thin superconducting films patterned with photolithography or even electron lithography. An extensive descri

Machining of the KSTAR TF coil structure

K. H. Hong,C. H. Choi,D. H. Park,D. K. Hur,H. Sin,H. K. Park,H. T. Kim,J. H. Won,J. H. Lim,J. M. Chung,박주식,J. W. Sa,J. Y. Song,N. G. Kim,S. H. Hwang,Y. D. Chu,Y. G. Song 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.III

The KSTAR Toroidal Field (TF) magnet system consists of 16 TF structures. Each structure must be machined for precise assembly and reducing error field. Dimensions of the structure are a height of 4.5 m and a width of 3.2 m. The allowable tolerance of the structure is ±1 2 mm, and that of the bolt hole for Poloidal Field (PF) coil basement is ±0.5 mm. The final machining of the structure is also important for assembly of the interface structures such as toroidal ring, PF coil structures, and Central Solenoid (CS) structure. Before coil encasing, the inside surface of the structure is machined. Most of the outer surface of the structure, except for the surface of the intercoil structure (ICS), is machined after final welding. In particular, the side surface of an inboard leg, the connection plate of the ICS, the toroidal ring basement, the PF structure basements, shear key holes, and conical bolt holes are precisely machined. Fabrication and assembly tolerances are absorbed by the thickness of the electrical insulation, the spacer of the shear key, and the taper ring of the conical bolt. Six TF coil structures have been assembled and two structures are waiting for assembly. Another three structures are under final machining. A laser tracker is used for three dimensional survey and measurement of the structure.

Effect of citric acid on the acidification of artificial pepsin solution for metacercariae isolation from fish

Kim, M.K.,Pyo, K.H.,Hwang, Y.S.,Chun, H.S.,Park, K.H.,Ko, S.H.,Chai, J.Y.,Shin, E.H. Elsevier Scientific Pub. Co 2013 Veterinary parasitology Vol.198 No.1

Artificial digestive solution based on pepsin is essential for collecting metacercariae from fish. To promote the enzymatic reactivity of pepsin, the pH of the solution has to be adjusted to pH 1.0-2.0. Hydrochloride (HCl) is usually used for this purpose, but the use of HCl raises safety concerns. The aim of this work was to address the usefulness of citric acid as an alternative for HCl for the acidification of pepsin solution, and to examine its potential to damage metacercariae during in vitro digestion as compared with HCl. Changes in pH after adding 1-9% of citric acid (m/v) to pepsin solution were compared to a 1% HCl (v/v) addition. Digestion of fish muscle was evaluated by measuring released protein concentrations by spectrophotometry. In addition, survival rates of metacercariae in pepsin solution were determined at different citric acid concentrations and were compared that of with 1% HCl. The present study shows that addition of citric acid reduced the pH of pepsin solutions to the required level. Addition of more than 5% of citric acid resulted in the effective digestion of fish muscle over 3h in vitro, and 5% citric acid was less lethal to metacercariae than 1% HCl in pepsin solution. Pepsin solution containing 5% citric acid had digestive capacity superior to pepsin solution containing 1% HCl after 3h incubation with released protein concentrations of 12.0ng/ml for 5% citric acid and 9.6ng/ml for 1% HCl. Accordingly, the present study suggests that the addition of 5% citric acid to pepsin solution is a good alternative to 1% HCl in infection studies because citric acid is a stable at room temperature and has a good safety profile. In addition, we suggest that the use of citric acid enables the preparation of commercial digestive solutions for the detection of microorganisms in fish and other vertebrate muscle tissue.