• The Korean Journal of Nuclear Medicine
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• v.39 no.6
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• pp.481-488
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• 2005

Purpose: Functional imaging of dopamine transporter (DAT) defines integrity of the dopaminergic system, and DAT is the target site of drugs of abuse such as cocaine and methamphetamine. Functional imaging the DAT may be a sensitive and selective indicator of neurotoxic change by the drug. The aim of the present study is to evaluate the clinical implications of qualitative/quantitative analyses of dopamine transporter imaging in methamphetamine abusers. Materials and Methods: Six detoxified methamphetamine abusers (abuser group) and 4 volunteers (control group) were enrolled in this study. Brain MRI was performed in all of abuser group. Abuser group underwent psychiatric and depression assessment using brief psychiatric rating scale (BPRS) and Hamilton depression rating scale (HAMD), respectively. All of the subjects underwent I-123 IPT SPECT (IPT SPECT). IPT SPECT image was analysed with visual qualitative method and quantitative method using basal ganglia dopamine transporter (DAT) specific/non-specific binding ratio (SBR). Comparison of DAT SBR between abuser and control groups was performed. We also performed correlation tests between psychiatric and depression assessment results and DAT SBR in abuser group. Results: All of abuser group showed normal MRI finding, but had residual psychiatric and depressive symptoms, and psychiatric and depressive symptom scores were exactly correlated (r=1.0, p=0.005) each other. Five of them showed abnormal finding on qualitative visual I-123 IPT SPECT Abuser group had lower basal ganglia DAT SBR than that of control ($2.38{\pm}0.20\;vs\;3.04{\pm}0.27$, p=0.000). Psychiatric and depressive symptoms were negatively well correlated with basal ganglia DAT SBR (r=-0.908, p=0.012, r=-0.924, p=0.009). Conclusion: These results suggest that dopamine transporter imaging using I-123 IPT SPECT may be used to evaluate dopaminergic system of the basal ganglia and the clinical status in methamphetamine abusers.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.3
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• pp.241-246
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• 2007

Purpose: $[^{11}C]6-OH-BTA-1$ ([N-methyl-$^{11}C$]2-(4'-methylaminophenyl)-6-hydroxybenzothiazole, 1), a -amyloid imaging agent for the diagnosis of Alzheimer's disease in PET, can be labeled with higher yield by a simple loop method. During the synthesis of $[^{11}C]1$, we found the formation of by-products in various solvents, e.g., methylethylketone (MEK), cyclohexanone (CHO), diethylketone (DEK), and dimethylformamide (DMF). Materials and Methods: In Automated radiosynthesis module, 1 mg of 4-aminophenyl-6-hydroxybenzothiazole (4) in 100 l of each solvent was reacted with $[^{11}C]methyl$ triflate in HPLC loop at room temperature (RT). The reaction mixture was separated by semi-preparative HPLC. Aliquots eluted at 14.4, 16.3 and 17.6 min were collected and analyzed by analytical HPLC and LC/MS spectrometer. Results: The labeling efficiencies of $[^{11}C]1$ were $86.0{\pm}5.5%$, $59.7{\pm}2.4%$, $29.9{\pm}1.8%$, and $7.6{\pm}0.5%$ in MEK, CHO, DEK and DMF, respectively. The LC/MS spectra of three products eluted at 14.4, 16.3 and 17.6 mins showed m/z peaks at 257.3 (M+1), 257.3 (M+1) and 271.3 (M+1), respectively, indicating their structures as 1, 2-(4'-aminophenyl)-6-methoxybenzothiazole (2) and by-product (3), respectively. Ratios of labeling efficiencies for the three products $([^{11}C]1:[^{11}C]2:[^{11}C]3)$ were $86.0{\pm}5.5%:5.0{\pm}3.4%:1.5{\pm}1.3%$ in MEK, $59.7{\pm}2.4%:4.7{\pm}3.2%:1.3{\pm}0.5%$ in CHO, $9.9{\pm}1.8%:2.0{\pm}0.7%:0.3{\pm}0.1%$ in DEK and $7.6{\pm}0.5%:0.0%:0.0%$ in DMF, respectively. Conclusion: The labeling efficiency of $[^{11}C]1$ was the highest when MEK was used as a reaction solvent. As results of mass spectrometry, 1 and 2 were conformed. 3 was presumed.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.3
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• pp.234-240
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• 2007

Purpose: In this study we propose a block-iterative method for reconstructing Compton scattered data. This study shows that the well-known expectation maximization (EM) approach along with its accelerated version based on the ordered subsets principle can be applied to the problem of image reconstruction for Compton camera. This study also compares several methods of constructing subsets for optimal performance of our algorithms. Materials and Methods: Three reconstruction algorithms were implemented; simple backprojection (SBP), EM, and ordered subset EM (OSEM). For OSEM, the projection data were grouped into subsets in a predefined order. Three different schemes for choosing nonoverlapping subsets were considered; scatter angle-based subsets, detector position-based subsets, and both scatter angle- and detector position-based subsets. EM and OSEM with 16 subsets were performed with 64 and 4 iterations, respectively. The performance of each algorithm was evaluated in terms of computation time and normalized mean-squared error. Results: Both EM and OSEM clearly outperformed SBP in all aspects of accuracy. The OSEM with 16 subsets and 4 iterations, which is equivalent to the standard EM with 64 iterations, was approximately 14 times faster in computation time than the standard EM. In OSEM, all of the three schemes for choosing subsets yielded similar results in computation time as well as normalized mean-squared error. Conclusion: Our results show that the OSEM algorithm, which have proven useful in emission tomography, can also be applied to the problem of image reconstruction for Compton camera. With properly chosen subset construction methods and moderate numbers of subsets, our OSEM algorithm significantly improves the computational efficiency while keeping the original quality of the standard EM reconstruction. The OSEM algorithm with scatter angle- and detector position-based subsets is most available.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.3
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• pp.192-200
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• 2008

To evaluate the hemodynamic changes and the predictive factors of the clinical outcome in pediatric patients with moyamoya disease, we analyzed pre/post basal/acetazolamide stress brain perfusion SPECT with automated volume of interest (VOIs) method. Methods: Total fifty six (M:F = 33:24, age $6.7{\pm}3.2$ years) pediatric patients with moyamoya disease, who underwent basal/acetazolamide stress brain perfusion SPECT within 6 before and after revascularization surgery (encephalo-duro-arterio-synangiosis (EDAS) with frontal encephalo-galeo-synangiosis (EGS) and EDAS only followed on contralateral hemisphere), and followed-up more than 6 months after post-operative SPECT, were included. A mean follow-up period after post-operative SPECT was $33{\pm}21$ months. Each patient's SPECT image was spatially normalized to Korean template with the SPM2. For the regional count normalization, the count of pons was used as a reference region. The basal/acetazolamide-stressed cerebral blood flow (CBF), the cerebral vascular reserve index (CVRI), and the extent of area with significantly decreased basal/acetazolamide- stressed rCBF than age-matched normal control were evaluated on both medial frontal, frontal, parietal, occipital lobes, and whole brain in each patient's images. The post-operative clinical outcome was assigned as good, poor according to the presence of transient ischemic attacks and/or fixed neurological deficits by pediatric neurosurgeon. Results: In a paired t-test, basal/acetazolamide-stressed rCBF and the CVRI were significantly improved after revascularization (p<0.05). The significant difference in the pre-operative basal/acetazolamide-stressed rCBF and the CVRI between the hemispheres where EDAS with frontal EGS was performed and their contralateral counterparts where EDAS only was done disappeared after operation (p<0.05). In an independent student t-test, the pre-operative basal rCBF in the medial frontal gyrus, the post-operative CVRI in the frontal lobe and the parietal lobe of the hemispheres with EDAS and frontal EGS, the post-operative CVRI, and ${\Delta}CVRI$ showed a significant difference between patients with a good and poor clinical outcome (p<0.05). In a multivariate logistic regression analysis, the ${\Delta}CVRI$ and the post-operative CVRI of medial frontal gyrus on the hemispheres where EDAS with frontal EGS was performed were the significant predictive factors for the clinical outcome (p =0.002, p =0.015), Conclusion: With probabilistic map, we could objectively evaluate pre/post-operative hemodynamic changes of pediatric patients with moyamoya disease. Specifically the post-operative CVRI and the post-operative CVRI of medial frontal gyrus where EDAS with frontal EGS was done were the significant predictive factors for further clinical outcomes.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.3
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• pp.235-245
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• 2008

Purpose: The HSV1-tk gene has been extensively studied as a type of reporter gene. In hepatocellular carcinoma (HCC), only a small proportion of patients are eligible for surgical resection and there is limitation in palliative options. Therefore, there is a need for the development of new treatment modalities and gene therapy is a leading candidate. In the present study, we investigated the usefulness of substrate, 2'-fluoro-2'-deoxy-1-${\beta}$-D-arabino-furanosyi-5-[$^{124/125}I$]iodo- uracil ([$I^{124/125}I$]FIAU) as a non-invasive imaging agent for HSV1-tk gene therapy in hepatoma model using small animal PET. Material and Methods: With the Morris hepatoma MCA cell line and MCA-tk cell line which was transduced with the HSV1-tk gene, in vitro uptake and correlation study between [$^{125}I$]FIAU uptake according to increasing numeric count of percentage of MCA-tk cell were performed. The biodistribution data and small animal PET images with [$^{124}I$]FIAU were obtained with Balb/c-nude mice bearing both MCA and MCA-tk tumors. Results:, Specific accumulation of [[$^{125}I$]FIAU was observed in MCA-tk cells but uptake was low in MCA cells. Uptake in MCA-tk cells was 15 times higher than that of MCA cells at 480 min. [$^{125}I$]FIAU uptake was linearly correlated (R2 =0.964, p =0.01) with increasing percentage of MCA-tk numeric cell count. Biodistribution results showed that [$^{125}I$]FIAU was mainly excreted via the renal system in the early phase. Ratios of MCA-tk tumor to blood acting were 10, 41, and 641 at 1 h, 4 h, and 24 h post-injection, respectively. The maximum ratio of MCA-tk to MCA tumor was 192.7 at 24 h. Ratios of MCA-tk tumor to liver were 13.8, 66.8, and 588.3 at 1 h, 4 h, and 24 h, respectively. On small animal PET, [$^{124}I$]FIAU accumulated in substantial higher levels in MCA-tk tumor and liver than MCA tumor. Conclusion: FIAU shows selective accumulation to HSV1-tk expressing hepatoma cell tumors with minimal uptake in normal liver. Therefore, radiolabelled FIAU is expected to be a useful substrate for non-invasive imaging of HSV1-tk gene therapy and therapeutic response monitoring of HCC.

• Korean Journal of Environmental Agriculture
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• v.18 no.2
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• pp.126-134
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• 1999

To provide the basic information for the water improvement and control of water resource in Nakdong river districts, the physico-chemical characteristics of water in four main streams and three branch streams of the river were investigated through 36 times totally, one time per each month from January in 1995 to November in 1997. The pH values of each sites in main or branch stream of Nakdong river was pH $6.3{\sim}9.3$ range, pH range of Jukpo and Namji area at spring and fall was almost over pH 8.5, which was exceeded the water quality standard for agriculture. DO values of Nakdong river was almost $8.0{\sim}13mg/l$, except for Kangchang area in downstream of Kumho river. BOD values in Dasa area where was prior to mixing of Kumho river was $1.5{\sim}4.8mg/l$, which was under the water quality standard for agriculture(8mg/l), but BOD values followed mixing of Kumho river was over the permit standard of agricultural water as $3.8{\sim}8.9mg/l$ in Koryung, $3.4{\sim}8.4mg/l$ in Jukpo and $3.3{\sim}7.8mg/l$ in Namji according to time or season. Especially, BOD values at Gangchang area in Kumho river were $7.6{\sim}18.5mg/l$, which was over the water quality standard for agriculture and so Kumho river was a main pollutant: source of Nakdong river. COD values of main stream of Nakdong river was over the permit standard of agriculture(8mg/l) as $5.2{\sim}13.5mg/l$ in Koryvng, $5.0{\sim}12.7mg/l$ in Jukpo and $5.0{\sim}12.2mg/l$ in Namji according to time or season. And COD values was much high rather than BOD values and its gap of concentration was increased along with downstream. $NH_4-N$ of main stream of Nakdong river followed mixing of Kumho river($0.5{\sim}13.1mg/l$) was the highest affected in Koryung($0.18{\sim}5.0mg/l$) and detected much more in winter than in summer. T-N in Koryung($4.96{\sim}12.06mg/l$) followed mixing of Kumho river was significantly high rather than $2.86{\sim}4.86mg/l$ in Dasa, $4.20{\sim}8.20mg/l$ in Jukpo and $3.18{\sim}8.64mg/l$ in Namji, which was almost over the permit standard of agricultural water(1.0mg/l). T-P in Koryung($0.10{\sim}0.58mg/l$) also was significantly high rather than those $0.07{\sim}0.36mg/l$ in Jukpo and $0.08{\sim}0.4mg/l$ in Namji as over the standard of agricultural water(0.1mg/l). The concentration of T-N or T-P in Nakdong districts was trended of increasing in every year.

• Applied Microscopy
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• v.30 no.2
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• pp.213-232
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• 2000

The development of the knee joint was studied by electron microscopy in human fetuses ranging from 20 mm to 260 mm crown-rump length ($7\sim30$ weeks of gestational age). The appearance of the primordium of the meniscus and cruciate ligament was conspicuous as the mesenchymal cells , preceeding that of joint space at 30 mm fetus. The primitive joint cavity was first seen in the interzone from the 40 mm fetus and its intermediate layer proceeded developing as a narrow cleft which was closely incorporated with two chondrogenic layers. Poorly differentiated mesenchymal cells of the meniscus at 40 mm fetus containing predominantly free ribosomes differentiated into fibroblasts at 60 mm fetus. By 100 mm fetus, the fibroblast in inner zone of the meniscus presented as oval profiles with a short cell processes, whereas middle and peripheral zones presented as elongated cells. Differentiation of the synovial membrane coincided with clarification of the joint cavity When dilatation of the synovial cavity occurred, the two types of synovial cells were identified at 60 mm fetus. By 100 mm fetus a majority of the intimal cells were B-type. B-type cells were clearly distinguishable from A-type cells by their content of extensive rough endoplasmic reticula and well developed Golgi complexes. In contrast, A-type cells had numerous filopodia, pinocytotic vesicles, lysosomes and large vacuoles. At 260 mm fetus the B-type cells were also a majority of intimal cells. At 260 mm fetus the inner zone of the meniscus was filled with parallel oriented fascicles of collagenous fibers and oval fibroblasts. The middle zone was constituted of parallel and radially arranged fibers and fibroblasts. The outer zone was populated by elongated fibroblasts encircled by crossed collagenous fibers with the blood vessels. At 30 mm fetus the fibroblasts of the cruciate ligament contained rough endoplasmic reticula and mitochondria. Collagen fibrils were noted within narrow cytoplasmic processes which were continued with the extracellular space. Collagen fibrils of ligament were filled in the bulk of extracellular space at 100 mm fetus. By $150\sim260mm$ fetus, the cruciate ligaments were constituted of longitudinally oriented bundle of collagen fibrils with irregular rows of round cells between.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.3
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• pp.199-213
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• 2020

Grain size and shape are the two important components contributing to rice yield and quality. To analyze traits related to grain-shape, a total of 272 varieties derived from japonica, japonica black and Tongil-type rice accession in Korea were evaluated in this study. The traits, grain length (GL), grain width (GW), grain thickness (GT), length to width ratio (RLW), and 1000-grain weight (TGW) were measured and replicated 10 times. Genes (GW2, GS3, qGL3, qSW5, GS5, TGW6, GW7, and GW8) related to grain-shape were validated in the accessions using specific DNA marker sets. K-mean clustering of the accession based on phenotypic data revealed three groups: group 1 was classified by GW and GT and included most of japonica type, group 2 was classified by RLW and GL reached a medium size and possessed a half spindle-shaped type, and group 3 was classified by TGW, reached a long size and possessed a semi-round shape. In validation tests using the marker sets, both gw2 and tgw6 were validated in less than 1% of the tested accessions and two allelic types, qgl3 and gw8, were only verified in Tongil-type accessions. For GW8 and GW2, any different amplicons were not amplified in any japonica or Tongil-type accessions, respectively. In order to suggest the representative grain-shape gene combinations for each ecotype, the allelic combinations were evaluated by PCR analysis. Cj1 and 2 in japonica (Cj1-7), Cj_b1 and 2 in japonica-black (Cj_b1-3), and CT3 in Tongil-type (CT1-13) turned out to be the dominant combination in each ecotype, respectively. In addition, the results revealed that introgression of four genes (gw2, gs3, qSW5, and GS5) would expand the diversity of grain shape in Korean japonica varieties. The gene combinations information could be utilized practically to understand or enhance grain shape in japonica rice breeding program.

• Economic and Environmental Geology
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• v.8 no.1
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• pp.1-23
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• 1975

The subject of this study deals with phase relations between stannite ($Cu_2FeSnS_4$) and sphalerite (${\beta}-ZnS$)/wurtzite (${\alpha}-ZnS$). The phase relations were systematically investigated from liquidus temperature to $400^{\circ}C$ under controlled conditions. ${\beta}-stannite$ (tetragonal) is stable up to $706{\pm}5^{\circ}C$, where it inverts to a high-temperature polymorph ${\alpha}-stannite$ (cubic) melting congruently at $867{\pm}5^{\circ}C$. Sphalerite (cubic, ${\beta}-ZnS$) inverts at $1013{\pm}3^{\circ}C$ to wurtzite, which is the hexagonal hightemperature polymorph of ZnS. Between ${\alpha}-stannite$ and sphalerite a complete solid solution series exists above approximately $870^{\circ}C$ up to solidus temperature. The melting temperature of ${\alpha}-stannite$ rises towards sphalerite and reaches a maximum at $1074{\pm}3^{\circ}C$, which is the peritectic with the composition of 91 wt. % sphalerite and 9 wt. % ${\alpha}-stannite$. At this temperature, wurtzite takes only 5wt. % ${\alpha}-stannite$ in solid solution which decreases with increasing temperature. The inverson temperature of ${\alpha}/{\beta}-stannite$ is lowered with increasing amounts of sphalerite in solid solution down to $614{\pm}7^{\circ}C$, which is the eutectoid with the composition of 13 wt. % sphalerite and 87 wt. % ${\alpha}-stannite$. Here, ${\beta}-stannite$ contains only 10wt. % sphalerite in solid solution. With decreasing temperature, the ranges of the solid solution on both sides of the system narrow. The phase relations in the above pure system changed due to the FeS impurities in the sphalerite solid solution. The eutectoid increased from $614{\pm}7^{\circ}C$ up to $695{\pm}5^{\circ}C$ (5 wt. % FeS) and $700{\pm}5^{\circ}C$ (10wt. % FeS), while the peritectic decreased from $1074{\pm}3^{\circ}C$ down to $1036{\pm}3^{\circ}C$ (wt. %FeS) and $987{\pm}3^{\circ}C$ (10wt. %FeS). A most notable change is the appearance of non-binary regions. An important feature is the combination of this study system with the experimental results reported by Sprinfer (1972). If a stannite-kesterite solid solution is used in the place of stannite as a bulk composition, the inversion temperature is lowered to less than $400^{\circ}C$ which belongs to temperatures of the hydrothermal region.

• Economic and Environmental Geology
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• v.40 no.6
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• pp.713-726
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• 2007

The Daebong deposit consists of gold-silver-bearing mesothermal massive quartz veins which fill fractures along fault zones($N10{\sim}20^{\circ}W,\;40{\sim}60^{\circ}SW$) within banded gneiss or granitic gneiss of Precambrian Gyeonggi massif. Ore mineralization of the deposit is composed of massive white quartz vein(stage I) which was formed in the same stage by multiple episodes of fracturing and healing and transparent quartz vein(stage II) which is separated by a major faulting event. The hydrothermal alteration of stage I is sericitization, chloritization, carbonitization, pyritization, silicification and argillization. Sericitic zone occurs near and at quartz vein and includes mainly sericite, quartz, and minor illite, carbonates and epidote. Chloritic zone occurs far from quartz vein and is composed of mainly chlorite, quartz and minor sericite, carbonates and epidote. Fe/(Fe+Mg) ratios of sericite and chlorite range 0.36 to 0.59($0.51{\pm}0.10$) and 0.66 to 0.73($0.70{\pm}0.02$), and belong to muscovite-petzite series and brunsvigite, respectively. Calculated $Al_{IV}-Fe/(Fe+Mg)$ diagrams of sericite and chlorite suggest that this can be a reliable indicator of alteration temperature in Au-Ag deposits. Calculated activities of chlorite end member are $a3(Fe_5Al_2Si_3O_{10}(OH){_6}=0.00964{\sim}0.0291,\;a2(Mg_5Al_2Si_3O_{10}(OH){_6}= 9.99E-07{\sim}1.87E-05,\;a1(Mg_6Si_4O_{10}(OH){_6}=5.61E-07{\sim}1.79E-05$. It suggest that chlorite from the Daebong deposit is iron-rich chlorite formed due to decreasing temperature from $T>450^{\circ}C$. Calculated $log\;{\alpha}K^+/{\alpha}H^+,\;log\;{\alpha}Na^+/{\alpha}H^+,\;log\;{\alpha}Ca^{2+}/{\alpha}^2H^+$ and pH values during wall-rock alteration are $4.6(400^{\circ}C),\;4.1(350^{\circ}C),\;4.0(400^{\circ}C),\;4.2(350^{\circ}C),\;1.8(400^{\circ}C),\;4.5(350^{\circ}C),\;5.4{\sim}6.5(400^{\circ}C)\;and\;5.1{\sim}5.5(350^{\circ}C)$, respectively. Gain elements (enrichment elements) during wallrock alteration are $K_2O,\;P_2O_5,\;Na2O$, Ba, Sr, Cr, Sc, V, Pb, Zn, Be, Ag, As, Ta and Sb. Elements(Sr, V, Pb, Zn, As, Sb) represent a potentially tools for exploration in mesothermal and epithermal gold-silver deposits.