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Ko M, Jang T, Yoon S, Lee J, Choi JH, Choi JW, Park JA. Synthesis of recyclable and light-weight graphene oxide/chitosan/genipin sponges for the adsorption of diclofenac, triclosan, and microplastics. Chemosphere 2024; 356:141956. [PMID: 38604514 DOI: 10.1016/j.chemosphere.2024.141956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 03/16/2024] [Accepted: 04/07/2024] [Indexed: 04/13/2024]
Abstract
Emerging micropollutants, such as pharmaceuticals and microplastics (MPs), have become a pressing water environmental concern. The aim of this study is to synthesize chitosan sponges using graphene oxide (GO) and genipin (GP) for the removal of pharmaceuticals (diclofenac (DCF) and triclosan (TCS)) and MPs, verify their adsorption mechanisms, evaluate the effects of temperature, pH, and salinity on their adsorption capacities, and determine their reusability. The GO5/CS/GP sponge exhibited a macroporous nature (porosity = 95%, density = 32.6 mg/cm3). GO and cross-linker GP enhanced the adsorption of DCF, TCS, and polystyrene (PS) MPs onto the CS sponges. The adsorption of DCF, TCS, and PS MPs involved multiple steps: surface diffusion and pore diffusion of the sponge. The adsorption isotherms demonstrated that Langmuir model was the most fitted well model to explain adsorption of TCS (qm = 7.08 mg/g) and PS MPs (qm = 7.42 mg/g) on GO5/CS/GP sponge, while Freundlich model suited for DCF adsorption (qm = 48.58 mg/g). DCF adsorption was thermodynamically spontaneous and endothermic; however, the adsorption of TCS and PS MPs was exothermic (283-313 K). The optimal pH was 5.5-7 due to the surface charge of the GO5/CS/GP sponge (pHzpc = 5.76) and ionization of DCF, TCS, and PS MPs. As the salinity increased, DCF removal efficiency drastically decreased due to the weakening of electrostatic interactions; however, TCS removal efficiency remained stable because TCS adsorption was mainly caused by hydrophobic and π-π interactions rather than electrostatic interaction. The removal of PS MPs was enhanced by the electrostatic screening effects of high Na+ ions. PS nanoplastics (average size = 26 nm) were removed by the GO5/CS/GP sponge at a rate of 73.0%, which was better than that of PS MPs (41.5%). In addition, the GO5/CS/GP sponge could be recycled over five adsorption-desorption cycles.
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Affiliation(s)
- Mingi Ko
- Department of Environmental Engineering, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Taesoon Jang
- Department of Environmental Engineering, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Soyeong Yoon
- Department of Environmental Engineering, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Jooyoung Lee
- Department of Environmental Engineering, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Jin-Hyuk Choi
- Department of Integrated Energy and Infra System, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Jae-Woo Choi
- Water Cycle Research Center, Korea Institute of Science and Technology, Seoul, 02792, Republic of Korea; Division of Energy & Environment Technology, KIST School, Korea University of Science and Technology, Seoul, 02792, Republic of Korea
| | - Jeong-Ann Park
- Department of Environmental Engineering, Kangwon National University, Chuncheon 24341, Republic of Korea; Department of Integrated Energy and Infra System, Kangwon National University, Chuncheon 24341, Republic of Korea.
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Lee J, Jo SJ, Yoon S, Ko M, Jang T, Kim HK, Park JA. Coupled adsorption-photocatalysis process for the removal of diclofenac using magnetite/reduced graphene oxide nanocomposite. Chemosphere 2024; 349:140788. [PMID: 38042428 DOI: 10.1016/j.chemosphere.2023.140788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 10/28/2023] [Accepted: 11/21/2023] [Indexed: 12/04/2023]
Abstract
Diclofenac (DCF) is frequently detected in water bodies (ng/L to g/L) as it is not completely removed by conventional wastewater treatment plants. Adsorption and photocatalysis have been studied as promising methods for treating DCF; however, both processes have limitations. Thus, in this study, the removal efficiency of DCF is evaluated using a magnetite/reduced graphene oxide (Fe3O4/RGO) nanocomposite via a coupled adsorption-catalysis process. The Fe3O4/RGO nanocomposite was successfully synthesized using a microwave-assisted solvothermal method and exhibited a bandgap of 2.60 eV. The kinetic data best fitted the Elovich model (R2 = 0.994, χ2 = 0.29), indicating rapid adsorption. The maximum DCF adsorption capacity calculated using the Langmuir model was 80.33 mg/g. An ultraviolet C (UVC) light source and 0.1 g/L of Fe3O4/RGO nanocomposite were the optimum conditions for the removal of DCF (C0 = 30 mM) by a coupled adsorption-photocatalysis process (first-order rate constant (k) = 0.088/min), which was greater than the single adsorption (k = 0.029/min) and pre-adsorption and post-photocatalysis (k = 0.053/min) processes. This indicates that the adsorbed DCF did not hamper the photocatalytic reaction of the Fe3O4/RGO nanocomposite, but rather enhanced the coupled adsorption-photocatalytic reaction. DCF removal efficiency was higher at acidic conditions (pH 4.3-5.0), because high H+ promotes the generation of certain reactive oxygen species (ROS) and increases of electrostatic interaction. The presence of NaCl and CaCl2 (10 mM) did not notably affect the total DCF removal efficiency; however, Ca2+ affected the initial DCF adsorption affinity. Scavenger experiments demonstrated O2∙- and h+ play a key ROS than ·OH to degrade DCF. The acute toxicity of DCF towards Aliivibrio fischeri gradually decreased with increasing treatment time.
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Affiliation(s)
- Jooyoung Lee
- Department of Environmental Engineering, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Seong-Jun Jo
- Department of Battery Convergence Engineering, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Soyeong Yoon
- Department of Environmental Engineering, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Mingi Ko
- Department of Environmental Engineering, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Taesoon Jang
- Department of Environmental Engineering, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Hyun-Kyung Kim
- Department of Battery Convergence Engineering, Kangwon National University, Chuncheon, 24341, Republic of Korea; Interdisciplinary Program in Advanced Functional Materials and Devices Development, Kangwon National University, Chuncheon, 24341, Republic of Korea.
| | - Jeong-Ann Park
- Department of Environmental Engineering, Kangwon National University, Chuncheon, 24341, Republic of Korea; Department of Integrated Energy and Infra System, Kangwon National University, Chuncheon, 24341, Republic of Korea.
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Jang T, Hong E, Kim JH, Ha SJ, Choi JW, Park JA. Water quality seasonal variation assessment of the Gongji and Yaksa streams, Chuncheon, South Korea. Environ Monit Assess 2023; 195:1465. [PMID: 37957404 DOI: 10.1007/s10661-023-12069-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 10/28/2023] [Indexed: 11/15/2023]
Abstract
Gongji Stream flows into Lake Uiam, a potable water source for the capital region of Chuncheon, South Korea. Algal blooms often occur downstream of the Gongji stream in combination with drastic flow rate variations. Downstream water quality may also be affected by Yaksa stream. Yaksa stream joins Gongji stream before it reaches Uiam Lake, which is a drinking water source for the city. Limited data exists on the Yaksa stream water quality. Therefore, water quality parameters (pH, electrical conductivity (EC), biological oxygen demand (BOD), total nitrogen (T-N), total phosphorous (T-P), chlorophyll-a (Chl-a), total coliforms, and Escherichia coli (E. coli) concentration) were sampled from Gongji (at sites GJ1 and GJ2) and Yaksa (at sites YS1 and YS2) streams from May to September, 2022. The results revealed the overall water quality of both streams was good (BOD = 0.27-3.66 mg/L; TP = 0.003-0.074 mg/L), except on August 3. On August 3, the concentrations of BOD, TP, total coliforms, and E. coli were elevated, with the highest concentrations in samples from GJ2. The recent heavy rainfall potentially caused sewage inflows near GJ2. The correlation analysis revealed positive linear relationships in the 1-day cumulative precipitation with BOD (r = 0.503), total coliforms (r = 0.547), and TP (r = 0.814). The Yaksa stream may be an Anabaena sp. source, which contaminated samples from YS1, YS2, and GJ2, but not at GJ1 (upstream of the tributary).
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Affiliation(s)
- Taesoon Jang
- Department of Environmental Engineering, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Eunmi Hong
- School of Natural Resources and Environmental Science, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Jae-Hyun Kim
- Department of Earth and Environmental Sciences, Korea University, 145, Anam-Ro, Seongbuk-Gu, Seoul, 02841, Republic of Korea
| | - Suk-Jin Ha
- Department of Bioengineering, Division of Chemical Engineering and Bioengineering, College of Art, Culture and Engineering, Kangwon National University, Chuncheon, 24341, Republic of Korea
- Department of Smart Health Science and Technology, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Jae-Woo Choi
- Water Cycle Research Center, Korea Institute of Science and Technology, Seoul, 02792, Republic of Korea
- Division of Energy & Environment Technology, KIST School, Korea University of Science and Technology, Seoul, 02792, Republic of Korea
| | - Jeong-Ann Park
- Department of Environmental Engineering, Kangwon National University, Chuncheon, 24341, Republic of Korea.
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Yoon S, Lee J, Ko M, Jang T, Lim KS, Kim HO, Ha SJ, Park JA. Adsorption behavior of triclosan on microplastics and their combined acute toxicity to D. magna. Sci Total Environ 2023; 880:163290. [PMID: 37030274 DOI: 10.1016/j.scitotenv.2023.163290] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/31/2023] [Accepted: 03/31/2023] [Indexed: 05/27/2023]
Abstract
Microplastics (MP) have been recently identified as emerging water contaminants in worldwide. Owing to its physicochemical properties, MP have been considered as a vector of other micropollutants and may affect their fate and ecological toxicity in the water environment. In this study, triclosan (TCS), which is a widely-used bactericide, and three frequently found types of MP (PS-MP, PE-MP, and PP-MP) were investigated. The adsorption behavior of TCS on MP was investigated by the effect of reaction time, initial concentration of TCS, and other water chemistry factors. Elovich model and Temkin model are the most fitted well with kinetics and adsorption isotherms, respectively. The maximum TCS adsorption capacities were calculated for PS-MP (9.36 mg/g), PP-MP (8.23 mg/g), and PE-MP (6.47 mg/g). PS-MP had higher affinity to TCS owing to hydrophobic and π-π interaction. The TCS adsorption on PS-MP was inhibited by decreasing concentrations of cations, and increasing concentration of anion, pH, and NOM concentration. At pH 10, only 0.22 mg/g of adsorption capacity was obtained because of the isoelectric point (3.75) of PS-MP and pKa (7.9) of TCS. And almost no TCS adsorption occurred at NOM concentration of 11.8 mg/L. Only PS-MP had no acute toxic effect on D. magna, whereas TCS showed acute toxicity (EC50,24h of TCS = 0.36 ± 0.4 mg/L). Although survival rate increased when TCS with PS-MP due to lower the TCS concentration in solution via adsorption, PS-MP was observed in intestine and body surface of D. magna. Our findings can contribute to understanding the combined potential effects of MP fragment and TCS to aquatic biota.
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Affiliation(s)
- Soyeong Yoon
- Department of Environmental Engineering, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Jooyoung Lee
- Department of Environmental Engineering, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Mingi Ko
- Department of Environmental Engineering, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Taesoon Jang
- Department of Environmental Engineering, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Kwang Suk Lim
- Department of Bioengineering, Division of Chemical Engineering and Bioengineering, College of Art, Culture and Engineering, Kangwon National University, Chuncheon 24341, Republic of Korea; Department of Smart Health Science and Technology, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Hyun-Ouk Kim
- Department of Bioengineering, Division of Chemical Engineering and Bioengineering, College of Art, Culture and Engineering, Kangwon National University, Chuncheon 24341, Republic of Korea; Department of Smart Health Science and Technology, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Suk-Jin Ha
- Department of Bioengineering, Division of Chemical Engineering and Bioengineering, College of Art, Culture and Engineering, Kangwon National University, Chuncheon 24341, Republic of Korea; Department of Smart Health Science and Technology, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Jeong-Ann Park
- Department of Environmental Engineering, Kangwon National University, Chuncheon 24341, Republic of Korea.
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Baek N, Park Y, Lim H, Cha J, Jang T, Kang S, Jang S, Jung D. Change in Electrical/Mechanical Properties of Plasma Polymerized Low Dielectric Constant Films after Etching in CF 4/O 2 Plasma for Semiconductor Multilevel Interconnects. Materials (Basel) 2023; 16:4663. [PMID: 37444981 DOI: 10.3390/ma16134663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 06/13/2023] [Accepted: 06/20/2023] [Indexed: 07/15/2023]
Abstract
As semiconductor chips have been integrated to enhance their performance, a low-dielectric-constant material, SiCOH, with a relative dielectric constant k ≤ 3.5 has been widely used as an intermetal dielectric (IMD) material in multilevel interconnects to reduce the resistance-capacitance delay. Plasma-polymerized tetrakis(trimethylsilyoxy)silane (ppTTMSS) films were created using capacitively coupled plasma-enhanced chemical vapor deposition with deposition plasma powers ranging from 20 to 60 W and then etched in CF4/O2 plasma using reactive ion etching. No significant changes were observed in the Fourier-transform infrared spectroscopy (FTIR) spectra of the ppTTMSS films after etching. The refractive index and dielectric constant were also maintained. As the deposition plasma power increased, the hardness and elastic modulus increased with increasing ppTTMSS film density. The X-ray photoelectron spectroscopy (XPS) spectra analysis showed that the oxygen concentration increased but the carbon concentration decreased after etching owing to the reaction between the plasma and film surface. With an increase in the deposition plasma power, the hardness and elastic modulus increased from 1.06 to 8.56 GPa and from 6.16 to 52.45 GPa. This result satisfies the hardness and elastic modulus exceeding 0.7 and 5.0 GPa, which are required for the chemical-mechanical polishing process in semiconductor multilevel interconnects. Furthermore, all leakage-current densities of the as-deposited and etched ppTTMSS films were measured below 10-6 A/cm2 at 1 MV/cm, which is generally acceptable for IMD materials.
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Affiliation(s)
- Namwuk Baek
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Yoonsoo Park
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hyuna Lim
- Foundry Metal Technology Team, Samsung Electronics, 190 Seoku-dong, Hwaseong-si 18448, Republic of Korea
| | - Jihwan Cha
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Taesoon Jang
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Shinwon Kang
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Seonhee Jang
- Department of Mechanical Engineering, University of Louisiana at Lafayette, Lafayette, LA 70503, USA
| | - Donggeun Jung
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
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Lee S, Lee J, Choi CM, Oh IJ, Lee K, Jang T, Lee S, Kim E, Park D, Park S. 968TiP A phase II, multicenter study of lazertinib as consolidation therapy in patients with locally advanced, unresectable, EGFR mutation positive non-small cell lung cancer (stage III) who have not progressed following definitive, platinum-based, chemoradiation therapy (PLATINUM trial). Ann Oncol 2022. [DOI: 10.1016/j.annonc.2022.07.1094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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Jang T. P75.13 Hyperprogressive Disease in Non-Small Cell Lung Cancer on pd-1 Inhibitor. J Thorac Oncol 2021. [DOI: 10.1016/j.jtho.2021.01.1047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Jang T, Kim J. P1.04-18 PD-L1 Expression and its Correlation with Tumor TNM Stage in Patients with Non-Small Cell Lung Cancer. J Thorac Oncol 2018. [DOI: 10.1016/j.jtho.2018.08.733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Jang T, Lim J, Choo K, Nason S, Lee J, Oh S, Jeong S, Chestek C, Sylvester D, Blaauw D. A 2.2 NEF Neural-Recording Amplifier Using Discrete-Time Parametric Amplification. Symp VLSI Circuits 2018; 2018:237-238. [PMID: 35284197 PMCID: PMC8910781 DOI: 10.1109/vlsic.2018.8502432] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This paper proposes a 2.2 noise efficiency factor (NEF) instrumentation amplifier for neural recording applications. A parametric amplifier based on the MOS C-V characteristic is designed as a pre-amplifier stage, lowering the input referred noise of the following stages by 3.4×. Sampling noise is minimized by oversampling the input signal and switching power is reduced by adopting an 8-phase soft-charging technique.
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Affiliation(s)
- T Jang
- University of Michigan, Ann Arbor, MI, USA
| | - J Lim
- University of Michigan, Ann Arbor, MI, USA
| | - K Choo
- University of Michigan, Ann Arbor, MI, USA
| | - S Nason
- University of Michigan, Ann Arbor, MI, USA
| | - J Lee
- University of Michigan, Ann Arbor, MI, USA
| | - S Oh
- University of Michigan, Ann Arbor, MI, USA
| | - S Jeong
- University of Michigan, Ann Arbor, MI, USA
| | - C Chestek
- University of Michigan, Ann Arbor, MI, USA
| | | | - D Blaauw
- University of Michigan, Ann Arbor, MI, USA
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Jang T, Oak C, Jung M. P3.01-033 Detection of Epidermal Growth Factor Receptor Mutations with Plasma Sample Compared with Tumor Tissue Biopsy in Advanced Lung Adenocarcinoma. J Thorac Oncol 2017. [DOI: 10.1016/j.jtho.2017.09.1474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Spigel D, Bondarenko I, Losonczy G, Mezger J, Kalofonos H, Reck M, Palmero R, Jang T, Natale R, Sanborn R, Lai J, Kallinteris N, Tang M, Shan J, Gerber D. Top-line results from SUNRISE: A phase III, randomized, double-blind, placebo-controlled multicenter trial of bavituximab plus docetaxel in patients with previously treated stage IIIb/iv non-squamous non-small cell lung cancer. Ann Oncol 2016. [DOI: 10.1093/annonc/mdw435.44] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Kim Y, Oh I, Kim K, Jang T, Choi Y, Kim Y, Lee K, Shin K, Jung C, Yang S, Jang S, Ryu J, Yoo S, Yong S, Lee K, In K, Lee M. A Randomized Phase III Study of Docetaxel Plus Cisplatin Versus Pemetrexed Plus Cisplatin in First Line Non-Squamous Non-Small Cell Lung Cancer (Nsq-Nsclc). Ann Oncol 2014. [DOI: 10.1093/annonc/mdu438.49] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Artesi M, Kroonen J, Deprez M, Bredel M, Chakravarti A, Poulet C, Seute T, Rogister B, Bours V, Robe P, Liu SC, Chernikova S, Merchant M, Jang T, Zollner S, Kruschinski A, Ahn GO, Recht L, Brown M, Moyal ECJ, Delmas C, Taurand M, Mazoyer S, Farge M, Toulas C, Rao S, Thompson C, Cheng J, Haimovitz-Friedman A, Fuks Z, Kolesnick R, Wen Q, Jalilian L, Essock-Burns E, Li Y, Cha S, Chang S, Prados M, Butowski N, Nelson S, Ke C, Tran K, Di Donato AT, Ru N, Linskey ME, Limoli C, Zhou YH. RADIOBIOLOGY. Neuro Oncol 2013. [DOI: 10.1093/neuonc/not188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Oh SK, Song CG, Jang T, Kim KC, Jo YJ, Kwak JS. Reduction of gate leakage current on AlGaN/GaN high electron mobility transistors by electron-beam irradiation. J Nanosci Nanotechnol 2013; 13:1738-1740. [PMID: 23755582 DOI: 10.1166/jnn.2013.6987] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
This study examined the effect of electron-beam (E-beam) irradiation on the AIGaN/GaN HEMTs for the reduction of gate leakage. After E-beam irradiation, the gate leakage current significantly decreased from 2.68 x 10(-8) A to 4.69 x 10(-9) A at a drain voltage of 10 V. The maximum drain current density of the AIGaN/GaN HEMTs with E-beam irradiation increased 14%, and the threshold voltage exhibited a negative shift, when compared to that of the AIGaN/GaN HEMTs before E-beam irradiation. These results strongly suggest that the reduction of gate leakage current resulted from neutralization nitrogen vacancies and removing of oxygen impurities.
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Affiliation(s)
- S K Oh
- Department of Printed Electronics Engineering (WCU), Sunchon National University, Jeonnam 540-742, Korea
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Einert TR, Schmidt G, Binnig G, Balacescu O, Balacescu L, Rus M, Buiga R, Tudoran O, Todor N, Nagy V, Irimie A, Neagoe I, Yacobi R, Ustaev E, Berger RR, Barshack I, Kaur K, Henderson S, Cutts A, Domingo E, Woods J, Motley C, Dougherty B, Middleton M, Hassan B, Wang Y, Beasley E, Naley M, Schuh A, Tomlinson I, Taylor J, Planchard D, Lueza B, Rahal A, Lacroix L, Ngocamus M, Auger N, Saulnier P, Dorfmuller P, Le Chevalier T, Celebic A, Pignon JP, Soria JC, Besse B, Sun YH, Wang R, Li CG, Pan YJ, Chen HQ, Chouchane L, Shan J, Kizhakayil D, Aigha I, Dsouza S, Noureddine B, Gabbouj S, Mathew R, Hassen E, Chouchane L, Shan S, al-Rumaihi K, al-Bozom I, al-Said S, Rabah D, Farhat K, Kizhakayil D, Aigha I, Jakobsen Falk IA, Green KHZ, Lotfi K, Fyrberg A, Pejovic T, Li H, Mhawech-Fauceglia P, Hoatlin M, Guo MG, Huang M, Ge Y, Hess K, Wei C, Zhang W, Bogush TA, Dudko EA, Nureev MV, Kamensky AA, Polotsky BE, Tjulandin SA, Davydov MI, Caballero M, Hasmats J, Green H, Quanz M, Buhler C, Sun JS, Dutreix M, Cebotaru CL, Buiga R, Placintar AN, Ghilezan N, Balogh ZB, Reiniger L, Rajnai H, Csomor J, Szepesi A, Balogh A, Deak L, Gagyi E, Bodor C, Matolcsy A, Bozhenko VK, Rozhkova NI, Kudinova EA, Bliznyukov OP, Vaskevich EN, Trotsenko ID, Bozhenko VK, Rozhkova NI, Kharchenko NV, Kudinova EA, Bliznyukov OP, Kiandarian IV, Trotsenko ID, Pulito C, Terrenato I, Sacconi A, Biagioni F, Mottolese M, Blandino G, Muti P, Falvo E, Strano S, Mori F, Sacconi A, Ganci F, Covello R, Zoccali C, Biagini R, Blandino G, Strano S, Palmer GA, Wegdam W, Meijer D, Kramer G, Langridge J, Moerland PD, de Jong SM, Vissers JP, Kenter GG, Buist MR, Aerts JMFG, Milione M, de Braud F, Buzzoni R, Pusceddu S, Mazzaferro V, Damato A, Pelosi G, Garassino M, de Braud F, Broggini M, Marabese M, Veronese S, Ganzinelli M, Martelli O, Ganci F, Bossel N, Sacconi A, Fontemaggi G, Manciocco V, Sperduti I, Falvo E, Strigari L, Covello R, Muti P, Strano S, Spriano G, Domany E, Blandino G, Donzelli S, Sacconi A, Bellissimo T, Alessandrini G, Strano S, Carosi MA, Pescarmona E, Facciolo F, Telera S, Pompili A, Blandino G, de Vriendt V, de Roock W, di Narzo AF, Tian S, Biesmans B, Jacobs B, de Schutter J, Budzinska E, Sagaert X, Delorenzi M, Simon I, Tejpar S, Zhu Y, Wang HK, Ye DW, Denisov E, Tsyganov M, Tashireva L, Zavyalova M, Perelmuter V, Cherdyntseva N, Kim YC, Jang T, Oh IJ, Kim KS, Ban H, Na KJ, Ahn SJ, Kang H, Kim WJ, Park C, Abousamra NK, El-Din MS, Azmy EA. Diagnostics. Ann Oncol 2012. [DOI: 10.1093/annonc/mds161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Kim Y, Jang T, Oh I, Kim K, Ban H, Na K, Ahn S, Kang H, Kim W, Park C. P1.31 Snp Q787Q of Egfr Gene and Efficacy of Egfr-Tki in Patients With Non-Small Cell Lung Cancer. Ann Oncol 2012. [DOI: 10.1016/s0923-7534(20)31322-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Graubard M, Rohdenberg P, Jang T. Short answer question case series: the perils of urine toxicology testing. Arch Emerg Med 2011; 28:998-9. [DOI: 10.1136/emermed-2011-200276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Rohdenberg P, Shetty P, Jang T. Short answer question case series: treatment of persistent, refractory seizures. Arch Emerg Med 2011; 28:904-5. [DOI: 10.1136/emermed-2011-200275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Rohdenberg P, Graubard M, Jang T. Short answer question case series: postlytic gastrointestinal bleeding. Arch Emerg Med 2011; 28:815-6. [DOI: 10.1136/emermed-2011-200274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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20
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Wang C, Jang T, Cundiff C, Chauhan V. 275: Multi-Center Assessment of Sonography for Abdominal Pain. Ann Emerg Med 2007. [DOI: 10.1016/j.annemergmed.2007.06.261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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21
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Swartzberg J, Jang T, Naunheim R, Najand H, Chauhan V. 162: Incidence of Hypokalemia in Patients Presenting to the Emergency Department With Diabetic Ketoacidosis. Ann Emerg Med 2007. [DOI: 10.1016/j.annemergmed.2007.06.195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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22
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Schindler D, Jang T. Sonography for the Assessment of Small Bowel Obstruction. Acad Emerg Med 2007. [DOI: 10.1197/j.aem.2007.03.976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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23
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Ruggeri W, Jang T, Dyne P. Emergency Residents Training in Limited Biliary Sonography. Acad Emerg Med 2007. [DOI: 10.1197/j.aem.2006.10.079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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24
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Jang T, Aubin C, Dyne P. The Minimum Training Standard for Emergency Physicians Performing Focused Obstetric Ultrasonography. Ann Emerg Med 2005. [DOI: 10.1016/j.annemergmed.2005.06.295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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26
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Jung M, Kim J, Kim H, Oak C, Jang T, Jeon Y, Jeon C. PD-014 Relation between ERCC1 expression in sputum and survivalafter cisplatin-based chemotherapy in patients with non-small cell lung cancer. Lung Cancer 2005. [DOI: 10.1016/s0169-5002(05)80346-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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27
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Jung M, Kim H, Oak C, Jang T, Jeon Y, Jung T. P-209 Concurrent biweekly gemcitabine plus cisplatin chemotherapyand radiotherapy in patients with locally advanced non-small cell lung cancer. Lung Cancer 2005. [DOI: 10.1016/s0169-5002(05)80703-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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28
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Jang T, Kim H, Ok C, Ryu J, Jung M. P-503 Smoking history, and serum NSE level as prognostic factors inthe adenocarcinoma of lung cancer patients. Lung Cancer 2005. [DOI: 10.1016/s0169-5002(05)80996-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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31
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Recht LD, Salmonsen R, Rosetti R, Jang T, Pipia G, Kubiatowski T, Karim P, Ross AH, Zurier R, Litofsky NS, Burstein S. Antitumor effects of ajulemic acid (CT3), a synthetic non-psychoactive cannabinoid. Biochem Pharmacol 2001; 62:755-63. [PMID: 11551521 DOI: 10.1016/s0006-2952(01)00700-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
One of the endogenous transformation products of tetrahydrocannabinol (THC) is THC-11-oic acid, and ajulemic acid (AJA; dimethylheptyl-THC-11-oic acid) is a side-chain synthetic analog of THC-11-oic acid. In preclinical studies, AJA has been found to be a potent anti-inflammatory agent without psychoactive properties. Based on recent reports suggesting antitumor effects of cannabinoids (CBs), we assessed the potential of AJA as an antitumor agent. AJA proved to be approximately one-half as potent as THC in inhibiting tumor growth in vitro against a variety of neoplastic cell lines. However, its in vitro effects lasted longer. The antitumor effect was stereospecific, suggesting receptor mediation. Unlike THC, however, whose effect was blocked by both CB(1) and CB(2) receptor antagonists, the effect of AJA was inhibited by only the CB(2) antagonist. Additionally, incubation of C6 glioma cells with AJA resulted in the formation of lipid droplets, the number of which increased over time; this effect was noted to a much greater extent after AJA than after THC and was not seen in WI-38 cells, a human normal fibroblast cell line. Analysis of incorporation of radiolabeled fatty acids revealed a marked accumulation of triglycerides in AJA-treated cells at concentrations that produced tumor growth inhibition. Finally, AJA, administered p.o. to nude mice at a dosage several orders of magnitude below that which produces toxicity, inhibited the growth of subcutaneously implanted U87 human glioma cells modestly but significantly. We conclude that AJA acts to produce significant antitumor activity and effects its actions primarily via CB(2) receptors. Its very favorable toxicity profile, including lack of psychoactivity, makes it suitable for chronic usage. Further studies are warranted to determine its optimal role as an antitumor agent.
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Affiliation(s)
- L D Recht
- Department of Neurology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA.
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Kubiatowski T, Jang T, Lachyankar MB, Salmonsen R, Nabi RR, Quesenberry PJ, Litofsky NS, Ross AH, Recht LD. Association of increased phosphatidylinositol 3-kinase signaling with increased invasiveness and gelatinase activity in malignant gliomas. J Neurosurg 2001; 95:480-8. [PMID: 11565871 DOI: 10.3171/jns.2001.95.3.0480] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
OBJECT Glioblastoma multiforme is the most malignant of the primary brain tumors and aggressively infiltrates surrounding brain tissue, resulting in distant foci within the central nervous system, thereby rendering this tumor surgically incurable. The recent findings that both phosphatidylinositol 3-kinase (PI 3-K) and the phosphatase and tensin homolog (PTEN) regulate tumor cell invasiveness have led the authors to surmise that these lipid signaling molecules might play a role in regulating matrix metalloproteinases (MMPs), which are essential for tumor cell invasion. METHODS Using the C6 glioma cell line, which does not express measurable amounts of PTEN protein and in which in vitro invasiveness is MMP dependent, the authors determined that in vitro glioma cell invasiveness was significantly reduced when cells were preincubated overnight with LY294002 or wortmannin, two specific inhibitors of PI 3-K signaling. Next, using gelatin zymography, it was noted that these compounds significantly inhibited MMP-2 and MMP-9 activities. Moreover, the decrease in MMP activity correlated with the decrease in PI 3-K activity, as assessed by Akt phosphorylation. Finally, using semiquantitative reverse transcriptase-polymerase chain reaction, the authors demonstrated that LY294002 decreased messenger (m)RNA levels for both MMPs. Thus, these in vitro data indicate that PI 3-K signaling modulates gelatinase activity at the level of mRNA. Using immunostaining of phosphorylated Akt (p-Akt) as a measure of PI 3-K activity, the authors next assessed rat brains implanted with C6 cells. Compared with surrounding brain, there was marked p-Akt staining in C6 glioma cells and in neurons immediately adjacent to the tumor, but not in normal brain. The p-Akt staining in tumors was especially intense in perivascular areas. Using double-labeling techniques, colocalization of p-Akt with MMP-2 and MMP-9 was also noted in perivascular tumor areas. CONCLUSIONS The increase in p-Akt staining within these PTEN-deficient gliomas is consistent with what would be predicted from unchecked PI 3-K signaling. Furthermore, the immunohistochemically detected colocalization of p-Akt and MMP-2 and MMP-9 supports the authors' in vitro studies and the proposed linkage between PI 3-K signaling and MMP activity in gliomas.
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Affiliation(s)
- T Kubiatowski
- Department of Surgery, University of Massachusetts Medical Center, Worcester 01655, USA
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Abstract
Male hamsters were exposed to the female pheromone, aphrodisin (APH), its cloned protein backbone (rAPH), and the homologous lipocalin, beta-lactoglobulin (beta-LG). Of these, only APH elicited mating behavior. Enhanced c-fos protein was found in the nuclei of neurons in the accessory olfactory bulb (AOB) after exposure to these stimuli. Relative to beta-LG, both rAPH and APH produced significant increases in AOB labeling. The modest labeling elicited by rAPH was evenly distributed, but the heavier staining elicited by APH was concentrated in the caudal region of the AOB. Thus, pheromone receptor neurons in the basal compartment of the vomeronasal epithelium, which project to the caudal region of the AOB, may respond to APH and provide the input which drives mating behavior.
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Affiliation(s)
- T Jang
- Worcester Foundation for Biomedical Research Shrewsbury, MA 01545, USA
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Abstract
Aminooxyacetic acid, a potent inhibitor of the mitochondrial malate-aspartate shunt, was used to assess the role of mitochondrial energy metabolism in damaged brain of rats of different age groups. Three age groups--juvenile (< 1 month), young adult (3-4 months), and adult (7 months)--were subjected to examine the age-related aminooxyacetic acid effect. We measured the absolute concentrations of metabolites in perchloric acid extracts of rat striatum after intraperitoneal administration of aminooxyacetic acid using 1H NMR spectroscopy. Among aminooxyacetic acid-treated groups, a twofold increase of GABA concentration was observed in juveniles and young adults, and a threefold elevation of GABA level was observed in adults, whereas there were no significant differences of alanine and glutamate levels in all three aminooxyacetic acid-treated groups as compared with the age-matched controls. Statistically significant decreases of N-acetylaspartate, glutamine, and creatine levels were detected in treated adults. A statistically significant elevation of lactate concentration was found in the adult treated group. These data have demonstrated that the impairment of energy metabolism in rat striatum induced by aminooxyacetic acid can be revealed by quantitative in vitro 1H NMR spectroscopy and that aminooxyacetic acid produces age-dependent striatal abnormalities.
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Affiliation(s)
- C Chang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
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35
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Abstract
A critical assessment of perchloric acid (PCA) brain tissue extracts for precise identification and quantitation of brain metabolites using in vitro proton nuclear magnetic resonance (1H NMR) spectroscopy was studied. One pulse with a presaturation NMR experiment was used. The chemical shifts and coupling networks of the major brain metabolites as a function of pH were characterized by using individual model compounds and a model mixture solution. We found that the conditions of the PCA solution are essential for accurate interpretation of NMR spectra of brain metabolites. The maximum spectral resolution was obtained at pH 4.92. Caution is necessary when using high resolution 1H NMR spectroscopy to identify and quantify brain metabolites.
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Affiliation(s)
- C Chang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, Republic of China
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36
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Abstract
BACKGROUND Magnetic Resonance Imaging (MRI) has been widely used as a noninvasive diagnostic tool for obtaining morphological, metabolic, and functional information from tissue. However, its potential application in observing detailed structure comparable to that of the light microscope has not yet been fully explored. In order to evaluate the usefulness of MR microscopy, a high resolution three-dimensional (3-D) technique was applied to observe the laminar structure of the mammalian olfactory bulb (OB). METHODS Adult male hamsters (Mesocrecitus auratus) were used as an animal model. Hamster OB and the attached anterior olfactory nucleus were removed from the skull for the MRI examinations. The images were performed with a Bruker AMX-400 system equipped with microimaging accessories. T2 weighted 3-D spin echo sequence was used with a field of view of 9 mm and data matrix of 128*128*128. The in-plane resolution was 70*70*70 microns. Histological preparation, including vibratome sectioning at 40 microns and Nissl staining, were used for light microscopic evaluations and comparisons. RESULTS Five distinct layers from the superficial to the center of the OB were distinguished in the MR images of coronal, sagittal and horizontal slices. As compared to the histological sections at the corresponding cutting planes, the laminar structure of the OB displayed in the MR microscopic images correlated well with its counterparts. CONCLUSIONS MR microscopy is capable of detecting cellular variation of unsectioned and unstained tissue. It can also be easily applied to obtain spatial information with good resolution. It appears to provide a great potential for diagnostic pathology.
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Affiliation(s)
- C Chang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, ROC
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37
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Abstract
The somal shapes, dendritic features, and orientations of the neurons within the gustatory zone of the nucleus of the solitary tract were studied with the rapid Golgi method in the adult hamster. These Golgi studies complement previous quantitative morphometric analyses of the distributions of large and small neurons within the gustatory zone. Class 1 neurons are usually fusiform and possess long, relatively unbranched dendrites that often extend beyond the cytoarchitectonic boundaries of the gustatory zone. Class II neurons are multipolar and possess more dendrites that are significantly shorter than those of class I neurons. Both classes of neurons are spine poor. Computer-generated three-dimensional rotational analyses demonstrate that the dendritic arborizations of neurons of the gustatory zone are oriented preferentially in the horizontal plane. Dendrites extend in parallel or perpendicular to the solitary tract, the source of peripheral gustatory inputs, and appear to be positioned spatially to maximize synaptic interactions with these peripheral fibers. These Golgi studies also suggest that individual gustatory neurons may be influenced by incoming gustatory fibers that innervate separate populations of taste buds, a finding that is not predictable from the topographical organization of the gustatory zone.
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Affiliation(s)
- B J Davis
- Department of Cell Biology and Anatomy, University of Alabama, Birmingham 35294
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Davis BJ, Jang T. Tyrosine hydroxylase-like and dopamine beta-hydroxylase-like immunoreactivity in the gustatory zone of the nucleus of the solitary tract in the hamster: light- and electron-microscopic studies. Neuroscience 1988; 27:949-64. [PMID: 2908060 DOI: 10.1016/0306-4522(88)90198-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A quantitative electron-microscopic analysis has been conducted on the neurons within the gustatory zone of the nucleus of the solitary tract of the hamster. The most common group of neurons within the gustatory zone contains both large (X1) and small (X3) members that possess deeply invaginated nuclear profiles. These neurons have somal areas that average 113 micron2 (range 34-281 micron2) and a value of somal area/nuclear area that averages 2.2. Other large and small neurons that have non-invaginated nuclear profiles are also observed. The larger (X2) neurons average 151 micron2 (range 49-487 micron2) and have much cytoplasm and associated membranous organelles that is reflected in a mean value of somal area/nuclear area of 2.6. Members of the X2 group are the largest neurons in the gustatory zone. The smaller (X4) group contains the smallest neurons in the gustatory zone of the nucleus of the solitary tract, averages 50 micron2 (range 16-103 micron2), shows almost no perinuclear cytoplasm and has a mean value of somal area/nuclear area of only 1.5. These findings are consistent with and expand upon the results of similar studies at the light-microscopic level. This grouping has been used to explore the association of tyrosine hydroxylase-like and dopamine beta-hydroxylase-like immunoreactivities with specific populations of neurons that are known to be distributed across the various levels of the gustatory zone. At the light-microscopic level, numerous well-defined and intensely labelled tyrosine hydroxylase-like immunoreactive somata of various morphologies and sizes are observed. Quantification at the electron-microscopic level indicates that 10-15% of the neurons encountered in the dorsal and intermediate levels of the gustatory zone are immunoreactive. The ventral level of the gustatory zone contains few immunoreactive neurons. Tyrosine hydroxylase-like immunoreactive neurons possess either non-invaginated or invaginated nuclear profiles and their somal areas average 106 and 142 micron2, respectively. On the bases of size and ultrastructural features, these immunoreactive somata are assigned to the two groups (X1 and X2) of large neurons within the gustatory portion of the nucleus of the solitary tract. In general, small neurons are not immunoreactive. The distribution of dopamine beta-hydroxylase-like immunoreactivity has also been examined in adjacent sections in order to reveal the presence of any putative noradrenergic neurons in the gustatory zone.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- B J Davis
- Department of Cell Biology and Anatomy, University of Alabama, Birmingham 35294
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