Authors:Jin Kim, Hyung Lee, Jei-Won Yeon, Yongju Jung and Ji Kim
High surface area, ordered nanoporous carbon (CMK-3) and its chelating polymer composites were successfully prepared and utilized
for the removal of U(VI) from aqueous solutions. Carboxymethylated polyethyleneimine (CMPEI) with a strong chelating property
was introduced to the pore surface and inner pores of CMK-3 substrate. CMPEI-modified CMK-3 composite (CMPEI/CMK-3) was characterized
by scanning electron microscopy and nitrogen sorption. U(VI) sorption capacity was significantly improved by the surface modification
of CMK-3 by CMPEI. The CMPEI/CMK-3 showed enormously increased sorption capacities, compared with those of previous sorbents
(e.g., surface-functionalized silicas). In particular, the CMPEI/CMK-3 showed a significantly high uranium retention property
while allowing only about 1% U(VI) to leach out over a 4 month time period, when treated with polyacrylic acid.
Authors:Jong-Hwa Moon, Sun-Ha Kim, Yong-Sam Chung and Young-Jin Kim
The k0-standardization method (k0-NAA) is known as one of the most remarkable progresses of the NAA with its many advantages. For the application of k0-NAA method at the NAA #1 irradiation position where the neutrons are well thermalized in the HANARO research reactor, KAERI,
Korea, the determination of the reactor neutron spectrum parameters such as α and f have been carried out. The measured values of α and f using the “Cd-ratio” triple monitor method were 0.127±0.022 and 1010±70, respectively. To evaluate the applicability of k0-NAA in our analytical system, the analysis of three kinds of SRMs was executed. The analytical results showed that the relative
error of most of the elements was less than 10% and the U-scores were within 2. It is turned out that the procedure of the k0-NAA in the HANARO research reactor is available for a practical application in the environmental fields.
Authors:Yong-Sam Chung, Jong-Hwa Moon, Sun-Ha Kim, Sang-Hoon Kang and Young-Jin Kim
To enhance the applicability of the nuclear analytical technique in the field of industry and the environment, the inorganic
elemental content of the bottom ash from a municipal solid waste incinerator was determined by instrumental neutron activation
analysis. Bottom ash samples were monthly collected from an incinerator located at a metropolitan city in Korea, strained
through a 5 mm sieve, dried by an oven and pulverized by an agate mortar. The samples were irradiated at the NAA #1 irradiation
hole (thermal neutron flux: 2.92·1013 n·cm−2·s−1) in the HANARO research reactor of the Korea Atomic Energy Research Institute and the irradiated samples were measured by
a HP Ge gamma-ray spectrometer. Thirty-three elements including As, Cr, Cu, Fe, Mn, Sb and Zn were analyzed by an absolute
method. The quality control was conducted by a simultaneous analysis with NIST standard reference materials. The average concentrations
of the major elements such as Ca, Fe, Al, Na, Mg, K and Ti measured in the sample were 19.9%, 4.85%, 3.79%, 2.11%, 1.84%,
1.22% and 1.02%, respectively. In addition, the concentrations of the hazardous metals like Zn, Cu, Cr, Sb and As were 0.77%,
0.31%, 729 mg·kg−1, 116 mg·kg−1 and 22.2 mg·kg−1, respectively.
Authors:Yong-Sam Chung, Sun-Ha Kim, Jong-Hwa Moon, Sung-Yeol Baek, Young-Jin Kim, Hark-Rho Kim, Il-Jin Park and Kyung-Sik Min
A fast pneumatic transfer system for an instrumental neutron activation analysis and delayed neutron counting system were
reconstructed with new designs of a functional improvement at the HANARO research reactor in 2006. The design, conception,
operation and control of these systems are described. Also the experimental characteristic parameters by a functional operation
test and an irradiation test of these systems, such as the transfer time, the neutron flux, the temperature of the irradiation
position with an irradiation time, the radiation dose rate when the rabbit is returned, etc., are reported to provide a user
information as well as for the management and safety of the reactor.
Authors:Yeon-Jin Kim, Jae A. Lim, Ji Yoon Lee, Sohee Oh, Sung Nyun Kim, Dai Jin Kim, Jong Eun Ha, Jun Soo Kwon and Jung-Seok Choi
Background and aims
Internet gaming disorder (IGD) is characterized by a loss of control and a preoccupation with Internet games leading to repetitive behavior. We aimed to compare the baseline neuropsychological profiles in IGD, alcohol use disorder (AUD), and obsessive–compulsive disorder (OCD) in the spectrum of impulsivity and compulsivity.
A total of 225 subjects (IGD, N = 86; AUD, N = 39; OCD, N = 23; healthy controls, N = 77) were administered traditional neuropsychological tests including Korean version of the Stroop Color–Word test and computerized neuropsychological tests, including the stop signal test (SST) and the intra–extra dimensional set shift test (IED).
Within the domain of impulsivity, the IGD and OCD groups made significantly more direction errors in SST (p = .003, p = .001) and showed significantly delayed reaction times in the color–word reading condition of the Stroop test (p = .049, p = .001). The OCD group showed the slowest reading time in the color–word condition among the four groups. Within the domain of compulsivity, IGD patients showed the worst performance in IED total trials measuring attentional set shifting ability among the groups.
Both the IGD and OCD groups shared impairment in inhibitory control functions as well as cognitive inflexibility. Neurocognitive dysfunction in IGD is linked to feature of impulsivity and compulsivity of behavioral addiction rather than impulse dyscontrol by itself.
Authors:Ji-Won Chun, Chang-Hyun Park, Jin-Young Kim, Jihye Choi, Hyun Cho, Dong Jin Jung, Kook-Jin Ahn, Jung-Seok Choi, Dai-Jin Kim and In Young Choi
Background and aims
Although the Internet has provided convenience and efficiency in many areas of everyday life, problems stemming from Internet use have also been identified, such as Internet gaming disorder (IGD). Internet addiction, which includes IGD, can be viewed as a behavioral addiction or impulse control disorder. This study investigated the altered functional and effective connectivity of the core brain networks in individuals with IGD compared to healthy controls (HCs).
Forty-five adults with IGD and 45 HCs were included in this study. To examine the brain networks related to personality traits that influence problematic online gaming, the left and right central executive network (CEN) and the salience network (SN) were included in the analysis. Also, to examine changes in major brain network topographies, we analyzed the default mode network (DMN).
IGD participants showed lower functional connectivity between the dorsal lateral prefrontal cortex (DLPFC) and other regions in the CEN than HC participants during resting state. Also, IGD participants revealed reduced functional connectivity between the dorsal anterior cingulate cortex and other regions in the SN and lower functional connectivity in the medial prefrontal cortex of the anterior DMN. Notably, in IGD individuals but not HC individuals, there was a positive correlation between IGD severity and effective connectivity and a positive correlation between reward sensitivity and effective connectivity within the ventral striatum of the SN.
Problematic online gaming was associated with neurofunctional alterations, impairing the capacity of core brain networks.
Authors:Mi Jung Rho, Jo-Eun Jeong, Ji-Won Chun, Hyun Cho, Dong Jin Jung, In Young Choi and Dai-Jin Kim
Background and aims
Problematic Internet game use is an important social issue that increases social expenditures for both individuals and nations. This study identified predictors and patterns of problematic Internet game use.
Data were collected from online surveys between November 26 and December 26, 2014. We identified 3,881 Internet game users from a total of 5,003 respondents. A total of 511 participants were assigned to the problematic Internet game user group according to the Diagnostic and Statistical Manual of Mental Disorders Internet gaming disorder criteria. From the remaining 3,370 participants, we used propensity score matching to develop a normal comparison group of 511 participants. In all, 1,022 participants were analyzed using the chi-square automatic interaction detector (CHAID) algorithm.
According to the CHAID algorithm, six important predictors were found: gaming costs (50%), average weekday gaming time (23%), offline Internet gaming community meeting attendance (13%), average weekend and holiday gaming time (7%), marital status (4%), and self-perceptions of addiction to Internet game use (3%). In addition, three patterns out of six classification rules were explored: cost-consuming, socializing, and solitary gamers.
This study provides direction for future work on the screening of problematic Internet game use in adults.
Authors:Euihyeon Na, Inyoung Choi, Taek-Ho Lee, Hyeseon Lee, Mi Jung Rho, Hyun Cho, Dong Jin Jung and Dai-Jin Kim
Background and aims
Although Internet gaming disorder (IGD) has been investigated in detail, minimal research has been conducted regarding the influence of different game genres on IGD. The aim of this study is to compare the characteristics of members of game genre-specific groups with IGD and to identify factors associated with IGD status in each group in a large sample of adults.
Internet games were categorized into four genres: real-time strategy games, massive multiplayer online role-playing games (MMORPG), sport games, and first-person shooter (FPS) games. Participants (n = 2,923) who usually played one of these games completed an anonymous online survey that collected sociodemographic, game usage pattern, and psychopathological assessment data.
MMORPG and FPS game players more frequently met the criteria for IGD than participants in the other two groups. Differences between the IGD-suspected gamers within the genre-specific groups were observed for a few items, such as average game-playing time and the subscales of the behavioral activation system; however, the factors that contributed to the development of IGD within each game genre-specific group were found to be considerably different.
Discussion and conclusions
The findings of this study suggest that IGD is a stable psychiatric diagnosis encompassing users of a broad range of game genres. In addition, the development of strategies for the prevention of and early intervention on individuals at high risk for developing IGD may require consideration of the distinct characteristics identified as effective predictors of IGD in users of each game genre.
Authors:Ha-Yeon Kim, Gi-Hoon Lee, Chung-Hwan Jun, Kang-Jin Park, Sung-Bum Cho, Jin-Woong Kim and Young-Eun Joo
Metastasis to the ampulla of Vater from renal cell carcinoma (RCC) is rarely encountered. We present the case of a 50-year-old male admitted with complaints of right upper quadrant pain and jaundice. The medical history consisted of a right radical nephrectomy, right adrenalectomy, and brain mass excision for RCC and metastasis. An esophagogastroduodenoscopy revealed a round ampullary mass with ulceration. An abdominal computed tomography scan revealed an enhancing mass in the ampulla of Vater, total pancreas, and left adrenal gland. Pathologic examination of a biopsy specimen was compatible with metastatic RCC of the clear cell type. A percutaneous transhepatic cholangiogram revealed complete obstruction of the distal common bile duct. A metal stent was inserted for bile drainage via the percutaneous transhepatic route. Patients with a history of RCC should undergo a careful long-term follow-up to detect and evaluate metastasis to usual and unusual sites.
Authors:Lina Han, Soo-Jin Choi, Moon-Seok Park, Seon-Myong Lee, Yu-Jin Kim, Moon-Il Kim, Binyuan Liu and Dae-Won Park
In this study, a series of imidazolium-based ionic liquids (ILs) having carboxylic acid moieties were synthesized and used as new homogeneous catalysts to synthesize cyclic carbonates from CO2 and epoxides. Even in the absence of any co-catalyst and organic solvent, carboxylic-acid-functionalized ILs showed better catalytic activity in the coupling reaction of CO2 and styrene oxide for the production of styrene carbonate than did hydroxyl-functionalized ILs and conventional ILs without any functional moieties. A detailed investigation was carried out on a variety of factors that affected the reactivity, such as the alkyl chain length and the molecular composition of IL molecules including the halide ions. The effect of various reaction parameters such as reaction time, temperature, CO2 pressure and catalyst amount was also investigated in detail. The mechanism underlying the enhanced rate of the cycloaddition reaction in the presence of carboxylic-acid-functionalized ILs was proposed.