• The Korean Journal of Nuclear Medicine Technology
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• v.21 no.1
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• pp.50-53
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• 2017

Purpose The change in uniformity due to the decreasement in dose should be known. $^{57}Co$ sealed sources are easy to manage and use as QC sources replacing $^{99m}Tc$. Overlapping sealed sources are expected to show variations in dose due to attenuation between sealed sources. Materials and Methods A total of three experiments were conducted. The first experiment is to observe the change in the degree of senescence of the $^{57}Co$ sealed source. The second experiment is to compare the single source and overlaped source at similar doses. In the third experiment, the sources of different doses were compared on each other to determine the changes due to the attenuation between the overlapping sources. Results The results of the first experiment did not exceed the acceptable range. but each crew showed a difference. There was no statistically significant difference in the measurement of uniformity on second and third experiment Conclusion It is believed that a $^{57}Co$ sealed source can be used as a superimposed source. It is not only economical but also convenient to use. daily uniformity measurements will help reduce scan time and speed up the testing process.

• Applied Chemistry for Engineering
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• v.25 no.1
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• pp.14-19
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• 2014

Nanocomposites based on poly(methyl methacrylate) (PMMA)/poly(vinylidene fluoride) (PVDF) and poly(ethylene terephthalate) (PET)/(PVDF) blended with carbon fibers (CF) and carbon nanotube (CNT) were prepared by melt mixing in the twin screw extruder. Morphologies of the PMMA/PVDF/CF/CNT and PET/PVDF/CF/CNT nanocomposites were investigated using SEM. The aggregation of CNT was observed in PMMA/PVDF/CF/CNT nanocomposites while the good dispersion of CNT was shown in PET/PVDF/CF/CNT nanocomposites. In SEM image of PET/PVDF/CF/CNT nanocomposite, the CNT were mainly located at the PET domain of phase-separated PET/PVDF blend due to the ${\pi}-{\pi}$ interaction between the phenyl ring of PET and graphite sheet of the CNT's surface. In addition, a fairly good compatibility between PET/PVDF matrix and CF was shown in the SEM image. In the case of PET/PVDF nanocomposites blended with the co-addition of CF and CNT, the volume electrical resistivity decreased while no change was observed in PMMA/PVDF/CF/CNT composites. The degree of CNT dispersion in morphology results was consistent with the electrical conductivity results. From the DSC results, the crystallization temperature (Tc) of PET/PVDF/CF/CNT nanocomposites increased due to the co-addition of CF and CNTs acting as a nucleating agent. Flexural modulus of PET/PVDF/CF/CNT were sharply enhanced due to increasing the interaction between PET and CF.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3405-3416
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• 2012

The purpose of this study was to find out the effects of music rope-skipping on health fitness, blood lipids and growth-related factors in male middle school students. For this purpose, twenty subjects were participated in this study and the participants were 'After School Class' boys in B middle school located in Gimhae City. They divided into exercise group(n=10) and control group(n=10). Exercise group conducted 45minutes per a day, four times a week for 12 weeks. And the control group continued their normal life. The results were as follows; First, in exercise group, lean body mass, muscular strength, muscular endurance, cardiovascular endurance and flexibility were all significantly increased after program execution. But %body fat was significantly decreased. In control group, muscular strength, muscular endurance and cardiovascular endurance were significantly increased. There were significant differences in lean body mass, %body fat, muscular strength and flexibility between two groups after program execution. Second, in exercise group, HDL-C was significantly increased after program execution. In control group, TG was significantly decreased. But HDL-C was significantly increased. There were no significant differences in all blood lipids(TC, TG, HDL-C and LDL-C) between two groups after program execution. Third, in exercise group, GH and IGF-I were significantly increased after program execution. In control group, IGF-I was significantly decreased. There were significant differences in IGF-I between two groups after program execution. These results indicate that music rope-skipping is effective to improve lean body mass, muscular strength, flexibility, GH and IGF-I in normal middle school male students.

• Journal of Nutrition and Health
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• v.50 no.3
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• pp.236-245
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• 2017

Purpose: The aim of this study was to assess the effects of guava leaf extract (GLE) supplementation on antioxidant enzyme activity and expression of endothelial nitric oxide synthase (eNOS) mRNA in ovariectomized rats. Methods: All animals were randomly assigned to four groups (n = 7 for each group): non-ovariectomized control (Sham), the ovariectomized control (OVX), ovariectomy + 150 mg/kg b.w. of GLE ($OVX{\cdot}GL$), and ovariectomy + 300 mg/kg b.w. of GLE ($OVX{\cdot}GH$). Treatment groups were administered GLE for 8 weeks every day. Results: Body weight gain was significantly reduced in the $OVX{\cdot}GL$ group compared with the OVX group (p < 0.05). The level of serum $17{\beta}$-estradiol (E2) was significantly lower in the OVX groups than the Sham group (p < 0.05). Serum triglyceride (TG) and HDL-cholesterol levels were not significantly different between all groups. However, serum total cholesterol (TC) level was significantly reduced in the $OVX{\cdot}GH$ group compared with the OVX group (p < 0.05). Serum free fatty acid (FFA) level and liver TG level were significantly reduced in both $OVX{\cdot}GL$ and $OVX{\cdot}GH$ groups compared with the OVX group (p < 0.05). Furthermore, serum glutathione peroxidase (GPx) activity was significantly elevated in the GLE groups (p < 0.05). The mRNA expression level of GPx was not affected by ovariectomy. However, administration of GLE resulted in significantly increased nuclear factor erythroid 2-related factor (Nrf2) and catalase (CAT) mRNA expression levels in the liver (p < 0.05). In addition, liver nitric oxide (NO) level was significantly reduced in the $OVX{\cdot}GH$ group compared with the OVX group (p < 0.05). Expression level of endothelial nitric oxide synthase (eNOS) was significantly elevated in the $OVX{\cdot}GH$ group compared with the OVX group (p < 0.05). Conclusion: These results suggest that GLE could have protective effects in OVX rats by stimulating eNOS expression and improving the antioxidant defense system.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.899-907
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• 2017

The purpose of this study is to investigate effects of floor exercise on senior fitness test, blood lipids and arterial stiffness in elderly women with metabolic syndrome. Forty one elderly women with metabolic syndrome were randomly assigned to a exercsie group(n=23) or control goup(n=18). The exercise group performed floor exercise for 12 weeks, 3times per week. Exercise intensity was increased gradually from 30%-60% of heart rate reserve. Senior fitness, blood lipids profile and arterial stiffness were measured pre and post the 12 weeks intervention. Senior fitness(lower body strength, upper body strength, flexibility, aerobic capacity and body composition(%fat, LBM, WC)), Blood lipids(TC, TG, HDL-C and LDL-C) and Arterial stiffness(PWV) were significantly improved in the exercise group after floor exercise, however no changes were confirmed in the control group. These findings indicates that 12 weeks of floor exercise improves senior fitness, blood lipids and arterial stiffness in elderly women with metabolic syndrome. Thus, this study provides evidence that floor exercise is important methods to improve metabolic syndrome health. And it can reduce metabolic syndrome symptoms risk in elderly women with metabolic syndrome.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.4
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• pp.95-103
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• 2009

In this paper, a generation method of transmit and receive beamforming vectors based on base station cooperation is proposed which maximizes the user SINR in mobile cellular multi-user MIMO systems. There are two main sources of interference which deteriorate the performance of the system, i.e. the inter-user interference caused by the usage of the same radio resource for multiple users in the system, and the inter-cluster interference from neighboring base stations which are not participating in cooperative transmission. The proposed scheme cancels out the inter-user interference by using the block diagonalization(BD) method, and mitigate the inter-cluster interference by using optimal transmit and receive beamforming vectors based on optimal combining(OC) with the statistic information of inter-cluster interference. We perform computer simulations to verify the performance of the proposed scheme, and compare the result to the conventional performance obtained from utilizing the receiver side information only or utilizing the information from neither sides. The performance evaluations are conducted not only over the independent MIMO channels, but over correlated MIMO channels to demonstrate the robustness of the proposed scheme over the channels with correlation among antennas.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.5
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• pp.139-145
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• 2009

Recently P2P (Peer-to-Peer) networks and applications have been expanded to various field. However, because the construction of P2P network did not influence a underlying network topology or property, it may be inefficient. Especially, this inefficiency is more serious in MANET because MANET has narrow bandwidth and energy constraint. When we use a proactive routing protocol in MANET, we can know hop counts between two nodes. And, we can construct a P2P overlay network using this hop count information. However, In case of using hop count only, we can avoid a interference path selection problem and a zig-zag problem. We propose a method of improving P2P contents distribution using virtual positions. We calculate virtual positions from hop counts using the trigonometry. This method solves a interference path selection problem and a zig-zag problem. This method also allows a P2P network to influence underlying network topology. We adopt this method to a network which uses a virtual geographic routing, a proactive routing protocol, or a reactive routing protocol. We show that our proposed methods improve P2P contents distribution performance over MANET through a simulation.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.2
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• pp.103-112
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• 2010

In sensor networks, because sensors are deployed in an unprotected environment, they are prone to be targets of compromise attack, If the number of compromised nodes increases considerably, the key management in the network is paralyzed. In particular, compromise of Cluster Heads (CHs) in clustered sensor networks is much more threatening than that of normalsensors. Recently, rekeying schemes which update the exposed keys using the keys unknown to the compromised nodes are emerging. However, they cause some security and efficiency problems such as single group key employment in a cluster, passive eviction of compromised nodes, and excessive communication and computation overhead. In this paper, we present a proactive rekeying scheme using renewals of duster organization for clustered sensor networks. In the proposed scheme, each sensor establishes individual keys with neighbors at network boot-up time, and these keys are employed for later transmissions between sensors and their CH. By the periodic cluster reorganization, the compromised nodes are expelled from network and the individual keys employed in a cluster are changed continuously. Besides, newly elected CHs securely agree a key with sink by informing their members to sink, without exchangingany keying materials. The simulation results shows that the proposed scheme remarkably improves the confidentiality and integrity of data in spite of the increase of compromised nodes. Also, they show that the proposed scheme exploits the precious energy resource more efficiently than SHELL.

• Journal of dental hygiene science
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• v.9 no.5
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• pp.525-530
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• 2009

The purpose of this study was to evaluate color change and enamel surface changes using the plasma arc light source during tooth bleaching treatments. Twenty-four extracted bovine incisors were selected and embedded in the resin blocks. All the specimens were highly polished and discolored with commercial $COCK^{(R)}$. High concentration carbamide peroxide with and without plasma arc were used for bleaching. Specimens were bleached for 1 hour per week during 3 weeks. Color and enamel surface changes were determined with colorimeter (TC-8600A), microhardness tester(MXT-a7), scanning electron microscope(S-4200). All the collected data analyzed with paired t-test, t-test and one-way ANOVA. After the bleaching, both groups showed the color changes(${\Delta}E^*$). Microhardness of two group decreased after tooth bleaching. The SEM evaluation of enamel surface of both group showed a similar morphology of decalcification after tooth bleaching. Office bleaching using the plasma arc application with 35% carbamide peroxide can increase the color change. Office bleaching using the high concentration of carbamide peroxide and plasma arc also detract the outer surface of enamel. It is recommended that careful procedures are needed during office bleaching with high concentration of carbamide peroxide and light source.

• Journal of the Korean Child Neurology Society
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• v.26 no.4
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• pp.272-275
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• 2018

KBG syndrome is a rare neurodevelopmental disorder characterized by intellectual disability, skeletal anomalies, short stature, craniofacial dysmorphism, and macrodontia. ANKRD11 gene mutation and 16q24.3 microdeletion have been reported to cause KBG syndrome. Here, we report two patients with ANKRD11 mutations who initially presented with neurologic symptoms such as developmental delay and seizures. Patient 1 was a 23-month-old boy who presented with a global developmental delay. Language delay was the most dominant feature. He had hypertelorism, hearing impairment, and behavior problems characterized as hyperactivity. A c.1903_1907delAAACA (p.Lys635GInfsTer26) mutation in ANKRD11 was identified with diagnostic exome sequencing. Patient 2 was a 14-month-old boy with developmental delay and seizure. He also had atrial septum defect, and ventricular septal defect. Generalized tonic seizures began at the age of 8 months. Electroencephalography showed generalized sharp and slow wave pattern. Seizures did not respond to antiepileptic drugs. A loss of function mutation c.5350_5351delTC (p.ser1784HisfsTer12) in ANKRD11 was identified with diagnostic exome sequencing. In both cases, characteristic features of KBG syndrome such as short stature or macrodontia, were absent, and they visited the hospital due to neurological symptoms. These findings suggest that more patients with mild phenotypes of KBG syndrome are being recognized with advances in diagnostic exome sequencing genetic technologies.