• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.8
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• pp.1-7
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• 2007

Class AB bipolar linear transconductors for high frequency applications ire proposed. They consist of a voltage follower, a resistor, and a current follower. The follower circuits are realized by translinear cells or unity-gain buffers. The proposed transconductors are simulated using an 8 GHz bipolar transistor-arrary parameter. Simulation results show that the transconductor using translinear cells has better linearity than one using unity-gain buffers whereas the latter has better temperature stability and higher input resistance than the former. In order to test their high frequency applicability, the transconductors are used to implement an 4th order IF bandpass filter.

• Journal of Advanced Navigation Technology
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• v.9 no.2
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• pp.164-169
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• 2005

In this paper, the high efficiency Doherty power amplifier using adaptive bias technique has been designed and realized for 2.3GHz Wibro applications. The RF performances of the Doherty power amplifier using adaptive bias technique have been compared with those of a class AB amplifier alone, and conventional Doherty amplifier. The Maximum PAE of designed Doherty power amplifier with adaptive bias technique has been 36.6% at 34.0dBm output power. The proposed Doherty power amplifier showed an improvement 1dB at output power and 7.6% PAE than a class AB amplifier alone.

• Transactions on Electrical and Electronic Materials
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• v.2 no.4
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• pp.1-6
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• 2001

In this paper, a 1.5 V high-gain high-frequency CMOS complementary operational amplifier is presented. The input stage of op-amp is designed for supporting the constant transconductance on the Input stage by consisting of the parallel-connected rail-to-rail complementary differential pairs. And consisting of the class-AB rail-to-rail output stage using the concept of elementary shunt stage and the grounded-gate cascode compensation technique for improving the low PSRR which was a disadvantage in the general CMOS complementary input stage, the load dependence of open loop gain and the stability of op- amp on the output load are improved, and the high-gain high-frequency operation can be achieved. The designed op-amp operates perfectly on the complementary mode with the 180° phase conversion for a 1.5 V supply voltage, and shows the DC open loop gain of 84 dB, the phase margin of 65°, and the unity gain frequency of 20 MHz. In addition, the amplifier shows the 0.1 % settling time of .179 ㎲ for the positive step and 0.154 ㎲ for the negative step on the 100 mV small-signal step, respectively, and shows the total power dissipation of 8.93 mW.

• Journal of Advanced Navigation Technology
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• v.21 no.1
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• pp.66-71
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• 2017

This paper describes implementation of a 165 MHz, 5 kW RF high power amplifier (HPA) for particle accelerator applications. The HPA consists of a drive amplifier for main amplifiers driving, sixteen 600 W class-AB push-pull power amplifier pallets and Wilkinson power divider/combiner using lumped LC components, which are divided/combined power amplifier pallet outputs. To detected the amplifier circuit of normal and reflected output power conditions, we used a bidirectional coupler. To radiate heat of main power amplifier, we were used an water-cooled copper plates to go through a water for radiation of heat. The HPA of center frequency 165 MHz has archived an efficiency of 62.5 % at 5 kW of power level experimentally.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.5
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• pp.255-259
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• 2003

Dendritic cells (DCs) play a critical role in various immune responses involving $CD4^+$ T cells and have been used to generate anti-tumor immunity. Chemotherapy induces severe side effects including immunosuppression in patients with cancer. Although immunosuppression has been studied, the effects of anticancer drugs on DCs are not fully determined. In this study, we demonstrated that CD40 activation strongly protected DCs from 5-fluorouracil (5-FU) or mitomycin C-induced apoptosis. DCspecific surface markers, including CD11c and major histocompatibility complex (MHC) class II, were used for identifying DCs. CD 40 activation with anti-CD40 mAb significantly enhanced the viability of DCs treated with 5-FU or mitomycin C, assayed by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide). Fluorescence staining and analysis clearly confirmed the enhancing effect of anti-CD40 mAb on the viability of DCs, suggesting that CD40 activation may transduce critical signals for the viability of DCs. Annexin V staining assay showed that CD40 significantly protected DCs from 5-FU or mitomycin C-induced apoptosis. Taken together, this study shows that CD40 activation with anti-CD40 mAb has strong anti-apoptosis effect on DCs, suggesting that CD40 activation may overcome the immunosuppression, especially downregulation of number and function of DCs in chemotherapy-treated cancer patients.

• IMMUNE NETWORK
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• v.22 no.1
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• pp.4.1-4.22
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• 2022

In the era of immunotherapeutic control of cancers, many advances in biotechnology, especially in Ab engineering, have provided multiple new candidates as therapeutic immuno-oncology modalities. Bispecific Abs (BsAbs) that recognize 2 different antigens in one molecule are promising drug candidates and have inspired an upsurge in research in both academia and the pharmaceutical industry. Among several BsAbs, T cell engaging BsAb (TCEB), a new class of therapeutic agents designed to simultaneously bind to T cells and tumor cells via tumor cell specific antigens in immunotherapy, is the most promising BsAb. Herein, we are providing an overview of the current status of the development of TCEBs. The diverse formats and characteristics of TCEBs, in addition to the functional mechanisms of BsAbs are discussed. Several aspects of a new TCEB-Blinatumomab-are reviewed, including the current clinical data, challenges of patient treatment, drawbacks regarding toxicities, and resistance of TCEB therapy. Development of the next generation of TCEBs is also discussed in addition to the comparison of TCEB with current chimeric antigen receptor-T therapy.

• The korean journal of orthodontics
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• v.9 no.1
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• pp.105-110
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• 1979

In order to define what the average Class I malocclusion looks like, 72 Class I malocclusions were compared with corresponding measurements from 90 cases of normal occlusion sample. This sample was obtained from the Department of Orthodontics, Infirmary of Seoul National University. 1. SNA, Fac(NP) to SN measurements were significantly different from the normal occlusions and smaller than the normal occlusion means. 2. 'Y' axis to SN, Mandibular plane to SN, $\underline{1}$ to Occlusal plane, $\bar{1}$ to NB(linear) measurements were significantly different from the normal occlusions and larger than the normal occlusions. 3. ANB, Occlusal plane to SN, AB to Occlusal plane, $\underline{1}$ to SN, $\bar{1}$ to SN, $\bar{1}$ to Occlusal plane measurements showed no significant difference between the means.

• The korean journal of orthodontics
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• v.25 no.2 s.49
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• pp.153-163
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• 1995

In this study, Receiver Operating Characteristic(ROC) analysis was used to evaluate the ability of cephalometric measurements to identify patients with Class III malocclusions. ROC analysis is the method for determining the validity of a diagnostic measure and for evaluating the relative value of diagnostic tests. The sample consisted of 496 patients with malocclusion. Class III malocclusion is defined as the dental relationship for which The mesiobuccal groove of the lower first molar is deviated mesially from the mesiobuccal cusp of the upper first molar. Of the total sample of 496 patients, 245 had Class III malocclusions. 16 cephalometric measurements were selected, each of which was treated as a diagnostic test. The ROC curves were generated for each cephalometric measurement with intervals of $1.0^{\circ}$ for angular measurements, 1.0mm for linear measurements. The area under the ROC curves was measured for direct comparison among different diagnostic tests. The results were as follows; 1. The 'Wits' appraisal was found to be a better diagnostic criterion for the presence of Class III malocclusion than any other commonly'used cephalometric measurement. 2. AB plane angle, ANB angle, App-Bpp distance, AF-BF distance, APDI, Distance of point A and Pog to N perpendicular, maxillomandibular differential had high diagnostic value. 3. Cephalometric measurements which evaluate the position of the mandible had moderate diagnostic value. 4. Cephalometric measurements related to the maxilla discriminated least between patients with and without Class III malocclusion.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.1
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• pp.14-19
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• 2001

When the high power transistor is used for amplifier in microwave frequency, the bias of transistor is usually AB-class or B-c1ass because of power efficiency. The sweet spot point having small IMD signal compared with near neighborhood exicts frequently in the high power transistor using AB class bias or B-class bias. On the sweet spot, the magnitude and phase of the main and IMD signal of HPA output change as the input signal power change, respective the relative phase on the sweet spot changes rapidly. If we know exactly the magnitude and phase characteristics of IMD signal, we can design a more adequate linearizer and understand the characteristics of transistor. In this paper the magnitude and phase of the main and IMD signal of HPA output on the sweet spot are measured using the designed hardware.

• The korean journal of orthodontics
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• v.23 no.3 s.42
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• pp.341-358
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• 1993

This study was investigated to evaluate the morphologic characteristics of deepbite tendency as multiple factors. The subjects consisted of 60 control subjects(male 25, female 35) and 137 deephite patients(68 male, 69 female). The deepbite group was composed of 4 subgroups(Class I 44, Class II div. 1 40, Class II div. 2 13, Class III 40). The mean age was 21.57 year for the control group 21 year for deepbite group lateral cephalograph in centric occlusion were taken, traced, and digitized for each subject. The statistically computerized analysis was carried out with SAS program. The results were as follows ; 1. In deepbite group, saddle angle is lesser than that of normal group. 2. The vertical dysplasia is prominent on anterior lower face and is closely related with mandibular form and inclination. 3. Without consideration of sagittal relationship, the dental factors such as curve of Spee, interincisal angle, U1 to upper lip length were prominent in the deepbite group. 4. Although there were individual variances in the perioral soft tissue profile, the lip presented more protruded pattern. 5. There was no significant difference in hyoid bone position and inclination between normal and deepbite group. 6. The multivariate discriminant analysis between normal and Class I deepbite group showed that curve of Spee, AB-MP angle, interincisal angle, articular agnle were critical in the determination of deepbite as multiple factors.