• Asian Journal of Atmospheric Environment
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• v.6 no.4
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• pp.259-267
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• 2012

To clarify the effects of black carbon (BC) particles on growth and gas exchange rates of Asian forest tree species, the seedlings of Fagus crenata, Castanopsis sieboldii, Larix kaempferi and Cryptomeria japonica were exposed to BC particles with sub-micron size for two growing seasons from 1 June 2009 to 11 November 2010. The BC particles deposited after the exposure to BC were observed on the foliar surface of the 4 tree species. At the end of the experiment, the amount of BC accumulated on the foliar surface after the exposure to BC aerosols were 0.13, 0.69, 0.32 and 0.58 mg C $m^{-2}$ total leaf area in F. crenata, C. sieboldii, L. kaempferi and C. japonica seedlings, respectively. In August 2010, the exposure to BC particles did not significantly affect net photosynthetic rate under any light intensity, stomatal diffusive conductance to water vapour ($g_s$), stomatal limitation of photosynthesis, response of $g_s$ to increase in vapour pressure deficit and leaf temperature under light saturated condition in the leaves or needles of the seedlings. These results suggest that the BC particles deposited on the foliar surface did not reduce net photosynthesis by shading, did not increase leaf temperature by absorption of irradiation light, and did not induce plugging of stomata in the leaves or needles of the seedlings. There were no significant effects of BC particles on the increments of plant height and stem base diameter during the experimental period and the whole-plant dry mass at the end of the experiment. These results indicate that the exposure to BC particles with sub-micron size for two growing seasons did not significantly affect the growth and leaf or needle gas exchange rates of F. crenata, C. sieboldii, L. kaempferi and C. japonica seedlings.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.2
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• pp.145-151
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• 2004

This paper presents a fully integrated 5 GHz band low phase noise LC tank VCO. The implemented VCO is tuned by integrated PN diodes and tuning rage is 5.01∼5.30 GHz with 0∼3 V control voltage. For improved phase noise performance, a LC filtering technique is adapted. The measured phase noise is -87.8 dBc/Hz at 100 kHz offset frequency and -111.4 dBc/Hz at 1 MHz offset frequency which is excellent performance. Moreover phase noise is improved by 5 dB after employing the LC filter. It is the first experimental result in field of InGaP/GaAs HBT VCOs. The figure of merit of the fabricated VCO with LC filter is -172.1 dBc/Hz. It is the best result among 5 GHz InGaP HBT VCOs. Moreover this work shows lower DC power consumption, higher output power and more fixed output power compared with previous 4, 5 GHz band InGaP HBT VCOs.

• Nutrition Research and Practice
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• v.4 no.3
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• pp.196-202
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• 2010

To investigate the neuroprotective effects of bovine colostrums (BC), we evaluate the ability of consuming BC after focal brain ischemia/reperfusion injury rat model to reduce serum cytokine levels and infarct volume, and improve neurological outcome. Sprague-Dawley rats were randomly divided into 4 groups; one sham operation and three experimental groups. In the experimental groups, MCA occlusion (2 h) and subsequent reperfusion (O/R) were induced with regional cerebral blood flow monitoring. One hour after MCAO/R and once daily during the experiment, the experimental group received BC while the other groups received 0.9% saline or low fat milk (LFM) orally. Seven days later, serum pro-inflammatory cytokine (IL-$1{\beta}$, IL-6, and TNF-${\alpha}$) and anti-inflammatory cytokine (IL-10) levels were assessed. Also, the infarct volume was assessed by using a computerized image analysis system. Behavioral function was also assessed using a modified neurologic severity score and corner turn test during the experiment. Rats receiving BC after focal brain I/R showed a significant reduction (-26%/-22%) in infarct volume compared to LFM/saline rats, respectively (P < 0.05). Serum IL-$1{\beta}$, IL-6, and TNF-${\alpha}$ levels were decreased significantly in rats receiving BC compared to LFM/saline rats (P < 0.05). In behavioral tests, daily BC intake showed consistent and significant improvement of neurological deficits for 7 days after MCAO/R. BC ingestion after focal brain ischemia/reperfusion injury may prevent brain injury by reducing serum pro-inflammatory cytokine levels and brain infarct volume in a rat model.

• Journal of Mushroom
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• v.13 no.3
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• pp.185-191
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• 2015

This research was carried out to determine the differences of physiological activites between Grifola frondosa of log cultivation(LC) and Grifola frondosa of bottle cultivation(BC). Total flavonoids content, total phenolics content, electron donating ability(EDA), nitrite-scavenging ability(NSA), SOD-like activity and inhibitory effect of Xanthine oxidase were examined. The highest value of total flavonoid content is $5.96{\pm}0.81mg/g$ in water extract from Grifola frondosa of log cultivation at $40^{\circ}C$ (LC-W40) but, one of total phenolics compound is $44.53{\pm}0.89mg/g$ in water extract from Grifola frondosa of bottle cultivation at $40^{\circ}{\cdots}$ (BC-W40). The EDA using DPPH of BC-W40 extract showed the highest value of $97.14{\pm}0.71%$. Nitrite-scavenging ability was $62.55^{\circ}{\ae}0.36%$ in extract from Grifola frondosa of BC-W40 at pH 1.2. The value was SOD-like activity showed the highest value of $18.95^{\circ}{\ae}1.39%$ in extract from LC-W40. Xanthine oxidase inhibitory activity was the highest value of $54.31{\pm}0.40%$ in extract from Grifola frondosa BC-W40, and dependent on concentrations. These results showed that a the antioxidant effects of Grifola frondosa is excellent. However, physiological activities of Grifola frondosa were not depend on caltivation method regulary, and were different according to kind of solvents, concentraitions and physialogical factors examined such as EDA, SOD-like activity and NSA.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.3
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• pp.122-128
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• 2023

This paper proposes two kinds of single-balanced direct conversion quadrature receivers using selfoscillating LMVs in which the voltage-controlled oscillator (VCO) itself operates as a mixer while generating an oscillation. The two LMVs are complementary coupled and series coupled to generate the quadrature oscillating signals, respectively. Using a 65 nm CMOS technology, the proposed quadrature receivers are designed and simulated. Oscillating at around 2.4 GHz frequency, the complementary coupled quadrature receiver achieves the phase noise of -28 dBc/Hz at 1KHz offset and -109 dBc/Hz at 1 MHz offset frequency. The other series coupled receiver achieves the phase noise of -31 dBc/Hz at 1KHz offset and -109 dBc/Hz at 1 MHz offset frequency. The simulated voltage conversion gain of the two single-balanced receivers is 37 dB and 45 dB, respectively. The double-sideband noise figure of the two receivers is 5.3 dB at 1 MHz offset. The quadrature receivers consume about 440 μW dc power from a 1.0-V supply.

• Journal of Periodontal and Implant Science
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• v.46 no.3
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• pp.176-196
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• 2016

Purpose: We sought to evaluate the effectiveness of bone substitutes in circumferential periimplant defects created in the rabbit tibia. Methods: Thirty rabbits received 45 implants in their left and right tibia. A circumferential bone defect (6.1 mm in diameter/4 mm depth) was created in each rabbit tibia using a trephine bur. A dental implant ($4.1mm{\times}8.5mm$) was installed after the creation of the defect, providing a 2-mm gap. The bone defect gaps between the implant and the bone were randomly filled according to the following groups: blood clot (CO), particulate Bio-Oss$^{(R)}$ (BI), and Bio-Oss$^{(R)}$ Collagen (BC). Ten animals were euthanized after periods of 15, 30, and 60 days. Biomechanical analysis by means of the removal torque of the implants, as well as histologic and immunohistochemical analyses for protein expression of osteocalcin (OC), Runx2, OPG, RANKL, and TRAP were evaluated. Results: For biomechanics, BC showed a better biological response ($61.00{\pm}15.28Ncm$) than CO ($31.60{\pm}14.38Ncm$) at 30 days. Immunohistochemical analysis showed significantly different OC expression in CO and BC at 15 days, and also between the CO and BI groups, and between the CO and BC groups at 60 days. After 15 days, Runx2 expression was significantly different in the BI group compared to the CO and BC groups. RANKL expression was significantly different in the BI and CO groups and between the BI and BC groups at 15 days, and also between the BI and CO groups at 60 days. OPG expression was significantly higher at 60 days postoperatively in the BI group than the CO group. Conclusions: Collectively, our data indicate that, compared to CO and BI, BC offered better bone healing, which was characterized by greater RUNX2, OC, and OPG immunolabeling, and required greater reversal torque for implant removal. Indeed, along with BI, BC presents promising biomechanical and biological properties supporting its possible use in osteoconductive grafts for filling peri-implant gaps.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.4
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• pp.313-323
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• 2017

Objectives: This study aimed to assess exposure to black carbon(BC) among forklift operators and to identify environmental and occupational factors influencing their BC exposure. Methods: We studied a total of 23 forklift operators from six workplaces manufacturing paper boxes. A daily BC exposure assessment was conducted during working hours from January to April 2017. A micro-aethalometer was used to monitor daily BC exposure, and information on work activities was also obtained through a time-activity diary(TAD) and interviews. BC exposure records were classified into four categories influencing BC exposure level: working environment, workplace, forklift operation, and job characteristics. Analysis of variance(ANOVA) was used to compare average BC exposure levels among the four categories and the relationships between potential factors and BC exposure were analyzed using a multiple linear regression model. Results: The operators' daily exposure was $12.9{\mu}g/m^3$(N=9,148, $GM=7.5{\mu}g/m^3$) with a range: $0.001-811.4{\mu}g/m^3$. The operators were exposed to significantly higher levels when they operate a forklift in a room ${\leq}20,000m^3$($AM=12.3{\mu}g/m^3$), in indoor workplaces($AM=16.3{\mu}g/m^3$), when they operate a forklift manufactured before 2006 ($AM=13.2{\mu}g/m^3$), a forklift with a loading limit of four-tons($AM=27.1{\mu}g/m^3$), with a roll and bale type clamp($AM=17.1{\mu}g/m^3$), and with no particulate filter($AM=15.7{\mu}g/m^3$). Conclusions: Occupational factors including temperature, smoking, season, daytime, room volume($m^3$), location of operating, and manufacturing era and model of forklift influenced the BC exposure of forklift operators. The results of this study can be used to minimize the BC exposure of forklift operators.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.8
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• pp.964-969
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• 2007

A regulated low phase noise differential colpitts VCO(Voltage Controlled Oscillator) for mobile RFID system is presented. The differential colpitts VCO meets the dense reader environment specifications. The VCO use a $0.35{\mu}m$ technology and achieves tuning range $1.55{sim}2.053 GHz$. Measuring 910 MHz frequency divider output, phase noise performance is -106 dBcMz and -135dBc/Hz at 40 kHz and 1MHz offset, respectively. 5-bit digital coarse-tuning and accumulation type MOS varactors allow for 28.2% tuning range, which is required to cover the LO frequency range of a UHF Mobile RFID system, Optimum design techniques ensure low VCO gain(<45 MHz/V) for good interoperability with the frequency synthesizer. To the author' knowledge, this differential colpitts VCO achieves a figure of merit(FOM) of 1.93dB at 2-GHz band.

• Journal of Genetic Medicine
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• v.9 no.1
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• pp.1-10
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• 2012

About 7% of all breast cancer (BC) cases result from a genetic predisposition, and approximately 1,000 patients develop hereditary BC (HBC) every year in Korea. BRCA1 and BRCA2 are the primary genes underlying HBC. The average cumulative risks in BRCA1 mutation carriers at 70 years of age are 65% (95% confidence interval 44-78%) for BC and 39% (18-54%) for ovarian cancer (OC). The corresponding estimates for BRCA2 are 45% (31-56%) and 11% (2.4-19%), respectively. The penetrance of BRCA mutations is not the same between patients and can depend on factors such as race and birth-cohort. The Korean Hereditary Breast Cancer (KOHBRA) study is a large prospective nationwide study that includes 39 participating centers. Between May 2007 and May 2010, the first phase of the KOHBRA study was planned and fulfilled successfully. The primary aim of phase I was to estimate the prevalence of BRCA1/2 mutations and OC among a high-risk group of patients with HBC and their families. According to data collected during phase I of the study, the prevalence and penetrance of BRCA mutations were comparable to corresponding data from Western countries. For the second phase of the KOHBRA study, we are currently investigating a Korean BRCA mutation prediction model, prognostic factors in BRCA-related BC, environmental/genetic modifiers, and implementing a genetic counseling network. The final goal of the KOHBRA study is to create clinical practice guidelines for HBC in Korea. In this article, I review the genetics of HBC, summarize the characteristics of Korean HBC, and discuss current and future HBC research in Korea.

• Molecules and Cells
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• v.41 no.3
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• pp.188-197
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• 2018

Benzidine, a known carcinogen, is closely associated with the development of bladder cancer (BC). Epithelial-mesenchymal transition (EMT) is a critical pathophysiological process in BC progression. The underlying molecular mechanisms of mitogen-activated protein kinase (MAPK) pathway, especially extracellular regulated protein kinases 5 (ERK5), in regulating benzidine-induced EMT remains unclarified. Hence, two human bladder cell lines, T24 and EJ, were utilized in our study. Briefly, cell migration was assessed by wound healing assay, and cell invasion was determined by Transwell assay. Quantitative PCR and western blot were utilized to determine both gene expressions as well as protein levels of EMT and MAPK, respectively. Small interfering RNA (siRNA) was transfected to further determine ERK5 function. As a result, the migration and invasion abilities were enhanced, epithelial marker expression was decreased while mesenchymal marker expression was increased in human BC cell lines. Meanwhile, benzidine administration led to activation of ERK5 and activator protein 1 (AP-1) proteins, without effective stimulation of the Jun N-terminal kinase (JNK) or p38 pathways. Moreover, Benzidine-induced EMT and ERK5 activation were completely suppressed by XMD8-92 and siRNAs specific to ERK5. Of note, ERK1/2 was activated in benzidine-treated T24 cells, while benzidine-induced EMT could not be reversed by U0126, an ERK1/2 inhibitor, as indicated by further study. Collectively, our findings revealed that ERK5-mediated EMT was critically involved in benzidine-correlated BC progression, indicating the therapeutic significance of ERK5 in benzidine-related BC.