• 환경위생공학
• /
• 제9권1호
• /
• pp.67-75
• /
• 1994

Formaldehyde has been in widespread industrial use since World War II . Numerous sources of formaldehyde are present in the indoor environment. Additionally, the current trend toward tighter, more energy efficient buildings with lower ventilation rates has led to increase concentrations of this and other pollutants generated indoors. In this paper, the field survey was carried out once a month from January to MarctL 1994 to measure indoor and outdoor formaldehyde concentration in several underground locations in Seoul. The results could be summarized as follows : 1. At Yang- jae underground shopping center, the mean formaldehyde concentration was 77.8ppb for indoor and 68.4ppb for outdoor. At Ban- po underground shopping center, it was 175.8ppb for indoor and 127.3ppb for outdoor. At Jam- shil underground shop ping center, it was 135.2ppd for indoor and 34.6ppb for outdoor. Indoor the No.2 sub way line, it was 105.6ppb. The formaldehyde concentration using Berge equation was as follows : At Yang- jae underground shopping center, the mean formaldehyde concentration was 85.99ppb for indoor and 72.75ppb for outdoor At Ban- po underground shopping center, it was 254. 17ppb for indoor and 138.14ppb for outdoor. At Jam- shil underground shopping center, it was 249.13ppb for indoor and 36.87ppb for outdoor. Indoor the No.2 subway line, it was 131.73ppb. 3, The result of correlation analysis indicated that the relationship between temperature and formaldehyde concentration is very high( $\gamma $= 0.831 ∼ 0.974). 4. Also, the relationship between humidity and formaldehyde concentration is variant ($\gamma $ = 0.246 ∼0.999). 5. The mean formaldehyde concentration indoor and outdoor Ban- po underground shop ping center and indoor Jam- shil underground shopping center and indoor the No.2 sub way line exceed the American Society of Heating, Refrigeration, Air- conditioning Engineers( ASHRAE) stflndard of 100ppb(120 $\mu $g/m$^{3}$).

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제9권7호
• /
• pp.2389-2413
• /
• 2015

High data rates in long-term evolution (LTE) networks can affect the mobility of networks and their performance. The speed and motion of user equipment (UE) can compromise seamless connectivity. However, a proper handover (HO) decision can maintain quality of service (QoS) and increase system throughput. While this may lead to an increase in complexity and operational costs, self-optimization can enhance network performance by improving resource utilization and user experience and by reducing operational and capital expenditure. In this study, we propose the self-optimization of HO parameters based on fuzzy logic control (FLC) and multiple preparation (MP), which we name FuzAMP. Fuzzy logic control can be used to control self-optimized HO parameters, such as the HO margin and time-to-trigger (TTT) based on multiple criteria, viz HO ping pong (HOPP), HO failure (HOF) and UE speeds. A MP approach is adopted to overcome the hard HO (HHO) drawbacks, such as the large delay and unreliable procedures caused by the break-before-make process. The results of this study show that the proposed method significantly reduces HOF, HOPP, and packet loss ratio (PLR) at various UE speeds compared to the HHO and the enhanced weighted performance HO parameter optimization (EWPHPO) algorithms.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권6호
• /
• pp.2397-2402
• /
• 2015

Previous studies have shown that miR-454 plays an important role in a variety of biological processes in various human cancer cells. However, the underlying mechanisms of this microRNA in colorectal cancer (CRC) cells remain largely unknown. In the present study, we investigated the miR-454 role in CRC cell proliferation. We found that miR-454 expression is markedly upregulated in CRC tissues and CRC cells compared with the matched tumor adjacent tissues and the FHC normal colonic cell line. Ectopic expression of miR-454 promoted the proliferation and anchorage-independent growth of CRC cells, whereas inhibition of miR-454 reduced this effect. Bioinformatics analysis further revealed cylindromatosis (CYLD), a putative tumor suppressor as a potential target of miR-454. Data from luciferase reporter assays showed that miR-454 directly binds to the 3'-untranslated region (3'-UTR) of CYLD mRNA and repressed expression at both transcriptional and translational levels. In functional assays, CYLD-silenced in miR-454-in-transfected SW480 cells have positive effect to promote cell proliferation, suggesting that direct CYLD downregulation is required for miR-454-induced CRC cell proliferation. In sum, our data provide compelling evidence that miR-454 functions as an onco-miRNA, playing a crucial role in the promoting cell proliferation in CRC, and its oncogenic effect is mediated chiefly through direct suppression of CYLD expression.

• Journal of Microbiology and Biotechnology
• /
• 제25권3호
• /
• pp.358-365
• /
• 2015

ε-Poly-L-lysine (ε-PL) is a homopolymer of L-lysine molecules connected between the epsilon amino and alpha carboxyl groups. This polymer is currently used as a natural preservative in food. Insufficient biomass is a major problem in ε-PL fermentation. Here, to improve cell growth and ε-PL productivity, various nitrogen-rich nutrients were supplemented into flask cultures after 16 h cultivation, marking the onset of ε-PL biosynthesis. Yeast extract, soybean powder, corn powder, and beef extract significantly improved cell growth. In terms of ε-PL productivity, yeast extract at 0.5% (w/v) gave the maximum yield (2.24 g/l), 115.4% higher than the control (1.04 g/l), followed by soybean powder (1.86 g/l) at 1% (w/v) and corn powder (1.72 g/l) at 1% (w/v). However, supplementation with beef extract inhibited ε-PL production. The optimal time for supplementation for all nutrients examined was at 16 h cultivation. The kinetics of yeast-extract-supplemented cultures showed enhanced cell growth and production duration. Thus, the most commonly used two-stage pH control fed-batch fermentation method was modified by omitting the pH 5.0-controlled period, and coupling the procedure with nutrient feeding in the pH 3.9-controlled phase. Using this process, by continuously feeding 0.5 g/h of yeast extract, soybean powder, or corn powder into cultures in a 30 L fermenter, the final ε-PL titer reached 28.2 g/l, 23.7 g/l, and 21.4 g/l, respectively, 91.8%, 61.2%, and 45.6% higher than that of the control (14.7 g/l). This describes a promising option for the mass production of ε-PL.

• 한국정보과학회논문지:정보통신
• /
• 제37권1호
• /
• pp.27-34
• /
• 2010

본 논문에서는 네트워크 트래픽의 수동적 측정치 분석을 통해 잘 알려진 장거리 상관관계가 광역 네트워크의 능동적 측정치에도 존재하는지 여부를 관련 분석법을 통하여 검정하고자 한다. 이를 위하여 PingER 프로젝트를 통하여 측정된 광역 네트워크 트래픽의 대표적인 능동적 측정치인 RTT(Round Trip Time)와 RTT의 변동성 시계열 데이터에 대하여 분석을 수행하였다. RTT 시계열 데이터는 장거리 상관관계 혹은 1/f 노이즈의 특성을 보였으며, RTT의 고차원 변화량으로 정의된 변동성은 로그정규분포를 따르며 변동성에 대한 장거리 상관관계는 고려하는 시간 간격이 짧은 경우 장거리 상관관계를 보이고, 시간 간격이 긴 경우에는 장거리 상관관계 혹은 1/f 노이즈를 따름을 밝혔다. 본 연구를 통해 볼 때 장거리 상관관계는 비단 패킷 도착의 시간 간격 등과 같은 수동적 측정뿐만 아니라 RTT와 같은 능동적 측정에서도 나타나는 특징이며, 특히 능동적 측정에는 수동적 측정에는 잘 나타나지 않는 1/f 노이즈 특성이 존재함을 밝혔다.

• 한국통신학회논문지
• /
• 제36권6A호
• /
• pp.577-586
• /
• 2011

현대 디지털 통신 시스템에서는 여러 가지 열화 조건을 극복하기 위하여 거의 모든 시스템에서 오류정정 부호를 사용하며, 최근에는 반복적인 복호 기법으로 우수한 복호 성능 도출이 가능한 터보부호나 저밀도 패리티 검사부호 등을 사용하는 시스템이 늘고 있는 추세이다. 특히 반복적인 복호 방법으로 성능을 향상 시키는 부호를 다중안테나 시스템에서 사용하기 위해서는 수신단에서 송선 신호를 검출할 때 연판정된 채널 이득값의 계산이 필수적으로 요구된다. 본 논문에서는 반복 복호 기법을 사용하는 다중안테나 시스템에서 효과적으로 연판정 값을 검출하는 방법에 대해 살펴보고, 여러 가지 MIMO 검출 방법에 대하여 그 유도 과정을 제시한다. 또한, 유도된 연판정 검출 방법에 대한 시뮬레이션 결과를 제시하여, 제안된 방식이 적은 복잡도로 우수한 성능을 얻을 수 있음을 보인다.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권10호
• /
• pp.4271-4274
• /
• 2014

The epithelial to mesenchymal transition (EMT) is a key step during embryonic morphogenesis and plays an important role in drug resistance and metastasis in diverse solid tumors. We previously reported that 48 h treatment of anti-cancer drug doxorubicin could induce EMT in human gastric cancer BGC-823 cells. However, the long term effects of this transient drug treatment were unknown. In this study we found that after 48 h treatment with $0.1{\mu}g/ml$ doxorubicin, most cells died during next week, while a minor population of cells survived and formed colonies. We propagated the surviving cells in drug free medium and found that these long term cultured drug survival cells (abbreviated as ltDSCs) retained a mesenchymal-like cell morphology, and expressed high levels of EMT-related molecules such as vimentin, twist and ${\beta}$-catenin. The expression of chromatin reprogramming factors, Oct4 and c-myc, were also higher in ltDSCs than parental cells. We further demonstrated that the protein level of p300 was upregulated in ltDSCs, and inhibition of p300 by siRNA suppressed the expression of vimentin. Moreover, the ltDSCs had higher colony forming ability and were more drug resistant when compared to parental cells. Our results suggested that an epigenetic mechanism is involved in the EMT of ltDSCs.

• Journal of Preventive Medicine and Public Health
• /
• 제50권2호
• /
• pp.133-140
• /
• 2017

Objectives: The purpose of this study was to describe the source, length, number of views, and content of the most widely viewed Zika virus (ZIKV)-related YouTube videos. We hypothesized that ZIKV-related videos uploaded by different sources contained different content. Methods: The 100 most viewed English ZIKV-related videos were manually coded and analyzed statistically. Results: Among the 100 videos, there were 43 consumer-generated videos, 38 Internet-based news videos, 15 TV-based news videos, and 4 professional videos. Internet news sources captured over two-thirds of the total of 8 894 505 views. Compared with consumer-generated videos, Internet-based news videos were more likely to mention the impact of ZIKV on babies (odds ratio [OR], 6.25; 95% confidence interval [CI], 1.64 to 23.76), the number of cases in Latin America (OR, 5.63; 95% CI, 1.47 to 21.52); and ZIKV in Africa (OR, 2.56; 95% CI, 1.04 to 6.31). Compared with consumer-generated videos, TV-based news videos were more likely to express anxiety or fear of catching ZIKV (OR, 6.67; 95% CI, 1.36 to 32.70); to highlight fear of ZIKV among members of the public (OR, 7.45; 95% CI, 1.20 to 46.16); and to discuss avoiding pregnancy (OR, 3.88; 95% CI, 1.13 to 13.25). Conclusions: Public health agencies should establish a larger presence on YouTube to reach more people with evidence-based information about ZIKV.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권15호
• /
• pp.6335-6338
• /
• 2015

Background: Cancers have dysfunctional redox regulation resulting in production of reactive oxygen species (ROS), damaging DNA, RNA and free NTPs, and causing the accumulation of oxidative nucleic acids in cytoplasm. The major types are 8-oxo-7,8-dihydroguanine(8-oxoGsn) in RNA and 8-oxo-7,8-dihydro-2' deoxyguanosine(8-oxodGsn) in Mt-DNA. The MTH1 protein sanitizes oxidized nucleotide pools from NTPs to monophosphates, preventing the occurrence of transversion mutations. This study concerned cytoplasmic 8-oxodGsn/Gsn and MTH1 expression in gastric cancer and para-cancer tissues and elucidated roles of nucleic-acid oxidation and anti-oxidation. Materials and Methods: A polymer HRP detection system was used to detect 8-oxo-Gsn/dGsn and MTH1 expression in 51 gastric cancer and para-cancer tissue samples. Analyses of patient clinical and pathological data were also performed. Results: The expression of MTH1 and the 8-oxo-dGsn/Gsn ratio were significantly higher in cancer tissues than para-cancer tissues (P<0.05). Cytoplasmic 8-oxo-Gsn and MTH1 were both found to positively correlate (P<0.05) with tumor differentiation, while no significant associations were found with gender, age, invasion depth, lymph node metastasis and clinical stage (P>0.05). Conclusions: We found 8-oxo-dGsn/Gsn and MTH1 are both highly expressed in gastric cancer tissues, especially in well differentiated lesions. In addition, oxidated mtDNA is prevalently expressed in gastric cancers, while 8-oxo-Gsn expression in cytoplasmic RNA is a bit lower, but more selectively.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권11호
• /
• pp.6507-6512
• /
• 2013

The purpose of this study was to evaluate the associations of CYP1A1 genetic polymorphisms with the risk of developing esophageal cancer (EC). A case-control study was carried out in a Chinese population in which 157 hospital based EC cases and 157 population based healthy controls with 1:1 match by age and sex were included. PCR based restriction fragment length polymorphisms (PCR-RFLP) were used to detect genotypes in case and control groups. For the CYP1A1 Ile/Val polymorphism, comparing with wild genotype Ile/Ile, both the heterozygote genotype Ile/Val and the combined variant genotype Ile/Val+Val/Val increased the risk of esophageal cancer (OR: 2.05, 95%CI: 1.19-3.54, OR: 1.86, 95%CI: 1.11-3.12). No significant association was found between the CYP1A1 MspI polymorphism and EC. According to analysis of combined genotypes, the TC/AG combined genotype which contained both variant alleles of these two polymorphisms increased the risk of developing EC (OR: 2.12, 95%CI: 1.16-3.85). Our results suggested that genetic polymorphisms of CYP1A1 may increase the susceptibility to EC.