• Biotechnology and Bioprocess Engineering:BBE
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• 제5권2호
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• pp.84-91
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• 2000

Mycopasma contamination of tissue culture cells easily evades detection and, thus, represents a continous therat to cell biologists. In case where infected cell can not simply be replaced, attempts have to be made to eradicate mycoplacma from the tissue culture cells. A variety of anti-microbial agents have been shown to be toxic to mycoplasma strains ; however, cell associated mycoplasma are often protected from antibiotics at concentrations shown to be effective in vitro. Antibiotic concentrations high enough to be lethal to cell as sociated mycoplasmas frequently are also detrimentrations to the host cells, while moderately increased antibiotic levels tolerated by the host cells often lead to only temporary growth suppression and/or to the emergence of mycoplasma strains resistanct even to high concentrations of the antibiotis applied. Hare, a genetic approach for the elimination of mycoplasma from tissue culture cells that overcomes thens limitations is described. By expression of a selection marker conferring resistance to an otherwise toxic agent, Acholeplasma laidlawii infected BHK-21 cells used as the model system were enabled to temporarily tolerate antibiotic concentrations high enough to be lethal to cell associated mycopalsma while leaving the host cells unharmed. Upon successful mycoplasma eradicated, cultvation of the cured host cells in the absence of the selective agent yielded revertant cell clones that had regained susceptibillity to the toxic agent. Cressation of the selection marker expression was shown to result from the loss of the selection marker DNA, which is a consequence of the fact that the stable and permanent integration of foreign DNA in eucaryotic cell chrosomes is highly inefficient. Thus, the cells were cured from mycoplasma yet remained biochemically unaltered.

• 대한치과의사협회지
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• 제55권4호
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• pp.276-283
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• 2017

Maxillary sinus squamous cell carcinoma is a relatively rare disease, comprising only 3% of malignant diseases of head and neck. As the growth rate is high and its prognosis is poor compared to others, the 5-year survival rate of maxillary sinus squamous cell carcinoma(MSSCC) is 23.4-49%. We introduce two rare clinical cases of squamous cell carcinoma originated from maxillary sinus of which symptoms include toothache and gingival swelling. On clinical examinations of both patients, deep periodontal pockets on upper right posterior teeth were detected. On panoramic images, the bony destruction of the maxillary sinus and its surrounding structures were not obvious and only alveolar bone loss was noted. It is difficult to diagnose MSSCC at an early stage due to symptoms of tooth pain and gingival swelling that are similar to that of periodontal diseases. However, if the symptoms do not improve after routine treatment of upper teeth, dentists should bear in mind of underlying malignant mass as differential diagnosis, thus early detection of the lethal disease. The aim of this study is to caution dental practitioners that malignancies have a potential to mimic periodontal diseases by introducing two cases of maxillary sinus squamous cell carcinoma presented as periodontitis.

• 한국동물위생학회지
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• 제24권1호
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• pp.43-50
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• 2001

Swine proliferative enteritis(SPE) caused by inかsoma intracellularis is a common enteric disaese of grower and finisher pig. Swine affected with SPE show variable clinical signs including diarrhea, weight loss, aberrant growth and death. The characteristic lesion of ileitis at necropsy is marked thickening of the last section of the small intestine. The inner lining of the thickened intestine proliferates almost like a cancer and curved rod bacteria(L intracellularis) are always seen inside the intestinal wall. Infected swine shed the organism in the feces. Isolation and growth of pure L intracellularis in vitro requires a suitable cell culture. This procedure is difficult and not a practical means of diagnosis, thus the polymerase chain reaction(PCR) test of feces can be used to determine whether a pig is shedding the infective organism. A sensitive assay based on amplification of a 319bp DffA fragment of the L intracellularis of Swine proliferative enteritis was attempted for the detection of the organism in the 62 feces of swine. L intracellularis was identified on three herds and detected in 6 fecal samples, representing a infection rate of 9.7%. The PCR was very sensitive and specific on the individual level. The PCR technique could be very useful for the diagnosis of this disease.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권8호
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• pp.1860-1875
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• 2013

In this paper, we present a comparative performance evaluation of the sampling frequency synchronization method that eliminates the initial sampling frequency offset (SFO) to reduce the overall synchronization time in Digital Radio Mondiale (DRM) receivers. To satisfy the advanced synchronization performance requirements of DRM receivers, we introduce the conventional DRM synchronization method (Method 1) and another method (Method 2), which does not perform the initial sampling frequency synchronization in the conventional synchronization method (both methods are mentioned later in this paper). To demonstrate the effectiveness of the performance evaluation, analytical expressions for frame detection are derived and simulations are provided. Based on the simulations and numerical analysis, our result shows that Method 2, with a negligible performance loss, is robust to the effects of the initial sampling frequency synchronization even if SFO is present in the DRM signal. In addition, we verify that the inter-cell differential correlation used between reference cells is robust to the effect of the initial SFO.

• 대한한의학회지
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• 제25권4호
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• pp.95-107
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• 2004

Objective : The inappropriate or excessive apoptosis has been known to be associated with neurodegenerative disorders including intracranial hemorrhage(ICH). Paeoniae radix, in traditional Korean medicine, has played its role as blood­nourisher and yin-astringent. In the present study, the effect of Paeoniae radix on the inhibition of neurodegeneration in the brain of rats after artificial ICH and on the resulting apoptosis was investigated. Methods : 30 rats were divided into 6 equal groups ; the sham-operation group, the hemorrhage-induction group, the hemorrhage-induction with 10, 50, 100, and 200 mg/kg Paeoniae radix-treated group, respectively. Stereotactic surgery was performed and collagenase was infused to induce ICH in the region of CA1 of hippocampus of rats. The sham group took only saline infusion. For 7 days after the surgery, 4 testing groups had intraperitoneal injections of Paeoniae radix extract. The step-down inhibitory avoidance task, measurement of neurodegeneration degree in the CA1 region of the hippocampus, and detection of caspase-3 and newly generated cells in the dentate gyrus were done after animal sacrifice. Results : Rats receiving Paeoniae radix extract showed increased latency time in the inhibitory avoidance task. The extension of neuron-deprived areas in the CA1 region was significantly suppressed in the Paeonia treated groups. Also expressions of caspase-3 in the CA1 region and cortex were significantly inhibited in the Paeonia treated groups. The cell proliferation was evaluated by means of BrdU methods and proved to be decreased in the Paeonia treated groups. Conclusion : These results suggest that Paeoniae radix has potential to suppress short-tenn memory loss after devastating neurologic accidents. Also it was proved that Paeoniae radix has a neuroprotective effect and alleviates central nervous complications following intracerebral hemorrhage. Furthermore, it may imply that this medicinal plant can be widely used for vascular dementia and other neurodegenerative disorders.

• 한국통신학회논문지
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• 제23권9A호
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• pp.2289-2304
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• 1998

For the performance analysis and traffic control of ATM networks carrying video sequences, need an appropriate video traffic model. In this paper, we propose a new traffic model for MPEG compressed videos which are widely used for any type of video applications at th emoment. The proposed modeling scheme uses scene-based traffic characteristics and considers the correlation between frames of consecutiv GOPs. Using a simple scene detection algorithm, scene changes are modeled by state transitions and the number of GOPs of a scene state is modeled by a geometric distirbution. Frames of a scene stte are modeled by mean I, P, and B frame size. For more accurate traffic modeling, quantization errors (residual bits) that the state transition model using mean values has are compensated by autoregressive processes. We show that our model very well captures the traffic chracteristics of the original videos by performance analysis in terms of autocorrelation, histogram of frame bits genrated by the model, and cell loss rate in the ATM multiplexer with limited buffers. Our model is able to perrorm translations between levels (i.e., GOP, frame, and cell levels) and to estimate very accurately the stochastic characteristics of the original videos by each level.

• 한국통신학회논문지
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• 제24권7B호
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• pp.1322-1330
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• 1999

B-ISDN과 같은 초고속 네트워크에서 전송오류의 주요원인은 과잉밀집 상태에 있어서의 버퍼 오버플로우이며 이로 인해 셀 손실을 야기한다. 기존의 통신 프로토콜은 손실된 패킷이나 전송에러들을 다루기 위해 ARQ와 같이 오류회복을 위해 재전송 기법을 사용하고 있으나 이러한 ARQ 방법들은 재전송으로 인한 전송 지연시간이 매우 크기 때문에 초고속 네트워크에서는 적합하지 않다. 따라서 본 논문은 이러한 문제를 줄이기 위하여 B-ISDN에서 FEC를 이용한 셀손실 회복기법을 제안하였다. 제안된 기법은 새로운 순서번호(SN)인 SN*를 이용하여 연속적인 셀손실을 식별한다. SN*는 SN이외에 다른 두 개의 필드(ST, LI)를 조합하여 생성한 순서번호로 그 특성에 따라 가산적(additive) SN*와 승산적(multiplicative) SN*로 구분된다.이러한 연구결과로 FEC는 네트워크 노드상에 버퍼 오버플로우로 인한 셀손실이 발생한 경우에 유용하며 B-ISDN과 같은 초고속 통신망에서의 셀손실 회복에 효과적으로 사용할 수 있는 오류에 기법임을 보여주고 있다. 본 논문에서 제안된 효율적인 셀손실 회복기법은 향후 ATM 네트워크에서의 우선순위 제어, 과잉밀집 제어 등의 연\ulcorner에 효율적으로 사용될 수 있다.

• 한국통신학회논문지
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• 제24권9A호
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• pp.1372-1382
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• 1999

B-ISDN과 같은 초고속 네트워크에서 전송오류의 주요원인은 과잉밀집 상태에 있어서의 버퍼 오버플로우이며 이로 인해 셀손실을 야기한다. 기존의 통신 프로토콜은 손실된 패킷이나 전송에러들을 다루기 위해 ARQ와 같이 오류탐지와 재전송 기법을 사용하고 있으나 이러한 ARQ 방법들은 재전송으로 인한 전송 지연시간이 매우 크기 때문에 초고속 네트워크에서는 적합하지 않다. 따라서 본 논문은 이러한 문제를 줄이기 위하여 B-ISDN에서 Forward Error Correction(FEC)를 이용하여 셀손실 회복방법의 셀손실율을 수치적으로 분석하였다. FEC 기법은 Two-state Markov 모델인 셀손실 프로세스 모델을 기초한 성능평가에서 상당한 낮은 셀손실율을 나타내었으며 ATM 네트워크에 인터리빙의 적용은 버스티한 트래픽을 랜덤(random)하게 배열하게 함으로서 셀손실율을 개선할 수 있음을 보이고 있다. 이러한 요소들은 향후 오류제어 기법 설계시 고려해야 할 주요요소로 사용될 수 있다. 또한 IP-over-ATM 네트워크에서 신뢰성 있는 IP 패킷의 전달을 위하여 FEC 기법의 효과에 관한 성능을 분석하고 평가하였다. 본 성능평가의 결과로 FEC 기법은 IP-over-ATM 환경에\ulcorner 신뢰성이 있는 IP 전달을 위한 해결책을 제시한다.

• 대한바이러스학회지
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• 제28권4호
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• pp.359-368
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• 1998

Cytomegalovirus is the most common cause of life-threatening viral infection in HIV-infected patients. This study was done prospectively to investigate the incidence of CMV infection according to the decrease of CD4+ T cell count (CD4+) in Korean AIDS patients. Thirty-nine HIV-infected patients diagnosed before 1994 were followed for regular immunological monitoring. We have used urine shell vial method for the CMV detection from 1994 and have also checked clinical findings. Positive urine culture rate definitely depended on the CD4+ as follows; 45%, 22%, 17%, 11% and 0%, CD4+ <50, 50-100, 100-200, 200-500 and >500, respectively. Except culture positive 2 patients with CD4+ of $200{\sim}300/{\mu}l$, all eight culture positive patients with CD4+ less than $200/{\mu}l$ showed CMV related diseases on or before urine culture. But, we could not get a positive culture for a late AIDS patient with vision loss. With ganciclovir therapy, all culture results were at least negative just after or on late of first 14 days-ganciclovir infusion-course. These data suggest that the incidence of CMV disease in Korean AIDS patients is very high, and early diagnosis and treatment for CMV diseases is required for the prevention of life threatening results.

• Asian Pacific Journal of Cancer Prevention
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• 제13권12호
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• pp.6311-6318
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• 2012

Background: HER2/neu overexpression due to gene amplification is an important factor in breast cancer, modifying the sensitivity to anti-HER2 monoclonal antibody therapy. The clinical significance of HER2 expression in non small cell lung carcinoma (NSCLC) is currently under evaluation. The tumor suppressor gene PTEN negatively regulates the HER2/PI3K/Akt signalling pathway. The purpose of this study was to evaluate the role of simultaneous alteration in HER2 and PTEN protein expression in relation to biological behaviour of NSCLCs. Materials and Methods: Protein expression was determined by immunohistochemistry in sixty-one (n=61) NSCLC cases along with CISH for HER2 gene analysis and detection of chromosome 17 aneuploidy. Patients were followed-up for a period of 34 to 41 months after surgery. Results: HER2 overexpression (2+/3+score) was detected in 17 (27.9%) patients while loss of PTEN expression was observed in 24 (39.3%) cases, low expression in 29 (47.6%) and overexpression in 8 (13.1%). Simultaneous HER2 overexpression and PTEN low/loss of expression were correlated with metastasis (71.4% vs 36.2% p=0.03). Analysis in the subgroup of 22 patients of pTNM stage III with lymph node status N1 or N2 revealed that there was a relationship between the number of positive regional lymph node groups and simultaneous deregulation of the two genes (p=0.04). Multivariate analysis determined that HER2 overexpression was associated with an increasing risk of developing metastases (OR: 4.3; 95%CI: 1.2-15.9; p: 0.03) while PTEN overexpression was associated with lower risk (OR: 0.1; 95%CI: 0.1, 1.0; p: 0.05). Conclusions: Simultaneous HER2/PTEN deregulation is a significant genetic event that leads to a more aggressive phenotype of NSCLC.