• 제목/요약/키워드: Time-dependent degradation

검색결과 179건 처리시간 0.031초

The Causes of Deforestation and Loss of Genetic Resources in Bangladesh

  • Islam, Mohammad Saiful;Islam, Mohammad Jahidul;Ahmed, Sheikh Ali;Chun, Su-Kyoung;Chong, Song-Ho;Kim, Jong-In
    • 한국가구학회지
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    • 제18권4호
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    • pp.317-323
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    • 2007
  • Almost all the people, particularly the rural people are directly dependent on the continued productivity of natural resources, like water, soils, forests and fisheries. But the overuse by the extremely high population pressures has degraded the natural resources into severe widespread deforestation. The degradation of natural resources, particularly the plant resources has been a great concern for socio-economic and sustainable development of the country. The Forests in Bangladesh have been depleted and degraded in volume, area, and quantity, thus requiring urgent forest protection by identifying the causes of forest loss. There are so many causes of deforestation and loss of genetic resources such as; the timber industry, which, legal or not, are cutting too many trees; indigenous forest dwellers, having their own types of problems; migrants, who, because of problems in their places of origin, have decided to move to the forests and the government through its Forest Department which is not able or willing to implement suitable policies to regulate the cutting trees and to prevent illegal cutting. Because it is a time consuming task to mitigate the first and second sets of factors, we recommend involving forest dwellers in forestry practices as much as possible and taking necessary steps to alleviate the third and fourth sets and thereby reduce the rate of forest depletion. Accordingly, a number of strategies that should be adopted to halt the loss of remaining forest cover are discussed.

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복합견방사 및 그 제품개발에 관한 연구 (Studies on the compound spun silk and its fabrics)

  • 남중희;송기언
    • 한국잠사곤충학회지
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    • 제18권1호
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    • pp.27-39
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    • 1976
  • 복합견방사 및 복합견직물을 시작하여 다음의 결과를 얻었다. 1 정연제별 처리효과는 규산소다, 가성소다, 탄산소 및 비누의 순이다. 2. 가성소다 3% 액으로 정연할 경우는 견담백질의 과잉 용해로 진면제조가 불가하다. 3. 견의 정연효과는 처리시간보다 농도가 크다. 4. 정연제의 단독사용보다는 이중이상을 혼용하는 것이 진면품질을 향상시킬 수 있다. 5. 견수방사의 명주소리와 광택향상을 위하여서는 유기산의 혼용이 요구된다. 6. 심사에 의하여 복합수방사의 강도는 증가한다. 7. 복합수방사의 성도변동율은 8∼l2%이다. 8. 견과 데도롱직의 염색은 이욕법으로 처리하여야 한다. 9. 복합수방사 견직물의 수축율은 23%이다. 10. 복합수방사직물은 여자용 동복지로 복합생사 직물은 부라우스지로 사용 가능하다.

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Induction of ER Stress-Mediated Apoptosis by ${\alpha}$-Lipoic Acid in A549 Cell Lines

  • Kim, Jong-In;Cho, Sung-Rae;Lee, Chang-Min;Park, Eok-Sung;Kim, Ki-Nyun;Kim, Hyung-Chul;Lee, Hae-Young
    • Journal of Chest Surgery
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    • 제45권1호
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    • pp.1-10
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    • 2012
  • Background: ${\alpha}$-Lipoic acid (${\alpha}$-LA) has been studied as an anticancer agent as well as a therapeutic agent for diabetes and obesity. We performed this study to evaluate the anticancer effects and mechanisms of ${\alpha}$-LA in a lung cancer cell line, A549. Materials and Methods: ${\alpha}$-LA-induced apoptosis of A549 cells was detected by fluorescence-activated cell sorting analysis and a DNA fragmentation assay. Expression of apoptosis-related genes was analyzed by western blot and reverse transcription.polymerase chain reaction analyses. Results: ${\alpha}$-LA induced apoptosis and DNA fragmentation in A549 cells in a dose- and time-dependent manner. ${\alpha}$-LA increased caspase activity and the degradation of poly (ADP-ribose) polymerase. It induced expression of endoplasmic reticulum (ER) stress-related genes, such as glucose-regulated protein 78, C/EBP-homologous protein, and the short form of X-box binding protein-1, and decreased expression of the anti-apoptotic protein, X-linked inhibitor of apoptosis protein. Reactive oxygen species (ROS) production was induced by ${\alpha}$-LA, and the antioxidant N-acetyl-L-cysteine decreased the ${\alpha}$-LA-induced increase in expression of apoptosis and ER stress-related proteins. Conclusion: ${\alpha}$-LA induced ER stress-mediated apoptosis in A549 cells via ROS. ${\alpha}$-LA may therefore be clinically useful for treating lung cancer.

게이트 물질을 달리한 MOS소자의 플라즈마 피해에 대한 신뢰도 특성 분석 (The Evaluation for Reliability Characteristics of MOS Devices with Different Gate Materials by Plasma Etching Process)

  • 윤재석
    • 한국정보통신학회논문지
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    • 제4권2호
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    • pp.297-305
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    • 2000
  • 본 논문에서는 다양한 안테나 면적을 가지는 다결정실리콘(poly-Si) 및 폴리사이드(polycide) 게이트 물질을 게이트로 갖는 커패시터 및 n/p-MOS 트랜지스터를 사용하여 AAR(Antenna Area Ratio)의 크기에 따른 플라즈마 피해를 측정 및 분석하였다. 플라즈마 공정에 대한 신뢰도 특성을 조사하기 위해, MOS 소자의 게이트 물질을 달리하여 플라즈마 공정에 대한 초기 특성 및 F-N 스트레스와 hot carrier 스트레스 인가시의 n/p-MOSFET의 열화 특성을 측정한 결과 금속 AR에 의하여 플라즈마 공정의 영향을 받는 것으로 관찰되었다. 폴리사이드 게이트 구조가 다결정실리콘 게이트 구조보다 AAR에 따른 정전류 스트레스 인가시의 TDDB(Time Dependent Dielectric Breakdown)및 게이트 전압의 변화 등과 같은 신뢰성 특성에서 상당히 개선됨을 알 수 있었다. 이는 텅스텐 폴리사이드 형성 공정 중에 불소가 게이트 산화막에 함유되었기 때문인 것으로 설명할 수 있으며, 게이트 물질로 폴리사이드를 사용한 소자에서 플라즈마 영향을 줄일 수 있다는 사실이 차세대 MOS 소자의 게이트 박막으로 폴리사이드 게이트 박막을 활용할 수 있는 가능성을 확인하였다.

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Role of Retinoic Acid in Spontaneous Apoptosis of Human Neutrophils

  • Yang, Eun-Ju;Lee, Ji-Sook;Kim, Dong-Hee;Min, Bok-Kee;Hyun, Sung-Hee;Kim, In-Sik
    • 대한의생명과학회지
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    • 제13권4호
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    • pp.279-285
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    • 2007
  • Although retinoic acid has been known as either anti-inflammatory or pro-inflammatory molecule, depending on the cell type, its exact role in mature human neutrophils has not been fully explored. In this study, we investigate the effects of retinoic acid on neutrophil apoptosis and the associated mechanism and found that 9-cis retinoic acid (9CRA) significantly inhibits the spontaneous apoptosis of neutrophils. Its effect is increased by co-treatment with $TNF-\alpha$ (P<0.05). The 9CRA-induced inhibition is blocked by the following enzyme inhibitors: Ly 294002, phosphoinoside (PI)-3 kinase inhibitor, U73122, a phospholipase C (PLC) inhibitor, PP2, Src family protein inhibitor, SB202190, p38 MAPK inhibitor, and BAY-11-7085, NF-kB inhibitor. This study also demonstrates that all-trans retinoic acid suppresses spontaneous apoptosis, similar to the mechanism of inhibition exhibited by 9CRA. Phosphorylation of p38 MAPK decreases by 9CRA treatment. $Ik-B{\alpha}$ is degraded until 30 minutes after a time-dependent 9CRA treatment, but degradation can be inhibited by Ly 294002. These results indicate that 9CRA decreases p38 MAPK activation, induces NF-kB activation via PI-3 kinase, and also blocks cleavage of caspase 3. As these findings suggest, 9CRA has a molecular mechanism which may help pro-inflammatory response by blocking neutrophil apoptosis.

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매몰지 침출수의 경시변화에 따른 오염물질 분해특성 (Decomposition characteristics of pollutants by time dependent variation of livestock carcass leachate)

  • 김용준;강영렬;황동건;전태완;신선경
    • 분석과학
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    • 제30권6호
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    • pp.338-347
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    • 2017
  • 본 연구의 목적은 돼지와 소를 대상으로 우리나라 대표 토양인 사양질, 식양질, 사질의 토양에 따른 실험실 규모 가축 매몰지를 설치하여 3년동안 분해특성을 살펴보는 것이다. 그 결과 가축 매몰지역 환경조사지침에 따른 가축 매몰지 발굴금지기간인 3년을 기준으로 대부분 분해되는 것을 확인하였으며, 사체분해를 위해 중요인자로 온도, 수분, pH, 토성, 영양소, 매몰지 깊이 등 다양한 외부환경 요인이 적절히 유지되어야 할것으로 판단되었다. 또한 소의 경우가 돼지보다 빠르게 분해되었는데, 토양에 따른 분해속도를 확인한 결과 사질 > 식양질 > 사양질 순으로 분해가 이루어지는 것으로 판단되었다.

전립선 암세포에서 silymarin의 고사 유도 효과 및 기전 연구 (Apoptotic Effects and Mechanism Study of Silymarin in DU145 Cells)

  • 권강범;김은경;박성주;송호준;이영래;박병현;박진우;류도곤
    • 동의생리병리학회지
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    • 제19권6호
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    • pp.1552-1556
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    • 2005
  • Silymarin has been known to exert anti-tumoral activity in Korea. However, its molecular mechanism of action is not understood. In this study, we found that silymarin induced apoptosis in androgen-independent prostate cancer DU145 cells as confirmed by DNA fragmentation. Our data demonstrated that silymarin-induced apoptotic cell death was accompanied by activation of caspase-3 and subsequent cleavages of its substrates, poly(ADP-ribose) polymerase (PARP) in a time- and concentration-dependent manner. Also, silymarin-induced apoptotic mechanism of DU145 cells involved the induction of Par-4 protein expression. Taken together, these results suggest that silymarin induces the activation of caspase-3, degradation of PARP, increase of Par-4 expression, and eventually leads to apoptotic cell death.

네트워크 공격 탐지 성능향상을 위한 딥러닝을 이용한 트래픽 데이터 생성 연구 (Traffic Data Generation Technique for Improving Network Attack Detection Using Deep Learning)

  • 이우호;함재균;정현미;정기문
    • 한국융합학회논문지
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    • 제10권11호
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    • pp.1-7
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    • 2019
  • 네트워크 공격을 탐지하기 위하여 기계학습을 이용한 다양한 연구가 최근 급격히 증가하고 있다. 이러한 기계학습 방법은 많은 데이터에 의존적이며 연구를 위해 다양한 실험 데이터가 공개되어 사용되고 있다. 하지만 실험 데이터 및 실제 환경에서 수집되는 데이터는 class간의 수량이 불균형하다는 문제점을 가지고 있다. 본 연구에서는 기계 학습을 이용한 침입탐지시스템의 한계점 중 학습데이터의 class간 불균형으로 인한 분류 성능 저하를 해결하기 위한 방법을 제안한다. 이를 위해 네트워크 트래픽 데이터를 처리하고 seqGAN를 이용하여 부족한 데이터를 생성하였다. 제안된 방법은 NSL-KDD, UNSW-NB15 데이터 셋을 대상으로 Text-CNN을 이용하여 분류하는 테스트를 실행한 결과 정밀도가 향상되는 것을 확인할 수 있었다.

Efficient Elimination of Tetracycline by Ferrate (VI): Real Water Implications

  • Levia Lalthazuala;Lalhmunsiama Lalhmunsiama;Ngainunsiami Ngainunsiami;Diwakar Tiwari;Seung Mok Lee;Suk Soon Choi
    • 공업화학
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    • 제34권3호
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    • pp.318-325
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    • 2023
  • The detection of antibiotics in treated wastewater is a global concern as it enters water bodies and causes the development of antibiotic resistance genes in humans and marine life. The study specifically aims to explore the potential of ferrate (VI) in eliminating tetracycline (TCL). The degradation of TCL is optimized with parametric studies, viz., the effect of pH and concentration, which provide insights into TCL elimination. The increase in pH (from 7.0 to 10.0) favors the percentage removal of TCL; however, the increase in TCL concentrations from 0.02 to 0.3 mmol/L caused a decrease in percentage TCL removal from 97.4 to 29.1%, respectively, at pH 10.0. The time-dependent elimination of TCL using ferrate (VI) followed pseudosecond-order rate kinetics, and an apparent rate constant (kapp) was found at 1978.8 L2 /mol2 /min. Coexisting ions, i.e., NaNO3, Na2HPO4, NaCl, and oxalic acid, negligibly affect the oxidation of TCL by ferrate (VI). However, EDTA and glycine significantly inhibited the elimination of TCL using ferrate (VI). The mineralization of TCL using ferrate (VI) was favored at higher pH, and it increased from 18.57 to 32.52% when the solution pH increased from pH 7.0 to 10.0. Additionally, the real water samples containing a relatively high level of inorganic carbon spiked with TCL revealed that ferrate (VI) performance in the removal of TCL was unaffected, which further inferred the potential of ferrate (VI) in real implications.

Deep learning-based LSTM model for prediction of long-term piezoresistive sensing performance of cement-based sensors incorporating multi-walled carbon nanotube

  • Jang, Daeik;Bang, Jinho;Yoon, H.N.;Seo, Joonho;Jung, Jongwon;Jang, Jeong Gook;Yang, Beomjoo
    • Computers and Concrete
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    • 제30권5호
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    • pp.301-310
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    • 2022
  • Cement-based sensors have been widely used as structural health monitoring systems, however, their long-term sensing performance have not actively investigated. In this study, a deep learning-based methodology is adopted to predict the long-term piezoresistive properties of cement-based sensors. Samples with different multi-walled carbon nanotube contents (0.1, 0.3, and 0.5 wt.%) are fabricated, and piezoresistive tests are conducted over 10,000 loading cycles to obtain the training data. Time-dependent degradation is predicted using a modified long short-term memory (LSTM) model. The effects of different model variables including the amount of training data, number of epochs, and dropout ratio on the accuracy of predictions are analyzed. Finally, the effectiveness of the proposed approach is evaluated by comparing the predictions for long-term piezoresistive sensing performance with untrained experimental data. A sensitivity of 6% is experimentally examined in the sample containing 0.1 wt.% of MWCNTs, and predictions with accuracy up to 98% are found using the proposed LSTM model. Based on the experimental results, the proposed model is expected to be applied in the structural health monitoring systems to predict their long-term piezoresistice sensing performances during their service life.