480 research outputs found

    PROBABILITY-BASED SIMULATION OF 2-D VELOCITY DISTRIBUTION AND DISCHARGE ESTIMATION IN OPEN CHANNEL FLOW

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    A probability-based method is presented that can be used to simulate 2-D velocity distribution in rectangular open channels and to estimate the flow discharge. The method is based on Chiu's velocity distribution equation. A technique for estimating a parameter of 2-D velocity equation has been developed, by which the 2-D velocity distribution in rectangular open channels can be simulated by using one or several velocity samples, or even without using any velocity data. The present study also developed an efficient method of discharge estimation in rivers, which is applicable regardless of whether flow is steady or unsteady. It only requires a quick velocity sampling. The relation between the surface velocity and the vertical mean velocity has been studied. It can be used for developing a non-contact method of discharge measurement.Under the same framework of analysis, a new slope-area method has been developed to determine the flow discharge. It can reduce errors due to the uncertainties in Manning's n and the energy coefficient that exist in the widely-used slope-area method

    The antagonism between MCT-1 and p53 affects the tumorigenic outcomes

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    <p>Abstract</p> <p>Background</p> <p>MCT-1 oncoprotein accelerates p53 protein degradation via a proteosome pathway. Synergistic promotion of the xenograft tumorigenicity has been demonstrated in circumstance of p53 loss alongside MCT-1 overexpression. However, the molecular regulation between MCT-1 and p53 in tumor development remains ambiguous. We speculate that MCT-1 may counteract p53 through the diverse mechanisms that determine the tumorigenic outcomes.</p> <p>Results</p> <p>MCT-1 has now identified as a novel target gene of p53 transcriptional regulation. MCT-1 promoter region contains the response elements reactive with wild-type p53 but not mutant p53. Functional p53 suppresses MCT-1 promoter activity and MCT-1 mRNA stability. In a negative feedback regulation, constitutively expressed MCT-1 decreases p53 promoter function and p53 mRNA stability. The apoptotic events are also significantly prevented by oncogenic MCT-1 in a p53-dependent or a p53-independent fashion, according to the genotoxic mechanism. Moreover, oncogenic MCT-1 promotes the tumorigenicity in mice xenografts of p53-null and p53-positive lung cancer cells. In support of the tumor growth are irrepressible by p53 reactivation <it>in vivo</it>, the inhibitors of p53 (MDM2, Pirh2, and Cop1) are constantly stimulated by MCT-1 oncoprotein.</p> <p>Conclusions</p> <p>The oppositions between MCT-1 and p53 are firstly confirmed at multistage processes that include transcription control, mRNA metabolism, and protein expression. MCT-1 oncogenicity can overcome p53 function that persistently advances the tumor development.</p

    Enterovirus type 71 2A protease functions as a transcriptional activator in yeast

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    Enterovirus type 71 (EV71) 2A protease exhibited strong transcriptional activity in yeast cells. The transcriptional activity of 2A protease was independent of its protease activity. EV71 2A protease retained its transcriptional activity after truncation of 40 amino acids at the N-terminus but lost this activity after truncation of 60 amino acids at the N-terminus or deletion of 20 amino acids at the C-terminus. Thus, the acidic domain at the C-terminus of this protein is essential for its transcriptional activity. Indeed, deletion of amino acids from 146 to 149 (EAME) in this acidic domain lost the transcriptional activity of EV71 2A protein though still retained its protease activity. EV71 2A protease was detected both in the cytoplasm and nucleus using confocal microscopy analysis. Coxsackie virus B3 2A protease also exhibited transcriptional activity in yeast cells. As expected, an acidic domain in the C-terminus of Coxsackie virus B3 2A protease was also identified. Truncation of this acidic domain resulted in the loss of transcriptional activity. Interestingly, this acidic region of poliovirus 2A protease is critical for viral RNA replication. The transcriptional activity of the EV71 or Coxsackie virus B3 2A protease should play a role in viral replication and/or pathogenesis

    Two-Dimensional Fracture Mechanics Analysis Using a Single-Domain Boundary Element Method

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    This work calculates the stress intensity factors (SIFs) at the crack tips, predicts the crack initiation angles, and simulates the crack propagation path in the two-dimensional cracked anisotropic materials using the single-domain boundary element method (BEM) combined with maximum circumferential stress criterion. The BEM formulation, based on the relative displacements of the crack tip, is used to determine the mixed-mode SIFs and simulate the crack propagation behavior. Numerical examples of the application of the formulation for different crack inclination angles, crack lengths, degree of material anisotropy, and crack types are presented. Furthermore, the propagation path in Cracked Straight Through Brazilian Disc (CSTBD) specimen is numerically predicted and the results of numerical and experimental data compared with the actual laboratory observations. Good agreement is found between the two approaches. The proposed BEM formulation is therefore suitable to simulate the process of crack propagation. Additionally, the anisotropic rock slope failure initiated by the tensile crack can also be analyzed by the proposed crack propagation simulation technique

    Numerical modeling of unsaturated layered soil for rainfall-induced shallow landslides

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    In this paper, a pioneer study on numerical modeling of rainfall-induced shallow landslides in unsaturated layered soil using the variably saturated flow equation is presented. To model the shallow landslides, the infinite slope stability analysis coupled with the hydrological model with the consideration of the fluctuation of time-dependent pore water pressure and Gardner equation for soil water characteristic curve was developed. A linearization process for the nonlinear Richards equation to deal with groundwater flow in unsaturated layered soil is derived using the Gardner model. To solve one-dimensional flow in the unsaturated zone of layered soil profiles, flux conservation and the continuity of pressure potential at the interface between two consecutive layers are considered in the numerical discretization of the finite difference method. The validity of the proposed model is established in three numerical problems by comparing the results with the analytical and other numerical solutions. Application examples have also been conducted. Obtained results demonstrate that the fluctuation of pore water pressure in unsaturated layered soil dominates slope stability of landslides and the lowest factor of safety may occur at the interface between two consecutive layers. The findings observed in this study are a fundamental contribution to environmental protection engineering for landslides in areas with higher occurrence and vulnerability to extreme precipitation

    The Effects of Green Energy Production on Farmland: A Case Study in Yunlin County, Taiwan

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    Taiwan enacted the Act of Renewable Energy in the year 2009 which promotes energy safety, green economy, and a sustainable environment, and with that the government envisages a contribution of photovoltaic energy of up to 20% by the year 2025. In this study we look into the motivation and background of this energy policy, plans for implementation and associated challenges, and its actual consequences for farmland use and farmers. In addition, we take a look into the implementation of mixed-use farmland in which agricultural activity and photovoltaic installations are planned to coexist in order to increase land value and productivity. We furthermore report on some of our findings related to a field survey conducted in Taiwan’s corn chamber of Yunlin County which has been facing a number of socioeconomic challenges

    Gendered factors associated with preventive behaviors and mental health among Chinese adults during the COVID-19 pandemic home quarantine

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    The outbreak of the coronavirus disease in 2019 (COVID-19) has greatly impacted the life and mental health of many people globally. The objective of this study was to investigate the factors associated with preventive behaviors and mental health among Chinese adults during their home quarantine in the COVID-19 period. An online questionnaire survey was administered in March 2020. The study participants were adults aged between 18 and 70 years old from 31 provinces in China. Of the 3878 participants, 1314 reported moderate levels of anxiety, and the remaining participants reported moderate to severe levels of anxiety. Findings revealed that females aged between 18 and 30 years old who had higher educational qualifications, greater levels of preventive knowledge, trust in the government, and resided in urban and medium-risk areas (R2 = 0.100, F = 27.97, p < 0.001) were more likely to exhibit preventive behaviors. In contrast, a higher negative emotional response was generally seen in males who had low levels of preventive knowledge and behaviors, higher risk perception of infection, lower trust in the government, and unhealthy lifestyles (R2 = 0.127, F = 32.33, p < 0.001). In addition, the high-risk perception of infection was positively associated with high odds of anxiety (AOR = 1.17, 95% CI: 1.10–1.24), whereas a greater level of preventive knowledge (AOR = 0.36, 95% CI: 0.19–0.70) and behaviors (AOR = 0.69, 95% CI: 0.57–0.84), higher trust in the government’s COVID-19 pandemic mitigation measures (AOR = 0.77, 95% CI: 0.71–0.83), and a healthier lifestyle (AOR = 0.89, 95% CI: 0.79–0.99) were negatively associated with high odds of anxiety. Results showed that a lower level of anxiety and negative emotional response were associated with better preventive behaviors against COVID-19, which were influenced by preventive knowledge, risk perception, trust in the government’s COVID-19 pandemic mitigation measures, and healthy lifestyle. Findings in this study could help formulate health interventions for vulnerable groups related to gendered vulnerabilities in the COVID-19 environment to improve their mental health and preventive behaviors, especially during the period of a pandemic

    The Application of Borehole Hydrogeological Investigation for Assessing Landslide Susceptibility

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    On the basis of 49 borehole studies at the mid- and upper-stream of the Dajia and Jhuoshuei river basins, landslide occurrence was found to not only be related to subsurface geological composition and hydrogeological characteristics, but also to groundwater level dynamics, which have seldom been addressed in previous works. It is suggested that the interplay between hydrogeologic and landslide factors be given further consideration in future investigations. This would be a crucial step towards effective disaster prevention for mountainous regions in Taiwan.本研究主要係嘗試透過孔內水文地質調查結果,評估大甲溪與濁水溪流域地表下岩層的地質材料特性、水力特性、地下水與集水區山崩潛勢之關聯性。過去研究較少針對崩塌地進行現地水文地質調查與試驗,本研究根據49處試驗場址成果顯示,水文地質特性與山崩的潛勢、滑動深度,以及地下水位有一定程度之關聯性。本研究建議進行調查區域的水文地質特性,以及各促崩因子所造成的山崩的易損性,係各類型山崩災害分析與潛勢評估之重要的研究各題,亦可提供相關台灣災害防治之參考
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