67 research outputs found

    MXD3 regulation of DAOY cell proliferation dictated by time course of activation

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    BACKGROUND: MXD3 is a basic-helix-loop-helix-leucine-zipper transcription factor involved in cellular proliferation. In previous studies we demonstrated that knock-down of MXD3 in the human medulloblastoma cell line DAOY resulted in decreased proliferation. Surprisingly, overexpression of MXD3 in DAOY cells also decreased proliferation and increased cell death, suggesting that persistent expression of MXD3 triggers an apoptotic response, perhaps as a fail-safe mechanism. To investigate this apparent paradox in detail we developed a tamoxifen inducible system to analyze the temporal effects of MXD3 in the proliferation and transcriptional response of DAOY cells upon acute induction compared with long-term expression of MXD3. RESULTS: We find that acute induction of MXD3 initially promotes cell cycle progression as assessed by a transient increase in bromodeoxyuridine incorporation. However, persistent induction of MXD3 ultimately results in decreased proliferation based on cell counts. Finally, with microarray expression profiling and gene ontology analysis we identify several major pathways enriched in response to acute (immune response, apoptosis, cell cycle) versus persistent (cell adhesion) MXD3 activation. CONCLUSIONS: In this study, we demonstrate that acute MXD3 activation results in a transient increase in cell proliferation while persistent activation of MXD3 eventually results in an overall decrease in cell number, suggesting that the time course of MXD3 expression dictates the cellular outcome. Microarray expression profiling and gene ontology analysis indicate that MXD3 regulates distinct genes and pathways upon acute induction compared with persistent expression, suggesting that the cellular outcome is specified by changes in MXD3 transcriptional program in a time-dependent manner

    Effects of steel corrosion to BFRP Strengthened columns under eccentric loading

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    The experiment consists of twenty-four mid-scale rectangular RC columns (200x200x800mm) strengthening by BFRP sheets and research variables include: BFRP layer (0, 1, and 3 layers); eccentricity (25mm and 75mm); and 4 levels of steel corrosion. The results reveal that SEL (ratio of ultimate load of strengthened member to that of corresponding controlled member) is direct proportion with steel corrosion while SEV (ratio of ultimate vertical displacement of strengthened member to that of corresponding controlled member) is inverse proportion with steel corrosion; SEL slightly increases with the increase of BFRP layer and eccentricity; but SEV decreases noticeably with the increase of BFRP layer and eccentricity. In addition,the interaction between FRP sheets, stirrups, and longitudinal reinforcement in steel degraded BFRP strengthened columns is very strong.However, column design basing on current design manuals and codes as ACI 440.2R and CNR DT 200R1 has not mentioned this affect. Thus, the load capacity prediction of column being strengthened by BFRP sheets should include levels of steel corrosion for reality, reasonable, and integral of the design

    Effects of steel corrosion to BFRP Strengthened columns under eccentric loading

    Get PDF
    The experiment consists of twenty-four mid-scale rectangular RC columns (200x200x800mm) strengthening by BFRP sheets and research variables include: BFRP layer (0, 1, and 3 layers); eccentricity (25mm and 75mm); and 4 levels of steel corrosion. The results reveal that SEL (ratio of ultimate load of strengthened member to that of corresponding controlled member) is direct proportion with steel corrosion while SEV (ratio of ultimate vertical displacement of strengthened member to that of corresponding controlled member) is inverse proportion with steel corrosion; SEL slightly increases with the increase of BFRP layer and eccentricity; but SEV decreases noticeably with the increase of BFRP layer and eccentricity. In addition,the interaction between FRP sheets, stirrups, and longitudinal reinforcement in steel degraded BFRP strengthened columns is very strong.However, column design basing on current design manuals and codes as ACI 440.2R and CNR DT 200R1 has not mentioned this affect. Thus, the load capacity prediction of column being strengthened by BFRP sheets should include levels of steel corrosion for reality, reasonable, and integral of the design

    KHẢ NĂNG LƯU TRỮ CACBON CỦA THẢM CỎ BIỂN TẠI ĐẦM LĂNG CÔ, TỈNH THỪA THIÊN HUẾ

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    Seagrass beds play an essential role in mitigating climate change by absorbing CO2 from the atmosphere and converting carbon into biomass through photosynthesis. We used remote sensing and GIS technology with field survey data to establish the distribution and above-ground dry biomass maps of seagrass beds in 2021. A Landsat 8 OLI satellite image was used in the interpretation process. An above-ground dry biomass map was established by building the regression function between the above-ground dry biomass and the reflectance spectrum of the image bands. The overall accuracy and the Kappa coefficient of the classification process were 95.5% and 0.94. At Lang Co Lagoon, the seagrass bed area in 2021 was about 36.18 ha, distributed primarily in the area between Lang Co Town and the north of the lagoon; and scattered in the north of the lagoon, Hoi Can, Hoi Dua, and Hoi Mit. In addition, the total carbon stock of seagrasses in Lang Co Lagoon was estimated at 5.54 tons, equivalent to 20.32 tons of CO2, in which the contribution of Halodule uninervis accounted for 61% of the total carbon stock.Thảm cỏ biển đóng vai trò quan trọng trong việc giảm thiểu biến đổi khí hậu thông qua việc hấp thụ CO2 từ khí quyển và chuyển cacbon thành sinh khối nhờ quá trình quang hợp. Chúng tôi đã sử dụng công nghệ viễn thám và GIS, kết hợp với dữ liệu khảo sát thực địa, để thành lập bản đồ phân bố và sinh khối khô trên mặt đất của hệ sinh thái thảm cỏ biển tại Đầm Lăng Cô vào năm 2021. Một ảnh vệ tinh Landsat 8 OLI đã được sử dụng trong quá trình giải đoán. Một bản đồ sinh khối khô trên mặt đất được thành lập thông qua việc xây dựng hàm hồi quy giữa sinh khối khô trên mặt đất và phổ phản xạ của các kênh ảnh Landsat. Độ chính xác tổng thể và hệ số Kappa là 95,5% và 0,94. Tại Đầm Lăng Cô, diện tích thảm cỏ biển năm 2021 chiếm khoảng 36,18 ha, phân bố chủ yếu ở các khu vực giao giữa Thị trấn Lăng Cô và phía Bắc của đầm; rải rác tại phía Bắc của đầm, Hói Cạn, Hói Dừa và Hói Mít. Ngoài ra, tổng trữ lượng cacbon của cỏ biển ở Đầm Lăng Cô là 5,54 tấn cacbon, tương đương với 20,32 tấn CO2; trong đó, sự đóng góp của loài Halodule uninervis chiếm 61% tổng trữ lượng cacbon

    Global Norms in Domestic Politics: Environmental Norm Contestation in Cambodia’s Hydropower Sector

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    This paper studies environmental norm contestation in Cambodia's hydropower sector, exemplified by the Kamchay Dam. In Cambodia we can observe different discourses in relation to hydropower. These stem directly from a local contest over the path of Cambodia's development, but use global norms as reference points: one emphasizes environmental protection, using environmental impact assessment (EIA) as point of reference; and one emphasizes the utility of the clean development mechanism (CDM) to attract large-scale investment into the energy sector while downplaying the need for environmental protection. While EIA and CDM are complementary, key actors present them as contradictory. This produces a normative fragmentation of the field of environmental protection. The paper argues that the norm diffusion literature, by presenting norm conflicts as hierarchical local–global conflicts, has paid insufficient attention to the fact that local actors actively draw on global norms to justify domestic development policies. More emphasis on this phenomenon will lead to a better understanding of the role of global norms in domestic politics and will enhance our knowledge of how domestic development policies are contested

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

    Socializing One Health: an innovative strategy to investigate social and behavioral risks of emerging viral threats

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    In an effort to strengthen global capacity to prevent, detect, and control infectious diseases in animals and people, the United States Agency for International Development’s (USAID) Emerging Pandemic Threats (EPT) PREDICT project funded development of regional, national, and local One Health capacities for early disease detection, rapid response, disease control, and risk reduction. From the outset, the EPT approach was inclusive of social science research methods designed to understand the contexts and behaviors of communities living and working at human-animal-environment interfaces considered high-risk for virus emergence. Using qualitative and quantitative approaches, PREDICT behavioral research aimed to identify and assess a range of socio-cultural behaviors that could be influential in zoonotic disease emergence, amplification, and transmission. This broad approach to behavioral risk characterization enabled us to identify and characterize human activities that could be linked to the transmission dynamics of new and emerging viruses. This paper provides a discussion of implementation of a social science approach within a zoonotic surveillance framework. We conducted in-depth ethnographic interviews and focus groups to better understand the individual- and community-level knowledge, attitudes, and practices that potentially put participants at risk for zoonotic disease transmission from the animals they live and work with, across 6 interface domains. When we asked highly-exposed individuals (ie. bushmeat hunters, wildlife or guano farmers) about the risk they perceived in their occupational activities, most did not perceive it to be risky, whether because it was normalized by years (or generations) of doing such an activity, or due to lack of information about potential risks. Integrating the social sciences allows investigations of the specific human activities that are hypothesized to drive disease emergence, amplification, and transmission, in order to better substantiate behavioral disease drivers, along with the social dimensions of infection and transmission dynamics. Understanding these dynamics is critical to achieving health security--the protection from threats to health-- which requires investments in both collective and individual health security. Involving behavioral sciences into zoonotic disease surveillance allowed us to push toward fuller community integration and engagement and toward dialogue and implementation of recommendations for disease prevention and improved health security

    Alternative Splicing of MXD3 and Its Regulation of MXD3 Levels in Glioblastoma

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    The transcription factor MXD3 is an atypical member of the MYC/MAX/MXD transcriptional network and has been previously shown to be an important regulator of cell proliferation. MXD3 has been shown to be overexpressed and to be required for medulloblastoma and acute lymphoblastic leukemia cell proliferation. In this study we leveraged datasets from The Cancer Genome Atlas to examine MXD3 across several cancers. We find that MXD3 transcripts are significantly overexpressed in ~72% of the available datasets. The gene itself is not frequently altered, while the promoter appears to be hypomethylated. We examine the possibility that aberrant regulation of the MXD3 message is the cause of abnormal MXD3 expression across cancers. Specifically, we looked at MXD3 alternative splicing in glioblastoma multiforme (GBM) and find notable functional differences between the splice variants. The 3'UTR confers differential message stability. Furthermore, the different coding sequences lead to different protein stabilities and localizations. Altogether, these data extend our knowledge of MXD3 in the context of human cancers while characterizing a previously unstudied splice variant of MXD3
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