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Expression of p27Kip1, A Cell Cycle Repressor Protein with Dual Roles for Both Cancer Prevention and Promotion, Is Regulated Primarily at the Level of Unusual p27Kip1 mRNA—A Short Concept Proposal 被引量:2
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作者 Isao Eto 《American Journal of Molecular Biology》 2018年第3期186-193,共8页
The p27Kip1 is a cell cycle repressor protein that regulates primarily the cell cycle transition from G1 to S phase and hence the DNA replication is in the S phase and cell division in the M phase. Expression of p27Ki... The p27Kip1 is a cell cycle repressor protein that regulates primarily the cell cycle transition from G1 to S phase and hence the DNA replication is in the S phase and cell division in the M phase. Expression of p27Kip1 protein has dual roles for both cancer prevention and promotion. For example, numerous nutritional and chemopreventive anti-cancer agents specifically increase the expression of p27Kip1 protein without directly affecting the expression of any other cell cycle regulatory proteins. On the other hand, pro-cancer agents (like glucose, insulin and other growth factors frequently seen in obesity and/or diabetes) specifically decrease the expression of p27Kip1 protein without directly affecting the expression of any other cell cycle regulatory proteins. Unlike expression of any other cell cycle regulatory proteins, expression of p27Kip1 protein is very unusual. The mRNA of p27Kip1 has a very long and unusual 5’-untranslated region (from -575 to -1 in human). It appears that the 5’-untranslated region of p27Kip1 mRNA forms two alternative secondary structures. One increases the expression of p27Kip1 protein when anti-cancer agents are added and another decrease the expression of p27K1p1 when pro-cancer agents are added. For this short concept proposal, Dr. Albert Einstein’s “visualized thought experiments (German: Gedanken experiment)” were used as a fundamental tool for understanding how either anti- or pro-cancer agents bring the primary structure of the 5’-untranslated region of p27Kip1 mRNA into two alternative secondary structures, thereby either increasing or decreasing, respectively, the translation initiation of p27Kip1 protein. 展开更多
关键词 P27KIP1 Cell cycle Repressor Protein CANCER Prevention Anti-Cancer AGENTS CANCER PROMOTION Pro-Cancer AGENTS P27KIP1 MRNA 5-Prime-Untranslated Region Translation Initiation 5-Prime Cap Upstream Open Reading Frame Internal Ribosome Entry Site
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Spratlies Archipelago as the Australasian Tektite Impact Crater, Details of Formation &Richard Muller’s Dust Cloud Explanation for the Mid-Pleistocene Ice Age Cycle Transition 被引量:2
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作者 Hermann G. W. Burchard 《Open Journal of Geology》 2018年第1期1-8,共8页
Several significant events of a geological nature occurred approximately 800 ka before the present: (1) Australasian tektite fall (AA), (2) Brunhes-Matuyama geomagnetic reversal (BMR), (3) mid-Pleistocene changes in i... Several significant events of a geological nature occurred approximately 800 ka before the present: (1) Australasian tektite fall (AA), (2) Brunhes-Matuyama geomagnetic reversal (BMR), (3) mid-Pleistocene changes in ice age cycles. Add to these the undated fault system (4) in the South-West (SW) of the South China Sea (SCS). Here we offer a unified cause for all four of these in (5), an impact in the SCS of a large, massive cosmic object, likely a comet, obliquely coming from the SW at an extremely shallow angle, striking the Sunda shelf yet unexploded with the shock of its compressed air bow wave, and causing the continual shelf and slope to collapse, resulting in the fault system (4), then traveling almost tangentially to the surface, exploding at impact with the sea surface, ejecting the tektites (1), creating the formation underlying the later atolls of Spratlies Archipelago (6), Nansha Islands in Chinese, & causing the BMR (2). An explanation of event (3) was Richard Muller’s hypothesis of planet Earth passing through an interplanetary dust cloud periodically due to ecliptic precession. Here we hypothesize this cloud actually is a belt of Australasian tektites ejected into space at super-orbital velocities that Earth encounters about every 100 ka. 展开更多
关键词 Spratlies ARCHIPELAGO Cosmic Object Impact Crater Australasian TEKTITES Brunhes-Matuyama Geomagnetic Reversal RICHARD Muller Dust Cloud Hypothesis Mid-Pleistocene Ice Age cycle TRANSITION Google Earth High Resolution Update
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Analysis of Waste-Rock Transportation Process Performance in an Open-Pit Mine Based on Statistical Analysis of Cycle Times Data 被引量:1
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作者 Samwel Victor Manyele 《Engineering(科研)》 2017年第7期649-679,共31页
In this paper, the performance of a waste rock transportation process in an open pit mine was assessed by using cycle time data. A computerized truck-excavator dispatch system was used to record the cycle times. The p... In this paper, the performance of a waste rock transportation process in an open pit mine was assessed by using cycle time data. A computerized truck-excavator dispatch system was used to record the cycle times. The process was broken into seven steps (or components of the total cycle), durations of which were recorded for a period of 1 month, leading to N = 60,690 data points or dispatches. The open pit mine studied consisted of 12 waste types loaded by 14 excavators and hauled by 49 trucks (at a trucks-to-excavator ratio of 3.5:1) in 75 changing locations. The string-type data was coded using integers to allow a FORTRAN code to extract process performance parameters using statistical analysis. The study established a wide range of parameters including: the waste material generation rate (about 1.73 million t/month, 81% comprising waste rock), truck fill factor, f, total cycle time (Tct), production capacity, theoretical cycle time, non-productive cycle time Tnp, and cycle time performance ratio (CTPR), denoted as Tpr. The factors affecting the process performance include: truck model, excavator model, location (haul distance and road conditions) and material type. For a fixed material type and tonnage, the PDFs of the cycle time components were logarithmic in nature, capable of differentiating performance variations under different factors. It was concluded that the performance of the waste material transportation system in this mine was determined to be acceptable due to mean value of Tpr = 2.432 being closer to unity. Reduction measures were suggested to minimize the cycle time for the process bottlenecks determined from Pareto analysis (that is, full haul, empty haul and loading processes). 展开更多
关键词 Potentially Acid-Forming (PAF) ROCK Non-Acid FORMING (NAF) ROCK TRUCK Utilization TRUCK Fill-Factor QUEUING TIME Loading cycle TIME Full and Empty Haul Total cycle TIME Theoretical cycle TIME Non-Productive cycle TIME cycle TIME Performance Ratio
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Preliminary Design, Drive-Cycle Simulation and Energy Analysis of a Hybrid Transit Bus
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作者 Roberto Capata 《Journal of Energy and Power Engineering》 2019年第6期209-228,共20页
Modern metropolises are increasingly affected by air quality problems. Transportation is one of the largest sources of several pollutants emissions, such as nitrogen oxides (NOx) and carbon monoxide (CO). Today in the... Modern metropolises are increasingly affected by air quality problems. Transportation is one of the largest sources of several pollutants emissions, such as nitrogen oxides (NOx) and carbon monoxide (CO). Today in the EU, vehicles' emissions are strictly limited by Euro 6 norm-Euro VI for heavy-duty vehicles-which is periodically upgraded. To match such limits, manufacturers are forced in developing new technologies to perform new sustainable vehicles design strategies, such as EVs and HEVs. Present work's aim is to provide the design of series-hybrid urban transportation bus, equipped with a novel thermal power unit, namely a small gas turbine, to exploit its cleaner combustion process in comparison with an ICE. The control logic is described, while the main drivetrain components are chosen, and suitable models from suppliers are selected as well. Then, some simulations of the resulting vehicle are performed on opportune drive cycles, using Advisor, a free software based on Matlab-Simulink environment, published by US' National Renewable Energy Laboratory (NREL). Two different final configurations are environmentally and economically analysed, with the thermal power unit being respectively fuelled by compressed natural gas (CNG) and liquefied petroleum gas (LPG). Both satisfy the Euro VI norms, showing a substantial emission reduction (-89% and -43% in CO and THC releases respectively) in comparison to pollutants' threshold values. 展开更多
关键词 HEV GTHV heavy-duty bus ADVISOR MICROTURBINE (MT) gas turbine (GT) CNG LPG SIMULATION DRIVE cycle Euro VI WHTC emissions NOx CO THC sustainability pollution
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Investigation of Excavator Performance Factors in an Open-Pit Mine Using Loading Cycle Time
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作者 Samwel Victor Manyele 《Engineering(科研)》 2017年第7期599-624,共26页
This study presents the effect of excavator model, loading operation location, shift availability and truck-shovel combination on loading cycle time and productivity of an open-pit mine. The loading cycle time was use... This study presents the effect of excavator model, loading operation location, shift availability and truck-shovel combination on loading cycle time and productivity of an open-pit mine. The loading cycle time was used to assess the material loading system performance which is one of the key components of the total cycle time for material transportation in an open-pit mine. Loading is among the components of cycle time during which material is being handled. The data analyzed?was?collected from a computerized dispatch system at GGM from which 62,000 loading dispatches per month involving several shifts, 14 excavators and 49 trucks were loaded. About 4465 dispatches per excavator and 1276 dispatches per truck were assessed using loading cycle time data for each dispatch for a period of four months (between August and December). Under fixed tonnage loaded and waste type (33 t of non-acid forming waste rock),?it was observed that loading cycle time depends on excavator model, location and truck being loaded. Average cycle times, PDFS?and CDFS of loading cycle time series were used to identify differences in performance under different situations. It was concluded that shift availability for excavators, loading location, excavator model and truck-shovel combinations strongly affect the productivity during loading process in an open-pit mine. 展开更多
关键词 Potentially Acid-Forming (PAF) ROCK Non-Acid FORMING (NAF) ROCK TRUCK Utilization TRUCK Fill-Factor Queuing TIME LOADING cycle TIME Full and Empty Haul Total cycle TIME Theoretical cycle TIME Non-Productive cycle TIME cycle TIME Performance Ratio
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Life Cycle Assessment of CCA-Treated Wood Highway Guard Rail Posts in the US with Comparisons to Galvanized Steel Guard Rail Posts 被引量:1
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作者 Christopher A. Bolin Stephen T. Smith 《Journal of Transportation Technologies》 2013年第1期58-67,共10页
A cradle-to-grave life cycle assessment is done to identify the environmental impacts of chromated copper arsenate (CCA)-treated timber used for highway guard rail posts, to understand the processes that contribute to... A cradle-to-grave life cycle assessment is done to identify the environmental impacts of chromated copper arsenate (CCA)-treated timber used for highway guard rail posts, to understand the processes that contribute to the total impacts, and to determine how the impacts compare to the primary alternative product, galvanized steel posts. Guard rail posts are the supporting structures for highway guard rails. Transportation engineers, as well as public and regulatory interests, have increasing need to understand the environmental implications of guard rail post selection, in addition to factors such as costs and service performance. This study uses a life cycle inventory (LCI) to catalogue the input and output data from guard rail post manufacture, service life, and disposition, and a life cycle impact assessment (LCIA) to assess anthropogenic and net greenhouse gas (GHG), acidification, smog, ecotoxicity, and eutrophication potentially resulting from life cycle air emissions. Other indicators of interest also are tracked, such as fossil fuel and water use. Comparisons of guard rail post products are made at a functional unit of one post per year of service. This life cycle assessment (LCA) finds that the manufacture, use, and disposition of CCA-treated wood guard rails offers lower fossil fuel use and lower anthropogenic and net GHG emissions, acidification, smog potential, and ecotoxicity environmental impacts than impact indicator values for galvanized steel posts. Water use and eutrophication impact indicator values for CCA-treated guard rail posts are greater than impact indicator values for galvanized steel guard rail posts. 展开更多
关键词 Life cycle Assessment LCA LCI Environmental Impact Treated Wood Chromated Copper ARSENATE CCA Guard Rail Post Greenhouse Gas GHG Galvanized Steel
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Effect of cis-9,trans-11-conjugated linoleic acid on cell cycle of gastric adenocarcinoma cell line(SGC-7901) 被引量:26
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作者 Jia-Ren Liu Bai-Xiang Li Bing-Qing Chen Ying-ben Xue Yan-Mei Yang Yu-Mei Zheng,Department of Toxicological Health,Public Health College,Harbin Medical University,Harbin 150001,Heilongjiang Province,China Xiao-Hui Han ICU of Cardiological Surgery,The Second Hospital,Harbin Medical University,Harbin 150001,Heilongjiang Province,China Rui-Hai Liu,Food Science and Toxicology,Department of Food Science,Cornell University,Ithaca,NY 14853-7201,USA 《World Journal of Gastroenterology》 SCIE CAS CSCD 2002年第2期224-229,共6页
AIM: To determine the effect of cis -9, trans -11-conjugated linoleic acid (c9, t11-CLA) on the cell cycle of gastric cancer cells (SGC-7901) and its possible mechanism in inhibition cancer growth. METHODS: Using cell... AIM: To determine the effect of cis -9, trans -11-conjugated linoleic acid (c9, t11-CLA) on the cell cycle of gastric cancer cells (SGC-7901) and its possible mechanism in inhibition cancer growth. METHODS: Using cell culture and immunocytochemical techniques, we examined the cell growth, DNA synthesis, expression of PCNA, cyclin A, B(1), D(1), p16(ink4a) and p21(cip/waf1) of SGC-7901 cells which were treated with various c9, t11-CLA concentrations (25, 50, 100 and 200 micromol.L(-1))of c 9, t 11-CLA for 24 and 48h, with a negative control (0.1% ethane). RESULTS: The cell growth and DNA synthesis of SGC-7901 cells were inhibited by c9, t11-CLA.SGC-7901 cells. Eight day after treatment with various concentrations of c9, t11-CLA mentioned above, the inhibition rates were 5.92%, 20.15%, 75.61% and 82.44%, respectively and inhibitory effect of c9, t11-CLA on DNA synthesis (except for 25 micromol.L, 24h) showed significantly less (3)H-TdR incorporation than that in the negative controls (P【0.05 and P【0.01). Immunocytochemical staining demonstrated that SGC-7901 cells preincubated in media supplemented with different c9, t11-CLA concentrations at various times significantly decreased the expressions of PCNA (the expression rates were 7.2-3.0%, 24h and 9.1-0.9% at 48h, respectively), Cyclin A (11.0-2.3%, 24h and 8.5-0.5%,48h), B(1) (4.8-1.8% at 24h and 5.5-0.6% at 48h)and D(1) (3.6-1.4% at 24h and 3.7%-0 at 48h) as compared with those in the negative controls(the expressions of PCNA, Cyclin A, B(1) and D(1) were 6.5% at 24h and 9.0% at 48h, 4.2% at 24h and 5.1% at 48h, 9.5% at 24h and 6.0% at 48h,respectively)(P【0.01), whereas the expressions of P16(ink4a) and P21(cip/waf1), cyclin-dependent kinases inhibitors(CDKI), were increased. CONCLUSION: The cell growth and proliferation of SGC-7901 cell is inhibited by c9, t11-CLA via blocking the cell cycle, with reduced expressions of cyclin A,B(1) and D(1) and enhanced expressions of CDKI(P16(ink4a) and p21(cip/waf1)). 展开更多
关键词 Linoleic Acids Conjugated ADENOCARCINOMA Animals Cell cycle Cell Division Cyclin A Cyclin B Cyclin D1 Cyclin-Dependent Kinase Inhibitor p16 Cyclin-Dependent Kinase Inhibitor p21 CYCLINS Enzyme Inhibitors Humans Immunohistochemistry Linoleic Acids Proliferating Cell Nuclear Antigen Research Support Non-U.S. Gov't Stomach Neoplasms Tumor Cells Cultured
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Cdk5 and aberrant cell cycle activation at the core of neurodegeneration 被引量:3
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作者 Raquel Requejo-Aguilar 《Neural Regeneration Research》 SCIE CAS CSCD 2023年第6期1186-1190,共5页
Neurodegenerative diseases are caused by the progressive loss of specific neurons.The exact mechanisms of action of these diseases are unknown,and many studies have focused on pathways related to abnormal accumulation... Neurodegenerative diseases are caused by the progressive loss of specific neurons.The exact mechanisms of action of these diseases are unknown,and many studies have focused on pathways related to abnormal accumulation and processing of proteins,mitochondrial dysfunction,and oxidative stress leading to apoptotic death.However,a growing body of evidence indicates that aberrant cell cycle re-entry plays a major role in the pathogenesis of neurodegeneration.The activation of the cell cycle in mature neurons could be promoted by several signaling mechanisms,including c-Jun N-terminal kinases,p38 mitogen-activated protein kinases,and mitogen-activated protein kinase/extracellular signal-regulated kinase cascades;post-translational modifications such as Tau-phosphorylation;and DNA damage response.In all these events,implicated Cdk5,a proline-directed serine/threonine protein kinase,seems to be responsible for several cellular processes in neurons including axon growth,neurotransmission,synaptic plasticity,neuronal migration,and maintenance of neuronal survival.However,under pathological conditions,Cdk5 dysregulation may lead to cell cycle re-entry in post-mitotic neurons.Thus,Cdk5 hyperactivation,by its physiologic activator p25,hyper-phosphorylates downstream substrates related to neurodegenerative diseases.This review summarizes factors such as oxidative stress,DNA damage response,signaling pathway disturbance,and Ubiquitin proteasome malfunction contributing to cell cycle re-entry in post-mitotic neurons.It also describes how all these factors are linked to a greater or lesser extent with Cdk5.Thus,it offers a global vision of the function of cell cycle-related proteins in mature neurons with a focus on Cdk5 and how this protein contributes to the development of Alzheimer’s disease,Parkinson’s disease,amyotrophic lateral sclerosis,and Huntington’s disease by cell cycle activation. 展开更多
关键词 Alzheimer´s disease amyotrophic lateral sclerosis apoptosis CDK5 cell cycle Huntington´s disease NEURODEGENERATION neuron oxidative stress Parkinson´s disease signaling Tau phosphorylation
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有向图上基于层次树索引的最大cycle truss社区搜索
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作者 宗传玉 张纯鹤 夏秀峰 《计算机应用》 CSCD 北大核心 2024年第1期190-198,共9页
社区搜索旨在从信息网络中找出包含用户查询顶点的高内聚连通子图,cycle truss是一种基于cycle三角形的社区搜索模型,而现有的基于索引的cycle truss社区搜索方法存在索引空间大、搜索效率低、社区内聚性低的缺点。为了解决这一问题,提... 社区搜索旨在从信息网络中找出包含用户查询顶点的高内聚连通子图,cycle truss是一种基于cycle三角形的社区搜索模型,而现有的基于索引的cycle truss社区搜索方法存在索引空间大、搜索效率低、社区内聚性低的缺点。为了解决这一问题,提出一种基于层次树索引的最大cycle truss社区搜索方法。首先,提出了k-cycle truss分解算法,并引入了两个重要的概念:cycle三角连通与k-层次等价。基于k-层次等价设计了层次树索引TreeCIndex与表结构索引SuperTable,在此基础上,并基于这两个新的索引,提出了两个高效的cycle truss社区搜索算法。在4个真实数据集上与已有的基于TrussIndex与EquiTruss的社区搜索算法进行了比较,实验结果表明,TreeCIndex与SuperTable比TrussIndex与EquiTruss节省至少41.5%的空间,索引构建的时间节省8.2%至98.3%,且搜索最大cycle truss社区的效率分别高出了一个和两个数量级。 展开更多
关键词 cycle truss cycle三角形
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A Review on Technologies for the Use of CO2 as a Working Fluid in Refrigeration and Power Cycles
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作者 Orelien T. Boupda Hyacinthe D. Tessemo +3 位作者 Isidore B. Nkounda Fongang Francklin G. Nyami Frederic Lontsi Thomas Djiako 《Energy and Power Engineering》 2024年第6期217-256,共40页
The use of carbon dioxide as a working fluid has been the subject of extensive studies in recent years, particularly in the field of refrigeration where it is at the heart of research to replace CFC and HCFC. Its ther... The use of carbon dioxide as a working fluid has been the subject of extensive studies in recent years, particularly in the field of refrigeration where it is at the heart of research to replace CFC and HCFC. Its thermodynamic properties make it a fluid of choice in the efficient use of energy at low and medium temperatures in engine cycles. However, the performance of transcritical CO2 cycles weakens under high temperature and pressure conditions, especially in refrigeration systems;On the other hand, this disadvantage becomes rather interesting in engine cycles where CO2 can be used as an alternative to the organic working fluid in small and medium-sized electrical systems for low quality or waste heat sources. In order to improve the performance of systems operating with CO2 in the field of refrigeration and electricity production, research has made it possible to develop several concepts, of which this article deals with a review of the state of the art, followed by analyzes in-depth and critical of the various developments to the most recent modifications in these fields. Detailed discussions on the performance and technical characteristics of the different evolutions are also highlighted as well as the factors affecting the overall performance of the systems studied. Finally, perspectives on the future development of the use of CO2 in these different cycles are presented. 展开更多
关键词 Refrigeration cycle Power cycle System Performance Transcritical CO2 cycles Working Fluid
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Observed Solar Cycle Variation of the Stratospheric QBO Generated in the Mesosphere and Amplified by Upward Propagating Waves
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作者 Hans G. Mayr Frank T. Huang Jae N. Lee 《Atmospheric and Climate Sciences》 2018年第1期63-83,共21页
With an analysis of zonal wind observations over 40 years, Salby and Callaghan [1] showed that the Quasi-biennial Oscillation (QBO) at 20 km is modulated by 11-year solar cycle (SC) variations from about 12 to 20 m/s ... With an analysis of zonal wind observations over 40 years, Salby and Callaghan [1] showed that the Quasi-biennial Oscillation (QBO) at 20 km is modulated by 11-year solar cycle (SC) variations from about 12 to 20 m/s (Figure 2). The observations are reproduced qualitatively in a study with the 3D Numerical Spectral Model, which shows that the SC effect of the stratospheric QBO is produced by dynamical downward coupling originating in the mesosphere. In this modeling study, the SC period is taken to be 10 years, and a realistic heat source is applied varying exponentially with altitude: 0.2%, surface;2%, 50 km;20%, 100 km and above. The numerical results show that the variable solar radiation in the mesosphere around 65 km generates a hemispheric symmetric Equatorial Annual Oscillation (EAO), which is modulated by relatively large SC variations. Under the influence of wave mean flow interactions, the EAO propagates into the lower atmosphere and is the dynamical source or pacemaker for the large SC modulation of the QBO. The numerical results show that the upward propagating small-scale gravity waves from the troposphere amplify the SC modulations of the QBO and EAO in the stratosphere, part of the SC mechanism. The zonal winds of the equatorial QBO and EAO produce through the meridional circulation measurable SC variations in the temperature of the stratosphere and troposphere at high latitudes. Analysis of NCEP temperature and zonal wind data (1958 to 2006) provides observational evidence of the EAO with SC variations around 11 years. 展开更多
关键词 Quasi-Biennial OSCILLATION (QBO) OBSERVED Solar cycle Variations Modeling Study Equatorial Annual OSCILLATION (EAO) Dynamical DOWNWARD Coupling Wave Mean-Flow INTERACTIONS Non-Linear INTERACTIONS
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Dual‑Atom Nanozyme Eye Drops Attenuate Inflammation and Break the Vicious Cycle in Dry Eye Disease
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作者 Dandan Chu Mengyang Zhao +8 位作者 Shisong Rong Wonho Jhe Xiaolu Cai Yi Xiao Wei Zhang Xingchen Geng Zhanrong Li Xingcai Zhang Jingguo Li 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第6期439-457,共19页
Dry eye disease(DED)is a major ocular pathology worldwide,causing serious ocular discomfort and even visual impairment.The incidence of DED is gradually increasing with the highfrequency use of electronic products.Alt... Dry eye disease(DED)is a major ocular pathology worldwide,causing serious ocular discomfort and even visual impairment.The incidence of DED is gradually increasing with the highfrequency use of electronic products.Although inflammation is core cause of the DED vicious cycle,reactive oxygen species(ROS)play a pivotal role in the vicious cycle by regulating inflammation from upstream.Therefore,current therapies merely targeting inflammation show the failure of DED treatment.Here,a novel dual-atom nanozymes(DAN)-based eye drops are developed.The antioxidative DAN is successfully prepared by embedding Fe and Mn bimetallic single-atoms in N-doped carbon material and modifying it with a hydrophilic polymer.The in vitro and in vivo results demonstrate the DAN is endowed with superior biological activity in scavenging excessive ROS,inhibiting NLRP3 inflammasome activation,decreasing proinflammatory cytokines expression,and suppressing cell apoptosis.Consequently,the DAN effectively alleviate ocular inflammation,promote corneal epithelial repair,recover goblet cell density and tear secretion,thus breaking the DED vicious cycle.Our findings open an avenue to make the DAN as an intervention form to DED and ROSmediated inflammatory diseases. 展开更多
关键词 Dry eye disease DAN Dual-atom nanozyme Vicious cycle NLRP3 inflammasome NANOMEDICINE
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Effects of dry-wet cycles on the mechanical properties of sandstone with unloading-induced damage
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作者 NAN Gan ZHANG Jiaming +2 位作者 LUO Yi WANG Xinlong HU Zhongyi 《Journal of Mountain Science》 SCIE CSCD 2024年第10期3474-3486,共13页
Sandstone is the fundamental material in various engineering and construction projects.However,the mechanical integrity of sandstone can be compromised by initial unloading damage resulting from activities such as eng... Sandstone is the fundamental material in various engineering and construction projects.However,the mechanical integrity of sandstone can be compromised by initial unloading damage resulting from activities such as engineering excavations.Furthermore,this degradation is further exacerbated under periodic dry-wet environmental conditions.This study investigated the effects of dry-wet cycles and unloading on the mechanical properties of jointed fine sandstone using uniaxial and triaxial compression tests.These tests were performed on rock samples subjected to varying unloading degrees and different numbers of dry-wet cycles.The results demonstrate that with an increase in the unloading degree from 0%to 70%,there is a corresponding decrease in peak stress ranging from 10%to 33%.Additionally,the cohesion exhibits a reduction of approximately 20%to 25%,while the internal friction angle experiences a decline of about 3.5%to 6%.These findings emphasize a significant unloading effect.Moreover,the degree of peak stress degradation in unloading jointed fine sandstone diminishes with an increase in confining pressure,suggesting that confining pressure mitigates the deterioration caused by dry-wet cycles.Additionally,as the number of dry-wet cycles increases,there is a notable decline in the mechanical properties of the sandstone,evidencing significant dry-wet degradation.Utilizing the Drucker Prager criterion,this study establishes a strength criterion and fracture criterion,denoted asσ1(m,n)and,to quantify the combined impacts of dry-wet cycles and unloading on jointed fine sandstone,which provides a comprehensive understanding of its mechanical behavior under such conditions. 展开更多
关键词 UNLOADING Dry-wet cycle Jointed fine sandstone Strength criterion fracture criterion Mechanical properties
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Hydrangea serrata extract exerts tumor inhibitory activity against hepatocellular carcinoma HepG2 cells via inducing p27/CDK2-mediated cell cycle arrest and apoptosis
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作者 Ye-eun Kim Jeonghye Hwang Ki-Young Kim 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2024年第2期65-72,I0002-I0005,共12页
Objective:To examine the inhibitory effect of Hydrangea serrata extract against hepatocellular carcinoma HepG2 cells and its underlying mechanisms.Methods:The effects of Hydrangea serrata extract on growth inhibition ... Objective:To examine the inhibitory effect of Hydrangea serrata extract against hepatocellular carcinoma HepG2 cells and its underlying mechanisms.Methods:The effects of Hydrangea serrata extract on growth inhibition of tumor cells and spheroids were assessed using MTT and 3D culture assays.Quantitative real-time PCR and Western blot analyses were employed to investigate the changes in mRNA and protein expression levels of molecules related to cell cycle and apoptosis.Results:Hydrangea serrata extract effectively inhibited the growth of both tumor cells and spheroids.The extract also significantly upregulated p27 mRNA expression and downregulated CDK2 mRNA expression,leading to cell cycle arrest.Moreover,increased BAX/Bcl-2 ratio as well as caspase-9 and-3 were observed after treatment with Hydrangea serrata extract,indicating the induction of tumor cell apoptosis.Conclusions:Hydrangea serrata extract has the potential to alleviate tumors by effectively modulating cell-cycle-related gene expressions and inducing apoptosis,thereby inhibiting tumor growth. 展开更多
关键词 Hydrangea serrata Hepatocellular carcinoma Liver cancer Anticancer Cell cycle arrest APOPTOSIS
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Antitumor Effect of Apcin on Endometrial Carcinoma via p21-Mediated Cell Cycle Arrest and Apoptosis
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作者 Ke NI Zi-li LI +1 位作者 Zhi-yong HU Li HONG 《Current Medical Science》 SCIE CAS 2024年第3期623-632,共10页
Objective Endometrial carcinoma(EC)is a prevalent gynecological malignancy characterized by increasing incidence and mortality rates.This underscores the critical need for novel therapeutic targets.One such potential ... Objective Endometrial carcinoma(EC)is a prevalent gynecological malignancy characterized by increasing incidence and mortality rates.This underscores the critical need for novel therapeutic targets.One such potential target is cell division cycle 20(CDC20),which has been implicated in oncogenesis.This study investigated the effect of the CDC20 inhibitor Apcin on EC and elucidated the underlying mechanism involved.Methods The effects of Apcin on EC cell proliferation,apoptosis,and the cell cycle were evaluated using CCK8 assays and flow cytometry.RNA sequencing(RNA-seq)was subsequently conducted to explore the underlying molecular mechanism,and Western blotting and coimmunoprecipitation were subsequently performed to validate the results.Animal studies were performed to evaluate the antitumor effects in vivo.Bioinformatics analysis was also conducted to identify CDC20 as a potential therapeutic target in EC.Results Treatment with Apcin inhibited proliferation and induced apoptosis in EC cells,resulting in cell cycle arrest.Pathways associated with apoptosis and the cell cycle were activated following treatment with Apcin.Notably,Apcin treatment led to the upregulation of the cell cycle regulator p21,which was verified to interact with CDC20 and consequently decrease the expression of downstream cyclins in EC cells.In vivo experiments confirmed that Apcin treatment significantly impeded tumor growth.Higher CDC20 expression was observed in EC tissue than in nonmalignant tissue,and increased CDC20 expression in EC patients was associated with shorter overall survival and progress free interval.Conclusion CDC20 is a novel molecular target in EC,and Apcin could be developed as a candidate antitumor drug for EC treatment. 展开更多
关键词 endometrial carcinoma CDC20 APOPTOSIS cell cycle arrest P21 BBC3
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Very High Cycle Fatigue Behaviors and Surface Crack Growth Mechanism of Hydrogen-Embrittled AISI 304 Stainless Steels
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作者 Seung-Hoon Nahm Hyun-Bo Shim +1 位作者 Un-Bong Baek Chang-Min Suh 《Materials Sciences and Applications》 2018年第4期393-411,共19页
The influence of hydrogen embrittlement on the fatigue behaviors of AISI 304 stainless steel is investigated. The fatigue endurance limits of the untreated and hydrogen-embrittled materials were almost the same at 400... The influence of hydrogen embrittlement on the fatigue behaviors of AISI 304 stainless steel is investigated. The fatigue endurance limits of the untreated and hydrogen-embrittled materials were almost the same at 400 MPa, and hydrogen embrittlement had little influence even though the sample contained about 8.1 times more hydrogen. Thus, the sensitivity of hydrogen gas in this material is very low. A surface crack initiation, growth, coalescence, and micro ridge model is proposed in this study. Slip line formation?&rArr;microcrack formation?&rArr;increases in the crack width, and blunting of the crack tip as it grows?&rArr;formation of many slip lines because of deformation in the shear direction?&rArr;growth of the crack in the shear direction, forming micro ridges, coalescence with adjacent cracks &rArr;?continuous initiation, growth, coalescence, and ridge formation of surface cracks and specimen breakage. 展开更多
关键词 Hydrogen-Embrittled FATIGUE BEHAVIORS SURFACE Crack Initiation Growth COALESCENCE Micro Ridge Formation VHCF (Very High cycle Fatigue) Fracture SURFACE Analysis
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Effect of dry-wet cycles on dynamic properties and microstructures of sandstone:Experiments and modelling
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作者 Hai Pu Qingyu Yi +3 位作者 Andrey P.Jivkov Zhengfu Bian Weiqiang Chen Jiangyu Wu 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第5期655-679,共25页
Underground pumped storage power plant(UPSP)is an innovative concept for space recycling of abandoned mines.Its realization requires better understanding of the dynamic performance and durability of reservoir rock.Thi... Underground pumped storage power plant(UPSP)is an innovative concept for space recycling of abandoned mines.Its realization requires better understanding of the dynamic performance and durability of reservoir rock.This paper conducted ultrasonic detection,split Hopkinson pressure bar(SHPB)impact,mercury intrusion porosimetry(MIP),and backscatter electron observation(BSE)tests to investigate the dynamical behaviour and microstructure of sandstone with cyclical dry-wet damage.A coupling FEM-DEM model was constructed for reappearing mesoscopic structure damage.The results show that dry-wet cycles decrease the dynamic compressive strength(DCS)with a maximum reduction of 39.40%,the elastic limit strength is reduced from 41.75 to 25.62 MPa.The sieved fragments obtain the highest crack growth rate during the 23rd dry-wet cycle with a predictable life of 25 cycles for each rock particle.The pore fractal features of the macropores and micro-meso pores show great differences between the early and late cycles,which verifies the computational statistics analysis of particle deterioration.The numerical results show that the failure patterns are governed by the strain in pre-peak stage and the shear cracks are dominant.The dry-wet cycles reduce the energy transfer efficiency and lead to the discretization of force chain and crack fields. 展开更多
关键词 Underground pumped storage power plant Dry-wet cycles Split Hopkinson pressure bar Macro and micro properties FEM-DEM coupling model Damage characterization
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Changes in calcium accumulation and utilization efficiency and their impact on recycling,immobilization,and export across the oil palm cycle
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作者 Ismael de Jesus Matos Viégas Luma Castro de Souza +4 位作者 Eric Victor de Oliveira Ferreira Milton Garcia Costa Glauco André dos Santos Nogueira Vitor Resende do Nascimento Candido Ferreira de Oliveira Neto 《Oil Crop Science》 CSCD 2024年第3期143-150,共8页
Effective calcium(Ca)management is crucial for optimizing oil palm cultivation and enhancing crop yield.This study aimed to gain insights into the dynamics of Ca concentration,accumulation,exportation,immobilization,a... Effective calcium(Ca)management is crucial for optimizing oil palm cultivation and enhancing crop yield.This study aimed to gain insights into the dynamics of Ca concentration,accumulation,exportation,immobilization,and recycling in various oil palm organs relative to plant age.The experiment was conducted at the Agropalma enterprise site in the northeastern region of Para State,Brazil,evaluating seven plant age treatments:2,3,4,5,6,7,and 8 years old.Employing a completely randomized design with four replications.The results demonstrated an age-related increase in Ca concentration in petioles,rachis,arrows,male inflorescences,peduncles,and fruits.Furthermore,Ca accumulation exhibited an upward trend in all organs with progressing plant age.Notably,the study revealed an enhanced Ca use efficiency across all plant organs in correlation with the age of oil palm cultivation.These findings underscore the dynamic nutritional demands of oil palm,influencing Ca immobilization,cycling,and export throughout its developmental stages. 展开更多
关键词 Elaeis guineensis Jacq Ca cycling Ca export Ca immobilization Ca use efficiency Plant nutrition AMAZON
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Long non-coding RNA GAS5 promotes PC12 cells differentiation into Tuj1-positive neuron-like cells and induces cell cycle arrest 被引量:5
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作者 He-Yan Zhao Sheng-Tong Zhang +7 位作者 Xiang Cheng Hao-Ming Li Lei Zhang Hui He Jian-Bing Qin Wei-Ye Zhang Yan Sun Guo-Hua Jin 《Neural Regeneration Research》 SCIE CAS CSCD 2019年第12期2118-2125,共8页
Growth arrest-specific 5 (GAS5) is an anti-oncogene that has been extensively studied in tumors. However, research on GAS5 in the context of nervous system disease is rare at present. This study aimed to investigate t... Growth arrest-specific 5 (GAS5) is an anti-oncogene that has been extensively studied in tumors. However, research on GAS5 in the context of nervous system disease is rare at present. This study aimed to investigate the role of the long non-coding RNA GAS5 in rat pheochromocytoma cells (PC12 cells). GAS5-overexpressing lentivirus was transfected into PC12 cells, and expression levels of GAS5 and C-myc were detected by real-time PCR. Ratios of cells in S phase were detected by 5-ethynyl-2′-deoxyuridine. Immunohistochemical staining was used to detect the immunoreactivity of neuron microtubule markers Tuj1, doublecortin, and microtubule-associated protein 2. Apoptosis was detected by flow cytometry, while expression of acetylcholine in cells was detected by western blot assay. We found that GAS5 can promote PC12 cells to differentiate into Tuj1-positive neuron-like cells with longer processes. In addition, cell proliferation and cell cycle were significantly suppressed by GAS5, whereas it had no effect on apoptosis of PC12 cells. Our results indicate that GAS5 could increase the expression of choline acetyltransferase and acetylcholine release. Thus, we speculate that GAS5 is beneficial to the recovery of neurons and the cholinergic nervous system. 展开更多
关键词 nerve REGENERATION growth arrest-specific 5 PC12 CELL neuron proliferation CELL cycle CHOLINE ACETYLTRANSFERASE ACETYLCHOLINE Alzheimer's disease neural REGENERATION
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Medicated Serum of Qishen Yiqi Pill Affect Vascular Smooth Muscle Cell Proliferation,Cell Cycle,Cyclin D1 and CDK4 Mechanism Research
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作者 Zhang Xinying Gu Xufang +1 位作者 Xu Qiang Wang Baohe 《世界中医药》 CAS 2017年第A01期103-104,106,共3页
Observation of stilbene dropping pill and yiqi drug-containing serum influence mechanism of vascular smooth muscle proliferation, cell cycle and Cyclin D1 and CDK4Choose male SD rats were randomly divided into 2 gr... Observation of stilbene dropping pill and yiqi drug-containing serum influence mechanism of vascular smooth muscle proliferation, cell cycle and Cyclin D1 and CDK4Choose male SD rats were randomly divided into 2 groups, lavage qishen yiqi pill and the gastric saline group,extract the drug-containing serum and normal serum;To set the two groups of serum respectively different concentrations,concentration in different time by CCK8 detection effects on vascular smooth muscle cell proliferation, select best concentration and action time.Flow cytometry instrument and high-throughput screening detect serum medicated effect on vascular smooth muscle cell cycle;Western blot detect the drug-containing serum of cell cycle protein Cyclin D1 and CDK4 expression.Result is 5%, 10% medicated serum inhibits cell proliferation significantly higher than the normal serum concentrations of same within 24 h, 48 h.G1 phase cells 5% medicated serum group was obviously higher than that of 5% in normal group (P<005), serum and cell proliferation index significantly less than 5% normal serum group (P<005),At the same time, Cyclin D1 and CDK4 expression significantly less than 5% normal serum group (P<005).Conclusion serum of qishen yiqi pill can inhibit vascular smooth muscle cell proliferation, may be through inhibiting cell cycle protein Cyclin D1 and CDK4 expression, block the cell cycle G1 process is closely related to the role. 展开更多
关键词 The medicated serum of qishen yiqi PILL cell cycle VASCULAR smooth muscle cells CCK8 CYCLIN D1 CDK4
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