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Fragipan Horizon Changes Using Annual Ryegrass and Other Admendments
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作者 Lloyd Murdock Anastasios Karathanasis +2 位作者 Dottie Call Dana L. Dinnes Amitava Chatterjee 《Open Journal of Soil Science》 2024年第6期388-397,共10页
A greenhouse experiment was conducted involving intact fragipan soil cores of 50 cm thickness after removing the topsoil horizons. The cores were maintained in moist condition throughout the experiment and received se... A greenhouse experiment was conducted involving intact fragipan soil cores of 50 cm thickness after removing the topsoil horizons. The cores were maintained in moist condition throughout the experiment and received several treatments with various amendments for different periods ranging from 9 to 17 months. The amendments included annual ryegrass or Festulolium residues, powder limestone and various humate compounds alone or in combination with the grass residues. The results suggested a significant effect of ryegrass and Festulolium in reducing penetration resistance into the top 10 cm of the fragipan within 9 - 17 months, particularly when used in combination with certain humate materials such as Leonardite. Apparently, this is the result of the release of certain soluble organic compounds from the plant residues or the humate amendments that increase the solubility of Si and Al associated with the fragipan brittleness, thus decreasing the density of the compacted fragipan material. 展开更多
关键词 Fragipan Fragipan Horizon Fragipan Soils changing the Fragipan Annual Ryegrass changes Fragipan Festulolium changes Fragipan Amendments That change the Fragipan
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Mapping Energy Expansion: Remote Sensing Insights into Oil and Gas Infrastructure and Land Use Changes in Midland, TX
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作者 Nastaran Abdoli Mahdi Alipour Mehrnaz Pasokhi 《Journal of Geoscience and Environment Protection》 2024年第7期89-108,共20页
Rapid expansion in global energy demand driven primarily by oil and gas consumption has spurred significant environmental concerns. This study delves into the intricate relationship between energy development and envi... Rapid expansion in global energy demand driven primarily by oil and gas consumption has spurred significant environmental concerns. This study delves into the intricate relationship between energy development and environmental impacts focusing on Midland County, Texas, a pivotal region within the Permian Basin. Leveraging satellite imagery and Geographic Information Systems (GIS) techniques, the research meticulously examines land use dynamics from 2001 to 2019. The findings illuminate a marked decline in vegetation health and density attributable to the burgeoning oil and gas infrastructure in the area. Moreover, the analysis underscores the emergence of barren lands and the displacement of agricultural areas, indicative of the profound alterations in land cover patterns over the study period. These insights underscore the urgent need for concerted efforts to mitigate the adverse environmental effects of energy expansion, emphasizing the importance of collaborative approaches to foster sustainable land use practices. Additionally, the study explores the socio-economic implications of land use changes, addressing how energy expansion affects local communities and economies. Previous studies have emphasized the need for comprehensive assessments of cumulative environmental impacts, advocating for the implementation of effective mitigation strategies. 展开更多
关键词 Remote Sensing Land Cover change Energy Infrastructure Energy Sprawl Texas
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高效低时延分级多PAN太赫兹无线网络MAC层优化协议
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作者 刘洋 任智 +1 位作者 古金东 周逊 《小型微型计算机系统》 CSCD 北大核心 2024年第8期1966-1971,共6页
针对现有分级多PAN太赫兹无线网络MAC(Medium Access Control)协议中存在的子网形成方案不合理以及私有CTA(Channel Time Allocation)与子网内实际负载不匹配等问题,提出了一种高效低时延的MAC层优化协议.该协议采用基于泛听的按需形成... 针对现有分级多PAN太赫兹无线网络MAC(Medium Access Control)协议中存在的子网形成方案不合理以及私有CTA(Channel Time Allocation)与子网内实际负载不匹配等问题,提出了一种高效低时延的MAC层优化协议.该协议采用基于泛听的按需形成子网机制避免了子网分布不均匀以及因子网形成后没有节点加入而造成的私有CTA资源浪费的问题.在子网形成后,子微微网协调器(Piconet Coordinator,PNC)根据子网内实际负载情况自适应选择私有CTA时隙资源优化机制,让有数据传输需求的节点及时将数据发出.仿真结果表明,所提出的方案能有效地降低数据帧平均接入时延,提高吞吐量以及数据帧的传输成功率. 展开更多
关键词 太赫兹 分级 pan 无线网络 媒体访问控制协议 低时延
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ZnO@PAN柔性复合纳米纤维膜的制备及压电特性
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作者 张瑞 李银辉 +2 位作者 高飞 梁建国 李朋伟 《微纳电子技术》 CAS 2024年第6期45-53,共9页
采用静电纺丝技术,通过两步低温水热法制备了ZnO@聚丙烯腈(PAN)柔性复合纳米纤维膜。研究了静电纺丝电压和滚筒转速对ZnO@PAN柔性复合纳米纤维膜压电和铁电性能的影响。研究结果表明,当静电纺丝电压为20 kV、滚筒速度为1000 r/min时,ZnO... 采用静电纺丝技术,通过两步低温水热法制备了ZnO@聚丙烯腈(PAN)柔性复合纳米纤维膜。研究了静电纺丝电压和滚筒转速对ZnO@PAN柔性复合纳米纤维膜压电和铁电性能的影响。研究结果表明,当静电纺丝电压为20 kV、滚筒速度为1000 r/min时,ZnO@PAN柔性复合纳米纤维膜的输出性能达到最佳,输出开路电压可达到5.5 V,短路电流可达到0.61μA,剩余极化强度可达到0.43μC/cm^(2)。在外部负载电阻为13 MΩ时,柔性复合纳米纤维膜达到最大输出功率0.63μW。经过5000次循环敲击测试,所制备的ZnO@PAN柔性复合纳米纤维膜输出性能保持稳定。通过ZnO@PAN柔性复合纳米纤维膜可实时监测握力器微握、半握、全握三种不同的状态,在自供电柔性压力传感器领域有着广阔的应用前景。 展开更多
关键词 ZnO@聚丙烯腈(pan) 柔性复合纳米纤维膜 静电纺丝技术 压力传感器 柔性材料
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CBCT与PAN预测下颌近中低位阻生第三磨牙拔除术损伤水平的临床比较
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作者 刘喆 武辉 黎昌学 《牙体牙髓牙周病学杂志》 2024年第3期142-146,共5页
目的:运用锥形束CT(CBCT)及口腔曲面断层片(PAN)引导拔除下颌近中低位第三磨牙,探讨CBCT作为术前预测手段是否存在优越性。方法:选取于2022年1月至2023年8月在石河子大学第一附属医院就诊的213例患者,分为PAN组和CBCT组,对两组患者分别... 目的:运用锥形束CT(CBCT)及口腔曲面断层片(PAN)引导拔除下颌近中低位第三磨牙,探讨CBCT作为术前预测手段是否存在优越性。方法:选取于2022年1月至2023年8月在石河子大学第一附属医院就诊的213例患者,分为PAN组和CBCT组,对两组患者分别进行拔牙手术,采集患者术前及术后龈沟液并采用酶联免疫吸附实验(ELISA)测定炎症及疼痛因子浓度;运用统计学方法对比两组在各类指标的差异性。结果:CBCT作为术前评估手段相较传统PAN在明确牙根与MC接触关系上具有优越性(P <0.05),且CBCT组手术时间短、手术并发症发生率低(P <0.05);通过ELISA测定结果得出CBCT组患者龈沟液中炎症因子及疼痛因子的术前术后浓度变化值相较PAN组浓度变化值低(P <0.05)。结论:CBCT相比PAN在评估牙根与下颌管(MC)接触关系这类风险因素方面具有优越性,且应用CBCT作为术前评估手段进行拔牙手术其手术时间短,并发症少,术后损伤小。 展开更多
关键词 pan CBCT 下颌近中低位第三磨牙
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Hydraulic and volume change behaviors of compacted highly expansive soil under cyclic wetting and drying 被引量:4
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作者 Mohamed Farid Abbas Abdullah Ali Shaker Mosleh A.Al-Shamrani 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第2期486-499,共14页
The wide engineered application of compacted expansive soils necessitates understanding their behavior under field conditions.The results of this study demonstrate how seasonal climatic variation and stress and bounda... The wide engineered application of compacted expansive soils necessitates understanding their behavior under field conditions.The results of this study demonstrate how seasonal climatic variation and stress and boundary conditions individually or collectively influence the hydraulic and volume change behavior of compacted highly expansive soils.The cyclic wetting and drying(CWD)process was applied for two boundary conditions,i.e.constant stress(CS)and constant volume(CV),and for a wide range of axial stress states.The adopted CWD process affected the hydraulic and volume change behaviors of expansive soils,with the first cycle of wetting and drying being the most effective.The CWD process under CS conditions resulted in shrinkage accumulation and reduction in saturated hydraulic conductivity(k sat).On the other hand,CWD under CV conditions caused a reduction of swell pressure while has almost no impact on k sat.An elastic response to CWD was achieved after the third cycle for saturated hydraulic conductivity(k sat),the third to fourth cycle for the volume change potential under the CV conditions,and the fourth to fifth cycle for the volume change potential under the CS conditions.Finally,both swell pressure(s s)and saturated hydraulic conductivity(k sat)are not fundamental parameters of the expansive soil but rather depend on stress,boundary and wetting conditions. 展开更多
关键词 Expansive soils Hydraulic conductivity Volume change potential Cyclic wetting and drying(CWD) Swell pressure
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基于BTO/PAN复合纳米纤维膜的柔性压电纳米发电机
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作者 马俊格 李银辉 +2 位作者 耿爱森 梁建国 李朋伟 《微纳电子技术》 CAS 2024年第9期74-82,共9页
采用简单的一步水热法合成了钛酸钡纳米颗粒(BTO NP),通过静电纺丝法制备了BTO/聚丙烯腈(PAN)复合纳米纤维膜,并基于该膜制备了柔性复合压电纳米发电机。研究结果表明,随着BTO掺杂质量分数的增加,BTO/PAN柔性复合压电纳米发电机的输出... 采用简单的一步水热法合成了钛酸钡纳米颗粒(BTO NP),通过静电纺丝法制备了BTO/聚丙烯腈(PAN)复合纳米纤维膜,并基于该膜制备了柔性复合压电纳米发电机。研究结果表明,随着BTO掺杂质量分数的增加,BTO/PAN柔性复合压电纳米发电机的输出电压先增大后减小。当BTO的质量分数为15%时,BTO/PAN柔性复合压电纳米发电机的输出性能最佳,输出电压可达10.2 V,输出电流可达1.52μA。当负载电阻为12 MΩ时,其最大输出功率约为3.72μW,与纯PAN纳米纤维膜压电纳米发电机相比,输出性能有明显改善。经过5000次循环测试结果表明,BTO/PAN柔性复合压电纳米电机的的输出性能没有明显变化,因此其具有较好的稳定性。同时,该压电纳米发电机能够检测人体的不同状态,为研发高性能和自供电的可穿戴生物电子产品提供了参考。 展开更多
关键词 压电纳米发电机 纳米纤维 静电纺丝 纳米颗粒(NP) 聚丙烯腈(pan) 钛酸钡(BTO)
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参芪蛭龙汤含药血清对PAN损伤MPC5细胞凋亡的抑制作用
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作者 薛丕良 王文文 +2 位作者 李星宇 刘星 王顺 《辽宁中医杂志》 CAS 北大核心 2024年第4期196-199,I0004,共5页
目的探讨参芪蛭龙汤含药血清对puromycin aminonucleoside(PAN)损伤MPC5细胞凋亡的抑制作用。方法制备参芪蛭龙汤大鼠含药血清。MPC5细胞随机分为空白组、模型组、给药组,空白组和模型组用10%大鼠空白血清干预,给药组用10%参芪蛭龙汤含... 目的探讨参芪蛭龙汤含药血清对puromycin aminonucleoside(PAN)损伤MPC5细胞凋亡的抑制作用。方法制备参芪蛭龙汤大鼠含药血清。MPC5细胞随机分为空白组、模型组、给药组,空白组和模型组用10%大鼠空白血清干预,给药组用10%参芪蛭龙汤含药血清干预,培养24 h后,模型组和给药组加入50 mg/L的PAN干预24 h后,倒置显微镜下观察MPC5细胞的形态结构,MTS法检测细胞增殖,Hoechst33342/PI染色法检测细胞凋亡,AnnexinV-FITC/PI双染法检测细胞凋亡,Western-blot法检测MPC5细胞中BAX、Bcl-2、Caspase-3、Nephrin、Podocin蛋白的表达。结果与模型组比较,足突结构较明显,数量较多;能够促进PAN处理后MPC5细胞的增殖(P<0.05);降低细胞凋亡率(P<0.05,P<0.01);降低细胞中Bax蛋白的表达(P<0.01)、降低cleaved-Caspase-3/Caspase-3蛋白比值(P<0.05),升高Bcl-2、Nephrin蛋白的表达(P<0.05,P<0.01)。结论参芪蛭龙汤能够修复裂孔隔膜蛋白、减少足细胞凋亡,对维持肾小球的正常滤过功能具有改善作用,从而减少蛋白尿。 展开更多
关键词 膜性肾病 足细胞 pan 细胞凋亡 裂孔隔膜
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KH-560处理时间对PAN基碳纤维沥青复合材料性能的影响
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作者 曹国斌 张燕 《功能材料》 CAS CSCD 北大核心 2024年第4期4223-4229,共7页
以硅烷偶联剂KH-560改性的PAN基碳纤维为添加材料,制备了不同KH-560处理时间的PAN基碳纤维沥青复合材料。通过车辙试验、冻融劈裂试验和间接拉伸疲劳试验等研究了KH-560处理时间对沥青复合材料高温稳定性、低温抗裂性、水稳定性、疲劳... 以硅烷偶联剂KH-560改性的PAN基碳纤维为添加材料,制备了不同KH-560处理时间的PAN基碳纤维沥青复合材料。通过车辙试验、冻融劈裂试验和间接拉伸疲劳试验等研究了KH-560处理时间对沥青复合材料高温稳定性、低温抗裂性、水稳定性、疲劳性能和吸声性能的影响。结果表明,经过KH-560处理后的PAN基碳纤维表面的粗糙度增加,当KH-560处理时间为2 h时,纤维凹槽较深,与沥青的作用面积增大,纤维在复合材料中形成了致密网状结构,增强了PAN基碳纤维复合材料的稳定性。当KH-560处理时间为2 h时,PAN基碳纤维沥青复合材料的高温性能、低温抗裂性能、水稳定性和疲劳性能均最佳,此时其45和60 min的变形量、破坏劲度模量达到最小值,分别为1.851和2.117 mm、2 201 MPa;动稳定度、劈裂抗拉强度和破坏拉伸应变达到最大值,分别为3 077次/mm、4.6 MPa和3479με。在250~1 000 Hz和1 000~1 600 Hz范围内,当KH-560处理时间为2 h时,沥青复合材料的平均吸声系数均达到最大值,分别为0.116和0.127,较未处理的沥青复合材料分别提高了39.76%和45.98%,吸声降噪性能提升显著。综上可知,KH-560的最佳处理时间为2 h。 展开更多
关键词 KH-560处理 pan基碳纤维 沥青 复合材料 疲劳性能 吸声性能
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苏皖鲁豫典型城市过氧乙酰硝酸酯(PAN)污染特征分析 被引量:1
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作者 秦志勇 张红 +4 位作者 汪水兵 洪星园 王馨琦 朱森 卫尤文 《环境化学》 CAS CSCD 北大核心 2024年第5期1599-1607,共9页
为探究苏皖鲁豫区域光化学污染特征,于2021年10月和2022年6月在淮北市开展光化学污染产物过氧乙酰硝酸酯(peroxyacetyl nitrate,PAN)的在线监测,分析了PAN浓度特征、空间来源、产生速率和变化趋势.观测结果表明,观测处2021年10月PAN的... 为探究苏皖鲁豫区域光化学污染特征,于2021年10月和2022年6月在淮北市开展光化学污染产物过氧乙酰硝酸酯(peroxyacetyl nitrate,PAN)的在线监测,分析了PAN浓度特征、空间来源、产生速率和变化趋势.观测结果表明,观测处2021年10月PAN的浓度范围为(0.08—1.44)×10^(−9),2022年6月的浓度范围为(0.61—5.72)×10^(−9);PAN的峰值大部分出现在NO/NO_(2)比值较低的时段.结合气团后向轨迹,2021年10月观测处PAN的潜在源贡献函数(PSCF)高值区范围出现在南部方向,可能是因为西南方向相近城市较高的前体物排放;2022年6月高值区主要出现在北部和东南部,显示山东省西南部是潜在源贡献地区,东南方向的气团在工业化程度较高的城市群之间存在长距离运输. 展开更多
关键词 过氧乙酰硝酸酯 (pan) 光化学污染特征 苏皖鲁豫 在线监测
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Recent advances in graphene-based phase change composites for thermal energy storage and management 被引量:2
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作者 Qiang Zhu Pin Jin Ong +4 位作者 Si Hui Angela Goh Reuben J.Yeo Suxi Wang Zhiyuan Liu Xian Jun Loh 《Nano Materials Science》 EI CAS CSCD 2024年第2期115-138,共24页
Energy storage and conservation are receiving increased attention due to rising global energy demands.Therefore,the development of energy storage materials is crucial.Thermal energy storage(TES)systems based on phase ... Energy storage and conservation are receiving increased attention due to rising global energy demands.Therefore,the development of energy storage materials is crucial.Thermal energy storage(TES)systems based on phase change materials(PCMs)have increased in prominence over the past two decades,not only because of their outstanding heat storage capacities but also their superior thermal energy regulation capability.However,issues such as leakage and low thermal conductivity limit their applicability in a variety of settings.Carbon-based materials such as graphene and its derivatives can be utilized to surmount these obstacles.This study examines the recent advancements in graphene-based phase change composites(PCCs),where graphene-based nanostructures such as graphene,graphene oxide(GO),functionalized graphene/GO,and graphene aerogel(GA)are incorporated into PCMs to substantially enhance their shape stability and thermal conductivity that could be translated to better storage capacity,durability,and temperature response,thus boosting their attractiveness for TES systems.In addition,the applications of these graphene-based PCCs in various TES disciplines,such as energy conservation in buildings,solar utilization,and battery thermal management,are discussed and summarized. 展开更多
关键词 Phase change material NANOCOMPOSITES Solar energy Sustainable energy Thermo-regulation
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Experimental study on thermal and mechanical properties of tailings-based cemented paste backfill with CaCl_(2)·6H_(2)O/expanded vermiculite shape stabilized phase change materials 被引量:2
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作者 Xiaoyan Zhang Tianrun Cao +3 位作者 Lang Liu Baoyun Bu Yaping Ke Qiangqiang Du 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第2期250-259,共10页
CaCl_(2)·6H_(2)O/expanded vermiculite shape stabilized phase change materials(CEV)was prepared by atmospheric impregnation method.Using gold mine tailings as aggregate of cemented paste backfill(CPB)material,the ... CaCl_(2)·6H_(2)O/expanded vermiculite shape stabilized phase change materials(CEV)was prepared by atmospheric impregnation method.Using gold mine tailings as aggregate of cemented paste backfill(CPB)material,the CPB with CEV added was prepared,and the specific heat capacity,thermal conductivity,and uniaxial compressive strength(UCS)of CPB with different cement-tailing ratios and CEV addition ratios were tested,the influence of the above variables on the thermal and mechanical properties of CPB was analyzed.The results show that the maximum encapsulation capacity of expanded vermiculite for CaCl_(2)·6H_(2)O is about 60%,and the melting and solidification enthalpies of CEV can reach 98.87 J/g and 97.56 J/g,respectively.For the CPB without CEV,the specific heat capacity,thermal conductivity,and UCS decrease with the decrease of cement-tailing ratio.For the CPB with CEV added,with the increase of CEV addition ratio,the specific heat capacity increases significantly,and the sensible heat storage capacity and latent heat storage capacity can be increased by at least 10.74%and 218.97%respectively after adding 12%CEV.However,the addition of CEV leads to the increase of pores,and the thermal conductivity and UCS both decrease with the increase of CEV addition.When cement-tailing ratio is 1:8 and 6%,9%,and 12%of CEV are added,the 28-days UCS of CPB is less than 1 MPa.Considering the heat storage capacity and cost price of backfill,the recommended proportion scheme of CPB material presents cement-tailing ratio of 1:6 and 12%CEV,and the most recommended heat storage/release temperature cycle range of CPB with added CEV is from 20 to 40℃.This work can provide theoretical basis for the utilization of heat storage backfill in green mines. 展开更多
关键词 CaCl_(2)·6H_(2)O/expanded vermiculite shape stabilized phase change materials cemented paste backfill thermal property mechanical property
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基于统计损伤修正的冻结砂—黏混合土改进Duncan-Chang模型
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作者 滕振超 李正巍 +7 位作者 刘佳琳 周亚东 李波 刘彦峰 池林林 张圣童 刘博 计静 《东北石油大学学报》 CAS 北大核心 2024年第2期116-124,I0008,共10页
为描述冻结砂—黏混合土的偏应力—应变关系,进行不同含砂量冻结砂—黏混合土的冻土三轴压缩试验。基于改进的Duncan-Chang模型(D-C模型),引入统计损伤理论,拟合三轴压缩试验结果,分别建立以Mises强度准则和应变发展为微元强度变量的统... 为描述冻结砂—黏混合土的偏应力—应变关系,进行不同含砂量冻结砂—黏混合土的冻土三轴压缩试验。基于改进的Duncan-Chang模型(D-C模型),引入统计损伤理论,拟合三轴压缩试验结果,分别建立以Mises强度准则和应变发展为微元强度变量的统计损伤修正模型,对比计算结果与试验数据。结果表明:冻结砂—黏混合土偏应力峰值随含砂量的增加而增加,偏应力—应变曲线由应变硬化型逐渐过渡到应变软化型的临界含砂量为50%。当含砂量介于20%~60%时,基于统计损伤理论的修正改进D-C模型能有效拟合应变硬化型曲线和具有轻微应变软化现象的偏应力—应变曲线。当含砂量为90%时,基于应变发展的统计损伤修正模型的偏应力峰值与试验结果相差3%,具有较强适用性。该结果为不同微元强度变量的统计损伤修正模型提供参考。 展开更多
关键词 冻结砂—黏混合土 三轴压缩试验 改进Duncan-chang模型 统计损伤理论 应变软化模型
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Global Change in Agricultural Flash Drought over the 21st Century 被引量:1
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作者 Emily BLACK 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第2期209-220,I0002-I0019,共30页
Agricultural flash droughts are high-impact phenomena, characterized by rapid soil moisture dry down. The ensuing dry conditions can persist for weeks to months, with detrimental effects on natural ecosystems and crop... Agricultural flash droughts are high-impact phenomena, characterized by rapid soil moisture dry down. The ensuing dry conditions can persist for weeks to months, with detrimental effects on natural ecosystems and crop cultivation. Increases in the frequency of these rare events in a future warmer climate would have significant societal impact. This study uses an ensemble of 10 Coupled Model Intercomparison Project(CMIP) models to investigate the projected change in agricultural flash drought during the 21st century. Comparison across geographical regions and climatic zones indicates that individual events are preceded by anomalously low relative humidity and precipitation, with long-term trends governed by changes in temperature, relative humidity, and soil moisture. As a result of these processes, the frequency of both upperlevel and root-zone flash drought is projected to more than double in the mid-and high latitudes over the 21st century, with hot spots developing in the temperate regions of Europe, and humid regions of South America, Europe, and southern Africa. 展开更多
关键词 flash drought climate change soil moisture agricultural drought CMIP
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Shikimic acid accelerates phase change and flowering in Chinese jujube 被引量:1
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作者 Xianwei Meng Zhiguo Liu +11 位作者 Li Dai Weiqiang Zhao Jiurui Wang Lili Wang Yuanpei Cui Ying Li Yinshan Cui Yao Zhang Luyao Wang Fengjiao Yu Jin Zhao Mengjun Liu 《Horticultural Plant Journal》 SCIE CAS CSCD 2024年第2期413-424,共12页
The juvenile-to-adult phase change with first flowering as the indicator plays a crucial role in the lifecycle of fruit trees. However, the molecular mechanisms underlying phase change in fruit trees remain largely un... The juvenile-to-adult phase change with first flowering as the indicator plays a crucial role in the lifecycle of fruit trees. However, the molecular mechanisms underlying phase change in fruit trees remain largely unknown. Shikimic acid (ShA) pathway is a main metabolic pathway closely related to the synthesis of hormones and many important secondary metabolites participating in plant phase change. So,whether ShA regulates phase change in plants is worth clarifying. Here, the distinct morphological characteristics and the underlying mechanisms of phase change in jujube (Ziziphus jujuba Mill.), an important fruit tree native to China with nutritious fruit and outstanding tolerance abiotic stresses, were clarified. A combined transcriptome and metabolome analysis found that ShA is positively involved in jujube(Yuhong’×Xing 16’) phase change. The genes in the upstream of ShA synthesis pathway (ZjDAHPS, ZjDHQS and ZjSDH), the contents of ShA and the downstream secondary metabolites like phenols were significantly upregulated in the phase change period. Further, the treatment of spraying exogenous ShA verified that ShA at a very low concentration (60 mg·L^(-1)) can substantially speed up the phase change and flowering of jujube and other tested plants including Arabidopsis, tomato and wheat. The exogenous ShA (60 mg·L^(-1)) treatment in jujube seedlings could increase the accumulation of endogenous ShA, enhance leaf photosynthesis and the synthesis of phenols especially flavonoids and phenolic acids, and promote the expression of genes (ZjCOs, ZjNFYs and ZjPHYs) involved in flowering pathway. Basing on above results, we put forward a propose for the underlying mechanism of ShA regulating phase change, and a hypothesis that ShA could be considered a phytohormone-like substance because it is endogenous, ubiquitous, movable and highly efficient at very low concentrations. This study highlights the critical role of ShA in plant phase change and its phytohormone-like properties. 展开更多
关键词 Ziziphus jujuba Mill. Phase change FLOWERING Shikimic acid TRANSCRIPTOME METABOLOME
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五味子乙素对胰腺癌Pan02细胞增殖的抑制作用及其机制 被引量:1
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作者 傅家财 秦玲莎 +5 位作者 杨露 宋美慧 张仙映 刘晓翠 李凤金 齐玲 《吉林大学学报(医学版)》 CAS CSCD 北大核心 2024年第3期638-646,共9页
目的:探讨五味子乙素对胰腺癌Pan02细胞增殖的抑制作用,并阐明其作用机制。方法:采用CCK-8法检测不同浓度(0、0.78、1.56、3.12、6.25、12.50和25.00 mg·L^(-1))五味子乙素作用下Pan02细胞增殖率,以选择五味子乙素作用的最适浓度... 目的:探讨五味子乙素对胰腺癌Pan02细胞增殖的抑制作用,并阐明其作用机制。方法:采用CCK-8法检测不同浓度(0、0.78、1.56、3.12、6.25、12.50和25.00 mg·L^(-1))五味子乙素作用下Pan02细胞增殖率,以选择五味子乙素作用的最适浓度和最佳作用时间。小鼠胰腺癌Pan02细胞分为对照组(0 mg·L^(-1)五味子乙素)、2.5 mg·L^(-1)五味子乙素组、5.0 mg·L^(-1)五味子乙素组和10.0 mg·L^(-1)五味子乙素组。光学显微镜观察各组Pan02细胞形态表现,5-乙基-2'-脱氧尿嘧啶核苷(EdU)染色法检测各组Pan02细胞中EdU阳性细胞率,流式细胞术检测各组不同细胞周期Pan02细胞百分率和细胞凋亡率,Western blotting法检测各组Pan02细胞周期和凋亡相关蛋白表达水平。结果:CCK-8法,五味子乙素作用Pan02细胞48和72 h后,与0 mg·L^(-1)五味子乙素比较,其他浓度五味子乙素作用下Pan02细胞增殖率明显降低(P<0.01),72 h时细胞抑制作用最明显。选择0、2.5、5.0和10.0 mg·L^(-1)五味子乙素作用Pan02细胞,作用时间为72 h。对照组Pan02细胞呈长梭形,状态良好,紧密且贴壁生长,细胞器和细胞质正常;2.5和5.0 mg·L^(-1)五味子乙素组Pan02细胞体积减小,细胞之间黏连消失,细胞膜虽完整但通透性增强,细胞质皱缩,细胞内部产生空泡结构,部分呈碎片状漂浮于溶液表面;10.0 mg·L^(-1)五味子乙素组Pan02细胞有明显凋亡小体生成,呈现凋亡状态。EdU染色法,与对照组比较,2.5、5.0和10.0 mg·L^(-1)五味子乙素组Pan02细胞中EdU阳性细胞率均明显降低(P<0.01)。流式细胞术,与对照组比较,2.5、5.0和10.0 mg·L^(-1)五味子乙素组Pan02细胞S期细胞百分率明显升高(P<0.01),G_(2)/M期细胞百分率明显降低(P<0.01),5.0和10.0 mg·L^(-1)五味子乙素组G_(0)/G_(1)期细胞百分率明显降低(P<0.01);与对照组比较,2.5、5.0和10.0 mg·L^(-1)五味子乙素组Pan02细胞凋亡率明显升高(P<0.01)。Western blotting法,与对照组比较,2.5 mg·L^(-1)五味子乙素组Pan02细胞中p27、B细胞淋巴瘤2(Bcl-2)相关X蛋白(Bax)、裂解的半胱氨酸天冬氨酸蛋白酶3(cleaved Caspase-3)和裂解的多聚二磷酸腺苷(ADP)核糖聚合酶(cleaved PARP)蛋白表达水平明显升高(P<0.05或P<0.01);5.0和10.0 mg·L^(-1)五味子乙素组Pan02细胞中细胞周期蛋白(Cyclin)A2、Cyclin E2和Bcl-2蛋白表达水平均明显降低(P<0.05或P<0.01),p27、 Bax、 cleaved Caspase-3和cleaved PARP蛋白表达水平均明显升高(P<0.01)。结论:五味子乙素具有抑制胰腺癌Pan02细胞增殖的作用,其作用机制可能与激活半胱氨酸天冬氨酸蛋白酶3(Caspase-3)通路诱导细胞凋亡和激活p27蛋白并诱导细胞周期S期阻滞有关。 展开更多
关键词 五味子乙素 胰腺肿瘤 pan02细胞 细胞凋亡 细胞周期
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Projected changes in extreme snowfall events over the Tibetan Plateau based on a set of RCM simulations 被引量:1
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作者 Yuanhai Fu Xuejie Gao 《Atmospheric and Oceanic Science Letters》 CSCD 2024年第5期3-9,共7页
Extreme snowfall events over the Tibetan Plateau(TP)cause considerable damage to local society and natural ecosystems.In this study,the authors investigate the projected changes in such events over the TP and its surr... Extreme snowfall events over the Tibetan Plateau(TP)cause considerable damage to local society and natural ecosystems.In this study,the authors investigate the projected changes in such events over the TP and its surrounding areas based on an ensemble of a set of 21st century climate change projections using a regional climate model,RegCM4.The model is driven by five CMIP5 global climate models at a grid spacing of 25 km,under the RCP4.5 and RCP8.5 pathways.Four modified ETCCDI extreme indices-namely,SNOWTOT,S1mm,S10mm,and Sx5day-are employed to characterize the extreme snowfall events.RegCM4 generally reproduces the spatial distribution of the indices over the region,although with a tendency of overestimation.For the projected changes,a general decrease in SNOWTOT is found over most of the TP,with greater magnitude and better cross-simulation agreement over the eastern part.All the simulations project an overall decrease in S1mm,ranging from a 25%decrease in the west and to a 50%decrease in the east of the TP.Both S10mm and Sx5day are projected to decrease over the eastern part and increase over the central and western parts of the TP.Notably,S10mm shows a marked increase(more than double)with high cross-simulation agreement over the central TP.Significant increases in all four indices are found over the Tarim and Qaidam basins,and northwestern China north of the TP.The projected changes show topographic dependence over the TP in the latitudinal direction,and tend to decrease/increase in low-/high-altitude areas. 展开更多
关键词 Extreme snowfall Regional climate model Tibetan plateau Climate change
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Climate change drives flooding risk increases in the Yellow River Basin 被引量:1
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作者 Hengxing Lan Zheng Zhao +9 位作者 Langping Li Junhua Li Bojie Fu Naiman Tian Ruixun Lai Sha Zhou Yanbo Zhu Fanyu Zhang Jianbing Peng John J.Clague 《Geography and Sustainability》 CSCD 2024年第2期193-199,共7页
The Yellow River Basin(YRB)has experienced severe floods and continuous riverbed elevation throughout history.Global climate change has been suggested to be driving a worldwide increase in flooding risk.However,owing ... The Yellow River Basin(YRB)has experienced severe floods and continuous riverbed elevation throughout history.Global climate change has been suggested to be driving a worldwide increase in flooding risk.However,owing to insufficient evidence,the quantitative correlation between flooding and climate change remains illdefined.We present a long time series of maximum flood discharge in the YRB dating back to 1843 compiled from historical documents and instrument measurements.Variations in yearly maximum flood discharge show distinct periods:a dramatic decreasing period from 1843 to 1950,and an oscillating gentle decreasing from 1950 to 2021,with the latter period also showing increasing more extreme floods.A Mann-Kendall test analysis suggests that the latter period can be further split into two distinct sub-periods:an oscillating gentle decreasing period from 1950 to 2000,and a clear recent increasing period from 2000 to 2021.We further predict that climate change will cause an ongoing remarkable increase in future flooding risk and an∼44.4 billion US dollars loss of floods in the YRB in 2100. 展开更多
关键词 Flooding risk Risk management Climate change Flood discharge Extreme precipitation
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Self‑Assembly of Binderless MXene Aerogel for Multiple‑Scenario and Responsive Phase Change Composites with Ultrahigh Thermal Energy Storage Density and Exceptional Electromagnetic Interference Shielding 被引量:1
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作者 Chuanbiao Zhu Yurong Hao +8 位作者 Hao Wu Mengni Chen Bingqing Quan Shuang Liu Xinpeng Hu Shilong Liu Qinghong Ji Xiang Lu Jinping Qu 《Nano-Micro Letters》 SCIE EI CSCD 2024年第3期367-382,共16页
The severe dependence of traditional phase change materials(PCMs)on the temperature-response and lattice deficiencies in versatility cannot satisfy demand for using such materials in complex application scenarios.Here... The severe dependence of traditional phase change materials(PCMs)on the temperature-response and lattice deficiencies in versatility cannot satisfy demand for using such materials in complex application scenarios.Here,we introduced metal ions to induce the self-assembly of MXene nanosheets and achieve their ordered arrangement by combining suction filtration and rapid freezing.Subsequently,a series of MXene/K^(+)/paraffin wax(PW)phase change composites(PCCs)were obtained via vacuum impregnation in molten PW.The prepared MXene-based PCCs showed versatile applications from macroscale technologies,successfully transforming solar,electric,and magnetic energy into thermal energy stored as latent heat in the PCCs.Moreover,due to the absence of binder in the MXene-based aerogel,MK3@PW exhibits a prime solar-thermal conversion efficiency(98.4%).Notably,MK3@PW can further convert the collected heat energy into electric energy through thermoelectric equipment and realize favorable solar-thermal-electric conversion(producing 206 mV of voltage with light radiation intensity of 200 mw cm^(−2)).An excellent Joule heat performance(reaching 105℃with an input voltage of 2.5 V)and responsive magnetic-thermal conversion behavior(a charging time of 11.8 s can achieve a thermal insulation effect of 285 s)for contactless thermotherapy were also demonstrated by the MK3@PW.Specifically,as a result of the ordered arrangement of MXene nanosheet self-assembly induced by potassium ions,MK3@PW PCC exhibits a higher electromagnetic shielding efficiency value(57.7 dB)than pure MXene aerogel/PW PCC(29.8 dB)with the same MXene mass.This work presents an opportunity for the multi-scene response and practical application of PCMs that satisfy demand of next-generation multifunctional PCCs. 展开更多
关键词 Self-assembly Multiple-scenario Phase change composites Thermal energy storage Electromagnetic interference shielding
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Timing theory integrated nursing combined behavior change integrated theory of nursing on primiparous influence 被引量:1
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作者 Yan-Xia He Yang Lv +2 位作者 Ting-Ting Lan Fang Deng Yuan-Yuan Zhang 《World Journal of Clinical Cases》 SCIE 2024年第2期293-301,共9页
BACKGROUND The comprehension and utilization of timing theory and behavior change can offer a more extensive and individualized provision of support and treatment alternatives for primipara.This has the potential to e... BACKGROUND The comprehension and utilization of timing theory and behavior change can offer a more extensive and individualized provision of support and treatment alternatives for primipara.This has the potential to enhance the psychological well-being and overall quality of life for primipara,while also furnishing healthcare providers with efficacious interventions to tackle the psychological and physiological obstacles encountered during the stages of pregnancy and postpartum.AIM To explore the effect of timing theory combined with behavior change on selfefficacy,negative emotions and quality of life in patients with primipara.METHODS A total of 80 primipara cases were selected and admitted to our hospital between August 2020 and May 2022.These cases were divided into two groups,namely the observation group and the control group,with 40 cases in each group.The nursing interventions differed between the two groups,with the control group receiving routine nursing and the observation group receiving integrated nursing based on the timing theory and behavior change.The study aimed to compare the pre-and post-nursing scores of Chinese Perceived Stress Scale(CPSS),Edinburgh Postpartum Depression Scale(EPDS),Self-rating Anxiety Scale(SAS),breast milk knowledge,self-efficacy,and SF-36 quality of life in both groups.RESULTS After nursing,the CPSS,EPDS,and SAS scores of the two groups was significantly lower than that before nursing,and the CPSS,EPDS,and SAS scores of the observation group was significantly lower than that of the control group(P=0.002,P=0.011,and P=0.001 respectively).After nursing,the breastfeeding knowledge mastery,selfefficacy,and SF-36 quality of life scores was significantly higher than that before nursing,and the breastfeeding knowledge mastery(P=0.013),self-efficacy(P=0.008),and SF-36 quality of life(P=0.011)scores of the observation group was significantly higher than that of the control group.CONCLUSION The integration of timing theory and behavior change integrated theory has been found to be an effective approach in alleviating negative mood and stress experienced by primipara individuals,while also enhancing their selfefficacy and overall quality of life.This study focuses on the key concepts of timing theory,behavior change,primipara individuals,negative mood,and quality of life. 展开更多
关键词 Timing theory Behavior change PRIMIPARA Bad mood Quality of life
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