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国外旅游扶贫研究进展 被引量:147
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作者 李会琴 侯林春 +1 位作者 杨树旺 J R Brent ritchie 《人文地理》 CSSCI 北大核心 2015年第1期26-32,共7页
在相关概念辨析的基础上,对国外旅游扶贫理论、实践模式、效果、研究方法、相关国际组织的作用进行了综述。国外旅游扶贫形成了较为系统的理论体系与研究框架,为旅游实践提供了理论支持。从研究内容看,自然旅游、遗产旅游、农业旅游、... 在相关概念辨析的基础上,对国外旅游扶贫理论、实践模式、效果、研究方法、相关国际组织的作用进行了综述。国外旅游扶贫形成了较为系统的理论体系与研究框架,为旅游实践提供了理论支持。从研究内容看,自然旅游、遗产旅游、农业旅游、社区旅游是旅游扶贫的主要方式;从扶贫效果看,旅游扶贫对当地经济有较大的促进作用,但需要合理的规划与操控才能可持续。旅游扶贫研究方法以宏观的定量研究为主,研究案例呈现地理集中性。今后应加强城市贫困问题、精准旅游扶贫及中国旅游扶贫案例的研究。 展开更多
关键词 旅游扶贫 社区旅游 研究进展 国外
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Portal hypertension: Imaging of portosystemic collateral pathways and associated image-guided therapy 被引量:18
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作者 Murad Feroz Bandali Anirudh Mirakhur +4 位作者 Edward Wolfgang Lee Mollie Clarke Ferris David James Sadler Robin ritchie Gray Jason Kam Wong 《World Journal of Gastroenterology》 SCIE CAS 2017年第10期1735-1746,共12页
Portal hypertension is a common clinical syndrome, defined by a pathologic increase in the portal venous pressure. Increased resistance to portal blood flow, the primary factor in the pathophysiology of portal hyperte... Portal hypertension is a common clinical syndrome, defined by a pathologic increase in the portal venous pressure. Increased resistance to portal blood flow, the primary factor in the pathophysiology of portal hypertension, is in part due to morphological changes occurring in chronic liver diseases. This results in rerouting of blood flow away from the liver through collateral pathways to low-pressure systemic veins. Through a variety of computed tomographic, sonographic, magnetic resonance imaging and angiographic examples, this article discusses the appearances and prevalence of both common and less common portosystemic collateral channels in the thorax and abdomen. A brief overview of established interventional radiologic techniques for treatment of portal hypertension will also be provided. Awareness of the various imaging manifestations of portal hypertension can be helpful for assessing overall prognosis and planning proper management. 展开更多
关键词 Portal hypertension Diagnostic imaging Portosystemic collaterals Image-guided therapy
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The functional significance of dentin sialoprotein-phosphophoryn and dentin sialoprotein 被引量:12
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作者 Helena ritchie 《International Journal of Oral Science》 SCIE CAS CSCD 2018年第4期197-202,共6页
Phosphophoryn (PP) and dentin sialoprotein (DSP) are the most dominant non-collagenous proteins in dentin. PP is an extremely acidic protein that can function as a mineral nucleator for dentin mineralization. DSP was ... Phosphophoryn (PP) and dentin sialoprotein (DSP) are the most dominant non-collagenous proteins in dentin. PP is an extremely acidic protein that can function as a mineral nucleator for dentin mineralization. DSP was first identified in 1981, yet its functional significance is still controversial. Historically, these two proteins were considered to be independently synthesized and secreted by dental pulp cells into the developing dentin matrix. However, with the identification of the DSP coding sequence in 1994, followed2 years later by the finding that the PP coding sequence was located immediately downstream from the DSP sequence, it became immediately clear that DSP and PP proteins were derived from a single DSP-PP (i.e., dentin sialophosphoprotein, DSPP) transcript.Since DSPP cDNA became available, tremendous progress has been made in studying DSP-PP mRNA distribution and DSP generation from the DSP-PP precursor protein at specific cleavage sites by protease tolloid-related-1 (TLR1) or bone morphogenetic protein 1 (BMP1). The functions of DSP-PP and DSP were investigated via DSP-PP knockout (KO) and DSP knockin in DSP-PP KO mice. In addition, a number of in vitro studies aimed to elucidate DSPP and DSP function in dental pulp cells. 展开更多
关键词 DSP The functional significance of dentin sialoprotein-phosphophoryn and dentin sialoprotein
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2,5-二甲基呋喃的喷雾特性及发动机适应性 被引量:12
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作者 田国弘 徐宏明 +2 位作者 ritchie DANIEL 李海鹰 李雁飞 《汽车安全与节能学报》 CAS 2010年第2期132-140,共9页
2,5-二甲基呋喃(DMF)可作为一种可再生的汽油类替代燃料。为研究DMF在车用发动机中的适用性,该文采用相位Doppler粒子分析仪(PDPA)测试了DMF的微观喷雾特性,并在一台单缸直喷汽油机上进行了性能及排放测试。作为对比,同时对商用无铅汽... 2,5-二甲基呋喃(DMF)可作为一种可再生的汽油类替代燃料。为研究DMF在车用发动机中的适用性,该文采用相位Doppler粒子分析仪(PDPA)测试了DMF的微观喷雾特性,并在一台单缸直喷汽油机上进行了性能及排放测试。作为对比,同时对商用无铅汽油以及另一种汽油类替代燃料乙醇进行了相应测试。实验结果表明:DMF的喷雾特性与汽油相仿,而乙醇具有较低的喷雾油粒速度和较高的索特平均粒径;当使用DMF作为点燃式发动机燃料时,可以在高负荷采用更为提前的点火时间以获得更好的热效率,但总的来讲其等效油耗与汽油差别不大;另外,DMF的NOx排放较高,其他气态排放物与汽油接近。 展开更多
关键词 车用发动机 喷雾特性 燃油消耗率 气态排放 2 5-二甲基呋喃 相位Doppler粒子分析仪(PDPA)
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中加两所医院护士职业危害感知与防护现状的比较研究 被引量:9
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作者 曹洁 Judith ritchie +3 位作者 张玲娟 王利丽 沈峰平 陆小英 《中国护理管理》 2011年第6期26-29,共4页
目的:通过比较中加两所医院手术室和肿瘤科护士对职业危害的感知与职业防护现状,为中国医疗卫生保健管理部门开展深入研究,制定相关政策提供借鉴。方法:自行设计与开发护士职业危害与防护量表,并将该量表法语化与汉语化,在中加两所综合... 目的:通过比较中加两所医院手术室和肿瘤科护士对职业危害的感知与职业防护现状,为中国医疗卫生保健管理部门开展深入研究,制定相关政策提供借鉴。方法:自行设计与开发护士职业危害与防护量表,并将该量表法语化与汉语化,在中加两所综合性大学附属医院开展调查。结果:不同调查点护士年龄分布差异有统计学意义,调查对象职位分布差异无统计学意义;中国护士对生物性职业危害及总体危害的感知程度比加拿大护士高,中国护士对锐器伤、喷溅物、空气传播性生物危害的感知程度比加拿大护士高,中国护士对举/搬运大重量器具危害的感知程度比加拿大护士高,但中国护士对手术室烟雾危害的感知程度比加拿大护士低;中国医疗机构在降低护士生物性职业危害及化学性职业危害等方面所采取的相关职业防护措施力度低于加拿大。结论:跨国研究存在的文化差异显著,护士对职业危害感知与其职业防护知识背景紧密相关,我国护士职业防护面临严峻的挑战,医院应加大对临床护士职业防护教育的力度,引进先进理念与标准,进一步推动相关政策的制定。 展开更多
关键词 中国 加拿大 护士 职业危害与防护 比较研究
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One hundred and seventy-eight consecutive pancreatoduodenectomies without mortality:role of the multidisciplinary approach 被引量:8
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作者 Jaswinder S Samra Raul Alvarado Bachmann +10 位作者 Julian Choi Anthony Gill Michael Neale Vikram Puttaswamy Cameron Bell Ian Norton Sarah Cho Steven Blome ritchie Maher Sivakumar Gananadha Thomas J Hugh 《Hepatobiliary & Pancreatic Diseases International》 SCIE CAS 2011年第4期415-421,共7页
BACKGROUND:Pancreatoduodenectomy offers the only chance of cure for patients with periampullary cancers.This,however,is a major undertaking in most patients and is associated with a significant morbidity and mortality... BACKGROUND:Pancreatoduodenectomy offers the only chance of cure for patients with periampullary cancers.This,however,is a major undertaking in most patients and is associated with a significant morbidity and mortality.A multidisciplinary approach to the workup and follow-up of patients undergoing pancreatoduodenectomy was initiated at our institution to improve the diagnosis,resection rate,mortality and morbidity.We undertook the study to assess the effect of this approach on diagnosis,resection rates and short-term outcomes such as morbidity and mortality.METHODS:A prospective database of patients presenting with periampullary cancers to a single surgeon between April 2004 and April 2010 was reviewed.All cases were discussed at a multidisciplinary meeting comprising surgeons,gastroenterologists,radiologists,oncologists,radiation oncologists,pathologists and nursing staff.A standardized investigation and management algorithm was followed.Complications were graded according to the Clavien-Dindo classification.RESULTS:A total of 295 patients with a periampullary lesion were discussed and 178 underwent pancreatoduodenectomy (resection rate 60%).Sixty-one patients (34%) required either a vascular or an additional organ resection.Eighty-nine patients experienced complications,of which the commonest was blood transfusion (12%).Thirty-four patients (19%) had major complications,i.e.grade 3 or above.There was no in-hospital,30-day or 60-day mortality.CONCLUSIONS:Pancreatoduodenectomy can safely be performed in high-volume centers with very low mortality.The surgeon’s role should be careful patient selection,intensive preoperative investigations,use of a team approach,and an unbiased discussion at a multidisciplinary meeting to optimize the outcome in these patients. 展开更多
关键词 PANCREATODUODENECTOMY MULTIDISCIPLINARY vascular resection
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Cardiovascular involvement in multisystem inflammatory syndrome in children and midterm follow-up from a pediatric tertiary center in India
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作者 Poovazhagi Varadarajan ritchie Sharon Solomon +3 位作者 Seenivasan Subramani Ramesh Subramanian Gomathy Srividya Elilarasi Raghunathan 《World Journal of Clinical Pediatrics》 2025年第1期127-138,共12页
BACKGROUND In multisystem inflammatory syndrome in children(MIS-C)with coronavirus disease 2019,there was paucity of data from low-income and middle-income countries on cardiovascular involvement and its longitudinal ... BACKGROUND In multisystem inflammatory syndrome in children(MIS-C)with coronavirus disease 2019,there was paucity of data from low-income and middle-income countries on cardiovascular involvement and its longitudinal outcomes.We planned to estimate the pattern of cardiovascular involvement among children with MIS-C and its mid-term outcomes.AIM To determine association between cardiovascular abnormalities and clinical and laboratory parameters.To study the time-line for resolution of various abnormalities.METHODS In this prospective study done in a tertiary care hospital,270 were recruited from June 2020 to January 2022.Baseline demographic data and clinical presentation were recorded.Laboratory parameters and echocardiography were done at admission.Follow-up was done at 2 weeks,3 months,6 months and 1 year after diagnosis.Descriptive statistics were used for parametric and non-parametric data.Risk factors were identified by multivariate regression analysis.RESULTS The 211(78.2%)had cardiac involvement and 102 needed intensive care unit(ICU)admission.Cardiovascular abnormalities observed were shock 123(45.6%),coronary dilatation 28(10.4%),coronary aneurysm 77(28.5%),left ventricular(LV)dysfunction 78(29.3%),mitral regurgitation(MR)77(28.5%)and pericardial effusion 98(36.3%).Coronary artery aneurysm/dilatation during follow-up at 2 weeks and 1 year were 25.7%and 0.9%respectively.Multivariate regression analysis revealed breathlessness[odds ratio(OR)=3.91,95%CI:1.25-12.21,P=0.019]and hi-flow nasal cannula(HFNC)support(OR=8.5,95%CI:1.06-68.38,P=0.044)as predictors of cardiovascular involvement.Higher mean age(OR=1.16,95%CI:1.02-1.32,P=0.026),breathlessness(OR=4.99,95%CI:2.05-12.20,P<0.001),gallop(OR=4.45,95%CI:0.41-2.52,P=0.016),MR(OR=3.61,95%CI:1.53-8.53,P=0.004)and invasive ventilation(OR=4.01,95%CI:1.28-12.58,P=0.017)were predictive of LV dysfunction.Altered sensorium(OR=4.96,95%CI:2.23-11.02,P<0.001),headache(OR=6.61,95%CI:1.46-29.92,P=0.014),HFNC(OR=7.03,95%CI:2.04-24.29,P=0.002),non-rebreathing mask usage(OR=2 展开更多
关键词 Multisystem inflammatory syndrome in children Cardiovascular Midterm follow-up Coronary artery aneurysm Shock Left ventricular dysfunction
一种新型的高频半导体量子点单电子泵 被引量:5
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作者 李玲 Kaestner B +7 位作者 Blumenthal M D Giblin S Janssen T J B M Pepper M Anderson D Jones G ritchie D A 高洁 《物理学报》 SCIE EI CAS CSCD 北大核心 2008年第3期1878-1885,共8页
除了直流负电压外,还在浅法刻蚀出的GaAs/AlGaAs量子线上的两个金属指形门上分别叠加两个相位相差π的正弦信号,从而对形成量子点的两个势垒作不等幅调制.在无源漏偏压的情况下,通过周期形成的量子点实现了单电子的搬运.由于新的半导体... 除了直流负电压外,还在浅法刻蚀出的GaAs/AlGaAs量子线上的两个金属指形门上分别叠加两个相位相差π的正弦信号,从而对形成量子点的两个势垒作不等幅调制.在无源漏偏压的情况下,通过周期形成的量子点实现了单电子的搬运.由于新的半导体量子点单电子泵不是依赖库仑阻塞效应通过隧穿进行单电子输运,因此,该器件就不会受到固定隧穿时间引起的低工作频率限制.在1.7K温度下,频率达到3GHz仍然可以观测到量子化电流平台,对应的电流值达到0.5nA量级.这种新器件提供了实现高速度、高精度搬运单电子的另一种可能途径. 展开更多
关键词 单电子输运 单电子旋转门 单电子泵 量子化电流平台
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High-throughput phenotyping in cotton:a review 被引量:5
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作者 PABUAYON Irish Lorraine B SUN Yazhou +1 位作者 GUO Wenxuan ritchie Glen L 《Journal of Cotton Research》 2019年第3期174-182,共9页
Recent technological advances in cotton(Gossypium hirsutum L.) phenotyping have offered tools to improve the efficiency of data collection and analysis.High-throughput phenotyping(HTP) is a non-destructive and rapid a... Recent technological advances in cotton(Gossypium hirsutum L.) phenotyping have offered tools to improve the efficiency of data collection and analysis.High-throughput phenotyping(HTP) is a non-destructive and rapid approach of monitoring and measuring multiple phenotypic traits related to the growth,yield,and adaptation to biotic or abiotic stress.Researchers have conducted extensive experiments on HTP and developed techniques including spectral,fluorescence,thermal,and three-dimensional imaging to measure the morphological,physiological,and pathological resistance traits of cotton.In addition,ground-based and aerial-based platforms were also developed to aid in the implementation of these HTP systems.This review paper highlights the techniques and recent developments for HTP in cotton,reviews the potential applications according to morphological and physiological traits of cotton,and compares the advantages and limitations of these HTP systems when used in cotton cropping systems.Overall,the use of HTP has generated many opportunities to accurately and efficiently measure and analyze diverse traits of cotton.However,because of its relative novelty,HTP has some limitations that constrains the ability to take full advantage of what it can offer.These challenges need to be addressed to increase the accuracy and utility of HTP,which can be done by integrating analytical techniques for big data and continuous advances in imaging. 展开更多
关键词 COTTON HIGH-THROUGHPUT PHENOTYPING Remote sensing Sensors Spectral FLUORESCENCE Thermal PLATFORMS Aerial-based Ground-based
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Statistical evaluation of 571 GaAs quantum point contact transistors showing the 0.7 anomaly in quantized conductance using cryogenic on-chip multiplexing
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作者 Pengcheng Ma Kaveh Delfanazari +8 位作者 Reuben K.Puddy Jiahui Li Moda Cao Teng Yi Jonathan P.Griffiths Harvey E.Beere David A.ritchie Michael J.Kelly Charles G.Smith 《Chip》 EI 2024年第3期21-28,共8页
Themass production and the practical number of cryogenic quantum devices producible in a single chip are limited to the number of electrical contact pads and wiring of the cryostat or dilution refrigerator.It is,there... Themass production and the practical number of cryogenic quantum devices producible in a single chip are limited to the number of electrical contact pads and wiring of the cryostat or dilution refrigerator.It is,therefore,beneficial to contrast themeasurements of hundreds of devices fabricated in a single chip in one cooldown process to promote the scalability,integrability,reliability,and reproducibility of quantum devices and to save evaluation time,cost and energy.Here,we used a cryogenic on-chip multiplexer architecture and investigated the statistics of the 0.7 anomaly observed on the first three plateaus of the quantized conductance of semiconductor quantum point contact(QPC)transistors.Our single chips contain 256 split gate field-effect QPC transistors(QFET)each,with two 16-branch multiplexed source-drain and gate pads,allowing individual transistors to be selected,addressed and controlled through an electrostatic gate voltage process.A total of 1280 quantum transistors with nano-scale dimensions are patterned in 5 different chips of GaAs heterostructures.From the measurements of 571 functioning QFETs taken at temperatures T[1.4 K and T[40 mK,it is found that the spontaneous polarisation model and Kondo effect do not fit our results.Furthermore,some of the features in our data largely agreed with van Hove model with short-range interactions.Our approach provides further insight into the quantum mechanical properties and microscopic origin of the 0.7 anomaly in QFETs,paving the way for the development of semiconducting quantum circuits and integrated cryogenic electronics,for scalable quantum logic control,readout,synthesis,and processing applications. 展开更多
关键词 Cryogenic chip Cryogenic quantum multiplexer Semi-conductor quantum integrated circuit Quantumfield effect transistors Quantum point contacts Chip-scale cryogenic electronics
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Thermodynamic analysis of mixed and dry reforming of methane for solar thermal applications 被引量:4
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作者 Y. Sun T. ritchie +3 位作者 S. S. Hla S. McEvoy W. Stein J. H. Edwards 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2011年第6期568-576,共9页
Thermodynamic analysis of the reforming of methane with carbon dioxide alone ("dry reforming") and with carbon dioxide and steam together ("mixed reforming") is performed as part of a project which investigate... Thermodynamic analysis of the reforming of methane with carbon dioxide alone ("dry reforming") and with carbon dioxide and steam together ("mixed reforming") is performed as part of a project which investigates the suitability of these endothermic reactions for the storage of solar thermal energy. The Gibbs free energy minimization method was employed to identify thermodynamically optimal operating conditions for dry reforming as well as mixed reforming with a desired H2/CO molar ratio of 2. The non-stoichiometric equilibrium model was developed using FactSage software to conduct the thermodynamic calculations for carbon formation, H2/CO ratio, CH4 conversion and H2 yield as a function of reaction temperature, pressure and reactant molar ratios. Thermodynamic calculations demonstrate that in the mixed reforming process, optimal operating conditions in a carbon-free zone are under H2O/CH4 /CO2 =1.0/1.0/0.5, p = 1 to 10 bar and T = 800 to 850℃ for the production of syngas with a H2 /CO molar ratio of 2. Under the optimal conditions, the maximum H2 yield of 88.0% is achieved at 1 bar and 850℃ with a maximum CH4 conversion of 99.3%. In the dry reforming process, a carbon formation regime is always present at a CO2/CH4 molar ratio of 1 for T = 700 1000℃ and p = 1-30 bar, whereas a carbon-free regime can be obtained at a CO2/CH4 molar ratio greater than 1.5 and T≥800℃. 展开更多
关键词 mixed steam reforming of CH4 with CO2 CO2 reforming SYNGAS solar thermal application
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指导性集体锻炼对治疗中的早期乳腺癌妇女的益处:实用性随机对照试验 被引量:3
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作者 Nanette Mutrie Anna M Campbell +8 位作者 Fiona Whyte Alex McConnachie Carol Emslie Laura Lee Nora Kearney Andrew Walker Diana ritchie 方桦(译) 王燕(校) 《英国医学杂志中文版》 2007年第4期210-213,共4页
目的确定12周指导性集体锻炼对治疗中的早期乳腺癌患者在机体功能和心理上的获益,并随访6个月。设计实用性、前瞻性、随机对照、开放性试验。地点苏格兰3家国家医疗卫生服务体系肿瘤门诊和社区运动设施。参加者共203位妇女参加研究;其中... 目的确定12周指导性集体锻炼对治疗中的早期乳腺癌患者在机体功能和心理上的获益,并随访6个月。设计实用性、前瞻性、随机对照、开放性试验。地点苏格兰3家国家医疗卫生服务体系肿瘤门诊和社区运动设施。参加者共203位妇女参加研究;其中177位完成6个月随访。干预与常规护理相对照,干预组予12周指导性集体锻炼加常规护理。主要结果评价癌症治疗功能评价(FACT)问卷、贝克抑郁问卷、正性和负性情绪量表、体重指数、7日体力活动回忆问卷、12分钟步行实验和肩关节活动度评估。结果对基线值、研究中心、基线治疗和参加干预试验时的年龄进行校正后,综合效应模型的评估结果(干预组减对照组)显示第12周时:12分钟步行距离为129米(95%可信区间83~176),1周的中等强度活动时间182分钟(75~289),肩关节活动度2.6(1.6~3.7),乳腺癌特定的生活质量量表2.5(1.0~3.9),正性情绪4.0(1.8~6.3)。初步结果未发现干预锻炼对生活质量综合量表(FACT-G)有影响。随访6个月后,大多数效果维持不变,并且在乳腺癌特定的生活质量上得到改善。尚未有不良反应的报道。结论在12周干预锻炼结束时以及6个月后,指导性集体锻炼均显示出机体功能和心理上的获益。因此临床医生应该鼓励患者活动,决策者们应该考虑把体育锻炼纳入到癌症康复服务中来。试验注册号当前对照试验 ISRCTN12587864[controlled-trial.com]。 展开更多
关键词 随机对照试验 早期乳腺癌 体育锻炼 治疗功能 集体 妇女 生活质量量表 医疗卫生服务体系
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Pancreatic cancer serum biomarker PC-594:Diagnostic performance and comparison to CA19-9 被引量:3
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作者 Shawn A ritchie Bassirou Chitou +4 位作者 Qingan Zheng Dushmanthi Jayasinghe Wei Jin Asuka Mochizuki Dayan B Goodenowe 《World Journal of Gastroenterology》 SCIE CAS 2015年第21期6604-6612,共9页
AIM:To investigate serum PC-594 fatty acid levels as a potential biomarker in North American pancreatic cancer(PaC) patients,and to compare its performance to CA19-9.METHODS:Using tandem mass spectrometry,we evaluated... AIM:To investigate serum PC-594 fatty acid levels as a potential biomarker in North American pancreatic cancer(PaC) patients,and to compare its performance to CA19-9.METHODS:Using tandem mass spectrometry,we evaluated serum PC-594 levels from 84 North American patients with confirmed PaC and 99 cancer-free control subjects.We determined CA19-9 levels by ELISA.Significance between Pa C patients and controls,and association with clinical variables was determined by analysis of variance and t-tests.Diagnostic performance was evaluated by receiver-operator characteristic(ROC)curve analysis,and PC-594 correlation with age and CA19-9 determined by regression analysis.RESULTS:Mean PC-594 levels were 3.7 times lower in Pa C patients compared to controls(P < 0.0001).The mean level in PaC patient serum was 0.76 ± 0.07 μmol/L,and the mean level in control subjects was 2.79 ± 0.15 μmol/L.There was no correlation between PC-594 and age,disease stage or gender(P > 0.05).Using 1.25 μmol/L as a PC-594 threshold produced a relative risk(RR) of 9.4(P < 0.0001,95%CI:5.0-17.7).The area under the receiver-operator characteristic curve(ROCAUC) was 0.93(95%CI:0.91-0.95) for PC-594 and 0.85(95%CI:0.82-0.88) for CA19-9.Sensitivity at 90% specificity was 87% for PC-594 and 71% for CA19-9.Six Pa C patients with CA19-9 above 35 U/m L showed normal PC-594 levels,while 24 Pa C patients with normal CA19-9 showed low PC-594 levels.Eighty-five of the 99 control subjects(86%) showed normal levels of both markers.CONCLUSION:PC-594 biomarker levels are significantly reduced in North American Pa C patients,and showed superior diagnostic performance compared to CA19-9. 展开更多
关键词 PANCREATIC cancer Risk Screening Blood FATTY acid Biomarker METABOLITE PC-594
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Graphene-loaded metal wire grating for deep and broadband THz modulation in total internal reflection geometry 被引量:2
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作者 YIWEN SUN RICCARDO DEGLJINNOCENTI +9 位作者 DAVID A.ritchie HARVEY E.BEERE LONG XIAO MICHAEL RUGGIERO J.AXEL ZEITLER RAYKO I.STANTCHEV DANNI CHEN ZHENGCHUN PENG EMMA MACPHERSON XUDONG LIU 《Photonics Research》 SCIE EI 2018年第12期1151-1157,共7页
We employed a metallic wire grating loaded with graphene and operating in total internal reflection (TIR) geometry to realize deep and broadband THz modulation. The non-resonant field enhancement effect of the evanesc... We employed a metallic wire grating loaded with graphene and operating in total internal reflection (TIR) geometry to realize deep and broadband THz modulation. The non-resonant field enhancement effect of the evanescent wave in TIR geometry and in the subwavelength wire grating was combined to demonstrate a ~77% modulation depth (MD) in the frequency range of 0.2–1.4 THz. This MD, achieved electrically with a SiO_2∕Si gated graphene device, was 4.5 times higher than that of the device without a metal grating in transmission geometry. By optimizing the parameters of the metallic wire grating, the required sheet conductivity of graphene for deep modulation was lowered to 0.87 mS. This work has potential applications in THz communication and real-time THz imaging. 展开更多
关键词 MODULATION depth (MD) GRAPHENE Wire GRATING
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Demonising the dingo: How much wild dogma is enough? 被引量:2
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作者 Mike LETNIC Mathew S. CROWTHER +1 位作者 Christopher R. DICKMAN Euan G. ritchie 《Current Zoology》 SCIE CAS CSCD 北大核心 2011年第5期668-670,共3页
The roles that top predators play in regulating the structure and function of ecosystems have long been controversial. This is particularly the case when predators pose adverse risks for human life and/or economic int... The roles that top predators play in regulating the structure and function of ecosystems have long been controversial. This is particularly the case when predators pose adverse risks for human life and/or economic interests. The critique of literature on dingoes and their ecological roles in Australia provided by Allen et al. (2011) shows that top predators remain a potentially polarising issue. In opposition to Allen et al. we argue that these widespread patterns of species' abundances, attributed to the ef- fects of dingoes and evident at scales ranging from the foraging behaviour of individuals through to continental scale patterns of species abundances, constitute strong support for the mesopredator release hypothesis and provide evidence that dingoes benefit biodiversity conservation by inducing community wide trophic cascades. Harnessing the positive ecological effects of dingoes while at the same time minimising their impacts on agriculture is a major socio-political challenge in Australia [Current Zoology 57 (5): 668-670]. 展开更多
关键词 Trophic cascade Mesopredator release hypothesis DINGO FOX Intra-guild predation
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Frequency-tunable continuous-wave random lasers at terahertz frequencies 被引量:2
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作者 Simone Biasco Harvey E.Beere +4 位作者 David A.ritchie Lianhe Li AGiles Davies Edmund H.Linfield Miriam S.Vitiello 《Light(Science & Applications)》 SCIE EI CAS CSCD 2019年第1期828-840,共13页
Random lasers are a class of devices in which feedback arises from multiple elastic scattering in a highly disordered structure,providing an almost ideal light source for artefact-free imaging due to achievable low sp... Random lasers are a class of devices in which feedback arises from multiple elastic scattering in a highly disordered structure,providing an almost ideal light source for artefact-free imaging due to achievable low spatial coherence.However,for many applications ranging from sensing and spectroscopy to speckle-free imaging,it is essential to have high-radiance sources operating in continuous-wave(CW).In this paper,we demonstrate CW operation of a random laser using an electrically pumped quantum-cascade laser gain medium in which a bi-dimensional(2D)random distribution of air holes is patterned into the top metal waveguide.We obtain a highly collimated vertical emission at ~3 THz,with a 430 GHz bandwidth,device operation up to 110 K,peak(pulsed)power of 21 mW,and CW emission of 1.7 mW.Furthermore,we show that an external cavity formed with a movable mirror can be used to tune a random laser,obtaining continuous frequency tuning over 11 GHz. 展开更多
关键词 TUNABLE tuning PUMPED
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High day and night temperatures impact on cotton yield and quality——current status and future research direction
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作者 SAINI Dinesh K. IMPA S.M. +5 位作者 MCCALLISTER Donna PATIL Gunvant B. ABIDI Noureddine ritchie Glen JACONIS S.Y. JAGADISH Krishna S.V. 《Journal of Cotton Research》 CAS 2023年第3期209-225,共17页
Heat waves,and an increased number of warm days and nights,have become more prevalent in major agricultural regions of the world.Although well adapted to semi-arid regions,cotton is vulnerable to high temperatures,par... Heat waves,and an increased number of warm days and nights,have become more prevalent in major agricultural regions of the world.Although well adapted to semi-arid regions,cotton is vulnerable to high temperatures,particularly during flowering and boll development.To maintain lint yield potential without compromising its quality under high-temperature stress,it is essential to understand the effects of heat stress on various stages of plant growth and development,and associated tolerance mechanisms.Despite ongoing efforts to gather data on the effects of heat stress on cotton growth and development,there remains a critical gap in understanding the distinct influence of high temperatures during the day and night on cotton yield and quality.Also,identifying mechanisms and target traits that induce greater high day and night temperature tolerance is essential for breeding climate-resilient cotton for future uncertain climates.To bridge these knowledge gaps,we embarked on a rigorous and comprehensive review of published literature,delving into the impact of heat stress on cotton yields and the consequential losses in fiber quality.This review encompasses information on the effects of heat stress on growth,physiological,and biochemical responses,fertilization,cotton yield,and quality.Additionally,we discuss management options for minimizing heat stress-induced damage,and the benefits of integrating conventional and genomics-assisted breeding for developing heat-tolerant cotton cultivars.Finally,future research areas that need to be addressed to develop heat-resilient cotton are proposed. 展开更多
关键词 Controlled environment COTTON Fiber yield and quality Heat stress Heat tents Reproductive failure
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Cotton Physiological Parameters Affected by Episodic Irrigation Interruption 被引量:1
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作者 Fulvio Rodriguez Simao Glen Lorin ritchie Craig William Bednarz 《Journal of Agricultural Science and Technology(A)》 2013年第6期443-454,共12页
Improving cotton irrigation management practices in West Texas is important for increasing farmers' profits and for sustainability of the Ogallala aquifer. The objective of this work was to evaluate the effects in fi... Improving cotton irrigation management practices in West Texas is important for increasing farmers' profits and for sustainability of the Ogallala aquifer. The objective of this work was to evaluate the effects in field controlled episodic drought conditions on cotton gas exchange. Irrigated cotton was subjected to water stress at different timings. Irrigation was interrupted at the squaring stage, early flowering stage, from three weeks at peak bloom, and from peak bloom to the crop termination. These episodic drought treatments were compared with cotton fully irrigated throughout the whole season. From 2010 to 2012, cotton cultivar FM9180 gas exchange was measured throughout the season using a LiCor-6400 portable photosynthesis system. In 2011 and 2012, measurements were also made on DP0935 cultivar. The cotton physiological parameters evaluated included photosynthesis, transpiration and temperature. From the several parameters evaluated, some relationships were presented. Episodic drought periods can affect leaf-level gas exchange and impact yield. Photosynthesis and yield were particularly sensitive to water deficit at early flowering. Despite an increase in leaf water use efficiency under water deficit, overall growth and yield were inhibited in all treatments with a stress component. Understanding the relative sensitivity at different growth stages can help with irrigation decisions when water resources are limited. 展开更多
关键词 Cotton physiology Gossypium hirsutum L. water stress gas exchange photosynthesis.
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Irrigation's effect and applied selection on the fiber quality of Ethyl MethaneSulfonate(EMS)treated upland cotton(Gossypium hirsutum L.) 被引量:1
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作者 WITT Travis W ULLOA Mauricio +2 位作者 PELLETIER Mathew G. MENDU Venugopal ritchie Glen L. 《Journal of Cotton Research》 2018年第4期1-11,共11页
Background: Producing rainfed cotton(Gossypium hirsutum L.) with high fiber quality has been challenging in the Texas High Plains because of extended periods of insufficient rainfall during sensitive boll developmenta... Background: Producing rainfed cotton(Gossypium hirsutum L.) with high fiber quality has been challenging in the Texas High Plains because of extended periods of insufficient rainfall during sensitive boll developmental stages.Genetic variation created by Ethyl MethaneSulfonate(EMS) mutagen has successfully improved fiber quality of cotton. However, little is known about the effect of water deficit environments on fiber quality. Three EMS treated populations were advanced from the first to the fourth generation(M1 to M4) as bulk harvested populations. In2014, single-plant divergent selection was applied based on perceived morphological and agronomic differences seen during and at the end of the season.Results: Analyses from these selections in 2014-2016 showed significant(P< 0.05) improvement between and within populations for fiber traits(micronaire, length, strength, uniformity, and elongation) when compared with the original non-treated EMS source; some selections were found to have excellent fiber quality under diverse irrigationregimes.Conclusions: Some of these selections are being considered for germplasm release and could be useful for improving the fiber quality of cotton under water limited conditions, thereby helping to ensure the long-term survival of the cotton industry on the Texas High Plains. 展开更多
关键词 BREEDING DROUGHT EMS Ethyl MethaneSulfonate Fiber quality SELECTION
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Myosin VI.II Regulates Protonemal Patterning and Developmental Timing in the Moss Physcomitrella patens 被引量:1
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作者 Shu-Zon Wu Julie A. ritchie +2 位作者 Ai-Hong Pan Ralph S. Quatrano Magdalena Bezanilla 《Molecular Plant》 SCIE CAS CSCD 2011年第5期909-921,共13页
Plants have two classes of myosins. While recent work has focused on class XI myosins showing that myosin XI is responsible for organelle motility and cytoplasmic streaming, much less is known about the role of myosin... Plants have two classes of myosins. While recent work has focused on class XI myosins showing that myosin XI is responsible for organelle motility and cytoplasmic streaming, much less is known about the role of myosin VIII in plant growth and development. We have used a combination of RNAi and insertional knockouts to probe myosin VIII function in the moss Physcomitrella patens. We isolated Amyo8ABCDE plants demonstrating that myosin VIII is not required for plant viability. However, myosin VIII mutants are smaller than wild-type plants in part due to a defect in cell size. Additionally, Amyo8ABCDE plants produce more side branches and form gametophores much earlier than wild-type plants. In the ab- sence of nutrient media, Amyo8ABCDE plants exhibit significant protonemal patterning defects, including highly curved protonemal filaments, morphologically defective side branches, as well as an increase in the number of branches. Exogenous auxin partially rescues protonemal defects in Amyo8ABCDE plants grown in the absence of nutrients. This result, together with defects in protonemal branching, smaller caulonemal ceils, and accelerated development in the Amyo8ABCDE plants, suggests that myosin VIII is involved in hormone homeostasis in P patens. 展开更多
关键词 Cell division cell expansion cell morphogenesis CYTOSKELETON development.
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