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细胞无性系变异及其在植物育种体上的应用

生物技术通报 1989年第5期5卷 1-5页

作者： david a.evans 陈志贤王娇娟

科学家们对生长在培养基上的植物细胞产生广泛的遗传变异的发现已有若干年了。早期的一些报道记述了细胞的多倍性、非整倍性、细胞分裂后期桥,以及片段和染色体的稳定性。过去几年的研究观察大体上已得出一个结论:长期生长在培养基上的... 详细信息

科学家们对生长在培养基上的植物细胞产生广泛的遗传变异的发现已有若干年了。早期的一些报道记述了细胞的多倍性、非整倍性、细胞分裂后期桥,以及片段和染色体的稳定性。过去几年的研究观察大体上已得出一个结论:长期生长在培养基上的植株细胞遗传是不稳定的,通常会失去再生植株的能力。

关键词：无性系植物育种非整倍性遗传变异多倍性分裂后期有丝分裂交换染色体结构突变体减数分裂

Palladium-catalyzed S_(N)2 glycosylation of phenols

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Science China Chemistry 2024年第4期67卷 1037-1038页

作者： Yu Zhu P.Andrew evans Department of Chemistry Queen’s University90 Bader LaneKingstonK7L 3N6Canada Xiangya School of Pharmaceutical Sciences Central South UniversityChangsha 410013China

Glycosides are essential structural motifs present in an array of important medicines,materials,and natural products[1].Nevertheless,the chemo-and stereoselective construction of the glycosidic linkage is a long-standing challenge because relatively minor variations in the glycosyl donor or acceptor’s structure can impact stereoselectivity,thus influencing the product's functional properties.

关键词： properties Palladium catalyzed

Enantioselective iridium-catalyzed allylic substitution with a Reformatsky reagent: direct construction of β-stereogenic homoallylic esters

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Science China Chemistry 2024年第11期67卷 3791-3797页

作者： Debasis Pal Kirana D.Veeranna Yuk Fai Wong P.Andrew evans Department of Chemistry Queen's University Xiangya School of Pharmaceutical Sciences Central South University

The Reformatsky reagent derived from ethyl bromoacetate circumvents the challenge associated with the direct regio-and enantioselective iridium-catalyzed allylic alkylation with an unstabilized aliphatic ester enolate. Notably, this work represents the first example of using a Reformatsky reagent in a metal-allyl reaction, which permits the direct construction of enantioenriched β-stereogenic homoallylic esters without preactivation of the pronucleophile or post-reaction modification of the product(e.g., thermal decarboxylation of a 1,3-dicarbonyl). Moreover, the process allows the coupling of a broad range of sterically and electronically diverse electrophiles bearing aryl, heteroaryl and alkenyl derivatives, including the significantly more challenging alkyl-substituted allylic carbonates. The versatility of the ester product is exemplified by a series of functional group manipulations and the development of a concise and efficient enantioselective total synthesis of the natural product,(+)-descurainolide A. Finally, mechanistic studies indicate that the zinc enolate behaves as a soft nucleophile that undergoes outer-sphere alkylation.

关键词： allylic substitution asymmetric catalysis mechanistic studies natural product synthesis Reformatsky reagent

Identification of earthquake induced structural damage based on synchroextracting transform

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Earthquake Engineering and Engineering Vibration 2024年第2期23卷 475-487页

作者： Roshan Kumar Gaurav Kumar Wei Zhao Arvind R Yadav Gang Yu Jayendra Kumar evans Amponsah Department of Electronic and Information Technology Miami College of Henan UniversityHenan 475004China Alliance University Alliance College of Engineering and DesignBanglore 562106India Department of Electronics and Comm Parul UniversityVadodra 391760India School of Electrical Engineering University of JinanJinan 250022China Department of Electronics and Comm NIT JamshedpurJamshedpur 831014India Department of Civil engineering Kwame Nkrumah University of Science and TechnologyKumasi 10959Ghana

Several popular time-frequency techniques,including the Wigner-Ville distribution,smoothed pseudo-Wigner-Ville distribution,wavelet transform,synchrosqueezing transform,Hilbert-Huang transform,and Gabor-Wigner transform,are investigated to determine how well they can identify damage to *** this work,a synchroextracting transform(SET)based on the short-time Fourier transform is proposed for estimating post-earthquake structural *** performance of SET for artificially generated signals and actual earthquake signals is examined with existing *** other tested techniques,SET improves frequency resolution to a great extent by lowering the influence of smearing along the time-frequency ***,interpretation and readability with the proposed method are improved,and small changes in the time-varying frequency characteristics of the damaged buildings are easily detected through the SET method.

关键词： cross-term damage detection earthquake signal synchroextracting transform time-frequency

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Equal Opportunities

英语世界 2024年第4期 126-128页

作者： Russell evans

Pre-reading task Youaregoingtoreadanarticleabout ***,thinkaboutyourown *** equal opportunities policy? Why? Which groups of people do you think have been helped by equal opportunities law?

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Efficacy of nonsolvent flower pollen extracts in healthy women with urinary incontinence:A randomized,double-blind,placebo-controlled,parallel study

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Current Urology 2024年第3期18卷 203-211页

作者： Marc Moulin Erin D.Lewis david C.Crowley Colleen E.May Malkanthi evans KGK Science Inc. LondonOntarioCanada Graminex L.L.C.SaginawMIUSA

Background Urinary incontinence(UI)is a debilitating and common condition that adversely affects quality of *** and surgical approaches for managing UI symptoms may result in undesirable risks and *** randomized,double-blind,placebo-controlled,parallel study investigated the efficacy of 2 nonsolvent flower pollen extracts on UI in healthy *** and methods One-hundred and fourteen women aged 40–75 years who scored≥5 on the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form(ICIQ-SF)were randomized to receive either Graminex®RCT Fem™UI,Graminex®PollenBerry®,or placebo for 24 *** primary outcome was the change in the ICIQ-SF score between the trial and placebo groups after 24 weeks of *** secondary outcomes included changes in the frequency of nocturia(recorded in 3-day void diaries)and 24-hour leakage volume(assessed via pad weight)after 6,12,18,and 24 weeks of supplementation and changes in stress-induced urinary leakage volume(after completion of a provocative maneuver challenge)after 24 weeks of *** All the groups demonstrated improvement in ICIQ-SF scores at week 24(p<0.001).The RCT Fem™UI group had the greatest improvement in ICIQ-SF scores(−4.07±3.4),followed by the PollenBerry®group(−3.34±2.87)and placebo group(−2.61±3.52).The RCT Fem™UI group had corresponding improvements in 24-hour leakage volume(−17.68±39.84 g)and frequency of nocturia(−0.52±1.26)(p≤0.05).PollenBerry®supplementation significantly improved stress-induced urinary leakage volume(−7.12±15.64 g)at week *** study products demonstrated safe hematological and chemical *** RCT Fem™UI supplementation resulted in significant and clinically meaningful reductions in UI severity,with corresponding improvements in daily urinary leakage volume and frequency of ***®significantly improved stress-induced urinary leakage volume,suggesting that it may be eff

关键词： Urinary incontinence Pollen extract Healthy women Dietary supplement ICIQ-SF Urinary leakage

数字化能源管理系统促进工业界节能减碳的分析与建议

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中国科学院院刊 2024年第2期39卷 311-322页

作者：耿端阳许通朱庆华 Steve evans 英国剑桥大学工程系制造研究所剑桥CB30FS 英国剑桥大学土地经济系环境能源与自然资源管理中心剑桥CB33QZ 上海交通大学安泰经济与管理学院上海200030

工业生产是碳排放的主要来源。减少能源浪费、达成生产节能对实现我国“双碳”目标至关重要。随着数字化技术进步,数字化能源管理系统可通过将不可见的能源可视化,促进企业节能。文章分析了英国、美国、德国、日本和瑞典应用能源管理系... 详细信息

工业生产是碳排放的主要来源。减少能源浪费、达成生产节能对实现我国“双碳”目标至关重要。随着数字化技术进步,数字化能源管理系统可通过将不可见的能源可视化,促进企业节能。文章分析了英国、美国、德国、日本和瑞典应用能源管理系统的现状,总结了其特点与应用条件,与我国在此方面的发展进行了对比,并探讨了我国在部署能源管理系统过程中所面临的挑战。文章还提出从“工厂、产线和设备”到“产品”角度分析能耗,构建“基于生产步骤的单位产品能耗标签”的方法论框架。探讨了政府、企业等利益相关者在该方法论中的角色,并提出了政府支持发展数字化能源管理系统的对策,包括推动系统建设、支持合作、确定能耗基准和引导企业对标行业最优实践。

关键词：数字化技术能源浪费能源管理能源系统碳中和

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Giving Food a Fiber Boost: Adding High Beta-Glucan Ingredient from Barley to Everyday Foods

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Food and Nutrition Sciences 2024年第4期15卷 277-289页

作者： Gongshe Hu Sherry Ellberg Kathy Satterfield Chris evans USDA ARS Pacific West Area 1691 S. 2700 W Aberdeen Idaho USA

Lack of dietary fiber contributes to many health issues, particularly chronic vascular diseases. Mixed linkage β-1.3 - 1.4 beta-glucan (beta-glucan, in this paper) is a confirmed beneficial ingredient for the human diet through reduction of cholesterol and the glycemic index. Barley contains the highest beta-glucan content of all the grains, and in this study, a percentage of flour from two high beta glucan lines was, each, added to an array of wheat-based food products to measure how it impacted total dietary fiber. Results showed that beta-glucan content was higher in all the products containing the added high beta-glucan flour, along with increased total dietary fiber content. Protein content in the food products is also increased with the higher protein in the barley flours added. Beta-glucan content in the barley-added products increased to 1.2% - 4.0% versus 0.2% - 0.5% in the pure wheat products, while the dietary fibers increased to 3.5% - 24.4% versus 2.1% - 9.1% in pure wheat product controls. This research provided experimental evidence that using a high beta-glucan barley ingredient in food can increase dietary fiber to benefit health.

关键词： Food High Fiber Barley Ingredient Beta-Glucan Human Health

Dark Matter Density Profiles of Selected Spiral Galaxies

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International Journal of Astronomy and Astrophysics 2024年第3期14卷 172-183页

作者： Alberto Sadun Brittany Salmon Conor evans Masoud Asadi-Zeydabadi Department of Physics University of Colorado Denver Denver USA

Understanding the dark matter distribution throughout a galaxy can provide insight into its elusive nature. Numerous density profiles, such as the Navarro, Frenk and White model, have been created in an attempt to study this distribution through analyzing orbital velocities of luminous matter and modeling dark matter distributions to explain these observations. However, we are interested in a simple model to consider the significant fluctuations in rotation curves at larger radii. Therefore, our model is much simpler compared to those previously mentioned. Our model used all the observational data available for four selected galactic rotation curves. These data present a significant variation in the orbital velocity of matter at the same distances. By running real observational data through our model, we show that the density of the dark matter within them shows real complex structure, which is not suggested by other computational models. Our aim of this paper is to model this structure and then speculate as to the cause and implications of these density fluctuations.

关键词： Dark Matter Density Galactic Rotation Curves Spiral Galaxies NGC 2841 NGC 4527 NGC 4945 NGC 3198