检索结果-南通市图书馆

A mutation in the promoter of the yellow stripe-like transporter gene in cucumber results in a yellow cotyledon phenotype

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2024年第3期23卷 849-862页

作者： jiawei Pan jia Song Rahat Sharif xuewen xu Shutong Li xuehao Chen School of Horticulture and Landscape Architecture Yangzhou UniversityYangzhou 225009China Institute of Vegetables Tianjin Academy of Agricultural SciencesTianjin 300384China

Leaf color mutants in higher plants are considered to be ideal materials for studying the chlorophyll biosynthesis,photosynthesis mechanism and chloroplast development.Herein,we identified a spontaneous mutant,yc412,in cultivated cucumber that exhibited yellow cotyledons.The yellow-lethal mutant was diagnosed with an abnormal chloroplast ultrastructure,and reduced photosynthetic capacity and pigment content.Through bulked segregant analysis-based whole-genome sequencing and fine genetic mapping,we narrowed the yellow cotyledons (yc) locus to a 96.8 kb interval on chromosome 3.By resequencing and molecular cloning,we showed that Csyc is a potential candidate gene,which encodes a yellow stripe-like (YSL) transporter.The T to C mutation in the promoter region of Csyc caused the yellow cotyledon phenotype in yc412.Compared to YZU027A (WT),the expression of Csyc was significantly downregulated in the cotyledons of yc412.Silencing of Csyc in cucumber via virus-induced gene silencing resulted in chlorotic leaves,mainly by suppressing the chlorophyll content.Furthermore,a comparative transcriptome analysis revealed that chloroplast-related genes and chlorophyll biosynthesis genes were significantly downregulated in yc412 cotyledons.Our results provide new insights into the molecular function of the YSL transporter in plant chloroplast development and chlorophyll synthesis.

关键词： cucumber yellow-lethal cotyledons chloroplast development yellow stripe-like transporter

Influence of topography on the fine structures of stratospheric gravity waves:An analysis using COSMIC-2 temperature data

在线全文

学校读者我要写书评

暂无评论

Earth and Planetary Physics 2024年第3期8卷 497-513页

作者： jiaRui Wei Xiao Liu JiYao xu QinZeng Li hong Gao State Key Laboratory of Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Institute of Electromagnetic Wave School of PhysicsHenan Normal UniversityXinxiang Henan 453000China

We derive the potential energy of gravity waves(GWs)in the upper troposphere and stratosphere at 45°S-45°N from December 2019 to November 2022 by using temperature profiles retrieved from the Constellation Observing System for Meteorology,Ionosphere,and Climate-2(COSMIC-2)satellite.Owing to the dense sampling of COSMIC-2,in addition to the strong peaks of gravity wave potential energy(GWPE)above the Andes and Tibetan Plateau,we found weak peaks above the Rocky,Atlas,Caucasus,and Tianshan Mountains.The land-sea contrast is responsible for the longitudinal variations of the GWPE in the lower and upper stratosphere.At 40°N/S,the peaks were mainly above the topographic regions during the winter.At 20°N/S,the peaks were a slight distance away from the topographic regions and might be the combined effect of nontopographic GWs and mountain waves.Near the Equator,the peaks were mainly above the regions with the lowest sea level altitude and may have resulted from convection.Our results indicate that even above the local regions with lower sea level altitudes compared with the Andes and Tibetan Plateau,the GWPE also exhibits fine structures in geographic distributions.We found that dissipation layers above the tropopause jet provide the body force to generate secondary waves in the upper stratosphere,especially during the winter months of each hemisphere and at latitudes of greater than 20°N/S.

关键词： topography fine structures stratospheric gravity waves Constellation Observing System for Meteorology Ionosphere and Climate-2(COSMIC-2) dissipation layers

Effects of Different Raw Materials and Additions on Wave Transparency of Alumina Fiber Products

在线全文

学校读者我要写书评

暂无评论

China's Refractories 2024年第1期33卷 40-43页

作者： WANG jia SUN Xiaofei xu jianfeng xu Peipei Sinosteel Luoyang Institute of Refractories Research Co. Ltd.Luoyang 471039China

Fiber products for microwave kilns were prepared using alumina fibers with alumina contents of 72 mass%and 80 mass%,and calcined alumina powder(4-6μm)as the main raw materials,silica sol as the binder,and cationic starch as the flocculant.Effects of different raw materials and their additions on the wave transparency of fiber products were researched.The results show that as the alumina fiber(72%)addition increases,the heating rate of the samples first decreases and then increases,and the corresponding wave transparency of the sample first increases and then decreases.When the alumina fibers addition is 40 mass%and the alumina powder addition is 30 mass%,the prepared microwave kiln lining material has a higher mullite content,which improves the wave transparency of the sample.The sample prepared from alumina fibers with an alumina content of 80%has a suitable glass-mullite phase ratio,performs lower overall dielectric constant and good wave transparency,and is a suitable lining material for microwave kilns.

关键词： alumina fibers microwave kiln wave transparency

Analysis of factors impacting postoperative pain and quality of life in patients with mixed hemorrhoids:A retrospective study

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastrointestinal Surgery 2024年第3期16卷 731-739页

作者： Xiao-Wen Sun Jing-Yi xu Chang-Zhen Zhu Si-jia Li Lu-jia Jin Zhi-Dong Zhu Department of Gastrointestinal Surgery Tsinghua University Affiliated Beijing Tsinghua Changgeng HospitalBeijing 102218China Surgical Department Tsinghua University Affiliated Beijing Tsinghua Changgeng HospitalBeijing 102218China

BACKGROUND Hemorrhoids are among the most common and frequently encountered chronic anorectal diseases in anorectal surgery.They are venous clusters formed by con-gestion,expansion,and flexion of the venous plexus in the lower part of the rec-tum.Mixed hemorrhoids bleed easily and recurrently,and this can result in severe anemia.Hence,they may have a negative effect on the health of the patient and surgical treatment is required.Milligan-Morgan hemorrhoidectomy has been widely used since 1937 for the treatment of grade III and IV hemorrhoids.How-ever,most patients experience different degrees of postoperative pain that may cause anxiety.with mixed hemorrhoids post-surgery.METHODS The clinical data of patients with mixed hemorrhoids who underwent Milligan-Morgan hemorrhoidectomy were collected retrospectively.The basic character-istics of the enrolled patients with mixed hemorrhoids were recorded,and based on the Goligher clinical grading system,the hemorrhoids were classified as grades III or IV.The endpoint of this study was the disappearance of pain in all patients.Quantitative data were presented as mean±SD,such as age,pain score,and QoL score.Student’s t-test was used to compare the groups.RESULTS A total of 164 patients were enrolled.The distribution of the visual analog scale pain scores of all patients at 3,7,14 and 28 d after surgery showed that post-surgery pain was significantly reduced with the passage of time.Fourteen days after the operation,the pain had completely disappeared in some patients.Twenty-eight days after the surgery,none of the patients experienced any pain.Comparing the World Health Or-ganization Quality of Life-BREF self-reporting questionnaire scores of patients between 14 and 28 d after surgery,we observed that the quality-of-life scores of the patients post-surgery had significantly improved.There were six items that were compared at 14-and 28-d post-surgery.The mean QoL score 28 d after surgery(4.79±0.46)was higher than that at 14 d post-surgery(3.79±0.57).The mean health condition

关键词： Hemorrhoids Mixed hemorrhoids Milligan organ hemorrhoidectomy Postoperative pain Quality of life Anesthesia mode

Bayesian inference of neutron-skin thickness and neutron-star observables based on effective nuclear interactions

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2024年

作者： jia Zhou Jun xu Shanghai Institute of Applied Physics Chinese Academy of Sciences University of Chinese Academy of Sciences School of Physics Science and Engineering Tongji University

We have obtained the constraints on the density dependence of the symmetry energy from neutron-skin thickness data by parityviolating electron scatterings and neutron-star observables using a Bayesian approach, based on the standard Skyrme-HartreeFock(SHF) model and its extension as well as the relativistic mean-field(RMF) model. While the neutron-skin thickness data(neutron-star observables) mostly constrain the symmetry energy at subsaturation(suprasaturation) densities, they may more or less constrain the behavior of the symmetry energy at suprasaturation(subsaturation) densities, depending on the energy-density functional form. Besides showing the final posterior density dependence of the symmetry energy, we also compare the slope parameters of the symmetry energy at 0.10 fm-3as well as the values of the symmetry energy at twice saturation density from three effective nuclear interactions. The present work serves as a comparison study based on relativistic and non-relativistic energy-density functionals, for constraining the nuclear symmetry energy from low to high densities using a Bayesian approach.

关键词：

Ferroelectric BaTiO_(3) /Pr_(2)O_(3) heterojunction harvesting roomtemperature cold–hot alternation energy for efficiently pyrocatalytic dye decomposition

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Advanced Ceramics 2024年第1期13卷 44-52页

作者： Zheng Wu Taosheng xu Luohong Zhang Tingting Liu Zhansheng Wu Gangqiang Zhu Yanmin jia School of Environmental and Chemical Engineering Xi’an Key Laboratory of Textile Chemical Engineering AuxiliariesXi’an Polytechnic UniversityXi’an 710048China School of Physics and Information Technology Shaanxi Normal UniversityXi’an 710062China

The strong pyrocatalytic dye decomposition of the BaTiO_(3)/Pr_(2)O_(3) heterojunction catalyst under cold–hot alternation conditions has been demonstrated in this work.For pure BaTiO_(3) nanofibers,~54%rhodamine B(RhB)dye is decomposed under the cold–hot alternation of 29–57℃.With the loading content of Pr_(2)O_(3) increases from 0 to 4 wt%,the pyrocatalytic decomposition ratio of RhB solution increases first and then decreases,eventually achieving a maximum of 91%at 3 wt%.The enhanced pyrocatalytic performance after loading Pr_(2)O_(3) can be attributed to an internal electric field of the heterojunction,which effectively separates positive and negative charges.The strongly pyrocatalytic performance of BaTiO_(3)/Pr_(2)O_(3) makes it hopeful for applications in the dye wastewater treatment through harvesting the environmental cold–hot temperature alternation thermal energy in future.

关键词： pyroelectric materials BaTiO_(3) pyrocatalysis BaTiO_(3)/Pr_(2)O_(3)heterojunction dye decomposition

Catalytic asymmetric dearomative azo-Diels–Alder reaction of 2-vinlyindoles

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第4期35卷 357-362页

作者： Yu-Hang Miao Zheng-xu Zhang xu-Yi Huang Yuan-Zhao Hua Shi-Kun jia Xiao Xiao Min-Can Wang Li-Ping xu Guang-jian Mei Green Catalysis Center and College of ChemistryZhengzhou UniversityZhengzhou 450052China School of Chemistry and Chemical Engineering Shandong University of TechnologyZibo 255000China Institute of Pharmaceutical Science and Technology Zhejiang University of TechnologyHangzhou 310014China

Due to the high electrophilic nature of azo-dienophiles, azo-Diels–Alder proceeds rapidly even without the need of a catalyst and is therefore regarded as the “click reaction”. This spontaneity causes strong background reaction and poses a daunting challenge to chemists for developing the catalytic asymmetric version. Reported herein is the first catalytic asymmetric dearomative azo-Diels–Alder reaction between2-vinylindoles and triazoledione. This protocol makes use of the high energy barrier of dearomatization to avert the strong background reaction of azo-Diels–Alder reaction, allowing the implementation of the projected reaction at ambient temperature. Density functional theory calculations have been performed to gain insights into the reaction mechanism and the origins of the enantioselectivity. By using this method,a variety of tetracyclic indole derivatives have been readily prepared in good to excellent yields and with excellent diastereo-and enantio–selectivities(33 examples, up to 97% yield and >99% ee, >20:1 dr).

关键词： Catalytic asymmetric dearomatization Azo-Diels–Alder reaction 2-Vinylindoles Chiral phosphoric acid Tetracyclic indole derivatives

Variability of urban fractional vegetation cover and its driving factors in 328 cities in China

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第2期67卷 466-482页

作者： Fei FENG Xin YANG Baoquan jia Xiaoting LI Xianwen LI Chengyang xu Kaicun WANG Research Centre of Urban Forestry Key Laboratory for Silviculture and Forest Ecosystem of State Forestry and Grassland AdministrationBeijing Forestry UniversityBeijing100083China State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing100875China Research Institute of Forestry Chinese Academy of ForestryBeijing100091China School of Architecture Tsinghua UniversityBeijing100084China College of Urban and Environmental Sciences Sino-French Institute for Earth System ScienceInstitute of Carbon NeutralityPeking UniversityBeijing100871China

Urban green space promotes the health of urban residents,enhances urban ecosystem biodiversity,mitigates environmental pollution,and attenuates urban heat island effect.However,urban vegetation cover is highly heterogeneous and difficult to quantify.In this study,the variation of urban fractional vegetation cover(FVC)in 328 cities in China from 1990 to2022 was quantified based on Landsat satellite data at a 30-m resolution.It was found that from 1990 to 2005,due to increases in building density and impervious surfaces in cities,the national mean urban vegetation cover decreased from 0.38 to 0.35.After2005,urban vegetation cover began to reverse,reaching 0.45 in 2022.This increasing trend was most pronounced in newly built urban districts.The decrease in average urban vegetation cover before 2005 was mainly due to the expansion of low vegetation cover areas,while the increase in urban vegetation cover after 2005 manifested as the expansion of high vegetation cover areas.The reversal in the trend of urban vegetation cover change after 2004 is related to the gradual implementation of national policies requiring increased urban green space coverage.The urban gross domestic product(GDP)showed the highest correlation with changes in urban vegetation cover.For large and medium-sized cities,the top three factors influencing vegetation cover were GDP,urban population,and temperature.However,for cities in arid/semi-arid regions,changes in vegetation cover were more sensitive to climatic factors(such as precipitation).Although the urban vegetation cover in China has substantially increased in recent years,the urban green space in small-sized cities and in the old urban districts of large-sized cities still have room to improve.

关键词： Urban vegetation Urban vegetation cover Urbanization Remote sensing

Inverse design of mechanical metamaterial achieving a prescribedconstitutive curve

在线全文

学校读者我要写书评

暂无评论

Theoretical & Applied Mechanics Letters 2024年第1期14卷 16-22页

作者： Zongliang Du Tanghuai Bian Xiaoqiang Ren Yibo jia Shan Tang Tianchen Cui xu Guo State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDepartment of Engineering MechanicsDalian University of TechnologyDalian 116023China Ningbo Institute of Dalian University of Technology Ningbo 315016China

Besides exhibiting excellent capabilities such as energy absorption,phase-transforming metamaterials offer a vast design space for achieving nonlinear constitutive relations.This is facilitated by switching between different patterns under deformation.However,the related inverse design problem is quite challenging,due to the lack of appropriate mathematical formulation and the convergence issue in the post-buckling analysis of intermediate designs.In this work,periodic unit cells are explicitly described by the moving morphable voids method and effectively analyzed by eliminating the degrees of freedom in void regions.Furthermore,by exploring the Pareto frontiers between error and cost,an inverse design formulation is proposed for unit cells.This formulation aims to achieve a prescribed constitutive curve and is validated through numerical examples and experimental results.The design approach presented here can be extended to the inverse design of other types of mechanical metamaterials with prescribed nonlinear effective properties.

关键词： MetamaterialPattern-transformationConstitutive curveInverse design