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Potassium Concentration by Natural ^40K-^40Ar Y Rays Detection in Four Basic Diet Products (Milk, Eggs, Wheat and Corn)
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作者 Juan Manuel Navarrete Trinidad Martinez Luis Cabrera Pilar Lizarraga Miguel Angel Zuniga Michelle Camacho 《Journal of Life Sciences》 2011年第8期614-617,共4页
The purpose of this paper is double: first to measure the natural radioactivity in any food by detecting the omnipresent radiation of ^40K, and then to use this date to obtain the concentration of the important miner... The purpose of this paper is double: first to measure the natural radioactivity in any food by detecting the omnipresent radiation of ^40K, and then to use this date to obtain the concentration of the important mineral nutrient K, by dividing the specific activity of the sample (Bq/g) by the specific activity of elementary K (31.19 Bq/g). The method implies the γ rays detection emitted by natural ^40K-^40Ar present in foodstuff, by using a 3 × 3" low background NaI (TI) scintillation detector coupled to a PC charged with the Maestro Program. When this detection system is calibrated in order to determine its efficiency for 1461 KeV γrays emitted during ^40K-^40Ar decaying, it is possible to measure easily and with enough precision the specific activity due to natural ^40K present in any foodstuff. Once this figure is divided by the constant value of ^40K specific activity of elementary K, the concentration of this element in the foodstuff sample is established. This paper describes the procedure and shows the results obtained with four basic diet products: milk (powdered, light and cream), eggs (yellow and white), wheat (whole and refined flour) and corn (whole and cornstarch flour). The possible application of this study seems to be to establish the necessary threshold to evaluate the importance of any possible radioactive contamination, as well as to measure the concentration of the mineral nutrient K in foodstuff, by means of an easy, practicable method. Also, it might be useful as an experiment for teaching purposes. 展开更多
关键词 RADIOACTIVITY NOURISHMENT potassium concentration ^40k-^40Ar Y rays.
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Potassium nutrition of maize:Uptake,transport,utilization,and role in stress tolerance 被引量:2
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作者 Meiling Zhang Yingying Hu +3 位作者 Wu Han Jian Chen Jinsheng Lai Yi Wang 《The Crop Journal》 SCIE CSCD 2023年第4期1048-1058,共11页
Potassium(K) is an essential macronutrient for plant growth and development and influences yield and quality of agricultural crops.Maize(Zea mays) is one of the most widely distributed crops worldwide.In China,althoug... Potassium(K) is an essential macronutrient for plant growth and development and influences yield and quality of agricultural crops.Maize(Zea mays) is one of the most widely distributed crops worldwide.In China,although maize consumes a large amount of K fertilizer,the K uptake/utilization efficiency(KUE)of maize cultivars is relatively low.Elucidation of KUE mechanisms and development of maize cultivars with higher KUE are needed.Maize KUE is determined by K+uptake,transport,and remobilization,which depend on a variety of K+channels and transporters.We review basic information about K+channels and transporters in maize,their functions and regulation,and the roles of K+in nitrogen transport,sugar transport,and salt tolerance.We discuss challenges and prospects for maize KUE improvement. 展开更多
关键词 MAIZE potassium Channel TRANSPORTER k uptake/utilization efficiency
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Identification of the HAK gene family reveals their critical response to potassium regulation during adventitious root formation in apple rootstock 被引量:2
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作者 Muhammad Mobeen Tahir Lu Tong +8 位作者 Lingling Xie Tong Wu Muhammad Imran Ghani Xiaoyun Zhang Shaohuan Li Xiuhua Gao Leeza Tariq Dong Zhang Yun Shao 《Horticultural Plant Journal》 SCIE CAS CSCD 2023年第1期45-59,共15页
Adventitious root formation is a bottleneck during vegetative proliferation.Potassium(K^(+))is an essential macronutrient for plants.K^(+)accumulation from the soil and its distribution to the different plant organs i... Adventitious root formation is a bottleneck during vegetative proliferation.Potassium(K^(+))is an essential macronutrient for plants.K^(+)accumulation from the soil and its distribution to the different plant organs is mediated by K^(+)transporters named K^(+)transporter(KT),K^(+)uptake(KUP),or high-affinity K^(+)(HAK).This study aimed to identify members of the HAK gene family in apples and to characterize the effects of K^(+)supply on adventitious root formation and on the expression of HAK genes and the genes that putatively control auxin transport,signaling,and cell fate during adventitious root formation.In this study,34 HAK genes(MdHAKs)were identified in the apple(Malus×domestica‘Golden Delicious’)genome.A phylogenetic analysis divided MdHAKs into four clusters(Ⅰ,Ⅱ,Ⅲ,andⅣ),comprising 16,1,4,and 13 genes,respectively.The syntenic relationships revealed that 62.5%of the total MdHAK genes arise from genomic duplication events.Chromosome location,domain structure,motif analysis,and physico-chemical characteristics were subsequently investigated.Furthermore,the application of K^(+)indicated the emergence of adventitious roots at 8 d and produced more adventitious roots at 16 d than the K^(+)-free control(CK)treatment.In addition,various MdHAKs showed root-specific expression in B9 apple rootstock stem cuttings and enhanced expression during the initiation and emergence stages of adventitious root formation in response to K^(+)treatment.Additionally,K^(+)treatment enhanced the expression levels of MdPIN1,MdPIN2,and MdAUX1.Further data indicated that a higher expression of MdWOX11,MdLBD16,and MdLBD29 and of cell cycle-related genes contributed to the auxin-stimulated adventitious root formation in response to K^(+). 展开更多
关键词 Apple rootstock Adventitious root FORMATION potassium(k+) HAk transporter
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电/高锰酸钾/过一硫酸盐体系降解活性黄K-RN及其机理
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作者 马超 孙志华 +4 位作者 王蕾 姬钰 陈翠忠 王健康 赵纯 《化工进展》 EI CAS CSCD 北大核心 2024年第10期5958-5968,共11页
印染废水中的有机染料处理在水处理技术中长久以来都是一大难题,电/高锰酸钾/过一硫酸盐体系(EC/PM/PMS体系)可以高效地降解活性黄K-RN等难降解有机污染物,但其降解机制还尚未明确,且锰类物质能否活化PMS产生活性物质以及PMS活化机理还... 印染废水中的有机染料处理在水处理技术中长久以来都是一大难题,电/高锰酸钾/过一硫酸盐体系(EC/PM/PMS体系)可以高效地降解活性黄K-RN等难降解有机污染物,但其降解机制还尚未明确,且锰类物质能否活化PMS产生活性物质以及PMS活化机理还需进一步探究。因此,本文研究了EC/PM/PMS体系在降解印染废水时活性物质的类别和产生途径,同时确定了锰类物质在其中的作用机理和PMS的活化过程。结果表明,EC/PM/PMS体系是一种包含自由基氧化和非自由基氧化的复合体系,体系中由PM还原生成五价锰、六价锰和无定形二氧化锰活化PMS。此外,明确了活性氧类自由基氧化是活性黄K-RN降解的主要路径,占比为95.3%,电极直接氧化占比2.1%,非自由基氧化占比仅为2.6%。 展开更多
关键词 电化学 高锰酸钾 过一硫酸盐 活性黄k-RN 自由基
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A new approach to endocochlear potential and potassium ion concentration measures in mini pig models 被引量:1
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作者 Lili Ren Weiwei Guo +2 位作者 Ling Zhang Wei Sun Shiming Yang 《Journal of Otology》 2014年第4期163-168,共6页
Mini pig models are large mammals and their ears are more similar with human beings in structure and development than other animals.However,the study on porcine ears is still in the initial stage and there is no descr... Mini pig models are large mammals and their ears are more similar with human beings in structure and development than other animals.However,the study on porcine ears is still in the initial stage and there is no description of an ideal operation approach to endocochlear potential and potassium ion concentration measurements.In this article,we describe a pre-auricular surgical approach to access the middle and inner ear for endocochlear potential and potassium ion concentration measures in mini pig models.Ten one-week old normal mini pigs were used in the study.The bulla of the temporal bone was accessed via a pre-auricular approach for endocochlear potential and potassium ion concentration measurements.The condition of the animals during the first post—experiment 24 h was observed.One animal died during surgery.The preauricular approach improved protection and preservation of relevant nervous and vascular elements including the facial nerve and carotid artery.So,the pre-auricular approach can be used for endocochlear potential and potassium ion concentration measurements with improved nerve and artery preservation mini pigs. 展开更多
关键词 ANATOMY Mini pig models Endocochlear potential potassium ion concentration
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Electrolyte Concentration Regulation Boosting Zinc Storage Stability of High-Capacity K0.486V2O5 Cathode for Bendable Quasi-Solid-State Zinc Ion Batteries 被引量:5
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作者 Linpo Li Shuailei Liu +7 位作者 Wencong Liu Deliang Ba Wenyi Liu Qiuyue Gui Yao Chen Zuoqi Hu Yuanyuan Li Jinping Liu 《Nano-Micro Letters》 SCIE EI CAS CSCD 2021年第2期232-245,共14页
Vanadium-based cathodes have attracted great interest in aqueous zinc ion batteries(AZIBs)due to their large capacities,good rate performance and facile synthesis in large scale.However,their practical application is ... Vanadium-based cathodes have attracted great interest in aqueous zinc ion batteries(AZIBs)due to their large capacities,good rate performance and facile synthesis in large scale.However,their practical application is greatly hampered by vanadium dissolution issue in conventional dilute electrolytes.Herein,taking a new potassium vanadate K0.486V2O5(KVO)cathode with large interlayer spacing(~0.95 nm)and high capacity as an example,we propose that the cycle life of vanadates can be greatly upgraded in AZIBs by regulating the concentration of ZnCl2 electrolyte,but with no need to approach“water-in-salt”threshold.With the optimized moderate concentration of 15 m ZnCl2 electrolyte,the KVO exhibits the best cycling stability with ~95.02% capacity retention after 1400 cycles.We further design a novel sodium carboxymethyl cellulose(CMC)-moderate concentration ZnCl2 gel electrolyte with high ionic conductivity of 10.08 mS cm^-1 for the first time and assemble a quasi-solid-state AZIB.This device is bendable with remarkable energy density(268.2 Wh kg^−1),excellent stability(97.35% after 2800 cycles),low self-discharge rate,and good environmental(temperature,pressure)suitability,and is capable of powering small electronics.The device also exhibits good electrochemical performance with high KVO mass loading(5 and 10 mg cm^-2).Our work sheds light on the feasibility of using moderately concentrated electrolyte to address the stability issue of aqueous soluble electrode materials. 展开更多
关键词 Electrolyte concentration regulation Quasi-solid-state Zn ion battery k0.486V2O5 Large interlayer spacing Cycling stability
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混合式K边界/X荧光密度计测铀钚质量浓度的不确定度分析
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作者 茆亚南 姬明 +5 位作者 范潇 王思佳 赵潇 邵婕文 柏磊 许小明 《现代应用物理》 2024年第5期17-22,共6页
为检验混合式K边界技术测量混合溶液中铀钚质量浓度的精度,使用混合式K边界/X荧光密度计(hybrid K-edge/XRF densitometer,HKED)对不同混合溶液进行了铀、钚质量浓度测量实验。根据实验数据计算了测量结果的不确定度,并分析了测量过程... 为检验混合式K边界技术测量混合溶液中铀钚质量浓度的精度,使用混合式K边界/X荧光密度计(hybrid K-edge/XRF densitometer,HKED)对不同混合溶液进行了铀、钚质量浓度测量实验。根据实验数据计算了测量结果的不确定度,并分析了测量过程中的偏差来源。通过对测量结果及不确定度的分析,验证了混合式K边界技术测量铀、钚质量浓度可达到核安全导则《核燃料后处理厂核材料衡算》中的测量精度,对标定范围内铀质量浓度的测量不确定度小于0.28%,钚质量浓度的测量不确定度基本小于0.94%,精度较高,能够满足生产中的衡算要求;总结了测量中的主要偏差来源和优化方向,为进一步提高测量精度和拓展混合式K边界技术在锕系元素测量中的应用提供数据支持。 展开更多
关键词 混合式k边界密度计 乏燃料后处理 核材料衡算 无损检测 钚质量浓度测量
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Potassium and calcium channels in different nerve cells act as therapeutic targets in neurological disorders
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作者 Qing Qiu Mengting Yang +2 位作者 Danfeng Gong Haiying Liang Tingting Chen 《Neural Regeneration Research》 SCIE CAS 2025年第5期1258-1276,共19页
The central nervous system, information integration center of the body, is mainly composed of neurons and glial cells. The neuron is one of the most basic and important structural and functional units of the central n... The central nervous system, information integration center of the body, is mainly composed of neurons and glial cells. The neuron is one of the most basic and important structural and functional units of the central nervous system, with sensory stimulation and excitation conduction functions. Astrocytes and microglia belong to the glial cell family, which is the main source of cytokines and represents the main defense system of the central nervous system. Nerve cells undergo neurotransmission or gliotransmission, which regulates neuronal activity via the ion channels, receptors, or transporters expressed on nerve cell membranes. Ion channels, composed of large transmembrane proteins, play crucial roles in maintaining nerve cell homeostasis. These channels are also important for control of the membrane potential and in the secretion of neurotransmitters. A variety of cellular functions and life activities, including functional regulation of the central nervous system, the generation and conduction of nerve excitation, the occurrence of receptor potential, heart pulsation, smooth muscle peristalsis, skeletal muscle contraction, and hormone secretion, are closely related to ion channels associated with passive transmembrane transport. Two types of ion channels in the central nervous system, potassium channels and calcium channels, are closely related to various neurological disorders, including Alzheimer's disease, Parkinson's disease, and epilepsy. Accordingly, various drugs that can affect these ion channels have been explored deeply to provide new directions for the treatment of these neurological disorders. In this review, we focus on the functions of potassium and calcium ion channels in different nerve cells and their involvement in neurological disorders such as Parkinson's disease, Alzheimer's disease, depression, epilepsy, autism, and rare disorders. We also describe several clinical drugs that target potassium or calcium channels in nerve cells and could be used to treat these disorders. We concluded that there are few clinical drugs that can improve the pathology these diseases by acting on potassium or calcium ions. Although a few novel ion-channelspecific modulators have been discovered, meaningful therapies have largely not yet been realized. The lack of target-specific drugs, their requirement to cross the blood–brain barrier, and their exact underlying mechanisms all need further attention. This review aims to explain the urgent problems that need research progress and provide comprehensive information aiming to arouse the research community's interest in the development of ion channel-targeting drugs and the identification of new therapeutic targets for that can increase the cure rate of nervous system diseases and reduce the occurrence of adverse reactions in other systems. 展开更多
关键词 ASTROCYTES calcium channels central nervous system extracellular ion concentration MICROGLIA neurological disorders NEURONS potassium channels
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Effects of Iptakalim on intracellular free calcium concentration of cultured rabbit pulmonary arterial smooth muscle cells
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作者 Xu Qi Weiping Xie +2 位作者 Gang Hu Hai Wang Hong Wang 《Journal of Nanjing Medical University》 2007年第5期282-286,共5页
Objective:To explore the effects of Iptakalim on intracellular free calcium concentration and on the proliferation of cultured rabbit pulmonary arterial smooth muscle cells induced by endothelin-1 (ET-1) in vitro. ... Objective:To explore the effects of Iptakalim on intracellular free calcium concentration and on the proliferation of cultured rabbit pulmonary arterial smooth muscle cells induced by endothelin-1 (ET-1) in vitro. Methods:A cell culture model, [^3H]-thymidine([^3H]-TdR) incorporation test and confocal microscope were used to observe proliferation and intracellular free calcium concentration([Ca^2±]) of rabbit PASMC induced by ET-1 in vitro. Results:The value of [^3H]-TdR incorporation in ET-1 group was increased 1.468 times higher than that in control group. Iptakalim at the concentration of 10^-7mol/L, 10^-6mol/L ,10^-5 mol/L lowered [^3H]-TdR incorporation by (19.8 ± 4.6)%, (41.2 ± 9.5)%, (54.7 ± 10.1)%, respectively, compared with the value of the cells treated with ET-1(P〈 0.01); The intracellular fluorescence intensity of PASMC in ET-1 group was increased from 73.70 ± 10.12 to 143.84 ± 28.23, significantly higher than that in control group(P 〈 0.01); whereas with Iptakalim,the fluorescence intensity(FI) was only increased from 74.30 ± 10.20 to 86.03 ± 9.82, significantly lower than that in ET-1 group(P 〈 0.01). Conclusion:Iptakalim inhibited proliferation of PASMC and decreased intracellular free calcium concentration of cultured rabbit PASMC induced by ET-1. 展开更多
关键词 smooth muscle cell ENDOTHELIN-1 ATP sensitive potassium channels calcium concentration
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Spectral parameter-based models for leaf potassium concentration estimation in Ping'ou hybrid hazelnut
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作者 ZHAO Shanchao PAN Cunde 《Journal of Arid Land》 SCIE CSCD 2020年第6期1083-1092,共10页
Ping′ou hybrid hazelnut is produced by cross cultivation and is widely cultivated in northern China with good development prospects.Based on a field experiment of fertilizer efficiency,the leaf spectral reflectance a... Ping′ou hybrid hazelnut is produced by cross cultivation and is widely cultivated in northern China with good development prospects.Based on a field experiment of fertilizer efficiency,the leaf spectral reflectance and leaf potassium(K)concentration were measured with different quantities of K fertilizer applied at four fruit growth stages(fruit setting stage,fruit rapid growth stage,fruit fat-change stage,and fruit near-maturity stage)of Ping′ou hybrid hazelnut in 2019.Spectral parameters that were significantly correlated with leaf K concentration were selected using Pearson correlation analysis,and spectral parameter estimation models of leaf K concentration were established by employing six different modelling methods(exponential function,power function,logarithmic function,linear function,quadratic function,and cubic function).The results indicated that at the fruit setting period,leaf K concentration was significantly correlated with Dy(spectra slope of yellow edge),Rg(reflectance of the green peak position),λo(red valley position),SDb(blue edge area),SDr/SDb(where SDr represents red edge area),and(SDr–SDb)/(SDr+SDb)(P<0.01).There were significant correlations of leaf K concentration with Dy,Rg,SDb,Rg/Ro(where Ro is the reflectance of the red valley position),and(Rg–Ro)/(Rg+Ro)at the fruit rapid growth stage(P<0.01).Further,significant correlations of leaf K concentration with Rg,Ro,RNIR/Green,and RNIR/Blue were obtained at the fruit fat-change period(P<0.01).Finally,leaf K concentration showed significant correlations with Dr,Rg,Ro,SDy(yellow edge area),and SDr at the fruit near-maturity stage(P<0.01).Through a cubic function analysis,regression estimation model of leaf K concentration with highest fitting degree(R2)values at the four fruit growth stages was established.The findings in this study demonstrated that it is feasible to estimate leaf K concentration of Ping′ou hybrid hazelnut at the various phenological stages of fruit development by establishing regression models between leaf K concentration and spectral parameters. 展开更多
关键词 leaf k concentration SPECTRUM cubic function regression models fruit growth stages Ping'ou hybrid hazelnut
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Effects of Doubled_CO_2 Concentration on Ultrastructure, Supramolecular Architecture and Spectral Characteristics of Chloroplasts from Wheat 被引量:1
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作者 左宝玉 张泉 +2 位作者 姜桂珍 白克智 匡廷云 《Acta Botanica Sinica》 CSCD 2002年第8期908-912,共5页
Wheat ( Triticum aestivum L.) plants were grown under ambient and doubled_CO 2(plus 350 μL/L) concentration in cylindrical open_top chamber to examine their effects on the ultrastructure, supramolecular architect... Wheat ( Triticum aestivum L.) plants were grown under ambient and doubled_CO 2(plus 350 μL/L) concentration in cylindrical open_top chamber to examine their effects on the ultrastructure, supramolecular architecture, absorption spectrum and low temperature (77 K) fluorescence emission spectrum of the chloroplasts from wheat leaves. The results were briefly summarized as follows: (1) The wheat leaves possessed normally developed chloroplasts with intact grana and stroma thylakoid membranes; The grana intertwined with stroma thylakoid membranes and increased slightly in stacking degree and the width of granum, in spite of more accumulated starch grains within the chloroplasts than those in control; (2) The particle density in the stacked region of the endoplasmic fracture face (EFs) and protoplasmic fracture face (PFs) and in the unstacked region the endoplasmic fracture face (EFu) and the protoplasmic fracture face (PFu) was significantly higher than that of control. Furthermore, in some cases many more particles on EFs faces of thylakoid membranes appeared as a paracrystalline particle array; (3) The variations in the structure of chloroplasts were consistent with the absorption spectra and the low temperature (77 K) fluorescence emission spectra of the chloroplasts developed under the doubled_CO 2 concentration. Results indicate that the capability of light energy absorption of chloroplasts and regulative capability of excitation energy distribution between PSⅡ and PSⅠ were raised by doubled_CO 2 concentration. This is very favorable for final productivity of wheat. 展开更多
关键词 chloroplast wheat ( Triticum aestivum ) doubled_CO 2 concentration ultrastructure and supramolecular architecture absorption spectra low temperature (77 k) fluorescence emission spectra
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Effect of Potassium on Ultrastructure of Maize Stalk Pith and Young Root and Their Relation to Stalk Rot Resistance 被引量:6
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作者 LI Wen-juan HE Ping JIN Ji-yun 《Agricultural Sciences in China》 CAS CSCD 2010年第10期1467-1474,共8页
To study the mechanism of potassium (K) application on improvement of maize resistance to stalk rot at cellular level, scanning electron microscope and transmission electron microscope were used to observe the effe... To study the mechanism of potassium (K) application on improvement of maize resistance to stalk rot at cellular level, scanning electron microscope and transmission electron microscope were used to observe the effect of K on the ultrastructure of maize stalk pith tissue and young root tip cell influenced by K and pathogen. In K deficient treatment, parenchyma cells of stalk pith had abnormal structure, and the cell wall between upper and lower adjacent cell was damaged, resulting in the loss of connections between vascular cells and insufficient supporting capacity. However, an improved K nutrition helped to keep a quite tight arrangement of root cell with thick cell wall, and prevent the invasion of pathogen effectively. Moreover, K treated root cell had abundant golgi apparatus, which could excrete large amount of secretions to degrade mycelium. Papillary and highly electronic intensity dot were accumulated at the invading point to prevent the deveJopment of the mycelium. Improved K nutrition could increase the resistant ability of maize plant to stalk rot, through keeping cell structure stability, preventing the expansion of intracellular space to reduce the chances of pathogen invasions, and through reinforcing cell wall and formation of intercellular and intracellular material to restrict further development of pathogen in host cell. 展开更多
关键词 potassium (k maize stalk rot ULTRASTRUCTURE disease resistance
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萝卜HAK/KUP/KT基因家族鉴定与表达特性分析 被引量:1
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作者 程瑞 汪国莲 +5 位作者 孙玉东 王林闯 罗德旭 王玮 仲秀娟 赵建锋 《江苏农业学报》 CSCD 北大核心 2023年第3期777-787,共11页
钾元素是植物生长发育过程中必需的主要矿质营养元素之一,对作物的产量和品质有决定性影响,细胞内K+含量水平在很大程度上受K+转运蛋白控制。通过生物信息学方法从全基因组水平鉴定出萝卜K^(+)转运蛋白HAK/KUP/KT基因家族成员,并对其基... 钾元素是植物生长发育过程中必需的主要矿质营养元素之一,对作物的产量和品质有决定性影响,细胞内K+含量水平在很大程度上受K+转运蛋白控制。通过生物信息学方法从全基因组水平鉴定出萝卜K^(+)转运蛋白HAK/KUP/KT基因家族成员,并对其基因结构、蛋白质特性、保守基序、染色体定位、启动子顺式作用元件、系统进化及表达特性等进行分析。结果表明,鉴定出的17个萝卜HAK/KUP/KT基因不均等地分布在萝卜6条染色体及Scaffold00840上,根据与拟南芥的同源关系将其命名为RsHAK1~RsHAK17;RsHAKs基因结构、保守基序、蛋白质理化特性等均具有高度保守性,启动子区域存在大量与环境因素、植物激素、逆境胁迫应答等有关的顺式作用元件;系统进化分析结果显示,17个RsHAKs基因聚为4个亚家族,全基因组复制事件是RsHAKs基因扩张的主要驱动力。转录组和qRT-PCR表达分析结果表明,除RsHAK5仅在萝卜根部表达外,其他RsHAKs在萝卜各器官及发育过程中均有特异性表达,且在高钾渗透胁迫下在叶片中相对表达量显著上调,RsHAK3、RsHAK9、RsHAK11和RsHAK12在根部呈现明显的缺钾诱导表达模式。研究结果为进一步全面解析HAK/KUP/KT基因在萝卜中的生物学功能以及提高萝卜栽培品质提供了一定理论依据。 展开更多
关键词 萝卜 钾转运蛋白 基因家族 k^(+) 表达分析
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Baeyer-Villiger oxidation of cyclic ketones utilizing potassium peroxydisulfate(K_2S_2O_8) or sodium perborate(NaBO_3) in acidic media 被引量:8
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作者 S.Zarrabi N.O.Mahmoodi +1 位作者 K.Tabatabaeian M.A.Zanjanchi 《Chinese Chemical Letters》 SCIE CAS CSCD 2009年第12期1400-1404,共5页
The efficient, green, facile, mild and straightforward conversion procedure for the oxidation of cyclic ketones to lactones at room temperature utilizing potassium peroxydisulfate (K2S2O8) in acidic media is satisfa... The efficient, green, facile, mild and straightforward conversion procedure for the oxidation of cyclic ketones to lactones at room temperature utilizing potassium peroxydisulfate (K2S2O8) in acidic media is satisfactory to high yields without using traditional chlorinated solvents is reported. This oxidative reagent is cheap and friendly environmental procedure for industrial purposes than use of organic peracids. 展开更多
关键词 Baeyer-Villiger oxidation Cyclic ketones potassium peroxydisulfate (k2S208) Acidic media Sodium perborate (NaBO3)
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Preparation of Layered Potassium Titanate Whiskers with Large Length-diameter Ratio by KDC Method 被引量:4
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作者 吉晓莉 WU Shijiang +1 位作者 章嵩 ZHAO Xiujian 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2014年第4期669-673,共5页
Pure K2Ti4O9 whiskers were prepared by KDC(Kneading-Drying-Calcination) method with TiO2 and K2CO3 as raw materials. The influences of TiO2/K2CO3 molar ratio(RT/K), calcination temperature(TC) and cooling proces... Pure K2Ti4O9 whiskers were prepared by KDC(Kneading-Drying-Calcination) method with TiO2 and K2CO3 as raw materials. The influences of TiO2/K2CO3 molar ratio(RT/K), calcination temperature(TC) and cooling process on phase composition and morphology of the whiskers were investigated by TG-DSC(thermo gravimetric-differential scanning calorimeter), XRD(X-ray diffraction), and SEM(scanning electron microscope). Pure K2Ti4O9 potassium titanate whiskers with large length-diameter ratio(r)(over 250) can be obtained at RT/K = 2.9 and TC = 950 ℃. 展开更多
关键词 kDC(kneading-drying-calcination) method potassium titanate whiskers TiO2/k2CO3 molar ratio(RT/k length-diameter ratio(r)
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20 Years Advances in Preparation of Potassium Salts from Potassic Rocks:A Review 被引量:6
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作者 MA Hongwen YANG Jing +6 位作者 SU Shuangqing LIU Meitang ZHENG Hong WANG Yingbin QI Hongbin ZHANG Pan YAO Wengui 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2015年第6期2058-2071,共14页
Long-term research on key techniques of clean utilization of potassic rocks from over twenty localities has been performed to settle the shortage of soluble potassium resources in China. The results show that K-feldsp... Long-term research on key techniques of clean utilization of potassic rocks from over twenty localities has been performed to settle the shortage of soluble potassium resources in China. The results show that K-feldspar as the principal mineral enriched in potassium could be decomposed in the media of Ca(OH)_2, NaOH, KOH-H_2O solution via hydrothermal treatment, into tobermorite, hydroxylcancrinite, and kalsilite respectively. By further processing, these compounds are feasible for being as slow-release carrier of potassium nitrate, extracting alumina, and preparing farm-oriented fertilizers of potassium sulphate and nitrate. Correspondingly, the filtrate is KOH,(Na, K)_2SiO_3, and K_2SiO_3 solution, from which potassium carbonate, sulphate, nitrate, and phosphate could be easily fabricated. As NaO H and KOH are recycled in the processing chains by causticizing sodium and/or potassium metasilicate solutions, the hydrothermal alkaline techniques as developed in this research have several advantages as lower consumption of disposable mineral resources and energy, maximized utilization of potassic mineral resources, as well as clean productions etc. Based on the approaches presented in this paper, the technical system of efficiently utilizing insoluble potassium resources has been established. The hydrothermal alkaline methods are feasible to be industrialized on a large scale, thus resulting in decreasing imports of potash fertilizers, improving the pattern of potassium fertilizer consumption, and enhancing the supplying guarantee of potassium resource in China. 展开更多
关键词 k-FELDSPAR potassium salt alkaline digestion green processing sustainable development
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Enhanced Loading of ^(40)K from Natural Abundance Potassium Source with a High Performance 2D^+ MOT 被引量:1
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作者 杨江陵 龙云 +3 位作者 高威威 晋兰 左战春 王如泉 《Chinese Physics Letters》 SCIE CAS CSCD 2018年第3期22-24,共3页
40K is one of the most important atomic species for ultra-cold atomic physics. Due to the extremely low con- centration (0.012%) of 40K in natural abundance of potassium, most experiments use 4-10% enriched potassiu... 40K is one of the most important atomic species for ultra-cold atomic physics. Due to the extremely low con- centration (0.012%) of 40K in natural abundance of potassium, most experiments use 4-10% enriched potassium source, which have greatly suffered from the extremely low annual production and significant price hikes in recent years. Using naturally abundant potassium source, we capture 5.4 × 10 6 cold 40K atoms with the help of a high performance of two-dimensional magneto-optical trap (2D+ MOT), which is almost three orders of magnitude greater than previous results without the 2D+ MOT. The number of the 40K atoms is sufficient for most ultra-cold 40K experiments, and our approach provides an ideal alternative for the field. 展开更多
关键词 Enhanced Loading of MOT k from Natural Abundance potassium Source with a High Performance 2D
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Potassium forms in calcareous soils as affected by clay minerals and soil development in Kohgiluyeh and Boyer-Ahmad Province,Southwest Iran
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作者 Sirous SHAKERI Seyed A ABTAHI 《Journal of Arid Land》 SCIE CSCD 2018年第2期217-232,共16页
Potassium(K) is known as one of the essential nutrients for the growth of plant species. The relationship between K and clay minerals can be used to understand the K cycling, and assess the plant uptake and potentia... Potassium(K) is known as one of the essential nutrients for the growth of plant species. The relationship between K and clay minerals can be used to understand the K cycling, and assess the plant uptake and potential of soil K fertility. This study was conducted to analyze the K forms(soluble, exchangeable, non-exchangeable and structural) and the relationship of K forms with clay minerals of calcareous soils in Kohgiluyeh and Boyer-Ahmad Province, Southwest Iran. The climate is hotter and drier in the west and south of the province than in the east and north of the province. A total of 54 pedons were dug in the study area and 32 representative pedons were selected. The studied pedons were mostly located on calcareous deposits. The soils in the study area can be classified into 5 orders including Entisols, Inceptisols, Mollisols, Alfisols and Vertisols. The main soil clay minerals in the west and south of the study area were illite, chlorite and palygorskite, whereas they were smectite, vermiculite and illite in the north and east of the province. Due to large amount of smectite and high content of organic carbon in soil surface, the exchangeable K in surface soils was higher than that in subsurface soils. It seems that organic matter plays a more important role than smectite mineral in retaining exchangeable K in the studied soils. Non-exchangeable K exhibited close relationships with clay content, illite, vermiculite and smectite. Although the amount of illite was the same in almost all pedons, amounts of structural and non-exchangeable K were higher in humid regions than in arid and semi-arid regions. This difference may be related to the poor reservoir of K~+ minerals like palygorskite and chlorite together with illite in arid and semi-arid regions. In humid areas, illite was accompanied by vermiculite and smectite as the K~+ reservoir. Moreover, the mean cumulative non-exchangeable K released by CaCl_2 was higher than that released by oxalic acid, which may be due to the high buffering capacity resulting from high carbonates in soils. 展开更多
关键词 clay minerals potassium forms calcareous soils oxalic acid k+ reservoir Iran
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鸟嘴式K形间隙节点应力集中系数参数化建模与分析 被引量:1
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作者 段英豪 张云梅 +1 位作者 曹勇 程斌 《建筑结构》 北大核心 2023年第2期120-126,共7页
鸟嘴式节点是一种新型的焊接方钢管节点,由于其构造上的独特性,以热点应力为目标的参数化建模分析过程较为复杂。针对常见的K形节点形式,以鸟嘴式K形间隙节点的四个无量纲参数为主要变量,建立了一套可靠高效的参数化建模方法。有限元建... 鸟嘴式节点是一种新型的焊接方钢管节点,由于其构造上的独特性,以热点应力为目标的参数化建模分析过程较为复杂。针对常见的K形节点形式,以鸟嘴式K形间隙节点的四个无量纲参数为主要变量,建立了一套可靠高效的参数化建模方法。有限元建模基于ANSYS参数化设计语言(APDL),充分考虑鸟嘴式K形间隙节点鞍部和冠部区域的几何特征,同时准确模拟角焊缝几何尺寸的影响,实现了焊趾热点应力的精细化分析和自动化提取。另外,参照国际焊接协会疲劳设计指南建议的热点应力确定方法,在焊趾外侧设立热点外推区,并对其进行网格二次划分,以满足热点应力外推计算的需求。通过与已有试验数据对比,验证了有限元模型的准确性。在此基础上开展参数化分析,发现了鸟嘴式K形间隙节点应力集中系数(SCF)随无量纲参数的变化规律。并通过数值拟合提出了相应的SCF计算公式,可用于此类新型节点的抗疲劳设计和疲劳性能评估。 展开更多
关键词 方钢管截面 鸟嘴式k形间隙节点 热点应力 应力集中系数 参数化建模
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Ion channels in neurodevelopment:lessons from the Integrin-KCNB1 channel complex 被引量:1
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作者 Alessandro Bortolami Federico Sesti 《Neural Regeneration Research》 SCIE CAS CSCD 2023年第11期2365-2369,共5页
Ion channels modulate cellular excitability by regulating ionic fluxes across biological membranes.Pathogenic mutations in ion channel genes give rise to epileptic disorders that are among the most frequent neurologic... Ion channels modulate cellular excitability by regulating ionic fluxes across biological membranes.Pathogenic mutations in ion channel genes give rise to epileptic disorders that are among the most frequent neurological diseases affecting millions of individuals worldwide.Epilepsies are trigge red by an imbalance between excitatory and inhibitory conductances.However,pathogenic mutations in the same allele can give rise to loss-of-function and/or gain-of-function va riants,all able to trigger epilepsy.Furthermore,certain alleles are associated with brain malformations even in the absence of a clear electrical phenotype.This body of evidence argues that the underlying epileptogenic mechanisms of ion channels are more diverse than originally thought.Studies focusing on ion channels in prenatal cortical development have shed light on this apparent paradox.The picture that emerges is that ion channels play crucial roles in landmark neurodevelopmental processes,including neuronal migration,neurite outgrowth,and synapse formation.Thus,pathogenic channel mutants can not only cause epileptic disorders by alte ring excitability,but further,by inducing morphological and synaptic abnormalities that are initiated during neocortex formation and may persist into the adult brain. 展开更多
关键词 developmental and epileptic encephalopathies epilepsy k+channel kCNB1 kv2.1 NEURODEVELOPMENT potassium channel
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