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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
文摘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.
基金supported by the National Key Research and Development Program of China (2021YFF1000500)National Natural Science Foundation of China (32025004, 32161133014, and31921001)Beijing Outstanding University Discipline Program。
文摘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.
基金financially supported by the National Key Research and Development Program of China(Grant No.2018YFD1000101,2019YFD1000803)Shaanxi Apple Industry Science and Technology Project(Grant No.2020zdzx03-01-04)+1 种基金Tang Scholar by Cyrus Tang Foundation(Grant No.C200022002)The China Apple Research System(Grant No.CARS-27).
文摘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^(+).
基金supported by grants from the National Basic Research Program of China(973 Program)(2012CB967900. 2012CB967901)the National Nature Science Foundation of China(NSFC81400472)
文摘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.
基金supported by grants from the National Natural Science Foundation of China(Grant Nos.51872104,51972257 and 51672205)the National Key R&D Program of China(Grant No.2016YFA0202602)the Natural Science Foundation of Hubei Province(2018CFB581).
文摘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.
基金supported by the National Natural Science Foundation of China,Nos.81901098(to TC),82201668(to HL)Fujian Provincial Health Technology Project,No.2021QNA072(to HL)。
文摘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.
基金This research was supported by the Innovation Fund of Nanjing Medical University(CX2003002)Natural Science Foundation of Jiangsu Province(BK2006246)+1 种基金Science Development Project of Jiangsu Science and Technology Department(BJ200051)and College Science Research Project of Jiangsu Education Department(OOKJBS20009).
文摘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.
基金the National Natural Science Foundation of China(31960324)。
文摘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.
文摘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.
基金supported by the National Basic Research Program of China(973 Program,2007CB109306)the National Natural Science Foundation of China(30571018)+1 种基金the Natural Science Foundation of Beijing,China(6062025)the International Plant Nutrition Institute
文摘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.
基金support and purchase of Hewlett-Packard 6890 GC-Hewlett-Packard 5973N MSD instrument.
文摘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.
基金Funded by the Natural Science Foundation Key Project of Hubei Province(No.2011CDA060)
文摘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 ℃.
基金granted by China Geological Survey Project(12120113087700)Fundamental Research Funds for the Central Universities(2652014017)+10 种基金the National Eleventh Five-year Supporting Plan for Science and Technology(2006BAD10B04)Specialized Research Funds for Doctoral Program of Higher Education(1999049114)supported by the Provincial Science and Technology Programs of Henan(0524250042)Inner Mongolia(20020307)Shanxi(001065)Beijing(953500400)enterprises of Shaanxi Daqin Potassium Industry CorporationTongling Chemical Industry Group CorporationShanxi Ziguang Potassium Industry CorporationHenan Qianhe Mining Corporationthe Geological Survey of Tianjin
文摘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.
基金Supported by the National Key Research and Development Program of China under Grant Nos 2016YFA0300600 and2016YFA0301500the National Natural Science Foundation of China under Grant Nos 11474347,61227902 and 61775232
文摘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.
文摘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.
基金NJ Governor’s Council for Medical Research and Treatment of Autism predoctoral fellowship (CAUT23AFP015) to ABNational Science Foundation grant (2030348) to FS。
文摘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.