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Preparation and piezoelectric properties of potassium sodium niobate glass ceramics
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作者 姜珊 王炫明 +3 位作者 李佳宇 张勇 郑涛 吕景文 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第6期560-563,共4页
This paper describes the preparation of a piezoelectric glass ceramic material from potassium sodium niobate (Ko.sNa0.sNbO3; KNN) using a novel melting method. The effects of the subsequent heat-treatment on the opt... This paper describes the preparation of a piezoelectric glass ceramic material from potassium sodium niobate (Ko.sNa0.sNbO3; KNN) using a novel melting method. The effects of the subsequent heat-treatment on the optical, thermal, electrical, and mechanical properties of the material are carefully examined, and its crystal structure and surface morphol- ogy are characterized respectively by x-ray diffraction and scanning electron microscopy. This new material has a much higher piezoelectric coefficient (163 pC.N-1) than traditional piezoelectric ceramics (131 pC.N-1 ). On this basis therefore, a strategy for the future study and development of lead-free KNN-based piezoelectric glass ceramics is proposed. 展开更多
关键词 potassium sodium niobate dielectric constant piezoelectric constant
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Measurement of the Effects of Nutritional Education for Reducing Sodium Intakes and Increasing Potassium Intakes
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作者 Tchasso Serge Kénao Jerôme Charles Sossa +6 位作者 Moussiliou Noel Paraiso Smaila Alidou Ghislain Sopoh Toyi Tchamdja Dadja Essoya Landoh Mofou Bélo Tchaa Abalo Bakaï 《Food and Nutrition Sciences》 CAS 2023年第5期436-450,共15页
Background: The Togolese population, like those around the world, frequently consumes foods high in salt/sodium and low in potassium, thus exposing them to cardiovascular disease (CVD). Nutritional intervention can he... Background: The Togolese population, like those around the world, frequently consumes foods high in salt/sodium and low in potassium, thus exposing them to cardiovascular disease (CVD). Nutritional intervention can help reverse this consumption pattern and reduce related CVD morbidity and mortality. The objective of this study was to measure the effects of a nutrition education intervention on the consumption frequencies of foods rich in sodium and potassium. Methods: The study was a quasi-experimental before- and-after study, conducted from 08 January to 16 April 2023. It involved 200 adults aged 25 - 64 years, randomly selected from two areas: an intervention area and a non-intervention area. Data were collected in two phases at 3-month intervals in both groups. The intervention consisted of nutrition education (awareness raising and cooking demonstrations) on reducing salt/sodium intake and increasing potassium-rich food intake. The kobocollect electronic questionnaire was administered to the respondents to collect data on the frequency of consumption of foods rich in sodium and potassium. Results: The median age of the respondents was 33 years old (30;38) and 56% of the participants were women, 44% and 69% respectively in the control and intervention groups. Most participants lived in rural areas (51%), 52.4% and 49.5% in the control and intervention groups respectively. Overall, 4% (p individuals reduced their frequency of adding salt at mealtime from more than 3 times a week to less than 3 times, i.e., 5.6% in the intervention group and 1.7% in the control group. The proportion of individuals who consumed meals with green leafy vegetable sauces was reduced from more than 3 times a week to less than 3 times, i.e., 7.5% (p < 0.022), or 1% in the intervention group and 4% in the control group. Education level (0.23 [0.10 - 0.50];p - 6.35];p < 0.0006) were associated with reduced salt addition at meals. The same trend was observed for increased consumption of green leafy vegetable sauces (0.95 [0.03 - 0.99];p male (2 [1.08 - 1.84];p Conclusion: This study was able to measure the effects of a nutrition education intervention for adequate sodium and potassium intakes on changing favourable dietary behaviour through a quasi-experimental study. The results show that the continuation of the intervention will contribute to the adoption of favourable behaviours for the reduction of dietary sodium intakes and the optimisation of potassium intakes. 展开更多
关键词 Nutrition Education Consumption Frequency sodium/Salt potassium TOGO
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Knowledge, Attitudes and Practices of the Populations of Dapaong and Its Surroundings in Togo on Sodium/Salt and Potassium Intakes
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作者 Tchasso Serge Kenao Jerôme Charles Sossa +7 位作者 Moussiliou Noel Paraiso Mofou Belo Mouawiyatou Bouraima Ghislain Sopoh Smaila Alidou Dadja Essoya Landoh Assima-Essodom Kalao Victoire Agueh 《Open Journal of Epidemiology》 2023年第2期113-127,共15页
Background: Food plays an important role in human health. A healthy diet contributes to the improvement of the health of populations. A diet high in sodium/salt and low in potassium has been shown to contribute to car... Background: Food plays an important role in human health. A healthy diet contributes to the improvement of the health of populations. A diet high in sodium/salt and low in potassium has been shown to contribute to cardiovascular disease. The objective of this study was to assess the knowledge, attitudes and practices (KAP) of the inhabitants of Dapaong and its surroundings on dietary intakes of sodium/salt and potassium. Methods: This was a cross-sectional study conducted from 1 November to 15 December 2022 involving 400 adults aged 25 to 44 years. Sampling was done using the probability method and the multistage random sampling technique with proportional allocation. These two methods were applied to select villages, households, and primary targets in each locality according to whether the area of residence was urban or rural. The electronic kobocollect questionnaire was administered to people in households and the interview guide was to resource persons, administrators and community leaders to collect the data. Results: Overall, 80.25% of the respondents had low knowledge of sodium/salt intakes;88.50% had poor attitudes towards the use of foods that provide more sodium/salt and 92.75% had behaviours that were not conducive to reducing excessive salt consumption. With regard to potassium, the same trend was observed in the order of 91%, 72% and 73.75%. Conclusion: The KAP levels of the people studied were not good. The populations are prone to cardiovascular disease. A multisectoral nutritional intervention would be essential to improve the knowledge of the populations on sodium/salt and potassium intakes and therefore favourable to the fight against CVD/NCD. 展开更多
关键词 KAP sodium/Salt potassium TOGO
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Therapeutic effects of potassium sodium hydrogen citrate on melamine-induced urinary calculi in China 被引量:5
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作者 GAO Jie SHEN Ying SUN Ning JIA Li-qun PAN Yue-song SUN Qiang 《Chinese Medical Journal》 SCIE CAS CSCD 2010年第9期1112-1116,共5页
Background In 2008, a sharp increase of the number of children diagnosed with urinary calculi was observed in China, 9433 children were diagnosed as having melamine-induced urinary calculi at outpatient clinic in Beij... Background In 2008, a sharp increase of the number of children diagnosed with urinary calculi was observed in China, 9433 children were diagnosed as having melamine-induced urinary calculi at outpatient clinic in Beijing Children's Hospital. This study examined the therapeutic efficacy of potassium sodium hydrogen citrate (PSHC) used to treat melamine-induced urinary stones in Chinese children who consumed melamine-containing infant formula. Methods Seventy-two infants and children (average age (18.2±7.7) months) who were diagnosed with urinary calculi were icuidomly divided into three treatment groups using the SAS Plan program. Group 1 was given a low dose (1 g/d) of PSHC, group 2 was given high dose of PSHC (2 g/d) and group 3 was given no PSHC (control group). The dose of drug was adjusted according to the baseline urinary pH. This study analyzed the influence of the dose of PSHC, the age of patients, stone size and position, and urinary pH on the level of efficacy of PSHC (cured, effectively treated or not cured).Results After 1-6 months of therapy, 19 patients from group 1, five patients from group 2 and six patients from group 3 were cured. Five patients from group 1, five patients from group 2 and four patients from group 3 were effectively treated. There were significant differences in therapeutic efficacy between the two treatment doses after 3 and 6 months as measured by the increase in the successful expulsion rate and time of melamine-induced urinary calculi. After 6 months the mean time of expulsion of urinary calculi in groups 1 and 2 was significantly shorter than in the control group. Conclusions PSHC can significantly increase the successful expulsion rate and time of melamine-induced urinary calculi. The therapeutic efficacy is affected by PSHC dose, treatment duration, calculi position, and urinary pH. There is no relationship between the therapeutic efficacy and the stone size or patient age. 展开更多
关键词 MELAMINE potassium sodium hydrogen citrate urinary calculi
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Potassium sodium niobate based lead-free ceramic for high-frequency ultrasound transducer applications 被引量:4
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作者 Jie Xing Laiming Jiang +6 位作者 Chunlin Zhao Zhi Tan Qian Xu Jiagang Wu Qiang Chen Dingquan Xiao Jianguo Zhu 《Journal of Materiomics》 SCIE EI 2020年第3期513-522,共10页
The BiAlO_(3)(BA)and(Bi_(0.5)Na_(0.5))ZrO_(3)(BNZ)are selected to form a solid solution with(K_(0.48)Na_(0.52))NbO_(3) via traditional solid state technique to optimize the electrical performance and temperature stabi... The BiAlO_(3)(BA)and(Bi_(0.5)Na_(0.5))ZrO_(3)(BNZ)are selected to form a solid solution with(K_(0.48)Na_(0.52))NbO_(3) via traditional solid state technique to optimize the electrical performance and temperature stability of KNNbased lead-free ceramics,simultaneously.Here we show that doped BA has a great influence on phase structure,morphologies,and electrical properties.The XRD patterns and dielectric constant versus temperature curves reveal that an increase in the BA content results in a transform of phase structures from a coexistence state of rhombohedral,orthorhombic and tetragonal phases to pseudocubic phase.Owing to the construction of R-O-T phase boundary,optimized performances(T_(C)~336℃,d_(33)~306 pC/N,kp=0.48)are obtained in 0.962(K_(0.48)Na_(0.52))NbO_(3)-0.003BiAlO_(3)-0.035(Bi_(0.5)Na_(0.5))ZrO_(3)(KNN-3)ceramics.Based on the sintered KNN-3 ceramic samples,high-frequency ultrasound imaging transducers are designed and fabricated,which exhibits a high center frequency of 24.5 MHz,a broad -6 dB bandwidth of 97% and a high-sensitivity.Finally,the imaging characteristic of the lead-free transducers is demonstrated via ex vivo imaging of biological tissue structure.As environment friendly materials,the excellent electrical and acoustic performance of developed KNN-based ceramics has great potential for practical applications. 展开更多
关键词 potassium sodium niobate Lead free piezoceramics Thermal stability Ultrasound imaging transducers
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Sodiophilicity/potassiophilicity chemistry in sodium/potassium metal anodes 被引量:3
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作者 Xiang Chen Yun-Ke Bai +2 位作者 Xin Shen Hong-Jie Peng Qiang Zhang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2020年第12期1-6,共6页
Heteroatom-doped carbon materials have been widely used as sodium(Na) and potassium(K) metal anode frameworks to achieve uniform Na and K depositions. If the origin of the Sodiophilicity and potassiophilicity of dopin... Heteroatom-doped carbon materials have been widely used as sodium(Na) and potassium(K) metal anode frameworks to achieve uniform Na and K depositions. If the origin of the Sodiophilicity and potassiophilicity of doping sites in heteroatom-doped carbon host are clearly understood, the nucleation and growth behavior of Na and K can be precisely regulated in working batteries. Herein the Sodiophilicity and potassiophilicity chemistries of carbon materials are probed through first-principles calculations. The local dipole of doping functional groups and charge transfer during Na/K deposition are regarded as key principles to reveal the sodiophilic and potassiophilic nature of doping sites. Especially, O–B, O–S, and O–P co-doping strategy are predicted to be effective methods to improve the Sodiophilicity and potassiophilicity of carbon hosts and thus render safe and dendrite-free Na and K metal anodes. This work affords a deep and insightful understanding of Sodiophilicity and potassiophilicity chemistry of Na and K anodes and establishes general principles of designing highly sodiophilic and potassiophilic carbon frameworks. 展开更多
关键词 sodium and potassium metal anodes Sodiophilicity and potassiophilicity Carbon materials First-principles calculations Dendrite-free electrode
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Dealloying-induced dual-scale nanoporous indium-antimony anode for sodium/potassium ion batteries 被引量:1
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作者 Hui Gao Yan Wang +4 位作者 Zhiyuan Guo Bin Yu Guanhua Cheng Wanfeng Yang Zhonghua Zhang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第12期154-163,I0005,共11页
InSb alloy is a promising candidate for sodium/potassium ion batteries(SIBs/PIBs)but challenged with achieving high performance by dramatic volumetric changes.Herein,nanoporous(np)-InSb with dualscale phases(cubic/hex... InSb alloy is a promising candidate for sodium/potassium ion batteries(SIBs/PIBs)but challenged with achieving high performance by dramatic volumetric changes.Herein,nanoporous(np)-InSb with dualscale phases(cubic/hexagonal(C/H)-InSb)was fabricated by chemical dealloying of ternary Mg-In-Sb precursor.Operando X-ray diffraction(XRD)and ex-situ characterizations well rationalize the dealloying/alloying mechanisms and the formation of dual-scale microstructures/phases.As an anode for SIB/PIBs,the np-InSb electrode exhibits superior reversible capacities and lifespan compared with the monometallic porous(p)-In electrode,stemming from the dealloying-induced dual-scale nanoporous architecture and alloying strategy with proper composition.The operando XRD results demonstrate that the(de)sodiated mechanism of the np-InSb electrode involves a two-step(de)alloying process,while the(de)potassiated mechanism is associated with a full electrochemically-driven amorphization upon cycling.Additionally,the gas evolution during the(dis)charge process was monitored by on-line mass spectrometry. 展开更多
关键词 sodium/potassium ion battery Indium-antimony anode DEALLOYING Operando X-ray diffraction On-line mass spectrometry
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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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Effects of Phorbol-12,13-dibuterate on Sodium Currents and Potassium Currents in Rat Trigeminal Ganglion Neurons 被引量:1
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作者 刘慧 胡本容 +2 位作者 付晖 向继洲 刘烈炬 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2007年第1期1-4,共4页
The effects of phorbol-12,13-dibuterate (PDBu) on total sodium current (INa-total), tetrodotoxin-resistant sodium current (INa-TFXr), 4-AP-sensitive potassium current (IA) and TEA-sensitive potassium current ... The effects of phorbol-12,13-dibuterate (PDBu) on total sodium current (INa-total), tetrodotoxin-resistant sodium current (INa-TFXr), 4-AP-sensitive potassium current (IA) and TEA-sensitive potassium current (IK) in trigeminal ganglion (TG) neurons were investigated. Whole-cell patch clamp techniques were used to record ion currents in cultured TG neurons of rats. Results revealed that 0.5μmol/L PDBu reduced the amplitude of INa-total by (38.3±4.5)% (n=6, P〈0.05), but neither the G-V curve (control: V0.5 =-17.1±4.3 mV, k=7.4±1.3; PDBu: V0.5=-15.9±5.9 mV, k=5.9±1.4; n=6, P〉0.05) nor the inactivation rate constant (control: 3.6±0.9 ms; PDBu: 3.6±0.8 ms; n=6, P〉0.05) was altered. 0.5 μmol/L PDBu could significantly increase the amplitude of INa-TFXr by (37.2± 3.2)% (n=9, P〈0.05) without affecting the G-V curve (control: V0.5=-14.7±6.0 mV, k=6.9± 1.4; PDBu: V0.5=- 11.1±5.3 mV, k=8.1± 1.5; n=5, P〉0.05 ) or the inactivation rate constant (control: 4.6±0.6 ms; PDBu: 4.2±0.5 ms; n=5, P〉0.05). 0.5 μmol/L PDBu inhibited IK by (15.6±5.0) % (n=16, P〈0.05), and V0.5 was significantly altered from - 4.7±1.4 mV to -7.9 ±1.8 mV (n=16, P〈0.05). IA was not significantly affected by PDBu, 0.5μmol/L PDBu decreased IA by only (0.3±3.2)% (n=5, P〉0.05). It was concluded that PDBu inhibited INa-total :.but enhanced INa-TFXr, and inhibited IK without affecting IA. These data suggested that the activation of PKC pathway could exert the actions. 展开更多
关键词 Phorbol-12 13-dibuterate trigeminal ganglion neurons sodium channel potassium channel
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CRYSTAL GROWTH AND PHOTOREFRACTIVE PROPERTIES OF Cu-DOPED POTASSIUM SODIUM STRONTIUM BARIUM NIOBATE
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作者 姜全忠 陈焕矗 +5 位作者 宋永远 孙大亮 许克彬 徐海英 余有龙 袁洋 《Chinese Science Bulletin》 SCIE EI CAS 1991年第8期637-640,共4页
With the progress of research on the applications of photorefractive (PR)effect in recent years, people paid more and more attention to the PR materials, especially to the modification of their properties, in order to... With the progress of research on the applications of photorefractive (PR)effect in recent years, people paid more and more attention to the PR materials, especially to the modification of their properties, in order to get crystals or ceramics with high optical quality 展开更多
关键词 potassium sodium strontimn BARIUM NIOBATE PHOTOREFRACTIVE effect crystal growth.
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Growth and morphology of potassium sodium strontium barium niobate single crystal with large diameter
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作者 宋永远 孙友轩 +1 位作者 陈焕矗 葛战勤 《Chinese Science Bulletin》 SCIE EI CAS 1995年第18期1522-1526,共5页
Potassim sodiam strontium barium niobate (K<sub>1-x</sub>Na<sub>x</sub>)<sub>2</sub>m(Sr<sub>1-y</sub>Ba<sub>y</sub>)<sub>1-m</sub>Nb<sub>2... Potassim sodiam strontium barium niobate (K<sub>1-x</sub>Na<sub>x</sub>)<sub>2</sub>m(Sr<sub>1-y</sub>Ba<sub>y</sub>)<sub>1-m</sub>Nb<sub>2</sub>O<sub>6</sub>,abbreviatedas KNSBN crystal family is one of the best photorefractive materials which can currentlycarry out the cat self-pumped phase conjugation. In recent years in the photorefractivefield. this crystal is very attractive for researcher at home and abroad because it has 展开更多
关键词 large diameter potassium sodium STRONTIUM barium NIOBATE GROWTH morphology.
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First-principles study of the local structure and crystal field of Yb^(2+) in sodium and potassium halides
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作者 闻军 段昌奎 +3 位作者 尹民 Yu.V.Orlovskii 夏上达 章永凡 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第3期349-354,共6页
The local coordination structures around the doping Yb2+ ions in sodium and potassium halides were calculated by using the first-principles supercell model. Both the cases with and without the charge compensation vac... The local coordination structures around the doping Yb2+ ions in sodium and potassium halides were calculated by using the first-principles supercell model. Both the cases with and without the charge compensation vacancy in the local environment of the doping Yb2+ were calculated to study the effect of the doping on the local coordination structures of Yb2+. Using the calculated local structures, we obtained the crystal-field parameters for the Yb2+ ions doped in sodium and potassium halides by a method based on the combination of the quantum-chemical calculations and the effective Hamiltonian method. The calculated crystal-field parameters were analyzed and compared with the fitted results. 展开更多
关键词 sodium and potassium halides local coordination structure DISTORTION crystal-field parameters
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Analgesic effect of intrathecal bumetanide is accompanied by changes in spinal sodium-potassium-chloride co-transporter 1 and potassium-chloride co-transporter 2 expression in a rat model of incisional pain 被引量:2
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作者 Yanbing He Shiyuan Xu +1 位作者 Junjie Huang Qingjuan Gong 《Neural Regeneration Research》 SCIE CAS CSCD 2014年第10期1055-1062,共8页
Accumulating evidence has demonstrated that the sodium-potassium-chloride co-transporter 1 and potassium-chloride co-transporter 2 have a role in the modulation of pain transmission at the spinal level through chlorid... Accumulating evidence has demonstrated that the sodium-potassium-chloride co-transporter 1 and potassium-chloride co-transporter 2 have a role in the modulation of pain transmission at the spinal level through chloride regulation in the pain pathway and by effecting neuronal excitability and pain sensitization. The present study aimed to investigate the analgesic effect of the speciifc sodium-potassium-chloride co-transporter 1 inhibitor bumetanide, and the change in spinal sodium-potassium-chloride co-transporter 1 and potassium-chloride co-transporter 2 expression in a rat model of incisional pain. Results showed that intrathecal bumetanide could decrease cumulative pain scores, and could increase thermal and mechanical pain thresholds in a rat model of incisional pain. Sodium-potassium-chloride co-transporter 1 expression in-creased in neurons from dorsal root ganglion and the deep laminae of the ipsilateral dorsal horn following incision. By contrast, potassium-chloride co-transporter 2 expression decreased in neurons of the deep laminae from the ipsilateral dorsal horn. These ifndings suggest that spinal sodium-potassium-chloride co-transporter 1 expression was up-regulated and spinal potassi-um-chloride co-transporter 2 expression was down-regulated following incision. Intrathecal bumetanide has analgesic effects on incisional pain through inhibition of sodium-potassi-um-chloride co-transporter 1. 展开更多
关键词 nerve regeneration sodium-potassium-chloride co-transporter 1 potassium-chloride co-transporter 2 BUMETANIDE spinal cord dorsal root ganglion incision model postoperative pain neural regeneration
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Sodium and potassium in the bones of penguin and skua revealed by EPR and SR-XRF technique
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作者 谢周清 徐思琦 +3 位作者 黄宇营 何伟 金嗣昭 孙立广 《Chinese Journal of Polar Science》 2010年第1期22-30,共9页
Penguin and skua in the maritime Antarctic have high salt loadings in the body due to almost exclusive diet consumption of marine invertebrates.However,the storage and turnover of sodium and potassium in these animals... Penguin and skua in the maritime Antarctic have high salt loadings in the body due to almost exclusive diet consumption of marine invertebrates.However,the storage and turnover of sodium and potassium in these animals are poorly investigated.Here we determined the concentration and microscopic distribution of the two elements in the bones of penguin and skua.The average concentrations of sodium and potassium in penguin bone were comparable with that in skua bone(0.18% and 0.82% for penguin bone;0.19% and 0.76% for skua bone in dry weight).The ratios of sodium to calcium and potassium to calcium(0.0330 and 0.0075 for penguin,0.0335 and 0.0082 for skua in average by weight) were somewhat higher than the reported ratios for terrestrial animals,indicating these marine animals' bone enrichment of salt.The ratios of sodium to potassium in average by weight were 6.75 and 4.65 for penguin and skua,respectively.This value is much lower compared with the bulk sea water ratio of about 27.0,implying that potassium is favorable to reside in the bone rather than sodium.Both sodium and potassium were found to significant correlation with the content of organic materials in bone based upon the intensity of native signal determined by electron paramagnetic resonance(EPR).It was estimated that almost all of potassium is kept within the organic phases,while about 30% of sodium is stored in organic phases and the other 70% within mineral phase.The microscopic distributions of potassium in the cross-section and/or surface were revealed by synchrotron radiation Xray fluorescence(SR-XRF) technique.The ratio of potassium to calcium based upon the SR-XRF intensity counter varied considerably from the surface to the interior,and on the surface the highest concentration of potassium was observed in the middle section with decreasing amounts toward the edge.This indirectly documented that exchange of potassium between fluid and bone organic phase maybe occur. 展开更多
关键词 bone penguin and skua sodium and potassium electron paramagnetic resonance(EPR) synchrotron radiation X-ray fluorescence(SR-XRF).
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Molecular dynamics simulations of valinomycin interactions with potassium and sodium ions in water solvent
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作者 Kholmirzo Kholmurodov Maria Abasheva Kenji Yasuoka 《Advances in Bioscience and Biotechnology》 2010年第3期216-223,共8页
The aim of this work is to estimate the value of the electric field (potentials) for the system of valinomycin + К+ and Na+ ions based on a molecular dynamics (MD) study. An analysis has been performed of the interac... The aim of this work is to estimate the value of the electric field (potentials) for the system of valinomycin + К+ and Na+ ions based on a molecular dynamics (MD) study. An analysis has been performed of the interaction processes for the system of valinomycin + К+(Na+) ion in water solvent. It is obtained that capturing a К+(Na+) ion in the valinomycin cavity is not possible for all values of the electric field strength. Each of the two kinds of ions (К+ or Na+) has its own critical electric field associated with ion binding to valinomycin, for which to exist, the ion has to remain localized inside the valinomycin cavity. The results obtained for the electrical potential reveal a stronger valinomycin binding—especially with the potassium ion. Valinomycin’s molecular structure efficiently surrounds the K+ ion, as this structure has to exactly correspond to the K+ ion in size. MD simulation results could be a prerequisite for studying a more complex scenario—for estimating ion transport in the cell membrane or physiological electric potential which is formed in the membrane or inside the cell relative to its surrounding medium. 展开更多
关键词 MOLECULAR Dynamics Simulations VALINOMYCIN potassium and sodium IONS
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Effects of Dingjifumai Decoction on Electrocardiogram and sodium potassium pump of rats with ventricular arrhythmia
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作者 Yan Zhou Hui-Ling Liao +1 位作者 Fei-Hu Zou Ling Luo 《TMR Modern Herbal Medicine》 2019年第1期11-18,共8页
Objective:To investigate the effect of Dingjifumai Decoction(DJFM)on Electrocardiogram(ECG)and sodium potassium pump in rats with ventricular arrhythmia.Methods:Forty healthy male SD rats(200±20g)were randomly di... Objective:To investigate the effect of Dingjifumai Decoction(DJFM)on Electrocardiogram(ECG)and sodium potassium pump in rats with ventricular arrhythmia.Methods:Forty healthy male SD rats(200±20g)were randomly divided into blank group,model group,Metoprolol group and DJFM group.Ten rats in each group were fed with normal diet and free drinking water.Each group was given gavage,and the amount of gavage in each group was calculated according to body weight.In the model group,0.001%Aconitine was injected into the tail vein at 30ug/kg.In the Metoprolol group,Metoprolol suspension was given according to the standard of 5.2mg/kg per day.In the DJFM group,DJFM was given at 17.6g/kg per day.After 2 weeks of administration,the biologic experiment system BL-420F was used to monitor the II lead ECG curve,and the ECG changes were observed and recorded.Then,the left ventricle of the rat was taken,and part of the heart tissue sodium potassium pump was detected.Results:(1)The effect of DJFM on ECG of rats with ventricular arrhythmia:After intravenous injection of aconitine,the incidence of Ventricular Premature beat(VP),Ventricular Tachycardia(VT),Ventricular Fibrillation(VF)in the model group was 100%,suggesting that the model building of rats with ventricular arrhythmia was successful.(2)VP,VT,and VF time:Compared with model group,DJFM group and Metoprolol group can significantly delay the VP,VT and VF,the difference was statistically significant(P<0.05).The effect of DJFM group and Metoprolol group on delaying the appearance of VP,VT and VF was the same,there was no significant difference(P>0.05).(3)The effect of DJFM on sodium potassium pump in rat ventricular arrhythmia heart tissues:Compared with the blank group,the sodium potassium pump value in the model group was significantly decreased,and the difference was statistically significant(P<0.05).Compared with the model group,the sodium potassium pump value of the tissues in the Metoprolol group and the DJFM group increased,and the difference was statistically significant(P<0.05).There was no significant difference in sodium potassium pump between the Metoprolol group and the DJFM group(P>0.05).Conclusion:1.The rat model of ventricular arrhythmia can be successfully prepared by intravenous injection of Aconitine.2.DJFM can prolong the occurrence time of cardiac arrhythmias caused by aconitine in rats,such as VP,VT,VF,et al.The mechanism may be related to fast Na^+channel,and it may prevent and control arrhythmias by inhibiting Na^+influx and reducing the fast response cellular self-discipline.3.DJFM can protect the myocardial tissue sodium potassium pump,which can protect the myocardial cells and improve the myocardial metabolism. 展开更多
关键词 Dingjifumai Decoction Ventricular Arrhythmia RATS ELECTROCARDIOGRAM sodium potassium pump
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Method for Tentative Evaluation of Membrane Permeability Coefficients for Sodium and Potassium Ions in Unicellular Organisms
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作者 Atanas Todorov Atanasov 《Open Journal of Biophysics》 2013年第1期91-98,共8页
The membrane permeability coefficient for sodium and potassium ions in unicellular organisms can be calculated using the data for cell volume, surface and mean generation time during growth and dividing of cells by bi... The membrane permeability coefficient for sodium and potassium ions in unicellular organisms can be calculated using the data for cell volume, surface and mean generation time during growth and dividing of cells by binary. Accordingly theory of proposed method, the membrane permeability coefficients for passed trough outer cell membrane sodium and potassium ions, is equal to the volume of unicellular organism divided to product between cell surface and mean generation time of cells. The calculated by this way diapason of values overlaps with experimentally measured diapason of values of permeability coefficient for sodium and potassium ions. The deviation between the theoretically calculated and experimentally measured values of permeability coefficient does not exceed one order of magnitude. 展开更多
关键词 PROKARYOTES EUKARYOTES PERMEABILITY Coefficient sodium potassium Ion
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慢性心力衰竭不良预后的风险模型构建
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作者 梁浩 王雪冬 +2 位作者 孙海玲 邓帅 王青松 《河北医学》 CAS 2024年第10期1705-1711,共7页
目的:分析慢性心力衰竭不良预后的相关因素并据此构建不良预后的风险模型。方法:回顾性分析本院2022年1月至2023年1月间收治的216例慢性心力衰竭(慢性心衰)患者资料,全部患者出院后随访3个月,根据美国纽约心脏病学会心衰分级标准(NYHA分... 目的:分析慢性心力衰竭不良预后的相关因素并据此构建不良预后的风险模型。方法:回顾性分析本院2022年1月至2023年1月间收治的216例慢性心力衰竭(慢性心衰)患者资料,全部患者出院后随访3个月,根据美国纽约心脏病学会心衰分级标准(NYHA分级)评估全部患者的预后情况,据此划分为良好组171例与不良组45例。对比两组患者的一般资料、入院指标,将其中具有统计学差异的因素代入Logistic分析其与慢性心衰不良预后的关系。结果:预后不良组患者年龄、入院时间、入院NYHA分级均高于良好组,体重轻于良好组,入院收缩压低于良好组,K、Na、Cl均低于良好组(P<0.05);年龄偏大、住院时间较长、入院NYHA分级较高为慢性心衰不良预后的危险因素(OR≥1,P<0.05);入院收缩压较高、体重较重、Na较高、Cl较高、K较高为慢性心衰不良预后的保护因素(OR<1,P<0.05);Na≤127.95mmoL/L及联合风险模型对于慢性心衰不良预后具有较高预测价值(AUC>0.9,P<0.05);K≤3.42mmoL/L、Cl≤94.00mmoL/L对于慢性心衰不良预后具有中等预测价值(0.7<AUC≤0.9,P<0.05);收缩压≤133.50mmHg、入院体重≤66.45kg、年龄≥61.50岁、住院时间≥15.50d、入院NYHA分级≥3.5级对于慢性心衰不良预后具有较低预测价值(0.5≤AUC≤0.7,P<0.05)。结论:根据风险模型完善患者相关检查,及时给予专项治疗与防治,预防低钠血症、低钾血症与低氯血症的发生有利于提高慢性心力衰竭患者的预后。 展开更多
关键词 慢性心力衰竭 不良预后 风险模型 血氯 血钾 血钠
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K_(0.5)Na_(0.5)NbO_(3)-x LiNbO_(3)陶瓷的相转变与压电性能温度稳定性研究
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作者 肖荣振 徐鹏 燕小斌 《压电与声光》 CAS 北大核心 2024年第5期710-715,共6页
采用常规陶瓷工艺制备了K_(0.5)Na_(0.5)NbO_(3)-x LiNbO_(3)(KNN-x LN)基无铅压电陶瓷。采用介电温度谱结合XRD系统研究了铌酸锂(LN)掺杂对KNN陶瓷相结构与压电性能温度稳定性的影响规律与机制。结果表明,LN在KNN陶瓷中的固溶度范围内... 采用常规陶瓷工艺制备了K_(0.5)Na_(0.5)NbO_(3)-x LiNbO_(3)(KNN-x LN)基无铅压电陶瓷。采用介电温度谱结合XRD系统研究了铌酸锂(LN)掺杂对KNN陶瓷相结构与压电性能温度稳定性的影响规律与机制。结果表明,LN在KNN陶瓷中的固溶度范围内(约小于10%(摩尔分数)),LN掺杂具有同时提升KNN陶瓷的T_(C)与降低陶瓷T_(O-T)的效应。当LN的掺杂量(摩尔分数)为6%时,可使陶瓷的T_(O-T)下移至室温,此时陶瓷为正交相与四方相两相共存,陶瓷的压电性能得到极大增强。T_(C)的提升增强了陶瓷的压电性能温度稳定性,当LN的掺杂量(摩尔分数)x~8%,T_(C)增加至479℃,此组分陶瓷的压电性能经470℃热处理后仍保持在室温时的71%,表现出良好的温度稳定性。当LN超过固溶度后,部分LN倾向于与K元素生成第二相,未反应的LN因其强热释电效应导致陶瓷的d 33呈现出随热处理温度升高而增强的伪增强趋势。 展开更多
关键词 铌酸钾钠 铌酸锂 相结构 居里温度 压电性能温度稳定性
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高铁酸钾-过硫酸钠降解萘的效能及机理研究
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作者 马会强 闫首龙 +1 位作者 韩佳琪 李爽 《安全与环境学报》 CAS CSCD 北大核心 2024年第3期1173-1181,共9页
为了绿色且高效地治理多环芳烃萘污染地下水,采用高铁酸钾-过硫酸钠体系降解萘,考察高铁酸钾和过硫酸钠的摩尔比、pH值和温度对萘降解效果的影响,并探究反应动力学和降解机理。研究显示,当温度为25℃,pH值为5.0,高铁酸钾和过硫酸钠的摩... 为了绿色且高效地治理多环芳烃萘污染地下水,采用高铁酸钾-过硫酸钠体系降解萘,考察高铁酸钾和过硫酸钠的摩尔比、pH值和温度对萘降解效果的影响,并探究反应动力学和降解机理。研究显示,当温度为25℃,pH值为5.0,高铁酸钾和过硫酸钠的摩尔比为1∶2时,在50 min时萘最佳降解率为82.3%。采用一级反应动力学方程对萘的降解曲线进行拟合,发现其反应速率k为0.0302 min^(-1),远高于高铁酸钾体系的0.0074 min^(-1)和过硫酸钠体系的0.0034 min^(-1)的总和,表明高铁酸钾-过硫酸钠体系存在协同作用。通过对高铁酸钾-过硫酸钠体系中Fe(Ⅱ)和Fe(Ⅲ)质量浓度变化测定,显示该体系可以活化过硫酸钠且Fe(Ⅱ)和Fe(Ⅲ)质量浓度变化与萘的降解试验结果吻合。采用自由基猝灭试验和电子顺磁共振(Electron Paramagnetic Resonance,EPR)技术探究高铁酸钾-过硫酸钠体系中的活性氧化物种,发现羟基自由基(·OH)和硫酸根自由基(·SO_(4)^(-))都参与了萘的降解过程。采用气相色谱-质谱联用仪(Gas Chromatography and Mass Spectrometry,GC-MS)分析确定了3种萘的中间产物,并提出了一种可能的降解途径。研究发现,萘在降解过程中可被转化为低毒或无毒物质,表明高铁酸钾-过硫酸钠体系对萘的降解是一个渐进降低毒性的过程,可以有效降低环境风险。总之,高铁酸钾-过硫酸钠联合体系作为一种高效的清洁技术,可为治理多环芳烃萘污染地下水提供一定的理论指导。 展开更多
关键词 环境工程学 高铁酸钾 过硫酸钠 反应动力学 降解机理
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