Calcium-Magnesium Ca/Mg Ratios and Their Agronomic Implications for the Optimization of Phosphate Fertilization in Rainfed Rice Farming on Acidic Ferralsol in the Forest Zone of Ivory Coast

This study is a contribution to improving rice productivity on acidic plateau soils of the tropical rainforest zone. It is based on taking into account the cationic balances of the soil in order to optimize the phosphorus (P) nutrition of rice on these acidic soils, where this nutrient constitutes a limiting factor for agricultural production. Three (3) pot trials were conducted in Adiopodoumé in the forested south of Côte d’Ivoire. The interactive effects of calcium carbonate (0, 25, 50 and 75 kg Ca ha−1) and magnesium sulfate (0, 25, 50 and 75 kg Mg ha−1) were evaluated on the response of NERICA 5 rice at doses 0, 25, 50 and 75 kg P ha−1 of natural phosphate from Togo, applied only once at the start of the experiment. Additional fertilizers of nitrogen (N) (100 kg N ha−1) and potassium (K) (50 kg KCl ha−1) were added to each of the tests in a split-plot device. The test results revealed a paddy production potential of approximately 3 to 5 t⋅ha−1 for NERICA 5 on an acidic soil, under the effect of the interaction of P, Ca and Mg. The quadratic response of rice yield to the doses of these fertilizers would be more dependent on their balance, itself influenced by Ca nutrition. For the sustainability and maintenance of rice production in agro-ecology studied, it was recommended doses of 38 kg Ca ha−1, 34 kg Mg ha−1 in a Ca/Mg ratio (1/1) with intakes of 41 kg P ha−1, overall in a ratio 1/1/1 (P/Ca/Mg) more favorable to the availability of free iron considered a guiding element of mineral nutrition. Thus, these promising results should be confirmed in a real environment for better management of the fertilization of rice cultivated on acidic plateau soils in Côte d’Ivoire.

Mg/Ca,Ba/Ca,and S/Ca ratios as environmental and growth proxies for bivalve shells from the Haima cold seep,South China Sea

Bivalve shell fossils,cemented by authigenic carbonates,are widely spread in the Haima cold seep,Qiongdongnan Basin of the South China Sea(SCS).In this study,we examined an element profile of Gigantidas platifrons in the Haima cold seeps at a water depth of 1381 m.Based on the scanning electron microscope(SEM)analyses,the prismatic layer and nacreous layer were identified,which are characterized by prismatic structure and stratified structure,respectively.In addition,the profile can be subdivided into two parts:altered and unaltered zones.Laser inductively coupled plasma mass spectrometry(LA-ICP-MS)mapping shows that the element concentrations of the altered zones were influenced by the authigenic carbonate rocks,whereas the element concentrations of unaltered zones remain stable.In-situ X-ray diffraction(XRD)analyses show that the mineral constituent of the prismatic layer is mainly composed of aragonite.Along with the growth profile,Mg/Ca ratios of unaltered zones have minor variations,ranging 0.72-0.97 mmol/mol(mean=0.87 mmol/mol),with estimated temperatures of 3.8-4.1℃,indicating that the temperature of the surrounding seawater remains constant and agree with the measured data of 3.9℃which was conducted by a conductivity-temperature-depth system(CTD).The minor variations of Ba/Ca ratios(0.01-0.06 mmol/mol;mean=0.04 mmol/mol)indicate a relatively stabilized salinity of the surrounding seawater.S/Ca ratios show large variations of 0.04-4.15 mmol/mol(mean=1.37 mmol/mol).S/Ca ratios have regular variations which generally correspond to the variations of the Mg/Ca ratios,highlighting that the S/Ca ratios of bivalve shells show the potential to reflect the growth rate of the Gigantides.However,further studies should be carried out on the understanding of the links between the S/Ca ratios and seepage intensity of cold-seep fluids.

温阳益气活血方对慢性心力衰竭大鼠心肌组织Na^(+)-K^(+)-ATP酶、Ca^(2+)-ATP酶的影响

目的观察温阳益气活血方对慢性心力衰竭大鼠心肌组织Na^(+)-K^(+)-ATP酶、Ca^(2+)-ATP酶的影响,探讨其治疗心力衰竭的作用机制。方法采用皮下多点注射异丙肾上腺素制备慢性心力衰竭大鼠模型,将成模大鼠随机分为模型组、西药组和温阳益气活血方低、中、高剂量组,每组14只,另设空白组15只,给药组分别予相应药物灌胃,空白组和模型组予等量生理盐水,连续6周。超声检测大鼠心功能,ELISA检测血清脑钠肽(BNP)含量,计算心脏质量指数(HMI),HE染色观察心肌组织病理变化,酶活比色法、免疫组化及RT-PCR检测心肌组织Na^(+)-K^(+)-ATP酶、Ca^(2+)-ATP酶活性及表达。结果与空白组比较,模型组大鼠左室射血分数(LVEF)、左室短轴缩短率(LVFS)显著降低(P<0.01);血清BNP含量显著增加,HMI显著升高(P<0.01);心肌组织大量纤维水肿,胞质疏松,组织边缘心肌纤维溶解,伴有少量淋巴细胞浸润;心肌组织Na^(+)-K^(+)-ATP酶、Ca^(2+)-ATP酶活性显著减弱,蛋白及mRNA表达显著降低(P<0.01)。与模型组比较,温阳益气活血方高剂量组大鼠LVEF、LVFS显著升高(P<0.01);血清BNP含量显著减少,HMI显著降低(P<0.05,P<0.01);心肌纤维水肿、胞质疏松、炎症浸润、细胞空泡变性及纤维溶解程度均有改善;心肌组织Na^(+)-K^(+)-ATP酶和Ca^(2+)-ATP酶活性显著增强,蛋白及mRNA表达显著升高(P<0.01)。结论温阳益气活血方能通过调节心肌Na^(+)-K^(+)-ATP酶、Ca^(2+)-ATP酶活性及表达改善心力衰竭大鼠心功能不全,发挥治疗慢性心力衰竭的作用。

Influence of Ca/P ratio on the catalytic performance of hydroxyapatite for decarboxylation of itaconic acid to methacrylic acid

Methacrylic acid,an important organic chemical,is commercially manufactured starting from fossil feedstock.The decarboxylation of itaconic acid derived for biomass is a green route to the synthesis of methacrylic acid.In view of the problems existing in the researches on this route such as use of noble metal catalyst,harsh reaction conditions and low desired-product yield,we prepared a series of hydroxyapatite catalysts with different Ca/P molar ratios and evaluated their catalytic performance.The results showed that the hydroxyapatite catalyst with a Ca/P molar ratio of 1.58 had the best catalytic activity.The highest yield of MAA up to 61.2%was achieved with basically complete conversion of itaconic acid under the suitable reaction conditions of 1 equivalent of NaOH,2 MPa of N_(2),250℃,and 2 h.On this basis,a reaction network for the decarboxylation of itaconic acid to methacrylic acid catalyzed by hydroxyapatite was established.With the aid of catalyst characterization using X-ray powder diffraction,NH3/CO2 temperature-programmed desorption,N_(2)physisorption,inductively coupled plasma optical emission spectrometry,and scanning electron microscopy,we found that the distribution of surface acid sites and basic sites,crystal growth orientation,texture properties and morphology of hydroxyapatite varied with the Ca/P molar ratio.Furthermore,the change of the crystal growth orientation and its influence on the surface acidity and alkalinity were clarified.

Identification of Rice Accessions Associated with K+/Na+ Ratio and Salt Tolerance Based on Physiological and Molecular Responses

The key for rice plant survival under Na Cl salt stress is maintaining a high K^+/Na^+ ratio in its cells. Selection for salt tolerance rice genotypes based on phenotypic performance alone will delay in progress in breeding. Use of molecular markers in tandem with physiological studies will help in better identification of salt tolerant rice accessions. Eight rice accessions along with the check Dongjin were screened using 1/2 Yoshida solution with 50 mmol/L NaCl at the seedling stage. The accessions IT001158, IT246674, IT260533 and IT291341 were classified as salt tolerant based on their K^+/Na^+ ratios. Seventeen SSR markers reported to be associated with K^+/Na^+ ratio were used to screen the accessions. Five SSR markers(RM8053, RM345, RM318, RM253 and RM7075) could differentiate accessions classified based on their K^+/Na^+ ratios. Banding pattern of the accessions was scored compared to the banding pattern of Dongjin. The study differentiated accessions based on their association of K^+/Na^+ ratio with molecular markers which are very reliable. These markers can play a significant role in screening large set of rice germplasms for salt tolerance and also help in identification of high-yielding varieties with better salt tolerance. The salt tolerant accessions can be taken forward into developing better varieties by conventional breeding and exploring genes for salt tolerance.

Rise and decline of ancient salt industry revealed by Na and Ca concentrations in sediments at Zhongba site, Chongqing

Based on dynastic period division and AMS ^14 C dating performed on the sedimentary layers at Zhongba and Yuxi sites,and also the analysis of Na,Ca and Mg of 201 sedimentary samples from Zhongba site and that of Ca and Na in 47 sedimentary samples from Yuxi by using an inductively coupled plasma-mass spectrometry（ICP）,we found that there were 35 time periods when the contents of Ca and Na were reversely correlated,i.e.whenever the content of Ca was the highest,the content of Na was the lowest,and vice versa. Among them,there were 21 time periods when the content of Ca was the highest,and Na was the lowest,indicating that there were about 21 prosperous periods of ancient salt production at Zhongba site since 3000BC.Other 14 time periods with the peak values of Na while the low values of Ca indicate 14 declined periods of salt production at Zhongba site since 3000BC.The conclusion obtained from the reverse relationship between Ca and Na contents in this paper is consistent with that＂the salt production at Zhongba site started in the new stone age,developed in the Xia and Shang dynasties,reached at the heyday in periods from the Western Zhou to the Han Dynasties,maintained stable to develop in the Tang and the Song dynasties,and gradually declined after the Song Dynasty because the sea salt were conveyed into Sichuan region,however,still had production in the 1970s-1980s＂,educed from archeological exploration.All the above mentioned results indicate that there is a reverse relationship obviously between the contents of Na and Ca in sediments at Zhongba site for ancient salt production,which can be used to reveal the process of rise and decline of ancient salt industry at Zhongba site.

Phase Structure, Microstructure and Electrical Properties of K_xNa_((1-x))NbO_3 Piezoelectric Ceramics with Different K/Na Ratio

The K_xNa_((1-x))NbO_3(x=0.45, 0.46, 0.47, 0.48, 0.49, 0.50) lead-free piezoelectric ceramics was fabricated by conventional solid-state sintering method. It was found that the ratio of alkaline metal would affect the microstructure, bulk density, and optimum sintering temperatures of ceramics. Meanwhile, the electrical properties were also influenced by modulating the K/Na ratio, exhibiting corresponding composition-dependent properties. The optimum electrical properties of K_xNa_((1-x))NbO_3 such as piezoelectric constant d_(33) = 115 pC/N, mechanical quality factor Q_m = 20, Curie temperature Tc = 365 ~oC, ε_(33)~T/ε_0= 588.1, dielectric loss tan δ = 0.024, bulk density(ρ) = 3.08 g/cm^3, remnant polarization(P_r) = 8.87 μC/cm^2 and coercive field(Ec) = 13.79 kV/cm were obtained at x = 0.46.

Seasonal dynamics of N:P ratio stoichiometry and Ca fraction for four dominant plants in the Alxa Desert

Desert plants take on unique physiologically adaptive mechanisms in response to an adverse environment. In this study, we determined the concentrations of leaf nitrogen(N), phosphorus(P), and calcium(Ca) fraction for dominant species of Artemisia ordosica, A. frigida, Calligonum mongolicum, and Oxytropis aciphylla in the Alxa Desert and discussed seasonal changes of their leaf N:P ratio and Ca fraction. The results showed that, from May to September, the N:P ratios of A. ordosica and C. mongolicum gradually and significantly increased, while those of A. frigida, and O. aciphylla had an increase trend that was not significant; the physiologically active Ca of A. ordosica and A. frigida increased significantly,while that of C. mongolicum and O. aciphylla decreased significantly. The physiologically inert calcium of C. mongolicum increased extremely significantly, while that of others was not significant. There was a significantly positive correlation between the N:P ratio and physiologically active Ca for A. ordosica, and the N:P ratio was significantly and negatively correlated with physiologically active Ca for O. aciphylla. These findings revealed that the physiological regulation mechanism was different for the plants either in earlier stage or later stage of plant-community succession.

Morphotype dependence of Globigerinoides ruber(white)and Trilobatus sacculifer Mg/Ca ratios in the western tropical Pacific:implications for reconstructing the mixed-layer depth

Planktonic foraminifer Globigerinoides ruber(white)and Trilobatus sacculifer are the most frequently used mixedlayer dwelling species for reconstructing past oceanic environments.Specifically,the Mg/Ca ratios of these two foraminiferal species have been used for reconstructing tropical/subtropical changes in sea surface temperature(SST).However,these two species have different morphotypes,of which the spatial and temporal differences in Mg/Ca ratios and their influencing factors are still unclear.Our objective is to investigate the potential differences between the Mg/Ca ratios of these different morphotypes of G.ruber(white)and T.sacculifer in the western Philippine Sea(WPS)and determine their implications for the reconstruction of SST and upper-ocean structure.Mg/Ca measurements are made on two basic morphotypes of G.ruber(white)[sensu stricto(s.s.)and sensu lato(s.l.)]and T.sacculifer[with(w)and without(w/o)a sac-like final chamber]on samples of Site MD06-3047B from the WPS.Our results reveal that Mg/Ca ratios of different G.ruber morphotypes show consistent differences;and those of T.sacculifer morphotypes show staged variations since MIS 3.It is suggested to select a single morphotype for reconstructing SST changes using the Mg/Ca ratios of G.ruber and T.sacculifer in the WPS.Furthermore,the Mg/Ca ratios between G.ruber s.s.and G.ruber s.l.[Δ(Mg/Ca)_(G.ruber s.s.-s.l.)]downcore MD06-3047B covaries with indexes of summer monsoon.Combining with the core-top results,showing regional variation of differences in theΔ(Mg/Ca)_(G.ruber s.s.-s.l.)over the western tropical Pacific,we propose thatΔ(Mg/Ca)_(G.ruber s.s.-s.l.)may tend to reflect summer mixed layer depth.

Preliminary determination of calcium,phosphorus,and the calcium/phosphorus ratio in cortical bone of Chinstrap penguin using synchrotron X-ray fluorescence analysis

Synchrotron radiation X-ray fluorescence （SR-XRF） approach was applied to analyzing of Chinstrap penguin （ Pygoscelis Antarctica） cortical bone. The method enabled the in situ determination of Ca and P concentrations and the Ca/P ratio in cortical bone. The preliminary results show that ： （ 1 ） there is the bone site-related difference for Ca and P concentrations. The mean values for the investigated parameters （ on a dry-weight basis） are： 30.7% （Ca） and 14.9% （P） for the femoral cortical bone, 21.4% （Ca） and 11.5% （P） for wing cortical bone. （2） The variation for the Ca/P ratio in cortical bone is lower than those for Ca and P separately. This is in agreement with the previous report that the specificity of the Ca/P ratio is better than that of Ca and P concentrations and is more reliable for the diagnosis of bone disorders. The authors suggest that further studies be conducted to establish norreal values of Ca, P and Ca/P ratio for polar animals and provide a basis for the diagnosis of bone disorders.

Effect of various Na/K ratios in low-salinity well water on growth performance and physiological response of Pacific white shrimp Litopenaeus vannamei

To investigate the influence of sodium to potassium(Na/K) ratios on the growth performance and physiological response of the Pacific white shrimp( Litopenaeus vananmei), various concentrations of KCl were added to low-salinity well water(salinity 4) in an 8-week culture trial. Six treatments with Na/K ratios of 60:1, 42:1, 33:1, 23:1, 17:1, and 14:1 were replicated in triplicate. The highest weight-gain rate(3 506±48)% and survival rate(89.38±0.88)% was observed in well water with Na/K ratios of 23:1 and 42:1, respectively, while the feed conversion ratio(1.02±0.01), oxygen consumption, and ammonia-N excretion rate was the lowest in the medium with a Na/K ratio of 23:1. Gill Na +-K +-ATPase activity, as an indicator of osmoregulation, peaked in the treatment where the Na/K ratio was 17:1. The total hemocyte count, respiratory burst, and immune-related enzyme activities(ALP, LSZ, PO, and SOD) of L. vananmei were affected significantly by Na/K ratios( P <0.05). After challenged with Vibrio harveyi, the cumulative mortality of shrimp reared in a Na/K ratio of 23:1(30±14.14)% was significantly lower than the control(75±7.07)%. In conclusion, the addition of K + to low-salinity well water in L. vannamei cultures is feasible. Na/K ratios ranging from 23:1 to 33:1 might improve survival and growth. Immunity and disease resistance are also closely related to the Na/K ratio of the low-salinity well water. The findings may contribute to the development of more efficient K + remediation strategies for L. vananmei culture in low-salinity well water.

Coral Ba/Ca and Mn/Ca Ratios as Proxies of Precipitation and Terrestrial Input at the Eastern Offshore Area of Hainan Island

Geochemical ratios in coral reef skeletons could be used as proxies to reconstruct past climatological and environmental records in data-poor regions. Using a 103-year data set(1902 to 2005), the annual variations in Ba/Ca and Mn/Ca ratios of Porites lutea skeletons at an eastern offshore area of Hainan Island(19?12'28.4''N, 110?37'38.8''E) were analyzed using inductively coupled plasma-optic emission spectrometry(ICP-OES). The analysis results showed that Ba/Ca ratios varied from a minimum of 3.120 μmol mol^(-1) in 1903 to a maximum of 10.064 μmol mol^(-1) in 1944, with an average of 5.256 μmol mol^(-1). Mn/Ca ratios varied from 0.206 to 5.708 μmol mol^(-1) with an annual average of 1.234 μmol mol^(-1), with peak values in 2001, 1964 and 1932, that correlated with strong rainfall events caused by typhoons. Variation in Ba/Ca and Mn/Ca ratios were compared with available river discharge and precipitation records, providing insight into past climatological events. Human activities and their indirect effects could impact the strength of the relationship between Ba/Ca and Mn/Ca ratios and observed precipitation and terrestrial input in the future.

PREPARATION OF Pb-Ca-Na MASTER ALLOY USING MOLTEN CHLORIDE SALT ELECTROLYSIS

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MELD-Na评分联合NLR预测肝硬化食管胃静脉曲张破裂出血后再出血的临床价值

目的探讨终末期肝病模型与血钠(MELD-Na)评分联合中性粒细胞计数/淋巴细胞计数比值(NLR)预测肝硬化食管胃静脉曲张破裂出血(EGVB)后再出血的临床价值。方法选取2019年1月-2022年8月我院收治的肝硬化EGVB患者179例纳入研究,入院当日为观察起点,观察3个月内患者再出血情况,将其分为再出血组(n=42)和未出血组(n=137)。通过多因素Logistic回归分析模型分析影响肝硬化EGVB患者3个月内发生再出血的危险因素,并绘制受试者工作特征曲线(ROC)评估MELD-Na评分联合NLR对肝硬化EGVB患者3个月内发生再出血的预测价值。结果3个月内患者再出血率23.46%。再出血组腹水中轻和重度占比、肝性脑病占比、Child C级占比及NLR、MELD-Na评分均高于未出血组(P<0.05);再出血组门静脉流速、无腹水患者占比、Child A级和B级占比、HB水平、血钠水平均低于未出血组(P<0.05)。Logistic回归分析显示,低门静脉流速、高NLR、高MELD-Na评分及Child分级C级均是影响EGVB患者发生再出血的危险因素(P<0.05)。ROC曲线显示,NLR联合MELD-Na评分预测肝硬化EGVB患者3个月再出血的AUC(95%CI)为0.888(0.832~0.930),高于二者单独预测的AUC(95%CI)为0.761(0.692~0.822)、0.853(0.792~0.901),且联合预测的特异度、准确度高于单项指标(P<0.05)。结论MELD-Na评分和NLR水平高均是影响肝硬化EGVB患者再出血的危险因素,且二者联合应用对预后再出血的评估有重要参考价值。

共晶型Al-Si合金中(Ca_(n-x),Na_x)P_m化合物的形成与磷变质失效分析

利用金相和电子探针微量分析仪(EPMA)等手段研究了共晶型Al-si(ZL109)合金熔体中Ca或(和)Na对Al-P中间合金变质效果的影响、含磷化合物的组成与磷变质的关系,结果表明,合金中Ca或(和)Na能使磷变质失效,甚至出现反常的Na变质效果;Ca或(和)Na促使AlP分解,并与磷形成比AlP更稳定的(Ca_(n-x),Na_x)P_m化合物,从而抑制了磷变质作用的发挥;C_2Cl_6精炼可使(Ca_(n-x),Na_x)P_m化合物的组成和结构发生转化,形成了能作为初晶Si结晶核心的(Al_5,Mg_(0.85),Ca_(0.15))P_(3.4)化合物,从而使磷变质效果得以恢复。

惰性气氛下准东煤Na/Ca释放特性的研究

基于准东煤中Na/Ca的赋存形态,采用管式加热炉研究了准东煤中Na/Ca在惰性气氛下的释放特性和形态转变。结果表明,水溶态Naw在加热温度t≤600℃时先转变成不可溶态Nare,随着温度升高,不可溶态Nare又重新转变成水溶态Naw,当加热温度t>800℃时,Na大量释放。酸溶态Caac在加热温度t≤700℃时先分解生成CaO并且与其他矿物组分反应转变成不可溶态Care,随着温度升高,不可溶态Care逐渐转变成酸溶态Caac和水溶态Caw。相同温度条件下,Ca的释放率低于Na的释放率,少量酸溶态有机Ca随挥发分释放而以气相形式释放。

石膏及白虎汤的清热作用与对血清Na/Ca比值影响的实验研究

目的:研究石膏及白虎汤对发热模型大鼠的清热作用以及对大鼠血清Na/Ca比值的影响。方法:大鼠背皮下注射干酵母混悬液复制致热模型,观察石膏及白虎汤的清热作用;取造模前、后和给药后3个时间点的大鼠血清,微波消解,ICP-OES测定血清中Na、Ca含量,分析Na/Ca比值的变化。结果:石膏及白虎汤对干酵母致热模型大鼠均有清热作用,白虎汤效果显著;白虎汤组发热模型大鼠血清中Na/Ca比值明显降低。结论:石膏及白虎汤清热作用机理可能与降低体内Na/Ca比值有关。

槟榔不同叶序K、Ca、Na、Mg含量的测定与变化规律

对槟榔不同叶序叶片的K、Ca、Na、Mg含量进行了测定并对其变化规律进行了分析。结果表明：1—7叶序K元素含量明显减少，Ca元素含量明显增加，Na元素含量各叶序间无明显变化趋势，Mg元素含量1—5叶较稳定，第7叶有下降趋势。成龄树叶片K含量变化范围为4237．9～8999．8μg/g，Ca为2880．3～5988．5μg/g，Na为91．7～154．0μg／g，Mg为1307．6～1866．1μg／g。第5叶宜作为营养诊断的采样叶位。

水环境(Mg^(2+)+Ca^(2+))/(Na^++K^+)比值对凡纳滨对虾幼虾生长和能量收支的影响

为探索内陆天然咸水的离子组成调控方法,采用人工海水,在盐度30.2、pH8.2的条件下,研究了水环境(Mg2++Ca2+)/(Na++K+)比值对凡纳滨对虾(Litopenaeus vannamei)幼虾生长和能量收支的影响。实验持续45d,结果显示,水环境(Mg2++Ca2+)/(Na++K+)比值对凡纳滨对虾的生长、蜕皮、摄食、食物转化效率以及能量收支影响显著(P<0.05)。凡纳滨对虾对低(Mg2++Ca2+)/(Na++K+)比值的水环境耐受力很弱,而对较高(Mg2++Ca2+)/(Na++K+)比值水环境的耐受力略强。本研究表明,在以对虾养殖为目的而进行内陆天然咸水的离子组成的调节时,必须兼顾多种离子的浓度和比值,这样才能提高养殖的成功率。