期刊文献+
共找到3,359篇文章
< 1 2 168 >
每页显示 20 50 100
Serum cystatin C,monocyte/high-density lipoprotein-C ratio,and uric acid for the diagnosis of coronary heart disease and heart failure
1
作者 Ming Li Da-Hao Yuan +2 位作者 Zhi Yang Teng-Xiang Luw Xiao-Biao Zou 《World Journal of Clinical Cases》 SCIE 2024年第18期3461-3467,共7页
BACKGROUND Coronary heart disease(CHD)and heart failure(HF)are the major causes of morbidity and mortality worldwide.Early and accurate diagnoses of CHD and HF are essential for optimal management and prognosis.Howeve... BACKGROUND Coronary heart disease(CHD)and heart failure(HF)are the major causes of morbidity and mortality worldwide.Early and accurate diagnoses of CHD and HF are essential for optimal management and prognosis.However,conventional diagnostic methods such as electrocardiography,echocardiography,and cardiac biomarkers have certain limitations,such as low sensitivity,specificity,availability,and cost-effectiveness.Therefore,there is a need for simple,noninvasive,and reliable biomarkers to diagnose CHD and HF.AIM To investigate serum cystatin C(Cys-C),monocyte/high-density lipoprotein cholesterol ratio(MHR),and uric acid(UA)diagnostic values for CHD and HF.METHODS We enrolled 80 patients with suspected CHD or HF who were admitted to our hospital between July 2022 and July 2023.The patients were divided into CHD(n=20),HF(n=20),CHD+HF(n=20),and control groups(n=20).The serum levels of Cys-C,MHR,and UA were measured using immunonephelometry and an enzymatic method,respectively,and the diagnostic values for CHD and HF were evaluated using receiver operating characteristic(ROC)curve analysis.RESULTS Serum levels of Cys-C,MHR,and UA were significantly higher in the CHD,HF,and CHD+HF groups than those in the control group.The serum levels of Cys-C,MHR,and UA were significantly higher in the CHD+HF group than those in the CHD or HF group.The ROC curve analysis showed that serum Cys-C,MHR,and UA had good diagnostic performance for CHD and HF,with areas under the curve ranging from 0.78 to 0.93.The optimal cutoff values of serum Cys-C,MHR,and UA for diagnosing CHD,HF,and CHD+HF were 1.2 mg/L,0.9×10^(9),and 389μmol/L;1.4 mg/L,1.0×10^(9),and 449μmol/L;and 1.6 mg/L,1.1×10^(9),and 508μmol/L,respectively.CONCLUSION Serum Cys-C,MHR,and UA are useful biomarkers for diagnosing CHD and HF,and CHD+HF.These can provide information for decision-making and risk stratification in patients with CHD and HF. 展开更多
关键词 Serum cystatin C Monocyte/high-density lipoprotein-C ratio Uric acid Coronary heart disease Heart failure Risk stratification
下载PDF
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
2
作者 Fernand G. Yao Brahima Kone +7 位作者 Franck M. L. Bahan Kouadio Amani Jean L. Essehi Mamadou B. Ouattara Konan E. B. Dibi Brou Kouame François Lompo Albert Yao-Kouame 《Open Journal of Soil Science》 2024年第1期81-96,共16页
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 phosph... 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<sup>−1</sup>) and magnesium sulfate (0, 25, 50 and 75 kg Mg ha<sup>−1</sup>) were evaluated on the response of NERICA 5 rice at doses 0, 25, 50 and 75 kg P ha<sup>−1</sup> of natural phosphate from Togo, applied only once at the start of the experiment. Additional fertilizers of nitrogen (N) (100 kg N ha<sup>−1</sup>) and potassium (K) (50 kg KCl ha<sup>−1</sup>) 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<sup>−1</sup> 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<sup>−1</sup>, 34 kg Mg ha<sup>−1</sup> in a Ca/Mg ratio (1/1) with intakes of 41 kg P ha<sup>−1</sup>, 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. 展开更多
关键词 Soil acidity Ca/Mg ratios Phosphate Fertilization Rice Growing Ivory Coast
下载PDF
Influence of Ca/P ratio on the catalytic performance of hydroxyapatite for decarboxylation of itaconic acid to methacrylic acid 被引量:1
3
作者 Shutong Pang Hualiang An +1 位作者 Xinqiang Zhao Yanji Wang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第1期402-408,共7页
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... 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. 展开更多
关键词 Biomass-derived itaconic acid Methacrylic acid Hydroxyapatite catalyst Ca/P ratio Decarboxylation reaction
下载PDF
Humic Acid Effects on Reducing Corn Leaf Burn Caused by Foliar Spray of Urea-Ammonium Nitrate at Different Humic Acid/Urea-Ammonium Nitrate Ratios
4
作者 Xinhua Yin 《Open Journal of Soil Science》 2024年第3期180-189,共10页
Technologies for reducing corn leaf burn caused by foliar spray of urea-ammonium nitrate (UAN) during the early growing season are limited. A field experiment was carried out to evaluate the effects of humic acid on c... Technologies for reducing corn leaf burn caused by foliar spray of urea-ammonium nitrate (UAN) during the early growing season are limited. A field experiment was carried out to evaluate the effects of humic acid on corn leaf burn caused by foliar spray of undiluted UAN solution on corn canopy at Jackson, TN in 2018. Thirteen treatments of the mixtures of UAN and humic acid were evaluated at V6 of corn with different UAN application rates and different UAN/humic acid ratios. Leaf burn during 1 2, 3, 4, 5, 6, 7, and 14 days after UAN foliar spray significantly differed between with or without humic acid addition. The addition of humic acid to UAN significantly reduced leaf burn at each UAN application rate (15, 25, and 35 gal/acre). The reduction of leaf burn was enhanced as the humic acid/UAN ratio went up from 10% to 30%. Leaf burn due to foliar application of UAN became severer with higher UAN rates. The linear regression of leaf burn 14 days after application with humic acid/UAN ratio was highly significant and negative. However, the linear regression of leaf burn 14 days after application with the UAN application rate was highly significant and positive. In conclusion, adding humic acid to foliar-applied UAN is beneficial for reducing corn leaf burn during the early growing season. 展开更多
关键词 Humic acid Urea-Ammonium Nitrate CORN Leaf Burn N rate ratio
下载PDF
Preparation and Characterization of Thermoplastic Starch from Sugar Palm (Arenga pinnata) by Extrusion Method 被引量:1
5
作者 Muhammad Ghozali Yenny Meliana +2 位作者 Widya Fatriasari Petar Antov Mochamad Chalid 《Journal of Renewable Materials》 SCIE EI 2023年第4期1963-1976,共14页
Sugar palm(Arenga pinnata)starch is considered an important renewable,biodegradable,and eco-friendly polymer,which is derived from agricultural by-products and residues,with great potential for the development of bioc... Sugar palm(Arenga pinnata)starch is considered an important renewable,biodegradable,and eco-friendly polymer,which is derived from agricultural by-products and residues,with great potential for the development of biocomposite materials.This research was aimed at investigating the development of TPS biocomposites from A.pinnata palm starch using an extrusion process.Palm starch,glycerol,and stearic acid were extruded in a twin-screw extruder.Scanning electron microscopy(SEM)analysis of TPS showed that the starch granules were damaged and gelatinized in the extrusion process.The density of TPS was 1.3695 g/mL,lower than that of palm starch,and the addition of stearic acid resulted in increased TPS density.X-ray diffraction(XRD)results showed that palm starch had a C-type pattern crystalline structure.The tensile strength,elongation at break,and modulus of elasticity of TPS were 7.19 MPa,33.95%,and 0.56 GPa,respectively.The addition of stearic acid reduced the tensile strength,elongation at break and modulus of elasticity of TPS.The rheological properties,i.e.,melt flow rate(MFR)and viscosity of TPS,were 7.13 g/10 min and 2482.19 Pa.s,respectively.The presence of stearic acid in TPS resulted in increased MFR and decreased viscosity values.The peak gelatinization temperature of A.pinnata palm starch was 70°C,while Tg of TPS was 65°C.The addition of stearic acid reduced the Tg of TPS.The thermogravimetric analysis(TGA)analysis showed that the addition of glycerol and stearic acid decreased the thermal stability,but extended the temperature range of thermal degradation.TPS derived from A.pinnata palm starch by extrusion method has the potential to be applied in industrial practice as a promising raw material for manufacturing bio-based packaging as a sustainable and green alternative to petroleum-based plastics. 展开更多
关键词 Arenga pinnata sugar palm starch thermoplastic starch GLYCEROL stearic acid twin-screw extruder BIOCOMPOSITES
下载PDF
Changes in Nib Acidity, Proteolysis and Sugar Concentration as Influenced by Pod Storage and Roasting Conditions of Fermented Cocoa (Theobroma cacao) Beans
6
作者 Eric Ofosu-Ansah Agnes Simpson Budu +2 位作者 Henry Mensah-Brown Jemmy Felix Takrama Emmanuel OheneAfoakwa 《Journal of Food Science and Engineering》 2013年第12期635-647,共13页
关键词 总糖含量 焙烧条件 酸度 可可 笔尖 蛋白水解 发酵 蛋白质含量
下载PDF
Effects of Exogenous Trehalose on the Metabolism of Sugar and Abscisic Acid in Tomato Seedlings Under Salt Stress 被引量:4
7
作者 Yanchun Feng Xiuyu Chen +2 位作者 Yulong He Xiaohong Kou Zhaohui Xue 《Transactions of Tianjin University》 EI CAS 2019年第5期451-471,共21页
Salt stress a ects the growth and development of plants, which results in a decrease in crop quality and yield. In this study, we used tomato seedlings treated with salt and trehalose as experimental materials and ana... Salt stress a ects the growth and development of plants, which results in a decrease in crop quality and yield. In this study, we used tomato seedlings treated with salt and trehalose as experimental materials and analyzed them using the technique for order preference by similarity to ideal solution analysis to select the optimal trehalose concentration for treatment. We also determined the contents of sugar and abscisic acid (ABA) and detected the expression of genes involved in the metabolism of sugar and ABA by quantitative real-time PCR. Results showed that the optimal trehalose concentration was 2 mmol/L for tomato seedlings under salt stress. Exogenous trehalose decreased the starch content and increased the soluble sugar con- tent by a ecting the expression of genes related to the metabolism of starch and soluble sugar. Exogenous trehalose altered the accumulation and distribution of sugar by inducing the upregulation of sugar transporter genes. Furthermore, trehalose increased the ABA content to induce salt stress response by regulating the expression of genes related to the synthesis and metabolism of ABA. In conclusion, trehalose can e ectively alleviate salt stress and enhance salt tolerance of tomato. These ndings provide a novel perspective and a better resource to investigate the salt tolerance mechanism and a new method for alleviating salt stress in tomato. 展开更多
关键词 tomato TREHALOSE Salt stress sugar METABOLISM sugar TRANSPORTER Abscisic acid
下载PDF
Oils with different degree of saturation:effects on ileal digestibility of fat and corresponding additivity and bacterial community in growing pigs
8
作者 Lu Wang Yifan Chen +2 位作者 Yuansen Yang Nuo Xiao Changhua Lai 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2024年第4期1657-1668,共12页
Background Oils are important sources of energy in pig diets.The combination of oils with different degree of saturation contributes to improve the utilization efficiency of the mixed oils and may reduce the cost of o... Background Oils are important sources of energy in pig diets.The combination of oils with different degree of saturation contributes to improve the utilization efficiency of the mixed oils and may reduce the cost of oil supplemented.An experiment was conducted to evaluate the effects of oils with different degree of saturation on the fat digestibility and corresponding additivity and bacterial community in growing pigs.Methods Eighteen crossbred(Duroc×Landrace×Yorkshire)barrows(initial body weight:29.3±2.8 kg)were surgically fitted with a T-cannula in the distal ileum.The experimental diets included a fat-free basal diet and 5 oil-added diets.The 5 oil-added diets were formulated by adding 6%oil with different ratio of unsaturated to saturated fatty acids(U:S)to the basal diet.The 5 oils were palm oil(U:S=1.2),canola oil(U:S=12.0),and palm oil and canola oil were mixed in different proportions to prepare a combination of U:S of 2.5,3.5 and 4.5,respectively.Results The apparent and standardized ileal digestibility(AID and SID)of fat and fatty acids increased linearly(P<0.05)as the U:S of dietary oils increased except for SID of fat and C18:2.The AID and SID of fat and fatty acids differed among the dietary treatments(P<0.05)except for SID of unsaturated fatty acids(UFA)and C18:2.Fitted one-slope broken-line analyses for the SID of fat,saturated fatty acids(SFA)and UFA indicated that the breakpoint for U:S of oil was 4.14(R^(2)=0.89,P<0.01),2.91(R^(2)=0.98,P<0.01)and 3.84(R^(2)=0.85,P<0.01),respectively.The determined SID of fat,C18:1,C18:2 and UFA in the mixtures was not different from the calculated SID of fat,C18:1,C18:2 and UFA.However,the determined SID of C16:0,C18:0 and SFA in the mixtures were greater than the calculated SID values(P<0.05).The abundance of Romboutsia and Turicibacter in pigs fed diet containing palm oil was greater than that in rapeseed oil treatment group,and the two bacteria were negatively correlated with SID of C16:0,C18:0 and SFA(P<0.05).Conclusions The optimal U:S for improving the utilization efficiency of mixed oil was 4.14.The SID of fat and UFA for palm oil and canola oil were additive in growing pigs,whereas the SID of SFA in the mixture of two oils was greater than the sum of the values of pure oils.Differences in fat digestibility caused by oils differing in degree of saturation has a significant impact on bacterial community in the foregut. 展开更多
关键词 ADDITIVITY Bacterial community Fat and fatty acids Growing pigs ratio of unsaturated to saturated fatty acids Standardized ileal digestibility
下载PDF
Preparation of activated carbon from sunflower straw through H_(3)PO_(4) activation and its application for acid fuchsin dye adsorption 被引量:1
9
作者 Wen-de Zhao Li-ping Chen Yan Jiao 《Water Science and Engineering》 EI CAS CSCD 2023年第2期192-202,共11页
With the development circular economy, the use of agricultural waste to prepare biomass materials to remove pollutants has become a research hotspot. In this study, sunflower straw activated carbon (SSAC) was prepared... With the development circular economy, the use of agricultural waste to prepare biomass materials to remove pollutants has become a research hotspot. In this study, sunflower straw activated carbon (SSAC) was prepared by the one-step activation method, with sunflower straw (SS) used as the raw material and H3PO4 used as the activator. Four types of SSAC were prepared with impregnation ratios (weight of SS to weight of H3PO4) of 1:1, 1:2, 1:3, and 1:5, corresponding to SSAC1, SSAC2, SSAC3, and SSAC4, respectively. The adsorption process of acid fuchsin (AF) in water using the four types of SSAC was studied. The results showed that the impregnation ratio significantly affected the structure of the materials. The increase in the impregnation ratio increased the specific surface area and pore volume of SSAC and improved the adsorption capacity of AF. However, an impregnation ratio that was too large led to a decrease in specific surface area. SSAC3, with an impregnation ratio of 1:3, had the largest specific surface area (1 794.01 m2/g), and SSAC4, with an impregnation ratio of 1:5, exhibited the smallest microporosity (0.052 7 cm3/g) and the largest pore volume (2.549 cm3/g). The adsorption kinetics of AF using the four types of SSAC agreed with the quasi-second-order adsorption kinetic model. The Langmuir isotherm model was suitable to describe SSAC3 and SSAC4, and the Freundlich isotherm model was appropriate to describe SSAC1 and SSAC2. The result of thermodynamics showed that the adsorption process was spontaneous and endothermic. At 303 K, SSAC4 showed a removal rate of 97.73% for 200-mg/L AF with a maximum adsorption capacity of 2 763.36 mg/g, the highest among the four types of SSAC. This study showed that SAAC prepared by the H3PO4-based one-step activation method is a green and efficient carbon material and has significant application potential for the treatment of dye-containing wastewater. 展开更多
关键词 acid fuchsin Activated carbon Adsorption Sunflower straw Phosphoric acid activation Impregnation ratio
下载PDF
Lateral root elongation in maize is related to auxin synthesis and transportation mediated by N metabolism under a mixed NO_(3)^(–) and NH_(4)^(+) supply
10
作者 Peng Wang Lan Yang +4 位作者 Xichao Sun Wenjun Shi Rui Dong Yuanhua Wu Guohua Mi 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第3期1048-1060,共13页
A mixed nitrate (NO_(3)^(–)) and ammonium (NH_(4)^(+)) supply can promote root growth in maize (Zea mays),however,the changes in root morphology and the related physiological mechanism under different N forms are sti... A mixed nitrate (NO_(3)^(–)) and ammonium (NH_(4)^(+)) supply can promote root growth in maize (Zea mays),however,the changes in root morphology and the related physiological mechanism under different N forms are still unclear.Here,maize seedlings were grown hydroponically with three N supplied in three different forms (NO_(3)^(–)only,75/25 NO_(3)^(–)/NH_(4)^(+)and NH_(4)^(+)only).Compared with sole NO_(3)^(–)or NH_(4)^(+),the mixed N supply increased the total root length of maize but did not affect the number of axial roots.The main reason was the increased total lateral root length,while the average lateral root (LR) length in each axle was only slightly increased.In addition,the average LR density of 2nd whorl crown root under mixed N was also increased.Compared with sole nitrate,mixed N could improve the N metabolism of roots (such as the N influx rate,nitrate reductase (NR) and glutamine synthase (GS)enzyme activities and total amino content of the roots).Experiments with exogenously added NR and GS inhibitors suggested that the increase in the average LR length under mixed N was related to the process of N assimilation,and whether the NR mediated NO synthesis participates in this process needs further exploration.Meanwhile,an investigation of the changes in root-shoot ratio and carbon (C) concentration showed that C transportation from shoots to roots may not be the key factor in mediating lateral root elongation,and the changes in the sugar concentration in roots further proved this conclusion.Furthermore,the synthesis and transportation of auxin in axial roots may play a key role in lateral root elongation,in which the expression of ZmPIN1B and ZmPIN9 may be involved in this pathway.This study preliminarily clarified the changes in root morphology and explored the possible physiological mechanism under a mixed N supply in maize,which may provide some theoretical basis for the cultivation of crop varieties with high N efficiency. 展开更多
关键词 MAIZE NO_(3)^(–)/NH_(4)^(+)ratio lateral root elongation N assimilation indole-3-acetic acid
下载PDF
Biosynthesis of ^(13)C-Labeled Amino Acids and Sugars by Spirulina (Arthrospira) Maxima in a Parallelepiped Photobioreactor
11
作者 夏金兰 聂珍媛 J.M.Levert 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2002年第5期102-106,共5页
This paper presents the investigation on biosynthesis of high-value-added amino acids and sugars labeled uniformly with stable isotope 13C by microalga Spirulina (Arthrospira) maxima in a parallelepiped photobioreacto... This paper presents the investigation on biosynthesis of high-value-added amino acids and sugars labeled uniformly with stable isotope 13C by microalga Spirulina (Arthrospira) maxima in a parallelepiped photobioreactor. The kinetic data of both batch and continuous cultures with characterization of the amino acids and sugars are shown. The continuous culture without nutrients deficiency is for biosynthesis of amino acids, with tyrosine as one of the principal constituents, and the batch culture with deficiency in nitrogen is for biosynthesis of labeled glucose that is up to 64% versus dry mass of cells. 展开更多
关键词 amino acid MICROALGA parallelepiped PHOtoBIOREACtoR SPIRULINA (Arthrospira) MAXIMA 13C-labeled sugar
全文增补中
Physiological Responses of Pea Plants to Salinity and Gibberellic Acid
12
作者 Houneida Attia 《Phyton-International Journal of Experimental Botany》 SCIE 2023年第1期149-164,共16页
Pea is a seed legume.It is rich in cellulose fibre and protein.It is also a significant source of minerals and vitamins.In this paper,we set out to better characterize the physiological responses of Pisum sativum L.to... Pea is a seed legume.It is rich in cellulose fibre and protein.It is also a significant source of minerals and vitamins.In this paper,we set out to better characterize the physiological responses of Pisum sativum L.to the combined effects of NaCl,100 mM and gibberellins(GA3).Our analysis revealed that NaCl caused a decrease in growth resulting in a reduction in root elongation,distribution and density,leaf number and leaf area,and a decrease in dry matter of roots and shoots.However,the contribution of GA3 in the salty environment induced an increase in these different parameters suggesting an improving effect of this hormone on growth of pea in presence of salt.NaCl also led to a disturbance of the photosynthetic machinery.Indeed,level of chlorophyll pigments(a and total)and photosynthetic activity were decreased compared to the control plants.However,the exogenous supply of GA3 restored this decrease in net CO_(2) assimilation,but not in chlorophyll content.Additional analyses were performed on the effect of salinity/GA3 interaction on osmolytes(soluble sugars and starch).Our results showed an increase in sugars and a decrease in starch in the presence of 100 mM NaCl.The salt-GA3 combination resulted in compensation of soluble sugar contents but not of starch contents,suggesting a beneficial effect of GA3 under saline stress conditions.Level of three main polyamines putrescine,spermidine,and spermine increased significantly in all organs of salt-treated plants. 展开更多
关键词 Pisum sativum L. SALINITY gibberellic acid GROWTH sugars polyamines
下载PDF
Synthesis of a Macromer, MPEGAA, Used to Prepare an AMPS-modified Polyacrylic Acid Superplasticizer 被引量:9
13
作者 CHEN Baofan 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2013年第6期1186-1190,共5页
A macromer, methoxypolyethylene glycol acrylate (MPEGAA), was synthesized by direct esterification using methoxypolyethylene glycol (MPEG-1200) and acrylic acid (AA) as the main materials. MPEGAA was then used t... A macromer, methoxypolyethylene glycol acrylate (MPEGAA), was synthesized by direct esterification using methoxypolyethylene glycol (MPEG-1200) and acrylic acid (AA) as the main materials. MPEGAA was then used to prepare a polyacrylic acid superplasticizer modified with 2-acrylamido-2- methylpropane sulfonic acid (AMPS). A single-factor test was performed to investigate the effects of the molar ratio of acid to alcohol (n(AA)/n(MPEG)), inhibitor amount, catalyst amount, temperature, and time of esterification on the synthesis of MPEGAA. The experimental results showed that the optimal esterification conditions were as follows: n(AA)/n(MPEG), 3.5:1; amount of hydroquinone (as an inhibitor), 1.2%; amount of para-toluenesulfonic acid (as a catalyst), 5.5%; reaction temperature, 95 ~C; and reaction time, 6 h. The AMPS- modified polyacrylic acid superplasticizer prepared under the optimal esterification conditions enabled the achievement and maintenance of high cement dispersibility. At an admixture amount of 0.15%, the cement paste fluidity was initially as high as 300 mm, and then decreased to 315 mm after 1 h and to 290 mm after 2 h. 展开更多
关键词 AMPS-modified polyacrylic acid superplasticizer esterification reaction macromer esterification ratio
下载PDF
Evaluation of sugar and organic acid composition and their levels in highbush blueberries from two regions of China 被引量:8
14
作者 ZHANG Jia NIE Ji-yun +5 位作者 LI Jing ZHANG Hui LI Ye Saqib FAROOQ Syed Asim Shah BACHA WANG Jie 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2020年第9期2352-2361,共10页
Sweet and sour are the most important taste of blueberries,and they are produced by sugar and acid,respectively.Their contributions to the taste depend not only on the levels of sugar and acid,but also on the types an... Sweet and sour are the most important taste of blueberries,and they are produced by sugar and acid,respectively.Their contributions to the taste depend not only on the levels of sugar and acid,but also on the types and relative proportions of sugar and acid.Therefore,it is very important to evaluate the composition and levels of sugar and acid in blueberries.Regional differences and variety diversity also affect the sugar and acid characteristics of fruits.Therefore,this study selected two main producing regions in northern China(Weihai and Yingkou)to examine the sugar and acid characteristics of 11 common blueberry cultivars.The indexes measured included soluble sugars,organic acids,soluble solid content and titratable acidity.The results showed that glucose and fructose were the major sugars,and citric acid and quinic acid were the major organic acids.Correlation analysis showed that glucose,fructose,and sucrose were positively correlated with total sugar content;the citric acid content was positively correlated with the titratable acidity and total organic acids.Titratable acidity,glucose,fructose,sucrose,total sugar content,citric acid,shikimic acid and total acid content of the blueberries varied significantly between regions(P<0.05).In general,compared with Weihai blueberries,Yingkou blueberries had higher sugar content and lower acid content.The results of this study may provide useful references for the evaluation of sweet and sour flavors and cultivar selection of blueberries. 展开更多
关键词 BLUEBERRY sugar organic acid level EVALUATION
下载PDF
Effect of Starch/Polylactic Acid Ratio on the Interdependence of Two-Phase and the Properties of Composites 被引量:3
15
作者 左迎峰 GU Jiyou +3 位作者 CAO Jun WEI Shuangying TAN Haiyan 张彦华 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2015年第5期1108-1114,共7页
Starch/polylactic acid(PLA) composites were prepared by melt extrusion, with corn starch and PLA as raw materials, glycerol as the plasticizer. Effects of starch/PLA ratio on the interdependence of two-phase and other... Starch/polylactic acid(PLA) composites were prepared by melt extrusion, with corn starch and PLA as raw materials, glycerol as the plasticizer. Effects of starch/PLA ratio on the interdependence of two-phase and other properties of the composites were studied. The combination of results of TGA with SEM indicated that the interdependence between starch and PLA was increased gradually as the starch/PLA ratio reduced. DSC results showed that the glass transition temperature(Tg), melting temperature(Tm) and degree of crystallinity of PLA in composites were increased gradually, whereas the cold crystallization temperature(Tc) was gradually decreased as the starch/PLA ratio reduced. The rheological properties of composites were closely related with the interdependence of two-phase, with reducing starch/PLA proportion, the interdependence was increased, and then the strain for storage modulus was firstl reduced and then gradually increased. Frequency scanning showed that the storage modulus and complex viscosity were decreased with reducing starch content. As the starch/PLA ratio reduced, the matrix phase PLA was increased, so that the strength of composites was increased gradually, whereas water absorption rate was decreased gradually. 展开更多
关键词 corn starch polylactic acid mixing ratio interdependence of two-phase PROPERTIES
下载PDF
High Performance Liquid Chromatography Analysis of Sugars and Acid Components in ’Xintai Tianhong’ Hawthorn Fruit 被引量:1
16
作者 Shuwei WEI Shaomin WANG 《Agricultural Biotechnology》 CAS 2019年第4期163-164,共2页
[Objectives]This study was conducted to provide basic information for the utilization,quality control and deep processing of‘Xintai Tianhong’hawthorn fruit resources.[Methods]The contents of sugar and acid component... [Objectives]This study was conducted to provide basic information for the utilization,quality control and deep processing of‘Xintai Tianhong’hawthorn fruit resources.[Methods]The contents of sugar and acid components in‘Xintai Tianhong’hawthorn fruit were determined by high performance liquid chromatography(HPLC).[Results]‘Xintai Tianhong’hawthorn fruit contained such four kinds of sugar components as fructose,sorbitol,glucose and sucrose,and such six kinds of organic acid components as oxalic acid,tartaric acid,malic acid,acetic acid,citric acid and succinic acid.The fruit had the highest sucrose content,accounting for 70.53%of the total sugar content,followed by fructose,glucose and sorbitol.For the organic acid components,the content of succinic acid was the highest,accounting for 47.32%of the total acid content,followed by citric acid,malic acid,oxalic acid and tartaric acid,and acetic acid had the lowest content.[Conclusions]‘Xintai Tianhong’hawthorn should be a succinic acid-type hawthorn variety,which can be used as a parent in genetic research and breeding practice. 展开更多
关键词 High performance liquid CHROMAtoGRAPHY HAWTHORN sugar Organic acid
下载PDF
Effect of Altering Linoleic Acid and Linolenic Acid Dietary Ratios on the Performance and Tissue Fatty Acid Profiles of Prawn, Macrobrachium rosenbergii (de Man 1879) Post Larvae 被引量:11
17
作者 A. M. A. S. Goda M. M. Habashy +5 位作者 M. A. Hanafy R. A. Mohamed H. A. Mabrouk T. M. El-Afifi S. A.Nada K. A. Mohamed 《Journal of Agricultural Science and Technology(B)》 2011年第7期1032-1044,共13页
关键词 脂肪酸组成 罗氏沼虾 生长性能 亚麻酸 亚油酸 组织 膳食 幼虫
下载PDF
Sugar and Acid Content and Their Genotypic Correlations of Unselected P.persica x P.davidiana Progenies as Affected by Hairness and Flesh Color
18
作者 WUBen-hong LIShao-hua +2 位作者 QuilotBenedicte GenardMichel KervellaJocelyne 《Agricultural Sciences in China》 CAS CSCD 2004年第2期136-142,共7页
Fruit sugar and acid content were determined in a group of hybrids from one family,including 22 peach and 85 nectarine genotypes, or 75 white-fleshed and 32 yellow-fleshedgenotypes. Sucrose accounted for about 65% of ... Fruit sugar and acid content were determined in a group of hybrids from one family,including 22 peach and 85 nectarine genotypes, or 75 white-fleshed and 32 yellow-fleshedgenotypes. Sucrose accounted for about 65% of the total sugar, and malate for about 50%of the total acid. Mean sucrose, fructose, sorbitol, total sugar, soluble solid andquinate content were significantly higher in nectarines than in peaches, while nosignificant difference was found in mean malate, citrate and total acid content betweennectarines and peaches. Shikimate content was very low and ranged from 0.011-0.046 meq100 g-1 FW in all genotypes studied. Flesh color did not affect sugar and acid content.Glucose and fructose had a close positive correlation (r =0.63***). Malate had positivecorrelations with sucrose, sorbitol, total sugar and soluble solid content. The correlationbetween citrate and sugars were not significant. Glucose, fructose, sorbitol and malatecontent seemed to be higher in late-maturing genotypes. Sucrose, total sugar and totalacid content had a parabolic relationship with developmental period (from full bloomingdate to maturity date). 展开更多
关键词 acid Flesh color NECTARINE PEACH sugar
下载PDF
Compound-specific isotopes of fatty acids as indicators of trophic interactions in the East China Sea ecosystem
19
作者 吴莹 王娜 +3 位作者 张经 万瑞景 戴芳群 金显仕 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2016年第5期1085-1096,共12页
The composition and compound-specific isotopes of fatty acids were studied within food webs in the East China Sea.Lipid-normalized stable carbon isotopes of total organic carbon had a good correlation with trophic lev... The composition and compound-specific isotopes of fatty acids were studied within food webs in the East China Sea.Lipid-normalized stable carbon isotopes of total organic carbon had a good correlation with trophic level.Variations in fatty acid compositions among different species were observed but were unclear.Different dietary structures could be traced from molecular isotopes of selected fatty acids in the Shiba shrimp(Matapenaeus joyneri),the coastal mud shrimp(Solenocera crassicomis) and the northern Maoxia shrimp(Acetes chinensis).Both M.joyneri and S.crassicomis are mainly benthos feeders,while A.chinensis is a pelagic species,although they have a similar fatty acid composition.There was a good correlation for isotopes of arachidonic acid(C20:4n6;ARA) and docosahexaenoic acid(C22:6n3;DHA)among pelagic species from higher trophic levels.The isotopic compositions of DHA in benthic species were more negative than those of pelagic species at the same trophic level.The fact that the diet of benthic species contains more degraded items,the carbon isotopes of which are derived from a large biochemical fraction,may be the reason for this variation.A comparative study of benthic and pelagic species demonstrated the different carbon sources in potential food items and the presence of a more complex system at the watersediment interface. 展开更多
关键词 fatty acid compound-specific isotope ratio stable isotope ratio East China Sea
下载PDF
The Relationships between Erythrocyte Membrane n-6 to n-3 Polyunsaturated Fatty Acids Ratio and Blood Lipids and C-reactive Protein in Chinese Adults:An Observational Study
20
作者 ZHANG Bo WANG Ping +6 位作者 ZHOU Quan CHEN ChaoGang ZHUO ShuYu YE YanBin HE QiQiang CHEN YuMing SU YiXiang 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2011年第3期234-242,共9页
Objective To investigate the relationships between erythrocyte membrane n-6:n-3 PUFAs ratio and blood lipids and high sensitivity C-reactive protein (hs-CRP). Methods The Chinese and a observational study consisted... Objective To investigate the relationships between erythrocyte membrane n-6:n-3 PUFAs ratio and blood lipids and high sensitivity C-reactive protein (hs-CRP). Methods The Chinese and a observational study consisted of a population-based cross-sectiona subsequent 1-year follow-up study of 171 subjects with the fasting cholesterol of 5.13-8.00 mmol/L. study of 456 plasma total Results In the cross-sectional analysis, plasma low-density lipoprotein cholesterol (LDL-c) had a significant and negative association with the erythrocyte membrane n-6:n-3 PUFAs ratio (P for trend=0.019) after adjusting for sex, age and total PUFA percentage. In the follow-up study, 171 subjects were categorized into quartiles by the changes of n-6:n-3 ratio in erythrocyte membrane (△=month 12-month 0). In the top quartile whose ratios of n-6:n-3 increased by an average of 1.25 during the follow-up, the LDL-c-lowering extent was 3.3 times of that in the lowest quartile whose ratios of n-6:n-3 decreased by an average of 1.13 (-1.07 mmol/L v.s. -0.32 mmol/L). The hsCRP decreased by 0.11 mg/dL in the lowest quartile while increasing by 0.10 mg/dL in the top quartile (P for difference=0.052). Conclusion Our results suggested that the balance between n-6 and n-3 fatty acids may optimize the cardiovascular benefits from dietary PUFAs. 展开更多
关键词 Erythrocyte membrane n-6:n-3 fatty acids ratio Blood lipids High sensitivity C-reactiveprotein Observational study
下载PDF
上一页 1 2 168 下一页 到第
使用帮助 返回顶部