[Objectives]This study was conducted to optimize the extraction process of Sipunculus nudus polysaccharide and study the antioxidant activity of S. nudus polysaccharide. [Methods] S. nudus polysaccharide was extracted...[Objectives]This study was conducted to optimize the extraction process of Sipunculus nudus polysaccharide and study the antioxidant activity of S. nudus polysaccharide. [Methods] S. nudus polysaccharide was extracted by ultrasonic microwave assisted method,during which univariate factors including solidliquid ratio,time,temperature,ultrasonic power,microwave power were investigated,to select optimal extracting conditions,which were also verified by an response surface optimization experiment( an four-factor three-level test); and the antioxidant activity of S. nudus polysaccharide was studied by determining its DPPH radical scavenging capacity. [Results]Through univariate factor investigation and response surface optimization test,it was found that the response surface results were consistent with univariate results. The optimized conditions were as follows: solid-liquid ratio at 1∶ 15,ultrasonic temperature at 60 ℃,ultrasonic power of 360 W and microwave power of 200 W,and the predicted polysaccharide extracting amount was 4. 35 mg/g. Under the optimized extracting conditions,the average extracting amount of S. nudus polysaccharide was 4. 38 mg/g,which is close to the theoretical predicted value( 4. 35 mg/g). And the results of this study also showed that different concentrations of polysaccharide solutions have different scavenging effects on DPPH free radical. At the polysaccharide concentration of0. 16 mg/ml,the maximum value of DPPH radical scavenging rate was 7. 22%,indicating that polysaccharide has certain antioxidant capacity. [Conclusions]This method is a new trial with satisfactory results.展开更多
[Objectives] This study was conducted to optimize the determination conditions of amino acids from abalone. [Methods] The sample was treated by acid hydrolysis method and subjected to 2,4-2 nitro fluorobenzene column ...[Objectives] This study was conducted to optimize the determination conditions of amino acids from abalone. [Methods] The sample was treated by acid hydrolysis method and subjected to 2,4-2 nitro fluorobenzene column derivatization. The amino acid content in abalone was determined by HLPC,and the nutritional value of the amino acids was evaluated with egg protein model put forward by Institute of Nutrition and Food Hygiene,Chinese Academy of Preventive Medicine. [Results] Abalone contains full amino acids. According to the FAO/WHO ideal,it is a high-quality protein source and suitable for supplement of protein source for human body. [Conclusions]The experimental method has simple operation and could achieve a good effect with wide linear range and correlation coefficient over 0. 999 8,and the obtained results are satisfactory.展开更多
[Objectives] This study was conducted to optimize the extraction process of protocatechuic acid from Emilia sonchifolia DC. [Methods] The optimal extraction conditions were determined by single factor,response surface...[Objectives] This study was conducted to optimize the extraction process of protocatechuic acid from Emilia sonchifolia DC. [Methods] The optimal extraction conditions were determined by single factor,response surface analysis and variance analysis,and the content of protocatechuic acid was determined by HPLC. [Results] The protocatechuic acid standard curve equation was: y = 1 435 x + 8 403,R^2= 0. 999 8,indicating a good linear relationship. The optimal extraction conditions were as follows: a temperature at 80 ℃,an extraction time of 1 h,a material-to-liquid ratio at 1:10 and an ultrasonic power of 600 W,and the content of protocatechuic acid extracted was 1. 93 mg/g. The method showed a RSD of 0. 41%,less than 2%,and the detection limit was 0. 0000047261 g/ml.The experimental sample X1 was the low-level 0. 1 mg/ml standard solution,which showed recovery of protocatechuic acid between 100.8% and 105.2%,with a RSD of 0. 013%;and the sample X2 was the high-level 1. 0 mg/ml standard solution,which exhibited recovery between 100. 6% and 102. 2%,with a RSD of 0.076%. Thus,the recovery was high,and the requirements of the performance index were met. [Conclusions] The detection method is stable and reliable and can produce satisfactory results.展开更多
[Objectives]The most common gene fragment used in animal DNA barcode technology is COI,but it is not necessarily suitable for all species.This study was conducted to screen genes suitable for the DNA barcode of sea sn...[Objectives]The most common gene fragment used in animal DNA barcode technology is COI,but it is not necessarily suitable for all species.This study was conducted to screen genes suitable for the DNA barcode of sea snakes.[Methods]All COI and cytb gene sequences on GenBank were searched and downloaded.After the comparison with Mega software,clustering trees of MrBayes system were established.[Results]Interspecies distances were greater than intraspecies distances for the two genes.The topological structures of their molecular hierarchical clustering trees were clear,and the support rates were high.[Conclusions]Therefore,it is concluded that not the DNA barcode of each species must be gene COI.Cytb is more suitable in terms of the mitochondrial gene of sea snakes.展开更多
[Objectives] The effects of copper-based nutrient foliar fertilizer on photosynthetic characteristics,yield,accumulation and distribution of trace elements in various organs,disease prevention effect and soil enzyme a...[Objectives] The effects of copper-based nutrient foliar fertilizer on photosynthetic characteristics,yield,accumulation and distribution of trace elements in various organs,disease prevention effect and soil enzyme activity were studied,so as to provide a theoretical basis for the application of foliar fertilizers in cotton production. [Methods]Through two years of field experiments,six treatments were set in total,namely spraying water( CK),traditional Bordeaux mixture( BDM),Kocide 2000( KCD),copper-based nutrient foliar fertilizer( CF),iron-copper-based nutrient foliar fertilizer( CFFe),and zinc-boron-copper-based nutrient foliar fertilizer( CFZnB). Randomized block arrangement was adopted. Chlorophyll content in leaves was measured at each growth stage of the cotton. Photosynthetic characteristics of leaves were measured at the peak bolling stage. Plants were sampled at initial boll opening stage. The whole plant was divided into root,stem,leaf and cotton boll parts,in which the total copper,total zinc,total iron contents and accumulations were determined. Soil samples were collected from each plot,followed by the determination of soil enzyme activity. Disease index was investigated at bud,flowering and boll-forming and boll opening stage. [Results]( 1) Spraying CFFe,CFZnB,CF and KCD could significantly improve chlorophyll content of cotton leaves,and the CFFe treatment had the highest increase up to13. 30%,followed by the CFZnB treatment,which was 11. 40% higher than the CK; and photosynthetic rate,stomata conductance and transpiration rate could be improved significantly,and the CFFe treatment showed the highest photosynthetic rate,which increased by 26. 35% compared with the CK,followed by the CFZnB treatment,which increased by 17. 96% compared with CK; and intercellular CO2 concentration was significantly reduced.( 2) Spraying BDM,KCD,CF,CFFe and CFZnB can significantly increase total copper content and accumulation in various cotton organs( except the total copper content in the stem part of the CFZnB treatment; the CFZnB and CFFe treatments can significantly increase total zinc content and accumulation in various cotton organs; and spraying CFFe,CFZnB and CF can significantly increase total iron content and accumulation in various cotton organs( except the total iron content in the stem part of the CF treatment).( 3)Spraying CFFe,CFZnB,CF,KCD and BDM greatly reduced the disease index at flowering and boll-forming and boll opening stages.( 4) The CFZnB and CFFe treatments had the highest soil urease activity,which was 7. 14% higher than that of the CK,but the difference from the CK was not significant; the catalase activity of each treatment was significantly higher than that of the BDM treatment; and the sucrase activity of each treatment was significantly higher than that of the CK.( 5) Spraying CFFe,CFZnB,CF and KCD significantly improved lint yield of cotton,and the CFZnB treatment showed the highest yield increase up to 12. 34%,followed by the CFFe treatment,with an increase in the range of 8. 77%-10. 20%. [Conclusions]Copper-based nutrient foliar fertilizers have dual functions of disease control and prevention and plant nutrition and health care,and not only can significantly increase cotton yield,but also has certain disease prevention effect.It is recommended to use copper-based nutrient foliar fertilizers.展开更多
[ Objective ] This study aimed to investigate the impacts of different instruments and methods on detection of water samples and evaluate the detection results and pollution share rate. [ Method] Concentrations of six...[ Objective ] This study aimed to investigate the impacts of different instruments and methods on detection of water samples and evaluate the detection results and pollution share rate. [ Method] Concentrations of six heavy metals in three surface water samples and three underground water samples were detected by AAS and ICP-AES to analyze the differences in detection results and calculate the pollution share rate of heavy metals. [Result] As a result, the pollution share rate of six heavy metals varied significantly. Calculation results of comprehensive pollution share rate based on the lower pollution index of the same heavy metal in the same water sample detected by two methods were different from the results using either method. Due to different detection limits of instruments, detection results of heavy metals in the same water sample were different, which affected the accuracy of environmental quality assessment. [ Conclusion ] The detected pollution share rate varies with different detection limits. Therefore, instruments and methods with lower detection limit should be used. To be specific, AAS is suitable for detection of Pb and Cd, while ICP is suitable for detection of Cu, Zn, Fe and Mn.展开更多
[Objectives]This study was conducted to optimize the extraction process of Sipunculus nudus polysaccharide.[Methods]S.nudus polysaccharide was extracted by ultrasonic water extraction,with the marine S.nudus as a raw ...[Objectives]This study was conducted to optimize the extraction process of Sipunculus nudus polysaccharide.[Methods]S.nudus polysaccharide was extracted by ultrasonic water extraction,with the marine S.nudus as a raw material from Sanya City,Hainan Province,by single factor variable method,to find the optimal extraction conditions including ultrasonic power,solid-liquid ratio,ultrasonic extraction temperature,ultrasonic extraction time,ultrasonic extraction times and lye concentration.The absorbance of the polysaccharide was determined by an ultraviolet spectrophotometer,and polysaccharide yield were calculated.The antioxidant activity of scavenging hydroxyl and DPPH radicals was measured at different concentrations.[Results]The optimal extraction conditions for S.nudus polysaccharide were as follows:solid-liquid ratio at 1∶11 mg/ml,extraction temperature at 60℃,three times of ultrasonic extraction,ultrasonic power of 960 W,extraction time of 1.5 h,and lye concentration of 5%,under which the polysaccharide yield was 3.21%.The scavenging rates of hydroxyl radical and DPPH radical were 12.58%at the concentration of 0.20 mg/ml.Moreover,the scavenging rates increased significantly with the increase of concentration.[Conclusions]This method is a new trial with satisfactory results.展开更多
A rapid and sensitive liquid chromatographyetandem mass spectrometry method was developed and validated for the quantification of cyclobenzaprine in dog plasma.After extracted with organic solvent,post-treatment sampl...A rapid and sensitive liquid chromatographyetandem mass spectrometry method was developed and validated for the quantification of cyclobenzaprine in dog plasma.After extracted with organic solvent,post-treatment samples were separated on an Agela C18 column interfaced with a triple quadrupole tandem mass spectrometer in positive electrospray ionization mode.Multiple reaction monitoring was performed using the transitions of m/z 276.2/216.1 and m/z 325.1/109.0 to quantify cyclobenzaprine and escitalopram(internal standard),respectively.The mobile phase consisted of acetonitrile:5 mM ammonium acetate:formic acid(90:10:0.01,v/v/v)at a flow rate of 0.3 ml/min.The total analysis time was 2.4 min.The method was linear over the concentration range of 0.0200e10.0 ng/ml.The intra-and inter-day precision was within 12.8%in terms of relative standard deviation(RSD%)and the accuracy within 5.6%in terms of relative error.This method was successfully applied in a pharmacokinetic study of extended-release cyclobenzaprine in dogs.展开更多
[Objectives] This study was conducted to further investigate the taxonomic status of Hainan population of Trimeresurus stejnegeri from the morphological point of view.[Methods]The difference coefficients between diffe...[Objectives] This study was conducted to further investigate the taxonomic status of Hainan population of Trimeresurus stejnegeri from the morphological point of view.[Methods]The difference coefficients between different populations were compared using the 75% law,and the relationship between scales and latitudes was analyzed.[Results] The scales(abdominal and subcaudal) of 325 Trimeresurus individuals were counted according to China Animal Fauna,including156 T.stejnegeri individuals.Some difference coefficients between the Hainan population and others were greater than 1.28,and there was no correlation between the number of scales and latitude.It conforms to subclassification criteria.[Conclusions]The view about the subspecies status of T.stejnegeri chenbihuii should be supported.展开更多
[Objectives] This study was conducted to optimize experimental conditions for extraction of polysaccharides from Sipunculus nudus.[Methods]With the Sipunculus nudus from Sanya as the experimental material,S.nudus poly...[Objectives] This study was conducted to optimize experimental conditions for extraction of polysaccharides from Sipunculus nudus.[Methods]With the Sipunculus nudus from Sanya as the experimental material,S.nudus polysaccharide was extracted by ultrasonic microwave assisted method,during which univariate factors including solid-liquid ratio,time,temperature,ultrasonic power,microwave power were investigated,to select optimal extracting conditions,which were also demonstrated and optimized by variance and response surface analysis.The optimized conditions were adopted to carry out a test,in which the absorbance of S.nudus polysaccharide was measured with an ultraviolet and visible spectrophotometer,followed by the calculation of the extracting amount of polysaccharide,and precision test and recovery test were also carried out to verify the experimental method.[Results]The standard solutions were determined at the maximum absorption wavelength of 486 nm,and the regression equation was A = 0.2677 C + 0.001 8,R^2= 0.999 8.Solid-liquid ratio,time,temperature,ultrasonic power and microwave power were investigated by univariate analysis and then optimized by response surface method as follows: solid-liquid ratio at 1:20( g/ml),time of 35 min,temperature at 50 ℃,ultrasonic power at 420 W and microwave power at 300 W,under which the measured extracting amount of S.nudus polysaccharide was1.37 mg/g.The RSD was 0.985% in precision experiment.In the repeatability test,the extracting amounts of polysaccharide were 1.41,1.43 and 1.38 mg/g for three parallel tests,respectively,with a RSD of 1.140%.The recovery test obtained following results: for group a( added with glucose standard) : the recovery of S.nudus polysaccharide was in the range of 100.3%-101.4%,RSD = 0.03%; and for group b( not added with glucose standard) : the recovery of S.nudus polysaccharide was in the range of 99.7%-100.3%,RSD = 0.02%.[Conclusions]The research method is stable and reliable.This study provides data basis and reference for follow-up study on S.nudus.展开更多
According to the contradictions about classification on Trimeresurus between ＂China＇s Fauna＂ and international database, the rationality about Trimeresurus divided to multiple genera based on molecular systematies ...According to the contradictions about classification on Trimeresurus between ＂China＇s Fauna＂ and international database, the rationality about Trimeresurus divided to multiple genera based on molecular systematies was discussed. The genetic distance was calculated by sequencing 12S gene of the original Trimeresurus snakes, including 80 individuals of 33 species ; and the molecular phylogenetie tree was established by taking Hypnale hypnale as the outgroup. The results showed that the topological structures of ME tree and ML tree were basically consistent, and all of the species in the molecular trees were divided into 8 branches; and the difference of T. albolabris between Hainan and other locations is not obvious. The viewpoint that original Trimeresurus genera subdivided into 8 genera was more rational, and new authoritative reference books are expected to be published in China.展开更多
The contents of five kinds of fatty acids(palmitic acid,stearic acid,oleic acid,linoleic acid and linolenic acid)in 56 collected peanut(Arachis hypogaea Linn.)varieties were determined by gas chromatography.The result...The contents of five kinds of fatty acids(palmitic acid,stearic acid,oleic acid,linoleic acid and linolenic acid)in 56 collected peanut(Arachis hypogaea Linn.)varieties were determined by gas chromatography.The results showed that in the 56 peanut varieties,oleic acid content was in the range of 36.859%-67.093%;linoleic acid content was in the range of 14.122%-61.025%;palmitic acid content was in the range of 8.583%-20.286%;stearic acid content was in the range of 2.442%-8.971%;and linolenic acid content was in the range of 0.028%-0.093%.Peanut samples No.9304,9355 and 9353 had higher oleic acid/linoleic acid(O/L)ratios,which were 4.751,3.623 and 3.049,respectively,while peanut sample No.9337 exhibited the lowest O/L value of 0.899.展开更多
As an important tropical cash crop,rubber trees play a key role in the rubber industry and ecosystem.However,a significant challenge in precision agriculture and refined management of rubber plantation lies in the lim...As an important tropical cash crop,rubber trees play a key role in the rubber industry and ecosystem.However,a significant challenge in precision agriculture and refined management of rubber plantation lies in the limitations of traditional point cloud segmentation methods,which struggle to accurately extract structural parameters and capture the spatial layout of individual rubber trees.Therefore,we propose an optimized dual-channel clustering method for the UAV LiDAR-based Rubber Tree Point Cloud Segmentation Network(RsegNet)for improved assessment of rubber tree architecture and traits.Firstly,we designed a cosine feature extraction network,termed CosineU-Net,to address the branch-and-leaf overlap problem by calculating the cosine similarity of the spatial and positional features of each point,leveraging deep learning approaches to improve feature representation.Secondly,we constructed a dual-channel clustering module reducing prediction error in rubber tree point cloud data,integrating multi-class association and background classification to tackle background interference.The cluster identification and separation accuracy in high-dimensional data processing is enhanced through a dy-namic clustering optimization algorithm.In our self-built dataset and across five regions of the FOR-instance forest dataset,RsegNet achieved the best performance compared to five state-of-the-art networks,reaching an F-score of 86.1%.This method calculated structural attributes including height,crown diameter,and volume for rubber trees in three areas under different environments in Danzhou City,Hainan Province,providing robust support for precise monitoring,plantation management,and health assessment.展开更多
Rubber products have become an important strategic resource in the global economy.However,individual rubber tree segmentation in plantation environments remains challenging due to canopy background interfer-ence and s...Rubber products have become an important strategic resource in the global economy.However,individual rubber tree segmentation in plantation environments remains challenging due to canopy background interfer-ence and significant morphological variations among trees.To address these issues,we propose a high-precision segmentation network,TM-WSNet(Spatial Geometry Enhanced Hybrid Feature Extraction Module-Wavelet Grid Feature Fusion Encoder Segmentation Network).First,we introduce SGTramba,a hybrid feature extraction module combining Grouped Transformer and Mamba architectures,designed to reduce confusion between tree crown boundaries and surrounding vegetation or background elements.Second,we propose the WGMS encoder,which enhances structural feature recognition by applying wavelet-based spatial grid downsampling and mul-tiscale feature fusion,effectively handling variations in canopy shape and tree height.Third,a scale optimization algorithm(SCPO)is developed to adaptively search for the optimal learning rate,addressing uneven learning across different resolution scales.We evaluate TM-WSNet on a self-constructed dataset(RubberTree)and two public datasets(ShapeNetPart and ForestSemantic),where it consistently achieves high segmentation accuracy and robustness.In practical field tests,our method accurately predicts key rubber tree parameters—height,crown width,and diameter at breast height with coefficients of determination(R^(2))of 1.00,0.99,and 0.89,respectively.These results demonstrate TM-WSNet's strong potential for supporting precision rubber yield estimation and health monitoring in complex plantation environments.展开更多
Let p≥7 be a prime.We prove thatβ_(p^(2)/p^(2)-1)survives to E_(∞)in the Adams-Novikov spectral sequence.Additionally,using the Thom mapΦ:■,we can see that h0h3 also survives to E_(∞)in the classical Adams spect...Let p≥7 be a prime.We prove thatβ_(p^(2)/p^(2)-1)survives to E_(∞)in the Adams-Novikov spectral sequence.Additionally,using the Thom mapΦ:■,we can see that h0h3 also survives to E_(∞)in the classical Adams spectral sequence.As an application of these results,we prove thatβ^(p)_(p/p)is divisible byβ_(1).展开更多
In this paper, the bacterial celluloses(BCs) were pyrolysed in nitrogen and then activated by KOH to form a porous three- dimension-network electrode material for supercapacitor applications. Activated pyrolysed bacte...In this paper, the bacterial celluloses(BCs) were pyrolysed in nitrogen and then activated by KOH to form a porous three- dimension-network electrode material for supercapacitor applications. Activated pyrolysed bacterial cellulose(APBC) samples with enlarged specific surface area and enhanced specific capacitances were obtained. In order to optimize electrochemical properties, APBC samples with different alkali-to-carbon ratios of 1, 2 and 3 were tested in two electrodes symmetrical capacitors. The optimized APBC sample holds the highest specific capacitance of 241.8 F/g, and the energy density of which is 5 times higher than that of PBC even at a current density of 5 A/g. This work presents a successful practice of preparing electrode material from environment-friendly biomass, bacterial cellulose.展开更多
In this paper,we study the topology of moment-angle manifolds and prove a conjecture of S.Gitler and S.Lopez de Medrano concerned with the behavior of the moment-angle manifold under the surgery’cutting off a vertex...In this paper,we study the topology of moment-angle manifolds and prove a conjecture of S.Gitler and S.Lopez de Medrano concerned with the behavior of the moment-angle manifold under the surgery’cutting off a vertex’on a simple polytope.Let P be a simple polytope of dimension n with m facets and Pv be a poly tope obtained from P by cutting off one vertex v.Let Z=Z(P)and Zv=Z(Pv)be the corresponding moment-angle manifolds.S.Gitler and S.Lopez de Medrano conjectured that:Zv is diffeomorphic to δ[(Z(-D^n+m)×D^2]##^m-n/j=1(m-n/j)(S^j+2×S^m+n-j-1),and they proved the conjecture in the case m<3 n.In this paper we prove the conjecture in the general case.展开更多
Existing studies about wind pressure on agricultural greenhouse buildings concentrate on the mean wind pressure while ignoring the systematic research on fluctuating wind pressure characteristics and the influence of ...Existing studies about wind pressure on agricultural greenhouse buildings concentrate on the mean wind pressure while ignoring the systematic research on fluctuating wind pressure characteristics and the influence of roof shape on the wind pressure characteristics,which are closely associated with the wind-induced damage mecha-nism.In this study,two typical agricultural greenhouse buildings on tropical islands are selected as prototypes to conduct pressure measurement experiments in the wind tunnel.Based on the wind pressure time series for the two greenhouses,the mean and fluctuating wind pressure distribution pattern and the localized high-pressure generation mechanism are analyzed.Then,the shape coefficient of the two green-houses is compared in depth to the standards from four countries.Besides,wind pressure non-Gaussian determination criteria for agricultural greenhouse buildings considering the roof shape and wind directions are proposed.Lastly,the differences in wind pressure spectra on the roofs and walls of the two greenhouses are sum-marized.The results indicate the roof shape has a significant influence on the wind pressure characteristics.Compared with the pitched roof,the vaulted roof will increase the suction effect on the windward front zone and the middle area,mitigate the suc-tion impact on the leeward roof,and weaken the wind pressure non-Gaussian charac-teristics.The experimental shape coefficient of the pitched-roof greenhouse is basically consistent with the standard from the U.S.,while that of the vaulted-roof greenhouse has some deviation from the existing standards.The results provide a theoretical basis for the wind-resistant design of agricultural greenhouse buildings on tropical islands.展开更多
The connected sum is a fundamental operation in geometric topology and combinatorics.In this paper,we study the connection between connected sums of simplicial spheres and the algebraic topology of their corresponding...The connected sum is a fundamental operation in geometric topology and combinatorics.In this paper,we study the connection between connected sums of simplicial spheres and the algebraic topology of their corresponding moment-angle manifolds.The cohomology rings of moment-angle manifolds corresponding to connected sums of simplicial spheres are computed,which leads to a conjecture on the topology of such moment-angle manifolds.展开更多
基金Supported by National Natural Science Foundation of Hainan Province(217157)2017 Provincial College Students' Innovation and Entrepreneurship Training Program(201711100005)2018 Provincial Key Discipline (Thalassochemistry) Construction Fund
文摘[Objectives]This study was conducted to optimize the extraction process of Sipunculus nudus polysaccharide and study the antioxidant activity of S. nudus polysaccharide. [Methods] S. nudus polysaccharide was extracted by ultrasonic microwave assisted method,during which univariate factors including solidliquid ratio,time,temperature,ultrasonic power,microwave power were investigated,to select optimal extracting conditions,which were also verified by an response surface optimization experiment( an four-factor three-level test); and the antioxidant activity of S. nudus polysaccharide was studied by determining its DPPH radical scavenging capacity. [Results]Through univariate factor investigation and response surface optimization test,it was found that the response surface results were consistent with univariate results. The optimized conditions were as follows: solid-liquid ratio at 1∶ 15,ultrasonic temperature at 60 ℃,ultrasonic power of 360 W and microwave power of 200 W,and the predicted polysaccharide extracting amount was 4. 35 mg/g. Under the optimized extracting conditions,the average extracting amount of S. nudus polysaccharide was 4. 38 mg/g,which is close to the theoretical predicted value( 4. 35 mg/g). And the results of this study also showed that different concentrations of polysaccharide solutions have different scavenging effects on DPPH free radical. At the polysaccharide concentration of0. 16 mg/ml,the maximum value of DPPH radical scavenging rate was 7. 22%,indicating that polysaccharide has certain antioxidant capacity. [Conclusions]This method is a new trial with satisfactory results.
基金Supported by National Natural Science Foundation of Hainan Province(217157)Fund for Construction of Hainan Provincial Key Discipline(Thalassochemistry) in 2017
文摘[Objectives] This study was conducted to optimize the determination conditions of amino acids from abalone. [Methods] The sample was treated by acid hydrolysis method and subjected to 2,4-2 nitro fluorobenzene column derivatization. The amino acid content in abalone was determined by HLPC,and the nutritional value of the amino acids was evaluated with egg protein model put forward by Institute of Nutrition and Food Hygiene,Chinese Academy of Preventive Medicine. [Results] Abalone contains full amino acids. According to the FAO/WHO ideal,it is a high-quality protein source and suitable for supplement of protein source for human body. [Conclusions]The experimental method has simple operation and could achieve a good effect with wide linear range and correlation coefficient over 0. 999 8,and the obtained results are satisfactory.
基金Supported by Basic and Applied Basic Research Plan of Hainan Province in2019 (2019RC245)Natural Science Foundation of Hainan Province in 2017(217157)。
文摘[Objectives] This study was conducted to optimize the extraction process of protocatechuic acid from Emilia sonchifolia DC. [Methods] The optimal extraction conditions were determined by single factor,response surface analysis and variance analysis,and the content of protocatechuic acid was determined by HPLC. [Results] The protocatechuic acid standard curve equation was: y = 1 435 x + 8 403,R^2= 0. 999 8,indicating a good linear relationship. The optimal extraction conditions were as follows: a temperature at 80 ℃,an extraction time of 1 h,a material-to-liquid ratio at 1:10 and an ultrasonic power of 600 W,and the content of protocatechuic acid extracted was 1. 93 mg/g. The method showed a RSD of 0. 41%,less than 2%,and the detection limit was 0. 0000047261 g/ml.The experimental sample X1 was the low-level 0. 1 mg/ml standard solution,which showed recovery of protocatechuic acid between 100.8% and 105.2%,with a RSD of 0. 013%;and the sample X2 was the high-level 1. 0 mg/ml standard solution,which exhibited recovery between 100. 6% and 102. 2%,with a RSD of 0.076%. Thus,the recovery was high,and the requirements of the performance index were met. [Conclusions] The detection method is stable and reliable and can produce satisfactory results.
基金Supported by Hainan Provincial Natural Science Foundation of China,High-level Talent Project(321RC587),Classification of sea snakes in the South Sea China based on molecular Systematics,morphology and climate modelSpecial Scientific Research Trial Production Project of Sanya City(2016KS05),Identification of sea snake species and construction of DNA barcoding based on molecular systematics.
文摘[Objectives]The most common gene fragment used in animal DNA barcode technology is COI,but it is not necessarily suitable for all species.This study was conducted to screen genes suitable for the DNA barcode of sea snakes.[Methods]All COI and cytb gene sequences on GenBank were searched and downloaded.After the comparison with Mega software,clustering trees of MrBayes system were established.[Results]Interspecies distances were greater than intraspecies distances for the two genes.The topological structures of their molecular hierarchical clustering trees were clear,and the support rates were high.[Conclusions]Therefore,it is concluded that not the DNA barcode of each species must be gene COI.Cytb is more suitable in terms of the mitochondrial gene of sea snakes.
文摘[Objectives] The effects of copper-based nutrient foliar fertilizer on photosynthetic characteristics,yield,accumulation and distribution of trace elements in various organs,disease prevention effect and soil enzyme activity were studied,so as to provide a theoretical basis for the application of foliar fertilizers in cotton production. [Methods]Through two years of field experiments,six treatments were set in total,namely spraying water( CK),traditional Bordeaux mixture( BDM),Kocide 2000( KCD),copper-based nutrient foliar fertilizer( CF),iron-copper-based nutrient foliar fertilizer( CFFe),and zinc-boron-copper-based nutrient foliar fertilizer( CFZnB). Randomized block arrangement was adopted. Chlorophyll content in leaves was measured at each growth stage of the cotton. Photosynthetic characteristics of leaves were measured at the peak bolling stage. Plants were sampled at initial boll opening stage. The whole plant was divided into root,stem,leaf and cotton boll parts,in which the total copper,total zinc,total iron contents and accumulations were determined. Soil samples were collected from each plot,followed by the determination of soil enzyme activity. Disease index was investigated at bud,flowering and boll-forming and boll opening stage. [Results]( 1) Spraying CFFe,CFZnB,CF and KCD could significantly improve chlorophyll content of cotton leaves,and the CFFe treatment had the highest increase up to13. 30%,followed by the CFZnB treatment,which was 11. 40% higher than the CK; and photosynthetic rate,stomata conductance and transpiration rate could be improved significantly,and the CFFe treatment showed the highest photosynthetic rate,which increased by 26. 35% compared with the CK,followed by the CFZnB treatment,which increased by 17. 96% compared with CK; and intercellular CO2 concentration was significantly reduced.( 2) Spraying BDM,KCD,CF,CFFe and CFZnB can significantly increase total copper content and accumulation in various cotton organs( except the total copper content in the stem part of the CFZnB treatment; the CFZnB and CFFe treatments can significantly increase total zinc content and accumulation in various cotton organs; and spraying CFFe,CFZnB and CF can significantly increase total iron content and accumulation in various cotton organs( except the total iron content in the stem part of the CF treatment).( 3)Spraying CFFe,CFZnB,CF,KCD and BDM greatly reduced the disease index at flowering and boll-forming and boll opening stages.( 4) The CFZnB and CFFe treatments had the highest soil urease activity,which was 7. 14% higher than that of the CK,but the difference from the CK was not significant; the catalase activity of each treatment was significantly higher than that of the BDM treatment; and the sucrase activity of each treatment was significantly higher than that of the CK.( 5) Spraying CFFe,CFZnB,CF and KCD significantly improved lint yield of cotton,and the CFZnB treatment showed the highest yield increase up to 12. 34%,followed by the CFFe treatment,with an increase in the range of 8. 77%-10. 20%. [Conclusions]Copper-based nutrient foliar fertilizers have dual functions of disease control and prevention and plant nutrition and health care,and not only can significantly increase cotton yield,but also has certain disease prevention effect.It is recommended to use copper-based nutrient foliar fertilizers.
文摘[ Objective ] This study aimed to investigate the impacts of different instruments and methods on detection of water samples and evaluate the detection results and pollution share rate. [ Method] Concentrations of six heavy metals in three surface water samples and three underground water samples were detected by AAS and ICP-AES to analyze the differences in detection results and calculate the pollution share rate of heavy metals. [Result] As a result, the pollution share rate of six heavy metals varied significantly. Calculation results of comprehensive pollution share rate based on the lower pollution index of the same heavy metal in the same water sample detected by two methods were different from the results using either method. Due to different detection limits of instruments, detection results of heavy metals in the same water sample were different, which affected the accuracy of environmental quality assessment. [ Conclusion ] The detected pollution share rate varies with different detection limits. Therefore, instruments and methods with lower detection limit should be used. To be specific, AAS is suitable for detection of Pb and Cd, while ICP is suitable for detection of Cu, Zn, Fe and Mn.
基金Supported by National Natural Science Foundation of Hainan Province(217157)Fund for Construction of Provincial Key Discipline(thalassochemistry)in 2017
文摘[Objectives]This study was conducted to optimize the extraction process of Sipunculus nudus polysaccharide.[Methods]S.nudus polysaccharide was extracted by ultrasonic water extraction,with the marine S.nudus as a raw material from Sanya City,Hainan Province,by single factor variable method,to find the optimal extraction conditions including ultrasonic power,solid-liquid ratio,ultrasonic extraction temperature,ultrasonic extraction time,ultrasonic extraction times and lye concentration.The absorbance of the polysaccharide was determined by an ultraviolet spectrophotometer,and polysaccharide yield were calculated.The antioxidant activity of scavenging hydroxyl and DPPH radicals was measured at different concentrations.[Results]The optimal extraction conditions for S.nudus polysaccharide were as follows:solid-liquid ratio at 1∶11 mg/ml,extraction temperature at 60℃,three times of ultrasonic extraction,ultrasonic power of 960 W,extraction time of 1.5 h,and lye concentration of 5%,under which the polysaccharide yield was 3.21%.The scavenging rates of hydroxyl radical and DPPH radical were 12.58%at the concentration of 0.20 mg/ml.Moreover,the scavenging rates increased significantly with the increase of concentration.[Conclusions]This method is a new trial with satisfactory results.
文摘A rapid and sensitive liquid chromatographyetandem mass spectrometry method was developed and validated for the quantification of cyclobenzaprine in dog plasma.After extracted with organic solvent,post-treatment samples were separated on an Agela C18 column interfaced with a triple quadrupole tandem mass spectrometer in positive electrospray ionization mode.Multiple reaction monitoring was performed using the transitions of m/z 276.2/216.1 and m/z 325.1/109.0 to quantify cyclobenzaprine and escitalopram(internal standard),respectively.The mobile phase consisted of acetonitrile:5 mM ammonium acetate:formic acid(90:10:0.01,v/v/v)at a flow rate of 0.3 ml/min.The total analysis time was 2.4 min.The method was linear over the concentration range of 0.0200e10.0 ng/ml.The intra-and inter-day precision was within 12.8%in terms of relative standard deviation(RSD%)and the accuracy within 5.6%in terms of relative error.This method was successfully applied in a pharmacokinetic study of extended-release cyclobenzaprine in dogs.
基金Supported by Scientific Research Project of Colleges and Universities in Hainan Province(Hnky2017-47)Sanya Special Scientific Research Pilot Project(2016KS05)+2 种基金Provincial Key(Supporting)Discipline for Ordinary Colleges and Universities in Hainan Province:Zoology2018 Special Fund for the Development of Institutions of Higher Learning(phaseⅠ)Provincial Characteristic Discipline:Marine Science。
文摘[Objectives] This study was conducted to further investigate the taxonomic status of Hainan population of Trimeresurus stejnegeri from the morphological point of view.[Methods]The difference coefficients between different populations were compared using the 75% law,and the relationship between scales and latitudes was analyzed.[Results] The scales(abdominal and subcaudal) of 325 Trimeresurus individuals were counted according to China Animal Fauna,including156 T.stejnegeri individuals.Some difference coefficients between the Hainan population and others were greater than 1.28,and there was no correlation between the number of scales and latitude.It conforms to subclassification criteria.[Conclusions]The view about the subspecies status of T.stejnegeri chenbihuii should be supported.
基金Supported by National Natural Science Foundation of Hainan Province(217157)2017 Provincial College Students'Innovation and Entrepreneurship Training Program(201711100005)2018 Provincial Key Discipline(Thalassochemistry)Construction Fund
文摘[Objectives] This study was conducted to optimize experimental conditions for extraction of polysaccharides from Sipunculus nudus.[Methods]With the Sipunculus nudus from Sanya as the experimental material,S.nudus polysaccharide was extracted by ultrasonic microwave assisted method,during which univariate factors including solid-liquid ratio,time,temperature,ultrasonic power,microwave power were investigated,to select optimal extracting conditions,which were also demonstrated and optimized by variance and response surface analysis.The optimized conditions were adopted to carry out a test,in which the absorbance of S.nudus polysaccharide was measured with an ultraviolet and visible spectrophotometer,followed by the calculation of the extracting amount of polysaccharide,and precision test and recovery test were also carried out to verify the experimental method.[Results]The standard solutions were determined at the maximum absorption wavelength of 486 nm,and the regression equation was A = 0.2677 C + 0.001 8,R^2= 0.999 8.Solid-liquid ratio,time,temperature,ultrasonic power and microwave power were investigated by univariate analysis and then optimized by response surface method as follows: solid-liquid ratio at 1:20( g/ml),time of 35 min,temperature at 50 ℃,ultrasonic power at 420 W and microwave power at 300 W,under which the measured extracting amount of S.nudus polysaccharide was1.37 mg/g.The RSD was 0.985% in precision experiment.In the repeatability test,the extracting amounts of polysaccharide were 1.41,1.43 and 1.38 mg/g for three parallel tests,respectively,with a RSD of 1.140%.The recovery test obtained following results: for group a( added with glucose standard) : the recovery of S.nudus polysaccharide was in the range of 100.3%-101.4%,RSD = 0.03%; and for group b( not added with glucose standard) : the recovery of S.nudus polysaccharide was in the range of 99.7%-100.3%,RSD = 0.02%.[Conclusions]The research method is stable and reliable.This study provides data basis and reference for follow-up study on S.nudus.
基金Supported by Fund for Provincial Key DIscipline in Colleges and Universities of Hainan Province:Zoology(2017-02-01,HNZ201702)General Project of National Natural Science Foundation of Hainan Province(20163073),Study on the taxonomic status of Trimeresurus produced in Hainan+4 种基金Special Fund for Scientific Research Trail-produce Project of Sanya City(2016KS05)Scientific Research Project of Colleges and Universities of Hainan Province(Hnky2017-47),Study on the taxonomic status of the subspecies Trimeresurus stejnegeri chenbihuii in Hainan based on morphologyMajor Science and Technology Planning Project of Hainan Province(ZDKJ2016009-2-1)Agricultural Science and Technology Innovation Project of Sanya City(2016NK13)Key Discipline Construction Fund of School of Ocean Science and Technology(Special Fund for Development of Institutions of Higher Learning in 2017(the fourth batch)):Marine Science
文摘According to the contradictions about classification on Trimeresurus between ＂China＇s Fauna＂ and international database, the rationality about Trimeresurus divided to multiple genera based on molecular systematies was discussed. The genetic distance was calculated by sequencing 12S gene of the original Trimeresurus snakes, including 80 individuals of 33 species ; and the molecular phylogenetie tree was established by taking Hypnale hypnale as the outgroup. The results showed that the topological structures of ME tree and ML tree were basically consistent, and all of the species in the molecular trees were divided into 8 branches; and the difference of T. albolabris between Hainan and other locations is not obvious. The viewpoint that original Trimeresurus genera subdivided into 8 genera was more rational, and new authoritative reference books are expected to be published in China.
基金Supported by International Scientific and Technological Cooperation Project of Hainan Province(KJHZ2013-04)Special Fund for Development of Colleges and Universities,Fund for Discipline Construction:Marine Engineering
文摘The contents of five kinds of fatty acids(palmitic acid,stearic acid,oleic acid,linoleic acid and linolenic acid)in 56 collected peanut(Arachis hypogaea Linn.)varieties were determined by gas chromatography.The results showed that in the 56 peanut varieties,oleic acid content was in the range of 36.859%-67.093%;linoleic acid content was in the range of 14.122%-61.025%;palmitic acid content was in the range of 8.583%-20.286%;stearic acid content was in the range of 2.442%-8.971%;and linolenic acid content was in the range of 0.028%-0.093%.Peanut samples No.9304,9355 and 9353 had higher oleic acid/linoleic acid(O/L)ratios,which were 4.751,3.623 and 3.049,respectively,while peanut sample No.9337 exhibited the lowest O/L value of 0.899.
基金This work was supported by the Hainan Province Science and Technology Special Fund(Grant No.ZDYF2025XDNY113)the Central Public-interest Scientific Institution Basal Research Fund(Grant No.1630032022007)+2 种基金the Special Fund for Hainan Excellent Team"Rubber Genetics and Breeding"(Grant No.20210203)the Hunan Provincial Natural Science Foundation Project(Grant No.2025JJ50385)in part by the National Natural Science Foundation of China(Grant No.62276276).
文摘As an important tropical cash crop,rubber trees play a key role in the rubber industry and ecosystem.However,a significant challenge in precision agriculture and refined management of rubber plantation lies in the limitations of traditional point cloud segmentation methods,which struggle to accurately extract structural parameters and capture the spatial layout of individual rubber trees.Therefore,we propose an optimized dual-channel clustering method for the UAV LiDAR-based Rubber Tree Point Cloud Segmentation Network(RsegNet)for improved assessment of rubber tree architecture and traits.Firstly,we designed a cosine feature extraction network,termed CosineU-Net,to address the branch-and-leaf overlap problem by calculating the cosine similarity of the spatial and positional features of each point,leveraging deep learning approaches to improve feature representation.Secondly,we constructed a dual-channel clustering module reducing prediction error in rubber tree point cloud data,integrating multi-class association and background classification to tackle background interference.The cluster identification and separation accuracy in high-dimensional data processing is enhanced through a dy-namic clustering optimization algorithm.In our self-built dataset and across five regions of the FOR-instance forest dataset,RsegNet achieved the best performance compared to five state-of-the-art networks,reaching an F-score of 86.1%.This method calculated structural attributes including height,crown diameter,and volume for rubber trees in three areas under different environments in Danzhou City,Hainan Province,providing robust support for precise monitoring,plantation management,and health assessment.
基金This work was supported by the Hainan Province Science and Technology Special Fund(Grant No.ZDYF2025XDNY113)the Central Public-interest Scientific Institution Basal Research Fund(Grant No.1630032022007)+2 种基金the Special Fund for Hainan Excellent Team“Rubber Genetics and Breeding”(Grant No.20210203)the Hunan Provincial Natural Science Foundation Project(Grant No.2025JJ50385)in part by the National Natural Science Foundation of China(Grant No.62276276).
文摘Rubber products have become an important strategic resource in the global economy.However,individual rubber tree segmentation in plantation environments remains challenging due to canopy background interfer-ence and significant morphological variations among trees.To address these issues,we propose a high-precision segmentation network,TM-WSNet(Spatial Geometry Enhanced Hybrid Feature Extraction Module-Wavelet Grid Feature Fusion Encoder Segmentation Network).First,we introduce SGTramba,a hybrid feature extraction module combining Grouped Transformer and Mamba architectures,designed to reduce confusion between tree crown boundaries and surrounding vegetation or background elements.Second,we propose the WGMS encoder,which enhances structural feature recognition by applying wavelet-based spatial grid downsampling and mul-tiscale feature fusion,effectively handling variations in canopy shape and tree height.Third,a scale optimization algorithm(SCPO)is developed to adaptively search for the optimal learning rate,addressing uneven learning across different resolution scales.We evaluate TM-WSNet on a self-constructed dataset(RubberTree)and two public datasets(ShapeNetPart and ForestSemantic),where it consistently achieves high segmentation accuracy and robustness.In practical field tests,our method accurately predicts key rubber tree parameters—height,crown width,and diameter at breast height with coefficients of determination(R^(2))of 1.00,0.99,and 0.89,respectively.These results demonstrate TM-WSNet's strong potential for supporting precision rubber yield estimation and health monitoring in complex plantation environments.
基金supported by National Natural Science Foundation of China(Grant No.12271183)supported by National Natural Science Foundation of China(Grant Nos.12001474 and 12261091)。
文摘Let p≥7 be a prime.We prove thatβ_(p^(2)/p^(2)-1)survives to E_(∞)in the Adams-Novikov spectral sequence.Additionally,using the Thom mapΦ:■,we can see that h0h3 also survives to E_(∞)in the classical Adams spectral sequence.As an application of these results,we prove thatβ^(p)_(p/p)is divisible byβ_(1).
基金supported by the Ministry of Science and Technology of China (2012CB933403)the National Natural Science Foundation of China (21173057, 51425302)the Chinese Academy of Sciences.
文摘In this paper, the bacterial celluloses(BCs) were pyrolysed in nitrogen and then activated by KOH to form a porous three- dimension-network electrode material for supercapacitor applications. Activated pyrolysed bacterial cellulose(APBC) samples with enlarged specific surface area and enhanced specific capacitances were obtained. In order to optimize electrochemical properties, APBC samples with different alkali-to-carbon ratios of 1, 2 and 3 were tested in two electrodes symmetrical capacitors. The optimized APBC sample holds the highest specific capacitance of 241.8 F/g, and the energy density of which is 5 times higher than that of PBC even at a current density of 5 A/g. This work presents a successful practice of preparing electrode material from environment-friendly biomass, bacterial cellulose.
基金supported by National Natural Science Foundation of China(Grant Nos.11571186,11701411,11801580 and 11871284)。
文摘In this paper,we study the topology of moment-angle manifolds and prove a conjecture of S.Gitler and S.Lopez de Medrano concerned with the behavior of the moment-angle manifold under the surgery’cutting off a vertex’on a simple polytope.Let P be a simple polytope of dimension n with m facets and Pv be a poly tope obtained from P by cutting off one vertex v.Let Z=Z(P)and Zv=Z(Pv)be the corresponding moment-angle manifolds.S.Gitler and S.Lopez de Medrano conjectured that:Zv is diffeomorphic to δ[(Z(-D^n+m)×D^2]##^m-n/j=1(m-n/j)(S^j+2×S^m+n-j-1),and they proved the conjecture in the case m<3 n.In this paper we prove the conjecture in the general case.
基金This research was supported by the National Natural Science Foundation of China(52068019)the Hainan Provincial Natural Science Foundation of China(522RC605,520QN231 and 521RC502).
文摘Existing studies about wind pressure on agricultural greenhouse buildings concentrate on the mean wind pressure while ignoring the systematic research on fluctuating wind pressure characteristics and the influence of roof shape on the wind pressure characteristics,which are closely associated with the wind-induced damage mecha-nism.In this study,two typical agricultural greenhouse buildings on tropical islands are selected as prototypes to conduct pressure measurement experiments in the wind tunnel.Based on the wind pressure time series for the two greenhouses,the mean and fluctuating wind pressure distribution pattern and the localized high-pressure generation mechanism are analyzed.Then,the shape coefficient of the two green-houses is compared in depth to the standards from four countries.Besides,wind pressure non-Gaussian determination criteria for agricultural greenhouse buildings considering the roof shape and wind directions are proposed.Lastly,the differences in wind pressure spectra on the roofs and walls of the two greenhouses are sum-marized.The results indicate the roof shape has a significant influence on the wind pressure characteristics.Compared with the pitched roof,the vaulted roof will increase the suction effect on the windward front zone and the middle area,mitigate the suc-tion impact on the leeward roof,and weaken the wind pressure non-Gaussian charac-teristics.The experimental shape coefficient of the pitched-roof greenhouse is basically consistent with the standard from the U.S.,while that of the vaulted-roof greenhouse has some deviation from the existing standards.The results provide a theoretical basis for the wind-resistant design of agricultural greenhouse buildings on tropical islands.
基金supported by National Natural Science Foundation of China(Grant Nos.11801580 and 11871284)supported by National Natural Science Foundation of China(Grant Nos.11871284 and 11761072).
文摘The connected sum is a fundamental operation in geometric topology and combinatorics.In this paper,we study the connection between connected sums of simplicial spheres and the algebraic topology of their corresponding moment-angle manifolds.The cohomology rings of moment-angle manifolds corresponding to connected sums of simplicial spheres are computed,which leads to a conjecture on the topology of such moment-angle manifolds.
