最新刊期
卷 57 ， 期 1 ， 2018
- 摘要：Haemocoagulase Acutus (Halase), a new hemostatic in halase development, is a highperformance thrombinlike enzyme (TLE) derived from snake venom of Agkistrodon acutus. To study the pharmacokinetics of Halase125Ⅰlabeled radioisotope method and radioassay combined with TCA precipitate were applied in rats. Results showed that AUC values were positively correlated with doses under both used methods, and the correlation coefficients were 0.999 8 and 0.999 0 respectively; drug concentration in liver, spleen and heart reached its peak after 5 minutes of administration while most of other organs reached it in 30 minutes,and then gradually decreased; in each time point, drug concentration in the liver was significantly higher than that in other tissues; Halase was completely excreted and mainly in urine.关键词：Haemocoagulase Acutus;pharmacokinetics;rat
- 344
- |
- 348
- |
- 0
发布时间：2023-12-11 - 摘要：The major histocompatibility complex (MHC) class Ⅱβplay an important role in the immune response of teleost. In this study,full-length MHC Ⅱβ cDNA and genomic sequences were obtained from Nile tilapia (Oreochromis niloticus) by rapid amplification of cDNA ends polymerase chain reaction (RACE-PCR).The full length of cDNA was 1 142 bp and the open reading frame (ORF) was 750 bp encoding 249 amino acid. The genomic structure of MHC Ⅱβ genes was similar with other teleost species including 5 exons and 4 introns. By homology comparison and phylogenetic analysis, MHCⅡβ genes of Nile tilapia had a higher identity and a closer evolutionary relationship with perciform fishes than other fishes. The putative protein had 30.6%~78.6% identity with those of other teleosts and mammals. Ten MHC Ⅱβ alleles were obtained from the fifty positive clones of ORF from 25 individuals. The amino acid sequence analysis showed that polymorphism was mostly focused on exon 2.PCR-SSCP and sequencing results revealed one to six different alleles for two to twelve bands in susceptibile or resistant fishes that after Streptococcus iniae challenge,which suggested there were at least 3 loci.qPCR indicated that high expression of MHC Ⅱβ was detected in gill, heart, spleen, and lower expression in kidney, muscle, brain and the lowest expression in skin, intestine and liver. After Streptococcus iniae challenge, the expression presented the tendency of the down-up-down in head and kidney, which demonstrated MHC Ⅱβ involved in tilapia immune response.关键词：Nile tilapia;MHC Ⅱβtissue expression;polymorphism
- 232
- |
- 380
- |
- 0
发布时间：2023-12-11 - 摘要：Culturable bacteria in the sediment of Huixian wetland were isolated by dilution plate coating method and analyzed with 16S rRNA gene sequences. The results showed that total 65 isolates, subordinate to 4 phylums, 12 genera, 24 species, were obtained. These strains belonged to five genera (Bacillus, Paenibacillus, Fictibacillus, Lysinibacillus and Enterococcus) in Firmicutes, two genera (Streptomyces and Rhodococcus) in Actinobacteria , four genera (Pseudomonas, Stenotrophomonas, Pantoea and Delftia) in Proteobacteria and one genus (Chryseobacterium) in Bacteroidetes. The predominant microflora is Bacillus sp. strains, occupying 53.85% of the all the isolates, which conforms to the fact that Huixian wetlands are becoming eutrophic. Totally four kinds of conditional pathogenic bacteria are detected, accounting 15.38% of the isolate, indicating that the ecological environment has been negatively affected by the human activity. There is another one bacteria strain tolerant to PCNB in 300 mg/L or more, and 30 isolates from 12 Genus have arsenic tolerance. This appearance might have direct relationship with local pesticide and fertilizer abuse.关键词：Huixian wetland;culturable bacteria;diversity;eutrophication;drug resistance
- 210
- |
- 399
- |
- 0
发布时间：2023-12-11 - 摘要：Viola baoshanensis, an identified Cd hyperaccumulator can also tolerate and accumulate a certain amount of Pb. To understand the resistance/enrichment molecular mechanism of Viola baoshansis to Pb, suppression subtractive hybridization (SSH) was performed to screen gene segments induced by Pb, and semi-quantitive RT-PCR along with Northorn blotting was then used to verify the relationship between the screened expressed sequence tags (ESTs) and Pb tolerant/accumulation in V. baoshanensis. Twenty-seven different cDNA fragments were obtained via sequences analysis of cDNA inserts obtained from SSH subtractive cDNA library of V. baoshanensis roots. The results of both RT-PCR and Northern blot analysis showed that two cDNA fragments with high homology with xyloglucan endotransglycosylase (XTH) and GTP binding gene were up-regulated under Pb stress. It could be speculated that, in response to Pb stress, cell wall might have some changes and GTP binding protein might play a role in signal transduction.关键词：hyperaccumualtor;Viola baoshanensis;Pb;SSH
- 217
- |
- 317
- |
- 0
发布时间：2023-12-11 - 摘要：Prunus L. subgenus Cerasus (Mill.) A.Gray is a controversial group in infra-subgeneric and species classification. Based on 30 morphological characters data, clustering analysis on 41 species was performed to infer the infra-subgeneric and species classification. The result shows that 41 species are divided into 11 groups, 6 of them only contain 1 species, and others include 2 or more species7 species with controversies, Prunus conradinae Koehne, Prunus glabra (Pamp.) Koehne, Prunus henryi (C.K.Schneid.) Koehne, Prunus duclouxii Koehne, Prunus yunnanensis Franch, Prunus pseudocerasus Lindl. and Prunus pusilliflora Cardot are clustered into 1 group, indicating their related relationship; It would be appropriate to put them in one section or series. Prunus clarofolia C.K.Schneid., Prunus polytricha Koehne, Prunus tatsienensis Batalin are in a group with a close distance in clustering analysis. The disciform glands in the margin of bracts are the distinguishing characters of Prunus tatsienensis to other 2 species, but the character was not found in the original literature and type specimen. And the densely villous of the Prunus polytricha is indistinguishable to other 2 species. The 3 species are proposed to be combined to 1 species.关键词：Prunus;Cerasus;subgenus Cerasus;numerical taxonomy
- 232
- |
- 320
- |
- 0
发布时间：2023-12-11 - 摘要：A nonlinear size-structured population model with distributed delay in birth process is studied. The time lag in birth process and the internal competition are considered in the model. Sufficient conditions for the existence of steady states are obtained by using the method of semigroups.关键词：size-structured populations;distributed delay;steady states;semigroups
- 208
- |
- 281
- |
- 0
发布时间：2023-12-11 - 摘要：A fractional p-Laplacian equation in RNis studied. By virtue of the Mountain Pass theorem, the existence of weak solutions for the problem is obtained, with the condition imposed on the nonlinearity is weaker than the classical Ambrosetti-Rabinowitz condition. The results extend known conclusions.关键词：fractional p-Laplacian equation;weak solution;Mountain Pass theorem
- 184
- |
- 265
- |
- 0
发布时间：2023-12-11 - 摘要：The fractional integral and differential equation with nonlinear delay is studied with Jacobi spectralcollocation method. After proper linear transformation, an approximate solution and an approximate derivative of the solution are obtained by Gauss quadrature formula. By Jacobi collocation discretization, a rigorous error analysis is provided to show that the error of the approximate solution and the error of the approximate derivative both decay exponentially in the infinity norm and the weighted L2-norm.关键词：Jacobi spectral-collocation method;nonlinear delay;fractional derivative;the fractional integral and differential equation;Gauss quadrature formula;convergence analysis
- 212
- |
- 277
- |
- 0
发布时间：2023-12-11 - 摘要：A new quasi-contractive condition is studied. It is proven that the self-mappings satisfying the new contractive condition has a unique fixed point on non-normal cone metric spaces with Banach algebras. Furthermore, a unique fixed theorem under the more general quasi-contractive condition is given. The obtained result generalizes and improves some well-known fixed point theorems for quasi-contractive mappings.关键词：cone metric space with Banach algebras;fixed point;quasi-contraction;generalized quasi-contraction;c-sequence
- 210
- |
- 281
- |
- 0
发布时间：2023-12-11 - 摘要：The vertex-distinguishing total colorings of the disjoint union mC6of m cycles of length 6 are studied and the vertex-distinguishing total chromatic number of mC6is determined. The result shows that the VDTC conjecture is valid for mC6.关键词：cycle;the disjoint union;vertex-distinguishing total coloring;vertex-distinguishing total chromatic number
- 226
- |
- 282
- |
- 0
发布时间：2023-12-11 - 摘要：Street vendors problem is a challenge to city management in China. Vendors on the street provide convenience for citizens on one hand, and to some extent disturb the daily order of cities on the other hand. Most studies on street vendors focus on the mechanics of vendors aggregation with certain management methodology, and focus on vendors of particular streets. A quantitative modeling on vendor distribution is rare. A number of factors with complex relationship to one another decide the aggregation of street vendors, therefore, the algorithm of random forest is suitable for its application to building classifiers with complex features. With this algorithm not relying on particular critical factor, problems occurred frequently in other algorithms, such as outliers, noises and overfitting, can be well avoided. Further analysis can be made since the algorithm provides magnitude for each street vendors concerned factors. According to literature and field investigation, average house price per square, length of street segments, folks number, bus line number are chosen for modeling. Haizhu district of Guangzhou has been investigated. Taking kappa coefficient and overall accuracy as standard, the optimum predict model of street vendors is generated with training and parameters adjustment, setting no vendor as grade 1, 1~10 vendors as grade 2, 11~20 vendors as grade 3, 21 or more vendors as grade 4. The proposed model of street vendors distribution which predicts the appearance of street vendors, not only facilitates city planning and management, but also throws new light on relevant research.关键词：random forest;street vendor;Guangzhou
- 262
- |
- 313
- |
- 0
发布时间：2023-12-11 - 摘要：Based on the daily precipitation data collected from 50 meteorological stations in South China, the temporal and spatial variations and abnormal distributions of extreme precipitation events defined by the modified percentile method in the early rainy season (ERS) and the late rainy season (LRS) of South China from 1961 to 2014 were analyzed and possible reasons of differences were discussed by using morelet wavelet analysis and SVD method. The results indicate that the extreme precipitation indexes of ERS and LRS during recent 54 years have a significant interannual variation with 3-5 years and 6-8 years periods, respectively, and showing a trend of slight increase. The distributions of extreme precipitation index are also significantly different between ERS and LRS. The maximum anomalies of ERS are mainly in the northeast Guangxi and central part of Guangdong, but those of LRS are near the coastal areas. The possible reasons for the differences between ERS and LRS are as follows: ① The atmospheric circulation and SST anomalies in the preceding winter can be considered as important factors of the extreme precipitation events in ERS of South China. Due to the onset of summer monsoon, the strong southwesterlies carrying warm and wet air from the South China Sea merge with the north cold air at the northcentral region of south China, and convection becomes stronger, which is more prone to heavy precipitation. The increase of SST in tropical Pacific, especially over the central eastern Pacific, creates a favorable condition for extreme precipitation in ERS. ② The extreme precipitation in LRS shows no obvious relationship with atmospheric circulation features. The warmer local SST and stronger convection are helpful for tropical cyclones to move westward, which increases extreme precipitation in the coastal areas of South China.关键词：extreme precipitation;early rainy season and latter rainy season;interannual variations;temporal and spatial characteristics
- 546
- |
- 379
- |
- 0
发布时间：2023-12-11 - 摘要：The chroma and its major controlling factors of the Junwangcun loess-paleosol profile in the Hanzhong basin have been studied. The results show that the lightness is strongly linked to the organic matter. By contrast, the redness is strongly linked to the types and concentrations of iron oxides. The curves of chroma present a similar pattern to the curves of magnetic susceptibility. L*, a*, a*/b* are sensitive to climate response, which can be used as a good alternative climate index to record the changes in climate and pedogenic environment. The change of chroma indicates a cold and dry climate during the late Pleistocene (55.5~11.5 ka BP), a climate shift from cold-dry to warm-humid during the early Holocene (between 11.5~8.5 ka BP), a warm and humid climate during the mid-Holocene (between 8.5~3.0 ka BP), and a cooler and drier climate during the late Holocene (since 3.0 ka BP). The climate is not persistently steady during the late Pleistocene, with a shortterm warm and wet climate in the glacial period (38.8~25.6 ka BP).关键词：chroma;loess-paleosol;climate change;Hanzhong basin
- 222
- |
- 550
- |
- 0
发布时间：2023-12-11 - 摘要：We aimed to clarify the variation characteristics of soil water and the soil water deficit of artificial forestland in order to provide theoretical support for the selection of vegetation types and ecological restoration pattern. It was necessary to measure soil water in Northwestern Shanxi Loess hilly regions in Lan county. The moisture storage capacity and soil water deficit index of Cartagena korshinskii, Pinus tabuliformis and abandoned land in soil profiles of 0~600 cm depth were calculated to quantify soil water deficit during the rainy season and non-rainy season. The results showed that : ① The soil water changed with vegetation types, and even for the same vegetation type, the soil water was not consistent with other soil layers. The soil water content of 3 vegetation types showed first decreasing and then increasing trend with soil depth on the whole. Soil water profile contents of Cartagena korshinskii and Pinus tabuliformis showed a decreasing trend in the depth of 300 cm and 400 cm, respectively. In addition, the soil water content of abandoned land was higher than that of other artificial forestlands, and presented increasing type. ② The effective moisture storage capacity range showed the same trend for 3 vegetation types, with abandoned land＞Cartagena korshinskii＞ Pinus tabuliformis, and the deficit soil water storage presented Pinus tabuliformis＞Cartagena korshinskii＞abandoned land. ③ There was a significant deficit phenomenon of Cartagena korshinskii and Pinus tabuliformis. The plot compared soil water deficit index of Cartagena korshinskii land and Pinus tabuliformis land was 0.24, 0.69, respectively. Nevertheless, the plot compared soil water deficit index of abandoned land was only -0.19. Therefore, the water deficiency of Pinus tabuliformis land was worse than that of other soil types as a whole.关键词：soil water deficit;artificial forestland;vegetation types;northwest Shanxi Province
- 223
- |
- 314
- |
- 0
发布时间：2023-12-11 - 摘要：The internal zone of nephelinesyenite in Liangkou Yajishan, Guangdong Province is composed of amphibolebearing nephelinesyenite, with SiO2averaging 60.45%, K2O/Na2O averaging 0.97, Nb/Ta averaging 22.68, Zr/Hf averaging 39.96，ΣCe/ΣYb averaging 6.32，and δEu(0.30) The external zone, Bi-Am-syenites zone，have average SiO2of 60.34%， average K2O/Na2O of 1.50， average Nb/Ta of 21.23， average Zr/Hf of 43.07，average ΣCe/ΣYb of 7.85，and negative anomaly in Eu（δEu=0.47）. Isotopic studies show that the rock formation time is about 134.6 ± 8.9 Ma (Rb-Sr whole rock isochron method), with average ISrof 0.706 75， average εNd(t) of 2.8. Isotope features suggest that the magmatic rocks were derived from the upper mantle. The intrusive rocks formed at a continent-continent post-collisional extension setting, which was significant to the early Cretaceous tectonic evolution of the South China Block.关键词：nepheline syenites;alkaline rock;A-1-type rock;continental crust extensional tectonic setting;Yajishan at Liangkou
- 375
- |
- 312
- |
- 0
发布时间：2023-12-11 - 摘要：The social impact of global climate change is currently one of the important fields of global change research. Studying the historical climate change and its social impact from historical perspective could provide the valuable references for current human response to the global warming. Based on the previous studies, the climate changes in the world and in China during the North Song dynasty were summed up. The study results pointed out that the climate during the North Song dynasty changed from warm in the early stage to cold and dry in the late stage because of the unique natural environment in China, which just lied between the turning period of the late Tang dynasty and the little ice age of Ming and Qing dynasties. The obvious climate fluctuation and the great change rate of precipitation caused the higher frequency of flood disaster during the North Song dynasty, which has caused the great influence on agriculture production, social and economic development. The study results have very important implications to understanding the past climate change and its impact.关键词：climate change;social impact;the North Song dynasty
- 1553
- |
- 486
- |
- 0
发布时间：2023-12-11 - 摘要：This article comparatively analyzed the four designed flood recurrence levels of bivariate flood joint distribution of flood peak discharges and flood volumes by using Archimedean copulas function, Kendall distribution function and survival Kendall distribution function. The annual maximum flood peak discharges and the corresponding flood volumes of Qilinzui hydrometric station at Zengjiang River as an example, the ‘OR’ primary return periods, ‘AND’ primary return periods, Kendall return periods and survival Kendall return periods of bivariate flood joint distribution and the most likely design flood quantiles were computed by using the optimally fitted Gumbel-Hougaard copula. The main conclusions of this study can be summarized as follows: comparing the different specific flood return periods, the Kendall return periods can be more accurately reflect the flood risks relative to ‘OR’ primary return periods; while the survival Kendall return period can be more accurately reflect the flood risks when two variables for flood were supercritical at the same time with respect to ‘AND’ primary return periods. The univariate flood design value has reached safety standards according to the relevant specifications of the current design requirements. The estimated flood design quantiles of the ‘OR’ primary return periods and two variables with the same frequency were obviously higher than the single variable floods. The mostlikely design realizations of the Kendall return periods and the survival Kendall return periods can serve as a new selection for flood control projects safety and risk management.
- 329
- |
- 292
- |
- 0
发布时间：2023-12-11 - 摘要：In the structural design and safety assessment of nuclear power plant, it is of great significant to analyze the seismic response of containment. Based on the three-dimensional finite element model of the containment, the nonlinear seismic response analysis is carried out at the ultimate safety ground motion, especially the seismic response spectrum of some floors are calculated by the time history method. In addition, the effect of different target damping ratios on the floor response spectrum were analyzed and compared. It is indicated that the detailed 3D finite element model is capable to reflect the actual response of structures and ensure the integrity at the ultimate safety ground motion. The structural response spectrum of structure obtained from the analysis could be used as the input data of the substructure seismic analysis.关键词：nuclear containment;3D finite element model;ultimate safety ground motion;floor response spectra
- 236
- |
- 305
- |
- 0
发布时间：2023-12-11 - 摘要：Diesel particulate filter (DPF) is one of the most effective techniques for the purification of diesel particulate matter (PM). With micro wood fiber as DPF filter material, it has the advantages of high filtration efficiency, low exhaust back pressure and large dust content, but it can not continuous operate under high temperature of 300~400 ℃ and must work with cooling device. In this paper, based on the air cooling design calculation model, the influence of inner diameter, pipe distance, fin height and fin distance on the cooling performance is analyzed to design the tube fin type cooler, which is appropriate to the Lister Petter AA1 diesel engine. Furthermore, the efficiency of the cooling design has been proved by the cooling performance test set up in this research. The results show that the fin tube cooler has good cooling efficiency that the temperature of the exhaust gas can be decreased 220 ℃ and lower),while the cooler pressure drop is always below 14 kPa.关键词：micron wood fiber;diesel;diesel particulate filter;cooler
- 175
- |
- 320
- |
- 0
发布时间：2023-12-11 - 摘要：In this work, the computational fluid dynamics(CFD) method is used to study the resistance character of an underwater vehicle in a specific undersea tunnel circumstance. In order to prove the validity of the proposed method, the standard Suboff model was numerically calculated and the simulation results were in agreement with the experimental data published by ITTC. This work presents different effects of resistance and pressure on two front supporting structures with the simulation results of the two different models. The flow field around the vehicle and the resistance characteristics changing under different working conditions were analyzed. The results show that the bar supporting structure can reduce the resistance and surface pressure fluctuation compared with the board model and the trend of resistance and pressure changes under different working conditions is different. In the downstream direction, the resistance decreases with the increase of navigation speed, where in the upstream direction it goes by contraries.关键词：underwater vehicle;resistance characters;supporting structure;undersea tunnel;numerical simulation
- 352
- |
- 387
- |
- 0
发布时间：2023-12-11
- Postal code：510275
- Tel：020-84112585，84113223 Email：xuebaozr@mail.sysu.edu.cn
- Technical support is provided by Beijing Founder electronics co., LTD 京ICP备09064830号-19
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0