The aromatic compounds,including o-xylene,m-xylene,p-xylene,and ethylbenzene,primarily originate from the catalytic reforming of crude oil,and have a wide variety of applications.However,because of similar physical an...The aromatic compounds,including o-xylene,m-xylene,p-xylene,and ethylbenzene,primarily originate from the catalytic reforming of crude oil,and have a wide variety of applications.However,because of similar physical and chemical properties,these compounds are difficult to be identified by gas chromatography(GC)without standard samples.With the development of modern nuclear magnetic resonance(NMR)techniques,NMR has emerged as a powerful and efficient tool for the rapid analysis of complex and crude mixtures without purification.In this study,the parameters of one-dimensional(1D)total correlation spectroscopy(TOCSY)NMR techniques,including 1D selective gradient TOCSY and 1D chemicalshift-selective filtration(CSSF)with TOCSY,were optimized to obtain comprehensive molecular structure information.The results indicate that the overlapped signals in NMR spectra of nonpolar aromatic compounds(including o-xylene,m-xylene,p-xylene and ethylbenzene),polar aromatic compounds(benzyl alcohol,benzaldehyde,benzoic acid),and aromatic compounds with additional conjugated bonds(styrene)can be resolved in 1D TOCSY.More importantly,full molecular structures can be clearly distinguished by setting appropriate mixing time in 1D TOCSY.This approach simplifies the NMR spectra,provides structural information of entire molecules,and can be applied for the analysis of other structural isomers.展开更多
“Long-Dan”is an important traditional Chinese medicinal(TCM)herb used widely for the treatment of inflammation,hepatitis,rheumatism,cholecystitis,and tuberculosis.In the Chinese Pharmacopoeia,the roots and rhizomes ...“Long-Dan”is an important traditional Chinese medicinal(TCM)herb used widely for the treatment of inflammation,hepatitis,rheumatism,cholecystitis,and tuberculosis.In the Chinese Pharmacopoeia,the roots and rhizomes of four species from the genus Gentiana(Gentianaceae)are recorded as the original materials of“Long-Dan”,called Gentianae Radix et Rhizoma.The species included G.manshurica,G.scabra,G.triflora and G.rigescens,which are distributed in different areas of China.Though iridoid and secoiridoid glucosides were reported as the main constituents in“Long-Dan”,these four different species also resulted in different minor components,which may related to their pharmacological activities.Herein,we summarized the herbal textual study,distribution,chemical constituents,biological investigation and quality control of the recorded“Long-Dan”origins in Chinese Pharmacopoeia during the period 1960 to 2011.展开更多
The importance of soil organic carbon(SOC) under forests in the global carbon cycle depends on the stability of the soil carbon and its availability to soil microbial biomass.We investigated the effects of successive ...The importance of soil organic carbon(SOC) under forests in the global carbon cycle depends on the stability of the soil carbon and its availability to soil microbial biomass.We investigated the effects of successive rotations of Chinese fir(Cunninghamia lanceolata(Lamb.) Hook) plantations on the stability of SOC and its availability to microbes by adopting the two-step hydrolysis with H2SO4 and density fractionation.The results showed that successive rotations of Chinese fir decreased the quantity of total SOC,recalcitrant fraction,and carbohydrates in Labile Pool I(LP Ⅰ),and microbial properties evidently,especially at 0-10 cm horizon.However,cellulose included in Labile Pool II(LP Ⅱ) and the cellulose/total carbohydrates ratio increased in successive rotations of Chinese fir.The non-cellulose of carbohydrates included in LP I maybe highly available to soil microbial biomass.Hence the availability of SOC to microbial biomass declined over the successive rotations.Although there was no significant change in recalcitrance of SOC over the successive rotations of Chinese fir,the percentage of heavy fraction to total SOC increased,suggesting that the degree of physical protection for SOC increased and SOC became more stable over the successive rotations.The degradation of SOC quality in successive rotation soils may be attributed to worse environmental conditions resulted from disturbance that related to "slash and burn" site preparation.Being highly correlated with soil microbial properties,the cellulose/total carbohydrates ratio as an effective indicator of changes in availability of SOC to microbial biomass brought by management practices in forest soils.展开更多
Chinese shrimp(Fenneropenaeus chinensis)is an economically important aquaculture species in China.However,cytogenetic and genomic data is limited in the organism partly because the chromosomes are difficult to isolate...Chinese shrimp(Fenneropenaeus chinensis)is an economically important aquaculture species in China.However,cytogenetic and genomic data is limited in the organism partly because the chromosomes are difficult to isolate and analyze.In this study,fluorescence in-situ hybridization(FISH) was used to identify the chromosomes of F.chinensis.The 5S ribosomal RNA gene(rDNA)of F. chinensis was isolated,cloned and then used as a hybridization probe.The results show that the 5S rDNA was located on one pair of homologous chromosomes in F.chinensis.In addition,triploid shrimp were used to evaluate the feasibility of chromosome identification using FISH and to validate the method.It was confirmed that 5S rDNA can be used as a chromosome-specific probe for chromosome identification in F.chinensis.The successful application of FISH in F.chinensis shows that chromosome-specific probes can be developed and this finding will facilitate further research on the chromosomes of penaeid shrimps.展开更多
The ambiguity function of Chinese standard Digital Television Terrestrial Broadcasting (DTTB) signals for passive radar contains one main peak and many side peaks. The side peaks may cause the false alarms. The relati...The ambiguity function of Chinese standard Digital Television Terrestrial Broadcasting (DTTB) signals for passive radar contains one main peak and many side peaks. The side peaks may cause the false alarms. The relative positions and the reasons for the side peaks are analyzed and a new algorithm for side peaks suppression is proposed in this paper. The algorithm, in consideration of the characteristics of the structure of the frame, can eliminate the side peaks completely in the valid Doppler observation interval by setting the reference signals to zero at equal intervals. Both the simulative and experimental results show that this algorithm can improve the performance of target detection of the passive radar based on DTTB signal.展开更多
Background: Soybean isoflavones are structurally similar to mammalian estrogens and therefore may act as estrogen agonists or antagonists. However, it has not been determined if they have any negative effects on repro...Background: Soybean isoflavones are structurally similar to mammalian estrogens and therefore may act as estrogen agonists or antagonists. However, it has not been determined if they have any negative effects on reproductive parameters in male livestock. Therefore, the objective of this study was to evaluate the effects of soybean isoflavones on male reproduction using Chinese mini-pig boars as a model. Fifty Xiang boars were randomly divided into five groups and fed diets containing 0, 125, 250, or 500 ppm soybean isoflavones or 0.5 ppm diethylstilbestrol for 60 days. Results: Dietary supplementation with 250 ppm of soy isoflavones markedly increased the testis index (P<0.05), fructose content (P <0.05), and α-glycosidase content in testicular tissue (P<0.01), as well as increased the number of viable germ cells (P<0.01) and the level of Bcl-2 protein (P <0.01). However, 500 ppm of soybean isoflavones significantly reduced both testis and epididymis indexes (P<0.05) and lactate dehydrogenase levels (P<0.01), as well as reduced serum LH and testosterone levels (P<0.05). High levels of soybean isoflavones also increased malondialdehyde levels (P<0.05), as well as increased the numbers of early and late apoptotic germ cells (P<0.01) and the level of Bax proteins (P<0.05) in the testis. Conclusions: The results of this study indicate that consumption of soy isoflavones at dietary levels up to 250 ppm did not adversely affect reproductive parameters in Chinese mini-pig boars whereas higher levels of soy isoflavones may adversely affect male reproduction.展开更多
Peptides in shrimp hemolymph play an important role in the innate immune response.Analysis of hemolymph will help to detect and identify potential novel biomarkers of microbial infection.We used magnetic bead-based pu...Peptides in shrimp hemolymph play an important role in the innate immune response.Analysis of hemolymph will help to detect and identify potential novel biomarkers of microbial infection.We used magnetic bead-based purification(ClinProt system) and matrix-assisted laser desorption/ionization time of flight mass spectrometry(MALDI-TOF MS) to characterize shrimp hemolymph peptides.Shrimp serum and plasma were used as the source of samples for comparative analysis,and it was found that serum was more suitable for shrimp hemolymph peptidomic analysis.To screen potential specific biomarkers in serum of immune-challenged shrimps,we applied magnetic bead-based MALDI-TOF MS to serum samples from 10 immune-challenged and 10 healthy shrimps.The spectra were analyzed using FlexAnalysis 3.0 and ClinProTools 2.1 software.Thirteen peptide peaks significantly different between the two groups were selected as candidate biomarkers of lipopolysaccharide(LPS)-infection.The diagnostic model established by genetic algorithm using five of these peaks was able to discriminate LPS-challenged shrimps from healthy control shrimps with a sensitivity of 90% and a specificity of 100%.Our approach in MALDITOF MS-based peptidomics is a powerful tool for screening bioactive peptides or biomarkers derived from hemolymph,and will help to enable a better understanding of the innate immune response of shrimps.展开更多
We collected five specimens of threadfin bream from Beihai, Guangxi, China in March 2010. These were subsequently identified as red filament threadfin bream Nemipterus marginatus (Valenciennes, 1830), being the first ...We collected five specimens of threadfin bream from Beihai, Guangxi, China in March 2010. These were subsequently identified as red filament threadfin bream Nemipterus marginatus (Valenciennes, 1830), being the first record of this species from Chinese waters. N. marginatus is distinguished by the following characteristics: lower border of eye lies above a line from tip of snout to upper base of pectoral fin; mouth oblique, maxillary extending to lower anterior border of pupil; teeth in jaws in several rows, pointed; upper jaw with 3 to 5 pairs of small recurved canines; suborbital with straight lower edge and rounded posterior edge; pectoral fins extending to between level of anus and origin of anal fin; pelvic fins reaching to the first or second anal rays; caudal fin forked, upper lobe tails into a short reddish filament; dorsal fin bluish with a yellow margin distally and a broad yellow median band which subdivides posteriorly into 3 small bands.展开更多
Data assimilation is a powerful tool to improve ocean forecasting by reducing uncertainties in forecast initial conditions.Recently,an ocean data assimilation system based on the ensemble optimal interpolation(EnOI) s...Data assimilation is a powerful tool to improve ocean forecasting by reducing uncertainties in forecast initial conditions.Recently,an ocean data assimilation system based on the ensemble optimal interpolation(EnOI) scheme and HYbrid Coordinate Ocean Model(HYCOM) for marginal seas around China was developed.This system can assimilate both satellite observations of sea surface temperature(SST) and along-track sea level anomaly(SLA) data.The purpose of this study was to evaluate the performance of the system.Two experiments were performed,which spanned a 3-year period from January 1,2004 to December 30,2006,with and without data assimilation.The data assimilation results were promising,with a positive impact on the modeled fields.The SST and SLA were clearly improved in terms of bias and root mean square error over the whole domain.In addition,the assimilations provided improvements in some regions to the surface field where mesoscale processes are not well simulated by the model.Comparisons with surface drifter trajectories showed that assimilated SST and SLA also better represent surface currents,with drifter trajectories fitting better to the contours of SLA field than that without assimilation.The forecasting capacity of this assimilation system was also evaluated through a case study of a birth-and-death process of an anticyclone eddy in the Northern South China Sea(NSCS),in which the anticyclone eddy was successfully hindcasted by the assimilation system.This study suggests the data assimilation system gives reasonable descriptions of the near-surface ocean state and can be applied to forecast mesoscale ocean processes in the marginal seas around China.展开更多
The teleseismic receiver functions of 48 stations belonging to the CCDSN are used to invert the crustal structure beneath each station with the neighborhood algorithm.Thin layers with low velocity have been found bene...The teleseismic receiver functions of 48 stations belonging to the CCDSN are used to invert the crustal structure beneath each station with the neighborhood algorithm.Thin layers with low velocity have been found beneath eight stations with"abnormal"observed receiver functions.Unreasonable results of few stations have been adjusted lightly with the trial-and-error method.The final result indicates that the crust in the western China is relatively thicker than the eastern China.The crust thickness beneath the Tibetan plateau is very large,which reaches 84 km at the station LSA.Double-crust structure exists below the stations LSA and CAD in Tibet,which might imply the collision between the Indian and Eurasian plates.A pronounced low velocity zone in the lower crust beneath the station TNC of Yunnan province might relate to the high temperature or emergence of partially molten material caused by Quaternary volcano,magma and geothermal activities in this area.The Moho is a transitional zone made up of thin layers instead of simple sharp discontinuity beneath several stations.The Conrad discontinuity is clearly identified beneath 20 stations mainly in the southeastern China,whereas it is blurry beneath 14 stations and uncertain beneath remaining stations.展开更多
A systematic survey of As, Cd, Cr, Cu, Ni, Pb and Zn concentrations in vegetables from 416 samples (involving 100 varieties) in Beijing was carried out for assessing the potential health risk to local inhabitants. The...A systematic survey of As, Cd, Cr, Cu, Ni, Pb and Zn concentrations in vegetables from 416 samples (involving 100 varieties) in Beijing was carried out for assessing the potential health risk to local inhabitants. The results indicated that the metal concentrations in vegetables ranged from < 0.001 to 0.479 μg/g fresh weight (fw) (As), < 0.001 to 0.101 μg/g fw (Cd), < 0.001 to 1.04 μg/g fw (Cr), 0.024 to 8.25 μg/g fw (Cu), 0.001 to 1.689 μg/g fw (Ni), < 0.001 to 0.655 μg/g fw (Pb) and 0.01 to 25.6 μg/g fw (Zn), with average concentrations of 0.013, 0.010, 0.023, 0.51, 0.053, 0.046 and 2.55 μg/g fw, respectively. The results showed that the concentrations of As, Cr, Cu, Cd, Pb and Ni in vegetables from open-fields were all significantly higher than those grown in greenhouses. In addition, in local-produced vegetables, all HMs except Zn were significantly higher than those in provincial vegetables. The estimated daily intake (EDI) of As, Cd, Cr, Cu, Ni, Pb and Zn from vegetables was 0.080, 0.062, 0.142, 3.14, 0.327, 0.283 and 15.7 μg/(kg body weight (bw)·d) for adults, respectively. Arsenic was the major risk contributor for inhabitants since the target hazard quotient based on the weighted average concentration (THQw) of arsenic amounted to 44.3% of the total THQ (TTHQ) value according to average vegetable consumption. The TTHQ was lower than 1 for all age groups, indicating that it was still safe for the general population of Beijing to consume vegetables.展开更多
Based on the acquaintance of the regional background of urban-rural transformational development and investigations on the spot,this paper discusses the holistic situation, dominant factors and mechanism of arable lan...Based on the acquaintance of the regional background of urban-rural transformational development and investigations on the spot,this paper discusses the holistic situation, dominant factors and mechanism of arable land loss and land for construction occupation in the coastal area of China over the last decade,with the aid of GIS technology.Conclusions of the research are summarized as follows:(1)the arable land had been continuously decreasing from 1996 to 2005,with a loss of 1,708,700 hm 2 and an average decrement of 170,900 hm 2 per year;(2)land for construction increased 1,373,700 hm 2 ,with an average increment of 153,200 hm 2 per year;(3)total area of encroachment on arable land for construction between 1996 and 2005 was 1,053,100 hm 2 ,accounting for 34.03%of the arable land loss in the same period,the percentages of which used for industrial land(INL),transportation land(TRL),rural construction land(RUL)and town construction land(TOL)are 45.03%,15.8%,15.47%and 11.5%,respectively;and(4)the fluctuation of the increase of construction land and encroachment on arable land in the area were deeply influenced by the nation's macroscopic land-use policies and development level of regional economy.The growth of population and advancement of technology promoted the rapid industrialization, construction of transportation infrastructures,rural urbanization and expansion of rural settlements in the eastern coastal area,and therefore were the primary driving forces of land-use conversion.展开更多
A long-term experiment was conducted to investigate how long-term fertilization and rice straw incorporation into soil affect soil glomalin, C and N. The combined application of chemical fertilizer and straw resulted ...A long-term experiment was conducted to investigate how long-term fertilization and rice straw incorporation into soil affect soil glomalin, C and N. The combined application of chemical fertilizer and straw resulted in a significant increase in both soil easily extractable glomalin (EEG) and total glomalin (TG) concentrations, as compared with application of only chemical fertilizer or no fertilizer application. The EEG and TG concentrations of the NPKS (nitrogen, phosphorus, and potassium fertilizer application + rice straw return) plot were 4.68% and 5.67% higher than those of the CK (unfertilized control) plot, and 9.87% and 6.23% higher than those of the NPK (nitrogen, phosphorus, and potassium fertilizer applied annually) plot, respectively. Application of only chemical fertilizer did not cause a statistically significant change of soil glomalin compared with no fertilizer application. The changes of soil organic C (SOC) and total N (TN) contents demonstrated a similar trend to soil glomalin in these plots. The SOC and TN contents of NPKS plot were 15.01% and 9.18% higher than those of the CK plot, and 8.85% and 14.76% higher than those of the NPK plot, respectively. Rice straw return also enhanced the contents of microbial biomass C (MBC) and microbial biomass N (MBN) in the NPKS plot by 7.76% for MBC and 31.42% for MBN compared with the CK plot, and 12.66% for MBC and 15.07% for MBN compared with the NPK plots, respectively. Application of only chemical fertilizer, however, increased MBN concentration, but decreased MBC concentration in soil.展开更多
Homogenization of climate observations remains a challenge to climate change researchers, especially in cases where metadata (e.g., probable dates of break points) are not always available. To examine the inffuence of...Homogenization of climate observations remains a challenge to climate change researchers, especially in cases where metadata (e.g., probable dates of break points) are not always available. To examine the inffuence of metadata on homogenizing climate data, the authors applied the recently developed Multiple Analysis of Series for Homogenization (MASH) method to the Beijing (BJ) daily temperature series for 1960- 2006 in three cases with different references: (1) 13M-considering metadata at BJ and 12 nearby stations; (2) 13NOM-considering the same 13 stations without metadata; and (3) 21NOM-considering 20 further stations and BJ without metadata. The estimated mean annual, seasonal, and monthly inhomogeneities are similar between the 13M and 13NOM cases, while those in the 21NOM case are slightly different. The detected biases in the BJ series corresponding to the documented relocation dates are as low as -0.71~0C, -0.79~0C, and -0.5~0C for the annual mean in the 3 cases, respectively. Other biases, including those undocumented in metadata, are minor. The results suggest that any major inhomogeneity could be detected via MASH, albeit with minor differences in estimating inhomogeneities based on the different references. The adjusted annual series showed a warming trend of 0.337, 0.316, and 0.365~0C (10 yr)^(-1) for the three cases, respectively, smaller than the estimate of 0.453~0C (10 yr)^(-1) in the original series, mainly due to the relocation-induced biases. The impact of the MASH-type homogenization on estimates of climate extremes in the daily temperature series is also discussed.展开更多
The adsorption and desorption of Cu(Ⅱ) and Pb(Ⅱ) on upland red soil,and paddy soils which were originated from the upland soil and cultivated for 8,15,35 and 85 years,were investigated using the batch method.The stu...The adsorption and desorption of Cu(Ⅱ) and Pb(Ⅱ) on upland red soil,and paddy soils which were originated from the upland soil and cultivated for 8,15,35 and 85 years,were investigated using the batch method.The study showed that the organic matter content and cation exchange capacity (CEC) of the soils are important factors controlling the adsorption and desorption of Cu(Ⅱ) and Pb(Ⅱ).The 15-Year paddy soil had the highest adsorption capacity for Pb(Ⅱ),followed by the 35-Year paddy soil.Both the 35-Year paddy soil and 15-Year paddy soil adsorbed more Cu(Ⅱ) than the upland soil and other paddy soils.The 15-Year paddy soils exhibited the highest desorption percentage for both Cu(Ⅱ) and Pb(Ⅱ).These results are consistent with the trend for the CEC of the soils tested.The high soil CEC contributes not only to the adsorption of Cu(Ⅱ) and Pb(Ⅱ) but also to the electrostatic adsorption of the two heavy metals by the soils.Lower desorption percentages for Cu(Ⅱ) (36.7% to 42.2%) and Pb(Ⅱ) (50.4% to 57.9%) were observed for the 85-Year paddy soil.The highest content of organic matter in the soil was responsible for the low desorption percentages for the two metals because the formation of the complexes between the organic matter and the metals could increase the stability of the heavy metals in the soils.展开更多
Using the latest daily observational rainfall datasets for the period 1961–2008, the present study investigates the interannual variability of June–September (JJAS) mean rainfall in northern China. The regional char...Using the latest daily observational rainfall datasets for the period 1961–2008, the present study investigates the interannual variability of June–September (JJAS) mean rainfall in northern China. The regional characteristics of JJAS mean rainfall are revealed by a rotated empirical orthogonal function (REOF) analysis. The analysis identifies three regions of large interannual variability of JJAS rainfall: North China (NC), Northeast China (NEC), and the Taklimakan Desert in Northwest China (TDNWC). Summer rainfall over NC is shown to have displayed a remarkable dry period from the late 1990s; while over NEC, decadal-scale variation with a significant decreasing trend in the last two decades is found, and over TDNWC, evidence of large interannual variability is revealed. Results also show that the interannual variability of JJAS rainfall in northern China is closely associated with the Northern Hemisphere circumglobal teleconnection (CGT). Correlation coefficients between the CGT index and regional-averaged JJAS mean rainfall over NC and NEC were calculated, revealing values of up to 0.50 and 0.53, respectively, both of which exceeded the 99% confidence level.展开更多
The agricultural land resources of China are relatively limited because of its large population.Therefore,balancing the land use for industrialization,urbanization,and food security is a big challenge.In recent years,...The agricultural land resources of China are relatively limited because of its large population.Therefore,balancing the land use for industrialization,urbanization,and food security is a big challenge.In recent years,rural hollowing in China has resulted in numerous of abandoned rural houses,and the areas with abandoned houses need to be restored into agricultural land with effective land consolidation techniques.This study used the method of benefit-cost analysis and the data collected through field surveys conducted in Yucheng City in the northwest of Shandong Province in March 2009,to examine how hollow villages (HVs) to be created and how to solve the problem.The qualitative and quantitative analyses indicate following results.1) The situation of HVs is becoming increasingly severe under rapid industrialization and urbanization in Yucheng City.2) Poor infrastructure in rural areas and incomplete urbanization are the main factors that have led to the rural hollowing in many major rural regions of China.3) In order to resolve the problem caused by HVs and increase agricultural land,reconstructing rural communities in the countryside is necessary.4) A new mechanism in the provision of compensation funds by developed regions to the villages in less-developed regions must be established.展开更多
基金We thank the Natural Science Foundation of Shanxi Province(202103021224439)National Natural Science Foundation of China(22075308)for financial support.
文摘The aromatic compounds,including o-xylene,m-xylene,p-xylene,and ethylbenzene,primarily originate from the catalytic reforming of crude oil,and have a wide variety of applications.However,because of similar physical and chemical properties,these compounds are difficult to be identified by gas chromatography(GC)without standard samples.With the development of modern nuclear magnetic resonance(NMR)techniques,NMR has emerged as a powerful and efficient tool for the rapid analysis of complex and crude mixtures without purification.In this study,the parameters of one-dimensional(1D)total correlation spectroscopy(TOCSY)NMR techniques,including 1D selective gradient TOCSY and 1D chemicalshift-selective filtration(CSSF)with TOCSY,were optimized to obtain comprehensive molecular structure information.The results indicate that the overlapped signals in NMR spectra of nonpolar aromatic compounds(including o-xylene,m-xylene,p-xylene and ethylbenzene),polar aromatic compounds(benzyl alcohol,benzaldehyde,benzoic acid),and aromatic compounds with additional conjugated bonds(styrene)can be resolved in 1D TOCSY.More importantly,full molecular structures can be clearly distinguished by setting appropriate mixing time in 1D TOCSY.This approach simplifies the NMR spectra,provides structural information of entire molecules,and can be applied for the analysis of other structural isomers.
基金supported by Science and Technology Planning Project of Yunnan Province(2010CD106)the 973 Program of Ministry of Science and Technology of China(2011CB915503)+1 种基金the State Key Laboratory of Phytochemistry and Plant Resources in West China,Chinese Academy of Sciences(P2010-ZZ03)The Fourteenth Candidates of the Young Academic Leaders of Yunnan Province(Min XU,2011CI044).
文摘“Long-Dan”is an important traditional Chinese medicinal(TCM)herb used widely for the treatment of inflammation,hepatitis,rheumatism,cholecystitis,and tuberculosis.In the Chinese Pharmacopoeia,the roots and rhizomes of four species from the genus Gentiana(Gentianaceae)are recorded as the original materials of“Long-Dan”,called Gentianae Radix et Rhizoma.The species included G.manshurica,G.scabra,G.triflora and G.rigescens,which are distributed in different areas of China.Though iridoid and secoiridoid glucosides were reported as the main constituents in“Long-Dan”,these four different species also resulted in different minor components,which may related to their pharmacological activities.Herein,we summarized the herbal textual study,distribution,chemical constituents,biological investigation and quality control of the recorded“Long-Dan”origins in Chinese Pharmacopoeia during the period 1960 to 2011.
基金supported by the National Natural Sci-ence Foundation of China (No. 30470303)the Key Project of the Knowledge Innovation Program of the Chinese Academy of Sciences (No. KZCX2-YW-405)
文摘The importance of soil organic carbon(SOC) under forests in the global carbon cycle depends on the stability of the soil carbon and its availability to soil microbial biomass.We investigated the effects of successive rotations of Chinese fir(Cunninghamia lanceolata(Lamb.) Hook) plantations on the stability of SOC and its availability to microbes by adopting the two-step hydrolysis with H2SO4 and density fractionation.The results showed that successive rotations of Chinese fir decreased the quantity of total SOC,recalcitrant fraction,and carbohydrates in Labile Pool I(LP Ⅰ),and microbial properties evidently,especially at 0-10 cm horizon.However,cellulose included in Labile Pool II(LP Ⅱ) and the cellulose/total carbohydrates ratio increased in successive rotations of Chinese fir.The non-cellulose of carbohydrates included in LP I maybe highly available to soil microbial biomass.Hence the availability of SOC to microbial biomass declined over the successive rotations.Although there was no significant change in recalcitrance of SOC over the successive rotations of Chinese fir,the percentage of heavy fraction to total SOC increased,suggesting that the degree of physical protection for SOC increased and SOC became more stable over the successive rotations.The degradation of SOC quality in successive rotation soils may be attributed to worse environmental conditions resulted from disturbance that related to "slash and burn" site preparation.Being highly correlated with soil microbial properties,the cellulose/total carbohydrates ratio as an effective indicator of changes in availability of SOC to microbial biomass brought by management practices in forest soils.
基金Supported by the Key Program of the National Natural ScienceFoundation of China(No.30730071)the National High-Tech Researchand Development Program of China(863 program)(No.2007AA09Z430)the General Program of National Natural Science Foundation of China(Nos.30471347&40706048)
文摘Chinese shrimp(Fenneropenaeus chinensis)is an economically important aquaculture species in China.However,cytogenetic and genomic data is limited in the organism partly because the chromosomes are difficult to isolate and analyze.In this study,fluorescence in-situ hybridization(FISH) was used to identify the chromosomes of F.chinensis.The 5S ribosomal RNA gene(rDNA)of F. chinensis was isolated,cloned and then used as a hybridization probe.The results show that the 5S rDNA was located on one pair of homologous chromosomes in F.chinensis.In addition,triploid shrimp were used to evaluate the feasibility of chromosome identification using FISH and to validate the method.It was confirmed that 5S rDNA can be used as a chromosome-specific probe for chromosome identification in F.chinensis.The successful application of FISH in F.chinensis shows that chromosome-specific probes can be developed and this finding will facilitate further research on the chromosomes of penaeid shrimps.
文摘The ambiguity function of Chinese standard Digital Television Terrestrial Broadcasting (DTTB) signals for passive radar contains one main peak and many side peaks. The side peaks may cause the false alarms. The relative positions and the reasons for the side peaks are analyzed and a new algorithm for side peaks suppression is proposed in this paper. The algorithm, in consideration of the characteristics of the structure of the frame, can eliminate the side peaks completely in the valid Doppler observation interval by setting the reference signals to zero at equal intervals. Both the simulative and experimental results show that this algorithm can improve the performance of target detection of the passive radar based on DTTB signal.
文摘Background: Soybean isoflavones are structurally similar to mammalian estrogens and therefore may act as estrogen agonists or antagonists. However, it has not been determined if they have any negative effects on reproductive parameters in male livestock. Therefore, the objective of this study was to evaluate the effects of soybean isoflavones on male reproduction using Chinese mini-pig boars as a model. Fifty Xiang boars were randomly divided into five groups and fed diets containing 0, 125, 250, or 500 ppm soybean isoflavones or 0.5 ppm diethylstilbestrol for 60 days. Results: Dietary supplementation with 250 ppm of soy isoflavones markedly increased the testis index (P<0.05), fructose content (P <0.05), and α-glycosidase content in testicular tissue (P<0.01), as well as increased the number of viable germ cells (P<0.01) and the level of Bcl-2 protein (P <0.01). However, 500 ppm of soybean isoflavones significantly reduced both testis and epididymis indexes (P<0.05) and lactate dehydrogenase levels (P<0.01), as well as reduced serum LH and testosterone levels (P<0.05). High levels of soybean isoflavones also increased malondialdehyde levels (P<0.05), as well as increased the numbers of early and late apoptotic germ cells (P<0.01) and the level of Bax proteins (P<0.05) in the testis. Conclusions: The results of this study indicate that consumption of soy isoflavones at dietary levels up to 250 ppm did not adversely affect reproductive parameters in Chinese mini-pig boars whereas higher levels of soy isoflavones may adversely affect male reproduction.
基金Supported by the National Natural Science Foundation of China(No.30600458)
文摘Peptides in shrimp hemolymph play an important role in the innate immune response.Analysis of hemolymph will help to detect and identify potential novel biomarkers of microbial infection.We used magnetic bead-based purification(ClinProt system) and matrix-assisted laser desorption/ionization time of flight mass spectrometry(MALDI-TOF MS) to characterize shrimp hemolymph peptides.Shrimp serum and plasma were used as the source of samples for comparative analysis,and it was found that serum was more suitable for shrimp hemolymph peptidomic analysis.To screen potential specific biomarkers in serum of immune-challenged shrimps,we applied magnetic bead-based MALDI-TOF MS to serum samples from 10 immune-challenged and 10 healthy shrimps.The spectra were analyzed using FlexAnalysis 3.0 and ClinProTools 2.1 software.Thirteen peptide peaks significantly different between the two groups were selected as candidate biomarkers of lipopolysaccharide(LPS)-infection.The diagnostic model established by genetic algorithm using five of these peaks was able to discriminate LPS-challenged shrimps from healthy control shrimps with a sensitivity of 90% and a specificity of 100%.Our approach in MALDITOF MS-based peptidomics is a powerful tool for screening bioactive peptides or biomarkers derived from hemolymph,and will help to enable a better understanding of the innate immune response of shrimps.
基金Supported by the National Natural Science Foundation of China(Nos.41006084,31172053,31061160187)the Natural Science Foundation of Guangdong Province of China(No.10152408801000013)
文摘We collected five specimens of threadfin bream from Beihai, Guangxi, China in March 2010. These were subsequently identified as red filament threadfin bream Nemipterus marginatus (Valenciennes, 1830), being the first record of this species from Chinese waters. N. marginatus is distinguished by the following characteristics: lower border of eye lies above a line from tip of snout to upper base of pectoral fin; mouth oblique, maxillary extending to lower anterior border of pupil; teeth in jaws in several rows, pointed; upper jaw with 3 to 5 pairs of small recurved canines; suborbital with straight lower edge and rounded posterior edge; pectoral fins extending to between level of anus and origin of anal fin; pelvic fins reaching to the first or second anal rays; caudal fin forked, upper lobe tails into a short reddish filament; dorsal fin bluish with a yellow margin distally and a broad yellow median band which subdivides posteriorly into 3 small bands.
基金Supported by the Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX1-YW-12-03)the National Basic Research Program of China (973 Program) (No. 2006CB403600)+1 种基金China COPES Project (No.GYHY-200706005)the National Natural Science Foundation of China (No. 40821092)
文摘Data assimilation is a powerful tool to improve ocean forecasting by reducing uncertainties in forecast initial conditions.Recently,an ocean data assimilation system based on the ensemble optimal interpolation(EnOI) scheme and HYbrid Coordinate Ocean Model(HYCOM) for marginal seas around China was developed.This system can assimilate both satellite observations of sea surface temperature(SST) and along-track sea level anomaly(SLA) data.The purpose of this study was to evaluate the performance of the system.Two experiments were performed,which spanned a 3-year period from January 1,2004 to December 30,2006,with and without data assimilation.The data assimilation results were promising,with a positive impact on the modeled fields.The SST and SLA were clearly improved in terms of bias and root mean square error over the whole domain.In addition,the assimilations provided improvements in some regions to the surface field where mesoscale processes are not well simulated by the model.Comparisons with surface drifter trajectories showed that assimilated SST and SLA also better represent surface currents,with drifter trajectories fitting better to the contours of SLA field than that without assimilation.The forecasting capacity of this assimilation system was also evaluated through a case study of a birth-and-death process of an anticyclone eddy in the Northern South China Sea(NSCS),in which the anticyclone eddy was successfully hindcasted by the assimilation system.This study suggests the data assimilation system gives reasonable descriptions of the near-surface ocean state and can be applied to forecast mesoscale ocean processes in the marginal seas around China.
基金supported by the basic research and development fund from Institute of Earthquake Science,China Earthquake Administration(grant No.2011IESLZ05)the National Natural Science Foundation of China(grant Nos.40374009and 40904014)
文摘The teleseismic receiver functions of 48 stations belonging to the CCDSN are used to invert the crustal structure beneath each station with the neighborhood algorithm.Thin layers with low velocity have been found beneath eight stations with"abnormal"observed receiver functions.Unreasonable results of few stations have been adjusted lightly with the trial-and-error method.The final result indicates that the crust in the western China is relatively thicker than the eastern China.The crust thickness beneath the Tibetan plateau is very large,which reaches 84 km at the station LSA.Double-crust structure exists below the stations LSA and CAD in Tibet,which might imply the collision between the Indian and Eurasian plates.A pronounced low velocity zone in the lower crust beneath the station TNC of Yunnan province might relate to the high temperature or emergence of partially molten material caused by Quaternary volcano,magma and geothermal activities in this area.The Moho is a transitional zone made up of thin layers instead of simple sharp discontinuity beneath several stations.The Conrad discontinuity is clearly identified beneath 20 stations mainly in the southeastern China,whereas it is blurry beneath 14 stations and uncertain beneath remaining stations.
基金supported by the Foundation of State Key Laboratory of Resources and Environmental Information System (LREIS) (No. 08R8B000SA)the Beijing Commission of Science and Technology (No.D0706007040291-02)the Key Innovation Project of Chinese Academy of Sciences (No. KZCX1-YW-06-03)
文摘A systematic survey of As, Cd, Cr, Cu, Ni, Pb and Zn concentrations in vegetables from 416 samples (involving 100 varieties) in Beijing was carried out for assessing the potential health risk to local inhabitants. The results indicated that the metal concentrations in vegetables ranged from < 0.001 to 0.479 μg/g fresh weight (fw) (As), < 0.001 to 0.101 μg/g fw (Cd), < 0.001 to 1.04 μg/g fw (Cr), 0.024 to 8.25 μg/g fw (Cu), 0.001 to 1.689 μg/g fw (Ni), < 0.001 to 0.655 μg/g fw (Pb) and 0.01 to 25.6 μg/g fw (Zn), with average concentrations of 0.013, 0.010, 0.023, 0.51, 0.053, 0.046 and 2.55 μg/g fw, respectively. The results showed that the concentrations of As, Cr, Cu, Cd, Pb and Ni in vegetables from open-fields were all significantly higher than those grown in greenhouses. In addition, in local-produced vegetables, all HMs except Zn were significantly higher than those in provincial vegetables. The estimated daily intake (EDI) of As, Cd, Cr, Cu, Ni, Pb and Zn from vegetables was 0.080, 0.062, 0.142, 3.14, 0.327, 0.283 and 15.7 μg/(kg body weight (bw)·d) for adults, respectively. Arsenic was the major risk contributor for inhabitants since the target hazard quotient based on the weighted average concentration (THQw) of arsenic amounted to 44.3% of the total THQ (TTHQ) value according to average vegetable consumption. The TTHQ was lower than 1 for all age groups, indicating that it was still safe for the general population of Beijing to consume vegetables.
基金National Natural Science Foundation of China, No.40771031 Thanks are expressed to the Yellow River Conservancy Commission and International Network on Erosion and Sedimentation for the permission of access to hydrometric data. We are also grateful to Dr. Wang Xiujie from Tianjin University for his generous help.
基金National Natural Science Foundation of China, No.40635029 No.40771014
文摘Based on the acquaintance of the regional background of urban-rural transformational development and investigations on the spot,this paper discusses the holistic situation, dominant factors and mechanism of arable land loss and land for construction occupation in the coastal area of China over the last decade,with the aid of GIS technology.Conclusions of the research are summarized as follows:(1)the arable land had been continuously decreasing from 1996 to 2005,with a loss of 1,708,700 hm 2 and an average decrement of 170,900 hm 2 per year;(2)land for construction increased 1,373,700 hm 2 ,with an average increment of 153,200 hm 2 per year;(3)total area of encroachment on arable land for construction between 1996 and 2005 was 1,053,100 hm 2 ,accounting for 34.03%of the arable land loss in the same period,the percentages of which used for industrial land(INL),transportation land(TRL),rural construction land(RUL)and town construction land(TOL)are 45.03%,15.8%,15.47%and 11.5%,respectively;and(4)the fluctuation of the increase of construction land and encroachment on arable land in the area were deeply influenced by the nation's macroscopic land-use policies and development level of regional economy.The growth of population and advancement of technology promoted the rapid industrialization, construction of transportation infrastructures,rural urbanization and expansion of rural settlements in the eastern coastal area,and therefore were the primary driving forces of land-use conversion.
基金Project supported by the National Key Basic Research Support Foundation of China (No.2002CB410810).
文摘A long-term experiment was conducted to investigate how long-term fertilization and rice straw incorporation into soil affect soil glomalin, C and N. The combined application of chemical fertilizer and straw resulted in a significant increase in both soil easily extractable glomalin (EEG) and total glomalin (TG) concentrations, as compared with application of only chemical fertilizer or no fertilizer application. The EEG and TG concentrations of the NPKS (nitrogen, phosphorus, and potassium fertilizer application + rice straw return) plot were 4.68% and 5.67% higher than those of the CK (unfertilized control) plot, and 9.87% and 6.23% higher than those of the NPK (nitrogen, phosphorus, and potassium fertilizer applied annually) plot, respectively. Application of only chemical fertilizer did not cause a statistically significant change of soil glomalin compared with no fertilizer application. The changes of soil organic C (SOC) and total N (TN) contents demonstrated a similar trend to soil glomalin in these plots. The SOC and TN contents of NPKS plot were 15.01% and 9.18% higher than those of the CK plot, and 8.85% and 14.76% higher than those of the NPK plot, respectively. Rice straw return also enhanced the contents of microbial biomass C (MBC) and microbial biomass N (MBN) in the NPKS plot by 7.76% for MBC and 31.42% for MBN compared with the CK plot, and 12.66% for MBC and 15.07% for MBN compared with the NPK plots, respectively. Application of only chemical fertilizer, however, increased MBN concentration, but decreased MBC concentration in soil.
基金supported by grants from the National Basic Research Program of China(2009CB421401/2006CB400503)China Meteorological Administration (GYHY200706001)
文摘Homogenization of climate observations remains a challenge to climate change researchers, especially in cases where metadata (e.g., probable dates of break points) are not always available. To examine the inffuence of metadata on homogenizing climate data, the authors applied the recently developed Multiple Analysis of Series for Homogenization (MASH) method to the Beijing (BJ) daily temperature series for 1960- 2006 in three cases with different references: (1) 13M-considering metadata at BJ and 12 nearby stations; (2) 13NOM-considering the same 13 stations without metadata; and (3) 21NOM-considering 20 further stations and BJ without metadata. The estimated mean annual, seasonal, and monthly inhomogeneities are similar between the 13M and 13NOM cases, while those in the 21NOM case are slightly different. The detected biases in the BJ series corresponding to the documented relocation dates are as low as -0.71~0C, -0.79~0C, and -0.5~0C for the annual mean in the 3 cases, respectively. Other biases, including those undocumented in metadata, are minor. The results suggest that any major inhomogeneity could be detected via MASH, albeit with minor differences in estimating inhomogeneities based on the different references. The adjusted annual series showed a warming trend of 0.337, 0.316, and 0.365~0C (10 yr)^(-1) for the three cases, respectively, smaller than the estimate of 0.453~0C (10 yr)^(-1) in the original series, mainly due to the relocation-induced biases. The impact of the MASH-type homogenization on estimates of climate extremes in the daily temperature series is also discussed.
基金supported by the Knowledge Innovation Program Foundation of the Chinese Academy of Sciences(No. KZCX2-YW-Q10-3,ISSASIP0713)
文摘The adsorption and desorption of Cu(Ⅱ) and Pb(Ⅱ) on upland red soil,and paddy soils which were originated from the upland soil and cultivated for 8,15,35 and 85 years,were investigated using the batch method.The study showed that the organic matter content and cation exchange capacity (CEC) of the soils are important factors controlling the adsorption and desorption of Cu(Ⅱ) and Pb(Ⅱ).The 15-Year paddy soil had the highest adsorption capacity for Pb(Ⅱ),followed by the 35-Year paddy soil.Both the 35-Year paddy soil and 15-Year paddy soil adsorbed more Cu(Ⅱ) than the upland soil and other paddy soils.The 15-Year paddy soils exhibited the highest desorption percentage for both Cu(Ⅱ) and Pb(Ⅱ).These results are consistent with the trend for the CEC of the soils tested.The high soil CEC contributes not only to the adsorption of Cu(Ⅱ) and Pb(Ⅱ) but also to the electrostatic adsorption of the two heavy metals by the soils.Lower desorption percentages for Cu(Ⅱ) (36.7% to 42.2%) and Pb(Ⅱ) (50.4% to 57.9%) were observed for the 85-Year paddy soil.The highest content of organic matter in the soil was responsible for the low desorption percentages for the two metals because the formation of the complexes between the organic matter and the metals could increase the stability of the heavy metals in the soils.
基金supported by the CAS Innovation Key Program (Grant No. KZCX2-YW-BR-14)National Basic Research Program of China (2011CB309704)+1 种基金Special Scientific Research Project for Public Interest (GrantNo. GYHY201006021)the National Natural Science Foundation of China (Grant Nos. 40890155, 40775051,U0733002)
文摘Using the latest daily observational rainfall datasets for the period 1961–2008, the present study investigates the interannual variability of June–September (JJAS) mean rainfall in northern China. The regional characteristics of JJAS mean rainfall are revealed by a rotated empirical orthogonal function (REOF) analysis. The analysis identifies three regions of large interannual variability of JJAS rainfall: North China (NC), Northeast China (NEC), and the Taklimakan Desert in Northwest China (TDNWC). Summer rainfall over NC is shown to have displayed a remarkable dry period from the late 1990s; while over NEC, decadal-scale variation with a significant decreasing trend in the last two decades is found, and over TDNWC, evidence of large interannual variability is revealed. Results also show that the interannual variability of JJAS rainfall in northern China is closely associated with the Northern Hemisphere circumglobal teleconnection (CGT). Correlation coefficients between the CGT index and regional-averaged JJAS mean rainfall over NC and NEC were calculated, revealing values of up to 0.50 and 0.53, respectively, both of which exceeded the 99% confidence level.
基金Under the auspices of Knowledge Innovation Programs of Chinese Academy of Sciences (No.KZCX2-EW-304)National Natural Science Foundation of China (No.40635029,40871257)
文摘The agricultural land resources of China are relatively limited because of its large population.Therefore,balancing the land use for industrialization,urbanization,and food security is a big challenge.In recent years,rural hollowing in China has resulted in numerous of abandoned rural houses,and the areas with abandoned houses need to be restored into agricultural land with effective land consolidation techniques.This study used the method of benefit-cost analysis and the data collected through field surveys conducted in Yucheng City in the northwest of Shandong Province in March 2009,to examine how hollow villages (HVs) to be created and how to solve the problem.The qualitative and quantitative analyses indicate following results.1) The situation of HVs is becoming increasingly severe under rapid industrialization and urbanization in Yucheng City.2) Poor infrastructure in rural areas and incomplete urbanization are the main factors that have led to the rural hollowing in many major rural regions of China.3) In order to resolve the problem caused by HVs and increase agricultural land,reconstructing rural communities in the countryside is necessary.4) A new mechanism in the provision of compensation funds by developed regions to the villages in less-developed regions must be established.
