The study was conducted in Zhifanggou Watershed,Shaanxi Province,China,to evaluate the effect of different vegetation types on hot-water extractable C,N and P fractions,with the aim to determine whether hot-water extr...The study was conducted in Zhifanggou Watershed,Shaanxi Province,China,to evaluate the effect of different vegetation types on hot-water extractable C,N and P fractions,with the aim to determine whether hot-water extractable fractions could be used as indicators of soil quality change in Loess Plateau.The six vegetation types established in 1975 were（i） Robinia pseudoacacia L.,（ii） Caragana korshinkii Kom.,（iii） Pinus tabulaeformis Carr.,（iv） P.tabulaeformis-Amorpha fruticosa L.,（v） R.pseudoacacia-A.fruticosa,and（vi） grassland.A cropped hillslope plot and a Platycladus orientalis L.native forest plot were used as references.The results indicated that the conversion of native forest to cropland resulted in a significant decline in the hot-water extractable C,N and P fractions.Hot-water extractable C,N,and P increased when cultivated land was revegetated,but after 30 years the amount of hot-water extractable C,N,and P in revegetated fields was still much lower compared to native forest.Hot-water extractable fractions increased more under mixed-forest than under pure-forest stands.Furthermore,there was a significant correlation between the hot-water extractable fractions and soil chemical and microbiological properties.The results showed that hot-water extractable fractions could be used as indicators of soil quality change on the Loess Plateau.展开更多
The extraction fraction E and overall volumetric mass transfer coefficient kka of TBP extracting butyric acid pro- cess in confined impinging jet reactors （CIJR） with two jets were investigated. The main variables t...The extraction fraction E and overall volumetric mass transfer coefficient kka of TBP extracting butyric acid pro- cess in confined impinging jet reactors （CIJR） with two jets were investigated. The main variables tested were the concentration of tri-butyl-phosphate （TBP） and butyric acid, the impinging velocity V, the impinging velocityratio of two phases Vorg/Vaq, the nozzle inner diameter di and the distance L between the jet axes and the top wall of the impinging chamber. The results showed that E and kLa increase with an increase of the impinging velocity V, the concentration ofTBP Corg, and the impinging velocity ratio Vor/Vaq. However, E and kta decrease with an increase of the inner diameter d1 from 1 to 2 mm, the concentration of butyric acid Caq from 0.5% （v/v） to 2% （v/v）. The factor L ranging from 3 to 11 mm has a negligible effect on E and kLa. A correlation on these variables and kLa was proposed based on the experimental data. These results indicated good mass transfer oerformance of CIJR in the extraction operation.展开更多
Objective:To evaluate the larvicidal efficacy of crude and fractionated extracts of Dracaena loureiri endocarp against Aedes aegypti,Aedes albopictus,Culex quinquefasciatus,and Anopheles minimus mosquitos.Methods:Larv...Objective:To evaluate the larvicidal efficacy of crude and fractionated extracts of Dracaena loureiri endocarp against Aedes aegypti,Aedes albopictus,Culex quinquefasciatus,and Anopheles minimus mosquitos.Methods:Larvicidal activity was tested according to World Health Organization standard protocol.The third-stage larvae of each mosquito species were exposed to various concentrations of Dracaena loureiri crude extract and six groups of Dracaena loureiri fractionated extracts(RC-DT 009-014).Larval mortality rates were observed after 24 h and48 h of exposure.Then,a computerized probit analysis of the mortality data was performed to determine lethal concentration 50(LC_(50))and lethal concentration 90 values.Results:Anopheles minimus larvae(24-h LC_(50)77.88 mg/L)had the highest susceptibility to crude extract,whereas others(Aedes aegypti,24-h LC_(50)224.73 mg/L;Aedes albopictus,24-h LC_(50)261.75 mg/L;and Culex quinquefasciatus,24-h LC_(50)282.86 mg/L)were significantly less susceptible.The most effective groups of fractionated extracts were RC-DT 012 and RC-DT 013.The mosquito species most susceptible to fractionated extracts was Culex quinquefasciatus,with 24-h LC_(50)values of 0.66 and 0.94 mg/L for RC-DT 012 and RC-DT 013,respectively.Conclusions:The larvicidal activity of fractionated extracts is more effective than that of crude extract against all tested mosquito species.For the most effective alternative larvicide,purification and a phytochemical constituent analysis must be performed.展开更多
Datong coal was extracted with CS2, n-hexane, benzene, methanol, acetone, tetrahydro-furan（THF） and THF/methanol（1：3,v/v） mixed solvent sequentially. The extracts were analyzed with GC/MS. It is presented that gr...Datong coal was extracted with CS2, n-hexane, benzene, methanol, acetone, tetrahydro-furan（THF） and THF/methanol（1：3,v/v） mixed solvent sequentially. The extracts were analyzed with GC/MS. It is presented that group seperation of soluble organic compounds in the coal can be achieved by fractionated extraction using different solvents. The results show that CS2 was effective for extracting arenes from the coal sample, n-Hexane extractable fraction from Datong coal mainly consists of n-alkanes. A great variety of oxygen-containing compounds are dominant in the components of methanol-soluble fraction. Acyclic isoprenoids, pentecyclic triterpanes and a series of cyclohexanes with long-chain alkyl-substitutes are detected in acetone-soluble fraction. Dicyclic aramatic hydrocarbons are identified in benzene-soluble fraction and 4-6 cyclic condensed aramatic hydrocarbons are identified in THF-soluble fraction. The molecular structures detection of 1,2-dichlorobenzene, 2,4-dibromophnol, 2,4,6-tribromophenol and 4-chlorobenzophenone firstly provide information for existence form of bromine and chlorine in coal.展开更多
Shenfu coal was extracted with 0S2, n-hexane, benzene sequentially. The extracts were analyzed with GC/MS. It is presented that group seperation of soluble organic compounds in the coal can be achieved by fractionated...Shenfu coal was extracted with 0S2, n-hexane, benzene sequentially. The extracts were analyzed with GC/MS. It is presented that group seperation of soluble organic compounds in the coal can be achieved by fractionated extraction using different solvents. Main components in CS2 soluble fraction from Shenfu coal are alkyl-substituted arenes. Aliphatic hydrocarbons are overwhelmingly predominant in n-hexane-soluble fraction. Dito tricyclic aramatic hydrocarbons are identified in benzene-soluble fraction. The molecular structures detection of 2, 4, 6-trichlorobenzenamine and 3, 3＇, 4, 4＇, 5, 5＇-hexachloro-1, 1＇- biphenyl and 2-chlorocyclohexanol firstly provide information for existence form of chlorine in coal.展开更多
Objective:To evaluate the in vivo trypanocidal activity of the methanol extract and fractions of Abrus precatorius seeds in mice.Methods:Parasiteamia was induced unto mice by intraperitoneal injection of 1.25×10&...Objective:To evaluate the in vivo trypanocidal activity of the methanol extract and fractions of Abrus precatorius seeds in mice.Methods:Parasiteamia was induced unto mice by intraperitoneal injection of 1.25×10<sup>5</sup> Trypanosoma in normal saline.Five days when a high level of parasiteamia was established treatment commenced until ten days.The mice were treated with 10,20 and 40 mg/kg bt.of the extract and 5 and 10 mg/kg bt.of the fraction（F<sub>2</sub>）,respectively for 5 days.Diminazene acelurate at the dose of 3.5 mg/kg bt.for two days was used as the reference drug.The level of parasitaemia and packed cell volume（PCV） of the animals estimated. Results:At doses of 10,20 and 40 mg/kg the crude extract showed a sharp reduction in the level of parasitaemia in mice compared with the untreated group.The mice treated with F,at doses of 5 and 10 mg/kg showed a sharp reduction in the level of parasitamia to zero in day 9,and a gradual recovery from the 12th day of treatment.This effect is comparable to that of the mice treated with 7 mg/kg of standard drug diminazene aceturate.The PCV of the treated showed a gradual decrease with time,but not as much as the untreated group.Phytochemical screening revealed the presence of glycosides,alkaloids,carbohydrates,tannins and proteins in the Abrus precatorius powder while F<sub>2</sub> was rich in alkaloids.Conclusions:This study shows that both the extract and the fractions of Abrus precatorius seeds exhibited a promising trypanocidal property.Alkaloids may be responsible for the observed activity.展开更多
Surface and subsurface oil shale (OS) rocks in Jordan have potential economic value for the country and still unutilized. This research paper focuses on central and southern OS deposits in Jordan. Brief characterizati...Surface and subsurface oil shale (OS) rocks in Jordan have potential economic value for the country and still unutilized. This research paper focuses on central and southern OS deposits in Jordan. Brief characterization of four OS deposits is presented. Size distribution test and elemental analysis were performed. Shale oil was extracted via three solvation methods: Soxhlet extraction, extraction via mixing and stirring, and lastly super-critical fluid extraction. Major shale oil fractions were obtained from extract fractionation on chromatographic column. The nuclear magnetic resonance spectroscopy technique was used to study qualitatively the fractional composition of OS extract. Results show that all studied OS deposits have quite similar trend in their particle size distribution and their elemental composition. These OS deposits are found to be varying in their solvation behavior, fractional yield, and shale oil composition. Highest yield is obtained from polar solvents. The OS extraction via solvation processes is promising under certain extraction conditions such as super-critical conditions. The solvation variability of Jordanian OS indicates that different extraction techniques suit different OS deposits. Such variability should be considered in any future extraction options.展开更多
Based on chemical thermodynamics and mass balance,countercurrently fractional chiral extraction by hollow fiber membrane was investigated.The mathematical modules for the relation of chiral extraction yield and produc...Based on chemical thermodynamics and mass balance,countercurrently fractional chiral extraction by hollow fiber membrane was investigated.The mathematical modules for the relation of chiral extraction yield and product optical purity with number of transfer units by chiral extraction with hollow fiber membrane were established,and the modules were simulated by visual basic(VB)proceduce.The results show that,the difference in free energy between two diastereomeric complexes formed by R-and S-enantiomer with chiral selector,??(?G),is the force of separation of enantiomers.It is necessary to separate enantiomers,where one of the extraction factors is above 1,and the other is below 1.Under certain phase ratio,chiral separation depends on separation factor and number of transfer units.The experimental result is in agreement with the theoretical value.展开更多
Alpinia oxyphylla,a traditional herb,is widely used for its neuroprotective,antioxidant and memory-improving effects.However,the neuroprotective mechanisms of action of its active ingredients are unclear.In this study...Alpinia oxyphylla,a traditional herb,is widely used for its neuroprotective,antioxidant and memory-improving effects.However,the neuroprotective mechanisms of action of its active ingredients are unclear.In this study,we investigated the neuroprotective effects of various organic extracts of Alpinia oxyphylla on PC12 cells exposed to hydrogen peroxide-induced oxidative injury in vitro.Alpinia oxyphylla was extracted three times with 95%ethanol(representing extracts 1–3).The third 95%ethanol extract was dried and resuspended in water,and then extracted successively with petroleum ether,ethyl acetate and n-butanol(representing extracts 4–6).The cell counting kit-8 assay and microscopy were used to evaluate cell viability and observe the morphology of PC12 cells.The protective effect of the three ethanol extracts(at tested concentrations of 50,100 and 200μg/mL)against cytotoxicity to PC12 cells increased in a concentration-dependent manner.The ethyl acetate,petroleum ether and n-butanol extracts(each tested at 100,150 and 200μg/mL)had neuroprotective effects as well.The optimum effective concentration ranged from 50–200μg/mL,and the protective effect of the ethyl acetate extract was comparatively robust.These results demonstrate that organic extracts of Alpinia oxyphylla protect PC12 cells against apoptosis induced by hydrogen peroxide.Our findings should help identify the bioactive neuroprotective components in Alpinia oxyphylla.展开更多
The vacuum residual from Iranian Light crude oil are separated into a series of 16 narrow fractions according to the molecular weight by the supercritical fluid extraction and fractional (SFEF) technology. The chemica...The vacuum residual from Iranian Light crude oil are separated into a series of 16 narrow fractions according to the molecular weight by the supercritical fluid extraction and fractional (SFEF) technology. The chemical element and the UV spectrum of each fraction are analyzed. The effects of several factors on the interfacial tension are investigated, which are the fraction concentration in oil phase, the ratio of oil component, the salts dissolved in the water phase and the pH value. The interfacial tension decreases rapidly as the concentration of the residual fraction in the oil increases, showing a higher interfacial activity of the fraction. The interfacial tension changes, as the amount of absorption or the state of the fractions in the interface changes resulting from different ratios of oil, different kinds or concentrations of salts in water, and different pH values. It is concluded that the interfacial tension changes regularly, corresponding to the regular molecular parameters of the vacuum residual fractions.展开更多
The amounts and forms of phosphorus （P） in surface sediments of Haihe River, Tianjin, North China, were examined using a sequential chemical extraction procedure. Five fractions of sedimentary P, including loosely s...The amounts and forms of phosphorus （P） in surface sediments of Haihe River, Tianjin, North China, were examined using a sequential chemical extraction procedure. Five fractions of sedimentary P, including loosely sorbed P （NH4Cl-P）, redox-sensitive P （BD-P）, metal oxide bound P （NaOH-P）, calcium bound P （HCI-P）, and residual P （Res-P） （organic and refractory P）, were separately quantified. The results indicated that the contents of different P fractions in the sediments varied greatly. The total P （TP） contents ranged from 968 to 2017 mg/kg. Phosphorus contents in NH4Cl-P, BD-P, NaOH-P, and HCl-P ranged from 6.7 to 26.6 mg/kg, 54.5 to 90.2 mg/kg, 185.2 to 382.5 mg/kg, and 252.3 to 425.5 mg/kg, respectively, which represented 1.2%-3.2%, 7.7%-13%, 33.3%-48.9%, and 36.2%-54.2% of the sedimentary inorganic P, respectively. For all the sediment samples, the rank order of P-fractions was Res-P 〉 HCl-P 〉 NaOH-P 〉 BD-P 〉 NH4Cl-P. The highly positive relationship between the amounts of P released from the sediments and those in the NH4Cl-P and BD-P fractions, indicated that NH4Cl-P and BD-P were the main fractions that can release P easily.展开更多
In order to characterize the organic properties of waste activated sludge in a wastewater treatment plant,organic matter within sludge was extracted with NH 3 ·H 2 O preferentially,and subsequently fractionated i...In order to characterize the organic properties of waste activated sludge in a wastewater treatment plant,organic matter within sludge was extracted with NH 3 ·H 2 O preferentially,and subsequently fractionated into five fractions using XAD-8/XAD-4 resins.Up to a 63.8%-71.1% of organic matter within the sludge could be efficiently extracted by NH 3 ·H 2 O.Fractionation results showed that hydrophobic acid and hydrophilic fraction were two main components among the sludge organic matter （accounting for 32.2% and 48.0% of the bulk organic matter,respectively）,whereas transphilic acid,hydrophobic neutral and transphilic neutral were quite low （accounting for 9.2%,5.8% and 4.8%,respectively）.Despite that the extractant of NH 3 ·H 2 O showed a relatively higher extraction efficiency of the aromatic components,the relatively low aromaticity of the organic fractions implied that those non-aromatic components could also be effectively extracted,especially for neutral and hydrophilic fractions.In addition,acidic fractions contained more aromatic humic-like components,whereas the neutral fractions had a greater content of aromatic proteins and soluble microbial byproduct-like components.Extraction of sludge organics with NH3·H2O and subsequential fractionation using XAD resins could be a novel method for further characterization of sludge organics.展开更多
Modified BCR sequential extraction, single equilibrium-based EDTA extraction and kinetic fractionation were used for estimating the Pb and Cd availability in a series of soil samples from 3 sites located in urban area...Modified BCR sequential extraction, single equilibrium-based EDTA extraction and kinetic fractionation were used for estimating the Pb and Cd availability in a series of soil samples from 3 sites located in urban areas of Hanoi (Vietnam). These schemes were compared to identify a simple, rapid and cheap protocol for routine estimation of Pb and Cd remobilizable fraction and the related potential risk. The comparison of these three approaches revealed their convergence in terms of mobility patterns observed for Pb and Cd. Cd was characterized by higher extractibality and mobility whatever the approach. Pb was distinguished of Cd by its high association to Feoxides, lower extractability, lower rate of desorption and then lower mobility. For this environmental scenario, EDTA single scheme at equilibrium could be suggested as the best suited and a simple protocol for determination of the labile pool of Cd and Pb. The pseudo-total concentrations of Pb and Cd are actually below the Vietnamese standard level, contrary to the results obtained by other authors for agricultural soils at other urban sites of Hanoi.展开更多
Noroviruses are the most common cause of acute gastroenteritis. Annually, 21 million Americans are infected with norovirus. Recent advances in molecular diagnostics have helped to establish norovirus as the most commo...Noroviruses are the most common cause of acute gastroenteritis. Annually, 21 million Americans are infected with norovirus. Recent advances in molecular diagnostics have helped to establish norovirus as the most common cause of outbreaks of acute gastroenteritis across all ages. However, there is no effective or efficient treatment/control against norovirus infection. Conventional intervention techniques used to inactivate norovirus have shown lack of efficacy against human norovirus. Currently, effective treatment or control measures against human norovirus have not been identified. In this study, murine norovirus acts as a model to human norovirus to evaluate the inhibitory effects of crude extracts of Zanthoxylum armatum and Hibiscus sabdariffa. The study also separated, identified and quantified the selected compounds using the ultra-liquid chromatography (UPLC). To study the antiviral activities of crude extracts and its fractionated portions of Z. armatum and H. sabdariffa against norovirus surrogate, RAW 264.7 cells were infected with Murine norovirus surrogate virus of human norovirus and incubated at 37?C. Phytochemicals were extracted from the seeds and calyces of the plants using methanolic extraction. Fractionated portions of the crude extracts were subsequently used in both chromatographic and microbiological studies. Our data indicated that there was reduction of viruses, when treated with the 60% aqueous methanol extracts. Amongst the four selected phenolic compounds (myricetin, quercetin, kaempferol and luteolin), quercetin showed the most significant logarithmic viral reductions. These compounds were identified, purified and quantified using UPLC. Extracts of Zanthoxylum armatum and Hibiscus sabdariffa showed antiviral effects. Phenolic compounds are virucidal. Extracts of Hibiscus sabdariffa also exhibits anti-norovirus activities. The results are anticipated to control/prevent the human norovirus infections.展开更多
In most arid and semiarid soils, naturally occurring phosphorus(P) is a major yield-limiting plant nutrient. In this study, to investigate the effects of organic(OP) and inorganic P(IP) sources on P fractionation, a c...In most arid and semiarid soils, naturally occurring phosphorus(P) is a major yield-limiting plant nutrient. In this study, to investigate the effects of organic(OP) and inorganic P(IP) sources on P fractionation, a calcareous sandy loam alkaline soil was fertilized with OP and IP fertilizers at low(80 mg P kg^(-1) soil) and high(160 mg P kg^(-1) soil) application rates. Three combinations of OP and IP(i.e., 75% OP + 25% IP, 50% OP + 50% IP, and 25% OP + 75% IP) were applied at low and high application rates,respectively, followed by soil aging for 21 d. Soil samples were collected after 1, 2, 3, 7, and 21 d and subjected to sequential extraction to analyze soluble and exchangeable, Fe-and Al-bound, Ca-bound, and residual P fractions. The soluble and exchangeable P fraction significantly increased up to 24.3%, whereas the Ca-bound fraction decreased up to 40.7% in the soils receiving 75% OP + 25% IP and 50% OP + 50% IP, respectively, compared with the control(receiving no P fertilizer). However, the transformation of P fractions was influenced by aging time. Addition of P sources caused instant changes in different P fractions, which then tended to decline with aging time. Change in soil p H was the limiting factor in controlling P availability. At high application rate, the OP source significantly increased soil P availability compared with the IP source with soil aging. Depending on P fractionation, a proper combination of OP and IP fertilizers, as long-term slow and instant P-releasing sources for plant uptake, respectively, may be a sustainable strategy to meet crop P requirements in the arid and semiarid soils.展开更多
Aqueous extracts from various plant parts of fenugreek(3%)(aerial parts:leaves and stems(LS),roots(R),ground seeds(GS)and not ground seeds(NGS))and petroleum ether,ethyl acetate and methanolic fractions of the aerial ...Aqueous extracts from various plant parts of fenugreek(3%)(aerial parts:leaves and stems(LS),roots(R),ground seeds(GS)and not ground seeds(NGS))and petroleum ether,ethyl acetate and methanolic fractions of the aerial parts were assayed to determine their antifungal potential against Botrytis cinerea,Fusarium graminearum,Alternaria sp.,Pythium aphanidermatum,and Rhizoctinia solani.All fenugreek plant parts showed antifungal potential and the magnitude of their inhibitory effects was species and plant parts d...展开更多
In urban waste (the first matter of compost), elements such as copper, nickel and lead may be found in metallic state (wire, pile, accumulator, etc.), which is considered as non-dependent state. The work undertaken at...In urban waste (the first matter of compost), elements such as copper, nickel and lead may be found in metallic state (wire, pile, accumulator, etc.), which is considered as non-dependent state. The work undertaken at the laboratory of composting of the INRST in Henchir Lihoudia (Tunis) showed that the produced compost does not contain any mobile metallic element and the portion related to organic fraction (bioavailable) is tiny in size. We supposed that many reactions involving decomposition and complexation from elements related to the matrix components occurred during composting. The existence and importance of this phenomenon can be evaluated by studying the evolution of metal contents in the different fractions extracted sequentially during composting process.展开更多
Grape pomace is the main by-product of wine production that concentrates bioactive metabolites of polyphenolic nature with antibacterial activity. Since grape pomace composition varied depending on grape variety, clim...Grape pomace is the main by-product of wine production that concentrates bioactive metabolites of polyphenolic nature with antibacterial activity. Since grape pomace composition varied depending on grape variety, climate, vineyard location, and winemaking technology, it is important to study the composition and antibacterial activity of each variety separately. In this study, antibacterial activity against different food pathogens was evaluated and its relation with polyphenols content was determined. Grape pomace from Cabernet Sauvignon and Syrah varieties was extracted with methanol/HCl 1% (v/v), followed by sequential extractions with hexane, chloroform and ethyl acetate. Ethyl acetate fraction had the highest antibacterial activity determined through the microdilution method, reaching over 90% of inhibition at 500 μg·ml-1 with the exception of Salmonella Typhi (70% of inhibition). Staphylococcus aureus and Escherichia coli were the most susceptible strains, exceeding 50% of inhibition at 62.5 μg·ml-1. Ethyl acetate fraction contains the highest phenolic concentration in both Cabernet Sauvignon (132.2 mg of GAE g-1) and Syrah (102.6 mg of GAE g-1) pomace, as determined by the Folin-Ciocalteau method. Antibacterial activity present in grape pomace extracts is in direct relation to the polar phenolic content, in particular that from Cabernet Sauvignon.展开更多
Most image saliency detection models are dependent on prior knowledge and demand high computational cost. However, spectral residual（SR） and phase spectrum of the Fourier transform（PFT） models are simple and fast ...Most image saliency detection models are dependent on prior knowledge and demand high computational cost. However, spectral residual（SR） and phase spectrum of the Fourier transform（PFT） models are simple and fast saliency detection approaches based on two-dimensional Fourier transform without the prior knowledge. For seismic data, the geological structure of the underground rock formation changes more obviously in the time direction. Therefore, one-dimensional Fourier transform is more suitable for seismic saliency detection. Fractional Fourier transform（FrFT） is an improved algorithm for Fourier transform, therefore we propose the seismic SR and PFT models in one-dimensional FrF T domain to obtain more detailed saliency maps. These two models use the amplitude and phase information in FrFT domain to construct the corresponding saliency maps in spatial domain. By means of these two models, several saliency maps at different fractional orders can be obtained for seismic attribute analysis. These saliency maps can characterize the detailed features and highlight the object areas, which is more conducive to determine the location of reservoirs. The performance of the proposed method is assessed on both simulated and real seismic data. The results indicate that our method is effective and convenient for seismic attribute extraction with good noise immunity.展开更多
基金financially supported by the Strategic Technology Project of Chinese Academy of Sciences,China(XDA05060300)the Science and Technology Research and Development Program of Shaanxi Province,China(2011KJXX63)the Fundamental Research Funds for the Central Universities,China(ZD2013021)
文摘The study was conducted in Zhifanggou Watershed,Shaanxi Province,China,to evaluate the effect of different vegetation types on hot-water extractable C,N and P fractions,with the aim to determine whether hot-water extractable fractions could be used as indicators of soil quality change in Loess Plateau.The six vegetation types established in 1975 were（i） Robinia pseudoacacia L.,（ii） Caragana korshinkii Kom.,（iii） Pinus tabulaeformis Carr.,（iv） P.tabulaeformis-Amorpha fruticosa L.,（v） R.pseudoacacia-A.fruticosa,and（vi） grassland.A cropped hillslope plot and a Platycladus orientalis L.native forest plot were used as references.The results indicated that the conversion of native forest to cropland resulted in a significant decline in the hot-water extractable C,N and P fractions.Hot-water extractable C,N,and P increased when cultivated land was revegetated,but after 30 years the amount of hot-water extractable C,N,and P in revegetated fields was still much lower compared to native forest.Hot-water extractable fractions increased more under mixed-forest than under pure-forest stands.Furthermore,there was a significant correlation between the hot-water extractable fractions and soil chemical and microbiological properties.The results showed that hot-water extractable fractions could be used as indicators of soil quality change on the Loess Plateau.
基金Supported by the National Natural Science Foundation of China(21206002,21376016)the State Key Laboratory of Chemical Engineering(SKL-Ch E-13A03)
文摘The extraction fraction E and overall volumetric mass transfer coefficient kka of TBP extracting butyric acid pro- cess in confined impinging jet reactors （CIJR） with two jets were investigated. The main variables tested were the concentration of tri-butyl-phosphate （TBP） and butyric acid, the impinging velocity V, the impinging velocityratio of two phases Vorg/Vaq, the nozzle inner diameter di and the distance L between the jet axes and the top wall of the impinging chamber. The results showed that E and kLa increase with an increase of the impinging velocity V, the concentration ofTBP Corg, and the impinging velocity ratio Vor/Vaq. However, E and kta decrease with an increase of the inner diameter d1 from 1 to 2 mm, the concentration of butyric acid Caq from 0.5% （v/v） to 2% （v/v）. The factor L ranging from 3 to 11 mm has a negligible effect on E and kLa. A correlation on these variables and kLa was proposed based on the experimental data. These results indicated good mass transfer oerformance of CIJR in the extraction operation.
基金supported by the Naresuan University Research Fund(Reference Number:R2560B057)
文摘Objective:To evaluate the larvicidal efficacy of crude and fractionated extracts of Dracaena loureiri endocarp against Aedes aegypti,Aedes albopictus,Culex quinquefasciatus,and Anopheles minimus mosquitos.Methods:Larvicidal activity was tested according to World Health Organization standard protocol.The third-stage larvae of each mosquito species were exposed to various concentrations of Dracaena loureiri crude extract and six groups of Dracaena loureiri fractionated extracts(RC-DT 009-014).Larval mortality rates were observed after 24 h and48 h of exposure.Then,a computerized probit analysis of the mortality data was performed to determine lethal concentration 50(LC_(50))and lethal concentration 90 values.Results:Anopheles minimus larvae(24-h LC_(50)77.88 mg/L)had the highest susceptibility to crude extract,whereas others(Aedes aegypti,24-h LC_(50)224.73 mg/L;Aedes albopictus,24-h LC_(50)261.75 mg/L;and Culex quinquefasciatus,24-h LC_(50)282.86 mg/L)were significantly less susceptible.The most effective groups of fractionated extracts were RC-DT 012 and RC-DT 013.The mosquito species most susceptible to fractionated extracts was Culex quinquefasciatus,with 24-h LC_(50)values of 0.66 and 0.94 mg/L for RC-DT 012 and RC-DT 013,respectively.Conclusions:The larvicidal activity of fractionated extracts is more effective than that of crude extract against all tested mosquito species.For the most effective alternative larvicide,purification and a phytochemical constituent analysis must be performed.
基金Projects 20076051, G1999022101, and 98029016 supported by National Natural Science Foundation of China, the Special Found for Major State BasicResearch Project, and Research Found for the Doctoral Program of Higher Education
文摘Datong coal was extracted with CS2, n-hexane, benzene, methanol, acetone, tetrahydro-furan（THF） and THF/methanol（1：3,v/v） mixed solvent sequentially. The extracts were analyzed with GC/MS. It is presented that group seperation of soluble organic compounds in the coal can be achieved by fractionated extraction using different solvents. The results show that CS2 was effective for extracting arenes from the coal sample, n-Hexane extractable fraction from Datong coal mainly consists of n-alkanes. A great variety of oxygen-containing compounds are dominant in the components of methanol-soluble fraction. Acyclic isoprenoids, pentecyclic triterpanes and a series of cyclohexanes with long-chain alkyl-substitutes are detected in acetone-soluble fraction. Dicyclic aramatic hydrocarbons are identified in benzene-soluble fraction and 4-6 cyclic condensed aramatic hydrocarbons are identified in THF-soluble fraction. The molecular structures detection of 1,2-dichlorobenzene, 2,4-dibromophnol, 2,4,6-tribromophenol and 4-chlorobenzophenone firstly provide information for existence form of bromine and chlorine in coal.
基金the National Natural Science Foundation(20076051)the Special Fund for Major State Basic Research Project(G1999022101)the Research Fund for the Doctoral Program of Higher Education(98029016)
文摘Shenfu coal was extracted with 0S2, n-hexane, benzene sequentially. The extracts were analyzed with GC/MS. It is presented that group seperation of soluble organic compounds in the coal can be achieved by fractionated extraction using different solvents. Main components in CS2 soluble fraction from Shenfu coal are alkyl-substituted arenes. Aliphatic hydrocarbons are overwhelmingly predominant in n-hexane-soluble fraction. Dito tricyclic aramatic hydrocarbons are identified in benzene-soluble fraction. The molecular structures detection of 2, 4, 6-trichlorobenzenamine and 3, 3＇, 4, 4＇, 5, 5＇-hexachloro-1, 1＇- biphenyl and 2-chlorocyclohexanol firstly provide information for existence form of chlorine in coal.
文摘Objective:To evaluate the in vivo trypanocidal activity of the methanol extract and fractions of Abrus precatorius seeds in mice.Methods:Parasiteamia was induced unto mice by intraperitoneal injection of 1.25×10<sup>5</sup> Trypanosoma in normal saline.Five days when a high level of parasiteamia was established treatment commenced until ten days.The mice were treated with 10,20 and 40 mg/kg bt.of the extract and 5 and 10 mg/kg bt.of the fraction（F<sub>2</sub>）,respectively for 5 days.Diminazene acelurate at the dose of 3.5 mg/kg bt.for two days was used as the reference drug.The level of parasitaemia and packed cell volume（PCV） of the animals estimated. Results:At doses of 10,20 and 40 mg/kg the crude extract showed a sharp reduction in the level of parasitaemia in mice compared with the untreated group.The mice treated with F,at doses of 5 and 10 mg/kg showed a sharp reduction in the level of parasitamia to zero in day 9,and a gradual recovery from the 12th day of treatment.This effect is comparable to that of the mice treated with 7 mg/kg of standard drug diminazene aceturate.The PCV of the treated showed a gradual decrease with time,but not as much as the untreated group.Phytochemical screening revealed the presence of glycosides,alkaloids,carbohydrates,tannins and proteins in the Abrus precatorius powder while F<sub>2</sub> was rich in alkaloids.Conclusions:This study shows that both the extract and the fractions of Abrus precatorius seeds exhibited a promising trypanocidal property.Alkaloids may be responsible for the observed activity.
文摘Surface and subsurface oil shale (OS) rocks in Jordan have potential economic value for the country and still unutilized. This research paper focuses on central and southern OS deposits in Jordan. Brief characterization of four OS deposits is presented. Size distribution test and elemental analysis were performed. Shale oil was extracted via three solvation methods: Soxhlet extraction, extraction via mixing and stirring, and lastly super-critical fluid extraction. Major shale oil fractions were obtained from extract fractionation on chromatographic column. The nuclear magnetic resonance spectroscopy technique was used to study qualitatively the fractional composition of OS extract. Results show that all studied OS deposits have quite similar trend in their particle size distribution and their elemental composition. These OS deposits are found to be varying in their solvation behavior, fractional yield, and shale oil composition. Highest yield is obtained from polar solvents. The OS extraction via solvation processes is promising under certain extraction conditions such as super-critical conditions. The solvation variability of Jordanian OS indicates that different extraction techniques suit different OS deposits. Such variability should be considered in any future extraction options.
基金Project(20576029) supported by the National Natural Science Foundation of ChinaProject(2004035650) supported by the China Postdoctoral Science Foundation
文摘Based on chemical thermodynamics and mass balance,countercurrently fractional chiral extraction by hollow fiber membrane was investigated.The mathematical modules for the relation of chiral extraction yield and product optical purity with number of transfer units by chiral extraction with hollow fiber membrane were established,and the modules were simulated by visual basic(VB)proceduce.The results show that,the difference in free energy between two diastereomeric complexes formed by R-and S-enantiomer with chiral selector,??(?G),is the force of separation of enantiomers.It is necessary to separate enantiomers,where one of the extraction factors is above 1,and the other is below 1.Under certain phase ratio,chiral separation depends on separation factor and number of transfer units.The experimental result is in agreement with the theoretical value.
基金financially supported by the National Natural Science Foundation of China,No.81574038(to ZZW)the Natural Science Foundation of Guangdong Province of China,No.2017A030313842(to LHD)+1 种基金the Science and Technology Foundation of Guangdong Province of China,No.2017A050506007(to YHL)the Technology Research Foundation of Basic Research Project of Shenzhen City of China,No.JCYJ20170412161254416(to ZZW)
文摘Alpinia oxyphylla,a traditional herb,is widely used for its neuroprotective,antioxidant and memory-improving effects.However,the neuroprotective mechanisms of action of its active ingredients are unclear.In this study,we investigated the neuroprotective effects of various organic extracts of Alpinia oxyphylla on PC12 cells exposed to hydrogen peroxide-induced oxidative injury in vitro.Alpinia oxyphylla was extracted three times with 95%ethanol(representing extracts 1–3).The third 95%ethanol extract was dried and resuspended in water,and then extracted successively with petroleum ether,ethyl acetate and n-butanol(representing extracts 4–6).The cell counting kit-8 assay and microscopy were used to evaluate cell viability and observe the morphology of PC12 cells.The protective effect of the three ethanol extracts(at tested concentrations of 50,100 and 200μg/mL)against cytotoxicity to PC12 cells increased in a concentration-dependent manner.The ethyl acetate,petroleum ether and n-butanol extracts(each tested at 100,150 and 200μg/mL)had neuroprotective effects as well.The optimum effective concentration ranged from 50–200μg/mL,and the protective effect of the ethyl acetate extract was comparatively robust.These results demonstrate that organic extracts of Alpinia oxyphylla protect PC12 cells against apoptosis induced by hydrogen peroxide.Our findings should help identify the bioactive neuroprotective components in Alpinia oxyphylla.
基金Supported by the National Key Basic Research Programme (No.973-G1999022505),University of Petroleum Basic Research Fund(No.ZX9904)
文摘The vacuum residual from Iranian Light crude oil are separated into a series of 16 narrow fractions according to the molecular weight by the supercritical fluid extraction and fractional (SFEF) technology. The chemical element and the UV spectrum of each fraction are analyzed. The effects of several factors on the interfacial tension are investigated, which are the fraction concentration in oil phase, the ratio of oil component, the salts dissolved in the water phase and the pH value. The interfacial tension decreases rapidly as the concentration of the residual fraction in the oil increases, showing a higher interfacial activity of the fraction. The interfacial tension changes, as the amount of absorption or the state of the fractions in the interface changes resulting from different ratios of oil, different kinds or concentrations of salts in water, and different pH values. It is concluded that the interfacial tension changes regularly, corresponding to the regular molecular parameters of the vacuum residual fractions.
基金supported by the Natural Science Foun-dation of Tianjin (No. 09YFSZSF02100)the National Natural Science Foundation of China (No. 50479034)the Commonweal Projects of the Water Conservancy of China (No. 200801135)
文摘The amounts and forms of phosphorus （P） in surface sediments of Haihe River, Tianjin, North China, were examined using a sequential chemical extraction procedure. Five fractions of sedimentary P, including loosely sorbed P （NH4Cl-P）, redox-sensitive P （BD-P）, metal oxide bound P （NaOH-P）, calcium bound P （HCI-P）, and residual P （Res-P） （organic and refractory P）, were separately quantified. The results indicated that the contents of different P fractions in the sediments varied greatly. The total P （TP） contents ranged from 968 to 2017 mg/kg. Phosphorus contents in NH4Cl-P, BD-P, NaOH-P, and HCl-P ranged from 6.7 to 26.6 mg/kg, 54.5 to 90.2 mg/kg, 185.2 to 382.5 mg/kg, and 252.3 to 425.5 mg/kg, respectively, which represented 1.2%-3.2%, 7.7%-13%, 33.3%-48.9%, and 36.2%-54.2% of the sedimentary inorganic P, respectively. For all the sediment samples, the rank order of P-fractions was Res-P 〉 HCl-P 〉 NaOH-P 〉 BD-P 〉 NH4Cl-P. The highly positive relationship between the amounts of P released from the sediments and those in the NH4Cl-P and BD-P fractions, indicated that NH4Cl-P and BD-P were the main fractions that can release P easily.
基金supported by the National Nature Science Foundation of China (National Creative Research Groups) (No. 50821002)the State Key Laboratory of Urban Water Resource and Environment,Harbin Instituteof Technology (No. 2008DX05)+2 种基金the Key Projects in the National Science and Technology Pillar Program during the Eleventh Five-year Plan Period (No. 2006BAC19B04)the Heilongjiang Province Science Foundation for Youths(No. QC2009C113/E0804)the Shanghai Tongji GaoTingyao Environmental Science & Technology Development Foundation
文摘In order to characterize the organic properties of waste activated sludge in a wastewater treatment plant,organic matter within sludge was extracted with NH 3 ·H 2 O preferentially,and subsequently fractionated into five fractions using XAD-8/XAD-4 resins.Up to a 63.8%-71.1% of organic matter within the sludge could be efficiently extracted by NH 3 ·H 2 O.Fractionation results showed that hydrophobic acid and hydrophilic fraction were two main components among the sludge organic matter （accounting for 32.2% and 48.0% of the bulk organic matter,respectively）,whereas transphilic acid,hydrophobic neutral and transphilic neutral were quite low （accounting for 9.2%,5.8% and 4.8%,respectively）.Despite that the extractant of NH 3 ·H 2 O showed a relatively higher extraction efficiency of the aromatic components,the relatively low aromaticity of the organic fractions implied that those non-aromatic components could also be effectively extracted,especially for neutral and hydrophilic fractions.In addition,acidic fractions contained more aromatic humic-like components,whereas the neutral fractions had a greater content of aromatic proteins and soluble microbial byproduct-like components.Extraction of sludge organics with NH3·H2O and subsequential fractionation using XAD resins could be a novel method for further characterization of sludge organics.
文摘Modified BCR sequential extraction, single equilibrium-based EDTA extraction and kinetic fractionation were used for estimating the Pb and Cd availability in a series of soil samples from 3 sites located in urban areas of Hanoi (Vietnam). These schemes were compared to identify a simple, rapid and cheap protocol for routine estimation of Pb and Cd remobilizable fraction and the related potential risk. The comparison of these three approaches revealed their convergence in terms of mobility patterns observed for Pb and Cd. Cd was characterized by higher extractibality and mobility whatever the approach. Pb was distinguished of Cd by its high association to Feoxides, lower extractability, lower rate of desorption and then lower mobility. For this environmental scenario, EDTA single scheme at equilibrium could be suggested as the best suited and a simple protocol for determination of the labile pool of Cd and Pb. The pseudo-total concentrations of Pb and Cd are actually below the Vietnamese standard level, contrary to the results obtained by other authors for agricultural soils at other urban sites of Hanoi.
文摘Noroviruses are the most common cause of acute gastroenteritis. Annually, 21 million Americans are infected with norovirus. Recent advances in molecular diagnostics have helped to establish norovirus as the most common cause of outbreaks of acute gastroenteritis across all ages. However, there is no effective or efficient treatment/control against norovirus infection. Conventional intervention techniques used to inactivate norovirus have shown lack of efficacy against human norovirus. Currently, effective treatment or control measures against human norovirus have not been identified. In this study, murine norovirus acts as a model to human norovirus to evaluate the inhibitory effects of crude extracts of Zanthoxylum armatum and Hibiscus sabdariffa. The study also separated, identified and quantified the selected compounds using the ultra-liquid chromatography (UPLC). To study the antiviral activities of crude extracts and its fractionated portions of Z. armatum and H. sabdariffa against norovirus surrogate, RAW 264.7 cells were infected with Murine norovirus surrogate virus of human norovirus and incubated at 37?C. Phytochemicals were extracted from the seeds and calyces of the plants using methanolic extraction. Fractionated portions of the crude extracts were subsequently used in both chromatographic and microbiological studies. Our data indicated that there was reduction of viruses, when treated with the 60% aqueous methanol extracts. Amongst the four selected phenolic compounds (myricetin, quercetin, kaempferol and luteolin), quercetin showed the most significant logarithmic viral reductions. These compounds were identified, purified and quantified using UPLC. Extracts of Zanthoxylum armatum and Hibiscus sabdariffa showed antiviral effects. Phenolic compounds are virucidal. Extracts of Hibiscus sabdariffa also exhibits anti-norovirus activities. The results are anticipated to control/prevent the human norovirus infections.
基金supported by the International Research Group Project (No. IRG-14-02) from the Deanship of Scientific Research at King Saud University, Saudi Arabia
文摘In most arid and semiarid soils, naturally occurring phosphorus(P) is a major yield-limiting plant nutrient. In this study, to investigate the effects of organic(OP) and inorganic P(IP) sources on P fractionation, a calcareous sandy loam alkaline soil was fertilized with OP and IP fertilizers at low(80 mg P kg^(-1) soil) and high(160 mg P kg^(-1) soil) application rates. Three combinations of OP and IP(i.e., 75% OP + 25% IP, 50% OP + 50% IP, and 25% OP + 75% IP) were applied at low and high application rates,respectively, followed by soil aging for 21 d. Soil samples were collected after 1, 2, 3, 7, and 21 d and subjected to sequential extraction to analyze soluble and exchangeable, Fe-and Al-bound, Ca-bound, and residual P fractions. The soluble and exchangeable P fraction significantly increased up to 24.3%, whereas the Ca-bound fraction decreased up to 40.7% in the soils receiving 75% OP + 25% IP and 50% OP + 50% IP, respectively, compared with the control(receiving no P fertilizer). However, the transformation of P fractions was influenced by aging time. Addition of P sources caused instant changes in different P fractions, which then tended to decline with aging time. Change in soil p H was the limiting factor in controlling P availability. At high application rate, the OP source significantly increased soil P availability compared with the IP source with soil aging. Depending on P fractionation, a proper combination of OP and IP fertilizers, as long-term slow and instant P-releasing sources for plant uptake, respectively, may be a sustainable strategy to meet crop P requirements in the arid and semiarid soils.
文摘Aqueous extracts from various plant parts of fenugreek(3%)(aerial parts:leaves and stems(LS),roots(R),ground seeds(GS)and not ground seeds(NGS))and petroleum ether,ethyl acetate and methanolic fractions of the aerial parts were assayed to determine their antifungal potential against Botrytis cinerea,Fusarium graminearum,Alternaria sp.,Pythium aphanidermatum,and Rhizoctinia solani.All fenugreek plant parts showed antifungal potential and the magnitude of their inhibitory effects was species and plant parts d...
文摘In urban waste (the first matter of compost), elements such as copper, nickel and lead may be found in metallic state (wire, pile, accumulator, etc.), which is considered as non-dependent state. The work undertaken at the laboratory of composting of the INRST in Henchir Lihoudia (Tunis) showed that the produced compost does not contain any mobile metallic element and the portion related to organic fraction (bioavailable) is tiny in size. We supposed that many reactions involving decomposition and complexation from elements related to the matrix components occurred during composting. The existence and importance of this phenomenon can be evaluated by studying the evolution of metal contents in the different fractions extracted sequentially during composting process.
文摘Grape pomace is the main by-product of wine production that concentrates bioactive metabolites of polyphenolic nature with antibacterial activity. Since grape pomace composition varied depending on grape variety, climate, vineyard location, and winemaking technology, it is important to study the composition and antibacterial activity of each variety separately. In this study, antibacterial activity against different food pathogens was evaluated and its relation with polyphenols content was determined. Grape pomace from Cabernet Sauvignon and Syrah varieties was extracted with methanol/HCl 1% (v/v), followed by sequential extractions with hexane, chloroform and ethyl acetate. Ethyl acetate fraction had the highest antibacterial activity determined through the microdilution method, reaching over 90% of inhibition at 500 μg·ml-1 with the exception of Salmonella Typhi (70% of inhibition). Staphylococcus aureus and Escherichia coli were the most susceptible strains, exceeding 50% of inhibition at 62.5 μg·ml-1. Ethyl acetate fraction contains the highest phenolic concentration in both Cabernet Sauvignon (132.2 mg of GAE g-1) and Syrah (102.6 mg of GAE g-1) pomace, as determined by the Folin-Ciocalteau method. Antibacterial activity present in grape pomace extracts is in direct relation to the polar phenolic content, in particular that from Cabernet Sauvignon.
基金supported by the National Natural Science Foundation of China (Nos.61571096,61775030,41274127,41301460,and 40874066)
文摘Most image saliency detection models are dependent on prior knowledge and demand high computational cost. However, spectral residual（SR） and phase spectrum of the Fourier transform（PFT） models are simple and fast saliency detection approaches based on two-dimensional Fourier transform without the prior knowledge. For seismic data, the geological structure of the underground rock formation changes more obviously in the time direction. Therefore, one-dimensional Fourier transform is more suitable for seismic saliency detection. Fractional Fourier transform（FrFT） is an improved algorithm for Fourier transform, therefore we propose the seismic SR and PFT models in one-dimensional FrF T domain to obtain more detailed saliency maps. These two models use the amplitude and phase information in FrFT domain to construct the corresponding saliency maps in spatial domain. By means of these two models, several saliency maps at different fractional orders can be obtained for seismic attribute analysis. These saliency maps can characterize the detailed features and highlight the object areas, which is more conducive to determine the location of reservoirs. The performance of the proposed method is assessed on both simulated and real seismic data. The results indicate that our method is effective and convenient for seismic attribute extraction with good noise immunity.
