[Objectives]The soil permeability and its influencing factors in typical plantations were studied to provide a scientific basis for tending and managing plantations in the Haikou forest area of Kunming City.[Methods]W...[Objectives]The soil permeability and its influencing factors in typical plantations were studied to provide a scientific basis for tending and managing plantations in the Haikou forest area of Kunming City.[Methods]With three kinds of typical forest stands,i.e.,over-mature Pinus armandii Franch.,mid-mature Eucalyptus robusta Smith,and over-mature E.robusta Smith in this region as the research objects,soil infiltration changes and the effects on soil water retention in different stands,soil layers,and gap conditions under different moisture conditions were analyzed.[Results]①Under all three moisture conditions,the over-mature P.armandii forest demonstrated higher overall infiltration rates than the other two forest stands,which showed relatively similar infiltration rates.In all three stands,the soil infiltration rate decreased as the depth of the soil increased.Significant fluctuations in soil infiltration rate were observed during the initial 0-5 min,followed by gradual stabilization or regular fluctuations after 5 min.The infiltration process generally reached saturation after approximately 20 min.②The average infiltration rate was identified as the key factor affecting soil infiltration.Comprehensive evaluation of soil permeability revealed that the over-mature P.armandii forest exhibited optimal soil permeability.③Various soil physical and chemical properties significantly affected different indexes of soil permeability under varying conditions,with soil organic carbon content and water repellency demonstrating particularly notable effects on infiltration under different conditions.[Conclusions]Soil infiltration rates gradually decreased with the deepening of the soil layer.Principal component analysis(PCA)showed that the soil permeability of the over-mature P.armandii forest was stronger than that of the other two stands under the three moisture conditions,especially in non-gap positions.All soil indexes affected soil permeability,and soil organic carbon and water repellency were the key factors affecting soil permeability.展开更多
This study demonstrated that the variation in physical and chemical performance on cotton double jersey knit fabrics was decided by the knit structure, water repellent chemicals types and their concentration. Here, tw...This study demonstrated that the variation in physical and chemical performance on cotton double jersey knit fabrics was decided by the knit structure, water repellent chemicals types and their concentration. Here, two types of double jersey fabrics were treated with different types of water repellent chemicals at different formulations to evaluate the performance of water repellent finishes on knit fabrics properties. The levels of water repellency of the fabrics were assessed by AATCC 127 hydrostatic head test method and by ISO 4920:2012 spray rating test method. To evaluate the performance of water repellent finishes on knit fabric properties, GSM, bursting strength test according to ASTM (D 3786-87) method, air permeability, color fastness to wash, water, perspiration, chlorinated water and color fastness to rubbing with ISO method were done. The results showed that both physical and chemical properties of the finished cotton knits, depend to a great extent on knit structure, the water repellent finish type and concentration to obtain water repellent fabrics with desirable properties.展开更多
Objective:To determine the ovicidal and repellent activities of methanol leaf extract of Ervatamia coronaria(E.coronaria) and Caeslpinia pulckerrima(C.pulcherrima) against Culex quinquefasciatus(Cx.quinquefasciatus),A...Objective:To determine the ovicidal and repellent activities of methanol leaf extract of Ervatamia coronaria(E.coronaria) and Caeslpinia pulckerrima(C.pulcherrima) against Culex quinquefasciatus(Cx.quinquefasciatus),Aedes aegypti(Ae.aegypti) and Anopheles stephensi(An. stephensi).Methods:The ovicidal activity was determined against three mosquito species at various concentrations ranging from 50-450 ppm under the laboratory conditions.The hatch rates were assessed 48 h after treatment.The repellent efficacy was determined against three mosquito species at three concentrations viz.,1.0,2.5 and 5.0 mg/cm under the laboratory conditions. Results:The crude extract of E.coronaria exerted zero hatchability(100%mortality) at 250.200 and 150 ppm for Cx.quinqitefasciatus,Ae.aegypti and An.stephensi,respectively.The crude extract of C.pulchenima exerted zero hatchability(100%mortality) at 375.300 and 225 ppm for Cx.quinquefasciatus,Ae.aegypti and An.Stephensi,respectively.The methanol extract of E. coronaria found to be more repellenct than C.pukherrima extract.A higher concentration of 5.0 mg/cm^2 provided 100%protection up to 150.180 and 210 min against Cx.quinquefasciatus,Ae. aegypti and An.stephensi,respectively.The results clearly showed that repellent activity was dose dependent.Conclusions:From the results it can be concluded the crude extracts of E.coronaria and C.pukherrima are an excellent potential for controlling Cx.quinquefasciatus,Ae.aegypti and An.stephensi mosquitoes.展开更多
Objective:To determine the larvicidal and repellent activities of Sida acuta Burm.F.（Family: Malvaceae）extract against Culex quinquefasciatus,Aedes aegypti and Anopheles stephensi. Methods:Twenty five late III insta...Objective:To determine the larvicidal and repellent activities of Sida acuta Burm.F.（Family: Malvaceae）extract against Culex quinquefasciatus,Aedes aegypti and Anopheles stephensi. Methods:Twenty five late III instar larve of three mosquito species were exposed to various concentrations（15-90 mg/L） and were assayed in the laboratory by using the protocol of WHO 2005:the 24 h LC<sub>50</sub> values of the Sida acuta leaf extract was determined following Probit analysis. The repellent efficacy was determined against three mosquito species at three concentrations viz.,1.0,2.5 and 5.0 mg/cm<sup>2</sup> under the laboratory conditions.Results:Results showed varying degree of larvicidal activity of crude extract of Sida acuta against three important mosquitoes with LC<sub>50</sub> values ranging between 38 to 48 mg/L.The crude extract had strong repellent action against three species of mosquitoes as it provided 100%protection against Anopheles stephensi for 180 min followed by Aedes aegypti（150 min） and Culex quinquefasciatus（120 min）.Conclusions: From the results it can be concluded the crude extract of Sida acuta was an excellent potential for controlling Culex quinquefasciatus,Aedes aegypti and Anopleles stephensi mosquitoes.展开更多
Objective:To evaluate the larvicidal and repellent activities of ethyl acetate and methanol extracts of Acacia concinna（A.concinna）,Cassia siamea（C.siamea）.Conundrum sativum（C. sativum）,Cuminum cyminum（C.cyminu...Objective:To evaluate the larvicidal and repellent activities of ethyl acetate and methanol extracts of Acacia concinna（A.concinna）,Cassia siamea（C.siamea）.Conundrum sativum（C. sativum）,Cuminum cyminum（C.cyminum）,Lantana camma（L.camara）,Nelumbo nucifera （N.nucifera） Phyllanlhus amarus（P.amarus）.Piper nigrum（P.nigrum） and Trachyspermum ammi（T.ammi） against Anopheles stephensi（An.stephensi） and Culex quinquefasciatus（Cx. quinquefasciatus）.Methods:The larvicidal activity of medicinal plant extracts were tested against earl) fourth-instar larvae of malaria and filariasis vectors.The mortality was observed 24 h and 48 h after treatment,data were subjected to probit analysis to determine the lethal concentrations(LC<sub>50</sub> and LC<sub>90</sub>) to kill 50 and 90 per cent of the treated larvae of the tested species. The repellent efficacy was determined against two mosquito species at five concentrations（31.25. 62.50.125.00.250.00,and 500.00 ppm） under the laboratory conditions.Results:All plant extracts showed moderate effects after 24 h and 48 h of exposure;however,the highest activity was observed after 24 h in the leaf methanol extract ol N.nucifera.seed ethyl acetate and methanol extract of P.nigrum against the larvae of An.Stephensi(LC<sub>50</sub> = 34.76.24.54 and 30.20 ppm) and against Cx.quinquefasciatus(LC<sub>50</sub>= 37.49.43.94 and 57.39 ppm),respectively.The toxic effect of leaf methanol extract of C.siamea,seed methanol extract of C.cyminum,leaf ethyl acetate extract of N.nucifera.leaf ethyl acetate and methanol extract of P.amarus and seed methanol extract of T.ammi were showed 100%mortality against An.stephensi and Cx.quinquefasciatus alter 48 h exposer.The maximum repellent activity was observed at 500 ppm in methanol extracts of N. nucifera.ethyl acetate and methanol extract of P.nigrum and methanol extract of T.ammi and the mean complete protection time ranged from 30 to 150 min with the different extracts tested. Conclusions:These results suggest that the leaf and seed extracts of C.siamea.N.nucifera.P. amarus.P.nigrum and T.ammi have the potential to be used as an ideal ecofriendly approach for the control of the An.stephensi and Cx.quinquefasciatus.展开更多
Objective:To investigate the larvicidal and repellent properties of essential oils from various parts of four plant species Cymbopogan citrates,Cinnamomum zeylanicum,Rosmarinus of ficinalis and Zingiber of ficinale ag...Objective:To investigate the larvicidal and repellent properties of essential oils from various parts of four plant species Cymbopogan citrates,Cinnamomum zeylanicum,Rosmarinus of ficinalis and Zingiber of ficinale against Culex tritaeniorhynchus（Cx.tritaeniorhynchus） and Anopheles subpictus（An.subpktus）.Methods:Essential oils were obtained by hydro-distillation method.The mosquitoes were reared in the vector control laboratory and twenty five late third ins tar larvae of Cx.tritaeniorhynchus and An.subpictus were exposed to based on the wide range and narrow range test,essential oil tested at various concentrations ranging from 25 to 250 ppm.The larval mortality was observed after 24 h under the laboratory conditions.The repellent efficacy was determined against two mosquito species at three concentrations viz., 1.0,2.5 and 5.0 mg/cm<sup>2</sup> under laboratory conditions.Results:Results showed all the four plant essential oil produced significant larval mortality against two mosquito species.However,the highest larvicidal activity was observed in the essential oil from Zingiber of ficinale against Cx. tritaeniorhynchus and An.subpktus with the LC<sub>50</sub> and LC<sub>90</sub> values as 98.83,57.98 ppm and 186.55, 104.23 ppm,respectively.All the four essential oil shows significant repellency against Cx. tritaeniorhynchus than An.subpktus.Among four essential oil tested the highest repellency was observed in Zingiber of ficinale,a higher concentration of 5.0 mg/cm<sup>2</sup> provided 100%protection up to 150 and 180 min against Cx.tritaeniorhynchus and An.subpktus,respectively.Conclusions: In this work,it can be concluded that four essential oils which were distilled from Cymbopogan citrates,Cinnamomum zeylanicum,Rosmarinus of ficinalis and Zingiber of ficinale showed promising larvicidal and repellent agent against Cx.tritaeniorhynchus and An.subpktus.展开更多
ObjectiveTo determine the adulticidal and repellent activities of different solvent leaf extracts of Eclipta alba (E. alba) and Andrographis paniculata (A. paniculata) against malarial vector, Anopheles stephensi (An....ObjectiveTo determine the adulticidal and repellent activities of different solvent leaf extracts of Eclipta alba (E. alba) and Andrographis paniculata (A. paniculata) against malarial vector, Anopheles stephensi (An. stephensi).MethodsAdulticidal efficacy of the crude leaf extracts of E. alba and A. paniculata with five different solvents like benzene, hexane, ethyl acetate, methanol and chloroform was tested against the five to six day old adult female mosquitoes of An. stephensi. The adult mortality was observed after 24 h under the laboratory conditions. The repellent efficacy was determined against An. stephensi mosquito species at three concentrations viz., 1.0, 2.5 and 5.0 mg/cm2 under laboratory conditions.ResultsAmong the tested solvents the maximum efficacy was observed in the methanol extract. The LC50 and LC90 values of E. alba and A. paniculata against adults of An. stephensi were 150.36, 130.19 ppm and 285.22, 244.16 ppm, respectively. No mortality was observed in controls. The chi-square values were significant at P<0.05 level. Methanol extract of E. alba and A. paniculata was produce maximum repellency against An. stephensi.ConclusionsFrom the results it can be concluded the crude extract of E. alba and A. paniculata was an excellent potential for controlling An. stephensi mosquitoes.展开更多
Objective:To test fumigant and repellent properties of sesquiterpene—rich essential oil from Teucrium polium subsp.capitation(L.).Methods:The fumigant toxicity test was performed at(27±1)℃.(65± 5)%relative...Objective:To test fumigant and repellent properties of sesquiterpene—rich essential oil from Teucrium polium subsp.capitation(L.).Methods:The fumigant toxicity test was performed at(27±1)℃.(65± 5)%relative humidity,and under darkness condition and 24 h exposure time.The chemical composition of the isolated oils was examined by gas chromatography—mass spectrometry.Results:The major compounds were α-cadiuol(46.2%),earyophyllene oxide(25.9%),α muurolol epi(8.1%),cadalene(3.7%) and longiverbenone(2.9%).In all cases,considerable differences in mortality of insect to essential oil vapor were observed in different concentrations and exposure times.Callosobruchus maculatus(C.maculates)(LC_(50)=148.9μL/L air) was more susceptible to the tested plant product than Teucrium castaneum(T.castaneum)(LC_(50)=360.2μL/L ain based on LC_(50)values.In the present investigation,the concentration of 3μ L /mL acetone showed 60% and 52% repellency against T.casteneum and C.maculatus adults,respectively.Conclusions:The results suggests that sesquiterpene—rich essential oils from the tested plant could be used as a potential control agent for stored—product insects.展开更多
Objective:To formulate nanoemulsion from essential oils of Mentha(M.)piperita L.and Eucalyptus(E.)globulus L.and to compare their repellant activity with normal essential oils and N,N-diethyl-m toluamide(DEET)as a sta...Objective:To formulate nanoemulsion from essential oils of Mentha(M.)piperita L.and Eucalyptus(E.)globulus L.and to compare their repellant activity with normal essential oils and N,N-diethyl-m toluamide(DEET)as a standard chemical compound.Methods:In this study,protection time of essential oils and DEET was evaluated on four human subjects using test cage,and their values were determined against Anopheles stephensi.Furthermore,ED50 values for the above essential oils were determined using the ASTM E951-94 method.The compositions of essential oils were determined using GC-MS,and droplet size and zeta potential of the nanoemulsion were measured with dynamic light scattering.Results:The results(expressed as mean±SD)showed that protection time of M.piperita 50%,M.piperita Nano 50%,E.globulus 50%,E.globulus Nano 50%,and DEET 25%was(2.89±0.45)h,(4.17±0.28)h,(0.96±0.27)h,(5.51±0.02)h,and(6.10±0.47)h,respectively.ED50 values were 29.10(95%CI:23.36-36.06)μg/cm^2 for Mentha,19.39(15.35-23.99)μg/cm^2 for Mentha Nano,36.10(28.70-48.01)μg/cm^2 for Eucalyptus,18.50(14.65-23.23)μg/cm^2 for Eucalyptus Nano,and 3.62(2.68-4.55)μg/cm^2 for DEET,respectively.E.globulus Nano and M.piperita Nano provided significantly longer protection than normal essential oils E.globulus and M.piperita(P<0.01).Conclusions:The preparation of nanoemulsion from the essential oils of M.piperita and E.globulus,significantly increases the protection time and reduces ED50 values of these essential oils,hence,M.piperita Nano and E.globulus Nano can be good alternatives to DEET and other chemical compounds.展开更多
This paper introduces an effective anti-icing strategy that uses passive anti-icing property and active de-icing functions concurrently.These dual capabilities can alleviate the icing problem more effectively than eit...This paper introduces an effective anti-icing strategy that uses passive anti-icing property and active de-icing functions concurrently.These dual capabilities can alleviate the icing problem more effectively than either a passive or active function alone.The developed material is a slippery liquid-repellent elastic conductor(SLEC);it is an organogel that is composed of multi-walled carbon nanotubes,oil,and polydimethylsiloxane.The SLEC maintains passive water-droplet sliding ability even on wet surfaces that frequently occur in cold conditions(e.g.,during condensation and defrosting),suppresses ice nucleation,and shows ice adhesion strength as low as^20 kPa.The SLEC releases heat when it is subject to electrical or photonic stimulation,and can therefore it can prevent ice formation and melt ice that has already formed on a surface.This material has sustainable liquid repellence by syneresis and replenishment;this ability ensures long-lasting anti-icing property,and results in exceptional durability.This durability is stable against mechanical damage.The superior dual anti-icing capabilities together with the sustainable and stable liquid repellence should generate synergistic effects,and yield a powerful anti-icing tool that can broaden the range of icing applications.展开更多
Six species of wild rice with different ecophenotypes including Oryza grandiglumis （E6-1, E6-3 / 6-4）, O. minuta （E13-9, E13-13）, O. officinalis（E15-8, E15-13）, O. punctata （E16-1, E16-3, E16-13）, O. granulata...Six species of wild rice with different ecophenotypes including Oryza grandiglumis （E6-1, E6-3 / 6-4）, O. minuta （E13-9, E13-13）, O. officinalis（E15-8, E15-13）, O. punctata （E16-1, E16-3, E16-13）, O. granulata（E7-4）, and O. latifolia（101392, E9-1, E9-10） were extracted with methnol and the repellent activity of the extracts against the two insects Aphis citricola and Panonychus citri were studied. The extracts of O. officinalis E15-8 showed higher repellent rate to the two insects than those of the other species. The repellent rates of the extracts of E15-8 to P. citriand A. citricola were 83.26% and 87.86% at 5×10^4 μg/mL in 24 h and 87.95% and 82.43% in 48 h, respectively. The extracts of O. officinalis E15-8 had the effect of inhibition to the esterase of the two insects.展开更多
Soil water repellency （SWR） is one of the most important physical properties of soils found all over the world, and it may have significant effects on the eco-hydrological processes of land ecosystems. In this study...Soil water repellency （SWR） is one of the most important physical properties of soils found all over the world, and it may have significant effects on the eco-hydrological processes of land ecosystems. In this study, the Capillary Rise Method was used to measure the SWR in the artificial vegetation area in Shapotou, located in the southeast area of the Tengger Desert, Ningxia Prov- ince of western China. The variation of the soil water repellency among different minor topographies, different depths and differ- ent particle sizes was analyzed. The results of the study indicate that the SWR shows distinct changes with vegetation restoration, and it increases with an increase in the period of dune stabilization. In the same vegetation area, the SWR of soils in inter-dune depressions or windward slopes is slightly greater than that in crest or leeward slopes. The SWR of 0-3 cm topsoil is significantly greater than that in the 3-6 cm soil layer. The SWR decreases with an increase in grain size and the differences among the SWRs of different sieved soil fractions are found to be significant. There is also a significantly positive correlation between the SWR and the proportion of soils with grain sizes of 0-0.05, 0.05-0.01 and 0.01-0.15 mm, and a significantly negative correlation between the SWR and the propotion of soils with grain sizes exceeding 0.15 mm. The increase of SWR in revegetation areas may depend on the continuous depositing of atmospheric dust on the stabilized dune surface as well as the formation of biological soil crusts, especially on the formation of algal and lichen crusts. Enhanced SWR influences the effectiveness of water use of sand plants in- habiting the sand dunes.展开更多
Highlight Semaphorin 3A is a classically known axonal guidance cue that mediates axonal growth cone repulsion and collapse.Recent works,however,suggest that it may have the apparently diametrically opposite activity o...Highlight Semaphorin 3A is a classically known axonal guidance cue that mediates axonal growth cone repulsion and collapse.Recent works,however,suggest that it may have the apparently diametrically opposite activity of promoting neuronal regeneration.展开更多
Objective:To determine repellent activity of hexane,ethyl acetate,benzene,chloroform and methanol extract of Cardiospermum halicacabum,(C.halicacabum) against Culex quinque/ascialus(Cx.quinquefuscialus),Aedes aegypti(...Objective:To determine repellent activity of hexane,ethyl acetate,benzene,chloroform and methanol extract of Cardiospermum halicacabum,(C.halicacabum) against Culex quinque/ascialus(Cx.quinquefuscialus),Aedes aegypti(Ae.aegypli) and Anopheles slephensi(An.slephensi). Methods:Evaluation was carried out in a net cage(45 cm×30 cm×25 cm) containing 100 blood starved female mosquitoes of three mosquito species and were assayed in the laboratory condition by using the protocol of WHO 2005;The plant leaf crude extracts of C.halicacabum was applied at 1.0,2.5,and 5.0 me/cm^2 separately in the exposed area of the fore arm.Only ethanol served as control.Results:In this observation,the plant crude extracts gave protection against mosquito bites without any allergic reaction to the test person,and also,the repellent activity was dependent on the strength of the plant extracts.The tested plant crude extracts had exerted promising repellent against all the three mosquitoes.Conclusions:From the results it can be concluded the crude extract of C.halicacabum was potential for controlling Cx.quinquefasciatus, Ae.aegypli and An.slephensi mosquitoes.展开更多
Objective:To investigate the larvicidal and repellent efficacy of tetradecanoic acid against Aedes aegrpti（Ae.aegypti） L,and Culex quinquefasciatus（Cx.quinquefasciatus） Say（Diptera: Culicidae）.Methods:Larvicidal...Objective:To investigate the larvicidal and repellent efficacy of tetradecanoic acid against Aedes aegrpti（Ae.aegypti） L,and Culex quinquefasciatus（Cx.quinquefasciatus） Say（Diptera: Culicidae）.Methods:Larvicidal efficacy of tetradecanoic acid was tested at various concentrations against the early third instar larvae of Ae.aegypti and Cx.quinquefasciatus. The repellent activity was determined against two mosquito species at three concentrations viz..1.0.2.5 and 5.0 ppm under the laboratory conditions.Results:The tetradecanoic acid was found to be more effective against Cx.quinquefasciatus than Ae.aegypti larvae.The LC<sub>50</sub> values were 14.08 ppm and 25.10 ppm,respectively.Tetradecanoic acid showed lesser repellency against Ae.aegypti and Cx.quinquefasciatus.The highest repellency was observed in higher concentration of 5.0 mg/cm<sup>2</sup> provided 100%protection up to 60 and 90 min against Ae.aegypti and Cx.quinquefasciatus respectively.Conclusions:From the results it can be concluded the tetradecanoic acid is a potential for controlling Cx.quinquefasciatus and Ae.aegypti mosquitoes.展开更多
Water-repellent(WR) soil greatly influences infiltration behavior. This research determined the impacts of WR levels of silt loam soil layer during infiltration. Three column scenarios were utilized, including homogen...Water-repellent(WR) soil greatly influences infiltration behavior. This research determined the impacts of WR levels of silt loam soil layer during infiltration. Three column scenarios were utilized, including homogeneous wettable silt loam or sand, silt loam over sand(silt loam/sand), and sand over silt loam(sand/silt loam). A 5-cm thick silt loam soil layer was placed either at the soil surface or 5 cm below the soil surface. The silt loam soil used had been treated to produce different WR levels, wettable, slightly WR, strongly WR, and severely WR. As the WR level increased from wettable to severely WR, the cumulative infiltration decreased. Traditional wetting front-related equations did not adequately describe the infiltration rate and time relationships for layered WR soils. The Kostiakov equation provided a good fit for the first infiltration stage. Average infiltration rates for wettable, slightly WR, strongly WR, and severely WR during the 2 nd infiltration stage were 0.126, 0.021, 0.002, and 0.001 mm min^(-1) for the silt loam/sand scenario,respectively, and 0.112, 0.003, 0.002, and 0.000 5 mm min^(-1) for the sand/silt loam scenario, respectively. Pseudo-saturation phenomena occurred when visually examining the wetting fronts and from the apparent changes in water content(?θ_(AP)) at the slightly WR,strongly WR, and severely WR levels for the silt loam/sand scenario. Much larger ?θAPvalues indicated the possible existence of finger flow. Delayed water penetration into the surface soil for the strongly WR level in the silt loam/sand scenario suggested negative water heads with infiltration times longer than 10 min. The silt loam/sand soil layers produced sharp transition zones of water content. The WR level of the silt loam soil layer had greater effects on infiltration than the layer position in the column.展开更多
Zingiber cassumunar is an important plant used in traditional medicine and as a natural mosquito re-pellent.However,the compounds responsible for the repellent activity of the plant are still unknown.The aim of the st...Zingiber cassumunar is an important plant used in traditional medicine and as a natural mosquito re-pellent.However,the compounds responsible for the repellent activity of the plant are still unknown.The aim of the study is to identify the components of Z.cassumunar essential oil that show repellent activity against Aedes albopictus.We also evaluated the larvicidal and adulticidal activities of Z.cassumunar essential oil against Ae.albopictus.In-cage mosquito repellent experiments showed that Z.cassumunar essential oil possessed moderate repellent activity with a minimum effective dose(MED)of 0.16±0.01 mg/cm^(20,compared to reference standard N,N-diethyl-3-methylbenzamide(DEET,0.03±0.01 mg/cm^(20).Bioassay-guided fractionation identified the major active compound of Z.cassumunar essential oil as(-)-terpinen-4-ol(1)(MED:0.19±0 mg/cm^(20).We also found that Z.cassumunar essential oil showed moderate larvicidal activity against first instar larvae of Ae.albopictus with a LC50(50%lethal concentration)of 44.9 mg/L after 24 h.Fumigation bioassays showed that Z.cassumunar essential oil exhibits moderate adulticidal activity against Ae.albopictus with a LC50 of 5.44%,while(-)-terpinen-4-ol showed significant adulticidal activity with a LC50 of 2.10%after 24 h.This study verifies that the Z.cassumunar essential oil has mosquito repellent activity,and that(-)-terpinen-4-ol is mainly responsible for this activity.Furthermore,this study provides scientific support for the folk usage of Z.cassumunar essential oil as mosquito repellent and indicates that Z.cassumunar essential oil and(-)-terpinen-4-ol can be used as plant-derived repellents and insecticides for mosquito control.展开更多
Soil wettability and water repellency, two important soil physical properties, play an important role in water retention and water conductivity in arid and semi-arid regions. To date, there is a lack of information on...Soil wettability and water repellency, two important soil physical properties, play an important role in water retention and water conductivity in arid and semi-arid regions. To date, there is a lack of information on soil water repellency in calcareous soils of western lran. In this study, soil water repellency and its affecting factors were studied using 20 soil series collected from Hamadan Province~ western Iran. The effects of soil properties including organic carbon content （SOC）, total nitrogen （TN）, C：N ratio, texture, CaCO3 content, and both fungal and bacterial activities on water repellency were investigated using air-dried, oven-dried and heated soil samples. Water repellency index （WRI） was determined using the short-time sorptivity （water/ethanol） method. To distinguish the actual effects of SOC, a set of soil samples were heated at 300 ~C to remove SOC and then WRI was measured on the heated samples. Relative water repellency index （RWRI） was defined as the change of WRI due to heating relative to the oven-dry WRI value. Results of the WRI values showed that the soils were sub-critically water-repellent. Pasture soils had higher WRI values compared to tilled soils, resulting from high SOC and TN, and high activities of bacteria and fungi. It was observed that SOC, TN, fungal activity, and SOC：clay ratio had significant positive impacts on WRI. Strong positive correlations of RWRI with SOC, TN and fungal activity were also observed. Pedotransfer functions derived for predicting WRI showed that the WRI values had an increasing trend with the increases in fungal activity, salinity, alkalinity and fine clay content, but showed a decreasing trend with increasing bacterial activity.展开更多
Long lasting insect repellent curtain fabrics were developed and characterized. Different types of fabrics which are generally used in manufacture of curtain fabrics were functionalized with monochlorotriazenyl β-cyc...Long lasting insect repellent curtain fabrics were developed and characterized. Different types of fabrics which are generally used in manufacture of curtain fabrics were functionalized with monochlorotriazenyl β-cyclodextrin (MCT-β-CD) then treated with different concentration from permethrin to impart the fabric insect repellent properties. These fabrics were 100% cotton, cotton/viscose, cotton/linen, polyester/cotton, polyester/linen and polyester/viscose blend fabrics. The treated curtain fabrics were evaluated for insect repellent retention capacity against mosquitoes. The repellent efficacy comprises the determination of percent mosquitoes repelled, knockdown and killed (mortality) resulting from exposed mosquitoes to the treated fabric. Results obtained shows that, the insect repellent retention capacity of curtain fabrics functionalized with R-β-CD then treated with permethrin depends on the amount of β-CD moieties on the curtain fabrics, type of fabric and permethrin concentration. Higher action is obtained when the fabric was functionalized with 100 g/L, MCT-β-CD in alkaline medium followed by treatment with 15 g/L permethrin. The results show also that, curtain fabric made of cotton/linen shows highest mosquitoes repellent retention capacity and highest resistance against washing compared with 100% cotton or cotton/viscose or polyester based curtain fabrics. The insect repellent treatment of curtain fabrics did not adversely affect the tensile strength or drapability index of curtain展开更多
文摘[Objectives]The soil permeability and its influencing factors in typical plantations were studied to provide a scientific basis for tending and managing plantations in the Haikou forest area of Kunming City.[Methods]With three kinds of typical forest stands,i.e.,over-mature Pinus armandii Franch.,mid-mature Eucalyptus robusta Smith,and over-mature E.robusta Smith in this region as the research objects,soil infiltration changes and the effects on soil water retention in different stands,soil layers,and gap conditions under different moisture conditions were analyzed.[Results]①Under all three moisture conditions,the over-mature P.armandii forest demonstrated higher overall infiltration rates than the other two forest stands,which showed relatively similar infiltration rates.In all three stands,the soil infiltration rate decreased as the depth of the soil increased.Significant fluctuations in soil infiltration rate were observed during the initial 0-5 min,followed by gradual stabilization or regular fluctuations after 5 min.The infiltration process generally reached saturation after approximately 20 min.②The average infiltration rate was identified as the key factor affecting soil infiltration.Comprehensive evaluation of soil permeability revealed that the over-mature P.armandii forest exhibited optimal soil permeability.③Various soil physical and chemical properties significantly affected different indexes of soil permeability under varying conditions,with soil organic carbon content and water repellency demonstrating particularly notable effects on infiltration under different conditions.[Conclusions]Soil infiltration rates gradually decreased with the deepening of the soil layer.Principal component analysis(PCA)showed that the soil permeability of the over-mature P.armandii forest was stronger than that of the other two stands under the three moisture conditions,especially in non-gap positions.All soil indexes affected soil permeability,and soil organic carbon and water repellency were the key factors affecting soil permeability.
文摘This study demonstrated that the variation in physical and chemical performance on cotton double jersey knit fabrics was decided by the knit structure, water repellent chemicals types and their concentration. Here, two types of double jersey fabrics were treated with different types of water repellent chemicals at different formulations to evaluate the performance of water repellent finishes on knit fabrics properties. The levels of water repellency of the fabrics were assessed by AATCC 127 hydrostatic head test method and by ISO 4920:2012 spray rating test method. To evaluate the performance of water repellent finishes on knit fabric properties, GSM, bursting strength test according to ASTM (D 3786-87) method, air permeability, color fastness to wash, water, perspiration, chlorinated water and color fastness to rubbing with ISO method were done. The results showed that both physical and chemical properties of the finished cotton knits, depend to a great extent on knit structure, the water repellent finish type and concentration to obtain water repellent fabrics with desirable properties.
文摘Objective:To determine the ovicidal and repellent activities of methanol leaf extract of Ervatamia coronaria(E.coronaria) and Caeslpinia pulckerrima(C.pulcherrima) against Culex quinquefasciatus(Cx.quinquefasciatus),Aedes aegypti(Ae.aegypti) and Anopheles stephensi(An. stephensi).Methods:The ovicidal activity was determined against three mosquito species at various concentrations ranging from 50-450 ppm under the laboratory conditions.The hatch rates were assessed 48 h after treatment.The repellent efficacy was determined against three mosquito species at three concentrations viz.,1.0,2.5 and 5.0 mg/cm under the laboratory conditions. Results:The crude extract of E.coronaria exerted zero hatchability(100%mortality) at 250.200 and 150 ppm for Cx.quinqitefasciatus,Ae.aegypti and An.stephensi,respectively.The crude extract of C.pulchenima exerted zero hatchability(100%mortality) at 375.300 and 225 ppm for Cx.quinquefasciatus,Ae.aegypti and An.Stephensi,respectively.The methanol extract of E. coronaria found to be more repellenct than C.pukherrima extract.A higher concentration of 5.0 mg/cm^2 provided 100%protection up to 150.180 and 210 min against Cx.quinquefasciatus,Ae. aegypti and An.stephensi,respectively.The results clearly showed that repellent activity was dose dependent.Conclusions:From the results it can be concluded the crude extracts of E.coronaria and C.pukherrima are an excellent potential for controlling Cx.quinquefasciatus,Ae.aegypti and An.stephensi mosquitoes.
文摘Objective:To determine the larvicidal and repellent activities of Sida acuta Burm.F.（Family: Malvaceae）extract against Culex quinquefasciatus,Aedes aegypti and Anopheles stephensi. Methods:Twenty five late III instar larve of three mosquito species were exposed to various concentrations（15-90 mg/L） and were assayed in the laboratory by using the protocol of WHO 2005:the 24 h LC<sub>50</sub> values of the Sida acuta leaf extract was determined following Probit analysis. The repellent efficacy was determined against three mosquito species at three concentrations viz.,1.0,2.5 and 5.0 mg/cm<sup>2</sup> under the laboratory conditions.Results:Results showed varying degree of larvicidal activity of crude extract of Sida acuta against three important mosquitoes with LC<sub>50</sub> values ranging between 38 to 48 mg/L.The crude extract had strong repellent action against three species of mosquitoes as it provided 100%protection against Anopheles stephensi for 180 min followed by Aedes aegypti（150 min） and Culex quinquefasciatus（120 min）.Conclusions: From the results it can be concluded the crude extract of Sida acuta was an excellent potential for controlling Culex quinquefasciatus,Aedes aegypti and Anopleles stephensi mosquitoes.
文摘Objective:To evaluate the larvicidal and repellent activities of ethyl acetate and methanol extracts of Acacia concinna（A.concinna）,Cassia siamea（C.siamea）.Conundrum sativum（C. sativum）,Cuminum cyminum（C.cyminum）,Lantana camma（L.camara）,Nelumbo nucifera （N.nucifera） Phyllanlhus amarus（P.amarus）.Piper nigrum（P.nigrum） and Trachyspermum ammi（T.ammi） against Anopheles stephensi（An.stephensi） and Culex quinquefasciatus（Cx. quinquefasciatus）.Methods:The larvicidal activity of medicinal plant extracts were tested against earl) fourth-instar larvae of malaria and filariasis vectors.The mortality was observed 24 h and 48 h after treatment,data were subjected to probit analysis to determine the lethal concentrations(LC<sub>50</sub> and LC<sub>90</sub>) to kill 50 and 90 per cent of the treated larvae of the tested species. The repellent efficacy was determined against two mosquito species at five concentrations（31.25. 62.50.125.00.250.00,and 500.00 ppm） under the laboratory conditions.Results:All plant extracts showed moderate effects after 24 h and 48 h of exposure;however,the highest activity was observed after 24 h in the leaf methanol extract ol N.nucifera.seed ethyl acetate and methanol extract of P.nigrum against the larvae of An.Stephensi(LC<sub>50</sub> = 34.76.24.54 and 30.20 ppm) and against Cx.quinquefasciatus(LC<sub>50</sub>= 37.49.43.94 and 57.39 ppm),respectively.The toxic effect of leaf methanol extract of C.siamea,seed methanol extract of C.cyminum,leaf ethyl acetate extract of N.nucifera.leaf ethyl acetate and methanol extract of P.amarus and seed methanol extract of T.ammi were showed 100%mortality against An.stephensi and Cx.quinquefasciatus alter 48 h exposer.The maximum repellent activity was observed at 500 ppm in methanol extracts of N. nucifera.ethyl acetate and methanol extract of P.nigrum and methanol extract of T.ammi and the mean complete protection time ranged from 30 to 150 min with the different extracts tested. Conclusions:These results suggest that the leaf and seed extracts of C.siamea.N.nucifera.P. amarus.P.nigrum and T.ammi have the potential to be used as an ideal ecofriendly approach for the control of the An.stephensi and Cx.quinquefasciatus.
文摘Objective:To investigate the larvicidal and repellent properties of essential oils from various parts of four plant species Cymbopogan citrates,Cinnamomum zeylanicum,Rosmarinus of ficinalis and Zingiber of ficinale against Culex tritaeniorhynchus（Cx.tritaeniorhynchus） and Anopheles subpictus（An.subpktus）.Methods:Essential oils were obtained by hydro-distillation method.The mosquitoes were reared in the vector control laboratory and twenty five late third ins tar larvae of Cx.tritaeniorhynchus and An.subpictus were exposed to based on the wide range and narrow range test,essential oil tested at various concentrations ranging from 25 to 250 ppm.The larval mortality was observed after 24 h under the laboratory conditions.The repellent efficacy was determined against two mosquito species at three concentrations viz., 1.0,2.5 and 5.0 mg/cm<sup>2</sup> under laboratory conditions.Results:Results showed all the four plant essential oil produced significant larval mortality against two mosquito species.However,the highest larvicidal activity was observed in the essential oil from Zingiber of ficinale against Cx. tritaeniorhynchus and An.subpktus with the LC<sub>50</sub> and LC<sub>90</sub> values as 98.83,57.98 ppm and 186.55, 104.23 ppm,respectively.All the four essential oil shows significant repellency against Cx. tritaeniorhynchus than An.subpktus.Among four essential oil tested the highest repellency was observed in Zingiber of ficinale,a higher concentration of 5.0 mg/cm<sup>2</sup> provided 100%protection up to 150 and 180 min against Cx.tritaeniorhynchus and An.subpktus,respectively.Conclusions: In this work,it can be concluded that four essential oils which were distilled from Cymbopogan citrates,Cinnamomum zeylanicum,Rosmarinus of ficinalis and Zingiber of ficinale showed promising larvicidal and repellent agent against Cx.tritaeniorhynchus and An.subpktus.
基金the Department of Science and Technology(DST,SERC-Fast Track Young Scientist Project), New Delhi,India for providing financial assistance for the present investigation
文摘ObjectiveTo determine the adulticidal and repellent activities of different solvent leaf extracts of Eclipta alba (E. alba) and Andrographis paniculata (A. paniculata) against malarial vector, Anopheles stephensi (An. stephensi).MethodsAdulticidal efficacy of the crude leaf extracts of E. alba and A. paniculata with five different solvents like benzene, hexane, ethyl acetate, methanol and chloroform was tested against the five to six day old adult female mosquitoes of An. stephensi. The adult mortality was observed after 24 h under the laboratory conditions. The repellent efficacy was determined against An. stephensi mosquito species at three concentrations viz., 1.0, 2.5 and 5.0 mg/cm2 under laboratory conditions.ResultsAmong the tested solvents the maximum efficacy was observed in the methanol extract. The LC50 and LC90 values of E. alba and A. paniculata against adults of An. stephensi were 150.36, 130.19 ppm and 285.22, 244.16 ppm, respectively. No mortality was observed in controls. The chi-square values were significant at P<0.05 level. Methanol extract of E. alba and A. paniculata was produce maximum repellency against An. stephensi.ConclusionsFrom the results it can be concluded the crude extract of E. alba and A. paniculata was an excellent potential for controlling An. stephensi mosquitoes.
文摘Objective:To test fumigant and repellent properties of sesquiterpene—rich essential oil from Teucrium polium subsp.capitation(L.).Methods:The fumigant toxicity test was performed at(27±1)℃.(65± 5)%relative humidity,and under darkness condition and 24 h exposure time.The chemical composition of the isolated oils was examined by gas chromatography—mass spectrometry.Results:The major compounds were α-cadiuol(46.2%),earyophyllene oxide(25.9%),α muurolol epi(8.1%),cadalene(3.7%) and longiverbenone(2.9%).In all cases,considerable differences in mortality of insect to essential oil vapor were observed in different concentrations and exposure times.Callosobruchus maculatus(C.maculates)(LC_(50)=148.9μL/L air) was more susceptible to the tested plant product than Teucrium castaneum(T.castaneum)(LC_(50)=360.2μL/L ain based on LC_(50)values.In the present investigation,the concentration of 3μ L /mL acetone showed 60% and 52% repellency against T.casteneum and C.maculatus adults,respectively.Conclusions:The results suggests that sesquiterpene—rich essential oils from the tested plant could be used as a potential control agent for stored—product insects.
文摘Objective:To formulate nanoemulsion from essential oils of Mentha(M.)piperita L.and Eucalyptus(E.)globulus L.and to compare their repellant activity with normal essential oils and N,N-diethyl-m toluamide(DEET)as a standard chemical compound.Methods:In this study,protection time of essential oils and DEET was evaluated on four human subjects using test cage,and their values were determined against Anopheles stephensi.Furthermore,ED50 values for the above essential oils were determined using the ASTM E951-94 method.The compositions of essential oils were determined using GC-MS,and droplet size and zeta potential of the nanoemulsion were measured with dynamic light scattering.Results:The results(expressed as mean±SD)showed that protection time of M.piperita 50%,M.piperita Nano 50%,E.globulus 50%,E.globulus Nano 50%,and DEET 25%was(2.89±0.45)h,(4.17±0.28)h,(0.96±0.27)h,(5.51±0.02)h,and(6.10±0.47)h,respectively.ED50 values were 29.10(95%CI:23.36-36.06)μg/cm^2 for Mentha,19.39(15.35-23.99)μg/cm^2 for Mentha Nano,36.10(28.70-48.01)μg/cm^2 for Eucalyptus,18.50(14.65-23.23)μg/cm^2 for Eucalyptus Nano,and 3.62(2.68-4.55)μg/cm^2 for DEET,respectively.E.globulus Nano and M.piperita Nano provided significantly longer protection than normal essential oils E.globulus and M.piperita(P<0.01).Conclusions:The preparation of nanoemulsion from the essential oils of M.piperita and E.globulus,significantly increases the protection time and reduces ED50 values of these essential oils,hence,M.piperita Nano and E.globulus Nano can be good alternatives to DEET and other chemical compounds.
文摘This paper introduces an effective anti-icing strategy that uses passive anti-icing property and active de-icing functions concurrently.These dual capabilities can alleviate the icing problem more effectively than either a passive or active function alone.The developed material is a slippery liquid-repellent elastic conductor(SLEC);it is an organogel that is composed of multi-walled carbon nanotubes,oil,and polydimethylsiloxane.The SLEC maintains passive water-droplet sliding ability even on wet surfaces that frequently occur in cold conditions(e.g.,during condensation and defrosting),suppresses ice nucleation,and shows ice adhesion strength as low as^20 kPa.The SLEC releases heat when it is subject to electrical or photonic stimulation,and can therefore it can prevent ice formation and melt ice that has already formed on a surface.This material has sustainable liquid repellence by syneresis and replenishment;this ability ensures long-lasting anti-icing property,and results in exceptional durability.This durability is stable against mechanical damage.The superior dual anti-icing capabilities together with the sustainable and stable liquid repellence should generate synergistic effects,and yield a powerful anti-icing tool that can broaden the range of icing applications.
基金the National Natural Science Foundation of China （No. 30170097）.
文摘Six species of wild rice with different ecophenotypes including Oryza grandiglumis （E6-1, E6-3 / 6-4）, O. minuta （E13-9, E13-13）, O. officinalis（E15-8, E15-13）, O. punctata （E16-1, E16-3, E16-13）, O. granulata（E7-4）, and O. latifolia（101392, E9-1, E9-10） were extracted with methnol and the repellent activity of the extracts against the two insects Aphis citricola and Panonychus citri were studied. The extracts of O. officinalis E15-8 showed higher repellent rate to the two insects than those of the other species. The repellent rates of the extracts of E15-8 to P. citriand A. citricola were 83.26% and 87.86% at 5×10^4 μg/mL in 24 h and 87.95% and 82.43% in 48 h, respectively. The extracts of O. officinalis E15-8 had the effect of inhibition to the esterase of the two insects.
基金supported by the National Basic Research Program of China(Grant No.2009CB421303)the National Natural Sciences Foundation(Grant Nos.40971031,40701002)
文摘Soil water repellency （SWR） is one of the most important physical properties of soils found all over the world, and it may have significant effects on the eco-hydrological processes of land ecosystems. In this study, the Capillary Rise Method was used to measure the SWR in the artificial vegetation area in Shapotou, located in the southeast area of the Tengger Desert, Ningxia Prov- ince of western China. The variation of the soil water repellency among different minor topographies, different depths and differ- ent particle sizes was analyzed. The results of the study indicate that the SWR shows distinct changes with vegetation restoration, and it increases with an increase in the period of dune stabilization. In the same vegetation area, the SWR of soils in inter-dune depressions or windward slopes is slightly greater than that in crest or leeward slopes. The SWR of 0-3 cm topsoil is significantly greater than that in the 3-6 cm soil layer. The SWR decreases with an increase in grain size and the differences among the SWRs of different sieved soil fractions are found to be significant. There is also a significantly positive correlation between the SWR and the proportion of soils with grain sizes of 0-0.05, 0.05-0.01 and 0.01-0.15 mm, and a significantly negative correlation between the SWR and the propotion of soils with grain sizes exceeding 0.15 mm. The increase of SWR in revegetation areas may depend on the continuous depositing of atmospheric dust on the stabilized dune surface as well as the formation of biological soil crusts, especially on the formation of algal and lichen crusts. Enhanced SWR influences the effectiveness of water use of sand plants in- habiting the sand dunes.
文摘Highlight Semaphorin 3A is a classically known axonal guidance cue that mediates axonal growth cone repulsion and collapse.Recent works,however,suggest that it may have the apparently diametrically opposite activity of promoting neuronal regeneration.
基金supported by Department of Science and Technology(DST.SERC-Fast Track Young Scientist Project-No.SR/FT/LS-072/2008).New Delhi.India
文摘Objective:To determine repellent activity of hexane,ethyl acetate,benzene,chloroform and methanol extract of Cardiospermum halicacabum,(C.halicacabum) against Culex quinque/ascialus(Cx.quinquefuscialus),Aedes aegypti(Ae.aegypli) and Anopheles slephensi(An.slephensi). Methods:Evaluation was carried out in a net cage(45 cm×30 cm×25 cm) containing 100 blood starved female mosquitoes of three mosquito species and were assayed in the laboratory condition by using the protocol of WHO 2005;The plant leaf crude extracts of C.halicacabum was applied at 1.0,2.5,and 5.0 me/cm^2 separately in the exposed area of the fore arm.Only ethanol served as control.Results:In this observation,the plant crude extracts gave protection against mosquito bites without any allergic reaction to the test person,and also,the repellent activity was dependent on the strength of the plant extracts.The tested plant crude extracts had exerted promising repellent against all the three mosquitoes.Conclusions:From the results it can be concluded the crude extract of C.halicacabum was potential for controlling Cx.quinquefasciatus, Ae.aegypli and An.slephensi mosquitoes.
文摘Objective:To investigate the larvicidal and repellent efficacy of tetradecanoic acid against Aedes aegrpti（Ae.aegypti） L,and Culex quinquefasciatus（Cx.quinquefasciatus） Say（Diptera: Culicidae）.Methods:Larvicidal efficacy of tetradecanoic acid was tested at various concentrations against the early third instar larvae of Ae.aegypti and Cx.quinquefasciatus. The repellent activity was determined against two mosquito species at three concentrations viz..1.0.2.5 and 5.0 ppm under the laboratory conditions.Results:The tetradecanoic acid was found to be more effective against Cx.quinquefasciatus than Ae.aegypti larvae.The LC<sub>50</sub> values were 14.08 ppm and 25.10 ppm,respectively.Tetradecanoic acid showed lesser repellency against Ae.aegypti and Cx.quinquefasciatus.The highest repellency was observed in higher concentration of 5.0 mg/cm<sup>2</sup> provided 100%protection up to 60 and 90 min against Ae.aegypti and Cx.quinquefasciatus respectively.Conclusions:From the results it can be concluded the tetradecanoic acid is a potential for controlling Cx.quinquefasciatus and Ae.aegypti mosquitoes.
基金supported by the National Natural Science Foundation of China (No. 51579213)the National Key Research and Development Program of China (No. 2017YFC0403303)
文摘Water-repellent(WR) soil greatly influences infiltration behavior. This research determined the impacts of WR levels of silt loam soil layer during infiltration. Three column scenarios were utilized, including homogeneous wettable silt loam or sand, silt loam over sand(silt loam/sand), and sand over silt loam(sand/silt loam). A 5-cm thick silt loam soil layer was placed either at the soil surface or 5 cm below the soil surface. The silt loam soil used had been treated to produce different WR levels, wettable, slightly WR, strongly WR, and severely WR. As the WR level increased from wettable to severely WR, the cumulative infiltration decreased. Traditional wetting front-related equations did not adequately describe the infiltration rate and time relationships for layered WR soils. The Kostiakov equation provided a good fit for the first infiltration stage. Average infiltration rates for wettable, slightly WR, strongly WR, and severely WR during the 2 nd infiltration stage were 0.126, 0.021, 0.002, and 0.001 mm min^(-1) for the silt loam/sand scenario,respectively, and 0.112, 0.003, 0.002, and 0.000 5 mm min^(-1) for the sand/silt loam scenario, respectively. Pseudo-saturation phenomena occurred when visually examining the wetting fronts and from the apparent changes in water content(?θ_(AP)) at the slightly WR,strongly WR, and severely WR levels for the silt loam/sand scenario. Much larger ?θAPvalues indicated the possible existence of finger flow. Delayed water penetration into the surface soil for the strongly WR level in the silt loam/sand scenario suggested negative water heads with infiltration times longer than 10 min. The silt loam/sand soil layers produced sharp transition zones of water content. The WR level of the silt loam soil layer had greater effects on infiltration than the layer position in the column.
基金National Natural Sci-ence Foundation of China(31670337)Research Project(ZYS2016-001)funded by Yunnan Key Laboratory for Wild Plant Resources.
文摘Zingiber cassumunar is an important plant used in traditional medicine and as a natural mosquito re-pellent.However,the compounds responsible for the repellent activity of the plant are still unknown.The aim of the study is to identify the components of Z.cassumunar essential oil that show repellent activity against Aedes albopictus.We also evaluated the larvicidal and adulticidal activities of Z.cassumunar essential oil against Ae.albopictus.In-cage mosquito repellent experiments showed that Z.cassumunar essential oil possessed moderate repellent activity with a minimum effective dose(MED)of 0.16±0.01 mg/cm^(20,compared to reference standard N,N-diethyl-3-methylbenzamide(DEET,0.03±0.01 mg/cm^(20).Bioassay-guided fractionation identified the major active compound of Z.cassumunar essential oil as(-)-terpinen-4-ol(1)(MED:0.19±0 mg/cm^(20).We also found that Z.cassumunar essential oil showed moderate larvicidal activity against first instar larvae of Ae.albopictus with a LC50(50%lethal concentration)of 44.9 mg/L after 24 h.Fumigation bioassays showed that Z.cassumunar essential oil exhibits moderate adulticidal activity against Ae.albopictus with a LC50 of 5.44%,while(-)-terpinen-4-ol showed significant adulticidal activity with a LC50 of 2.10%after 24 h.This study verifies that the Z.cassumunar essential oil has mosquito repellent activity,and that(-)-terpinen-4-ol is mainly responsible for this activity.Furthermore,this study provides scientific support for the folk usage of Z.cassumunar essential oil as mosquito repellent and indicates that Z.cassumunar essential oil and(-)-terpinen-4-ol can be used as plant-derived repellents and insecticides for mosquito control.
文摘Soil wettability and water repellency, two important soil physical properties, play an important role in water retention and water conductivity in arid and semi-arid regions. To date, there is a lack of information on soil water repellency in calcareous soils of western lran. In this study, soil water repellency and its affecting factors were studied using 20 soil series collected from Hamadan Province~ western Iran. The effects of soil properties including organic carbon content （SOC）, total nitrogen （TN）, C：N ratio, texture, CaCO3 content, and both fungal and bacterial activities on water repellency were investigated using air-dried, oven-dried and heated soil samples. Water repellency index （WRI） was determined using the short-time sorptivity （water/ethanol） method. To distinguish the actual effects of SOC, a set of soil samples were heated at 300 ~C to remove SOC and then WRI was measured on the heated samples. Relative water repellency index （RWRI） was defined as the change of WRI due to heating relative to the oven-dry WRI value. Results of the WRI values showed that the soils were sub-critically water-repellent. Pasture soils had higher WRI values compared to tilled soils, resulting from high SOC and TN, and high activities of bacteria and fungi. It was observed that SOC, TN, fungal activity, and SOC：clay ratio had significant positive impacts on WRI. Strong positive correlations of RWRI with SOC, TN and fungal activity were also observed. Pedotransfer functions derived for predicting WRI showed that the WRI values had an increasing trend with the increases in fungal activity, salinity, alkalinity and fine clay content, but showed a decreasing trend with increasing bacterial activity.
文摘Long lasting insect repellent curtain fabrics were developed and characterized. Different types of fabrics which are generally used in manufacture of curtain fabrics were functionalized with monochlorotriazenyl β-cyclodextrin (MCT-β-CD) then treated with different concentration from permethrin to impart the fabric insect repellent properties. These fabrics were 100% cotton, cotton/viscose, cotton/linen, polyester/cotton, polyester/linen and polyester/viscose blend fabrics. The treated curtain fabrics were evaluated for insect repellent retention capacity against mosquitoes. The repellent efficacy comprises the determination of percent mosquitoes repelled, knockdown and killed (mortality) resulting from exposed mosquitoes to the treated fabric. Results obtained shows that, the insect repellent retention capacity of curtain fabrics functionalized with R-β-CD then treated with permethrin depends on the amount of β-CD moieties on the curtain fabrics, type of fabric and permethrin concentration. Higher action is obtained when the fabric was functionalized with 100 g/L, MCT-β-CD in alkaline medium followed by treatment with 15 g/L permethrin. The results show also that, curtain fabric made of cotton/linen shows highest mosquitoes repellent retention capacity and highest resistance against washing compared with 100% cotton or cotton/viscose or polyester based curtain fabrics. The insect repellent treatment of curtain fabrics did not adversely affect the tensile strength or drapability index of curtain
