We consider the dynamics of a transcendental meromorphic function f(z) with only finitely many poles and prove that if f has only finitely many weakly repelling fixed points,then there is no multiply-connected wanderi...We consider the dynamics of a transcendental meromorphic function f(z) with only finitely many poles and prove that if f has only finitely many weakly repelling fixed points,then there is no multiply-connected wandering domain in its Fatou set.展开更多
Let R(z) be a rational function of degree d ≥ 2. Then R(z) has at least one repelling periodic point of given period k ≥ 2, unless k = 4 and d=2, or k= 3 and d ≤ 3, or k=2 and d≤8. Examples show that all exception...Let R(z) be a rational function of degree d ≥ 2. Then R(z) has at least one repelling periodic point of given period k ≥ 2, unless k = 4 and d=2, or k= 3 and d ≤ 3, or k=2 and d≤8. Examples show that all exceptional cases occur.展开更多
Birds are a huge hazard to agriculture all around the world,causing harm to profitable field crops.Growers use a variety of techniques to keep them away,including visual,auditory,tactile,and olfactory deterrents. This...Birds are a huge hazard to agriculture all around the world,causing harm to profitable field crops.Growers use a variety of techniques to keep them away,including visual,auditory,tactile,and olfactory deterrents. This study presents a comprehensive overview of current bird repellant approaches used in agricultural contexts,as well as potential new ways. The bird repellent techniques include Internet of Things technology,Deep Learning,Convolutional Neural Network,Unmanned Aerial Vehicles,Wireless Sensor Networks and Laser biotechnology. This study’s goal is to find and review about previous approach towards repellent of birds in the crop fields using various technologies.展开更多
Water repellant,flexible biofoams using tannin esterified with various fatty acid chains,namely lauric,palmitic and oleic acids,by reaction with lauryl chloride,palmitoyl chloride,and oleyl chloride were developed and...Water repellant,flexible biofoams using tannin esterified with various fatty acid chains,namely lauric,palmitic and oleic acids,by reaction with lauryl chloride,palmitoyl chloride,and oleyl chloride were developed and their characteristics compared with the equivalently esterified rigid biofoams.Glycerol,while initially added to control the reaction temperature,was used as a plasticizer yielding flexible biofoams presenting the same water repellant character that the equivalent rigid foams.Acetaldehyde was used as the cross-linking agent instead of formaldehyde,as it showed a better performance with the esterified tannin.The compression results showed a significant decrease of the Modulus of Elasticity(MOE)of the flexible foams in relation to that of the rigid foams,confirming their flexible character.The lauryl-and palmitoyl-esterified biofoams presented similar mechanical properties,while the oleyl-esterified biofoam presented different mechanical and morphological result not really showing the expected flexibility.Both the esterified rigid and flexible tannin-based biofoams showed good water resistance and their sessile drop contact angle analysis as a function of time confirmed this characteristic.Scanning Electron Microscope(SEM)analysis showed the flexible foams to present a higher proportion of closed cells than the rigid foams.Conversely,the cells depth of the flexible foams was lower than that of the rigid foam.As regards their thermal resistance,the flexible foams showed a slight loss of mass compared to the rigid ones without glycerol.Both types of foams presented much lower surface friability of non-esterified rigid foams.展开更多
Mosquitoes are of great concern for occasionally carrying noxious diseases(dengue,malaria,zika,and yellow fever).To control mosquitoes,it is very crucial to effectively monitor their behavioral trends and presence.Tra...Mosquitoes are of great concern for occasionally carrying noxious diseases(dengue,malaria,zika,and yellow fever).To control mosquitoes,it is very crucial to effectively monitor their behavioral trends and presence.Traditional mosquito repellent works by heating small pads soaked in repellant,which then diffuses a protected area around you,a great alternative to spraying yourself with insecticide.But they have limitations,including the range,turning them on manually,and then waiting for the protection to kick in when the mosquitoes may find you.This research aims to design a fuzzy-based controller to solve the above issues by automatically determining a mosquito repellent’s speed and active time.The speed and active time depend on the repellent cartridge and the number of mosquitoes.The Mamdani model is used in the proposed fuzzy system(FS).The FS consists of identifying unambiguous inputs,a fuzzification process,rule evaluation,and a defuzzification process to produce unambiguous outputs.The input variables used are the repellent cartridge and the number of mosquitoes,and the speed of mosquito repellent is used as the output variable.The whole FS is designed and simulated using MATLAB Simulink R2016b.The proposed FS is executed and verified utilizing a microcontroller using its pulse width modulation capability.Different simulations of the proposed model are performed in many nonlinear processes.Then,a comparative analysis of the outcomes under similar conditions confirms the higher accuracy of the FS,yielding a maximum relative error of 10%.The experimental outcomes show that the root mean square error is reduced by 67.68%,and the mean absolute percentage error is reduced by 52.46%.Using a fuzzy-based mosquito repellent can help maintain the speed of mosquito repellent and control the energy used by the mosquito repellent.展开更多
Aminated tannins were prepared by reacting mimosa condensed tannin extract with ammonia yielding the substitution of many,if not all of the tannin hydroxyl groups with–NH_(2)groups.A tannin-aminated tannin(ATT)partic...Aminated tannins were prepared by reacting mimosa condensed tannin extract with ammonia yielding the substitution of many,if not all of the tannin hydroxyl groups with–NH_(2)groups.A tannin-aminated tannin(ATT)particleboard coating was then prepared by reacting raw tannin extract with aminated tannin extract and thus cross-linking the two by substituting tannin’s hydroxyl groups with the–NH_(2)groups on the aminated tannin to form–NH-bridges between the two.The resulting particleboard coating gave encouraging results when pressed at 180℃for 3 min.Conversely,the system in which tannin was reacted/cross-liked with urea(ATU)by a similar amination reaction did not perform as well as the ATT system,and this even when a higher curing temperature and longer hot press time were used.In particular its water repellence was worse probably due to the presence of urea and such a system with lower reactivity.Nonetheless,substituting the tannin–OHs with the urea–NH_(2)groups appeared to also take place.ATT gave better results than ATU as regards water repellence and mechanical resistance as shown by the cross cut test.The ATT system was shown to be between 95%and 98%biosourced.The difference appeared to be due,by TMA analysis,to the much faster formation of the ATT hardened network leading to a better cross-linked polymer coating.The chemical species formed for both the ATT and ATU system were studied by MALDI ToF and CP MAS^(13)C NMR.展开更多
We establish sufficient conditions of the multiplicity of real fixed points of two-parameter family . Moreover, the behaviors of these fixed points are studied.
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
Thirteen volatile compounds were identified from Flemingia macrophylla plants. Eight major components significantly attracted the tea green leafhoppers, Empoasca flavescens F. Based on their relative abundances, follo...Thirteen volatile compounds were identified from Flemingia macrophylla plants. Eight major components significantly attracted the tea green leafhoppers, Empoasca flavescens F. Based on their relative abundances, following synthetic blends were made for field experiments: 1) eight-component-attractant blend included Z-3-hexen-1-ol, Z-3-hexenyl acetate, Z-ocimene, Me SA, Z-3-hexenyl butyrate, dodecane, hexadecane and nonanal at 10, 10, 1, 11, 2, 6, 2 and 4 mg mL^-1 in n-hexane, respectively;2) four-component-attractant blend #1 contained hexadecane, Z-3-hexenyl acetate, Z-3-hexen-1-ol and nonanal at 2, 10, 10 and 4 mg mL^-1 in n-hexane, respectively;3) four-component-attractant blend #2 contained hexadecane, Z-3-hexenyl acetate, Z-3-hexen-1-ol and Me SA at 2, 10, 10 and 11 mg mL^-1 in n-hexane, respectively. Thymol and 1-methoxy-4-methyl-2-(1-methylethyl)-benzene, identified from Lavandula angustifolia aeration samples, significantly repelled the leafhopper as strong repellents when tested alone or in combination at 10 mg mL^-1. For field bioassays, each attractant lure was attached to a bud green sticky board hung from a bamboo stick at above tea plant level for catching the leafhoppers, whereas the repellent dispenser was tied to a tea branch inside tea clump for pushing the leafhoppers away from tea clumps. The results showed that the eight-component-attractant blend caught similar numbers of the leafhopper as did the four-component-attractant blend #1 at about 53–79 leafhoppers/trap/day, which were significantly higher than those on the hexane-control bud green sticky boards. Average leafhopper catches from un-baited sticky boards were about 51–73 leafhoppers/trap/day when pushed by the repellents placed inside tea plants, with the two-component-repellent blend being more effective than their single components. When the two-component-repellent blend was further tested with the three attractant blends in a push-pull fashion, average trap catches ranged from 62 to 92 leafhoppers/trap/day. Control efficacy on the leafhoppers within the push-pull zones increased progressively from day 1(43%) to day 5(73%). This push-pull approach might have a great potential as a green control strategy for combating the tea green leafhoppers.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 assess the larvicidal and repellent potential of the essential oil extracted from the leaves of peppermint plant,Mentha piperita(M.piperita)against the larval and adult stages of Aedes aegypli(Ae.Aegypti)...Objective:To assess the larvicidal and repellent potential of the essential oil extracted from the leaves of peppermint plant,Mentha piperita(M.piperita)against the larval and adult stages of Aedes aegypli(Ae.Aegypti).Methods:The larvicidal potential of peppermint oil was evaluated against early fourth instar larvae of Ae.aegypli using WHO protocol.The mortality counts were made after 24 and 48 h,and LC_(50)and LC_(90)values were calculated.The efficacy of peppermint oil as mosquito repellent was assessed using the human-bait technique.The measured area of one arm of a human volunteer was applied with the oil and the other arm was applied with ethanol.The mosquito bites on both the arms were recorded for 3 rain after every 15 min.The experiment continued for 3 h and the percent protection was calculated.Results:The essential oil extracted from M.piperita possessed excellent larvicidal efficiency against dengue vector.The bioassays showed an LC_(50)and LC_(90)value of 111.9 and 295.18 ppm,respectively after 24 h of exposure.The toxicity of the oil increased 11.8%when the larvae were exposed to the oil for 48h.The remarkable repellent properties of M.piperita essential oil were established against adults Ae.aegypti.The application of oil resulted in 100%protection till 150 min.After next 30 min,only 1-2 bites were recorded as compared with 8-9 bites on the control arm.Conclusions:The peppermint essential oil is proved to be efficient larvicide and repellent against dengue vector.Further studies are needed to identify the possible role of oil as adulticide.oviposition deterrent and ovicidal agent.The isolation of active ingredient from the oil could help in formulating strategies for mosquito control.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
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
To 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...To 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)Mathods:Adultieidal efficacy of the crude leaf extracts of E.alba and.1.paniculata with five different solvents like benzene,hexane.ethyl acetate. methanol and chloroform was tested against the five to six dav 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/cm<sup>2</sup> under laboratory conditions.Results:Among the tested solvents the maximum efficacy was observed in the methanol extract.The LC<sub>50</sub> and LC<sub>90</sub> 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 obsened in controls.The chi-square values were significant at P【0.05 lev el.Methanol extract of E.alba and A.paniculata was produce maximum repellency against An.stephensi.Conclusions:From the results it can be concluded the crude extract of E. nihil and A.paniculata was an excellent potential for controlling An.stephensi mosquitoes.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
Hematophagous invertebrates such as mosquitoes,leeches,mites,ticks,lice and bugs cause various problems for humans.Considering reports on insecticide resistance and requirements for improved environmental and toxicolo...Hematophagous invertebrates such as mosquitoes,leeches,mites,ticks,lice and bugs cause various problems for humans.Considering reports on insecticide resistance and requirements for improved environmental and toxicological profiles,there is a continuing need to discover and develop new insecticides and repellents.Ethnobotanical surveys of traditional plant-based repellents provide a direct method of identifying plants for potential use.During five field surveys in Bulang,Jinuo and Lahu villages between August 2018 and July 2019,semi-structured interviews were conducted with 237 informants(151 male,86 female;mean age 63).Frequency of citation,use value,informant consensus factor and Jaccard index were employed to statistically analyze the collected data.A total of 709 use reports relating to 32 plant species and 71 remedies were collected.Similarities and differences between the three groups,as well as the Dai and Hani of Xishuangbanna,who were studied earlier,were shown through network analysis.These five ethnic groups living in the same area have a common understanding of traditional botanical knowledge against hematophagous invertebrates,but each group also possesses unique knowledge.Recording and protecting this traditional knowledge is potentially useful for protecting this cultural diversity and related biodiversity and can also have important practical applications.In this study,traditional knowledge provided us with many new potential plants for follow-up research for the development of new insecticides and repellents,among which Artemisia indica,Nicotiana tabacum and Clausena excavata are the most promising.展开更多
Water striders have intrigued researchers for centuries from the viewpoints of biology to biomechanics. In this review, we introduce the basic theories and techniques of physics and force measurement for biomechanical...Water striders have intrigued researchers for centuries from the viewpoints of biology to biomechanics. In this review, we introduce the basic theories and techniques of physics and force measurement for biomechanical research into water striders. Morphological and behavioral traits of water striders are summarized and discussed from biomechanical perspectives, along with comparative study. This integrated review also highlights potential directions for studies on water-walking arthropods,which might inspire future biological and biomechanical research.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
基金supported by the National Natural Science Foundation of China(Grant No.10231040)the Doctoral Education Program Foundation of China.
文摘We consider the dynamics of a transcendental meromorphic function f(z) with only finitely many poles and prove that if f has only finitely many weakly repelling fixed points,then there is no multiply-connected wandering domain in its Fatou set.
文摘Let R(z) be a rational function of degree d ≥ 2. Then R(z) has at least one repelling periodic point of given period k ≥ 2, unless k = 4 and d=2, or k= 3 and d ≤ 3, or k=2 and d≤8. Examples show that all exceptional cases occur.
文摘Birds are a huge hazard to agriculture all around the world,causing harm to profitable field crops.Growers use a variety of techniques to keep them away,including visual,auditory,tactile,and olfactory deterrents. This study presents a comprehensive overview of current bird repellant approaches used in agricultural contexts,as well as potential new ways. The bird repellent techniques include Internet of Things technology,Deep Learning,Convolutional Neural Network,Unmanned Aerial Vehicles,Wireless Sensor Networks and Laser biotechnology. This study’s goal is to find and review about previous approach towards repellent of birds in the crop fields using various technologies.
基金The Malaysia-France Bilateral Research Collaboration Project Grant 2021 (MATCH 2021)funded this research work,MOHE-Fire-Resistant and Water-Repellent Tannin-Furanic-Fatty Acid Biofoams。
文摘Water repellant,flexible biofoams using tannin esterified with various fatty acid chains,namely lauric,palmitic and oleic acids,by reaction with lauryl chloride,palmitoyl chloride,and oleyl chloride were developed and their characteristics compared with the equivalently esterified rigid biofoams.Glycerol,while initially added to control the reaction temperature,was used as a plasticizer yielding flexible biofoams presenting the same water repellant character that the equivalent rigid foams.Acetaldehyde was used as the cross-linking agent instead of formaldehyde,as it showed a better performance with the esterified tannin.The compression results showed a significant decrease of the Modulus of Elasticity(MOE)of the flexible foams in relation to that of the rigid foams,confirming their flexible character.The lauryl-and palmitoyl-esterified biofoams presented similar mechanical properties,while the oleyl-esterified biofoam presented different mechanical and morphological result not really showing the expected flexibility.Both the esterified rigid and flexible tannin-based biofoams showed good water resistance and their sessile drop contact angle analysis as a function of time confirmed this characteristic.Scanning Electron Microscope(SEM)analysis showed the flexible foams to present a higher proportion of closed cells than the rigid foams.Conversely,the cells depth of the flexible foams was lower than that of the rigid foam.As regards their thermal resistance,the flexible foams showed a slight loss of mass compared to the rigid ones without glycerol.Both types of foams presented much lower surface friability of non-esterified rigid foams.
文摘Mosquitoes are of great concern for occasionally carrying noxious diseases(dengue,malaria,zika,and yellow fever).To control mosquitoes,it is very crucial to effectively monitor their behavioral trends and presence.Traditional mosquito repellent works by heating small pads soaked in repellant,which then diffuses a protected area around you,a great alternative to spraying yourself with insecticide.But they have limitations,including the range,turning them on manually,and then waiting for the protection to kick in when the mosquitoes may find you.This research aims to design a fuzzy-based controller to solve the above issues by automatically determining a mosquito repellent’s speed and active time.The speed and active time depend on the repellent cartridge and the number of mosquitoes.The Mamdani model is used in the proposed fuzzy system(FS).The FS consists of identifying unambiguous inputs,a fuzzification process,rule evaluation,and a defuzzification process to produce unambiguous outputs.The input variables used are the repellent cartridge and the number of mosquitoes,and the speed of mosquito repellent is used as the output variable.The whole FS is designed and simulated using MATLAB Simulink R2016b.The proposed FS is executed and verified utilizing a microcontroller using its pulse width modulation capability.Different simulations of the proposed model are performed in many nonlinear processes.Then,a comparative analysis of the outcomes under similar conditions confirms the higher accuracy of the FS,yielding a maximum relative error of 10%.The experimental outcomes show that the root mean square error is reduced by 67.68%,and the mean absolute percentage error is reduced by 52.46%.Using a fuzzy-based mosquito repellent can help maintain the speed of mosquito repellent and control the energy used by the mosquito repellent.
基金supported by a grant of the French Agence Nationale de la Recherche(ANR)in the Ambit of the Laboratory of Excellence(Labex)ARBRE.This work was also supported by“The 111 Project(D21027)”.
文摘Aminated tannins were prepared by reacting mimosa condensed tannin extract with ammonia yielding the substitution of many,if not all of the tannin hydroxyl groups with–NH_(2)groups.A tannin-aminated tannin(ATT)particleboard coating was then prepared by reacting raw tannin extract with aminated tannin extract and thus cross-linking the two by substituting tannin’s hydroxyl groups with the–NH_(2)groups on the aminated tannin to form–NH-bridges between the two.The resulting particleboard coating gave encouraging results when pressed at 180℃for 3 min.Conversely,the system in which tannin was reacted/cross-liked with urea(ATU)by a similar amination reaction did not perform as well as the ATT system,and this even when a higher curing temperature and longer hot press time were used.In particular its water repellence was worse probably due to the presence of urea and such a system with lower reactivity.Nonetheless,substituting the tannin–OHs with the urea–NH_(2)groups appeared to also take place.ATT gave better results than ATU as regards water repellence and mechanical resistance as shown by the cross cut test.The ATT system was shown to be between 95%and 98%biosourced.The difference appeared to be due,by TMA analysis,to the much faster formation of the ATT hardened network leading to a better cross-linked polymer coating.The chemical species formed for both the ATT and ATU system were studied by MALDI ToF and CP MAS^(13)C NMR.
文摘We establish sufficient conditions of the multiplicity of real fixed points of two-parameter family . Moreover, the behaviors of these fixed points are studied.
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.
基金financially supported by the National Key Research and Development Program of China (2018YFC1604402)the Natural Science Foundation of Zhejiang Province, China (LY17C140002)+1 种基金the Fundamental and Public Welfare of Zhejiang Province, China (LGN18C160006)the College Student Innovation and Entrepreneurship of Zhejiang Province, China (2017R409055)
文摘Thirteen volatile compounds were identified from Flemingia macrophylla plants. Eight major components significantly attracted the tea green leafhoppers, Empoasca flavescens F. Based on their relative abundances, following synthetic blends were made for field experiments: 1) eight-component-attractant blend included Z-3-hexen-1-ol, Z-3-hexenyl acetate, Z-ocimene, Me SA, Z-3-hexenyl butyrate, dodecane, hexadecane and nonanal at 10, 10, 1, 11, 2, 6, 2 and 4 mg mL^-1 in n-hexane, respectively;2) four-component-attractant blend #1 contained hexadecane, Z-3-hexenyl acetate, Z-3-hexen-1-ol and nonanal at 2, 10, 10 and 4 mg mL^-1 in n-hexane, respectively;3) four-component-attractant blend #2 contained hexadecane, Z-3-hexenyl acetate, Z-3-hexen-1-ol and Me SA at 2, 10, 10 and 11 mg mL^-1 in n-hexane, respectively. Thymol and 1-methoxy-4-methyl-2-(1-methylethyl)-benzene, identified from Lavandula angustifolia aeration samples, significantly repelled the leafhopper as strong repellents when tested alone or in combination at 10 mg mL^-1. For field bioassays, each attractant lure was attached to a bud green sticky board hung from a bamboo stick at above tea plant level for catching the leafhoppers, whereas the repellent dispenser was tied to a tea branch inside tea clump for pushing the leafhoppers away from tea clumps. The results showed that the eight-component-attractant blend caught similar numbers of the leafhopper as did the four-component-attractant blend #1 at about 53–79 leafhoppers/trap/day, which were significantly higher than those on the hexane-control bud green sticky boards. Average leafhopper catches from un-baited sticky boards were about 51–73 leafhoppers/trap/day when pushed by the repellents placed inside tea plants, with the two-component-repellent blend being more effective than their single components. When the two-component-repellent blend was further tested with the three attractant blends in a push-pull fashion, average trap catches ranged from 62 to 92 leafhoppers/trap/day. Control efficacy on the leafhoppers within the push-pull zones increased progressively from day 1(43%) to day 5(73%). This push-pull approach might have a great potential as a green control strategy for combating the tea green leafhoppers.
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 assess the larvicidal and repellent potential of the essential oil extracted from the leaves of peppermint plant,Mentha piperita(M.piperita)against the larval and adult stages of Aedes aegypli(Ae.Aegypti).Methods:The larvicidal potential of peppermint oil was evaluated against early fourth instar larvae of Ae.aegypli using WHO protocol.The mortality counts were made after 24 and 48 h,and LC_(50)and LC_(90)values were calculated.The efficacy of peppermint oil as mosquito repellent was assessed using the human-bait technique.The measured area of one arm of a human volunteer was applied with the oil and the other arm was applied with ethanol.The mosquito bites on both the arms were recorded for 3 rain after every 15 min.The experiment continued for 3 h and the percent protection was calculated.Results:The essential oil extracted from M.piperita possessed excellent larvicidal efficiency against dengue vector.The bioassays showed an LC_(50)and LC_(90)value of 111.9 and 295.18 ppm,respectively after 24 h of exposure.The toxicity of the oil increased 11.8%when the larvae were exposed to the oil for 48h.The remarkable repellent properties of M.piperita essential oil were established against adults Ae.aegypti.The application of oil resulted in 100%protection till 150 min.After next 30 min,only 1-2 bites were recorded as compared with 8-9 bites on the control arm.Conclusions:The peppermint essential oil is proved to be efficient larvicide and repellent against dengue vector.Further studies are needed to identify the possible role of oil as adulticide.oviposition deterrent and ovicidal agent.The isolation of active ingredient from the oil could help in formulating strategies for mosquito control.
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.
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.
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To 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)Mathods:Adultieidal efficacy of the crude leaf extracts of E.alba and.1.paniculata with five different solvents like benzene,hexane.ethyl acetate. methanol and chloroform was tested against the five to six dav 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/cm<sup>2</sup> under laboratory conditions.Results:Among the tested solvents the maximum efficacy was observed in the methanol extract.The LC<sub>50</sub> and LC<sub>90</sub> 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 obsened in controls.The chi-square values were significant at P【0.05 lev el.Methanol extract of E.alba and A.paniculata was produce maximum repellency against An.stephensi.Conclusions:From the results it can be concluded the crude extract of E. nihil and A.paniculata was an excellent potential for controlling An.stephensi mosquitoes.
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.
基金This study was supported by grant from the National Natural Science Foundation of China[31670337]Plant Germplasm Resources Innovation Project of Chinese Academy of Sciences[KFJBRP-007-002].
文摘Hematophagous invertebrates such as mosquitoes,leeches,mites,ticks,lice and bugs cause various problems for humans.Considering reports on insecticide resistance and requirements for improved environmental and toxicological profiles,there is a continuing need to discover and develop new insecticides and repellents.Ethnobotanical surveys of traditional plant-based repellents provide a direct method of identifying plants for potential use.During five field surveys in Bulang,Jinuo and Lahu villages between August 2018 and July 2019,semi-structured interviews were conducted with 237 informants(151 male,86 female;mean age 63).Frequency of citation,use value,informant consensus factor and Jaccard index were employed to statistically analyze the collected data.A total of 709 use reports relating to 32 plant species and 71 remedies were collected.Similarities and differences between the three groups,as well as the Dai and Hani of Xishuangbanna,who were studied earlier,were shown through network analysis.These five ethnic groups living in the same area have a common understanding of traditional botanical knowledge against hematophagous invertebrates,but each group also possesses unique knowledge.Recording and protecting this traditional knowledge is potentially useful for protecting this cultural diversity and related biodiversity and can also have important practical applications.In this study,traditional knowledge provided us with many new potential plants for follow-up research for the development of new insecticides and repellents,among which Artemisia indica,Nicotiana tabacum and Clausena excavata are the most promising.
基金the National Natural Science Foundation of China(51425502)。
文摘Water striders have intrigued researchers for centuries from the viewpoints of biology to biomechanics. In this review, we introduce the basic theories and techniques of physics and force measurement for biomechanical research into water striders. Morphological and behavioral traits of water striders are summarized and discussed from biomechanical perspectives, along with comparative study. This integrated review also highlights potential directions for studies on water-walking arthropods,which might inspire future biological and biomechanical research.
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.