Gas Chromaotography-Mass Spectrometry Analysis of Insecticidal Essential Oil Derived from Chinese Ainsliaea fragrans Champ ex Benth (Compositae)

Purpose: To investigate the chemical composition and insecticidal activity of the essential oil of the aerial parts of Ainsliaea fragrans against maize weevils (Sitophilus zeamais).Methods: The essential oil of A. fragrans aerial parts was obtained by hydrodistillation and analyzed by gas chromatography (GC) and gas chromaotography-mass spectrometry (GC-MS). Contact toxicity of the essential oil and its major constituents was determined by topical application against S. zeamais.Results: A total of 30 components of the essential oil were identified. The major constituents were myristicin (41.3 %), elemicine (11.9 %), cis-isosafrole (11.5 %), borneol (9.1 %) and caryophyllene (8.8 %). The essential oil of A. fragrans exhibited contact toxicity against S. zeamais with LC50 value of 50.7 μg/adult. Elemicine possessed the strongest contact toxicity (LC50 = 13.5 μg/adult) while cis-isosafrole, myristicin, caryophyllene and borneol had LC50 values of 31.2 μg/adult, 43.4 μg/adult, 57.9 μg/adult, and 98.4 μg/adult, respectively.Conclusion: The study indicates that the essential oil of A. fragrans aerial parts and its major constituents have a potential for development into natural insecticides for the control of grain storage insects.Keywords: Ainsliaea fragrans, Sitophilus zeamais, Contact toxicity, Elemicine, Essential oil, Grain storag

Larvicidal activity of Illicium difengpi BN Chang (Schisandraceae) Stem Bark and its Constituent Compounds against Aedes aegypti L

Purpose: To determine the larvicidal activity of the essential oil derived from Illicium difengpi B.N. Chang stem bark (Schisandraceae) and its major constituents against the larvae of Aedes aegypti L.Methods: Essential oil of I. difengpi stem bark was obtained by hydrodistillation and analyzed by gas chromatography (GC) and gas chromaotography-mas spectrometry (GC-MS). The activity of the essential oil and its major constituents was evaluated, using World Health Organization (WHO) procedures, against the fourth instar larvae of A. aegypti for 24 h, and larval mortalities recorded at essential oil/compound concentrations ranging from 6.0 - 200 μg/mL.Results: A total of 36 components of the essential oil of I. difengpi were identified. The principal compounds are safrole (18.21 %), linalool (13.47 %), 1,8-cineole (12.84 %), and myristicin (8.06 %) followed by α-terpineol (4.77 %), β-pinene (4.45 %) and 4-terpineol (4.38 %). The essential oil exhibited larvicidal activity against A. aegypti with LC50 (median lethal concentration) of 31.68 μg/mL. The major constituents, myristicin, safrole, and 1, 8-cineole, exhibited LC50 of 15.26, 39.45, and 72.18 μg/mL, respectively.Conclusion: The findings obtained indicate that the essential oil of I. difengpi and its major constituents have potentials for use in the control of A. aegypti larvae and may therefore be useful in the search for newer, safer and more effective natural compounds as larvicides.Keywords: Illicium difengpi, Aedes aegypti, Larvicidal activity, Myristicin, Safrole, 1,8-Cineole, Linaloo

Quadtree based mouse trajectory analysis for efficacy evaluation of voice-enabled CAD

Voice-enabled applications have caught considerable research interest in recent years. It is generally believed that voice based interactions can improve the working efficiencies and the overall productivities. Quantitative evaluations on the performance boost by using such Human-Computer interactions (HCI) are therefore necessary to justify the claimed efficacies and the usefulness of the HCI system. In this paper, a quadtree based approach is proposed to analyze the mouse movement distributions in the proposed Voice-enabled Computer-Aided Design (VeCAD) system. The mouse tracker keeps a record of all the mouse movement during the solid modeling process, and a quadtree based approach is applied to analyze the mouse trajectory distributions in both the traditional CAD and the VeCAD system. Our experiments show that the mouse movement is significantly reduced when voice is used to activate CAD modeling commands. ©2009 IEEE.published_or_final_versionThe IEEE International Conference on Virtual Environments, Human-Computer Interfaces, and Measurements Systems (VECIMS) 2009, Hong Kong, 11-13 May 2009. In Conference Proceedings, 2009, p. 196-20

Chemical Composition of Salvia plebeian R.Br. Essential Oil and its Larvicidal Activity against Aedes aegypti L

Purpose: To evaluate the larvicidal activity of the essential oil of Salvia plebeian R.Br. (Labiatae) aerial parts against the larvae of Aedes aegypti L.Methods: The essential oil of S. plebeian aerial parts was obtained by hydro-distillation and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The essential oil was evaluated for larvicidal activity using World Health Organization (WHO) procedures, against the fourth larvae of A. aegypti within 24 h, and activity was recorded for various concentrations of the ranging from 12.5 – 200.0 μg/mL.Results: A total of 33 components of the essential oil of S. plebeian were identified. The major compounds of the essential oil were caryophyllene oxide (15.54 %), γ-eudesmol (14.03 %), τ-cadinol (10.21 %), calamenene (9.63 %), copaene (5.70 %), γ-cadinene (5.30 %), cadalene (5.28 %), α- muurolene (5.19 %), ledol (5.14 %) and α-cadinol (5.08 %). The essential oil exhibited larvicidal activity against A. aegypti at a median lethal concentration (LC50) of 46.26 μg/mL.Conclusion: The findings indicate that the essential oil of S. plebeian aerial parts has potentials for use in the control of A. aegypti larvae and may be useful in the search for newer, safer and more effective natural compounds as larvicides.Keywords: Salvia plebeian, Essential oil, Larvicidal activity, Aedes aegypti, Caryophyllene oxide, γ- Eudesmol, τ-Cadinol, Calamenen

Insecticidal activity of essential oil of Cinnamomum cassia and its main constituent, trans-Cinnamaldehyde, against the booklice, Liposcelis bostrychophila

Purpose: To investigate the insecticidal activity of the essential oil of Cinnamomum cassis and its main constituent compound, trans-cinnamaldehyde, against the booklice, Liposcelis bostrychophila．Methods: Steam distillation of C. cassis twigs was carried out using a Clavenger apparatus in order to obtain the volatile oils. Gas chromatography/mass spectrometric (GC/MS) analyses (HP-5MS column) of the essential oil were performed and its contact (using impregnated filter paper method) and fumigant toxicity (sealed space) determined. The bioactive constituent compound, trans-cinnamaldehyde was isolated and identified from the oil based on bioactivity-directed fractionation.Results: A total of 35 components, accounting for 97.44 % of the essential oil of C. cassis, were identified. The principal compounds in the essential oil were trans-cinnamaldehyde (49.33 %), acetophenone (6.94 %), trans-cinnamic acid (5.45 %) and cis-cinnamaldehyde (4.44 %) followed by omethoxycinnamaldehyde (3.48 %), coumarin (3.42 %) and (E)-cinnamyl alcohol (3.21 %). The essential oil displayed contact toxicity against adult L. bostrychophila with a median lethal concentration (LC50) of 55.68 μg/cm2 as well as fumigant toxicity (LC50, 1.33 mg/l air). Trans-cinnamaldehyde exhibited strong contact and fumigant toxicity with LC50 and 1.29 mg/l air, respectively.Conclusion: The findings suggest that the essential oil of C. cassis and its constituent compound, trans-cinnamaldehyde, possess potentials for development into natural fumigants/insecticides for the control of booklice.Keywords: Liposcelis bostrychophila, Cinnamomum cassis, Contact toxicity, Fumigant, trans- Cinnamaldehyde, Essential oi

Chemical Composition and Insecticidal Activity of Essential Oil of Artemisia frigida Willd (Compositae) against Two Grain Storage Insects

Purpose: To investigate the chemical composition and insecticidal activity of the essential oil of the aerial parts of Artemisia frigida against maize weevils (Sitophilus zeamais) and booklice (Liposcelis bostrychophila)DMethods: Steam distillation of A. frigida aerial parts was carried out in a Clavenger apparatus to extract its volatile oil content. Gas  chromatography/mass spectrometric (GC/MS) analyses (HP-5MS column) ofthe essential oil were performed and its contact toxicity was determined using topical application and filter paper impregnation technique while its fumigant toxicity was evaluated using sealed-space method.Results: A total of 32 components of the essential oil were identified. The principal compounds were cis-ρ-menth-2-en-1-ol (20.8%), 1,8-cineole (12.0%), borneol (10.2%), lavandulol (9.3%), camphor (6.9%), and bicyclogermacrene (5.5%). The oil exhibited contact toxicity against adult S. zeamais and L. bostrychophila with LC50 value of 17.97 µg/adult and 254.38 µg/cm2, respectively. The essential oils also possessed fumigant toxicity against S. zeamais and L. bostrychophila with LC50 value of 69.46mg/L and 1.25 mg/L air.Conclusion: The study indicates that the essential oil of A. frigida has a potential to be developed to a natural fumigant/insecticide for the control of grain storage insects.Keywords: Artemisia frigida, Sitophilus zeamais, Liposcelis bostrychophila, Insecticidal activity, Essential oil, Cis-ρ-Menth-2-en-1-ol; 1,8-Cineol

Substituent Effects on the Photodeprotection Reactions of Selected Ketoprofen Derivatives in Phosphate Buffered Aqueous Solutions

published_or_final_versio

A quantitative link between microplastic instability and macroscopic deformation behaviors in metallic glasses

2009-2010 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

A quantitative link between microplastic instability and macroscopic deformation behaviors in metallic glasses

Based on mechanical instability of individual shear transformation zones (STZs), a quantitative link between the microplastic instability and macroscopic deformation behavior of metallic glasses was proposed. Our analysis confirms that macroscopic metallic glasses comprise a statistical distribution of STZ embryos with distributed values of activation energy, and the microplastic instability of all the individual STZs dictates the macroscopic deformation behavior of amorphous solids. The statistical model presented in this paper can successfully reproduce the macroscopic stress-strain curves determined experimentally and readily be used to predict strain-rate effects on the macroscopic responses with the availability of the material parameters at a certain strain rate, which offer new insights into understanding the actual deformation mechanism in amorphous solids. © 2009 American Institute of Physics.published_or_final_versio

Lipoteichoic acid from an Enterococcus faecalis clinical strain promotes TNF-α expression through the NF-κB and p38 MAPK signaling pathways in differentiated THP-1 macrophages

published_or_final_versio