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

Gas Chromatography-Mass Spectrometric Analysis of Essential Oil of Aerial Parts of Glycosmis parviflora (Sims) Little (Rutaceae)

Purpose: To investigate the chemical composition and toxicity of the essential oil of Glycosmis parviflora (Sims) Little aerial parts against root-knot nematode and two grain storage insects (maize weevil and red flour beetle).Methods: Steam distillation of G. parviflora was carried out using Clavenger apparatus in order to extract its volatile oil. Gas chromatography/mass spectrometric (GC/MS) analysis (HP-5MS column) of the essential oil was performed and the toxicity of the oil determined by contact test.Results: A total of 37 components comprising 98.7 % of the essential oil were identified, of which (Z)- caryophyllene (20.6 %), methyl isoeugenol (11.1 %), (Z)-β-ocimene (8.9 %), α-cubebene (6.4 %), nerolidol (5.4 %), aromandendrene (4.9 %) and γ-pyronene (4.7 %) were found to be the major components. The essential oil possessed strong nematicidal activity against M. incognita with an LC50 value of 92.84 μg/ml. The essential oil of G. parviflora exhibited strong contact toxicity against S. zeamais and T. castaneum adults with LD50 values of 41.7 and 22.6 μg/adult,  respectively.Conclusion: The study indicates that the essential oil of G. parviflora aerial parts has a potential for development into a natural insecticide/nematicide for control of nematodes and grain storage insects.Keywords: Glycosmis parviflora, Essential oil, Meloidogyne incognita, Sitophilus zeamais, Triboliumcastaneum, Contact toxicit

Magnetar-like X-ray Bursts from an Anomalous X-ray Pulsar

Anomalous X-ray Pulsars (AXPs) are a class of rare X-ray pulsars whose energy source has been perplexing for some 20 years. Unlike other, better understood X-ray pulsars, AXPs cannot be powered by rotation or by accretion from a binary companion, hence the designation ``anomalous.'' AXP rotational and radiative properties are strikingly similar to those of another class of exotic objects, the Soft Gamma Repeaters (SGRs). However, the defining property of SGRs, namely their low-energy gamma-ray and X-ray bursts, have heretofore not been seen in AXPs. SGRs are thought to be ``magnetars,'' young neutron stars powered by the decay of an ultra-high magnetic field. The suggestion that AXPs are magnetars has been controversial. Here we report the discovery, from the direction of AXP 1E 1048-5937, of two X-ray bursts that have many properties similar to those of SGR bursts. These events imply a close relationship between AXPs and SGRs, with both being magnetars.Comment: 14 pages, 2 figures, accepted for publication in Nature. Note: The content of this paper is embargoed until 1900 hrs London time / 1400 US Eastern Time on Sept 1

Mimetic-enzyme fluorescence immunoassay using a thermal phase separating polymer

Poly-N-isopropylacrylamide (PNIP), a water-soluble, thermally precipitated synthetic polymer, has been conjugated together with a monoclonal antibody and utilized as a novel separation method for an immunoassay. PNIP precipitates out of water above a critical temperature of 31 degrees C, enabling a polymer-bound immune complex to be separated from the solution. These characteristics were used to develop a novel polymer-mimetic enzyme immunoassay method for determination of alpha-1-fetoprotein (AFP) with hemin as a labeling reagent to catalyze the reaction of p-hydroxyphenyl acetic acid (HPA) and hydrogen peroxide in alkaline medium. After a one-step competitive immunoreaction, the polymer-antibody-antigen-hemin conjugate moiety was determined by coupling the fluorogenic reaction of HPA and hydrogen peroxide, The calibration graph for AFP was linear over the range of 0-380 ng cm(-3) with a detection limit of 1.0 ng cm(-3). This method combines some advantages of both homogeneous and heterogeneous immunoassays, and has been applied to determine AFP in human blood serum with satisfactory results

Clinical significance and therapeutic value of glutathione peroxidase 3 (GPx3) in hepatocellular carcinoma

AIMS: We aimed to investigate the clinical significance of GPx3 in hepatocellular carcinoma (HCC) and to characterize its tumor suppressive role. METHODS: HCC patients (113) who underwent hepatectomy were recruited to examine the clinical relevance of GPx3. The tumor suppressive role of GPx3 was studied by administration of recombinant GPx3 (rGPx3) or over-expression of GPx3 in HCC cells in vitro and in vivo. The therapeutic value of GPx3 for HCC was further investigated using human induced pluripotent stem cell derived mesenchymal stem cells (hiPSC-MSCs) as its delivery vehicle. RESULTS: Down-regulation of GPx3 significantly correlated with advanced tumor stage (P = 0.024), venous infiltration (P = 0.043) and poor overall survival (P = 0.007) after hepatectomy. Lower plasma GPx3 in HCC patients was significantly associated with larger tumor size (P = 0.011), more tumor nodules (P = 0.032) and higher recurrence (P = 0.016). Over-expression of GPx3 or administration of rGPx3 significantly inhibited proliferation and invasiveness of HCC cells in vitro and in vivo. Tumor suppressive activity of GPx3 was mediated through Erk-NFκB-SIP1 pathway. GPx3 could be delivered by hiPSC-MSCs into the tumor and exhibited tumor suppressive activity in vivo. CONCLUSIONS: GPx3 is a tumor suppressor gene in HCC and may possess prognostic and therapeutic value for HCC patients.published_or_final_versio

Two populations of X-ray pulsars produced by two types of supernovae

Two types of supernova are thought to produce the overwhelming majority of neutron stars in the Universe. The first type, iron-core collapse supernovae, occurs when a high-mass star develops a degenerate iron core that exceeds the Chandrasekhar limit. The second type, electron-capture supernovae, is associated with the collapse of a lower-mass oxygen-neon-magnesium core as it loses pressure support owing to the sudden capture of electrons by neon and/or magnesium nuclei. It has hitherto been impossible to identify the two distinct families of neutron stars produced in these formation channels. Here we report that a large, well-known class of neutron-star-hosting X-ray pulsars is actually composed of two distinct sub-populations with different characteristic spin periods, orbital periods and orbital eccentricities. This class, the Be/X-ray binaries, contains neutron stars that accrete material from a more massive companion star. The two sub-populations are most probably associated with the two distinct types of neutron-star-forming supernovae, with electron-capture supernovae preferentially producing system with short spin period, short orbital periods and low eccentricity. Intriguingly, the split between the two sub-populations is clearest in the distribution of the logarithm of spin period, a result that had not been predicted and which still remains to be explaine

High energy emission from microquasars

The microquasar phenomenon is associated with the production of jets by X-ray binaries and, as such, may be associated with the majority of such systems. In this chapter we briefly outline the associations, definite, probable, possible, and speculative, between such jets and X-ray, gamma-ray and particle emission.Comment: Contributing chapter to the book Cosmic Gamma-Ray Sources, K.S. Cheng and G.E. Romero (eds.), to be published by Kluwer Academic Publishers, Dordrecht, 2004. (19 pages

High-mass X-ray binaries and OB-runaway stars

High-mass X-ray binaries (HMXBs) represent an important phase in the evolution of massive binary systems. HMXBs provide unique diagnostics to test massive-star evolution, to probe the physics of radiation-driven winds, to study the process of mass accretion, and to measure fundamental parameters of compact objects. As a consequence of the supernova explosion that produced the neutron star (or black hole) in these systems, HMXBs have high space velocities and thus are runaways. Alternatively, OB-runaway stars can be ejected from a cluster through dynamical interactions. Observations obtained with the Hipparcos satellite indicate that both scenarios are at work. Only for a minority of the OB runaways (and HMXBs) a wind bow shock has been detected. This might be explained by the varying local conditions of the interstellar medium.Comment: 15 pages, latex (sty file included) with 5 embedded figures (one in jpg format), to appear in Proc. "Influence of binaries on stellar population studies", Eds. Vanbeveren, Van Rensberge

Autonomous indoor wayfinding for individuals with cognitive impairments

<p>Abstract</p> <p>Background</p> <p>A challenge to individuals with cognitive impairments in wayfinding is how to remain oriented, recall routines, and travel in unfamiliar areas in a way relying on limited cognitive capacity. While people without disabilities often use maps or written directions as navigation tools or for remaining oriented, this cognitively-impaired population is very sensitive to issues of abstraction (e.g. icons on maps or signage) and presents the designer with a challenge to tailor navigation information specific to each user and context.</p> <p>Methods</p> <p>This paper describes an approach to providing distributed cognition support of travel guidance for persons with cognitive disabilities. A solution is proposed based on passive near-field RFID tags and scanning PDAs. A prototype is built and tested in field experiments with real subjects. The unique strength of the system is the ability to provide unique-to-the-user prompts that are triggered by context. The key to the approach is to spread the context awareness across the system, with the context being flagged by the RFID tags and the appropriate response being evoked by displaying the appropriate path guidance images indexed by the intersection of specific end-user and context ID embedded in RFID tags.</p> <p>Results</p> <p>We found that passive RFIDs generally served as good context for triggering navigation prompts, although individual differences in effectiveness varied. The results of controlled experiments provided more evidence with regard to applicabilities of the proposed autonomous indoor wayfinding method.</p> <p>Conclusions</p> <p>Our findings suggest that the ability to adapt indoor wayfinding devices for appropriate timing of directions and standing orientation will be particularly important.</p