970 research outputs found
Effective link operation duration: a new routing metric for mobile ad hoc networks
The dynamic topology of mobile ad hoc networks (MANETs) is caused by node mobility and fading of the wireless link. Link reliability is often measured by the estimated lifetime and the stability of a link. In this paper we propose that the stability of a link can be represented by the time duration in which the two nodes at each end of a link are within each otherâs transmission range and the fading is above an acceptable threshold. A novel routing metric, called effective link operation duration (ELOD), is proposed and implemented into AODV (AODV-ELOD). Simulation results show that proposed AODVELOD outperforms both AODV and the Flow Oriented Routing Protocol (FORP)
Accommodating congestion and fading in mobile ad hoc networks : routing protocol design and optimization
Dynamic increase factor (DIF) for concrete in compression and tension in FE modelling with a local concrete model
Monitoring forest dynamics (1988-2010) in Changting County using time series of remote sensing data
Extraction and identification of the hepatoprotective bio-active components of the root of Actinidia deliciosa
The root of Actinidia deliciosa has been used as traditional drugs in China for a long time. This study therefore aimed at investigating the hepatoprotective bio-active components from the root of A. deliciosa comprehensively and accurately, thus promoting the exploitation and utilization of the whole resource of A. deliciosa. For the purpose of this study, the roots of A. deliciosa were fractionated into various extract fractions with differential polarity solvent. The hepatoprotective activities of various solvent extracts were assessed by examining the effect on carbon tetrachloride (CCl4)-induced hepatotoxicity in rats. The highest hepatoprotective activities fraction was further isolated with column chromatography. The structures of the activities monomers were identified with modern spectrum technology such as infrared (IR), ultraviolet (UV), electron impact mass spectrometry (EI-MS), proton nuclear magnetic resonance (1H-NMR), carbon nuclear magnetic resonance (13C-NMR) and distortionless enhancement by polarization transfer-nuclear magnetic resonance (DEPT-NMR). Of the various extract fractions, the ethyl acetate extract (Fr3) exhibited the highest hepatoprotective activities (p<0.05). When the Fr3 was separated into five fractions by silica gel chromatography, among the five fractions fraction, Fr9 showed the highest yield and the highest hepatoprotective activities. When using Fr9 at a dose of 200 mg/kg to pre- and post-treat the CCl4-induced rat, the activities of alanine transaminase (ALT) decreased by 90.10 and 88.60%, aspartate transaminase (AST) decreased by 80.69 and 79.92% in rat serum, the lipid peroxidation (malondialdehyde (MDA)) decreased by 42.11 and 45.53%, while glutathione (GSH) increased by 114.12 and 147.62% in the rats liver homogenate, respectively as compared with that of the CCl4 control rats. The fraction Fr9 was further separated into five fractions using silica gel chromatography, which were investigated for the main chemical constituents by column chromatography techniques, physico-chemical constants and spectroscopic analysis. Its main chemical constituents were three triterpenoids named 3ÎČ-hydroxy-urs-12-en-28-oic acid (ursolic acid), 2α,3α,23-trihydroxy-urs-12-en-28-oic acid and 2α,3ÎČ,19,23-tetrahydroxy-urs-12-en-28-oic acid. The findings indicate that the high hepatoprotective activity of the fraction of A. deliciosa root is due to its enriched triterpenoid.Key words: Actinidia deliciosa root, carbon tetrachloride (CCl4), hepatoprotective, Chemistry
Lasing- Encoded Microsensor Driven by Interfacial Cavity Resonance Energy Transfer
Microlasers are emerging tools for biomedical applications. In particular, whispering- gallery- mode (WGM) microlasers are promising candidates for sensing at the biointerface owing to their high quality- factor and potential in molecular assays, and intracellular and extracellular detection. However, lasing particles with sensing functionality remain challenging since the overlap between the WGM optical mode and external gain medium is much lower compared to internal gain inside the cavity. To overcome this problem, the concept of Förster resonant energy transfer (FRET) is exploited on WGM droplet microlaser by separating donor and acceptor molecules at the cavity- surface interface. It is first discovered that the interfacial FRET laser not only originates from conventional FRET but utilizes coherent radiative energy transfer (CRET) to excite acceptor molecules by inducing light- harvesting effect near the cavity interface. Simulations and experiments have revealed that the absorption spectrum of individual analyte plays a crucial role in interfacial FRET laser. Distinct lasing spectra can therefore distinguish molecules of different absorption properties upon binding. Finally, detection of small fluorescent molecules and photosynthetic protein is performed. The results presented here not only demonstrate the wide- ranging potential of microlaser external cavity implementation in molecular sensing applications, but also provide comprehensive insights into cavity energy transfer in laser physics.A novel concept is proposed to achieve active lasing- encoded biosensors by taking advantage of light- harvesting effect at the cavity interface, where interfacial molecular lasers based on cavity resonant energy transfer are demonstrated. This work marks a critical step of realizing whispering- gallery- mode (WGM) laser probes for biosensing, opening a new avenue in laser- based molecular sensing.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154969/1/adom201901596-sup-0001-SuppMat.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154969/2/adom201901596_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154969/3/adom201901596.pd
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