16,774 research outputs found
The CO and CO Absorption Bands as Tracers of the Thermal History of Interstellar Icy Grain Mantles
Analyses of infrared signatures of CO in water dominated ices in the ISM
can give information on the physical state of CO in icy grains and on the
thermal history of the ices themselves. In many sources, CO was found in
the `pure' crystalline form, as signatured by the splitting in the bending mode
absorption profile. To a large extent, pure CO is likely to have formed
from segregation of CO from a CO:HO mixture during thermal
processing. Previous laboratory studies quantified the temperature dependence
of segregation, but no systematic measurement of the concentration dependence
of segregation is available. In this study, we measured both the temperature
dependence and concentration dependence of CO segregation in CO:HO
mixtures, and found that no pure crystalline CO forms if the CO:HO
ratio is less than 23%. Therefore the segregation of CO is not always a
good thermal tracer of the ice mantle. We found that the position and width of
the broad component of the asymmetric stretching vibrational mode of
CO change linearly with the temperature of CO:HO mixtures,
but are insensitive to the concentration of CO. We recommend using this
mode, which will be observable towards low mass protostellar envelopes and
dense clouds with the James Webb Space Telescope, to trace the thermal history
of the ice mantle, especially when segregated CO is unavailable. We used
the laboratory measured CO profile to analyze the ISO-SWS
observations of ice mantles towards Young Stellar Objects, and the
astrophysical implications are discussed.Comment: 11 pages, 12 figures, ApJ accepte
Spatial imaging of Zn and other elements in Huanglongbing-affected grapefruit by synchrotron-based micro X-ray fluorescence investigation
Huanglongbing (HLB) is a highly destructive, fast-spreading disease of citrus, causing substantial economic losses to the citrus industry worldwide. Nutrient levels and their cellular distribution patterns in stems and leaves of grapefruit were analysed after graft-inoculation with lemon scions containing 'Candidatus Liberibacter asiaticus' (Las), the heat-tolerant Asian type of the HLB bacterium. After 12 months, affected plants showed typical HLB symptoms and significantly reduced Zn concentrations in leaves. Micro-XRF imaging of Zn and other nutrients showed that preferential localization of Zn to phloem tissues was observed in the stems and leaves collected from healthy grapefruit plants, but was absent from HLB-affected samples. Quantitative analysis by using standard references revealed that Zn concentration in the phloem of veins in healthy leaves was more than 10 times higher than that in HLB-affected leaves. No significant variation was observed in the distribution patterns of other elements such as Ca in stems and leaves of grapefruit plants with or without graft-inoculation of infected lemon scions. These results suggest that reduced phloem transport of Zn is an important factor contributing to HLB-induced Zn deficiency in grapefruit. Our report provides the first in situ, cellular level visualization of elemental variations within the tissues of HLB-affected citrus. © 2014 © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology
Avoid illegal encrypted DRM content sharing with non-transferable re-encryption
Digital rights management (DRM) technology enables valuable electronic media content distribution while preserving content providers' rights and revenues. Traditional DRM system utilizes security techniques to restrict copying of media content or allow only a single copy to be made. However consumers are demanding for the right to make copies for personal use or the right to use content on any device. Several DRM infrastructures have been proposed for secure content sharing. These infrastructures usually require cooperation and participation of both DRM technology providers and content providers; however there is a popular flaw in these schemes: the malicious employees of DRM technology providers can distribute DRM enabled contents to any consumers or make copies of a purchased content accessible to any devices without letting content provider know, thus reducing content providers' benefit. In this paper, we propose a novel DRM infrastructure which is based on a non-transferable re-encryption scheme to solve the above problem inherent in existing DRM infrastructures. In the proposed infrastructure, DRM technology providers and content providers are required to cooperate to make a purchased digital content for a specific device accessible by other different devices, and get extra profit from providing such services. The system preserves DRM technology providers and content providers' security properties while achieving secure and mutual profitable DRM content sharing. Furthermore, we allow content providers to trace the content, and control the content sharing rights. Even when malicious employees in DRM technology providers and DRM agent collude, they cannot re-delegate access rights to any device without permission from content provider, thus preserving content provider's benefit. © 2011 IEEE.published_or_final_versionThe IEEE 13th International Conference on Communication Technology (ICCT 2011), Jinan, China, 25-28 September 2011. In Proceedings of the 13th ICCT, 2011, p. 703-70
The importance of clinically relevant background therapy in cardioprotective studies
Treatment of acute myocardial infarct patients (AMI) includes rapid restoration of coronary blood flow and pharmacological therapy aimed to prevent pain and maintain vessel patency. Many interventions have been investigated to offer additional protection. One such intervention is remote ischaemic conditioning (RIC) involving short-episodes of ischaemia of the arm with a blood pressure cuff, followed by reperfusion to protect the heart organs from subsequent severe ischaemia. However, the recent CONDI2-ERIC-PPCI multicentre study of RIC in STEMI showed no benefit in clinical outcome in low risk patients. It could also be argued that these patients were already in a partially protected state, highlighting the disconnect between animal- and clinical-based outcome studies. To improve potential translatability, we developed an animal model using pharmacological agents similar to those given to patients presenting with an AMI, prior to PPCI. Rats underwent MI on a combined background of an opioid agonist, heparin and a platelet-inhibitor thereby allowing us to assess whether additional cardioprotective strategies had any effect over and above this “cocktail”. We demonstrated that the “background drugs” were protective in their own right, reducing MI from 57.5 ± 3.7% to 37.3 ± 2.9% (n = 11, p < 0.001). On this background of drugs, RIC did not add any further protection (38.0 ± 3.4%). However, using a caspase inhibitor, which acts via a different mechanistic pathway to RIC, we were able to demonstrate additional protection (20.6 ± 3.3%). This concept provides initial evidence to develop models which can be used to evaluate future animal-to-clinical translation in cardioprotective studies
Non-Transferable Proxy Re-Encryption Scheme
SEC8: Selected topics in Information SecurityA proxy re-encryption (PRE) scheme allows a proxy to re-encrypt a ciphertext for Alice (delegator) to a ciphertext for Bob (delegatee) without seeing the underlying plaintext. However, existing PRE schemes generally suffer from at least one of the followings. Some schemes fail to provide the non-transferable property in which the proxy and the delegatee can collude to further delegate the decryption right to anyone. This is the main open problem left for PRE schemes. Other schemes assume the existence of a fully trusted private key generator (PKG) to generate the re-encryption key to be used by the proxy for re-encrypting a given ciphertext for a target delegatee. But this poses two problems in PRE schemes if the PKG is malicious: the PKG in their schemes may decrypt both original ciphertexts and re-encrypted ciphertexts (referred as the key escrow problem); and the PKG can generate reencryption key for arbitrary delegatees without permission from the delegator (we refer to it as the PKG despotism problem). In this paper, we propose the first non-transferable proxy re-encryption scheme which successfully achieves the nontransferable property. We show that the new scheme solved the PKG despotism problem and key escrow problem as well. © 2012 IEEE.published_or_final_versio
Processed meat consumption and Lung function: modification by antioxidants and smoking
This article has supplementary material available from www.erj.ersjournals.com: This study was supported by the Medical Research Council, UK. H. Okubo was supported in part by
fellowship of the Astellas Foundation for Research on Metabolic Disorders, Japan and the Naito Memorial Grant for
Research Abroad from the Naito Foundation, Japan
Small extracellular vesicles secreted from human amniotic fluid mesenchymal stromal cells possess cardioprotective and promigratory potential
Mesenchymal stromal cells (MSCs) exhibit antiapoptotic and proangiogenic functions in models of myocardial infarction which may be mediated by secreted small extracellular vesicles (sEVs). However, MSCs have frequently been harvested from aged or diseased patients, while the isolated sEVs often contain high levels of impurities. Here, we studied the cardioprotective and proangiogenic activities of size-exclusion chromatography-purified sEVs secreted from human foetal amniotic fluid stem cells (SS-hAFSCs), possessing superior functional potential to that of adult MSCs. We demonstrated for the first time that highly pure (up to 1.7 × 1010 particles/µg protein) and thoroughly characterised SS-hAFSC sEVs protect rat hearts from ischaemia–reperfusion injury in vivo when administered intravenously prior to reperfusion (38 ± 9% infarct size reduction, p < 0.05). SS-hAFSC sEVs did not protect isolated primary cardiomyocytes in models of simulated ischaemia–reperfusion injury in vitro, indicative of indirect cardioprotective effects. SS-hAFSC sEVs were not proangiogenic in vitro, although they markedly stimulated endothelial cell migration. Additionally, sEVs were entirely responsible for the promigratory effects of the medium conditioned by SS-hAFSC. Mechanistically, sEV-induced chemotaxis involved phosphatidylinositol 3-kinase (PI3K) signalling, as its pharmacological inhibition in treated endothelial cells reduced migration by 54 ± 7% (p < 0.001). Together, these data indicate that SS-hAFSC sEVs have multifactorial beneficial effects in a myocardial infarction setting
Investigating and analyzing the web-based contents on Chinese Shanzhai mobile phones
Chinese Shanzhai mobile phone has had a huge commercial market in China and overseas and was found to be involved in criminal cases. In this paper, a MTK-based Shanzhai phone with private web browser was investigated to extract user's web browsing data in the form of sites visited, received emails, attempted Internet searches and etc. Based on the findings, extracting Internet search conducted and web email received from the binary image was demonstrated. Besides, deleted browsing history can be recovered from snapshots in memory help reconstruct user's browsing activity and timeline analysis.postprintThe 7th International Workshop on Systematic Approaches to Digital Forensic Engineering (IEEE/SADFE 2012), Vancouver, BC., 26-28 September 2012, p. 1297-130
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