391 research outputs found

    HOW KNOWLEDGE MANAGEMENT INTENTION INFLUENCED BY ORGANIZATIONAL CULTURE AND KNOWLEDGE MANAGEMENT CULTURE

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    In the current knowledge economy era, knowledge has become an organization’s primary resource due to the fact that an organization is an extension of an information society. Therefore, firms that are able to effectively manage their knowledge resources can expect to reap a wide range of benefits. Due to the diversity of organizational culture (which include results-oriented, tightly controlled, job-oriented, closed system, solidarity, sociability and need for achievement), a significant issue is the way organizational culture impacts on KM intention in the KM process through the mediation of KM culture. Indeed, strong culture has a direct impact on KM culture and KM intention. This paper details our study findings, which indicate that while results-oriented, solidarity, sociability and strong cultures have significant positive effects on an organization’s ability to foster a KM culture in the KM process, a job-oriented culture has a significant negative effect. Moreover, both KM culture and strong culture have positive direct effects on an individual’s intention to manage knowledge. Also discussed in this paper are the implications of the study and its contribution to research and management practice

    High-Resolution Spectroscopy of Bonding in a Novel BeP2N4 Compound

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    The recently discovered compound BeP2N4 that crystallizes in the phenakite-type structure has potential application as a high strength optoelectronic material. Therefore, it is important to analyze experimentally the electronic structure, which was done in the present work by monochromated electron energy-loss spectroscopy. The detection of Be is challenging due to its low atomic number and easy removal under electron bombardment. We were able to determine the bonding behavior and coordination of the individual atomic species including Be. This is evident from a good agreement between experimental electron energy-loss near-edge structures of the Be-K-, P-L2,3-, and N-K-edges and density functional theory calculations

    Discovery of anthelmintic drug targets and drugs using chokepoints in nematode metabolic pathways

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    Parasitic roundworm infections plague more than 2 billion people (1/3 of humanity) and cause drastic losses in crops and livestock. New anthelmintic drugs are urgently needed as new drug resistance and environmental concerns arise. A "chokepoint reaction" is defined as a reaction that either consumes a unique substrate or produces a unique product. A chokepoint analysis provides a systematic method of identifying novel potential drug targets. Chokepoint enzymes were identified in the genomes of 10 nematode species, and the intersection and union of all chokepoint enzymes were found. By studying and experimentally testing available compounds known to target proteins orthologous to nematode chokepoint proteins in public databases, this study uncovers features of chokepoints that make them successful drug targets. Chemogenomic screening was performed on drug-like compounds from public drug databases to find existing compounds that target homologs of nematode chokepoints. The compounds were prioritized based on chemical properties frequently found in successful drugs and were experimentally tested using Caenorhabditis elegans. Several drugs that are already known anthelmintic drugs and novel candidate targets were identified. Seven of the compounds were tested in Caenorhabditis elegans and three yielded a detrimental phenotype. One of these three drug-like compounds, Perhexiline, also yielded a deleterious effect in Haemonchus contortus and Onchocerca lienalis, two nematodes with divergent forms of parasitism. Perhexiline, known to affect the fatty acid oxidation pathway in mammals, caused a reduction in oxygen consumption rates in C. elegans and genome-wide gene expression profiles provided an additional confirmation of its mode of action. Computational modeling of Perhexiline and its target provided structural insights regarding its binding mode and specificity. Our lists of prioritized drug targets and drug-like compounds have potential to expedite the discovery of new anthelmintic drugs with broad-spectrum efficacy

    Transport of Sputtered Carbon During Ground-Based Life Testing of Ion Thrusters

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    High voltage, high power electron bombardment ion thrusters needed for deep space missions will be required to be operated for long durations in space as well as during ground laboratory life testing. Carbon based ion optics are being considered for such thrusters. The sputter deposition of carbon and arc vaporized carbon flakes from long duration operation of ion thrusters can result in deposition on insulating surfaces, causing them to become conducting. Because the sticking coefficient is less than one, secondary deposition needs to be considered to assure that shorting of critical components does not occur. The sticking coefficient for sputtered carbon and arc vaporized carbon is measured as well as directional ejection distribution data for carbon that does not stick upon first impact

    Analysis of terahertz generation via nanostructure enhanced plasmonic excitations

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    This is the published version. Copyright © 2009 American Institute of PhysicsIn this paper, we conduct a quantitative study on the physical mechanism of electrons dynamics near the nanostructured metalfilmsurfaces, as well as the efficiency of generated terahertz radiation associated with different types of nanostructures. The simulation results show that although the oscillating motion of emitted electrons outside the metal surface may affect the terahertz generation efficiency to some extent, this efficiency is predominantly determined by the electric field magnitude inside the metalfilm associated with nanostructure enhanced plasmonic excitations. Due to the field enhancement effect of the nanostructure, an appropriately designed nanostructured surface could greatly enhance the strength of generated terahertz signal via the increased nonlinear interactions between the light and the nanostructures

    Pulmonary IL- 33 orchestrates innate immune cells to mediate respiratory syncytial virus- evoked airway hyperreactivity and eosinophilia

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    BackgroundRespiratory syncytial virus (RSV) infection is epidemiologically linked to asthma. During RSV infection, IL- 33 is elevated and promotes immune cell activation, leading to the development of asthma. However, which immune cells are responsible for triggering airway hyperreactivity (AHR), inflammation and eosinophilia remained to be clarified. We aimed to elucidate the individual roles of IL- 33- activated innate immune cells, including ILC2s and ST2+ myeloid cells, in RSV infection- triggered pathophysiology.MethodsThe role of IL- 33/ILC2 axis in RSV- induced AHR inflammation and eosinophilia were evaluated in the IL- 33- deficient and YetCre- 13 Rosa- DTA mice. Myeloid- specific, IL- 33- deficient or ST2- deficient mice were employed to examine the role of IL- 33 and ST2 signaling in myeloid cells.ResultsWe found that IL- 33- activated ILC2s were crucial for the development of AHR and airway inflammation, during RSV infection. ILC2- derived IL- 13 was sufficient for RSV- driven AHR, since reconstitution of wild- type ILC2 rescued RSV- driven AHR in IL- 13- deficient mice. Meanwhile, myeloid cell- derived IL- 33 was required for airway inflammation, ST2+ myeloid cells contributed to exacerbation of airway inflammation, suggesting the importance of IL- 33 signaling in these cells. Local and peripheral eosinophilia is linked to both ILC2 and myeloid IL- 33 signaling.ConclusionsThis study highlights the importance of IL- 33- activated ILC2s in mediating RSV- triggered AHR and eosinophilia. In addition, IL- 33 signaling in myeloid cells is crucial for airway inflammation.Respiratory syncytial virus induces ILC2 to produce IL- 5 and IL- 13 through IL- 33, which is crucial for the development of airway hyperreactivity and airway inflammation. Myeloid cell- derived IL- 33 and suppression of tumorigenicity 2- positive myeloid cells contribute to cytokine production and cellular inflammation in airway. Both ILC2 and myeloid cell IL- 33 signaling contribute to local and peripheral eosinophilia.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154896/1/all14091.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154896/2/all14091-sup-0001-Supinfo.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154896/3/all14091_am.pd

    Detection of concealed and buried chemicals by using multifrequency excitations

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    This is the published version. Copyright © 2010 American Institute of PhysicsIn this paper, we present a new type of concealed and buried chemical detection system by stimulating and enhancing spectroscopic signatures with multifrequency excitations, which includes a low frequency gradient dcelectric field, a high frequency microwave field, and higher frequency infrared (IR) radiations. Each excitation frequency plays a unique role. The microwave, which can penetrate into the underground and/or pass through the dielectric covers with low attenuation, could effectively transform its energy into the concealed and buried chemicals and increases its evaporation rate from the sample source. Subsequently, a gradient dcelectric field, generated by a Van De Graaff generator, not only serves as a vapor accelerator for efficiently expediting the transportation process of the vapor release from the concealed and buried chemicals but also acts as a vapor concentrator for increasing the chemical concentrations in the detection area, which enables the trace level chemical detection. Finally, the stimulated and enhanced vapors on the surface are detected by the IR spectroscopic fingerprints. Our theoretical and experimental results demonstrate that more than sixfold increase in detection signal can be achieved by using this proposed technology. The proposed technology can also be used for standoff detection of concealed and buried chemicals by adding the remote IR and/or thermal spectroscopic and imaging detection systems

    Cell-intrinsic lysosomal lipolysis is essential for macrophage alternative activation

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    Alternative (M2) macrophage activation driven through interleukin 4 receptor α (IL-4Rα) is important for immunity to parasites, wound healing, the prevention of atherosclerosis and metabolic homeostasis. M2 polarization is dependent on fatty acid oxidation (FAO), but the source of fatty acids to support this metabolic program has not been clear. We show that the uptake of triacylglycerol substrates via CD36 and their subsequent lipolysis by lysosomal acid lipase (LAL) was important for the engagement of elevated oxidative phosphorylation (OXPHOS), enhanced spare respiratory capacity (SRC), prolonged survival and expression of genes that together define M2 activation. Inhibition of lipolysis suppressed M2 activation during infection with a parasitic helminth, and blocked protective responses against this pathogen. Our findings delineate a critical role for cell-intrinsic lysosomal lipolysis in M2 activation

    Distinct and predictive chromatin signatures of transcriptional promoters and enhancers in the human genome.

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    Eukaryotic gene transcription is accompanied by acetylation and methylation of nucleosomes near promoters, but the locations and roles of histone modifications elsewhere in the genome remain unclear. We determined the chromatin modification states in high resolution along 30 Mb of the human genome and found that active promoters are marked by trimethylation of Lys4 of histone H3 (H3K4), whereas enhancers are marked by monomethylation, but not trimethylation, of H3K4. We developed computational algorithms using these distinct chromatin signatures to identify new regulatory elements, predicting over 200 promoters and 400 enhancers within the 30-Mb region. This approach accurately predicted the location and function of independently identified regulatory elements with high sensitivity and specificity and uncovered a novel functional enhancer for the carnitine transporter SLC22A5 (OCTN2). Our results give insight into the connections between chromatin modifications and transcriptional regulatory activity and provide a new tool for the functional annotation of the human genome. Activation of eukaryotic gene transcription involves the coordination of a multitude of transcription factors and cofactors on regulatory DNA sequences such as promoters and enhancers and on the chromatin structure containing these elements 1-3 . Promoters are located at the 5Âą ends of genes immediately surrounding the transcriptional start site (TSS) and serve as the point of assembly of the transcriptional machinery and initiation of transcription 4 . Enhancers contribute to the activation of their target genes from positions upstream, downstream or within a target or neighboring gene Recent investigations using chromatin immunoprecipitation (ChIP) and microarray (ChIP-chip) experiments have described the chromatin architecture of transcriptional promoters in yeast, fly and mammalian systems 9 . In a manner largely conserved across species, active promoters are marked by acetylation of various residues of histones H3 and H4 and methylation of H3K4, particularly trimethylation of this residue. Nucleosome depletion is also a general characteristic of active promoters in yeast and flies, although this feature remains to be thoroughly examined in mammalian systems. Although some studies suggest that distal regulatory elements like enhancers may be marked by similar histone modification patterns 10-13 , the distinguishing chromatin features of promoters and enhancers have yet to be determined, hindering our understanding of a predictive histone code for different classes of regulatory elements. Here, we present high-resolution maps of multiple histone modifications and transcriptional regulators in 30 Mb of the human genome, demonstrating that active promoters and enhancers are associated with distinct chromatin signatures that can be used to predict these regulatory elements in the human genome. RESULTS Chromatin architecture and transcription factor localization We performed ChIP-chip analysis 14 to determine the chromatin architecture along 44 human loci selected by the ENCODE consortium as common targets for genomic analysis 15 , totaling 30 Mb
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