204 research outputs found

    Digital information and the 'privatisation of knowledge'

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    Purpose of this paper: To point out that past models of information ownership may not carry over to the age of digital information. The fact that public ownership of information (for example, by means of national and public library collections) created social benefits in the past does not mean that a greater degree of private sector involvement in information provision in the knowledge society of today is synonymous with an abandonment of past ideals of social information provision. Design/methodology/approach: A brief review of recent issues in digital preservation and national electronic heritage management, with an examination of the public/private sector characteristics of each issue. Findings: Private companies and philanthropic endeavours focussing on the business of digital information provision have done some things - which in the past we have associated with the public domain - remarkably well. It is probably fair to say that this has occurred against the pattern of expectation of the library profession. Research limitations/Implications:The premise of this paper is that LIS research aimed at predicting future patterns of problem solving in information work should avoid the narrow use of patterns of public-private relationships inherited from a previous, print-based information order. Practical implications: This paper suggests practical ways in which the library and information profession can improve digital library services by looking to form creative partnerships with private sector problem solvers. What is original/value of the paper? This paper argues that the LIS profession should not take a doctrinaire approach to commercial company involvement in 'our' information world. Librarians should facilitate collaboration between all parties, both public and private, to create original solutions to contemporary information provision problems. In this way we can help create pragmatic, non-doctrinaire solutions that really do work for the citizens of our contemporary information society

    Quantitative mass spectrometry imaging of emtricitabine in cervical tissue model using infrared matrix-assisted laser desorption electrospray ionization

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    A quantitative mass spectrometry imaging (QMSI) technique using infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) is demonstrated for the antiretroviral (ARV) drug emtricitabine in incubated human cervical tissue. Method development of the QMSI technique leads to a gain in sensitivity and removal of interferences for several ARV drugs. Analyte response was significantly improved by a detailed evaluation of several cationization agents. Increased sensitivity and removal of an isobaric interference was demonstrated with sodium chloride in the electrospray solvent. Voxel-to-voxel variability was improved for the MSI experiments by normalizing analyte abundance to a uniformly applied compound with similar characteristics to the drug of interest. Finally, emtricitabine was quantified in tissue with a calibration curve generated from the stable isotope-labeled analog of emtricitabine followed by cross-validation using liquid chromatography tandem mass spectrometry (LC-MS/MS). The quantitative IR-MALDESI analysis proved to be reproducible with an emtricitabine concentration of 17.2±1.8 μg/gtissue. This amount corresponds to the detection of 7 fmol/voxel in the IR-MALDESI QMSI experiment. Adjacent tissue slices were analyzed using LC-MS/MS which resulted in an emtricitabine concentration of 28.4±2.8 μg/gtissue

    Mapping Antiretroviral Drugs in Tissue by IR-MALDESI MSI Coupled to the Q Exactive and Comparison with LC-MS/MS SRM Assay

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    This work describes the coupling of the IR-MALDESI imaging source with the Q Exactive mass spectrometer. IR-MALDESI MSI was used to elucidate the spatial distribution of several HIV drugs in cervical tissues that had been incubated in either a low or high concentration. Serial sections to those analyzed by IR-MALDESI MSI were homogenized and analyzed by LC-MS/MS to quantify the amount of each drug present in the tissue. By comparing the two techniques, an agreement between the average intensities from the imaging experiment with the absolute quantities for each drug was observed. This correlation between these two techniques serves as a prerequisite to quantitative IR-MALDESI MSI. In addition, a targeted MS2 imaging experiment was also conducted to demonstrate the capabilities of the Q Exactive and to highlight the added selectivity that can be obtained with SRM or MRM imaging experiments

    Mass Spectrometry Imaging Reveals Heterogeneous Efavirenz Distribution within Putative HIV Reservoirs

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    ABSTRACT Persistent HIV replication within active viral reservoirs may be caused by inadequate antiretroviral penetration. Here, we used mass spectrometry imaging with infrared matrix-assisted laser desorption–electrospray ionization to quantify the distribution of efavirenz within tissues from a macaque dosed orally to a steady state. Intratissue efavirenz distribution was heterogeneous, with the drug concentrating in the lamina propria of the colon, the primary follicles of lymph nodes, and the brain gray matter. These are the first imaging data of an antiretroviral drug in active viral reservoirs
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