12 research outputs found

    Accounting for the Transitions after Entrepreneurial Business Failure: An Emerging Market Perspective

    Get PDF
    This study builds on prior scholarly works on institutions and entrepreneurship by examining the process of transitions and institutional obstacles that force serial entrepreneurs’ shift to operate in the formal or informal sector after entrepreneurial business failures. Using insights from 32 serial entrepreneurs in Ghana, a framework was developed and utilized to explicate how the pull and push motivations for the transition into or persisting with formality or informality after business failure unfolds over time. Our analysis sheds light on the processes and effects of the motivations on the persistently high level of entrepreneurial activities in the informal sector for many emerging economies

    SRM・CRMăźèŠłç‚čă‹ă‚‰è€ƒćŻŸă™ă‚‹ć•†ç€Ÿć–¶æ„­ăźă‚łăƒłăƒ”ăƒ†ăƒłă‚·ăƒŒ

    Get PDF
    Stem cells have captured the imagination of the general public by their potential as new therapeutic tools in the fight against degenerative diseases. This potential is based on their capability for self-renewal and at the same time for producing progenitor cells that will eventually provide the building blocks for tissue and organ regeneration. These processes are carefully orchestrated in the organism by means of a series of molecular cues. An emerging molecule which is responsible for some of these physiological responses is adrenomedullin, a 52-amino acid regulatory peptide which increases proliferation and regulates cell fate of stem cells of different origins. Adrenomedullin binds to specific membrane receptors in stem cells and induces several intracellular pathways such as those involving cAMP, Akt, or MAPK. Regulation of adrenomedullin levels may help in directing the growth and differentiation of stem cells for applications (e.g., cell therapy) both in vitro and in vivo. © 2012 Elsevier Inc.Peer Reviewe

    Adrenomedullin and tumour microenvironment

    Get PDF

    The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

    Get PDF
    INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

    Characterization of Tris (5-amino-1,10-phenanthroline) Ruthenium(II/III) Polymer Films Using Cyclic Voltammetry and Rutherford Backscattering Spectrometry

    No full text
    Platinum electrodes were chemically modified with tris(5-amino-1,10-phenanthroline) ruthenium(II) via electropolymerization. The characterization of the thin films was accomplished with cyclic voltammetry (CV) and Rutherford Backscattering Spectrometry (RBS). Data indicates a strong correlation between the peak currents from the characterization cyclic voltammograms and the number of cycles of electropoly-merization. Rutherford Backscattering Spectrometry showed the same trend, and verified that film thickness is strongly dependent on the concentration of the monomer ruthenium solution. Film thickness was determined from the change in ion beam energy as it passed through the film and was calculated to be 1.0 x 1018 atoms/cm2 – 3.4 x 1018 atoms/cm2, depending upon the number of electropolymerization cycles. The electrodes also showed differences in surface roughness, which were dependent on film thickness
    corecore