419 research outputs found

    A Series of 4- and 5-Coordinate Ni(II) Complexes: Synthesis, Characterization, Spectroscopic, and DFT Studies

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    A series of four- and five-coordinate Ni(II) complexes CztBu(PyriPr)2NiX (1–3 and 1·THF–3·THF), where X = Cl, Br, and I, were synthesized and fully characterized by NMR and UV–vis spectroscopy, X-ray crystallography, cyclic voltammetry, and density functional theory calculations. The solid-state structures of 1–3 reveal rare examples of seesaw Ni(II) complexes. In solution, 1–3 bind reversibly to a THF molecule to form five-coordinate adducts. The electronic transitions in the visible region (630–680 nm), attributed to LMCT bands, for 1 → 3 exhibit a bathochromic shift. The thermochromic tendency of the five-coordinate complexes implies the loss of THF coordination at elevated temperatures. Finally, the electronic properties of all Ni(II) complexes were studied by time-dependent density functional theory calculations to characterize the nature of the excited states

    Gender and Tahrir Square: contesting the state and imagining a new nation

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    This article argues that the concepts of ‘State’ and ‘Nation’ should be treated as separate from one another, hence, more than one image of the nation is possible at one given time. During the early days of the January 2011 Egyptian revolution, a contestation emerged between Mubarak’s state and the protesters in Tahrir Square over the image and notion of the Egyptian nation. Both the state and the protesters attempted to exclude one another from their respective discourse of the Egyptian nation. While reflecting back on a number of women’s voices who joined the early days of the Tahrir Square protests and using qualitative fieldwork interviews with Cairo-based feminist and political activists, this article points to the complexity of a newly forged image of Egyptian nationhood. In Tahrir Square, this image appeared to be largely framed within gendered criteria where notions of manhood and hyper visible gender equality were intrinsically linked to the broader objective of removing Mubarak and his regime. This raises the question of whether new gender paradigms of equality can continue to exist beyond Tahrir Square’s imagination of a ‘new’ nation

    Report of the expert meeting on food safety for seaweed – Current status and future perspectives

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    The world production of marine macroalgae, or seaweed, has more than tripled since the turn of the millennium, increasing from 10.6 million tonnes in 2000 to 32.4 million tonnes in 2018. Increased cultivation and utilization of seaweed are expected to be important pillars of sustainable food security and a robust aquatic economy in the coming years. It is important, therefore, to consider the food safety implications of (increased) seaweed use for food. Many factors can affect the presence of hazards in seaweed, including: the type of seaweed, its physiology, the season in which it is produced, production waters, harvesting methods and processing. Several hazards such as heavy metals and marine biotoxins have been reported to be (potentially) associated with seaweed. However, legislation and guidance documents on the production and utilization of seaweed are generally still lacking. FAO and the World Health Organization (WHO) have therefore developed this report to identify food safety hazards (microbiological, chemical and physical) linked to the consumption of seaweed and aquatic plants. The present analysis could therefore provide a basis for undertaking further work in this area. Moreover, both FAO and WHO believe that there would be a value in developing relevant Codex guidance on this subject.publishedVersio

    Report of the expert meeting on food safety for seaweed – Current status and future perspectives

    Get PDF
    The world production of marine macroalgae, or seaweed, has more than tripled since the turn of the millennium, increasing from 10.6 million tonnes in 2000 to 32.4 million tonnes in 2018. Increased cultivation and utilization of seaweed are expected to be important pillars of sustainable food security and a robust aquatic economy in the coming years. It is important, therefore, to consider the food safety implications of (increased) seaweed use for food. Many factors can affect the presence of hazards in seaweed, including: the type of seaweed, its physiology, the season in which it is produced, production waters, harvesting methods and processing. Several hazards such as heavy metals and marine biotoxins have been reported to be (potentially) associated with seaweed. However, legislation and guidance documents on the production and utilization of seaweed are generally still lacking. FAO and the World Health Organization (WHO) have therefore developed this report to identify food safety hazards (microbiological, chemical and physical) linked to the consumption of seaweed and aquatic plants. The present analysis could therefore provide a basis for undertaking further work in this area. Moreover, both FAO and WHO believe that there would be a value in developing relevant Codex guidance on this subject

    Screening for C3 Deficiency in Newborns Using Microarrays

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    BACKGROUND: Dried blood spot samples (DBSS) from newborns are widely used in neonatal screening for selected metabolic diseases and diagnostic possibilities for additional disorders are continuously being evaluated. Primary immunodeficiency disorders comprise a group of more than one hundred diseases, several of which are fatal early in life. Yet, a majority of the patients are not diagnosed due to lack of high-throughput screening methods. METHODOLOGY/PRINCIPAL FINDINGS: We have previously developed a system using reverse phase protein microarrays for analysis of IgA levels in serum samples. In this study, we extended the applicability of the method to include determination of complement component C3 levels in eluates from DBSS collected at birth. Normal levels of C3 were readily detected in 269 DBSS from healthy newborns, while no C3 was detected in sera and DBSS from C3 deficient patients. CONCLUSIONS/SIGNIFICANCE: The findings suggest that patients with deficiencies of specific serum proteins can be identified by analysis of DBSS using reverse phase protein microarrays.QC 20120213</p

    Order versus Disorder: in vivo bone formation within osteoconductive scaffolds

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    In modern biomaterial design the generation of an environment mimicking some of the extracellular matrix features is envisaged to support molecular cross-talk between cells and scaffolds during tissue formation/remodeling. In bone substitutes chemical biomimesis has been particularly exploited; conversely, the relevance of pre-determined scaffold architecture for regenerated bone outputs is still unclear. Thus we aimed to demonstrate that a different organization of collagen fibers within newly formed bone under unloading conditions can be generated by differently architectured scaffolds. An ordered and confined geometry of hydroxyapatite foams concentrated collagen fibers within the pores, and triggered their self-assembly in a cholesteric-banded pattern, resulting in compact lamellar bone. Conversely, when progenitor cells were loaded onto nanofibrous collagen-based sponges, new collagen fibers were distributed in a nematic phase, resulting mostly in woven isotropic bone. Thus specific biomaterial design relevantly contributes to properly drive collagen fibers assembly to target bone regeneration

    Intrinsic NLRP3 inflammasome activity is critical for normal adaptive immunity via regulation of IFN-Îł in CD4+ T cells

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    The NLRP3 inflammasome controls interleukin-1b maturation in antigen-presenting cells, but a direct role for NLRP3 in human adaptive immune cells has not been described.We found that the NLRP3 inflammasome assembles in human CD4+ Tcells and initiates caspase-1–dependent interleukin-1b secretion, thereby promoting interferon-g production and T helper 1 (TH1) differentiation in an autocrine fashion. NLRP3 assembly requires intracellular C5 activation and stimulation of C5a receptor 1 (C5aR1), which is negatively regulated by surface-expressed C5aR2. Aberrant NLRP3 activity in Tcells affects inflammatory responses in human autoinflammatory disease and in mouse models of inflammation and infection. Our results demonstrate that NLRP3 inflammasome activity is not confined to “innate immune cells” but is an integral component of normal adaptive TH1 responses
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