Publications by authors named "Lewis E MacKenzie"

The objective of this investigation was to evaluate the influence of micro- and nanoplastic particles composed of polyethylene terephthalate (PET), a significant contributor to plastic pollution, on human brain vascular pericytes. Specifically, we delved into their impact on mitochondrial functionality, oxidative stress, and the expression of genes associated with oxidative stress, ferroptosis and mitochondrial functions. Our findings demonstrate that the exposure of a monoculture of human brain vascular pericytes to PET particles in vitro at a concentration of 50 μg/ml for a duration of 3, 6 and 10 days did not elicit oxidative stress.

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Polyvinylpyrrolidone (PVP) can be used to produce upconversion nanoparticles (UCNPs) in an advantageous manner, i.e. at modest temperatures in open-to-air conditions with simple hotplate and flask apparatus.

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An RNA-based coordination polymer is formed by the aqueous reaction of Cu ions with the thionucleoside enantiomer (-)6-thioguanosine, (6tGH). The resulting polymer, [Cu(μ-S-thioG)]1, has a one-dimensional structure based on a [Cu-S] core and undergoes extensive hierarchical self-assembly transforming from oligomeric chains → rod → cable → bundle through which a fibrous gel forms, that undergoes syneresis to form a self-supporting mass. The assembly involves the formation of helical cables/bundles and, in combination with the intrinsic photoemission of the polymer, results in the material exhibiting circularly polarised luminescence (CPL).

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The aqueous equimolar reaction of Ag(i) ions with the thionucleoside enantiomer (-)6-thioguanosine, ((-)6tGH), yields a one-dimensional coordination polymer {Ag(-)tG} , the self-assembly of which generates left-handed helical chains. The resulting helicity induces an enhanced chiro-optical response compared to the parent ligand. DFT calculations indicate that this enhancement is due to delocalisation of the excited state along the helical chains, with 7 units being required to converge the calculated CD spectra.

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Cubic (α-phase) NaYF:Yb,Er upconversion nanoparticles (UCNPs) are uniquely suited to biophotonics and biosensing applications due to their near-infrared excitation and visible red emission ( approx. 660 nm), enabling detection via thick overlying tissue with no bio-autofluorescence. However, UCNP synthesis typically requires high temperatures in combination with either high pressure reaction vessels or an inert atmosphere.

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Controlled formation of desired lanthanide supramolecular complexes is challenging because of the difficulties in predicting coordination geometry, as well as a labile coordination number. Herein, we explore the effect of ionic radii and linker length on supramolecular species formation. A helicate-to-tetrahedron transformation occurred between [LnL1] and [LnL1] (Ln = La, Sm, Eu, Gd, Tb and Lu).

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Authenticating products and documents with security inks is vital to global commerce, security and health. Lanthanide complexes are widely used in luminescent security inks owing to their unique and robust photophysical properties. Lanthanide complexes can also be engineered to undergo circularly polarized luminescence (CPL), which encodes chiral molecular fingerprints in luminescence spectra that cannot be decoded by conventional optical measurements.

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Chirality is ubiquitous within biological systems where many of the roles and functions are still undetermined. Given this, there is a clear need to design and develop sensitive chiral optical probes that can function within a biological setting. Here we report the design and synthesis of magnetically responsive Circularly Polarized Luminescence (CPL) complexes displaying exceptional photophysical properties (quantum yield up to 31 % and |g | up to 0.

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Circular polarisation luminescence (CPL) emission spectroscopy is a powerful tool for probing the fundamental chiroptical features of optically emissive chiral molecular systems. However, uptake of CPL spectroscopy has been impeded by the limitations of conventional scanning monochromator (SM) CPL spectrometers, which are costly to acquire and maintain, and typically require tens of minutes to acquire a typical CPL spectrum. Here, we demonstrate a design of CPL spectrometer which uses rapid readout solid state (SS) spectrometer detectors and a dual channel optical layout to acquire CPL spectra in as little as 10 milliseconds.

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The enantiomers of [EuL]·3Cl, an analogue of Eu:BPEPC with a lowered energy excitation wavelength, serve as effective reference complexes for the calibration of circularly polarised luminescence (CPL) spectrometers.

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One-step cyclization of a tetraazamacrocycle with 70% yield in a 25-g scale was performed. Its chiral DOTA derivatives, , has ∼93% of TSAP coordination isomer in its Eu(III) and Yb(III) complexes in aqueous solution. exhibits a high relaxivity, making it a promising and efficient MRI contrast agent.

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Since 2004, podcasts have emerged as a decentralized medium for science communication to the global public. However, to date, there have been no large-scale quantitative studies of the production and dissemination of science podcasts. This study identified 952 English language science podcasts available between January and February 2018 and analysed online textual and visual data related to the podcasts and classified and noted key production parameters.

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Upconversion nanoparticles (UCNPs) with sodium yttrium fluoride, NaYF (host lattice) doped with Yb (sensitizer) and Er (activator) were synthesized via hydrothermal route incorporating polyethyleneimine (PEI) for their long-term stability in water. The cationic PEI-modified UCNPs with diameter 20 ± 4 nm showed a zeta potential value of +36.5 mV and showed an intense, visible red luminescence and low-intensity green emission with 976 nm laser excitation.

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Upconversion nanoparticles (UCNPs) are utilized extensively for biomedical imaging, sensing, and therapeutic applications, yet the molecular weight of UCNPs has not previously been reported. Herein, we present a theory based upon the crystal structure of UCNPs to estimate the molecular weight of UCNPs: enabling insight into UCNP molecular weight for the first time. We estimate the theoretical molecular weight of various UCNPs reported in the literature, predicting that spherical NaYF4 UCNPs ~ 10 nm in diameter will be ~1 MDa (i.

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Quantification of blood oxygen saturation (SO) in vivo is essential for understanding the pathogenesis of diseases in which hypoxia is thought to play a role, including inflammatory disorders such as multiple sclerosis (MS) and rheumatoid arthritis (RA). We describe a low-cost multispectral microscope and oximetry technique for calibration-free absolute oximetry of surgically exposed blood vessels in vivo. We imaged the vasculature of the dorsal spinal cord in healthy rats, and varied inspired oxygen (FiO) in order to evaluate the sensitivity of the imaging system to changes in SO.

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