Publications by authors named "C Fiona Cullen"

269 Publications

Synthesis and characterisation of thin-film platinum disulfide and platinum sulfide.

Nanoscale 2021 Apr 13;13(15):7403-7411. Epub 2021 Apr 13.

School of Chemistry, Trinity College Dublin, Dublin 2, D02 PN40, Ireland.

Group-10 transition metal dichalcogenides (TMDs) are rising in prominence within the highly innovative field of 2D materials. While PtS has been investigated for potential electronic applications, due to its high charge-carrier mobility and strongly layer-dependent bandgap, it has proven to be one of the more difficult TMDs to synthesise. In contrast to most TMDs, Pt has a significantly more stable monosulfide, the non-layered PtS. The existence of two stable platinum sulfides, sometimes within the same sample, has resulted in much confusion between the materials in the literature. Neither of these Pt sulfides have been thoroughly characterised as-of-yet. Here we utilise time-efficient, scalable methods to synthesise high-quality thin films of both Pt sulfides on a variety of substrates. The competing nature of the sulfides and limited thermal stability of these materials is demonstrated. We report peak-fitted X-ray photoelectron spectra, and Raman spectra using a variety of laser wavelengths, for both materials. This systematic characterisation provides a guide to differentiate between the sulfides using relatively simple methods which is essential to enable future work on these interesting materials.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0nr06197bDOI Listing
April 2021

Oligodendrogenesis and myelination regulate cortical development, plasticity and circuit function.

Semin Cell Dev Biol 2021 Apr 13. Epub 2021 Apr 13.

Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia. Electronic address:

During cortical development and throughout adulthood, oligodendrocytes add myelin internodes to glutamatergic projection neurons and GABAergic inhibitory neurons. In addition to directing node of Ranvier formation, to enable saltatory conduction and influence action potential transit time, oligodendrocytes support axon health by communicating with axons via the periaxonal space and providing metabolic support that is particularly critical for healthy ageing. In this review we outline the timing of oligodendrogenesis in the developing mouse and human cortex and describe the important role that oligodendrocytes play in sustaining and modulating neuronal function. We also provide insight into the known and speculative impact that myelination has on cortical axons and their associated circuits during the developmental critical periods and throughout life, particularly highlighting their life-long role in learning and remembering.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.semcdb.2021.03.017DOI Listing
April 2021

Periaxonal and nodal plasticities modulate action potential conduction in the adult mouse brain.

Cell Rep 2021 Jan;34(3):108641

Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS 7000, Australia. Electronic address:

Central nervous system myelination increases action potential conduction velocity. However, it is unclear how myelination is coordinated to ensure the temporally precise arrival of action potentials and facilitate information processing within cortical and associative circuits. Here, we show that myelin sheaths, supported by mature oligodendrocytes, remain plastic in the adult mouse brain and undergo subtle structural modifications to influence action potential conduction velocity. Repetitive transcranial magnetic stimulation and spatial learning, two stimuli that modify neuronal activity, alter the length of the nodes of Ranvier and the size of the periaxonal space within active brain regions. This change in the axon-glial configuration is independent of oligodendrogenesis and robustly alters action potential conduction velocity. Because aptitude in the spatial learning task was found to correlate with action potential conduction velocity in the fimbria-fornix pathway, modifying the axon-glial configuration may be a mechanism that facilitates learning in the adult mouse brain.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.celrep.2020.108641DOI Listing
January 2021

Health literacy impacts self-management, quality of life and fear of recurrence in head and neck cancer survivors.

J Cancer Surviv 2021 Jan 9. Epub 2021 Jan 9.

School of Psychology, Dublin City University, Dublin, Ireland.

Purpose: Little is known about whether health literacy is associated with affects certain key outcomes in head and neck cancer (HNC) survivors. We investigated (i) the socio-demographic and clinical profile of health literacy and (ii) associations among between health literacy and self-management behaviours, health-related quality of life (HRQL) and fear of recurrence (FoR) in HNC survivors.

Methods: A population-based survey was conducted in Ireland. Health literacy was assessed using a validated single-item question. Socio-demographic, clinical and psychosocial outcome variables (FoR, self-management behaviours, HRQL) were collected. Multivariable linear regression was performed to estimate associations between health literacy and each psychosocial outcome.

Results: Three hundred ninety-five (50%) individuals responded to the survey. Inadequate health literacy was evident among 47% of the sample. In adjusted models, HNC survivors with inadequate health literacy had significantly lower levels of self-management behaviours in the domains of health-directed behaviour, positive and active engagement in life, self-monitoring and insight, constructive attitudes and approaches and skills and technique acquisition. Inadequate health literacy was independently associated with lower functional well-being and HNC disease-specific HRQL. FoR was also significantly higher among those with inadequate health literacy.

Conclusions: HNC survivors with inadequate health literacy have lower levels of self-management behaviours, lower functional HRQL and increased FoR compared to those with adequate health literacy.

Implications For Cancer Survivors: Clinicians, healthcare providers and those developing interventions should consider how inadequate health literacy among HNC survivors might affect post-treatment outcomes when developing services and providing support for this group.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11764-020-00978-5DOI Listing
January 2021

Kif3a deletion prevents primary cilia assembly on oligodendrocyte progenitor cells, reduces oligodendrogenesis and impairs fine motor function.

Glia 2021 May 24;69(5):1184-1203. Epub 2020 Dec 24.

Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia.

Primary cilia are small microtubule-based organelles capable of transducing signals from growth factor receptors embedded in the cilia membrane. Developmentally, oligodendrocyte progenitor cells (OPCs) express genes associated with primary cilia assembly, disassembly, and signaling, however, the importance of primary cilia for adult myelination has not been explored. We show that OPCs are ciliated in vitro and in vivo, and that they disassemble their primary cilia as they progress through the cell cycle. OPC primary cilia are also disassembled as OPCs differentiate into oligodendrocytes. When kinesin family member 3a (Kif3a), a gene critical for primary cilium assembly, was conditionally deleted from adult OPCs in vivo (Pdgfrα-CreER™:: Kif3a transgenic mice), OPCs failed to assemble primary cilia. Kif3a-deletion was also associated with reduced OPC proliferation and oligodendrogenesis in the corpus callosum and motor cortex and a progressive impairment of fine motor coordination.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/glia.23957DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7986221PMC
May 2021