Now showing items 1-20 of 7475

    • Regional Exploration and Characterisation of CO 2 Storage Prospects in the Utsira-Skade Aquifer, North Viking Graben, North Sea

      Lloyd, C.; email: christopher.lloyd-2@manchester.ac.uk; Huuse, M.; Barrett, B. J.; Newton, A. M. W. (Frontiers Media S.A., 2021-10-04)
      Subsurface CO2 storage is considered a key element of reducing anthropogenic emissions in virtually all scenarios compatible with limiting global warming to 1.5°C. The Utsira-Skade Aquifer (Utsira, Eir and Skade Formations), northern North Sea, has been identified as a suitable reservoir. Although the overall storage capacity of the full aquifer has been estimated based on regional data, it is lacking an integrated assessment of containment and internal heterogeneity, to identify optimal areas for injection and for calculation of site-specific storage capacities. A high-resolution, broadband 3D seismic reflection dataset, full waveform inverted velocity data and 102 exploration wells are utilised to provide a catalogue of CO2 storage prospects in the northern Utsira-Skade Aquifer. This is achieved through: 1) definition of the aquifer’s spatial limits; 2) calculation of porosity distribution; 3) assessment of the extent, geomorphology, thickness variability, and containment confidence (CC) of mudstones; and 4) mapping of closures through fill-to-spill simulations. CO2 storage capacity was calculated for the prospects using two approaches; using the full reservoir thickness (FRT) beneath the closures and using only the thickness from the closure top to the spill point (TSP), i.e., within structural traps. Porosity ranges from 29 to 39% across the aquifer and is higher in the Utsira and Eir Fms. relative to the underlying Skade Fm. The mudstone separating the Skade and Eir/Utsira Fm. has a thickness > 50 m, and is a potential barrier for CO2. Other intra-aquifer mudstones were mainly interpreted to act as baffles to flow. Structural traps at the top Utsira and Skade Fms. yield fifteen prospects, with criteria of > 700 m depth and FRT storage capacity of > 5 Mt CO2. They have a combined storage capacity of 330 Mt CO2 (FRT) or 196 Mt CO2 (TSP). Five prospects have a positive CC score (total capacity: 54 Mt CO2 FRT or 39 Mt CO2 TSP). Additional storage capacity could be achieved through more detailed analysis of the seal to upgrade the CC scores, or through use of a network of the mapped closures with a fill-to-spill approach, utilising more of the aquifer.
    • Visual impairment and medication safety: a protocol for a scoping review.

      Giles, Sally J; orcid: 0000-0003-1623-6029; email: sally.giles@manchester.ac.uk; Panagioti, Maria; Riste, Lisa; Cheraghi-Sohi, Sudeh; Lewis, Penny; Adeyemi, Isabel; Davies, Karen; Morris, Rebecca; Phipps, Denham; Dickenson, Christine; et al. (2021-09-15)
      <h4>Background</h4>The number of individuals with a visual impairment in the UK was estimated a few years ago to be around 1.8 million. People can be visually impaired from birth, childhood, early adulthood or later in life. Those with visual impairment are subject to health inequities and increased risk for patient safety incidents in comparison to the general population. They are also known to be at an increased risk of experiencing medication errors compared to those without visual impairment. In view of this, this review aims to understand the issues of medication safety for VI people.<h4>Methods/design</h4>Four electronic bibliographic databases will be searched: MEDLINE, Embase, PsycInfo and CINAHL. Our search strategy will include search combinations of two key blocks of terms. Studies will not be excluded based on design. Included studies will be empirical studies. They will include studies that relate to both medication safety and visual impairment. Two reviewers (SG and LR) will screen all the titles and abstracts. SG, LR, RM, SCS and PL will perform study selection and data extraction using standard forms. Disagreements will be resolved through discussion or third party adjudication. Data to be collected will include study characteristics (year, objective, research method, setting, country), participant characteristics (number, age, gender, diagnoses), medication safety incident type and characteristics.<h4>Discussion</h4>The review will summarise the literature relating to medication safety and visual impairment.
    • Parental Licensing as Harm Reduction

      Shields, Liam; orcid: 0000-0001-9272-1937; email: liam.shields@manchester.ac.uk (Springer US, 2020-10-17)
      Abstract: In this paper, I will argue that some prominent objections to parental licensing rely on dubious claims about the existence of a very stringent, if not indefeasible, right to parent, which would be violated by licensing. I claim that attaching such stringency to the right only makes sense if we make a number of idealising assumptions. Otherwise, it is deeply implausible. Instead, I argue that we should evaluate parental licensing policies in much the same way we would harm reduction policies. By adopting this critical perspective, we can see that there are powerful, but quite different, reasons to be cautious about parental licensing relating to our ability to minimize the harmful effects of mass-parenting in a world of minimal surveillance and intervention.
    • Stress Corrosion Cracking of Additively Manufactured Alloy 625

      Cabrini, Marina; orcid: 0000-0003-3901-8657; email: marina.cabrini@unibg.it; Lorenzi, Sergio; orcid: 0000-0002-1337-7590; email: sergio.lorenzi@unibg.it; Testa, Cristian; orcid: 0000-0002-6064-9851; email: cristian.testa@guest.unibg.it; Carugo, Francesco; email: francesco.carugo@unibg.it; Pastore, Tommaso; orcid: 0000-0002-1443-7786; email: tommaso.pastore@unibg.it; Manfredi, Diego; orcid: 0000-0002-2876-143X; email: diego.manfredi@polito.it; Biamino, Sara; orcid: 0000-0003-1840-7717; email: sara.biamino@polito.it; Marchese, Giulio; orcid: 0000-0002-4637-5532; email: giulio.marchese@polito.it; Parizia, Simone; orcid: 0000-0002-1616-2800; email: simone.parizia@polito.it; Scenini, Fabio; orcid: 0000-0002-8974-4860; email: fabio.scenini@manchester.ac.uk (MDPI, 2021-10-15)
      Laser bed powder fusion (LPBF) is an additive manufacturing technology for the fabrication of semi-finished components directly from computer-aided design modelling, through melting and consolidation, layer upon layer, of a metallic powder, with a laser source. This manufacturing technique is particularly indicated for poor machinable alloys, such as Alloy 625. However, the unique microstructure generated could modify the resistance of the alloy to environment assisted cracking. The aim of this work was to analyze the stress corrosion cracking (SCC) and hydrogen embrittlement resistance behavior of Alloy 625 obtained by LPBF, both in as-built condition and after a standard heat treatment (grade 1). U-bend testing performed in boiling magnesium chloride at 155 and 170 °C confirmed the immunity of the alloy to SCC. However, slow strain rate tests in simulated ocean water on cathodically polarized specimens highlighted the possibility of the occurrence of hydrogen embrittlement in a specific range of strain rate and cathodic polarization. The very fine grain size and dislocation density of the thermally untreated specimens appeared to increase the hydrogen diffusion and embrittlement effect on pre-charged specimens that were deformed at the high strain rate. Conversely, heat treatment appeared to mitigate hydrogen embrittlement at high strain rates, however at the slow strain rate all the specimens showed a similar behavior.
    • Replication catastrophe is responsible for intrinsic PAR glycohydrolase inhibitor-sensitivity in patient-derived ovarian cancer models

      Coulson-Gilmer, Camilla; Morgan, Robert D.; Nelson, Louisa; Barnes, Bethany M.; Tighe, Anthony; Wardenaar, René; Spierings, Diana C. J.; Schlecht, Helene; Burghel, George J.; Foijer, Floris; et al. (BioMed Central, 2021-10-16)
      Abstract: Background: Patients with ovarian cancer often present at advanced stage and, following initial treatment success, develop recurrent drug-resistant disease. PARP inhibitors (PARPi) are yielding unprecedented survival benefits for women with BRCA-deficient disease. However, options remain limited for disease that is platinum-resistant and/or has inherent or acquired PARPi-resistance. PARG, the PAR glycohydrolase that counterbalances PARP activity, is an emerging target with potential to selectively kill tumour cells harbouring oncogene-induced DNA replication and metabolic vulnerabilities. Clinical development of PARG inhibitors (PARGi) will however require predictive biomarkers, in turn requiring an understanding of their mode of action. Furthermore, differential sensitivity to PARPi is key for expanding treatment options available for patients. Methods: A panel of 10 ovarian cancer cell lines and a living biobank of patient-derived ovarian cancer models (OCMs) were screened for PARGi-sensitivity using short- and long-term growth assays. PARGi-sensitivity was characterized using established markers for DNA replication stress, namely replication fibre asymmetry, RPA foci, KAP1 and Chk1 phosphorylation, and pan-nuclear γH2AX, indicating DNA replication catastrophe. Finally, gene expression in sensitive and resistant cells was also examined using NanoString or RNAseq. Results: PARGi sensitivity was identified in both ovarian cancer cell lines and patient-derived OCMs, with sensitivity accompanied by markers of persistent replication stress, and a pre-mitotic cell cycle block. Moreover, DNA replication genes are down-regulated in PARGi-sensitive cell lines consistent with an inherent DNA replication vulnerability. However, DNA replication gene expression did not predict PARGi-sensitivity in OCMs. The subset of patient-derived OCMs that are sensitive to single-agent PARG inhibition, includes models that are PARPi- and/or platinum-resistant, indicating that PARG inhibitors may represent an alternative treatment strategy for women with otherwise limited therapeutic options. Conclusions: We discover that a subset of ovarian cancers are intrinsically sensitive to pharmacological PARG blockade, including drug-resistant disease, underpinned by a common mechanism of replication catastrophe. We explore the use of a transcript-based biomarker, and provide insight into the design of future clinical trials of PARGi in patients with ovarian cancer. However, our results highlight the complexity of developing a predictive biomarker for PARGi sensitivity.
    • A Lucas–Lehmer approach to generalised Lebesgue–Ramanujan–Nagell equations

      Patel, Vandita; orcid: 0000-0003-0252-963X; email: vandita.patel@manchester.ac.uk (Springer US, 2021-06-10)
      Abstract: We describe a computationally efficient approach to resolving equations of the form C1x2+C2=yn in coprime integers, for fixed values of C1, C2 subject to further conditions. We make use of a factorisation argument and the Primitive Divisor Theorem due to Bilu, Hanrot and Voutier.
    • BioID-based proteomic analysis of the Bid interactome identifies novel proteins involved in cell-cycle-dependent apoptotic priming

      Pedley, Robert; orcid: 0000-0002-0801-7240; King, Louise E.; Mallikarjun, Venkatesh; Wang, Pengbo; Swift, Joe; Brennan, Keith; Gilmore, Andrew P.; orcid: 0000-0002-9988-0436; email: agilmore@manchester.ac.uk (Nature Publishing Group UK, 2020-10-16)
      Abstract: Apoptotic priming controls the commitment of cells to apoptosis by determining how close they lie to mitochondrial permeabilisation. Variations in priming are important for how both healthy and cancer cells respond to chemotherapeutic agents, but how it is dynamically coordinated by Bcl-2 proteins remains unclear. The Bcl-2 family protein Bid is phosphorylated when cells enter mitosis, increasing apoptotic priming and sensitivity to antimitotic drugs. Here, we report an unbiased proximity biotinylation (BioID) screen to identify regulators of apoptotic priming in mitosis, using Bid as bait. The screen primarily identified proteins outside of the canonical Bid interactome. Specifically, we found that voltage-dependent anion-selective channel protein 2 (VDAC2) was required for Bid phosphorylation-dependent changes in apoptotic priming during mitosis. These results highlight the importance of the wider Bcl-2 family interactome in regulating the temporal control of apoptotic priming.
    • Process-Dependent Solute Transport in Porous Media

      Erfani, Hamidreza; orcid: 0000-0002-9472-555X; Karadimitriou, Nikolaos; Nissan, Alon; Walczak, Monika S.; An, Senyou; Berkowitz, Brian; Niasar, Vahid; email: vahid.niasar@manchester.ac.uk (Springer Netherlands, 2021-10-01)
      Abstract: Solute transport under single-phase flow conditions in porous micromodels was studied using high-resolution optical imaging. Experiments examined loading (injection of ink-water solution into a clear water-filled micromodel) and unloading (injection of clear water into an ink-water filled micromodel). Statistically homogeneous and fine-coarse porous micromodels patterns were used. It is shown that the transport time scale during unloading is larger than that under loading, even in a micromodel with a homogeneous structure, so that larger values of the dispersion coefficient were obtained for transport during unloading. The difference between the dispersion values for unloading and loading cases decreased with an increase in the flow rate. This implies that diffusion is the key factor controlling the degree of difference between loading and unloading transport time scales, in the cases considered here. Moreover, the patterned heterogeneity micromodel, containing distinct sections of fine and coarse porous media, increased the difference between the transport time scales during loading and unloading processes. These results raise the question of whether this discrepancy in transport time scales for the same hydrodynamic conditions is observable at larger length and time scales.
    • Knowledge and the Fall in American Neo-Calvinism: Toward a Van Til–Plantinga Synthesis

      Békefi, Bálint; email: balint.bekefi@gmail.com (Brill, 2021-09-17)
      Abstract Cornelius Van Til and Alvin Plantinga represent two strands of American Protestant philosophical thought influenced by Dutch neo-Calvinism. This paper compares and synthetizes their models of knowledge in non-Christians given the noetic effects of sin and non-Christian worldview commitments. The paper argues that Van Til’s distinction between the partial realization of the antithesis in practice and its absolute nature in principle correlates with Plantinga’s insistence on prima facie–warranted common-sense beliefs and their ultimate defeasibility given certain metaphysical commitments. Van Til endorsed more radical claims than Plantinga on epistemic defeat in non-Christian worldviews, the status of the sensus divinitatis, and conceptual accuracy in knowledge of the world. Finally, an approach to the use of evidence in apologetics is developed based on the proposed synthesis. This approach seeks to make more room for evidence than is generally recognized in Van Tilianism, while remaining consistent with the founder’s principles.
    • The enduring effect of early life adversities on health trajectories.

      Webb, Roger T; email: roger.webb@manchester.ac.uk; John, Ann; Mytton, Julie (2021-09-29)
    • Distance, Time, Speed & Energy: A socio-political analysis of technologies of longer distance cycling

      Cox, Peter; orcid: 0000-0003-2374-3125 (University of Westminster Press, 2021-10-07)
      The basic laws of motion governing cycling are wellunderstood. Consideration of the variables of energy use in cycle travel areless frequent. The potentials of both aerodynamically efficient cycle designand the augmentation of human power with e-motors dramatically reconfigure whatwe understand as a cycle and as cycling. The prospect of increasing travel distance in regularjourneying, coupled with the logical application of augmentation (aerodynamicand/ or power), suggest a need to re-evaluate some of the ground expectationsapplied in design and planning for cycle travel if the cycles being designedfor do not fit the existing expectations of what a cycle is and how itperforms. Current e-bike performance is limited principally bynormative legislative intervention, not by the intrinsic potential of thetechnologies. Existing decisions as to what an e-bike can (and should) be, areshaped by the performance expectations of late 19th and early 20thcentury bicycle designs. Shaping modal shift for longer trips returns us tothink about the place of cycling travel time as a function of the relationshipbetween distance and speed. Increased speed allows for greater distance withouttime penalty. However, speed is itself governed by available energy, coupledwith the efficiency of use of that energy. Without entirely substituting humanpower, E-motors allow us to augment the human power available in differentways; Changes in cycle design (as us, for example, in velomobiles) allow us toincrease the efficiency of use of available power in overcoming resistance tomovementIdentifying the assemblage of cycle/cyclist as avariable, rather than a determinate object to be accommodated, raises difficultquestions for cycling provision, especially in relation to longer distancetravel.This paper takes an approach rooted in Actor NetworkTheory and developed through social practice analysis to explore theinteractions of people machines and spaces for longer distance travel. It paysparticular attention to the capacities and affordances of each of theseelements, especially in their interaction. Drawing on the capacities of already existingtechnologies of cycling and e-cycling, the paper focuses on the socialimplications of potentially problematic interactions. It argues that newdecisions will need to be made in regard to speed and distance in cycle traveland that the forging of regulations consequent on those fundamentals&amp;nbsp; will substantially shape the potentials andpossibilities of modal shift for longer distance cycle travel. What emerges isa politics of longer distance cycle, not simply a set of technical barriers andproblems.
    • Environmental Assessment of Latent Heat Thermal Energy Storage Technology System with Phase Change Material for Domestic Heating Applications

      Chocontá Bernal, Daniel; email: Daniel.chocontabernal@postgrad.manchester.ac.uk; Muñoz, Edmundo; orcid: 0000-0002-7258-6069; email: edmundo.munoz@unab.cl; Manente, Giovanni; orcid: 0000-0001-7134-8731; email: G.Manente@bham.ac.uk; Sciacovelli, Adriano; orcid: 0000-0001-9684-3122; email: a.sciacovelli@bham.ac.uk; Ameli, Hossein; orcid: 0000-0003-4056-9819; email: h.ameli14@imperial.ac.uk; Gallego-Schmid, Alejandro; email: alejandro.gallegoschmid@manchester.ac.uk (MDPI, 2021-10-13)
      The emissions generated by the space and water heating of UK homes need to be reduced to meet the goal of becoming carbon neutral by 2050. The combination of solar (S) collectors with latent heat thermal energy storage (LHTES) technologies with phase change materials (PCM) can potentially help to achieve this goal. However, there is limited understanding of the environmental sustainability of LHTES technologies from a full life cycle perspective. This study assesses for the first time 18 environmental impacts of a full S-LHTES-PCM system from a cradle to grave perspective and compares the results with the most common sources of heat in UK homes. The results show that the system’s main environmental hotspots are the solar collector, the PCM, the PCM tank, and the heat exchanger. The main cause of most of the impacts is the extensive consumption of electricity and heat during the production of raw materials for these components. The comparison with other sources of household heat (biomass, heat pump, and natural gas) indicates that the S-LHTES-PCM system generates the highest environmental impact in 11 of 18 categories. However, a sensitivity analysis based on the lifetime of the S-LHTES-PCM systems shows that, when the lifetime increases to 40 years, almost all the impacts are significantly reduced. In fact, a 40-year S-LHTES-PCM system has a lower global warming potential than natural gas.
    • Detection of MCM5 as a novel non-invasive aid for the diagnosis of endometrial and ovarian tumours

      Stockley, J.; Akhand, R.; Kennedy, A.; Nyberg, C.; Crosbie, E. J.; Edmondson, R. J.; orcid: 0000-0003-2553-4423; email: richard.edmondson@manchester.ac.uk (BioMed Central, 2020-10-15)
      Abstract: Background: MCM5 is a protein involved in DNA replication, facilitating cell proliferation. In normal epithelium MCM5 expression is restricted to the cells in the basal proliferative compartments, however in the presence of a tumour MCM5 positive cells are present at the surface epithelium and are shed into bodily fluids. The aim of this study was to determine the sensitivity of MCM5 as a biomarker for the detection of endometrial and ovarian cancer. Methods: Patients with known ovarian or endometrial cancers, or known benign gynaecological conditions, were enrolled. Informed consent was obtained prior to the collection of full void urine, and either a vaginal tampon (worn for 6–8 h), or a vaginal swab. Vaginal secretions were extracted from the tampon or swab, centrifuged and lysed. Urine samples were centrifuged and lysed. MCM5 levels were determined by MCM5-ELISA (Arquer Diagnostics Ltd). Results: 125 patients completed the study protocol, 41 patients had endometrial cancer, 26 ovarian cancer, and 58 benign controls. All patients provided a urine sample and either a tampon or vaginal swab sample. Urine MCM5 levels were higher in cancer patients than controls (p < 0.0001), there was no significant difference in levels between tampon samples or vaginal swab samples in cancer patients when compared to controls. Performance of MCM5 to discriminate cancer from benign disease was high with an area under the ROC curve of 0.83 for endometrial cancer and 0.68 for ovarian cancer. Using a cut off of 12 pg/mL, overall sensitivity for endometrial cancer was 87.8, and 61.5% for ovarian cancer with a specificity of 75.9%. Conclusions: MCM5 is a novel sensitive and specific biomarker for the detection of ovarian and endometrial tumours in urine samples, which is likely to have clinical utility as a diagnostic aid.
    • The Challenges of Measuring Informal Care Time: A Review of the Literature

      Urwin, Sean; orcid: 0000-0002-9084-8368; email: sean.urwin@manchester.ac.uk; Lau, Yiu-Shing; Grande, Gunn; Sutton, Matt (Springer International Publishing, 2021-07-29)
      Abstract: Economic evaluations increasingly include the value of informal care, for example, in terms of caregiver health effects or time costs. If an economic evaluation uses caregiving time costs, appropriate measurement of caregiving time is an important first step prior to its valuation. There is no comprehensive overview of the measurement challenges for caregiving time. In this literature review, we searched Medline, Embase, Econlit and Scopus to identify measurement issues and associated studies which reported informal care time that addressed them. The search identified 27 studies that addressed nine measurement issues. There is limited evidence on how to address these issues, although some have received relatively more attention, including incremental time (considered in 16 studies), time measurement method comparisons (six studies) and the inclusion of intangible tasks (four studies). Non-response (considered in only one study) and carer and recipient identification (two studies) were the most wide-reaching measurement concerns, as these determine who is identified as carers. There was no evidence on the consequences of these measurement challenges in terms of impacts on cost-effectiveness ratios and on the total cost of health conditions, which would be a crucial next step. Future research on these issues should consider a range of different settings, as informal care is highly heterogeneous. The measurement of informal care is key for its inclusion in economic evaluations but there is little consensus on how to appropriately measure this type of care.
    • The impact of COVID-19 on digital data practices in museums and art galleries in the UK and the US

      Noehrer, Lukas; orcid: 0000-0002-9167-0397; email: lukas.noehrer@manchester.ac.uk; Gilmore, Abigail; Jay, Caroline; Yehudi, Yo; orcid: 0000-0003-2705-1724 (Palgrave Macmillan UK, 2021-10-15)
      Abstract: The first quarter of 2020 heralded the beginning of an uncertain future for museums and galleries as the COVID-19 pandemic hit and the only means to stay ‘open’ was to turn towards the digital. In this paper, we investigate how the physical closure of museum buildings due to lockdown restrictions caused shockwaves within their digital strategies and changed their data practices potentially for good. We review the impact of COVID-19 on the museum sector, based on literature and desk research, with a focus on the implications for three museums and art galleries in the United Kingdom and the United States, and their mission, objectives, and digital data practices. We then present an analysis of ten qualitative interviews with expert witnesses working in the sector, representing different roles and types of institutions, undertaken between April and October 2020. Our research finds that digital engagement with museum content and practices around data in institutions have changed and that digital methods for organising and accessing collections for both staff and the general public have become more important. We present evidence that strategic preparedness influenced how well institutions were able to transition during closure and that metrics data became pivotal in understanding this novel situation. Increased engagement online changed traditional audience profiles, challenging museums to find ways of accommodating new forms of engagement in order to survive and thrive in the post-pandemic environment.
    • The Effect of Authigenic Clays on Fault Zone Permeability

      Farrell, N. J. C.; orcid: 0000-0002-8491-9094; email: natalie.farrell@manchester.ac.uk; Debenham, N.; Wilson, L.; Wilson, M. J.; Healy, D.; orcid: 0000-0003-2685-1498; King, R. C.; Holford, S. P.; orcid: 0000-0002-4524-8822; Taylor, C. W. (2021-10-15)
      Abstract: Clays are understood to form the majority of fluid‐flow barriers in faulted reservoirs and numerous fault gouge and fault seal studies have quantified the volumes of smeared and abraded clays create fluid‐flow barriers along fault surfaces. However, clay‐related permeability adjacent to the fault surface, including in the fault damage zone, has largely been neglected. Previous studies have shown the morphology and distribution of unfaulted authigenic clays, and not just clay volume, exert a significant control on the magnitude of permeability. However, fault‐related studies have neither characterized deformed authigenic clays nor addressed their influence on fluid‐flow. In this study laboratory permeabilities of faulted, authigenic clay bearing sandstones sampled from the Otway basin (Australia) and the Orcadian basin (UK) present trends which; (a) do not correspond to expected patterns of fluid‐flow in faulted clay‐bearing sandstones and, (b) cannot be explained using published models of permeability related to changing clay volume. Microscopic analysis shows that faulting has disaggregated authigenic clays and, similarly to framework grain deformation, comminuted and sheared clay grains. However, instead of impeding fluid‐flow, analysis of pore networks (using mercury injection porosimetry) showed that faulting of authigenic clays has increased pore connectivity, contributing to increased magnitude of permeability and development of permeability anisotropy. Contrary to published results of faulting and fluid‐flow in impure sandstones, our results show that fault related processes involving the formation of clays in the fault zone can increase permeability and reduce the capillary threshold pressures of fault rocks relative to the unfaulted host rock.
    • To investigate the ambidextrous challenges and tensions of small and medium enterprises in the United Kingdom defence & security sector

      Wall, Tony; Moore, Neil; Lewis, Christopher C. (University of Chester, 2021-05)
      The defence and security industry is an extremely dynamic environment, influenced by policy and world events. Whilst it often needs to respond to rapid change, there is a dichotomy in that capital programs take years to come to fruition. Many small and medium-sized enterprises (SMEs) are involved in both of these short and long-term aspects of acquisition, thus creating strategic challenges. Though there has been much research around ambidexterity and SMEs, there has been very little in the fluid domain of defence and security supply-side SMEs. This study aims to investigate this gap in research. The investigation collected primary qualitative data through the use of semi-structured interviews, with research participants constituting the leadership functions of eighteen businesses that deliver either directly to the defence and security governmental departments, or into the supply chain. Findings indicate that within a shrinking defence sector, successful SMEs are operating in an ambidextrous fashion, often utilising the industrial partners of the industry trade organisations. Also, outside that of grand strategic change, Government policy has a limited impact on the SMEs in this sector. With scarce resources, the leadership of businesses see the competing needs of resource and finances as a major tension point. These two competing needs can be defined as exploration and exploitation respectively, and can be situated within an ambidextrous construct. Critically, successful businesses operate in a ambidextrous zone where there is constant iterative adjustment between both exploration and exploitation. This thesis advances the thought leadership in SME strategy, particularly around the key indigenous industry of defence and security, thereby adjusting the understanding of the definition of ambidexterity. This study contributes to the current literature, through the development of an alternative and responsive conceptual dynamic model of a growing business, theorising that ambidexterity functions change as SMEs grow, are constantly evolving, and are adjusted by both internal and external influences. The study concludes with recommendations for practice.
    • Working with risk within the counselling professions

      Reeves, Andrew; University of Chester (British Association for Counselling and Psychotherapy, 2021-09-20)
      This practitioner factsheet looks at the factors that counsellors and psychotherapists need to keep in mind when working with clients who present at risk. Good practice indicators are outlined, as well as evidence-informed interventions.
    • Post-irradiation surface viscoelastic integrity of photo-polymerized resin-based composites.

      Algamaiah, Hamad; email: dr.algamaiah@gmail.com; Watts, David C; email: david.watts@manchester.ac.uk (2021-09-27)
      A class of ultra-rapid-cure resin-based composites (RBCs) exhibited immediate post-irradiation surface viscoelastic integrity using an indentation-creep/recovery procedure. The aim of this study was to determine whether such behavior is more generally characteristic of a wider range of RBCs. Eight representative RBCs were selected based on different clinical categories: three bulkfills (OBF, Filtek One Bulk Fill; VBF, Venus Bulkfill; EBF, Estelite Bulkfill), three conventional non-flowables (XTE, Filtek Supreme XTE; GSO, GrandioSo; HRZ, Harmonize) and conventional flowables (XTF, Filtek Supreme XTE Flow; GSF, GrandioSo Flow). Stainless steel split molds were used to fabricate cylindrical specimens (4mm (dia)×4mm). These were irradiated (1.2W/cm ) for 20s on the top surface. Post-irradiation specimens (n=3), within their molds, were centrally loaded with a flat-ended 1.5mm diameter indenter under 14MPa stress: either immediately (<2min) or after 24h delayed indentation. Stress was maintained for 2h, then - after removal - recovery measurements continued for a further 2h. Indentation depth (%) versus time was measured continuously to an accuracy of <0.1μm. Data were analyzed by One-way ANOVA and Tukey post-hoc tests (α=0.05). Time-dependent viscoelastic indentation was observed for all RBCs. For immediate indentation, the maximum indentation range was 1.43-4.92%, versus 0.70-2.22% for 24h delayed indentation. Following 2h recovery, the residual indentation range was 0.86-3.58% after immediate indentation, reducing to 0.22-1.27% for delayed indentation. The greatest immediate indentation was shown by VBF followed by XTF and GSF. OBF, HRZ, XTE and GSO had significantly lower indentations (greater hardness). XTE showed a significantly reduced indentation maximum compared to OBF (p<0.05). Indentations delayed until 24h post-irradiation were reduced (p<0.05) for most materials. The indentation-creep methodology effectively characterized resin-based composites within several categories. Viscoelastic properties evaluated by the indentation-creep method confirmed that highly filled RBCs were more resistant to indentation. Indentations were reduced after 24h post-irradiation due to further matrix-network development. [Abstract copyright: Copyright © 2021. Published by Elsevier Inc.]
    • Influence of curing modes on thermal stability, hardness development and network integrity of dual-cure resin cements.

      Aldhafyan, Mohammed; Silikas, Nikolaos; email: nick.silikas@manchester.ac.uk; Watts, David C; email: david.watts@manchester.ac.uk (2021-09-27)
      To explore the effect of different curing modes of conventional and self-adhesive dual-cure resin cements on their rates of thermal decomposition, hardness development and network integrity. Five self-adhesive (PANAVIA SA, RelyX Universal Resin, RelyX Unicem 2, Bifix SE and SpeedCEM Plus) and three conventional (PANAVIA V5, Nexus Third Generation and RelyX Ultimate Universal) dual-cure resin cements were investigated. Thermal decomposition stages, initial onset temperatures, the maximum rate of mass-loss and the filler mass-fraction of each resin cement were analysed by thermogravimetric analysis (TGA). Surface hardness was measured at 1h post-cure and after 24h of dry storage at 37°C. The relative network integrities were estimated from reductions in hardness after 168h of water storage. Data were analysed via one-way ANOVA, Tukey post-hoc tests and paired/independent sample t-tests (a=0.05). No difference was apparent between TGA data for self-cured and light-cured specimens. Numerical differentiation of mass-loss versus temperature showed either single or multiple peaks. For the set of 8 cements, the maximum rate of mass-loss (%/°C) correlated negatively with residual mass at 600°C. All dry-stored cements increased in hardness from 1 to 24h, ranging from 20.4% to 52.6% for light-cure mode and from 41.3% to 112.6% for self-cure. After 168h water storage, the hardness of cements decreased: by 18.5%-36.2% for light-cured and by 9.8%-17.9% for self-cured. Overall, surface hardness was greater for light-cured cements. The initial onset temperature (IOT) of thermal decomposition correlated negatively with the hardness decrease produced by water-storage: r =0.77 for light-cure and r =0.88 for self-cure. This provided the basis for a relative scale of composite network integrity, probably reflecting differences in cross-link density. Light-curing, where possible, remains beneficial to the hardness and related properties of dual-cure resin cements. Combination of TG analysis and solvent softening experiments give an indication of relative network integrity - between materials - and their relative cross-link densities. [Abstract copyright: Copyright © 2021. Published by Elsevier Inc.]