46 research outputs found

    Safety and Its Ethical Challenges for the Christian Engineer in a Technological Society

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    In every major corporation safety is a high priority and corporate policy statements stress the company’s commitment to keep people and the environment safe. However, safety comes at a cost. Corporations are in business to make profits by providing quality products and services for consumers at affordable prices. Engineers play a critical role in the design, construction, and operation of corporations across the globe and are constantly challenged to find new ways of doing things in order to reduce operating expenses in a competitive global economy. Companies must keep pace with the latest technological innovation or face the prospects of going out of business. Constant economic pressures put engineers in positions to make tough decisions about where to cut costs. When safety is compromised for economic reasons or any other reason, people and the environment are at risk. For the Christian engineer, these ethical decisions may be different and rise to a higher standard than that required by a corporation’s code of ethics[1]. A Christian engineer motivated by faith in God and acting on biblical principles will often reach different conclusions from those operating strictly from a corporate business model based on maximizing profits. Philosophical ethical systems fall short of the Biblical ideal[2]. In facing ethical challenges related to safety, the Christian engineer should propose strategies and standards that follow from the command, “Love your neighbor as yourself.” [1] Martin, M., & Schinzinger, R. (1996). Ethics in Engineering. New York: McGraw-Hill. [2] Holmes, A. F. (2007). Ethics: Approaching Moral Decisions. Downers Grove, IL: InterVarsity Press

    DYNAMIC RELAXATION PROPERTIES OF AROMATIC POLYIMIDES AND POLYMER NANOCOMPOSITES

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    The dynamic relaxation characteristics of Matrimid® (BTDA-DAPI) polyimide and several functionalized aromatic polyimides have been investigated using dynamic mechanical and dielectric methods. The functionalized polyimides were thermally rearranged to generate polybenzoxazole membranes with controlled free volume characteristics. All polyimides have application in membrane separations and exhibit three motional processes with increasing temperature: two sub-glass relaxations (ƴ and β transitions), and the glass-rubber (α) transition. For Matrimid, the low-temperature ƴ transition is purely non-cooperative, while the β sub-glass transition shows a more cooperative character as assessed via the Starkweather method. For the thermally rearranged polyimides, the ƴ transition is a function of the polymer synthesis method, thermal history, and ambient moisture. The β relaxation shows a dual character with increasing thermal rearrangement, the emerging lower-temperature component reflecting motions encompassing a more compact backbone contour. For the glass-rubber (α) transition, dynamic mechanical studies reveal a strong shift in Tα to higher temperatures and a progressive reduction in relaxation intensity with increasing degree of thermal rearrangement. The dynamic relaxation characteristics of poly(ether imide) and poly(methyl methacrylate) nanocomposites were investigated by dynamic mechanical analysis and dielectric spectroscopy. The nanoparticles used were native and surface-modified fumed silicas. The nanocomposites display a dual glass transition behavior encompassing a bulk polymer glass transition, and a second, higher-temperature transition reflecting relaxation of polymer chain segments constrained owing to their proximity to the particle surface. The position and intensity of the higher-temperature transition varies with particle loading and surface chemistry, and reflects the relative populations of segments constrained or immobilized at the particle-polymer interface. Dielectric measurements, which were used to probe the time-temperature response across the local sub-glass relaxations, indicate no variation in relaxation characteristics with particle loading. Nanocomposite studies were also conducted on rubbery poly(ethylene oxide) networks crosslinked in the presence of MgO or SiO2 nanoparticles. The inclusion of nanoparticles led to a systematic increase in rubbery modulus and a modest positive offset in the measured glass transition temperature (Tα) for both systems. The sizeable increases in gas transport with particle loading reported for certain other rubbery nanocomposite systems were not realized in these crosslinked networks

    Effect of Environmental Conditioning on the Properties of Thermosetting and Thermoplastic-Matrix Composite Materials by Resin Infusion for Marine Applications (PREPRINT)

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    Glass-fibre reinforced polymer (GFRP) laminates were manufactured using Vacuum assisted Resin Transfer Moulding (VaRTM) with a range of thermosetting resins and a novel infusible thermoplastic resin as part of a comprehensive down-selection to identify suitable commercially available resin systems for the manufacture of marine vessels greater than 50 m in length. The effect of immersion in deionised water and in an organic liquid (diesel) on the interlaminar shear strength (ILSS) and glass transition temperature (Tg) was determined. The thermoplastic had the highest Tg of all materials tested and comparable ILSS properties to the epoxy. Immersion in water, however, caused larger reductions in ILSS properties of the thermoplastic compared to the other systems. SEM showed a transition from matrix-dominated failure in the dry condition to failure at the fibre-matrix interface in the wet and organic-wet specimens. The overall performance of the infusible thermoplastic is good when compared to well-established marine resin systems; however, the environmental performance could be improved if the thermoplastic resin is used in conjunction with a fibre sizing that is tailored for use with acrylic-based resin systems

    Supporting patients to prepare for total knee replacement: evidence-, theory- and person-based development of a ‘Virtual Knee School’ digital intervention

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    Introduction Digital delivery of pre-operative total knee replacement (TKR) education and prehabilitation could improve patient outcomes pre- and post-operatively. Rigorously developing digital interventions is vital to help ensure they achieve their intended outcomes whilst mitigating their potential drawbacks. Objective To develop a pre-operative TKR education and prehabilitation digital intervention, the ‘Virtual Knee School’ (VKS). Methods The VKS was developed using an evidence-, theory- and person-based approach. This involved a mixed methods design with four phases. The first three focused on planning the VKS. The final phase involved creating a VKS prototype and iteratively refining it through concurrent think-aloud interviews with nine patients who were awaiting/had undergone TKR. Meta-inferences were generated by integrating findings from all the phases. Results Most participants found the VKS prototype acceptable overall and considered it a valuable resource. Conversely, a minority of participants felt the prototype’s digital format or content did not meet their individual needs. Participants’ feedback was used to refine the prototype’s information architecture, design, and content. Two meta-inferences were generated and recommend: 1.Comprehensive pre-operative TKR education and prehabilitation support should be rapidly accessible in digital and non-digital formats. 2.Pre-operative TKR digital interventions should employ computer- and self-tailoring to account for patients’ individual needs and preferences. Conclusions Integrating evidence, theory, and stakeholders’ perspectives enabled the development of a promising VKS digital intervention for patients awaiting TKR. The findings suggest future research evaluating the VKS is warranted and provide recommendations for optimising pre-operative TKR care. Patient or Public contribution Patient and Public Involvement (PPI) was central throughout the project. For example, PPI representatives contributed to the project planning, were valued members of the Project Advisory Group, had key roles in developing the VKS prototype, and helped disseminate the project findings

    Content and delivery of pre-operative interventions for patients undergoing total knee replacement: A rapid review

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    Background: Total knee replacement (TKR) is a common operation typically performed for end-stage knee osteoarthritis. Patients awaiting TKR often have poor health-related quality of life. Approximately 20% of patients experience persistent pain post-TKR. Pre-operative TKR interventions could improve pre- and post-operative outcomes, but future research is required to inform their design. This review aimed to identify and synthesize recent literature on the content and delivery of pre-operative TKR interventions to help guide future research and clinical practice. Methods: This rapid review included randomized trials of pre-operative TKR interventions (‘outcomes studies’) and primary studies exploring patients’ and/or health professionals’ views of pre-operative TKR interventions (‘views studies’). Medline, Embase, PsycINFO, CINAHL and the Cochrane Central Register of Controlled Trials were searched for English language studies published between January 2009 and December 2020. Eligible studies’ reference lists were screened. Studies were appraised using the Mixed Methods Appraisal Tool. The findings were narratively synthesized using a convergent segregated approach. Results: From 3263 records identified, 52 studies were included (29 outcomes studies, 21 views studies, two outcomes/views studies). The studies’ methodological quality varied but was generally highest in qualitative studies. The outcomes studies investigated education (n=5), exercise (n=20), psychological (n=2), lifestyle (n=1) and/or other interventions (n=5). The views studies addressed education (n=20), exercise (n=3), psychological (n=1), lifestyle (n=4) and/or other interventions (n=1). Only three outcomes studies (two randomized controlled trials (RCTs) and a pilot study) compared the effectiveness of intervention components/delivery approaches. The two RCTs’ results suggest that pre-operative TKR exercise interventions are equally effective regardless of whether they include strength or strength plus balance training and whether they are hospital- or home-based. Personal tailoring and using more than one delivery format were associated with improved outcomes and/or perceived as beneficial for multiple intervention types. Conclusions: Definitive evidence on the optimal design of pre-operative TKR interventions is lacking. Personal tailoring and employing multiple delivery formats appear to be valuable design elements. Preliminary evidence suggests that including balance training and hospital versus home delivery may not be critical design elements for pre-operative TKR exercise interventions

    Arg interacts with cortactin to promote adhesion-dependent cell edge protrusion

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    The molecular mechanisms by which the Abelson (Abl) or Abl-related gene (Arg) kinases interface with the actin polymerization machinery to promote cell edge protrusions during cell–matrix adhesion are unclear. In this study, we show that interactions between Arg and the Arp2/3 complex regulator cortactin are essential to mediate actin-based cell edge protrusion during fibroblast adhesion to fibronectin. Arg-deficient and cortactin knockdown fibroblasts exhibit similar defects in adhesion-dependent cell edge protrusion, which can be restored via reexpression of Arg and cortactin. Arg interacts with cortactin via both binding and catalytic events. The cortactin Src homology (SH) 3 domain binds to a Pro-rich motif in the Arg C terminus. Arg mediates adhesion-dependent phosphorylation of cortactin, creating an additional binding site for the Arg SH2 domain. Mutation of residues that mediate Arg–cortactin interactions abrogate the abilities of both proteins to support protrusions, and the Nck adapter, which binds phosphocortactin, is also required. These results demonstrate that interactions between Arg, cortactin, and Nck1 are critical to promote adhesion-dependent cell edge protrusions

    The James Webb Space Telescope Mission

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    Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4m4m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5m6.5m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

    Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial

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    Background: Many patients with COVID-19 have been treated with plasma containing anti-SARS-CoV-2 antibodies. We aimed to evaluate the safety and efficacy of convalescent plasma therapy in patients admitted to hospital with COVID-19. Methods: This randomised, controlled, open-label, platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]) is assessing several possible treatments in patients hospitalised with COVID-19 in the UK. The trial is underway at 177 NHS hospitals from across the UK. Eligible and consenting patients were randomly assigned (1:1) to receive either usual care alone (usual care group) or usual care plus high-titre convalescent plasma (convalescent plasma group). The primary outcome was 28-day mortality, analysed on an intention-to-treat basis. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936. Findings: Between May 28, 2020, and Jan 15, 2021, 11558 (71%) of 16287 patients enrolled in RECOVERY were eligible to receive convalescent plasma and were assigned to either the convalescent plasma group or the usual care group. There was no significant difference in 28-day mortality between the two groups: 1399 (24%) of 5795 patients in the convalescent plasma group and 1408 (24%) of 5763 patients in the usual care group died within 28 days (rate ratio 1·00, 95% CI 0·93–1·07; p=0·95). The 28-day mortality rate ratio was similar in all prespecified subgroups of patients, including in those patients without detectable SARS-CoV-2 antibodies at randomisation. Allocation to convalescent plasma had no significant effect on the proportion of patients discharged from hospital within 28 days (3832 [66%] patients in the convalescent plasma group vs 3822 [66%] patients in the usual care group; rate ratio 0·99, 95% CI 0·94–1·03; p=0·57). Among those not on invasive mechanical ventilation at randomisation, there was no significant difference in the proportion of patients meeting the composite endpoint of progression to invasive mechanical ventilation or death (1568 [29%] of 5493 patients in the convalescent plasma group vs 1568 [29%] of 5448 patients in the usual care group; rate ratio 0·99, 95% CI 0·93–1·05; p=0·79). Interpretation: In patients hospitalised with COVID-19, high-titre convalescent plasma did not improve survival or other prespecified clinical outcomes. Funding: UK Research and Innovation (Medical Research Council) and National Institute of Health Research
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