71 results on '"Byrne PA"'
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2. Comparison of Phase Change Materials of Modified Soy Wax using Graphene and MAXene for Thermal Energy Storage Materials in Buildings
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Titin Trisnadewi, Eny Kusrini, Dwi Marta Nurjaya, Byrne Paul, Maré Thierry, and Nandy Putra
- Subjects
graphene ,maxene ,phase change material ,soy wax ,thermal energy storage ,Technology ,Technology (General) ,T1-995 - Abstract
This study aimed to characterize Phase Change Materials (PCM) by improving their properties using shape stabilization; this was achieved by adding nanoparticles as a support material. PCM soy wax was modified using two nanoparticles, graphene, and MAXene Ti3AlC2. The synthesis process comprised stirring using a magnetic stirrer and ultrasonication using an ultrasonic processor with various percentages of 0.1, 0.5, and 1 wt.% of soy wax with nanoparticles. Based on the results, the morphologies of graphene and MAXene Ti3AlC2 were found to be in the form of sheets. These sheets had a large surface area, so soy wax could adsorb more nanoparticles to increase the stability of the material. The thermal conductivity increased with increasing percentage addition of nanoparticles. The highest values from the synthesis with graphene and MAXene Ti3AlC2 were 0.89 W/mK and 0.85 W/mK, respectively. The thermal conductivity of soy wax increased with the ratio of pure soy wax and nano-soy wax; the thermal conductivity was 6.01 for soy wax+graphene and 5.71 for soy wax+Ti3AlC2. Differential scanning calorimetry (DSC) results showed an increase in the melting and solidifying points of pure soy wax. The modified soy wax with 0.1 wt.% graphenes experienced a reduction in the melting and solidification points up to 15% and 14%, respectively. Similar results were obtained for 0.1 wt.% MAXene Ti3AlC2. In this case, there was a reduction in the melting and solidifying points by 16% and 13%, respectively. Finally, the addition of MAXene improved the material stability and thermal conductivity of soy wax and has the potential to be used as a thermal energy storage material for building applications.
- Published
- 2023
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3. Transfer of sediments and contaminants in catchments and rivers
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Lopez-Tarazon, JA, Byrne, PA, and van der Perk, M
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GB ,GE
4. New Sensing System Based on Electromagnetic Waves and Functionalised EM Sensors for Continuous Monitoring of Zn in Freshwater
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Frau, I, Wylie, S, Byrne, PA, Cullen, J, Korostynska, O, and Mason, A
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TD - Abstract
Toxic metals are a signi cant cause for concern, considering freshwater the major route of their transport even far from point and di use sources. ¬ is paper presents a novel combined method using electrical measurements and microwave spectroscopy based on functionalised electromagnetic (f-EM) sensors. ¬ ick lms based on -Bi2O3 were screen-printed on planar sensors for monitoring continuously Zn concentrations in water. Results demonstrate the capability of this novel sensing system to measure in real-time Zn concentrations, especially in the range 0-1 mg/L and consequently the possibility to detect an unexpected pollution event, which can generate an increase of Zn in water.
5. Short-term fluctuations in heavy metal concentrations during flood events through abandoned metal mines, with implications for aquatic ecology and mine water treatment
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Byrne, PA, Reid, I, and Wood, PJ
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GE ,fungi ,parasitic diseases ,food and beverages ,humanities - Abstract
The variability in heavy metal concentrations and physico-chemical parameters during rain-fed river floods that pass\ud through abandoned metal mines is poorly understood due to the difficulties of sampling these events. Such information\ud is essential for the characterisation of contaminant dynamics and for investigations of contaminant/ecosystem relations and the effectiveness of remediation. This study investigates the role of flood flows in contaminant mobilisation and temporary increases in toxicity at an abandoned metal mine in central Wales, UK. Flood events substantially increase the potential toxicity of river water. The principal contaminants are dissolved Pb, mobilized by increased acidity resulting from the dissolution and flushing of efflourescent salts accumulated on the surface of mine spoil. The implications of flood runoff and contaminant mobilisation for aquatic ecology and mine water treatment are discussed.
6. Environmental risk of severely Pb-contaminated riverbank sediment as a consequence of hydrometeorological perturbation
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Lynch, SFL, Batty, LC, and Byrne, PA
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GE - Abstract
Metal mining activities have resulted in the widespread metal pollution of soils and sediments and are a worldwide health concern. Pb is often prolific in metal-mining impacted systems and has acute and chronic toxic effects. Environmental factors controlling diffuse pollution from contaminated riverbank sediment are currently seen as a “black box” from a process perspective. This limits our ability to accurately predict and model releases of dissolved Pb. Previous work by the authors uncovered key mechanisms responsible for the mobilisation of dissolved Zn. The current study identifies key mechanisms controlling the mobilisation of dissolved Pb, and the environmental risk these releases pose, in response to various sequences of “riverbank” inundation/drainage. Mesocosm experiments designed to mimic the riverbank environment were run using sediment severely contaminated with Pb, from a mining-impacted site. Results indicated that, although Pb is generally reported as less mobile than Zn, high concentrations of dissolved Pb are released in response to longer or more frequent flood events. Furthermore, the geochemical mechanisms of release for Zn and Pb were different. For Zn, mechanisms were related to reductive dissolution of Mn (hydr)oxides with higher concentrations released, at depth, over prolonged flood periods. For Pb, key mechanisms of release were related to the solubility of anglesite and the oxidation of primary mineral galena, where periodic drainage events serve to keep sediments oxic, particularly at the surface. The results are concerning because climate projections for the UK indicate a rise in the occurrence of localized heavy rainfall events that could increase flood frequency and/or duration. This study is unique in that it is the first to uncover key mechanisms responsible for dissolved Pb mobilisation from riverbank sediments. The mineralogy at the mining-impacted site is common to many sites worldwide and it is likely the mechanisms identified in this study are widespread.
7. Revealing the spatial variability of water fluxes at the groundwater-surface water interface
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Binley, A, Ullah, S, Heathwaite, AL, Heppell, CM, Byrne, PA, Lansdown, K, Trimmer, M, and Zhang, H
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GB - Abstract
There is widespread recognition that the groundwater-surface water interface can have significant influence on the pattern and form of the transfer of nutrient-rich groundwater to rivers. Characterizing and quantifying this influence is critical for successful management of water resources in many catchments, particularly those threatened by rising nitrate levels in groundwater. Building on previous experimental investigations in one such catchment: the River Leith, UK, we report on a multimeasurement, multiscale program aimed at developing a conceptualization of groundwater-surface water flow pathways along a 200 m reach. Key to this conceptualization is the quantification of vertical and horizontal water fluxes, which is achieved through a series of Darcian flow estimates coupled with in-stream piezometer tracer dilution tests. These data, enhanced by multilevel measurements of chloride concentration in riverbed pore water and water-borne geophysical surveying, reveal a contrast in the contribution of flow components along the reach. In the upper section of the reach, a localized connectivity to regional groundwater, that appears to suppress the hyporheic zone, is identified. Further downstream, horizontal (lateral and longitudinal) flows appear to contribute more to the total subsurface flow at the groundwater-surface water interface. Although variation in hydraulic conductivity of the riverbed is observed, localized variation that can account for the spatial variability in flow pathways is not evident. The study provides a hydrological conceptualization for the site, which is essential for future studies which address biogeochemical processes, in relation to nitrogen retention/release. Such a conceptualization would not have been possible without a multiexperimental program.
8. Control of river stage on the reactive chemistry of the hyporheic zone
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Byrne, PA, Binley, A, Heathwaite, AL, Ullah, S, Heppell, CM, Lansdown, K, Zhang, H, Trimmer, M, and Keenan, P
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GE - Abstract
We examined the influence of river stage on subsurface hydrology and pore water chemistry within the hyporheic zone of a groundwater-fed river during the summer baseflow period of 2011. We found river stage and geomorphologic environment to control chemical patterns in the hyporheic zone. At high river stage, the flux of upwelling water in the shallow sediments (> 20 cm) decreased at samples sites in the upper section of our study reach and increased substantially at sites in the lower section. This differential response is attributed to the contrasting geomorphology of these sub-reaches which affects the rate of the rise and fall of river stage relative to subsurface head. At sites where streamward vertical flux decreased, concentration profiles of a conservative environmental tracer suggest surface water infiltration into the riverbed below depths recorded at low river stage. An increase in vertical flux at sites in the lower sub-reach is attributed to the movement of lateral subsurface waters originating from the adjacent floodplain. This lateral-moving water preserved or decreased the vertical extent of the hyporheic mixing zone observed at low river stage. Down welling surface water appeared to be responsible for elevated dissolved organic carbon (DOC) and Mn concentrations in shallow sediments (0 – 20 cm); however, lateral subsurface flows were probably important for elevated concentrations of these solutes at deeper levels. Results suggest that DOC delivered to hyporheic sediments during high river stage from surface water and lateral subsurface sources could enhance heterotrophic microbial activities. This article is protected by copyright. All rights reserved.
9. Source apportionment of metal mine pollution in Wanlock Water using tracer injection and synoptic sampling
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Byrne, PA and Yendell, A
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GE - Abstract
Scottish Environment Protection Agency Repor
10. Training medical students on rare disorders
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Byrne Paula C
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Medicine - Published
- 2012
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11. Anencephaly--organ transplantation?
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Byrne PA and Evers JC
- Published
- 1993
12. Regioselective Partial Hydrogenation and Deuteration of Tetracyclic (Hetero)aromatic Systems Using a Simple Heterogeneous Catalyst.
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Kehoe RA, Lowry A, Light ME, Jones DJ, Byrne PA, and McGlacken GP
- Abstract
The introduction of added '3-dimensionality' through late-stage functionalisation of extended (hetero)aromatic systems is a powerful synthetic approach. The abundance of starting materials and cross-coupling methodologies to access the precursors allows for highly diverse products. Subsequent selective partial reduction can alter the core structure in a manner of interest to medicinal chemists. Herein, we describe the precise, partial reduction of multicyclic heteroaromatic systems using a simple heterogeneous catalyst. The approach can be extended to introduce deuterium (again at late-stage). Excellent yields can be obtained using simple reaction conditions., (© 2024 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)
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- 2024
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13. Addressing nutrient shortfalls in 1- to 5-year-old Irish children using diet modeling: development of a protocol for use in country-specific population health.
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Lyons OC, Kerr MA, McNulty H, Ward F, Walton J, Livingstone MBE, McNulty BA, Kehoe L, Byrne PA, Saul I, and Flynn MAT
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- Animals, Child, Preschool, Eating, Feeding Behavior, Female, Humans, Infant, Ireland, Male, Milk, Nutrition Surveys, Population Health, Reference Values, Child Nutrition Disorders prevention & control, Diet, Healthy standards, Nutrition Policy
- Abstract
Background: Dietary habits formed in early childhood can track into later life with important impacts on health. Food-based dietary guidelines (FBDGs) may have a role in improving population health but are lacking for young children., Objectives: We aimed to establish a protocol for addressing nutrient shortfalls in 1- to 5-y-old children (12-60 mo) using diet modeling in a population-based sample., Methods: Secondary analysis of 2010-2011 Irish National Pre-School Nutrition Survey data (n = 500) was conducted to identify typical food consumption patterns in 1- to 5-y-olds. Nutrient intakes were assessed against dietary reference values [European Food Safety Authority (EFSA) and Institute of Medicine (IOM)]. To address nutrient shortfalls using diet modeling, 4-d food patterns were developed to assess different milk-feeding scenarios (human milk, whole or low-fat cow milk, and fortified milks) within energy requirement ranges aligned with the WHO growth standards. FBDGs to address nutrient shortfalls were established based on 120 food patterns., Results: Current mean dietary intakes for the majority of 1- to 5-y-olds failed to meet reference values (EFSA) for vitamin D (≤100%), vitamin E (≤88%), DHA (22:6n-3) + EPA (20:5n-3) (IOM; ≤82%), and fiber (≤63%), whereas free sugars intakes exceeded recommendations of <10% energy (E) for 48% of 1- to 3-y-olds and 75% of 4- to 5-y-olds. "Human milk + Cow milk" was the only milk-feeding scenario modeled that predicted sufficient DHA + EPA among 1- to 3-y-olds. Vitamin D shortfalls were not correctable in any milk-feeding scenario, even with supplementation (5 µg/d), apart from the "Follow-up Formula + Fortified drink" scenario in 1- to 3-y-olds (albeit free sugars intakes were estimated at 12%E compared with ≤5%E as provided by other scenarios). Iron and vitamin E shortfalls were most prevalent in scenarios for 1- to 3-y-olds at ≤25th growth percentile., Conclusions: Using WHO growth standards and international reference values, this study provides a protocol for addressing nutrient shortfalls among 1- to 5-y-olds, which could be applied in country-specific population health., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition.)
- Published
- 2022
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14. Primary repair of multiligament knee injury with InternalBrace ligament augmentation.
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Paterson-Byrne PA, Wilson WT, Hopper GP, and MacKay GM
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- Female, Humans, Knee Joint diagnostic imaging, Knee Joint surgery, Transplantation, Autologous, Treatment Outcome, Anterior Cruciate Ligament Injuries surgery, Collateral Ligaments, Knee Dislocation surgery, Knee Injuries surgery
- Abstract
Multiligament injury of the knee usually occurs as a result of high-energy trauma causing tibiofemoral dislocation. These are rare but potentially limb-threatening injuries, frequently involving nerve or arterial damage and often leading to severe complex instability. Management generally favours surgical reconstruction of the affected ligaments, with controversy regarding optimal treatment. We present a severe multiligament knee injury (Schenk classification KD-IV involving both cruciate and both collateral ligaments) in a competitive showjumper. A combined arthroscopic/open technique of single-stage surgical repair and suture augmentation was used, repairing all affected ligaments. The patient made an excellent recovery, returning to work after 12 weeks and riding after 22 weeks. After 5-year follow-up, she has regained her previous level of competition without subsequent injury. Multiligament repair with suture augmentation is a viable approach to the management of knee dislocation injuries. We propose that this could provide superior outcomes to traditional reconstruction techniques using autograft or synthetic reconstruction., Competing Interests: Competing interests: GMM is a paid consultant for Arthrex, whose products were used in this case., (© BMJ Publishing Group Limited 2022. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2022
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15. Nucleophilicities and Nucleofugalities of Thio- and Selenoethers.
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Maji B, Duan XH, Jüstel PM, Byrne PA, Ofial AR, and Mayr H
- Abstract
Rate constants for the reactions of dialkyl chalcogenides with laser flash photolytically generated benzhydrylium ions have been measured photometrically to integrate them into the comprehensive benzhydrylium-based nucleophilicity scale. Combining these rate constants with the previously reported equilibrium constants for the same reactions provided the corresponding Marcus intrinsic barriers and made it possible to quantify the leaving group abilities (nucleofugalities) of dialkyl sulfides and dimethyl selenide. Due to the low intrinsic barriers, dialkyl chalcogenides are fairly strong nucleophiles (comparable to pyridine and N-methylimidazole) as well as good nucleofuges; this makes them useful group-transfer reagents., (© 2021 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)
- Published
- 2021
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16. Impact of COVID-19 on motor vehicle injuries and fatalities in older adults in Ontario, Canada.
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Rapoport MJ, Chee JN, Aljenabi N, Byrne PA, Naglie G, Ilari F, Elzohairy Y, Vingilis E, and Mulsant BH
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- Accidents, Traffic, Adolescent, Adult, Aged, Aged, 80 and over, Humans, Motor Vehicles, North America, Ontario epidemiology, Pandemics, SARS-CoV-2, Young Adult, COVID-19, Wounds and Injuries epidemiology
- Abstract
Background: Older adults constitute the group most vulnerable to COVID-19 mortality. As a result, in North America and elsewhere, older adults have been strongly advised to shelter in place. Older adults also represent the fastest growing segment of licensed drivers., Objective: We examined the change in injuries and fatalities sustained by younger and older drivers and pedestrians during the first month of the COVID-19 pandemic. We hypothesized that adults ages 80 years and over would have a proportionally larger reduction than the other drivers and pedestrians., Methods: Using a cohort design, we compared the proportion of drivers and pedestrians involved in injuries and fatalities attributable to individuals aged 80 years and over, as recorded in the Ministry of Transportation of Ontario (Canada) database, between the 30 days prior to shelter-in-place related to the COVID-19 pandemic and the subsequent 30 days. By way of comparison, we conducted a similar comparison for younger age cohorts (16-24 years, 25-34 years, 35-54 years, 55-64 years, and 65-79 years)., Results: Drivers aged 80 years and over represented 21 per 1000 injuries and fatalities in the 30 days prior to March 17, 2020 (95 % CI: 15-29), and 8 per 1000 injuries and fatalities in the 30 days beginning on that date (95 % CI: 2-20), a 64.7 % reduction (exp (β) post 0.353, 95 % CI 0.105-0.892). Drivers in the 35-54 year age range underwent a significant but smaller reduction of 22.9 %; no significant changes were seen for drivers in other age groups, or for pedestrians of any age., Conclusions and Relevance: The physical distancing measures that aimed to reduce the spread of COVID-19 resulted in a marked reduction in driver injuries and fatalities in the oldest old, illustrating the impact of physical distancing recommendations in this population. The excess mortality burden faced by the oldest adults during the COVID-19 pandemic, by direct exposure to the virus, may be indirectly mitigated by the reduction in road-related deaths in this cohort., (Copyright © 2021 Elsevier Ltd. All rights reserved.)
- Published
- 2021
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17. Addendum - Coronavirus Disease 2019: What Could Be the Effects on Road Safety?
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Vingilis E, Johnson J, Rapoport MJ, Beirness D, Boase P, Byrne PA, Jonah B, Mann RE, Seeley J, Wickens CM, and Wiesenthal DL
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- 2021
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18. Competition between N and O: use of diazine N -oxides as a test case for the Marcus theory rationale for ambident reactivity.
- Author
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Sheehy KJ, Bateman LM, Flosbach NT, Breugst M, and Byrne PA
- Abstract
The preferred site of alkylation of diazine N -oxides by representative hard and soft alkylating agents was established conclusively using the
1 H-15 N HMBC NMR technique in combination with other NMR spectroscopic methods. Alkylation of pyrazine N -oxides ( 1 and 2 ) occurs preferentially on nitrogen regardless of the alkylating agent employed, while O -methylation of pyrimidine N -oxide ( 3 ) is favoured in its reaction with MeOTf. As these outcomes cannot be explained in the context of the hard/soft acid/base (HSAB) principle, we have instead turned to Marcus theory to rationalise these results. Marcus intrinsic barriers (Δ G‡ 0 ) and Δr G ° values were calculated at the DLPNO-CCSD(T)/def2-TZVPPD/SMD//M06-2X-D3/6-311+G(d,p)/SMD level of theory for methylation reactions of 1 and 3 by MeI and MeOTf, and used to derive Gibbs energies of activation (Δ G‡ ) for the processes of N - and O -methylation, respectively. These values, as well as those derived directly from the DFT calculations, closely reproduce the observed experimental N - vs. O -alkylation selectivities for methylation reactions of 1 and 3 , indicating that Marcus theory can be used in a semi-quantitative manner to understand how the activation barriers for these reactions are constructed. It was found that N -alkylation of 1 is favoured due to the dominant contribution of Δr G ° to the activation barrier in this case, while O -alkylation of 3 is favoured due to the dominant contribution of the intrinsic barrier (Δ G‡ 0 ) for this process. These results are of profound significance in understanding the outcomes of reactions of ambident reactants in general., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2020
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19. Repair of the ulnar collateral ligament of the elbow with internal brace augmentation: a 5-year follow-up.
- Author
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Wilson WT, Hopper GP, Byrne PA, and MacKay GM
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- Adult, Collateral Ligament, Ulnar diagnostic imaging, Elbow Joint diagnostic imaging, Humans, Joint Dislocations surgery, Magnetic Resonance Imaging, Male, Range of Motion, Articular, Plastic Surgery Procedures methods, Return to Sport, Collateral Ligament, Ulnar injuries, Football injuries, Elbow Injuries
- Abstract
The ulnar collateral ligament (UCL) is the primary restraint to valgus angulation at the elbow. Injury to the UCL is increasingly common and can lead to instability, especially in athletes involved in overhead throwing. Conventional treatment is reconstruction using tendon autograft but performance levels are often restricted after long periods of rehabilitation. Modern surgical techniques have led to renewed interest in repair of the ligament, with the aim of restoring native anatomy. This has the benefit of retained proprioception and no graft harvest morbidity. Furthermore, augmentation of the repair with an Internal Brace protects the healing ligament, while allowing early rehabilitation and accelerated return to play. Here we present the first patient treated with this technique who achieved excellent recovery with return to college level American Football after 4 months. Five years later he has good elbow function and plays at the same level., Competing Interests: Competing interests: GMM is a consultant for Arthrex (see attached COI form)., (© BMJ Publishing Group Limited 2018. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2018
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20. Acromioclavicular Joint Stabilisation Using the Internal Brace Principle.
- Author
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Byrne PA, Hopper GP, Wilson WT, and Mackay GM
- Subjects
- Adult, Football, Humans, Male, Acromioclavicular Joint surgery, Athletic Injuries surgery, Minimally Invasive Surgical Procedures methods, Orthopedic Procedures methods, Shoulder Injuries surgery
- Abstract
Introduction: Injury of the acromioclavicular joint (AC joint) is one of the most common conditions affecting the shoulder girdle in athletes, particularly in contact sports. It is generally agreed that surgical management provides superior outcomes in high-grade injuries (Rockwell Grades IV-VI), with nonoperative management preferred in low-grade injuries (Grades I-II). Controversy still exists regarding the optimal treatment for Grade III injuries, with various sources reporting quicker return to activity and reduced complications with nonoperative management, but superior long-term function and satisfaction in cases managed surgically. Mean predicted return to sporting action in surgical cases varies in the literature from four months to 9.5 months.
- Published
- 2018
21. Patient Factors Associated with Shorter Length of Stay Following Total Hip Arthroplasty-A Retrospective Cohort Study.
- Author
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Byrne PA, Gupta S, Hopper GP, Deakin AH, Roberts JL, and Kinninmonth AWG
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- Adult, Aged, Aged, 80 and over, Female, Humans, Male, Middle Aged, Retrospective Studies, Arthroplasty, Replacement, Hip statistics & numerical data, Length of Stay statistics & numerical data
- Abstract
Introduction: Total hip arthroplasty (THA) is an increasingly common procedure in the United Kingdom and incurs vast costs, with a mean length of stay (LOS) of 5.5 days. Reducing LOS plays a key role in improving cost-effectiveness, morbidity, and patient satisfaction following many orthopaedic procedures. The aim of this study was to identify attributes in patients with the shortest LOS following THA, with a view to targeting those with the potential for early discharge., Materials and Methods: 1280 THA cases over one year at one institution were reviewed in a retrospective case note study. Of these, 131 patients had LOS=2 days. Various factors (age, gender, American Society of Anesthesiologists (ASA) score, primary diagnosis, body mass index (BMI), socio-economic status) were compared between this group and the rest of the cohort. Further characteristics of the short LOS group were also explored to identify trends for future study., Results: Lower age, male gender, and low ASA grade were significantly associated with the short LOS group (all p<0.001). BMI, primary diagnosis, and socioeconomic status showed no significant differences. Short LOS patients were also noted to have few comorbidities, family at home, and independent transport., Conclusion: Younger age, male gender, and lower ASA grade are associated with early discharge following THA, and could be used to identify patients suitable for early discharge.
- Published
- 2017
22. Why Are Vinyl Cations Sluggish Electrophiles?
- Author
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Byrne PA, Kobayashi S, Würthwein EU, Ammer J, and Mayr H
- Abstract
The kinetics of the reactions of the vinyl cations 2 [Ph
2 C═C+ -(4-MeO-C6 H4 )] and 3 [Me2 C═C+ -(4-MeO-C6 H4 )] (generated by laser flash photolysis) with diverse nucleophiles (e.g., pyrroles, halide ions, and solvents containing variable amounts of water or alcohol) have been determined photometrically. It was found that the reactivity order of the nucleophiles toward these vinyl cations is the same as that toward diarylcarbenium ions (benzhydrylium ions). However, the reaction rates of vinyl cations are affected only half as much by variation of the nucleophiles as those of the benzhydrylium ions. For that reason, the relative reactivities of vinyl cations and benzhydrylium ions depend strongly on the nature of the nucleophiles. It is shown that vinyl cations 2 and 3 react, respectively, 227 and 14 times more slowly with trifluoroethanol than the parent benzhydrylium ion (Ph)2 CH+ , even though in solvolysis reactions (80% aqueous ethanol at 25 °C) the vinyl bromides leading to 2 and 3 ionize much more slowly (half-lives 1.15 yrs and 33 days) than (Ph)2 CH-Br (half-life 23 s). The origin of this counterintuitive phenomenon was investigated by high-level MO calculations. We report that vinyl cations are not exceptionally high energy intermediates, and that high intrinsic barriers for the sp2 ⇌ sp rehybridizations account for the general phenomenon that vinyl cations are formed slowly by solvolytic cleavage of vinyl derivatives, and are also consumed slowly by reactions with nucleophiles.- Published
- 2017
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23. Knotless Repair of Achilles Tendon Rupture in an Elite Athlete: Return to Competition in 18 Weeks.
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Byrne PA, Hopper GP, Wilson WT, and Mackay GM
- Subjects
- Achilles Tendon injuries, Adult, Athletic Injuries diagnostic imaging, Athletic Injuries surgery, Early Ambulation, Follow-Up Studies, Humans, Injury Severity Score, Male, Minimally Invasive Surgical Procedures methods, Orthopedic Procedures methods, Postoperative Care methods, Range of Motion, Articular physiology, Recovery of Function, Rupture diagnostic imaging, Tendon Injuries diagnostic imaging, Time Factors, Treatment Outcome, Achilles Tendon surgery, Return to Sport, Rupture surgery, Suture Techniques, Tendon Injuries surgery
- Abstract
Rupture of the Achilles tendon is an increasingly common injury, particularly in physically active males, and current evidence favors minimally invasive surgical repair. We describe the case of a 36-year-old male elite bobsled athlete with complete rupture of the Achilles tendon. He was treated with surgical repair of the ruptured tendon using an innovative, minimally invasive procedure based on an internal bracing concept and was able to undergo early mobilization and aggressive physiotherapy rehabilitation. His recovery was such that he returned to training at 13 weeks postoperatively and participated in an international competition at 18 weeks, winning a World Cup silver medal. He subsequently raced at the 2014 Winter Olympic Games at 29 weeks after surgery. At >2 years since his injury, he has experienced no complications or reinjury. This represents an exceptional recovery that far exceeds the standard expected for such injuries. The use of this technique for athletes could enable accelerated return to sporting activity and attainment of their preinjury activity levels., (Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.)
- Published
- 2017
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24. Anterior Cruciate Ligament Repair with Internal Brace Ligament Augmentation.
- Author
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Wilson WT, Hopper GP, Byrne PA, and MacKay GM
- Subjects
- Anterior Cruciate Ligament, Humans, Treatment Outcome, Anterior Cruciate Ligament Injuries surgery, Anterior Cruciate Ligament Reconstruction methods, Suture Anchors
- Abstract
Background: Anterior cruciate ligament (ACL) reconstruction using tendon or ligament autograft is the gold standard surgical treatment for acute ruptures; however, this is still associated with subsequent problems and variable outcomes. Renewed interest in healing of injured ACL tissue has led to new surgical repair techniques., Case Description: We report the case of one of the first patients to undergo this novel procedure of ACL repair with internal bracing. An internal brace is a bridging concept using braided suture tape and knotless bone anchors to reinforce ligament strength. We followed the case of one of the first patients to undergo this technique over two years post-operatively., Outcomes: In this case, we present a good functional outcome along with radiographic and arthroscopic evidence of a healed ACL with normal appearance. The successful application of this technique has been demonstrated., Discussion: ACL repair techniques are re-emerging as a promising treatment option for acute proximal ruptures. Repair of the ACL can be performed successfully and has the advantage of retaining the natural proprioceptive fibres of the ligament. The internal brace acts as a secondary stabiliser after repair, which may allow accelerated rehabilitation and return to sports, whilst resisting injury recurrence when this is possible., Conclusions: Repair with internal bracing of the ACL provides an unobtrusive support which allows accelerated recovery. In this case, we demonstrate with radiographic and arthroscopic evidence, a robustly healed ACL after repair with internal bracing. Functional outcomes are excellent over two years following surgery and long term; retained proprioception may prevent re-injury and development of post-traumatic osteoarthritis.
- Published
- 2016
25. Vehicle impoundments improve drinking and driving licence suspension outcomes: Large-scale evidence from Ontario.
- Author
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Byrne PA, Ma T, and Elzohairy Y
- Subjects
- Humans, Interrupted Time Series Analysis, Ontario, Program Evaluation, Time Factors, Automobiles, Driving Under the Influence legislation & jurisprudence, Driving Under the Influence prevention & control, Licensure legislation & jurisprudence
- Abstract
Although vehicle impoundment has become a common sanction for various driving offences, large-scale evaluations of its effectiveness in preventing drinking and driving recidivism are almost non-existent in the peer-reviewed literature. One reason is that impoundment programs have typically been introduced simultaneously with other countermeasures, rendering it difficult to disentangle any observed effects. Previous studies of impoundment effectiveness conducted when such programs were implemented in isolation have typically been restricted to small jurisdictions, making high-quality evaluation difficult. In contrast, Ontario's "long-term" and "seven-day" impoundment programs were implemented in relative isolation, but with tight relationships to already existing drinking and driving suspensions. In this work, we used offence data produced by Ontario's population of over 9 million licensed drivers to perform interrupted time series analysis on drinking and driving recidivism and on rates of driving while suspended for drinking and driving. Our results demonstrate two key findings: (1) impoundment, or its threat, improves compliance with drinking and driving licence suspensions; and (2) addition of impoundment to suspension reduces drinking and driving recidivism, possibly through enhanced suspension compliance., (Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2016
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26. Program design for incentivizing ignition interlock installation for alcohol-impaired drivers: The Ontario approach.
- Author
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Ma T, Byrne PA, Bhatti JA, and Elzohairy Y
- Subjects
- Adult, Cohort Studies, Female, Humans, Longitudinal Studies, Male, Ontario, Program Evaluation, Recurrence, Accidents, Traffic prevention & control, Automobiles, Breath Tests instrumentation, Driving Under the Influence legislation & jurisprudence, Driving Under the Influence prevention & control, Motivation, Program Development, Protective Devices statistics & numerical data
- Abstract
Introduction: Drinking and driving is a major risk factor for traffic injuries. Although ignition interlocks reduce drinking and driving while installed, several issues undermine their implementation including delayed eligibility for installation, low installation once eligible, and a return to previous risk levels after de-installation. The Canadian province of Ontario introduced a "Reduced Suspension with Ignition Interlock Conduct Review" Program, significantly changing pre-existing interlock policy. The Program incentivizes interlock installation and an "early" guilty plea. It also attempts to reduce long-term recidivism through behavioural feedback and compliance-based removal. This evaluation is the first in assessing Program impact., Methods: Ontario drivers with a first time alcohol-impaired driving conviction between July 1, 2005 and November 25, 2014 comprised the study cohort. Longitudinal analyses, using interrupted time series and Cox regression, were conducted in which exposure was the Program and the outcomes were ignition interlock installation (N=30,200), pre-trial elapsed time (N=30,200), and post-interlock recidivism (N=9326)., Results: After Program implementation, installation rates increased by 54% and pre-trial elapsed time decreased by 146 days. Results suggest no effect on post-interlock recidivism., Conclusions: Through an incentive-based design, this Program was effective at addressing two commonly cited barriers to interlock implementation- delayed eligibility for installation and low installation once eligible. Results reveal that installation rates are responsive not only to incentivization but also to other external factors, thus presenting an opportunity for policy makers to find unique ways to influence interlock uptake, and thereby, to extend their deterrent effects to a larger subset of the population. This study is one of the few that do not rely on proxy measures of installation rate., (Copyright © 2016 Crown. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2016
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27. Ambident Reactivity of Acetyl- and Formyl-Stabilized Phosphonium Ylides.
- Author
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Byrne PA, Karaghiosoff K, and Mayr H
- Abstract
The kinetics and mechanism of the reactions of formyl-stabilized ylide Ph3P═CHCHO (1) and acetyl-stabilized ylide Ph3P═CHCOMe (2) with benzhydrylium ions (Ar2CH(+), 3) were investigated by UV-vis and NMR spectroscopy. As ambident nucleophiles, ylides 1 and 2 can react at oxygen as well as at the α-carbon. For some reactions, it was possible to determine the second-order rate constant for O-attack as well as for C-attack and to derive the nucleophile-specific parameters N and sN according to the correlation lg k (20 °C) = sN(E + N) for both nucleophilic sites. Generally, O-attack of benzhydrylium ions is faster than C-attack. However, the initially formed benzhydryloxyvinylphosphonium ions can only be observed by NMR spectroscopy when benzhydryl cations with high Lewis acidity are employed. In other cases, rearrangement to the thermodynamically more stable products arising from C-attack occurs. The results derived from our investigations are employed to rationalize the behavior of ambident nucleophiles 1 and 2 in reactions with carbon-centered electrophiles in general. It is shown that the principle of hard and soft acids and bases (HSAB) and the related Klopman-Salem concept of charge and orbital control lead to incorrect predictions of regioselectivity. We also show that the rate of the Wittig reaction of ylide 2 with aldehyde 14 is significantly faster than the rate of either C- or O-attack calculated using lg k (20 °C) = sN(E + N), thus indicating that the oxaphosphetane is formed by a concerted [2 + 2] cycloaddition.
- Published
- 2016
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- View/download PDF
28. The Mechanism of Phosphonium Ylide Alcoholysis and Hydrolysis: Concerted Addition of the O-H Bond Across the P=C Bond.
- Author
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Byrne PA and Gilheany DG
- Abstract
The previous work on the hydrolysis and alcoholysis reactions of phosphonium ylides is summarized and reviewed in the context of their currently accepted mechanisms. Several experimental facts relating to ylide hydrolysis and to salt and ylide alcoholysis are shown to conflict with those mechanisms. In particular, we demonstrate that the pKa values of water and alcohols are too high in organic media to bring about protonation of ylide. Therefore, we propose concerted addition of the water or alcohol O-H bond across the ylide P=C bond. In support of this, we provide NMR spectroscopic evidence for equilibrium between ylide and aclohol that does not require the involvement of phosphonium hydroxide. We report the first P-alkoxyphosphorane to be characterised by NMR spectroscopy that does not undergo exchange on an NMR timescale. Two-dimensional NMR spectroscopic techniques have been applied to the characterisation to P-alkoxyphosphoranes for the first time., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2016
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29. Evaluation of the general deterrence capacity of recently implemented (2009-2010) low and Zero BAC requirements for drivers in Ontario.
- Author
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Byrne PA, Ma T, Mann RE, and Elzohairy Y
- Subjects
- Automobile Driving legislation & jurisprudence, Driving Under the Influence prevention & control, Humans, Interrupted Time Series Analysis, Licensure legislation & jurisprudence, Ontario, Accidents, Traffic prevention & control, Alcohol Drinking blood, Blood Alcohol Content, Driving Under the Influence legislation & jurisprudence
- Abstract
The number of injuries and fatalities associated with drinking and driving continues to decline in the province of Ontario. However, this behavior remains as one of the major contributors to collision-related injuries and fatalities. Few large-scale studies of blood alcohol concentration (BAC) <0.08% limits exist in the literature, necessitating additional investigation. Here we evaluate the general deterrent effectiveness of three Ontario countermeasures implemented during 2009 and 2010, two of which impose lower allowable BAC on drivers in the province. Using ARIMA-based interrupted time-series analysis we found that Warn-range sanctions, which include immediate roadside suspension for the previously un-targeted BAC range of 0.05-0.08%, were associated with a 17% decrease in the number of people injured or killed in drinking and driving collisions (relative to the number injured or killed in other collisions). Similarly, we found that Zero BAC requirements newly applied to young drivers (<22y.o.) were associated with a reduction in the numbers of two other dissimilar drinking and driving sanctions received by young drivers (relative to the number of these sanctions received by non-young drivers). A roadside seven-day vehicle impoundment for BAC>0.08%, which was added to an already existing roadside 90-day license suspension, was not found to produce general deterrence. Taken together, our results suggest that sanctions which target previously untargeted groups, specifically via lower BAC requirements, are effective as general deterrents against drinking and driving., (Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2016
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30. Working in tandem: The contribution of remedial programs and roadside licence suspensions to drinking and driving deterrence in Ontario.
- Author
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Ma T, Byrne PA, Haya M, and Elzohairy Y
- Subjects
- Adult, Age Factors, Aged, Aged, 80 and over, Cohort Studies, Female, Humans, Interrupted Time Series Analysis, Male, Middle Aged, Ontario, Young Adult, Alcohol Drinking prevention & control, Automobile Driving standards, Automobile Driving statistics & numerical data, Driving Under the Influence prevention & control, Driving Under the Influence statistics & numerical data, Licensure standards, Safety Management standards
- Abstract
In 1998, Ontario implemented a remedial program called "Back On Track" (BOT) for individuals convicted of alcohol-impaired driving. Drivers convicted before October 2000 were exposed to a single-component program ("Edu BOT"); those convicted after participated in a multi-component program ("Full BOT"). We evaluated the impact of BOT, and the preceding 90-day roadside licence suspension, on drinking and driving recidivism, an outcome yet to be examined, using population-wide driver records. A Chi Square Test was used to compare the three-year cumulative incidence of recidivism between three historically-defined cohorts: No BOT, Edu BOT, and Full BOT. Stratified analyses by completion status and by age were also conducted. Analyses of the roadside suspension were conducted using an interrupted time series approach based on segmented Poisson/negative binomial regression. The roadside suspension was associated with a 65.2% reduction in drinking driving recidivism. In combination with indefinite suspensions for non-completion, the BOT program was also associated with a 21% decrease in drinking and driving recidivism in the three years following a CCC driving prohibition, from 8.5% to 6.7%. This reduction cannot be explained by pre-existing trends in recidivism. Conversion of the BOT program from the single-component version to the multi-component program further reduced the three-year cumulative incidence of recidivism to 5.5% (a total reduction of 35% from pre-BOT). Results provide strong converging evidence that remedial alcohol education/treatment programs in combination with other sanctions can produce substantial increases in road safety., (Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2015
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31. Quantifying Labial Strength and Function in Facial Paralysis: Effect of Targeted Lip Injection Augmentation.
- Author
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Starmer H, Lyford-Pike S, Ishii LE, Byrne PA, and Boahene KD
- Subjects
- Adult, Aged, Aged, 80 and over, Biomechanical Phenomena, Facial Muscles physiopathology, Female, Humans, Hyaluronic Acid administration & dosage, Lip drug effects, Male, Middle Aged, Pressure, Prospective Studies, Viscosupplements administration & dosage, Facial Paralysis physiopathology, Lip physiopathology, Muscular Dystrophies physiopathology
- Abstract
Importance: Facial muscle weakness from paralysis or muscle dystrophy can significantly affect lip strength and function. Lip muscle weakness may result in articulation difficulties and spillage of food, both of which are socially and functionally disruptive for patients. There are few quantitative data on the effect of facial paralysis on lip strength., Objectives: To quantify the effect of facial paralysis and muscular dystrophy on lip strength and evaluate the effectiveness of targeted lip injection augmentation., Design, Setting, and Participants: Analysis of patients at the Johns Hopkins Hospital between January 1, 2008, and July 31, 2014, presenting for treatment of lip incompetence due to facial paralysis and facial muscular dystrophy was prospectively undertaken. Patients who had undergone direct surgical lip procedures were excluded., Main Outcomes and Measures: Lip pressure measurements, anterior bolus spillage, and articulation of bilabial sounds before and after treatment were assessed by a single speech pathologist. Lip pressures were measured with the Iowa Oral Performance Instrument., Results: Twenty-two patients with unilateral facial paralysis were evaluated for this study. Three patients with facioscapulohumeral muscular dystrophy were also evaluated. In unilateral facial paralysis, central lip strength was reduced in all patients compared with sex-corrected normative data (mean [SD] central lip strength, 5.5 [2.5] kPa in females and 9.6 [4.6] kPa in males). Compared with the nonparalyzed side, labial strength on the paralyzed sided was reduced by 69%. After injection augmentation of the paralyzed side, labial strength improved across the entire lip. Mean lip strength improved by 0.7-fold in the central lip from 5.60 to 9.30 kPa (P = .009), by 1.4-fold on the paralyzed side from 2.2 to 5.33 kPa (P = .006), and by 0.4-fold on the unaffected side from 7.11 to 9.56 kPa (P = .12). Lip strength in the 3 patients with facioscapulohumeral muscular dystrophy were uniformly reduced across the entire lip and improved by 6- to 7-fold after injection augmentation. All patients were noted by the speech pathologist to have improved articulation of plosive sounds and decreased anterior bolus spillage after the injection., Conclusions and Relevance: Labial strength is reduced across the lip in patients with unilateral facial paralysis. The Iowa Oral Performance Instrument is an effective tool for measuring labial strength and can be use to evaluate the effectiveness of facial reanimation procedures. Injection augmentation of the lip is a simple and effective means of improving labial strength, bilabial sounds, and anterior spillage in patients with facial paralysis or facial muscular dystrophy., Level of Evidence: 3.
- Published
- 2015
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32. First ever observation of the intermediate of phosphonium salt and ylide hydrolysis: P-hydroxytetraorganophosphorane.
- Author
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Byrne PA, Ortin Y, and Gilheany DG
- Abstract
P-Hydroxytetraorganophosphorane, the long-postulated intermediate in phosphonium salt and ylide hydrolysis, has been observed and characterised by low temperature NMR, finally definitively establishing its involvement in these reactions. The results require modification of the previously accepted mechanism for ylide hydrolysis: P-hydroxytetraorganophosphorane is generated directly by 4-centre reaction of ylide with water.
- Published
- 2015
- Full Text
- View/download PDF
33. Visual targets aren't irreversibly converted to motor coordinates: eye-centered updating of visuospatial memory in online reach control.
- Author
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Thompson AA, Byrne PA, and Henriques DY
- Subjects
- Adult, Biomechanical Phenomena, Female, Humans, Male, Memory, Movement, Photic Stimulation, Saccades, Upper Extremity physiology, Young Adult, Psychomotor Performance, Space Perception
- Abstract
Counter to current and widely accepted hypotheses that sensorimotor transformations involve converting target locations in spatial memory from an eye-fixed reference frame into a more stable motor-based reference frame, we show that this is not strictly the case. Eye-centered representations continue to dominate reach control even during movement execution; the eye-centered target representation persists after conversion to a motor-based frame and is continuously updated as the eyes move during reach, and is used to modify the reach plan accordingly during online control. While reaches are known to be adjusted online when targets physically shift, our results are the first to show that similar adjustments occur in response to changes in representations of remembered target locations. Specifically, we find that shifts in gaze direction, which produce predictable changes in the internal (specifically eye-centered) representation of remembered target locations also produce mid-transport changes in reach kinematics. This indicates that representations of remembered reach targets (and visuospatial memory in general) continue to be updated relative to gaze even after reach onset. Thus, online motor control is influenced dynamically by both the external and internal updating mechanisms.
- Published
- 2014
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34. The modern interpretation of the Wittig reaction mechanism.
- Author
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Byrne PA and Gilheany DG
- Subjects
- Alkenes chemical synthesis, Betaine chemistry, Betaine metabolism, Cycloaddition Reaction, Organophosphorus Compounds chemistry, Alkenes chemistry
- Abstract
The mechanism of the Wittig reaction has long been a contentious issue in organic chemistry. Even now, more than 50 years after its announcement, its presentation in many modern undergraduate textbooks is either overly simplified or entirely inaccurate. In this review, we gather together the huge body of evidence that has been amassed to show that the Li salt-free Wittig reactions of non-stabilised, semi-stabilised and stabilised ylides all occur under kinetic control by a common mechanism in which oxaphosphetane (OPA) is the first-formed and only intermediate. The numerous recent significant additions to the subject - including computational studies and experimental material pertinent to both steps of the reaction (OPA formation and its decomposition) are discussed in detail, and the currently accepted explanations for the source of the stereoselectivity in Wittig reactions are given. We also present the other mechanistic proposals that have been made during the history of the Wittig reaction, and show how they are unable to account for all of the experimental evidence that is now available. Details of certain experimental facts to do with Wittig reactions in the presence of Li cation are also included, although the precise mechanistic details of such reactions are yet to be established conclusively. We make the case that a clear distinction should henceforth be made between the unknown "Li-present" and the now well-established "Li salt-free" Wittig mechanisms.
- Published
- 2013
- Full Text
- View/download PDF
35. When more is less: increasing allocentric visual information can switch visual-proprioceptive combination from an optimal to sub-optimal process.
- Author
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Byrne PA and Henriques DY
- Subjects
- Adult, Female, Functional Laterality physiology, Hand innervation, Humans, Male, Models, Biological, Photic Stimulation, Physical Stimulation, Predictive Value of Tests, Psychomotor Performance, Reproducibility of Results, Young Adult, Attention physiology, Proprioception physiology, Touch physiology, Visual Perception physiology
- Abstract
When reaching for an object in the environment, the brain often has access to multiple independent estimates of that object's location. For example, if someone places their coffee cup on a table, then later they know where it is because they see it, but also because they remember how their reaching limb was oriented when they placed the cup. Intuitively, one would expect more accurate reaches if either of these estimates were improved (e.g., if a light were turned on so the cup were more visible). It is now well-established that the brain tends to combine two or more estimates about the same stimulus as a maximum-likelihood estimator (MLE), which is the best thing to do when estimates are unbiased. Even in the presence of small biases, relying on the MLE rule is still often better than choosing a single estimate. For this work, we designed a reaching task in which human subjects could integrate proprioceptive and allocentric (landmark-relative) visual information to reach for a remembered target. Even though both of these modalities contain some level of bias, we demonstrate via simulation that our subjects should use an MLE rule in preference to relying on one modality or the other in isolation. Furthermore, we show that when visual information is poor, subjects do, indeed, combine information in this way. However, when we improve the quality of visual information, subjects counter-intuitively switch to a sub-optimal strategy that occasionally includes reliance on a single modality., (Copyright © 2012 Elsevier Ltd. All rights reserved.)
- Published
- 2013
- Full Text
- View/download PDF
36. Hand-related rather than goal-related source of gaze-dependent errors in memory-guided reaching.
- Author
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Dessing JC, Byrne PA, Abadeh A, and Crawford JD
- Subjects
- Adult, Female, Fixation, Ocular, Humans, Male, Photic Stimulation methods, Young Adult, Eye Movements physiology, Goals, Memory physiology, Psychomotor Performance physiology
- Abstract
Mechanisms for visuospatial cognition are often inferred directly from errors in behavioral reports of remembered target direction. For example, gaze-centered target representations for reach were first inferred from reach overshoots of target location relative to gaze. Here, we report evidence for the hypothesis that these gaze-dependent reach errors stem predominantly from misestimates of hand rather than target position, as was assumed in all previous studies. Subjects showed typical gaze-dependent overshoots in complete darkness, but these errors were entirely suppressed by continuous visual feedback of the finger. This manipulation could not affect target representations, so the suppressed gaze-dependent errors must have come from misestimates of hand position, likely arising in a gaze-dependent transformation of hand position signals into visual coordinates. This finding has broad implications for any task involving localization of visual targets relative to unseen limbs, in both healthy individuals and patient populations, and shows that response-related transformations cannot be ignored when deducing the sources of gaze-related errors.
- Published
- 2012
- Full Text
- View/download PDF
37. Unequivocal experimental evidence for a unified lithium salt-free Wittig reaction mechanism for all phosphonium Ylide types: reactions with β-heteroatom-substituted aldehydes are consistently selective for cis-oxaphosphetane-derived products.
- Author
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Byrne PA and Gilheany DG
- Abstract
The true course of the lithium salt-free Wittig reaction has long been a contentious issue in organic chemistry. Herein we report an experimental effect that is common to the Wittig reactions of all of the three major phosphonium ylide classes (non-stabilized, semi-stabilized, and stabilized): there is consistently increased selectivity for cis-oxaphosphetane and its derived products (Z-alkene and erythro-β-hydroxyphosphonium salt) in reactions involving aldehydes bearing heteroatom substituents in the β-position. The effect operates with both benzaldehydes and aliphatic aldehydes and is shown not to operate in the absence of the heteroatom substituent on the aldehyde. The discovery of an effect that is common to reactions of all ylide types strongly argues for the operation of a common mechanism in all Li salt-free Wittig reactions. In addition, the results are shown to be most easily explained by the [2+2] cycloaddition mechanism proposed by Vedejs and co-workers as supplemented by Aggarwal, Harvey, and co-workers, thus providing strong confirmatory evidence in support of that mechanism. Notably, a cooperative effect of ortho-substituents in the case of semi-stabilized ylides is confirmed and is accommodated by the cycloaddition mechanism. The effect is also shown to operate in reactions of triphenylphosphine-derived ylides and has previously been observed for reactions under aqueous conditions, thus for the first time providing evidence that kinetic control is in operation in both of these cases.
- Published
- 2012
- Full Text
- View/download PDF
38. Reach endpoint errors do not vary with movement path of the proprioceptive target.
- Author
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Jones SA, Byrne PA, Fiehler K, and Henriques DY
- Subjects
- Adolescent, Adult, Female, Humans, Male, Psychomotor Performance physiology, Vision, Ocular physiology, Young Adult, Hand physiology, Movement physiology, Proprioception physiology
- Abstract
Previous research has shown that reach endpoints vary with the starting position of the reaching hand and the location of the reach target in space. We examined the effect of movement direction of a proprioceptive target-hand, immediately preceding a reach, on reach endpoints to that target. Participants reached to visual, proprioceptive (left target-hand), or visual-proprioceptive targets (left target-hand illuminated for 1 s prior to reach onset) with their right hand. Six sites served as starting and final target locations (35 target movement directions in total). Reach endpoints do not vary with the movement direction of the proprioceptive target, but instead appear to be anchored to some other reference (e.g., body). We also compared reach endpoints across the single and dual modality conditions. Overall, the pattern of reaches for visual-proprioceptive targets resembled those for proprioceptive targets, while reach precision resembled those for the visual targets. We did not, however, find evidence for integration of vision and proprioception based on a maximum-likelihood estimator in these tasks.
- Published
- 2012
- Full Text
- View/download PDF
39. A convenient and mild chromatography-free method for the purification of the products of Wittig and Appel reactions.
- Author
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Byrne PA, Rajendran KV, Muldoon J, and Gilheany DG
- Abstract
A mild method for the facile removal of phosphine oxide from the crude products of Wittig and Appel reactions is described. Work-up with oxalyl chloride to generate insoluble chlorophosphonium salt (CPS) yields phosphorus-free products for a wide variety of these reactions. The CPS product can be further converted into phosphine.
- Published
- 2012
- Full Text
- View/download PDF
40. Interactions between gaze-centered and allocentric representations of reach target location in the presence of spatial updating.
- Author
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Byrne PA, Cappadocia DC, and Crawford JD
- Subjects
- Adult, Cues, Female, Humans, Male, Memory, Short-Term physiology, Photic Stimulation methods, Saccades physiology, Visual Fields physiology, Young Adult, Movement physiology, Space Perception physiology, Visual Perception physiology
- Abstract
Numerous studies have investigated the phenomenon of egocentric spatial updating in gaze-centered coordinates, and some have studied the use of allocentric cues in visually-guided movement, but it is not known how these two mechanisms interact. Here, we tested whether gaze-centered and allocentric information combine at the time of viewing the target, or if the brain waits until the last possible moment. To do this, we took advantage of the well-known fact that pointing and reaching movements show gaze-centered 'retinal magnification' errors (RME) that update across saccades. During gaze fixation, we found that visual landmarks, and hence allocentric information, reduces RME for targets in the left visual hemifield but not in the right. When a saccade was made between viewing and reaching, this landmark-induced reduction in RME only depended on gaze at reach, not at encoding. Based on this finding, we argue that egocentric-allocentric combination occurs after the intervening saccade. This is consistent with previous findings in healthy and brain damaged subjects suggesting that the brain updates early spatial representations during eye movement and combines them at the time of action., (Copyright © 2010 Elsevier Ltd. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
41. Infant heart transplantation after cardiac death: ethical and legal problems.
- Author
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Potts M, Byrne PA, and Evans DW
- Subjects
- Death, Ethics, Clinical, Ethics, Medical, Humans, Infant, Organ Transplantation ethics, Organ Transplantation legislation & jurisprudence, Beneficence, Heart Arrest, Heart Transplantation ethics, Heart Transplantation legislation & jurisprudence, Homicide ethics, Homicide legislation & jurisprudence, Physicians ethics, Tissue and Organ Harvesting ethics, Tissue and Organ Harvesting legislation & jurisprudence
- Abstract
The donation of organs after cardiac death in infants is not morally justified and should not be continued.
- Published
- 2010
42. Cue reliability and a landmark stability heuristic determine relative weighting between egocentric and allocentric visual information in memory-guided reach.
- Author
-
Byrne PA and Crawford JD
- Subjects
- Adult, Eye Movements physiology, Feedback, Female, Humans, Likelihood Functions, Male, Middle Aged, Models, Biological, Photic Stimulation methods, Psychomotor Performance physiology, Visual Fields physiology, Young Adult, Attention physiology, Cues, Memory physiology, Mental Processes physiology, Space Perception physiology
- Abstract
It is not known how egocentric visual information (location of a target relative to the self) and allocentric visual information (location of a target relative to external landmarks) are integrated to form reach plans. Based on behavioral data from rodents and humans we hypothesized that the degree of stability in visual landmarks would influence the relative weighting. Furthermore, based on numerous cue-combination studies we hypothesized that the reach system would act like a maximum-likelihood estimator (MLE), where the reliability of both cues determines their relative weighting. To predict how these factors might interact we developed an MLE model that weighs egocentric and allocentric information based on their respective reliabilities, and also on an additional stability heuristic. We tested the predictions of this model in 10 human subjects by manipulating landmark stability and reliability (via variable amplitude vibration of the landmarks and variable amplitude gaze shifts) in three reach-to-touch tasks: an egocentric control (reaching without landmarks), an allocentric control (reaching relative to landmarks), and a cue-conflict task (involving a subtle landmark "shift" during the memory interval). Variability from all three experiments was used to derive parameters for the MLE model, which was then used to simulate egocentric-allocentric weighting in the cue-conflict experiment. As predicted by the model, landmark vibration--despite its lack of influence on pointing variability (and thus allocentric reliability) in the control experiment--had a strong influence on egocentric-allocentric weighting. A reduced model without the stability heuristic was unable to reproduce this effect. These results suggest heuristics for extrinsic cue stability are at least as important as reliability for determining cue weighting in memory-guided reaching.
- Published
- 2010
- Full Text
- View/download PDF
43. Neonatal group B streptococcal infection related to breast milk.
- Author
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Byrne PA, Miller C, and Justus K
- Subjects
- Adult, Drug Resistance, Bacterial, Female, Humans, Infant, Newborn, Infant, Premature, Infectious Disease Transmission, Vertical prevention & control, Streptococcal Infections drug therapy, Treatment Outcome, Twins, Anti-Bacterial Agents therapeutic use, Milk, Human microbiology, Streptococcal Infections transmission, Streptococcus agalactiae isolation & purification
- Abstract
Group B streptococcus is currently the most common cause of sepsis and meningitis in newborns. How should mothers whose breast milk cultures show growth of this microorganism be managed regarding breastfeeding? This case study discusses the possible transfer of group B streptococcus to a preterm infant from mother's milk. It also describes the process that was taken to preserve the breastfeeding experience while the infant was treated. The questions provoked during this investigation prompted the authors to revise procedures in their special care nursery for dealing with infants and mothers presenting with signs of infection. In this case, providing treatment for the mother and infant and withholding breast milk from the infant until cultures were negative, while supporting the mother's milk supply, made it possible for this mother to continue to breastfeed.
- Published
- 2006
- Full Text
- View/download PDF
44. The impact of ballast water effluent on the Manila clam, Tapes semidecussatus.
- Author
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Byrne PA and O'Halloran J
- Subjects
- Animals, Environmental Monitoring methods, Ireland, Metals, Heavy analysis, Oils analysis, Seawater, Water Pollutants, Chemical analysis, Behavior, Animal, Bivalvia physiology, Geologic Sediments chemistry, Industrial Waste, Metals, Heavy toxicity, Oils toxicity, Water Pollutants, Chemical toxicity
- Abstract
The impact of ballast water discharge from an oil refinery in Whitegate Harbour, Co. Cork, Ireland to the Manila clam, Tapes semidecussatus, was investigated using a whole sediment bioassay. Bioassay organisms were exposed to surface sediments for a period of 21 days, including a reference and control sediment, collected from the vicinity of a ballast water discharge pipe. At the whole organism level, mortality and burrowing behaviour (assessed as time taken for organisms to burrow into the sediment) were used to determine the effects of exposure to test sediments. After 21 days, clam mortality was higher in surface sediments collected directly at the point of the ballast water discharge pipe than from all other test sediments assayed. After 10 days exposure to test sediments collected from the vicinity of the ballast water discharge pipe, the burrowing behaviour of animals was significantly different to the behaviour of animals exposed to uncontaminated sediments.
- Published
- 2004
- Full Text
- View/download PDF
45. "Brain death" is not death.
- Author
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Byrne PA and Weaver WF
- Subjects
- Humans, Brain Death diagnosis, Brain Death physiopathology, Death, Ethics, Medical, Psychophysiology
- Published
- 2004
46. Bioethics and the scientific challenge of the third millennium: to defend life, obey God and His natural laws.
- Author
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Byrne PA
- Subjects
- Brain Death, Embryo Research, Humans, Personhood, Reproductive Techniques, Assisted, Value of Life, Bioethics, Catholicism
- Published
- 1999
- Full Text
- View/download PDF
47. Consciousness in congenitally decorticate children: developmental vegetative state as self-fulfilling prophecy.
- Author
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Shewmon DA, Holmes GL, and Byrne PA
- Subjects
- Brain diagnostic imaging, Brain Diseases diagnostic imaging, Child, Female, Humans, Male, Tomography, X-Ray Computed, Brain abnormalities, Brain Diseases congenital, Consciousness physiology, Persistent Vegetative State physiopathology
- Abstract
According to traditional neurophysiological theory, consciousness requires neocortical functioning, and children born without cerebral hemispheres necessarily remain indefinitely in a developmental vegetative state. Four children between 5 and 17 years old are reported with congenital brain malformations involving total or near-total absence of cerebral cortex but who, nevertheless, possessed discriminative awareness: for example, distinguishing familiar from unfamiliar people and environments, social interaction, functional vision, orienting, musical preferences, appropriate affective responses, and associative learning. These abilities may reflect 'vertical' plasticity of brainstem and diencephalic structures. The relative rarity of manifest consciousness in congenitally decorticate children could be due largely to an inherent tendency of the label 'developmental vegetative state' to become a self-fulfilling prophecy.
- Published
- 1999
- Full Text
- View/download PDF
48. Why the NHS should fund infertility services.
- Author
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Byrne PA, Lewis SE, Traub AI, and McClure N
- Subjects
- Humans, Needs Assessment economics, Northern Ireland, Financing, Government economics, Health Care Rationing economics, Infertility diagnosis, Infertility therapy, Reproductive Techniques economics, State Medicine economics
- Published
- 1999
49. "Brain death" is false.
- Author
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Byrne PA and Rinkowski GM
- Subjects
- Goals, Human Rights, Humans, Individuality, Medicine, Personhood, Reference Standards, Value of Life, Brain Death, Christianity, Death
- Published
- 1999
- Full Text
- View/download PDF
50. Health care decisions.
- Author
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Byrne PA
- Subjects
- Advance Directives, Catholicism, Humans, Physicians, Proxy, Suicide, Assisted, Decision Making, Euthanasia, Passive, Life Support Care
- Published
- 1998
- Full Text
- View/download PDF
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