29 results on '"Andrew, Porter"'
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2. High-affinity antibodies specific to the core region of the tau protein exhibit diagnostic and therapeutic potential for Alzheimer’s disease
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Mohammad Arastoo, Lewis K. Penny, Richard Lofthouse, Aya Abdallah, Anna Abrahamsson, Pietro Marini, Valeria Melis, Gernot Riedel, Charles R. Harrington, Claude M. Wischik, Andrew Porter, and Soumya Palliyil
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Alzheimer’s disease ,Tauopathy ,Tau protein ,Paired helical filament ,Monoclonal antibody ,Diagnostic ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 ,Neurology. Diseases of the nervous system ,RC346-429 - Abstract
Abstract Background Recent advances in blood-based biomarker discovery are paving the way for simpler, more accessible diagnostic tools that can detect early signs of Alzheimer’s disease (AD). Recent successes in the development of amyloid-targeting immunotherapy approaches mark an important advancement in providing new options for the treatment of AD. We have developed a set of high-affinity monoclonal antibodies (mAbs) to tau protein that have the potential as tools for diagnosis and treatment of AD. Methods Sheep were immunised with either full-length tau (1-441) or truncated paired helical filament (PHF)-core tau (297–391). A stringent bio-panning and epitope selection strategy, with a particular focus directed to epitopes within the disease-relevant PHF-core tau, was used to identify single-chain antibodies (scAbs). These scAbs were ranked by affinity for each epitope class, with leads converted to high-affinity mAbs. These antibodies and their potential utility were assessed by their performance in tau immunoassays, as well as their ability to prevent tau aggregation and propagation. Further characterisation of these antibodies was performed by immunohistochemical staining of brain sections and immuno-gold electronmicroscopy of isolated PHFs. Results Our work resulted in a set of high-affinity antibodies reacting with multiple epitopes spanning the entire tau protein molecule. The tau antibodies directed against the core tau unit of the PHF inhibited pathological aggregation and seeding using several biochemical and cell assay systems. Through staining of brain sections and PHFs, the panel of antibodies revealed which tau epitopes were available, truncated, or occluded. In addition, highly sensitive immunoassays were developed with the ability to distinguish between and quantify various tau fragments. Conclusion This article introduces an alternative immunodiagnostic approach based on the concept of a “tauosome” – the diverse set of tau fragments present within biological fluids. The development of an antibody panel that can distinguish a range of different tau fragments provides the basis for a novel approach to potential diagnosis and monitoring of disease progression. Our results further support the notion that tau immunotherapy targeting the PHF-core needs to combine appropriate selection of both the target epitope and antibody affinity to optimise therapeutic potential.
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- 2024
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3. The Impact of a Virtual Coaching Program to Improve Instructional Alignment to State Standards
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Toni M. Smith, Michael S. Garet, Mengli Song, Drew Atchison, and Andrew Porter
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This study assesses the impact of a 2-year virtual coaching program on teacher and student outcomes. The program - Feedback on Alignment and Support for Teachers (FAST) - was intended to deepen teachers' understanding of their state's standards and improve the alignment of their instruction with the standards. Relying on a multisite school-level randomized controlled trial, we assessed the impact of the FAST program in fourth-grade math and fifth-grade English language arts (ELA). We found that the program had a positive impact on the alignment of teachers' instruction with state standards for both math and ELA teachers (effect sizes = 0.70 and 0.40, respectively), although the impact was statistically significant only for math teachers. In contrast to a growing body of evidence on the benefits of instructional coaching, the program's impact on student achievement, was in the negative direction for both fourth-grade mathematics and fifth-grade ELA (effect sizes = -0.07 and -0.10, respectively), although the impact on achievement was statistically significant only for ELA. These results suggest that improving instructional alignment alone may not be sufficient for improving student achievement.
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- 2024
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4. Implementation of problem-based learning modules in an introduction to public health course
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Yui Matsuda, Ashley Falcon, Andrew Porter, Aaron Royer, Leah Mohnkern, Diana Vergara, and Yesenia Valiente
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problem-based learning ,public health ,undergraduate ,active learning ,education ,students ,Public aspects of medicine ,RA1-1270 - Abstract
IntroductionWith traditional lecture-based learning methods often criticized for their limited ability to foster critical thinking and cognitive engagement, problem-based learning (PBL) has emerged as a promising alternative. This research investigates the impact of PBL on student learning outcomes, specifically focusing on the development of higher-order thinking skills, communication, growth mindset, and metacognitive abilities.MethodsPBL was implemented in an undergraduate public health course at a private university in the southeast US. The study was conducted in the Spring of 2022 using a convergent mixed-methods approach. Quantitative data were derived from university-wide Quality Enhancement Plan surveys and a course-specific PBL survey, which were analyzed using Repeated Measures ANOVA to assess changes in student perceptions over time. Additionally, qualitative data from open-ended survey questions were analyzed through thematic analysis, providing deeper insights into the students’ experiences and perceptions of PBL.ResultsResults indicated significant improvements in student communication skills, growth mindset, and metacognitive abilities across the semester. The thematic analysis of qualitative responses corroborated these findings, revealing enhanced team collaboration, active engagement in problem-solving, and increased comfort with complex real-world issues.DiscussionThe findings contribute to the growing body of evidence supporting PBL and offer practical insights for implementing PBL in public health education. The study also highlights the need for institutional support in adopting innovative teaching methods like PBL, emphasizing faculty development, resource allocation, and curriculum design.
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- 2024
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5. Intraoperative Fluoroscopy Versus Navigation to Determine Cup Anteversion in Direct Anterior Total Hip Replacement: A Technical Trick for Obtaining 'True' Anteversion
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Filippo Romanelli, DO, Ian S. Hong, MD, Jibran A. Khan, DO, Andrew Porter, MD, Jaclyn M. Jankowski, DO, Frank A. Liporace, MD, and Richard S. Yoon, MD
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Total hip arthroplasty ,Direct anterior ,Intraoperative imaging ,Fluoroscopy ,Computer-assisted navigation ,Orthopedic surgery ,RD701-811 - Abstract
During acetabular cup positioning, intraoperative measurements of cup anteversion were taken using both fluoroscopy and navigation system. With the C-arm introduced at 40°, an anteroposterior view of the pelvis is taken. The C-arm is then centered over the hip, showing an anteverted cup with an approximate inclination of 40°. The axial C-arm is tilted away until the cup opening is visualized as a straight line, indicating that the beam of the fluoroscopy is aligned with the cup’s anteversion. The tilt angle on the C-arm and anteversion reading on the navigation workstation were recorded. The high degree of agreement between fluoroscopic and navigation measurement of acetabular cup anteversion supports the use of fluoroscopy in settings with limited access to navigation systems in direct anterior total hip arthroplasty.
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- 2024
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6. Nuclear alpha-synuclein is present in the human brain and is modified in dementia with Lewy bodies
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David J. Koss, Daniel Erskine, Andrew Porter, Pawel Palmoski, Hariharan Menon, Olivia G. J. Todd, Marta Leite, Johannes Attems, and Tiago F. Outeiro
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Alpha-synuclein ,Dementia with Lewy bodies ,Lewy body disease ,Synucleinopathies ,Nuclear pathology ,Neurology. Diseases of the nervous system ,RC346-429 - Abstract
Abstract Dementia with Lewy bodies (DLB) is pathologically defined by the cytoplasmic accumulation of alpha-synuclein (aSyn) within neurons in the brain. Predominately pre-synaptic, aSyn has been reported in various subcellular compartments in experimental models. Indeed, nuclear alpha-synuclein (aSynNuc) is evident in many models, the dysregulation of which is associated with altered DNA integrity, transcription and nuclear homeostasis. However, the presence of aSynNuc in human brain cells remains controversial, yet the determination of human brain aSynNuc and its pathological modification is essential for understanding synucleinopathies. Here, using a multi-disciplinary approach employing immunohistochemistry, immunoblot, and mass-spectrometry (MS), we confirm aSynNuc in post-mortem brain tissue obtained from DLB and control cases. Highly dependent on antigen retrieval methods, in optimal conditions, intra-nuclear pan and phospho-S129 positive aSyn puncta were observed in cortical neurons and non-neuronal cells in fixed brain sections and in isolated nuclear preparations in all cases examined. Furthermore, an increase in nuclear phospho-S129 positive aSyn immunoreactivity was apparent in DLB cases compared to controls, in both neuronal and non-neuronal cell types. Our initial histological investigations identified that aSynNuc is affected by epitope unmasking methods but present under optimal conditions, and this presence was confirmed by isolation of nuclei and a combined approach of immunoblotting and mass spectrometry, where aSynNuc was approximately tenfold less abundant in the nucleus than cytoplasm. Notably, direct comparison of DLB cases to aged controls identified increased pS129 and higher molecular weight species in the nuclei of DLB cases, suggesting putative pathogenic modifications to aSynNuc in DLB. In summary, using multiple approaches we provide several lines of evidence supporting the presence of aSynNuc in autoptic human brain tissue and, notably, that it is subject to putative pathogenic modifications in DLB that may contribute to the disease phenotype.
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- 2022
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7. Retinal pigment epithelium extracellular vesicles are potent inducers of age‐related macular degeneration disease phenotype in the outer retina
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Marzena Kurzawa‐Akanbi, Phillip Whitfield, Florence Burté, Pietro Maria Bertelli, Varun Pathak, Mary Doherty, Birthe Hilgen, Lina Gliaudelytė, Mark Platt, Rachel Queen, Jonathan Coxhead, Andrew Porter, Maria Öberg, Daniela Fabrikova, Tracey Davey, Chia Shyan Beh, Maria Georgiou, Joseph Collin, Veronika Boczonadi, Anetta Härtlova, Michael Taggart, Jumana Al‐Aama, Viktor I Korolchuk, Christopher M Morris, Jasenka Guduric‐Fuchs, David H Steel, Reinhold J Medina, Lyle Armstrong, and Majlinda Lako
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age‐related macular degeneration ,complement factor H ,extracellular vesicles ,human induced pluripotent stem cells ,retinal pigment epithelium ,photoreceptors ,Cytology ,QH573-671 - Abstract
Abstract Age‐related macular degeneration (AMD) is a leading cause of blindness. Vision loss is caused by the retinal pigment epithelium (RPE) and photoreceptors atrophy and/or retinal and choroidal angiogenesis. Here we use AMD patient‐specific RPE cells with the Complement Factor H Y402H high‐risk polymorphism to perform a comprehensive analysis of extracellular vesicles (EVs), their cargo and role in disease pathology. We show that AMD RPE is characterised by enhanced polarised EV secretion. Multi‐omics analyses demonstrate that AMD RPE EVs carry RNA, proteins and lipids, which mediate key AMD features including oxidative stress, cytoskeletal dysfunction, angiogenesis and drusen accumulation. Moreover, AMD RPE EVs induce amyloid fibril formation, revealing their role in drusen formation. We demonstrate that exposure of control RPE to AMD RPE apical EVs leads to the acquisition of AMD features such as stress vacuoles, cytoskeletal destabilization and abnormalities in the morphology of the nucleus. Retinal organoid treatment with apical AMD RPE EVs leads to disrupted neuroepithelium and the appearance of cytoprotective alpha B crystallin immunopositive cells, with some co‐expressing retinal progenitor cell markers Pax6/Vsx2, suggesting injury‐induced regenerative pathways activation. These findings indicate that AMD RPE EVs are potent inducers of AMD phenotype in the neighbouring RPE and retinal cells.
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- 2022
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8. Effects of Oxygen Flows and Annealing Temperatures on Optical, Electrical, and Structural Properties of Co-Sputtered In2O3-Ga2O3-Zn Thin Films
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Yih-Shing Lee, Sheng-Yu Zhao, Yuan-Zhe Lin, Glen Andrew Porter, and Tsung-Cheng Tien
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co-sputtering indium–gallium–zinc oxide (IGZO) film ,oxygen flow ,annealing temperature ,X-ray photoelectron spectra ,Crystallography ,QD901-999 - Abstract
This study investigated the effects of oxygen (O2) flow rates and annealing temperatures on optical, electrical, and structural properties of indium–gallium–zinc oxide (IGZO) film on glass substrates fabricated by using a co-sputtering system with two radio-frequency (RF) (In2O3 and Ga2O3) and one direct current (DC) (Zn) magnetron. The average transmittance and optical energy gap increased significantly when the oxygen flow rate was increased from 1 sccm to 3 sccm. An increased O2 flow during co-sputtering IGZO films caused the crystallinity of the InGaZn7O10 phase to increase, yielding a smoother and more uniform granular structure. The carrier mobility rose and the carrier concentration decreased with increasing O2 flow. The results of X-ray photoelectron spectra (XPS) analyses explained the impacts of the O2 flow rates and annealing temperatures on optical and electrical properties of the co-sputtered IGZO films. The optimum process conditions of the co-sputtered In2O3-Ga2O3-Zn films were revealed as an O2 flow rate of 3 sccm and an annealing temperature at 300 °C, which showed the largest average transmittance of 82.48%, a larger optical bandgap of 3.21 eV, and a larger carrier mobility of 7.01 cm2 V−1s−1. XPS results at various annealing temperatures indicated that the co-sputtered IGZO films with an O2 flow rate of 3 sccm have more stable chemical compositions among different annealing temperatures.
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- 2023
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9. Ultraviolet light-induced collagen degradation inhibits melanoma invasion
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Timothy Budden, Caroline Gaudy-Marqueste, Andrew Porter, Emily Kay, Shilpa Gurung, Charles H. Earnshaw, Katharina Roeck, Sarah Craig, Víctor Traves, Jean Krutmann, Patricia Muller, Luisa Motta, Sara Zanivan, Angeliki Malliri, Simon J. Furney, Eduardo Nagore, and Amaya Virós
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Science - Abstract
Ultraviolet radiation (UVR) increases melanoma incidence. Here, the authors report that UVR-damaged dermal fibroblasts upregulate MMP1 to degrade collagen which inhibits melanoma invasion and that aged primary melanomas in skin with degraded collagen have a better prognosis, while new collagen synthesis restores invasion and leads to death.
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- 2021
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10. Diacetyl and Other Ketones in e-Cigarette Aerosols: Some Important Sources and Contributing Factors
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Kevin McAdam, Gareth Waters, Serban Moldoveanu, Jennifer Margham, Anthony Cunningham, Carl Vas, Andrew Porter, and Helena Digard
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e-cigarette ,diacetyl ,flavors ,acetyl propionyl ,acetoin ,pyrolysis - gas chromatography ,Chemistry ,QD1-999 - Abstract
Background: Concerns over the presence of the diketones 2,4 butanedione (DA) and 2,3 pentanedione (AP) in e-cigarettes arise from their potential to cause respiratory diseases. Their presence in e-liquids is a primary source, but they may potentially be generated by glycerol (VG) and propylene glycol (PG) when heated to produce aerosols. Factors leading to the presence of AP, DA and acetoin (AC) in e-cigarette aerosols were investigated. We quantified direct transfer from e-liquids, examined thermal degradation of major e-liquid constituents VG, PG and 1,3 propanediol (1,3 PD) and the potential for AC, AP and DA production from sugars and flavor additives when heated in e-cigarettes.Method: Transfers of AC, AP and DA from e-liquids to e-cigarette aerosols were quantified by comparing aerosol concentrations to e-liquid concentrations. Thermal generation from VG, PG or 1,3 PD e-liquids was investigated by measuring AC, AP and DA emissions as a function of temperature in an e-cigarette. Thermal generation of AC, AP and DA from sugars was examined by aerosolising e-liquids containing sucrose, fructose or glucose in an e-cigarette. Pyrolytic formation of AP and DA from a range of common flavors was assessed using flash pyrolysis techniques.Results: AC transfer efficiency was >90%, while AP and DA were transferred less efficiently (65%) indicating losses during aerosolisation. Quantifiable levels of DA were generated from VG and PG, and to a lesser extent 1,3 PD at coil temperatures >300°C. Above 350°C AP was generated from VG and 1,3 PD but not PG. AC was not generated from major constituents, although low levels were generated by thermal reduction of DA. Aerosols from e-liquids containing sucrose contained quantifiable (>6 ng/puff) levels of DA at all sucrose concentrations tested, with DA emissions increasing with increasing device power and concentration. 1% glucose, fructose or sucrose e-liquids gave comparable DA emissions. Furanose ring compounds also generate DA and AP when heated to 250°C.Conclusions: In addition to less than quantitative direct transfer from the e-liquid, DA and AP can be present in the e-cigarette aerosol due to thermal decomposition reactions of glycols, sugars and furanonse ring flavors under e-cigarette operating conditions.
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- 2021
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11. The composition of contemporary American and Swedish smokeless tobacco products
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Kevin G. McAdam, Harriet Kimpton, Arif Faizi, Andrew Porter, and Brad Rodu
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Smokeless tobacco ,Snus ,Snuff ,Water measurement ,Moisture content ,Chemistry ,QD1-999 - Abstract
Abstract The major components of 70 brands of smokeless tobacco products (STPs) from Sweden and the US were determined to provide greater understanding of the general chemical composition of these products. Various styles of STPs were examined: loose and portion snus from Sweden, and chewing tobacco, dry snuff, moist snuff, hard pellet, soft pellet and plug from the US. The components analysed were major STP components such as water, nicotine, sugars, humectants, sodium ions, chloride ions and ash. The relative quantities of the components varied significantly between different styles of STP. The major component of moist snuff and Swedish loose snus is water. With Swedish portion snus water and pouch material comprise more than half of the product mass; with chewing tobaccos water and sugars comprise around 60% of the products. With these STPs, tobacco was a minor component (30–35%) of the product mass. By way of contrast, tobacco comprised the majority (around 70–90%) of the product mass with dry snuff, hard pellet and soft pellet products. Additives such as sugars, propylene glycol, glycerol, and sodium chloride comprised up to around 12% of the STPs, except for plug and chewing tobaccos where sugars comprised 15–30% by mass of the STP on average. Significant disagreements were found amongst alternative methods of determining water/moisture content for STPs. In particular the oven method, commonly used to determine moisture in tobacco, gave significantly higher values than the Karl Fischer water method when propylene glycol was present. Smaller but similar differences were found using the Near-Infrared method. Choice of measurement technique has important consequences for accuracy of toxicant levels when reporting on a dry-weight basis, a commonly used parameter in smokeless tobacco research and emerging regulatory standards. Conversion to a DWB was also found to produce a preferential bias between and within different STP categories in favour of drier products. These data provide greater understanding of differences in the compositions of contemporary smokeless tobacco products, and demonstrate challenges associated with conversion of actual product contents to dry weight basis values.
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- 2019
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12. Analysis of coumarin and angelica lactones in smokeless tobacco products
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Kevin McAdam, Trevor Enos, Carol Goss, Harriet Kimpton, Arif Faizi, Steve Edwards, Christopher Wright, Andrew Porter, and Brad Rodu
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Coumarin ,Angelica lactone ,Smokeless tobacco ,Snuff ,Snus ,Chemistry ,QD1-999 - Abstract
Abstract Differences in health risks between different styles of smokeless tobacco products (STPs) have prompted interest in their relative levels of toxic chemicals. We report here the development of methods for the analysis of STPs for coumarin and for α-angelica lactone (α-AL), both of which have been included in various published lists of tobacco toxicants. We have also determined the concentrations of these lactones in commercial STPs from the US and Sweden, representing 80–90% of the 2010 market share for all the major STP categories in these two countries: 65 products (plus two reference products) for coumarin and 66 commercial products for α-AL. For coumarin, methanol extracts of the STPs were analysed by HPLC/MS/MS. The lower limit of quantification (LOQ) and limit of detection (LOD) were, respectively, 100 and 30 ng coumarin/g of STP on a wet weight basis (WWB). Alpha-AL was determined via direct headspace GC/MS. The LOQ and LOD were 65 and 30 ng/g WWB respectively. Coumarin was detected In 3/33 Swedish snus, 5/13 US chewing tobaccos, 16/16 moist snuffs and 5/6 dry snuffs. Concentrations in those samples with quantifiable coumarin contents ranged from 186 to 1656 ng/g WWB. Concentrations of coumarin measured in this study were consistent with levels naturally found in tobacco. None of the STPs analysed would significantly contribute to coumarin exposure in consumers compared with dietary sources, and estimated exposure levels were 1000× lower than the European Food Safety Authority Tolerable Daily Intake. Hence the relevance of coumarin to the toxicity of STPs and its inclusion in the FDA’s list of harmful and potentially harmful compounds list is questionable. Measurements of α-AL in these STPs found that the majority did not have quantifiable contents, however, for three STPs concentrations of α-AL were above the LOQ (116–140 ng/g WWB) and for four other STPs concentrations of α-AL could be estimated between the LOD and LOQ. Beta-angelica lactone was tentatively identified in three of the STPs but the levels could not be reliably quantified. The levels of α-AL in tobacco products are reported here for the first time, but the relevance of α-AL to the toxicity of STPs is also highly questionable given that it has GRAS status as a permitted food additive.
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- 2018
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13. The identification of carbon dioxide mediated protein post-translational modifications
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Victoria L. Linthwaite, Joanna M. Janus, Adrian P. Brown, David Wong-Pascua, AnnMarie C. O’Donoghue, Andrew Porter, Achim Treumann, David R. W. Hodgson, and Martin J. Cann
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Science - Abstract
Carbon dioxide can interact with proteins to form carbamate post-translational modifications. Here, the authors developed a strategy to identify carbamate post-translational modifications by trapping carbon dioxide and subsequently identifying the carbamylated proteins.
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- 2018
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14. STEF/TIAM2-mediated Rac1 activity at the nuclear envelope regulates the perinuclear actin cap
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Anna Woroniuk, Andrew Porter, Gavin White, Daniel T. Newman, Zoi Diamantopoulou, Thomas Waring, Claire Rooney, Douglas Strathdee, Daniel J. Marston, Klaus M. Hahn, Owen J. Sansom, Tobias Zech, and Angeliki Malliri
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Science - Abstract
The perinuclear actin cap determines nuclear morphology but its regulation is currently poorly understood. Here, the authors find that an activator of the Rac1 GTPase, STEF/TIAM2, localises to the nuclear envelope and contributes to perinuclear actin and myosin tension, which in turn regulates the actin cap.
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- 2018
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15. An evaluation and model of the Chinese Kang system to improve indoor thermal comfort in northeast rural China – Part-2: Result analysis
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Zhai, Zhiqiang John, Yates, Andrew Porter, Duanmu, Lin, and Wang, Zongshan
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- 2015
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16. An evaluation and model of the Chinese Kang system to improve indoor thermal comfort in northeast rural China – Part-1: Model development
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(John) Zhai, Zhiqiang, Yates, Andrew Porter, Duanmu, Lin, and Wang, Zongshan
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- 2015
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17. Simultaneous multislice acquisition with multi-contrast segmented EPI for separation of signal contributions in dynamic contrast-enhanced imaging.
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Klaus Eickel, David Andrew Porter, Anika Söhner, Marc Maaß, Lutz Lüdemann, and Matthias Günther
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Medicine ,Science - Abstract
We present a method to efficiently separate signal in magnetic resonance imaging (MRI) into a base signal S0, representing the mainly T1-weighted component without T2*-relaxation, and its T2*-weighted counterpart by the rapid acquisition of multiple contrasts for advanced pharmacokinetic modelling. This is achieved by incorporating simultaneous multislice (SMS) imaging into a multi-contrast, segmented echo planar imaging (EPI) sequence to allow extended spatial coverage, which covers larger body regions without time penalty. Simultaneous acquisition of four slices was combined with segmented EPI for fast imaging with three gradient echo times in a preclinical perfusion study. Six female domestic pigs, German-landrace or hybrid-form, were scanned for 11 minutes respectively during administration of gadolinium-based contrast agent. Influences of reconstruction methods and training data were investigated. The separation into T1- and T2*-dependent signal contributions was achieved by fitting a standard analytical model to the acquired multi-echo data. The application of SMS yielded sufficient temporal resolution for the detection of the arterial input function in major vessels, while anatomical coverage allowed perfusion analysis of muscle tissue. The separation of the MR signal into T1- and T2*-dependent components allowed the correction of susceptibility related changes. We demonstrate a novel sequence for dynamic contrast-enhanced MRI that meets the requirements of temporal resolution (Δt < 1.5 s) and image quality. The incorporation of SMS into multi-contrast, segmented EPI can overcome existing limitations of dynamic contrast enhancement and dynamic susceptibility contrast methods, when applied separately. The new approach allows both techniques to be combined in a single acquisition with a large spatial coverage.
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- 2018
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18. Activation of RHO-1 in cholinergic motor neurons competes with dopamine signalling to control locomotion.
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Clara L Essmann, Katie R Ryan, Muna Elmi, Kimberley Bryon-Dodd, Andrew Porter, Andrew Vaughan, Rachel McMullan, and Stephen Nurrish
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Medicine ,Science - Abstract
The small GTPase RhoA plays a crucial role in the regulation of neuronal signalling to generate behaviour. In the developing nervous system RhoA is known to regulate the actin cytoskeleton, however the effectors of RhoA-signalling in adult neurons remain largely unidentified. We have previously shown that activation of the RhoA ortholog (RHO-1) in C. elegans cholinergic motor neurons triggers hyperactivity of these neurons and loopy locomotion with exaggerated body bends. This is achieved in part through increased diacylglycerol (DAG) levels and the recruitment of the synaptic vesicle protein UNC-13 to synaptic release sites, however other pathways remain to be identified. Dopamine, which is negatively regulated by the dopamine re-uptake transporter (DAT), has a central role in modulating locomotion in both humans and C. elegans. In this study we identify a new pathway in which RHO-1 regulates locomotory behaviour by repressing dopamine signalling, via DAT-1, linking these two pathways together. We observed an upregulation of dat-1 expression when RHO-1 is activated and show that loss of DAT-1 inhibits the loopy locomotion phenotype caused by RHO-1 activation. Reducing dopamine signalling in dat-1 mutants through mutations in genes involved in dopamine synthesis or in the dopamine receptor DOP-1 restores the ability of RHO-1 to trigger loopy locomotion in dat-1 mutants. Taken together, we show that negative regulation of dopamine signalling via DAT-1 is necessary for the neuronal RHO-1 pathway to regulate locomotion.
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- 2018
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19. Therapeutic Potential of Shark Anti-ICOSL VNAR Domains is Exemplified in a Murine Model of Autoimmune Non-Infectious Uveitis
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Marina Kovaleva, Katherine Johnson, John Steven, Caroline J. Barelle, and Andrew Porter
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variable domain of shark new antigen receptor ,single chain binding domain ,shark ,autoimmunity ,phage display ,biologic therapeutics ,Immunologic diseases. Allergy ,RC581-607 - Abstract
Induced costimulatory ligand (ICOSL) plays an important role in the activation of T cells through its interaction with the inducible costimulator, ICOS. Suppression of full T cell activation can be achieved by blocking this interaction and has been shown to be an effective means of ameliorating disease in models of autoimmunity and inflammation. In this study, we demonstrated the ability of a novel class of anti-ICOSL antigen-binding single domains derived from sharks (VNARs) to effectively reduce inflammation in a murine model of non-infectious uveitis. In initial selections, specific VNARs that recognized human ICOSL were isolated from an immunized nurse shark phage display library and lead domains were identified following their performance in a series of antigen selectivity and in vitro bioassay screens. High potency in cell-based blocking assays suggested their potential as novel binders suitable for further therapeutic development. To test this hypothesis, surrogate anti-mouse ICOSL VNAR domains were isolated from the same phage display library and the lead VNAR clone selected via screening in binding and ICOS/ICOSL blocking experiments. The VNAR domain with the highest potency in cell-based blocking of ICOS/ICOSL interaction was fused to the Fc portion of human IgG1 and was tested in vivo in a mouse model of interphotoreceptor retinoid-binding protein-induced uveitis. The anti-mICOSL VNAR Fc, injected systemically, resulted in a marked reduction of inflammation in treated mice when compared with untreated control animals. This approach inhibited disease progression to an equivalent extent to that seen for the positive corticosteroid control, cyclosporin A, reducing both clinical and histopathological scores. These results represent the first demonstration of efficacy of a VNAR binding domain in a relevant clinical model of disease and highlight the potential of VNARs for the treatment of auto-inflammatory conditions.
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- 2017
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20. Reconstructing Laomedon’s Reign in Homer: Olympiomachia, Poseidon’s Wall, and the Earlier Trojan War
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Andrew Porter
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History of Greece ,DF10-951 - Abstract
Homeric allusions to Laomedon, the walls of Troy, and the first Trojan War reflect a backstory of previous fighting among the Olympians, which helps to explain the Iliadic portrait of Zeus’s fear of insubordination among the other gods.
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- 2014
21. The Art of grid fields: Geometry of neuronal time
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Andrey eShilnikov and Andrew Porter Maurer
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grid cells ,navigation ,theta ,oscillators ,Phase resetting ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
The discovery of grid cells in the entorhinal cortex has both elucidated our understanding of spatial representations in the brain, and germinated a large number of theoretical models regarding the mechanisms of these cells’ striking spatial firing characteristics. These models cross multiple neurobiological levels that include intrinsic membrane resonance, dendritic integration, after hyperpolarization characteristics and attractor dynamics. Despite the breadth of the models, to our knowledge, parallels can be drawn between grid fields and other temporal dynamics observed in nature, much of which was described by Art Winfree and colleagues long before the initial description of grid fields. Using theoretical and mathematical investigations of oscillators, in a wide array of mediums far from the neurobiology of grid cells, Art Winfree has provided a substantial amount of research with significant and profound similarities. These theories provide specific inferences into the biological mechanisms and extraordinary resemblances across phenomenon. Therefore, this manuscript provides a novel interpretation on the phenomenon of grid fields, from the perspective of coupled oscillators, postulating that grid fields are the spatial representation of phase resetting curves in the brain. In contrast to prior models of gird cells, the current manuscript provides a sketch by which a small network of neurons, each with oscillatory components can operate to form grid cells, perhaps providing a unique hybrid between the competing attractor neural network and oscillatory interference models. The intention of this new interpretation of the data is to encourage novel testable hypotheses.
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- 2016
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22. Author Correction: The identification of carbon dioxide mediated protein post-translational modifications
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Victoria L. Linthwaite, Joanna M. Janus, Adrian P. Brown, David Wong-Pascua, AnnMarie C. O’Donoghue, Andrew Porter, Achim Treumann, David R. W. Hodgson, and Martin J. Cann
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Science - Abstract
The original version of this Article omitted the following from the Acknowledgements: ‘This work was support by EPSRC grant EP/K504336/1 and Leverhulme Trust grant RPG-2016-017.’ This has been corrected in both the PDF and HTML versions of the Article.
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- 2018
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23. TOP2B: The First Thirty Years
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Caroline A. Austin, Ka C. Lee, Rebecca L. Swan, Mushtaq M. Khazeem, Catriona M. Manville, Peter Cridland, Achim Treumann, Andrew Porter, Nick J. Morris, and Ian G. Cowell
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Topoisomerase II ,TOP2 ,Cell cycle ,cell biology ,transcription ,review ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
Type II DNA topoisomerases (EC 5.99.1.3) are enzymes that catalyse topological changes in DNA in an ATP dependent manner. Strand passage reactions involve passing one double stranded DNA duplex (transported helix) through a transient enzyme-bridged break in another (gated helix). This activity is required for a range of cellular processes including transcription. Vertebrates have two isoforms: topoisomerase IIα and β. Topoisomerase IIβ was first reported in 1987. Here we review the research on DNA topoisomerase IIβ over the 30 years since its discovery.
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- 2018
- Full Text
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24. Optimization of Solar Module Encapsulant Lamination by Optical Constant Determination of Ethylene-Vinyl Acetate
- Author
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Bing-Mau Chen, Cheng-Yu Peng, Ju-Lu Cho, and Glen Andrew Porter
- Subjects
Renewable energy sources ,TJ807-830 - Abstract
This investigation elucidates the physical properties of ethylene-vinyl acetate (EVA) used in the lamination process of module encapsulation and the module performance from the optical transmission to the photoelectric power. In module encapsulation, the effects of the lamination parameters on the module performance, transmittance, and stack adhesion have been considered as they were found to influence the reliability of the module. The determination of the optical constants of EVA may serve as a nondestructive analytical method for optimizing the module encapsulation, on the basis of its effects on the optical transmittance, gel content, peel strength, and performance power.
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- 2015
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25. The Art of Grid Fields: Geometry of Neuronal Time.
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Shilnikov, Andrey L. and Maurer, Andrew Porter
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GRID cells ,NEURONS ,ENTORHINAL cortex ,BRAIN ,NEUROBIOLOGY - Abstract
The discovery of grid cells in the entorhinal cortex has both elucidated our understanding of spatial representations in the brain, and germinated a large number of theoretical models regarding the mechanisms of these cells' striking spatial firing characteristics. These models cross multiple neurobiological levels that include intrinsic membrane resonance, dendritic integration, after hyperpolarization characteristics and attractor dynamics. Despite the breadth of the models, to our knowledge, parallels can be drawn between grid fields and other temporal dynamics observed in nature, much of which was described by Art Winfree and colleagues long before the initial description of grid fields. Using theoretical and mathematical investigations of oscillators, in a wide array of mediums far from the neurobiology of grid cells, Art Winfree has provided a substantial amount of research with significant and profound similarities. These theories provide specific inferences into the biological mechanisms and extraordinary resemblances across phenomenon. Therefore, this manuscript provides a novel interpretation on the phenomenon of grid fields, from the perspective of coupled oscillators, postulating that grid fields are the spatial representation of phase resetting curves in the brain. In contrast to prior models of gird cells, the current manuscript provides a sketch by which a small network of neurons, each with oscillatory components can operate to form grid cells, perhaps providing a unique hybrid between the competing attractor neural network and oscillatory interference models. The intention of this new interpretation of the data is to encourage novel testable hypotheses. [ABSTRACT FROM AUTHOR]
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- 2016
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26. The effects of geometric design on the performance of abrupt-tapered fiber Mach-Zehnder interferometers.
- Author
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Ting-Chieh Lu, Kuan-Yu Lou, Glen Andrew Porter, and Chen, Nan-Kuang
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- 2013
- Full Text
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27. Making Connections Between Research and Practice.
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Andrew Porter
- Published
- 2007
- Full Text
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28. Report on a national echocardiography quality-control exercise.
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Kevin F. Fox, Andrew Porter, Beth Unsworth, Tim Collier, Graham Leech, and Jamil Mayet
- Abstract
Aims To assess the feasibility of conducting a large-scale quality-control exercise on the echocardiographic grading of mitral regurgitation (MR). Methods and results One hundred and fifty-two practising cardiologist and sonographer echocardiographers attended a dedicated session within a national meeting and were asked to review echocardiographic images of five case studies and evaluate the severity of MR using a six-point scale. The groups overall evaluation was analysed together with the variation in grading of severity. The proportion of gradings of MR more than one grade either side of the mode was Conclusions Conducting a large-scale quality-control exercise in the assessment of mitral regurgitation is feasible. Overall results suggesting reasonable consistency in reporting may hide substantial clinically relevant variability. It is essential that increasing importance is attached to the development, conduct, and analysis of quality control within echocardiography if it is to maintain and extend its role as a key investigation for patients with heart disease. [ABSTRACT FROM AUTHOR]
- Published
- 2009
29. Multiple frequency audio signal communication as a mechanism for neurophysiology and video data synchronization.
- Author
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Topper, Nicholas C., Burke, Sara N., and Maurer, Andrew Porter
- Subjects
- *
NEUROPHYSIOLOGY , *SIGNAL processing , *VIDEO compression , *LIGHT emitting diodes , *PULSE width modulation transformers , *BIOLOGICAL adaptation , *COST effectiveness - Abstract
Background Current methods for aligning neurophysiology and video data are either prepackaged, requiring the additional purchase of a software suite, or use a blinking LED with a stationary pulse-width and frequency. These methods lack significant user interface for adaptation, are expensive, or risk a misalignment of the two data streams. New method A cost-effective means to obtain high-precision alignment of behavioral and neurophysiological data is obtained by generating an audio-pulse embedded with two domains of information, a low-frequency binary-counting signal and a high, randomly changing frequency. This enabled the derivation of temporal information while maintaining enough entropy in the system for algorithmic alignment. Results The sample to frame index constructed using the audio input correlation method described in this paper enables video and data acquisition to be aligned at a sub-frame level of precision. Comparisons with existing method Traditionally, a synchrony pulse is recorded on-screen via a flashing diode. The higher sampling rate of the audio input of the camcorder enables the timing of an event to be detected with greater precision. Conclusions While on-line analysis and synchronization using specialized equipment may be the ideal situation in some cases, the method presented in the current paper presents a viable, low cost alternative, and gives the flexibility to interface with custom off-line analysis tools. Moreover, the ease of constructing and implements this set-up presented in the current paper makes it applicable to a wide variety of applications that require video recording. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
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