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Sökning: WFRF:(Raval M)

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1.
  • 2021
  • swepub:Mat__t
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2.
  • Kanai, M, et al. (författare)
  • 2023
  • swepub:Mat__t
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3.
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4.
  • Aaron, F. D., et al. (författare)
  • Multi-leptons with high transverse momentum at HERA
  • 2009
  • Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479. ; :10
  • Tidskriftsartikel (refereegranskat)abstract
    • Events with at least two high transverse momentum leptons (electrons or muons) are studied using the H1 and ZEUS detectors at HERA with an integrated luminosity of 0.94 fb(-1). The observed numbers of events are in general agreement with the Standard Model predictions. Seven di- and tri-lepton events are observed in e(+)p collision data with a scalar sum of the lepton transverse momenta above 100 GeV while 1.94 +/- 0.17 events are expected. Such events are not observed in e(-)p collisions for which 1.19 +/- 0.12 are predicted. Total visible and differential di-electron and di-muon photoproduction cross sections are extracted in a restricted phase space dominated by photon-photon collisions.
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5.
  • Aaron, F. D., et al. (författare)
  • Events with an isolated lepton and missing transverse momentum and measurement of W production at HERA
  • 2010
  • Ingår i: Journal of High Energy Physics. - 1029-8479. ; 2010:3, s. 1-19
  • Tidskriftsartikel (refereegranskat)abstract
    • A search for events containing an isolated electron or muon and missing trans verse momentum produced in e(+/-)p collisions is performed with the H1 and ZEUS detectors at HERA. The data were taken in the period 1994-2007 and correspond to an integrated luminosity of 0.98 fb(-1). The observed event yields are in good overall agreement with the Standard Model prediction, which is dominated by single W production. In the e(+)p data, at large hadronic transverse momentum P-T(X) > 25GeV, a total of 23 events are observed compared to a prediction of 14.0 +/- 1.9. The total single W boson production cross section is measured as 1.06 +/- 0.16 (stat.) +/- 0.07 (sys.) pb, in agreement with an Standard Model (SM) expectation of 1.26 +/- 0.19 pb.
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6.
  • Aaron, F. D., et al. (författare)
  • Combined measurement and QCD analysis of the inclusive e(+/-)p scattering cross sections at HERA
  • 2010
  • Ingår i: Journal of High Energy Physics. - 1029-8479. ; :1
  • Tidskriftsartikel (refereegranskat)abstract
    • A combination is presented of the inclusive deep inelastic cross sections measured by the H1 and ZEUS Collaborations in neutral and charged current unpolarised e(+/-)p scattering at HERA during the period 1994-2000. The data span six orders of magnitude in negative four-momentum-transfer squared, Q(2), and in Bjorken x. The combination method used takes the correlations of systematic uncertainties into account, resulting in an improved accuracy. The combined data are the sole input in a NLO QCD analysis which determines a new set of parton distributions, HERAPDF1.0, with small experimental uncertainties. This set includes an estimate of the model and parametrisation uncertainties of the fit result.
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7.
  • Aaron, F. D., et al. (författare)
  • Combined inclusive diffractive cross sections measured with forward proton spectrometers in deep inelastic ep scattering at HERA
  • 2012
  • Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 72:10
  • Tidskriftsartikel (refereegranskat)abstract
    • A combination of the inclusive diffractive cross section measurements made by the H1 and ZEUS Collaborations at HERA is presented. The analysis uses samples of diffractive deep inelastic ep scattering data at a centre-of-mass energy root s = 318 GeV where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertainties are taken into account, resulting in an improved precision of the cross section measurement which reaches 6 % for the most precise points. The combined data cover the range 2.5 < Q(2) < 200 GeV2 in photon virtuality, 0.00035 < x(P) < 0.09 in proton fractional momentum loss, 0.09 < vertical bar t vertical bar < 0.55 GeV2 in squared four-momentum transfer at the proton vertex and 0.0018 < beta < 0.816 in beta = x/x(P), where x is the Bjorken scaling variable.
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8.
  • Abramowicz, H., et al. (författare)
  • Combination and QCD analysis of charm production cross section measurements in deep-inelastic ep scattering at HERA
  • 2013
  • Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 73:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Measurements of open charm production cross sections in deep-inelastic ep scattering at HERA from the H1 and ZEUS Collaborations are combined. Reduced cross sections sigma(c (c) over bar)(red) for charm production are obtained in the kinematic range of photon virtuality 2.5 <= Q(2) <= 2000 GeV2 and Bjorken scaling variable 3 . 10(-5) <= x <= 5 . 10(-2). The combination method accounts for the correlations of the systematic uncertainties among the different data sets. The combined charm data together with the combined inclusive deep-inelastic scattering cross sections from HERA are used as input for a detailed NLO QCD analysis to study the influence of different heavy flavour schemes on the parton distribution functions. The optimal values of the charm mass as a parameter in these different schemes are obtained. The implications on the NLO predictions for W-+/- and Z production cross sections at the LHC are investigated. Using the fixed flavour number scheme, the running mass of the charm quark is determined.
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9.
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10.
  • Zaborowski, AM, et al. (författare)
  • Microsatellite instability in young patients with rectal cancer: molecular findings and treatment response
  • 2022
  • Ingår i: The British journal of surgery. - : Oxford University Press (OUP). - 1365-2168 .- 0007-1323. ; 109:3, s. 251-255
  • Tidskriftsartikel (refereegranskat)abstract
    • In this study of 400 patients with early-onset rectal cancer, 12.5 per cent demonstrated microsatellite instability (MSI). MSI was associated with a reduced likelihood of nodal positivity, an increased rate of pathological complete response, and improved disease-specific survival.
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11.
  • Gibb, ACN, et al. (författare)
  • Creation of an Enhanced Recovery After Surgery (ERAS) Guideline for neonatal intestinal surgery patients: a knowledge synthesis and consensus generation approach and protocol study
  • 2018
  • Ingår i: BMJ open. - : BMJ. - 2044-6055. ; 8:12, s. e023651-
  • Tidskriftsartikel (refereegranskat)abstract
    • Enhanced Recovery After Surgery (ERAS) guidelines integrate evidence-based practices into multimodal care pathways designed to optimise patient recovery following surgery. The objective of this project is to create an ERAS protocol for neonatal abdominal surgery. The protocol will identify and attempt to bridge the gaps between current practices and best evidence. Our study is the first paediatric ERAS protocol endorsed by the International ERAS Society.MethodsA research team consisting of international clinical and family stakeholders as well as methodological experts have iteratively defined the scope of the protocol in addition to individual topic areas. A modified Delphi method was used to reach consensus. The second phase will include a series of knowledge syntheses involving a rapid review coupled with expert opinion. Potential protocol elements supported by synthesised evidence will be identified. The Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) system will be used to determine strength of recommendations and the quality of evidence. The third phase will involve creation of the protocol using a modified RAND/UCLA Appropriateness Method. Group consensus will be used to rate each element in relation to the quality of evidence supporting the recommendation and the appropriateness for guideline inclusion. This protocol will form the basis of a future implementation study.Ethics and disseminationThis study has been registered with the ERAS Society. Human ethics approval (REB 18–0579) is in place to engage patient families within protocol development. This research is to be published in peer-reviewed journals and will form the care standard for neonatal intestinal surgery.
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12.
  • Brindle, ME, et al. (författare)
  • Consensus Guidelines for Perioperative Care in Neonatal Intestinal Surgery: Enhanced Recovery After Surgery (ERAS®) Society Recommendations
  • 2020
  • Ingår i: World journal of surgery. - : Springer Science and Business Media LLC. - 1432-2323 .- 0364-2313. ; 44:8, s. 2482-2492
  • Tidskriftsartikel (refereegranskat)abstract
    • BackgroundEnhanced Recovery After Surgery (ERAS®) Society guidelines integrate evidence-based practices into multimodal care pathways that have improved outcomes in multiple adult surgical specialties. There are currently no pediatric ERAS®Society guidelines. We created an ERAS®guideline designed to enhance quality of care in neonatal intestinal resection surgery.MethodsA multidisciplinary guideline generation group defined the scope, population, and guideline topics. Systematic reviews were supplemented by targeted searching and expert identification to identify 3514 publications that were screened to develop and support recommendations. Final recommendations were determined through consensus and were assessed for evidence quality and recommendation strength. Parental input was attained throughout the process.ResultsFinal recommendations ranged from communication strategies to antibiotic use. Topics with poor-quality and conflicting evidence were eliminated. Several recommendations were combined. The quality of supporting evidence was variable. Seventeen final recommendations are included in the proposed guideline.DiscussionWe have developed a comprehensive, evidence-based ERAS guideline for neonates undergoing intestinal resection surgery. This guideline, and its creation process, provides a foundation for future ERAS guideline development and can ultimately lead to improved perioperative care across a variety of pediatric surgical specialties.
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14.
  • Forster, M., et al. (författare)
  • Assembly of Chiral Amino-Acids at Surfaces from a Single Molecule Perspective: Proline on Cu(110)
  • 2011
  • Ingår i: Topics in Catalysis. - : Springer Science and Business Media LLC. - 1572-9028 .- 1022-5528. ; 54:1-4, s. 13-19
  • Tidskriftsartikel (refereegranskat)abstract
    • We present a molecule-by-molecule mapping of an amino-acid monolayer on a Cu(110) surface in which individual molecular configuration, bonding and adsorption footprints are identified. This detailed mapping provides direct evidence that the (4 x 2) structures of enantiopure and racemic proline are governed by a strict heterochiral adsorption footprint template. For the racemic system this has an interesting consequence, namely that it leads to a 2-D random solid solution, a situation that is rarely encountered in 3-D.
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15.
  • Forster, M., et al. (författare)
  • Mapping Complex Chiral Adlayers: A Truly Random 2-D Solid Solution of (RS)-3-Pyrroline-2-Carboxylic Acid on Cu(110)
  • 2011
  • Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 115:4, s. 1180-1185
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • The characterization of chiral molecular adlayers remains a considerable challenge, ultimately requiring detailed knowledge of the molecular chirality, the chemical form, molecular orientation, and interaction with the surface for each molecule within the assembly. In this work, we show that the (4 x 2) organization of a racemic mixture of the amino acid derivative 3-pyrroline-2-carboxylic acid (PCA) on Cu(110) may be analyzed at the single-molecule level in which the molecular chirality and adsorption footprints of each molecule are identified. Such a detailed mapping reveals the surprising outcome that within the racemic (4 x 2) organization the adlayer does not form either the 2-D racemic compound or racemic conglomerate. Instead, both the molecular chirality and adsorption footprints are randomly distributed, creating a truly random solid solution in which both molecular chirality and footprint chirality are scrambled.
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16.
  • Forster, M., et al. (författare)
  • Probing Conformer and Adsorption Footprint Distributions at the Single-Molecule Level in a Highly Organised Amino-Acid Assembly of (S)-Proline on Cu(110)
  • 2009
  • Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 131:29, s. 10173-10181
  • Tidskriftsartikel (refereegranskat)abstract
    • Establishing the nanoscale details of organized amino acid assemblies at surfaces is a major challenge in the field of organic-inorganic interfaces. Here, we show that the dense (4 x 2) overlayer of the amino acid, (S)-proline on a Cu(110) surface can be explored at the single-molecule level by scanning tunneling microscopy (STM), reflection absorption infrared spectroscopy (RAIRS), and periodic density functional theory (DFT) calculations. The combination of experiment and theory, allied with the unique structural rigidity of proline, enables the individual conformers and adsorption footprints adopted within the organized assembly to be determined. Periodic DFT calculations find two energetically favorable molecular conformations, projecting mirror-image chiral adsorption footprints at the surface. These two forms can be experimentally distinguished since the positioning of the amino group within the pyrrolidine ring leads each chiral footprint and associated conformer to adopt very different ring orientations, producing distinct contrasts in the STM images. DFT modeling shows that the two conformers can generate eight possible (4 x 2) overlayers with a variety of adsorption footprint arrangements. STM images simulated for each structural model enables a direct comparison to be made with the experiment and narrows the (4 x 2) overlayer to one specific structural model in which the juxtaposition of molecules leads to the formation of one-dimensional hydrogen bonded prolate chains directed along the [1 (1) over bar0] direction.
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17.
  • Forster, M., et al. (författare)
  • Tailoring Homochirality at Surfaces: Going Beyond Molecular Handedness
  • 2011
  • Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 133:40, s. 15992-16000
  • Tidskriftsartikel (refereegranskat)abstract
    • Chirality can be bestowed upon a surface by the adsorption of molecules and is usually discussed in terms of the molecular handedness. However, the adsorption process often leads to a new manifestation of chirality in the form of the adsorption footprint, which can also be chiral and generate mirror-images in 2-D. Therefore, in describing the chirality of the interface, one must consider both the handedness and the adsorption 'footedness' of the system. Specifically, the creation of a truly homochiral surface must ensure that a single chirality is expressed for each aspect, and requires not only the control of molecule handedness but also direct control over footedness. Here, we demonstrate the ability to engineer homochiral footedness by a structural modification of enantiopure (S)-proline, which normally creates a (4 x 2) organization on a Cu(110) surface with heterochiral footedness. This modification of proline via the addition of a double bond within the pyrrolidine ring, yielding 3-pyrroline-2-carboxylic acid (PCA), is sufficient to drive the footprints of the entire (4 x 2) assembly from heterochiral to homochiral, leading to the creation of a truly homochiral interface The effects of modifications upon the footprint arrangements were characterized at the single-molecule level by scanning tunnelling microscopy, reflection absorption infrared spectroscopy and periodic density functional theory calculations. The control of adsorption footprints is not only pivotal to tailoring chirality at surfaces but also plays a key role in dictating the organization, the outward facing functionalities and the response of the organic-inorganic interface.
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18.
  • Karusala, N., et al. (författare)
  • The Future of Care Work : Towards a Radical Politics of Care in CSCW Research and Practice
  • 2021
  • Ingår i: Proceedings of the ACM Conference on Computer Supported Cooperative Work, CSCW 2021. - New York, NY, USA : Association for Computing Machinery (ACM). ; , s. 338-342
  • Konferensbidrag (refereegranskat)abstract
    • Computer-Supported Cooperative Work (CSCW) and Human- Computer Interaction (HCI) have long studied how technology can support material and relational aspects of care work, typically in clinical healthcare settings. More recently, we see increasing recognition of care work such as informal healthcare provision, child and elderly care, organizing and advocacy, domestic work, and service work. However, the COVID-19 pandemic has underscored long-present tensions between the deep necessity and simultaneous devaluation of our care infrastructures. This highlights the need to attend to the broader social, political, and economic systems that shape care work and the emerging technologies being used in care work. This leads us to ask several critical questions: What counts as care work and why? How is care work (de)valued, (un)supported, or coerced under capitalism and to what end? What narratives drive the push for technology in care work and whom does it benefit? How does care work resist or build resilience against and within oppressive systems? And how can we as researchers advocate for and with care and caregivers? In this one-day workshop, we will bring together researchers from academia, industry, and community-based organizations to reflect on these questions and extend conversations on the future of technology for care work.
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19.
  • Mahindra, Anuj, et al. (författare)
  • New Cancers after Autotransplantations for Multiple Myeloma
  • 2015
  • Ingår i: Biology of blood and marrow transplantation. - : Elsevier BV. - 1083-8791 .- 1523-6536. ; 21:4, s. 738-745
  • Tidskriftsartikel (refereegranskat)abstract
    • We describe baseline incidence and risk factors for new cancers in 4161 persons receiving autotransplants for multiple myeloma in the United States from 1990 to 2010. Observed incidence of invasive new cancers was compared with expected incidence relative to the US population. The cohort represented 13,387 person-years at-risk. In total, 163 new cancers were observed, for a crude incidence rate of 1.2 new cancers per 100 person-years and cumulative incidences of 2.6% (95% confidence interval [CI], 2.09 to 3.17), 4.2% (95% CI, 3.49 to 5.00), and 6.1% (95% CI, 5.08 to 7.24) at 3, 5, and 7 years, respectively. The incidence of new cancers in the autotransplantation cohort was similar to age-, race-, and gender-adjusted comparison subjects with an observed/expected (O/E) ratio of 1.00 (99% CI, .81 to 1.22). However, acute myeloid leukemia and melanoma were observed at higher than expected rates with O/E ratios of 5.19 (99% CI, 1.67 to 12.04; P = .0004), and 3.58 (99% CI, 1.82 to 6.29; P < .0001), respectively. Obesity, older age, and male gender were associated with increased risks of new cancers in multivariate analyses. This large data set provides a baseline for comparison and defines the histologic type specific risk for new cancers in patients with MM receiving postautotransplantation therapies, such as maintenance.
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20.
  • Raval, Aparna, et al. (författare)
  • Downregulation of death-associated protein kinase 1 (DAPK1) in chronic lymphocytic leukemia
  • 2007
  • Ingår i: Cell. - : Elsevier BV. - 0092-8674 .- 1097-4172. ; 129:5, s. 879-890
  • Tidskriftsartikel (refereegranskat)abstract
    • The heritability of B cell chronic lymphocytic leukemia (CLL) is relatively high; however, no predisposing mutation has been convincingly identified. We show that loss or reduced expression of death-associated protein kinase 1 (DAPK1) underlies cases of heritable predisposition to CLL and the majority of sporadic CLL. Epigenetic silencing of DAPK1 by promoter methylation occurs in almost all sporadic CLL cases. Furthermore, we defined a disease haplotype, which segregates with the CLL phenotype in a large family. DAPK1 expression of the CLL allele is downregulated by 75% in germline cells due to increased HOXB7 binding. In the blood cells from affected family members, promoter methylation results in additional loss of DAPK1 expression. Thus, reduced expression of DAPK1 can result from germline predisposition, as well as epigenetic or somatic events causing or contributing to the CLL phenotype.
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21.
  • Raval, NR, et al. (författare)
  • An in vivo Pig Model for Testing Novel Positron Emission Tomography Radioligands Targeting Cerebral Protein Aggregates
  • 2022
  • Ingår i: Frontiers in neuroscience. - : Frontiers Media SA. - 1662-4548 .- 1662-453X. ; 16, s. 847074-
  • Tidskriftsartikel (refereegranskat)abstract
    • Positron emission tomography (PET) has become an essential clinical tool for diagnosing neurodegenerative diseases with abnormal accumulation of proteins like amyloid-β or tau. Despite many attempts, it has not been possible to develop an appropriate radioligand for imaging aggregated α-synuclein in the brain for diagnosing, e.g., Parkinson’s Disease. Access to a large animal model with α-synuclein pathology would critically enable a more translationally appropriate evaluation of novel radioligands. We here establish a pig model with cerebral injections of α-synuclein preformed fibrils or brain homogenate from postmortem human brain tissue from individuals with Alzheimer’s disease (AD) or dementia with Lewy body (DLB) into the pig’s brain, using minimally invasive surgery and validated against saline injections. In the absence of a suitable α-synuclein radioligand, we validated the model with the unselective amyloid-β tracer [11C]PIB, which has a high affinity for β-sheet structures in aggregates. Gadolinium-enhanced MRI confirmed that the blood-brain barrier was intact. A few hours post-injection, pigs were PET scanned with [11C]PIB. Quantification was done with Logan invasive graphical analysis and simplified reference tissue model 2 using the occipital cortex as a reference region. After the scan, we retrieved the brains to confirm successful injection using autoradiography and immunohistochemistry. We found four times higher [11C]PIB uptake in AD-homogenate-injected regions and two times higher uptake in regions injected with α-synuclein-preformed-fibrils compared to saline. The [11C]PIB uptake was the same in non-injected (occipital cortex, cerebellum) and injected (DLB-homogenate, saline) regions. With its large brain and ability to undergo repeated PET scans as well as neurosurgical procedures, the pig provides a robust, cost-effective, and good translational model for assessment of novel radioligands including, but not limited to, proteinopathies.
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22.
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23.
  • Raval, NR, et al. (författare)
  • Synaptic Density and Neuronal Metabolic Function Measured by Positron Emission Tomography in the Unilateral 6-OHDA Rat Model of Parkinson's Disease
  • 2021
  • Ingår i: Frontiers in synaptic neuroscience. - : Frontiers Media SA. - 1663-3563. ; 13, s. 715811-
  • Tidskriftsartikel (refereegranskat)abstract
    • Parkinson’s disease (PD) is caused by progressive neurodegeneration and characterised by motor dysfunction. Neurodegeneration of dopaminergic neurons also causes aberrations within the cortico-striato-thalamo-cortical (CSTC) circuit, which has been hypothesised to lead to non-motor symptoms such as depression. Individuals with PD have both lower synaptic density and changes in neuronal metabolic function in the basal ganglia, as measured using [11C]UCB-J and [18F]FDG positron emission tomography (PET), respectively. However, the two radioligands have not been directly compared in the same PD subject or in neurodegeneration animal models. Here, we investigate [11C]UCB-J binding and [18F]FDG uptake in the CSTC circuit following a unilateral dopaminergic lesion in rats and compare it to sham lesioned rats. Rats received either a unilateral injection of 6-hydroxydopamine (6-OHDA) or saline in the medial forebrain bundle and rostral substantia nigra (n = 4/group). After 3 weeks, all rats underwent two PET scans using [18F]FDG, followed by [11C]UCB-J on a separate day. [18F]FDG uptake and [11C]UCB-J binding were both lower in the ipsilateral striatal regions compared to the contralateral regions. Using [11C]UCB-J, we could detect an 8.7% decrease in the ipsilateral ventral midbrain, compared to a 2.9% decrease in ventral midbrain using [18F]FDG. Differential changes between hemispheres for [11C]UCB-J and [18F]FDG outcomes were also evident in the CSTC circuit’s cortical regions, especially in the orbitofrontal cortex and medial prefrontal cortex where higher synaptic density yet lower neuronal metabolic function was observed, following lesioning. In conclusion, [11C]UCB-J and [18F]FDG PET can detect divergent changes following a dopaminergic lesion in rats, especially in cortical regions that are not directly affected by the neurotoxin. These results suggest that combined [11C]UCB-J and [18F]FDG scans could yield a better picture of the heterogeneous cerebral changes in neurodegenerative disorders.
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24.
  • Shalgunov, Vladimir, et al. (författare)
  • Blocking of efflux transporters in rats improves translational validation of brain radioligands
  • 2020
  • Ingår i: EJNMMI Research. - : SPRINGER. - 2191-219X. ; 10:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background Positron emission tomography (PET) is a molecular imaging technique that can be used to investigate the in vivo pharmacology of drugs. Initial preclinical evaluation of PET tracers is often conducted in rodents due to the accessibility of disease models as well as economic considerations. Compared to larger species, rodents display a higher expression and/or activity of efflux transporters such as the P-glycoprotein (P-gp). Low brain uptake could, therefore, be species-specific and uptake in rodents not be predictive for that in humans. We hypothesized that a better prediction from rodent data could be achieved when a tracer is evaluated under P-gp inhibition. Consequently, we compared the performance of eight neuroreceptor tracers in rats with and without P-gp inhibition including a specific binding blockade. This data set was then used to predict the binding of these eight tracers in pigs. Methods PET tracers targeting serotonin 5-HT(2A)receptors ([F-18]MH.MZ, [F-18]Altanserin, [C-11]Cimbi-36, [C-11]Pimavanserin), serotonin 5-HT(7)receptors ([C-11]Cimbi-701, [C-11]Cimbi-717 and [C-11]BA-10) and dopamine D(2/3)receptors ([F-18]Fallypride) were used in the study. The brain uptake and target-specific binding of these PET radiotracers were evaluated in rats with and without inhibition of P-gp. Rat data were subsequently compared to the results obtained in pigs. Results Without P-gp inhibition, the amount of target-specific binding in the rat brain was sufficient to justify further translation for three out of eight evaluated tracers. With P-gp inhibition, results for five out of eight tracers justified further translation. The performance in pigs could correctly be predicted for six out of eight tracers when rat data obtained under P-gp inhibition were used, compared to four out of eight tracers without P-gp inhibition. Conclusions P-gp strongly affects the uptake of PET tracers in rodents, but false prediction outcomes can be reduced by evaluating a tracer under P-gp inhibition.
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25.
  • Divaris, K, et al. (författare)
  • The academic environment: the students' perspective
  • 2008
  • Ingår i: European journal of dental education : official journal of the Association for Dental Education in Europe. - : Wiley. - 1396-5883. ; 1212 Suppl 1, s. 120-130
  • Tidskriftsartikel (refereegranskat)
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26.
  • Donovan, P., et al. (författare)
  • Unexpected Deformations Induced by Surface Interaction and Chiral Self-Assembly of Co-II-Tetraphenylporphyrin (Co-TPP) Adsorbed on Cu(110): A Combined STM and Periodic DFT Study
  • 2010
  • Ingår i: Chemistry - A European Journal. - : Wiley. - 1521-3765 .- 0947-6539. ; 16:38, s. 11641-11652
  • Tidskriftsartikel (refereegranskat)abstract
    • In a combined scanning tunnelling microscopy (STM) and periodic density functional theory (DFT) study, we present the first comprehensive picture of the energy costs and gains that drive the adsorption and chiral self-assembly of highly distorted Co-II-tetraphenylporphyrin (Co-TPP) conformers on the Cu(110) surface. Periodic, semi-local DFT calculations reveal a strong energetic preference for Co-TPP molecules to adsorb at the short-bridge site when organised within a domain. At this adsorption site, a substantial chemical interaction between the molecular core and the surface causes the porphyrin macrocycle to accommodate close to the surface and in a flat geometry, which induces considerable tilting distortions in the phenyl groups. Experimental STM images can be explained in terms of these conformational changes and adsorption-induced electronic effects. For the ordered structure we unambiguously show that the substantial energy gain from the molecule surface interaction recuperates the high cost of the induced molecular and surface deformations as compared with gas phase molecules. Conversely, singly adsorbed molecules prefer a long-bridge adsorption site and adopt a non-planar, saddle-shape conformation. By using a van der Waals density functional correction scheme, we found that the intermolecular pi-pi interactions make the distorted conformer more stable than the saddle conformer within the organic assembly. These interactions drive supramolecular assembly and also generate chiral expression in the system, pinning individual molecules in a propeller-like conformation and directing their assembly along non-symmetric directions that lead to the coexistence of mirror-image chiral domains. Our observations reveal that a strong macrocycle surface interaction can trigger and stabilise highly unexpected deformations of the molecular structure and thus substantially extend the range of chemistries possible within these systems.
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27.
  • Dyer, M. S., et al. (författare)
  • Understanding the Interaction of the Porphyrin Macrocycle to Reactive Metal Substrates: Structure, Bonding, and Adatom Capture
  • 2011
  • Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-086X .- 1936-0851. ; 5:3, s. 1831-1838
  • Tidskriftsartikel (refereegranskat)abstract
    • We investigate the absorption and conformation of free-base porphines on Cu(110) using STM, reflection absorption infrared spectroscopy, and periodic DFT calculations in order to understand how the central polypyrrole macrocycle, common to all porphyrins, interacts with a reactive metal surface. We find that,the-macrocycle forms a chemisorption bond with the surface,, arising from electron donation into down-shifted, and nearly degenerate unoccupied porphine orbitals accompanied with electron back-donation from molecular pi-orbitals. Our calculations show that van der Waals interactions give rise to an overall Increase in the adsorption energy but only minor changes in the adsorption geometry and electronic structure. In addition, we observe copper adatoms being weakly attracted to adsorbed porphines at specific molecular sites. These results provide important insights into porphyrin-surface interactions that ultimately, will govern the design of robust surface mounted molecular devices based on this important class of molecules.
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28.
  • Haq, S., et al. (författare)
  • Clean Coupling of Unfunctionalized Porphyrins at Surfaces To Give Highly Oriented Organometallic Oligomers
  • 2011
  • Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 133:31, s. 12031-12039
  • Tidskriftsartikel (refereegranskat)abstract
    • The direct coupling of complex, functional organic molecules at a surface is one of the outstanding challenges in the road map to future molecular devices. Equally demanding is to meet this challenge without recourse to additional functionalization of the molecular building blocks and via clean surface reactions that leave no surface contamination. Here, we demonstrate the directional coupling of unfunctionalized porphyrin molecules-large aromatic multifunctional building blocks-on a single crystal copper surface, which generates highly oriented one-dimensional organometallic macromolecular nanostructures (wires) in a reaction which generates gaseous hydrogen as the only byproduct. In situ scanning tunneling microscopy and temperature programmed desorption, supported by theoretical modeling, reveal that the process is driven by C-H bond scission and the incorporation of copper atoms in between the organic components to form a very stable organocopper oligomer comprising organometallic edge-to-edge porphyrin-Cu-porphyrin connections on the surface that are unprecedented in solution chemistry. The hydrogen generated during the reaction leaves the surface and, therefore, produces no surface contamination. A remarkable feature of the wires is their stability at high temperatures (up to 670 K) and their preference for 1D growth along a prescribed crystallographic direction of the surface. The on-surface formation of directional organometallic wires that link highly functional porphyrin cores via direct C-Cu-C bonds in a single-step synthesis is a new development in surface-based molecular systems and provides a versatile approach to create functional organic nanostructures at surfaces.
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  • Patra, B., et al. (författare)
  • A genome wide dosage suppressor network reveals genomic robustness
  • 2017
  • Ingår i: Nucleic Acids Research. - : Oxford University Press. - 0305-1048 .- 1362-4962. ; 45:1, s. 255-270
  • Tidskriftsartikel (refereegranskat)abstract
    • Genomic robustness is the extent to which an organism has evolved to withstand the effects of deleterious mutations. We explored the extent of genomic robustness in budding yeast by genome wide dosage suppressor analysis of 53 conditional lethal mutations in cell division cycle and RNA synthesis related genes, revealing 660 suppressor interactions of which 642 are novel. This collection has several distinctive features, including high cooccurrence of mutant-suppressor pairs within protein modules, highly correlated functions between the pairs and higher diversity of functions among the co-suppressors than previously observed. Dosage suppression of essential genes encoding RNA polymerase subunits and chromosome cohesion complex suggests a surprising degree of functional plasticity of macromolecular complexes, and the existence of numerous degenerate pathways for circumventing the effects of potentially lethal mutations. These results imply that organisms and cancer are likely able to exploit the genomic robustness properties, due the persistence of cryptic gene and pathway functions, to generate variation and adapt to selective pressures. © 2016 The Author(s).
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  • Temprano, I, et al. (författare)
  • 1D self-assembly of chemisorbed thymine on Cu(110) driven by dispersion forces.
  • 2015
  • Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 142:10
  • Tidskriftsartikel (refereegranskat)abstract
    • Adsorption of thymine on a defined Cu(110) surface was studied using reflection-absorption infrared spectroscopy (RAIRS), temperature programmed desorption (TPD), and scanning tunnelling microscopy (STM). In addition, density functional theory (DFT) calculations were undertaken in order to further understand the energetics of adsorption and self-assembly. The combination of RAIRS, TPD, and DFT results indicates that an upright, three-point-bonded adsorption configuration is adopted by the deprotonated thymine at room temperature. DFT calculations show that the upright configuration adopted by individual molecules arises as a direct result of strong O-Cu and N-Cu bonds between the molecule and the surface. STM data reveal that this upright thymine motif self-assembles into 1D chains, which are surprisingly oriented along the open-packed [001] direction of the metal surface and orthogonal to the alignment of the functional groups that are normally implicated in H-bonding interactions. DFT modelling of this system reveals that the molecular organisation is actually driven by dispersion interactions, which cause a slight tilt of the molecule and provide the major driving force for assembly into dimers and 1D chains. The relative orientations and distances of neighbouring molecules are amenable for π-π stacking, suggesting that this is an important contributor in the self-assembly process.
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