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Effect of reaction and post-treatment conditions on physico-chemical properties of magnetic iron oxide nano-particles Author links open overlay panel

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Particuology 2024年第8期91卷 155-167页

作者： Masome Moeni Mohamed Edokali Matthew Rogers Oscar Cespedes Louey Tliba Tamseela Habib Robert Menzel Ali Hassanpour School of Chemical and Process Engineering Faculty of Engineering and Physical ScienceUniversity of LeedsLeedsLS29JTUK School of Physics and Astronomy Faculty of Engineering and Physical ScienceUniversity of LeedsLeedsLS29JTUK Mechanical Engineering Department University of Engineering&TechnologyLahorePakistan School of Chemistry Faculty of Engineering and Physical ScienceUniversity of LeedsLeedsLS29JTUK

Poor stability and dispersibility,as well as aggregation are considered as major challenges in clinical application of iron oxide nanoparticles(IONPs).Several studies have shown that the synthesis parameters and post-synthesis treatments e.g.,drying methods,have the capability to improve the particles'***,we investigate the combined effect of synthesis and post-treatment parameters on the particle size,stability and magnetism of ***(Fe_(3)O_(4))NPs were prepared via co-precipitation and post-treated using different methods,i.e.(i)freeze dried at-53℃,0.133 mbar for 48 h(liquid nitrogen frozen(LFD)and freezer frozen(FFD)),(ii)vacuum oven dried(VOD)at 60℃for 24 h,and(iii)kept wet colloidal(WET),dispersed in deionized *** Fe_(3)O_(4)NPs’chemical functional groups,size,shape,crystallinity,stability,aggregation,porosity,and magnetic properties were further analysed using different characterisation *** results showed that,while the WET sample had the best stability and significantly less aggregation at different temperatures,amongst post-treated Fe_(3)O_(4)NPs,LFD sample exhibited the best stability(up to 37℃),dispersion and smallest polydispersity ***,all dried NPs had superparamagnetic characteristics,while,LFD Fe_(3)O_(4)NPs had better magnetic properties and stability than other drying methods.

关键词： Iron oxide nanoparticles Co-precipitation Stability Aggregation Magnetic properties

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Effect of solid particle loading on nucleophilic addition of epoxy-resin to isophorone diisocyanate

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Particuology 2008年第1期6卷 24-29页

作者： Wei Zhang Richard S. Blackburn Abbas A. Dehghani-Sanij Green Chemistry Group Centre for Technical Textiles University of Leeds Leeds LS2 9JT UK School of Mechanical Engineering University of Leeds Leeds LS2 9JT UK

In the preparation of surface coatings made of conductive composites consisting of conductive particulate fillers in a soft matrix, cracks will develop with increase of the particulate loading, which is believed to be related to the nucleophilic addition reaction between glycidyl end-capped poly （bisphenol A-co-epichlorohydrin） and isophorone diisocyanate molecules. This curing reaction is responsible for the generation of crosslinking network throughout the coatings. The influence of solid particle loading on the chemical reaction may be described as a volume-excluded effect, that is, the high solid particle loading will occupy the space between the functional groups thus preventing the chemical reaction to take place. As a direct consequence, the cross-linking network cannot develop properly due to the insufficiency of curing reaction. This will lead to the generation of cracks, as was supported by FT-IR analysis in this work.

关键词： Particle loading Cracks Nucleophilic Addition FT-IR

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The N-formyl peptide receptors: contemporary roles in neuronal function and dysfunction

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Neural Regeneration Research 2020年第7期15卷 1191-1198页

作者： Peter J.G. Cussell Margarita Gomez Escalada Nathaniel G.N. Milton Andrew W.J. Paterson Centre for Biomedical Science Research School of Clinical and Applied Sciences Leeds Beckett University

N-formyl peptide receptors(FPRs)were first identified upon phagocytic leukocytes,but more than four decades of research has unearthed a plethora of non-myeloid roles for this receptor *** are expressed within neuronal tissues and markedly in the central nervous system,where FPR interactions with endogenous ligands have been implicated in the pathophysiology of several neurodegenerative diseases including Alzheimer's disease and Parkinson's disease,as well as neurological cancers such as *** the homeostatic function of FPRs in the nervous system is currently undefined,a variety of novel physiological roles for this receptor family in the neuronal context have been posited in both human and animal *** developments in recent years have implicated FPRs in the process of neurogenesis and neuronal differentiation which,upon greater characterisation,could represent a novel pharmacological target for neuronal regeneration therapies that may be used in the treatment of brain/spinal cord injury,stroke and *** review aims to summarize the recent progress made to determine the physiological role of FPRs in a neuronal setting,and to put forward a case for FPRs as a novel pharmacological target for conditions of the nervous system,and for their potential to open the door to novel neuronal regeneration therapies.

关键词： Alzheimer's disease formyl peptide receptor neural regeneration neuroblastoma neurodegeneration neuroinflammation neuronal differentiation stroke

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IR study on hydrogen bonding in epoxy resin–silica nanocomposites

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Progress in Natural Science:Materials International 2008年第7期18卷 801-805页

作者： Abbas A. Dehghani-Sanij Richard S. Blackburn School of Mechanical Engineering University of LeedsLeeds LS2 9JT UK Green Chemistry Group Centre for Technical Textiles University of LeedsLeeds LS2 9JT UK

The chemical and physical interactions between ingredients in composites play an important role in the improvement of service prop- erties. The nucleophilic addition between polymer and isophoron diisocyanate molecules was monitored by FT-IR technique. The inten- sity loss of isocyanate absorption band in conjunction with the intensity growth of carboxyl absorption band indicates the progress of reaction. FT-IR spectroscopy was also adopted to examine the intermolecular hydrogen bonding of epoxy resin with silica as well as intramolecular one within polymer matrix. The vibration frequency of carboxyl group (-C=O) and hydroxyl group (-OH) shifts from 1736 to 1728 cm-1and 3420 to 3414 cm-1, respectively, indicating the occurrence of hydrogen bonding between -C=O and -OH. The vibration frequency of Si-OH moves from 3435 to 3414 cm-1, suggesting the involvement of silica. Whereas the vibration frequency of pending -OH in polymer chain moves from 3435 to 3420 cm-1 or 3414 cm-1, proposing that this kind of interaction can also happen within polymer matrix.

关键词： Hydrogen bonding FT-IR Epoxy resin Silica

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Computationally efficient MUSIC based DOA estimation algorithm for FMCW radar

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Journal of Electronic Science and Technology 2023年第1期21卷 46-64页

作者： Bakhtiar Ali Karim Haitham Kareem Ali Department of Communication Engineering Sulaimani Polytechnic UniversitySulaymaniyah70-236Iraq

This paper proposes low-cost yet high-accuracy direction of arrival(DOA)estimation for the automotive frequency-modulated continuous-wave(FMcW)*** existing subspace-based DOA estimation algorithms suffer fromeither high computational costs or low *** aim to solve such contradictory relation between complexity and accuracy by using randomizedmatrix ***,we apply an easily-interpretablerandomized low-rank approximation to the covariance matrix(CM)and R∈C^(M×M)throughthresketch maties in the fom of R≈OBQ^(H).Here the approximately compute its *** is,we first approximate matrix Q∈C^(M×z)contains the orthonormal basis for the range of the sketchmatrik C∈C^(M×z)cwe whichis etrated fom R using randomized unifom counsampling and B∈C^(z×z)is a weight-matrix reducing the approximation *** on such approximation,we are able to accelerate the subspacecomputation by the orders of the magnitude without compromising estimation ***,we drive a theoretical error bound for the suggested scheme to ensure the accuracy of the *** validated by the simulation results,the DOA estimation accuracy of the proposed algorithm,eficient multiple signal classification(E-MUSIC)s high,closely tracks standardMUSIC,and outperforms the well-known algorithms with tremendouslyreduced time ***,the devised method can realize high-resolutionreal-time target detection in the emerging multiple input and multiple output(MIMO)automotive radar systems.

关键词： Computational complexity Direction of arrival(DOA)estimation Frequency-modulated continuous-wave(FMCW)radar Subspace algorithms

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Accuracy between clinical and radiological diagnoses compared to surgical orbital biopsies

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International Journal of Ophthalmology(English edition) 2023年第4期16卷 616-622页

作者： Audrey Tang Helen Hoi-Lam Ng Taras Gout Bernard Chang Nabil El-Hindy George Kalantzis School of Medicine Faculty of Medicine and HealthUniversity of LeedsLeedsLS2.9 JTUnited Kingdom Department of Ophthalmology St.James’s University HospitalLeeds Teaching Hospitals NHS TrustBeckett StreetLeedsLS97TFUnited Kingdom

AIM:To assess the concordance between diagnosing orbital lesions by clinical examination,orbital imaging,and histological evaluation,in order to help guide future research and clinical ***:A retrospective analysis was undertaken at a large regional tertiary referral centre of all surgical orbital biopsies performed over a 5-year period,from 1st January 2015 until 31st December *** and concordance between clinical,radiological and histological diagnoses are reported as percentage sensitivity and positive predictive ***:A total of 128 operations involving 111 patients were ***,sensitivities of 47.7%for clinical and 37.3%for radiological diagnoses were found when compared to the histological gold *** lesions that have characteristic clinical and radiological features had the highest sensitivity at 71.4%and 57.1%,*** conditions showed the lowest sensitivity in both clinical(30.3%)and radiological(18.2%)*** PPV for inflammatory conditions were 47.6%for clinical and 30.0%for radiological ***:Accurate diagnoses are difficult to reach by relying on clinical examination and imaging *** orbital biopsy with histological diagnosis should remain the gold standard approach for definitively identifying orbital *** larger scale prospective studies would help further refine concordance and guide future research avenues.

关键词： orbital biopsy orbital lesion histological diagnosis radiological diagnosis clinical diagnosis

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Last glacial geomorphologic records in Mt Chelmos, North Peloponnesus, Greece

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Journal of Mountain Science 2018年第5期15卷 948-965页

作者： Kosmas PAVLOPOULOS Aris LEONTARITIS Constantin D. ATHANASSAS Chara PETRAKOU Dimitris VANDARAKIS Kosnstantinos NIKOLAKOPOILOS Leonidas STAMATOPOULOS Katherina THEODORAKOPOULOU Paris Sorbonne university Abu Dhabi P.O. 38044 Abu Dhabi United Arab Emirates Harokopio university 70 El. Venizelou sir. 17671 Athens Greece Department of Geological Sciences School of Mining and Metallurgical Engineering National Technical University of Athens (NTUA) Zografos Athens 15780 Greece Hellenic Centre for Marine Research 46.7 Ion Athens-Sounio av. P.O. Box 712 Greece university of Patrus Geology Department University Campus 26504 Rio Achaia Greece National and Kapodistrian university of Athens Panepistimioupolis 15784 Ilissia Athens Greece

This study deals with the analysis of the glacial processes that have affected the relief of Mt Chelmos in northern Peloponnesus, Greece during middle and Late Pleistocene. The goal was to compile a combined geomorphological-geological map of the study area which would enable the chronological stratification of the glacial landforms cropping up on Mt. Chelmos. Chronological stratification was further aided by optically stimulated luminescence(OSL)dating. The map served as the basis upon which the reconstruction and discussion on the phases of the Middle-Late Quaternary paleoclimatic history of *** have been made. A sophisticated semiautomated method was first used to analyze the Digital Elevation Model(DEM), combined with Aster,Quickbird and ALOS imagery in order to identify glacial and periglacial, as well as karstic ***, these features along with other nonrecognizable features from the remote-sensing images were documented in the field. In this way, several glacial landforms were identified, such as moraines and cirques, indicating extended glaciation phases during the middle and Late Pleistocene. Additionally,a ground moraine located at an altitude of 1900-2050 m, within the Spanolakos glacial valley, was dated using the OSL-dating method. The resulting ages indicate a phase of glacier advance/stabilization during MIS-5 b(89-86 ka), which is in consistence with pollenrecord evidence from Greece and the *** above the floors of the highest cirques on Mount Tymphi(Hughes 2004). These glacial landforms postdate the youngest moraines on Mount Tymphi(Tymphian Stage MIS 5 d-2), and it has been argued that they might be Younger Dryas in age(Woodward and Hughes 2011) although this has not been confirmed by radiometric dating(Hughes et al. 2006 d).Recent field observations throughout the mountains of central Greece(Leontartitis and Pavlopoulos, unpublished data) demonstrate that the glaciation extent has been underestimated in several

关键词： Semi-automated geomorphologicalmapping Glacial geomorphology Mediterranean OSL dating

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An investigation on dissolution kinetics of single sodium carbonate particle with image analysis method

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Chinese Journal of Chemical Engineering 2016年第10期24卷 1487-1496页

作者： Changdong Li Carlos Amador Yulong Ding Institute of Particle Science and Engineering University of LeedsLeedsUK Procter&Gamble Newcastle-Upon-Tyne Innovation Centre NewcastleUK School of Chemical Engineering University of BirminghamBirminghamUK

Dissolution kinetics of sodium carbonate is investigated with the image analysis method at the approach of single *** dissolution experiments are carried out in an aqueous solution under a series of controlled temperature and p *** selected sodium carbonate particles are all spherical with the same mass and *** dissolution process is quantified with the measurement of particle diameter from dissolution *** concentration of dissolved sodium carbonate in solvent is calculated with the measured diameter of *** surface reaction model and mass transport model are implemented to determine the dissolution mechanism and quantify the dissolution rate constant at each experimental *** to the fitting results with both two models,it is clarified that the dissolution process at the increasing temperature is controlled by the mass transport of dissolved sodium carbonate travelling from particle surface into *** dissolution process at the increasing pH is controlled by the chemical reaction on particle ***,the dissolution rate constant for each single spherical sodium carbonate particle is quantified and the results show that the dissolution rate constant of single spherical sodium carbonate increases significantly with the rising of temperature,but decreases with the increasing of pH conversely.

关键词： Sodium carbonate Single particle Dissolution rate constant Image analysis

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Implementing physically active learning:Future directions for research,policy,and practice

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Journal of Sport and Health Science 2020年第1期9卷 41-49,F0003页

作者： Andy Daly-Smith Thomas Quarmby Victoria S.J.Archbold Ash C.Routen Jade L.Morris Catherine Gammon John B.Bartholomew Geir Kare Resaland Bryn Llewellyn Richard Allman Henry Dorling School of Sport Leeds Beckett UniversityLeedsLS63QSUK School of Sport Exercise and Health SciencesLoughborough UniversityE152GZUK School of Health Promotion and Human Performance Eastern Michigan UniversityYpsilantiMI 48197USA Centre for Diet and Activity Research MRC Epidemiology UnitUniversity of CambridgeCambridgeCB21TNUK Department of Kinesiology and Health Education The University of Texas at AustinAustinTX 78705USA Center for Physically Active Learning Faculty of EducationArts and SportsWestern Norway University of Applied SciencesSogndal5020 BergenNorway Tagtiv8 Ltd and Move&Learn LeedsWF27BSUK School of Sport Health and Social ScienceSolent UniversitySouthamptonSO 14 ORTUK

Purpose:To identify co-produced multi-stakeholder perspectives important for successful widespread physically active learning(PAL) adoption and ***:A total of 35 stakeholders(policymakers n=9;commercial education sector,n=8;teachers,n=3;researchers,n=15) attended a design thinking PAL *** formed 5 multi-disciplinary groups with at least 1 representative from each stakeholder *** group,facilitated by a researcher,undertook 2 tasks:(1) using Post-it Notes,the following question was answered:within the school day,what are the opportunities for learning combined with movement?and(2) structured as a washing-line task,the following question was answered:how can we establish PAL as the norm?All discussions were audio-recorded and *** analyses were conducted by 4 *** the analyses were complete,the main themes and subthemes were assigned to 4 predetermined categories:(1) PAL design and implementation,(2) priorities for practice,(3) priorities for policy,and(4) priorities for ***:The following were the main themes for PAL implementation:opportunities for PAL within the school day,delivery environments,learning approaches,and the intensity of *** main themes for the priorities for practice included teacher confidence and competence,resources to support delivery,and community of *** main themes for the policy for priorities included self-governance,the Office for Standards in Education,Children’s Services,and Skill,policy investment in initial teacher training,and curriculum *** main themes for the research priorities included establishing a strong evidence base,school-based PAL implementation,and a whole-systems ***:The present study is the first to identify PAL implementation factors using a combined multi-stakeholder *** achieve wider PAL adoption and implementation,future interventions should be evidence based and address implementation factors

关键词： Children Physical activity Physically active learning Policy School

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Using Raman shift and FT-IR spectra as quality indices of oil bit PDC cutters

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Petroleum 2019年第3期5卷 329-334页

作者： Rafid KAbbas Kanaan Mohammad Musa Chemical Engineering Dept. Faculty of EngineeringUniversity of Al-QadisiyahAl-Diwaniya City58002Iraq

Nowadays many of oil and gas wells are drilled extensively by Polycrystalline Diamond Compact(PDC)drill *** companies are manufacturing PDC cutters according to their *** of these companies concentrate their products of PDC cutters to be well resisting for abrasive *** wear of PDC inserts leads to money loss as well as delays the drilling procedures causing unexpected ***,it is crucially significant to evaluate the quality of the PDC cutters based on their resistance against abrasive *** present work concentrates on assessing the PDC cutters from various sources using two non-destructive analytical approaches:Raman-Shift and Fourier Transformation Infrared Ray(FT-IR)*** analysis of the PDC samples with the analytical techniques were validated with the previous experimental results obtained from micro and nano-scratch tests achieved on the same *** presented work could be performed on many PDC cutters from various manufacturers as the applied tests considered non-destructive compared to the traditional destructive techniques which leads the way for evaluating lots of PDC cutters without causing any *** analysis of the applied analytical approaches agreed with the results obtained from previous experimental scratch tests.

关键词： Raman-shift FT-IR Polycrystalline diamond compact(PDC) Drill bit wear

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