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On the sampling strategies and models for measuring diffusion exchange with a double diffusion encoding sequence

Magnetic Resonance Letters 2023年第3期3卷 232-247,I0003页

作者： Alfredo Ordinola Shan Cai Peter Lundberg Ruiliang Bai evren ozarslan Department of Biomedical Engineering(IMT) Link oping UniversityLink opingS-58185Sweden Department of Radiation Physics Department of HealthMedicine and Caring Sciences(HMV)Link oping UniversityLink opingS-58183Sweden Center for Medical Image Science and Visualization(CMIV) Link oping UniversityLink opingS-58185Sweden School of Medicine Zhejiang University866 Yuhangtang RdHangzhou310058China

Water exchange between the different compartments of a heterogeneous specimen can be characterized via diffusion magnetic resonance imaging(dMRI).Many analysis frameworks using dMRI data have been proposed to describe exchange,often using a double diffusion encoding(DDE)stimulated echo *** such as diffusion exchange weighted imaging(DEWI)and the filter exchange and rapid exchange models,use a specific subset of the full space DDE *** this work,a general representation of the DDE signal was employed with different sampling schemes(namely constant b1,diagonal and anti-diagonal)from the data reduction models to estimate exchange.A near-uniform sampling scheme was proposed and compared with the other sampling *** filter exchange and rapid exchange models were also applied to estimate exchange with their own subsampling *** subsampling schemes and models were compared on both simulated data and experimental data acquired with a benchtop MR *** synthetic data,the diagonal and near-uniform sampling schemes performed the best due to the consistency of their estimates with the ground *** experimental data,the shifted diagonal and near-uniform sampling schemes outperformed the others,yielding the most consistent estimates with the full space *** results suggest the feasibility of measuring exchange using a general representation of the DDE signal along with variable sampling *** future studies,algorithms could be further developed for the optimization of sampling schemes,as well as incorporating additional properties,such as geometry and diffusion anisotropy,into exchange frameworks.

关键词： Diffusion MRI Water exchange Sampling schemes Double diffusion encoding

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Diffusivity-limited q-space trajectory imaging

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Magnetic Resonance Letters 2023年第2期3卷 187-196,I0005页

作者： Deneb Boito Magnus Herberthson Tom Dela Haije Ida Blystad evren ozarslan Department of Biomedical Engineering Campus USLinkoping UniversityLinkopingSE-58183.Sweden Center for Medical Image Science and Visualization Linkoping UniversityLinkopingSE-58183Sweden Department of Mathematics Linkoping UniversityLinkopingSE-58183Sweden Department of Computer Science University of CopenhagenCopenhagenDK-2300Denmark Department of Radiology in Linkoping and Department of Health Medicine and Caring SciencesLinkoping UniversityLinkopingSE-58183Sweden

Q-space trajectory imaging(QTI)allows non-invasive estimation of microstructural features of heterogeneous porous media via diffusion magnetic resonance imaging performed with generalised gradient waveforms.A recently proposed constrained estimation framework,called QTI+,improved QTI's resilience to noise and data sparsity,thus increasing the reliability of the method by enforcing relevant positivity *** this work we consider expanding the set of constraints to be applied during the fitting of the QTI *** show that the additional conditions,which introduce an upper bound on the diffusivity values,further improve the retrieved parameters on a publicly available human brain dataset as well as on data acquired from healthy volunteers using a scanner-ready protocol.

关键词： Diffusion Diffusion MRI q-space trajectory imaging QTI Microstructure Microscopic anisotropy QTI+ Constrained

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ON THE m^(th) ORDER DIFFERENCE SEQUENCE SPACE OF GENERALIZED WEIGHTED MEAN AND COMPACT OPERATORS

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Acta Mathematica Scientia 2013年第3期33卷 797-813页

作者： Metin BASARIR Emrah evren KARA Department of Mathematics Sakarya University Department of Mathematics Bilecik Seyh Edebali University

In this article, using generalized weighted mean and difference matrix of order m, we introduce the paranormed sequence space l（u, v, p; △（m））, which consist of the sequences whose generalized weighted △（m）-difference means are in the linear space l（p） defined by ***. Also, we determine the basis of this space and compute its α-, β- and γ-duals. Further, we give the characterization of the classes of matrix mappings from l（u, v, p, △（m）） to l∞, c, and co. Finally, we apply the Hausdorff measure of noncompacness to characterize some classes of compact operators given by matrices on the space lp（U, v, △（m））（1 ≤ p 〈 ∞）.

关键词： Paranormed sequence spaces difference sequence spaces weighted mean α-,β, γ-duals, matrix mappings Hausdorff measure of noncompactness compactoperators

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Highly efficient three-phase grid-connected parallel inverter system

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Journal of Modern Power Systems and Clean Energy 2018年第5期6卷 1079-1089页

作者： evren ISEN Ahmet Faruk BAKAN Department of Electrical and Electronics Engineering Kirklareli University Department of Electrical Engineering Yildiz Technical University

In this paper, a new three-phase grid-connected inverter system is proposed. The proposed system includes two inverters. The main inverter, which operates at a low switching frequency, transfers active power to the grid. The auxiliary inverter processes a very low power to compensate for the grid current ripple. Thus, no active power is processed by the auxiliary inverter. The goal is to produce a grid current with a low total harmonic distortion(THD) and to obtain the highest efficiency from the inverter system. The main inverter is controlled via a space-vector pulse-width modulation owing to its optimum switching pattern, and the auxiliary inverter is controlled via a hysteresis current-control technique owing to the technique's fast dynamic response. The proposed system is analyzed in terms of different DC-link voltage, switching frequency,and filter inductance values. The optimum system parameters are selected that provide a THD value of less than 5%.A prototype inverter system at a 10 kW output power has been implemented. The main inverter operates at a 3 kHz switching frequency, and the auxiliary inverter compensates for the grid-current ripple. In total, a THD of 4.33%and an efficiency of 97.86% are obtained using the proposed inverter system prototype.

关键词： Active filter Inverter efficiency Ripple cancellation Three-phase grid-connected inverter

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Dynamical Model to Optimize Student’s Academic Performance

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Computer Modeling in Engineering & Sciences 2022年第8期132卷 393-411页

作者： evren Hincal Amna Hashim Alzadjali Department of Mathematics Near East UniversityMersin10 KKTCCyprus

Excellent student’s academic performance is the uppermost priority and goal of educators and *** dubious marginal rate between admission and graduation rates unveils the rates of dropout and withdrawal from *** improve the academic performance of students,we optimize the performance indices to the dynamics describing the academic performance in the form of nonlinear system *** established the uniform boundedness of the model and the existence and uniqueness *** independence and interdependence equilibria were found to be locally and globally asymptotically *** optimal control analysis was carried out,and lastly,numerical simulation was run to visualize the impact of the performance index in optimizing academic performance.

关键词： Academic performance optimal control uniform boundedness Pontryagin Maximum Principle(PMP) existence and uniqueness stability

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Reducing the Range of Cancer Risk on BI-RADS 4 Subcategories via Mathematical Modelling

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Computer Modeling in Engineering & Sciences 2022年第10期133卷 93-109页

作者： Nezihal Gokbulut evren Hincal Hasan Besim Bilgen Kaymakamzade Near East University Faculty of Arts and SciencesNicosia99138North Cyprus Near East University Mathematics Research CenterNicosia99138North Cyprus Near East University Faculty of MedicineNicosia99138North Cyprus

Breast Imaging Reporting and Data System,also known as BI-RADS is a universal system used by radiologists and *** constructs a comprehensive language for the diagnosis of breast ***-RADS 4 category has a wide range of cancer risk since it is divided into 3 *** play an important role in the diagnosis and treatment of *** this study,data of 42 BI-RADS 4 patients taken fromthe Center for Breast Health,Near East University Hospital is *** the analysis,a mathematical model is constructed by dividing the population into 4 *** analysis is applied to the parameters with the desired outcome of a reduced range of cancer *** simulations of the parameters are *** results of the model have revealed that an increase in the lactation rate and earlymenopause have a negative correlation with the chance of being diagnosed with BI-RADS 4 whereas a positive correlation increase in age,the palpable mass,and family history is ***,the negative effects of smoking and late menopause on BI-RADS 4C diagnosis are vehemently ***,the model showed that the percentages of parameters play an important role in the diagnosis of BI-RADS 4 *** things considered,with the assistance of the most effective parameters,the range of cancer risks in BI-RADS 4 subcategories will decrease.

关键词： Mathematical model breast cancer BI-RADS 4 sensitivity analysis reducing cancer risk suspicious malignancy ordinary differential equations

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Performance of fluoride and boron compounds against drywood and subterranean termites and decay and mold fungi

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Journal of Forestry Research 2020年第4期31卷 1425-1434页

作者： S.Nami Kartal evren Terzi Tsuyoshi Yoshimura Faculty of Forestry Istanbul University-Cerrahpas¸a34473 BahcekoyIstanbulTurkey RISH Kyoto UniversityUjiKyoto 611-1100Japan

Sodium fluoride(NaF)and disodium octaborate tetrahydrate(DOT)are well-known fungicides for preventing and remediating decay in wood and wood structures,due to their excellent diffusion properties in *** efficacy of both compounds against drywood termites is,however,inadequately studied;there is a lack of information on the development of proper protection and control methods against drywood termites using these diffusible *** this study,the threshold values of fluoride and boron against drywood and subterranean termites and decay and mold fungi were assessed in laboratory *** Cryptomeria japonica ***(sugi)sapwood specimens with four different concentrations of NaF and DOT applied by either dipping or vacuum processes were subjected to attack by drywood termites,Incisitermes minor(Hagen)for 6 *** specimens were also tested against subterranean termites,Coptotermes formosanus Shiraki for 3 *** decay and mold resistance tests were then performed to determine the efficacy of the compounds against fungal *** showed 80%or greater drywood termite mortality in wood specimens treated with NaF at a retention level of1.7 kg m-3 or *** DOT treated groups,higher retention levels(greater than 6.8 kg m-3)were needed to reach up to 80%or more termite *** general,weight losses in NaF-treated specimens were slightly lower than those in DOT-treated *** levels of around1.2 kg m-3 for NaF and 1.6 kg m-3 for DOT were high enough to reach the JIS K 1571 threshold requirement of weight loss less than 3%in subterranean termite resistance *** higher termite mortality values were seen in the DOT than NaF treatments at respective retention *** decay resistance tests,no weight losses were seen at a NaF retention level of 2.3 kg m-3;however,a retention level of nearly 4 kg m-3 for DOT was needed for complete protection against both test *** most cases,lower weight losses were obtained i

关键词： NaF DOT Remedial treatments Termites Fungi

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Surface Pencil with a Common Line of Curvature in Minkowski 3-Space

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Acta Mathematica Sinica,English Series 2014年第12期30卷 2103-2118页

作者： evren ERGN Ergin BAYRAM Emin KASAP Ondokuz Mayis University arsamba Chamber of Commerce Vocational School Ondokuz Mayis University Faculty of Arts and SciencesMathematics Department

In this paper, we analyze the problem of constructing a surface pencil from a given spacelie （timelike） line of curvature. Using the Frenet frame of the given line of curvature in Minkowski 3-space, we express the surface pencil as a linear combination of this frame and derive the necessary and sufficient conditions for the coefficients to satisfy the line of curvature requirement. We illustrate this method by presenting some examples.

关键词： Minkowski space line of curvature surface pencil

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Sensitivity Analysis of COVID-19 in Mediterranean Island

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Computer Modeling in Engineering & Sciences 2022年第1期130卷 133-148页

作者： Ahmet Savasan Bilgen Kaymakamzade Nezihal Gokbulut evren Hincal Elcin Yoldascan Near East University Faculty of Arts and SciencesNicosia99138North Cyprus Near East University Mathematics Research CenterNicosia99138North Cyprus Cyprus International University Faculty of MedicineNicosia99138North Cyprus

The aim of this study is to examine the progress of the worldwide pandemic *** authors,we have decided to analyze the situation of COVID-19 onMediterranean islandwith accurate *** this purpose,amathematical model is constructed and proposed by dividing the whole population into sensible and suitable *** study captures the dates February 01 till May 15,*** the control of the spread of disease,vaccination and infection rates are compared and *** calculations and comparison,MatLab software is *** of the data that are used are taken from the Ministry of *** effect of parameters is examined with sensitivity ***,with this analysis,values of parameters are ***,by using the constructed model,the effect of vaccine on infected individuals is analyzed *** a result,it is concluded that the studied part of the island is late for the control of the disease via *** can be explained by two main reasons;vaccinating the people that are not inmobilitymost of the time(aged people and people with chronic diseases)and getting the vaccine ***,the results showed that this rate and distribution of vaccines would not be enough to control the pandemic on the island.

关键词： COVID-19 vaccination mathematical model basic reproduction number island sensitivity analysis

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Current update on nanoplatforms as therapeutic and diagnostic tools:A review for the materials used as nanotheranostics and imaging modalities

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Asian Journal of Pharmaceutical Sciences 2021年第1期16卷 24-46页

作者： Panoraia I.Siafaka Neslihan Ustundag Okur Ioannis D.Karantas Mehmet evren Okur evren Atlihan Gundogdu Department of Chemistry Aristotle University of ThessalonikiThessalonikiGreece Faculty of Pharmacy Department of Pharmaceutical TechnologyUniversity of Health SciencesIstanbulTurkey 2nd Clinic of Internal Medicine Hippokration General HospitalThessalonikiGreece Faculty of Pharmacy Department of PharmacologyUniversity of Health SciencesIstanbulTurkey Faculty of Pharmacy Department of RadiopharmacyEge UniversityIzmir 35100Turkey

In the last decade,the use of nanotheranostics as emerging diagnostic and therapeutic tools for various diseases,especially cancer,is held great *** to date,several approaches have been employed in order to develop smart nanotheranostics,which combine bioactive targeting on specific tissues as well as diagnostic *** nanotheranostics can deliver therapeutic agents by concomitantly monitor the therapy response in ***,the possibility of over-or under-dosing is *** non-invasive imaging techniques have been used to quantitatively monitor the drug delivery *** of nanomaterials is widely used as powerful diagnostic approach on nuclear medicine *** fact,various radiolabeled nanomaterials have been designed and developed for imaging tumors and other lesions due to their efficient *** nanoparticles as gold,silver,silica based nanomaterials or organic nanoparticles as polymers,carbon based nanomaterials,liposomes have been reported asmultifunctional *** this review,the imaging modalities according to their use in various diseases are summarized,providing special details for *** further,the most current nanotheranostics categorized via the used nanomaterials are also summed *** conclude,this review can be beneficial for medical and pharmaceutical society as well as material scientists who work in the field of nanotheranostics since they can use this research as guide for producing newer and more efficient nanotheranostics.

关键词： Theranostics Nanomedicine Nanotechnology Nanoparticles Radiopharmaceuticals

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