ORCID Profile
0000-0002-0027-8059
Current Organisations
Leiden University Medical Center
,
Key Laboratory of Cardiovascular Imaging and Research of Liaoning Province
,
General Hospital of northern theater command
,
Trinity College Dublin
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Publications
A Microscopic and Spectroscopic Study of Interactions between Carbon Nanotubes and a Conjugated Polymer
Publisher: American Chemical Society (ACS)
Date: 08-02-2002
DOI: 10.1021/JP013745F
Solubility and purity of nanotubes in arc discharge carbon powder
Publisher: Elsevier BV
Date: 03-2001
Reinforcement of macroscopic carbon nanotube structures by polymer intercalation: The role of polymer molecular weight and chain conformation
Publisher: American Physical Society (APS)
Date: 21-12-2005
Assessing left atrial function in patients with atrial fibrillation and valvular heart disease using cardiovascular magnetic resonance imaging
Publisher: Wiley
Date: 15-03-2022
DOI: 10.1002/CLC.23811
Abstract: Atrial fibrillation (AF) is common arrhythmia in valvular heart disease (VHD) and is associated with adverse outcomes. To evaluate the left atrial (LA) function in patients with AF‐VHD by cardiovascular magnetic resonance imaging feature tracking (CMR‐FT) using LA strain ( ε s / ε e / ε a ) and their corresponding strain rate (SRs/SRe/SRa). This was a retrospective cross‐sectional inter‐reader and intra‐reader reproducibility conducted from July 1, 2020, to January 31, 2021. A total of 39 patients with AF‐VHD (rheumatic heart valvular disease [RHVD] [ n = 22], degenerative heart valvular disease [DHVD] [ n = 17]) underwent MRI scans performed with drug‐controlled heart rate before correcting the rhythm and valves through maze procedure. Fifteen participants with normal cardiac MRI were included as healthy control. ε s /SRs, ε e /SRe, and ε a /SRa, corresponding to LA reservoir, conduit, and booster‐pump function, were assessed using Feature Tracking software (CVI42 v5.12.1). Compared with healthy controls, LA global strain parameters ( ε s / ε e / ε a /SRs/SRe/SRa) were significantly decreased (all p 0.001), while LA size and volume were increased in AF‐VHD group (all p 0.001). In the subgroup, RHVD group showed lower LA total ejection fraction (LATEF) and strain data than DHVD group (12.6% ± 3.3% vs. 19.4 ± 8.6, p = 0.001). Decreased LATEF was significantly related to altered LA strain and strain rate, especially in ε s , ε e , and SRs (Pearson/Spearman r/ρ = 0.856/0.837/0.562, respectively all p 0.001). Interstudy and intrastudy reproducibility were consistent for LA volumetry and strain parameters (intraclass correlation coefficient: 0.88–0.99). CMR‐FT can be used to assess the LA strain parameters, and identify LA dysfunction and deformation noninvasively, which could be a helpful functional imaging biomarker in the clinical treatment of AF‐VHD.
Third-order nonlinear optical response and nonlinear photoluminescence in multiwalled carbon nanotubes
Publisher: SPIE
Date: 17-03-2003
DOI: 10.1117/12.463642
Sex Differences in Phenotypes of Bicuspid Aortic Valve and Aortopathy
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-2017
DOI: 10.1161/CIRCIMAGING.116.005155
Abstract: This large multicenter, international bicuspid aortic valve (BAV) registry aimed to define the sex differences in prevalence, valve morphology, dysfunction (aortic stenosis/regurgitation), aortopathy, and complications (endocarditis and aortic dissection). Demographic, clinical, and echocardiographic data at first presentation of 1992 patients with BAV (71.5% men) were retrospectively analyzed. BAV morphology and valve function were assessed aortopathy configuration was defined as isolated dilatation of the sinus of Valsalva or sinotubular junction, isolated dilatation of the ascending aorta distal to the sinotubular junction, or diffuse dilatation of the aortic root and ascending aorta. New cases of endocarditis and aortic dissection were recorded. There were no significant sex differences regarding BAV morphology and frequency of normal valve function. When presenting with moderate/severe aortic valve dysfunction, men had more frequent aortic regurgitation than women (33.8% versus 22.2%, P .001), whereas women were more likely to have aortic stenosis (34.5% versus 44.1%, P .001). Men had more frequently isolated dilatation of the sinus of Valsalva or sinotubular junction (14.2% versus 6.7%, P .001) and diffuse dilatation of the aortic root and ascending aorta (16.2% versus 7.3%, P .001) than women. Endocarditis (4.5% versus 2.5%, P =0.037) and aortic dissections (0.5% versus 0%, P .001) occurred more frequently in men. Although there is a male predominance among patients with BAV, men with BAV had more frequently moderate/severe aortic regurgitation at first presentation compared with women, whereas women presented more often with moderate/severe aortic stenosis compared with men. Furthermore, men had more frequent aortopathy than women.
Defining Subclinical Myocardial Dysfunction and Implications for Patients With Diabetes Mellitus and Preserved Ejection Fraction
Publisher: Elsevier BV
Date: 09-2019
DOI: 10.1016/J.AMJCARD.2019.06.011
Abstract: Left ventricular (LV) global longitudinal strain (GLS) can detect subclinical myocardial systolic dysfunction in in iduals with diabetes. The present study investigates the clinical usefulness and incremental net benefit of identifying subclinical myocardial systolic dysfunction in in iduals with diabetes. A cohort of 397 type 2 diabetic in iduals was followed up for the occurrence of all-cause mortality. Clinical and echocardiographic data of diabetic patients were assessed retrospectively. LV GLS was evaluated on transthoracic echocardiography using speckle tracking imaging. Subclinical LV systolic dysfunction was defined as LV GLS > -17.0% from 104 healthy volunteers recruited from the community. A total of 178 (44.8%) diabetic in iduals had evidence of subclinical LV systolic dysfunction and 46 (11.6%) died during follow-up. The presence of subclinical LV systolic dysfunction was independently associated with all-cause mortality on follow-up (hazard ratio [HR] 2.83, 95% confidence interval [CI] 1.40 to 5.71, p = 0.004). Diabetic in iduals without subclinical LV systolic dysfunction had similar survival as the general population (standardized mortality ratio 0.94, 95% CI 0.52 to 1.58). Decision curve analysis showed identification of subclinical LV systolic dysfunction and quantification of LV GLS provided an incremental net clinical benefit at risk stratifying patients for risk of death at 5 years. In conclusion, subclinical LV systolic dysfunction is independently associated with all-cause mortality in diabetic patients. Decision curve analyses suggest use of LV GLS and identification of subclinical LV systolic dysfunction is clinically useful, and provided incremental net clinical benefit for diabetic in iduals.
Helium ion microscopy of graphene: beam damage, image quality and edge contrast
Publisher: IOP Publishing
Date: 24-07-2013
DOI: 10.1088/0957-4484/24/33/335702
Abstract: A study to analyse beam damage, image quality and edge contrast in the helium ion microscope (HIM) has been undertaken. The s le investigated was graphene. Raman spectroscopy was used to quantify the disorder that can be introduced into the graphene as a function of helium ion dose. The effects of the dose on both freestanding and supported graphene were compared. These doses were then correlated directly to image quality by imaging graphene flakes at high magnification. It was found that a high magnification image with a good signal to noise ratio will introduce very significant s le damage. A safe imaging dose of the order of 10(13) He(+) cm(-2) was established, with both graphene s les becoming highly defective at doses over 5 × 10(14) He(+) cm(-2).The edge contrast of a freestanding graphene flake imaged in the HIM was then compared with the contrast of the same flake observed in a scanning electron microscope and a transmission electron microscope. Very strong edge sensitivity was observed in the HIM. This enhanced edge sensitivity over the other techniques investigated makes the HIM a powerful nanoscale dimensional metrology tool, with the capability of both fabricating and imaging features with sub-nanometre resolution.
Selective Interaction in a Polymer−Single-Wall Carbon Nanotube Composite
Publisher: American Chemical Society (ACS)
Date: 18-12-2002
DOI: 10.1021/JP026470S
Carbon Nanotube Composites as Efficient Charge Transport Media in Organic Optoelectronic Devices
Publisher: SPIE
Date: 17-03-2003
DOI: 10.1117/12.463921
Prognostic Implications of Raphe in Bicuspid Aortic Valve Anatomy
Publisher: American Medical Association (AMA)
Date: 03-2017
DOI: 10.1001/JAMACARDIO.2016.5228
Abstract: Little is known about the association between bicuspid aortic valve (BAV) morphologic findings and the degree of valvular dysfunction, presence of aortopathy, and complications, including aortic valve surgery, aortic dissection, and all-cause mortality. To investigate the association between BAV morphologic findings (raphe vs nonraphe) and the degree of valve dysfunction, presence of aortopathy, and prognosis (including need for aortic valve surgery, aortic dissection, and all-cause mortality). In this large international multicenter registry of patients with BAV treated at tertiary referral centers, 2118 patients with BAV were evaluated. Patients referred for echocardiography from June 1, 1991, through November 31, 2015, were included in the study. Clinical and echocardiographic data were analyzed retrospectively. The morphologic BAV findings were categorized according to the Sievers and Schmidtke classification. Aortic valve function was ided into normal, regurgitation, or stenosis. Patterns of BAV aortopathy included the following: type 1, dilation of the ascending aorta and aortic root type 2, isolated dilation of the ascending aorta and type 3, isolated dilation of the sinus of Valsalva and/or sinotubular junction. Association between the presence and location of raphe and the risk of significant (moderate and severe) aortic valve dysfunction and aortic dilation and/or dissection. Of the 2118 patients (mean [SD] age, 47 [18] years 1525 [72.0%] male), 1881 (88.8%) had BAV with fusion raphe, whereas 237 (11.2%) had BAV without raphe. Bicuspid aortic valves with raphe had a significantly higher prevalence of valve dysfunction, with a significantly higher frequency of aortic regurgitation (622 [33.1%] vs 57 [24.1%], P < .001) and aortic stenosis (728 [38.7%] vs 51 [21.5%], P < .001). Furthermore, aortic valve replacement event rates were significantly higher among patients with BAV with raphe (364 [19.9%] at 1 year, 393 [21.4%] at 2 years, and 447 [24.4%] at 5 years) vs patients without raphe (30 [14.0%] at 1 year, 32 [15.0%] at 2 years, and 40 [18.0%] at 5 years) (P = .02). In addition, the all-cause mortality event rates were significantly higher among patients with BAV with raphe (77 [5.1%] at 1 year, 87 [6.2%] at 2 years, and 110 [9.5%] at 5 years) vs patients without raphe (2 [1.8%] at 1 year, 3 [3.0%] at 2 years, and 5 [4.4%] at 5 years) (P = .03). However, on multivariable analysis, the presence of raphe was not significantly associated with all-cause mortality. In this large multicenter, international BAV registry, the presence of raphe was associated with a higher prevalence of significant aortic stenosis and regurgitation. The presence of raphe was also associated with increased rates of aortic valve and aortic surgery. Although patients with BAV and raphe had higher mortality rates than patients without, the presence of a raphe was not independently associated with increased all-cause mortality.
Tunable nonlinear refractive index of two-dimensional MoS_2, WS_2, and MoSe_2 nanosheet dispersions [Invited]
Publisher: The Optical Society
Date: 26-03-2015
DOI: 10.1364/PRJ.3.000A51
Distributed response analysis of conductive behavior in single molecules
Publisher: Proceedings of the National Academy of Sciences
Date: 30-04-2002
Abstract: The ab initio computational approach of distributed response analysis is used to quantify how electrons move across conjugated molecules in an electric field, in analogy to conduction. The method promises to be valuable for characterizing the conductive behavior of single molecules in electronic devices.
Nitrogen assisted etching of graphene layers in a scanning electron microscope
Publisher: AIP Publishing
Date: 13-06-2011
DOI: 10.1063/1.3601467
Abstract: We describe the controlled patterning of nanopores in graphene layers by using the low-energy (& keV) focused electron beam in a scanning electron microscope. Regular nanometer-sized holes can be fabricated with the presence of nitrogen gas. The effect of the gas pressure, beam current, and energy on the etching process are investigated. Transmission electron microscopy, coupled with plasmon energy loss imaging, reveals the microstructure modification of the etched graphene. A nitrogen-ion assisted etching mechanism is proposed for the controlled patterning.
Optimisation of the arc-discharge production of multi-walled carbon nanotubes
Publisher: Elsevier BV
Date: 05-2002
Nonlinear photoluminescence in multiwall carbon nanotubes
Publisher: Elsevier BV
Date: 03-2001
Nonlinear photoluminescence from multiwalled carbon nanotubes
Publisher: SPIE
Date: 07-12-2001
DOI: 10.1117/12.449851
Noncontrast cardiac computed tomography‐derived mitral annular calcification scores in mitral valve disease
Publisher: Wiley
Date: 04-08-2023
DOI: 10.1002/CLC.24110
Abstract: Mitral annular calcification (MAC) by computed tomography (CT) is reported as an independent predictor of poor outcomes. However, it currently remains unclear if quantitative MAC parameters provide more value for mitral valve disease (MVD) management, therefore, we examined the prognostic value of MAC scores using noncontrast cardiac‐CT in MVD patients. Between January 2020 and December 2021, we prospectively enrolled 300 consecutive patients with MVD (MAC‐present = 80 and MAC‐absent = 220) undergoing preoperative cardiac‐CT and mitral valve (MV) surgery. Noncontrast cardiac‐CT images were used to qualitatively detect MAC (present or absent) and evaluate MAC scores. For analyses, we also collected baseline clinical data, intraoperative conversion (from MV repair to MV replacement), and follow‐up arrhythmia data. Compared with the MAC‐absent group, MAC‐present patients were older (62 ± 7 vs. 58 ± 9 years, p .001), mostly women (55% vs. 39.5%, p = .017), and also had aortic valve calcification (57.5% vs. 23.2%, p .001), mitral stenosis (82.5% vs. 61.8%, p .001), atrial fibrillation (30% vs. 11.8%, p .001), and larger left atrial end‐diastolic dimension (LADD, 49 [44–56] versus 46 [41–50], p = .001]. Furthermore, MAC‐present patients underwent more MV replacements (61.8% vs. 82.5%, p = .001) and experienced a higher intraoperative conversion prevalence (11.8% vs. 61.3%, p .001). Multiple logistic regression analyses showed that the female gender (odds ratio [OR]/95% confidence interval [CI]/ p = 2.001/1.042–3.841/0.037) and MAC scores (OR/95% CI/ p = 10.153/4.434–23.253/ p .001) were independent predictors of intraoperative conversion. During a follow‐up of 263 ± 134 days, MAC‐present patients had more arrhythmias (42.5% vs. 9.5%, p .001). Also, MAC‐scores (hazard ratio [HR]/95% CI/ p = 6.841/3.322–14.089/ p .001) and LADD (HR/95% CI/ p = 1.039/1.018–1.060/ p .001) were independently associated with arrhythmias by Cox regression analyses. Noncontrast cardiac CT‐derived MAC‐scores showed a high risk for intraoperative conversion and follow‐up arrhythmias in MVD‐patients.
Ultrafast Saturable Absorption of Two-Dimensional MoS2 Nanosheets
Publisher: American Chemical Society (ACS)
Date: 07-10-2013
DOI: 10.1021/NN403886T
Abstract: Employing high-yield production of layered materials by liquid-phase exfoliation, molybdenum disulfide (MoS2) dispersions with large populations of single and few layers were prepared. Electron microscopy verified the high quality of the two-dimensional MoS2 nanostructures. Atomic force microscopy analysis revealed that ~39% of the MoS2 flakes had thicknesses of less than 5 nm. Linewidth and frequency difference of the E(1)2g and A1g Raman modes confirmed the effective reduction of flake thicknesses from the bulk MoS2 to the dispersions. Ultrafast nonlinear optical (NLO) properties were investigated using an open-aperture Z-scan technique. All experiments were performed using 100 fs pulses at 800 nm from a mode-locked Ti:sapphire laser. The MoS2 nanosheets exhibited significant saturable absorption (SA) for the femtosecond pulses, resulting in the third-order NLO susceptibility Imχ((3)) ~ 10(-15) esu, figure of merit ~10(-15) esu cm, and free-carrier absorption cross section ~10(-17) cm(2). Induced free carrier density and the relaxation time were estimated to be ~10(16) cm(-3) and ~30 fs, respectively. At the same excitation condition, the MoS2 dispersions show better SA response than the graphene dispersions.
Nanopatterning and Electrical Tuning of MoS2 Layers with a Subnanometer Helium Ion Beam
Publisher: American Chemical Society (ACS)
Date: 15-07-2015
DOI: 10.1021/ACS.NANOLETT.5B01673
Abstract: We report subnanometer modification enabled by an ultrafine helium ion beam. By adjusting ion dose and the beam profile, structural defects were controllably introduced in a few-layer molybdenum disulfide (MoS2) s le and its stoichiometry was modified by preferential sputtering of sulfur at a few-nanometer scale. Localized tuning of the resistivity of MoS2 was demonstrated and semiconducting, metallic-like, or insulating material was obtained by irradiation with different doses of He(+). Amorphous MoSx with metallic behavior has been demonstrated for the first time. Fabrication of MoS2 nanostructures with 7 nm dimensions and pristine crystal structure was also achieved. The damage at the edges of these nanostructures was typically confined to within 1 nm. Nanoribbons with widths as small as 1 nm were reproducibly fabricated. This nanoscale modification technique is a generalized approach that can be applied to various two-dimensional (2D) materials to produce a new range of 2D metamaterials.
Electronic Polarizability as the Fundamental Variable in the Dielectric Properties of Two-Dimensional Materials
Publisher: American Chemical Society (ACS)
Date: 31-12-2019
DOI: 10.1021/ACS.NANOLETT.9B02982
Abstract: The dielectric constant, which defines the polarization of the media, is a key quantity in condensed matter. It determines several electronic and optoelectronic properties important for a plethora of modern technologies from computer memory to field effect transistors and communication circuits. Moreover, the importance of the dielectric constant in describing electromagnetic interactions through screening plays a critical role in understanding fundamental molecular interactions. Here, we show that despite its fundamental transcendence, the dielectric constant does not define unequivocally the dielectric properties of two-dimensional (2D) materials due to the locality of their electrostatic screening. Instead, the electronic polarizability correctly captures the dielectric nature of a 2D material which is united to other physical quantities in an atomically thin layer. We reveal a long-sought universal formalism where electronic, geometrical, and dielectric properties are intrinsically correlated through the polarizability, opening the door to probe quantities yet not directly measurable including the real covalent thickness of a layer. We unify the concept of dielectric properties in any material dimension finding a global dielectric anisotropy index defining their controllability through dimensionality.
Sub-5 nm graphene nanopore fabrication by nitrogen ion etching induced by a low-energy electron beam
Publisher: IOP Publishing
Date: 04-04-2016
DOI: 10.1088/0957-4484/27/19/195302
Abstract: A flexible and efficient method to fabricate nanopores in graphene has been developed. A focused, low-energy (5 keV) electron beam was used to locally activate etching of a graphene surface in a low pressure (0.3 Pa) N2 environment. Nanopores with sub-5 nm diameters were fabricated. The lattice structure of the graphene was observed to recover within 20 nm of the nanopore edge. Nanopore growth rates were investigated systematically. The effects of nitrogen pressure, electron beam dwell time and beam current were characterised in order to understand the etching mechanism and enable optimisation of the etching parameters. A model was developed which describes how the diffusion of ionised nitrogen affects the nanopore growth rate. Etching of other two-dimensional materials was attempted as demonstrated with MoS2. The lack of etching observed supports our model of a chemical reaction-based mechanism. The understanding of the etching mechanism will allow more materials to be etched by selection of an appropriate ion species.
Association Between Diffuse Myocardial Fibrosis by Cardiac Magnetic Resonance Contrast-Enhanced T 1 Mapping and Subclinical Myocardial Dysfunction in Diabetic Patien
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2012
DOI: 10.1161/CIRCIMAGING.111.965608
Abstract: Diabetic patients have increased interstitial myocardial fibrosis on histological examination. Magnetic resonance imaging (MRI) T 1 mapping is a previously validated imaging technique that can quantify the burden of global and regional interstitial fibrosis. However, the association between MRI T 1 mapping and subtle left ventricular (LV) dysfunction in diabetic patients is unknown. Fifty diabetic patients with normal LV ejection fraction (EF) and no underlying coronary artery disease or regional macroscopic scar on MRI delayed enhancement were prospectively recruited. Diabetic patients were compared with 19 healthy controls who were frequency matched in age, sex and body mass index. There were no significant differences in mean LV end-diastolic volume index, end-systolic volume index and LVEF between diabetic patients and healthy controls. Diabetic patients had significantly shorter global contrast-enhanced myocardial T 1 time (425±72 ms vs. 504±34 ms, P .001). There was no correlation between global contrast-enhanced myocardial T 1 time and LVEF ( r =0.14, P =0.32) in the diabetic patients. However, there was good correlation between global contrast-enhanced myocardial T 1 time and global longitudinal strain ( r =−0.73, P .001). Global contrast-enhanced myocardial T 1 time was the strongest independent determinant of global longitudinal strain on multivariate analysis (standardized β=−0.626, P .001). Similarly, there was good correlation between global contrast-enhanced myocardial T 1 time and septal E′ ( r =0.54, P .001). Global contrast-enhanced myocardial T 1 time was also the strongest independent determinant of septal E′ (standardized β=0.432, P .001). A shorter global contrast-enhanced myocardial T 1 time was associated with more impaired longitudinal myocardial systolic and diastolic function in diabetic patients.
Related Organisations
Key Laboratory Of Cardiovascular Imaging And Research Of Liaoning Province
Location: China
Related Funding Activities
No related grants have been discovered for Enno Tjeerd van der Velde.