Publications by authors named "Kristian Thygesen"

154 Publications

Let the Buyer (Clinician) Beware.

J Am Coll Cardiol 2021 Mar;77(12):1500-1502

Aarhus University Hospital, Aarhus, Denmark.

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http://dx.doi.org/10.1016/j.jacc.2021.02.031DOI Listing
March 2021

Two-Dimensional Materials with Giant Optical Nonlinearities near the Theoretical Upper Limit.

ACS Nano 2021 Mar 16. Epub 2021 Mar 16.

Department of Materials and Production, Aalborg University, 9220 Aalborg Øst, Denmark.

Nonlinear optical (NLO) phenomena such as harmonic generation and Kerr and Pockels effects are of great technological importance for lasers, frequency converters, modulators, switches, . Recently, two-dimensional (2D) materials have drawn significant attention due to their strong and peculiar NLO properties. Here, we describe an efficient first-principles workflow for calculating the quadratic optical response and apply it to 375 non-centrosymmetric semiconductor monolayers from the Computational 2D Materials Database (C2DB). Sorting the nonresonant nonlinearities with respect to bandgap reveals an upper limit proportional to , which is neatly explained by two distinct generic models. We identify multiple promising candidates with giant nonlinearities and bandgaps ranging from 0.4 to 5 eV, some of which approach the theoretical upper limit and greatly outperform known materials. Our comprehensive library of NLO spectra for all 375 monolayers is freely available the C2DB Web site.
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http://dx.doi.org/10.1021/acsnano.1c00344DOI Listing
March 2021

Cardiovascular biomarkers in patients with COVID-19.

Eur Heart J Acute Cardiovasc Care 2021 Feb 28. Epub 2021 Feb 28.

Department of Medical Sciences, Uppsala University, Uppsala, Sweden.

The coronavirus disease 2019 (COVID-19) pandemic has increased awareness that severe acute respiratory distress syndrome coronavirus-2 (SARS-CoV-2) may have profound effects on the cardiovascular system. COVID-19 often affects patients with pre-existing cardiac disease, and may trigger acute respiratory distress syndrome (ARDS), venous thromboembolism (VTE), acute myocardial infarction (AMI), and acute heart failure (AHF). However, as COVID-19 is primarily a respiratory infectious disease, there remain substantial uncertainty and controversy whether and how cardiovascular biomarkers should be used in patients with suspected COVID-19. To help clinicians understand the possible value as well as the most appropriate interpretation of cardiovascular biomarkers in COVID-19, it is important to highlight that recent findings regarding the prognostic role of cardiovascular biomarkers in patients hospitalized with COVID-19 are similar to those obtained in studies for pneumonia and ARDS in general. Cardiovascular biomarkers reflecting pathophysiological processes involved in COVID-19/pneumonia and its complications have a role evaluating disease severity, cardiac involvement, and risk of death in COVID-19 as well as in pneumonias caused by other pathogens. First, cardiomyocyte injury, as quantified by cardiac troponin concentrations, and haemodynamic cardiac stress, as quantified by natriuretic peptide concentrations, may occur in COVID-19 as in other pneumonias. The level of those biomarkers correlates with disease severity and mortality. Interpretation of cardiac troponin and natriuretic peptide concentrations as quantitative variables may aid in risk stratification in COVID-19/pneumonia and also will ensure that these biomarkers maintain high diagnostic accuracy for AMI and AHF. Second, activated coagulation as quantified by D-dimers seems more prominent in COVID-19 as in other pneumonias. Due to the central role of endothelitis and VTE in COVID-19, serial measurements of D-dimers may help physicians in the selection of patients for VTE imaging and the intensification of the level of anticoagulation from prophylactic to slightly higher or even therapeutic doses.
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http://dx.doi.org/10.1093/ehjacc/zuab009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7989520PMC
February 2021

Biomarkers of coagulation and fibrinolysis in acute myocardial infarction: a joint position paper of the Association for Acute CardioVascular Care and the European Society of Cardiology Working Group on Thrombosis.

Eur Heart J Acute Cardiovasc Care 2020 Nov 7. Epub 2020 Nov 7.

Department of Cardiology, Aarhus University Hospital, Palle Juul-Jensens Blvd. 161, 8200 Aarhus N, Denmark.

The formation of a thrombus in an epicardial artery may result in an acute myocardial infarction (AMI). Despite major advances in acute treatment using network approaches to allocate patients to timely reperfusion and optimal antithrombotic treatment, patients remain at high risk for thrombotic complications. Ongoing activation of the coagulation system as well as thrombin-mediated platelet activation may both play a crucial role in this context. Whether measurement of circulating biomarkers of coagulation and fibrinolysis could be useful for risk stratification in secondary prevention is currently not fully understood. In addition, measurement of such biomarkers could be helpful to identify thrombus formation as the leading mechanism for AMI. The introduction of biomarkers of myocardial injury such as high-sensitivity cardiac troponins made rule-out of AMI even more precise. However, elevated markers of myocardial injury cannot provide proof of a type 1 AMI, let alone thrombus formation. The combined measurement of markers of myocardial injury with biomarkers reflecting ongoing thrombus formation might be helpful for the fast and correct diagnosis of an atherothrombotic type 1 AMI. This position paper gives an overview of the current knowledge and possible role of biomarkers of coagulation and fibrinolysis for the diagnosis of AMI, risk stratification, and individualized treatment strategies in patients with AMI.
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http://dx.doi.org/10.1093/ehjacc/zuaa025DOI Listing
November 2020

Adjusting the MI Codes Into the Framework of the Universal Definition of Myocardial Infarction.

J Am Coll Cardiol 2021 Feb;77(7):858-860

Department of Medicine and Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA.

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http://dx.doi.org/10.1016/j.jacc.2021.01.003DOI Listing
February 2021

Intrinsic Defects in MoS Grown by Pulsed Laser Deposition: From Monolayers to Bilayers.

ACS Nano 2021 Feb 12;15(2):2858-2868. Epub 2021 Feb 12.

Department of Photonics Engineering, Technical University of Denmark, 4000 Roskilde, Denmark.

Pulsed laser deposition (PLD) can be considered a powerful method for the growth of two-dimensional (2D) transition-metal dichalcogenides (TMDs) into van der Waals heterostructures. However, despite significant progress, the defects in 2D TMDs grown by PLD remain largely unknown and yet to be explored. Here, we combine atomic resolution images and first-principles calculations to reveal the atomic structure of defects, grains, and grain boundaries in mono- and bilayer MoS grown by PLD. We find that sulfur vacancies and Mo antisites are the predominant point defects in 2D MoS. We predict that the aforementioned point defects are thermodynamically favorable under a Mo-rich/S-poor environment. The MoS monolayers are polycrystalline and feature nanometer size grains connected by a high density of grain boundaries. In particular, the coalescence of nanometer grains results in the formation of 180° mirror twin boundaries consisting of distinct 4- and 8-membered rings. We show that PLD synthesis of bilayer MoS results in various structural symmetries, including AA' and AB, but also turbostratic with characteristic moiré patterns. Moreover, we report on the experimental demonstration of an electron beam-driven transition between the AB and AA' stacking orientations in bilayer MoS. These results provide a detailed insight into the atomic structure of monolayer MoS and the role of the grain boundaries on the growth of bilayer MoS, which has importance for future applications in optoelectronics.
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http://dx.doi.org/10.1021/acsnano.0c08835DOI Listing
February 2021

Myocardial Infarction in the ISCHEMIA Trial: Impact of Different Definitions on Incidence, Prognosis, and Treatment Comparisons.

Circulation 2021 Feb 3;143(8):790-804. Epub 2020 Dec 3.

New York University Grossman School of Medicine, New York (J.S.B., H.R.R., S.B., J.S.H.).

Background: In the ISCHEMIA trial (International Study of Comparative Health Effectiveness with Medical and Invasive Approaches), an initial invasive strategy did not significantly reduce rates of cardiovascular events or all-cause mortality in comparison with a conservative strategy in patients with stable ischemic heart disease and moderate/severe myocardial ischemia. The most frequent component of composite cardiovascular end points was myocardial infarction (MI).

Methods: ISCHEMIA prespecified that the primary and major secondary composite end points of the trial be analyzed using 2 MI definitions. For procedural MI, the primary MI definition used creatine kinase-MB as the preferred biomarker, whereas the secondary definition used cardiac troponin. Procedural thresholds were >5 times the upper reference level for percutaneous coronary intervention and >10 times for coronary artery bypass grafting. Procedural MI definitions included (1) a category of elevated biomarker only events with much higher biomarker thresholds, (2) new ST-segment depression of ≥1 mm for the primary and ≥0.5 mm for the secondary definition, and (3) new coronary dissections National Heart, Lung, and Blood Institute grade 3. We compared MI type, frequency, and prognosis by treatment assignment using both MI definitions.

Results: Procedural MIs accounted for 20.1% of all MI events with the primary definition and 40.6% of all MI events with the secondary definition. Four-year MI rates in patients undergoing revascularization were more frequent with the invasive versus conservative strategy using the primary (2.7% versus 1.1%; adjusted hazard ratio [HR], 2.98 [95% CI, 1.87-4.73]) and secondary (8.2% versus 2.0%; adjusted HR, 5.04 [95% CI, 3.64-6.97]) MI definitions. Type 1 MIs were less frequent with the invasive versus conservative strategy using the primary (3.40% versus 6.89%; adjusted HR, 0.53 [95% CI, 0.41-0.69]; <0.0001) and secondary (3.48% versus 6.89%; adjusted HR, 0.53 [95% CI, 0.41-0.69]; <0.0001) definitions. The risk of subsequent cardiovascular death was higher after a type 1 MI than after no MI using the primary (adjusted HR, 3.38 [95% CI, 2.03-5.61]; <0.001) or secondary MI definition (adjusted HR, 3.52 [2.11-5.88]; <0.001).

Conclusions: In ISCHEMIA, type 1 MI events using the primary and secondary definitions during 5-year follow-up were more frequent with an initial conservative strategy and associated with subsequent cardiovascular death. Procedural MI rates were greater in the invasive strategy and with the use of the secondary MI definition. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01471522.
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http://dx.doi.org/10.1161/CIRCULATIONAHA.120.047987DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7902479PMC
February 2021

Cardiac procedural myocardial injury, infarction, and mortality in patients undergoing elective percutaneous coronary intervention: a pooled analysis of patient-level data.

Eur Heart J 2021 Jan;42(4):323-334

The Hatter Cardiovascular Institute, University College London, London, UK.

Aims: The prognostic importance of cardiac procedural myocardial injury and myocardial infarction (MI) in chronic coronary syndrome (CCS) patients undergoing elective percutaneous coronary intervention (PCI) is still debated.

Methods And Results: We analysed individual data of 9081 patients undergoing elective PCI with normal pre-PCI baseline cardiac troponin (cTn) levels. Multivariate models evaluated the association between post-PCI elevations in cTn and 1-year mortality, while an interval analysis evaluated the impact of the size of the myocardial injury on mortality. Our analysis was performed in the overall population and also according to the type of cTn used [52.0% had high-sensitivity cTn (hs-cTn)]. Procedural myocardial injury, as defined by the Fourth Universal Definition of MI (UDMI) [post-PCI cTn elevation ≥1 × 99th percentile upper reference limit (URL)], occurred in 52.8% of patients and was not associated with 1-year mortality [adj odds ratio (OR), 1.35, 95% confidence interval (CI) (0.84-1.77), P = 0.21]. The association between post-PCI cTn elevation and 1-year mortality was significant starting ≥3 × 99th percentile URL. Major myocardial injury defined by post-PCI ≥5 × 99th percentile URL occurred in 18.2% of patients and was associated with a two-fold increase in the adjusted odds of 1-year mortality [2.29, 95% CI (1.32-3.97), P = 0.004]. In the subset of patients for whom periprocedural evidence of ischaemia was collected (n = 2316), Type 4a MI defined by the Fourth UDMI occurred in 12.7% of patients and was strongly associated with 1-year mortality [adj OR 3.21, 95% CI (1.42-7.27), P = 0.005]. We also present our results according to the type of troponin used (hs-cTn or conventional troponin).

Conclusion: Our analysis has demonstrated that in CCS patients with normal baseline cTn levels, the post-PCI cTn elevation of ≥5 × 99th percentile URL used to define Type 4a MI is associated with 1-year mortality and could be used to detect 'major' procedural myocardial injury in the absence of procedural complications or evidence of new myocardial ischaemia.
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http://dx.doi.org/10.1093/eurheartj/ehaa885DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7850039PMC
January 2021

Engineering Dielectric Screening for Potential-well Arrays of Excitons in 2D Materials.

ACS Appl Mater Interfaces 2020 Dec 24;12(49):55134-55140. Epub 2020 Nov 24.

Centre for Graphene Science, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QL, U.K.

Tailoring of the band gap in semiconductors is essential for the development of novel devices. In standard semiconductors, this modulation is generally achieved through highly energetic ion implantation. In two-dimensional (2D) materials, the photophysical properties are strongly sensitive to the surrounding dielectric environment presenting novel opportunities through van der Waals heterostructures encompassing atomically thin high-κ dielectrics. Here, we demonstrate a giant tuning of the exciton binding energy of the monolayer WSe as a function of the dielectric environment. Upon increasing the average dielectric constant from 2.4 to 15, the exciton binding energy is reduced by as much as 300 meV in ambient conditions. The experimentally determined exciton binding energies are in excellent agreement with the theoretical values predicted from a Mott-Wannier exciton model with parameters derived from first-principles calculations. Finally, we show how texturing of the dielectric environment can be used to realize potential-well arrays for excitons in 2D materials, which is a first step toward exciton metamaterials.
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http://dx.doi.org/10.1021/acsami.0c14696DOI Listing
December 2020

High oscillator strength interlayer excitons in two-dimensional heterostructures for mid-infrared photodetection.

Nat Nanotechnol 2020 Aug 29;15(8):675-682. Epub 2020 Jun 29.

Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.

The development of infrared photodetectors is mainly limited by the choice of available materials and the intricate crystal growth process. Moreover, thermally activated carriers in traditional III-V and II-VI semiconductors enforce low operating temperatures in the infrared photodetectors. Here we demonstrate infrared photodetection enabled by interlayer excitons (ILEs) generated between tungsten and hafnium disulfide, WS/HfS. The photodetector operates at room temperature and shows an even higher performance at higher temperatures owing to the large exciton binding energy and phonon-assisted optical transition. The unique band alignment in the WS/HfS heterostructure allows interlayer bandgap tuning from the mid- to long-wave infrared spectrum. We postulate that the sizeable charge delocalization and ILE accumulation at the interface result in a greatly enhanced oscillator strength of the ILEs and a high responsivity of the photodetector. The sensitivity of ILEs to the thickness of two-dimensional materials and the external field provides an excellent platform to realize robust tunable room temperature infrared photodetectors.
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http://dx.doi.org/10.1038/s41565-020-0717-2DOI Listing
August 2020

A library of ab initio Raman spectra for automated identification of 2D materials.

Nat Commun 2020 Jun 15;11(1):3011. Epub 2020 Jun 15.

Computational Atomic-scale Materials Design (CAMD), Department of Physics, Technical University of Denmark (DTU), Lyngby, 2800 Kgs, Denmark.

Raman spectroscopy is frequently used to identify composition, structure and layer thickness of 2D materials. Here, we describe an efficient first-principles workflow for calculating resonant first-order Raman spectra of solids within third-order perturbation theory employing a localized atomic orbital basis set. The method is used to obtain the Raman spectra of 733 different monolayers selected from the Computational 2D Materials Database (C2DB). We benchmark the computational scheme against available experimental data for 15 known monolayers. Furthermore, we propose an automatic procedure for identifying a material based on an input experimental Raman spectrum and apply it to the cases of MoS (H-phase) and WTe (T[Formula: see text]-phase). The Raman spectra of all materials at different excitation frequencies and polarization configurations are freely available from the C2DB. Our comprehensive and easily accessible library of ab initio Raman spectra should be valuable for both theoreticians and experimentalists in the field of 2D materials.
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http://dx.doi.org/10.1038/s41467-020-16529-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7296020PMC
June 2020

Engineering covalently bonded 2D layered materials by self-intercalation.

Nature 2020 05 13;581(7807):171-177. Epub 2020 May 13.

Department of Chemistry and Centre for Advanced 2D Materials, National University of Singapore, Singapore, Singapore.

Two-dimensional (2D) materials offer a unique platform from which to explore the physics of topology and many-body phenomena. New properties can be generated by filling the van der Waals gap of 2D materials with intercalants; however, post-growth intercalation has usually been limited to alkali metals. Here we show that the self-intercalation of native atoms into bilayer transition metal dichalcogenides during growth generates a class of ultrathin, covalently bonded materials, which we name ic-2D. The stoichiometry of these materials is defined by periodic occupancy patterns of the octahedral vacancy sites in the van der Waals gap, and their properties can be tuned by varying the coverage and the spatial arrangement of the filled sites. By performing growth under high metal chemical potential we can access a range of tantalum-intercalated TaS(Se), including 25% Ta-intercalated TaS, 33.3% Ta-intercalated TaS, 50% Ta-intercalated TaS, 66.7% Ta-intercalated TaSe (which forms a Kagome lattice) and 100% Ta-intercalated TaSe. Ferromagnetic order was detected in some of these intercalated phases. We also demonstrate that self-intercalated VS, InSe and FeTe can be grown under metal-rich conditions. Our work establishes self-intercalation as an approach through which to grow a new class of 2D materials with stoichiometry- or composition-dependent properties.
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http://dx.doi.org/10.1038/s41586-020-2241-9DOI Listing
May 2020

The Universal Definition of Myocardial Infarction: Present and Future.

Circulation 2020 May 4;141(18):1434-1436. Epub 2020 May 4.

Departments of Cardiovascular Diseases (S.Y., A.S.J.), Mayo Clinic, Rochester, MN.

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http://dx.doi.org/10.1161/CIRCULATIONAHA.120.045708DOI Listing
May 2020

Application of the fourth universal definition of myocardial infarction in clinical practice.

Biomarkers 2020 Jun 14;25(4):322-330. Epub 2020 May 14.

Department of Medical Sciences, Uppsala University and Uppsala Clinical Research Center, Uppsala University, Sweden.

The Fourth Universal Definition of Myocardial Infarction (MI) has highlighted the different pathophysiological mechanisms that may lead to ischaemic and non-ischaemic myocardial injury and has emphasised that the diagnosis of myocardial infarction requires the presence of acute myocardial ischaemia in the setting of acute myocardial injury. This case based review intends to illustrate basic principles on how to apply this new, revised definition in clinical practice. The distinction between different types of MIs (type 1 or type 2) and the delineation of MI from acute non-ischaemic myocardial injury may be challenging in individual patients, which is illustrated by presenting and discussing real-life routine cases. Type 1 MI is a consequence of coronary plaque rupture or erosion with intracoronary thrombus formation that is usually apparent on coronary angiography. Plausible triggering mechanisms causing myocardial oxygen supply/demand mismatch must be identified for the diagnosis of type 2 MI and its treatment should focus initially on management of the underlying disease attributable to acute myocardial ischaemia.
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http://dx.doi.org/10.1080/1354750X.2020.1764108DOI Listing
June 2020

Our nearly complete diagnostic trip of thousands of steps begets a new trip therapeutically.

Eur Heart J 2020 06;41(23):2217-2219

Mayo Clinic, Rochester, MN, USA.

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http://dx.doi.org/10.1093/eurheartj/ehaa154DOI Listing
June 2020

The Gloomy Long-Term Prognosis of Patients With Type 2 Myocardial Infarction or Myocardial Injury.

J Am Coll Cardiol 2020 03;75(9):1014-1016

Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota.

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http://dx.doi.org/10.1016/j.jacc.2020.01.004DOI Listing
March 2020

Classifying the Electronic and Optical Properties of Janus Monolayers.

ACS Nano 2019 Nov 22;13(11):13354-13364. Epub 2019 Oct 22.

Computational Atomic-scale Materials Design (CAMD), Department of Physics , Technical University of Denmark , DK-2800 Kongens Lyngby , Denmark.

Inspired by the recent synthesis of monolayer MoSSe, we conduct a first-principles high-throughput investigation of 216 MXY Janus monolayers consisting of a middle layer of metal atoms (M) sandwiched between different types of chalcogen, halogen, or pnictogen atoms (X,Y). Using density functional theory and many-body perturbation theory, we perform an exhaustive computational characterization of the 70 most stable semiconducting monolayers. These are found to exhibit diverse and fascinating properties including finite out-of-plane dipoles, giant Rashba-splittings, direct and indirect band gaps ranging from 0.7 to 3.0 eV, large exciton binding energies, and very strong light-matter interactions. The data have been generated using the workflow behind the Computational 2D Materials Database and are freely available online. Our work expands the class of known Janus monolayers and points to several potentially synthesizable structures, which could be interesting candidates for valley- or optoelectronic applications or for generating out-of-plane electric fields to control charge transfer, charge separation, or band alignments in van der Waals heterostructures.
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http://dx.doi.org/10.1021/acsnano.9b06698DOI Listing
November 2019

Cardiac Myosin-Binding Protein C to Diagnose Acute Myocardial Infarction in the Pre-Hospital Setting.

J Am Heart Assoc 2019 08 26;8(15):e013152. Epub 2019 Jul 26.

Department of Cardiology Aarhus University Hospital Aarhus Denmark.

Background Early triage is essential to improve outcomes in patients with suspected acute myocardial infarction (AMI). This study investigated whether cMyC (cardiac myosin-binding protein), a novel biomarker of myocardial necrosis, can aid early diagnosis of AMI and risk stratification. Methods and Results cMyC and high-sensitivity cardiac troponin T were retrospectively quantified in blood samples obtained by ambulance-based paramedics in a prospective, diagnostic cohort study. Patients with ongoing or prolonged periods of chest discomfort, acute dyspnoea in the absence of known pulmonary disease, or clinical suspicion of AMI were recruited. Discrimination power was evaluated by calculating the area under the receiver operating characteristics curve; diagnostic performance was assessed at predefined thresholds. Diagnostic nomograms were derived and validated using bootstrap resampling in logistic regression models. Seven hundred seventy-six patients with median age 68 [58;78] were recruited. AMI was the final adjudicated diagnosis in 22%. Median symptom to sampling time was 70 minutes. cMyC concentration in patients with AMI was significantly higher than with other diagnoses: 98 [43;855] versus 17 [9;42] ng/L. Discrimination power for AMI was better with cMyC than with high-sensitivity cardiac troponin T (area under the curve, 0.839 versus 0.813; P=0.005). At a previously published rule-out threshold (10 ng/L), cMyC reaches 100% sensitivity and negative predictive value in patients after 2 hours of symptoms. In logistic regression analysis, cMyC is superior to high-sensitivity cardiac troponin T and was used to derive diagnostic and prognostic nomograms to evaluate risk of AMI and death. Conclusions In patients undergoing blood draws very early after symptom onset, cMyC demonstrates improved diagnostic discrimination of AMI and could significantly improve the early triage of patients with suspected AMI.
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http://dx.doi.org/10.1161/JAHA.119.013152DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6761674PMC
August 2019

Should myocardial infarction type 2 be regarded as two separate entities?

Eur Heart J 2019 09;40(33):2810-2812

Mayo Clinic and Medical School, Rochester, MN, USA.

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http://dx.doi.org/10.1093/eurheartj/ehz451DOI Listing
September 2019

A Protocol for Fast Prediction of Electronic and Optical Properties of Donor-Acceptor Polymers Using Density Functional Theory and the Tight-Binding Method.

J Phys Chem A 2019 Jun 31;123(23):4980-4989. Epub 2019 May 31.

Department of Energy Conversion and Storage , Technical University of Denmark , 2800 Kgs. Lyngby , Denmark.

The ability of donor-acceptor (D-A) type polymers to control the positions of the highest occupied (HOMO) and lowest unoccupied (LUMO) molecular orbitals makes them a popular choice for organic solar cell applications. The alternating D-A pattern in a monomer leads to a weak electronic coupling between the constituent monomers within the polymer chain. Exploiting the weak electronic coupling characteristics, we developed a method to efficiently calculate (1) the electronic properties and (2) the optical gap of such polymer chains. The electronic properties (HOMO and LUMO energies, ionization potential, electron affinity, and quasiparticle gap of an oligomer of any length up to an infinitely long polymer) of the D-A polymers are predicted by combining density functional theory calculation results and a tight-binding model. The weak electronic coupling implies that the optical gap of the polymer is size-independent, and thus, it can be calculated using a monomer. We validated the methods using a set of 104 polymers by checking the consistency where the electronic gap of a polymer is larger than the optical gap. Furthermore, we establish relationships between the results obtained from more accurate, yet slower methods (i.e., B3LYP functional, singlet-ΔSCF) with those obtained from the faster counterparts (i.e., BLYP functional, triplet-ΔSCF). Leveraging the found relationships, we propose a way in which the electronic and optical properties of the polymers can be calculated efficiently while retaining high accuracy. The use of the tight-binding model combined with the approach to estimate more accurate results based on less expensive simulations is crucial in the applications where a large volume of computations needs to be carried out efficiently with sufficiently high accuracy, such as high-throughput computational screening or training a machine-learning model.
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http://dx.doi.org/10.1021/acs.jpca.9b02391DOI Listing
June 2019

'Ten Commandments' for the Fourth Universal Definition of Myocardial Infarction 2018.

Eur Heart J 2019 01;40(3):226

Joint ESC/ACC/AHA/WHF Task Force for the Universal Definition of Myocardial Infarction. Department of Cardiology, Aarhus University Hospital, Palle Juul-Jensens Boulevard, DK-8200 Aarhus N, Denmark.

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http://dx.doi.org/10.1093/eurheartj/ehy856DOI Listing
January 2019

What's new in the Fourth Universal Definition of Myocardial infarction?

Eur Heart J 2018 Nov;39(42):3757-3758

Joint ESC/ACC/AHA/WHF Task Force for the Universal Definition of Myocardial Infarction. Department of Cardiology, Aarhus University Hospital, Palle Juul-Jensens Boulevard, Aarhus N, Denmark, Tel: +45 78452262.

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http://dx.doi.org/10.1093/eurheartj/ehy655DOI Listing
November 2018

Stacked Janus Device Concepts: Abrupt pn-Junctions and Cross-Plane Channels.

Nano Lett 2018 11 19;18(11):7275-7281. Epub 2018 Oct 19.

Department of Micro- and Nanotechnology (DTU Nanotech) , Technical University of Denmark , DK-2800 Kgs. Lyngby , Denmark.

Janus transition metal dichalcogenides with a built-in structural cross-plane (cp) asymmetry have recently emerged as a new class of two-dimensional materials with a large cp dipole. Using first-principles calculations, and a tailored transport method, we demonstrate that stacking graphene and MoSSe Janus structures result in record high homogeneous doping of graphene and abrupt, atomically thin, cross-plane pn-junctions. We show how graphene in contrast to metals can act as electrodes to Janus stacks without screening the cp dipole and predict a large photocurrent response dominated by a cp transport channel in a few-layer stacked device. The photocurrent is above that of a corresponding thin-film silicon device illustrating the great potential of Janus stacks, for example, in photovoltaic devices.
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http://dx.doi.org/10.1021/acs.nanolett.8b03474DOI Listing
November 2018

Nano-imaging of intersubband transitions in van der Waals quantum wells.

Nat Nanotechnol 2018 11 27;13(11):1035-1041. Epub 2018 Aug 27.

ICFO - Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain.

The science and applications of electronics and optoelectronics have been driven for decades by progress in the growth of semiconducting heterostructures. Many applications in the infrared and terahertz frequency range exploit transitions between quantized states in semiconductor quantum wells (intersubband transitions). However, current quantum well devices are limited in functionality and versatility by diffusive interfaces and the requirement of lattice-matched growth conditions. Here, we introduce the concept of intersubband transitions in van der Waals quantum wells and report their first experimental observation. Van der Waals quantum wells are naturally formed by two-dimensional materials and hold unexplored potential to overcome the aforementioned limitations-they form atomically sharp interfaces and can easily be combined into heterostructures without lattice-matching restrictions. We employ near-field local probing to spectrally resolve intersubband transitions with a nanometre-scale spatial resolution and electrostatically control the absorption. This work enables the exploitation of intersubband transitions with unmatched design freedom and individual electronic and optical control suitable for photodetectors, light-emitting diodes and lasers.
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http://dx.doi.org/10.1038/s41565-018-0233-9DOI Listing
November 2018