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result(s) for
"Gerber, Robert T"
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A SENIOR moment? Bare-metal stents in elderly patients
by
Gershlick, Anthony H
,
Gerber, Robert T
in
Acute coronary syndromes
,
Angina pectoris
,
Cardiovascular disease
2018
In The Lancet, Olivier Varenne and colleagues 6 investigate use of a new thin-strut DES versus BMS in elderly patients (>=75 years) with a tailored curtailed antiplatelet approach in the SENIOR trial. DAPT was discontinued at 1 month in stable patients and at 6 months in patients with acute coronary syndrome regardless of having received either DES or BSM.
Journal Article
Comparison of One-Year Outcomes in Patients >75 Versus ≤75 Years With Coronary Artery Disease Treated With COMBO Stents (From The MASCOT Registry)
2020
Older patients who undergo coronary interventions are at greater risk of ischemic events and less likely to tolerate prolonged dual antiplatelet therapy (DAPT) due to bleeding risk. The COMBO biodegradable polymer sirolimus-eluting stent promotes rapid endothelialization through endothelial progenitor cell capture technology which may be advantageous in elderly patients. We compared 1-year clinical outcomes and DAPT cessation events in patients >75 versus ≤75 years from the MASCOT registry. MASCOT was a prospective, multicenter cohort study of all-comers undergoing attempted COMBO stenting. The primary endpoint was 1-year target lesion failure (TLF), composite of cardiac death, myocardial infarction (MI) not clearly attributed to a nontarget vessel or clinically driven target lesion revascularization. Bleeding was adjudicated using the Bleeding Academic Research Consortium criteria. Adjusted outcomes were analyzed using Cox regression methods. The study included 18% (n = 479) patients >75 years and 72% (n = 2,135) patients ≤75 years. One-year TLF occurred in 4.6% patients >75 years versus 3.1% patients ≤75years of age, p = 0.10; adj hazard ratio 1.36, 95% confidence intervals 0.77 to 2.38, p = 0.29. There were no significant differences in cardiac death (1.7% vs 1.3%, p = 0.55), MI (2.1% vs 1.2%, p = 0.14), target lesion revascularization (1.7% vs 1.4%, p = 0.60) and definite stent thrombosis (0.8% vs 0.4%, p = 0.19). Major Bleeding Academic Research Consortium 3,5 bleeding (3.1% vs 1.5%, p = 0.01) and DAPT cessation rates (32.4% vs 23.0%, p <0.001) were significantly higher in elderly patients. In conclusion, elderly patients >75 years treated with COMBO stents had similar TLF but significantly greater incidence of bleeding than younger patients and DAPT cessation in one-third of patients over 1 year.
Journal Article
75 Versus ≤75 Years With Coronary Artery Disease Treated With COMBO Stents (From The MASCOT Registry)
by
Mates, Martin
,
de Winter, Robbert J
,
Coufal, Zdeněk
in
Angina pectoris
,
Antiplatelet therapy
,
Biodegradability
2020
Older patients who undergo coronary interventions are at greater risk of ischemic events and less likely to tolerate prolonged dual antiplatelet therapy (DAPT) due to bleeding risk. The COMBO biodegradable polymer sirolimus-eluting stent promotes rapid endothelialization through endothelial progenitor cell capture technology which may be advantageous in elderly patients. We compared 1-year clinical outcomes and DAPT cessation events in patients >75 versus ≤75 years from the MASCOT registry. MASCOT was a prospective, multicenter cohort study of all-comers undergoing attempted COMBO stenting. The primary endpoint was 1-year target lesion failure (TLF), composite of cardiac death, myocardial infarction (MI) not clearly attributed to a nontarget vessel or clinically driven target lesion revascularization. Bleeding was adjudicated using the Bleeding Academic Research Consortium criteria. Adjusted outcomes were analyzed using Cox regression methods. The study included 18% (n = 479) patients >75 years and 72% (n = 2,135) patients ≤75 years. One-year TLF occurred in 4.6% patients >75 years versus 3.1% patients ≤75years of age, p = 0.10; adj hazard ratio 1.36, 95% confidence intervals 0.77 to 2.38, p = 0.29. There were no significant differences in cardiac death (1.7% vs 1.3%, p = 0.55), MI (2.1% vs 1.2%, p = 0.14), target lesion revascularization (1.7% vs 1.4%, p = 0.60) and definite stent thrombosis (0.8% vs 0.4%, p = 0.19). Major Bleeding Academic Research Consortium 3,5 bleeding (3.1% vs 1.5%, p = 0.01) and DAPT cessation rates (32.4% vs 23.0%, p <0.001) were significantly higher in elderly patients. In conclusion, elderly patients >75 years treated with COMBO stents had similar TLF but significantly greater incidence of bleeding than younger patients and DAPT cessation in one-third of patients over 1 year.
Journal Article
Renal artery sympathetic denervation: observations from the UK experience
by
Hameed, Awais
,
Lobo, Melvin D.
,
Mather, Adam N.
in
Aged
,
Antihypertensive Agents - therapeutic use
,
Blood Pressure - drug effects
2016
Background
Renal denervation (RDN) may lower blood pressure (BP); however, it is unclear whether medication changes may be confounding results. Furthermore, limited data exist on pattern of ambulatory blood pressure (ABP) response—particularly in those prescribed aldosterone antagonists at the time of RDN.
Methods
We examined all patients treated with RDN for treatment-resistant hypertension in 18 UK centres.
Results
Results from 253 patients treated with five technologies are shown. Pre-procedural mean office BP (OBP) was 185/102 mmHg (SD 26/19;
n
= 253) and mean daytime ABP was 170/98 mmHg (SD 22/16;
n
= 186). Median number of antihypertensive drugs was 5.0: 96 % ACEi/ARB; 86 % thiazide/loop diuretic and 55 % aldosterone antagonist. OBP, available in 90 % at 11 months follow-up, was 163/93 mmHg (reduction of 22/9 mmHg). ABP, available in 70 % at 8.5 months follow-up, was 158/91 mmHg (fall of 12/7 mmHg). Mean drug changes post RDN were: 0.36 drugs added, 0.91 withdrawn. Dose changes appeared neutral. Quartile analysis by starting ABP showed mean reductions in systolic ABP after RDN of: 0.4; 6.5; 14.5 and 22.1 mmHg, respectively (
p
< 0.001 for trend). Use of aldosterone antagonist did not predict response (
p
> 0.2).
Conclusion
In 253 patients treated with RDN, office BP fell by 22/9 mmHg. Ambulatory BP fell by 12/7 mmHg, though little response was seen in the lowermost quartile of starting blood pressure. Fall in BP was not explained by medication changes and aldosterone antagonist use did not affect response.
Journal Article
Controlling interlayer excitons in MoS2 layers grown by chemical vapor deposition
by
Warburton, Richard J.
,
Turchanin, Andrey
,
Urbaszek, Bernhard
in
119/118
,
140/125
,
639/301/119/1000/1018
2020
Combining MoS
2
monolayers to form multilayers allows to access new functionalities. Deterministic assembly of large area van der Waals structures requires concrete indicators of successful interlayer coupling in bilayers grown by chemical vapor deposition. In this work, we examine the correlation between the stacking order and the interlayer coupling of valence states in both as-grown MoS
2
homobilayer samples and in artificially stacked bilayers from monolayers, all grown by chemical vapor deposition. We show that hole delocalization over the bilayer is only allowed in 2H stacking and results in strong interlayer exciton absorption and also in a larger A-B exciton separation as compared to 3R bilayers. Comparing 2H and 3R reflectivity spectra allows to extract an interlayer coupling energy of about
t
⊥
= 49 meV. Beyond DFT calculations including excitonic effects confirm signatures of efficient interlayer coupling for 2H stacking in agreement with our experiments.
The authors investigate the interplay between the stacking order and the interlayer coupling in MoS
2
homobilayers as well as artificially stacked bilayers grown by chemical vapour deposition, and identify the interlayer exciton absorption and A-B exciton separation as indicators for interlayer coupling.
Journal Article
Spin-orbit engineering in transition metal dichalcogenide alloy monolayers
2015
Binary transition metal dichalcogenide monolayers share common properties such as a direct optical bandgap, spin-orbit splittings of hundreds of meV, light–matter interaction dominated by robust excitons and coupled spin-valley states. Here we demonstrate spin-orbit-engineering in Mo
(1−
x
)
W
x
Se
2
alloy monolayers for optoelectronics and applications based on spin- and valley-control. We probe the impact of the tuning of the conduction band spin-orbit spin-splitting on the bright versus dark exciton population. For MoSe
2
monolayers, the photoluminescence intensity decreases as a function of temperature by an order of magnitude (4–300 K), whereas for WSe
2
we measure surprisingly an order of magnitude increase. The ternary material shows a trend between these two extreme behaviours. We also show a non-linear increase of the valley polarization as a function of tungsten concentration, where 40% tungsten incorporation is sufficient to achieve valley polarization as high as in binary WSe
2
.
Single atomic layers of transition metal dichalcogenides are semiconductors with possible applications in spintronics. Here, the authors demonstrate tuning of the spin-orbit splitting in molybdenum tungsten diselenide by altering the alloy’s composition, impacting valley polarization and light emission yield.
Journal Article
Interlayer exciton mediated second harmonic generation in bilayer MoS2
by
Lagarde, Delphine
,
Balocchi, Andrea
,
Urbaszek, Bernhard
in
639/301/1019/385
,
639/301/119/1000/1018
,
Amplitudes
2021
Second-harmonic generation (SHG) is a non-linear optical process, where two photons coherently combine into one photon of twice their energy. Efficient SHG occurs for crystals with broken inversion symmetry, such as transition metal dichalcogenide monolayers. Here we show tuning of non-linear optical processes in an inversion symmetric crystal. This tunability is based on the unique properties of bilayer MoS
2
, that shows strong optical oscillator strength for the intra- but also interlayer exciton resonances. As we tune the SHG signal onto these resonances by varying the laser energy, the SHG amplitude is enhanced by several orders of magnitude. In the resonant case the bilayer SHG signal reaches amplitudes comparable to the off-resonant signal from a monolayer. In applied electric fields the interlayer exciton energies can be tuned due to their in-built electric dipole via the Stark effect. As a result the interlayer exciton degeneracy is lifted and the bilayer SHG response is further enhanced by an additional two orders of magnitude, well reproduced by our model calculations. Since interlayer exciton transitions are highly tunable also by choosing twist angle and material combination our results open up new approaches for designing the SHG response of layered materials.
Efficient second-harmonic generation (SHG) occurs for crystals with broken inversion symmetry, such as transition metal dichalcogenide monolayers. Here the authors show SHG tuning in bilayer MoS
2
- an inversion-symmetric crystal - mediated by interlayer excitons.
Journal Article
Giant Stark splitting of an exciton in bilayer MoS2
by
Cedric, Robert
,
Taniguchi, Takashi
,
Paradisanos Ioannis
in
Bilayers
,
Density functional theory
,
Electric dipoles
2020
Transition metal dichalcogenides (TMDs) constitute a versatile platform for atomically thin optoelectronics devices and spin–valley memory applications. In monolayer TMDs the optical absorption is strong, but the transition energy cannot be tuned as the neutral exciton has essentially no out-of-plane static electric dipole1,2. In contrast, interlayer exciton transitions in heterobilayers are widely tunable in applied electric fields, but their coupling to light is substantially reduced. In this work, we show tuning over 120 meV of interlayer excitons with a high oscillator strength in bilayer MoS2 due to the quantum-confined Stark effect3. We optically probed the interaction between intra- and interlayer excitons as they were energetically tuned into resonance. Interlayer excitons interact strongly with intralayer B excitons, as demonstrated by a clear avoided crossing, whereas the interaction with intralayer A excitons is substantially weaker. Our observations are supported by density functional theory (DFT) calculations, which include excitonic effects. In MoS2 trilayers, our experiments uncovered two types of interlayer excitons with and without in-built electric dipoles. Highly tunable excitonic transitions with large in-built dipoles and oscillator strengths will result in strong exciton–exciton interactions and therefore hold great promise for non-linear optics with polaritons.Interlayer excitons in bilayer MoS2 exhibit both a high oscillator strength and highly tunable energies in an applied electric field.
Journal Article
Non-Sinusoidal Activity Can Produce Cross-Frequency Coupling in Cortical Signals in the Absence of Functional Interaction between Neural Sources
by
Sadeh, Boaz
,
Gerber, Edden M.
,
Ward, Andrew
in
Analysis
,
Biology and Life Sciences
,
Brain - physiology
2016
The analysis of cross-frequency coupling (CFC) has become popular in studies involving intracranial and scalp EEG recordings in humans. It has been argued that some cases where CFC is mathematically present may not reflect an interaction of two distinct yet functionally coupled neural sources with different frequencies. Here we provide two empirical examples from intracranial recordings where CFC can be shown to be driven by the shape of a periodic waveform rather than by a functional interaction between distinct sources. Using simulations, we also present a generalized and realistic scenario where such coupling may arise. This scenario, which we term waveform-dependent CFC, arises when sharp waveforms (e.g., cortical potentials) occur throughout parts of the data, in particular if they occur rhythmically. Since the waveforms contain both low- and high-frequency components, these components can be inherently phase-aligned as long as the waveforms are spaced with appropriate intervals. We submit that such behavior of the data, which seems to be present in various cortical signals, cannot be interpreted as reflecting functional modulation between distinct neural sources without additional evidence. In addition, we show that even low amplitude periodic potentials that cannot be readily observed or controlled for, are sufficient for significant CFC to occur.
Journal Article
Magnetic imaging under high pressure with a spin-based quantum sensor integrated in a van der Waals heterostructure
2025
Pressure is a powerful tool for tuning the magnetic properties of van der Waals magnets owing to their weak interlayer bonding. However, local magnetometry measurements under high pressure still remain elusive for this important class of emerging materials. Here we demonstrate magnetic imaging of a van der Waals magnet under high pressure with sub-micron spatial resolution, using a two-dimensional (2D) quantum sensing platform based on boron-vacancy (
V
B
−
) centers in hexagonal boron nitride (hBN). We first analyze the performances of
V
B
−
centers in hBN for magnetic imaging under pressures up to few GPa, and we then use this 2D sensing platform to investigate the pressure-dependent magnetization in micrometer-sized flakes of 1
T
-CrTe
2
. Besides providing a new path for studying pressure-induced phase transitions in van der Waals magnets, this work also opens up interesting perspectives for exploring the physics of 2D superconductors under pressure via local measurements of the Meissner effect.
NV center-based quantum sensors integrated into diamond anvil cells have enabled magnetic imaging under high pressure but are less suited for studying magnetic van der Waals materials. Here, the authors demonstrate magnetic imaging of micrometer-sized flakes of 1T-CrTe2 under high pressure using spin-centers in a thin hBN layer.
Journal Article