Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 13 de 13
Filter
1.
Open Heart ; 11(1)2024 Jan 08.
Article in English | MEDLINE | ID: mdl-38191233

ABSTRACT

BACKGROUND: A quarter of patients with severe aortic stenosis (AS) were asymptomatic, and only a third of them survived at the end of 4 years. Only a select subset of these patients was recommended for aortic valve replacement (AVR) by the current American College of Cardiology/American Heart Association guidelines. We intended to study the effect of early AVR (eAVR) in this subset of asymptomatic patients with preserved left ventricle function. METHODS AND RESULTS: We searched PubMed and Embase for randomised and observational studies comparing the effect of eAVR versus conservative therapy in patients with severe, asymptomatic AS and normal left ventricular function. The primary outcome was all-cause mortality. The secondary outcomes were composite major adverse cardiac events (MACE) (study defined), myocardial infarction (MI), stroke, cardiac death, sudden death, the development of symptoms, heart failure hospitalisations and major bleeding. We used GRADEPro to assess the certainty of the evidence. In the randomised controlled trial (RCT) only analysis, we found no significant difference in all-cause mortality between the early aortic intervention group versus the conservative arm (CA) (incidence rate ratio, IRR (CI): 0.5 (0.2 to 1.1), I2=31%, p=0.09). However, in the overall cohort, we found mortality benefit for eAVR over CA (IRR (CI): 0.4 (0.3 to 0.7), I2=84%, p<0.01). There were significantly lower MACE, cardiac death, sudden death, development of symptoms and heart failure hospitalisations in the eAVR group. We noticed no difference in MI, stroke and major bleeding. CONCLUSION: We conclude that there is no reduction in all-cause mortality in the eAVR arm in patients with asymptomatic AS with preserved ejection fraction. However, eAVR reduces heart failure related hospitalisations and death or heart failure hospitalisations. PROSPERO REGISTRATION NUMBER: CRD42022306132.


Subject(s)
Aortic Valve Stenosis , Heart Valve Prosthesis Implantation , Humans , Aortic Valve/diagnostic imaging , Aortic Valve/surgery , Aortic Valve Stenosis/diagnosis , Aortic Valve Stenosis/surgery , Conservative Treatment/adverse effects , Death, Sudden, Cardiac/etiology , Heart Failure/etiology , Hemorrhage/etiology , Myocardial Infarction/etiology , Stroke/etiology , United States , Ventricular Function, Left , Heart Valve Prosthesis Implantation/adverse effects , Transcatheter Aortic Valve Replacement/adverse effects
2.
Chem Rev ; 123(13): 8154-8231, 2023 Jul 12.
Article in English | MEDLINE | ID: mdl-37276018

ABSTRACT

Halide perovskites (HPs) are potential game-changing materials for a broad spectrum of optoelectronic applications ranging from photovoltaics, light-emitting devices, lasers to radiation detectors, ferroelectrics, thermoelectrics, etc. Underpinning this spectacular expansion is their fascinating photophysics involving a complex interplay of carrier, lattice, and quasi-particle interactions spanning several temporal orders that give rise to their remarkable optical and electronic properties. Herein, we critically examine and distill their dynamical behavior, collective interactions, and underlying mechanisms in conjunction with the experimental approaches. This review aims to provide a unified photophysical picture fundamental to understanding the outstanding light-harvesting and light-emitting properties of HPs. The hotbed of carrier and quasi-particle interactions uncovered in HPs underscores the critical role of ultrafast spectroscopy and fundamental photophysics studies in advancing perovskite optoelectronics.

3.
Cardiovasc Revasc Med ; 54: 25-30, 2023 09.
Article in English | MEDLINE | ID: mdl-36842933

ABSTRACT

BACKGROUND: Patients with symptomatic calcified coronary lesions have poor outcomes. Such lesions require additional atherectomy devices for bed preparation. AIM: To assess the safety and efficacy of OPN balloon in patients with calcified coronary lesions. METHODS: This is an investigator-initiated, prospective, observational study. The primary outcome of the study was a procedural success. RESULTS: We studied 71 patients (133 lesions). Maximum lesions were located in LAD [46.6 %]. The OPN balloon was used for pre-dilatation alone in 28.6 % (Pre-stent OPN group), post-dilatation alone in 63.2 % of lesions (Post-stent OPN group), and in both situations in 8.3 % of lesions with procedural success in 98.5 % of patients. Further dilatation with different NC balloons was required in both groups (30 %). The median (IQR) OPN balloon diameter in the pre- and post-stent OPN group were 2.5 (2.5, 3.0) and 3.0 (3.0,3.0) mm (p = 0.001), respectively. The difference between the diameter of the stent and OPN balloon used in pre-stent OPN group was 0.5 (0.2, 0.5) mm while it was 0.0 (0.0,0.2) mm in the post-stent OPN group (p < 0.001). Eight complications and two deaths occured. Distal shaft rupture was also noticed. CONCLUSION: OPN balloon is safe, and effective in treating calcified coronary lesions. We propose to undersize the balloon by 0.5 mm for pre-dilatation followed by 0.25 mm larger NC balloon if needed. In the post-dilatation group, use a 1:1 size balloon in a non-tortuous straight segment. Use imaging especially when (1) the pressure taken more than the rated burst pressure, (2) an OPN balloon size is ≥3 mm (3) using 1:1 size OPN balloon in a tortuous segment.


Subject(s)
Angioplasty, Balloon, Coronary , Atherectomy, Coronary , Coronary Artery Disease , Vascular Calcification , Humans , Coronary Artery Disease/diagnostic imaging , Coronary Artery Disease/therapy , Prospective Studies , Atherectomy, Coronary/methods , Coronary Angiography , Treatment Outcome , Stents , Vascular Calcification/diagnostic imaging , Vascular Calcification/therapy
4.
ACS Appl Mater Interfaces ; 14(30): 34238-34246, 2022 Aug 03.
Article in English | MEDLINE | ID: mdl-35604015

ABSTRACT

Defect management strategies are vital for enhancing the performance of perovskite-based optoelectronic devices, such as perovskite-based light-emitting diodes (PeLEDs). As additives can fucntion both as acrystallization modifier and/or defect passivator, a thorough study on the roles of additives is essential, especially for blue emissive Pe-LEDs, where the emission is strictly controlled by the n-domain distribution of the Ruddlesden-Popper (RP, L2An-1PbnX3n+1, where L refers to a bulky cation, while A and X are monovalent cation, and halide anion, respectively) perovskite films. Of the various additives that are available, octyl phosphonic acid (OPA) is of immense interest because of its ability to bind with uncoordinated Pb2+ ( notorious for nonradiative recombination) and therefore passivates them. Here, with the help of various spectroscopic techniques, such as X-ray photon-spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), and photoluminescence quantum yield (PLQY) measurements, we demonstrate the capability of OPA to bind and passivate unpaired Pb2+ defect sites. Modification to crystallization promoting higher n-domain formation is also observed from steady-state and transient absorption (TA) measurements. With OPA treatment, both the PLQY and EQE of the corresponding PeLED showed improvements up to 53% and 3.7% at peak emission wavelength of 485 nm, respectively.

5.
Cardiol Res ; 13(2): 104-109, 2022 Apr.
Article in English | MEDLINE | ID: mdl-35465083

ABSTRACT

Background: Diffuse long coronary lesions are difficult to treat percutaneously. The aim of the present study was to assess the procedural safety and long-term efficacy of the ultra-long (48-mm) drug-eluting stent Xience Xpedition. Methods: This was an investigator-initiated, observational, all-comers study. A total of 92 patients with 93 lesions were enrolled in the study from October 2016 to October 2020. The primary outcome of the study was major adverse cardiac events (MACEs). Secondary outcomes were individual components of the primary outcome and procedural success. Results: The mean (standard deviation (SD)) age of the participants was 58.8 (10.8) years. More than half of the patients had ST-segment elevation myocardial infarction (STEMI) at presentation (55.4%). Ten patients were in cardiogenic shock (CGS; 10.8%). Most of the lesions were located in the left anterior descending artery (48.3%). American College of Cardiology/American Heart Association (ACC/AHA) type C was the most common lesion type amongst the intervened vessels (46.74%), with a mean syntax score (SD) of 16.99 (8.89). The mean stent diameter used was 2.77 mm (0.25). MACE was observed in 7.6% of patients studied at a median follow-up of 24 months. MACE was significantly lower in the population without CGS, occurring in only 2.4% of the patients; a significant difference in MACE was observed in patients with and without CGS (P < 0.001). Procedural success was obtained in 89.2% of total population; however, 96.3% of patients without CGS had procedural success. Conclusions: The deployment of the ultra-long 48-mm Xience Xpedition stent is feasible, safe, and effective; and it was associated with a good intermediate-term clinical outcome.

6.
Adv Mater ; 33(49): e2104381, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34632623

ABSTRACT

Perovskite light-emitting diodes (PeLEDs) have recently shown significant progress with external quantum efficiencies (EQEs) exceeding 20%. However, PeLEDs with pure-red (620-660 nm) light emission, an essential part for full-color displays, remain a great challenge. Herein, a general approach of spacer cation alloying is employed in Ruddlesden-Popper perovskites (RPPs) for efficient red PeLEDs with precisely tunable wavelengths. By simply tuning the alloying ratio of dual spacer cations, the thickness distribution of quantum wells in the RPP films can be precisely modulated without deteriorating their charge-transport ability and energy funneling processes. Consequently, efficient PeLEDs with tunable emissions between pure red (626 nm) and deep red (671 nm) are achieved with peak EQEs up to 11.5%, representing the highest values among RPP-based pure-red PeLEDs. This work opens a new route for color tuning, which will spur future developments of pure-red or even pure-blue PeLEDs with high performance.

7.
Pulm Circ ; 11(1): 2045894021992678, 2021.
Article in English | MEDLINE | ID: mdl-34104416

ABSTRACT

Acute pulmonary thromboembolism is associated with high mortality, similar to that of myocardial infarction and stroke. We studied the clinical presentation and management of pulmonary thromboembolism in the Indian population. An analysis of 140 patients who presented with acute pulmonary thromboembolism at a large volume center in India from June 2015 through December 2018 was performed. The mean age of our study population was 50 years with 59% being male. Comorbidities including deep vein thrombosis, diabetes mellitus, hypertension, and chronic obstructive pulmonary disease were present in 52.9%, 40%, 35.7% and 7.14% of patients, respectively. Out of 140 patients, 40 (28.6%) patients had massive pulmonary thromboembolism, 36 (25.7%) sub-massive pulmonary thromboembolism, and 64 (45.7%) had low-risk pulmonary thromboembolism. Overall, in-hospital mortality was 25.7%. Multivariate regression analysis found chronic kidney disease and pulmonary thromboembolism severity to be the only independent risk factors. Thrombolysis was performed in 62.5% of patients with a massive pulmonary thromboembolism and 63.9% of patients with a sub-massive pulmonary thromboembolism. In the massive pulmonary thromboembolism group, patients receiving thrombolytic therapy had lower mortality compared with patients who did not receive therapy (p=0.022), whereas this difference was not observed in patients in the sub-massive pulmonary thromboembolism group. We conclude that patients with acute pulmonary thromboembolism in India presented more than a decade earlier than our western counterparts, and it was associated with poor clinical outcomes. Thrombolysis was associated with significantly reduced in-hospital mortality in patients with massive pulmonary thromboembolism.

8.
Adv Mater ; 33(11): e2006233, 2021 Mar.
Article in English | MEDLINE | ID: mdl-33576093

ABSTRACT

Excitonic effects underpin the fascinating optoelectronic properties of 2D perovskites that are highly favorable for photovoltaics and light-emitting devices. Analogous to switching in transistors, manipulating these excitonic properties in 2D perovskites using coherent phonons could unlock new applications. Presently, a detailed understanding of this underlying mechanism remains modest. Herein, the origins of the carrier-phonon coupling in 2D perovskites using transient absorption (TA) spectroscopy are explicated. The exciton fine structure is modulated by coherent optical phonons dominated by the vibrational motion of the PbI6 octahedra via deformation potential. Originating from impulsive stimulated Raman scattering, these coherent vibrations manifest as oscillations in the TA spectrum comprising of the generation and detection processes of coherent phonons. This two-step process leads to a unique pump- and probe-energy dependence of the phonon modulation determined by the imaginary part of the refractive index and its derivative, respectively. The phonon frequency and lattice displacement of the inorganic octahedra are highly dependent on the organic cation. This study injects fresh insights into the exciton-phonon coupling of 2D perovskites relevant for emergent optoelectronics development.

9.
Int J Cardiol ; 330: 1-6, 2021 05 01.
Article in English | MEDLINE | ID: mdl-33600846

ABSTRACT

INTRODUCTION: Dual antiplatelet therapy (DAPT) remains the cornerstone of acute coronary syndrome (ACS) management, and ticagrelor is one of the commonly used second antiplatelet agents. There is some evidence to suggest that morphine may reduce the antiplatelet effect of ticagrelor. METHODS AND RESULTS: In a single-center, randomized controlled trial, we compared the effect of morphine and fentanyl on platelet aggregation (PA) among patients with ACS treated with ticagrelor. Platelet aggregation was studied by automated light transmittance aggregometry (LTA) at baseline, and at 2 h after ticagrelor loading. The primary outcome was the difference in the maximal inhibition of platelet aggregation [IPA(%)] between the groups at 2 h. Pain relief, and drug-related adverse events were secondary outcomes. Of 136 patients randomized, 70 received fentanyl and 66 received morphine. At baseline, the median (IQR) platelet aggregation [61.35% (54.6 to 70) Vs. 58.8% (52.7 to 72.9)] were comparable between the groups. There was no statistically significant difference between the fentanyl and the morphine groups in IPA at 2-h [85.88%(64.65-98.16) and 81.93%(44.2-98.03), p = 0.09]. However, morphine use was independently associated with a PA of >30% at 2 h (p < 0.009). There was no difference in adverse events. CONCLUSION: In patients with ACS, there was no significant difference between the use of fentanyl or morphine on the effect of ticagrelor on PA. (CTRI/2018/04/013423).


Subject(s)
Acute Coronary Syndrome , Percutaneous Coronary Intervention , Acute Coronary Syndrome/diagnosis , Acute Coronary Syndrome/drug therapy , Fentanyl , Humans , Morphine , Platelet Aggregation , Platelet Aggregation Inhibitors/pharmacology , Ticagrelor , Treatment Outcome
10.
Light Sci Appl ; 10(1): 2, 2021 Jan 01.
Article in English | MEDLINE | ID: mdl-33386385

ABSTRACT

The outstanding optoelectronic performance of lead halide perovskites lies in their exceptional carrier diffusion properties. As the perovskite material dimensionality is reduced to exploit the quantum confinement effects, the disruption to the perovskite lattice, often with insulating organic ligands, raises new questions on the charge diffusion properties. Herein, we report direct imaging of >1 µm exciton diffusion lengths in CH3NH3PbBr3 perovskite nanocrystal (PNC) films. Surprisingly, the resulting exciton mobilities in these PNC films can reach 10 ± 2 cm2 V-1 s-1, which is counterintuitively several times higher than the carrier mobility in 3D perovskite films. We show that this ultralong exciton diffusion originates from both efficient inter-NC exciton hopping (via Förster energy transfer) and the photon recycling process with a smaller yet significant contribution. Importantly, our study not only sheds new light on the highly debated origins of the excellent exciton diffusion in PNC films but also highlights the potential of PNCs for optoelectronic applications.

11.
Nano Lett ; 21(1): 405-413, 2021 Jan 13.
Article in English | MEDLINE | ID: mdl-33337888

ABSTRACT

Two-dimensional (2D) lead halide Ruddlesden-Popper perovskites (RPP) have recently emerged as a prospective material system for optoelectronic applications. Their self-assembled multi quantum-well structure gives rise to the novel interwell energy funnelling phenomenon, which is of broad interests for photovoltaics, light-emission applications, and emerging technologies (e.g., spintronics). Herein, we develop a realistic finite quantum-well superlattice model that corroborates the hypothesis of exciton delocalization across different quantum-wells in RPP. Such delocalization leads to a sub-50 fs coherent energy transfer between adjacent wells, with the efficiency depending on the RPP phase matching and the organic large cation barrier lengths. Our approach provides a coherent and comprehensive account for both steady-state and transient dynamical experimental results in RPPs. Importantly, these findings pave the way for a deeper understanding of these systems, as a cornerstone crucial for establishing material design rules to realize efficient RPP-based devices.

12.
Nat Commun ; 11(1): 2712, 2020 Jun 01.
Article in English | MEDLINE | ID: mdl-32483150

ABSTRACT

Amongst the many spectacular properties of hybrid lead halide perovskites, their defect tolerance is regarded as the key enabler for a spectrum of high-performance optoelectronic devices that propel perovskites to prominence. However, the plateauing efficiency enhancement of perovskite devices calls into question the extent of this defect tolerance in perovskite systems; an opportunity for perovskite nanocrystals to fill. Through optical spectroscopy and phenomenological modeling based on the Marcus theory of charge transfer, we uncover the detrimental effect of hot carriers trapping in methylammonium lead iodide and bromide nanocrystals. Higher excess energies induce faster carrier trapping rates, ascribed to interactions with shallow traps and ligands, turning these into potent defects. Passivating these traps with the introduction of phosphine oxide ligands can help mitigate hot carrier trapping. Importantly, our findings extend beyond photovoltaics and are relevant for low threshold lasers, light-emitting devices and multi-exciton generation devices.

13.
Sci Adv ; 6(8): eaax8821, 2020 Feb.
Article in English | MEDLINE | ID: mdl-32128397

ABSTRACT

In recent years, two-dimensional (2D) Ruddlesden-Popper perovskites have emerged as promising candidates for environmentally stable solar cells, highly efficient light-emitting diodes, and resistive memory devices. The remarkable existence of self-assembled quantum well (QW) structures in solution-processed 2D perovskites offers a diverse range of optoelectronic properties, which remain largely unexplored. Here, we experimentally observe ultrafast relaxation of free carriers in 20 ps due to the quantum confinement of free carriers in a self-assembled QW structures that form excitons. Furthermore, hybridizing the 2D perovskites with metamaterials on a rigid and a flexible substrate enables modulation of terahertz fields at 50-GHz modulating speed, which is the fastest for a solution-processed semiconductor-based photonic device. Hence, an exciton-based ultrafast response of 2D perovskites opens up large avenues for a wide range of scalable dynamic photonic devices with potential applications in flexible photonics, ultrafast wavefront control, and short-range wireless terahertz communications.

SELECTION OF CITATIONS
SEARCH DETAIL
...