Real-time phase-retrieval and wavefront sensing enabled by an artificial neural network.

In this manuscript we demonstrate a method to reconstruct the wavefront of focused beams from a measured diffraction pattern behind a diffracting mask in real-time. The phase problem is solved by means of a neural network, which is trained with simulated data and verified with experimental data. The neural network allows live reconstructions within a few milliseconds, which previously with iterative phase retrieval took several seconds, thus allowing the adjustment of complex systems and correction by adaptive optics in real time. The neural network additionally outperforms iterative phase retrieval with high noise diffraction patterns.

Dynamic white lighting to aid sleep and vision for persons living with dementia using off-the-shelf LED strips.

Alzheimer disease and related dementias affect 15-20% of elderly people, and 60-70% of these suffer from sleep disturbances. Studies suggest that lighting can improve sleep. The key challenge is how to deliver light effectively. We have designed a lighting system that adjusts spectrum and irradiance on a 24-hour timetable to provide spatially uniform, shadow-free white light with CRI>85 and up to 1000 Lux for day vision and amber light for night vision. To aid sleep, melanopic illuminance varies over 3 orders of magnitude to enable strong suppression of melatonin in the morning/early afternoon, moderate suppression in the evening, and no suppression at night.

Attosecond streaking phase retrieval with neural network.

A new method for retrieving the spectral phase of isolated attosecond X-ray pulses from streaking traces is explored. The neural network method shows the potential for nearly instantaneous attosecond streaking phase retrieval, without use of the central momentum approximation. A neural network is trained with computer generated data that contain statistical noise and shown to correctly retrieve the phase of both computer generated and experimental attosecond streaking traces.

Double optical gating for generating high flux isolated attosecond pulses in the soft X-ray regime.

Double optical gating (DOG) technique was implemented with a two-cycle, 1.7 µm driving field to generate isolated attosecond pulses in the 100-250 eV spectrum range. The strong ellipticity dependency of the high harmonics from the 1.7 µm driving field makes polarization based gating method very efficient. When a second harmonic (SH) field is introduced, complete gating can be achieved with less ionization from the leading edge of the driving field, which yields supercontinua with a pulse energy of 0.3 nJ. We perform an attosecond streaking measurement to confirm the generation of isolated attosecond pulses.

MEH-PPV photophysics: insights from the influence of a nearby 2D quencher.

The effect of 2D quenching on single chain photophysics was investigated by spin coating 13 nm thick films of polystyrene lightly doped with MEH-PPV onto CVD grown graphene and observing the changes in several photoluminescent (PL) observables. With 99% of the PL quenched, we found a 60% drop in the PL lifetime, along with a significant blue-shift of the PL emission due to the preferential quenching of emission at longer wavelengths. During photo-bleaching, the blue spectral shift observed for isolated polymers was eliminated in the presence of the quencher up until 70% of the polymer was photo-bleached. Results were interpreted using a static disorder induced conjugation length distribution model. The quencher, by opening up a new non-radiative decay channel, ensures that excitons do not have sufficient time to migrate to nearby lower energy chromophores. The reduction of energy transfer into the lowest-energy chromophores thus reduces their rate of photo-bleaching. Finally, the difference between the quenched and non-quenched spectra allows the rate of energy transfer along the polymer backbone to be estimated at ∼2 ns-1.

Clinical and procedural outcomes with the SAPIEN 3 versus the SAPIEN XT prosthetic valves in transcatheter aortic valve replacement: A systematic review and meta-analysis.

OBJECTIVES: The SAPIEN 3 valve (S3V) was designed to overcome the shortcomings of its predecessor, the SAPIEN XT (SXT) valve. We conducted a meta-analysis to compare their clinical outcomes and procedural characteristics. METHODS: PUBMED, EMBASE, and Cochrane CENTRAL were searched by two independent reviewers. The clinical outcomes of interest were paravalvular leakage (PVL), major vascular complications (MVC), bleeding, acute kidney injury (AKI), device success, need for post dilation all-cause mortality and procedural details. RESULTS: Fifteen observational cohort studies were included in the analysis involving a total of 4,496 patients. Of these, 1,700 were S3V recipients and 2,796 were SXT recipients. The S3V group showed fewer complications compared to the SXT group with respect to PVL (5.58% vs. 19.35%, OR: 0.27, P: 0.000), MVC (4.07% vs. 9.13%, OR: 0.44, P: 0.002), bleeding (6.40% vs. 12.03%, OR: 0.50, P: 0.003), 30-day mortality (3.29% vs. 5.68%, OR: 0.51, P: 0.000), and stroke (1.48% vs. 2.86%, OR: 0.49, P: 0.014). Device success was higher in the S3V (98.18% vs. 93.76%, OR: 3.14, P: 0.000). Cardiovascular mortality, myocardial infarction, AKI and post-dilatation were not significantly different. Permanent pacemaker implantation (PPI) was higher in S3V recipients (13.29% vs. 9.23%, OR: 1.58, P: 0.000). Procedure time was shorter for the S3V (71.94 vs. 86.85, P: 0.016) and used less contrast volume (129.36 vs. 161.18, P: 0.049). CONCLUSIONS: Patients receiving the S3V had lower risk of PVL, MVC, bleeding, mortality, and stroke. PPI was somewhat higher in the S3V group. S3V implantation was faster and used less contrast.

Optimizing hemodynamics of transcatheter aortic valve-in-valve implantation in 19-mm surgical aortic prostheses.

OBJECTIVE: To demonstrate the feasibility of achieving good hemodynamic results with valve-in-valve transcatheter aortic valve replacement (ViV TAVR) for degenerated 19 mm surgical bioprosthetic valves. BACKGROUND: Considerable controversy exists regarding ViV TAVR within 19mm surgical prostheses due to concerns of elevated valve gradients and mortality. METHODS: Among all patient undergoing ViV TAVR between 7/2016 and 4/2017 for symptomatic severe bioprosthetic aortic stenosis (AS), five had a 19 mm surgical valve in place and were included in this publication. None of the patients had patient-prosthesis mismatch. Aggressive post-dilation was performed in four out of five cases using a special technique we describe below. RESULTS: In all cases, mean aortic valve (AV) gradients significantly improved post-ViV TAVR, particularly after post-dilation. Interestingly, high pressure post-dilation of the ViV resulted in an increase in the diameter of surgical valve stent frame dimensions in nearly all patients who underwent post-dilation. CONCLUSIONS: Good hemodynamic outcome is possible with aggressive post-dilation in patients with 19 mm failed surgical bioprostheses. High-risk patients with 19 mm failed surgical prostheses who do not otherwise have viable surgical options should be considered for ViV TAVR.

Three, six, or twelve months of dual antiplatelet therapy after DES implantation in patients with or without acute coronary syndromes: an individual patient data pairwise and network meta-analysis of six randomized trials and 11 473 patients.

Aim: We sought to determine whether the optimal dual antiplatelet therapy (DAPT) duration after drug-eluting stent (DES) placement varies according to clinical presentation. Methods and Results: We performed an individual patient data pairwise and network meta-analysis comparing short-term (≤6-months) versus long-term (1-year) DAPT as well as 3-month vs. 6-month vs 1-year DAPT. The primary study outcome was the 1-year composite risk of myocardial infarction (MI) or definite/probable stent thrombosis (ST). Six trials were included in which DAPT after DES consisted of aspirin and clopidogrel. Among 11 473 randomized patients 6714 (58.5%) had stable CAD and 4758 (41.5%) presented with acute coronary syndrome (ACS), the majority of whom (67.0%) had unstable angina. In ACS patients, ≤6-month DAPT was associated with non-significantly higher 1-year rates of MI or ST compared with 1-year DAPT (Hazard Ratio (HR) 1.48, 95% Confidence interval (CI) 0.98-2.22; P = 0.059), whereas in stable patients rates of MI and ST were similar between the two DAPT strategies (HR 0.93, 95%CI 0.65-1.35; P = 0.71; Pinteraction = 0.09). By network meta-analysis, 3-month DAPT, but not 6-month DAPT, was associated with higher rates of MI or ST in ACS, whereas no significant differences were apparent in stable patients. Short DAPT was associated with lower rates of major bleeding compared with 1-year DAPT, irrespective of clinical presentation. All-cause mortality was not significantly different with short vs. long DAPT in both patients with stable CAD and ACS. Conclusions: Optimal DAPT duration after DES differs according to clinical presentation. In the present meta-analysis, despite the fact that most enrolled ACS patients were relatively low risk, 3-month DAPT was associated with increased ischaemic risk, whereas 3-month DAPT appeared safe in stable CAD. Prolonged DAPT increases bleeding regardless of clinical presentation. Further study is required to identify the optimal duration of DAPT after DES in individual patients based on their relative ischaemic and bleeding risks.

On the potential of solid state LED strips utilizing an organic color converter for non-line of sight visible light communication.

LED strip lighting can provide high quality uniform shadow-free diffuse lighting at low cost as numerous emission sources are controlled by a single transformer. Organic LEDs offer the additional advantages of UV free emission and, for visible light communication, picosecond fluorescent lifetimes allowing the whole visible spectrum to be used without filters. Using parameters determined experimentally for solid-state LED strip lighting and fluorescent lifetimes typical of organic phosphors as the input for a Monte Carlo based ray-tracing simulation, we evaluate the potential bandwidths obtainable for indoor communication. Our work suggests that raw data transfer rates of 4 to 10 Mbps are obtainable in a standard 5m by 5m by 3m room compatible with Internet of Things (IoT) applications.

Local oxidation and reduction of graphene.

Micrometer sized oxidation patterns were created in chemical vapor deposition grown graphene through scanning probe lithography (SPL) and then subsequently reduced by irradiation using a focused x-ray beam. Throughout the process, the films were characterized by lateral force microscopy, micro-Raman and micro-x-ray photoelectron spectroscopy. Firstly, the density of grain boundaries was found to be crucial in determining the maximum possible oxygen coverage with SPL. Secondly, the dominant factor in SPL oxidation was found to be the bias voltage. At low voltages, only structural defects are formed on grain boundaries. Above a distinct threshold voltage, oxygen coverage increased rapidly, with the duration of applied voltage affecting the final oxygen coverage. Finally, we found that, independent of initial conditions, types of defects or the amount of SPL oxidation, the same set of coupled rate equations describes the reduction dynamics with the limiting reduction step being C-C â†’ C=C.

Early clinical and echocardiographic outcomes after SAPIEN 3 transcatheter aortic valve replacement in inoperable, high-risk and intermediate-risk patients with aortic stenosis.

AIMS: Based on randomized trials using first-generation devices, transcatheter aortic valve replacement (TAVR) is well established in the treatment of high-risk (HR) patients with severe aortic stenosis (AS). To date, there is a paucity of adjudicated, prospective data evaluating outcomes with newer generation devices and in lower risk patients. We report early outcomes of a large, multicentre registry of inoperable, HR, and intermediate-risk (IR) patients undergoing treatment with the next-generation SAPIEN 3 transcatheter heart valve (THV). METHODS AND RESULTS: Patients with severe, symptomatic AS (583 high surgical risk or inoperable and 1078 IR) were enrolled in a multicentre, non-randomized registry at 57 sites in the USA and Canada. All patients received TAVR with the SAPIEN 3 system via transfemoral (n = 1443, 86.9%) and transapical or transaortic (n = 218, 13.1%) access routes. The rate of 30-day all-cause mortality was 2.2% in HR/inoperable patients [mean Society of Thoracic Surgeons (STS) score 8.7%] and 1.1% in IR patients (mean STS score 5.3%); cardiovascular mortality was 1.4 and 0.9%, respectively. In HR/inoperable patients, the 30-day rate of major/disabling stroke was 0.9%, major bleeding 14.0%, major vascular complications 5.1%, and requirement for permanent pacemaker 13.3%. In IR patients, the 30-day rate of major/disabling stroke was 1.0%, major bleeding 10.6%, major vascular complications 6.1%, and requirement for permanent pacemaker 10.1%. Mean overall Kansas City Cardiomyopathy Questionnaire score increased from 47.8 to 67.8 (HR/inoperable, P < 0.0001) and 54.7 to 74.0 (IR, P < 0.0001). Overall, paravalvular regurgitation at 30 days was none/trace in 55.9% of patients, mild in 40.7%, moderate in 3.4%, and severe in 0.0%. Mean gradients among patients with paired baseline and 30-day or discharge echocardiograms decreased from 45.8 mmHg at baseline to 11.4 mmHg at 30 days, while aortic valve area increased from 0.69 to 1.67 cm(2). CONCLUSIONS: The SAPIEN 3 THV system was associated with low rates of 30-day mortality and major/disabling stroke as well as low rates of moderate or severe paravalvular regurgitation. TRIAL REGISTRATION: ClinicalTrials.gov #NCT01314313.

Controlling photoluminescent emission from polymer membranes through the creation of local deformation zones.

Understanding and optimizing light propagation and extraction in light-emitting systems, such as fluorescent chemical sensors, is important for the production of more efficient sensors. We apply Monte Carlo ray tracing to model the effects of one-dimensional perturbations of film thickness on the luminescent emission (spatial, directional, spectral) of a freestanding transparent polymer film embedded with luminescent chromophores. Such modification not only enhances light extraction but also allows its location and direction to be controlled. Optimization of the deformation geometry allows for a 3.6-fold increase in intensity for a far-field detector.

Intra-aortic balloon counterpulsation in contemporary practice - where are we?

The intra-aortic balloon pump (IABP) remains the most widely used form of mechanical circulatory support in current clinical practice. This article will review the current evidence to guide IABP use, focussing on large registry and prospective, randomised data, and seek to establish appropriate roles for the IABP in contemporary practice. Despite a paucity of clinical evidence, the IABP remains a useful clinical tool in selected settings, although its routine, up-front use in relatively unselected MI populations is not supported by data. Although current evidence no longer supports routine use in certain high-risk groups, further studies of appropriately selected high-risk patients may yet demonstrate benefit in patients with moderate-severe degrees of shock.

Impact of the COVID-19 Pandemic on Global TAVR Activity: The COVID-TAVI Study.

BACKGROUND: The COVID-19 pandemic adversely affected health care systems. Patients in need of transcatheter aortic valve replacement (TAVR) are especially susceptible to treatment delays. OBJECTIVES: This study sought to evaluate the impact of the COVID-19 pandemic on global TAVR activity. METHODS: This international registry reported monthly TAVR case volume in participating institutions prior to and during the COVID-19 pandemic (January 2018 to December 2021). Hospital-level information on public vs private, urban vs rural, and TAVR volume was collected, as was country-level information on socioeconomic status, COVID-19 incidence, and governmental public health responses. RESULTS: We included 130 centers from 61 countries, including 65,980 TAVR procedures. The first and second pandemic waves were associated with a significant reduction of 15% (P < 0.001) and 7% (P < 0.001) in monthly TAVR case volume, respectively, compared with the prepandemic period. The third pandemic wave was not associated with reduced TAVR activity. A greater reduction in TAVR activity was observed in Africa (-52%; P = 0.001), Central-South America (-33%; P < 0.001), and Asia (-29%; P < 0.001). Private hospitals (P = 0.005), urban areas (P = 0.011), low-volume centers (P = 0.002), countries with lower development (P < 0.001) and economic status (P < 0.001), higher COVID-19 incidence (P < 0.001), and more stringent public health restrictions (P < 0.001) experienced a greater reduction in TAVR activity. CONCLUSIONS: TAVR procedural volume declined substantially during the first and second waves of the COVID-19 pandemic, especially in Africa, Central-South America, and Asia. National socioeconomic status, COVID-19 incidence, and public health responses were associated with treatment delays. This information should inform public health policy in case of future global health crises.

Validation of colorectal cancer surgery data from administrative data sources.

BACKGROUND: Surgery is the primary treatment for colorectal cancer for both curative and palliative intent. Availability of high quality surgery data is essential for assessing many aspects of the quality of colorectal cancer care. The objective of this study was to determine the quality of different administrative data sources in identifying surgery for colorectal cancer with respect to completeness and accuracy. METHODS: All residents in Alberta, Canada who were diagnosed with invasive colorectal cancer in years 2000-2005 were identified from the Alberta Cancer Registry and included in the study. Surgery data for these patients were obtained from the Cancer Registry (which collects the date of surgery for which the primary tumor was removed) and compared to surgery data obtained from two different administrative data sources: Physician Billing and Hospital Inpatient data. Sensitivity, specificity, positive predictive value, negative predictive value and observed agreement were calculated compared to the Cancer Registry data. RESULTS: The Physician Billing data alone or combined with Hospital Inpatient data demonstrated equally high sensitivity (97% for both) and observed agreement with the Cancer Registry data (93% for both) for identifying surgeries. The Hospital Inpatient data, however, had the highest specificity (80%). The positive predictive value varied by disease stage and across data sources for stage IV (99% for stages I-III and 83-89% for stage IV), the specificity is better for colon cancer surgeries (72-85%) than for rectal cancer surgeries (60-73%); validation measures did not vary over time. CONCLUSION: Physician Billing data identify the colorectal cancer surgery more completely than Hospital Inpatient data although both sources have a high level of completeness.

Attosecond pulse retrieval from noisy streaking traces with conditional variational generative network.

Accurate characterization of an attosecond pulse from streaking trace is an indispensable step in studying the ultrafast electron dynamics on the attosecond scale. Conventional attosecond pulse retrieval methods face two major challenges: the ability to incorporate a complete physics model of the streaking process, and the ability to model the uncertainty of pulse reconstruction in the presence of noise. Here we propose a pulse retrieval method based on conditional variational generative network (CVGN) that can address both demands. Instead of learning the inverse mapping from a streaking trace to a pulse profile, the CVGN models the distribution of the pulse profile conditioned on a given streaking trace measurement, and is thus capable of assessing the uncertainty of the retrieved pulses. This capability is highly desirable for low-photon level measurement, which is typical in attosecond streaking experiments in the water window X-ray range. In addition, the proposed scheme incorporates a refined physics model that considers the Coulomb-laser coupling and photoelectron angular distribution in streaking trace generation. CVGN pulse retrievals under various simulated noise levels and experimental measurement have been demonstrated. The results showed high pulse reconstruction consistency for streaking traces when peak signal-to-noise ratio (SNR) exceeds 6, which could serve as a reference for future learning-based attosecond pulse retrieval.

Atrial fibrillation in acute coronary syndrome: patient characteristics and appropriate utilisation of anti-thrombotic therapy in New Zealand (ANZACS-QI 39).

BACKGROUND: Concomitant atrial fibrillation (AF) and acute coronary syndrome (ACS) present the difficult therapeutic dilemma of balancing bleeding, cardio-embolic and coronary thrombotic risks with appropriate combinations of antithrombotic medications. We aim to evaluate current New Zealand practice by identifying the incidence of AF in ACS; describe the population characteristics; and assess our antithrombotic management. METHODS: Consecutive patients ≥18y presenting with ACS who had coronary angiography (2017-2018) were identified from the All New Zealand ACS Quality Improvement (ANZACS-QI) registry. The cohort was divided into three groups: 1) patients with pre-existing AF; 2) new-onset AF; and 3) no AF. Antithrombotic regimens included dual antiplatelet therapy (DAPT), dual antithrombotic therapy (DAT-single antiplatelet plus an oral anticoagulant (OAC)) and triple antithrombotic therapy (TAT). RESULTS: There were 9,489 patients, 9.6% with pre-existing AF, 4.4% new AF and 86% without AF. Both AF groups were older (median 74 vs 71 vs 65y, p=0.001), had poorer renal function, were more likely to present with heart failure (16% vs 19% vs 8%, p=0.001) and have left ventricular ejection fraction <40% (22% vs 28% vs 13%, p<0.001). They received less percutaneous coronary intervention (PCI) (53% vs 59% vs 70%, p=0.001). In the cohort, 25 different combinations of antithrombotic agents were utilised. Ninety-six percent of patients with any AF had a CHA2DS2VASC stroke risk score of ≥2, of whom 48% did not receive OAC. Twenty-four percent received TAT and 19% DAT. OAC use increased slightly with increasing stroke risk but were independent of CRUSADE bleeding risk. Of patients with AF treated with PCI, 53% received DAPT, 11% DAT and 35% TAT. 51% of those at high stroke risk were discharged on DAPT only. In contrast, 19% at low stroke risk received TAT. CONCLUSION: In New Zealand, one in seven patients presenting with ACS have AF, a third being new-onset AF. Antithrombotic management is inconsistent, with underutilisation of anticoagulants, particularly the DAT regimen, and is inadequately informed by stroke and bleeding risk scores.

Large Left Ventricular Outflow Tract Pseudoaneurysm Closed Percutaneously From a Novel Apical Approach.

An incidental finding of a large left ventricular outflow tract pseudoaneurysm in a 74-year-old man, with high surgical risk, was managed with a novel, fully percutaneous, left ventricular apical approach. The pseudoaneurysm defect and the apical puncture site were successfully closed with Amplatzer septal occluders with successful positioning, as demonstrated on cardiac computed tomography at 6 weeks follow-up. (Level of Difficulty: Intermediate.).