Impact of device resistances in the performance of graphene-based terahertz photodetectors

In recent years, graphene field-effect-transistors (GFETs) have demonstrated an outstanding potential for terahertz (THz) photodetection due to their fast response and high-sensitivity. Such features are essential to enable emerging THz applications, including 6G wireless communications, quantum information, bioimaging and security. However, the overall performance of these photodetectors may be utterly compromised by the impact of internal resistances presented in the device, so-called access or parasitic resistances. In this work, we provide a detailed study of the influence of internal device resistances in the photoresponse of high-mobility dual-gate GFET detectors. Such dual-gate architectures allow us to fine tune (decrease) the internal resistance of the device by an order of magnitude and consequently demonstrate an improved responsivity and noise-equivalent-power values of the photodetector, respectively. Our results can be well understood by a series resistance model, as shown by the excellent agreement found between the experimental data and theoretical calculations. These findings are therefore relevant to understand and improve the overall performance of existing high-mobility graphene photodetectors.

Electrical noise spectroscopy of magnons in a quantum Hall ferromagnet

Collective spin-wave excitations, magnons, are promising quasi-particles for next-generation spintronics devices, including platforms for information transfer. In a quantum Hall ferromagnets, detection of these charge-neutral excitations relies on the conversion of magnons into electrical signals in the form of excess electrons and holes, but if the excess electron and holes are equal, detecting an electrical signal is challenging. In this work, we overcome this shortcoming by measuring the electrical noise generated by magnons. We use the symmetry-broken quantum Hall ferromagnet of the zeroth Landau level in graphene to launch magnons. Absorption of these magnons creates excess noise above the Zeeman energy and remains finite even when the average electrical signal is zero. Moreover, we formulate a theoretical model in which the noise is produced by equilibration between edge channels and propagating magnons. Our model also allows us to pinpoint the regime of ballistic magnon transport in our device.

Distance Dependence of the Energy Transfer Mechanism in WS_{2}-Graphene Heterostructures

We report on the mechanism of energy transfer in Van der Waals heterostructures of the two-dimensional semiconductor WS_{2} and graphene with varying interlayer distances, achieved through spacer layers of hexagonal boron nitride (h-BN). We record photoluminescence and reflection spectra at interlayer distances between 0.5 and 5.8 nm (0-16  h-BN layers). We find that the energy transfer is dominated by states outside the light cone, indicative of a Förster transfer process, with an additional contribution from a Dexter process at 0.5 nm interlayer distance. We find that the measured dependence of the luminescence intensity on interlayer distances above 1 nm can be quantitatively described using recently reported values of the Förster transfer rates of thermalized charge carriers. At smaller interlayer distances, the experimentally observed transfer rates exceed the predictions and, furthermore, depend on excess energy as well as on excitation density. Since the transfer probability of the Förster mechanism depends on the momentum of electron-hole pairs, we conclude that, at these distances, the transfer is driven by nonrelaxed charge carrier distributions.

One-dimensional proximity superconductivity in the quantum Hall regime

Extensive efforts have been undertaken to combine superconductivity and the quantum Hall effect so that Cooper-pair transport between superconducting electrodes in Josephson junctions is mediated by one-dimensional edge states1-6. This interest has been motivated by prospects of finding new physics, including topologically protected quasiparticles7-9, but also extends into metrology and device applications10-13. So far it has proven challenging to achieve detectable supercurrents through quantum Hall conductors2,3,6. Here we show that domain walls in minimally twisted bilayer graphene14-18 support exceptionally robust proximity superconductivity in the quantum Hall regime, allowing Josephson junctions to operate in fields close to the upper critical field of superconducting electrodes. The critical current is found to be non-oscillatory and practically unchanging over the entire range of quantizing fields, with its value being limited by the quantum conductance of ballistic, strictly one-dimensional, electronic channels residing within the domain walls. The system described is unique in its ability to support Andreev bound states at quantizing fields and offers many interesting directions for further exploration.

Relationship of Mild to Moderate Impairment of Left Ventricular Ejection Fraction With Fatal Ventricular Arrhythmic Events in Cardiac Sarcoidosis

BACKGROUND

Current guidelines recommend placing an implantable cardiac defibrillator for patients with cardiac sarcoidosis and a severely impaired left ventricular ejection fraction (LVEF) of ≤35%. In this study, we determined the association between mild or moderate LVEF impairment and fatal ventricular arrhythmic event (FVAE).

METHODS AND RESULTS

We retrospectively analyzed 401 patients with cardiac sarcoidosis without sustained ventricular arrhythmia at diagnosis. The primary end point was an FVAE, defined as the combined endpoint of documented ventricular tachycardia or ventricular fibrillation and sudden cardiac death. Two cutoff points for LVEF were used: a sex-specific lower threshold of normal range of LVEF (52% for men and 54% for women) and an LVEF of 35%, which is used in the current guidelines. During a median follow-up of 3.2 years, 58 FVAEs were observed, and the 5- and 10-year estimated incidences of FVAEs were 16.8% and 23.0%, respectively. All patients were classified into 3 groups according to LVEF: impaired LVEF group, mild to moderate impairment of LVEF group, and maintained LVEF group. Multivariable competing risk analysis showed that both the impaired LVEF group (hazard ratio [HR], 3.24 [95% CI, 1.49-7.04]) and the mild to moderate impairment of LVEF group (HR, 2.16 [95% CI, 1.04-4.46]) were associated with a higher incidence of FVAEs than the maintained LVEF group after adjustment for covariates.

CONCLUSIONS

Patients with cardiac sarcoidosis are at a high risk of FVAEs, regardless of documented ventricular arrhythmia at the time of diagnosis. In patients with cardiac sarcoidosis, mild to moderate impairment of LVEF is associated with FVAEs.

Electric-Field-Tunable Edge Transport in Bernal-Stacked Trilayer Graphene

This Letter presents a nonlocal study on the electric-field-tunable edge transport in h-BN-encapsulated dual-gated Bernal-stacked (ABA) trilayer graphene across various displacement fields (D) and temperatures (T). Our measurements revealed that the nonlocal resistance (R_{NL}) surpassed the expected classical Ohmic contribution by a factor of at least 2 orders of magnitude. Through scaling analysis, we found that the nonlocal resistance scales linearly with the local resistance (R_{L}) only when the D exceeds a critical value of ∼0.2  V/nm. Additionally, we observed that the scaling exponent remains constant at unity for temperatures below the bulk-band gap energy threshold (T<25  K). Further, the value of R_{NL} decreases in a linear fashion as the channel length (L) increases. These experimental findings provide evidence for edge-mediated charge transport in ABA trilayer graphene under the influence of a finite displacement field. Furthermore, our theoretical calculations support these results by demonstrating the emergence of dispersive edge modes within the bulk-band gap energy range when a sufficient displacement field is applied.

Terahertz Detection by Asymmetric Dual Grating Gate Bilayer Graphene FETs with Integrated Bowtie Antenna

An asymmetric dual-grating gate bilayer graphene-based field effect transistor (ADGG-GFET) with an integrated bowtie antenna was fabricated and its response as a Terahertz (THz) detector was experimentally investigated. The device was cooled down to 4.5 K, and excited at different frequencies (0.15, 0.3 and 0.6 THz) using a THz solid-state source. The integration of the bowtie antenna allowed to obtain a substantial increase in the photocurrent response (up to 8 nA) of the device at the three studied frequencies as compared to similar transistors lacking the integrated antenna (1 nA). The photocurrent increase was observed for all the studied values of the bias voltage applied to both the top and back gates. Besides the action of the antenna that helps the coupling of THz radiation to the transistor channel, the observed enhancement by nearly one order of magnitude of the photoresponse is also related to the modulation of the hole and electron concentration profiles inside the transistor channel by the bias voltages imposed to the top and back gates. The creation of local n and p regions leads to the formation of homojuctions (np, pn or pp+) along the channel that strongly affects the overall photoresponse of the detector. Additionally, the bias of both back and top gates could induce an opening of the gap of the bilayer graphene channel that would also contribute to the photocurrent.

Interaction-Induced ac Stark Shift of Exciton-Polaron Resonances

Laser-induced shift of atomic states due to the ac Stark effect has played a central role in cold-atom physics and facilitated their emergence as analog quantum simulators. Here, we explore this phenomenon in an atomically thin layer of semiconductor MoSe_{2}, which we embedded in a heterostructure enabling charge tunability. Shining an intense pump laser with a small detuning from the material resonances, we generate a large population of virtual collective excitations and achieve a regime where interactions with this background population are the leading contribution to the ac Stark shift. Using this technique we study how itinerant charges modify-and dramatically enhance-the interactions between optical excitations. In particular, our experiments show that the interaction between attractive polarons could be more than an order of magnitude stronger than those between bare excitons.

Characteristics and incidence of cardiac events across spectrum of age in cardiac sarcoidosis

Background

Clinical characteristics and the risk of cardiovascular events in patients with cardiac sarcoidosis (CS) according to the age of initial diagnosis are unclear.

Methods

This study is a sub-analysis of the ILLUMINATE-CS registry, which is a retrospective, multicenter registry that enrolled patients with CS between 2001 and 2017. Patients were divided into three groups according to the tertile of age at the time of initial diagnosis of CS. The study compared the clinical background at the time of CS diagnosis and the incidence rate of cardiac events across age categories.

Results

A total of 511 patients were analyzed in this study. In baseline, older patients were more likely to be female. History of hypertension, heart failure admission, and atrioventricular block were more common in patients with older age. There was no significant difference in the history of ventricular arrhythmias and left ventricular ejection fraction among all age groups. During a median follow-up period of 3.2 [IQR: 1.7-4.2] years, 35 deaths, 56 heart failure hospitalization, and 98 fatal ventricular arrhythmias was observed. The incidence rate of all-cause death and heart failure hospitalization was significantly higher in patients with older age (p < 0.001), while there was no significant difference in the incidence rate of ventricular arrhythmia among age groups (p = 0.74).

Conclusions

In patients with CS, the risk of all-cause death and heart failure hospitalization was higher in older patients compared with other age groups; however, the risk of ventricular arrhythmia was comparable across all age groups.

Nitrogen concentration control during diamond growth for NV- centre formation

Negatively charged nitrogen-vacancy (NV-) centres formed in diamond crystals are point defects that have potential applications in various quantum devices such as highly sensitive magnetic sensors. To improve the sensitivity of magnetic sensors using NV- centres, it is essential to precisely control the nitrogen concentration in the crystals. In this paper, we demonstrated that nitrogen concentration in diamond can be controlled with high precision for the following two representative growth methods. One is the high-pressure/high-temperature (HPHT) synthesis method and the other is the chemical vapour deposition (CVD) method. The nitrogen concentration of HPHT-grown diamond decreased semi-logarithmically with increasing contents of titanium or aluminium as nitrogen getter materials. The nitrogen concentration of CVD-grown diamond increased linearly with increasing the flow rate ratio of nitrogen to carbon. NV- centres were formed by controlling the total fluence of electron beams so that approximately 20% of the nitrogen became NV- centres. The coherence time of electron spin of NV- centres obtained by the Hahn-echo pulse sequence T2 of these diamond crystals was inversely proportional to the nitrogen concentration. A comparison of T2 of the NV- centres for HPHT-synthesized and CVD-grown diamonds showed no significant difference between them. This article is part of the Theo Murphy meeting issue 'Diamond for quantum applications'.

Clinical characteristics and prognosis of patients with isolated cardiac sarcoidosis: Insights from the ILLUMINATE-CS study

AIM

Data on the clinical features and prognosis of patients with isolated cardiac sarcoidosis (iCS) are limited. This study evaluated the clinical characteristics and prognostic impact of iCS.

METHODS AND RESULTS

This was a secondary analysis of the ILLUMINATE-CS study, a multicentre, retrospective registry investigating the clinical characteristics and prognosis of cardiac sarcoidosis. iCS was diagnosed according to the 2016 Japanese Circulation Society (JCS) guidelines. Clinical characteristics and prognosis were compared between patients with iCS and systemic cardiac sarcoidosis (sCS). The primary outcome was a combined endpoint of all-cause death, hospitalization for heart failure, or fatal ventricular arrhythmia events. Among 475 patients with CS (mean age, 62.0 ± 10.9 years; female ratio, 59%) diagnosed by the JCS guidelines, 119 (25.1%) were diagnosed with iCS. Patients with iCS had a higher prevalence of a history of atrial fibrillation or hospitalization for heart failure, or lower left ventricular ejection fraction than those with sCS. During a median follow-up of 42.3 (interquartile range, 22.8-72.5) months, 141 primary outcomes (29.7%) occurred. Cox proportional hazard analysis revealed that iCS was a significant risk factor for the primary outcome in the unadjusted model (hazard ratio [HR] 1.62; 95% confidence interval [CI] 1.12-2.34; p = 0.011). However, this association was not retained after adjustment for other covariates (adjusted HR 1.27; 95% CI 0.86-1.88; p = 0.226).

CONCLUSIONS

Patients with iCS had more impaired cardiovascular function at the time of diagnosis than those with sCS. However, iCS was not independently associated with poor prognosis after adjustment for prognostic factors.

Band structure sensitive photoresponse in twisted bilayer graphene proximitized with WSe2

The ability to tune the twist angle between different layers of two-dimensional (2D) materials has enabled the creation of electronic flat bands artificially, leading to exotic quantum phases. When a twisted blilayer of graphene (tBLG) is placed at the van der Waals proximity to a semiconducting layer of transition metal dichalcogenide (TMDC), such as WSe2, the emergent phases in the tBLG can fundamentally modify the functionality of such heterostructures. Here we have performed photoresponse measurements in few-layer-WSe2/tBLG heterostructure, where the mis-orientation angle of the tBLG layer was chosen to lie close to the magic angle of 1.1°. Our experiments show that the photoresponse is extremely sensitive to the band structure of tBLG and gets strongly suppressed when the Fermi energy was placed within the low-energy moiré bands. Photoresponse could however be recovered when Fermi energy exceeded the moiré band edge where it was dominated by the photogating effect due to transfer of charge between the tBLG and the WSe2 layers. Our observations suggest the possibility of the screening effects from moiré flat bands that strongly affect the charge transfer process at the WSe2/tBLG interface, which is further supported by time-resolved photo-resistance measurements.

Coherent charge oscillations in a bilayer graphene double quantum dot

The coherent dynamics of a quantum mechanical two-level system passing through an anti-crossing of two energy levels can give rise to Landau-Zener-Stückelberg-Majorana (LZSM) interference. LZSM interference spectroscopy has proven to be a fruitful tool to investigate charge noise and charge decoherence in semiconductor quantum dots (QDs). Recently, bilayer graphene has developed as a promising platform to host highly tunable QDs potentially useful for hosting spin and valley qubits. So far, in this system no coherent oscillations have been observed and little is known about charge noise in this material. Here, we report coherent charge oscillations and [Formula: see text] charge decoherence times in a bilayer graphene double QD. The charge decoherence times are measured independently using LZSM interference and photon assisted tunneling. Both techniques yield [Formula: see text] average values in the range of 400-500 ps. The observation of charge coherence allows to study the origin and spectral distribution of charge noise in future experiments.

Excited state spectroscopy and spin splitting in single layer MoS2 quantum dots

Semiconducting transition metal dichalcogenides (TMDCs) are very promising materials for quantum dots and spin-qubit implementation. Reliable operation of spin qubits requires the knowledge of the Landé g-factor, which can be measured by exploiting the discrete energy spectrum on a quantum dot. However, the quantum dots realized in TMDCs are yet to reach the required control and quality for reliable measurement of excited state spectroscopy and the g-factor, particularly in atomically thin layers. Quantum dot sizes reported in TMDCs so far are not small enough to observe discrete energy levels on them. Here, we report on electron transport through discrete energy levels of quantum dots in a single layer MoS2 isolated from its environment using a dual gate geometry. The quantum dot energy levels are separated by a few (5-6) meV such that the ground state and the first excited state transitions are clearly visible, thanks to the low contact resistance of ∼700 Ω and relatively low gate voltages. This well-resolved energy separation allowed us to accurately measure the ground state g-factor of ∼5 in MoS2 quantum dots. We observed a spin-filling sequence in our quantum dots under a perpendicular magnetic field. Such a system offers an excellent testbed to measure the key parameters for evaluation and implementation of spin-valley qubits in TMDCs, thus accelerating the development of quantum systems in two-dimensional semiconducting TMDCs.

Kinetic magnetism in triangular moiré materials

Magnetic properties of materials ranging from conventional ferromagnetic metals to strongly correlated materials such as cuprates originate from Coulomb exchange interactions. The existence of alternate mechanisms for magnetism that could naturally facilitate electrical control has been discussed theoretically1-7, but an experimental demonstration8 in an extended system has been missing. Here we investigate MoSe2/WS2 van der Waals heterostructures in the vicinity of Mott insulator states of electrons forming a frustrated triangular lattice and observe direct evidence of magnetic correlations originating from a kinetic mechanism. By directly measuring electronic magnetization through the strength of the polarization-selective attractive polaron resonance9,10, we find that when the Mott state is electron-doped, the system exhibits ferromagnetic correlations in agreement with the Nagaoka mechanism.

Sub-THz wireless transmission based on graphene-integrated optoelectronic mixer

Optoelectronics is a valuable solution to scale up wireless links frequency to sub-THz in the next generation antenna systems and networks. Here, we propose a low-power consumption, small footprint building block for 6 G and 5 G new radio wireless transmission allowing broadband capacity (e.g., 10-100 Gb/s per link and beyond). We demonstrate a wireless datalink based on graphene, reaching setup limited sub-THz carrier frequency and multi-Gbit/s data rate. Our device consists of a graphene-based integrated optoelectronic mixer capable of mixing an optically generated reference oscillator approaching 100 GHz, with a baseband electrical signal. We report >96 GHz optoelectronic bandwidth and -44 dB upconversion efficiency with a footprint significantly smaller than those of state-of-the-art photonic transmitters (i.e., <0.1 mm2). These results are enabled by an integrated-photonic technology based on wafer-scale high-mobility graphene and pave the way towards the development of optoelectronics-based arrayed-antennas for millimeter-wave technology.

A quantum ruler for orbital magnetism in moiré quantum matter

For almost a century, magnetic oscillations have been a powerful "quantum ruler" for measuring Fermi surface topology. In this study, we used Landau-level spectroscopy to unravel the energy-resolved valley-contrasting orbital magnetism and large orbital magnetic susceptibility that contribute to the energies of Landau levels of twisted double-bilayer graphene. These orbital magnetism effects led to substantial deviations from the standard Onsager relation, which manifested as a breakdown in scaling of Landau-level orbits. These substantial magnetic responses emerged from the nontrivial quantum geometry of the electronic structure and the large length scale of the moiré lattice potential. Going beyond traditional measurements, Landau-level spectroscopy performed with a scanning tunneling microscope offers a complete quantum ruler that resolves the full energy dependence of orbital magnetic properties in moiré quantum matter.

Evaluation of Liver Functionality after Liver Stereotactic Body Radiation Therapy (SBRT) Using Blood Tests and Imaging Examinations

PURPOSE/OBJECTIVE(S)

Several studies have shown that liver function can be evaluated after hepatic stereotactic body radiation therapy (SBRT) using galactosyl human serum albumin (GSA) liver scintigraphy and Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI). However, there are no reports investigating the relationship (including Chile-Pugh classification) between imaging and blood tests. Therefore, we investigated the changes that occur in the liver between before and after SBRT by combining imaging (GSA, computed tomography (CT), and MRI) with blood tests that assess total liver function (albumin-bilirubin (ALBI) grade, ICG-R15). We decided to find a method that could assess liver reserve capacity locally and globally MATERIALS/METHODS: Of the 23 patients who underwent hepatic SBRT, 12 patients underwent GSA, MRI, and ICG-R15 testing before treatment, 1 month after treatment, and 3 months after treatment. All patients underwent imaging studies and blood tests at the beginning of treatment, 1 month after treatment, and 3 months after treatment ended. The evaluation items were as follows: 1) changes over time in Child-Pugh classification, ICG-R15, and ALBI values before and after SBRT; 2) changes over time in GSA count and ICG; and 3) selection of the optimal sequence for recognizing radiation hepatitis on MRI.

RESULTS

The ICG values were 14.4 before RT, 17.1 after 1 month, and 17.6 after 3 months. ICG worsened after 1 month of treatment, but was similar after 3 months. ALBI values were -2.61 before RT, -2.67 after 1 month, and -2.71 after 3 months. ALBl worsened slightly over time.

CONCLUSION

Regarding the ICG-R15, there was an average worsening of 2.8 after 1 month of treatment compared with before SBRT, but only of 0.5 between 1 month and 3 months after SBRT. Therefore, evaluation using ICG-R15 after SBRT after 1 month alone may be sufficient.

Control of the Bright-Dark Exciton Splitting Using the Lamb Shift in a Two-Dimensional Semiconductor

We investigate the exciton fine structure in atomically thin WSe_{2}-based van der Waals heterostructures where the density of optical modes at the location of the semiconductor monolayer can be tuned. The energy splitting Δ between the bright and dark exciton is measured by photoluminescence spectroscopy. We demonstrate that Δ can be tuned by a few meV as a result of a significant Lamb shift of the optically active exciton that arises from emission and absorption of virtual photons triggered by the vacuum fluctuations of the electromagnetic field. We also measure strong variations of the bright exciton radiative linewidth as a result of the Purcell effect. All these experimental results illustrate the strong sensitivity of the excitons to local vacuum field fluctuations. We find a very good agreement with a model that demonstrates the equivalence, for our system, of a classical electrodynamical transfer matrix formalism and quantum-electrodynamical approach. The bright-dark splitting control we demonstrate here in the weak light-matter coupling regime should apply to any semiconductor structures.

Electrically driven europium-doped GaN microdisk

For the practical implementation of microdisk resonators as active nanophotonic devices, it is essential that they can be electrically driven. However, it is difficult to inject current in such small-scale devices without severely degrading their optical properties. We demonstrate the successful fabrication of an electrically injected microdisk based on Eu-doped GaN, in which an SiO2 spacer is used to prevent the interaction of the metal contact with the optical resonances. The microdisk shows Eu-related emission upon electrical injection and from the observed resonance peak, a cavity quality (Q)-factor of 3400 is concluded.

Prevalence and prognostic value of atrial fibrillation in patients with cardiac sarcoidosis

Aims

The prognostic value of the presence of atrial fibrillation (AF) in patients at the time of cardiac sarcoidosis (CS) diagnosis is unknown. This study aimed to investigate the association between AF at the time of CS diagnosis and patient prognosis.

Methods and results

This study is a post-hoc analysis of Illustration of the Management and Prognosis of Japanese Patients with CS, a multicentre, retrospective observational study that evaluated the clinical characteristics and prognosis of patients with CS. The primary endpoint was the combined endpoint of all-cause death and hospitalization due to heart failure. After excluding patients with missing data about AF status, 445 patients (62 ± 11 years, 36% males) diagnosed with CS according to the Japanese current diagnostic guideline were analysed. Compared to patients without AF, patients with AF (n = 46, 10%) had higher levels of brain natriuretic peptide and a higher prevalence of heart failure hospitalizations. During a median follow-up period of 3.2 years (interquartile range, 1.7-5.8 years), 80 primary endpoints were observed. Kaplan-Meier curve analysis indicated that concomitant AF at the time of diagnosis was significantly associated with a high incidence of primary endpoints (log-rank P = 0.002). This association was retained after adjusting for known risk factors including log-transformed brain natriuretic peptide levels and left ventricular ejection fractions [hazard ratio, 1.96 (95% confidence interval, 1.05-3.65); P = 0.035].

Conclusion

The presence of AF at the time of CS diagnosis is associated with higher incidence of all-cause death and heart failure hospitalization.

Ultrafast exciton fluid flow in an atomically thin MoS2 semiconductor

Excitons (coupled electron-hole pairs) in semiconductors can form collective states that sometimes exhibit spectacular nonlinear properties. Here, we show experimental evidence of a collective state of short-lived excitons in a direct-bandgap, atomically thin MoS2 semiconductor whose propagation resembles that of a classical liquid as suggested by the nearly uniform photoluminescence through the MoS2 monolayer regardless of crystallographic defects and geometric constraints. The exciton fluid flows over ultralong distances (at least 60 μm) at a speed of ~1.8 × 107 m s-1 (~6% the speed of light). The collective phase emerges above a critical laser power, in the absence of free charges and below a critical temperature (usually Tc ≈ 150 K) approaching room temperature in hexagonal-boron-nitride-encapsulated devices. Our theoretical simulations suggest that momentum is conserved and local equilibrium is achieved among excitons; both these features are compatible with a fluid dynamics description of the exciton transport.

National Survey Identifying the Factors Affecting the Career Development of Cardiologists in Japan

BACKGROUND

Equality in training opportunities, studying abroad, and satisfaction with work are not well investigated among Japanese cardiologists.Methods and Results: We studied cardiologists' career development using a questionnaire that was emailed to 14,798 cardiologists belonging to the Japanese Circulation Society (JCS) in September 2022. Feelings regarding equality in training opportunities, preferences for studying abroad, and satisfaction with work were evaluated with regard to cardiologists' age, sex, and other confounding factors. Survey responses were obtained from 2,566 cardiologists (17.3%). The mean (±SD) age of female (n=624) and male (n=1,942) cardiologists who responded to the survey was 45.6±9.5 and 50.0±10.6 years, respectively. Inequality in training opportunities was felt more by female than male cardiologists (44.1% vs. 33.9%) and by younger (<45 years old) than older (≥45 years old) (42.0% vs. 32.8%). Female cardiologists were less likely to prefer studying abroad (53.7% vs. 59.9%) and less satisfied with their work (71.3% vs. 80.8%) than male cardiologists. Increased feelings of inequality and lower work satisfaction were investigated among cardiologists who were young, had family care duties, and had no mentors. In the subanalysis, significant regional differences were found in cardiologists' career development in Japan.

CONCLUSIONS

Female and younger cardiologists felt greater inequality in career development than male and older cardiologists. A diverse workplace may prompt equality in training opportunities and work satisfaction for both female and male cardiologists.

Evaluation of the efficacy and safety of an integrated telerehabilitation platform for home-based cardiac REHABilitation in patients with heart failure (E-REHAB): protocol for a randomised controlled trial

INTRODUCTION

Cardiac rehabilitation (CR) is strongly recommended as a medical treatment to improve the prognosis and quality of life of patients with heart failure (HF); however, participation rates in CR are low compared with other evidence-based treatments. One reason for this is the geographical distance between patients' homes and hospitals. To address this issue, we developed an integrated telerehabilitation platform, RH-01, for home-based CR. We hypothesised that using the RH-01 platform for home-based CR would demonstrate non-inferiority compared with traditional centre-based CR.

METHODS AND ANALYSIS

The E-REHAB trial aims to evaluate the efficacy and safety of RH-01 for home-based CR compared with traditional centre-based CR for patients with HF. This clinical trial will be conducted under a prospective, randomised, controlled and non-inferiority design with a primary focus on HF patients. Further, to assess the generalisability of the results in HF to other cardiovascular disease (CVD), the study will also include patients with other CVDs. The trial will enrol 108 patients with HF and 20 patients with other CVD. Eligible HF patients will be randomly assigned to either traditional centre-based CR or home-based CR in a 1:1 fashion. Patients with other CVDs will not be randomised, as safety assessment will be the primary focus. The intervention group will receive a 12-week programme conducted two or three times per week consisting of a remotely supervised home-based CR programme using RH-01, while the control group will receive a traditional centre-based CR programme. The primary endpoint of this trial is change in 6 min walk distance.

ETHICS AND DISSEMINATION

The conduct of the study has been approved by an institutional review board at each participating site, and all patients will provide written informed consent before entry. The report of the study will be disseminated via scientific fora, including peer-reviewed publications and presentations at conferences.

TRIAL REGISTRATION NUMBER

jRCT:2052200064.

Sex differences in clinical characteristics and prognosis of patients with cardiac sarcoidosis

OBJECTIVE

Owing to the paucity of data, this study aimed to investigate sex differences in clinical features and prognosis of patients with cardiac sarcoidosis (CS).

METHODS

This study was a secondary analysis of the ILLUstration of the Management and prognosIs of JapaNese PATiEnts with Cardiac Sarcoidosis registry-a retrospective multicentre registry that enrolled patients with CS between 2001 and 2017. The primary outcome was potentially fatal ventricular arrhythmia events (pFVAEs)-a composite of sudden cardiac death, sustained ventricular tachycardia lasting >30 s, ventricular fibrillation or the requirement for implantable cardioverter defibrillator therapy.

RESULTS

Of the 512 participants (mean age±SD 61.6±11.4 years), 329 (64.2%) were females. Both sexes had peak ages of 60-64 years at diagnosis. Male patients were younger and had a higher prevalence of coronary artery disease and lower left ventricular ejection fraction than female patients. During a median follow-up of 3 years (IQR 1.6-5.6), pFVAEs were observed in 99 patients, with males having a significantly higher risk than females (p=0.002). This association was retained even after adjustment for other risk factors for pFVAEs, including left ventricular ejection fraction (adjusted HR 1.80; 95% CI 1.08 to 3.01, p=0.025).

CONCLUSION

Approximately two-thirds of patients with CS were females, with a peak age of approximately 60 years at clinical diagnosis in both sexes; male patients were younger than female patients. Male patients had a significantly higher risk of pFVAEs than female patients.

TRIAL REGISTRATION NUMBER

UMIN000034974.