Room-temperature quantum emission from interface excitons in mixed-dimensional heterostructures

The development of van der Waals heterostructures has introduced unconventional phenomena that emerge at atomically precise interfaces. For example, interlayer excitons in two-dimensional transition metal dichalcogenides show intriguing optical properties at low temperatures. Here we report on room-temperature observation of interface excitons in mixed-dimensional heterostructures consisting of two-dimensional tungsten diselenide and one-dimensional carbon nanotubes. Bright emission peaks originating from the interface are identified, spanning a broad energy range within the telecommunication wavelengths. The effect of band alignment is investigated by systematically varying the nanotube bandgap, and we assign the new peaks to interface excitons as they only appear in type-II heterostructures. Room-temperature localization of low-energy interface excitons is indicated by extended lifetimes as well as small excitation saturation powers, and photon correlation measurements confirm antibunching. With mixed-dimensional van der Waals heterostructures where band alignment can be engineered, new opportunities for quantum photonics are envisioned.

Epicardial adipose tissue volume is associated with low-attenuation plaque volume in subjects with or without increased visceral fat: a 3-vessel coronary artery analysis with CT angiography

Background

Low-attenuation plaque (LAP) with a CT value of less than or equal 30 HU on coronary CT angiography (CCTA) is a marker of high-risk plaque features that leads to future acute coronary syndromes. Perivascular and epicardial adipose tissue (EAT) have been shown to be associated with progression of high-risk coronary plaques through metabolic and inflammatory mechanisms. However, association of EAT with LAP volume in three coronary arteries in subjects with or without visceral obesity remain unclear.

Aims

This study aimed to investigate the association of EAT volume (EAV) and coronary 3-vessel LAP volume in subjects with or without visceral obesity who underwent CCTA.

Methods

Patients who underwent CCTA without known coronary artery disease were included in the study (525 patients). Study subjects were classified as having non-obstructive or obstructive coronary artery disease according to the degree of coronary artery stenosis on CCTA. The plaque volume and EAV of the main vessel of the left anterior descending artery, left circumflex artery, and right coronary artery were measured with VINCENT software. Coronary plaque composition was classified as calcified plaque (CP, >150HU), noncalcified plaque (NCP, 30–150HU), and Lap (<30HU). The %LAP volume of the three coronary arteries was classified into quartiles. Multiple logistic regression analysis was used to analyze the factors associated with the %LAP volume.

Results

Compared with subjects without increase visceral fat, subjects with increased visceral fat had a significantly higher BMI, a greater total plaque volume, a greater total %LAP volume, a greater EAV, and a lower mean CT value of EAT. A significant correlation was observed between EAV and %LAP volume (R=0.24, p<0.001). EAV (odds ratio; 1.83, 95% confidence interval 1.071–3.141, p-value 0.027) and type 2 diabetes mellitus (odds ratio 1.76, 95%confidence interval 1.042–3.000, p-value 0.034) appeared to be independent predictors of %LAP volume (Q4), when adjusted by age, gender, BMI>25 kg/m2, visceral fat >100cm2, LogCRP, coronary artery calcium score>300, and obstructive coronary artery disease requiring revascularization.

Conclusion

This study suggests that LAP volume, which reflects the high-risk plaques in the three coronary arteries, is associated with EAV in subjects with or without increased visceral fat. Further research is needed whether pharmacological therapeutic intervention enables the prevention of coronary plaque progression and destabilization through the reduction of EAV in patients.

Funding Acknowledgement

Type of funding sources: None.

Clinical significance of aortic arch plaques simultaneously assessed with coronary atherosclerosis on cardiovascular outcomes in patients undergoing coronary CT angiography

Aims

Computed tomography (CT) coronary angiography is a useful diagnostic imaging modality in assessing presence, severity, and extent of coronary artery disease (CAD). Aortic arch plaques have been shown to be an underlying cause of embolic stroke and also related to increased risk of cardiovascular events. Yet, conventional CTCA imaging protocol does not include aortic arch for the reduction of radiation exposure. This study aimed to investigate prevalence of aortic arch plaques simultaneously assessed by CTCA and their clinical significance in combination with the presence of obstructive CAD for prediction of CVD events in patients with suspected CAD.

Methods

This study consisted of 310 (mean age, 66 years old, 42% female) patients with suspected CAD undergoing CTCA between 2017 and 2019. All CTCA examination was performed with 320-row detector scanner using ECG-triggered prospective gating method. Aortic arch images were simultaneously acquired during CTCA scanning without an increase of contrast media. Using Agatston method, coronary artery calcium score (CACS) was categorized into either of the groups having CACS of 0, 0–99, 100–299, or more than 300. The presence of CAD was reported as non-obstructive or obstructive CAD. High-risk featured aortic plaque was defined as large plaques >4 mm in thickness showing ulceration or protrusion. A composite event of cardiovascular disease, including all-cause mortality, non-fatal myocardial infarction, unplanned hospitalization requiring revascularization or stroke was defined as the primary endpoint.

Results

Patients having CACS of 0, 0–99, 100–299, and >300 were found in 41%, 24%, 15%, 20%%, respectively, where obstructive CAD was diagnosed in 11%. Aortic HRPs in ascending aorta, aortic arch, and thoracic descending aorta were observed in 1.6%, 6.9%, and 15%, respectively. During a mean follow-up period of 2.2 years, the primary endpoint was observed in 27 patients (8.7%). Cox regression hazard model demonstrated an independent association of aortic arch high-risk plaques (HR; 3.2, 95% CI; 1.20–8.64, p=0.02) and obstructive CAD (HR; 3.3, 95% CI; 1.45–7.92, P=0.005) when adjusted by age, CACS, and chronic kidney disease. Kaplan-Meier curve analysis showed a worse outcome of patients with aortic HRP and obstructive CAD compared to those without aortic plaques and obstructive CAD (p<0.001).

Conclusion

This study demonstrated an independent association of aortic arch high-risk featured plaques with CVD events. Further study is warranted whether pharmacological interventional therapies can reduce future CVD risks in patients with CAD and aortic arch plaques.

Funding Acknowledgement

Type of funding sources: None.

Intracoronary polarimetry for characterizing coronary plaque vulnerability in patients with coronary artery disease

Background

Intracoronary polarimetry with polarization-sensitive (PS-) optical frequency domain imaging (OFDI) measures polarization properties, including birefringence and depolarization, in parallel with structural features of conventional OFDI (Figure 1A). Collagen, which imparts mechanical integrity to fibrous caps, and collagen-synthesizing smooth muscle cells exhibit elevated birefringence. Depolarization is increased by the presence of macrophages and lipid/necrotic cores.

Purpose

This study aimed to compare conventional OFDI and polarimetric signatures of coronary lesions between patients with acute coronary syndrome (ACS) and chronic coronary syndrome (CCS). Furthermore, we aimed to determine a birefringence cut-off value for identifying which fibrous caps belong to ACS culprit lesions.

Methods

This study consisted of 37 patients with ACS (n=23) or CCS (n=14). ACS culprit lesions (ACS-lesions) and CCS stenotic lesions (CCS-lesions) were included in the analysis (820 mm). Qualitative and quantitative conventional OFDI analysis included the presence of plaque rupture, macrophage infiltration, micro-vessels, thrombus, stenosis severity, fibrous cap thickness (FCT), lipid arc, lipid-burden and calcium-burden index. Birefringence and depolarization of the coronary lesions and fibrous caps were measured in the cross-sectional images showing the minimum FCT or minimum luminal area. Predictors of ACS-lesions were investigated by multivariate regression analysis. Receiver operating characteristic (ROC) analysis was used to determine the birefringence cut-off value identifying ACS fibrous caps (ACS-caps).

Results

There were no significant differences in clinical characteristics between the two groups, except for previous history of coronary artery disease. Compared to CCS-lesions, ACS-lesions featured higher lipid-burden index and maximum lipid arc (both p<0.05). ACS-lesions featured lower birefringence and higher depolarization than CCS-lesions (p<0.05). Multivariable regression demonstrated an independent association of birefringence with ACS-lesions (p<0.05), even after adjusting for the conventional OFDI findings. Limiting the analysis to the fibrous caps, ACS-caps exhibited significantly lower birefringence (p<0.05) and higher depolarization (p<0.05) that CCS-caps. ROC analysis for differentiating ACS-caps from CCS-caps found that a birefringence value of 0.0004 results in a sensitivity and specificity of 88% and 82%, respectively (Figure 1B, AUC = 0.82).

Conclusions

Intracoronary polarimetry provides quantitative assessment of coronary lesions related to their composition. Birefringence was an independent robust predictor of ACS-lesions. Decreased birefringence and pronounced depolarization within the ACS-caps may indicate increased collagenolytic activity and macrophage infiltration, respectively. These results suggest that polarization properties may serve as quantitative imaging markers for assessing plaque vulnerability.

Figure 1

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): This work was supported by the National Institutes of Health and by Terumo Corporation.

Polarization-sensitive OFDI findings of vascular tissue response following drug-eluting stent implantation in patients with coronary artery disease

 

Intravascular polarimetry (IVP) with polarization-sensitive (PS-) optical frequency domain imaging (OFDI) measures polarization properties of the coronary arterial wall in parallel with the conventional OFDI images (Figure 1A). Tissues rich in collagen and smooth muscle cells (SMCs) appear birefringent, while the presence of lipid and macrophages causes depolarization. Because drug-eluting stents (DES) are designed to prevent SMC proliferation and collagen deposition, we hypothesized that neointimal tissue would exhibit low birefringence. The accumulation of lipid-laden macrophages characteristic of neoatherosclerosis should result in notable depolarization.

Methods

This study included 19 DES imaged with PS-OFDI in 13 patients (median follow-up period of 1.5 years). Coronary segments stented >90 days were analyzed every 1 mm. We analyzed polarization properties of the neointima in a total of 455 frames, and in additional 97 frames of native atherosclerosis remote from the stented segments. Neointima, delineated by the lumen and the inner boundary of the stent, was manually segmented in the intensity images using MATLAB. The median birefringence in all areas of the segmented neointima featuring a depolarization of ≤0.2 and the median depolarization across the entire neointima were computed for each frame after masking the guidewire shadow. Frames presenting intensity features of macrophages, lipid or calcifications extending to at least one adjacent frame were classified as neoatherosclerosis (n=112), and otherwise as normal neointima (n=343). For comparison with neoatherosclerosis, polarization properties of native atherosclerosis (n=97) were measured. We also categorized all frames of a stented segment according to the presence of in-stent restenosis (ISR) and/or stent thrombosis (ST) (204 frames from 5 patients). A generalized linear model using a generalized estimating equation or one-way ANOVA was used for statistical analysis.

Results

The major findings of the present study are: 1) neoatherosclerosis exhibited lower birefringence than native atherosclerosis (p<0.001, Figure-1B); 2) depolarization was positively associated with neoatherosclerosis (β=0.86, p<0.001) and ISR/ST (β=0.72, p=0.002), while birefringence was not (Figure 1C); 3) birefringence was positively correlated with the duration after DES implantation (β=5.22×10–3, p<0.001, Figure 1D). For the detection of neointimas within stents with ISR, the best cut-off value for depolarization was 0.033 with a sensitivity of 77% and a specificity of 57% (AUC=0.72). For comparison, using only conventional OFDI parameters to detect stents with ISR, the AUC were 0.52 for calcium area, 0.62 for lipid arc, and 0.63 for macrophage accumulations.

Conclusions

This study suggests that IVP provides quantitative assessment of vascular healing after DES implantation and may help clinical decision making in patients at high risk of stent failure.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This work was supported by the National Institutes of Health.

P176 Left ventricular diastolic function by gated myocardial perfusion SPECT strongly reflects NT-ProBNP

Background

The importance of left ventricle diastolic dysfunction (LVDD) has been recognized widely, as it is well established that heart failure with preserved ejection fraction has a poor prognosis. Furthermore, N-terminal pro–B-type natriuretic peptide (NT-ProBNP) is used as a marker of heart failure. However, the association between LVDD and NT-proBNP is unclear. 

Purpose

The aim of this study was to clarify the association between LVDD and NT-ProBNP. 

Methods

In this study, an index based on gated myocardial perfusion SPECT using CardioREPO software for the diagnosis of LVDD was used. Out of the 171 patients who underwent myocardial perfusion imaging (MPI) between January 2015 and December 2018, 163 individuals (116 men and 47 women) completed MPI and NT-ProBNP. Patients were classified into 4 groups: NT-ProBNP levels below 125 pg/ml (n = 52), NT-ProBNP levels 125 to 400 pg/ml (n = 33), NT-ProBNP levels 400 to 900 pg/ml (n = 23), and NT-ProBNP levels over 900 pg/ml (n = 37). CardioREPO parameters (peak filling rate　(PFR), 1/3 mean filling rate (MFR), and time to peak filling rate/R-R (TTPFR)) were compared between the 4 NT-ProBNP groups. 

Results

Of the 163 patients, 55 had LVDD. The PFR and 1/3MFR were associated with LVDD. There was a statistically significant difference in PFR and 1/3 MFR between the NT-ProBNP levels below 125 pg/ml group and the NT-ProBNP levels 400 to 900 pg/ml group (PFR = 2.51+/-1.11 vs. 1.80+/-0.65, p = 0.001; 1/3 MFR = 1.41+/-0.55 vs. 1.06+/-0.47, p = 0.006, Table).

Conclusions

The MPI indices obtained by CardioREPO software were useful in the diagnosis of LVDD. The evaluation of LVDD by MPI correlated with NT-Pro BNP level is thought to have a clinical utility in the diagnosis and management of LVDD.

Variable: NT-ProBNP 　 0-125 (n = 52) 125-400 (n = 33) 400-900 (n = 23) 900- (n = 37) p Age 66 ± 11 72 ± 11 68 ± 17 70 ± 12 0.133 Male 40 (77%) 22 (12%) 18 (78%) 23 (62%) 0.36 Left ventricular diastolic dysfunction 8 (15%) 4 (12%) 10 (43%) 27 (73%) <0.001 E/A 0.9 ± 0.3 0.8 ± 0.2 1.1 ± 0.7 1.4 ± 0.9 (35) <0.001 E/e" 10.27 ± 3.69 (20) 8.83 ± 3.56 (10) 12.46 ± 3.75 (12) 20.25 ± 8.30 (25) <0.001 rest-PFR /s 2.51 ± 1.11 2.06 ± 0.58 2.16 ± 0.65 1.80 ± 0.65 0.001 rest-1/3 MFR /s 1.41 ± 0.55 1.19 ± 0.41 1.16 ± 0.50 1.06 ±0.47 0.008 rest-TTPFR ms 177 ± 53 181 ± 69 198 ± 80 166 ± 85 0.38 rest-TTPFR / R-R 　 0.19 ± 0.06 0.20 ± 0.11 0.21 ±0.09 0.21 ± 0.15 0.92

Stability of cervical esophagogastrostomy via hand-sewn anastomosis after esophagectomy for esophageal cancer

The aim of the present study is to evaluate the outcome of hand-sewn esophagogastric anastomosis during radical esophagectomy for esophageal cancer. The outcomes of 467 consecutive esophageal cancer patients who underwent cervical esophagogastric anastomosis using interrupted and double-layered sutures after radical esophagectomy via right thoracotomy or thoracoscopic surgery were retrospectively reviewed. Anastomotic leakage, including conduit necrosis, occurred in 11 of 467 patients (2.4%); 7 of 11 (63.6%) cases experienced only minor leakage, whereas the other four (36.4%) patients had major leakage that required surgical or radiologic intervention, including two patients of conduit necrosis. Anastomotic leakages were more frequently observed after retrosternal reconstruction compared with the posterior mediastinal route (P < 0.0001). The median time to healing of leakage was 40 days (range: 14-97 days). Two patients (2/467, 0.4%) died in the hospital due to sepsis caused by the leakage and conduit necrosis. Twelve patients (2.6%) developed anastomotic stenosis, which was improved by dilatation in all patients. Hand-sewn cervical esophagogastric anastomosis is a stable and highly safe method of radical esophagectomy for esophageal cancer.

IL4Rα and ADAM33 as genetic markers in asthma exacerbations and type-2 inflammatory endotype

BACKGROUND

Genetic markers of susceptibility to asthma exacerbations in adults remain unclear.

OBJECTIVE

To identify genetic markers of asthma exacerbations, particularly in patients with type-2 inflammatory endotype.

METHODS

In this observational study of patients enrolled in the Kinki Hokuriku Airway disease Conference multicenter study, frequency of exacerbations requiring systemic corticosteroids during 2 years after enrolment and associated risk factors was determined. For genetic marker analysis, interleukin-4 receptor α (IL4RA) rs8832 and a disintegrin and metalloprotease 33 (ADAM33) S_2 (rs528557), T_1 (rs2280091), T_2 (rs2280090), and V_4 (rs2787094) variants were included. Elevated serum periostin levels at enrolment (≥95 ng/mL, defined as type-2 inflammatory endotype) were considered in the analysis.

RESULTS

Among 217 patients who were successfully followed up for 2 years after enrolment, 60 patients showed at least one asthma exacerbation during the 2 years. Airflow limitation (%FEV₁ <80%) and recent exacerbations but not genetic variants were identified as risk markers of exacerbations. A total of 27 patients showed type-2 inflammatory endotype (serum periostin ≥95 ng/mL at enrolment) and subsequent exacerbations; risk factors in these patients were airflow limitation (odds ratio, 6.51; 95% confidence interval (CI): 2.37-18.6; P=.0003), GG genotype of IL4RA rs8832 (odds ratio, 4.01; 95% CI: 1.47-11.0; P=.007), and A allele of ADAM33 T_2 (odds ratio, 2.81; 95% CI: 1.05-7.67; P=.04) by multivariate analysis. In addition, GG genotype of IL4RA rs8832 was associated with type-2 endotype, whereas A allele of ADAM33 T_2 was associated with mixed type of eosinophilic/type-2 and neutrophilic inflammations.

CONCLUSIONS AND CLINICAL RELEVANCE

IL4RA and ADAM33 variants may be risk markers of asthma exacerbations in type-2 inflammatory endotype. Precise endotyping may facilitate the identification of genetic risk markers of asthma exacerbations.

Observation of motion of colloidal particles undergoing flowing Brownian motion using self-mixing laser velocimetry with a thin-slice solid-state laser

We achieved a highly sensitive method for observing the motion of colloidal particles in a flowing suspension using a self-mixing laser Doppler velocimeter (LDV) comprising a laser-diode-pumped thin-slice solid-state laser and a simple photodiode. We describe the measurement method and the optical system of the self-mixing LDV for real-time measurements of the motion of colloidal particles. For a condensed solution, when the light scattered from the particles is reinjected into the solid-state laser, the laser output is modulated in intensity by the reinjected laser light. Thus, we can capture the motion of colloidal particles from the spectrum of the modulated laser output. For a diluted solution, when the relaxation oscillation frequency coincides with the Doppler shift frequency, f_d, which is related to the average velocity of the particles, the spectrum reflecting the motion of the colloidal particles is enhanced by the resonant excitation of relaxation oscillations. Then, the spectral peak reflecting the motion of colloidal particles appears at 2×f_d. The spectrum reflecting the motion of colloidal particles in a flowing diluted solution can be measured with high sensitivity, owing to the enhancement of the spectrum by the thin-slice solid-state laser.