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Polariton lasing is a new type of lasing that realizes ultra-low threshold lasing with the coherence of Bose-Einstein condensation (BEC) of exciton-polariton in semiconductors. Unlike conventional 3-D organic and inorganic materials, 2-D transition metal dichalcogenides and 2-D perovskite show great potential in the further development of polariton lasing due to their high exciton binding energies, high oscillator strengths, direct band gaps, van der Waals properties, and valley polarization properties, which are conducive to the realization of strong coupling of exciton and cavity modes and BEC of exciton-polariton. In this review, the principle and progress of polariton lasing in 2-D transition metal chalcogenides and perovskite were mainly focused on, starting with development of strong coupling between exciton and cavity modes. Then, the modulation of the coherence of polariton, the realization of the BEC and polariton lasing was introduced. Finally, an outlook will be given on the future development of polariton lasing in 2-D materials. [ABSTRACT FROM AUTHOR]

In this study, unsteady numerical simulations of centrifugal compressors with and without volute were carried out. The unsteady two-phase region evolution in the centrifugal compressor is obtained. Large coherent perturbations were revealed by the decomposition of the transient flow data using the dynamic mode decomposition (DMD) approach. The results imply that because of the low static pressure strip LP1, the two-phase region presents a triangular distribution at the blade leading edge (LE) of the pressure surface (PS) side in one impeller rotation period for both a low flow rate and the design flow rate. At a high flow rate, the two-phase region displays a double triangle distribution on the PS side of the blade LE, which is correlated with the low static pressure strips LP1 and LP2. The maximum two-phase region on the PS side of the LE of the blade occurs downstream of the LP1 position. The two-phase region in the tip clearance is deflected along the LP1 trajectory. DMD analysis shows that there are four modes related to the two-phase region in the tip clearance: mean flow mode with a frequency of 0 Hz and three modes with frequencies of 0.5, 1.0, and 1.5 BPF respectively. Furthermore, the circumferential local perturbation region of these four modes has the same deflection trajectory as that of LP1. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to evaluate coronary inflammation by measuring the perivascular fat attenuation index (FAI) and quantify the atherosclerosis burden in patients with psoriasis and control individuals without psoriasis based on coronary computed tomography angiography (CCTA) images. Methods: A total of 98 consecutive patients with psoriasis (76 male [77.6%], aged 56.5 years, range 45.5–65.0) were recruited, and 196 patients (157 male [80.1%]; aged 54.6 ± 14.1 years) without established cardiovascular disease (CVD) who underwent CCTA within the same period were enrolled in the control group. Coronary plaque burden was quantified using the computed tomography-adapted Leaman score (CT-LeSc), and the FAI surrounding the proximal of three main epicardial vessels was measured to represent coronary inflammation. Results: Patients with psoriasis and the control subjects were well matched in CVD risk factors (all p > 0.05). Psoriasis patients had a greater overall CT-LeSc (5.86 vs. 4.69, p = 0.030) and lower perivascular FAI (−80.19 ± 7.48 vs. −78.14 ± 7.81 HU, p < 0.001). A similar result was found upon comparing psoriasis patients without biological or statin therapy with non-psoriasis individuals without statin treatments. Furthermore, the psoriasis group had a higher prevalence of non-calcified plaques (30.3% in the psoriasis group vs. 20.1% in the control subjects, p = 0.001). No difference in perivascular FAI on either calcified and mixed plaques or non-calcified plaques between the two groups was found. Conclusion: Patients with psoriasis have a higher atherosclerotic burden as quantified by CT-LeSc and less coronary inflammation as detected by perivascular FAI around the most proximal of the three major epicardial vessels. The usefulness of perivascular FAI for evaluating coronary inflammation in patients with chronic low-grade inflammatory disease such as psoriasis should be verified. [ABSTRACT FROM AUTHOR]