Mapping of Long-Wavelength Phonon Contribution in the Thermal Transport of Alloyed Semiconductor Superlattices.

The mapping of long-wavelength phonons is important to understand and manipulate the thermal transport in multilayered structures, but it remains a long-standing challenge due to the collective behaviors of phonons. In this study, an experimental demonstration of mapping the long-wavelength phonons in an alloyed Al0.1Ga0.9As/Al0.9Ga0.1As superlattice system is reported. Multiple strategies to filter out the short- to mid-wavelength phonons are used. The phonon mean-free-path-dependent thermal transport properties directly demonstrate both the suppression effect of the ErAs nanoislands and the contribution of long-wavelength phonons. The contribution from phonons with mean free path longer than 1 µm is clearly demonstrated. A model based on the Boltzmann transport equation is proposed to calculate and describe the thermal transport properties, which depicts a clear physical picture of the transport mechanisms. This method can be extended to map different wavelength phonons and become a universal strategy to explore their thermal transport in various application scenarios.

Knockdown of Chitinase 3-Like-1 Inhibits Cell Proliferation, Promotes Apoptosis, and Enhances Effect of Anti-Programmed Death Ligand 1 (PD-L1) in Diffuse Large B Cell Lymphoma Cells.

BACKGROUND Enzymatically inactive chitinase-like protein CHI3L1 is overexpressed in diffuse large B cell lymphoma (DLBCL) patients with PD-L1 imbalance and promotes tumor progression in the microenvironment. Based on this, we investigated how CHI3L1 acts on the proliferation and apoptosis of DLBCL and whether there is a synergy of CHI3L1 in combination with anti-PD-L1 antibodies in vivo. MATERIAL AND METHODS CHI3L1 was detected by quantitative real-time PCR (RT-PCR) and western blot (WB) in B-lymphoma cell lines. CHI3L1 interference plasmids were constructed, and the levels of proliferation, cell cycle, apoptosis, and cell survival were examined in vitro in B-lymphoma cell lines and in vivo in a murine xenograft model by RT-PCR, WB, CCK-8, and flow cytometry. RESULTS CHI3L1 was significantly expressed in SU-DHL-4 cells. CHI3L1-interfered RNA ShRNA-CHI3L1-1 was chosen to be used in the next experiment because it had a better interference effect. Dampened cell proliferation level, arrested cell cycle, reduced protein expressions of cyclin D1 and cyclin D2, and promoted cell apoptosis level were observed after SU-DHL-4 was transfected with ShRNA-CHI3L1-1. Furthermore, we also noticed increased expression of Bcl-2, decreased expressions of bax, cleaved caspase 3 and cleaved PARP, promoted cell survival-related protein p53, and reduced survivin. CONCLUSIONS This study demonstrated that knockdown of CHI3L1 inhibits cancer cell proliferation by regulating cell cycles, promotes cancer cell apoptosis, and enhances the pro-apoptotic effect of anti-PD-L1 antibody both in vivo and in vitro in DLBCL.

Anisotropic dielectric behavior of layered perovskite-like Cs3Bi2I9 crystals in the terahertz region.

The ternary metal halide perovskites have gradually attracted attention for application in the optoelectronic field, owing to their tunable crystal structure and appropriate bandgap. Lead free Cs3Bi2I9 perovskite, with a 0D layered structure containing molecular [Bi2I9]3- dimers, exhibits prominent optical and electrical anisotropies. Here, the anisotropic properties of the Cs3Bi2I9 crystals were evaluated using terahertz time-domain spectroscopy (THz-TDS); meanwhile, the effect of phonon vibration on the THz transmission was confirmed using density functional perturbation theory (DFPT). Accordingly, the refractive index and extinction coefficient are estimated using THz-TDS, thanks to the high transmission in the range of 0.2-0.9 THz. The anisotropic refractive index was observed for the Cs3Bi2I9 crystals, and was found to be 3.2-3.7 for the (100) plane (CBI(100)) in contrast to 2.8-3.2 for the (001) plane (CBI(001)). Furthermore, the Lorentz model was employed to extract the dielectric constant of Cs3Bi2I9, in which anisotropy is obviously indicated by the static dielectric constant and the high-frequency dielectric constant. These anisotropic behaviors are determined by the dipole moment, which is attributed to the anisotropic packing density of [Bi2I9]3- dimers. This study is significant and provides a deeper insight into the anisotropic photoelectric properties of Cs3Bi2I9, thus contributing to the development of metal halide perovskites in the field of optoelectronics.

Secondary Phase Particles in Cesium Lead Bromide Perovskite Crystals: An Insight into the Formation of Matrix-Controlled Inclusion.

The metal halide perovskite CsPbBr3 bulk crystals present electrical and optical performance discrepancy since the grown-in defects. Here, we first report the well-defined secondary phase (SP) particles of CsPb2Br5 with polyhedral morphology in CsPbBr3 crystals grown by the vertical Bridgman method. The resulting polyhedral morphology of CsPb2Br5 particles associated with the trapping of PbBr2-rich droplets have been discussed on the basis of the "matrix-controlled" growth. Two morphological evolution paths are proposed, which result in a regular cube SP particle comprised by {100} facets for the final equilibrium. Furthermore, the wafer with superior optical transmittance exhibits a higher photoelectric response on-off ratio (∼2000) in contrast to ∼80 for the wafer with high density SP particles. The corresponding hole mobility (µh) is calculated with the values 289.99 and 26.91 cm-2·V-1·s-1, respectively. The variation of µh is attributed to the carrier transport trajectory affected by SP induced trapping defects and the weak combination.

[The expression of vascular endothelial growth factor antibody in serum of coal workers with pneumoconiosis].

OBJECTIVE: To determine the role of serum VEGF-Ab in pneumoconiosis of coal workers. METHODS: Four groups of participants were recruited for this study, including 230 with early stage (less serious than stage one) changes in relation to pneumoconiosis, 328 with confirmed coal worker pneumoconiosis, 309 workers exposed to coal dust, and 393 healthy people. All participants completed a questionnaire, and have their peripheral venous blood sample taken. Serum VEGF-Ab was detected by ELISA. RESULTS: Compared with healthy controls and those with early stage changes, the participants with pneumoconiosis and those exposed to coal dust had higher levels of serum VEGF-Ab (P < 0.05). The level of serum VEGF-Ab increased with the progression of stages of pneumoconiosis but without statistical significance (P > 0.05). In those with early stage pneumoconiosis, higher levels of serum VEGF-Ab were found in their 20 yr. - and 40 yr. - compared with those in their 60 yr. - (P < 0.05). By contrast, in those with confirmed pneumoconiosis and the healthy controls, lower levels of serum VEGF-Ab were found in their 20 yr. - and 40 yr. - compared with those in their 60 yr. - (P < 0.05). In those with early stage or first-stage pneumoconiosis, longer than 25 years work experience was associated with higher levels of serum VEGF-Ahb (P < 0.05). In those with confirmed pneumoconiosis, coal mining workers had a higher level of serum VEGF-Ab than their colleagues involving in assistance tasks (P < 0.05). In those exposed to coal dust, tunnelling workers had a higher level of serum VEGF-Ab than their coal mining colleagues (P < 0.05). CONCLUSION: Serum VEGF-Ab is associated with the occurrence and development of coal worker pneumoconiosis. The level of serum VEGF-Ab increases with age and length of exposure to dust.