Efficient and tunable liquid crystal random laser based on plasmonic-enhanced FRET

Random lasers (RLs), which possess peculiar advantages (e.g., emission and coherence tunable) over traditional lasers with optical resonators, have witnessed rapid development in the past decades. However, it is still a challenge to tune the lasing peak of an RL over a wide range. Here, a temperature-dependent Förster resonance energy transfer (FRET) RL is demonstrated in pyrromethene 597 (PM597, “donor”) and Nile blue (NB, “acceptor”) doped chiral liquid crystals. By changing the temperature that drives the liquid crystal bandgap shift, our RL device exhibits a lasing output change from 560 nm (yellow) to 700 nm (red). While the intrinsic FRET efficiency between PM597 and NB is relatively low, the red lasing is weak. By introducing gold nanorods (GNRs) into these RL devices and utilizing GNRs’ localized surface plasmon resonance (LSPR) effect, the efficiency of FRET transfer is increased by 68.9%, thereby reducing the threshold of the RL devices. By tuning the longitudinal LSPR to match the emission wavelength of NB, the best 200-fold lasing intensity enhancement is recorded. Our findings open a pathway toward realizing LSPR-enhanced FRET tunable RLs and broaden the range of their possible exploration in photonics research and technologies

Orbital-Dependent Electron Correlation in Double-Layer Nickelate La3Ni2O7

The latest discovery of high temperature superconductivity near 80K in La3Ni2O7 under high pressure has attracted much attention. Many proposals are put forth to understand the origin of superconductivity. The determination of electronic structures is a prerequisite to establish theories to understand superconductivity in nickelates but is still lacking. Here we report our direct measurement of the electronic structures of La3Ni2O7 by high-resolution angle-resolved photoemmission spectroscopy. The Fermi surface and band structures of La3Ni2O7 are observed and compared with the band structure calculations. A flat band is formed from the Ni-3dz2 orbitals around the zone corner which is 50meV below the Fermi level. Strong electron correlations are revealed which are orbital- and momentum-dependent. Our observations will provide key information to understand the origin of high temperature superconductivity in La3Ni2O7.Comment: 18 pages, 4 figure

Visible-Light-Driven Antimicrobial Activity and Mechanism of Polydopamine-Reduced Graphene Oxide/BiVO4 Composite

In this study, a photocatalytic antibacterial composite of polydopamine-reduced graphene oxide (PDA-rGO)/BiVO4 is prepared by a hydrothermal self-polymerization reduction method. Its morphology and physicochemical properties are characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier-transform infrared (FT-IR), and X-ray diffraction (XRD). The results indicate that BiVO4 particles are evenly distributed on the rGO surface. Escherichia coli (E. coli) MG1655 is selected as the model bacteria, and its antibacterial performance is tested by flat colony counting and the MTT method under light irradiation. PDA-rGO/BiVO4 inhibits the growth of E. coli under both light and dark conditions, and light significantly enhances the bacteriostasis of PDA-rGO/BiVO4. A combination of BiVO4 with PDA-rGO is confirmed by the above characterization methods as improving the photothermal performance under visible light irradiation. The composite possesses enhanced photocatalytic antibacterial activity. Additionally, the photocatalytic antibacterial mechanism is investigated via the morphology changes in the SEM images of MG1655 bacteria, 2′,7′-dichlorofluorescein diacetate (DCFH-DA), the fluorescence detection of the reactive oxygen species (ROS), and gene expression. These results show that PDA-rGO/BiVO4 can produce more ROS and lead to bacterial death. Subsequently, the q-PCR results show that the transmembrane transport of bacteria is blocked and the respiratory chain is inhibited. This study may provide an important strategy for expanding the application of BiVO4 in biomedicine and studying the photocatalytic antibacterial mechanism

Experimental Study on Methane Diffusion Characteristics of Different Metamorphic Deformed Coals Based on the Counter Diffusion Method

The diffusion coefficient (D) is a key parameter that characterizes the gas transport occurring in coal seams. Typically, D is calculated using the desorption curve of particle coal. However, this method cannot accurately reflect the diffusion characteristics under the stress constraint conditions of in situ coal seams. In this study, different metamorphic deformed coals of medium and high coal rank were considered based on Fick’s law of counter diffusion. The change laws of D under different confining pressures, gas pressures, and temperature conditions were tested and analyzed, and the influencing mechanisms on D are discussed. The results showed that D of different metamorphic deformed coals exponentially decreased with an increase in confining pressures, and exponentially increased with increases in gas pressures and temperature. There is a limit diffusion coefficient. The influence of the confining pressure on D can essentially be determined by changes in the effective stress, and D negatively affects the effective stress, similar to permeability. The effect of gas pressure on D involves two mechanisms: mechanical and adsorption effects, which are jointly restricted by the effective stress and the shrinkage and expansion deformation of coal particles. Temperature mainly affects D by changing the root-mean-square speed and average free path of the gas molecules. Under the same temperature and pressure conditions, D first increased and then decreased with an increase in the degree of deformation. D of the fragmented coal was the largest. Under similar deformation conditions, D of the high-rank anthracite was larger than that of the medium-rank fat coal. Porosity is a key factor affecting the change in D in different metamorphic deformed coals

Daphnetin Alleviates Senile and Disuse Osteoporosis by Distinct Modulations of Bone Formation and Resorption

Senile and disuse osteoporosis have distinct bone turnover status and lack effective treatments. In this study, senescence-accelerated mouse prone 8 (SAMP8) and hindlimb unloading mouse models were used to explore the protective effects of daphnetin on these two types of osteoporosis, and primary osteoblasts and bone marrow monocyte-derived osteoclasts, as well as pre-osteoblast MC3T3-E1, and osteoclast precursor RAW264.7 cells were used to investigate the underlying mechanisms. The results showed that daphnetin administration effectively improved bone remodeling in both senile and disuse osteoporosis, but with different mechanisms. In senile osteoporosis with low bone turnover, daphnetin inhibited NOX2-mediated ROS production in osteoblasts, resulting in accelerated osteogenic differentiation and bone formation, while in disuse osteoporosis with high bone turnover, daphnetin restored SIRT3 expression, maintained mitochondrial homeostasis, and additionally upregulated SOD2 to eliminate ROS in osteoclasts, resulting in attenuation of osteoclast differentiation and bone resorption. These findings illuminated that daphnetin has promising potential for the prevention and treatment of senile and disuse osteoporosis. The different mechanisms may provide clues and basis for targeted prevention and treatment of osteoporosis according to distinct bone turnover status

Safety and efficacy of intra-articular injection of JTA-004, a novel viscosupplement, in symptomatic knee osteoarthritis: a randomized, double-blind controlled phase II/III study

Objective: The objective was to assess the safety and efficacy of a single intra-articular administration of JTA-004, a novel viscosupplement, in patients suffering from symptomatic knee osteoarthritis (OA) at 6 months. Design and methods: In this prospective, multicenter, double-blind phase II/III trial (NCT02740231), 164 patients with primary OA knee pain were randomly assigned to one of the three JTA-004 strengths or the comparator treatment (Hylan G-F 20) in a 1:1:1:1 ratio. Safety was assessed by monitoring and reporting vital signs, physical examination, adverse events and concomitant medications. The primary efficacy endpoint was the change from baseline at 6 months in WOMAC® VA3.1 pain subscale. Results: JTA-004 was shown to be well tolerated at all strengths evaluated. At 6 months, patients in the three JTA-004 groups showed a better improvement in pain compared to patients in the comparator group although statistical significance was not achieved. As the three JTA-004 strengths had a similar efficacy, a post hoc analysis was subsequently performed between the pooled JTA-004 treated patients and the comparator group. The exploratory analysis showed a 26.1±2.4 (adjusted mean±SE) mm improvement in pain in the pooled JTA-004 group vs. 15.6±4.1 mm in the comparator group at 6 months, demonstrating a statistically significant superiority of JTA-004 over the comparator (p = 0.030). Conclusions: This study provides first evidences of safety and efficacy of JTA-004 in the treatment of symptomatic knee OA. Efficacy will be further confirmed in a subsequent pivotal Phase III study

Orbital-dependent electron correlation in double-layer nickelate La3Ni2O7

Abstract The latest discovery of high temperature superconductivity near 80 K in La3Ni2O7 under high pressure has attracted much attention. Many proposals are put forth to understand the origin of superconductivity. The determination of electronic structures is a prerequisite to establish theories to understand superconductivity in nickelates but is still lacking. Here we report our direct measurement of the electronic structures of La3Ni2O7 by high-resolution angle-resolved photoemission spectroscopy. The Fermi surface and band structures of La3Ni2O7 are observed and compared with the band structure calculations. Strong electron correlations are revealed which are orbital- and momentum-dependent. A flat band is formed from the Ni-3d $${}_{{z}^{2}}$$ z 2 orbitals around the zone corner which is ~ 50 meV below the Fermi level and exhibits the strongest electron correlation. In many theoretical proposals, this band is expected to play the dominant role in generating superconductivity in La3Ni2O7. Our observations provide key experimental information to understand the electronic structure and origin of high temperature superconductivity in La3Ni2O7