Tuning the Flat Band in Bi2O2Se by Pressure to Induce Superconductivity.

The discovery of superconductivity in twisted bilayer graphene has reignited enthusiasm in the field of flat-band superconductivity. However, important challenges remain, such as constructing a flat-band structure and inducing a superconducting state in materials. Here, we successfully achieved superconductivity in Bi2O2Se by pressure-tuning the flat-band electronic structure. Experimental measurements combined with theoretical calculations reveal that the occurrence of pressure-induced superconductivity at 30 GPa is associated with a flat-band electronic structure near the Fermi level. Moreover, in Bi2O2Se, a van Hove singularity is observed at the Fermi level alongside pronounced Fermi surface nesting. These remarkable features play a crucial role in promoting strong electron-phonon interactions, thus potentially enhancing the superconducting properties of the material. These findings demonstrate that pressure offers a potential experimental strategy for precisely tuning the flat band and achieving superconductivity.

Superconductivity in Layered van der Waals Hydrogenated Germanene at High Pressure.

The emergence of superconductivity in two-dimensional (2D) materials has attracted tremendous research efforts because the origins and mechanisms behind the unexpected and fascinating superconducting phenomena remain unclear. In particular, the superconductivity can survive in 2D systems even with weakened disorder and broken spatial inversion symmetry. Here, structural and superconducting transitions of 2D van der Waals (vdW) hydrogenated germanene (GeH) are observed under compression and decompression processes. GeH possesses a superconducting transition with a critical temperature (Tc) of 5.41 K at 8.39 GPa. A crystalline to amorphous transition occurs at 16.80 GPa, while superconductivity remains. An abnormal increase of Tc up to 6.11 K was observed during the decompression process, while the GeH remained in the 2D amorphous phase. A combination study of in situ high-pressure synchrotron X-ray diffraction, in situ high-pressure Raman spectroscopy, transition electron microscopy, and density functional theory simulations suggests that the superconductivity in 2D vdW GeH is attributed to the increased density of states at the Fermi level as well as the enhanced electron-phonon coupling effect under high pressure even in the form of an amorphous phase. The unique pressure-induced phase transition of GeH from 2D crystalline to 2D amorphous metal hydride provides a promising platform to study the mechanisms of amorphous hydride superconductivity.

Pressure-induced photoluminescence enhancement of CeF3:Tb3+ nanoparticles.

Rare earth fluorides have been widely used in recent years in the field of solid-state lighting. However, the relationship between the structure and luminescence properties is still unclear. Herein, the photoluminescence and structural transition of CeF3:Tb3+ nanoparticles under high pressure were investigated through in situ photoluminescence and X-ray diffraction measurements. Intriguingly, the photoluminescence of CeF3:Tb3+ nanoparticles displays an enhancement from 18.3 to 33.4 GPa, accompanied by the phase transition from the starting hexagonal phase to the orthorhombic phase. It was found that the distance of luminescent centers increased sharply during the high-pressure phase transition, which weakened the quenching effect and improved transmission efficiency. Our work provides more insight into the optical characteristics and structures of rare earth trifluorides.

Establishment of a Novel Baculovirus-Silkworm Expression System.

The baculovirus vector expression system is a well-established tool for foreign protein production and gene delivery. In this study, we constructed a recombinant baculovirus vector system. The UAS promotor region and Bombyx mori nucleopolyhedrovirus (BmNPV) polyhedrin coding region were ligated into a pFastBac Dual vector to obtain a BmBac-UPS recombinant bacmid. The recombinant bacmid BmBac-Gal4 was generated by the same strategy which has a Gal4 coding region controlled by the IE2 promoter. BmBac-UPS and BmBac-IGal4 were co-infected into silkworm BmN cells to confirm the ability of the UAS/Gal4 system to form polyhedrons in B. mori cells. Furthermore, the recombinant viruses were tested for infection efficiency and the ability to generate polyhedra in transgenic B. mori cell line BmE. The results showed that recombinant viruses have the ability to form polyhedrons and gain raised pathogenicity when orally infected B. mori larvae and are applied as the preferred tool for foreign gene delivery and expression.

Pressure-Driven Abnormal Emission Blue-Shift of Lead-Free Halide Double Perovskite Cs2AgInCl6 Nanocrystals.

Lead-free halide double perovskites (DPs) have been proposed as stable and promising alternatives to lead halide perovskites. Understanding the structural-optical properties of halide DPs is important for their applications. In this study, Cs2AgInCl6 DP nanocrystals, with a direct band gap, were synthesized and studied. Because of a strong electron-phonon coupling leading to exciton self-trapping, a broad emission with a large Stokes shift of Cs2AgInCl6 DP nanocrystals is observed. We observed an abnormal blue-shifted emission accompanied by a red-shifted direct absorption edge because of the reduced electron-phonon coupling under compression in the cubic phase Cs2AgInCl6 DP nanocrystals. Our study clarified the basic structural-optical correlation of halide DPs and may promote their application in related fields.

Retainable Superconductivity and Structural Transition in 1T-TaSe2 Under High Pressure.

As a prominent platform possessing the properties of superconductivity (SC) and charge density wave (CDW), transition-metal dichalcogenides (TMDCs) have attracted considerable attention for a long time. Moreover, extensive efforts have been devoted for exploring the SC and/or the interplay between SC and CDW in TMDCs in the past few decades. Here, we systematically investigate the electronic properties and structural evolution of 1T-TaSe2 under pressure. With increasing pressure, pressure-induced superconductivity is observed at ∼2.6 GPa. The superconductive transition temperature (Tc) increases with the suppression of the CDW state to the maximum value of ∼5.1 K at 21.8 GPa and then decreases monotonously up to the highest pressure of 57.8 GPa. 1T-TaSe2 transforms into a monoclinic C2/m structure above 19 GPa. The monoclinic phase coexists with the original phase as the pressure is released under ambient conditions and the retainable superconductivity with Tc = 2.9 K is observed in the released sample. We suggest that the retained superconductivity can be ascribed to the retention of the superconductive high-pressure monoclinic phase in the released sample. Our findings demonstrate that both the structure and CDW order are related to the superconductivity of TaSe2.

The extract of aquatic macrophyte Carex cinerascens induced colony formation in bloom-forming cyanobacterium Microcystis aeruginosa.

Colony formation in Microcystis aeruginosa played important roles in blooms formation. To study the effects of plant allelopathy on colony formation in M. aruginosa, unicellular M. aeruginosa was cultivated under laboratory conditions treated with various extract concentration of Carex cinerascens. The growth of M. aeruginosa in the treatments with 0.05 and 0.1 mg L-1 extract of C. cinerascens was promoted but the growth in the treatments with 1.5, 3.0, and 6.0 mg L-1 C. cinerascens extract was inhibited. Obvious colony formation in M. aeruginosa was observed in all treatments while no colony formation was detected in the control. The cell number per colony at the first day was the largest and decreased along with culture time. The cell number per colony in the control ranged from 3.0 to 4.0 during the experiment. However, the values in the five treatments at the first day were 33, 80, 58, 41, and 30, respectively. A positive exponential relationship between cell number per colony of M. aeruginosa and extracellular polysaccharides (EPS) content was found as well. Compared the fold-increase in cell number per colony and the fold-increase in total biomass of M. aeruginosa at various day, it was found that colony formation induced by extract of C. cinerascens was primarily dependent on promotion of cell adhesion during the first 2 days. The cell number per colony decreased afterward was due to the increasing proportion of single cells in the culture because single cells had a great higher growth rate than M. aeruginosa colonies under culture condition. Our results suggested that plant allelopathy be one of the major factor contributing to colony formation in M. aeruginosa.

One-Step Synthesis of Au-Ag Nanowires through Microorganism-Mediated, CTAB-Directed Approach.

Synthesis and applications of one dimensional (1D) metal nanostructures have attracted much attention. However, one-step synthesis of bimetallic nanowires (NWs) has remained challenging. In this work, we developed a microorganism-mediated, hexadecyltrimethylammonium bromide (CTAB)-directed (MCD) approach to synthesize closely packed and long Au-Ag NWs with the assistance of a continuous injection pump. Characterization results confirmed that the branched Au-Ag alloy NWs was polycrystalline. And the Au-Ag NWs exhibited a strong absorbance at around 1950 nm in the near-infrared (NIR) region, which can find potential application in NIR absorption. In addition, the Au-Ag NWs showed excellent surface-enhanced Raman scattering (SERS) enhancement when 4-mercaptobenzoic acid (MBA) and rhodamine 6G (R6G) were used as probe molecules.

[Effect of caring for chronic filariasis patients in Huaiyin District].

OBJECTIVE: To evaluate the effect of the caring for patients with lymphedema/chronic filariasis elephantiasis in Huaiyin District. METHODS: The chronic filariasis care sites were established and the medical workers provided the guidance regularly to patients for their self-cares. RESULTS: Through the caring for patients with chronic filariasis, their symptoms alleviated obviously, and the symptom frequency showed a significant downward trend. CONCLUSION: The caring for the chronic filariasis patients can alleviate the symptoms and improve the quality of life.