Interlayer Coherent Dipole-Dipole Coupling Facilitates Charge Transfer in Multilayer Transition Metal Dichalcogenide Heterostructures.

Inserting intermediate layers in transition metal dichalcogenide heterostructures (TMD HSs) has become an efficient approach to modulating interlayer charge transfer rates. However, it could not only modify the distance of charge transfer but also potentially alter the interlayer coupling strength within HSs, which would profoundly influence the charge transfer rate in the opposite direction. Here, to gain insight into the dual roles of inserted intermediate layers in multilayer TMD HSs, MoS-L WSe-MoSe ( = 1-3) HSs were designed and systemically investigated.

Chiral Perovskite Heterostructure Films of CsPbBr Quantum Dots and 2D Chiral Perovskite with Circularly Polarized Luminescence Performance and Energy Transfer.

This work reports the synthesis of chiral perovskite heterostructure films by combining a two-dimensional (2D) chiral (R-/S-MBA)PbI perovskite with CsPbBr quantum dots (QDs). The as-synthesized chiral heterostructure films exhibit obvious circularly polarized luminescence (CPL) properties, even though pure 2D chiral perovskite cannot present photoluminescence. It indicates that the chirality of the excited state of the QDs originates from the 2D chiral perovskite.

Dynamic Ultrastrong Coupling in a 2 nm Gap Plasmonic Cavity at the Sub-Picosecond Scale.

Localized surface plasmon resonances (LSPRs) can enhance the electromagnetic fields on metallic nanostructures upon light illumination, providing an approach for manipulating light-matter interactions at the sub-wavelength scale. However, currently, there is no thorough investigation of the physical mechanism in the dynamic formation of the strongly coupled LSPRs on sub-5 nm plasmonic cavities at the sub-picosecond scale. In this work, through femtosecond broadband transient absorption spectroscopy, we reveal the dynamic ultrastrong coupling processes in a nanoparticle-in-trench (NPiT) structure containing 2 nm gap cavities, and demonstrate a coherent motional coupling between vibrating AuNPs and the nanogaps.

Excitonic Effect Drives Ultrafast Transition in Two-Dimensional Transition Metal Dichalcogenides.

Two-dimensional (2D) transition metal dichalcogenides (TMDCs) are ideal platforms for exploring excitonic physics because of the tightly bound excitons. In this work, we observed the onset of band-edge exciton formation in monolayer MoS (WS) and bilayer MoS-WS by measuring the transient optical response upon excitation with ultrashort laser pulses. In addition to wavelength dependence on excitation under nonresonant excitation, we found that the onset of band-edge exciton formation in monolayer MoS (WS) pumped in the exciton state is significantly faster than that with pumping in the nonexciton state, which could be attributed to the effective transition between exciton states induced by the excitonic effect.

Feasibility analysis of CT-guided thermal ablation of multiple pulmonary nodules combined with intraoperative biopsy.

Purpose: To analyze the safety and feasibility of computed tomography (CT)-guided thermal ablation of multiple pulmonary nodules combined with intraoperative biopsy.

Methods: The data of 431 patients with 540 lung nodules undergoing CT-guided biopsy or ablation were retrospectively analyzed. Biopsy-only group (A): 107 patients (107 lesions) received CT-guided percutaneous lung biopsy only; Ablation-only group (B): 117 cases (117 lesions) only received CT-guided thermal ablation; Single focal ablation combined with biopsy group (C): 103 patients (103 lesions) received CT-guided thermal ablation combined with intraoperative immediate biopsy; Multifocal ablation combined with biopsy group (D): 104 patients (213 lesions) received CT-guided thermal ablation combined with intraoperative biopsy.

The Role of Polaronic States on the Spin Dynamics in Solution-Processed Two-Dimensional Layered Perovskite with Different Layer Thickness.

2D lead halide perovskites (LHPs) show strong excitonic and spin-orbit coupling effects, generating a facile spin injection. Besides, they possess a polaron character due to the soft crystal lattice, which can prolong the spin lifetime, making them favorable materials for spintronic applications. Here, the spin dynamics of 2D PEA PbI (MAPbI ) thin films with different layers by temperature- and pump fluence-dependent circularly polarization-resolved transient absorption (TA) measurements is studied.

Tailoring photoluminescence of WS-microcavity coupling devices in broad visible range.

Most of the previous TMDC-photon coupling devices were mainly based on A exciton due to its high oscillator strength and large exciton binding energy. Less effort has been focused on the modulation of the emission of B exciton and Rydberg states in TMDCs, especially in monolayer WS. Here, we demonstrate that the photoluminescence (PL) emission of WS-microcavity coupling devices can be tailored in a broad visible wavelength range (490 nm-720 nm).

The latest research progress on minimally invasive treatments for hepatocellular carcinoma.

Background: Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related death worldwide. Due to the high prevalence of hepatitis B virus (HBV) infection in China, the incidence of HCC in China is high, and liver cirrhosis caused by chronic hepatitis also brings great challenges to treatment. This paper reviewed the latest research progress on minimally invasive treatments for HCC, including percutaneous thermal ablation and new nonthermal ablation techniques, and introduced the principles, advantages, and clinical applications of various therapeutic methods in detail.

Ultrafast dynamics of spin relaxation in monolayer WSe and the WSe/graphene heterojunction.

Excitonic devices based on two-dimensional (2D) transition metal dichalcogenides (TMDCs) can combine spintronics with valleytronics due to its special energy band structure. In this work, we studied the generation and relaxation processes of spin/valley polarized excitons dynamics in monolayer WSe and its van der Waals (vdW) heterojunction with graphene using a circularly polarized femtosecond pump-probe system. The spin/valley depolarization dynamics of the A exciton in monolayer WSe is found to exhibit a biexponential decay.

Spin-Valley Depolarization in van der Waals Heterostructures.

The appearance of van der Waals heterostructures offers a new solution to valleytronics. Here, we observe the spin-valley depolarization process of electrons and holes in type-II MoS-WSe heterostructures simultaneously for the first time by valley-resolved broad-band femtosecond pump-probe experiments. The different depolarization paths between electrons and holes make them have different spin-valley polarization lifetimes.

Exciton-Phonon Coupling of Chiral One-Dimensional Lead-Free Hybrid Metal Halides at Room Temperature.

The interaction between organic cations and inorganic metal halide octahedral units strongly affects the properties of organic-inorganic hybrid metal halides. The "soft" property of the lattice provides the possibility of its strong exciton-phonon interaction. Here we report one-dimensional (1D) lead-free chiral organic-inorganic hybrid metal halide single crystals of (/)-methylbenzylamine bismuth iodide (/-MBA)BiI, which exhibits a high level of octahedral bond distortion.

Ultrasonic spleen thickness-based indexes surpass Baveno VI criteria in high-risk gastroesophageal varices detection.

Aims: To evaluate the efficiency of ultrasonic spleen thickness (UST), routine variables and (expanded) Baveno VI criteria for high-risk gastroesophageal varices (HRGOV) detection in cirrhotic patients.

Methods: In total, 305 cirrhotic patients were retrospectively enrolled in the deriving cohort and 328 cirrhotic patients with hepatitis B sustained viral response were prospectively enrolled in the validation cohort. HRGOV was defined as medium and severe gastroesophageal varices (GOV), mild GOV with red signs or Child-Pugh C.

Klf4 methylated by Prmt1 restrains the commitment of primitive endoderm.

The second cell fate decision in the early stage of mammalian embryonic development is pivotal; however, the underlying molecular mechanism is largely unexplored. Here, we report that Prmt1 acts as an important regulator in primitive endoderm (PrE) formation. First, Prmt1 depletion promotes PrE gene expression in mouse embryonic stem cells (ESCs).

Observation of quantum-confined exciton states in monolayer WS quantum dots by ultrafast spectroscopy.

Monolayer transition metal dichalcogenide quantum dots (TMDC QDs) could exhibit unique photophysical properties, because of both lateral quantum confinement effect and edge effect. However, there is little fundamental study on the quantum-confined exciton dynamics in monolayer TMDC QDs, to date. Here, by selective excitations of monolayer WS QDs in broadband transient absorption (TA) spectroscopy experiments, the excitation-wavelength-dependent ground state bleaching signals corresponding to the quantum-confined exciton states are directly observed.

Trion dynamics and charge photogeneration in MoS nanosheets prepared by liquid phase exfoliation.

Since excitonic quasiparticles, including excitons, trions and charges, have a great influence on the photoelectric characteristics of two-dimensional (2D) transition metal dichalcogenides (TMDs), systematic explorations of the trion dynamics and charge photogeneration in 2D TMDs are important for their future optoelectronic applications. Here, broadband femtosecond transient absorption spectroscopic experiments are performed first to investigate the peak shifting and broadening kinetics in MoS nanosheets in solution prepared by liquid phase exfoliation (LPE-MoS, ∼9 layers, 9L), which reveal that the binding energies for the A-, B-, and C-exciton states are ∼77 meV, ∼76 meV, and -70 meV (the energy difference between free charges and excitons; the negative sign for C-excitons means a spontaneous dissociation nature in band-nesting regions), respectively. Then, the trion dynamics and charge photogeneration in LPE-MoS nanosheets have been studied in detail, demonstrating that they are comparable to those in chemical vapor deposition grown MoS films (1L-, 3L- and 7L-MoS).

Observation of robust charge transfer under strain engineering in two-dimensional MoS-WSe heterostructures.

Strain is one of the effective ways to modulate the band structure of monolayer transition metal dichalcogenides (TMDCs), which has been reported in theoretical and steady-state spectroscopic studies. However, the strain effects on the charge transfer processes in TMDC heterostructures have not been experimentally addressed thus far. Here, we systematically investigate the strain-mediated transient spectral evolutions corresponding to excitons at band-edge and higher energy states for monolayer MoS and monolayer WSe.

A novel multichromic Zn(II) cationic coordination polymer based on a new flexible viologen ligand exhibiting aniline detection in the solid state.

In this work, a novel multichromic cationic coordination polymer, named [Zn4(BTC)3(bcbpy)2]·5H2O (1), based on a new flexible viologen ligand 1,1'-bis(3-cyanobenzyl)-[4,4'-bipyridine]-1,1'-diium (H2bcbpy·2Cl), Zn(NO3)2·6H2O and pyromellitic acid (H4BTC) was synthesized. Compound 1 has good photosensitive activity and can respond to sunlight at room temperature. The colour of compound 1 changes rapidly in response to UV light and blue ray irradiation within 5 s.

Sequence Variations of Epstein-Barr Virus-Encoded Small Noncoding RNA and Latent Membrane Protein 1 in Hematologic Tumors in Northern China.

Objective: To investigate the relationship between hematologic tumors and Epstein-Barr virus (EBV)-encoded small noncoding RNA (EBER) variations as well as latent membrane protein 1 (LMP1) variations.

Methods: Patients with leukemia and myelodysplastic syndrome (MDS) were selected as subjects. Genotypes 1/2 and genotypes F/f were analyzed using the nested PCR technology, while EBER and LMP1 subtypes were analyzed by the nested PCR and DNA sequencing.

Many-particle induced band renormalization processes in few- and mono-layer MoS.

Band renormalization effects play a significant role for two-dimensional (2D) materials in designing a device structure and customizing their optoelectronic performance. However, the intrinsic physical mechanism about the influence of these effects cannot be revealed by general steady-state studies. Here, band renormalization effects in organic superacid treated monolayer MoS, untreated monolayer MoSand few-layer MoSare quantitatively analyzed by using broadband femtosecond transient absorption spectroscopy.

Transient Depolarization Spectroscopic Study on Electronic Structure and Fluorescence Origin of Graphene Oxide.

It is well-established that the electronic states of graphene oxide (GO) consist of sp clusters with different sizes and the surrounding sp matrix according to recent reports. However, addressing the excitation energy migration/redistribution among those electronic states in GO-based complex systems from spectroscopic experiments is still a challenge. Here, we combine the time-resolved absorption and fluorescence depolarization experiments to reveal the excitation energy migration processes in electronic states in GO.

A novel photochromic coordination polymer based on a robust viologen ligand exhibiting multiple detection properties in the solid state.

A new photochromic and porous Cd(ii) coordination polymer (CP) has been synthesized by using a robust viologen ligand, named 1-(3-carboxybenzyl)-4,4'-bipyridinium chloride (m-Hbcbpy·Cl) and CdCl·2HO. This CP (Cd-bcbpy) shows a fast response and reversible photochromism through the progress of ET due to the formation of viologen radicals. Cd-bcbpy shows a sharp response to blue rays and selectively detects organic amine molecules, which are electron rich, in the solid state due to the electron-deficient properties of m-Hbcbpy·Cl.