Thermally Activated Photoluminescence Induced by Tunable Interlayer Interactions in Naturally Occurring van der Waals Superlattice SnS/TiS2.

van der Waals (vdW) superlattices, comprising different 2D materials aligned alternately by weak interlayer interactions, offer versatile structures for the fabrication of novel semiconductor devices. Despite their potential, the precise control of optoelectronic properties with interlayer interactions remains challenging. Here, we investigate the discrepancies between the SnS/TiS2 superlattice (SnTiS3) and its subsystems by comprehensive characterization and DFT calculations. The disappearance of certain Raman modes suggests that the interactions alter the SnS subsystem structure. Specifically, such structural changes transform the band structure from indirect to direct band gap, causing a strong PL emission (∼2.18 eV) in SnTiS3. In addition, the modulation of the optoelectronic properties ultimately leads to the unique phenomenon of thermally activated photoluminescence. This phenomenon is attributed to the inhibition of charge transfer induced by tunable intralayer strains. Our findings extend the understanding of the mechanism of interlayer interactions in van der Waals superlattices and provide insights into the design of high-temperature optoelectronic devices.

A preliminary study unveils CISD2 as a ferroptosis-related therapeutic target for recurrent spontaneous abortion through immunological analysis and two-sample mendelian randomization.

Recurrent spontaneous abortion (RSA) affects approximately 1 % of women striving for conception, posing a significant clinical challenge. This study aimed to identify a prognostic signature in RSA and elucidate its molecular mechanisms. Prognostic gene impacts were further assessed in HTR-8/SVneo and human primary extravillous trophoblast (EVT) cells in vitro experiments. A total of 6168 differentially expressed genes (DEGs) were identified, including 3035 upregulated and 3133 downregulated genes. WGCNA pinpointed 8 significant modules and 31 ferroptosis-related DEGs in RSA. Optimal clustering classified RSA patients into three distinct subgroups, showing notable differences in immune cell composition. Six feature genes (AEBP2, CISD2, PML, RGS4, SRSF9, STK11) were identified. The diagnostic model showed high predictive capabilities (AUC: 0.966). Mendelian randomization indicated a significant association between CISD2 levels and RSA (OR: 1.069, P-value: 0.049). Furthermore, the downregulation of CISD2 promotes ferroptosis in HTR-8/SVneo and human primary EVT cells. CISD2 emerged as a pivotal gene in RSA, serving as a ferroptosis-related therapeutic target. The diagnostic model based on gene expression and Mendelian randomization provides novel insights into the pathogenesis of RSA.

Customizing precise, tunable, and universal cascade charge transfer chains towards versatile photoredox catalysis.

The core factors dictating the photocatalysis efficiency are predominantly centered on controllable modulation of anisotropic spatial charge transfer/separation and regulating vectorial charge transport pathways. Nonetheless, the sluggish charge transport kinetics and incapacity of precisely tuning interfacial charge flow at the nanoscale level are still the primary dilemma. Herein, we conceptually demonstrate the elaborate design of a cascade charge transport chain over transition metal chalcogenide-insulating polymer-cocatalyst (TIC) photosystems via a progressive self-assembly strategy. The intermediate ultrathin non-conjugated insulating polymer layer, i.e., poly(diallyl-dimethylammonium chloride) (PDDA), functions as the interfacial electron relay medium, and simultaneously, outermost co-catalysts serve as the terminal "electron reservoirs", synergistically contributing to the charge transport cascade pathway and substantially boosting the interfacial charge separation. We found that the insulating polymer mediated unidirectional charge transfer cascade is universal for a large variety of metal or non-metal reducing co-catalysts (Au, Ag, Pt, Ni, Co, Cu, NiSe2, CoSe2, and CuSe). More intriguingly, such peculiar charge flow characteristics endow the self-assembled TIC photosystems with versatile visible-light-driven photoredox catalysis towards photocatalytic hydrogen generation, anaerobic selective organic transformation, and CO2-to-fuel conversion. Our work would provide new inspiration for smartly mediating spatial vectorial charge transport towards emerging solar energy conversion.

Polaronic Nonlinear Optical Response and All-Optical Switching Based on an Ionic Metal Oxide.

It has been well-established that light-matter interactions, as manifested by diverse linear and nonlinear optical (NLO) processes, are mediated by real and virtual particles, such as electrons, phonons, and excitons. Polarons, often regarded as electrons dressed by phonons, are known to contribute to exotic behaviors of solids, from superconductivity to photocatalysis, while their role in materials' NLO response remains largely unexplored. Here, the NLO response mediated by polarons supported by a model ionic metal oxide, TiO2, is examined. It is observed that the formation of polaronic states within the bandgap results in a dramatic enhancement of NLO absorption coefficient by over 130 times for photon energies in the sub-bandgap regions, characterized by a 100 fs scale ultrafast response that is typical for thermalized electrons in metals. The ultrafast polaronic NLO response is then exploited for the development of all-optical switches for ultrafast pulse generation in near-infrared (NIR) fiber lasers and modulation of optical signal in the telecommunication band based on evanescent interaction on a planar waveguide chip. These results suggest that the polarons supported by dielectric ionic oxides can fill the gaps left by dielectric and metallic materials and serve as a novel platform for nonlinear photonic applications.

TGFA expression is associated with poor prognosis and promotes the development of cervical cancer.

Cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC) are the second most common cancers in women aged 20-39. While HPV screening can help with early detection of cervical cancer, many patients are already in the medium to late stages when they are identified. As a result, searching for novel biomarkers to predict CESC prognosis and propose molecular treatment targets is critical. TGFA is a polypeptide growth factor with a high affinity for the epidermal growth factor receptor. Several studies have shown that TGFA can improve cancer growth and progression, but data on its impact on the occurrence and advancement of CESC is limited. In this study, we used clinical data analysis and bioinformatics techniques to explore the relationship between TGFA and CESC. The results showed that TGFA was highly expressed in cervical cancer tissues and cells. TGFA knockdown can inhibit the proliferation, migration and invasion of cervical cancer cells. In addition, after TGFA knockout, the expression of IL family and MMP family proteins in CESC cell lines was significantly reduced. In conclusion, TGFA plays an important role in the occurrence and development of cervical cancer. Therefore, TGFA may become a new target for cervical cancer treatment.

Tailoring Broadband Nonlinear Optical Characteristics and Ultrafast Photocarrier Dynamics of Bi2 O2 S Nanosheets by Defect Engineering.

Low-dimensional bismuth oxychalcogenides have shown promising potential in optoelectronics due to their high stability, photoresponse, and carrier mobility. However, the relevant studies on deep understanding for Bi2 O2 S is quite limited. Here, comprehensive experimental and computational investigations are conducted in the regulated band structure, nonlinear optical (NLO) characteristics, and carrier dynamics of Bi2 O2 S nanosheets via defect engineering, taking O vacancy (OV) and substitutional Se doping as examples. As the OV continuously increased to ≈35%, the optical bandgaps progressively narrow from ≈1.21 to ≈0.81 eV and NLO wavelengths are extended to near-infrared regions with enhanced saturable absorption. Simultaneously, the relaxation processes are effectively accelerated from tens of picoseconds to several picoseconds, as the generated defect energy levels can serve as both additional absorption cross-sections and fast relaxation channels supported by theoretical calculations. Furthermore, substitutional Se doping in Bi2 O2 S nanosheets also modulate their optical properties with the similar trends. As a proof-of-concept, passively mode-locked pulsed lasers in the ≈1.0 µm based on the defect-rich samples (≈35% OV and ≈50% Se-doping) exhibit excellent performance. This work deepens the insight of defect functions on optical properties of Bi2 O2 S nanosheets and provides new avenues for designing advanced photonic devices based on low-dimensional bismuth oxychalcogenides.

Atrazine promotes breast cancer development by suppressing immune function and upregulating MMP expression.

There is evidence that the triazine herbicide atrazine, which is used extensively, is present in both surface water and groundwater, and its interfering effect on immune systems, endocrine systems, and tumours has been reported by laboratory and epidemiological studies. This study explored how atrazine affected 4T1 breast cancer cell development in vitro and in vivo. The obtained results showed that after exposure to atrazine, the cell proliferation and tumour volume were significantly increased and the expression of MMP2, MMP7, and MMP9 was upregulated. The thymus and spleen indices, the CD4 + and CD3 + lymphocyte percentages which from the spleen and inguinal lymph nodes, and the CD4 + /CD8 + ratio were noticeably lower than they were in the control group. Importantly, tumour-infiltrating lymphocytes such as CD4 + , CD8 + , and NK cells were decreased while Treg cells were increased. Moreover, IL-4 was increased and IFN-γ and TNF-α were decreased in the serum and tumour microenvironment. These results suggested that atrazine can suppress systemic as well as local tumour immune function and upregulate MMPs to promote breast tumour development.

Strain-Dependent Band Splitting and Spin-Flip Dynamics in Monolayer WS2.

Triggered by the expanding demands of semiconductor devices, strain engineering of two-dimensional transition metal dichalcogenides (TMDs) has garnered considerable research interest. Through steady-state measurements, strain has been proved in terms of its modulation of electronic energy bands and optoelectronic properties in TMDs. However, the influence of strain on the spin-orbit coupling as well as its related valley excitonic dynamics remains elusive. Here, we demonstrate the effect of strain on the excitonic dynamics of monolayer WS2 via steady-state fluorescence and transient absorption spectroscopy. Combined with theoretical calculations, we found that tensile strain can reduce the spin-splitting value of the conduction band and lead to transitions between different exciton states via spin-flip mechanism. Our findings suggest that the spin-flip process is strain-dependent, provides a reference for application of valleytronic devices, where tensile strain is usually existing during their design and fabrication.

Computational mining of GeH-based Janus III-VI van der Waals heterostructures for solar cell applications.

The asymmetrical group III-VI monolayer Janus M2XY (M = Al, Ga, In; X ≠ Y = S, Se, Te) have attracted widespread attention due to their significant optical absorption properties, which are the potential building blocks for van der Waals (vdW) heterostructure solar cells. In this study, we unraveled an In2STe/GeH vdW heterostructure as a candidate for solar cells by screening the Janus M2XY and GeH monolayers on lattice mismatches and electronic band structures based on first-principles calculations. The results highlight that the In2STe/GeH vdW heterostructure exhibits a type-II band gap of 1.25 eV. The optical absorption curve of the In2STe/GeH vdW heterostructure indicates that it possesses significant optical absorption properties in the visible and ultraviolet light areas. In addition, we demonstrate that the In2STe/GeH vdW heterostructure shows high and directionally anisotropic carrier mobility and good stability. Furthermore, strain engineering improves the theoretical power conversion efficiency of the In2STe/GeH vdW heterostructure up to 19.71%. Our present study will provide an idea for designing Janus M2XY and GeH monolayer-based vdW heterostructures for solar cell applications.

Novel Binary Ni-Based Mixed Metal-Organic Framework Nanosheets Materials and Their High Optical Power Limiting.

With the rapid advance of laser technology in the photonicera, damage to precision optical instruments caused by exposure to sudden intense laser pulses has stimulated the search for effective optical power limiting materials exhibiting good dispersion, fast response speed, and good visible light transparency. In this study, novel binary Ni-based mixed MOF NSs (M = Mn, Zn, Co, Cd, Fe) were obtained, making the electronic transition more selective and changing the band gap to obtain an excellent reverse saturation absorption signal. The theoretical calculation results show that with the doping of the Fe element, the band gap of Ni-MOF NSs decreases from 3.12 to 0.66 eV of Ni-Fe-MOF NSs, indicating that the doping of the Fe element has a positive effect on the reverse saturated absorption. The experimental results prove that the optical limiting threshold of Ni-Fe-MOF NSs is better than the GNSs, indicating that the Ni-Fe-MOF NSs have a broad application prospect in the field of nonlinear optics and photonics.

Aptamer Nanomaterials for Ovarian Cancer Target Theranostics.

Ovarian cancer is among the leading causes of gynecological cancer-related mortality worldwide. Early and accurate diagnosis and an effective treatment strategy are the two primary means of improving the prognosis of patients with ovarian cancer. The development of targeted nanomaterials provides a potentially efficient strategy for ovarian cancer theranostics. Aptamer nanomaterials have emerged as promising nanoplatforms for accurate ovarian cancer diagnosis by recognizing relevant biomarkers in the serum and/or on the surface of tumor cells, as well as for effective ovarian cancer inhibition via target protein blockade on tumor cells and targeted delivery of various therapeutic agents. In this review, we summarize recent advances in aptamer nanomaterials as targeted theranostic platforms for ovarian cancer and discusses the challenges and opportunities for their clinical application. The information presented in this review represents a valuable reference for creation of a new generation of aptamer nanomaterials for use in the precise detection and treatment of ovarian cancer.

Defect-Rich Monolayer MoS2 as a Universally Enhanced Substrate for Surface-Enhanced Raman Scattering.

Monolayer 2H-MoS2 has been widely noticed as a typical transition metal dichalcogenides (TMDC) for surface-enhanced Raman scattering (SERS). However, monolayer MoS2 is limited to a narrow range of applications due to poor detection sensitivity caused by the combination of a lower density of states (DOS) near the Fermi energy level as well as a rich fluorescence background. Here, surfaced S and Mo atomic defects are fabricated on a monolayer MoS2 with a perfect lattice. Defects exhibit metallic properties. The presence of defects enhances the interaction between MoS2 and the detection molecule, and it increases the probability of photoinduced charge transfer (PICT), resulting in a significant improvement of Raman enhancement. Defect-containing monolayer MoS2 enables the fluorescence signal of many dyes to be effectively burst, making the SERS spectrum clearer and making the limits of detection (LODs) below 10-8 M. In conclusion, metallic defect-containing monolayer MoS2 becomes a promising and versatile substrate capable of detecting a wide range of dye molecules due to its abundant DOS and effective PICT resonance. In addition, the synergistic effect of surface defects and of the MoS2 main body presents a new perspective for plasma-free SERS based on the chemical mechanism (CM), which provides promising theoretical support for other TMDC studies.

Layer-Tunable Nonlinear Optical Characteristics and Photocarrier Dynamics of 2D PdSe2 in Broadband Spectra.

Layered 2D transition metal dichalcogenides (TMDCs) exhibited fascinating nonlinear optical (NLO) properties for constructing varied promising optoelectronics. However, exploring the desired 2D materials with both superior nonlinear absorption and ultrafast response in broadband spectra remain the key challenges to harvest their greatest potential. Here, based on synthesizing 2D PdSe2 films with the controlled layer number, the authors systematically demonstrated the broadband giant NLO performance and ultrafast excited carrier dynamics of this emerging material under femtosecond visible-to-near-infrared laser-pulse excitation (400-1550 nm). Layer-dependent and wavelength-dependent evolution of optical bandgap, nonlinear absorption, and photocarrier dynamics in the obtained 2D PdSe2 are clearly revealed. Specially, the transition from semiconducting to semimetallic PdSe2 induced dramatic changes of their interband absorption-relaxation process. This work makes 2D PdSe2 more competitive for future ultrafast photonics and also opens up a new avenue for the optical performance optimization of various 2D materials by rational design of these materials.

Circular RNA: A potential diagnostic, prognostic, and therapeutic biomarker for human triple-negative breast cancer.

Triple-negative breast cancer (TNBC), which is the most malignant subtype of breast cancer (BC), accounts for 10%-20% of all BC cases. TNBC, which occurs more frequently in young women, is characterized by high rates of cell proliferation and metastasis and poor prognosis. Chemotherapy is the primary systemic therapeutic strategy for TNBC. However, chemotherapy is largely unsuccessful, and effective targeted therapies for TNBC have not been established. Therefore, it is a matter of great urgency to identify precise molecular targets for the promising prognosis of patients with TNBC. Circular RNAs (circRNAs), which are a type of non-coding RNAs (ncRNAs), are abundantly expressed in the eukaryotic cells and exhibit diverse cellular functions. The roles of circRNAs are to sponge microRNA or RNA-binding proteins, regulate gene expression, and serve as templates for translation. Here, we review the current findings on the potential of circRNAs as a diagnostic, prognostic, and therapeutic biomarker for TNBC. However, further studies are essential to elucidate the functions of circRNAs in TNBC. This review also discusses the current limitations and future directions of TNBC-associated circRNAs, which can facilitate the translation of experimental research into clinical application.

Chemical Synthesis and Integration of Highly Conductive PdTe2 with Low-Dimensional Semiconductors for p-Type Transistors with Low Contact Barriers.

Low-dimensional semiconductors provide promising ultrathin channels for constructing more-than-Moore devices. However, the prominent contact barriers at the semiconductor-metal electrodes interfaces greatly limit the performance of the obtained devices. Here, a chemical approach is developed for the construction of p-type field-effect transistors (FETs) with low contact barriers by achieving the simultaneous synthesis and integration of 2D PdTe2 with various low-dimensional semiconductors. The 2D PdTe2 synthesized through a quasi-liquid process exhibits high electrical conductivity (≈4.3 × 106 S m-1 ) and thermal conductivity (≈130 W m-1 K-1 ), superior to other transition metal dichalcogenides (TMDCs) and even higher than some metals. In addition, PdTe2 electrodes with desired geometry can be synthesized directly on 2D MoTe2 and other semiconductors to form high-performance p-type FETs without any further treatment. The chemically derived atomically ordered PdTe2 -MoTe2 interface results in significantly reduced contact barrier (65 vs 240 meV) and thus increases the performance of the obtained devices. This work demonstrates the great potential of 2D PdTe2 as contact materials and also opens up a new avenue for the future device fabrication through the chemical construction and integration of 2D components.

Hierarchical Nanoreactor with Multiple Adsorption and Catalytic Sites for Robust Lithium-Sulfur Batteries.

Developing high-performance cathode host materials is fundamental to solve the low utilization of sulfur, the sluggish redox kinetics, and the lithium polysulfide (LiPS) shuttle effect in lithium-sulfur batteries (LSBs). Here, a multifunctional Ag/VN@Co/NCNT nanocomposite with multiple adsorption and catalytic sites within hierarchical nanoreactors is reported as a robust sulfur host for LSB cathodes. In this hierarchical nanoreactor, heterostructured Ag/VN nanorods serve as a highly conductive backbone structure and provide internal catalytic and adsorption sites for LiPS conversion. Interconnected nitrogen-doped carbon nanotubes (NCNTs), in situ grown from the Ag/VN surface, greatly improve the overall specific surface area for sulfur dispersion and accommodate volume changes in the reaction process. Owing to their high LiPS adsorption ability, outer Co nanoparticles at the top of the NCNTs catch escaped LiPS, thus effectively suppressing the shuttle effect and enhancing kinetics. Benefiting from the multiple adsorption and catalytic sites of the developed hierarchical nanoreactors, Ag/VN@Co/NCNTs@S cathodes display outstanding electrochemical performances, including a superior rate performance of 609.7 mAh g-1 at 4 C and a good stability with a capacity decay of 0.018% per cycle after 2000 cycles at 2 C. These properties demonstrate the exceptional potential of Ag/VN@Co/NCNTs@S nanocomposites and approach LSBs closer to their real-world application.

Rapid and Large-Scale Quality Assessment of Two-Dimensional MoS2 Using Sulfur Particles with Optical Visualization.

The efficient nondestructive assessment of quality and homogeneity for two-dimensional (2D) MoS2 is critically important to advance their practical applications. Here, we presented a rapid and large-area assessment method for visually evaluating the quality and uniformity of chemical vapor deposition (CVD)-grown MoS2 monolayers simply with conventional optical microscopes. This was achieved through one-pot adsorbing abundant sulfur particles selectively onto as-grown poorer-quality MoS2 monolayers in a CVD system without any additional treatment. We further revealed that this favorable adsorption of sulfur particles on MoS2 originated from their intrinsic higher-density sulfur vacancies. Based on unadsorbed MoS2 monolayers, superior performance field effect transistors with a mobility of ∼49 cm2 V-1 s-1 were constructed. Importantly, the assessment approach was noninvasive due to the all-vapor-phase and moderate adsorption-desorption process. Our work offers a new route for the performance and yield optimization of devices by quality assessment of 2D semiconductors prior to device fabrication.

Elastic Anisotropy and Optic Isotropy in Black Phosphorene/Transition-Metal Trisulfide van der Waals Heterostructures.

Anisotropic two-dimensional materials with direction-dependent mechanical and optical properties have attracted significant attention in recent years. In this work, based on density functional theory calculations, unexpected elastic anisotropy and optical isotropy in van der Waals (vdW) heterostructures have been theoretically proposed by assembling the well-known anisotropic black phosphorene (BP) and transition-metal trisulfides MS3 (M = Ti, Hf) together. It is interesting to see that the BP/MS3 vdW heterostructures show anisotropic flexibility in different directions according to the elastic constants, Young's modulus, and Poisson's ratio. We have further unraveled their physical origin of the type-II band structure nature with their conduction band minimum and valence band maximum separated in different layers. In particular, our results on the optical response functions including the excitonic effects of the BP/MS3 vdW heterostructures suggest their unexpected optical isotropies together with the enhancements of the solar energy conversion efficiency.

Unveiling the Layer-Dependent Catalytic Activity of PtSe2 Atomic Crystals for the Hydrogen Evolution Reaction.

Two-dimensional (2D) PtSe2 shows the most prominent layer-dependent electrical properties among various 2D materials and high catalytic activity for hydrogen evolution reaction (HER), and therefore, it is an ideal material for exploring the structure-activity correlations in 2D systems. Here, starting with the synthesis of single-crystalline 2D PtSe2 with a controlled number of layers and probing the HER catalytic activity of individual flakes in micro electrochemical cells, we investigated the layer-dependent HER catalytic activity of 2D PtSe2 from both theoretical and experimental perspectives. We clearly demonstrated how the number of layers affects the number of active sites, the electronic structures, and electrical properties of 2D PtSe2 flakes and thus alters their catalytic performance for HER. Our results also highlight the importance of efficient electron transfer in achieving optimum activity for ultrathin electrocatalysts. Our studies greatly enrich our understanding of the structure-activity correlations for 2D catalysts and provide new insight for the design and synthesis of ultrathin catalysts with high activity.

Author Correction: Probing the crystallographic orientation of two-dimensional atomic crystals with supramolecular self-assembly.

The original version of this Article omitted the following from the Acknowledgements: 'Beijing Municipal Science & Technology Commission (No Z161100002116030)' This has now been corrected in both the PDF and HTML versions of the Article.