Highly Selective Pb(II) Adsorption by DTPA-Functionalized Graphene Oxide/Carboxymethyl Cellulose Aerogel.

Graphene oxide (GO) exhibits a strong adsorption capacity for the removal of heavy metal ions from liquids, making it a topic of increasing interest among researchers. However, a significant challenge persists in the preparation of graphene oxide-based adsorbents that possess both high structural stability and excellent adsorption capacity. In this paper, a green and environmentally friendly ternary composite aerogel based on graphene was successfully synthesized. The adsorption capacity of graphene oxide was enhanced through diethylenetriaminepentaacetic acid modification, while the incorporation of composite carboxymethyl cellulose improved the structural stability of the composite aerogel in liquid. The composite aerogel demonstrates robust interactions between its components and features a multiscale porous structure. Adsorption tests conducted with Pb(II) revealed that the GO/DTPA/CMC (GDC) composite aerogel exhibits a favorable adsorption capacity. The study of adsorption kinetics and isotherms indicated that the adsorption process follows the quasi-secondary adsorption model and Freundlich adsorption model, suggesting a chemical multilayer adsorption mechanism, and the maximum adsorption capacity for Pb(II) ions was 521.917 mg/g based on the quasi-quadratic kinetic model fitting. X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) analyses, performed before and after adsorption, confirmed that the adsorption of Pb(II) primarily occurs through chelation, complexation, proton exchange, and electrostatic interactions between ions and active sites such as hydroxyl and carboxyl groups. This study presents an innovative strategy for simultaneously enhancing the adsorption properties of graphene oxide-based composite aerogels and ensuring solution stability.

Effects of strain and thickness on the mechanical, electronic, and optical properties of Cu2Te.

Two-dimensional transition-metal chalcogenides (TMCs) have attracted considerable attention because of their exceptional photoelectric properties, finding applications in diverse fields such as photovoltaics, lithium-ion batteries, catalysis, and energy conversion and storage. Recently, experimentally fabricated monolayers of semiconducting Cu2Te have emerged as intriguing materials with outstanding thermal and photoelectric characteristics. In this study, we employ first-principles calculations to investigate the mechanical, electronic, and optical properties of monolayer Cu2Te exhibiting both λ and ζ structures, considering the effects of thickness and strain. The calculations reveal the robust mechanical stability of λ-Cu2Te and ζ-Cu2Te under varying thickness and strain conditions. By applying -5% to +5% strain, the band gaps can be modulated, with ζ-Cu2Te exhibiting an indirect-to-direct transition at a biaxial strain of +5%. In addition, a semiconductor-to-metal transition is observed for both ζ-Cu2Te and λ-Cu2Te with increasing thickness. The absorption spectra of λ-Cu2Te and ζ-Cu2Te exhibit a redshift with an increase in the number of layers. These computational insights into Cu2Te provide valuable information for potential applications in nano-electromechanical systems, optoelectronics, and photocatalytic devices and may guide subsequent experimental research efforts.

Modulation of supramolecular structure by stepwise removal of tert-butyl groups from tetraazaperopyrene derivatives on Ag(111).

Tert-butyl functional groups can modulate the self-assembly behavior of organic molecules on surfaces. However, the precise construction of supramolecular architectures through their controlled thermal removal remains a challenge. Herein, we precisely controlled the removal amount of tert-butyl groups in tetraazaperopyrene derivatives by stepwise annealing on Ag(111). The evolution of 4tBu-TAPP supramolecular self-assembly from the grid-like structure composed of 3tBu-TAPP through the honeycomb network formed by 2tBu-TAPP to the one-dimensional chain co-assembled by tBu-TAPP and TAPP was successfully realized. This series of supramolecular nanostructures were directly visualized by high resolution scanning tunneling microscopy. Tip manipulation and density functional theory calculations show that the formation of honeycomb network structure can be attributed to the van der Waals interactions, N-Ag-N coordination bonds, and weak C-H⋯N hydrogen bonds. Further addition of two tert-butyl groups (6tBu-TAPP) leads to a completely different assembly evolution, due to the fact that the additional tert-butyl groups affect the molecular adsorption behavior and ultimately induce desorption. This work can possibly be exploited in constructing stable and long-range ordered nanostructures in surface-assisted systems, which can also promote the development of nanostructures in functional molecular devices.

Boosting the Cell Performance of the SiO/Cu and SiO/PPy Anodes via In-Situ Reduction/Oxidation Coating Strategies.

Silicon monoxide (SiO) has attracted great attention due to its high theoretical specific capacity as an alternative material for conventional graphite anode, but its poor electrical conductivity and irreversible side reactions at the SiO/electrolyte interface seriously reduce its cycling stability. Here, to overcome the drawbacks, the dicharged SiO anode coated with Cu coating layer is elaborately designed by in-situ reduction method. Compared with the pristine SiO anode of lithium-ion battery (293 mAh g-1 at 0.5 A g-1 after 200 cycles), the obtained SiO/Cu composite presents superior cycling stability (1206 mAh g-1 at 0.5 A g-1 after 200 cycles). The tight combination of Cu particles and SiO significantly improves the conductivity of the composite, effectively inhibits the side-reaction between the active material and electrolyte. In addition, polypyrrole-coated SiO composites are further prepared by in-situ oxidation method, which delivers a high reversible specific capacity of 1311 mAh g-1 at 0.5 A g-1 after 200 cycles. The in-situ coating strategies in this work provide a new pathway for the development and practical application of high-performance silicon-based anode.

High Photocatalytic Hydrogen Production of Ag@TiO2 with Different Sizes by Simple Chemical Synthesis.

The photocatalytic enhancement of sliver-based metals compounded with semiconductor materials has been demonstrated. However, there are relatively few studies on the effect of particle size in the system on photocatalytic performance. In this paper, silver nanoparticles of two different sizes, 25 and 50 nm, were prepared by a wet chemical method and subsequently sintered to obtain a photocatalyst with a core-shell structure. The photocatalyst Ag@TiO2-50/150 prepared in this study has a hydrogen evolution rate as high as 4538.90 µmol·g-1·h-1. It is interesting to find that when the ratio of silver core size to composite size is 1:3, the hydrogen yield is almost not affected by the silver core diameter, and the hydrogen production rate is basically the same. In addition, the rate of hydrogen precipitation in air for 9 months was still more than 9 times those of previous studies. This provides a new idea for the study of the oxidation resistance and stability of photocatalysts.

Adsorption configurations and electronic properties of self-assembled C60and C70molecules on a semiconductor CuSe monolayer with periodic nanopores.

Two-dimensional (2D) supramolecular self-assembly architectures are considered one of the most significant and challenging topics in nanotechnology and modern organic chemistry. The study of these processes on surfaces is vital to achieving a higher degree of control in the design of supramolecular architecture. Herein, we report on the 2D self-assembly monolayer architectures based on C60and C70molecules on a semiconductor CuSe monolayer with periodic nanopores, which are essential for providing ideas for surface template chemistry. With the aid of low-temperature scanning tunneling microscopy/spectroscopy (LT-STM/STS) and density functional theory (DFT) calculation methods, we systematically investigate the adsorption configurations and electronic properties of C60and C70on CuSe monolayer with periodic nanopores. Our results show that both the C60and C70molecules above the nanopores will fall into the nanopores, while those on the CuSe surface will show well-defined self-assembly with various adsorption configurations. Besides, through STS measurement, the lowest unoccupied molecular orbitals (LUMOs) and characteristic peaks of fullerene molecules will be slightly different due to different adsorption configurations. This work helps us to study the adsorption behavior of the fullerene family on various kinds of semiconductor substrates, and also provides vigorous support for the development of fullerene electrical devices in the future.

A family of robust Dirac cone materials: two-dimensional hexagonal M3X2 (M = Zn/Cd/Hg, X = Si/Ge).

The fascinating Dirac cone, which has produced some excellent properties in graphene, such as ballistic charge transport, ultra-high carrier mobility and the quantum Hall effect, has motivated researchers to design and study more two dimensional (2D) Dirac materials. In this work, we have designed a family of 2D Dirac cone materials M3X2 (M = Zn/Cd/Hg, X = Si/Ge) and studied their superior properties by first principles calculation. The calculated cohesive energy, phonon dispersion and ab initio molecular dynamics confirmed the energetic, dynamic and thermodynamic stability of Zn3Ge2, Cd3Ge2, Hg3Si2, and Cd3Si2 monolayers. It was found that the intrinsic Dirac cones exist in the electronic structure of the Zn3Ge2, Cd3Ge2, Hg3Si2 and Cd3Si2 monolayers. Their Fermi velocities are from 3.26 × 105 m s-1 to 4.32 × 105 m s-1 (8.2 × 105 m s-1 for graphene). It is noteworthy that the Dirac cone in the M3X2 structure is robust. It is independent of external strain (from -7% to +19%) and can also be preserved as one-dimensional zigzag nanoribbons and multilayers (from two to three-layers). Our work shows that the novel M3X2 Dirac cone materials are an important candidate for high-speed nanoelectronic devices.

The versatile characteristics of Ars/SGaInS van der Waals heterostructures.

Two-dimensional (2D) materials with upright stacking form layered van der Waals heterostructures (vdWHs) are currently believed to be attractive prospects for optoelectronic, photocatalytic, and thermoelectric devices because they can merge the capabilities of distinct 2D materials. Herein, we evaluate the electronic, optical, photocatalytic, and thermoelectric response of model-I and model-II of Ars/SGaInS vdWHs via first-principles computations. The energetic, dynamical, and thermal stabilities of these vdWHs suggest great promise in experimental functionality. Model-I and model-II are indirect semiconductors with type-II band alignment and bandgaps of 1.53 eV and 1.86 eV, respectively. The built-in electric field considerably accelerates the transmission of electrons from the Ars layer to the SGaInS layer. Compared to pristine monolayers, both models contain appropriate band edge positions to ensure overall water splitting efficiently. Interestingly, at -8% compressive strain, model-I secures type-III band alignment, which is very advantageous for field-effect transistors. In the visible and ultraviolet zones of the radiating spectrum, the proposed vdWHs significantly improved the absorption spectra, and the biaxial strain also has a considerable impact on optical absorption. The investigated vdWHs have high Seebeck coefficients and substantial electrical conductivities, which contribute to high power factor values, particularly at 700 K. The outcomes specify that our designed Ars/SGaInS vdWHs have a multifunctional character that can perform a better role in optoelectronics, photovoltaics, photocatalysis, tunneling field effect transistors, and thermoelectric devices.

Study on the mechanism of NOx reduction by NH3-SCR over a ZnXCu1-XFe2O4 catalyst.

Experimental evidence shows that CuFe2O4 exhibits excellent catalytic performance in the SCR reaction. However, there is a lack of in-depth research on its specific reaction mechanism. Our study begins by computing the adsorption model of molecules like NH3 and then goes on to examine the SCR reaction mechanism of NH3 on CuFe2O4 before and after Zn doping. The results indicate that NH3 is chemically adsorbed (-1.26 eV) on the surface and has a strong interaction with the substrate. Importantly, Zn doping provides more favorable reactive sites for NH3 molecules. Subsequent investigation into the NH3 dehydrogenation and SCR reaction processes showed that incorporating Zn can greatly decrease the energy barrier of the most critical step in the reaction (0.58 eV). Additionally, the study also assesses the feasibility of the reaction of adsorbed NO with surface active O atoms to form NO2 (barrier 0.86 eV). Lastly, the sulfur resistance of the catalyst before and after doping is calculated and analyzed, and it is found that Zn doping effectively improves the sulfur resistance. Our study provides valuable theoretical guidance for the development of ferrite spinel and doping modification.

On-surface synthesis of Au-C4 and Au-O4 alternately arranged organometallic coordination networks via selective aromatic C-H bond activation.

Selective activation of the C-H bond of aromatic hydrocarbons is significant in synthetic chemistry. However, achieving oriented C-H activation remains challenging due to the poor selectivity of aromatic C-H bonds. Herein, we successfully constructed alternately arranged Au-C4 and Au-O4 organometallic coordination networks through selective aromatic C-H bond activation on Au(111) substrate. The stepwise reaction process of the 5, 12-dibromopyrene 3,4,9, 10-tetracarboxylic dianhydride precursor is monitored by high-resolution scanning tunneling microscopy. Our results show that the gold atoms in C-Au-C organometallic chains play a crucial role in promoting the selective ortho C-H bonds activation and forming Au-C4 coordination structure, which is further demonstrated by a comparative experiment of PTCDA precursor on Au(111). Furthermore, our experiment of 2Br-PTCDA precursor on Cu(111) substrate confirms that copper atoms in C-Cu-C organometallic chains can also assist the formation of Cu-C4 coordination structure. Our results reveal the vital effect of organometallic coordination on selective C-H bond activation of reactants, which holds promising implications for controllable on-surface synthesis.

A prognostic model based on necroptosis-related genes for prognosis and therapy in bladder cancer.

Bladder cancer, one of the most prevalent malignant cancers, has high rate of recurrence and metastasis. Owing to genomic instability and high-level heterogeneity of bladder cancer, chemotherapy and immunotherapy drugs sensitivity and lack of prognostic markers, the prognosis of bladder cancer is unclear. Necroptosis is a programmed modality of necrotic cell death in a caspase-independent form. Despite the fact that necroptosis plays a critical role in tumor growth, cancer metastasis, and cancer patient prognosis, necroptosis-related gene sets have rarely been studied in bladder cancer. As a result, the development of new necroptosis-related prognostic indicators for bladder cancer patients is critical. Herein, we assessed the necroptosis landscape of bladder cancer patients from The Cancer Genome Atlas database and classified them into two unique necroptosis-related patterns, using the consensus clustering. Then, using five prognosis-related genes, we constructed a prognostic model (risk score), which contained 5 genes (ANXA1, DOK7, FKBP10, MAP1B and SPOCD1). And a nomogram model was also developed to offer the clinic with a more useful prognostic indicator. We found that risk score was significantly associated with clinicopathological characteristics, TIME, and tumor mutation burden in patients with bladder cancer. Moreover, risk score was a valid guide for immunotherapy, chemotherapy, and targeted drugs. In our study, DOK7 was chosen to further verify our prognosis model, and functional assays indicated that knockdown the expression of DOK7 could prompt bladder cancer proliferation and migration. Our work demonstrated the potential role of prognostic model based on necroptosis genes in the prognosis, immune landscape and response efficacy of immunotherapy of bladder cancer.

Length-Dependent Magnetic Evolution of Anthenes on Au(111).

Nanographenes with zigzag edges, for example, anthenes, exhibit a unique nonbonding π-electron state, which can be described as a spin-polarized edge state that yields specific magnetic ground state. However, prior researches on the magnetism of anthenes with varying lengths on a surface is lacking. This study systematically fabricated anthenes with inherent zigzag carbon atoms of different lengths ranging from bisanthene to hexanthene. Their magnetic evolution on the Au(111) surface was analyzed through bond-resolved scanning probe techniques and density functional theory calculations. The analyses revealed a transition in magnetic properties associated with the length of the anthenes, arising from the imbalance between hybridization energy and the Coulomb repulsion between valence electrons. With the increasing length of the anthenes, the ground state transforms gradually from a closed-shell to an antiferromagnetic open-shell singlet, exhibiting a weak exchange coupling of 4 meV and a charge transfer-induced doublet. Therefore, this study formulated a chemically tunable platform to explore size-dependent π magnetism at the atomic scale, providing a framework for research in organic spintronics.

Nonplanar Rhombus and Kagome 2D Covalent Organic Frameworks from Distorted Aromatics for Electrical Conduction.

Two-dimensional (2D) covalent organic frameworks (COFs) are an emerging class of promising 2D materials with high crystallinity and tunable structures. However, the low electrical conductivity impedes their applications in electronics and optoelectronics. Integrating large π-conjugated building blocks into 2D lattices to enhance efficient π-stacking and chemical doping is an effective way to improve the conductivity of 2D COFs. Herein, two nonplanar 2D COFs with kagome (DHP-COF) and rhombus (c-HBC-COF) lattices have been designed and synthesized from distorted aromatics with different π-conjugated structures (flexible and rigid structure, respectively). DHP-COF shows a highly distorted 2D lattice that hampers stacking, consequently limiting its charge carrier transport properties. Conversely, c-HBC-COF, with distorted although concave-convex self-complementary nodes, shows a less distorted 2D lattice that does not interfere with interlayer π-stacking. Employing time- and frequency-resolved terahertz spectroscopy, we unveil a high charge-carrier mobility up to 44 cm2 V-1 s-1, among the highest reported for 2D COFs.

Identification of ENO1 as a prognostic biomarker and molecular target among ENOs in bladder cancer.

BACKGROUND: Enolase is an essential enzyme in the process of glycolysis and has been implicated in cancer progression. Though dysregulation of ENOs has been reported in multiple cancers, their prognostic value and specific role in bladder cancer (BLCA) remain unclear. METHODS: Multiple databases were employed to examine the expression of ENOs in BLCA. The expression of ENO1 was also validated in BLCA cell lines and tissue samples by western blotting and immunohistochemistry. Kaplan-Meier analysis, ROC curve, univariate and multivariate Cox regression were performed to evaluate the predictive capability of the ENO1. Gene ontology (GO) and Gene Set Enrichment Analyses (GSEA) analysis were employed to perform the biological processes enrichment. Function experiments were performed to explore the biological role of ENO1 in BLCA. The correlation of ENO1 with immune cell infiltration was explored by CIBERSORT. RESULTS: By analyzing three ENO isoforms in multiple databases, we identified that ENO1 was the only significantly upregulated gene in BLCA. High expression level of ENO1 was further confirmed in BLCA tissue samples. Aberrant ENO1 overexpression was associated with clinicopathological characteristics and unfavorable prognosis. Functional studies demonstrated that ENO1 depletion inhibited cancer cell aggressiveness. Furthermore, the expression level of ENO1 was correlated with the infiltration levels of immune cells and immune-related functions. CONCLUSIONS: Taken together, our results indicated that ENO1 might serve as a promising prognostic biomarker for prognosticating prognosis associated with the tumor immune microenvironment, suggesting that ENO1 could be a potential immune-related target against BLCA.

Compressive strain induced superior HER performance of nickel in alkaline solution.

The HER requires a highly efficient, cost-effective, and stable catalyst to adapt to the large-scale hydrogen industry. Nickel has been confirmed to be useful to drive the water splitting reaction, but the intrinsic performance remains unsatisfactory. In this work, nickel (EG-Ni) with compressive strain was prepared through a one-step electrochemical deposition strategy. It shows an outstanding enhancement for the HER, and it achieves a current density of 10 mA cm-2 at a low overpotential of 85.9 mV. A long-term durability test proves that the EG-Ni can tolerate a large current density of 100 mA cm-2, and the overpotential remains steady without dramatically increasing. Such a low overpotential and superior stability are attributed to the optimized adsorption energy on the catalyst surface, as evidenced by the downshifted position of the d-band center.

On-surface synthesis and characterization of nitrogen-doped covalent-organic frameworks on Ag(111) substrate.

Atomically precise fabrication of covalent-organic frameworks with well-defined heteroatom-dopant sites and further understanding of their electronic properties at the atomic level remain a challenge. Herein, we demonstrate the bottom-up synthesis of well-organized covalent-organic frameworks doped by nitrogen atoms on an Ag(111) substrate. Using high-resolution scanning tunneling microscopy and non-contact atomic force microscopy, the atomic structures of the intermediate metal-organic frameworks and the final covalent-organic frameworks are clearly identified. Scanning tunneling spectroscopy characterization reveals that the electronic bandgap of the as-formed N-doped covalent-organic framework is 2.45 eV, in qualitative agreement with the theoretical calculations. The calculated band structure together with the projected density of states analysis clearly unveils that the incorporation of nitrogen atoms into the covalent-organic framework backbone will remarkably tune the bandgap owing to the fact that the foreign nitrogen atom has one more electron than the carbon atom. Such covalent-organic frameworks may offer an atomic-scale understanding of the local electronic structure of heteroatom-doped covalent-organic frameworks and hold great promise for all relevant wide bandgap semiconductor technologies, for example, electronics, photonics, high-power and high-frequency devices, and solar energy conversion.

Establishment of an optimized orthotopic bladder cancer model in mice.

BACKGROUND: Bladder cancer (BC) is one of the most common malignancies of the genitourinary system. Animal models offer an important tool to explore tumour initiation, progression, and therapeutic mechanisms. Our aim is to construct an optimized orthotopic BC model which is predictable, reproducible, and convenient. METHODS: The optimized orthotopic BC model was constructed in male C57BL/6 mice utilizing microsyringes to inoculate them with a murine BC cell line (MB49). Anesthetised mice were inoculated with an MB49 cell suspension (10 µL) at approximately 5 × 106/mL. The whole process of modelling was observed and monitored every 3 days for 21 days utilizing HE staining and transabdominal ultrasonography (TUS). RESULTS: In this study, the model showed excellent success rates for tumour formation (96.67%) and metastatic rate (89.66%). Compared to the control group (sham operation), mice in the modelling group had serous cachexia, visible haematuresis and weight loss (all P < 0.05). The lungs, liver, ureter and kidneys were found to have tumour metastasis. Moreover, the average survival time (19.73 ± 1.69 d) of modelling mice was significantly shorter than that of the control mice (P < 0.05), which remained alive. CONCLUSION: Our study established a method using microsyringes to inject murine BC cells into the bladder wall, creating a stable transplantable BC model in mice.

On-Surface Synthesis of a Nitrogen-Doped Graphene Nanoribbon with Multiple Substitutional Sites.

Doped graphene nanoribbons (GNRs) with heteroatoms are a principal strategy to fine-tune the electronic structures of GNRs for future device applications. Here, we successfully synthesized the N=9 nitrogen-doped armchair GNR on the Au(111) surface. Due to the flexibility of precursor molecules, three different covalent bonds (C-C, C-N, N-N) are formed in the GNR backbone. Scanning tunneling spectroscopy analysis together with band structure calculations reveals that the band gap of the N-9-AGNRs (C-C) will be enlarged compared to pristine 9-AGNRs, and the C-N bond and N-N bond at the isolated site of N-9-AGNR (C-C) will introduce new defect states near the Fermi level. DFT calculations reveal that the electronic structure of N-9-AGNR (C-C) shows semiconductor character, while N-9-AGNR (C-N) and N-9-AGNR (N-N) display metallic character. Our results provide a promising route for creating more complex molecular heterostructures with tunable band gaps, which may be useful for future molecular electronics and memory device applications.

Loss of polarity protein Par3, via transcription factor Snail, promotes bladder cancer metastasis.

Bladder cancer (BLCA) remains the leading cause of cancer-related mortality among genitourinary malignancies worldwide. BLCA metastasis represents the primary reason for its poor prognosis. In this study, we report that decreased expression of partitioning defective 3 (Par3), a polarity protein (encoded by PARD3), is associated with tumor aggressive phenotypes and poor prognosis in BLCA patients. Consistently, ablation of Par3 promotes the metastasis and invasion of BLCA cells in vitro and in vivo. Further studies reveal that zinc finger protein Snail represses the expression of Par3 by binding to E2-box (CAGGTG) of PARD3 promoter-proximal. Inhibition of GSK-3ß promotes the expression and nuclear localization of Snail and then reduces the expression of Par3, resulting in the metastasis and invasion of BLCA cells. Moreover, we detected the interaction between Par3 (936-1356 aa) and ZO-1 (1372-1748 aa), which is involved in the maintenance of tight junction. Together, our results demonstrate that the GSK-3ß/Snail/Par3/ZO-1 axis regulates BLCA metastasis, and Snail is a major regulator for Par3 protein expression in BLCA.

Revealing the high-resolution structures and electronic properties of ZnTPP and its derivatives formed by thermally induced cyclodehydrogenation on Au(111).

Zinc(ii) tetraphenylporphyrin (ZnTPP) has very broad application prospects in the fields of supramolecular chemistry, solar cells and nanomaterials. In this paper, by using scanning tunneling microscopy (STM), we systematically investigated the ZnTPP molecule and its four derivatives formed by thermal annealing were characterized unambiguously by bond-resolved STM (BR-STM). The electronic properties of the ZnTPP molecule and its four cyclodehydrogenation products were investigated by scanning tunneling spectroscopy (STS) combined with DFT calculations. The spatial distribution of molecular frontier orbitals of four products was obtained by dI/dV mappings. This work gives rise to a full-scale investigation of ZnTPP on Au(111), which will be potentially useful in nanodevices and optoelectronics.