Silicon oxide-protected nickel nanoparticles as biomass-derived catalysts for urea electro-oxidation

A universal approach to dual-metal-atom catalytic sites confined in carbon dots for various target reactions

Here, a molecular-design and carbon dot-confinement coupling strategy through the pyrolysis of bimetallic complex of diethylenetriamine pentaacetic acid under low-temperature is proposed as a universal approach to dual-metal-atom sites in carbon dots (DMASs-CDs). CDs as the "carbon islands" could block the migration of DMASs across "islands" to achieve dynamic stability. More than twenty DMASs-CDs with specific compositions of DMASs (pairwise combinations among Fe, Co, Ni, Mn, Zn, Cu, and Mo) have been synthesized successfully. Thereafter, high intrinsic activity is observed for the probe reaction of urea oxidation on NiMn-CDs. In situ and ex situ spectroscopic characterization and first-principle calculations unveil that the synergistic effect in NiMn-DMASs could stretch the urea molecule and weaken the N-H bond, endowing NiMn-CDs with a low energy barrier for urea dehydrogenation. Moreover, DMASs-CDs for various target electrochemical reactions, including but not limited to urea oxidation, are realized by optimizing the specific DMAS combination in CDs.

Prognostic and therapeutic implications of iron-related cell death pathways in acute myeloid leukemia

Acute myeloid leukemia (AML) is a blood cancer that is diverse in terms of its molecular abnormalities and clinical outcomes. Iron homeostasis and cell death pathways play crucial roles in cancer pathogenesis, including AML. The objective of this study was to examine the clinical significance of genes involved in iron-related cell death and apoptotic pathways in AML, with the intention of providing insights that could have prognostic implications and facilitate the development of targeted therapeutic interventions. Gene expression profiles, clinical information, and molecular alterations were integrated from multiple datasets, including TCGA-LAML and GSE71014. Our analysis identified specific molecular subtypes of acute myeloid leukemia (AML) displaying varying outcomes, patterns of immune cell infiltration, and profiles of drug sensitivity for targeted therapies based on the expression of genes involved in iron-related apoptotic and cell death pathways. We further developed a risk model based on four genes, which demonstrated promising prognostic value in both the training and validation cohorts, indicating the potential of this model for clinical decision-making and risk stratification in AML. Subsequently, Western blot analysis showed that the expression levels of C-Myc and CyclinD1 were significantly reduced after CD4 expression levels were knocked down. The findings underscore the potential of iron-related cell death pathways as prognostic biomarkers and therapeutic targets in AML, paving the way for further research aimed at understanding the molecular mechanisms underlying the correlation between iron balance, apoptosis regulation, and immune modulation in the bone marrow microenvironment.

Tin nanoparticle in-situ decorated on nitrogen-deficient carbon nitride with excellent sodium storage performance

Tin (Sn)-based electrodes, featuring high electrochemical activity and suitable voltage plateau, gain tremendous attention as promising anode materials for sodium-ion batteries. However, the application of Sn-based electrodes has been largely restricted by the serious pulverization upon repeated cycling due to their large volume expansion, especially at high current densities. Herein, a unique three-dimensional decorated structure was designed, containing ultrafine Sn nanoparticles and nitrogen-deficient carbon nitride (Sn/D-C₃N₄), to efficiently alleviate the expansion stress and prevent the aggregation of Sn nanoparticles. Furthermore, the density functional theory calculations have proved the high sodium adsorption ability and improved diffusion kinetics through the hybridization of D-C₃N₄ with Sn nanoparticles. Further combining the high electronic/ionic conductivity provided by the porous C₃N₄ matrix, high charge contribution from capacitive behavior, and high sodium storage activity of ultrafine Sn nanoparticles, the resultant Sn/D-C₃N₄ can achieve an ultrahigh reversible capacity of 518.3 mA g^-1 after 300 cycles at 1.0 A g^-1, and even maintaining a reversible capacity of 436.1 mAh g^-1 up to 500 cycles (5.0 A g^-1). What's more, the optimized Sn/D-C₃N₄∥Na₃V₂(PO₄)₃/C full cell can keep a high capacity retention of 87.1% at 1.0 A g^-1 even after 5000 cycles, manifesting excellent sodium storage performance.

Applications of nanomaterials for gastrointestinal tumors: A review

Nanotechnology is the emerging and advance field of research for the diagnosis and treatment of various diseases. With the development of nanotechnology, different nanoparticles are used in the treatment of cancer due to their unique optical properties, excellent biocompatibility, surface effects, and small size effects. Nanoparticles are the particles which have the particular size from 1 to 100 nm. These nanoparticles are zero dimension, one dimension, two dimension and three dimension etc. In present scenario a variety of research is focused on the tailored synthesis of nanoparticles for medicinal applications that can be used for cancer treatment based on the morphology, composition, interaction with target cell. The gastrointestinal (GI) tumors are found one of the deadest cancer types with highest reoccurrence rates. The diagnosis and treatment of gastrointestinal cancer is very challenging due to its deep location and complicated surgery. Nanotechnology provides fast diagnosis and immediate treatment for the gastrointestinal disease. A variety of nanomaterials are used for the diagnosis and treatment of GI disease. Nanoparticles target directly to the tumor cell as diagnostic and therapeutic tools facilitating the identification and removal of tumor cells. A number of nanoparticles are developed for the uses are quantum dots (QDs), carbon nanotubes (CNTs), metallic nanoparticles (MNPs), Dendrimers etc. This review article gives an overview of the most promising nanomaterials used for the diagnosis and treatment of GI diseases. This review attempts to incorporate numerous uses for the most current nanomaterials, which have great potential for treating gastrointestinal diseases.

In situ construction of Fe3O4@FeOOH for efficient electrocatalytic urea oxidation

Substituting water oxidation half of water splitting with anodic oxidation of urea can reduce the cost of H₂ production and provide an avenue for treating urea-rich wastewater. However, developing an efficient and stable electrocatalyst is necessary to overcome the indolent kinetics of the urea oxidation reaction (UOR). Accordingly, we have used the Schikorr reaction to deposit Fe₃O₄ particles on the nickel foam (Fe₃O₄/NF). Results from the various analysis indicated that under the operational conditions, Fe₃O₄ underwent surface reconstruction to produce a heterolayered structure wherein a catalytically active FeOOH layer encased a conducting Fe₃O₄. Fe₃O₄/NF outperformed RuO₂ as a UOR catalyst and delivered a current density of 10 50 and 100 mA cm^-2 at low applied potentials of 1.38 1.42 and 1.46 V, respectively, with a Tafel slope of 28 mV dec^-1. At the applied potential of 1.4 V, Fe₃O₄/NF demonstrated a turnover frequency (TOF) of 2.8 × 10^-3 s^-1, highlighting its superior intrinsic activity. In addition, a symmetrical urea electrolyzer constructed using Fe₃O₄/NF produced the current density of 10 mA cm^-2 at a cell voltage of 1.54 V.

Electrochemical sensor based on a chitosan-molybdenum vanadate nanocomposite for detection of hydroxychloroquine in biological samples

In this study, we firstly introduce an ultra-high sensitive V_3.6Mo_2.4O₁₆-chitosan (MV-CHT) nanocomposite for electrochemical hydroxychloroquine sulfate (HCQ) monitoring toward paracetamol (PCM) and pantoprazole (PPZ) in environmental and clinical diagnostics. The single-phase MV nanostructures are prepared via the sol-gel pechini route, followed by engineering maleic acid as a structure-directing agent. The stabilization of the MV electro-catalysts is adopted by varying critical factors such as calcination temperature, different chelating ligands, chelating molality and cross-linker concentration. The structural and morphological characterizations, namely, ordered active sites, structural integrity, porous network and dispersibility on the cationic polymer are confirmed by physicochemical analyses. Also, analytical nature of the MV-CHT modified carbon paste electrode (MV-CHT/CPE) is constructed via electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and differential pulse voltammetry (DPV) techniques. As a result, the nano-MV-CHT/CPE platforms with 10% of polymeric matrixes delivered the boosted analytical performance in terms of linear ranges (0.0019-194.0 µM), lower detection limit (LOD = 0.224 nM), together with excellent sensitivity and selectivity. The novel combination of MV nanoparticles and CHT provide the fluent channels for rapid charge transport and effective surface area. Such results illustrate the synergistic and interaction capability of MV-CHT-based sensing catalysts with bioactive molecules, which make them as superior drug monitoring devices.

Preparation of a nonenzymatic electrochemical sensor based on g-C3N4/MWO4 (M: Cu, Mn, ‎Co, Ni) composite for the determination of H2O2‎

‎ Hydrogen peroxide (H2O2) has a significant effect on physiological proceedings. In the ‎present research, a g-C3N4-based nanocomposite g-C3N4/MWO4(M: Cu, Mn, Co, Ni) was ‎prepared via the precipitation-calcination method. A...

Effect of metal and metal oxide engineered nano particles on nitrogen bio-conversion and its mechanism: A review

Metal and metal oxide engineered nano particles (MMO-ENPs) are widely applied in various industries due to their unique properties. Thus, many researches focused on the influence on nitrogen transformation processes by MMO-ENPs. This review focuses on the effect of MMO-ENPs on nitrogen fixation, nitrification, denitrification and Anammox. Firstly, based on most of the researches, it can be concluded MMO-ENPs have negative effect on nitrogen fixation, nitrification and denitrification while the MMO-ENPs have no promotion effect on Anammox. Then, the influence factors are discussed in detail, including MMO-ENPs dosage, MMO-ENPs kind and exposure time. Both the microbial morphology and population structure were altered by MMO-ENPs. Also, the mechanisms of MMO-ENPs affecting the nitrogen transformation are reviewed. The inhibition of key enzymes and functional genes, the promotion of reactive oxygen species (ROS) production, MMO-ENPs themselves and the suppression of electron transfer all contribute to the negative effect. Finally, the key points for future investigation are proposed that more attention should be attached to the effect on Anammox and the further mechanism in the future studies.

Self-driven Ru-modified NiFe MOF nanosheet as multifunctional electrocatalyst for boosting water and urea electrolysis

Urea electro-oxidation reaction (UOR) has been a promising strategy to replace oxygen evolution reaction (OER) by urea-mediated water splitting for hydrogen production. Naturally, rational design of high-efficiency and multifunctional electrocatalyst towards UOR and hydrogen evolution reaction (HER) is of vital significance, but still a grand challenge. Herein, an innovative 3D Ru-modified NiFe metal-organic framework (MOF) nanoflake array on Ni foam (Ru-NiFe-x/NF) was elaborately designed via spontaneous galvanic replacement reaction (GRR). Notably, the adsorption capability of intermediate species (H*) of catalyst is significantly optimized by Ru modification. Meanwhile, rich high-valence Ni active species can be acquired by self-driven electronic reconstruction in the interface, then dramatically accelerating the electrolysis of water and urea. Remarkably, the optimized Ru-NiFe-③/NF (1.6 at% of Ru) only requires the overpotential of 90 and 310 mV to attain 100 mA cm^-2 toward HER and OER in alkaline electrolyte, respectively. Impressively, an ultralow voltage of 1.47 V is required for Ru-NiFe-③/NF to deliver a current density of 100 mA cm^-2 in urea-assisted electrolysis cell with superior stability, which is 190 mV lower than that of Pt/C-NF||RuO₂/NF couple. This work is desired to explore a facile way to exploit environmentally-friendly energy by coupling hydrogen evolution with urea-rich sewage disposal.

Surfactant-mediated morphology evolution and self-assembly of cerium oxide nanocrystals for catalytic and supercapacitor applications

Surfactant plays a remarkable role in determining the growth process (facet exposition) of colloidal nanocrystals (NCs) and the formation of self-assembled NC superstructures, the underlying mechanism of which, however, still requires elucidation. In this work, the mechanism of surfactant-mediated morphology evolution and self-assembly of CeO2 nanocrystals is elucidated by exploring the effect that surfactant modification has on the shape, size, exposed facets, and arrangement of the CeO2 NCs. It is directly proved that surfactant molecules determine the morphologies of the CeO2 NCs by preferentially bonding onto Ce-terminated {100} facets, changing from large truncated octahedra (mostly {111} and {100} exposed), to cubes (mostly {100} exposed) and small cuboctahedra (mostly {100} and {111} exposed) by increasing the amount of surfactant. The exposure degree of the {100} facets largely affects the concentration of Ce3+ in the CeO2 NCs, thus the cubic CeO2 NCs exhibit superior oxygen storage capacity and excellent supercapacitor performance due to a high fraction of exposed active {100} facets with great superstructure stability.

Metal-organic frameworks-derived hollow dodecahedral carbon combined with FeNx moieties and ruthenium nanoparticles as cathode electrocatalyst for lithium oxygen batteries

Owing to their high energy density, lithium-oxygen batteries (LOBs) have been drawn great attention as one of the promising electrochemical energy sources. However, the sluggish kinetics of oxygen reduction/evolution reaction (ORR/OER) hamper the widespread application of LOBs. Herein, an elaborate designed catalysts which are constructed by FeN_x moieties dispersed on the network-like hollow dodecahedral carbon and then decorated with Ru nanoparticles (FeN_x-HDC@Ru). Since the homogeneously dispersed FeN_x moieties could promote ORR performance, and the Ru nanoparticles could facilitate OER capability, the FeN_x-HDC@Ru nanocomposites used as cathode catalysts can significantly improve LOBs performance. A lower discharge and charge overpotentials of 0.15 V and 0.78 V can be detected in the first cycle, respectively, and an excellent cycle performance of 90 cycles at 200 mA g^-1 and 89 cycles at 500 mA g^-1 can be demonstrated. Herein, the charge transfer kinetics has been enhanced with the internal network-like hollow structure and a low impedance Li₂O₂/catalysts contact interface could be earned by the constructed Ru nanoparticles, these factors would lead to an efficient acceleration to the formation and decomposition of Li₂O₂ during discharge and charge process.