Exploring the evolving roles and clinical significance of circRNAs in head and neck squamous cell carcinoma.

Head and neck squamous cell carcinoma (HNSCC) represents the predominant malignancies in the head and neck region, and has limited therapeutic alternatives. Circular RNAs (circRNAs), a substantial category of non-coding RNA molecules, exert influential roles in human disease development and progression, employing various mechanisms such as microRNA sponging, interaction with RNA-binding proteins, and translational capabilities. Accumulating evidence highlights the differential expression of numerous circRNAs in HNSCC, and numerous dysregulated circRNAs underscore their crucial involvement in malignant advancement and resistance to treatment. This review aims to comprehensively outline the characteristics, biogenesis, and mechanisms of circRNAs, elucidating their functional significance in HNSCC. In addition, we delve into the clinical implications of circRNAs, considering their potential as biomarkers or targets for diagnosis, prognosis, and therapeutic applications in HNSCC. The discussion extends to exploring future challenges in the clinical translation of circRNAs, emphasizing the need for further research.

Lattice Strain Mediated Reversible Reconstruction in CoMoO4·0.69H2O for Intermittent Oxygen Evolution.

A heterogeneous interface usually plays a versatile role in modulating catalysis and the durability of hybrid electrocatalysts for oxygen evolution reaction (OER), and its intrinsic mechanism is still in dispute due to an uncertain correlation of initial, intermediate and active phases. In this article, the CoMoO4·0.69H2O/Co3O4 heterogeneous interface is configured to understand the evolution kinetics of these correlated phases. Due to the chemically and electrochemically "inert" character of Co3O4 support, lattice strain with 3.31% tuning magnitude in primary CoMoO4·0.69H2O can be inherited after spontaneous dissolution of molybdenum cations in electrolyte, dominating catalytic activity of the reconstructed CoOOH. In situ Raman spectroscopy demonstrates reversible conversion between active CoOOH and amorphous cobalt oxide during OER when positive and negative potentials are sequentially supplied onto hybrid catalysts with favorable strain. Therefore, superior durability with negligible decay after 10 cycles is experimentally identified for intermittent oxygen evolution. Theoretical calculations indicate that appropriate stress within the electrocatalyst could reduce the reaction energy barrier and enhance the OER performance by optimizing the adsorption of intermediates.

Conformal Shell Amorphization of Nanoporous Ag-Bi for Efficient Formate Generation.

Simultaneous attainments of high conductivity and superior catalysis are major challenges for amorphous electrocatalysts in carbon dioxide electroreduction at high overpotential. In this study, one protocol is first demonstrated to drive the shell amorphization of nanoporous Ag-Bi (a-NPSB) catalyst with the spatially interconnected ligament during the initial stage of CO2ER. This newborn a-NPSB bestows the outstanding catalysis, evidenced by a Faradaic efficiency of 88.4% for formate production at -1.15 V vs RHE, specific current density of 21.2 mA cm-2, and mass specific current density of 321 mA mg-1. The unique catalysis is considered as the collective contribution of the conductive ligament internally and amorphous Bi2O3 shell with about 3.2 nm thickness externally. Simultaneous obtaining of the conductivity of inner metals and catalytic activity of the amorphous shell will pave a new avenue for designing a robust electrode during electrochemical reaction.

The role of colloid formation in the photoinduced H2 production with a Ru(II)-Pd(II) supramolecular complex: a study by GC, XPS, and TEM.

The dinuclear RuII-PdII complex shows efficient H2 production in the presence of triethylamine as a sacrificial electron and proton donor under visible light irradiation. XPS and TEM analyses reveal that photoreduction of PdII to Pd0 causes dissociation of Pd from the complex to form colloids that are suggested to be the actual catalyst for H2 production.

Detection of intermediates in the TiO2-assisted photodegradation of Rhodamine B under visible light irradiation.

The photocatalytic degradation of dye Rhodamine B (RhB) in the presence of TiO2 nanostripe or P25 under visible light irradiation was investigated. The degradation intermediates were identified using Infrared spectra (IR spectra), 1H nuclear magnetic resonance (1HNMR) spectra, and gas chromatography-mass spectroscopy (GC-MS). The IR and the 1HNMR results showed that the large conjugated chromophore structure of RhB was efficiently destroyed under visible light irradiation in both the photocatalytic systems (TiO2 nanostripe or P25 and Rhodamine B systems). GC-MS results showed that the main identified intermediates were ethanediotic acid, 1,2-benzenedicarboxylic acid, 4-hydroxy benzoic acid and benzoic acid, which were almost the same in the TiO2 nanostripes and P25 systems. This work provides a good insight into the reaction pathway(s) for the TiO2-assisted photocatalytic degradation of dye pollutants under visible light irradiation.

Photodegradation of dye pollutants catalyzed by porous K3PW12O40 under visible irradiation.

Microporous solid K3PW12O40 is prepared by precipitation of phosphotungstic acid and potassium ion, followed by calcination. Using this material as photocatalyst, a series of dye pollutants, such as rhodamine B, malachite green, rhodamine 6G, fuchsin basic, and methyl violet, were efficiently degraded in the presence of H202 under visible light irradiation (lambda > 420 nm). The photocatalyst was characterized via SEM, BET surface area, FT-IR, and XRD. The photocatalyst has relative large surface area, and the Keggin structure of phosphotungstic ions is intact during the precipitation and calcination. The degradation kinetics, TOC changes, degradation products, ESR detection of active oxygen species, and the effect of radical scavengers are also investigated to clarify the degradation process and the reaction pathway. The dyes can be facilely bleached and mineralized (ca. 40% of TOC removal for RhB), and the main degradation products of RhB detected, besides CO2, are the small organic acids. They are released from the surface of the catalyst to the bulk solution during the degradation of the dye, which avoids the poisoning of photocatalyst by the intermediates. The formation of active oxygen species such as the O2-*/ HO2* and *OH are detected during the degradation of dye, and they are proposed to be responsible for the degradation of dyes. The K3PW12040 catalyst is very stable and very easily separated from the reaction system for reuse.

Degradation of dye pollutants by immobilized polyoxometalate with H2O2 under visible-light irradiation.

A Keggin polyoxometalate (POM, i.e., PW12O40(3-)) and its lacunary derivative are immobilized on an anionic exchange resin through electrostatic interaction at pH 4.6 in an aqueous dispersion. The resin-supported POM thus obtained catalyzes the efficient degradation of cationic dye pollutants in the presence of H2O2 under visible-light irradiation. To evaluate the photocatalytic system, degradation of a rhodamine B (RB) dye was investigated in detail using UV-visible spectroscopy, high performance liquid chromatography, and gas chromatography/mass spectrometry techniques to identify the intermediates and final products. Fluorescence lifetime measurements revealed the electron transfer from the visible-light-excited RB molecules to the POMs. Electron paramagnetic resonance measurements, investigation of the effects of *OH and *OOH scavengers on the photoreaction kinetics, and IR analysis indicated that de-ethylation of RB was due to *OOH radicals, but the decomposition of the conjugated xanthene structure was caused by the peroxo species formed by interaction of H2O2 with the lacunary POM loaded on the resin. A total organic carbon removal of ca. 22% was achieved, and the recycle experiment suggested excellent stability and reusability of the heterogeneous catalyst. On the basis of the experimental results, a photocatalytic mechanism is discussed.

Photosensitized degradation of dyes in polyoxometalate solutions versus TiO2 dispersions under visible-light irradiation: mechanistic implications.

This article examines the photoxidation of a dye (rhodamine-B, RhB) by visible-light irradiation in the presence of a polyoxometalate (12-tungstosilicic acid, H(4)SiW(12)O(40)), and compares it with the analogous process in the presence of TiO(2). The photoreaction processes were examined by UV-visible spectroscopy, fluorescence spectroscopy, high-performance liquid chromatography (HPLC), liquid chromatography/mass spectral techniques (LC-MS), and total organic carbon (TOC) assays in order to identify the intermediates produced. Formation of oxygen species, such as H(2)O(2) and O(2)*-, was also investigated to clarify the details of the reaction pathway. With the use of SiW(12)O(40)(4-) ions as the photocatalyst, the photoreaction leads mainly to N-dealkylation of the chromophore skeleton. In contrast, cleavage of the whole conjugated chromophore structure predominates in the presence of TiO(2). Strong O(2)*-/HO(2)*- ESR signals were detected in the TiO(2) dispersions, whereas only weak ESR signals for the O(2)*- radical ion were seen in the SiW(12)O(40)(4-) solutions during the irradiation period. Experimental results imply that reduction of O(2) occurs by different pathways in the two photocatalytic systems.

Photocatalysis by titanium dioxide and polyoxometalate/TiO2 cocatalysts. Intermediates and mechanistic study.

A representative polyoxometalate, alpha-12-tungstophosphatic acid (PW12(3-), POM), is loaded on the surface of TiO2 particles used as a cocatalyst to gain further insights into the underlying reaction mechanism and to estimate the feasibility of using the new POM/TiO2 cocatalyst in the photocatalytic degradation of 2,4-dichlorophenol (DCP) in aqueous media. Loading the PW12(3-) species on the surface of TiO2 enhances charge separation in the UV-illuminated TiO2, thereby accelerating the hydroxylation of the initial DCP substrate but not the mineralization of DCP, which is somewhat suppressed in the presence of the polyoxometalate. An increase in the load of POM increases the concentration of aromatic intermediates, and more toxic intermediates, such as 2,6-dichlorodibenzo-p-dioxin, 2,4,6-trichlorophenol, are detected in the PW12(3-)/TiO2 system. By contrast, cleavage of the whole conjugated structure of DCP predominates in TiO2 only dispersions. Strong ESR signals for the superoxide radical anionic species, O2*- (HO2* radicals in acidic media; pH < 5), are detected in TiO2 only dispersions; signals of O2*- are much weaker in the TiO2/ POM composite system under otherwise identical conditions. Experimental results infers that enhancement of charge separation in TiO2 photocatalysis does not always result in improvement of the efficiency of mineralization of organic substrates, and the reaction between organic radical cations and the formed superoxide radical anions may be responsible forthe mineralization of the chlorophenol.