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Insights into different photocatalytic oxidation activities of anatase, brookite, and rutile single crystal facets
摘要： For the understanding of the activity of TiO2 photocatalysts knowledge of the activities of different crystal facets is necessary. This information can be achieved by the investigation of well-defined single crystalline TiO2 surfaces. In this study, the photocatalytic activity of different anatase, brookite, and rutile single crystal wafers with only one exposed surface has been investigated via the oxidation of methanol and the hydroxylation of terephthalic acid, respectively. XRD and SEM measurements have shown that all surfaces are clearly defined and possess a smooth surface, which allows a reliable comparison of the photocatalytic activities. The investigated anatase surfaces show a higher activity than the rutile surfaces, while the brookite surface is interestingly the least active one. To the best of our knowledge, there are no other reports based on the investigation and comparison of well-defined TiO2 anatase (100), anatase (001), and brookite (100) single crystalline surfaces concerning their photocatalytic activity. Furthermore, the influence of the coordination of the titanium and the oxygen ions on the photocatalytic activity is discussed.
关键词： rutile,terephthalic acid hydroxylation,anatase,TiO2 modifications,photocatalytic methanol oxidation,TiO2 surfaces,brookite,single crystalline surfaces
更新于2025-09-09 09:28:46
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A comprehensive review on thin film-based nano-biosensor for uric acid determination: arthritis diagnosis
摘要： This article aims to provide a survey on the development of thin film-based nano-biosensor over the decade, which includes sensing principles, electrode types and various thin film matrices. The theoretical and experimental results suggest that the thin film-based sensor are suitable for highly sensitive detection of low concentration bio molecules and can be used for early diagnosis and screening of arthritis, kidney diseases and other cardiovascular diseases. This review concludes that enzyme immobilisation and surface functionalisation methods were used to increase sensitivity of the biosensor and new combination of polymer nano-composites with metal oxide thin films results in increased efficiency due to its high biocompatibility.
关键词： nanomaterials,enzymes,thin films,uric acid,immobilisation,biocompatibility
更新于2025-09-09 09:28:46
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Gold nanoparticle/nickel oxide/poly(pyrrole-N-propionic acid) hybrid multilayer film: Electrochemical study and its application in biosensing
摘要： The present study describes the fabrication of Indium Tin Oxide /gold nanoparticles/nickel oxide/poly(Pyrrole-N-propionic acid) (ITO/GNPs/NiO/poly(PPA)) multilayered film, and its modification with Tyrosinase (Ty). The ITO/GNPs/NiO/poly(PPA) electrode was fabricated by sequential electrochemical assembly onto ITO substrate which electrochemical deposition provides a facile, inexpensive technique for synthesis of multilayered film within the adherent morphology with controllable film thickness. Cyclic voltammetry (CV), Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR), scanning electron microcopy (SEM), and atomic force microcopy (AFM) were used to characterize the film assembly processes. The properties of a semiconductor/electrolyte interface were investigated based on the Mott–Schottky (M-S) approach for the modified electrodes, with the flat band potential (EFB) according to the potential intercept and the carrier density (ND) according to the linear slopes. The ND and EFB of ITO/GNPs/NiO/poly(PPA) were obtained as 2.48·1021 cm–3 and 0.26 V, respectively. Tyrosinase was immobilized using carbodiimide coupling reaction. The bioelectrode was characterized by FTIR-ATR, SEM, AFM, electrochemical impedance spectroscopy (EIS). A Randles equivalent circuit was introduced for modeling the performance of impedimetric biosensing for the detection of the dopamine (DP) and the interface of bioelectrode/electrolyte. The EIS of the ITO/GNPs/NiO/poly(PPA)-Ty exhibited significant changes in the charge transfer resistance (RCT) value toward the detection of dopamine over a linear range of 80 μM to 0.2 mM with a limit of detection (LOD) of 5.46 μM.
关键词： tyrosinase,poly(pyrrole-N-propionic acid),polymer composites,Mott–Schottky,dopamine
更新于2025-09-09 09:28:46
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Photomedicine - Advances in Clinical Practice || Photodynamic Therapy
摘要： Photodynamic therapy (PDT) employs light activation of tissue‐localized photosensitizer in an oxygen‐dependent process which initiates oxidative stress, inflammation, and cell death. Photodynamic therapy (PDT) involves the activation of a previously administered photosensitizing agent by visible light to induce tumor necrosis. Photosensitizers are topically applied in the treatment of skin tumors to avoid systemic side effects. The main dermatology indications for topical PDT are superficial nonmelanoma skin cancer and dysplasia, notably superficial basal carcinoma (BCC), Bowen's disease (BD), and actinic keratosis (AK). In this chapter, we evaluated the feasibility and efficacy of aminolevulinic acid (ALA) as a photosensitizer (ALA‐PDT) in combination with CO2 laser in the treat‐ment of dermatological disease from basics to clinic research.
关键词： photosensitizer,photodynamic therapy,Bowen's disease,actinic keratosis,aminolevulinic acid
更新于2025-09-09 09:28:46
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Use of Phenolic Compounds as Stabilizing Agents for Silicon-Based Molecules
摘要： In order to circumvent the problem of silanols polymerization in food supplement or cosmetics, the stabilizing power of phenolic molecules such as vanillin and frambinone was evaluated using two different siliceous molecules: orthosilicic acid and monomethylsilanetriol. NMR analyses confirmed the absence of polymeric species in formulations, conferring it a good bioavailability. The Silicon-phenol complexes demonstrated interesting biological properties on skin, collagen and cellular ageing proving that this complex reveals all the power of Silicon.
关键词： Monomethylsilanetriol,Silicon,Bioavailability,Orthosilicic acid
更新于2025-09-09 09:28:46
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Fundamental investigation on interaction between hexafluoroisopropylalcohol-containing styrene and photochemical acid generator for rationale design of photoresist system
摘要： This article presents the effect of some ionic photochemical acid generators (PAGs) to inhibit the dissolution of hexafluoroisopropylalcohol (HFA)-containing polystyrene to an aqueous alkaline developer, which is a highly important effect in photoresist application to enhance resolution of patterning. The dissolution inhibiting factors and mechanisms were investigated by evaluating the solubility and the 1H-NMR analysis of OH proton in HFA moiety. The dissolution inhibition effect was enhanced when the structures of PAGs fulfill some requirements: (a) their anions should have higher basicity and smaller van der Waals volume; (b) their cations should be stabilized by conjugation with electron-rich aromatics. In the dissolution inhibition, the HFA moiety interacts with the anionic part of PAGs liberated from the electrostatic interaction with the counter cation. These interactions were predicted and quantified by DFT calculations using Gaussian 09, leading to the rational designs of PAGs with higher dissolution inhibiting effect in photoresist systems.
关键词： fluoropolymers,photochemical acid generator,calculations,dissolution inhibition effect,photoresists
更新于2025-09-09 09:28:46
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Temperature and frequency effect on the electrical properties of bulk nickel phthalocyanine octacarboxylic acid (Ni-Pc(COOH)8)
摘要： The AC conductivity of nickel phthalocyanine octacarboxylic acid was investigated from 100 Hz to 1 MHz and temperature from 290 to 423 K. The AC conductivity was found to vary with frequency (σ(f)) and form two dispersion regions; the associated exponent factor “s” values were found to vary from 1.17 to 1.34 and from 0.42 to 0.67 (< 1). The value and temperature dependent of s are found in agreement with conduction mechanism models of large-polaron tunneling and the correlated barrier hopping, at the first and the second regions, respectively. The real and the imaginary parts of the dielectric constant were observed to decrease as the frequency increases indicating the pronounce contribution of low-frequency polarization mechanisms. Furthermore, the activation free energy ?F, enthalpy ?H, and entropy ?S of the sample were calculated as well.
关键词： enthalpy,polarization mechanisms,AC conductivity,activation free energy,dielectric constant,nickel phthalocyanine octacarboxylic acid,entropy
更新于2025-09-09 09:28:46
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Locked Nucleic Acid Nanomicelle with Cell-Penetrating Peptides for Glutathione-Triggered Drug Release and Cell Fluorescence Imaging
摘要： Herein, we constructed a multi-functional spherical nanomicelle drug delivery system to improve the efficiency of cell uptake. The paclitaxel (PTX)-locked nucleic acid (LNA) monomer and the carboxyfluorescein (FAM)-labeled DNA was mixed together to assemble and form a spherical nanomicelle which was functionalized with transactivator of transcription (TAT), a cell-penetrating peptides (CPPs). A bioreductively activated disulfide was used to link the hydrophobic PTX to the LNA, allowing the PTX to be released freely in the presence of glutathione (GSH) upon cell uptake. Based on magnetic separation, synthetic process of PTX-LNA monomers avoid time-consuming and labor-intensive shortcoming. Cellular uptake of PTX-LNA-TAT nanomicelle and the drug release occur rapidly as proved by fluorescence microscopy and flow cytometry. The resulting nanomicelle was greater stability, monodisperse size, and the high therapeutic potential. Furthermore, the system can readily achieve detection of GSH in the cancer cells. The detection limit for commercial GSH determined was 1.0×10-9 M by using PTX/Fluorescein isothiocyanate (FITC)-LNA/ black hole quencher 1 (BHQ-1) as a probe.
关键词： glutathione,delivery system,locked nucleic acid,magnetic separation,transactivator of transcription peptide
更新于2025-09-09 09:28:46
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Comparative Study of Single Molecular Junctions with <i>Para</i> -Phthalic Acid and <i>Meta</i> -Phthalic Acid Binding to Different Metal Electrodes
摘要： In this paper, single molecular junctions of para-phthalic acid and meta-phthalic acid with Au electrodes were studied by STM break junction approach. Conductance values of 10?3(cid:2)55 G0 and 10?3(cid:2)70 G0 were found for para-phthalic acid and meta-phthalic acid, respectively. The conductance order between para-phthalic acid and meta-phthalic acid with Au is different from that with Cu, which can be contributed to the different coupling between molecules and electrodes; different through-space interaction is proposed for such phenomenon between Cu and Au electrodes. Furthermore, the breaking off distances can re?ect the length of molecules. The current work presents the important role of electrode in single molecular junctions with different position anchoring groups.
关键词： STM-BJ,Meta-Phthalic Acid,Carboxylic Acid,Para-Phthalic Acid,Single-Molecule Junctions
更新于2025-09-04 15:30:14
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Synthesis, Crystal Structure and Photophysical Properties of Two Reduced Schiff Bases Derived from 5-Aminoisophthalic Acid
摘要： Two reduced Schiff bases, namely 5-[(2-hydroxybenzyl)amino]isophthalic acid (1) and 5-[(pyridin-4-ylmethyl)amino] isophthalic acid (2), were synthesized in two-step method using 5-aminoisophthalic acid as the starting material, and were characterized by single-crystal X-ray diffraction, elemental analysis, infrared, 1H NMR, mass, absorption and fluorescence spectra. Both 1 and 2 crystallize in monoclinic system with space groups P21/c for 1 and P21/n for 2. Photophysical properties of both 1 and 2 are significantly different from those of raw material 5-aminoisophthalic acid due to stronger p → π conjugation when one amino hydrogen atom in 5-aminoisophthalic acid is substituted with electron-donor group. 1 displays a very strong narrow-band blue fluorescence with the maximum peak at 439 nm, a high quantum efficiency up to 64%, and a narrow full width at half maximum of 35 nm, while 2 has a broader and weaker fluorescence with the peak at 418 nm and FHWM of about 50 nm.
关键词： 5-[(2-Hydroxybenzyl)amino]isophthalic acid,5-Aminoisophthalic acid,Photophysical property,5-[(Pyridin-4-ylmethyl)amino]isophthalic acid,Crystal structure,Reduced Schiff base
更新于2025-09-04 15:30:14