Ultraviolet-visible Spectroscopy Research Articles

Targeting Mycobacterium tuberculosis Parallel G-Quadruplex Motifs with Aminoglycosides Neomycin and Streptomycin: Spectroscopic and Calorimetric Aspects.

Mycobacterium tuberculosis (Mtb) contains potential G-quadruplex (PGQ) motifs in the genes espK and cyp51, which are crucial for the bacteria's virulence within host cells. Aminoglycoside molecules are commonly used as antibiotics for ribosomal targets. This study provides insight into the interactions between these aminoglycosides and Mtb-PGQ sequences (espK and cyp51), shedding light on the structural and thermodynamic dynamics of their binding. This study demonstrates the stability, affinity, and conformation of Mtb-PGQ in the presence of neomycin and streptomycin. Ultraviolet-visible spectroscopy (UV-vis), circular dichroism spectroscopy (CD), CD thermal melting, isothermal titration calorimetry (ITC), and fluorescence intercalator displacement (FID) assays were used to comprehensively examine these interactions. Our results reveal that neomycin with Mtb-PGQexhibits hypochromism accompanied by a 4-5 nm red shift in the UV-visible absorption titration, whereas streptomycin exhibits a hypochromic shift without changes in the maximum wavelength. Notably, neomycin shows a nonlinear binding isotherm, suggesting the involvement of more than one binding process in the formation of neomycin.Mtb-PGQ complexes. Scatchard plot analysis indicates higher binding affinity values for neomycin compared with weaker affinity of streptomycin. CD studies reveal that neomycin decreases the ellipticity of Mtb-PGQ with a red shift while retaining the parallel topology, ultimately enhancing the thermal stability of both espK and cyp51. In contrast, streptomycin destabilizes the cells. ITC analysis reveals that neomycin exhibits the strongest binding affinity for cyp51, with the relative order being NEO-cyp51 > NEO-espk > STR-cyp51 > STR-espk. Moreover, thermodynamic analysis reveals that neomycin possesses a unique dual mode of binding through grooves as well as stacking. FID studies further confirm a lower DC50 value for neomycin than for streptomycin, suggesting that neomycin is a strong displacer of thiazole orange. Thus, the results show that neomycin with amino groups selectively recognizes the grooves of cyp51 over espK.

Isotherms, Kinetics and Thermodynamics of Removal of Pb (II), Cd (II) and Cr (III) Ions in Wastewater onto Green Silver Nanoparticle Adsorbent

Moringa oleifera leaf extract mediated silver nanoparticles (MOR-AgNPs) were synthesized from a water-soluble leaf using a green technique. The plant's secondary metabolites served as capping and reducing agent. The spectroscopic characterization of the material was carried out by means of Scanning Electron Microscope (SEM), Ultraviolet-Visible Spectroscopy (Uv-vis), X-ray Diffraction Spectroscopy (XRD), Fourier Transform Infrared (FTIR) spectroscopy, Transition Electron Microscope (TEM), Energy Dispersion Spectroscopy (EDS), and Dynamic Light Scattering (DLS). The UV–Vis spectrum showed absorption peak between 400 – 500 nm, while TEM revealed spherical images of sizes in the nano region. The MOR-AgNPs adsorbent uptake of the metal ions was optimized by varying concentration, shaking time, adsorbent mass, pH, and temperature conditions. The isotherm models studies revealed that the type-1 Langmuir fitted well to the adsorption showing monolayer/homogeneous adsorption. The second order kinetics fitted well to the adsorption study, while positive values of ΔH° and ΔS° indicated endothermic and increased randomness at the MOR-AgNPs-aqueous interface. The ΔG° showed that the sorption of the metal ions onto the adsorbent was spontaneous, making the adsorption process feasible. The Ea values for the metal ion adsorption onto the adsorbent used in this study suggest a physical adsorption process. The adsorption capacity of 294.15 mg/g (40 °C, and pH of 6) of Cd(II), 123.63 mg/g (40 °C, and pH 10) of Pb(II), and 122.93 mg/g (40 °C, and pH 6) of Cr (III) ions on MOR-AgNPs adsorbent were obtained.

Studies on Polyvinyl Pyrrolidone (PVP) and Tapioca-Based Polymer Nanocomposites for Solid Polymer Electrolyte Applications in Batteries

Blending polymers has wide applications in batteries, since it possess different physical and chemical properties. In this study blending of PVP/tapioca and PVP/tapioca/polyamide have been prepared and characterized. The compatibility or miscibility of the polymers at the molecular level determines the new properties of the polymer blends. The synthesised polymer blends were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet-Visible Spectroscopy (UV-Vis) and Atomic Force Microscopy (AFM). Acoustical and excess parameters were studied for blends of PVP/tapioca and PVP/tapioca/polyamide in organic solids. By measuring ultrasonic velocity and adiabatic compressibility, the excess parameters were used to determine the nature of polymer interactions in the solvent.The topographical images are shown small particles approximately 50 nm in size, medium particles 100 nm in size, and large particles 175 nm in size were all observed. All particles exhibited a lobed-type fine structure; for the 175 nm sized particles, the lobes were 50 nm – 175 nm in size and appeared evenly distributed around the center of the particles.

Assessment of the In Vitro Biological Activities of Schiff Base-Synthesized Copper Oxide Nanoparticles as an Anti-Diabetic, Anti-Alzheimer, and Anti-Cancer Agent

Background/Objectives: Numerous diseases such as diabetes, Alzheimer’s disease, and cancer have spread in the whole world, especially in the Arab world. Also, various applications of Schiff-base functionalized nanoparticles and copper oxide nanoparticles (CuO-NPs) such as therapeutic applications have been discovered. Thus, the current research highlights (i) the synthesis of copper oxide nanoparticles (CuO-NPs) produced with a Schiff base (SB) serving as a capping agent during their synthesis and (ii) assessment of the in vitro biological activities of Schiff base-synthesized copper oxide nanoparticles (SB-CuO-NPs) and a Schiff base (SB). Methods: SB-CuO-NPs were characterized using ultraviolet-visible (UV-Vis) spectroscopy, zeta potential, DLS analysis, and transmission electron microscope (TEM). It also focuses on assessing the in vitro biological applications and activities, including antioxidant, scavenging, anti-diabetic, anti-Alzheimer, anti-arthritic, anti-inflammatory, cytotoxic activities, and enzymes inhibitory potential, of Schiff base-synthesized copper oxide nanoparticles (SB-CuO-NPs) and a Schiff base (SB) using methods described in the literature. Results: The results of the biological activities of the SB-CuO-NPs were compared with those of the SB. The SB-CuO-NPs demonstrated superior in vitro biological activities when compared to the SB from which they were produced. Conclusions: The results of this investigation concluded that the CuO-NPs, synthesized with the SB serving as an alternative capping agent, exhibited enhanced biological efficacy relative to the original SB. In the future, the biological efficiency of SB-CuO-NPs against diabetes, Alzheimer’s, and cancer diseases will be assessed in experimental animals (in vivo).

To Explore the Antimicrobial Properties of Co- doped CdO Nanoparticles prepared by sol-gel Citrate Techniques

This study focuses on the synthesis of Cadmium oxide (CdO) nanoparticles with doped transition metals like Cobalt (Co) of varying concentrations using sol gel citrate synthesis. Chemical and elemental characterization was carried out with X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet-Visible (UV-Vis) spectroscopy, Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS). The efficacy of antimicrobial properties of the synthesized nanoparticles against a wide range of Gram-positive and Gram-negative bacterial strains and fungal strains was explored. The results demonstrates that the doping of transition metals enhances the antibacterial and antifungal properties of the CdO nanoparticles and thus it can be used as antimicrobial agent in various industrial and medical fields due to its potential strength.

Physicochemical Characterization of Hyaluronic Acid-Methylcellulose Semi-Gels for Mitochondria Transplantation.

Traumatic spinal cord injury (SCI) presents a significant medical challenge due to its intricate nature and treatment complexities. SCI can cause physical impairments by affecting neural and motor functions as well as initiating a series of pathophysiological events exacerbating the initial trauma. Leakage from ruptured neurons and vessels disrupt ionic balance and induces excitotoxicity, leading to progressive cellular degeneration. Introducing mitochondria to the SCI lesion has shown potential in attenuating secondary injury. Mitochondria transplantation improves cellular bioenergetics and reduces concentration of reactive oxygen species achieving homeostasis and neuroprotection. Nonetheless, keeping mitochondria viable outside cell environment for a time longer than a few minutes proves to be challenging. Additionally, localized delivery to the injury site has also been limited by other factors including flow rate of cerebrospinal fluid that washes away mobilized organelle from the compromised tissue site. Previously we showed that using hyaluronic acid-methylcellulose semi-gels (HAMC) as a biocompatible, erodible thermogelling delivery vehicle helped to overcome some of these challenges. HAMC allows for controlled release at and around the injury site, utilizing the reverse thermogelling property of MC. Sustained release of mitochondria at slower rate can increase their uptake in spinal tissue. To better optimize the semi-gel delivery of mitochondria requires a more complete understanding of the physicochemical properties of the HAMC semi-gels. We have used ultraviolet-visible spectroscopy to measure optical density of HAMC semi-gels for different HA to MC ratios and examine the temperature dependent gelation properties above their low critical solution temperature (LCST). The viscosity and degree of crystallinity of the resulting HAMC semi-gels were also assessed. Semi-gel erosion and mitochondrial release over time were studied using a fluorescence microplate reader. Lastly, seahorse assay was used to study released mitochondria respiration and viability after incubation in HAMC semi-gel.

Microscopic Characterization Based Synthesis of Silver Nanoparticles Using Merremia quinquefolia (L.) Hallier f. Leaf Extract: Their Biological Approaches and Degradation of Methylene Blue Dye.

The green methods for the synthesis of silver nanoparticles (AgNPs) has developed popularity recently due to the low preparation costs, environmental friendliness, and non-toxicity of the precursors. In this study, AgNPs were synthesized using leaf extract from Merremia quinquefolia. Spectroscopic techniques were used for analyzing the functional groups, morphology, crystalline phase, and elemental composition of nanomaterials. The ultraviolet (UV) visible spectrometry absorption spectra of the AgNPs had a surface plasmon resonance band at 459 nm and Fourier transformed infrared spectrum (FTIR) analysis showed the presence of elements groups. X-ray diffraction (XRD) analysis indicates the crystalline structure and the energy-dispersive x-ray spectroscopy (EDAX) analysis shows strong signals for the silver element. Morphological analysis using transmission electron microscope (TEM) and scanning electron microscopy (SEM) analyses revealed that the AgNPs exhibited spherical shapes with an average size of 14 nm. Furthermore, it was indicated by the Raman spectra vibrational peak at 240 and 470 cm-1. The disk diffusion method showed that AgNPs were highly effective in inhibition of Gram-positive bacteria Staphylococcus aureus with a high inhibitory zone (14 ± 0.23 mm). Antioxidant activity, the IC50 values for assays DPPH (145.7 μg/mL) and ABTS (112.09 μg/mL), and albumin denaturation in human red blood cells showed higher anti-inflammatory activity. AgNPs had an IC50 value of 4.62 μg/mL against breast cancer (MCF-7) cells. Methylene blue (MB) degrading studies were used to assess the photocatalytic activity of AgNPs. They are at 240 min observed sunlight, the MB degradation efficiency was 94.89%. Overall, although M. quinquefolia synthesizes AgNPs for environmentally friendly applications, the study is indicated to fully understand the potential involved in treating breast cancer cells.

Mangifera indica–driven CuO nanoparticles: properties for sensing and optoelectronics

This study reports biological synthesis of Mangifera indica leaf extract–mediated copper oxide nanoparticles (CuO NPs). CuO NPs are characterized for crystal structure and crystallite size determination, absorption peak, particle size and morphological analysis, elemental composition, and functional groups’ identification using X-ray diffraction (XRD), ultraviolet–visible spectroscopy, high-resolution transmission electron microscope (HRTEM), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectrometer (EDS), and Fourier transform infrared (FTIR). NPs show an absorption peak ∼338 nm and Tauc’s plot gives band gap energy ∼2.2 eV. XRD pattern depicts monoclinic phase ∼18 nm average crystallite size NPs. FESEM and HRTEM micrographs confirm the needle-shaped NPs having 5:40 nm aspect ratio. The EDS spectrum, depicting the Cu and O peaks, shows that the particles are free from any type of impurity. FTIR analysis elucidates the role of bioactive chemicals in the extract in the successful formation of NPs. The photoluminescence study reveals the existence of violet, green, orange, yellow, and red emission bands. Also, NPs exhibit an electrical conductivity of 1.37 × 10–7 S/m and 5. 31 × 10–7 S/m at 100°C and 200°C. Thus, environmentally friendly, non-toxic, green-synthesized CuO NPs hold significant potential for applications in resistive sensors, solar cells, and optoelectronics devices.

Photochemistry of Microsolvated Nitrous Acid: Observation of the Water-Separated Complex of Nitric Oxide and Hydroxyl Radical.

The photochemistry of nitrous acid (HONO) plays a crucial role in atmospheric chemistry as it serves as a key source of hydroxyl radicals (OH) in the atmosphere; however, our comprehension of the underlying mechanism for the photochemistry of HONO especially in the presence of water is far from being complete as the transient intermediates in the photoreactions have not been observed. Herein, we report the photochemistry of microsolvated HONO by water in a cryogenic N2 matrix. Specifically, the 1:1 hydrogen-bonded water complex of HONO was facially prepared in the matrix through stepwise photolytic O2 oxidation of the water complex of imidogen (NH-H2O) via the intermediacy of the elusive water complex of peroxyl isomer HNOO. Upon photolysis at 193 nm, the matrix-isolated HONO-H2O complex decomposes by yielding the ternary water complex of OH and NO due to the matrix cage effect. The identification of this rare water-separated radical pair (OH-H2O-NO) with matrix-isolation infrared and ultraviolet-visible spectroscopy is aided by D, 15N, and 18O isotope labeling and quantum chemical calculations at the (U)CCSD/AVTZ level of theory, and its most stable structure exhibits separate hydrogen bonding interactions of the OH and NO radicals with H2O via OH···OH2 and ON···HOH contacts, respectively. This ternary complex is extremely unstable, as it undergoes spontaneous radical recombination to reform the HONO-H2O complex in the temperature range of 4-12 K through quantum-mechanical tunneling with 16/18O, H/D, 14/15N kinetic isotopic effects of 1.43, 2.33, and 0.91, respectively. At increased temperatures from 15 to 21 K, the recombination proceeds predominantly by overcoming the activation barrier with an estimated height of 0.12(1) kcal/mol.

The study of pure and Ni Doped CdO nanoparticles to explore their Antimicrobial Activity

This study focuses on the synthesis of Cadmium oxide (CdO) nanoparticles with doped transition metals like Nickel (Ni) of varying concentrations using sol gel citrate synthesis. Chemical and elemental characterization was carried out with X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet-Visible (UV-Vis) spectroscopy, Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS). The efficacy of antimicrobial properties of the synthesized nanoparticles against a wide range of Gram-positive and Gram-negative bacterial strains and fungal strains was explored. The results demonstrates that the doping of transition metals enhances the antibacterial and antifungal properties of the CdO nanoparticles and thus it can be used as antimicrobial agent in various industrial and medical fields due to its potential strength.

Structural Changes in Atomically Precise Ag29 Nanoclusters upon Sequential Attachment and Detachment of Secondary Ligands.

Elucidating the structural dynamics of ligand-stabilized noble metal nanoclusters (NCs) is critical for understanding their properties and for developing applications. Ligand rearrangement at NC surfaces is an important contributor to structural change. In this study, we investigate the dynamic behavior of ligand-protected [Ag29(L)12]3- NC's (L = 1,3-benzenedithiol) interacting with secondary ligand 2,2'-[1,4-phenylenebis (methylidynenitrilo)] bis[benzenethiol] (referred to as L'). We specifically focus on the structural characteristics of NC-based adducts [Ag29(L)12]L'n3- where n ranges from 1 to 4. This is probed experimentally by using a combination of ultraviolet-visible (UV-vis) spectroscopy, high-resolution electrospray ionization mass spectrometry (ESI MS), and ion mobility mass spectrometry (IM MS) coupled with collision-induced dissociation (MS2 IMS). Density functional theory (DFT) calculations infer comparatively weak noncovalent interactions between the NCs and attached secondary ligands consistent with the fragmentation behavior and experimentally determined collision cross-sections (CCSs), which show a monotonic CCS increase of [Ag29(L)12]L'n3- with an increasing number of L' (n = 1-4). From a detailed analysis of the predicted structures, we infer progressive expansion of the Ag-S staple framework of the precursor NC as secondary ligands are added. Interestingly, detachment of L' from gas-phase [Ag29(L)12]L'n3- by collisional heating yields structures which retain "footprints" of the detached secondary ligands on a millisecond time scale.

Protonation-Independent Charge Transport Across Diphenylamine Single-Molecule Junctions.

Amines are one of the most ubiquitous functional groups in molecular junctions; however, the exact regulation of the charge transport through the protonation state of an amine group in the junction backbone remains elusive. We address this question here by designing a diphenylamine molecular backbone and experimentally investigating how protonation of the central amine group affects the charge transport. Our ultraviolet-visible spectroscopy measurements demonstrate the protonation reaction of the diphenylamine compound in the presence of either trifluoroacetic acid or HCl, and we observe a consistent trend of a modestly increased conductance for diphenylamine in the presence of acid, indicating that a protonated amine group in a diphenylamine backbone slightly enhances the electron conduction. We further investigate the charge transport across diphenylamine under a series of applied tip bias voltages between -0.9 to 0.9 V in an electrochemical environment in the absence and presence of acid for determining the frontier molecular orbital alignment with the Fermi level and the coupling coefficient between the molecule and the electrodes. Our finding shows that the highest occupied molecular orbital (HOMO) is the dominating transport channel of the diphenylamine junction, and a modest conductance increase is an outcome of the HOMO resonance energy moving closer to the Fermi level upon protonation of the amine.

Characteristic Wavelength Selection and Surrogate Monitoring for UV–Vis Absorption Spectroscopy-Based Water Quality Sensing

Ultraviolet-visible (UV–Vis) absorption spectroscopy for in situ water quality sensing has garnered increasing attention. However, the selection of the characteristic wavelengths for water quality indicators has been underexplored in existing studies, resulting in surrogate monitoring models with low accuracy and high complexity. This research used field data from the Maozhou River in Shenzhen. The accuracy of the surrogate model based on the wavelength selection method is 134.8%, 52.5%, and 13.5% improvement in accuracy compared to the single wavelength method, the PCA method, and the full spectrum method, respectively. We investigate seven characteristic wavelength optimisation algorithms and five machine learning models for surrogate monitoring of five water quality indicators: TOC, BOD5, COD, TN, and NO3-N. The results indicate that the competitive adaptive reweighted sampling (CARS) method for wavelength selection, combined with ridge regression as a surrogate monitoring model, achieved the best performance in this study. The determination coefficient (R2) of the five water quality indicators were 0.80, 0.64, 0.82, 0.97, and 0.96, respectively. The study shows that for watersheds with relatively stable water chemical components, there is no need to use overly complex nonlinear models, and the regression model with characteristic wavelength selection can achieve good prediction results. This study provides detailed technical information on river water quality spectral surrogate monitoring, offering an important practice reference.

Photocatalytic Degradation of Tetracycline Hydrochloride Using TiO2/CdS on Nickel Foam Under Visible Light and RSM–BBD Optimization

This study investigates the photocatalytic degradation of tetracycline hydrochloride (TCH) using a TiO2/CdS composite nanocatalyst synthesized on flexible nickel foam via a dipping–pull method. By comparing the photocatalytic degradation of TCH by TiO2/CdS with different precursor ratios, it was found that TiO2/CdS-1.43% exhibited better photocatalytic degradation performance. The X-ray diffraction (XRD) pattern of the TiO2/CdS composite retains the characteristic peaks of both TiO2 and CdS, indicating the successful formation of the composite. According to the analysis of ultraviolet–visible spectroscopy (UV–Vis), the absorption edge of TiO2/CdS is approximately 530 nm. The transmission electron microscopy (TEM) images show Cd and S evenly, densely distributed in TiO2/CdS, further validating its successful synthesis. X-ray photoelectron spectroscopy (XPS) analysis reveals that Cd and Ti elements exist in the forms of Cd2+ and Ti4+, respectively. TiO2/CdS loading uniformity on the nickel foam was assessed using super-depth microscopy. The removal efficiency of 10 L of 20 mg/L TCH solution achieved 53.89%, respectively, under response surface methodology—Box–Behnken design (RSM–BBD) optimal conditions (28 g catalyst, 325 rpm, pH = 9.04 within 150 min). Furthermore, five successive cycling experiments demonstrated strong stability, with a catalyst loss of only 4.44%. Finally, free radical scavenging experiments revealed that ·O2− radicals are the primary active species. This study highlights the potential of TiO2/CdS composites supported on nickel foam for efficient photocatalytic degradation of antibiotic pollutants in water.

O2 evolution reaction by tri barium-coordinated polyoxometalate as a potential water oxidation catalyst

Recently, earth-abundant compounds can be coordinated to the vacant site(s) of lacunary polyoxometalates as water oxidation catalysts (WOCs). Herein, a new catalyst was synthesized based on potassium salt of tri barium-coordinated polyoxometalate (K9[PW9Ba3O34] (denoted as Ba-POM) by reaction of [PW12O40]3- and BaCl2 at pH = 7.5. The prepared PW9Ba3O37 indicated excellent chemical water oxidation activity in the presence of ceric (IV) ammonium nitrate (CAN) as a sacrificial electron acceptor. The synthesized catalyst was characterized by Ultraviolet-visible spectroscopy (UV-vis), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) techniques. In following, the effect of Ba substitution in the structure of POM unit, the role of oxidation activity in water splitting, and also the effect of temperature and acid conditions were discussed.

Comparative Study of Gemological and Spectroscopic Features and Coloration Mechanism of Three Types of Spodumene

Spodumene is a characteristic mineral in lithium-rich granitic pegmatites, serving both as a valuable mineral resource and an important gem material. This study incorporates three different color varieties of spodumene—pink to violet, yellow-green, and colorless—into a unified research framework. X-ray powder diffraction (XRD), electron probe microanalyzer (EPMA), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, ultraviolet–visible spectroscopy (UV-Vis), and photoluminescence spectroscopy (PL) were employed to systematically analyze the chemical composition, crystal structure, and spectroscopic properties of spodumene. Furthermore, the coloration mechanism and fluorescence emission of the different color samples were investigated and analyzed. The results indicate that the presence and mixed valence states of the transition metals Fe and Mn primarily influence the color and photoluminescence of the three types of spodumene. Mn3+ is the primary color-causing element in pink to violet spodumene, while Fe3+ is the primary color-causing element in yellow-green spodumene. Photoluminescence in all three color varieties is dominated by Mn2+. These findings contribute to a deeper understanding of the color and luminescence mechanisms of spodumene, expanding its potential applications as both a gem material and a luminescent material.

Efficient Carbon-Based Optoelectronic Synapses for Dynamic Visual Recognition.

The human visual nervous system excels at recognizing and processing external stimuli, essential for various physiological functions. Biomimetic visual systems leverage biological synapse properties to improve memory encoding and perception. Optoelectronic devices mimicking these synapses can enhance wearable electronics, with layered heterojunction materials being ideal materials for optoelectronic synapses due to their tunable properties and biocompatibility. However, conventional synthesis methods are complex and environmentally harmful, leading to issues such as poor stability and low charge transfer efficiency. Therefore, it is imperative to develop a more efficient, convenient, and eco-friendly method for preparing layered heterojunction materials. Here, a one-step ultrasonic method is employed to mix fullerene (C60) with graphene oxide (GO), yielding a homogeneous layered heterojunction composite film via self-assembly. The biomimetic optoelectronic synapse based on this film achieves 97.3% accuracy in dynamic visual recognition tasks and exhibits capabilities such as synaptic plasticity. Experiments utilizing X-ray photoelectron spectroscopy (XPS), X-ray diffraction spectroscopy (XRD), Fourier-transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) confirms stable π-π interactions between GO and C60, facilitating electron transfer and prolonging carrier recombination times. The novel approach leveraging high-density π electron materials advances artificial intelligence and neuromorphic systems.

Fabrication of Z-Scheme MIL-125/Ag/BiOBr Heterojunctions with Enhanced Photocatalytic Reduction of Cr6.

Herein, first, MIL-125 samples were synthesized via a hydrothermal method. Then, Ag species were doping on the surface of MIL-125 samples via the photolysis of silver nitrate. Finally, the Z-scheme MIL-125/Ag/BiOBr composite was synthesized via a directed liquid assembly method. The structure, morphology, and optical properties of the prepared samples were investigated via X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopic mapping, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, N2 adsorption-desorption analysis, ultraviolet-visible spectroscopy, photoluminescence spectroscopy, surface photovoltage analysis, transient photocurrent response analysis, electrochemical impedance spectroscopy, and electron spin resonance analysis. Photocatalytic experiments indicated that the photocatalytic Cr6+ reduction efficiency of MIL-125/Ag/BiOBr heterojunctions was 85.7% at pH = 6, which was approximately 5.5 and 2.2 times higher than that using BiOBr and MIL-125 alone, respectively. This performance was attributed to the intimate interfacial contact between MIL-125 and BiOBr and the doping of Ag species, which increased the transfer and separation of photogenerated carriers and inhibited the recombination of electrons and holes. Furthermore, the possible photocatalytic Cr6+ reduction mechanism of the Z-scheme MIL-125/Ag/BiOBr photocatalyst was proposed.

Heterostructure Based of Ti-TiO2(NW)/rGO Hybrid Materials for Electrochemical Applications

This study investigated a hybrid electrode based on titanium/titanium dioxide nanowires/reduced graphene oxide (Ti-TiO2(NW)/rGO) that was developed in two stages. The Ti-TiO2(NW)/rGO was obtained by hydrothermal treatment in a mixed solution of H2O2 and melamine for Ti-TiO2 support, followed by a simple spin-coating deposition method and thermal oxidation in a controlled atmosphere of nitrogen gas (99%). The as-prepared structures of electrodes were characterized using ultraviolet-visible spectroscopy (UV-Vis), X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). In addition, the electrochemical behavior was assessed by cyclic voltammetry (CV) in a 1M HNO3-supporting electrolyte and in the presence of 4 mM K4Fe(CN)6 3H2O to determine the electroactive surface area and apparent diffusion coefficient of the hybrid electrode. The development of the Ti-TiO2(NW)/rGO hybrid electrode provides a sensitive method for photo-electrooxidation of doxorubicin due to exploiting the synergistic and remarkable properties of the nanowires of TiO2 and of reduced graphene oxide (rGO) layer on the electrode surface.

Rapid identification of high-temperature Daqu Baijiu with the same aroma type by UV-VIS sensor of HBT combined with Zn2+

Aim: Baijiu adulteration has always been a hot spot of social concern, especially high-temperature Daqu Baijiu, because of its better flavor quality and high value, it faces a challenge from illegal adulteration of high-grade Baijiu bottles with low-grade Baijiu. Methods: A new ultraviolet-visible spectroscopy (UV-VIS) sensor method based on 2-(2-hydroxyphenyl) benzothiazole (HBT) combined with Zn2+ was constructed. The specific mechanism of light signal change was mainly based on the competitive coordination effect of pyrazines and other nitrogen-containing compounds in high-temperature Daqu Baijiu and small molecular probe HBT on Zn2+ and the excited state intramolecular proton transfer (ESIPT) mechanism of HBT itself. Results: The random forest results showed that the prediction set classification accuracy was improved from 62.37% to 100%. The accuracy of the data driven-soft independent modelling of class analogies (DD-SIMCA) model was between 90% and 100%, indicating that the array sensor had a good recognition effect on the adulteration of the same aroma type of Baijiu. Twelve kinds of Maillard reaction products such as tetramethylpyrazine, 2,6-dimethylpyrazine, and furfural in Baijiu were predicted successfully, and the deviation between the real value and the predicted value was less than 1.8746% ± 1.4515%. Conclusions: This method not only improves the specificity of spectral detection, and the amount of information extracted from Baijiu samples, but also the detection time is shortened to less than 3 min, and the accurate identification of high-temperature Daqu Baijiu with the same aroma type was realized. This method can provide reliable help for the rapid identification of high-temperature Daqu and other precious Baijiu, even traditional fermented food.