Ultraviolet-visible Spectrophotometer Research Articles

Application of green synthetic iron oxide nanocatalyst in biohydrogen production from domestic wastewater.

Hydrogen (H2) is considered to be an energy carrier with high yields in future. Using green nanoparticles as the catalyst to produce H2 from organic wastes is an environmentally friendly and cost-effective approach. This study specifically addresses H2 production biologically from domestic wastewater using dark fermentation process with green nanoparticles in anaerobic condition. In this investigation, acid, alkaline, and heat pre-treated wastewater were utilized as the feedstock and identified that the alkaline pre-treated wastewater was an efficient feedstock for H2 production. The reaction conditions such as pH, time, and nanocatalyst dosage were optimized for the enhancement of H2 production. In addition, the green iron oxide nanoparticles (Fe3O4-NPs) were prepared by sustainable way using Murraya koenigii (curry leaves) with FeSO4 and characterized it using Fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible spectrophotometer (UV-vis), power X-ray diffraction (pXRD), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX), further tested for their 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging performance via in vitro antioxidant activities. This study demonstrates that a maximum production of bio-H2 was obtained (72.8mL/L) with 20mg of nanocatalyst load at alkaline condition (pH 9). The correlation coefficient value was highly significant for biohydrogen production with increasing pH (r = 0.9026) and catalyst dosage (r = 0.9962). The characterization studies confirmed the existence of iron oxide nanoparticles in the green synthesized nanoparticles. The in vitro antioxidant assay showed that Fe3O4-NPs effectively reduces the DPPH radical by significantly releasing H-atoms, thereby confirming that the plant extract functions as reducing/oxidizing agents. The high yield under the dark fermentation method has clearly been attributed to the enhancement in bio-H2 production by using the green Fe3O4-NPs based on M. koenigii.

Preparation and Characterisations of Acrylic Epoxy/Polyethylene Glycol/Graphene Oxide Nanocomposites for Antibacterial Coating Applications

This study addresses the urgent need for antibacterial coatings amid escalating concerns about pathogen contamination on various surfaces, particularly in healthcare settings and public spaces where infection control is critical. The development of durable and effective antibacterial coatings could significantly reduce harmful bacteria transmission and improve overall hygiene standards. Graphene oxide (GO) had exceptional antibacterial properties against a wide spectrum of bacteria. Here, the researchers explored the composite of GO with acrylic epoxy (AE) through the use of polyethylene glycol (PEG) to become AE/PEG/GO tertiary nanocomposites in enhancing GO’s antibacterial efficacy. The objectives of this study were to prepare and characterise AE/PEG/GO nanocomposites and then investigate their antibacterial abilities against escherichia coli (E. coli) and staphylococcus aureus (S. aureus) bacteria. The GO was prepared using the modified Hummers method, which was mechanically stirred with AE and PEG to produce the AE/PEG/GO nanocomposites. This was followed by characterisations of the nanocomposites via ultraviolet-visible (UV-Vis) spectrophotometer, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectrometer and scanning electron microscope (SEM). The nanocomposites were then tested against E. coli and S. aureus bacteria by measuring the diameter of the inhibition zone (DIZ). The results showed that the absorption peak of GO was obtained at a wavelength of 236 nm. The diffraction pattern of the AE/PEG/GO nanocomposites showed amorphous structure with a small and wide peak at 2 around 23°. The IR spectrum of the AE/PEG/GO nanocomposites indicated the presence of –OH, –CH3, –CH2, C=O, C–H, C–O and C=C functional groups. The surface morphology showed well-distributed nanocomposite coating onto glass slides with some micro islands. The nanocomposites exhibited promising antibacterial performance revealing higher efficacy against S. aureus compared to E. coli. This was shown by the performance of AE/PEG/GO coating in inhibiting S. aureus bacteria with 1.55 mm larger DIZ compared to the positive control. However, the AE/PEG/GO coating exhibited smaller DIZ than the positive control with a difference of 3.68 mm in inhibiting E. coli bacteria. This study unveiled a simple and straightforward approach in producing nanocomposites for antibacterial coatings shedding light on their potential applications in safeguarding surfaces against bacterial contamination.

Migration and catalytic viscosity reduction of biochar-based catalyst fluid in heavy oil reservoir pores

The method for reducing heavy oil viscosity through catalysts has remained experimental. Catalyst aggregation in reservoirs is a challenging issue. This study prepares catalyst fluids with both hydrophilic and oleophilic properties and uses dispersants to inhibit aggregation. Stability is assessed using direct observation and an ultraviolet-visible spectrophotometer, with results showing that a dispersant concentration of 0.05 wt. % stabilizes catalyst fluids. Micromodel experiments are conducted to investigate the catalytic performance and dispersion characteristics of catalyst fluids under various conditions. A post-processing method based on the hue, saturation, and value color space for image recognition and error calculation is proposed to analyze the migration and sweeping effects of catalyst fluids. This method involves identifying images captured by a digital camera, calculating area ratios, and determining recognition errors. The results show that catalyst fluids exhibit the best viscosity reduction ratio (80.0%) and the largest dispersion area ratio (55.7%) when the catalyst concentration is 4 wt. %, the injection velocity is 0.01 ml/min, the reaction temperature is 200 °C, and the reaction time is 24 h. With the increase in injection velocity, the viscosity reduction effect becomes worse. The viscosity reduction effect is improved with the increase in reaction temperature. With the growth of reaction time, the viscosity reduction effect increases and then becomes gentle. The combined mechanism of catalytic viscosity reduction and sweeping effects of catalyst fluids in porous media is proposed. This study provides a theoretical foundation for the large-scale development of heavy oil catalytic viscosity reduction.

Utilizing DNA Logic Device for Precise Detection of Circulating Tumor Cells via High Catalytic Activity Au Nanoparticle Anchoring.

As medical advancements turn most cancers into manageable chronic diseases, new challenges arise in cancer recurrence monitoring. Detecting circulating tumor cells (CTCs) is crucial for monitoring cancer recurrence, but the current methods are cumbersome and costly. This study developed a new CTC detection system combining DNA aptamer recognition, hybridization chain reaction (HCR) technology, and DNA logic devices, enabling the one-step recognition of CTCs by identifying multiple membrane proteins. After catalytically active Au nanoparticles were attached through reduction synthesis in situ onto the DNA hybridization strands of the CTCs surface, a 3,3',5,5'-tetramethylbenzidine (TMB) colorimetric reaction was used to detect CTCs concentration via peroxidase-like catalysis. With this CTCs detection reporting system, we achieved an LOD of 4 cells/mL using an ultraviolet-visible (UV-vis) spectrophotometer. At certain concentrations, CTCs could even be detected visually without the need for an instrument. The development of this CTCs detection reporting system provided a convenient, reliable, and cost-effective detection strategy for widespread CTCs-based cancer recurrence monitoring.

Extraction and characteristic properties analyses of sodium alginate derived from the Sargassum oligocystum brown seaweed alga of the Bay of Bengal

Sodium alginate extracted from Sargassum oligocystum brown seaweed alga is an important blue economy development process of the Bay of Bengal. In the present study, sodium alginate was extracted from the brown seaweed alga collected from the Cox’s Bazar coastal area of the Bay of Bengal. The extracted product was characterized with the Ultraviolet-visible (UV–visible) spectrophotometer, Fluorescence spectrophotometer, Fourier transform-infrared radiation (FT-IR) spectrophotometer, X-ray diffractometer (XRD), and Scanning electron microscope (SEM). The product yield was optimized with different pH levels and the maximum yield was obtained at 32.5 % at pH 10.96. The moisture, and ash content of the extracted product was measured and found at 13.25 % and 4.35 %, respectively. The viscosity of the extracted product was obtained at 60.1 mPs. The UV–visible spectrophotometry showed different absorbance peaks found at 234 nm, 240 nm, 250 nm, and 264 nm which assigned the extracted product of sodium alginate, and the maximum absorption peak lies at 276.7 nm which assigned flavonoids, and their derivatives of alginates. The fluorescence spectrophotometry demonstrated a strong emission peak at 460 nm with higher intensity (200), indicating the presence of sodium alginate. The FTIR showed the characteristic peaks that demonstrated different functional groups of sodium alginate. The XRD pattern demonstrated 0.24 crystalline indexes indicating the semi-crystalline product in nature. SEM showed clear fibrils of sodium alginate morphology indicating the absence of impurity materials.

Influence of Ta2O5 nanoparticles on the polyvinyl alcohol films’ structure and optical parameters for UV shielding applications

Our current objective is to develop a pioneering system utilizing polyvinyl alcohol (PVA) as a host matrix for the Ta2O5 nanoparticles for shielding applications. The PVA-Ta2O5 films were obtained via casting and characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR), and a polarized optical microscope. XRD and FTIR analyses showed the incorporation of Ta2O5 nanoparticles in the PVA matrix and the change in the polymeric film structure. The optical bandgap energy of the PVA was affected by the inclusion of Ta2O5 nanoparticles and was investigated through Tauc's relation using the absorption data recorded from the ultraviolet–visible spectrophotometer. The direct/indirect bandgaps decreased from 5.37/4.51 eV to 3.52/2.24 eV for PVA undoped and PVA after doping with 5.7 % Ta2O5, respectively. Moreover, the refractive index of the polymer film increased from 1.9148 for pure PVA to 2.3347 after 5 % Ta2O5 was added to the PVA. Adding Ta2O5 nanoparticles to the PVA film improves PVA's optical parameters, qualifying it for use in many optical applications.

Synthesis of Mesoporous ZnO•SiO2 Nanocomposite from Rice Husk for Enhanced Degradation of Organic Substances Including Janus Green B under Visible Light

Rice husk (RH) is often mentioned as an agricultural by-product, often used in the pass as fertilizer and for raw burning. With modern science, RH have been researched and found many new potential benefits and applications. In this study, RH were used to synthesize amorphous SiO2, which was used to prepare the ZnO•SiO2 nanocomposites by a hydrothermal method. The as-synthesized materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and N2 adsorption/desorption isotherm. Their photocatalytic properties were studied by an ultraviolet-vis spectrophotometer and a fluorescence spectrophotometer. The ZnO•SiO2 nanocomposite has an excellent ability to degrade organic substances such as dyes, antibiotics, caffeine, etc. The effects of operating parameters on the photo-degradation reaction progress, including catalyst dosage, initial dye concentration, and pH of the initial dye were investigated in detail. In addition, the photodegradation rate of the dye on the ZnO•SiO2 nanocomposite was evaluated using the pseudo-first-order model. The ZnO•SiO2 nanocomposite can be used as a photocatalyst for wastewater treatment as it detaches much more easily from the solution. Copyright © 2024 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

The addition of Bi2WO6 nanoparticles to polyvinyl alcohol film: Improvements in optical, mechanical, and electrical properties

This study deals with the influence of adding Bi2WO6 (BWO) nanoparticles on the optical, structural, dielectric, and mechanical properties of polyvinyl alcohol (PVA). BWO nanoparticles synthesized by solvothermal method were characterized by X-Ray diffraction (XRD) and scanning electron microscope (SEM-EDS). The thick film nanocomposites were analyzed by Fourier Transformed Infrared (FTIR) spectrometer, XRD device, SEM, atomic force microscope (AFM), ultraviolet visible (UV–Vis) spectrophotometer, impedance analyzer, and tensile test machine. While FTIR analyses confirmed the formation of composite structure and the presence of BWO in the composites, AFM views indicated the reduced roughness for composites. Additionally, the UV–Vis light absorption spectra revealed a narrowed band gap in the composites. Moreover, with increasing BWO contribution, gradual increases were recorded in Young's modulus, toughness and % breaking strain parameters. The frequency dependent dielectric properties was also shown that the energy storage ability of the PVA matrix enhances 25 % and 50 % due to 2 % and 3 % BWO additives, respectively. However, the composite with higher ε′ and lower ε″ values than the pure PVA in the entire frequency range was the 2 % BWO-doped nanocomposite. Based on the serious and simultaneously improvements in electrical, optical and mechanical properties, it can be suggested that 2 % BWO additive provides the opportunity to expand the application area of PVA synergistically.

Performance of yellow and pink oyster mushroom dyes in dye sensitized solar cell

A solar photovoltaic (PV) cell, is an electrical device that uses the PV effect to convert light energy into electricity. The application of oyster mushroom dyes in dye sensitized solar cell (DSSC) is a novel strategy to substitute the costly chemical production process with easily extractable, environmentally acceptable dyes. Both dyes of yellow and pink oyster mushrooms were extracted using the same process but dried into powder form using two techniques, warm drying and freeze drying. The characterization was carried out utilizing current-voltage (I-V) characterization for electrical properties, Ultraviolet-Visible (UV-Vis) spectrophotometer for optical properties, Field Emission Scanning Electron Microscopy (FESEM), and Atomic Force Microscopy (AFM) for the structural properties. It was found that freeze-dried pink and yellow oyster mushroom had shown the good properties for DSSC application as it produced energy bandgap which lies within the range of efficient dye sensitizer; 1.7 eV and 2.2 eV, the most uniform distribution of pores and a nearly spherical form in FESEM analysis, and AFM result obtained with the highest root mean square (RMS) roughness value (26.922 and 34.033) with stereoscopic morphologies. The data proved that mushroom dyes can be incorporated in DSSC with the optimization of drying method in the extraction process, dilution of dye and the layer of deposition on the glass substrate. The current density-voltage (J–V) characteristics of fabricated DSSC was characterized using Newport Oriel Sol3A solar simulator under AM 1.5 Sun condition (100 mW/cm2, 25 oC). From the result obtained by solar simulator, the fabricated FTO/TiO2/Pleurotus djamor dye/Pt indicated the Voc of 0.499 V and Jsc of 0.397 mA/cm2.

Green synthesis of graphene oxide and magnetite nanoparticles and their arsenic removal efficiency from arsenic contaminated soil

Graphene-based nanomaterials have been proved to be robust sorbents for efficient removal of environmental contaminants including arsenic (As). Biobased graphene oxide (bGO-P) derived from sugarcane bagasse via pyrolysis, GO-C via chemical exfoliation, and magnetite nanoparticles (FeNPs) via green approach using Azadirachta indica leaf extract were synthesized and characterized by Ultraviolet-Visible Spectrophotometer (UV-vis.), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), mean particle size and Scanning electron microscopy (SEM) along with Energy dispersive spectroscopy (EDX) analysis. Compared to cellulose and hemicellulose, the lignin fraction was less in the precursor material. The GOC, bGO-P and FeNPs displayed maximum absorption at 230, 236, and 374 nm, respectively. FTIR spectrum showed different functional groups (C-OH, C-O-C, COOH and O-H) modifying the surfaces of synthesized materials. Graphene based nanomaterials showed clustered dense flakes of GO-C and thin transparent flakes of bGO-P. Elemental composition by EDX analysis of GO-C (71.26% C and 27.36% O), bGO-P (74.54% C and 24.61% O) and FeNPs (55.61% Fe, 4.1% C and 35.72% O) confirmed the presence of carbon, oxygen, and iron in synthesized nanomaterials. Sorption study was conducted with soil amended with different doses of synthesized nanomaterials (10, 50 and 250 mg) and exposed to 100, 300 and 500 ppm of As. Arsenic concentrations were estimated by colorimetry and atomic absorption spectroscopy (AAS). GO-C, bGO-P, and FeNPs showed substantial As removal efficiency i.e., 81 to 99.3%, 65 to 98.8% and 73.1–89.9%, respectively. Green synthesis of bGO-P and magnetite nanoparticles removed substantial amounts of As compared to GO-C and can be effectively deployed for As removal or immobilization. Higher and medium sorbent doses (250 and 50 mg) exhibited greater As removal and data was best fitted for Freundlich isotherm evidencing favorable sorption. Nevertheless, at low sorbent doses, data was best fitted for both models. Newly synthesized nanomaterials emerged as promising materials for As removal strategy for soil nano-remediation and can be effectively deployed in As contaminated soils.

Effect of spin coating speeds on electrical and optical characteristic of perovskite SrTiO3 thin films prepared by sol-gel method

The perovskite strontium titanate (SrTiO3/STO) was prepared by the sol-gel process, and the STO thin film was deposited onto a glass substrate by the spin coating method. Effect of different spin coating speeds on the thickness, structural, optical, and electrical properties of the STO thin films was discussed. Five STO films with various spin coating parameters of 2000, 4000, 6000, 8000, and 10000 RPM were prepared. Thickness profilometer tests have shown that the thickness of the STO film changes from 802 nm at 10000 RPM to 1321 nm at 2000 RPM spin coating speed. The prepared STO films morphology was examined by scanning electron microscope. X-ray diffraction measurements have shown that crystalline STO films have been produced with a cubic perovskite structure. The optical properties of the prepared STO films were investigated using an ultraviolet visible spectrophotometer, and the results indicated that the STO film at 8000 and 4000 RPM spin speed show the lowest and the maximum optical band gap (2.83 and 2.90 eV, respectively). All STO films have absorption coefficient values higher than 103 cm−1. The prepared STO thin films had a refractive index between 2.40 and 2.42. The electrical characteristics of the prepared STO films were investigated using the four-point probe method, and it was found that as the spin coating speed increased from 2000 to 8000 RPM, the resistivity of the STO films reduced from 6.629∗1010 to 3.009∗1010 Ω. Moreover, the STO film at 8000 RPM spin speed has the best electrical conductivity (3.301∗10−5 S m−1).

Investigation of The Stability of The Lysozyme in Magnetic Particles for Drug Delivery

This research investigated lysozyme stability in the presence of magnetic particles for drug delivery. Lysozyme can mostly be found in the hen egg albumin, and it also acts as an essential agent, which is antibodies to fight harmful bacteria or shield the human body. The problems in this research are magnetic particles that can cause toxicity and reduce the therapy's efficiency due to the degradation of carriers (drugs). To minimise this problem, the stability and activity of the lysozyme and Fe2O3 were investigated. The structure of lysozyme and Fe2O3 before and after adding acid or alkaline was defined, and the suitability of Fe2O3 as a drug delivery was determined. The stability of the lysozyme and Fe2O3was identified using an Ultraviolet-Visible (UV-Vis) Spectrophotometer, and the structure was investigated using a Field Emission Scanning Electron Microscope (FESEM) and Scanning Electron Microscope- Energy Dispersive X-Ray (SEM-EDX). Different concentrations become the parameters of this research as a comparison between the samples. This research found that the combination of the lysozyme alkaline material was suitable for the body at a pH of 12.2. It also found that Fe2O3 is ideal for drug delivery in the body when the lysozyme can be carried by Fe2O3 and dissolved in the Fe2O3.

Carica papaya L. Latex Mediated Green Synthesis of Zno Nanoparticles for its Antimicrobial Activity

Zinc oxide nanoparticles have gained potential recognition because of their distinctive characteristics and wide utilizatrion in various fields. Therefore, development of novel biological techniques is significant for the biosynthesis of ZnO nanoparticles using the latex of Carica papaya L. Plant latex is a natural product produced by a number of plant species which are used by different tribal communities in India as a folk medicinal treatment on natural wounds or cuts. Plant latex has a huge demand as herbal products in an aspect of clinical, therapeutical and also in agricultural sectors. Natural latex is composed of different important biomolecules like, tannins, flavonoids, glycosides, sterols, saponins etc. These different active chemical constituents have versatile medicinal activities against different pathogens such as bacteria, fungi, viruses and protozoans etc. This study reports on the biosynthesis of ZnO nanoparticles (Zn NPs)using latex of C. papaya as an effective reducing agent. Green synthesis of nanoparticles has advantageous over conventional methodsbecause it does not require the use of toxic chemicals and therefore environmentally sustainable. The elemental composition of C. papaya latex was also analysed using X-ray Fluorescence (XRF) technique. Properties of synthesized ZnO NPs were characterized using various methods such as ultra violet visible spectrophotometer (UV-Vis), scanning electron microscopy and Fourier transform infrared spectroscopy. Green synthesized ZnO nanoparticles also assessed for its antimicrobial activity against selected bacterial and fungal species.

Effects of Spray Adjuvants on Droplet Deposition Characteristics in Litchi Trees under UAV Spraying Operations

In the last decade, unmanned aerial vehicles (UAVs) for plant protection have rapidly developed worldwide as a new method for pesticide application, especially in China and other Asian countries. To improve the deposition quality in UAV applications, adding appropriate types of spray adjuvants into pesticide solutions is one of the most effective ways to facilitate droplet deposition and control efficacy. At present, research on spray adjuvants for UAVs are mainly based on droplet drift and laboratory tests. Few studies have been conducted on the physicochemical properties of spray adjuvants and the effects of droplet deposition characteristics. To explore the properties of four different kinds of spray adjuvants (Mai Fei, Bei Datong, G-2801, and Agrospred 910) and the deposition characteristics of spray adjuvants on litchi leaves, an automatic surface tension meter, a contact angle measuring device, an ultraviolet visible spectrophotometer, and a DJI AGRAS T30 plant protection UAV was used to measure the surface tension, contact angle, and droplet deposition characteristics on litchi under UAV spraying operations. The results showed that the addition of spray adjuvants could significantly reduce the surface tension of the solution. The surface tension value of the solution after adding the spray additives was reduced by 53.1–68.9% compared with the control solution. Among them, the Agrospred 910 spray adjuvant had the best effect on reducing the surface tension of the solution. The contact angle of the control solution on the litchi leaves varied from 80.15° to 72.76°. With the increase in time, the contact angle of the spray adjuvant solution gradually decreased, the Agrospred 910 spray adjuvant had the best effect, and the contact angle decreased from 40.44° to 20.23° after the droplets fell on the litchi leaves for 60 s. The adjuvant solutions increased the droplet size, but the uniformity of the droplet size decreased. The Dv0.5 of different spray solutions ranged from 97.3 to 117.8 μm, which belonged to the fine or very fine droplets, and the Dv0.5 of adjuvants solutions were significantly greater than that of the control solution. The RSs of adjuvant solutions were very similar and ranged from 0.92 to 0.96, all of which were significantly greater than the result of the control solution (0.57). Compared with the deposition of the control solution, the Mai Fei, Bei Datong, and G-2801 solutions clearly increased spray deposition, with total depositions of 0.776, 0.705, and 0.721 μL/cm2, which are all greater than the total deposition of the control solution of 0.645 μL/cm2. The addition of tank-mixed adjuvants could effectively increase the uniformity of the spray deposition, and all the average CVs of adjuvant solutions were lower than 96.86%. On the whole, Mai Fei performed best in increasing the spray deposition and promoting penetration, followed by Bei Datong and G-2801. Meanwhile, the test can also provide a reference for improving the utilization rate of UAV pesticide applications.

Insight into the Structural and Performance Correlation of Photocatalytic TiO2/Cu Composite Films Prepared by Magnetron Sputtering Method

Photocatalysis technology, as an efficient and safe environmentally friendly purification technique, has garnered significant attention and interest. Traditional TiO2 photocatalytic materials still face limitations in practical applications, hindering their widespread adoption. The research prepared TiO2/Cu films with different Cu contents using a magnetron sputtering multi-target co-deposition technique. The incorporation of Cu significantly enhances the antibacterial properties and visible light response of the films. The effects of different Cu contents on the microstructure, surface morphology, wettability, antibacterial properties, and visible light response of the films were investigated using an X-ray diffractometer, X-ray photoelectron spectrometer, field emission scanning electron microscope, confocal laser scanning microscope, Ultraviolet–visible spectrophotometer, and contact angle goniometer. The results showed that the prepared TiO2/Cu films were mainly composed of the rutile TiO2 phase and face-center cubic Cu phase. The introduction of Cu affected the crystal orientation of TiO2 and refined the grain size of the films. With the increase in Cu content, the surface roughness of the films first decreased and then increased. The water contact angle of the films first increased and then decreased, and the film exhibited optimal hydrophobicity when the Cu target power was 10 W. The TiO2/Cu films showed good antibacterial properties against Escherichia coli and Staphylococcus aureus. The introduction of Cu shifted the absorption edge of the films to the red region, significantly narrowed the band gap width to 2.5 eV, and broadened the light response range of the films to the visible light region.

Removal of sulphur and nitrogen compounds from model fuel by adsorption of modified activated carbon

This study aimed to achieve the highest percentage removal of dibenzothiophene (DBT), quinoline (QUI), and indole (IND) adsorbed by double-impregnated modified activated carbon (MAC). Modification of commercial activated carbon (AC) by sulphuric acid (H2SO4) of 15%, 30%, 45%, 60%, and 75% w/v followed by subsequent 1 zinc chloride (ZnCl2): 1 AC impregnation ratio and activated at 500 oC in a muffle furnace under self-generated atmosphere for an hour. The determination of optimized MAC was identified through the highest removal rate of DBT, QUI, and IND from adsorption experiments which were analysed using an ultraviolet-visible (UV-Vis) spectrophotometer. It was found that DBT and IND showed a removal high percentage of up to 86.23% and 82.77% respectively by using 75% H2SO4 with ZnCl2 MAC. Meanwhile, QUI favoured 30% H2SO4 with ZnCl2 MAC with a removal percentage of 33.17% which was still higher than unmodified AC. Physical and chemical properties such as the morphological structure, elemental analysis, porosity, pore size, surface functional group, percentage yield, pH, bulk density, content, ash content, and iodine number were studied for the optimized MAC. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy and Fourier transform infrared spectroscopy (FTIR) were used to characterize the MAC. Both MACs showed high percentage yields of 72.08% and 71.13% for 30% and 75% H2SO4 and ZnCl2 MAC respectively. Meanwhile, the pH was between the ranges of 5.36-5.53 for both MACs. Bulk densities were also favourable while the moisture and ash content were within acceptable limits. Iodine numbers for 30% and 75% H2SO4 and ZnCl2 MAC were 857 and 861 mg/g respectively, hence indicating that the MAC achieved high porosity and good adsorption performance. Langmuir, Freundlich, and Temkin adsorption isotherm models as well as pseudo-first order (PFO) and pseudo-second order (PSO) kinetic models were considered for understanding the adsorption mechanisms. The study revealed that DBT, QUI, and IND removal processes, followed the Langmuir adsorption isotherm model with correlation coefficients, R2 of 0.9905, 0.9791, and 0.9964 respectively. Moreover, the adsorption kinetic data of DBT, QUI, and IND provided a better fitting to the PSO kinetic model with R2 of 0.9992, 0.9987, and 0.9998 respectively. According to the Langmuir isotherm model and PSO kinetic model, the adsorption mechanisms of DBT QUI and IND were chemisorbed under monolayer formations.

An investigation of the enzymatic oligomerization of nitro-substituted phenylene diamine: Thermal and fluorescence properties

2-nitro-p-phenylenediamine, an aromatic diamine, was studied for its oxidative oligomerization with H2O2 using enzyme-catalyzed oligomer synthesis. Characterization of molecular structures was performed utilizing ultraviolet-visible (UV-Vis) spectrophotometer, Fourier-transform infrared spectroscopy (FT-IR), and nuclear magnetic resonance (NMR) techniques, identifying phenazine-bridged oligomer resulting from the enzymatic oligomerization process. Based on the results of gel permeation chromatography (GPC) analysis, the synthesized compound was identified as being in an oligomeric form. Conversely, the number of repeating units, as determined by Mw, was found to be 28. The solvent effect on the optical features of the synthesized oligomer in polar solvents was analyzed. The degradation of phenazine-type structures in the oligomer occurred at higher temperatures than that of the monomer. Under visible light excitation, the oligomer exhibited green light emission with a quantum yield (QY) of 6.2% in N,N-dimethylformamide (DMF). 2-nitro-p-phenylenediamine was readily oxidized into an oligomer with ortho-coupled constitutional units, having a lower electrochemical band gap than the monomer, via the enzymatic oligomerization route. Scanning electron microscopy revealed that enzyme-catalyzed oxidation of monomers exhibited a spongy morphology with some pores

Induction of Tanshinone IIA Production in the Endophytic Fungus Emericella foeniculicola TR21 From Salvia miltiorrhiza Bunge

Background: Tanshinone IIA is effective in the treatment of various cardiovascular diseases. Currently, tanshinone IIA is primarily derived from the roots and rhizomes of Salviamiltiorrhiza Bunge. However, resources of S.miltiorrhiza are already facing scarcity. Objectives: The aim of this study was to obtain an alternative and high-yield mutagenic strain of tanshinone IIA, thus establishing a cost-effective and non-plant-derived substitute for tanshinone IIA. Methods: The mutants with enhanced tanshinone IIA production were selected through protoplast mutation induced by ultraviolet radiation (UV) and sodium nitrite (NaNO2). The yield of tanshinone IIA (YT) was determined using a TU-1810 ultraviolet-visible (UV/Vis) Spectrophotometer and LC-2010A high-performance liquid chromatography (HPLC). The selected mutant strains with the highest yield were subjected to continuous cultivation, and the dry weight of mycelium (DW) and the YT in the first generation were used as controls to assess passage stability. Fungal genomic DNA from the wild-type and mutant strains was extracted from axenic cultures using the modified cetyltrimethyl ammonium bromide (CTAB) method. Results: The colony morphological characteristics exhibited significant differences between the wild-type TR21 and the mutant NU204. The NU204 demonstrated a significantly higher tanshinone IIA yield at 165 ± 2.52 μg/g, which was 4.67-fold greater than that of TR21 (P < 0.01), indicating a substantial enhancement in NU204 production compared to TR21. The NU204 underwent continuous cultivation for five generations, and there were no significant differences in the DW and YT among the different generations (P > 0.05). The observed genetic changes between TR21 and NU204 were induced by the protoplast mutation. Conclusions: The mutant NU204 is emerging as a promising novel alternative source for tanshinone IIA, offering potential practical applications in production.

Aggression to Biomembranes by Hydrophobic Tail Chains under the Stimulus of Reductant.

Stimulus-responsive materials hold significant promise for antitumor applications due to their variable structures and physical properties. In this paper, a series of peptides with a responsive viologen derivative, Pep-CnV (n = 1, 2, 3) were designed and synthesized. The process and mechanism of the interaction were studied and discussed. An ultraviolet-visible (UV) spectrophotometer and fluorescence spectrophotometer were used to study their redox responsiveness. Additionally, their secondary structures were measured by Circular Dichroism (CD) in the presence or absence of the reductant, Na2SO3. DPPC and DPPG liposomes were prepared to mimic normal and tumor cell membranes. The interaction between Pep-CnV and biomembranes was investigated by the measurements of surface tension and cargo leakage. Results proved Pep-CnV was more likely to interact with the DPPG liposome and destroy its biomembrane under the stimulus of the reductant. And the destruction increased with the length of the hydrophobic tail chain. Pep-CnV showed its potential as an intelligent antitumor agent.

A photoelectrochemical sensor based on polydopamine membrane-coated CdS@C core-shell heterostructure for curcumin detection

Curcumin has been widely employed in various fields, but excessive intake may cause tissue necrosis and pose a serious threat to people’s lives and health. Hence, it is crucial to rapidly and precisely detect the content of curcumin. In present research, CdS@C heterostructure materials were successfully prepared through a one-pot solvothermal reaction strategy, utilizing glucose as the carbon source. Simultaneously, polydopamine thin films (ePDA) were successfully deposited on the surface of CdS@C-modified electrodes by the cyclic voltammetry (CV) method. A photoelectrochemical sensor based on the polydopamine membrane-coated CdS@C core–shell heterostructure (ePDA/CdS@C) was designed for curcumin detection. Furthermore, scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible spectrophotometers (UV-vi) techniques were applied to characterize the structure and morphology of the synthesized photoelectric materials. The ePDA coating enhances the stability of the CdS@C material, and the CdS@C core-shell heterostructure accelerates electron transfer. Consequently, the ePDA/CdS@C material generates an outstanding and steady photocurrent response. Under ideal conditions, the novel sensor exhibits a satisfactory linear response to curcumin detection within the concentration range of 0.025–370 μM, with a detection limit as low as 0.0165 μM. Additionally, the ePDA/CdS@C-based photoelectrochemical aptasensor displays remarkable reproducibility, stability, and selectivity. This innovative sensing platform accurately detects curcumin in human serum and urine samples, with an excellent recovery range (99.47 %–103.60 %) and relatively low RSD values (1.49 %–3.56 %). In conclusion, this work offers a novel approach for curcumin detection.