Assisted Method Research Articles

Improved selectivity of electrochemical aniline sensing using one-dimensional silver nanorods with high aspect ratio synthesized by ascorbic acid assisted method

BackgroundAniline serves as a pivotal precursor in many industries such as pesticides, pharmaceuticals, and chemicals. However, its ingestion can lead to severe health consequences, including the potential to induce cancer, respiratory tract irritation, and adverse effects on the nervous and digestive systems in the human body. The widespread use of aniline in industrial processes, coupled with inadequate wastewater management that allows for the direct release of aniline into the environment, leads to surface and groundwater contamination. Therefore, it becomes crucial to devise a reliable electrochemical sensor capable of detecting even trace amounts of aniline. ResultsThis study presents a modified polyol synthesis method for producing silver nanorods (AgNRs, length: 861–1345 nm, diameter: 66–107 nm) with preferential growth along the (111) crystal plane. Immobilizing AgNRs on a glassy carbon (GC) electrode with Nafion as a binder decreases its charge transfer resistance from 3040 to 129 kΩ and increases its electroactive area from 0.034 to 0.101 cm2. AgNRs/GC electrode exhibited an aniline detection limit of 0.032 μM and sensitivity of 1.4841 μA.M−1cm−2 within a linear range of 0–10 μM using square wave voltammetry (SWV). The reaction rate constant of aniline sensing was determined to be 0.08697 s−1. Chlorobenzene, acephate, and chlorpyrifos could not interfere aniline detection, and 26 % decrease in peak response was observed after the 10th cycle of aniline sensing. The sensor demonstrated ∼100 % recovery for aniline, comparable to the performance of high-performance liquid chromatography when applied to real-world samples like tap and river water. SignificanceThe electrochemical sensing of aniline is notably efficient in tap and river water within the acceptable limit, by utilizing one dimensional AgNRs functionalized GC electrode. Importantly, the presence of interferents does not compromise the sensitivity of the sensor. Therefore, one dimensional AgNRs synthesized via a modified polyol route emerge as a promising electrocatalyst for the in-situ detection and determination of aniline.

Effect of assisted drying methods on the microstructure and related quality attributes of fried chicken nuggets

The potential for reducing oil uptake by applying aided pre-drying techniques (microwave, infrared, and convective hot air) was studied on chicken nuggets. Convective hot air (60, 80, and 100 °C); microwave (20, 40, and 60 W); and infrared (150, 250, and 400 W) drying techniques were used to pre-treat chicken nuggets between 1 and 11 min based on preliminary study before frying at 170 °C for 3 min. Standard laboratory methods were employed to assess the quality attributes of fried chicken nuggets, including oil and moisture content, colour, and texture. By comparing the micrographs obtained from chicken nuggets pre-dried using the three pre-dried methods (Microwave, conventional hot air and infra-red), chicken nugget pre-dried using microwave at 60 W have lesser oil cracks (18.05 %) when compared to the rest pre-dried method.Pre-drying substantially lowers moisture content, with microwave pre-drying being most effective, particularly at higher power levels (19.38 ± 1.36–43.11 ± 0.10). Microwave pre-drying densifies the nugget structure, reducing oil absorption during frying (13.15 ± 0.13–28.38 ± 0.12). Microscopic examination of chicken nuggets pre-dried using three methods (microwave, conventional hot air, and infra-red) reveals that those pre-dried with a microwave at 60 W exhibit fewer oil cracks (18.05 %) compared to the other pre-drying methods. It also affects (p < 0.05) the nugget colour, with higher power levels and longer drying times resulting in a darker (10.12 ± 0.01–25.29 ± 0.15) and less yellow nuggets. Texture is also significantly (p < 0.05) affected, with higher power levels and longer drying times leading to increased hardness and chewiness (158.20 ± 1.49–438.14 ± 1.89; 88.00 ± 0.93–165.79 ± 0.86; 96.20 ± 1.44–210.60 ± 0.45). Based on the findings, microwave pre-drying at 60 W for 11 min is recommended for achieving low oil content while maintaining good internal structure in fried chicken nuggets.

Environmental Fate and Dietary Risk Assessment Associated with Triafamone, Ethoxysulfuron and Their Metabolites in Rice Ecosystem

ABSTRACT Triafamone and ethoxysulfuron are ALS inhibitor herbicides belonging to sulfonamide and sulfonylurea group of herbicides used for control of weeds in rice ecosystem. Considering the environmental risk of these herbicides, the fate of triafamone and ethoxysulfuron was assessed to understand the best use of these herbicides. Degradation studies were carried out under field conditions in direct seeded rice (DSR) and transplanted rice (TPR) at an application rate of 67.5 and 135 g ha−1 and adsorption-desorption studies were carried out using batch equilibration technique. Residues of triafamone, ethoxysulfuron and their metabolites were extracted by ultrasonic assisted extraction method from soil and rice grain samples and liquid liquid extraction from straw samples and quantified using HPLC. Degradation half-life (DT50) of triafamone varied from 13.02–20.93 and 12.09–14.67 days under DSR and TPR conditions, respectively while for ethoxysulfuron DT50 ranged from 11.71–15.64 and 9.90–12.19 days. Among both the herbicides, triafamone was more persistent in the soil and at harvest, concentrations of triafamone and ethoxysulfuron in soil and rice were below the acceptable limit (<0.01 mg kg−1) imposed by principal regulatory agencies. Appearance and persistence of studied metabolites corroborated the degradation of parent molecule. Hazard quotient (HQ) of triafamone and ethoxysulfuron was 0.0013 and 0.000657 suggesting that application of these herbicides was safe for use in rice. Triafamone and ethoxysulfuron had a transient effect on soil biochemical and microbiological parameters depending on herbicide dose and moisture conditions. Freundlich adsorption coefficient (Kf) was 1.81 and 1.06 µg1–1/ng−1ml1/n for triafamone and ethoxysulfuron, respectively. GUS index for triafamone and ethoxysulfuron were 1.4 and 2.0 indicating low and moderate mobility, respectively. Principal component analysis (PCA) indicated that ethoxysulfuron has higher leachability than triafamone. Low to moderate persistence, adsorption and leaching of triafamone and ethoxysulfuron and transient ecological impacts on soil microorganisms may pave the way for safe and efficient weed control in rice cultivation.

In-situ formation of Zn-MOF coating on MgO/HA composite layer produced by plasma electrolytic oxidation on Mg-Sn-Mn-Ca alloy for orthopedic internal fixation devices

ABSTRACT A novel ultra-sound assisted method was used to grow zinc-metal organic framework (Zn-MOF) film on magnesium oxide/hydroxyapatite (MgO/HA) composite layer developed using plasma electrolytic oxidation (PEO) on Mg-5Sn-0.2Mn-0.2Ca alloy. The microstructure surface roughness and microhardness tests were performed on the samples to evaluate the mechanical properties of the coatings. The electrochemical corrosion test was performed to evaluate the corrosion resistance of the coated Mg alloy. Further, an in-vitro bioactivity test was performed to study the biocompatibility and bioactivity of the coated alloy, which is an essential aspect of biomedical applications. Results showed that the MgO/HA composite coating was helpful in the in-situ growth of the Zn-MOF particles by mechanically interlocking them. Further, incorporating hydroxyapatite in the coating could also increase the bioactivity. The study also confirmed that the bi-layer coating of Zn-MOF on the MgO/HA composite layer improved the surface roughness, hardness, biocorrosion resistance, and bioactivity making it more likely to be used for orthopedic internal fixation devices.

Use of MRI Radiomics Models in Evaluating the Low HER2 Expression in Breast Cancer.

To investigate the magnetic resonance imaging (MRI) radiomics models in evaluating the human epidermal growth factor receptor 2(HER2) expression in breast cancer. The MRI data of 161 patients with invasive ductal carcinoma (non-special type) of breast cancer were retrospectively collected, and the MRI radiomics models were established based on the MRI imaging features of the fat suppression T2 weighted image (T2WI) sequence, dynamic contrast-enhanced (DCE)-T1WIsequence and joint sequences. The T-test and the least absolute shrinkage and selection operator (LASSO) algorithm were used for feature dimensionality reduction and screening, respectively, and the random forest (RF) algorithm was used to construct the classification model. The model established by the LASSO-RF algorithm was used in the ROC curve analysis. In predicting the low expression state of HER2 in breast cancer, the radiomics models of the fat suppression T2WI sequence, DCE-T1WI sequence, and the combination of the two sequences showed better predictive efficiency. In the receiver operating characteristic (ROC) curve analysis for the verification set of low, negative, and positive HER2 expression, the area under the ROC curve (AUC) value was 0.81, 0.72, and 0.62 for the DCE-T1WI sequence model, 0.79, 0.65 and 0.77 for the T2WI sequence model, and 0.84, 0.73 and 0.66 for the joint sequence model, respectively. The joint sequence model had the highest AUC value. The MRI radiomics models can be used to effectively predict the HER2 expression in breast cancer and provide a non-invasive and early assistant method for clinicians to formulate individualized and accurate treatment plans

Bionanocomposites preparation by design: Planning based on the modification of ceria nanoparticles by polydopamine interleaved with the chitosan biopolymer

Herein, the marine source polymer, chitosan (CS), was utilized to fabricate bionanocomposites by mussel-inspired sonochemical assisted method. The surface modified nanofillers as active ingredients were provided by assembling biomimetic polydopamine (PDA) onto the CeO2 nanoparticles through redox polymerization as a surface modification technology. Standard spectroscopic methods were used to characterize the resulting cerium oxide PDA-treated nanoparticles (NPs). CeO2/PDA/CS nanocomposites (NC)s were manufactured using a sonochemical process by inserting nanostructured fillers into the CS polymer matrix. The morphological features and structural characteristics of NCs were considered using field emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and thermogravimetric analysis techniques. It was found that based on the biomimetic PDA layer the hydrogen bond interactions between CS biopolymer functional units with PDA functional units have occurred. Therefore, a pleasant distribution of surface adapted NPs in macromolecular matrix in the form of nanostructured composites was observed.

A semantic reasoning-based emergency rescue assistant decision method for maritime accidents involving chemicals

Maritime accidents involving chemicals (MAICs) constitute a unique category of marine emergency characterized by low frequency, high risk, and complex disposal challenges. These accidents often entail fires, explosions, and pollutant leakage, demanding effective emergency responses. The success of MAICs rescue operations relies on multiple factors, encompassing the structural features of the involved vessel, personnel, cargo, marine environment, and the availability of resources and response procedures. Proficiency in various professional fields, including ship transportation, chemistry, firefighting, and environmental science, is essential for informed decision-making. This paper addresses the need for a standardized description of knowledge in the MAICs emergency rescue decision-making process, aiming to enhance practical application frequency and decision-making efficiency. Employing ontology theory, the approach involves structurally modeling the knowledge of MAICs emergency rescue, constructing an ontology model, and establishing a decision rule base. Validating the proposed method, the emergency response to the “Longqing 1″ accident is examined as a case study, illustrating its potential for supporting MAICs emergency rescue decision-making. The application of ontology theory in this context holds both theoretical and practical significance. It facilitates the sharing, reuse, and expansion of knowledge in the emergency rescue field, providing crucial technical support for intelligent decision-making in MAICs emergencies.

Flexible photodetector for broadband detection using wurtzite phase CuFeS2 nanoparticles

In the realm of electronic devices, a rising demand for flexible and enhanced performance has emerged. Current research predominately centres on optoelectronics and sensors within the flexible devices’ domain. A flexible photodetector, utilizing CuFeS2 (CFS), is crafted on a cellulose paper substrate. Employing the hand printing method, a thin film of CFS on a graphene-based transporting layer is fabricated. The wurtzite phase of the material synthesized using microwave−assisted method is confirmed by X−ray diffraction (XRD) and Raman spectroscopy, with compositional details provided by energy dispersive X−ray analysis. Comprehensive XRD based calculations of size, stress, strain and energy density are conducted using three different models - Uniform Deformation Model, Uniform Stress Deformation Model and Uniform Deformation Energy Density Model. The average particle size, strain and stress from the three different models is found to be 9⋅73 nm, 1⋅35 × 10−3, 55⋅05 MPa along with calculated energy density value of 78⋅421 kJ m−3, respectively. Band gap calculations utilizing diffuse reflectance yielded an optical bandgap of 1⋅23 eV for the CFS thin film. The fabricated photodetector is studied for different illumination wavelengths, 450 nm, 520 nm, 570 nm, 620 nm and 940 nm, to determined device parameters. The optimum rise time, decay time, responsivity, and specific detectivity for wavelength of 520 nm are 6⋅43 s, 7⋅01 s, 0⋅0319 mA W−1 and 1⋅173 × 1010 Jones. The photoresponse of the fabricated device bended to 2⋅5− and 5−mm radii is studied to recognize suppleness. The photoresponse showed the photocurrent decreases with increase of bending. The observed traits under bending switched to initial on flattening the thin film.

The effect of the 13C abundance of soil microbial DNA on identifying labelled fractions after ultracentrifugation

DNA-based stable isotope probing (DNA-SIP) technology has been widely employed to trace microbes assimilating target substrates. However, the fractions with labelled universal genes are sometimes difficult to distinguish when detected by quantitative real-time PCR. In this experiment, three paddy soils (AQ, CZ, and NB) were amended with 0.1% glucose containing 13C at six levels, and DNA was then extracted after a 7-day incubation and subjected to isopycnic gradient centrifugation. The results showed that the amount of labelled DNA was notably related to the 13C-glucose percentage, while the separation spans of 18S rRNA and 16S rRNA genes between labelled and unlabelled treatments became notably clearer when the δ13C values of the total DNA were 90.9, 61.6, and 38.9‰ and 256.2, 104.5 and 126.1‰ in the AQ, CZ, and NB soils, respectively. Moreover, fractionated DNA was also labelled by determining the δ13C values while adding only 5 atom% 13C-glucose to the soil. The results suggest that the optimal labelling fractions were not always those fractions with the maximal gene abundance, and detecting the δ13C values of the total and fractionated DNA was beneficial in estimating the results of DNA-SIP.Key points• Appropriate 13C-DNA amount was needed for DNA-SIP.• Detecting the 13C ratio of fractionated DNA directly was an assistant method for identifying the labelled fractions.• Fractions with the maximal 18S or 16S rRNA gene abundance always were not labelled.

The use of LifeVac, a novel airway clearance device, in the assistance of choking victims aged five and under: Results of a retrospective 10-year observational study

Background: Choking is a leading cause of injury and death among children under the age of five. Despite notable advances in technology, regulations, and education, the prevalence of choking incidents and related fatalities persists as a global issue, demanding the implementation of improved assistance methods. This study aims to assess the efficacy of an innovative airway clearance device, LifeVac, in aiding children aged 5 and under in choking emergencies. Subjects and Methods: LifeVac LLC maintained a comprehensive database of voluntary reports documenting the utilization of their device in choking emergencies over 10 years, collected through a dedicated website. Collected data included the age and sex of the choking victim, preexisting medical conditions, nature of the object causing airway obstruction, whether basic life support protocol was followed before employing the LifeVac, number of pulls required to dislodge the obstructing object, and adverse events. Results: A total of 299 children were reported to have received assistance with the LifeVac device in choking emergencies. The age range of the assisted children varied from 3 days old to 5 years. One hundred and fifty-seven children were boys. There were 19 reports of preexisting conditions. The most common obstructing objects were plastic, mucus, candy, meat, and fruits. The number of pulls required to successfully dislodge the object ranged from 1 to 10. No failures were reported. Conclusions: LifeVac should be considered a valuable complement to standard life support techniques in choking emergencies, particularly for at-risk groups such as children under the age of 5.

Pengembangan Integrasi Budidaya Ikan Lele Dan Tanaman Herbal Di UPR Doa Mandeh

The catfish cultivation business carried out by UPR Doa Mandeh since 2015 still requires support in the form of assistance and training for its development. Meanwhile, the availability of fish seeds in South Sumatra is still very dependent on other regions, such as Lampung, Jambi and West Java. The lack of use of appropriate catfish cultivation technology and the use of commercial feed has an impact on the low production of fish seeds produced. Apart from that, there has been no effort to treat waste water which has the potential to have a negative impact on the surrounding environment. For this reason, community service (PPM) is carried out, which applies lecture materials, research and publications that have been carried out by the proposing team in the form of application of biofloc technology, making liquid fertilizer and cultivating herbal plants. The aim and benefits of carrying out this activity are to develop the catfish cultivation business, increase seed production, utilize waste water from catfish rearing media into liquid fertilizer products that can be used to develop herbal plant cultivation which will ultimately increase the income of cultivators at UPR Doa Mandeh. The activity model is in the form of empowerment, development and assistance which is implemented using counseling, training and technical/production assistance methods. The results of this activity are high survival and growth rates for catfish, water quality is in the optimal range, and the richness of nutrients in wastewater from the biofloc system can be used as liquid fertilizer for herbal plants. Keywords: biofloc; catfish; herbal plants; liquid fertilizer

Enhancing solubility of polymer-loaded febuxostat through ultrasound-assisted microfluidic antisolvent nanoprecipitation: Optimization using Box-Behnken design

Febuxostat (FEB) nanoparticles with the use of poloxamer 407 were prepared using ultrasound assisted microfluidic nanoprecipitation method to enhance febuxostat's solubility and bioavailability. The optimization for this purpose was conducted using the Box Behnken design (BBD) approach. Four factors and three level BBD was used to study the interactive and individual effect of ultrasonic frequency (X1), amplitude (X2), Ultrasound assisted microfluidic reactor (USMR) temperature (X3), and micromixer confluence angle (X4) on selected two responses. Particle size (Y1) and encapsulation efficiency (% EE) (Y2) were the desired responses. The formulated FEB nanoparticles were analyzed by Fourier Transform Infrared Spectroscopy (FTIR) and Transmission Electron Microscopy (TEM). The minimum nanoparticle size, 7.156 nm with 0.22 polydispersity index (PDI) was attained for FEB-loaded polymer nano-sized particles. To investigate the drug release rate (% DR), fast-dissolving tablets of raw FEB and optimized FEB formulation were prepared. A 1.25-fold improvement in FEB solubility rate was experimentally achieved compared to raw FEB. No chemical interaction between the drug and polymer was observed using FTIR. Optimized FEB formulation showed a 92.94 % release rate of the drug in 90 min with 91.70 % EE.

Wet synthesis of magnetically retrievable Mn/Nd co-doped cobalt ferrites for visible light-driven photocatalytic annihilation of azo dye

In this study, a surfactant assisted wet-chemical method was used to synthesize manganese and neodymium co-doped cobalt ferrite [Co1-xFe2-y O4 (x = Mn, y = Nd)]. The co-doping strategy was adopted to enhance the magnetic properties, tune the band gap, and hamper charge–recombination in the spinel ferrite during the photocatalytic application. Different dopant concentrations, namely Mn = Nd = 1.1 %, 2.2 %, 3.3 %, and, 4.4 %, were used to synthesize MNCF-1, MNCF-2, MNCF-3, and MNCF-4 samples, respectively. The pristine (CF) and co-doped samples (MNCF) were characterized via TGA, PXRD, Raman, FTIR, and UV/Vis techniques to examine the impact of co-doping on the various physicochemical and thermal properties. The optical study proposed the MNCF-4 sample with a band gap value of 2.88 eV as most suitable for visible-light harvesting. A dielectric study showed that co-doped ferrite with a higher dopant concentration (MNCF-4) exhibits boosted AC conductivity and substantially decreased leakage current as compared to the bare and co-doped samples. As the concentrations of the co-dopants increase, the coercivity field (Hc) decreases while the remanent magnetization (Mr) and saturation magnetization (Ms) increase. The MNCF-4 material exhibited the highest magnetic properties, ensuring its full and quick magnetic recovery at the completion of the photocatalytic process. In the context of photocatalytic applications, it was observed that the MNCF-4 catalyst exhibited a mineralization rate constant value of 0.016 min−1 for 92.5 % crystal violet (CV) dye. To mitigate the impact of dye sensitization, the photocatalytic efficiency of MNCF-4 material was assessed by using phenol as a representative colourless organic pollutant. The enhanced magnetic properties of the MNCF-4 catalyst enable its complete magnetic recovery and 90.2 % retention of the photocatalytic activities after five reusability tests.

Inhibition of intermetallic compounds using pure Ni or Ni–Al2O3 nanocomposite coating during the ultrasonic-assisted soldering of Mg/Al dissimilar metals

The widespread utilization of lightweight Mg and Al alloys underscores the importance of establishing reliable connections between them. However, joining dissimilar Mg/Al alloys presents challenges, primarily due to uncontrolled formation of intermetallic compounds during the process, leading to weakened joint performance. To inhibit its formation, a Ni or Ni–Al2O3 nanocomposite coating served as a barrier layer during ultrasonic-assisted soldering AZ31 Mg/6061 Al using Sn–3.0Ag–0.5Cu solder. By investigating the impacts of Ni/Ni–Al2O3 composite coating on microstructure, intermetallic compounds formation, and joint performance, we found that the Ni coating partially inhibited Mg diffusion into the solder at 260 °C for 20 min, thus limiting excessive Mg2Sn compound formation and increasing shear strength by approximately 110% compared to uncoated joints. However, with an extension of the holding time to 30 min, block-shaped Mg2Sn compound reemerged as the primary cause of joint failure. Using Ni–Al2O3 composite coating further broadened the process window of Mg/Al soldering, eliminating block-shaped Mg2Sn compound in the joint at 260 °C for 40 min. The incorporation of Al2O3 further enhanced joint properties, with the maximum shear strength of the Mg(Ni–Al2O3)/SAC/Al joint reaching approximately 66.6 MPa, an improvement of 18.3% compared to the joint with Ni coating. This enhancement shifted the fracture position from the Ni/SAC interface to the SAC solder. Additionally, due to grain refinement in the Ni matrix, the microhardness of the Ni–Al2O3 composite coating surpassed that of the Ni coating. A model of Ni/Ni–Al2O3 composite coating preventing intermetallic compounds formation of was proposed. This nanocomposite coating-ultrasonic assisted soldering method effectively avoids the issue of excessive intermetallic compounds formation when joining dissimilar metals.

Electrochemical and transport properties of nickel hexacyanoferrate (KNi[Fe(CN)6]) as potential cathode material for aqueous potassium-ion batteries

Electronic transport properties of the material can give insight into the inherent charge transport mechanism in the material. Here, we report the transport properties and electrochemical performance of potassium-based nickel hexacyanoferrate (KNiHCF) Prussian Blue Analogue (PBA) synthesized via sonochemical assisted co-precipitation method. The transport properties of the compound were studied from 1 Hz to 10 MHz over 223 K to 423 K. The compound exhibited a specific capacity of 88.5 mAh/g at a current density of 2 A/g, making it a good candidate for potassium-ion batteries.

Ultrasound assisted synthesis of CoFe-LDH for the simultaneous electrochemical detection of dopamine and acetaminophen

Herein, CoFe layered double hydroxide composites (CoFe-LDH) were synthesised by a simple ultrasound assisted synthesis method. It has been characterized by scanning electron microscopy (SEM), X-ray diffraction and X-ray photoelectron spectroscopy. CoFe-LDH modified glass carbon electrode was used as dual-function sensors for DA and AP detection. The sensor exhibits a wide detection linear range for DA and AP (2 μM-900 μM), low detection limits (DA: 0.08 μM; AP: 0.37 μM) (S/N = 3). The sensitivity of CoFe-LDH/GCE for DA and AP were 0.54 μA μM−1 cm−2 and 0.55 μA μM−1 cm−2. And it shows good reproducibility, selectivity, and stability. In addition, the sensor demonstrated good recovery rates for the detection of DA and AP in human serum samples.

Uncovering the predictive pathways of lithium and sodium interchange in layered oxides.

Ion exchange is a powerful method to access metastable materials with advanced functionalities for energy storage applications. However, high concentrations and unfavourably large excesses of lithium are always used for synthesizing lithium cathodes from parent sodium material, and the reaction pathways remain elusive. Here, using layered oxides as model materials, we demonstrate that vacancy level and its corresponding lithium preference are critical in determining the accessible and inaccessible ion exchange pathways. Taking advantage of the strong lithium preference at the right vacancy level, we establish predictive compositional and structural evolution at extremely dilute and low excess lithium based on the phase equilibrium between Li0.94CoO2 and Na0.48CoO2. Such phase separation behaviour is general in both surface reaction-limited and diffusion-limited exchange conditions and is accomplished with the charge redistribution on transition metals. Guided by this understanding, we demonstrate the synthesis of NayCoO2 from the parent LixCoO2 and the synthesis of Li0.94CoO2 from NayCoO2 at 1-1,000 Li/Na (molar ratio) with an electrochemical assisted ion exchange method by mitigating the kinetic barriers. Our study opens new opportunities for ion exchange in predictive synthesis and separation applications.

Fluorescence-enhanced Cs2Ag0.3-xNaxZn0.35In1-yCl6:yM double perovskites for multimodal optical anti-counterfeiting

The excellent optical properties of lead-free halide double perovskites (LHDPs) Cs2AgInCl6 are of great importance in the field of anti-counterfeiting encryption. However, the fluorescence quantum yield of the existing Cs2AgInCl6-based materials is relatively low, and the fluorescence color is monochromatic, making it difficult to use in advanced multi-mode anti-counterfeiting applications. In this study, we synthesized Cs2Ag0.3-xNaxZn0.35In1-yCl6:yM (M = Cr/Bi) series LHDPs using an anti-solvent assisted co-precipitation method, improving the optical properties of Cs2AgInCl6-based materials by optimizing their composition. The fluorescence quantum yield of Zn–Na substituted Cr-doped Cs2Ag0.3-xNaxZn0.35In1-yCl6 LHDPs increased from 1.53 % to 82.57 % on the basis of Cs2AgInCl6. The Zn–Na substituted Bi-doped Cs2Ag0.3-xNaxZn0.35In1-yCl6 LHDPs exhibited dual-wavelength fluorescence emission at 407 and 650 nm, and the relative intensity between the two emission wavelengths changed via a change in the Bi doping amount, resulting in a change in the material's luminescence color. The as-synthesized LHDPs could be applied to multi-mode anti-counterfeiting, optical coding information storage, and art decoration applications.

Physicochemical properties and antibacterial activity evaluation of new indigo extract from Baphicacanthus cusia (Nees) Bremek prepared by chemical conversion method

The effect of acidolysis time, hydrochloric acid concentration, ozonization time and pH on the yield of indigo were investigated by single factor experiment using dried leaves of Baphicacanthus cusia (Nees) Bremek (DLB) as raw material. On this basis, the technological condition for preparing new indigo extract (NIE) by directional chemical conversion method was optimized by orthogonal experiment. Then, the physiochemical properties of NIE were analyzed by combustion assay, nitric acid assay, thin layer chromatography identification assay, moisture detection and water-soluble pigment observation assay. Moreover, UPLC-Q-TOF-MS/MS technology was utilized to compare chemical composition difference between the NIE and traditional indigo naturalis (TIN). Finally, NIE emulsion was prepared by ultrasound assisted high pressure homogenization method and its stability, antibacterial activity as well as antibacterial mechanism were evaluated. The experimental results showed that optimum process for preparing NIE were hydrochloric acid concentration of 2 %, ozonization time of 3 min, pH of 7 and acidolysis time of 1 h; Under this condition, the content and yield of indigo in the NIE were significantly improved, which could reach up to 42.6 ± 0.28 % and 2.26 ± 0.04 %, separately. NIE possessed similar physiochemical properties with TIN described in Chinese pharmacopoeia 2020, and had more diverse active ingredients than TIN. The prepared NIE emulsion demonstrated excellent stability, whether at dark or bright place, and no matter at low temperature (4 ℃) or room temperature (25 ℃), the particle size, PDI, pH and indigo content of which displayed little variation. In addition, the NIE emulsion owned good inhibitory activity against S. aureus, and its MIC and MBC values were 40 and 80 μg/mL, respectively. Moreover, NIE emulsion exhibited antibacterial effect by influencing cell membrane integrity, Ca2+-Mg2+-ATPase activity on the cell membrane and intracellular Ca2+ levels of S. aureus. All of above results will lay the foundation for the green and sustainable utilization of Baphicacanthus cusia (Nees) Bremek.

Rapid preconcentration and determination of Co (II) ions in aqueous medium using ultrasound assisted cloud point extraction method

A flame atomic absorption spectrophotometric technique was studied for the preconcentration and determination of of Co2+ ions in trace amounts after ultrasound enhanced enrichment of its 1-(2-pyridylazo)-2-naphthol (PAN) complexes by cloud point extraction. The Co2+ ions were firstly complexed with PAN molecules at pH 4 and the complex transferred to a surfactant (Tergitol NP-7) rich phase with a very small volume under ultrasound waves. The surfactant rich phase was separated and dissolved by 1 mL, 1.0 M HNO3 in ethanol prior to determination of Co2+ concentration by flame atomic absorption spectrophotometry. The optimization steps of ultrasound interaction time, solution pH and surfactant volumes were achieved by response surface methodology (RSM) which is a combination of statistical approaches. Sample volume, PAN concentration and and possible interfering ions were optimized conventionally. The Co2+ ions were extracted only in 150 s at pH 4 quantitatively under optimum conditions (˃95%). The accuracy and validity of developed UA-CPE was granted by employing a certified reference material wastewater UME CRM 1204. The technique was applied to wastewater and natural water with satisfactory results.