Search

Objective: The aim of this study was to evaluate the degree of conversion (%), flexural strength (MPa), elastic modulus (GPa), compressive strength (MPa), Knoop microhardness (KHN), post-gel shrinkage (%) and prediction of ideal concentration of cholesteryl methacrylate (CM) in experimental resins., Methods: Four formulations were manipulated (F): F1, control group, (0 % CM); F2 (15 % CM); F3 (19.8 % CM) and F4 (30 % CM). Bis-GMA and CM percentages were determined using Statistica™ software. For the degree of conversion test, Raman spectroscopy was used. To testing flexural strength, elastic modulus and compressive strength, a universal testing machine was used. For the Knoop microhardness test five indentations were made in each sample. Post-gel shrinkage was determined using the strain gauge method. Statistica™ software processed all data obtained in this study. Results were submitted to one-way ANOVA and Tukey's post hoc tests (α = 0.05)., Results: Better performance was observed for F2 (15 % CM) and F3 (19,8 % CM) for degree of conversion, elastic modulus and post-gel shrinkage. For Knoop microhardness F2 (15 % CM), F3 (19,8 % CM) and F4 (30 % CM) showed higher values than F1 (0 % CM). For flexural strength F1 (0 % CM) and F3 (19,8 %) were similar and F4 showed the lowest values and for compressive strength F1 (0 % CM) showed the highest values. For mixture designs analysis data, concentrations ≤ 25 % of CM would provide better results., Significance: Addition of CM at concentrations lower than 30 % contributed to a significant increase in the degree of conversion, microhardness values, elastic modulus and reduction of post-gel shrinkage., Competing Interests: Declaration of Competing Interest The authors declare that there are professional relationships related to patent applications/registrations, which may be considered as potentially competing interests., (Copyright © 2024. Published by Elsevier Inc.)

This study employs electrochemical and Density Functional Theory (DFT) calculation approaches to investigate the potential of a novel analogue of trimetozine (TMZ) antioxidant profile. The correlation between oxidative stress and psychological disorders indicates that antioxidants may be an effective alternative treatment option. Butylatedhydroxytoluene (BHT) is a synthetic antioxidant widely used in industry. The BHT-TMZ compound derived from molecular hybridization, known as LQFM289, has shown promising results in early trials, and this study aims to elucidate its electrochemical properties to further support its potential as a therapeutic agent. The electrochemical behavior of LQFM289 was investigated using voltammetry and a mechanism for the redox process was proposed based on the compound's behavior. LQFM289 exhibits two distinct oxidation peaks: the first peak, E p1a ≈ 0.49, corresponds to the oxidation of the phenolic fraction (BHT), and the second peak, E p2a ≈ 1.2 V (vs. Ag/AgCl/KCl sat ), denotes the oxidation of the amino group from morpholine. Electroanalysis was used to identify the redox potentials of the compound, providing insight into its reactivity and stability in different environments. A redox mechanism was proposed based on the resulting peak potentials. The DFT calculation elucidates the electronic structure of LQFM289, resembling the precursors of molecular hybridization (BHT and TMZ), which may also dictate the pharmacophoric performance.

Antioxidants are responsible for many beneficial health effects and are highly present in natural products, such as kombucha. Biosensors' development targeting antioxidants and phytomarkers are an active research field. This work aimed to propose a voltammetric polyphenolxidase ( Cordia superba ) biosensor for catechin and total phenolic compounds quantification in kombucha samples. Optimizations were performed on the biosensor of Cordia superba to improve the accuracy and selectivity, such as enzyme-substrate interaction time, analytical responses for different patterns and signal differences with the carbon paste and modified carbon paste electrode. Kombucha probiotic drink samples were fermented for 7 to 14 days at a controlled temperature (28 ± 2 °C). A linear curve was made for catechin with a range of 10.00 to 60.00 µM, with a limit of detection of 0.13 µM and limit of quantification of 0.39 µM. The biosensor proposed in this work was efficient in determining the patterns of phenolic compounds in kombucha.

Growing concerns on free radicals are the oxidative processes associated with physiological damage. The consumption of functional foods and use of plants with antioxidant capacity are widespread. Given the importance of determining antioxidant capacity in relation to the therapeutic effect, this study was aimed at evaluating cinnamon extract ( Cinnamomum sp.) in commercial samples by spectrophotometric and voltammetric methods and assessing the vascular activity of some samples. The spectrophotometric methods performed were DPPH (1,1-diphenyl-2-picrihydrazine), ABTS (2,21-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)), and Folin-Ciocalteu radical sequestration assays. For the electrochemical experiments, a three-electrode system was used, consisting of carbon paste electrode, platinum wire, and Ag/AgCl/KCl sat , representing the working, auxiliary, and reference electrodes, respectively. The electroanalytical methods used were differential pulse, square wave, and cyclic voltammetries. The extracts were prepared in hydroalcoholic solution. A calibration curve with gallic acid was calculated to quantify their equivalent amounts in the analyzed extract. The correlation between the electrochemical approach and the total phenols calculated by the ABTS, DPPH, and Folin-Ciocalteu methods was 0.63, 0.7, and 0.73, respectively, with 1 being an ideal directly proportional correlation. The correlation between spectrophotometric methods was 0.83. A biosensor was developed in a carbon paste electrode using the enzyme laccase, obtained by the fungus Marasmiellus colocasiae . It was observed that the antioxidant profile of the cinnamon samples had an analytical sign improvement of up to 4 times when compared with the electrode without the modification. The samples were analyzed by mass spectrometer, and the main chemical markers found were coumarin, cinnamaldehyde, and eugenol. Pharmacological trials showed that these samples also induce a significant vasorelaxant effect associated to antioxidant potential on vascular injury induced by oxidative stress. Thus, cinnamon showed a high antioxidant capacity, in agreement with the results obtained in other studies, emphasizing its importance as a functional food., Competing Interests: The authors declare that there is no conflict of interest regarding the publication of this paper., (Copyright © 2022 Emily K. G. Moreno et al.)

The binding between anticancer drugs and double-stranded DNA (dsDNA) is a key issue to understand their mechanism of action, and many chemical methods have been explored on this task. Molecular docking techniques successfully predict the affinity of small molecules into the DNA binding sites. In turn, various DNA-targeted drugs are electroactive; in this regard, their electrochemical behavior may change according to the nature and strength of interaction with DNA. A carbon paste electrode (CPE) modified with calf thymus ds-DNA (CPDE) and computational methods were used to evaluate the drug-DNA intercalation of doxorubicin (DOX), daunorubicin (DAU), idarubicin (IDA), dacarbazine (DAR), mitoxantrone (MIT), and methotrexate (MTX), aiming to evaluate eventual correlations. CPE and CPDE were immersed in pH 7 0.1 mM solutions of each drug with different incubation times. As expected, the CPDE response for all DNA-targeted drugs was higher than that of CPE, evidencing the drug-DNA interaction. A peak current increase of up to 10-fold was observed; the lowest increase was seen for MTX, and the highest increase for MIT. Although this increase in the sensitivity is certainly tied to preconcentration effects of DNA, the data did not agree entirely with docking studies, evidencing the participation of other factors, such as viscosity, interfacial electrostatic interactions, and coefficient of diffusion.

This study presents a new polymeric and multielectronic system, the poly-Alizarin Red S (PARS), obtained from the electropolymerization of Alizarin Red S (ARS) dye on an edge-plane pyrolytic graphite electrode (EPPGE) surface. During EPPGE/PARS electrochemical characterization, we identified seven stable and reversible redox peaks in acidic medium (0.10 mol L -1 , pH 1.62 KH 2 PO 4 ), which indicated its mechanisms underlying electropolymerization and electrochemical behavior. To the best of our knowledge, this is the first study to use an EPPGE/PARS electrode to detect oxandrolone (OXA) in artificial urine, where PARS acts as a synthetic receptor for OXA. The interactions of OXA with EPPGE/PARS as well as the properties of PARS were investigated using density functional theory (DFT). Atomic force microscopy (AFM) was used to characterize EPPGE/PARS, and it was found that the PARS polymer formed a semi-globular phase on the EPPGE surface. The limit of detection for OXA found by the sensor was close to 0.50 nmol L -1 , with a recovery rate of approximately 100% in artificial urine. In addition to the application proposed in this study, EPPGE/PARS is a low-cost product that could be applied in several devices and processes, such as supercapacitors and electrocatalysis., (Copyright © 2021 Elsevier B.V. All rights reserved.)

This work details the study of the redox behavior of the drugs cyclobenzaprine (CBP), amitriptyline (AMP) and nortriptyline (NOR) through voltammetric methods and computational chemistry. Results obtained in this study show that the amine moiety of each compound is more likely to undergo oxidation at 1a at E p1a ≈ 0.69, 0.79, 0.93 V (vs. Ag/AgCl/KClsat) for CBP, AMP and NOR, respectively. Moreover, CBP presented a second peak, 2a at E p2a ≈ 0.98 V (vs. Ag/AgCl/KClsat) at pH 7.0. Furthermore, the electronic structure calculation results corroborate the electrochemical assays regarding the HOMO energies of the lowest energy conformers of each molecule. The mechanism for each anodic process is proposed according to electroanalytical and computational chemistry findings, which show evidence that the methods herein employed may be a valuable alternative to study the redox behavior of structurally similar drugs.

Diclofenac (DIC) is a non-steroidal anti-inflammatory drug of wide use around the world. Electroanalytical methods display a high analytical potential for application in pharmaceutical samples but the drawbacks concerning electrode fouling and reproducibility are of major concern. Henceforth, the aim of this work was to propose the use of alternative low-cost carbon black (CB) and ionic liquid (IL) matrix to modify the surface of pencil graphite electrodes (PGE) in order to quantify DIC in raw materials, intermediates, and final products, as well as in stability assays of tablets. The proposed method using CB+IL/PGE displayed good recovery (99.4%) as well as limits of detection (LOD) of 0.08 µmol L-1 and limits of quantification (LOQ) of 0.28 µmol L -1 . CB+IL/PGE response was five times greater than the unmodified PGE. CB+IL-PGE stands as an interesting alternative for DIC assessment in different pharmaceutical samples.

Red fruits are rich sources of antioxidant compounds with recognized health benefits. Since they are perishable, dried extracts emerge as more durable products and their quality control must include antioxidant capacity assays. In this study, the redox behavior of commercial dried products obtained from camu-camu, açai, acerola and cranberry red fruits was evaluated by electroanalytical approaches. The antioxidant potential was determined by 2,2-diphenyl-1-picrylhydrazyl free radical assay and the electrochemical index concept. The total phenol content was estimated by using a laccase based biosensor. A significant correlation was found between all methods and literature data. The voltammetric profile (cyclic, differential and square wave) obtained for each type of dried extract showed distinguishable features that were correlated with their main major markers, being also useful for identification purposes. The electrochemical methods were cheaper and more practical for evaluation of antioxidant properties and total phenol content in dried powders obtained from different red fruits., (Copyright © 2016. Published by Elsevier Ltd.)

Exposure of antimalarial herbal drugs (AMHDs) to ultraviolet radiation (UVR) affects the potency and integrity of the AMHDs. Instant classification of the AMHDs exposed to UVR (UVR-AMHDs) from unexposed ones (Non-UVR-AMHDs) would be beneficial for public health safety, especially in warm regions. For the first time, this work combined laser-induced autofluorescence (LIAF) with chemometric techniques to classify UVR-AMHDs from Non-UVR-AMHDs. LIAF spectra data were recorded from 200 ml of each of the UVR-AMHDs and Non-UVR-AMHDs. To extract useful data from the spectra fingerprint, principal components (PCs) analysis was used. The performance of five chemometric algorithms: random forest (RF), neural network (NN), support vector machine (SVM), linear discriminant analysis (LDA), and k-nearest neighbour (KNN), were compared after optimization by validation. The chemometric algorithms showed that KNN, SVM, NN, and RF were superior with a classification accuracy of 100% for UVR-AMHDs while LDA had a classification accuracy of 98.8% after standardization of the spectra data and was used as an input variable for the model. Meanwhile, a classification accuracy of 100% was obtained for KNN, LDA, SVM, and NN when the raw spectra data was used as input except for RF for which a classification accuracy of 99.9% was obtained. Classification accuracy above 99.74 ± 0.26% at 3 PCs in both the training and testing sets were obtained from the chemometric models. The results showed that the LIAF, combined with the chemometric techniques, can be used to classify UVR-AMHDs from Non-UVR-AMHDs for consumer confidence in malaria-prone regions. The technique offers a non-destructive, rapid, and viable tool for identifying UVR-AMHDs in resource-poor countries. [ABSTRACT FROM AUTHOR]

Differential pulse voltammetry (DPV) and spectrophotometric methods were used to evaluate the antioxidant capacity (AC) in strawberry and orange juice, soluble coffee, rosemary extract, red wine, and sparkling white wine. The AC through spectrophotometric methods showed the following trend in solid foods, coffee > rosemary extract, and red wine > strawberry juice > orange juice > sparkling white wine in liquid samples. Charge measurements by DPV, presented in equivalent units of Trolox and gallic acid, showed the same trend in liquid samples; however, for solid samples, the AC of rosemary extract was greater than that of coffee. The charge expressed in equivalent units showed a high, positive, and significant correlation (p < 0.001) with total phenols (0.7919), FRAP (0.8875), and ABTS (0.8366). The proposed electrochemical technique proves to be a fast, reliable, and environmentally friendly alternative or complement to evaluate antioxidant capacity in food, which is not affected by the turbidity or color of the samples. [ABSTRACT FROM AUTHOR]

In the scope of a research program with the goal of developing treatments for inflammatory diseases, the pharmacological evaluation of LQFM291, designed by molecular hybridization from butylated hydroxytoluene and paracetamol, was described. The antioxidant profile of LQFM291 was evaluated by electrochemical measurement. Also, acute or repeated treatments with equimolar doses to paracetamol were used to evaluate the antinociceptive and/or anti-inflammatory activities of LQFM291 in animal models. The toxicologic potential of LQFM291 was also evaluated and compared to paracetamol through biochemical and histopathological analysis after the repeated treatment schedule. As a result of the acute treatment, paracetamol showed a similar antinociceptive effect in formalin test compared to LQFM291. Whereas, after the repeated treatment, when carrageenan-induced hyperalgesia and edema tests were performed, paracetamol showed a delayed antinociceptive and anti-inflammatory effect compared to LQFM291. Furthermore, as other advantages the LQFM291 showed a high redox capacity, a gastroprotective activity and a safety pharmacological profile without any liver or kidney damage. These effects can be related to the prevention of oxidative stress by reduction of protein and lipid peroxidation in gastric tissue, maintenance of glutathione levels in hepatic homogenate, and a systemic reduction of pro-inflammatory cytokine levels, which may characterize the LQFM291 as a more viable and effective alternative to relief pain and inflammatory signs in patients with chronic disorders. [ABSTRACT FROM AUTHOR]

Turmeric is widely used as a health supplement and foodstuff in South East Asian countries because of its medicinal benefits. Like several other plants and peppers, turmeric is prone to exploitation because of its economic value, rising consumer need, and essential food element that adds colour and flavour. Due to this, quick and comprehensive testing processes are needed to detect adulterants in turmeric. In this study, pure turmeric powders were mixed with starch in proportions ranging from 0 to 50% with a 1% variation to obtain different combinations. Reflectance spectra of pure turmeric and starch mixed samples were recorded using a JASCO-V770 spectrometer from 400 to 2050 nm. The recorded spectra were pre-processed using a Multiplicative Scatter Correction (MSC) and Standard Normal Variate (SNV). The Savitzky-Golay (SG) filter was initially applied to these original (X), MSC, and SNV-corrected spectra. Secondly, the Extra Tree Regressor (ETR) feature selection method was employed to select the best features. Finally, principal component analysis (PCA) was used to reduce the dimension of the selected features. The stacked generalization method was applied to improve the performance of this work. Both regressors and classifier stacking techniques have been tested with different classification and regression methods. The K-Nearest Neighbours (KNN), Decision Tree (DT), and Random Forest (RF) models were used as base learners, and Logistic Regression (LRC) was used as a meta-model for classification and Linear Regression (LR) for regression analysis. The proposed method achieved the best regression performance with r2 of 0.999, Root Mean Square Error (RMSE) of 0.206, Ratio of Performance to Deviation (RPD) of 73.73, and Range Error Ratio (RER) of 480.58, whereas 100% F1 score and Matthew's Correlation Coefficient (MCC) classification performance. [ABSTRACT FROM AUTHOR]

Background: The production of red fruits, such as blueberry, has been threatened by several stressors from severe periods of drought, nutrient scarcity, phytopathogens, and costs with fertilization programs with adverse consequences. Thus, there is an urgent need to increase this crop's resilience whilst promoting sustainable agriculture. Plant growth-promoting microorganisms (PGPMs) constitute not only a solution to tackle water and nutrient deficits in soils, but also as a control against phytopathogens and as green compounds for agricultural practices. Methods: In this study, a metagenomic approach of the local fungal and bacterial community of the rhizosphere of Vaccinium corymbosum plants was performed. At the same time, both epiphytic and endophytic microorganisms were isolated in order to disclose putative beneficial native organisms. Results: Results showed a high relative abundance of Archaeorhizomyces and Serendipita genera in the ITS sequencing, and Bradyrhizobium genus in the 16S sequencing. Diversity analysis disclosed that the fungal community presented a higher inter-sample variability than the bacterial community, and beta-diversity analysis further corroborated this result. Trichoderma spp., Bacillus spp., and Mucor moelleri were isolated from the V. corymbosum plants. Discussion: This work revealed a native microbial community capable of establishing mycorrhizal relationships, and with beneficial physiological traits for blueberry production. It was also possible to isolate several naturally-occurring microorganisms that are known to have plant growth-promoting activity and confer tolerance to hydric stress, a serious climate change threat. Future studies should be performed with these isolates to disclose their efficiency in conferring the needed resilience for this and several crops. [ABSTRACT FROM AUTHOR]

Petroleum products are the target of fraudulent practices due to their high commercial value. The aim of this study is to provide a new analysis system to assess motor oil adulteration. For this purpose, Laser Induced Fluorescence (LIF) spectroscopy was exploited coupled with chemometric tools to detect motor oil adulteration by three types of cheap motor oils. Principal Component Analysis (PCA) was able to distinguish samples in three groups according to the type of adulterant. Besides, Partial Least Squares Regression (PLSR) was exploited to determine the percentage of adulteration. The best model was obtained with a regression coefficient of 0.96, Root Mean Square Error of Prediction (RMSEP) of 2.83, Standard Error of Prediction (SEP) of 2.83 and Bias of 0.40. The main results of this work provide new analysis system using the combination of LIF spectroscopy combined to PCA and PLS as an efficient and fast method for motor oil analysis. [ABSTRACT FROM AUTHOR]

In this work, the development of a disposable electrochemical device (US$ 0.02 per electrode) using a 3D printed support (3Ds) of acrylonitrile butadiene styrene (ABS) insulating filament with a composite material (CM) based on graphite and nail polish, immobilized on the support surface, was described for the electrochemical determination of diclofenac (DCF). The device was compared to the commercial glassy carbon electrode (GCE) and showed superior electroanalytical performance with approximately 1.8-fold higher current density. Additionally, an amperometric method for DCF determination in tap water, synthetic urine, and pharmaceutical formulation samples with the proposed electrode, using a flow injection analysis (FIA-AD) system, was developed. The optimized method presented excellent detectability (LOD = 0.47 µmol L−1), with excellent precision and accuracy (relative standard deviation < 5.6%) and percent recovery from spiked samples ranging from 89 to 106%. In addition, the sensor showed optimal analytical frequency with approximately 108 injections per hour, which demonstrates the potential of this system using the proposed disposable electrode for implementation in routine analysis and quality control with good selectivity and sensitivity. [ABSTRACT FROM AUTHOR]

A nanocomposite of Ce-doped ZnO/r-GO was synthesized using a conventional hydrothermal method. The synthesized nanocomposites were utilized for the purpose of sensitive and selective detection of cyclobenzaprine hydrochloride (CBP). The properties of the composite were extensively analyzed, including its morphology, structure, and electrochemical behavior. This study investigates the application of a modified glassy carbon electrode for the detection of CBP, a muscle relaxant used to treat musculoskeletal diseases that cause muscle spasms. The electrode is modified with Ce-doped ZnO/r-GO. Various detection methods, such as cyclic voltammetric and square wave techniques (SWV), were utilized. The composite material showed high effectiveness as an electron transfer mediator in the oxidation of CBP. The electrode showed a good response for SWV evaluations in CBP identification, with a minimum detection limit of 1.6 × 10 - 8  M and a wide linear range from 10 × 10 - 6 M to 0.6 × 10 - 7 M, under ideal conditions. The rate constant for charge transfer (ks) and the estimation of the electrochemical active surface area were obtained. A developed sensor exhibited desirable selectivity, long-lasting stability, and remarkable reproducibility. A sensor was used to analyze water, human serum, and urine samples, resulting in positive recovery results., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

The physicochemical property of water-insoluble drug piroxicam (PY) in the presence of two. ionic-mixed micellar systems was investigated. The two systems were pluronic L-81-sodium dodecyl sulfate (SDS), a nonionic-anionic; and pluronic L-81-cetyl pyridinium bromide (CPB), a nonionic-cationic. The characterizations employed were UV–visible spectroscopy, FTIR spectroscopy, conductivity, cloud point and cyclic voltammetry measurements. The results from UV spectra showed that there was different behaviour of piroxicam with anionic and cationic mixed micelles. But, the common observation for both sets was that the drug absorption with a mixed micellar system displayed an intermediate position compared to both the single micellar systems. There was short and strong bond formation in the complex formed between piroxicam and mixed micelles as evidenced by FTIR studies. The conductivity measurements revealed that the drug and mixed micelle in the produced complex have a stable and spontaneous binding. The free energy of micellization ∆Gm was observed to be -18.04 kJ/mole for piroxicam [PY + L-81] + SDSa group and -37.73 kJ/mole for piroxicam [PY + L-81] + CPBc group. The higher negative value of the nonionic-cationic system indicates greater stability of the drug in the system. The cloud point measurements corroborated this finding. The cyclic voltammetry study of piroxicam with ionic surfactant SDS/CPB displays greater electrostatic interaction in mixed micelle combination (PY/CPB/L-81) compared to single micelle combination (PY/CPB) and pure drug. The combination is novel for the hydrophobic drug piroxicam which can be used by the formulation scientist. Interaction of drug (PY) and surfactant (SDS/CPB) presence of pluronic L-81 [ABSTRACT FROM AUTHOR]

The versatility of immobilized enzyme systems enables rapid recovery of both product and enzyme, numerous re-uses of enzymes, continuous enzymatic processes, quick reaction termination, and a wider range of bioreactor designs. Immobilized enzymes have been the topic of significant research because of their remarkable functional characteristics such as optimal nature, reusability, and cost-effectiveness. In addition to industrial operations, enzyme immobilization technology is also utilized as component technology in the food industry, biomaterial detection, medical diagnostics, bioenergy, and therapeutics. To demonstrate its important uses, several sorts of biosensors, such as enzyme-based biosensors, enzyme-based thermistors, electrochemical biosensors, optical biosensors, DNA biosensors, immunosensors, magnetic biosensors, and thermal biosensors have been debated here. A flexible and highly functioning enzyme is utilized for analyte identification by oxidizing enzymes such as peroxidases and polyphenol oxidize such as laccases and tyrosinases. These enzymes are therefore regarded as appealing and intriguing compounds for biosensors. New systems of reliable biosensor interfaces have gathered considerable interest in recent years. This study highlights key prospects, the newest technologies and materials utilized to build robust biosensor interfaces. These materials include polymers, nanomaterials and their composites i.e. nanocomposites were used for the designation of biosensors. This review studies recent advances in stability interface solutions for biosensors, which may give researchers some references and novel approaches to further investigate new materials and methodologies in biomedical applications. [ABSTRACT FROM AUTHOR]

Purpose: The development biosensing technologies capable of delivering fast and reliable analysis is a growing trend in drug quality control. Considering the emerging use of plant-based polyphenol oxidases (PPO) as biological component of electrochemical biosensors, this work reports the first Solanum lycocarpum PPO biosensor and its use in the pharmaceutical analysis of paracetamol in tablet formulations. Methods: The biosensor was optimized regarding fruit maturation (immature and mature-ripe), vegetal extract volume to be used in biosensor construction as well as optimal pH of electrochemical cell fluid. Results: Results evidenced that the extract which rendered the biosensor with best analytical performance was from immature fruits, and the biosensor produced using 100 µL of crude plant extract promoted better faradaic signal gathering. Moreover, when neutral pH media was used in the electrochemical cell, the biosensor showcased best faradaic signal output from the used redox probe (catechol), suggesting thence that the method presents high sensibility for phenolic compounds detection. Furthermore, the biosensor was able to quantify paracetamol in a linear range from 50 to 300 µM, showcasing LoD and LoQ of 3 µM and 10 µM, respectively. Conclusion: after careful evaluation, this biosensor might be a low-cost alternative for conventional pharmaceutical quality control methods. [ABSTRACT FROM AUTHOR]

In this paper, a kind of soybean nodule-derived nitrogen-doped carbon (SNNDC) was prepared, characterized and applied to modify the assembled carbon paste electrode (CPE), to fabricate a novel chemical sensor for the detections of AA and DA. The electrochemical characteristics of SNNDC implied that it is an effective electron transfer mediator accelerating the electron transfer to CPE. The cyclic voltammetry measurements at different scan rates indicated that the electrochemical process on the electrode surface of the chemical sensor is a diffusion-controlled irreversible oxidation reaction of one-electron and one-proton for DA, and two-electron with one-proton for AA. The linear detection ranges of the chemical sensor for the detections of AA and DA were 5–3000 μM and 5–1000 μM with the detection limits of 1.90 μM and 3.18 μM, respectively, as determined by amperometric experiments. Both linear detection range and detection limit obtained are comparable or better than those of several modified electrodes reported recently. And the chemical sensor was also successfully applied to the detections of AA and DA in injection samples. This study suggested that the fabricated chemical sensor is a hopeful candidate to be used in the detection of pharmaceutical samples of AA and DA, and provides valuable reference information for the development of novel drug sensors in both clinical laboratory and food industries. [ABSTRACT FROM AUTHOR]

This work reports a "green" method where silver nanoparticles (AgNPs) were synthesized using silver nitrate and the aqueous extract of black currant pomaces (BCPE). LC–MS spectrum showed the presence of 16 compounds with chlorogenic acid and caffeic acid as the dominant components of BCPE. Total phenolic content and total flavonoid content of extracts were determined. Various experimental techniques including iron (III) reducing capacity, total antioxidant capacity, and DPPH radical scavenging activity were used to characterize antioxidant activity of the extract. Scanning electron microscopy (SEM) and EDX analysis showed that silver nanoparticles were pure and polydisperse. The synthesized nanoparticles might serve as a potent antioxidant as revealed by DPPH assay. The synthesized nanoparticles (BCPE–AgNPs) efficiently inhibit pathogenic organisms such as Gram-negative bacteria. [ABSTRACT FROM AUTHOR]

This paper reports the preparation and electrochemical properties of the PbSO4 negative electrode with polyvinyl alcohol (PVA) and sodium polystyrene sulfonate (PSS) as the binders. The results show that the mixture of PVA and PSS added to the PbSO4 electrode can significantly improve the specific discharge capacity of the PbSO4 electrode, which reaches 110 mAh g−1 and survives 700 cycles at full charge and discharge at 100 mA g−1. The mixture of PVA and PSS can also replace the short fibers used in conventional cells, and shortens the activation time of the electrode. [ABSTRACT FROM AUTHOR]