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This study addresses the increasing incidence of scorpion accidents in Brazil, accounting for approximately 54% of cases of venomous animal poisoning. The lack of rapid diagnosis poses a significant challenge for the treatment of envenomed patients. The study aims to develop agile and sensitive detection methods to enable specific and efficacious treatments. A label-free biosensor, notably an impedimetric immunosensor for detecting Tityus serrulatus venom, was developed with disposable screen-printed electrodes made of carbon and silver ink, biofunctionalized with antibodies through the self-assembled monolayer (SAM) technique. The antigen capture immunosensor demonstrated robust analytical performance in buffer solution, with a wide linear range (LR) ranging from 0.1 to 10,000 ng/mL. The venom concentration of 1 ng/mL was used to address parameters such as sensitivity, selectivity, linearity, and reproducibility. The technological evolution indicated in this study suggests that the immunosensor has the potential to be integrated into everyday medical practices. [ABSTRACT FROM AUTHOR]

Biofilm formation is a widespread phenomenon that impacts different fields, including the food industry, agriculture, health care and the environment. Accordingly, there is a serious need for new methods of managing the problem of biofilm formation. Natural products have historically been a rich source of varied compounds with a wide variety of biological functions, including antibiofilm agents. In this review, we critically highlight and discuss the recent progress in understanding the antibiofilm effects of several bioactive compounds isolated from different plants, and in elucidating the underlying mechanisms of action and the factors influencing their adhesion. The literature shows that bioactive compounds have promising antibiofilm potential against both Gram-negative and Gram-positive bacterial and fungal strains, via several mechanisms of action, such as suppressing the formation of the polymer matrix, limiting O2 consumption, inhibiting microbial DNA replication, decreasing hydrophobicity of cell surfaces and blocking the quorum sensing network. This antibiofilm activity is influenced by several environmental factors, such as nutritional cues, pH values, O2 availability and temperature. This review demonstrates that several bioactive compounds could mitigate the problem of biofilm production. However, toxicological assessment and pharmacokinetic investigations of these molecules are strongly required to validate their safety. [ABSTRACT FROM AUTHOR]

This paper introduces a new approach for performing package classification and sizing using Radio-Frequency Identification (RFID) systems. This technique is applicable when packages are labeled with or contain multiple RFID-tagged items. During the interrogation of the tags, received signal strength (RSS) statistics and other information, such as the frame count or the reading time, are collected by the reader and used to predict the package type from a set of candidate classes using an Artificial Neural Network (ANN). The primary challenge lies in acquiring sufficient training data for a target scenario to ensure reliable predictions. To address this, a two-phase training process based on transfer learning is adopted. Initially, a base model is developed using synthetic data generated from a detailed RFID simulator, designed to suit diverse scenarios, establish detailed link budgets, and comprehensively simulate the communication protocols. This model is then refined using a small dataset collected experimentally in the actual scenario. This method was validated in a real testbed with four different package types. The base model was trained using 1000 synthetic samples per package type (4000 in total), whereas the refined model was trained with a dataset consisting of only 25 real interrogation traces (samples) per package type (100 in total). The experimental samples were obtained using a software-defined radio unit, the Ettus B210 Universal Software Radio Peripheral (USRP) platform. This experiment achieved an accuracy of over 92%. In summary, this approach introduces a new feature to existing RFID setups, demonstrating potential for advanced package handling and cost optimization in the logistics sector. [ABSTRACT FROM AUTHOR]

Radio frequency (RF) systems tend to become congested and overused due to the increasing number of users, devices and the multiple technologies involved in their deployment. This leads to the downgrading of quality of service (QoS) further caused by interference with different signals. Optical Wireless communications (OWC) are emerging as a feasible alternative as they offer unlicensed, interference-free spectrum by using the frequency range located in the visible and invisible light spectrum. Its applications can be found in various fields such as healthcare, education, finance and industry 4.0. Moreover, it enhances the security and privacy of communications. Nevertheless, the limited spectrum in OWC also requires optimised resource allocation to support the QoS of different applications or users whilst lacking established infrastructure to manage this. To address these challenges, this paper proposes a novel 5G-LiFi framework able to ensure QoS requirements by introducing network slicing in Light Fidelity (LiFi) networks integrated with 5G infrastructure. This paper has developed and deployed a 5G-LiFi architecture capable of providing network slicing capabilities over the LiFi segment of the hybrid network. It allows a full control over the network traffic and tailored, improved QoS capabilities. The proposed solution has been empirically validated and evaluated in a realistic testbed employing real-world LiFi and 5G network equipment, and yielded promising results in terms of bandwidth, delay, jitter and packet loss. This work concludes that the use of heterogeneous networks integrating OWC with RF is a suitable solution and it can lead to a better use and exploitation of the different spectrums, improving the QoS offered to end-users. [ABSTRACT FROM AUTHOR]

Neochlorogenic acid, a less-studied isomer of chlorogenic acid, has been seen to posses antioxidant, antifungal, anti-inflammatory and anticarcinogenic effects, which makes it an interesting candidate for incorporation in functional foods. However, its poor solubility in water and susceptibility to oxidation make such a task difficult. To overcome that, its encapsulation in cyclodextrins (CDs) is proposed. The fluorescence of neochlorogenic acid in different pH conditions was analyzed, and caffeic acid was proved to be the fluorescent moiety in the molecule. An encapsulation model whereby the ligand poses two potential complexation sites (caffeic and D-(-)-quinic moieties), showed that α-CD and HP-β-CD formed the best inclusion complexes with neochlorogenic acid, followed by M-β-CD, β-CD and γ-CD. Molecular docking with the two best CDs gave better scores for α-CD, despite HP-β-CD providing stabilization through H-bonds. The encapsulation of chlorogenic acid led to a similar CD order and scores, although constants were higher for α-CD, β-CD and M-β-CD, lower for HP-β-CD, and negligible for γ-CD. The protonation state affected these results leading to a different order of CD preference. The solubility and the susceptibility to oxidation of neochlorogenic acid improved after complexation with α-CD and HP-β-CD, while the antioxidant activity of both isomers was maintained. [ABSTRACT FROM AUTHOR]

An easy and effective method for the preparation of a new impedimetric sensor used in the detection of dimethyl sulfide (DMS) at a nanomolar level is presented. The sensor was prepared in two steps from a commercially available screen-printed carbon electrode (SPCE): a simple activation of the SCPE using cyclic voltammetry followed by electroless plating of the working electrode surface with gold clusters. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) techniques confirmed the successful functionalization of the SPCE, revealing the presence of gold particles dispersed on the carbon matrix. Electrochemical impedance spectroscopy (EIS) was used to study the sensitivity of the sensor towards DMS dissolved in aqueous solution and simulated ocean water. Analyses were performed in less than 3 min, and the sensor showed linearity in a concentration range from 1.0 × 10−10 to 1.0 × 10−8 M with a limit of detection of 1.50 × 10−9 M and a limit of quantification of 2.27 × 10−9 M. To simulate the marine environment in which DMS is naturally present in nature, the impedance of the sensor was monitored by online EIS. Moreover, results indicated that, despite not linearly, the sensor is a promising tool to detect the analyte even at 1.0 × 10−11 M, presenting an increase of resistance of 13.5% in relation to its bare condition. [ABSTRACT FROM AUTHOR]

Serotherapy is the only approved method to treat victims of snakebites; therefore, it is very important to identify the type of venom implicated in the accident to ensure the most specific antivenom is administered to the patient. In Brazil, the majority of snakebite accidents are from snakes of Bothrops genus. In this work, we developed an immunosensor capable to recognize specifically venoms from Bothrops snakes based on the electrochemical impedance spectroscopy technique. For this, Crofer 22 APU steel was used as transducer substrate functionalized with antibothropic antibodies. The immunosensor was incubated with different concentrations of venoms from Bothrops, Crotalus, and Micrurus in order to evaluate its specificity. The formation of the antigen-antibody immunocomplex at the surface of the transducer substrate increased the leakage resistance in a concentration-dependent manner when the device was exposed to the bothropic venom, while no considerable variation of this parameter could be observed for the venoms of the heterologous genera. In addition to the observed specificity, the sensor proved reusable, since the immersion in an elution buffer permitted many regeneration and charge cycles without considerable loss of activity. The results strongly indicated that the developed immunosensor stands as a promising device to aid in snakebites diagnosis. [ABSTRACT FROM AUTHOR]

Researchers use several different analytical techniques, such as ORAC, ABTS, or FRAP, for measuring the antioxidant capacity of bioactive compounds. However, many authors do not take into account that these three techniques have different objectives. This contribution reports on the use of two types of tests to evaluate the antioxidant activity of four stilbene tests based first on the hydrogen atom transfer reaction (ORAC method) and the second on the single electron transfer reaction (ABTS and FRAP assays). For the ORAC assay, the greatest antioxidant activity was shown by resveratrol, followed by oxyresveratrol, pterostilbene, and pinosylvin, while in the ABTS assay, the highest antioxidant capacity was presented by oxyresveratrol, followed by resveratrol, pinosylvin, and finally pterostilbene. In the FRAP assay, the reducing activity shown by all the stilbenes was below that obtained for trolox. The role of phenolic hydroxyl groups was studied. The technique used should be selected taking into account the objectives and the conditions of the medium. [ABSTRACT FROM AUTHOR]

Background: Leukaemia represents 30-40% of all paediatric malignant tumours and is the main cause of death in patients aged <15 years. One of the main complications in these patients is infection, which may often occur in the oral cavity. Chemotherapy-related oral health problems may be reduced by oral healthcare strategies based on the International Caries Detection and Assessment System (ICDAS) and Caries Management by Risk Assessment (CABRA). Case report: A case is reported of a 14-year-old girl treated for leukaemia who presented with established dental caries lesions which were classified and treated according to ICDAS and CABRA protocols. After three, no new caries was observed. Follow-up and conclusion: ICDAS and CAMBRA provide useful and effective guidance for the avoidance of dental and systemic problems. Their introduction into standard practice could reduce the legal difficulties derived from dental treatment in these patients. [ABSTRACT FROM AUTHOR]

The present work reports the synthesis of four electron-acceptor beta-substituted thiophenes that were studied as monomers for electrochemical polymerization with 3,4-ethylenedioxythiophene (EDOT), an electron-donating monomer, aiming the combination of electron-acceptor and donor monomer thiophene to a simpler and convenient build up of novel donor-acceptor copolymeric materials via electrochemical polymerization. Four novel copolymers poly(EDOT-co-3-thiophene phenylacetate), (PEDOT-co-PPhTAc-2a), poly(EDOT-co-3-thiophene(4-nitrophenyl)acetate) (PEDOT-co-PPhTAc-2b), poly(EDOT-co-3-thiophenephenylcarboxylate) (PEDOT-co-PPhTCb), and poly(EDOT-co-3-(phenoxymethyl)thiophene) (PEDOT-co-PPhOMT) were electrochemically polymerized. The monomers were characterized by spectrometric techniques (FTIR, H NMR, and C NMR), and the copolymers were identified by electrochemical analyses and FT-IR. Although the corresponding homopolymers could not be obtained, in the presence of EDOT, the copolymers were formed in a quasi-reversible electrochemical kinetics. The infrared spectra of the copolymers as well the electrochemical profile corroborates their obtaining. The mass variation during the electrosynthesis was analyzed using a quartz crystal microbalance. The film's morphologies were investigated by SEM. Interestingly, the combination of electron-rich monomer thiophene (EDOT) and these electron-deficient carboxy-substituted thiophenes might be a convenient building block couple to increase the performance control of physic-chemical properties of mixed polythiophenes with innovative applications and they also showed a possible applicability as charge storage device. [ABSTRACT FROM AUTHOR]

In this work, anode-supported solid oxide fuel cells (SOFC) were tested with a yttria-stabilized zirconia (YSZ) (8 mol% YO-ZrO)/gadolinium-doped ceria (GDC) (CeGd O) bilayer electrolyte and two lanthanum strontium cobalt ferrite (LSCF) composition as functional cathode layer: LaSrCoFeO (LSCF 1) and LaSrCoFeO (LSCF 2). The functional cathode layers were made of 50 % ( w/ w) LSCF and 50 % ( w/ w) GDC. Microstructural characterization was performed by scanning electron microscopy and X-ray diffraction. Electrochemical impedance spectroscopy (EIS) and power measurements were performed under oxygen and hydrogen atmospheres. The microscopy studies showed that the LSCF 2 functional layer is more uniform and adherent to the electrolyte and the cathode collector than the LSCF 1 functional layer, which has cracks, chips, and lower adhesion. The use of the LSCF 2 layer allowed an approximately 25-fold reduction in ohmic resistance (0.06 Ω cm) compared with the LSCF 1 layer (1.5 Ω cm). The power measurements showed a considerable increase in the power cell using LSCF 2 (approximately 420 mW cm) compared with the power cell using LSCF 1 (approximately 180 mW cm). [ABSTRACT FROM AUTHOR]

This article aims to present a new alternative to waste management of spent Li-ion batteries from cell phones. In this sense, the proposed is recycling the cobalt from Li-ion cathode by electrodeposition and apply it as corrosion protector of AISI 430 stainless steel. Thus, two greatest environmental problems can be solved, producing a low-cost and high-corrosion-resistant stainless steel. The cobalt electrodeposition bath came from acid dissolution of spent Li-ion cathode with chemical formula LiCoO. The charge efficiency for cobalt electrodeposition in −1.0 V and pH = 3 reaches 95 %. A protective layer of CoO was successfully obtained by treatment of AISI 430 stainless steel with cobalt electrodeposited at 800 °C for 200 h in air atmosphere. The corrosion current of AISI 430 stainless steel in artificial seawater was reduced from 30 to 0.76 μA cm. The treatment proposed produces a AISI 430 stainless steel with double of corrosion resistance and half of cost if compared with AISI 304 stainless steel. [ABSTRACT FROM AUTHOR]

The anticorrosion performance of commercial extract of ethanolic propolis (EP)-coated mild steel samples immersed in a 3.5% w/v NaCl in neutral and near neutral media was evaluated by classical electrochemical and electrochemical probe beam deflection techniques. The functional groups and major components of the extract were identified by Fourier transform infrared spectroscopy and high-performance liquid chromatography, respectively. The extract and the major constituent identified in the extract, 3,5-diprenyl-4-hydroxycinnamic acid (DHCA), are poorly hydro-soluble in a neutral medium. The bare and coated carbon steel surfaces were characterized by scanning electron microscopy and atomic force microscopy before and after a saline immersion. The electrochemical response of the coated electrodes was compared with bare mild steel electrodes and all qualitative and quantitative data obtained supported the hypothesis that EP is a potential mild steel corrosion inhibitor. Although several flavonoids are known to have remarkable antioxidant properties and be effective metal corrosion inhibitors, this work is pioneering in its evaluation of the inhibitory capacity of a natural product whose main constituent is DHCA. [ABSTRACT FROM AUTHOR]

This paper describes briefly the use of Ni-YSZ (yttrium oxide doped with 8 % in mol of zirconium oxide) for methanol oxidation in 1.0 mol L KOH solution. The Ni-YSZ has a great performance for methanol oxidation reaching a current density around 160 mA cm. This value is at least four times greater than in platinum electrode. The high performance of Ni-YSZ compared with Pt electrode can also be viewed in measures electrochemical impedance spectroscopy. The Ni-YSZ shows the charge transfer resistance around 1.80 Ohm cm. Thus, in our material, the effect of NiO(OH) barrier is drastically reduced. The chronoamperograms for methanol oxidation at potential equal to 1.0 V shows that the charge density for Ni-YSZ electrode is about four times larger than in Pt electrode. [ABSTRACT FROM AUTHOR]

The supercapacitive behavior of the metallic cobalt recycled from Li-ion batteries has been studied in this work. The reversibility of both redox process (Co/Co) and (Co/Co) in KOH 6 mol L is very high and promising for capacitive applications in electrochemical devices. The specific capacitances calculated from cyclic voltammetry and electrochemical impedance spectroscopy show a good agreement, giving the value of 625 Fg. The electrode morphology presents a high porosity, thus an electrical equivalent circuit composed of two parallel resistance and capacitance elements in series was proposed. The specific capacitance values calculated from charge/discharge curves at 0.23 and 2.3 mA/cm are 601 and 384 Fg, respectively. Thereby, it was observed that metallic cobalt recycled from ion-Li batteries is compatible with other supercapacitive materials. This shows that cobalt recycling from Li-ion batteries is economically and environmentally viable for application in supercapacitor devices. [ABSTRACT FROM AUTHOR]

In this work the metallic cobalt was electrodeposited on 430 steel in order to obtain a low electrical resistance film made to CoO. Pure cobalt was obtained by acidic dissolution of lithium cobalt oxide (LiCoO) present in exhausted Li-ion battery cathode. The electrodeposition was performed with a 96% efficiency at a potential of 1.50 V versus Ag/AgCl. The electrodeposited cobalt showed the face-centered cubic (23%) and hexagonal centered (77%) phases. After oxidation at 850 °C for 1000 h in air, the cobalt layer was transformed into the CoO phase. On the other hand, a sample without cobalt showed the usual CrO and FeCrO phases. After 1000 h at 850 °C, in air the area specific resistance of the sample with the cobalt oxide layer was 0.038 Ω cm, while it was 1.30 Ω cm for the bare sample. [ABSTRACT FROM AUTHOR]

The effect of cathodic activation of sprayed La0.8Sr0.2MnO3 (LSM) films has been studied by electrochemical spectroscopy impedance (EIS). LSM powder was prepared by a citrate route and X-ray diffraction analyses show a complete LSM crystallization without La2O3 or La(OH)3 as side products. Porosity and grain size estimated from scanning electronic microscopy gave values of 33% and 100 nm, respectively. EIS measurement was performed on a Pt/yttria-stabilized zirconia/LSM cell before and after a cathodic current load (300 mA/cm2) on LSM electrode. The relaxation process, which is time-dependent, has been investigated. A drastic decrease of the electrode resistance was noticed just after applying the cathodic current, but after 9 h at optimized valence configuration in air at 850 °C, the recorded polarization resistance gradually enhanced until it almost reached the initial value. The resulting diagrams have been fitted using a Gerischer associated with a resistor and constant phase elements. This simple method has permitted us to observe that only the electrode interfaces are modified by a cathodic activation and the microstructure remains nearly constant. [ABSTRACT FROM AUTHOR]

In the steel industry, nickel coating on copper has increased the lifespan of continuous ingot casting molds. The objective of this work is to estimate the porosity of nanocrystalline nickel electrodeposited onto copper. Characteristics of nickel coating such as hardness, wear resistance, porosity, morphology, and adhesion are very important for maximum performance of molds. The effective porosity in nickel coating was determined by using anodic voltammetry. The porosity of electrodeposited nickel onto copper increased from 0.16% up to 6.22% as the current density increased from 1.5 up to 8.0 A dm-2. The morphology of the nickel electrodeposited at lower current densities was more compact. Tribological properties were studied using hardness measurements, and calotest. Results of calotest indicated a wear coefficient of 10-6 for all samples. An extremely low friction coefficient of 0.06-0.08 was obtained for the sample deposited with a current density of 1.5 A dm-2, and a friction coefficient of 0.15-0.21 was measured for the nickel coating electrodeposited at a current density of 5 A dm-2. Effects of the current density of the electrodeposition process on the morphology, porosity, and tribological properties were evaluated. [ABSTRACT FROM AUTHOR]

The original version of this paper was unfortunately published with some errors which are corrected by publishing this Correction article. [ABSTRACT FROM AUTHOR]

Based on the necessity of better understanding the trade-off between the accuracy and computational efficiency of fuel cell models, this work aims to evaluate the impact of a simplifying assumption that permits the analytical description of water transport in the electrolyte. This simplification is the usage of a mean value for the water diffusivity, which is a function of the membrane’s water content. For this test, analytical expressions for the transport are developed for two different electro-osmotic drag models, Springer’s linear description and a piecewise-linear proposal. Those expressions are implemented on a PEMFC model along with the non-simplified description, which is solved numerically. Both submodels have good accuracies on the polarization curve while the water concentration does not reach the region of the peak in diffusivity (λ≅4\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\lambda \cong 4$$\end{document}), indicating that the underestimation of the back-diffusion caused by the mean can hinder the accuracy. As for computational time, improvements of 49.85 and 23.69% are, respectively, obtained for Springer’s and the piecewise-linear electro-osmotic drag models for a larger interval between the solved current densities. However, the analytical expressions cause a performance loss of 6.80% when a smaller interval is used for the piecewise description. Therefore, the assumption of a mean diffusivity can be beneficial for models if the cell operates under well-humidified conditions and with fewer points in the domain, but it loses some of its benefits with smaller intervals in current density. [ABSTRACT FROM AUTHOR]