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Background: Efficient monitoring of glucose concentration in the human body necessitates the utilization of electrochemically active sensing materials in nonenzymatic glucose sensors. However, prevailing limitations such as intricate fabrication processes, lower sensitivity, and instability impede their practical application. Herein, ternary Cu-Co-Ni-S sulfides nanoporous network structure was synthesized on carbon fiber paper (CP) by an ultrafast, facile, and controllable technique through on-step cyclic voltammetry, serving as a superior self-supporting catalytic electrode for the high-performance glucose sensor. Results: The direct growth of free-standing Cu-Co-Ni-S on the interconnected three-dimensional (3D) network of CP boosted the active site of the composites, improved ion diffusion kinetics, and significantly promoted the electron transfer rate. The multiple oxidation states and synergistic effects among Co, Ni, Cu, and S further promoted glucose electrooxidation. The well-architected Cu-Co-Ni-S/CP presented exceptional electrocatalytic properties for glucose with satisfied linearity of a broad range from 0.3 to 16,000 μM and high sensitivity of 6829 μA mM− 1 cm− 2. Furthermore, the novel sensor demonstrated excellent selectivity and storage stability, which could successfully evaluate the glucose levels in human serum. Notably, the novel Cu-Co-Ni-S/CP showed favorable biocompatibility, proving its potential for in vivo glucose monitoring. Conclusion: The proposed 3D hierarchical morphology self-supported electrode sensor, which demonstrates appealing analysis behavior for glucose electrooxidation, holds great promise for the next generation of high-performance glucose sensors. [ABSTRACT FROM AUTHOR]

The technique of using biochar-based catalysts in persulfate activation is a promising alternative to remov emerging and refractory pollutants (e.g., tetracycline-) in wastewater. However, the situation of biochars derived from waste pulp/paper mill sludge is still unclear. The pulp/paper mill sludge biochars (SBC300, SBC500, and SBC700) were obtained and characterized at pyrolysis temperatures of 300, 500, and 700 °C. Tetracycline degradation using peroxydisulfate activated by SBCs was investigated. The results demonstrated the removal efficiencies of tetracycline in SBC300-, SBC500- and SBC700-peroxydisulfate systems, which increased with the pyrolysis temperatures and were 4.3, 4.8, and 5.0 times that of a system with peroxydisulfate alone. The experiments of free radical quenching, singlet oxygen quenching, and electrochemistry indicated that the degradation of tetracycline in SBC-peroxydisulfate systems was mainly not a free radical pathway, but a non-radical pathway. Singlet oxygen (1O2) and electron transfer could play main roles in the degradation removal of tetracycline. The removal efficiencies of tetracycline in the SBC-peroxydisulfate systems could be up to 96.0% (SBC700-peroxydisulfate) under the optimum dosage of SBC, the molar ratio of peroxydisulfate to tetracycline and the solution pH value. The results indicate that a SBC700-peroxydisulfate system could be an effective "trash-to-treasure" treatment technique for wastewater containing antibiotics. [ABSTRACT FROM AUTHOR]

[Display omitted] • Paper mill sludge-based biochar (PSBC) is synthesized for PDS activation. • High BPA removal efficiency can be achieved by the PSBC950/PDS process. • Both radical and non-radical pathways are involved in BPA degradation. • Fe(Ⅱ), O V , C O, and graphitized sp2-C with defects were identified as active sites. • The enhancement effects of C O and defects to the electron transfer were confirmed. Paper mill sludge generated from the pulp and papermaking industries has inherent iron and carbon contents. Herein, the biochar derived from paper mill sludge (PSBC) was synthesized via simple pyrolysis processes and applied as an efficient persulfate (PDS) activator for the removal of Bisphenol A (BPA) in water. The unique properties of PSBC endowed it with multiple active sites including Fe(II) species, oxygen vacancy, C O, and graphite sp2-C with defects, owing to which, the PSBC/PDS process presented satisfactory performance with BPA removal efficiency up to 98 % within 60 min. Both of the radical and non-radical pathways were revealed to be involved in the BPA degradation. Based on the results of theoretical calculation, the existences of some special structures in PSBC effectively facilitated the electron transfer process of PDS activation. The process also exhibited a high anti-interference capability to coexisting substances and the universality toward various organic contaminants degradation. And the used PSBC can be recovered by simple thermal treatment. This work provided a promising heterogeneous PDS activator with plentiful active sites and satisfactory efficiency, which can be beneficial to the cost reduction of wastewater treatment and promotes the application of paper mill sludge in the area of environmental remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] • A highly active 2e-WOR electrocatalyst was prepared by modifying CFP with SAMs. • SAMs modified CFP achieves a high H 2 O 2 yield of 79.8 μmol min−1 cm−2 at 2.1 V. • SAMs modification enriches the 2e-WOR active site and reduces the OER active site by modulating the ΔG*OH. • Carbon atoms adjacent to O=C-M are active sites for efficient 2e-WOR. • O=C-M are rooted from the reaction between the functional group on CFP and SAMs. Two-electron water oxidation (2e-WOR) is an attractive method for the electrosynthesis of hydrogen peroxide (H 2 O 2). However, its practical application is limited by the viable 2e-WOR catalysts that can ensure high selectivity and high H 2 O 2 yield. In this paper, a highly active 2e-WOR electrocatalyst was prepared by modifying carbon fiber paper (CFP) with a self-assembled membrane (SAMs). The SAMs modified CFP can achieve an H 2 O 2 yield of 79.8 μmol min−1 cm−2 and an H 2 O 2 selectivity of 82.5% at a low potential (2.1 V vs. RHE). The DFT calculation reveals that SAMs modification can modulate the *OH binding energy of the active site on CFP, thus leading to a significantly improved selectivity and production rate of H 2 O 2. Moreover, the 2e-WOR performance is found to be independent of the functional tail groups of SAMs because the electron transfer during the 2e-WOR occurs through direct electron transfer via the carbon atoms adjacent to the O=C-M on carbon fiber rather than the well-known electron tunneling through SAMs. This study provides a new strategy for surface modification of 2e-WOR carbon-based catalysts and opens a new way for efficient electrosynthesis of H 2 O 2. [ABSTRACT FROM AUTHOR]

In this study, the performance of a paper-based, screen-printed biofuel cell with mesoporous MgO-templated carbon (MgOC) electrodes was improved in two steps. First, a small amount of carboxymethyl cellulose (CMC) was added to the MgOC ink. Next, the cathode was modified with bilirubin prior to immobilizing the bilirubin oxidase (BOD). The CMC increased the accessibility of the mesopores of the MgOC, and subsequently, the performance of both the bioanode and biocathode. CMC also likely increased the stability of the electrodes. The pre-modification with bilirubin improved the orientation of the BOD, which facilitated direct electron transfer. With these two steps, an open circuit potential of 0.65 V, a maximal current density of 1.94 mA cm−2, and a maximal power density of 465 μW cm−2 was achieved with lactate oxidase as bioanode enzyme and lactate as fuel. This is one of the highest reported performances for a biofuel cell. [ABSTRACT FROM AUTHOR]

The detection of hydrogen peroxide and the control of its concentration are important tasks in the biological and chemical sciences. In this paper, we developed a simple and quantitative method for the non-enzymatic detection of H2O2 based on the selective etching of Au@Ag nanorods with embedded Raman active molecules. The transfer of electrons between silver atoms and hydrogen peroxide enhances the oxidation reaction, and the Ag shell around the Au nanorod gradually dissolves. This leads to a change in the color of the nanoparticle colloid, a shift in LSPR, and a decrease in the SERS response from molecules embedded between the Au core and Ag shell. In our study, we compared the sensitivity of these readouts for nanoparticles with different Ag shell morphology. We found that triangle core–shell nanoparticles exhibited the highest sensitivity, with a detection limit of 10−4 M, and the SERS detection range of 1 × 10−4 to 2 × 10−2 M. In addition, a colorimetric strategy was applied to fabricate a simple indicator paper sensor for fast detection of hydrogen peroxide in liquids. In this case, the concentration of hydrogen peroxide was qualitatively determined by the change in the color of the nanoparticles deposited on the nitrocellulose membrane. [ABSTRACT FROM AUTHOR]

Prussian blue analogues (PBAs) are promising materials due to their rich active sites and straightforward synthesis. However, their limited conductivity and electron transfer inefficiency hinder practical applications. This study utilizes a simple one-pot synthesis approach to produce a tungsten-disulfide (WS 2) and iron-cobalt Prussian blue analogue composite (WS 2 -PBA), enhancing conductivity and electron transfer rate performance. Through the inclusion of sodium citrate into the solution, the S-edge site concentration of WS 2 increases. This augmentation introduces additional active sites and defects into the catalyst, enhancing its catalytic activity. The effectiveness of the WS 2 -PBA 3D-Origami paper device for lactate detection in sweat is also evaluated for biomedical applications. The device demonstrated a robust relationship between the lactate concentration and current intensity (R2 = 0.997), with a detection limit of 1.83 mM. Additionally, this platform has successfully detected lactate in clinical sweat, correlating with the high-performance liquid chromatography test results, suggesting promising prospects for clinical diagnosis. In the future, the excellent catalytic and R ct performance of the WS 2 -PBA will enable its use in biomedical applications. [ABSTRACT FROM AUTHOR]

A disposable paper-based glucose biosensor with direct electron transfer (DET) of glucose oxidase (GOX) was developed through simple covalent immobilization of GOX on a carbon electrode surface using zero-length cross-linkers. This glucose biosensor exhibited a high electron transfer rate (ks, 3.363 s−1) as well as good affinity (km, 0.03 mM) for GOX while keeping innate enzymatic activities. Furthermore, the DET-based glucose detection was accomplished by employing both square wave voltammetry and chronoamperometric techniques, and it achieved a glucose detection range from 5.4 mg/dL to 900 mg/dL, which is wider than most commercially available glucometers. This low-cost DET glucose biosensor showed remarkable selectivity, and the use of the negative operating potential avoided interference from other common electroactive compounds. It has great potential to monitor different stages of diabetes from hypoglycemic to hyperglycemic states, especially for self-monitoring of blood glucose. [ABSTRACT FROM AUTHOR]

Porous carbon encapsulated non-precious metal nanocatalysts have recently opened the ways towards the development of high-performance water remediation and energy conversion technologies. Herein, we report a facile, scalable and green synthetic methodology to fabricate porous carbon encapsulated transition metal nanocatalysts (M@TP: M = Cu, Ni, Fe and Co) using commercial tissue paper. The morphology, crystalline structure, chemical composition and textural properties of the M@TP nanocatalysts were thoroughly characterized. The catalytic activity of the M@TP nanocatalysts was investigated for the degradation of Congo red (CR) via peroxymonosulfate activation. Co@TP-6 was found to be the most active catalyst allowing 97.68% degradation in 30 min with a higher rate constant of 0.109 min−1. The nanocatalysts also displayed a carbon shell thickness-dependent electrocatalytic hydrogen evolution reaction (HER) activity, most likely due to the shielding effect of the carbon layers over the electron transfer (ET) processes at the metal core/carbon interfaces. Remarkably, the Ni@TP-6 electrocatalyst, with the smaller carbon shell thickness, showed the best electrocatalytic performance. They delivered an ultralow onset potential of −30 mV vs RHE, an overpotential of 105 mV at a current density of 10 mA·cm−2 and an excellent electrochemical stability to keep the 92% of the initial current applied after 25000 s, which is comparable with the HER activity of the state-of-the-art Ni-based catalysts. [ABSTRACT FROM AUTHOR]

Screen printed carbon electrodes (SPCEs) are widely used in the field of electrochemical sensors, especially in the areas of food, water, environmental quality, and healthcare applications. In this context, microband SPCEs were fabricated on Whatman paper, overhead projection (OHP) sheet and cotton textile substrates for the development of cost-effective electrochemical biosensors. The fabricated electrodes were subjected to three consecutive processes such as thermal, electrochemical and oxygen plasma treatment. Surface morphologies of SPCEs after each treatment stage were observed using scanning electron microscope for process standardization. Electrochemical performances of the fabricated SPCEs were analyzed using cyclic voltammetry. SPCEs on OHP substrate exhibited a single electron transfer rate at ΔEp of 57 mV and ipa/ipc = 1 (n = 3) with significant repeatability and reproducibility compared to SPCEs on paper and textile substrates. The role of activation of edge plane pyrolytic graphite of SPCEs in achieving the reversible reaction with single electron transfer characteristics has been analysed and reported. The effectiveness of the activated SPCEs on the OHP substrate was tested by detecting 1 mM of uric acid and ascorbic acid with KCl as an electrolyte. [ABSTRACT FROM AUTHOR]

Simultaneous detection of multiple tumor biomarkers in body fluids could facilitate early diagnosis of lung cancer, so as to provide scientific reference for clinical treatment. This paper depicted a multi-parameter paper-based electrochemical aptasensor for simultaneous detection of carcinoembryonic antigen (CEA) and neuron-specific enolase (NSE) in a clinical sample with high sensitivity and specificity. The paper-based device was fabricated through wax printing and screen-printing, which enabled functions of sample filtration and sample auto injection. Amino functional graphene (NG)-Thionin (THI)- gold nanoparticles (AuNPs) and Prussian blue (PB)- poly (3,4- ethylenedioxythiophene) (PEDOT)- AuNPs nanocomposites were synthesized respectively. They were used to modify the working electrodes not only for promoting the electron transfer rate, but also for immobilization of the CEA and NSE aptamers. A label-free electrochemical method was adopted, enabling a rapid simple point-of-care testing. Experimental results showed that the proposed multi-parameter aptasensor exhibited good linearity in ranges of 0.01–500 ng mL−1 for CEA (R2 = 0.989) and 0.05–500 ng mL−1 for NSE (R2 = 0.944), respectively. The limit of detection (LOD) was 2 pg mL−1 for CEA and 10 pg mL−1 for NSE. In addition, the device was evaluated using clinical serum samples and received a good correlation with large electrochemical luminescence (ECL) equipment, which would offer a new platform for early cancer diagnostics, especially in those resource-limit areas. • The aptasensor could enable simultaneous detection of two tumor markers in a single sample with high sensitivity. • The aptasensor had a fast response time as a label-free electrochemical detection method was adopted. • The aptasensor was fabricated by wax printing and screen-printing, which could be mass-produced easily with low cost. [ABSTRACT FROM AUTHOR]

In this work, we present a multiplexed (eight simultaneous measurements) paper-based electrochemical device developed in a very simple way and using low-cost materials, such as paper, carbon ink and multifunctional connector headers. Meanwhile, we have also combined the paper-based electrochemical platform with a glass-fiber strip in order to integrate easily a sampling step. Both approaches, simultaneous measuring and sampling, have been applied to the determination of glucose using bienzymatic biosensors. They are fabricated by adsorbing the mixture of enzymes (glucose oxidase and horseradish peroxidase), as well as the ferrocyanide, mediator of the electron transfer, on the paper-based electrode. After drying, the measuring solution (containing either glucose standards or samples) is added and the eight corresponding chronoamperograms are recorded. In the case of the microfluidic approach for sampling purposes, the glass-fiber pad (sampler) is immersed in a container with the solution, which flows by capillarity until it reaches the working electrode. The integration of one more step of the analytical process advances towards real and useful lab-on-a-chip devices. With these designs, a linear range comprised between 0.5 and 15 mM was achieved for glucose determination, with an excellent precision. If the sampler is employed, it is not necessary to use micropipettes and, nevertheless, precise measurements are obtained. The RSD of the slopes obtained for different calibrations performed in different days, with different arrays of electrochemical cells and different solutions is ca. 1%. Accurate results are obtained in the determination of glucose in real samples (orange fruit and cola beverages). Image 1 • Precise sampling is integrated in a paper-based electroanalytical device for glucose biosensing. • Adding a sampler to a paper-based enzymatic sensor advances towards lab-on-paper platforms. • A paper-based simple electrochemical device for eight simultaneous measurements is presented. • A low-cost paper-based sensor samples which analyzes food samples with 8 simultaneous measurements is developed. • Accurate results are obtained for glucose determination in orange fruits and cola beverages. [ABSTRACT FROM AUTHOR]

Inspired by the design of folding greeting cards and tissue drawing covers, a photoelectrochemical (PEC) lab-on-paper device with a controllable fluid separator, producing both reaction zone and detection zone, was explored for ultrasensitive detection of adenosine 5′-triphosphate (ATP) via mimic peroxidase-transfer enhancement of photocurrent response. To realize it, the DNA1, aptamer, and DNA2 as well as the mimic peroxidase of G-quadruplex/hemin modified Au nanocubes were linked on the graphene oxide-functionalized reaction zone via the DNA hybridization. Meanwhile, three-dimensional CuO nanoflowers (CuO NFs) as a photoactive material with outstanding electron transfer ability and absorption of light were grown in situ on the detection zone, providing a PEC active interface. Besides, an innovative fluid separator was elaborately designed by assembling a strip of paper with a hydrophilic channel, providing an effective way to bridge the gap between the two zones with a controllable drawing way, which could successfully avoid the signal interference caused by modifying biomolecules layer by layer on photosensitive materials. In the presence of ATP, the G-quadruplex/hemin modified in the reaction zone was dissociated due to the specific recognition of ATP with aptamer and released into the detection zone with the assistance of controllable fluid separator. The free G-quadruplex/hemin could catalyze hydrogen peroxide to generate oxygen for the consumption of photo-induced electrons from CuO NFs, which could further promote the electron-hole carriers separation efficiency, and eventually resulting in the enhancement of PEC signal. The proposed PEC lab-on-paper device could be employed for specific detection of ATP in the range from 5.0 to 3.0 × 103 nM with a detection limit of 2.1 nM. • The CuO nanoflowers were grown in situ on rGO-modified detection zone. • The lab-on-paper microfluidic systems simplify the analytical processes. • The modification of biomolecules was separated from the PEC transducer. • The fluid separator was designed as a bridge between two functional zones. • The device was applied to detect ATP with high sensitivity, stability and selectivity. [ABSTRACT FROM AUTHOR]

Nanowires synthesized from metal oxides exhibit better conductivity than nanoparticles due to their greater aspect ratio which means that they can transmit electrons over longer distances; in addition, they are also more widely available than pili because their synthesis is not affected by the bacteria themselves. However, there is still little research on the application of metal oxides nanowires to enhance power generation of microbial fuel cells (MFC). In this study, a simple hydrothermal synthesis method was adopted to synthesize α-FeOOH nanowires on carbon paper (α-FeOOH-NWs), which serve as an anode to explore the mechanism of power generation enhancement of MFC. Characterization results reveal α-FeOOH-NWs on carbon paper are approximately 30–50 nm in diameter, with goethite structure. Electrochemical test results indicate that α-FeOOH nanowires could enhance the electrochemical activity of carbon paper and reduce the electron transfer resistance (R ct). Furthermore, α-FeOOH-NWs made the power density of MFC 3.2 times of the control device. SEM result demonstrates that nanowires are beneficial to the formation of biofilms and increase biomass on the electrode surface. Our results demonstrate that nanowires not only improve the electrochemical activity and conductivity of carbon paper but also facilitate the formation of biofilms and increase the biomass of the anode surface. These two mechanisms work together to boost extracellular electron transfer and power generation efficiency of MFC with α-FeOOH-NWs. Our study provides further evidence for the electrical conductivity of metal nanowires, promoting their potential applications in electricity generation such as MFC or other energy development fields. • α-FeOOH nanowires enhanced electron transfer rate and reduced Rct. • α-FeOOH nanowires are beneficial to the formation of biofilms. • α-FeOOH nanowires made the power density of MFC 3.2 times than the control. [ABSTRACT FROM AUTHOR]

Molybdenum oxides are widely used as electrocatalysts due to their polymetallic oxidation state, abundant reactive sites and low production cost. However, the low electrical conductivity and easy agglomeration has limited their practical application. Here, MoO 3 nanowires encapsulated with ZIF-67 polyhedra were grown in situ on expanded graphite paper (EGP) by a simple hydrothermal synthesis method, and then the precursors were pyrolyzed to obtain self-supported Co-MoO x @N-doped carbon/EGP composites. Thanks to the three-dimensional porous structure and the synergistic effect of Co and multi-valance MoO x , the as-prepared Co-MoO x @N-doped carbon/EGP exhibits the excellent performances of OER (η 10 = 256 mV) and HER (η 10 = 138 mV), and a small Tafel slope and good durability. Furthermore, the assembled water splitting device achieved a current density of 10 mA cm−2 at a low voltage of 1.62 V and the excellent stability after 24 h continuous water splitting. [Display omitted] • Self-standing Co-MoO x @NC/EGP exhibits the excellent OER performance with the overpotential of 256 mV at 10 mA cm−2. • Three-dimensional structure and heterogeneous interface can expose more active sites and promote the transfer of electrons. • The assembled water splitting device only require a voltage of 1.62 V to achieve a current density of 10 mA cm−2. [ABSTRACT FROM AUTHOR]

In this work, we present the development of an immunosensor for the direct, selective, and sensitive determination of symmetric dimethylarginine (SDMA) in urine, in view of the emerging role of this molecule as a biomarker for renal disease. SDMA is almost completely excreted by the kidneys, hence in renal dysfunction, the excretion is decreased, resulting in accumulation in plasma. Reference values for plasma or serum have already been established in small animal practice. Values < 15 μg/dL are considered normal, 15–19 μg/dL are values of concern, and at values > 20 μg/dL kidney disease is likely. The proposed electrochemical paper-based sensing platform uses anti-SDMA antibodies for targeted detection of SDMA. Quantification is related to a decrease in the signal of a redox indicator due to the formation of an immunocomplex that interferes with electron transfer. Square wave voltammetry measurements showed a linear correlation of the peak decline for 50 nM - 1 μM SDMA with a detection limit of 15 nM. The influence of common physiological interferences caused no significant peak reduction, indicating excellent selectivity. The proposed immunosensor was successfully applied for the quantification of SDMA in human urine of healthy individuals. Surveillance of SDMA concentration in urine could prove to be very valuable in the diagnosis or monitoring of renal disease. [ABSTRACT FROM AUTHOR]

We report here the rational development of MnO 2 nanorods coated tea bag filter paper (TBFP) as a self-standing, bendable, and disposable electrochemical probe for the sensitive and selective H 2 O 2 detection and addresses their challenges in H 2 O 2 sensing via the replacement of 'O' with 'S' in the form of MnS microcubes and its core@shell architecture with MoS 2. The as-configured MnS@MoS 2 /TBFP overwhelms the constrains of conventional electrochemical probes including time and cost consumed electrode surface renewability and catalyst loading progression, and the practice of an insulating binder. The hierarchical open porous architectures of MoS 2 -shell favour the diffusion of H 2 O 2 into the core-MnS microcubes, facilitating an analyte utilization efficacy at both the core and shell architectures. The impacts of core@shell morphological features, replacement of 'O' with 'S', surface defects, and lattice distribution of MnS@MoS 2 toward non-enzymatic H 2 O 2 sensing performances are elucidated using variant electrochemical techniques. With the synergism of uniformly implanted and exposed metallic active sites, efficient electron transfer rate, and high analyte utilization efficiency, MnS@MoS 2 /TBFP exposes the low detection limit (120 nM), excellent sensitivity (650 μA mM−1 cm−2), and wide linear range (500 nM-5 mM) on H 2 O 2 detection. Furthermore, the scrutinized non-enzymatic H 2 O 2 detection concerts of MnS/MoS 2 /TBFP are selective, decisive, repeatable, and stable, constructing the excellent recovery rates in human urine sample analyses. Thus, the collective benefits of free-standing, flexible, binder-less, re-functional, and cost-efficient MnS@MoS 2 /TBFP probe actualize the evolution of affordable and high performance H 2 O 2 sensors. Image 1 ∙ MnS@MoS 2 architectures are prepared by using a simple hydrothermal technique ∙MnS@MoS 2 modified TBFP is used as an electrochemical probe for H 2 O 2 sensing ∙Growth and formation mechanisms of MnS@MoS 2 architectures are illustrated ∙Mn(IV)/Mo(IV) centres engaged H 2 O 2 electroreduction mechanism is schematized ∙MnS@MoS 2 /TBFP establishes effectual non-enzymatic H 2 O 2 sensing performances ∙MnS@MoS 2 /TBFP's real sample H 2 O 2 sensing relevancy is actualized in human urine [ABSTRACT FROM AUTHOR]

[Display omitted] • New biocathode including BOD, 4-APA, and BP electrode (BP/4-APA/BOD is suggested. • The biocathode is prepared by electrografting method. • Membraneless paper type EBFCs using this biocathode are fabricated. • This paper type EBFC is well operated even in a condition of living body fluid. • OCV/MPD of this paper type EBFC are 0.612 ± 0.002 V/92.025 ± 0.892 μW cm−2. A new biocathode consisting of bilirubin oxidase (BOD), 4-aminophthalic acid (4-APA) and buckypaper (BP) electrode is suggested for enzymatic biofuel cells (EBFCs). Here, to enhance the electron transfer rate of BOD, electrografting method is imported. When this method and 4-APA are utilized, BP surface has negative charges by the polarity arrangement of 4-APA, forming BP/4-APA structure. With the modification of surface charge, T1 active site within BODs having positive charges are strongly bonded with the negative charges of BP/4-APA in neutral pH condition, while the orientation of T1 site is well aligned by electrostatic interaction. This treatment increases both reactivities of cathodic reaction and EBFC performance. To prove that, the performance of membraneless paper-type EBFCs using the new flexible BP/4-APA/BOD biocathode is investigated. According to the evaluations, their maximum power density and open circuit voltage are 92.025 ± 0.892 μW cm−2 and 0.612 ± 0.002 V with injection of 10 mM glucose which is a condition of living body fluid. Such performances are far better than those of other membraneless EBFCs and are large enough to be utilized as a power source of implantable devices for the human body. [ABSTRACT FROM AUTHOR]

Background: Asymptomatic malaria infections can serve as potential reservoirs for malaria transmission. The density of parasites contained in these infections range from microscopic to submicroscopic densities, making the accurate detection of asymptomatic parasite carriage highly dependent on the sensitivity of the tools used for the diagnosis. This study sought to evaluate the sensitivities of a variety of molecular and serological diagnostic tools at determining the prevalence of asymptomatic Plasmodium falciparum parasite infections in two communities with varying malaria parasite prevalence. Methods: Whole blood was collected from 194 afebrile participants aged between 6 and 70 years old living in a high (Obom) and a low (Asutsuare) malaria transmission setting of Ghana. Thick and thin blood smears, HRP2 based malaria rapid diagnostic test (RDT) and filter paper dried blood spots (DBS) were prepared from each blood sample. Genomic DNA was extracted from the remaining blood and used in Plasmodium specific photo-induced electron transfer polymerase chain reaction (PET-PCR) and Nested PCR, whilst the HRP2 antigen content of the DBS was estimated using a bead immunoassay. A comparison of malaria parasite prevalence as determined by each method was performed. Results: Parasite prevalence in the high transmission site of Obom was estimated at 71.4%, 61.9%, 60%, 37.8% and 19.1% by Nested PCR, the HRP2 bead assay, PET-PCR, HRP2-RDT and microscopy respectively. Parasite prevalence in the low transmission site of Asutsuare was estimated at 50.1%, 11.2%, 5.6%, 0% and 2.2% by Nested PCR, the HRP2 bead assay, PET-PCR, RDT and microscopy, respectively. The diagnostic performance of Nested PCR, PET-PCR and the HRP2 bead assay was similar in Obom but in Asutsuare, Nested PCR had a significantly higher sensitivity than PET-PCR and the HRP2 bead assay, which had similar sensitivity. Conclusions: Nested PCR exhibited the highest sensitivity by identifying the highest prevalence of asymptomatic P. falciparum in both the high and low parasite prevalence settings. However, parasite prevalence estimated by the HRP2 bead assay and PET-PCR had the highest level of inter-rater agreement relative to all the other tools tested and have the advantage of requiring fewer processing steps relative to Nested PCR and producing quantitative results. [ABSTRACT FROM AUTHOR]

Fluorescent test papers are promising for the wide applications in the assays of diagnosis, environments and foods, but unlike classical dye-absorption-based pH test paper, they are usually limited in the qualitative yes/no type of detection by fluorescent brightness, and the colorimetry-based quantification remains a challenging task. Here, we report a single dual-emissive nanofluorophore probe to achieve the consecutive color variations from blue to red for the quantification of blood glucose on its as-prepared test papers. Red quantum dots were embedded into silica nanoparticles as a stable internal standard emission, and blue carbon dots (CDs) were further covalently linked onto the surface of silica, in which the ratiometric fluorescence intensity of blue to red is controlled at 5:1. While the oxidation of glucose induced the formation of Fe 3+ ions, the blue emission of CDs was thus quenched by the electron transfer from CDs to Fe 3+ , displaying a serial of consecutive color variations from blue to red with the dosage of glucose. The high-quality test papers printed by the probe ink exhibited a dosage-sensitive allochromatic capability with the clear differentiations of ~5, 7, 9, 11 mM glucose in human serum (normal: 3–8 mM). The blood glucose determined by the test paper was almost in accordance with that measured by a standard glucometer. The method reported here opens a window to the wide applications of fluorescent test paper in biological assays. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa is the most important opportunistic pathogen leading to serious and life-threatening infections, especially in immunocompromised patients. Because of its remarkable capacity to resist antibiotics, the selection of the right antibiotics with the exact dose for the appropriate duration is critical to effectively treat the infections and prevent antibiotic resistance. Although conventional genotypic and phenotypic antibiotic susceptibility testing (AST) methods have been dramatically advanced, they have suffered from many technical and operational issues as a generalized antibiotic stewardship program. Furthermore, given that most microbial infections are caused by their biofilms, the existing AST methods do not provide evidence-based antibiotic prescribing guidance for biofilm-based infections because the results are based on individual bacteria traditionally grown in their planktonic form. In this work, we create an innovative susceptibility testing technique for P. aeruginosa that offers clinically relevant guidelines and widely adaptable stewardship to effectively treat the infections and minimize antibiotic resistance. Our approach evaluates the antibiotic efficacy by continuously monitoring the accumulated electrical outputs from the bacterial extracellular electron transfer (EET) process in the presence of antibiotics. Our innovative paper-based culturing 3-D scaffold promotes surface-associated growth of bacterial colonies and biofilms. The platform replicates a natural habitat for P. aeruginosa where it can grow similarly to sites it infects. Our technique enables an all-electrical, real-time, easy-to-use, portable AST that can be easily translatable to clinical settings. The entire procedure takes 96 min to provide evidence-based antimicrobial prescribing guidance for biofilm-based infections. [Display omitted] [ABSTRACT FROM AUTHOR]

Supercapacitor is one kind of alternative energy storage devices. Constructing three-dimensional (3D) porous heterogeneous composite electrode materials is an important method to improve the performance of supercapacitor. Herein, we have used a simple solvothermal strategy to prepare NiCo2S4/Ni–Co LDH with a porous heterostructure grown on carbon fiber paper. The composite material is assembled from nanosheets into a 3D structure intertwined with each other. It possesses rich micro-pore size and exhibits excellent electrochemical properties. The unique structure favors for accelerating the electron transfer and electrolyte transport during the electrochemical process. At a current density of 10 mA cm−2, the specific capacitance is 1403 F g−1 (2.67 F cm2). When the current density is increased by 5 times, the specific capacitance is still as high as 1111 F g−1 (2.11 F cm2), showing good rate performance. Under a large current density of 30 mA cm−2, a long-term cycling performance of 5000 cycles has been evaluated. The capacitance retention reaches 111.1%, exhibiting outstanding cycle stability. Furthermore, the assembled symmetric supercapacitor device of also displays good electrochemical activities with an area capacitance of 0.19 F cm−2 at a current density of 3 mA cm−2, and superior cycling ability of high capacitance retention rate (115.4%) after 5000 cycles of charge and discharge process. The above results show that NiCo2S4/Ni–Co LDH is a promising candidate for high-performance supercapacitor. [ABSTRACT FROM AUTHOR]

Abstract: A novel signal amplification strategy for ultrasensitive multiplexed detection of cancer biomarkers using a paper-based microfluidic electrochemical immunodevice is described. Specifically, a controlled radical polymerization reaction is triggered after the capture of target molecules on the immunodevice surface. Growth of long chain polymeric materials provides numerous sites for subsequent horseradish peroxidase (HRP) coupling, which in turn significantly enhances electrochemical signal output. The signal was further amplified through the use of graphene to modify the immunodevice surface to accelerate the electron transfer. Activators generated electron transfer for atom transfer radical polymerization (AGET ATRP) was used in this study for its high efficiency in polymer grafting and better tolerance toward oxygen in air. Glycidyl methacrylate (GMA) was examined to provide excess epoxy groups for HRP coupling. In the electrochemical immunodevice, eight carbon working electrodes, as well as their conductive pads, were screen-printed on a piece of square paper, and the same Ag/AgCl reference and carbon counter electrodes were shared with another piece of square paper via stacking. Using the HRP-O-phenylenediamine-H2O2 electrochemical detection system, four cancer biomarkers: carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), cancer antigen 125 (CA125), and carbohydrate antigen 153 (CA153) were detected. A limit of detection of 0.01, 0.01, 0.05 and 0.05ngmL−1 was demonstrated, respectively. The results show that the proposed strategy offers great promises in providing a sensitive and cost-effective solution for biosensing applications. [Copyright &y& Elsevier]

[Display omitted] • Paper-based Cu 2 O photocathode was collaboratively modified with FeOOH and CuS. • Both the charge carrier separation and electron acceptor reduction were promoted. • Dual-hydrophilic-walls hollow channel was used for promoting homogeneous reaction. • Lab-on-paper homogeneous photocathodic bioassay of microRNA was proposed. Herein, a simple but effective photocathodic signal enhancement strategy was developed based on FeOOH/Cu 2 O/CuS photocathode-enabled simultaneous promotion on charge carrier separation and electron acceptor reduction, and applied to construct lab-on-paper homogeneous cathodic photoelectrochemical (PEC) bioassay via dual-hydrophilic-walls hollow channel (DHWHC) design and target-triggered all-in-one hemin@G-rich DNA release. More concretely, FeOOH as hole extraction layer fleetly extracted photogenerated holes from Cu 2 O, while the photogenerated electrons rapidly transferred to CuS, as electron transfer/consumption accelerator, by photoinduced interfacial charge transfer (IFCT), achieving the efficient charge carrier separation. In the IFCT process, the Cu(II) in CuS was reduced to Cu(I) and it could be oxidized back to Cu(II) by electron acceptor (O 2), forming a Cu(II)/Cu(I) redox circular reaction, which could effectively accelerate the transfer/consumption of photogenerated electrons and further promote electron acceptor reduction. Thus, the simultaneous promotion on charge carrier separation and electron acceptor reduction was fulfilled by FeOOH/Cu 2 O/CuS photocathode, producing a strongly enhanced photocathodic signal. On account of the high mass-transfer rates of DHWHC, the mediation of electron acceptor generation through target-triggered hemin@G-rich DNA release, and the proposed signal enhancement strategy, the ultrasensitive lab-on-paper homogeneous PEC microRNA-141 detection was realized with high selectivity, reproducibility, and stability. This work rendered practical guidelines for developing high-performance lab-on-paper cathodic PEC bioanalysis systems. [ABSTRACT FROM AUTHOR]

• Evaluation of the electrochemical properties of laser-scribed paper-based devices. • The voltammetric behavior can be described as diffusional to the top electrode layer. • The electrode graphene-based material allows a considerably fast electron transfer. Laser-scribed electrochemical paper-based devices (LS-ePADs) are emerging as a greener alternative to conventional carbon electrochemical sensors since their fabrication does not involve the use of chemicals and the resulting devices show good reproducibility, scalability, and interesting electrochemical properties. This work evaluates the electrochemical properties of LS-ePADs using techniques such as cyclic voltammetry and electrochemical impedance spectroscopy (EIS), together with surface characterization by Raman spectroscopy and scanning electron microscopy. The voltammetric behavior of the porous electrode can be described as diffusional to the top electrode layer. Since the porous structure could affect the mass transport, EIS was used to prove that transport resistance is not limiting the charge transfer process in the electrode response. The graphene-based material that forms the electrode surface, identified by Raman spectroscopy, allows a considerably fast electron transfer between the LS-ePADs and the ferri/ferrocyanide molecules. [ABSTRACT FROM AUTHOR]

• The conductive TOCFs network is achieved by an electrostatic self-assembly process. • The paper sensor shows high sensitivity, excellent linearity, and long-time stability. • The paper sensor exhibits superior bending and folding durability. • The sensor shows good responses to human breath, fingertip humidity, and air humidity. Humidity sensors have been widely used for humidity monitoring in industrial fields. However, the application of conventional sensors is limited due to the structural rigidity, high cost, and time-consuming integration process. Owing to the good hydrophilicity, biodegradability, and low cost of cellulose, the sensors built on cellulose bulk materials are considered a feasible method to overcome these drawbacks while providing reasonable performance. Herein, we design a flexible paper-based humidity sensor based on conductive 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose fibers/carbon nanotubes (TOCFs/CNTs) conformal fibers network. The CNTs are dispersed by cationic cetyl trimethyl ammonium bromide (CTAB), which introduces positive charges on the CNTs surface. The conductive fibers are achieved by an electrostatic self-assembly process that positively charged CNTs are adsorbed to the surface of negatively charged TOCFs. The vast number of hydrophilic hydroxyl groups on the surface of TOCFs provide more water molecules adsorption sites and facilitate the electron transfer from water molecules to CNTs, endowing the sensor with an excellent humidity responsive property. Besides, the swelling of the TOCFs greatly damages the conductive CNTs network and further promotes the humidity sensitive performance of the sensor. Benefiting from the unique structure, the obtained sensor exhibits a maximum response value of 87.0% (ΔI/I 0 , and the response limit is 100%), outstanding linearity (R2 = 0.995) between 11 and 95% relative humidity (RH), superior bending (with a curvature of 2.1 cm−1) and folding (up to 50 times) durability, and good long-time stability (more than 3 months). Finally, as a proof of concept, the sensor demonstrates an excellent responsive property to human breath, fingertip humidity, and the change of air humidity, indicating a great potential towards practical applications. [ABSTRACT FROM AUTHOR]

Hybrid nanomaterials fabricated by the heterogeneous integration of 1D (carbon nanotubes) and 2D (graphene oxide) nanomaterials showed synergy in electrical and mechanical properties. Here, we reported the infiltration of carboxylic functionalized single-walled carbon nanotubes (C-SWNT) into free-standing graphene oxide (GO) paper for better electrical and mechanical properties than native GO. The stacking arrangement of GO sheets and its alteration in the presence of C-SWNT were comprehensively explored through scanning electron microscopy, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction. The C-SWNTs bridges between different GO sheets produce a pathway for the flow of electrical charges and provide a tougher hybrid system. The nanoscopic surface potential map reveals a higher work function of the individual functionalised SWNTs than surrounded GO sheets showing efficient charge exchange. We observed the enhanced conductivity up to 50 times and capacitance up to 3.5 times of the hybrid structure than the GO-paper. The laminate of polystyrene composites provided higher elastic modulus and mechanical strength when hybrid paper is used, thus paving the way for the exploitation of hybrid filler formulation in designing polymer composites. [ABSTRACT FROM AUTHOR]

This article was written to serve as an introduction to this issue of the Canadian Journal of Chemistry that honors the contributions to chemistry of Professor D.R. Arnold. It summarizes the observations reported in a communication that appeared in the Journal of the American Chemical Society 30 years ago in June 1973. This historically important communication laid the foundation for his program on the photochemical generation and reactivity of radical ions in solution and also served as a guide for a developing area of interest of many other research groups. [ABSTRACT FROM AUTHOR]

Analysis of cytokines levels in human serum is critical as it can be a "symptom diagnostic biomarker" in COVID-19, giving real-time information about human health status. Here, we present the construction and performance of a low-price immunosensor (∼US$0.428 per test) based on microfluidic paper-based system to detect cytokine for predicting the health status of COVID-19 patients. Interleukin-6 (IL-6) was selected as the detection model for the close relationship between IL-6 and COVID-19. The assay, which we integrated into foldable paper system, leverages the magnetic immunoassay, the streptavidin-horseradish peroxidase (HRP) associated with tetramethyl benzidine/hydrogen peroxide (TMB/H 2 O 2) to amplify the signal for electrochemical readout. To improve the sensitivity of cytokine detection, a hybrid of gold nanoparticles (AuNPs) and polypyrrole (PPy) hydrogel was modified on the working electrode to increase the conductivity and improve the electron transfer rate. With our prototypic origami paper-based immunosensor operated in differential pulse voltammetry (DPV) mode, we achieved excellent results with a dynamic range from 5 to 1000 pg/mL and a lower detection limit (LOD) of 0.654 pg/mL. Furthermore, we evaluated the capability of the clinical application of the proposed immunosensor using human serum samples from a hospital. The results indicate that our proposed immunosensor has great potential in early diagnosing high-risk COVID-19 patients. [ABSTRACT FROM AUTHOR]

The interfacial effect is important for anodes of transition metal dichalcogenides (TMDs) to achieve superior lithium-ion storage performance. In this paper, a MoS2/FeS2 heterojunction is synthesized by a simple hydrothermal reaction to construct the interface effect, and the heterostructure introduces an inherent electric field that accelerates the de-embedding process of lithium ions, improves the electron transfer capability, and effectively mitigates volume expansion. XPS analysis confirms evident chemical interaction between MoS2 and FeS2 via an interfacial covalent bond (Mo–S–Fe). This MoS2/FeS2 anode shows a distinct interfacial effect for efficient interatomic electron migration. The electrochemical performance demonstrated that the discharge capacity can reach up to 1217.8 mA h g−1 at 0.1 A g−1 after 200 cycles, with a capacity retention rate of 72.9%. After 2000 cycles, the capacity retention is about 61.6% at 1.0 A g−1, and the discharge capacity can still reach 638.9 mA h g−1. Electrochemical kinetic analysis indicated an enhanced pseudocapacitance contribution and that the MoS2/FeS2 had sufficient adsorption of lithium ions. This paper therefore argues that this interfacial engineering is an effective solution for designing sulfide-based anodes with good electrochemical properties. [ABSTRACT FROM AUTHOR]

Assessing the performance of active balancing methods poses a significant challenge due to the time required to replicate the equalization of various balancing techniques under identical initial cell conditions. Conventional circuit simulation methods, designed for high-frequency switching behavior, impose a considerable computational burden when applied to the long-term equalization of battery cells. To address this challenge, this paper presents an efficient performance evaluation method employing an average equivalent model of the equalizers. By representing the charge transfer mechanism inherent to the equalization process, the proposed approach is compatible with the most widely used switched-energy-tank equalizers. The validity of this method is confirmed through simulation and experimental results. In the case of four series-connected battery cells, our proposed approach can assess the performance of a three-hour equalization process in just one minute of execution time. The use cases in the paper highlight the practical feasibility of the AM in facilitating performance comparisons of SET-Es under various initial conditions. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs), which are constructed using organic–inorganic combination resources, represent an upcoming technology that offers a competitor to silicon-based solar cells. Electron transport materials (ETMs), which are essential to PSCs, are attracting a lot of interest. In this section, we begin by discussing the development of the PSC framework, which would form the foundation for the requirements of the ETM. Because of their exceptional electronic characteristics and low manufacturing costs, perovskite solar cells (PSCs) have emerged as a promising proposal for future generations of thin-film solar energy. However, PSCs with a compact layer (CL) exhibit subpar long-term reliability and efficacy. The quality of the substrate beneath a layer of perovskite has a major impact on how quickly it grows. Therefore, there has been interest in substrate modification using electron transfer layers to create very stable and efficient PSCs. This paper examines the systemic alteration of electron transport layers (ETLs) based on electron transfer layers that are employed in PSCs. Also covered are the functions of ETLs in the creation of reliable and efficient PSCs. Achieving larger-sized particles, greater crystallization, and a more homogenous morphology within perovskite films, all of which are correlated with a more stable PSC performance, will be guided by this review when they are developed further. To increase PSCs' sustainability and enable them to produce clean energy at levels previously unheard of, the difficulties and potential paths for future research with compact ETLs are also discussed. [ABSTRACT FROM AUTHOR]

Background: Efforts on a global scale for combating malaria have achieved substantial progress over the past twenty years. Two Central American nations have accomplished their goal of eliminating malaria: El Salvador and Belize. Honduras has decreased the incidence of malaria and now reports fewer than 4000 malaria cases annually, aspiring to reach elimination by 2030. To accomplish this goal, it is essential to assess the existing strategies employed for malaria control and to address the task of incorporating novel intervention strategies to identify asymptomatic reservoirs. Methods: A survey for detecting asymptomatic cases was carried out in the community of Kaukira, in Gracias a Dios, Honduras, focusing on malaria transmission during 2023. Asymptomatic community members were recruited as participants, malaria screening was performed through a rapid diagnostic test in situ, and a blood sample was collected on filter paper. Highly sensitive molecular assays based on photo-induced electron transfer PCR (PET-PCR) were performed to detect the two species of Plasmodium circulating in Honduras: Plasmodium vivax and Plasmodium falciparum. In addition, the identification of the parasite species was verified by amplifying three genetic markers (Pvmsp3α, Pvmsp3ß, and Pfmsp1). Results: A total of 138 participants were recruited, mostly adult women. All individuals tested negative on the rapid diagnostic test. Positive results for malaria were detected by PET-PCR in 17 samples (12.3%). Most samples (12 out of 17) were amplified with a Ct value between 37 and 42, indicating very low parasitemias. Out of the 17 samples, 16 of them also showed amplification in the species assays. There were nine cases of P. falciparum infections and seven cases of P. vivax infections that were further confirmed by nested PCR (nPCR) of Pvmsp3 and Pfmsp1. Parasitemias ranged from 100 p/μL to less than 0.25 p/μL. One sample showed mixed infection. Conclusions: The existence of asymptomatic malaria reservoirs in Honduras can contribute to disease transmission and pose a challenge that may hinder elimination efforts, requiring public health authorities to modify surveillance strategies to identify the disease and treat this population accordingly. [ABSTRACT FROM AUTHOR]

Recent work on the biochemistry of N[SUB2] fixation including evidence supporting the current concept of electron transfer in N[SUB2] fixation is discussed. MgATP combines specifically with the Fe protein of nitrogenase, and lowers its potential sufficiently (near -400 mv) so that it can reduce the MoFe protein of nitrogenase. The MoFe protein serves as an electron sink to reduce all nitrogenase substrates. The potential loss of energy via release of H[SUB2] is discussed. There is a marked homology among the nitrogenase components from diverse sources, but the components from Clostridium pasteurianum often do not form catalytically active complexes with components from other organisms. The Fe protein from C. pasteurianum and the MoFe protein from Azotobacter vinelandii form a tightly binding, catalytically inactive complex. [ABSTRACT FROM AUTHOR]

The number of electric vehicles (EVs) is increasingly growing day by day and the charging infrastructure for covering this growing number of EVs should be developed. The construction of charging stations is one of the main solutions for supporting EVs while it costs huge investments for installation. Thus, this is not financially logical to invest in charging stations in remote areas with lower demands. An alternative way of constructing charging stations is to provide a peer-to-peer (P2P) energy exchange system in order to support out-of-charge EVs. In this paper, a private cloud-edge emergency energy trading framework is proposed to facilitate energy exchange among consumers and providers. Furthermore, a bidding system is suggested to encourage EVs with extra charges to exchange their energy. Moreover, a matching strategy for pairing consumers and providers is suggested in this paper that considers the benefit of both consumers and providers. In the proposed matching system, a measurement strategy is also suggested for considering the effect of the reliability and punctuality of the providers. To develop the accuracy and efficiency of the proposed framework, employing deep learning methods is also suggested in different layers of the framework. The performance of the proposed framework is evaluated on several case studies in the presence of EVs with realistic features to prove its efficiency, feasibility, and scalability. [ABSTRACT FROM AUTHOR]

The article presents information on several forthcoming research papers, which will be published in the coming issues of the European Journal of Biochemistry. Some of the topics of the papers are: lipolysis, biosynthesis, electron transfer, molecular weights, etc.

The genome—the source of life and platform of evolution—is continuously exposed to harmful factors, both extra- and intra-cellular. Their activity causes different types of DNA damage, with approximately 80 different types of lesions having been identified so far. In this paper, the influence of a clustered DNA damage site containing imidazolone (Iz) or oxazolone (Oz) and 7,8-dihydro-8-oxo-2′-deoxyguanosine (OXOdG) on the charge transfer through the double helix as well as their electronic properties were investigated. To this end, the structures of oligo-Iz, d[A1Iz2A3OXOG4A5]*d[T5C4T3C2T1], and oligo-Oz, d[A1Oz2A3OXOG4A5]*d[T5C4T3C2T1], were optimized at the M06-2X/6-D95**//M06-2X/sto-3G level of theory in the aqueous phase using the ONIOM methodology; all the discussed energies were obtained at the M06-2X/6-31++G** level of theory. The non-equilibrated and equilibrated solvent–solute interactions were taken into consideration. The following results were found: (A) In all the discussed cases, OXOdG showed a higher predisposition to radical cation formation, and B) the excess electron migration toward Iz and Oz was preferred. However, in the case of oligo-Oz, the electron transfer from Oz2 to complementary C4 was noted during vertical to adiabatic anion relaxation, while for oligo-Iz, it was settled exclusively on the Iz2 moiety. The above was reflected in the charge transfer rate constant, vertical/adiabatic ionization potential, and electron affinity energy values, as well as the charge and spin distribution. It can be postulated that imidazolone moiety formation within the CDL ds-oligo structure and its conversion to oxazolone can significantly influence the charge migration process, depending on the C2 carbon hybridization sp2 or sp3. The above can confuse the single DNA damage recognition and removal processes, cause an increase in mutagenesis, and harm the effectiveness of anticancer therapy. [ABSTRACT FROM AUTHOR]

This paper aims to discover a novel composite material that has great potential for manufacturing high-performance supercapacitors suitable for diverse applications, such as electric vehicles, portable electronics, and stationary energy storage systems. Zeolitic imidazolate framework-8 (ZIF-8) doped by different concentrations up to 5 wt.% of nanosized Fe2O3 have been prepared (ZIF-8/Fe2O3). The effect of doping ratio 1, 3, and 5 wt.% on the structural and electrochemical properties of ZIF-8/Fe2O3 has been investigated. The structural characterization has been carried out using TGA, BET, XRD, and FTIR. The XRD analysis revealed that the crystalline size of our sample increased by approximately 16% as a result of doping ZIF-8 with 5 wt.% of Fe2O3. The structural analysis of the doped samples revealed that the material exhibited enhanced thermal stability and porosity, with an increase of approximately 105 m2/g. The introduction of doped nanometal oxides improved the capacitance value of ZIF-8 by significantly increasing its surface area. Additionally, the electron transport efficiency within ZIF-8/5 wt.% Fe2O3/electrode is increased. The Nyquist plot decreases as the doping of Fe2O3 increases. This indicates a decrease in the charge transfer resistance at the electrode–electrolyte interface, which is desired in applications such as batteries, fuel cells, or electrochemical sensors where faster electron transfer is needed for improved performance. [ABSTRACT FROM AUTHOR]

Prussian blue analogues (PBAs) have recently emerged as effective materials in different functional applications, ranging from energy storage to electrochemical water splitting, thence to more "traditional" heterogeneous catalysis. Their versatility is due to their open framework, compositional variety, and fast and efficient internal charge exchange, coupled with a self-healing ability that makes them unique. This review paper presents and discusses the findings of the last decade in the field of the catalytic and photocatalytic application of PBAs in water remediation (via the degradation of organic pollutants and heavy metal removal) and the catalytic oxidation of organics and production or organic intermediates for industrial synthesis. Analysis of the catalytic processes is approached from a critical perspective, highlighting both the achievements of the research community and the limits still affecting this field. [ABSTRACT FROM AUTHOR]

Chromium (Cr) contamination, widely present in the environment, poses a significant threat to both ecology and human health. Microbial remediation technology has become a hot topic in the field of heavy metal remediation due to its advantages, such as environmental protection, low cost, and high efficiency. This paper focused on using various characterization and analysis methods to investigate the bioreduction effect and mechanism of microorganisms on Cr(VI) under various influencing factors. The main contents and conclusions were as follows: Shewanella oneidensis MR-1 was selected as the target strain for studying its reduction of Cr(VI) at different inoculation amounts, temperatures, pH values, time intervals, etc. The results indicated that S. oneidensis MR-1 exhibited an optimal reduction effect on Cr(VI) at pH 7 and a temperature of 35 °C. Additionally, electron shuttles (ESs), including humic acid (HA) and 9,10-antraquinone-2,6-disulfonate (AQDS), were introduced into the degradation system to improve the reduction efficiency of S. oneidensis MR-1. Upon adding goethite further, S. oneidensis MR-1 significantly enhanced its reducing ability by converting Fe(III) minerals to Fe(II) and reducing Cr(VI) to Cr(III) during electron transfer. [ABSTRACT FROM AUTHOR]

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Bioelectrochemical systems (BESs) are an emerging technology for wastewater treatment and resource recovery. These systems facilitate electron transfer between microorganisms and electrodes, enabling their application in various fields, such as electricity production, bioremediation, biosensors, and biocatalysis. However, electrode biofilms, which play a critical role in BESs, face several challenges (e.g., a long acclimation period, low attached biomass, high electron transfer resistance, and poor tolerance and stability) that limit the development of this technology. Quorum sensing (QS) is a communication method among microorganisms that can enhance the performance of BESs by regulating electrode biofilms. QS regulation can positively impact electrode biofilms by enhancing extracellular electron transfer (EET), biofilm formation, cellular activity, the secretion of extracellular polymeric substances (EPS), and the construction of microbial community. In this paper, the characteristics of anode electrogenic biofilms and cathode electrotrophic biofilms in BESs, EET mechanisms, and the main factors affecting biofilm formation were summarized. Additionally, QS regulation mechanisms for biofilm formation, strategies for enhancing and inhibiting QS, and the application of QS regulation for electrode biofilms in BESs were systematically reviewed and discussed. This paper provides valuable background information and insights for future research and development of BES platforms based on QS regulation of electrode biofilms. [ABSTRACT FROM AUTHOR]

Shock boundary layers are regions bounded by a shock wave on the one side and tangential discontinuity on the other side. These boundary layers are commonly observed in astrophysics. For example, they exist in the regions of the interaction of the stellar winds with the surrounding interstellar medium. Additionally, the shock layers (SLs) are often penetrated by the flows of interstellar atoms, as, for instance, in the astrospheres of the stars embedded by the partially ionized interstellar clouds. This paper presents a simple toy model of an SL that aims to qualitatively describe the influence of charge exchange with interstellar hydrogen atoms on the plasma flow in astrospheric SLs. To clearly explore this effect, magnetic fields are neglected, and the geometry is kept as simple as possible. The model explains why the cooling of plasma due to charge exchange in the inner heliosheath leads to an increase in plasma density in front of the heliopause. It also demonstrates that the source of momentum causes changes in the pressure profile within the SL. The paper also discusses the decrease in plasma density near the astropause in the outer SL in the case of layer heating, which is particularly relevant in light of the Voyager measurements in the heliospheric SL. [ABSTRACT FROM AUTHOR]

The residue of chestnut processing generates a large amount of waste material, a resource not adequately exploited. The antioxidant and antitumoral properties of cold and hot water extracts from discarded pericarp of four chestnut Sardinian accessions and one marron variety were studied. The antioxidant capacity of the extracts was determined by spectrophotometric and electrochemical tests. The 1,1-diphenyl-2-pic-rylhydrazyl (DPPH) and 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) results were highly correlated with each other; likewise, a good correlation was found between Ferric Reducing Antioxidant Power (FRAP) and cyclic voltammetry (CV) values, both based on the direct transfer of electrons. The antiproliferative effect on normal cells (fibroblasts), and on colon (RKO and SW48) and breast (MCF7) cancer cells was evaluated. Additionally, this paper marks the first application of chestnut extracts to investigate their effects on melanoma (B16F10) cells. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test demonstrated that temperature and different extraction times significantly influenced the growth of cells, both normal and tumor. The fibroblast growth was significantly inhibited by moderate doses of cold extracts, while the GI50 values calculated for hot extracts were high, regardless of the accession or cultivar. An even more marked inhibitory action of the cold extracts was observed both on the growth of RKO and SW48 cells and on B16F10 melanoma cells. Otherwise, an extract concentration, both cold and hot, of no less than 243 µg mL−1 is required to achieve a 50% inhibition of MCF7 cell growth. [ABSTRACT FROM AUTHOR]

Although nano SiO2 exhibits excellent application potential in the field of oil and gas exploration and development, such as drilling fluid, enhanced oil/gas recovery, etc., it is prone to agglomeration and loses its effectiveness due to the action of cations in saline environments of oil and gas reservoirs. Therefore, it is crucial to study the mechanism of the change in energy between nano SiO2 and cations for its industrial application. In this paper, the effect of cations (Na+, K+, Ca2+, and Mg2+) on the surface energy of nano SiO2 particles is investigated from the perspective of molecular motion and electronic change by density functional theory. The results are as follows: Due to the electrostatic interactions, cations can migrate towards the surface of nano SiO2 particles. During the migration process, monovalent cations are almost unaffected by water molecules, and they can be directly adsorbed on the surface by nano SiO2 particles. However, when divalent cations migrate from a distance to the surface of nano SiO2 particles, they can combine with water molecules to create an energy barrier, which can prevent them from moving forward. When divalent cations break through the energy barrier, the electronic kinetic energy between them and nano SiO2 particles changes more strongly, and the electrons carried by them are more likely to break through the edge of the atomic nucleus and undergo charge exchange with nano SiO2 particles. The change in interaction energy is more intense, which can further disrupt the configuration stability of nano SiO2. The interaction energy between cations and nano SiO2 particles mainly comes from electrostatic energy, followed by Van der Waals energy. From the degree of influence of four cations on nano SiO2 particles, the order from small to large is as follows: K+ < Na+ < Mg2+ < Ca2+. The research results can provide a theoretical understanding of the interaction between nano SiO2 particles and cations during the application of nano SiO2 in the field of oil and gas exploration and development. [ABSTRACT FROM AUTHOR]

A metal-free carbon catalyst is a kind of oxygen reduction catalyst with great prospects. It is an important material with potential to replace the traditional Pt catalyst. In this paper, a kind of irregular and ultra-thin carbon nanosheet (K180M-300-900) with high catalytic activity was synthesized by hydrothermal calcination using okra as a biomass and NH4Cl as an N source. The prepared nitrogen-doped metal-free catalyst with high pyridine-N and graphitic-N provides an extremely large number of active sites and has certain lattice defects. Ultra-thin carbon nanosheets promote sufficient contact between the catalyst and electrolyte, promote the diffusion of oxygen, and result in a faster transfer rate of electrons. The initial potential and half-slope potential of K180M-300-900 are 0.99 V and 0.82 V, respectively, which are comparable to those of 20% Pt/C. In addition, the stability and methanol tolerance of this catalyst (K180M-300-900) are better than 20% Pt/C, so it has great development potential and application value. This result provides a new method to prepare metal-free carbon materials that will take the place of traditional Pt catalysts. [ABSTRACT FROM AUTHOR]

The article presents information on several forthcoming research papers, which will be published in the coming issues of the European Journal of Biochemistry. Some of the topics of the papers are: lipolysis, biosynthesis, electron transfer, molecular weights, etc.

This paper clarifies the correct transmission mechanism, misattributed in the previous research, of a hydrogenated amorphous silicon thin-film transistor (a-Si:H TFT) device. Complete drain current–gate voltage (${I}_{\text {D}}$ – ${V}_{\text {G}}$) transfer characteristics including the forward and backward gate sweeps (gate voltage carried out in the OFF-state $\to $ on-state and the ON-state $\to $ OFF-state) are performed, and the physics models of an energy-band schematic are clearly explained. This paper reveals that the ${I}_{\text {D}}$ – ${V}_{\text {G}}$ curve stretch-out behavior of the subthreshold region is due to the leakage of the Poole–Frenkel region. At the Poole–Frenkel regions, electrons transfer to the drain terminal, and holes remain in the valance band of the a-Si:H bulk. The remaining holes represent the positive voltage and cause the electron barrier height lowering. This causes an increase in subthreshold current of the subthreshold region. Finally, three experiments are performed to prove the correctness of these models, and the a-Si TFTs device improvement methods will be proposed to enhance the stability and performance of product of the a-Si TFTs. [ABSTRACT FROM AUTHOR]

The influence of electrode surface chemistry over biofilm growth was evaluated for photo-bioelectrocatalytic fuel cell. A consortium of photosynthetic bacteria was grown onto different electrodes designed with polyethylenimine (PEI) and multiwall carbon nanotubes as hydrophilic and hydrophobic modifier, respectively. The designed electrodes were loaded with 0.08, 0.17, and 0.33 μg/cm2 of PEI to change the hydrophilicity. However, 0.56, 0.72, and 0.83 mg/cm2 of multiwall carbon nanotubes were used to alter the hydrophobicity of the electrodes. The surface chemistry of electrode and bio-interaction was evaluated as a function of contact angle and biofilm formation. The results were compared with those obtained with a carbon paper electrode. The contact angle on the untreated electrode (carbon paper) was 118°, whereas for hydrophobic and hydrophilic electrodes, the maximum and minimum contact angles were 170° and 0°, respectively. Interestingly, the maximum biofilm growth (0.2275 g, wet basis) was observed on highly hydrophobic surface; however, the maximum electrochemical performance (246 mV) was shown by the most hydrophilic electrode surface. PEI-based electrode with good biofilm formation showed comparatively higher electrogenic activity. [ABSTRACT FROM AUTHOR]