BINA

Electro-oxidation of urea offers tremendous opportunity for the economical hydrogen production option owing to its lower thermodynamic potential barriers. Slower reaction rate and multiple gas desorption steps hinder the implementation of urea-based fuel cells, and thus understanding the urea oxidation process is key for the commercialization of this technology. In this report, we systematically examined the electrocatalytic urea oxidation activity of nickel-based model catalysts such as Ni12P5 and Ni(OH)2 in an alkaline medium at a fixed urea concentration of 0.33 M using electrochemical impedance spectroscopy (EIS). Ni12P5 and Ni(OH)2 require potentials of 0.51 and 0.54 V vs Hg/HgO, respectively, to achieve a current density of 10 mA cm–2. The origin of the catalytic activity difference of the urea oxidation reaction (UOR) between these two Ni catalysts is briefly analyzed using nondestructive in situ EIS. We …

In their recent publication, Khatri et al.[1] describe an immunoglobulin germline gene database inferred from shortread genomic sequence data derived from five superpopulations. The development of methods for the compilation of more complete and accurate germline gene databases would be an important achievement, but we do not believe that this has been achieved. Existing databases are clearly incomplete. Germline sequences differ substantially between subjects, and alleles found in some populations may be absent in others. Existing databases are likely biased towards alleles found in European populations and may lack many sequences found in understudied populations [2]. Improved, properly designed and curated germline gene databases are therefore needed for analysis of antibody repertoires.Extensive efforts are under way to better document germline genes, and the study by Khatri et al …

Electrolyzer technologies are essential for the Hydrogen Economy scheme, and in order to drive the hydrogen production price down, their lifetimes need to be extended. One important parameter that has not been given enough attention in this context is catalyst durability. In this work, a durable platinum-group metal-free catalyst was developed for the hydrogen evolution reaction based on a porous, high-surface area molybdenum carbide aerogel. The molybdenum oxide aerogel was synthesized by a sol–gel method and carburized by methane treatment. A three-dimensional molybdenum carbide network was obtained by reacting the molybdenum oxide aerogel with a CH4/H2 mixture at 700 °C. Surface area measurement confirmed a substantial increase in the volume of micropores in the transition from oxide to carbide. The carbide aerogel has low density (<0.4 g/mL) with a relatively high surface area of 109 m2 …

This study presents a partially coherent illumination based (PCI-based) SIM apparatus for dual-modality (phase and fluorescent) microscopic imaging. The partially coherent illumination (PCI) is generated by placing a rotating diffuser on a monochromatic laser beam, which suppresses speckle noise in the dual-modality images and endows the apparatus with sound sectioning capability. With this system, label-free quantitative phase and super-resolved/sectioned fluorescent images can be obtained for the same sample. We have demonstrated the superiority of the system in phase imaging of transparent cells with high endogenous contrast and in a quantitative manner. In the meantime, we have also demonstrated fluorescent imaging of fluorescent beads, rat tail crosscut, wheat anther, and hibiscus pollen with super-resolution and optical sectioning. We envisage that the proposed method can be applied to many …

Catheter-associated urinary tract infections (CAUTIs), caused by biofilms, are the most frequent health-care associated infections. Novel antibiofilm coatings are needed to increase the urinary catheters' life-span, decrease the prevalence of CAUTIs and reduce the development of antimicrobial resistance. Herein, antibacterial zinc oxide nanoparticles (ZnO NPs) were decorated with a biofilm matrix-degrading enzyme amylase (AM) and simultaneously deposited onto silicone urinary catheters in a one-step sonochemical process. The obtained nano-enabled coatings inhibited the biofilm formation of Escherichia coli and Staphylococcus aureus by 80% and 60%, respectively, for up to 7 days in vitro in a model of catheterized bladder with recirculation of artificial urine due to the complementary mode of antibacterial and antibiofilm action provided by the NPs and the enzyme. Over this period, the coatings did not …

In capacitive deionization (CDI), coion repulsion and Faradaic reactions during charging reduce the charge efficiency (CE), thus limiting the salt adsorption capacity (SAC) and energy efficiency. To overcome these issues, membrane CDI (MCDI) based on the enhanced permselectivity of the anode and cathode is proposed using the ion-exchange polymer as the independent membrane or coating. To develop a novel and cost-effective MCDI system, we fabricated an integrated membrane electrode using a thin layer of the inorganic ion-exchange material coated on the activated carbon (AC) electrode, which effectively improves the ion selectivity. Montmorillonite (MT, Al2O9Si3) and hydrotalcite (HT, Mg6Al2(CO3)(OH)16·4H2O) were selected as the main active anion- and cation-exchange materials, respectively, for the cathode and anode. The HT–MT MCDI system employing HT–AC and MT–AC electrodes …

Nanodisc technology was implemented as a platform for voltage nanosensors. A fluorescence (Förster) resonance energy transfer (FRET)- based voltage-sensing scheme employing fluorescent nanodiscs and the hydrophobic ion dipicrylamine was developed and utilized to optically record membrane potentials on the single-nanodisc level. Ensemble and single-nanosensor recordings were demonstrated for HEK293 cells and primary cortical neuron cells. Conjugation of nanodiscs to anti-GABAA antibodies allowed for site-specific membrane potential measurements from postsynaptic sites.

By means of electrocatalytic tests, surface-science techniques and density functional theory, we unveil the physicochemical mechanisms ruling the electrocatalytic activity of recently discovered mitrofanovite (Pt3Te4) mineral. Mitrofanovite represents a very promising electrocatalyst candidate for energy-related applications, with a reduction of costs by 47% compared to pure Pt and superior robustness to CO poisoning. We show that Pt3Te4 is a weak topological metal with the invariant, exhibiting electrical conductivity (∼4 × 106 S/m) comparable with pure Pt. In hydrogen evolution reaction (HER), the electrode based on bulk Pt3Te4 shows a very small overpotential of 46 mV at 10 mA cm–2 and a Tafel slope of 36–49 mV dec–1 associated with the Volmer–Heyrovsky mechanism. The outstanding ambient stability of Pt3Te4 also provides durability of the electrode and long-term stability of its efficient catalytic …

Li and Mn-rich nickel cobalt manganese oxide (LMR-NCM) is one of the most promising cathode materials for realizing next-generation Li-ion batteries due to its high specific capacity of >250 mA h g–1 and operating potential > 4.5 V. Nevertheless, being plagued by severe capacity fading and voltage decay, the commercialization of LMR-NCM appears to be a distant goal. The anionic activity of oxygen and associated phase transformations are the reasons behind the unstable electrochemical performance. The tendency of LMR-NCM to react with CO2 and moisture further makes it prone to interfacial instability and degradation. Here, we report a neoteric method to mitigate the stability issues and improve the electrochemical performance of LMR-NCM by changing the electronic configuration of constituting O and transition metals via diethylzinc-assisted atomic surface reduction (Zn-ASR) using an extremely facile …

A key issue in the development of sustainable Na-ion batteries (NIBs) is the stability of the electrolyte solution and its ability to form effective passivation layers on both cathode and anode. In this regard, the use of fluorine-based additives is considered a promising direction for improving electrode performance. Fluoroethylene carbonate (FEC) and trans-difluoroethylene carbonate (DFEC) were demonstrated as additives or cosolvents that form effective passivating surface films in Li-ion batteries. Their effect is evaluated for the first time with cathodes in NIBs. By application of systematic electrochemical and postmortem investigations, the role of fluorinated additives in the good performance of Na0.44MnO2 (NMO) cathodes was deciphered. Despite the significant improvement in the performance of Li-ion cells enabled by the use of FEC and FEC + DFEC, the highest stability for NIBs was observed when only FEC was …

In the original publication of this article, in the penultimate sentence of the legend to Fig 3, there were errors in identifying coloured lines. These should read:“Direct polarization (blue line) samples all the Si atoms in the sample, while 1H-crosspolarization (black line) samples Si atoms in proximity to protons.” instead of “:“Direct polarization (black line) samples all the Si atoms in the sample, while 1H-cross-polarization (blue line) samples Si atoms in proximity to protons.” This error has now been corrected online.

We present a fluorescence fluctuation image correlation analysis method that can rapidly and simultaneously measure the diffusion coefficient, photoblinking rates, and fraction of diffusing particles of fluorescent molecules in cells. Unlike other image correlation techniques, we demonstrated that our method could be applied irrespective of a non-uniformly distributed, immobile blinking fluorophore population. This allows us to measure blinking and transport dynamics in complex cell morphologies, a benefit for a range of super-resolution fluorescence imaging approaches that rely on probe emission blinking. Furthermore, we showed that our technique could be applied without directly accounting for photobleaching. We successfully employed our technique on several simulations with realistic EMCCD noise and photobleaching models, as well as on Dronpa-C12 labeled beta-actin in living NIH/3T3 and HeLa cells …

Using X-ray scattering from binary mixtures of [C n mim][NTf 2] room temperature ionic liquids (RTILs) with n= 8, 12 we study their nanoscale layering and its evolution with temperature T and mole fraction x of [C 8 mim][NTf 2]. The layers’ lateral structure, dominated by the common headgroups’ Coulomb interaction in the layer’s polar slab, and by the chain-chain van der Waals interaction in the apolar slab, hardly changes. However, the longitudinal layer spacing, d I, decreases with x, exhibiting domination by [C 12 mim][NTf 2] at least up to x≈ 0.5. The layering order’s range decreases uniformly with x. d I is found to deviate positively from an ideal mixture spacing by up to≲ 5%. The lateral spacings’ deviations are 10-fold smaller, implying the nanoscale excess volume to be also≲ 5%, 100-fold larger than those obtained from macroscopic molar density measurements. This gap is probably bridged at the larger length …

We present random lasing action on a two dimensional (2D) active surface incorporated with randomly distributed air holes: responsible for coherent multiple scattering and couple out the radiation normal to surface.

Rechargeable batteries based on Mg metal anodes may be a promising alternative to current Li‐ion battery systems. However, the development of practical rechargeable Mg batteries (RMBs) is hindered by the absence of cathode materials that can reversibly intercalate Mg ions with a reasonably fast kinetic, while still exhibiting high capacity and high working voltages. In this minireview we summarize our recent progress in understanding cathodes/electrolyte solutions interfaces in non‐aqueous Mg systems. While most studies in the field of cathode materials for RMBs focus on the solid‐state diffusion phenomena of the bare Mg ion within the solid hosts, this minireview summarizes several important findings that demonstrate how the electrochemical response of the cathode material is also significantly influenced by the solution chemistry and structure. We provide a comprehensive description of the sequential …

A key issue in the development of sustainable Na-ion batteries (NIBs) is the stability of the electrolyte solution and its ability to form effective passivation layers on both cathode and anode. In this regard, the use of fluorine-based additives is considered a promising direction for improving electrode performance. Fluoroethylene carbonate (FEC) and trans-difluoroethylene carbonate (DFEC) were demonstrated as additives or cosolvents that form effective passivating surface films in Li-ion batteries. Their effect is evaluated for the first time with cathodes in NIBs. By application of systematic electrochemical and postmortem investigations, the role of fluorinated additives in the good performance of Na0.44MnO2 (NMO) cathodes was deciphered. Despite the significant improvement in the performance of Li-ion cells enabled by the use of FEC and FEC + DFEC, the highest stability for NIBs was observed when only FEC was …

In capacitive deionization (CDI), coion repulsion and Faradaic reactions during charging reduce the charge efficiency (CE), thus limiting the salt adsorption capacity (SAC) and energy efficiency. To overcome these issues, membrane CDI (MCDI) based on the enhanced permselectivity of the anode and cathode is proposed using the ion-exchange polymer as the independent membrane or coating. To develop a novel and cost-effective MCDI system, we fabricated an integrated membrane electrode using a thin layer of the inorganic ion-exchange material coated on the activated carbon (AC) electrode, which effectively improves the ion selectivity. Montmorillonite (MT, Al2O9Si3) and hydrotalcite (HT, Mg6Al2(CO3)(OH)16·4H2O) were selected as the main active anion- and cation-exchange materials, respectively, for the cathode and anode. The HT–MT MCDI system employing HT–AC and MT–AC electrodes obtained a CE of 90.5% and an SAC of 15.8 mg g–1 after 100 consecutive cycles (50 h); these values were considerably higher than those of the traditional CDI system employing pristine AC electrodes (initially, a CE of 55% and an SAC of 10.2 mg g–1, which attenuated continuously to zero, and even “inverted work” occurs after 50 h, i.e., desorption during charging and adsorption during discharging). The HT–MT MCDI system showed moderate tolerance to organic matters during desalination and retained 84% SAC and 89% CE after 70 cycles in 50–200 mg L–1 sodium alginate. This study demonstrates a simple and cost-effective method for fabricating high-CE electrodes for desalination with great application potential.

By means of electrocatalytic tests, surface-science techniques and density functional theory, we unveil the physicochemical mechanisms ruling the electrocatalytic activity of recently discovered mitrofanovite (Pt3Te4) mineral. Mitrofanovite represents a very promising electrocatalyst candidate for energy-related applications, with a reduction of costs by 47% compared to pure Pt and superior robustness to CO poisoning. We show that Pt3Te4 is a weak topological metal with the invariant, exhibiting electrical conductivity (∼4 × 106 S/m) comparable with pure Pt. In hydrogen evolution reaction (HER), the electrode based on bulk Pt3Te4 shows a very small overpotential of 46 mV at 10 mA cm–2 and a Tafel slope of 36–49 mV dec–1 associated with the Volmer–Heyrovsky mechanism. The outstanding ambient stability of Pt3Te4 also provides durability of the electrode and long-term stability of its efficient catalytic …

In many sensitive assays, target molecules are tagged using fluorescently labeled probes and captured using magnetic beads. Here, we introduce an optical modulation biosensing (OMB) system, which aggregates the beads into a small detection area and separates the signal from the background noise by manipulating the laser beam in and out of the cluster of beads. Using the OMB system to detect human interleukin-8, we demonstrated a limit of detection of 0.02 ng/L and a 4-log dynamic range. Using Zika-positive and healthy individuals’ serum samples, we show that the OMB-based Zika IgG serological assay has 96% sensitivity and 100% specificity.

Rapid and sensitive detection of human pathogens, such as the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), is an urgent and challenging task for clinical laboratories. Currently, the gold standard test for SARS-CoV-2-specific ribonucleic acid (RNA) is based on reverse transcription quantitative polymerase chain reaction (RT-qPCR), which relies on target amplification by Taq polymerase and uses a fluorescent resonance energy transfer (FRET)-based hydrolysis probe. Although this method is accurate and specific, it is also time consuming. To rapidly detect the presence of the viral RNA in clinical samples, we describe a new molecular assay that combines a highly sensitive magnetic modulation biosensing (MMB) system, rapid thermal cycling, and a modified double-quenched hydrolysis probe. Using in vitro transcribed SARS-CoV-2 RNA targets spiked in PCR-grade water, we found that the …