SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Michael Faraday

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We have found that the addition of tin nanoparticles to a silicon-based anode provides dramatic improvements in performance in terms of both charge capacity and cycling stability. Using a simple procedure and off-the-shelf additives and precursors, we developed a structure in which the tin nanoparticles are segregated at the interface between the silicon-containing active layer and the solid electrolyte interface. Even a minor addition of tin, as small as ∼2% by weight, results in a significant decrease in the anode resistance, as confirmed by electrochemical impedance spectroscopy. This leads to a decrease in charge transfer resistance, which prevents the formation of electrically inactive “dead spots” in the anode structure and enables the effective participation of silicon in the lithiation reaction.

Concepts: Cathode, Michael Faraday, Electrochemistry, Aluminium, Battery, Electrolyte, Electrode, Anode

28

Since Michael Faraday and Joseph Henry made their great discovery of electromagnetic induction, there have been continuous developments in electrical power generation. Most people today get electricity from thermal, hydroelectric, or nuclear power generation systems, which use this electromagnetic induction phenomenon. Here we propose a new method for electrical power generation, without using electromagnetic induction, by mechanically modulating the electrical double layers at the interfacial areas of a water bridge between two conducting plates. We find that when the height of the water bridge is mechanically modulated, the electrical double layer capacitors formed on the two interfacial areas are continuously charged and discharged at different phases from each other, thus generating an AC electric current across the plates. We use a resistor-capacitor circuit model to explain the results of this experiment. This observation could be useful for constructing a micro-fluidic power generation system in the near future.

Concepts: Electromagnetism, Electric charge, Michael Faraday, Electricity, Nuclear power, Inductor, Inductance, Electrical generator

28

Site-selective sequential coupling reactions directed toward bis(diaryl)butadiynes are described. The reaction site could be controlled completely by the on/off application of electricity. The electro-oxidative homo-coupling of terminal alkynes (electricity ON) and the subsequent Suzuki-Miyaura coupling (electricity OFF) afforded bis(diaryl)butadiynes in high yields. The obtained 1,4-bis(diaryl)butadiynes could be converted to a 2,5-bis(diaryl)thiophene derivative, which exhibited blue fluorescence.

Concepts: Michael Faraday, Electric current, Electrochemistry, Alkyne, Heck reaction, Suzuki reaction, Sonogashira coupling, Cadiot-Chodkiewicz coupling

27

How to mitigate membrane fouling remains a critical challenge for widespread application of membrane bioreactors. Herein, an antifouling electrochemical membrane bioreactor (EMBR) was developed based on in-situ utilization of the generated electricity for fouling control. In this system, a maximum power density of 1.43 W/m(3) and a current density of 18.49 A/m(3) were obtained. The results demonstrate that the formed electric field reduced the deposition of sludge on membrane surface by enhancing the electrostatic repulsive force between them. The produced H2O2 at the cathode also contributed to the fouling mitigation by in-situ removing the membrane foulants. In addition, 93.7% chemical oxygen demand (COD) removal and 96.5% [Formula: see text] removal in average as well as a low effluent turbidity of below 2 NTU were achieved, indicating a good wastewater treatment performance of the EMBR. This work provides a proof-of-concept study of an antifouling MBR with high wastewater treatment efficiency and electricity recovery, and implies that electrochemical control might provide another promising avenue to in-situ suppress the membrane fouling in MBRs.

Concepts: Electromagnetism, Electric charge, Michael Faraday, Magnetic field, Electric current, Water pollution, Wastewater, Fouling

27

Acenes consist of linearly annulated benzene rings. Their reactivity increases quickly with increasing chain length. Therefore acenes longer than pentacene are very sensitive towards oxygen in the presence of light and thus these molecules have not been well studied or have remained elusive in spite of synthetic efforts dating back to the 1930s. This review gives an historical account of the development of the chemistry of acenes larger than pentacene and summarizes the recent progress in the field including strategies for stabilization of higher acenes up to nonacene.

Concepts: Michael Faraday, Molecule, Gasoline, Chemical substance, Benzene, Solvent, Distillation, 1930s

27

During the last few years, intensive research efforts have been directed toward the application of several highly efficient light-harvesting photosynthetic proteins, including reaction centers (RCs), photosystem I (PSI), and photosystem II (PSII), as key components in the light-triggered generation of fuels or electrical power. This review highlights recent advances for the nano-engineering of photo-bioelectrochemical cells through the assembly of the photosynthetic proteins on electrode surfaces. Various strategies to immobilize the photosynthetic complexes on conductive surfaces and different methodologies to electrically wire them with the electrode supports are presented. The different photoelectrochemical systems exhibit a wide range of photocurrent intensities and power outputs that sharply depend on the nano-engineering strategy and the electroactive components. Such cells are promising candidates for a future production of biologically-driven solar power.

Concepts: Photosynthesis, Electric charge, Michael Faraday, Electricity, Photosystem, Photosystem I, Photosystem II, Photosynthetic reaction centre

27

Layered P2-Na(x)[Ni(1/3)Mn(2/3)]O(2) (0 < x < 2/3) is investigated as a cathode material for Na-ion batteries. A combination of first principles computation, electrochemical and synchrotron characterizations is conducted to elucidate the working mechanism for the improved electrochemical properties. The reversible phase transformation from P2 to O2 is observed. New configurations of Na-ions and vacancy are found at x = 1/3 and 1/2, which correspond to the intermediate phases upon the electrochemical cycling process. The mobility of Na-ions is investigated using the galvanostatic intermittent titration technique (GITT) and the Na diffusion barriers are calculated by the Nudged Elastic Band (NEB) method. Both techniques prove that the mobility of Na-ions is faster than Li-ions in the O3 structure within the 1/3 < x < 2/3 concentration region. Excellent cycling properties and high rate capability can be obtained by limiting the oxygen framework shift during P2-O2 phase transformation, suggesting that this material can be a strong candidate as a sustainable low-cost Na-ion battery cathode.

Concepts: Michael Faraday, Battery, Electrolyte, Electrode, Electrolysis, Anode, Galvanic cell, Electrolytic cell

26

Oxidation-resistant copper nanowires (Cu NWs) are synthesized by a polyol reduction method. These Cu NWs show excellent oxidation resistance, good dispersibility, and have a low sintering temperature. A Cu NW-based flexible, foldable, and free-standing electrode is fabricated by filtration and a sintering process. The electrode also exhibits high electrical conductivity even bending, folding, and free-standing.

Concepts: Michael Faraday, Redox, Electrochemistry, Aluminium, Copper, Electrochemical cell, Electrolysis, Electrical conductivity

25

The peptide drug enfuvirtide (T20) is the only HIV-1 fusion inhibitor in clinical use, but it easily induces drug-resistance, calling for new strategies for developing next-generation drugs. On the basis of the M-T hook structure, we recently developed highly potent short-peptide HIV-1 fusion inhibitors (MTSC22 and HP23), which mainly target the conserved gp41 pocket and possess high genetic barriers to resistance. Here, we focused on the selection and characterization of HIV-1 escape mutants to MTSC22, which revealed new resistance pathways and mechanisms. Two mutations, E49K and L57R, located at the inhibitor-binding site, and two mutations, N126K and E136G, located at the C-terminal heptad repeat region of gp41, were identified as conferring high resistance either singly or in combinations. While E49K reduced the C-terminal binding of inhibitors via an electrostatic repulsion, L57R dramatically disrupted the N-terminal binding of M-T hook structure and pocket-binding domain. Different from E49K and N126K that enhanced the stability of endogenous viral six-helical bundle core (6-HB), L57R and E136G conversely destabilized the 6-HB structure. We also demonstrated that both primary and secondary mutations caused the structural changes of 6-HB and severely impaired the ability of HIV-1 entry. Collectively, our data provide novel insights into the mechanisms of short-peptide fusion inhibitors targeting the gp41 pocket site and help our understanding for the structure and function of gp41 and HIV-1 evolution.

Concepts: HIV, Protein, Michael Faraday, Electrostatics, Electric field, CCR5, Inhibitor, Entry inhibitor

25

This paper reports a novel approach for the simple assays of cell apoptosis using electrochemical technique. In this study, caspase-3 activity, which was detected with differential plus voltammetry (DPV) as an alternative to conventional spectrometry approach, was employed as an indicator of cell apoptosis and, while an acetylated peptide Ac-GGHDEVDHGGGC was used as the blocked substrate. In the presence of casepase-3, the hydrolysis of blocked peptide might release active amine groups, which could covalently conjugate with graphene oxide. Therefore, electroactive methylene blue molecules could be further attached to the electrode surface through π-π stacking and electrostatic interactions. Using this proposed new method, a very sensitive detection of caspase-3 could be achieved with a low detection limit of 0.06pg/mL, and a new method for sensitive detection of cell apoptosis was developed. Moreover, we have successfully used this new method to detect cell apoptosis with human pulmonary carcinoma A549 cell after apoptosis inducing.

Concepts: Protein, Michael Faraday, Apoptosis, Electrochemistry, Electrolyte, Electrode, Electrochemical cell, XIAP