Separator Design Strategies to Advance Rechargeable Aqueous Zinc Ion Batteries.

With the increasing demand for low-cost and high-safety portable batteries, aqueous zinc-ion batteries (ZIBs) have been regarded as a potential alternative to the lithium-ion batteries, bringing about extensive research dedicated in the exploration of high-performance and highly reversible ZIBs. Although separators are generally considered as non-active components in conventional research on ZIBs, advanced separators designs seem to offer effective solutions to the majority of issues within ZIBs system. These issues encompass concerns related to the zinc anode, cathode, and electrolyte. Initially, we delve into the origins and implications of various inherent problems within the ZIBs system. Subsequently, we present the latest research advancements in addressing these challenges through separators engineering. This includes a comprehensive, detailed exploration of various strategies, coupled with instances of advanced characterizations to provide a more profound insight into the mechanisms that influence the separators. Finally, we undertake a multi-criteria evaluation, based on application standards for diverse substrate separators, while proposing guiding principles for the optimal design of separators in zinc batteries. This review aims to furnish valuable guidance for the future development of advanced separators, thereby nurturing progress in the field of ZIBs.

Building Sustainable Saturated Fatty Acid-Zinc Interfacial Layer toward Ultra-Stable Zinc Metal Anodes.

The commercialization pace of aqueous zinc batteries (AZBs) is seriously limited due to the uncontrolled dendrite growth and severe corrosion reaction of the zinc anode. Herein, a universal and extendable saturated fatty acid-zinc interfacial layer strategy for modulating the interfacial redox process of zinc toward ultrastable Zn metal anodes is proposed. The in situ complexing of saturated fatty acid-zinc interphases could construct an extremely thin zinc compound layer with continuously constructed zincophilic sites which kinetically regulates Zn nucleation and deposition behaviors. Furthermore, the multifunctional interfacial layer with internal hydrophobic carbon chains as a protective layer is efficient to exclude active water molecules from the surface and efficiently inhibit the surface corrosion of zinc. Consequently, the modified anode shows a long cycle life of over 4000 h at 5 mA cm-2. In addition, the assembled Zn||V2O5 full cells based on modified zinc anodes have excellent rate performance and long cycle stability.

[Prevention of the development of geriatric syndromes and acute functional deficiency in patients with frailty.]

One of the most difficult tasks in medical practice is pharmacotherapy in elderly and senile patients. The complexity of pharmacotherapy in elderly patients is due to age-related physiological changes, high frequency of multimorbidity. The age of patients no longer precludes surgical intervention, and surgical procedures are often performed on elderly patients with complex comorbidities. Over the past 15 years, the number of emergency hospitalizations has increased significantly worldwide.

Amino-Functionalized Interfacial Layer Enables an Ultra-Uniform Amorphous Solid Electrolyte Interphase for High-Performance Aqueous Zinc-Based Batteries.

Aqueous rechargeable zinc-based batteries (ZBBs) are emerging as desirable energy storage systems because of their high capacity, low cost, and inherent safety. However, the further application of ZBBs still faces many challenges, such as the issues of uncontrolled dendrite growth and severe parasitic reactions occurring at the Zn anode. Herein, an amino-grafted bacterial cellulose (NBC) film is prepared as artificial solid electrolyte interphase (SEI) for the Zn metal anodes, which can significantly reduce zinc nucleation overpotential and lead to the dendrite-free deposition of Zn metal along the (002) crystal plane more easily without any external stimulus. More importantly, the chelation between the modified amino groups and zinc ions can promote the formation of an ultra-even amorphous SEI upon cycling, reducing the activity of hydrate ions, and inhibiting the water-induced side reactions. As a result, the Zn||Zn symmetric cell with NBC film exhibits lower overpotential and higher cyclic stability. When coupled with the V2 O5 cathode, the practical pouch cell achieves superior electrochemical performance over 1000 cycles.

Efficient Suppression of Dendrites and Side Reactions by Strong Electrostatic Shielding Effect via the Additive of Rb2 SO4 for Anodes in Aqueous Zinc-Ion Batteries.

Aqueous zinc-ion batteries (AZIBs) have attracted considerable attention due to their low cost and environmental friendliness. However, the rampant dendrite growth and severe side reactions during plating/stripping on the surface of zinc (Zn) anode hinder the practicability of AZIBs. Herein, an effective and non-toxic cationic electrolyte additive of Rb2 SO4 is proposed to address the issues. The large cation of Rb+ is preferentially adsorbed on the surface of Zn metal to induce a strong shielding effect for realizing the lateral deposition of Zn2+ ions along the Zn surface and isolating water from Zn metal to effectively inhibit side reactions. Consequently, the Zn||Zn symmetric cell with the addition of 1.5 mm Rb2 SO4 can cycle more than 6000 h at 0.5 mA cm-2 /0.25 mAh cm-2 , which is 20 times longer than that without Rb2 SO4 . Besides, the Zn||Cu asymmetric cell with Rb2 SO4 achieves a very high average Coulombic efficiency of 99.16% up to 500 cycles. Moreover, the electrolyte with Rb2 SO4 well matches with the VO2 cathode, achieving high initial capacity of 412.7 mAh g-1 at 5 A g-1 and excellent cycling stability with a capacity retention of 71.6% at 5 A g-1 after 500 cycles for the Zn//VO2 full cell.

Surfactant Additives Containing Hydrophobic Fluorocarbon Chains and Hydrophilic Sulfonate Anion for Highly Reversible Zn Anode.

Aqueous zinc-ion batteries (AZIBs) show enormous potential as a large-scale energy storage technique. However, the growth of Zn dendrites and serious side reactions occurring at the Zn anode hinder the practical application of AZIBs. For the first time, we reported a fluorine-containing surfactant, i.e., potassium perfluoro-1-butanesulfonate (PPFBS), as an additive to the 2 M ZnSO4 electrolyte. Benefitting from its hydrophilic sulfonate anion and hydrophobic long fluorocarbon chain, PPFBS can promote the uniform distribution of Zn2+ flux at the anode/electrolyte interface, allowing the Zn/Zn cell to cycle for 2200 h. Furthermore, PPFBS could inhibit side reactions due to the existence of the perfluorobutyl sulfonate (C4F9SO3-) adsorption layer and the presence of C4F9SO3- in the solvation structure of Zn2+. The former can reduce the amount of H2O molecules and SO42- in contact with the Zn anode and C4F9SO3- entering the Zn2+-solvation structure by replacing SO42-. The Zn/Cu cell exhibits a superior average CE of 99.47% over 500 cycles. When coupled with the V2O5 cathode, the full cell shows impressive cycle stability. This work provides a simple, effective, and economical solution to the common issues of the Zn anode.

Epimerisation in Peptide Synthesis.

Epimerisation is basically a chemical conversion that includes the transformation of an epimer into another epimer or its chiral partner. Epimerisation of amino acid is a side reaction that sometimes happens during peptide synthesis. It became the most avoided reaction because the process affects the overall conformation of the molecule, eventually even altering the bioactivity of the peptide. Epimerised products have a high similarity of physical characteristics, thus making it difficult for them to be purified. In regards to amino acids, epimerisation is very important in keeping the chirality of the assembled amino acids unchanged during the peptide synthesis and obtaining the desirable product without any problematic purification. In this review, we report several factors that induce epimerisation during peptide synthesis, including how to characterise and affect the bioactivities. To avoid undesirable epimerisation, we also describe several methods of suppressing the process.

Regulated Ion/Electron-Conducting Interphase Enables Stable Zinc-Metal Anodes for Aqueous Zinc-Ions Batteries.

Metallic Zinc (Zn) is considered as a remarkably promising anode for aqueous Zn-ion batteries due to its high volumetric capacity and low redox potential. Unfortunately, dendritic growth and severe side reactions destabilizes the electrode/electrolyte interface, and ultimately reduce the electrochemical performance. Here, an artificial protective layer (APL) with a regulated ion and electron-conducting interphase is constructed on the Zn-metal anode to provide excellent interfacial stability in high-rate cycling. The superior ionic and moderate electronic conductivity of the APL derives from the co-embedding of MXene and Zn(CF3 SO3 )2 salts into the polyvinyl alcohol hydrogel, which enables a synergistic effect of local current density reduction during plating and ion transport acceleration during stripping for Zn anode. Furthermore, the high Young's modulus of the protective layer and dendrite-free deposition morphology during cycling suppresses hydrogen evolution reactions (2.5 mmol h-1 cm-2 ) and passivation. As a result, in symmetrical cell tests, the modified battery presents a stable life of over 2000 cycles at ultra-high current density of 20 mA cm-2 . This research presents a new insight into the formation and regulation of stable electrode-electrolyte interface for the Zn-metal anode.

Proton-Reservoir Hydrogel Electrolyte for Long-Term Cycling Zn/PANI Batteries in Wide Temperature Range.

Advanced aqueous batteries are promising for next generation flexible devices owing to the high safety, yet still requiring better cycling stability and high capacities in wide temperature range. Herein, a polymeric acid hydrogel electrolyte (PAGE) with 3 M Zn(ClO4 )2 was fabricated for high performance Zn/polyaniline (PANI) batteries. With PAGE, even at -35 °C the Zn/Zn symmetrical battery can keep stable for more than 1 500 h under 2 mA cm-2 , and the Zn/PANI battery can provide ultra-high stable specific capacity of 79.6 mAh g-1 for more than 70 000 cycles at 15 A g-1 . This can be mainly ascribed to the -SO3 - H+ function group in PAGE. It can generate constant protons and guide the (002) plane formation to accelerate the PANI redox reaction kinetics, increase the specific capacity, and suppress the side reaction and dendrites. This proton-supplying strategy by polymeric acid hydrogel may further propel the development of high performance aqueous batteries.

Alleviating Side Reactions on Zn Anodes for Aqueous Batteries by a Cell Membrane Derived Phosphorylcholine Zwitterionic Protective Layer.

Aqueous zinc (Zn) ion batteries are attractive for next generation batteries with high safety, yet their applications are still hindered by the uncontrollable dendrite formation and side reactions on Zn anode. Here, a polyzwitterion protective layer (PZIL) was engineered by polymerizing 2-methacryloyloxyethyl phosphorylcholine (MPC) in carboxymethyl chitosan (CMCS), which renders the following merits: the choline groups of MPC can preferentially adsorb onto Zn metal to avoid side reactions; the charged phosphate groups chelate with Zn2+ to regulate the solvation structure, further improving side reaction inhibition; the Hofmeister effect between ZnSO4 and CMCS can enhance the interfacial contact during electrochemical characterization. Consequently, the symmetrical Zn battery with PZIL can keep stable for more than 1000 hours under the ultra-high current density of 40 mA cm-2 . The PZIL confers the Zn/MnO2 full battery and Zn/active carbon (AC) capacitor with stable cycling performance under high current density.

Reaction Mechanism for the Removal of NOx by Wet Scrubbing Using Urea Solution: Determination of Main and Side Reaction Paths.

Secondary problems, such as the occurrence of side reactions and the accumulation of by-products, are a major challenge in the application of wet denitrification technology through urea solution. We revealed the formation mechanism of urea nitrate and clarified the main and side reaction paths and key intermediates of denitrification. Urea nitrate would be separated from urea absorption solution only when the concentration product of [urea], [H+] and [NO3-] was greater than 0.87~1.22 mol3/L3. The effects of the urea concentration (5-20%) and reaction temperature (30-70 °C) on the denitrification efficiency could be ignored. Improving the oxidation degree of the flue gas promoted the removal of nitrogen oxides. The alkaline condition was beneficial to the dissolution process, while the acidic condition was beneficial to the reaction process. As a whole, the alkaline condition was the preferred process parameter. The research results could guide the optimization of process conditions in theory, improve the operation efficiency of the denitrification reactor and avoid the occurrence of side reactions.

Influence of the Substituents on the Opening of Silylepoxy Alcohols: 5-exo-Cyclization towards Tetrahydrofurans vs. Unexpected Side Reaction Leading to Tetrahydropyrans.

The regioselective ring opening of epoxy alcohols is an effective method for the synthesis of different types of oxacycles. The 5-exo opening being preferred vs. the 6-endo mode, according to Baldwin rules, the use of silyl-substituted oxiranes has been reported as a possible method to favor the 6-endo cyclization. However, there is a need for a detailed study on the different factors (structural factors, catalyst nature or conditions) that influence this process. In this paper, the acid-catalyzed cyclization of epoxysilyl alcohols was studied, focusing on the effect of substituents and reaction conditions on the outcome of the process. Two types of heterocycles (tetrahydrofurans or tetrahydropyrans) were selectively obtained depending on the structure of the initial epoxysilyl alcohol. Interestingly, cyclization of hindered epoxysilyl alcohols mainly proceeds through an unexpected side reaction, which implies a previous isomerization to an aldehyde. A mechanistic proposal for the formation of the different products is presented.

A Guardian Angel Phosphatase for Mainline Carbon Metabolism.

It is increasingly clear that many metabolic enzymes mistakenly form minor but toxic side-products that must be eliminated to maintain normal fluxes. Collard et al. show that this is true of two iconic glycolytic enzymes, and that a hitherto somewhat mysterious phosphatase rescues central carbon metabolism from their mistakes.

Revisiting NO2 as Protecting Group of Arginine in Solid-Phase Peptide Synthesis.

The protection of side-chain arginine in solid-phase peptide synthesis requires attention since current protecting groups have several drawbacks. Herein, the NO2 group, which is scarcely used, has been revisited. This work shows that it prevents the formation of δ-lactam, the most severe side-reaction during the incorporation of Arg. Moreover, it is stable in solution for long periods and can be removed in an easy-to-understand manner. Thus, this protecting group can be removed while the protected peptide is still anchored to the resin, with SnCl2 as reducing agent in mild acid conditions using 2-MeTHF as solvent at 55 °C. Furthermore, we demonstrate that sonochemistry can facilitate the removal of NO2 from multiple Arg-containing peptides.

The Stabilization Effect of CO2 in Lithium-Oxygen/CO2 Batteries.

The lithium (Li)-air battery has an ultrahigh theoretical specific energy, however, even in pure oxygen (O2 ), the vulnerability of conventional organic electrolytes and carbon cathodes towards reaction intermediates, especially O2 - , and corrosive oxidation and crack/pulverization of Li metal anode lead to poor cycling stability of the Li-air battery. Even worse, the water and/or CO2 in air bring parasitic reactions and safety issues. Therefore, applying such systems in open-air environment is challenging. Herein, contrary to previous assertions, we have found that CO2 can improve the stability of both anode and electrolyte, and a high-performance rechargeable Li-O2 /CO2 battery is developed. The CO2 not only facilitates the in situ formation of a passivated protective Li2 CO3 film on the Li anode, but also restrains side reactions involving electrolyte and cathode by capturing O2 - . Moreover, the Pd/CNT catalyst in the cathode can extend the battery lifespan by effectively tuning the product morphology and catalyzing the decomposition of Li2 CO3 . The Li-O2 /CO2 battery achieves a full discharge capacity of 6628 mAh g-1 and a long life of 715 cycles, which is even better than those of pure Li-O2 batteries.

Non-enzymatic molecular damage as a prototypic driver of aging.

The chemical potentialities of metabolites far exceed metabolic requirements. The required potentialities are realized mostly through enzymatic catalysis. The rest are realized spontaneously through organic reactions that (i) occur wherever appropriate reactants come together, (ii) are so typical that many have proper names (e.g. Michael addition, Amadori rearrangement, and Pictet-Spengler reaction), and (iii) often have damaging consequences. There are many more causes of non-enzymatic damage to metabolites than reactive oxygen species and free radical processes (the "usual suspects"). Endogenous damage accumulation in non-renewable macromolecules and spontaneously polymerized material is sufficient to account for aging and differentiates aging from wear-and-tear of inanimate objects by deriving it from metabolism, the essential attribute of life.

Novel side reaction accompanying cyclization of Glu(R1)-Glu(R2) dipeptides via lactamization of the Glu(R1) residue.

A series of linear peptides with the general formula H-Glu(R1)-Glu(R2)-OH was subjected to cyclization under standard conditions. Formation of respective 2,5-diketopiperazines was accompanied by transformation of the N-terminal Glu(R1) to pyroglutamic acid residue. Even in the case R1 is an amino acid residue attached to the N-terminal γ-carboxyl group, lactamization leads to its elimination. The observed reaction has not been reported so far in the literature. Correspondingly, an alternative route to Glu(R1)-Glu(R2)-containing 2,5-diketopiperazines was applied to improve the overall yields.

Metabolite damage and repair in metabolic engineering design.

The necessarily sharp focus of metabolic engineering and metabolic synthetic biology on pathways and their fluxes has tended to divert attention from the damaging enzymatic and chemical side-reactions that pathway metabolites can undergo. Although historically overlooked and underappreciated, such metabolite damage reactions are now known to occur throughout metabolism and to generate (formerly enigmatic) peaks detected in metabolomics datasets. It is also now known that metabolite damage is often countered by dedicated repair enzymes that undo or prevent it. Metabolite damage and repair are highly relevant to engineered pathway design: metabolite damage reactions can reduce flux rates and product yields, and repair enzymes can provide robust, host-independent solutions. Herein, after introducing the core principles of metabolite damage and repair, we use case histories to document how damage and repair processes affect efficient operation of engineered pathways - particularly those that are heterologous, non-natural, or cell-free. We then review how metabolite damage reactions can be predicted, how repair reactions can be prospected, and how metabolite damage and repair can be built into genome-scale metabolic models. Lastly, we propose a versatile 'plug and play' set of well-characterized metabolite repair enzymes to solve metabolite damage problems known or likely to occur in metabolic engineering and synthetic biology projects.

Evaluation of three adjuvants with respect to both adverse effects and the efficacy of antibody production to the Bm86 protein.

Cattle tick infestations remain an important burden for farmers in tropical area like in New Caledonia. With the development of acaricide resistance, tick vaccines should be an attractive alternative to control ticks but their efficacy needs to be improved. In this study three adjuvants were studied in an experimental tick vaccine with a Bm86 protein to assess their performance in terms of antibody productions and adverse reactions following vaccinations. The water-in-oil adjuvant ISA 61 VG led to higher antibody titers compared to a water-in-oil-in-water adjuvant ISA 201 VG and an aqueous polymeric adjuvant Montanide Gel 01. Vaccinations with these three adjuvants did not produce severe general reaction but an increase in skin thickness was observed especially with both oil-based emulsions. These results indicated that the water-in-oil adjuvant is the most interesting to use for this vaccine but local adverse reactions remain an issue.

'Nothing of chemistry disappears in biology': the Top 30 damage-prone endogenous metabolites.

Many common metabolites are intrinsically unstable and reactive, and hence prone to chemical (i.e. non-enzymatic) damage in vivo Although this fact is widely recognized, the purely chemical side-reactions of metabolic intermediates can be surprisingly hard to track down in the literature and are often treated in an unprioritized case-by-case way. Moreover, spontaneous chemical side-reactions tend to be overshadowed today by side-reactions mediated by promiscuous ('sloppy') enzymes even though chemical damage to metabolites may be even more prevalent than damage from enzyme sloppiness, has similar outcomes, and is held in check by similar biochemical repair or pre-emption mechanisms. To address these limitations and imbalances, here we draw together and systematically integrate information from the (bio)chemical literature, from cheminformatics, and from genome-scale metabolic models to objectively define a 'Top 30' list of damage-prone metabolites. A foundational part of this process was to derive general reaction rules for the damage chemistries involved. The criteria for a 'Top 30' metabolite included predicted chemical reactivity, essentiality, and occurrence in diverse organisms. We also explain how the damage chemistry reaction rules ('operators') are implemented in the Chemical-Damage-MINE (CD-MINE) database (minedatabase.mcs.anl.gov/#/top30) to provide a predictive tool for many additional potential metabolite damage products. Lastly, we illustrate how defining a 'Top 30' list can drive genomics-enabled discovery of the enzymes of previously unrecognized damage-control systems, and how applying chemical damage reaction rules can help identify previously unknown peaks in metabolomics profiles.