Overview of emerging catalytic materials for electrochemical green ammonia synthesis and process

The concept of“green-ammonia-zero-carbon emission”is an emerging research topic in the global community and many countries driving toward decarbonizing a diversity of applications dependent on fossil fuels.In light of this,electrochemical nitrogen reduction reaction(ENRR)received great attention at ambient conditions.The low efficiency(%)and ammonia(NH_(3))production rates are two major challenges in making a sustainable future.Besides,hydrogen evolution reaction is another crucial factor for realizing this NH_(3)synthesis to meet the large-scale commercial demand.Herein,the(i)importance of NH_(3)as an energy carrier for the next future,(ii)discussion with ENRR theory and the fundamental mechanism,(iii)device configuration and types of electrolytic systems for NH_(3)synthesis including key metrics,(iv)then moving into rising electrocatalysts for ENRR such as single-atom catalysts(SACs),MXenes,and metal–organic frameworks that were scientifically summarized,and(v)finally,the current technical contests and future perceptions are discussed.Hence,this review aims to give insightful direction and a fresh motivation toward ENRR and the development of advanced electrocatalysts in terms of cost,efficiency,and technologically large scale for the synthesis of green NH_(3).

Bioresorbable magnesium-based alloys containing strontium doped nanohydroxyapatite promotes bone healing in critical sized bone defect in rat femur shaft

Magnesium-based biomaterials have been in extensive research for orthopedic applications for decades due to their optimal mechanical features and osteopromotive nature;nevertheless,rapid degradation restricts their clinical applicability.In this study,pristine magnesium was purified(P-Mg)using a melt self-purification approach and reinforced using indigenously synthesized nanohydroxyapatite(HAP,0.6 wt.%)and strontium substituted nanohydroxyapatite(SrHAP,0.6 wt.%)using a low-cost stir assisted squeeze casting method to control their degradation rate.Using electron back-scattered diffraction(EBSD)and X-ray diffraction(XRD)examinations,all casted materials were carefully evaluated for microstructure and phase analysis.Mechanical characteristics,in vitro degradation,and in vitro biocompatibility with murine pre-osteoblasts were also tested on the fabricated alloys.For in vivo examination of bone formation,osteointegration,and degradation rate,the magnesium-based alloys were fabricated as small cylindrical pins with a diameter of 2.7 mm and a height of 2 mm.The pins were implanted in a critical-sized defect in a rat femur shaft(2.7 mm diameter and 2 mm depth)for 8 weeks and evaluated by microCT and histological evaluation for bone growth and osteointegration.When compared to P-Mg and P-MgHAP,micro-CT and histological analyses revealed that the P-MgSrHAP group had the highest bone formation towards the periphery of the implant and hence maximum osteointegration.When the removed pins from the bone defect were analyzed using GIXRD,they displayed hydroxyapatite peaks that were consistent with bio-integration.For P-Mg,P-MgHAP,and P-MgSrHAP 8 weeks after implantation,in vivo degradation rates derived from micro-CT were around 0.6 mm/year,0.5 mm/year,and 0.1 mm/year,respectively.Finally,P-MgSrHAP possesses the requisite degradation rate as well as sufficient mechanical and biological properties,indicating that it has the potential to be used in the development/fabrication of biodegradable bioactive orthopaedic implants.

PRODUCTION AND CHARACTERIZATION OF POLY(3-HYDROXYBUTYRATE-co-3-HYDROXYHEXANOATE)-POLY(ETHYLENE GLYCOL) HYBIRD COPOLYMER WITH ADJUSTABLE MOLECULAR WEIGHT

A novel natural-synthetic hybrid block copolymer was synthesized by Aeromonas hydrophila 4AK4 in poly（ethylene glycol）（PEG,M_n=200） modified fermentation.This hybrid biomaterial consists of the natural hydrophobic polymer poly（3-hydroxybutyrat-co-3-hydroxyhexanoate）（PHBHHx） end-capped with hydrophilic PEG,which has the increased flexibility as well as the improved thermal stability.Addition of diethylene glycol（DEG） and ethylene glycol could not result in the accumulation of hybrid block copolymer.DEG and ethylene glycol,together with PEG-200,could cause a reduction of molar mass of PHBHHx,resulting in a series of low molecular weight polymer and the reduction of the polymer yield as well as the cellular productivity.In vitro degradation of PHBHHx and PHBHHx-PEG with different molecular weight showed that the decrease of molecular weight accelerated the degradation of copolymers,but PEG modification has little effect on its degradation rate.The results in this study provided a convenient and direct method to produce a series of PHBHHx and PHBHHx-PEG materials with adjustable molecular weight and broad molecular weight distribution which will be very useful for the biomedical applications.

Reserpine Improves Working Memory

Despite exhaustive search, no drug is in sight for AD. Earlier, we reported that reserpine, an antihypertensive and antipsychotic drug, ameliorates Amyloid beta (Aβ-AD causing peptide) toxicity and confers several positive enhancements in the C. elegans model system. Here, we evaluate whether reserpine can provide protection against working memory and against AD in the mouse model. Reserpine (0.08 mg) was administered orally on alternate days to the non-Tg and accelerated Aβ deposition (at 2 months of age)and cognitive deficit (4 months of age) developing 5XFAD AD Tg mouse model expressing mutant human APP (3 familial mutations) and human Presenilin1(2 familial mutations) in the neurons, and follow their working memory for 2 months using the spontaneous Y-maze alteration behavioral paradigm. Reserpine enhanced working memory in non-Tg mice and improved the cognitive deficit in the 5XFAD AD Tg mice. Hence, reserpine can be considered for a detailed evaluation in the 3X Tg AD mouse model and a pilot study in AD patients.

Transplantation of engineered exosomes derived from bone marrow mesenchymal stromal cells ameliorate diabetic peripheral neuropathy under electrical stimulation

Diabetic peripheral neuropathy(DPN)is a long-term complication associated with nerve dysfunction and uncontrolled hyperglycemia.In spite of new drug discoveries,development of effective therapy is much needed to cure DPN.Here,we have developed a combinatorial approach to provide biochemical and electrical cues,considered to be important for nerve regeneration.Exosomes derived from bone marrow mesenchymal stromal cells(BMSCs)were fused with polypyrrole nanoparticles(PpyNps)containing liposomes to deliver both the cues in a single delivery vehicle.We developed DPN rat model and injected intramuscularly the fused exosomal system to understand its long-term therapeutic effect.We found that the fused system along with electrical stimulation normalized the nerve conduction velocity(57.60±0.45 m/s)and compound muscle action potential(16.96±0.73 mV)similar to healthy control(58.53±1.10 m/s;18.19±1.45 mV).Gastrocnemius muscle morphology,muscle mass,and integrity were recovered after treatment.Interestingly,we also observed paracrine effect of delivered exosomes in controlling hyperglycemia and loss in body weight and also showed attenuation of damage to the tissues such as the pancreas,kidney,and liver.This work provides a promising effective treatment and also contribute cutting edge therapeutic approach for the treatment of DPN.

MARIS plays important roles in Arabidopsis pollen tube and root hair growth

In flowering plants, male gametes are delivered to female gametes for double fertilization through pollen tubes. Therefore, pollen tube growth is crucial for double fertilization. Despite its importance to sexual reproduction, genetic mechanisms of pollen tube growth remain poorly understood. In this study, we characterized the receptor-like cytoplasmic protein kinase （RLCK） gene, MARLS （MRI） that plays critical roles in pollen tube growth. MRI is preferentially expressed in pollen grains, pollen tubes and roots. Mutation in MRI by a Ds insertion led to a burst of pollen tubes after pollen germination. Pollen-rescue assay by pollen and pollen tubespecific expression of MRI in the mri-4 mutant showed that loss of MRI function also severely affected root hair elongation. MRI protein interacted with the protein kinase OXIDATIVE SIGNAL INDUCIBLEI （OXII） in the in vitro and in vivo assays, which functions in plant defence and root hair development, and was phosphorylated by OXII in vitro. Our results suggest that MRI plays important roles in pollen tube growth and may function in root hair elongation through interaction with OXII.

High energy superstable hybrid capacitor with a self-regulated Zn/electrolyte interface and 3D graphene-like carbon cathode

Rechargeable aqueous zinc ion hybrid capacitors(ZIHCs),as an up-and-comer aqueous electrochemical energy storage system,endure in their infancy because of the substandard reversibility of Zn anodes,structural deterioration of cathode materials,and narrow electrochemical stability window.Herein,a scalable approach is described that addresses Zn-anode/electrolyte interface and cathode materials associated deficiencies and boosts the electrochemical properties of ZIHCs.The Zn-anode/electrolyte interface is self-regulated by alteration of the traditional Zn2+electrolyte with Na-based supporting salt without surrendering the cost,safety,and green features of the Zn-based system which further validates the excellent reversibility over 1100 h with suppressed hydrogen evolution.The deficits of cathode materials were overcome by using a high-mass loaded,oxygen-rich,3D,multiscaled graphene-like carbon(3D MGC)cathode.Due to the multiscaled texture,high electronic conductivity,and oxygen-rich functional groups of 3D MGC,reversible redox capacitance was obtained with a traditional adsorption/desorption mechanism.Prototype ZIHCs containing the modified electrolyte and an oxygen-rich 3D MGC cathode resulted in battery-like specific energy(203 Wh kg1 at 1.6 A g^(-1))and supercapacitor-type power capability(4.9 kW kg1 at 8 A g^(-1))with outstanding cycling durability(96.75%retention over 30000 cycles at 10 A g^(-1)).These findings pave the way toward the utilization of highly efficient ZIHCs for practical applications.