Oxide Precursor Research Articles

A mixed-ligand strategy for size-controlled synthesis of hydrophobic ZnO nanocrystals by microfluidic reactor

The intrinsic hydrophilicity of ZnO nanocrystals (NCs) leads to their incompatibility with organic media. Current methods for hydrophobization of ZnO NCs involve complex processes, which hinder their mass production and application. In this work, we propose a mixed-ligand strategy for synthesis of size-controlled hydrophobic ZnO NCs by oxidation of organometallic zinc precursor in the presence of amine and trioctylphosphine oxide (TOPO). Growth kinetic study reveals the dual role of TOPO in accelerating the nucleation and inhibiting the growth of ZnO NCs, demonstrating the importance of TOPO dosage to rapid synthesis of ZnO NCs. Other factors governing the growth kinetic are systematically investigated to optimize the synthesis control for wide range of size tunability. Finally, monodispersed hydrophobic ZnO NCs with the size of 2–13 nm are produced through microfluidic reactor, and one “synthesis run” takes 3–30 min. The hydrophobic ZnO NCs exhibit superior photocatalytic performance than the hydrophilic ones in degradation of Sudan dyes, which is attributed to its strong affinity to the dye molecules. We expected the synthesis strategy will promote the development and applications of hydrophobic ZnO NCs in various fields of photocatalysis, sensors, and optoelectronics.

Low-Temperature Fabrication of Bulk-Type All-Solid-State Lithium-Ion Battery Utilizing Nanosized Garnet Solid Electrolytes.

Garnet-type Li7 La3 Zr2 O12 (LLZ) materials are attracting attention as solid electrolytes (SEs) in oxide-based all-solid-state batteries (ASSBs) owing to their high ionic conductivity. Although the electrochemical stability of LLZ against Li metal is demonstrated with possible high energy density, high-temperature sintering above 1000 °C, which is required to achieve high Li-ion conductivity, results in the formation of insulating impurities at the electrode-electrolyte interfaces. Here, nanosized fine-particle samples of Ta-substituted Li6.5 La3 Zr1.5 Ta0.5 O12 (LLZT) are successfully prepared at a remarkably low temperature of 400 °C utilizing an amorphous precursor oxide. The dense LLZT SE sintered by hot pressing at 500 °C shows room-temperature Li-ion conductivity of 1.03 × 10-4 S cm-1 without any additives. In addition, the bulk-type NCM-graphite full battery cell fabricated with the LLZT fine particles through a hot-pressing sintering method at 550 °C exhibits a good charge-discharge performance at room temperature with the bulk-type areal discharge capacity of 0.831 mAh cm-2 . The nanosized garnet SE strategy demonstrated in this study paves the way for the formation of oxide-based ASSBs by low-temperature sintering.

Molten-Salt Electrochemical Deoxidation Synthesis of Platinum-Neodymium Nanoalloy Catalysts for Oxygen Reduction Reaction.

Platinum-rare earth metal (Pt-RE) nanoalloys are regarded as a potential high performance oxygen reduction reaction (ORR) catalyst. However, wet chemical synthesis of the nanoalloys is a crucial challenge because of the extremely high oxygen affinity of RE elements and the significantly different standard reduction potentials between Pt and RE. Here, this paper presents a molten-salt electrochemical synthetic strategy for the compositional-controlled preparation of platinum-neodymium (Pt-Nd) nanoalloy catalysts. Carbon-supported platinum-neodymium (Ptx Nd/C) nanoalloys, with distinct compositions of Pt5 Nd and Pt2 Nd, are obtained through molten-salt electrochemical deoxidation of platinum and neodymium oxide (Pt-Nd2 O3 ) precursors supported on carbon. The Ptx Nd/C nanoalloys, especially the Pt5 Nd/C exhibit a mass activity of 0.40Amg-1 Pt and a specific activity of 1.41mAcm-2 Pt at 0.9V versus RHE, which are 3.1 and 7.1 times higher, respectively, than that of commercial Pt/C catalyst. More significantly, the Pt5 Nd/C catalyst is remarkably stable after undergoing 20000 accelerated durability cycles. Furthermore, the density-functional-theory (DFT) calculations confirm that the ORR catalytic performance of Ptx Nd/C nanoalloys is enhanced by compressive strain effect of Pt overlayer, causing a suitable weakened binding energies of O* and .

Bottom-up synthesis of carbon materials with an exceptionally high percentage of pentagons or tertiary nitrogen by brominating precursors

Carbon materials with pentagons and graphitic nitrogen (tertiary nitrogen) have attracted much attention due to their prominent electrical and chemical properties. However, the low percentage of introduced pentagons and tertiary nitrogen as well as residual hydrogen originating from precursors have been problems. In this study, three precursors such as corannulene (Cora), indolizine (ID), and indolizino [6,5,4,3-ija]quinoline (IQ) were brominated by two different reaction methods such as heat treatment and ultrasonic treatment for preparing carbon materials with high percentages of pentagons and tertiary nitrogen. Unlike general bromination by heat treatment, ultrasonic bromination avoided the oxidation of precursors, leading to more controlled structures of carbon materials. A carbon material with exceptionally high percentages of retained pentagons (96%) and reacted edges (50%) as well as another carbon material with exceptionally high percentages of tertiary nitrogen (93%) and reacted edges (74%) were successfully synthesized by carbonizing the brominated Cora at 773 K and the brominated IQ at 873 K, respectively. Compared to non-brominated precursors such as Cora and IQ, bromination of precursors lowered the carbonization temperature and increased the percentage of reacted edges, while maintaining a high percentage of pentagons and that of tertiary nitrogen, respectively.

Seasonal variation characteristics of atmospheric peroxyacetyl nitrate (PAN) and its source apportionment in a megacity in southern China

Owing to its biotoxicity and inductive effect on photochemical pollution, atmospheric peroxyacetyl nitrate (PAN), which is a typical product of atmospheric photochemical reactions, has attracted much research attention. However, to the best of our knowledge, few comprehensive studies have been conducted on the seasonal variation and key influencing factors of PAN concentrations in southern China. In this study, PAN, ozone (O3), precursor volatile organic compound (VOC), and other pollutant concentrations were measured online for 1 year (from October 2021 to September 2022) in Shenzhen, a megacity in the Greater Bay Area of China. The average concentrations of PAN and peroxypropionyl nitrate (PPN) were 0.54 and 0.08 parts per billion (ppb), and the maximum hourly concentrations reached 10.32 and 1.01 ppb, respectively. The results of the generalized additive model (GAM) showed that the atmospheric oxidation capacity and precursor concentration were the most important factors affecting the PAN concentration. According to the steady-state model, the average cumulative contribution to the peroxyacetyl (PA) radical formation rate by six major carbonyl compounds was calculated at 4.2 × 106 molecules cm−3 s−1, and acetaldehyde (63.0 %) and acetone (13.9 %) contributed the most. Furthermore, the photochemical-age-based parameterization method was used to analyze the source contributions of carbonyl compounds and PA radicals. The results showed that although the primary anthropogenic (40.2 %), biogenic (27.8 %), and secondary anthropogenic (16.4 %) sources were the most important contributors of PA radicals, the biogenic and secondary anthropogenic source contributions both increased considerably in summer, and the cumulative proportion of both sources reached ~70 % in July. In addition, a comparison of PAN pollution processes in different seasons revealed that in summer and winter, the PAN concentration was predominantly limited by precursors and meteorological parameters, such as light intensity, respectively.

Rapid and controllable synthesis of LiCoO2 cathode materials by reactive flash sintering

AbstractLiCoO2 (LCO) has been widely adopted as the electrode for lithium‐ion batteries (LIBs) which provide a solution for settling problems referring to energy and environment. The demand for rapid and controllable synthesis of LCO increases dramatically. In this work, reactive flash sintering (RFS), for the first time, was introduced to synthesize LCO rapidly and controllably based on simple oxide precursors. The as‐prepared LCO, investigated by physicochemical property characterization, showed well‐constructed and high crystallinity and controllable morphologies, in which the grain size varied with the magnitude of the applied limited current value, allowing for grain size modulation. Furthermore, the as‐prepared LCO exhibited excellent performance in cyclic stability and rate capacity by contrast with that synthesized by the conventional solid‐phase sintering method. This is admittedly attributed to better crystallinity and less lithium loss. Therefore, RFS provides a new approach for the manufacture of LCO electrode and has the potential to be applied to other electrode materials for LIBs.

Universal Strategy for Reversing Aging and Defects in Graphene Oxide for Highly Conductive Graphene Aerogels.

The production of highly stable, defect-free, and electrically conducting 3D graphene structures from graphene oxide precursors is challenging. This is because graphene oxide is a metastable material whose structure and chemistry evolve due to aging. Aging changes the relative composition of oxygen functional groups attached to the graphene oxide and negatively impacts the fabrication and properties of reduced graphene oxide. Here, we report a universal strategy to reverse the aging of graphene oxide precursors using oxygen plasma treatment. This treatment decreases the size of graphene oxide flakes and restores negative zeta potential and suspension stability in water, enabling the fabrication of compact and mechanically stable graphene aerogels using hydrothermal synthesis. Moreover, we employ high-temperature annealing to remove oxygen-containing functionalities and repair the lattice defects in reduced graphene oxide. This method allows obtaining highly electrically conducting graphene aerogels with electrical conductivity of 390 S/m and low defect density. The role of carboxyl, hydroxyl, epoxide, and ketonic oxygen species is thoroughly investigated using X-ray photoelectron and Raman spectroscopies. Our study provides unique insight into the chemical transformations occurring during the aging and thermal reduction of graphene oxide from room temperature up to 2700 °C.

Interfacial Molecular Compatibility for Programming Organic-Metal Oxide Superlattices.

Artificially programming a sequence of organic-metal oxide multilayers (superlattices) by using atomic layer deposition (ALD) is a fascinating and challenging issue in material chemistry. However, the complex chemical reactions between ALD precursors and organic layer surfaces have limited their applications for various material combinations. Here, we demonstrate the impact of interfacial molecular compatibility on the formation of organic-metal oxide superlattices using ALD. The effects of both organic and inorganic compositions on the metal oxide layer formation processes onto self-assembled monolayers (SAM) were examined by using scanning transmission electron microscopy, in situ quartz crystal microbalance measurements, and Fourier-transformed infrared spectroscopy. These series of experiments reveal that the terminal group of organic SAM molecules must satisfy two conflicting requirements, the first of which is to promptly react with ALD precursors and the second is not to bind strongly to the bottom metal oxide layers to avoid undesired SAM conformations. OH-terminated phosphate aliphatic molecules, which we have synthesized, were identified as one of the best candidates for such a purpose. Molecular compatibility between metal oxide precursors and the -OHs must be properly considered to form superlattices. In addition, it is also important to form densely packed and all-trans-like SAMs to maximize the surface density of reactive -OHs on the SAMs. Based on these design strategies for organic-metal oxide superlattices, we have successfully fabricated various superlattices composed of metal oxides (Al-, Hf-, Mg-, Sn-, Ti-, and Zr oxides) and their multilayered structures.

Large simulated future changes in the nitrate radical under the CMIP6 SSP scenarios: implications for oxidation chemistry

Abstract. The nitrate radical (NO3) plays an important role in the chemistry of the lower troposphere, acting as the principle oxidant during the night together with ozone. Previous model simulations suggest that the levels of NO3 have increased dramatically since the preindustrial period. Here, we show projections of the evolution of the NO3 radical from 1850–2100 using the United Kingdom Earth System Model (UKESM1) under the Coupled Model Intercomparison Project Phase 6 (CMIP6) shared socioeconomic pathway (SSP) scenarios. Our model results highlight diverse trajectories for NO3, with some scenarios and regions undergoing rapid growth of NO3 to unprecedented levels over the course of the 21st century and others seeing sharp declines. The local increases in NO3 (up to 40 ppt above the preindustrial base line) are driven not only by local changes in emissions of nitrogen oxides but have an important climate component, with NO3 being favoured in warmer future climates. The changes in NO3 lead to changes in the oxidation of important secondary organic aerosol precursors, with potential impacts on particulate matter pollution regionally and globally. This work highlights the potential for substantial future growth in NO3 and the need to better understand the formation of secondary organic aerosol (SOA) from NO3 to accurately predict future air quality and climate implications.

(130) Increasing Penile Length and Girth in Healthy Men Using a Novel Protocol: The P-Long Study

Abstract Introduction Various therapies have been utilized to increase penile length and girth, with some exhibiting significant adverse event profiles, including fillers, fat transfers, suspensory ligament ligation, and silicon augmentation. Our team sought to evaluate a novel combination therapy to enhance penile characteristics using platelet-rich plasma (PRP) as a source of autologous growth factors, penile traction for lengthening, a vacuum erection device for girth enhancement, and nitric oxide precursor supplements to augment penile vascular smooth muscle function. Objective To evaluate the safety and efficacy of combination therapy with PRP, traction, vacuum device, and nitric oxide boosting nutritional supplements to increase penile length, girth, and function in healthy men. Methods A prospective, non-randomized study was designed (NCT04231422) to evaluate the efficacy of combination therapy in healthy men aged 20-55 with baseline normal erectile function and no penile pathology. Penile length and girth measurements were obtained using at-home photography of an erect penis with maximal tumescence. Measurements were obtained at baseline and at monthly intervals x 6 months. PRP (a modified P-Shot ® Procedure) was administered in the right and left corpora under ultrasound guidance once a month for six months using PureSpin double spin system (60cc blood drawn). Centrifuge technical data show an average platelet recovery of 84% and an average concentration of 6.6 times that of the whole blood sample. Using this data, the injection of 10cc of PRP, assuming a starting platelet count of 250K/microliter, would contain approximately 1.65 billion platelets. Subjective erectile function was assessed with a 5 point Likert Scale. RestoreX traction device was utilized for 20 minutes, twice daily, and a Dr Joel Kaplan vacuum erection device was applied with 5-10 mmHg pressure x 12 minutes (1 min x 2, 5 min x 2). Oral nitric oxide boosting supplementation was with AFFIRM, consisting of 3 gm L-Citrulline and 1 gm beet extract. Results A total of 32 men have been enrolled, with 16 having complete data available for review. The 6-month mean increase in the size of the erect penis was 0.85 inches in length (95% CI: 0.75 to 0.94, p-value < 0.01) (range 0.5-1.44) with a linear increase in size. The 6-month mean increase in circumference was 0.47 inches (95% CI: 0.37 to 0.57, p-value <0.01) (range 0.2-0.75). Mean age was 32 and mean baseline erect penile length was 5.70 and girth was 5.25. All 16 participants reported better penile rigidity with erections. No adverse events were reported. Conclusions Results from a pilot study using a novel combination therapy (P-Long Protocol) in healthy men demonstrated increases in penile length, girth, and subjective rigidity improvement compared to baseline with no adverse effects. External validation is warranted. The P-Long Protocol does not require any synthetic injectables or foreign bodies. It does not preclude additional augmentation procedures. The slope of the growth curve indicates possible continued growth with additional treatments. Disclosure Any of the authors act as a consultant, employee or shareholder of an industry for: BTL Inc.

Microwave-assisted chemical synthesis of SmCo5 magnetic particles with high coercivity

The hard-magnetic SmCo5-based materials with high coercivity have an enormous range of high-value-added technological applications. We reported the novel synthesis of SmCo5 particles with desired particle size by a microwave-assisted combustion process. The process consists of a combination of Sm-Co oxide precursor preparation by microwave-assisted combustion, and the following calcium hydride reduction-diffusion. The microwave-assisted combustion offers a time and energy-saving, and environmentally-friendly methodology to form the homogenous Sm-Co oxide precursor nanoparticles. This high-quality Sm-Co oxide precursor paves the way for achieving high coercivity in SmCo5 magnetic materials. A high coercivity up to 39.2 kOe was achieved in the aligned SmCo5 particles. These SmCo5 magnetic particles show promising prospects for high-performance permanent magnet applications and can be utilized for the development of exchange-coupled nanocomposite magnets with high energy density. This work also provides instructive information for designing and synthesizing rare-earth-based magnetic materials.

PFAS in municipal landfill leachate: Occurrence, transformation, and sources

To understand sources and processes affecting per- and polyfluoroalkyl substances (PFAS), 32 PFAS were measured in landfill leachate from 17 landfills across Washington State in both pre-and post-total oxidizable precursor (TOP) assay samples, using an analytical method that was the precursor to EPA Draft Method 1633. As in other studies, 5:3FTCA was the dominant PFAS in the leachate, suggesting that carpets, textiles, and food packaging were the main sources of PFAS. Total PFAS concentrations (Σ32PFAS) ranged from 61 to 172,976 ng/L and 580–36,122 ng/L in pre-TOP and post-TOP samples, respectively, suggesting that little or no uncharacterized precursors remained in landfill leachate. Furthermore, due to chain-shortening reactions, the TOP assay often resulted in a loss of overall PFAS mass. Positive matrix factorization (PMF) analysis of the combined pre- and post-TOP samples produced five factors that represent sources and processes. Factor 1 consisted primarily of 5:3FTCA (intermediate of 6:2 fluorotelomer degradation and characteristic of landfill leachate), while factor 2 was dominated by PFBS (degradant of C-4 sulfonamide chemistry) and, to a lesser extent, by several PFCAs and 5:3FTCA. Factor 3 consisted primarily of both short-chain PFCAs (end-products of 6:2 fluorotelomer degradation) and PFHxS (derived from C-6 sulfonamide chemistry), while the main component of factor 4 was PFOS (dominant in many environmental media but minor in landfill leachate, perhaps reflecting a production shift from longer to shorter chain PFAS). Factor 5, highly loaded with PFCAs, was dominant in post-TOP samples and therefore represented the oxidation of precursors. Overall, PMF analysis suggests that the TOP assay approximates some redox processes which occur in landfills, including chain-shortening reactions which yield biodegradable products.

Design and characterization of spinnable carboxylate-based La–Zr oxide precursor towards scalable preparation of micro/nano lanthanum zirconate fibers for thermal management

Rare earth zirconates have incomparable chemical thermophysical properties, yet the difficulty of preparation methods limit their application as fibrous material. In present work, a spinnable La2Zr2O7 precursor, named as carboxylate lanthanum-zirconium (COLZ), was developed using carboxylic acids as structural and functional ligands. When COLZ is in its liquid state, it can be readily processed into desired shapes, allowing preparation of high aspect ratio precursor fibers with dense and bonding-strong internal structures. The spinnability was explained by the transformation from solid to liquid state under external forces, in which dynamic bridging of carboxylate and hydroxyl between nano-sized colloidal particles play a key role. Due to weakly acidic ligands, organics in COLZ can be easily removed, making direct heat treatment at the target temperature possible, which is beneficial for massive production. The strategy of developing spinnable precursor could also be applied to prepare other rare earth zirconate fibers or new multi-oxide fibers.

Uranium(IV) and Thorium(IV) Coordination Polymers Based on Tritopic Carboxylic Acids.

Nine new coordination polymers based on U(IV) and Th(IV) were synthesized solvothermally utilizing four different trianionic carboxylates (H3BHTC = biphenyl-3,4',5-tricarboxylic acid, H3NTB = 4,4',4″-nitrilotribenzoic acid, H3BTB = 4,4',4″-benzene-1,3,5-triyl-tris(benzoic acid), H3BTE = 4,4',4″-(1,3,5-benzenetriyltri-2,1-ethynediyl)trisbenzoic acid). The influence of the ligand architecture, the pH, the stoichiometry, the nature of the metal, and the concentration on the structure and dimensionality of the final actinide assembly is discussed. The H3BHTC ligand allowed the synthesis of a cationic three-dimensional (3D) framework [U(BHTC)(DMF)3]I (1), which is the first example of a cationic U(IV) polymer. The H3NTB ligand yielded the 3D neutral polymer [U3(NTB)4] (2) or the two-dimensional (2D) cationic polymer [U(NTB)(NMP)3]I (3), depending on the solvent. When conditions leading to (2) were used with a Th(IV) precursor, the 2D neutral polymer [Th(NTB)(DMF)3Cl] (4) was obtained. The ligand H3BTB allowed the synthesis of two 3D cationic networks [U(BTB)(DMF)2]I (5) and [U(BTB)(DMF)3]I (7) or the neutral 3D analogue [U3(BTB)4] (6), depending on the precursor's oxidation state and the acidity of the reaction mixture. The ligand H3BTE allowed the synthesis of the anionic 3D [(CH3)2NH2][U2(BTE)3] (8) framework featuring large accessible pores, and under the same conditions, an isostructural Th(IV) was also obtained [(CH3)2NH2][Th2(BTE)3] (8-Th). All isolated coordination polymers were characterized by single-crystal X-ray diffraction (SCXRD). The Langmuir surface areas of the U(IV) polymers (2), (7), and (8) increased from 140 to 310 m2/g owing to the increasing size of the linker, with polymer (8) showing a value that is comparable to the highest surface area reported to date. The effect of the postsynthetic solvent substitution was also studied, revealing a crystal-to-crystal transformation of the cationic framework (7) to the neutral framework [U(BTB)(THF)I] (7c).

A new (La0.2Nd0.2Gd0.2Sr0.2Ba0.2)Co0.2Fe0.8O3-δ high-entropy oxide cathode for intermediate temperature solid oxide fuel cell

The main degradation mechanism of La0.6Sr0.4Co0.2Fe0.8O3-δ cathodes is Sr segregation on the surface. In this paper, the high-entropy (La0.2Nd0.2Gd0.2Sr0.2Ba0.2)Co0.2Fe0.8O3-δ(HE-LSCF) oxide with perovskite-type is designed to improve the cathode stability. The orthorhombic perovskite phase with the space group of Pbnm(62) is obtained when the HE-LSCF oxide precursor powders are calcined at 800 °C for 2 h. The orthorhombic perovskite phase is still stable when the HE-LSCF oxide precursor powders are calcined at 1250 °C for 2 h. At 700 °C，the specific polarization resistance (Rasp) of the pristine HE-LSCF and La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathodes is 0.71Ωcm2 and 0.57Ωcm2, respectively. The electrode process related to the oxygen dissociation and the interfacial charge transfer involving atomic oxygen is the rate-determining step of the oxygen reduction reaction in HE-LSCF cathodes. After being aged for 200 h at 800 °C, Rasp at 700 °C of the LSCF and HE-LSCF electrodes increases by 122.8% and 5.6%，respectively. The SEM, EDS and XPS results show that Sr segregates on the LSCF cathode surface after being aged, but Sr segregation on the HE-LSCF cathode surface is hindered. The research results show that HE- LSCF will be a potential cathode material for the intermediate temperature solid oxide fuel cells.

Potential of the Biomass Waste Originating from Saccharum officinarum as a Fenton Precursor for the Efficient Oxidation of Azo Dye from an Aqueous Stream

In the current investigation, elements extracted from Saccharum officinarum were identified as exporters of Fenton catalysts. Saccharum officinarum was soaked in an alkali prior to acidic treatment and then subjected to pyrolysis for elemental recovery. X-ray diffraction (XRD) and scanning electron microscopy (SEM) augmented with energy-dispersive X-ray spectroscopy (EDX) were used to identify the prepared catalyst. The material was combined with hydrogen peroxide, which led to Fenton’s reaction. Then, the modified Fenton system was applied to eliminate the textile dye, named Bismarck Brown Azo dye, contaminating the aqueous effluent. Response surface methodological model (RSM) analysis was used to identify the most effective operational parameters, and the model set the optimized values as 39 and 401 mg/L for Saccharum officinarum and H2O2 doses, respectively, at pH 2.9. The maximum Bismarck Brown Azo dye removal achieved was 85%. Increasing the temperature to 60 °C improved the dye oxidation efficiency. However, the dye treatment efficacy was reduced when the dye loading increased. Additionally, the kinetic rate order was investigated and the system was fitted to second-order rate reaction kinetics. The thermodynamic variables show that the reaction is endothermic and non-spontaneous.

Effect of ultrasonic irradiation on the production of a dihydrate precursor for selective n-butane oxidation

The invention pertains to a method for synthesising vanadium phosphorus oxide (VPO) catalyst using an ultrasonic irradiation approach and comparing phase composition and hydrocarbon oxidation activity to a traditionally synthesised catalyst. The ultrasonic irradiation method has been identified to create a catalyst with superior surface constitution and enhanced hydrocarbon conversionin a much shorter time of 3 h than the traditional heating method, which takes 24 h. The nature of catalyst influences product selectivity, with an integration comprising (VO)2P2O7 (V4+) and VOPO4 (V5+) being optimum for high rate of conversion. Under ideal reaction conditions, 89% selectivity to maleic anhydride and a 39% conversion rate were obtained.

Proteolytically Resistant Bioactive Peptide-Grafted Sr/Mg-Doped Hardystonite Foams: Comparison of Two Covalent Functionalization Strategies.

Hardystonite-based (HT) bioceramic foams were easily obtained via thermal treatment of silicone resins and reactive oxide fillers in air. By using a commercial silicone, incorporating strontium oxide and magnesium oxide precursors (as well as CaO and ZnO), and treating it at 1100 °C, a complex solid solution (Ca1.4Sr0.6Zn0.85Mg0.15Si2O7) that has superior biocompatibility and bioactivity properties compared to pure hardystonite (Ca2ZnSi2O7) can be obtained. Proteolytic-resistant adhesive peptide mapped on vitronectin (D2HVP), was selectively grafted to Sr/Mg-doped HT foams using two different strategies. Unfortunately, the first method (via protected peptide) was unsuitable for acid-sensitive materials such as Sr/Mg-doped HT, resulting in the release of cytotoxic levels of Zinc over time, with consequent negative cellular response. To overcome this unexpected result, a novel functionalization strategy requiring aqueous solution and mild conditions was designed. Sr/Mg-doped HT functionalized with this second strategy (via aldehyde peptide) showed a dramatic increase in human osteoblast proliferation at 6 days compared to only silanized or non-functionalized samples. Furthermore, we demonstrated that the functionalization treatment does not induce any cytotoxicity. Functionalized foams enhanced mRNA-specific transcript levels coding IBSP, VTN, RUNX2, and SPP1 at 2 days post-seeding. In conclusion, the second functionalization strategy proved to be appropriate for this specific biomaterial and was effective at enhancing the material's bioactivity.

Stable structure and fast ion diffusion: N-doped VO2 3D porous nanoflowers for applications in ultrafast rechargeable aqueous zinc-ion batteries

Aqueous rechargeable zinc-ion batteries (ARZIBs) are promising candidates for fast-charging energy-storage systems. The issues of stronger interactions between Zn2+ and the cathode for ultrafast ARZIBs can be partially addressed by enhancing mass transfer and ion diffusion of the cathode. Herein, via thermal oxidation for the first time, N-doped VO2 porous nanoflowers with short ion diffusion paths and improved electrical conductivity were synthesized as ARZIBs cathode materials. The introduction of nitrogen derived from the vanadium-based-zeolite imidazolyl framework (V-ZIF) contributes to enhanced electrical conductivity and faster ion diffusion, while the thermal oxidation of the VS2 precursor assists the final product in exhibiting a more stable three-dimensional nanoflower structure. In particular, the N-doped VO2 cathode shows excellent cycle stability and superior rate capability with the delivered capacities of 165.02 mAh g−1 and 85 mAh g−1, at 10 A g−1 and 30 A g−1, and the capacity retention of 91.4% after 2200 cycles and 99% after 9000 cycles, respectively. Remarkably, the battery takes less than 10 s to be fully charged at 30 A g−1. Hence, this work provides a new avenue for designing unique nanostructured vanadium oxides and developing electrode materials suitable for ultrafast charging.

Short-Term L-Citrulline Supplementation Does Not Affect Inspiratory Muscle Oxygenation and Respiratory Performance in Older Adults

In sports nutrition, nitric oxide (NO•) precursors such as L-citrulline are widely used to enhance NO• bioavailability, which is considered an ergogenic aid. Our study aimed to examine the effect of short-term L-citrulline supplementation on respiratory muscles' performance, fatigue, and oxygenation in older adults. Fourteen healthy older males took 6 g of L-citrulline or a placebo for seven days in a double-blind crossover design. Pulmonary function via spirometry (i.e., forced expired volume in 1 s (FEV1), forced vital capacity (FVC), and their ratio)), fractional exhaled nitric oxide (NO•), maximal inspiratory pressure (MIP), rate of perceived exertion, and sternocleidomastoid muscle oxygenation (i.e., oxyhemoglobin (Δ[O2Hb]) and de-oxyhemoglobin (Δ[HHb]), total hemoglobin concentration (Δ[tHb]), and tissue saturation index (TSI%)) were evaluated at baseline, after seven days of L-citrulline supplementation, and after incremental resistive breathing to task failure of the respiratory muscles. The exhaled NO• value was only significantly increased after the supplementation (26% p < 0.001) in the L-citrulline condition. Pulmonary function, MIP, rate of perceived exertion, and sternocleidomastoid muscle oxygenation were not affected by the L-citrulline supplementation. In the present study, although short-term L-citrulline supplementation increased exhaled NO•, no ergogenic aids were found on the examined parameters at rest and after resistive breathing to task failure in older adults.