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Considering the substantial role of ammonia, developing highly efficient electrocatalysts for nitrate-to-ammonia conversion has attracted increasing interest. Herein, we proposed a feasible strategy of p-d orbital hybridization via doping p-block metals in an Ag host, which drastically promotes the performance of nitrate adsorption and disassociation. Typically, a Sn-doped Ag catalyst (SnAg) delivers a maximum Faradaic efficiency (FE) of 95.5±1.85 % for NH3 at -0.4â V vs. RHE and reaches the highest NH3 yield rate to 482.3±14.1â mg h-1 mgcat. -1. In a flow cell, the SnAg catalyst achieves a FE of 90.2 % at an ampere-level current density of 1.1â A cm-2 with an NH3 yield of 78.6â mg h-1 cm-2, during which NH3 can be further extracted to prepare struvite as high-quality fertilizer. A mechanistic study reveals that a strong p-d orbital hybridization effect in SnAg is beneficial for nitrite deoxygenation, a rate-determining step for NH3 synthesis, which as a general principle, can be further extended to Bi- and In-doped Ag catalysts. Moreover, when integrated into a Zn-nitrate battery, such a SnAg cathode contributes to a superior energy density of 639â Wh L-1, high power density of 18.1â mW cm-2, and continuous NH3 production.
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Alkali ions, major components at the electrode-electrolyte interface, are crucial to modulating reaction activity and selectivity of catalyst materials. However, the underlying mechanism of how the alkali ions catalyze the N2 reduction reaction (NRR) into ammonia remains elusive, posing challenges for experimentalists to select appropriate electrolyte solutions. In this work, by employing a combined experimental and computational approach, we proposed four essential roles of cation ions at Fe electrodes for N2 fixation: (i) promoting NN bond cleavage; (ii) stabilizing NRR intermediates; (iii) suppressing the competing hydrogen evolution reaction (HER); and (iv) modulating the interfacial charge distribution at the electrode-electrolyte interface. For N2 adsorption on an Fe electrode with cation ions, our constrained ab initio molecular dynamic (c-AIMD) results demonstrate a barrierless process, while an extra 0.52 eV barrier requires to be overcome to adsorb N2 for the pure Fe-water interface. For the formation of *NNH species within the N2 reduction process, the calculated free energy barrier is 0.50 eV at the Li+-Fe-water interface. However, the calculated barrier reaches 0.81 eV in pure Fe-water interface. Furthermore, experiments demonstrate a high Faradaic efficiency for ammonia synthesis on a Li+-Fe-water interface, reaching 27.93% at a working potential of -0.3 V vs RHE and pH = 6.8. These results emphasize how alkali metal cations and local reaction environments on the electrode surface play crucial roles in influencing the kinetics of interfacial reactions.
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The quest for sustainable urea production has directed attention toward electrocatalytic methods that bypass the energy-intensive traditional Haber-Bosch process. This study introduces an approach to urea synthesis through the coreduction of CO2 and NO3- using copper-doped molybdenum diselenide (Cu-MoSe2) with Cu-Mo dual sites as electrocatalysts. The electrocatalytic activity of the Cu-MoSe2 electrode is characterized by a urea yield rate of 1235 µg h-1 mgcat.-1 at -0.7 V versus the reversible hydrogen electrode and a maximum Faradaic efficiency of 23.43% at -0.6 V versus RHE. Besides, a continuous urea production with an enhanced average yield rate of 9145 µg h-1 mgcat.-1 can be achieved in a flow cell. These figures represent a substantial advancement over that of the baseline MoSe2 electrode. Density functional theory (DFT) calculations elucidate that Cu doping accelerates *NO2 deoxygenation and significantly decreases the energy barriers for C-N bond formation. Consequently, Cu-MoSe2 demonstrates a more favorable pathway for urea production, enhancing both the efficiency and feasibility of the process. This study offers valuable insights into electrode design and understanding of the facilitated electrochemical pathways.
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Objective: Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS) and Laryngopharyngeal Reflux Disease (LPRD) are interrelated medical conditions affecting the respiratory system. This article aimed to investigate the potential correlation between the two. Methods: This cross-sectional study was carried out on a total of 52 participants diagnosed with both OSAHS and LPRD. Clinical data of baseline demographics of year, sex, BMI, including clinical indicators such as AHI (Apnea Hypopnea Index), OSAHS severity grading, RFS (Reflux Finding Score), RSI (Reflux Symptom Index), and 24-hour pH level were collected. Statistical analysis was then conducted to evaluate the correlation between OSAHS and LPRD. Results: Among the 52 patients, the the average age was 43.3±11.6 years with a mean 24.7±2.9 kg/m2 BMI level. The mean duration of OSAHS was 4.1±1.7 years with mean 38.7±12 AHI scores and 30.8% mild OSAHS, 51.9% moderate OSAHS, and 17.3% severe OSAHS. Mean LPRD duration was 3.2±1.5 years with a mean 15.9±4.9 RFS score, mean 28.0±6.8 RSI score, and mean 3.9±0.8 24-hour pH level. There was a strong positive correlation between AHI scores and both the RFS score (r>0.9, P < .01) and RSI score (r>0.9, P < .01). While a strong negative correlation between AHI scores and 24-hour pH level was observed (r < -0.8, P < .01). And there was a strong positive correlation between OSAHS severity levels and both the RSF score (r>0.8, P < .01) and RSI score (r>0.79, P < .01). While a significant negative correlation between OSAHS severity and 24-hour pH level was detected (r < -0.7, P < .01). Conclusions: The findings of this cross-sectional study demonstrate a strong positive correlation between the severity of OSAHS, as indicated by AHI scores, and the severity of LPRD, as measured by RFS and RSI scores. A negative correlation was also observed between AHI scores and 24-hour pH level, indicating a connection between these two medical conditions.
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The effects of HNK, I5, and I6 on the expression of protein in hippocampus of depressed mice were studied by isobaric tags for relative and absolute quantitation (iTRAQ) to explore the mechanism of their antidepressant action. HNK, I5, and I6 were administered intragastric administration once a day in the morning for 7 days. The drug was subsequently discontinued for 7 days (without any treatment). On the 15th day, mice in each group were given the drug (1.0, 10.0, 30.0 mg/kg) intragastric stimulation and mouse hippocampal tissues were taken to perform iTRAQ to identify differentially expressed proteins, and bioinformatics was used to analyze the functional enrichment of the differentially expressed proteins. Compared with Ctr group, the number of differentially expressed proteins in HNK, I5, and I6 treatment groups was 158, 88, and 105, respectively. The three groups shared 29 differentially expressed proteins. In addition, compared with HNK group, the number of differentially expressed proteins in I5 and I6 groups was 201 and 203, respectively. A total of 47 and 56 differentially expressed proteins were co-expressed in I5 and I6 groups. Bioinformatics analysis showed that these differentially expressed proteins mainly had the functions of binding, biocatalysis, and transport, and mainly participated in cellular process, biological regulation process, biological metabolism process, and stress reaction process. GO and KEGG pathway analysis found that these differentially expressed proteins were involved long-term potentiation, G13 pathway, platelet activation pathway, and MAPK signaling pathway. HNK, I5, and I6 antidepressants are closely related to sudden stress sensitivity, stress resistance, neurotransmitter, and metabolic pathways. This study provides a scientific basis to further elucidate the mechanism and clinical application of HNK, I5, and I6 antidepressants.
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Ketamina , Proteômica , Camundongos , Animais , Antidepressivos/farmacologia , Antidepressivos/uso terapêutico , Antidepressivos/metabolismo , Ketamina/farmacologia , Transdução de SinaisRESUMO
Urea synthesis from abundant CO2 and N-feedstocks via renewable electricity has attracted increasing interests, offering a promising alternative to the industrial-applied Haber-Meiser process. However, the studies toward electrochemical urea production remain scarce and appeal for more research. Herein, in this perspective, an up-to-date overview on the urea electrosynthesis is highlighted and summarized. Firstly, the reaction pathways of urea formation through various feedstocks are comprehensively discussed. Then, we focus on the strategies of materials design to improve C-N coupling efficiency by identifying the descriptor and understanding the reaction mechanism. Finally, the current challenges and disadvantages in this field are reviewed and some future development directions of electrocatalytic urea synthesis are also prospected. This Minireview aims to promote future investigations of the electrochemical urea synthesis.
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The electrochemical NO3 - reduction and its coupling with CO2 can provide novel and clean routes to synthesize NH3 and urea, respectively. However, their practical application is still impeded by the lack of efficient catalysts with desirable Faradaic efficiency (FE) and yield rate. Herein, we report the synthesis of molybdenum oxide nanoclusters anchored on carbon black (MoOx /C) as electrocatalyst. It affords an outstanding FE of 98.14 % and NH3 yield rate of 91.63â mg h-1 mgcat. -1 in NO3 - reduction. Besides, the highest FE of 27.7 % with a maximum urea yield rate of 1431.5â µg h-1 mgcat. -1 toward urea is also achieved. The formation of electron-rich MoOx nanoclusters with highly unsaturated metal sites in the MoOx /C heterostructure is beneficial for enhanced catalytic performance. Studies on the mechanism reveal that the stabilization of *NO and *CO2 NOOH intermediates are critical for the NH3 and urea synthesis, respectively.
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This work focuses on multi-stimuli-responsive materials with distinctive abilities, that is, color-changing and shape-memory. Using metallic composite yarns and polymeric/thermochromic microcapsule composite fibers, processed via a melt-spinning technique, an electrothermally multi-responsive fabric is woven. The resulting smart-fabric transfers from a predefined structure to an original shape while changing color upon heating or applying an electric field, making it appealing for advanced applications. The shape-memory and color-changing features of the fabric can be controlled by rationally controlling the micro-scale design of the individual fibers in the structure. Thus, the fibers' microstructural features are optimized to achieve excellent color-changing behavior along with shape fixity and recovery ratios of 99.95% and 79.2%, respectively. More importantly, the fabric's dual-response by electric field can be achieved by a low voltage of 5 V, which is smaller than the previously reported values. Above and beyond, the fabric is able to be meticulously activated by selectively applying a controlled voltage to any part of the fabric. The precise local responsiveness can be bestowed upon the fabric by readily controlling its macro-scale design. A biomimetic dragonfly with the shape-memory and color-changing dual-response ability is successfully fabricated, broadening the design and fabrication horizon of groundbreaking smart materials with multiple functions.
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Radishes are root vegetables that are rich in bioactive compounds and provide numerous health benefits, but the overall metabolic profiles of radish taproots and the metabolic differences among different edible types are not fully understood. In this research, we used UHPLC-Q-TOF-MS to identify the metabolites in cooked, processed and fruit radishes of ten varieties. In total, 264 metabolites belonging to 18 categories were detected. A multivariate analysis revealed that the metabolite composition differed among the three radish groups, and a comparative analysis showed that the significantly differentially accumulated metabolites were mainly amino acids and derivatives, lipids, flavonoids, hydroxycinnamate derivatives and carbohydrates. The accumulation of metabolites, particularly flavonoids, was greater in fruit radishes than in cooked and processed radishes. This work provides novel insights into the radish metabolomic profiles for assessment of the nutritional value of different edible radish types for humans.
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Raphanus , Humanos , Raphanus/química , Cromatografia Líquida de Alta Pressão , Metaboloma , Flavonoides/análise , Metabolômica , Suplementos NutricionaisRESUMO
Inspired by hook-and-loop fasteners, we designed a hydrogel network containing α-zirconium phosphate (ZrP) two-dimensional nanosheets with a high density of surface hydroxyl groups serving as nanopatches with numerous "hooks," while polymer chains with plentiful amine functional groups serve as "loops." Our multiscale molecular simulations confirm that both the high density of hydroxyl groups on nanosheets and the large number of amine functional groups on polymer chains are essential to achieve reversible interactions at the molecular scale, functioning as nano hook-and-loop fasteners to dissipate energy. As a result, the synthesized hydrogel possesses superior stretchability (>2100% strain), resilience to compression (>90% strain), and durability. Remarkably, the hydrogel can sustain >5000 cycles of compression with torsion in a solution mimicking synovial fluid, thus promising for potential biomedical applications such as artificial articular cartilage. This hook-and-loop model can be adopted and generalized to design a wide range of multifunctional materials with exceptional mechanical properties.
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Hidrogéis , Polímeros , PressãoRESUMO
Catalysts based on metallic NPs have shown high activities in heterogeneous catalysis, due to their high fractions of surface-active atoms, which, however, will lead to the sacrifices in stability and recycle of catalysts. In order to balance well the relationship between activity, stability, and recovery, in this paper, we have constructed a 3D mesoporous sphere structure assembled by N-doped carbon coated Ni/Pd NP heterojunctions (Ni/Pd@N-C). This obtained Ni/Pd@N-C has shown high catalytic activity, durability and recyclability for the hydrolytic dehydrogenation of ammonia borane (AB). Further investigations, including experimental and theoretical results, have shown that the unique structural features, the synergistic effect between Ni and Pd, and the coating of N-doped carbon layer are responsible for the good catalytic performance of Ni/Pd@N-C mesoporous spheres.
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In this work, a fast water-responsive shape memory hybrid polymer based on thermoplastic polyurethane (TPU) was prepared by crosslinking with hydroxyethyl cotton cellulose nanofibers (CNF-C) and multi-walled carbon nanotubes (CNTs). The effect of CNTs content on the electrical conductivity of TPU/CNF-C/CNTs nanocomposite was investigated for the feasibility of being a strain sensor. In order to know its durability, the mechanical and water-responsive shape memory effects were studied comprehensively. The results indicated good mechanical properties and sensing performance for the TPU matrix fully crosslinked with CNF-C and CNTs. The water-induced shape fixity ratio (Rf) and shape recovery ratio (Rr) were 49.65% and 76.64%, respectively, indicating that the deformed composite was able to recover its original shape under a stimulus. The TPU/CNF-C/CNTs samples under their fixed and recovered shapes were tested to investigate their sensing properties, such as periodicity, frequency, and repeatability of the sensor spline under different loadings. Results indicated that the hybrid composite can sense large strains accurately for more than 103 times and water-induced shape recovery can to some extent maintain the sensing accuracy after material fatigue. With such good properties, we envisage that this kind of composite may play a significant role in developing new generations of water-responsive sensors or actuators.
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Animals living in extremely cold plateau areas have shown amazing ability to maintain their bodies warmth, a benefit of their hair's unique structures and crimps. Investigation of hair crimps using a water-stimulated shape fixation effect would control the hair's crimpness with a specific wetting-drying process thereafter, in order to achieve the regulation of hair thermal insulation. The mechanism of hair's temporary shape fixation was revealed through FTIR and XRD characterizations for switching on and off the hydrogen bonds between macromolecules via penetration into and removal of aqueous molecules. The thermal insulation of hairs was regulated by managing the hair temporary crimps, that is, through managing the multiple reflectance of infrared light by hair hierarchical crimps from hair root to head.
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Conductive hydrogel combined with Ag/AgCl electrode is widely used in the acquisition of bio-signals. However, the high adhesiveness of current commercial hydrogel causes human skin allergies and pruritus easily after wearing hydrogel for electrodes for a long time. In this paper, a novel conductive hydrogel with good mechanical and conductive performance was prepared using polyvinyl alcohol (PVA), polyethylene glycol (PEG), and graphene oxide (GO) nanoparticles. A cyclic freezingâ»thawing method was employed under processing conditions of -40 °C (8 h) and 20 °C (4 h) separately for three cycles in sequence until a strong conductive hydrogel, namely, PVA/PEG/GO gel, was obtained. Characterization (Fourier transform infrared spectroscopy, nuclear magnetic resonance, scanning electron microscopy) results indicated that the assembled hydrogel was successfully prepared with a three-dimensional network structure and, thereafter, the high strength and elasticity due to the complete polymeric net formed by dense hydrogen bonds in the freezing process. The as-made PVA/PEG/GO hydrogel was then composited with nonwoven fabric for electrocardiogram (ECG) electrodes. The ECG acquisition data indicated that the prepared hydrogel has good electro-conductivity and can obtain stable ECG signals for humans in a static state and in motion (with a small amount of drift). A comparison of results indicated that the prepared PVA/PEG/GO gel obtained the same quality of ECG signals with commercial conductive gel with fewer cases of allergies and pruritus in volunteer after six hours of wear.