Search Results (3,312)

Electrochemical nitrogen reduction reaction (NRR) is a promising route for realizing green and sustainable ammonia synthesis under ambient conditions. However, one of the major challenges of currently available Single-atom catalysts (SACs) is poor catalytic activity and low catalytic selectivity, which is far away from the requirements of industrial applications. Herein, first-principle calculations within the density functional theory were performed to evaluate the feasibility of a single Mo atom anchored on a g-C₉N₁₀ monolayer (Mo@g-C₉N₁₀) as NRR electrocatalysts. The results demonstrated that the gas phase N₂ molecule can be sufficiently activated on Mo@g-C₉N₁₀, and N₂ reduction dominantly occurs on the active Mo atom via the preferred enzymatic mechanism, with a low limiting potential of −0.48 V. In addition, Mo@g-C₉N₁₀ possesses a good prohibition ability for the competitive hydrogen evolution reaction. More impressively, good electronic conductivity and high electron transport efficiency endow Mo SACs with excellent activity for electrocatalytic N₂ reduction. This theoretical research not only accelerates the development of NRR electrocatalysts but also increases our insights into optimizing the catalytic performance of SACs. Full article

Liquid-like surfaces have demonstrated immense potential in their ability to resist cell adhesion, a critical requirement for numerous applications across various domains. However, the conventional methodologies for preparing liquid-like surfaces often entail a complex multi-step polymer brush modification process, which is not only time-consuming but also presents significant challenges. In this work, we developed a single-cycle polymer brush modification strategy to build liquid-like surfaces by leveraging high-molecular-weight bis(3-aminopropyl)-terminated polydimethylsiloxane, which significantly simplifies the preparation process. The resultant liquid-like surface is endowed with exceptional slipperiness, effectively inhibiting bacterial colonization and diminishing the adherence of platelets. Moreover, it offers promising implications for reducing the dependency on anticoagulants in microfluidic systems constructed from PDMS, all while sustaining its antithrombotic attributes. Full article

Optically transparent polyimide (PI) films with good atomic oxygen (AO) resistance have been paid extensive attention as thermal controls, optical substrates for solar cells or other components for low Earth orbit (LEO) space applications. However, for common PI films, it is usually quite difficult to achieve both high optical transparency and AO resistance and maintain the intrinsic thermal stability of the PI films at the same time. In the current work, we aimed to achieve the target by using the copolymerization methodology using the fluorinated dianhydride 9,9-bis(trifluoromethyl)xanthene-2,3,6,7-tetracarboxylic dianhydride (6FCDA), the fluorinated diamine 2,2-bis [4-(4-aminophenoxy)phenyl]hexafluoropropane (BDAF) and the polyhedral oligomeric silsesquioxane (POSS)-containing diamine N-[(heptaisobutyl-POSS)propyl]-3,5-diaminobenzamide (DABA-POSS) as the starting materials. The fluoro-containing monomers were used to endow the PI films with good optical and thermal properties, while the silicon-containing monomer was used to improve the AO resistance of the afforded PI films. Thus, the 6FCDA-based PI copolymers, including 6FCPI-1, 6FCPI-2 and 6FCPI-3, were prepared using a two-step chemical imidization procedure, respectively. For comparison, the analogous PIs, including 6FPI-1, 6FPI-2 and 6FPI-3, were correspondingly developed according to the same procedure except that 6FCDA was replaced by 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA). Two referenced PI homopolymers were prepared from BDAF and 6FDA (PI-ref1) and 6FCDA (PI-ref2), respectively. The experimental results indicated that a good balance among thermal stability, optical transparency, and AO resistance was achieved by the 6FCDA-PI films. For example, the 6FCDA-PI films exhibited good thermal stability with glass transition temperatures (T_g) up to 297.3 °C, good optical transparency with an optical transmittance at a wavelength of 450 nm (T₄₅₀) higher than 62% and good AO resistance with the erosion yield (E_y) as low as 1.7 × 10⁻²⁵ cm³/atom at an AO irradiation fluence of 5.0 × 10²⁰ atoms/cm². The developed 6FCDA-PI films might find various applications in aerospace as solar sails, thermal control blankets, optical components and other functional materials. Full article

Porous hydrogels have brought more advantages than conventional hydrogels when used as chromatographic materials, controlled release vehicles for drugs and proteins, matrices for immobilization or separation of molecules and cells, or as scaffolds in tissue engineering. Polysaccharide-based porous hydrogels, in particular, can address challenges related to bioavailability, solubility, stability, and targeted delivery of natural antioxidant compounds. Their porous structure enables the facile encapsulation and controlled release of these compounds, enhancing their therapeutic effectiveness. In this context, in the present study, the cryogelation technique has been adopted to prepare novel dextran (Dx)-based porous hydrogels embedding polyphenol-rich natural extract from Picea abies spruce bark (SBE). The entrapment of the SBE within the Dx network was proved by FTIR, SEM, and energy-dispersive X-ray spectroscopy (EDX). SEM analysis showed that entrapment of SBE resulted in denser cryogels with smaller and more uniform pores. Swelling kinetics confirmed that higher concentrations of Dx, EGDGE, and SBE reduced water uptake. The release studies demonstrated the effective stabilization of SBE in the Dx-based cryogels, with minimal release irrespective of the approach selected for SBE incorporation, i.e., during synthesis (~3–4%) or post-synthesis (~15–16%). In addition, the encapsulation of SBE within the Dx network endowed the hydrogels with remarkable antioxidant and antimicrobial properties. These porous biomaterials could have broad applications in areas such as biomedical engineering, food preservation, and environmental protection, where stability, efficacy, and safety are paramount. Full article

Microbial biofilm formation on medical devices paves the way for device-associated infections. Staphylococcus epidermidis is one of the most common strains involved in such infections as it is able to colonize numerous devices, such as intravenous catheters, prosthetic joints, and heart valves. We previously reported the antibiofilm activity against S. epidermidis of pentadecanoic acid (PDA) deposited by drop-casting on the silicon-based polymer poly(dimethyl)siloxane (PDMS). This material exerted an antibiofilm activity by releasing PDA; however, a toxic effect on bacterial cells was observed, which could potentially favor the emergence of resistant strains. To develop a PDA-functionalized material for medical use and overcome the problem of toxicity, we produced PDA-doped PDMS by either spray-coating or PDA incorporation during PDMS polymerization. Furthermore, we created a strategy to assess the kinetics of PDA release using ADIFAB, a very sensitive free fatty acids fluorescent probe. Spray-coating resulted in the most promising strategy as the concentration of released PDA was in the range 0.8–1.5 μM over 21 days, ensuring long-term effectiveness of the antibiofilm molecule. Moreover, the new coated material resulted biocompatible when tested on immortalized human keratinocytes. Our results indicate that PDA spray-coated PDMS is a promising material for the production of medical devices endowed with antibiofilm activity. Full article

In the eukaryotic cells, the ubiquitin–proteasome system (UPS) plays a crucial role in the intracellular protein turnover. It is involved in several cellular functions such as the control of the regular cell cycle progression, the immune surveillance, and the homeostasis. Within the 20S proteasome barrel-like structure, the catalytic subunits, β1, β2 and β5, are responsible for different proteolytic activities: caspase-like (C-L), trypsin-like (T-L) and chymotrypsin-like (ChT-L), respectively. The β5 subunit is particularly targeted for its role in antitumor activity: the synthesis of β5 subunit inhibitors could be a promising strategy for the treatment of solid and hematologic tumors. In the present work, we performed two combination studies of AM12, a recently developed synthetic proteasome inhibitor, with curcumin and quercetin, two nutraceuticals endowed of many pharmacological properties. We measured the combination index (CI), applying the Chou and Talalay method, comparing the two studies, from 50% to 90% of proteasome inhibition. In the case of the combination AM12 + curcumin, an increasing synergism was observed from 50% to 90% of proteasome inhibition, while in the case of the combination AM12 + quercetin an additive effect was observed only from 50% to 70% of β5 subunit inhibition. These results suggest that combining AM12 with curcumin is a more promising strategy than combining it with quercetin for potential therapeutic applications, especially in treating tumors. Full article

We apply a well known technique of theoretical physics, known as geometric algebra or Clifford algebra, to linear electrical circuits with nonsinusoidal voltages and currents. We rederive from the first principles the geometric algebra approach to the apparent power decomposition. The important new point consists of endowing the space of Fourier harmonics with a structure of a geometric algebra (it is enough to define the Clifford product of two periodic functions). We construct a set of commuting invariant imaginary units which are used to define impedance and admittance for any frequency. Full article

The aim of this paper is to introduce to a pair of fuzzy graphic rational F-contraction multivalued mappings and to study the necessary condition for the existence of common fixed points of fuzzy multivalued mappings in the setup of generalized parametric metric space endowed with a directed graph. A non-trivial example is presented to support the results presented herein. Our results improve and extend some recent results in the existing literature. Full article

In this review, we introduce the concept of cell competition, which occurs between heterogeneous neighboring cell populations. Cells with higher relative fitness become “winners” that outcompete cells of lower relative fitness (“losers”). We discuss the idea of super-competitors, mutant cells that expand at the expense of wild-type cells. Work on adult stem cells (ASCs) has revealed principles of neutral competition, wherein ASCs can be stochastically lost and replaced, and of biased competition, in which a winning ASC with a competitive advantage replaces its neighbors. Germline stem cells (GSCs) are ASCs that are uniquely endowed with the ability to produce gametes and, therefore, impact the next generation. Mechanisms of GSC competition have been elucidated by studies in Drosophila gonads, tunicates, and the mammalian testis. Competition between ASCs is thought to underlie various forms of cancer, including spermatocytic tumors in the human testis. Paternal age effect (PAE) disorders are caused by de novo mutations in human GSCs that increase their competitive ability and make them more likely to be inherited, leading to skeletal and craniofacial abnormalities in offspring. Given its widespread effects on human health, it is important to study GSC competition to elucidate how cells can become winners or losers. Full article

Despite considerable progress, high-performing durable catalysts operating under large current densities (i.e., >1000 mA/cm²) are still lacking. To discover platinum group metal-free (PGM-free) electrocatalysts for sustainable energy, our research involves investigating layered topological magnetic materials (semiconducting ferromagnets) as highly efficient electrocatalysts for the hydrogen evolution reaction under high current densities and establishes the novel relations between structure and electrochemical property mechanisms. The materials of interest include transition metal trihalides, i.e., CrCl₃, VCl₃, and VI₃, wherein a structural unit, the layered structure, is formed by Cr (or V) atoms sandwiched between two halides (Cl or I), forming a tri-layer. A few layers of quantum crystals were exfoliated (~50−60 nm), encapsulated with graphene, and electrocatalytic HER tests were conducted in acid (0.5M H₂SO₄) and alkaline (1M KOH) electrolytes. We find a reasonable HER activity evolved requiring overpotentials in a range of 30–50 mV under 10 mA cm⁻² and 400−510 mV (0.5M H₂SO₄) and 280−500 mV (1M KOH) under −1000 mA cm⁻². Likewise, the Tafel slopes range from 27 to 36 mV dec⁻¹ (Volmer–Tafel) and 110 to 190 mV dec⁻¹ (Volmer–Herovsky), implying that these mechanisms work at low and high current densities, respectively. Weak interlayer coupling, spontaneous surface oxidation, the presence of a semi-oxide subsurface (e.g., O–CrCl₃), intrinsic Cl (or I) vacancy defects giving rise to in-gap states, electron redistribution (orbital hybridization) affecting the covalency, and sufficiently conductive support interaction lowering the charge transfer resistance endow the optimized adsorption/desorption strength of H^* on active sites and favorable electrocatalytic properties. Such behavior is expedited for bi-/tri-layers while exemplifying the critical role of quantum nature electrocatalysts with defect sites for industrial-relevant conditions. Full article

Background/Objectives: In the contest of agro-industrial waste valorization, we focused our attention on lentil seed coats as a source of health-promoting phytochemicals possibly useful in managing inflammatory bowel diseases (IBDs), usually characterized by inflammation and altered intestinal motility. Methods: Both traditional (maceration) and innovative microwave-assisted extractions were performed using green solvents, and the anti-inflammatory and spasmolytic activities of the so-obtained extracts were determined through in vitro and ex vivo assays, respectively. Results: The extract obtained through the microwave-assisted procedure using ethyl acetate as the extraction solvent (BEVa) proved to be the most useful in inflammation and intestinal motility management. In LPS-activated Caco-2 cells, BEVa down-regulated TLR4 expression, reduced iNOS expression and the pro-inflammatory cytokine IL-1 production, and upregulated the anti-inflammatory cytokine IL-10 production, thus positively affecting cell inflammatory responses. Moreover, a significant decrease in the longitudinal and circular tones of the guinea pig ileum, with a reduction of transit speed and pain at the ileum level, together with reduced transit speed, pain, and muscular tone at the colon level, was observed with BEVa. HPLC separation combined with an Orbitrap-based high-resolution mass spectrometry (HRMS) technique indicated that 7% of all the identified metabolites were endowed with proven anti-inflammatory and antispasmodic activities, among which niacinamide, apocynin, and p-coumaric acid were the most abundant. Conclusions: Our results suggest that lentil hull extract consumption could contribute to overall intestinal health maintenance, with BEVa possibly representing a dietary supplementation and a promising approach to treating intestinal barrier dysfunction. Full article

This study examines the impact of international trade activities on employment in the Portuguese textiles and apparel industry from 2010 to 2017. It finds evidence that imports and exports have a persistent, negative, and significant effect on overall job creation, with this impact intensifying over the long-run. Additionally, the increasing elasticity of substitution between imports and exports indicates that private companies of this industry have benefited from a win–win situation characterised by higher production volumes and lower marginal costs. By applying an unsupervised machine-learning method, followed by a discrete choice analysis to infer the firm-level propensity to possess green capital, we identify a phenomenon termed the green international trade paradox. This study also reveals that international trade activities positively influence green job creation in firms lacking green capital if and only if these players are engaged in international markets while negatively affecting firms already endowed with green technologies. As such, empirical results suggest that the export-oriented economic model followed over the last decade by the Portuguese textiles and apparel industry has not necessarily generated new domestic employment opportunities but has significantly altered the magnitude and profile of skill requirements that employers seek to identify in new workforce hires. Full article

In the context of China’s large country with small farmers, agricultural socialized services are regarded as an important way for small farmers to organically connect with modern agriculture and provide ideas for improving agricultural green total factor productivity (AGTFP). Based on data from 1066 farmers from the China Land Economy Survey (CLES), this paper takes net carbon sink as the environmental output variable, adopts the Cobb–Douglas production function for stochastic frontier method estimation, and measures the AGTFP based on the stochastic frontier analysis method with an output-oriented distance function. At the same time, through the construction of intermediary effect and regulatory effect models, it empirically analyzes the impact and mechanism of agricultural socialized services on farmers’ AGTFP from the perspective of factor allocation. The study found that agricultural socialized services not only significantly promote AGTFP, but also that the effect of AGTFP improvement is more significant as the degree of participation in agricultural socialized services increases. The main results have passed a series of robustness tests. Further research found that agricultural socialized services promote the improvement of AGTFP through the intermediary role of improving the scale of farmland and the level of agricultural green technology adoption. Off-farm employment of the rural labor force has a positive regulatory effect between agricultural socialized services and AGTFP. Therefore, it is recommended to further play the role of agricultural socialized services in optimizing the allocation of production factors and to motivate agricultural socialized service organizations to provide multiple green production services for farmers through policy support or subsidies, enhance the service capacity of agricultural socialized service organizations, and provide precise services by fully considering the differences in the endowment of production factors among farmers, as well as take multiple measures and make solid and steady progress in promoting the sustainable development of agriculture. Full article

Background/Objectives: Supported by a comparative study between conventional, grinding, and microwave techniques, a mild and versatile method based on the [1 + 3] cycloaddition of 2-((3-nitrophenyl)diazenyl)malononitrile to tether pyrazole and pyrimidine derivatives in good yields was used. Methods: The newly synthesized compounds were analyzed with IR, ¹³C NMR, ¹H NMR, mass, and elemental analysis methods. The products show interesting precursors for their antiproliferative anti-breast cancer activity. Results: Pyrimidine-containing scaffold compounds 9 and 10 were the most active, achieving IC₅₀ = 26.07 and 4.72 µM against the breast cancer MCF-7 cell line, and 10.64 and 7.64 µM against breast cancer MDA-MB231-tested cell lines, respectively. Also, compounds 9 and 10 showed a remarkable inhibitory activity against the Hsp90 protein with IC₅₀ values of 2.44 and 7.30 µM, respectively, in comparison to the reference novobiocin (IC₅₀ = 1.14 µM). Moreover, there were possible apoptosis and cell cycle arrest in the G1 phase for both tested compounds (supported by CD1, caspase-3,8, BAX, and Bcl-2 studies). Also, the binding interactions of compound 9 were confirmed through molecular docking, and simulation studies displayed a complete overlay into the Hsp90 protein pocket. Conclusions: Compounds 9 and 10 may have apoptotic antiproliferative action as Hsp90 inhibitors. Full article

Resource-based regions are built upon the endowment of abundant natural resources; however, they often fall into development dilemmas due to the depletion of natural resources and ecological environmental regulations. How to achieve transformative development relying on the original industrial base is an important choice for the sustainable development of resource-based regions. This paper takes Heilongjiang Province, a resource-based province in China, as the research area and analyzes its process and strategies of transformative development from the perspective of industrial spatial patterns. The results show that: (1) There is spatial convergence in the development of secondary industry and industry in Heilongjiang Province from 2011 to 2020. The construction industry does not have spatial convergence, and the development of tertiary industry and its sub-industry does not have spatial convergence on the whole. (2) From 2011 to 2022, the development of secondary and tertiary industries in Heilongjiang Province formed a relatively stable spatial correlation network with good accessibility, but the hierarchy of network structure is not obvious, and the correlation strength and stability of the network need to be improved. (3) Harbin, Hegang, Qitaihe and other regions occupy a relatively central position in the spatial association network of the secondary industry; Harbin, Jiamusi, Suihua and other regions are in a leading position in the spatial association network of the tertiary industry which plays an important role as an intermediary bridge; other regions are in a relatively marginal position in the spatial association network of the industrial industry. (4) The increase in network density can effectively promote the development of the secondary and tertiary industries, and the network level and network efficiency will inhibit the development of the secondary and tertiary industries. The increase in network density will narrow the spatial difference of the secondary and tertiary industries, and the decrease in network level and network efficiency can effectively promote the spatial balance of the development of the secondary and tertiary industries. (5) The closer the spatial correlation between each region and other regions, the more benefits from the overall network, the more conducive to the development of local secondary and tertiary industries. The aforementioned results indicate that Heilongjiang Province is constructing a spatial pattern characterized by the complementarity of the primary, secondary and tertiary industries, which serves as a strategy for the transformative development of resource-based regions. Full article