Search Results (158)

In recent years, significant attention has been directed toward the development of coating materials capable of tailoring surface properties for various functional applications. Transition metal nitrides, in particular, have garnered interest due to their superior physical and chemical properties, including high hardness, excellent wear resistance, and strong corrosion resistance. In this study, a fabrication process for CrN-based thin films was developed by combining reactive direct current magnetron sputtering (dcMS) with post-deposition annealing in air. CrN coatings were deposited by reactive dcMS using different argon-nitrogen (Ar:N₂) gas ratios (4:1, 3:1, 2:1, and 1:1), followed by annealing at 550 °C for 1.5 h in ambient air. XRD and EDS analysis revealed that this treatment results in the formation of a composite phase comprising CrN and Cr₂O₃. The resulting coating exhibited favorable mechanical and tribological properties, including a maximum hardness of 12 GPa, a low wear coefficient of 0.254 and a specific wear rate of 7.05 × 10⁻⁶ mm³/N·m, making it a strong candidate for advanced protective coating applications. Full article

Previously, we developed a porcine bronchial epithelial cell line designated as PBE cells and demonstrated that this cell line possesses functional Toll-like receptor 3 (TLR3), triggering the expressions of interferons (IFNs), antiviral factors, and inflammatory cytokines after its stimulation with the synthetic double-stranded ARN poly(I:C). In this work, we aimed to further characterize the PBE cell line as a reliable in vitro model for investigating swine influenza virus (SIV) infection and immunity. We evaluated the capacity of two SIV subtypes, H1N1 and H3N2, to replicate and induce cytopathic effects in PBE cells and to modulate the expressions of IFNs, antiviral factors, inflammatory cytokines, and negative regulators of the TLR signaling. We demonstrated that PBE cells are susceptible to both H1N1 and H3N2. SIV infected PBE cells inducing notable cytopathic effects as shown by the alteration of transepithelial electrical resistance (TEER) and cilia. Both SIV subtypes replicated in PBE cells in similar proportion and altered TEER values in comparable magnitudes. However, SIV H3N2 induced higher alterations of cilia than H1N1. SIV infection induced changes in all the immune factors evaluated in PBE cells. We detected quantitative differences when the subtypes H1N1 and H3N2 were compared. The fold expression changes of IFN-β, Mx1, Mx2, IFITM1, OAS1, OAS2, and OASL were higher in PBE cells infected with H3N2 than in cells challenged with H1N1. In addition, although both subtypes stimulated IL-8 expression, only the H3N2 induced IL-6 in infected PBE cells. SIV H1N1 and H3N2 also upregulated the expressions of the negative regulators A20, BCL-3, and MKP-1, while only H1N1 increased SIGIRR and Tollip. Immortalized respiratory cell lines from pigs can be useful in vitro systems for the study of viral infections and immune responses. These studies are of importance in the context of influenza infections not only for the agricultural field because pigs are natural hosts of these viruses but also because these animals serve as intermediate reservoirs of viruses that can threaten humans’ health. We demonstrated here that the PBE cell line can be a useful in vitro model to study SIV infection and immunity. Full article

Enhanced hard coatings with exceptional mechanical and thermal qualities have prompted substantial study into multicomponent nitride systems. TiAl(Si)N coatings have emerged as viable possibilities owing to their remarkable hardness, thermal stability, and oxidation resistance. This work involved the fabrication of thickness-varied TiAl(Si)N gradient coatings using reactive magnetron sputtering, employing a controlled modulation of aluminum and silicon content across the film thickness. Three samples, with thicknesses of ~400 nm, ~600 nm, and ~800 nm, were deposited under uniform Ar/N₂ gas flow ratios, and their microstructural, mechanical, and tribological characteristics were rigorously examined. SEM investigation demonstrated a significant change across thicknesses. XRD results validated the emergence of a predominant cubic TiAl(Si)N phase alongside a secondary hexagonal AlN phase, signifying partial phase segregation. The nanoindentation results indicated that Sample 2 exhibited the maximum hardness (~38 GPa) and Young’s modulus (~550 GPa) due to an optimized equilibrium between solid solution strengthening and nanocomposite production. Tribological testing revealed that Sample 1 displayed the lowest and most consistent friction coefficient, corresponding to its superior H/E and H3/E2 ratios, which signify improved elasticity and resistance to plastic deformation. The findings emphasize that the implementation of a compositional gradient, especially in the distribution of Si and Al, markedly affects the microstructure and performance of TiAl(Si)N coatings. Gradient structures enhance the microstructure, optimize hardness, and increase the friction coefficient. Ongoing refinement of gradient profiles and deposition parameters may further improve the characteristics of TiAl(Si)N coatings, facilitating their wider industrial use. Full article

The Multi-Parent Advanced Generation Inter-Cross (MAGIC) population is a powerful tool for dissecting the genetic architecture controlling natural variation in complex traits. In this work, the natural variation available in Arabidopsis thaliana MAGIC lines was evaluated by mapping quantitative trait loci (QTLs) for primary root length (PRL), lateral root number (LRN), lateral root length (LRL), adventitious root number (ARN), and adventitious root length (ARL). We analyzed the differences in the root structure of 139 MAGIC lines by measuring PRL, LRN, LRL, ARN, and ARL. Through QTL mapping, we identified new potential genes that may be responsible for these traits. Furthermore, we detected single-nucleotide polymorphisms (SNPs) in the coding regions of candidate genes in the founder accessions and the recombinant inbred lines (RILs). We identified a significant region on chromosome 1 associated with AR formation. This region encompasses 316 genes, many of which are involved in auxin and gibberellin signaling and homeostasis. We discovered SNPs in the coding regions of these candidate genes in the founder accessions that may contribute to natural variation in AR characteristics. Additionally, we found a novel gene that encodes a protein from the hydroxyproline-rich glycoprotein family, which exhibits differential SNPs in accessions with contrasting AR formation. This study provides genetic insights into the natural variation in AR numbers using MAGIC lines linked to hormone-related genes. Full article

Antigonon leptopus Hook. & Arn., commonly known as the chain of love, is a fast-growing leafy vine characterized by its pink or white heart-shaped flowers and is considered among the most invasive vine species in Guam. In Guam, the vine is considered to be a weed, but worldwide it is utilized in different folk medicine practices, such as for alleviating colds and tending to wounds. As a resource, A. leptopus is underutilized in Guam, prompting the search for possible pharmacological properties. A. leptopus contains a wide range of phytochemicals, including alkaloids, terpenoids, flavonoids, phenols, tannins, saponins, glycosides, and amino acids, which have been found to have many bioactive properties, including antioxidant, antimicrobial, antidiabetic, anti-inflammatory, and anticancer activities. Extraction methods varied according to specific research objectives, but overall, the most common methods involved were maceration, Soxhlet extraction, and hot extraction techniques. The application of green extraction methods, such as the use of supercritical CO₂, is currently lacking for this species. A. leptopus may serve as a promising source of bioactive compounds for the pharmaceutical and nutraceutical industries. Full article

In this study, as-cast ductile iron was austempered to produce austempered ductile iron (ADI). A CrAlSiN film was then deposited on the surface of ADI specimens using the cathodic arc deposition (CAD) method. The gas flow ratio of Ar/N₂ varied (2, 2.5, and 3) under different processing parameters, designated as S1, S2, and S3, respectively. The composition, structure, hardness, adhesion, and wear resistance of the coated specimens were analyzed to evaluate the effect of the gas flow ratio on surface hardness and abrasion resistance. The experimental results indicated that CrN/Al(Si)N nano-multilayered films were successfully synthesized using oppositely positioned dual targets (Cr and AlSi) reacting with N₂ gas during the CAD process. The coatings significantly enhanced the surface hardness and wear resistance of ADI. A comparison of the three coating conditions with varying gas flow ratios revealed that as the Ar/N₂ gas flow ratio decreased (i.e., N₂ gas flow increased), the surface hardness of the coated ADI specimens increased while the abrasion rate decreased. Among the tested conditions, S1 exhibited the highest hardness (1479 HV_0.1) and the lowest wear rate (1.6 × 10⁻⁶ g/m). Full article

Melanoma is one of the deathliest cancers worldwide and its incidence is reaching epidemic proportions. It is characterized by intrinsic chemo-resistance, low response rates to treatment and high metastatic potential. Because of this, new therapeutic options are permanently required. Tessaria absinthioides (Hook. & Arn.) DC. is a traditional medicinal plant, with antioxidant, selective cytotoxicity and anti-colorectal cancer evidence-based properties. This study aims to demonstrate the antitumoral and antimetastatic effects of T. absinthioides decoction (DETa), correlating in vitro and in vivo activities in a murine melanoma model. DETa was assayed on B16F0 murine non-metastatic cells to determine cytotoxicity and clonogenicity; while, in the B16F10 metastatic siblings, adhesion, wound healing migration and Boyden chamber invasion were studied. The ex vivo intestinal-sac model was used to quantify DETa bioavailability. Meanwhile, in C57BL6/wt mice, DETa was orally administered to evaluate its antitumoral and antimetastatic activities. DETa induced cytotoxicity in a dose- and time-dependent manner, affecting the long-term clonogenic survival, as well as the processes of adhesion and migration. Then, the intestinal absorption of DETa phenolics was proven, while the systemic anti-tumoral and anti-metastatic activities of DETa were confirmed. Results demonstrated that DETa has antimelanoma activity promoting this botanical compound as a relevant agent for cancer research and treatment. Full article

SiAlCN coatings were first obtained by the method of reactive evaporation of aluminum and plasma chemical activation of an organosilicon precursor in a hollow cathode arc discharge. The spectrum of discharge plasma was studied by optical emission spectroscopy under conditions of evaporation of Al in an Ar+N₂+hexamethyldisilazane vapor/gas medium, and it was shown that in the presence of a metal component in the plasma, not only did intensive activation of various components of the media occur but also an increased ionic effect on the surface of the coating was provided, with a deposition rate of up to 10.1 µm/h. The films had a dense and homogeneous structure and had a hardness of up to 31 GPa and good adhesion on stainless steel. The results of SEM, FTIR, and XRD showed that their structure was a nanocomposite consisting of an amorphous matrix based on SiCN and AlN with inclusions of AlCN nanocrystals. Full article

Geoffroea decorticans (Gill. ex Hook. & Arn) Burk. is a native tree of the dry areas of Northwestern and Central Argentina. Its seeds are considered waste material. The flour of seeds was analyzed as a source of nutritional and bioactive compounds. It has a low carbohydrate content, containing about 9% protein and between 10 and 14% fat. Approximately 82–84% of the fatty acids were unsaturated (oleic and linoleic acids). A high polyphenol and dietary fiber content was detected. Flavonoids and condensed tannins were the dominant phenolics. Polyphenol-enriched extracts were obtained from seed flour. The HPLC–ESI-MS/MS analysis of these concentrated extracts allowed for the identification of six compounds including C-glycosyl flavones (vitexin and isovitexin), type A procyanidins (dimer and trimer), and epicatequin gallate. Polyphenolic extracts showed antioxidant capacity and were able to inhibit enzymes (α-glucosidase and α-amylase) related to carbohydrate metabolism and (lipoxygenase) pro-inflammatory enzymes and were not toxic. Flour and polyphenolic extract from chañar seeds could be considered as new alternative ingredients for the formulation of functional foods, nutraceuticals, or food supplements. The use of the seed flour in addition to the pulp of the fruit along with the rest of the plant would encourage the propagation of this species resistant to extreme arid environments for commercial and conservation purposes to boost the regional economies of vulnerable areas of South America. Full article

This study focused on improving the mechanical properties of hemp-fiber-reinforced epoxy (HFRE) composites by modifying the surface of hemp fibers (HFs) using dielectric barrier discharge (DBD) plasma treatment. By exposing the fibers to different gas mixtures Ar, Ar+N₂, and Ar+O₂, the surface of the fibers was altered, adding functional groups, increasing surface roughness, and improving crystallinity. The researchers created HFRE composites using both untreated and plasma-treated HF, and then tested their mechanical properties. The results revealed that Ar+O₂ plasma treatment boosted both the tensile strength (by 15.2%) and energy absorption of the composites. To fine-tune the process, the response surface methodology (RSM) was used to determine the most important factors for optimizing the treatment: input power and treatment time. The ideal conditions were found to be 162.63 W of power and 10 min of treatment. These findings highlight the potential of DBD plasma as a reliable method for modifying the surface of hemp fibers, even with changes in the setup or reactor design. Overall, this approach shows great promise for industrial applications, providing an effective way to improve the strength and durability of HFRE composites for a variety of uses. Full article

Introduction: Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) are resistant to third-generation cephalosporins (3GCs), carbapenems, colistin, and tigecycline, making them a major public health priority, mainly within the developing world. However, their genomic epidemiology and possible determinants of resistance remain to be elucidated. Thus, this study aimed to perform a genomic characterization of E. coli and K. pneumoniae, both of which are resistant to last-line antibiotics, isolated from humans, poultry, and a dairy farm environment within Ecuador. Methods: This study analyzed nine 3GC-resistant E. coli isolates harboring the mcr-1 gene (six from poultry farms, two from human infections, and one from dairy farm compost), together with ten isolated colistin- and carbapenem-resistant K. pneumoniae clinical samples. Results: The E. coli isolates of human origin belonged to ST609 and phylogroup A, while the poultry and compost isolates belonged to phylogroups A, B1, E, and F. Diverse STs of the K. pneumoniae isolates included ST13 (five isolates), ST258 (four isolates), and ST86 (one isolate). Within the E. coli isolates, bla_CTX-M-55, bla_CTX-M-65, bla_CTX-M-15, and bla_CTX-M-2 genes were identified. This study also identified bla_CMY-2 and bla_KPC-3 (the latter in a carbapenem-susceptible isolate). In E. coli, the plasmid-borne mcr-1.1 gene was identified across all E. coli isolates within an IncI2 plasmid. Tigecycline-reduced susceptibility or resistance was related to missense amino acid substitutions coded in the marA and acrA genes. Within K. pneumoiae, bla_CTX-M-15 and bla_CTX-M-65, on the one hand, and bla_KPC-2 and bla_KPC-3, on the other, were associated with 3GC and carbapenem resistance, respectively. The bla_KPC-2 allele was identified in a ~10 kb Tn4401 transposon (tnpR–tnpA–istA–istB–bla_KPC-2–tnpA). In K pneumoniae, sequence data and phenotypic analysis linked a nonsense amino acid substitution coded in the mgrB (K3*) gene and missense amino acid substitutions coded in the marA, acrA, arnB, eptA, pmrB, pmrJ, and phoQ genes to colistin resistance. Meanwhile, tigecycline resistance was linked to nonsense and missense amino acid substitutions coded within the ramR sequence. Additionally, this study identified several integron structures, including Int191 (5′CS-dfrA14-3′CS), which was the most prevalent integron (Int) among E. coli and K. pneumoniae isolates in this study, followed by Int0 (5′CS-3′CS) and Int18 (5′CS-dfrA1-3′CS). Conclusions: These results contribute to the genomic epidemiology of MDR E. coli and K. pneumoniae in our setting and to the worldwide epidemiology in the One Health approach. Full article

To thrive as a successful weed in natural pastures, a plant must have not only highly competitive ability, but also the resilience to endure environmental stress and rapidly reclaim space once those stressors diminish and the other non-stress-tolerant plants die. Acanthostyles buniifolius [(Hook. ex Hook. & Arn.) R.M.King & H.Rob.], known as chirca, is a widely spread weed in South American natural pastures. It is known for its remarkable ability to withstand environmental stress and flourish in environments with prevalent stressors. The study evaluated the memory effect of water stress (drought) in chirca plants. The experiment was conducted in a greenhouse in a randomized block design with three replications. Treatments included Control = control plants without water deficit kept at 100% of the soil water-holding capacity (WHC); Primed plants = plants that were primed with water stress at 141 days after emergence (DAE) and received recurrent stress at 164 DAE; Naïve plants: plants that only experienced water stress at 164 DAE. To reach water stress, plants were not watered until the soil reached 15% of the soil’s WHC, which occurred ten days after water suppression in the priming stress and nine days after water suppression in the second stress. During periods without restriction, the pots were watered daily at 100% of the WHC. Primed plants exposed to water deficit better-maintained water status compared to the naïve plants; glycine betaine is an important defense mechanism against water deficit in chirca; naïve plants have a higher concentration of proline than plants under recurrent stress, demonstrating the greater need for protection against oxidative damage and needs greater osmotic regulation. Recurrent water deficits can prepare chirca plants for future drought events. These results show that chirca is a very adaptative weed and may become a greater threat to pastures in South America due to climate change, especially if drought becomes more frequent and severe. Full article

Discovering stable polymeric nitrogen phases and exploring their properties are crucial for energy storage and conversion, garnering significant attention. In this study, we investigate the formation possibility of a stable compound between Ar and N₂ through ab initio calculations under low-pressure conditions (0–100 GPa). The novel super nitride, Imm2 ArN_10, is designed to demonstrate robust thermodynamic stability under high pressures (91 GPa) and showcase the unique host–guest structure, in which guest atoms (Ar) are trapped inside the host polymeric N₁₀. Significantly, given the weak interaction between Ar and N atoms and a channel parallel to the c-crystallographic axis in ArN₁₀, we propose a novel method to stabilize the previously unknown polymeric nitrogen structure, Imm2-N₁₀, by removing the guest argon atoms from the natural channels of ArN₁₀. Imm2 ArN₁₀ and N₁₀ are thermodynamically and dynamically stable, with energy densities of 9.1 kJ g⁻¹ and 12.3 kJ g⁻¹, respectively—more than twice that of TNT. Additionally, ArN₁₀ and N₁₀ stand out as leading green energetic materials, boasting a superior explosion velocity of 17.56 km s⁻¹ and a detonation pressure of 1712 kbar, surpassing that of TNT. These findings significantly impact on the creation of pure nitrogen frameworks through chemical reactions involving inert elements under high pressure. Full article

The efficient management of IoT systems is fundamental to advancing smart cities while enabling the seamless integration of technologies that enhance urban sustainability and resilience. This paper introduces a Hierarchical Resource Management System (HRMS) tailored for IoT-enabled smart cities, emphasizing a decentralized architecture at the building level and scaling up to city-wide applications. At its core, the system integrates the Adaptive Resilient Node (ARN), designed to autonomously manage energy resources and ensure continuous operation through self-healing capabilities. This study outlines the HRMS architecture, operational workflows, and core functionalities, demonstrating how the hierarchical framework supports real-time decision-making, fault tolerance, and scalable resource allocation. The proposed system’s lightweight inter-node communication enhances workload balancing and system responsiveness, addressing critical challenges in urban energy management. Experimental evaluations show that the system achieves up to a 50% improvement in energy efficiency and a 30% reduction in downtime across various urban environments, highlighting its transformative potential for sustainable and resilient urban growth. Full article

Acid adaptation in Escherichia coli can induce antimicrobial resistance (AMR), posing challenges to global public health. We investigated the effects of acid adaptation on antimicrobial susceptibility, gene expression, zeta potential, and the outer membrane (OM) properties of Escherichia coli NCCP 13719. The acid-adapted (AA) strain exhibited increased resistance to multiple antimicrobials, with minimum inhibitory concentrations for colistin and polymyxin B increasing eight- and two-fold, respectively. Transcriptomic analysis identified 2225 differentially expressed genes, including upregulated genes associated with resistance to cationic antimicrobial peptides such as arnCTE, marA, and tolC. The upregulation of the arn operon suggests modifications in lipid A of lipopolysaccharides (LPS), reducing the negative charge of the OM and decreasing polymyxin binding affinity. Zeta potential measurements indicated a shift toward a less negative surface charge in the AA strain, which is consistent with LPS modifications. The AA strain also showed decreased OM permeability, which correlated with increased resistance to antimicrobials that penetrate the OM. These mechanisms collectively diminish the efficacy of polymyxins and highlight the potential for environmental factors to drive antimicrobial resistance. In conclusion, the acid adaptation of E. coli NCCP 13719 enhances AMR through changes in gene expression and OM modifications, highlighting the need for careful control of acidic environments during the treatment of medical devices and wastewater from food processing to prevent the emergence of resistant strains. Full article