Search Results (4,505)

The development of sustainable and environmentally benign N-methylation methodologies is essential for enhancing sustainable synthetic practice in pharmaceutical manufacturing. In this study, we demonstrate that microwave heating (MWH) markedly enhanced the efficiency of cobalt-catalyzed N-methylation using methanol or methanol-d₄ as green C1 sources. Compared with conventional heating (CH), MWH enabled highly efficient syntheses of key pharmaceutical intermediates—including 6-dimethylamino-1-hexanol, imipramine hydrochloride, and butenafine hydrochloride—under milder conditions and shorter reaction times and without generating hazardous halogen-containing waste. UV–vis spectroscopic analysis revealed that MWH accelerated the transformation of Co(acac)₂ into catalytically active Co species by approximately four-fold, providing a mechanistic basis for the enhanced reactivity. We hypothesized that this effect was caused by the selective microwave heating of the catalyst, which in turn promoted the rapid generation of catalytically active species. Notably, MWH also significantly improved the N-trideuteromethylation of amines using methanol-d₄, achieving a 95% yield for imipramine-d₃ hydrochloride versus 32% under CH. Molecular dynamics simulations indicated that methanol-d₄ exhibited slower dipole relaxation and enhanced cluster fragmentation under microwave fields, improving catalyst–substrate contact, while kinetic isotope effects stabilized reactive intermediates. These synergistic effects account for the pronounced microwave promotion observed in deuterated systems. Overall, the combination of MWH and cobalt catalysis offers an energy-efficient, waste-minimizing, and environmentally benign strategy for the scalable synthesis of both methylated and deuterated amines. Full article

The research conducted in this paper is a practical example of the Design of Experiments methodology. In accordance with the assumptions of the experimental design, the authors drew attention to the problem: how should the spark plasma sintering process be planned to obtain the maximum amount of information needed to optimise the consolidation of the WC-6Co composite at the lowest possible cost? The DOE methodology—a powerful technique for investigating new processes and gaining knowledge about existing ones in order to optimise them for high performance—was employed in the study. The aim of the research was to optimise the consolidation of the spark-plasma sintering process of the WC-6Co composite using the DoE (Design of Experiments) methodology. Four sintering factors were selected for the study: sintering temperature (factor A, 1300–1400 °C); heating rate (factor B, 100–300 °C/min); sintering time (factor C, 150–600 s); and pressure (factor D, 40–50 MPa). Each consolidation factor was designed to cover three levels. The L9 orthogonal array was used. It was found that sintering temperature and heating rate had the greatest impact on apparent density. To validate the statistical model, sintering tests were performed at a temperature of 1380 °C, a heating rate of 100 °C/min, a sintering time of 150 s and a pressing pressure of 45 MPa. Validation analysis of the statistical model demonstrated consistency with the experimental results. The WC-6Co composite achieved an apparent density of 14.85 g/cm³, corresponding to 97.42% of the theoretical density, with a hardness of 1809 HV30 and total porosity of 2.583%. X-ray diffraction studies revealed the presence of tungsten carbide and cobalt in the structure. Full article

The brittleness of 18-karat purple gold originates from the AuAl₂ intermetallic compound. This study investigates the microstructural modification of the AuAl₂ intermetallic compound by adding silicon (Si) and cobalt (Co) and by rapid solidification in copper molds. The samples with alloy additions from a traditional investment casting were compared with copper mold casting for grain boundary characteristics using SEM, EBSD, and TEM. SEM micrographs showed a reduction in grain size of copper mold casting from approximately within 150–200 μm to within 12–20 μm. EBSD showed a narrow grain size distribution in the Si–Co-modified alloy than in the Si-modified alloy, using the copper mold casting technique. TEM observations show that grain boundaries were closely packed, with ~80 nm-sized voids. XRD confirmed that all alloys retained the AuAl₂ intermetallic phase, with peak broadening in the modified and fast-cooling samples indicating crystallographic refinement. These results confirm that Si-Co additions with a fast cooling rate effectively refine the microstructure of the AuAl₂ intermetallic compound, making the alloy less brittle while preserving the purple gold color. Full article

Autonomous mobile robots are transforming industries from e-commerce logistics to field exploration, but their effectiveness depends on onboard energy storage. This study addresses the challenge of selecting optimal battery technologies for autonomous mobile robots, balancing performance, energy efficiency, thermal stability, and cost across diverse applications. We focus on lithium-ion, lithium-polymer, and nickel-metal hydride batteries, the most common power solutions, each with distinct advantages and disadvantages in energy density, form factor, thermal stability, and cost. A dynamic modeling and simulation framework in MapleSim evaluated these chemistries under defined and representative operating conditions, tracking state of charge and temperature during charging and discharging. A Particle Swarm Optimization algorithm evaluated 37 battery configurations by thermal stability, energy efficiency, and cost across five use cases. Key results indicate that for logistics and warehousing, lithium nickel manganese cobalt oxide with graphite is optimal; for healthcare, lithium nickel manganese cobalt oxide with lithium titanate oxide excels; for manufacturing, lithium nickel cobalt aluminum oxide with graphite leads; for agricultural robots, lithium manganese oxide with graphite is best; and for exploration and mining, lithium iron phosphate with graphite is most reliable. These results provide a structured basis for battery selection, showing how simulation-driven, multi-criteria decision-making enhances energy management and operational reliability. Full article

The lack of integrity at the implant–abutment junction (IAJ) contributes to problems such as micromovements and microbial colonisation. This study aimed to (1) design a protocol for assessing microleakage at the IAJ using chromophore analysis not previously reported for this specific application, (2) compare gas and dye leakage between titanium (Ti) and cobalt chrome (CoCr) abutments, and (3) assess the effect of gold (Au) gilding on sealing. Forty abutments were divided into five groups: milled Ti (MTi); cast CoCr (CCoCr); milled CoCr (MCoCr); cast CoCr with Au gilding (CCoCrG); and milled CoCr with Au gilding (MCoCrG). Samples were subjected to internal pressure within a gas and dye reservoir. Chromophore analysis via UV-Vis spectrometer was used to calculate crystal violet leakage concentrations. Scanning electron microscopy (SEM) revealed close adaptation in the MTi and MCoCr groups, contrasting with irregularities in the CCoCr groups. Correspondingly, gas leakage and dye leakage were most prevalent in the CCoCr group. Fisher exact test demonstrated a statistically significant difference (p = 0.026) between the MCoCr and CCoCr abutments. While CCoCr exhibited the highest failure rate (62.5%), Au gilding demonstrated a trend toward reduced leakage (25% failure rate), though this did not reach statistical significance (p = 0.315). This chromophore analysis represents a viable and objective assessment of IAJ integrity. Full article

Lithium-ion batteries (LIBs) are pivotal for energy storage in electric vehicles and renewable systems, but how to effectively monitor their conditions and ensure their operational reliability is still a concern today. This study employs electrochemical impedance spectroscopy (EIS) to systematically investigate the evolution of impedance characteristics in nickel–cobalt–manganese oxide (NCM) lithium-ion batteries (LIBs) under varying states of charge (SOCs), states of health (SOHs), temperatures, and mechanical compression displacements. Results reveal that higher SOC and temperature reduce impedance by enhancing ion kinetics and interfacial activity, with $R_{ct}$ (charge transfer resistance) exhibiting a U-shaped dependence on SOC, minimized at 40–60%. As SOH declines from 100% to 80%, $R_{SEI}$ (SEI film resistance) and $R_{ct}$ increase progressively, reflecting SEI thickening and electrode degradation. Mechanical compression (0–8 mm) elevates all resistances, particularly $R_{ct}$ at high SOC, due to structural deformation and hindered diffusion. DRT (distribution of relaxation times) spectra highlight amplified low-frequency peaks with aging and low SOC, underscoring diffusion limitations. These findings elucidate multi-scale failure mechanisms, from interfacial polarization to structural instability, providing a framework for non-invasive health monitoring and lifetime prediction. Full article

Over the past two decades, organic semiconductors have attracted significant research interest due to their advantageous features, including low-cost fabrication, lightweight properties, and portability, for photonic device applications. In this study, nickel sulfide doped with cobalt $(\mathrm{N}\mathrm{i}\mathrm{S}/\mathrm{C}\mathrm{o})$ nanocomposites were successfully synthesized via a wet-chemical processing technique and used as a dopant in the active layer of thin-film organic solar cells (TFOSCs). The poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) blend was used as the active layer in this investigation. The devices were fabricated with $\mathrm{N}\mathrm{i}\mathrm{S}/\mathrm{C}\mathrm{o}$ nanocomposites at 1 wt%, 2 wt%, and 3 wt% in the active layer to determine the optimal dopant concentration. However, the experimental evidence clearly showed that the solar cell’s performance depends on the concentration of the $\mathrm{N}\mathrm{i}\mathrm{S}/\mathrm{C}\mathrm{o}$ nanocomposites. As a result, the highest power conversion efficiency (PCE) recorded in this experimental work was 6.11% at a 1% doping concentration, compared with 2.48% for the pristine reference device under AM 1.5G illumination (100 mW/cm²) in ambient conditions. The optical and electrical properties of the active layers are found to be strongly influenced by the inclusion of $\mathrm{N}\mathrm{i}\mathrm{S}/\mathrm{C}\mathrm{o}$ nanocomposites in the medium. However, the device doped with 1 wt% $\mathrm{N}\mathrm{i}\mathrm{S}/\mathrm{C}\mathrm{o}$ nanocomposite exhibits the highest absorption intensity, consistent with the better performance observed in this study, which can be attributed to the localized surface plasmon resonance (LSPR) effect. The optical and morphological characteristics of the synthesized $\mathrm{N}\mathrm{i}\mathrm{S}/\mathrm{C}\mathrm{o}$ nanocomposites were comprehensively analyzed using high-resolution transmission electron microscopy (HRTEM), high-resolution scanning electron microscopy (HRSEM), and additional complementary techniques. Full article

This work explores the effect of nitrogen ion implantation on the wettability of the cemented tungsten carbide–cobalt (WC–Co) tool surface used for wood-based panel machining. Nitrogen ions with an energy of 50 keV and a fluence of 1 × 10¹⁷ and 5 × 10¹⁷ cm⁻² were implanted into the surface layer of commercially available WC–Co indexable knives using the implanter without a mass-separated ion beam. The wettability was characterized by a contact angle instrument. The implantation of nitrogen ions into WC–Co tools caused a statistically significant and practically useful decrease in the contact angle. This obtained effect was dependent on the fluence of the implanted ions, and it changed over time. This effect may also explain the transfer from the workpiece and the surface capture of carbon atoms in the secondary structure formed during the machining of wood materials on tools with ion implantation. On the other hand, the layer of carbon on the surface of the tool formed during machining explains the reduction in friction coefficient observed in experiments and the increase in tool life during cutting. Full article

Skeletal muscle myopathy remains a significant cause of disability with limited treatment strategies. Advancements in tissue engineering have led to the development of borophosphate bioactive glasses (BPBGs) capable of enhancing skeletal muscle structure and function. Using a mouse model of severe myopathy (D2.mdx), we investigated muscle force, regeneration, angiogenesis and inflammation at 14, 70 and 140 days post-treatment (dpt). Tibialis anterior (TA) muscles of D2.mdx mice that received a single injection of cobalt oxide-doped BPBG (CoO-TRIM) particles exhibit greater active force, myofiber size, and regeneration through 70 dpt compared to control D2.mdx mice injected with Saline. Vascular endothelial growth factor (VEGF) was elevated up to 70 dpt in D2.mdx CoO-TRIM mice followed by increased muscle vascularity. As a marker of inflammation, interleukin (IL)-6 increased in D2.mdx CoO-TRIM mice compared to D2.mdx Saline controls at 14 dpt, with no differences at 70 or 140 dpt. No differences were observed in outcome measures between wild-type (WT) CoO-TRIM mice and WT Saline controls. We report that CoO-TRIM can stimulate VEGF production and promote restoration of muscle structure and function when inflammation is present. Local injection of an inorganic biomaterial alone can benefit myopathic skeletal muscle. Full article

Cellular therapy using human cardiac mesenchymal progenitor cells (hMPCs) for regenerative medicine is hindered by poor cell survival and senescence. Long non-coding RNAs (lncRNAs) are critical regulators of cellular processes, yet their role in cardiac aging remains underexplored. Here, lncRNA microarray profiling identified a novel lncRNA, XLOC_002543, upregulated in hMPCs preconditioned with cobalt protoporphyrin (CoPP), which was named CoPP-Induced and SFPQ-Associated RNA Transcript (CISAT) due to its interaction with splicing factor proline and glutamine rich (SFPQ), confirmed via RNA pull-down and immunoprecipitation. CISAT was the only highly expressed transcript among seven lnc-ANKMY1-5 variants in hMPCs, as shown by RT-PCR. Notably, CISAT expression decreased in aging/senescent hMPCs, correlating with elevated p16^INK4A, a senescence marker. Overexpression of CISAT reduced p16^INK4A levels; enhanced hMPC survival, proliferation, and migration; and increased antioxidant and anti-apoptotic protein expression, while CISAT knockdown reduced resistance to H₂O₂-induced oxidative stress. In vivo, intramyocardial transplantation of CISAT-overexpressed hMPCs in an immune-deficient murine myocardial infarction model reduced fibrosis, promoted angiogenesis, and preserved cardiac function. Mechanistically, CISAT interacts with SFPQ to regulate NRF2-mediated redox homeostasis and inhibits p38 MAPK phosphorylation, mitigating senescence and enhancing cell survival. These findings suggest that targeting CISAT to modulate redox signaling and p38 MAPK pathways in aging hMPCs could improve their therapeutic efficacy for myocardial repair in heart disease. Full article

China’s rapid electric vehicle (EV) market expansion—from 331,000 units in 2015 to over 9.5 million in 2023—is generating an unprecedented wave of retired lithium-ion batteries projected to exceed 94 TWh cumulatively by 2060, presenting critical challenges for sustainable resource management. While grid decarbonization can reduce use-phase emissions, the substantial embodied carbon in battery production (55–130 kg CO₂-eq/kWh) remains a critical challenge for achieving carbon neutrality. This study presents an integrated dynamic material flow analysis (MFA) and prospective life cycle assessment (LCA) framework—calibrated against the latest peer-reviewed literature—to quantify the carbon mitigation potential of battery recycling and second-life applications from 2020 to 2060. We evaluate four end-of-life management scenarios: baseline linear economy, enhanced recycling, second-life dominant, and synergistic optimization. Our results reveal that the synergistic scenario achieves the highest cumulative avoided emissions of 3844 Mt CO₂-eq, representing a 12.1-fold improvement over the baseline. Monte Carlo uncertainty analysis (n = 10,000) confirms robust scenario differentiation, with 100% probability that synergistic optimization outperforms enhanced recycling alone. Material security analysis shows that recycled supply can meet 100% of lithium, cobalt, nickel, and copper demand by 2060 under optimal management. These findings provide quantitative evidence for chemistry-differentiated battery management policies aligned with China’s dual carbon goals and the transition toward a sustainable circular economy. Full article

Background/Objectives: This technical report introduces an innovative hybrid digital workflow that integrates diagnostic plaster-cast scanning with intraoral scanning to produce an accurate 3D-printed model for fabricating distal-extension removable dental prostheses (RDPs). Methods: The technique aims to overcome the challenges of reproducing the mobile mucosa in free-end saddles, a critical factor for denture base accuracy and stability. The workflow began with conventional clinical procedures, including clinical examination, impression-making, and cast surveying. After performing the required mouth preparations according to the prosthetic design, the diagnostic cast was digitized and selectively modified to allow intraoral rescanning. The prepared teeth were then scanned intraorally and merged with the digitalized cast, producing a refined virtual model for CAD-based metal framework design. The framework was digitally designed, 3D-printed to verify adaptation, and cast in cobalt–chromium. Standard RDP fabrication steps were followed, including intraoral framework try-in, fabrication of acrylic bases, occlusal registration, tooth arrangement, and functional and esthetic try-in. The final prosthesis was installed and adjusted without the need for an additional impression. Results: This hybrid workflow enabled a highly accurate reproduction of the distal extension region, outperforming models derived solely from direct intraoral scanning. By digitally capturing the physiological morphology of the mobile mucosa, the method eliminates the need for the traditional altered-cast technique, reducing clinical time, technical sensitivity, and material costs. Conclusions: The proposed approach enhances denture base accuracy, improves adaptation, and promotes more uniform occlusal load distribution in free-end RDPs. This streamlined and reproducible digital protocol offers a clinically relevant advancement, with potential to improve prosthesis stability and long-term outcomes. Full article

Background: Microbial fermentation of non-digestible carbohydrates and proteins produce short-chain fatty acids (SCFAs), which are critical communication signals in the gut–adipose tissue axis. Individual SCFA can differentially modulate the adipocyte secretory profile and adipose tissue metabolic function; however, their dose-dependent effects on adipocyte function in combined inflammatory and hypoxic environmental conditions that reflect the obesity-associated adipose tissue phenotype remain unknown. Methods: Mature 3T3-L1 adipocytes were cultured for 24 h with lipopolysaccharide (LPS; 10 ng/mL) plus 100 µM of cobalt chloride (CoCl₂) to chemically induce hypoxia ± individual SCFAs, namely acetate (Ace), propionate (Pro), and butyrate (But), in a dose-dependent manner (0.25 mM, 0.5 mM, and 1 mM). Results: Ace, Pro and But reduced secretion of IL-6, MCP-1/CCL7 and Rantes/CCL5 in a dose-dependent manner, whereas Pro and But reduced MCP3/CCL7 secretion and only But reduced resistin and increased adiponectin secretion compared to control (p < 0.05). Intracellular protein expression of the ratio of phosphorylated–to–total NFκB p65 was reduced by 1 mM But, whereas the ratio of phosphorylated–to–total STAT3 expression was reduced by 1 mM Ace, Pro and But and 0.5 mM Pro and But compared to control (p < 0.05). There was no difference in insulin-stimulated or non-insulin-stimulated glucose uptake between control and any individual SCFAs (p > 0.05). Conclusions: Adipocyte adipokine secretory function in combined inflammation and hypoxic environmental conditions is dose-dependently attenuated by individual SCFA, which exhibit both individual and overlapping effects. Full article

The influence of Ni and Co additions on microstructure and mechanical properties of (CoCrCuTi)_100−xFe_x high-entropy alloys (HEAs) containing 10 or 15 at. % Fe was investigated. The base HEA consisted of dendritic C14 Laves phases with interdendritic Cu-rich FCC regions. When Ni in the range of 2.5 to 10 at. % was added, a reduction in the Cu-rich phase was observed. Conversely, Co additions in the same range initially increased the Cu-rich phase but eventually led to liquid-phase separation (LPS), forming distinct Cu-lean L1 liquid and Cu-rich L2 globular regions. The average Vickers hardness values of (CoCrCuTi)₉₀Fe₁₀ and (CoCrCuTi)₈₅Fe₁₅ HEAs were measured at 790 ± 33 HV and 760 ± 20 HV, respectively. The additions of Ni and Co decreased overall hardness values. However, while Ni additions caused greater microstructural refinement, Co additions eventually led to heterogeneity due to LPS. For instance, the Vickers hardness of (CoCrCuTi)₉₀Fe₁₀ with 2.5 at. % Ni reached a maximum of 706 ± 95 HV, decreasing in hardness and scatter to 646 ± 19 HV when Ni increased to 10 at. %. In contrast, Co additions led to a marked reduction in hardness, from 574 ± 114 HV at 2.5 at. % Co to 442 ± 246 HV at 10 at. % Co. The fracture toughness (KIC), determined using Vickers indentation testing, indicated that Ni additions reduce fracture toughness, while Co additions increase it. Full article

Sterol regulatory element-binding proteins (SREBPs) regulate lipid homeostasis and coordinate sterol metabolism and carotenogenesis in the astaxanthin-producing yeast Phaffia rhodozyma. While Sre1, the SREBP ortholog, and the site-2 protease Stp1 have been identified as essential components of this pathway in P. rhodozyma, additional factors involved in Sre1 processing or regulation remain unknown. In Aspergillus species, a signal peptide peptidase contributes to the activation of the SREBP ortholog, raising the possibility of a similar role in this yeast. In this work, we identified and characterized the P. rhodozyma signal peptide peptidase (SppA) homolog. Sequence analysis, domain prediction, and phylogenetic analyses supported its classification within the SPP family of intramembrane aspartyl proteases. To evaluate its functional role, ΔsppA mutants were constructed in genetic backgrounds with constitutive Sre1 activity, including the cyp61⁻ mutant and a strain expressing the active form of Sre1 (Sre1N). Deletion of SPPA did not alter sensitivity to clotrimazole or cobalt chloride, nor affect pigmentation, indicating that SppA is not required for Sre1 activation in P. rhodozyma. Transcriptomic analyses further showed that expression of SRE1 and of its known target genes remained unchanged upon SPPA deletion. Interestingly, the loss of SppA in the Sre1N background caused marked downregulation of genes associated with protein refolding and unfolded protein binding. In agreement with these transcriptional changes, the Sre1NΔsppA strain displayed increased sensitivity to dithiothreitol. These findings suggest that, although SppA is not involved in Sre1 activation in P. rhodozyma, it may play a role in protein stress-related processes. Future studies will be required to define the molecular mechanisms underlying this role and its integration with protein homeostasis networks. Full article