This study systematically investigates the effect of CO2 activation duration (0-60 min at 900 °C) on electrospun polyacrylonitrile-derived carbon nanofibers (CNFs) for supercapacitor electrodes. The results reveal a nonlinear relationship between activation time and structural evolution. An intermediate duration of 50 min (CNF50) optimizes the microstructure, yielding the lowest ID/IG ratio, the highest sp2/sp3 carbon ratio, and a maximized microporous surface area of 658 m2 g−1. These characteristics enhance electrical conductivity and provide abundant ion-accessible sites. Consequently, the CNF50 electrode achieves a superior specific capacitance of 151.65 F g−1 at 0.5 A g−1, which represents a threefold improvement over non-activated CNFs. Furthermore, CNF50 demonstrates outstanding cycling stability, retaining 93.86
Mesenchymal stem cells (MSCs) exert immunomodulatory and regenerative effects primarily through their secretome, which comprises cytokines, growth factors, and extracellular vesicles. Although prolonged in vitro expansion has been reported to induce replicative senescence and alter MSC function, the functional consequences of passage-dependent changes in the MSC secretome remain incompletely characterized. In this study, we performed an integrated comparison of early- and late-passage MSC secretomes using THP-1 monocytic cells as an in vitro model to evaluate immunomodulatory and migratory responses. MSCs were characterized based on immunophenotype, proliferative capacity, and senescence-associated β-galactosidase activity. The biological effects of MSC secretomes on THP-1 cell viability, migration, and inflammatory responses were evaluated using MTT assays, chemotaxis assays, quantitative PCR, and ELISA. Early-passage MSC secretomes (EP-MSC-S) enhanced THP-1 cell viability, increased the expression of anti-inflammatory cytokines (IL-10 and TGF-β1), and reduced the transcript levels of pro-inflammatory mediators, including NF-κB, IL-1β, IL-6, and TNF-α. In contrast, late-passage MSC secretomes (LP-MSC-S) were associated with increased pro-inflammatory gene expression, enhanced migratory activity, and upregulation of CXCR4 and VEGF transcripts in THP-1 cells. Cytokine array profiling further demonstrated higher signal intensities of pro-inflammatory and chemotactic cytokines, including IL-1β, MCP-1, and MCP-2, in LP-MSC-S, whereas EP-MSC-S exhibited higher signal intensities of anti-inflammatory cytokines such as IL-4 and IL-13. Collectively, these findings provide functional evidence that MSC passage number is associated with coordinated changes in secretome composition and downstream immune and migratory responses in vitro. This study is limited by the use of an in vitro model, MSCs derived from a single donor, and gene-level pathway analysis without protein-level validation. Therefore, the findings should be interpreted as preliminary mechanistic associations that warrant further validation in multi-donor and in vivo models before translational applications can be considered. MSCs are known to influence immune responses mainly through the substances they release, known as the secretome. However, when MSCs are expanded in the laboratory for extended periods, they may undergo aging-related changes that could affect their biological properties. In this study, we compared secretomes obtained from early and late laboratory passages of MSCs using an in vitro immune cell model. We found that secretomes from early-passage MSCs were associated with a more anti-inflammatory profile, while those from late-passage MSCs showed features linked to increased inflammatory signaling and cell migration. These differences suggest that prolonged cell expansion may alter the functional characteristics of MSC secretomes. Because this study was conducted using a single donor and an in vitro model, the findings should be considered preliminary. Further research using multiple donors and more advanced models is needed to better understand how MSC passage number may influence their potential applications in immune-related conditions.
Coal is an abundant source of energy; however, the use of Pakistani coal is limited due to its high sulfur content, which causes environmental and health issues. Hence, pre-combustion desulfurization of coal is imperative for quality enhancement. The present study investigates the microbial desulfurization of coal from the Balochistan mine by using local bacterial strains, Bacillus pumilus and Bacillus licheniformis, isolated from the same coal mine, for their sustainability, adaptability, and local availability. Batch incubation experiments with a coal particle size of 75 and 150 µm and incubation periods of 7 and 14 days were conducted to evaluate the effect of particle size and incubation period on the sulfur removal efficiency. Proximate analysis was conducted in accordance with ASTM D3173, ASTM D3174, and ASTM D3175 to determine the moisture content (MC), ash content (AC), and volatile matter (VM), while ultimate analysis was performed using a CHNS analyzer. Additionally, XRD was used to determine changes in composition and structure before and after treatment. The results showed that microbial treatment increased calorific value, specifically at smaller particle sizes and longer incubation periods. The maximum sulfur removal achieved by B. licheniformis was 32.73
This study investigates the influence of niobium (Nb) on the heat-treatment behavior of multi-alloyed white cast iron containing 5 wt
The increasing concern over plastic waste disposal has led researchers to explore sustainable methods for converting waste into valuable products. This study investigates the catalytic pyrolysis of polystyrene waste (PSW) using SUZ-4 and ZSM-5 zeolite catalysts. SUZ-4 is synthesized from agricultural waste (rice husk), making it a more sustainable option. Results indicate that catalytic pyrolysis with SUZ-4 at a PSW-to-catalyst ratio of 1:0.033 at 350 degrees C produces an oil yield of 81.60 +/- 1.62 %, containing 49.34 % styrene and 21.22 % alpha-methylstyrene. Under the same conditions, ZSM-5 yields 77.73 +/- 1.24 % oil, with 33.18 % styrene and 18.58 % alpha-methylstyrene. In comparison, non-catalytic pyrolysis at 400 degrees C results in a 74.23 +/- 1.25 % oil yield. These findings demonstrate that the type of catalyst significantly influences product distribution. Both SUZ-4 and ZSM-5 zeolites have 10-membered ring pore systems, but their structural and acidic properties lead to different catalytic behaviors. SUZ-4's weaker Br & oslash;nsted acid sites limit excessive secondary cracking, enabling selective cracking. In contrast, ZSM-5 zeolite has stronger Br & oslash;nsted acid sites and an open, interconnected pore network, which promotes deeper cracking and aromatization, resulting in many types of aromatic compounds in the oil products. Catalytic pyrolysis also reduces the viscosity of the oil compared to non-catalytic pyrolysis. Differences in chemical composition also affect fuel properties such as heating value, pH, and color. Overall, catalytic pyrolysis offers advantages in terms of higher oil yield and lower operating temperatures. However, differences in catalyst type significantly impact oil composition, which in turn affects fuel quality.
