Search Results (5,137)

In this study, semi-interpenetrating polymer network (semi-IPN) hydrogels based on methacrylated dextran and native inulin were designed as biodegradable carriers for the colon-specific delivery of uracil as a model antitumor compound. The hydrogels were synthesized via free-radical polymerization, using diethylene glycol diacrylate (DEGDA) as a crosslinking agent at varying concentrations (5, 7.5, and 10 wt%), and their structural, thermal, and biological properties were systematically evaluated. Fourier transform infrared spectroscopy (FTIR) confirmed successful crosslinking and physical incorporation of uracil through hydrogen bonding. Concurrently, differential scanning calorimetry (DSC) revealed an increase in glass transition temperature (T_g) with increasing crosslinking density (149, 153, and 156 °C, respectively). Swelling studies demonstrated relaxation-controlled, first-order swelling kinetics under physiological conditions (pH 7.4, 37 °C) and high gel fraction values (84.75, 91.34, and 94.90%, respectively), indicating stable network formation. SEM analysis revealed that the hydrogel morphology strongly depended on crosslinking density and drug incorporation, with increasing crosslinker content leading to a more compact and wrinkled structure. Uracil loading further modified the microstructure, promoting the formation of discrete crystalline domains within the semi-IPN hydrogels, indicative of physical drug entrapment. All formulations exhibited high encapsulation efficiencies (>86%), which increased with increasing crosslinker content, consistent with the observed gel fraction values. Simulated in vitro gastrointestinal digestion showed negligible drug release under gastric conditions and controlled release in the intestinal phase, primarily governed by crosslinking density. Antimicrobial assessment against Escherichia coli and Staphylococcus epidermidis, used as an initial or indirect indicator of cytotoxic potential, revealed no inhibitory activity, suggesting low biological reactivity at the screening level. Overall, the results indicate that DEGDA-crosslinked dextran/inulin semi-interpenetrating (semi-IPN) hydrogels represent promising carriers for colon-targeted antitumor drug delivery. Full article

Biological upgrading of biogas to biomethane is a promising power-to-gas technology with a low environmental footprint. However, due to the lower conversion rates, long-term investigations on mesophilic trickle-bed reactors (TBRs) remain scarce. This study systematically evaluated the performance of lab-scale mesophilic TBRs operated for more than 600 days. A TBR packed with plastic media (Kaldnes K1) consistently achieved methane (CH₄) concentrations > 96% at GRTs as short as 2.2 h, and down to 1 h under a mild overpressure (0.1 bar). Mild pressurization (0.1 bar) enabled methane production rates (MPRs) of up to 2.8 NL L⁻¹ d⁻¹ under a hydrogen loading rate (HLR) of 14.9 NL L⁻¹ d⁻¹. At atmospheric pressure, stable MPRs of approximately 2 NL L⁻¹ d⁻¹ were achieved under an HLR of 9 NL L⁻¹ d⁻¹. Microbial community analysis revealed strong enrichment of hydrogenotrophic Methanobacterium (>90% relative abundance) in both suspended and attached biomass, confirming the establishment of a stable methanation pathway. Overall, the results demonstrate that high-rate and stable biomethanation can be achieved under mesophilic conditions at GRTs as low as 1 h, providing new insights for cost-effective biomethane production. Full article

Infectious endometritis is a primary cause of subfertility in mares. Many manuals and guidelines are available for administering intrauterine infusions of antibiotics and biofilm-disrupting solutions, detailing concentrations, vehicle solutions, and buffers. However, the stability of these combinations has not been documented. Therefore, our study investigated how factors such as storage temperature, concentration, buffer types, combinations of biofilm disruptors, and vehicle solutions affected pH stability over 24 h in uterine infusion preparations commonly used by veterinary theriogenologists to treat endometritis in mares. In experiment 1, amikacin, ampicillin, ceftiofur, ciprofloxacin, gentamicin, penicillin G potassium, penicillin G procaine, and ticarcillin clavulanate were diluted in saline and lactated Ringer’ s solution and stored at 5 ° C, 21 ° C, and 37 ° C for 24 h. Solutions were evaluated for pH and physical characteristics at 0, 1, 3, 6, and 24 h after storage. In experiment 2, 1- and 2-g doses of amikacin, ampicillin, and gentamicin were compared, evaluating the same volume at different concentrations and their stability over 24 h. Experiment 3 combined biofilm chelators (i.e., Tris-EDTA, hydrogen peroxide, and dimethyl sulfoxide) with antibiotic solutions and evaluated interactions among products. Experiment 4 compared the stability of each antibiotic diluted in saline and lactated Ringer’ s solution. Statistical analysis was performed using GraphPad Prism 9.3.0. Significance was set at p < 0.05. The results indicated that the stability of antibiotic solutions for uterine infusions in mares is significantly influenced by storage conditions and pH fluctuations. Solutions containing aminoglycosides showed an increase in pH over time, suggesting that buffering agents like sodium bicarbonate can enhance stability. In contrast, other antibiotics exhibited a decrease in pH, particularly at elevated temperatures, which may reduce their effectiveness. In conclusion, the pH stability of uterine infusions is affected by various storage conditions and vehicles, underscoring the importance of evaluating antibiotic treatments for quality control. While pH changes were observed, the potential impact on the overall stability or antimicrobial activity of the solutions requires further investigation. Full article

Traditional polysaccharide extraction suffers from low efficiency and high energy consumption, while deep eutectic solvents (DESs) are promising sustainable solvents. This study used DES ChCl-LA (1:2) with ultrasonic assistance to extract polysaccharides from red alga A.taxiformis. Optimized via single-factor experiments and response surface methodology (350 W, 1:30 g/mL, 75 °C), the yield reached 11.28% ± 0.50% (1.5 times higher than that obtained by water extraction). Structural characterization revealed that the DES extract was an acidic polysaccharide, mainly composed of galactose (89.2%), glucose (4.9%), xylose (4.9%), and glucuronic acid (1.0%), with a weight-average molecular weight of 99.88 kDa. Density functional theory and molecular dynamics simulations showed that ChCl-LA enhanced galactose solubility via stronger hydrogen bonding (−25.33 vs. −5.06 kcal/mol for water). Notably, the immunological activity of the DES-extracted polysaccharide was significantly compromised compared to the water-extracted counterpart (p < 0.05). At a concentration of 0.25 mg/mL, the water-extracted polysaccharide-treated group exhibited a 33.98% higher neutral red phagocytosis rate in macrophages, a nitric oxide (NO) secretion level of 34.14 μmol/L (94.98% higher) compared with the DES-extracted polysaccharide group, as well as significantly higher secretion levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). The observed disparity in bioactivity is likely due to the distinct chemical profiles resulting from the two extraction methods, including the significantly reduced molecular weight and potential alterations of sulfation degree, monosaccharide composition, and protein content in the DES-extracted polysaccharide. This mechanistic perspective is supported by the relevant literature on the structure–activity relationships of polysaccharides. This study demonstrates the potential of ChCl-LA and elucidates the complex effects of extraction methods on polysaccharide’s structure and function, thereby informing the high-value utilization of A. taxiformis in functional foods. Full article

Electrocatalytic hydrogenation (ECH) represents an environmentally friendly pathway for converting 5-hydroxymethylfurfural (HMF) into the high-value chemical 2,5-bis(hydroxymethyl)furan (BHMF). However, its selectivity and Faradaic efficiency are often constrained by competitive hydrogen evolution at the cathode and insufficient supply of active hydrogen at the surface. To address this challenge, this study developed an Ir-decorated copper oxide nanowire catalyst (denoted as CuIr) featuring a hydrogen-rich adsorption (H_ads) surface. The incorporation of Ir significantly enhances the catalyst’s water dissociation capacity, creating abundant H_ads sources that selectively accelerate HMF hydrogenation while suppressing side reactions. Under a mild applied potential of −0.45 V vs. RHE and a current density of approximately −20 mA cm⁻², the optimal CuIr₄₀ catalyst achieved near-complete conversion of HMF (99%), a BHMF yield of 99%, and a high Faradaic efficiency of 97% within 120 min of electrolysis. Mechanistic studies reveal that this catalytic leap stems from the synergistic functional interaction between Cu and Ir sites in substrate activation and hydrogen supply. This work presents a novel strategy for designing efficient electrocatalysts for biomass hydrogenation by regulating surface H_ads concentration. Full article

This study reports the fabrication of chitosan/carboxymethyl cellulose (C/M) nanocomposites by electrolyte gelation–spray drying and the evaluation of their antibacterial performance as carriers for the antibiotic ampicillin. Chitosan (C), a cationic biopolymer derived from chitin, was combined with the anionic polysaccharide carboxymethyl cellulose (M) at different mass ratios to form stable nanocomposites via electrostatic interactions and then collected in a spray dryer. The resulting particles exhibited mean diameters ranging from 800 to 1500 nm and zeta potentials varying from +90 to −40 mV, depending on the C/M ratio. The optimal formulation (C/M = 2:1 ratio) achieved a high recovery yield (71.1%), lower PDI (0.52), and ampicillin encapsulation efficiency EE (82.4%). Fourier transform infrared spectroscopy (FTIR) confirmed the presence of hydrogen bonding and ionic interactions among C/M, and ampicillin within the nanocomposite matrix. The nanocomposites demonstrated controlled ampicillin release and pronounced antibacterial activity against Staphylococcus aureus, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 3.2 µg/mL and 5.3 µg/mL, respectively, which were lower than those of free ampicillin. These results indicate that the chitosan/carboxymethyl cellulose nanocomposites are promising, eco-friendly carriers for antibiotic delivery and antibacterial applications. Full article

Willows (genus Salix) are versatile plants with applications in construction, medicine, and biomass fuel in North America. Advances in breeding have improved willow clones for higher yields and pest resistance, but the chemical content and distribution across different plant parts remain poorly understood. This study examined the variation in chemical elements (carbon, hydrogen, nitrogen, sulfur, chlorine, and ash) across six willow clones (India, Jorr, Olof, Otisco, Preble, and Tora) and three tissue types (wood, bark, twigs). We also compared freeze-drying and oven-drying methods to assess their impact on chemical content. Freeze-dried samples generally exhibited higher carbon and hydrogen concentrations than oven-dried samples, with statistically significant differences primarily observed for carbon, while nitrogen showed no overall significant difference between drying methods. Chemical composition varied among clones, although no single clone consistently dominated across all chemical parameters. In contrast, pronounced tissue-type differences were observed: bark had higher nitrogen, carbon, sulfur, chlorine, and ash contents, whereas wood exhibited relatively higher hydrogen concentrations, with twigs showing intermediate values. These findings suggest that accounting for tissue-specific chemical differences can improve the selection and utilization of willow biomass and increase the accuracy of ecological assessments, including carbon storage estimates. The findings of this study indicate that oven-drying should remain in use within the bioenergy sector, whereas freeze-drying ought to become the preferred standard for carbon-accounting protocols. Full article

This paper presents an experimental investigation of hydrogen enrichment effects on combustion behavior and exhaust emissions in a self-developed micro gas turbine fueled with a propane–butane mixture. Hydrogen was blended with the base fuel in volume fractions of 0–30%, and combustion was examined under unloaded operating conditions at three global equivalence ratios (ϕ = 0.7, 1.1, and 1.3). The global equivalence ratio (ϕ) is defined as the ratio of the actual fuel–air ratio to the corresponding stoichiometric fuel–air ratio, with ϕ < 1 representing lean, ϕ = 1 stoichiometric, and ϕ > 1 fuel-rich operating conditions. The micro gas turbine is based on an automotive turbocharger coupled with a custom-designed counterflow combustion chamber developed specifically for alternative gaseous fuel research. Exhaust gas emissions of CO, CO₂, and NO_x were measured using a laboratory-grade FTIR analyzer (Horiba Mexa FTIR Horiba Ltd., Kyoto, Japan), while combustion chamber temperature was monitored with thermocouples. The results show that hydrogen addition significantly influences flame stability, combustion temperature, and emission characteristics. Increasing the hydrogen fraction led to a pronounced reduction in CO emissions across all equivalence ratios, indicating enhanced oxidation kinetics and improved combustion completeness. CO₂ concentrations decreased monotonically with hydrogen enrichment due to the reduced carbon content of the blended fuel and the shift of combustion products toward higher H₂O fractions. In contrast, NO_x emissions increased with increasing hydrogen content for all tested equivalence ratios, which is attributed to elevated local flame temperatures, enhanced reaction rates, and the formation of locally near-stoichiometric zones in the compact combustor. A slight reduction in NO_x at low hydrogen fractions was observed under near-stoichiometric conditions, suggesting a temporary shift toward a more distributed combustion regime. Overall, the findings demonstrate that hydrogen–propane–butane blends can be stably combusted in a micro gas turbine without major operational issues under unloaded conditions. While hydrogen addition offers clear benefits in terms of CO reduction and carbon-related emissions, effective NO_x mitigation strategies will be essential for future high-hydrogen microturbine applications. Full article

The transplanted cotton–wheat rotation enables dual cropping but alters root system architecture, typically suppressing taproot growth and promoting shallow lateral and fibrous roots, with unclear implications for irrigation response and water use efficiency (WUE). Field experiments were conducted in 2021 and 2022 to investigate root growth, spatial distribution, and water uptake sources, using a minirhizotron system and stable hydrogen and oxygen isotopes. The study examined the effects of two cultivation modes (direct seeding and transplanting) and three irrigation methods (border irrigation, micro-spray tape irrigation, and surface drip irrigation) on cotton root traits and WUE. Results showed that transplanted cotton roots were predominantly concentrated in the 0–30 cm soil layer (75.35–77.13% of total root length), significantly higher than those of direct-seeded cotton (63.10–74.71%). Under micro-spray tape and drip irrigation, the root length density (RLD) of transplanted cotton was 18.55% and 23.46% higher, respectively, than that of direct-seeded cotton, whereas under border irrigation it was 5.09% lower. Transplanted cotton mainly extracted water from the 0–40 cm soil layer (utilization rate: 65.49%), while direct-seeded cotton primarily relied on water from the 20–60 cm layer (53.20%). Although no statistically significant difference in yield was observed between the two cultivation modes, transplanted cotton exhibited a 15.37% higher WUE than direct-seeded cotton. Moreover, surface drip irrigation substantially enhanced WUE, exceeding that under border irrigation and micro-spray tape irrigation by 37.35% and 14.07%, respectively. This study enhances understanding of root traits in transplanted cotton and demonstrates that irrigation methods regulate WUE by modifying root distribution and water uptake patterns. Full article

A plasma-assisted ammonia jet flame igniter was developed in this study to address the limitations of conventional spark ignition at high pressures. The effect of pressure on plasma discharge characteristics, optical emission spectra, and exhaust gas emission was systematically investigated, providing new insights into the mechanisms of plasma-assisted ammonia ignition under high-pressure conditions. The results indicate that increased chamber pressure elevates gas density, which in turn raises the voltage required to sustain an arc discharge at 0.4 MPa and markedly reduces the frequency of arc drift. Spectral analysis shows that higher pressure inhibits atomic oxygen lines (777.2 nm and 844.6 nm) while intensifying the molecular nitrogen bands between 350–450 nm. A corresponding decrease in electron excitation temperature is also observed. In terms of exhaust composition, hydrogen concentration demonstrates a bifurcated behavior, rising with pressure under fuel-rich conditions (the equivalence ratio φ > 1.2) and falling under fuel-lean conditions (φ ≤ 1). Conversely, NO concentration consistently decreases with increasing pressure across all test conditions. The ammonia concentration in the exhaust gas shows opposite pressure dependencies at different equivalence ratios. It increases with rising pressure for φ ≥ 1, while it decreases with increasing pressure for φ < 1. Full article

Critical mineral supply chains underpin electric mobility, power electronics, clean hydrogen, and advanced manufacturing. Drawing on the resource-based view (RBV), the relational view, and dynamic capabilities, we conceptualize advantage not as ownership of ore bodies but as orchestration of multi-tier resource systems: upstream access, midstream processing know-how, standards and permits, and durable inter-organizational ties. In a world of high concentration at key stages (refining, separation, engineered materials), full “decoupling” is economically costly and technologically constraining. We argue for structured cooperation among the United States, European Union, China, and other producers and consumers, combined with selective domestic capability building for bona fide security needs. Methodologically, we conduct a structured conceptual synthesis integrating RBV, relational view, dynamic capabilities, and network-of-network research, combined with a structured comparative policy analysis of U.S./EU/Chinese instruments anchored in official documents. We operationalize the argument via technology–material dependency maps that identify midstream bottlenecks and the policy/standard levers most likely to expand qualified, compliant capacity. Full article

Rubber materials undergo continuous wear in high-pressure seal applications. To address the risk of adhesive wear and consequent leakage of rubber seals operating under reciprocating sliding in high-pressure hydrogen storage and refueling systems, this study employed high-pressure hydrogen tribology testing. Ball-on-disk reciprocating tests were conducted using a 316L stainless-steel ball against silica-filled nitrile butadiene rubber (NBR), and the friction response and wear-morphology evolution were compared under ambient air, 1 MPa hydrogen (H₂), 50 MPa H₂, 50 MPa nitrogen (N₂), and grease-coated conditions. Under dry sliding, the coefficient of friction (COF) of NBR in air and hydrogen ranged from 1.34 to 1.44, whereas it decreased markedly to 0.942 in 50 MPa N₂. The wear volume under the four dry conditions was concentrated in the range of ~0.292–0.320 mm³. After grease coating, the steady-state COF in air and at 50 MPa H₂ dropped to 0.099 and 0.105, respectively, and the wear features changed from ridge-like wear patterns/tear pits to regular, smooth indentations with slight running marks. The results demonstrate that a lubricating film can effectively separate direct metal–rubber contact and suppress stick–slip, enabling a low-friction, low-wear, and highly stable interface in high-pressure hydrogen, and providing a practical engineering route for reliable operation of rubber seals in hydrogen service. Full article

Many confined-space accidents have happened in wastewater treatment tanks, mainly caused by hazard gases. To identify the factors affecting the distribution of toxic and harmful gases in wastewater treatment tanks, in this study, we collected data on confined-space accidents occurring in wastewater treatment tanks in China and analyzed accident types, the substances that caused the accidents and the purpose of entry. We carried out field tests to detect the concentrations of oxygen, hydrogen sulfide, combustible gas and carbon monoxide in 222 wastewater treatment tanks from 28 industrial enterprises and investigated the influence of wastewater treatment tank type, cover type and industry type on gas distribution. Through continuous monitoring, the concentrations of hydrogen sulfide and carbon monoxide in the regulating tanks of two industrial enterprises were monitored for a few days. The mechanism of harmful gas generation and control approaches were explored and analyzed. The results showed that more than 90% of confined-space accidents in wastewater treatment tanks were poisoning accidents, and the levels of harmful gas in wastewater collection tanks, regulating tanks, hydrolysis acidification tanks, sedimentation tanks and sludge tanks were high, qualifying them as high-risk wastewater treatment tanks prone to accidents. Without disturbance, there is basically no harmful gas in wastewater treatment tanks with completely uncovered tops. In addition, the concentration of toxic and hazardous gases in wastewater treatment tanks is not always stable, instead fluctuating greatly with time. The main purposes of this study are to identify the factors affecting the concentration of toxic and harmful gases in wastewater treatment tanks and to assess the risks of using wastewater treatment tanks. Full article

Cyanobacteria, particularly Microcystis aeruginosa, can form dense blooms that impair water quality, and conventional treatment methods often fail to remove them effectively. This study evaluated the impact of cell age on the performance of the UV/H₂O₂ advanced oxidation process against M. aeruginosa. Cultures of M. aeruginosa were monitored over 64 days at an initial culture density of 1.20 × 10⁶ cells mL⁻¹. For the UV/H₂O₂ experiments, cells were adjusted to a density of 5.00 × 10⁵ cells mL⁻¹, and the growth and oxidative experiments were monitored using parameters such as hydrogen peroxide decay concentration, optical density at 730 nm (OD₇₃₀), cell density, and dissolved organic carbon (DOC). The hydrogen peroxide (H₂O₂) dosages used were 20 mg L⁻¹ and 50 mg L⁻¹, and the results showed that despite varying cell ages, H₂O₂ consumption remained stable at both dosages. While optical density and cell count indicate total cell removal, DOC levels increased due to cell lysis, resulting in contributions from both intracellular and extracellular fractions. A linear correlation was found between cell density and OD₇₃₀, and between total DOC and cell density. In conclusion, cell age did not influence the effectiveness of the UV/H₂O₂ process under the conditions tested. These findings indicate that UV/H₂O₂ can be an effective approach for managing cyanobacterial blooms in water treatment systems, with its performance being unaffected by cell age. Full article

Tylorrhynchus heterochaetus is an aquatic food with both edible and medicinal value in China. With a protein-rich body wall, it has strong potential for producing bioactive peptides. To explore its potential as a source of immunomodulatory peptides, in this study, flavor enzymes were selected as the optimal hydrolases, and the hydrolyzed products were subjected to ultrafiltration fractionation. The <3000 Da portion exhibited the most effective immune-stimulating activity in RAW 264.7 macrophages, enhancing phagocytosis and promoting the secretion of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and nitric oxide (NO) in a concentration dependent manner. Peptide omics analysis, combined with the activity and safety screened by bioinformatics, identified 43 candidate peptides. Molecular docking predicts that three novel peptides, LPWDPL, DDFVFLR and LPVGPLFN, exhibit strong binding affinity with toll-like receptor 4/myeloid differentiation factor-2 (TLR4/MD-2) receptors through hydrogen bonding and hydrophobic/π stacking interactions. Synthetic verification confirmed that these peptides were not only non-toxic to cells at concentrations ranging from 62.5 to 1000 µg/mL, but also effective in activating macrophages and stimulating the release of immune mediators. This study successfully identified the specific immunomodulatory peptides of the Tylorrhynchus heterochaetus, supporting its high-value utilization as a natural source of raw materials for immunomodulatory functional foods. Full article