Faster Degradation Rate Research Articles

Boosting Reactive Oxygen Species Generation via Contact‐Electro‐Catalysis with FeIII‐Initiated Self‐cycled Fenton System

AbstractContact Electro‐Catalysis (CEC) using commercial dielectric materials in contact‐separation cycles with water can trigger interfacial electron transfer and induce the generation of reactive oxygen species (ROS). However, the inherent hydrophobicity of commercial dielectric materials limits the effective reaction sites, and the generated ROS inevitably undergo self‐combination to form hydrogen peroxide (H2O2). In typical CEC systems, H2O2 does not further decompose into ROS, leading to suboptimal reaction rates. Addressing the generation and activation of H2O2 is therefore crucial for advancing CEC. Here, we synthesized a catalyst by loading the dielectric material polytetrafluoroethylene (PTFE) onto ZSM‐5 (PTFE/ZSM‐5, PZ for short), achieving uniform dispersion of the catalyst in water for the first time. The introduction of an FeIII‐initiated self‐cycling Fenton system (SF‐CEC), with the synergistic effects of O2 activation and FeIII‐activated H2O2, further enhanced ROS generation. In the FeIII‐initiated SF‐CEC system, the synergistic effects of ROS and protonated azo dyes enabled nearly 99 % degradation of azo dyes within 10 minutes, a sixfold improvement compared to the CEC system. This represents the fastest degradation rate of methyl orange dye induced by ultrasound to date. Without extra oxidants, this system enabled stable dissolution of precious metals in weakly acidic solutions at room temperature, achieving 80 % gold dissolution within 2 hours, 2.5 times faster than similar CEC systems. This study also corrects the unfavorable perception of CEC applications under acidic conditions, providing new insights for the fields of dye degradation and precious metal recovery.

Effect of carbodiimides on the compatibility and hydrolytic behavior of PLA/PBAT blends

Blends of polylactic acid (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) have great potential to replace conventional polyolefin and polyester materials. However, poor compatibility and fast degradation rate limit its development. In this paper, the effects of two monomer-type carbodiimides and one polymerized carbodiimide on the crystalline, thermal stability, hydrolysis properties, and mechanical properties of PLA/PBAT blends are investigated by Fourier transform infrared spectroscopy, scanning electron microscope, differential scanning calorimetry, thermogravimetric analysis, gel permeation chromatography, melt mass-flow rate, terminal carboxyl content, tensile properties, and rotational torque. It is found that all the three carbodiimide additives can improve the compatibility and enhance the mechanical, processing, and thermal stability properties of PLA/PBAT blends except for their reduced crystallization performance. Moreover, regarding the hydrolysis properties, the two monomeric carbodiimides exhibit little effect on the hydrolysis of PLA/PBAT blends, even accelerating the degradation rate under alkaline conditions. However, the antihydrolysis effect of polycarbodiimide is remarkable, which effectively improves the compatibility and antihydrolysis properties of PLA/PBAT blends.

In Situ Driven Formation of Anatase/Brookite/Rutile Heterojunction N/TiO2 Nanocrystals as Sustainable Visible-Light Catalysts.

Visible-light active anatase/brookite/rutile (A/B/R) ternary N-doped titania (N/TiO2) crystals are successfully prepared by a facile sol-gel method using titanium butoxide and benign N-dopant source, guanidinium chloride. Systematically varying the aging time (1, 4, 8, and 12 d), its influence on physicochemical properties of as-obtained spherical heterojunction nanomaterials is studied. Detailed characterizations confirm that a substantial amount of anatase (88% to 50%) is transformed to rutile (2% to 38%) via intermediate brookite phase (9% to 25%) as the function of aging time; not only the A/B/R phase content of the samples is tuned by sol-gel aging time of the precursors solution but also their optical-response and methylene blue photocatalytic properties are profoundly dictated. Notably under visible-light irradiation, the photostable rutile rich mesoporous A/B/R triphasic N/TiO2 (50% A, 12% B, 38% R) aged for 12 d demonstrates higher degradation activity (97%) with a faster degradation rate (0.033 min-1) than both lesser aged N/TiO2 and undoped titania. This enhancement is attributed to the synergistic effect of interstitial-N-doping and optimal A/B/R interfacial charge transfer that leads to higher light absorption, lower bandgap energy and well-separated charge carriers. The current work provides a new perspective for designing highly active visible-light heterostructure nanomaterials with controllable phase composition.

Recent replenishment of aliphatic organics on Ceres from a large subsurface reservoir.

Ceres hosts notable aliphatic-organic concentrations, ranging from approximately 5 to >30 weight % in specific surface areas. The origins and persistence of these organics are under debate due to the intense aliphatic organic signature and radiation levels in Ceres' orbit, which would typically lead to their destruction, hindering detection. To investigate this, we conducted laboratory experiments to replicate how the signature of the organic-rich regions would degrade due to radiation. Our findings indicate a fast degradation rate, implying the exposure of buried organics within the past few million years. This degradation rate, coupled with observed quantities, implies that the aliphatics must be present in substantial quantities within the shallow subsurface. Our estimates suggest an initial aliphatic abundance 2 to 30 times greater than currently observed, surpassing significantly the levels found in carbonaceous chondrites, indicating either a significant concentration or remarkable purity.

Structure‐Controlled Interpenetrated MOF@COF via C−C Linkage for Enhanced Photocatalysis

AbstractDiversifying the connecting junctions will be feasible for the controllable collaboration of metal–organic frameworks (MOFs) and covalent organic frameworks (COFs) to rationally design multifunction‐integrated heterostructures with enhanced performance, yet it is in the nascent stage. Herein, by intelligently exploiting the polymerization of vinyl group, C−C bond is innovatively introduced to construct the core–shell MOF@COF heterostructures with adjustable shell thickness and rare interpenetrated structure. The unique structure endows prepared C−C‐linked MIL‐68@COF−Vs with more superior visible‐light harvesting and photogenerated carrier separation capability, leading to significantly higher photocatalytic activity and faster degradation rate than pristine MIL‐68‐C=Cs, COF−V, and imine‐linked MIL‐68‐NH2@COF−V. Further, the customized MIL‐68@COF−V is in situ grown as reusable films with dramatically boosted performance under ambient conditions, which realize the highly efficient degradation of tetracycline within 15 min (96.5 %), rhodamine 6G within 25 min (97.6 %), and phenol within 40 min (95.3 %) by solar drive. This work exhibits the distinctive advantages of C−C junction in the MOF@COF construction, and highlights the application prospect of rational‐designed heterostructure in the treatment of persistent organic pollutants.

Structure-Controlled Interpenetrated MOF@COF via C-C Linkage for Enhanced Photocatalysis.

Diversifying the connecting junctions will be feasible for the controllable collaboration of metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) to rationally design multifunction-integrated heterostructures with enhanced performance, yet it is in the nascent stage. Herein, by intelligently exploiting the polymerization of vinyl group, C-C bond is innovatively introduced to construct the core-shell MOF@COF heterostructures with adjustable shell thickness and rare interpenetrated structure. The unique structure endows prepared C-C-linked MIL-68@COF-Vs with more superior visible-light harvesting and photogenerated carrier separation capability, leading to significantly higher photocatalytic activity and faster degradation rate than pristine MIL-68-C=Cs, COF-V, and imine-linked MIL-68-NH2@COF-V. Further, the customized MIL-68@COF-V is in situ grown as reusable films with dramatically boosted performance under ambient conditions, which realize the highly efficient degradation of tetracycline within 15 min (96.5 %), rhodamine 6G within 25 min (97.6 %), and phenol within 40 min (95.3 %) by solar drive. This work exhibits the distinctive advantages of C-C junction in the MOF@COF construction, and highlights the application prospect of rational-designed heterostructure in the treatment of persistent organic pollutants.

Fabrication of small-diameter in situ tissue engineered vascular grafts with core/shell fibrous structure and a one-year evaluation via rat abdominal vessel replacement model

A high vascular patency was realized in the bulk or surface heparinized small-diameter in situ tissue-engineered vascular grafts (TEVGs) via a rabbit carotid artery replacement model in our previous studies. Those surface heparinized TEVGs could reduce the occurrence of aneurysms, but with a low level of the remodeled elastin, whereas those bulk heparinized TEVGs displayed a faster degradation and an increasing occurrence of aneurysms, but with a high level of the regenerated elastin. To combine the advantages of the bulk and surface graft heparinization to boost the remodeling of elastin and defer the occurrence of aneurysms, a coaxial electro-spinning technique was used to fabricate a kind of small-diameter core/shell fibrous structural in situ TEVGs with a faster degradable poly(lactic-co-glycolic acid) (PLGA) as a core layer and a relatively lower degradable poly(ε-caprolactone) (PCL) as a shell layer followed by the surface heparinization. The in vitro mechanical performance and enzymatic degradation tests revealed the resulting PLGA@PCL-Hep in situ TEVGs possessing not only a faster degradation rate, but also the mechanical properties comparable to those of human saphenous veins. After implanted in the rat abdominal aorta for 12 months, the good endothelialization, low inflammation, and no calcification were evidenced. Furthermore, the neointima layer of regenerated new blood vessels was basically constructed with a well-organized arrangement of elastin and collagen proteins. The results showed the great potential of these in situ TEVGs to be used as a novel type of long-term small-diameter vascular grafts.

Effect of the Addition of Inorganic Fillers on the Properties of Degradable Polymeric Blends for Bone Tissue Engineering.

Bone tissue exhibits self-healing properties; however, not all defects can be repaired without surgical intervention. Bone tissue engineering offers artificial scaffolds, which can act as a temporary matrix for bone regeneration. The aim of this study was to manufacture scaffolds made of poly(lactic acid), poly(ε-caprolactone), poly(propylene fumarate), and poly(ethylene glycol) modified with bioglass, beta tricalcium phosphate (TCP), and/or wollastonite (W) particles. The scaffolds were fabricated using a gel-casting method and observed with optical and scanning electron microscopes. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR), differential scanning calorimetry (DSC), thermogravimetry (TG), wettability, and degradation tests were conducted. The highest content of TCP without W in the composition caused the highest hydrophilicity (water contact angle of 61.9 ± 6.3°), the fastest degradation rate (7% mass loss within 28 days), moderate ability to precipitate CaP after incubation in PBS, and no cytotoxicity for L929 cells. The highest content of W without TCP caused the highest hydrophobicity (water contact angle of 83.4 ± 1.7°), the lowest thermal stability, slower degradation (3% mass loss within 28 days), and did not evoke CaP precipitation. Moreover, some signs of cytotoxicity on day 1 were observed. The samples with both TCP and W showed moderate properties and the best cytocompatibility on day 4. Interestingly, they were covered with typical cauliflower-like hydroxyapatite deposits after incubation in phosphate-buffered saline (PBS), which might be a sign of their excellent bioactivity.

(Invited) Low Cost in Situ Electrosynthesis and Cycling of Quinone Negolytes in a Commercial Flow Battery Stack

Aqueous organic redox flow batteries (RFBs) potentially offer greatly lower capital cost relative to vanadium RFBs or even lithium-ion batteries, as they use no critical materials and are instead derived from very inexpensive precursors. To date, the success of organic RFBs as a whole has been hampered by two factors. The first is the high cost of scaling up a new chemistry, as every synthetic step adds cost and complexity and creates waste that must be disposed of. The second is fast degradation of the reactants and has been largely mitigated through various strategies that have recently been reported. The recent results mean that low-cost compounds that may intrinsically have a fast degradation rate, now merit consideration since their fade rate can be lowered significantly.We report the development of an in situ electrosynthesis process, from the lab scale to the ton scale, that creates the organic RFB negolyte from the starting reactants using commercial RFB stacks that have been repurposed as chemical reactors. The yield and purity are even higher than the equivalent chemical process and no further purification or downstream processing is required; the entire process is self-contained and produces zero waste which greatly simplifies scaleup, permitting, and implementation. Moreover, the as-produced material can be immediately cycled as a drop-in replacement for vanadium in RFBs with minimal modification of existing vanadium RFB designs.This unique in situ strategy enables rapid scaling of a new chemistry in a way that supports local manufacture, which is of strategic importance to many governments. Further cost reductions are envisioned if it can be implemented at the customer site -- inside a completed flow battery system -- rather than at a centralized facility.When combined with previous results on reversing the degradation of quinone RFB reactants, the electrosynthetic pathway to producing organic RFB negolytes is the final missing piece of the puzzle in the commercialization of an affordable, practical, and viable organic RFB chemistry.

Contact-Electro-Catalysis Through Electret Behavior to Facilitate Electron Transfer.

Contact-electro-catalysis (CEC) usually uses polymer dielectrics as its catalysts under mechanical stimulation conditions, which although has a decent catalytic dye degradation effect still warrants performance improvement. A carrier separation promotion strategy based on an internal electric field by polarization can effectively improve ferroelectric material performance in photocatalysis and piezocatalysis. Therefore, carrier separation as a necessary process of CEC also can be promoted and is largely expected to improve CEC performance theoretically. However, the carrier separation enhancement by the internal electric field strategy has not been achieved in the CEC experiment yet, because of the difficulty of building an internal electric field in an inert polymer dielectric. Herein, a polytetrafluoroethylene (PTFE) dielectric was charged through an electret process, which was believed to establish an internal electric field for CEC catalysts proved by KPFM, XPS, and triboelectric nanogenerator voltage output analysis. The fastest degradation rate of methyl orange reached over 90% at 1.5 h, while the hydroxyl free radical (•OH) yield of the PTFE electret was nearly three times that of the original PTFE. Density functional theory (DFT) calculations verified that the potential barrier of interatomic electron transfer between PTFE and H2O was reduced by 37% under the internal electric field. The electret strategy used herein to optimize the PTFE catalyst provides a base for the use of other general plastics in CEC and facilitates the production of easily prepared, easily recyclable, and inexpensive polymer dielectric catalysts that can promote large-scale pollutant degradation via CEC.

Trypsin-encoding gene function of efficient star polycation nanomaterial-mediated dsRNA feeding delivery system of Grapholita molesta.

Grapholita molesta is an important and harmful fruit pest worldwide, with widespread feeding hosts. Trypsin, an indispensable hydrolytic digestive protease in the insect gut, is crucial in digestion, growth and development. We analyzed the characteristics of the trypsin-encoding genes, screened for the optimal dose of RNAi mediated by nanocarriers, and investigated various indices of larval growth and development of G. molesta. Gut content (GC) and RNase A degraded double-stranded RNA (dsRNA), with a faster degradation rate at higher concentrations. Star polycation (SPc) nanomaterials protected dsGFP from degradation by anion-cation binding and did not migrate through agarose gel. The key conserved motifs of the trypsin-encoding genes were similar, exhibiting high homology with those in other lepidopteran insects. An interference efficiency of ≈70% was achieved with SPc nanomaterial-mediated RNA interference with 0.05 μg dsRNA. The efficiency of continuous interference was stable. Trypsin activity, body weight of 8-day-old larvae, pupal weight and emergence rate were significantly reduced, and the larval stage was significantly prolonged. The investigated trypsin gene is a key target gene in the growth and development of G. molesta. We investigated the efficiency and convenience of feeding SPc nanomaterials in a functional study of insects. Our results provide valuable data for the development of efficient trypsin-targeting pesticides. © 2024 Society of Chemical Industry.

Photodegradation of bisphenol A (BPA) in coastal aquaculture waters: Influencing factors, products, and pathways

Bisphenol A (BPA), an endocrine-disrupting contaminant, is ubiquitous in the environment due to its presence in plastics, wastewater, and agricultural runoff. This study investigated the photodegradation behavior of BPA in coastal aquaculture waters near Qingdao, China. Lower salinity promoted BPA photodegradation, while higher salinity has an inhibitory effect, suggesting slower degradation in seawater compared to ultrapure water. Triplet-excited dissolved organic matter (3DOM*) was identified as the primary mediator of BPA degradation, with additional contributions from hydroxyl radicals (•OH), singlet oxygen (1O2), and halogen radicals (HRS). Alepocephalidae aquaculture water exhibited the fastest degradation rate, likely due to its high DOM and nitrate/nitrite (NO3−/NO2−) content, which are sources of 3DOM* and •OH. A positive correlation existed between NO3−/NO2− concentration and the BPA degradation rate. Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) analysis identified the primary BPA photodegradation products, formed mainly through oxidative degradation, hydroxyl substitution, nitration, and chlorination pathways. Elucidating these photodegradation mechanisms provides valuable insights into the environmental fate and potential ecological risks of BPA in aquaculture environments. This knowledge can inform strategies for marine environmental protection and the development of sustainable practices.

Efficient adsorption and rapid electrochemical degradation of methyl methacrylate (MMA) by three-dimensional nanostructured carbon anode

Methyl methacrylate (MMA) is a widely used oxygen-containing volatile organic compound, functioning as both an organic solvent and additive. Therefore, the advancement of effective methods for MMA removal is of great significance. In this study, three-dimensional nanostructured carbon (CNTs/CC) anode materials were prepared through the in-situ growth of carbon nanotubes (CNTs) on carbon cloth (CC) using chemical vapor deposition (CVD). The prepared material showed outstanding adsorption-electrocatalytic degradation performance towards MMA, with a saturated adsorption capacity of 2033 mg·g−1 and complete degradation achieved after 90 min of electrification at a 100 mg·L−1 MMA concentration. The electrochemically active surface area increased to 29.8 cm2 with an Rs value of 2.35 Ω for the CNTs/CC-2 anode material, leading to enhanced ·OH generation capability and faster degradation rates. The material also exhibited excellent reusability over thirteen cycles of adsorption-electrochemical degradation of MMA, with a degradation efficiency consistently above 92 %. This research provides valuable insights for developing new materials and technologies for MMA degradation.

Use of Polylactic Acid Added with Calcium Oxide and 3-Iodo-2-Propynly Butyl Carbamate as an Antifungal Agent and Bio-degradable Soil Remediator

This work studied the use of polylactic acid added with calcium oxide (CaO) and 3-Iodo-2-propynly butyl carbamate (IPBC) for agricultural applications. CaO content of 30 pph was fixed, while IPBC contents were varied at 0, 2.5, 5.0, 7.5 and 10.0 ppm in the polymer matrix. All ingredients were mixed by the extrusion process for receiving the PLA, PLA/CaO, and PLA/CaO/IPBC granules. The pH value, antifungal activities of Phytophthora parasitica, tomato growth, and disposal degradation were also investigated. The experimental results indicated that the acidic condition of the PLA granules increased with increasing IPBC contents but was compromised by CaO. An IPBC was an effective antifungal agent. It was also promoted and activated by CaO. Growth of P. parasitica can be inhibited by CaO synergized IPBC for the PLA/CaO granules with four different IPBC contents and the PLA/CaO granules with the four different IPBC contents were an effective antifungal agent. A PLA/CaO granule with an IPBC content of 2.5 ppm can be developed to compete with an unused condition. A PLA/CaO granule with an IPBC content of 10 ppm was recommended for agricultural applications. A PLA/CaO/IPBC 10 acted as an effective antifungal agent and compostable for soil bioremediatory before planting. Over the 45-day experimental period, the maximum percentage of weight loss of a PLA/CaO granule with an IPBC content of 10 ppm was influenced by moisture and initial PLA loading. A PLA/CaO granule with an IPBC content of 10 ppm (47.2%) had a faster degradation rate than a PLA/CaO granule (45.3%) and a neat PLA granule (15.0%).

Chronic kidney disease: a contraindication for using biodegradable magnesium or its alloys as potential orthopedic implants?

Magnesium (Mg) has gained widespread recognition as a potential revolutionary orthopedic biomaterial. However, whether the biodegradation of the Mg-based orthopedic implants would pose a risk to patients with chronic kidney disease (CKD) remains undetermined as the kidney is a key organ regulating mineral homeostasis. A rat CKD model was established by a 5/6 subtotal nephrectomy approach, followed by intramedullary implantation of three types of pins: stainless steel, high pure Mg with high corrosion resistance, and the Mg–Sr–Zn alloy with a fast degradation rate. The long-term biosafety of the biodegradable Mg or its alloys as orthopedic implants were systematically evaluated. During an experimental period of 12 weeks, the implantation did not result in a substantial rise of Mg ion concentration in serum or major organs such as hearts, livers, spleens, lungs, or kidneys. No pathological changes were observed in organs using various histological techniques. No significantly increased iNOS-positive cells or apoptotic cells in these organs were identified. The biodegradable Mg or its alloys as orthopedic implants did not pose an extra health risk to CKD rats at long-term follow-up, suggesting that these biodegradable orthopedic devices might be suitable for most target populations, including patients with CKD.

A study of biodegradation, water uptake and thickness swelling of animal fibers reinforced unsaturated polyester resin composites

The ever-increasing quantities of trash produced by the poultry and tannery industries, particularly chicken feathers, cow hairs, and waste leather fibers, pose serious challenges to maintaining a pristine natural environment. In this research, the polymer composites were produced by combining 2, 5, 7, 10, 12, and 15 % (by weight) recycled chicken feather fibers (CFF), cow hair fibers (CHF), and leather fibers (LF) with inorganic materials ZnO, Al2O3, CaCO3, and unsaturated polyester resin (UPR) through a hand lay-up process. After cleaning, a portion of the fibers was subjected to a two-hour soak in 0.20 M KOH at 50 °C, followed by five hours of drying at 60 °C, and the remaining half was not attended. This study successfully reduced environmentally hazardous waste from the poultry and tannery industries. The biodegradation of composites was compared in weather, water, brine, soil and compost over a period of 90 days at 25 °C, suggesting that the composites have potential in a variety of settings. Degradation rates varied among the composites, and the leather fibre-UPR composites (LR + UPR + Al2O3) showed the fastest degradation rate under all media and were especially degraded highest percentages (17.8 %) when buried in compost. Degradation percentages in compost media for (CHF + UPR + Al2O3), (CFF + UPR + Al2O3) and (CHF + CFF + UPR + Al2O3)) composites are 16.3 %, 14.8 %, and 13.5, respectively. The helical structure of the composites disintegrated in thermogravimetric analysis (TGA), losing its chain-linkage skeleton and peptide fiber bridges, and dissolving keratin and collagen into carbon dioxide (CO2), hydrogen sulfide (H2S), and hydrogen cyanide (HCN). The results of the water uptake and thickness swelling study for up to 15 days due to water absorption can have positive effects on the mechanical properties of the composite material and found 8.8 % water uptake and 15.8 % thickness swelling both for (LR + UPR + Al2O3) composite.

Gelatin-containing functionally graded calcium sulfate/bioactive glass bone tissue engineering scaffold

One of the challenges and limitations of bone tissue engineering includes fast degradation rates, reduced bioactivity, donor site morbidity, and unresolved risks of pathogen transmission. In the field of bone tissue engineering, gradient materials are promising for treating bone defects because they can create graded structures and compositions similar to natural bone. By controlling the amount of components in the structure, the degradation rate, bioactivity, and osteogenic capacity can be manipulated. In the current study, a gradient, multilayer, porous nanocomposite of calcium sulfate/glass (Gn CS/BG) with a gelatin coating (Gn CS/BG-Gel) was prepared using rotational casting technique. The SEM results showed an average pore size of approximately 400 μm within the Gn CS/BG-Gel nanocomposite. An elastic modulus (E) of around 240 MPa and an ultimate tensile strength (σ) of approximately 5.5 MPa were achieved for Gn CS/BG-Gel nanocomposite. The degradation analysis in a dynamic tris-buffer environment revealed a degradation rate of 68 % over a 63-day period, with a decrease in degradation rate as the bioactive glass (BG) content increased in each layer, indicating the influence of BG on the degradation process. The bioactivity results in a dynamic simulated body fluid suggested that increased BG content in each layer promoted hydroxyapatite formation, indicating improved bioactive behavior. The evaluation of ion release with ICP-OES, MTT and Acridine Orange assays using human bone marrow-derived mesenchymal stem cells (hBMSCs) confirmed the non-toxic nature of Gn CS/BG-Gel. Assessments of alkaline phosphatase (ALP) activity, calcium content, Alizarin Red staining and cell attachment behavior substantiated the osteogenic potential of Gn CS/BG-Gel. Collectively, the three-dimensional structure along with the Gn CS/BG-Gel composition contributed to the enhanced cellular responses. These findings hold significant promise for the development of biomaterials with potential applications in bone tissue engineering, and they contribute valuable insights to the field.

Preparation and application of curcumin loaded with citric acid crosslinked chitosan-gelatin hydrogels

While oral administration offers safety benefits, its therapeutic efficacy is hindered by various physiological factors within the body. In this study, a novel approach was explored using a matrix consisting of 2 % chitosan and 2 % gelatin, with citric acid (CA) serving as a green cross-linking agent (ranging from 0.4 % to 1.0 %), and curcumin (Cur) as the model drug to formulate hydrogel carriers. The results showed that a 0.4 % CA concentration, the hydrogel (CGA0.4) reached swelling equilibrium in deionized water within 40 min, exhibiting a maximum swelling index was 539 g/g. The addition of Cur to the CGA hydrogel (CGACur) notably enhanced release efficiency, particularly in simulated intestinal fluid, where Cur release rates exceeded 40 % within 100 min compared to below 8 % in other solutions. Among these hydrogels, CGA0.4Cur exhibited the fastest degradation rate in the combined solution, reaching >90 % degradation after 7 days. Additionally, Cur and CA demonstrated positive effects on the tensile strength, antioxidant activity and antibacterial activity of hydrogels. Compare to the bioaccessibility of CGC (27 %), those of CGACur had increased to over 34 %. These findings offer provide theoretical support for CA-crosslinked chitosan/gelatin gels in delivering hydrophobic bioactive molecules and their application in intestinal drug delivery system.

Effect of Silver Content and T4 Treatment on the In Vitro Degradation Behavior of Gasar Porous Mg–Ag Alloy

Mg–Ag alloy has potential as a material for bone tissue repair, but the faster degradation rate in vivo limits its use in medical applications. In this study, pure Mg and Mg99.5Ag0.5 alloy with a porous structure are prepared using the metal/gas eutectic unidirectional solidification method (Gasar process). The influence of introducing Ag on the degradation behavior of porous Mg99.5Ag0.5 and pure Mg is investigated. The addition of Ag increases the compressive strength and elastic modulus of the material. The corrosion resistance of as‐cast Mg99.5Ag0.5 alloy decreases due to localized aggregation of Ag in the alloys. Therefore, the T4 (solution treatment) is chosen for the Mg99.5Ag0.5 alloy. After T4 treatment, due to the uniform distribution of Ag atoms in the alloy, the corrosion behavior on the alloy surface is more uniform, and a denser Mg(OH)2 passivation layer is formed on the surface, which reduces the degradation rate of Mg99.5Ag0.5. Importantly, insoluble Ca–P compounds in the form of hydroxyapatite (HA) phases gradually grown on passivated layers of porous T4 Mg99.5Ag0.5 contribute to bone growth. This indicates the feasibility of using the T4 Gasar porous Mg99.5Ag0.5 alloy as a potential tissue engineering scaffold.

Progress of organic wastewater degradation by atmospheric pressure gliding arc plasma technology: A review

The prevention and treatment of organic pollutants in wastewater have attracted extensive attention because they threaten ecological balance and human health. Traditional wastewater treatment technologies, such as physical, chemical, biological methods, etc., are still limiting and challenging due to some factors, such as high energy consumption, chemical agents, low efficiency, and secondary pollution. At present, gliding arc plasma, based on equilibrium/non-equilibrium in plasma temperature, demonstrates itself to be one of the most promising technologies for the degradation of refractory organics with its fast degradation rates, no secondary contamination, high efficiency, and so on. The theoretical mechanisms and typical applications of gliding arc plasma degradation of wastewater are introduced in detail in this paper. The physical and chemical characteristics of gliding arc plasma and the role of the reactive species in the plasma are reviewed.