Customized Utilization Strategies of Industrial Lignin to Produce Adsorbents and Flocculants Based on Fractionation and Adequate Structural Interpretation.

Lignin, a by-product of pulping and biorefinery, has great potential to replace petrochemical resources for wastewater purification. However, the defects of lignin, such as severe heterogeneity, inferior reactivity and poor solubility, characterize the production process of lignin-based products by high energy consumption and serious pollution. In this study, several lignin fractions with relatively homogeneous structure were first obtained by organic solvent fractionation, and their structures were fully deciphered by various characterization techniques. Subsequently, each lignin component was custom-valued for wastewater purification based on their structural characteristics. Benefiting from the high reactivity and reaction accessibility, the lignin fraction (lignin-1) refined by dissolving in ethanol and n-butanol could been used as a raw material to produce cationic lignin-based flocculant (LBF) in a copolymerization system using green, cheap and recyclable ethanol as solvent. The lignin fraction (lignin-2) extracted by methanol and dioxane showed low reactivity and high carbon content, which was used to produce lignin-based activated carbon (LAC) with phosphoric acid as activator. Moreover, the influences of synthetic factors on the purification capacity were discussed, and the LBF and LAC produced under the optimal conditions showed distinguished purification effect on kaolin suspension and heavy metal wastewater, respectively. Furthermore, the corresponding purification mechanism and external factors were also elaborated. It is believed that this cleaner production strategy is helpful for the valorization of lignin in wastewater resources.

Effect of Ultrasonic Irrigation Combined with Epoxy Resin Paste in Single Visit Root Canal Treatment in Chronic Pulpitis.

OBJECTIVE: To determine the clinical efficacy of ultrasonic irrigation combined with epoxy resin-based sealer in single visit root canal treatment of chronic pulpitis. STUDY DESIGN: Randomised controlled trial. Place and Duration of the Study: Department of Stomatology, Hefei BOE Hospital, Hefei, China, from March 2019 to December 2021. METHODOLOGY: Ninety patients with chronic pulpitis, comprising 104 affected teeth, were enrolled. Using a random number table, they were divided into Group A (n = 30, 35 teeth), Group B (n = 30, 35 teeth), and the control group (n = 30, 34 teeth). All underwent single visit root canal treatment. Group A received ultrasonic irrigation followed by sealing with epoxy resin-based paste; Group B had conventional syringe irrigation followed by the same sealing; the control group had syringe irrigation and closure with zinc oxide-eugenol paste. Pain during treatment, posttreatment clinical outcomes, and differences in inflammatory markers (IL-4, IL-6, hs-CRP), and quality of life (QOL) scores pre- and posttreatment over two months were observed. RESULTS: After the treatment, improvement rates for Groups A, B, and the control group were 91.4%, 65.7%, and 61.7%, respectively. Pain occurrence rates were 6.7%, 30.0%, and 36.7%, respectively. Group A outperformed both Group B and the control group in improvement and pain incidence with statistical significance (p<0.016). Posttreatment, Group A had lower IL-4, IL-6, hs-CRP levels than Groups B and the control group (p<0.05), and had higher scores for sleep, mood, and appetite (p<0.05). CONCLUSION: Ultrasonic irrigation combined with epoxy resin-based paste yields better results for chronic pulpitis treatment, reducing postoperative pain, mitigating inflammation levels, and enhancing quality of life. KEY WORDS: Chronic pulpitis, Ultrasonic irrigation, Epoxy resin paste, Root canal treatment, Therapeutic effect.

Emerging chitin nanogels/rectorite nanocomposites for safe and effective hemorrhage control.

Excessive bleeding due to trauma, surgery and diseases may cause severe mortalities. Here, an emerging chitin nanogel/rectorite nanocomposite is developed for effective hemorrhage control. Chitin chains are intercalated into rectorite and subsequent mechanical high speed stirring generates chitin nanogels, which assemble on the surface of the rectorite nanoplates through electrostatic interactions to form a sandwich structure. The in vitro experiments reveal that the nanocomposite exhibits favorable biocompatibility and negligible hemolysis (<3.5%) as compared to rectorite (40%). The nanocomposite stops bleeding in 121 s in rat tail incision and exhibits higher hemostatic activity in the rabbit artery injury model as compared to a commercialized chitosan hemostat, Celox. The efficient blood clotting activity is attributed to the induction of a coagulation cascade by rectorite and the quick adsorption and aggregation of platelets and red blood cells by chitin. The enhanced biocompatibility and hemostatic activity of the chitin/rectorite nanocomposite make it a safe and cost effective hemostat to control bleeding.

A simple mechanical agitation method to fabricate chitin nanogels directly from chitin solution and subsequent surface modification.

The development of physical approaches and green technologies to construct novel chitin materials is essential for the exquisite utilization of the renewable and valuable resource of chitin. In the present study, chitin nanogels were simply fabricated from a chitin solution dissolved in 8% NaOH/4% urea aqueous solvent by high speed stirring. The mechanical stirring generated in situ heat that induced the regeneration of chitin chains and ensured good dispersion of the nanogels. The prepared nanogels were composed of spherical nanoparticles of size 20 to 30 nm with some aggregates. The formation of chitin nanogels was confirmed to be a physical process without using organic solvent or chemical crosslinking. Rheological tests revealed a shear thinning behavior of the nanogels and injectable hydrogels were developed accordingly. The chitin nanogels showed no toxicity to L929 cells and cell attachment on the surface of the nanogel was observed. Further, monodispersed cationic nanogels and anionic nanogels were facilely obtained by deacetylating and TEMPO-mediated oxidizing chitin nanogels, and demonstrated different antibacterial properties.

[Influence of mobile phase composition on chiral separation of organic selenium racemates].

The chiral separation of some chiral compounds with similar structure on the cellulose tris (3,5-dimethylphenylcarbamate) chiral stationary phase prepared by us was obtained. Ternary mobile phases influencing chiral recognition were investigated. A mode of interaction between the structural character of samples and chiral stationary phase is discussed. The results indicated that the retention and chiral separation of the analytes had a bigger change with minute addition of alcohols or acetonitrile as modifier in n-hexane/2-propanol (80/20, volume ratio) binary mobile phase.