Degradable Vinyl Polymers for Combating Marine Biofouling.

Marine organisms such as barnacle larvae and spores of algae adhere to underwater surfaces leading to marine biofouling. This phenomenon has numerous adverse impacts on marine industries and maritime activities. Due to the diversity of fouling organisms and the complexity of the marine environment, it is a huge challenge to combat marine biofouling, which limits the development and utilization of marine resources. Since the International Marine Organization banned the use of tributyltin self-polishing copolymer (SPC) coatings in 2008, the development of an environmentally friendly and efficient anti-biofouling polymer has been the most important task in this field. Tin-free SPC is a well-established and widely used polymer binder for anti-biofouling coating today. Being a nondegradable vinyl polymer, SPC exhibits poor anti-biofouling performance in static conditions. Even more, such nondegradable polymers were considered to be a source of microplastics by the International Union for the Conservation of Nature in 2019. Recently, numerous degradable polymers, which can form dynamic surface through main chain scission, have been developed for preventing marine biofouling in static conditions. Nevertheless, the regulation of their degradation and mechanical properties is limited, and they are also difficult to functionalize. A new polymer combining the advantages of vinyl polymers and degradable polymers is needed. However, such a combination is a challenge since the former are synthesized via free radical polymerization whereas the latter are synthesized via ring-opening polymerization.In this Account, we review our recent progress toward degradable vinyl polymers for marine anti-biofouling in terms of polymerization methods and structures and properties of polymers. First, we introduce the strategies for preparing degradable vinyl polymers with an emphasis on hybrid copolymerization. Then, we present the synthesis and performance of degradable and hydrolyzable polyacrylates, degradable polyurethanes with hydrolyzable side groups, and surface-fragmenting hyperbranched polymers. Polymers with degradable main chains and hydrolyzable side groups combine the advantages of SPC and degradable polymers, so they are degradable and functional. They are becoming new-generation polymers with great potential for preparing high-efficiency, long-lasting, environmentally friendly and broad-spectrum coatings to inhibit marine biofouling. They can also find applications in wastewater treatment, biomedical materials, and other fields.

Human three-dimensional dental pulp organoid model for toxicity screening of dental materials on dental pulp cells and tissue.

AIM: To establish a 3D model for screening the biocompatibility of dental materials/drugs on dental pulp cells and tissue. METHODOLOGY: Human dental pulp cells (hDPC) and endothelial cells (EC) were mixed with or without human dental pulp derived extracellular matrix (hDP-ECM) according to several protocols and cultured in 3D plates to fabricate 3D organoids. Cell viability and proliferation in organoids were evaluated using Live/Dead cell viability assay and ATPase assay. Organoids were fixed, cut and stained with a H&E staining kit. The expressions of DSPP, DMP-1, CD31, vWF and COL1A in 3D organoids were evaluated using immunofluorescence. To assess the feasibility of 3D organoids on drug/material toxicity screening, the organoids were treated with lipopolysaccharides (LPS) or iRoot BP. Then, cell viability and apoptosis were assessed. The expressions of IL-6, TNF-α, and IL-1ß were compared in LPS-treated and non-treated organoids. Alizarin Red S staining was used to evaluate calcium deposit formation in organoids. Data were analysed using one-way anova followed by Tukey's post hoc comparison. RESULTS: The 3D spheres/organoids were formed at day 1 or day 2. Cells in 3D organoids maintained a high viability rate and low proliferation activity. The level of CD31 increased significantly (p < .05) when EC were added to coculture with hDPC. The expressions of odontogenesis-associated proteins (DSPP, COL1A) upregulated (p < .05) with the addition of hDP-ECM. Level of IL-6 expression and rates of dead and apoptotic cells in 3D organoids were increased significantly (p < .05) in response to LPS. Calcium deposit formation was observed in iRoot BP-treated organoids. CONCLUSIONS: Coculture of hDPC and EC in the presence of hDP-ECM formed functional dental pulp organoids. The experimental model provides an alternative tool for toxicity screening of dental pulp capping agents and dental pulp regeneration research.

Kill-Resist-Renew Trinity: Hyperbranched Polymer with Self-Regenerating Attack and Defense for Antifouling Coatings.

Traditional antifouling coatings are generally based on a single antifouling mechanism, which can hardly meet the needs of different occasions. Here, a single "kill-resist-renew trinity" polymeric coating integrating fouling killing, resistance, and releasing functions is reported. To achieve the design, a novel monomer-tertiary carboxybetaine ester acrylate with the antifouling group N-(2,4,6-trichlorophenyl)maleimide (TCB-TCPM) is synthesized and copolymerized with methacrylic anhydride via reversible addition-fragmentation chain transfer polymerization yielding a degradable hyperbranched polymer. Such a polymer at the surface/seawater is able to hydrolyze and degrade to short segments forming a dynamic surface (releasing). The hydrolysis of TCB-TCPM generates the antifouling groups TCPM (killing) and zwitterionic groups (resistance). Such a polymeric coating exhibits a controllable degradation rate, which increases with the degrees of branching. The antibacterial assay demonstrates that the antifouling ability arise from the synergistic effect of "attacking" and "defending". This study provides a new strategy to solve the challenging problem of marine biofouling.

Surface-fragmenting hyperbranched copolymers with hydrolysis-generating zwitterions for antifouling coatings.

Zwitterionic polymers have attracted increasing attention due to their excellent fouling resistance ability and eco-friendliness. Yet, their non-degradability and hydrophilic nature limit their applications. In this study, we have prepared a novel surface-fragmenting hyperbranched copolymer with tertiary carboxybetaine ester (TCB) primary chains and poly(ε-caprolactone) (PCL) bridged chains, where the former and the latter can hydrolyze and degrade in marine environments, continuously generating zwitterions, so the polymer coating has a fouling resistant and renewable surface. Our study demonstrates that the degradation rate of the polymer is well controlled by the content of PCL bridges. Protein resistance and antibacterial assays show that the coating can inhibit the adhesion of protein and marine bacteria (Pseudomonas sp.). This new surface-fragmenting, self-regenerating hyperbranched zwitterionic copolymer has multiple applications in antifouling coatings.

Self-Generating and Self-Renewing Zwitterionic Polymer Surfaces for Marine Anti-Biofouling.

Regeneration of antifouling polymer surfaces after contamination or damage is an important issue, especially in complex marine environments. Here, inspired by the self-renewal of silyl acrylate polymers and the protein resistance of zwitterionic polymers, we prepared a novel hydrolysis-induced zwitterionic monomer, tertiary carboxybetaine triisopropylsilyl ester ethyl acrylate (TCBSA), and copolymerized it with methyl methacrylate (MMA). Such a copolymer rapidly self-generates a zwitterionic surface and provides fouling resistance in marine environments. Furthermore, TCBSA was copolymerized with MMA and 2-methylene-1,3-dioxepane (MDO), where MDO causes degradation of the polymers. Our study demonstrates that the degradation of the polymer is controlled, and the degradation rate increases with the external enzyme concentration in the seawater, leading to a self-renewing dynamic surface. Quartz crystal microbalance with dissipation measurements show that the polymeric coating with self-generating zwitterions has excellent protein resistance in seawater. Bioassays demonstrate that the coating can effectively inhibit the adhesion of marine bacteria (Pseudomonas sp.) and diatoms (Navicula incerta). The coating with a self-generating and self-renewing zwitterionic surface is potential to find applications in marine anti-biofouling.

Adjunctive Aripiprazole Treatment for Risperidone-Induced Hyperprolactinemia: An 8-Week Randomized, Open-Label, Comparative Clinical Trial.

OBJECTIVE: The present study aimed to evaluate the efficacy and safety of adjunctive aripiprazole treatment in schizophrenia patients with risperidone-induced hyperprolactinemia. METHODS: One hundred and thirteen patients who were receiving a stable dose of risperidone were randomly assigned to either adjunctive aripiprazole treatment (10 mg/day) (aripiprazole group) or no additional treatment (control group) at a 1:1 ratio for 8 weeks. Schizophrenia symptoms were measured using the Positive and Negative Syndrome Scale (PANSS). Rating scales and safety assessments (RSESE, BARS, UKU) were performed at baseline and at weeks 4 and 8. Serum levels of prolactin were determined at baseline and at weeks 2, 4, 6 and 8. Metabolic parameters were determined at baseline and again at weeks 4 and 8. RESULTS: One hundred and thirteen patients were enrolled in this study, and 107 patients completed the study (54 in the aripiprazole group, and 53 in the control group). PANSS-total scores in the aripiprazole group decreased significantly at week 4 (P = 0.003) and week 8 (P = 0.007) compared with the control group. PANSS-negative scores in the aripiprazole group also decreased significantly at week 4 (P = 0.005) and week 8 (P< 0.001) compared with the control group. Serum levels of prolactin in the aripiprazole group decreased significantly at week 2 (P< 0.001), week 4 (P< 0.001), week 6 (P< 0.001) and week 8 (P< 0.001) compared with the control group. There were no significant differences in changes of Fasting Plasma Glucose, Total cholesterol, Triglycerides and High Density Lipoprotein within each group at week 4 and 8 execpt low density lipoproteins. There was no significant difference in the incidence of adverse reactions between the two groups. CONCLUSIONS: Adjunctive aripiprazole treatment may be beneficial in reducing serum levels of prolactin and improving negative symptoms in schizophrenia patients with risperidone-induced hyperprolactinemia. TRIAL REGISTRATION: chictr.org ChiCTR-IOR-15006278.

[Understanding the elder abuse by family members].

The issue of elder abuse not only influence on the elders' physical and mental health seriously, but also increase the social burden of geriatrics disease and the corresponding social welfare agencies. The text reviews the general concept, type and characteristics, total incidence rate and all kinds of abuse, and risk factors of social psychology and psychopathology, thus the elder abuse can be identificated and intervented.