Bio-Based Thermosetting Resins: From Molecular Engineering to Intrinsically Multifunctional Customization.

Recent years have witnessed a growing interest in bio-based thermosetting resins in terms of environmental concerns and the desire for sustainable industrial practices. Beyond sustainability, utilizing the structural diversity of renewable feedstock to craft bio-based thermosets with customized functionalities is very worthy of expectation. There exist many bio-based compounds with inherently unique chemical structures and functions, some of which are even difficult to synthesize artificially. Over the past decade, great efforts are devoted to discovering/designing functional properties of bio-based thermosets, and notable progress have been made in antibacterial, antifouling, flame retardancy, serving as carbon precursors, and stimuli responsiveness, among others, largely expanding their application potential and future prospects. In this review, recent advances in the field of functional bio-based thermosets are presented, with a particular focus on molecular structures and design strategies for discovering functional properties. Examples are highlighted wherein functionalities are facilitated by the inherent structures of bio-based feedstock. Perspectives on issues regarding further advances in this field are proposed at the end.

Retinal ischemia-reperfusion injury induces intense lipid synthesis and remodeling.

The retina is a high-metabolism tissue composed of various cell types with complex functions that relies heavily on the blood supply to maintain homeostasis. Retinal ischemia-reperfusion injury is a critical pathogenic mechanism in glaucoma, and changes in lipid molecules may lead to retinal tissue damage. However, retinal lipid profile alterations caused by this mechanism remain unclear. Thus, this study employed a retinal ischemia-reperfusion model to analyze changes in the lipid profile between sham-operated and ischemia-reperfusion groups. We discovered that ischemia-reperfusion injury-induced alterations in 338 lipid molecules, which potentially caused lipid droplet formation and mitochondrial damage. Notably, we identified characteristic changes in various lipids, including cholesterol esters, cardiolipin, and ceramide, which may serve as potential biomarkers for assessing the severity of retinal injury and therapeutic interventions. The ischemia-reperfusion-specific features identified in this study provide a more comprehensive understanding of the pathophysiological mechanisms underlying this condition.

Investigating the Impact of Sun/UV Protection and Ease of Skin Tanning on the Risk of Pseudoexfoliation Glaucoma: A Mendelian Randomization Study.

Purpose: To investigate the potential causal associations between the use of sun/ultraviolet (UV) protection and ease of skin tanning and the risk of pseudoexfoliation glaucoma (PXG) in European populations. Methods: Single nucleotide polymorphisms (SNPs) associated with the use of sun/UV protection and ease of skin tanning were selected from the UK Biobank genome-wide association study database consisting of 498,751 European participants. SNPs of PXG were obtained from the FinnGen study including 3424 PXG cases and 326,434 controls. Two-sample Mendelian randomization (MR) analyses were performed to assess the association between the use of sun/UV protection and ease of skin tanning and risk of PXG. Results: Inverse variance weighted regression of genetic susceptibility predicted that both use of sun/UV protection and ease of skin tanning were potentially positively associated with the decreased risk of PXG in the European ancestry (use of sun/UV protection: odds ratio [OR] = 0.47; 95% confidence interval [CI], 0.24-0.92; P = 0.028; ease of skin tanning: OR = 0.81; 95% CI, 0.67-0.97; P = 0.025). Conclusions: We found genetic evidence supporting a potential causal association between UV protection and a decreased risk of PXG in European population. Further research will help elucidate the underlying mechanisms and promote UV protection for eyes, especially in people with a high risk of PXG.

Preparation and Application of a Multifunctional Interfacial Modifier for Ramie Fiber/Epoxy Resin Composites.

A multi-functional modifier, which could improve the mechanical and thermal performance simultaneously, is significant in composites production. Herein, inspired by the chemistry of mussel, an interfacial modifier named FPD was designed and synthesized through one simple step, which was attached by three functional groups (including catechol, N-H bond, and DOPO). Due to the innate properties of each functional group, FPD played multiple roles: adhere to the ramie fibers from catechol and cure with the epoxy resin from -NH-, an antiflaming property from DOPO, and the compatibilizer between ramie fibers and epoxy resin was also improved by changing the polarity of ramie fiber. All of the above functions can be proved by means of water contact angle (WCA), atomic force microscope (AFM), and scanning electron microscopy (SEM), etc. After solidification, the ramie fiber/epoxy composites demonstrated superior performances in terms of good mechanical properties and excellent flame retardant property. With the addition of 30 wt.% FPD, the tensile strength and modulus of the ramie/epoxy composite showed an improvement of 37.1% and 60.9%, and flexural strength and modulus of the composite were improved by 8.9% and 19.3% comparing with no addition composite. Moreover, the composite could achieve the goal for V-0 rating in the UL-94 test and LOI value was 34.6% when the addition of FPD reached 30 wt.%. This work provided us with an efficient method for fabricating nature fiber/epoxy composites with good properties.

Does paraspinal muscle morphometry predict functional status and re-operation after lumbar spinal surgery? A systematic review and meta-analysis.

OBJECTIVES: Whether paraspinal muscle degeneration is related to poor clinical outcomes after lumbar surgery is still indistinct, which limits its clinical application. This study aimed to evaluate the predictive value of paraspinal muscle morphology on functional status and re-operation after lumbar spinal surgery. METHODS: A review of the literature was conducted using a total of 6917 articles identified from a search of PubMed, EMBASE, and Web of Science databases through September 2022. A full-text review of 140 studies was conducted based on criteria including an objective assessment of preoperative paraspinal muscle morphology including multifidus (MF), erector spinae (ES), and psoas major (PS) in addition to measuring its relationship to clinical outcomes including Oswestry disability index (ODI), pain and revision surgery. Meta-analysis was performed when required metrics could be calculated in ≥ three studies, otherwise vote counting model was a good alternative to show the effect direction of evidence. The standardized mean difference (SMD) and 95% confidence interval (CI) were calculated. RESULTS: A total of 10 studies were included in this review. Of them, five studies with required metrics were included in the meta-analysis. The meta-analysis suggested that higher preoperative fat infiltration (FI) of MF could predict higher postoperative ODI scores (SMD = 0.33, 95% CI 0.16-0.50, p = 0.0001). For postoperative pain, MF FI could also be an effective predictor for persistent low back pain after surgery (SMD = 0.17, 95% CI 0.02-0.31, p = 0.03). However, in the vote count model, limited evidence was presented for the prognostic effects of ES and PS on postoperative functional status and symptoms. In terms of revision surgery, there was conflicting evidence that FI of MF and ES could predict the incidence of revision surgery in the vote count model. CONCLUSION: The assessment of MF FI could be a viable method to stratify patients with lumbar surgery by the risk of severe functional disability and low back pain. KEY POINTS: • The fat infiltration of multifidus can predict postoperative functional status and low back pain after lumbar spinal surgery. • The preoperative evaluation of paraspinal muscle morphology is conducive for surgeons.

Synthesis of Hyperbranched Flame Retardants with Varied Branched Chains' Rigidity and Performance of Modified Epoxy Resins.

To overcome the high flammability and brittleness of epoxy resins without sacrificing their glass transition temperature (Tg) and mechanical properties, three epoxy-terminated hyperbranched flame retardants (EHBFRs) with a rigid central core and different branches, named EHBFR-HB, EHBFR-HCM, and EHBFR-HBM, were synthesized. After chemical structure characterization, the synthesized EHBFRs were introduced into the diglycidyl ether of bisphenol A (DGEBA) and cured with 4, 4-diaminodiphenylmethane (DDM). The compatibility, thermal stability, mechanical properties, and flame retardancy of the resultant resins were evaluated. Results showed that all three EHBFRs could significantly improve the fire safety of cured resins, and 30 wt. % of EHBFRs (less than 1.0 wt. % phosphorus content) endowed cured DGEBA with a UL-94 V-0 rating. In addition, the increased rigidity of branches in EHBFRs could increase the flexural strength and modulus of cured resins, and the branches with appropriate rigidity were also beneficial for improving their room temperature impact strength and Tg.

Isolation and identification of new source of bacteriocin-producing Lactobacillus plantarum C010 and growth kinetics of its batch fermentation.

The control of food-borne pathogens and spoilage organisms in meat and related products is urgently needed. Bacteriocins produced by lactic acid bacteria (LAB) are promising natural food preservatives. In this study, six bacteriocin-producing bacteria were screened from soil and fresh cow dung. Pseudomonas koreensis PS1, a specific spoilage organism from spoiled chilled pork, was used as the indicator bacteria. From the analyses, the strain C010 was selected due to its high yield, broad spectrum, and subculture stability. Through morphological, biochemical, and 16S rDNA gene sequence analysis, this strain was identified as Lactobacillus plantarum. Crude bacteriocin extracted from the cell-free supernatant (CFS) of L. plantarum C010 was stable under high temperature, ultraviolet radiation, and protease attack (pepsin, trypsin, and proteinase K). The kinetics of bacterial growth and bacteriocin production by L. plantarum C010 were analyzed during batch fermentation. Bacteriocin was produced throughout the logarithmic growth phase, and the Leudeking-Piret model characterized the synthesis of bacteriocins. The present study indicates that this novel bacteriocin produced by bacteria is a promising option for reducing spoilage microorganisms and can be widely used as a bio-preservative in meat and other foods.

Effects of exogenous AHLs on the spoilage characteristics of Pseudomonas koreensis PS1.

Some specific spoilage organisms (SSO) respond to the presence of exogenous N-acyl-homoserine lactones (AHLs) through the quorum sensing (QS) system to modulate their spoilage characteristics. To explore the effect of exogenous AHLs on the spoilage characteristics of Pseudomonas koreensis PS1 from spoiled chilled pork, four kinds of AHLs were added to the liquid medium to analyze their effect on the cell growth and spoilage characteristics of P. koreensis PS1, and N-hexanoyl-l-homoserine lactone (C6-HSL) was added to evaluate its effect on spoilage characteristics of P. koreensis PS1 inoculated in fresh chilled pork. The results showed that the addition of low concentrations of C6-HSL (10 µmol/L) to the liquid medium could remarkably promote the protease activity, lipase activity, and biofilm formation of P. koreensis PS1 (p < 0.05), and more than 30 µmol/L C6-HSL could significantly increase the cell density (p < 0.05). Furthermore, the addition of 10 µmol/L C6-HSL into fresh chilled pork could increase the lipase and protease activities of P. koreensis PS1. The enzyme activity accelerated the decomposition of total protein, total fat, and total sugar, and led to an increase in putrescine, tyramine, cadaverine, and total volatile basic nitrogen (TVB-N) content in chilled pork during the storage at 4°C. PRACTICAL APPLICATION: The infestation of chilled pork with SSO may be a challenge for the meat industry. In this study, exogenous AHLs were found to have a positive effect on the spoilage of chilled pork. The elimination of the QS phenomenon of bacteria should be considered when looking for ways to prolong the preservation of chilled pork.

A New Sight into Bio-Based Polybenzoxazine: From Tunable Thermal and Mechanical Properties to Excellent Marine Antifouling Performance.

With the rapid development of bio-based polymers, polybenzoxazine derived from renewable resources has been widely investigated. However, there are few reports on the functional application of bio-based polybenzoxazine based on the special chemical structures of renewable compounds. In this work, an easy approach to prepare the polybenzoxazines with varied thermomechanical properties and excellent marine antifouling performance from renewable resources is presented. After a variety of main-chain-type benzoxazine polymers (MCBPs) were synthesized from the renewable daidzein, furfurylamine, polyetheramine, and paraformaldehyde, their chemical structures were identified by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy (1H NMR). Then, their curing behaviors were monitored by differential scanning calorimetry and rheological tests. Results revealed that the cross-linked MCBPs with varied thermomechanical properties could be easily prepared by adjusting the molar ratio of polyetheramine and furfuramine. Notably, these cured MCBP films demonstrated excellent antibacterial and algaecidal properties due to the presence of daidzein and furan units. This work first presents the new application prospect of bio-based MCBPs, for example, in marine antifouling coatings.

Biobased Benzoxazine Derived from Daidzein and Furfurylamine: Microwave-Assisted Synthesis and Thermal Properties Investigation.

A biobased benzoxazine resin (Dz-f) demonstrating excellent thermal properties was synthesized from daidzein and furfurylamine by using a microwave heating method. The chemical structure of synthesized benzoxazine monomer was identified by FTIR and NMR (1 H and 13 C NMR) before it was cured and its thermal properties evaluated by differential scanning calorimetry (DSC), TGA, and dynamic mechanical analysis (DMA). The cured resin p(Dz-f) exhibited a glass transition temperature (Tg ) of 391 °C, a very high char yield of 68.7 %, and outstanding thermal stability; the Tg value obtained was the highest thermal stability value ever reported for polybenzoxazine with a high biobased content. Moreover, Dz-f demonstrated a satisfying processability, which was rare for the high-performance thermosetting resins. This work provided us with a new strategy for the preparation of high biocontent resins with excellent thermal properties. In addition, the combination of biobased feedstocks with a microwave-assisted heating method as well as the potential application of this approach in high-end fields might perpetuate remarkable progress towards the sustainable development of the polymeric industry.