BACKGROUND AND OBJECTIVE

The human nasal passages host major human pathogens. Recent research suggests that the microbial communities inhabiting the epithelial surfaces of the nasal passages play a key factor in maintaining a healthy microenvironment by affecting both resistance to pathogens and immunological responses. Colonization of the nasal cavity by different pathogens such as Staphylococcus aureus and Klebsiella aerogenes, is associated with a higher postoperative infection morbidity. Povidone-iodine (PVP-I) as an antiseptic has been proven to display high antibacterial, antiviral, and antifungal properties even at low concentrations, and was shown to be effective in the control of infections to limit their impact and spread. It can be used as a topical antiseptic for skin decontamination and wound management, as a nasal spray, or as a gargle. There are different methods in testing the efficacy of potential antimicrobial suspensions. This study aimed to determine the concentration of PVP-I that is most effective in nasal decolonization using microsuspension test and colorimetric minimum inhibitory concentration (MIC) determination assays, resazurin microtiter assay (REMA), and Dey-Engley (D/E) neutralizer assay. The findings of this study will contribute to knowledge regarding the intended use of PVP-I in microbial control, particularly in bacterial infections.

Several dilutions (2.0%, 1.0%, 0.5%, 0.25%, 0.1% and 0.09%) of commercially bought 10% (10 mg per 100 ml) povidone-iodine were prepared and tested against a standardized inoculum (1x105) of Staphylococcus aureus and Klebsiella aerogenes at different contacttimes (5 seconds, 10 seconds, 30 seconds, 1 minute, and 5 minutes). Microdilution suspension test was performed to determine the log reduction per variable, while REMA and D/E neutralizer assay were used to determine the MIC. A value of greater than or equal to 5 log reduction was considered effective for microdilution suspension test. Estimates of agreement statistics were used to interpret the results of the assay in which the overall percent agreement (OPA), positive percent agreement (PPA), negative percent agreement (NPA), and Cohen’s kappa statistics were calculated.

Povidone-iodine concentration of 0.25% exhibited ?5 log reduction against K. aerogenes at the minimum contact time of 5 seconds. On the other hand,  a slightly higher PVP-I concentration was required to achieve ?5 log reduction for S. aureus at 0.5% concentration and a minimum contact time of 1 minute. There was an observed concordance of the results of REMA and D/E neutralizer as MIC colorimetric indicators, which yielded an overall test percent agreement of 90.30% (95% CI: 84.73–94.36), and a strong level of agreement (? = 0.8, pCONCLUSION

Low povidone-iodine concentrations (i.e., 0.5% against S. aureus and 0.25% against K. aerogenes) were observed to have bactericidal activity of at least 5 log reduction as rapid as the minimum contact time of 5 seconds. Furthermore, D/E and REMA, as colorimetric indicators, had comparable performance (OPA = 90.30%; ? = 0.8, p
Human ; Bacteria ; Povidone-iodine ; Microbial Sensitivity Tests ; Anti-infective Agents, Local ; Enterobacter Aerogenes ; Staphylococcus Aureus

TCP family as plant specific transcription factor, plays an important role in different aspects of plant development. In order to screen TCP family members in tobacco, the homologous sequences of tobacco and Arabidopsis TCP family were identified by genome-wide homologous alignment. The physicochemical properties, phylogenetic relationships and cis-acting elements were analyzed by bioinformatics. The homologous genes of AtTCP3/AtTCP4 were screened, and RT-qPCR was used to detect the changes of gene expression upon 20% PEG6000 treatment. The results show that tobacco contains 63 TCP family members. Their amino acid sequence length ranged from 89 aa to 596 aa, and their protein hydropathicity grand average of hydropathicity (GRAVY) ranged from -1.147 to 0.125. The isoelectric point (pI) ranges from 4.42 to 9.94, the number of introns is 0 to 3, and the subcellular location is all located in the nucleus. The results of conserved domain and phylogenetic relationship analysis showed that the tobacco TCP family can be divided into PCF, CIN and CYC/TB1 subfamilies, and each subfamily has a stable sequence. The results of cis-acting elements in gene promoter region showed that TCP family genes contain low docile acting elements (LTR) and a variety of stress and metabolic regulation related elements (MYB, MYC). Analysis of gene expression patterns showed that AtTCP3/AtTCP4 homologous genes (NtTCP6, NtTCP28, NtTCP30, NtTCP33, NtTCP42, NtTCP57, NtTCP63) accounted for 20% PEG6000 treatment significantly up-regulated/down-regulated expression, and NtTCP30 and NtTCP57 genes were selected as candidate genes in response to drought. The results of this study analyzed the TCP family in the tobacco genome and provided candidate genes for the study of drought-resistance gene function and variety breeding in tobacco.
Nicotiana/genetics* ; Phylogeny ; Plant Breeding ; Amino Acid Sequence ; Arabidopsis ; Polyethylene Glycols

Humans ; Spinal Fractures/etiology* ; Fractures, Compression/etiology* ; Osteoporotic Fractures/complications* ; Vertebroplasty/adverse effects* ; Bone Diseases, Metabolic/complications* ; Punctures/adverse effects* ; Treatment Outcome ; Bone Cements ; Retrospective Studies

OBJECTIVES: The current study aimed to investigate the bonding properties of a novel low-shrinkage resin adhesive containing expanding monomer and epoxy resin monomer after thermal cycling aging treatment. METHODS: Expanding monomer of 3,9-diethyl-3,9-dimethylol-1,5,7,11-tetraoxaspiro-[5,5] undecane (DDTU) as an anti-shrinkage additive and unsaturated epoxy monomer of diallyl bisphenol A diglycidyl ether (DBDE) as a coupling agent were synthesized. A blend of DDTU and DBDE at a mass ratio of 1∶1, referred to as "UE", was added into the resin matrix at the mass fraction of 20% to prepare a novel low-shrinkage resin adhesive.Then, the methacrylate resin adhesive without UE was used as the blank control group, and a commercial resin adhesive system was selected as the commercial control group. Moreover, the resin-dentin bonding and micro-leakage testing specimens were prepared for the thermal cycling aging treatment. The bonding strength was tested, the fracture modes were calculated, the bonding fracture surface was observed by scanning electron microscope (SEM), and the dye penetration was used to evaluate the tooth-restoration marginal interface micro-leakage. All the data were analyzed statistically. RESULTS: After aging, the dentin bonding strength of the experimental group was (19.20±1.03) MPa without a significant decrease (P>0.05), that of the blank control group was (11.22±1.48) MPa with a significant decrease (P<0.05) and that of the commercial control group was (19.16±1.68) MPa without a significant decrease (P>0.05). The interface fracture was observed as the main fracture mode in each group after thermal cycling by SEM. The fractured bonding surfaces of the experimental group often occurred on the top of the hybrid layer, whereas those of the blank and commercial control groups mostly occurred on the bottom of the hybrid layer. Micro-leakage rating counts of specimens before and after thermal cycling were as follows: the experimental group was primarily 0 grade, thereby indicating that a relatively ideal marginal sealing effect could be achieved (P>0.05); meanwhile, the blank control group was primarily 1 grade, and the penetration depth of dye significantly increased after thermal cycling (P<0.05); the commercial control group was primarily 0 grade without statistical difference before and after thermal cycling (P>0.05), while a significant difference was observed between the commercial control group and experimental group after thermal cycling (P<0.05). CONCLUSIONS The novel low-shrinkage resin adhesive containing 20%UE exhibited excellent bonding properties even after thermal cycling aging treatment, thereby showing a promising prospect for dental application.
Composite Resins ; Dental Bonding ; Dental Cements ; Surface Properties ; Resin Cements ; Dentin-Bonding Agents ; Dentin ; Materials Testing ; Microscopy, Electron, Scanning

Synthetic plastics have been widely used in various fields of the national economy and are the pillar industry. However, irregular production, plastic product use, and plastic waste piling have caused long-term accumulation in the environment, contributing considerably to the global solid waste stream and environmental plastic pollution, which has become a global problem to be solved. Biodegradation has recently emerged as a viable disposal method for a circular plastic economy and has become a thriving research area. In recent years, important breakthroughs have been made in the screening, isolation, and identification of plastic-degrading microorganisms/enzyme resources and their further engineering, which provide new ideas and solutions for treating microplastics in the environment and the closed-loop bio-recycling of waste plastics. On the other hand, the use of microorganisms (pure cultures or consortia) to further transform different plastic degradants into biodegradable plastics and other compounds with high added value is of great significance, promoting the development of a plastic recycling economy and reducing the carbon emission of plastics in their life cycle. We edited a Special Issue on the topic of "Biotechnology of Plastic Waste Degradation and Valorization", focusing on the researches progress in three aspects: Mining microbial and enzyme resources for plastic biodegradation, Design and engineering of plastic depolymerase, and biological high-value transformation of plastic degradants. In total, 16 papers have been collected in this issue including reviews, comments, and research articles, which provide reference and guidance for further development of plastic waste degradation and valorization biotechnology.
Biodegradable Plastics ; Biodegradation, Environmental ; Biotechnology

At present, the negative impact caused by white pollution has spread to all aspects of human society economy, ecosystem, and health, which causes severe challenges for developing the circular bioeconomy. As the largest plastic production and consumption country in the world, China has shouldered an important responsibility in plastic pollution control. In this context, this paper analyzed the relevant strategies of plastic degradation and recycling in the United States, Europe, Japan and China, measured the literature and patents in this field, analyzed the status quo of technology from the perspective of research and development trends, major countries, major institutions, and discussed the opportunities and challenges faced by the development of plastic degradation and recycling in China. Finally, we put forward future development suggestions which include the integration of policy system, technology path, industry development and public cognition.
Humans ; Plastics ; Ecosystem ; Environmental Pollution ; Recycling ; Policy

The large scale production and indiscriminate use of plastics led to serious environmental pollution. To reduce the negative effects of plastics waste on the environment, an approach of enzymatic degradation was put forward to catalyze plastics degradation. Protein engineering strategies have been applied to improve the plastics degrading enzyme properties such as activity and thermal stability. In addition, polymer binding modules were found to accelerate the enzymatic degradation of plastics. In this article, we introduced a recent work published in Chem Catalysis, which studied the role of binding modules in enzymatic hydrolysis of poly(ethylene terephthalate) (PET) at high-solids loadings. Graham et al. found that binding modules accelerated PET enzymatic degradation at low PET loading (< 10 wt%) and the enhanced degradation cannot be observed at high PET loading (10 wt%-20 wt%). This work is beneficial for the industrial application of polymer binding modules in plastics degradation.
Polyethylene Terephthalates/metabolism* ; Polymers ; Plastics ; Ethylenes

The pollution caused by improper handling of plastics has become a global challenge. In addition to recycling plastics and using biodegradable plastics, an alternative solution is to seek efficient methods for degrading plastics. Among them, the methods of using biodegradable enzymes or microorganisms to treat plastics have attracted increasing attention because of its advantages of mild conditions and no secondary environmental pollution. Developing highly efficient depolymerizing microorganisms/enzymes is the core for plastics biodegradation. However, the current analysis and detection methods cannot meet the requirements for screening efficient plastics biodegraders. It is thus of great significance to develop rapid and accurate analysis methods for screening biodegraders and evaluating biodegradation efficiency. This review summarizes the recent application of various commonly used analytical techniques in plastics biodegradation, including high performance liquid chromatography, infrared spectroscopy, gel permeation chromatography, and determination of zone of clearance, with fluorescence analysis techniques highlighted. This review may facilitate standardizing the characterization and analysis of plastics biodegradation process and developing more efficient methods for screening plastics biodegraders.
Biodegradable Plastics/chemistry* ; Biodegradation, Environmental

With the escalation of plastic bans and restrictions, bio-based plastics, represented by polylactic acid (PLA), have become a major alternative to traditional plastics in the current market and are unanimously regarded as having potential for development. However, there are still several misconceptions about bio-based plastics, whose complete degradation requires specific composting conditions. Bio-based plastics might be slow to degrade when it is released into the natural environment. They might also be harmful to humans, biodiversity and ecosystem function as traditional petroleum-based plastics do. In recent years, with the increasing production capacity and market size of PLA plastics in China, there is an urgent need to investigate and further strengthen the management of the life cycle of PLA and other bio-based plastics. In particular, the in-situ biodegradability and recycling of hard-to-recycle bio-based plastics in the ecological environment should be focused. This review introduces the characteristics, synthesis and commercialization of PLA plastics, summarizes the current research progress of microbial and enzymatic degradation of PLA plastics, and discusses their biodegradation mechanisms. Moreover, two bio-disposal methods against PLA plastic waste, including microbial in-situ treatment and enzymatic closed-loop recycling, are proposed. At last, the prospects and trends for the development of PLA plastics are presented.
Humans ; Ecosystem ; Biodegradable Plastics ; Polyesters ; Biodegradation, Environmental

Polyolefin plastics are a group of polymers with C-C backbone that have been widely used in various areas of daily life. Due to their stable chemical properties and poor biodegradability, polyolefin plastic waste continues to accumulate worldwide, causing serious environmental pollution and ecological crises. In recent years, biological degradation of polyolefin plastics has attracted considerable attention. The abundant microbial resources in the nature offer the possibility of biodegradation of polyolefin plastic waste, and microorganisms capable of degrading polyolefin have been reported. This review summarizes the research progress on the biodegradation microbial resources and the biodegradation mechanisms of polyolefin plastics, presents the current challenges in the biodegradation of polyolefin plastics, and provides an outlook on future research directions.
Plastics/metabolism* ; Polymers/metabolism* ; Polyenes ; Biodegradation, Environmental