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

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

Plastics are one of the most important polymers with huge global demand. However, the downsides of this polymer are that it is difficult to degrade, which causes huge pollution. The environmental-friendly bio-degradable plastics therefore could be an alternative and eventually fulfill the ever-growing demand from every aspect of the society. One of the building blocks of bio-degradable plastics is dicarboxylic acids, which have excellent biodegradability and numerous industrial applications. More importantly, dicarboxylic acid can be biologically synthesized. Herein, this review discusses the recent advance on the biosynthesis routes and metabolic engineering strategies of some of the typical dicarboxylic acids, in hope that it will help to provide inspiration to further efforts on the biosynthesis of dicarboxylic acids.
Biodegradable Plastics ; Dicarboxylic Acids ; Polymers/metabolism* ; Biodegradation, Environmental ; Metabolic Engineering

Znic (Zn) alloys with good cytocompatibility and suitable degradation rate have been a kind of biodegradable metal with great potential for clinical applications. This paper summarizes the biological role of degradable Zn alloy as bone implant materials, discusses the mechanical properties of different Zn alloys and their advantages and disadvantages as bone implant materials, and analyzes the influence of different processing strategies (such as alloying and additive manufacturing) on the mechanical properties of Zn alloys. This paper provides systematic design approaches for biodegradable Zn alloys as bone implant materials in terms of the material selection, product processing, structural topology optimization, and assesses their application prospects with a view to better serve the clinic.
Orthopedics ; Zinc ; Alloys ; Dental Materials ; Prostheses and Implants

OBJECTIVE: To explore the percutaneous hollow screw internal fixation combined with cementoplasty in the treatment of periacetabular metastasis. METHODS: A retrospective study was performed on 16 patients with periacetabular metastasis who were treated with percutaneous hollow screw internal fixation combined with cementoplasty between May 2020 and May 2021. There were 9 males and 7 females. The age ranged from 40 to 73 years, with an average of 53.6 years. The tumor involved around the acetabulum, and 6 cases were located on the left and 10 cases on the right. Operation time, frequency of fluoroscopy, bed rest time, and complications were recorded. Before operation, and at 1 weeks, 3 months after operation, the visual analogue scale (VAS) score was used to evaluate the pain degree, the short-form 36 health survey scale (SF-36) score was used to evaluate the quality of life. At 3 months after operation, the Musculoskeletal Tumor Society (MSTS) scoring system was used to evaluate the functional recovery of patients. During follow-up, the loosening of internal fixator and bone cement leakage were observed by X-ray film. RESULTS: All patients were performed operation successfully. The operation time ranged from 57 to 82 minutes, with an average of 70.4 minutes. The frequency of intraoperative fluoroscopy was 16-34 times, with an average of 23.1 times. After operation, 1 case of incision hematoma and 1 case of scrotal edema occurred. All patients felt the pain relieved after operation. The patients started walking at 1-3 days after operation, with an average of 1.4 days. All patients were followed up 6-12 months (mean 9.7 months). The VAS and SF-36 scores significantly improved after operation when compared with the preoperative scores, and the scores at 3 months after operation were significant better than those at 1 week after operation ( P<0.05). At 3 months after operation, the MSTS score ranged from 9 to 27, with an average of 19.8. Among them, 3 cases were excellent (18.75%), 8 cases were good (50%), 3 cases were fair (18.75%), and 2 cases were poor (12.5%). The excellent and good rate was 68.75%. And 11 patients returned to normal walking, 3 had mild claudication, and 2 had obvious claudication. Radiological examination showed that there were 2 cases of bone cement leakage after operation, and there was no internal fixator loosening or displacement. CONCLUSION Percutaneous hollow screw internal fixation combined with cementoplasty can effectively relieve pain and improve the quality of life of patients with periacetabular metastasis.
Male ; Female ; Humans ; Adult ; Middle Aged ; Aged ; Spinal Fractures/surgery* ; Retrospective Studies ; Bone Cements ; Quality of Life ; Treatment Outcome ; Fracture Fixation, Internal ; Bone Screws ; Cementoplasty ; Pain

OBJECTIVE: To analyze the correlation between bone cement cortical leakage and injury degree of osteoporotic vertebral compression fracture (OVCF) after percutaneous kyphoplasty (PKP), and to provide guidance for reducing clinical complications. METHODS: A clinical data of 125 patients with OVCF who received PKP between November 2019 and December 2021 and met the selection criteria was selected and analyzed. There were 20 males and 105 females. The median age was 72 years (range, 55-96 years). There were 108 single-segment fractures, 16 two-segment fractures, and 1 three-segment fracture. The disease duration ranged from 1 to 20 days (mean, 7.2 days). The amount of bone cement injected during operation was 2.5-8.0 mL, with an average of 6.04 mL. Based on the preoperative CT images, the standard S/H ratio of the injured vertebra was measured (S: the standard maximum rectangular area of the cross-section of the injured vertebral body, H: the standard minimum height of the sagittal position of the injured vertebral body). Based on postoperative X-ray films and CT images, the occurrence of bone cement leakage after operation and the cortical rupture at the cortical leakage site before operation were recorded. The correlation between the standard S/H ratio of the injured vertebra and the number of cortical leakage was analyzed. RESULTS: Vascular leakage occurred in 67 patients at 123 sites of injured vertebrae, and cortical leakage in 97 patients at 299 sites. Preoperative CT image analysis showed that there were 287 sites (95.99%, 287/299) of cortical leakage had cortical rupture before operation. Thirteen patients were excluded because of vertebral compression of adjacent vertebrae. The standard S/H ratio of 112 injured vertebrae was 1.12-3.17 (mean, 1.67), of which 87 cases (268 sites) had cortical leakage. The Spearman correlation analysis showed a positive correlation between the number of cortical leakage of injured vertebra and the standard S/H ratio of injured vertebra ( r=0.493, P<0.001). CONCLUSION The incidence of cortical leakage of bone cement after PKP in OVCF patients is high, and cortical rupture is the basis of cortical leakage. The more severe the vertebral injury, the greater the probability of cortical leakage.
Male ; Female ; Humans ; Aged ; Kyphoplasty/methods* ; Bone Cements ; Fractures, Compression/surgery* ; Spinal Fractures/surgery* ; Retrospective Studies ; Osteoporotic Fractures/etiology* ; Treatment Outcome ; Vertebroplasty/methods*

OBJECTIVE: To evaluate the effectiveness of limited internal fixation combined with a hinged external fixator in the treatment of peri-elbow bone infection. METHODS: The clinical data of 19 patients with peri-elbow bone infection treated with limited internal fixation combined with a hinged external fixator between May 2018 and May 2021 were retrospectively analyzed. There were 15 males and 4 females with an average age of 44.6 years (range, 28-61 years). There were 13 cases of distal humerus fractures and 6 cases of proximal ulna fractures. All the 19 cases were infected after internal fixation of fracture, and 2 cases were complicated with radial nerve injury. According to Cierny-Mader anatomical classification, 11 cases were type Ⅱ, 6 cases were type Ⅲ, and 2 cases were type Ⅳ. The duration of bone infection was 1-3 years. After primary debridement, the bone defect was (3.04±0.28) cm, and the antibiotic bone cement was implanted into the defect area, and the external fixator was installed; 3 cases were repaired with latissimus dorsi myocutaneous flap, and 2 cases were repaired with lateral brachial fascial flap. Bone defects repair and reconstruction were performed after 6-8 weeks of infection control. The wound healing was observed, and white blood cell (WBC), erythrocyte sedimentation rate (ESR), and C-reaction protein (CRP) were reexamined regularly after operation to evaluate the infection control. X-ray films of the affected limb were taken regularly after operation to observe the bone healing in the defect area. At last follow-up, the flexion and extension range of motion and the total range of motion of the elbow joint were observed and recorded, and compared with those before operation, and the function of the elbow joint was evaluated by Mayo score. RESULTS: All patients were followed up 12-34 months (mean, 26.2 months). The wounds healed in 5 cases after skin flap repair. Two cases of recurrent infection were effectively controlled by debridement again and replacement of antibiotic bone cement. The infection control rate was 89.47% (17/19) in the first stage. Two patients with radial nerve injury had poor muscle strength of the affected limb, and the muscle strength of the affected limb recovered from grade Ⅲ to about grade Ⅳ after rehabilitation exercise. During the follow-up period, there was no complication such as incision ulceration, exudation, bone nonunion, infection recurrence, or infection in the bone harvesting area. Bone healing time ranged from 16 to 37 weeks, with an average of 24.2 weeks. WBC, ESR, CRP, PCT, and elbow flexion, extension, and total range of motions significantly improved at last follow-up ( P<0.05). According to Mayo elbow scoring system, the results were excellent in 14 cases, good in 3 cases, and fair in 2 cases, and the excellent and good rate was 89.47%. CONCLUSION Limited internal fixation combined with a hinged external fixator in the treatment of the peri-elbow bone infection can effectively control infection and restore the function of the elbow joint.
Male ; Female ; Humans ; Adult ; Elbow ; Elbow Joint/surgery* ; Retrospective Studies ; Bone Cements ; Treatment Outcome ; External Fixators ; Fracture Fixation, Internal/methods* ; Fractures, Bone ; Range of Motion, Articular