Polyethylene terephthalate (PET) fibers are characterized by exceptional mechanical strength, and textiles blended with cotton fibers combine both comfort and durability, showcasing widespread use in daily applications. However, improper disposal of discarded polyester-cotton textiles has resulted in severe environmental pollution, necessitating urgent and effective mitigation strategies. Enzymatic recycling of textiles offers superior environmental benefits and holds greater potential for industrial applications than alternative recycling methods. This study aims to explore a large-scale solution for the treatment of waste textiles, particularly addressing the challenge of resource recovery from polyester-cotton blended fabrics. An innovative enzymatic depolymerization process has been developed to achieve the recovery of high-purity terephthalic acid monomers. Experiments were conducted on three different textile blends with polyester-to-cotton ratios of 65/35, 70/30, and 80/20, and the influences of different colors on the process were investigated. Initially, the textiles were pretreated through mechanical grinding, which was followed by depolymerization of cotton fibers with commercial cellulase. The crystallinity of PET in the textiles was reduced through a rapid heating and cooling process. Subsequently, the PET was depolymerized by the engineered PET hydrolase. The results demonstrated that after decolorization and separation of terephthalic acid (TPA) from the reaction system, the monomer recovery rates for the three textile blends (65/35, 70/30, and 80/20) reached 90%, 91%, and 92%, respectively. Characterization analysis by nuclear magnetic resonance (NMR) confirmed that the purity of the recovered TPA was greater than 99%. In conclusion, the fully enzymatic recycling process developed in this study shows considerable promise for large-scale industrial applications and is anticipated to significantly advance the adoption and development of enzymatic recycling technologies for PET in industrial processes.
Phthalic Acids/chemistry* ; Polyesters/chemistry* ; Textiles ; Cotton Fiber ; Polyethylene Terephthalates/chemistry* ; Cellulase/chemistry* ; Recycling/methods* ; Polymerization

This study aims to optimize the process for preparing chitosan-based ultrasound-coupled hydrogel pads and investigate their application potential in ultrasonography. Chitosan, 2-acrylamido-2-methylpropanesulfonic acid, and N-isopropylacrylamide were used as the main materials to prepare chitosan-based ultrasound-coupled hydrogel pads. The free-radical polymerization conditions were optimized by a three-factor, three-level orthogonal test with the tensile strength and ultrasound image quality of the hydrogel pads as evaluation indicators. The optimal prescription was selected by optimizing three factors of raw material ratio, polymerization temperature, and freeze-drying time. The structure and performance of the hydrogel pads were characterized by a scanning electron microscope, a universal testing machine, and an ultrasonic diagnostic instrument. The results showed that the optimal prescription was as follows: the chitosan: 2-acrylamide-2-methylpropanesulfonic acid: N-isopropylacrylamide ratio of 2:0.55:17.27, the polymerization temperature of 25 ℃, and the freeze-drying time of 48 h. The ultrasonically-coupled hydrogel pads prepared under these conditions were transparent, with a porous structure, good adhesion, and high tensile strength. The hydrogel pads had good swelling properties and the swelling degree decreased slowly on day 10. The quality of the ultrasound images obtained via chitosan-based hydrogel pads was not significantly different from that obtained via medical ultrasound coupling agent. In this study, we analyzed the effects of different preparation processes on the gel formation of chitosan-based ultrasound-coupled hydrogel pads. The hydrogel pads were transparent and mild and non-irritating to the human body, serving as an ultrasound transmission material for ultrasonography.
Chitosan/chemistry* ; Hydrogels/chemistry* ; Acrylamides/chemistry* ; Ultrasonography ; Polymerization ; Sulfonic Acids/chemistry* ; Alkanesulfonates/chemistry* ; Tensile Strength ; Freeze Drying ; Temperature

Bulk-fill composite resin are simple to operate, and they reduce polymerization shrinkage and microleakage compare to traditional resin-based composites. However, their clinical application could be affected by numerous factors, such as the material itself, light curing, placement techniques, storage condition, and preheating. This review aimed to summarize the definitions, classifications, indications, clinical properties, and influencing factors of the clinical application of bulk-fill resin-based composites and discuss the ways to improve their clinical effectiveness.
Composite Resins ; Dental Materials ; Materials Testing ; Polymerization ; Surface Properties

The restorative procedure in posterior teeth involves clinical steps related to professional skill, especially when using the incremental technique, which may fail in the long term. A recent alternative is bulk-fill resins, which can reduce polymerization shrinkage, decreasing clinical problems such as marginal leakage, secondary caries, and fracture. This scientific study aims to report a clinical case using bulk-fill resin with an occlusal matrix. As determined in the treatment plan, an acrylic resin matrix was produced to establish an improved oral and aesthetic rehabilitation of the right mandibular first molar, which presented a carious lesion with dentin involvement. The occlusal matrix is a simple technique that maintains the original dental anatomy, showing satisfactory results regarding function and aesthetic rehabilitation.
Composite Resins ; Dental Caries ; Dentin ; Esthetics ; Molar ; Polymerization ; Polymers ; Rehabilitation ; Tooth

In patients with fully edentulous jaw, treatment of complete dentures should be carried out in many stages when following the conventional methods. Therefore there were disadvantages such as multiple visits to dental clinic is inevitable. In addition, errors caused by polymerization shrinkage, which happens during the fabrication of denture, and difficulties in reproduction of damaged or lost denture were considered as disadvantages. But nowadays, computer-aided design and computer-aided manufacturing (CAD/CAM) system is widely used in dentistry and it has begun to expand its spectrum in manufacturing complete dentures. Using CAD/CAM system to fabricate complete dentures can reduce the number of patient's visit and clinical chair time, since taking impression, recording jaw relation, and selection of artificial teeth are performed at the same time during the first visit, and delivering of dentures during the second visit is possible. In addition, because 3D-Printing technology is used, errors by polymerization shrinkage can be reduced. Among the companies that fabricate complete dentures using CAD/CAM system, DENTCA CAD/CAM denture (DENTCA Inc., Los Angeles, CA, USA) is the most commercialized company. In this case, we treated patients of complete dentures using conventional complete denture method and DENTCA CAD/CAM denture system in the same patient. We would like to report this case because we have achieved good results not only in functional aspects of pronunciation, chewing, and swallowing but also in aesthetic aspects.
Computer-Aided Design ; Deglutition ; Dental Clinics ; Dentistry ; Denture, Complete ; Dentures ; Humans ; Jaw ; Jaw, Edentulous ; Mastication ; Methods ; Polymerization ; Polymers ; Reproduction ; Tooth, Artificial

This study aimed to determine whether the curing times of Xtra Power and High Power modes of high-power light emitting diode (LED) curing light are sufficient for polymerization of resin sealants. The specimens were prepared and their microhardness values were measured and compared with those of specimens polymerized under conventional LED curing light.The filled sealant polymerized for 8 seconds in the High Power mode and for 3 seconds in the Xtra Power mode showed significantly lower microhardness than the control specimen (p = 0.000). The unfilled sealant polymerized for 8, 12 seconds in the High Power mode and for 6 seconds in the Xtra Power mode showed significantly lower microhardness than the control specimen (p = 0.000).The results of this study suggest that the short curing time with the Xtra Power and High Power modes of highpower LED curing light are not sufficient for adequate polymerization of sealants under specific conditions, taking into account the curing times and the type of sealant.
Polymerization ; Polymers

The aim of this study was to compare the degree of conversion and polymerization shrinkage of low and high viscosity bulk-fill giomer-based and resin-based composites. Two bulk-fill giomer (Beautifil Bulk Restorative (BBR), Beautifil Bulk Flowable (BBF)), two bulk-fill (Tetric N-Ceram Bulk-fill (TBF), SureFil SDR flow (SDR)) and two conventional resin composites (Tetric N-Ceram (TN), Tetric N-flow (TF)) were selected for this study. The degree of conversion was measured by using Fourier transform infrared spectroscopy. Polymerization shrinkage was measured with the linometer. For all depth, BBR had the lowest degree of conversion and SDR had the highest. At 4 mm, the degree of conversion of low and high viscosity bulk-fill giomer resin composites was lower than that of bulk-fill resin composites (p < 0.05). At the depth between 2 mm and 4 mm, there were significant difference with TBF, TN and TF (p < 0.05), while no significant difference in the degree of conversion was measured for BBR, BBF and SDR. Polymerization shrinkage of six resin composites decreased in the following order: TF > SDR > BBF > TBF > TN and BBR (p < 0.05). Polymerization shrinkage of bulk-fill giomer resin composites was lower than that of bulk-fill resin composites (p < 0.05). From this study, it is found that the bulk-fill giomer resin composites and TBF were not sufficiently cured in 4 mm depth. The degree of conversion of low and high viscosity bulk-fill giomer resin composites was significantly lower than bulk-fill resin composites in both 2 mm and 4 mm depths. Therefore, such features of bulk-fill giomer resin composites should be carefully considered in clinical application.
Polymerization ; Polymers ; Spectroscopy, Fourier Transform Infrared ; Viscosity

The purpose of this study was to evaluate polymerization of TheraCal LC, one of the tricalcium silicate cements. To measure the Vickers hardness number (VHN), the specimens were cured at different light curing time and distance.As a result, the VHN of the upper surface was significantly higher than the lower surface's in all groups (p < 0.05). The VHN of the lower surface was increased significantly with the increase of the light curing time in all distance (p < 0.05). When the distance was more than 4.0 mm at all light curing time, the VHN of lower surface was significantly decreased (p < 0.05). When the specimen was light cured for 20 seconds, the VHN of the lower surface did not exceed 2, which corresponds to 10% of the upper surface's.These results suggested that the 20 second light curing time was not sufficient to polymerize the lower surface under specific conditions and that light-curing time should be increased.
Hardness ; Polymerization ; Polymers ; Silicates

PURPOSE: This study evaluated the efficacy of blood mixed cement for osteoporotic vertebral compression fractures in reducing the complications of percutaneous vertebroplasty using conventional cement. MATERIALS AND METHODS: This study was performed retrospectively in 80 patients, from January 2016 to January 2017. Porous cement was formed by mixing 2, 4, and 6 ml of blood with 20 g of cement used previously. A tube with a diameter and length of 2.8 mm and 215 mm, respectively, was used and the polymerization temperature, setting time, and optimal passing-time were measured and compared with those using only conventional cement. Radiologically, the results were evaluated and compared. RESULTS: The polymerization temperature was 70.3℃, 55.3℃, 52.7℃, and 45.5℃ in the conventional cement (R), 2 ml (B2), 4 ml (B4), and 6 ml (B6), respectively, and the corresponding setting time decreased from 960 seconds (R) to 558 seconds (B2), 533 seconds (B4), and 500 seconds (B6). The optimal passing-time was 45 seconds (B2), 60 seconds (B4), and 78 seconds (B6) at 73 seconds (R), respectively and as the amount of blood increased, it was similar to the cement passing-time. The radiological results showed that the height restoration rates and the vertebral subsidence rates similar among the groups. Two cases of adjacent vertebral compression fractures in the R group and one in the B2 and B4 groups were encountered, and the leakage rate of the cement was approximately two times higher than that in the conventional cement group. CONCLUSION: In conventional percutaneous vertebroplasty, the procedure of using autologous blood with cement decreased the polymerization temperature, reduced the setting time, and the incidence of cement leakage was low. These properties may contribute to more favorable mechanical properties that can reduce the complications compared to conventional cements alone.
Fractures, Compression ; Humans ; Incidence ; Polymerization ; Polymers ; Retrospective Studies ; Vertebroplasty

A new method to express oligomerized feruloyl esterase (FAE) in Pichia pastoris GS115 to improve the catalytic efficiency was developed. It was realized by fusing the foldon domain at the C-terminus of FAE, and the fusion protein was purified by histidine tag. Fusion of the feruloyl esterase with the foldon domain resulted spontaneously forming a trimer FAE to improve the catalytic performance. The oligomerized FAE and monomeric FAE were obtained by purification. The apparent molecular weight of the oligomerized FAE was about 110 kDa, while the monomeric FAE about 40 kDa, and the optimum temperature of the oligomerized FAE was 50 °C, which is the same as the monomeric one. The optimal pH of the oligomerized FAE is 5.0, while the optimal pH of the monomer FAE is 6.0. When compared with the monomeric ones, the catalytic efficiency (kcat/Km) of the oligomerized FAE increased 7.57-folds. The catalytic constant (kcat) of the oligomerized FAE increased 3.42-folds. The oligomerized FAE induced by foldon have advantages in the catalytic performances, which represents a simple and effective enzyme-engineering tool. The method proposed here for improving the catalytic efficiency of FAE would have great potentials for improving the catalytic efficiency of other enzymes.
Carboxylic Ester Hydrolases ; metabolism ; Catalysis ; Molecular Weight ; Pichia ; genetics ; metabolism ; Polymerization ; Protein Engineering ; Substrate Specificity