Reusable flexible poly(vinyl alcohol)/chitosan-based polymer carbon dots composite film for acid blue 93 dye adsorption.

The design and synthesis of water-insoluble chitosan-based polymer carbon dots [P(CS-g-CA)CDs] are described. A polyvinyl alcohol/chitosan-based polymer carbon dot [PVA/P(CS-g-CA)CDs] composite film was prepared using a simple casting method to be used in dye adsorption. The composite film was characterized using FT-IR, XPS, transparency, contact angle, and mechanical properties tests, which showed the successful incorporation of P(CS-g-CA)CDs into the film and also revealed that hydrogen bonding improved the mechanical properties of the PVA film. Furthermore, the composite film displayed substantially enhanced hydrophobicity, making it suitable for use in aqueous environments. In addition, the composite film exhibited stable adsorption of acid blue 93 (AB93) at pH 2-9, with an enhanced adsorption capacity of 433.24 mg/g. The adsorption obeyed Langmuir law with an efficiency of more than 89% even after five cycles. Therefore, the PVA/P(CS-g-CA)CDs film is a promising material for the treatment of organic dye-polluted wastewater.

Carbon dots crosslinked chitosan/cellulose sponge capture of methyl blue by an adsorption process.

For environmental protection, organic dyes and solvents of industrial wastewater must be eliminated. Here, a citric acid-based carbon dots (CA-CDs) crosslinked chitosan/microcrystalline cellulose (CS/MCC/CA-CDs) sponge was synthesized to study its adsorption performance for methyl blue (MB) dye. The morphology of the sponge was a tangled fibre with a bundle formed by hydrogen bonds between CA-CDs and the CS/MCC composite matrix. The abundant amount of tangled fibre bundle units can offer plentiful active adsorption sites to collect the dye molecules. The adsorption capacity of the CS/MCC/CA-CDs sponge toward MB was 306.8 mg/g at pH 10 and a temperature of 298 K. In addition, the pseudo-second-order kinetic model was matched with the adsorption kinetic experimental data, and the adsorption isotherm data can be described by the Langmuir models. This study proposed that the CS/MCC/CA-CDs sponge adsorbent creates tremendous potential application value in wastewater treatment due to its fast kinetics, high adsorption capacity, simple preparation, and eco-friendly properties.

Polymer composite fluorescent hydrogel film based on nitrogen-doped carbon dots and their application in the detection of Hg2+ ions.

A simple microwave-assisted solvothermal method was used to prepare fluorescent nitrogen-doped carbon dots (N-CDs) with high fluorescence quantum yield (79.63%) using citric acid and N-(2-hydroxyethyl)ethylenediamine as starting materials. The PVAm-g-N-CDs grafted products were synthesized by amide bond formation between the carboxylic groups of N-CDs and amine groups of polyvinylamine (PVAm). Fluorescent hydrogel films (PVAm-g-N-CDs/PAM) were synthesized by interpenetration polymer network polymerization of PVAm-g-N-CDs and acrylamide (AM). When used for ion detection, we found that the fluorescence of the hydrogel films was clearly quenched by addition of Hg2+ . Repeatability tests on using the hydrogel films for Hg2+ detection showed that they could be applied at least three times. The PVAm-g-N-CDs/PAM could serve as an effective fluorescent sensing platform for sensitive detection of Hg2+ ions with a detection limit of 0.089 µmol/L. This work may offer a new approach for developing recoverable and sensitive N-CDs-based sensors for biological and environmental applications.

Relationship between implantation of missing anterior teeth and oral health-related quality of life.

PURPOSE: The aim of the present study was to investigate the relationship between anterior teeth implantation and oral health-related quality of life (OHRQoL). METHODS: Participants completed the Chinese version of the Oral Health Impact Profile-14 (OHIP-14) prior to implantation and at 6 months following crown restoration. Participant demographic information was recorded. Six months following implant crown restoration, participants were asked to self-assess their overall oral health and implant restoration. A Kruskal-Wallis test and Spearman correlation test were used for statistical analyses. A p value <0.05 was considered statistically significant. RESULTS: A total of 238 patients (133 women and 105 men) completed the study. OHP-14 scores were negatively correlated with self-assessment of both overall oral health (r = -0.788, p < 0.001) and implant restoration (r = -0.739, p < 0.001) after implant crown restoration. There were no significant differences between qualitative reasons for dissatisfaction or between quantity of reasons given for dissatisfaction (p = 0.845). Six months following crown restoration, the overall OHIP-14 scores and the four common factors (disability, psychological discomfort, functional limitation, pain, and discomfort) decreased significantly compared to preimplantation scores (p < 0.001). From the paired differences between genders before and after implantation, significant differences were observed in overall quality (p = 0.044) and disability (p = 0.029). Patients with a higher education level scored significantly higher on overall quality of life (p = 0.031) and psychological discomfort (p = 0.002) following crown restoration. CONCLUSIONS: Our findings indicate that the implantation of anterior missing teeth could significantly improve patient OHRQoL. Gender and education level were shown to affect implantation results.

Short communication: possible mechanism for inhibiting the formation of polymers originated from 5-hydroxymethyl-2-furaldehyde by sulfite groups in the dairy thermal process.

5-Hydroxymethyl-2-furaldehyde can undergo polymerization to form high-molecular weight molecules via the Maillard reaction during dairy thermal treatment. In this study, the effect of sulfite group on polymer formation, especially in inhibiting the formation of high-molecular weight polymers has been described. Results showed that the sulfite group significantly inhibited the increase of polymer molecular weight via prevention of the polymerization of 5-hydroxymethyl-2-furaldehyde. The formation of an intermolecular dimer based on the glucose molecule through Schiff base cyclization can lead to a competitive reaction with 1,2-enolization to reduce 5-hydroxymethyl-2-furaldehyde formation, which might be another factor in reducing the formation of high-molecular weight polymers.

Effect of localized electrochemical pH and temperature synergistic modification on the structural and antibacterial properties of pectin/polyvinyl alcohol/zinc oxide nanorod films.

Two low-methoxy pectins (LMPs) were obtained by local electrochemical pH modification using an H-type double-layer water bath sealed electrochemical cell at the voltage of 180 V for 3 h. The weight-average molecular weight (Mw) of citrus peel pectin (CPP) prepared in the anodic part at room temperature (CPP-A5/RT) and in the cathodic part at 5 °C (CPP-C5/RT) were 346 kDa and 328 kDa, respectively, and the degrees of methylation (DM) were 36.8 % and 11.9 %. Moreover, the second-order kinetic model was most appropriate for the degradation processes, as free radicals were generated in the anodic part and ß-elimination occurred in the cathodic part. Subsequently, CPP-A5/RT and CPP-C5/RT were utilized to fabricate food packaging film blending with polyvinyl alcohol (PVA), bcZnO (ZnO coupled with bentonite and colophony) nanorods, and Ca2+ ions by casting method. Then the prepared films were studied for their ability to maintain the freshness of strawberries. The addition of Ca2+ ions and bcZnO nanorods increased the thickness, water contact angle (WCA), and mechanical properties of the composite films, while decreased water vapor permeability (WVP). Therefore, the CPP-based films, supplemented with bcZnO nanorods and crosslinked with Ca2+ ions by "egg-box" model, can serve as an antibacterial food packaging material for food preservation.

[Interaction between latex microspheres and antibody proteins revealed by fluorescence spectroscopy].

Latex-antibody complexes were prepared by the method of covalent coupling and the properties of the complexes were studied by fluorescence spectrophotometric method for the purpose of revealing the interaction between latex microspheres and antibody proteins. Analysis of intrinsic fluorescence spectra showed that after being coupled with latex microspheres, the emission maximum of antibody protein showed an obvious blue shift, the intensity of emission maximum decreased significantly, the tertiary structure of antibody protein changed to some extent, the interaction between latex microspheres and antibody proteins had a great quenching effect on the intrinsic fluorescence spectra of antibody proteins, the quenching effect was enhanced along with the increasing pH value and latex concentration, and the quenching mechanism was static quenching. Results of exogenous fluorescence spectra showed that the fluorescence intensity of emission maximum was enhanced significantly after being coupled with latex microspheres, the hydrophobicity of antibody protein was decreasing with the increase in the pH values, however, due to the increasing latex concentration, the hydrophobicity antibody protein was increasing.

The clinicopathological features and treatments of odontogenic keratocysts.

An odontogenic keratocyst (OKC) is a benign but aggressive intraosseous tumor derived from the remains of the original tooth germ or dental lamina. It has a marked ability to recur and become cancerous. However, patients with early-stage OKC often have no symptoms and manifestations. The common clinical manifestation is swelling. Hence, it is critical to precisely diagnose the disease, to use differential diagnosis in combination with auxiliary examination methods, and to select the most appropriate treatment option to reduce the loss of bone tissue and the related damage to patients. In recent years, with the advancement in understanding the molecular basis of this disease and the development of early detection and targeted therapy, the diagnosis and the prognosis of OKC have been improved. The aim of this study was to provide an overview on the clinical features, diagnosis, and treatment of OKC. The molecular and genetic basis of this disease and the characteristics of malignant transformation of OKC were also discussed. Finally, we presented patient cases from our clinical practice to provide some advice on the diagnosis and treatment of OKC.

Primary Exploration of the Clinical Application of 3D-Printed Complete Dentures.

PURPOSE: To explore the applications of 3D scanning and 3D printing techniques in the restorative treatment of edentulous patients. MATERIALS AND METHODS: A total of 30 edentulous patients (Atwood classes 1 to 4) who visited The 960th Hospital of the People's Liberation Army, Jinan, China, from March 1, 2018 to May 1, 2020 were selected, and the patients were randomly divided into two groups: a traditional complete denture group (group A) and a 3D-printed complete denture group (group B). Each group comprised 15 patients. In group A, the traditional method was used to fabricate complete dentures. In group B, 3D scanning, computer-aided design (CAD), 3D printing, and the duplicate denture technique were used to fabricate the dentures. A single-blinded method was used. Patient satisfaction was measured with a 0-10 visual analog scale (VAS) at four time points: immediately and 1 month, 3 months, and 6 months after denture delivery. SPSS version 22.0 software was used to analyze the data. RESULTS: The ability to speak, ability to chew, and comfort in the two groups gradually improved at the first three time points. VAS scores increased to a satisfactory level after 3 months. The esthetics and stability of the two groups were scored high after the initial delivery. The VAS scores of the two groups regarding esthetics, ability to speak, ability to chew, stability, and comfort were not significantly different (P > .05) at any time point. The number of visits in the 3D-printed complete denture group were significantly decreased in comparison to the traditional group. CONCLUSION: The use of 3D printing for manufacturing complete dentures can rapidly restore edentulous patients and meet patient demands regarding esthetics and function.

Analyzing 2-acetyl-4(5)-(1,2,3,4-tetrahydroxybutyl)-imidazole in beverages by dispersive micro-solid phase extraction using polymer cation exchange sorbent followed by ion chromatography and liquid chromatography coupled with tandem mass spectrometry.

The presence of 2-acetyl-4(5)-(1,2,3,4-tetrahydroxybutyl)-imidazole (THI) in beverages has raised several concerns regarding its toxicity to humans. The sample preparation and detection of THI in complex matrices is challenging owing to its high water solubility. Here we reported a rapid sample preparation method based on dispersive micro-solid phase extraction (D-µ-SPE) using polymer cation exchange sorbent as sorbent for the extraction of THI from beverage samples. THI was detected by high performance anion exchange chromatography-pulsed amperometric detector (HPAEC-PAD) and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The experimental parameters of D-µ-SPE on extraction efficiency were carefully optimized. Under the optimized conditions, high recoveries (83.4-96.1%) and good reproducibility (%RSD ≤ 8.7%) were obtained using D-µ-SPE-HPAEC-PAD and D-µ-SPE-HPLC-MS/MS. Limit of quantification was 75 ng/mL for HPAEC-PAD and 5 ng/mL for HPLC-MS/MS. This work proves the potential application the newly developed method for the quantification of THI in beverages containing caramel color.

Effects of Four Different Crown Materials on the Peri-Implant Clinical Parameters and Composition of Peri-Implant Crevicular Fluid.

This study aimed to identify the preferred crown material by measuring the peri-implant clinical parameters and the concentrations of receptor activator of nuclear factor-κB ligand (RANKL), osteoprotegerin (OPG), and calcium in peri-implant crevicular fluid (PICF) with 4 different crown materials. A total of 196 patients with a single missing posterior tooth received crown restoration with cobalt-chromium (Co-Cr) porcelain-fused-to-metal (PFM; n = 50), aurum platinum (Au-Pt) PFM (n = 48), titanium (Ti) PFM (n = 52), or zirconia (Zi) all-ceramic crown (n = 46). Fifty-one natural counterpart teeth served as controls. Before and 12 months after restoration, the PICF was collected, and the concentrations of RANKL, OPG, and calcium were quantified. The peri-implant clinical parameters (plaque index, bleeding on probing, and probing depth [PD]) and gingival crevicular fluid (GCF) volumes were assessed. Twelve months after restoration, the PD and GCF volumes for the 4 experimental groups were significantly greater than those for the control group and before restoration. The Co-Cr group showed the greatest PD, GCF volume, RANKL/OPG, RANKL, and calcium ion concentration, followed by the Au-Pt group. The Ti group had the highest OPG concentration, followed by the Zi group. The RANKL and calcium ion concentrations of the Ti and Zi groups were the smallest. The Ti group had the smallest RANKL/OPG ratio, followed by the Zi group. Different crown materials differentially affected the PD, volume, RANKL/OPG ratio, OPG, RANKL, and calcium concentration. Among the 4 tested crown materials, Zi and Ti are preferred. However, some limitations of the present study should be considered.

The antibiotic activity and mechanisms of sugarcane (Saccharum officinarum L.) bagasse extract against food-borne pathogens.

Sugarcane bagasse contains natural compositions that can significantly inhibit food-borne pathogens growth. In the present study, the phenolic content in sugarcane bagasse was detected as higher than 4 mg/g dry bagasse, with 470 mg quercetin/g polyphenol. The sugarcane bagasse extract showed bacteriostatic activity against the growth of Staphylococcus aureus, Listeria monocytogenes, Escherichia coli and Salomonella typhimurium. Additionally, the sugarcane bagasse extract can increase the electric conductivity of bacterial cell suspensions causing cellular leaking of electrolytes. Results of sodium dodecyl sulfate polyacrylamide gel electrophoresis suggested the antibacterial mechanism was probably due to the damaged cellular proteins by sugarcane bagasse extract. The results of scanning electron microscopy and transmission electron microscopy showed that the sugarcane bagasse extract might change cell morphology and internal structure.

Proliferation and differentiation of osteoblasts from the mandible of osteoporotic rats.

The objective of this study was to identify the differences between osteoblasts derived from normal adult rat mandibles and osteoporotic adult rats. An osteoporotic animal model was established by performing a bilateral ovariectomy (ovx group). The proliferation and differentiation abilities of osteoblasts were determined by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-2H-tetrazolium bromide), alkaline phosphatase (ALP) and osteocalcin release (OC) assays. Transmission electron microscopy (TEM) was performed to assess differences in the ultrastructure. Proliferating cell nuclear antigen (PCNA) and uncoupling protein 2 (UCP2) protein concentrations were analyzed by Western blot. In addition, UCP2 protein in osteoblasts was assessed by immunohistochemistry staining. ATP and reactive oxygen species (ROS) concentrations were analyzed separately with ATP and ROS quantification kits. At four and 12 weeks after the operation, osteoblasts of the ovx group showed earlier attachment, fewer dead cells and faster growth compared with cells in the sham group. TEM showed that osteoblasts of the ovx group had fewer folds, lysosomes, peroxisomes and less rough endoplasmic reticulum. The results of the MTT, ALP activity and OC assays were all higher in osteoblasts from the ovx group at four or 12 weeks postsurgery than osteoblasts from the sham group. PCNA protein concentrations in the ovx group increased significantly compared with those of the sham group at four or 12 weeks after the operation, but UCP2 concentrations decreased over the same time period. UCP2 immunohistochemical staining of osteoblasts showed that the protein was concentrated in the cytoplasm and that the osteoblasts from the sham group had higher expression than those from the ovx group. The ATP and ROS concentrations of the ovx groups were significantly higher than the sham groups at four or 12 weeks postsurgery. Therefore, we concluded that there are differences in cell ultrastructure, proliferation, differentiation, ATP and ROS concentrations, and PCNA and UCP2 protein expression levels in osteoblasts from the mandibles of rats of the ovx group compared with those from the sham group.