Effects of chronic fluorosis on the brain.

This article reviews the effects of chronic fluorosis on the brain and possible mechanisms. We used PubMed, Medline and Cochraine databases to collect data on fluorosis, brain injury, and pathogenesis. A large number of in vivo and in vitro studies and epidemiological investigations have found that chronic fluorosis can cause brain damage, resulting in abnormal brain structure and brain function.Chronic fluorosis not only causes a decline in concentration, learning, and memory, but also has mental symptoms such as anxiety, tension, and depression. Several possible mechanisms that have been proposed: the oxidative stress and inflammation theory, neural cell apoptosis theory, neurotransmitter imbalance theory, as well as the doctrine of the interaction of fluorine with other elements. However, the specific mechanism of chronic fluorosis on brain damage is still unclear. Thus, a better understanding of the mechanisms via which chronic fluorosis causes brain damage is of great significance to protect the physical and mental health of people in developing countries, especially those living in the endemic areas of fluorosis. In brief, further investigation concerning the influence of fluoride on the brain should be conducted as the neural damage induced by it may bring about a huge problem in public health, especially considering growing environmental pollution.

The cognitive impairment and risk factors of the older people living in high fluorosis areas: DKK1 need attention.

OBJECTIVE: To evaluate cognitive impairment and risk factors of elders in high fluoride drinking water areas and investigate whether DKK1 is involved in this disorder. METHODS: MoCA-B and AD-8 were used to measure the cognitive functions of 272 and 172 subjects over the age of 60 came from the high and normal fluoride drinking water areas respectively, general information and peripheral blood were collected, the level of SOD, GSH and MDA were measured, mRNA level of DKK1, the concentration of blood fluoride and the polymorphism of APOE were tested. RESULTS: The blood fluoride concentration, mRNA level of DKK1 and ratio of abnormal cognitive function of subjects in high fluorine drinking water areas were higher than those in normal areas. The level of SOD of subjects in high fluorine drinking water was low compared with those in normal areas. The level of MDA and GSH had no difference between the two crowds in different fluorine drinking water areas. There were differences in cigarette smoking, education, dental status, hypertension, hyperlipidaemia and APOE results between the two crowds in different fluorine drinking water areas. The mRNA level of DKK1 and the level of cognitive function showed a positive correlation and DKK1 was one of five risk factors involved in cognitive impairment of older people living in high fluorosis areas. CONCLUSIONS: The cognitive functions could be impaired in the older people living in high fluoride drinking water areas, and DKK1 may as a potential intervention point of this brain damage process need attention.

EGb-761 Attenuates the Anti-proliferative Activity of Fluoride via DDK1 in PC-12 Cells.

EGb-761 is commonly used as a treatment for ischemic brain injury, neurodegenerative diseases and some types of tumors (Christen and Maixent, in Cell Mol Biol 48(6):601-611, 2002). However, it is unclear whether EGb-761 affects the proliferation of cells exposed to fluoride. In this study, the proliferation and apoptosis of PC-12 cells exposed to fluoride were investigated and EGb-761 was used to protect PC-12 cells against the effects of fluoride. We found that the canonical Wnt signaling pathway was involved in the anti-proliferation of PC-12 cells exposed to fluoride. Furthermore, the results also showed that EGb-761 could attenuate the anti-proliferative activity of fluoride via DDK1 in PC-12 cells. This study may provide a new method for protecting against the inhibition of cell proliferation induced by fluoride.

Treatment of the terephthalic acid-containing wastewater using a biological-aerated filter.

In this paper, the biological-aerated filter (BAF) was employed to treat the wastewater containing terephthalic acid (TA). Factors that affected the efficiency of TA and CODCr removal were evaluated experimetally, including pH, hydraulic loading, hydraulic retention time (HRT) and TA volume loading. At pH 7-8, hydraulic loading rate 0.067-0.48 m3/(m2 h), HRT more than 3.5h and TA loading 0.04-0.15g/(m3 d), the TA and CODCr removal efficiency was more than 93% and 87%, respectively. The mathematical model of matrix (TA) was obtained by Monod's relation and the experimental parameters of the model were 1.972 g/(m2d) and 9.782 mg/L.

Treatment of severe open bite and mandibular condyle anterior displacement by mini-screws and four second molars extraction: A case report.

BACKGROUND: Temporomandibular joint (TMJ) disorders are closely related to high-angle and skeletal Class II malocclusion. Sometimes pathological changes in the mandibular condyle can cause open bite to occur after growth is complete. CASE SUMMARY: This article is about the treatment of an adult male patient with a severe hyperdivergent skeletal Class II base, an unusual and gradually occurring open bite and an abnormal mandibular condyle anterior displacement. Because the patient refused surgery, four second molars with cavities and root canal therapy were extracted, and four mini-screws were used for intrusion of the posterior teeth. The treatment duration was 22 mo, and after the treatment, the open bite was corrected and the displaced mandibular condyles were seated back to the articular fossa as shown by cone-beam computed tomography (CBCT). Based on the patient's open bite history, the result of clinical examinations and CBCT comparisons, we believe it is possible that the occlusion interference was eliminated after the four second molars were extracted and the posterior teeth were intruded, and the patient's condyle spontaneously returned to its physiologic position. Finally, a normal overbite was established, and stable occlusion was achieved. CONCLUSION: This case report suggested that identifying the cause of open bite is essential, and the TMJ factors for hyperdivergent skeletal Class II cases should be particularly examined. For these cases, intruding posterior teeth may place the condyle in a more appropriate position and provide an environment suitable for TMJ recovery.

Investigation of excipients impact on polysorbate 80 degradation in biopharmaceutical formulation buffers.

A study on the polysorbate 80 stability in various formulation buffers commonly used in biopharmaceuticals was performed, to investigate the excipients influence on polysorbate 80 degradation. Polysorbate 80 is a common excipient in biopharmaceutical products. However, its degradation will potentially impact the drug product quality, and may trigger protein aggregation and particles formation. Due to the heterogeneity of the polysorbates and the mutual effects with other formulation compositions, the study of polysorbate degradation is challenging. Herein, a real-time stability study was designed and performed. The polysorbate 80 degradation trend was monitored by fluorescence micelle-based assay (FMA), reversed-phase-ultra-performance liquid chromatography-evaporative light scattering detector (RP-UPLC-ELSD) assay, and LC-MS assay. These assays provide orthogonal results to reveal both the micelle-forming capability and the compositional changes of polysorbate 80 in different buffer systems. The degradation occurred after a period of storage under 25 °C in different trend, which indicates the excipients could impact the degradation kinetics. Upon comparison, the degradation is prone to happen in histidine buffer than in acetate, phosphate or citrate buffers. LC-MS confirms oxidation as an independent degradation pathway with detection of the oxidative aldehyde. Thus, it is necessary to pay more attention to the excipients selection and their potential impact on polysorbate 80 stability to achieve longer shelf life for the biopharmaceuticals. Besides, the protective roles of several additives were figured out, which could be applied as potential industrial solutions to the polysorbate 80 degradation issues.

Cell membrane derived liposomes loaded with DNase I target neutrophil extracellular traps which inhibits colorectal cancer liver metastases.

Neutrophil extracellular traps (NETs) are web-like chromatin structures that are coated with granule proteins and trap microorganisms. However, NETs can damage the host tissue, contribute to the development of autoimmunity and lead to other dysfunctional outcomes in noninfectious diseases, including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), diabetes, atherosclerosis, vasculitis, thrombosis, and cancer. As a potential therapeutic approach, targeted ablation of neutrophil extracellular traps is of utmost importance for the treatment of NET-associated diseases. Here, the specific interaction between CCDC25 and NETs was exploited to produce biomimetic CCDC25-overexpressing cell membrane hybrid liposomes capable of targeting NETs in NET-associated diseases. The hybrid liposomes were constructed by fusing cell membrane nanovesicles derived from genetically engineered cells, which stably express CCDC25, and the resulting cell membrane hybrid liposomes exhibited enhanced affinity for NETs in two different NET-associated disease models. Furthermore, after encapsulation of DNase I in the liposomes, the nanoformulation efficiently eliminated NETs and significantly suppressed the recruitment of neutrophils. Overall, we present a bionic nanocarrier that specifically targets NETs in vivo and successfully inhibits colorectal cancer liver metastases; importantly, this could be a promising therapeutic approach for the treatment of NET-associated diseases.

Orthodontic-surgical treatment of an Angle Class II malocclusion patient with mandibular hypoplasia and missing maxillary first molars: A case report.

BACKGROUND: Adult patients presenting with Angle Class II division 1 malocclusions that have a strong skeletal etiology can be challenging for clinicians, particularly if accompanied by retrognathia of the mandible and a dolichofacial growth pattern. CASE SUMMARY: In this case report, we describe the successful orthodontic and surgical management of a 20-year-old woman with an Angle Class II malocclusion with a severe anteroposterior skeletal discrepancy characterized by mandibular deficiency. She had incompetent lips, dental and skeletal Class II malocclusion, high mandibular plane angle, mild mandibular crowding, and two missing maxillary first molars. The treatment plan comprised: (1) Extraction of two mandibular second premolars to decompensate and retract mandibular incisors; (2) pre-surgical alignment, leveling, and space closure of the teeth in both arches, and protraction of the second maxillary molars to close the maxillary space; (3) surgical treatment including a LeFort I osteotomy for maxillary retraction and rotation, a bilateral sagittal split osteotomy for mandibular advancement and rotation, and a genioplasty for correctting the skeletal deformities; and (4) post-surgical correction of the malocclusion. CONCLUSION: The patient's facial esthetics was significantly improved and a desirable occlusion was achieved after 16 mo treatment. Follow-up records after 2 years showed stable esthetics and function.

Spontaneous healing of complicated crown-root fractures in children: Two case reports.

BACKGROUND: Complicated crown-root fracture is considered a severe dental trauma and is unlikely to heal without treatment. Usually, dentists have to remove the loose coronal fragment of the fractured tooth and treat the remaining part with multidisciplinary approaches. However, we observed spontaneous healing of fracture in two pediatric cases with a history of complicated crown-root fractures over 4 years ago. CASE SUMMARY: In case 1, a 12-year-old boy complained of pain at tooth 11 following an accidental fall 1 d ago. Clinical examination showed a crack line on the crown of tooth 11. Cone beam computed tomography (CBCT) images of tooth 11 showed signs of hard tissue deposition between the fractured fragments. The patient recalled that tooth 11 had struck the floor 1 year ago without seeking any other treatment. In case 2, a 10-year-old girl fell down 1 d ago and wanted to have her teeth examined. Clinical examination showed a fracture line on the crown of tooth 21. CBCT images of tooth 21 also showed signs of hard tissue deposition between the fractured fragments. She also had a history of dental trauma 1 year ago and her tooth 11 received dental treatment by another dentist. According to her periapical radiograph at that time, tooth 21 was fractured 1 year ago and the fracture was overlooked by her dentist. Both of these two cases showed spontaneous healing of complicated crown-root fractures. After over 4 years of follow-up, both fractured teeth showed no signs of abnormality. CONCLUSION: These findings may provide new insights and perspectives on the management and treatment of crown-root fractures in children.

Tracheobronchial intubation using flexible bronchoscopy in children with Pierre Robin sequence: Nursing considerations for complications.

BACKGROUND: It has been shown that children with Pierre Robin sequence (PRS) have a higher risk of difficult intubation before surgery. When mask ventilation or tracheobronchial intubation is expected to be challenging, flexible bronchoscopy (FB) is advantageous in airway safety when it is used to guide tracheobronchial intubation (TI). AIM: To evaluate the complications of TI using FB in children with PRS and explore the effect of nursing services on postoperative complications. METHODS: One hundred and five children with PRS underwent TI using FB before early mandibular distraction osteogenesis. One hundred and eight children with common pneumonia who did not have a difficult airway were set as the control group. Demographic data, success rates of TI, time required for TI, number of TI attempts, and the incidence of postoperative complications were assessed. Besides, the strategies used to attenuate complications were investigated. RESULTS: The success rate of TI was 100% in children with PRS, while the success rate at the first attempt in the PRS group was significantly lower than that in the control group (88.6% vs 98.2%, P = 0.005). The time required for TI in the PRS group was markedly longer than that in the control group (P < 0.001). Children in the PRS group required repetitive operations to enter the glottis successfully (P = 0.017). The incidence of complications was noticeably higher in the PRS group (50/105, 47.6%) than in the control group (36/108, 33.3%) (P = 0.034). Seven of 105 PRS children experienced laryngeal edema (LE) (6.7%), compared with one (0.9%) in the control group (P = 0.034). Out of the seven patients who had LE, all were reintubated and managed with steroids: six recovered with inhaled steroids alone before extubated, and one was given systemic corticosteroids before recovery. CONCLUSION: FB contributes to a high success rate of TI in children with PRS. To prevent LE, operators should pay more attention to catheter material, catheter lubrication and intubation time.

Influence of biofilms on the adsorption behavior of nine organic emerging contaminants on microplastics in field-laboratory exposure experiments.

Microplastics (MPs) are ubiquitous in aquatic environments, which are important carriers of emerging contaminants (ECs). Biofilms can be attached to the surface of MPs in a natural aquatic environment, which may influence chemical adsorption; however, knowledge of its impact is still limited. This study investigated the effect of biofilms on MPs on the adsorption of ECs through field-laboratory exposure experiments. Three types of MPs were naturally colonized with biofilms in lake. Then, biofilm-absent/biofilm-attached MPs were exposed to nine EC solutions at a concentration of 8 µg/L of each compound in laboratory. Most compounds exhibited 3.8 times lower concentrations on biofilm-attached MPs than on biofilm-absent MPs; only a few compounds showed enhanced adsorption. Pseudo-equilibrium was achieved within 72 h based on adsorption kinetics, implying fast adsorption of ECs on biofilm-attached MPs. The partition coefficients (Kd) for biofilm-attached MPs were 0.14 (diclofenac) to 535 (miconazole) L/kg and were positively correlated with octanol/water partition coefficients (Kow). This indicated that chemical properties (such as Kow) of the compounds determined their final adsorption amounts on MPs, although these were influenced by the presence of the biofilm. Hence, multiple influencing factors should be considered when evaluating the carrier potential of MPs for ECs in aquatic environments.

The pharmacokinetic and pharmacodynamic properties and short-term outcome of a novel once-weekly PEGylated recombinant human growth hormone for children with growth hormone deficiency.

Objectives: To investigate the pharmacokinetics (PK) and pharmacodynamics (PD) of Y-shape branched PEGylated recombinant human growth hormone (YPEG-rhGH) and evaluate its short-term efficacy and safety in children with growth hormone deficiency (GHD). Methods: A total of 43 children with GHD from 12 sites in China were enrolled in this randomized, multicenter, active-controlled, double-blind (YPEG-rhGH doses) trial. Patients were randomized 1:1:1:1 to 100, 120, and 140 µg/kg/week of YPEG-rhGH groups and daily rhGH 35 µg/kg/day groups. The treatment lasted 12 weeks. The primary outcome was the area under the curve of the change of insulin-like growth factor-1 (IGF-1). The secondary outcome was the height velocity (HV) increment at week 12. Results: A dose-dependent response of maximum plasma concentration (Cmax) and area under the concentration-time curves from 0 to 168 hours (AUC0-168h) were observed for YPEG-rhGH. The ratio of Cmax and the ratio of AUC0-168h from the first to the last dosing were 1.09~1.11 and 1.22~1.26 respectively. A YPEG-rhGH dose-dependent increase in area under effect curve (AUEC) of IGF-1 fold change was observed. Model-derived mean IGF-1 SDS was in the normal range for all three YPEG-rhGH doses. At week 12, HV was 7.07, 10.39, 12.27 cm/year, and 11.58 cm/year for YPEG-rhGH 100, 120, and 140 µg/kg/week and daily rhGH respectively. Adherence and safety were consistent with the profile of daily rhGH. No related serious adverse events were reported. Conclusion: The PK/PD suggests that YPEG-rhGH is suitable for the once-weekly treatment of pediatric GHD. YPEG-rhGH 120 ~ 140 µg/kg/week provides the closest HV increment with similar safety and tolerability compared to daily rhGH 35 µg/kg/day in children with GHD. Clinical Trial Registration: ClinicalTrials.gov, identifier [NCT04513171].

Enterovirus 71 Antagonizes Antiviral Effects of Type III Interferon and Evades the Clearance of Intestinal Intraepithelial Lymphocytes.

Enterovirus 71 (EV71) is the major pathogen causing severe neurological complications and hand, foot, and mouth disease. The intestinal mucosal immune system has a complete immune response and immune regulation mechanism, consisting of densely arranged monolayer intestinal epithelial cells (IECs) and intestinal intraepithelial lymphocytes (iIELs) distributed among the IECs, which constitute the first line of intestinal mucosa against infection of foreign pathogens. As an enterovirus, EV71 is transmitted by the intestinal tract; however, the mechanisms it uses to evade the immunosurveillance of the intestinal mucosal immune system are still incompletely clarified. The present study investigated how EV71 evades from recognizing and eliminating IECs, iIELs, and iNK cells. We found that EV71 infection induced a higher level of type III interferons (IFN-λ) than type I interferons (IFN-ß) in IECs, and the addition of IFN-λ markedly restricted EV71 replication in IECs. These results indicate that IFN-λ plays a more important role in anti-EV71 intestinal infection. However, EV71 infection could markedly attenuate the antiviral responses of IFN-λ. Mechanistically, 2A protease (2Apro) and 3C protease (3Cpro) of EV71 inhibited the IFN-λ production and IFN-λ receptor expression and further decreased the response of IECs to IFN-λ. In addition, we found that EV71-infected IECs were less susceptible to the lysis of intestinal NK (iNK) cells and CD3+iIELs. We revealed that the viral 2Apro and 3Cpro could significantly reduce the expression of the ligands of natural killer group 2D (NKG2D) and promote the expression of PD-L1 on IECs, rendering them to evade the recognition and killing of iNK and CD3+iIELs. These results provide novel evasion mechanisms of EV71 from intestinal mucosal innate immunity and may give new insights into antiviral therapy.

Release Strategies of Silver Ions from Materials for Bacterial Killing.

Silver-based antibacterial agents have attracted much attention in biomedical fields owing to their high antibacterial activity. Silver ions (Ag+) play a significant role in killing bacteria because they can readily adsorb to most biomolecules (DNA, membrane protein, enzymes, or intracellular cofactors) in bacteria to inactivate their functions. In this review, recent advances in the ways of Ag+ release from silver-contained materials were discussed. As a start, the antibacterial mechanisms of Ag+ was summarized. Then, the release strategies of Ag+ from silver-carrying materials have been categorized into two types: (1) passive release and (2) stimuli-responsive release. In particular, the stimuli-responsive materials relying on either endogenous or exogenous stimuli have been rationally designed for eliminating bacteria with high efficacy and selectivity. Future studies should focus on enhancing the controllability of Ag+ release in the infected sites of the human organs.

Novel truncating variant of PPM1D penultimate exon in a Chinese patient with Jansen-de Vries syndrome.

BACKGROUND: Jansen-de Vries syndrome is a rare autosomal dominant neurodevelopmental disorder caused by pathogenic variants in the last and penultimate exons of the PPM1D gene. It is characterized by delayed psychomotor development, intellectual disability with speech delay, behavioral abnormalities, and dysmorphic features. Up to date, only 17 affected patients have been reported worldwide (no report in Chinese). METHODS: Here, we analyzed the clinical data and genetic test results of a Chinese patient with Jansen-de Vries syndrome admitted in our hospital in May 2019. RESULTS: We report a 9-month-old boy carrying a pathogenic variant (c.1254_1255del, p.(V419Qfs*14)) in PPM1D exon 5, which can account for his phenotype. Most of his clinical features overlap with the reported phenotype, such as growth retardation, feeding difficulties, constipation, congenital abnormalities (such as atrial septal defect, ventricular septal defect, and patent ductus arteriosus), small hands and feet with broad forehead, low-set posteriorly rotated ears, wide mouth with thin upper lip and pointed chin; however, he also presented with additional features like hepatomegaly and left inguinal hernia. CONCLUSION: This is the first published case of Jansen-de Vries syndrome in Chinese population, which will help us to enrich the clinical spectrum of this syndrome.

Meta-analysis dataset comparing orthodontic mini-implants and conventional anchorage reinforcement for maximum orthodontic anchorage.

The present article describes data from systematic review and meta-analysis investigating the efficacy and safety outcomes comparing mini-implants (MIs) and conventional anchorage reinforcement in patients with maximum dentoalveolar protrusion. All relevant RCTs and non-RCTs published up to 2018 were collected from PubMed, Embase and Cochrane database. Thirteen studies assessing the effect of mini-implants were included, of which 4 were randomized controlled trials (RCTs) and 9 observational studies. The efficacy parameters include mesiodistal movements of molars and incisors and vertical movements of molars and incisors. Whereas, the safety parameters were angular and linear measurement of soft tissue change. Subgroup analysis data was provided in terms of patients average age (<18 years and ≥18 years) at the initiation of treatment. This dataset is suitable for research purpose in the field of orthodontics and also helps dental doctors to determine their treatment preferences in the choice of anchorage reinforcement.

Effect of Poly(ethylene glycol) (PEG) Surface Density on the Fate and Antitumor Efficacy of Redox-Sensitive Hybrid Nanoparticles.

The effects of poly(ethylene glycol) (PEG) on improving the biological compatibility and circulation time of nanocarriers are determined by the surface density of PEG on nanoparticles. PEG with high surface density on nanocarriers has greater accumulation in tumor tissues. However, this impairs the release of drugs loaded in the nanoparticles in the tumor tissues. The relations and internal regularities between the controlled stripping of PEG of nanoparticles and its fate and antitumor efficacy in vivo remain unsolved. Redox-sensitive hybrid nanoparticles coated with varied PEG densities were prepared by blending a redox-sensitive polymer of DLPE-SS-MPEG. To keep identical nanoproperties, these nanoparticles were prepared with a similar size distribution of around 100 nm. The effects of controlled stripping of PEG on antitumor activities of nanoparticles were then investigated. As the PEG surface density increased, lower cellular internalization by tumor cells was observed. However, nanoparticles with higher controlled stripping of PEG showed greater accumulation in tumor tissues and advanced antitumor activities in vivo.

In Situ Fabrication of Intelligent Photothermal Indocyanine Green-Alginate Hydrogel for Localized Tumor Ablation.

Simplifying synthesis and administration process, improving photothermal agents' accumulation in tumors, and ensuring excellent biocompatibility and biodegradability are keys to promoting the clinical application of photothermal therapy. However, current photothermal agents have great difficulties in meeting the requirements of clinic drugs from synthesis to administration. Herein, we reported the in situ formation of a Ca2+/Mg2+ stimuli-responsive ICG-alginate hydrogel in vivo for localized tumor photothermal therapy. An ICG-alginate hydrogel can form by the simple introduction of Ca2+/Mg2+ into ICG-alginate solution in vitro, and the widely distributed divalent cations in organization in vivo enabled the in situ fabrication of the ICG-alginate hydrogel without the leakage of any agents by simple injection of ICG-alginate solution into the body of mice. The as-prepared ICG-alginate hydrogel not only owns good photothermal therapy efficacy and excellent biocompatibility but also exhibits strong ICG fixation ability, greatly benefiting the high photothermal agents' accumulation and minimizing the potential side effects induced by the diffusion of ICG to surrounding tissues. The in situ-fabricated ICG-alginate hydrogel was applied successfully in highly efficient PTT in vivo without obvious side effects. Besides, the precursor of the hydrogel, ICG and alginate, can be stored in a stable solid form, and only simple mixing and noninvasive injection are needed to achieve PTT in vivo. The proposed in situ gelation strategy using biocompatible components lays down a simple and mild way for the fabrication of high-performance PTT agents with the superiors in the aspects of synthesis, storage, transportation, and clinic administration.

[Prevalence of dental caries and associated factors among 10-12-year-old students in Chongqing].

OBJECTIVE: To investigate the caries status of the first permanent molars in urban and rural children aged 10-12 in Chongqing and analyze the related factors in order to provide a theoretical basis for the prevention and treatment of children's caries and targeted suggestions for oral health education. METHODS: A multi-stage, stratified, cluster, and random sampling method was used to extract 5 057 children from 18 schools in three districts and three counties in Chongqing for oral health examination and questionnaire survey from March to May 2018. RESULTS: The total caries rate of the first permanent molar was 39.2%. The decayed-missing-filled tooth was 0.84±1.20. The rate of filling teeth was 3.4%. The rate of pit and fissure sealing was 6.1%. The prevalence of the first permanent molars was significantly different between men and women, between urban and rural areas, between only children and non-only children, and between ethnic minorities and Han nationality (P<0.001). The gap between the pit and fissure sealing was significantly different between urban and rural areas (P<0.001). Multiple logistic regression analysis showed that many independent factors influence the occurrence of caries, including the frequency of brushing teeth every day, the frequency of eating desserts, the habit of eating dessert/drinking milk before going to bed, whether only-children or not, and parents' education background, among others. CONCLUSIONS: The first permanent molars of children aged 10-12 in Chongqing have a high rate of caries but low rates of pit and fissure sealing and dental caries filling. The difference between urban and rural areas is large, children's oral health knowledge is scarce, and children have bad oral hygiene behaviors and eating habits. Children's oral health education must be strengthened, oral health preaching must be implemented in schools, the oral health knowledge of children in school must be improved, and urban-rural differences must be minimized.

Microwave-assisted ultrafast fabrication of high-performance polypyrrole nanoparticles for photothermal therapy of tumors in vivo.

Photothermal therapy with minimal invasiveness and high selectivity has been regarded as a powerful technique for tumor therapy to overcome the risks of toxic side effects and limited therapeutic efficacy of clinic cancer treatments. Among various photothermal therapeutic agents, polypyrrole (PPy) nanoparticles show a promising prospect in tumor ablation in vivo due to their admirable biocompatibility and outstanding photothermal performance. Besides, polypyrrole nanoparticles are extensively applied in biosensors, electrochemical sensors, tissue engineering, flexible microelectronics, and so on. However, the available synthesis methods of PPy nanoparticles are all time-consuming and seriously hindered their highly efficient production for diverse applications. Here we present a microwave-assisted strategy for the fabrication of PPy nanoparticles in 2 min, and the required synthesis time is shortened by 120-720 times compared to that in traditional ways. The prepared PPy nanoparticles possess uniform size, favorable aqueous solubility, and enhanced photothermal performance derived from the stronger near-infrared absorbance. Low cytotoxicity and in vivo toxicity of the nanoparticles were confirmed via comprehensive assessments. The PPy nanoparticle-based photothermal therapy in vitro led to a remarkable death of tumor cells, and in vivo tumor ablation using the nanoparticles was achieved under mild laser irradiation with a FDA-approved safe power. The proposed microwave-assisted synthesis strategy opens up a facile and ultrafast way for the construction of organic nanoparticles and facilitates a wide range of applications of them in biomedicine and other fields.