ERS Mediated by GRP-78/PERK/CHOP Signaling Is Involved in Fluoride-Induced Ameloblast Apoptosis.

Fluoride can be widely ingested from the environment, and its excessive intake could result in adverse effects. Dental fluorosis is an early sign of fluoride toxicity which can cause esthetic and functional problems. Though apoptosis in ameloblasts is one of the potential mechanisms, the specific signal cascade is in-conclusive. High-throughput sequencing and molecular biological techniques were used in this study to explore the underlying pathogenesis of dental fluorosis, for its prevention and treatment. A fluorosis cell model was established. Viability and apoptosis rate of mouse ameloblast-derived cell line (LS8 cells) was measured using cell counting kit-8 (CCK-8) assay and flow cytometry analysis. Cells were harvested with or without 2-mM sodium fluoride (NaF) stimulation for high-throughput sequencing. Based on the sequencing data, subcellular structures, endoplasmic reticulum stress (ERS), and apoptosis related biomarkers were verified using transmission electron microscopy, quantitative real-time polymerase chain reaction, and Western blotting techniques. Expression of ERS markers, apoptosis related proteins, and enamel formation enzymes were detected using Western blotting after addition of 4-phenylbutyrate (4-PBA). NaF-inhibited LS8 cells displayed time- and dose- dependent viability. Additionally, apoptosis and morphological changes were observed. RNA-sequencing data showed that protein processing in endoplasmic reticulum was obviously affected. ERS and apoptosis were induced by excessive NaF. Downregulation of kallikrein-related peptidase 4 (KLK4) was also observed. Inhibition of ERS by 4-PBA rescued the apoptotic and functional protein changes in cells. Excessive fluoride induces apoptosis by activating ERS, which is mediated by GRP-78/PERK/CHOP signaling. Key proteinase is present in maturation-stage enamel; KLK4 was also affected by fluoride, but rescued by 4-PBA. This study presents a possibility for therapeutic strategies for dental fluorosis, while further exploration is required.

Effects of Gender and Maneuvers on ACL Injury Risk Factors for Volleyball Players / 医用生物力学

Objective To study the effect of gender and maneuvers on anterior cruciate ligament (ACL) injury risk factors for volleyball players. Methods Sports biomechanics data of volleyball players during stop-jump, drop landing and sidestep cutting were collected. The ACL injury rate and biomechanical parameters of simulated injured jumps were obtained with Monte Carlo simulation. The influence of gender and maneuvers on ACL injury risk factors was validated by 2×3 mixed designed two-way ANOVA. Results Sidestep cutting was the highest risk maneuver of ACL injury for both genders (P＜0.001). Compared with male players, female players had a greater risk of ACL injury during sidestep cutting and stop-jump (P＜0.001), while male players were more prone to have ACL injury than female players during drop landing (P＜0.001). The risk factors of ACL injury obtained by simulation were significantly influenced by gender and maneuvers (P＜0.001). Conclusions Male players were more likely to increase ACL load due to smaller knee flexion, forward leg tilt and heel landing than female players during sidestep cutting, while female players owned larger ground reaction force (GRF) and knee extension moment. Smaller knee flexion angle during stop jump was the major risk factor for both genders, however more characteristics contributed to the males. Female players with large GRF, knee valgus and extension moment, and heel-landing were likely to have ACL injury, while the small knee flexion angle was the key risk factor for male players. The results can provide evidences for evaluation of volleyball players’ ACL injury risk, individualized injury prevention protocols, and clinical treatment and rehabilitation directions.

210Po distribution after high temperature processes in coal-fired power plants.

In this paper, the distribution of 210Po after high temperature processes in six units of coal-fired power plants (CFPs) were evaluated. The coal, bottom ashes, fly ashes from electrostatic precipitators (ESP), and flue gases from stacks were sampled from four CFPs and analyzed for 210Po contents. The results showed that 210Po was mainly captured by the ESP, with little left in the bottom ash, and a small fraction of 210Po was directly discharged into the environment through the stacks, accounting for 0.06%-0.6%, which was consistent with the reported data. It was also found that part of the 210Po could not be accounted for in the mass balance analysis for the whole combustion process in CFPs, which was also in line with the reported data. The results obtained in this study provided essential basic data for environmental radiological risk analysis for CFPs.

Effect of casein phosphopeptide-amorphous calcium phosphate on the stability of resin-dentin bonds against pH cycling / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on the stability of resin-dentin bonds against pH cycling.</p><p><b>METHODS</b>Resin-bonded dentin specimens were prepared following manufacturers' instructions, and randomly divided into 3 groups. Among them, 2 groups experienced pH cycling, in which specimens applied CPP-ACP or distilled and deionized water (DDW) on the bonding interface, respectively. Microtensile bond strength (muTBS) testing, failure mode analysis, micromorphological and nanoleakage evaluation of bonding interface and elemental analysis within hybrid layer were performed after 15 days pH cycling. The other group was tested immediately after specimens' preparation without pH cycling.</p><p><b>RESULTS</b>No significant differences were found in muTBS between no pH cycling and pH cycling/CPP-ACP group. Their muTBS were both significantly higher than that of pH cycling/DDW group (P < 0.05). Mixed fractures were the most prevalent failure mode. The quality of hybrid layer in pH cycling/CPP-ACP group was better than that of pH cycling/DDW group, and the nanoleakage was also less severe. Comparing with pH cycling/DDW group, the atomic percentages of Ca in the other two groups were both significantly higher, while those of Ag were statistically lower (P < 0.05).</p><p><b>CONCLUSION</b>Local application of CPP-ACP can promote the stability of resin-dentin bonding interface against pH cycling and prolong bonding degeneration.</p>

Study on evaluating dose to fishes based on its anatomic model.

Here, an anatomic model of mullet is developed on sampling, dissection, and measurement on site. A Monte Carlo code is used to compute the energy-absorbed fraction in tissues and organs of the mullet, and dose rates are calculated. Some previous methods are selected for comparison. The results calculated by means of a newly developed anatomic model indicate that the dose rate to each tissue/organ is different, and dose rates to some tissues/organs are much larger than those calculated based on previous uniform models. This suggests that it is necessary to exploit an anatomic model if there are various concentration factors within the organism. Taking the organism as a whole, the anatomic model has smaller internal dose rates and middle external dose rates among these methods.