Microplastics in the Coral Reef Systems from Xisha Islands of South China Sea.

The impacts of microplastics on coral reefs are gaining attention due to findings that microplastics affect coral health. This work investigated the distribution and characteristics of microplastics in the seawater, fish, and corals in 3 atolls from the Xisha Islands of South China Sea. In the seawater samples, microplastics were detected in the outer reef slopes, reef flats, and lagoons with abundances ranging from 0.2 to 11.2, 1.0 to 12.2, and 1.0 to 45.2 items L-1, respectively. Microplastic abundance was 0-12.0 items individual-1 (0-4.7 items g-1) in fish and 1.0-44.0 items individual-1(0.02-1.3 items g-1) in coral. The predominant shape and polymer of microplastics in seawater, fish, and coral were fibrous rayon and polyethylene terephthalate (PET). Microplastic sizes primarily ranged from 20-330 µm in both the seawater and fish, while there were relatively more 1-5 mm microplastics in the corals. The shape, size, color, and polymer type distribution patterns of microplastics in seawater more closely resembled those in fish gills than those in fish gastrointestinal tracts or coral samples. This study shows that microplastics are abundant in these coral reef systems and they are captured by fish or "trapped" by corals.

The Role of MicroRNA-143-5p in the Differentiation of Dental Pulp Stem Cells into Odontoblasts by Targeting Runx2 via the OPG/RANKL Signaling Pathway.

This study aims to elucidate the mechanisms by which microRNA-143-5p (miR-143-5p) targets runt-related transcription factor 2 (Runx2) in the differentiation of dental pulp stem cells (DPSCs) into odontoblasts, through regulating the osteoprotegerin receptor activator of the nuclear factor-κB ligand (OPG/RANKL) signaling pathway. Following transfection, DPSCs were divided into blank, control, miR-143-5p mimics, miR-143-5p inhibitors, miR-143-5p inhibitors + siRunx2 and siRunx2 groups. Alkaline phosphatase (ALP) activity and mineralized nodules were detected using ALP kit and alizarin red staining. Quantitative reverse transcriptase real time PCR (qRT-PCR) was conducted to measure mRNA expressions of miR-143-5p, Runx2, OPG, and RANKL. Western blotting was used to assess protein expression of odontoblast differentiation-related proteins. Transwell assay and an extracellular matrix (ECM) adhesion cell assay were employed to examine cell migration and cell adhesion. Compared with the blank group, the miR-143-5p mimics and siRunx2 groups showed decreased ALP activity, decreased mineralized nodules and displays of calcium. Fewer migrated cells, weakened cell adhesion, decreased protein expression of dentin phosphoprotein (DPP), dentin sialoprotein (DSP), dentin matrix protein 1 (DMP1), osteopontin (OPN), bone sialoprotein (BSP), osteocalcin (OCN), OPG and Runx2, and increased RANKL protein expressions were observed. Additionally, opposite results were observed in the miR-143-5p inhibitors group, demonstrating that down-regulated miR-143-5p promotes the differentiation of DPSCs into odontoblasts by enhancing Runx2 expression via the OPG/RANKL signaling pathway. Based on findings in this study, it is postulated that the enhancement of Runx2 expression via the regulation of the OPG/RANKL signaling pathway could be a beneficial approach for dental pulp regeneration. J. Cell. Biochem. 119: 536-546, 2018. © 2017 Wiley Periodicals, Inc.

Effects of different fermentation methods on bacterial cellulose and acid production by Gluconacetobacter xylinus in Cantonese-style rice vinegar.

A strain of acidogenic bacterium was isolated from the fermentation liquid of Cantonese-style rice vinegar produced by traditional surface fermentation. 16S rDNA identification confirmed the bacterium as Gluconacetobacter xylinus, which synthesizes bacterial cellulose, and the acid productivity of the strain was investigated. In the study, the effects of the membrane integrity and the comparison of the air-liquid interface membrane with immerged membrane on total acidity, cellulose production, alcohol dehydrogenase (ADH) activity and number of bacteria were investigated. The cellulose membrane and the bacteria were observed under SEM for discussing their relationship. The correlations between oxygen consumption and total acid production rate were compared in surface and shake flask fermentation. The results showed the average acid productivity of the strain was 0.02g/(100mL/h), and the integrity of cellulose membrane in surface fermentation had an important effect on total acidity and cellulose production. With a higher membrane integrity, the total acidity after 144 h of fermentation was 3.75 g/100 mL, and the cellulose production was 1.71 g/100 mL after 360 h of fermentation. However, when the membrane was crushed by mechanical force, the total acidity and the cellulose production were as low as 0.36 g/100 mL and 0.14 g/100 mL, respectively. When the cellulose membrane was forced under the surface of fermentation liquid, the total acid production rate was extremely low, but the activity of ADH in the cellulose membrane was basically the same with the one above the liquid surface. The bacteria were mainly distributed in the cellulose membrane during the fermentation. The bacterial counts in surface fermentation were more than in the shake flask fermentation and G. xylinus consumed the substrate faster, in surface fermentation than in shake flask fermentation. The oxygen consumption rate and total acid production rate of surface fermentation were respectively 26.13 times and 2.92 times that of shake flask fermentation.

[Advance in studies on antioxidant activity of propolis and its molecular mechanism].

Propolis is an adhesive substance mixed with plant resins collected by honeybees (Apis mellifera) and secretions from their mandibular gland and wax gland, with wide pharmacological activity and healthcare functions. Its antioxidant activity has long been regarded as one of the most important biological activities of propolis. This article summarizes studies on the antioxidant activity of propolis extracts from different geographic origins and with different extraction methods, as well as several important monomer active ingredients in propolis, and concludes the potential molecular mechanism of antioxidant activity of propolis and its monomer ingredients, with the aim of providing ideas for further studies on pharmacological activity of propolis, as well as reference for in-depth development of propolis products.

High-rate anaerobic decolorization of methyl orange from synthetic azo dye wastewater in a methane-based hollow fiber membrane bioreactor.

Anaerobic biological techniques are widely used in the reductive decolorization of textile wastewater. However, the decolorization efficiency of textile wastewater by conventional anaerobic biological techniques is generally limited due to the low biomass retention capacity and short hydraulic retention time (HRT). In this study, a methane-based hollow fiber membrane bioreactor (HfMBR) was initially inoculated with an enriched anaerobic methane oxidation (AOM) culture to rapidly form an anaerobic biofilm. Then, synthetic azo dye wastewater containing methyl orange (MO) was fed into the HfMBR. MO decolorization efficiency of ∼ 100 % (HRT = 2 to 1.5 days) and maximum decolorization rate of 883 mg/L/day (HRT = 0.5 day) were obtained by the stepwise increase of the MO loading rate into the methane-based HfMBR. Scanning electron microscopy (SEM) and fluorescence in situ hybridization (FISH) analysis visually revealed that archaea clusters formed synergistic consortia with adjacent bacteria. Quantitative PCR (qPCR), phylogenetic and high-throughput sequencing analysis results further confirmed the biological consortia formation of methane-related archaea and partner bacteria, which played a synergistic role in MO decolorization. The high removal efficiency and stable microbial structure in HfMBR suggest it is a potentially effective technique for high-toxic azo dyes removal from textile wastewater.

Royal jelly attenuates nonalcoholic fatty liver disease by inhibiting oxidative stress and regulating the expression of circadian genes in ovariectomized rats.

Nonalcoholic fatty liver disease (NAFLD) has a high incidence in postmenopausal women and is accompanied by insulin resistance, obesity, and dyslipidemia. Royal jelly (RJ), a natural substance derived from hive, possesses numerous health-beneficial properties. Here, we evaluated the effects of RJ (150, 300, and 450 mg kg-1  day-1 , 8 weeks) on NAFLD in ovariectomized (OVX) rats. Based on the results, RJ ameliorated the degree of anxiety, improved serum lipid profile, and attenuated the hepatic steatosis and liver injury in OVX rats. Furthermore, the protective effects of RJ could be attributed to its antioxidant properties, which enhance the levels of hepatic antioxidant enzymes. The qRT-PCR results also suggest that RJ improves the disturbances of circadian genes by downregulating their expression, including that of Per1 and Per 2, in the liver of OVX rats. Altogether, our findings suggest that RJ may be a promising agent for the treatment of NAFLD. PRACTICAL APPLICATIONS: Postmenopausal women are at an increased risk of NAFLD. Currently, there are no licensed therapies for NAFLD. Although hormone replacement therapy (HRT) is reported to inhibit the development of NAFLD, it causes unexpected adverse effects. As HRT is controversial, the use of natural supplements to counteract the detrimental effects of menopause has recently attracted more attention. RJ is a natural product secreted from the hypopharyngeal and mandibular glands of worker bees. The present study illustrates the protective effect of the natural product, RJ, and its underlying mechanisms on NAFLD. This is the first study to assess the effect of RJ on NAFLD under estrogen deficiency. Such findings contribute to the further utilization of RJ, which might serve as a promising therapeutic option and natural food for the treatment of NAFLD.

[Application of Flipped classroom combined with case-based learning in resident training of endodontics].

PURPOSE: To apply Flipped classroom combined with case-based learning(CBL) in resident training of endodontics, in order to improve training efficiency. METHODS: Fifty-one residents from China Medical University, School of Stomatology were randomly divided into 2 groups, twenty-six students in the experimental group were trained with Flipped classroom combined with CBL, the other twenty-five students in the control group were trained with traditional teaching method. At the end of the course, exams and questionnaires were conducted to evaluate the training quality of two different methods. The exams consisted of didactic and operational assessment. The data were analyzed with SPSS 13.0 software package. RESULTS: The results of didactic exam and comprehensive evaluation indicated that experimental group was significantly higher than the control group(P<0.05). The results of questionnaires indicated that residents showed much more satisfied with Flipped classroom combined with CBL (P<0.05).However, there was no significant difference in operational assessment(P>0.05). CONCLUSIONS: Compared with traditional teaching method, Flipped classroom combined with CBL can achieve better training effect, which is worthy of further application in dental resident training.

[Application of micro-lecture in standardized training of endodontic residents].

PURPOSE: To apply micro-lecture in standardized training of endodontic residents, in order to improve training quality. METHODS: Twenty endodontic residents were randomly divided into 2 groups, 10 students in each group. One group were taught with micro-lecture while the other group with lecture-based learning (LBL). The teaching effect was measured with examination and questionnaire survey. The examination results were analyzed by Student's t test using SPSS 18.0 software package. RESULTS: Micro-lecture group was better than LBL group in practical test and total scores, there were significant differences between the two groups (P＜0.05). Micro-lecture group was better than LBL group in didactic test, but there was no significant difference between the two groups (P＞0.05). Questionnaire survey showed that micro-lecture was well accepted by residents for its novelty and flexibility, self-motivated learning ability was trained, communication between teachers and residents was enhanced, but the production level of micro-lecture video needs to be improved. CONCLUSIONS: Micro-lecture achieves satisfactory teaching effect, and can be applied in standardized training of endodontic residents.

Hollow fiber membrane bioreactor affects microbial community and morphology of the DAMO and Anammox co-culture system.

Denitrifying anaerobic methane oxidation (DAMO) and Anammox co-culture system was investigated in hollow fiber membrane bioreactor (HfMBR) for the change of microbial community morphology and proportion. NO3--N and NH4+-N removal rates reached 85.33 and 37.95mg/L/d on 193d. The inoculum microorganisms were flocs and the proportion of DAMO archaea, DAMO bacteria and Anammox bacteria was 11.0, 24.2 and 0.4%, respectively, but it changed to 74.3, 11.8, 5.6% in HfMBR, respectively. Interestingly, microorganisms formed biofilms on fibers surface and the biofilms included two layers: inner layer was thin and dominated by DAMO bacteria and Anammox bacteria; while the outer layer was thick made up of granules with 100-200µm diameter and dominated by DAMO archaea. The spatial distribution of microorganisms in HfMBR was different from simulation results in the literature. Likely, HfMBR changed the interaction between DAMO and Anammox microorganisms, and the reactor configuration was beneficial for DAMO archaea growth.

[Application of PBL combined with SP method in during-course practice of endodontics for undergraduate dental students].

PURPOSE: To apply problem-based learning (PBL) combined with standardized patients(SP) in during-course practice of endodontics for undergraduate dental students, in order to improve the teaching quality. METHODS: One hundred and four undergraduate dental students of China Medical University School of Stomatology were randomly divided into 2 groups, 52 students in each group. One group were taught with PBL combined with SP while the other group with lecture-based learning (LBL) alone. The teaching effect was measured with examination and questionnaire survey. The data were analyzed by Student's t test using SPSS 11.5 software package. RESULTS: Students in PBL combined with SP group was better than LBL group in case analysis, didactic tests, practical tests and total scores, and there was significant difference between the two groups (P<0.05). LBL group was better than PBL combined with SP group in basic theoretical knowledge scores, and there was significant difference between the two groups (P<0.05). SP and PBL combined with SP method were welcomed by undergraduate dental students. CONCLUSIONS: The abilities of undergraduate dental students can be improved by PBL combined with SP in different aspects. PBL combined with SP achieves satisfactory teaching effect, and can be applied in during-course practice of endodontics to undergraduate dental students.

[The effect of calcium hydroxide on IL-6 and TNF-α expression of osteoblast in periapical tissues].

PURPOSE: To compare the effect of calcium hydroxide in different position on pH and inflammation factor expression of periapical osteoblasts. METHODS: 140 sterilized single-rooted human teeth models were randomly divided into 6 experiment groups and one control group: Group 1-3:calcium hydroxide paste was placed in the apical half of root canal, the upper half of root canal and the pulp champer; Group 4-6:Apexcal was placed in the apical half of root canal, the upper half of root canal and the pulp champer; Group 7: the control group without medication. 10 teeth of each group were placed in P.e suspension, the IL-6 and TNF-α expression of MC3T3-E1 was tested at 3 d and 7 d. The other teeth of each group were placed in distilled water, and the pH in periapical region was tested at 3, 7, 14 and 21 d. SPSS 13.0 software package was used for statistical analysis. RESULTS: Calcium hydroxide placed in different position of the root canal increased periapical pH value and reached its peak at 14 d. The group in which calcium hydroxide paste was placed in pulp chamber gained lower pH level than other experimental groups. IL-6, TNF-α expression of MC3T3-E1 pretreated by P.e suspension of experimental groups was significantly reduced compared with control group, and there was no significant difference between the experimental groups. CONCLUSIONS: Calcium hydroxide placed in different position of the root canal could increase periapical pH value and reduce IL- 6, TNF-α expression of periapical osteoblasts.

[Comparison of wear resistance and flexural strength of three kinds of bulk-fill composite resins].

PURPOSE: To compare the abrasion resistance and flexure strength of three bulk-fill resin composites with an universal nano-hybrid composite resins. METHODS: The specimens were prepared with three kinds of bulk fill composites (SDR , sonicfill, Tetric N-Ceram Bulk Fill) and an universal nano-hybrid composite resins(Herculite Precis). 10 mm in diameter × 2mm in height specimens were prepared for abrasion resistance, while 2 mm in width × 2 mm in depth×25 mm in length specimens were prepared for flexure strength. The specimens were mounted in a bal1-on-disc wear testing machine and abraded with the media artificial saliva(50 N loads, 10000 cycles).Flexural test was performed with an Universal Testing Machine at a cross-head speed of 1mm/min. One-way variance analysis was used to determine the statistical differences of volume loss and flexural strength among groups with SPSS 13.0 software package(P<0.05). RESULTS: The volume loss was as follows: SDR (1.2433±0.11) mm30.05). CONCLUSIONS: With regard to wear resistance and flexural strength, Tetric N-Ceram Bulk Fill is recommended as an alternative for posterior restorations.

Effect of one versus two distal locking bolts on the biomechanics of tibial interlocking nail: a comparative study using a new model.

OBJECTIVE: To investigate the impact of one versus two distal locking bolts on the mechanical properties of tibial interlocking intramedullary nails. METHODS: Twenty 9-mm titanium alloy locking nails were divided into two equal groups in which the nails were fixed with only one and two distal locking bolts, respectively. Each group was further divided into two sub-groups for compression and torsion tests separately using a universal material-testing machine. RESULTS: In the compression tests, the average maximum strength of double bolts was greater than that of the single bolt (P<0.05), but the number of the bolts did not significantly affect the results of the torsion tests in terms of the either the maximum torsion moment or angle (P>0.05). CONCLUSION: One distal bolt is sufficient for fixing stable fractures and double bolts are recommended for management of serious fractures. The model we used is convenient and economic for examining the biomechanics of the tibial nails, especially for comparative purposes.

[Root canal treatment of mandibular first premolar with 4 root canals: a case report].

The mandibular first premolar can be considered one of the most challenging teeth to treat, due to the complexity of its root canal morphology and increased incidence of multiple canals. A case of endodontic treatment of a mandibular first premolar exhibiting a total of 4 distinct root canals and 4 apical foramina was described. Anatomic variation of root canal morphology should be considered in endodontic treatment to ensure a favorable healing outcome, and its identification could be enhanced by careful examination using a dental operating microscope. Obturation of root canals using a warm vertical compaction technique with a highly-radiopaque root canal sealer, such as AH Plus, after careful ultrasonic activated irrigation might allow the flow of sealer into the narrowed but unprepared part of the canal, thereby facilitating optimum chemo-mechanical debridement of the root canal system.

[Preliminary study on root canal morphology of maxillary second molars].

PURPOSE: To investigate the root canal morphology and anatomy of maxillary second molars using transparent tooth technique and cone-beam computed tomography (CBCT), and explore the consistency of 2 methods in identifying root canal configurations and morphology. METHODS: Fifty extracted maxillary second molars were scanned by CBCT and analyzed using assistant software. Root canal configurations of each root were identified based on Vertucci's classification and recorded. All transparent teeth samples were made with modified root canal staining technique, and the root canal configurations of each root were classified based on Vertucci's classification. The results were analyzed statistically with SPSS17.0 software package. RESULTS: According to transparent tooth technique, type I was the most common configuration in distobuccal root and palatal root. An additional configuration type 3-2-2 was found in the present study, which was not included in Vertucci's classification. The wide variety of canal systems was seen in the mesiobuccal root. Type I configuration was most prevalent(54.4%), followed by Type II, IV,V,VI. The prevalence of second canal in mesiobuccal root (MB2) was 41.3%. The results of canal morphology and configuration were consistent between transparent tooth technique and CBCT. CONCLUSIONS: Maxillary second molars have the most complex root and canal morphology, especially for the mesiobuccal root. For identifying root canal and root anatomy, CBCT can be used as an alternative to transparent tooth technique in clinical practice. The application of 3D reconstruction based on CBCT helps us to visualize the root canal anatomy.

[Application of problem-based learning in pre-job training of postgraduate students in department of endodontics].

PURPOSE: To apply problem-based learning (PBL) in pre-job training of postgraduate students in department of endodontics. METHODS: Thirty master degree postgraduate students of China Medical University were randomly divided into 2 groups, there were 15 students in each group. One group were taught with PBL method while the other group with lecture-based learning (LBL) method. The teaching effect was measured with examination and questionnaire survey. The data were analyzed by student's t-test using SPSS 11.5 software package. RESULTS: There was no significant difference in basic knowledge, medical records writing, oral examination between the two groups (P>0.05). There were significant differences in case analysis, dental operation, theory examination, practical examination and total scores between the two groups (P<0.05). The PBL method was welcomed by master degree postgraduate students. CONCLUSIONS: The abilities of postgraduate students can be developed by PBL method in different aspects. PBL achieves satisfactory teaching effect, and can be applied in pre-job training of postgraduate students.

[The application of cone-beam computed tomography in diagnosing the lesions of apical periodontitis of posterior teeth].

PURPOSE: To evaluate the effect of periapical radiography in diagnosing the lesions of the apical periodontitis (AP) of posterior teeth, with CBCT imaging as a standard. METHODS: One hundred and six posterior teeth in 80 patients were examined by periapical radiography and CBCT, which consisted of healthy teeth (58 teeth), chronic pulpitis (11 teeth), chronic apical periodontitis (34 teeth), remnant teeth with normal apical images after root canal therapy (3 teeth). All images were measured and evaluated by two experienced dentists by using periapical index (PAI) to ensure the classifications. The results were analyzed statistically with SPSS 13.0 software package for χ2 test. RESULTS: AP was identified in 39.6% and 59.4% of 106 cases by radiography and CBCT, the difference was significant (χ2=8.32, P<0.01). The use of conventional radiography for detection of AP should be done with care because of the great possibility of artifacts which might lead to misdiagnosis. Because of its accuracy, CBCT is more useful for clinic diagnosis and therapy. Furthermore, the images of CBCT could show destruction of cortical bone that couldn't detect by periapical radiography. CONCLUSIONS: CBCT is more accurate than periapical radiography for AP diagnosis. CBCT can reveal the details of the lesions and adjacent structures and provide correct clinical diagnosis and scientific treatment planning with accurate evidence.

[Effects of sulfur- and polymer-coated controlled release urea fertilizers on wheat yield and quality and fertilizer nitrogen use efficiency].

A field experiment was conducted to study the effects of sulfur- and polymer-coated controlled release urea fertilizers on wheat yield and its quality, plow layer soil inorganic nitrogen (N) contents, and fertilizer N use efficiency. Compared with traditional urea fertilizer, both sulfur- and polymer-coated controlled release urea fertilizers increased the grain yield by 10.4%-16.5%, and the grain protein and starch contents by 5.8%-18.9% and 0.3%-1.4%, respectively. The controlled release urea fertilizers could maintain the topsoil inorganic N contents to meet the N requirement for the wheat, especially during its late growth stage. In the meantime, the fertilizer N use efficiency was improved by 58.2%-101.2%. Polymer-coated urea produced better wheat yield and higher fertilizer N use efficiency, compared with sulfur-coated controlled release urea.

[Effect of Carisolv on endodontic microleakage].

PURPOSE: To evaluate the effect of Carisolv on endodontic microleakage by establishing a fluid transport model using sodium nitrite as tracer. METHODS: Seventy extracted teeth were randomly divided into 5 groups, all the root canals were prepared with different chemical reagents, including Carisolv,3% hydrogen peroxide+ 2%tosylchloramide sodium,2.5% sodium hypochlorite,5% sodium hypochlorite(negative control)and distilled water(positive control),post spaces were prepared after cold lateral condensation, the samples were put on the model, concentration of sodium nitrite which penetrated from the coronal to the apical end was measured by diazo reaction at 1,2,4,7,10,15,20,25,30,35,40,45,50,55 and 60 day. The data were analyzed by ANOVA using SPSS 11.5 software package. RESULTS: Sodium nitrite was not detected in negative control group from 1 day to 60 days. High concentration of sodium nitrite was detected in positive control group at first day, concentration of sodium nitrite was higher than that of other four groups from 1day to 60 days(P<0.01). Concentration of sodium nitrite in Carisolv group was significantly lower than that of 3%hydrogen peroxide+ 2% tosylchloramide sodium group(P<0.01), also lower than that of 2.5% sodium hypochlorite group(P<0.05),except at 25,30,35 and 40 days. CONCLUSIONS: Carisolv can remove the smear layer, decrease the endodontic microleakage, seal the root canal better. The fluid transport model using sodium nitrite as tracer can be used to evaluate the endodontic microleakage objectively,sensitively and exactly.

Extraction, partial characterization, and storage stability of ß-glucosidase from propolis.

Extraction and assay conditions for ß-glucosidase from propolis were optimized. Highest enzyme activity was obtained in a citric acid-disodium hydrogen phosphate buffer at pH 6.0 with 2.5% insoluble polyvinylpyrrolidone at incubation temperature of 57 °C. ß-Glucosidase activities were found in all freshly harvested propolis while ß-glucosidase activities were scarcely present in the randomly bought propolis. Propolis was stored at -20 °C and 4 °C for 3 mo with almost no loss of ß-glucosidase activity, but at room temperature the activity decreased exponentially with the increase of storage time. These results indicated that the activity of ß-glucosidase could be a candidate for propolis-freshness index. ß-Glucosidase from propolis was capable of hydrolyzing p-nitrophenyl-ß-D-glucoside and p-nitrophenyl-ß-D-galactoside, but lacked activity toward p-nitrophenyl-ß-D-glucuronide, p-nitrophenyl-ß-D-cellobioside, amygdalin, cellobiose, and gentiobiose. These results were consistent with the hypothesis that flavonoid glucosides were hydrolyzed by ß-glucosidase during propolis collection and processing and provided a possible explanation for why some flavonoid biosides (that is, rutin and isorhamnetin-3-O-rutinoside) exist in propolis. Practical Application: ß-Glucosidase activity was detected and partial characterization of the enzyme was determined in propolis. The enzyme activity decreased exponentially with the increase of storage time at room temperature, which suggested that the activity of ß-glucosidase could be regarded as a freshness index of propolis. The research will be useful for studying the chemical constituents of propolis.