Influence of sludge discharge on sludge settleability and membrane flux in a membrane bioreactor.

In this study, the correlations between sludge characteristics, amount of extracellular polymeric substances (EPS) and membrane fouling were investigated and analysed, using continuous sludge discharges from a membrane bioreactor (MBR). The results showed that continuous sludge discharges improved sludge settleability, but not always weakened membrane fouling. The changes in the EPS amount, caused by continuous sludge discharge from MBRs, could resolve this situation well. Soluble EPS concentration could be regulated, to some extent, by sludge discharges. But it was embarrassed to artificially adjust bound EPS amount because the MBRs included living microorganisms and their metabolites. After sludge had been discharged four times, the sludge volume index (SVI) was in the range of 50-60 mL x gSS(-1) with a VSS:SS ratio of about 0.8. Sludge settleability mainly depended on the bound EPS content. The bound EPS content and its components presented a closer relationship to sludge hydrophobicity than to the membrane flux. Soluble EPS dominated both the EPS content on the membrane surface and membrane fouling.

Inhibitory effects of resveratrol on orthodontic tooth movement and associated root resorption in rats.

OBJECTIVE: To investigate the effect of resveratrol (RSV) on orthodontic tooth movement (OTM) and orthodontic induced root resorption (OIRR) in rats. METHODS: Thirty-six male Wistar rats used in this study were randomly divided into three groups of 12 animals each. All test subjects underwent a 50 g orthodontic force each, generated from a nickel-titanium closed-coil spring. The control group were fed carboxymethylcellulose (CMC) while rats in other two groups were fed 5 mg/kg/d RSV or 10 mg/kg/d RSV (dissolved in CMC). After 14 days of OTM, all rats were sacrificed, after which each group was randomly divided into two subgroups (6 test subjects in each subgroup). One subgroup was used to measure the amount of OTM and assessed by hematoxylin and eosin (HE) staining, tartrate-resistant acid phosphatase (TRAP) staining, and immunohistochemistry staining of Receptor Activator of Nuclear Factor-κ B Ligand (RANKL), Osteoprotegerin (OPG), Runt-related transcription factor 2 (RUNX2), as well as Osteocalcin (OCN). The second subgroup was used to analyze OIRR via scanning electron microscopy. RESULTS: Compared with the control group, the RSV groups showed a significant decrease in the distance of OTM and the OIRR ratio (p＜0.05). The number of TRAP positive osteoclasts and the expression of RANKL in periodontal tissue of the RSV groups were significantly inhibited (p＜0.01) while the expression of OPG, RUNX2, and OCN were remarkably promoted (p＜0.05). The effect of 10 mg/kg/d RSV group was more obvious than that of 5 mg/kg/d RSV group (p＜0.05). CONCLUSIONS: RSV could reduce the extent of OTM and root resorption areas.

[The effect of rapamycin liposome gutta inhibiting rat corneal neovascularization].

OBJECTIVE: To explore the inhibiting effect of rapamycin (RAPA) on corneal neovascularization (CNV) of rats and the functional mechanism. METHODS: A design group was adopted. 102 Wistar rats were divided into four groups at random, including rapamycin liposome treated group (24 rats), the rapamycin solved in bean oil treated group (24 rats), blank liposome treated group (24 rats), blank treated group (24 rats) and normal control group (6 rats). All right eyes of 96 rats were induced by alkali cauterization. Rapamycin liposome were prepared by thin film hydration and the major factors were studied by the method of orthogonal design. After alkali burn, cauterized rats were observed by slitlamp biomicroscope every day. On the 1st, 4th, 7th, 14th days after operation, the expression of HIF-1alpha and VEGF were examined by immunohistochemical method and semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). The analysis of variance and q test groups for analysis were adopted to analyze the results. RESULTS: (1) The bodies of RAPA liposome were intact kinds of spheres, the average diameter was 145.2 nm, and the envelopment rate was 90.02%. (2) After the burn of 14 d, CNV area of B, C, D and E group were (28.289 +/- 0.703), (28.005 +/- 0.801), (20.002 +/- 1.005) and (22.300 +/- 0.853) mm(2) (F = 159.62, P < 0.05). The CNV of both the rapamycin liposome treated group and the rapamycin solved in bean oil group grew slowly and smaller than that of blank liposome treated group and blank treated group (q = 47.80, 46.20, 34.60, 32.90;P = 0.00). While the rapamycin liposome treated group changed more obviously than the rapamycin solved in bean oil group (q = 13.20, P = 0.00). After alkali burn, the expression of HIF-1alpha and VEGF increased dramatically, meanwhile the expression of HIF-1alpha and VEGF were significantly decreased by RAPA. CONCLUSIONS: Liposome body is an excellent medicine carrier for the RAPA. RAPA can obviously suppress the growth of CNV. The possibly mechanism is weakening VEGF expression by inhibiting the transcription factor HIF-1alpha.

[Effect of osthole on periodontal remodeling during orthodontic tooth movement in rats].

PURPOSE: To investigate the effect of osthole on periodontal remodeling during orthodontic tooth movement (OTM) in rats. METHODS: Seventy two 8-week-old male SD rats were randomly equally divided into 3 groups: two experimental groups of osthole with low (20 mg/kg) and high (40 mg/kg) concentration and the control group. Models of OTM were routinely established. Rats in the experimental groups were respectively given osthole by intragastric administration, while rats in the control group received the same volume of solvent. The rats were sacrificed on 7th, 14th, 21st and 28th day after orthodontic treatment, and the maxilla was harvested and the distance between the first and second molar was measured in each stage. Hematoxylin-eosin (H-E) staining, tartrate resistant acid phosphatase (TRACP) staining were performed. The results were analyzed with SPSS 20.0 software package for one-way analysis of variance. RESULTS: The mesio-moving distance of the three groups successively increased gradually. On the 7th day, there was no difference between the low concentration group and the control group (P>0.05); at other time point, the experimental groups exhibited significant differences from the control group(P<0.05), and the high concentration group had more obviously mesio-movement than the low concentration group(P<0.05). Histological observation showed that in the tension side, osteoblast appeared, but more apparent in the experimental groups than in the control group. In the pressure side, the number of osteoclast reached the peak at the 7th day, and much more osteoclasts were seen in the experimental groups than in the control group (P<0.05), in high concentration group than in low concentration group (P<0.05). The number of osteoclast decreased subsequently, but significant difference existed between the experimental groups and the control group (P<0.05) on the 14th day. At other time points, there was no significant difference among the three groups(P>0.05). CONCLUSIONS: Osthole could increase the number of osteoclast in periodontium and promote bone remodeling at the early stage of treatment, its effect is dose-dependence during OTM.

Preparation of roxithromycin-polymeric microspheres by the emulsion solvent diffusion method for taste masking.

Microspheres of roxithromycin with Eudragit S100 and silica were prepared by the emulsion solvent diffusion method to mask the bitter taste of the antibiotic. The effect of different polymers and drug-polymer ratios on the taste masking and the characteristics of the microspheres were investigated. It was found that Eudragit S100 was the best for masking the unpleasant taste of roxithromycin among the six kinds of polymers investigated. The results of DSC, X-ray diffraction and IR showed that there were several combinations of roxithromycin and Eudragit S100. The influence of other formulation factors, i.e. dichloromethane-acetone ratios and silica-polymer ratios on the properties of the microspheres were also examined. In conclusion, the results of the present study will be helpful for the preparation of oral forms of roxithromycin with an acceptable taste.

An artificial blood vessel implanted three-dimensional microsystem for modeling transvascular migration of tumor cells.

Reproducing a tumor microenvironment consisting of blood vessels and tumor cells for modeling tumor invasion in vitro is particularly challenging. Here, we report an artificial blood vessel implanted 3D microfluidic system for reproducing transvascular migration of tumor cells. The transparent, porous and elastic artificial blood vessels are obtained by constructing polysaccharide cellulose-based microtubes using a chitosan sacrificial template, and possess excellent cytocompatibility, permeability, and mechanical characteristics. The artificial blood vessels are then fully implanted into the collagen matrix to reconstruct the 3D microsystem for modeling transvascular migration of tumor cells. Well-defined simulated vascular lumens were obtained by proliferation of the human umbilical vein endothelial cells (HUVECs) lining the artificial blood vessels, which enables us to reproduce structures and functions of blood vessels and replicate various hemodynamic parameters. Based on this model, the adhesion and transvascular migration of tumor cells across the artificial blood vessel have been well reproduced.

Effects of traditional Chinese medicine on bone remodeling during orthodontic tooth movement.

ETHNOPHARMACOLOGICAL RELEVANCE: Dipsacus asper Wall (Dipsacaceae), Salvia miltiorrhiza (Salvia) and Drynaria fortunei (Drynaria) have been traditionally used in Chinese medicine as the main ingredient of many formulations for the treatment of cardiovascular and inflammatory diseases. AIM OF THE STUDY: This study was aimed to evaluate the effect of the traditional Chinese medicine (TCM) Dipsacaceae, Salvia and Drynaria on bone remodeling during orthodontic tooth movement (OTM). SETTING: This study was conducted in School of Stomatology, Shandong University between 2009 and 2010 [Jinan, Shandong, China]. MATERIALS AND METHODS: Ninety-six eight-week-old female SPF Wistar rats 180-200 g were selected and randomly divided into four groups of 24: Dipsacaceae group, Salvia group, Drynaria group and control group. Animal models for orthodontic tooth movement were then established which consisted of a closed coil spring ligated to the upper first molar and incisors, exerting a force of 40 g during the experimental period. Rats in the TCM groups were given Dipsacaceae, Salvia and Drynaria decoction respectively by intragastric administration 6 g/kg/day and the control group were given normal saline 3 ml. The rats were sacrificed in batch on the 7th, 14th, 21st and 28th days after orthodontic treatment. Slices from periodontium of the upper first molar were observed under optical microscope. Neovascularization, new bone formation and osteoclast number were observed. RESULTS: The upper first molars were drawn mesial by the force. Telangiectasia and new bone formation in periodontal tissue were significantly in the TCM groups compared with the control group. Application of orthodontic forces in the experimental teeth showed a significant increase (P<0.05) of osteoclast number in the TCM group when compared with the control group. In addition, the number of osteoclast had no significant differences among the TCM groups (P>0.05). Osteoclast number in the TCM group and the control group were 10.12±0.058, 10.13±0.022, 10.09±0.047 and 9.55±0.045, respectively. CONCLUSIONS: These findings suggest that the TCM decoction are beneficial to the alveolar bone remodeling by promoting osteoclast differentiation during OTM.

[Three dimensional changes of lower teeth with NiTi round or square rocking chair archwire].

PURPOSE: To observe the three-dimensional change of lower arch when NiTi round and square rocking chair archwire was used to open overbite in patients of Angle Class I or Class II with deep overbite,in order to providing experimental basis for clinicians. METHODS: Forty patients were chosen according to the inclusion standard. The patients were divided into four groups according to different archwire and with or without use of lace back and cinch back. The patients were taken plaster model before and after the overbite opened by using typical swinging chair labial arch, Laser scan and imageware software were used to make digital model and measure the three dimensional changes of the lower teeth,All data were analyzed with SPSS 12.0 software package. RESULTS: When Rocking chair archwire was used to open overbite, it made the teeth changed in three dimensions, but the arch shape changed unconspicuously. The width between molars increased while the width between the canines and premolars had little change. The arch length had a tendency to increase and the incisors were intruded and had the tendency of labioclination, the incisor labioclination was more significant with lace back and cinch back. The canines showed the tendency of apical clination and there were obvious changes with the lace back and cinch back,the intruding-extruding change was not obvious. The second premolars were elevated, and the mesio-buccal cusp of the first molar did not move while the apo-buccal cusp was intruded.The first molars have the tendency of distal movement and lingual movement when using NiTi square wire. CONCLUSIONS: In the process of opening overbite using rocking chair labial arch, there are different three-dimensional changes of the mandibular arch with NiTi round or square archwire, with or without lace back and cinch back.

[The establishment of three dimensional finite element model of a maxillary impacted canine and its support tissues].

PURPOSE: To establish a three dimensional finite element model of a maxillary impacted canine and its support tissues by means of finite element method (FEM) and spiral CT which can offer digital model for orthodontic traction. METHODS: A patient with a completely bony impacted maxillary canine was chosen. The CAD model of the canine and its surrounding tissues was established using spiral CT equipment, Mimics and Unigraphic. The CAD model was changed to FEM models by MSC. Mentat which could cut nets in CAD models. RESULTS: With the use of spiral CT,Mimics,UG and MSC, FEM model of the maxillary impacted canine and its support tissues and the whole maxilla was constructed and the model was of high geometrical similarity. CONCLUSION: The FEM model of maxillary impacted canine established by spiral CT,Mimics,UG and MSC has high accuracy, integrated constitution and optimized mesh which can be taken into account in the course of the treatment planning prior to starting therapy.