Soft-tissue deformation is one of the important research directions in virtual surgery. Mass-spring model and finite-element model are the two most important modeling technology of the soft tissue modeling. It is very important for the current soft-tissue deformation modelling to analysize, to summarize the main idea, the influence factors and the modeling route of the two kinds of modeling methods and then to give comprehensive review.
Computer Simulation ; Humans ; Models, Biological ; Surgery, Computer-Assisted ; methods ; User-Computer Interface

A series of cycloberberine derivatives were designed, synthesized and evaluated for their anti-cancer activities in vitro. Among these analogs, compounds 6c, 6e and 6g showed strong inhibition on human HepG2 cells. They afforded a potent effect against DOX-resistant MCF-7 breast cells as well. The primary mechanism showed that cell cycle was blocked at G2/M phase of HepG2 cells treated with 6g using flow cytometry assay. It significantly inhibited the activity of DNA Top I at the concentration of 0.1 mg mL-1. Our results provided a basis for the development of this kind of compounds as novel anti-cancer agents.

A series of novel N-(2-arylethyl) isoquinoline derivatives were designed, synthesized and evaluated for their anti-cancer activities. Among these analogs, compound 9a exhibited the potential anti-cancer activities on HepG2 and HCT116 cells with IC50 values of 2.52 and 1.99 microg x mL(-1), respectively. Cell cycle was blocked at S phase of HepG2 cells treated with 9a by flow cytometry detection. Our results provided a basis for the development of a new series of anti-cancer candidates.

Objective : To evaluate the effect of 2. 5% NaClO solution as irrigating agent on the healing of dental pulp after preservation treatment in rats with inflammatory pulp. Methods : 48 maxillary molars of 24 8 ⁃week⁃old male SD rats were selected and pulpitis models were established by pulp cavity exposure for 24 hours. Then part of the crown pulp was removed and divided into two groups according to different irrigation methods : 2. 5% NaClO flushing group (NaClO) and saline flushing group (NS) . The pulp was covered with iRoot BP Plus and the cavity was sealed with glass ionomer. Four animals in the two groups were killed on the 1st , 7th and 28th day after opera⁃ tion , respectively. And the inflammatory reaction , tissue destruction and hard tissue formation of residual dental pulp tissue were observed and evaluated by histopathology. Results : The pulp inflammatory reaction , tissue de⁃ struction and restorative dentin formation in 2. 5% NaClO irrigation group and saline irrigation group were similar on the 1st , 7th and 28th day after operation , there was no significant difference between the two groups. Conclusion 2. 5% NaClO used as a hemostatic before iRoot BP Plus pulp capping after partial pulpotomy has similar effect with normal saline on the inflammatory pulp model of rats , and does not affect the healing of pulp inflammation.

Taking 12-N-p-chlorobenzyl sophoridinol 2 as a lead, a series of novel sophoridinic derivatives with various 3'-substituents at the 11-side chain were synthesized and evaluated for their anticancer activity from sophoridine (1), a natural antitumor medicine. Among them, the sophoridinic ketones 5a-b, alkenes 7a-b and sophoridinic amines 14a-b displayed reasonable antiproliferative activity with IC50 values ranging from 3.8 to 5.4 μmol/L. Especially, compounds 5a and 7b exhibited an equipotency in both adriamycin (AMD)-susceptible and resistant MCF-7 breast carcinoma cells, indicating a different mechanism from AMD. The primary mechanism of action of 5a was to arrest the cell cycle at the G0/G1 phase, consistent with that of parent compound 1. Thus, we consider 12-chlorobenzyl sophoridinic derivatives with a tricyclic scaffold to be a new class of promising antitumor agents with an advantage of inhibiting drug-resistant cancer cells.

Objective: This ex vivo study evaluated the effect of ultrasound and Er:YAG laser irrigation activation techniques on the penetration of sodium hypochlorite solution into infected human root canal dentin, providing a reference for clinical infection control of infected root canals. Methods : Thirty-six cases of infected root canals were collected and randomly divided into three groups according to the irrigation technique: 12 cases in the conventional syringe irrigation (CSI) group, 12 cases in the passive ultrasonic irrigation (PUI) group, 12 cases in the Er:YAG laser and photon-induced photoacoustic streaming (PIPS) group and 36 cases of clean root canals (12 cases in the CSI group, 12 cases in the PUI group, 12 cases in the PIPS group). All of the selected root canals were straight root canals of posterior teeth. After standardizing the root length, all canals were subjected to instrumentation and dynamic irrigation. 2% methylene blue solution was used to visualize the penetration of the irrigant. EXAKT cutting and grinding equipment was used to take transverse sections of 100-150 μm at the coronal, middle and apical thirds of the root canals. The data (maximum penetration depth, average penetration depth, and penetration percentage) were observed under a light microscope to evaluate the effect of dye penetration. Results : With the three irrigation techniques, the maximum penetration depth, average penetration depth and penetration percentage of the infected root canals were significantly lower than those of clean root canals in the full length of the root canal (P<0.05). The penetration percentage, average penetration depth and maximum penetration depth of the PIPS group were significantly higher than those of the CSI group in the coronal, middle and apical thirds of the infected root canal, respectively (P<0.05). There was no significant difference in the maximum penetration depth, average penetration depth or penetration percentage between the PUI and CSI groups (P>0.05). There was also no significant difference in the maximum penetration depth, average penetration depth or penetration percentage between the PIPS and PUI groups (P>0.05). Conclusion The dentine permeability of infected root canals was weaker than that of clean root canals. Er:YAG laser-assisted irrigation activation technology could significantly improve the penetration of sodium hypochlorite solution into infected dentin, but passive ultrasonic irrigation did not significantly improve the penetration.

Objective : To evaluate the anti⁃inflammatory effect of tissue inhibitor of metalloprotease (TIMP1) on a rat model of irreversible pulpitis. Methods : An irreversible pulpitis model was established by pulp exposure on maxillary first molars of 8 ⁃10 weeks old male rats , and pulpotomy was performed at 24 h , 36 h and 48 h after pulp exposure , with TIMP⁃1 covering the pulp section (TIMP⁃1 group) and saline as control (NS group) . Coronal obturation were performed with glass⁃ionomer cement. Histological and immunohistochemical analysis were performed at 24 and 48 h after administration. Results : Quantitative histopathological analysis of HE⁃stained sections showed that the inflammation score (inflammatory cellular response of the root pulp , morphological changes in root pulp tissue and extent of root pulp necrosis) of the pulp were higher in the TIMP⁃1 group than those in the NS group (P < 0. 001 or P < 0. 01) . Immunofluorescence staining (CD68⁃labeled) sections showed that the intensity of CD68 immunofluorescence was higher in the TIMP⁃1 group than that in the NS group (P < 0. 001) . Conclusion TIMP⁃1 had no anti⁃inflammatory effect in a rat model of irreducible pulpitis and increased the degree of inflammation in the root pulp.