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The continuous predator-prey model is one of the main models studied in recent years. The dynamical properties of these models are so complex that it is an urgent topic to be studied. In this paper, we transformed a continuous predator-prey model with modified Leslie-Gower and Hollingtype III schemes into a discrete mode by using Euler approximation method. The existence and stability of fixed points for this discrete model were investigated. Flip bifurcation analyses of this discrete model was carried out and corresponding bifurcation conditions were obtained. Provided with these bifurcation conditions, an example was given to carry out numerical simulations, which shows that the discrete model undergoes flip bifurcation around the stable fixed point. In addition, compared with previous studies on the continuous predator-prey model, our discrete model shows more irregular and complex dynamic characteristics. The present research can be regarded as the continuation and development of the former studies.

Objective: To determine the effect of implant position on clinical crown length and papilla fills in implant-supported maxillary central incisors., Methods: One implant replacing the 11th or 21st tooth was given to 158 patients who lost a maxillary central incisor after trauma. The contra-lateral central incisors were used as controls. The three-dimensional positional parameters were estimated using standardized photographs of the cast models, clinical photographs and peri-apical radiographs. Paired t tests were performed to examine the differences between the implants and the control teeth in clinical crown length, papilla fills, proximal bone crest levels, and the horizontal implant-teeth distance at the mesial and distal implant. Pearson correlations were used to identify the implant positional parameters associated with crown length and papilla fills., Results: The implant-supported crowns were statistically longer than the controls [(10.9±1.1) mm vs. (10.4±0.8) mm, P <0.05]. Greater papilla fills were found in the mesial implants and distal contra-lateral teeth compared with the distal implants ( P <0.000 1). The implants had higher levels of mesial proximal bone crest than the distal [(2.2±1.4) mm vs. (1.2±1.5) mm, P <0.05]. The oro-facial position of the implants was associated with the crown length ( R =0.602, P =0.001). But the crown length was not correlated with the sagital angulation of the implants or the vertical distance from the implant fixture to the soft tissue margin. The proximal bone crest level was correlated with the papilla fill height ( R =0.400, P =0.001)., Conclusion: An implant positioned buccally results in longer crown length. Minor buccal angulations of the implant do not necessarily result in increased crown length. Appropriate position and input depth may help avoid bone absorption and papilla shrinkage., (Copyright© by Editorial Board of Journal of Sichuan University (Medical Science Edition).)

Objective: To observe the cytopathogenic inhibitory effect of resveratrol on vary respiroviruses and explore the mechanism of resveratrol against viruses., Methods: MDCK, A549, HEp-2 cell and MRC-5 were infected with Influenza virus type A FM1 strain, rhinovirus type R14, RS virus, AD virus type 7 separately, and the antiviral activity of resveratrol were observed., Results: Resveratrol significantly inhibited cytopathogenic effect of AD virus type 7 at the concentration 120 microg/ml. No significant cytopathogenic effect of Resveratrol inhibiting Influenza virus type A FM1 strain, Rhinovirus type R14, RS virus on separate cells was observed., Conclusion: It is concluded that resveratrol is effective on inhibiting AD virus type 7 in vitro, however, its mechanism is needed for further study.

Four new hasubanane-type alkaloids, periglaucines A-D (1-4), and three known alkaloids, norruffscine (5), (-)-8-oxotetrahydropalmatine (6), and (-)-8-oxocanadine (7), were isolated from the aerial parts of Pericampylus glaucus. Their structures were elucidated on the basis of extensive NMR and EIMS data, and that of periglaucine A (1) was confirmed by single-crystal X-ray diffraction. Alkaloids 1-4 inhibited hepatitis B virus (HBV) surface antigen (HBsAg) secretion in Hep G2.2.15 cells. (-)-8-Oxotetrahydropalmatine (6) possessed a high selectivity index (SI = 22.4) for HBsAg secretion of the Hep G2.2.15 cell line with an IC(50) value of 0.14 mM. Norruffscine (5) and (-)-8-oxotetrahydropalmatine (6) exhibited inhibitory activity against human immunodeficiency virus (HIV-1) with EC(50) values of 10.9 and 14.1 microM in C8166 cells (SI = 45.7 and 18.8), respectively.

Objective: To prepare the Zedoary Turmeric Oil spray and investigate its anti-virus effects., Methods: According to the Zedoray Turmeric Oil and Glucose Injection, the new dosage of Zedoray Turmeric Oil spray was studied. Antiviral effects of the Zedoary Turmeric Oil spray in the respiratory tract were studied both in vivo and in vitro., Results: The quality of the Zedoary Turmeric Oil spray was controlled. The influenza virus, parainfluenza Virus I, III, RS virus and AD virus 3,7 could be inhibited slightly, but the parainfluenza Virus II could be obviously inhibited by the Zedoary Turmeric Oil spray., Conclusion: The Zedoary Turmeric Oil spray's formula is simple, useful and safe.

Aim: To observe the Lamivudine resistance character of a DHBV strain in vitro and in vivo, and to analyze if the Lamivudine resistance character is caused by gene mutation or by abnormity of the Lamivudine metabolism., Methods: Congenitally DHBV-negative Guangdong brown ducks and duck embryo liver cells were respectively taken as animal and cell model. The Lamivudine-susceptive DHBV and Lamivudine-resistant DHBV (LRDHBV) were infected and Lamivudine was administrated according to the divided groups. The changes of DHBV quantity in the animal and cell model were tested. Three Lamivudine-resistant and two Lamivudine-susceptive DHBV complete genomes were successfully amplified, sequenced and then submitted to GenBank. All the DHBV complete sequences in the GenBank at present were taken to align with the three LRDHBV to analyze the mutational points related to the Lamivudine-resistant mutation., Results: Both the animal and cell model showed that the large and the small dosage Lamivudine have no significant inhibitory effect on the LRDHBV. Five sequences of DHBV complete genomes were successfully cloned. The GenBank accession numbers of the three sequences of LRDHBV are AY521226, AY521227, and AY433937. The two strains of Lamivudine-susceptive DHBV are AY392760 and AY536371. The correlated mutational points are KorR86Q and AorE591T in the P protein., Conclusion: The Lamivudine resistance character of this DHBV strain is caused by genome mutation; the related mutational points are KorR86Q and AorE591T and have no relations with the YMDD motif mutation.

Aim: To study the anti-HBV effect of liposome-encapsulated matrine (Lip-M) in vitro and in vivo., Methods: 2.2.15 cell line was cultured in vitro to observe the effect of Lip-M and matrine on the secretion of HBsAg and HBeAg. The toxicity of Lip-M and matrine to 2.2.15 cell line was also studied by MTT method. In in vivo study, drug treatment experiment was carried out on the 13th day after ducks were infected with duck hepatitis B virus (DHBV). The ducks were randomly divided into 4 groups with 5-6 ducks in each group. Lip-M and matrine were given to DHBV-infected ducks respectively by gastric perfusion. Four groups were observed: group of Lip-M (20 mg/kg), group of Lip-M (10 mg/kg), group of matrine (20 mg/kg) and group of blank model. The drug was given once daily for 20 d continuously, and normal saline was used as control. The blood was drawn from the posterior tibial vein of all ducks before treatment (T(0)), after the medication for 5 (T5), 10 (T10), 15 (T15), 20 (T20) d and withdrawl of the drug for 3 d (P3). The serum samples were separated and stored at -70 degrees, DHBV-DNA was detected by the dot-blot hybridization., Results: After addition of Lip-M and matrine to 2.2.15 cell line for eleven d, the median toxic concentration (TC50) of Lip-M and matrine was 7.29 mg/mL and 1.33 mg/mL respectively. The median concentration (IC50) of Lip-M to inhibit HBsAg and HBeAg expression was 0.078 mg/mL and 3.35 mg/mL respectively. The treatment index (TI) value of Lip-M for HBsAg and HBeAg was 93.46 and 2.17 respectively, better than that of matrine. The DHBV-infected duck model treatment test showed that the duck serum DHBV-DNA levels were markedly reduced in the group of Lip-M (20 mg/kg) after treated by gastric perfusion for 10, 15 and 20 d (0.43+/-0.22 vs 0.95+/-0.18, t = 4.70, P = 0.001<0.01.0.40+/-0.12 vs 0.95+/-0.18, t = 6.34, P = 0.000<0.01. 0.22+/-0.10 vs 0.95+/-0.18, t = 8.30, P = 0.000<0.01), compared to the group of matrine (20 mg/kg) (0.43+/-0.22 vs 0.79+/-0.19, t = 3.17, P = 0.01<0.05. 0.40+/-0.12 vs 0.73+/-0.24, t = 3.21, P = 0.009<0.05. 0.22+/-0.10 vs 0.55+/-0.32, t = 2.27, P = 0.046<0.05.), and the control(0.43+/-0.22 vs 0.98+/-0.29, t = 3.68, P = 0.005<0.01. 0.40+/-0.12 vs 0.97+/-0.30, t = 4.26, P = 0.002<0.01. 0.22+/-0.10 vs 0.95+/-0.27, t = 5.76, P = 0.000<0.01). After the treatment for 20 d and withdrawl of the drug for 3 d, duck serum DHBV-DNA level in the group of Lip-M (10 mg/kg) markedly reduced (0.56+/-0.26 vs 0.95+/-0.38, t = 5.26, P = 0.003<0.05. 0.55+/-0.25 vs 0.95+/-0.38, t = 5.52, P = 0.003<0.05), and the difference was significant as compared with the control (0.56+/-0.26 vs 0.95+/-0.27, t = 2.37, P = 0.042<0.05. 0.55+/-0.25 vs 0.89+/-0.18, t = 2.55, P = 0.031<0.05), but not significant as compared with the group of matrine (20 mg/kg). After withdrawl of the drug for 3 d, the levels of DHBV-DNA did not relapse in both groups of Lip-M., Conclusion: Lip-M can evidently inhibit the replication of hepatitis B virus in vitro and in vivo; its anti-HBV effect is better than that of matrine.

Objective: To explore the therapeutic effect of combination of Zhuanyindan (ZYD, a self-made Chinese herbal preparation) and hormone in treating male infertility with positive antisperm antibody and its influence on nitric oxide (NO) level., Methods: Eighty-two patients were randomly divided (according to the digital list) into the WM group (n = 20, treated with prednisone), the TCM group (n = 28, treated with ZYD) and the ICWM group (n = 34, treated with prednisone plus ZYD). The clinical effect, negative converting rate of antisperm antibody, changes of NO level in semen and various parameters of sperm motion before and after treatment were observed., Results: The total effective rate in the ICWM group was 88.2%, that in the TCM group 75.0% and in the WM group 65.0%. Significant difference was seen in the ICWM and TCM group before and after treatment in NO level, sperm motion parameters, including linear motion speed, linearity, propulsion, whip frequency, sperm vitality and mean moving angle, and quality of semen (P < 0.05 or P < 0.01). In the WM group, significant difference in comparison before and after treatment was seen in NO level, propulsion, whip frequency, mean moving angle and quality of semen, including vitality and survival rate (P < 0.01)., Conclusion: Combination of Chinese herbs and hormone could lower the NO level in semen and improve the quality of sperm.