[Adenosine triphosphate induced odontoblastic differentiation of human dental pulp cells in vitro and in vivo].

Objective: To choose a suitable efficient concentration of adenosine triphosphate (ATP) which can induce human dental pulp cells (HDPC) differentiate into odontoblast successfully, and explore the role of this concentration of ATP in dentin regeneration in vivo. Methods: HDPC were treated with different concentrations (0, 10, 400, 600, 800 µmol/L) of ATP. Then cell counting kit-8 (CCK-8), quantitative real-time PCR, and Western blotting were used to detect the cell proliferation and the expressions of odontoblastic differentiation related markers, dentin matrix protein 1 (DMP1) and dentin sialophosphoprotein (DSPP). Alizarin red S staining experiment was used to analyze the effect of ATP on the mineralization ability of HDPC. By the above experiments, the suitable effective concentration of ATP was chosen to pretreat the HDPC for 7 days, then cells were seeded on gelfoam, inserted into the root canal fragment, and subsequently transplanted into the subcutaneous space on the back of immunodeficient mice, after three months, the samples were stained with HE for histological analysis. Results: The CCK-8 results in 5 d showed that 10 µmol/L ATP obviously promoted the proliferation of HDPC, while the 600 and 800 µmol/L ATP apparently inhibited the HDPC proliferation, however, the proliferation in 800 µmol/L ATP group was lower than that of 600 µmol/L ATP group (P<0.05). qPCR and Western blotting results showed that the 600 and 800 µmol/L ATP significantly up-regulated the DMP1 and DSPP expressions (P<0.05), furthermore, there was no significant difference in the two groups, but no changes were found in other groups (P>0.05). After 21 days of culturing, there were obvious mineralization nodules in 600 and 800 µmol/L ATP groups, but no mineralization nodules in other groups. Quantitative analysis of the staining results showed the A value in 0, 10, 400, 600, and 800 µmol/L ATP groups were respectively 1.05±0.15, 1.11±0.23, 1.15±0.17, 3.65±0.30, and 3.40±0.43, and the A value in 600 and 800 µmol/L ATP groups were higher than those of other groups; however, there was no difference in 600 and 800 µmol/L ATP groups. The histological analysis showed that 600 µmol/L ATP could induce the HDPC differentiate into dentin-like structure in the root canal fragment. Conclusions: Therefore, the suitable effective concentration of ATP is 600 µmol/L, which could induce HDPC differentiate into odontoblast-like cells, and form the dentin-like structure in vivo.

Separation of oil/water emulsion using nano-particle (TiO(2)/Al(2)O(3)) modified PVDF ultrafiltration membranes and evaluation of fouling mechanism.

In the present study, nano-sized TiO(2)/Al(2)O(3) modified polyvinylidene fluoride (PVDF) membranes (MM) were fabricated and then utilized for oil/water emulsion separation. The results showed that, compared with PVDF membrane (OM), the contact angle of MM decreased and hydrophilicity increased. The ultrafiltration (UF) of oil in water emulsions with transmembrane pressure (TMP) increasing results in a sharp fall in relative flux with time. The cake filtration models did not always predict the performance over the complete range of filtration times very well. In the initial 30 min, all the four cake models can simulate this UF process to a certain extent, and the suitability was: cake filtration > intermediate pore blocking > standard pore blocking > complete pore blocking models. However, they were no longer adapted well with UF time extent to 60 min, but only cake filtration (R(2) = 0.9535) maintained a high adaptability. Surface and cross-sectional morphology of the membrane was investigated by SEM to make an advanced certificate of this UF mechanism.

Optimization of complex conditions by response surface methodology for APAM-oil/water emulsion removal from aqua solutions using nano-sized TiO2/Al2O3 PVDF ultrafiltration membrane.

This paper studies the cumulative effect of various parameters, namely anionic polyacrylamide (APAM) concentration, oil concentration, pH, trans-membrane pressure (TMP), and total dissolved solid (TDS), and obtains optimal parameters for the minimum relative flux (J/J(0)) declining in aqueous solutions with response surface methodology (RSM). In order to analyze the mutual interaction and optimal values of parameters affecting ultrafiltration, a central composite rotatable design (CCRD), one method of RSM, was employed. The analysis of variance (ANOVA) of the cubic polynomial model demonstrated that this model was highly significant and reliable. The results show that the effect of APAM and oil on J/J(0) has an inverse trend with pH value increasing. Moreover, the mutual interaction of initial APAM (oil) concentration (C(APAM(oil))) and pH (TMP) were negligible, while the mutual interaction of C(APAM) and C(oil) has an obvious effect, i.e. the effect of initial feed C(APAM) became more important at higher values of initial feed C(oil), and the J/J(0) was only about 4%. The favorable operate conditions in this ultrafiltration process were at low C(APAM), C(oil), pH, and TMP, which agreed with the conclusions of many authors, while considering water production, C(APAM) and C(oil) < 50 mg/L, pH < 4, and TMP < 0.075 MPa could be accepted.

Isotherm and kinetic behavior of adsorption of anion polyacrylamide (APAM) from aqueous solution using two kinds of PVDF UF membranes.

To determine the isotherm parameters and kinetic parameters of adsorption of anion polyacrylamide (APAM) from aqueous solution on PVDF ultrafiltration membrane (PM) and modified PVDF ultrafiltration membrane (MPM) is important in understanding the adsorption mechanism of ultrafiltration processes. Effect of variables including adsorption time, initial solution concentration, and temperature were investigated. The Redlich-Peterson equation of the five different isotherm models we chose was the most fitted model, and the R(2) was 0.9487, 0.9765 for PM and MPM, respectively; while, the pseudo-first-order model was the best choice among all the four kinetic models to describe the adsorption behavior of APAM onto membranes, suggesting that the adsorption mechanism was a chemical and physical combined adsorption on heterogeneous surface. The thermodynamic parameters were also calculated from the temperature dependence (Δ(r)G(m)(θ), Δ(r)H(m)(θ), Δ(r)S(m)(θ)), which showed that the process of adsorption is not spontaneous but endothermic process and high temperature favors the adsorption.