Pathway toward large two-dimensional hexagonally patterned colloidal nanosheets in solution.

We report the solution self-assembly of an ABC block terpolymer consisting of a polystyrene-block-poly(ethylene oxide) (PS-b-PEO) diblock copolymer tail tethered to a fluorinated polyhedral oligomeric silsesquioxane (FPOSS) cage in 1,4-dioxane/water. With increasing water content, abundant unconventional morphologies, including circular cylinders, two-dimensional hexagonally patterned colloidal nanosheets, and laterally patterned vesicles, are sequentially observed. The formation of toroids is dominated by two competing free energies: the end-cap energy of cylinders and the bending energy to form the circular structures. Incorporating the superhydrophobic FPOSS cages enhances the end-cap energy and promotes toroid formation. Lateral aggregation and fusion of the cylinders results in primitive nanosheets that are stabilized by the thicker rims to partially release the rim-cap energy. Rearrangement of the parallel-aligned FPOSS cylindrical cores generates hexagonally patterned nanosheets. Further increasing the water content induces the formation of vesicles with nanopatterned walls.

Preparation of novel poly(hydroxyethyl methacrylate-co-glycidyl methacrylate)-grafted core-shell magnetic chitosan microspheres and immobilization of lactase.

Poly(hydroxyethyl methacrylate-co-glycidyl methacrylate)-grafted magnetic chitosan microspheres (HG-MCM) were prepared using reversed-phase suspension polymerization method. The HG-MCM presented a core-shell structure and regular spherical shape with poly(hydroxyethyl methacrylate-co-glycidyl methacrylate) grafted onto the chitosan layer coating the Fe3O4 cores. The average diameter of the magnetic microspheres was 10.67 µm, within a narrow size distribution of 6.6-17.4 µm. The saturation magnetization and retentivity of the magnetic microspheres were 7.0033 emu/g and 0.6273 emu/g, respectively. The application of HG-MCM in immobilization of lactase showed that the immobilized enzyme presented higher storage, pH and thermal stability compared to the free enzyme. This indicates that HG-MCM have potential applications in bio-macromolecule immobilization.

Orchestrating Chemical and Physical Cross-Linking in Protein Hydrogels to Regulate Embryonic Stem Cell Growth.

Protein hydrogels are ideal candidates for next-generation biomaterials due to their genetically programmable properties. Herein, we report an entirely protein-based hydrogel as an artificial extracellular matrix (ECM) for regulating the embryonic stem cell growth. A synergy between chemical and physical cross-linking was achieved in one step by SpyTag/SpyCatcher reaction and P zipper association at 37 °C. The hydrogels' stress relaxation behaviors can be tuned across a broad spectrum by single-point mutation on a P zipper. It has been found that faster relaxation can promote the growth of HeLa tumor spheroids and embryonic stem cells, and mechanical regulation of embryonic stem cells occurs via retention of the cells at the G1 phase. The results highlight the promise of genetically encoded protein materials as a platform of artificial ECM for understanding and controlling the complex cell-matrix interactions in a 3D cell culture.

Nanowire-haired inorganic membranes with superhydrophilicity and underwater ultralow adhesive superoleophobicity for high-efficiency oil/water separation.

A novel all-inorganic Cu(OH)2 nanowire-haired membrane with superhydrophilicity and underwater ultralow adhesive superoleophobicity is fabricated by a facile surface oxidation of copper mesh that allows effective separation of both immiscible oil/water mixtures and oil-in-water emulsions solely driven by gravity, with extremely high separation efficiency. The all-inorganic membrane exhibits superior solvent and alkaline resistance and antifouling property compared to organic-based membranes.

[Vertical distribution characteristics of nutrients and heavy metals in sediments of Lake Hongze].

In order to understand the vertical distribution characteristics of nutrients and heavy metals in sediments of Lake Hongze, three core sediment samples at 3 sites (one near the Huaihe River inlet of Lake Hongze, one at the western part of the lake and one at the lake center) were collected in June of 2008. By measurement of total nitrogen (TN), total phosphorus (TP) and heavy metals (Cu, Zn, Pb, Cd, Fe, Al, Cr, Hg, Mn, As) and by analyzing of their vertical characteristics, investigation revealed the nutrient evolution processes and pollution history. Sediment near Huaihe river mouth was more polluted by the Huaihe River watershed. The nutrients TN, TP and organic matter (OM) concentrations in this core sample were 390.8-643.7, 428.6-538.6, 5 194.3-9 164.9 mg x kg(-1) respectively. Zn, Cd, Al, Fe and Mn in the sediment in this area were affected by human activities less than other heavy metals. Western Lake sediment was affected by the Huaihe River, inlet river and human activities in cities along western lake shoreline. TN, TP and OM concentrations in this core sample were 633.4-2 677.3, 480.0-1115.9, 7 140.8-47 849.7 mg x kg(-1) respectively. The pollution extents of TN, OM and heavy metals in sediment were exacerbated since the late of 1970s, but the situation was improved since the 1990s. As and Cr in the sediments were influenced by human activities more than other heavy metals. Main pollution source in sediment at the lake center were detritus from the lake watershed. TN, TP and OM concentrations in this core sample were 904.7-1 585.4, 526.3-750.1, 10 635.6-19 020.6 mg x kg(-1) respectively. The correlations among nutrients and heavy metals in sediment are significant, and their vertical distribution patterns were similar. The concentrations of nutrients and heavy metals increased from bottom to surface. Nutrients and heavy metal pollution in sediment had the same vertical distribution characteristics which coincided with the lake watershed economic development stage. The sediment in Lake Hongze can be described by the Turbidity Flood Model.

[Maxillary sinus floor augmentation using gene-enhanced tissue engineered bone].

OBJECTIVE: To evaluate the effect of maxillary sinus elevation with gene-enhanced tissue engineering bone in dogs. METHODS: bone marrow stromal cells (BMSC) derived from dog marrow were cultured, and transduced with the adenovirus carrying bone morphogenetic protein-2 (BMP-2) gene (AdBMP-2), the adenovirus carrying green fluorescent protein (GFP) gene (AdGFP) in vitro. The bone formation ability of gene modified BMSC with scaffold was examined in nude mice and in elevated maxillary sinus of dog. Student's t-test was used for statistical analysis with SPSS 11.0 software package. RESULTS: Gene transfection efficiency reached up to (83.95 ± 2.43)% as demonstrated by GFP expression. Ectopic bone formation was detected in nude mice. As for maxillary sinus floor elevation in a dog model, new bone formation area in the AdBMP-2 gene transduced BMSC with Bio-Oss group was significantly higher than in BMSC with Bio-Oss group at 120 d (P < 0.05). CONCLUSIONS: AdBMP-2 gene transduced BMSC can stimulate ectopic bone formation in nude mice, and promote bone formation and maturation in the dog maxillary sinus.

[Distribution and potential ecological risk assessment of heavy metals in surface sediments of Hongze Lake].

In order to investigated horizontal distribution patterns of heavy metals in surface sediments of Hongze Lake, heavy metal contents in every samples were measured by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) and Atomic Fluorescence spectrometry (AFS) and the potential ecological risks of each heavy metals were analyzed. The average contents of heavy metals Cu, Zn, Pb, Cd, Cr, Hg, As, Fe, Al and Mn are 34.99 mg/kg, 72.44 mg/kg, 18.82 mg/kg, 3.24 mg/kg, 57.59 mg/kg, 0.07 mg/kg, 23.67 mg/kg, 29.63 mg/g, 37.19 mg/g and 0.69 mg/g, respectively. Horizontal distribution patterns of every heavy metals (Cu, Zn, Pb, Cd, Fe, Al, Cr, Hg, Mn and As) in surface sediments were very similar. By impact of hydodynamical and topographical condition, the contents of heavy metals were significantly lower in the inflow river mouth areas than that of open water area in the eastern part of the lake, and that of bays and outflow river mouth areas. This distribution pattern belongs to Turbidity Flood Model. These heavy metals are highly related with each other positively, indicating that they are from the same pollution source. The geo-accumulation index (I(geo)) and the Hakanson potential ecological risk index were applied for assessing the status of sediment heavy metal enrichment and the extent of potential ecological risk. The pollution extent of heavy metals followed the order: Cd > As > Cu > Cr > Zn > Hg > Pb, while the single potential ecological risk of heavy metals followed the order: Cd > As > Hg > Cu > Pb > Cr > Zn. The pollution extent and potential ecological risk of Cd were the most serious among all heavy metals. The distribution pattern of Cd individual potential ecological risk indices is exactly the same as that of general potential ecological risk indices for all heavy metals, indicating the important contribution of Cd in the general indices. Analysis showed that heavy metal pollution and the potential ecological risk existed in three risk regions: the central open water area and outflow river mouth region (S9, S1 and S8), the northern bay region (S6) and the western bay region (S5).

[Measurement of the height and width of residual alveolar crests in low-set maxillary sinus patients with missing upper molar].

PURPOSE: Using spiral computed tomography and Simplant software to measure the width and height of residual alveolar crest of agomphious upper molar region at different levels around bottom of low-set maxillary sinus. To evaluate the impact of sex, age, agomphious duration, and cause of tooth extraction on the width and height of residual alveolar crest. METHODS: Forty-three patients with missing uppers molar and residual alveolar bone height being 4 to 6mm showed by panoramic radiographs were scanned by spiral computed tomography. 3D model of the alveolar crest and maxillary sinus were reconstructed using the images from CT scan and Simplant software. The height and width of the residual alveolar crest of agomphious upper molar region at different levels around bottom of maxillary sinus were measured. The data was analyzed with SPSS16.0 software package for Student's t test, analysis of variance(ANOVA) and Kruskal-Wallis H test. RESULTS: (1)The mean distance between the top of residual alveolar crest and the floor of sinus was (5.26±0.58)mm. (2)The difference between the width of internal bone wall and that of external bone wall at different levels above the bottom of maxillary sinus was significant(P<0.01), except for agomphious upper second molar at 3.75mm. (3)The height of residual crest and width of sinus floor decreased remarkably with age and agomphious duration(P<0.01) while the width of sinus lateral walls didn't change so much with them(P>0.05). (4)Height of residual crest of the tooth extracted due to periodontitis was obviously lower than that of the tooth extracted due to residual root(crown) or crown fracture(P<0.01). CONCLUSIONS: The height and width of residual crest change significantly with age, agomphious duration and causes of tooth extraction. However, the width of lateral walls above sinus floor do not change so much with those factors. The internal wall of maxillary sinus floor is wider than the external wall at agomphious molar. This anatomic feature may be taken into consideration during implantation. The site and direction of implant can be adjusted equally according to the age, agomphious duration and causes of tooth extraction, so that maxillary sinus augmentation can be avoided in part of patients with low-set maxillary sinus.

[Experimental study of maxillary sinus lifting with tissue engineered bone].

OBJECTIVE: To evaluate the effect of tissue engineering bone in maxillary sinus lifting. METHODS: The marrow stromal stem cells of dog were cultured in DMEM containing 100 m1/L fetal bovine serum and induced to differentiate to osteoblasts, which were then inoculated together with Bio-Oss for 5 days. Sixteen dog's bilateral maxillary sinus were elevated. One side was grafted with a compound of BMSC and Bio-Oss and the other side grafted with Bio-Oss alone. The samples were studied by gross, CT, histomorphology and histomorphometrical analysis at the 30th, 90th day after the operation. t-test was used for statistical analysis. RESULTS: In gross view and CT, new bone formation was observed in all maxillary sinus after 30 and 90 days respectively. Histomorphometrical analysis showed much more new callus in BMSC-Bio-Oss group than in Bio-Oss group (P < 0.05). CONCLUSIONS: A better effect of new bone formation could be obtained with tissue engineered bone in maxillary sinus lifting.

[Effects of osteogenic growth peptide on bone density adjacent to implant in irradiated tibia of the rabbits].

PURPOSE: To evaluate the effect of radiation and osteogenic growth peptide(OGP) on the bone density adjacent to the implants. METHODS: 24 rabbits underwent 48 implants placed in the tibia, then the rabbits were divided into one control group and two experimental groups randomly. Rabbits in one of the experimental groups were injected with OGP Sol, rabbits in the other groups were injected with normal saline; Then rabbits in the two experimental groups received radiation after the implant wound healed. 12 rabbits were sacrificed at 4 weeks and 16 weeks respectively. The samples were observed with gross, X-ray, histological examination. The data was analysed for Dunnett t test using SPSS13.0 software package. RESULTS: At 4 weeks, the bone density adjacent to the implant of the simple irradiation group was significantly less than that of the control group (P<0.05), while the difference was not significant between the irradiation and OGP group and the control group. At 16 weeks, the difference among the three groups wasn't significant. CONCLUSIONS: Radiation has considerable adverse effect on osteogenesis adjacent to the implants, while systemically administering OGP plays significant roles in the osteogensis of the irradiated rabbit tibia.