Novel hard carbon/graphite composites synthesized by a facile in situ anchoring method as high-performance anodes for lithium-ion batteries.

In this report, novel hard carbon/graphite composites are prepared by a simple in situ particle anchoring method, followed by carbonization. The effects of loading content of hard carbon on the structure and electrochemical performance of the composites are investigated. The SEM results show that the hard carbon particles are anchored randomly on the surface of graphite. The electrochemical measurements demonstrate that an appropriate loading content of hard carbon can remarkably increase the specific reversible capacity of graphite, which is mainly contributed by lithiation in hard carbon, whereas excessive loading leads to the formation of a thick particle shell onto the surface of graphite, which deteriorates the initial coulombic efficiency drastically. Kinetic tests further show that excessive loading of hard carbon is unfavorable for lithium-ion diffusion probably due to the increased interface distance and decreased electroconductivity. The composite loaded with 10 wt% hard carbon exhibits balanced lithium storage performance with high reversible capacity of 366 mA h g-1, high initial coulombic efficiency (∼91.3%), and superior rate capability and cycling performance. Thus, in this study, we suggest a facile and effective strategy to fabricate a promising graphite anode material for high-performance lithium-ion batteries.

Entangled titanium fibre balls combined with nano strontium hydroxyapatite in repairing bone defects.

OBJECTIVE: To investigate the effect of entangled titanium fibre balls (ETFBs) combined with nano strontium hydroxyapatite (nano-Sr-HAP) on the repair of bone defects in vivo. MATERIALS AND METHODS: Twenty-four 6-month-old, specific pathogen-free, male Sprague-Dawley rats were used. Drill defects were created in bilateral femoral condyles. ETFBs combined with nano-Sr-HAP were selected randomly from 72 samples and implanted into the femoral bone defects of left legs, which served as the experimental group, while ETFBs without nano-Sr-HAP were implanted into right legs for comparison. The bone defects on both sides were X-rayed. The anteroposterior positions and histological procedures and evaluations of each sample were performed at 1, 2, 4 and 8 weeks post-surgery. RESULTS: Histological results showed that the ETBs allowed new bone to grow within their structure. Additionally, an increase in new bone was seen on the nano-Sr-HAP side compared to the control side. The results of histomorphometric analysis confirmed that the new bone formation on the left side gradually increased with time. There was a statistical increase in new bone at 2, 4 and 8 weeks, and the differences between the two sides were statistically significant at weeks 4 and 8 (p < 0.05 for all comparisons). CONCLUSION: The results showed that ETFBs possess a unique 3-dimensional interconnective porous structure and have excellent biocompatibility, cell affinity and osteoconductivity, which makes them useful as scaffold materials for repairing bone defects. On the other hand, nano-Sr-HAP improved the bone defect-repairing capacity of the ETFBs, which showed osteoinductive properties.

Influence of urbanization and industrialization on metal enrichment of sediment cores from Shantou Bay, South China.

Four sediment cores were collected to investigate geochemical sources and to assess enrichment and pollution of metals in sediments from Shantou Bay, an area experiencing rapid economic development on the Southeastern Coast of China. The results indicated that the concentrations of the majority of metals showed a decrease with depth, with overall maximum values in the top layers, and that different sampling locations in the Bay received slightly different types of inputs. Three major sources were identified by correlation analysis and principal component analysis: river inputs, metropolitan, and port facilities discharge. Calculation of a pollution load index revealed overall low values, but the enrichment factor values for Pb and Cd were typically high for all cores. The mean concentrations of Cu, Pb, Zn and to some extent Cd exceeded the Effects-Range-Low values in the majority of the cases, indicating that there were possible ecotoxicological risks to organisms in Shantou Bay.

Distribution and accumulation of heavy metals in surface sediments from a subtropical bay affected by the Special Economic Zone, China.

The concentrations of nine metals (Cd, Cr, Cu, Ni, Mn, Pb, Zn, Fe, and Al) in surface sediments from 14 sampling sites in Shantou Bay were determined in order to understand current metal levels and spatial distribution due to the rapid development of the Shantou Special Economic Zone. Results showed that metal concentrations in surface sediments varied from 0.31 to 1.74 mg kg(-1) for Cd, 35.98 to 74.19 mg kg(-1) for Cr, 24.43 to 79.24 mg kg(-1) for Cu, 428.45 to 809.87 mg kg(-1) for Mn, 16.91 to 31.51 mg kg(-1) for Ni, 35.59 to 64.84 mg kg(-1) for Pb, 84.91 to 246.51 mg kg(-1) for Zn, 2.93 to 3.93% for Fe, and 5.25 to 9.28% for Al. Although all metal concentrations in sediments meet Chinese National Standard Criteria for Marine Sediment Quality, both enrichment factor (EF) and geo-accumulation index (Igeo) show Pb and Cd pollution existed in the upper and middle bay, and pollution of other metals is also recorded in some sites depending on the sources; river input, sewage discharge, and port activities are the main sources of pollutant to the bay.

Distribution and geochemical speciation of heavy metals in sediments from coastal area suffered rapid urbanization, a case study of Shantou Bay, China.

Eight metals in sediment samples at 15 sites from the Shantou Bay were analyzed with BCR sequential extraction protocol to obtain the metal distribution patterns in the bay. The results showed that the heavy metal pollutions in upper bay were more severe than in middle and down reaches of the bay. Both total and non-residual fractions of metals with a exception of Mn showed a seaward decrease trend. More than 54% of the total concentrations of Cd, Mn and Zn existed in the acid soluble fraction. Ni, Co, Cr and Fe mainly (more than 51%) occurred in the residual fraction. While Pb and Cu dominantly presented in the reducible (50%) and oxidable (33%) fraction respectively. Principal component analysis (PCA) revealed that the heavy metals in the non-residual fractions resulted from largely anthropogenic sources, including river input, city runoff and port discharge. These contributing sources are highlighted by cluster analysis.

[Distribution characteristics of phosphorus forms in surface sediments of the Shantou Bay in China].

In order to know the horizontal distribution and seasonal variation characteristics of phosphorus species in surface sediment, the contents of different phosphorus species in the surface sediment sampling from Shantou Bay were determined by using the SMT sequential extraction method in September and November, 2008, and June, 2009. The contents of different phosphorus species basically showed an order of the low-water period, normal-water period and high-water period from high to low, and horizontal distributions of phosphorus species showed a decrease trend as waves from the inner bay to the outer bay with the maximum appeared in Niutianyang. The main form of total phosphorus in sediment was inorganic phosphorus, which accounted for 94.06%, and the content of Ca-P was the highest in all inorganic phosphorus of the surface sediment in Shantou Bay, comprising 70.21%, followed by Ads-P, Fe-P and De-P. The correlation analysis among different phosphorus forms suggested that they had similar sources and they were affected by surface runoff and seasonal variation. OP, Fe-P and Ads-P were bioavailable phosphorus, which were controlled by sources and water oxidation-reduction potential; while Ca-P and De-P were mainly influenced by biological processes and geological characteristics.

Preservation of disc for treatment of traumatic temporomandibular joint ankylosis.

PURPOSE: A new operating method was used to treat traumatic temporomandibular joint (TMJ) ankylosis, to restore the structure of the TMJ, to improve the secondary maxillofacial deformity, and prevent recurrence of TMJ ankylosis. PATIENTS AND METHODS: Thirty-six patients (20 females, 16 males; aged 5 to 54 years old) with TMJ ankylosis type II or III of 1 to 16 years' duration, with a maximal mouth opening from 0 to 15 mm preoperatively participated. The new method was to separate bony fusion between condyle and glenoid fossa, remove the condylar fragment that displaced medially or anteroinferiorly, mobilize the remains of the disc over the condylar stump and suture it with articular capsule, and shave the surface of the condylar stump and glenoid fossa smooth. RESULTS: Follow-up was performed from 1 to 7 years postoperatively in 21 cases. No recurrences occurred in patients whose TMJ disc was retained during operation. Patients had an average maximal mouth opening of 33.7 mm postoperatively. An 11-year-old patient showed an improved facial symmetry after surgery. CONCLUSION: By restoring the normal structure of the TMJ and preservation of the disc, recurrence of traumatic TMJ ankylosis and facial deformity in younger patients can be prevented.