Enhancing the Electrical Conductivity and Strength of PET by Single-Wall Carbon Nanotube Film Coating.

Single-wall carbon nanotubes (SWCNTs) with excellent physicochemical properties are considered a promising candidate for the electrical and mechanical reinforcements of polymers. However, the poor dispersion of SWCNTs in plastics seriously limits their application and their achieved performance enhancement. Here, we coat a freestanding, highly conductive SWCNT film onto the surface of a polyethylene terephthalate (PET) film by a hot-pressing method. Due to the uniform SWCNT network structure and strong interfacial interaction, the SWCNT/PET hybrid film showed notably enhanced electrical and mechanical properties even though with a very low SWCNT weight fraction of 0.066%. The surface square resistance of the SWCNT/PET film decreased to 120-140 Ω/□ from 1016 Ω. In addition, Young's modulus and tensile strength of the SWCNT/PET film reached 4.6 GPa and 148 MPa, which are 31.3 and 24.4%, respectively, higher than the pure PET film. The SWCNT/PET film shows excellent mechanical durability and thermal stability, demonstrating its potential use as an antistatic material.

Single-Walled Carbon Nanotube/Copper Core-Shell Fibers with a High Specific Electrical Conductivity.

Carbon nanotube (CNT)/Cu core-shell fibers are a promising material for lightweight conductors due to their higher conductivity than pure CNT fibers and lower density than traditional Cu wires. However, the electrical properties of the hybrid fiber have been unsatisfactory, mainly because of the weak CNT-Cu interfacial interaction. Here we report the fabrication of a single-walled CNT (SWCNT)/Cu core-shell fiber that outperforms commercial Cu wires in terms of specific electrical conductivity and current carrying capacity. A dense and uniform Cu shell was coated on the surface of wet-spun SWCNT fibers using a combination of magnetron sputtering and electrochemical deposition. Our SWCNT/Cu core-shell fibers had an ultrahigh specific electrical conductivity of (1.01 ± 0.04) × 104 S m2 kg-1, 56% higher than Cu. Experimental and simulation results show that oxygen-containing functional groups on the surface of a wet-spun SWCNT fiber interact with the sputtered Cu atoms to produce strong bonding. Our hybrid fiber preserved its integrity and conductivity well after more than 5000 bending cycles. Furthermore, the current carrying capacity of the coaxial fiber reached 3.14 × 105 A cm-2, three times that of commercial Cu wires.

The roles of Rab protein family in neurological diseases.

The intracellular membrane trafficking is a complicated pathway network. Rab GTPases are key regulators of membrane trafficking that are generally considered as specific markers and indicators of various organelles and membrane trafficking in endocytic and secretory pathways. Dysfunction in axonal and endosomal transport related to Rab proteins is one of the most important causes of neurodegenerative diseases. In this review, we mainly introduce how the Rab proteins change in different neurodegenerative diseases and their regulatory roles in the pathological mechanisms of related diseases. We also discuss the relationships between mitochondrial and glial cell dysfunctions and Rab proteins. Further exploration of the regulatory roles of Rab proteins will shed lights on revealing the pathogenic mechanisms of neurological diseases and providing potential targets for the early diagnosis and treatment of neurological diseases.

Preparation, characterization and luminescence properties of core-shell ternary terbium composites SiO2(600)@Tb(MABA-Si)•L.

Two novel core-shell structure ternary terbium composites SiO2(600)@Tb(MABA-Si)·L(L:dipy/phen) nanometre luminescence materials were prepared by ternary terbium complexes Tb(MABA-Si)·L2·(ClO4)3·2H2O shell grafted onto the surface of SiO2 microspheres. And corresponding ternary terbium complexes were synthesized using (CONH(CH2)3Si(OCH2CH3)3)2 (denoted as MABA-Si) as first ligand and L as second ligand coordinated with terbium perchlorate. The as-synthesized products were characterized by means of IR spectra, 1HNMR, element analysis, molar conductivity, SEM and TEM. It was found that the first ligand MABA-Si of terbium ternary complex hydrolysed to generate the Si-OH and the Si-OH condensate with the Si-OH on the surface of SiO2 microspheres; then ligand MABA-Si grafted onto the surface of SiO2 microspheres. The diameter of SiO2 core of SiO2(600)@Tb(MABA-Si)·L was approximately 600 nm. Interestingly, the luminescence properties demonstrate that the two core-shell structure ternary terbium composites SiO2(600)Tb(MABA-Si)·L(dipy/phen) exhibit strong emission intensities, which are 2.49 and 3.35 times higher than that of the corresponding complexes Tb(MABA-Si)·L2·(ClO4)3·2H2O, respectively. Luminescence decay curves show that core-shell structure ternary terbium composites have longer lifetime. Excellent luminescence properties enable the core-shell materials to have potential applications in medicine, industry, luminescent fibres and various biomaterials fields.

Influence of citrate on phase transformation and photoluminescence properties in LaPO4 and LaPO4:Eu.

The hexagonal and monoclinic phase LaPO4 and LaPO4:Eu nanostructures have been controllably synthesized by a citrate-induced hydrothermal process at 100 °C. The crystal growth of LaPO4 nanostructures was investigated, and the phase transformation of nanostructured LaPO4 was systematically studied by varying the citrate concentration, pH value and reaction temperature. When 0.8 mmol of citrate was added into the reaction system, the hexagonal phase LaPO4 transformed into the monoclinic phase. High concentrations of citrate would lead to the formation of hexagonal phase LaPO4. The photoluminescence properties of the monoclinic phase LaPO4:Eu prepared using a citrate-induced process demonstrate that the electric dipole transition (5D0 → 7F2) is stronger than the magnetic dipole transition (5D0 → 7F1), which indicated that Eu3+ is in a site with no inversion center. The strongest emission peak of hexagonal phase LaPO4:Eu comes from 5D0 → 7F1. Furthermore, the citrate-induced hexagonal phase LaPO4:Eu has a stronger emission intensity than the hexagonal phase LaPO4:Eu prepared not using a citrate-induced process.

Toll-like receptor 4 signaling plays a role in triggering periodontal infection.

Toll-like receptors (TLRs) are a group of sensors on the surface of antigen-presenting cells, such as dendritic cells and macrophages, which recognize microbial pathogens and induce innate and adaptive immune responses. Periodontitis is an inflammatory disease characterized by the destruction of tooth-supporting structures. In order to address whether TLR4 signaling plays a role in periodontitis, we studied the gene expression change in human periodontal ligament cells (HPDLCs) in response to TLR4 ligand, lipopolysaccharide treatment by microarray analysis. Expression of TLR4 was detected in HPDLCs. Lipopolysaccharide treatment increased the expression of 12 genes (more than twofold), including TLR4, TLR5, TLR7, Pellino 1, colony stimulating factor 2 (CSF2) and IL-6. In addition, the expression of 15 genes (less than equal to twofold) was decreased, including Fos, LY64 and LY86. In addition, real-time PCR was used to confirm the change of gene expression of TLR4, IL-6 and Fos. We also showed that the upregulation of IL-6 by lipopolysaccharide treatment was TLR4-dependent. This pattern of gene expression indicates that pathogens may trigger TLR4 signaling and cause periodontitis. Manipulating TLR4 signaling may potentially become one of the recognized therapies for periodontitis.

[Study of three-dimensional model on biomechanical characteristics of mandibular fractures in different site].

OBJECTIVE: To determine the biomechanical characteristics of mandibular fractures in different site. METHODS: Nine adult mandibular specimens were measured precisely. The data was used to establish a three-dimensional model. When mandibular was under functional loading, the bending and torsion moment as well as shear force of angle, body and symphyseal fracture was calculated. The data were analyzed by Origin 6.0 software. RESULTS: Angle fracture had relatively high positive bending moment and high shear force. Body fracture had positive as well as negative bending moment and the highest torsion moments. Symphyseal fracture had only negative bending moment and relatively low shear force. CONCLUSION: Angle, body and symphyseal fractures each have a biomechanics characteristic. These biomechanics characteristic should have an important meaning in the treatment of mandibular fractures and instructing patient how to bite correctly.

[Effects of aniline and phenol on freshwater algae growth].

By the methods of bioassay, this paper studied the effects of aniline or phenol on the growth of Chlorella pyrenoidosa and Scenedesmus obiquus. The results showed that these two compounds had evident effects on the growth of test algae species. For the same species, aniline was more toxic. Under the same concentration of the compounds, S. obiquus was more sensitive than C. pyrenoidosa. These two algae species could degrade or absorb parts of the compounds, and phenol in particular, when their concentrations were lower.

[Effect of yishenqinghuo recipe on periodontal inflammation and immunity of rats with experimental periodontitis].

PURPOSE: To evaluate the effect of Yishenqinghuo recipe on periodontal inflammation and immunity of rats with experimental periodontitis. METHODS: 12 months old Spague-Dawley rats were used in this study. 78 rats were randomly divided into 4 groups. group A: control group (with no periodontitis, fed with the same dosage of saline as group D); group B: model group (with periodontitis, fed with the same dosage of saline as group D); group C: high dosage group (with periodontitis, fed with double dosage of medicine as group D); group D: equivalent dosage group (with periodontitis, fed with clinical equivalent effective dosage of medicine). After being gavaged with medicine/saline for 3 months, the periodontium was analyzed through histological slices; and the amount of CD4+T,CD8+T, the ratio of CD4+T/CD8+T, IL-2 and IL-1beta in peripheral blood were detected by flow cytometry and ELISA. All the results were analyzed by ANOVA, with the use of SAS 6.04 software package. RESULTS: It was found that the periodontal inflammation of group C and D were improved significantly; the ratio of CD4+T/CD8+T in peripheral blood for this 4 groups were 3.55 +/- 0.94, 2.42 +/- 0.75, 3.23 +/- 1.14 and 3.29 +/- 0.83; the level of IL-2 and IL-1beta were (36.03+/- 2.63/179.04 +/- 17.29) pg/ml, (25.18 +/- 3.08/306.09 +/- 13.38) pg/ml, (38.44 +/- 2.58/176.33 +/- 45.38) pg/ml and (36.81 +/- 2.45/182.13 +/- 43.97) pg/ml. Compared with group B, the ratio of CD4+T/CD8+T for group C and D was significantly rised (P < 1.05); the level of IL-2 increased significantlyand IL-1beta decreased accordingly (P < 0.01). However, there was no significant difference between group C and D (P > 0.05). CONCLUSION: From this study, we conclude that Yishenqinghuo recipe can improve the periodontal inflammation and adjust the immunity of rats with experimental periodontitis. Supported by National "Tenth Five-Year" Key Science and Technology PROject (Grant No. 2004BA720A26) and Natural Science Foundation of Shanghai Municipality (Grant No. 03Zr14081).