The development of conductive polymer composites remains an important endeavor in light of growing energy concerns. A conducting polymer composite in the presence of plasticized carbon black (CB) and epoxy resin has been developed. Room temperature electrical conductivity, mobility carriers (μ), and number of charges (N) increase by increasing CB content. Electrical conductivity–temperature dependence of the composite was investigated and negative temperature coefficient of conductivity (NTC) behavior of the composites was revealed. The mechanism of the NTC effect in materials is related to the thermal expansion of the epoxy matrix and barriers height energy. The current–voltage behavior of epoxy/CB composites shows a switching effect and the mechanism of negative resistance is interpreted in details. Thermal conductivity (γ) increases with increasing filler content and the experimental data was compared with a theoretical model based on energy balance equation. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers

The network structure, mechanical properties, and thermal gravimetric of epoxy resin filled with plasticized carbon black (CB) have been studied. The effect of CB concentration on composite morphology as well as cross linking density (n), volume fraction of resin (V r ), degree of crystallinity (X c ), mean gap among conductive particles (g), aspect ratio (F), and mechanical property such as modulus of elasticity (Y m ), hardness (H A ), and elongation at break (EB) have been examined and correlated to establish structure-property relationships. According to the thermal gravimetric analysis, the thermal decomposition of the composite took place at a slightly higher temperature than that of green epoxy. It proved that the inclusion of plasticized CB improves the quality of the network structure and enhances the mechanical properties of the composites. POLYM. COMPOS.,

In this study, we aimed to evaluate serum cystatin C (sCysC) as an early predictor of acute kidney injury (AKI) in preterm neonates with respiratory distress syndrome (RDS). Sixty preterm neonates diagnosed with RDS and 40 healthy controls (28-36 weeks) admitted to the neonatal Intensive Care Unit were investigated. AKI was defined on the 3rd day of life (DOL-3) as an increase in serum creatinine (sCr) of >0.3 mg/dL from baseline (the lowest previous sCr). sCysC levels were measured on DOL-1, -3 and -7. Of the 60 neonates with RDS, 24 (40%) developed AKI. Five patients (79.17%) were classified as AKI Network (AKIN-1) and 19 patients (20.83%), as AKIN-2. At DOL-3, the mean sCysC values were significantly higher among neonates with RDS and AKI (1.68 ± 0.37) compared with controls (0.79 ± 0.83) and those with RDS and no AKI (0.85 ± 0.20) (P <0.001). sCysC levels significantly increased among neonates with AKI from DOL-3 to DOL-7 (P = 0.002). The sCr values showed no significant difference between those with RDS with AKI, RDS, and no AKI or control groups at DOL-1 and -3. Only as late as DOL-7, the mean values of sCr were higher among neonates with AKI compared with no AKI and controls (P <0.001). The receiver operating characteristic curves area under the curve was 0.97 for predicting the development of AKI within 72 h (P = 0.001). With the best cutoff value of ≥1.28 mg/L, the sensitivity and specificity of sCysC for detecting AKI within 72 h were 100 and 83.3%, respectively. In conclusion, sCysC is an early marker for AKI in neonates with RDS.