Biodegradable poly­(butylene succinate)/polylactide (PBS/PLA) blends with various blending ratios were prepared by melt mixing for morphological and rheological studies. Dynamic rheological measurements were performed on the blend systems and the viscoelastic responses were analyzed with several emulsion models. The results show that the PBS/PLA is an immiscible blend system with very narrow cocontinuous region and high percolation threshold. The phase inversion point could be precisely predicted by the small-amplitude oscillatory shear (SAOS) response. The Palierne model gave a better description of the viscoelastic response of PBS/PLA blends than that of the Gramespacher and Meissner (G-M) model. In addition, the interfacial tension between the two polymers was measured by several techniques, such as surface property characterizations, deformed drop retraction, and rheological approaches. The differences observed by these various methodologies were then further explored. Moreover, the melting and crystallization behaviors of the blends were also studied in order to reach a deeper insight into the relations between the phase behavior and the macroscopic thermal properties of the PBS/PLA blends.

Poly(e-caprolactone)/polylactide blend (PCL/PLA) is an interesting biomaterial because the two component polymers show good complementarity in their physical properties. However, PCL and PLA are incompatible thermodynamically and hence the interfacial properties act as the important roles controlling the final properties of their blends. Thus, in this work, the PCL/PLA blends were prepared by melt mixing using the block copolymers as compatibilizer for the studies of interfacial properties. Several rheological methods and viscoelastic models were used to establish the relations between improved phase morphologies and interfacial properties. The results show that the interfacial behaviors of the PCL/PLA blends highly depend on the interface-located copolymers. The presence of copolymers reduces the interfacial tension and emulsified the phase interface, leading to stabilization of the interface and retarding both the shape relaxation and the elastic interface relaxation. As a result, besides the relaxation of matrices (s m ) and the shape relaxation of the dispersed PLA phase (s F ), a new relaxation behavior (s b ), which is attribute to the relaxation of Marangoni stresses tangential to the interface between dispersed PLA phase and matrix PCL, is observed on the compatibilized blends. In contrast to that of the diblock copolymers, the triblock copolymers show higher emulsifying level. However, both can improve the overall interfacial properties and enhance the mechanical strength of the PCL/PLA blends as a result. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: [756][757][758][759][760][761][762][763][764][765] 2010

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MicroRNAs (miRNAs) have been frequently reported to be diagnostic biomarkers and prognostic factors for cancer. The aim of the present study was to evaluate the clinical significance of microRNA-139 (miRNA-139) in hepatocellular carcinoma (HCC). All 31 patients enrolled in the present study had received curative hepatectomy. The objective miRNA was determined using miRNA microarray. The miRNA-139 expression level in cancerous tissue specimens was measured by means of reverse transcription and quantitative polymerase chain reaction, and compared with that in 31 corresponding peritumoral non-cancerous tissues. Plasma miRNA-139 expression was also quantified. The diagnostic value of plasma miRNA-139 for differentiating patients with HCC from the ones with chronic HBV-hepatitis (CH) was analyzed. The miRNA microarray performed in 3 pairs of tissue specimens determined miRNA-139 was downregulated (p=0.017). Compared with plasma of chronic HBV-hepatitis, miRNA-139 was lowly expressed in plasma of HCC patients (p<0.010). ROC analysis of plasma miRNA-139 yielded an AUC of 0.764 (p<0.010) with sensitivity of 80.6% and specificity of 58.1% while differentiating HCC from chronic HBV-hepatitis. The diagnostic power of serum α-fetoprotein (AFP) was also evaluated. The combination of miRNA-139 and AFP improved the differentiating power. Subsequently, 31 HCC patients were divided into the low or high expression group based on plasma miRNA-139 level. Plasma miRNA‑139 expression was correlated with serum AFP (p=0.043), Edmondson-Steiner grading (p=0.038). In addition, there was a significant difference in the 1-year survival rates between the two groups (p=0.023). miRNA‑139 was downregulated in the cancerous tissue and plasma of HCC patients. Plasma miRNA‑139 is a diagnostic biomarker and prognostic factor for HCC.

During the last decade, microRNAs (miRNAs) have been identified as potential biomarkers and therapeutic targets for multiple malignancies; yet, few studies exist on intrahepatic cholangiocarcinoma (ICC). In the present study, a miRNA microarray was applied to determine the significant miRNAs involved in ICC. miR-150 was found to be significantly downregulated in ICC. We further enrolled 15 ICC patients who received radical resection to test these findings in plasma. Using quantitative reverse transcription-polymerase chain reaction (qRT-PCR), we examined and quantified the expression levels of miR-150 in tumor tissues, peritumoral noncancerous tissues and blood samples of 15 ICC patients. The diagnostic value of plasma miR-150 for differentiating patients with ICC from the age- and gender-matched controls was analyzed. For plasma samples, compared with normal controls, the level of miR-150 expression was found to be upregulated (P<0.010) in ICC patients. While differentiating ICC from normal controls, receiver operator curve (ROC) analysis of plasma miR-150 revealed the area under the curve (AUC) of 0.764 (P<0.010) with sensitivity of 80.6% and specificity of 58.1%. The diagnostic value of carbohydrate antigen 19-9 (CA19-9) and the combination of miR-150 and CA19-9 were also evaluated. We found that the combination of these two markers improved the power of screening ICC. Moreover, on the basis of the plasma miR-150 level, 15 ICC patients were divided into a low or high expression group. We found that plasma miR-150 is a potential diagnostic biomarker for ICC.

Pentachlorophenol (PCP) is an environmental pollutant of serious concern due to its high toxicity and long persistence property. Fast and sensitive detection of PCP is therefore of great interest. In this work, carbon quantum dots (QDs) are synthesized by hydrothermal reaction, and characterized by fluorescence spectrophotometer, fourier transform infrared (FT-IR) spectroscopy, UV/vis/NIR spectrophotometer and scanning electron microscopy (SEM). The carbon QDs show stable and intensive electrogenerated chemiluminescence (ECL) in the presence of the coreactant S2O8(2-). Under the scanning potential of -1.2 to 0.5 V, PCP reacts with the excited C˙(-), resulting in a decrease in ECL. The detection of trace level PCP is therefore achieved using the carbon QDs and Pt working electrode. Parameters that may affect the ECL intensity including the pH of solution, ionic strength, concentrations of coreactant and carbon QDs are optimized. Under the optimal conditions, a detection limit of 1.3 × 10(-12) g L(-1) is achieved with a linear range of 10 pg L(-1)∼1.0 μg L(-1).

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The selective localization of carbon nanotubes (CNTs) in an immiscible polymer blend has attracted much attention. If the two component polymers could react with each other, do selectively located CNTs affect those reactions? Here, an immiscible polyester blend based on polycarbonate/poly(trimethylene terephthalate) (PC/PTT) is studied. CNTs introduced during melt mixing are selectively located in the PTT phase and on the phase interface during the middle stage of melt mixing. The interface‐located CNTs can act as additional substrate to catalyze or even participate in the transesterification themselves, homogenizing the phase morphology of the matrix blend. The degree of randomness of the composite systems is increased, accompanied by a reduced number‐average length of the copolymer sequences. magnified image