Background: Small intestinal neuroendocrine tumours (SI NETs) represent 30–50% of small bowel neoplasms and often present at an advanced stage. To date, there is relatively limited literature regarding prognostic factors affecting overall survival (OS) in stage IV disease. In addition, the prevalence of mesenteric fibrosis (MF) in SI NETs and its effect on OS have not been sufficiently explored in the literature. Aim: The primary aim of this study was to perform a large-scale survival analysis in an institutional cohort of 387 patients with metastatic (stage IV) SI NETs. The secondary aim was to provide epidemiological information regarding the prevalence of MF and to evaluate its effect on OS. Results: The median OS was 101 months (95% CI 84, 118). Age > 65 years, mesenteric metastases with and without desmoplasia, liver metastases, carcinoid heart disease (CHD) and bone metastases were associated with a significantly shorter OS, while primary tumour resection was predictive of a longer OS. The benefit of surgical resection was limited to symptomatic patients. MF was present in approximately 50% of patients with mesenteric lymphadenopathy. Elevated urinary 5-HIAA levels correlated strongly with the presence of CHD (p < 0.001) and to a lesser extent (p = 0.02) with MF. MF and CHD did not usually co-exist, suggesting that different mechanisms are likely to be involved in the development of these fibrotic complications. Conclusions: This study has identified specific prognostic factors in a large cohort of 387 patients with advanced SI NETs and has provided useful epidemiological data regarding carcinoid-related fibrotic complications.

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Electrically conducting Au-multiwalled carbon nanotube/polyaniline (Au-MWCNT/PANi) nanocomposites were synthesized by two different ways: (1) by direct mixing of MWCNT/PANi and Au nanoparticles (Au-MWCNT/PANi-1) and (2) by in situ polymerization of aniline in the presence of both MWCNTs and Au nanoparticles (Au-MWCNT/ PANi-2). The higher electrical conductivity of Au-MWCNT/PANi-2 compared with the other samples (PANi, MWCNT/PANi, Au-MWCNT/PANi-1) is supported by the red shifts of the UV-vis bands (polaron/bipolaron), the high value of the -NH+= stretch peak (Fourier transform infrared spectroscopy studies), the high % crystallinity (X-ray diffraction analysis) and more uniform dispersion of the Au NPs in the material. The performance of the samples in electromagnetic interference (EMI) shielding and microwave absorption was studied in the X-band (8-12 GHz). For all the samples, absorption was the dominant factor contributing toward the EMI shielding. Au-MWCNT/PANi-2 showed the best performance with a total shielding effectiveness of À16 dB [averaged over the X-band (GHz)] and a minimum reflection loss of À56.5 dB. The higher dielectric properties resulting from the heterogeneities because of the presence of nanofillers and the high electrical conductivity lead to the increased EMI shielding and microwave absorption. The results show the significance of both Au nanoparticles and method of synthesis on the EMI shielding performance of MWCNT/PANi composites. Figure 3. TEM images of MWCNTs (a), MWCNT/PANi (b), Au-MWCNT/PANi-1 (c) and (d) and Au-MWCNT/PANi-2 (e) and (f).Figure 7. FTIR spectra of different samples.Figure 6. UV-vis spectra of aqueous Au colloid (a); PANi and PANi composites in DMSO (b).Figure 12. Loss tangent (a) and skin depth (b) of PANi and its composites in the frequency range of 20 Hz-2 MHz.

The electrical conductivity and yield of polyaniline (PANi) were optimized using a design of experiments (DOE). PANi samples were synthesized by the chemical oxidative polymerization of aniline using methane sulfonic acid as the dopant acid and ammonium persulfate as the oxidant. The main factors in the synthesis of PANi that can affect the conductivity were identified as (i) the concentration of dopant acid, (ii) oxidant-to-monomer ratio, and (iii) the addition rate of oxidant to monomer. Using a Box-Behnken DOE method the regression equation, main effects plots, contour plots, and optimization plots for conductivity and yield were generated and analyzed. Under the optimized conditions of dopant acid concentration of 0.9M, an oxidant addition rate of 30 mL/h and an OM ratio of 0.9, PANi with a conductivity of 1.95 S/cm and yield of 95% was obtained. The observed trends in the four-point probe conductivity measurements were correlated with the polymer structure using fourier transform infrared spectroscopy, X-ray diffraction studies, and scanning electron microscopy.

Electrically conducting nanocomposites of polyaniline (PANI) with carbon-based fillers have evinced considerable interest for various applications such as rechargeable batteries, microelectronics, sensors, electrochromic displays and light-emitting and photovoltaic devices. The nature of both the carbon filler and the dopant acid can significantly influence the conductivity of these nanocomposites. This paper describes the effects of carbon fillers like carbon black (CB), graphite (GR) and muti-walled carbon nanotubes (MWCNT) and of dopant acids like methane sulfonic acid (MSA), camphor sulfonic acid (CSA), hydrochloric acid (HCl) and sulfuric acid (H 2 SO 4) on the electrical conductivity of PANI. The morphological, structural and electrical properties of neat PANI and carbon-PANI nanocomposites were studied using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), UV-Vis spectroscopy and the four-point probe technique, respectively. Thermogravimetric analysis (TGA) and X-ray diffraction (XRD) studies were also conducted for different PANI composites. The results show that PANI and carbon-PANI composites with organic acid dopants show good thermal stability and higher electrical conductivity than those with inorganic acid dopants. Also, carbon-PANI composites generally show higher electrical conductivity than neat PANI, with highest conductivities for PANI-CNT composites. Thus, in essence, PANI-CNT composites prepared using organic acid dopants are most suitable for conducting applications.