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ABSTRACT: A poly(vinyl alcohol) (PVA) based nanocomposite using fully exfoliated graphene oxide (GO) sheets and multi-walled carbon nanotubes (CNTs) were prepared via a simple procedure. It is confirmed from optical imaging that dispersion of CNTs in the PVA matrix can be significantly improved by adding GO sheets. Molecular dynamics (MD) simulations suggest that the GO-CNT interaction is strong and the complex is thermodynamically favorable over agglomerates of CNTs. The GO-CNT scroll-like structure formed with the hydrophilic outer surface of GO can be well dispersed in water. More important, a synergistic effect arises from the combination of CNT and GO, the GO-CNT/PVA composite films show superior mechanical properties compared to PVA composite films enhanced by GO or CNT alone, not only the tensile strength and Young's modulus of the composites are significantly improved, but most of the ductility is also retained. The enhanced mechanical properties of the GO-CNT/PVA composite film can be attributed to the fully exploited reinforcement effect from GO and CNT via good dispersion.
Journal of Materials Chemistry 01/2011; 21(29):10844-10851. · 5.97 Impact Factor
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ABSTRACT: The real-time identification and removal of adenomas is a cost-effective strategy to improve the prognosis of colorectal cancer. Confocal laser endomicroscopy (CLE) could provide real-time histological-level observation. We aimed to evaluate the efficacy of CLE diagnosis using a simple classification system that differentiates adenomas from non-neoplastic polyps with intravenous fluorescein staining alone.
An endoscope integrated confocal laser microscopy system was used in this study. CLE images of 35 colonic polyps, including 15 hyperplastic polyps and 20 adenomas confirmed by histology, were first evaluated to develop criteria for diagnosis of neoplastic and non-neoplastic polyps. The diagnostic criteria included goblet cell depletion, villous architecture, and microvascular alterations. We then performed a prospective study of colonic polyps found during CLE and classified them according to the established criteria. A total of 115 patients with 115 colonic polyps were included. The real-time CLE diagnosis was compared with that from histology. The stored CLE images were evaluated later by a blinded observer.
The sensitivity, specificity, positive predictive value, and negative predictive value of real-time CLE in identifying colonic adenomas were 93.9 % (95 % confidence interval [CI] 85.4 - 97.6), 95.9 % (95 % CI 86.2 - 98.9), 96.9 % (95 % CI 89 - 99), and 92.2 % (95 % CI 81 - 97), respectively, compared with histological results. Interobserver agreement between real-time and post-CLE still-image evaluation was excellent (kappa = 0.929). Goblet cell depletion alone had a sensitivity of 84.9 % (95 % CI 73 - 92) and a specificity of 87.8 % (95 % CI 75 - 95), as well as excellent interobserver agreement (kappa = 0.824).
Endoscope integrated CLE with fluorescein staining may reliably assist in the real-time identification of colonic adenomas. Among three diagnostic categories, goblet cell depletion can be used to distinguish adenomas and hyperplastic polyps.
Endoscopy 10/2010; 43(2):87-93. · 5.21 Impact Factor
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ABSTRACT: Confocal laser endomicroscopy (CLE) allows subsurface imaging of gastrointestinal mucosa in vivo. The goal of the present study was to compare the endomicroscopic characteristics of cells and intrapapillary capillary loops (IPCLs) in normal and superficial esophageal squamous cell carcinoma (SESC).
We recruited consecutive patients with SESC diagnosed by conventional endoscopy and confirmed by histopathology between July 2006 and May 2008. The confocal endoscopic images of these patients were collected and compared with the corresponding histology. The characteristic patterns of cells and IPCLs was then analyzed from these images of malignant and normal mucosa. The quality of images and interobserver variations of two endoscopists were also evaluated.
Overall, 64 samples from 57 subjects (27 SESCs, 30 controls) were examined by CLE. The confocal images corresponded to the hematoxylin and eosin staining from the same sites. The confocal images showed that there was a significantly higher proportion of squamous epithelial cells with irregular arrangement (79.4 % vs. 10.0 %, P < 0.001), increased diameter of IPCLs (26.0 microm vs. 19.2 microm, P < 0.001), and irregular shape IPCLs (82.4 % vs. 36.7 %, P = 0.0002) in the SESC group compared with the controls. Massive IPCLs with tortuous vessels (44.1 % vs. 0 %, P < 0.0001), and long branching IPCLs (23.5 % vs. 3.3 %, P = 0.0204) were frequently observed in the SESC group. In this study, about 35.5 % of images were graded as good quality, and the interobserver agreement for the prediction of cancerous mucosa was graded as substantial.
CLE can be used to distinguish cancerous from normal epithelium, which gives it potential value for early detection of esophageal carcinoma. The difficulty in obtaining good images in the esophagus by CLE is a latent problem.
Endoscopy 02/2009; 41(2):99-106. · 5.21 Impact Factor
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ABSTRACT: Gastric intestinal metaplasia (GIM) is a risk factor for development of intestinal-type gastric cancer. We aimed to assess the usefulness of confocal laser endomicroscopy (CLE) in diagnosing GIM.
28 patients with known GIM underwent CLE, and CLE criteria for diagnosis of GIM were developed. In addition, 53 consecutive patients with known or suspected GIM were prospectively evaluated.
GIM was identified if any of the following three features were present in an image field: goblet cells, columnar absorptive cells and brush border, and villiform foveolar epithelium. GIM was then classified as complete or incomplete according to the shape of the goblet cells, the presence of absorptive cells or brush border, and the architecture of vessels and crypts. In a prospective study, a total of 13 670 CLE images were obtained. Among 267 sites from 53 patients, 160 from 36 patients were diagnosed histopathologically as GIM. The sensitivities of conventional endoscopy and CLE for GIM were 36.88 % vs. 98.13 %, and the specificities were 91.59 % vs. 95.33 %, respectively. The kappa value for the correlation with histological findings was 0.25 for conventional endoscopy vs. 0.94 for CLE. The sensitivity and specificity of CLE were 68.03 % and 89.66 %, respectively, for the diagnosis of complete GIM, and 68.42 % and 83.41 %, respectively, for incomplete GIM; the kappa value for the correspondence between CLE and histological findings was 0.67.
CLE is a useful and potentially important method for the diagnosis and classification of GIM in vivo.
Endoscopy 08/2008; 40(7):547-53. · 5.21 Impact Factor
