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Abstract We developed a novel one-pot polyol approach for the synthesis of biocompatible CdSe quantum dots (QDs) using poly(acrylic acid) (PAA) as a capping ligand at 240°C. The morphological and structural characterization confirmed the formation of biocompatible and monodisperse CdSe QDs with several nanometers in size. The encapsulation of CdS thin layers on the surface of CdSe QDs (CdSe/CdS core–shell QDs) was used for passivating the defect emission (650 nm) and enhancing the fluorescent quantum yields up to 30% of band-to-band emission (530–600 nm). Moreover, the PL emission peak of CdSe/CdS core–shell QDs could be tuned from 530 to 600 nm by the size of CdSe core. The as-prepared CdSe/CdS core–shell QDs with small size, well water solubility, good monodispersity, and bright PL emission showed high performance as fluorescent cell labels in vitro. The viability of QDs-labeled 293T cells was evaluated using a 3-(4,5-dimethylthiazol)-2-diphenyltertrazolium bromide (MTT) assay. The results showed the satisfactory (>80%) biocompatibility of as-synthesized PAA-capped QDs at the Cd concentration of 15 μg/ml.

Detection of divalent mercury attracts great significance in most biological and environmental systems. In this study, a Thymine-divalent mercuric ions-Thymine (T-Hg2+-T) structure based colorimetric assay with Exonuclease III (Exo III) assisted recycling and G-quadruplex-hemin DNAzyme amplification is put forward for Hg2+ monitoring. The Hg2+ can combine with T-T mismatches of oligo-1 to form T-Hg2+-T base pairs, which brings forth a double-helix structure with a blunt terminus. Short mononucleotide fragment (trigger DNA) and Hg2+ could be released as the double-helix structure in oligo-1 is cleaved by Exo III. The released Hg2+ can be captured by another oligo-1, and generate the new cycles. At the same time, signal DNA (oligo-2) can hybridize with trigger DNA to form double-stranded DNA with a blunt terminus that can be cleaved by Exo III to accrue the trigger DNA and guanine (G)-quadruplex fragment. The trigger DNA can hybridize with another signal DNA, which implements the dual-recycling amplification. The G-quadruplex fragment can form the G-quadruplex-hemin DNAzymes, which can catalyze the oxidation of 2, 2ʹ-azino-bis(3-ethylbenzothiazo-line-6-sulfonate) disodium salt (ABTS2-) by H2O2. The color change, served as the signal output, can be measured with an ultraviolet spectrophotometer. The proposed assay allows Hg2+ to be detected in the range of 25 pM to 2000 pM with a detection limit of 7 pM. Moreover, it has been commendably applied to the determination of Hg2+ in environmental samples and biological samples. [ABSTRACT FROM AUTHOR]

Gold (Au)–cadmium sulfide (CdS) nanocomposites have attracted widespread attention for semiconductor-based photocatalysis applications. Understanding the dynamic behaviours of Au–CdS nanoclusters (NCs) in liquid solution is critical for fine control of the Au–CdS composite structure, and helps the design and development of future materials with improved catalytic properties. Here, we report the direct observation of the dynamic behaviours of Au and CdS NCs in water and in N,N-dimethylformamide (DMF) aqueous solution by in situ liquid cell transmission electron microscopy (LC-TEM). Electron beam induced liquid motion/bubble formation is found to be effective in guiding the NCs' motion and interaction behaviours. The Au and CdS NCs combined better with each other in the DMF aqueous solution than in pure water. Around a thicker DMF solution region, liquid droplets keep growing, and show an overlap-like phenomenon in the TEM images due to their 3-D morphologies. The proceeding liquid solution front can further facilitate the lighter CdS to dynamically approach and connect with the heavier Au NCs. On the other hand, in the thinner DMF solution regions, electron beam irradiation not only caused bubble formation and growth, but also induced dissolution of the CdS in the composite. These results can provide in-depth understanding of nanoscale liquid–solid interactions for the development of future semiconductor–metal composite structures. [ABSTRACT FROM AUTHOR]

Background: The aim of this study is to assess the validity of the measurement of pepsinogen as a screening test for chronic atrophic gastritis (AG) in health check-up populations in China.Methods: Patients from consecutive regular health check-up were enrolled from January 2014 to June 2015. Endoscopy, combined with monitoring the Helicobacter pylori (Hp) infections, and measuring the serum pepsinogen (PG) were used to determine the diagnostic accuracy of PG for the screening of atrophic gastritis. Histopathology was assessed by the Operative Link on Gastritis Assessment (OLGA) system. Statistical analysis was performed using SPSS statistical software.Results: The total Hp infection rate was 40%. Based on pathology, the 996 participants were divided into three groups: non-atrophic (NAG), mild-moderate atrophic (MAG): stage I and II of the OLGA classification, and severe atrophic (SAG): stage III and IV of the OLGA classification. Compared with NAG and MAG groups, PGR decreased significantly in SAG group (p < 0.05). PGI and PGII levels were significantly elevated in Hp-positive group, while the PGR was markedly decreased (p < 0.01). When MAG and SAG groups were combined and compared with NAG group, the best cutoff value for atrophy diagnosis was PGI ≤50.3 ng/ml; the cutoff value in Hp-negative group was absolutely higher than in Hp-positive group. When NAG and MAG groups were combined and compared with the SAG group, the best cutoff value for diagnosis of severe atrophy was at PGR ≤4.28. The cutoff values in Hp-negative and Hp-positive groups were calculated at PGR ≤6.28 and ≤4.28, respectively.Conclusions: Pepsinogens play an important role in the identification of patients with atrophic gastritis and severe AG. Use of different cutoff values of PG for Hp-negative and Hp-positive groups may offer greater efficacy in the diagnosis of AG. [ABSTRACT FROM AUTHOR]

Aim Of Study: For the tumor lesions close to capsule of the liver, traditional percutaneous radiofrequency ablation (PRFA) is limited due to high incidence of postoperative complications. The aim of the present study is to whether laparoscopic combined with PRFA (LCPR) could effectively ablate the tumor lesions close to capsule of the liver.Methods: A total of 119 patients with subcapsular hepatocellular carcinoma (HCC) were divided into two groups: PRFA group (89 patients) and LCPR group (30 patients). RFA was accomplished through cool-tip RFA system. For LCPR, PRFA was first carried out to destroy tumors deep inside the liver tissue. Then, laparoscopic RFA was performed under the guide of laparoscopic view and destroyed the superficial part of the tumor. Postoperative morbidity and technique effectiveness between two groups were evaluated.Results: In PRFA group, the rate of fever was 70.8% (63/89), and two patients had gallbladder damage. Five patients had ascites. Pain was found in 26 patients (29.2%). In LCPR group, the rate of fever was 22/30 (73.3%). Two patients had ascites and only two patients complained of pain. In PRFA group, 77.5% (69/89) of the tumors were totally ablated, and in LCPR, 93.3% (28/30) of the tumors were destroyed without any residuals.Conclusion: LCPR could significantly reduce the incidence of postoperative pain and the rate of regional tumor residuals compared to the PRFA, suggesting this method could potentially be useful for subcapsular HCC ablation treatment. [ABSTRACT FROM AUTHOR]

This paper presents a novel method for speckle noise removal. We propose a nonlocal low-rank regularization (NLR) approach toward exploiting structured sparsity and explore its application into speckle noise removal. A nonconvex surrogate functions for the rank instead of the convex nuclear norm is proposed. To further improve the computational efficiency of the proposed algorithm, we have developed a fast implementation using augmented Lagrange multiplier (ALM) method. We experimentally demonstrate the excellent performance of the technique, in terms of both Peak Signal to Noise Ratio (PSNR) and Structural Similarity (SSIM). [ABSTRACT FROM AUTHOR]