In Vivo Classification and Characterization of Carotid Atherosclerotic Lesions with Integrated 18F-FDG PET/MRI.

BACKGROUND: The aim of this study was to exploit integrated PET/MRI to simultaneously evaluate the morphological, component, and metabolic features of advanced atherosclerotic plaques and explore their incremental value. METHODS: In this observational prospective cohort study, patients with advanced plaque in the carotid artery underwent 18F-FDG PET/MRI. Plaque morphological features were measured, and plaque component features were determined via MRI according to AHA lesion-types. Maximum standardized uptake values (SUVmax) and tissue to background ratio (TBR) on PET were calculated. Area under the receiver-operating characteristic curve (AUC) and net reclassification improvement (NRI) were used to compare the incremental contribution of FDG uptake when added to AHA lesion-types for symptomatic plaque classification. RESULTS: A total of 280 patients with advanced plaque in the carotid artery were recruited. A total of 402 plaques were confirmed, and 87 of 402 (21.6%) were symptomatic plaques. 18F-FDG PET/MRI was performed a mean of 38 days (range 1-90) after the symptom. Increased stenosis degree (61.5% vs. 50.0%, p < 0.001) and TBR (2.96 vs. 2.32, p < 0.001) were observed in symptomatic plaques compared with asymptomatic plaques. The performance of the combined model (AHA lesion type VI + stenosis degree + TBR) for predicting symptomatic plaques was the best among all models (AUC = 0.789). The improvement of the combined model (AHA lesion type VII + stenosis degree + TBR) over AHA lesion type VII model for predicting symptomatic plaques was the highest (AUC = 0.757/0.454, combined model/AHA lesion type VII model), and the NRI was 50.7%. CONCLUSIONS: Integrated PET/MRI could simultaneously evaluate the morphological component and inflammation features of advanced atherosclerotic plaques and provide supplementary optimization information over AHA lesion-types for identifying vulnerable plaques in atherosclerosis subjects to achieve further stratification of stroke risk.

Flexible fabrication chitosan-polyamidoamine aerogels by one-step method for efficient adsorption and separation of anionic dyes.

Chitosan in situ grown polyamidoamine (CTS-Gx PAMAM (x = 0, 1, 2, 3)) aerogels were fabricated by a facile one-step freeze-drying method, with glutaraldehyde serving as a crosslinker. The three-dimensional skeletal structure of aerogel provided numerous adsorption sites and accelerated the effective mass transfer of pollutants. The adsorption kinetics and isotherm studies of the two anionic dyes were consistent with the pseudo-second-order and Langmuir models, indicating that the removal of rose bengal (RB) and sunset yellow (SY) was a monolayer chemisorption process. The maximum adsorption capacity of RB and SY reached 370.28 mg/g and 343.31 mg/g, respectively. After five adsorption-desorption cycles, the adsorption capacities of the two anionic dyes reached 81.10% and 84.06% of the initial adsorption capacities, respectively. The major mechanism between the aerogels and dyes was systematically investigated based on using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and energy-dispersive spectroscopy analyses, confirming that electrostatic interaction, hydrogen bonding and van der Waals interactions were the main driving forces for the superior adsorption performance. Furthermore, the CTS-G2 PAMAM aerogel exhibited good filtration and separation performance. Overall, the novel aerogel adsorbent possesses excellent theoretical guidance and practical application potential for the purification of anionic dyes.

Hyperbranched polyamidoamine-chitosan polyelectrolyte gels crosslinking by polyacrylic acid and alginate for removal of anionic dyes.

Difficult-to-treat wastewater discharged from printing and dyeing industries has posed an environmental risk. Three-dimensional porous structures exhibit excellent dye adsorption properties. In this study, chitosan (CTS) was introduced in situ on polyamidoamine (PAMAM). Then, the composite gels containing sodium alginate (SA)/CTS in situ grown on PAMAM/polyacrylic acid (SCPP-Gn (n = 0,1,2,3)) were prepared with a controllable structure using a semi-dissolution acidification sol-gel transition method (SD-A-SGT). Owing to the stronger mechanical strength and larger specific surface area, the SCPP-G2 composite gel has the higher stability and the greater adsorption capacity for dyes, with maximum adsorption capacities of 325.21 mg/g for rose bengal (RB) and 222.40 mg/g for sunset yellow (SY). The mechanism study showed that the adsorption toward RB and SY was dominated by chemical adsorption. After five adsorption-desorption cycles, it was found that 70 % of the initial adsorption capacity could be retained. Our study demonstrates the great potential of the SCPP-G2 composite gel as an adsorbent in water treatment.

Preparation of PAMAM modified PVDF membrane and its adsorption performance for copper ions.

As one of the main pollutants of water pollution, the potential toxicity of heavy metal ions always threatens the safety of human and nature. Therefore, how to effectively remove heavy metal ions has become an important research topic in environmental protection. In the existing research, adsorption method is outstanding from many methods because of its high adsorption efficiency and easy operation. In this study, different generations of hyperbranched polyamide-amine (PAMAM) were grafted onto PVDF membrane to obtain the membrane with high adsorption capacity for heavy metal ions. The structure and physicochemical properties of the membranes were evaluated by means of fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (FE-SEM), element analyzer and X-ray photoelectron spectroscopy (EDX). At the same time, various factors affecting the adsorption process were studied, and it was found that the adsorption behavior of copper ion (Cu2+) on the membrane conformed to the pseudo-first-order kinetic model and Langmuir isotherm model. Moreover, after comparing the adsorption effect of the modified membranes grafted with different generations of PAMAM, it was found that the membrane grafted with the third generation PAMAM had the best adsorption when the solution pH was 5, and its maximum adsorption capacity could reach 153.8 mg/g. After five adsorption-desorption cycles, its adsorption capacity can reach 72.83% of the first test, indicating that it has good recycling performance. The results show that the adsorption membrane has good application potential and research value.

PVDF/SiO2-g-CDs blended membrane for fluorescence detection and adsorption of metal ions.

The preparation method of PVDF/SiO2-g-CDs blended membrane was that the silanized modified carbon dots (CDs) were grafted onto the PVDF/SiO2 blended membrane surface. The surface composition, morphology, hydrophilicity, fluorescence performance and metal ions adsorption performance of PVDF/SiO2-g-CDs blended membrane were studied. The fluorescence quenching effect of the membrane with Hg2+ and Fe3+ was obvious. The quenching mechanism was the complexation of metal ions with the functional groups of CDs including -NH2, -OH and -COOH. The optical detection limits of PVDF/SiO2-g-CDs blended membrane for Hg2+ was 1.6 nM in the linear range of 0.0025-20 µM, and the optical detection limits for Fe3+ was 2.1 µM in the linear range of 0.5-5000 µM. The maximum adsorption capacity of PVDF/SiO2-g-CDs blended membrane for Fe3+ was 47.04 mg·g-1. The adsorption of the membrane conformed to the pseudo-second-order kinetics and Langumir model, and belonged to monolayer chemical adsorption on the membrane surface. Through adsorption thermodynamic analysis, adsorption was a spontaneous endothermic process. The recovery rate of fluorescence and adsorption capacity could still be maintained above 82% after five cycles. The PVDF/SiO2-g-CDs blended membrane had the ability to regenerate. In summary, the PVDF/SiO2-g-CDs blended membrane had the dual functions of detecting and adsorbing metal ions, and had broad application prospects in sewage treatment.