scholarly journals Developing Predictive Models for Carrying Ability of Micro-Plastics towards Organic Pollutants

Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1784 ◽  
Author(s):  
Xiaoxuan Wei ◽  
Miao Li ◽  
Yifei Wang ◽  
Lingmin Jin ◽  
Guangcai Ma ◽  
...  
Keyword(s):  
Organic Pollutants ◽  
Predictive Models ◽  
Adsorption Mechanism ◽  
Pure Water ◽  
Predictive Ability ◽  
Critical Issue ◽  
Induced Dipole ◽  
Kd Values ◽  
Water Partition Coefficient ◽  
Hydrogen Bond Basicity

Microplastics, which have been frequently detected worldwide, are strong adsorbents for organic pollutants and may alter their environmental behavior and toxicity in the environment. To completely state the risk of microplastics and their coexisting organics, the adsorption behavior of microplastics is a critical issue that needs to be clarified. Thus, the microplastic/water partition coefficient (log Kd) of organics was investigated by in silico method here. Five log Kd predictive models were developed for the partition of organics in polyethylene/seawater, polyethylene/freshwater, polyethylene/pure water, polypropylene/seawater, and polystyrene/seawater. The statistical results indicate that the established models have good robustness and predictive ability. Analyzing the descriptors selected by different models finds that hydrophobic interaction is the main adsorption mechanism, and π−π interaction also plays a crucial role for the microplastics containing benzene rings. Hydrogen bond basicity and cavity formation energy of compounds can determine their partition tendency. The distinct crystallinity and aromaticity make different microplastics exhibit disparate adsorption carrying ability. Environmental medium with high salinity can enhance the adsorption of organics and microplastics by increasing their induced dipole effect. The models developed in this study can not only be used to estimate the log Kd values, but also provide some necessary mechanism information for the further risk studies of microplastics.

Abstract 17114: CHA 2 DS 2 -VASc Score is a Poor Predictor of Thromboembolic Events in Heart Failure Patients With and Without Atrial Fibrillation

Circulation ◽  
2018 ◽  
Vol 138 (Suppl_1) ◽  
Author(s):  
Harold Rivner ◽  
George R Marzouka ◽  
Fei Tang ◽  
Jeffrey J Goldberger
Keyword(s):  
Heart Failure ◽  
Atrial Fibrillation ◽  
Predictive Models ◽  
Retrospective Cohort ◽  
Predictive Ability ◽  
Thromboembolic Events ◽  
Poor Predictor ◽  
Baseline Characteristics ◽  
Event Rates

Introduction: Recent evidence suggests that the CHA 2 DS 2 -VASc score could be used to predict thromboembolic events (TE) (both CVA and noncerebral thromboembolism) in heart failure (HF) patients without atrial fibrillation (AF). This non-American cohort study had several limitations. We performed a retrospective analysis using the national Veteran Affairs database to externally validate the findings. Hypothesis: The CHA 2 DS 2 -VASc score can be used equally to predict TE in HF patients with or without AF. Methods: A retrospective cohort of the national Veteran’s Affairs database was used to identify HF patients discharged between 2002-2010. Rates for TE were calculated at both 1 and 5 years. C-statistics were calculated to test the performance of CHA 2 DS 2 -VASc in predicting the rate of TE in HF patients with and without AF. Patients who developed AF during the follow-up period (crossovers) and those on anticoagulation where excluded. Negative predictive value was calculated using cutoff value of 1. Results: A total of 77,601 patients were included in this analysis: 51,667 without AF and 15,630 with AF. 10,294 crossover patients were excluded. Baseline characteristics and medications are listed in Table 1. Event rates are reported in Table 2—there is a small trend towards higher incidence with increasing score in both groups. However, C-statistics were overall poor but similar for predicting TE in both groups (Table 3) Conclusion: Our analysis suggests CHA 2 DS 2 -VASc is a poor predictive model for TE in HF with or without AF. We found that previous conclusions regarding the predictive ability of CHA 2 DS 2 -VASc are not generalizable to our large American cohort. Like previously published studies, we show that the predictive ability of CHA 2 DS 2 -VASc was similar in both HF patients with or without AF, despite excluding patient receiving anticoagulation. This suggests that AF may not be the main predictor of TE in HF patients. There is a need for better predictive models for TE in HF.

QSPR Study on n-Octanol/Water Partition Coefficient of PCDD/Fs by Three-Dimensional Holographic Vector of Atomic Interaction Field

2011 ◽  
Vol 356-360 ◽  
pp. 83-88 ◽  
Author(s):  
Shu Qiao ◽  
Kun Xie ◽  
Chuan Fu ◽  
Jie Pan
Keyword(s):  
Partition Coefficient ◽  
Organic Pollutants ◽  
Three Dimensional ◽  
Qsar Model ◽  
Atomic Interaction ◽  
Structure Property ◽  
Qspr Model ◽  
Chemical Structures ◽  
Interaction Field ◽  
Water Partition Coefficient

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are a group of important persistent organic pollutants. Quantitative structure–property relationship (QSPR) modeling is a powerful approach for predicting the properties of environmental organic pollutants from their structure descriptors. In this study, a QSPR model is established for estimating n-octanol/water partition coefficient (log KOW) of PCDD/Fs. Three-dimensional holographic vector of atomic interaction field (3D-HoVAIF) is used to describe the chemical structures, SMR-PLS QSAR model has been created and good correlation coefficients and cross-validated correlation coefficient is obtained. Predictive capability of the models has also been demonstrated by leave-one-out cross-validation. Moreover, the estimated values have been presented for those PCDD/Fs which are lack of experimentally data by the optimum model.

Development of predictive models for silicone rubber–water partition coefficients of hydrophobic organic contaminants

2019 ◽  
Vol 21 (12) ◽  
pp. 2020-2030
Author(s):  
Huichao Sun ◽  
Xianhai Yang ◽  
Xuehua Li ◽  
Xiaochen Jin
Keyword(s):  
Partition Coefficient ◽  
Organic Compounds ◽  
Silicone Rubber ◽  
Predictive Models ◽  
Organic Contaminants ◽  
Partition Coefficients ◽  
Hydrophobic Organic Compounds ◽  
Hydrophobic Organic Contaminants ◽  
Water Partition Coefficient ◽  
Qsar Models

The developed TLSER and QSAR models can be used to predict silicone rubber (passive sampler material)–water partition coefficient (Ksrw) of hydrophobic organic compounds (HOCs).

Separation of thorium(IV) from aquatic media using magnetic ferrite nanoparticles

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sarah Alharthi
Keyword(s):  
Adsorption Mechanism ◽  
Environmental Control ◽  
Critical Issue ◽  
Environmental Safety ◽  
Ferrite Nanoparticles ◽  
Nuclear Industry ◽  
Good Separation ◽  
The Sustainable Development ◽  
Pseudo Second Order ◽  
Wastewater Samples

Abstract The separation and recovery of thorium from monazite is critical to the sustainable development of the nuclear industry as well as to environmental safety. Also, the removal of radionuclides from polluted sources is a critical issue in environmental control. Magnetic ferrite nanoparticles (MCMF-NP, Co0.5Mn0.5Fe2O4) were synthesized (4–22 nm in size) and characterized. MCMF-NP was investigated for Th(IV) separation from their aqueous medium under various test conditions of acidity, time, and Th(IV) concentration, in line with the uptake capacity. The amount of thorium adsorbed is improved when pH, time, and initial concentration are increased. The maximum uptake of Th(IV) by MCMF-NP was observed at pH 3.5–4 and a contact time of 180 min. A favorable adsorption mechanism was shown in the pseudo-second-order rate. Isotherm analysis shows an adequate process described by the Langmuir isotherm. MCMF-NP is an adsorbent capable of successful disposal of Th(IV) from waste solutions with a high uptake of 81.3 mg of Th(IV)/g of MCMF-NP. The possibility of re-using the MCMF-NP, adding value to this content as a way of compensating for the disposal costs, was studied and disused. MCMF-NP shows a good separation of thorium(IV) from monazite leach liquor as well as from wastewater samples.

The effects of humic substances on the intake of micro-organic pollutants into the aquatic biota

2003 ◽  
Vol 47 (7-8) ◽  
pp. 117-124 ◽  
Author(s):  
J. Matsubara ◽  
J. Takahashi ◽  
K. Ikeda ◽  
Y. Shimizu ◽  
S. Matsui
Keyword(s):  
Humic Acid ◽  
Partition Coefficient ◽  
Humic Substances ◽  
Organic Pollutants ◽  
Living Cell ◽  
Aqueous Environment ◽  
Aquatic Biota ◽  
Filtration Membrane ◽  
Water Partition Coefficient ◽  
Ultra Filtration

Humic substances, naturally occurring highly polymerized organic compounds, exist widely in the water and soil environments. It has been known that the humic substances affect the fate of micro-organic pollutants (e.g. intake, accumulation, movement, degradation, toxicity, etc.). Of these, the effect of humic substances on the intake into biota (i.e. living cell) is one of the most important. In this research, the effects of co-existing humic substances on the intake of micro-organic pollutants into aquatic biota were experimentally evaluated. The humic acid filtrate using a 3,000 Da ultra-filtration membrane was used. Two PAHs (i.e. pyrene and phenanthrene) were used as micro-organic pollutants. Liposome for simulating living cell membrane was synthesized in the laboratory, and used for investigating the intake of micro-organic pollutants into aquatic biota precisely. The batch experiment results (PAHs onto humic acid, humic acid into liposome, and PAHs into liposome (Klipw)) led to the fact that the sorption of PAHs into liposome is suppressed apparently by binding with humic acid in the aqueous phase. This suggests that the accumulation and/or toxicity of micro-organic pollutants is retarded by humic substances in the actual aqueous environment. Moreover, the experimental results indicated that the sorption into liposome (i.e. liposome/water partition coefficient (Klipw)) could be a better parameter for estimating the intake of micro-organic pollutants into aquatic biota than n-octanol/water partition coefficient (Kow) in the aqueous environment.

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