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Physical Chemistry Chemical Physics :... Aug 2023Acrylonitrile (CHCHCN) is ubiquitous in space (molecular clouds, solar-type star forming regions, and circumstellar envelopes) and is also abundant in the upper...
A combined crossed molecular beam and theorerical study of the O(P,D) + acrylonitrile (CHCHCN) reactions and implications for combustion and extraterrestrial environments.
Acrylonitrile (CHCHCN) is ubiquitous in space (molecular clouds, solar-type star forming regions, and circumstellar envelopes) and is also abundant in the upper atmosphere of Titan. The reaction O(P) + CHCHCN can be of relevance in the chemistry of the interstellar medium because of the abundance of atomic oxygen. The oxidation of acrylonitrile is also important in combustion as the thermal decomposition of pyrrolic and pyridinic structures present in fuel-bound nitrogen generates many nitrogen-bearing compounds, including acrylonitrile. Despite its relevance, limited information exists on this reaction. We report a combined experimental and theoretical investigation of the reactions of acrylonitrile with both ground P and excited D atomic oxygen. From product angular and time-of-flight distributions in crossed molecular beam experiments with mass spectrometric detection at a collision energy, , of 31.4 kJ mol, we have identified the primary reaction products and determined their branching fractions (BFs). Theoretical calculations of the relevant triplet and singlet potential energy surfaces (PESs) were performed to interpret the experimental results and elucidate the reaction mechanism. Adiabatic statistical calculations of product BFs for the decomposition of the main triplet and singlet intermediates have been carried out. Combining the experimental and theoretical results, we conclude that the O(P) reaction leads to two main product channels: (i) CHCNH (ketenimine) + CO (dominant with a BF of 0.87 ± 0.05), formed efficient intersystem crossing from the entrance triplet PES to the underlying singlet PES, and (ii) HCOCHCN + H (minor, with a BF of 0.13 ± 0.05), occurring adiabatically on the triplet PES. Our study suggests the inclusion of this reaction as a possible destruction pathway of CHCHCN and a possible formation route of CHCNH in the interstellar medium. The O(D) + CHCHCN reaction mainly leads to the formation of CHCNH + CO adiabatically on the singlet PES. This result can improve models related to the chemistry of interstellar ice and cometary comas, where O(D) reactions can play a role. Overall, our results are expected to be useful for improving the models of combustion and extraterrestrial environments.
PubMed: 37469256
DOI: 10.1039/d3cp01558k -
Regulatory Toxicology and Pharmacology... Jun 2021To conduct a systematic review and meta-analysis of lung cancer among acrylonitrile-exposed workers. (Meta-Analysis)
Meta-Analysis
PURPOSE
To conduct a systematic review and meta-analysis of lung cancer among acrylonitrile-exposed workers.
METHODS
A literature search through April 2020 was performed to identify relevant cohort and case-control studies. Data from these studies were meta-analyzed to generate summary relative risk estimates (SRREs). Heterogeneity was examined in sub-group and sensitivity analyses, and by meta-regression.
RESULTS
Twenty-two studies were reviewed systematically, and 10 cohort studies and one case-control study were meta-analyzed. Individual relative risk estimates reported across studies were heterogeneous, with most being relatively weak in statistical strength and non-statistically significant on both sides of the null value. Meta-analysis of these data resulted in an SRRE of 1.04 (95% CI: 0.89-1.21; overall model, largely consisting of all workers exposed to acrylonitrile). Sub-group analyses and meta-regression did not support patterns of positive dose-response relationships by duration of exposure/employment or cumulative exposure.
CONCLUSIONS
Although some positive associations have been reported in internal comparison analyses based on increasing exposure categories, few associations are statistically significant, there are no apparent or consistent patterns of dose-response, and the confounding influence of cigarette smoking was not adequately controlled. Thus, findings from this review and meta-analysis do not support an increased risk of lung cancer among acrylonitrile workers.
Topics: Acrylonitrile; Cigarette Smoking; Dose-Response Relationship, Drug; Humans; Lung Neoplasms; Occupational Exposure; Risk Factors
PubMed: 33617939
DOI: 10.1016/j.yrtph.2021.104896 -
International Journal of Molecular... Feb 2021New 2-(thien-2-yl)-acrylonitriles with putative kinase inhibitory activity were prepared and tested for their antineoplastic efficacy in hepatoma models. Four out of the...
New 2-(thien-2-yl)-acrylonitriles with putative kinase inhibitory activity were prepared and tested for their antineoplastic efficacy in hepatoma models. Four out of the 14 derivatives were shown to inhibit hepatoma cell proliferation at (sub-)micromolar concentrations with IC values below that of the clinically relevant multikinase inhibitor sorafenib, which served as a reference. Colony formation assays as well as primary in vivo examinations of hepatoma tumors grown on the chorioallantoic membrane of fertilized chicken eggs (CAM assay) confirmed the excellent antineoplastic efficacy of the new derivatives. Their mode of action included an induction of apoptotic capsase-3 activity, while no contribution of unspecific cytotoxic effects was observed in LDH-release measurements. Kinase profiling of cancer relevant protein kinases identified the two 3-aryl-2-(thien-2-yl)acrylonitrile derivatives and as (multi-)kinase inhibitors with a preferential activity against the VEGFR-2 tyrosine kinase. Additional bioinformatic analysis of the VEGFR-2 binding modes by docking and molecular dynamics calculations supported the experimental findings and indicated that the hydroxy group of might be crucial for its distinct inhibitory potency against VEGFR-2. Forthcoming studies will further unveil the underlying mode of action of the promising new derivatives as well as their suitability as an urgently needed novel approach in HCC treatment.
Topics: Acrylonitrile; Carcinoma, Hepatocellular; Cell Proliferation; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Hep G2 Cells; Humans; Liver Neoplasms; Molecular Docking Simulation; Molecular Structure; Protein Kinase Inhibitors; Structure-Activity Relationship; Thiophenes; Vascular Endothelial Growth Factor Receptor-2
PubMed: 33668139
DOI: 10.3390/ijms22052243 -
Sensors (Basel, Switzerland) Oct 2023Crack propagation is a critical phenomenon in materials science and engineering, significantly impacting structural integrity, reliability, and safety across various...
Crack propagation is a critical phenomenon in materials science and engineering, significantly impacting structural integrity, reliability, and safety across various applications. The accurate prediction of crack propagation behavior is paramount for ensuring the performance and durability of engineering components, as extensively explored in prior research. Nevertheless, there is a pressing demand for automated models capable of efficiently and precisely forecasting crack propagation. In this study, we address this need by developing a machine learning-based automated model using the powerful H2O library. This model aims to accurately predict crack propagation behavior in various materials by analyzing intricate crack patterns and delivering reliable predictions. To achieve this, we employed a comprehensive dataset derived from measured instances of crack propagation in Acrylonitrile Butadiene Styrene (ABS) specimens. Rigorous evaluation metrics, including Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and R-squared (R) values, were applied to assess the model's predictive accuracy. Cross-validation techniques were utilized to ensure its robustness and generalizability across diverse datasets. Our results underscore the automated model's remarkable accuracy and reliability in predicting crack propagation. This study not only highlights the immense potential of the H2O library as a valuable tool for structural health monitoring but also advocates for the broader adoption of Automated Machine Learning (AutoML) solutions in engineering applications. In addition to presenting these findings, we define H2O as a powerful machine learning library and AutoML as Automated Machine Learning to ensure clarity and understanding for readers unfamiliar with these terms. This research not only demonstrates the significance of AutoML in future-proofing our approach to structural integrity and safety but also emphasizes the need for comprehensive reporting and understanding in scientific discourse.
PubMed: 37896512
DOI: 10.3390/s23208419 -
Polymers Jan 2023This work aims to enhance the mechanical properties, oil resistance, and thermal properties of acrylonitrile butadiene rubber (NBR) by using the fish scales as a filler...
This work aims to enhance the mechanical properties, oil resistance, and thermal properties of acrylonitrile butadiene rubber (NBR) by using the fish scales as a filler and using bis(triethoxysilylpropyl)tetrasulfide (TESPT) as a coupling agent (CA). The prepared fish scale particles (FSp) are B-type hydroxyapatite and the particle shape is rod-like. The filled NBR with FSp at 10 phr increased tensile strength up to 180% (4.56 ± 0.48 MPa), reduced oil absorption up to 155%, and increased the decomposition temperature up to 4 °C, relative to the unfilled NBR. The addition of CA into filled NBR with FSp at 10 phr increased tensile strength up to 123% (5.62 ± 0.42 MPa) and percentage of elongation at break up to 122% relative to the filled NBR with FSp at 10 phr. This work demonstrated that the prepared FSp from the fish scales can be used as a reinforcement filler to enhance the NBR properties for use in many high-performance applications.
PubMed: 36772030
DOI: 10.3390/polym15030729 -
Frontiers in Chemistry 2021Process analytical technology and multivariate process monitoring are nowadays the most effective approaches to achieve real-time quality monitoring/control in...
Process analytical technology and multivariate process monitoring are nowadays the most effective approaches to achieve real-time quality monitoring/control in production. However, their use is not yet a common practice, and industries benefit much less than they could from the outcome of the hundreds of sensors that constantly monitor production in industrial plants. The huge amount of sensor data collected are still mostly used to produce univariate control charts, monitoring one compartment at a time, and the product quality variables are generally used to monitor production, despite their low frequency (offline measurements at analytical laboratory), which is not suitable for real-time monitoring. On the contrary, it would be extremely advantageous to benefit from predictive models that, based on online sensors, will be able to return quality parameters in real time. As a matter of fact, the plant setup influences the product quality, and process sensors (flow meters, thermocouples, etc.) implicitly register process variability, correlation trends, drift, etc. When the available spectroscopic sensors, reflecting chemical composition and structure, consent to monitor the intermediate products, coupling process, and spectroscopic sensor and extracting/fusing information by multivariate analysis from this data would enhance the evaluation of the produced material features allowing production quality to be estimated at a very early stage. The present work, at a pilot plant scale, applied multivariate statistical process control (MSPC) charts, obtained by data fusion of process sensor data and near-infrared (NIR) probes, on a continuous styrene-acrylonitrile (SAN) production process. Furthermore, PLS regression was used for real-time prediction of the Melt Flow Index and percentage of bounded acrylonitrile (%AN). The results show that the MSPC model was able to detect deviations from normal operative conditions, indicating the variables responsible for the deviation, be they spectral or process. Moreover, predictive regression models obtained using the fused data showed better results than models computed using single datasets in terms of both errors of prediction and . Thus, the fusion of spectra and process data improved the real-time monitoring, allowing an easier visualization of the process ongoing, a faster understanding of possible faults, and real-time assessment of the final product quality.
PubMed: 34746093
DOI: 10.3389/fchem.2021.748723 -
Waste Management (New York, N.Y.) Jul 2022The mismanagement of waste electrical and electronic equipment (WEEE) resulted in numerous discarded plastics in the natural environment, and these waste plastics might...
The mismanagement of waste electrical and electronic equipment (WEEE) resulted in numerous discarded plastics in the natural environment, and these waste plastics might experience aging, breaking, and migration, which becomes a crucial microplastic source. Sustainable management of WEEE plastics presents a considerable opportunity for resource recovery and microplastic pollution prevention. Flotation separation is a significant process of mechanical recycling, while most flotation methods can only deal with binary plastic mixtures. In this work, an advanced, stepwise, and sustainable flotation method was advocated to separate multi-plastics by polymeric aluminum chloride (PAC) modification. The abundant hydrophilic groups and environmental friendliness of PAC prompted us to further investigate the wetting effect. PAC had varied hydrophilization effects on acrylonitrile butadiene styrene (ABS) and polystyrene (PS) surfaces, but polyethylene terephthalate (PET) retained hydrophobicity. Treatment conditions, including PAC dosage, temperature, time, and pH were optimized. 100% of PET could be purified after primary separation, and the purities of ABS and PS could reach 100% and 97.4% after secondary separation, respectively. The strength of the interaction was determined by the different surface potentials and functional groups. In PAC solution, long-chain molecules or ions might interact with plastic surfaces electrostatically, and Al could bridge long-chain molecules and plastic surfaces, thereby strengthening the polymer hydrophilicity. We further improved the PAC treatment process, and the reuse of PAC reduced modifier usage to 84.4 g/ton waste plastics, which was cost-effective in industrial applications. A preliminary evaluation of the energy consumption and environmental impact indicated that PAC treatment was superior to other modification methods. This work is an initial attempt at the stepwise separation of waste plastic and shows promising prospects for recycling plastic waste.
Topics: Acrylonitrile; Aluminum Chloride; Electronics; Microplastics; Plastics; Polyethylene Terephthalates; Polymers; Polystyrenes; Recycling; Refuse Disposal
PubMed: 35689973
DOI: 10.1016/j.wasman.2022.05.029 -
Journal of Exposure Science &... Mar 2021Acrylonitrile is a possible human carcinogen that is used in polymers and formed in tobacco smoke. We assessed acrylonitrile exposure in the US population by measuring...
BACKGROUND
Acrylonitrile is a possible human carcinogen that is used in polymers and formed in tobacco smoke. We assessed acrylonitrile exposure in the US population by measuring its urinary metabolites N-acetyl-S-(4-hydroxy-2-methyl-2-buten-1-yl)-L-cysteine (2CYEMA) and N-acetyl-S-(1-cyano-2-hydroxyethyl)-L-cysteine (1CYHEMA) in participants from the 2011-2016 National Health and Nutrition Examination Survey.
OBJECTIVE
To assessed acrylonitrile exposure using population-based biomonitoring data of the US civilian, non-institutionalized population.
METHODS
Laboratory data for 8057 participants were reported for 2CYEMA and 1CYHEMA using ultrahigh-performance liquid chromatography/tandem mass spectrometry. Exclusive tobacco smokers were distinguished from non-users using a combination of self-reporting and serum cotinine data. We used multiple linear regression models to fit 2CYEMA concentrations with sex, age, race/Hispanic origin, and tobacco user group as predictor variables.
RESULTS
The median 2CYEMA level was higher for exclusive cigarette smokers (145 µg/g creatinine) than for non-users (1.38 µg/g creatinine). Compared to unexposed individuals (serum cotinine ≤0.015 ng/ml) and controlling for confounders, presumptive second-hand tobacco smoke exposure (serum cotinine >0.015 to ≤10 ng/ml and 0 cigarettes per day, CPD) was significantly associated with 36% higher 2CYEMA levels (p < 0.0001). Smoking 1-10 CPD was significantly associated with 6720% higher 2CYEMA levels (p < 0.0001).
SIGNIFICANCE
We show that tobacco smoke is an important source of acrylonitrile exposure in the US population and provide important biomonitoring data on acrylonitrile exposure.
Topics: Acrylonitrile; Biomarkers; Cotinine; Cysteine; Humans; Nutrition Surveys; Smoking; Tobacco Smoke Pollution; United States
PubMed: 33424026
DOI: 10.1038/s41370-020-00286-1 -
International Journal of Biological... Dec 2023The aim of this study was to develop a lightweight epoxy based biocomposite for morphing wing and unmanned aerial vehicle (UAV) applications. The proposed composite was...
Development of cashew nut shell lignin-acrylonitrile butadiene styrene 3D printed core and industrial hemp/aluminized glass fiber epoxy biocomposite for morphing wing and unmanned aerial vehicle applications.
The aim of this study was to develop a lightweight epoxy based biocomposite for morphing wing and unmanned aerial vehicle (UAV) applications. The proposed composite was developed using a 3D printed high stiffness lignin-Acrylonitrile Butadiene Styrene (ABS) core and industrial hemp with aluminized glass fiber epoxy skin. The ABS was reinforced using lignin macromolecule derived from cashew nut shells via twin screw extruder and the core was printed using an industrial grade 3D printer. Furthermore, the composites were prepared by compression moulding with an ABS-lignin core and hemp/aluminized GF surface and characterized according to respective American society of testing and materials (ASTM) standards. The findings indicate that the addition of 30 vol% Al-glass and hemp fiber with lignin strengthened ABS core improved the mechanical properties. The composite material designated as "E2" exhibits the maximum mechanical properties, providing tensile strength, flexural strength, Izod impact, interlaminar shear strength (ILSS), and compression values of, 136 MPa, 168 MPa, 4.82 kJ/m, 21 MPa, and 155 MPa respectively. The maximal energy absorbed by composite designation "E2," during drop load impact test is 20.6 J. Similarly, the composite designation "E2"gives fatigue life cycles of 33,709, 25,781 and 19,633 for 50 %, 70 % and 90 % of ultimate tensile strength (UTS) and 32.5 (K) MPa⋅m and 0.76 (G) MJ/m in fracture toughness and energy release rate respectively.
Topics: Animals; Butadienes; Acrylonitrile; Anacardium; Cannabis; Lignin; Nuts; Unmanned Aerial Devices; Epoxy Resins; Printing, Three-Dimensional; Styrenes
PubMed: 37758105
DOI: 10.1016/j.ijbiomac.2023.127068 -
Polymers Jul 2023Acrylonitrile butadiene styrene (ABS) is a thermoplastic polymer widely used in several everyday life applications; moreover, it is also one of the most employed...
Acrylonitrile butadiene styrene (ABS) is a thermoplastic polymer widely used in several everyday life applications; moreover, it is also one of the most employed plastics in contemporary artworks and design objects. In this study, the chemical and thermal properties of an ABS-based polymer and its photo-degradation process were investigated through a multi-analytical approach based on thermal, mass spectrometric and spectroscopic techniques. LEGO building blocks were selected for studying the ABS properties. First, the composition of unaged LEGO bricks was determined in terms of polymer composition and thermal stability; then, the bricks were subjected to UV-Vis photo-oxidative-accelerated ageing for evaluation of possible degradation processes. The modifications of the chemical and thermal properties were monitored in time by a multi-technique approach aimed at improving the current knowledge of ABS photodegradation, employing pyrolysis online with gas chromatography and evolved gas analysis, coupled with mass spectrometric detection (Py-GC-MS and EGA-MS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and corroborated by external reflection FT-IR spectroscopy. The multimodal approach provided new evidence on the two-step degradation pathway proposed for ABS, defining molecular markers for polybutadiene oxidation and styrene-acrylonitrile depolymerization. Moreover, the results highlighted the feasibility of correlating accurate compositional and thermal data acquired by bulk techniques with external reflection FT-IR spectroscopy as a non-invasive portable tool to monitor the state of conservation of plastic museum objects in-situ.
PubMed: 37571161
DOI: 10.3390/polym15153267