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Journal of Environmental Management Dec 2023Environmental concerns associated with the rapid rising plastic consumption have led to the search for better waste utilization and management. Pyrolysis has emerged as...
Environmental concerns associated with the rapid rising plastic consumption have led to the search for better waste utilization and management. Pyrolysis has emerged as an ideal and promising technique for energy extraction from plastic waste. The aim of this work is to explore the waste plastic pyrolysis behavior under non-isothermal heating conditions. The decomposition characteristics, reaction mechanism, kinetics and thermodynamics of a typical widely used thermosetting plastic, acrylonitrile butadiene styrene (ABS), were studied via coupled thermogravimetry, Fourier transform infrared spectrometry and gas chromatography-mass spectrometry analysis (TG-FTIR-GC/MS). Kinetic analysis showed the average E values are estimated to be 187.02, 188.55, 187.04 and 185.67 kJ/mol via advanced Vyazovkin, Flynn-Wall-Ozawa (FWO), Tang and Starink model-free method, respectively. Model-fitting CR and master-plots method indicated that f(α)=(1-α) is the most probable reaction mechanism. The equation of kinetic compensation effect was further developed as lnA = -3.1955 + 0.1736 E. Based on these initial inferences, a new reaction scheme coupled with Particle Swarm Optimization (PSO) was put forward for modeling ABS pyrolysis. The optimized values of E, A and n are 198.07 kJ/mol, 7.61 × 10 s and 1.56, respectively. The predicted results showed that the experimental data can be well characterized by the optimized parameters from PSO, validating the effectiveness and accuracy of the inverse modeling procedure. Moreover, it is found that the volatile products are mainly composed of aromatic compounds, ketones, amines, esters, nitrile compounds, alkenes and amines. Based on the FT-IR and GC-MS results, the possible chemical reactions for ABS pyrolysis from molecular structure were proposed. Finally, thermodynamic analysis was carried out, the calculated values of enthalpy ΔH, Gibb's free energy ΔG and entropy ΔS indicated that non-spontaneous reactions with low favorability exists during ABS decomposition, the process is complex therefore extra energy is needed to promote the reaction. The obtained results should offer as an important reference for future disposal and thermochemical management of such polymer waste.
Topics: Acrylonitrile; Kinetics; Spectroscopy, Fourier Transform Infrared; Butadienes; Styrene; Thermogravimetry; Amines
PubMed: 37827086
DOI: 10.1016/j.jenvman.2023.119080 -
Environmental Science. Processes &... Dec 2023The timespans over which different plastics degrade in the environment are poorly understood. This study aimed to rank the degradation speed of five widespread plastic...
The timespans over which different plastics degrade in the environment are poorly understood. This study aimed to rank the degradation speed of five widespread plastic polymers-low density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), polylactic acid (PLA) and polyethylene terephthalate (PET)-in terms of their physicochemical properties. Five of the six samples were plastic films with identical dimensions, which allowed the influence of morphology to be excluded, with a polyethylene carrier bag (PEB) tested for comparison. An accelerated weathering chamber was used to photochemically degrade samples over 41 days, with degradation monitored mass loss and changes to carbonyl index, crystallinity and contact angle. The mass loss ranking was PP ≫ LDPE > PEB > PS > PLA > PET. Estimates of the time needed for complete degradation ranged from 0.27 years for PP to 1179 years for PET. Therefore, mass loss in PP proceeded more rapidly than the other polymers, which was unexpected based on previous literature and is plausibly explained by the presence of an unlisted additive which accelerated degradation. Increases in carbonyl index proceeded more rapidly in PP and LDPE than the other polymers tested. However, changes in contact angle and crystallinity did not correspond to the mass loss ranking. Therefore, monitoring the carbonyl index during accelerated weathering trials can indicate which polymers will fragment more quickly. However, alternative approaches are needed to simulate conditions where photooxidation reactions are negligible, such as the ocean floor.
Topics: Plastics; Polyethylene; Polymers; Polystyrenes; Polypropylenes; Polyesters
PubMed: 37882078
DOI: 10.1039/d3em00295k -
Advances in Therapy Apr 2024Supplementation with dietary neuro-pigments lutein (L) and zeaxanthin (Z) has been shown to improve many aspects of visual and cognitive function in adults. In this... (Randomized Controlled Trial)
Randomized Controlled Trial
INTRODUCTION
Supplementation with dietary neuro-pigments lutein (L) and zeaxanthin (Z) has been shown to improve many aspects of visual and cognitive function in adults. In this study, we tested whether a similar intervention could improve such outcomes in preadolescent children.
METHODS
Sixty children (age range 5-12 years) were randomized in a 2:1 ratio in this double-blind, placebo-controlled clinical trial. Subjects were supplemented with gummies containing either a combination of 10 mg lutein and 2 mg zeaxanthin (LZ) or placebo for 180 days. Macular pigment optical density (MPOD) was the primary endpoint. The secondary endpoints included serum levels of L and Z, and brain-derived neurotrophic factor (BDNF), critical flicker fusion (CFF), eye strain and fatigue using visual analogue scales (VAS), Children's Sleep Habits Questionnaire-Abbreviated (CSHQ-A), and Creyos Health cognitive domains like attention, focus/concentration, episodic memory and learning, visuospatial working memory, and visuospatial processing speed. Safety was assessed throughout the study on the basis of physical examination, vital signs, clinical laboratory tests, and monitoring of adverse events.
RESULTS
The LZ group showed significant increases in MPOD at all visits post-supplementation, with significant increases as early as day 42 compared to placebo. The LZ group showed significant increases in serum lutein levels, reduced eye strain and fatigue, and improved cognitive performance (focus, episodic memory and learning, visuospatial working memory) at days 90 and 180 compared to placebo. Further, the LZ group showed significant increases in processing speed (CFF), attention, visuospatial processing, and serum Z and BDNF levels on day 180 compared to placebo. No safety concerns were observed.
CONCLUSIONS
Supplementing LZ resulted in increased MPOD levels, along with increased serum levels of L, Z, and BDNF. These changes were associated with improved visual and cognitive performances and reduction in eye strain and eye fatigue in the children receiving LZ gummies. The investigational product was safe and well tolerated.
TRIAL REGISTRATION
http://ctri.nic.in/ Identifier CTRI/2022/05/042364.
Topics: Adult; Child; Humans; Child, Preschool; Lutein; Zeaxanthins; Brain-Derived Neurotrophic Factor; Dietary Supplements; Macular Pigment; Cognition; Double-Blind Method
PubMed: 38363462
DOI: 10.1007/s12325-024-02785-1 -
Environmental Science & Technology Sep 2023Recent studies have shown that instantaneous gas-particle equilibrium partitioning assumptions fail to predict SOA formation, even at high relative humidity (∼85%),...
Recent studies have shown that instantaneous gas-particle equilibrium partitioning assumptions fail to predict SOA formation, even at high relative humidity (∼85%), and photochemical aging seems to be one driving factor. In this study, we probe the minimum aging time scale required to observe nonequilibrium partitioning of semivolatile organic compounds (SVOCs) between the gas and aerosol phase at ∼50% RH. Seed isoprene SOA is generated by photo-oxidation in the presence of effloresced ammonium sulfate seeds at <1 ppbv NO, aged photochemically or in the dark for 0.3-6 h, and subsequently exposed to fresh isoprene SVOCs. Our results show that the equilibrium partitioning assumption is accurate for fresh isoprene SOA but breaks down after isoprene SOA has been aged for as short as 20 min even in the dark. Modeling results show that a semisolid SOA phase state is necessary to reproduce the observed particle size distribution evolution. The observed nonequilibrium partitioning behavior and inferred semisolid phase state are corroborated by offline mass spectrometric analysis on the bulk aerosol particles showing the formation of organosulfates and oligomers. The unexpected short time scale for the phase transition within isoprene SOA has important implications for the growth of atmospheric ultrafine particles to climate-relevant sizes.
Topics: Hemiterpenes; Particulate Matter; Butadienes; Organic Chemicals; Aerosols; Air Pollutants
PubMed: 37708377
DOI: 10.1021/acs.est.3c03532 -
American Journal of Men's Health 2023Lutein, zeaxanthin, and β-cryptoxanthin are polar oxygenated carotenoids found to be detectable in more than 95% of the population in the United States. Research has...
Lutein, zeaxanthin, and β-cryptoxanthin are polar oxygenated carotenoids found to be detectable in more than 95% of the population in the United States. Research has linked these carotenoids with lower coronary heart disease prevalence. This study investigates the association of serum lutein/zeaxanthin and β-cryptoxanthin with erectile dysfunction (ED) among middle-aged and older men in the United States. Serum lutein/zeaxanthin and β-cryptoxanthin were independent variables. The outcome variable was ED. Analyzed data from 1,302 men (≥40 years old) who participated in the National Health and Nutrition Examination Survey 2001-2002 cross-sectional study were included. After adjusting for all covariates, serum lutein/zeaxanthin negatively correlated with ED (odds ratio [OR]: 0.972, 95% confidence interval [CI]: [0.951, 0.994], = .011). However, a U-shaped association between serum lutein/zeaxanthin and ED was detected in men with diabetes or prevalent cardiovascular disease. A U-shaped non-linear association was observed between β-cryptoxanthin levels and ED. These findings suggest that while both lutein/zeaxanthin and β-cryptoxanthin are recognized as essential antioxidants, maintaining lower serum lutein/zeaxanthin levels and appropriate serum β-cryptoxanthin levels may offer potential benefits for individuals with ED. Further investigations, particularly prospective studies, are warranted to determine the role of serum lutein/zeaxanthin and β-cryptoxanthin in the biological mechanism associated with ED.
Topics: Middle Aged; Male; Humans; United States; Aged; Adult; Lutein; Zeaxanthins; Erectile Dysfunction; Beta-Cryptoxanthin; Nutrition Surveys; Cross-Sectional Studies; Prospective Studies; Carotenoids
PubMed: 38102781
DOI: 10.1177/15579883231216905 -
Critical Reviews in Food Science and... 2024Carotenoids are natural pigments that provide many health benefits to living organisms. Although terrestrial plants are the major dietary source of carotenoids for... (Review)
Review
Carotenoids are natural pigments that provide many health benefits to living organisms. Although terrestrial plants are the major dietary source of carotenoids for humans, aquatic animals (especially fish and shellfish) are equally important because they are rich in certain important carotenoids lacking in fruits and vegetables. Although extensive research has focused on exploring the carotenoid content and composition in fish and shellfish, this information is poorly organized. This paper reviews the scientific evidence for the carotenoid content and composition in fish and shellfish. It makes serious attempts to summarize the relevant data published on specific research questions in order to improve the understanding of various evidence to clarify the research status of carotenoids in fish and shellfish and defining topics for future studies. From the analysis of published data, it is obvious that most fish and shellfish are rich in complex carotenoids (e.g. astaxanthin, fucoxanthin, fucoxanthinol, lutein). These carotenoids have stronger antioxidant effect, higher efficiency in removing the singlet oxygen and the peroxyl radicals, and have a variety of health benefits. Carotenoid levels in fish and shellfish depend on genotype, climatic conditions of the production area, storage and cooking methods. However, the information of the bioavailability of fish/shellfish carotenoids to human is very limited, which hinders the actual contributions to health. The findings of this study can be used as a guide to select appropriate fish and shellfish as dietary sources of carotenoids, and provide information about potential fish and shellfish species for aquaculture to produce carotenoids to meet part of the growing demand for natural carotenoids.
Topics: Animals; Humans; Carotenoids; Antioxidants; Shellfish; Lutein; Diet; Fishes
PubMed: 35930379
DOI: 10.1080/10408398.2022.2106937 -
Food Chemistry Jun 2024Given their multifaceted roles, carotenoids have garnered significant scientific interest, resulting in a comprehensive and intricate body of literature that... (Review)
Review
Given their multifaceted roles, carotenoids have garnered significant scientific interest, resulting in a comprehensive and intricate body of literature that occasionally presents conflicting findings concerning the proper characterization, quantification, and bioavailability of these compounds. Nevertheless, it is undeniable that the pursuit of novel carotenoids remains a crucial endeavor, as their diverse properties, functionalities and potential health benefits make them invaluable natural resources in agri-food and health promotion through the diet. In this framework, particular attention is given to ketocarotenoids, viz., astaxanthin (one of them) stands out for its possible multifunctional role as an antioxidant, anticancer, and antimicrobial agent. It has been widely explored in the market and utilized in different applications such as nutraceuticals, food additives, among others. Adonirubin and adonixanthin can be naturally found in plants and microorganisms. Due to the increasing significance of natural-based products and the remarkable opportunity to introduce these ketocarotenoids to the market, this review aims to provide an expert overview of the pros and cons associated with adonirubin and adonixanthin.
Topics: Carotenoids; Canthaxanthin; Antioxidants
PubMed: 38301562
DOI: 10.1016/j.foodchem.2024.138610 -
Bioresource Technology Jan 2024Diatoms, with their complex cellular architecture, have been recognized as a source of limitless potential. These microbes are common in freshwater and marine habitats... (Review)
Review
Diatoms, with their complex cellular architecture, have been recognized as a source of limitless potential. These microbes are common in freshwater and marine habitats and are essential for primary production and carbon sequestration. They are excellent at utilizing nutrients, providing a sustainable method of treating wastewater while also producing biomass rich in beneficial substances like vitamins, carotenoids, polysaccharides, lipids, omega-3 fatty acids, pigments, and novel bioactive molecules. Additionally, they are highly efficient organisms that can be employed to monitor the environment by acting as trustworthy indicators of water quality. This comprehensive review explores the multifaceted applications of diatoms in a variety of fields, such as bioremediation, aquaculture, value-added products, and other applications. The review set out on a path towards greener, more sustainable methods amicable to both industry and the environment by utilizing theenormous diverse biotechnological potentials of diatoms.
Topics: Diatoms; Biotechnology; Carotenoids; Polysaccharides; Biomass
PubMed: 37923226
DOI: 10.1016/j.biortech.2023.129905 -
Nutrition Research Reviews Dec 2023Many epidemiological studies have emphasised the relation between carotenoid dietary intake and their circulating concentrations and beneficial health effects, such as... (Review)
Review
Many epidemiological studies have emphasised the relation between carotenoid dietary intake and their circulating concentrations and beneficial health effects, such as lower risk of cardiometabolic diseases and cancer. However, there is dispute as to whether the attributed health benefits are due to native carotenoids or whether they are instead induced by their metabolites. Several categories of metabolites have been reported, most notably involving (a) modifications at the cyclohexenyl ring or the polyene chain, such as epoxides and geometric isomers, (b) excentric cleavage metabolites with alcohol-, aldehyde- or carboxylic acid-functional groups or (c) centric cleaved metabolites with additional hydroxyl, aldehyde or carboxyl functionalities, not counting their potential phase-II glucuronidated / sulphated derivatives. Of special interest are the apo-carotenoids, which originate in the intestine and other tissues from carotenoid cleavage by β-carotene oxygenases 1/2 in a symmetrical / non-symmetrical fashion. These are more water soluble and more electrophilic and, therefore, putative candidates for interactions with transcription factors such as NF-kB and Nrf2, as well as ligands for RAR-RXR nuclear receptor interactions. In this review, we discuss detected apo-carotenoids, their reported tissue concentrations, and potential associated health effects, focusing exclusively on the human situation and based on quantified / semi-quantified carotenoid metabolites proven to be present in humans.
Topics: Humans; Retinoids; Carotenoids; Neoplasms; Aldehydes
PubMed: 36380523
DOI: 10.1017/S095442242200021X -
Naunyn-Schmiedeberg's Archives of... Mar 2024With cancer being a leading cause of death globally, there is an urgent need to improve therapeutic strategies and identify effective chemotherapeutics. This study aims... (Review)
Review
With cancer being a leading cause of death globally, there is an urgent need to improve therapeutic strategies and identify effective chemotherapeutics. This study aims to highlight the potential of crocetin, a natural product derived from certain plants, as an anticancer agent. It was conducted an extensive review of the existing literature to gather and analyze the most recent data on the chemical properties of crocetin and its observed effects in various in vitro and in vivo studies. The study particularly focused on studies that examined crocetin's impact on cell cycle dynamics, apoptosis, caspases and antioxidant enzyme levels, tumor angiogenesis, inflammation, and overall tumor growth. Crocetin exhibited diverse anti-tumorigenic activities including inhibition of tumor cell proliferation, apoptosis induction, angiogenesis suppression, and potentiation of chemotherapy. Multiple cellular and molecular pathways such as the PI3K/Akt, MAPK and NF-κB were modulated by it. Crocetin demonstrates promising anti-cancer properties and offers potential as an adjunctive or alternative therapy in oncology. More large-scale, rigorously designed clinical trials are needed to establish therapeutic protocols and ascertain the comprehensive benefits and safety profile of crocetin in diverse cancer types.
Topics: Humans; Phosphatidylinositol 3-Kinases; Vitamin A; Carotenoids; Antioxidants; Neoplasms; Apoptosis
PubMed: 37736836
DOI: 10.1007/s00210-023-02714-z