摘要 :
Synthetic plastic is used throughout daily life and industry, threatening organisms with microplastic pollution.
Polystyrene is a major plastic polymer and also widely found sources of plastic wastes and microplastics. Here,
we ...
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Synthetic plastic is used throughout daily life and industry, threatening organisms with microplastic pollution.
Polystyrene is a major plastic polymer and also widely found sources of plastic wastes and microplastics. Here,
we report that Enterobacter hormaechei LG3 (CP118279.1), a facultative anaerobic bacterial strain isolated from
the gut of Tenebrio molitor larvae (mealworms) can oxidize and depolymerize polystyrene under anaerobic
conditions. LG3 performed biodegradation while forming a biofilm on the plastic surface. PS biodegradation was
characterized by analyses of surface oxidation, change in morphology and molecular weights, and production of
biodegraded derivative. The biodegradation performance by LG3 was compared with PS biodegradation by
Bacillus amyloliquefaciens SCGB1 under both anaerobic and aerobic conditions. In addition, through nanopore
sequencing technology, we identified degradative enzymes, including thiol peroxidase (tpx), alkyl hydroperoxide
reductase C (ahpC) and bacterioferritin comigratory protein (bcp). Along with the upregulation of degradative
enzymes for biodegradation, changes in lipid A and biofilm-associated proteins were also observed after the cells
were incubated with polystyrene microplastics. Our results provide evidence for anaerobic biodegradation by
polystyrene-degrading bacteria and show alterations in gene expression patterns after polystyrene microplastics
treatment in the opportunistic pathogen Enterobacter hormaechei.
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Hydrophillic macronet resins were prepared via a route which includes simultaneous sulphonation and cross-linking of styrene-acrylonitrile copolymer and polystyrene foam. Chlorosulphonic acid was employed as both the sulphonating ...
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Hydrophillic macronet resins were prepared via a route which includes simultaneous sulphonation and cross-linking of styrene-acrylonitrile copolymer and polystyrene foam. Chlorosulphonic acid was employed as both the sulphonating reagent for the introduction of the sulphonic acid group on styrene units and the medium for the formation of sulphone-type cross-links. Controlled cross-linked structures were achieved by the parallel participation of acetic acid or acetic anhydride as sulphone cross-bridging regulators. The reaction yield, as well as the properties of the formed gels, were studied in respect to the cross-linking regulator concentration and the chlorosulphonic acid flow rate. Both strongly and weakly acidic ion-exchangers on the same substrate were achieved when styrene-acrylonitrile copolymer was used as a raw material. The synthesized macronet ion-exchangers were found to exhibit high swelling abilities and intermediate ion-exchange capacities while scanning electron microscopy (SEM) revealed their morphology. [References: 30]
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English French Background: Hyperkalemia is a potentially life-threatening electrolyte abnormality defined as a serum potassium above the lab reference range (usually >5.0-5.5 mEq/L). Polystyrene resins, including sodium polystyren...
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English French Background: Hyperkalemia is a potentially life-threatening electrolyte abnormality defined as a serum potassium above the lab reference range (usually >5.0-5.5 mEq/L). Polystyrene resins, including sodium polystyrene sulfonate (SPS) and calcium polystyrene sulfonate (CPS), have long been used to treat hyperkalemia. Sodium polystyrene sulfonate/calcium polystyrene sulfonate act by exchanging a cation for potassium within the intestinal lumen. While SPS and CPS have been available since the 1960s, there are rising concerns about the validity of the data supporting its use and about serious adverse gastrointestinal effects. Objective: The objective of this systematic review was to quantify the efficacy and safety of polystyrene sulfonate resins (SPS/CPS) in the treatment of adults with hyperkalemia. This review focuses on the randomized control trial (RCT), interventional non-RCT, and observational data available on SPS/CPS use. Design: Systematic review. Setting: Any country of origin. Both inpatient and outpatient settings. Patients: Adults with hyperkalemia treated with polystyrene sulfonate resins. Measurements: The primary outcome was change in serum potassium. The secondary outcomes included adverse effects of SPS/CPS and prevention of recurrent hyperkalemia. Methods: We conducted a systematic review using Cochrane Library, EMBASE (1947-2019), and Medline (1946-2019) databases. Literature reviews, systematic reviews, case studies, case series, and editorial pieces were excluded. Included studies were assessed for risk of bias. Results: Four RCTs, 21 observational studies, and 5 quasi-experimental trials were included. A total of 212?351 patients were included. Two thousand and fifty-eight patients were studied for the primary outcome and 210?293 patients were studied for the secondary outcomes. Study designs were heterogeneous and not amenable to meta-analysis. Most studies included nonhemodialysis outpatients older than 65 years. Of the included studies, 22/25 (88%) demonstrated a reduction of serum potassium >0.5 mEq/L over the study period. The magnitude of reduction in serum potassium of potassium resin compared with placebo or matched controls in the 3 low-risk studies identified was 0.14 to 1.04 mEq/L. However, each study used different dosing regimens. Ten of 22 studies reported the effects of polystyrene resins on serum potassium within 24 hours. A few high-quality observational studies suggest an increased risk of serious adverse gastrointestinal events with a relative risk of 2.10 and a hazard ratio of 1.25 to 1.94; however, the absolute risk remains low. The incidence of adverse gastrointestinal events is 16 to 23 events per 1000 person-years. Limitations: We acknowledge several limitations in this study. Case studies and case series were excluded from the search results. Large case series may have been excluded despite having comparable sample sizes to studies included due to lack of a comparator and calculated estimates. Due to the heterogeneity of the studies, the data were unable to be meta-analyzed and as such the potassium-lowering effect of polystyrene sulfonate resins remains founded on small studies with potential confounders. Conclusions: This systematic review demonstrates a continued lack of high-quality evidence for the use of SPS/CPS in hyperkalemia. Studies investigated highly variable timelines and the most robust evidence for SPS/CPS use is in chronic hyperkalemia. While the absence of high-quality evidence does not exclude the possibility of benefit, prescribers must understand that the use of SPS/CPS in acute hyperkalemia is not supported by high-quality evidence. Trial registration: The protocol for this systematic review was not registered. Abrégé Contexte: L’hyperkaliémie est un déséquilibre électrolytique potentiellement mortel qui se définit par une concentration sérique en potassium supérieure aux valeurs de référence (généralement supérieure à 5,0-5,5?mEq/L). Les résines polystyréniques, le sulfonate de polystyrène sodique (SPS) et le sulfonate de polystyrène calcique (SPC), sont depuis longtemps utilisées pour traiter l’hyperkaliémie. Le SPS et le SPC agissent dans la lumière intestinale en échangeant un cation contre du potassium. Bien que ces résines soient disponibles depuis les années 1960, la validité des données justifiant leur utilisation et le risque d’effets indésirables graves qu’elles posent pour le système gastro-intestinal suscitent de plus en plus d’inquiétudes. Objectif: Cette revue systématique visait à quantifier l’efficacité et l’innocuité des résines SPS/SPC dans le traitement de l’hyperkaliémie chez les adultes. Cette revue se concentre sur les données issues d’essais contr?lés randomisés, d’études interventionnelles non randomisées et d’études observationnelles portant sur cette utilisation. Type d’étude: Revue systématique Cadre: Les études étaient incluses peu importe le pays d’origine. Patients traités en ambulatoire ou e
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High-quality graphene zinc-containing anticorrosive coatings are highly and urgently desirable for effective, economical anticorrosion of metals and alloys in industrial products. The realization of such coatings is, however, hind...
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High-quality graphene zinc-containing anticorrosive coatings are highly and urgently desirable for effective, economical anticorrosion of metals and alloys in industrial products. The realization of such coatings is, however, hindered by the dispersibility and compatibility of the graphene in them. This work reports a novel direct modification of graphene using sodium polystyrene sulfonate (PSS) without reduction of graphene oxide, leading to homogeneous dispersion of graphene in water. The agglomeration of graphene is prevented thanks to the formation of π?π interaction between PSS and graphene sheets. Such graphene dispersion can effectively improve the anticorrosion performance of the zinc-containing epoxy coatings. With the addition of graphene modified by PSS into the 20% zinc-containing epoxy coating (graphene is 0.05% by weight of the coating), its anticorrosion properties revealed by both electrochemical characterization and the neutral salt spray tolerance analysis are rather close to those of 60% zinc-containing epoxy coating. These results demonstrate that direct PSS modification is an effective method for graphene dispersion and thus open a pathway to achieve graphene zinc-containing anticorrosive coatings with high performance.
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A styrene solution of waste expanded polystyrene (EPS) Is prepared by dissolving EPS in styrene at an EPS concentration of 40 percent. The polystyrene mortars using waste EPS solution-based binders are prepared with various conten...
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A styrene solution of waste expanded polystyrene (EPS) Is prepared by dissolving EPS in styrene at an EPS concentration of 40 percent. The polystyrene mortars using waste EPS solution-based binders are prepared with various contents of crosslinking agent, and tested for working life, setting shrinkage, flexural and compressive strengths, and hot water resistance As a result, the working life of the polystyrene mortars is shortened, and their setting shrinkage is increased with increasing content of crosslinking agent. Their flexural strength decreases while their compressive strength increases with an increase in the content of crosslinking agent. In addition, the polystyrene mortars have excellent hot water resistance.
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Polystyrene latex particles were swollen with aniline and subsequently exposed to ammonium peroxydisulfate solution. The polyaniline membrane was produced at the particle interface and separated both reactants. The electrons from ...
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Polystyrene latex particles were swollen with aniline and subsequently exposed to ammonium peroxydisulfate solution. The polyaniline membrane was produced at the particle interface and separated both reactants. The electrons from aniline monomer are transferred to oxidant molecules through conducting polyaniline membrane. The aniline and peroxydisulfate thus react without the need to physically meet.Polyaniline gradually penetrated inside latex particle, in contrast to core–shell morphology obtained in classical coating of latex particles with polyaniline.
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Polystyrene-substituted [70]fullerene was synthesized via the reaction of C_70 with living polystyrene anions in the THF-C_6H_6 mixed solvents. The covalent graftings of the polystyrene arms onto the c_70 core result in the enhanc...
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Polystyrene-substituted [70]fullerene was synthesized via the reaction of C_70 with living polystyrene anions in the THF-C_6H_6 mixed solvents. The covalent graftings of the polystyrene arms onto the c_70 core result in the enhancement of the absorption degree at longer wavelengths, and in the decrease of the thermal stability and the glass transition temperature of the parent polymer. The other characterization results are also described.
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Narrow distribution macrocyclic poly(9,9-dimethyl-2-vinylfluorene) (PDMVF) and the matching linear precursors with the same degree of polymerization (DPn from 12 to 145) were synthesized via anionic polymerization followed by the ...
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Narrow distribution macrocyclic poly(9,9-dimethyl-2-vinylfluorene) (PDMVF) and the matching linear precursors with the same degree of polymerization (DPn from 12 to 145) were synthesized via anionic polymerization followed by the end-to-end coupling with 1,4-bis(bromomethyl)benzene (DBX) or 9,10-bis(chloromethyl)anthracene (BCMA). The molecular characterization was carried out by size exclusion chromatography (SEC), proton NMR, and ALUM. The ratios of apparent molecular weights (MW's) of the macrocycles and those of the matching linear polymers decreased with increasing molecular weights as seen with other vinylaromatic macrocycles. However, in contrast to all other vinylaromatic macrocycles, the PDMVF macrocycles showed increases in glass transition temperature with decreasing MW. [References: 46]
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This paper presents the ideation of a force feedback temperature control system for advanced hot-tool plastic foam cutting systems. With respect to other controllers, the force feedback temperature control strategy is simple to ap...
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This paper presents the ideation of a force feedback temperature control system for advanced hot-tool plastic foam cutting systems. With respect to other controllers, the force feedback temperature control strategy is simple to apply given that it modulates the electrical power input independent of the predetermined tool path and feed rate. The control strategy is implemented by making a series of one-dimensional cuts with a hot wire. The electrical power input to the hot wire is modulated to provide constant tool temperature. Since the cutting force and kerf width are both dependent on the tool temperature, maintaining a constant tool temperature results in consistent cut surface characteristics. The force feedback temperature control theory and its practical implementation in one dimension are presented as well as an accurate description of the cutting process. Experimental results are presented to validate both theoretical assumptions and practical benefits. A number of barriers to implementation for three-dimensional sculpting are discussed with possible solutions. The experimental results validate the predictions that force feedback temperature control is an effective control method for hot-tool plastic foam cutting.
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摘要 :
This paper presents the ideation of a force feedback temperature control system for advanced hot-tool plastic foam cutting systems. With respect to other controllers, the force feedback temperature control strategy is simple to ap...
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This paper presents the ideation of a force feedback temperature control system for advanced hot-tool plastic foam cutting systems. With respect to other controllers, the force feedback temperature control strategy is simple to apply given that it modulates the electrical power input independent of the predetermined tool path and feed rate. The control strategy is implemented by making a series of one-dimensional cuts with a hot wire. The electrical power input to the hot wire is modulated to provide constant tool temperature. Since the cutting force and kerf width are both dependent on the tool temperature, maintaining a constant tool temperature results in consistent cut surface characteristics. The force feedback temperature control theory and its practical implementation in one dimension are presented as well as an accurate description of the cutting process. Experimental results are presented to validate both theoretical assumptions and practical benefits. A number of barriers to implementation for three-dimensional sculpting are discussed with possible solutions. The experimental results validate the predictions that force feedback temperature control is an effective control method for hot-tool plastic foam cutting.
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