Coupling dechlorination and catalytic pyrolysis to produce carbon nanotubes from mixed polyvinyl chloride and polyethylene

The presence of chlorine in polyvinyl chloride (PVC) presents a major challenge for realizing the high-value utilization of real waste plastics. The objective of this research was to develop a chlorine-resistant process for the preparation of carbon nanotubes (CNTs) from mixed plastics containing PVC. This study investigates the influence of PVC content and various dechlorinating agents (CaO, Na2CO3, red mud (RM), ZSM-5, Fe-Al2O3, Fe(OH)3) on CNTs formation. The results showed that PVC content exceeding 5 % significantly inhibits CNTs formation. Employing dechlorinating agents in the pyrolysis process results in a substantial yield of CNTs from mixed plastics containing 10 % PVC. Among the dechlorinating agents, RM proves to be the most effective, leading to the highest carbon yield (at 30 wt%) and superior CNTs quality. Other dechlorinating agents, except for ZSM-5, yield comparable results, although there were some obvious variations of volatiles. Further investigation of the role of dechlorinating agents from the perspective of volatiles evolution was conducted via Py-GC/MS, and found that the dechlorination agent efficiently absorbs the HCl from mixed plastics pyrolysis, while also exhibiting catalytic and regulatory influence on volatile components. These findings offer valuable insights for the development of a chlorine-resistant process in the preparation of CNTs from mixed plastics that contain PVC.

Molecular modeling of the carbohydrate corona formation on a polyvinyl chloride nanoparticle and its impact on the adhesion to lipid bilayers

The pervasive presence of nanoplastics (NPs) in the environment has gained increasing attention due to their accumulation in living organisms. These emerging contaminants inevitably interact with extracellular polymeric substances along respiratory or gastrointestinal tracts, and diverse organic coating on the surface of NPs, known as bio- or eco-corona, is formed. Although its impact on altering the NP properties and potential cell internalization has been extensively examined, studies on its role in NP partitioning in the cell membrane are elusive yet. In this work, molecular dynamics is used to investigate the formation of chitosan (CT) corona centered on a polyvinyl chloride (PVC) nanoparticle and the uptake of the resulting complex onto lipid membranes. Coarse-grained models compatible with the newly developed Martini 3.0 force field are implemented for the two polymers employing the atomistic properties as targets in the parameterization. The reliability of the coarse-grained polymer models is demonstrated by reproducing the structural properties of the PVC melt and of solvated CT strands, as well as by determining the conformation adopted by the latter at the NP surface. Results show that the spontaneous binding of CT chains of high and intermediate protonation degrees led to the formation of soft and hard corona that modulates the interaction of PVC core with model membranes. The structural changes of the corona adsorbed at the lipid-water interface enable a subsequent transfer of the NP to the center of the saturated lipid membranes and a complete or partial transition to a snorkel conformation depending on the hydrophilic/hydrophobic balance in the CT-PVC complex. Overall, the computational investigation of the coarse-grained model system provides implications for understanding how the eco-corona development influences the uptake and implicit toxicology of NPs.

Postpolymerization Modification of Poly(2-vinyl-4,4-dimethyl azlactone) as a Versatile Strategy for Drug Conjugation and Stimuli-Responsive Release

Postpolymerization modification of highly defined "scaffold" polymers is a promising approach for overcoming the existing limitations of controlled radical polymerization such as batch-to-batch inconsistencies, accessibility to different monomers, and compatibility with harsh synthesis conditions. Using multiple physicochemical characterization techniques, we demonstrate that poly(2-vinyl-4,4-dimethyl azlactone) (PVDMA) scaffolds can be efficiently modified with a coumarin derivative, doxorubicin, and camptothecin small molecule drugs. Subsequently, we show that coumarin-modified PVDMA has a high cellular biocompatibility and that coumarin derivatives are liberated from the polymer in the intracellular environment for cytosolic accumulation. In addition, we report the pharmacokinetics, biodistribution, and antitumor efficacy of a PVDMA-based polymer for the first time, demonstrating unique accumulation patterns based on the administration route (i.e., intravenous vs oral), efficient tumor uptake, and tumor growth inhibition in 4T1 orthotopic triple negative breast cancer (TNBC) xenografts. This work establishes the utility of PVDMA as a versatile chemical platform for producing polymer-drug conjugates with a tunable, stimuli-responsive delivery.

Polyvinyl chloride solvent cement poisoning: a case report

BACKGROUND

S-lon® (S) is a locally produced polyvinyl chloride-based solvent cement. It is a clear, slightly viscous liquid. Other constituents include 1-cyclohexanone, 3-butanone, and 1-acetone. It is used ubiquitously for building construction in Sri Lanka. Although the clinical effects of the compound have not yet been ascertained, the constituents have been implicated in neurotoxicity, respiratory tract, eye and skin irritation, and delayed liver and renal injury.

CASE DESCRIPTION

A 42-year-old South Asian male presented following self-ingestion of S. His vital parameters were stable and initially managed symptomatically. A few hours later, he developed central nervous system depression and stridor requiring elective intubation. Examination of the upper airway revealed inflammation and edema. He was sedated and ventilated, and intravenous dexamethasone was administered. Attempts at removal of the nasogastric tube after extubation on day 3 failed. The patient had to be reintubated and sedated owing to extreme agitation not responding to routine doses of sedatives. The nasogastric tube had been amalgamated after reacting with S, forming a solid clump, later found after removal. The posterior pharynx and nasopharynx were packed and later removed before extubation. The patient made a full recovery and was transferred to the ward on day 5.

CONCLUSION

Ingestion of a sufficient quantity of S could result in gut absorption with central nervous system depression, coma, and even death. No antidote is available for toxicity, and management is largely supportive. As witnessed in our patient, chemical laryngitis and upper airway inflammation may lead to upper airway obstruction. Chemical reactions with medical equipment may lead to unforeseen outcomes.

Strong and tough poly(vinyl alcohol)/xanthan gum-based ionic conducting hydrogel enabled through the synergistic effect of ion cross-linking and salting out

The mechanical properties of ionic conductive hydrogels (ICHs) are generally inadequate, leading to their susceptibility to breakage under external forces and consequently resulting in the failure of flexible electronic devices. In this work, a simple and convenient strategy was proposed based on the synergistic effect of ion cross-linking and salting out, in which the hydrogels consisting of polyvinyl alcohol (PVA) and xanthan gum (XG) were immersed in zinc sulfate (ZnSO4) solution to obtain ICHs with exceptional mechanical properties. The salt-out effects between PVA chains and SO42- ions along with the cross-linked network of XG chains and Zn2+ ions contribute to the desirable mechanical properties of ICHs. Notably, the mechanical properties of ICHs can be adjusted by changing the concentration of ZnSO4 solution. Consequently, the optimum fracture stress and the fracture energy can reach 3.38 MPa and 12.13 KJ m-2, respectively. Moreover, the ICHs demonstrated a favorable sensitivity (up to 2.05) when utilized as a strain sensor, exhibiting an accurate detection of human body movements across various amplitudes.

Quantitative analysis of microplastics and nanoplastics released from disposable PVC infusion tubes

The exposure of micro- and nanoplastics (MNPs) via medical device is still unknown to us. Herein, a visual quantitative detection of polyvinyl chloride (PVC) MPs and a fluorescent quantitative detection of PVC NPs were developed. To overcome the aggregation of PVC NPs, sodium dodecylbenzene sulfonate was used as the stabilizer of PVC NPs. The brand-new disposable PVC infusion tubes were found to carry PVC MPs with the average total number (ATN) of 931.4 particles and PVC NPs with the average mass of 0.040 μg, respectively. For four typical infusion fluids such as 0.9% sodium chloride, 5% glucose, 5% sodium bicarbonate, hydroxyethyl starch 40 sodium chloride, the released PVC MPs and NPs were ranged from 1003.6 ∼ 3494.6 particles and 0.042 ∼ 0.087 μg, respectively in stimulating normal infusion scenario (room temperature 4 h). The released PVC MPs and NPs were also increased with the infusion duration and temperature. The released PVC MPs are mainly in granular form, accounting for 38 ∼ 49% of the total PVC MPs. Our findings indicate PVC MNPs can enter the blood vessel directly with the infusion fluids during intravenous infusion and the PVC MNPs exposure risk towards patients deserves more attention.

Wheat (Triticum aestivum L.) seedlings performance mainly affected by soil nitrate nitrogen under the stress of polyvinyl chloride microplastics

Microplastics are exotic pollutants and are increasingly detected in soil, but it remains poorly understood how microplastics impact soil and plant systematically. The present study was conducted to evaluate the effects of polyvinyl chloride microplastics (PVC-MPs) on wheat seedlings performance and soil properties. Under the stress of PVC-MPs, no new substance and functional groups were generated in soil by X-ray diffraction and the fourier transform infrared spectroscopy analyses, whereas the diffraction and characteristic peaks and of soil was affected by PVC-MPs. Wheat seedlings shoot biomass and soil nitrate nitrogen were significantly inhibited by PVC-MPs. Chlorophylls were not significant affected by PVC-MPs. Superoxide dismutase, catalase, and peroxidase activities in wheat seedlings increased, while malondialdehyde and proline contents decreased significantly. Redundancy analysis displayed that wheat seedlings traits can be largely explained by soil nitrate nitrogen. Our results indicate that PVC-MPs have more significant influence on soil structure than on soil substance composition. Moreover, even though antioxidant enzyme activities were improved to respond the stress of PVC-MPs, wheat seedlings are not severely impacted by PVC-MPs. Besides, soil nitrate nitrogen is the main factor on wheat seedlings performance and wheat seedlings are prone to ensure the root growth under the stress of PVC-MPs.

Microplastics as potential barriers to ultraviolet light emitting diode inactivation of MS2 bacteriophage: Influence of water-quality parameters

Microplastics have emerged as a concerning contaminant in drinking water sources, potentially interacting with pathogenic microorganisms and affecting the disinfection processes. In this study, MS2 was selected as an alternative for the human enteric virus. The influence of microplastics polyvinylchloride (MPs-PVC) on ultraviolet light emitting diode (UV-LED) inactivation of MS2 was investigated under various water chemistry conditions, such as MPs-PVC concentration, pH, salinity, and humic acid concentration. The results revealed that higher concentrations of MPs-PVC led to the reduced inactivation of MS2 by decreased UV transmittance, hindering the disinfection process. Additionally, the inactivation efficiency of MS2 in the presence of MPs-PVC was influenced by pH, and acidic solution (pH at 4, 5, and 6) exhibited higher efficiency compared to alkaline solution (pH at 8 and 9) and neutral solution (pH at 7). The low Na+ concentrations (0-50 mM) had a noticeable effect on MS2 inaction efficiency in the presence of MPs-PVC, while the addition of Ca2+ posed an insignificant effect due to the preferential interaction with MPs-PVC. Furthermore, the inactivation rate of MS2 initially increased and then decreased with increasing the concentration of humic acid, which was significantly different without MPs-PVC. These findings shed light on the complex interactions between MPs-PVC and MS2 in the UV-LED disinfection process under various water-quality parameters, contributing to drinking water safety and treatment.

Characterization of the microplastic photoaging under the action of typical salt ions of biological nitrogen removal processes

Microplastics (MPs) are one of the most prevalent and diverse contaminants, and wastewater treatment plants are significant MP aggregators. Controlling the pollution caused by microplastics requires an understanding of how they age. The properties of the MPs photoaging process under the influence of salt ions typical of biological nitrogen elimination processes were disclosed in this work. The aging process of polyvinyl chloride microplastics (PVC-MPs) was greatly slowed down by greater HCO3- and NO2- concentrations, according to a comparison of the carbonyl index changes that occurred during photoaging. The carbonyl index had a negative correlation with the thermal stability of the photo-aged PVC-MPs, and aging accelerated the elimination of chlorine from the water. The samples were aged by UV radiation after 36 h at 40 °C, and the amount of chlorine eliminated was 10.13 times greater than that of the original MPs samples. It was discovered that the leachate concentration of aged MPs dramatically increased with decreasing particle size and was positively connected with the level of aging by comparing the concentration of leachate for two particle sizes (1 mm and 100 m). Photoaging caused MPs to become rougher, which in turn improved the NO3--N, NH4+-N, and NO2--N adsorption by PVC-MPs.

Aging microplastics enhances the adsorption of pharmaceuticals in freshwater

Plastic pollution is an increasing environmental concern. Pollutants such as microplastics (< 5 mm) and pharmaceuticals often co-exist in the aquatic environment. The current study aimed to elucidate the interaction of pharmaceuticals with microplastics and ascertain how the process of photo-oxidation of microplastics affected the adsorption of the pharmaceuticals. To this end, a mixture containing ibuprofen, carbamazepine, fluoxetine, venlafaxine and ofloxacin (16 μmol L-1 each) was placed in contact with one of six either virgin or aged microplastic types. The virgin microplastics were acquired commercially and artificially aged in the laboratory. Polypropylene, polyethylene, polyethylene terephthalate, polyamide, polystyrene, and polyvinyl chloride microparticles at two sizes described as small (D50 < 35 μm) and large (D50 95-157 μm) were evaluated. Results demonstrated that the study of virgin particles may underestimate the adsorption of micropollutants onto microplastics. For virgin particles, only small microparticles of polypropylene, polyethylene, polyvinyl chloride, and both sizes of polyamide adsorbed pharmaceuticals. Aging the microplastics increased significantly the adsorption of pharmaceuticals by microplastics. Fluoxetine adsorbed onto all aged microplastics, from 18 % (large polyethylene terephthalate) to 99 % (small polypropylene). The current investigation highlights the potential of microplastics to act as a vector for pharmaceuticals in freshwater, especially after aging.

Latest trends and challenges in PVC and copper recovery technologies for End-of-Life thin cables

This review investigates the latest trends in separation technologies regarding hard-to-recycle thin cables, specifically in the form of end-of-life wire harnesses (WHs). The cables in WHs mainly contain copper (Cu) and poly(vinyl chloride) (PVC), which is commonly used to insulate and sheath cables. This review reveals that most separation technologies prioritize the recovery of Cu and overlook that of PVC. The recovery of high-purity PVC is very important because of its incompatibility with other plastics or Cu during recycling treatments. Through this investigation, we confirm that physical treatments, such as stripping and chopping, are insufficient to recover high-purity PVC from thin cables. Instead, a combination of chemical (e.g., swelling of PVC insulation or sheathing of cables under a suitable solvent) and physical (e.g., ball or rod milling and mechanical agitation of swollen cables) treatments can be used to achieve the recovery of high-purity PVC and Cu both for recycling. We believe that recovering metals and plastics from end-of-life cables is vital for sustainable waste management, offering several environmental and economic benefits.

Preparation of strong, tough and conductive soy protein isolate/poly(vinyl alcohol)-based hydrogel via the synergy of biomineralization and salting out

Conductive hydrogels have shown a great potential in the field of flexible electronic devices. However, conductive hydrogels prepare by traditional methods are difficult to combine high strength and toughness, which limits their application in various fields. In this study, a strategy for preparing conductive hydrogels with high strength and toughness by using the synergistic effect of biomineralization and salting-out was pioneered. In simple terms, by immersing the CaCl2 doped soy protein isolate/poly(vinyl alcohol)/dimethyl sulfoxide (SPI/PVA/DMSO) hydrogel in Na2CO3 and Na3Cit complex solution, the biomineralization aroused by Ca2+ and CO32-, and the salting-out effect of both NaCl and Na3Cit would enhance the mechanical properties of SPI/PVA/DMSO hydrogel. Meanwhile, the ionic conductivity of the hydrogel would also increase due the introduction of cation and anion. The mechanical and electrical properties of SPI/PVA/DMSO/CaCO3/Na3Cit hydrogels were significantly enhanced by the synergistic effect of biomineralization and salting-out. The optimum tensile strength, toughness, Young's modulus and ionic conductivity of the hydrogel were 1.4 ± 0.08 MPa, 0.51 ± 0.04 MPa and 1.46 ± 0.01 S/m, respectively. The SPI/PVA/DMSO/CaCO3/Na3Cit hydrogel was assembled into a strain sensor. The strain sensor had good sensitivity (GF = 3.18, strain in 20 %-500 %) and could be used to accurately detect various human movements.

Custom-designed polyphenol lignin for the enhancement of poly(vinyl alcohol)-based wood adhesive

Adhesives are used extensively in the wood industry. As resource and environmental issues become increasingly severe, the development of green and sustainable biomass-based adhesives has attracted increasing attention. In this work, a green wood adhesive is developed from poly(vinyl alcohol) and lignin with molecular designs of lignin extending beyond those in nature. The lignin undergoes extraction from corncob residue, aldehydration, and phenolisation (phenol, resorcinol, and catechol) to significantly increase the phenolic hydroxyl groups (over 7.92 mmol/g), which has the effect of enhancing the hydrogen bonding force between the adhesive and the wood, thereby greatly improving adhesive performance. Compared with pure PVA, polyphenol lignin-containing PVA showed improved adhesion strength and hydrophobicity. PVA/resorcinol-lignin has the significantly improved wood lap shear strength (6.27 MPa, 77.6 % improvement) and hydrophobicity (almost 100 % increase in wet shear strength). This research not only provides a green and high-performance alternative raw material for wood adhesives but also broadens the path for large-scale application of biomass.

Lignin/PVA hydrogel with enhanced structural stability for cationic dye removal

In this study, a lignin-based hydrogel for wastewater treatment was prepared by incorporating kraft lignin (KL) into a poly (vinyl alcohol) (PVA) matrix. The underwater structural stability of the KL-PVA hydrogel was guaranteed through physicochemical crosslinking, involving freeze-thaw process and chemical crosslinking reaction. The KL-PVA hydrogel displayed superior compressive characteristics compared to the original PVA hydrogel. This improvement was attributed to the chemical crosslinking and the reinforcing effect of the incorporated KL microparticles. The incorporation of anionic KL microparticles into the PVA three-dimensional network structure enhanced the cationic methylene blue (MB) and crystal violet (CV) adsorption efficiency of the prepared KL-PVA hydrogel. The MB adsorption results were well explained by pseudo-2nd order kinetics model and Langmuir isotherm model. Electrostatic forces, hydrogen bonding and π-π stacking interactions were the main adsorption mechanisms between cationic dyes and KL surfaces, indicating the potential of KL-PVA hydrogel as an effective adsorption material. Moreover, regulating the molecular weight of PVA not only prevented lignin leakage from the KL-PVA hydrogel but also elevated the KL content within the hydrogel, consequently improving its dye removal performance. For KL-PVA hydrogel with high molecular weight PVA, the MB and CV adsorption capacities were 193.8 mg/g and 190.0 mg/g, respectively.

The Triumph of the Spin Chemistry of Fullerene C60 in the Light of Its Free Radical Copolymerization with Vinyl Monomers

The spin theory of fullerenes is taken as a basis concept to virtually exhibit a peculiar role of C60 fullerene in the free radical polymerization of vinyl monomers. Virtual reaction solutions are filled with the initial ingredients (monomers, free radicals, and C60 fullerene) as well as with the final products of a set of elementary reactions, which occurred in the course of the polymerization. The above objects, converted to the rank of digital twins, are considered simultaneously under the same conditions and at the same level of the theory. In terms of the polymerization passports of the reaction solutions, a complete virtual picture of the processes considered is presented.

A Novel Fabrication of Heterogeneous Saponified Poly(Vinyl Alcohol)/Pullulan Blend Film for Improved Wound Healing Application

In this study, a novel film of poly(vinyl alcohol) (PVA)/pullulan (PULL) with improved surface characteristics was prepared from poly(vinyl acetate) (PVAc)/PULL blend films with various mass ratios after the saponification treatment in a heterogeneous medium. According to proton nuclear magnetic resonance (1H-NMR), Fourier transform infrared, and X-ray diffraction results, it was established that the successful fabrication of saponified PVA/PULL (100/0, 90/10, and 80/20) films could be obtained from PVAc/PULL (100/0, 90/10, and 80/20) films, respectively, after 72 h saponification at 50 °C. The degree of saponification calculated from 1H-NMR analysis results showed that fully saponified PVA was obtained from all studied films. Improved hydrophilic characteristics of the saponified films were revealed by a water contact angle test. Moreover, the saponified films showed improved mechanical behavior, and the micrographs of saponified films showed higher surface roughness than the unsaponified films. This kind of saponified film can be widely used for biomedical applications. Moreover, the reported saponified film dressing extended the lifespan of dressing as determined by its self-healing capacity and considerably advanced in vivo wound-healing development, which was attributed to its multifunctional characteristics, meaning that saponified film dressings are promising candidates for full-thickness skin wound healing.

In vitro hemocompatibility screening of a slippery liquid impregnated surface coating for extracorporeal organ support applications

INTRODUCTION

Clot formation, infection, and biofouling are unfortunate but frequent complications associated with the use of blood-contacting medical devices. The challenge of blood-foreign surface interactions is exacerbated during medical device applications involving substantial blood contact area and extended duration of use, such as extracorporeal life support (ECLS). We investigated a novel surface modification, a liquid-impregnated surface (LIS), designed to minimize protein adsorption and thrombus development on medical plastics.

METHODS

The hemocompatibility and efficacy of LIS was investigated first in a low-shear model with LIS applied to the lumen of blood incubation vials and exposed to human whole blood. Additionally, LIS was evaluated in a 6 h ex vivo circulation model with swine blood using full-scale ECLS circuit tubing and centrifugal pumps with clinically relevant flow rate (1.5 L/min) and shear conditions for extracorporeal carbon dioxide removal.

RESULTS

Under low-shear, LIS preserved fibrinogen concentration in blood relative to control polymers (+40 ± 6 mg/dL vs polyvinyl chloride, p < .0001), suggesting protein adsorption was minimized. A fibrinogen adhesion assay demonstrated a dramatic reduction in protein adsorption under low shear (87% decrease vs polyvinyl chloride, p = .01). Thrombus deposition and platelet adhesion visualized by scanning electron microscopy were drastically reduced. During the 6 h ex vivo circulation, platelets in blood exposed to LIS tubing did not become significantly activated or procoagulant, as occurred with control tubing; and again, thrombus deposition was visually reduced.

CONCLUSIONS

A LIS coating demonstrated potential to reduce thrombus formation on medical devices. Further testing is needed specialized to clinical setting and duration of use for specific medical target applications.

Small microplastic particles promote tetracycline and aureomycin adsorption by biochar in an aqueous solution

Biochar (BC) has been used to remove antibiotics from wastewater. Microplastics are emerging contaminants of wastewater. The capacities of microplastics for adsorbing antibiotics and the effects of microplastics of different types and particle sizes on antibiotic adsorption by BC have not been studied. Here, adsorption isotherm and kinetics experiments were performed to investigate tetracycline and aureomycin adsorption to polyvinyl chloride particles with diameters of 10, 100, 500, and 2000 μm, polylactic acid particles with diameters of 30, 100, 500, and 2000 μm (PLA30, PLA100, PLA500, and PLA2000, respectively), and wheat straw BC. The highest tetracycline adsorption capacity (25.00 mg g-1) was found for a PLA30 + BC. The tetracycline adsorption capacities of the other microplastic particles were 20.44-24.57 mg g-1. The highest aureomycin adsorption capacity (39.50 mg g-1) was found for 10 μm polyvinyl chloride particles and BC. The aureomycin adsorption capacities of the other microplastic particles were 32.21-38.42 mg g-1. The tetracycline adsorption capacities were 13.69%, 6.28%, 5.49%, and 4.54% higher for PLA30 + BC, PLA100 + BC, PLA500 + BC, and PLA2000 + BC, respectively, than for only BC. This may have been because there were more sites available per unit mass of microplastic for adsorbing tetracycline and dissolved organic carbon on small microplastic particles than large microplastic particles. The results indicated that microplastics can adsorb antibiotics and increase the amounts of antibiotics adsorbed by BC. Therefore, it is essential to consider potential interactions between BC and microplastics when BC is used to remove antibiotics from wastewater.

Surface modification of polyvinyl chloride with sodium alginate/carboxymethyl chitosan and heparin for realizing the anticoagulation

Thrombosis of extracorporeal circuits causes significant morbidity and mortality worldwide. In this study, plasma treatment technology and chemical grafting method were used to construct heparinized surfaces on the PVC substrate, which could not only reduce thrombosis but also decrease the side effects of the direct injection of anticoagulants. The PVC substrate was modified by plasma treatment technology firstly to obtain the active surface with the hydroxyl groups used for grafting. Then, heparin was grafted onto the modified PVC surface using different grafting strategies to prepare different heparinized surfaces. The experimental results indicated that the sodium alginate (SA) and carboxymethyl chitosan (CCS) used as interlayers could significantly increase the graft density of heparin to improve the anticoagulant effects and hemocompatibility of heparinized surfaces. In addition, the modification of heparin can further improve the anticoagulant effects. The CCS/low-molecular-weight heparin (LWMH) surface has the best anticoagulant properties, which can prolong the activated partial thromboplastin time (APTT) values of human plasma for about 35 s, reduce the hemolysis rates to <0.3 %, and perform well in the in-vitro blood circulation test. The heparinized surfaces prepared in this work have great application potential in anticoagulant treatment for medical devices.

Development of an anatomical breast phantom from polyvinyl chloride plastisol with lesions of various shape, elasticity and echogenicity for teaching ultrasound examination

PURPOSE

The WHO reported an increasing trend in the number of new cases of breast cancer, making it the most prevalent cancer in the world. This fact necessitates the availability of highly qualified ultrasonographers, which can be achieved by the widespread implementation of training phantoms. The goal of the present work is to develop and test an inexpensive, accessible, and reproducible technology for creating an anatomical breast phantom for practicing ultrasound diagnostic skills in grayscale and elastography imaging, as well as ultrasound-guided biopsy sampling.

METHODS

We used FDM 3D printer and PLA plastic for printing an anatomical breast mold. We made a phantom using a mixture of polyvinyl chloride plastisol, graphite powder, and metallic glitter to simulate soft tissues and lesions. Various degrees of elasticity were imparted using plastisols of stiffness ranging from 3 to 17 on the Shore scale. The lesions were shaped by hand. The materials and methods used are easily accessible and reproducible.

RESULTS

Using the proposed technology, we have developed and tested a basic, differential, and elastographic versions of the breast phantom. The three versions of the phantom are anatomical and intended for use in medical education: the basic version is for practicing primary hand-eye coordination skills; the differential one is for practicing the differential diagnosis skills; the elastographic version helps developing the skills needed for assessing the stiffness of tissues.

CONCLUSION

The proposed technology allows the creation of breast phantoms for practicing hand-eye coordination and develop the critical skills for navigation and assessment of the shape, margins, and size of the lesion, as well as performing an ultrasound-guided biopsy. It is cost-effective, reproducible, and easily implementable, and could be instrumental in generating ultrasonographers with crucial skills for accurate diagnosis of breast cancer, especially in low-resource settings.

Ease of endotracheal intubation with the conventional polyvinyl chloride endotracheal tube versus wire-reinforced flexometallic tube through the intubating laryngeal mask airway: A comparative study

Background The I-LMA ventilates while providing a port for blind insertion of an endotracheal tube. The ILMA Fastrach is used especially for intubating in a difficult airway scenario. Its accompanying endotracheal tube is not economical nor readily available. In comparison, two alternative endotracheal tubes - polyvinyl chloride and wire-reinforced tubes were used for tracheal intubation through the ILMA.

AIMS AND OBJECTIVES

The aim of our study was to compare the ease of intubation when using conventional PVC tubes versus the wire-reinforced flexometallic tubes with the ILMA-FastrachTM. The number of attempts, time taken and additional maneuvers were noted. Intra-operative hemodynamic changes, post-operative sore throat, bleeding and hoarseness of voice was recorded over a period of 24 hours.

METHODOLOGY

After informed consent, 60 ASA I-II patients undergoing elective surgeries under general anesthesia were allocated to undergo blind intubation with the PVC tube or the wire-reinforced flexometallic tube.

RESULTS

More attempts were required for successful intubation using the wire-reinforced tube than the PVC tube with 76.7% passing in the first attempt in the PVC, and 53.3% passing in the first attempt in the flexometallic group. (P = 0.4). Average time for intubation in the PVC group: 28.24 ± 7.22 seconds. Average time for intubation in the flexometallic tube: 45.8 ± 15.78 sec. Occurrence of post-operative sore throat was 13.3% in the PVC group and 26.6% in the flexometallic group, with minimal hoarseness of voice 3.3% in the PVC group and 10% in the flexometallic group. There was also a slightly higher hemodynamic response in those who were intubated with the flexometallic tube than a PVC tube.

CONCLUSION

Intubating via the ILMA-Fastrach with the PVC tube offered better intubating conditions with regards to lesser time taken, lesser attempts, less manipulation, and less hemodynamic variations as compared to the patients who were intubated using the wire-reinforced tube.

Electrospun Cactus Mucilage/Poly(vinyl alcohol) Nanofibers as a Novel Wall Material for Dill Seed Essential Oil (Anethum graveolens L.) Encapsulation: Release and Antibacterial Activities

This study aimed to create long-lasting carriers by producing electrospun nanofibers loaded with dill seed (Anethum graveolens L.) essential oil (DSEO), using cactus mucilage (CM) and poly(vinyl alcohol) (PVA). Continuous and uniform electrospun nanofibers with a diameter of 158 ± 18 to 230 ± 26 nm were successfully made from the CM/PVA blend solution and the CM/PVA/DSEO emulsion. Atomic force microscopy topographic images revealed that the electrospun nanofibers had a tubular morphology. The thermogravimetric curves of DSEO, CM, pure PVA, and electrospun nanofibers demonstrate that the polymers used and the essential oil have effective chemical interactions. The water contact angle results suggest that the manufactured nanofibers are hydrophilic. CM/PVA consistently achieves a remarkable encapsulation efficiency of 100% DSEO. The electrospun nanofibers enabled the controlled release of free and encapsulated DSEO, resulting in sustained long-term release. The agar disk diffusion technique was used to study the antimicrobial activity of electrospun nanofibers and nanofibers containing DSEO against Gram-positive and Gram-negative bacteria. With a minimum inhibitory concentration of 2.5 mg/mL and a minimum bactericidal concentration of 5 mg/mL, electrospun nanofibers containing DSEO demonstrated bacteriostatic and bactericidal activities against foodborne pathogenic bacteria (Staphylococcus aureus and Pseudomonas aeruginosa). The DSEO-loaded electrospun nanofibers derived from carbohydrates show promise as an active interior coating for use in biomedical and food packaging applications.

The effect of polyvinyl chloride (PVC) color on biofilm development and biofilm-heavy metal chemodynamics in the aquatic environment

Plastic surfaces are colonized by microorganisms and biofilms are formed in the natural aquatic environment. As the biofilm develops, it changes the density and buoyancy of the plastic-biofilm complex, results in plastic sinking, and increases the heavy metals accumulated by biofilm's mobility and availability in aquatic ecosystems. In this experiment, biofilms were cultured on five colors of polyvinyl chloride (PVC; transparent, green, blue, red, black) in an aquatic environment to investigate the effects of plastic color on biofilm formation and development (Phase 1) and to study the effects of being sunk below the photic zone on biofilm (Phase 2). The PVC color significantly affected the biofilm formation rate but had no impact on the final biofilm biomass. After sinking the biofilm-PVC below the photic zone in Phase 2, the layer of diatoms on the biofilm surface began to disintegrate, and the biomass and Chlorophyll-a (Chla) content of the biofilm decreased, except on the red PVC. Below the photic zone, the microbial community of the biofilm changed from primarily autotrophic microbes to mostly heterotrophic microbes. Microbial diversity increased and extracellular polymeric substances (EPS) content decreased. The primary factor leading to microbial diversity and community structure changes was water depth rather than PVC color. The changes induced in the biofilm led to an increase in the concentration of all heavy metals in the biofilm, related to the increase in microbial diversity. This study provides new insights into the biofilm formation process and the effects on a biofilm when it sinks below the photic zone.

Revealing How Polyvinyl Chloride Microplastic Physicochemically Affect the Anaerobic Digestion of Waste Activated Sludge

Recent studies have shown that the microplastics in waste activated sludge (WAS) can directly reduce the microbial activity and influence the performance of anaerobic digestion. Unfortunately, few studies paid attention on the interactions between WAS and MPs, since MPs could impact the contact between sludge flocs and microorganisms. We found that PVC-MP changed the interfacial energy properties of the WAS surface and affected methane production. Low concentration (40 mg/L) of PVC-MP changed the water affinity and greatly reduced the energy barrier of interfacial reaction. Simultaneously, WAS surface charge characteristics changed with increasing MPs concentration, which made the sludge difficult to contact with microorganisms. The change process of WAS surface functional groups also indicated that PVC-MP first cover the sludge surface to prevent from being utilized by microorganisms, and then affect the surface protein structure before toxic substances leaching. Our study provides new insights into how MPs affect anaerobic digestion.

Effects of polyvinylchloride microplastics on the toxicity of nanoparticles and antibiotics to aerobic granular sludge: Nitrogen removal, microbial community and resistance genes

Copper oxide nanoparticles (CuO NPs) and ciprofloxacin (CIP) have ecological risk to humans and ecosystems. Polyvinylchloride microplastics (PVC MPs), as a representative of microplastics, may often coexist with CuO NPs and CIP in wastewater treatment systems due to their widespread application. However, the co-impact of PVC MPs in wastewater systems contained with CuO NPs and CIP on nitrogen removal and ecological risk is not clear. In this work, PVC MPs co-impacts on the toxicity of CuO NPs and CIP to aerobic granular sludge (AGS) systems and potential mechanisms were investigated. 10 mg/L PVC MPs co-addition did not significantly affect the nitrogen removal, but it definitely changed the microbial community structure and enhanced the propagation and horizontal transfer of antibiotics resistance genes (ARGs). 100 mg/L PVC MPs co-addition resulted in a raise of CuO NP toxicity to the AGS system, but reduced the co-toxicity of CuO NPs and CIP and ARGs expression. The co-impacts with different PVC MPs concentration influenced Cu2+ concentrations, cell membrane integrity, extracellular polymeric substances (EPS) contents and microbial communities in AGS systems, and lead to a change of nitrogen removal.

Ionophore-Based Polymeric Sensors for Potentiometric Assay of the Anticancer Drug Gemcitabine in Pharmaceutical Formulation: A Comparative Study

Gemcitabine is a chemotherapeutic agent used to treat various malignancies, including breast and bladder cancer. In the current study, three innovative selective gemcitabine hydrochloride sensors are developed using 4-tert-butylcalix-[8]-arene (sensor 1), β-cyclodextrin (sensor 2), and γ-cyclodextrin (sensor 3) as ionophores. The three sensors were prepared by incorporating the ionophores with o-nitrophenyl octyl ether as plasticizer and potassium tetrakis(4-chlorophenyl) borate as ionic additive into a polyvinyl chloride polymer matrix. These sensors are considered environmentally friendly systems in the analytical research. The linear responses of gemcitabine hydrochloride were in the concentration range of 6.0 × 10-6 to 1.0 × 10-2 mol L-1 and 9.0 × 10-6 to 1.0 × 10-2 mol L-1 and 8.0 × 10-6 to 1.0 × 10-2 mol L-1 for sensors 1, 2, and 3, respectively. Over the pH range of 6-9, fast-Nernst slopes of 52 ± 0.6, 56 ± 0.3, and 55 ± 0.8 mV/decade were found in the same order with correlation regressions of 0.998, 0.999, and 0.998, respectively. The lower limits of detection for the prepared sensors were 2.5 × 10-6, 2.2 × 10-6, and 2.7 × 10-6 mol L-1. The sensors showed high selectivity and sensitivity for gemcitabine. Validation of the sensors was carried out in accordance with the requirements established by the IUPAC, while being inexpensive and easy to use in drug formulation. A statistical analysis of the methods in comparison with the official method showed that there was no significant difference in accuracy or precision between them. It was shown that the new sensors could selectively and accurately find gemcitabine hydrochloride in bulk powder, pharmaceutical formulations, and quality control tests. The ionophore-based sensor shows several advantages over conventional PVC membrane sensor sensors regrading the lower limit of detection, and higher selectivity towards the target ion.

Biodegradation of polyvinyl chloride, polystyrene, and polylactic acid microplastics in Tenebrio molitor larvae: Physiological responses

It is widely understood that microplastics (MPs) can induce various biological stresses in macroinvertebrates that are incapable of biodegrading plastics. However, the biodegradation and physiological responses of plastic-degrading macroinvertebrates toward MPs of different degradability levels remain unexplored. In this study, Tenebrio molitor larvae (mealworms) were selected as a model of plastics-degrading macroinvertebrate, and were tested against three common plastics of different degradability rankings: polyvinyl chloride (PVC), polystyrene (PS), and polylactic acid (PLA) MPs (size <300 μm). These three MPs were biodegraded with the rate sequence of PLA > PS > PVC, resulting in a reversed order of negative physiological responses (body weight loss, decreased survival, and biomass depletion) of mealworms. Simultaneously, the levels of reactive oxygen species (ROS), antioxidant enzyme activities, and lipid peroxidation were uniformly increased as polymer degradability decreased and intermediate toxicity increased. PVC MPs exhibited higher toxicity than the other two polymers. The oxidative stresses were effectively alleviated by supplementing co-diet bran. The T. molitor larvae fed with PLA plus bran showed sustainable growth without an increase in oxidative stress. The results provide new insights into the biotoxicity of MPs on macroinvertebrates and offer comprehensive information on the physiological stress responses of plastic-degrading macroinvertebrates during the biodegradation of plastics with different degradability levels.

Optimizing Eco-Friendly Degradation of Polyvinyl Chloride (PVC) Plastic Using Environmental Strains of Malassezia Species and Aspergillus fumigatus

Worldwide, huge amounts of plastics are being introduced into the ecosystem, causing environmental pollution. Generally, plastic biodegradation in the ecosystem takes hundreds of years. Hence, the isolation of plastic-biodegrading microorganisms and finding optimum conditions for their action is crucial. The aim of the current study is to isolate plastic-biodegrading fungi and explore optimum conditions for their action. Soil samples were gathered from landfill sites; 18 isolates were able to grow on SDA. Only 10 isolates were able to the degrade polyvinyl chloride (PVC) polymer. Four isolates displayed promising depolymerase activity. Molecular identification revealed that three isolates belong to genus Aspergillus, and one isolate was Malassezia sp. Three isolates showed superior PVC-biodegrading activity (Aspergillus-2, Aspergillus-3 and Malassezia) using weight reduction analysis and SEM. Two Aspergillus strains and Malassezia showed optimum growth at 40 °C, while the last strain grew better at 30 °C. Two Aspergillus isolates grew better at pH 8-9, and the other two isolates grow better at pH 4. Maximal depolymerase activity was monitored at 50 °C, and at slightly acidic pH in most isolates, FeCl3 significantly enhanced depolymerase activity in two Aspergillus isolates. In conclusion, the isolated fungi have promising potential to degrade PVC and can contribute to the reduction of environmental pollution in eco-friendly way.

Adsorption of tetracycline on polyvinyl chloride microplastics in aqueous environments

Microplastics (MPs), as carriers of organic pollutants in the environment, have become a growing public concern in recent years. Tetracycline (TTC) is an antibiotic that can be absorbed by MPs and have a harmful effect on human health. Therefore, this study was conducted with the aim of investigating the adsorption rate of TTC onto polyvinyl chloride (PVC) MPs. In addition, the adsorption mechanism of this process was studied using isothermal, kinetic, and thermodynamic models. For this purpose, experimental runs using the Box-Behnken model were designed to investigate the main research parameters, including PVC dose (0.5-2 g/L), reaction time (5-55 min), initial antibiotic concentration (5-15 mg/L), and pH (4-10). Based on the research findings, the highest TTC adsorption rate (93.23%) was obtained at a pH of 10, a contact time of 55 min, an adsorbent dose of 1.25 g/L, and an antibiotic concentration of 10 mg/L. The study found that the adsorption rate of TTC followed the pseudo-second-order and Langmuir models. Thermodynamic data indicated that the process was spontaneous, exothermic, and physical. Increasing ion concentration decreased TTC adsorption, and distilled water had the highest adsorption, while municipal wastewater had the lowest adsorption. These findings provide valuable insights into the behavior of MPs and organic pollutants, underscoring the importance of conducting additional research and implementing measures to mitigate their detrimental effects on human health and the environment.

Phthalate acid esters promoted the enrichment of chlorine dioxide-resistant bacteria and their functions related to human diseases in rural polyvinyl chloride distribution pipes

Polyvinyl chloride (PVC) pipes are widely used as drinking water distribution pipes in rural areas of China. However, whether phthalate acid esters (PAEs) released from PVC pipes will affect tap water quality is still unknown. The influence of released PAEs on the water quality was analysed in this study, especially after ClO2 disinfection. The results indicated that ClO2 disinfection could control the growth of total coliforms and heterotrophic bacteria (HPC). However, when the ClO2 residual decreased to below 0.10 mg/L, HPC and opportunistic pathogens, including Mycobacterium avium and Pseudomonas aeruginosa, increased significantly. In addition, after ClO2 disinfection, PAEs concentrations increased from 10.6-22.2 μg/L to 21.2-58.8 μg/L in different sampling cites. Linear discriminant analysis (LDA) effect size (LEfSe) and statistical analysis of metagenomic profiles (Stamp) showed that ClO2 disinfection induced the enrichment of Pseudomonas, Bradyrhizobium, and Mycobacterium and functions related to human diseases, such as pathogenic Escherichia coli infection, shigellosis, Staphylococcus aureus infection, and Vibrio cholerae infection. The released PAEs not only promoted the growth of these ClO2-resistant bacterial genera but also enhanced their functions related to human diseases. Moreover, these PAEs also induced the enrichment of other bacterial genera, such as Blastomonas, Dechloromonas, and Kocuria, and their functions, such as chronic myeloid leukaemia, African trypanosomiasis, leishmaniasis, hepatitis C and human T-cell leukaemia virus 1 infection. The released PAEs enhanced the microbial risk of the drinking water. These results are meaningful for guaranteeing water quality in rural areas of China.

3D dynamic tracking Aβ plaques in live brains using vinyl-bridged dyes with two-photon excitation/NIR emission and large Stokes shifts

Real-time studies of biomarkers for neurological disorders present significant opportunities for diagnosing and treating related diseases, and fluorescent probes offer a promising approach to brain imaging. However, intracerebral fluorescence imaging is often limited by blood-brain barrier permeability and penetration depth. Moreover, only very few probes have rapid intracerebral metabolic properties, which are critical for in vivo imaging. Here, we developed a novel class of fluorescent dyes with two-photon excitation and near-infrared (NIR) emission (920/705 nm). The representative WAPP-4 probe exhibits a large Stokes shift (Δλ = 324 nm in ethanol) and excellent blood-brain barrier permeability. Notably, using WAPP-4, we achieved in vivo 3D dynamic imaging of Aβ plaques in the brains of living mice with Alzheimer's disease (AD). In addition, super-resolution imaging showed that WAPP-4 could effectively characterize the distribution and shape of Aβ plaques in isolated brain slices. This study demonstrates that newly developed fluorescent dyes with large Stokes shifts and blood-brain barrier permeability enable real-time imaging of amyloid plaques, which will contribute to the development of other valuable tools for near-infrared imaging and super-resolution imaging in the brain.

Mechanical response of composite materials prepared with polyurethane elastomers and polyvinyl chloride films

This study describes a new method for the preparation of composite materials using polyvinyl chloride (PVC) films and polyurethane (PU) foam elastomers. This new preparation method was applied to composite materials used for sound and thermal insulation in the automotive and aerospace industries, and it was found to be effective in reducing debonding and fracture defects. This feature was achieved via the formation of through-holes in the surface material and the substrate prior to lamination, which led to the increase in the flow of air and adhesive and allowed for better compatibility between the material layers. The composite material shows a tensile strength of up to 37.6 Kg⋅cm-2 and can achieve a tensile fracture strength of up to 281.3 N, if woven or biomaterials are used. This can be useful in solving challenges in the aerospace and automotive industries and may also act as a potential coating material for other applications in the future.

Sunlight filtered via translucent-colored polyvinyl chloride sheets enhanced the light absorption capacity and growth of Arthrospira platensis cultivated in a pilot-scale raceway pond

In this research, the effects of filtered sunlight traveling through translucent-colored polyvinyl chloride (PVC) sheets on the photoconversion efficiency of Arthrospira platensis are investigated. Filtered sunlight improves the phycobilisome's capacity to completely absorb and transport it to intracellular photosystems. Findings indicated that filtered sunlight via orange-colored PVC sheet increased biomass dry weight by 21% (2.80 g/L), while under blue-colored PVC sheet decreased by 32% (1.49 g/L), when compared with translucent-colored (control) PVC sheet (2.19 g/L) after 120 h of culture. The meteorological conditions during the 1st week of cultivation reported higher light flux than the subsequent weeks. Furthermore, sunlight filtered through orange PVC sheet enhanced protein, allophycocyanin, phycocyanin, chlorophyll-a and carotenoids synthesis by 13%, 15%, 13%, 22%, and 27%, respectively. This practical and inexpensive solar radiation filtration system supports large-scale production of tailored bioactive compounds from microalgae with high growth rate.

Potential transmission of SARS-CoV-2 through microplastics in sewage: A wastewater-based epidemiological review

In light of the current COVID-19 pandemic caused by the virus SARS-CoV-2, there is an urgent need to identify and investigate the various pathways of transmission. In addition to contact and aerosol transmission of the virus, this review investigated the possibility of its transmission via microplastics found in sewage. Wastewater-based epidemiological studies on the virus have confirmed its presence and persistence in both influent sewage as well as treated ones. The hypothesis behind the study is that the huge amount of microplastics, especially Polyvinyl Chloride and Polyethylene particles released into the open waters from sewage can become a good substrate and vector for microbes, especially Polyvinyl Chloride and Polyethylene particles, imparting stability to microbes and aiding the "plastisphere" formation. A bibliometric analysis highlights the negligence of research toward plastispheres and their presence in sewage. The ubiquity of microplastics and their release along with the virus into the open waters increases the risk of viral plastispheres. These plastispheres may be ingested by aquatic organisms facilitating reverse zoonosis and the commercial organisms already reported with accumulating microplastics through the food chain poses a risk to human populations as well. Reliance of high population density areas on open waters served by untreated sewage in economically less developed countries might bring back viral transmission.

Chironomus riparius Larval Gut Bacteriobiota and Its Potential in Microplastic Degradation

Chironomus riparius are sediment-dwelling invertebrates in freshwater ecosystems and are used as indicators of environmental pollution. Their habitat is threatened by high levels of contaminants such as microplastics and organic matter. A promising strategy for the eco-friendly degradation of pollutants is the use of bacteria and their enzymatic activity. The aim of this study was to characterize for the first time bacteriobiota associated with the gut of C. riparius larvae from nature and laboratory samples, to compare it with sediment and food as potential sources of gut microbiota, and to assess its ability to degrade cellulose, proteins, and three different types of microplastics (polyethylene, polyvinyl chloride, and polyamide). The metabarcoding approach highlighted Proteobacteria, Firmicutes, Bacteroidota, and Actinobacteriota as most abundant in both gut samples. Culturable microbiota analysis revealed Metabacillus idriensis, Peribacillus simplex, Neobacillus cucumis, Bacillus thuringiensis/toyonensis, and Fictibacillus phosphorivorans as five common species for nature and laboratory samples. Two P. simplex and one P. frigoritolerans isolates showed the ability for intensive growth on polyethylene, polyvinyl chloride, and polyamide. Both cellulolytic and proteolytic activity was observed for Paenibacillus xylanexedens and P. amylolyticus isolates. The characterized strains are promising candidates for the development of environmentally friendly strategies to degrade organic pollution and microplastics in freshwater ecosystems.

Multiscale Relaxation Behavior of Amorphous Plasticized Poly(vinyl butyral)

As a key component in laminated glass, plasticized polyvinyl butyral (PVB) interlayer is a kind of impact-resistant polymer material with high toughness. Recently, by using ultrasmall angle X-ray scattering (USAXS) technique, Stretch-induced phase-separated structure on the scale of hundreds of nanometers formed in plasticized PVB for the first time is reported. In this work, the multiscale relaxation behavior of plasticized PVB is further investigated. The relaxation behavior of deformed plasticized PVB is studied from macroscopic stress, mesoscopic phase-separated structure, and microscopic chain segment by combining USAXS, and birefringence with in situ stretching device. The contributions of chain segments and hydrogen bonding clusters for the multiscale relaxation behavior are discussed.

Evaluation of physical properties and image of polyvinyl chloride as breast tissue equivalence for dual-modality (mammography and ultrasound)

TMP is gradually becoming a fundamental element for quality assurance and control in ionizing and non-ionizing radiation imaging modalities as well as in the development of different techniques. This study aimed to evaluate and obtain polyvinyl chloride tissue mimicking material for dual-modality breast phantoms in mammography and ultrasound. Breast tissue equivalence was evaluated based on X-ray attenuation properties, speed of sound, attenuation, and acoustic impedance. There are six samples of PVC-plasticizer material with variations of PVC concentration and additives. The evaluation of X-ray attenuation was carried out using mammography from 23 to 35 kV, while the acoustic properties were assessed with mode A ultrasound and a transducer frequency of 5 MHz. A breast phantom was created from TMP material with tissue equivalence and was then evaluated using mammography as well as ultrasound to analyze its image quality. The results showed that samples A (PVC 5%, DOP 95%), B (PVC 7%, DOP 93%), C (PVC 10%, DOP 90%), E (PVC 7%, DOP 90%, graphite 3%), and F (PVC 7%, DOP 90%, silicone oil 3%) have the closest equivalent to the ACR breast phantom material with a different range of 0.01-1.39 in the 23-35 kV range. Based on the evaluation of the acoustic properties of ultrasound, A had high similarity to fat tissue with a difference of 0.03 (dB cm- 1 MHz- 1) and 0.07 (106 kg m- 2 s- 1), while B was close to the glandular tissue with a difference of 9.2 m s- 1. Multilayer breast phantom images' results showed gray levels in mammography and ultrasound modalities. Therefore, this study succeeded in establishing TMP material for mammography and ultrasound. It can also be used for simple quality assurance and control programs.

Role of acidic hydrochar on dechlorination of waste PVC in high temperature hydrothermal treatment and fuel properties enhancement of solid residues

In this study, the chlorine mitigation from waste polyvinyl chloride (WPVC) during high temperature co-hydrothermal treatment (co-HTT) and the properties of the generated solid products were assessed. WPVC was co-fed with acidic hydrochar (AHC), which was produced via hydrothermal carbonization of pineapple waste in the presence of citric acid water solution. High temperature co-HTT experiments were performed at 300-350 °C, 0.25-4 h of reaction time, and 0-20 wt% AHC loading. Co-HTT solid products (co-HTT_SP) were characterized via proximate analysis, ultimate analyses, combustion analysis, and ash analysis. The results show that the addition of 5% AHC enhances the dechlorination efficiency (DE) of WPVC from 89.35% to 97.66% at 325 °C and 0.5 h. The highest DE, reaching 99.46%, was achieved at 350 °C and 1 h in the presence of 5 wt% AHC. Furthermore, loading 5% AHC improved the higher heat value (HHV) of the solid products from 23.09 to 31.25 MJ/kg at 325 °C and 0.5 h. The maximum HHV (34.77 MJ/kg) of a solid product was achieved at 350 °C, 4 h, in the presence of 5 wt% of AHC. The co-HTT solids shown low slagging indices, fouling indices, alkali indices, and medium chlorine contents. These findings support the viability of WPVC conversion into clean solid fuel via co-HTT.

Unraveling the comonomer distribution in ethylene - vinyl ester terpolymers through liquid chromatography with infrared detection

Polyolefins are the most commercially relevant polymers by volume. A readily available feedstock and their tailor-made microstructure allow to adapt polyolefins to many fields of application. Important molecular design features of olefin copolymers are the molar mass distribution (MMD) with the corresponding average values, comonomer type, chemical composition distribution (CCD) with the corresponding average and the tacticity distribution (TD). Advanced separation techniques i.e., high-temperature gel permeation chromatography (HT-GPC) as well as its hyphenation with high-temperature high performance liquid chromatography (HT-HPLC) in the form of high-temperature two-dimensional liquid chromatography (HT 2D-LC) have been successfully applied in this work. This allowed to deeply analyze the molecular heterogeneities of complex polyolefin terpolymers consisting of ethylene, vinyl acetate and branched vinyl ester monomers. By using filter-based infrared detection, the capabilities of HT-GPC are further extended so that the distribution of methyl- and carbonyl groups could be obtained along the molar mass axis. Using porous graphitic carbon (PGC) as a stationary phase for HT-HPLC separation provided information about the CCD of these complex polyolefins from experimental data as part of the hyphenated approach of HT 2D-LC. The latter revealed the full MMD x CCD distribution function, which is the key for a comprehensive analysis of the bivariate molecular structure of the polyolefin terpolymers.

Activation of Pyroptosis Using AIEgen-Based sp2 Carbon-Linked Covalent Organic Frameworks

Covalent organic frameworks (COFs) have emerged as a promising class of crystalline porous materials for cancer phototherapy, due to their exceptional characteristics, including light absorption, biocompatibility, and photostability. However, the aggregation-caused quenching effect and apoptosis resistance often limit their therapeutic efficacy. Herein, we demonstrated for the first time that linking luminogens with aggregation-induced emission effect (AIEgens) into COF networks via vinyl linkages was an effective strategy to construct nonmetallic pyroptosis inducers for boosting antitumor immunity. Mechanistic investigations revealed that the formation of the vinyl linkage in the AIE COF endowed it with not only high brightness but also strong light absorption ability, long lifetime, and high quantum yield to favor the generation of reactive oxygen species for eliciting pyroptosis. In addition, the synergized system of the AIE COF and αPD-1 not only effectively eradicated primary and distant tumors but also inhibited tumor recurrence and metastasis in a bilateral 4T1 tumor model.

Environmental factors strongly influence the leaching of di(2-ethylhexyl) phthalate from polyvinyl chloride microplastics

Phthalic acid esters (phthalates) are an important group of additives (plasticizers) to ensure the flexibility and stability especially of polyvinyl chloride (PVC) and to enable its processing. However, phthalates like di(2-ethylhexyl) phthalate (DEHP) are harmful for aquatic organisms due to their endocrine disrupting effects and toxicity. For the assessment of exposure concentrations, thorough understanding of leaching kinetics of phthalates from PVC (micro-) plastics into aqueous environments is necessary. This study investigates how environmental factors influence the leaching of phthalates from PVC microplastics into aquatic systems. The leaching of phthalates from PVC microplastics into aqueous media is limited by aqueous boundary layer diffusion (ABLD) and thus, process-specific parameters can be affected by environmental factors such as salinity and the flow conditions. We conducted batch leaching experiments to assess the influence of salinity and flow conditions (turbulence) on the leaching of DEHP from PVC microplastics into aqueous media. DEHP is salted out with increasing salinity of the solution and a salting-out coefficient for DEHP of 0.46 was determined. The partitioning coefficient of DEHP between PVC and water KPVC/W increased with increasing salinity from 108.52 L kg-1 in a 1 mM KCl solution to 108.75 L kg-1 in artificial seawater thereby slowing down leaching. Increasing flow velocities led to higher leaching rates because the ABL thickness decreased from 1315 µm at 0 rpm shaking speed (no-flow conditions) to 38.4 µm at 125 rpm (turbulent conditions). Compared to salinity, turbulence had a more pronounced effect on leaching. Increasing the flow velocity led to a 35-fold decrease in the leaching rate, while increasing salinity led to a 2-fold increase. By calculating specific leaching times, that is, leaching half-lives (t1/2), time frames for leaching in different aquatic systems such as rivers and the ocean were determined. Given ABLD-limited leaching, DEHP is leached faster from PVC microplastics in rivers (t1/2 > 49 years) than in the ocean (t1/2 > 398 years). In both systems, PVC microplastics are a long-term source of phthalates.

Dechlorination and fuel gas generation in chemical looping conversion of waste PVC over inherently Na/Ca/K-containing bauxite residue-based oxygen carriers

The inert atmosphere in chemical looping (CL) technology can considerably inhibit the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans during the thermal treatment of polyvinyl chloride plastic (PVC) waste. In this study, PVC was innovatively converted to dechlorinated fuel gas via CL gasification under a high reaction temperature (RT) and the inert atmosphere by applying an unmodified bauxite residue (BR) as both a dechlorination agent and oxygen carrier. The dechlorination efficiency reached 49.98% at an oxygen ratio of only 0.1. Furthermore, a moderate RT (750 °C in this study) and an increased oxygen ratio enhanced the dechlorination effect. The highest dechlorination efficiency (92.12%) was achieved at an oxygen ratio of 0.6. Iron oxides in BR improved the generation of syngas from CL reactions. The yields of the effective gases (CH4, H2, and CO) increased by 57.13% to 0.121 Nm3/kg with an increase in oxygen ratio from 0 to 0.6. A high RT improved the production of the effective gases (an 809.39% increase to 0.344 Nm3/kg from 600 to 900 °C). Energy-dispersive spectroscopy and X-ray diffraction were used to study the mechanism, and formation of NaCl and Fe3O4 was observed on the reacted BR, indicating the successful adsorption of Cl and its capability as an oxygen carrier. Therefore, BR eliminated Cl in situ and enhanced the generation of value-added syngas, thereby achieving efficient PVC conversion.

Polyethylene and polyvinyl chloride microplastics promote soil nitrification and alter the composition of key nitrogen functional bacterial groups

Microplastics (MPs) contamination in soils seriously threatens agroecosystems globally. However, very few studies have been done on the effects of MPs on the soil nitrogen cycle and related functional microorganisms. To assess MP's impact on the soil nitrogen cycle and related functional bacteria, we carried out a one-month soil incubation experiment using typical acidic soil. The soil was amended with alfalfa meal and was spiked with 1% and 5% (mass percentage) of low-density polyethylene (LDPE) and polyvinyl chloride (PVC) MPs. Our results showed that both LDPE and PVC addition significantly increased soil nitrification rate and nitrate reductase activity, which could further promote soil denitrification. The relative abundance of diazotrophs, ammonium oxidizing, and denitrifying bacterial groups were significantly altered with MPs addition. Moreover, the MPs treatments greatly enhanced denitrifying bacteria richness. Redundancy analysis showed that nitrate reductase activity was the most significant factor affecting the soil functional bacterial community. Correlation analysis shows that Nitrosospira genus might be for the improvement of soil nitrification rate. Our results implied that MPs exposure could significantly affect the soil nitrogen cycling in farmland ecosystems by influencing essential nitrogen functional microorganisms and related enzymatic activities.

Fe3O4@Gum Arabic modified polyvinyl chloride membranes to improve antifouling performance and separation efficiency of organic pollutants

Nanofiltration (NF) membranes are promising media for water and wastewater treatment; however, they suffer from their hydrophobic nature and low permeability. For this reason, the polyvinyl chloride (PVC) NF membrane was modified by iron (III) oxide@Gum Arabic (Fe₃O₄@GA) nanocomposite. First, Fe₃O₄@GA nanocomposite was synthesized by the co-precipitation approach and then its morphology, elemental composition, thermal stability, and functional groups were characterized by various analyses. Next, the prepared nanocomposite was added to the casting solution of the PVC membrane. The bare and modified membranes were fabricated by a nonsolvent-induced phase separation (NIPS) method. The characteristics of fabricated membranes were assessed by mechanical strength, water contact angle, pore size, and porosity measurements. The optimum Fe₃O₄@GA/PVC membrane had a 52 L m^-2. h^-1. bar^-1 water flux with a high flux recovery ratio (FRR) value (82%). Also, the filtration experiment exhibited that the Fe₃O₄@GA/PVC membrane could remarkably remove organic contaminants, achieving high rejection rates of 98% Reactive Red-195, 95% Reactive Blue-19, and 96% Rifampicin antibiotic by 0.25 wt% of Fe₃O₄@GA/PVC membrane. According to the results, adding Fe₃O₄@GA green nanocomposite to the membrane casting solution is a suitable and efficient procedure for modifying NF membranes.

Enhanced migration of plasticizers from polyvinyl chloride consumer products through artificial sebum

In the present study, the migration of plasticizers from modeled and commercial polyvinyl chloride (mPVC and cPVC, respectively) to poly(dimethylsiloxane) via artificial sebum was assessed to mimic the dermal migration of plasticizers. In addition, the various factors affecting migration of phthalic acid esters (PAEs) from diverse PVC products were investigated. The migrated mass and migration ratio of PAEs increased but the migration rate decreased over time. The migration rate increased with sebum mass, contact time, and temperature but decreased under higher pressure. Low-molecular-weight PAEs (dimethyl phthalate and diethyl phthalate) migrated in higher amounts than high-molecular-weight PAEs (dicyclohexyl phthalate [DCHP] and diisononyl phthalate [DINP]). Diffusion of all PAEs in mPVC increased with temperature, with diffusion coefficients ranging from 10^-13 to 10^-15, 10^-12 to 10^-14, and 10^-10 to 10^-12 cm²·s^-1 at 25 °C, 40 °C, and 60 °C, respectively; the enthalpy of activation ranged between 127 and 194 kJ·mol^-1. Moreover, migration depended on total PAE content of the product, as the diffusion coefficient for DINP in cPVC (softer PVC) was approximately three orders of magnitude higher than that for DINP in mPVC (harder PVC); this may be due to the increase in free volume with increasing plasticizer content. Finally, the daily exposure doses of the plasticizers were estimated. These findings will be helpful for estimating dermal exposure risk.

larvae

The negative consequences of microplastics pollution on the health of aquatic species have garnered extensive attention. However, the mechanisms through which microplastics may cause harm in the reproductive processes of fish remain unknown. For this study, Cyprinus carpio var. was subjected to four treatments with various concentrations of PVC microplastics for 60 days, through food rationed diets (no plastic control, 10%, 20% and 30%). The gonadosomatic indices, gonad and brain histologies, sex hormone levels, and transcriptional and translational genes in the hypothalamic-pituitary-gonadal (HPG) axes of both sexes were observed. According to the results, the gonadosomatic indices were significantly decreased, gonadal development was delayed, and the level of estradiol (E2) in the females was significantly elevated. In addition, the expression levels of genes associated with the HPG axis in the brains and gonads (gnrh, gtha1, fshβ, cyp19b, erα, vtg1, dmrt1, sox9b, and cyp19a) and the transcription levels of apoptosis-related genes in the brains and gonads (caspase3, bax, and bcl-2) exhibited significant changes. Further investigation revealed that the translation levels of genes linked to sex differentiation and sex steroid hormone (cyp19b and dmrt1) were significantly altered. These findings indicated that PVC likely microplastics may have a negative impact on the reproductive system of Cyprinus carpio var. by inhibiting gonadal development, affecting the gonad and brain structures, and altering the levels of steroid hormones and the expression of HPG axis-related genes. This work provides new insights into the toxicity of microplastics in aquatic organisms by revealing that PVC microplastics are a potential threat against the reproduction of fish populations.

Influences of input concentration, media particle size, metal cation valence, and ionic concentration on the transport, long-term release, and particle breakage of polyvinyl chloride nanoplastics in saturated porous media

The environmental impact of nanoplastics has gradually attracted widespread attention; however, nanoplastics of polyvinyl chloride, one of the most commonly used plastics, have not yet been studied. In this study, we investigated the transport, long-term release behavior, and particle fracture of polyvinyl chloride nanoplastics (PVC NPs) in saturated quartz sand with different metal cations, ionic concentrations, input concentrations, and sand grain sizes by determining breakthrough, long-term release, and particle size distribution curves. The breakthrough curves and retention profiles were simulated by a mathematical model. The transport of PVC NPs increased with increased input concentration and sand grain size, which could be predicted by the Derjaguin-Landau-Verwey-Overbeek (DLVO) and colloid filtration theories. Increased ionic concentration and metal cation valence could restrain the transport of PVC NPs in saturated quartz sand owing to the decreased energy barrier between PVC NPs and sand grains. The total released amount of PVC NPs in the long-term release tests with different experimental conditions ranged from 3.91 to 21.95%. Increased sand grain size and decreased metal cation valence and ionic concentration resulted in an increased released amount of retained PVC NPs in saturated quartz sand, indicating increased release ability and mobility. The particle fracture results indicated that the PVC NPs were not broken down during long-term release under the experimental conditions of this research. This opens up a completely new and meaningful study of whether nanoplastics are broken down into smaller nanoplastics during their long-term release under various conditions.

Adsorption of 2-hydroxynaphthalene, naphthalene, phenanthrene, and pyrene by polyvinyl chloride microplastics in water and their bioaccessibility under in vitro human gastrointestinal system

The interaction of microplastics (MPs) and organic pollutants has recently become a focus of investigation. To understand how microplastic residues affect the migration of organic pollutants, it is necessary to examine the adsorption and desorption behavior of organic pollutants on MPs. In this study, integrated adsorption/desorption experiments and theoretical calculations were used to clarify the adsorption mechanism of 2-hydroxynaphthalene (2-OHN), naphthalene (NAP), phenanthrene (PHE), and pyrene (PYR) by polyvinyl chloride microplastics (PVC-MPs). Based on the phenomenological mathematical models, the rate-limiting step for analyte adsorption onto PVC-MPs was adsorption onto active sites (R² = 0.865-0.995). Except for PHE, analyte adsorption isotherms were well described by the Freundlich model (R² = 0.992-0.998), and adsorption thermodynamics showed that analyte adsorption on PVC-MPs was a spontaneous exothermic process (ΔH⁰ < 0; ΔG⁰ < 0). Based on the order of adsorption efficiency of 2-OHN < NAP < PHE < PYR, which is identical to the competitive adsorption experiment, polycyclic aromatic hydrocarbon (PAH) adsorption on PVC-MPs increased as the aromatic ring number increased and the hydroxyl content decreased. The release of 2-OHN (49 %-52 %) from PVC-MPs into the simulated gastrointestinal environment was greater than that of NAP (5.5 %-5.7 %). Theoretical calculations and adsorption tests indicated that hydrophobic interaction was the primary influence on the adsorption of PAHs and their hydroxylated derivatives by PVC-MPs. These findings improve our understanding of MPs' behavior and dangers as pollutant carriers in the aquatic environment and help us develop recommendations for the pollution control of MPs.

Understanding the aggregation, consumption, distribution and accumulation of nanoparticles of polyvinyl chloride and polymethyl methacrylate in Ruditapes philippinarum

Plastic products have become an integral part of our life. A widespread usage, high stability, uncontrolled disposal and slow degradation of plastics in the environment led to the generation and accumulation of nanoparticles of polymers (NPs) in the marine environment. However, little is known about the aggregation, consumption and distribution of NPs from common polymers such as polyvinyl chloride (NP-PVC) and polymethyl methacrylate (NP-PMMA) inside marine animal physiologies. In the current study, two types of polymers (PVC and PMMA) × four exposure concentrations (1, 5, 15 and 25 mg/L) × four times (4, 8, 12 and 24 h) exposure studies were conducted to understand the consumption and distribution of luminescent NP-PVC (98.6 ± 17.6 nm) and NP-PMMA (111.9 ± 37.1 nm) in R. philippinarum. Under laboratory conditions, NP-PVC showed a higher aggregation rate than NP-PMMA in seawater within a period of 24 h. Aggregations of NPs increased with an increase in initial NP concentrations, leading to significant settling of nanoparticles within 24 h exposure. Such aggregation and settling of particles enhanced the consumption of NPs by benthic filter-feeding R. philippinarum at all exposure concentrations during 4 h exposure. More interestingly, NP-PVC and NP-PMMA were observed in large amounts in both liver and gills (22.6 % - 29.1 %) of the clams. Furthermore, NP-PVC was detected in most organs of R. philippinarum as compared to NP-PMMA. This study demonstrates that different polymers distribute and accumulate differently in the same biological model under laboratory exposure conditions based on their chemical nature.

Phytotoxicity of microplastics to the floating plant Spirodela polyrhiza (L.): Plant functional traits and metabolomics

Freshwater ecosystems are gradually becoming sinks for terrestrial microplastics (MPs), posing a potential ecological risk. Although the effects of MPs on plankton and aquatic animals in freshwater ecosystems have been given increasing attention, the toxicity of MPs to the metabolism of aquatic plants remains unclear. Here, the model aquatic plant Spirodela polyrhiza (L.) Schleid. (S. polyrhiza) was exposed to polyvinyl chloride (PVC; 0, 10, 100 and 1000 mg/L) MPs, and changes in the plant functional traits and physiological metabolism were monitored. The results showed that the high dose of PVC MPs decreased the adventitious root elongation ratio by 41.68% and leaf multiplication ratio by 61.03% of S. polyrhiza, and resulted in the decrease in anthocyanin and nitrogen contents to 63.45% and 84.21% of the control group, respectively. Moreover, the widely targeted metabolomics analysis results showed 37 differential metabolites in the low-dose treatment and 119 differential metabolites in the high-dose treatment. PVC MPs interfered with organic matter accumulation by affecting carbon metabolism, nitrogen metabolism, amino acid metabolism and lipid metabolism, and S. polyrhiza resists PVC MP stress by regulating the synthesis and metabolism of secondary metabolites. PVC MPs had concentration-related toxicological effects on plant functional traits, inhibited plant growth and reproduction, affected plant nutrient metabolism, and exhibited profound effects on the nitrogen fate of aquatic plant habitats. Overall, we systematically summarized the metabolic response mechanisms of aquatic plants to PVC MP stress, providing a new perspective for studying the effects of MPs on plant trait function and ecological risks.