RESUMO
Objective: To investigate the biological safety of commercially available natural rubber latex and synthetic polyurethane condoms. Methods: Natural rubber latex condom brands of A1 and A2 and polyurethane condom brands of B1 and B2 were purchased from large chain pharmacies in Chengdu, with three packages randomly selected for each brand. The study assessed the toxic effects of condom extracts on L-929 mouse fibroblasts according to GB/T standards. Gross observation and histopathological evaluation were conducted to assess the irritation reactions of condoms on the vagina and penis of rabbits (3 rabbits were used for each brand), as well as their sensitization effects on guinea pig skin. Additionally, the impact of continuous perfusion of condom extracts of the vaginas of SD rats for 30 days on their reproductive systems was evaluated, following GB/T standards (5 rats were used for each brand). Results: Extracts from natural rubber latex condom brands A1 and A2, at concentrations of 100% and 50%, exhibited significant cytotoxicity, with optical density (OD) values being significantly lower than those of the blank control group and the polyurethane condom brands B1 and B2 (P<0.01). There was no significant difference in cell morphology and OD values between the extracts of B1 and B2 and the blank control group (P>0.05). Vaginal congestion was found in 3 rabbits from A1 group and 1 rabbit from the A2 group, while no obvious congestion was noted in rabbits from the B1 and the B2 groups. Histopathological examination showed scattered inflammatory cell infiltration in the vaginal tissue of 3 rabbits from the A1 group and 2 rabbits from the A2 group, and slight congestion in the blood vessels of the lamina propria. No obvious pathological changes were observed in the vaginal tissue of polyurethane brand rabbits. Two rabbits from the A1 group and 1 rabbit from the A2 group showed transient and mild erythema on the penis during the experiment. Histopathological examination showed that 1 rabbit from A1 group had small foci of pericapillary lymphocytes in the dermis of the penis, while no significant pathological changes were observed in the penile tissue of A2, B1, and B2 groups. After 30 days of continuous vaginal perfusion with condom extract, 3 rats in A1 group and 2 rats in the A2 group had uterine congestion, with the degree of congestion being lower in the A2 group. No significant congestion or pathological changes were observed in the vaginal and penile tissues of rabbits, or in the uterine tissues of rats from the polyurethane groups. None of the 4 groups of guinea pigs showed significant skin allergic reactions to the condom extracts. Conclusion: Significant differences in biosafety exist among condoms of various materials and brands. To ensure product safety, it is crucial to strengthen quality control and regulatory oversight after condoms become commercially available.
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Preservativos , Látex , Poliuretanos , Ratos Sprague-Dawley , Animais , Coelhos , Feminino , Cobaias , Ratos , Masculino , Látex/química , Camundongos , Vagina/patologia , Fibroblastos/efeitos dos fármacos , Teste de Materiais , Borracha/efeitos adversosRESUMO
Endoscopic submucosal dissection (ESD) of fibrotic colorectal lesions is difficult and has a high complication rate. There are only a few reports on the utility of orthodontic rubber band (ORB) traction in reducing the difficulty of this procedure. This study aimed to investigate the risk factors for perforation when applying ORB traction during ESD of fibrotic colorectal lesions. We continuously collected the clinical data of 119 patients with fibrotic colorectal lesions who underwent ESD with ORB and clip traction between January 2019 and January 2024. Possible risk factors for perforation were analyzed. The median ORB-ESD operative time was 40 (IQR 28-62) min, and the en bloc and R0 resection rates were 94.1% and 84.0%, respectively. Perforation occurred in 16 of 119 patients (13.4%). The lesion size, lesion at the right half of the colon or across an intestinal plica, the degree of fibrosis, operation time, and the surgeon's experience were associated with perforation during ORB-ESD (P < 0.05). Multivariate logistic regression analysis showed that lesions in the right colon (OR 9.027; 95% CI 1.807-45.098; P = 0.007) and those across an intestinal plica (OR 7.771; 95% CI 1.298-46.536; P = 0.025) were independent risk factors for perforation during ORB-ESD. ORB-ESD is an effective and feasible approach to treat fibrotic colorectal lesions. Adequate preoperative evaluation is required for lesions in the right colon and across intestinal plicas to mitigate the risk of perforation.
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Neoplasias Colorretais , Ressecção Endoscópica de Mucosa , Humanos , Feminino , Masculino , Ressecção Endoscópica de Mucosa/efeitos adversos , Ressecção Endoscópica de Mucosa/métodos , Neoplasias Colorretais/cirurgia , Neoplasias Colorretais/patologia , Pessoa de Meia-Idade , Idoso , Fatores de Risco , Fibrose , Perfuração Intestinal/etiologia , Perfuração Intestinal/cirurgia , Colo/cirurgia , Colo/patologia , Colo/lesões , Estudos Retrospectivos , Borracha , Aparelhos Ortodônticos/efeitos adversos , Duração da CirurgiaRESUMO
The para rubber tree (Hevea brasiliensis) is the world's sole commercial source of natural rubber, a vital industrial raw material. However, the narrow genetic diversity of this crop poses challenges for rubber breeding. Here, we generate high-quality de novo genome assemblies for three H. brasiliensis cultivars, two H. brasiliensis wild accessions, and three other Hevea species (H. nitida, H. pauciflora, and H. benthamiana). Through analyzing genomes of 94 Hevea accessions, we identify five distinct lineages that do not align with their previous species delineations. We discover multiple accessions with hybrid origins between these lineages, indicating incomplete reproductive isolation between them. Only two out of four wild lineages have been introduced to commercial rubber cultivars. Furthermore, we reveal that the rubber production traits emerged following the development of a large REF/SRPP gene cluster and its functional specialization in rubber-producing laticifers within this genus. These findings would enhance rubber breeding and benefit research communities.
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Genoma de Planta , Hevea , Filogenia , Borracha , Hevea/genética , Borracha/metabolismo , Melhoramento Vegetal , Variação Genética , Evolução Molecular , Família MultigênicaRESUMO
INTRODUCTION: The article examines the experiences of protesters and bystanders who have sustained eye injuries from rubber bullets fired by the police. Use of rubber bullets by police officers during public protests is officially regulated, but there is insufficient documentation about the nature of fatal and non-fatal injuries linked to rubber bullet use during protests in South Africa. METHODS: We pres-ent three case studies based on data gathered from student protests, community protests, and media reports. Through the analysis of these sources, the article presents the personal stories of individuals who have experienced eye injuries, detailing how the incidents occurred and the subsequent impact on their lives. It also examines the accessibility of medical, psychological, and legal services available to victims in addressing the consequences of these injuries. RESULTS: The cases studies illustrate that rubber bullets were used frequently and often without due caution by police officers during the events examined. The use of rubber bullets was linked to numerous eye injuries, resulting in lasting psycho-logical and physical consequences for those affected. DISCUSSION: Rubber bullet-related eye injuries during protests are disturbingly common in South Africa. Consequently, there is an urgent need to provide essential services and support to those who suffer from these life-altering incidents.
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Traumatismos Oculares , Borracha , Humanos , África do Sul , Masculino , Adulto , Ferimentos por Arma de Fogo , Polícia , FemininoRESUMO
My name is Carles Guillot and I am 52 years old. On 17 July 2001, 23 years ago now, during a protest against the illegal as-sault and eviction of a squatted house, the Kasa de la Muntan-ya, a national police officer shot me point-blank in the face and permanently damaged my right eyeball. As the neighbourhood was taken over by the police, we had to wait a few hours before we could go to a hospital. Finally, some colleagues took me to the Bellvitge Hospital, the furthest hospital in the area, to avoid being identified by the police. The prognosis was clear: I would be one-eyed for life.The first days and weeks were very hard. Pain, headaches, and anger, a lot of anger.
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Sobreviventes , Humanos , Sobreviventes/psicologia , Pessoa de Meia-Idade , Masculino , Ferimentos por Arma de Fogo , Borracha , Tortura/psicologia , Traumatismos OcularesRESUMO
INTRODUCTION: Rubber bullets are projectiles whose use is potentially lethal. Between 1976 and 2017, they have caused at least 23 deaths and dozens of injuries in Spain, many of them serious, with loss of sight being the main type. In the period 2000 - 2020 alone, more than 40 people have been affected. METHODS: We review the legal framework, human impacts that go far beyond statistics and medical and psychosocial approaches. RESULTS: The paper focuses on key learnings in survivors' organisation, the process towards the prohibition of these weapons and strategic litigation, forensic documenta-tion and political advocacy.
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Borracha , Tortura , Humanos , Espanha , Ferimentos por Arma de FogoRESUMO
First responder professionals are at high risk for work-related injuries (e.g., extreme temperatures, chemical and biological threats); boots are essential to ensure body protection since they have full contact with the ground in all scenarios. A substantial body of work has investigated the necessity of improvements in protective boots, but there is limited research conducted on boots with fit-adjustable fasteners for secure and adjustable fit within this context. Thus, this study explored the areas for improvement in boot design for the development of form-fitting and yet comfortable boots focusing on two different boot designs, prototype all-hazards tactical boots (lace-up) and rubber boots (slip-on). Findings indicated that the boot design should address participants' concerns with the material choices of boots, specifically with bulkiness, weight, and flexibility. Our findings provide insights into boot material and design choices to improve protective boots for first responders.
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Desenho de Equipamento , Substâncias Perigosas , Sapatos , Humanos , Masculino , Adulto , Feminino , Socorristas , Traumatismos Ocupacionais/prevenção & controle , Roupa de Proteção , Borracha , Pessoa de Meia-IdadeRESUMO
Natural rubber (NR) and its derivatives play indispensable roles in various industries due to their unique properties and versatile applications. However, the widespread utilization of NR faces intrinsic challenges such as limited mechanical strength, poor resistance to heat and organic solvent, poor electrical conductivity, and low compatibility with other materials, prompting researchers to explore enhancing its performance. Modified NRs (MNRs) like cyclization, deproteinization, chlorination, epoxidation, or grafting NR demonstrated a few enhanced merits compared to NR. However, various strategies, such as blending, vulcanization, crosslinking, grafting, plasticization, reinforcement, and nanostructuring, overcame most drawbacks. This review comprehensively examines these challenges and delves into the modification strategies employed to enhance the properties and expand the applications of NR and its derivatives. Furthermore, the review explores future visions for the NR industry, emphasizing integrating advanced modification techniques, adopting sustainable practices, and promoting circular economy principles. By elucidating the inherent challenges, outlining effective modification strategies, and envisioning future trajectories, this review provides valuable insights for stakeholders seeking to navigate and contribute to the sustainable development of the NR sector.
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Borracha , Borracha/químicaRESUMO
The research investigates the effects of substituting sand with rubber particles derived from waste tyres-up to 40% by volume-and the inclusion of polypropylene (PP) fibres. Unlike steel fibres, which can cause operational challenges and surface irregularities in the printing process, PP fibres' flexibility integrates well within the concrete matrix. This integration ensures smooth extrusion and a high-quality surface finish, enhancing the printability of the concrete. The study's findings reveal that including rubber particles and PP fibres impacts the concrete's properties, showing a general decline in compressive and flexural strengths as the rubber content increases. Nevertheless, the PP fibre-enhanced mixtures maintain sufficient structural strength, demonstrating an anisotropic compressive strength above 30 MPa and a flexural strength of 4 MPa. These results underscore the feasibility of using rubberised 3D-printed concrete with PP fibres in sustainable construction practices, aligning with standards (ACI 318:2018) and contributing to eco-friendly and innovative construction methodologies.
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Materiais de Construção , Polipropilenos , Impressão Tridimensional , Borracha , Borracha/química , Polipropilenos/química , Anisotropia , Teste de Materiais , Força CompressivaRESUMO
Forest restoration is an effective method for restoring degraded soil ecosystems (e.g., converting primary tropical forests into rubber monoculture plantations; RM). The effects of forest restoration on microbial community diversity and composition have been extensively studied. However, how rubber plantation-based forest restoration reshapes soil microbial communities, networks, and inner assembly mechanisms remains unclear. Here, we explored the effects of jungle rubber mixed (JRM; secondary succession and natural restoration of RM) plantation and introduction of rainforest species (AR; anthropogenic restoration established by mimicking the understory and overstory tree species of native rainforests) to RM stands on soil physico-chemical properties and microbial communities. We found that converting tropical rainforest (RF) to RM decreased soil fertility and simplified microbial composition and co-occurrence patterns, whereas the conversion of RM to JRM and AR exhibited opposite results. These changes were significantly correlated with pH, soil moisture content (SMC), and soil nutrients, suggesting that vegetation restoration can provide a favorable soil microenvironment that promotes the development of soil microorganisms. The complexity and stability of the bacterial-fungal cross-kingdom, bacterial, and fungal networks increased with JRM and AR. Bacterial community assembly was primarily governed by stochastic (78.79 %) and deterministic (59.09 %) processes in JRM and AR, respectively, whereas stochastic processes (limited dispersion) predominantly shaped fungal assembly across all forest stands. AR has more significant benefits than JRM, such as a relatively slower and natural vegetation succession with more nutritive soil conditions, microbial diversity, and complex and stable microbial networks. These results highlight the importance of sustainable forest management to restore soil biodiversity and ecosystem functions after extensive soil degradation and suggest that anthropogenic restoration can more effectively improve soil quality and microbial communities than natural restoration in degraded rubber plantations.
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Microbiota , Microbiologia do Solo , Borracha , Solo/química , Hevea , Floresta Úmida , Recuperação e Remediação Ambiental/métodos , Fungos , Bactérias , FlorestasRESUMO
Tire wear particles (TWPs) are considered an important component of microplastic pollution in the marine environment and occur together with a variety of aquatic pollutants, including frequently detected bisphenols. The adverse effects of TWPs or bisphenols on aquatic organisms have been widely reported. However, the combined toxicity of TWPs and bisphenols is still unknown. In this study, the combined toxicity of both pristine (p-) and aged TWPs (a-TWPs) and four bisphenols ((bisphenol A (BPA), bisphenol F (BPF), bisphenol S (BPS), and bisphenol AF (BPAF)) to Tigriopus japonicus was evaluated. TWPs increased the toxicity of BPA and BPF but decreased the toxicity of BPAF. For BPS, there was synergistic toxic effect in the presence of p-TWPs, but slightly antagonistic effect was observed in the presence of a-TWPs. This adsorption of BPAF by TWPs resulted in a reduction of its toxicity to the copepod. A-TWPs could release more Zn than p-TWPs, and the released Zn contributed to the synergistic effect of TWPs and BPA or BPF. The aggregation formed by TWPs in certain sizes (e.g., 90-110 µm) could cause intestinal damage and lipid peroxidation in T. japonicus. The synergistic effect of p-TWPs and BPS might be due to the aggregation size of the binary mixture. The results of the current study will be important to understand the combined toxic effect of TWPs and bisphenols and the potential toxic mechanisms of the binary mixture.
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Compostos Benzidrílicos , Copépodes , Fenóis , Poluentes Químicos da Água , Fenóis/toxicidade , Animais , Compostos Benzidrílicos/toxicidade , Poluentes Químicos da Água/toxicidade , Copépodes/efeitos dos fármacos , Microplásticos/toxicidade , Borracha/toxicidade , Borracha/química , Sulfonas/toxicidadeRESUMO
A diaphragm pump is a type of volumetric pump that has excellent sealing performance. An electromagnetic diaphragm pump is a kind of widely adopted diaphragm pump that has a simple structure, low power loss, and high cost performance. However, the calculation method of deformation for the electromagnetic diaphragm pump rubber diaphragm is presently lacking. Herein, a calculating method of deformation for the electromagnetic diaphragm pump rubber diaphragm is proposed. By establishing and analyzing a deformation model of the electromagnetic diaphragm pump rubber diaphragm, a theoretical relationship between the deformation of the electromagnetic diaphragm pump rubber diaphragm, the size of the electromagnetic diaphragm pump rubber diaphragm and the pressure of fluid is determined. The experimental results indicate that the biggest difference between the tested axial deformation and the calculated axial deformation of the electromagnetic diaphragm pump rubber diaphragm is 0.04 mm and the calculation results show agreement with the experimental results.
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Fenômenos Eletromagnéticos , Borracha , Borracha/química , Desenho de Equipamento , Modelos TeóricosRESUMO
Eucommia ulmoides is a temperate gum source plant that produces trans-polyisoprene (TPI), also known as Eucommia rubber. The structural configuration and function of TPI offer a new material with important potential for industrial development. In this study, we detected the TPI content in the leaves of diploid and triploid E. ulmoides plants. The average TPI content in the leaves of triploid E. ulmoides was significantly higher than that of diploid. Transcriptome data and weighted gene co-expression network analyses identified a significant positive correlation between the EuFPS1 gene and TPI content. Overexpression of EuFPS1 increased the density of rubber particles and TPI content, indicating its crucial role in TPI biosynthesis. In addition, the expression of EuHDZ25 in E. ulmoides was significantly positively correlated with EuFPS1 expression. Yeast one-hybrid and dual-luciferase assays demonstrated that EuHDZ25 mainly promotes TPI biosynthesis through positive regulation of EuFPS1 expression. The significantly up-regulated expression of EuHDZ25 and its consequent upregulation of EuFPS1 during the biosynthesis of TPI may partially explain the increased TPI content of triploids. This study provides an important theoretical foundation for further exploring the molecular mechanism of secondary metabolites content variation in polyploids and can help to promote the development and utilization of rubber resources.
Assuntos
Eucommiaceae , Regulação da Expressão Gênica de Plantas , Folhas de Planta , Proteínas de Plantas , Borracha , Eucommiaceae/genética , Eucommiaceae/metabolismo , Eucommiaceae/química , Borracha/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Hemiterpenos/biossíntese , Hemiterpenos/metabolismoRESUMO
This study investigates the incorporation of block natural rubber (NR) as a viscosity-inducing agent in NR oily liquids designed for drug delivery systems. A variety of liquids, encompassing natural oils, synthetic and non-oil liquids, and a eutectic mixture, were incorporated with NR using solvent displacement technique. Successful formulations were achieved for several oily liquids, with viscosity correlating to NR concentration. Particularly, a eutectic mixture of menthol and camphor exhibited optimal viscosity by direct dissolving enabling the development of transdermal ibuprofen delivery and injectable azithromycin for periodontitis treatment. NR prolonged the release of both drugs. The extended-release ibuprofen system holds promise for transdermal applications, while the azithromycin system displayed inhibitory effects against Staphylococcus aureus, Streptococcus mutans, and Porphyromonas gingivalis, suggesting potential for periodontitis treatment. Overall, this investigation advances the development of NR oily liquids as a versatile drug delivery system that can be applied both on the skin and for the local injection into the periodontal pocket, showcasing promise for various therapeutic applications.
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Administração Cutânea , Sistemas de Liberação de Medicamentos , Borracha , Borracha/química , Viscosidade , Bolsa Periodontal/tratamento farmacológico , Bolsa Periodontal/microbiologia , Liberação Controlada de Fármacos , Ibuprofeno/administração & dosagem , Ibuprofeno/química , Ibuprofeno/farmacologia , Azitromicina/administração & dosagem , Humanos , Animais , Staphylococcus aureus/efeitos dos fármacos , Antibacterianos/administração & dosagem , Antibacterianos/farmacologia , Antibacterianos/química , Periodontite/tratamento farmacológico , Periodontite/microbiologiaRESUMO
Solar steam generation (SSG) offers a sustainable approach to fresh water production. Herein, a novel dual-functional natural rubber/carbon black composite foam evaporator is presented for a cost-efficient SSG system that both produces fresh water and eliminates heavy metals present in the water. The composite foam is produced using the Dunlop process, and in its optimized form, it absorbed >96 % of sunlight. The foam evaporator exhibited a thermal conductivity of 0.052 W/mâ K, a water evaporation rate of 1.40 kg/m2/h, converted 83.38 % of light to heat under 1 sun irradiation, and showed outstanding stability. The technology required to produce this composite foam is already available to make large-scale production feasible, while the natural raw materials are abundant. On the basis of its performance qualities, the rubber foam composite appears to be an excellent candidate for application as a viable solar absorber for SSG to produce fresh, clean water for commercial purposes.
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Metais Pesados , Borracha , Luz Solar , Borracha/química , Metais Pesados/química , Látex/química , Purificação da Água/métodos , Água/química , Descontaminação/métodos , Vapor , Poluentes Químicos da Água/química , Fuligem/químicaRESUMO
The blend of butadiene and acrylonitrile copolymer (NBR) with natural poly-cis-isoprene (NR) shows increased resistance to swelling in solvents in comparison to the individual components. In aerospace, NBR rubber is used as thermal protection for rockets and shall not contain other polymers, even in low contents, otherwise, it can affect the protection performance and rocket safety by causing detachment of the elastomer/propellant interface; therefore, this investigation presents methodologies to determine the NR/NBR contents. This study explores different analytical techniques, such as Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy, in the mid-infrared (MIR) by reflection and in the near-infrared by reflectance (NIRA) modes, Furthermore, quantification strategies by univariate, bivariate and multivariate (chemometric) models are evaluated and compared. A proposed methodology, based on multivariate Raman microscopy with partial least squares regression (PLS), showed high linearity (R2 > 0.99) and low error (< 0.82 %). The validation of FT-MIR data for the CH3, which presented lower error (1.3%) than vinylidene band (6%), showed that both methodologies (reflection and NIRA reflectance) can be used for the quantification of NR in NR/NBR. These results constitute a contribution to the state of the art in researching industrial and aerospace elastomeric applications.
Assuntos
Borracha , Análise Espectral Raman , Análise Espectral Raman/métodos , Borracha/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Butadienos/química , Butadienos/análiseRESUMO
In this study, a magnetic three-dimensional nano-composite based on Rubber-Fe3O4@Ni-Co Layered double hydroxide derived from ZIF-67 template was synthesized by a hydrothermal method. The proposed nano-composite was used as a sorbent for the enrichment of trace amounts of anti-cancer drugs (dasatinib and erlotinib hydrochloride) from plasma samples followed by determination using high-performance liquid chromatographic analysis (HPLC-UV). The synthesized nano-sorbent was characterized by X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, vibrating-sample magnetometer, Brunauer-Emmett-Teller surface analysis, Barrett-Joyner-Halenda pore size analysis and energy dispersive X-ray spectroscopy. Under optimal experimental conditions, factors affecting on extraction efficiency such as pH, ionic strength, extraction temperature and time, desorption solvent and time, the limit of detection (LODs) and the limit of quantification (LOQs) were obtained as 0.6, 2 µg/L for both of dasatinib and erlotinib, respectively. Also, linear range of the method were 2-500 and 2-1000 µg/L for dasatinib and erlotinib, respectively. Relative standard deviations (RSD%) for the repeatability of extraction on sorbent to sorbent were obtained as 3.59, 1.97 %, and one sorbent reusability were investigated and relative standard deviation values were obtained 5.35, 3.30 % for dasatinib and erlotinib, respectively.
Assuntos
Antineoplásicos , Cloridrato de Erlotinib , Limite de Detecção , Borracha , Borracha/química , Antineoplásicos/sangue , Antineoplásicos/química , Cromatografia Líquida de Alta Pressão/métodos , Reprodutibilidade dos Testes , Humanos , Cloridrato de Erlotinib/sangue , Cloridrato de Erlotinib/química , Modelos Lineares , Dasatinibe/sangue , Dasatinibe/química , Hidróxidos/química , Imidazóis/química , Imidazóis/sangue , Adsorção , Extração em Fase Sólida/métodos , Cobalto/química , Cobalto/sangue , Nanoestruturas/química , ZeolitasRESUMO
A superabsorbent hydrogel was prepared by the free-radical copolymerization of natural rubber (NR) latex with poly(acrylic acid) (PAA) at NR loadings up to 50 wt%. An NR/PAA hydrogel containing 40 wt% of NR (NR-40) had a water absorption capacity of 214 g/g (21,400 %) of its dry weight. The compressive modulus increased 512 % and sample integrity was improved due to the physical entanglement of NR chains. NR-40 hydrogel removed 97 % of methylene blue (MB) from the aqueous solution in 1 h (at initial concentrations of 10-1000 mg/L) and produced a maximum removal of 1191 mg MB/g of hydrogel at an initial MB concentration of 4500 mg/L. The adsorption of MB was an endothermic process. Fourier transform infrared spectroscopy indicated that hydrogen bonding and electrostatic interaction drove the process. After the in-situ incorporation of ZnO into NR-40, absorbed energy from sunlight generated active species that could photocatalytically degrade adsorbed MB in the hydrogel matrix. The scavenger tests indicated that superoxide radical anions and hydroxyl radicals were the main species for this process. The hydrogel composite material showed good stability and could be regenerated and reused over 10 cycles, degrading >80 % of the adsorbed dye. This novel natural-based hydrogel provides double functions of adsorption and photodegradation of toxic dyes without the requirement of chemicals and a separation process.
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Hidrogéis , Azul de Metileno , Óxido de Zinco , Azul de Metileno/química , Óxido de Zinco/química , Hidrogéis/química , Adsorção , Borracha/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação , Catálise , Purificação da Água/métodos , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
Rubber-derived chemicals (RDCs) originating from tire and road wear particles are transported into road stormwater runoff, potentially threatening organisms in receiving watersheds. However, there is a lack of knowledge on time variation of novel RDCs in runoff, limiting initial rainwater treatment and subsequent rainwater resource utilization. In this study, we investigated the levels and time-concentration profiles of 35 target RDCs in road stormwater runoff from eight functional areas in the Greater Bay Area, South China. The results showed that the total concentrations of RDCs were the highest on the expressway compared with other seven functional areas. N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), 6PPD-quinone, benzothiazole, and 1,3-diphenylguanidine were the top four highlighted RDCs (ND-228840 ng/L). Seasonal and spatial differences revealed higher RDC concentrations in the dry season as well as in less-developed regions. A lag effect of reaching RDC peak concentrations in road stormwater runoff was revealed, with a lag time of 10-90 min on expressways. Small-intensity rainfall triggers greater contamination of rubber-derived chemicals in road stormwater runoff. Environmental risk assessment indicated that 35% of the RDCs posed a high risk, especially PPD-quinones (risk quotient up to 2663). Our findings contribute to a better understanding of managing road stormwater runoff for RDC pollution.
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Chuva , Borracha , Cidades , Poluentes Químicos da Água/análise , Monitoramento Ambiental , ChinaRESUMO
To enhance tire durability, the antioxidant N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) is used in rubber, but it converts into the toxic 6PPD quinone (6PPD-Q) when exposed to oxidants like ozone (O3), causing ecological concerns. This review synthesizes the existing data to assess the transformation, bioavailability, and potential hazards of two tire-derived pollutants 6PPD and 6PPD-Q. The comparative analysis of different thermal methods utilized in repurposing waste materials like tires and plastics into valuable products are analyzed. These methods shed light on the aspects of pyrolysis and catalytic conversion processes, providing valuable perspectives into optimizing the waste valorization and mitigating environmental impacts. Furthermore, we have examined the bioavailability and potential hazards of chemicals used in tire manufacturing, based on the literature included in this review. The bioavailability of these chemicals, particularly the transformation of 6PPD to 6PPD-Q, poses significant ecological risks. 6PPD-Q is highly bioavailable in aquatic environments, indicating its potential for widespread ecological harm. The persistence and mobility of 6PPD-Q in the environment, along with its toxicological effects, highlight the critical need for ongoing monitoring and the development of effective mitigation strategies to reduce its impact on both human health and ecosystem. Future research should focus on understanding the chronic effects of low-level exposure to these compounds on both terrestrial and aquatic ecosystems, as well as the potential for bioaccumulation in the food chain. Additionally, this review outlines the knowledge gaps, recommending further research into the toxicity of tire-derived pollutants in organisms and the health implications for humans and ecosystems.