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1.
Sci Rep ; 14(1): 8863, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38632269

RESUMO

Ethylene vinyl acetate (EVA) copolymers are widely employed as pour point depressants to enhance the flow properties of crude oil. However, EVA copolymers have limitations that necessitate their development. This work investigated the modification of EVA via gamma radiation-induced grafting of butyl acrylate (BuA) monomers and the evaluation of grafted EVA as a pour point depressant for crude oil. The successful grafting of poly(butyl acrylate) p(BuA) onto EVA was verified through grafting parameters, FTIR spectroscopy, and 1H NMR spectroscopy. Treating crude oil with 3000 ppm of (EVA)0kGy, (EVA)50kGy, and (1EVA:3BuA)50kGy yielded substantial reductions in pour point of 24, 21, and 21 °C, respectively. Also, rheological characterization demonstrated improving evidenced by a viscosity reduction of 76.20%, 67.70%, and 71.94% at 25 °C, and 83.16%, 74.98%, and 81.53% at 12 °C. At low dosages of 1000 ppm, the EVA-g-p(BuA) exhibited superior pour point reductions compared to unmodified EVA, highlighting the benefit of incorporating p(BuA) side chains. The grafted EVA copolymers with p(BuA) side chains showed excellent potential as crude oil flow improvers by promoting more effective adsorption and co-crystallization with paraffin wax molecules.

2.
Drug Des Devel Ther ; 17: 2985-3021, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37789970

RESUMO

Introducing dental polymers has accelerated biotechnological research, advancing tissue engineering, biomaterials development, and drug delivery. Polymers have been utilized effectively in dentistry to build dentures and orthodontic equipment and are key components in the composition of numerous restorative materials. Furthermore, dental polymers have the potential to be employed for medication administration and tissue regeneration. To analyze the influence of polymer-based investigations on practical medical trials, it is required to evaluate the research undertaken in this sector. The present review aims to gather evidence on polymer applications in dental, oral, and maxillofacial reconstruction.


Assuntos
Materiais Biocompatíveis , Engenharia Tecidual , Materiais Biocompatíveis/farmacologia , Sistemas de Liberação de Medicamentos , Polímeros
3.
Sci Total Environ ; 852: 158446, 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36058336

RESUMO

Recent research is directed toward studying plastic pollution in rivers, and estuaries due to the importance of freshwater bodies in all aspects of life. The river deltas and estuaries are interesting for studying the flux of plastics into the oceans. The Nile River has been identified as a hot spot of plastic litter flux in the eastern Mediterranean basin. In addition, it was nicknamed "Plastic Nile", yet this major river is largely unexplored with a lack of field measurements and adequate surveys. The current study was based on bridging this scientific gap. Three trips were conducted, covering 30 km in the Rosetta branch and 23 km in the Damietta branch, during the high water level in summer 2021, and 10 km off the inlet of Lake Burullus, in spring 2021. Microplastics in surface water ranged from 761 ± 319 to 1718 ± 1008 MPs/m3, and from 167 ± 137 to 1630 ± 1303 MPs/kg of dry sediments. Land use/ land cover mapping using Sentinel-2 images showed several sources of pollution that contribute to plastic contamination in the study area. Thermal analysis indicated seven plastic polymers; including, PE, PP, PET, PEVA, and PTFE, using discarded plastic products as reference materials. Microplastics were composed of colored and glossy fragments of sizes <500 µm, originating from land-based sources. Pollution load, polymer risk assessment, and ecological risk indices were calculated. Based on field observations macro-plastics were retained within the extensive network of infrastructure and dam systems. 80-106 billion MPs/year were estimated to flux from the Nile estuaries into the Mediterranean Sea. The current situation urges the development of binding plans to reduce plastic waste in the Nile Delta, as well as setting environmental monitoring points along the Deltaic coast.


Assuntos
Microplásticos , Poluentes Químicos da Água , Plásticos/análise , Estuários , Prevalência , Poluentes Químicos da Água/análise , Monitoramento Ambiental/métodos , Lagos , Medição de Risco , Água/análise , Politetrafluoretileno , Mar Mediterrâneo
4.
Environ Pollut ; 313: 120044, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36064058

RESUMO

Plastic waste is a major threat to various marine ecosystems. Due to being semi-enclosed basin with dense population, the Mediterranean Sea has been considered as a hot spot for plastic pollution. Alexandria was listed as one of the major cities contributing to plastic waste in the eastern Mediterranean basin. Accordingly, microplastics (MPs) abundance and composition were investigated in the digestive tracts of commercial fish species from two major fishing areas in Alexandria; Abu-Qir Bay and Eastern Harbor, which are affected by plastic pollution. The incidence and average densities of MPs were 91.8 ± 8.4% and 11.7 ± 9.5 items fish-1, similar to highly polluted regions in the southeastern Mediterranean Sea. The average MPs concentration was significantly higher in Sparus aurata (38.3 ± 28.4 items fish-1) than all species, except for Siganus rivulatus and Boops boops. Polyethylene and poly ethylene-vinyl acetate were the dominant polymers in the fish digestive tracts. Four types of plastic polymers were recorded in Siganus rivulatus and five in Parupeneus macronemus. The dominance of glossy fragments (sizes <500 µm) in Abu-Qir Bay indicated land-based source of pollution from domestic, agricultural, and industrial wastes. The dominance of larger plastic filaments and colored fragments in the Eastern Harbor suggested secondary MPs, originating from the fragmentation of larger plastic items of sea-based sources, such as fishing and recreational activities.


Assuntos
Microplásticos , Poluentes Químicos da Água , Animais , Ecossistema , Egito , Monitoramento Ambiental , Etilenos , Resíduos Industriais , Mar Mediterrâneo , Plásticos , Polietilenos , Poluentes Químicos da Água/análise
5.
Bioorg Chem ; 127: 105972, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35728290

RESUMO

The popularity of nanogel as nano drug carrier lies in its adjustable physical properties, and the ability to encapsulate drug particles with improved properties is being developed to meet the diverse pH-sensitive nanogel for anticancer agent. Monitoring pH has been identified as an important diagnostic element during the treatment process. A pH-sensitive nanogel consisting of (PEG/PMAc) in the ratio of (50:50%) hasbeen cross-linkedby γ-irradiation techniques at an irradiation dose of 5 kGy. Compound 4 and its nanogel 5 were synthesized and assessed for their anticancer effects against HepG2, A549, MCF-7 and HCT-116 as dual VEGFR-2 and EGFR tyrosine kinases inhibitors. The molecular design was performed to investigate the binding mode of compound 4 with VEGFR-2 and EGFR receptors. Our compound 5 in nanogel showed enhanced anticancer activities against the four tested cancer cell lines and also showed higher inhibition activities against VEGFR-2 and EGFRT790M kinases than the derivative 4. Finally, our derivative 4 showed good in silico calculated ADMET profile. It was expected to show good GIT absorption in human, lower CNS side effects, no hepatotoxic actions and higher acute and oral chronic toxic doses in comparing to sorafenib and erlotinib. The obtained results showed that, our compound could be useful as a template for future design, optimization, adaptation and investigation to produce more potent and selective dual VEGFR-2/EGFRT790M inhibitors with higher anticancer activity.


Assuntos
Antineoplásicos , Neoplasias Pulmonares , Acrilatos , Antineoplásicos/química , Proliferação de Células , Sistemas de Liberação de Medicamentos , Desenho de Fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Receptores ErbB , Etilenoglicol/farmacologia , Humanos , Concentração de Íons de Hidrogênio , Simulação de Acoplamento Molecular , Mutação , Nanogéis , Inibidores de Proteínas Quinases/química , Relação Estrutura-Atividade , Receptor 2 de Fatores de Crescimento do Endotélio Vascular
6.
J Environ Manage ; 210: 307-315, 2018 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-29358125

RESUMO

A new in-situ cationic polymerization was performed to synthesize a cross-linked (91%) polystyrene (PS) organogel through tetrachloroethylene radiolysis assisted by 60Co gamma rays. Hoernschemeyer diagram and swelling capacity test show a better selectivity of PS organogel to chlorinated molecules compared to ester, hydrocarbons and alcohols organic molecules by 80-184 folds. Response surface modeling (RSM) of CPs (2,4,6-trichlorophenol) sorption from artificial wastewater confirm superiority of PS organogel to absorb 1746 µmol CPs/g (∼345 mg CPs/g) at broad pH (4-10) and temperature (25-45 °C). Based on ANOVA statistic, simulated CPs absorption model onto PS organogel was successfully developed, with accuracy of prediction of R2≈ RAdj2 of 0.991-0.995 and lower coefficient of variation of 2.73% with Fmodel of 611.4 at p < .0001. Particularly, the usage of PS organogel for petroleum wastewater reclamation exhibited higher absorption affinities for all the organic contaminants especially for CPs (>99%) by non-covalent and/or dispersive interaction mechanisms with a well-term reusability and good stability up to 5 cycles.


Assuntos
Poliestirenos/química , Purificação da Água , Cátions , Clorofenóis , Resíduos Industriais , Indústria de Petróleo e Gás , Polimerização , Águas Residuárias
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