Search results for "PLASTICS"
showing 10 items of 2724 documents
Titanium (IV) chloride complexes with salen ligands supported on magnesium carrier: Synthesis and use in ethylene polymerization
2009
The magnesium support with the formula MgCl 2 (THF) 0.32 (Et 2 AlCl) 0.36 was used for immobilization of salen complexes of titanium [Ti(salen)Cl 2 , Ti(salen(O-Me) 2 )Cl 2 ]. The effects of the catalyst composition (i.e. type of titanium complex and type of activator), polymerization temperature, polymerization time, and the effect of comonomer (1-octene) on the activity of the obtained supported catalysts, on the polymer characteristics (molecular weight, molecular weight distribution, melting point), and on the polymer morphology were studied. The findings were compared to those obtained for corresponding unsupported systems. Catalysts immobilization results in considerable changes in ca…
Preparation of Polymeric Nanoparticles by Photo-Crosslinking of an Acryloylated Polyaspartamide in w/o Microemulsion
2004
Biodegradable polymeric nanoparticles have been prepared by UV irradiation of an acryloylated water soluble polymer by an inverse microemulsion. The starting polymer was a α,β‐poly(N‐2‐hydroxyethyl)‐D,L‐aspartamide (PHEA) partially functionalized with glycidyl methacrylate (GMA) in order to introduce reactive vinyl groups in the side chain. The PHEA‐GMA copolymer obtained (PHG) was crosslinked by UV irradiation of the inverse microemulsion prepared by mixing an aqueous solution of PHG with propylene carbonate (PC)/ethyl acetate (EtOAc) in the presence of sorbitan trioleate (SPAN 85) as surfactant. Nanoparticles obtained were characterized by FTIR spectrophotometry, transmission electron mic…
Halloysite Nanotubes Coated by Chitosan for the Controlled Release of Khellin
2020
In this work, we have developed a novel strategy to prepare hybrid nanostructures with controlled release properties towards khellin by exploiting the electrostatic interactions between chitosan and halloysite nanotubes (HNT). Firstly, khellin was loaded into the HNT lumen by the vacuum-assisted procedure. The drug confinement within the halloysite cavity has been proved by water contact angle experiments on the HNT/khellin tablets. Therefore, the loaded nanotubes were coated with chitosan as a consequence of the attractions between the cationic biopolymer and the halloysite outer surface, which is negatively charged in a wide pH range. The effect of the ionic strength of the aqueous medium…
The Form is Not a Proper Part in Aristotle’s Metaphysics Z.17, 1041b11–33
2018
When Aristotle argues at the 'Metaphysics' Z.17, 1041b11–33 that a whole, which is not a heap, contains ‘something else’, i.e. the form, besides the elements, it is not clear whether or not the form is a proper part of the whole. I defend the claim that the form is not a proper part within the context of the relevant passage, since the whole is divided into elements, not into elements and the form. Different divisions determine different senses of ‘part’, and thus the form is not a part in the same sense as the elements are parts. I object to Koslicki’s (2006) interpretation, according to which the form is a proper part along the elements in a single sense of ‘part’, although she insists th…
Assessment of microplastics and other contaminants in marine vertebrates from the Western Mediterranean Sea
2023
Mediterranean marine biodiversity is under threat by pollution. For this reason, the main objective of this thesis was to analyse the presence of pollutants of concern in Mediterranean marine species. These studies are located in the Valencian Community (Spain), where we find loggerhead turtles, striped dolphins, and jewel lanternfish. Hence, we: 1. Analysed pesticides, heavy metals and phthalates in tissues of loggerhead turtles. 2. Studied microdebris present in beaches that are sporadically used as nesting grounds by loggerhead turtles. 3. Analysed striped dolphins# exposure to microplastics. 4. Quantified jewel lanternfish exposure to microplastics and tested their role as bioindicators…
Systematic Study of a Library of PDMAEMA-Based, Superparamagnetic Nano-Stars for the Transfection of CHO-K1 Cells.
2017
The introduction of the DNA into mammalian cells remains a challenge in gene delivery, particularly in vivo. Viral vectors are unmatched in their efficiency for gene delivery, but may trigger immune responses and cause severe side-reactions. Non-viral vectors are much less efficient. Recently, our group has suggested that a star-shaped structure improves and even transforms the gene delivery capability of synthetic polycations. In this contribution, this effect was systematically studied using a library of highly homogeneous, paramagnetic nano-star polycations with varied arm lengths and grafting densities. Gene delivery was conducted in CHO-K1 cells, using a plasmid encoding a green fluore…
A Biodegradable, Bio-Based Polymer for the Production of Tools for Aquaculture: Processing, Properties and Biodegradation in Sea Water
2023
Bio-based, biodegradable polymers can dramatically reduce the carbon dioxide released into the environment by substituting fossil-derived polymers in some applications. In this work, prototypes of trays for aquaculture applications were produced via injection molding by using a biodegradable polymer, Mater-Bi®. A characterization carried out via calorimetric, rheological and mechanical tests revealed that the polymer employed shows properties suitable for the production of tools to be used in aquaculture applications. Moreover, the samples were subjected to a biodegradation test in conditions that simulate the marine environment. The as-treated samples were characterized from gravimetrical,…
Materials for Respiratory Masks in the Context of COVID 19 Pandemic
2021
In the context of the COVID-19 pandemic and the lack of protective equipment worldwide, we aimed to study the literature for finding guidelines in the 3D manufacture of respiratory masks. We have searched for papers in CI-EXPANDED, SSCI, A&HCI, CPCI-S, CPCI-SSH, BKCI-S, BKCI-SSH, ESCI, CCR-EXPANDED, IC, using 3D printing materials sterilization and 3D printing materials disinfection keywords. From 80 results in databases, after refining, we selected six papers. We have also searched for manufacturers information regarding 3D printing materials sterilization or disinfection. We have found seven materials that are suitable for 3D printing and sterilization, with regards to multiple utili…
Disposal Behavior of Used Masks during the COVID-19 Pandemic in the Moroccan Community: Potential Environmental Impact.
2021
The spread of coronavirus disease-2019 (COVID-19) levied on the Moroccan authorities to increase their mask production capacity, which reached up to 12 million facemask units produced per day. This increase in personal protective equipment (PPE) production and consumption is an efficient tool to address the spread of COVID-19. However, this results in more plastic and microplastic debris being added into the land and marine environments, which will harm the ecosystem, wildlife, and public health. Such a situation needs deep individual behavior observation and tracking, as well as an assessment of the potential environmental impact of this new type of waste. For this reason, we assessed the …
Influence of compression sportswear on recovery and performance: A systematic review
2018
Compression garments are becoming increasingly popular among sportspeople who wish to improve performance and reduce their exercise discomfort and risk of injury. However, evidence for such effects is scarce. This paper presents the evidence following a review of the literature evaluating the effects of the application of compression garments on sports performance and recovery after exercise. The literature reviewed was the result of a search on the Web of Science, PubMed, and SPORTDiscus electronic databases for studies which analysed the effect of compression garments on physiological, psychological, and biomechanical parameters during and after exercise. These search criteria were met b…