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Application of polymer

Kostas Komnitsas, Evangelos Petrakis, Georgios Bartzas, Vassiliki Karmali
Socio-economic data on nickel and cobalt show their importance throughout the entire metal value chain, from mining to end use, disposal and recycling. Thus, the extraction of both metals from primary and secondary raw materials as well as from wastes is currently considered strategically important for the industry and the society. In this paper heap leaching of Greek low-grade saprolitic laterites, with Ni content 0.97%, was investigated. The main parameters studied involved the strength of the H2 SO4 solution used (49 and 147 g L-1 ) and the effect of adding sodium sulfite (Na2 SO3 ) in the leaching medium...
January 30, 2019: Science of the Total Environment
Ehsan Saburi, Maryam Islami, Simzar Hosseinzadeh, Abbas Shapouri Moghadam, Reyhaneh Nassiri Mansour, Esmaeel Azadian, Zeinab Joneidi, Amin Reza Nikpoor, Mohammad Hassan Ghadiani, Zohreh Khodaii, Abdolreza Ardeshirylajimi
Due to the several limitations that surgeons are faced during bone tissue implantation there are daily increases in introducing new cell-co-polymer composites for use in bone tissue engineering approaches. In this study tried to develop a suitable nanostructured bio-composite for enhancing osteogenic differentiation of the human induced pluripotent stem cells (iPSCs). Polyvinylidene fluoride-Graphene oxide (PVDF-GO) nanofibers was fabricated by electrospinning and then characterized using scanning electron microscope, tensile and viability assays...
February 14, 2019: Gene
José Grau, Juan L Benedé, Javier Serrano, Andrea Segura, Alberto Chisvert
This work describes a new analytical method useful for monitoring the human exposure to the endocrine-disrupting plasticizer triphenyl phosphate (TPP) via nail polish use. The method allows trace determination of this parent compound and its main metabolite, namely diphenyl phosphate (DPP), in urine samples of nail polish users. The method is based on a novel microextraction technique termed stir bar sorptive-dispersive microextraction (SBSDME) using a magnetic composite made of CoFe2 O4 magnetic nanoparticles embedded into a mixed-mode weak anion exchange polymer (Strata™ -X-AW), followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS)...
February 7, 2019: Journal of Chromatography. A
Xiujuan Wang, Hao Ding, Xinru Yu, Xizhi Shi, Aili Sun, Dexiang Li, Jian Zhao
Molecularly imprinted silica layers coated to quantum dots (MIP-QDs) were successfully fabricated and applied as the fluorescence probe for highly selective and sensitive determination of diethylstilbestrol (DES). Scanning electron microscopy, Transmission electron microscopy, and Fourier transform infrared spectroscopy indicated successful grafting of molecularly imprinted silica layers onto the surface of QDs. Furthermore, the fluorescence assay based on the MIP-QDs showed excellent selectivity and fluorescence quenching capability in optimal conditions and a good linear relationship was obtained in the range of 2...
May 15, 2019: Talanta
Lanqing Li, Huijun Zheng, Lili Guo, Lingbo Qu, Lanlan Yu
A special electrochemical sensor was developed based on molecularly imprinted polymer (MIP), which was formed by the dopamine (DA) self-polymerization on the surface of Pd-Cu bimetallic alloy functionalized poly (diallyldimethylammonium chloride) -dispersed graphene (PDDA-Gr). This sensor takes advantages of molecularly imprinted technique and nanocomposite to realize the application of amaranth determination with high selectivity and sensitivity. In this study, the nanocomposite PDDA-Gr-(Pd-Cu) characterized by various techniques provides large surface area and accelerates the electron transfer process...
May 15, 2019: Talanta
David G Leach, Simon Young, Jeffrey D Hartgerink
Macroscale biomaterials, such as preformed implantable scaffolds and injectable soft materials, possess powerful synergies with anti-cancer immunotherapies. Immunotherapies on their own typically have poor delivery properties, and often require repeated high-dose injections that result in serious off-tumor effects and/or limited efficacy. Rationally designed biomaterials allow for discrete localization and controlled release of immunotherapeutic agents, and have been shown in a large number of applications to improve outcomes in the treatment of cancers via immunotherapy...
February 13, 2019: Acta Biomaterialia
Thorsteinn Loftsson, Phennapha Saokham, André Rodrigues Sá Couto
Cyclodextrins (CDs) are oligosaccharides that self-assemble in aqueous solutions to form transient clusters, nanoparticles and small microparticles. The critical aggregation concentration (cac) of the natural αCD, βCD and γCD in pure aqueous solutions was estimated to be 25, 8 and 9 mg/ml, respectively. The cac of 2-hydroxypropyl-β-cyclodextrin (HPβCD), that consists of mixture of isomers, was estimated to be significantly higher or 118 mg/ml. Addition of chaotropic agents (i.e. that disrupts non-covalent bonds such as hydrogen bonds) to the aqueous media increases the cac...
February 13, 2019: International Journal of Pharmaceutics
Renato Graciano de Paula, Amanda Cristina Campos Antoniêto, Liliane Fraga Costa Ribeiro, Neha Srivastava, Anthonia O'Donovan, P K Mishra, Vijai K Gupta, Roberto N Silva
Lignocellulose is a rich and sustainable globally available carbon source and is considered a prominent alternative raw material for producing biofuels and valuable chemical compounds. Enzymatic hydrolysis is one of the crucial steps of lignocellulose degradation. Cellulolytic and hemicellulolytic enzyme mixes produced by different microorganisms including filamentous fungi, yeasts and bacteria, are used to degrade the biomass to liberate monosaccharides and other compounds for fermentation or conversion to value-added products...
February 13, 2019: Biotechnology Advances
Chandran Murugan, Varsha Sharma, Rajesh Kumar Murugan, Gnanasekar Malaimegu, Anandhakumar Sundaramurthy
In recent years, novel two-dimensional (2D) nanomaterials are of great interest for diverse potential applications such as device fabrication, energy storage, sensing and theranostics because of their superlative physical features namely, large surface area, minimal thickness, tunable composition and easier surface modification methods. Rapid exploration in design and fabrication of 2D nano-structures have opened new avenue for cancer theranostics as it can encapsulate group of cancer cells and inflict major damage with great specificity in a non-invasive manner...
February 13, 2019: Journal of Controlled Release: Official Journal of the Controlled Release Society
Zheng Zhao, Chao Chen, Wenting Wu, Fenfen Wang, Lili Du, Xiaoyan Zhang, Yu Xiong, Xuewen He, Yuanjing Cai, Ryan T K Kwok, Jacky W Y Lam, Xike Gao, Pingchuan Sun, David Lee Phillips, Dan Ding, Ben Zhong Tang
The exciting applications of molecular motion are still limited and are in urgent pursuit, although some fascinating concepts such as molecular motors and molecular machines have been proposed for years. Utilizing molecular motion in a nanoplatform for practical application has been scarcely explored due to some unconquered challenges such as how to achieve effective molecular motion in the aggregate state within nanoparticles. Here, we introduce a class of near infrared-absorbing organic molecules with intramolecular motion-induced photothermy inside nanoparticles, which enables most absorbed light energy to dissipate as heat...
February 15, 2019: Nature Communications
Fernando Maya, Brett Paull
This review summarizes recent development made in the incorporation of functional materials into organic polymer monoliths, together with new monolithic forms and formats, which enhance their application as supports and stationary phase materials for sample preparation and chromatographic separations. While polymer monoliths are well known supports for the separation of large molecules, recent development have been made to improve their features for the separation of small molecules. The selectivity and performance of organic polymer monoliths has been improved by the incorporation of different materials, such as metal-organic frameworks, covalent organic frameworks, or other types of nanostructured materials (carbon nanohorns, nanodiamonds, polyoxometalates, layered double hydroxides, or attapulgite)...
February 15, 2019: Journal of Separation Science
Maayan Levin, Adar Sonn-Segev, Yael Roichman
We study the enhancement of the stiffness of two families of hydrogels (polyacrylamide, PAAm, and polydimethylacrylamide, PDMA) due to the additions of very small amounts of silica nanofillers. It is well established that high concentrations of silica nanoparticles enhance the toughness of both hydrogel types, but significantly more for the PDMA based gels that adsorb readily to silica surfaces. In order to decouple the structural changes in the gels that stem either from polymerization kinetics or from the interactions between nanofillers and polymers, we use a photoinitiator for the polymerization of the composite gels that promotes the structural homogeneity of the hydrogels...
February 14, 2019: Journal of Chemical Physics
Jiaxiang Li, Ran Zhang, Mingming Ding, Tongfei Shi
We investigate the diffusion dynamics of a single polymer strongly adsorbed on surfaces in an extremely broad chain length and surface roughness by means of molecular dynamics simulations. Our simulations demonstrate that with the increase in chain length, the diffusion dynamics of polymer chains exhibits three regimes: the Rouse dynamics with D ∼ N-1 when the lateral size of polymer chains is smaller than a half of distance between obstacles on rough surfaces; the reptationlike dynamics with D ∼ N-1.5 and τr ∼ N3 when the obstacles inhibit the freely Rouse behavior of polymer chains; and the quasi-Rouse dynamics with D ∼ N-1 and τr ∼ N2...
February 14, 2019: Journal of Chemical Physics
Souhir Sabri, Ahmad Najjar, Yehia Manawi, Nahla Omer Eltai, Asma Al-Thani, Muataz Ali Atieh, Viktor Kochkodan
Polysulfone (PS) membranes blended with different loadings of arabic gum (AG) were synthesized using phase inversion method and the antibacterial properties of the synthesized membranes were tested using a number Gram-negative ( Escherichia coli , Klebsiella pneumonia and Pseudomonas aeruginosa ) and Gram-positive ( Staphylococcus aureus ) bacterial species. It was shown that AG addition to the dope polymer solutions essentially changed porous structure, hydrophilicity and zeta potential of the cast PS/AG membranes...
February 14, 2019: Membranes
Bei Su, Ying-Guo Zhou
Poly(cyclohexylene dimethylene cyclohexanedicarboxylate) (PCCE) is a kind of copolyester polymer with excellent toughness and outstanding flexibility. However, the opacity caused by crystallization limits the widespread application of PCCE in products that have transparency requirements. The effects of 1,3:2,4-Di-p-methylbenzylidene sorbitol (MDBS) on the crystallization behavior, transparency, and mechanical properties of a PCCE melt were investigated via differential scanning calorimetry (DSC), spectrophotometry, and tensile testing...
February 14, 2019: Materials
Weiguang Wang, Boyang Huang, Jae Jong Byun, Paulo Bártolo
Biomanufacturing is a relatively new research domain focusing on the use of additive manufacturing technologies, biomaterials, cells and biomolecular signals to produce tissue constructs for tissue engineering. For bone regeneration, researchers are focusing on the use of polymeric and polymer/ceramic scaffolds seeded with osteoblasts or mesenchymal stem cells. However, the design of high-performance scaffolds in terms of mechanical, cell-stimulation and biological performance is still required. This is the first paper investigating the use of an extrusion additive manufacturing system to produce poly(ε-caprolactone) (PCL), PCL/graphene nanosheet (GNS) and PCL/carbon nanotube (CNT) scaffolds for bone applications...
January 31, 2019: Journal of the Mechanical Behavior of Biomedical Materials
Yan Yang, Nan Zheng, Yanjun Zhou, Weiguang Shan, Jie Shen
Fibrous films have attracted considerable attention in the field of drug delivery and wound dressings owing to their porous structure and highly aligned fiber orientation. However, current fabrication methods such as electrospinning have certain limitations, including high voltage requirement and conductivity dependency. This has greatly hindered the product development and applications of fibrous films. The objective of the present study was to develop a high throughput and solventless fiber fabrication method via centrifugal melt spinning (CMS) technology...
February 12, 2019: International Journal of Pharmaceutics
Sampa Maiti, Saikat Manna, Jingjing Shen, Aaron P Esser-Kahn, Wenjun Du
Polymeric nanoparticles (NPs) derived from self-assemblies of amphiphilic polymers have demonstrated great potentials in clinical applications. However, there are challenges ahead. Notably, immunotoxicity remains as a major roadblock that deters the NPs further applications. Studies suggested that the hydrophobic component is a primary cause, yet biocompatible hydrophobic carbohydrate-based polymers may help mitigate this issue. Herein we design and synthesize novel NP systems having glucose poly(orthoesters) hydrophobic scaffold and polyethylene glycol (PEG) hydrophilic shell...
February 15, 2019: Journal of the American Chemical Society
Afsana, Vineet Jain, Nafis Haider, Keerti Jain
BACKGROUND: Personalized medicines are becoming more popular as they enables the use of patient's genomics and hence help in better drug design with fewer side effects. In fact several doses can be combined into one dosage form which suits the patient's demography. 3 Dimensional (3D) printing technology for personalized medicine is a modern day treatment method based on genomics of patient. METHODS: 3D printing technology uses digitally controlled devices for formulating API and excipients in a layer by layer pattern for developing a suitable personalized drug delivery system as per the need of patient...
February 15, 2019: Current Pharmaceutical Design
Jubair Ahmed, Esra Altun, Mehmet O Aydogdu, Oguzhan Gunduz, Laxmi Kerai, Guogang Ren, Mohan Edirisinghe
Cinnamon-containing polycaprolactone (PCL) bandages were produced by pressurised gyration and their anti-fungal activities against Candida albicans were investigated. It was found that by preparing and spinning polymer solutions of cinnamon with PCL, fibres capable of inhibiting fungal growth could be produced, as observed in disk diffusion tests for anti-fungal susceptibility. Fascinatingly, compared with raw cinnamon powder, the novel cinnamon-loaded fibres had outstanding long-term activity. The results presented here are very promising and may indeed accelerate a new era of using completely natural materials in biomedical applications, especially in wound healing...
February 15, 2019: International Wound Journal
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