Surfactant free fractions of metallic and semiconducting single-walled carbon nanotubes via optimised gel chromatography

We report the procedure of sorting/purification of carbon nanotubes by electronic type using chromatographic column with sodium dodecylsulfate (SDS) and sodium deoxycholate (DOC) solutions as the eluents. The non-commercial agarose gel in different concentrations has been tested in the process. It was found that in optimal gel concentration the fractionation resulted in ～96.2% yield of semiconducting species. Importantly, to get surfactant-free fractions the post-separation purification procedure has been carried out. The UV–vis–NIR and Raman spectroscopy have been utilised for the samples analysis. High resolution transmission microscopy and thermogravimetric analysis allowed to study the sample morphology and purity, respectively.     

Polyurethane/Polylactide-Based Electrospun Nonwovens as Carriers for Human Adipose-Derived Stromal Stem Cells and Chondrogenic Progenitor Cells

Articular cartilage dysfunctions are major cause of pain and disability and lead to serious health complications. Cell-based therapies are proposed as treatment methods for cartilage regeneration. In this study, we proposed polyurethane/poly(L-lactide-co-D, L-lactide)-based electrospun nonwovens as carriers for the delivery of human adipose-derived stromal stem cells. We found that 6:4 and 8:2 polyurethane/poly(L-lactide-co-D, L-lactide) initially enhance proliferative rate of human adipose-derived stromal stem cells, shorten their population doubling time, promote creation of functional chondrogenic nodules during chondrogenic differentiation, improve the collagen-2-to-collagen-1 protein ratio, and upregulate the expression of collagen-2 and aggrecan genes.     

Mechanism of MxOy nanoparticles/CNTs for catalytic carbonization of polyethylene and application to flame retardancy

Three kinds of metal oxide nanoparticles (Fe₃O₄, Co₃O₄, and Ni₂O₃) are produced on carbon nanotubes (CNTs). The synergistic effects rendered by the CNTs and metal oxide nanoparticles on carbonization of polyethylene (PE) are studied and applications to flame retardancy of PE are investigated systematically. The CNT‐Ni₂O₃ delivers the best performance and the mechanism pertaining to the enhanced flame retardancy is proposed and discussed. It is found that under the same conditions, the carbonization rate can be a factor to influence the flame retardancy performance. Among Fe, Co, and Ni, Ni has the fastest carbonation rate, which leads to the best flame retardancy performance. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45233.     

Unsaturated ester resins

Vinyl ester resins (VERs) are often described as a cross between unsaturated polyester resins and epoxy resins. VERs offer an upgrade to epoxy resins, and they tend to be selected when chemical and temperature resistance is required. This research was aimed at developing the synthesis of unsaturated ester resins (UERs), which are similar to VERs. UERs were synthesized by the addition of dihydrodicyclopentadienyl hydrogen maleate to the terminal epoxy groups in low‐molecular‐weight bisphenol A/epichlorohydrin epoxy resins. The effect of urethanization of UERs on the properties of the crosslinked polymer was also investigated. As crosslinking monomers, styrene and glycol dimethacrylates were used. The following properties of cured UERs were determined: the heat deflection temperature, alkali resistance, and the mechanical strength. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2627–2631, 2006     

Quantification of Se-Methylselenocysteine and Its γ-Glutamyl Derivative from Naturally Se-Enriched Green Bean (Phaseolus vulgaris vulgaris) After HPLC-ESI-TOF-MS and Orbitrap MS n -Based Identification

Orthogonal liquid chromatographic (ion exchange, reversed phase, and ion pairing) and mass spectrometric [electrospray ionization (ESI)-TOF-MS, ESI-Orbitrap MS, and inductively coupled plasma mass spectrometry (ICP-MS)] methods were addressed to identify and quantify selenium species from a naturally Se-enriched green bean (Phaseolus vulgaris vulgaris) sample after proteolytic digestion. While selenomethionine (10.1 mg/kg as Se) and selenate (9.5 mg/kg as Se) could be quantified in a straightforward way by anion exchange LC-ICP-MS technique, a multistep purification protocol was required to identify Se-methylselenocysteine and γ-glutamyl-Se-methylselenocysteine in an unambiguous way prior to quantification by using either in-source fragmentation (LC-ESI-TOF-MS) or collision-induced dissociation (LC-ESI-Orbitrap MS). Finally, Se-methylselenocysteine (2.6 mg/kg as Se) and γ-glutamyl-Se-methylselenocysteine (1.2 mg/kg as Se) could contribute to the overall selenium recovery of 72 %. This sample is the first of the Faboideae subfamily and Phaseolus ssp. to be speciated to such an extent for selenium including γ-glutamyl-Se-methylselenocysteine, a highly potential selenium species, which makes this bean material an ideal candidate for functional food purposes.     

An approach to modeling the rheological properties of food materials

The aim of this study was to develop a mathematical model describing the rheological properties of food materials, including the elastic modulus, consistency index, flow index and flow limit, that are not dependent on the tests (creep and compression stress relaxation) used to establish those values. A rheological model was designed as a parallel combination of spring, viscous and plastic elements. The model was verified logically and empirically based on the results of creep tests and compression stress relaxation tests performed on 10 × 10 × 10 mm cubes cut out from roasted turkey breast muscles. An analysis of the model’s susceptibility to variations in rheological properties indicates that the model is sensitive to changes in the values of the elastic modulus, flow limit and flow index, but it is less susceptible to changes in the consistency index. The model generates similar values of the rheological properties of the studied materials regardless of whether they had been determined based on the results of the creep test or the compression stress relaxation test.