Comparison of hydrogenated and unhydrogenated carbon films obtained by FCVA onto Ti6Al4V: Structure, hardness and biocompatibility study

This work compares hydrogenated and unhydrogenated carbon films as surfaces for implants. Thin films are deposited by a filtered cathodic vacuum arc (FCVA) process in a variable methane pressure in order to obtain very close sets of deposition conditions for the hydrogenated and unhydrogenated films. Ti6Al4V alloy is used as substrate. The structure is investigated by XRR, ERDA-RBS and Raman spectroscopy. The mechanical and physico-chemical properties such as adherence load, hardness and wettability are studied for the two sets of coatings on the metallic substrate. The biological approach is a study of the cytocompatibility of these films with MC3T3-E1 osteoblast-like cells and in particular the adhesion kinetics. The carbon coatings influence neither the morphology nor the early adhesion behaviour of these target cells on the substrates. This is probably due to similar hydrophilic surface energies of the tested control and carbon-coated test samples

Improvement of biological response of YAG laser irradiated polyethylene.

International audiencePE was manufd. by thermocompression of PE micro beads. This end product was then irradiated by a 1064 nm YAG laser. In the first part the phys. characteristics of untreated and laser irradiated samples are compared. DSC revealed a max. of crystallinity of PE, and YAG laser treatment did not influence the crystallinity. Weattability between PE and the laser irradiated PE (Li-PE) was similar with about 37 mJ cm-2. Differences appeared, however, as to the surface profile and the surface compn.: increase of the roughness of 0.20 mm for PE vs. 0.29 mm for Li-PE; XPS reveals that traces of stripping agents on PE mostly disappeared after surface cleaning by YAG laser treatment. Biol. tests confirmed the non-toxicity of polyethylene powder and revealed a 4-fold proliferation increase and a 2-fold vitality stimulation of L132 cells cultured on Li-PE with respect to those grown on untreated PE. No differences were obsd. as to the morphol. and cell adhesion between the two samples. The modified surface morphol. and surface compn. may explain the improved biol. reactions

Phase evolution, microstructure, and improved magnetic properties for off-stoichiometric SmFe12-based alloys

Low rare earth content and high intrinsic magnetic properties make SmFe12-based permanent magnets a potential candidate for NdFeB-based magnets in medium to high temperature environments. However, the easy formation of multiple ferromagnetic intergranular phases limits the preparation of high coercivity magnets. Composition optimization is an indispensable measure for the realization of high-performance magnets. In this work, off-stoichiometric composition design is employed to prepare SmFe12-based alloys. Ti is first introduced to inhibit the precipitation of α-Fe phase, obtaining a high coercivity of 484 kA/m, while the ribbon undergoes a reduction of remanence significantly. After regulating Fe–Co content to 11.5, the remanence recoveries from 0.51 to 0.65 T with a slight increase in coercivity (484–493 kA/m). Finally, Fe content is optimized to further improve magnetic properties, with both coercivity and remanence are improved simultaneously, reaching 509 kA/m and 0.70 T, respectively. Phase evolution, microstructure and their relationship with magnetic properties are investigated in detail. Micromagnetic simulation shows that the increased domain wall pinning effect induced by the refinement of grain size is the main reason for high coercivity. This work provides a feasible compositional design method for the preparation of high performance SmFe12-based alloys

A defined xeno-free and feeder-free culture system for the derivation, expansion and direct differentiation of transgene-free patient-specific induced pluripotent stem cells

10.1016/j.biomaterials.2013.12.050Biomaterials3592816-2826BIMA

Inter-laboratory comparisons of hexenuronic acid measurements in kraft eucalyptus pulps using a UV-Vis spectroscopic method

An inter-laboratory comparison of a UV-Vis spectroscopic method (TAPPI T 282 om-13 “Hexeneuronic acid content of chemical pulp”) for hexeneuronic acid measurements was conducted using three eucalyptus kraft pulps. The pulp samples were produced in a laboratory at kappa numbers of approximately 14, 20, and 35. The hexeneuronic acid contents of the three pulps were approximately 55–65 μmol/g, or with a variation of approximately 15%. Five laboratories from four different countries participated in this round-robin study as part of the evaluation of the TAPPI provisional method for upgrading to a TAPPI standard method. The comparative study showed that the orders of hexeneuronic acid content from low to high among the three pulp samples produced by four laboratories were in agreement. Replicate measurements were not conducted at the laboratory that produced an inconsistent order of hexeneuronic acid among the three pulp samples compared with the other four laboratories. The differences in hexeneuronic acid contents from different laboratories were systematic and consistent; that is, some laboratories consistently produced high values of hexeneuronic acid for all three samples. The comparative data of three pulp samples concluded that the measurement repeatability (within a laboratory) was less than 3% and reproducibility (among laboratories) was less than 16%. Application: Analytical test laboratories, pulp mills, and research organizations can use the information in this paper for chemical pulp analysi

Immobilized hepatocyte spheroids on galactose ligand-conjugated nanofiber scaffold

Transactions - 7th World Biomaterials Congress1753