The application of an in situ karyotyping technique for mesenchymal stromal cells: a validation and comparison study with classical G-banding

The cytogenetic analysis of mesenchymal stromal cells (MSCs) is essential for verifying the safety and stability of MSCs. An in situ technique, which uses cells grown on coverslips for karyotyping and minimizes cell manipulation, is the standard protocol for the chromosome analysis of amniotic fluids. Therefore, we applied the in situ karyotyping technique in MSCs and compared the quality of metaphases and karyotyping results with classical G-banding and chromosomal abnormalities with fluorescence in situ hybridization (FISH). Human adipose- and umbilical cord-derived MSC cell lines (American Type Culture Collection PCS-500-011, PCS-500-010) were used for evaluation. The quality of metaphases was assessed by analyzing the chromosome numbers in each metaphase, the overlaps of chromosomes and the mean length of chromosome 1. FISH was performed in the interphase nuclei of MSCs for 6q, 7q and 17q abnormalities and for the enumeration of chromosomes via oligo-FISH in adipose-derived MSCs. The number of chromosomes in each metaphase was more variable in classical G-banding. The overlap of chromosomes and the mean length of chromosome 1 as observed via in situ karyotyping were comparable to those of classical G-banding (P=0.218 and 0.674, respectively). Classical G-banding and in situ karyotyping by two personnel showed normal karyotypes for both cell lines in five passages. No numerical or structural chromosomal abnormalities were found by the interphase-FISH. In situ karyotyping showed equivalent karyotype results, and the quality of the metaphases was not inferior to classical G-banding. Thus, in situ karyotyping with minimized cell manipulation and the use of less cells would be useful for karyotyping MSCs.     

Effects of Zn, Al and Ti substitution on the electrochemical properties of LiNiO2 synthesized by the combustion method

LiNi_{1 ? y} Ti _y O₂ (0.000 ≤ y ≤ 0.100) and LiNi_0.990M_0.010O2 (M = Zn, Al, and Ti) were synthesized by the combustion method. The effects of Zn, Al and Ti substitution for Ni of LiNiO₂ on the electrochemical properties of LiNiO₂ were investigated. LiNi_0.995Ti_0.005O₂ has the largest first discharge capacity (188.1 mA h/g) among the Ti-substituted samples. LiNi_0.990Ti_0.010O₂ has a relatively large first discharge capacity (185.5 mA h/g) and a relatively good cycling performance. Among LiNi_0.990M_0.010O₂ (M = Ni, Zn, Al, and Ti), LiNiO₂ has the largest discharge capacities at a rate of 0.1 C from n = 1(189.3 mA h/g) to n = 10. LiNi_0.990Al_0.010O₂ has the lowest discharge capacities from n = 1 to n = 10, but it has the best cycling performance. LiNi_0.990Zn_0.010O₂ showed poor crystallinity, LiNi_0.990Ti_0.010O₂ showed high cation mixing, and LiNi_0.990Al_0.010O₂ had good crystallinity and showed low cation mixing. Fewer occurrence of phase transitions and the least change of the ?dx/|dV| vs. voltage curve at the second cycle from the curve at the first cycle of LiNi_0.990Al_0.010O₂ suggest that Al substitution stabilizes the structure and leads to a good cycling performance.     

Preparation of 5-Alkenyl- and 5-Dienyl-2-pyrrolidinone Derivatives

Glutamic acid is readily converted into N-butenyl-2-pyrrolidi-none-5-carboxaldehyde. The novel butenyl protecting group allows the synthesis of this aldehyde which can be olefinated using standard Wittig methodology.     

Synthesis and properties of near IR induced self-healable polyurethane/graphene nanocomposites

A series of self-healable polyurethane (SHPU)/modified graphene (MG) nanocomposites were synthesized from poly(tetramethylene glycol) (PTMG) and 4,4′-methylene diphenyl diisocyanate (MDI) with minute amounts (0–1 wt%) of MG which was chemically modified graphene oxide (GO) with phenyl isocyanate and reduced in the presence of phenylhydrazine.     

pH-Dependent Release from Monoolein Cubic Phase Containing Hydrophobically Modified Chitosan

Monoolein (MO) cubic phase incorporating hydrophobically modified chosan (Hm chitosan) was prepared to obtain a pH-dependent release. Following calorimetric study, Hm chitosan had little effect on the crystal structure of MO cubic phase under acidic condition where Hm chitosan is readily soluble. At a higher pH (e.g., pH 9.0), however, the crystal structure of MO cubic phase was disturbed, possibly due to the insolubilization of Hm chitosan at the alkali condition. Whether the dye included in the cubic phase is anionic (amaranth) or cationic (methylene blue), the release from the cubic phase was suppressed as the pH of release medium increased. The structural change of cubic phase caused by the insolubilization of Hm chitosan, or the blockage of the water channel of the cubic phase by precipitated Hm chitosan would be responsible for the suppressed released.     

Investigation on ion movement in the fringe-field switching mode depending on resistivity of alignment layer and dielectric anisotropic sign of liquid crystal

Adsorption and desorption of ions at interface between liquid crystal and alignment layer in liquid crystal displays play a crucial role in residual direct current voltage associated with image sticking. In this article, the dependency of such adsorption and desorption of ions on resistivity of alignment layer and sign of liquid crystal dielectric anisotropy in the fringe-field liquid crystal cell has been investigated. Our studies show that the time constant of ions during adsorption and desorption depends upon resistivity and dielectric constant of liquid crystal and alignment layer, and most strongly influenced by the resistivity of alignment layer such that the one with lower resistivity in two orders shows much faster adsorption and desorption at the interface than that of the one with higher resistivity.     

Ferroelectric liquid crystals from banana-shaped achiral molecules with vinyl end groups

Banana-shaped achiral compounds, the 1,3-phenylene bis[4-(alkenyloxyphenyliminomethyl)benzoate]s, were synthesized with varying length of the alkenyl group; their ferroelectric properties are described. The smectic mesophases, including a switchable chiral smectic C (SmC*) phase, were characterized by differential scanning calorimetry, polarizing optical microscopy and the triangular wave method. The presence of vinyl groups at the ends of the linear side-wings in the banana-shaped achiral molecules, containing a Schiff's base mesogen, induced a decrease in melting temperature and formation of the switchable SmC* phase in the melt. The compound having the octenyloxy group exhibited a spontaneous polarization of 120 nC cm^?2 on reversal of an applied electric field.     

Etching Characteristics and Mechanisms of Mo and Al2O3 Thin Films in O2/Cl2/Ar Inductively Coupled Plasmas: Effect of Gas Mixing Ratios

An investigation of etching behaviors for Mo and Al₂O₃ thin films in O₂/Cl₂/Ar inductively coupled plasmas at constant gas pressure (6 mTorr), input power (700 W) and bias power (200 W) was carried out. It was found that an increase in Ar mixing ratio for Cl₂/Ar plasma results in non-monotonic etching rates with the maximums of 160 nm/min at 60 % Ar for Mo and 27 nm/min at 20 % Ar for Al₂O₃. The addition of O₂ in the Cl₂/Ar plasma causes the non-monotonic Mo etching rate (max. 320 nm/min at 40–45 % O₂) while the Al₂O₃ etching rate decreases monotonically. The model-based analysis of etching kinetics allows one to relate the non-monotonic etching rates in Cl₂/Ar plasma to the change in the etching regime from the ion-flux-limited mode (at low Ar mixing ratios) to the neutral-flux-limited mode (for high Ar mixing ratios). In the Cl₂/O₂/Ar plasma, the non-monotonic Mo etching rate is probably due to the change in reaction probability.