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The mammalian central nervous system (CNS) has little capacity for self-repair after injury, and neurons are not capable of proliferating. Therefore, neural tissue engineering that combines neural stem and progenitor cells and biologically derived polymer scaffolds may revolutionize the medical approach to the treatment of damaged CNS tissues. Neural stem and progenitor cells isolated from embryonic rat cortical or subcortical neuroepithelium were dispersed within type I collagen, and the cell–collagen constructs were cultured in serum-free medium containing basic fibroblast growth factor. The collagen-entrapped stem and progenitors actively expanded and efficiently generated neurons, which developed neuronal polarity, neurotransmitters, ion channels/receptors, and excitability. Ca2+ imaging showed that differentiation from BrdU+/TuJ1− to BrdU−/TuJ1+ cells was accompanied by a shift in expression of functional receptors for neurotransmitters from cholinergic and purinergic to predominantly GABAergic and glutamatergic. Spontaneous postsynaptic currents were recorded by patch-clamping from precursor cell-derived neurons and these currents were partially blocked by 10-μM bicuculline, and completely blocked by additional 10 μM of the kainate receptor antagonist CNQX, indicating an appearance of both GABAergic and glutamatergic synaptic activities. Staining with endocytotic marker FM1-43 demonstrated active synaptic vesicle recycling occurring among collagen-entrapped neurons. These results show that neural stem and progenitor cells cultured in 3D collagen gels recapitulate CNS stem cell development; this is the first demonstration of CNS stem and progenitor cell-derived functional synapse and neuronal network formation in a 3D matrix. The proliferative capacity and neuronal differentiating potential of neural progenitors in 3D collagen gels suggest their potential use in attempts to promote neuronal regeneration in vivo.

In this paper, a thermodynamic constitutive model previously proposed by the authors was further developed in order to be applicable for the simulation of thermomechanical behavior of shape memory alloys under different loading conditions. The volume fractions of austenite and martensite variants were used as internal variables to describe the microstructural evolution. The model was used to investigate the behavior of a round tube Cu–Al–Zn–Mn polycrystalline shape memory alloy under various mechanical loads, including non-proportional loading, torsion cycling in opposite directions and the shape memory effect. The non-proportional loading simulation results were compared with experimental results reported in the literature.

Rapamycin (Sirolimus) is a potent immunosuppressive drug that reduces renal transplant rejection. Hyperlipidemia is a significant side effect of rapamycin treatment, and frequently leads to cardiovascular disease. Adipocyte fatty acid binding protein (aP2) is a member of the cytoplasmic fatty acid binding protein (FABP) family. aP2 has been shown to affect insulin sensitivity, lipid metabolism, lipolysis, and has recently been shown to play an important role in atherosclerosis. We found that aP2 messenger RNA (mRNA) was increased in human THP-1 cells after rapamycin treatment. Exposure of human differentiated THP-1 cells to rapamycin led to a time- and dose-dependent induction of aP2 mRNA expression. While aP2 expression was undetectable in undifferentiated THP-1 cells, aP2 was induced in these cells by rapamycin. These data suggest that rapamycin-induced aP2 may play a role in increased triglyceride accumulation.