Neutral sphingomyelinase and breast cancer research.

Our understanding of the functions of neutral sphingomyelinase (N-SMase) signaling has advanced over the past decade. In this review, we focus on the roles and regulation of N-SMase 1, N-SMase 2, N-SMase 3, an enzyme that generates the bioactive lipid ceramide through the hydrolysis of the membrane lipid sphingomyelin. A large body of work has now implicated N-SMase 2 in a diverse set of cellular functions, physiological processes, and disease pathologies. We focus on different aspects of this enzyme's regulation from transcriptional, post-translational, and biochemical. Furthermore, we expected N-SMase involvement in cellular processes including inflammatory signaling, cell growth, apoptosis, and tumor necrosis factor which in turn play important roles in pathologies such as cancer metastasis, variable disease, and other organ system disorders. Lastly, we examine avenues where targeted N-SMase inhibition may be clinically beneficial in disease scenarios.

Graphene oxide nanosheet wrapped white-emissive conjugated polymer nanoparticles.

We have demonstrated the preparation of white-emissive conjugated polymer nanoparticles wrapped with graphene oxide (GO) nanosheets. Highly stable, GO-wrapped, poly(9,9-di-n-octylfluorenyl-2,7-diyl) nanoparticles (GO-PFO NPs) with diameters in the range 30-150 nm were successfully obtained by utilizing the GO nanosheets as an interface stabilizer in an emulsification process. The synthesized GO-PFO NPs exhibited unique white-emitting photoluminescence with a characteristic green-emissive broad band above 500 nm, which was distinct from the photoluminescent behavior of PFO NPs without GO. This green emission was deduced to originate from the presence of the GO nanosheet shell surrounding the PFO NPs, rather than from luminescence of GO itself or formation of keto defects in the PFO chain. PL decay analysis showed that the GO-wrapped PFO NPs had a longer luminescence lifetime in comparison to PFO NPs without GO, and highly efficient energy transfer to lower energy state induced by the GO occurred.

A near single crystalline TiO2 nanohelix array: enhanced gas sensing performance and its application as a monolithically integrated electronic nose.

We present high performance gas sensors based on an array of near single crystalline TiO(2) nanohelices fabricated by rotating oblique angle deposition (OAD). The combination of large surface-to-volume ratio, extremely small size (<30 nm) comparable to the Debye length, a near single crystallinity of TiO(2) nanohelices, together with the unique top-and-bottom electrode configuration hugely improves the H(2)-sensing performance, including ∼10 times higher response at 50 ppm, approximately a factor of 5 lower detection limit, and much faster response time than the conventional TiO(2) thin film devices. Beyond such remarkable performance enhancement, the excellent compatibility of the OAD method compared with the conventional micro-fabrication technology opens a new avenue for monolithic integration of high-performance chemoresistive sensors to fabricate a simple, low cost, reliable, yet fully functional electronic nose and multi-functional smart chips for in situ environmental monitoring.

Effective projection theory in a correlated electron system.

We propose an efficient method for nonperturbative calculation of Green's function in a correlated electron system. The key idea of the method is to project out irrelevant operators having zero norm in the ground state, which we refer to as effective projection theory. We apply the method to a mesoscopic Anderson model and show that for a given wavefunction ansatz, equations of motion can be closed only by relevant operators, allowing easy calculation of the zero-temperature Green's function. It turns out that the resulting Green's functions reproduce exact limits of both weak and strong interactions. The accuracy is also verified for small systems by comparison with exact diagonalization results, revealing that effective projection theory captures the essential correlated features in the entire regime of interactions.