Surface topography has a profound effect on the development of the nervous system, such as neuronal differentiation and morphogenesis. While the interaction of neurons and the surface topography of their local environment is well characterized, the neuron–topography interaction during the regeneration process remains largely unknown. To address this question, an anisotropic surface topography resembling linear grooves made from poly(ethylene‐vinyl acetate) (EVA), a soft and biocompatible polymer, using nanoimprinting, is established. It is found that neurons from both the central and peripheral nervous system can survive and grow on this grooved surface. Additionally, it is observed that axons but not dendrites specifically align with these grooves. Furthermore, it is demonstrated that neurons on the grooved surface are capable of regeneration after an on‐site injury. More importantly, these injured neurons have an accelerated and enhanced regeneration. Together, the data demonstrate that this anisotropic topography guides axon growth and improves axon regeneration. This opens up the possibility to study the effect of surface topography on regenerating axons and has the potential to be developed into a medical device for treating peripheral nerve injuries.
Low‐temperature (600°C) activation and recrystallization of the low‐pressure chemical vapor deposition (LPCVD) amorphous‐Si films B+‐ and
BF2+‐normalImplanted
with different implantation dosages and projection ranges have been investigated. The boron dopant in the amorphous‐Si layer can enhance the recrystallization, resulting in the shorter incubation time and smaller grain size then the undoped specimens. For the
BF2+‐normalImplanted
specimens, the existence of fluorine atoms could postpone the grain nucleation, leading to the longer incubation time and slower nucleation rate for the heavily doped specimens than the undoped ones. For the
BF2+‐normalImplanted
specimens, as the implantation peak reaches to the
α‐normalSi/SiO2
interface, the recoiled oxygen atoms from the oxide substrate would retard the grain nucleation and exhibit a significantly large grain size after a long time annealing. However, the recoiled oxygen atoms and the microdefects in the poly‐Si layers would offset the improvement in hole mobility. Higher hole mobilities and lower trap state densities were also observed for the
BF2+‐normalImplanted
specimens with respect to the B+‐implanted ones. It is attributed to the passivation effect of fluorine atoms within the poly‐Si layers.
The specimen preparation technique using focused ion beam (FIB) to generate cross-sectional transmission electron microscopy (XTEM) samples of chemical vapor deposition (CVD) of Tungsten-plug (W-plug) and Tungsten Silicides (WSix) was studied. Using the combination method including two axes tilting[l], gas enhanced focused ion beam milling[2] and sacrificial metal coating on both sides of electron transmission membrane[3], it was possible to prepare a sample with minimal thickness (less than 1000 A) to get high spatial resolution in TEM observation. Based on this novel thinning technique, some applications such as XTEM observation of W-plug with different aspect ratio (I - 6), and the grain structure of CVD W-plug and CVD WSix were done. Also the problems and artifacts of XTEM sample preparation of high Z-factor material such as CVD W-plug and CVD WSix were given and the ways to avoid or minimize them were suggested.
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