Evaluation of contour of unruptured cerebral aneurysm using three-dimensional CT cisternogram.

Angiography is gold standard technique as preoperative examination for unruptured aneurysmal surgery. Neurosurgeons have observed the unexpected irregular shape and size of the aneurysmal dome and neck in many cases of unruptured cerebral aneurysms during aneurysmal microsurgery, and known the discrepancy between the findings of angiography and operative view. We could not find out the report described the preoperative evaluation of outer-wall (contour) of aneurysm. In the present study, we attempted to evaluate the outer-wall of an unruptured cerebral aneurysm using three-dimensional CT cisternogram (3D-CTC) to provide useful preoperative information. The study was performed on three cases of unruptured cerebral aneurysm that were identified incidentally by MR angiography. We performed three-dimensional CT aniography (3D-CTA) and 3D-CTC for each patient. In the present study, we visualized the contours of vessels and aneurysms using a 3D-CTC in three cases of unruptured cerebral aneurysm. We found the discrepancy between the 3D-CTC contour image and the intra-luminal image 3D-CTA image. This method may be useful for the decision of the surgical approach and have the potential to evaluate the anatomical structure of aneurysmal dome and neck preoperatively.</p

Surface transfer doping of hydrogen-terminated diamond probed by shallow nitrogen-vacancy centers

The surface conductivity of hydrogen-terminated diamond is a topic of great interest from both scientific and technological perspectives. This is primarily due to the fact that the conductivity is exceptionally high without the need for substitutional doping, thus enabling a wide range of electronic applications. Although the conductivity is commonly explained by the surface transfer doping due to air-borne surface acceptors, there remains uncertainty regarding the main determining factors that govern the degree of band bending and hole density, which are crucial for the design of electronic devices. Here, we elucidate the dominant factor influencing band bending by creating shallow nitrogen-vacancy (NV) centers beneath the hydrogen-terminated diamond surface through nitrogen ion implantation at varying fluences. We measured the photoluminescence and optically detected magnetic resonance of the NV centers as well as the surface conductivity as a function of the implantation fluence. Our findings indicate that band bending is not exclusively determined by the work-function difference between diamond and the surface acceptor material, but by the finite density of surface acceptors. Furthermore, this study also suggests the presence of spatial inhomogeneities in the surface conductivity and the charge state of the NV centers when the implantation fluence is close to the density of negatively charged surface acceptors. This work emphasizes the importance of distinguishing work-function-difference-limited band bending and surface-acceptor-density-limited band bending when modeling the surface transfer doping and provides useful insights for the development of devices based on hydrogen-terminated diamond

Protein Transduction Method for Cerebrovascular Disorders

Many studies have shown that a motif of 11 consecutive arginines (11R) is one of the most effective protein transduction domains (PTD) for introducing proteins into the cell membrane. By conjugating this &#34;11R&#34;, all sorts of proteins can effectively and harmlessly be transferred into any kind of cell. We therefore examined the transduction efficiency of 11R in cerebral arteries and obtained results showing that 11R fused enhanced green fluorescent protein (11R-EGFP) immediately and effectively penetrated all layers of the rat basilar artery (BA), especially the tunica media. This method provides a revolutionary approach to cerebral arteries and ours is the first study to demonstrate the successful transductionof a PTD fused protein into the cerebral arteries. In this review, we present an outline of our studies and other key studies related to cerebral vasospasm and 11R, problems to be overcome, and predictions regarding future use of the 11R protein transduction method for cerebral vasospasm (CV).</p