Boosting thermal conductivity by surface plasmon polaritons propagating along a thin Ti film

We experimentally demonstrate a boosted in-plane thermal conduction by surface plasmon polaritons (SPPs) propagating along a thin Ti film on a glass substrate. Owing to a lossy nature of metal, SPPs can propagate over centimeter-scale distance even with a supported metal film, and resulting ballistic heat conduction can be quantitatively validated. Further, for a 100-nm-thick Ti film on glass substrate, a significant enhancement of in-plane thermal conductivity compared to bulk value ($\sim 35\%$) is experimentally shown. This study will provide a new avenue to employ SPPs for heat dissipation along a supported thin film, which can be readily applied to mitigate hot-spot issues in microelectronics.Comment: 3 figure

Synthesis of Cell-Adhesive Anisotropic Multifunctional Particles by Stop Flow Lithography and Streptavidin–Biotin Interactions

Cell-adhesive particles are of significant interest in biotechnology, the bioengineering of complex tissues, and biomedical research. Their applications range from platforms to increase the efficiency of anchorage-dependent cell culture to building blocks to loading cells in heterogeneous structures to clonal-population growth monitoring to cell sorting. Although useful, currently available cell-adhesive particles can accommodate only homogeneous cell culture. Here, we report the design of anisotropic hydrogel microparticles with tunable cell-adhesive regions as first step toward micropatterned cell cultures on particles. We employed stop flow lithography (SFL), the coupling reaction between amine and N-hydroxysuccinimide (NHS) and streptavidin–biotin chemistry to adjust the localization of conjugated collagen and poly-l-lysine on the surface of microscale particles. Using the new particles, we demonstrate the attachment and formation of tight junctions between brain endothelial cells. We also demonstrate the geometric patterning of breast cancer cells on particles with heterogeneous collagen coatings. This new approach avoids the exposure of cells to potentially toxic photoinitiators and ultraviolet light and decouples in time the microparticle synthesis and the cell culture steps to take advantage of the most recent advances in cell patterning available for traditional culture substrates.National Institutes of Health (U.S.) (GM092804)National Science Foundation (U.S.) (CMMI-1120724 and DMR-1006147)Samsung Scholarship Foundatio

다변량 기법을 이용한 혼합치열기 분석법

Objective: To develop a mixed dentition analysis method in consideration of the normal variation of tooth sizes. Methods: According to the tooth-size of the maxillary central incisor, maxillary 1st molar, mandibular central incisor, mandibular lateral incisor, and mandibular 1st molar, 307 normal occlusion subjects were clustered into the smaller and larger tooth-size groups. Multiple regression analyses were then performed to predict the sizes of the canine and premolars; for the 2 groups and both genders separately. For a cross validation dataset, 504 malocclusion patients were assigned into the 2 groups. Then multiple regression equations were applied. Results: Our results show that the maximum errors of the predicted space for the canine, 1st and 2nd premolars were 0.71 and 0.82 mm residual standard deviation for the normal occlusion and malocclusion groups, respectively. For malocclusion patients, the prediction errors did not imply a statistically significant difference depending on the types of malocclusion nor the types of tooth-size groups. The frequency of prediction error more than 1 mm and 2 mm were 17.3% and 1.8%, respectively. The overall prediction accuracy was dramatically improved in this study compared to that of previous studies. Conclusions: The computer aided calculation method used in this study appeared to be more efficient. (Korean J Orthod 2009;39(2):112-119)본 연구는 서울대학교 치과병원 연구비(04-2007-0013) 지원을 받아 시행되었음.

Elevated RalA activity in the hippocampus of PI3K gamma knock-out mice lacking NMDAR-dependent long-term depression

Phosphoinositide 3-kinases (PI3Ks) play key roles in synaptic plasticity and cognitive functions in the brain. We recently found that genetic deletion of PI3K gamma, the only known member of class IB PI3Ks, results in impaired N-methyl-D-aspartate receptor-dependent long-term depression (NMDAR-LTD) in the hippocampus. The activity of RalA, a small GTP-binding protein, increases following NMDAR-LTD inducing stimuli, and this increase in RalA activity is essential for inducing NMDAR-LTD. We found that RalA activity increased significantly in PI3K gamma knockout mice. Furthermore, NMDAR-LTD-inducing stimuli did not increase RalA activity in PI3K gamma knockout mice. These results suggest that constitutively increased RalA activity occludes further increases in RalA activity during induction of LTD, causing impaired NMDAR-LTD. We propose that PI3K gamma regulates the activity of RalA, which is one of the molecular mechanisms inducing NMDAR-dependent LTD.open1

Unilateral Epileptic Negative Myoclonus Following Focal Lesion of the Postcentral Cerebral Cortex Due to Acute Middle Cerebral Infarction

Here we report a patient who suffered an acute infarction of the contralateral postcentral cerebral cortex and subsequently developed unilateral partial epilepsy with negative myoclonus. The findings of brain magnetic resonance imaging, polygraphic recordings of the postcentral somatosensory area, and response to anticonvulsant treatment support the presence of a cause-and-effect relationship, thereby providing evidence for a pathophysiological substrate for epileptic negative myoclonus