Exciton localization of single-walled carbon nanotubes revealed by femtosecond excitation correlation spectroscopy

Photoluminescence (PL) dynamics in single-walled carbon nanotubes (SWNTs) has been studied by the femtosecond excitation correlation method with a 150 fs time resolution. The SWNT samples were synthesized by different methods and suspended in gelatin films or D2O solutions. The PL dynamics of SWNTs depends on the local environment surrounding the SWNTs rather than the synthesis methods. The very weak temperature dependence of PL and the environment-dependent PL reveal that the PL relaxation process is dominated by the interplay between free excitons and weakly localized excitons

Image processing technique for detection of a particular object from motion images

This paper deals with the detection of the rescue target as a particular object from motion images under bad weather conditions. When shipwrecks occur, the searching activities for rescue is done using an airplane. The detection of the rescue target such as life rafts depends on a visual search by human eyes. To detect a small rescue target in a wide sea area, the searching man must monitor motion sights under nasty weather. The human eyes sometimes loses its sight and the ability of detection fails owing to the long flight and the nasty weather. To support the searching activities in the case of a marine casualty, we propose motion image processing techniques using the improved S/N ratio and dynamic range of the image data of the rescue target in the motion images under bad conditions </p

Detection of a particular object from environmental images under various conditions

In a current study of environmental information, it is important to detect the particular object from environmental images under various conditions for security such as navigation system of ships, bird-watching for the prevention of various damage, invaders check and human rescue in the marine casualty. This paper deals with the image processing techniques for the detection of the rescue target as a particular object from environmental images. When a marine casualty occurs the detection of the rescue target such as life rafts depends on the visual search of human eyes. It is predicted, however, that human eyes sometimes lose their sight and the ability of the detection falls owing to the long flight and a bad weather. For a practical purpose of the prompt rescue of human life, the development of the searching support system in place of human eyes is required. To realize a new type searching system for the detection of the rescue target, the development of new type image processing techniques in real time manner is important. At the first step of our study, we attempt to develop image processing techniques, in order to accurately detect the rescue target under various </p

Detection of a particular object from motion images under bad condition

This paper deals with the detection of the rescue target as a particular object from motion images under bad conditions. When shipwrecks occur, the search activities of rescue are done using an airplane. The detection of the rescue target such as a life raft depends on visual search of human eyes. To detect a small rescue target in the wide sea, the searcher man must monitor motion sights in nasty weather. In order to carry out the prompt rescue of human life, development of searching support system using image processing techniques in place of the human eye is required It is very difficult to process the motion images taken by the airplane, because these images are inferior due to shaking of the airplane, sunshine reflections and crest waves under bad conditions. We make a simulation experiment for detection of the rescue target from images. To get basic design data for development of the searching system in the case of a marine casualty, we propose motion image processing techniques using improved S/N ratio and dynamic range of the image data of the rescue target in the motion images under bad conditions </p

CD4-Independent Human Immunodeficiency Virus Infection Involves Participation of Endocytosis and Cathepsin B

During a comparison of the infectivity of mNDK, a CD4-independent human immunodeficiency virus type 1 (HIV-1) strain, to various cell lines, we found that HeLa cells were much less susceptible than 293T and TE671 cells. Hybridoma cells between HeLa and 293T cells were as susceptible as 293T cells, suggesting that cellular factors enhance the mNDK infection in 293T cells. By screening a cDNA expression library in HeLa cells, cystatin C was isolated as an enhancer of the mNDK infection. Because cathepsin B protease, a natural ligand of cystatin C, was upregulated in HeLa cells, we speculated that the high levels of cathepsin B activities were inhibitory to the CD4-independent infection and that cystatin C enhanced the infection by impairing the excessive cathepsin B activity. Consistent with this idea, pretreatment of HeLa cells with 125 µM of CA-074Me, a cathepsin B inhibitor, resulted in an 8-fold enhancement of the mNDK infectivity. Because cathepsin B is activated by low pH in acidic endosomes, we further examined the potential roles of endosomes in the CD4-independent infection. Suppression of endosome acidification or endocytosis by inhibitors or by an Eps15 dominant negative mutant reduced the infectivity of mNDK in which CD4-dependent infections were not significantly impaired. Taken together, these results suggest that endocytosis, endosomal acidification, and cathepsin B activity are involved in the CD4-independent entry of HIV-1

Time-resolved serial femtosecond crystallography reveals early structural changes in channelrhodopsin

X線自由電子レーザーを用いて、光照射によるチャネルロドプシンの構造変化の過程を捉えることに成功. 京都大学プレスリリース. 2021-03-26.Channelrhodopsins (ChRs) are microbial light-gated ion channels utilized in optogenetics to control neural activity with light . Light absorption causes retinal chromophore isomerization and subsequent protein conformational changes visualized as optically distinguished intermediates, coupled with channel opening and closing. However, the detailed molecular events underlying channel gating remain unknown. We performed time-resolved serial femtosecond crystallographic analyses of ChR by using an X-ray free electron laser, which revealed conformational changes following photoactivation. The isomerized retinal adopts a twisted conformation and shifts toward the putative internal proton donor residues, consequently inducing an outward shift of TM3, as well as a local deformation in TM7. These early conformational changes in the pore-forming helices should be the triggers that lead to opening of the ion conducting pore