Exciton diffusion in air-suspended single-walled carbon nanotubes

Direct measurements of the diffusion length of excitons in air-suspended single-walled carbon nanotubes are reported. Photoluminescence microscopy is used to identify individual nanotubes and to determine their lengths and chiral indices. Exciton diffusion length is obtained by comparing the dependence of photoluminescence intensity on the nanotube length to numerical solutions of diffusion equations. We find that the diffusion length in these clean, as-grown nanotubes is significantly longer than those reported for micelle-encapsulated nanotubes.Comment: 4 pages, 4 figure

Gate-induced blueshift and quenching of photoluminescence in suspended single-walled carbon nanotubes

Gate-voltage effects on photoluminescence spectra of suspended single-walled carbon nanotubes are investigated. Photoluminescence microscopy and excitation spectroscopy are used to identify individual nanotubes and to determine their chiralities. Under an application of gate voltage, we observe slight blueshifts in the emission energy and strong quenching of photoluminescence. The blueshifts are similar for different chiralities investigated, suggesting extrinsic mechanisms. In addition, we find that the photoluminescence intensity quenches exponentially with gate voltage.Comment: 4 pages, 4 figure

Origin of structural and kinematical properties of the Small Magellanic Cloud

We investigate structural, kinematical, and chemical properties of stars and gas in the Small Magellanic Cloud (SMC) interacting with the Large Magellanic Cloud (LMC) and the Galaxy based on a series of self-consistent chemodynamical simulations. We adopt a new "dwarf spheroidal model" in which the SMC initially has both old stars with a spherical spatial distribution and an extended HI gas disk. We mainly investigate SMC's evolution for the last 3 Gyr within which the Magellanic stream (MS) and the Magellanic bridge (MB) can be formed as a result of the LMC-SMC-Galaxy interaction. Our principal results, which can be tested against observations, are as follows. The final spatial distribution of the old stars projected onto the sky is spherical even after the strong LMC-SMC-Galaxy interaction, whereas that of the new ones is significantly flattened and appears to form a bar structure. Old stars have the line-of-sight velocity dispersion (sigma) of ~ 30 km/s and slow rotation with the maximum rotational velocity (V) of less than slow rotation with the maximum rotational velocity (V) of less than 20 km/s and show asymmetry in the radial profiles. New stars have a smaller sigma than old ones and a significant amount of rotation (V/sigma >1). HI gas shows velocity dispersions of sigma = 10-40 km/s a high maximum rotational velocity (V ~ 50 km/s), and the spatial distribution similar to that of new stars. The new stars with ages younger than 3 Gyr show a negative metallicity gradient in the sense that more metal-rich stars are located in the inner regions of the SMC.Comment: 21 pages, 21 figures (5 color), accepted by PAS

Evaluation of carbon dioxide absorption by amine based absorbent

AbstractToshiba has developed amine based aqueous solution (Toshiba solvent 1, TS-1) that can significantly reduce CO2 regeneration energy compared with general 30 wt% monoethanolamine (MEA) aqueous solution and reported the results of the pilot plant of 10 t- CO2/day recovery from the flue gas of a coal- fired power plant. In order to reduce the CO2 regeneration energy further, we have developed new hindered amine based absorbent, Absorbent-A.In the present work, Absorbent-A was evaluated for CO2 absorption properties by laboratory scale apparatus. Absorbent-A was found to have the high CO2 absorption capacity and the low reaction heat. Furthermore, the CO2 regeneration energy of Absorbent-A was 45% less than that of general 30 wt% MEA aqueous solution.In future, we will additionally evaluate Absorbent-A in order to test in the pilot plant

Novel application of yeast molecular display system to analysis of protein functions

This review fundamentally covers the functional analysis of proteins and the preparation of modified proteins for the creation of novel functions using a yeast molecular display system as a molecular tool. Yeast molecular display is a genetic technique of producing proteins or peptides on the yeast cell surface, such as the cell wall or cell membrane. In this review, recent studies on the yeast molecular display system in the field of not only applied studies but also fundamental studies are described with illustrations

Measurements of laser-hole boring into overdense plasmas using x-ray laser refractometry(invited)

Copyright 1999 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Review of Scientific Instruments, 70(1), 543-548, 1986 and may be found at http://dx.doi.org/10.1063/1.114938

TDP1 deficiency sensitizes human cells to base damage via distinct topoisomerase I and PARP mechanisms with potential applications for cancer therapy

Base damage and topoisomerase I (Top1)-linked DNA breaks are abundant forms of endogenous DNA breakage, contributing to hereditary ataxia and underlying the cytotoxicity of a wide range of anti-cancer agents. Despite their frequency, the overlapping mechanisms that repair these forms of DNA breakage are largely unknown. Here, we report that depletion of Tyrosyl DNA phosphodiesterase 1 (TDP1) sensitizes human cells to alkylation damage and the additional depletion of apurinic/apyrimidinic endonuclease I (APE1) confers hypersensitivity above that observed for TDP1 or APE1 depletion alone. Quantification of DNA breaks and clonogenic survival assays confirm a role for TDP1 in response to base damage, independently of APE1. The hypersensitivity to alkylation damage is partly restored by depletion of Top1, illustrating that alkylating agents can trigger cytotoxic Top1-breaks. Although inhibition of PARP activity does not sensitize TDP1-deficient cells to Top1 poisons, it confers increased sensitivity to alkylation damage, highlighting partially overlapping roles for PARP and TDP1 in response to genotoxic challenge. Finally, we demonstrate that cancer cells in which TDP1 is inherently deficient are hypersensitive to alkylation damage and that TDP1 depletion sensitizes glioblastoma-resistant cancer cells to the alkylating agent temozolomide

Conditional deletion of Bmpr1a in differentiated osteoclasts increases osteoblastic bone formation, increasing volume of remodeling bone in mice

Bone undergoes remodeling consisting of osteoclastic bone resorption followed by osteoblastic bone formation throughout life. Although the effects of bone morphogenetic protein (BMP) signals on osteoblasts have been studied extensively, the function of BMP signals in osteoclasts has not been fully elucidated. To delineate the function of BMP signals in osteoclasts during bone remodeling, we deleted BMP receptor type IA ( Bmpr1a ) in an osteoclast‐specific manner using a knock‐in Cre mouse line to the cathepsin K locus ( Ctsk Cre/+ ;Bmpr1a flox/flox , designated as Bmpr1a ΔOc/ΔOc ). Cre was specifically expressed in multinucleated osteoclasts in vivo. Cre‐dependent deletion of the Bmpr1a gene occurred at 4 days after cultivation of bone marrow macrophages obtained from Bmpr1a ΔOc/ΔOc with RANKL. These results suggested that Bmpr1a was deleted after formation of osteoclasts in Bmpr1a ΔOc/ΔOc mice. Expression of bone‐resorption markers increased, thus suggesting that BMPRIA signaling negatively regulates osteoclast differentiation. Trabeculae in tibia and femurs were thickened in 3.5‐, 8‐, and 12‐week‐old Bmpr1a ΔOc/ΔOc mice. Bone histomorphometry revealed increased bone volume associated with increased osteoblastic bone‐formation rates (BFR) in the remodeling bone of the secondary spongiosa in Bmpr1a ΔOc/ΔOc tibias at 8 weeks of age. For comparison, we also induced an osteoblast‐specific deletion of Bmpr1a using Col1a1‐Cre. The resulting mice showed increased bone volume with marked decreases in BFR in tibias at 8 weeks of age. These results indicate that deletion of Bmpr1a in differentiated osteoclasts increases osteoblastic bone formation, thus suggesting that BMPR1A signaling in osteoclasts regulates coupling to osteoblasts by reducing bone‐formation activity during bone remodeling. © 2011 American Society for Bone and Mineral ResearchPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87086/1/477_ftp.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/87086/2/jbmr_477_sm_SupplData.pd

Effects of sports participation on psychiatric symptoms and brain activations during sports observation in schizophrenia

Weight gain has been identified as being responsible for increased morbidity and mortality rates of schizophrenia patients. For the management of weight gain, exercise is one of the most acknowledged interventions. At the same time, exercise and sports have been recognized for their positive impact on psychiatric symptoms of schizophrenia. However, the neurobiological basis for this remains poorly understood. We aimed to examine the effect of sports participation on weight gain, psychiatric symptoms and brain activation during sports observation in schizophrenia patients. Thirteen schizophrenia patients who participated in a 3-month program, including sports participation and 10 control schizophrenia patients were studied. In both groups, body mass index (BMI), Positive and Negative Syndrome Scale (PANSS), and brain activation during observation of sports-related actions measured by functional magnetic resonance imaging were accessed before and after a 3-month interval. BMI and general psychopathology scale of PANSS were significantly reduced in the program group but not in the control group after a 3-month interval. Compared with baseline, activation of the body-selective extrastriate body area (EBA) in the posterior temporal-occipital cortex during observation of sports-related actions was increased in the program group. In this group, increase in EBA activation was associated with improvement in the general psychopathology scale of PANSS. Sports participation had a positive effect not only on weight gain but also on psychiatric symptoms in schizophrenia. EBA might mediate these beneficial effects of sports participation. Our findings merit further investigation of neurobiological mechanisms underlying the therapeutic effect of sports for schizophrenia

Five-point Likert scaling on MRI predicts clinically significant prostate carcinoma

Background: To clarify the relationship between the probability of prostate cancer scaled using a 5-point Likert system and the biological characteristics of corresponding tumor foci. Methods: The present study involved 44 patients undergoing 3.0-Tesla multiparametric MRI before laparoscopic radical prostatectomy. Tracing based on pathological and MRI findings was performed. The relationship between the probability of cancer scaled using the 5-point Likert system and the biological characteristics of corresponding tumor foci was evaluated. Results: A total of 102 tumor foci were identified histologically from the 44 specimens. Of the 102 tumors, 55 were assigned a score based on MRI findings (score 1: n = 3; score 2: n = 3; score 3: n = 16; score 4: n = 11 score 5: n = 22), while 47 were not pointed out on MRI. The tracing study revealed that the proportion of >0.5 cm3 tumors increased according to the upgrade of Likert scores (score 1 or 2: 33 %; score 3: 68.8 %; score 4 or 5: 90.9 %, χ2 test, p 7 also increased from scale 2 to scale 5 (scale 2: 0 %; scale 3: 56.3 %; scale 4: 72.7 %; 5: 90.9 %, χ2 test, p = 0.0001). On using score 3 or higher as the threshold of cancer detection on MRI, the detection rate markedly improved if the tumor volume exceeded 0.5 cm3 (<0.2 cm3: 10.3 %; 0.2-0.5 cm3: 25 %; 0.5-1.0 cm3: 66.7 %; 1.0 < cm3: 92.1 %). Conclusions: Each Likert scale favobably reflected the corresponding tumor’s volume and Gleason score. Our observations show that “score 3 or higher” could be a useful threshold to predict clinically significant carcinoma when considering treatment options