215 research outputs found
Chiral Algebras of (0, 2) Models
No full textSigma models with (0, 2) supersymmetry in two dimensions possess quasi-topological sectors characterized by chiral algebras. In this thesis, we study these chiral algebras and explore their nonperturbative aspects. The chiral algebras of (0, 2) models emerge when one considers the cohomology of local operators with respect to one of the supercharges, and provide infinite-dimensional generalizations of the chiral rings of (2, 2) models. Perturbatively, they enjoy rich math-ematical structures described by sheaves of chiral differential operators. Nonperturba-tively, however, they vanish completely for certain (0, 2) models with no left-moving fermions. Examples include the models in which the target spaces are the complete flag manifolds of compact semisimple Lie groups. The vanishing of the chiral algebra of a (0, 2) model implies that supersymmetry is spontaneously broken in the model, which in turn suggests that no harmonic spinors exist on the loop space of the target space. We analyze this supersymmetry breaking using holomorphic Morse theory on the loop space in the case where the target space is CP1. As expected, we find that instantons interpolate between pairs of perturbative supersymmetric states, thereby lifting them out of the supersymmetric spectrum
Abstract 774: Notch pathway activation predicts resistance to bevacizumab therapy in glioblastoma
No full textAbstract
Glioblastoma, the most common adult glioma, is associated with a dismal prognosis. Treatment with bevacizumab has not significantly prolonged overall patient survival times. Glioblastoma resistance to angiogenesis inhibitors is attributed to multiple interacting mechanisms. We have thus embarked on a comprehensive effort to detecting expression signatures that are associated with response to the therapy and these signatures may allow prospective selection of patients with high likelihood of responding to therapy. Notch signaling pathway is an evolutionarily conserved pathway that plays an important role in multiple cellular and developmental processes including cell fate decision, differentiation, proliferation, survival, angiogenesis and migration. Analysis of The Cancer Genome Atlas expression dataset identified a group (43.9%) of tumors with proneural signature showing high Notch pathway activation. In this study, we compared CD133, Notch, and VEGF expressions in histological sections of primary and recurrent glioblastomas after radiotherapy and chemotherapy. Tumor samples were collected from 27 patients at the time of tumor recurrence. We used immunohistochemical techniques to compare expression of CD133, Notch-1 and VEGF. Expressions of CD133-, Notch-1-, and VEGF-positive glioma cells were higher in recurrent glioblastoma after radiotherapy and chemotherapy. To determine the clinical importance of Notch-1 expression in glioblastoma, we analyzed 15 patients who had received bevacizumab therapy followed by a second surgery at recurrence. OS was significantly longer in cases with Notch-1 negativity (8.8 months) than in those with Notch-1 positivity (6.8 months). Electron microscopic observation of two autopsy cases revealed the effects of blood vessel normalization in Notch-1 positive glioblastoma. Electron microscopic images confirmed the presence of pericytes surrounding the vascular endothelium. Autopsied tumors exhibited marked proliferation of Notch-1 and VEGF positive cells around vessels. In tumor angiogenesis, vascular endothelial growth factor and Notch signaling induce sprouting angiogenesis and recruitment of vascular endothelial cells such as tip cells, stalk cells, and phalanx cells. Fully mature phalanx cells are in close contact with pericytes. These findings indicate that bevacizumab treatment promotes vascular normalization by recruiting mature pericytes and associated with resistance to bevacizumab therapy in glioblastoma with high Notch pathway activation.
Citation Format: Norihiko Saito, Kazuya Aoki, Nozomi Hirai, Satoshi Fujita, Junya Iwama, Masashi Ikota, Haruo Nakayama, Morito Hayashi, Keisuke Ito, Takatoshi Sakurai, Satoshi Iwabuchi. Notch pathway activation predicts resistance to bevacizumab therapy in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 774. doi:10.1158/1538-7445.AM2017-774</jats:p
EPR spectra of type 3 copper centers in Rhus vernicifera laccase and Cucumis sativus ascorbate oxidase
No full text
Multisensory Information Facilitates Reaction Speed by Enlarging Activity Difference between Superior Colliculus Hemispheres in Rats
No full textAnimals can make faster behavioral responses to multisensory stimuli than to unisensory stimuli. The superior colliculus (SC), which receives multiple inputs from different sensory modalities, is considered to be involved in the initiation of motor responses. However, the mechanism by which multisensory information facilitates motor responses is not yet understood. Here, we demonstrate that multisensory information modulates competition among SC neurons to elicit faster responses. We conducted multiunit recordings from the SC of rats performing a two-alternative spatial discrimination task using auditory and/or visual stimuli. We found that a large population of SC neurons showed direction-selective activity before the onset of movement in response to the stimuli irrespective of stimulation modality. Trial-by-trial correlation analysis showed that the premovement activity of many SC neurons increased with faster reaction speed for the contraversive movement, whereas the premovement activity of another population of neurons decreased with faster reaction speed for the ipsiversive movement. When visual and auditory stimuli were presented simultaneously, the premovement activity of a population of neurons for the contraversive movement was enhanced, whereas the premovement activity of another population of neurons for the ipsiversive movement was depressed. Unilateral inactivation of SC using muscimol prolonged reaction times of contraversive movements, but it shortened those of ipsiversive movements. These findings suggest that the difference in activity between the SC hemispheres regulates the reaction speed of motor responses, and multisensory information enlarges the activity difference resulting in faster responses.Japan. Ministry of Education, Culture, Sports, Science and Technology (Grant-in-Aid for Scientific Research on Priority Areas (Molecular Brain Science))Japan. Ministry of Education, Culture, Sports, Science and Technology (Grant-in-Aid for Young Scientists)Japan. Science and Technology Agency (CREST Program
Impact of polymer formulations on neointimal proliferation after Zotarolimus-eluting stent with different polymers: Insights from the RESOLUTE Trial
No full textBackground—Polymer formulation may affect the efficacy of drug-eluting stents. Resolute, Endeavor, and ZoMaxx are zotarolimus-eluting stents with different stent platforms and different polymer coatings and have been tested in clinical trials. The aim of this analysis was to compare the efficacy of zotarolimus-eluting stents with different polymers. Methods and Results—Data were obtained from the first-in man trial or first randomized trials of each stent, The Clinical RESpOnse EvaLUation of the MedTronic Endeavor CR ABT-578 Eluting Coronary Stent System in De Novo Native Coronary Artery Lesions (RESOLUTE), Randomized Controlled Trial to Evaluate the Safety and Efficacy of the Medtronic AVE ABT-578 Eluting Driver Coronary Stent in De Novo Native Coronary Artery Lesions (ENDEAVOR II), and ZoMaxx I trials. Follow-up intravascular ultrasound analyses (8 to 9 months of follow-up) were possible in 353 patients (Resolute: 88, Endeavor: 98, ZoMaxx: 82, Driver: 85). Volume index (volume/stent length) was obtained for vessel, stent, lumen, peristent plaque, and neointima. Cross-sectional narrowing was defined as neointimal area divided by stent area (%). Neointima-free frame ratio was calculated as the number of frames without intravascular ultrasound–detectable neointima divided by the total number of frames within the stent. At baseline, vessel, lumen, and peristent plaque volume index were not significantly different among the 4 stent groups. At follow-up, percent neointimal obstruction was significantly lower in Resolute compared with Endeavor, ZoMaxx, and Driver (Resolute: 3.7±4.0, Endeavor: 17.5±10.1, ZoMaxx: 14.6±8.1, Driver: 29.4±17.2%; P<0.001). Greater maximum cross-sectional narrowing and higher neointima-free frame ratio, suggesting less neointimal coverage, were observed in Resolute compared with other stent groups. Multiple regression analysis confirmed that the biodurable polymer used in Resolute independently correlated with neointimal suppression among 3 zotarolimus-eluting stents. Conclusions—The different polymer formulations significantly affect the relative amount of neointima for zotarolimus-eluting stents.Katsuhisa Waseda, Junya Ako, Masao Yamasaki, Tomomi Koizumi, Ryota Sakurai, Yoichiro Hongo, Bon-Kwon Koo, John Ormiston, Stephen G. Worthley, Robert J. Whitbourn, Darren L. Walters, Ian T. Meredith, Peter J. Fitzgerald and Yasuhiro Hond
Novel CO2 Selective Membranes for CO2 Control in Space Station and Space Suit
No full textTucson, ArizonaThe 44th International Conference on Environmental Systems was held in Tuscon, Arizona, USA on 13 July 2014 through 17 July 2014.Osamu Okada, Renaissance Energy Research Corporation, JapanMasaaki Teramoto, Renaissance Energy Research Corporation, JapanTamotsu Nonouchi, Renaissance Energy Research Corporation, JapanNobuaki Hanai, Renaissance Energy Research Corporation, JapanJunya Miyata, Renaissance Energy Research Corporation, JapanYasato Kiyohara, Renaissance Energy Research Corporation, JapanMasato Sakurai, Japan Aerospace Exploration Agency, JapanFor the CO2 control in the space station, attention has been mainly paid to the adsorption method. One of the alternatives to this method is the separation using membranes, which is a simple continuous system with low energy consumption and no capacity limit since CO2 absorption at the feed side of the membrane and desorption at the permeate side occur simultaneously. In order to apply membranes for the CO2 removal in space stations and also in space suits, development of membranes with extremely high CO2 selectivity over O2 and N2 is required for minimizing the O2 and N2 losses. In the present work, we developed several types of CO2 selective facilitated transport membranes. These are gel-type membranes supported on microporous membranes. The gel layer contains a CO2 carrier, which enhances CO2 permeability, and also an additive, which improves the permeation characteristics. Typical membrane performances observed at low CO2 partial pressures (0.7kPa) and room temperature are as follows. CO2 permeance: 1.23104 1.71104 Ncm3 cm-2 s-1 cmHg-1 (4.1105 5.7105 mol m-2 s-1 kPa-1), CO2/N2 selectivity: 570013700, which is much larger than those reported so far. CO2/O2 selectivity was about half the CO2/N2 selectivity. The performance of membrane module, in which the developed membranes are supposed to be used, was estimated when the module is applied to space stations and space suits. It was found that the mol fraction of CO2 recovered from the permeate side of the membrane is higher than 0.96 (dry basis), which suggests very small O2 and N2 losses. When this membrane is applied to a space suit, the membrane area and volume of the membrane module required for removing CO2 at the rate 2.23 kg/day were approximately estimated as 31.6 m2 and 16 L, respectively. The membrane module works also for removing water vapor from space suits
Subjective decision threshold for accurate visual detection performance in rats
No full textAbstractThe dissociation between a subjective-criterion performance and forced performance in a sensory detection can provide critical insights into the neural correlates of sensory awareness. Here, we established a behavioral task for rats to test their spatial-visual cue detection ability, using a two alternative choice task with and without a third choice option where animals get rewards only in the objective absence of a visual cue. In the trials without the third option, spatial choice accuracy decreased from near perfect to near chance levels as the visual cue brightness decreased. In contrast, with the third option, the rats exhibited >90% spatial choice accuracy regardless of the cue brightness. The rats chose the third choice option less frequently when the cue was brighter, suggesting that rats have a generalized strategy to make spatial choices only when their internal detection criterion is met. Interestingly, even when the animals chose the third option, they could still significantly and correctly choose the direction of the visual stimuli if they were forced. Our data suggest that the rats’ variable detection performance with identical set of stimuli is derived from stochastic processing of visual signals with a certain internal detection threshold rather than general motivational threshold.</jats:p
Habitar el suelo. Aproximaciones estéticas hacia un habitar en relación
No full textThis text analyzes different contemporary architectural and sculptural materializations distinguishable because of the relational and contingent approach to all that surrounds us. From a sensitive approach and articulation towards what coexists, the spatial configurations exhibited here are an example of a way of doing, of an ethic and a technique, which try to inhabit this world in relation. This is perceptible in the approach and listening to the surroundings of Junya Ishigami’s architecture or in the configuration next to the things of Josu Bilbao’s floor sculpture. They are aesthetic configurations that expose, rescuing Judith Butler’s words, the irremediably relational and contingent condition of our existence. And from the manifest interdependence towards what surrounds and conditions us, these configurations are an example of what Adriana Cavarero proposes as "inclined geometry". This author understands inclination as an approach that, appearing outside itself, tends to the outside, in manifest structural interdependence of the subject towards that which coexists. This text exposes that inclined geometry through the spatial configurations of Junya Ishigami, Ryue Nishizawa, Gordon Matta-Clark and Josu Bilbao, as a possibility of inhabiting an unstable world.; Este texto analiza diferentes materializaciones arquitectónicas y escultóricas contemporáneas que se distinguen por un acercamiento relacional y contingente hacia todo aquello que nos rodea. Desde un acercamiento y articulación sensible hacia lo que coexiste, las configuraciones espaciales expuestas aquí son muestra de una manera de hacer, de una ética y una técnica, que tratan de habitar este mundo en relación. Eso es perceptible en el acercamiento y escucha hacia el entorno de la arquitectura de Junya Ishigami o en la configuración junto a las cosas de la escultura de suelo de Josu Bilbao. Son configuraciones estéticas que exponen, rescatando las palabras de Judith Butler, el carácter irremediablemente relacional y contingente de nuestra existencia. Y desde la interdependencia manifiesta hacia aquello que nos rodea y condiciona, estas configuraciones son ejemplo de lo que Adriana Cavarero propone como "geometría inclinada". Esta autora entiende por inclinación un acercarse que, asomándose fuera de sí, tiende al exterior, en manifiesta interdependencia estructural del sujeto hacia aquello con lo que coexiste. En este texto se expone esa geometría inclinada a través de las configuraciones espaciales de Junya Ishigami, Ryue Nishizawa, Gordon Matta-Clark y Josu Bilbao, como posibilidad de habitar un mundo inestable
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