Nanostructure and Magnetic Field Ordering in Aqueous Fe3O4 Ferrofluids: A Small-Angle Neutron Scattering Study

Despite the importance of reducing production costs, investigating the hierarchical nanostructure and magnetic field ordering of Fe3O4 ferrofluids is also important to improve its application performance. Therefore, we proposed an inexpensive synthesis method in producing the Fe3O4 ferrofluids and investigated their detailed nanostructure as the effect of liquid carrier composition as well as their magnetic field ordering. In the present work, the Fe3O4 ferrofluids were successfully prepared through a coprecipitation route using a central precursor of natural Fe3O4 from iron sand. The nanostructural behaviors of the Fe3O4 ferrofluids, as the effects of the dilution of the Fe3O4 particles with H2O as a carrier liquid, were examined using a small-angle neutron spectrometer (SANS). The Fe3O4 nanopowders were also prepared for comparison. A single lognormal spherical distribution and a mass fractal model were applied to fit the neutron scattering data of the Fe3O4 ferrofluids. The increasing carrier liquid composition of the fluids during dilution process was able to reduce the fractal dimension and led to a shorter length of aggregation chains. However, it did not change the size of the primary particles or building block (approximately 3.8 nm) of the Fe3O4 particles. The neutron scattering of the Fe3O4 ferrofluids under an external magnetic field in the range of 0 to 1 T exhibited in a standard way of anisotropic phenomenon originating from the nanostructural ordering of the Fe3O4 particles. On the other hand, the Fe3O4 powders did not show anisotropic scattering under an external field in the same range. Furthermore, the magnetization curve of the Fe3O4 ferrofluids and nanopowders exhibited a proper superparamagnetic character at room temperature with the respective saturation magnetization of 4.4 emu/g and 34.7 emu/g

Real Time Imaging of Human Progenitor Neurogenesis

Human neural progenitors are increasingly being employed in drug screens and emerging cell therapies targeted towards neurological disorders where neurogenesis is thought to play a key role including developmental disorders, Alzheimer’s disease, and depression. Key to the success of these applications is understanding the mechanisms by which neurons arise. Our understanding of development can provide some guidance but since little is known about the specifics of human neural development and the requirement that cultures be expanded in vitro prior to use, it is unclear whether neural progenitors obey the same developmental mechanisms that exist in vivo. In previous studies we have shown that progenitors derived from fetal cortex can be cultured for many weeks in vitro as undifferentiated neurospheres and then induced to undergo neurogenesis by removing mitogens and exposing them to supportive substrates. Here we use live time lapse imaging and immunocytochemical analysis to show that neural progenitors use developmental mechanisms to generate neurons. Cells with morphologies and marker profiles consistent with radial glia and recently described outer radial glia divide asymmetrically and symmetrically to generate multipolar intermediate progenitors, a portion of which express ASCL1. These multipolar intermediate progenitors subsequently divide symmetrically to produce CTIP2+ neurons. This 3-cell neurogenic scheme echoes observations in rodents in vivo and in human fetal slice cultures in vitro, providing evidence that hNPCs represent a renewable and robust in vitro assay system to explore mechanisms of human neurogenesis without the continual need for fresh primary human fetal tissue. Knowledge provided by this and future explorations of human neural progenitor neurogenesis will help maximize the safety and efficacy of new stem cell therapies by providing an understanding of how to generate physiologically-relevant cell types that maintain their identities when placed in diagnostic or transplantation environments

Autistic empathy toward autistic others.

自閉スペクトラム症がある方々による、自閉スペクトラム症がある方々に対する共感. 京都大学プレスリリーズ. 2014-11-06.Individuals with Autism Spectrum Disorder (ASD) are thought to lack self-awareness and to experience difficulty empathising with others. Although these deficits have been demonstrated in previous studies, most of the target stimuli were constructed for typically developing (TD) individuals. We employed judgment tasks capable of indexing self-relevant processing in individuals with and without ASD. Fourteen Japanese males and one Japanese female with high-functioning ASD (17-41 years of age) and 13 Japanese males and two TD Japanese females ( 22-40 years of age), all of whom were matched for age and full and verbal intelligence quotient scores with the ASD participants, were enrolled in this study. The results demonstrated that the ventromedial prefrontal cortex was significantly activated in individuals with ASD in response to autistic characters and in TD individuals in response to non-autistic characters. Whereas the frontal-posterior network between the ventromedial prefrontal cortex and superior temporal gyrus participated in the processing of non-autistic characters in TD individuals, an alternative network was involved when individuals with ASD processed autistic characters. This suggests an atypical form of empathy in individuals with ASD toward others with ASD

Directional Errors in Retention of a Pressure Control Skill as a Function of the Nature of an Interpolated Task

The present study examined directional error shifts (assimilation or contrast) in the reproduction of a criterion pressure control task (2kg) following either 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5kg and a noninterpolated pressure control task. Eight independent groups of subjects (N=120) were tested. The results showed that when an interpolated forces was greater in magnitude than the criterion one, the subjects produced a significantly smaller magnitude of force than the criterion one. These results supported the contrast effect and not the assimilation effect

Distribution of airway narrowing responses across generations and at branching points, assessed in vitro by anatomical optical coherence tomography

Background: Previous histological and imaging studies have shown the presence of variability in the degree of bronchoconstriction of airways sampled at different locations in the lung (i.e., heterogeneity). Heterogeneity can occur at different airway generations and at branching points in the bronchial tree. Whilst heterogeneity has been detected by previous experimental approaches, its spatial relationship either within or between airways is unknown.Methods: In this study, distribution of airway narrowing responses across a portion of the porcine bronchial tree was determined in vitro. The portion comprised contiguous airways spanning bronchial generations (#3-11), including the associated side branches. We used a recent optical imaging technique, anatomical optical coherence tomography, to image the bronchial tree in three dimensions. Bronchoconstriction was produced by carbachol administered to either the adventitial or luminal surface of the airway. Luminal cross sectional area was measured before and at different time points after constriction to carbachol and airway narrowing calculated from the percent decrease in luminal cross sectional area.Results: When administered to the adventitial surface, the degree of airway narrowing was progressively increased from proximal to distal generations (r = 0.80 to 0.98, P < 0.05 to 0.001). This 'serial heterogeneity' was also apparent when carbachol was administered via the lumen, though it was less pronounced. In contrast, airway narrowing was not different at side branches, and was uniform both in the parent and daughter airways.Conclusions: Our findings demonstrate that the bronchial tree expresses intrinsic serial heterogeneity, such that narrowing increases from proximal to distal airways, a relationship that is influenced by the route of drug administration but not by structural variations accompanying branching sites

Constraints on neutrino oscillation parameters from the measurement of day-night solar neutrino fluxes at Super-Kamiokande

A search for day-night variations in the solar neutrino flux resulting from neutrino oscillations has been carried out using the 504 day sample of solar neutrino data obtained at Super-Kamiokande. The absence of a significant day-night variation has set an absolute flux independent exclusion region in the two neutrino oscillation parameter space.Comment: 11 pages, 3 figures, submitted to PRL, single-spacin

Constraints on Neutrino Oscillations Using 1258 Days of Super-Kamiokande Solar Neutrino Data

We report the result of a search for neutrino oscillations using precise measurements of the recoil electron energy spectrum and zenith angle variations of the solar neutrino flux from 1258 days of neutrino-electron scattering data in Super-Kamiokande. The absence of significant zenith angle variation and spectrum distortion places strong constraints on neutrino mixing and mass difference in a flux-independent way. Using the Super-Kamiokande flux measurement in addition, two allowed regions at large mixing are found.Comment: 6 pages, 4 figures, submitted to PR

Study of Non-Standard Neutrino Interactions with Atmospheric Neutrino Data in Super-Kamiokande I and II

In this paper we study non-standard neutrino interactions as an example of physics beyond the standard model using atmospheric neutrino data collected during the Super-Kamiokande I(1996-2001) and II(2003-2005) periods. We focus on flavor-changing-neutral-currents (FCNC), which allow neutrino flavor transitions via neutral current interactions, and effects which violate lepton non-universality (NU) and give rise to different neutral-current interaction-amplitudes for different neutrino flavors. We obtain a limit on the FCNC coupling parameter, varepsilon_{mu tau}, |varepsilon_{mu tau}|<1.1 x 10^{-2} at 90%C.L. and various constraints on other FCNC parameters as a function of the NU coupling, varepsilon_{e e}. We find no evidence of non-standard neutrino interactions in the Super-Kamiokande atmospheric data.Comment: 12 Pages, 14 figures. To be submitted to Phys. Rev.