Field-effect transistors assembled from functionalized carbon nanotubes

We have fabricated field effect transistors from carbon nanotubes using a novel selective placement scheme. We use carbon nanotubes that are covalently bound to molecules containing hydroxamic acid functionality. The functionalized nanotubes bind strongly to basic metal oxide surfaces, but not to silicon dioxide. Upon annealing, the functionalization is removed, restoring the electronic properties of the nanotubes. The devices we have fabricated show excellent electrical characteristics.Comment: 5 pages, 6 figure

Reversible Integration of Microfluidic Devices with Microelectrode Arrays for Neurobiological Applications

The majority of current state-of-the-art microfluidic devices are fabricated via replica molding of the fluidic channels into PDMS elastomer and then permanently bonding it to a Pyrex surface using plasma oxidation. This method presents a number of problems associated with the bond strengths, versatility, applicability to alternative substrates, and practicality. Thus, the aim of this study was to investigate a more practical method of integrating microfluidics which is superior in terms of bond strengths, reversible, and applicable to a larger variety of substrates, including microfabricated devices. To achieve the above aims, a modular microfluidic system, capable of reversible microfluidic device integration, simultaneous surface patterning and multichannel fluidic perfusion, was built. To demonstrate the system’s potential, the ability to control the distribution of A549 cells inside a microfluidic channel was tested. Then, the system was integrated with a chemically patterned microelectrode array, and used it to culture primary, rat embryo spinal cord neurons in a dynamic fluidic environment. The results of this study showed that this system has the potential to be a cost effective and importantly, a practical means of integrating microfluidics. The system’s robustness and the ability to withstand extensive manual handling have the additional benefit of reducing the workload. It also has the potential to be easily integrated with alternative substrates such as stainless steel or gold without extensive chemical modifications. The results of this study are of significant relevance to research involving neurobiological applications, where primary cell cultures on microelectrode arrays require this type of flexible integrated solution

The HOXB4 Homeoprotein Promotes the Ex Vivo Enrichment of Functional Human Embryonic Stem Cell-Derived NK Cells

Human embryonic stem cells (hESCs) can be induced to differentiate into blood cells using either co-culture with stromal cells or following human embryoid bodies (hEBs) formation. It is now well established that the HOXB4 homeoprotein promotes the expansion of human adult hematopoietic stem cells (HSCs) but also myeloid and lymphoid progenitors. However, the role of HOXB4 in the development of hematopoietic cells from hESCs and particularly in the generation of hESC-derived NK-progenitor cells remains elusive. Based on the ability of HOXB4 to passively enter hematopoietic cells in a system that comprises a co-culture with the MS-5/SP-HOXB4 stromal cells, we provide evidence that HOXB4 delivery promotes the enrichment of hEB-derived precursors that could differentiate into fully mature and functional NK. These hEB-derived NK cells enriched by HOXB4 were characterized according to their CMH class I receptor expression, their cytotoxic arsenal, their expression of IFNγ and CD107a after stimulation and their lytic activity. Furthermore our study provides new insights into the gene expression profile of hEB-derived cells exposed to HOXB4 and shows the emergence of CD34+CD45RA+ precursors from hEBs indicating the lymphoid specification of hESC-derived hematopoietic precursors. Altogether, our results outline the effects of HOXB4 in combination with stromal cells in the development of NK cells from hESCs and suggest the potential use of HOXB4 protein for NK-cell enrichment from pluripotent stem cells

Altered multisensory temporal integration in obesity

Eating is a multisensory behavior. The act of placing food in the mouth provides us with a variety of sensory information, including gustatory, olfactory, somatosensory, visual, and auditory. Evidence suggests altered eating behavior in obesity. Nonetheless, multisensory integration in obesity has been scantily investigated so far. Starting from this gap in the literature, we seek to provide the first comprehensive investigation of multisensory integration in obesity. Twenty male obese participants and twenty male healthy-weight participants took part in the study aimed at describing the multisensory temporal binding window (TBW). The TBW is defined as the range of stimulus onset asynchrony in which multiple sensory inputs have a high probability of being integrated. To investigate possible multisensory temporal processing deficits in obesity, we investigated performance in two multisensory audiovisual temporal tasks, namely simultaneity judgment and temporal order judgment. Results showed a wider TBW in obese participants as compared to healthy-weight controls. This holds true for both the simultaneity judgment and the temporal order judgment tasks. An explanatory hypothesis would regard the effect of metabolic alterations and low-grade inflammatory state, clinically observed in obesity, on the temporal organization of brain ongoing activity, which one of the neural mechanisms enabling multisensory integration

Etude de la transition globule-forme étirée des polyamines tertiaires partiellement quaternisées par diffusion centrale des rayons X

Q-P(TDAE) X bifunctional polybases are constituted of a poly[thioether] backbone carrying both pendent tertiary amine groups, and quaternary ammonium groups resulting from partial N-methylation (X %) of some of the tertiary amine groups. These macromolecules are soluble in water whatever the pH, in contrast to the non-methylated precursor. Members of the series with X ≤ 25, have revealed an unusual polyelectrolytic behaviour characterized by very low viscosity for total deprotonation of tertiary amine residues, linear variation of the reduced viscosity as a function of the apparent degree of protonation βa, and the presence of a plateau of pH in potentiometric titration curves (high buffering effect). In order to bear out the mechanism based on a globule-toextended coil cooperative conformational transition of the all-or-none type which has been proposed previously to account for the particular physico-chemical characteristics of Q-P(TDAE) X, SAXS was investigated of Q-P(TDAE) 19 salt-free aqueous solutions at various concentrations and states of protonation for two counter-ions (Cl- and Br-). All the I(s) = f(s) curves show a peak. For low degree of protonation, the peak is narrow and periodic oscillations are observed in the high |s| range. The radius of the scattering particles is evaluated from intrinsic viscosity, from the effective potential model regarding the homogeneous sphere, from the minima position of the SAXS curves and in the other hand by using the Porod's law. The différent values thus obtained are in good agreement (R ≃ 38 A for Br- and R ≃ 36 A for Cl-). For high degrees of protonation, the peak is larger and no oscillation was detected. The variations of the position |sm| of the maximum I(sm) with polymer concentration bears out the présence of an extended coil form (|sm| ∼ Cp-1/2). It is also shown that, in the high buffering zone, the experimental intensity curves for given βa values can be deduced directly from intensity curves corresponding to the extreme conformational forms according to the respective weights of these forms. Data bear out the partition of macromolecules in two populations at equilibrium.Les polybases bifonctionnelles Q-P(TDAE) X, sont constituées d'un squelette poly[thioéther] portant à la fois des groupements latéraux amine tertiaire et des groupements ammonium quaternaire obtenus par N-méthylation d'une partie (X %) des groupes amine tertiaire. Elles sont solubles dans l'eau quel que soit le pH, contrairement à la polyamine tertiaire précurseur. Les membres de la série ayant X ≤ 25, ont révélé un comportement polyélectrolytique inhabituel caractérisé notamment par une très faible viscosité à déprotonation totale des groupes amine tertiaire, une variation linéaire de la viscosité réduite en fonction du degré de protonation apparent βa et la présence d'un plateau de pH dans les courbes de titrage potentiométrique (effet tampon). Afin de confirmer le mécanisme de transition conformationnelle coopérative globule-forme étirée proposé précédemment pour rendre compte de ces caractéristiques particulières, l'intensité des rayons X diffusée aux petits angles a été mesurée dans l'eau en absence de sel pour des solutions de Q-P(TDAE) 19 à diverses concentrations et à divers états de protonation pour deux contre-ions (Cl- et Br-). Les courbes I(s) = f (s) présentent toutes un maximum. A faible protonation, le pic est étroit et des oscillations périodiques sont observées pour les grandes valeurs de |s |. Le rayon des particules diffusantes est évalué à partir de la viscosité intrinsèque, à partir d'un modèle de potentiel effectif pour des particules homogènes et à partir de la position des minima d'oscillations des courbes de diffusion et de la loi de Porod dans l'hypothèse d'un modèle de sphères dures. Les différentes valeurs obtenues sont en bon accord (R ≃ 38 A pour Br- et R ≃ 36 A pour Cl-). A forte protonation, le pic est plus large et aucune oscillation n'est détectée. Les déplacements de la position |Sm | du maximum I(Sm) en fonction de la concentration en polymère confirment la présence d'une forme étirée (| Sm|∼C-1/2). Il est également montré que, dans la zone du palier de pH, les courbes d'intensité diffusée à un degré de protonation apparent βa donné se déduisent directement des courbes d'intensité diffusée des formes extrêmes selon les poids relatifs de ces dernières. Ces résultats confirment l'existence d'un partage des macromolécules en deux populations en équilibre

Interactions between interoception and perspective-taking: Current state of research and future directions

Interoception, the sense of the physiological state of the body, and perspective-taking, the ability to take another's point of view, are two fundamental components contributing to our perception and interaction with the external world. However, whether the perception of our inner body influences how we perceive the external world and other people remains poorly understood. Here, we review recent behavioural and neuroimaging evidence investigating the links between dimensions of interoception (i.e., accuracy, sensibility and awareness) and perspective-taking (i.e., affective, cognitive and visual). So far, only a limited subset of these dimensions has been investigated together and the results suggest that interoceptive abilities may only interact with perspective-taking when embodied mental transformations are required. Furthermore, mainly the emotional aspects of perspective-taking are related to interoception, influencing the ability to empathise with others. Future research should systematically investigate the links between all dimensions of interoception and perspective-taking to provide full understanding of the specific role interoception has on how we perceive the world and take another's point of view

Before remodel-04

Main floor and second floor before the remodel.https://scholar.csl.edu/libraryreno/1033/thumbnail.jp

Small angle neutron and X-ray scattering study of the formation and structure of micelles of CTAB in formamide

Small angle neutron and X-ray scattering was used to study micellization of cetyltrimethylammonium bromide (CTAB) in partially deuterated or hydrogenated formamide from the absolute values of scattered intensities,). Highly charged aggregates of around 6 monomers were observed at CTAB concentrations above the cmc (2.8 % wt at 60 $^{\circ}$C). These aggregates along with spherical particles (2 nm radius) containing 29 monomers were consistently observed at concentrations above 8 %. These particles were considered to be micelles as they had similar structure, albeit of smaller size to those observed in water (2.7 nm, aggregation number 90). They also had a higher charge in formamide than in water (degree of ionization 0.55 in formamide and 0.14 in water). With increase in surfactant concentration, the micelles elongated, although the radius of the cylinders in the two dimensional hexagonal phase remained close to 2 nm. The importance of interactions of polar head with solvent molecules of high dipole moment and dielectric constant is discussed. The less spontaneous self-association of surfactant molecules in formamide than in water poses the problem of the cmc