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Much progress has been made in the nanoscale analysis of nanostructures, while the mapping of key charge transport properties such as a carrier mobility remains a challenge, especially for one-dimensional systems. Here, we report the nanoscale mapping of carrier mobilities in carbon nanotube (CNT) networks and show that charge transport behaviors varied depending on network structures. In this work, the spatial distribution of localized charge transport properties such as mobilities and charge trap densities in CNT networks were mapped via a scanning noise microscopy. The mobility map was obtained from the conductivity maps measured at different back-gate biases, showing up to two orders of mobility variations depending on localized network structures. Furthermore, from the maps, correlations between mobility/conductivity and charge trap density were analyzed to determine charge transport mechanisms. In metallic CNT networks, the regions with rather

This study explored the association between informal support (positive/negative) and three formal services (police, legal, and domestic violence services) among battered women and to examine the fa...

We mapped the nanoscale reduction of resistivity and noise source activities induced by metallic single walled carbon nanotubes (m-SWCNTs) embedded in gold thin films. In this method, current and noise maps of m-SWCNTs/gold hybrid thin films were recorded using a conducting probe in contact with the surface, and the maps were utilized to estimate the nanoscale variation of resistivity (ρ) and the density distribution of noise sources (Neff) generating electrical noises in the hybrid thin film. The m-SWCNTs/gold hybrid thin films with a 5 nm thick gold layer exhibited 300% improved conductivity compared to that of pristine gold thin films. Additionally, the regions with embedded m-SWCNTs showed significantly reduced noise source densities compared with pristine gold film regions. These results clearly show that embedded m-SWCNTs improve the conductivity and reduce electrical noises of metallic electrodes. Interestingly, we observed that the ρ and the Neff on both m-SWCNTs/gold hybrid and pristine gold regions exhibited a scaling behavior of ρ ∝ Neff0.5, implying the hopping charge conduction and noise characteristics of m-SWCNTs/gold hybrid films. Our works can be a useful guideline for the development of high performance electrodes based on CNTs.

Background Dysfunction in peripheral and neural structure with spastic cerebral palsy (CP) causes impaired performance and stability of various behaviors. Recent progress of quantification methods for the stability properties, which is based on the uncontrolled manifold hypothesis, has been applied to various neurological disorders. A prior study revealed that the ability for purposeful regulation of stability properties is weakened with CP during finger and hand actions. Successive regulation of stability properties is crucial for human locomotion; therefore, it is imperative to quantify the changes in the intersegmental coordination as to the stable performance in CP individuals during gait. Research question We hypothesized that (1) Spastic CP group will show smaller step length and gait velocity with larger variability, and (2) Spastic CP group will show no changes in average stability indices for both the COM and head position stabilization, while the smaller difference between stable and unstable posture during the gait cycle. Methods Whole-body kinematic data during walking were collected from CP and control subjects. Step length, velocity, and coefficient of variation (CV) were calculated as spatiotemporal parameters. We quantified the intersegmental stability index in time-series during gait for the stabilization of the whole-body COM and head position. Results The CP subjects showed smaller step length and velocity with larger CV than the controls. However, the CP group showed a significantly less difference in the stability indices between the single- and double-limb support phases as compared to the controls for both the COM and head position stabilization. Significance Present study is the first to document the quantification of changing intersegmental stability in the spastic CP during locomotion. The dysfunction of intentional modulation of stability properties in CP individuals may be a more common problem, which is not limited to a specific body effector.

A bioelectronic nose device based on micelle-stabilized olfactory receptors is developed for the selective discrimination of a butter flavor substance in commercial fermented alcoholic beverages. In this work, we have successfully overexpressed ODR-10, a type of olfactory receptor, from Caenorhabditis elegans using a bacterial expression system at a low cost and high productivity. The highly-purified ODR-10 was stabilized in micelle structures, and it was immobilized on a carbon nanotube field-effect transistor to build a bioelectronic nose for the detection of diacetyl, a butter flavor substance, via the specific interaction between diacetyl and ODR-10. The bioelectronic nose device can sensitively detect diacetyl down to 10 fM, and selectively discriminate it from other substances. In addition, this sensor could directly evaluate diacetyl levels in a variety of real fermented alcoholic beverages such as beer, wine, and makgeolli (fermented Korean wine), while the sensor did not respond to soju (Korean style liquor without diacetyl). In this respect, our sensor should be a powerful tool for versatile food industrial applications such as the quality control of alcoholic beverages and foods.

A bioelectronic skin device based on nociceptive ion channels in nanovesicles is developed for the detection of chemical cold-pain stimuli and cold environments just like human somesthetic sensory systems. The human transient receptor potential ankyrin 1 (hTRPA1) is involved in transmission and modulation of cold-pain sensations. In the bioelectronic skin, the nanovesicles containing the hTRPA1 nociceptive ion channel protein reacts to cold-pain stimuli, and it is electrically monitored through carbon nanotube transistor devices based on floating electrodes. The bioelectronic skin devices sensitively detect chemical cold-pain stimuli like cinnamaldehyde at 10 fm, and selectively discriminate cinnamaldehyde among other chemical stimuli. Further, the bioelectronic skin is used to evaluate the effect of cold environments on the response of the hTRPA1, finding that the nociceptive ion channel responds more sensitively to cinnamaldehyde at lower temperatures than at higher temperatures. The bioelectronic skin device could be useful for a basic study on somesthetic systems such as cold-pain sensation, and should be used for versatile applications such as screening of foods and drugs.

A method is developed to directly map nanoscale "noise-source switching" phenomena during the optoelectronic switching of phase-separated polymer nanocomposites of tetrathiafulvalene (TTF) and phenyl-C61 -butyric acid methyl ester (PCBM) molecules dispersed in a polystyrene (PS) matrix. In the method, electrical current and noise maps of the nanocomposite film are recorded using a conducting nanoprobe, enabling the mapping of a conductivity and a noise-source density. The results provide evidence for a repeated modulation in noise sources, a "noise-source switching," in each stage of a switching cycle. Interestingly, when the nanocomposite is "set" by a high bias, insulating PS-rich phases shows a drastic decrease in a noise-source density which becomes lower than that of conducting TTF-PCBM-rich phases. This can be attributed to a trap filling by charge carriers generated from a TTF (donor)-PCBM (acceptor) complex. In addition, when the film is exposed to UV, an optical switching occurs due to chemical reactions which lead to irreversible changes on the noise-source density and conductivity. The method provides a new insight on noise-source activities during the optoelectronic switching of polymer nanocomposites and thus can be a powerful tool for basic noise research and applications in organic memory devices.

Enzyme/substrate pairs, such as β-galactosidase with chromogenic x-gal substrate, are widely used as reporters to monitor biological events, but there is still a requirement for new reporter systems, which may be orthogonal to existing systems. Here, we focused on azoreductase (AzoR). We designed and synthesized a library of azo-rhodamine derivatives as candidate fluorogenic substrates. These derivatives were nonfluorescent, probably due to ultrafast conformational change around the N═N bond after photoexcitation. We found that AzoR-mediated reduction of the azo bond of derivatives bearing an electron-donating group on the azobenzene moiety was followed by nonenzymatic cleavage to afford highly fluorescent 2-methyl-rhodamine green (2-Me RG), which was well retained in cells. We show that the AzoR/compound 9 reporter system can detect azoreductase-expressing live cells at the single cell level.

The study examined perceptions of elder mistreatment (EM) and help-seeking intentions in two older Korean cohorts—residents in Korea (n = 124) and Korean immigrants (n = 124) in the United States, recruited using a quota sampling strategy. A mixed method survey utilized four hypothetical scenarios of physical, financial, and psychological abuse and neglect. A majority of participants perceived physical, financial, and psychological abuse scenarios as EM but not the neglect scenario. Multivariate analysis showed strong association between perception of mistreatment and help-seeking intention in the Korea-based cohort for all types of EM. In the immigrant cohort, help-seeking intention was associated with only the physical abuse vignette. The results suggest a need for culturally sensitive, type-specific EM interventions and education and policies on elder neglect in both countries.

Child welfare professionals are expected to promptly assess the current safety and future risks of children reported to them. Developing more accurate assessment methods has been a growing concern in child welfare. The presence of domestic violence and children's exposure to it are factors that have been included in many current risk assessment models used by child welfare professionals. An online survey of 152 child welfare professionals was conducted in twenty counties in one midwestern state. Professionals reported on the importance of (a) types of violence in a child's home and (b) the child's level of involvement in that violence; they also responded to how two hypothetical scenarios of child exposure to and involvement in violence would affect their decision making. The results provide insight into how child welfare professionals assess child exposure and involvement in domestic violence as a perceived risk and guidance on the training needs of these professionals.

The leucine-rich repeat kinase 2 (LRRK2) has been identified as the defective gene at the PARK8 locus causing the autosomal dominant form of Parkinson's disease (PD). Although several LRRK2 mutations were found in familial as well as sporadic PD patients, its physiological functions are not clearly defined. In this study, using yeast two-hybrid screening, we report the identification of Rab5b as an LRRK2-interacting protein. Indeed, our GST pull down and co-immunoprecipitation assays showed that it specifically interacts with LRRK2. In addition, subcellular fractionation and immunocytochemical analyses confirmed that a fraction of both proteins co-localize in synaptic vesicles. Interestingly, we found that alteration of LRRK2 expression by either overexpression or knockdown of endogenous LRRK2 in primary neuronal cells significantly impairs synaptic vesicle endocytosis. Furthermore, this endocytosis defect was rescued by co-expression of functional Rab5b protein, but not by its inactive form. Taken together, we propose that LRRK2, in conjunction with its interaction with Rab5b, plays an important role in synaptic function by modulating the endocytosis of synaptic vesicles.

This article describes the development and testing of the psychometric properties of a self-administered Child Exposure to Domestic Violence (CEDV) Scale. The 42-item CEDV was systematically developed using both pre-existing and newly developed items and subsequently subjected to a review and revision by an international panel of experts to establish face validity. After initial pilot testing, the CEDV was administered to 65 children, ages 10 to 16 years of age, who were receiving services from several domestic violence prevention organizations. The measure was administered concurrently with the Things I ' ve Seen and Heard measure of violence exposure to establish convergent validity and again one week later to establish test–retest reliability. The CEDV appears to be a valid and reliable measure of the level of exposure to domestic violence from a child's perspective. The authors discuss potential uses of this scale and the development of resources to support the use of the measure, including an online version of the scale.

Dynamic membrane remodeling during intracellular trafficking is controlled by the intricate interplay between lipids and proteins. BAR domains are modules that participate in endocytic processes by binding and deforming the lipid bilayer. Sorting nexin 9 (SNX9), which functions in clathrin-mediated endocytosis, contains a BAR domain, however, the properties of this domain are not well understood. Here we show that SNX9 shares many properties with other BAR domain-containing proteins, such as amphiphysin and endophilin. SNX9 is able to deform the plasma membrane, as well as liposomes, into narrow tubules and recruit N-WASP and dynamin 2 to these tubules via its SH3 domain. SNX9-induced tubulation is antagonized by N-WASP and dynamin 2 while it is enhanced by perturbation of actin dynamics. However, SNX9 also has several unique properties. The tubulating activity requires the BAR and PX domains, as well as the low-complexity (LC) domain, which binds the Arp2/3 complex. SNX9 also binds to PtdIns(4)P-5-kinases via its PX domain and its tubulating activity is regulated by phosphoinositides. In addition, the kinase activity of PtdIns(4)P-5-kinases is stimulated by interaction with SNX9, suggesting a positive feedback interaction between SNX9 and PtdIns(4)P-5-kinases. These results suggest that SNX9 functions in the coordination of membrane remodeling and fission via interactions with actin-regulating proteins, endocytic proteins and PtdIns(4,5)P2-metabolizing enzymes.

Small-conductance Ca2+-activated potassium channels (SKCa channels) are heteromeric complexes of pore-forming main subunits and constitutively bound calmodulin. SKCa channels in neuronal cells are activated by intracellular Ca2+ that increases during action potentials, and their ionic currents have been considered to underlie neuronal afterhyperpolarization. However, the ion selectivity of neuronal SKCa channels has not been rigorously investigated. In this study, we determined the monovalent cation selectivity of a cloned rat SKCa channel, rSK2, using heterologous expression and electrophysiological measurements. When extracellular K+ was replaced isotonically with Na+, ionic currents through rSK2 reversed at significantly more depolarized membrane potentials than the value expected for a Nernstian relationship for K+. We then determined the relative permeability of rSK2 for monovalent cations and compared them with those of the intermediate- and large-conductance Ca2+-activated K+ channels, IKCa and BKCa channels. The relative permeability of the rSK2 channel was determined as \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} \begin{equation*}{\mathrm{K}}^{+}(1.0)>{\mathrm{Rb}}^{+}(0.80)>{\mathrm{NH}}_{4}^{+}(0.19)\approx {\mathrm{Cs}}^{+}(0.19)>{\mathrm{Li}}^{+}(0.14)>{\mathrm{Na}}^{+}(0.12),\end{equation*}\end{document} indicating substantial permeability of small ions through the channel. Although a mutation near the selectivity filter mimicking other K+-selective channels influenced the size-selectivity for permeant ions, Na+ permeability of rSK2 channels was still retained. Since the reversal potential of endogenous SKCa current is determined by Na+ permeability in a physiological ionic environment, the ion selectivity of native SKCa channels should be reinvestigated and their in vivo roles may need to be restated.

Sorting nexin 9 (SNX9) is a member of the sorting nexin family of proteins, each of which contains a characteristic Phox homology domain. SNX9 is widely expressed and plays a role in clathrin-mediated endocytosis, but it is not known if it is present in neuronal cells. We report that SNX9 is expressed in the presynaptic compartment of cultured hippocampal neurons, where it binds to dynamin-1 and N-WASP. Overexpression of full-length SNX9 or a C-terminal truncated version caused severe defects in synaptic vesicle endocytosis during, as well as after, stimulation. Knockdown of SNX9 with short interfering RNA also reduced synaptic vesicle endocytosis, and the W39A mutation of SNX9 abolished the inhibitory effect of SNX9 on endocytosis. Rescue experiments showed that most of the effect of SNX9 on endocytosis results from its interaction with dynamin 1, although its interaction with N-WASP contributes in some degree. We further showed that SNX9 dimerizes through its C-terminal domain, suggesting that it may interact simultaneously with dynamin 1 and N-WASP. We propose that SNX9 interacts with dynamin-1 and N-WASP in presynaptic terminals, where it links actin dynamics and synaptic vesicle endocytosis.

This paper provides a concise review on the recent development of nanoscale hybrid systems based on carbon nanotubes (CNTs) for biological sensing and control. CNT-based hybrid systems have been intensively studied for versatile applications of biological interfaces such as sensing, cell therapy and tissue regeneration. Recent advances in nanobiotechnology not only enable the fabrication of highly sensitive biosensors at nanoscale but also allow the applications in the controls of cell growth and differentiation. This review describes the fabrication methods of such CNT-based hybrid systems and their applications in biosensing and cell controls.

We report a colorimetric dye-functionalized sol-gel matrix on carbon nanotubes for use as a refreshable and flexible gas sensor with humidity calibration. Here, we fabricated gas sensors by functionalizing dye molecules on the top of carbon nanotube networks via a sol-gel method. Using hybrid gas sensors with different dye molecules, we could selectively detect various hazardous gases, such as NH3, Cl2 and SO2 gases, via optical and electrical signals. The sensors exhibited rather large conductance changes of more than 50% following exposure to gas species with concentrations even under the permissible exposure limit. Significantly, we could refresh used gas sensors by simply exposing them to fresh N2 gas without any heat treatment. Additionally, our sensors can be bent to form versatile practical sensor devices, such as tube-shape sensors for ventilation tubes. This work shows a simple but powerful method for building refreshable and selective gas sensors for versatile industrial and academic applications.

International audience; Semiconducting single-walled carbon nanotube-Au (sSWCNT-Au) hybrid films are prepared to build a thermistor device with an adjustable temperature coefficient and show that the embedded sSWCNTs reduce the resistivity and noise source activities in the nanoscale regions of the film. The temperature coefficient of the hybrid films can be adjusted from negative to positive values simply by increasing the deposited Au thickness. Moreover, scanning noise microscopy is utilized to map the nanoscale variation of the resistivity and noise source density on the sSWCNT-Au hybrid films. Interestingly, the map shows that the regions with both sSWCNT and Au exhibit three times lower resistivity and 18 times smaller noise source activities than pristine Au regions, indicating that sSWCNTs embedded in metallic films can significantly reduce the resistivity and electrical noise source activities in the film.