The Temporal Mechanisms Guiding Interneuron Differentiation in the Spinal Cord

Neurogenesis timing is an essential developmental mechanism for neuronal diversity and organization throughout the central nervous system. In the mouse spinal cord, growing evidence is beginning to reveal that neurogenesis timing acts in tandem with spatial molecular controls to diversify molecularly and functionally distinct post-mitotic interneuron subpopulations. Particularly, in some cases, this temporal ordering of interneuron differentiation has been shown to instruct specific sensorimotor circuit wirings. In zebrafish, in vivo preparations have revealed that sequential neurogenesis waves of interneurons and motor neurons form speed-dependent locomotor circuits throughout the spinal cord and brainstem. In the present review, we discuss temporal principals of interneuron diversity taken from both mouse and zebrafish systems highlighting how each can lend illuminating insights to the other. Moving forward, it is important to combine the collective knowledge from different systems to eventually understand how temporally regulated subpopulation function differentially across speed- and/or state-dependent sensorimotor movement tasks.     

Does a helping hand mean a heavy heart? Helping behavior and well-being among spouse caregivers.

Being a caregiver for an ill or disabled loved one is widely recognized as a threat to the caregiver’s quality of life. Nonetheless, research indicates that helping behavior, broadly construed, promotes well-being. Could helping behavior in a caregiving context promote well-being as well? In the present study, we used ecological momentary assessment to measure active helping behavior and both positive and negative affect in 73 spouse caregivers. Results indicate that when controlling for care recipient illness status and functional impairment and caregiver “on call” caregiving time, active helping predicted greater caregiver positive affect—especially for individuals who perceived themselves as interdependent with their spouse. In addition, although both helping and on-call time predicted greater negative affect for caregivers who perceived low interdependence, helping was unrelated to negative affect among caregivers perceiving high interdependence. Helping valued loved ones may promote caregivers’ well-being. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Single‐Step Carbothermal Synthesis of High‐Purity MAX Phase Powders

The M_n+1AX_n phases Cr₂GeC and Cr₂GaC were synthesized with high phase‐purity directly from Cr₂O_3; Ge or Ga; and C using a single‐step carbothermal reduction. X‐ray diffraction and scanning electron microscope analysis of the materials shows them to be >99 mol% Cr₂GeC and 92 mol% Cr₂GaC, respectively. Extension to non‐Cr systems is briefly demonstrated by applying the method to the synthesis of V₂GeC.     

A Dynamic Comparative Analysis of International Innovation Networks in Emerging Market MNCs

This paper compares the international innovation strategies of emerging market MNCs (EMNCs) with those of developed country MNCs (DMNCs). More specifically, we analyze the patent outcomes related to the use of international innovation networks (IINs) of EMNCs in developed markets compared with those of DMNCs in emerging markets. We explore the convergence and volatility patterns in patent generation within these IINs, considering the use of overseas R&D affiliates and the outcomes of interactions between foreign R&D affiliates and home headquarters for generating patents over a 20-year period. Our findings are broadly supportive of the idea that the trends in the volume and volatility of patents generated from the underlying IINs used by EMNCs are converging with those of DMNCs. This is in line with the predictions of a number of current international business theories regarding EMNC international expansion.     

Does auditory streaming require attention? Evidence from attentional selectivity in short-term memory.

R. P. Carlyon, R. Cusack, J. M. Foxton, and I. H. Robertson (2001; see record 2001-16068-008) have argued that attention is crucial for auditory streaming. The authors review R. P. Carlyon et al.'s (2001) arguments and suggest that a pertinent literature, the irrelevant sound paradigm--demonstrating preattentive auditory streaming--has been overlooked. In illustration of this alternative approach, the authors include a novel single experiment demonstrating the impact of preattentive auditory streaming on short-term serial memory. It is concluded that R. P. Carlyon et al.'s (2001) results do not definitively demonstrate that auditory streaming processes are dependent on attention; indeed, they are compatible with alternative accounts of the relationship between perceptual organization and attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Functional characteristics of the inner voice and the inner ear: Single or double agency?

Double agency theories of short-term memory posit the functional independence of a phonological store (inner ear) and articulatory process (inner voice). A series of 5 experiments challenges this view. Articulatory suppression during retention of 9-item lists gives rise to a changing-state effect similar to that shown for irrelevant speech. Also, vocalized suppression is more disruptive than silently mouthed suppression, but this difference arises from vocalization itself rather than from any auditory feedback to which it gives rise. Class similarity between the to-be-remembered items and the articulatory material is not a critical determinant, but the effect occurs only with tests of serial order. For mouthed suppression, the irrelevant speech effect is only attenuated with changing-state suppression. Also, the presence of changing-state irrelevant speech abolishes the changing-state effect of articulatory suppression. Functional equivalence of codes from auditory, visual, and articulatory sources is claimed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Graphene Oxide Based Transparent Resins For Accurate 3D Printing of Conductive Materials

Digital Light Processing (DLP) allows the fast realization of 3D objects with high spatial resolution. However, DLP is limited to transparent resins, and therefore not well suited for printing electrically conductive materials. Manufacturing conductive materials will significantly broaden the spectrum of applications of the DLP technology. But conductive metals or carbon-based fillers absorb and scatter light; inhibiting thereby photopolymerization, and lowering resolution. In this study, UV transparent liquid crystal graphene oxide (GO) is used as precursor for generating in situ conductive particles. The GO materials are added to a photopolymerizable resin via an original solvent exchange process. By contrast to earlier contributions, the absence of drying during the all process allows the GO material to be transferred as monolayers to limit UV scattering. The absence of UV scattering and absorption allows for fast and high-resolution 3D printing. The chosen resin sustain high temperature to enable an in situ efficient thermal reduction of GO into reduced graphene oxide (rGO) that is electrically conductive. The rGO particles form percolated networks with conductivities up to 1.2 × 10⁻² S m⁻¹. The present method appears therefore as a way to reconcile the DLP technology with the manufacturing of 3D electrically conductive objects.     

Zinc sorption by a bacterial biofilm

Microbial biofilms are present in soils, sediments, and natural waters. They contain bioorganic metal-complexing functional groups and are thought to play an important role in metal cycling in natural and contaminated environments. In this study, the metal-complexing functional groups present within a suspension of bacterial cell aggregates embedded in extracellular polymeric substances (EPS) were identified in Zn adsorption experiments conducted at pH 6.9 with the freshwater and soil bacterium Pseudomonas putida. The adsorption data were fit with the van Bemmelen-Freundlich model. The molecular speciation of Zn within the biofilm was examined with Zn K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy. The Zn EXAFS data were analyzed by shell-by-shell fitting and linear least-squares fitting with reference spectra. Zinc sorption to the biofilm was attributed to predominantly Zn--phosphoryl (85 +/- 10 mol %) complexes, with a smaller contribution to sorption from carboxyl-type complexes (23 +/- 10 mol %). The results of this study spectroscopically confirm the importance of phosphoryl functional groups in Zn sorption by a bacterial biofilm at neutral pH.     

A planar subharmonically-pumped 71 GHz receiver with integral feed antenna

A planar, subharmonically-pumped, hybrid millimeter-wave receiver with integral antenna is described. Coplanar waveguide filters are used to isolate the ports and provide image enhancement. The integral planar antenna has 12 dB gain and is suited for use as a feed. The main lobe is normal to the substrate surface. The receiver is designed for an instantaneous bandwidth of 10 GHz. Experiments at 71 GHz indicate single-sideband mixer conversion loss of 6.5 dB. We believe that this represents the highest level of integration yet demonstrated in this frequency range.