Developmental regulation of neuronal K+ channels by target-derived TGF beta in vivo and in vitro

The functional expression of Ca2+-activated K+ channels (KCa) in developing chick ciliary ganglion (CG) neurons requires interactions with target tissues and preganglionic innervation. Here, we show that the stimulatory effects of target tissues are mediated by an isoform of TGFbeta. Exposure of cultured CG neurons to TGFbeta1, but not TGFbeta2 or TGFbeta3, caused robust stimulation of KCa. The KCa stimulatory effects of target tissue extracts were blocked by a neutralizing pan-TGFbeta antiserum but not by specific TGFbeta2 or TGFbeta3 antisera. Intraocular injection of TGFbeta1 caused robust stimulation of KCa, whereas intraocular injection of pan-TGFbeta antiserum inhibited expression of KCa in CG neurons developing in vivo. The effects of TGFbeta1 were potentiated by beta-neuregulin-1, a differentiation factor expressed in preganglionic neurons.     

When do opposites attract? Interpersonal complementarity versus similarity.

Two experiments examined whether interpersonal complementarity or similarity influences people's satisfaction with dyadic interactions. Participants in complementary partnerships (submissive people with dominant partners, dominant people with submissive partners) reported more satisfaction than did those with similar partners. In Study 1 complementarity referred to the match between the participants' self-reported interpersonal style (dominant or submissive) and the role enacted by a confederate (dominant or submissive). In Study 2 participants interacted in pairs, and complementarity referred to the match between one participant's interpersonal goals and the other's overt behavior. Participants whose goals were complemented by their partners' behavior were more satisfied with the interaction than those whose goals were not. In both studies satisfied participants perceived their partners as similar to themselves. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Mitochondrial metabolism of (D,L)-threo-9, 10-dibromo palmitic acid

Bromination of palmitoleic or palmitelaidic acid proceeds bytrans addition and yields dibrominated products which cannot undergo β-oxidation when incubated with mitochondria isolated from hamster brown adipose tissue. These mitochondria were selected because they have a high capacity for oxidation of C₁₆ fatty acids and because they are readily uncoupled by an excess of free fatty acids of this chain length. The only metabolites which could be recovered from the incubation mixtures were dibromopalmitoylcarnitine and dibromopalmitoyl CoA. Free fatty acid was also recovered. Addition of synthetic carnitine or CoA esters of brominated fatty acids did not interfere with subsequent oxidation of palmitoylcarnitine. Addition of the free brominated fatty acids did significantly increase the rate of oxidation of subsequent additions of palmitoylcarnitine, as did other known synthetic uncouplers. These results are consistent with observations by others that feeding brominated oils leads to brominated fatty acid incorporation into tissue lipids, and indicate why this is so. They also provide a possible explanation for the hepatic damage noted in feeding experiments.     

Statewide assessment of school-age children with asthma in Delaware

In Delaware, asthma affects almost 14,000 children. The American Lung Association of Delaware and the University of Delaware surveyed school nurses to identify the needs of children with asthma and the services and accommodations available for these children. Researchers developed a survey instrument that was mailed to all Delaware schools (N = 324). The response rate was 38.6% (n = 125). According to respondents, a variety of protocols were in place regarding the administration of asthma medications. Respondents also reported that several measures had been taken to modify the school environment to improve air quality and reduce asthma triggers. Most respondents (77%) indicated they did not have asthma education programs in their schools. Findings from this study sparked development of a multidisciplinary Delaware Asthma Committee, an Asthma Education Center, and a statewide system for communicating with the parents of children with asthma.     

Synaptology of the olfactory bulb of an elasmobranch fish, Sphyrna tiburo

The ultrastructure of the elasmobranch olfactory bulb was examined in order to determine the synaptology of the olfactory circuitry in the bonnethead shark, Sphyrna tiburo. The compartmentalization of the bulb, together with the lack of mitral cell basal dendrites, suggests a different way of performing lateral communication between mitral cells of the olfactory bulb. The results show that granule cells assume an important role by directly interlinking mitral cells. A corollary of this is the segregation of the input onto the mitral cell dendritic arborization: afferent fibers synapse onto the intraglomerular mitral terminals, whereas most local circuit interactions utilize extraglomerular synapses located on the shafts and the somas of the mitral dendrites. Therefore, the elasmobranch synaptic pattern is different from that of higher vertebrates; This might represent the use of a different neural route to achieve the same processing task.     

Neuregulins stimulate the functional expression of Ca2+-activated K+ channels in developing chicken parasympathetic neurons

The developmental expression of macroscopic Ca2+-activated K+ currents (IK[Ca]) in chicken ciliary ganglion (CG) neurons is dependent in part on trophic factors released from preganglionic nerve terminals. Neuregulins are expressed in the preganglionic neurons that innervate the chicken CG and are therefore plausible candidates for this activity. Application of 1 nM beta1-neuregulin peptide for 12 hr evokes a large (7- to 10-fold) increase in IK[Ca] in embryonic day 9 CG neurons, even in the presence of a translational inhibitor. A similar posttranslational effect is produced by high concentrations (10 nM) of epidermal growth factor and type alpha transforming growth factor but not by 10 nM alpha2-neuregulin peptide or by neurotrophins at 40 ng.ml-1. beta1-neuregulin treatment for 12 hr also confers Ca2+ sensitivity onto large-conductance (285 pS) K+ channels observed in inside-out patches. beta-Neuregulins have no effect on voltage-activated Ca2+ currents of CG neurons. These data support the hypothesis that beta-neuregulins mediate the trophic effects of preganglionic nerve terminals on the electrophysiological differentiation of developing CG neurons.     

Comparison of scale‐up methods for dispersive mixing in twin‐screw extruders

Twin‐screw extrusion processes are commonly refined on laboratory‐scale extruders then scaled‐up to manufacturing systems. When using twin‐screw extrusion to compound filler into a polymer, the dispersion of the filler must be considered during scale‐up. In this work, two scale‐up methods are evaluated for how accurately they scale dispersion as measured by the Residence Stress Distribution, an experimental method that quantifies stress developed in a twin‐screw extruder. The first scale‐up method evaluated is the industry‐standard scaling based on maintaining equivalent volumetric flow rate across extruder sizes. Volumetric scaling is compared to a second, novel scale‐up method, the percent drag flow rule, which maintains the same degree of fill in the strongest dispersive screw elements on all extruder sizes. Both scale‐up rules have been used to scale between three extruder sizes and have been evaluated for how accurately the larger extruders recreate the dispersive mixing of the smallest machine. Results indicate that the percent drag flow scale‐up more accurately maintains dispersive mixing behavior than the volumetric scaling. Furthermore, percent drag flow scale‐up resulted in all three extruder sizes behaving similarly to changes in operating conditions. These results indicate that percent drag flow scale‐up is a valid technique to scale real industrial processes. POLYM. ENG. SCI., 57:345–354, 2017. © 2016 Society of Plastics Engineers     

An experimental and kinetic modeling study of methyl formate low-pressure flames

The oxidation of methyl formate (CH₃OCHO), the simplest methyl ester, is studied in a series of burner-stabilized laminar flames at pressures of 22–30 Torr and equivalence ratios (Φ) from 1.0 to 1.8 for flame conditions of 25–35% fuel. Flame structures are determined by quantitative measurements of species mole fractions with flame-sampling molecular-beam synchrotron photoionization mass spectrometry (PIMS). Methyl formate is observed to be converted to methanol, formaldehyde and methane as major intermediate species of mechanistic relevance. Smaller amounts of ethylene and acetylene are also formed from methyl formate oxidation. Reactant, product and major intermediate species profiles are in good agreement with the computations of a recently developed kinetic model for methyl formate oxidation [S. Dooley, M.P. Burke, M. Chaos, Y. Stein, F.L. Dryer, V.P. Zhukov, O. Finch, J.M. Simmie, H.J. Curran, Int. J. Chem. Kinet. 42 (2010) 527–529] which shows that hydrogen abstraction reactions dominate fuel consumption under the tested flame conditions. Radical–radical reactions are shown to be significant in the formation of a number of small concentration intermediates, including the production of ethyl formate (C₂H₅OCHO), the subsequent decomposition of which is the major source of observed ethylene concentrations. The good agreement of model computations with this set of experimental data provides a further test of the predictive capabilities of the proposed mechanism of methyl formate oxidation. Other salient issues in the development of this model are discussed, including recent controversy regarding the methyl formate decomposition mechanism, and uncertainties in the experimental measurement and modeling of low-pressure flame-sampling experiments. Kinetic model computations show that worst-case disturbances to the measured temperature field, which may be caused by the insertion of the sampling cone into the flame, do not alter mechanistic conclusions provided by the kinetic model. However, such perturbations are shown to be responsible for disparities in species location between measurement and computation.