Effect of EphA4 signaling mutations on auditory function

Neural pathways underlie the ability of the auditory system to perceive sound. Organization of neural pathways into functional auditory circuitry is accomplished in part by Eph and ephrin signaling proteins. One of these signaling proteins, the EphA4 receptor tyrosine kinase protein, acts as an axon-guidance molecule to aid in target selection and to maintain tonotopicity in the auditory brainstem and midbrain. Genetic mutations of the EphA4 protein have been shown to affect structural auditory development, but there is limited research which shows the functional effects of these mutations. The goal of the present study was to determine the functional effects of EphA4 lacZ mutations on auditory processing using physiologic measures. Auditory Brainstem Response (ABR) measures including summating potential (SP) amplitude were recorded in EphA4 lacZ mutant mice (with C57BL/6J background strain) prior to three months of age and compared to a control group of wild-type littermates. ABR wave latency and threshold analysis in heterozygous mice showed no significant differences from controls. Comparison of homozygous mutant mice to wild-type controls showed significantly elevated (poorer) ABR thresholds in the homozygous group for 8 kHz tone-burst, 12 kHz tone-burst, and click stimuli. SP amplitudes were increased in the homozygous group suggesting mutation related changes to the auditory system. Deficits in auditory function seen in the homozygous mutant strain provide evidence that normal EphA4 expression is necessary for normal auditory function. Preserved function in the heterozygous mutants suggests that one allele is sufficient for normal function at approximately one to three months of age. Our findings support the role of EphA4 in the development of the auditory function

NASTRAN analysis of an air storage piping system

The application of NASTRAN to a complex piping design evaluation problem is summarized. Emphasis is placed on structural modeling aspects, problems encountered in modeling and analyzing curved pipe sections, principal results, and relative merits of using NASTRAN as a pipe analysis and design tool. In addition, the piping and manifolding system was analyzed with SNAP (Structural Network Analysis Program). The parallel SNAP study provides a basis for limited comparisons between NASTRAN and SNAP as to solution agreement and computer execution time and costs

Nine percent nickel steel heavy forging weld repair study

The feasibility of making weld repairs on heavy section 9% nickel steel forgings such as those being manufactured for the National Transonic Facility fan disk and fan drive shaft components was evaluated. Results indicate that 9% nickel steel in heavy forgings has very good weldability characteristics for the particular weld rod and weld procedures used. A comparison of data for known similar work is included

RF Heating of Laser-Induced Graphite (LIG) on Polymer Surfaces

In this report, we investigate laser-induced graphite (LIG) structures formed in polymeric substrates in order to quantify LIG heating response to radio frequency (RF) fields. Graphitic structures were produced from various polymeric substrates via laser irradiation of the polymer surface. We find that RF responsive, graphitic structures may be produced from polyimide (PI), polyether imide (PEI), polyether sulfone (PESU), polyether ether ketone (PEEK), and polycarbonate (PC) using a conventional laser cutting machine. The graphitic structures are also conductive in addition to being RF responsive. Exposure of LIG to RF fields resulted in the rapid heating of LIG with heating rates up to 126 °C/s. This heating response may be used in advanced manufacturing as a means to rapidly weld polymer-polymer interfaces, as will be demonstrated in this report. This technique uses RF fields to induce localized heating in contrast to uniform heating from external sources such as ovens or furnaces. Finally, we aim to determine how LIGpolymer composites may function in an industrial setting, with particular application to additive manufacturing and functional coatings. One novel application of these findings is the potential use of LIG-polymer heating elements on thermoplastic filaments for welding 3D-printed filament traces together and improving the isotropic strength of 3Dprinted structures. First, we review the necessary background information on LIG formation, thermoplastic joining, and nanomaterial heating in response to electromagnetic fields. We then describe the laser etching procedure used to produce graphitic structures from neat polymer substrates. The method and experimental setup required to generate RF fields and subsequent RF field heating are also addressed. The proposed work would enable entirely new techniques for polymer processing, where the RF responsive filler is generated in situ

Bone Density Variation in Rattails (Macrouridae,Gadiformes): Buoyancy, Depth, Body Size, and Feeding

A grant from the One-University Open Access Fund at the University of Kansas was used to defray the author's publication fees in this Open Access journal. The Open Access Fund, administered by librarians from the KU, KU Law, and KUMC libraries, is made possible by contributions from the offices of KU Provost, KU Vice Chancellor for Research & Graduate Studies, and KUMC Vice Chancellor for Research. For more information about the Open Access Fund, please see http://library.kumc.edu/authors-fund.xml.Extreme abiotic factors in deep-sea environments, such as near-freezing temperatures, low light, and high hydrostatic pressure, drive the evolution of adaptations that allow organisms to survive under these conditions. Pelagic and benthopelagic fishes that have invaded the deep sea face physiological challenges from increased compression of gasses at depth, which limits the use of gas cavities as a buoyancy aid. One adaptation observed in deep-sea fishes to increase buoyancy is a decrease of high-density tissues. In this study, we analyze mineralization of high-density skeletal tissue in rattails (family Macrouridae), a group of widespread benthopelagic fishes that occur from surface waters to greater than 7000 m depth. We test the hypothesis that rattail species decrease bone density with increasing habitat depth as an adaptation to maintaining buoyancy while living under high hydrostatic pressures. We performed micro-computed tomography (micro-CT) scans on 15 species and 20 specimens of rattails and included two standards of known hydroxyapatite concentration (phantoms) to approximate voxel brightness to bone density. Bone density was compared across four bones (eleventh vertebra, lower jaw, pelvic girdle, and first dorsal-fin pterygiophore). On average, the lower jaw was significantly denser than the other bones. We found no correlation between bone density and depth or between bone density and phylogenetic relationships. Instead, we observed that bone density increases with increasing specimen length within and between species. This study adds to the growing body of work that suggests bone density can increase with growth in fishes, and that bone density does not vary in a straightforward way with depth

Marine fish may be biochemically constrained from inhabiting the deepest ocean depths

No fish have been found in the deepest 25% of the ocean (8,400-11,000 m). This apparent absence has been attributed to hydrostatic pressure, although direct evidence is wanting because of the lack of deepest-living species to study. The common osmolyte trimethylamine N-oxide (TMAO) stabilizes proteins against pressure and increases with depth, going from 40 to 261 mmol/kg in teleost fishes from 0 to 4,850 m. TMAO accumulation with depth results in increasing internal osmolality (typically 350 mOsmol/kg in shallow species compared with seawater\u27s 1,100 mOsmol/kg). Preliminary extrapolation of osmolalities of predicted isosmotic state at 8,000-8,500 m may indicate a possible physiological limit, as greater depths would require reversal of osmotic gradients and, thus, osmoregulatory systems. We tested this prediction by capturing five of the second-deepest known fish, the hadal snailfish (Notoliparis kermadecensis; Liparidae), from 7,000 m in the Kermadec Trench. We found theirmuscles to have a TMAOcontent of 386 ± 18 mmol/kg and osmolality of 991 ± 22 mOsmol/kg. These data fit previous extrapolations and, combined with new osmolalities from bathyal and abyssal fishes, predict isosmotic state at 8,200 m. This is previously unidentified evidence that biochemistry could constrain the depth of a large, complex taxonomic group

The human side of teaching : an inquiry into the limits and possibilities of teacher evaluation

The focus of this study was the human side of teaching, i.e., those traits and characteristics of teaching which are not formally evaluated, but must be present for effective teaching-learning to take place. There were 18 traits and characteristics identified. A qualitative approach to research was used and included three methods of field research to obtain data on teachers and teaching. The methods were: (1) the observer-as-participant; (2) interviews as conversations; and (3) a critical incident technique survey. Based on the findings of this study, there is a human side of teaching. The 18 characteristics and traits were found in all aspects of the study. Teacher evaluation has become more positivist in nature, and the emphasis on the technical causes the human side of teaching to be missed. There must be a reconceptualization of teachers and teaching to incorporate a qualitative approach so that teachers can be understood in their world

Nitrosamines in pilot-scale and full-scale wastewater treatment plants with ozonation

Ozone-based treatment trains offer a sustainable option for potable reuse applications, but nitrosamine formation during ozonation poses a challenge for municipalities seeking to avoid reverse osmosis and high-dose ultraviolet (UV) irradiation. Six nitrosamines were monitored in full-scale and pilot-scale wastewater treatment trains. The primary focus was on eight treatment trains employing ozonation of secondary or tertiary wastewater effluents, but two treatment trains with chlorination or UV disinfection of tertiary wastewater effluent and another with full advanced treatment (i.e., reverse osmosis and advanced oxidation) were also included for comparison. N-nitrosodimethylamine (NDMA) and N-nitrosomorpholine (NMOR) were the most prevalent nitrosamines in untreated (up to 89ng/L and 67ng/L, respectively) and treated wastewater. N-nitrosomethylethylamine (NMEA) and N-nitrosodiethylamine (NDEA) were detected at one facility each, while N-nitrosodipropylamine (NDPrA) and N-nitrosodibutylamine (NDBA) were less than their method reporting limits (MRLs) in all samples. Ozone-induced NDMA formation ranging fro

Fishes of the hadal zone including new species, in situ observations and depth records of Liparidae

AbstractObservations and records for fish exceeding 6000m deep are few and often spurious. Recent developments in accessing and sampling the hadal zone 6000–11,000m) have led to an acceleration in new findings in the deep subduction trenches, particularly in the Pacific Ocean. This study describes the discovery of two new species of snailfish (Liparidae) from the Mariana Trench; the ‘Mariana snailfish’ (6198–8076m) and the ‘Ethereal snailfish’ (7939–8145m). These new findings represent respectively the deepest known specimen caught with corroborating depth data, and the deepest fish seen alive. Further specimens and observations of the Kermadec Trench snailfish, Notoliparis kermadecensis, are also presented, as well as the first hadal records of Synaphobranchidae and Zoarcidae (6068 and 6145m respectively) and a depth extension for the Macrouridae (maximum depth now 7012m). Details of these new snailfish specimens caught by baited trap and behaviour observations filmed by baited cameras are presented. An updated assessment of fishes from hadal depths is also reported

Trophic interactions of megafauna in the Mariana and Kermadec trenches inferred from stable isotope analysis

Hadal trenches house distinct ecosystems but we know little about their sources of nutrition or trophic structures. We evaluated megafaunal food web structure and nutritional sources in the Kermadec and Mariana trenches using carbon and nitrogen stable isotope analysis (δ15N and δ13C values) of bulk tissues and proteinaceous individual amino acids (AAs). In the Kermadec Trench, bulk δ15N values ranged from 5.8‰ in trench sediment to 17.5‰ in tissues of the supergiant amphipod, Allicela gigantea. δ15N values of detritivores were much higher than those of sediments (by 7.5‰ more). The δ13C values ranged from −21.4‰ in sediments to −17.3‰ in the brittle star, Ophiolimna sp., and did not co-vary with δ15N values. In the Mariana Trench, only bait-attending fauna and surface sediments were available for analysis. Mariana Trench fishes, amphipods, and sediments had slightly lower δ15N values than those from the Kermadec Trench, possibly because the Mariana Trench lies under more oligotrophic surface waters. We found evidence for multiple food inputs to the system in each trench, namely substantially higher δ15N values in detritivores relative to sediment and high variability in δ13C values. Trophic levels determined from isotopic analysis of individual AAs in the Kermadec Trench ranged from three for detritivores to five for fishes. Source AA δ15N values were variable (range of ~7.0‰ in average δ15N source AA values), with much of this variation occurring in small amphipods. For the other fauna sampled, there was a significant increase in δ15N source AA values with increasing collection depth. This increase could reflect larger amounts of highly microbially reworked organic matter with increasing depth or sporadic input from turbidity flows. Although further sampling across a broader faunal diversity will be required to understand these food webs, our results provide new insights into hadal trophic interactions and suggest that trench food webs are very dynamic