bluuebunny/crossref_metadata_2025 huggingface dataset:
A French romance in Wales: Ystorya Bown o Hamtwn: processes of medieval translations. Part I.
Authors: Poppe Erich , Reck Regine
Published: February 2016

1. Medieval Welsh Translations and Translators; 2. The Story of Boeve de Haumtone; 3. The Plot of
Merlin's last cry: ritual burial and rebirth of the poet in Celtic and Norse tradition
Authors: Eson Lawrence E.
Published: February 2016

In early Celtic literature, a clear pattern may be identified in which the Celtic archetypal poet-prophet becomes inspired through interment in a tomb or some other dark, enclosed space. In this scenario, the novice poet-prophet undergoes an initiation into the secrets of his craft by means of a ritual death and rebirth that he experiences within a chthonic setting. The picture that emerges of the archetypal poet-prophet of Celtic, as well as other Indo-European literatures, is one of a mantically inspired figure who gains his phenomenal abilities directly from potent otherworldly forces, which are often, but not always, associated with spirits of the dead. Recent scholarship has established the validity of this pattern in the cases of the archetypal Welsh poets Taliesin and Aneirin, but it may also be demonstrated in the medieval Welsh and somewhat later Arthurian material concerned with Merlin (called
‘Bodily matters’ in early Irish narrative literature
Authors: Edel Doris
Published: February 2016

Not surprisingly, the members of the Celtic Revival had difficulties reconciling the directness of the older Irish literature in bodily matters with the literary and moral code of their own time. In this they were no exception, although in their case the problem was aggravated by Ireland's colonial status. Everywhere in that world that we have somewhat incorrectly labelled as Victorian – a world shaped by nationalism, puritanism and triumphalist churches of various denominations –, the newly discovered medieval literatures confronted scholar and educated reader alike with this problem. As an example from outside Ireland may serve the great medievalist Joseph Bédier. In his monumental study of the French
Keltische Äquivalente klassischer Epitheta und andere sprachliche und nicht-sprachliche Phänomene im Rahmen der sogenannten ‚interpretatio Romana‘
Authors: Stempel Patrizia de Bernardo
Published: February 2016

Besides listing several cases in which Latin divine names seem to stand for indigenous ones, i.e. to translate them, this article offers a comprehensive view of the various types of theonymic strings in which the name of a classical deity is, more or less explicitly, involved. It shows that those in which a classical deity is assimilated to an indigenous one actually constitute only a minor group while the majority just use Celtic words for describing the classical deity involved. There is also evidence of similar renderings by means of Germanic words. The article inquires into the social and historical constraints which prompted the three phenomena and proposes a very general relative chronology.
De-adjectival preverbs in the Old Irish verbal complex: a synchronic and diachronic study
Authors: Castillero Carlos García
Published: February 2016

Die altirischen deadjektivischen Präverbien, d. h. relativ selten gebrauchte Präverbien, die ein etymologisches Pendant in altirischen Adjektiven haben, nehmen im altirischen Verbalkomplex einen mittleren Platz ein zwischen konjunkten Partikeln und lexikalischen Präverbien. Semantisch lassen sie sich in zwei Gruppen, Evaluation und relative Zeit, einteilen. Diachron werden die altirischen deadjektivischen Präverbien als Rückbildungen von nominalen Komposita (z. B. nach míimbert ‚Enttäuschung‘, mí-t·n-imret ‚dass sie ihn enttäuschen‘) und von Spaltsätzen mit fokussiertem Adjektiv (z. B. nach cid moch do-nd∙té ‚selbst wenn er früh dahin kommt‘, mos·r-iccub-sa ‚ich werde bald ankommen‘), und auch aus typisch ‘floating’ Adjektiven (vgl. den redundanten Ausdruck is hé céetne fer cetaru∙ chreti ‚er is der erste Mann, der zuerst geglaubt hat‘) erklärt.
The Breton migration: a new synthesis
Authors: Guy Ben
Published: February 2016

L’article examine à nouveau la question comment et pourquoi une proportion significative de la population du nord-ouest de la Gaule en est arrivée à parler une langue bretonne (britannique) et à s’identifier à la culture bretonne (britannique) au cours de la transition de l’Antiquité tardive au Haut Moyen-Âge. Il étudie les processus auxquels les sources écrites font allusion en utilisant des arguments sociolinguistiques et archéologiques. On propose l’explication suivante : Depuis la première moitié du cinquième siècle, les Bretons sont partis de la péninsule sudouest de la Grande Bretagne, particulièrement du comté actuel de Dorset, pour aller s’installer au nord-ouest de la Gaule. Cette migration est causée à la fois par l’effondrement de l’économie de la Bretagne romaine, par la militarisation de l’élite des propriétaire fonciers locaux, et par la menace des envahisseurs anglo-saxons.
Synthesis and single-crystal structure of the pseudo-ternary compounds LiA[N(CN)2]2 (A = K or Rb)
Authors: Reckeweg Olaf , DiSalvo Francis J.
Published: February 2016

Crystals of LiA[N(CN)2]2 were obtained from the reaction of LiCl and ACl (A = K or Rb) with Ag[N(CN)2] in water and subsequent evaporation of the filtered solution at 80 °C under normal atmospheric conditions. Crystals of the title compound form thin rectangular plates that are transparent, colorless, and very fragile. Single-crystal structure analyses have shown that both compounds are isotypic and adopt the tetragonal space group I4/mcm (no. 140, Z = 4) with the cell parameters a = 701.53(12) and c = 1413.7(5) pm for LiK[N(CN)2]2 and a = 730.34(10) and c = 1414.4(4) pm for LiRb[N(CN)2]2. The crystal structure is described and compared to that of the pseudo-binary alkali metal dicyanamides.
Development and Implementation of a High-Pressure, Double-Acting, Bi-Directional Loading Cell for Drilled Shafts
Authors: Choi Yongkyu , Lee Min-Hee , Nam Moon S. , Kim Tae-Hyung , Stuedlein Armin W.
Published: February 2016

Drilled shaft foundation elements provide a cost-effective foundation alternative for the support of building and bridge superstructure loads. Bi-directional pile loading tests (BDPLTs) to evaluate the capacity of drilled shafts have become popular owing to their capacity to save time and effort as compared to the use of top-down loading tests. However, the use of BDPLTs requires that production shafts be post-grouted following testing in order to assure appropriate in-service performance. Commonly used single-acting loading cells and/or loading cell construction details can pose the potential for the development of voids following post-grouting due to their monotonic jacking action and large footprint. This paper described the development and use of high pressure bi-directional loading cells intended to minimize the possibility of post-test construction defects. First, a comparison was made between the single-acting and double-acting loading cells. Second, the results of laboratory calibrations on the pressurized loading cells were performed, as were component testing of the pumps, hoses, and hydraulic fluid synchronization lines. Then, the use of the new high pressure double-acting loading cells in production testing of instrumented shafts was described, and the efficacy of the new loading cells was illustrated. The new loading cells provided the profession with a load cell alternative for conducting BDLTs and should serve to help reduce the risk of post-test grouting defects in drilled shaft foundations.
Deflection Measurement of Bored Pile Body With Steel Bar Meters in the Lateral Load Test
Authors: Chen Xiang , Xu Zhaoyi
Published: February 2016

This paper presents a lateral load test conducted with a service bored grout pile. In this test, 15 pairs of steel bar meters were mounted in the pile body. The equipment not only measures the section moments of the pile body, but also measures the deflections and rotations of the pile body, which are measured by inclinometers traditionally. A comparison between the deformation near the pile head measured by the steel bar meters, and the one measured by four dial gauges proved that it is valid to use steel bar meters to measure the lateral deformation of pile body during lateral loading tests. Moreover, the results are very precise before the lateral load exceeds the elastic limit, which was determined as 120 kN in the present study.
Measurement of Average Tensile Force for Individual Steel Fiber Using New Direct Tension Test
Authors: Pinkerton Luke R. , Hoz Samhar , Novak Jeff
Published: February 2016

The use of steel-fiber reinforcement as an alternative to conventional reinforcement of various concrete structures has been limited in the construction industry. This is because of the fact that, unlike traditional reinforcement, the performance characterization of steel-fiber concrete is not standardized, because the fibers are distributed throughout the concrete section. Whereas direct tensile resistance is the performance measurement required for design, the steel-fiber industry has yet to actively employ direct tensile testing of steel fibers. The tensile response of steel-fiber-reinforced concrete has been investigated. The primary purpose of this paper is to present a robust new direct tension test method. This method is able to determine the uniaxial tensile response of steel-fiber-reinforced concrete. The method uses a three-dimensional “hourglass”-shaped tapered specimen. This paper also focuses on developing a practical method to determine the average tensile force per fiber.
Exploring Relationships in Surface-Hardness Data Collected With Different Instruments
Authors: Thoms A. W. , Brosnan J. T. , Sorochan J. C. , Saxton A. M.
Published: February 2016

Two instruments are used to measure impact attenuation on athletic field playing surfaces: the F355 Apparatus A (F355) and the Clegg Impact Soil Tester (CIST). Although both devices use weighted missiles equipped with accelerometers to measure impact attenuation, Gmax, little information is available in the peer-reviewed scientific literature comparing data collected with these devices on natural and synthetic turf athletic field playing surfaces. A 2-year field study was conducted at the University of Tennessee Center for Athletic Field Safety in 2012 and 2013 to determine whether data collected with a CIST could be used to predict values with the F355. Ten different synthetic turf and four natural turfgrass surfaces constructed over four root zone types were subjected to 30 simulated traffic events at two rates (three events wk−1 and 10 events wk−1). Three impact attenuation samples were collected with both devices on all surfaces for each rate of simulated traffic. Two regression analyses were conducted: one using all 252 data points collected annually and a second that incorporated blocking to account for within surface sampling. In both years, associations between impact attenuation data collected with the CIST and the F355 were weak. CIST values only explained 9 % of the variability in F355 data in 2012 (R2 = 0.09) and 24 % in 2013 (R2 = 0.24). When accounting for surface sampling, CIST values only explained 46 % of the variability in F355 data in 2012 (R2 = 0.46) and 56 % in 2013 (R2 = 0.56). Residuals around these best-fit regression lines were ±25 Gmax, indicating that the CIST cannot accurately predict impact attenuation values with the F355 within this range. Future research should continue to explore relationships between the F355 and CIST across diverse playing surface types and environments.
Application of a Non-Contact Laser Ultrasonic Imaging Technology for Detection Weld Defect Based on Hilbert Transform
Authors: Zeng W.
Published: February 2016

A non-contact laser ultrasonic imaging technique was proposed to detect austenitic stainless steel weld with artificial defects. Austenitic stainless steel weld was scanned by a pulsed laser, and the ultrasonic waves were received by the interferometer. The vibration images of ultrasonic waves at different locations were analyzed in detail. In order to detect the size of the damage, we use the Hilbert transform method to transform ultrasonic time-domain signals into the envelope of ultrasonic wave, and find this method can improve the effects of detection the flaw. By comparing the propagation images based on the Hilbert transform method, with the result based on the anomalous wave propagation imaging method which demonstrated that the non-contact laser ultrasonic imaging technique based on the Hilbert transform method, we can evaluate the sizes of the weld damages. Hence, we proposed the ultrasonic propagation imaging approach for automatic inspection in manufacturing.
Percolation Effect on the Piezoresistivity of Carbon Nanotube/Cement Composite as a Stress Self-Sensing Material
Authors: Qiao B. , Xie N. , Meng J. , Yan T. , Feng L. , Zhong J.
Published: February 2016

Self-sensing material is one of the most important components of smart construction. As a promising stress self-sensing material, carbon nanotube (CNT)/cement composite has been widely studied in the past decade. The stress self-sensing performance, which is reflected by the piezoresistivity of the CNT/cement composite, can be determined by several factors, such as CNT dispersion, water/binder ratio, or loading directions. Although these factors have been systematically investigated to demonstrate their effects on the self-sensing performance of CNT/cement composite, the variation of the percolation networks of CNT in the cement matrix, which is another important factor that determines the piezoresistivity of the CNT/cement composite, was barely discussed before. In this study, the variation of the CNT percolation network in cement matrix under compression loading was calculated based on the percolation theory; and the piezoresistivity of the CNT/cement composite below and above the percolation threshold was analyzed from the perspective of the effective percolation networks of CNT in the CNT/cement composite. Furthermore, the mechanism of the piezoresistivity variation was elucidated via calculating the percolation backbone density. This study not only gives a basic introduction to calculate the effective percolation networks of CNT in the cement matrix, but also shed light on how to obtain a CNT/cement composite with a stable stress self-sensing performance.
Porosity Characterization in Interfacial Transition Zone Using Dual CT Scans
Authors: Cui D. , Sun W. , Wan K. , Banthia N.
Published: February 2016

The interfacial transition zone tends to be the weakest link in cement-based materials. This zone is widely believed to be less dense compared with the bulk hydrated cement matrix and is often the location where the failure first initiates. Because of its increased porosity, the interface also acts as a preferential path for transport of deleterious fluids. Understanding the microstructure of the interface, therefore, is of high importance. In this paper, a new technique is developed to calculate the width, as well as the average porosity, of the interface. The method relies on computer tomography (CT). Compared with the traditional porosity-measurement methods, the proposed dual-scan method is non-destructive, and, to a great extent, preserves the initial microstructure of the interface, thereby providing an undisturbed characterization. This article further attests that the dual-scan method can mitigate the deficiency of traditional CT scan in terms of its limited resolution.
Determination of Dynamic Modulus Values of Asphalt Mixtures Using Impact Resonance Testing of Thin Disk Specimens
Authors: Kim D. , Kim Y. R.
Published: February 2016

The impact resonance (IR) test is a nondestructive test method that is used to characterize the linear viscoelastic behavior of asphalt concrete. This method is preferred over other methods because the setup of the IR test is simpler, more efficient, and less expensive than standard axial compression dynamic modulus (|E*|) tests. Researchers originally developed the IR test method for cylindrical specimens of asphalt mixtures and concluded that this method can serve as an alternative to |E*| tests. However, the geometry (100 mm in diameter by 150 mm in height) of the cylindrical specimens used in these tests prohibits the use of IR tests for field cores. Therefore, researchers began to consider thin disk-shaped specimens for IR testing because thinner geometry of such specimens better represents slices of field cores. In this study, a test procedure was developed to evaluate the use of thin disk-shaped specimens for IR tests in order to determine the |E*| values of asphalt mixtures. The IR test protocol was optimized using 2 IR test methods (referred to as Case 1 and Case 2 in this work) under various test conditions to ensure the highest possible quality of the data. Optimal test methods were proposed based on the repeatability and variability of the resonant frequency and phase angle data and the ability of the different test conditions to provide data that best match the |E*| values obtained from standard axial compression |E*| tests. The results demonstrate that the |E*| values of thin disk-shaped specimens determined from the optimized IR tests are similar to the |E*| values of long cylindrical specimens determined from conventional |E*| AASHTO T 342-11 tests and IR tests.
Analysis of Masked Data in a Series System Subjected to Sources of Shocks Under Type I Progressive Hybrid Censoring
Authors: Cai J. , Shi Y. , Liu B.
Published: February 2016

In this paper, we consider the statistical analysis of masked data based on the fatal shock model under type I progressive hybrid censoring. It is assumed that the time of shock follows Weibull distribution. Maximum-likelihood estimators for the unknown parameters are obtained by solving a one-dimensional optimization problem. Approximate maximum-likelihood estimators have been proposed based on a Taylor series expansion, and they have explicit expressions. In addition, the Bayesian approach, combined with Gibbs sampling, are developed based on the assumption that the shape parameter has a log-concave function, and for the given shape parameter, the scale parameters have Gamma-Dirichlet priors. Finally, Monte Carlo simulations are performed to compare the performances of the proposed methods under different progressive censoring schemes and masking levels.
Aggregate Gradation Influence on Grouting Results and Mix Design of Asphalt Mixture Skeleton for Semi-Flexible Pavement
Authors: Hou Shuguang , Xu Tao , Huang Kai
Published: February 2016

In this study, to design a satisfactory asphalt mixture skeleton for semi-flexible pavement (SFP), the effects of aggregate gradation on grouting results of porous asphalt mixture were analyzed based on the test results of 22 aggregate gradations. Moreover, the mix design method of asphalt mixture skeleton was also discussed. Results indicated that the grouting effects of asphalt mixture skeleton were affected by its internal void interconnectivity, including the morphological characteristics, structure, and size of pores, instead of the initial void volume (VV). The grouting effects of asphalt mixture skeleton were influenced by the fine aggregate at the specific particle size levels. An increase in the mixing proportion of coarse aggregates could improve the grouting effects. A valid mix design approach was developed to prepare the asphalt mixture skeleton of SFP. Finally, engineering properties of the grouted mixture specimens were validated. It was concluded that the aggregation gradation design was a very important aspect in effecting the grouting results of an asphalt mixture skeleton. Furthermore, the aggregate gradation should be selected to facilitate the cement slurry to permeate in full thickness of the asphalt mixture skeleton layer. This could be used to direct the design of asphalt mixture skeleton toward lessening field failures on the SFP.
Flexural Strength Tests of Brittle Materials: Selecting the Number of Specimens and Determining Confidence Limits for Weibull Parameters
Authors: McCool J. I.
Published: February 2016

The flexural strength of brittle materials has been found to follow the two-parameter Weibull distribution. This paper describes a simple method of estimating the Weibull modulus and characteristic strength that allows for the computation of confidence intervals that will contain the true values within a specifiable level of confidence. The sample size needed to meet the experimenter's precision requirements is determined. A sample of flexural strength data from the literature is used to illustrate all of the computations. The precision of the method is compared to that of the method of maximum likelihood. It is found to be inferior to maximum likelihood for estimating the Weibull modulus but quite comparable for estimating the scale parameter.
Comparative Biaxial Flexural Behavior of Ultra-High-Performance Fiber-Reinforced Concrete Panels Using Two Different Test and Placement Methods
Authors: Yoo Doo-Yeol , Banthia Nemkumar , Zi Goangseup , Yoon Young-Soo
Published: February 2016

In order to investigate the effects of fiber length, placement method, and test method on the biaxial flexural behaviors of ultra-high-performance fiber-reinforced concrete (UHPFRC), several UHPFRC panels with two different fiber lengths (Lf of 13 and 19.5 mm) were fabricated using two different placement methods (placing concrete at the center and the edge) and were then tested by two different test methods (ASTM C1550-12a and a novel biaxial flexure test (BFT)). Image analysis was also performed to quantitatively investigate the fiber distribution characteristics according to the fiber length and placement method and to thoroughly analyze the experimental results. The first cracking strength and corresponding toughness were found to be insignificantly influenced by the fiber length, placement method, and test method, but the panels with longer fibers and with concrete placed at the center (in the maximum moment region) were found to have higher biaxial flexural strength, deflection capacity, and toughness after a deflection of 2.5 mm (d2.5). The panels tested by the BFT method showed lower flexural strength, more cracks with a random distribution, and higher deviation in flexural performances than those tested by ASTM C1550. These test results were verified by evaluating the fiber distribution characteristics (i.e., the number of fibers per unit area, fiber orientation, and fiber dispersion) at localized crack surfaces by using the image analysis technique.
Application of Heat of Wetting for Determination of Soil-Specific Characteristics of Fine-Grained Soils
Authors: Kadali Srinivas , Susha Lekshmi S. U. , Singh D. N. , Shojaei Baghini Maryam
Published: February 2016

Conventionally, particle size distribution characteristics and consistency limits have been used to characterize fine-grained soils. However, these schemes of soil characterization are devoid of several other soil-specific parameters (viz., specific surface area, specific gravity, weight loss during heating, heat produced during the interaction of soil with water, chemical and mineralogical composition, zeta potential, cation-exchange capacity, and reactivity) that imbibe in them physical, chemical, mineralogical, and thermal characteristics or, in short, the “overall characteristics” of the soil. These characteristics are also useful to define soils with pollutants and contaminants, which result from rapid and indiscriminate industrialization. Hence, characterization of the soil based on its “heat of wetting,” which imbibes the specific characteristics of the soil and is measured by the percentage increase in temperature (PIT) when soil-water interaction occurs, appears to be quite prudent and a novel idea or hypothesis. With this in view and to develop a soil characterization scheme, soils of completely different characteristics were allowed to interact with water in a calorimeter, and the PIT was measured precisely by employing a thermocouple. The PIT and various soil-specific parameters when correlated with each other yielded well-defined relationships. Utility of these relationships for a quick and easy characterization of fine-grained soils has also been demonstrated in this study.
Mechanical Responses of Rock Joints With Regular Asperities Under Various Shear Rates Investigated by Double Shear Test
Authors: Li H. H.
Published: February 2016

To study the mechanical responses of rock joints within a wide range of shear rates, this study develops a horizontal gripping mechanism to improve a double shear test device. Artificial rock joints, including planar and regular asperities with dip angles of 15° and 30°, are produced for conducting double shear tests under constant normal load within the shear rate range of 10−2–101 mm/s. Experimental results demonstrate that, though normalized by applied normal stress, the shear stiffness of the planar joints has a semi-logarithmic linear relationship with normalized shear rates. For rock joints with regular asperities, the shear rate, asperity dip angle, and normal stress influence the failure modes of asperities. When the shear rate is lower than the threshold shear rate, the asperity dip angles after the shear process and the peak dilation angles of the 15° regular joints increase with increasing the shear rate, whereas these two parameters tend to decrease in the cases of the 30° regular joints. The peak friction angles of both planar and regular rock joints have a semi-logarithmic linear relationship with normalized shear rates. The increasing peak friction angles of rock joints at different shear rates after sliding or local cut-off failures are derived mainly from increased basic friction angles. Both the basic friction angles of rock joints and the shear strength of asperities rise as the shear rate increases when asperity cut-off occurs. However, the quantitative effect of these two factors on the increase of peak friction angle requires further study.
Effect of Adhesion and Cohesion on Ductile Fracture in Cylindrical Upsetting Process
Authors: Chirala H. K. , Davidson M. J. , Cherukuri N. , Raju P. S. , Rao G. S.
Published: February 2016

The lubricants employed at the die/billet interface reduce the adhesion and improve the formability of the AA 2014-T6 billets by avoiding cracks. The friction factor obtained from the ring compression test for different lubricants was correlated with the hypothesis of ductile fracture based on void failures to examine the damage rate with the increasing strain. Mohr–Coulomb criterion was employed for observing the cohesive failure for different aluminum alloys. The fitting parameters in the Mohr–Coulomb criterion were varied to study the influence of the process parameters on the fracture strain. The hardness variation in the billets for different stress triaxialities and Lode parameters was also investigated by constitutive modeling of the hardness with the equivalent strain.
Strength and Fracture Characterization of a Novel Polyurethane Adhesive for the Automotive Industry
Authors: Faneco T. M. S. , Campilho R. D. S. G. , Silva F. J. G. , Lopes R. M.
Published: February 2016

Adhesive bonding by structural adhesives has been used for several decades, helping to solve various problems related to the conventional joining techniques, such as welding, riveting, or bolting. Adhesive joints present less structural weight, lower manufacturing cost, the possibility to join different materials, and high fatigue strength. The increasing use of composite materials also helped to the growing use of adhesive joints, since these do not break the reinforcing fibers' continuity. An adhesive joint is mainly subjected to peel and shear loads. However, the knowledge of the tensile (E) and shear (G) moduli of the adhesive, and its tensile (σf) and shear failure strengths (τf), is not enough to predict the joint behavior. In fact, the critical strain energy release rate in tension (GIc) and shear (GIIc) are equally necessary for advanced modelling techniques such as cohesive zone modelling (CZM). This work aimed to study a novel structural polyurethane adhesive to obtain material property data that can be further used for the strength prediction of bonded structures. With this purpose, 4 tests were performed: tensile testing to bulk specimens, shear testing with thick adherend shear tests (TAST), double-cantilever beam (DCB), and end-notched flexure (ENF) tests. These tests will allow values to be determined for the mechanical and fracture properties of the adhesive in tension and shear. The parameters to predict the strength of adhesive joints with this adhesive by various methods were provided, ranging from the easy to apply analytical methods to the most advanced numerical methods available nowadays. A detailed comparison is also undertaken with an adhesive of the same family. The obtained results were in close agreement with the few data provided by the manufacturer (E and σf), while fracture data was also provided with a good agreement between data reduction schemes.
AFM Evaluation of Pre-Straining Degree Effects on the Dimensions of Stress Induced Martensite Plates in Fe-Mn-Si Based SMAs
Authors: Suru M.-G. , Lohan N.-M. , Mihalache E. , Pricop B. , Mocanu M. , Bujoreanu L.-G.
Published: February 2016

By means of atomic force microscopy (AFM) measurements, the evolution of surface relief characteristics of stress induced martensite plates was investigated on the surface of polished Fe-14Mn-6Si-9Cr-5Ni and Fe–28Mn–6Si–5Cr (mass. %) shape memory alloys (SMAs), subjected to various pre-straining degrees. Pre-straining degree was chosen as an independent variable, considering its influence on the reverse transformation of martensite. The specimens were cast by means of a levitation induction furnace and hot rolled to 1 mm-thickness in order to better reveal the shape memory phenomena. The specimens, cut by spark erosion to “dog-bone” shapes, were pre-strained by means of a tensile testing machine at room temperature (RT). The gauges of elongated specimens were analyzed by AFM. Qualitative 2D analyses were performed on AFM micrographs. Quantitative evaluations were based on systematic dimensional measurements of martensite profiles, allowing the determination of the average values of plate widths and heights for four pre-straining degrees of the two SMA systems under study. The variation tendencies of average values of martensite plate widths and heights with increasing the pre-straining were examined under the form of increasing rates of the plate widths and heights. The results show that, for the two SMA systems studied, the average widths and heights of stress-induced martensite plates varied between 80 and 188 nm for Fe-14Mn-6Si-9Cr-5Ni and between 101 and 192 nm for Fe-28Mn-6Si-5Cr. These dimensions experienced an increasing tendency with pre-straining degree, with a rate of about 30 nm/ % pre-strain.
Results for a Fuel Cell System Consisting of an SOFC Fed by an Adiabatic Pre-Reforming Fuel Processor With European Standard Road Diesel
Authors: Kleinohl N. , Hansen J. B. , Nehter P. , Modarresi H. , Bauschulte A. , vom Schloß J. , Lucka K.
Published: February 2016

In the near future, ships will need more efficient power generation technologies for auxiliary power supply than those used currently. In the project SchiffsIntegration BrennstoffZelle (SchIBZ), a fuel cell system is being developed to increase the electrical efficiency of on-board power supply systems. In order to avoid the limitation of hydrogen storage, the on-site fuel processing of hydrocarbons offered an opportunity for the hydrogen supply of fuel cell systems to be operated in remote locations. As fuel standard European road diesel was processed with the process of adiabatic pre-reforming, a steam-reforming derivate. A solid oxide fuel cell (SOFC) was coupled with this fuel processor and was fed with standard European diesel fuel. Two flexible test rigs were developed to test the fuel processor and the SOFC either combined or independently. During combined operation, the SOFC modules were fed with feedstock gas from the fuel processor, which ran on standard European diesel fuel. Combined operation of both test rigs at steady state was achieved for more than 1000 h. For the whole experimental runtime, the fuel processor delivered sufficient feedstock quality for the SOFC, and no significant voltage degradation (about 0.5 %) of the SOFC modules was observed over 1000 h of operation. This low value of degradation is known for the operation of SOFC with pure hydrogen and methane without impurities.
Persistent Electrical Activity in Primary Nociceptors after Spinal Cord Injury Is Maintained by Scaffolded Adenylyl Cyclase and Protein Kinase A and Is Associated with Altered Adenylyl Cyclase Regulation
Authors: Bavencoffe Alexis , Li Yong , Wu Zizhen , Yang Qing , Herrera Juan , Kennedy Eileen J. , Walters Edgar T. , Dessauer Carmen W.
Published: February 2016

Little is known about intracellular signaling mechanisms that persistently excite neurons in pain pathways. Persistent spontaneous activity (SA) generated in the cell bodies of primary nociceptors within dorsal root ganglia (DRG) has been found to make major contributions to chronic pain in a rat model of spinal cord injury (SCI) (Bedi et al., 2010; Yang et al., 2014). The occurrence of SCI-induced SA in a large fraction of DRG neurons and the persistence of this SA long after dissociation of the neurons provide an opportunity to define intrinsic cell signaling mechanisms that chronically drive SA in pain pathways. The present study demonstrates that SCI-induced SA requires continuing activity of adenylyl cyclase (AC) and cAMP-dependent protein kinase (PKA), as well as a scaffolded complex containing AC5/6, A-kinase anchoring protein 150 (AKAP150), and PKA. SCI caused a small but significant increase in the expression of AKAP150 but not other AKAPs. DRG membranes isolated from SCI animals revealed a novel alteration in the regulation of AC. AC activity stimulated by Ca2+-calmodulin increased, while the inhibition of AC activity by Gαi showed an unexpected and dramatic decrease after SCI. Localized enhancement of the activity of AC within scaffolded complexes containing PKA is likely to contribute to chronic pathophysiological consequences of SCI, including pain, that are promoted by persistent hyperactivity in DRG neurons.

SIGNIFICANCE STATEMENTChronic neuropathic pain is a major clinical problem with poorly understood mechanisms and inadequate treatments. Recent findings indicate that chronic pain in a rat SCI model depends upon hyperactivity in dorsal root ganglia (DRG) neurons. Although cAMP signaling is involved in many forms of neural plasticity, including hypersensitivity of nociceptors in the presence of inflammatory mediators, our finding that continuing cAMP-PKA signaling is required for persistent SA months after SCI and long after isolation of nociceptors is surprising. The dependence of ongoing SA upon AKAP150 and AC5/6 was unknown. The discovery of a dramatic decrease in Gαi inhibition of AC activity after SCI is novel for any physiological system and potentially has broad implications for understanding chronic pain mechanisms.
Remyelinating Oligodendrocyte Precursor Cell miRNAs from the Sfmbt2 Cluster Promote Cell Cycle Arrest and Differentiation
Authors: Kuypers Nicholas J. , Bankston Andrew N. , Howard Russell M. , Beare Jason E. , Whittemore Scott R.
Published: February 2016

Oligodendrocyte (OL) loss contributes to the functional deficits underlying diseases with a demyelinating component. Remyelination by oligodendrocyte progenitor cells (OPCs) can restore these deficits. To understand the role that microRNAs (miRNAs) play in remyelination, 2′,3′-cyclic-nucleotide 3′-phosphodiesterase-EGFP+mice were treated with cuprizone, and OPCs were sorted from the corpus callosum. Microarray analysis revealed that Sfmbt2 family miRNAs decreased during cuprizone treatment. One particular Sfmbt2 miRNA, miR-297c-5p, increased during mouse OPC differentiationin vitroand during callosal developmentin vivo. When overexpressed in both mouse embryonic fibroblasts and rat OPCs (rOPCs), cell cycle analysis revealed that miR-297c-5p promoted G1/G0arrest. Additionally, miR-297c-5p transduction increased the number of O1+rOPCs during differentiation. Luciferase reporter assays confirmed that miR-297c-5p targets cyclin T2 (CCNT2), the regulatory subunit of positive transcription elongation factor b, a complex that inhibits OL maturation. Furthermore, CCNT2-specific knockdown promoted rOPC differentiation while not affecting cell cycle status. Together, these data support a dual role for miR-297c-5p as both a negative regulator of OPC proliferation and a positive regulator of OL maturation via its interaction with CCNT2.

SIGNIFICANCE STATEMENTThis work describes the role of oligodendrocyte progenitor cell (OPC) microRNAs (miRNAs) during remyelination and developmentin vivoand differentiationin vitro. This work highlights the importance of miRNAs to OPC biology and describes miR-297c-5p, a novel regulator of OPC function. In addition, we identified CCNT2 as a functional target, thus providing a mechanism by which miR-297c-5p imparts its effects on differentiation. These data are important, given our lack of understanding of OPC miRNA regulatory networks and their potential clinical value. Therefore, efforts to understand the role of miR-297c-5p in pathological conditions and its potential for facilitating repair may provide future therapeutic strategies to treat demyelination.
Human Visual Cortex Responses to Rapid Cone and Melanopsin-Directed Flicker
Authors: Spitschan Manuel , Datta Ritobrato , Stern Andrew M. , Brainard David H. , Aguirre Geoffrey K.
Published: February 2016

Signals from cones are recombined in postreceptoral channels [luminance, L + M; red-green, L − M; blue-yellow, S − (L + M)]. The melanopsin-containing retinal ganglion cells are also active at daytime light levels and recent psychophysical results suggest that melanopsin contributes to conscious vision in humans. Here, we measured BOLD fMRI responses to spectral modulations that separately targeted the postreceptoral cone channels and melanopsin. Responses to spatially uniform (27.5° field size, central 5° obscured) flicker at 0.5, 1, 2, 4, 8, 16, 32, and 64 Hz were recorded from areas V1, V2/V3, motion-sensitive area MT, and the lateral occipital complex. In V1 and V2/V3, higher temporal sensitivity was observed to L + M + S (16 Hz) compared with L − M flicker (8 Hz), consistent with psychophysical findings. Area MT was most sensitive to rapid (32 Hz) flicker of either L + M + S or L − M. We found S cone responses only in areas V1 and V2/V3 (peak frequency: 4–8 Hz). In addition, we studied an L + M modulation and found responses that were effectively identical at all temporal frequencies to those recorded for the L + M + S modulation. Finally, we measured the cortical response to melanopsin-directed flicker and compared this response with control modulations that addressed stimulus imprecision and the possibility of stimulation of cones in the shadow of retinal blood vessels (penumbral cones). For our stimulus conditions, melanopsin flicker did not elicit a cortical response exceeding that of the control modulations. We note that failure to control for penumbral cone stimulation could be mistaken for a melanopsin response.

SIGNIFICANCE STATEMENTThe retina contains cone photoreceptors and ganglion cells that contain the photopigment melanopsin. Cones provide brightness and color signals to visual cortex. Melanopsin influences circadian rhythm and the pupil, but its contribution to cortex and perception is less clear. We measured the response of human visual cortex with fMRI using spectral modulations tailored to stimulate the cones and melanopsin separately. We found that cortical responses to cone signals vary systematically across visual areas. Differences in temporal sensitivity for achromatic, red-green, and blue-yellow stimuli generally reflect the known perceptual properties of vision. We found that melanopsin signals do not produce a measurable response in visual cortex at temporal frequencies between 0.5 and 64 Hz at daytime light levels.
Nonspatial Sequence Coding in CA1 Neurons
Authors: Allen Timothy A. , Salz Daniel M. , McKenzie Sam , Fortin Norbert J.
Published: February 2016

The hippocampus is critical to the memory for sequences of events, a defining feature of episodic memory. However, the fundamental neuronal mechanisms underlying this capacity remain elusive. While considerable research indicates hippocampal neurons can represent sequences of locations, direct evidence of coding for the memory of sequential relationships among nonspatial events remains lacking. To address this important issue, we recorded neural activity in CA1 as rats performed a hippocampus-dependent sequence-memory task. Briefly, the task involves the presentation of repeated sequences of odors at a single port and requires rats to identify each item as “in sequence” or “out of sequence”. We report that, while the animals' location and behavior remained constant, hippocampal activity differed depending on the temporal context of items—in this case, whether they were presented in or out of sequence. Some neurons showed this effect across items or sequence positions (general sequence cells), while others exhibited selectivity for specific conjunctions of item and sequence position information (conjunctive sequence cells) or for specific probe types (probe-specific sequence cells). We also found that the temporal context of individual trials could be accurately decoded from the activity of neuronal ensembles, that sequence coding at the single-cell and ensemble level was linked to sequence memory performance, and that slow-gamma oscillations (20–40 Hz) were more strongly modulated by temporal context and performance than theta oscillations (4–12 Hz). These findings provide compelling evidence that sequence coding extends beyond the domain of spatial trajectories and is thus a fundamental function of the hippocampus.

SIGNIFICANCE STATEMENTThe ability to remember the order of life events depends on the hippocampus, but the underlying neural mechanisms remain poorly understood. Here we addressed this issue by recording neural activity in hippocampal region CA1 while rats performed a nonspatial sequence memory task. We found that hippocampal neurons code for the temporal context of items (whether odors were presented in the correct or incorrect sequential position) and that this activity is linked with memory performance. The discovery of this novel form of temporal coding in hippocampal neurons advances our fundamental understanding of the neurobiology of episodic memory and will serve as a foundation for our cross-species, multitechnique approach aimed at elucidating the neural mechanisms underlying memory impairments in aging and dementia.
Estradiol-Mediated Spine Changes in the Dorsal Hippocampus and Medial Prefrontal Cortex of Ovariectomized Female Mice Depend on ERK and mTOR Activation in the Dorsal Hippocampus
Authors: Tuscher Jennifer J. , Luine Victoria , Frankfurt Maya , Frick Karyn M.
Published: February 2016

Dendritic spine plasticity underlies the formation and maintenance of memories. Both natural fluctuations and systemic administration of 17β-estradiol (E2) alter spine density in the dorsal hippocampus (DH) of rodents. DH E2infusion enhances hippocampal-dependent memory by rapidly activating extracellular signal-regulated kinase (ERK)-dependent signaling of mammalian target of rapamycin (mTOR), a key protein synthesis pathway involved in spine remodeling. Here, we investigated whether infusion of E2directly into the DH drives spine changes in the DH and other brain regions, and identified cell-signaling pathways that mediate these effects. E2significantly increased basal and apical spine density on CA1 pyramidal neurons 30 min and 2 h after infusion. DH E2infusion also significantly increased basal spine density on pyramidal neurons in the medial prefrontal cortex (mPFC) 2 h later, suggesting that E2-mediated activity in the DH drives mPFC spinogenesis. The increase in CA1 and mPFC spine density observed 2 h after intracerebroventricular infusion of E2was blocked by DH infusion of an ERK or mTOR inhibitor. DH E2infusion did not affect spine density in the dentate gyrus or ventromedial hypothalamus, suggesting specific effects of E2on the DH and mPFC. Collectively, these data demonstrate that DH E2treatment elicits ERK- and mTOR-dependent spinogenesis on CA1 and mPFC pyramidal neurons, effects that may support the memory-enhancing effects of E2.

SIGNIFICANCE STATEMENTAlthough systemically injected 17β-estradiol (E2) increases CA1 dendritic spine density, the molecular mechanisms regulating E2-induced spinogenesisin vivoare largely unknown. We found that E2infused directly into the dorsal hippocampus (DH) increased CA1 spine density 30 min and 2 h later. Surprisingly, DH E2infusion also increased spine density in the medial prefrontal cortex (mPFC), suggesting that estrogenic regulation of the DH influences mPFC spinogenesis. Moreover, inhibition of ERK and mTOR activation in the DH prevented E2from increasing DH and mPFC spines, demonstrating that DH ERK and mTOR activation is necessary for E2-induced spinogenesis in the DH and mPFC. These findings provide novel insights into the molecular mechanisms through which E2mediates dendritic spine density in CA1 and mPFC.
Principles Governing DNA Methylation during Neuronal Lineage and Subtype Specification
Authors: Sharma Ali , Klein Shifra Liba , Barboza Luendreo , Lodhi Niraj , Toth Miklos
Published: February 2016

Although comprehensively described during early neuronal development, the role of DNA methylation/demethylation in neuronal lineage and subtype specification is not well understood. By studying two distinct neuronal progenitors as they differentiate to principal neurons in mouse hippocampus and striatum, we uncovered several principles governing neuronal DNA methylation during brain development. (1) The program consists of three stages: an initial genome-wide methylation during progenitor proliferation is followed by loss of methylation during the transition of regional progenitors to “young” hippocampal/striatal neurons, which is then reversed by gain in methylation during maturation to subtype-specific neurons. (2) At the first two stages, gain and loss of methylation are limited to CpGs, whereas during the third maturation stage, methylation also occurs at non-CpG sites in both lineages. (3) Methylation/demethylation, similar to transcription, are initially highly similar in the two lineages, whereas diversification in methylation and transcription during maturation creates subtype-specific methylation differences. (4) Initially, methylation targets all genomic locations, whereas later, during early and late differentiation, the preferred targets are intronic/intergenic sequences with enhancer-like activity. (5) Differentially methylated genes are enriched in sequential neurodevelopmental functions (such as progenitor proliferation, migration, neuritogenesis, and synaptic transmission); upregulated genes represent current and consecutive stage-specific functions, and downregulated genes represent preceding functions that are no longer required. The main conclusion of our work is that the neuronal methylation/demethylation program is predominantly developmental with minimal lineage specificity, except in the final stage of development when neuron subtype-specific differences also emerge.

SIGNIFICANCE STATEMENTOur work is the first to describe a set of relatively simple rules that govern DNA methylation and demethylation in neuronal developmentin vivo. By dividing neurodevelopment to three major stages and applying rules to each of them, we created a matrix that comprehensively describes DNA methylation/demethylation events in two neuronal lineages, with a total of 10 cell types spanning the entire neurodevelopment. Beyond increasing our understanding of the epigenetic regulation of normal development, our work will be useful in deciphering how environmental perturbations, such as gestational toxins, drugs, stress, infection, and offspring neglect/maltreatment, interfere with the developmental methylation program.