bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of Phase Transformation and Mechanical Properties of 55CrMo Steel during Induction Hardening
Authors: Li Huiping , Zhou Weilu , Liu Haijuan , Li Zhichao , He Lianfang 
Published: January 2019

Abstract
To optimize the parameters of induction hardening and improve the surface hardness distribution of ball screw, the effects of the induction heating temperature on the microstructure and mechanical properties of 55CrMo steel were investigated. The specimens were heated up to 800°C, 850°C, 900°C, 950°C, 1,000°C, or 1,100°C by the induction heating power supply. Microstructural characterization of specimens was performed using an optical microscope and a high-resolution scanning electron microscope. The volume fraction of the retained austenite was measured using an X-ray diffractometer. The mechanical properties were evaluated by a microhardness tester and an electronic universal testing machine. The results show that the volume fraction of martensite in the hardened specimen increases with the increasing of heating temperature. A mixed microstructure consisting of ferrite + pearlite, bainite, and martensite is produced because of the nonfully and nonuniform austenitic state of original microstructure as the heating temperature is at 800°C. A full martensite can be produced as the heating temperature is more than 850°C. The volume fraction of retained austenite in the hardened specimen is lower when the heating temperature is in the range of 850°C–950°C; nonetheless, the volume fraction of retained austenite increases, and the tensile strength of the specimen reduces with the increasing of the heating temperature when the heating temperature is more than 950°C. The 55CrMo steel has good microstructure and mechanical properties and can meet the requirements of ball screw when the induction heating temperature is in the range of 850°C–950°C.
Light-Activated ROS Production Induces Synaptic Autophagy
Authors: Hoffmann Sheila , Orlando Marta , Andrzejak Ewa , Bruns Christine , Trimbuch Thorsten , Rosenmund Christian , Garner Craig C. , Ackermann Frauke 
Published: January 2019

The regulated turnover of synaptic vesicle (SV) proteins is thought to involve the ubiquitin-dependent tagging and degradation through endo-lysosomal and autophagy pathways. Yet, it remains unclear which of these pathways are used, when they become activated, and whether SVs are cleared en masse together with SV proteins or whether both are degraded selectively. Equally puzzling is how quickly these systems can be activated and whether they function in real-time to support synaptic health. To address these questions, we have developed an imaging-based system that simultaneously tags presynaptic proteins while monitoring autophagy. Moreover, by tagging SV proteins with a light-activated ROS generator, Supernova, it was possible to temporally control the damage to specific SV proteins and assess their consequence to autophagy-mediated clearance mechanisms and synaptic function. Our results show that, in mouse hippocampal neurons of either sex, presynaptic autophagy can be induced in as little as 5–10 min and eliminates primarily the damaged protein rather than the SV en masse. Importantly, we also find that autophagy is essential for synaptic function, as light-activated damage to, for example, Synaptophysin only compromises synaptic function when autophagy is simultaneously blocked. These data support the concept that presynaptic boutons have a robust highly regulated clearance system to maintain not only synapse integrity, but also synaptic function.SIGNIFICANCE STATEMENTThe real-time surveillance and clearance of synaptic proteins are thought to be vital to the health, functionality, and integrity of vertebrate synapses and are compromised in neurodegenerative disorders, yet the fundamental mechanisms regulating these systems remain enigmatic. Our analysis reveals that presynaptic autophagy is a critical part of a real-time clearance system at synapses capable of responding to local damage of synaptic vesicle proteins within minutes and to be critical for the ongoing functionality of these synapses. These data indicate that synapse autophagy is not only locally regulated but also crucial for the health and functionality of vertebrate presynaptic boutons.
Voltage-Dependent Membrane Properties Shape the Size But Not the Frequency Content of Spontaneous Voltage Fluctuations in Layer 2/3 Somatosensory Cortex
Authors: Fernandez Fernando R. , Noueihed Jad , White John A. 
Published: January 2019

Under awake and idling conditions, spontaneous intracellular membrane voltage is characterized by large, synchronous, low-frequency fluctuations. Although these properties reflect correlations in synaptic inputs, intrinsic membrane properties often indicate voltage-dependent changes in membrane resistance and time constant values that can amplify and help to generate low-frequency voltage fluctuations. The specific contribution of intrinsic and synaptic factors to the generation of spontaneous fluctuations, however, remains poorly understood. Using visually guided intracellular recordings of somatosensory layer 2/3 pyramidal cells and interneurons in awake male and female mice, we measured the spectrum and size of voltage fluctuation and intrinsic cellular properties at different voltages. In both cell types, depolarizing neurons increased the size of voltage fluctuations. Amplitude changes scaled with voltage-dependent changes in membrane input resistance. Because of the small membrane time constants observed in both pyramidal cells and interneuron cell bodies, the low-frequency content of membrane fluctuations reflects correlations in the synaptic current inputs rather than significant filtering associated with membrane capacitance. Further, blocking synaptic inputs minimally altered somatic membrane resistance and time constant values. Overall, these results indicate that spontaneous synaptic inputs generate a low-conductance state in which the amplitude, but not frequency structure, is influenced by intrinsic membrane properties.SIGNIFICANCE STATEMENTIn the absence of sensory drive, cortical activity in awake animals is associated with self-generated and seemingly random membrane voltage fluctuations characterized by large amplitude and low frequency. Partially, these properties reflect correlations in synaptic input. Nonetheless, neurons express voltage-dependent intrinsic properties that can potentially influence the amplitude and frequency of spontaneous activity. Using visually guided intracellular recordings of cortical neurons in awake mice, we measured the voltage dependence of spontaneous voltage fluctuations and intrinsic membrane properties. We show that voltage-dependent changes in membrane resistance amplify synaptic activity, whereas the frequency of voltage fluctuations reflects correlations in synaptic inputs. Last, synaptic activity has a small impact on intrinsic membrane properties in both pyramidal cells and interneurons.
Errors in Action Timing and Inhibition Facilitate Learning by Tuning Distinct Mechanisms in the Underlying Decision Process
Authors: Dunovan Kyle , Verstynen Timothy 
Published: January 2019

Goal-directed behavior requires integrating action selection processes with learning systems that adapt control using environmental feedback. These functions are known to intersect at a common neural substrate with multiple known targets of plasticity (the cortico-basal ganglia-thalamic network), suggesting that feedback signals have a multifaceted impact on future decisions. Using a hybrid of accumulation-to-bound decision models and reinforcement learning, we modeled the performance of humans in a stop signal task where participants (N 75: 37 males, 38 females) learned the prior distribution of the timing of a stop signal through trial-and-error feedback. Changes in the drift rate of the action execution process were driven by errors in action timing, whereas adaptation in the boundary height served to increase caution following failed stops. These findings highlight two interactive learning mechanisms for adapting the control of goal-directed actions based on dissociable dimensions of feedback error.SIGNIFICANCE STATEMENTMany complex behavioral goals rely on the ability to regulate the timing of action execution while also maintaining enough control to cancel actions in response to “Stop” cues in the environment. Here we examined how these fundamental components of behavior become tuned to the control demands of the environment by combining principles of reinforcement learning with accumulation-to-bound models. Model fits to behavioral data in an adaptive stop signal task revealed two adaptive mechanisms: (1) timing error-related changes in the rate of the execution signal; and (2) an increase in the execution boundary after failed stops. These findings demonstrate unique effects of timing and control errors on the underlying mechanisms of control, the rate and threshold of accumulating action signals.
Sensory Representations Supporting Memory Specificity: Age Effects on Behavioral and Neural Discriminability
Authors: Bowman Caitlin R. , Chamberlain Jordan D. , Dennis Nancy A. 
Published: January 2019

Older adults' difficulty in distinguishing between old and new information contributes to memory decline, which may occur because older adults are less likely than young adults to retrieve specific sensory details necessary to distinguish between similar items. In male and female human subjects, the present study measured the extent of age differences in the specificity of memory representations using a false memory paradigm in which studied items were linked to retrieval items at multiple levels of similarity. Older adults showed poorer behavioral discrimination than young adults, driven primarily by false recognition of lures that differed from targets only in perceptual details. Patterns of activation across several regions within ventral visual cortex could be used to distinguish between targets and lures when they differed in both perceptual details and a semantic label. However, of ventral visual regions, only signals in the midline occipital cortex could be used to distinguish targets from lures when they differed only in perceptual details. Although there was an overall age deficit for this neural discrimination in this region, the positive relationship between neural and behavioral discriminability did not differ across age groups. In contrast, age moderated the relationship between neural and behavioral discriminability in lateral occipital and fusiform cortices, suggesting that activation patterns within these regions represent different types of information in each age group. Therefore, the quality of perceptual signals is a key contributor to memory discrimination across age groups, with evidence that age differences in the nature of representations emerges outside early visual cortex.SIGNIFICANCE STATEMENTAge-related memory decline is due in part to older adults' difficulties in discriminating between old and new information. We tested whether this deficit arises from lack of specificity in the sensory representations underlying older adults' recognition judgments. Using pattern classification analyses in ventral visual cortices, we found that signals in a region early in the visual stream could distinguish between targets and lures at the highest level of similarity. The discriminability of targets and lures in this region was positively related to behavioral discriminability across age groups despite an overall age deficit in classification accuracy. Together, results showed that older adults' memory deficits are related to reduced discriminability of cognitive processes (old/new recognition) in portions of visual cortex.
La investigación en la educación
Authors: Aparicio Gómez Oscar Yecid , Abadía García Constanza 
Published: January 2019

El presente artículo pretende describir y analizar el proceso de introducción de la investigación como eje educativo de las TIC en una Institución Educativa del Municipio de Chía. La Institución Educativa, siguiendo la triple dimensión de su Proyecto Educativo Institucional, esto es: Investigación, Tecnología y Medio Ambiente, decidió designar el 20% destinado a las áreas complementarias u optativas, para establecer la asignatura “Metodología de la Investigación” con una hora semanal de sesenta minutos en todos los grados escolares, desde Preescolar hasta Educación Media Académica (Prejardín a Décimo grado), Igualmente, decidió crear espacios académicos específicos para “Grupos de Investigación” con una hora semanal de sesenta minutos. Los Grupos de Investigación se ofrecen en las tres secciones escolares: Educación Preescolar, Educación Básica Primaria (de Primer grado a Quinto grado), Educación Básica Secundaria y Media Académica. Preescolar dispone de un Grupo de Investigación orientado por las tutoras y que versa sobre un tema de interés específico de su edad. Las secciones de Educación Básica Primaria y Educación Básica Secundaria y Media Académica, disponen de cinco grupos cada una: Matemáticas, Ciencias Naturales, Ciencias Sociales, Lengua Castellana e Idioma Extranjero (inglés). Los estudiantes de cada sección pueden elegir el grupo al que desean pertenecer según estas cinco propuestas, y comparten el Proyecto de Investigación con los compañeros de su sección que comparten el mismo tema de interés.
Identification of Gene Variants Associated with Melanocyte Stem Cell Differentiation in Mice Predisposed for Hair Graying
Authors: Fialkowski Allison C , Levy Denise J , Watkins-Chow Dawn E , Palmer Joseph W , Darji Roshan , Tiwari Hemant K , Pavan William J , Harris Melissa L 
Published: January 2019

AbstractAge-related hair graying is caused by malfunction in the regenerative potential of the adult pigmentation system. The retention of hair color over the life of an organism is dependent on the ability of the melanocyte stem cells and their progeny to produce pigment each time a new hair grows. Age-related hair graying is variable in association with genetic background suggesting that quantitative trait loci influencing this trait can be identified. Identification of these quantitative trait loci may lead to the discovery of novel and interesting genes involved in stem cell biology and/or melanogenesis. With this in mind we developed previously a sensitized, mouse modifier screen and discovered that the DBA/1J background is particularly resistant to melanocyte stem cell differentiation in comparison to the C57BL/6J background. Melanocyte stem cell differentiation generally precedes hair graying and is observed in melanocyte stem cells with age. Using quantitative trait loci analysis, we have now identified three quantitative trait loci on mouse chromosomes 7, 13, and X that are associated with DBA/1J-mediated variability in melanocyte stem cell differentiation. Taking advantage of publicly-available mouse sequence and variant data, in silico protein prediction programs, and whole genome gene expression results we describe a short list of potential candidate genes that we anticipate to be involved in melanocyte stem cell biology in mice.
The public plate in the transnational city: Tensions among food procurement, global trade and local legislation
Authors: Sumner Jennifer , Lapalme Hayley 
Published: January 2019

Local food systems are crucial to sustainability, and one of the most effective ways to develop them is to harness the buying power of large public institutions, such as hospitals and universities. Steering public funds toward local food systems, however, is not as easy as it might appear. Institutions must navigate a maze of regulations that can become significant barriers to effecting change. In Ontario, for example, public institutions are squeezed between two contradictory policies: the Broader Public Sector Directive, which mandates a level playing field and prohibits preferential buying based on geography, and the Local Food Act, which aims to increase the consumption of local food (with a specific focus on procurement in Ontario public institutions) and to foster successful and resilient local food economies and systems. Adding to this tension, global trade treaties are drilling down to the local level, proscribing preferential procurement of local food as “protectionist” and a barrier to trade.

Public institutions are caught in the middle, wanting to purchase more local products but unwilling to risk reprisals. This paper investigates these tensions by reporting on a recent study of institutional buyers and government officials in the Toronto area to understand more thoroughly these barriers to operationalizing a local food system, while recognizing that sustainable food systems require a judicious combination of ‘local and green’ and ‘global and fair’ (Morgan 2008).
Bodies, Bollywood and Bond. The evolving image of secret agents in Hindi spy thrillers inspired by the 007 franchise
Authors: Lipka-Chudzik Krzysztof 
Published: January 2019

Independent researcherIn the 1960s, after the international commercial success of the James Bond films, many imitations and parodies of the original were made in different parts of the world. In India popular Hindi films were also inspired by the 007 franchise, beginning with the action thriller Farz in 1967. From then on a new genre was formed in the Bombay cinema: Hindi Bond films. These derivative productions were deliberately created to replicate the plot formula and narrative structure of the original Bond series. They underwent considerable development from cheap, amateurish B-movies to big budget commercial hits such as Ek Tha Tiger in 2012. Also the leading characters in Hindi Bond films, the secret agents of the Indian police and intelligence, evolved from the innocent, happy-go-lucky youngsters in the 1960s into the tough, world-weary men of action in the 2010s. One of the most important factors of this gradual change is the way the heroes’ bodies were shown on screen. The focus on the esthetics, the musculature, the physical abilities and sex appeal of the Bombay Bonds was different in every decade. This article concentrates on the evolution of Hindi Bond films: the genre as well as the leading characters.
DEBIUTUOJANTIS RAŠYTOJAS LIETUVOS KNYGŲ RINKOJE
Authors: GRINIŪTĖ ILONA 
Published: January 2019

The object of the article is the publishing of first-time authors’ books in Lithuania. The aim of the work was to explore the situation of first-time authors in the Lithuanian book market in 1990–2009 and to reveal its main problems. The tasks of the work were to define the conception of first-time author, to explore his role and its changes in the Lithuanian publishing market, to determine the ways of selecting of first-time literature books, to study the features of first-time book publishing and marketing, and to reveal the problems the publishers face in Lithuania.Analysis of literature sources and interviews has shown that first-time authors are essential for the publishers as professional writers. Furthermore, it has been discovered that there is a great demand of first-time books in the market. However, it has encouraged the development of graphomania, i.e. the writing of literarily worthless books. For this particular reason, it is important to distinguish between professional and talented first-time authors and graphomaniac writers. Besides, the work shows that the present situation of first-time book publishing is extremely related to a strong competition among the writers and to competition for publishing houses and readers. As a result, the literature is getting more and more dependent on the reader’s influence. On the one hand, such literature creates a higher level of trust between the writer and his reader; on the other hand, it strengthens the commercial side of first-time book publishing.First-time books are being produced by the bigger number of Lithuanian publishing houses. The majority of publishers produce individual first-time books while the others publish series of such books which require more effort and time constraint. Also, such books are being published by both large and small publishing companies, and the financial risk is partly transferred to national or private institutions. In addition, it has been noticed that publishers do not attempt to find or pull new authors and do not use the wide possibilities of literature festivals and contests. The research of a specific case has revealed the fact that it is not necessary to promote big advertising campaigns or use extraordinary marketing actions and money to successfully publish a first-time book. Most important are a close cooperation between the author and his publisher during the whole publishing process and, of course, a professionally written book.
Efecto bioplaguicida de extractos vegetales para el control de <i>Spodoptera frugiperda</i> en el cultivo de maíz (<i>Zea mays</i>)
Authors: Figueroa Gualteros Ana María , Castro Triviño Edgar Alejandro , Castro Salazar Hans Thielin 
Published: January 2019

El maíz es el segundo cereal de mayor producción en Colombia con un 21,9 % de la superficie total. La plaga Spodoptera frugiperda ataca la planta desde las primeras semanas de crecimiento, devorando sus hojas, tallo y granos; disminuyendo el rendimiento de los cultivos. Esta plaga se controla con el uso indiscriminado de plaguicidas sintéticos como: carbofurano, clorpirifos y atrazina. En esta investigación, los extractos de Azadirachta indica, Piper nigrum, Petiveria alliacea y sus mezclas; y los extractos de Nicotiana tabacum, Lippia alba, Allium sativum y sus mezclas se aplicaron como bioplaguicidas en plantas de maíz amarillo tradicional. Después de la tercera semana de crecimiento, los tratamientos se aplicaron dos veces al día cada tres días durante siete semanas. Las variables estudiadas fueron número de larvas muertas, altura de las plantas y daño en hojas y tallos. Las plantas tratadas crecieron dos veces más y su grado de afectación, según la escala de Mihm, fue menor que las plantas del grupo testigo. Los porcentajes de eficacia de las seis especies vegetales y sus mezclas fueron representativos (>80 %), de acuerdo con Henderson y Tilton, demostrando que estos extractos vegetales son una alternativa viable para el control de S. frugiperda.
Transforming Growth Factor Beta has Dual Effects on MMP9 and uPA Expression in HTR-8/SVneo Human Trophoblastic Cell Line
Authors: Novoa Herran Sandra Susana , Castelblanco Mariela , Sanchez-Gomez Myriam , Umaña Pérez Adriana 
Published: January 2019

Invasion of trophoblast into endometrium is vital for successful pregnancy development. MMP9 and uPA are key proteases in this process, but it is still not clear the regulation of its expression by Transforming Growth Factor Beta (TGF-β), known negative regulator of trophoblast invasion. We evaluated the effect of TGF-β on the transcriptional expression of uPA and MMP9 over time, in HTR- /SVneo trophoblast cells cultured with or without 0.5 % fetal bovine serum, via RT qPCR. The involved transcription factors and signaling pathways were analyzed in silico, using Proscan, Enrich, PCViz and WikiPathway. Results showed that that TGF-β regulates the expression of uPA and MMP9. Serum modified the nature of TGF-β’s effects on uPA expression, from negative without serum to positive with it, showing opposite effects on MMP9 expression. In silico analysis evidenced different transcription factors for each protease, some belonging to TGF-β ssignaling pathway, and crosstalk with MAPK and Wnt/β-catenin pathways. The TGF-β ddual role is discussed proposing that serum affects the cellular context. Transcriptional regulation of MMP9 and uPA by TGF-β is differential and depends on serum presence and evaluation time.