bluuebunny/crossref_metadata_2025 huggingface dataset:
Hearing capacities and otolith size in two ophidiiform species (Ophidion rocheiandCarapus acus)
Authors: Kéver Loïc , Colleye Orphal , Herrel Anthony , Romans Pascal , Parmentier Eric
Published: May 2014

Numerous studies have highlighted the diversity of fish inner ear morphology. However, the function of shape, size, and orientation of the different structures remains poorly understood. The saccule (otolithic endorgan) is considered as the principal hearing organ in fishes and it has been hypothesized that sagitta (saccular otolith) shape and size affect hearing capacities: large sagittae are thought to increase sensitivity. The sagittae of many ophidiids and carapids occupy a large volume inside the neurocranium. Hence they are of great interest to test the size hypothesis. The main aim of this study was to investigate hearing capacities and inner ear morphology in two ophidiiform species: Ophidion rochei and Carapus acus. We used a multidisciplinary approach that combines dissections, μCT-scan examinations, and auditory evoked potential technique. Carapus acus and O. rochei sagittae have similar maximal diameter, both species have larger otoliths than many non-ophidiiform species especially compared to the intra-neurocranium (INC) volume. Both species are sensitive to sounds up to 2100 Hz. Relative to the skull, O. rochei had smaller sagittae than the carapid but better hearing capacities from 300 to 900 Hz and similar sensitivities at 150 Hz and from 1200 to 2100 Hz. Results show that hearing capacities of a fish species cannot be predicted only based on sagitta size. Larger otoliths (in size relative to the skull) may have evolved mainly for performing vestibular functions in fishes, especially those ones that need to execute precise and complex movements.
Seismic Behavior of Single Layer Schwedler Domes
Authors: Yahyai Mahmood , Chahardoli Morteza
Published: May 2014

Space structures can efficiently resist seismic loads due to their lightweight, geometry, high residual strength and high redundancy. Determination of seismic response factor of space structures is essential for based on equivalent static method. Seismic behavior of single layer Schwedler domes is studied in this paper. Six domes with different spans and same number of nodes and elements as well as loading conditions are modeled using finite element method. Nonlinear static and dynamic analyses are carried out to study the seismic behavior of these domes. The force-displacement diagrams are used to obtain a formula for predicting the fundamental natural period. Using the proposed equation, response modification factor, Rw, is determined from these analyses. Moreover, ductility curves are compared at different levels of the dome. Finally, a formula is proposed for calculation of natural period of vibration and response modification factor of Schwedler domes.
The Power-to-Weight Relationships and Efficiency Improvements of Olympic Champions in Athletics, Swimming and Rowing
Authors: Stefani Ray
Published: May 2014

The goals of this article are to provide power-to-weight relationships, changes in which are predictive of changes in performance for athletics (running, jumping and throwing), for swimming and for rowing. Also this article will estimate improvements in the efficient application of power exhibited by Olympic champions in those same events over the span of the modern Games. For the former goal, the ergometer power output of an athlete, measured under laboratory conditions, is modeled in terms of training, lean body mass and a cranking term as reflected in upper arm and shoulder volume. The laws of physics are used to relate event performance to efficiency and to a power-to-weight relationship specific to each event, with both efficiency and power-to-weight raised to an exponent specific to each event. The power-to-weight relationship, in turn, depends on training and on a lean-to-total body mass relationship. The ratios of female/male Olympic championship performances are then used since significant differences may be observed. Further, the relative need for upper arm and shoulder strength may be estimated for throwing and rowing. Physiological values estimated from the ratio of female/male Olympic winning performances in athletics and swimming compare closely with actual physiological relationship, validating that analysis. Rowing relationships were also validated from performance-physiological considerations. Having validated the analysis, reliable relationships then follow between changes in the power-to-weight ratio and event performance. As to the latter goal, the observed mean improvement in winning performance per Olympiad is found for each event, leading to estimated efficiency improvement per Olympiad.
What is the Effect of Compression Garments on a Novel Kick Accuracy Task?
Authors: Lien Nancy , Steel Kylie A , Graham Kenneth , Penkala Stefania , Quinn John , Dogramaci Sera , Moresi Mark
Published: May 2014

The purpose of this study was to investigate the effect of wearing long leg compression garments (CGs) on the accuracy of elite football players performing a novel kicking task. A double-blinded, crossover, randomised and controlled laboratory trial was used to examine the contribution of the long leg CGs to kicking accuracy of a drop-punt-kick. The drop-punt-kick is a backward spinning kick often used in Australian Rules. Participants performed 10 drop-punt-kicks towards a target for each garment condition (fitted, over-sized and training shorts) with both their dominant and non-dominant leg. Kicking accuracy data was collected using a high-speed camera. Kicking accuracy between garment conditions was only significantly different when kicking with the dominant leg ( p = 0.002). Kicking accuracy was reduced in the fitted CG condition compared to the oversized CG (mean difference = 20 cm, p = 0.018) and for fitted CGs compared to training shorts (mean difference = 21 cm, p = 0.003) indicating that the fitted CGs had a negative effect on kicking accuracy. As these compression garments are worn regularly during training, further research is required to determine the long-term effect on skill development.
The Practice of Sport Psychology: A Youth Coaches' Perspective
Authors: Barker Stephanie , Winter Stacy
Published: May 2014

This research qualitatively documents youth sport coaches' perspectives of sport psychology and sport psychology consultants (SPCs) in the United Kingdom. Youth coaches are a unique population yet to be examined, despite their significance to the development of athletes. Semi-structured interviews were conducted with eight coaches who held a minimum of ten years experience with youth performers of a county to national level. Participants represented American football, hockey, soccer, and track and field. Inductive analysis identified twenty-four higher order themes, resulting in eight general dimensions: Role of sport psychology and SPCs, a sport psychologist's clientele, perceived work for sport psychologists, perception of where sport psychology belongs, expected characteristics of SPCs, professional accountability, and the facilitators and barriers of sport psychology. Results indicate youth coaches' support for the field of sport psychology, but the barriers SPCs face within youth sport are discussed. Consequently this article offers practitioners with applied solutions to overcome potential obstacles and improve current practices.
The Relationship between Speed and Technical Development in Young Speed Skaters
Authors: Hillis Tracy L. , Holman Shawn
Published: May 2014

The Long Term Athletic Development Plan (LTAD) defines the first ‘window of accelerated adaptation to speed’ or a ‘critical’ period of speed development as occurring during the FUNdamentals stage, age six to eight for girls and seven to nine for boys respectively. However, technical sport specific skill development is not recommended until the Learn to Train Stage. Utilizing a model of body composition, this study looks at the relationship between technical and speed development in young speed skaters ages 3 – 15. The results indicate that in both females and males, individuals with larger body composition had faster speeds but individuals with smaller body composition and with greater technical skill were as fast as or faster than those with larger body composition regardless of technical skill. The results support the conclusion that no “windows of trainability” for speed development need to exist as long as technical components are taught early to build neurological connections and fortify coordination to develop speed prepubescent, and technical development is maintained to allow skaters to adjust to increased muscular strength during pubescence and post-pubescence.
The Incidence of Match and Training Injuries in Rugby League: A Pooled Data Analysis of Published Studies
Authors: King Doug , Gissane Conor , Clark Trevor , Marshall Stephen W.
Published: May 2014

Studies reporting on injuries in rugby league have shown that the injury incidence increases as the participation level increases. To provide pooled estimates for the incidence of rugby league injuries in match and training activities at all levels of performance and by gender. Searches of PubMed, CINHAL, Ovid, MEDLINE, SCOPUS, ScienceDirect and SportDiscus® databases were performed to identify studies published in English prior to November 2012. Bibliographic searches were also carried out without language restrictions. A pooled analysis of published studies which have reported the incidences of rugby league match and/or training injuries. Two reviewers extracted the study characteristics, numerical data and assessed the quality, by adhering to the protocol for systematic review of observational studies (MOOSE). A total of 34 studies (from 1,422 identified in the initial search) were identified that reported data collection of rugby league injuries that met the inclusion criteria. The data provided information from a total of 5,785 match events totalling 87,185 match exposure hr. and 242,754 training exposure hr. The pooled analysis injury incidence for match injuries was 148 (95% CI: 145 to 150) per 1,000 match hr. The lower limb (69; 95% CI: 67 to 72 per 1,000 match hr.) was the most common injury region recorded. Although contusions were the most common pooled injury type (34.0; 95% CI: 32.3 to 35.8 per 1,000 match hr.) this varied by participation level. The pooled analysis injury incidence for training injuries was 12.6 per 1,000 training hr. The lower limb was again the most common injury region recorded (5.7; 95% CI: 5.1 to 5.8 per 1,000 training injuries) for all training studies and strains (3.1; 95% CI: 2.8 to 3.3 per 1,000 training hours) were the most common training injury type recorded. These findings are indicative of the physical demands placed on players across many levels of participation and in time further additions to this analysis are warranted to provide a more detailed picture of the sport from an injury prevention perspective.
RAID: a comprehensive resource for human RNA-associated (RNA–RNA/RNA–protein) interaction
Authors: Zhang Xiaomeng , Wu Deng , Chen Liqun , Li Xiang , Yang Jinxurong , Fan Dandan , Dong Tingting , Liu Mingyue , Tan Puwen , Xu Jintian , Yi Ying , Wang Yuting , Zou Hua , Hu Yongfei , Fan Kaili , Kang Juanjuan , Huang Yan , Miao Zhengqiang , Bi Miaoman , Jin Nana , Li Kongning , Li Xia , Xu Jianzhen , Wang Dong
Published: May 2014

Transcriptomic analyses have revealed an unexpected complexity in the eukaryote transcriptome, which includes not only protein-coding transcripts but also an expanding catalog of noncoding RNAs (ncRNAs). Diverse coding and noncoding RNAs (ncRNAs) perform functions through interaction with each other in various cellular processes. In this project, we have developed RAID (http://www.rna-society.org/raid), an RNA-associated (RNA–RNA/RNA–protein) interaction database. RAID intends to provide the scientific community with all-in-one resources for efficient browsing and extraction of the RNA-associated interactions in human. This version of RAID contains more than 6100 RNA-associated interactions obtained by manually reviewing more than 2100 published papers, including 4493 RNA–RNA interactions and 1619 RNA–protein interactions. Each entry contains detailed information on an RNA-associated interaction, including RAID ID, RNA/protein symbol, RNA/protein categories, validated method, expressing tissue, literature references (Pubmed IDs), and detailed functional description. Users can query, browse, analyze, and manipulate RNA-associated (RNA–RNA/RNA–protein) interaction. RAID provides a comprehensive resource of human RNA-associated (RNA–RNA/RNA–protein) interaction network. Furthermore, this resource will help in uncovering the generic organizing principles of cellular function network.
Constitucionalismo principialista y constitucionalismo garantista
Authors: Ferrajoli Luigi
Published: May 2014

En este artículo, el autor presenta las diferencias más relevantes entre el neoconstitucionalismo y el constitucionalismo garantista. En primer lugar, afirma que el constitucionalismo puede ser concebido de dos formas opuestas: como una superación del positivismo jurídico en sentido tendencialmente iusnaturalista o como su expansión o perfeccionamiento, realizando para llevar a cabo esta labor una revisión terminológica. En segundo lugar, el autor considera que si las constituciones incorporan principios de justicia de carácter ético-político desaparece el principal rasgo distintivo del positivismo jurídico: la separación entre Derecho y moral o entre validez y justicia. A continuación, considera al constitucionalismo garantista como un iuspositivismo reforzado, completando al Estado de Derecho porque comporta el sometimiento al Derecho y al control de constitucionalidad. En cuarto lugar, el autor afirma que la tesis de que todo ordenamiento jurídico satisface objetivamente algún «mínimo ético» no es más que la vieja tesis iusnaturalista, que termina por convertirse en la actual versión del legalismo ético que es el constitucionalismo ético, en virtud del cual los principios constitucionales se pretenden objetivamente justos. En quinto lugar, el autor realiza una crítica a la contraposición entre principios y reglas, en los que se basa una concepción de la constitución y del constitucionalismo opuesta a la concepción positivista y garantista. En sexto lugar, el autor afirma que la idea de que los principios constitucionales son siempre objeto de ponderación y no de aplicación genera un peligro para la independencia de la jurisdicción y para su legitimación política. Finalmente, el autor considera que el constitucionalismo conlleva un debilitamiento y virtualmente un colapso de la normatividad de los principios constitucionales, así como una degradación de los derechos fundamentales establecidos en ellas a meras recomendaciones genéricas de carácter ético-político.
Semántica, pragmática y democracia
Authors: Greppi Andrea
Published: May 2014

Esta nota regresa, una vez más, al debate sobre la intangibilidad de los derechos fundamentales y lo hace tomando como punto de referencia la distinción, elaborada en Principia iuris de Luigi Ferrajoli, entre semántica y pragmática del lenguaje jurídico. Tras una crítica de la semántica convencionalista que subyace al constitucionalismo garantista de Ferrajoli se afirma que los puentes entre la lengua del Derecho y el habla de los ciudadanos, en democracia, han de permanecer abiertos al escrutinio público. El objetivo de este comentario es afirmar que, al menos en este ámbito, el campo del constitucionalismo garantista no es tan homogéneo como se desprende de la caracterización que de él ofrece Luigi Ferrajoli en sus últimos escritos.
Principios, ponderación, y la separación entre derecho y moral: sobre el neoconstitucionalismo y sus críticos
Authors: Pino Giorgio
Published: May 2014

En el ensayo Constitucionalismo principialista y constitucionalismo garantista, Luigi Ferrajoli ofrece una oportuna clarificación teórica y conceptual sobre el así llamado neoconstitucionalismo. Por mi parte, en esta contribución intentaré desarrollar algunas observaciones sobre tres puntos acerca de los cuales me encuentro en relativo desacuerdo con el análisis de Ferrajoli: el tratamiento de la distinción entre reglas y principios, la interpretación de la práctica de la ponderación, y el problema de la separación entre Derecho y moral. Además, ofreceré un panorama de los significados del (neo)constitucionalismo, y, respecto a tal panorama, consideraré el modo en el cual Ferrajoli sitúa su propia posición teórica.
El paradigma constitucionalista de la autoridad jurídica
Authors: Redondo María Cristina
Published: May 2014

En este trabajo discuto algunos de los problemas señalados por Luigi Ferrajoli en su artículo: «Constitucionalismo principialista y constitucionalismo garantista». En primer lugar, en consonancia con las tesis de Ferrajoli, intento sostener que el constitucionalismo ha de ser interpretado como el reconocimiento explícito de un nuevo paradigma de autoridad jurídica y de Derecho, y que la teoría jurídica positivista-normativista ofrece la mejor explicación de este nuevo paradigma. En segundo lugar, intento mostrar que un constitucionalismo iusnaturalista o iusrealista serían auto-contradictorios. Estas teorías explican incorrectamente las normas constitucionales que imponen límites sustantivos a la autoridad jurídica (los derechos fundamentales) y asumen tesis que contradicen la propuesta central del constitucionalismo. A lo largo del análisis me concentro en la idea de balance para destacar dos cosas. En primer lugar, que el constitucionalismo garantista de Ferrajoli implica que estos derechos son normas que están relativamente determinadas por el paradigma vigente en la práctica y que, en tal medida, no se identifican ni aplican mediante balances. En segundo lugar, que dicha tesis es totalmente compatible con reconocer que tales derechos —que devienen parte de los criterios últimos de validez en un sistema constitucionalista—, si bien en modo limitado, admiten una pluralidad de interpretaciones y están potencialmente en conflicto. En tal medida, ellos efectivamente están sujetos a balances.
Validez material y constitucionalismo garantista
Authors: Ródenas Calatayud Ángeles
Published: May 2014

El objeto de este artículo es poner de relieve una contradicción insalvable en el constitucionalismo garantista de Ferrajoli: de un lado, el constitucionalismo garantista se opone rotundamente a la ponderación, confiando la resolución de los conflictos de validez material a la simple subsunción y a la aplicación del criterio de jerarquía normativa; pero, de otro lado, la concepción de Ferrajoli precisa de una noción amplia de validez normativa, que dé cuenta de aquellos conflictos normativos en los que diversos principios constitucionales pugnan entre sí a la hora de fundamentar un juicio de validez material acerca de una cierta norma.
Un diálogo sobre principios constitucionales
Authors: Ferrajoli Luigi , Ruiz Manero Juan
Published: May 2014

En este diálogo, los autores comparan el enfoque de los principios constitucionales «regulativos» o «en sentido estricto» y de las directrices constitucionales en el «constitucionalismo garantista» defendido por Ferrajoli y en el «constitucionalismo principialista» en el que se reconoce Ruiz Manero.
Evaluation of growth functions used in the Swedish Forest Planning System Heureka
Authors: Fahlvik Nils , Elfving Björn , Wikström Peder
Published: May 2014

The performance of growth models implemented in the Swedish Forest Planning System Heureka was evaluated. Four basal area growth models were evaluated by comparing their predictions to data from five-year growth records for 1711 permanent sample plots of the National Forest Inventory (NFI-data). Also, two alternative implementations of Heureka, including a combined stand- and tree-level basal area growth model and a single tree-level model, respectively, were evaluated using data from 57 blocks in a thinning experiment (GG-data) involving Scots pine ( L.) and Norway spruce ( (L.) Karst) in which the trees were monitored for 30 years after the first thinning. The predicted volume growth was also compared to observed values. Growth models based on data from 1970âs and 1980âs overestimated growth in the NFI test plots from the early 2000âs by about 3%. Stand-level models had larger precision than tree-level models. Basal area growth was underestimated in dense NFI-plots and overestimated in non-thinned GG-plots, illustrating an un-solved modelling problem. Basal area growth was overestimated by 2â5% also in the GG-plots over the whole observation period. Volume growth was however accurately predicted for pine and underestimated by 2% for spruce. The relative prediction error did not increase with increasing length of prediction period. Thinning response models calibrated with GG-data worked well in the total application and produced growth levels for different thinning alternatives in line with observations.Pinus sylvestrisPicea abies
Modulation ofC. elegansTouch Sensitivity Is Integrated at Multiple Levels
Authors: Chen Xiaoyin , Chalfie Martin
Published: May 2014

Sensory systems can adapt to different environmental signals. Here we identify four conditions that modulate anterior touch sensitivity inCaenorhabditis elegansafter several hours and demonstrate that such sensory modulation is integrated at multiple levels to produce a single output. Prolonged vibration involving integrin signaling directly sensitizes the touch receptor neurons (TRNs). In contrast, hypoxia, the dauer state, and high salt reduce touch sensitivity by preventing the release of long-range neuroregulators, including two insulin-like proteins. Integration of these latter inputs occurs at upstream neurohormonal cells and at the insulin signaling cascade within the TRNs. These signals and those from integrin signaling converge to modulate touch sensitivity by regulating AKT kinases and DAF-16/FOXO. Thus, activation of either the integrin or insulin pathways can compensate for defects in the other pathway. This modulatory system integrates conflicting signals from different modalities, and adapts touch sensitivity to both mechanical and non-mechanical conditions.
Human Memory Retrieval and Inhibitory Control in the Brain: Beyond Correlational Evidence
Authors: Penolazzi Barbara , Stramaccia Davide Francesco , Braga Miriam , Mondini Sara , Galfano Giovanni
Published: May 2014

Retrieving information from long-term memory can result in the episodic forgetting of related material. One influential account states that this retrieval-induced forgetting (RIF) phenomenon reflects inhibitory mechanisms called into play to decrease retrieval competition. Recent neuroimaging studies suggested that the prefrontal cortex, which is critically engaged in inhibitory processing, is also involved in retrieval competition situations. Here, we used transcranial direct current stimulation (tDCS) to address whether inhibitory processes could be causally linked to RIF. tDCS was administered over the right dorsolateral prefrontal cortex during the retrieval-practice phase in a standard retrieval-practice paradigm. Sixty human participants were randomly assigned to anodal, cathodal, or sham-control groups. The groups showed comparable benefits for practiced items. In contrast, unlike both the sham and anodal groups, the cathodal group exhibited no RIF. This pattern is interpreted as evidence for a causal role of inhibitory mechanisms in episodic retrieval and forgetting.
Diacylglycerol Activates the Light-Dependent Channel TRP in the Photosensitive Microvilli ofDrosophila melanogasterPhotoreceptors
Authors: Delgado Ricardo , Muñoz Yorka , Peña-Cortés Hugo , Giavalisco Patrick , Bacigalupo Juan
Published: May 2014

Drosophilalight-dependent channels, TRP and TRPL, reside in the light-sensitive microvilli of the photoreceptor's rhabdomere. Phospholipase C mediates TRP/TRPL opening, but the gating process remains unknown. Controversial evidence has suggested diacylglycerol (DAG), polyunsaturated fatty acids (PUFAs, a DAG metabolite), phosphatidylinositol bisphosphate (PIP2), and H+as possible channel activators. We tested each of them directly in inside-out TRP-expressing patches excised from the rhabdomere, making use of mutants and pharmacology. When patches were excised in darkness TRP remained closed, while when excised under illumination it stayed constitutively active. TRP was opened by DAG and silenced by ATP, suggesting DAG-kinase (DGK) involvement. The ATP effect was abolished by inhibiting DGK and in therdgAmutant, lacking functional DGK, implicating DGK. DAG activated TRP even in the presence of a DAG-lipase inhibitor, inconsistent with a requirement of PUFAs in opening TRP. PIP2had no effect and acidification, pH 6.4, activated TRP irreversibly, unlike the endogenous activator. Complementary liquid-chromatography/mass-spectrometry determinations of DAG and PUFAs in membranes enriched in rhabdomere obtained from light- and dark-adapted eyes showed light-dependent increment in six DAG species and no changes in PUFAs. The results strongly support DAG as the endogenous TRP agonist, as some of its vertebrate TRPC homologs of the same channel family.
Ionic Mechanisms of Microsecond-Scale Spike Timing in Single Cells
Authors: Markham Michael R. , Zakon Harold H.
Published: May 2014

Electric fish image their environments and communicate by generating electric organ discharges through the simultaneous action potentials (APs) of electric organ cells (electrocytes) in the periphery.Steatogenys elegansgenerates a biphasic electrocyte discharge by the precisely regulated timing and waveform of APs generated from two excitable membranes present in each electrocyte. Current-clamp recordings of electrocyte APs reveal that the posterior membrane fires first, followed ∼30 μs later by an AP on the anterior membrane. This delay was maintained even as the onset of the first AP was advanced >5 ms by increasing stimulus intensity and across multiple spikes during bursts of APs elicited by prolonged stimulation. Simultaneous cell-attached loose-patch recordings of Na+currents on each membrane revealed that activation voltage for Na+channels on the posterior membrane was 10 mV hyperpolarized compared with Na+channels on the anterior membrane, with no differences in activation or inactivation kinetics. Computational simulations of electrocyte APs demonstrated that this difference in Na+current activation voltage was sufficient to maintain the proper firing order and the interspike delay. A similar difference in activation threshold has been reported for the Na+currents of the axon initial segment compared with somatic Na+channels of pyramidal neurons, suggesting convergent evolution of spike initiation and timing mechanisms across different systems of excitable cells.
Hippocampal Replay Captures the Unique Topological Structure of a Novel Environment
Authors: Wu Xiaojing , Foster David J.
Published: May 2014

Hippocampal place-cell replay has been proposed as a fundamental mechanism of learning and memory, which might support navigational learning and planning. An important hypothesis of relevance to these proposed functions is that the information encoded in replay should reflect the topological structure of experienced environments; that is, which places in the environment are connected with which others. Here we report several attributes of replay observed in rats exploring a novel forked environment that support the hypothesis. First, we observed that overlapping replays depicting divergent trajectories through the fork recruited the same population of cells with the same firing rates to represent the common portion of the trajectories. Second, replay tended to be directional and to flip the represented direction at the fork. Third, replay-associated sharp-wave–ripple events in the local field potential exhibited substructure that mapped onto the maze topology. Thus, the spatial complexity of our recording environment was accurately captured by replay: the underlying neuronal activities reflected the bifurcating shape, and both directionality and associated ripple structure reflected the segmentation of the maze. Finally, we observed that replays occurred rapidly after small numbers of experiences. Our results suggest that hippocampal replay captures learned information about environmental topology to support a role in navigation.
Distinct KvChannel Subtypes Contribute to Differences in Spike Signaling Properties in the Axon Initial Segment and Presynaptic Boutons of Cerebellar Interneurons
Authors: Rowan Matthew J. M. , Tranquil Elizabeth , Christie Jason M.
Published: May 2014

The discrete arrangement of voltage-gated K+(Kv) channels in axons may impart functional advantages in action potential (AP) signaling yet, in compact cell types, the organization of Kvchannels is poorly understood. We find that in cerebellar stellate cell interneurons of mice, the composition and influence of Kvchannels populating the axon is diverse and depends on location allowing axonal compartments to differentially control APs in a local manner. Kv1 channels determine AP repolarization at the spike initiation site but not at more distal sites, limiting the expression of use-dependent spike broadening to the most proximal axon region, likely a key attribute informing spiking phenotype. Local control of AP repolarization at presynaptic boutons depends on Kv3 channels keeping APs brief, thus limiting Ca2+influx and synaptic strength. These observations suggest that AP repolarization is tuned by the local influence of distinct Kvchannel types, and this organization enhances the functional segregation of axonal compartments.
Imaging Light Responses of Foveal Ganglion Cells in the Living Macaque Eye
Authors: Yin Lu , Masella Benjamin , Dalkara Deniz , Zhang Jie , Flannery John. G. , Schaffer David V. , Williams David R. , Merigan William H.
Published: May 2014

The fovea dominates primate vision, and its anatomy and perceptual abilities are well studied, but its physiology has been little explored because of limitations of current physiological methods. In this study, we adapted a novelin vivoimaging method, originally developed in mouse retina, to explore foveal physiology in the macaque, which permits the repeated imaging of the functional response of many retinal ganglion cells (RGCs) simultaneously. A genetically encoded calcium indicator, G-CaMP5, was inserted into foveal RGCs, followed by calcium imaging of the displacement of foveal RGCs from their receptive fields, and their intensity-response functions. The spatial offset of foveal RGCs from their cone inputs makes this method especially appropriate for fovea by permitting imaging of RGC responses without excessive light adaptation of cones. This new method will permit the tracking of visual development, progression of retinal disease, or therapeutic interventions, such as insertion of visual prostheses.
Complementary Interactions between Command-Like Interneurons that Function to Activate and Specify Motor Programs
Authors: Wu Jin-Sheng , Wang Nan , Siniscalchi Michael J. , Perkins Matthew H. , Zheng Yu-Tong , Yu Wei , Chen Song-an , Jia Ruo-nan , Gu Jia-Wei , Qian Yi-Qing , Ye Yang , Vilim Ferdinand S. , Cropper Elizabeth C. , Weiss Klaudiusz R. , Jing Jian
Published: May 2014

Motor activity is often initiated by a population of command-like interneurons. Command-like interneurons that reliably drive programs have received the most attention, so little is known about how less reliable command-like interneurons may contribute to program generation. We study two electrically coupled interneurons, cerebral-buccal interneuron-2 (CBI-2) and CBI-11, which activate feeding motor programs in the molluskAplysia californica. Earlier work indicated that, in rested preparations, CBI-2, a powerful activator of programs, can trigger ingestive and egestive programs. CBI-2 reliably generated ingestive patterns only when it was repeatedly stimulated. The ability of CBI-2 to trigger motor activity has been attributed to the two program-promoting peptides it contains, FCAP and CP2. Here, we show that CBI-11 differs from CBI-2 in that it contains FCAP but not CP2. Furthermore, it is weak in its ability to drive programs. On its own, CBI-11 is therefore less effective as a program activator. When it is successful, however, CBI-11 is an effective specifier of motor activity; that is, it drives mostly ingestive programs. Importantly, we found that CBI-2 and CBI-11 complement each other's actions. First, prestimulation of CBI-2 enhanced the ability of CBI-11 to drive programs. This effect appears to be partly mediated by CP2. Second, coactivation of CBI-11 with CBI-2 makes CBI-2 programs immediately ingestive. This effect may be mediated by specific actions that CBI-11 exerts on pattern-generating interneurons. Therefore, different classes of command-like neurons in a motor network may make distinct, but potentially complementary, contributions as either activators or specifiers of motor activity.
DAPK1–p53 Interaction Converges Necrotic and Apoptotic Pathways of Ischemic Neuronal Death
Authors: Pei Lei , Shang You , Jin Huijuan , Wang Shan , Wei Na , Yan Honglin , Wu Yan , Yao Chengye , Wang Xiaoxi , Zhu Ling-Qiang , Lu Youming
Published: May 2014

Necrosis and apoptosis are two distinct types of mechanisms that mediate ischemic injury. But a signaling point of convergence between them has yet to be identified. Here, we show that activated death-associated protein kinase 1 (DAPK1), phosphorylates p53 at serine-23 (pS23) via a direct binding of DAPK1 death domain (DAPK1DD) to the DNA binding motif of p53 (p53DM). We uncover that thepS23acts as a functional version of p53 and mediates necrotic and apoptotic neuronal death; in the nucleus,pS23induces the expression of proapoptotic genes, such asBax, whereas in the mitochondrial matrix,pS23triggers necrosis via interaction with cyclophilin D (CypD) in cultured cortical neurons from mice. Deletion of DAPK1DD (DAPK1DDΔ) or application of Tat-p53DM that interrupts DAPK1–p53 interaction blocks these dual pathways ofpS23actions in mouse cortical neurons. Thus, the DAPK1–p53 interaction is a signaling point of convergence of necrotic and apoptotic pathways and is a desirable target for the treatment of ischemic insults.
Repetition Probability Effects Depend on Prior Experiences
Authors: Grotheer Mareike , Kovács Gyula
Published: May 2014

The magnitude of repetition suppression (RS) in the Fusiform Face Area is influenced by the probability of repetitions of faces (Summerfield et al., 2008), implying that perceptual expectations affect repetition-related processes. Surprisingly, however, macaque single-cell (Kaliukhovich and Vogels, 2011) and human fMRI (Kovács et al., 2013) studies have failed to find repetition probability [P(rep)] modulations of RS with nonface stimuli in the occipitotemporal cortex, suggesting that the effect is face specific. One possible explanation of this category selectivity is that the extensive experience humans have with faces affects the neural mechanisms of RS specifically, creating P(rep) modulatory effects. To address this question, we used fMRI to test the P(rep) effects for another well trained stimulus category, upright letters of the roman alphabet as well as for unfamiliar false fonts. We observed significant RS for both stimulus sets in the Letter Form Area as well as in the caudodorsal part of the lateral occipital complex. Interestingly, the influence of P(rep) on RS was dependent on the stimulus: while we observed P(rep) modulations for the roman letters, no such effects were found for the unfamiliar false fonts in either area. Our findings suggest that P(rep) effects on RS are manifest for nonface stimuli as well, but that they depend on the experience of the subjects with the stimulus category. This shows, for the first time, that prior experience affects the influence of contextual predictive information on RS in the human occipitotemporal cortex.
Depletion of Perineuronal Nets in the Amygdala to Enhance the Erasure of Drug Memories
Authors: Xue Yan-Xue , Xue Li-Fen , Liu Jian-Feng , He Jia , Deng Jia-Hui , Sun Shi-Chao , Han Hai-Bin , Luo Yi-Xiao , Xu Ling-Zhi , Wu Ping , Lu Lin
Published: May 2014

Extinction therapy has been suggested to suppress the conditioned motivational effect of drug cues to prevent relapse. However, extinction forms a new inhibiting memory rather than erasing the original memory trace and drug memories invariably return. Perineuronal nets (PNNs) are a specialized extracellular matrix around interneurons in the brain that have been suggested to be a permissive factor that allows synaptic plasticity in the adolescent brain. The degradation of PNNs caused by chondroitinase ABC (ChABC) may generate induced juvenile-like plasticity (iPlasticity) and promote experience-dependent plasticity in the adult brain. In the present study, we investigated the effect of removing PNNs in the amygdala of rat on the extinction of drug memories. We found that extinction combined with intra-amygdala injections of ChABC (0.01 U/side) prevented the subsequent priming-induced reinstatement of morphine-induced and cocaine-induced, but not food -induced, conditioned place preference (CPP). Intra-amygdala injections of ChABC alone had no effect on the retention, retrieval, or relearning of morphine-induced CPP and storage of acquired food-induced CPP. Moreover, we found that the procedure facilitated the extinction of heroin- and cocaine-seeking behavior and prevented the spontaneous recovery and drug-induced reinstatement of heroin- and cocaine-seeking behavior. We also found that the effect of PNNs degradation combined with extinction may be mediated by the potentiation of several plasticity-related proteins in the amygdala. Altogether, our findings demonstrate that a combination of extinction training with PNNs degradation in the amygdala erases drug memories and suggest that ChABC may be an attractive candidate for the prevention of relapse.
Plasma osteocalcin levels as a predictor of cardiovascular disease in older men and women: a population-based cohort study
Authors: Holvik Kristin , van Schoor Natasja M , Eekhoff Elisabeth M W , den Heijer Martin , Deeg Dorly J H , Lips Paul , de Jongh Renate
Published: May 2014

Objective

The role of osteocalcin (OC) in cardiovascular disease (CVD) is unresolved. We aimed to study the association between plasma OC concentrations and the risk of non-fatal and fatal CVDs. We also aimed to investigate whether such an association, if present, would be mediated by established metabolic risk factors.

Design

A population-based longitudinal cohort study.

Methods

In 1995/1996, OC was determined in blood samples drawn from 1319 subjects aged 65–88 years participating in the Longitudinal Aging Study Amsterdam in 1995/1996. The self-reported CVD events were collected every 3 years until 2005/2006, and CVD deaths until 1st January 2007. Cox proportional hazards regression was performed, considering potential confounders (smoking, physical activity, and BMI) and mediators (blood pressure, plasma triglycerides, total and HDL cholesterol, fructosamine, and aortic calcification).

Results

During the median 4.1 years follow-up, 709 subjects (53.8%) suffered a CVD event. There was no overall association between OC and CVD: hazard ratio (HR) was 0.97 (95% CI 0.90–1.04) per nmol/l higher plasma OC, adjusted for age and sex. There was a statistical interaction between plasma OC, age, and sex on CVD (P=0.014). In those subjects aged ≥75 years, age-adjusted HRs (95% CI) were 0.86 (0.75–0.99) in men and 1.16 (1.03–1.31) in women per nmol/l higher plasma OC. Adjustment for covariates only slightly attenuated the association in older-old men, but did not affect the association in older-old women.

Conclusion

A higher plasma OC concentration was associated with a reduced risk of CVD in older-old men and with an increased risk of CVD in older-old women. We found no evidence that this was mediated by arterial calcification or metabolic risk factors.
TRANSITION IN ENDOCRINOLOGY: Management of Klinefelter syndrome during transition
Authors: Gies Inge , Unuane David , Velkeniers Brigitte , De Schepper Jean
Published: May 2014

Klinefelter syndrome (KS) is the most common sex chromosomal disorder in males. Key findings in older adolescents and young men are small testes with variable hypo-androgenism, but almost universal azoospermia, most frequently in combination with a history of learning difficulties and behavior problems. Males with KS may come to medical attention through different medical presentations, given its association with several congenital malformations, and psychiatric, endocrine, and metabolic disorders. Preventive care is to be provided from diagnosis, preferentially through a multidisciplinary approach, including that from an endocrinologist, clinical psychologist or psychiatrist, neurologist, urologist, geneticist, sexologist, and a fertility team. Accurate information about the condition and assessment of associated medical conditions should be offered at diagnosis and should be followed by psychological counseling. Medical treatment during transition into adulthood is focused on fertility preservation and testosterone replacement therapy in the case of hypo-androgenism, and alleviation of current or future consequences of testicular fibrosis. However, more research is needed to determine the need for pro-active testosterone treatment in adolescence, as well as the conditions for an optimal testosterone replacement and sperm retrieval in adolescents and young men with KS. Furthermore, screening for associated diseases such as metabolic syndrome, autoimmune diseases, thyroid dysfunction, and malignancies is warranted during this period of life. The practical medical management during transition and, more specifically, the role of the endocrinologist are discussed in this article.
De novo morphogenesis of testis tissue: an improved bioassay to investigate the role of VEGF165 during testis formation
Authors: Dores Camila , Dobrinski Ina
Published: May 2014

De novo formation of testis tissue from single-cell suspensions allows manipulation of different testicular compartments before grafting to study testicular development and the spermatogonial stem cell niche. However, the low percentages of newly formed seminiferous tubules supporting complete spermatogenesis and lack of a defined protocol have limited the use of this bioassay. Low spermatogenic efficiency in de novo formed tissue could result from the scarcity of germ cells in the donor cell suspension, cell damage caused by handling or from hypoxia during tissue formation in the host environment. In this study, we compared different proportions of spermatogonia in the donor cell suspension and the use of Matrigel as a scaffold to support de novo tissue formation and spermatogenesis. Then, we used the system to investigate the role of vascular endothelial growth factor 165 (VEGF165) during testicular morphogenesis on blood vessel and seminiferous tubule formation, and on presence of germ cells in the de novo developed tubules. Our results show that donor cell pellets with 10×106 porcine neonatal testicular cells in Matrigel efficiently formed testis tissue de novo. Contrary to what was expected, the enrichment of the cell suspension with germ cells did not result in higher numbers of tubules supporting spermatogenesis. The addition of VEGF165 did not improve blood vessel or tubule formation, but it enhanced the number of tubules containing spermatogonia. These results indicate that spermatogenic efficiency was improved by the addition of Matrigel, and that VEGF165 may have a protective role supporting germ cell establishment in their niche.
Distinct roles of ROCK1 and ROCK2 during development of porcine preimplantation embryos
Authors: Zhang Jin Yu , Dong Huan Sheng , Oqani Reza K , Lin Tao , Kang Jung Won , Jin Dong Il
Published: May 2014

Cell-to-cell contact mediated by cell adhesion is fundamental to the compaction process that ensures blastocyst quality during embryonic development. In this study, we first showed that Rho-associated coiled-coil protein kinases (ROCK1 and ROCK2) were expressed both in porcine oocytes and IVF preimplantation embryos, playing different roles in oocytes maturation and embryo development. The amount of mRNA encoding ROCK1 and the protein concentration clearly increased between the eight-cell and morula stages, but decreased significantly when blastocysts were formed. Conversely, ROCK2 was more abundant in the blastocyst compared with other embryonic stages. Moreover, immunostaining showed that ROCK1 protein distribution changed as the embryo progressed through cleavage and compaction to the morula stage. Initially, the protein was predominantly associated with the plasma membrane but later became cytoplasmic. By contrast, ROCK2 protein was localized in both the cytoplasm and the spindle rotation region during oocyte meiosis, but in the cytoplasm and nucleus as the embryo developed. In addition, ROCK2 was present in the trophectoderm cells of the blastocyst. Treatment with 15 μM Y27632, a specific inhibitor of ROCKs, completely blocked further development of early four-cell stage embryos. Moreover, we did not detect the expression ofROCK1but did detectROCK2expression in blastocysts. Moreover, lysophosphatidic acid an activator of ROCKs significantly improved the rates of blastocyst formation. These data demonstrate that ROCKs are required for embryo development to the blastocyst stage. Together, our results indicate that ROCK1 and ROCK2 may exert different biological functions during the regulation of compaction and in ensuring development of porcine preimplantation embryos to the blastocyst stage.
Budding Yeast for Budding Geneticists: A Primer on the Saccharomyces cerevisiae Model System
Authors: Duina Andrea A , Miller Mary E , Keeney Jill B
Published: May 2014

The budding yeast Saccharomyces cerevisiae is a powerful model organism for studying fundamental aspects of eukaryotic cell biology. This Primer article presents a brief historical perspective on the emergence of this organism as a premier experimental system over the course of the past century. An overview of the central features of the S. cerevisiae genome, including the nature of its genetic elements and general organization, is also provided. Some of the most common experimental tools and resources available to yeast geneticists are presented in a way designed to engage and challenge undergraduate and graduate students eager to learn more about the experimental amenability of budding yeast. Finally, a discussion of several major discoveries derived from yeast studies highlights the far-reaching impact that the yeast system has had and will continue to have on our understanding of a variety of cellular processes relevant to all eukaryotes, including humans.
Enhancing the Efficiency of a PEM Hydrogen Fuel Cell with Synthesized Metal-Nanoparticle/Graphene Composites Synergy
Authors: Isseroff Rebecca , Akhavan Benjamin , Pan Cheng , He Harry Shan , Sokolov Jonathan , Rafailovich Miriam
Published: May 2014

Obstructing commercialization of Proton Exchange Membrane Fuel Cells (PEMFC) is the soaring cost of platinum and other catalysts used to increase membrane efficiency. The goal of this investigation is to find a relatively inexpensive catalyst for coating the membrane and enhancing the efficiency of the PEMFC. Graphene oxide was reduced using NaBH4 in the presence of metal salts, primarily KAuCl4 and K2PtCl4, to synthesize metal-nanoparticle/reduced graphene oxide (RGO). FTIR indicated the successful synthesis of RGO, while Transmission Electron Microscopy displayed the presence of nanoparticles on RGO sheets. Nafion® membranes were coated with metal-nanoparticle/RGO and tested in an experimental PEMFC alongside bare Nafion®, Gold (Au) nanoparticles, and RGO. The metal-nanoparticle/RGO composites enhanced the PEMFC compared to bare Nafion®. Au-RGO, the best catalyst composite, increased the efficiency up to 150% better than nanoparticles or RGO alone while using only 1% of the concentration of Au nanoparticles. Theoretical power output of the Au-RGO synergy could increase fuel cell efficiency up to 18 times more than the Au-nanoparticles themselves by altering concentrations of Au nanoparticles in Au-RGO. The Au nanoparticles changed the structure and catalytic ability of graphene in the Au-RGO, offering a promising future for PEM fuel cell technology.